Generic Environmental Impact 

Statement for License 

Renewal of Nuclear Plants

Supplement 48

Regarding South Texas 

Project, Units 1 and 2 

Final Report

Office of Nuclear Reactor Regulation

NUREG-1437

Supplement 48
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Generic Environmental Impact 

Statement for License Renewal 

of Nuclear Plants

Supplement 48

Regarding South Texas 

Project, Units 1 and 2

Final Report

Manuscript Completed: October 2013

Date Published: November 2013

Office of Nuclear Reactor Regulation

NUREG-1437

Supplement 48
NUREG-1437, Supplement 48, has been 

reproduced from the best available copy.
iii

ABSTRACT

This supplemental environmental impact statement (SEIS) has been prepared in response to an 

application submitted by STP Nuclear Operating Company (STPNOC) to renew the operating 

licenses for South Texas Project (STP), Units 1 and 2, for an additional 20 years.

This SEIS includes the analysis that evaluates the environmental impacts of the proposed 

action and alternatives to the proposed action. Alternatives considered include new nuclear 

generation, natural gas-fired combined-cycle generation, supercritical coal-fired generation, 

combination alternative, purchased power, and not renewing the license (the no-action 

alternative).

The U.S. Nuclear Regulatory Commission staff’s (NRC’s) recommendation is that the adverse 

environmental impacts of license renewal for STP are not great enough to deny the option of 

license renewal for energy planning decisionmakers. This recommendation is based on the 

following:

• the analysis and findings in NUREG-1437, Volumes 1 and 2, Generic 

Environmental Impact Statement for License Renewal of Nuclear Plants; 

• the Environmental Report submitted by STPNOC; 

• consultation with Federal, state, local, and tribal government agencies; 

• the NRC’s environmental review; and

• consideration of public comments received during the scoping process. 

v 

TABLE OF CONTENTS

ABSTRACT................................................................................................................................iii

TABLE OF CONTENTS.............................................................................................................. v 

FIGURES................................................................................................................................. xiii 

TABLES.................................................................................................................................... xv 

EXECUTIVE SUMMARY .........................................................................................................xix

ABBREVIATIONS AND ACRONYMS ..................................................................................... xxv 

1.0 PURPOSE AND NEED FOR ACTION......................................................................... 1-1 

1.1 Proposed Federal Action.................................................................................. 1-1 

1.2 Purpose and Need for the Proposed Federal Action ........................................ 1-1 

1.3 Major Environmental Review Milestones.......................................................... 1-1 

1.4 Generic Environmental Impact Statement........................................................ 1-3 

1.5 Supplemental Environmental Impact Statement............................................... 1-5 

1.6 Cooperating Agencies...................................................................................... 1-6 

1.7 Consultations ................................................................................................... 1-6 

1.8 Correspondence .............................................................................................. 1-7 

1.9 Status of Compliance....................................................................................... 1-7 

1.10 References ...................................................................................................... 1-7 

2.0 AFFECTED ENVIRONMENT ...................................................................................... 2-1 

2.1 Facility Description........................................................................................... 2-1 

2.1.1 Reactor and Containment Systems ...................................................... 2-1 

2.1.2 Radioactive Waste Management.......................................................... 2-1 

2.1.3 Nonradiological Waste Management.................................................... 2-4 

2.1.4 Plant Operation and Maintenance ........................................................ 2-6 

2.1.5 Power Transmission System ................................................................ 2-6 

2.1.6 Cooling and Auxiliary Water Systems................................................... 2-8 

2.1.7 Facility Water Use and Quality ............................................................. 2-9 

2.2 Surrounding Environment .............................................................................. 2-12

2.2.1 Land Use............................................................................................ 2-13

2.2.2 Air Quality and Meteorology ............................................................... 2-13

2.2.3 Geologic Environment ........................................................................ 2-15

2.2.4 Surface Water Resources .................................................................. 2-17

2.2.5 Groundwater Resources..................................................................... 2-19

2.2.6 Aquatic Resources ............................................................................. 2-24

2.2.7 Terrestrial Resources ......................................................................... 2-38

2.2.8 Protected Species and Habitats ......................................................... 2-47

2.2.9 Socioeconomics ................................................................................. 2-63

2.2.10 Historic and Archaeological Resources .............................................. 2-75

2.3 Related Federal and State Activities .............................................................. 2-77
Table of Contents

vi

2.4 References .................................................................................................... 2-78

3.0 ENVIRONMENTAL IMPACTS OF REFURBISHMENT................................................ 3-1 

3.1 References ........................................................................................................... 3-3 

4.0 ENVIRONMENTAL IMPACTS OF OPERATION ......................................................... 4-1 

4.1 Land Use ......................................................................................................... 4-1 

4.2 Air Quality ........................................................................................................ 4-1 

4.3 Surface Water Resources ................................................................................ 4-2 

4.3.1 Generic Surface Water Issues.............................................................. 4-2 

4.3.2 Surface Water Use Conflicts—Plants Using Makeup Water from a 

Small River with Low Flow.................................................................... 4-3 

4.4 Groundwater Resources .................................................................................. 4-5 

4.4.1 Generic Groundwater Issues................................................................ 4-5 

4.4.2 Groundwater Use Conflicts................................................................... 4-6 

4.4.3 Groundwater Quality ............................................................................ 4-9 

4.5 Aquatic Resources......................................................................................... 4-11

4.5.1 Generic Aquatic Ecology Issues ......................................................... 4-12

4.5.2 Entrainment and Impingement............................................................ 4-12

4.5.3 Thermal Shock ................................................................................... 4-24

4.5.4 Mitigation............................................................................................ 4-26

4.6 Terrestrial Resources..................................................................................... 4-27

4.7 Protected Species and Habitats..................................................................... 4-28

4.7.1 Species and Habitats Protected Under the Endangered Species 

Act...................................................................................................... 4-28

4.7.2 Species Designated as NMFS Species of Concern ............................ 4-33

4.7.3 Species Protected Under the Bald and Golden Eagles Protection 

Act...................................................................................................... 4-33

4.7.4 Species Protected Under the Migratory Bird Treaty Act...................... 4-33

4.7.5 Species Protected Under the Marine Mammal Protection Act............. 4-33

4.7.6 Species Protected Under the Magnuson–Stevens Act........................ 4-33

4.7.7 Species Protected Under State of Texas Statutes .............................. 4-34

4.7.8 Conclusion ......................................................................................... 4-34

4.8 Human Health................................................................................................ 4-34

4.8.1 Generic Human Health Issues............................................................ 4-35

4.8.2 Radiological Impacts of Normal Operations........................................ 4-35

4.8.3 Microbiological Organisms ................................................................. 4-39

4.8.4 Electromagnetic Fields—Acute Effects............................................... 4-39

4.8.5 Electromagnetic Fields—Chronic Effects............................................ 4-41

4.9 Socioeconomics............................................................................................. 4-41

4.9.1 Generic Socioeconomic Issues .......................................................... 4-42

4.9.2 Housing.............................................................................................. 4-42
Table of Contents

vii

4.9.3 Public Services—Public Utilities ......................................................... 4-43

4.9.4 Public Services—Transportation ........................................................ 4-43

4.9.5 Offsite Land Use................................................................................. 4-43

4.9.6 Historic and Archaeological Resources .............................................. 4-45

4.9.7 Environmental Justice ........................................................................ 4-46

4.10 Evaluation of New and Potentially Significant Information.............................. 4-53

4.11 Environmental Issues Contained in the Revised 10 CFR Part 51, 

“Environmental Protection Regulations for Domestic Licensing and 

Related Regulatory Functions”....................................................................... 4-54

4.11.1 Geology and Soils .............................................................................. 4-55

4.11.2 Radionuclides Released to Groundwater............................................ 4-56

4.11.3 Exposure of Aquatic Organisms and Terrestrial Resource to 

Radionuclides..................................................................................... 4-56

4.11.4 Effects on Terrestrial Resources (Non-cooling System Impacts) ........ 4-56

4.11.5 Human Health Impacts From Chemicals and Physical 

Occupational Hazards ........................................................................ 4-57

4.11.6 Environmental Justice ........................................................................ 4-58 

4.11.7 Cumulative Impacts............................................................................ 4-58

4.12 Cumulative Impacts ....................................................................................... 4-58

4.12.1 Land Use............................................................................................ 4-59

4.12.2 Air Quality........................................................................................... 4-59

4.12.3 Water Resources................................................................................ 4-61

4.12.4 Aquatic Resources ............................................................................. 4-65

4.12.5 Terrestrial Resources ......................................................................... 4-69

4.12.6 Human Health .................................................................................... 4-71

4.12.7 Socioeconomics ................................................................................. 4-72

4.12.8 Historic and Archaeological Resources .............................................. 4-74

4.12.9 Summary of Cumulative Impacts........................................................ 4-75

4.13 References .................................................................................................... 4-76

5.0 ENVIRONMENTAL IMPACTS OF POSTULATED ACCIDENTS ................................. 5-1 

5.0 Environmental Impacts of Postulated Accidents .................................................... 5-1 

5.1 Design Basis Accidents.................................................................................... 5-1 

5.2 Severe Accidents............................................................................................. 5-2 

5.3 Severe Accident Mitigation Alternatives ........................................................... 5-3 

5.3.1 Overview of Severe Accident Mitigation Alternative Process ................ 5-3 

5.3.2 Estimate of Risk ................................................................................... 5-3 

5.3.3 Potential Plant Improvements............................................................... 5-8 

5.3.4 Evaluation of Risk Reduction and Costs of Improvements.................... 5-9 

5.3.5 Cost-Benefit Comparison ..................................................................... 5-9 

5.3.6 Conclusions........................................................................................ 5-11

5.4 References .................................................................................................... 5-12
Table of Contents

viii

6.0 ENVIRONMENTAL IMPACTS OF THE URANIUM FUEL CYCLE, WASTE 

MANAGEMENT, AND GREENHOUSE GAS EMISSIONS .......................................... 6-1 

6.1 The Uranium Fuel Cycle .................................................................................. 6-1 

6.2 Greenhouse Gas Emissions ............................................................................ 6-3 

6.2.1 Existing Studies.................................................................................... 6-3 

6.3 References ...................................................................................................... 6-9 

7.0 ENVIRONMENTAL IMPACTS OF DECOMMISSIONING............................................ 7-1 

7.1 Decommissioning............................................................................................. 7-1 

7.2 References ...................................................................................................... 7-2 

8.0 ENVIRONMENTAL IMPACTS OF ALTERNATIVES.................................................... 8-1 

8.1 New Nuclear Generation.................................................................................. 8-4 

8.1.1 Air Quality............................................................................................. 8-5 

8.1.2 Surface Water Resources .................................................................... 8-6 

8.1.3 Groundwater Resources....................................................................... 8-7 

8.1.4 Aquatic Ecology.................................................................................... 8-8 

8.1.5 Terrestrial Ecology ............................................................................... 8-9 

8.1.6 Human Health ...................................................................................... 8-9 

8.1.7 Land Use............................................................................................ 8-10

8.1.8 Socioeconomics ................................................................................. 8-10

8.1.9 Transportation .................................................................................... 8-11

8.1.10 Aesthetics........................................................................................... 8-11

8.1.11 Historic and Archaeological Resources .............................................. 8-12

8.1.12 Environmental Justice ........................................................................ 8-13

8.1.13 Waste Management ........................................................................... 8-14

8.1.14 Summary of Impacts of New Nuclear Generation............................... 8-14

8.2 Natural Gas-Fired Combined-Cycle Generation............................................. 8-14

8.2.1 Air Quality........................................................................................... 8-16

8.2.2 Surface Water Resources .................................................................. 8-18

8.2.3 Groundwater Resources..................................................................... 8-19

8.2.4 Aquatic Ecology.................................................................................. 8-19

8.2.5 Terrestrial Ecology ............................................................................. 8-20

8.2.6 Human Health .................................................................................... 8-21

8.2.7 Land Use............................................................................................ 8-21

8.2.8 Socioeconomics ................................................................................. 8-22

8.2.9 Transportation .................................................................................... 8-22

8.2.10 Aesthetics........................................................................................... 8-23

8.2.11 Historic and Archaeological Resources .............................................. 8-23

8.2.12 Environmental Justice ........................................................................ 8-24

8.2.13 Waste Management ........................................................................... 8-25
Table of Contents

ix

8.2.14 Summary of Impacts for the NGCC Generation Alternative ................ 8-25

8.3 Supercritical Coal-Fired Generation ............................................................... 8-26

8.3.1 Air Quality........................................................................................... 8-28

8.3.2 Surface Water Resources .................................................................. 8-31

8.3.3 Groundwater Resources..................................................................... 8-31

8.3.4 Aquatic Ecology.................................................................................. 8-32

8.3.5 Terrestrial Ecology ............................................................................. 8-33

8.3.6 Human Health .................................................................................... 8-33

8.3.7 Land Use............................................................................................ 8-34

8.3.8 Socioeconomics ................................................................................. 8-35

8.3.9 Transportation .................................................................................... 8-35

8.3.10 Aesthetics........................................................................................... 8-36

8.3.11 Historic and Archaeological Resources .............................................. 8-36

8.3.12 Environmental Justice ........................................................................ 8-37

8.3.13 Waste Management ........................................................................... 8-38

8.3.14 Summary of Impacts for the Supercritical Coal-Fired Generation 

Alternative .......................................................................................... 8-38

8.4 Combination Alternative................................................................................. 8-39

8.4.1 Air Quality........................................................................................... 8-40

8.4.2 Surface Water Resources .................................................................. 8-43

8.4.3 Groundwater Resources..................................................................... 8-44

8.4.4 Aquatic Ecology.................................................................................. 8-44

8.4.5 Terrestrial Ecology ............................................................................. 8-45

8.4.6 Human Health .................................................................................... 8-46

8.4.7 Land Use............................................................................................ 8-46

8.4.8 Socioeconomics ................................................................................. 8-47

8.4.9 Transportation .................................................................................... 8-48

8.4.10 Aesthetics........................................................................................... 8-49

8.4.11 Historic and Archaeological Resources .............................................. 8-49

8.4.12 Environmental Justice ........................................................................ 8-50

8.4.13 Waste Management ........................................................................... 8-51

8.4.14 Summary of Impacts of the Combination Alternative .......................... 8-51

8.5 Purchased Power........................................................................................... 8-52

8.5.1 Air Quality........................................................................................... 8-53

8.5.2 Surface Water and Groundwater Resources ...................................... 8-53

8.5.3 Terrestrial and Aquatic Ecology.......................................................... 8-53

8.5.4 Human Health .................................................................................... 8-54

8.5.5 Land Use............................................................................................ 8-54

8.5.6 Socioeconomics (including transportation and aesthetics).................. 8-54

8.5.7 Historic and Archaeological Resources .............................................. 8-54

8.5.8 Environmental Justice ........................................................................ 8-54
Table of Contents

x 

8.5.9 Waste Management ........................................................................... 8-55

8.5.10 Summary of Impacts of the Purchased Power Alternative ................... 8-55

8.6 Alternatives Considered but Dismissed.......................................................... 8-55

8.6.1 Offsite Nuclear-, Gas-, and Coal-Fired Capacity................................. 8-56

8.6.2 Energy Conservation and Energy Efficiency....................................... 8-56

8.6.3 Wind Power........................................................................................ 8-57

8.6.4 Solar Power........................................................................................ 8-58

8.6.5 Hydroelectric Power ........................................................................... 8-59

8.6.6 Wave and Ocean Energy ................................................................... 8-59

8.6.7 Geothermal Power ............................................................................. 8-59

8.6.8 Municipal Solid Waste ........................................................................ 8-60

8.6.9 Biomass ............................................................................................. 8-61

8.6.10 Biofuels .............................................................................................. 8-61

8.6.11 Oil-Fired Power .................................................................................. 8-62

8.6.12 Fuel Cells ........................................................................................... 8-62

8.6.13 Delayed Retirement............................................................................ 8-62

8.7 No-Action Alternative ..................................................................................... 8-63

8.7.1 Air Quality........................................................................................... 8-63

8.7.2 Surface Water Resources .................................................................. 8-63

8.7.3 Groundwater Resources..................................................................... 8-63

8.7.4 Aquatic Ecology.................................................................................. 8-64

8.7.5 Terrestrial Ecology ............................................................................. 8-64

8.7.6 Human Health .................................................................................... 8-64

8.7.7 Land Use............................................................................................ 8-64

8.7.8 Socioeconomics ................................................................................. 8-64

8.7.9 Transportation .................................................................................... 8-64

8.7.10 Aesthetics and Noise.......................................................................... 8-65

8.7.11 Historic and Archaeological Resources .............................................. 8-65

8.7.12 Environmental Justice ........................................................................ 8-65

8.7.13 Waste Management ........................................................................... 8-65

8.7.14 Summary of Impacts of No-Action Alternative .................................... 8-65

8.8 Alternatives Summary.................................................................................... 8-66

8.9 References .................................................................................................... 8-68

9.0 CONCLUSION ............................................................................................................ 9-1 

9.1 Environmental Impacts of License Renewal..................................................... 9-1 

9.2 Comparison of Alternatives .............................................................................. 9-1 

9.3 Resource Commitments................................................................................... 9-2 

9.3.1 Unavoidable Adverse Environmental Impacts ...................................... 9-2 

9.3.2 Short Term Versus Long Term Productivity .......................................... 9-2 

9.3.3 Irreversible and Irretrievable Commitments of Resources .................... 9-3 
xi

9.4 Recommendations........................................................................................... 9-3 

10.0 LIST OF PREPARERS.............................................................................................. 10-1 

11.0 LIST OF AGENCIES, ORGANIZATIONS, AND PERSONS TO WHOM COPIES

OF THIS SUPPLEMENTAL ENVIRONMENTAL IMPACT STATEMENT ARE 

SENT......................................................................................................................... 11-1 

12.0 INDEX ....................................................................................................................... 12-1 

APPENDIX A. COMMENTS RECEIVED ON THE STP ENVIRONMENTAL REVIEW ............ A-1 

APPENDIX B. NATIONAL ENVIRONMENTAL POLICY ACT ISSUES FOR LICENSE 

RENEWAL OF NUCLEAR POWER PLANTS .................................................. B-1 

APPENDIX C. APPLICABLE REGULATIONS, LAWS, AND AGREEMENTS ......................... C-1 

APPENDIX D. CONSULTATION CORRESPONDENCE ........................................................ D-1 

APPENDIX E. CHRONOLOGY OF ENVIRONMENTAL REVIEW CORRESPONDENCE....... E-1 

APPENDIX F. NRC STAFF EVALUATION OF SEVERE ACCIDENT MITIGATION 

ALTERNATIVES.............................................................................................. F-1 

xiii

Figures

Figure 1–1. Environmental Review Process.......................................................................... 1-2 

Figure 1–2. Environmental Issues Evaluated For License Renewal ...................................... 1-4 

Figure 2–1. Surface Water Bodies and Groundwater Wells in Vicinity of STP 

(STPNOC 2011b)............................................................................................. 2-11

Figure 2–2. The STP Site and 1975 to 1976 Aquatic Ecology Sampling Location 

(NRC 2011b).................................................................................................... 2-27

Figure 2–3. The STP Site and 2007 to 2008 Aquatic Ecology Sampling Locations

from Segment C through the Upstream Portion of Segment B (NRC 

2011b).............................................................................................................. 2-28

Figure 2–4. The STP Site and 2007 to 2008 Aquatic Ecology Sampling Locations 

from the Downstream Portion of Segment B through Segment A (NRC 

2011b).............................................................................................................. 2-29

Figure 2–5. Most Commonly Recorded CBC Species, 2007 through 2011 (Audubon 

2011)................................................................................................................ 2-41

Figure 2–6. STP 50-mi (80-km) Radius Map (STPNOC 2010b) .......................................... 2-45

Figure 2–7. STP 6-mi (10-km) Radius Map (STPNOC 2010b) ............................................ 2-46

Figure 4–1. Species Richness of Aquatic Species Captured in Trawl Surveys from 

1974, 1983, and 2007 through 2008................................................................. 4-23 

Figure 4–2. 2010 Census Minority Block Groups Within a 50-mi Radius of STP ................. 4-49 

Figure 4–3. Census 2010 Low-Income Block Groups Within a 50-mi Radius of STP .......... 4-51

xv 

Tables

Table 2–1. Macroinvertebrates Collected in the Colorado River by Gear Type, 2007 

to 2008............................................................................................................. 2-31

Table 2–2. Fish Collected in the Colorado River by Gear Type, 2007 to 2008 ................... 2-32

Table 2–3. Species Richness (number of species) in Three River Segments by Gear 

Type................................................................................................................. 2-33

Table 2–4. Fish and Invertebrates Collected in the MCR by Gill Nets, Seines, and 

Trawls, 2007 to 2008........................................................................................ 2-35

Table 2–5. Fish and Invertebrates Collected in the MCR by Plankton Tows, 2007 to 

2008................................................................................................................. 2-36

Table 2–6. Birds Observed in High Numbers for One Christmas Count Year, 2007 

through 2011.................................................................................................... 2-40

Table 2–7. Birds Documented on the STP Site, 2007 through 2008 .................................. 2-42

Table 2–8. ESA Species Under NMFS Jurisdiction That Occur in Matagorda County........ 2-48

Table 2–8a. ESA Species Under FWS Jurisdiction That Occur in Matagorda County.......... 2-50

Table 2–8b. TXMM CBC Results for Federally Listed Species, 2008–2012......................... 2-53

Table 2–9. NMFS Species of Concern............................................................................... 2-56

Table 2–10. Ecoregion 5 Species with Designated EFH ...................................................... 2-59

Table 2–11. State-listed Species.......................................................................................... 2-62

Table 2–12. STP, Employee Residence by County.............................................................. 2-64

Table 2–13. Housing in Brazoria and Matagorda Counties in 2010...................................... 2-64

Table 2–14. Brazoria and Matagorda County City Public Water Supply Systems (in 

mgd)................................................................................................................. 2-65

Table 2–15. Major Commuting Routes in the Vicinity of STP, 2010 AADT........................... 2-66

Table 2–16. Population and Percent Growth in Brazoria and Matagorda Counties 

from 1970 to 2010 and Projected for 2020 to 2050........................................... 2-68

Table 2–17. Demographic Profile of the Population in the STP Two-County 

Socioeconomic ROI in 2010............................................................................. 2-68

Table 2–18. Seasonal Housing in Counties Located within 50 mi of STP............................. 2-69

Table 2–19. Migrant Farm Workers and Temporary Farm Labor in Counties Located 

within 50 mi of STP .......................................................................................... 2-70

Table 2–20. Major Industries in Matagorda County.............................................................. 2-71

Table 2–21. Major Industries in ROI..................................................................................... 2-71

Table 2–22. Estimated Income Information for STP ROI...................................................... 2-72

Table 2–23. Comparison of STP Owner Payments with Taxing District Property Tax .......... 2-73

Table 2–24. STP, Units 1 and 2, Owner Payments to Other Taxing Districts in 

Matagorda........................................................................................................ 2-75

Table 3–1. Category 1 Issues Related to Refurbishment ..................................................... 3-1 

Table 3–2. Category 2 Issues Related to Refurbishment ..................................................... 3-2 

Table 4–1. Land Use Issues ................................................................................................ 4-1 

Table 4–2. Air Quality Issues ............................................................................................... 4-2 

Table 4–3. Surface Water Resources Issues ....................................................................... 4-2 
Tables

xvi

Table 4–4. Surface Water Withdrawals and Usage for Calendar Years 2003–2010 

for STP, Units 1 and 2........................................................................................ 4-4 

Table 4–5. Groundwater Resources Issues ......................................................................... 4-5 

Table 4–6. Projected Drawdown and Change in Drawdown in Feet for the Deep 

Chicot Aquifer for Selected Distances ................................................................ 4-7 

Table 4–7. Aquatic Resource Issues.................................................................................. 4-11

Table 4–8. Number (per 100 m3) of Macrozooplankton and Ichthyoplankton 

Collected in Plankton Samples in Front of the RMPF from 1984 and 1985....... 4-14

Table 4–9. Invertebrates and Fish Impinged at the RMPF during 1983–1984 Studies ....... 4-16

Table 4–10. Aquatic Species Collected during Entrainment Sampling in the MCR’s 

CWIS for Units 1 and 2, 2007–2008 ................................................................. 4-17

Table 4–11. Aquatic Species Collected during Impingement Sampling in the MCR’s 

CWIS for Units 1 and 2, 2007–2008 ................................................................. 4-18

Table 4–12. Terrestrial Resources Issues Identified in the GEIS.......................................... 4-27

Table 4–13. Protected Species Issues Identified in the GEIS............................................... 4-28

Table 4–14. ESA Effect Determinations for Federally Listed Species Under NMFS 

Jurisdiction ....................................................................................................... 4-29

Table 4–14a. ESA Effect Determinations for Federally Listed and Candidate Species 

Under NMFS’s Jurisdiction............................................................................... 4-30

Table 4–15. Human Health Issues....................................................................................... 4-34

Table 4–16. Socioeconomics during the Renewal Term ...................................................... 4-41

Table 4–16a. Newly Revised 10 CFR Part 51 Issues............................................................ 4-55

Table 4–17. Summary of Cumulative Impacts on Resource Areas........................................ 4-75

Table 5–1. Issues Related to Postulated Accidents Two issues related to postulated 

accidents are evaluated under the National Environmental Protection Act 

(NEPA) in the license renewal review—DBAs and severe accidents. ................. 5-1 

Table 5–2. STP Core Damage Frequency for Internal Events.............................................. 5-5 

Table 5–3. STP Core Damage Frequency for Fire Events ................................................... 5-6 

Table 5–4. STP Core Damage Frequency for Seismic Events ............................................. 5-6 

Table 5–5. STP Core Damage Frequency for Other External Events................................... 5-7 

Table 5–6. Breakdown of Population Dose by Containment Release Mode......................... 5-8 

Table 5–7. Phase II SAMA List (Cost-Benefit) for STP....................................................... 5-10

Table 6–1. Issues Related to the Uranium Fuel Cycle and Waste Management .................. 6-1 

Table 6–2. Nuclear Greenhouse Gas Emissions Compared to Coal .................................... 6-5 

Table 6–3. Nuclear Greenhouse Gas Emissions Compared to Natural Gas ........................ 6-6 

Table 6–4. Nuclear Greenhouse Gas Emissions Compared to Renewable Energy 

Sources.............................................................................................................. 6-7 

Table 7–1. Issues Related to Decommissioning................................................................... 7-1 

Table 8–1. Expected Annual Emissions from the Largest Stationary Sources of 

Emissions........................................................................................................... 8-6 

Table 8–2. Summary of Environmental Impacts of the New Nuclear Alternative 

Compared to Continued Operation of STP, Units 1 and 2 ................................ 8-14

Table 8–3. Summary of Environmental Impacts of the NGCC Alternative Compared 

to Continued Operation of STP ........................................................................ 8-25
Tables

xvii

Table 8–4. Summary of Environmental Impacts of the Supercritical Coal-Fired 

Alternative Compared to Continued Operation of STP, Units 1 and 2............... 8-38

Table 8–5. Summary of Environmental Impacts of the Combination Alternative 

Compared to Continued Operation of STP, Units 1 and 2 ................................ 8-52

Table 8–6. Summary of Environmental Impacts of the Purchased Power Alternative 

Compared to Continued Operation of STP, Units 1 and 2 ................................ 8-55

Table 8–7. Summary of Environmental Impacts of the No-Action Alternative 

Compared to Continued Operation of STP, Units 1 and 2 ................................ 8-66

Table 8–8. Summary of Environmental Impacts of Proposed Action and Alternatives........ 8-67

Table 10–1. List of Preparers............................................................................................... 10-1 

Table A–1. Individuals Providing Comments During the Scoping Comment Period.............. A-1 

Table A–2. Individuals Providing Comments During the Comment Period.......................... A-20

Table B–1. Summary of Issues and Findings ....................................................................... B-1 

Table C–1. Licenses and Permits......................................................................................... C-1 

Table C–2. Federal, State, and Local Laws and Other Requirements .................................. C-2 

Table D–1. Consultation Correspondence ............................................................................ D-1 

Table E–1. Environmental Review Correspondence............................................................. E-1 

Table F–1. STP Core Damage Frequency for Internal Events.............................................. F-4 

Table F–2. STP Core Damage Frequency for Fire Events ................................................... F-5 

Table F–3. STP Core Damage Frequency for Seismic Events ............................................. F-5 

Table F–4. STP Core Damage Frequency for Other External Events................................... F-6 

Table F–5. Breakdown of Population Dose by Containment Release Mode......................... F-7 

Table F–6. STP PRA Historical Summary ............................................................................ F-9 

Table F–7. SAMA Cost-Benefit Screening Analysis for STP .............................................. F-26

Table F–8. SAMA Cost-Benefit Screening Analysis for STP Using Conservative 

Source Terms................................................................................................... F-31

Table F–9. SAMA Cost-Benefit Screening Analysis for STP Using Updated Fire and 

Seismic Risk Analysis and Conservative Source Terms................................... F-32

xix

EXECUTIVE SUMMARY

BACKGROUND

By letter dated October 25, 2010, STP Nuclear Operating Company (STPNOC) submitted an 

application to the U.S. Nuclear Regulatory Commission (NRC) to issue renewed operating 

licenses for South Texas Project (STP), Units 1 and 2, for an additional 20-year period.

Pursuant to Title 10, Part 51.20(b)(2) of the Code of Federal Regulations (10 CFR 51.20(b)(2)), 

the renewal of a power reactor operating license requires preparation of an environmental 

impact statement (EIS) or a supplement to an existing EIS. In addition, 10 CFR 51.95(c) states 

that the NRC shall prepare an EIS, which is a supplement to the Commission’s NUREG-1437, 

Generic Environmental Impact Statement (GEIS) for License Renewal of Nuclear Plants (GEIS). 

Upon acceptance of STPNOC’s application, the NRC staff began the environmental review 

process described in 10 CFR Part 51 by publishing a notice of intent to prepare a supplemental 

EIS (SEIS) and conduct scoping. In preparation of this SEIS for STP, the NRC staff performed 

the following:

• conducted public scoping meetings on March 2, 2011, in Bay City, Texas;

• conducted a site audit at the plant in July 2011; 

• reviewed STPNOC’s Environmental Report (ER) and compared it to the 

GEIS; 

• consulted with other agencies; 

• conducted a review of the issues following the guidance set forth in 

NUREG-1555, Standard Review Plans for Environmental Reviews for 

Nuclear Power Plants, Supplement 1: Operating License Renewal; and 

• considered public comments received during the scoping process. 

PROPOSED ACTION

STPNOC initiated the proposed Federal action—issuing renewed power reactor operating 

licenses—by submitting an application for license renewal of STP, for which the existing 

licenses (NPF-76 and NPF-80) for STP, Units 1 and 2, will expire on August 20, 2027, and 

December 15, 2028, respectively. The NRC’s Federal action is the decision whether or not to 

renew the licenses for an additional 20 years.

PURPOSE AND NEED FOR ACTION

The purpose and need for the proposed action (issuance of a renewed license) is to provide an 

option that allows for power generation capability beyond the term of the current nuclear power 

plant operating license to meet future system generating needs. Such needs may be 

determined by other energy-planning decisionmakers, such as State, utility, and—where 

authorized—Federal (other than NRC). This definition of purpose and need reflects the NRC’s 

recognition that, unless there are findings in the safety review required by the Atomic Energy 

Act or findings in the National Environmental Policy Act (NEPA) environmental analysis that 

would lead the NRC to reject a license renewal application, the NRC does not have a role in the 
Executive Summary

xx 

energy-planning decisions of whether a particular nuclear power plant should continue to 

operate.

If the renewed license is issued, the appropriate energy-planning decisionmakers, along with 

STPNOC, will ultimately decide if the reactor units will continue to operate based on factors 

such as the need for power. If the operating licenses are not renewed, then the facility must be 

shut down on or before the expiration dates of the current operating licenses—August 20, 2027, 

and December 15, 2028.

ENVIRONMENTAL IMPACTS OF LICENSE RENEWAL

The SEIS evaluates the potential environmental impacts of the proposed action. The 

environmental impacts from the proposed action are designated as SMALL, MODERATE, or 

LARGE. As set forth in the GEIS, Category 1 issues are those that meet all of the following 

criteria:

• The environmental impacts associated with the issue 

is determined to apply either to all plants or, for some 

issues, to plants having a specific type of cooling 

system or other specified plant or site characteristics.

• A single significance level (i.e., SMALL, MODERATE, 

or LARGE) has been assigned to the impacts, except 

for collective offsite radiological impacts from the fuel 

cycle and from high-level waste and spent fuel 

disposal.

• Mitigation of adverse impacts associated with the 

issue is considered in the analysis, and it has been 

determined that additional plant-specific mitigation 

measures are likely not to be sufficiently beneficial to 

warrant implementation.

For Category 1 issues, no additional site-specific analysis is required in this SEIS unless new 

and significant information is identified. Chapter 4 of this report presents the process for 

identifying new and significant information. Site-specific issues (Category 2) are those that do 

not meet one or more of the criterion for Category 1 issues; therefore, an additional site-specific 

review for these non-generic issues is required, and the results are documented in the SEIS. 

On June 20, 2013, the NRC published a final rule (78 FR 37282) revising its environmental 

protection regulation, 10 CFR Part 51, “Environmental protection regulations for domestic 

licensing and related regulatory functions.” The final rule updates the potential environmental 

impacts associated with the renewal of an operating license for a nuclear power reactor for an 

additional 20 years. A revised GEIS, which updates the 1996 GEIS, provides the technical 

basis for the revised rule. The revised GEIS specifically supports the revised list of NEPA 

issues and associated environmental impact findings for license renewal contained in Table B-1 

in Appendix B to Subpart A of the revised 10 CFR Part 51. The final rule consolidates similar 

Category 1 and 2 issues, changes some Category 2 issues into Category 1 issues, and 

consolidates some of those issues with existing Category 1 issues. The revised rule also adds 

new Category 1 and 2 issues. 

The final rule became effective 30 days after publication in the Federal Register. Compliance 

by license renewal applicants is not required until 1 year from the date of publication 

(i.e., license renewal environmental reports submitted later than 1 year after publication must be 

SMALL: Environmental 

effects are not detectable or 

are so minor that they will 

neither destabilize nor 

noticeably alter any important 

attribute of the resource.

MODERATE: Environmental 

effects are sufficient to alter 

noticeably, but not to 

destabilize, important 

attributes of the resource.

LARGE: Environmental 

effects are clearly noticeable 

and are sufficient to 

destabilize important attributes 

of the resource.
Executive Summary

xxi

compliant with the new rule). Nevertheless, under NEPA, the NRC must now consider and 

analyze, in its license renewal SEISs, the potential significant impacts described by the final

rule’s new Category 2 issues and, to the extent there is any new and significant information, the 

potential significant impacts described by the final rule’s new Category 1 issues. 

The NRC staff has reviewed STPNOC’s established process for identifying and evaluating the 

significance of any new and significant information (including the consideration and analysis of 

new issues associated with the recently approved revision to 10 CFR Part 51) on the 

environmental impacts of license renewal of STP. Neither STPNOC nor NRC identified 

information that is both new and significant related to Category 1 issues that would call into 

question the conclusions in the GEIS. This conclusion is supported by NRC’s review of the 

applicant’s ER, other documentation relevant to the applicant’s activities, the public scoping 

process and substantive comments raised, and the findings from the environmental site audit 

conducted by the NRC staff. Further, the NRC staff did not identify any new issues applicable 

to STP that have a significant environmental impact. The NRC staff, therefore, relies upon the 

conclusions of the GEIS for all Category 1 issues applicable to STP.

Table ES–1 summarizes the Category 2 issues applicable to STP, if any, as well as the NRC 

staff’s findings related to those issues. If the NRC staff determined that there were no 

Category 2 issues applicable for a particular resource area, the findings of the GEIS, as 

documented in Appendix B to Subpart A of 10 CFR Part 51, stand.

Table ES–1. NRC Conclusions Relating to Site-Specific Impacts of License Renewal

Resource Area Relevant Category 2 Issues Adverse Impacts

Land Use None SMALL

Air Quality None SMALL

Geology & Soils None SMALL

Surface Water Resources Surface water use conflicts SMALL

Groundwater Resources Groundwater use conflicts

Radionuclides released to groundwater

SMALL

SMALL

Aquatic Resources Entrainment & impingement of fish & shellfish

Heat shock

SMALL

SMALL

Terrestrial Resources Effects on terrestrial resources (non-cooling 

system impacts) SMALL

Protected Species Threatened or endangered species SMALL

Human Health Issues Electromagnetic fields—acute effects (electric 

shock vs. chronic effects) 

Microbiological organisms

SMALL to 

MODERATE

SMALL

Socioeconomics Housing Impacts

Public services (public utilities)

Offsite land use

Public services (public transportation)

SMALL

SMALL

SMALL

SMALL

Historic & archaeological resources SMALL
Executive Summary

xxii

Resource Area Relevant Category 2 Issues Adverse Impacts

 Cumulative Impacts

Air Quality MODERATE

Water Resources SMALL to 

MODERATE

Aquatic Resources MODERATE

Terrestrial Resources MODERATE

Socioeconomics SMALL to LARGE

All Other Evaluated 

Resources SMALL

With respect to environmental justice, the NRC staff has determined that there would be no 

disproportionately high and adverse impacts to these populations from the continued operation 

of STP during the license renewal period. Additionally, the NRC staff has determined that no 

disproportionately high and adverse human health impacts would be expected in special 

pathway receptor populations in the region as a result of subsistence consumption of water, 

local food, fish, and wildlife. 

SEVERE ACCIDENT MITIGATION ALTERNATIVES

Since STPNOC had not previously considered alternatives to reduce the likelihood or potential 

consequences of a variety of highly uncommon, but potentially serious, accidents at STP, 

10 CFR 51.53(c)(3)(ii)(L) requires that STPNOC evaluate severe accident mitigation alternatives 

(SAMAs) in the course of the license renewal review. SAMAs are potential ways to reduce the 

risk or potential impacts of uncommon, but potentially severe accidents, and they may include 

changes to plant components, systems, procedures, and training.

The NRC staff reviewed the ER’s evaluation of potential SAMAs. Based on the staff’s review, 

the NRC staff concluded that none of the potentially cost beneficial SAMAs relate to adequately 

managing the effects of aging during the period of extended operation. Therefore, they need 

not be implemented as part of the license renewal, pursuant to 10 CFR Part 54.

ALTERNATIVES

The NRC staff considered the environmental impacts associated with alternatives to license 

renewal. These alternatives include other methods of power generation and not renewing the 

STP operating licenses (the no-action alternative). Replacement power options considered 

were as follows:

• new nuclear generation,

• natural gas-fired combined-cycle generation (NGCC), 

• supercritical coal-fired generation,

• combination alternative (NGCC, wind, and conservation or efficiency), and

• purchased power (coal, gas, wind, or nuclear). 

The NRC staff initially considered many additional alternatives for analysis as alternatives to 

license renewal of STP; these were later dismissed due to technical, resource availability, or 
Executive Summary

xxiii

commercial limitations that currently exist and that the NRC staff believes are likely to continue 

to exist when the existing STP licenses expire. The no-action alternative by the NRC staff, and 

the effects it would have, were also considered. Where possible, the NRC staff evaluated 

potential environmental impacts for these alternatives located both at the STP site and at some 

other unspecified alternate location. Alternatives considered, but dismissed, were as follows:

• offsite nuclear-, gas-, and coal-fired capacity,

• energy conservation and energy efficiency,

• wind power,

• solar power,

• hydroelectric power,

• wave and ocean energy,

• geothermal power,

• municipal solid waste,

• biomass,

• biofuels,

• oil-fired power,

• fuel cells, and

• delayed retirement.

The NRC staff evaluated each alternative using the same impact areas that were used in 

evaluating impacts from license renewal.

RECOMMENDATION

The staff’s recommendation is that the adverse environmental impacts of license renewal for 

STP are not great enough to deny the option of license renewal for energy-planning 

decisionmakers. This recommendation is based on the following:

• analysis and findings in the GEIS,

• ER submitted by STPNOC,

• consultation with Federal, state, local, and tribal government agencies,

• the NRC staff’s own independent review, and

• consideration of public comments received during the scoping process.

 

xxv 

ABBREVIATIONS AND ACRONYMS

AADT average annual daily traffic

ABWR advanced boiling-water reactor

ac acre

ac-ft acre-foot

ACHP Advisory Council on Historic Preservation

ADAMS Agencywide Documents Access and Management System

AEA Atomic Energy Act of 1954

AEO Annual Energy Outlook

AFW auxiliary feedwater

ALARA as low as is reasonably achievable

AMP aging management program

AOC averted offsite property damage costs

AOSC averted onsite costs

APE area of potential effect

AQCR air quality control region

ASME American Society of Mechanical Engineers

ATWS anticipated transient without scram

BACT best available control technology

BEG Bureau of Economic Geology

BGS below ground surface

BMP best management practice

Bq/l becquerels per liter

BTU British thermal unit

C Celsius

CAA Clean Air Act

CAES compressed air energy storage

CAPS Missouri Census Data Center Circular Area Profiling System

CCW component cooling water

CDF core damage frequency
Abbreviations and Acronyms

xxvi 

CDM control drive mechanism

Ceq carbon equivalent

CET containment event tree

CFR U.S. Code of Federal Regulations

cfs cubic feet per second

CLB current licensing basis

cm centimeter

CO2 carbon dioxide

COE cost of enhancement

COL combined license

Corps U.S. Army Corps of Engineers

CPGCD Coastal Plains Groundwater Conservation District

CWA Clean Water Act

CWIS cooling water intake structure

DBA design-basis accident

dBA decibel A-weighting

DG diesel generator

DMR discharge monitoring report

DOE U.S. Department of Energy

DSEIS draft supplemental environmental impact statement

DSHS Department of State Health Services

DWS drinking water standard

ECP essential cooling pond

ECW essential cooling water

ECWIS essential cooling water intake structure

EFH essential fish habitat

EIA Energy Information Administration

EIS environmental impact statement

ELF extremely low frequency

EMF electromagnetic field

EO Executive Order

EOE Encyclopedia of Earth

EPA U.S. Environmental Protection Agency
Abbreviations and Acronyms

xxvii 

EPCRA Emergency Planning and Community Right-to-Know Act

EPRI Electric Power Research Institute

EPZ emergency planning zone

ER Environmental Report

ERCOT Electric Reliability Council of Texas

ESA Endangered Species Act

ESRP environmental standard review plan

F Fahrenheit

F&O facts and observations

FES final environmental statement

FIP Federal Implementation Plan

FM Farm-to-Market

FR Federal Register

FRN Federal Register Notice

FSAR final safety analysis report

FSEIS final supplemental environmental impact statement

ft foot

ft3 cubic foot

ft/s feet per second

FWS U.S. Fish and Wildlife Service

g gram

gal gallon

GCBO Gulf Coast Bird Observatory

GCC global climate change

GE General Electric

GEA Geothermal Energy Association

GEIS generic environmental impact statement

GHG greenhouse gas

GIWW Gulf Intercoastal Waterway

GL generic letter

GMFMC Gulf of Mexico Fishery Management Council

gpd gallons per day

gpm gallons per minute
Abbreviations and Acronyms

xxviii 

GWMS gaseous waste management system

ha hectare

HAP hazardous air pollutant

HARC Houston Advanced Research Center

hr hour

HVAC heating, ventilation, and air conditioning

Hz hertz

IAEA International Atomic Energy Agency

IEEE Institute of Electrical and Electronics Engineers, Inc.

IES Institute of Educational Sciences

IGCC integrated gasification combined cycle

in. inch

IPA integrated plant assessment

IPCC Intergovernmental Panel on Climate Change

IPE individual plant examination

IPEEE individual plant examination of external events

ISD independent school district

ISEPA Iowa Stored Energy Plant Agency

ISLOCA interfacing system loss-of-coolant accident

kg kilogram

km kilometer

km2 square kilometer

kV kilovolt

kWh kilowatt hour

L/min liters per minute

lb pound

LCRA Lower Colorado River Authority

LCRWPG Lower Colorado River Water Planning Group

LERF large early release frequency

LLNL Lawrence Livermore National Laboratory

LLW low-level waste
Abbreviations and Acronyms

xxix

LOCA loss-of-coolant accident

LOOP loss of offsite power

LRA license renewal application

LWPS liquid waste processing system

m meter

m3 cubic meter

m3/s cubic meters per second

mA milliampere

MAAP Modular Accident Analysis Program

MACCS2 MELCOR Accident Consequence Code System 2

MACR maximum averted cost-risk

MBTA Migratory Bird Treaty Act

MCR main cooling reservoir

MDC main drainage channel

mg/l milligrams per liter

mgd millions of gallons per day

mGy milligray

mi mile

min minute

MIT Massachusetts Institute of Technology

mm millimeter

MMI Modified Mercalli Intensity

MMS U.S. Minerals Management Service

mo month

mrad millirad

mrem millirem

MSA Magnuson-Stevens Fishery Conservation and Management Act

MSL mean sea level

mSv millisievert

MT metric ton

MW megawatt

MWd megawatt day

MWe megawatt electric
Abbreviations and Acronyms

xxx 

MWt megawatt thermal

NAAQS National Ambient Air Quality Standards

NASS National Agriculture Statistics Service

NCES National Center for Education Statistics

NEA Nuclear Energy Agency

NEI Nuclear Energy Institute

NEPA National Environmental Policy Act

NESC National Electrical Safety Code

NETL National Energy Technology Laboratory

NGCC natural gas-fired combined-cycle

NHPA National Historic Preservation Act

NIEHS National Institute of Environmental Health Sciences

NMFS National Marine Fisheries Service

NPCC Northwest Power and Conservation Council

NPDES National Pollutant Discharge Elimination System

NRC U.S. Nuclear Regulatory Commission

NRCS Natural Resources Conservation Service

NREL National Renewable Energy Laboratory

NRHP National Register of Historic Places

NRR Office of Nuclear Reactor Regulation

NWS National Weather Service

OECD Organization for Economic Co-operation and Development

OMB Office of Management and Budget

OPSB Ohio Power and Siting Board

PACR potential averted cost-risk

pCi/L picocuries per liter

PDP positive displacement pump

PGA peak ground acceleration

PM10 particulate matter, ≤10 μm

PM2.5 particulate matter, ≤2.5 μm

PNNL Pacific Northwest National Laboratory

POST Parliamentary Office of Science and Technology
Abbreviations and Acronyms

xxxi 

PRA probabilistic risk assessment

PSD prevention of significant deterioration

PWR pressurized-water reactor

RAI request for additional information

RCB reactor containment building

RCP reactor coolant pump

RCRA Resources Conservation and Recovery Act

RCS reactor coolant system

rem roentgen equivalent man

REMP Radiological Environmental Monitoring Program

RG regulatory guide

RMPF reservoir makeup pumping facility

RMTS risk managed technical specification

ROI region of influence

ROW right-of-way

RPC replacement power costs

RRW risk reduction worth

RTC Report to Congress

SAMA severe accident mitigation alternative

SAR safety analysis report

SAWS San Antonio Water System

SBDG standby diesel generator

SCR selective catalytic reduction

SEIS supplemental environmental impact statement

SER safety evaluation report

SG steam generator

SGTR steam generator tube rupture

SHPO State Historic Preservation Office

SIP State Implementation Plan

SNL Sandia National Laboratory

SOARCA State-of-the-Art Reactor Consequence Analysis

SPDES State Pollutant Discharge Elimination System

SSC system, structure, and component
Abbreviations and Acronyms

xxxii 

SSE safe shutdown earthquake

STP South Texas Project

STPNOC South Texas Project Nuclear Operating Company

Sv sievert

SWPS solid waste processing system

TAC Texas Administrative Code

TCEQ Texas Commission on Environmental Quality

TCPA Texas Comptroller of Public Accounts

TDS total dissolved solids

THC Texas Historical Commission

TMMSN Texas Marine Mammal Stranding Network

TPDES Texas Pollutant Discharge Elimination System

TPWD Texas Parks and Wildlife Department

tpy tons per year

TS technical specification

TSC Technical Support Center

TSECO Texas State Energy Conservation Office

TSHA Texas State Historical Association

TSP total suspended particles

TSWGW Texas Saltwater and Fishing Guides Web

TWDB Texas Water Development Board

USCB U.S. Census Bureau

USGS U.S. Geological Survey

VOC volatile organic compound

WEG Wild Earth Guardians

WMA Wildlife Management Area

WOE weight-of-evidence

WSEC White Stallion Energy Center

yr year
1-1 

1.0 PURPOSE AND NEED FOR ACTION

Under the U.S. Nuclear Regulatory Commission’s (NRC’s) environmental protection regulations 

in Title 10, Part 51, of the Code of Federal Regulations (10 CFR 51)—which implement the 

National Environmental Policy Act (NEPA)—issuance of a new nuclear power plant operating 

license requires the preparation of an environmental impact statement (EIS).

The Atomic Energy Act of 1954 (AEA) specifies that licenses for commercial power reactors can 

be granted for up to 40 years. NRC regulations (10 CFR 54.31) allow for an option to renew a 

license for up to an additional 20 years. The initial 40-year licensing period was based on 

economic and antitrust considerations rather than on technical limitations of the nuclear facility.

The decision to seek a license renewal rests entirely with nuclear power facility owners and, 

typically, is based on the facility’s economic viability and the investment necessary to continue 

to meet NRC safety and environmental requirements. The NRC makes the decision to grant or 

deny license renewal based on whether the applicant has demonstrated that the environmental 

and safety requirements in the agency’s regulations can be met during the period of extended 

operation.

1.1 Proposed Federal Action

STP Nuclear Operating Company (STPNOC) initiated the proposed Federal action by 

submitting an application for license renewal of South Texas Project (STP), Units 1 and 2, for 

which the existing licenses (NPF-76 and NPF-80) expire on August 20, 2027, and 

December 15, 2028, respectively. The NRC’s Federal proposed action is the decision whether 

to renew the licenses for an additional 20 years.

1.2 Purpose and Need for the Proposed Federal Action

The purpose and need for the proposed action (issuance of a renewed license) is to provide an 

option that allows for power generation capability beyond the term of a current nuclear power 

plant operating license to meet future system generating needs, as such needs may be 

determined by other energy-planning decisionmakers. This definition of purpose and need 

reflects the NRC’s recognition that, unless there are findings in the safety review required by the 

AEA or findings in the NEPA environmental analysis that would lead the NRC to reject a license 

renewal application (LRA), the NRC does not have a role in the energy-planning decisions of 

State regulators and utility officials as to whether a particular nuclear power plant should 

continue to operate.

If the renewed license is issued, State regulatory agencies and STPNOC will ultimately decide 

whether the plant will continue to operate based on factors such as the need for power or other 

matters within the State’s jurisdiction or the purview of the owners. If the operating license is 

not renewed, then the facility must be shut down on or before the expiration dates of the current 

operating licenses—August 20, 2027, and December 15, 2028, respectively. 

1.3 Major Environmental Review Milestones

STPNOC submitted an Environmental Report (ER) (STPNOC 2010b) as part of its LRA

(STPNOC 2010a) in October 2010. After reviewing the LRA and ER for sufficiency, the NRC 

staff published a Federal Register Notice of Acceptability and Opportunity for Hearing 
1-2 

(76 FRN 2426) on January 13, 2011. Then, on January 31, 2011, the NRC published another 

notice in the Federal Register (76 FR 5410) on the intent to conduct scoping, thereby beginning 

the 60-day scoping period.

The NRC staff held two public scoping meetings on March 2, 2011, in Bay City, Texas. The 

comments received during the scoping process are presented in their entirety in “Environmental 

Impact Statement Scoping Process, Summary Report, South Texas Project, Units 1 and 2, Bay 

City,” published in 2012 (NRC 2012a). The staff presents comments considered to be within the 

scope of the environmental license renewal review and the NRC responses in Appendix A of 

this supplemental environmental impact statement (SEIS). 

In order to independently verify information provided in the ER, the NRC staff conducted a site 

audit at STP, Units 1 and 2, in July 2011. During the site audit, the staff met with plant 

personnel, reviewed specific documentation, toured the facility, and met with interested Federal, 

State, and local agencies. A summary of that site audit and the attendees is contained in the 

Audit Summary Report, published in August 2011 (NRC 2011). 

Upon completion of the scoping period and site audit, the NRC staff compiled its findings in the 

draft SEIS (Figure 1–1). This document is made available for public comment for 45 days. 

During this time, the staff would host public meetings and collect public comments. Based on 

the information gathered, it would amend the draft SEIS findings, as necessary, and publish the 

final SEIS for license renewal. 

Figure 1–1. Environmental Review Process

The NRC has established a license renewal review process that can be completed in a 

reasonable period with clear requirements to assure safe plant operation for up to an additional 

20 years of plant life. The NRC staff conducts the safety review simultaneously with the 

environmental review. The staff documents the findings of the safety review in a safety 
1-3 

evaluation report (SER). The findings in the SEIS and the SER are both factors in the NRC’s 

decision to either grant or deny the issuance of a renewed license. 

1.4 Generic Environmental Impact Statement

The NRC staff performed a generic assessment of the environmental impacts associated with 

license renewal to improve the efficiency of its license renewal review. The Generic 

Environmental Impact Statement for License Renewal of Nuclear Power Plants (GEIS), 

NUREG-1437 (NRC 1996, 1999), documented the results of the staff’s systematic approach to 

evaluate the environmental consequences of renewing the licenses of individual nuclear power 

plants and operating them for an additional 20 years. The staff analyzed in detail and resolved 

those environmental issues that could be resolved generically in the GEIS.

The GEIS establishes 92 separate issues for the NRC staff to independently verify. Of these 

issues, the NRC staff determined that 69 are generic to all plants (Category 1) while 21 issues 

do not lend themselves to generic consideration (Category 2). Two other issues remain 

uncategorized (environmental justice and chronic effects of electromagnetic fields). The staff 

evaluated these issues on a site-specific basis (along with the Category 2 issues). Appendix B 

provides the list of all 92 issues.

For each potential environmental issue, in the GEIS, the NRC staff performs the following: 

• describes the activity that affects the environment, 

• identifies the population or resource that is affected, 

• assesses the nature and magnitude of the impact on the affected population 

or resource, 

• characterizes the significance of the effect for both beneficial and adverse 

effects, 

• determines whether the results of the analysis apply to all plants, and

• considers whether additional mitigation measures would be warranted for 

impacts that would have the same significance level for all plants. 

The NRC’s standard of significance for impacts was established using the Council on 

Environmental Quality (CEQ) terminology for “significant.” The NRC established three levels of 

significance for potential impacts—SMALL, MODERATE, and LARGE, as defined below.

SMALL: Environmental effects are not 

detectable or are so minor that they will neither 

destabilize nor noticeably alter any important 

attribute of the resource.

MODERATE: Environmental effects are 

sufficient to alter noticeably, but not to destabilize, 

important attributes of the resource.

LARGE: Environmental effects are clearly noticeable and are sufficient to destabilize important 

attributes of the resource.

The GEIS includes a determination of whether the analysis of the environmental issue could be 

applied to all plants and whether additional mitigation measures would be warranted 

(Figure 1–2). Issues are assigned a Category 1 or a Category 2 designation. As set forth in the 

GEIS, Category 1 issues are those that meet the following criteria:

Significance indicates the importance of likely 

environmental impacts and is determined by 

considering two variables: context and intensity. 

Context is the geographic, biophysical, and social 

context in which the effects will occur. 

Intensity refers to the severity of the impact, in 

whatever context it occurs.
1-4 

• The environmental impacts associated with the issue have been determined 

to apply either to all plants or, for some issues, to plants having a specific 

type of cooling system or other specified plant or site characteristics.

• A single significance level (i.e., SMALL, MODERATE, or LARGE) has been 

assigned to the impacts (except for collective offsite radiological impacts from 

the fuel cycle and from high-level waste and spent fuel disposal).

• Mitigation of adverse impacts associated with the issue has been considered 

in the analysis, and it has been determined that additional plant-specific 

mitigation measures are likely not to be sufficiently beneficial to warrant 

implementation.

Figure 1–2. Environmental Issues Evaluated For License Renewal

In the GEIS, 92 issues were evaluated. 

A site-specific analysis is required for 23 of those 92 issues

On June 20, 2013, the NRC published a final rule (78 FR 37282) revising its environmental 

protection regulation, 10 CFR Part 51, “Environmental protection regulations for domestic 

licensing and related regulatory functions.” 
1-5 

Specifically, the final rule updates the potential environmental impacts associated with the 

renewal of an operating license for a nuclear power reactor for an additional 20 years. A 

revised GEIS (NRC 2013), which updates the 1996 GEIS, provides the technical basis for the 

final rule. The revised GEIS specifically supports the revised list of NEPA issues and 

associated environmental impact findings for license renewal contained in Table B-1 in 

Appendix B to Subpart A of the revised 10 CFR Part 51. The revised GEIS and final rule reflect 

lessons learned and knowledge gained during previous license renewal environmental reviews. 

In addition, public comments received on the draft revised GEIS and rule and during previous 

license renewal environmental reviews were re-examined to validate existing environmental 

issues and identify new ones. 

The final rule identifies 78 environmental impact issues, of which 17 will require plant-specific 

analysis. The final rule consolidates similar Category 1 and 2 issues, changes some 

Category 2 issues into Category 1 issues, and consolidates some of those issues with existing 

Category 1 issues. The final rule also adds new Category 1 and 2 issues. The new Category 1 

issues include geology and soils, exposure of terrestrial organisms to radionuclides, exposure of 

aquatic organisms to radionuclides, human health impact from chemicals, and physical 

occupational hazards. Radionuclides released to groundwater, effects on terrestrial resources 

(non-cooling system impacts), minority and low-income populations (i.e., environmental justice), 

and cumulative impacts were added as new Category 2 issues.

The final rule became effective 30 days after publication in the Federal Register. Compliance 

by license renewal applicants is not required until 1 year from the date of publication 

(i.e., license renewal environmental reports submitted later than 1 year after publication must be 

compliant with the new rule). Nevertheless, under NEPA, the NRC must now consider and 

analyze, in its license renewal SEISs, the potential significant impacts described by the final

rule’s new Category 2 issues and, to the extent there is any new and significant information, the 

potential significant impacts described by the final rule’s new Category 1 issues. 

1.5 Supplemental Environmental Impact Statement

The SEIS presents an analysis that considers the environmental effects of the continued 

operation of STP, Units 1 and 2, alternatives to license renewal, and mitigation measures for 

minimizing adverse environmental impacts. Chapter 8 contains analysis and comparison of the 

potential environmental impacts from alternatives while Chapter 9 presents the recommendation 

of the NRC (the Commission) on whether or not the environmental impacts of license renewal 

are so great that preserving the option of license renewal would be unreasonable. The final 

recommendation will be made after consideration of comments received on the draft SEIS 

during the public comment period. 

In the preparation of this SEIS for STP, Units 1 and 2, the NRC staff carried out the following 

activities: 

• reviewed the information provided in the STPNOC’s ER; 

• consulted with other Federal, State, local agencies, and tribal nations; 

• conducted an independent review of the issues during site audit; and

• considered the public comments received for the review (during the scoping 

process and, subsequently, on the draft SEIS).
1-6 

New information can be identified from many 

sources, including the applicant, the NRC, other 

agencies, or public comments. If a new issue is 

revealed, it is first analyzed to determine whether 

it is within the scope of the license renewal 

environmental evaluation. If the new issue is not 

addressed in the GEIS, the NRC staff would 

determine the significance of the issue and document the analysis in the SEIS.

1.6 Cooperating Agencies

During the scoping process, no Federal, State, or local agencies were identified as cooperating 

agencies in the preparation of this SEIS.

1.7 Consultations

The Endangered Species Act of 1973, as amended; the Magnuson–Stevens Fisheries 

Management Act of 1996, as amended; and the National Historic Preservation Act of 1966 

require that Federal agencies consult with applicable State and Federal agencies and groups 

prior to taking action that may affect endangered species, fisheries, or historic and 

archaeological resources, respectively. The NRC consulted with the following agencies and 

groups (Appendix D to this SEIS includes copies of consultation documents): 

• Advisory Council on Historic Preservation (ACHP), 

• National Marine Fisheries Service (NMFS), 

• State Historic Preservation Office (SHPO), 

• U.S. Fish and Wildlife Service (FWS), 

• Ysleta del Sur Pueblo, 

• Alabama-Coushatta Tribe, 

• Kiowa Tribe of Oklahoma, 

• Comanche Nation, 

• Tonkawa Tribe of Oklahoma, 

• Apalachicola Creek, 

• Lipan Apache Tribe of Texas, 

• Lipan Apache Band of Texas, 

• Tap Pulam-Coahuiltecan Nation, 

• Kickapoo Traditional Council, 

• Pamaque Clan of Coahuila Y Tejas, and 

• Apalachicola Band of Creek Indians. 

New and significant information either identifies 

a significant environmental issue that was not 

covered in the GEIS or was not considered in the 

analysis in the GEIS and leads to an impact 

finding that is different from the finding presented 

in the GEIS.
1-7 

1.8 Correspondence

During the course of the environmental review, the NRC staff contacted Federal, State, regional, 

local, and tribal agencies listed in Section 1.7. Appendix E contains a chronological list of all 

documents sent and received during the environmental review.

In addition, Chapter 11 provides a list of persons who requested and received a copy of this 

SEIS. 

1.9 Status of Compliance

STPNOC is responsible for complying with all NRC regulations and other applicable Federal, 

State, and local requirements. Appendix H of the GEIS describes some of the major applicable 

Federal statutes. 

There are numerous permits and licenses issued by Federal, State, and local authorities for 

activities at STP, Units 1 and 2. Appendix C contains further discussion by the staff about 

status of compliance. Regarding Coastal Zone Management Act (CZMA) compliance status, 

pursuant to Section 506.11(13) of Texas Administrative Code, STPNOC has obtained and 

maintained satisfactorily a consistency certification in accordance with the CZMA (Section 2.3 

contains further discussion about CZMA compliance status for STP license renewal). 

1.10 References

10 CFR 51. Code of Federal Regulations, Title 10, Energy, Part 51, “Environmental protection 

regulations for domestic licensing and related regulatory functions.”

10 CFR 54. Code of Federal Regulations, Title 10, Energy, Part 54, “Requirements for renewal 

of operating licenses for nuclear power plants.”

76 FR 2426. U.S. Nuclear Regulatory Commission. “Notice of Acceptance for Docketing of the 

Application and Notice of Opportunity for Hearing Regarding Renewal of Facility Operating 

License Numbers NPF–76 and NPF–80 for an Additional 20-Year Period, STP Nuclear 

Operating Company, South Texas Project, Units 1 and 2.” Federal Register. Volume 76(9): 

2426–2428. January 13, 2011.

76 FRN 5410. U.S. Nuclear Regulatory Commission. “STP Nuclear Operating Company; 

Notice of Intent To Prepare an Environmental Impact Statement and Conduct the Scoping 

Process for South Texas Project, Units 1 and 2.” Federal Register. Volume 76(20): 

5410–5411. January 31, 2011.

78 FR 37282. U.S. Nuclear Regulatory Commission. “Revisions to Environmental Review for 

Renewal of Nuclear Power Plant Operating Licenses.” June 20, 2013. 

[AEA] Atomic Energy Act of 1954, as amended. 42 U.S.C. §2011, et seq.

Endangered Species Act of 1973, as amended. 16 U.S.C. §1531, et seq.

Magnuson–Stevens Fishery Conservation and Management Act, as amended. 

16 U.S.C. §1801 et seq.

[NEPA] National Environmental Policy Act of 1969, as amended. 42 U.S.C. §4321, et seq.

National Historic Preservation Act of 1966. 16 U.S.C. §470, et seq.
1-8 

[NRC] U.S. Nuclear Regulatory Commission. 1996. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. Washington, DC: NRC. NUREG-1437. May 1996. 

ADAMS Nos. ML040690705 and ML040690738.

[NRC] U.S. Nuclear Regulatory Commission. 1999. Section 6.3, Transportation, Table 9.1, 

Summary of findings on NEPA issues for license renewal of nuclear power plants. In: Generic

Environmental Impact Statement for License Renewal of Nuclear Plants. Washington, DC: 

NRC. NUREG-1437, Volume 1, Addendum 1. August 1999. ADAMS No. ML040690720.

[NRC] U.S. Nuclear Regulatory Commission. 2011. Summary of site audit related to the 

review of the license renewal application for South Texas Project, Units 1 and 2. 

August 4, 2011. ADAMS No. ML11196A005.

[NRC] U.S. Nuclear Regulatory Commission. 2012a. Environmental Impact Statement 

Scoping Process, Summary Report, South Texas Project, Units 1 and 2, Bay City, TX. 

Washington, DC: NRC. 2012. ADAMS No. ML11153A082. 

[NRC] U.S. Nuclear Regulatory Commission. 2013. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. Washington, DC: Office of Nuclear Reactor Regulation. 

NUREG-1437, Revision 1, Volumes 1, 2, and 3. June 2013. ADAMS Nos. ML13106A241, 

ML13106A242, and ML13106A244. 

[STPNOC] South Texas Plant Nuclear Operating Company. 2010a. “South Texas Project, 

Units 1 and 2, Docket Nos. STN 50–498, STN 50–499, License Renewal Application.” 

October 25, 2010. ADAMS No. ML103010257.

[STPNOC] South Texas Plant Nuclear Operating Company. 2010b. “South Texas Project, 

Applicant’s Environmental Report—Operating License Renewal Stage, South Texas Project 

Units 1 & 2.” September 2010. ADAMS No. ML103010263.
2-1 

2-1 

2.0 AFFECTED ENVIRONMENT

South Texas Project (STP) is located in Matagorda County, Texas, approximately 70 mi

(110 km) south-southwest of Houston. The plant consists of two reactor units. Each nuclear 

reactor is a pressurized-water reactor (PWR) with steam generators producing steam that turns 

turbines to generate electricity. For purposes of the evaluation in this report, the “affected 

environment” is the environment that currently exists at and around STP. Because existing 

conditions are at least partially the result of past construction and operation at the plant, the 

impacts of these past and ongoing actions and how they have shaped the environment are 

presented here. The facility and its operation are described in Section 2.1, and the affected 

environment is presented in Section 2.2.

2.1 Facility Description

STP is a two-unit, nuclear-powered steam electric generating facility that began commercial 

operation in August 1988 (Unit 1) and June 1989 (Unit 2). The nuclear reactor for each unit is a 

Westinghouse PWR, producing a reactor core rated thermal power of 3,853 megawatts-thermal 

(MWt). The nominal net electrical capacity is 1,250 megawatts-electric (MWe). In this 

supplemental environmental impact statement (SEIS), the use of “STP” is referring to the site 

where the existing “STP, Units 1 and 2” are located. The use of “STPNOC” is referring to the 

applicant (STP Nuclear Operating Company) who submitted the license renewal application

(LRA). The use of “STP, Units 1 and 2” is referring to the distinction between the existing 

reactor units and the proposed new reactor units, “STP, Units 3 and 4.” 

2.1.1 Reactor and Containment Systems

The nuclear steam supply system at STP is a four-loop Westinghouse PWR. The reactor core 

heats water, which is pumped to four steam generators where the heat boils the water on the 

shell-side into steam that is routed to the turbines. The steam turns the turbines, which are 

connected to the electrical generator. The Units 1 and 2 steam generators were replaced in 

2000 and 2002, respectively, with new Westinghouse steam generators.

The nuclear fuel is low-enriched uranium dioxide with enrichments less than 5 percent by weight 

uranium-235 and fuel burnup levels with a batch average of approximately 

45,000 megawattdays (MWd) per metric ton uranium at discharge. Maximum burnup would not 

exceed 60,000 MWd per metric ton uranium. STP operates on an 18-month refueling cycle.

The reactor, steam generators, and related systems are enclosed in a containment building. 

The containment building is a post-tensioned, reinforced concrete cylinder with a slab base and 

a hemispherical dome. A welded steel liner is attached to the inside face of the concrete shell 

to ensure a high degree of leak tightness. In addition, the 4-ft (1.2-m)–thick concrete walls 

serve as a radiation shield.

2.1.2 Radioactive Waste Management

STP uses liquid, gaseous, and solid waste 

processing systems to collect and treat, as 

needed, radioactive materials that are produced 

as by-products of plant operations. These 

materials are produced in the form of 

By design, the operation of nuclear power plants 

is expected to result in small releases of 

radiological effluents (gaseous, liquid, and solid) 

through controlled processes. However, releases 

must meet stringent NRC and EPA regulatory 

limits.
Affected Environment

2-2 

(a) activation products resulting from irradiation of reactor water and impurities, principally 

metallic corrosive products, therein and (b) fission products resulting from their migration 

through the fuel cladding. Radioactive materials in liquid and gaseous effluents (controlled 

releases from STP) are reduced to levels that ensure compliance with U.S. Nuclear Regulatory 

Commission (NRC) radiation protection regulations in Title 10, Part 20, of the U.S. Code of 

Federal Regulations (10 CFR Part 20), and they are as low as is reasonably achievable 

(ALARA), in accordance with Appendix I to 10 CFR Part 50.

Reactor fuel assemblies that have exhausted some of their fissile uranium content (related to 

the ability to sustain nuclear criticality chain reaction) are referred to as spent fuel (or used fuel). 

Spent fuel assemblies are removed from the reactor core and replaced by new fuel assemblies 

during routine refueling outages, typically every 18 months. The spent fuel assemblies are then 

stored in the spent fuel pool.

Systems used at STP to process radioactive liquid, gaseous, and solid wastes are described in 

the following sections.

2.1.2.1 Radioactive Gaseous Waste System

The objectives of the gaseous waste management system (GWMS) are to process and control 

the release of radioactive gaseous effluents into the environment to be within the requirements 

of 10 CFR Part 20 and to be consistent with the ALARA guidelines set forth in Appendix I to 

10 CFR Part 50. The GWMS also removes fission product gases from the reactor coolant 

system and from equipment and piping (i.e., reduces the amount of radioactivity from the gases

before they are released into the environment). The GWMS is designed so that radiation 

exposure to plant workers is within NRC dose limits in 10 CFR 20.1201 and ALARA.

The GWMS processes the waste gas to control and limit the amount of radioactive noble gas 

and iodine released into the environment. An inlet header water removal system removes water 

vapor and heat from the gas stream prior to processing the gas through charcoal beds. The 

charcoal beds are designed to delay the passage of the gases, which allows for radioactive 

decay of the noble gases and adsorption of radioiodine as the gas stream moves through the 

charcoal beds. At the end of the charcoal bed, the gas is filtered by high efficiency filters to 

remove charcoal dust. There is also a radiation monitor that measures the radioactivity in the 

waste gas and can automatically terminate the release in the event radioactivity exceeds 

predetermined levels.

The primary sources of radioactive gas in the plant are as follows: 

• the turbine generator building process vents, 

• the auxiliary feedwater pump turbine exhaust, which is vented directly to the 

atmosphere through the isolation valve cubicle process vent, 

• the reactor containment building ventilation system, 

• the mechanical auxiliary building, 

• the fuel handling building ventilation system, and

• the reactor coolant gases.

2.1.2.2 Radioactive Liquid Waste System

The function of STPNOC’s liquid waste processing system (LWPS) is to collect and process 

radioactive liquid wastes to reduce radioactivity and chemical concentrations to levels 

acceptable for discharge to the environment or to recycle the liquids for use in plant systems.
Affected Environment

2-3 

The principal objectives of the LWPS are to collect liquid wastes that may contain radioactive 

material and to maintain sufficient processing capability so that liquid waste may be discharged 

to the environment below the regulatory limits of 10 CFR Part 20 and consistent with the 

ALARA guidelines in Appendix I to 10 CFR Part 50.

Sources of liquid waste sent to the LWPS include floor drains, equipment drains, laundry and 

hot shower drains, and contaminated wastes from plant systems and components. Processing 

of the liquid waste is performed using several different methods including filtration, 

demineralization, evaporation, or a combination of the three methods.

Liquid releases from the plant are made in accordance with NRC radiation protection standards 

in 10 CFR Part 20 and the ALARA guidelines set forth in Appendix I to 10 CFR Part 50. The 

waste is routed through a monitor that measures the radioactivity and can automatically 

terminate the release in the event radioactivity exceeds predetermined levels. The liquid waste 

is discharged into the main cooling reservoir (MCR). The entire MCR is within the STP site 

boundary, and the public is prohibited from access to the MCR.

2.1.2.3 Radioactive Solid Waste Processing Systems

The solid waste processing system (SWPS) is designed to process, package, and store the 

solid radioactive wastes generated by plant operations until they are shipped off site to a vendor 

for further processing or for permanent disposal at a licensed burial facility or both. The SWPS 

is designed to meet the following objectives:

• to collect process, package, temporary store, and prepare the waste for 

shipment; 

• to maintain radiation exposes to plant personnel within the dose limits of 

10 CFR Part 20.1201 and ALARA; 

• to package and transport the waste in compliance with NRC regulations 

10 CFR Parts 61 and 71 and the U.S. Department of Transportation

regulations 49 CFR Parts 170 through 179; and

• to stabilize wet waste using either an onsite or offsite system from a qualified 

vendor.

The permanently installed portion of the SWPS is located within the mechanical-electrical 

auxiliary building. Identical systems containing the following major subsystems are used for 

STP, Units 1 and 2: 

• Concentrate storage tank and transfer subsystem—This subsystem includes 

a 5,000-gallon storage tank equipped with a mixer, heat tracing, and level 

controls to prevent overflows. The applicant states that this system is 

currently not in use.

• Spent resin transfer subsystem—This system is used to transfer spent resin 

filter media to a vendor-supplied processing system.

• Expended cartridge filter transfer subsystem—This system handles filter 

cartridges used to process radioactive liquid wastes. The system uses

shielding and long-handled tools to safely handle the filters for insertion into a 

shielded cask that will be transported to a disposal facility.

• Overhead crane subsystem—This is a remotely operated 7 1⁄2-ton overhead 

bridge crane with automatic grapples to move loaded containers from the 
Affected Environment

2-4 

storage areas to the truck loading area and to stabilize wet waste using either 

an onsite or offsite system from a qualified vendor.

• Dry active waste area—This area is used to sort and package dry active 

waste. The waste is typically sent to an offsite vendor for volume reduction 

prior to disposal.

• Chemical addition subsystem—This subsystem provides chemical 

adjustment of liquids to maintain pH control for efficient processing.

• Vendor-supplied onsite subsystem—This subsystem consists of control 

panels used to control dewatering pumps, fill and dewatering heads, level 

controls, and monitoring instruments.

Radioactive waste is stored within plant buildings until it is shipped off site for further processing 

by a vendor or disposal or both. The storage areas have restricted access and shielding to 

reduce radiation rates to plant workers. The radioactive waste is divided into high activity and 

low activity storage areas. Separation of the high activity storage area from the building exterior 

by the low activity area provides for a reduction in radiation levels to plant workers in the truck 

loading area.

The Texas Low-Level Radioactive Waste Disposal Compact Facility, located in Andrews 

County, Texas, opened on November 10, 2011. The facility is licensed by the State of Texas to 

dispose of Class A, B, and C low-level waste (LLW). This LLW disposal facility is available to 

STP for the disposal of its LLW. With the availability of this disposal facility, the current LLW 

handling and storage facilities are expected to be adequate to handle LLW waste generated 

during the license renewal term.

In the event of an interruption in LLW disposal capability, STP has the ability to store its waste 

on site. STP has an onsite staging facility, located west of STP Unit 2. This facility can provide 

a staging area for the waste for up to 5 years of operation of both reactor units.

2.1.3 Nonradiological Waste Management

STP generates nonradioactive wastes as part of routine plant maintenance, cleaning activities, 

and plant operations. In general, Resources Conservation and Recovery Act (RCRA) waste 

regulations governing the disposal of solid and hazardous waste are contained in 

40 CFR Parts 239 through 299. Specifically, 40 CFR Parts 239 through 259 contain regulations 

for solid (nonhazardous) waste, and 40 CFR Parts 260 through 279 contain regulations for 

hazardous waste. RCRA, Subtitle C, establishes a system for controlling hazardous waste from 

“cradle to grave,” and RCRA, Subtitle D, encourages states to develop comprehensive plans to 

manage nonhazardous solid waste and mandates minimum technological standards for 

municipal solid waste landfills. Texas State RCRA regulations are administered by the Texas 

Commission on Environmental Quality (TCEQ) and address the identification, generation, 

minimization, transportation, and final treatment, storage, or disposal of hazardous and 

nonhazardous waste.

2.1.3.1 Nonradioactive Waste Streams

STP generates solid waste, defined by the RCRA, as part of routine plant maintenance, 

cleaning activities, and plant operations. Texas administers the RCRA Program in Texas 

Administrative Code (TAC) 335.

The U.S. Environmental Protection Agency (EPA) classifies certain nonradioactive wastes as 

hazardous based on characteristics including ignitability, corrosivity, reactivity, or toxicity 

(hazardous wastes are listed in 40 CFR Part 261). State-level regulators may add wastes to 
Affected Environment

2-5 

EPA’s list of hazardous wastes. RCRA supplies standards for the treatment, storage, and 

disposal of hazardous waste for hazardous waste generators (regulations are available in 

40 CFR Part 262).

EPA recognizes the following main types of the hazardous waste generators (40 CFR 260.10) 

based on the quantity of the hazardous waste produced:

• large quantity generators that generate 2,200 lb (1,000 kg) per month or more 

of hazardous waste, more than 2.2 lb (1 kg) per month of acutely hazardous 

waste, or more than 220 lb (100 kg) per month of acute spill residue or soil; 

• small quantity generators that generate more than 220 lb (100 kg) but less 

than 2,200 lb (1,000 kg) of hazardous waste per month; and

• conditionally exempt small quantity generators that generate 220 lb (100 kg) 

or less per month of hazardous waste, 2.2 lb (1 kg) or less per month of 

acutely hazardous waste, or less than 220 lb (100 kg) per month of acute spill 

residue or soil.

TCEQ recognizes STP as a small quantity generator of hazardous wastes under TAC 335. STP 

hazardous wastes include waste oil, grease, electrohydraulic fluid, adhesives, liquid paint, and 

solvent for fuel blending and thermal energy recovery. Used oil diesel fuels and used oil filters 

are sent to a recycling vendor for re-processing. Lead-acid batteries are returned, when 

possible, to the original manufacturer for recycling or are shipped to a registered battery 

recycler. 

EPA classifies several hazardous wastes as universal wastes; these include batteries, 

pesticides, mercury-containing items, and fluorescent lamps. TCEQ has incorporated EPA’s 

regulations (40 CFR Part 273) regarding universal wastes in TAC 335.261. Universal wastes 

produced by STP are disposed of or recycled in accordance with TCEQ regulations.

Conditions and limitations for wastewater discharge by STP are specified in Texas Pollution 

Discharge Elimination System (TPDES) Permit No. WQ0001908000. In 2009, STP applied for 

a renewal of this wastewater discharge permit and, at the writing of this SEIS, continues to work 

with TCEQ on its renewal. Radioactive liquid waste is addressed in Section 2.1.2 of this SEIS. 

Section 2.2.4 gives more information about STP TPDES permit and permitted discharges, 

including a discussion of the NRC staff’s request for information about the STP TPDES permit 

status.

The Emergency Planning and Community Right-to-Know Act (EPCRA) requires applicable 

facilities to supply information about hazardous and toxic chemicals to local emergency planning 

authorities and EPA (42 USC 11001). On October 17, 2008, EPA finalized several changes to 

the Emergency Planning (Section 302), Emergency Release Notification (Section 304), and 

Hazardous Chemical Reporting (Sections 311 and 312) regulations (63 FR 31268). STP is 

subject to Federal EPCRA reporting requirements; thus, STP submits an annual Section 312 

(Tier II) report on hazardous substances to local emergency response agencies.

2.1.3.2 Pollution Prevention and Waste Minimization

The EPA encourages the use of environmental management systems (EMSs) for organizations 

to assess and manage the environmental impacts associated with their activities, products, and 

services in an efficient and cost-effective manner. The EPA defines an EMS as “a set of 

processes and practices that enable an organization to reduce its environmental impacts and 

increase its operating efficiency.” EMSs help organizations fully integrate a wide-range of 

environmental initiatives, establish environmental goals, and create a continuous monitoring 

process to help meet those goals. The EPA Office of Solid Waste especially advocates the use 
Affected Environment

2-6 

of EMSs at RCRA-regulated facilities to improve environmental performance, compliance, and 

pollution prevention (EPA 2010a). 

Related to the use of EMSs, STP has waste minimization measures in place currently, as 

verified during the STP site visit conducted by NRC in July 2011. In support of nonradiological 

waste-minimization efforts, EPA’s Office of Prevention and Toxics has established a 

clearinghouse that supplies information about waste management and technical and operational 

approaches to pollution prevention (EPA 2010c). The EPA clearinghouse can be used as a 

source for additional opportunities for waste minimization and pollution prevention at STP, as 

appropriate.

2.1.4 Plant Operation and Maintenance

Maintenance activities conducted at STP include inspection, testing, and surveillance to 

maintain the current licensing basis (CLB) of the facility and to ensure compliance with 

environmental and safety requirements. Various programs and activities currently exist at STP 

to maintain, inspect, test, and monitor the performance of facility equipment. These 

maintenance activities include inspection requirements for reactor vessel materials, boiler and 

pressure vessel inservice inspection and testing, the Maintenance Structures Monitoring 

Program, and maintenance of water chemistry.

Additional programs include those carried out to meet technical specification (TS) surveillance 

requirements, those implemented in response to the NRC generic communications, and various 

periodic maintenance, testing, and inspection procedures. Certain program activities are carried 

out during the operation of the unit, while others are carried out during scheduled refueling 

outages. Nuclear power plants must periodically discontinue the production of electricity for 

refueling, periodic inservice inspection, and scheduled maintenance. STP operates on an 

18-month refueling cycle.

2.1.5 Power Transmission System

Nine 345-kV lines were constructed specifically to connect STP to the regional power grid. 

These lines share transmission line corridors and are owned by four service providers: 

American Electric Power Texas Central Company, CenterPoint Energy, City of Austin, and CPS 

Energy. This section summarizes each line and discusses vegetative maintenance procedures. 

Below, the common name for each line appears first, followed by its Electric Reliability Council 

of Texas (ERCOT) name in parentheses. The discussion of the power transmission system is 

adapted from the ER (STPNOC 2010b), the COL application (STPNOC 2010d), STPNOC’s 

October 2011 response to requests for additional information (STPNOC 2011f), or information 

gathered at NRC’s July 2011 environmental site audit. The transmission line description

discusses the entire length of the transmission lines. However, in its analysis, the NRC staff

only considers the portion of the transmission lines extending from STP to the first substation1. 

At STP, an onsite switchyard lies east of the ECP and connects lines from the plant into the 

regional power distribution system. Lines beyond this switchyard have been integrated into the 

 

1

 On June 20, 2013, the NRC published a final rule (78 FR 37282) revising its environmental protection regulation, 10 CFR Part 51, 

“Environmental protection regulations for domestic licensing and related regulatory functions.” A revised GEIS (NRC 2013), which 

updates the 1996 GEIS, provides the technical basis for the final rule. The final rule redefines the number and scope of the 

environmental impact issues that must be addressed by the NRC and applicants during license renewal environmental reviews. 

The rule incorporates lessons learned and knowledge gained from license renewal environmental reviews conducted by the NRC 

since 1996. Among other changes, the final rule revises the definition of in-scope transmission lines to be those “transmission lines 

that connect the nuclear power plant to the substation where electricity is fed into the regional power distribution system and 

transmission lines that supply power to the nuclear plant from the grid.” 
Affected Environment

2-7 

regional electric grid and would stay in service regardless of STP license renewal and, thus, 

would not be affected by the proposed action. Additionally, each of these lines is owned and 

operated by one of four service providers (American Electric Power Texas Central Company, 

CenterPoint Energy, City of Austin, or CPS Energy) rather than the applicant, STPNOC; 

therefore, they are outside of NRC’s regulatory purview. The in-scope transmission lines are 

contained within the footprint of the STP site.

2.1.5.1 Transmission Line Descriptions

Velasco Line (DOW 18 and DOW 27). The Velasco Line is a 45-mi (72-km)–long, double-circuit 

line that extends east from the STP site to the Velasco substation in Brazoria County. Its 

corridor is 100 ft (30 m) wide. CenterPoint Energy owns and operates this line.

Blessing Line (Blessing 44). The Blessing line extends west and then north from the STP site 

for 15 mi (24 km) to its termination point at the Blessing substation in Matagorda County. Its 

corridor is 100 ft (30 m) wide. American Electric Power Texas Central Company owns and 

operates this line.

Hillje Line (Hillje 64). The Hillje line extends 20 mi (32 km) northwest from the STP site to the 

Hillje substation in Wharton County. Its corridor is 400 ft (120 m) wide and is shared with the 

remaining lines discussed in this section. For simplification, this corridor will be referred to as 

the Hillje corridor in this section. CenterPoint Energy owns and operates the Hillje Line.

Hillje W.A. Parrish Loop (WAP 39). The Hillje W.A. Parrish Loop is one of two 20-mi (32-km) 

connector lines that join the STP site to a pre-existing (and out of scope) transmission line, the 

W.A. Parrish-to-Lon Hill Line. The Hillje W.A. Parrish Loop travels along the Hillje corridor. 

CenterPoint Energy owns and operates this line.

Hillje Lon Hill Loop (White Point 39). The Hillje Lon Hill Loop is the second of two 20-mi (32-km) 

connector lines that join the STP site to a pre-existing (and out of scope) transmission line, the 

W.A. Parrish-to-Lon Hill Line. The line travels along the Hillje corridor, and CenterPoint Energy 

owns and operates this line.

Holman Line (Hillje 44). The Holman Line travels through the Hillje corridor and then extends 

northwest for an additional 75 mi (121 km) to the Holman substation in Fayette County. The 

total length of the line is 95 mi (153 km). Beyond the Hillje corridor, the corridor is 100 ft (30 m)

wide. CenterPoint Energy owns and operates the portion of the line within the Hillje corridor, 

and the City of Austin owns and operates the remaining length of the line.

Skyline Line (Elm Creek 27). The Skyline Line travels through the Hillje corridor, extends west 

an additional 119 mi (192 km) to the Elm Creek substation in Guadalupe County, and then 

extends an additional 29 mi (47 km) to the Skyline substation in Bexar County. The total length 

of the line is 168 mi (271 km). Beyond the Hillje corridor, this line’s corridor is 100 ft (30 m)

wide. CPS Energy owns and operates the full length of this line.

Hill Country Line (Elm Creek 18). The Hill Country line follows the same corridor path as the 

Skyline Line. However, the Hill County line extends an additional 12 mi (19 km) from the 

Skyline substation (where the Skyline Line terminates) to the Hill Country Substation in Bexar 

County. The total length of this line is 180 mi (290 km). 

White Point Loop (White Point 39). The White Point Loop is a connector line that joins the STP 

site to the Lon Hill Line. This line is 10 mi (16 km) long and travels along a 100-ft (30-m) wide 

corridor. American Electric Power Texas Central Company owns and operates this line.
Affected Environment

2-8 

2.1.5.2 Transmission Line Maintenance

American Electric Power Texas Central 

Company, CenterPoint Energy, City of Austin, 

and CPS Energy use an integrated vegetative 

management program that combines manual, 

mechanical, biological, and chemical control 

techniques to maintain proper clearance from 

transmission lines and structures. The degree 

and type of clearance varies by line voltage and 

the type, growth rate, and branching characteristics of trees and vegetation. The transmission 

lines traverse predominantly agricultural land and grasslands. Therefore, maintenance activities 

are minimal. Those areas that are not already cultivated or developed in some other way are 

maintained to promote herbaceous vegetation, which includes shrubs, bushes, and other 

low-growing groundcover.

2.1.6 Cooling and Auxiliary Water Systems

STP uses a cooling pond-based heat-dissipation system that withdraws and discharges cooling 

water to the MCR. STPNOC intermittently withdraws and discharges makeup water from the 

lower Colorado River to raise the water level and maintain water quality within the MCR. Unless 

otherwise cited, the NRC staff drew information about STPNOC’s cooling and auxiliary water 

systems from the TPDES Permit (TCEQ 2005) and the applicant’s ER (STPNOC 2010b). 

Circulating Water System. Water is intermittently drawn from the lower Colorado River through 

the Reservoir Makeup Pumping Facility (RMPF) to the MCR. The RMPF is located on the west 

bank of the lower Colorado River and consists of four makeup pumps with a total current 

capacity of approximately 269,000 gallons per minute (gpm) (600 cubic feet per second (cfs) or 

17 m3

/s). STPNOC intermittently draws water from the Colorado River to replace water lost in 

the MCR due to evaporation and seepage. This is depending on weather (patterns of rainfall in 

the river basin), water quality conditions in the MCR, Colorado River flows, operational 

considerations, and TPDES restrictions.

The RMPF withdraws water through a 406-ft (124-m) long intake structure located parallel to the 

shoreline. Water flows through a coarse trash rack with 4-in. (10-cm) openings and into 

traveling water screens (STPNOC 2010d). Each traveling screen is 10-ft (3-m) wide and has a 

mesh size of 3/8 in. (9.5 mm) (STPNOC 2010d, 2010e). A handling and bypass system on the 

traveling screens collects fish caught on the screens and returns them via a sluice downstream 

to the river (STPNOC 2010d). Water that passes through the traveling screens goes into a 

siltation basin, across a sharp-crested weir, and into the pumping station. The water is then 

pumped into the northeast corner of the MCR through two buried 108-in. (274-cm) diameter 

pipelines.

The MCR is a 7,000-ac (2,833-ha) engineered impoundment enclosed by a 12.4-mi (20-km) 

embankment that consists of a clay fill and is lined with a “soil-cement” to prevent erosion

(located adjacent to and south of STP, Units 1 and 2; see Figure 2–1). At the maximum normal 

operating pool of 49 ft (15 m) above mean sea level (MSL), the reservoir contains approximately 

202,700 ac-ft (250 million m3

) of water. The normal operating level is 47 ft (14.3 m) above MSL 

due to a procedural limit for a two-unit operation.

Water flows from the MCR to the main condensers as water is suctioned by four circulating 

water pumps located within the cooling water intake structure (CWIS). Water then passes to a 

common distribution header for the condensers for both units. In the condenser, the circulating 

A transmission line right-of-way (ROW) is a strip 

of land used to construct, operate, maintain, and 

repair transmission line facilities. The 

transmission line is usually centered in the ROW. 

The width of a ROW depends on the voltage of 

the line and the height of the structures. ROWs 

must typically be clear of tall-growing trees and 

structures that could interfere with a powerline.
Affected Environment

2-9 

water absorbs waste heat. Heated water is discharged to the MCR through a discharge 

structure. Each unit circulates 906,957 gpm (3,433 cfs or 97.2 m3

/s) for circulating water flow 

(STPNOC 2009a). 

Dikes within the MCR slow the flow of cooling water from the circulating water system discharge 

structure to the CWIS. As the heated water circulates in the MCR, the heat is gradually 

dissipated to the environment through evaporation, conduction, and long-wave radiative cooling.

To maintain water chemistry and quality within the MCR, STPNOC discharges water from the 

MCR to the Colorado River. Discharge from the MCR enters the Colorado River along the west 

bank through a series of seven 36-in. (91-cm) pipes directed downstream at an angle of 

45 degrees from the shore. The discharge structures are 2 mi (3 km) downstream of the RMPF.

The pipes entering the river are spaced 250 ft (76 m) apart. STPNOC’s TPDES permit limits the 

daily discharge to 144 mgd (5.45 million m3

/d) and shall not exceed 12.5 percent of the flow of 

the Colorado River at the discharge point (TCEQ 2005). The TPDES permit also prohibits 

STPNOC from discharging wastewater when the Colorado River adjacent to the plant is less 

than 800 cfs (22.7 m3

/s). The Texas Administrative Code limits the daily average temperature 

to 95 °F (35 °C) and daily maximum temperature to 97 °F (36 °C) (STPNOC 2010b). STPNOC 

has discharged to the Colorado River once during the operation of STP in 1997 as part of a 

system test (STPNOC 2010b). 

Auxiliary Cooling Water and Essential Cooling Water Systems. The MCR supplies the auxiliary 

cooling water system with cooling water for nonsafety-related systems. Water travels from the 

MCR to the auxiliary cooling water system through a separate bay in the MCR intake structure 

and then heated water discharges to the MCR. The design flow rate is 23,600 gpm (52.6 cfs or 

1.5 m3

/s). 

The essential cooling pond (ECP) supplies the essential cooling water system with cooling 

water for safety-related systems. The ECP is approximately 46 ac (19 ha). Three groundwater 

wells are the primary makeup to the ECP. The design flowrate is 19,280 gpm (43 cfs or 

1.2 m3

/s). After going through the essential cooling water system, the water is discharged to the 

ECP, which is the ultimate heat sink. STPNOC discharges water from the ECP to the MCR to 

maintain water chemistry.

2.1.7 Facility Water Use and Quality

STP, Units 1 and 2, use water systems that include the circulating water systems (CWSs), the 

freshwater and service water systems, the potable and sanitary water systems, and the auxiliary 

cooling water and essential cooling water systems (ECWSs) (see Section 2.1.6). STP uses a 

cooling pond to reject waste heat from normal operations to the atmosphere. The 7,000-ac 

(2,830-ha) MCR is located adjacent to and south of STP, Units 1 and 2 (see Figure 2–1). The 

MCR has a spillway near its southeast corner for the discharge of excess water from the MCR 

to the Colorado River during heavy precipitation events. The MCR also has a buried discharge 

pipe that runs for 1.1 mi (1.8 km), adjacent to the spillway discharge channel, which ends at a 

seven-port outfall. This is STPNOC’s combined outfall (001) under STPNOC’s TPDES permit. 

This pipe allows for the discharge of blowdown (i.e., water high in dissolved solids) from the 

MCR to the Colorado River. The MCR spillway is seldom used, and the blowdown pipeline has 

only been used as part of a test in 1997. The MCR has a normal maximum operating level of 

49 ft (15 m) above MSL for a four-unit operation, but it currently operates under a procedural 

limit of 47 ft (14 m) above MSL for a two-unit operation (STPNOC 2010b). 

The RMPF diverts water from the Colorado River to the MCR to replenish water lost due to 

evaporation and seepage. The RMPF is located on the Colorado River to the east of the 
Affected Environment

2-10

operating units and delivers water to the MCR through two buried 108-in. (274-cm) diameter 

makeup water lines. As currently configured (e.g., screens and pumps), the intake structure has 

a pumping capacity of 269,000 gpm (600 cfs or 17 m3

/s). 

In addition to the water supply from the Colorado River, STPNOC maintains five groundwater 

supply wells at STP as the source for the freshwater and service water systems (including the 

demineralizer system), potable and sanitary water systems, the firewater storage tanks, the 

Nuclear Support Center cooling tower, and fire protection for the Nuclear Training Facility. 

Three of the five onsite wells provide water to the service system and the fire water storage 

tanks, and one well each supports the Nuclear Support Center cooling tower and the Nuclear 

Training Facility (STPNOC 2010b). 

The auxiliary cooling water system draws cooling water for nonsafety-related systems from the 

MCR. Heated water from this system returns to the MCR. The design flow rate of this system 

is 23,600 gpm (53 cfs or 1.5 m3

/s). The essential cooling water system (ECWS) draws cooling 

water for safety-related systems from the ECP. Heated water from this system returns to the 

ECP. The design flow rate for this system is 19,280 gpm (43 cfs or 1.2 m3

/s). Makeup to the 

ECP is from one of the three groundwater wells providing service water and fire water storage. 

The ECP also is equipped with the capability to discharge blowdown to the MCR to maintain 

water chemistry (STPNOC 2010b). 

A description of surface water resources at STP and vicinity is provided in Section 2.2.4, and a 

description of the groundwater resources is presented in Section 2.2.5. The following sections 

further describe the water use from these resources.
Affected Environment

2-11

Figure 2–1. Surface Water Bodies and Groundwater Wells in 

Vicinity of STP (STPNOC 2011b) 
Affected Environment

2-12

2.1.7.1 Surface Water Use 

Feedwater for the STP, Units 1 and 2, CWS is supplied by the MCR, with makeup water for the 

MCR diverted from the lower Colorado River using the RMPF, as previously described. The 

RMPF was designed to accommodate operations of four units at the STP site. Currently, the 

RMPF has 269,000 gpm (600 cfs or 17 m3

/s) of installed pumping capacity to support the 

operation of Units 1 and 2. The MCR also supplies water to the auxiliary cooling water systems, 

which provide cooling for nonsafety-related systems (STPNOC 2010b). 

Through a Certificate of Adjudication issued by the Texas Water Commission, STPNOC has 

priority water rights through the Lower Colorado River Authority (LCRA) to use 102,000 ac-ft/yr 

(126 million m3/yr) of water from the lower Colorado River. STP can withdraw river water up to 

a maximum rate of 540,000 gpm (1,200 cfs or 34.4 m3/s). However, STPNOC’s diversions are 

limited to 55 percent of the flow of the lower Colorado River that is in excess of a 300-cfs 

(8.5-m3

/s) base flow at the diversion point. This is intended to protect freshwater inflows to 

Matagorda Bay during low flow conditions. The Certificate of Adjudication also provides rights 

for an additional 20,000 ac-ft (24.7 million m3

) of water for operation of STP, Units 1 and 2. 

Should sufficient water not be available from the lower Colorado River to maintain the MCR at 

or above an elevation of 27 ft (8.2 m) above MSL, stored water would be released by the LCRA

from sources (i.e., Highland Lakes) upstream of Bay City Dam (STPNOC 2009b, 2010b). 

To operate STP, Units 1 and 2, STPNOC diverted an average of 37,850 ac-ft (46.7 million m3) 

of water per year from the Colorado River between 2003 and 2010. STPNOC’s diversion during 

this period ranged from zero in 2003, due to low flow restrictions, to 72,464 ac-ft 

(89.4 million m3

) during 2009 (STPNOC 2010b, 2011b). 

2.1.7.2 Groundwater Use

Groundwater is withdrawn at STP via five onsite wells to supply the freshwater and service 

water systems, potable and sanitary water systems, and fire protection storage tanks and to 

provide makeup water for the ECWS (see Section 2.1.7).

The five water-supply wells (see Figure 2–1) were installed during construction of STP, Units 1 

and 2, and all are completed in the Deep Chicot Aquifer, as further described in Section 2.2.5. 

These wells range in depth below ground surface (BGS) from 600 to 700 ft (183 to 213 m) and 

have design capacities between 200 and 500 gpm (760 to 1,890 L/min) (NRC 2011b; 

STPNOC 2010b). STP holds a permit from the Coastal Plains Groundwater Conservation 

District (CPGCD) to withdraw 9,000 ac-ft (11.1 million m3

) of groundwater over an approximately 

3-year permit period (CPGCD 2011). This is a pumping rate of approximately 1,860 gpm

(7,040 L/min) or 3,000 ac-ft/yr (3.7 million m3

/yr). Based on data from 2001 through 2010, 

STPNOC’s total annual groundwater production ranged from 682 to 863 gpm (2,580 to 

3,270 L/min) or 1,100 to 1,392 ac-ft/yr (1.4 to 1.7 million m3

/yr) and averaged 768 gpm

(2,910 L/min) or 1,239 ac-ft/yr (1.5 million m3

/yr) (STPNOC 2010b, 2010d, 2011b). 

2.2 Surrounding Environment

Sections 2.2.1 through 2.2.10 provide general descriptions of the environment near STP as 

background information. They also provide detailed descriptions, where needed, to support the 

analysis of potential environmental impacts of operation during the renewal term, as discussed 

in Sections 3 and 4.
Affected Environment

2-13

2.2.1 Land Use

STP is located in Matagorda County, 8 mi (3.2 km) north-northwest of Matagorda and sits 

between Farm-to-Market Road (FM) 1095 to the west and the Colorado River to the east. The 

STP site is located on approximately 12,220 ac (4,945 ha). The operations area, consisting of 

the reactor buildings, support facilities, and transmission ROWs occupies approximately 65 ac

(26 ha); the ECP, approximately 46 ac (19 ha); and the MCR, an additional 7,000 ac (2,833 ha). 

Another 1,700 ac (688 ha) is natural low land habitat. The rest of the site is mostly undeveloped 

land; a portion of which, east of the MCR, is leased for cattle grazing (STPNOC 2010b). 

Onsite facilities include the two reactor and steam generator containment buildings, various 

buildings auxiliary to the reactors such as warehouses, a chemical storage building, switchyard, 

fuel handling buildings, radioactive waste building, training center, outdoor firing range, 

administrative buildings, and miscellaneous supporting buildings (STPNOC 2010b). 

Nearby communities include Matagorda, approximately 8 mi (13 km) north-northwest; Palacios, 

11 mi (18 km) north-northwest; and Bay City, 13 mi (21 km) southeast. The western bank of the 

Colorado River forms the eastern STP property boundary. A 13-ac (5-ha) park, developed by 

the LCRA and operated by Matagorda County, is located on FM 521 on the west side of the 

Colorado River. The Port of Bay City terminal is located approximately 5 mi (8 km) 

north-northeast of the STP site.

2.2.2 Air Quality and Meteorology

STP is located in Matagorda County, a coastal county located on the Gulf of Mexico in the 

southeastern portion of Texas. There are 10 climatic divisions of Texas, with Matagorda County 

falling into the Gulf Coastal Plain, primarily a combination of prairies and marshes. The climate 

for this region is classified as maritime subtropical, which is marked by relatively short, mild 

winters; long, hot summers; and mild springs and falls. The Azores high-pressure system is the 

source of maritime tropical air masses much of the year. During the winter months, occasional 

cold continental air masses displace the maritime air. The STP site is flat with no topographic 

features that would cause the local climate to deviate significantly from the regional climate. 

While tornadoes and floods are the primary weather hazards in the rest of the State, the Gulf 

Coastal Plain is most vulnerable to hurricanes.

The closest first-order National Weather Service (NWS) station representative of the STP site is 

Victoria, Texas, located about 53 mi (85.3 km) to the west of the site. The NWS station at 

Corpus Christi, Texas, about 100 mi (161.0 km) to the southwest, is also representative of the 

site due to its proximity to the coast. Summer climate extends from May through September, 

with the highest average temperatures occurring during July and August, which are 83.8 °F 

(28.8 °C) and 83.7 °F (28.7 °C), respectively. The winter climate extends from December 

through February, with the coldest weather occurring in January at 55.7 °F (13.2 °C) on 

average. The fall climate occurs in October and November, with average temperatures of 

72.6 °F (22.6 °C) and 64.6 °F (18.1 °C) respectively. The spring climate at STP extends from 

March to April, with average temperatures of 65.4 °F (18.6 °C) and 70.2 °F (21.2 °C), 

respectively. The Gulf of Mexico can modify outbreaks of polar air masses such that 

temperatures below 32 °F (0 °C) may occur, on average, less than four times per year.

2.2.2.1 Air Quality

Matagorda County is within the Metropolitan Houston–Galveston Intrastate Air Quality Control 

Region (AQCR). Other counties in the region include Austin, Brazoria, Chambers, Colorado, 

Fort Bend, Galveston, Harris, Liberty, Montgomery, Walker, Waller, and Wharton Counties

(40 CFR 81.38).
Affected Environment

2-14

The EPA regulates six criteria pollutants under the National Ambient Air Quality Standards 

(NAAQS)—carbon monoxide, lead, nitrogen dioxide, ozone, sulfur dioxide, and particulate 

matter. Matagorda County is designated as unclassified or in attainment for all NAAQS criteria 

pollutants. However, the counties of Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, 

Montgomery, and Waller are classified as “[N]onattainment[/]Severe” (40 CFR 81.344) for the 

8-hour ozone standard. These counties are located northeast or north-northeast of Matagorda 

County, with the closest being Brazoria County, located approximately 21 mi northeast of the 

STP site. All other counties in this AQCR are designated as unclassified or in attainment with 

respect to the NAAQS criteria pollutants.

STP has many stationary emission sources, such as standby emergency diesel generators, an 

auxiliary boiler to furnish steam for start-up when the nuclear steam supply is unavailable, and 

several petroleum fuel storage tanks. STP submits a report of air emissions to TCEQ annually. 

Actual total emissions from all sources at STP from 2004 to 2010 were 62.86 tons per year 

(tpy), 58.15 tpy, 56.24 tpy, 47.07 tpy, 60.68 tpy, 59.97 tpy, and 65.37 tpy, respectively. With the 

exception of volatile organic compounds (VOC), the highest emissions were reported in 2004, 

with 1.11 tpy of particulate matter, 12.41 tpy of carbon monoxide, 46.62 tpy of oxides of 

nitrogen, and 0.78 tons per year of sulfur dioxide. The highest VOC emissions were reported in 

2009 and were 2.07 tpy. There are no plans for refurbishment of structures or components at 

the STP site for license renewal. Therefore, there are no changes to expected air emissions 

associated with license renewal (STPNOC 2010b, 2012a) 

Mandatory Class I Federal Areas, where visibility is an important value, are listed in 

40 CFR Part 81, Subpart D. There are no mandatory Class I Federal areas within 50 mi

(81 km) of the STP site. The closest Class I area to STP is the Big Bend National Park located 

in west Texas, which is over 500 mi (805 km) west of the STP site. Due to the significant 

distance from the site and prevailing wind direction, no adverse impacts on Class I areas are 

anticipated from STP operation. Furthermore, there are no expected additional air emissions 

associated with license renewal (no new emission sources). 

STP has had a Meteorological Monitoring Program on site since July 1973. The initial 

measurements were to provide the onsite meteorological information required for licensing of 

STP, Units 1 and 2. Measurements have continued in support of the existing STP, Units 1 

and 2, operations. The primary meteorological tower is approximately 1.5 mi (2.4 km) to the 

east of STP, Units 1 and 2. Its instruments include wind speed and direction and temperature 

sensors at 10 m (33 ft) and 60 m (197 ft) above ground, dew point temperature at 10 m (33 ft) 

above ground, and precipitation and solar radiation near ground level. A 10 m (33 ft) backup 

meteorological tower is located about 0.4 mi (0.6 km) south of the primary tower. 

Instrumentation on the backup tower consists of wind speed and direction and temperature at 

10 m (33 ft). 

2.2.2.2 Meteorology

Wind at the STP site is consistent with the dominant influence of the Azores high-pressure 

system and the coastal location of the site. Seasonal variation of the prevailing directions 

shows a predominance of southeasterly winds except in January, July, and August, when south 

winds prevail, and November and December, when northerly winds prevail. The coastal 

location of the site leads to typical onshore (southeast) winds during the day and offshore winds 

at night.

Precipitation at the STP site ranges from about 2 in. (5.1 cm) per month in February, peaking to 

about 4 to 5 in. (10.2 to 12.7 cm) per month in May and June and again in September and 

October. Snow occurs during more than 50 percent of the winters, but snowfall is generally 

limited to trace amounts. STP can experience severe weather in the form of thunderstorms, 
Affected Environment

2-15

tornadoes, and tropical storms. Thunderstorms are the most frequent severe weather events. 

They occur on an average of about 55 days per year at the Victoria NWS station and about 

31 days per year at Corpus Christi NWS station. The majority of the thunderstorms occur from 

the months of May through September. It is likely that the frequency of thunderstorms at the 

STP site is closer to that of the Corpus Christi NWS station than the Victoria NWS station due to 

Corpus Christi’s proximity to the coastline. Tropical cyclones, including hurricanes and tropical 

storms, pass near the STP site an average of about once every other year, and an average of 

about two to three hurricanes pass near the site every 10 years. Nine hurricanes have made 

landfall between Corpus Christi and Galveston since 1950, the most recent being hurricanes 

Humberto in 2007 and Ike in 2008. Tornadoes are the least frequent of these extreme weather 

events.

2.2.3 Geologic Environment 

This section describes the current geologic environment of the STP site and vicinity including 

landforms, geology, soils, and seismic setting.

Physiography. STP is located within the Coastal Prairies portion of the Texas Gulf Coastal 

Plains physiographic province. The Coastal Prairies subprovince is a broad band paralleling the 

Texas Gulf coasts (BEG 1996). The topography in the immediate vicinity of the site is 

characterized by a relatively flat coastal plain with elevations generally ranging from 20 to 30 ft

(6 to 9 m) above MSL, with an average elevation of 23 ft (7 m) above MSL across STP 

(NRC 2011b; STPNOC 2009a). 

One unique topographic feature in the region is the presence of “pimple mounds,” which can be 

seen throughout the Texas coastal area. These round or elliptical features are typically about 

2 ft (0.6 m) high and 50 ft (15 m) or less in diameter. They are most frequently associated with 

low-lying, poorly drained areas or bodies of water. These mounds are not restricted to a 

specific soil series or type, but they occur on many different types of soils with various moisture 

contents and have no connection to deeper sediments. Although many theories have been 

proposed for their origin, their structure indicates that they result from normal sedimentary 

deposition in calm water environments (STPNOC 2009a). 

Geology. STP sits on the Beaumont depositional plain, one of several such surfaces trending 

northeast-southwest along the Texas Gulf coasts that formed during the Pleistocene Age 

(i.e., between approximately 12,000 and 2.6 million years ago), due to changes in sea level 

associated with coastal subsidence and inland geologic uplift. This plain reflects the uppermost 

surface of a sequence of Quaternary Age sediments approximately 3,000 ft (910 m) thick that 

were deposited by ancient river systems and in deltas. Test borings indicate such sediments 

are present to a depth of at least 2,619 ft (798 m) beneath the site with ages of no more than 

700,000 years. Nevertheless, there has been little modification of this depositional plain since 

the uppermost Beaumont Formation was deposited approximately 70,000 years ago. Today, 

this plain is crossed by the very shallow but relatively wide (4 mi or 6.6 km) Colorado River 

valley, which the river has meandered back and forth across over time (STPNOC 2009a). 

The uppermost geologic unit across and underlying the STP site is the Beaumont Formation,

which is estimated to extend to a depth of 1,400 ft (430 m). The top 125 ft (38 m) of this unit is 

comprised of silt, sandy silt, and fine- to medium-grained sand, interbedded with clay. Clay 

predominates below 125 ft (38 m). Lenses of moderately dense to very dense reddish-brown to 

gray silty sand are found in the clay layers. Along the eastern boundary of the site, Holocene 

(recent) Age alluvial age sediments, which range up to 50 ft (15 m) thick, overlie the Beaumont 

Formation. In addition, Holocene sand, silt, and clay deposits are found in the Colorado River 

meander belt and floodplain east of the plant site. While finer sediments (silt, clay) were 
Affected Environment

2-16

generally deposited in low areas, sand was deposited as point bars or sheet deposits during 

flood stages (STPNOC 2009a). 

No geologic (tectonic) faults capable of producing earthquakes have been identified in the STP 

region, and no unstable subsurface materials or conditions (e.g., salt domes) have been 

identified at the plant site. The closest tectonic faults are located approximately 85 mi (140 km) 

northwest of the STP site in association with the Ouachita geologic province. Many “growth” 

faults have been mapped at depth in the STP site area and extensively studied through 

geophysical data. Common across the Texas Gulf coasts, these features are thought to arise 

from gravity-related processes associated with the consolidation, slumping, and creeping of 

sediments during and after being deposited. At STP, nearly all of these features are confined to 

strata at depths of at least 5,000 ft (1,520 m) BGS in Oligocene age strata comprised of the 

massive marine shales of the Anahuac Formation. This indicates that the growth faults are at 

least as old as the strata in which they are found (i.e., as old as 26 million years) and further 

indicates that they are depositional and not tectonic in nature (STPNOC 2009a). 

Soils. Soil unit mapping by the National Resources Conservation Service (NRCS) identifies the 

natural soils across the STP main plant complex as Laewest clay, 0 to 1 percent slopes, with 

areas of Dacosta sandy clay loam, 0 to 1 percent slopes, to the east and north of the main plant 

complex. These units are deep (greater than 80 in. (200 cm)), moderately well drained soils, 

which developed from clayed clayey fluviomarine deposits. Both soils are prime farmland where 

otherwise not committed to developed uses (7 CFR 675.5). The soils have some limitations for 

site development due to shrink-swell from high expansive clay content and a slight erosion 

hazard (NRCS 2011).

Overall, the plant area excavation consisted of a large open-cut excavation covering the 

footprint of both units to a depth of approximately 40 ft (12 m) BGS. Excavations for the two 

reactor containment buildings (RCBs) extended deeper to nearly 70 ft (21 ft) BGS. These 

excavations penetrated the shallow aquifer zone (see Section 2.2.5 for details), requiring 

groundwater dewatering during construction. The excavated area was backfilled to the 

foundation elevations and to within 18 in. (46 cm) of surface grade with clean, well-graded, 

medium-to-coarse sand. The total amount of Category I structural backfill used for Units 1 

and 2 was approximately 1.6 million tons (1.45 million MT) (STPNOC 2009a). 

Seismic Setting. The central Texas Gulf coast is a region of very low historical seismicity and 

very low seismic risk (USGS 2011a). No earthquakes have been recorded within a radius of 

62 mi (100 km) of STP. Within a radius of 124 mi (200 km), only seven earthquakes have been 

recorded. The closest event was a magnitude 2.7 event with an epicenter 70 mi (113 km) 

northwest of STP (USGS 2011b).

Site and regional studies across the Gulf coasts have concluded that the geologic strata in 

which the previously described growth faults are known to occur are not capable of storing 

strain energy sufficient to produce earthquakes larger than about magnitude 4.0 or shaking 

greater than Modified Mercalli Intensity (MMI) IV or both. Historically, earthquake activity in the 

region attributed to growth faulting has been of magnitude 1.5 or less (microseismic). Further, 

as reported in the applicant’s updated final safety analysis report (FSAR), no earthquakes are 

known to have occurred or been felt at the STP site. Nevertheless, larger earthquakes have 

occurred along the Gulf coasts. The largest historical earthquake in the Gulf coasts region 

occurred in October 1930 near Donaldsonville, Louisiana, approximately 320 mi (515 km) 

east-northeast of the STP site. Although not recorded on instruments, its epicenter and effects 

were based on historical accounts. It is believed to have occurred in the upper basement rock 

rather than in the overlying strata and produced shaking of MMI of V to VI at its epicenter 

(STPNOC 2009a). USGS information provides an estimated magnitude of 4.2 with a 
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conservative MMI of VI for this event (USGS 2011c). Nevertheless, the 1930 Donaldsonville 

earthquake was used as one of the bases to establish the safe shutdown earthquake (SSE) for 

STP where an earthquake producing shaking of MMI VI at the surface was assumed to occur in 

basement rock directly beneath the site. The maximum vibratory (peak) ground acceleration 

(PGA) associated with an MMI VI earthquake is about 0.07 g (i.e., force of acceleration relative 

to that of Earth’s gravity, “g”). Nonetheless, because 0.07 g is below the minimum PGA value in 

10 CFR Part 100, Appendix A, 0.10 g was adopted for the SSE (STPNOC 2009a). 

For the purposes of comparing the SSE with a more contemporary measure of predicted 

earthquake ground motion for the site, the NRC staff also reviewed current PGA data from the 

U.S. Geological Survey (USGS) National Seismic Hazard Mapping Project. The PGA value 

cited is based on a 2 percent probability of exceedance in 50 years. This corresponds to an 

annual frequency (chance) of occurrence of about 1 in 2,500 or 4x10-4 per year. For STP, the 

calculated PGA is approximately 0.03 g (USGS 2008).

2.2.4 Surface Water Resources

The STP site is situated on the west bank of the lower Colorado River, approximately 13 mi

(21 km) southwest of Bay City, Texas, and 10 mi (16 km) north of Matagorda Bay. The STP site 

is approximately 12,200 ac (4.940 ha) in size, the majority of which is occupied by the 7,000-ac 

(2,830-ha) MCR. This reservoir is formed by approximately 12.4 mi (20 km) of embankment 

consisting of clay fill that is constructed above natural ground elevation. The MCR also has 7 mi

(11 km) of internal baffles (raised berms) to enhance the circulation of cooling water 

(STPNOC 2010b). 

As described in Sections 2.1.6 and 2.1.7, the MCR is part of the closed-loop cooling system for 

the normal operations of STP, Units 1 and 2. The CWSs of STP, Units 1 and 2, discharge 

heated water to the MCR, where rejected heat is dissipated mostly via evaporation. To 

replenish the waters lost to evaporation, the RMPF supplies makeup water from the lower 

Colorado River. The pumps in the RMPF are operated intermittently consistent with Colorado 

River flow conditions, operational considerations, and permit restrictions.

2.2.4.1 Surface Water Hydrology

The Colorado River Basin is approximately 42,318 mi2 (109,600 km2

) in area (NRC 2011b). 

STP is located at lower Colorado River Mile 14.6 upstream from Matagorda Bay. The river is 

tidally influenced in the vicinity of the STP site, and this tidal influence extends as far as 32 mi

(51 km) upstream from Matagorda Bay under conditions of low flow. The extent of tidal 

influence depends on tidal fluxes at the mouth of the river, freshwater inflow down the river, and 

other conditions. In addition, saltwater may move as far as 24 mi (39 km) upstream of 

Matagorda Bay, along the bottom of the Colorado River (STPNOC 2010b). The mean annual 

discharge measured at the USGS gauge near Bay City for water years 1949 through 2010 is 

2,620 cfs or 1.17 million gpm (74.1 m3

/s) (USGS 2011d). August is the low-flow month, and 

June is the high-flow month (NRC 2011b). 

Texas experiences frequent droughts, primarily caused by the formation of a stationary 

high-pressure system called the Bermuda High. Multi-year droughts have occurred in the past 

in the Colorado River Basin; for example, annual discharges during 1951 to 1956, 1962 to 1967, 

1983 to 1986, and 1988 to 1991 ranged from 23 to 48 percent, 21 to 79 percent, 25 to 

72 percent, and 21 to 78 percent of the mean annual discharge, respectively (NRC 2011b). Of 
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the 56 years of data reported by USGS from 1949 to 2010 water years,2 the annual discharge 

was less than the mean annual discharge during 26 years.

In the Colorado River Basin, the LCRA operates six dams that impound six Highland Lakes, 

having a combined water storage capacity of 2.18 million ac-ft (2,690 million m3

). The LCRA is 

one of many river authorities that were created by the State legislature to manage surface water 

resources in river basins within the State. The LCRA operates the Colorado River and Lakes 

Buchanan and Travis as a single system for water supply in the lower Colorado River Basin, 

including for STP (see Section 2.1.7.1). Water from the lakes is released when the flow in the 

river is insufficient to meet downstream water rights(NRC 2011b). 

Other noteworthy surface water features at STP include Little Robbins Slough, an intermittent 

stream, which originates approximately 2 mi (3.2 km) northwest of the STP site; it has a 

drainage area of approximately 4 mi2 (10.4 km2

). During construction for Units 1 and 2, the 

original course of Little Robbins Slough was relocated along the west portion of the MCR 

embankment. Currently, the relocated Little Robbins Slough flows south along the west MCR 

embankment, turns east at the southwest corner of the MCR embankment, and rejoins its 

original course approximately 1 mi (1.6 km) east of the southwest corner of the MCR 

embankment (NRC 2011b) (see Figure 2–1). 

Kelly Lake is a 34-ac (14-ha) natural water body located north of the northeast edge of the MCR 

embankment and is fed by a small catchment area to its north. The ECP, which serves as the 

ultimate heat sink for STP, Units 1 and 2, is located east of the power block and comprises 

another 46 ac (19 ha) of land (NRC 2011b; STPNOC 2010b). 

2.2.4.2 Surface Water Quality and Effluents

In support of maintaining the quality of waters of the State and in establishing designated uses 

of surface waters, TCEQ has designated the segment of the lower Colorado River 

(Segment 1401, Colorado River Tidal), adjacent to STP, for use in primary contact recreation 

and for high aquatic life use, as well as for general and fish consumption uses applicable to all 

surface waters (30 TAC 1-307). The numeric water quality criteria specified for the river 

segment include a minimum 24-hour mean dissolved oxygen at any point of 4.0 mg/L, a pH 

range of 6.5 to 9.0 units, an indicator bacteria count of 35 colonies per 100 milliliters (mL), and a 

maximum temperature of 95 °F (35 °C) (NRC 2011b; TCEQ 2011).

The LCRA has a water quality monitoring station on the lower Colorado River at Selkirk Island, 

located approximately 0.7 mi (1.1 km) downstream from the STPNOC’s RMPF. For the period 

of October 1982 through November 2008, dissolved oxygen levels ranged from 0 to 13.5 mg/L 

with an average of 6.5 mg/L, pH ranged from 6.6 to 9.8 units with an average of 7.9, and water 

temperatures ranged from 43.5 to 92.1 °F (6.4 to 33.4 °C) with an average of 72.5 °F (22.5 °C). 

Between 1994 and 2001, fecal coliform ranged from 0 to 13,000 colonies per 100 mL, with an 

average of 391 colonies per 100 mL (NRC 2011b). 

Texas’ draft 2010 Clean Water Act, Section 303(d), list of impaired waters proposes to continue 

the listing of the tidal lower Colorado River as impaired by bacteria; it was first listed for bacteria 

exceedances in 2006 (based on best available information). The other surface water bodies 

near the STP site—including Little Robbins Slough, West Branch of the Colorado River, and 

Kelly Lake—are not on the Section 303(d) list (NRC 2011b; TCEQ 2011).

 

2 For statistical calculations, the USGS does not use years during which data are incomplete. For calculating the annual statistics for 

Colorado River stream flow at Bay City, the USGS did not use water years 1996 through 2000 and 2009. 
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2-19

Wastewater discharges from STP are governed by a TCEQ-issued TPDES permit. This is the 

Texas equivalent of a National Pollutant Discharge Elimination System permit. STPNOC’s 

current TPDES permit (No. WQ0001908000) was issued by TCEQ with an effective date of 

July 27, 2005; the permit expired on December 1, 2009. However, STPNOC submitted a permit 

renewal application to the State on June 2, 2009, which the TCEQ accepted as administratively 

complete on July 13, 2009. Subsequently, TCEQ issued STPNOC its new TPDES permit on 

April 5, 2012, with the new permit having an expiration date of December 1, 2014

(STPNOC 2011d, 2012c, 2013a; TCEQ 2009). Regarding Water Quality Certification 

requirements under Section 401 of the Clean Water Act, TCEQ issued a waiver to STPNOC 

with respect to renewal of STPNOC’s NRC operating licenses as STP discharges are otherwise 

subject to TPDES permitting requirements (STPNOC 2012b). 

The site’s TPDES permit sets effluent limitations for site discharges to the Colorado River from 

the MCR via outfall 001 including comingled recirculated cooling water, MCR blowdown, 

stormwater, uncontaminated groundwater, and makeup water from Colorado River. This also 

includes limits on several “previously monitored” effluent streams or internal outfalls that 

discharge to the MCR and identified as outfall numbers 101, 201, 401, 501, and 601. 

Additionally, the revised permit covers discharges from other miscellaneous sources such as 

MCR relief well water (outfall numbers 002, 003, 004, 005, and 006) and MCR spillway gate 

leakage that may flow to the Colorado River, to the West Branch of the Colorado River, to Little 

Robbins Slough, and to the East Fork of Little Robbins Slough, as appropriate (STPNOC 2012c; 

TCEQ 2005).

In addition to limitations on specific pollutants and on discharge temperature, the current 

TPDES permit requires that the discharge from outfall 001 not exceed 12.5 percent of the flow 

of the Colorado River at the discharge point and prohibits discharges from outfall 001 when river 

flow adjacent to the plant is less than 800 cfs (23 m3

/s). It also imposes an average daily 

discharge flow limit of 144 million gallons per day (mgd) (585,000 m3

/day) (STPNOC 2012c; 

TCEQ 2005). As noted above (and previously in Section 2.1.7), the MCR is equipped with a 

blowdown discharge pipeline to reduce the level of dissolved solids in the circulating water. 

While this blowdown pipeline has only been used once before, it may be necessary to discharge 

from the MCR via outfall 001 in the future to maintain proper circulating water chemistry 

(STPNOC 2010b). 

The NRC staff’s review of the last 3 years of TPDES discharge monitoring reports submitted by 

STPNOC to the TCEQ revealed no exceedances of TPDES effluent limitations. Further, 

STPNOC has not received any Notices of Violation, nonconformance notifications, or related 

infractions associated with the site’s TDPES permit or related to other water quality matters 

within the past 5 years (STPNOC 2011e). 

2.2.5 Groundwater Resources

2.2.5.1 Site Description and Hydrogeology

Underlying the STP site is a wedge of southeasterly dipping sedimentary deposits. Three 

depositional environments are evident—continental (alluvial plain), transitional (delta, lagoon, 

beach), and marine (continental shelf). As further discussed in Section 2.2.3, oscillations of the 

ancient shoreline and other processes have resulted in overlapping mixtures of sediments. 

Numerous local aquifers exist in the thick sequences of alternating and interfingering beds of 

clay, silt, sand, and gravel, which yield groundwater ranging in quality from fresh to saline

(Ryder 1996; STPNOC 2010d). 

The USGS identified the aquifers underlying the STP site as the Texas coastal lowlands aquifer 

system, and it divides the aquifer system into hydrogeologic units or permeable zones A 
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2-20

through E (Ryder and Ardis 2002). Within the State of Texas, both the Texas Water 

Development Board (TWDB) and the LCRA refer to the aquifer system as both the Gulf Coast 

Aquifer system and the coastal lowlands aquifer system, and they use hydrogeologic unit 

names rather than letters to describe the aquifer system (TWDB 2006, 2007; Young et 

al. 2007). Common hydrogeologic unit names, from shallow to deep, are as follows 

(STPNOC 2010d): 

• Chicot Aquifer, 

• Evangeline Aquifer, 

• Burkeville Confining Unit, 

• Jasper Aquifer, 

• Catahoula Confining Unit, and

• Vicksburg–Jackson Confining Unit.

This SEIS adopts the naming convention used by the State of Texas. The aquifers underlying 

the site are located in the Holocene-aged alluvium and the Pleistocene-aged Beaumont, 

Montgomery, Bentley Formations, and Willis Sands that make up the Chicot Aquifer 

(NRC 2011b). In descending order from the land surface, the aquifers of interest are the Upper 

Shallow Chicot Aquifer, the Lower Shallow Chicot Aquifer, and the Deep Chicot Aquifer. The 

Upper and Lower Shallow Chicot aquifers exhibit semi-confined behavior with some movement 

of groundwater between them. Local to STP, Units 1 and 2, this communication between the 

upper and lower zones is also a result of the excavation of the semi-confining material 

separating the two zones during construction of the units. The top of the Upper Shallow Chicot 

Aquifer is designated at approximately 15 to 30 ft (4.6 to 9.1 m) BGS, and its base is at about 

50 ft (15 m) BGS. The Lower Shallow Chicot Aquifer lies between 50 and 150 ft (15 to 46 m)

BGS (NRC 2011b). The depth to groundwater within this shallow aquifer system lies at 

approximately 15 to 20 ft (4.6 to 6.1 m) BGS (MACTEC 2009). The upper surface of the Deep 

Chicot Aquifer is between 250 and 300 ft (76 to 91 m) BGS. The approximate depth where 

groundwater has a total dissolved solids (TDS) concentration of more than 10,000 mg/L defines 

the base of the Deep Chicot Aquifer. Beneath the STP site, the Chicot Aquifer thickness is 

somewhat greater than 1,000 ft (305 m). The Upper Shallow Chicot Aquifer exhibits a 

somewhat higher potentiometric head than the Lower Shallow Chicot Aquifer, and groundwater 

moves from the Upper into the Lower Shallow Chicot Aquifer through the confining zone that 

separates them. The Deep Chicot Aquifer is separated from the Lower Chicot Aquifer by 100 to 

150 ft (30 to 46 m) of low-conductivity confining zone sediments (NRC 2011b). 

Recharge to the Chicot Aquifers underlying the STP site occurs to the northwest of the site, and 

discharge occurs generally to the east, south, and southeast of the site. The Shallow Chicot 

Aquifer outcrops at the land surface, is recharged a few miles northwest of the STP site in 

Matagorda County, and discharges to the Colorado River alluvium near the site. The Deep 

Chicot Aquifer outcrops and is recharged farther north and northwest in Wharton County. It 

discharges into Matagorda Bay and the Colorado River estuary approximately 5 mi (8 km) 

southeast of the STP site. In the upland areas of the aquifer watersheds, where the aquifer 

sediments are exposed at the land surface, infiltration from irrigation also contributes to 

recharge of both the Shallow and Deep Chicot aquifers. The Colorado River is a gaining stream 

where the Shallow and Deep Chicot aquifers discharge to the river (NRC 2011b). The alluvial 

aquifer adjacent to the river also undergoes bank storage, whereby water is retained in and 

discharged from the permeable alluvium of the river bank, with the rise and fall of the Colorado 

River.
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2-21

Additionally, the MCR, as described in Section 2.1.7, is unlined and acts as a local recharge 

source for the Upper Shallow Chicot Aquifer. A series of 770 relief wells surround the MCR 

embankment and collect and discharge some of the seepage from the MCR and otherwise 

relieve hydrostatic pressure on the outer slope and toe of the embankment. Analyses 

presented in the updated FSAR for STP, Units 1 and 2 (STPNOC 2009a), estimate total 

seepage from the MCR into the Upper Shallow Chicot Aquifer at 3,530 gpm or 5,700 ac-ft/yr 

(7 million m3

/yr)). These analyses also estimate that 68 percent of the seepage (2,390 gpm or 

3,850 ac-ft/yr (4.7 million m3

/yr)) from the MCR would be captured by the relief well system for 

an MCR maximum pool elevation of 49 ft (14.9 m) above MSL. More recent simulations of the 

MCR indicate approximately 50 percent capture (NRC 2011b). 

Groundwater quality and aquifer yields dictate that the Deep Chicot Aquifer is the primary 

source of groundwater in the region. STP wells completed in the Deep Chicot Aquifer and used 

for groundwater production at the site are described in Section 2.1.7.2 (see also Figure 2–1). 

The nearest offsite public water supply wells are located in the communities of Selkirk and 

Exotic Isle, which are located adjacent to the STP site eastern boundary. Wells for these 

communities are approximately 1 mi (1.6 km) from the nearest STP production well, Well 7, and 

3.75 mi (6 km) from STP, Units 1 and 2 (see Figure 2–1). Two non-public water supply wells 

used for livestock watering are located about 1,800 ft (549 m) north of STP Well 5 and 2,230 ft

(680 m) west of STP Well 6. They are completed to depths of 500 and 400 ft (152 and 122 m)

and have screened intervals of 200 to 300 ft (61 to 91 m), respectively, above the screened 

intervals of the STP production wells (STPNOC 2010b). 

Groundwater use from the Gulf Coast Aquifer system increased between 1940 and the 

mid-1980s. One cause was rice irrigation, and Matagorda County was among the counties 

where this occurred. As a result of subsidence issues and substantial increases in pumping lift, 

groundwater use has declined in the region. The TWDB forecasts a decline in groundwater use 

from the Gulf Coast Aquifer through 2030. Matagorda County is projected to see a net 

decrease of 48 percent, with pumping decreasing from 21,528 gpm (81,490 L/min) or 31 mgd in 

1985 to 11,111 gpm (42,060 L/min) or 16 mgd in 2030 (Ryder and Ardis 2002). Decreased 

usage, consistent with this estimate, occurred through the year 2000; however, drought periods 

since then have resulted in an increase in groundwater usage.

Established under Texas State law (Water Code, Title 2, Subtitle E, Chapter 36), the CPGCD, 

which has the same boundaries as Matagorda County, has the authority and responsibility to 

define the modeled available groundwater in the district, to define the amount of groundwater 

being used in the district, and to issue permits based on the available groundwater resource. 

The CPGCD is one of approximately 100 such districts in Texas that were created either by the 

Texas legislature or by TCEQ using a local petition process. Groundwater Conservation 

Districts have the authority to regulate the spacing between water wells, the production of water 

from wells, or both. While the River Authorities, such as the LCRA (see Section 2.2.4.1) act as 

managers and suppliers of surface water, and Groundwater Conservation Districts act as 

managers and permitting authorities for groundwater within their respective areas, water 

planning at the regional level is performed by the designated regions, and the TWDB brings the 

Regional Water Plans together to adopt the State Water Plan. Regional and State-level water 

planning consider demands, supplies, and future development of both surface and groundwater 

resources (NRC 2011b). 

The NRC staff interviewed the manager of the CPGCD in July 2011 and learned that the current 

modeled available groundwater in the district (i.e., Matagorda County) is 46,000 ac-ft 

(57 million m3

) annually or 28,522 gpm (107,970 L/min), and the current usage is 36,000 ac-ft 

(44 million m3

) or 22,322 gpm (84,500 L/min). Annual permitted groundwater withdrawals for 

the period 2008 through 2010 (i.e., permits are issued for a 3-year period) were 51,285 ac-ft/yr 
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2-22

(63.2 million m3

) or 31,800 gpm (120,400 L/min) (NRC 2011b). Groundwater use in the largely 

agricultural region encompassing STP fluctuates with the availability of surface water (e.g., with 

the occurrence of drought). Thus, annual permits that total in excess of the modeled available 

groundwater, an annual average value, is not unexpected. As presented in Section 2.1.7.2, 

annual average groundwater use by STP, Units 1 and 2 (i.e., 768 gpm), represents 

approximately 2.7 percent of the modeled available groundwater quantity in Matagorda County 

and 3.4 percent of current usage.

2.2.5.2 Groundwater Quality 

The Shallow Chicot Aquifer exhibits poor water quality and low productivity, and it is used in the 

vicinity of the STP site primarily for livestock watering. However, occasional domestic use is not 

precluded. Of 12 wells completed in the Shallow Chicot Aquifer within 10 mi (16 km) of the STP 

site, 9 wells have TDS concentrations above the EPA secondary drinking water standard (DWS) 

of 500 mg/L (STPNOC 2010b). 

As noted above, the MCR is unlined and acts as a local recharge source for the Upper Shallow 

Chicot Aquifer. Therefore, locally to the STP site, the MCR also influences the groundwater 

quality of the Upper Shallow Chicot Aquifer. A maximum tritium concentration of 

17,410 picocuries per liter (pCi/L) was reported for MCR waters in 1996 (STPNOC 2010b). 

While 50 to 68 percent of the MCR seepage into the aquifer is estimated to be removed by the 

series of 770 relief wells surrounding the MCR embankment, the remainder of the MCR waters 

seep into the aquifer, migrate downgradient, and discharge to the Colorado River southeast of 

the STP site. Monitoring of relief wells and monitoring wells around the MCR has shown that 

tritium from the MCR arrived at relief wells approximately 2 years after plant startup in 1988. It 

arrived at monitoring wells south of the MCR (wells MW-235 and MW-251) in 1999 and 2000 

and at monitoring wells west of the MCR (wells MW-258 and MW-259) in 2006 

(STPNOC 2007, 2011a). 

Since its first detection, the concentration of tritium in relief wells increased to a peak of 

approximately 7,500 pCi/L in 1999 and now varies between 5,000 and 6,000 pCi/L. Since 2000, 

the concentration of tritium in MW-251, which is located south of the MCR, peaked in 2001 and 

then declined somewhat, and has generally remained close to the concentrations in the relief 

wells since then (i.e., 5,000 to 6,000 pCi/L). However, in mid-2012, a spike to 8,600 pCi/L was 

observed in MW-251 before levels declined again. Since its first detection in 2006, the 

concentration of tritium in monitoring wells west of the MCR (i.e., wells MW-258 and 259) has 

increased, peaked, and remained relatively steady since 2009 at around 2,500 pCi/L, although a 

slight increase in concentration to around 3,000 pCi/L was noted at MW-259 toward the end of 

2012. Monitoring wells to the west of the MCR also include wells slightly beyond the site 

boundary (i.e., MW-270 and MW-271), which were observed by the NRC staff during the site 

audit. Since the end of 2010, decreasing tritium concentration levels have been noted in 

MW-271. This well is located adjacent to the STP site boundary in a county road easement. 

In 2012, this well had the highest tritum concentration observed to date at 920 pCi/L, which is 

still a small fraction of the EPA primary DWS. To date, the most distant location at which tritium 

has been detected in shallow groundwater is at MW-267. This onsite station is a windmillpowered well located just northeast of the MCR adjacent to the heavy haul road. Tritium was 

first detected in 2011 and was detected at a slightly above background concentration of 

280 pCi/L in 2012. (STPNOC 2010a, 2012d, 2013b). In summary, all observed values for 

tritium remain below the EPA primary DWS of 20,000 pCi/L (40 CFR Part 141). 

The 2006 annual environmental operating report (STPNOC 2007) presents information 

generated from sampling 18 groundwater wells outside the STP, Units 1 and 2, protected area 
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and from sampling 16 groundwater wells within the STP, Units 1 and 2, protected area. 

Sampling of wells within the protected area resulted from STPNOC’s participation in the Nuclear 

Energy Institute’s (NEI’s) Groundwater Protection Initiative. During site characterization for 

STPNOC’s application for proposed Units 3 and 4, 28 groundwater observation wells were 

installed in 2006, and an additional 26 observation wells were installed in 2008 

(STPNOC 2010d). Since 2006, additional wells have been installed and added to the 

Environmental Monitoring Program to further characterize plumes within the protected area and 

originating from the MCR. For example, during 2008, three additional wells were installed in the 

protected area, and two additional wells were installed outside the protected area.

In 2006, sampling of wells (i.e., 800-series wells) completed in the Shallow Chicot Aquifer within 

the protected area provided eight positive results for tritium, all below the EPA primary DWS of 

20,000 pCi/L (40 CFR Part 141). Eight wells had no detectable tritium. The results were 

attributed to seepage of MCR water into the Shallow Chicot Aquifer and underground pipe 

failures within the protected area. Two of these wells (807 and 808) located between the Unit 1 

and 2 RCBs showed relatively higher values of tritium at 15,000 pCi/L and 1,250 pCi/L 

(STPNOC 2007, 2011b). Tritium concentrations in the wells 807 and 808 decreased to 678 and 

600 pCi/L, respectively, by 2010. Individual wells exhibiting lower concentrations have shown 

trends upward over individual years and over the period from 2005 through 2012. However, 

well sampling within the protected area through 2012 (STPNOC 2011a, 2011b, 2013b) 

continues to show concentrations well below the EPA DWS for tritium. 

In response to the NEI initiative, STPNOC commissioned a report on the groundwater within the 

protected area (MACTEC 2009). Three sources of tritium in groundwater beneath the protected 

area were identified: (1) seepage from the MCR, (2) leaks from the TDS pipeline, and 

(3) discharge from the turbine steam trap drain or steam condensate lines of each reactor. The 

first potential source is limited in concentration to the tritium levels in the MCR and subsequent 

decay in the groundwater pathway from the reservoir. The second source is described as 

having a maximum tritium concentration of 80,000 pCi/L (MACTEC 2009). The third source is 

described as having a maximum tritium concentration of less than 90,000 pCi/L 

(STPNOC 2011d). Within the protected area, the highest tritium concentration in groundwater 

was approximately 15,000 pCi/L in 2006, as described above, but which have since 

substantially declined. The highest tritium concentration in the tendon galleries that circle the 

RCBs was less than 20,000 pCi/L in 2010 (STPNOC 2011d). The latter measurement may be 

indicative of tritium concentrations in groundwater resulting from discharge from the steam 

condensate lines. In 2012, STPNOC completed actions to redirect condensed steam or liquid 

water from the auxiliary steam system to the MCR. STPNOC has evaluated releases inside the 

protected area and concluded that no release is occurring from an unidentified pathway, and 

there is no impact on drinking water or on public health and safety (STPNOC 2011a, 2013b). 

The monitoring program has observed tritium in the shallow aquifer for several years in wells to 

the south of the MCR. The tritium movement is consistent with simulations conducted during 

licensing of STP, Units 1 and 2, as referenced in NRC 2011b, and shows concentrations below 

the EPA DWS. Through 2012, results from STPNOC’s monitoring program indicate generally 

stable tritium concentrations in groundwater wells surrounding the MCR. Higher levels reported 

in some monitoring periods and at select locations may be indicative of drought conditions and 

lower MCR water levels. From the latest STP groundwater monitoring data, the peak onsite 

groundwater tritium concentration in 2012 was 8,600 pCi/L—well below the EPA DWS of 

20,000 pCi/L (STPNOC 2013b). 

Based on groundwater data from 2006 through 2008 presented in the FSAR for proposed STP, 

Units 3 and 4 (STPNOC 2010c), the piezometer head gradient from the existing STP, Units 1 

and 2, to the site boundary to the east is approximately 3 ft (0.9 m), and the distance is 
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approximately 1 mi (1.6 km) (5,280 ft or 1,609 m). Representative values for saturated 

hydraulic conductivity and effective porosity of the lower shallow aquifer are 72 ft/day (22 m/day) 

and 0.31, respectively. The lower shallow aquifer is the more likely pathway for releases in the 

vicinity of the RCBs to offsite receptors (see Section 2.2.5.1) (NRC 2011b). Using these data, 

the travel time from STP, Units 1 and 2, to the site boundary is approximately 100 years. Such 

a travel time within the shallow aquifer presents adequate time for tritium source concentrations 

to decay (i.e., tritium has a 12.3 year half-life) to levels below the EPA DWS.

2.2.6 Aquatic Resources

2.2.6.1 Colorado River and Matagorda Bay

The Colorado River extends approximately 862 mi (1,387 km) from the high plains to the coastal 

marshes in Matagorda County. It is one of the largest river systems within the State of Texas. 

The drainage area for the lower Colorado River basin includes approximately 22,700 mi2

(58,792 km2

), from Lake O.H. Ivie in Mills County, Texas, to Matagorda Bay (TWDB 2007).

STP is located in the Texas coastal plain physiographic province. The section of the Colorado 

River near STP is a diverse, fluvial system that meanders through the coastal plain providing 

sediments and nutrients to Matagorda Bay (ENSR 2008c). The river in this area is generally 

surrounded by steep banks. Little vegetation can grow on the steep banks, but some 

bottomland forests and wetlands occur on land adjacent to the river (ENSR 2008c). 

The Colorado River is tidally influenced near STP, which means that saltwater from Matagorda 

Bay and the Gulf of Mexico regularly flows upstream and mixes with freshwater from the river. 

During periods of low flow, the salinity can reach as high as 20 parts per thousand (ppt) near 

STP (ENSR 2008c). Flow from the gulf and bay influences the aquatic community near STP by 

transporting organisms and increasing the salinity in the river. The distribution and density of 

aquatic plants and animals living in tidally influenced rivers is often determined by salinity 

concentrations.

Environmental History. Freshwater flow between the Colorado River and Matagorda Bay has 

important ecological implications. Flow from the Colorado River can increase the biological 

productivity within Matagorda Bay by providing freshwater, soil, and debris, which can facilitate 

the growth of marsh habitats. Saltwater flow from the bay to the river can influence the species 

distribution and diversity within the river by transporting organisms up the river and providing 

habitat (e.g., higher salinity) for estuarine and marine organisms.

Various development projects have influenced the flow between the Colorado River and 

Matagorda Bay in the past 100 years. Prior to the 1920s, the Colorado River flowed directly into 

Matagorda Bay. In an attempt to control flooding, the U.S. Army Corps of Engineers (USACE) 

dredged a channel down the middle of Matagorda Bay (Holtcamp 2006). The USACE lined the 

channel with the dredged mud, which divided the bay into an eastern and western portion. As a 

result of the lined channel, the water from the Colorado River then flowed directly into the Gulf 

of Mexico (ENSR 2008c).

Dredging projects in the 1950s and 1990s reestablished flow between the Colorado River and 

Matagorda Bay. In the 1950s, the USACE dredged the Tiger Island Channel through the west 

side of Matagorda Bay, re-establishing flow between the river and the bay. In part because of

ecological importance for freshwater to reach the bay, the USACE conducted a series of 

dredging projects to increase the flow from the river to the bay in the 1990s (Holtcamp 2006). In 

1990, the USACE constructed a deeper river diversion channel northwest of the Tiger Island 

Channel. In 1991, the USACE constructed two dams to divert the river flow, including one 

across the Tiger Island Channel (called the Tiger Island Cut Dam, recently renamed to Parker’s 
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Cut) and a diversion dam across the river channel on Matagorda Peninsula. By July 1992, the 

Colorado River flowed directly into Matagorda Bay, through the Gulf Intracoastal Waterway 

(GIWW) and the newly constructed diversion channel. Wilber and Bass (1998) determined that 

the changes in freshwater inflow to Matagorda Bay over time, and the changes to flow from the 

Gulf of Mexico into the Colorado River, have likely influenced the aquatic communities 

historically in the river and bay.

Common Taxa. The most comprehensive studies of the aquatic community within the lower 

Colorado River near STP are studies conducted as part of the licensing processes for STP, 

Units 1, 2, 3, and 4. Below is a brief summary of the aquatic surveys conducted near STP. 

Although the owner of the STP site has changed over time, the owner is referred to as STPNOC 

for simplicity purposes below.

• 1973 to 1974: STPNOC sampled phytoplankton (microscopic floating 

photosynthetic organisms), zooplankton (small animals that float, drift, or 

weakly swim in the water column, including fish and invertebrate eggs and 

larvae), juvenile and adult macroinvertebrates (invertebrates visible without a 

microscope), and juvenile and adult fish (HPLC 1974). NRC (1975) 

summarized these results in the final environmental statement for the 

construction of STP, Units 1 and 2. 

• 1975 to 1976 and 1983 to 1984: Due to the usually wet conditions during the 

1973 to 1974 surveys, STPNOC conducted additional fish surveys in the 

Colorado River in 1975 to 1976 and 1983 to 1984 (McAden 1984, 1985). 

NRC (1986) summarized these results in the final environmental statement 

for the operation of STP, Units 1 and 2. 

• 2007 to 2008: In support of STPNOC’s application to build and operate STP, 

Units 3 and 4, STPNOC sampled macroinvertebrates and fish within the 

Colorado River near STP (ENSR 2008c; STPNOC 2011d). NRC (2011b) 

summarized these results in its final EIS for the proposed construction and 

operation of STP, Units 3 and 4.

Since the Colorado River diversion project, which increased the flow between the Colorado 

River and Matagorda Bay, species diversity and the number of estuarine-marine species 

increased in the Colorado River near STP (NRC 2011b). Because of this change, the summary 

of aquatic organisms focuses on the most current studies. An analysis of the change in the 

aquatic community since the beginning of STP operations is provided in Section 4.5.2.

Phytoplankton: Phytoplankton are microscopic floating photosynthetic organisms that form the 

basis of the food chain. Phytoplankton play key ecosystem roles in the distribution, transfer, 

and recycling of nutrients and minerals. STPNOC most recently surveyed the phytoplankton 

community in the summer of 1973 in the lower Colorado River and an adjacent stretch of

GIWW. STPNOC collected 524 taxa, representing six major divisions (NRC 1975, 2011b). 

Diatoms and cynobacteria (blue-green algae) dominated the phytoplankton community. 

Diatoms were more numerous at the bottom-water samples, and cyanobacteria and 

dinoflagellates were predominant in the water column.

Zooplankton: Zooplankton are small animals that float, drift, or weakly swim in the water 

column. Zooplankton include, among other forms, fish eggs and larvae with limited swimming 

ability, larvae of benthic invertebrates, medusoid forms of hydrozoans, copepods, shrimp, and 

krill (order Euphausiids).

STPNOC surveyed the lower Colorado River and an adjacent stretch of GIWW in 1973 to 1974 

for macrozooplankton (HPLC 1974). STPNOC collected 319 zooplankton species, which 
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included protozoans (101 species), rotifers (75 species), copepods (31 species), and 

cladocerans (27 species) (NRC 1975). The survey showed that the zooplankton community 

structure changed based on salinity, such that during periods of higher salinity (e.g., low river 

flow and strong incoming tides), species diversity increased at upstream stations.

STPNOC most recently surveyed macrozooplankton in 1975 to 1976 and 1983 to 1984 at five 

stations in the lower Colorado River (Figure 2–2). The abundance and occurrence of 

invertebrate eggs and larvae were greatest downstream (Station 5); these decreased in fresher 

water upstream (NRC 1986). In the 1975 to 1976 samples, both freshwater and 

estuarine-marine decapod larvae dominated the macrozooplankton community from May to 

September, and estuarine-marine decapod larvae dominated the community from October to 

December (NRC 1986). The abundance and diversity of decapod larvae were lowest from 

January through April, when the copepod Acartia tonsa was most prevalent (NRC 1986). In 

1983, the most abundant macrozooplankton were cladocerans, Malacostraca species, and 

copepods (NRC 1986). In 1984, the most abundant macrozooplankton were immature stages 

of the Harris mud crab (Rhithropanopeus harrissi), ghost shrimp (Callianassa spp.), and jellyfish 

(family Cnidaria) (NRC 1986).

STPNOC also collected commercially important species, including early life stages of blue crab 

(Callinectes sapidus), white shrimp (Litopenaeus setiferus), and brown shrimp 

(Farfantepenaeus aztecus, formerly known as Penaeus aztecus). In general, the density of 

these species was greatest in higher salinity water (e.g., in the salt wedge or further 

downstream), and lower densities occurred near the STP site (NRC 1975, 1986).

STPNOC most recently collected ichthyoplankton (fish eggs and larvae) in 1975 to 1976 and 

1983 to 1984 at five stations in the lower Colorado River (Figure 2–2). NRC (1986) reported the 

highest densities of ichthyoplankton from May to October 1975 and March to April 1976. 

Densities of ichthyoplankton was highest in higher salinity waters (NRC 1986). The most 

common species were often estuarine or marine species, such as Gulf menhaden (Brevoortia 

patronus), bay anchovy (Anchoa mitchelli), Atlantic croaker (Micropogonia undulatus), and 

naked goby (Gobiosoma bosc) (NRC 1986). In early May and August, when the salinity 

dropped in the Colorado River, the abundance of ichthyoplankton shifted to freshwater drum 

(Aplodinotus grunniens) and cyprinid species (NRC 1986). At the sampling station next to the 

RMPF, STPNOC collected three species (bay anchovy, darter goby (Ctenogobius boleosoma), 

and naked goby), which were three of the most commonly collected species in the survey along 

the lower Colorado River.

Survey results suggest that the lower Colorado River near STP is an estuarine nursery ground 

for many commercially important species including Gulf menhaden, Atlantic croaker, sand 

seatrout (Cynoscion arenarius), spotted seatrout (C. nebulosus), spot croaker (Leiostomus 

xanthurus, also called spot), sheepshead (Archosargus probatocephalus), pigfish (Orthopristis 

chrysopterus), black drum (Pogonias cromis), red drum (Sciaenops ocellatus), and southern 

flounder (Paralichthys dentatus) (NRC 1986).

Adult and Juvenile Macroinvertebrates: STPNOC sampled adult and juvenile 

macroinvertebrates in 1975 to 1976 at eight sampling stations in the Colorado River 

(Figure 2–2). In 1983 to 1984, STPNOC sampled at Station 2, which is closest to the RMPF

(Figure 2–2). In 2007 to 2008, STPNOC sampled along a 9-mi (14-km) stretch of the lower 

Colorado River extending from the GIWW north to the FM 521 bridge (Figure 2–3 and 

Figure 2–4). Within this portion of the river, STPNOC divided the area into three 3-mi (5-km) 

segments and randomly sampled each segment monthly from June 2007 through May 2008. 

Within each month, STPNOC collected samples during a 2-day period randomly selected each 
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month. STPNOC collected samples if the river flow was 5,000 cfs or less to reduce variability in 

sampling conditions.

Figure 2–2. The STP Site and 1975 to 1976 Aquatic Ecology Sampling Location

(NRC 2011b) 
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Figure 2–3. The STP Site and 2007 to 2008 Aquatic Ecology Sampling 

Locations from Segment C through the Upstream Portion of Segment B 

(NRC 2011b) 
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Figure 2–4. The STP Site and 2007 to 2008 Aquatic Ecology Sampling 

Locations from the Downstream Portion of Segment B through Segment A 

(NRC 2011b) 
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All studies used seines and trawls to sample macroinvertebrates. In 2007 to 2008, STPNOC 

also used gill nets and hoop nets primarily to capture fish (ENSR 2008c). However, STPNOC 

collected a few macroinvertebrates in gill nets and hoop nets; therefore, the methodology and 

results of these sampling programs is presented below. ENSR (2008c) used the four different 

types of gear to capture a variety of taxa in terms of size (or life stage) and habitat location 

(e.g., open water vs. benthic). The information below describes the sampling gear used in the 

2007 to 2008 study within each of the three sampling segments (segments A, B, and C) 

(Figure 2–3 and Figure 2–4): 

• Trawls: STPNOC conducted two tows, each for 10 minutes, with a 6.1-m 

(20-ft) otter trawl fitted with a 3.5-cm (1.4-in.) stretched mesh and doors 

(i.e., otter boards) measuring 46 cm by 91 cm (18 in. by 36 in.) attached to 

each wing of the net. The trawl was designed to capture benthic or demersal 

fishes and macroinvertebrates.

• Gill nets: STPNOC set one gill net perpendicular to the shoreline. It set the 

net within 1 hour of sunset and retrieved it at sunrise the following morning. 

The gill net was 33-m (108-ft) long, 1.2-m (3.9-ft) deep, and consisted of 

10.2-cm (4-in.) stretched monofilament mesh. It was designed to capture 

adult fish using shoreline habitats.

• Hoop nets: STPNOC placed one set of hoop nets within 1 hour of sunset and 

retrieved them at sunrise the following morning. Hoop nets consisted of a 

multi-chambered conical net that was 3.6-m (12-ft) long with one 1-m (3-ft) 

diameter hoop at the beginning, followed by smaller hoops, and covered with 

2.5-cm (1-in.) stretched mesh netting. Each hoop net had wings that were 

7.5-m (25-ft) long by 1.8-m (5.9-ft) deep and comprised of 5-cm (2-in.) 

stretched mesh. Hoop nets were designed to capture sub-adult fish using 

shoreline habitats.

• Seines: STPNOC conducted two seine pulls per month for 15.2 m (50 ft) 

parallel to the shoreline. Seines were comprised of a 19-mm (0.75-in.) mesh 

net that measured 18.3-m (60-ft) long and 1.8-m (6-ft) deep. In the center 

was a 1.8 m (6 ft) by 1.8 m (6 ft) by 1.8 m (6 ft) bag that was covered in 

13-mm (0.5-in.) stretched mesh. Seines were designed to capture 

macroinvertebrates and juvenile and sub-adult fishes using shoreline 

habitats.

The most abundant invertebrate species in the 1975 to 1976 and 1983 to 1984 studies were 

river and white shrimp (McAden et al. 1984, NRC 1986). At Station 1, the most upriver station 

near STP, brown shrimp was the most abundant species in trawl samples, and blue crabs were 

the most abundant species in seine samples (NRC 2011b). At Station 2, which is closest to the 

RMPF, STPNOC collected river shrimp, white shrimp, blue crabs, and crayfish (NRC 1986).

In the 2007 to 2008 study, ENSR (2008c) reported the most common species to be white 

shrimp (30 percent), grass shrimp (Palaemonetes pugio) (29 percent), brown shrimp 

(7 percent), and blue crab (4 percent) (Table 2–1). ENSR (2008c) collected macroinvertebrates 

most often in the river segment with the highest salinity (segment A) and least often in the river 

segment with the lowest salinity (segment C) (Figure 2–3 and Figure 2–4). ENSR (2008c) 

reported the greatest density of macroinvertebrates and fish during the following periods:

• Trawls: October through January, 

• Gill Nets: September through December and March through May, 
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• Hoop Nets: October through February and April through June, and

• Seines: January through April. 

Brown, pink (Farfantepenaeus brasiliensis), and white shrimp are of commercial importance in 

the vicinity of the STP site (TPWD 2002; USACE 2007). STPNOC observed various life stages 

of brown and white shrimp in all three studies (NRC 1986; STPNOC 2008c). STPNOC only 

observed pink shrimp during the 1984 to 1985 studies (NRC 1986).

Table 2–1. Macroinvertebrates Collected in the Colorado River 

by Gear Type, 2007 to 2008

Common Name Scientific Name Seine Gill Net

Hoop 

Net Trawl Total % of Total 

Atlantic brief squid Lolliguncula brevis 1 0 0 30 31 <1

Atlantic seabob Xiphopenaeus kroyeri 0 0 0 127 127 2

Blue crab Callinectes sapidus 190 2 3 77 272 4

Brown shrimp 

Farfantepenaeus 

aztecus 264 0 0 192 456 7 

Grass shrimp Palaemonetes pugio 1,762 0 0 1,762 29

white shrimp Litopenaeus setiferus 584 0 0 2,870 3,454 30

Other 11 0 1 12 24 <1

Total invertebrates 2,812 2 4 3,308 6,126

Source: ENSR 2008c 

Adult and Juvenile Fish: STPNOC sampled adult and juvenile fish in 1975 to 1976 at eight 

sampling stations in the Colorado River (Figure 2–3). In 1983 to 1984, STPNOC sampled at 

Station 2, which is closest to the RMPF (Figure 2–3). In 2007 to 2008, STPNOC sampled along 

a 9-mi (14-km) stretch of the lower Colorado River extending from the GIWW north to the 

FM 521 bridge (Figure 2–3 and Figure 2–4). All studies used seines and trawls to sample fish. 

In 2007 to 2008, STPNOC also used gill nets, hoop nets, and trawls (ENSR 2008c). 

ENSR (2008c) followed the same methodology described above for the macroinvertebrate 

sampling.

The most abundant fish species in the 1974 to 1975 study were Gulf menhaden, bay anchovy,

Atlantic croaker, and striped mullet (Mugil cephalus) (NRC 1986). All of these species, except 

for menhaden, were most abundant at sampling stations furthest down the river (NRC 1986). 

Similarly, STPNOC only collected many of the commercially important estuarine species 

(e.g., red drum and southern flounder) at the most downstream station, Station 5. The density 

of menhaden, on the other hand, was greatest at the most upstream station, Station 1.

In the 2007 to 2008 study, STPNOC (2008c) reported the most common species to be Gulf 

menhaden (35 percent), striped mullet (14 percent), black drum (Pogonia cromis) (12 percent), 

and Atlantic croaker (9 percent) (Table 2–2). All other species comprised 3 percent or less of 

the total fish collected. ENSR (2008c) collected fish most often in the river segments with the 

highest salinity (segments A and B) and least often in the river segment with the lowest salinity 

(segment C) (Figure 2–3 and Figure 2–4). 
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Table 2–2. Fish Collected in the Colorado River by Gear Type, 2007 to 2008

Common Name Scientific Name Seine Gill Net

Hoop 

Net Trawl Total

% of 

Total 

Atlantic croaker Micropogonias undulatus 562 1 0 482 1,045 9

Bay anchovy Anchoa mitchilli 24 0 0 264 288 2

Black drum Pogonias cromis 1 1 1 1,360 1,363 12

Blue catfish Ictalurus furcatus 51 22 3 677 753 6

Channel catfish Ictalurus punctatus 22 0 2 6 30 <1

Gafftopsail catfish Bagre marinus 0 9 0 183 192 2

Gizzard shad Dorosoma cepedianum 8 0 2 52 62 <1

Gulf menhaden Brevoortia patronus 2,960 5 2 1,076 4,043 35

Hardhead catfish Ariopsis felis 0 1 1 252 254 2

Red drum Sciaenops ocellatus 8 8 38 25 79 <1

Sailfin molly Poecilia latipinna 150 0 0 0 150 1

Sand seatrout Cynoscion arenarius 22 5 0 294 321 3

Sharptail goby Oligolepis acutipennis 39 0 0 0 39 <1

Sheepshead Archosargus probatocephalus 14 1 6 48 69 <1

Sheepshead 

minnow Cyprinodon variegatus 79 0 0 7 86 <1

Silver perch Bairdiella chrysoura 0 0 0 350 350 3

Smallmouth 

buffalo Ictiobus bubalus 0 32 5 0 37 <1

Spot croaker Leiostomus xanthurus 88 0 1 156 245 2

Spotted seatrout Cynoscion nebulosus 0 4 0 53 57 <1

Star drum Stellifer lanceolatus 0 0 0 86 86 <1

Striped mullet Mugil cephalus 1,676 0 1 1 1,678 14

White mullet Mugil curema 181 0 0 2 183 2

Other 109 15 33 78 235 2

Total Fish 5,994 104 95 5,452 11,645

Source: ENSR 2008c

Species Richness: In the 2007 to 2008 studies, ENSR (2008c) calculated the species richness, 

or number of fish and macroinvertebrate species collected, within each river segment and for 

each type of sampling gear. ENSR (2008c) reported the highest species richness in the river 

segment with the highest salinity (segment A) for trawl, seine, and gill net samples (Table 2–3). 

The species richness was similar across all three-river segments for hoop net samples 

(Table 2–3). 
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Table 2–3. Species Richness (number of species) in Three River Segments by Gear Type

River Segment

Gear Type A B C

Trawl 37 29 24

Seine 38 35 22

Gill nets 14 12 9

Hoop nets 11 12 12

Source: ENSR 2008c 

STPNOC’s studies in the 1970s and 1980s also found greater species diversity and density 

further downstream in higher salinity waters (NRC 1975, 1986). NRC (1975) attributed the 

lower density and diversity near the STP site to the relatively large and frequent fluctuations in 

salinity. Downstream areas, on the other hand, exhibit relatively stable salinity, which allows for 

the establishment of a variety of estuarine and marine species assemblages.

2.2.6.2 Onsite aquatic features

STP is located approximately 23 ft (7 m) above MSL on a site with relatively flat topography. 

Water covers approximately 58 percent of the 12,220 ac (4,945 ha) STP site (STPNOC 2010b). 

The onsite aquatic features include the MCR, the ECP, several sloughs, drainage areas, 

wetlands, and Kelly Lake.

Construction activities for STP, Units 1 and 2, extensively altered several aquatic features on 

the STP site. For example, during the building of the MCR, STPNOC removed up to 65 percent

of the drainage area for Little Robbins Slough in the southern part of the site (NRC 1975). 

STPNOC also created a new channel for the slough, which is the same as the current 

configuration (NRC 2011b). The reconfiguration of Little Robbins Slough reduced the annual 

freshwater runoff into onsite marshes and marshes south of the STP site. Reduced flow can 

displace freshwater species and reduce the quality of nursery grounds for estuarine-dependent 

organisms (NRC 1975). As a result of seepage flow from the MCR into the slough, NRC (1986) 

estimated the total long-term average annual reduction of freshwater input into the marshes to 

be 6 percent. NRC (1986) concluded that, at this rate, the reduction in flow of freshwater from 

the slough into the marshes, and any subsequent changes in salinity or nutrient input, were not 

expected to alter the structure and function of the upper marsh aquatic community (NRC 1986).

Below is a description of the main aquatic features currently located on the STP site.

Main Cooling Reservoir. The MCR is a 7,000-ac (2,833-ha), man-made impoundment that is 

the normal heat sink for waste heat generated during operations of STP, Units 1 and 2. 

STPNOC maintains the water level and quality (e.g., total dissolved solids) in the MCR by 

pumping water from the Colorado River through the RMPF, as described in Section 2.1.6. A 

variety of aquatic organisms currently inhabit the MCR (ENSR 2008a; STPNOC 2010b). 

Aquatic organisms were likely introduced into the MCR when small life stages (e.g., eggs or 

larvae) or species were entrained during the initial filling and subsequent refilling of the MCR.

ENSR (2008a) collected samples of the aquatic community within the MCR four times a year 

from May 2007 through April 2008. ENSR (2008a) sampled the aquatic community at fixed 

stations within five regions of the MCR. Each region was varying distance from the cooling 

water discharge and CWIS. ENSR (2008a) used four different types of gear to capture a variety 

of taxa in terms of size (or life stage) and habitat location (e.g., open water vs. benthic). 

ENSR (2008a) used the following gear types within each region that was sampled:
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• Trawls: STPNOC conducted five tows, each for 10 minutes, with a 6.1-m 

(20-ft) otter trawl fitted with a 3.5-cm (1.4-in.) stretched mesh and doors 

(i.e., otter boards) measuring 46 cm by 91 cm (18 in. by 36 in.) attached to 

each wing of the net. The trawl was designed to capture benthic or demersal 

fishes and macroinvertebrates.

• Gill nets: STPNOC set three gill nets within 1 hour of sunset and retrieved 

them at sunrise the following morning. Gill nets were 91.4-m (300-ft) long, 

3.0-m (10-ft) deep, and consisted of four separate panels measuring 

approximately 22.9-m (75-ft) in length and comprised of 2.5, 5.1, 7.6, and 

10.2-cm (1, 2, 3, and 4-in.) stretched mesh connected in ascending order. 

The grill nets were designed to capture adult fish using open water surface 

habitats.

• Seines: STPNOC conducted one seine pull per sampling event. Seines 

were comprised of 6.4-mm (0.25-in.) mesh net and measured 30.5-m (100-ft) 

long and 3.0-m (10-ft) deep. Seines were designed to capture small 

macroinvertebrates and fish using shoreline habitats.

• Plankton nets: STPNOC conducted three oblique plankton tows through all 

depths of water per sampling event. It used a low speed Henson plankton 

net with a with a dimension of 30-cm (12-in.) mouth width by 120-cm (47-in.) 

length and covered with mesh size of 0.363 mm (0.014 in.). Plankton nets 

were designed to capture pelagic ichthyoplankton, invertebrate larvae, and 

small invertebrates.

ENSR (2008a) collected 11,605 fish and invertebrates using gill nets, seines, and trawls 

(Table 2–4). ENSR (2008a) identified 25 species of fish and invertebrates. Threadfin shad 

(Dorosoma petenense) was the most commonly collected species, representing 62 percent of 

all fish and invertebrates collected using gill nets, seine pulls, or trawls. Other commonly 

collected species include inland silverside (Menidia beryllina) (18 percent), rough silverside 

(Membras martinica) (12 percent), and blue catfish (Ictalurus furcatus) (3 percent) 

(ENSR 2008a). Blue crab was the most commonly collected invertebrate, and it comprised less 

than 1 percent of the total organisms collected using gill nets, seines, and trawls.

ENSR (2008a) collected a total of 5,362 organisms using plankton nets (Table 2–5). Greater 

than 99 percent of the organisms collected were invertebrates (crustaceans), and less than 

1 percent was ichthoplankton (fish eggs and larvae). The most common species (84 percent of 

all plankton net samples) collected were Harris mud crab larvae (ENSR 2008a). ENSR (2008a) 

collected two fish taxa—clupeid shad (Clupeidae spp.) and gobi (Gobiidae spp.).

The fish and invertebrates collected in the MCR suggest that a robust aquatic community has 

developed in the MCR. This community is more representative of an estuarine river rather than 

a freshwater impoundment, likely because the source of fish and invertebrates is from the 

Colorado River during filling of the MCR.

While a diverse aquatic community exists in the MCR, its organisms no longer contribute to the 

riverine ecosystem because they are separate from the Colorado River. In addition, the 

organisms are not available for harvest, and there is no public access or use of the MCR. The 

USACE has determined that the MCR is not waters of the U.S. (USACE 2009), and TCEQ has 

stated that the MCR is not waters of the State (TCEQ 2007).
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Table 2–4. Fish and Invertebrates Collected in the MCR by Gill Nets, 

Seines, and Trawls, 2007 to 2008.

Common Name Fish Scientific Name Gill Net Seine Trawl Total % of Total

Atlantic croaker Micropogonias undulatus 17 86 103 <1

Black drum Pogonias cromis 26 26 <1

Blue catfish Ictalurus furcatus 308 35 50 393 3

Bluegill Lepomis macrochirus 31 31 <1

Channel catfish Ictalurus punctatus 3 21 6 30 <1

Common carp Cyprinus carpio carpio 97 9 106 <1

Freshwater drum Aplodinotus grunniens 7 3 39 49 <1

Gizzard shad Dorosoma cepedianum 45 28 73 <1

Gulf menhaden Brevoortia patronus 4 1 5 <1

Inland silverside Menidia beryllina 2,068 2,068 18

Ladyfish Elops saurus 36 1 37 <1

Gray (mangrove) 

snapper Lutjanus griseus 2 2 <1

Naked goby Gobiosoma bosc 3 3 <1

Needlefish Strongylura exilis 1 1 <1

Pinfish Lagodon rhomboides 3 1 4 <1

Red drum Sciaenops ocellatus 1 1 <1

Rough silverside Membras martinica 1,362 1,362 12

Sheepshead minnow Cyprinodon variegatus 4 4 <1

Smallmouth buffalo Ictiobus bubalus 2 2 <1

Spotted gar Lepisosteus oculatus 1 2 3 <1

Striped mullet Mugil cephalus 1 41 42 <1

Threadfin shad Dorosoma petenense 6,463 768 7,231 62

White mullet Mugil curema 7 7 <1

Invertebrates <1

Blue crab Callinectes sapidus 11 2 6 19 <1

Rangia clam Rangia cuneata 3 3 <1

Total 515 10,091 999 11,605

Source: ENSR 2008a
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Table 2–5. Fish and Invertebrates Collected in the MCR by Plankton Tows, 

2007 to 2008

Common Name Fish Taxa Total % of Total

Clupeid shad Clupeidae spp. 15 <1

Gobi Gobiidae spp. 2 <1

Invertebrates 

Water flea Cladocera spp. 8 <1

Amphipods Amphipoda spp. 1 <1

Copepods Copepoda spp. 22 <1

Fish lice Branchiura spp. 1 <1

Decapods Panopeidae spp. 539 10

Harris mud crab Rhithropanopeus harrissi 4,582 85

Decapod zoea Decapoda spp. 153 3

Brachyuran decapod Brachyura spp. 29 1

Mysid shrimp Mysida spp. 2 <1

Bivalvia Bivalvia spp. 3 <1

Unidentified 5 <1

Total 5,362

Source: ENSR 2008a 

Essential Cooling Pond. The ECP is a 46-ac (19-ha) cooling pond and serves as the ultimate 

heat sink for Units 1 and 2. ENSR (2002) conducted a survey of the ECP and identified two fish 

species: sailfin molly (Poecilia latipinna) and sheepshead minnow (Cyprinodon variegates). 

ENSR (2002) captured fewer fish near the discharge structure compared to elsewhere in the 

ECP. ENSR (2007, 2008c) identified sailfin molly and sheepshead minnow in the main 

drainage channel (MDC) and the Colorado River, and ENSR (2008a) identified sheepshead 

minnow in the MCR.

Other Aquatic Features. Other onsite aquatic features include the Little Robbins Slough, 

wetlands, Kelly Lake, and drainage areas.

Little Robbins Slough is a stream that flows across the site, from the northwest corner, along the

western edge of the MCR embankment, and then out the southwest corner. This water flow is

critical to the function and structure of the marshes both on site and south of the site (Mad 

Island Wildlife Management Area (WMA) and Clive Runnells Family Mad Island Marsh 

Preserve). These marshes provide nursery grounds for juvenile fish and shellfish. The water 

from Little Robbins Slough eventual flows into the GIWW.

Kelly Lake is located in the northeast edge of the MCR embankment (STPNOC 2010d). The 

lake covers approximately 34 ac (14 ha) and is primarily fed by drainage areas but may also 

receive groundwater discharge (STPNOC 2010d). The NRC staff is not aware of any aquatic 

ecology surveys of Kelly Lake (NRC 1975, 1986, 2011b; STPNOC 2010b). 
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The STP site also includes numerous drainage areas, many of which are man-made ditches 

(NRC 2011b). NRC (1975, 1986) included a description of the prevalent aquatic communities 

on the STP site in drainage areas. The most common species from these studies include the 

following: grass shrimp (Palaemonetes kadiakensis; also known as Mississippi grass shrimp), 

crayfish (possibly of several genera), blue crab, red shiner (Cyprinella lutrensis), mosquitofish 

(Gambusia affinis), silverband shiner (Notropis shumardi), sailfin molly, green sunfish (Lepomis 

cyanellus), warmouth (L. gulosus), bluegill (L. macrochirus), white crappie (Pomoxis annularis), 

tidewater silverside (Menidia peninsulae), striped mullet, and several species of killifish (Family 

Cyprinodontidae, likely Lucania spp. and Fundulus spp.). NRC (1975, 1986) reported aquatic 

invertebrates, such as the early life stages of midges, beetles, mayflies, biting midges, 

dragonflies, and damselflies. The fish and invertebrates found in drainage areas are common 

species along the Texas coastline, and most are generally tolerant of salinity and water 

temperature fluctuations (Hassan-Williams and Bonner 2009; NRC 1975, 1986, 2011b; 

STPNOC 2010d; Thomas et al. 2007).

More recently, ENSR (2007) conducted a rapid bio-assessment of the MDC. The MDC is a 

150-m (492-ft) unlined channel that runs north of the proposed STP, Units 3 and 4, power block, 

crosses the existing railroad track, and eventually joins the Little Robbins Slough west of the 

MCR (ENSR 2007; NRC 2011b). STPNOC relocated the MDC further north of the proposed 

STP, Units 3 and 4, power block as part of STPNOC’s proposal to build Units 3 and 4 

(STPNOC 2010e). There is no continual flow of water in the MDC. Saturated soils and possible 

groundwater support shallow pooled areas. Water depth increases during rain events, and 

water drains into Little Robbins Slough during high flows (ENSR 2007; NRC 2011b).

ENSR (2007) conducted the survey using seine nets and followed a modified version of EPA’s 

rapid bioassessment protocols (Barbour et al. 1999). ENSR (2007) identified 11 fish taxa, 

2 invertebrate taxa, and 1 turtle. The three most common species were largemouth bass 

(Micropterus salmoides), mosquitofish, and sailfin mollies. Other species included other sunfish 

species (redear sunfish (Lepomis microlophus), pumpkinseed (L. gibbosus), and bluegill), 

killifish (Bayou killifish (undulus pulverous), Gulf killifish (Fundulus grandis), sheepshead 

minnows), gobies (Gobiidae), inland silverside, crayfish (several genera occur in the area, 

e.g., Procambarus spp.), grass shrimp, and red eared slider (Chrysemys scripta). Similar to the 

fish and invertebrates that inhabited drainages areas in 1970s and 1980s, the taxa found in the 

MDC are common species along the Texas coastline, and most are generally tolerant of salinity 

and water temperature fluctuations (Barbour et al. 1999; Ross 2001; STPNOC 2010d). 

2.2.6.3 Transmission Lines

Power generated from STP during the proposed license renewal term would be transmitted 

using existing transmission line corridors. The transmission corridors pass through forested,

agricultural, and grasslands typical of the Texas coastal prairie (STPNOC 2010b). The water 

bodies crossed by the transmission corridors include small rivers, small streams, agricultural 

ponds, drainage areas, and wetlands (NRC 1975). The NRC staff is not aware of any aquatic 

surveys conducted along these corridors. The NRC staff’s review of the terrain along the Hillje 

transmission line during a pre-application site visit for the proposed STP, Units 3 and 4, did not 

indicate any notable aquatic features within that region of the corridor (NRC 2008a). Observed 

water bodies included wetlands and small ponds. Aquatic species in the water bodies along the 

transmission corridors are likely similar to those communities typically found along the coastal 

plain and are likely tolerant to temporary changes in water quality (NRC 2011b; 

STPNOC 2010d). 
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2.2.7 Terrestrial Resources

STP Ecoregion. Beginning in the 1980s, the USGS, EPA, the Commission for Environmental 

Cooperation, and various other Federal agencies and interagency groups have begun 

delineating North American ecoregions to provide a common geographical framework by which 

to assess and manage the environment. Ecoregions are divided into Levels I through IV; Level I 

encompasses large areas of land and is the broadest category, while Level IV is the most 

specific. Ecoregions are delineated by many factors to include location, climate, vegetation, 

hydrology, terrain, wildlife, and land use. The STP site lies within the following Level I through 

IV ecoregions:

• Level I: Great Plains, 

• Level II: Texas–Louisiana Coastal Plains, 

• Level III: Western Gulf Coastal Plain, and

• Level IV: Floodplains and Low Terraces. 

The Great Plains cover the majority of the midwestern states and are broadly characterized by a 

subhumid to semiarid climate, shortgrass and tallgrass prairie, and little topographic relief 

(EOE 2008). Within the Great Plains, the Texas-Louisiana Coastal Plains contain flat coastal 

plains, barrier islands, dunes, beaches, bays estuaries, and tidal marshes (Wiken et al. 2011). 

Historically, tallgrass prairie dominated the region. Within these coastal plains, STP lies within 

the floodplains and low terraces of the Western Gulf Coastal Plain, a 50- to 90-mi (80- to 

140-km) wide strip of flat land adjacent to the Gulf of Mexico (Griffith et al. 2007). The Western 

Gulf Coastal Plain comprises 1,743 ac (705 ha), with an elevation range of 5 to 200 ft (2 to 

60 m) above MSL (Griffith et al. 2007). The terrain is relatively flat, and grasslands dominate 

undeveloped areas. Inland regions contain some forested land and savannah lies inland, but 

the majority of this ecoregion is used as cropland for rice, cotton, and soybeans (Griffith et 

al. 2007). Other natural features include sloughs, natural levees, and alluvial terraces, as well 

as low gradient streams.

Natural habitats include deciduous bottomland forest and swamps. Maintained lands include 

cropland and pastureland. Common bottomland tree species include pecan (Carya illinoensis), 

water oak (Quercus nigra), southern live oak (Q. virginiana), and elm (Ulmus spp.) (Griffith et 

al. 2007). Baldcypress (Taxodium distichum), black hickory (C. texana), post oak (Q. stellata) 

and winged elm (U. alata) also grow in this region but are not as common (Griffith et al. 2007). 

Coastal marshes contain cordgrass (Spartina spp.), saltgrass (Distichlis spicata), needlerush 

(Juncus spp.), and saltmarsh bulrush (Scirpus paludosus) (Wiken et al. 2011). Common wildlife 

species include white-tailed deer (Odocoileus virginianus), ocelots (Leopardus pardalis), 

jaguarondi (Puma yagouaround), coyote (Canis latrans), ringtail cat (Bassariscus astutus), 

armadillo (Asypus novemcinctus), peccary (Pecari tajacu), swamp rabbit (Sylvilagus aquaticus), 

American alligator (Alligator mississippiensis), ferruginous pygmy-owl (Glaucidium brasilianum), 

green jay (Cyanocorax yncas), Altamira oriole (Icterus gularis), Attwater’s prairie-chicken 

(Tympanuchus cupido attwater), whooping cranes (Grus americana), and various species of 

ducks and geese (Wiken et al. 2011).

STP Site. The STP site occupies about 12,220 ac (4,950 ha) immediately west of the Colorado 

River and approximately 10 mi (16 km) from the river’s confluence with Matagorda Bay 

(STPNOC 2010b). Of that 12,220 ac (4,950 ha), the MCR occupies 7,000 ac; the STP 

buildings, warehouses, and infrastructure occupy about 300 ac (120 ha); and the ECP occupies 

46 ac (19 ha). The remaining land is undeveloped and includes bottomland, agricultural and 

pastureland, wetlands, mixed grasslands, and shrub scrub. ENSR conducted an ecological 
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survey of the STP site between 2006 and 2008. The NRC staff derived the majority of the 

information presented in this section from this assessment.

Along the Colorado River, on the eastern boundary of the STP site, lies about 1,176 ac (476 ha)

of bottomland forested habitat that contains a mixture of trees, shrubs, and grasses. Dominant 

tree species include sugarberry (Celtis laevigata), pecan, cottonwood (Populus spp.), water oak, 

southern live oak, American elm (Ulmus americana), willow (Salix spp.), and Chinese tallow 

(Sapium sebifera). Common shrub species include yaupon (Ilex vomitoria), Chinese privet 

(Ligustrum sinense), McCartney rose (Rosa meizeli), and American beautyberry (Callicarpa 

americana). Grassy areas contain woodoats (Chasmanthium latifolium), carpet grass 

(Axonopus affinis), crab grass (Digitaria spp.), broomsedge, and Bermuda grass (Cynodon 

dactylon). Another 53-ac (21-ha) forested area lies on the STP site north of the heavy haul 

road. The dominant species are the same as in the larger bottomland area (ENSR 2008b). 

Within the west and north of the developed portion of the site lies 976 ac (395 ha) of scrub 

shrub. Sea-myrtle (Baccharis halimifolia), goldenrod (Solidago spp.), ragweed (Ambrosia spp.), 

aster (Aster spp.), southern dewberry (Rubus trivialis), peppervine (Ampelopsis arborea), and 

sumpweed (Iva annua) are the most common vegetation (ENSR 2008b). 

About 486 ac (197 ha) of the site is mixed grasslands, some of which STPNOC regularly mows 

or maintains. Common grass species in these areas include angleton bluestem (Dichanthium 

aristatum), King Ranch bluestem (Bothriochloa ischaemum var. songarica), and bristle grass 

(Setaria spp.) (ENSR 2008b). 

Many wetlands exist on the site, some of which the USACE has determined to be jurisdictional 

wetlands. The non-jurisdictional wetlands include Kelly Lake and a 110-ac (45-ha) managed 

wetland along the northern portion of the site.

Kelly Lake is a 34-ac (14-ha) natural water body within the northeast corner of the site along the 

MCR embankment. It is fed by a small catchment area north of the lake. At least two drainages 

flow into the lake, and one drainage flows south along the east site of the MCR embankment 

and exits the lake (NRC 2011b). Cattail (Typha spp.) and arrowhead (Sagittaria spp.) surround 

Kelly Lake (NRC 2011b).

The 110-ac (45-ha) managed wetland is part of the larger Texas Prairie Wetland Project, a 

series of at least 35,000 ac (14,100 ha) of wetlands along the Gulf coasts that have been set 

aside or restored through a partnership with Ducks Unlimited, the Texas Parks and Wildlife 

Department (TPWD), the U.S. Fish and Wildlife Service (FWS), the U.S. Department of 

Agriculture, and private landowners (Ducks Unlimited 2006). This wetland provides forage and 

wintering habitat for waterfowl, wading birds, and shorebirds (STPNOC 2010b). Houston 

Lighting and Power Company (HPLC), on behalf of STP, signed an agreement in October 1996 

with Ducks Unlimited to manage and restore or enhance this portion of the STP property as part 

of the Texas Prairie Wetlands Project (Ducks Unlimited and HPLC 1996). As part of the 

agreement, HPLC committed to developing and managing the 110 ac (45 ha) to provide 

seasonal or semi-permanent wetland habitat for wintering migratory birds and other 

wetland-dependent wildlife (Ducks Unlimited and HPLC 1996). HPLC also built multiple 

impoundments to create foraging habitat (Ducks Unlimited and HPLC 1996).

The jurisdictional wetlands include 29 small wetlands within the northern portion of the site, 

most of which are ditches or depression wetlands (USACE 2009). The largest delineated 

wetland is 3.78 ac (1.53 ha), and 16 of the delineated wetlands are less than 0.5 ac (0.2 ha)

(ENSR 2008b). In total, jurisdictional wetlands cover 17.6 ac (7.1 ha) (USACE 2009). 

Dominant wetland vegetation includes spikerush (Eleocharis spp.), cattail (Typha spp.), water 

hyssop (Bacopa monnieri), knotgrass (Polygonum spp.), bushy bluestem (Andropogon 
Affected Environment

2-40

glomeratus), sea-myrtle, and rattlebox (Crotalaria spp.) (ENSR 2008b). Additionally, the 

USACE has designated 24,639 linear feet (7,510 linear meters) of non-wetland areas as 

jurisdictional waters.

The most common wildlife on the site include white-tailed deer, rabbit (Silvilgus spp.), squirrel 

(Sciurus spp.), and feral hogs (Sus scrofa) (STPNOC 2010b). Cardinals (Cardinalis cardinalis), 

mourning doves (Zenaida macroura), bobwhite quail (Colinus virginianus), red-winged 

blackbirds (Agelaius phoeniceus), grackles (Quiscalus spp.), black vultures (Coragyps atratus), 

and turkey vultures (Cathartes aura) are the most common birds. Wading birds, such as great 

blue heron (Ardea herodias), great egret (Ardea alba), roseate spoonbill (Ajaia ajaja), white ibis 

(Eudocimus albus), and little blue heron (Egretta caerulea), are common near Kelly Lake, the 

MCR, and other water features (STPNOC 2010b). American alligators, discussed in more detail 

in Section 2.2.7, regularly inhabit the site. Other common reptiles include the copperhead 

snake (Agkistrodon contortrix contortrix), cottonmouth snake (A. piscivorus), eastern hog-nosed 

snake (Heterodon platirhinos), eastern racer (Coluber constrictor), corn snake (Elaphe guttata), 

eastern rat snake (E. obsoleta), diamondback watersnake (Nerodia rhombifer rhombifer), 

eastern box turtle (Terrapene carolina), ornate box turtle (T. ornata), snapping turtle (Chelydra 

serpentina), red-eared pond slider (Trachemys scripta elegans), green anole (Anolis 

carolinensis), and five-lined skink (Eumeces fasciatus) (NRC 2011b). 

Each year, Matagorda County hosts a Christmas Bird Count (CBC), a volunteer bird count 

organized by the Audubon Society that runs from December 14 through January 5 of each year. 

The count centers on Mad Island and encompasses about 113,000 ac (45,700 ha) within a 

15-mi (24-km) radius. Because the STP site lies near the southern terminus of the Central 

Flyway, a great diversity of birds inhabit or pass through the site and surrounding region, and 

the region provides important stopover and wintering habitat for migrating birds. During the 

2010 to 2011 bird count, participants recorded 231 different bird species (Audubon 2011). 

Within the past 5 years of bird count data, red-winged blackbirds (Agelaius phoeniceus) and 

brown-headed cowbirds (Molothrus ater) accounted for the overwhelming majority (70 and 

19 percent, respectively) of recorded observations. Figure 2–5 identifies the most commonly 

observed species in the past 5 years of CBCs. The birds in this figure were of the top 10 most 

commonly recorded species for at least 2 years out of the past five CBCs. In addition to the bird 

species in Figure 2–5, six additional species appeared in the top 10 recorded species for only 

one data year. Table 2–6 lists these species and the year and number of each.

Table 2–6. Birds Observed in High Numbers for One Christmas Count Year, 

2007 through 2011

Species

Year Recorded Within Top 

10 Most Common Species

# of Individuals 

Recorded

American white pelican 2009–2010 1,700

blackbird spp. 2010–2011 5,115

lesser scaup 2010–2011 85,438

redhead 2008–2009 15,005

Ross’s goose 2009–2010 2,537

sandhill crane 2008–2009 10,000

Source: Audubon 2011
2-41

Figure 2–5. Most Commonly Recorded CBC Species, 2007 through 2011 (Audubon 201

American

coot

American

greenwinged

teal

American

robin

boattailed

grackle

Brewer's

blackbird

Brownheaded

Cowbird

common

grackle

greattailed

grackle

greater

whitefronted

goose

northern

pintail

redwinged

blackbird

2010-11 3994 3828 0 4340 0 20752 0 0 10419 0 317446 

2009-10 4315 0 0 11328 0 20626 0 0 2796 3965 62183 

2008-09 6400 0 0 23459 0 26100 5000 10700 0 6878 415000 

2007-08 0 10785 6006 0 5881 792077 93127 133443 0 5432 2561465 

2006-07 0 10785 6006 0 5881 792077 93127 133443 0 5432 2561465 

0

80000

60000

40000

20000

140000

120000

100000

Number of Individuals Observed
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In addition to the data available from the CBCs, ENSR conducted a bird survey in 2006 and 

2007 on the STP site as part of the STP, Units 3 and 4, COL application. 

Table 2–7 lists the bird species that ENSR observed on the STP site during this survey and the 

types of habitats or areas of the site in which each was associated.

Table 2–7. Birds Documented on the STP Site, 2007 through 2008

Species Common Name

Habitat Type or Area 

Observed

Trans-Gulf 

Migrant(a)

Agaelaius phoeniceus red-winged blackbird grassland/scrub-shrub

Anhinga anhinga anhinga MCR

Ardea herodias great blue heron wetland/MCR

Bubulcus ibis cattle egret grassland/wetlands

Buteo jamaicensis red-tailed hawk grassland/scrub-shrub

Buteo lineatus red-shouldered grassland/scrub-shrub

Caracara cheriway crested caracara grassland

Cathartes aura turkey vulture grassland/scrubshrub/developed

Charadrius vociferus killdeer grassland/developed

Circus cyaneus northern harrier grassland/scrub-shrub

Colinus virginianus northern bobwhite grassland/scrub-shrub

Coragyps atratus black vulture grassland/scrubshrub/developed

Corvus brachyrhynchos American crow grassland/scrub-shrub

Cyanocitta cristata bluejay scrub-shrub

Dendrocygna bicolor fulvous whistling-duck wetland

Egretta caerulea little blue heron wetlands

Egretta thula snowy egret wetland/MCR

Egretta tricolor tri-colored heron wetland/MCR

Eudocimus albus white ibis grassland/wetlands

Fulica americana American coot wetlands

Gelochelidon nilotica gull-billed tern MCR

Geothlypis trichas common yellowthroat scrub-shrub x

Haliaeetus leucocephalus bald eagle river shoreline

Hirundo rustica barn swallow grassland/developed x

Leucophaeus atricilla laughing gull MCR/developed

Megaceryle alcyon belted kingfisher wetlands x

Mimus polyglottos northern mockingbird MCR/developed
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Species Common Name

Habitat Type or Area 

Observed

Trans-Gulf 

Migrant(a)

Molothrus ater brown-headed cowbird grassland/scrubshrub/developed

Nycticorax nycticorax black-crowned night-heron grassland/scrub-shrub

Pandion haliaetus osprey wetland

Pelecanus erythrorhynchos American white pelican MCR

Pelecanus occidentalis brown pelican MCR

Petrochelidon pyrrhonota cliff swallow MCR x

Platalea ajaja roseate spoonbill MCR

Progne subis purple martin grassland/scrubshrub/developed x 

Quiscalus major boat-tailed grackle grassland/scrubshrub/developed

Sturnella magna eastern meadowlark grassland/scrub-shrub

Turdus migratorius American robin grassland

Tyrannus forficatus scissor-tailed flycatcher grassland/scrub-shrub x

Zenaida macroura mourning dove grassland/developed

(a) Birds that cross the Gulf of Mexico from the Yucatan Peninsula to the Gulf coasts

Source: ENSR 2008b; NRC 2011b

Waterbirds nest on the ends “Y” dike that directs water flow in the MCR. STPNOC first 

observed nesting on the MCR dikes in 1986 (STPNOC 2010d). The dominate nesting species 

include laughing gulls (Leucophaeus atricilla) (53 percent) and gull-billed terns (Gelochelidon 

nilotica) (31 percent), which account for a collective 84 percent of the 1,200 to 1,600 nests per 

year (STPNOC 2010d). Seven additional bird species nest on the dikes with typically fewer 

than 100 nests each (STPNOC 2010d). 

Transmission Line Corridors. The transmission lines traverse mostly agricultural lands, as well 

as forests and grasslands in 12 counties. The habitat is typical of that described previously 

under “STP ecoregion.” The corridors do not cross any designated critical habitat, Federal or 

State parks, wildlife preserves, refuges, or sanctuaries (STPNOC 2010b). 

Parks and Wildlife Preserves. Many parks and wildlife preserves provide valuable terrestrial 

habitat to native migrating birds. Those in the vicinity of STP are discussed briefly below.

The Brazos Bend State Park is a 5,000-ac (2,000-ha) park located about 35 mi (56 km) 

northeast of the STP site. The TPWD established this park in 1976. Natural habitats include 

the Brazos River floodplains, upland coastal prairie, bottomland hardwood forest, seasonal 

freshwater marshes, and oxbow lakes (TPWD 2011a). The park is home to over 300 species of 

birds, 21 species of reptiles and amphibians, 17 species of mammals, 39 species of dragonflies, 

and 500 species of plants (TPWD 2011a). 

The Mad Island Marsh Preserve lies about 4 mi (6 km) southwest of STP. This preserve is 

situated on West Matagorda Bay around Mad Island Lake and encompasses a total of 7,063 ac 

(2,860 ha) (GCBO 2011). The preserve includes coastal prairie, freshwater wetlands, tidal 
Affected Environment

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saltwater wetlands, and shrubland. The Gulf Coast Bird Observatory has recorded over 

300 species of birds within the preserve, including sandhill cranes (Grus canadensis), cinnamon 

teal (Anas cyanoptera), blue-winged teal (A. discors), northern pintail (A. acuta), Canada goose 

(Branta canadensis), and snow goose (Chen caerulescens) (GCBO 2011). Many habitat 

restoration and enhancement projects within this preserve—including prescribed burns, erosion 

control, and rotational cattle grazing in limited areas—continue to enhance the value of the 

habitat.

The TPWD manages the 7,200-ac (2,900-ha) Mad Island Wildlife Management Area, which lies 

about 3 mi (5 km) south of STP (TPWD 2011d). The State of Texas purchased this parcel of 

land to preserve coastal wetland habitat for wintering waterfowl. The management area 

contains brackish marsh and coastal prairies and provides habitat for a wide variety of wildlife

The FWS manages the Big Boggy National Wildlife Refuge, which lies about 10 mi (16 km) 

southwest of STP (FWS 2011c). Figure 2–6 and Figure 2–7 show the STP 50-mi (80-km)

radius map (STPNOC 2010b) and STP 6-mi (10-km) radius map (STPNOC 2010b), 

respectively. The FWS established this 4,526-ac (1,832-ha) refuge in 1983 to protect saltmarsh 

habitat for migratory birds. Within the refuge, Dressing Point Island in East Matagorda Bay is an 

important rookery for brown pelicans, roseate spoonbills, white ibis, snowy egrets, and other 

colonial nesting birds.
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Figure 2–6. STP 50-mi (80-km) Radius Map (STPNOC 2010b)
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Figure 2–7. STP 6-mi (10-km) Radius Map (STPNOC 2010b)
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2.2.8 Protected Species and Habitats

This section discusses species and habitats that are:

• Federally protected under the Endangered Species Act (ESA) of 1973, as 

amended;

• designated as a species of concern under the National Marine Fisheries 

Service (NMFS)’s Species of Concern Program; 

• Federally protected under the Bald and Golden Eagles Protection Act of 

1940, as amended;

• Federally protected under the Migratory Bird Treaty Act of 1918 (MBTA), as 

amended;

• Federally protected under the Magnuson–Stevens Fishery Conservation and 

Management Act (MSA), as amended;

• Federally protected under the Marine Mammal Protection Act (MMPA) of 

1972, as amended; or

• State-protected under Title 5, Wildlife and Plant Conservation, Chapter 68, 

Endangered Species, and Chapter 88, Endangered Plants, of the State of 

Texas’s Statutes.

2.2.8.1 Species and Habitats Protected Under the Endangered Species Act

The FWS and the NMFS jointly administer the ESA of 1973 (16 USC 1531 et seq.). The FWS 

manages the protection of and recovery effort for listed terrestrial and freshwater species, while 

the NMFS manages the protection of and recovery effort for listed marine and anadromous 

species. 

Action Area

The ESA regulations at 50 CFR 402.02 define “action area” to mean all areas to be affected 

directly or indirectly by the Federal action and not merely the immediate area involved in the 

action. The action area helps to frame the ESA effects analysis because species that occur 

within the action area may be affected by the Federal action, while species that do not occur 

within the action area would likely not be affected by the Federal action. NRC considers the 

action area to include the lands and water bodies described below.

STP site. The STP site lies in a rural area of Matagorda County, Texas, approximately 12 mi 

(19 km) south-southwest of the city limits of Bay City, Texas. The STP site encompasses about 

12,220 ac (4,950 ha) immediately west of the Colorado River and approximately 10 mi (16 km) 

north of the river’s confluence with Matagorda Bay. Of that 12,220 ac (4,950 ha), the MCR

occupies 7,000 ac; the STP reactor and facility buildings, warehouses, switchyard, and other 

infrastructure occupy about 300 ac (120 ha); and the ECP occupies 46 ac (19 ha). The 

remaining land is undeveloped and includes bottomland, agricultural and pastureland, wetlands, 

mixed grasslands, and shrub scrub.

The proposed license renewal would include continued operation of the site, including continued 

use of the MCR for plant cooling water; intermittent withdrawals from the Colorado River to 

provide makeup water to the MCR using the existing reservoir makeup pumping facility; and 

discharges from the MCR to the Colorado River via blowdown pipelines as necessary to 

maintain water quality in the MCR in accordance with the TCEQ-issued Texas Pollutant 
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Discharge Elimination System (TPDES) permit. The proposed license renewal would not 

involve any new construction or refurbishment activities.

Transmission line corridors to the first substation and 0.5-mi (0.8-km) buffer on either side of the 

lines. The proposed license renewal would use the existing onsite switchyard and transmission 

facilities and would not require the construction or modification of the existing transmission 

system. The scope of the transmission lines included in the ESA analysis has been modified 

since the NRC’s issuance of the draft SEIS to include only those portions of the transmission 

lines that extend from the plant to the first substation where electricity is fed into the regional 

power distribution system and the portions of the lines that supply power to the nuclear plant 

from the grid.3

At STP, an onsite switchyard lies east of the ECP and connects lines from the plant into the 

regional power distribution system. Lines beyond this switchyard have been integrated into the 

regional electric grid and would stay in service regardless of STP license renewal; thus, they 

would not be affected by the proposed action. Additionally, each of these lines is owned and 

operated by one of four service providers (American Electric Power Texas Central Company, 

CenterPoint Energy, City of Austin, or CPS Energy) rather than the applicant, STPNOC; 

therefore, they are outside of NRC’s regulatory purview. Thus, the in-scope transmission lines, 

as well as the 0.5-mi (0.8-km) buffer, are contained within the footprint of the STP site. 

Section 2.1.5 describes the transmission line system in more detail.

Colorado River in the vicinity of STP and onsite aquatic features. STP withdraws and 

discharges water to the MCR with intermittent makeup water withdrawals and discharges from 

the lower Colorado River to maintain water level and quality within the MCR. Section 2.2.6 

describes the ecology of the Colorado River as well as other onsite aquatic features, including 

Little Robins Slough, wetlands, Kelly Lake, and drainage areas.

Species and Habitats Under NMFS Jurisdiction

Table 2–8 identifies species under the NMFS’s jurisdiction within Matagorda County. The NRC 

created this list based on correspondence with the NMFS (NMFS 2011c); the FWS’s 

Endangered Species Program online database (FWS 2013a); and TPWD’s Rare, Threatened, 

and Endangered Species of Texas online database (TPWD 2013a).

Table 2–8. ESA Species Under NMFS Jurisdiction That Occur in Matagorda County

Species Common Name Federal 

Status(a)

Fish

Pristis pectinata smalltooth sawfish LE

 

3

 On June 20, 2013, the NRC published a final rule (78 FR 37282) revising its environmental protection regulation, 10 CFR Part 51, 

“Environmental protection regulations for domestic licensing and related regulatory functions.” A revised GEIS (NRC 2013), which 

updates the 1996 GEIS, provides the technical basis for the final rule. The final rule redefines the number and scope of the 

environmental impact issues that must be addressed by the NRC and applicants during license renewal environmental reviews. 

The rule incorporates lessons learned and knowledge gained from license renewal environmental reviews conducted by the NRC 

since 1996. Among other changes, the final rule revises the definition of in-scope transmission lines to be those “transmission lines 

that connect the nuclear power plant to the substation where electricity is fed into the regional power distribution system and 

transmission lines that supply power to the nuclear plant from the grid.” 
Affected Environment

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Species Common Name Federal 

Status(a)

Mammals

Trichechus manatus West Indian manatee LE

Reptiles

Caretta caretta loggerhead sea turtle LT

Chelonia mydas green sea turtle LT

Dermochelys coriacea leatherback sea turtle LE

Eretmochelys imbricata hawksbill sea turtle LE

Lepidochelys kempii Kemp’s ridley sea turtle LE

(a) LE=Federally listed as endangered; LT=Federally listed as threatened

Table Sources: FWS 2013a; NMFS 2011c; TPWD 2013a

The majority of the marine species under NMFS’s jurisdiction that are listed in Table 2–8 occur 

in Matagorda Bay. None of these species would occur in the Colorado River due to their habitat 

requirements; therefore, they do not occur in the action area. Additionally, STPNOC (2010b) 

did not report occurrences of any of these species on the STP site. Therefore, these species 

are not discussed in any further detail in this section.

The NRC staff did not identify any candidate or proposed species or proposed or designated 

critical habitat under NMFS’s jurisdiction within the action area.

Species and Habitats Under FWS Jurisdiction

Table 2–8a identifies species under the FWS’s jurisdiction within the action area. The NRC 

created this list based on the FWS’s Endangered Species Program online database 

(FWS 2013a); the FWS Southwest Region Ecological Services Web site (FWS-SWR 2013); 

TPWD’s Rare, Threatened, and Endangered Species of Texas online database (TPWD 2013a); 

and correspondence between NRC and the U.S. Department of Interior (DOI) and FWS 

(DOI 2013; FWS 2011b). 

The species in this table differ from those included in the draft SEIS for several reasons. Some 

species were removed from the list because they only occur in counties no longer considered 

within the action area due to the revised transmission line scope (see the discussion to the 

action area above and Section 2.1.5). The NRC staff added three candidates for Federal listing. 

The smooth pimpleback (Quadrula houstonensis) and Texas fawnsfoot (Truncilla macrodon) 

were added per DOI’s recommendation in its correspondence with NRC (DOI 2013). The 

addition of Sprague’s pipit (Anthus spragueii) was the result of the NRC staff’s independent 

analysis of species that may occur in the action area. The NRC staff added three Federally 

listed species—the eskimo curlew (Numenius borealis), red wolf (Canis rufus), and Louisiana 

black bear (Ursus americanus luteolus). The TPWD (2013a) lists the eskimo curlew and red 

wolf as historically occurring in Matagorda County and the Louisiana black bear as a transient in 

the county.
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Table 2–8a. ESA Species Under FWS Jurisdiction That Occur in Matagorda County

Species Common Name

Federal 

Status(a)

Birds 

Anthus spragueii Sprague’s pipit C

Charadrius melodus piping plover LT

Falco femoralis septentrionalis northern aplomado falcon LE

Grus americana whooping crane LE

Numenius borealis eskimo curlew LE

Mammals

Canis rufus red wolf LE

Leopardus pardalis ocelot LE

Ursus americanus luteolus Louisiana black bear LT

Mollusks

Quadrula houstonensis smooth pimpleback C

Truncilla macrodon Texas fawnsfoot C

Reptiles

Alligator mississipiensis(b) American alligator LT(SA)

(a) C=Candidate for Federal listing; LE=Federally listed as endangered; LT=Federally 

listed as threatened; LT(SA)=Federally listed as threatened due to similarity of 

appearance

(b)The American alligator is designated as threatened due to similarity of appearance 

with the American crocodile (Crocodylus acutus).

Table Sources: DOI 2013; FWS 2011b, 2013; FWS-SWR 2013; TPWD 2013a

Sprague’s Pipit (Anthus spragueii). The FWS added the Sprague’s pipit to the list of candidate 

species for Federal listing in 2009 (74 FR 63337). Candidate species are not formally protected 

under the ESA but may be protected in the future if listed as threatened or endangered. In its 

most recent Candidate Notice of Review (77 FR 69994), the FWS assigned the Sprague’s pipit 

a listing priority number of (LPN) of 8 in a range of 1 to 12 where 1 is the highest listing priority.

The Sprague’s pipit breeds in the northern Great Plains; migrates through the central Great 

Plains in spring and fall; and winters in southern Arizona and New Mexico, Texas, eastern 

Louisiana, and Mexico. The species is most commonly observed in Texas from mid-September 

to early April. Sprague’s pipit is strongly associated with native upland prairie, is sensitive to 

patch size, and tends to avoid edge habitats (TPWD 2013a). Within Texas, the species inhabits 

heavily grazed grasslands and pastures dominated by little bluestem 

(Schizachyrium scoparium) and Andropogon spp. (Jones 2010). Pipits have also been 

observed on turf grass farms, golf courses, heavily grazed Bermuda grass, and burned 

pastureland (Jones 2010). Threats to the Sprague’s pipit within its wintering range include 

over-grazing, habitat fragmentation or degradation, and development or conversion of 

grasslands.
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The FWS Conservation Plan for the species notes that the second highest density of wintering 

Sprague’s pipits in Texas has been observed on grasslands at the Attwater Prairie Chicken 

National Wildlife Refuge in Colorado County and the Mad Island complex in Matagorda County 

(Jones 2010). During the Audubon Society’s annual CBC, an average of 33 individuals each 

year for the past 15 years (1998 through 2012) have been recorded within the Matagorda 

County-Mad Island Marsh (TXMM) unit, which encompasses about 113,000 ac (45,700 ha) 

within a 15-mi (24-km) radius (Audubon 2013). The most individuals were recorded in 2002 

(78 individuals), while the least number of individuals were recorded in 2003 (14 individuals) 

(Table 2–8b). 

As described in Section 2.2.7, the STP site includes about 486 ac (197 ha) of mixed grasslands, 

and a portion of the site east of the MCR is leased for cattle grazing. These areas of the site 

provide suitable habitat for the Sprague’s pipit. Given the available occurrence information 

above and habitat requirements of the species, the Sprague’s pipit likely occurs in the action 

area. 

Piping Plover (Charadrius melodus). The FWS listed the piping plover as threatened in 1985 

(50 FR 50726). The species occurs through much of the northern Great Plains, Great Lakes 

region, Atlantic coast, and Gulf Coast region. A recent study of the taxonomy of the species 

(Miller et al. 2009) confirmed genetic uniqueness of only two subspecies—Atlantic (C.m. 

melodus) and Interior (C.m. circumcinctus). The FWS recognizes three distinct population 

segments in its ESA rulemakings—the Atlantic Coast, the Great Lakes, and the Northern Great 

Plains populations (FWS 2009). The Atlantic Coast population is C.m. melodus, while the Great 

Lakes and Northern Great Plains populations are C.m. circumcinctus.

The Texas Gulf Coast provides wintering habitat for all three distinct population segments 

between September and March. Piping plover wintering grounds usually consist of ocean 

beaches or sand or algal flats in protected bays with high habitat heterogeneity (Haig 1992). At 

Laguna Madre, Texas, Drake et al. (2001) found piping plovers to be most abundant on algal 

flats in fall and spring months and on exposed sand flats in winter months. Relatively little 

information is known about the piping plover’s winter diet, but the species is known to forage for 

various worms, fly larvae, beetles, crustaceans, mollusks, and other invertebrates in areas of 

open, sparsely vegetated ocean beaches, intertidal flats, and tidal pool edges 

(NatureServe 2013a).

Piping plovers inhabit the nearby shoreline of Matagorda Bay and the Gulf of Mexico near the 

STP site and are regularly observed during the CBC within the TXMM unit. Over the past 

15 years, an average of 36 individuals have been observed in the TXMM unit with a high of 

112 individuals in 2008 and a low of 4 individuals in 1998 (Table 2–8b). However, 

STPNOC (2010b) reported that it has not observed the species on the STP site. Though it is 

possible that the piping plover could occur on the STP site due to the site’s proximity to 

Matagorda Bay, the STP site does not provide suitable habitat for the piping plover. As 

described in Section 2.2.7, the STP site includes developed land, bottomland forest, agricultural 

and pastureland, wetlands, mixed grasslands, and shrub scrub. None of these habitats provide 

open, sandy habitats preferred by the piping plover. In Laguna Madre, Texas, Drake et 

al. (2001) observed non-breeding home ranges to be larger in winter than in fall or spring with 

an overall mean of 12.6 km2 (7.8 mi2). For purposes of conservation and management 

planning, piping plovers are believed to move from areas of suitable habitat a mean linear 

distance of 1.9 km (1.2 mi) in fall, 4.2 km (2.6 mi) in winter, and 3.6 km (2.2 mi) in spring 

(Hammerson and Cannings in NatureServe 2013a). Matagorda Bay, which provides the 

nearest suitable habitat, lies 10 mi (16 km) south of the STP site. Thus, piping plovers are 

unlikely to occur as far north as the STP site and, therefore, would not occur in the action area. 

The NRC will not consider this species in any further detail in this SEIS.
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Piping Plover Critical Habitat. STP is in close proximity to four units of designated piping plover 

critical habitat. The closest critical habitat unit is TX 26, Colorado River Diversion Delta, which 

consists of 13 ac (5 ha) that follow the shore of the northeast corner of West Matagorda Bay 

from Culver Cut to Dog Island Reef (66 FR 36038). This unit is about 7 mi (11 km) south of the 

STP site boundary. It includes roosting areas and is infrequently inundated by seasonal winds. 

The other three units are (66 FR 36038):

(a) TX 23, West Matagorda Peninsular Beach—769 ac (311 ha) of Gulf of Mexico 

shoreline from the Matagorda Ship Channel jetties to the old Colorado River channel,

(b) TX 25, West Matagorda Bay and Eastern Peninsula Flats—575 ac (232 ha) following 

the bayside of Matagorda Peninsula from Maverick Slough southwest for 3 mi 

(5 km), and

(c) TX 27, East Matagorda Bay and Matagorda Peninsular Beach West—728 ac 

(295 ha) of Gulf of Mexico shoreline from the mouth of the Colorado River northeast 

along the peninsula for 14 mi (23 km).

Within these units, only the areas that contain “primary constituent elements” (the physical and 

biological landscape features that a species requires to survive and reproduce) are considered 

critical habitat (FWS 2000). Therefore, buildings, marinas, parking lots, and other developed 

areas do not constitute critical habitat. Though these critical habitat units lie near the STP site, 

they do not occur within the action area.

Northern Aplomado Falcon (Falco femoralis septentrionalis). The FWS listed the northern 

aplomado falcon as endangered in 1986 (51 FR 6686). Historically, this species’ breeding 

range encompassed southern Arizona, New Mexico, and Texas as well as parts of Mexico and 

Guatemala; today, the species may be extirpated from Arizona (NatureServe 2013b). Northern 

aplomado falcons nest along the Gulf Coast of Mexico in northern and central Veracruz, 

northern Chiapas, western Campeche, and eastern Tabasco (Matthews and Moseley 1990). 

Within Texas, the species inhabits open country such as savannah and open woodlands as well 

as grassy plains and valleys with scattered mesquite, yucca, and cactus (TPWD 2013a). The 

FWS (2013b) notes that within these habitats, the essential habitat elements are open terrain 

with scattered trees, relatively low ground cover, an abundance of insects and small to mediumsized birds, and a supply of nest sites.

Northern aplomado falcon breeding pairs usually remain together throughout the year. The 

species typically nests in the abandoned nests of other large birds, such as crows, ravens, 

hawks, and kites (Hector 1990). Females typically lay two to three eggs between January to 

June with peak egg laying occurring in April, and both parents incubate eggs. Young hatch in 

roughly 31 to 32 days and can fly at 4 to 5 weeks, though they may remain in nest area for 

several weeks more. The species primarily hunts at night for small birds and insects

(NatureServe 2013b). 

The species has been recorded during the CBC as occurring within the TXMM unit in 7 of the 

past 15 years (1998 through 2012) (Audubon 2013). Two individuals were recorded in 2003 

and 2008, and one individual was recorded in 2000, 2002, 2005, 2007, and 2009 (Table 2–8b). 

No individuals were recorded in the remaining years. This information indicates that the species 

is present, though rare, in Matagorda Bay. 

Within the STP site boundary, the 976 ac (395 ha) of scrub shrub habitat that lies west and 

north of the developed portion of the site could provide suitable habitat for the northern 

aplomado falcon as could the mixed grasslands and leased pastureland on the site. Thus, this 

species could occur within these areas of suitable habitat in the action area.
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Whooping Crane (Grus americana). The FWS listed the whooping crane as endangered in 1967 

under the Endangered Species Preservation Act of 1966, the predecessor regulation to the 

ESA. The species is currently composed of three populations, one of which—the AransasWood Buffalo National Park Population—migrates to coastal marshes in Texas in the winter 

with significant migration stopovers in southern Saskatchewan, Nebraska, Kansas, and 

Oklahoma (NatureServe 2013c). This population winters at the Aransas National Wildlife 

Refuge in Texas, which lies approximately 35 mi (56 km) south of the STP site (NRC 2011b). 

The other two populations are reintroduced populations: a non-migratory population in central 

Florida and a migratory population that migrates between Wisconsin and Florida 

(NatureServe 2013c).

Whooping cranes migrate to the Texas coast between late October and mid-November and 

generally stay through late March to mid-April (FWS 2011b). Migratory and winter habitat 

includes marshes, shallow lakes, lagoons, salt flats, grain and stubble fields, and barrier islands 

with good horizontal visibility, water depth of 30 cm (12 in.) or less, and minimum wetland size 

of 0.04 ha (0.10 ac) for roosting (NatureServe 2013c). Whooping cranes feed on blue crabs 

(Callinectes sapidus), clams, frogs, minnows, rodents, small birds, and berries (TPWD 2013b). 

Although birds move to uplands to forage for food, they return to the salt marshes in the evening 

to roost. Use of uplands or croplands adjacent to the refuge is rare (TPWD 2013b). 

Whooping cranes fly relatively high when migrating (1,000 to 6,000 ft (300 to 1,800 m) in 

altitude) but will fly lower when searching for stopover habitat (FWS 2011b). These birds may 

fly over the STP site as they migrate through the Central Flyway. However, the whooping crane 

has not been observed on the STP site (STPNOC 2010b), and the inland habitat on the site is 

not likely to provide suitable habitat for the species. Additionally, the whooping crane has not 

been recorded in the TXMM unit during the CBC since 1998 (Table 2–8b). Thus, this species is 

unlikely to occur in the action area, and the NRC will not consider the whooping crane in any 

further detail in this SEIS.

Eskimo Curlew (Numenius borealis). The eskimo curlew migrates annually between breeding 

grounds in North America and wintering grounds in South America. During spring migration 

(beginning in late February to March), the species passes through Central America, crosses the 

Gulf of Mexico into Texas and continues northward through the Midwestern U.S. The last 

confirmed observation of an Eskimo curlew took place in Nebraska in 1987 (76 FR 36491). The 

species could travel through the STP site during migration; however, due to the lack of recorded 

sightings in the past 25 years, the species is unlikely to occur in the action area. Additionally, 

though the TPWD (2013a) identifies this species as occurring historically in Matagorda and 

Brazoria Counties, the FWS’s Endangered Species Program online database (FWS 2013a) 

does not include this species in its lists for any of the three counties. Therefore, the NRC will 

not consider this species in any further detail in this SEIS.

Table 2–8b. TXMM CBC Results for Federally Listed Species, 2008–2012

Species Year Individuals 

Recorded(a)

Individuals 

Recorded/Hours 

Effort

northern aplomado falcon 2000 1 0.0033

(Falco femoralis septentrionalis) 2002 1 0.0027

2003 2 0.0062

2005 1 0.0028

2007 1 0.0027
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2-54

Species Year Individuals 

Recorded(a)

Individuals 

Recorded/Hours 

Effort

2008 2 0.0067

2009 1 0.0032

piping plover 1998 4 0.0122

(Charadrius melodus) 1999 9 0.0253

2000 6 0.0195

2001 22 0.073

2002 31 0.0831

2003 20 0.0618

2004 69 0.1816

2005 26 0.0735

2006 33 0.0863

2007 77 0.2059

2008 112 0.3758

2009 33 0.1068

2010 16 0.0424

2011 50 0.1462

2012 27 0.0754

Sprague’s pipit 1998 21 0.064

(Anthus spragueii) 1999 27 0.0758

2000 49 0.1596

2001 25 0.0829

2002 78 0.2091

2003 14 0.0433

2004 20 0.0526

2005 22 0.0622

2006 24 0.0627

2007 36 0.0963

2008 44 0.1477

2009 68 0.2201

2010 18 0.0477

2011 22 0.0643

2012 23 0.0642

whooping crane 1998 2 0.0061

(Grus americana)

eskimo curlew no records

(Numenius borealis)
Affected Environment

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Species Year Individuals 

Recorded(a)

Individuals 

Recorded/Hours 

Effort

(a) Data from the Matagorda County-Mad Island Marsh (TXMM) unit, which is centered at 

(28.6833 N, -95.9833 W) and encompasses a 15-mi (24-km) radius

Table Source: Audubon 2013

Red Wolf (Canis rufus). The red wolf formerly occurred throughout the eastern half of Texas in 

brushy and forested areas, as well as coastal prairies, but has been recognized by FWS as 

being extinct in the wild since 1980 (Parker et al. 1990). The FWS’s Red Wolf Recovery 

Program has since introduced a captive-bred population of wolves on Alligator River National 

Wildlife Refuge in northeastern North Carolina (FWS 2013c). Red wolves now inhabit five North 

Carolina counties but have not been reintroduced into other states. Thus, the red wolf does not 

occur in the action area, and the NRC will not consider this species in any further detail in this 

SEIS. 

Ocelot (Leopardus pardalis). The ocelot inhabits dense, low brush and requires 70 to 90 percent 

canopy cover (FWS 2011b). The species historically occurred throughout southern Texas but is 

now restricted to southern Edwards Plateau and along the Coastal Plain (TPWD 2011e). This 

species is unlikely to occur on the STP site due to habitat requirements. Therefore, the ocelot is 

unlikely to occur within the action area, and the NRC will not consider this species in any further 

detail is this SEIS.

Louisiana Black Bear (Ursus americanus luteolus). The Louisiana black bear may transiently 

occur within bottomland hardwoods and large tracts of inaccessible forested areas within 

Matagorda County. However, the species is unlikely to occur within the action area due to the 

lack of suitable habitat. Additionally, the FWS (2011b) stated that the species does not occur 

within the area under review for the proposed STP license renewal in a June 2011 letter to the 

NRC. Thus, the NRC will not consider this species in any further detail in this SEIS.

Smooth Pimpleback (Quadrula houstonensis). The smooth pimpleback is a candidate species 

for Federal listing; therefore, it is not formally protected under the ESA. The smooth pimpleback 

inhabits small to moderate streams and rivers as well as moderately sized reservoirs with mixed 

mud, sand, and fine gravel substrate and slow to moderate flow rates (TPWD 2013a). The 

species does not tolerate dramatic water level fluctuations, scoured bedrock substrates, or 

shifting sand bottoms. Smooth pimplebacks occur in the Brazos and Colorado River Basins and 

may occur in the lower Trinity River Basin.

Smooth pimplebacks have not been recorded as occurring in the MCR or the Colorado River in 

the vicinity of STP during any of the ecological studies discussed in Section 2.2.5. Additionally, 

because these waters have become more estuarine over time, the salinity levels would likely 

make any waters within the action area unsuitable for this freshwater mussel. Thus, the NRC 

will not consider this species in any further detail in this SEIS.

Texas Fawnsfoot (Truncilla macrodon). The Texas fawnsfoot is a candidate species for Federal

listing; therefore, it is not formally protected under the ESA. This species occurs in the 

Colorado, Trinity, and Brazos River drainages in Central Texas (NatureServe 2013d). Little is 

known about habitat requirements for this species, but NatureServe (2013d) reports that it 

prefers rivers and larger streams with sand, gravel, or sandy-muddy bottoms and moderate 

flows. The species has not been documented in reservoirs, which suggests an intolerance to 

impoundment (NatureServe 2013d).

Texas fawnsfoot mussels have not been recorded as occurring in the MCR or the 

Colorado River in the vicinity of STP during any of the ecological studies discussed in 
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Section 2.2.5. The species would be unlikely to occur in the MCR due to lack of water flow. 

Additionally, because the MCR and Colorado River within the vicinity of STP have become more 

estuarine over time, the salinity levels would likely make any waters within the action area 

unsuitable for this freshwater mussel. Thus, the NRC will not consider this species in any 

further detail in this SEIS.

American Alligator (Alligator mississipiensis). The FWS listed the American alligator in 1967 

under the Endangered Species Preservation Act of 1966, the predecessor regulation to the 

ESA. Following reclassification actions in several states, the FWS declared the species fully 

recovered in 1987 and reclassified it as “threatened due to similarity of appearance” to the 

American crocodile (Crocodylus acutus) throughout the remainder of the species’ range 

(52 FR 21059). American alligators inhabit coastal swamps from North Carolina southward and 

around the Gulf of Mexico as far west as Texas (Audubon 2004). They also occur in coastal 

flatlands as far north as Arkansas (Audubon 2004).

Alligators inhabit the wetlands on the STP site as well as the MDC and MCR (STPNOC 2010b). 

During a 1987 to 1988 ecological study, Baker and Greene (1989) observed small numbers of 

alligators near Kelly Lake, the south drainage canal, Little Robins Slough, and the various dikes 

associated with the MCR. In 2007 through 2008, ENSR (2008b) did not observe any Federally 

listed species during a threatened and endangered species survey. However, ENSR conducted 

this survey during the winter months, during which time alligators are less active and likely seek 

refuge in swamps and wetlands near the STP site that provide more shelter. American 

alligators are known to inhabit the STP site and, thus, occur within the action area.

2.2.8.2 Species Designated as NMFS Species of Concern

The NMFS established a Species of Concern Program and species of concern list in 2004 to 

distinguish between candidate species under the ESA and other species that the NMFS 

identifies as potentially at risk but for which no ESA listing action has been initiated 

(69 FR 19975). The NMFS defines “species of concern” as “those species about which the 

NMFS has some concerns regarding threats to continued existence and population status, but 

for which insufficient information is available to initiate listing actions under the ESA 

(NMFS 2011d).” 

The term “species of concern” does not appear in either the ESA or its implementing 

regulations; therefore, it does not carry any procedural or substantive protections under the 

ESA. Only the NMFS, and not the FWS, maintains a Species of Concern Program and species 

of concern list. Species of concern in the vicinity of STP appear in Table 2–9. 

Table 2–9. NMFS Species of Concern

Species Common Name Area of Concern(a) Habitat

Anthrozoa 

Oculina varicosa ivory tree coral Atlantic Ocean—West 

Indies, Bermuda, North 

Carolina, Florida, Gulf 

of Mexico, Caribbean

inhabit shallow subtidal waters, 

limestone rubble and ledges, and 

soft-bottom sloping habitats from 

2–152 m in depth

Fish

Carcharhinus obscurus dusky shark Atlantic Ocean; Gulf of 

Mexico; Pacific

surf zone to waters 400 m deep; 

not commonly found in estuaries 

due to salinity requirements
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Species Common Name Area of Concern(a) Habitat

Carcharias taurus sand tiger shark Atlantic Ocean; Gulf of 

Mexico

surf zone to depths of 25 m; 

shallow bays; around coral reefs

Epinephelus 

drummondhayi

speckled hind Atlantic Ocean—North 

Carolina to Gulf of 

Mexico

offshore rocky bottoms with 

depths of 25–183 m; most 

common between 60–120 m

Epinephelus nigritus warsaw grouper Atlantic Ocean—Maine 

southward to Gulf of 

Mexico

continental shelf reefs in waters 

76–219 m deep

Fundulus jenkinsi saltmarsh topminnow Atlantic Ocean—TX, 

LA, MS, AL, FL 

small, tidal marshes with salinity 

of 1–4 ppt

(a) Areas of concern are specified by the NMFS species of concern list (NMFS 2011e). 

Sources: 75 FR 25174; Aronson et al. 2008; Musick et al. 2007; NMFS 2011c; NRC 2011b; Pollard and Smith 2005; 

Wai and Huntsman 2006a, 2006b; WEG 2010

Ivory Tree Coral. The ivory tree coral (Oculina varicosa) inhabits marine waters from Cape 

Hatteras, North Carolina, through the Gulf of Mexico and the Caribbean. However, it is only an 

NMFS species of concern along the eastern U.S. coast from North Carolina through Florida. 

Most of the species’ population is concentrated off east-central Florida, where it occurs in its 

deep-water form and creates thicket-type structures. The species may occur in Matagorda Bay 

in its shallow form, in which the coral forms a symbiotic relationship with zooxanthellae. The 

shallow form reproduces in July and August via broadcast spawning. Ivory tree coral 

suspension feeds on planktonic organisms and provides refuge for over 300 species of 

invertebrates. (NMFS 2010d) 

Sand Tiger Shark. The sand tiger shark (Carcharias taurus) is a species of concern in the 

western Atlantic and northern Gulf of Mexico, though the species is globally distributed in all 

warm and temperate seas and oceans except the eastern Pacific. Tiger sharks mature at about 

6 ft (1.9 m) in length and reach up to 10.4 ft (3.18 m) in length. Individuals are generally solitary 

but occur in schools for feeding, courtship, mating, and birthing. Females give birth to one or 

two pups every other year. Sand tiger sharks migrate toward the equator in fall and winter and 

move poleward during the summer. They prey on bony fishes, small sharks, rays, squid, crabs, 

and lobster. (NMFS 2010e) 

Saltmarsh Topminnow. The saltmarsh topminnow (Fundulus jenkinsi) is a species of concern in 

the coastal waters of Texas, Louisiana, Mississippi, Alabama, and Florida. Saltmarsh 

topminnow occur in estuaries, coastal salt marshes, and back water sloughs and tolerate water 

with salinities of 1 to 20 ppt (NMFS 2009). Females grow up to 60 mm (2.4 in.) in length and 

males grow to 50 mm (1.9 in.) (NMFS 2009). The NMFS (2009) reports that no information on 

reproductive behavior or diet is available for this species.

Other Species of Concern. The dusky shark (Carcharhinus obscurus), speckled hind 

(Epinephelus drummondhayi), and warsaw grouper (Epinephelus nigritus) are unlikely to occur 

in Matagorda Bay due to their habitat requirements.

In addition to the species already discussed, the NMFS (2011c) listed the night shark as a 

species of concern occurring in the vicinity of STP. However, the NMFS (2010c) removed the 

night shark from its species of concern list in 2010. It most often occurs in waters 50 to 100 m 

(160 to 330 ft) deep, but it can inhabit waters as deep as 600 m (2,000 ft) (Santana et al. 2006). 

Because of its depth requirements, the night shark is unlikely to occur in Matagorda Bay.
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2.2.8.3 Species Protected Under the Bald and Golden Eagles Protection Act

The Bald and Golden Eagle Protection Act prohibits anyone from taking bald eagles (Haliaeetus 

leucocephalus) or golden eagles (Aquila chrysaetos), including their nests or eggs, without an 

FWS-issued permit. The term “take” in the Act is defined as to “pursue, shoot, shoot at, poison, 

wound, kill, capture, trap, collect, molest, or disturb” (50 CFR 22.3). “Disturb” means to take 

action that causes injury to an eagle; decreases its productivity by interfering with breeding, 

feeding, or sheltering behavior; or results in nest abandonment (50 CFR 22.3).

Bald eagles are present year-round throughout Texas. Breeding populations primarily inhabit 

the eastern half of the State and the coastal counties from Rockport to Houston 

(Campbell 2003). During ecological surveys associated with the COL application for STP, 

Units 3 and 4, ENSR (2007) listed bald eagles as one of the bird species observed on the STP 

site. An active bald eagle nest lies near the site’s eastern boundary in remote woodlands along 

the Colorado River (NRC 2011b). STPNOC (2010c) first observed this nest site in 2004. A 

second bald eagle nest lies within 6 mi of the STP site (NRC 2011b). 

2.2.8.4 Species Protected Under the Migratory Bird Treaty Act

The FWS administers the MBTA, which prohibits anyone from taking native migratory birds or 

their eggs, feathers, or nests. The MBTA definition of a “take” differs from that of the ESA and 

is defined as “to pursue, hunt, shoot, wound, kill, trap, capture, or collect, or any attempt to carry 

out these activities” (50 CFR 10.12). Unlike a take under the ESA, a take under the MBTA does 

not include habitat alteration or destruction. The MBTA protects 1,007 migratory bird species 

(75 FR 9282). Of these 1,007 species, the FWS allows for the legal hunting of 58 species as 

game birds (FWS undated). Within Texas, the TPWD manages migratory bird hunting seasons 

and associated licenses for ducks, geese, coot, rail, gallinules, snipe, woodcock, doves, and 

sandhill cranes. All Federally and State-listed bird species that appear in Table 2−8a and 

Table 2–11 are protected under the MBTA. MBTA-protected-bird species that commonly occur 

near the STP site are discussed in Section 2.2.6. Additionally, all U.S.-native bird species that 

belong to the families, groups, or species listed in 10 CFR 10.13 are protected under the MBTA.

2.2.8.5 Species Protected Under the Marine Mammal Protection Act

The MMPA established a moratorium on the direct or indirect taking of all species of marine 

mammals in the U.S. The MMPA defines a “take” to mean “to hunt, harass, capture, or kill.” 

The NMFS (for whales, dolphins, porpoises, seals, and sea lions) and FWS (for walrus, 

manatees, otters, and polar bears) may issue take permits for takes that are incidental to 

commercial fishing, scientific research, and other nonfishing activities.

Under the MMPA, the NMFS and FWS manage marine mammals by identifying the “optimum 

sustainable population” level for each species. Those species whose populations have fallen 

below the optimum sustainable level are considered “depleted.” Within the Gulf of Mexico, 

29 marine mammals occur (NMFS 2011b; TMMSN 2011). Of these, only the bottlenose dolphin 

(Tursiops truncates) occurs within Matagorda Bay due to the bay’s shallow depth. Bottlenose 

dolphins inhabit pelagic waters along the continental shelf and may migrate into bays, estuaries, 

and river mouths (NMFS 2011a). Those bottlenose dolphins found in Matagorda Bay are part of 

the Northern Gulf of Mexico Bay, Sound, and Estuarine Stock. According to NMFS’s 2010 stock 

assessment (NMFS 2010a), the status of this stock is unknown because the most recent 

population estimates are eight or more years old, but this stock is not considered depleted. The 

NMFS estimates the larger Northern Gulf of Mexico Coastal stock to be 4,191 individuals as of 

2007 (NMFS 2011a). 
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2.2.8.6 Species Protected Under the Magnuson–Stevens Act

The Gulf of Mexico Fishery Management Council (GMFMC) has designated the lower Colorado 

River, the GIWW, and Matagorda Bay as essential fish habitat (EFH) for many species in 

accordance with the MSA. These waters are collectively referred to as part of Ecoregion 5 in 

the GMFMC’s Final EIS for the Generic Essential Fish Habitat Amendment for Gulf of Mexico

fishery management plans (GMFMC 2004).

Table 2–10 lists those species with designated EFH within Ecoregion 5 and specifies which of 

those species’ life stages have the potential to occur in the vicinity of STP based on each 

stage’s life history requirements.

Table 2–10. Ecoregion 5 Species with Designated EFH

Species Common Name

Fishery 

Management Plan

EFH Life Stages 

in Ecoregion 5(a)

Life Stages in the 

Vicinity of STP(b)

Scomberomorus 

cavalla king mackerel coastal migratory 

pelagic all stages juveniles

Scomberomorus 

maculatus Spanish mackerel coastal migratory 

pelagic all stages all stages

Lutjanus griseus mangrove snapper reef fish all stages all stages

Sciaenops ocellatus red drum red drum all stages all stages

Farfantepenaeus 

aztecus brown shrimp shrimp all stages larvae, juveniles

Farfantepenaeus 

duorarum pink shrimp shrimp all stages larvae, juveniles

Litopenaeus setiferus white shrimp shrimp all stages larvae, juveniles

Menippe adina Gulf stone crab stone crab all stages all stages

(a) “All stages” indicates that egg, larvae, juvenile, and adult EFH are present.

(b) The species’ life stages that do not occur in the vicinity of STP were eliminated based on depth or salinity 

requirements or both, which are presented in GMFMC’s Final EIS for the Generic Essential Fish Habitat 

Amendment for Gulf of Mexico fishery management plans (GMFMC 2004). 

A brief discussion of each EFH species appears below. This section summarizes information 

on each species from the GMFMC’s Final EIS for the Generic Essential Fish Habitat 

Amendment for Gulf of Mexico fishery management plans (GMFMC 2004) unless otherwise 

noted.

King and Spanish Mackerel. King mackerel (Scomberomorus cavalla) and Spanish mackerel 

(Scomberomorus maculates) occur in the Gulf of Mexico. Concentrated populations of king 

mackerel occur in the coastal waters of South Florida and Louisiana, and the most concentrated 

population of Spanish mackerel is off the coast of Florida. Adults of both species generally 

inhabit reefs and coastal waters with salinity ranging from 32 to 36 ppt. Spanish mackerel 

prefer waters of up to 75 m (250 ft) and will occasionally inhabit estuaries. King mackerel 

inhabit waters up to 200 m (660 ft), though they most often occupy waters less than 80 m 

(260 ft). Adult king mackerel eat jacks, snappers, grunts, halfbeaks, penaeid shrimp, squid, 

and—less commonly—crustaceans and mollusks. Spanish mackerel eat clupeids, engraulids, 

carangids, and squid. Predators of both species include pelagic sharks, little tunny, and 

dolphin.
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King mackerel spawn over the outer continental shelf from May to October, while Spanish 

mackerel spawn over the inner continental shelf. Both species’ eggs are pelagic and buoyant. 

King mackerel larvae inhabit the middle and outer continental shelf, while Spanish mackerel 

larvae move to the inner continental shelf. Larvae consume smaller larval fish such as 

carangids, clupeids, and engraulids. Young tuna and dolphins prey upon king mackerel larvae. 

Juveniles inhabit both offshore and estuarine waters and eat smaller fish and invertebrates. 

Little tunny, dolphin, and other pelagic fish prey on juveniles.

Mangrove Snapper. Larval, juvenile, and adult mangrove snapper (Lutjanus griseus) primarily 

occupy inshore habitats, such as estuaries and continental shelf waters up to 180 m (590 ft) in 

depth. They inhabit waters about 32 km (20 mi) offshore and inshore waters through freshwater 

creeks and rivers. Mangrove snappers use a wide variety of habitats, including mangrove, 

sandy grassbeds, and coral reefs. Mangrove snapper spawn pelagic eggs off shore near reefs 

from June to August. As larvae grow, they move inshore toward estuarine habitats, especially 

those with dense beds of Halodule and Syringodium sea grasses. As with adults, juveniles 

inhabit marine, estuarine, and riverine habitats. Juveniles and adults are most often found near 

mangroves, where they forage on small fish and crustaceans (Croker 1962; Patillo et al. 1997). 

Patillo et al. (1997) indicated that only adults and juvenile stages occur within Matagorda Bay 

and that even these stages are rare.

Red Drum. Red drum (Sciaenops ocellatus) occur throughout the Gulf of Mexico in shallow 

estuarine waters up to about 40 m (130 ft) off shore. They inhabit a variety of substrates, 

including seagrass, sand, mud, and oyster reefs, and can tolerate freshwater through high 

salinity waters. Red drum move to deep offshore waters in the fall where they spawn in inlet 

and bay mouths. Eggs hatch in the Gulf, and larvae make their way into estuaries where they 

remain until maturity. Larvae feed exclusively on mysids, amphipods, and shrimp. Juveniles 

most often inhabit shallow, protected waters with grassy or muddy bottoms and feed on crabs, 

shrimp, and small fish. As red drum grow, they shift more of their diet to crabs and eat less fish. 

Predators include many larger fish species, such as spot (Leiostomus xanthrus) and Atlantic 

croaker (Micropogon undulates), sharks, amberjacks (Seriola spp.), and other large piscivorous 

fish. Patillo et al. (1997) indicated that all life stages of red drum were common in Matagorda 

Bay.

Brown, White, and Pink Shrimp. Brown shrimp (Farfantepenaeus aztecus) inhabit rivers, 

estuaries, and offshore Gulf waters to depths of 100 m (330 ft). Adults spawn in spring and 

summer months in waters at least 18 m deep and of temperatures between 17 and 29 °C 

(63 to 84 °F). Eggs are demersal, and larvae are pelagic and feed on planktonic algae and 

zooplankton. On flood tides, larvae and juveniles move into estuaries with shallow waters and 

submerged aquatic vegetation. They are tolerant of a wide-range of salinities and have been 

recorded as occurring in waters from 0 to 70 ppt. Adults inhabit Gulf waters from mean low tide 

to the continental shelf in areas with silt, muddy sand, or sandy substrate.

White shrimp (Litopenaeus setiferus) inhabit shallower waters than brown shrimp—generally 

only out to a depth of 40 m (130 ft) but most often less than 27 m (89 ft). They spawn in waters 

of 9 to 34 m (30 to 110 ft) in spring, summer, and fall. On flood tides, larvae and juveniles move 

into estuaries with muddy or peat bottoms and significant amounts of detritus. Juvenile white 

shrimp are often more highly associated with marsh edges, and they feed on sand, detritus, 

organic matter, mollusk fragments, ostracods, copepods, and insect larvae. Similar to brown 

shrimp, white shrimp emigrate from rivers and estuaries to deeper Gulf waters as adults.

Pink shrimp (Farfantepenaeus duorarum) occupy deeper waters (up to 110 m (360 ft)) than 

either the brown or white shrimp. They spawn year-round at depths of 22 to 47 m (72 to 150 ft) 

and temperatures from 19.6 to 30.6 °C (67.3 to 87.1 °F). Post-larvae migrate to estuaries on 
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the flood tides at night in the spring and fall. They inhabit seagrass and mangrove habitats 

where they burrow into sand and shell mud substrate and return to the water column to feed at 

night. Juveniles eat a wide variety of organisms, including red and blue-green algae, diatoms, 

dinoflagellates, polychaetes, nematodes, shrimp, mysids, copepods, isopods, amphipods, 

mollusks, forams, and fish. Adults move from estuaries into Gulf waters with sand and shell 

substrate. They are most abundant in waters with depths of 9 to 48 m (30 to 160 ft). 

Gulf Stone Crab. The Gulf stone crab (Menippe adina) occupies bottom habitats from less than 

1 m (3 ft) (shoreline) to depths of 61 m (200 ft). Adults seek out habitat in which they can 

burrow under the surface, including rock ledges, coral heads, seagrass patches, oyster bars, 

rock jetties, and artificial reefs. Adults feed mainly on oysters (Wilber 1989). Females maintain 

eggs on their abdomen until they hatch and become planktonic. As they metamorphose to 

larvae, they become epibenthic and settle to areas providing cover such as rubble and seagrass 

beds. Juveniles inhabit the bottom of the water column but do not burrow. Both adults and 

juveniles can tolerate salinities up to 33 ppt. Juveniles feed on small mollusks, worms, and 

crustaceans. Larvae require higher salinities of 30 to 35 ppt and warm water (greater than 

86 °F (30 °C)) for optimum growth and survival. All life stages of Gulf stone crab are considered 

common throughout the year in Matagorda Bay (Patillo et al. 1997).

EFH Species Identified During STP Aquatic Studies. This section briefly discusses EFH 

species in STP aquatic studies. Section 4.5 discusses these studies in detail. Of the nine 

species with designated EFH, two species (brown and white shrimp) have appeared in STP 

impingement or entrainment samples. ENSR (2008a) collected mangrove snapper via gill net, 

but this species has not appeared in impingement or entrainment samples. Additionally, 

ENSR (2008a) observed red drum, but ENSR did not collect this species in impingement and 

entrainment samples or with any of the sample gears.

McAden et al. (1984, 1985) conducted studies to estimate entrainment impacts by collecting 

surface plankton samples in front of the RMPF. McAden et al. (1984, 1985) also conducted 

impingement studies by washing all organisms off two intake screens and filtering them through 

a dip net. Section 4.5 discusses this study’s methods in more detail. McAden et al. undertook 

this study to confirm the accuracy of pre-operational entrainment and impingement loss 

predictions for 1975 through 1976. McAden (1984) collected the post-larval stage of brown and 

white shrimp sporadically in very low densities. Post-larval white and brown shrimp appeared in 

Colorado River plankton net, trawl, and seine samples sporadically and in very low densities 

(McAden et al. 1983). McAden et al. (1983, 1984) also collected white shrimp in plankton net 

samples in the siltation basin. White shrimp appeared in impingement samples in both 1983 

(16 individuals) and 1984 (4 individuals) in very low numbers (McAden et al. 1983, 1984). 

Brown shrimp did not appear in impingement samples in either year.

In 2007 and 2008, ENSR (2008a) conducted impingement and entrainment studies at the CWIS 

on the MCR from May 2007 through April 2008 as part of the STP, Units 3 and 4, COL 

application. Section 4.5 discusses this study’s methods. During the study, ENSR (2008a) 

collected two mangrove snappers via gill net in the MCR. In October 2007, mangrove snappers 

accounted for 2 percent of the fish in trawl samples. The species was not present, or accounted 

for less than 1 percent of trawl samples, for all other sample months. ENSR noted that several 

large schools of red drum were observed during the study, but none were collected in any of the 

sample gears during the study. Of the shrimp species, ENSR (2008a) collected white shrimp 

and brown shrimp in entrainment samples. These species made up 3 percent and less 

than 1 percent of total samples, respectively. ENSR did not collect any king mackerel, Spanish 

mackerel, pink shrimp, or Gulf stone crab in any of the study samples.
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2.2.8.7 Species Protected Under State of Texas Statutes

The Texas legislature authorized the TPWD to establish a list of State-endangered species 

in 1973, for animals, and in 1988, for plants. Title 5, Wildlife and Plant Conservation, 

Chapter 68, Endangered Species, of the State of Texas’s Statutes prohibits individuals from 

capturing, trapping, taking, or killing as well as possessing, selling, or distributing listed animal 

species. Chapter 88, Endangered Plants, prohibits individuals from collecting or selling listed 

plants obtained from public land without a TPWD-issued permit. Table 2–11 contains 

State-listed species that have the potential to occur on the STP site or along the transmission 

line corridors. Additionally, all Federally listed species that appear in Table 2–9 are 

State-protected as well.

Table 2–11. State-listed Species

Potential 

Occurrence(b)

Species Common Name State 

Status(a) Onsite Along Tline ROWs

Amphibians 

Eurycea latitans Cascade Caverns salamander T x

Eurycea tridentifera comal blind salamander T x

Birds 

Buteo albicaudatus white-tailed hawk T x x

Buteo albonotatus zone-tailed hawk T x

Egretta rufescens reddish egret T x x

Falco peregrinus anatum American peregrin falcon T x x

Falco peregrinus tundrius arctic peregrin falcon T x x

Haliaeetus leucocephalus bald eagle T x x

Mycteria americana wood stork T x x

Pelecanus occidentalis brown pelican E x x

Plegadis chihi white-faced ibis T x x

Sterna fuscata sooty tern T x x

Fish

Cycleptus elongatus blue sucker T x x

Satan eurystomus widemouth blindcat T x

Trogloglanis pattersoni toothless blindcat T x

Mollusks

Lampsilis bracteata Texas fatmucket T x

Quadrula aurea golden orb T x

Quadrula houstonensis smooth pimpleback T x x
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Potential 

Occurrence(b)

Species Common Name State 

Status(a) Onsite Along Tline ROWs

Quadrula petrina Texas pimpleback T x

Truncilla macrodon Texas fawnsfoot T x

Reptiles

Cemophora coccinea lineri Texas scarlet snake T x x

Crotalus horridus timber (canebrake) rattlesnake T x x

Drymarchon melanurus 

erebennus Texas indigo snake T x 

Gopherus berlandieri Texas tortoise T x x

Liochlorophis vernalis smooth green snake T x

Macrochelys temminckii alligator snapping turtle T x

Phrynosoma cornutum Texas horned lizard T x x

(a) E=endangered; T=threatened

(b) The STP site is located in Matagorda County. The transmission lines associated with the STP site traverse 

Matagorda County as well as Bexar, Brazoria, Colorado, DeWitt, Fayette, Gonzales, Guadalupe, Jackson, Lavaca, 

Wharton, and Wilson Counties.

Sources: NRC 2011b; STPNOC 2010b; TPWD 2011c, 2011f

2.2.9 Socioeconomics

This section describes current socioeconomic factors that have the potential to be directly or 

indirectly affected by changes in operations at STP, Units 1 and 2. STP, and the communities 

that support it, can be described as a dynamic socioeconomic system. The communities 

provide the people, goods, and services required to operate the nuclear power plant. Power 

plant operations, in turn, provide wages and benefits for people and dollar expenditures for 

goods and services. The measure of a communities’ ability to support STP, Units 1 and 2, 

operations depends on the ability of the community to respond to changing environmental, 

social, economic, and demographic conditions.

The socioeconomics region of influence (ROI) is defined by the area where STP, Units 1 and 2, 

employees and their families reside, spend their income, and use their benefits, thereby 

affecting the economic conditions of the region. The ROI consists of a two-county area 

(Brazoria and Matagorda Counties), where approximately 84 percent of STP employees reside.

STPNOC employs a permanent workforce of approximately 1,378 workers at STP, Units 1 

and 2, with approximately 84 percent living in Brazoria and Matagorda Counties (see

Table 2–12) (STPNOC 2010b). Of the remaining 16 percent of the workforce, most are divided 

among 18 counties across Texas and other states, with numbers ranging from 1 to 

62 employees per county. Given the residential locations of STP, Units 1 and 2, employees, the 

most significant impacts of plant operations are likely to occur in Brazoria and Matagorda 

Counties. The focus of the socioeconomic impact analysis in this SEIS is, therefore, on the 

impacts of continued STP, Units 1 and 2, operations on these two counties.
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Table 2–12. STP, Employee Residence by County

County # of Employees % of Total

Brazoria 298 22

Matagorda 851 62

Fort Bend 54 4

Wharton 62 4

Other 96 7

Other states 17 1

Total 1,378 100

Source: STPNOC 2010b 

Refueling outages at STP, Units 1 and 2, normally occur at 18-month intervals. During refueling 

outages, site employment increases by as many as 1,350 temporary workers for approximately 

1 to 2 months (STPNOC 2010b). Most of these workers are assumed to be located in the same 

geographic areas as STP, Units 1 and 2, employees. The following sections describe the 

housing, public services, offsite land use, visual aesthetics and noise, population demography, 

and the economy in the ROI surrounding STP, Units 1 and 2. 

2.2.9.1 Housing

Table 2–13 lists the total number of occupied and vacant housing units, vacancy rates, and 

median value in the two-county ROI. According to American Community Survey, there were 

approximately 138,000 housing units in the socioeconomic region, of which approximately 

117,000 were occupied. The median value of owner-occupied housing units in Brazoria and 

Matagorda Counties were $146,700 and $90,400 respectively. Brazoria County had a lower 

vacancy rate (12.6 percent) than Matagorda County, which had a 27.9 percent vacancy rate 

(USCB 2011).

Table 2–13. Housing in Brazoria and Matagorda Counties in 2010

Brazoria Matagorda ROI

Total units 118,813 18,827 137,640

Occupied housing units 103,828 13,568 117,396

Vacant units 14,985 5,259 20,244

Vacancy rate (%) 12.6 27.9 14.7

Median value ($)* 146,700 90,400 118,550

Key: * estimated

Source: USCB 2010

2.2.9.2 Public Services

Water Supply. Brazoria and Matagorda Counties are located in southeastern Texas. 

Information about municipal water suppliers in these counties, their permitted capacities or 

maximum design yields or both, reported annual peak usage, and population served are 

presented in Table 2–14. The Texas TWDB divided Texas into 16 water-planning regions 
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(Region A through Region P). Brazoria County is located in Region H, while Matagorda County 

is located in Region K. 

Brazoria County is 1 of 15 counties located in Region H, which includes the Houston 

metropolitan area. Over 20 percent of the State’s 2010 population resides in Region H. As 

seen in Table 2–14, the city of Pearland serves the largest population at 56,877 and has the 

highest average daily consumption (11.0 mgd), while the city of Clute serves the smallest at 

10,737 and has the lowest average daily consumption (0.361 mgd). Alvin serves 15 less people 

than Angleton but consumes slightly more water daily (EPA 2010).

Matagorda County is 1 of 14 counties located in Region K. Bay City, located approximately 

19.5 mi (31.4 km) north-northeast of STP, serves a population of 19,263 from a groundwater 

source with an average daily consumption of 2.41 mgd (EPA 2010).

STP withdraws potable water primarily from the deep-confined aquifer within the Beaumont 

Fountain. In 2009, STP withdrew 368,766,200 gal (1,395,931,917.5 liters) of water from five 

active onsite groundwater wells, of which 5 percent was used for sanitary and drinking 

purposes. STPNOC is permitted to withdraw an average of 2.7 mgd (STPNOC 2010b). 

Table 2–14. Brazoria and Matagorda County City Public Water 

Supply Systems (in mgd)

Water Supplier

Primary Water 

Source

Average Daily

Demand (mgd)

System

Capacity (mgd)

Population

Served

Brazoria County

Alvin GW 2.18 8.74 19,152

Angleton SW 2.05 5.47 19,167

Clute SW 0.36 2.08 10,373

Freeport SW 1.40 0.00 (production vs. 

purchased) 12,708

Lake Jackson SW 3.10 6.69 25,890

Pearland SW 11.00 15,26 56,877

Matagorda County

Bay City GW 2.41 8.86 19,263

Surface Water = SW, Groundwater = GW

Source: EPA 2010

Education. Brazoria County has eight school districts consisting of 4 pre-kindergarten, 

43 elementary, 23 middle/junior high/intermediate, 15 high schools, 10 alternative, 1 charter, 

and 1 grade 9 school. During the 2009 to 2010 school year, enrollment was 60,251 

(NCES 2011).

Matagorda County has five districts consisting of 8 pre-kindergarten, 8 elementary, 

4 middle/junior high/intermediate, 4 high schools, and 1 alternative school. During the 2009 to 

2010 school year, enrollment was 7,185 (NCES 2011).

Transportation. STP is located in an area severed by U.S. highways, FMs, and county roads. 

Within 50 mi of STP, there are no interstate highways; however, there are two U.S. highways 

(U.S. 59 and U.S. 87). U.S. 59 runs northeast to southwest connecting Fort Bend, Wharton, 
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Jackson, and Victoria Counties. U.S. 87 runs northwest to southeast connecting Victoria and 

Calhoun County.

STP can be accessed by FM 521, which runs east and west. FM 521 is accessible by several 

FM and State highways, which would be most commonly commuted by STP workers. Workers 

traveling from the east side of Matagorda County and all of Brazoria County would likely take 

TX-60 south and exit at FM 521. Workers commuting from the north would likely travel on 

TX-35 west, exiting on to FM 1468 south or FM 1095 south. Workers arriving from the west are 

likely to travel on TX-35 east, exiting onto FM 521 east. 

Table 2–15 lists commuting routes to STP and average annual daily traffic (AADT) volume 

values. The AADT values represent traffic volumes for a 24-hour period factored by both day of 

week and month of year.

Table 2–15. Major Commuting Routes in the Vicinity of STP, 2010 AADT

Roadway & Location AADT (a)

TX-60 South from Bay City to FM 521 West 2,400–3,000

FM 2078 West to FM 2668 South 310

FM 2668 South from Bay City to FM 521 West 1,050–2,200

FM 1468 South from TX-35 to FM 521 East 700–940

FM 1095 South from TX-35 to FM 521 East 390–630

FM 2853 South to FM 521 East 510–580

FM 521 West from TX-60 1,600–2,500

FM 521 East from FM 1095 1,150

(a) All AADTs represent traffic volume during the average 24-hour day during 2010.

Key: FM = Farm-to-Market; TX = Texas 

Source: TXDOT 2011

2.2.9.3 Offsite Land Use

Offsite land use conditions in Brazoria and Matagorda Counties are described in this section. 

Approximately 84 percent of the STP permanent workforce lives in these two counties. Within 

the region of STP, approximately 61 percent of the land is agricultural, 18 percent forest, 

10 percent rangeland, 5 percent wetland, 2.5 percent urban or developed land, 2 percent

freshwater bodies, and less than 1 percent barren land (STPNOC 2010d). 

Brazoria County occupies approximately 1,350 mi2 (3,496 km2

) (USCB 2010). Agricultural land 

is principally used as pasture (52.8 percent) and cropland (35.2 percent). Livestock (mostly 

cattle and calves) comprise 45 percent of the total market value of agricultural products 

(livestock and crop product) sold in the county while crop sales comprise the remaining 

55 percent (mostly grains, dry beans and peas, nursery, and floriculture). The number of farms 

in Brazoria increased about 5 percent from 2002 to 2007. Farmland acreage in the county 

decreased 14 percent during the same period, and the average size of a farm decreased 

18 percent to 205 ac (82 ha) (NASS 2009).

Matagorda County occupies approximately 1,100 mi2 (2,849 km2

) (USCB 2010). Agricultural 

land is principally used as pasture (51.08 percent) and cropland (40.63 percent). Crop sales 

(mostly nursery, greenhouse, floriculture, and sod) comprise 57 percent of the market value of 
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agricultural products sold from Matagorda County. Livestock sales (agricultural products of 

mostly cattle and calves) comprise the remaining 43 percent. The number of farms in 

Matagorda County decreased from 2002 to 2007 by 9 percent. The number of farmland acres 

decreased by 7 percent; however, the average size of farms increased by 2 percent from 625 ac 

to 640 ac (NASS 2009).

Even though population growth is projected to continue, there is ample urban and rural land to 

accommodate the anticipated growth over the next 20 years. However, agriculture will continue 

to be the major land use outside urban areas.

2.2.9.4 Visual Aesthetics and Noise

The STP site boundary encloses approximately 

12,220 ac, with site buildings, operations area, 

support facilities, and transmission ROWs

occupying approximately 65 ac. Approximately 

7,046 ac are occupied by other STP features, the 

ECP, and the MCR (STPNOC 2010b). 

The site includes approximately 1,700 ac of 

undeveloped natural lowland habitat, with characteristics of the Texas Coastal Plain Province, 

and the land surrounding the site is used for ranchland and farmland (STPNOC 2010b). STP is 

situated on low elevation, generally less than 60 feet MSL, with open prairie habitat interspersed 

with creek and river drainages flowing toward the Gulf coasts marshes. Trees are rare but can 

be found along streams and in oak groves (STPNOC 2010d). Given the flat nature of the land, 

the STP reactors are a prominent feature of the area, and the MCR is visible from the southeast 

along the Colorado River as well as other points around the site.

Noise from nuclear plant operations can be detected off site. Sources of noise at STP include 

the turbines and large pump motors. Given the industrial nature of the station, noise emissions 

from the station are generally nothing more than an intermittent minor nuisance. However, 

noise levels may sometimes exceed the 55 dBA level that EPA uses as a threshold level to 

protect against excess noise during outdoor activities (EPA 1974). However, according to EPA, 

this threshold does “not constitute a standard, specification, or regulation,” but it was intended to 

provide a basis for State and local governments establishing noise standards.

2.2.9.5 Demography

According to 2000 Census information, an estimated 35,291 people lived within 20 mi (32 km) of 

STP, which equates to a population density of 36 persons per square mile (STPNOC 2010b). 

This translates to a Category 1, “most sparse,” population density using the GEIS measure of 

sparseness (i.e., less than 40 persons per square mile and no community with 25,000 or more 

people within 20 mi). Based on the GEIS proximity matrix, the STP proximity population density 

is classified as Category 2 (no city with 100,000 or more people and less than 50 persons per 

square mile within 50 mi). Therefore, with STP regional population classifications of sparseness 

Category 1 and proximity Category 2, STP lies in a low-population area.

Table 2–16 shows population projections and growth rates from 1970 to 2050 in Brazoria and 

Matagorda Counties in Texas. The growth rate in Brazoria County showed an increase in 

population of nearly 30 percent between 2000 and 2010. Conversely, Matagorda County 

showed a 3.3 percent decrease in population between 2000 and 2010. Both county populations 

are projected to increase each decade through 2050. 

The EPA generally uses 55 decibels (dBA) as the 

noise threshold level to protect against excess 

noise during outdoor activities. However, 

according to EPA, this threshold does “not 

constitute a standard, specification, or regulation,” 

but it was intended to provide a basis for State 

and local governments establishing noise 

standards.
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Table 2–16. Population and Percent Growth in Brazoria and Matagorda Counties 

from 1970 to 2010 and Projected for 2020 to 2050

Year Brazoria % Change Matagorda % Change

1970 108,312 N/A 27,913 N/A

1980 169,587 56.6 37,828 35.5

1990 191,707 13.0 36,928 -2.4

2000 241,767 26.1 37,957 2.8

2010 313,166 29.5 36,702 -3.3

2020 349,474 11.6 40,789 11.1

2030 397,663 13.8 42,559 4.3

2040 445,852 12.1 44,330 4.2

2050 494,041 10.8 46,101 4.0

Source: USCB (2011) provided the population data for 1970 through 2010. The data forecast for 2020 through 2050

was calculated. 

Demographic Profile. The 2010 demographic profiles of the two-county ROI population are

presented in Table 2–17. In 2010, minorities (race and ethnicity combined) comprised 

47.4 percent of the total two-county population. The minority population is largely Hispanic or 

Latino (28.8 percent) with the next largest minority population being Black or African American 

(11.7 percent). 

Table 2–17. Demographic Profile of the Population in the 

STP Two-County Socioeconomic ROI in 2010

Brazoria Matagorda ROI

Total population 313,166 36,702 349,868

Race (not Hispanic or Latino)—% of total population

White 53.2 47.4 52.6

Black or African American 11.8 11.1 11.7

American Indian & Alaska Native 0.3 0.3 0.3

Asian 5.4 1.9 5.1

Native Hawaiian & Other Pacific Islander 0.0 0.0 0.0

Some other race 0.2 0.1 0.1

Two or more races 1.4 0.9 1.4

Ethnicity

Hispanic or Latino 86,646 14,047 100,717

% of total population 27.7 38.3 28.8

Total minority 146,492 19,302 165,794
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Brazoria Matagorda ROI

% minority 46.8 52.6 47.4

Source: USCB 2010

Transient Population. Within 50 mi (80 km) of STP, colleges and recreational opportunities 

attract daily and seasonal visitors who create demand for temporary housing and services. In

2010, there were approximately 11,118 students attending colleges and universities within 50 mi 

(80 km) of STP (IES 2010).

In 2000, 1.7 percent of all housing units were considered temporary housing for seasonal, 

recreational, or occasional use in Brazoria County. By comparison, seasonal housing 

accounted for 12.9 percent of total housing units in Matagorda County (USCB 2010). Calhoun 

and Jackson Counties have the highest percent of temporary housing for seasonal, recreational, 

or occasional use, at 17.1 and 18.5 percent, respectively (USCB 2010). Table 2–18 provides 

information on seasonal housing for the nine counties located all or partly within 50 mi of STP.

Table 2–18. Seasonal Housing in Counties Located within 50 mi of STP 

County (a) Housing Units

Vacant Housing Units: For Seasonal, 

Recreational, or Occasional Use % 

Texas

Brazoria 90,628 1,496 1.7

Calhoun 10,238 1,757 17.1

Colorado 9,431 634 6.7

Fort Bend 115,991 5,076 4.4

Jackson 6,545 1,209 18.5

Lavaca 9,657 377 3.9

Matagorda 18,611 2,407 12.9

Victoria 32,945 261 0.8

Wharton 16,606 291 1.8

Total 310,652 13,508 7.5

(a) Counties within 50 mi (80 km) of STP with at least one block group located within the 50-mi (80 km) radius 

Source: USCB 2010

Migrant Farm Workers. Migrant farm workers are individuals whose employment requires travel 

to harvest agricultural crops. These workers may or may not have a permanent residence. 

Some migrant workers follow the harvesting of crops, particularly fruit, throughout rural areas of 

the U.S. Others may be permanent residents near the STP site who travel from farm to farm 

harvesting crops.

Migrant workers may be members of minority or low-income populations. Because they travel 

and can spend a significant amount of time in an area without being actual residents, migrant 

workers may be unavailable for counting by census takers. If uncounted, these workers would 

be “underrepresented” in USCB minority and low-income population counts.
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Information on migrant farm and temporary labor was collected in the 2007 Census of 

Agriculture. Table 2–19 provides information on migrant farm workers and temporary farm labor 

(less than 150 days) within 50 mi of the STP. According to the 2007 Census of Agriculture, 

approximately 6,513 farm workers were hired to work for less than 150 days and were 

employed on 2,233 farms within 50 mi of the STP. The county with the largest number of 

temporary farm workers (1,176) on 396 farms was Wharton County, Texas (NASS 2011).

In the 2002 Census of Agriculture, farm operators were asked for the first time whether or not 

they hired any migrant workers, defined as a farm worker whose employment required travel 

that prevented the migrant worker from returning to his or her permanent place of residence the 

same day. In the 50-mi radius of STP, 185 farms reported hiring migrant workers in the 2007 

Census of Agriculture. Lavaca and Wharton Counties reported the most farms (35 and 31, 

respectively) with hired migrant workers, followed by Brazoria and Fort Bend County, with 

28 and 25 farms, respectively (NASS 2011).

According to the 2007 Census of Agriculture estimates, 1,001 temporary farm workers (those 

working fewer than 150 days per year) were employed on 414 farms in Brazoria County, and 

754 temporary farm workers were employed on 247 farms in Matagorda County, respectively 

(NASS 2011).

Table 2–19. Migrant Farm Workers and Temporary Farm Labor in Counties 

Located within 50 mi of STP 

County (a)

Number of Farms 

with Hired Farm 

Labor (b)

Number of Farms 

Hiring Workers for 

Less Than 150 Days (b)

Number of Farm 

Workers Working for 

Less Than 150 days 

(b)

Number of Farms 

Reporting 

Migrant Farm 

Labor (b)

Texas

Brazoria 414 332 1,001 28

Calhoun 66 54 143 4

Colorado 372 319 853 23

Fort Bend 299 230 621 25

Jackson 200 164 408 12

Lavaca 475 410 925 35

Matagorda 247 208 754 16

Victoria 252 216 632 11

Wharton 396 300 1,176 31

Total 2,721 2,233 6,513 185

(a) Counties within 50 mi of STP with at least one block group located within the 50-mi radius

(b) Table 7. Hired Farm Labor—Workers and Payroll: 2007 Census of Agriculture

Source: NASS 2009

2.2.9.6 Economy

Employment and Income. Between 2000 and 2010, the civilian labor force in Brazoria County 

increased 34.5 percent from 112,798 to 151,791. Matagorda County also increased during that 
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time, 5.6 percent from 16,434 to 17,365 (USCB 2010). Major industries in Matagorda County 

are presented in Table 2–20. 

According to 2008 through 2010 American Community Survey 3-Year Estimates, educational, 

health, and social services industry employs the most workers in the socioeconomic ROI 

(22.5 percent) followed by wholesale trade (16.7 percent). A list of employment by industry in 

the ROI is presented in Table 2–21. 

Table 2–20. Major Industries in Matagorda County

Company Name Type of Business

STPNOC Electricity generation

Lyondell Basell High density polyethylene resins

Valerus Compressors Compressor fabrication

McAda Drilling Fluids Oilfield support

OXEA Corporation Chemical products

Celanese Chemical products

Henderson Fabrication Steel fabrication

Source: Matagorda County EDC 2007

Table 2–21. Major Industries in ROI

Industry Brazoria Matagorda Total %

Total employed civilian workers 142,741 15,080 157,821

Agriculture, forestry, fishing & hunting, & mining 3,677 1,560 5,237 3.3

Construction 14,889 1,274 16,163 10.2

Manufacturing 17,962 1,422 19,384 12.3

Wholesale trade 4,638 310 26,299 16.7

Retail trade 13,694 2,273 15,967 10.1

Transportation, warehousing, & utilities 7,362 1,643 9,005 3.8

Information 2,382 219 2,601 1.6

Finance, insurance, real estate, rental, & leasing 7,061 458 7,519 4.8

Professional, scientific, management, 

administrative, & waste management services 15,182 812 15,994 10.1

Educational, health, & social services 32,613 2,887 35,500 22.5

Arts, entertainment, recreation, 

accommodation, & food services 9,196 960 10,156 6.4

Other services (except public administration) 7,758 802 8,560 5.4

Public administration 6,057 460 6,517 4.1

Source: USCB 2010 
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Estimated income information for the STP ROI is presented in Table 2–22. According to the 

USCB, people living in Brazoria County had a higher median household and per capita income 

than the State average, while Matagorda had a lower median household and per capita income 

(UCSB 2010). An estimated 10.6 and 19.2 percent of the population in Brazoria and Matagorda 

Counties were living below the official poverty level, respectively. The State of Texas as a 

whole had a higher percentage of persons living below the poverty level (17 percent) than 

Brazoria County, but lower than Matagorda County. The percentage of families living below the 

poverty level in Brazoria County (8.2 percent) was lower than the State of Texas average 

(13.2 percent), but Matagorda County (17.4 percent) was higher than the State average 

(UCSB 2010).

Table 2–22. Estimated Income Information for STP ROI

Brazoria Matagorda Texas

Median household income (dollars) (a) 66,221 41,586 49,585

Per capita income (dollars) (a) 27,381 23,138 24,671

Individuals living below the poverty level (percent) 10.6 19.2 17

Families living below the poverty level (percent) 8.2 17.4 13.2

(a) In 2008 inflation-adjusted dollars

Source: USCB 2011

Unemployment. According to the USCB’s 2006 through 2008 American Community Survey 

3-Year Estimates, the unemployment rates in Brazoria and Matagorda Counties were 4.0 and 

8.1 percent, respectively, in comparison to the unemployment rate of 4.8 percent for the State of 

Texas (USCB 2010).

Taxes. All privately owned property in Texas is subject to taxation by the county and school 

district in which it is located, unless specifically exempted by the Texas Constitution. Most 

private property owners in Texas also pay property taxes to local jurisdictions like cities and 

special districts within whose boundaries they reside. As such, property tax revenues are the 

major tax revenue source for counties and cities and the sole source of tax revenue for school 

districts. Exemptions from these standard practices are governed by the State, while county 

appraisal districts determine the value of properties with local jurisdictions setting the tax rates. 

After assessment, private property owners then make a consolidated payment to the County 

Tax Assessor, who retains the county’s portion and distributes the special district funds to the 

special districts, as appropriate (STPNOC 2010b). 

STPNOC, owner of STP, Units 1 and 2, pays the majority of property taxes to the following 

taxing jurisdictions: Matagorda County, Matagorda County Hospital District, Navigation 

District #1, Drainage District #3, Palacios Seawall District, and the Coastal Plains Groundwater 

District (STPNOC 2010b). Table 2–23 presents each district’s total property tax levies, STP 

payments, and the proportion of the total constituted by STP. STP payments represent a major 

portion of property tax revenues for each of the districts, ranging from 22 percent to 75 percent

in the various districts from 2004 to 2008. From 2003 to 2007, in Matagorda County specifically 

(excluding special districts within the county), STP property tax payments to Matagorda County 

alone have represented approximately one-third of the county’s total revenues (total revenues 

include property tax payments and other sources). In 2001, STPNOC negotiated an agreement 

with Matagorda County (to begin in 2002) to remit a county service fee in lieu of property taxes 

to the county, with a revenue cap of $6.1 million. STPNOC has a similar agreement with the 
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local hospital district, capped at $2.6 million, to compensate the hospital for its extensive 

support of STPNOC’s emergency response requirements (STPNOC 2010b). 

Table 2–23. Comparison of STP Owner Payments with Taxing District Property Tax

Year(a) Taxing District Property Tax Levy($) (b)

Total STP

Payments($) (c)

% of Property Tax 

Levy

2003 Matagorda County (d) 8,214,934 6,100,000 74.3

Matagorda County

Hospital(d) 4,126,692 2,461,132 59.6

Navigation District #1 459,261 360,394 78.5

Drainage District #3 288,179 249,859 86.7

Palacios Seawall 499,121 411,000 82.3

Coastal Plains 

Groundwater 137,930 45,264 32.8

Total 13,726,117 9,627,649 70.1

2004 Matagorda County(d) 8,122,946 6,100,000 75.1

Matagorda County 

Hospital(d) 5,254,940 2,526,807 48.1

Navigation District #1 413,867 360,410 87.1

Drainage District #3 287,909 249,869 86.8

Palacios Seawall 433,674 411,018 94.8

Coastal Plains 

Groundwater 136,040 45,266 33.3

Total 14,649,376 9,693,370 66.2

2005 Matagorda County(d) 8,191,213 6,100,000 74.5

Matagorda County 

Hospital(d) 5,613,566 2,343,558 41.7

Navigation District #1 370,191 251,822 68.0

Drainage District #3 254,311 203,684 80.1

Palacios Seawall 329,155 223,926 68.0

Coastal Plains 

Groundwater 141,239 31,628 22.4

Total 14,899,675 9,154,618 61.4

2006 Matagorda County(d) 9,038,864 6,100,000 67.5

Matagorda County 

Hospital(d) 5,753,331 2,567,253 44.6

Navigation District #1 486,645 342,148 70.3
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Year(a) Taxing District Property Tax Levy($) (b)

Total STP

Payments($) (c)

% of Property Tax 

Levy

Drainage District #3 242,142 200,299 82.7

Palacios Seawall 327,813 230,162 70.2

Coastal Plains 

Groundwater 153,850 39,422 25.6

Total 16,002,645 9,479,284 59.2

2007 Matagorda County(d) 9,785,561 6,100,000 62.3

Matagorda County 

Hospital(d) 6,236,490 2,600,000 41.7

Navigation District #1 519,472 377,347 72.6

Drainage District #3 229,254 190,125 82.9

Palacios Seawall 276,122 200,131 72.5

Coastal Plains 

Groundwater 166,556 45,019 27.0

Total 17,213,455 9,512,622 55.3

2008 Matagorda County(d) 10,968,961 6,100,000 55.6

Matagorda County 

Hospital(d) 7,035,468 2,600,000 37.0

Navigation District #1 547,517 405,019 74.0

Drainage District #3 246,398 202,883 82.3

Palacios Seawall 276,565 203,844 73.7

Coastal Plains 

Groundwater 187,828 48,454 25.8

Total 19,262,737 9,560,200 49.6

6-Year Total 95,754,005 57,027,743 59.6

(a) Year levy and rate are for the following budget year. STP, Units 1 and 2, owners pay the standard millage rate for 

the special districts.

(b) Total levies for 2003–2007 are from the Texas Comptroller of Public Accounts, Annual Property Tax Reports for 

Tax Years 2003, 2004, 2005, and 2006, as well as 2007 Property Tax Rates and Taxes. Total levies for 2008 are 

from the Matagorda County Tax Office.

(c) For 2003–2006, tax payments are based on estimates from the Matagorda County Tax Office. For 2007 and 

2008, estimated payments are based on actual NRG property tax statements.

(d) Payments to Matagorda County and the Matagorda County Hospital District are based on an agreement between 

those entities and STPNOC, which sets a fixed amount to be paid each year.

Note: Totals may not add due to rounding.

Source: STPNOC 2010b 
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In addition to tax payments to the districts discussed above, STP pays taxes to other districts 

within Matagorda County for undeveloped portions of the STP plant site that lie within other 

taxing districts and for other STP-related property within the county. The receiving districts are

the Port of Bay City Conservation and Reclamation District, Drainage Districts 1 and 2, and the 

City of Bay City. Per State of Texas tax law, STP also pays taxes to three of the five 

independent school districts (ISDs) in Matagorda County—Matagorda, Bay City, and Tidehaven. 

Table 2–24 shows these payments. These payments represent a small proportion of those 

districts’ total levies in comparison to the percentages of the main district payments shown 

above.

Table 2–24. STP, Units 1 and 2, Owner Payments to Other Taxing Districts in Matagorda

 2007 2008

Special District (a)

STP Owner 

Payments ($)

District’s Est. 

Total Levy, 

2007 ($)

STP as 

% of 

Total

STP Owner 

Payments

($)

District’s 

Est. Total 

Levy, 2008

($)

STP as 

% of 

Total 

Port of Bay City 3,097 723,680 0.43 5,080 388,907 0.61

Conservation & 

Reclamation District 468 112,458 0.42 774 130,055 0.60

Matagorda ISD 74,943 2,525,549 2.97 75,038 2,677,920 2.80

Drainage District #1 6,419 1,607,005 0.40 6,179 1,681,062 0.37

Drainage District #2 2,000 342,514 0.58 6,278 419,134 1.50

Bay City ISD 0 12,840,989 - 1,942 14,265,846 0.01

Tidehaven ISD 22,837 5,029,792 0.45 79,465 6,541,043 1.21

City of Bay City 0 2,746,295 - 747 3,050,691 0.02

Total 111,771 25,925,282 0.43 175,502 29,599,657 0.59

(a) “Other” = Taxing districts (Special District) other than Matagorda County; Matagorda County Hospital; Navigation 

District #1; Palacios Seawall District; Coastal Plains Groundwater District; and Drainage District #3.

Source: STPNOC 2010b 

STP is located in the Electric Reliability Council of Texas region, a deregulated area that is not 

set to change in the foreseeable future. As such, STPNOC’s future taxation will continue to be 

based on the market value of the site and agreements with the county regarding service fees in 

lieu of property taxes (STPNOC 2010b). 

2.2.10 Historic and Archaeological Resources

In accordance with 36 CFR 800.8(c), the NRC has elected to use the National Environmental 

Policy Act of 1969, as amended (NEPA), process to comply with the obligations under 

Section 106 of the National Historic Preservation Act (NHPA). In addition, NUREG-1555 

(NRC 2000) provides guidance to staff on how to conduct historic and cultural resource analysis 

in its environmental reviews.

In the context of NHPA, the NRC has determined that the area of potential effect (APE) for a 

license renewal action is the area at the power plant site and its immediate environment that 

may be affected by post–license renewal and land-disturbing activities associated with the 
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proposed action (NRC 2011e). The APE may extend beyond the immediate environs in 

instances where post–license renewal and land-disturbing activities or refurbishment activities 

specifically related to license renewal may potentially have an effect on historic properties 

(NRC 2011e). 

Cultural Background. Substantial archaeological records indicate that there was prehistoric 

occupation of the STP area. During the Paleoindian era (pre-7800 B.C.), the earliest inhabitants 

of Texas were the Clovis and Folsom peoples, which are typically associated with the hunting of 

the extinct mammoth and bison, respectively. The Early Archaic era (7800 B.C. to 6000 B.C.) 

represents a time when inhabitants became more settled, and numerous distinctive triangular 

points and barbed specimens are noted from this era. The Middle Archaic period (6000 B.C. 

to 2500 B.C.) reflects a diversity of stone tools and shell middens, while the Late Archaic era 

(2500 B.C. to 700 B.C.) is marked by distinctive projectile points and stone tools. The 

Late Prehistoric era (700B.C. to 1500 A.D.) is noted for the introduction of the bow and arrow 

and pottery (NRC 2011b).

Hundreds of tribes inhabited Texas, and historians have a difficult time tracing their origin 

because there are few written records from this period (University of Texas at Austin 2011). 

The historic period can be traced to the 1500s, when the Spanish and French explored the 

Texas Coast. With the arrival of the Europeans, there were many changes for the native 

peoples. Diseases destroyed many populations, and several tribes fled to and from the area 

that makes up the State of Texas today. Matagorda County was created in 1837, soon after 

Texas gained its independence from Mexico (NRC 2011b). Today, there are three indigenous 

groups living within the Texas boarders that are listed among the Nation’s many Federally 

recognized tribes—the Alabama–Coushatta Tribe in East Texas; the Ysleta del Sur Pueblo, or 

Tigua, in far West Texas; and the Kickapoo Traditional Tribe in southwest Texas along the 

Texas–Mexico border (THC 2011). Other recognized tribes maintain ties to their ancestors’ 

homelands in the State of Texas and monitor sites throughout the State that are important to 

their tribe and their history (THC 2011). Further cultural background is documented in the NRC 

EIS (2011b) for the review of the STP, Units 3 and 4, combined license application. 

Historic and Archaeological Resources at the STP Site. This section discusses the known 

historic and archaeological resources at the STP site and in the surrounding area. The 

following information was used to identify the historic and archaeological resources at the STP 

site:

• original construction FES (NRC 1975); 

• original ER (HL&P 1975), which included the Texas Archaeological Survey 

Report (Hall and Ford 1973); 

• original operation EIS (NRC 1986); 

• STP, Units 3 and 4, ER, Revision 4 (STPNOC 2010d); 

• STP, applicant’s ER, operating license renewal stage, STP, Units 1 and 2 

(STPNOC 2010b); 

• EIS for COLs for STP, Units 3 and 4 (NRC 2011b); 

• audit report regarding STP LRA—cultural resources (NRC 2011g); 

• STP, RAI responses (STPNOC 2011g); 

• consultation with THC (Texas Historical Commission); and 

• consultation with tribes.
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In the early 1970s, the Texas Archaeological Survey conducted cultural resources investigations 

of the STP site and surrounding area. The investigations included a literature review, a 

pedestrian survey, and limited subsurface testing (NRC 2011b; STPNOC 2010b, 2010d). The 

construction of STP, Units 1 and 2, was completed in the 1980s, and much of the site had been 

heavily disturbed by construction activities and the creation of the reservoir.

STP identified three cultural resource sites within 10 mi of the STP site. Cultural resources 

site 41MG48 is approximately 5 mi from the northeast boundary of the STP site and is 

described as a late 19th century artifact scatter associated with homesteading Artifacts 

consisted of ceramic, glass, and metal with manufacturing dates between 1890 and 1910. STP 

reported that a homestead was established in the 1890s and dissolved in 1946. Cultural 

resource investigations concluded that the site was not significant and that no further work on 

the site was needed.

The closest recorded site is 41MG49, and it is approximately 4 mi from the northeastern 

boundary of the STP site. Site 41MG49 was originally reported in the license renewal ER as 

having no site form record (STPNOC 2010b). In July 2011, STP revisited the information and 

discovered the missing site form record for site 41MG49 that described it as a shell midden with 

no associated artifacts(STPNOC 2011g). Cultural resource investigations concluded that the 

site was significant and should be studied further if the site were to be affected.

Site 41MG112 is approximately 5 mi from the northeastern boundary of the STP site and is 

described as a dismantled historic farmstead dating to the mid-20th century. Cultural resource 

investigations concluded that the site was not significant and that no further work on the site 

was needed (STPNOC 2011g). These three sites (41MG48, 41MG49, and 41MG112) are 

located outside of the. There are no recorded historic or archaeological resources on the STP 

site.

STP identified a potential historic gravesite in its ER (STPNOC 2010b) located on the southeast 

corner of the STP site. The NRC staff reviewed information during the environmental audit for 

cultural resources at the STP site and discussed the status and protection of the historic 

gravesite with STP environmental staff (NRC 2011g). STP staff had interviewed descendants of 

the former property owner and confirmed the presence of a historic grave from the late 1800s; 

however, this gravesite is not recorded and little is known about it (STPNOC 2011g). 

2.3 Related Federal and State Activities

The NRC reviewed the possibility that activities of other Federal agencies might impact the 

renewal of the operating license for STP. There are no Federal projects that would make it 

necessary for another Federal agency to become a cooperating agency in the preparation of 

this supplemental EIS. There are no known American Indian lands within 50 mi of STP. 

Federally owned facilities within 50 mi of STP include (NRC 2011b): 

• Big Boggy—administered by the FWS—is a 5,000-ac national wildlife refuge 

that borders Matagorda Bay and is approximately 9 mi southeast of the STP 

site. 

• San Bernard—administered by the FWS—is a 45,311-ac national wildlife 

refuge that contains coastal prairies and salt marshes in southern Matagorda 

and Brazoria Counties. 

The NRC is required under Section 102(2)(C) of NEPA to consult with and obtain the comments 

from any Federal agency that has jurisdiction by law or special expertise with respect to any 

environmental impact involved in the subject matter of the EIS. For example, during the course 
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of preparing the SEIS, the NRC consulted with the FWS and the NMFS. A complete list of key 

consultation correspondences is listed in Appendix D.

Regarding Coastal Zone Management Act (CZMA) compliance status, pursuant to 

Section 506.11(13) of Texas Administrative Code, STP license renewal falls within the definition 

of Federal agency action: 

A federal license or permit that a federal agency may issue that represents the 

proposed federal authorization, approval, or certification needed by the applicant 

to begin an activity. An action to renew, amend, or modify an existing license or 

permit shall not be considered an action subject to the CMP [Coastal 

Management Program] if the action only extends the time period of the existing

authorization without authorizing new or additional work or activities, would not 

increase pollutant loads to coastal waters or result in relocation of a wastewater 

outfall to a critical area, or is not otherwise directly relevant to the policies in 

§501.14 of this title (relating to Policies for Specific Activities and Coastal Natural 

Resource Areas).

In addition, in a letter dated January 29, 2010, the Coastal Coordination Council that 

administers the CZMA compliance in Texas explained: 

The project [STP] was undertaken before Texas had a federally approved [CMP]

and based on information provided in the [STPNOC’s] letter dated 

December 2, 2009, it has been determined that there are no significant 

unresolved consistency issues. Therefore, pursuant to Section 506.11(13), this 

project is consistent with the CMP goals and policies.

Hence, for license renewal purpose, STPNOC has obtained and maintained a consistency 

certification in accordance with the CZMA.

2.4 References 

10 CFR Part 20. Code of Federal Regulations, Title 10, Energy, Part 20, “Standards for 

protection against radiation.”

10 CFR Part 50. Code of Federal Regulations, Title 10, Energy, Part 50, “Domestic licensing of 

production and utilization facilities.”

10 CFR Part 51. Code of Federal Regulations, Title 10, Energy, Part 51, “Environmental 

protection regulations for domestic licensing and related regulatory functions.”

10 CFR Part 54. Code of Federal Regulations, Title 10, Energy, Part 54, “Requirements for 

renewal of operating licenses for nuclear power plants.”

10 CFR Part 61. Code of Federal Regulations, Title 10, Energy, Part 61, “Licensing 

requirements for land disposal of radioactive waste.”

10 CFR Part 71. Code of Federal Regulations, Title 10, Energy, Part 71, “Packaging and 

transportation of radioactive material.”

30 TAC 1-307. Texas Administrative Code, Title 30, Environmental Quality, Part 1, “Texas 

Commission on Environmental Quality,” Chapter 307, “Texas Surface Water Quality Standards.” 

31 TAC 10-356. Texas Administrative Code, Title 31, Natural Resources and Conservation, 

Part 10, “Texas Water Development Board,” Chapter 356, “Groundwater Management.” 

36 CFR Part 800. Code of Federal Regulations. Title 36, Parks, Forests, and Public Property, 

Part 800, “Protection of historic properties.” 
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40 CFR Part 81. Code of Federal Regulations, Title 40, Protection of Environment, Part 81, 

“Designation of areas for air quality planning purposes.”

40 CFR Part 141. Code of Federal Regulations, Title 40, Protection of Environment, Part 141, 

“National primary drinking water regulations.”

40 CFR Part 190. Code of Federal Regulations, Title 40, Protection of Environment, Part 190, 

“Environmental radiation protection standards for nuclear power operations.”

50 CFR Part 10. Code of Federal Regulations, Title 50, Wildlife and Fisheries, Part 10, 

“General provisions.”

50 CFR Part 22. Code of Federal Regulations, Title 50, Wildlife and Fisheries, Part 22, “Eagle 

permits.”

50 FR 50726. U.S. Fish and Wildlife Service. Endangered and threatened wildlife and plants; 

determination of endangered and threatened status for piping plover. Federal Register

50:50726–50734. December 11, 1985.

51 FR 6686. U.S. Fish and Wildlife Service. Endangered and threatened wildlife and plants; 

determination of the northern aplomado falcon to be an endangered species. Federal Register

51(37):6686–6690. February 26, 1986.

52 FR 21059. U.S. Fish and Wildlife Service. Endangered and threatened wildlife and plants; 

reclassification of the American alligator to threatened due to similarity of appearance 

throughout the remainder of its range. Federal Register 52(107):21059–21064. June 4, 1987. 

Available at <http://ecos.fws.gov/docs/federal_register/fr1263.pdf> (accessed April 15, 2013). 

66 FR 36038. U.S. Fish and Wildlife Service. Endangered and threatened wildlife and plants; 

final determination of critical habitat for wintering piping plovers. Federal Register

66(132):36038–36143. July 10, 2001.

69 FR 19975. National Oceanic and Atmospheric Administration. Endangered and threatened 

species; establishment of species of concern list, addition of species to species of concern list, 

description of factors for identifying species of concern, and revision of candidate species list 

under the Endangered Species Act. Federal Register 69(73):19975–19979. April 15, 2004. 

Available at <http://www.nmfs.noaa.gov/pr/pdfs/fr/fr69-19975.pdf> (accessed June 21, 2011).

74 FR 63337. U.S. Fish and Wildlife Service. Endangered and threatened wildlife and plants; 

90-Day finding on a petition to list Sprague’s Pipit as threatened or endangered. 

Federal Register 74(231):63337–63343. December 3, 2009. Available at

<http://www.gpo.gov/fdsys/pkg/FR-2009-12-03/pdf/E9-28868.pdf#page=1> (accessed 

April 11, 2013).

75 FR 25174. National Marine Fisheries Service. Endangered and threatened wildlife and 

plants; proposed listing for the largetooth sawfish. Federal Register 75(88):25174–25184. 

May 7, 2010.

75 FR 9282. U.S. Fish and Wildlife Service. General provisions—revised list of migratory birds. 

Federal Register 75(39):9282–9314. March 1, 2010.

76 FR 36491. U.S. Fish and Wildlife Service. Endangered and threatened wildlife and plants; 

eskimo curlew; initiation of 5-year status review and request for information. Federal Register

76(120):36491–36493. June 22, 2011. Available at 

<http://www.gpo.gov/fdsys/pkg/FR-2011-06-22/pdf/2011-15355.pdf> (accessed April 12, 2013).

77 FR 69994. U.S. Fish and Wildlife Service. Endangered and threatened wildlife and plants; 

review of native species that are candidates for listing as endangered or threatened; annual 
Affected Environment

2-80

notice of findings on resubmitted petitions; annual description of progress on listing activities. 

Federal Register 77(225):69994–70060. November 21, 2012.

78 FR 37282. U.S. Nuclear Regulatory Commission. Environmental Review for Renewal of 

Nuclear Power Plant Operating Licenses. Federal Register 78(119):37282–37324. 

June 20, 2013.

Aronson R, Bruckner A, Moore J, Precht B, Weil E. 2008. “Oculina varicosa.” Available at 

<http://www.iucnredlist.org/apps/redlist/details/133165/0> (accessed June 28, 2011).

[Audubon] Audubon Corkscrew Swamp Sanctuary. 2004. “American Alligator.” Available at 

<http://www.corkscrew.audubon.org/wildlife/alligators.html> (accessed June 21, 2011).

[Audubon] Audubon Society. 2011. “Christmas Bird Count Database for Matagorda 

County-Mad Island Marsh, 2009-2010.” Available at 

<http://audubon2.org/cbchist/count_table.html> (accessed September 16, 2011).

[Audubon] Audubon Society. 2013. Christmas Bird Count Database for Matagorda CountyMad Island Marsh (TXMM) unit, 1998–2012. Available at 

<http://netapp.audubon.org/CBCObservation/Historical/ResultsByCount.aspx> (accessed 

March 15, 2013).

Baker WB, Green GN. 1989. 1987-1988 Special Ecological Study for the South Texas Project. 

Houston, TX: Houston Light & Power Company. 46 p. ADAMS No. ML11256A057.

[BEG] Bureau of Economic Geology. 1996. “Physiographic Map of Texas.” The University of 

Texas at Austin. Available at 

<http://www.beg.utexas.edu/UTopia/images/pagesizemaps/physiography.pdf> (accessed 

September 20, 2011).

Campbell L. 2003. Endangered and Threatened Animals of Texas: Their Life History and 

Management. Austin, TX: Texas Parks and Wildlife Department. 127 p. Available at 

<http://www.tpwd.state.tx.us/publications/pwdpubs/media/pwd_bk_w7000_0013.pdf> (accessed 

September 7, 2011).

Clean Air Act of 1963, as amended. 42 U.S.C. §7401 et seq.

Clean Water Act of 1972, as amended. 33 U.S.C. §1251 et seq.

[CPGCD] Coastal Plains Groundwater Conservation District. 2011. Operating Permit, Permit 

No. OP-04122805. Bay City, TX. ADAMS No. ML11256A058.

Croker R. 1962. Growth and food of the gray snapper, Lutjanus griseus, in the Everglades 

National Park. Transactions of the American Fisheries Society 91(4):379–383.

DeVries D, Grimes CB, Lang KL, White DB. 1990. Age and growth of king and Spanish 

mackerel larvae and juveniles from the Gulf of Mexico and U.S. South Atlantic Bight. 

Environmental Biology of Fishes 29(1990):135–143.

[DOI] U.S. Department of Interior. 2013. Letter from S.R. Spencer, Regional Environmental 

Officer, DOI, to C. Bladey, NRC. Comments on the draft SEIS for the proposed South Texas 

license renewal. February 21, 2013. ADAMS No. ML13058A027. 

Drake KR, Thompson JE, Drake KL, Zonick C. 2001. Movements, habitat use, and survival of 

nonbreeding piping plovers. Condor 103:259–267. 

Ducks Unlimited. 2006. “Ducks Unlimited and Partners Conserve 35,000 Acres Along the 

Texas Gulf Coast.” Available at 
Affected Environment

2-81

<http://www.ducks.org/news-media/texas-prairie-wetlands-project> (accessed September 14, 

2011).

Ducks Unlimited and [HLPC] Houston Power and Lighting Company. 1996. Wetland 

Development Agreement for the Texas Prairie Wetland Project Gulf Coast Joint Venture. 

October 23, 1996. ADAMS No. ML11256A057.

Endangered Species Act of 1973, as amended. 16 U.S.C. §1531 et seq.

[ENSR] ENSR Corporation. 2008a. Aquatic Ecology—Main Cooling Reservoir and Circulating 

Water Intake Structure Study, Unit 3 and 4, Licensing Project. Prepared for STP Nuclear 

Operating Company. Houston, TX: ENSR. 53 p. ADAMS No. ML11256A057.

[ENSR] ENSR Corporation. 2008b. Ecological Survey Report—Threatened and Endangered 

Species. Prepared for STP Nuclear Operating Company. Houston, TX: ENSR. 32 p. ADAMS 

No. ML080660150.

[ENSR] ENSR Corporation. 2008c. Aquatic Ecology—Colorado River Monitoring Report, 

Units 3 and 4 Licensing Project. Houston, Texas. ADAMS No. ML081750196. 

[EOE] Encyclopedia of Earth. 2008. “Great Plains Ecoregion.” Updated October 16, 2008. 

Available at <http://www.eoearth.org/article/Great_Plains_ecoregion_(CEC)> (accessed 

September 13, 2011).

[EPA] U.S. Environmental Protection Agency. 1974. Information on Levels of Environmental 

Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of Safety. 

Washington, DC: EPA. Report 550/9-74-004. Available at 

<http://www.nonoise.org/library/levels74/levels74.htm.> (accessed May 9, 2011).

[EPA] U.S. Environmental Protection Agency. 2010a. “Office of Solid Waste.” Available at 

<http://www.epa.gov/osw> (accessed December 2010).

[EPA] U.S. Environmental Protection Agency. 2010b. “Safe Drinking Water Information System 

(SDWIS), County Search, Brazoria and Matagorda County, Texas.” Available at 

<http://iaspub.epa.gov/enviro/sdw_form_v2.create_page?state_abbr=TX.> (accessed 

June 2011).

[EPA] U.S. Environmental Protection Agency, 2010c, “Waste Environmental Management 

Systems,” Available at <http://www.epa.gov/osw/inforesources/ems/index.htm> (accessed 

December 2010).

[EPA] U.S. Environmental Protection Agency. 2011. “Green Book: Currently Designated 

Non-attainment Areas for All Criteria Pollutants.” August 30, 2011. Available at 

<http://epa.gov/oaqps001/greenbk/ancl.html> (accessed November 17, 2011).

[FMNH] Florida Museum of Natural History. 2009. “Ichthyology at the Florida Museum of 

Natural History, Education, Biological Profiles: King Mackerel.” Available at 

<http://www.flmnh.ufl.edu/fish/gallery/descript/kingmackerel/kingmackerel.html> (accessed 

September 9, 2011). ADAMS No. ML100600370.

[HL&P] Houston Light & Power Company. 1975. Final Environmental Report for Construction 

of STP, Units 1 & 2. 

[FWS] U.S. Fish and Wildlife Service. 2000. “Critical Habitat: What Is It?” May 2000. 

Available at 

<http://www.fws.gov/verobeach/images/pdflibrary/Critical%20Habitat%20Fact%20Sheet.pdf> 

(accessed June 21, 2011).
Affected Environment

2-82

[FWS] U.S. Fish and Wildlife Service. 2009. Piping Plover (Charadrius melodus) 5-Year 

Review: Summary and Evaluation. Hadley, MA and Lansing, MI: FWS. September 2009. 

214 p. Available at 

<http://www.fws.gov/midwest/endangered/recovery/5yr_rev/pdf/PipingPlover5yr2009.pdf> 

(accessed April 15, 2013). 

[FWS] U.S. Fish and Wildlife Service. 2011a. “Find Endangered Species: Species By County 

Report for Bexar, Brazoria, Colorado. DeWitt, Fayette, Gonzales, Guadalupe, Jackson, Lavaca, 

Matagorda, Wharton, and Wilson Counties.” Available at <http://www.fws.gov/endangered/> 

(accessed May 19, 2011).

[FWS] U.S. Fish and Wildlife Service. 2011b. Letter from AM Strand, Field Supervisor, to 

T Tran, Project Manager, NRC. Subject: Reply to request for species list for South Texas 

license renewal review. June 2, 2011. ADAMS No. ML11173A241.

[FWS] U.S. Fish and Wildlife Service. 2011c. “Big Boggy National Wildlife Refuge.” Available 

at <http://www.fws.gov/refuges/profiles/index.cfm?id=21542> (accessed September 27, 2011). 

[FWS] U.S. Fish and Wildlife Service. 2013a. “Find Endangered Species: Species By County 

Report for Matagorda County.” Available at <http://www.fws.gov/endangered/> (accessed 

March 8, 2013).

[FWS] U.S. Fish and Wildlife Service. 2013b. “Species Profile for Northern Aplomado Falcon 

(Falco femoralis septentrionalis).” Updated April 12, 2013. Available at 

<http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=B06V> (accessed 

April 12, 2013).

[FWS] U.S. Fish and Wildlife Service. 2013c. “Red Wolf Recovery Program: About the 

Recovery Program.” Updated February 13, 2013. Available at 

<http://www.fws.gov/redwolf/aboutrecovery.html> (accessed March 15, 2013).

[FWS] U.S. Fish and Wildlife Service. Undated. “Migratory Birds & Habitat Programs: 

Migratory Bird Treaty Act.” Available at <http://www.fws.gov/pacific/migratorybirds/mbta.htm> 

(accessed May 19, 2011).

[FWS-SWR] U.S. Fish and Wildlife Service, Southwest Regional Office. 2013. Species Lists by 

State and County for Brazoria, Matagorda, and Wharton Counties. Available at 

<http://www.fws.gov/southwest/es/ES_Lists_Main.cfm> (accessed March 8, 2013).

[GCBO] Gulf Coast Bird Observatory. 2011. “Clive Runnells Family Mad Island Marsh 

Preserve.” Available at <http://www.gcbo.org/html/madisland.pdf> (accessed September 27, 

2011).

[GMFMC] Gulf of Mexico Fishery Management Council. 2004. Final Environmental Impact 

Statement for the Generic Essential Fish Habitat Amendment to the Following Fishery 

Management Plans of the Gulf of Mexico (GOM): Shrimp, Red Drum, Reef Fish, Stone Crab, 

Coral and Coral Reef, Spiny Lobster, and Coastal Migratory Pelagic Resources. Tampa, FL: 

GMFMC. March 2004. 682 p. Available at 

<http://www.gulfcouncil.org/beta/gmfmcweb/downloads/Final%20EFH%20EIS.pdf> (accessed 

September 7, 2011).

Griffith G, Bryce S, Omernik J, Rogers A. 2007. Ecoregions of Texas. Project report to Texas 

Commission on Environmental Quality. Corvallis, OR: Dynamac Corporation. December 2007. 

134 p. Available at <ftp://ftp.epa.gov/wed/ecoregions/tx/TXeco_Jan08_v8_Cmprsd.pdf> 

(accessed September 12, 2011).
Affected Environment

2-83

Haig SM. 1992. “Piping Plover (Chardrius melodus).” In: Poole A, Stettenheim P, Gill F, 

(eds.). The Birds of North America, No. 2. Philadelphia, PA: The Academy of Natural 

Sciences; Washington, DC: The American Ornithologists Union. 18 pp.

Hector DPK. 1990. Northern Aplomado Falcon Recovery Plan. Prepared for the FWS 

Region 2, Albuquerque, NM. San Marcos, TX: Southwest State University. June 8, 1990. 65 p. 

Available at <http://ecos.fws.gov/docs/recovery_plan/900608.pdf> (accessed April 15, 2013).

Institute of Educational Science (IES). 2010. “College Opportunities Online Locator.” Zip 

Code 77414. October 2010. Available at <http://nces.ed.gov/ipeds/cool/RefineSearch.aspx> 

(accessed January 2011).

Jones SL. 2010. Sprague’s Pipit (Anthus spragueii) conservation plan. Washington, DC: U.S. 

Fish and Wildlife Service. 56 p. Available at <http://www.fws.gov/mountainprairie/species/birds/spraguespipit/SpraguesJS2010r4.pdf> (accessed March 15, 2013).

[MACTEC] MACTEC Engineering and Consulting, Inc. 2009. Conceptual Site Model for 

Units 1 and 2, Groundwater Protection Initiative, South Texas Project Electric Generating 

Station. Wadsworth, TX: MACTEC Engineering and Consulting, Inc. Revision 1. 

May 20, 2009. ADAMS No. ML11256A058.

[Matagorda County EDC] Matagorda County Economic Development Corporation. 2007. 

“Community Profile.” Available at <http://www.mcedc.net/index.php> (accessed April 2012).

Matthews JR, Moseley CJ (eds.). 1990. The Official World Wildlife Fund Guide to Endangered 

Species of North America. Volume 1. Plants, Mammals. Washington, DC: Beacham 

Publications, Inc.

McAden DC, Greene GN, Baker WB Jr. 1984. Colorado River Entrainment and Impingement 

Monitoring Program Phase Two Studies. Report #1. Prepared for STP Nuclear Operating 

Company. October 1984. 58 p. ADAMS No. ML11256A057.

McAden DC, Greene GN, Baker WB Jr. 1985. Colorado River Entrainment and Impingement 

Monitoring Program Phase Two Studies. Report #2. Prepared for STP Nuclear Operating 

Company. October 1984. 30 p. ADAMS No. ML11256A057.

Miller MP, Haig SM, Gratto-Trevor CL, Mullins TD. 2009. Molecular population genetic 

structure in the piping plover. U.S. Geological Survey Open File Report 2009–1032. 30 p. 

Available at <http://pubs.usgs.gov/of/2009/1032/pdf/OFR20091032.pdf> (accessed 

June 21, 2011).

Musick JA, Grubbs RD, Baum J, Cortés E. 2007. “Carcharhinus obscurus.” Available at 

<http://www.iucnredlist.org/apps/redlist/details/3852/0> (accessed June 28, 2011).

National Environmental Policy Act of 1969, as amended. 42 U.S.C. §4321 et seq.

National Historic Preservation Act of 1966. 16 U.S.C. §470 et seq.

NatureServe. 2013a. “Charadrius melodus.” NatureServe Explorer: An online encyclopedia of 

life [web application]. Version 7.1. Arlington, VA: NatureServe. Available at 

<http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Charadrius+melodus>. 

(accessed April 12, 2013). 

NatureServe. 2013b. “Falco femoralis septentrionalis.” NatureServe Explorer: An online 

encyclopedia of life [web application]. Version 7.1. Arlington, VA: NatureServe. Available at 

<http://www.natureserve.org/explorer/servlet/NatureServe?searchName=falco+femoralis+septe

ntrionalis >. (accessed April 12, 2013).
Affected Environment

2-84

NatureServe. 2013c. “Grus americana.” NatureServe Explorer: An online encyclopedia of life 

[web application]. Version 7.1. Arlington, VA: NatureServe. Available at 

<http://www.natureserve.org/explorer/servlet/NatureServe?searchName=grus+americana>. 

(accessed April 12, 2013).

NatureServe. 2013d. “Truncilla macrodon.” NatureServe Explorer: An online encyclopedia of 

life [web application]. Version 7.1. Arlington, VA: NatureServe. Available at 

<http://www.natureserve.org/explorer/servlet/NatureServe?searchName=truncilla+macrodon>. 

(accessed April 12, 2013).

[NCES] National Center for Education Statistics. 2010. “Search for Public School Districts.” 

Available at <http://www.nces.ed.gov/ccd/districtsearch/> (accessed June 2011).

[NMFS] National Marine Fisheries Service. 2009. “Species of Concern: Saltmarsh 

Topminnow.” January16, 2009. Available at 

<http://www.nmfs.noaa.gov/pr/pdfs/species/saltmarshtopminnow_detailed.pdf> (accessed 

September 7, 2011).

[NMFS] National Marine Fisheries Service. 2010a. “Bottlenose Dolphin (Tursiops truncatus 

truncates): Northern Gulf of Mexico Bay, Sound, and Estuarine Stocks.” November 2010. 

Available at <http://www.nmfs.noaa.gov/pr/pdfs/sars/ao2010dobn-gmxb.pdf> (accessed 

27 June 2011).

[NMFS] National Marine Fisheries Service. 2010b. Letter from M Croom, Assistant Regional 

Administrator for Habitat Conservation, to Johnson, Rulemaking and Directives Branch Chief, 

NRC. Subject: Concurrence with EFH Assessment for STP, Units 3 and 4. ADAMS 

No. ML101190379.

[NMFS] National Marine Fisheries Service. 2010c. Memorandum from RE Crabtree, Southeast 

Regional Administrator, to J Lecky, Office of Protected Resources Director. Subject: Removal 

of night shark from species of concern list. July 22, 2010. Available at 

<http://www.nmfs.noaa.gov/pr/pdfs/species/night_shark_dm.pdf> (accessed June 28, 2011).

[NMFS] National Marine Fisheries Service. 2010d. “Species of Concern: Ivory Tree Coral.” 

February 23, 2010. Available at 

<http://www.nmfs.noaa.gov/pr/pdfs/species/ivorytreecoral_detailed.pdf> (accessed 

June 28, 2011).

[NMFS] National Marine Fisheries Service. 2010e. “Species of Concern: Sand Tiger Shark.” 

February 23, 2010. Available at 

http://www.nmfs.noaa.gov/pr/pdfs/species/sandtigershark_detailed.pdf (accessed 

August 12, 2012).

[NMFS] National Marine Fisheries Service. 2011a. “Bottlenose Dolphin (Tursiops truncatus).” 

Available at <http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/bottlenosedolphin.htm> 

(accessed June 27, 2011).

[NMFS] National Marine Fisheries Service. 2011b. “Cetaceans: Whales, Dolphins, and 

Porpoises.” Available at <http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/> 

(accessed May 19, 2011).

[NMFS] National Marine Fisheries Service. 2011c. E-mail from T Mincey, Program Analyst, to 

T Tran, Project Manager, NRC. Subject: List of species under NMFS jurisdiction. 

March 3, 2011. ADAMS No. ML110690848.
Affected Environment

2-85

[NMFS] National Marine Fisheries Service. 2011d. “Proactive Conservation Program: Species 

of Concern.” January 20, 2011. Available at <http://www.nmfs.noaa.gov/pr/species/concern/> 

(accessed March 30, 2011).

[NMFS] National Marine Fisheries Service. 2011e. “Species of Concern List.” Available at 

<http://www.nmfs.noaa.gov/pr/species/concern/#list> (accessed June 28, 2011).

[NRC] U.S. Nuclear Regulatory Commission. 1975. Final Environmental Statement Related to 

the Proposed South Texas Project Units 1 & 2. Washington, DC: NRC. NUREG-75/019.

[NRC] U.S. Nuclear Regulatory Commission. 1986. Final Environmental Statement Related to 

the Operation of South Texas Project, Units 1 & 2. Washington, DC: NRC. NUREG-1171. 

August 1986. ADAMS No. ML11172A080.

[NRC] U.S. Nuclear Regulatory Commission. 1996. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. Washington, DC: NRC. NUREG-1437. May 1996. 

ADAMS Nos. ML040690705 and ML040690738.

[NRC] U.S. Nuclear Regulatory Commission. 1999. Section 6.3—Transportation, Table 9.1, 

Summary of findings on NEPA issues for license renewal of nuclear power plants. In: Generic 

Environmental Impact Statement for License Renewal of Nuclear Plants. Washington, DC: 

NRC. NUREG-1437, Volume 1, Addendum 1. August 1999. ADAMS No. ML04069720.

[NRC] U.S. Nuclear Regulatory Commission. 2000. Environmental Standard Review Plan: 

Standard Review Plans for Environmental Reviews for Nuclear Power Plants. Washington, DC: 

NRC. NUREG-1555.

[NRC] U.S. Nuclear Regulatory Commission. 2008. South Texas Project Units 3 and 4 COL

Site Audit and Scoping Trip Report. February 3-8, 2008. ADAMS No. ML081010440.

[NRC] U.S. Nuclear Regulatory Commission. 2011a. E-mail from B Martin, THC, to TK O’Neil, 

PNNL. Subject: STP license renewal—SHPO meeting. May 2, 2011. ADAMS 

No. ML11259A029. 

[NRC] U.S. Nuclear Regulatory Commission. 2011b. Environmental Impact Statement for 

Combined Licenses (COLs) for South Texas Project Electric Generating Station, Units 3 and 4. 

Washington, DC: NRC. NUREG-1937, Volumes 1 and 2. ADAMS Nos. ML11049A000 and 

ML11049A001.

[NRC] U.S. Nuclear Regulatory Commission. 2011c. Essential Fish Habitat Assessment for 

South Texas Project Electric Generating Station Units 3 and 4. Washington, DC: NRC. Final 

Report. ADAMS No. ML11049A001.

[NRC] U.S. Nuclear Regulatory Commission. 2011d. Letter from BM Pham, NRC, to DL Klima, 

Advisory Council on Historic Preservation. Subject: South Texas Project, Units 1 and 2, license 

renewal application review. January 27, 2011. ADAMS No. ML110200002.

[NRC] U.S. Nuclear Regulatory Commission. 2011e. Letter from BM Pham, NRC, to M Wolfe, 

Texas Historical Commission. Subject: South Texas Project, Units 1 and 2, license renewal 

application review (track no. 201002271). February 17, 2011. ADAMS No. ML110190549.

[NRC] U.S. Nuclear Regulatory Commission. 2011f. Letter from D Wrona, Branch Chief, to M 

Orms M, FWS. Subject: Request for concurrence on list of Federally protected species. 

February 16, 2011. ADAMS No. ML110190429.

[NRC] U.S. Nuclear Regulatory Commission. 2011g. Letter from T Tran, NRC, to GT Powell, 

STPNOC. Subject: Audit report regarding South Texas Project license renewal application—

cultural resources. July 18, 2011. ADAMS No. ML11173A304.
Affected Environment

2-86

[NRC] U.S. Nuclear Regulatory Commission. 2012a. Commission Voting Record for Final 

Rule: Revisions to Environmental Review For Renewal of Nuclear Power Plant Operating 

Licenses (10 CFR Part 51; RIN 3150-AI42). December 6, 2012. ADAMS No. ML12341A250.

[NRC] U.S. Nuclear Regulatory Commission. 2012b. Final Rule: Revisions to Environmental 

Review For Renewal of Nuclear Power Plant Operating Licenses (10 CFR Part 51; 

RIN 3150-AI42). SECY-12-0063. April 20, 2012. ADAMS No. ML110760045.

[NRC] U.S. Nuclear Regulatory Commission. 2013. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. Washington, DC: Office of Nuclear Reactor Regulation. 

NUREG-1437, Revision 1, Volumes 1, 2, and 3. June 2013. ADAMS Nos. ML13106A241, 

ML13106A242, and ML13106A244.

[NRCS] Natural Resources Conservation Service. 2011, “Web Soil Survey, Soil Map—

Matagorda County, Texas, Map Unit Description–Matagorda County, Texas.” April 12, 2011. 

Available at <http://websoilsurvey.nrcs.usda.gov/app> (accessed October 9, 2011).

Parker WT, Smith R, Foose T. 1990. Red Wolf Recovery/Species Survival Plan. Atlantia, GA: 

U.S. Fish and Wildlife Service Southeast Region. October 26, 1990. 115 p. Available at 

<http://ecos.fws.gov/docs/recovery_plan/901026.pdf> (accessed March 15, 2013).

Patillo ME, Czapla TE, Nelson DM, Monaco ME. 1997. Distribution and Abundance of Fishes 

and Invertebrates in Gulf of Mexico Estuaries. Volume 2, Species Life History Summaries. 

ELMR Reort No. 11. Silver Spring, MD: NOAA/NOS Strategic Environmental Assessments 

Division.

Pollard D, Smith A. 2005. “Carcharias taurus.” Available at 

<http://www.iucnredlist.org/apps/redlist/details/3854/0> (accessed June 28, 2011).

Ryder, PD. 1996. Ground Water Atlas of the United States, Oklahoma, Texas. Washington, 

DC: U.S. Geological Survey. Available at <http://pubs.usgs.gov/ha/ha730/ch_e/index.html> 

(accessed August 31, 2011).

Ryder, PD, Ardis, AF. 2002. Hydrology of the Texas Gulf Coast Aquifer Systems, Regional 

Aquifer-Systems Analysis-Gulf Coast Plain. Reston, VA: U.S. Geological Survey. U.S. 

Geological Survey Professional Paper 1416-E. 

Santana FM, Lessa R, Carlson J. 2006. “Carcharhinus signatus.” Available at 

<http://www.iucnredlist.org/apps/redlist/details/60219/0> (accessed June 28, 2011).

[STPNOC] South Texas Project Nuclear Operating Company. 2007. 2006 Annual 

Environmental Operating Report, South Texas Project Electric Generating Station. Bay City, 

TX: STPNOC. April 2007. ADAMS No. ML071270211. 

[STPNOC] South Texas Project Nuclear Operating Company. 2008. Letter from Gregory

Gibson, STPNOC, to NRC Document Control Desk. Subject: Response to RAI. July 15, 2008, 

No. ML082040684.

[STPNOC] South Texas Project Nuclear Operating Company. 2009a. Updated Final Safety 

Analysis Report Units 1 and 2. Bay City, TX: STPNOC. Revision 15. ADAMS No. 

ML103220222.

[STPNOC] South Texas Project Nuclear Operating Company. 2009b. Water Conservation 

Plan, STP Nuclear Operating Company, South Texas Project Electric Generating Station, 

Certificate of Adjudication 14-5437 A. May 1, 2009. Revision 2. ADAMS No. ML11256A058.
Affected Environment

2-87

[STPNOC] South Texas Project Nuclear Operating Company. 2010a. 2009 Annual 

Environmental Operating Report, South Texas Project Electric Generating Station. Bay City, 

TX: STPNOC. April 2010. ADAMS No. ML101260530.

[STPNOC] South Texas Project Nuclear Operating Company. 2010b. South Texas Project, 

Units 1 and 2, License Renewal Application. Bay City, TX: STPNOC. Appendix E, 

“Environmental Report.” September 2010. ADAMS No. ML103010263.

[STPNOC] South Texas Project Nuclear Operating Company. 2010c. South Texas Project, 

Units 3 and 4, Combined License Application. Bay City, TX: STPNOC. Part 2, “Final Safety 

Analysis Report,” Revision 4. ADAMS No. ML102860517.

[STPNOC] STP Nuclear Operating Company. 2010d. South Texas Project, Units 3 and 4, 

Combined License Application. Bay City, TX: STPNOC. Part 3, “Environmental Report,” 

Revision 4. ADAMS No. ML102860592. 

[STPNOC] South Texas Project Nuclear Operating Company (STPNOC). 2010e. Letter from 

Mark McBurnett, STPNOC, to NRC Document Control Desk. Subject: Additional Information 

Regarding Draft Environmental Impact Statement. September 9, 2010. ADAMS 

No. ML102600127.

[STPNOC] South Texas Project Nuclear Operating Company. 2011a. 2010 Annual 

Environmental Operating Report, South Texas Project Electric Generating Station. Bay City, 

TX: STPNOC. April 2011. ADAMS Nos. ML111250423 and ML111250429.

[STPNOC] South Texas Project Nuclear Operating Company. 2011b. Letter from AW Harrison, 

Manager Licensing, to NRC Document Control Desk. Subject: Transmittal of documents to 

support review of the STP LRA. TAC Nos. ME 4938 and ME 5122. STP Letter 

No. NOC-AE-11002720. August 31, 2011. ADAMS Nos. ML11256A056 and ML11256A059. 

[STPNOC] South Texas Project Nuclear Operating Company. 2011c. Letter from GT Powell, 

STPNOC, to NRC Document Control Desk. Subject: Response to RAI for the review of the 

STP LRA. July 5, 2011. ADAMS No. ML11193A016.

[STPNOC] South Texas Project Nuclear Operating Company. 2011d. Letter from GT Powell, 

Vice President, STPNOC, to NRC Document Control Desk. Subject: Response to RAI for the 

STP LRA. TAC Nos. ME4938 and ME5122. STP Letter No. NOC-AE-11002719. 

September 6, 2011. ADAMS No. ML11255A211.

[STPNOC] South Texas Project Nuclear Operating Company. 2011e. Letter from GT Powell, 

Vice President, STPNOC, NRC Document Control Desk. Subject: Response to RAI for the 

review of the STP LRA. TAC Nos. ME4938 and ME5122. STP Letter No. NOC-AE-11002723. 

September 12, 2011. ADAMS No. ML11259A014.

[STPNOC] South Texas Project Nuclear Operating Company. 2011f. Letter from GT Powell, 

STPNOC, to NRC Document Control Desk. Subject: Response to RAI for the review of the 

STP LRA. October 18, 2011. ADAMS No. ML11298A085. 

[STPNOC] South Texas Project Nuclear Operating Company. 2011g. Letter from GT Powell, 

Vice President, STPNOC, NRC Document Control Desk. Subject: response to RAI for the 

review of the LRA. July 5, 2011. ADAMS No. ML11193A074.

[STPNOC] South Texas Project Nuclear Operating Company. 2012a. South Texas Project, 

Units 1 and 2, Clarification of Information. Bay City, TX: STPNOC. January 10, 2012. ADAMS 

No. ML12011A188.
Affected Environment

2-88

[STPNOC] South Texas Project Nuclear Operating Company. 2012b. Letter from GT Powell, 

Vice President, STPNOC, NRC Document Control Desk. Subject: response to RAI for the 

review of the LRA. March 12, 2012. ADAMS No. ML12079A014. 

[STPNOC] South Texas Project Nuclear Operating Company. 2012c. Letter from SL 

Dannhardt, Manager, Environmental, STPNOC, NRC Document Control Desk. Subject: 

Renewal of the wastewater discharge permit. April 17, 2012. ADAMS No. ML12114A198.

[STPNOC] South Texas Project Nuclear Operating Company. 2012d. 2011 Annual 

Environmental Operating Report, South Texas Project Electric Generating Stations. Bay City, 

TX: STPNOC. April 2012. ADAMS Nos. ML12130A266 and ML12130A267.

[STPNOC] South Texas Project Nuclear Operating Company. 2013a. Letter from DW 

Rencurrel, Senior Vice President, STPNOC, NRC Document Control Desk. Subject: Update to 

license renewal application–environmental permits. January 21, 2013. ADAMS 

No. ML13032A074.

[STPNOC] South Texas Project Nuclear Operating Company. 2013b. 2012 Annual 

Environmental Operating Report, South Texas Project Electric Generating Stations. Bay City, 

TX: STPNOC. April 2013. ADAMS Nos. ML13148A039 and ML13148A040.

[TCEQ] Texas Commission on Environmental Quality. 2005. STPNOC TPDES Permit 

No. WQOOO 1908000, Permit to Discharge Wastes. July 21, 2005. ADAMS 

No. ML11256A057.

[TCEQ] Texas Commission on Environmental Quality. 2009. Letter from L Lancaster, Team 

Leader Application Review and Processing Team, TCEQ, to SL Dannhardt, STPNOC. Subject: 

Declaration of Administrative Completeness, STPNOC, Permit No. WQ0001908000 (EPA ID 

No. TX0064947) (RN102395654), Type of Authorization: Renewal. July 13, 2009. ADAMS 

No. ML11255A211.

[TCEQ] Texas Commission on Environmental Quality. 2011. “Draft 2010 Texas Integrated 

Report for Clean Water Act Sections 305(b) and 303(d).” March 8, 2011. Available at 

<http://www.tceq.texas.gov/waterquality/ assessment/10twqi/10twqi> (accessed 

October 20, 2011).

Texas Historical Commission. 2011. “Celebrate Native American Heritage in November.” 

Available at <http://www/thc/.state.tx.us/news/whatsnewstories/wnnamnth.shtml> (accessed 

October 28, 2011). 

Texas Water Code, Title 2, Water Administration, Chapter 36, Groundwater Conservation 

Districts. Available at <http://www.twdb.state.tx.us/gwrd/gcd/gcdhome.htm> (accessed 

July 2012).

[TMMSN] Texas Marine Mammal Stranding Network. 2011. “The Gulf of Mexico’s Marine 

Mammals.” January 2, 2011. Available at 

<http://www.sci.tamucc.edu/tmmsn/29Species/marine.html> (accessed May 19, 2011).

[TPWD] Texas Parks and Wildlife Department. 2011a. “Brazos Bend State Park.” Available at 

<http://www.tpwd.state.tx.us/spdest/findadest/parks/brazos_bend/> (accessed 

September 27, 2011).

[TPWD] Texas Parks and Wildlife Division. 2011b. “Jaguarundi.” Available at 

<http://www.tpwd.state.tx.us/publications/pwdpubs/media/pwd_bk_w7000_0013_jaguarundi.

pdf> (accessed September 7, 2011).
Affected Environment

2-89

[TPWD] Texas Parks and Wildlife Division. 2011c. Letter from A Turner, Wildlife Habitat 

Assessment Program, to B Pham, Branch Chief, NRC. Subject: Reply to request for species 

list for South Texas license renewal. April 20, 2011. ADAMS No. ML11119A009.

[TPWD] Texas Parks and Wildlife Department. 2011d. “Mad Island.” Available at 

<http://www.tpwd.state.tx.us/huntwild/hunt/wma/find_a_wma/list/?id=39> (accessed 

September 27, 2011).

[TPWD] Texas Parks and Wildlife Division. 2011e. “Ocelot (Leopardus pardalis).” Available at 

<http://www.tpwd.state.tx.us/huntwild/wild/species/ocelot/> (accessed 12 April 2013). 

[TPWD] Texas Parks and Wildlife Division. 2011f. “Rare, Threatened, and Endangered 

Species of Texas for Bexar, Brazoria, Colorado, DeWitt, Fayette, Gonzales, Guadalupe, 

Jackson, Lavaca, Matagorda, Wharton, and Wilson Counties.” Available at 

<http://gis.tpwd.state.tx.us/TpwEndangeredSpecies/DesktopDefault.aspx> (accessed 

May 19, 2011).

[TPWD] Texas Parks and Wildlife Division. 2013a. “Rare, Threatened, and Endangered Species 

of Texas for Brazoria, Matagorda, and Wharton Counties.” Available at 

<http://www.tpwd.state.tx.us/gis/ris/es/> (accessed March 8, 2013).

[TPWD] Texas Parks and Wildlife Division. 2013b. “Whooping Crane (Grus americana).” 

Available at <http://www.tpwd.state.tx.us/huntwild/wild/species/whooper/> (accessed 12 April 

2013).

[TSHA] Texas State Historical Association. 2011. “Texas Almanac: Population History of 

Counties from 1850–2010.” Available at <http://www.texasalmanac.com/topics/population> 

(accessed January 2011).

[TSWGW] Texas Saltwater and Fishing Guides Web. 2005. “King Mackerel (Kingfish).” 

Available at <http://www.txsaltwaterfishingguides.com/FishFacts/kingfish.htm> (accessed 

September 9, 2011). ADAMS No. ML100600370. 

[TWDB] Texas Water Development Board. 2006. Aquifers of the Gulf Coast of Texas. Austin, 

TX: TWDB. Report 365. February 2006. Available at 

<http://www.twdb.state.tx.us/publications/reports/GroundWaterReports/GWReports/R365/

AGCindex.htm> (accessed August 31, 2011).

[TWDB] Texas Water Development Board. 2007. State Water Plan—Water for Texas 2007. 

Austin, TX: TWDB Document No. GP-8-1. Volume 1. January 2007. Available at 

<http://www.twdb.state.tx.us/wrpi/swp/swp.asp> (accessed August 31, 2011).

[TXDOT] Texas Department of Transportation. 2011. “District Traffic Maps—2010.” Available 

at <http://ftp.dot.state.tx.us/pub/txdot-info/tpp/traffic_counts/2010/ykm_base.pdf> (accessed 

April 2011). 

University of Texas at Austin. 2011. “Texas Beyond History.” Available at 

<http://www/texasbeyondhistory.net/faq/index.html#9> (accessed October 28, 2011). 

[USACE] U.S. Army Corps of Engineers. 2009. Letter from K Jaynes, Compliance 

Section Chief, Galveston District, to R Kiesling, STPNOC. Subject: Jurisdictional wetlands on 

the South Texas site. May 14, 2009. ADAMS No. ML11256A057.

[USCB] U.S. Census Bureau. 2010. “American FactFinder, Census 2000 and 2006–2008, 

3-Year Estimate, American Community Survey, State and County QuickFacts on Brazoria and 

Matagorada Counties. Housing Characteristics for 2000 and 2006-2008, 3-Year Estimate. 

Profile of Selected Economic Characteristics: 2000 and 2010.” Available at 

<http://factfinder.census.gov and http://quickfacts.census.gov> (accessed January 2011). 
Affected Environment

2-90

[USDA NASS] U.S. Department of Agriculture National Agricultural Statistics Service. 2009. 

“2007 Census of Agriculture, Volume 1, Chapter 2, Table 1 and Table 7.” December 2009. 

Available at 

<http://www.agcensus.usda.gov/Publications/2007/Full_Report/Volume_1,_Chapter_2_County_

Level/Texas/index.asp> (accessed June 2011).

[USGS] U.S. Geological Survey. 2008. “Geologic Hazards Team Interactive Map Server, 

National Seismic Hazard Maps—2008.” April 23, 2008. Available at <http://gldims.cr.usgs.gov> 

(accessed September 20, 2011).

[USGS] U.S. Geological Survey. 2011a. “Circular Area Earthquake Search, NEIC: Earthquake 

Search Results, U.S. Geological Survey Earthquake Database.” (search parameters: 

Significant U.S. Earthquakes (1569–1989) Database, Latitude 28.7951 N, Longitude -96.04900 

W, Radius 550 km). October 4, 2010. Available at 

<http://earthquake.usgs.gov/earthquakes/eqarchives/epic/epic_circ.php> (accessed 

September 20, 2011).

[USGS] U.S. Geological Survey. 2011b. “Circular Area Earthquake Search, NEIC: Earthquake 

Search Results, U.S. Geological Survey Earthquake Database.” (search parameters: 

USGS/NEIC (PDE) 1973 Database, Latitude 28.7951 N, Longitude -96.04900 W, Radius 

200 km). October 4, 2010. Available at 

<http://earthquake.usgs.gov/earthquakes/eqarchives/epic/epic_circ.php> (accessed 

September 20, 2011).

[USGS] U.S. Geological Survey. 2011c. “Texas Earthquake Information, Seismicity Map of 

Texas, Seismic Hazard Map of Texas.” Available at 

<http://earthquake.usgs.gov/earthquakes/states/index.php?regionID=43> (accessed 

September 20, 2011).

[USGS] U.S. Geological Survey. 2011d. “USGS Surface-Water Annual Statistics for the 

Nation, USGS 08162500, Colorado River Near Bay City, TX.” Available at 

<http://waterdata.usgs.gov/nwis/annual/?referred_module=sw&site_no=08162500&por_

08162500_1=1460,00060,1,1948,2011&year_type=W&format=html_table&date_format=YYYYMM-DD&rdb_compression=file&submitted_form=parameter_selection_list> (accessed 

August 31, 2011).

Wai CN, Huntsman G. 2006a. “Epinephelus drummondhayi.” Available at 

<http://www.iucnredlist.org/apps/redlist/details/7854/0> (accessed June 28, 2011).

Wai CN, Huntsman G. 2006b. “Hyporthodus nigritus.” Available at 

<http://www.iucnredlist.org/apps/redlist/details/7860/0> (accessed June 28, 2011).

[WEG] Wild Earth Guardians. Petition to list the saltmarsh topminnow (Fundulus jenkinsi) under 

the U.S. Endangered Species Act. September 3, 2010. Available at 

<http://sero.nmfs.noaa.gov/pr/esa/Candiate%20Spp/Saltmarsh%20Topminnow%20Petition-1.

pdf> (accessed June 28, 2011).

Wiken E, Nava FJ, Griffith G. 2011. North American Terrestrial Ecoregions—Level III. 

Montreal, Canada: Commission for Environmental Cooperation. 149 p. Available at 

<ftp://ftp.epa.gov/wed/ecoregions/pubs/NA_TerrestrialEcoregionsLevel3_Final-2june11_CEC.

pdf> (accessed September 12, 2011).

Wilber, D. 1989. Reproductive biology and distribution of stone crabs (Xanthidae, menippe) in 

the hybrid zone on the northeastern Gulf of Mexico. Marine Ecology Progress 

Series 52(1989):235-244.
Affected Environment

2-91

Young, SC, Kelly, V, Budge, T, Deeds, N. 2007. FINAL Development of the LSWP 

Groundwater Flow Model for the Chicot and Evangeline Aquifers in Colorado, Wharton, and 

Matagorda Counties. Austin, TX: URS Corporation, INTERA, and Baer Engineering and 

Consulting. Available at 

<http://www.lcra.org/library/media/public/docs/lswp/findings/URS_Mitigation_report_final.pdf>. 

ADAMS No. ML100471604.

3-1 

3.0 ENVIRONMENTAL IMPACTS OF REFURBISHMENT

Facility owners or operators may need to undertake or, for economic or safety reasons, may 

choose to perform refurbishment activities in anticipation of license renewal or during the license 

renewal term. The major refurbishment class of activities characterized in the Generic 

Environmental Impact Statement for License Renewal of Nuclear Plants (GEIS) (NRC 1996) is 

intended to encompass actions that typically take place only once in the life of a nuclear plant, if 

at all. Examples of these activities include, but are not limited to, replacement of boiling-water 

reactor recirculation piping and pressurized-water reactor steam generators. These actions 

may have an impact on the environment beyond those activities occurring during normal 

operations for which the activities require evaluation, depending on the type of action and the 

plant-specific design. Table 3–1 lists the environmental issues associated with refurbishment 

that the U.S. Nuclear Regulatory Commission (NRC) staff (the staff) determined to be 

Category 1 issues in the GEIS.

Table 3–1. Category 1 Issues Related to Refurbishment

Issue GEIS Section(s)

Surface water quality, hydrology, and use (for all plants)

Impacts of refurbishment on surface water quality 3.4.1

Impacts of refurbishment on surface water use 3.4.1

Aquatic ecology (for all plants)

Refurbishment 3.5

Groundwater use and quality

Impacts of refurbishment on groundwater use and quality 3.4.2

Land use

Onsite land use 3.2

Human health

Radiation exposures to the public during refurbishment 3.8.1

Occupational radiation exposures during refurbishment 3.8.2

Socioeconomics 

Public services: public safety, social services, and tourism and

recreation 3.7.4; 3.7.4.3; 3.7.4.4; 3.7.4.6

Aesthetic impacts (refurbishment) 3.7.8

Table source: Table B–1 in Appendix B, Subpart A, to 10 CFR Part 51

Table 3–2 lists environmental issues related to refurbishment that the NRC staff determined to 

be plant-specific or inconclusive in the GEIS. These issues are Category 2 issues. The 

definitions of Category 1 and 2 issues can be found in Section 1.4 of this supplemental 

environmental impact statement (SEIS). 
Environmental Impacts of Refurbishment

3-2 

Table 3–2. Category 2 Issues Related to Refurbishment

Issue GEIS Section(s) 10 CFR 51.53(c)(3)(ii) 

Subparagraph 

Terrestrial resources

Refurbishment impacts 3.6 E

Threatened or endangered species (for all plants)

Threatened or endangered species 3.9 E

Air quality

Air quality during refurbishment

(non-attainment and maintenance areas) 3.3 F 

Socioeconomics 

Housing impacts 3.7.2 I

Public services: public utilities 3.7.4.5 I

Public services: education (refurbishment) 3.7.4.1 I

Offsite land use (refurbishment) 3.7.5 I

Public services, transportation 3.7.4.2 J

Historic and archaeological resources 3.7.7 K

Environmental justice

Environmental justice(a) Not addressed Not addressed

(a) Guidance related to environmental justice was not in place at the time the NRC prepared the GEIS and the 

associated revision to 10 CFR Part 51. If an applicant plans to undertake refurbishment activities for license 

renewal, the applicant’s Environmental Report (ER) and the staff’s SEIS must address environmental justice.

Table source: Table B–1 in Appendix B, Subpart A, to 10 CFR Part 51

Table B.2 of the GEIS identifies systems, structures, and components (SSCs) that are subject to 

aging and might require refurbishment to support continued operation during the license 

renewal period of a nuclear facility. In preparation for its license renewal application, South 

Texas Project Nuclear Operating Company (STPNOC) performed an evaluation of these SSCs 

pursuant to Section 54.21 of Title 10, Energy, of the Code of Federal Regulations

(10 CFR 54.21) to identify the need to undertake any major refurbishment activities that would 

be necessary to support the continued operation of South Texas Project (STP) during the 

proposed 20-year period of extended operation.

In the ER, STPNOC indicated that, in accordance with 10 CFR Part 54, STPNOC has submitted 

an integrated plant assessment (IPA) addressing the aging management of SSC for license 

renewal. The IPA does not identify the need to undertake any major refurbishment activities 

that are necessary to support continued operation of STP during the period of extended 

operation (STPNOC 2010). Furthermore, STPNOC indicated that it has replaced the steam 

generator and reactor heads to meet the operational needs under the current license. 

Therefore, the staff does not assess refurbishment activities in this SEIS.
Environmental Impacts of Refurbishment

3-3 

3.1 References

10 CFR Part 51. Code of Federal Regulations, Title 10, Energy, Part 51, “Environmental

protection regulations for domestic licensing and related regulatory functions.”

10 CFR Part 54. Code of Federal Regulations, Title 10, Energy, Part 54, “Requirements for 

renewal of operating licenses for nuclear power plants.”

[NRC] U.S. Nuclear Regulatory Commission. 1975. Final Environmental Statement Related to 

The Proposed South Texas Project, Units 1 and 2. Washington, DC: NRC. NUREG-75/019. 

March 1975. ADAMS No. ML11174A118

[NRC] U.S. Nuclear Regulatory Commission. 1996. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. Washington, DC: NRC. NUREG-1437. May 1996. 

ADAMS Nos. ML040690705 and ML040690738.

[NRC] U.S. Nuclear Regulatory Commission. 1999. Section 6.3, Transportation, Table 9.1, 

Summary of findings on NEPA issues for license renewal of nuclear power plants. In: Generic 

Environmental Impact Statement for License Renewal of Nuclear Plants. Washington, DC: 

NRC. NUREG-1437, Volume 1, Addendum 1. August 1999. ADAMS No. ML04069720.

[STPNOC] South Texas Plant Nuclear Operating Company. 2010b. “South Texas Project, 

Applicant’s Environmental Report—Operating License Renewal Stage, South Texas Project

Units 1 & 2.” September 2010. ADAMS No. ML103010263. 

4-1 

4.0 ENVIRONMENTAL IMPACTS OF OPERATION

This chapter addresses potential environmental impacts related to the period of extended 

operation of South Texas Project (STP). These impacts are grouped and presented according 

to resource. Generic issues (Category 1) rely on the analysis presented in the Generic 

Environmental Impact Statement (GEIS) for License Renewal of Nuclear Plants

(NRC 1996, 1999, 2013d), unless otherwise noted. Site-specific issues (Category 2) have been 

analyzed for STP. However, some issues are not applicable to STP because of site 

characteristics or plant features. Section 1.4 of this supplemental environmental impact 

statement (SEIS) provides an explanation of the criteria for Category 1 and Category 2 issues, 

as well as the definitions of SMALL, MODERATE, and LARGE. In addition, as described in 

Section 1.4, the U.S. Nuclear Regulatory Commission (NRC) has published a final rule 

(78 FR 37282, June 20, 2013) revising its environmental protection regulation, Title 10 of the 

Code of Federal Regulations (10 CFR) Part 51, “Environmental protection regulations for 

domestic licensing and related regulatory functions.” The final rule consolidates similar 

Category 1 and 2 issues, changes some Category 2 issues into Category 1 issues, and 

consolidates some of those issues with existing Category 1 issues. The revised rule also adds 

new Category 1 and 2 issues. These issues are discussed in Section 4.11.

4.1 Land Use

Onsite land use issues that could be affected by license renewal are listed in Table 4–1. As 

discussed in the GEIS, onsite land use and powerline right-of-way (ROW) conditions are 

expected to remain unchanged during the license renewal term at all nuclear plants; thus, 

impacts would be SMALL. These issues, therefore, were classified as Category 1 issues. 

Section 2.2.1 of this SEIS describes the land use conditions at STP.

The NRC staff reviewed and evaluated South Texas Project Nuclear Operating Company’s 

(STPNOC’s) Environmental Report (ER) (STPNOC 2010b), scoping comments, and other 

available data on STP, Units 1 and 2, were reviewed and evaluated for new and significant 

information. The review included an audit conducted by the NRC staff at the STP site. No new 

and significant information was identified during this review that would change the conclusions 

presented in the GEIS. Therefore, for these Category 1 issues, impacts during the renewal term 

are not expected to exceed those discussed in the GEIS.

Table 4–1. Land Use Issues

4.2 Air Quality

Section 2.2.2 of this SEIS describes the meteorology and air quality in the vicinity of the STP 

site.

Issue GEIS Section Category

Onsite land use 4.5.3 1

Powerline ROW 4.5.3 1

Source: Table B–1 in Appendix B, Subpart A, to 10 CFR Part 51
Environmental Impacts of Operation

4-2 

The air quality issue applicable to STP during the renewal term is discussed below and listed in 

Table 4–2. The GEIS did not identify any Category 2 issues related to air quality. The NRC 

staff did not identify any new and significant information during the review of the applicant’s ER 

(STPNOC 2010b), the staff’s site audit, the scoping process, or the evaluation of other available 

information. Therefore, there are no impacts related to these issues beyond those discussed in 

the GEIS. For these issues, the GEIS concluded that the impacts are SMALL, and additional 

site-specific mitigation measures are unlikely to be sufficiently beneficial to warrant 

implementation.

Table 4–2. Air Quality Issues

4.3 Surface Water Resources

The surface water use, hydrology, and surface water quality issues potentially applicable to 

STP, Units 1 and 2, are discussed in the following sections and listed in Table 4–3. Surface 

water-related aspects and conditions relevant to STP, Units 1 and 2, are described in 

Sections 2.1.7.1 and 2.2.4 of this SEIS. 

Table 4–3. Surface Water Resources Issues

4.3.1 Generic Surface Water Issues

NRC did not identify any new and significant information with regard to Category 1 (generic) 

surface water issues based on review of the ER (STPNOC 2010b), the public scoping process, 

or as a result of the environmental site audit. The NRC staff also reviewed other sources of 

information such as various permits and data reports. As a result, no information or impacts 

related to these issues were identified that would change the conclusions presented in the 

GEIS. Therefore, it is expected that there would be no impacts related to these Category 1 

issues during the renewal term beyond those discussed in the GEIS. For these surface water 

issues, the GElS concludes that the impacts are SMALL.

Issue GEIS Section Category

Air quality effects of transmission lines 4.5.2 1

Source: Table B–1 in Appendix B, Subpart A, to 10 CFR Part 51

Issues GEIS Section Category

Altered current patterns at intake & discharge structures 4.2.1.2.1 1

Altered salinity gradients 4.2.1.2.2 1

Discharge of chlorine or other biocides 4.2.1.2.4 1

Discharge of sanitary wastes & minor chemical spills 4.2.1.2.4 1

Discharge of other metals in wastewater 4.2.1.2.4 1

Water use conflicts (plants with cooling towers & cooling ponds using 

makeup water from a small river with low flow) 4.3.2.1 2 

Source: STPNOC 2010b, 2011b and Table B–1 in Appendix B, Subpart A, to 10 CFR Part 51
Environmental Impacts of Operation

4-3 

4.3.2 Surface Water Use Conflicts—Plants Using Makeup Water from a Small River with 

Low Flow 

For nuclear power plants using cooling towers or cooling ponds that are supplied with makeup 

water from a small river, the potential impact on the flow of the river and related impacts on 

instream and riparian ecological communities is considered a Category 2 issue; thus, it requires 

a plant-specific assessment. The requirement for this assessment is specified by 

10 CFR 51.53(c)(3)(ii)(A), which also defines a small river as one whose annual flow rate is less 

than 3.15x1012 ft3

/yr (9x1010 m3/yr) or 100,000 cfs (2,820 m3/s). In evaluating the potential 

impacts resulting from surface water use conflicts associated with license renewal, the NRC 

staff uses as its baseline the existing surface water resource conditions described in 

Sections 2.1.7.1 and 2.2.4.1 of this SEIS. These baseline conditions encompass the existing 

hydrologic (flow) regime of the surface water(s) potentially affected by continued operations as 

well as the magnitude of surface water withdrawals for cooling and other purposes (as 

compared to relevant appropriation and permitting standards). The baseline also considers 

other downstream uses and users of surface water. 

STP, Units 1 and 2, has a closed-cycle heat-dissipation system that uses a cooling pond, the 

main cooling reservoir (MCR), with makeup water supplied from a small river, the lower 

Colorado River, with a mean annual discharge equivalent to 82.6x109 ft3

/yr (23.4x108 m3/yr) or 

2,620 cfs (74.1 m3

/s). Therefore, an assessment of the impact of the proposed action on the 

flow of the river is required.

In the State of Texas, water use is regulated by the Texas Water Code. Surface water belongs 

to the State (Water Code, Title 2, Subtitle B, Chapter 11, Section 11.021). The right to use 

surface waters of the State can be acquired in accordance with the provisions of the Texas 

Water Code, Chapter 11. Because the Colorado River Basin is currently heavily appropriated 

(used or obligated for use), future water users in this basin would likely obtain surface water by 

purchasing or leasing existing appropriations. The Texas Water Development Board (TWDB) 

uses 16 planning regions, the Regional Water Planning Areas (or regions), to plan and finance 

water supply projects. The regions prepare plans within their areas that are compiled into the 

State Water Plan. The most recent plan was adopted by the TWDB in November 2006 

(TWDB 2007). For this SEIS, the staff reviewed the best available information for its analysis. 

Currently, the State of Texas is in the 2011 to 2016 planning cycle. The regions have compiled 

the 2011 Regional Water Plans. The 2012 State Water Plan has been released for public 

comment (TWDB 2011). The STP site is located in the Lower Colorado Regional Water 

Planning Group (LCRWPG), or Region K. 

STPNOC owns water rights from the lower Colorado River to operate power reactors on the 

STP site. The waters of the Colorado River for STPNOC’s use are adjudicated (administered or 

allotted) via a water right secured in 1989 (STPNOC 2010b). An agreement between the Lower 

Colorado River Authority (LCRA) and STPNOC specifies the conditions related to STPNOC’s 

withdrawal (diversion) of water from the Colorado River. STPNOC is allowed to withdraw 

102,000 ac-ft/yr (126 million m3

/yr) from the Colorado River at a maximum withdrawal rate of 

1,200 cfs (34.4 m3

/s) or 540,000 gpm. However, STPNOC is limited to withdrawing 55 percent 

of the river flow that exceeds 300 cfs (8.5 m3

/s) or 135,000 gpm (STPNOC 2009a; 

TCEQ 2009a). In other words, STPNOC is limited in its ability to withdraw water from the 

Colorado River during low flow conditions (i.e., 55 percent of the river flow at the volumetric flow 

rate that exceeds 300 cfs).

STPNOC’s historical withdrawals of surface water from the Colorado River for plant operations 

are summarized in Table 4–4. 
Environmental Impacts of Operation

4-4 

Table 4–4. Surface Water Withdrawals and Usage for Calendar Years 2003–2010 

for STP, Units 1 and 2

Calendar Year Water Withdrawal (ac-ft) (a) Water Use (ac-ft)

2003 0 27,800

2004 62,374 37,963

2005 5,694 35,383

2006 50,012 37,912

2007 58,740 39,403

2008 10,303 38,186

2009 72,464 38,008

2010 43,213 37,893

(a) To convert ac-ft to m3

, multiply by 1,233.5. To convert ac-ft to gal., multiply by 325,851. 

Source: STPNOC 2010b, 2011b

Between 2003 and 2010, STPNOC withdrew an average of 37,850 ac-ft/yr (46.7 million m3/yr) 

from the Colorado River and consumed an average of 36,569 ac-ft/yr (45.1 million m3

/yr) to 

support the operations of STP, Units 1 and 2. For a given year, withdrawals from the lower 

Colorado River can be significantly less or more than corresponding water use because of rules 

for water withdrawal specified in the LCRA–STPNOC contract (right to purchase or use), which 

are based on river flow and meteorological conditions that affect evaporation from the MCR. In 

2003, STPNOC withdrew no water from the Colorado River but consumptively used 27,800 ac-ft 

(34.3 million m3

). The following year, STPNOC had to withdraw 62,374 ac-ft (76.9 million m3) of 

river water to cover the 37,963 ac-ft (46.8 million m3

) of consumption and to replenish the MCR 

storage (the MCR functions and specifications are described in Section 2.1.6). The average, 

minimum, and maximum yearly withdrawals from the lower Colorado River over the 

2003 to 2010 period are 36, 0, and 71 percent of the STPNOC annual water rights of 

102,000 ac-ft (126 million m3

). 

The LCRWPG adopted its 2011 Region Plan in July 2010 (LCRWPG 2010). The LCRWPG 

estimated that the total water demand in Region K would increase from 1,086,692 ac-ft/yr 

(1.34 billion m3

/yr) in 2010 to 1,382,534 ac-ft/yr (1.71 billion m3/yr) in 2060, mainly due to a 

projected doubling of the population of Region K over the timeframe. The LCRWPG estimated 

that the water available to Region K would decline from 1,331,715 ac-ft/yr (1.64 billion m3

/yr) in 

2010 to 1,289,453 ac-ft/yr (1.59 billion m3

/yr) in 2060. The LCRWPG estimated that region-wide 

water shortages would be 297,000 and 367,000 ac-ft/yr (366 and 453 million m3

/yr) in 2030 and 

2060, respectively (LCRWPG 2010). To estimate shortages, the LCRWPG used the following 

conservative assumptions:

• Available water would be that during a historical drought of record. 

• All water rights would be used fully and simultaneously.

• Interruptible water from LCRA and municipal return flows to the Colorado 

River would not be available. 
Environmental Impacts of Operation

4-5 

These assumptions are conservative because they minimize water availability and maximize 

water use, thereby maximizing potential shortages.

The region plans to address shortages by using a variety of strategies. These water 

management strategies include use of municipal return flows, conservation, reuse, new water 

storage facilities, aquifer storage of surface water, new groundwater supply development, 

saltwater desalination, and intra-region transfer of water from areas with surplus. The LCRWPG 

estimated that the implementation of all water management strategies could yield an additional 

349,862 to 610,750 ac-ft/yr (432 to 754 million m3

/yr) to meet the estimated shortages 

(LCRWPG 2010).

During the past 5 years, withdrawals from the lower Colorado River to support the operations of 

STP, Units 1 and 2, have averaged 46,946 ac-ft/yr (57.9 million m3

/yr), which is equivalent to 

2.5 percent of the mean annual discharge of 2,620 cfs (74.1 m3

/s) or approximately 

1.89 million ac-ft/yr (2.3 billion m3

/yr) for the river. The average withdrawal for STP, Units 1 

and 2, is 3.5 and 3.6 percent of the water available to Region K in 2010 and 2060, respectively. 

The 2060 projection is based on the assumption that no implementation of any strategies to 

augment (or to change) regional water supply would have taken place. STPNOC’s water right 

of 102,000 ac-ft/yr (126 million m3

/yr) is accounted for in the Region K plan. The LCRWPG has 

evaluated several strategies that can be used to meet shortages that may occur during 

conditions similar to the drought of record when all existing water rights are fully and 

simultaneously used. Therefore, NRC concludes that continued operation of STP, Units 1 

and 2, as supported by the currently held water rights, would have no substantial effect on water 

supplies in the region. NRC further concludes that the impact on surface water resources and 

downstream water availability in the lower Colorado River from continued withdrawals during the 

license renewal term would be SMALL.

4.4 Groundwater Resources

The groundwater use and quality issues applicable to STP, Units 1 and 2, are discussed in the 

following sections and listed in Table 4–5 for Category 1 (generic) and Category 2 (site-specific) 

issues. Groundwater resources-related aspects and conditions relevant to STP, Units 1 and 2, 

are described in Sections 2.1.7.2 and 2.2.5 of this SEIS.

Table 4–5. Groundwater Resources Issues

Issues GEIS Section Category

Groundwater use conflicts (potable and service water & dewatering; 

plants that use >100 gpm) 4.8.1.1, 4.8.1.2 2 

Groundwater use conflicts (plants using cooling towers withdrawing 

makeup water from a small river) 4.8.1.3 2 

Groundwater quality degradation (saltwater intrusion) 4.8.2.1 1

Groundwater quality degradation (cooling ponds in salt marshes) 4.8.3 1

4.4.1 Generic Groundwater Issues

Section 2.2.5 of this SEIS discusses groundwater use and quality at STP. NRC did not identify 

any new and significant information with regard to Category 1 (generic) groundwater issues 

based on review of the ER (STPNOC 2010b), the public scoping process, or as a result of the 
Environmental Impacts of Operation

4-6 

environmental site audit. The NRC staff also reviewed other sources of information, such as 

applicable permits and data reports, as listed in the reference section of this SEIS chapter. The 

staff provides a list of STP permits for operation (status of compliance) in Appendix C. As a 

result, no information or impacts related to these issues were identified that would change the 

conclusions presented in the GEIS. Therefore, it is expected that there would be no impacts 

related to these Category 1 issues during the renewal term beyond those discussed in the 

GEIS. For these groundwater issues, the GElS concludes that the impacts are SMALL.

4.4.2 Groundwater Use Conflicts

This section presents the NRC staff’s review of plant-specific (Category 2) groundwater use 

conflict issues, as listed in Table 4–5. 

4.4.2.1 Plants Using Greater Than 100 gpm of Groundwater

For nuclear power plants that pump more than 100 gpm (380 L/min) of groundwater from onsite 

wells, the potential groundwater use conflict with nearby groundwater users is considered a 

Category 2 issue that requires a plant-specific assessment, as specified in 

10 CFR 51.53(c)(3)(ii)(C). In evaluating the potential impacts resulting from groundwater use 

conflicts associated with license renewal, the NRC staff uses as its baseline the existing 

groundwater resource conditions described in Sections 2.1.7.2 and 2.2.5.1 of this SEIS. These 

baseline conditions encompass the existing hydrogeologic framework and conditions (including 

aquifers) potentially affected by continued operations as well as the nature and magnitude of 

groundwater withdrawals for cooling and other purposes (as compared to relevant appropriation 

and permitting standards). The baseline also considers other downgradient or in-aquifer uses 

and users of groundwater. 

As described in Section 2.1.7.2, onsite groundwater production at STP has averaged 768 gpm 

(2,910 L/min) or 1,239 ac-ft/yr (1.5 million m3/yr) annually over the 10-year period from 2001 

through 2010. STP has a permit for five production wells completed in the Deep Chicot Aquifer 

to withdraw at a combined rate of approximately 1,860 gpm (7,040 L/min) or 3,000 ac-ft/yr 

(3.7 million m3

/yr). Of the five production wells, wells 5, 6, and 7 (as described in 

Section 2.1.7.2) feed a common header (a single collection point) that delivers water to be 

chlorinated, filtered, and stored for use by the service water system and the fire protection 

system. Each of these three wells has a design capacity of 500 gpm (1,890 L/min) at a depth of 

700 ft (210 m). The service water system includes the demineralizer system and the potable 

water supply for the plant. The common header supplied by the three production wells is also 

the primary source for makeup water to the essential cooling pond (ECP). Well 8, with a design 

capacity of 250 gpm (950 L/min) at a depth of 600 ft (180 m), supplies the Nuclear Support 

Center chill water for the building cooling tower. The Nuclear Training Facility (NTF) well, with a 

design capacity of 200 gpm (760 L/min) and a depth of 600 ft (180 m), provides fire protection 

water to the NTF (STPNOC 2010b).

Because the annual average withdrawal rate from these sources for service water and fire 

protection water is greater than 100 gpm (380 L/min), this is a Category 2 issue for the STP site. 

All five STP production wells (5, 6, 7, 8, and NTF) are located relatively near the STP site 

boundary, as shown in Figure 2–1. Coastal Plains Groundwater Conservation District (CPGCD) 

rules require that wells of 7-in. (18-cm) diameter or greater completed on adjacent lands with 

different owners must be spaced a minimum of 2,500 ft (760 m) from any other permitted or 

registered well (CPGCD 2010). Therefore, drawdown at 2,500 ft (760 m) well spacing is 

relevant to the evaluation of potential conflicts with neighboring wells.
Environmental Impacts of Operation

4-7 

The applicant performed an analysis of drawdown using the Theis non-equilibrium well 

equations (E.E. Johnson, Inc. 1966). Using representative hydraulic properties, the applicant 

calculated drawdowns of 20.0 and 20.7 ft (6.1 and 6.3 m) in the Deep Chicot Aquifer after 

40 and 60 years, respectively, for a neighboring well located 2,500 ft (760 m) from an STP 

production well pumped at 500 gpm (1,890 L/min) (STPNOC 2011c). The projected change in 

drawdown during the additional 20 years of operation is less than 1 ft (0.3 m). The NRC staff 

checked and confirmed the applicant’s drawdown estimates, as presented in Table 4–6. To 

more completely evaluate the potential change in drawdown, the NRC staff also calculated 

drawdown at distances of 1 and 5 mi (1.6 and 8 km).

Table 4–6. Projected Drawdown and Change in Drawdown in Feet 

for the Deep Chicot Aquifer for Selected Distances

Distance (a)

Aquifer Drawdown ft (m) Change in Drawdown 

ft (m) 40 years 60 years

2,500 ft (760 m) 20 ft (6.1 m) (b) 20.7 ft (6.3 m) (b) 0.7 ft (0.2 m)

1 mi (1.6 km) 17.4 ft (5.3 m) 18.1 ft (5.5 m) 0.7 ft (0.2 m)

5 mi (8 km) 11.8 ft (3.6 m) 12.5 ft (3.8 m) 0.7 ft (0.2 m)

(a) All projections assume a saturated hydraulic conductivity of 33,245 gallons per day per foot (gpd/ft), coefficient of 

storage of 0.00022 (dimensionless), and a pumping rate of 500 gpm (1,890 L/min).

(b) This is based on STPNOC 2011c. Remaining drawdown values are based on NRC staff analyses. 

The STP ER for proposed Units 3 and 4 reproduced a map showing the potentiometric surface 

(the water level that would rise in a well) in the Deep Aquifer in Matagorda County in 1967 

(STPNOC 2010c). It shows the potentiometric head (hydraulic pressure) to be between 0 and 

10 ft (3 m) below mean sea level (MSL) at the STP site. The Deep Aquifer potentiometric 

surface in 2005 reveals the potentiometric head on the site boundary near wells 5 and 6 to be 

as great as 55 ft (17 m) below MSL. Well 5 was completed in 1975, and well 6 was completed 

in 1977. By 2005, these wells had been in service for approximately 30 years, and drawdown 

was approximately 50 ft (15 m) below MSL. Piezometers completed in the Deep Chicot Aquifer 

at the site (STPNOC 2010c) indicate a steady response pumping activity since the late 1990s, 

with one piezometer relatively near production well 5 showing a near constant piezometric head 

of 50 ft (15 m) below MSL. The elevation of the upper surface of the Deep Chicot Aquifer is 

between 250 to 300 ft (76 to 91 m) below ground surface or approximately 220 to 270 ft 

(67 to 83 m) below MSL. Thus, the steady drawdown observed at the site ensures ample 

confining pressure remains in the Deep Chicot Aquifer. The drawdown observed suggests that 

a well located near the STP site boundary and one of the STP production wells could require a 

pumping lift (differential pressure applied by a pump) of approximately 50 ft (15 m) over 

conditions in 1967. This is the additional vertical distance that water would have to be pumped 

to the surface. However, the majority of this drawdown and associated pumping lift has been 

identified as regional drawdown resulting from groundwater development to the north of the STP 

site, as reflected in historical well and piezometer water well mapping (STPNOC 2009c).

The NRC staff’s analysis of drawdown using representative hydraulic properties and review of 

field data reveals that drawdown near STP production wells could influence the pumping lift of 

groundwater wells on neighboring properties. However, the drawdown at STP production wells 

from 40 years of pumping is estimated to be approximately 20 ft (6.1 m), and continued 

operation for an additional 20 years beyond the current license period would increase drawdown 
Environmental Impacts of Operation

4-8 

by less than 1 ft (0.3 m). This finding is influenced by local and regional groundwater use 

regulation as discussed above and in Section 2.2.5. The projected increase in drawdown of 

less than 1 ft (0.3 m) is a negligible impact on neighboring wells and landowners. Therefore, the 

NRC staff concludes that groundwater use conflicts from STP groundwater withdrawals during 

the license renewal term would be SMALL. 

4.4.2.2 Plants Using Cooling Towers or Cooling Ponds and Withdrawing Makeup Water 

from a Small River

Nuclear power plants using cooling towers or cooling ponds that are supplied with makeup 

water from a small river (as defined in Section 4.3.2) require a plant-specific assessment due to 

the potential impact on alluvial aquifers. The requirement for this assessment is specified by 

10 CFR 51.53(c)(3)(ii)(A). This potential impact to groundwater is considered a Category 2 

issue. The GEIS established this groundwater aspect as Category 2 because consumptive use 

of water withdrawn from a small river could adversely affect groundwater aquifer recharge. Low 

river flow conditions are of particular interest. For this groundwater use conflicts-related issue, 

the NRC staff uses the same baseline as noted in Section 4.4.2.1. 

STP, Units 1 and 2, is dependent on the lower Colorado River as the primary water source for 

the 7,000-ac (2,830-ha) MCR. Systems that have a groundwater source (e.g., service water, 

fire protection) also discharge to the MCR. The lower Colorado River meets the NRC definition 

of a small river. As noted in Section 2.2.5.1, the Shallow Chicot Aquifer discharges to the 

Colorado River southeast of the STP site. There is a relatively narrow band of an alluvial 

aquifer separating the Shallow Chicot Aquifer from the Colorado River. With the rise and fall of 

the Colorado River, the alluvial aquifer experiences bank storage. This refers to a condition 

such that when groundwater in the alluvial aquifer is higher than the river stage, the alluvial 

aquifer discharges to the river. Similarly, when river stage is higher than groundwater in the 

alluvial aquifer, the alluvial aquifer is recharged by the river. In general, the lower Colorado 

River is a gaining stream (sustained by groundwater discharges) near the STP site. This is 

because the Shallow Chicot Aquifer discharges to the alluvial aquifer, and the alluvial aquifer 

discharges to the Colorado River. During high river stage and local to the river shore, the 

groundwater elevation would increase in the alluvial and Shallow Chicot Aquifer, resulting in 

recharge to the aquifers. During low river stage, the Shallow Chicot Aquifer and the alluvial 

aquifer would resume discharging to the river.

Near the STP site, the Shallow Chicot Aquifer is used primarily for livestock watering because of 

its low yields to wells and relatively poor quality. The Deep Chicot Aquifer is separated 

hydraulically from the Shallow Chicot Aquifer by a 100- to 150-ft (30- to 46-m) thick confining 

unit, and it is the primary source of groundwater for the region due to high aquifer yields and 

good quality.

STPNOC is limited in its ability to divert water from the lower Colorado River during periods of 

low flow and can do so only after confirming the Colorado River flow at the U.S. Geological 

Survey (USGS) Bay City gaging station supports the withdrawal of surface water in accordance 

with STPNOC’s Certificate of Adjudication for water use, as discussed in Section 2.1.7.1 and 

Section 4.3.2 (STPNOC 2009d, 2010b).

In summary, the following staff findings are relevant to the issue of groundwater use conflicts on 

alluvial aquifers from STP continued operations: 

• The alluvial aquifer is limited to a relatively narrow band between the 

Colorado River and the Shallow Chicot Aquifer.
Environmental Impacts of Operation

4-9 

• The Colorado River is normally a gaining stream with the alluvial aquifer and 

Shallow Chicot Aquifer discharging to the river. During periods of low river 

flow, the alluvial aquifer and Shallow Chicot Aquifer would discharge to the 

river (the normal situation for a gaining stream). 

• The Shallow Chicot Aquifer is used for watering livestock and other low-yield, 

poor-quality applications and would not be substantially influenced by the 

bank storage effects of alluvial aquifer recharge and discharge. 

• The Deep Chicot Aquifer is the primary groundwater supply in the region, and 

it discharges to the lower Colorado River estuary and Matagorda Bay 

approximately 5 mi (8 km) downstream of STP (discussed in Section 2.2.5).

• STP is limited through its Certificate of Adjudication and management plan 

regarding diversion of lower Colorado River water during low flow (discussed 

in Section 2.1.7.1 and Section 4.3.2).

Based on the information above, the NRC staff concludes that continued withdrawals of surface 

water (the Colorado River) for the operation of STP, Units 1 and 2, during low-flow periods 

would have a SMALL impact on recharge to the alluvial aquifer during the license renewal term.

4.4.3 Groundwater Quality

As described in Section 4.4.1, the NRC staff did not identify any new and significant information 

with regard to Category 1 (generic) groundwater issues. As part of its assessment, the staff 

specifically reviewed information relating to the current state of knowledge regarding 

groundwater quality downgradient of the MCR and underlying the STP protected area, as 

summarized in this section. In evaluating the potential impacts on groundwater quality 

associated with license renewal, the NRC staff uses as its baseline the existing groundwater 

conditions described in Section 2.2.5.2 of this SEIS. These baseline conditions encompass the 

existing quality of groundwater potentially affected by continued operations (as compared to 

relevant state or U.S. Environmental Protection Agency (EPA) primary drinking water standards

(DWS)) as well as the current and potential onsite and offsite uses and users of groundwater for 

drinking and other purposes. The baseline also considers other downgradient or in-aquifer uses 

and users of groundwater. 

Elevated concentrations of tritium have been observed in groundwater adjacent to the MCR and 

in groundwater underlying the protected area of STP, Units 1 and 2, as described in 

Section 2.2.5.2. The MCR is unlined and water from the reservoir seeps into the Upper Shallow 

Aquifer. Systems within the protected area have released liquids containing tritium to 

groundwater.

Regarding non-radioactive contaminants in the MCR, total dissolved solids (TDS) is an indicator 

contaminant. The NRC staff anticipates that seepage from the MCR to the Upper Shallow 

Aquifer would initially have the same TDS concentration as the MCR. STPNOC’s estimate of 

the median TDS concentration in the MCR from operation of STP, Units 1 and 2, is 

approximately 2,000 mg/L (NRC 2011b). Locally, groundwater from the Shallow Aquifer is 

described as being slightly saline because TDS concentrations are above 1,000 mg/L 

(i.e., slightly saline waters have TDS ranges of 1,000 to 3,000 mg/L). Onsite wells completed in 

the Shallow Chicot Aquifer have an average TDS concentration of 1,200 mg/L 

(STPNOC 2010c). Accordingly, the Shallow Aquifer is used locally to water livestock, and it is 

not a freshwater supply. The NRC staff concludes that given a long-term local increase of TDS 

concentration to 2,000 mg/L, the groundwater TDS concentration would remain in the range 
Environmental Impacts of Operation

4-10

associated with slightly saline waters. Thus, the potential future TDS level is consistent with the 

existing groundwater quality and its current use as a source of water for livestock. Any impacts 

from this change in groundwater quality would be localized because the groundwater plumes 

originating from the MCR are local to the STP site and the region immediately downgradient of 

the site to the lower Colorado River.

Regarding radioactive contaminants in the MCR, tritium is an indicator contaminant. Tritium 

releases occur to the Upper Shallow Chicot Aquifer from the MCR via seepage through the 

reservoir floor. Historical monitoring data for the MCR water (inside the MCR) show a peak 

tritium concentration of 17,410 picocuries per liter (pCi/L) in 1996 and values less than 

14,000 pCi/L since then (STPNOC 2010b, 2010c). A relief well (no. 701) monitored since 1995 

showed a peak tritium concentration of 7,672 pCi/L in 1998 and values less than 7,000 pCi/L 

since then. Tritium activity in an onsite monitoring well (MW-251) completed in the Shallow 

Chicot Aquifer showed a peak in year 2000 of approximately 8,000 pCi/L and lower values 

before and after (NRC 2011b; STPNOC 2010a, 2013b). However, in mid-2012, a spike to 

8,600 pCi/L was observed in MW-251 before levels declined once again (STPNOC 2013b). 

Monitoring continues to show that levels of tritium in the Shallow Chicot Aquifer around the MCR 

originate from the liquids discharged to the MCR and are below the EPA primary DWS of 

20,000 pCi/L (40 CFR Part 141). The staff also concludes that tritium concentrations in the 

Shallow Chicot Aquifer, resulting from seepage from the MCR, are bounded by the tritium 

concentration in the MCR waters. Thus, the observed peak tritium concentration of 

17,410 pCi/L, and more recent levels of 14,000 pCi/L, ensures that tritium concentrations in 

groundwater downgradient of the MCR will be below the EPA primary DWS. Further, as noted 

in Section 2.2.5.2, the Deep Chicot Aquifer is separated from the Shallow Chicot Aquifer by a 

zone of predominantly clay material 100 to 150 ft (30 to 46 m) thick. The Deep Chicot Aquifer is 

the primary source of groundwater for the region, and tritium has not been detected in the Deep 

Chicot Aquifer (MACTEC 2009).

As a result of STPNOC’s participation in the Nuclear Energy Institute’s (NEI) Groundwater 

Protection Initiative (NEI 2007), data exist on tritium levels in groundwater, and a report was 

issued that compiled all information about groundwater and releases to groundwater in the STP, 

Units 1 and 2, protected area (MACTEC 2009). A peak tritium concentration around 

15,000 pCi/L was observed in the Upper Shallow Chicot Aquifer beneath the protected area in 

2006. Sampling at the location of that peak concentration has shown a continuous decline in 

tritium concentration with a concentration of 678 pCi/L observed in 2012. All measured tritium 

levels in groundwater within the protected area are below the EPA primary DWS 

(i.e., 20,000 pCi/L) (see Section 2.2.5.2).

Three possible sources of tritium in groundwater within the protected area have been identified 

as seepage from the MCR, leaks of the TDS pipeline system, and discharge to the ground from 

the turbine steam trap drains or steam condensate lines. Tritium levels in groundwater 

originating in the MCR are bounded, as described above, and will be less than the EPA primary 

DWS. STPNOC has noted that the TDS pipeline system and the steam condensate line 

releases could have a maximum tritium concentration of less than 90,000 pCi/L 

(STPNOC 2011c). Releases to groundwater in the vicinity of the Units 1 and 2 reactors move 

downward from the Upper into the Lower Shallow Chicot Aquifer and then laterally to the east 

and southeast in the Lower Shallow Chicot Aquifer to the STP site boundary (NRC 2011b). As 

described in Section 2.2.5.2, the groundwater travel time from the protected area to the STP site 

boundary east of the protected area is approximately 100 years. This represents over 

eight half-lives of tritium decay; therefore, releases at the maximum level would decay to 

concentrations below the EPA primary DWS before leaving the STP site. The NRC staff has 
Environmental Impacts of Operation

4-11

evaluated the releases inside the protected area, as well as relevant groundwater monitoring 

data. The staff concludes that no release is occurring from an unidentified pathway (based on 

accounting of releases from available records), and there is no substantial adverse impact on 

drinking water (the staff evaluates human health issues in Section 4.8).

In addition to the foregoing, the following staff findings are relevant to the issue of groundwater 

quality impacts:

• Groundwater in the Shallow Chicot Aquifer will remain slightly saline and 

suitable to its current use for watering livestock.

• Tritium levels in the Shallow Chicot Aquifer resulting from seepage from the 

MCR will not exceed the EPA primary DWS.

• Tritium has not been detected in the Deep Chicot Aquifer, which is the 

primary groundwater source in the region.

• Tritium levels in the Shallow Chicot Aquifer resulting from leaks and 

discharges inside the STP protected area are currently below the EPA DWS, 

and long-term tritium levels leaving the STP site from such releases would be 

below the EPA DWS.

In conclusion, based on this information—including the staff’s review of seepage from the MCR 

and the review of releases of liquids containing tritium within the protected area of STP, Units 1 

and 2—the NRC staff concludes that groundwater contaminant plumes have not altered current 

groundwater use in the region downgradient of the STP site. The staff further concludes that 

groundwater-quality impacts would remain SMALL during the license renewal term.

4.5 Aquatic Resources

Sections 2.1.6 and 2.2.5 describe the STP cooling system and aquatic environment. 

Section 2.2.7.1 describes the protected aquatic resources that could occur in the vicinity of STP 

and associated transmission lines. Category 1 and Category 2 issues related to aquatic 

resources applicable to STP are discussed below and listed in Table 4–7. 

Table 4–7. Aquatic Resource Issues

Issues GEIS Section Category

For all plants

Accumulation of contaminants in sediments or biota 4.2.1.2.4 1

Entrainment of phytoplankton & zooplankton 4.2.2.1.1 1

Cold shock 4.2.2.1.5 1

Thermal plume barrier to migrating fish 4.2.2.1.6 1

Distribution of aquatic organisms 4.2.2.1.6 1

Premature emergence of aquatic insects 4.2.2.1.7 1

Gas supersaturation (gas bubble disease) 4.2.2.1.8 1

Low dissolved oxygen in the discharge 4.2.2.1.9 1
Environmental Impacts of Operation

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Issues GEIS Section Category

Losses from predation, parasitism, & disease among organisms 

exposed to sublethal stresses 4.2.2.1.10 1 

Stimulation of nuisance organisms 4.2.2.1.11 1

For Plants with Cooling Pond Heat-Dissipation Systems

Entrainment of fish & shellfish in early life stages 4.1.2 2

Impingement of fish & shellfish 4.1.3 2

Heat shock 4.1.4 2

4.5.1 Generic Aquatic Ecology Issues

The NRC staff did not identify any new and significant information related to the Category 1 

issues listed above during the review of STPNOC’s ER, the site audit, or the scoping process 

that would change the conclusions presented in the GEIS (the NRC staff also reviewed other 

sources of information, such as applicable permits and data reports, as listed in the reference 

section of this SEIS chapter). Therefore, there is no impact related to these issues beyond 

those discussed in the GEIS. For these issues, the GEIS concluded that the impacts are 

SMALL. 

4.5.2 Entrainment and Impingement

Entrainment and impingement of aquatic organisms are site-specific (Category 2) issues for 

assessing the impacts of license renewal at plants with cooling pond heat-dissipation systems. 

Entrainment is the taking in of organisms with a plant’s cooling water intake. The organisms 

involved are generally of small size, dependent on the screen mesh size, and include phytoand zooplankton, fish eggs and larvae, shellfish larvae, and many other forms of aquatic life. 

Impingement is the entrapment of organisms against the cooling water intake screens.

A particular species can be subject to both impingement and entrainment if some individuals are 

impinged on screens while others pass through and are entrained (EPA 1977). Section 316(b) 

of the Clean Water Act (CWA) (33 United States Code (U.S.C.) §1326(b)) requires that “[a]ny 

standard established pursuant to Section 1311 of this title or Section 1316 of this title and 

applicable to a point source shall require that the location, design, construction, and capacity of 

cooling water intake structures reflect the best technology available for minimizing adverse 

environmental impact.”

At STP, organisms maybe impinged or entrained at two locations. Organisms that inhabit the 

lower Colorado River may be impinged or entrained when water is drawn through the reservoir 

makeup pumping facility (RMPF) from the Colorado River into the MCR. Organisms that inhabit 

the MCR may be impinged or entrained when water is drawn through the cooling water intake 

structure (CWIS) from the MCR to the cooling water system.

The adverse environmental impacts of cooling water intakes occur through both impingement 

and entrainment. Heat, physical stress, or chemicals used to clean the cooling system may kill 

or injure the entrained organisms. Exhaustion, starvation, asphyxiation, descaling, and physical 

stresses may kill or injure impinged organisms. STPNOC survey data in the MCR indicate that 

entrained organisms from the lower Colorado River can survive the stresses of the intake 
Environmental Impacts of Operation

4-13

system at the RMPF and colonize the MCR (ENSR 2008a, 2008b). However, entrainment and 

colonization of the MCR removes these organisms from the rest of the ecosystem in the region. 

Entrained organisms that pass through the CWIS into the plant’s cooling system are subject to 

mechanical, thermal, and toxic stresses. Therefore, survival is unlikely.

This section uses a retrospective assessment of the present and past impacts to the (terrestrial 

or aquatic) ecosystem resulting from plant operation in order to provide a prospective 

assessment for the future impacts over the license renewal term (i.e., the remainder of the 

present term plus an additional 20 years). The timeframe and geographic extent of the 

assessment are two related parts of the scoping process that bounds the impact analysis. The 

timeframe defines how far back and how far forward the analysis will extend. In assessing the 

level of impact, the staff looks at the projected effects in comparison to a baseline condition.

In agreement with National Environmental Policy Act (NEPA) guidance (CEQ 1997a), the 

baseline of the assessment is the condition of the resource without the action (i.e., under the 

no-action alternative). Under the no-action alternative, the plant would shut down, and the 

resource would conceptually return to its condition without the plant, which is not necessarily the 

same as the condition before the plant was constructed. The timeframe of analyses for 

ecological resources extends far enough into the past to understand trends and to determine 

whether the resource is stable, which the NRC definitions of impact levels require. For 

assessing direct and indirect impacts, the geographic boundaries depend on the biology of the 

species under consideration.

Because impingement and entrainment are fundamentally linked, the NRC staff determined that 

effects of each should be assessed using an integrated approach. The NRC staff employed a 

weights-of-evidence (WOE) approach to evaluate the effects of impingement and entrainment 

on the aquatic resources in the lower Colorado River and the MCR. NRC employed this 

approach because EPA recommends a WOE approach for ecological risk assessments 

(EPA 1998). WOE is a useful tool due to the complex nature of assessing risk (or impact), and 

NRC has employed this approach in other evaluations of the effects of nuclear power plant 

cooling systems on aquatic communities (NRC 2010, 2011i).

Menzie et al. (1996) defines WOE as “the process by which multiple measurement endpoints 

are related to an assessment endpoint to evaluate whether significant risk of harm is posed to 

the environment.” In this modified WOE approach, the NRC staff examined five lines of 

evidence to determine if operation of the STP cooling system has the potential to cause adverse 

impacts to fish and shellfish near STP. The first line of evidence is impingement and 

entrainment studies at the RMPF during the initial filling and subsequent intermittent withdraw of 

water from the Colorado River to the MCR (McAden 1984, 1985). The second line of evidence 

is impingement and entrainment studies at the CWIS from 2007 through 2008 during the 

withdraw of water from the MCR through the circulating water system for STP, Units 1 and 2 

(ENSR 2008a). The third line of evidence includes engineering designs and operational 

procedures to limit impingement and entrainment. The fourth line of evidence includes reviews 

by other regulatory agencies, such as EPA and the Texas Commission on Environmental 

Quality (TCEQ). The fifth line of evidence includes survey data of fish and shellfish populations 

prior to and during operations within the Colorado River.

Line of Evidence Number 1: Impingement and Entrainment Studies on the Colorado River

The NRC staff evaluated the potential impacts from impingement and entrainment during water 

withdrawal from the Colorado River by examining impingement and entrainment studies 

from 1983 to 1984. McAden et al. (1984, 1985) conducted studies at the RMPF when STPNOC 
Environmental Impacts of Operation

4-14

initially filled the MCR with Colorado River water. NRC (1986) assessed the environmental 

impacts of impingement and entrainment for the initial operating license for STP, Units 1 and 2.

McAden et al. (1984, 1985) conducted studies to estimate entrainment impacts by collecting 

surface plankton samples in front of the RMPF. McAden used a hand-towed 0.5-m 

(20-in. mouth diameter) ichthyoplankton net with 0.5-mm (0.02-in.) square mesh and swept the 

hand tow parallel to the front wall of the pump structure. The most commonly collected species 

included the zoeae and juveniles of Harris mud crabs (Rhithropanopeus harrisii), river shrimp 

(Macrobrachium ohione), and white shrimp (Litopenaeus setiferus), as shown in Table 4–8. 

McAden collected the eggs and larvae of two fish species—bay anchovy (Anchoa mitchilli) and 

mosquito fish (Gambusia affinis). McAden also conducted plankton tows in the Colorado River 

near the RMPF. The most commonly collected species of fish eggs and larvae included bay 

anchovy, Gulf menhaden (Brevoortia patronus), and Atlantic croaker (Micropogonias undulatus). 

Section 2.2.5.1 provides addition details regarding fish egg and larvae sampling in the Colorado 

River.

Based on the entrainment study by McAden et al. (1984, 1985), NRC (1986) estimated that 

entrainment losses would be approximately 10 percent of the organisms passing the RMPF. 

This value represents the loss of organisms in the influence of the tidal flow in the river and 

does not represent the entire populations of those species in the lower Colorado River.

NRC (1986) determined that the systems along the Texas Gulf coasts and the area influenced 

by the RMPF are not unique. In addition, NRC (1986) determined that species commonly 

caught in near the RMPF by McAden are ubiquitous (widespread or common) and abundant 

along the Texas and Gulf coasts. The reproductive potential (fecundity) for these species is 

high; therefore, the larvae entrained are a small portion of the total larvae produced by adult 

females for most species (NRC 2011b). In addition, most makeup water withdrawal would 

occur during high river flow conditions, which is when the salinity and concentrations of 

estuarine and marine organisms would be lowest. Therefore, NRC (1986) concluded that 

entrainment losses for the species collected by McAden (1984, 1985) would not constitute a 

significant impact to their respective populations.

ENSR Corporation (2008a) indicates that many individuals of numerous species survived 

entrainment at the RMPF and inhabit the MCR. While these organisms survived entrainment, 

the entrainment, overall, has led to a loss of the organisms in the Colorado River, and these 

organisms no longer contribute to the riverine ecosystem.

Table 4–8. Number (per 100 m3

) of Macrozooplankton and Ichthyoplankton Collected in 

Plankton Samples in Front of the RMPF from 1984 and 1985

Common Name Scientific Name Aug-83(a) Sept-83(b) Sept-84(c) Total 

% of 

Total 

bay anchovy Anchoa mitchilli 51.3 0 0 51.3 1

bivalves-juveniles Pelecypoda 10.3 28.3 0 38.6 1

blue crab-juvenile Callinectes sapidus 62.8 14.1 0 76.9 2

crabs-megalopa Callinectes spp. 115 0 0 115 3

glass shrimp Palaemonetes paludosus 0 14.9 0 14.9 <1

Harris mud crab Rhithropanopeus harrisii 184.9 1,461.4 695.9 2,342.2 60
Environmental Impacts of Operation

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Common Name Scientific Name Aug-83(a) Sept-83(b) Sept-84(c) Total 

% of 

Total 

mosquito fish Gambusia affinis 23.3 14.9 0 38.2 1 

ghost shrimp Callianassa spp. 0 0 51.4 51.4 1 

river shrimp Macrobrachium ohione 609.3 29 0 638.3 16

white shrimp Litopenaeus setiferus 222.2 312.8 0 535 14

unidentified fish spp. 0 0 12.9 12.9 <1

Total 1,279.1 1,875.4 760.2 3,914.7

(a) Samples collected on August 9–10, 1983, at 1100, 1640, 2230, and 0450

(b) Samples collected on September 15–16, 1983, at 1100, 1705, 2250, and 0545

(c) Samples collected on September 6, 1984, at 0020, 0500, 1030, and 1615

Source: McAden 1984, 1985

McAden et al. (1984, 1985) also conducted impingement studies by washing all organisms off 

two intake screen and filtering them through a dip net with a 0.25-in (6.4-mm) mesh. Each 

sample period was 30 minutes. McAden (1984, 1985) collected three samples within 24 hours 

during each week that pumping occurred. The most commonly impinged species included blue 

crab (61 percent), river shrimp (18 percent), and white shrimp (10 percent), as shown in Table 

4–9. Impinged fish included one crevalle jack (Caranx hippos), one green sunfish (Lepomis 

cyanellus), and one inland silverside (Menidia beryllina). Because the impingement study 

collected so few fish, NRC (1986) predicted the most likely fish to be impinged based on size 

(which is related to swim speed) and the density and abundance of the species near the RMPF. 

NRC (1986) predicted Gulf menhaden to be the most commonly impinged species (65 percent), 

followed by Atlantic croaker (16 percent), bay anchovy (10 percent), and striped mullet 

(8 percent). NRC (1986) concluded that impingement losses would have a minor effect on the 

biota of the Colorado River because the commonly impinged species are ubiquitous, abundant 

habitat for these species occurs along the Texas and Gulf coasts, and the design elements of 

the RMPF would reduce impingement losses.

STPNOC has not conducted impingement and entrainments studies on the Colorado River 

since its 1983 to 1984 study (STPNOC 2010b, 2010c). Since 1984, the U.S. Army Corps of 

Engineers (USACE) completed the mouth of the Colorado River project, increasing the flow 

between the Colorado River and Matagorda Bay (USACE 2005; Wilber and Bass 1998). As 

discussed below in the aquatic survey section (line of evidence number 5), the diversity of 

aquatic species and the presence of estuarine-marine species has increased since the 1970s. 

However, ENSR (2008b) found that the majority of the species most likely to be impinged 

(e.g., Gulf menhaden, Atlantic croaker, and striped mullet) continue to be the most common 

species of fish collected around the RMPF and would likely continue to be the most common 

species impinged during the license renewal term.
Environmental Impacts of Operation

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Table 4–9. Invertebrates and Fish Impinged at the RMPF during 1983–1984 Studies

Common Name Scientific Name July-83(a) Aug-83(b) Sept-83(c) Sept-84(d) Total 

% of 

Total

blue crab Callinectes sapidus 69 44 4 6 123 61

crevalle jack Caranx hippos 1 0 0 0 1 <1

glass shrimp

Palaemonetes 

paludosus 14 1 0 0 15 7

grass shrimp

Palaemonetes 

kadiakensis 1 1 0 0 2 1

green sunfish Lepomis cyanellus 1 0 0 0 1 <1

inland silverside Menidia beryllina 1 0 0 0 1 <1

pink shrimp

Farfantepenaeus 

brasiliensis 0 0 0 1 1 <1

Palaemonidae 

shrimp Palaemonidae spp. 2 0 0 0 2 1

river shrimp 

Macrobrachium 

ohione 28 4 1 4 37 18

white shrimp Litopenaeus setiferus 0 3 13 4 20 10

Total 117 53 18 15 203

(a) Samples collected on July 13–14, 1983, at 1329, 2100, and 0511; July 21–22, 1983, at 1315, 2110, 0505; and 

July 27–28, 1983, at 1400, 2230, and 0626.

(b) Samples collected on August 9–10, 1983, at 1300, 2100, and 0500.

(c) Samples collected on September 15–16, 1983, at 1414, 2205, and 0615.

(d) Samples collected on September 5–6, 1984, at 1910, 0300, and 1104.

Source: McAden 1984, 1985

Line of Evidence Number 2: Impingement and Entrainment Studies on the Main Cooling 

Reservoir

STP conducted impingement and entrainment studies at the CWIS on the MCR in May 2007 

through April 2008 (ENSR 2008a). The objective of the study was “to characterize the aquatic 

species within the MCR, and to evaluate impingement and entrainment impacts to establish, to 

the extent possible, relationships between the presence of aquatic organisms and the current 

(STP, Units 1 and 2) intake design and operating parameters” (ENSR 2008a).
Environmental Impacts of Operation

4-17

ENSR (2008a) collected entrainment samples over a 24-hour period, twice per month from May 

through September and once per month from October through April. ENSR collected 

entrainment samples by placing 0.363-mm (0.014-in.) plankton nets behind the trash bars at the 

CWIS. ENSR pumped water from a depth of approximately 12 ft (3.7 m) through a buffering 

chamber at flows up to 10,800 gallons per hour or 180 gpm. ENSR operated the pumps four 

times per day, for approximately 2 hours per event, for a volume of 100 m3 (3,500 ft3

) of water 

per 24-hour period.

ENSR (2008a) collected 207,696 organisms representing nine different fish families and 

12 different classes of invertebrates (Table 4–10). The most commonly impinged taxa included 

Harris mud crab (68 percent) and unidentified decapod zoea (or free swimming larvae) 

(15 percent). Ichthyoplankton, or fish eggs and larvae, comprised less than 1 percent of all 

entrained organisms. ENSR reported the highest entrainment rates from April through June and 

the lowest from December through March. Entrainment of threadfin shad and mud crabs was 

highest in late spring and summer, and entrainment of silversides was highest in summer.

Table 4–10. Aquatic Species Collected during Entrainment 

Sampling in the MCR’s CWIS for Units 1 and 2, 2007–2008

Common Name Taxon Total Number % of Total

Finfish

anchovy Anchoa spp. 30 <1

clupeid Clupeidae 544 <1

fish egg 418 <1

goby Gobiidae 61 <1

perch-like fish Perciformes 6 <1

naked goby Gobiosoma bosc 5 <1

needlefish Belonidae 3 <1

silversides Atherinidae 201 <1

wrasse Labridae 3 <1

Invertebrates 

amphipod Amphipoda 145 <1

bivalve Mollusca 1 <1

brachyuran decapod (zoea) Brachyura 353 <1

copepod Copepoda 6,588 3

decapod (mud crabs) Panopeidae 10,798 5

decapod (zoea) Decapoda 31,919 15

fish lice Copepoda 399 <1

harpacticoid copepod Copepoda 12,212 6

Harris mud crab Rhithropanopeus harrisii 140,192 68
Environmental Impacts of Operation

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Common Name Taxon Total Number % of Total

insect Insecta 24 <1

midge Diptera 110 <1

mite or ticks Acari 12 <1

mysid shrimp Mysida 2,660 1

polychaete Annelida 4 <1

seed shrimp Ostracoda 78 <1

shrimp Caridea 1 <1

tongue biters Isopoda 16 <1

water flea Cladocera 800 <1

unidentified 113 <1

Total 207,696

Source: ENSR 2008a

ENSR (2008a) collected impingement samples over a 24-hour period, twice per month from 

May through September and once per month from October through April. ENSR collected 

samples by placing a metal-framed net fitted with a 0.25-in. (6.4-mm) nylon mesh net within the 

sluiceway that connects the CWIS screen wash system and the debris basket.

ENSR (2008a) collected a total of 3,982 organisms representing 25 finfish and 7 invertebrate 

species (Table 4–11). The most commonly impinged species includes threadfin shad 

(Dorosoma petenense) (42 percent), blue crab (24 percent), mud crab (24 percent), Atlantic 

croaker (5 percent), and white shrimp (3 percent). Blue crab impingement was highest during 

the months of May, June, and July, and threadfin shad impingement was highest during the 

months of January and March. ENSR did not report any other temporal trends for individual 

species or all species combined.

Table 4–11. Aquatic Species Collected during Impingement 

Sampling in the MCR’s CWIS for Units 1 and 2, 2007–2008

Common Name Scientific Name Total Number % of Total

Finfish

American eel Anguilla rostrata 1 <1

Atlantic croaker Micropogonias undulatus 182 5

bay anchovy Anchoa mitchilli 3 <1

bay whiff Citharichthys spilopterus 2 <1

black drum Pogonias cromis 2 <1

blue catfish Ictalurus furcatus 6 <1

bluegill Lepomis macrochirus 9 <1
Environmental Impacts of Operation

4-19

Common Name Scientific Name Total Number % of Total

channel catfish Ictalurus punctatus 4 <1

common carp Cyprinus carpio carpio 2 <1

freshwater drum Aplodinotus grunniens 5 <1

freshwater goby Ctenogobius shufeldti 2 <1

gizzard shad Dorosoma cepedianum 2 <1

goby Gobiidae spp. 8 <1

Gulf menhaden Brevoortia patronus 2 <1

inland silverside Menidia beryllina 5 <1

ladyfish Elops saurus 1 <1

naked goby Gobiosoma bosc 13 <1

needlefish Strongylura exilis 2 <1

rough silverside Membras martinica 2 <1

sand seatrout Cynoscion arenarius 3 <1

sharptail goby Oligolepis acutipennis 2 <1

sheepshead Archosargus probatocephalus 1 <1

speckled worm eel Myrophis punctatus 1 <1

spot croaker Leiostomus xanthurus 1 <1

threadfin shad Dorosoma petenense 1,668 42

Invertebrates 

blue crab Callinectes sapidus 944 24

brown shrimp Farfantepenaeus aztecus 10 <1

grass shrimp Paleemonetes pugio 33 <1

lesser blue crab Callinectes similis 3 <1

Harris mud crab Rhithropanopeus harrisii 953 24

river shrimp Macrobrachium ohione 3 <1

white shrimp Litopenaeus setiferus 106 3

Other

flat-headed snake Tantilla gracilis 1 <1

Total 3,982
Environmental Impacts of Operation

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Common Name Scientific Name Total Number % of Total

Source: ENSR 2008a

Line of Evidence Number 3: Engineered Design and Operational Conditions

EPA recently published a proposed rule that describes multiple approaches to reduce 

impingement and entrainment mortality at existing cooling water intake structures. These 

approaches include flow reduction, or reducing the total amount of water withdrawn; intake 

velocity; technologies to exclude organisms and to collect and return organisms to the water 

body; and intake location and timing of withdrawals (76 FR 22174). The RMPF on the Colorado 

River and the CWIS on the MCR incorporate several of these approaches.

Flow Reduction. Reducing the intake flow reduces the amount of water withdrawn from water 

bodies to be cycled through the cooling system, which likely reduces the amount of aquatic 

organisms that would be drawn through the intake structure and subject to impingement and 

entrainment. STP uses a cooling pond-based heat-dissipation system that withdraws and 

discharges cooling water to the MCR. The MCR is similar to a closed-cycle cooling system 

since the water in the reservoir continues to circulate from the MCR, into the plant, and back 

again. STP intermittently draws water from the Colorado River to compensate for water loss 

from evaporation and seepage from the MCR. Depending on the quality of the makeup water, 

closed-cycle recirculating cooling water systems can reduce consumptive water use by 

96 to 98 percent of the amount that the facility would use if it employed a once-through cooling 

system (69 FR 41576). 

Reduced Intake Velocity. Water velocity associated with the intake structure greatly influences 

the rate of impingement and entrainment. The higher the approach or through-screen velocity 

or both, the greater the number of organisms impinged or entrained. At an approach velocity of 

0.5 ft/s (0.15 m/s) or less, most fish can swim away and escape from the intake current 

(66 FR 65274). The maximum design approach velocity in front of the traveling screens at the 

RMPF is approximately 0.5 ft/s, based on a maximum pumping rate of approximately 

538,000 gpm (2,040 m3

/min) (STPNOC 2008a, 2008c, 2010c).

Technologies to exclude organisms and to collect and return organisms to the water body. The 

RMPF has several technologies that help exclude organisms from becoming impinged or 

entrained. The RMPF has coarse trash racks with 4-in. (10-cm) spacing between bars, which 

would impede larger organisms from entering the intake system (STPNOC 2010c). After 

passing through trash racks, water flows through traveling screens with a 3/8 in. (9.5 mm) mesh 

(STPNOC 2010c). The space between the trash racks and the traveling screens allow fish to 

swim downstream and exit the intake structure (STPNOC 2010c). Fish collected or washed 

from the traveling screens can also return to the river via a sluice and fish bypass pipe. The 

discharge point of the fish bypass system is at the downstream end of the intake structure, 

approximately 2 ft (0.6 m) below normal water elevation (STPNOC 2010c).

During high-flow conditions, the accumulation of debris on the traveling screens is too high to 

open the fish bypass system, and screenwash discharge is directed to the sluice trench catch 

baskets rather than back to the river. Generally, the fish bypass system is closed when river 

flows are greater than 4,000 cfs (100 m3

/s), and the system is occasionally closed when flows 

are greater than 2,000 cfs (60 m3

/s), which has occurred from 2001 to 2006, 7 percent of the 

time (STPNOC 2008a, 2008c, 2010c). Operators at the RMPF are required to monitor for 

increased impingement rates on the traveling screens, and operators evaluate relevant 

factors—such as river flow, salinity, and observations of impingement—to determine whether 

pumping should continue (STPNOC 2008a, 2008c, 2010c).
Environmental Impacts of Operation

4-21

Intake Location and Time of Withdrawals. Location of the intake system is another design factor 

that can affect impingement and entrainment because water drawn from areas with lower 

biological productively is less likely to include organisms that could be impinged or entrained. 

The RMPF is located on the Colorado River, which is designated as a tidal stream and includes 

essential fish habitat (EFH) for Federally managed fish and shellfish species (GMFMC 2004). 

Locating intake systems in such areas with sensitive biological productivity can negatively affect 

aquatic life (69 FR 41576). However, the area of the river where the RMPF is situated has 

fewer organisms and less species richness than the downstream segment of the river, closer to 

the GIWW (ENSR 2008b).

STPNOC designed the RMPF to position the traveling intake screens parallel to the flow in the 

river, or “flush” to the river bank with no projecting structures that create eddies and 

countercurrents that would cause entrapment (NRC 1986; STPNOC 2010c). Most organisms 

likely to be entrained or entrapped would occur in higher densities in the main river channel. 

They are less likely to be removed from the river by an intake facility sited on the shoreline 

(NRC 2011b). Entrapment of aquatic organisms in a restricted area (e.g., in the sedimentation 

basin between the RMPF intake screens and the pumps and in the MCR) can lead to 

congregation of the organisms, and, if environmental conditions change, the organisms may be 

harmed. Under such conditions, entrapment can increase impingement of aquatic organisms.

Operational procedures for the RMPF also minimize impingement and entrainment because 

STPNOC intermittently draws water from the Colorado River for Units 1 and 2, and pumping 

occurs during periods of lower biological productivity. For example, STPNOC (2010b) noted 

that most withdrawals would occur during periods of high river flow. Pumping at high-flow 

conditions minimizes impacts to aquatic organisms in the water column because the organisms 

are likely to remain in the river flow and unlikely to be caught in the influence of the water being 

pumped into the RMPF located on the shoreline (STPNOC 2008a, 2008c, 2010b, 2010c). In 

addition, periods of high river flow (fall through spring) generally correlate with lower biological 

productivity when less young and estuarine-marine organisms are present (NRC 1986; 

STPNOC 2010b). During the 2007 to 2008 aquatic ecology studies in the Colorado River, fish 

density (as expressed in the catch per unit effort) was lowest during high river flow conditions 

and when salinity was lowest (ENSR 2008b; STPNOC 2008a, 2008c). Salinity can be an 

indicator of an influx of estuarine species moving up the river from the GIWW.

Line of Evidence 4: Other Regulatory Reviews

Section 316(b) of the CWA requires that the location, design, construction, and capacity of 

cooling water intake structures reflect the best technology available for minimizing adverse 

environmental impacts. As part of STPNOC’s original National Pollutant Discharge Elimination 

System (NPDES) permit application, in a letter dated June 28, 1982, STPNOC provided EPA 

with detailed information on the design and operation of the RMPF (STPNOC 2010b). Based 

on this information, EPA concluded that “the intake structure is approved by Best Available 

Technology in accordance with Section 316(b) of the CWA” (EPA 1985).

TCEQ has administered STPNOC’s Texas Pollutant Discharge Elimination System (TPDES) 

permit since 1998, when EPA delegated authority to the State of Texas to administer the State’s 

permit program. STPNOC submitted a TPDES permit renewal application by letter dated 

May 24, 2007. Included in this application was a description of how the cooling water system is 

a closed-cycle recirculating system and, as such, meets the best available technology standard 

for minimizing adverse environmental impacts (STPNOC 2010b). For example, STPNOC noted 

that the MCR recycles water for heat-dissipation and is not a water of the U.S. or a water of the 

State. TCEQ Water Quality Division concurred that the STP cooling system operates as a 
Environmental Impacts of Operation

4-22

closed-cycle recirculating system and that the MCR is not a water of the State (TCEQ 2007). 

Neither EPA nor the State of Texas has requested additional studies from STPNOC in regards 

to a 316(b) determination (STPNOC 2010b).

Line of Evidence Number 5: STP Survey Data on the Colorado River

Impingement and entrainment from current operations of the RMPF have removed individuals 

from the Colorado River ecosystem. One method to determine the impacts to aquatic resources 

from operation of the RMPF is to compare the species abundance and diversity prior to and 

during operations. ENSR (2008b) compared the aquatic community in the Colorado River using 

the results of field studies from 1974 (HPLC 1974), 1983 and 1984 (McAden 1984, 1985), and 

2007 through 2008 (ENSR 2008b). The 1970s studies were conducted in support of the 

construction permit for STP, Units 1 and 2. McAden (1984, 1985) conducted studies in support 

of the operating license for STP, Units 1 and 2. ENSR (2008b) sampled portions of the 

Colorado River in support of the combined license (COL) for proposed Units 3 and 4. 

Section 2.2.5.1 provides additional details of these studies. Because the sampling locations 

and gear types varied with each study, it can be difficult to determine whether changes over 

time are due to plant operations, other anthropogenic or environmental changes, or study 

methods.

ENSR (2008b) compared species richness from trawl surveys conducted in 1974, 1983, 

and 2007 through 2008. Species richness was generally higher in 2007 through 2008 

compared to earlier surveys (ENSR 2008b), as shown in Figure 4–1. For example, species 

richness in Segment C, which is closest to the RMPF, increased from 12 in the 1974 study to 

24 in 2007 through 2008 study. Because STPNOC gathered data for only 2 or 3 years in each 

segment of the river, it is unclear whether the change in diversity is part of a long-term temporal 

change or whether the physical conditions in the river (e.g., lower salinity in the 1970s), or 

another variable, contributed to the different levels of diversity in 1974 compared to 2007 and 

2008.
Environmental Impacts of Operation

4-23

Figure 4–1. Species Richness of Aquatic Species Captured in Trawl Surveys

from 1974, 1983, and 2007 through 2008

ENSR (2008b) calculated the Jaccard coefficients of community similarity to determine 

similarities between the samples collected over time in similar reaches of the lower Colorado 

River based on the presence or absence of taxa. For this measure, as the coefficient 

approaches 1.0, the more taxa in the two samples are the same. Conversely, as the coefficient 

approaches zero, the samples have fewer taxa in common. For samples collected in the area 

closest to the RMPF (Segment C), the Jaccard coefficient was 0.36, when comparing 

2007 to 2008 samples to 1974 samples, and 0.37, when comparing 2007 to 2008 samples to 

1983 to 1984 samples. Similar comparisons with seine data resulted in coefficient values 

of 0.31 (for 1974) and 0.33 (for 1983 to 1984). ENSR (2008b) also compared trawl data 

throughout all river segments for 1974 and 2007 to 2008 data, which resulted in a Jaccard 

coefficient of 0.44. These results suggest low to moderate similarity of the species collected 

in 1974 and 1983 through 1984 compared to 2007 through 2008.

The results of ENSR (2008b) suggest that the current aquatic community is different and may 

be slightly more diverse than the aquatic community inhabiting the Colorado River during the 

start of operations for STP, Units 1 and 2. ENSR (2008b) observed changes in diversity near 

the RMPF as well as further downstream, which would be less likely to be impacted by STP 

operations. The increase in flow between the Colorado River and Matagorda Bay has likely

contributed to the changes in community structure and the increase in species diversity of 

aquatic species by providing passage for saltwater and estuarine species from the lower 

Colorado River to Matagorda Bay (NRC 2011b). Based on the information from the latest 

survey data and what is known about the design of the RMPF, the operation of the RMPF does 

not appear to have noticeably altered populations of the species currently found in the river.

0

5

10

15

20

25

30

35

40

Segment A Segment B Segment C

Species Richness

River Segment

1974

1983

2007-2008
Environmental Impacts of Operation

4-24

Conclusion

The NRC staff examined five lines of evidence to determine if impingement and entrainment 

have the potential to cause adverse impacts to fish and shellfish near STP. The first line of 

evidence includes impingement and entrainment studies at the RMPF during the initial filling 

and subsequent intermittent withdraw of water from the Colorado River to the MCR 

(McAden 1984, 1985). The second line of evidence includes impingement and entrainment 

studies at the CWIS from 2007 through 2008 during the withdraw of water from the MCR 

through the circulating water system (ENSR 2008a). The third line of evidence includes 

engineering designs and operational procedures to limit impingement and entrainment. The 

fourth line of evidence includes reviews by other regulatory agencies, such as EPA and the 

TCEQ. The fifth line of evidence includes survey data of fish and shellfish populations prior to 

and during operations within the Colorado River.

STPNOC conducted limited studies of impingement, entrainment, and aquatic monitoring at the 

RMPF in the lower Colorado River. However, in considering the best available information for 

the staff’s analysis, the results and conclusions of earlier impingement and entrainment studies 

and evaluations, such as McAden (1983, 1984) and NRC (1986), are likely still applicable 

because the most commonly impinged species are still common in the area near the RMPF 

(ENSR 2008b). Additionally, the design features of the RMPF that minimize losses of 

organisms would not change during the period of extended operations. In addition, EPA (1985)

has concluded that the design of the RMPF reflects best available technology for minimizing 

adverse environmental impacts. Based on the information from current and historical surveys, 

impingement and entrainment studies, and the design of the RMPF and the cooling system, 

operation of the STP cooling system does not appear to have noticeably altered populations of 

the species currently found in the river. Therefore, the NRC staff concludes that the impact from 

entrainment and impingement by the STP cooling water system on aquatic resources is SMALL.

4.5.3 Thermal Shock

For plants with cooling pond heat-dissipation systems, NRC’s GElS (1996) lists the effects of 

heat shock as an issue requiring plant-specific, Category 2, evaluation before license renewal. 

The NRC (1996) made impacts on fish and shellfish resources resulting from heat shock a 

site-specific issue because of continuing concerns about thermal discharge effects and the 

possible need to modify thermal discharges in the future in response to changing environmental 

conditions.

Information considered in this analysis includes STPNOC’s TDPES permit, modeling of the 

thermal plume, the type of cooling system (cooling pond heat-dissipation system in this case), 

and other information. To perform this evaluation, the NRC staff (a) reviewed the STPNOC’s 

ER (STPNOC 2010b), STPNOC’s TPDES permit (TCEQ 2005), and thermal plume modeling 

results (NRC 2011b) and (b) performed an audit at the STP site.

As described in Section 2.2.3, STP discharge to the Colorado River is permitted under its 

TPDES permit (TCEQ 2005). The permit allows the average daily discharge to be 144 million 

gallons per day (gpd). The TPDES permit also limits the daily average temperature to 95 °F 

and the daily maximum temperature to 97 °F. TCEQ based these limits on site-specific (or 

segment-specific) TCEQ water quality rise standards for Segment 1401, Colorado River Tidal, 

at Title 30, Chapter 307.10, Appendix A, pursuant to the Texas Administrative Code. The 

TPDES permit also prohibits discharges that would exceed 12.5 percent of the flow of the 

Colorado River at the discharge point or when the flow in the Colorado River adjacent to STP is 

less than 800 cfs. An EPA online database indicated that STP has had no CWA formal 
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enforcement actions or violations related to discharge temperature in the last 5 years 

(STPNOC 2011c). Neither EPA nor TCEQ has required STPNOC to seek a 316(a) variance or 

conduct studies in support of a 316(a) variance (STPNOC 2010b).

STPNOC operating procedures limit the blowdown flow rates and the number of discharge ports 

to be used during discharge events (STPNOC 2010b). For example, operators may open two to 

seven blowdown valves, depending on the blowdown rate (STPNOC 2010b). STPNOC 

procedures prescribe a range of allowable blowdown rates, from 80 to 308 cfs, depending on 

the Colorado River flow (STPNOC 2010b).

NRC (2011b) modeled the potential thermal plume from discharges to the Colorado River based 

on the continued operations of STP, Units 1 and 2, as well as the operation of proposed Units 3 

and 4. While this SEIS solely pertains to continued operation of STP, Units 1 and 2, the results 

of NRC’s (2011b) modeling study are presented for the following reasons:

• During operations of Units 3 and 4, discharge from all four units would mix in 

the MCR, and STPNOC would operate a single outfall to discharge water 

from the MCR (STPNOC 2010c).

• The same TPDES permit would cover Units 1 through 4 (STPNOC 2010c).

• Modeling the thermal plume based on four-unit operation bounds the 

potential impacts from continued operations of STP, Units 1 and 2.

NRC (2011b) determined that the maximum thermal plume dimensions would occur during the 

greatest difference in temperatures between the MCR water and the water in the river (20.4 °F), 

highest MCR discharge rate through seven ports (44 cfs per port, for a total of 308 cfs discharge 

rate), and the minimal flow in the Colorado River where the discharge would be equal to 

12.5 percent of the total flow in the river (2,464 cfs). NRC (2011b) modeled these conditions 

using a CORMIX (U.S. EPA computer code) mixing-zone model to determine the likely water 

temperature increases, the likely duration and frequency of discharge, and the dimensions of 

the thermal plume. The model indicated that a portion of the Colorado River would remain at 

ambient water temperature, allowing mobile aquatic organisms to avoid the thermal plume by 

passing the plume on the bottom of the river and throughout much of the water column. For 

example, during the maximum expected thermal plume dimensions, the thermal plume that is 

5 °F (2.8 °C) above ambient conditions reaches the bottom of the river from the last port of the 

discharge pipe to 120 ft (37 m) downstream, and the plume extends approximately 25 percent 

across the width of the river. In that part of the river, the benthic invertebrate species 

(e.g., grass (Palaemonetes pugio), white, and brown shrimp) would be able to move along the 

bottom of the river on the far side of the discharge structure without passing through the 

elevated temperature plume. Approximately 120 ft (37 m) downstream of the last port of the 

discharge pipe, the positive buoyancy of the warmer water causes the plume to rise to the 

surface of the river. NRC (2011b) predicted the surface of the river to have an elevated 

temperature across the entire width of the river from approximately 1,060 ft (323 m) from the 

last port of the discharge pipe to about 4,400 ft (1,341 m) downstream from the ports. As the 

plume rises to the surface and extends from bank to bank, however, a portion of the water 

column would remain at ambient river temperatures and would allow mobile organisms—such 

as foraging fish (e.g., Gulf menhaden, black drum (Pogonias cromis), spotted seatrout 

(Cynoscion nebulosus), striped mullet)—to move up and downstream.

Less mobile organisms would not be able to swim away to avoid the thermal plume, such as 

eggs, larvae, and mollusks. The most common juvenile and adult species collected in 

Segment B, where the plume could reach across the river at the surface, include Gulf 
Environmental Impacts of Operation

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menhaden, grass shrimp, black drum, white shrimp, and striped mullet (ENSR 2008b). The 

overall impact to these species from the effects of the thermal plume would be unlikely to 

noticeably alter these populations because these organisms have a high fecundity, and the 

number of organisms lost would be insignificant compared to their population in the lower 

Colorado River.

NRC’s (2011b) simulation models the discharge plume based on four-unit operations, which 

would likely be larger and occur more often than the discharge from continued operations of 

STP, Units 1 and 2. For example, STPNOC has discharged to the Colorado River once during 

the operation of STP, Units 1 and 2, in 1997, as part of a system test (STPNOC 2010b). For 

four-unit operations, STPNOC estimated that water from the MCR would be discharged to the 

Colorado River as frequently as once every 11 days and could be continuous for as much as 

75 days (NRC 2011b). NRC (2011b) determined that STPNOC’s discharge operating policy 

would rarely result in discharges from the MCR that would create a thermal plume during times 

when river water quality is poor.

The STP cooling system also limits thermal impacts to the MCR and the Colorado River. STP 

uses a cooling pond-based heat-dissipation system that withdraws and discharges cooling 

water to the MCR. The MCR is similar to a closed-cycle cooling system since the water in the 

reservoir continues to circulate from the MCR, into the plant, and back again. STP discharges 

to the Colorado River to maintain water chemistry and quality within the MCR. Because the 

water within the MCR is reused, discharges are generally less frequent than other types of 

cooling systems, such as once-through cooling systems.

After reviewing the status of STPNOC’s TPDES permit, modeling of the thermal plume, and the 

type of cooling system at STP, the NRC staff concludes that the level of thermal impacts to the 

aquatic community due to renewing the STP operating license is SMALL. The thermal plume is 

unlikely to noticeably impact aquatic resources near STP for the following reasons:

• STPNOC’s TPDES permits limit the amount and timing of discharges.

• Modeling studies indicate that mobile aquatic species could avoid the thermal 

plume by swimming at a lower depth or different side of the river.

• Species or life-stages that are less mobile organisms would not be able to 

swim away to avoid the thermal plume, such as eggs, larvae, and mollusks. 

However, most species observed in this area generally have high fecundity, 

and the number of organisms lost would be insignificant compared to their 

population in the lower Colorado River.

• Cooling water is not regularly discharged into the Colorado River since STP 

uses a cooling pond-based heat-dissipation system that reuses water from 

the MCR.

4.5.4 Mitigation

The design of the RMPF and operating procedures mitigate potential impingement, entrainment, 

and thermal shock to aquatic organisms in the lower Colorado River as follows:

• Flow Reduction—STPNOC reduces the flow rate, or amount of water 

withdrawn from the Colorado River, by reusing water in the MCR.

• Reduced Intake Velocity—At an approach velocity of 0.5 ft/s or less, most fish 

can swim away and escape from the intake current (66 FR 65274). The 
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maximum design approach velocity in front of the traveling screens at the 

RMPF is approximately 0.5 ft/s, based on a maximum pumping rate of 

approximately 538,000 gpm (STPNOC 2008, 2010c).

• Technologies to Exclude Organisms and to Collect and Return Organisms to 

the Water Body—The RMPF has coarse trash racks, traveling screens, and a 

fish bypass system (STPNOC 2010c).

• Intake Location—The RMPF is situated in a portion of the lower Colorado 

River that has lower density of many fish and invertebrates and overall lower 

species richness than further downstream, closer to the GIWW 

(ENSR 2008b).

• Time of Withdraws—Operational procedures for the RMPF also minimize 

impingement and entrainment because STPNOC intermittently draws water 

from the Colorado River for Units 1 and 2, and pumping occurs during 

periods of lower biological productivity (e.g., periods of high river flow and 

lower salinity).

Additional details regarding these mitigation measures are described above, in Section 4.5.1.

4.6 Terrestrial Resources

The issues related to terrestrial resources applicable to STP are listed in Table 4–12. The NRC 

staff did not identify any new and significant information during the review of STPNOC’s ER, the 

staff’s site audit, the scoping process, or the evaluation of other available information (e.g., 

applicable permits and data reports as listed in the reference section of this SEIS chapter). 

Therefore, there is no impact related to these issues beyond those discussed in the GEIS. For 

these issues and consistent with the GEIS, the NRC staff concludes that the impacts to 

terrestrial resources are SMALL. 

Table 4–12. Terrestrial Resources Issues Identified in the GEIS

Issue GEIS Section Category

Cooling tower impacts on crops & ornamental vegetation 4.3.4 1

Cooling town impacts on native plants 4.3.5.1 1

Bird collisions with cooling towers 4.3.5.2 1

Powerline ROW management (cutting herbicide application) 4.5.6.1 1

Bird collisions with powerlines 4.5.6.1 1

Impacts of electromagnetic fields on flora & fauna (plants, agricultural 

crops, honeybees, wildlife, livestock) 4.5.6.3 1 

Floodplains & wetland on powerline ROW 4.5.7 1

Source: Table B–1 in Appendix B, Subpart A, to 10 CFR Part 51
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4.7 Protected Species and Habitats

Section 2.2.7 of this SEIS describes protected species and habitats in the vicinity of the STP 

site. Table 4–13 lists the one Category 2 issue related to protected species and habitats that is 

applicable to STP.

Table 4–13. Protected Species Issues Identified in the GEIS

Issue GEIS Section Category

Threatened or endangered species 4.1 2

Source: Table B–1 in Appendix B, Subpart A, to 10 CFR Part 51

This site-specific, or Category 2 issue, requires consultation with the appropriate agencies to 

determine whether threatened or endangered species are present and whether they would be 

adversely affected by continued operation of STP during the license renewal term. In the case 

of STP, the U.S. Fish and Wildlife Service (FWS) is responsible for terrestrial and freshwater 

species listed under the Endangered Species Act (ESA), the Bald and Golden Eagles Act, and 

the Migratory Bird Treaty Act (MBTA). The National Marine Fisheries Service (NMFS) is 

responsible for marine and anadromous species listed under the ESA and the 

Magnuson–Stevens Fishery Conservation and Management Act (MSA) and those species that 

have been designated as NMFS Species of Concern. The Texas Parks and Wildlife Division is 

responsible for species protected by the State of Texas Statutes. Descriptions of protected 

species and habitats appear in Section 2.2.8. In its assessment, the NRC defined the action 

area in Section 2.2.8. 

4.7.1 Species and Habitats Protected Under the Endangered Species Act

Chronology of Endangered Species Act Section 7 Consultation 

The NRC staff corresponded with both the FWS and NMFS to determine impacts to Federally 

listed species and to decide whether to initiate Section 7 consultation as a result of the 

proposed STP license renewal. The NRC developed a list of Federally listed species within the 

vicinity of STP and requested concurrence on this list in a February 16, 2011, letter 

(NRC 2011f). The FWS responded to this request on June 2, 2011, with an updated list and 

recommendations concerning specific species (FWS 2011b). Specific species for which FWS 

had concerns are discussed in Section 2.2.8.1.

The NRC sent a similar letter to the NMFS on February 16, 2011 (NRC 2011h). The NMFS 

responded to this letter in an e-mail dated March 3, 2011 (NMFS 2011c) and provided the NRC 

with a list of Federally listed species under its jurisdiction in Texas. Following the issuance of 

the draft SEIS, the NRC sent letters to the FWS and NMFS on December 10, 2012 

(NRC 2012c, 2012d), requesting concurrence with the staff’s effect determinations for Federally 

listed species in accordance with 50 CFR 402(j).

For species under NMFS’s jurisdiction, the NRC staff concluded that there would be no effect on 

these species (see below). Per an e-mail dated January 29, 2013 (NMFS 2013), NMFS does 

not typically concur or not concur with “no effect” determinations by the staff. Thus, for species 

under NMFS’s jurisdiction, no further consultation is required, and the NRC has fulfilled its 

obligations under Section 7 of the ESA for species under NMFS’s jurisdiction.
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For species under FWS’s jurisdiction, the FWS Clear Lake Ecological Services Office contacted 

the NRC, by phone on January 31, 2013, to discuss NRC’s letter and to request additional maps 

of the transmission lines from the NRC. The NRC provided the requested information via e-mail 

later that day (NRC 2013a). On February 5, 2013, the FWS Clear Lake Ecological Services 

Office and the NRC spoke again by phone, and the FWS Clear Lake Ecological Services 

Offices noted that it was preparing additional information requests that it would send the NRC. 

These requests were sent in an e-mail dated March 14, 2013 (FWS 2013d). The NRC has 

updated its protected species analysis in this SEIS as a result of the information provided in 

FWS’s March 14, 2013, e-mail. Informal Section 7 consultation with the FWS continues at this 

time.

Species and Habitats Under NMFS Jurisdiction 

Section 2.2.8 discusses species and habitats protected under the ESA and within NMFS’s 

jurisdiction that occur in Matagorda County and have the potential to occur in the action area (as 

defined in Section 2.2.8). The NRC staff identified seven listed species. However, the staff 

determined that none of these species occur within the action area. Therefore, the NRC 

concludes that the proposed STP license renewal would have no effect on these species (see

Table 4–14). 

The NRC staff did not identify any candidate or proposed species or proposed or designated 

critical habitat under NMFS’s jurisdiction within the action area. Thus, the proposed STP 

license renewal would have no effect on any candidate or proposed species or proposed or 

designated critical habitat under NMFS’s jurisdiction.

Table 4–14. ESA Effect Determinations for Federally Listed Species

Under NMFS Jurisdiction

Species

ESA Effect 

Determination

Justification for Determination

Fish

smalltooth sawfish

(Pristis pectinata) no effect The species does not occur in the action area.

Mammals

West Indian manatee

(Trichechus manatus) no effect The species does not occur in the action area.

Reptiles

loggerhead sea turtle

(Caretta caretta) no effect The species does not occur in the action area.

green sea turtle

(Chelonia mydas) no effect The species does not occur in the action area.

leatherback sea turtle

(Dermochelys coriacea) no effect The species does not occur in the action area.

hawksbill sea turtle

(Eretmochelys imbricata) no effect The species does not occur in the action area.

Kemp’s ridley sea turtle

(Lepidochelys kempii) no effect The species does not occur in the action area.
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Species and Habitats Under FWS Jurisdiction

Section 2.2.8 discusses species and habitats protected under the ESA and within FWS’s 

jurisdiction that occur in Matagorda County and have the potential to occur in the action area. 

The NRC staff identified 11 listed species, of which the staff determined that 8 do not occur in 

the action area and, thus, would not be affected by the proposed STP license renewal. The 

remaining three species are discussed below in more detail. Table 4–14a summarizes the NRC 

staff’s effect determinations for listed and candidate species.

Table 4–14a. ESA Effect Determinations for Federally Listed and Candidate Species

Under NMFS’s Jurisdiction

Species ESA Effect 

Determination Justification for Determination

Birds

Sprague’s pipit

(Anthus spragueii) 

may affect, but is 

not likely to 

adversely affect

The species may occur in the action 

area. However, the proposed action 

would not affect habitat use, prey 

availability, or breeding or nesting 

behavior.

piping plover

(Charadrius melodus) no effect The species does not occur in the action area.

northern aplomado falcon

(Falco femoralis 

septentrionalis) 

may affect, but is 

not likely to 

adversely affect

The species may occur in the action 

area. However, the proposed action 

would not affect habitat use, prey 

availability, or breeding or nesting 

behavior.

whooping crane

(Grus americana) no effect The species does not occur in the action area.

eskimo curlew

(Numenius borealis) no effect The species does not occur in the action area.

Mammals

red wolf

(Canis rufus) no effect The species does not occur in the action area.

ocelot

(Leopardus pardalis) no effect The species does not occur in the action area.

Louisiana black bear

(Ursus americanus luteolus) no effect The species does not occur in the action area.

Mollusks

smooth pimpleback

(Quadrula houstonensis) no effect The species does not occur in the action area.

Texas fawnsfoot

(Truncilla macrodon) no effect The species does not occur in the action area.
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Species ESA Effect 

Determination Justification for Determination

Reptiles

American alligator

(Alligator mississipiensis) not applicable

The species is known to occur in the 

action area. It is listed as threatened 

only because its appearance is similar to 

another species; therefore, it is not 

subject to Section 7 consultation.

The STP site is in close proximity to four units of designated piping plover (Charadrius melodus) 

critical habitat, the closest of which lies 7 mi (11 km) south of the STP site boundary along the 

shoreline of West Matagorda Bay. Because continued operation and maintenance of the STP 

site would involve no onsite or offsite disturbances, the proposed license renewal would result in 

no direct or indirect effects to piping plover critical habitat. Thus, the NRC staff concludes that 

the proposed license renewal would have no effect on designated piping plover critical habitat. 

The NRC staff did not identify any proposed critical habitat during its review.

The NRC staff did not identify any Federally proposed species or proposed critical habitat within 

the action area during its review. Additionally, in its correspondence with NRC, the FWS did not 

identify any proposed species or proposed critical habitat. Thus, the NRC staff concludes that 

the proposed license renewal would have no effect on Federally proposed species or proposed 

critical habitat.

Sprague’s Pipit (Anthus spragueii). The Sprague’s pipit may occur in areas of suitable habitat, 

such as mixed grasslands and pastureland, within the action area. If Sprague’s pipit occupies 

any habitat within the action area, the NRC staff assumes that the species would continue to 

occupy the area as during the current operating license term. Continued operation and 

maintenance of the STP site during the proposed license renewal term will not involve any 

construction, ground-disturbing activities, or changes to existing land use conditions in either 

natural or developed areas. Thus, continued operation of STP would not affect habitat or prey 

availability. Noise levels and human activity would remain similar to current operations and 

would not cause any additional disturbances that would cause pipits to avoid or abandon habitat 

within the action area. The Sprague’s pipit winters in Texas, so the proposed license renewal 

would not affect breeding or young-rearing. The NRC staff did not identify any direct or indirect 

adverse effects to the Sprague’s pipit that would result from continued operation during the 

proposed license renewal term. Furthermore, the continued operation of STP during the 

proposed license renewal term would preserve the existing habitats on the STP site. Therefore, 

this could result in beneficial effects to the species.

Though the Sprague’s pipit may occur in the action area, the NRC staff has not identified any 

records or studies to date that confirm that the Sprague’s pipit inhabits the action area, and it 

has not found any information that indicates that adverse effects to the species would occur as 

a result of the proposed license renewal term. However, if the species was observed on the 

STP site, the NRC has measures in place to ensure that it would be notified so that the NRC 

staff could determine the appropriate course of action, such as possibly reinitiating Section 7 

consultation under the ESA with the FWS at that time. STP’s operating license, Appendix B, 

“Environmental Protection Plan,” Section 4.1 (NRC 1988, 1989) requires STPNOC to report to 

the NRC within 24 hours any occurrence of a species protected by the ESA on the STP site. 

Additionally, the NRC’s regulations containing notification requirements require that operating 

nuclear power reactors report to the NRC within 4 hours “any event or situation, related 
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to...protection of the environment, for which a news release is planned or notification to other 

government agencies has been or will be made” (10 CFR 50.72(b)(2)(xi)). Such notifications 

include reports regarding Federally listed species, as described in Section 3.2.12 of 

NUREG-1022, “Event Reporting Guidelines for 10 CFR 50.72 and 50.73” (NRC 2013b).

The NRC staff concludes that the proposed license renewal may affect, but is not likely to 

adversely affect, the Sprague’s pipit.

Northern Aplomado Falcon (Falco femoralis septentrionalis). The northern aplomado falcon 

may occur in areas of suitable habitat, such as scrub shrub, mixed grasslands, and pastureland, 

within the action area. If northern aplomado falcons occupy any habitat within the action area, 

the NRC staff assumes that the species would continue to occupy the area as during the current 

operating license term. Continued operation and maintenance of the STP site during the 

proposed license renewal term will not involve any construction, ground-disturbing activities or 

changes to existing land use conditions in either natural or developed areas. Thus, continued 

operation of STP would not affect habitat or prey availability. Noise levels and human activity 

would remain similar to current operations and would not cause any additional disturbances that 

would cause individuals to avoid or abandon habitat within the action area. In its Federal 

Register notice documenting the establishment of an experimental population of northern 

aplomado falcons in New Mexico and Arizona, the FWS noted that the species appears to be 

relatively tolerant of human presence (71 FR 42298). Nesting pairs have been observed to 

tolerate approach within 100 m (328 ft) of their nests by researchers, have nested within 100 m 

(328 ft) of highways in eastern Mexico, and are frequently found nesting in association with 

managed livestock pastureland in Mexico and Texas (71 FR 42298).

The NRC staff did not identify any direct or indirect adverse effects to the northern aplomado 

falcon that would result from continued operation during the proposed license renewal term. 

Furthermore, the continued operation of STP during the proposed license renewal term would 

preserve the existing habitats on the STP site. Therefore, this could result in beneficial effects 

to the species.

Though the northern aplomado falcon may occur in the action area, the NRC staff has not 

identified any records or studies to date that confirm that the species inhabits the action area, 

and it has not found any information that indicates that adverse effects to the species would 

occur as a result of the proposed license renewal term. 

The NRC staff concludes that the proposed license renewal may affect, but is not likely to 

adversely affect, the northern aplomado falcon.

American Alligator (Alligator mississipiensis). American alligators inhabit Kelly Lake, Little 

Robins Slough, site wetlands, and the various dikes associated with the MCR. Continued 

operation and maintenance of the STP site during the proposed license renewal term will not 

involve any construction, ground-disturbing activities, or changes to existing land use conditions 

in either natural or developed areas. Water use and quality would also not change significantly 

during the proposed license renewal term. Therefore, the proposed license renewal would not 

affect habitat or prey availability or create any changes that would alter the behavior of alligators 

on the site. However, the American alligator is threatened due to similarity of appearance with 

the American crocodile (Crocodylus acutus), which does not occur in the action area. The 

American alligator is not biologically endangered or threatened and is not subject to Section 7 

consultation (FWS 2012), so an ESA affect determination does not apply to this species.
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4.7.2 Species Designated as NMFS Species of Concern 

Though some of the species of concern listed in Section 2.2.8.2 occur in Matagorda Bay, none 

of the species of concern in the vicinity of STP occur in the Colorado River and would, therefore, 

not be impinged or entrained by STP cooling water intake or otherwise affected by the proposed

license renewal. The NRC staff concludes that there is no adverse impact to any NMFS 

species of concern.

4.7.3 Species Protected Under the Bald and Golden Eagles Protection Act

Though bald eagles occur throughout the STP region, no known nests are in close proximity to 

any of the STP buildings, parking lots, or other structures that could be disturbed by ongoing 

human activity. Because the proposed license renewal does not involve construction or land 

disturbances, no bald eagle habitat would be affected by the proposed license renewal. The 

NRC staff concludes that there is no adverse impact to the bald eagle.

4.7.4 Species Protected Under the Migratory Bird Treaty Act

As discussed in Section 2.2.8.4, a variety of migratory birds inhabit the STP site and 

surrounding region. Because the proposed license renewal does not involve construction or 

land disturbances, no migratory birds would be affected by the proposed license renewal. The 

NRC staff concludes that there is no adverse impact to migratory birds.

4.7.5 Species Protected Under the Marine Mammal Protection Act

Section 2.2.8.5 discusses marine mammals in the vicinity of STP. None of these species occur 

in the Colorado River and would, therefore, not be impinged or entrained by STP cooling water 

intake or otherwise affected by the proposed license renewal. The NRC staff concludes that 

there is no adverse impact to any marine mammals.

4.7.6 Species Protected Under the Magnuson–Stevens Act

Section 2.2.8.6 identifies species with EFH with the potential to occur in the vicinity of STP. Of 

these species, ENSR (2008) collected the mangrove snapper and brown shrimp, white shrimp 

have been collected during ecological studies associated with STP, and white and brown shrimp 

have been collected during impingement or entrainment samples.

The NRC prepared an EFH assessment (NRC 2011c) as part of the review of the Units 3 and 4 

COL application review. The NRC staff included the Colorado River, Matagorda Bay, and the 

Gulf of Mexico in the scope of its analysis because construction activities for the proposed 

Units 3 and 4 would include barge traffic. In that EFH assessment, the NRC concluded that the 

proposed Units 3 and 4 would have minimal adverse effects on EFH. The NMFS concurred 

with this determination in April 2010 (NMFS 2010). Because the area that would be affected by 

the proposed license renewal is smaller than the affected area for the proposed STP, Units 3 

and 4, and would not require any construction or changes to current operation, the NRC staff 

concludes that the NRC’s EFH assessment for the proposed STP, Units 3 and 4 (NRC 2011c), 

bounds the analysis for the proposed license renewal of STP, and that there are no adverse 

impacts to any EFH species.

Following the issuance of the draft SEIS, the NRC forwarded a copy of the draft SEIS to NMFS 

and requested EFH consultation per 50 CFR 600.920 in a letter dated December 11, 2012 

(NRC 2012b). The NRC followed up with this request via e-mail on February 25, 2013 
Environmental Impacts of Operation

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(NRC 2013c). By e-mail dated March 1, 2013, NMFS stated that it concurs with NRC’s 

conclusion that the continued operation of STP would not adversely affect EFH. NMFS also 

confirmed that no further EFH consultation is required for the proposed STP license renewal 

(NMFS 2013b). 

4.7.7 Species Protected Under State of Texas Statutes

Section 2.2.8.7 discusses species protected under Texas’s State Statutes. Some State-listed 

species may occur along the transmission line corridors. However, the minimal transmission 

line maintenance associated with the STP transmission lines is unlikely to affect any State-listed 

species. Because the transmission line corridors are well-established, continued maintenance 

will also not reduce or affect the amount or quality of available habitat. The NRC staff 

concludes that there are no adverse impacts to any State-listed species.

4.7.8 Conclusion

The conclusions for species and habitat protected by each Act are stated above in terms 

appropriate to those Acts. 

4.8 Human Health

The human health issues applicable to STP are discussed below and listed in Table 4–15 for 

Category 1, Category 2, and uncategorized issues.

Table 4–15. Human Health Issues. 

Table B-1 of Appendix B to Subpart A of 10 CFR Part 51 contains more information on these 

issues.

Issue GEIS Section Category

Radiation exposures to the public during refurbishment 3.8.1(a) 1

Occupational radiation exposures during refurbishment 3.8.2(a)

1 

Microbiological organisms (occupational health) 4.3.6 1 

Microbiological organisms (public health, for plants using lakes or 

canals or cooling towers or cooling ponds that discharge to a small 

river)

4.3.6 2 

Noise 4.3.7 1 

Radiation exposures to public (license renewal term) 4.6.2 1 

Occupation radiation exposures (license renewal term) 4.6.3 1 

Electromagnetic fields—acute effects (electric shock) 4.5.4.1 2 

Electromagnetic fields—chronic effects 4.5.4.2 Uncategorized
Environmental Impacts of Operation

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Issue GEIS Section Category

(a) Issues apply to refurbishment, an activity that STP does not plan to undertake.

Source: Table B–1 in Appendix B, Subpart A, to 10 CFR Part 51

4.8.1 Generic Human Health Issues

Category 1 issues applicable to STP in regard to human health impacts are listed in Table 4–15. 

STPNOC stated in its ER that it was not aware of any new and significant human health issues 

associated with the renewal of the STP operating license. The staff has not identified any new 

and significant information related to human health issues associated with the operation of STP, 

Units 1 and 2, during the period of license renewal as a result of its independent review of 

STPNOC’s ER, the site audit, and the scoping process. The NRC staff also reviewed other 

sources of information, such as data reports, as listed in the reference section of this SEIS

chapter. Therefore, the NRC staff concludes that, for Category 1 human health issues, there 

would be no impact from nonradiological issues to the public or to workers during the renewal 

term beyond those discussed in the GEIS.

4.8.2 Radiological Impacts of Normal Operations

Category 1 issues applicable to STP in regard to radiological impacts are listed in Table 4–15. 

Regarding the potential for new and significant radiological information, STPNOC evaluated the 

issue of tritium contained in groundwater on the plant site and concluded that the tritium in 

groundwater would not preclude the water’s current or future use; therefore, the issue is not new 

and significant. The staff discusses groundwater monitoring for radioactivity in Sections 2.2.5.2

and 4.4.3 and later in this section. In its radiological evaluation, the NRC staff determined that 

the issue is not new and significant.

The staff has not identified any new and significant information related to human health issues 

associated with radiation exposures during its independent review of STPNOC’s ER, the site 

audit, and the scoping process. Therefore, the NRC staff concludes that there would be no 

impact from radiation exposures to the public or to workers during the renewal term beyond 

those discussed in the GEIS. 

The findings in the GEIS are as follows:

• Radiation exposures to public (license renewal term)—Based on information 

in the GEIS, the NRC found that radiation doses to the public will continue at 

current levels associated with normal operations.

• Occupational exposures (license renewal term)—Based on information in the 

GEIS, the NRC found that projected maximum occupational doses during the 

license renewal term are within the range of doses experienced during 

normal operations and normal maintenance outages and would be well below 

regulatory limits.

According to the GEIS, the impacts to human health are SMALL, and additional plant-specific 

mitigation measures are unlikely to be sufficiently beneficial to warrant implementation. There 

are no Category 2 issues related to radiological impacts of routine operations.

The information presented below is a discussion of selected radiological programs conducted at 

STP. 
Environmental Impacts of Operation

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South Texas Project Radiological Environmental Monitoring Program. STP conducts a 

Radiological Environmental Monitoring Program (REMP) to assess the radiological impact, if 

any, to its employees, the public, and the environment from the operations at STP, Units 1 

and 2. The REMP measures the aquatic, terrestrial, and atmospheric environment for 

radioactivity, as well as the ambient radiation. In addition, the REMP measures background 

radiation (i.e., cosmic sources, global fallout, and naturally occurring radioactive material, 

including radon). The REMP supplements the radioactive effluent monitoring program by 

verifying that any measurable concentrations of radioactive materials and levels of radiation in 

the environment are not higher than those calculated using the radioactive effluent release 

measurements and transport models.

An annual radiological environmental operating report is issued, which contains a discussion of 

the results of the monitoring program. The report contains data on the monitoring performed for 

the most recent year. The REMP collects samples of environmental media to measure the 

radioactivity levels that may be present. The media samples are representative of the radiation 

exposure pathways that may impact the public.

The STP REMP is made up of four categories based on the exposure pathways to the public—

airborne, waterborne, ingestion, and direct radiation. The air is sampled in areas around STP 

by measuring the levels of radioactive iodine and particulate matter on filters. For the 

waterborne pathway, the water samples are taken from surface water, groundwater, and 

drinking water. Also included in this pathway are sediment samples taken from the MCR and 

the Colorado River. The ingestion pathway samples local broadleaf vegetation, agricultural 

products, and food products. The direct exposure pathway measures environmental radiation 

doses using thermoluminescent dosimeters.

In addition to the REMP, STP has an onsite Groundwater Protection Program designed to 

monitor the onsite plant environment for detection of leaks from plant systems and pipes 

containing radioactive liquid (STPNOC 2010b). Additional information on the Groundwater 

Protection Program is contained later in this section and in the Groundwater Quality section in 

Chapter 2 (Section 2.2.5.2) of this document.

The staff reviewed the STP annual radiological environmental operating reports for 2006 

through 2010 to look for any significant impacts to the environment or any unusual trends in the 

data (STPNOC 2007a, 2008d, 2009a, 2010a, 2011a). A 5-year period provides a data set that 

covers a broad range of activities that occur at a nuclear power plant such as refueling outages, 

non-refueling outage years, routine operation, and years where there may be significant 

maintenance activities. In addition, data from the applicant’s current 2012 REMP report was 

reviewed and added to this final SEIS (STPNOC 2013a, 2013b). Based on the staff’s review, 

no adverse trends (i.e., steadily increasing buildup of radioactivity levels) were observed, and 

the data showed that there was no measurable impact to the environment from operations at 

STP. 

Tritium Groundwater Monitoring. Nuclear industry events involving tritium prompted STP to 

sample groundwater in the shallow aquifer near the nuclear plants in 2005.

In 2007, the NEI established a standard for monitoring and reporting radioactive isotopes in 

groundwater. This standard is contained in NEI 07-07, Industry Ground Water Protection 

Initiative—Final Guidance Document (NEI 2007). STPNOC implemented the recommendations 

of this industry standard and has broadened the Groundwater Monitoring Program to include 

samples collected near the nuclear plants. Results of STPNOC’s Groundwater Monitoring 

Program are contained in the annual REMP report submitted to the NRC in May of each year. 
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These reports are available for review by the public through the Agencywide Documents Access 

and Management System (ADAMS) electronic reading room available through the NRC Web 

site.

In the 2010 REMP report, STPNOC reported that tritium was detected on site. The applicant’s 

evaluation shows that the positive results are likely due to the well’s location in an area that is 

influenced by the MCR. Other positive samples appear to be the result of discharges to the 

ground involving water previously considered non-radioactive since only trace quantities of 

tritium were measured. All groundwater sample containing tritium were below the EPA’s DWS

of 20,000 pCi/l (740 Becquerels per liter). Also, the data showed no impact to sources of 

drinking water. The water samples from the onsite drinking water source (a deep aquifer) and 

offsite sampling of the Colorado River showed only natural background radiation levels 

(STPNOC 2011a). The 2012 REMP report showed that tritium levels were generally stable in 

2012 and remained below the EPA’s DWS. 

Based on its review of the applicant’s monitoring reports, including the 2012 data, the staff 

concludes that there are no significant impacts to human health associated with tritium in the 

groundwater at the STP site. The applicant’s Groundwater Protection Program will monitor the 

groundwater and report the results in its annual radiological environmental monitoring report. 

Also, NRC inspectors will periodically review STPNOC’s Groundwater Protection Program to 

ensure the program continues to be effective. 

Texas Department of State Health Services Environmental Monitoring Program. The Texas 

Department of State Health Services (DSHS) performs its own independent environmental 

monitoring around the STP site and other nuclear facilities (i.e., research reactors, commercial 

users of radioactive material, and the U.S. Department of Energy’s (DOE’s) Pantex facility) 

located in Texas. All analyses of environmental media (i.e., soil, air, water, and vegetation) are 

performed by its Laboratory Services Section. The State’s radiation branch performs the 

monitoring of direct radiation from a facility using TLDs.

The staff reviewed the State’s environmental summary reports for 2005 through 2009 (the most 

recent report available at the time of the staff’s review) (TDSHS 2012). In each of the reports, 

the State concluded that the sample data indicated no release of radioactive material to the 

environment that exceeded the regulatory or license limits of the DSHS or any other agency 

such as the NRC or the DOE. For this final SEIS, the staff searched for a more current report 

than the 2009 report reviewed in the draft SEIS and did not find a more current report.

South Texas Project Radioactive Effluent Release Program. All nuclear plants were licensed 

with the expectation that they would release radioactive material to both the air and water during 

normal operation. However, NRC regulations require that radioactive gaseous and liquid 

releases from nuclear power plants must meet radiation dose-based limits specified in 

10 CFR Part 20 and the as low as is reasonably achievable (ALARA) criteria in Appendix I to 

10 CFR Part 50. Regulatory limits are placed on the radiation dose that members of the public 

can receive from radioactive effluents released by a nuclear power plant. In addition, nuclear 

power plants are required by 10 CFR 50.36(a) to submit an annual report to the NRC, which 

lists the types and quantities of radioactive effluents released into the environment. The 

radioactive effluent release reports are available for review by the public through the ADAMS 

electronic reading room available through the NRC Web site.

The NRC staff reviewed the annual radioactive effluent release reports for 2006 through 2010 

(STPNOC 2007b, 2008e, 2009b, 2010d, 2011d). In addition, data from the applicant’s current 

2012 radioactive effluent release report were reviewed and included in this final SEIS 

(STPNOC 2013a, 2013b). The NRC staff’s review focused on the calculated doses to a 
Environmental Impacts of Operation

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member of the public from radioactive effluents released from STP. The doses were compared 

to the radiation protection standards in 10 CFR 20.1301 and the ALARA dose design objectives 

in Appendix I to 10 CFR Part 50.

Dose estimates for members of the public are calculated based on radioactive gaseous and 

liquid effluent release data and atmospheric and aquatic transport models. The 2012 annual 

radioactive material release report (STPNOC 2013a, 2013b) contains a detailed presentation of 

the radioactive discharges and the resultant calculated doses. The following summarizes the 

calculated dose to a member of the public located outside the STP site boundary from 

radioactive gaseous and liquid effluents released during 2012: 

• The total-body dose to an offsite member of the public from STP Unit 1 

radioactive liquid effluents was 9.25x10-3 mrem (9.25x10-5 mSv) and 

4.48x10-4 mrem (4.48x10-6 mSv) for Unit 2, which is well below the 3 mrem 

(0.03 mSv) dose criterion in Appendix I to 10 CFR Part 50.

• The organ (liver) dose to an offsite member of the public from STP Unit 1 

radioactive liquid effluents was 9.28x10-3 mrem (9.28x10-5 mSv) and 

4.52x10-4 mrem (4.52x10-6 mSv), which is well below the 10 mrem 

(0.10 mSv) dose criterion in Appendix I to 10 CFR Part 50.

• The air dose at the site boundary from gamma radiation in gaseous effluents 

from STP Unit 1 was 1.89x10-3 mrad (1.89x10-5 mGy) and 4.93x10-4 mrad 

(4.93x10-6 mGy) for Unit 2, which is well below the 10 mrad (0.1 mGy) dose 

criterion in Appendix I to 10 CFR Part 50.

• The air dose at the site boundary from beta radiation in gaseous effluents 

from Unit 1 was 6.99x10-4 mrad (6.99x10-6 mGy) and 2.28x10-4 mrad 

(2.28x10-6 mGy) for Unit 2, which is well below the 20 mrad (0.2 mGy) dose 

criterion in Appendix I to 10 CFR Part 50.

• The dose to an organ (bone) from radioactive iodine, radioactive particulates, 

and carbon-14 from Unit 1 was 3.29x10-1 mrem (3.29x10-3 mSv) and 

3.28x10-1 mrem (3.28x10-3 mSv) for Unit 2, which is well below the 15 mrem 

(0.15 mSv) dose criterion in Appendix I to 10 CFR Part 50.

The highest dose from direct radiation to an offsite member of the public was 

7.0x10-3mrem (7.0x10-5 mSv). This dose is based on a conservative 

assumption that an individual is located at the STP site fence east of the two 

reactor units for the entire year.

• The total-body dose from radioactive gaseous and liquid effluents combined 

with the dose from direct radiation from STP, Units 1 and 2, equals the 

maximum dose from all pathways to an offsite member of the public. The 

total annual dose is 2.3x10-2 mrem (2.3x10-4 mSv), which is well below the 

25 mrem (0.25 mSv) dose standard in EPA’s 40 CFR Part 190.

The staff’s review of the STP Radioactive Effluent Control Program showed that radiation doses 

to members of the public were controlled within Federal radiation protection standards 

contained in Appendix I to 10 CFR Part 50, 10 CFR Part 20, and 40 CFR Part 190.

The applicant has no plans to conduct refurbishment activities during the license renewal term; 

however, routine plant refueling and maintenance activities currently performed will continue 

during the license renewal term. Based on the past performance of the radioactive waste 

system to maintain the dose from radioactive effluents to be ALARA, similar performance is 
Environmental Impacts of Operation

4-39

expected during the license renewal term. Continued compliance with regulatory requirements 

is expected during the license renewal term; therefore, the impacts from radioactive effluents 

would be SMALL.

4.8.3 Microbiological Organisms

For power plants that use a cooling pond, lake, or canal or that discharge to a small river, the 

effects of microbiological organisms on human health are listed as a Category 2 issue and 

require plant-specific evaluation for license renewal review. This issue is applicable to STP 

because the facility uses a cooling pond, as defined in the GElS (NRC 1996). The cooling pond 

(MCR) discharges to Colorado River that has the mean annual average flow of approximately 

2,629 cfs (NRC 2011b). This meets the definition of a small river. The MCR is within the 

confine of the STP security perimeter and is not available for public use.

The Category 2 designation is based on the potential for public health impacts associated with 

thermal enhancement of Naegleria fowleri, a pathogenic amoeba, and other enteric pathogens 

that could not be assessed generically. The NRC noted that impacts of nuclear plant thermal 

discharges are considered to be of small significance if they do not enhance the presence of 

microorganisms that are detrimental to water quality and public health (NRC 1996).

Microbiological organisms that grow at temperatures above 45 °C to 50 °C (113 °F to 122 °F) 

are termed thermophilic, or heat-loving, organisms (Brock 1974). STP has TPDES permit 

(No. WQ0001908000) to discharge to the Colorado at the daily average temperature limit of 

95 °F and daily maximum temperature limit of 97 °F (STPNOC 2010). These limits are below 

the temperature at which thermophilic microorganisms grow and thrive (113 °F to 122 °F). 

Hence, the potential of waterborne disease outbreak due to discharge from the MCR to the 

Colorado River is remote.

Furthermore, the TPDES permit limits the discharge to less than 12.5 percent of the river flow 

and may not exceed 200 million gpd. It is likely that the discharge would occur during high river 

flow periods, which are reported by the STPNOC to be during the winter and spring when the 

river temperature is at low level.

The staff asked the Texas Department of Health about any concerns the department might have 

relative to the microorganisms in the MCR that could cause waterborne disease outbreak in the 

area (NRC 2012a). The department responded that it did not have any records of such 

outbreak, and it is not aware of any potential concerns about outbreaks associated with the 

operation of STP during the extended period of operation.

The staff concludes that the potential impacts to public health from microbiological organisms, 

resulting from operation of the STP cooling water discharge system to the aquatic environment 

on or near the site, are SMALL, and no further mitigations are warranted.

4.8.4 Electromagnetic Fields—Acute Effects

Based on the GEIS, the NRC found that electric shock resulting from direct access to energized 

conductors or from induced charges in metallic structures has not been found to be a problem at 

most operating plants and, generally, is not expected to be a problem during the license renewal 

term. However, site-specific review is required to determine the significance of the electric 

shock potential along the portions of the transmission lines that are within the scope of this 

SEIS. 
Environmental Impacts of Operation

4-40

In the GEIS (NRC 1996), the NRC found that without a review of the conformance of each 

nuclear plant transmission line with National Electrical Safety Code (NESC) criteria, it was not 

possible to determine the significance of the electric shock potential (IEEE 2002). Evaluation of 

individual plant transmission lines is necessary because the issue of electric shock safety was 

not addressed in the licensing process for some plants. For other plants, land use in the vicinity 

of transmission lines may have changed, or power distribution companies may have chosen to 

upgrade line voltage. To comply with 10 CFR 51.53(c)(3)(ii)(H), the applicant must provide an 

assessment of the impact of the proposed action on the potential shock hazard from the 

transmission lines if the transmission lines that were constructed for the specific purpose of 

connecting the plant to the transmission system do not meet the recommendations of the NESC 

for preventing electric shock from induced currents. The NRC uses the NESC criteria as its 

baseline to assess the potential human health impact of the induced current from an applicant’s 

transmission lines. As discussed in the GEIS, the issue of electric shock is of small significance 

for transmission lines that are operated in adherence with the NESC criteria.

STPNOC analyzed its transmission lines to identify the limiting case for each line where the 

potential exists for the highest current-induced shock. STPNOC calculated the electric field 

strength and induced current for each of the lines using a computer code called ACDCLINE, 

produced by the Electric Power Research Institute. The input parameters included the design 

features of each of the limiting-case transmission lines, and a tractor-trailer was assumed to be 

the maximum vehicle size under the lines. STPNOC reported in its ER and in two supplemental 

letters (STPNOC 2011c, 2011f) that there are three transmission lines (i.e., two Hill County lines 

and one Skyline line) that exceed the NESC 5 milliampere (mA) criterion for preventing electric 

shock from induced currents. However, STPNOC states that the configuration of these lines 

has changed since the original plant construction. These lines are no longer directly connected 

with STP. A substation was constructed at Elm Creek. The original Hill County and Skyline 

transmission lines are now looped into the Elm Creek substation before proceeding to the Hill 

County and Skyline substations. The lines pass through land that is primarily agricultural and 

rangeland, with some forest land and lesser land-use categories. The areas are mostly remote, 

with low population densities. The lines cross numerous county, State, and U.S. highways.

As reported by STPNOC in its ER, the service providers for the STP transmission lines have 

surveillance and maintenance procedures that periodically examine the lines to ensure they 

remain within their design criteria. These procedures include routine aerial inspections that 

include checks for encroachments, broken conductors, broken or leaning structures, and signs 

of trees burning, any of which would be evidence of clearance problems. Ground inspections 

include examination for clearance, integrity of structures, and surveillance for dead or diseased 

trees that might fall on the transmission lines. Problems noted during any inspection are 

reported for follow-up corrective action. STPNOC has considered potential mitigation measures 

to reduce or avoid adverse impacts from electric shock from its transmission lines, with a 

combination of options, as follows:

• re-examining the induced current calculations for selected transmission lines 

(for accuracy and possible safety margin identification),

• raising the transmission towers at the potentially affected road-transmission 

line intersections,

• modifying the double-circuit lines to reduce the current-induced shock 

potential, or

• placing caution signs under the transmission lines.
Environmental Impacts of Operation

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Based on information provided by STPNOC and potential mitigation measures (to reduce or 

avoid adverse impacts) considered by the applicant, the staff concludes that potential impact 

from acute electric shock during the renewal period would be SMALL to MODERATE. This 

conclusion is based on the fact that the three transmission lines exceed the NESC 5 mA 

criterion by a small percentage, the locations where the lines exceed the standard are in remote 

locations or are on private property, and the applicant, in accordance with 

10 CFR 51.53(c)(3)(iii), has considered potential mitigation measures to reduce or avoid 

adverse impacts from electric shock.

4.8.5 Electromagnetic Fields—Chronic Effects

In the GEIS, the effects of chronic exposure to 60 Hz electromagnetic fields from powerlines 

were not designated as Category 1 or 2 and will remain uncategorized until a scientific 

consensus is reached on the health implications of these fields.

The potential effects of chronic exposure from these fields continue to be studied and are not 

known at this time. The National Institute of Environmental Health Sciences (NIEHS) directs 

related research through the DOE.

The NIEHS report (NIEHS 1999) contains the following conclusion:

The NIEHS concludes that ELF EMF (extremely low frequency electromagnetic 

field) exposure cannot be recognized as entirely safe because of weak scientific 

evidence that exposure may pose a leukemia hazard. In our opinion, this finding 

is insufficient to warrant aggressive regulatory concern. However, because 

virtually everyone in the United States uses electricity and therefore is routinely 

exposed to ELF EMF, passive regulatory action is warranted such as continued 

emphasis on educating both the public and the regulated community on means 

aimed at reducing exposures. The NIEHS does not believe that other cancers or 

non cancer health outcomes provide sufficient evidence of a risk to currently 

warrant concern.

This statement is not sufficient to cause the staff to change its position with respect to the 

chronic effects of electromagnetic fields. The staff considers the GEIS finding of “UNCERTAIN” 

still appropriate and will continue to follow developments on this issue.

4.9 Socioeconomics

The socioeconomic issues applicable to STP, Units 1 and 2, are shown in Table 4–16 for 

Category 1, Category 2, and one uncategorized issue (environmental justice). Section 2.2.8 of 

this SEIS describes the socioeconomic conditions near STP, Units 1 and 2.

Table 4–16. Socioeconomics during the Renewal Term

Issues GEIS Section Category

Housing impacts 4.7.1 2

Public services: public safety, social services, & tourism & 

recreation

4.7.3, 4.7.3.3, 4.7.3.4, 

4.7.3.6 1 

Public services: public utilities 4.7.3.5 2

Public services: education (license renewal) 4.7.3.1 1
Environmental Impacts of Operation

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Issues GEIS Section Category

Offsite land use (license renewal term) 4.7.4 2

Public Services: transportation 4.7.3.2 2

Historic & archaeological resources 4.7.7 2

Aesthetic impacts (license renewal term) 4.7.6 1

Aesthetic impacts of transmission lines (license renewal term) 4.5.8 1

Environmental justice Not addressed(a) Uncategorized

(a) Guidance for implementing Executive Order 12898 and conducting an environmental justice impact analysis was 

not available prior to the completion of the GEIS. This issue must be addressed in plant-specific reviews.

4.9.1 Generic Socioeconomic Issues

The STPNOC ER, scoping comments, other available data records on STP, Units 1 and 2, were 

reviewed and evaluated for new and significant information. The review included a data 

gathering site visit to STP, Units 1 and 2 (the NRC staff also reviewed other sources of 

information such as applicable permits and data reports as listed in the reference section of this 

SEIS chapter). No new and significant information was identified during this review that would 

change the conclusions presented in the GEIS. Therefore, for these Category 1 issues, impacts 

during the renewal term are not expected to exceed those discussed in the GEIS. For STP, 

Units 1 and 2, the NRC staff incorporates the GEIS conclusions by reference. Impacts for 

Category 2 issues and the uncategorized issue (environmental justice) are discussed in 

Sections 4.9.2 through 4.9.7.

4.9.2 Housing

Appendix C of the GEIS (NRC 1996) presents a population characterization method based on 

two factors—sparseness and proximity. Sparseness measures population density within 20 mi 

(32 km) of the site, and proximity measures population density and city size within 50 mi 

(80 km). Each factor has categories of density and size. A matrix is used to rank the population 

category as low, medium, or high as shown in Figure C.1 of the GEIS.

According to the 2000 Census, an estimated 35,291 people lived within 20 mi (32 km) of STP, 

Units 1 and 2, which equates to a population density of 36 persons per square mile 

(STPNOC 2010). This translates to a Category 1, “most sparse,” population density using the 

GEIS measure of sparseness (less than 40 persons per square mile and no community with 

25,000 or more people within 20 mi). An estimated 255,118 people live within 50 mi (80 km) of 

STP, Units 1 and 2, with a population density of 32 persons per square mile (STPNOC 2010). 

Applying the GEIS proximity measures, STP is classified as proximity Category 1 (no city with 

100,000 or more persons and less than 50 persons per square mile within 50 mi). Therefore, 

according to the sparseness and proximity matrix presented in the GEIS, rankings of 

sparseness Category 1 and proximity Category 1 result in the conclusion that the STP is located 

in a low population area.

Table B-1 of 10 CFR Part 51, Subpart A, Appendix B, states that impacts on housing availability 

are expected to be of SMALL, MODERATE, or LARGE. MODERATE or LARGE housing 

impacts of the workforce associated with refurbishment may be associated with plants located in 
Environmental Impacts of Operation

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sparsely populated areas or in areas with growth control measures that limit housing 

development. Because (a) STPNOC has no planned refurbishment activities and (b) Brazoria 

County and Matagorda County are not subject to growth-control measures that would limit 

housing development, any changes in employment at STP would have little noticeable effect on 

housing availability in these counties. Since STPNOC has no plan to add non-outage 

employees during the license renewal period, employment levels at STP would remain relatively 

constant with no additional demand for permanent housing during the license renewal term. 

Based on this information, there would be no impact on housing during the license renewal term 

beyond what has already been experienced. Therefore, the NRC staff concludes that the 

impacts would be SMALL.

4.9.3 Public Services—Public Utilities

Impacts on public utility services (e.g., water, sewer) are considered SMALL if the public utility 

has the ability to respond to changes in demand and would have no need to add or modify 

facilities. Impacts are considered MODERATE if service capabilities are overtaxed during 

periods of peak demand. Impacts are considered LARGE if additional system capacity is 

needed to meet ongoing demand.

Analysis of impacts on the public water systems considered both plant demand and 

plant-related population growth. Section 2.1.7 of this SEIS describes the permitted withdrawal 

rate and actual use of water for reactor cooling at STP, Units 1 and 2.

Since STPNOC has no plans to add non-outage employees during the license renewal period, 

employment levels at STP would remain relatively unchanged with no additional demand for 

public water services. Public water systems in the region are adequate to meet the demands of 

residential and industrial customers in the area. Therefore, there would be no impact to public 

water services during the license renewal term beyond what is currently being experienced. 

Therefore, the NRC staff concludes that the impacts would be SMALL.

4.9.4 Public Services—Transportation

Table B-1 of Appendix B to Subpart A of 10 CFR Part 51 states that: 

Transportation impacts (level of service) of highway traffic generated...during the 

term of the renewed license are generally expected to be of SMALL significance. 

However, the increase in traffic associated with additional workers and the local 

road and traffic control conditions may lead to impacts of MODERATE or LARGE 

significance at some sites.

The regulation in 10 CFR 51.53(c)(3)(ii)(J) requires all applicants to assess the impacts of 

highway traffic generated by the proposed project on the level of service of local highways 

during the term of the renewed license. Since STPNOC has no plans to add non-outage 

employees during the license renewal period, traffic volume and levels of service on roadways 

in the vicinity of STP, Units 1 and 2, would not change. Therefore, there would be no 

transportation impacts during the license renewal term beyond those already being 

experienced. Therefore, the NRC staff concludes that the impacts would be SMALL.

4.9.5 Offsite Land Use

Table B-1 of Appendix B to Subpart A of 10 CFR Part 51 notes that “significant changes in land 

use may be associated with population and tax revenue changes resulting from license 

renewal.” Section 4.7.4 of the GEIS defines the magnitude of land-use changes as a result of 
Environmental Impacts of Operation

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plant operation during the license renewal term as SMALL when there will be little new 

development and minimal changes to an area’s land-use pattern, as MODERATE when there 

will be considerable new development and some changes to the land-use pattern, and LARGE 

when there will be large-scale new development and major changes in the land-use pattern.

Tax revenue can affect land use because it enables local jurisdictions to provide the public 

services (e.g., transportation and utilities) necessary to support development. Section 4.7.4.1 of 

the GEIS states that the assessment of tax-driven land-use impacts during the license renewal 

term should consider the size of the plant’s tax payments relative to the community’s total 

revenues, the nature of the community’s existing land-use pattern, and the extent to which the 

community already has public services in place to support and guide development. If the plant’s 

tax payments are projected to be small relative to the community’s total revenue, tax driven 

land-use changes during the plant’s license renewal term would be SMALL, especially where 

the community has pre-established patterns of development and has provided public services to 

support and guide development. Section 4.7.2.1 of the GEIS states that if tax payments by the 

plant owner are less than 10 percent of the taxing jurisdiction’s revenue, the significance level 

would be SMALL. If tax payments are 10 to 20 percent of the community’s total revenue, new 

tax-driven land-use changes would be MODERATE. If tax payments are greater than 

20 percent of the community’s total revenue, new tax-driven land-use changes would be 

LARGE. This would be especially true where the community has no pre-established pattern of 

development or has not provided adequate public services to support and guide development. 

As discussed in Sections 4.9.2, 4.9.3, and 4.9.4, it is not expected that there would be any 

change in the staffing levels at STP or increased demand for additional housing, public services 

related to public utilities, and transportation during the license renewal period. Therefore, the 

NRC staff concludes that the impacts would be SMALL.

4.9.5.1 Population-Related Impacts

Since STPNOC has no plans to add non-outage employees during the license renewal period, 

there would be no plant operations-driven population increase in the vicinity of STP, Units 1 

and 2. Therefore, there would be no population-related offsite land use impacts during the 

license renewal term beyond those already being experienced. Therefore, the NRC staff 

concludes that the impacts would be SMALL.

4.9.5.2 Tax Revenue-Related Impacts

As discussed in Chapter 2, STPNOC pays property taxes for STP, Units 1 and 2, to Matagorda 

County, Matagorda County Hospital District, Navigation District #1, Drainage District #3, 

Palacios Seawall District, and the Coastal Plains Groundwater District. Since STPNOC started 

making property tax payments to local jurisdictions, population levels and land use conditions in 

Matagorda County has remained relatively unchanged (STPNOC 2010); therefore, tax revenue 

from STP, Units 1 and 2, has had little or no effect on land use conditions within the county.

Since employment levels at STP, Units 1 and 2, would remain relatively unchanged with no 

increase in the assessed value of STP, Units 1 and 2, annual property tax payments would also 

be expected to remain relatively unchanged throughout the license renewal period. Based on 

this information, there would be no tax-revenue-related offsite land use impacts during the 

license renewal term beyond those already being experienced. Therefore, the NRC staff 

concludes that the impacts would be SMALL.
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4.9.6 Historic and Archaeological Resources

The National Historic Preservation Act (NHPA) requires Federal agencies to consider the effects 

of their undertakings on historic properties. Historic properties are defined as resources that are 

eligible for listing on the National Register of Historic Places (NRHP). The criteria for eligibility 

are listed in 36 CFR 60.4 and include association with significant events in history; association 

with the lives of persons significant in the past; embodiment of distinctive characteristics of type, 

period, or construction; and sites or places that have yielded or are likely to yield important 

information. The historic preservation review process (Section 106 of NHPA) is outlined in 

regulations issued by the Advisory Council on Historic Preservation (ACHP) in 36 CFR Part 800. 

In accordance with 36 CFR 800.8(c), the NRC has elected to use the NEPA process to comply 

with the obligations found under Section 106 of the NHPA.

The issuance of a renewed operating license for a nuclear power plant is a Federal action that 

could affect historic properties on or near the nuclear plant site and transmission lines. In 

accordance with the provisions of the NHPA, the NRC is required to make a reasonable effort to 

identify historic properties included in or eligible for inclusion in the NRHP in the area of 

potential effect (APE). The APE for license renewal is the nuclear power plant site, 

transmission lines, and immediate environs. If historic properties are present, the NRC is 

required to contact the State Historic Preservation Office (SHPO), assess the potential impact, 

and resolve any possible adverse effects of the undertaking (license renewal) on historic 

properties. NRC is also required to notify the SHPO if historic properties would not be affected 

by license renewal or if no historic properties are present. The SHPO is part of the Texas 

Historical Commission (THC) in the State of Texas. This section provides the NRC’s 

assessment of effects from the proposed license renewal action for STP, Units 1 and 2. 

Section 2.2.10 of this SEIS provides specific historic and cultural information near the STP site.

On March 17, 2009, STP initiated informal consultation with the THC regarding the renewal of 

operating licenses for STP, Units 1 and 2. STP concluded in its letter to THC that there would 

be no effect on historic properties from license renewal and associated operation and 

maintenance activities (STPNOC 2010b). The THC responded to STP on October 26, 2009, 

with a determination of “No Historic Properties Affected, Project May Proceed” 

(STPNOC 2010b). The THC response is in the form of a stamp on the last page of the STP 

letter that was sent to the THC, which STP included in its ER for license renewal 

(STPNOC 2010b).

Prior to the site audit in May 2011, NRC contacted the THC concerning license renewal for STP. 

The staff and THC concluded there was no need to meet during the environmental audit to 

discuss cultural resources (NRC 2011a). The THC determined that there were no known issues 

with license renewal for STP and referred the NRC to the THC response to STP on 

October 26, 2009, with the determination of “No Historic Properties Affected, Project May 

Proceed” (STPNOC 2010b).

In accordance with 36 CFR 800.8(c), on January 27, 2011, and February 17, 2011, respectively, 

the NRC initiated consultations on the proposed action by writing to the ACHP and SHPO 

(NRC 2011d, 2011e). In February 2011, the NRC initiated consultation with six Federally 

recognized tribes: the Yselta del Sur Pueblo Tribe, Alabama-Cousahatta Tribe, Kiowa Tribe of 

Oklahoma, the Comanche Nation, Tonkawa Tribe of Oklahoma, and Kickapoo Traditional 

Council (Appendix D contains a copy of these letters for reading convenience). Also in 

February 2011, the NRC initiated consultation with four additional tribes: the Apalachicola Band 

of Creek Indians, Lipan Apache Band of Texas, Pamaque Clan of Coahuila Y Tejas, and the 

Tap Pilam-Coahuiltecan Nation (Appendix D contains a copy of these letters). In its letters, the 
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NRC provided information about the proposed action and the definition of APE. In addition, the 

NRC indicated that the NHPA review would be integrated with the NEPA process, in 

accordance with 36 CFR 800.8. NRC invited participation in the identification and possible 

decisions concerning historic properties and invited participation in the scoping process. Four 

tribes—the Apalachicola Band of Creek Indians, the Kickapoo Traditional Council, the Tonkawa 

Tribe of Oklahoma, and the Tap Pilam-Coahuiltecan Nation—responded to the NRC with 

scoping comments. These comments included concerns with potential accidents, requests to 

re-survey the STP site, requests for notification if historic and cultural resources of cultural 

significance were discovered on the STP site, and statements of no concern with the 

undertaking. NRC responded to the tribes in October 2011 and has taken the comments into 

consideration while preparing this SEIS (Appendix D lists copies of these letters). 

As described in Section 2.2.10, there are no recorded archaeological sites or historic structures 

on the STP site. STPNOC has identified a potential historic gravesite located on the southeast 

boundary of the STP site within the APE. STP staff interviewed descendants of the former 

property owner and confirmed the presence of a grave from the late 1800s; however, little is 

known about the gravesite, and it is not a recorded historic and archaeological resource. The 

NRC staff has confirmed that there are no planned ground-disturbing activities near the 

gravesite and it would be protected from any operation and maintenance activities associated 

with the license renewal term as the activities “would occur several miles from the [grave]site 

and would be conducted in accordance with STP environmental compliance procedures” 

(STPNOC 2011g). 

STPNOC has no planned refurbishment activities associated with license renewal at the STP 

site (STPNOC 2011g). A review of operation and maintenance activities that occur in and 

around the STP site indicates that these activities are limited to the use of existing roads and 

previously disturbed areas and are subject to STP environmental compliance procedures 

(applicable to any future potential land disturbing constructions at STP). 

For the purposes of NHPA Section 106 consultation, the NRC staff concludes a finding of no 

effect to historic properties (36 CFR Section 800.4(d)(1)) based on the following:

• historic and cultural resources located within the APE, 

• tribal input, 

• STP environmental compliance procedures, 

• there will be no refurbishment or ground-disturbing activities associated with 

the relicensing of STP, Units 1 and 2,

• SHPO finding of “No Historic Properties—Affected, Project May Proceed,” 

and 

• the NRC staff’s cultural resource analysis and consultation. 

For the purposes of the NRC staff’s NEPA analysis, in consideration of the conclusion reached 

in the NHPA Section 106 consultation, the NRC staff concludes that potential impacts on 

historic and cultural resources related to STP license renewal would be SMALL.

4.9.7 Environmental Justice

Under Executive Order (EO) 12898 (59 FR 7629), Federal agencies are responsible for 

identifying and addressing, as appropriate, disproportionately high and adverse human health 

and environmental impacts on minority and low-income populations. In 2004, the NRC issued a 
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Policy Statement on the Treatment of Environmental Justice Matters in NRC Regulatory and 

Licensing Actions (69 FR 52040), which states, “The Commission is committed to the general 

goals set forth in EO 12898, and strives to meet those goals as part of its NEPA review 

process.”

The Council on Environmental Quality (CEQ) provides the following information in 

Environmental Justice: Guidance Under the National Environmental Policy Act (CEQ 1997b): 

Disproportionately High and Adverse Human Health Effects.

Adverse health effects are measured in risks and rates that could result in latent 

cancer fatalities, as well as other fatal or nonfatal adverse impacts on human 

health. Adverse health effects may include bodily impairment, infirmity, illness, or 

death. Disproportionately high and adverse human health effects occur when the 

risk or rate of exposure to an environmental hazard for a minority or low-income 

population is significant (as employed by NEPA) and appreciably exceeds the 

risk or exposure rate for the general population or for another appropriate 

comparison group.

Disproportionately High and Adverse Environmental Effects.

A disproportionately high environmental impact that is significant (as employed 

by NEPA) refers to an impact or risk of an impact on the natural or physical 

environment in a low-income or minority community that appreciably exceeds the 

environmental impact on the larger community. Such effects may include 

ecological, cultural, human health, economic, or social impacts. An adverse 

environmental impact is an impact that is determined to be both harmful and 

significant (as employed by NEPA). In assessing cultural and aesthetic 

environmental impacts, impacts that uniquely affect geographically dislocated or 

dispersed minority or low-income populations or American Indian tribes are 

considered.

The environmental justice analysis assesses the potential for disproportionately high and 

adverse human health or environmental effects on minority and low-income populations that 

could result from the operation of STP during the license renewal term. In assessing the 

impacts, the following definitions of minority individuals and populations and low-income 

population were used (CEQ 1997b):

Minority individuals.

Individuals who identify themselves as members of the following population 

groups: Hispanic or Latino, American Indian or Alaska Native, Asian, Black or 

African American, Native Hawaiian or Other Pacific Islander, or two or more 

races, meaning individuals who identified themselves on a Census form as being 

a member of two or more races, for example, Hispanic and Asian.

Minority populations.

Minority populations are identified when (1) the minority population of an affected 

area exceeds 50 percent or (2) the minority population percentage of the affected 

area is meaningfully greater than the minority population percentage in the 

general population or other appropriate unit of geographic analysis.

Low-income population.

Low-income populations in an affected area are identified with the annual 

statistical poverty thresholds from the Census Bureau’s Current Population 

Reports, Series P60, on Income and Poverty.
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Minority Population. According to 2010 Census data, 45.9 percent of the total population 

(approximately 110,201 persons) residing within a 50-mi (80-km) radius of STP identified 

themselves as minority individuals. The largest minority group was Hispanic or Latino (of any 

race) (approximately 82,000 persons or 33.9 percent), followed by Black or African American 

(approximately 23,000 persons or 9.6 percent) (CAPS 2011).

According to 2010 Census data, minority populations in the socioeconomic ROI (Matagorda and 

Brazoria Counties) comprised 47.4 percent of the total two-county population as shown in 

Table 2–17 (USCB 2011). Figure 4–2 shows minority population block groups using 

2010 Census data for race and ethnicity within a 50-mi (80-km) radius of STP.
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Figure 4–2. 2010 Census Minority Block Groups Within a 50-mi Radius of STP

Source: USCB 2012.
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Census block groups were considered minority population block groups if the percentage of the 

minority population within any block group exceeded 45.9 percent (the percent of the minority 

population within the 50-mi radius of STP). A minority population exists if the percentage of the 

minority population within the block group is meaningfully greater than the minority population 

percentage in the 50-mi radius. Minority population block groups are concentrated in the Bay 

City area, El Campo, Freeport, Palacios, and Port Lavaca. Smaller concentrations of minority 

population block groups are found in Angelton and Wharton. The nearest minority population 

(i.e., percentage is meaningfully greater than the percentage in the 50-mi radius) to STP is 

located in Matagorda, Texas. In Matagorda, according to the 2010 Census, approximately 

15 percent of the Matagorda population identified themselves as minority.

Low-Income Population. According to 2006 through 2010 American Community Survey 5-year 

estimates, an average of 11.4 percent of families and 14.2 percent of individuals residing in nine 

counties—all or parts of which are located within a 50-mi radius of STP (Brazoria, Calhoun, 

Colorado, Fort Bend, Jackson, Lavaca, Matagorda, Victoria, and Wharton)—were identified as 

living below the Federal poverty threshold in 2010 (USCB 2010). The 2010 Federal poverty 

threshold was $22,314 for a family of four. 

According to 2006 through 2010 American Community Survey 5-year estimates, the median 

household income for Texas was $49,646, with 16.8 percent of the State population and 

13 percent of families living below the Federal poverty threshold in 2010 (USCB 2011). 

Brazoria County had a lower median household income average ($43,258) and 

lower percentages of individuals (10.6 percent) and families (8.2 percent) living below the 

poverty level when compared to the State average. Matagorda County had a lower household 

income average ($48,508) compared to the State average and higher than Brazoria County, but 

a higher percentage of individuals (18.6 percent) and families (21.6 percent) living below the 

poverty level when compared to Brazoria County and the State (USCB 2011).

Figure 4–3 shows low-income census block groups within a 50-mi (80-km) radius of STP. 

Census block groups were considered low-income population block groups if the percentage of

individuals living below the Federal poverty threshold within any block group exceeded the 

percent of the individuals living below the Federal poverty threshold within the 50-mi radius of 

STP. Similar to the locations of minority population block groups, the majority of low-income 

population block groups are located in the Bay City area, Freeport, Palacios, Port Lavaca, and 

Wharton. Smaller concentrations of minority population block groups are located near Angelton. 

The nearest low-income population to STP is located in Matagorda, Texas.
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Figure 4–3. Census 2010 Low-Income Block Groups Within a 50-mi Radius of STP

Source: USCB 2012
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Analysis of Impacts. The NRC addresses environmental justice matters for license renewal in 

the following ways:

• identifying the location of minority and low-income populations that may be 

affected by the continued operation of the nuclear power plant during the 

license renewal term, 

• determining whether there would be any potential human health or 

environmental effects to these populations and special pathway receptors, 

and

• determining if any of the effects may be disproportionately high and adverse.

Figure 4–2 and Figure 4–3, above, identify the location of minority and low-income populations 

residing within a 50-mi (80-km) radius of STP. This area of impact is consistent with the impact 

analysis for public and occupational health and safety, which also focuses on populations within 

a 50-mi (80-km) radius of the nuclear plant. Chapter 4 presents the assessment of 

environmental and health impacts for each resource area. With the exception of the 

electromagnetic fields/acute effects issue, which the NRC staff concluded has a potential impact 

level of SMALL to MODERATE, the NRC staff concluded that the impact from all the other 

environmental issues would be SMALL.

Potential impacts to minority and low-income populations (including migrant workers or Native 

Americans) would mostly consist of socioeconomic and radiological effects; however, radiation 

doses from continued operations during the license renewal term are expected to continue at 

current levels and would remain below regulatory limits. Chapter 5 of this SEIS discusses the 

environmental impacts from postulated accidents that might occur during the license renewal 

term, which include both design-basis and severe accidents. In both cases, the NRC has 

generically determined that impacts associated with design-basis accidents are SMALL 

because nuclear plants are designed and operated to successfully withstand such accidents, 

and the probability-weighted consequences of severe accidents are SMALL. 

Therefore, based on this information and the analysis of human health and environmental 

impacts presented in Chapters 4 and 5 of this SEIS, there would be no disproportionately high 

and adverse impacts to minority and low-income populations from the continued operation of 

STP during the license renewal term.

As part of addressing environmental justice concerns associated with license renewal, the NRC 

also assessed the potential radiological risk to special population groups (such as migrant 

workers or Native Americans) from exposure to radioactive material received through their 

unique consumption and interaction with the environment patterns. These include subsistence 

consumption of fish, native vegetation, surface waters, sediments, and local produce; 

absorption of contaminants in sediments through the skin; and inhalation of airborne radioactive 

material released from the plant during routine operation. This analysis is presented below.

Subsistence Consumption of Fish and Wildlife. The special pathway receptors analysis is an 

important part of the environmental justice analysis because consumption patterns may reflect 

the traditional or cultural practices of minority and low-income populations in the area, such as 

migrant workers or Native Americans.

Section 4-4 of EO 12898 (1994) directs Federal agencies, whenever practical and appropriate, 

to collect and analyze information on the consumption patterns of populations that rely 

principally on fish or wildlife or both for subsistence and to communicate the risks of these 

consumption patterns to the public. In this SEIS, the NRC considered whether there were any 
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means for minority or low-income populations to be disproportionately affected by examining 

impacts to American Indians, Hispanics, migrant workers, and other traditional lifestyle special 

pathway receptors. Special pathways take into account the levels of radiological and 

nonradiological contaminants in native vegetation, crops, soils and sediments, groundwater, 

surface water, fish, and game animals on or near STP.

The following is a summary discussion of the NRC’s evaluation from Section 4.8.2 of the REMP 

that assesses the potential impacts for subsistence consumption of fish and wildlife near the 

STP site.

STPNOC has an ongoing, comprehensive REMP to assess the impact of STP operations on the 

environment. To assess the impact of nuclear power plant operations, samples are collected 

annually from the environment and analyzed for radioactivity. A nuclear power plant effect 

would be indicated if the radioactive material detected in a sample was significantly larger than 

background levels. Two types of samples are collected. The first type, control samples, is 

collected from areas that are beyond the measurable influence of the nuclear power plant or any 

other nuclear facility. These samples are used as reference data to determine normal 

background levels of radiation in the environment. These samples are then compared with the 

second type of samples, indicator samples, collected near the nuclear power plant. Indicator 

samples are collected from areas where any contribution from the nuclear power plant will be at 

its highest concentration. These samples are then used to evaluate the contribution of normal 

nuclear power plant operations to radiation or radioactivity levels in the environment. An effect 

would be indicated if the radioactivity levels detected in an indicator sample was significantly 

larger than the control sample or background levels.

Samples of environmental media are collected from the aquatic and terrestrial pathways in the 

vicinity of STP. The aquatic pathways include surface water, groundwater, drinking water, fish, 

crab, shrimp, oyster, and shoreline sediment. The terrestrial pathways include airborne 

particulates, food products (i.e., leafy vegetables such as cabbage and various edible greens, 

are collected from gardens and farms in the vicinity of STP), beef, poultry, wild animal meat 

(i.e., waterfowl, deer, rabbits, and alligator), and broadleaf vegetation. In 2010, analyses 

performed on samples of environmental media showed no significant or measurable radiological 

impact above background levels from normal STP operations (STPNOC 2011). For this final 

SEIS, the NRC staff reviewed the results of STP’s REMP data for 2012 and concluded that 

there were no significant of measurable radiological impacts above background levels from 

normal STP operations (STPNOC 2013b)

Conclusion. Based on the radiological environmental monitoring data from STP, the NRC finds 

that no disproportionately high and adverse human health impacts would be expected in special 

pathway receptor populations in the region as a result of subsistence consumption of water, 

local food, fish, and wildlife.

4.10 Evaluation of New and Potentially Significant Information

The staff has not identified new and significant information on environmental issues related to 

operation during the renewal term. The staff also determined that information provided during 

the public comment period did not identify any new issue that requires site-specific assessment. 

The staff reviewed the discussion of environmental impacts associated with operation during the 

renewal term in the GElS and has conducted its own independent review, including public 

involvement process (e.g., public meetings) to identify issues with new and significant 

information.
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New and significant information is information that identifies a significant environmental issue 

not covered in the GEIS and codified in Table B-1 of 10 CFR Part 51, Subpart A, Appendix B, or 

information that was not considered in the analyses summarized in the GEIS and that leads to 

an impact finding that is different from the finding presented in the GEIS and codified in 

10 CFR Part 51.

In accordance with 10 CFR 51.53(c), the ER submitted by the applicant must provide an 

analysis of the Category 2 issues in Table B-1 of 10 CFR Part 51, Subpart A, Appendix B. 

Additionally, it must discuss actions to mitigate any adverse impacts associated with the 

proposed action and environmental impacts of alternatives to the proposed action. In 

accordance with 10 CFR 51.53(c)(3), the ER does not need to contain an analysis of any 

Category 1 issue unless there is significant new information on a specific issue.

The NRC also has a process for identifying new and significant information. That process is 

described in NUREG-1555, Supplement 1, Standard Review Plans for Environmental Reviews 

for Nuclear Power Plants, Supplement 1: Operating License Renewal (NRC 1999b, 2013e). 

The search for new information includes: 

• review of an applicant’s ER and the process for discovering and evaluating 

the significance of new information, 

• review of public comments,

• review of environmental quality standards and regulations, 

• coordination with Federal, State, and local environmental protection and 

resource agencies, and 

• review of the technical literature. 

New information discovered by the staff is evaluated for significance using the criteria set forth 

in the GEIS. For Category 1 issues where new and significant information is identified, 

reconsideration of the conclusions for those issues is limited in scope to the assessment of the 

relevant new and significant information; the scope of the assessment does not include other

facets of an issue that are not affected by the new information.

4.11 Environmental Issues Contained in the Revised 10 CFR Part 51, 

“Environmental Protection Regulations for Domestic Licensing and Related 

Regulatory Functions”

As described in Section 1.4 of this SEIS, the NRC has published a final rule (78 FR 37282, 

June 20, 2013) revising its environmental protection regulation, 10 CFR Part 51, “Environmental 

protection regulations for domestic licensing and related regulatory functions.” The final rule 

consolidates similar Category 1 and 2 issues, changes some Category 2 issues into Category 1 

issues, and consolidates some of those issues with existing Category 1 issues. The revised 

rule also adds new Category 1 and 2 issues. The new Category 1 issues include geology and 

soils, exposure of terrestrial organisms to radionuclides, exposure of aquatic organisms to 

radionuclides, human health impact from chemicals, and physical occupational hazards. 

Radionuclides released to groundwater, effects on terrestrial resources (non-cooling system 

impacts), minority and low-income populations (i.e., environmental justice), and cumulative 

impacts were added as new Category 2 issues. Except for cumulative impacts, this section 

addresses the direct and indirect effects associated with these new Category 1 and Category 2 
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issues. The cumulative impacts assessment is presented in Section 4.12. Table 4–16a shows 

the newly revised 10 CFR Part 51 issues. 

Table 4–16a. Newly Revised 10 CFR Part 51 Issues 

Issues GEIS Section Category

Geology and soils 4.4 1

Radionuclides released to groundwater 4.5.1.2 2

Exposure of terrestrial organisms to radionuclides 4.6.1.1 1

Exposure of aquatic organisms to radionuclides 4.6.1.2 1

Human health impacts from chemicals 4.9.1.1.2 1

Physical occupational hazards 4.9.1.1.5 1

Environmental justice (minority & low-income populations) 4.10 2

Cumulative Impacts 4.13 2

Terrestrial Resources 4.6.1.1 2

Source: NRC 2013d; 78 FR 37282.

4.11.1 Geology and Soils

With respect to the geologic environment of a plant site, the final rule amends Table B-1 in 

Appendix B, Subpart A, to 10 CFR Part 51 by adding a new Category 1 issue, “Geology and 

soils.” This new issue has an impact level of SMALL. This new Category 1 issue considers 

geology and soils from the perspective of those resource conditions or attributes that can be 

affected by continued operations during the renewal term. An understanding of geologic and 

soil conditions has been well established at all nuclear power plants and associated 

transmission lines during the current licensing term, and these conditions are expected to 

remain unchanged during the 20-year license renewal term for each plant. The impact of these 

conditions on plant operations and the impact of continued power plant operations and 

refurbishment activities on geology and soils are SMALL for all nuclear power plants and not 

expected to change appreciably during the license renewal term. Operating experience shows 

that any impacts to geologic and soil strata would be limited to soil disturbance from 

construction activities associated with routine infrastructure renovation and maintenance 

projects during continued plant operations. Implementing best management practices would 

reduce soil erosion and subsequent impacts on surface water quality. Information in 

plant-specific SEISs prepared to date and reference documents has not identified these impacts 

as being significant.

Section 2.2.3 of this SEIS describes the local and regional geologic environment relevant to 

STP. The staff did not identify any new and significant information with regard to this 

Category 1 (generic) issue based on review of the STPNOC’s ER, the public scoping process, 

or as a result of the environmental site audit. As discussed in Chapter 3 of this SEIS and as 

identified in the STPNOC’s ER (STPNOC 2010b), STPNOC has no plans to conduct major 

refurbishment or replacement actions associated with license renewal to support the continued 

operation of STP. Furthermore, STPNOC anticipates no major changes including construction 

or other ground-disturbing activities, and the staff anticipates that ongoing maintenance 

activities would primarily be confined to previously disturbed areas or existing ROWs. Based on 
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this information, it is expected that any incremental impacts on geology and soils during the 

license renewal term would be SMALL. 

4.11.2 Radionuclides Released to Groundwater

With respect to groundwater quality, the final rule amends Table B-1 in Appendix B, Subpart A, 

to 10 CFR Part 51 by adding a new Category 2 issue, “Radionuclides released to groundwater,” 

with an impact level range of SMALL to MODERATE, to evaluate the potential impact of 

discharges of radionuclides from plant systems into groundwater. This new Category 2 issue 

has been added to evaluate the potential impact to groundwater quality from the discharge of 

radionuclides from plant systems, piping, and tanks. The staff evaluates this issue for STP in 

Section 4.4.3 of this SEIS. Based on its review, the staff concludes the impacts are SMALL. 

4.11.3 Exposure of Aquatic Organisms and Terrestrial Resource to Radionuclides

With respect to the aquatic and terrestrial organisms, the final rule amends Table B-1 in 

Appendix B, Subpart A, to 10 CFR Part 51 by adding two new Category 1 issues, “Exposure of 

aquatic organisms to radionuclides” and “Exposure of terrestrial organisms to radionuclides,” 

among other changes. These new Category 1 issues consider the impacts to aquatic and 

terrestrial organisms from exposure to radioactive effluents discharged from a nuclear power 

plant during the license renewal term. An understanding of the radiological conditions in the 

aquatic and terrestrial environment from the discharge of radioactive effluents within NRC 

regulations has been well established at nuclear power plants during their current licensing 

term. Based on this information, the staff concluded that the doses to aquatic and terrestrial 

organisms (i.e., biota) are expected to be well below exposure guidelines developed to protect 

these organisms and assigned an impact level of SMALL.

The staff has not identified any new and significant information related to the exposure of 

aquatic organisms to radionuclides during its independent review of STPNOC’s ER, the site 

audit, and the scoping process. Section 2.1.2 of this SEIS describes the applicant’s Radioactive 

Waste Management Program to control radioactive effluent discharges to ensure that they 

comply with NRC regulations in 10 CFR Part 20. Section 4.8.2 of this SEIS contains the staff’s 

evaluation of the STPNOC’s radioactive effluent and radiological environmental monitoring 

programs. STPNOC’s radioactive effluent and radiological environmental monitoring programs 

provide further support for the conclusion that the impacts of aquatic and terrestrial organisms 

from radionuclides are SMALL. 

The staff concludes that there would be no impacts to aquatic and terrestrial organisms (biota) 

from radionuclides beyond those impacts contained in Table B-1 in Appendix B, Subpart A, to 

10 CFR Part 51 of the revised rule; therefore, the impacts to aquatic and terrestrial organisms 

from radionuclides are SMALL.

4.11.4 Effects on Terrestrial Resources (Non-cooling System Impacts)

With respect to the terrestrial organisms, the final rule amends Table B-1 in Appendix B, 

Subpart A, to 10 CFR Part 51 by expanding the Category 2 issue, “Refurbishment impacts,” 

among others, to include normal operations, refurbishment, and other supporting activities 

during the license renewal term. This issue remains a Category 2 issue with an impact level 

range of SMALL to LARGE; however, the revised rule renames this issue “Effects on terrestrial 

resources (non-cooling system impacts).” 
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Section 2.2.7 describes the terrestrial resources on and in the vicinity of the STP site, and 

Section 2.2.8 describes protected species and habitats. Prior to plant construction, much of the 

12,220-ac (4,945-ha) STP site was cropland and rangeland. Approximately 8,000 ac (3,200 ha) 

of the site were disturbed and modified by plant construction and related activities. 

As detailed in Section 2.2.1 of this SEIS, the STP operations area consisting of the reactor 

buildings and support facilities totals approximately 111 ac (45 ha), with the MCR encompassing 

7,000 ac (2,833 ha). Another 1,700 ac (688 ha) is natural lowland habitat. The rest of the site is 

mostly undeveloped land; a portion of which, east of the MCR, is leased for cattle grazing. As 

discussed in Chapter 3 of this SEIS and according to the applicant’s ER (STPNOC 2010b), 

STPNOC has no plans to conduct refurbishment or replacement actions associated with license 

renewal to support the continued operation of STP. Further, as previously discussed in 

Section 4.7, STPNOC anticipates that continued operations and maintenance will not involve 

any new construction or other ground-disturbing activities, including changes to existing land 

use conditions in either natural or developed areas. Based on the staff’s independent review, 

the staff concurs that any operation and maintenance activities that STPNOC might otherwise 

undertake during the renewal term, such as maintenance and repair of plant infrastructure (e.g., 

roadways, piping installations, onsite transmission lines, fencing, and other security 

infrastructure), likely would be confined to previously disturbed areas of the plant site. 

Therefore, the staff expects non-cooling system impacts on terrestrial resources during the 

license renewal term to be SMALL.

4.11.5 Human Health Impacts From Chemicals and Physical Occupational Hazards

With respect to the human health, the final rule amends Table B-1 in Appendix B, Subpart A, to 

10 CFR Part 51 by adding two new Category 1 issues, “Human health impact[s] from chemicals” 

and “Physical occupational hazards.” The first issue considers the impacts from chemicals to 

plant workers and members of the public. The second issue only considers the nonradiological 

occupational hazards of working at a nuclear power plant. An understanding of these 

nonradiological hazards to nuclear power plant workers and members of the public have been 

well established at nuclear power plants during those plants’ current licensing terms. The 

impacts from chemical hazards are expected to be minimized through the applicant’s use of 

good industrial hygiene practices as required by permits and Federal and State regulations 

(e.g., in compliance with the Occupational Safety and Health Administration’s regulation on 

chemical hazard and the use of the Material Data Sheet for the respective facilities). Also, the 

impacts from physical hazards to plant workers will be of small significance if workers adhere to 

safety standards and use protective equipment as required by Federal and State regulations 

(e.g., Occupational Safety and Health Administration rules for industrial safety such as 

mitigation measures for asphyxiation concerns, working in an enclosed space, or with overhead 

loads). The impacts to human health for each of these new issues from continued plant 

operations are SMALL.

The staff has not identified any new and significant information related to these nonradiological 

issues during its independent review of STPNOC’s ER, the site audit, the scoping process, and 

comments on the draft SEIS. Therefore, the staff concludes that there would be no impact to 

human health from chemicals or physical hazards (i.e., industrial hazard) beyond those impacts 

described in Table B-1 in Appendix B, Subpart A, to 10 CFR Part 51 of the revised rule and; 

therefore, the impacts are SMALL.
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4.11.6 Environmental Justice

With respect to environmental justice concerns, the final rule amends Table B-1 in Appendix B, 

Subpart A, to 10 CFR Part 51 by adding a new Category 2 issue, “Minority and low-income 

populations,” to evaluate the impacts of continued operations and any refurbishment activities 

during the license renewal term on minority populations and low-income populations living in the 

vicinity of the plant. Environmental justice was listed in Table B-1 as a concern, prior to this 

revised rule, but was not evaluated in the 1996 GEIS; therefore, it is addressed in each SEIS. 

Consistent with this requirement, the staff evaluates this issue in Section 4.9.7 of this SEIS. 

4.11.7 Cumulative Impacts

With respect to cumulative impacts, the final rule amends Table B-1 in Appendix B, Subpart A, 

to 10 CFR Part 51 by adding a new Category 2 issue, “Cumulative impacts,” to evaluate the 

potential cumulative impacts of license renewal. The staff evaluates this issue in Section 4.12 

of this SEIS. 

4.12 Cumulative Impacts

As described in Section 1.4 of this SEIS, the NRC has approved a revision to its environmental 

protection regulation, 10 CFR Part 51. With respect to cumulative impacts, the final rule

amends Table B-1 in Appendix B, Subpart A, to 10 CFR Part 51 by adding a new Category 2 

issue, “Cumulative impacts,” to evaluate the potential cumulative impacts of license renewal. 

The staff considered potential cumulative impacts in the environmental analysis of continued 

operation of STP nuclear plant during the 20-year license renewal period. Cumulative impacts 

may result when the environmental effects associated with the proposed action are overlaid or 

added to temporary or permanent effects associated with other past, present, and reasonably 

foreseeable actions. Cumulative impacts can result from individually minor, but collectively 

significant, actions taking place over a period of time. It is possible that an impact that may be 

SMALL by itself could result in a MODERATE or LARGE cumulative impact when considered in 

combination with the impacts of other actions on the affected resource. Likewise, if a resource 

is regionally declining or imperiled, even a SMALL individual impact could be important if it 

contributes to or accelerates the overall resource decline.

For the purposes of this cumulative analysis, past actions are those before the receipt of the 

license renewal application. Present actions are those related to the resources at the time of 

current operation of the power plant, and future actions are those that are reasonably 

foreseeable through the end of plant operation including the period of extended operation. 

Therefore, the analysis considers potential impacts through the end of the current license terms 

as well as the 20-year renewal license term. The geographic area over which past, present, 

and reasonably foreseeable actions would occur is dependent on the type of action considered 

and is described below for each resource area.

The staff describes the incremental impacts of the proposed action (i.e., STP license renewal) in 

Sections 4.1-4.9 of this SEIS. To evaluate cumulative impacts, the incremental impacts of the 

proposed action are combined with other past, present, and reasonably foreseeable future 

actions regardless of what agency (Federal or non-Federal) or person who undertakes such 

actions. The staff used the information provided in the ER; responses to requests for additional 

information; information from other Federal, State, and local agencies; scoping comments; and 

information gathered during the audit at the STP site to identify other past, present, and 
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reasonably foreseeable actions. To be considered in the cumulative analysis, the staff 

determined if the project would occur within the noted geographic areas of interest and within 

the period of extended operation, if it was reasonably foreseeable, and if there would be 

potential overlapping effect with the proposed project. For past actions, consideration within the 

cumulative impacts assessment is resource and project specific. In general, the effects of past 

actions are included in the description of the affected environment in Chapter 2, which serves as 

the baseline for the cumulative impacts analysis. However, past actions that continue to have 

an overlapping effect on a resource potentially affected by the proposed action are considered 

in the cumulative analysis.

Other actions and projects were identified during this review and considered in the staff’s 

independent analysis of the potential cumulative effects. Examples of other actions and 

projects that were considered in this analysis include the following:

• proposed STP, Units 3 and 4,

• White Stallion Energy Center (WSEC),

• LCRA–San Antonio Water System (SAWS) Project,

• Mary Rhodes Pipeline Phase II, and 

• Brazos Bend State Park, Mad Island Marsh Preserve, Mad Island Wildlife 

Management Area, Big Boggy National Wildlife Refuge, and the Texas Prairie 

Wetland Project.

The complete description of each of the projects and actions that were considered are listed in 

the discussions of the following sections. 

4.12.1 Land Use

As discussed in Section 4.1 of this SEIS, onsite land use and powerline ROW conditions are not

expected to change during the license renewal term for STP. Therefore, activities associated 

with continued reactor operations during the license renewal term are not expected to change

the use and management of STPNOC’s lands on the STP site. Therefore, cumulative impacts 

of land use are SMALL.

4.12.2 Air Quality

This section addresses the direct and indirect effects of license renewal on air quality resources 

when added to the aggregate effects of other past, present, and reasonably foreseeable future 

actions. The geographic area considered in the cumulative air quality analysis is the county of 

the proposed action because air quality designations for criteria air pollutants are generally 

made at the county level. Counties are further grouped together based on a common air 

shed—known as an air quality control region (AQCR)—to provide for the attainment and 

maintenance of the National Ambient Air Quality Standards (NAAQS). The STP site is located 

in Matagorda County, Texas, which is part of the Metropolitan Houston-Galveston Intrastate 

AQCR (40 CFR 81.38). Additional counties in this AQCR include Austin, Brazoria, Chambers, 

Colorado, Fort Bend, Galveston, Harris, Liberty, Montgomery, Walker, Waller, and Wharton 

Counties.

In evaluating the potential impacts on air quality associated with license renewal, the NRC staff 

uses as its baseline the existing air quality conditions described in Section 2.2.2 of this SEIS. 

These baseline conditions encompass the existing air quality conditions (EPA’s NAAQS county 
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designations) potentially affected by air emissions from continued operations. Section 2.2.2 

summarizes the air quality designation status for Matagorda County as well as other counties in 

the Metropolitan Houston-Galveston Intrastate AQCR. As noted in Section 2.2.2, EPA regulates 

six criteria pollutants under the NAAQS. These pollutants are carbon monoxide, lead, nitrogen 

dioxide, ozone, sulfur dioxide, and particulate matter. Matagorda County is designated as 

unclassified or in attainment for all NAAQS criteria pollutants. All other counties in this AQCR 

are designated as unclassified or in attainment with respect to the NAAQS criteria pollutants, 

except Brazoria County, which is classified nonattainment/severe relative to the 8-hour ozone 

standard.

Criteria pollutant air emissions from the STP site are presented in Section 2.2.2.1. These 

emissions are principally from standby diesel generators and conform to Texas State air 

emission requirements in 30 TAC 101.10 (Texas Administrative Code). Continued operations of 

the STP site would result in annual air emissions comparable to those noted in Section 2.2.2.1. 

Assuming an average annual emission rate of 58.62 tons per year of total emissions from all 

sources, an additional 20 years of operation would result in approximately 1,172.4 tons 

(1,066.9 metric tons) of total emissions from all sources. There is no planned site refurbishment 

associated with license renewal; therefore, there are no additional air emissions beyond those 

noted in Section 2.2.2.1 for normal operations.

Foreseeable projects that could contribute meaningfully to cumulative impacts to air quality 

include the construction and operation of STP, Units 3 and 4, and the construction and 

operation of the WSEC, a 1,320 mW coal and petroleum coke plant located about 5 mi (8 km) 

northeast of the STP site (MCEDC 2011).

In September 2007, STPNOC submitted COL applications to the NRC for two new nuclear units 

on the STP site. If approved, STPNOC would construct the new units adjacent to the currently 

operating Units 1 and 2. Construction activities would cause some localized temporary 

air-quality effects because of emissions and fugitive dust from operation of the earth-moving 

and material-handling equipment. Emissions from workers’ vehicles and motorized construction 

equipment exhaust would be temporary. NRC assumed that construction crews would use 

dust-control practices to control and reduce fugitive dust. STPNOC proposed such activities 

during construction of proposed Units 3 and 4 (STPNOC 2010b). Section 111.145 of TCEQ’s 

regulations requires dust suppression control during the construction of facilities and parking 

lots. Construction activities and their effect on air quality will be similar for the WSEC coal plant. 

It is unlikely that construction of the two projects would overlap because WSEC is scheduled to 

begin construction in 2012, 2 years earlier than the proposed construction of proposed Units 3 

and 4.

During operations, two new nuclear plants would have similar air emissions, primarily from 

backup diesel generators, to those of existing STP, Units 1 and 2. Because air emissions would 

be similar for the new nuclear plants, the NRC expects similar air permitting conditions and 

regulatory requirements as that for Units 1 and 2. In STPNOC’s ER for Units 3 and 4, STPNOC 

stated that “[a]ir emissions sources would be managed in accordance with Federal, Texas, and 

local air quality control laws and regulations.” Likewise, NRC assumes that the WSEC facility 

would be operated in accordance with Federal, Texas, and local air quality control laws and 

regulations. Effluents from power plants such as the WSEC are typically released through 

stacks and with significant vertical velocity. Section 8.3.1 of this SEIS characterizes the impacts 

for the emissions from similar plants as being clearly noticeable, but given existing regulatory 

regimens, permit requirements, and emissions controls, the coal-fired plant would not 

destabilize air quality.
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Potential cumulative effects of global climate change (GCC) and increases in average annual 

temperatures, higher probabilities of extreme heat events, higher occurrences of extreme 

rainfall (intense rainfall or drought), and changes in the wind patterns could affect 

concentrations of the air pollutants and their long-range transport because their formation 

partially depends on the temperature and humidity and is a result of the interactions between 

hourly changes in the physical and dynamic properties of the atmosphere, atmospheric 

circulation features, wind, topography, and energy use (IPCC 2010).

The NRC staff examined the cumulative effects of the continued operation of STP, Units 1 

and 2, the construction and operation of STP, Units 3 and 4, and the construction and operation 

of the WSEC coal plant. The cumulative impacts on criteria pollutants from emissions of 

effluents from the STP site and the WSEC would be noticeable, principally as a result of the 

contribution of WSEC, but not destabilizing. The NRC staff concludes that cumulative impacts 

from other past, present, and reasonably foreseeable future actions on air quality resources in 

the geographic areas of interest would be MODERATE.

4.12.3 Water Resources

This section addresses the direct and indirect effects of license renewal on water resources 

when added to the aggregate effects of other past, present, and reasonably foreseeable future 

actions. As described in Sections 4.3 and 4.4, the incremental impacts on water resources from 

continued operations during the proposed license renewal term would be SMALL. This analysis 

considers two primary geographic areas of interest. For the lower Colorado River, the 

geographic area of interest is the drainage basin of the Colorado River and Matagorda Bay, 

encompassed by Region K (i.e., the LCRA) of the Texas statewide water plan (LCRWPG 2010). 

For cumulative impacts on groundwater resources, the geographic area of interest generally 

focuses on the CPGCD and potentially affected aquifer systems. The CPGCD has the same 

boundaries as Matagorda County. 

For the Shallow Chicot Aquifer, which could be affected by seepage and spills, the area of 

interest extends from recharge areas in Matagorda County to downgradient discharge areas 

along the Colorado River. For the Deep Chicot Aquifer, the area of interest extends from 

recharge areas in Wharton County to Matagorda Bay. 

The Colorado River and Chicot aquifers are hydraulically connected. As such, this review 

focused on the projects and activities that would use groundwater or could affect the Chicot 

aquifers beneath the STP site or would withdraw or discharge water to the Colorado River within 

their respective geographic areas.

For the purposes of this analysis, it is notable that State-designated River Authorities, such as 

the LCRA (Section 2.2.4.1), act as managers and suppliers of surface water while Groundwater 

Conservation Districts act as managers and permitting authorities for groundwater within their 

respective areas. Overall water resources planning at the regional level is performed by the 

designated regions, and the TWDB brings the Regional Water Plans together to adopt the State 

Water Plan. Regional and State-level water planning consider demands, supplies, and future 

development of both surface and groundwater resources across the State of Texas 

(NRC 2011b).

4.12.3.1 Cumulative Impacts on Surface Water Resources

In addition to continued operation of STP, Units 1 and 2, the NRC staff identified several other 

past, present, and foreseeable projects (NRC 2011b). These projects include the proposed 

STP, Units 3 and 4, the WSEC, the LCRA–SAWS Project, and the Mary Rhodes Pipeline 
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Phase II Project, in addition to the existing water use for municipal, irrigation, industrial, and 

instream uses. NRC and USACE (2011b) also considered potential effects of GCC on water 

supply in Region K, in which STP, Units 1 and 2, is located.

The projected average long-term consumptive surface water use of proposed STP, Units 3 

and 4, would be 37,430 ac-ft/yr (46.2 million m3/yr) at 100 percent load factor (NRC 2011b). 

The projected consumptive use for STP, Units 3 and 4, is approximately 2.6 percent of the 

estimated water available to users in the Matagorda County portion of Region K in the 2030 to 

2060 timeframe, which is estimated to be 145,540 ac-ft/yr (179.5 million m3/yr) 

(LCRWPG 2010). Because the incremental water use of proposed STP, Units 3 and 4, is a 

small percentage of the water available to the local region and would not require additional 

allocation over the current water right held by STPNOC, the NRC staff concludes that the 

incremental impact of water use for STP, Units 3 and 4, on the Colorado River would be 

minimal.

Although its future is uncertain because of continuing legal action, a water-sharing project 

between the LCRA and the SAWS, involving Regions K and L, could affect water resources in 

the region. An off-channel storage reservoir in Wharton County is proposed. The planned 

project would provide 377,000 ac-ft/yr (465 million m3

/yr) of water to Regions K and L, and 

Region L would receive 150,000 ac-ft/yr (185 million m3

/yr) from Region K starting in the 

2020 decade (NRC 2011b). The LCRWPG has considered the effects of the LCRA–SAWS 

Project while estimating the water availability in its 2011 Region Water Plan (LCRWPG 2010).

The WSEC is a 1,320-MW power plant, proposed to be located in Matagorda County near 

Farm-to-Market (FM) Road 2668, 1 mi (1.6 km) south of the Port of Bay City, approximately 5 mi 

(8 km) northeast of the STP site. On October 13, 2008, proponents for WSEC applied to LCRA 

for a new firm water supply of 22,000 ac-ft/yr (27 million m3

/yr), with the total diversion from the 

Colorado River estimated at 29,750 ac-ft/yr (37 million m3

/yr), accounting for delivery losses 

(NRC 2011b). The total WSEC withdrawal would be about 2 percent of the estimated water 

available to Matagorda County users in the 2030 to 2060 timeframe (LCRWPG 2010). Because 

the incremental water withdrawal for WSEC is a small percentage of the water available to the 

local region, the NRC staff concludes that the impact of WSEC withdrawal on the region’s water 

supply would be minimal.

The City of Corpus Christi has a water right amounting to 35,000 ac-ft/yr (43 million m3/yr) from 

the Colorado River (NRC 2011b). Water planning of the City of Corpus Christi indicates that the 

city may start to use its currently unused water rights from the Colorado River by 2020 or 

sooner, depending on demand (City of Corpus Christi 2011). Although the City of Corpus 

Christi does not currently use its water rights from the Colorado River, these rights are 

accounted for in Region K water availability planning. To use its water rights from the Colorado 

River, the City of Corpus Christi would build Phase II of Mary Rhodes Pipeline from Bay City to 

Lake Texana to tie into the existing Phase I of the pipeline that delivers water from Lake Texana 

to the city (NRC 2011b). The City of Corpus Christi water right would represent approximately 

2.4 percent of the estimated water available to Matagorda County users in the 2030 to 2060

timeframe (LCRWPG 2010). Because the incremental water withdrawal by the City of Corpus 

Christi is a small percentage of the water available to the local region, the NRC staff concludes 

that the impact of the City of Corpus Christi withdrawal on the region’s water supply would be 

minimal.

Freshwater inflow needs for Matagorda Bay represent the only use of lower Colorado River 

waters downstream of the STP site (NRC 2011b). The LCRA, TCEQ, Texas Parks and Wildlife 

Department, and the TWDB estimated Matagorda Bay freshwater inflow needs (LCRA et 
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al. 2006). LCRA et al. (2006) estimated a target for freshwater inflow that would optimize 

productivity of selected estuarine species and the critical freshwater inflow that would promote 

repopulation of finfish and shellfish following a dry period. The average target freshwater inflow 

was established at 118,975 ac-ft/mo (146.7 million m3

/mo) or 1,972 cfs (55 m3/s). The critical 

freshwater inflow was established at 36,000 ac-ft/mo (44 million m3

/mo) or 597 cfs (17 m3/s). 

Recommendations made in LRCA et al. (2006) with regard to inflow needs continue to be 

reviewed by the TCEQ, and, if formally established, they could make the cited volume of surface 

water discharge unavailable for other uses (NRC 2011b).

NRC and USACE (NRC 2011b) considered the U.S. Global Change Research Program’s 

(USGCRP’s) most recent compilation of the state of knowledge relative to GCC effects 

(USGCRP 2009). NRC and USACE reviewed forecasted increases in temperature and 

decreases in precipitation for the Colorado River watershed reported by USGCRP (2009) and 

determined that GCC could affect water supply in the Colorado River Basin by reducing surface 

runoff and increasing evapotranspiration during the period of STP, Units 1 and 2, extended 

operations. The USGCRP has identified that the region is likely to experience water conflicts by 

2025 because of increasing population and potential endangered species’ needs 

(USGCRP 2009). The NRC and USACE (NRC 2011b) concluded that while the GCC-related 

changes may not be insignificant nationally or globally, their impact on STP regional water 

resources would not be destabilizing. Thus, the NRC staff concludes that GCC effects would 

not substantially add to regional surface water cumulative impacts during the license renewal 

term for STP, Units 1 and 2.

Historically, the waters of the Colorado River Basin have been extensively used, and the region 

has surface water planning, allocation, and development systems in place to manage the use of 

its limited surface water resources. The cumulative impact on surface water use in Region K 

relative to the unaltered conditions prior to these uses, from past and present diversions and 

reasonably foreseeable future projects, would noticeably alter but not destabilize the surface 

water resource. Nevertheless, due to the potential impacts associated with water use conflicts 

and maintenance of Colorado River flows to Matagorda Bay, the NRC staff concludes that 

cumulative impacts on surface water resources during the license renewal term would be 

MODERATE. 

4.12.3.2 Cumulative Impacts on Groundwater Resources 

Water drawn from the Shallow Chicot Aquifer in the vicinity of the STP site is slightly saline, and, 

consequently, it is used primarily for livestock watering. Offsite livestock wells are located close 

to the STP site boundary, and four are located on leased grazing land within the STP site 

(i.e., between the MCR and the Colorado River) (see Section 2.2.5.1). No groundwater is

withdrawn from the Shallow Chicot Aquifer for use by STP, Units 1 and 2. STP operation does 

result in seepage from the MCR entering the Upper Shallow Aquifer, and the MCR water carries 

with it the constituents contained in plant cooling water (e.g., tritium, TDS) (NRC 2011b; 

STPNOC 2010b). Operation of the plant has also resulted in leaks and releases to the Shallow 

Aquifer within the protected area (e.g., the TDS line leaks and steam condensate discharge) 

(MACTEC 2009). These releases have not substantially affected the groundwater quality within 

the STP site, and impacts on groundwater quality off site would be less. Specifically, for the 

Shallow Chicot Aquifer, tritium levels remain below the EPA primary DWS, and TDS 

concentrations remain within the range defining a slightly saline groundwater. Because of the 

reasons presented above, the NRC staff concludes that cumulative impacts on groundwater use 

and quality during the license renewal term, related to the Shallow Chicot Aquifer, would be 

SMALL. 
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In contrast, water drawn from the Deep Chicot Aquifer is of higher quality. Aside from the 

existing STP-owned groundwater wells completed in the Deep Chicot Aquifer that supply STP, 

Units 1 and 2, the closest wells to the STP site completed in the Deep Chicot Aquifer are the 

public water supply wells in the communities of Selkirk and Exotic Isle, which are located 

adjacent to the STP site eastern boundary (see Section 2.2.5). Wells for these communities are 

approximately 1 mi (1.6 km) from the nearest STP production well and 3.75 mi (6 km) from STP, 

Units 1 and 2. Review of other existing or planned projects in the surrounding area indicates 

groundwater use by Equistar Chemicals LP’s Matagorda facility, the OXEA Corporation Bay City 

Plant, and the municipal water supply for Bay City. The shortest distance from this group of 

facilities to STP is approximately 5 mi (8 km) (NRC 2011b).

Groundwater used at STP, Units 1 and 2, is from the Deep Chicot Aquifer. Public water 

supplies and other large-scale industrial users also draw from this aquifer. As noted in 

Section 4.4.2.1, there has been a regional drawdown in the Deep Aquifer in the vicinity of the 

STP site. By 1980, a regional drawdown of approximately 35 ft (11 m) was attributed to 

groundwater development to the north of the STP site (STPNOC 2009a). Proposed STP, 

Units 3 and 4, would also use the groundwater from the production wells at the STP site. 

Groundwater use by STP, Units 1 and 2, is 768 gpm (2,910 L/min) for normal operations (see 

Section 2.1.7.2). Groundwater use by the proposed STP, Units 3 and 4, is 975 gpm 

(3,690 L/min) for normal operations. These rates represent 2.4 and 3.1 percent, respectively, of 

the annual rate of groundwater use permitted by the CPGCD in Matagorda County during the 

2008 to 2010 permit period (NRC 2011b). Based on the best available information, other than 

the proposed STP, Units 3 and 4, there are no other foreseeable nearby new projects with a 

substantial demand for groundwater. The aquifer drawdown projections from STP well pumping 

for selected distances are shown in Table 4–6 and discussed in Section 4.4.2.1. Potential 

impacts of drawdown from STP operations on other groundwater users, and from other users’ 

pumping on STP, would be minimal because the Deep Chicot Aquifer remains confined, and 

changes in pumping lift over the 20-year renewal period would not be substantial.

Because of higher groundwater use in the past, subsidence has been an issue in the STP 

region. The USGS (Ryder and Ardis 2002) has described subsidence in Matagorda County as 

less than 1 ft (0.3 m) since 1900 over most of the region, with somewhat higher subsidence of 

1.5 ft (0.46 m) noted in western Matagorda County. STPNOC has observed a subsidence rate 

of less than 0.1 in. (0.25 cm) to about 0.2 in. (0.50 cm) per year during construction and through 

STP, Units 1 and 2, operations in 1993 (STPNOC 2008b). The updated final safety analysis 

report (UFSAR) for STP, Units 1 and 2, projected regional subsidence from 1973 through 2020 

to be between 2.5 and 3 ft (0.76 and 0.9 m) based on a projected regional groundwater decline 

of 87 ft (26.5 m) and subsidence coefficients derived from regional observations 

(STPNOC 2009c). To minimize the potential for subsidence, STPNOC spaced its main 

production wells (i.e., wells 5, 6, and 7) over 5,000 ft (1,520 m) apart and distributes the 

pumping rates among them. All groundwater users in Matagorda County operate their wells 

under the rules of the CPGCD (2009). The purpose of the CPGCD is to provide for conserving, 

preserving, protecting, and recharging the groundwater to control subsidence and prevent the 

waste and pollution of the groundwater resource. Groundwater use under the rules of the 

CPGCD minimizes the potential for excessive drawdown, saltwater intrusion, or land 

subsidence impacts to arise and affect neighboring groundwater users (CPGCD 2009). Current 

observations of drawdown are consistent with the drawdown projected in the UFSAR for STP, 

Units 1 and 2, and subsidence projections are consistent with observations. These potential 

impacts are greatest on site where they are monitored. As noted in Section 4.3.2.1, drawdown 

at STP production wells is currently in equilibrium with the surrounding groundwater aquifer, and 

continued operation of STP wells for an additional 20 years beyond the current license would 
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increase drawdown by less than 1 ft (0.3 m). Additional subsidence resulting from this change 

in drawdown during the license renewal term would be minimal.

Operation of STP, Units 1 and 2, does not adversely affect groundwater quality in the Deep 

Chicot Aquifer because of the low-conductivity layer between 100 and 150 ft (30 and 46 m) thick 

that separates and isolates the Shallow Chicot Aquifer from the Deep Chicot Aquifer. Similarly, 

because of the hydraulic isolation of the Deep Chicot Aquifer from the Shallow Chicot Aquifer 

and any releases at the land surface, other nearby groundwater users are also not adversely 

affecting groundwater quality in the Deep Chicot Aquifer. Groundwater drawdown at the STP 

production wells is great enough to reverse the regional gradient and draw groundwater in the 

Deep Chicot Aquifer from beneath the STP site into the production wells. Thus, if any releases 

from the plant were to move from the Shallow to the Deep Chicot Aquifer, the contamination 

would likely be drawn to and intercepted by STP groundwater production wells (NRC 2011b).

With regard to the Deep Chicot Aquifer, because of the reasons presented above, the NRC staff 

concludes that cumulative impacts on groundwater use and quality during the license renewal 

term would be SMALL.

4.12.4 Aquatic Resources

This section addresses the direct and indirect effects of license renewal on aquatic resources 

when added to the aggregate effects of other past, present, and reasonably foreseeable future 

actions. The geographic area considered in this analysis includes the STP site and the portion 

of the lower Colorado River basin within influence of STP operations, including Matagorda Bay.

In agreement with NEPA guidance, the baseline is the condition of the resource without the 

action (i.e., under the no-action alternative). Under the no-action alternative, the plant would 

shut down, and the resource would conceptually return to its condition without the plant, which

is not necessarily the same as the condition before the plant was constructed. The baseline 

condition or benchmark for assessing cumulative impacts on aquatic resources takes into 

account the preoperational environment, as recommended by EPA (1999) for its review of 

NEPA documents:

Designating existing environmental conditions as a benchmark may focus the 

environmental impact assessment too narrowly, overlooking cumulative impacts 

of past and present actions or limiting assessment to the proposed action and 

future actions. For example, if the current environmental condition were to serve 

as the condition for assessing the impacts of relicensing a dam, the analysis 

would only identify the marginal environmental changes between the continued 

operation of the dam and the existing degraded state of the environment. In this 

hypothetical case, the affected environment has been seriously degraded for 

more than 50 years with accompanying declines in flows, reductions in fish 

stocks, habitat loss, and disruption of hydrologic functions. If the assessment 

took into account the full extent of continued impacts, the significance of the 

continued operation would more accurately express the state of the environment 

and thereby better predict the consequences of relicensing the dam.

Sections 2.2.5 and 2.2.7 of this SEIS present an overview of the history and factors that led to 

the current condition of the aquatic features on the STP site, the Colorado River, and Matagorda 

Bay. Since the 1920s, development and redirection of the lower Colorado River has affected 

the water quality, water chemistry, and aquatic resources. These alterations have increased the 

freshwater input to Matagorda Bay and marine and estuarine inputs to the lower Colorado River, 

resulting in a change in salinity. Anthropogenic activities has decreased available habitat for 

some species and increased available habitat for others. For example, construction and 
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development projects have reduced the area available for aquatic organisms to navigate 

through the Colorado River and Matagorda Bay due to erosion, habitat modification, and habitat 

fragmentation. Overall, species richness and diversity have increased in the lower Colorado 

River near STP (from the GIWW to navigation mile marker 8) based on surveys in 2007 to 2008 

compared to similar surveys in 1983 to 1984 (ENSR 2008b; NRC 1986, 2011b; 

STPNOC 2010b). The change in the aquatic community could be due to differences in study 

methods (e.g., differences in sampling protocol over time), environmental conditions 

(e.g., variance in weather conditions during the two sampling efforts), or from human activities 

(e.g., the river diversion projects that has increased the marine and estuarine flow into the lower 

Colorado River).

Many natural and anthropogenic activities can influence the current and future aquatic biota in 

the area surrounding STP. Potential biological stressors include continued entrainment, 

impingement, and potential heat shock from STP, Units 1 and 2 (if the license renewal is 

granted), as described in Section 4.5, construction and operation of STP, Units 3 and 4, other 

water use projects, urbanization, fishing, and GCC, as described below.

Construction and Operations of STP, Units 3 and 4. In 2007, STPNOC submitted an application 

to the NRC to construct and operate two additional nuclear reactors on the STP site, referred to 

in this SEIS as STP, Units 3 and 4. In 2011, NRC published its final EIS evaluating the 

environmental impacts of the proposed construction and operations of Units 3 and 4 

(NRC 2011b). This project would have overlapping impacts with the continued operations of 

Units 1 and 2. For example, all four units would draw water from the MCR, which need to be 

filled higher than current levels (STPNOC 2010c). STPNOC would draw the additional makeup 

water from the Colorado River through the RMPF. Species impinged and entrained would be 

similar to those impinged and entrained during operations of Units 1 and 2. Past impingement 

and entrainment studies and NRC evaluations of such studies concluded that impacts to the 

important species would be insignificant and minor, primarily because the density of organisms 

in the vicinity is rather low and the species are ubiquitous in the region (McAden 1984, 1985; 

NRC 1986, 2011b). Additionally, the design and operation of the RMPF minimize impacts on 

aquatic biota, as described in Section 4.5.2. Therefore, impacts from operation of the RMPF 

(impingement, entrainment, and entrapment) for four units are unlikely to destabilize aquatic 

resources in the lower Colorado River.

Operation of the four units would also affect aquatic resources in the MCR. Higher intake levels 

to provide cooling water for four units would increase impingement and entrainment at the 

CWISs in the MCR. The two discharges from the four units would increase the water 

temperature in the MCR. Aquatic organisms in the MCR would either avoid or acclimate to the 

new conditions. Because the aquatic community in the MCR is isolated from the onsite water 

bodies and the Colorado River, these impacts would not noticeably alter the aquatic resources 

within the geographic area of interest.

Operation of two additional units would increase the frequency and duration of discharges from 

the MCR into the Colorado River. STPNOC would manage discharges, as needed, based on 

water quality in the MCR and TPDES permit conditions (STPNOC 2010b). Chemical releases 

from discharging into the Colorado River are expected to be below the criteria for protection of 

aquatic life (TCEQ 2005). NRC (2011b) determined that under certain conditions, such as poor 

river water quality, the size and configuration of the thermal plume could impede passage of the 

aquatic organisms in the Colorado River, including species that are of commercial and 

recreational importance and species that are Federally managed and have designated EFH. 

NRC (2011b) concluded that the foraging behavior and high fecundity of such aquatic 
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organisms suggest that the effects from the thermal plume would not noticeably alter or 

destabilize the populations or aquatic community in the lower Colorado River.

NRC (2011b) concluded that the impacts to aquatic resources from other construction and 

operational activities of all four units would not noticeably alter or destabilize aquatic resources. 

These impacts include additional seepage from the MCR that could influence flow to Little 

Robbins Slough and wetlands, increased non-permeable surfaces (e.g., parking lots and 

buildings) that would change the flow of stormwater into the drainages on site, maintenance 

dredging in the Colorado River, shoreline restoration activities along the Colorado River, and 

disturbances from vessel traffic to marine mammals (NRC 2011b).

Other Water Use Projects. Future projects near STP that would withdraw or redirect significant 

quantities of the Colorado River include the proposed LCRA–SAWS Project, WSEC, and 

municipal use (TWDB 2006; WSEC 2011).

The LCRA–SAWS Project is projected to generate 150,000 ac-ft of new water supplies by 2060 

through conjunctive use of groundwater from the Gulf Coast Aquifer and surface water supplies 

from the Colorado River (TWDB 2006). LCRA–SAWS (2009) will evaluate impacts to aquatic 

habitat in the Colorado River with and without the proposed project. WSEC, a proposed 

coal-fired generating plant, would withdraw approximately 22,000 ac-ft per year of water from 

the lower Colorado River (WSEC 2011). LCRA included water use from WSEC growth in its 

water supply resource plan for Region K, Matagorda County. Other sources of water use 

included in water supply estimates include increases in municipal use due to population, 

manufacturing, mining, irrigation, transfer of water via the proposed Mary Rhodes Pipeline II, 

and other categories (TWBD 2006). From 2010 to 2040, the plan estimates an annual increase 

of 12 percent without the WSEC Project and 80 percent with the WSEC Project (LCRA 2008).

These projects have the potential to change the freshwater contribution in the river within the 

vicinity of STP by redirecting the flow or by withdrawing a significant amount of freshwater. 

Changes in flow of saltwater into the river could change the habitat (or salinity) for many 

species. In response, estuarine-marine species would likely become more abundant if the 

salinity increases whereas freshwater species would likely become more abundant if the salinity 

decreases. The Colorado River diversion project, which increased the flow between the 

Colorado River and Matagorda Bay, resulting in an increase in salinity near the STP site, likely 

influenced the shift in aquatic communities near STP towards estuarine-marine species 

(ENSR 2008b; NRC 1975, 1986, 2011b).

Urbanization and Development. Residential or industrial development in the vicinity of STP site 

can affect aquatic resources. Increased urbanization and population growth, while projected to 

be low in comparison to other locations in Texas (NRC 2011b), would still lead to increased 

development along the shores of the Colorado River that can contribute to cumulative impacts 

in the lower Colorado River basin through habitat loss and nonpoint source pollution. Future 

activities could lead to increased water needs, nonpoint and point source water pollution, vessel 

traffic on the waterways, and maintenance dredging.

Proposed future power generation facilities to support increased energy usage, including WSEC 

and the Victoria County Station, may require the development of new transmission systems in 

the geographic area of interest. The WSEC may be required to add additional transmission 

capabilities within the vicinity for its power transmission, but that information is currently not 

available to evaluate (WSEC 2011). If WSEC or Victoria County Station build new transmission 

corridors, they would likely have a minor effect on aquatic species assuming the owners 

consider aquatic resource when routing transmission lines and employ best management 

practices (BMPs) during construction and maintenance activities.
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STPNOC would use existing transmission corridors to support power transmission from 

proposed Units 3 and 4 and during the period of extended operations for Units 1 and 2. 

STPNOC (2010b, 2010c) would employ vegetation maintenance and control along existing and 

future corridors, which would not be expected to increase and contribute to cumulative effects 

(NRC 2011b).

Fishing. Commercial and recreational fishing in the Colorado River and Matagorda Bay would 

likely continue to increase in the future. The region is recognized for recreational fishing of 

many species, and fishing would likely increase with increased urbanization in the vicinity. 

Matagorda Bay is one of the recognized regions in Texas for commercial fishing, primarily 

associated with the shrimp industry (TPWD 2002), although these fisheries are not significant 

contributors to employment in the region (NRC 2011b). In efforts to improve the fisheries in the 

area, TPWD has designated the “most eastern half of the eastern arm of Matagorda Bay” as a 

finfish and shellfish nursery, closing the area to commercial fishing and commercial harvesting 

of oysters (LCRA et al. 2006). A freshwater inflow needs study for Matagorda Bay has identified 

several alternatives associated with water management strategies designed to improve 

commercial fishing opportunities (LCRA et al. 2006). If management strategies do not improve 

sustainability of fisheries, increased fishing pressures could result in overall decreased 

biological productivity for the Colorado River and Matagorda Bay.

Climate Change. In addition to direct anthropogenic activities, GCC could impose additional 

stressors on aquatic communities. The presence of natural environmental stressors (e.g., shortor long-term changes in precipitation or temperature) would contribute to the cumulative 

environmental impacts to the Colorado River and Matagorda Bay. GCC could lead to 

decreased precipitation, increased sea levels, varying freshwater inflow, increased 

temperatures, increased storm surges, greater intensity of coastal storms, and increased 

nonpoint source pollution from runoff during these storms (GCRP 2009; Montagna et al. 1995; 

Nielsen-Gammon 1995). Such changes could directly affect habitat for aquatic communities by 

altering the flow of freshwater, water quality, salinity, and dissolved oxygen levels. Habitat 

alterations could result in changes to community structure, species abundance, and species 

diversity. These kinds of changes occurred in the vicinity of STP with the diversion of the 

Colorado River into the Gulf and Matagorda Bay since the 1920s (NRC 2011b).

GCC could also slow efforts to restore nursery habitats in Matagorda Bay. The Colorado River 

diversion project increased the flow of freshwater into the bay in an effort to improve habitat for 

wetlands, oyster reefs, and other nursery grounds (USACE 2009). However, LCRA et al. (2006) 

indicated slower than expected results and showed that more freshwater inflow into the bay is 

needed to increase biological productivity in the bay. The effects of rising sea level, which 

would increase salinity in the bay, would likely be counterproductive to the current efforts to 

increase freshwater flows into the Bay. Changes in water quality in Matagorda Bay and the 

lower Colorado River could create areas that are hypoxic (low in dissolved oxygen) and lead to 

further stress on aquatic communities (Montagna et al. 1995). These stressors would result in 

shifts in species ranges, habitats, and migratory behaviors and also alter ecosystem processes 

(GCRP 2009).

Conclusion. Past, present and reasonably foreseeable future activities exist in the geographic 

area of interest that could contribute to cumulative effects to aquatic ecological resources. 

Future development of industries that compete for water in the Colorado River, such as WSEC, 

as well as management of water budgets across the State of Texas through diversion projects 

like the LCRA–SAWS Project and the Mary Rhodes Pipeline Phase II Project, would likely affect 

aquatic resources in the lower Colorado River. Such actions in combination with other direct 

and indirect anthropogenic and natural environmental stressors, including GCC, would 
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cumulatively lead to effects on the aquatic communities that would noticeably alter important 

attributes such as species range, habitat availability, ecosystem processes, migratory corridors 

and behavior, species diversity, and species abundance. The NRC staff concludes that 

cumulative impacts from past, present, and reasonably foreseeable actions to aquatic resources 

in the geographic area of interest would be MODERATE. 

4.12.5 Terrestrial Resources

Historic Conditions. Section 2.6 discusses the ecoregion in which the STP site lies—the 

Western Gulf Coastal Plain—which is dominated by tallgrass and shortgrass prairie. 

Historically, these prairies covered about 6.5 million ac (2.6 million ha) within Texas. During the 

past century, urban and industrial development and agricultural expansions have fragmented 

the natural habitat. In the late 1800s, ranchers introduced large numbers of cattle to the region. 

Livestock grazing continues to be a major land use, but the majority of land has been altered for 

cultivation of rice, sugarcane, forage, and grain. By the 1980s, Diamond and Smeins (1984) 

estimated that less than one percent of Texas’s native coastal prairie grasslands remained in a 

relatively pristine state.

The Texas Gulf coasts historically contained abundant and diverse wetlands. Approximately 

30 percent of the coastal prairies along the Texas Gulf coasts were once wetlands 

(TPWD 2010). Human activities, including landscape alteration for agricultural, industrial, or 

urban uses, continue to significantly threaten remaining wetland habitats (TPWD 2005). In 

addition, decreased precipitation, sea-level rise, more frequent high-intensity storm surges, and 

increased temperatures resulting from GCC have contributed to wetland losses (GCRP 2009). 

Nonetheless, rice fields, prairie wetlands, and coastal marshes continue to provide important 

habitat for waterfowl and many other wildlife species. TPWD (2005) identified the Gulf coasts 

and associated grassland prairies, wetlands, marshes, and agriculture as one of the most 

important wintering areas for North America’s waterfowl populations.

On the immediate site, STPNOC cleared land for, built, and filled the 7,000-ac (2,800-ha) MCR 

and cleared an additional 300 ac (120 ha) for the facility’s buildings, parking lots, roads, and 

other infrastructure. 

In the region surrounding the STP site, construction of many industrial facilities and wastewater 

treatment plants have resulted in the loss of terrestrial habitat. These facilities include:

• the Formosa Plastics Corporation plant,

• the Texas Liquid Fertilizer Company,

• the Alcoa aluminum plant,

• the Equistar Chemical LP’s Matagorda facility, and

• the OXEA Corporation’s chemical plant.

Other Projects. Many projects near the STP site could affect the terrestrial environment in the 

future. These projects are discussed in this section.

Chemicals Inc. has a specialty chemical plant near STP. The plant’s 107.5-ac (44-ha) site is 

located about 5 mi (8 km) south of Bay City (Chemicals Inc. 2011). 

About 5 mi (8 km) northeast of the STP site, a 1,200-ac (490-ha) tract of land is the site for the 

WSEC, a 1,320-net-mW coal and petroleum coke plant (MCEDC 2011). The TCEQ granted the 

project its air quality permit in September 2010. The status of the facility’s wastewater permit is 
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uncertain. Coal-fired plants are a major source of air pollution in the U.S. because they release 

sulfur dioxide, nitrogen oxides, mercury, carbon dioxide, and particulates. Nitrous oxides and 

sulfur dioxides combine with water to form acid rain, which can lead to erosion and changes in 

soil pH levels. Mercury deposits onto soil and surface water, which may then be taken up by 

terrestrial and aquatic plant or animal species and poses the risk of bioaccumulation.

In September 2007, STPNOC submitted COL applications to the NRC for two new nuclear units 

on the STP site. If approved, STPNOC would construct the new units adjacent to the currently 

operating Units 1 and 2. As a result, about 540 ac (220 ha) would be disturbed. Of this, the 

new reactors, the associated buildings and infrastructure, and a new heavy haul road would 

occupy 300 ac (120 ha), and the remaining 240 ac (100 ha) would only be temporarily disturbed 

for temporary buildings, construction equipment storage, and material laydown (NRC 2011b). 

The majority of land that would be disturbed is currently maintained or mowed grasslands, 

shrub-scrub habitat, or used for existing industrial activities. The new units would require 

additional transmission lines to transfer power to the regional electric grid. However, STPNOC 

would not create any new or expand any existing transmission line corridors (NRC 2011b). In 

the NRC’s EIS regarding the proposed new STP units, the NRC (2011b) concluded that impacts 

to the terrestrial environment would be SMALL for this proposed action.

Development of the proposed Mary Rhodes Pipeline Phase II Project would likely also 

contribute to regional habitat loss and fragmentation. Potential cumulative impacts resulting 

from construction and operation of the proposed water transport line would be similar to those 

impacts from constructing and maintaining new transmission line corridors and include habitat 

fragmentation, creation of early successional habitat, and displacement of certain wildlife 

species.

For projects listed above, construction and operation would impact wildlife by increasing noise 

and traffic, which could alter behavior or cause a shift in habitat use in undisturbed land 

bordering construction areas. Birds in the immediate area would be more likely collide with tall 

structures and construction equipment. However, construction impacts would be short-term and 

relatively minor. Hence, the impacts would not destabilize the environment.

Urbanization and Habitat Fragmentation. As the region surrounding the STP site becomes 

more developed, habitat fragmentation will increase. Species that require larger ranges, 

especially predators, will likely suffer reductions in their populations. In contrast, herbivores will 

experience less predation pressure, and their populations are likely to increase. Edge species 

will likely benefit from the fragmentation, while species that require interior forest or swamp 

habitat will likely suffer. The transmission line corridors established for STP transmission lines 

represent habitat fragmentation, though many of these corridors pass through cultivated land 

that has already been converted from its native habitat or shrub-scrub habitat, which was 

minimally altered during transmission line construction. Habitat fragmentation of surrounding 

areas may increase the value of the network of wetlands within the Texas Prairie Wetlands 

Project—110 ac of which is set aside on the STP site—because this land will not experience 

fragmentation or other human-induced impacts.

Parks and Wildlife Preserves. The FWS and State have set many lands in the STP region aside 

as parks, preserves, or management areas. These include:

• Brazos Bend State Park, 

• Mad Island Marsh Preserve, 

• Mad Island Wildlife Management Area,
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• Big Boggy National Wildlife Refuge, and 

• the Texas Prairie Wetland Project, for which 110 ac (45 ha) on the STP site is 

set aside.

Section 2.2.6 of this SEIS describes these parks and preserves in more detail. These areas will 

continue to provide valuable habitat to native wildlife, migratory birds, and native prairie and 

marsh vegetation. Both the National Wildlife Refuge Network and the Texas Prairie Wetland 

Project are ongoing efforts. In the future, FWS and Ducks Unlimited will continue to acquire 

lands for these projects.

Conclusion. The NRC staff examined the cumulative effects of the construction of STP, 

neighboring energy projects, continued urbanization and habitat fragmentation, and nearby 

parks and wildlife preserves. The NRC staff concludes that the minimal terrestrial impacts on 

the continued STP operations would not contribute to the overall decline in the condition of 

terrestrial resources. The NRC staff believes that the cumulative impacts of other and future 

actions during the term of license renewal on terrestrial habitat and associated species, when 

added to past, present, and reasonably foreseeable future actions, would be MODERATE.

4.12.6 Human Health

Radiological Impacts. The radiological dose limits for protection of the public and workers have 

been developed by the NRC and EPA to address the cumulative impact of acute and long-term 

exposure to radiation and radioactive material. These dose limits are codified in 

10 CFR Part 20 and 40 CFR Part 190. For the purpose of this analysis, the area within a 50-mi 

(80.4-km) radius of STP was included. The REMP conducted by STPNOC in the vicinity of the 

STP site measures radiation and radioactive materials from all sources (i.e., hospitals and other 

licensed users of radioactive material); therefore, the monitoring program measures cumulative 

radiological impacts. Within the 50-mi (80-km) radius of the STP site, there are currently no 

other nuclear power reactors or uranium fuel cycle facilities.

Radioactive effluent and environmental monitoring data for the 5-year period from 2006 to 2010 

and, for this final SEIS, data from the 2012 reports were reviewed as part of the cumulative 

impacts assessment. In Section 4.8.1 of this SEIS, the NRC staff concluded that impacts of 

radiation exposure to the public and workers (occupational) from operation of STP during the 

renewal term are SMALL. The NRC and the State of Texas would regulate any future actions in 

the vicinity of the STP site that could contribute to cumulative radiological impacts.

As stated in its ER, the applicant stores its spent nuclear fuel in its spent fuel pool. The 

applicant estimates that there is adequate capacity in its spent fuel pool to store spent fuel until 

2025. For reactor operations past that date, STPNOC plans to install a dry fuel storage system 

at the STP site for the storage of its spent fuel. The installation and monitoring of this facility will 

be governed by NRC requirements in 10 CFR Part 72, “Licensing Requirements for the 

Independent Storage of Spent Nuclear Fuel, High-Level Radioactive Waste, and 

Reactor-Related Greater Than Class C Waste.” Radiation from this projected storage facility as 

well as from the operation of STP, Units 1 and 2, are required to be within the radiation dose 

limits in 10 CFR Part 20, 40 CFR Part 190, and 10 CFR Part 72. The NRC performs periodic 

inspections of every licensed dry fuel storage facility to verify its compliance with all licensing 

and regulatory requirements. Currently, the applicant has not submitted an application to the 

NRC for the dry fuel storage system, so no further information is available.

In September 2007, STPNOC applied to the NRC for a COL pursuant to the requirements of 

10 CFR Part 52 for the construction and operation of two additional reactors at the STP site. 
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STPNOC submitted information on the site and surrounding area to NRC in its application for 

the COL. The NRC reviewed the COL application and issued the final EIS (NRC 2011b), which 

analyzed the impacts on the surrounding communities and natural resources to determine if the 

STP site is suitable to support two additional reactor units (proposed Units 3 and 4). The NRC 

also evaluated the cumulative impacts of the operation of four reactor units and considered the 

possible life extension of STP, Units 1 and 2, for 20 years. In the final EIS, the NRC staff 

concludes that cumulative radiological impacts would be SMALL.

In addition, pursuant to 10 CFR Part 20 and 40 CFR Part 190, the cumulative radiological 

impacts from STP, Units 1 and 2, the possible projected dry fuel storage system, and two 

additional reactor units are required to meet the acceptable radiation dose limits (protecting 

human health) specified in these regulations. EPA regulation (40 CFR 190) limits the total dose 

to an offsite individual near STP from “all uranium fuel cycle facilities and all pathways,” located 

at STP. Furthermore, the STP REMP would monitor the buildup of radioactivity in the 

environment to effectively ensure that the levels remain acceptable. Based on this information, 

the staff concludes that cumulative radiological impacts would be SMALL.

Electromagnetic Fields Impacts. For electromagnetic fields impacts on human health, the staff 

determined that not all of the STP transmission lines are operating within design specifications 

and meet current NESC criteria. In Section 4.8.4, the NRC staff determined that the potential 

impacts from STP transmission lines were SMALL to MODERATE. However, STP addressed 

the issue of acute shock by providing the staff with potential actions it is considering to mitigate 

the impacts. Therefore, the staff concludes that the transmission lines are not expected to 

significantly affect the overall potential for electric shock from induced currents within the 

analyzed area of interest. 

With respect to the effects of chronic exposure to ELF-EMF, as discussed in Section 4.8.5, the 

GEIS finding of “uncertain” is appropriate to STP. 

For the reasons listed above, the staff concludes that the cumulative impacts of continued 

operation of the STP transmission lines and other transmission lines in the affected area would 

be SMALL to MODERATE.

Microorganisms Impacts. In the environmental review for the proposed Units 3 and 4, the NRC 

staff determined that other projects (e.g., the Mary Rhodes Pipeline Phase II Project) would use 

or divert river water upstream of STP. These projects, depending on the magnitude and without 

mitigation measures, could reduce freshwater river flow and increase the ambient river water 

temperature (Neuces River Authority 2001; TWDB 2006b; WSEC 2009). Therefore, this 

cumulative effect on Colorado River conditions could be favorable for an increased presence of 

thermophilic microorganisms and, subsequently, increase the risk of public exposure to potential 

harmful microorganisms (thermophilic). However, based on past data on waterborne diseases 

from recreational water activities in Texas and the discharging limits on STP, cumulative 

impacts to human health due to exposure to microorganisms in the Colorado River would likely 

be minimal (CDC 2009; TDSHS 2010). Hence, the staff concludes that cumulative impacts to 

human health due to exposure to microorganisms in the Colorado River would be SMALL.

4.12.7 Socioeconomics

This section addresses socioeconomic factors that have the potential to be directly or indirectly 

affected by changes in operations at STP, Units 1 and 2, in addition to the aggregate effects of 

other past, present, and reasonably foreseeable future actions. The primary geographic area of 

interest considered in this cumulative analysis is Brazoria and Matagorda Counties, where 

approximately 84 percent of STP employees reside (see Table 2–12). This is where the 
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economy, tax base, and infrastructure would most likely be affected since STP workers and 

their families reside, spend their income, and use their benefits within these counties.

As discussed in Section 4.9 of this SEIS, continued operation of STP, Units 1 and 2, during the 

license renewal term would have no impact on socioeconomic conditions in the region beyond 

those already experienced. Accordingly, the NRC concluded that the impacts would be SMALL. 

Since STPNOC has no plans to hire additional workers during the license renewal term, overall 

expenditures and employment levels at STP, Units 1 and 2, would remain relatively unchanged 

with no additional demand for permanent housing and public services. In addition, since 

employment levels and tax payments would not change, there would be no population or tax 

revenue-related land use impacts. Based on this information and other information presented in 

Chapter 4 of this SEIS, there would be no additional contributory effect on socioeconomic 

conditions in the future from the continued operation of STP, Units 1 and 2, during the license 

renewal term beyond what is currently being experienced. The only cumulative contributory 

effects would come from the other reasonably foreseeable future planned activities at STP, such 

as the construction and operation of Units 3 and 4. 

The NRC completed an environmental review for the construction and operation of STP, Units 3 

and 4 (STPNOC 2011b). The potential socioeconomic impacts of the construction and 

operation of the proposed Units 3 and 4, in addition to the contributory effects of the continued 

operations of Units 1 and 2, are addressed in the Final EIS (NUREG-1937, Environmental 

Impact Statement for Combined Licenses (COLs) for South Texas Project Electric Generating 

Station, Units 3 and 4). The NRC concluded that the impacts would be both adverse and 

beneficial and could range from SMALL to LARGE in the immediate vicinity of STP. 

Therefore, the cumulative impact of the continued operation of STP, Units 1 and 2, when 

combined with the construction and operation of Units 3 and 4 would be SMALL to LARGE. 

There would be a major increase in the demand for temporary (rental) housing and public and 

business services in the vicinity of the STP site by thousands of construction workers during the 

years of construction. In addition, during periods of peak construction, there would be a major 

increase in the volume of construction vehicles and commuter worker traffic, especially during 

shift changes, on roads in the immediate vicinity of the STP site. Impacts would also occur to 

local economies in the immediate vicinity of STP due to increased sales, use, and property, and 

corporate taxes attributable to construction and operation of STP, Units 3 and 4. There would 

be a noticeable increase in the demand for permanent housing and public services, such as 

schools, police and fire, and public water and electric services by workers and their families 

during the years of power plant operations. In addition, there would be a noticeable increase in 

the number of commuter vehicles during shift changes and refueling outages on roads in the 

immediate vicinity of the STP site. The specific impact of this action will also depend on the 

final design, characteristics, and construction practices that would be used by STPNOC and its

contractors (STPNOC 2011b). 

Environmental Justice. The environmental justice cumulative impact analysis assesses the 

potential for disproportionately high and adverse human health and environmental effects on 

minority and low-income populations that could result from past, present, and reasonably 

foreseeable future actions including STP operations during the renewal term. Adverse health 

effects are measured in terms of the risk and rate of fatal or nonfatal adverse impacts on human 

health. Disproportionately high and adverse human health effects occur when the risk or rate of 

exposure to an environmental hazard for a minority or low-income population is significant and 

exceeds the risk or exposure rate for the general population or for another appropriate 

comparison group. Disproportionately high environmental effects refer to impacts or risk of 

impact on the natural or physical environment in a minority or low-income community that are 
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significant and appreciably exceed the environmental impact on the larger community. Such 

effects may include biological, cultural, economic, or social impacts. Some of these potential 

effects have been identified in resource areas presented in Chapter 4 of this SEIS. Minority and 

low-income populations are subsets of the general public residing in the area, and all would be 

exposed to the same hazards generated from STP operations. 

Based on the information discussed in this section, and the analysis of human health and 

environmental impacts presented in Chapters 4 and 5, it is unlikely there would be any 

disproportionately high and adverse contributory effect on minority and low-income populations 

from the continued operation of STP and other reasonably foreseeable future actions during the 

license renewal term. Therefore, the cumulative impacts on environmental justice during the 

license renewal term would be SMALL.

4.12.8 Historic and Archaeological Resources

This section addresses the direct and indirect effects of license renewal on historic and cultural 

resources when added to the aggregate effects of other past, present, and reasonably 

foreseeable future actions. The geographic area considered in this analysis is the APE 

associated with the proposed undertaking, as described in Section 2.2.9. 

Before construction of STP, the area was largely undisturbed and contained archaeological 

sites. In the early 1970s, the Texas Archaeological Survey conducted cultural resources 

investigations of the STP site and surrounding area. The investigations included a literature 

review, a pedestrian survey, and limited subsurface testing (NRC 2011b; 

STPNOC 2010b, 2010c). The construction of STP was completed in the 1980s, and much of 

the site had been heavily disturbed by construction activities including the construction of the 

MCR. Section 2.2.10 presents an overview of the existing historic and archaeological resources 

located on the STP site. As described in Section 4.9.6, no cultural resources would be affected 

by relicensing activities associated with the STP site. 

Past land development has resulted in impacts on, and the loss of cultural resources near and 

at, the STP site. The impacts from other past, present, and reasonably foreseeable projects 

were reviewed to analyze overlapping impacts that might affect cultural resources. Direct 

impacts would occur if archaeological sites in the APE are physically removed or disturbed. The 

following projects are located within the geographic area considered for cumulative impacts:

• construction and operation of STP, Units 3 and 4,

• transmission lines, and

• future urbanization.

Construction and operation of STP, Units 3 and 4, transmission lines, and future urbanization 

have the potential to result in impacts on cultural resources through inadvertent discovery during 

ground-disturbing activities. However, based on the best available information, there are no 

known historic or archaeological resources on the STP site. In addition, STPNOC has 

environmental compliance procedures in place for cultural resource protection and inadvertent 

discovery and has stated the construction and operation activities would not affect the 

unrecorded gravesite on the STP site (STPNOC 2011g). Future urbanization near STP would 

be required to comply with applicable State and Federal laws regarding protection of cultural 

and archaeological resources, and any impacts would be mitigated accordingly.

Based on this information, the NRC staff finds that the continued operation of STP during the 

license renewal term would not incrementally contribute to cumulative impacts on historic and 
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archaeological resources within STP and in the surrounding area. Therefore, the cumulative 

impacts on historic and archaeological resources during the license renewal term would be 

SMALL. 

4.12.9 Summary of Cumulative Impacts

The staff considered the potential impacts resulting from the operation of STP during the period 

of extended operation and other past, present, and reasonably foreseeable future actions near 

STP. The preliminary determination is that the potential cumulative impacts would range from 

SMALL to MODERATE, depending on the resource. Table 4–17 summarizes the cumulative 

impacts on resources areas.

Table 4–17. Summary of Cumulative Impacts on Resource Areas

Resource Area Cumulative Impact

Air quality

The NRC staff examined the cumulative effects of the continued operation of 

STP, Units 1 and 2, the construction and operation of STP, Units 3 and 4, and the 

construction and operation of the nearby WSEC coal plant. The cumulative 

impacts on criteria pollutants from emissions of effluents from the STP site and 

the WSEC would be noticeable (but not destabilizing), principally as a result of 

the contribution of WSEC. In addition, cumulative effects of GCC would 

contribute to the degradation of air quality resources in the geographic areas of 

interest (i.e., AQCR). For these reasons, the cumulative impacts on air quality 

during the license renewal term would be MODERATE.

Water resources

Waters of the Colorado River Basin have been extensively used, and the region 

has surface water planning, allocation, and development systems in place to 

manage the use of its limited surface water resources. Nevertheless, because of 

the potential impacts associated with water use conflicts and maintenance of 

Colorado River flows to Matagorda Bay, the cumulative impacts on surface water 

resources during the license renewal term would be MODERATE.

Because of the effective controls by the CPGCD on water use and because the 

STP operational leaks have not substantially affected the groundwater quality 

within the STP site, the cumulative impacts on groundwater resources during the 

license renewal term would be SMALL. 

Aquatic ecology

Future development of industries that compete for water in the Colorado River, 

such as WSEC, as well as management of water budgets across the State of 

Texas through diversion projects like the LCRA–SAWS Project and the Mary 

Rhodes Pipeline Phase II Project would likely affect aquatic resources in the 

lower Colorado River. Such actions, in combination with other direct and indirect 

anthropogenic and natural environmental stressors—including GCC—would 

cumulatively lead to effects on the aquatic communities that would noticeably 

alter important attributes, such as species range, habitat availability, ecosystem 

processes, migratory corridors and behavior, species diversity, and species 

abundance. For these reasons, the cumulative impacts on aquatic ecology 

during the license renewal term would be MODERATE.
Environmental Impacts of Operation

4-76

Resource Area Cumulative Impact

Terrestrial ecology

The staff examined the cumulative effects of the construction at STP 

(e.g., proposed STP, Units 3 and 4), neighboring projects, continued urbanization 

and habitat fragmentation, and nearby parks and wildlife preserves. The staff 

concludes that the minimal terrestrial impacts on the continued STP operations 

would not contribute to the overall decline in the condition of terrestrial resources. 

For these reasons, the cumulative impacts on terrestrial ecology during the 

license renewal term would be MODERATE.

Human health

The radiological dose limits for protection of the public and workers have been 

developed by the NRC and EPA to address the cumulative impact of acute and 

long-term exposure to radiation and radioactive material. The NRC and the State 

of Texas would regulate any future actions in the vicinity of the STP site that 

could contribute to cumulative radiological impacts. In addition, the cumulative 

radiological impacts from operation of STP, Units 1 and 2, the projected dry fuel 

storage system, and two additional reactor units would be required to meet the 

radiation dose limits in 10 CFR Part 20 and 40 CFR Part 190. For these reasons, 

cumulative radiological impacts during the license renewal term would be SMALL.

Socioeconomics

As discussed in Section 4.12.7, if STPNOC receives NRC approval for the 

proposed new reactors and decides to construct one or two new nuclear power 

plants, the socioeconomic impacts of this action during construction could be 

SMALL to LARGE in the immediate vicinity of STP. The potential environmental 

impacts of the new reactor units are addressed in the final EIS (NUREG-1937)

prepared by the NRC staff for the construction and operation of the new reactors.

As discussed in Section 4.12.7, there would also be no disproportionately high 

and adverse impacts to minority and low-income populations from the continued 

operation of STP during the license renewal term. 

Historic & 

archaeological 

resources

As described in Sections 4.9.6 and 4.12.8, the continued operation of STP during 

the license renewal term would not incrementally contribute to the cumulative 

impacts on historic and archaeological resources within STP and in the 

surrounding area. Therefore, the cumulative impacts on historic and 

archaeological resources during the license renewal term would be SMALL.

4.13 References

10 CFR Part 20. Code of Federal Regulations, Title 10, Energy, Part 20, “Standards for 

protection against radiation.”

10 CFR Part 50. Code of Federal Regulations, Title 10, Energy, Part 50, “Domestic licensing of 

production and utilization facilities.”

10 CFR Part 51. Code of Federal Regulations, Title 10, Energy, Part 51, “Environmental 

protection regulations for domestic licensing and related regulatory functions.”

10 CFR Part 54. Code of Federal Regulations, Title 10, Energy, Part 54, “Requirements for 

renewal of operating licenses for nuclear power plants.”

36 CFR Part 60. Code of Federal Regulations, Title 36, Parks, Forests, and Public Property, 

Part 60, “National register of historic places.”
Environmental Impacts of Operation

4-77

36 CFR Part 800. Code of Federal Regulations, Title 36, Parks, Forests, and Public Property, 

Part 800, “Protection of historic properties.”

40 CFR Part 141. Code of Federal Regulations, Title 40, Protection of Environment, Part 141, 

“National primary drinking water regulations.”

40 CFR Part 190. Code of Federal Regulations, Title 40, Protection of Environment, Part 190, 

“Environmental radiation protection standards for nuclear power operations.”

50 CFR Part 402. Code of Federal Regulations, Title 50, Wildlife and Fisheries, Part 402, 

“Interagency Cooperation—Endangered Species Act of 1973, as Amended.”

59 FR 7629. Executive Order 12898. Federal actions to address environmental justice in 

minority populations and low-income populations. Federal Register 59(32):7629–7634. 

February 16, 1994.

66 FR 65274. U.S. Environmental Protection Agency. National pollutant discharge elimination 

system: regulations addressing cooling water intake structures for new facilities; final rule. 

Federal Register. December 18, 2001.

69 FR 41576. U.S. Environmental Protection Agency. National pollutant discharge elimination 

system—final regulations to establish requirements for cooling water intake structures at phase 

ii existing facilities; final rule. Federal Register. July 9, 2004.

69 FR 52040. U.S. Nuclear Regulatory Commission. Policy statement on the treatment of 

environmental justice matters in NRC regulatory and licensing actions. Federal Register. 

69(163):52040–52048. August 24, 2004.

71 FR 42298. U.S. Fish and Wildlife Service. Endangered and threatened wildlife and plants; 

establishment of a nonessential experimental population of northern aplomado falcons in New 

Mexico and Arizona. Federal Register 71(143):42298–42315.

76 FR 22174. U.S. Environmental Protection Agency. National pollutant discharge elimination 

system—cooling water intake structures at existing facilities and Phase I facilities. 

Federal Register. April 20, 2011.

78 FR 37282. U.S. Nuclear Regulatory Commission. Revisions to Environmental Review for 

Renewal of Nuclear Power Plant Operating Licenses. June 20, 2013. 

[AEC] U.S. Atomic Energy Commission. 1975. Final Environmental Statement Related to 

Operation of South Texas Project, Units 1 and 2. Houston Lighting & Power Company, City 

Public Service Board of San Antonio, Central Power and Light Company, City of Austin, Docket 

Nos. 50-498 and 50-499. Washington, DC: Directorate of Licensing. March 1975. ADAMS 

No. ML11172A200.

[CAPS] Missouri Census Data Center Circular Area Profiling System. Version 10C. Using Data 

from Summary File 1, 2010 Census Summary of Census Tracts in a 50-mi radius around the 

South Texas Project (28.97 Lat., -96.04Long.). March 2012.

[CEQ] Council on Environmental Quality. 1997a. Considering Cumulative Effects under the 

National Environmental Policy Act. Executive Office of the President, Washington, DC.

[CEQ] Council on Environmental Quality. 1997b. “Environmental Justice: Guidance Under the 

National Environmental Policy Act.” December 10, 1997. Available at 

<http://www.epa.gov/compliance/ej/resources/policy/ej_guidance_nepa_ceq1297.pdf> 

(accessed on April 6, 2012). ADAMS No. ML082520150.
Environmental Impacts of Operation

4-78

Chemicals Inc. 2011. “Growing in Matagorda County.” Available at 

<http://www.chemicalsinc.com/Bay%20City%20Fact%20Sheet%20Rev.pdf> (accessed 

27 September 2011).

City of Corpus Christi. 2009. Garwood Pipeline Project, Project Update 2009. Corpus Christi, 

TX: Water Department. October 2, 2009. Available at 

<http://www.cctexas.com/files/g17/GarwoodCouncilPresentation100209.pdf> (accessed 

31 August 2011).

City of Corpus Christi. 2011. Lake Texana & Mary Rhodes Pipeline II. Corpus Christi, TX: 

Water Department. Available at 

<http://cctexas.com/water/resources/MaryRhodesPipeline.html> (accessed 21 October 2011).

[USACE] U.S. Army Corps of Engineers. 2005. Galveston District Projects, Mouth of the 

Colorado River. Galveston, TX: U.S. Army Corps of Engineers, Galveston District. Available at 

<http://www/swg/usace.army.mil/items/coloradoriver/MOC/asp> (accessed 16 December 2009). 

ADAMS No. ML100601372.

[CPGCD] Coastal Plains Groundwater Conservation District. 2010. Rules of the Coastal Plains 

Groundwater Conservation District. Bay City, TX: CPGCD. February 4, 2010. Available at 

<http://www.coastalplainsgcd.com/> (accessed 21 October 2011).

[CPGCD] Coastal Plains Groundwater Conservation District. 2011. Operating Permit, Permit 

No. OP-04122805. Bay City, TX: CPGCD. February 24, 2011. ADAMS No. ML11256A058.

Diamond DD, Smeins FE. 1984. Remnant grassland vegetation and ecological affinities of the 

upper coastal prairie of Texas. Southwestern Naturalist 29(3):321–334.

Edward E. Johnson, Inc. 1966. Ground Water and Wells, A Reference Book for the Water-Well 

Industry. Saint Paul, MN: Edward E. Johnson, Inc.

[ENSR] ENSR Corporation. 2008a. Aquatic Ecology—Main Cooling Reservoir and Circulating 

Water Intake Structure Study, Unit 3 and 4 Licensing Project. Houston, TX. ADAMS 

No. ML090860875.

[ENSR] ENSR Corporation. 2008b. Aquatic Ecology—Colorado River Monitoring Report, 

Unit 3 and 4 Licensing Project. Houston, TX. ADAMS No. ML081750196.

[EPA] Environmental Protection Agency. 1977. Guidance for Evaluating the Adverse Impact of 

Cooling Water Intake Structures on Aquatic Environment. Washington, DC: Office of Water 

Enforcement, Permits Division. Section 316(b). May 1, 1977. 408 p.

[EPA] Environmental Protection Agency. 1985. Authorization to Discharge Under the National 

Pollutant Discharge Elimination System. Permit No. TX0064947.

[EPA] Environmental Protection Agency. 1998. Guidelines for Ecological Risk Assessment. 

Washington, DC: Risk Assessment Forum. EPA/630/R-95/002F. 

[EPA] Environmental Protection Agency. 1999. Consideration of Cumulative Impacts in EPA 

Review of NEPA Documents. Washington, DC: Office of Federal Activities (2252A). 

EPA-315-R-99-002. 

[FWS] U.S. Fish and Wildlife Service. 2011. Letter from AM Strand, Field Supervisor, to 

T Tran, Project Manager, NRC. Subject: Reply to request for species list for South Texas 

license renewal review. June 2, 2011. ADAMS No. ML11173A241.
Environmental Impacts of Operation

4-79

[FWS] U.S. Fish and Wildlife Service. 2011b. Letter from A. Strand, Field Supervisor, to 

T. Tran, Project Manager, NRC. Subject: Reply to request for species list for South Texas 

license renewal review. June 2, 2011. ADAMS No. ML11173A241.

[FWS] U.S. Fish and Wildlife Service. 2013d. E-mail from M Belton, Fish and Wildlife Biologist, 

FWS, to B Balsam, NRC. Subject: South Texas NRC informal consultation. March 14, 2013. 

ADAMS No. ML13077A117.

[FWS] U.S. Fish and Wildlife Service. 2012. “Species Status Codes.” Updated 

August 28, 2012. Available at <http://www.fws.gov/endangered/about/listing-status-codes.html> 

(accessed 15 April 2013).

Gulf of Mexico Fishery Management Council (GMFMC). 2004. Final Environmental Impact 

Statement for the Generic Amendment to the Following Fishery Management Plans of the Gulf 

of Mexico: Shrimp Fishery of the Gulf of Mexico, Red Drum Fishery of the Gulf of Mexico, Reef 

Fish Fishery of the Gulf of Mexico, Stone Crab Fishery of the Gulf of Mexico, Coral and Coral 

Reef Fishery of the Gulf of Mexico, Spiny Lobster Fishery of the Gulf of Mexico and South 

Atlantic; Coastal Migratory Pelagic Resources of the Gulf of Mexico and South Atlantic. Tampa, 

FL.

Institute of Electrical and Electronics Engineers, Inc. (IEEE). 2002. National Electrical Safety 

Code.

Intergovernmental Panel on Climate Change (IPCC). 2010. “IPCC Fourth Assessment Report: 

Working Group II Report—Impacts, Adaptation and Vulnerability.” Available at 

<http://www.ipcc.ch/ipccreports/ar4-wg2.htm> (accessed April 2012).

Karl, TR, et al., eds., Global Climate Change Impacts in the United States, New York, NY: U.S. 

Global Change Research Program, Cambridge University Press. Available at 

<http://downloads.globalchange.gov/usimpacts/pdfs/climate-impacts-report.pdf>. ADAMS 

No. ML100580077.

[LCRA] Lower Colorado River Authority. 2008. Water Supply Resource Plan: Water Demand 

Projections for Municipal and Industrial Needs. Austin, TX. Available at 

<http://www.lcra.org/library/media/public/docs/water/wsrp/WSRPDecember2008report.pdf> 

(accessed 13 June 2011).

[LCRA et al.] Lower Colorado River Authority (LCRA), Texas Commission on Environmental 

Quality (TCEQ), Texas Parks and Wildlife (TPWD), and Texas Water Development Board 

(TWDB). 2006. Matagorda Bay Freshwater Inflow Needs Study. August 2006. Available at 

<http://www.lcra.org/library/media/public/docs/water/wmp/FINS_Final_Report.pdf> (accessed 

31 August 2011).

[LCRA–SAWS] Lower Colorado River Authority and San Antonio Water System. 2009. 

“Colorado River Flow Relationships to Aquatic Habitat and State Threatened Species: Blue 

Sucker.” Available at 

<http://www.lcra.org/library/media/public/docs/lswp/scopes/BIO_AH_2009_Scope.pdf> 

(accessed 12 September 2011).

[LCRWPG] Lower Colorado River Water Planning Group. 2010. 2011 Region K Water Plan. 

Prepared for Texas Water Development Board. July 2010. Available at <

http://www.twdb.state.tx.us/waterplanning/rwp/plans/2011/K/Region_K_2011_RWPV1.pdf> 

(accessed 2 April 2013).
Environmental Impacts of Operation

4-80

[MACTEC] MACTEC Engineering and Consulting, Inc. 2009. Conceptual Site Model for Units 1 

and 2, Groundwater Protection Initiative, South Texas Project Electric Generating Station. 

Wadsworth, TX: MACTEC Engineering and Consulting, Inc. Revision 1. May 20, 2009. 

ADAMS No. ML11256A058.

McAden DC, Greene GN, Baker, WB. 1984. Colorado River Entrainment and Impingement 

Monitoring Program, Phase Two Studies. Ecology Division, Environmental Protection 

Department, Houston Lighting & Power Company. Report 1. October 1984. ADAMS 

No. ML11256A057.

McAden DC, Greene GN, Baker WB. 1985. Colorado River Entrainment and Impingement 

Monitoring Program, Phase Two Studies. Ecology Division, Environmental Protection 

Department, Houston Lighting & Power Company. Report 2. April 1985. ADAMS 

No. ML11256A057.

[MCEDC] Matagorda County Economic Development Corporation. 2011. “Matagorda County 

Project Status Updates for 19-Sept-2011.” Available at 

<http://www.mcedc.net/news.php?op=view&id=155> (accessed 27 September 2011).

Menzie C, Henning MH, Cura J, Finkelstein K, Gentile J, Maughan J, Mitchell D, Petron S, 

Potocki B, Svirsky S, Tyler P. 1996. Report of the Massachusetts Weight-of-Evidence 

Workshop: A weight-of-evidence approach for evaluating ecological risks. Human and 

Ecological Risk Assessment 2:227–304.

Montagna PA, Brenner J, Gibeaut J, Morehead S. 1995. Coastal Impacts. In: North GR, 

Schmandt J, Clarkson J, editors. The Impact of Global Warming on Texas. Austin, TX: 

University of Texas Press.

National Environmental Policy Act of 1969, as amended. 42 U.S.C. §4321, et seq.

National Historic Preservation Act of 1966, as amended. 16 U.S.C. §470, et seq.

[NEI] Nuclear Energy Institute. 2007. Industry Groundwater Protection Initiative—Final 

Guidance Document. Washington, DC: NEI. NEI 07-07. August 2007. ADAMS 

No. ML072600290.

[NIEHS] National Institute of Environmental Health Sciences. 1999. NIEHS Report on Health 

Effects from Exposure to Power-Line Frequency Electric and Magnetic Fields. Triangle Park, 

NC: NIEHS. Publication No. 99-4493. 80 p. Available at 

<http://www.niehs.nih.gov/about/materials/niehsreport.pdf>.

Nielsen-Gammon, JW. 1995. The Changing Climate of Texas. In: North GR, Schmandt J, 

Clarkson J, editors. The Impact of Global Warming on Texas. Austin, TX: University of Texas 

Press. 

[NMFS] National Marine Fisheries Service. 2010. Letter from M Croom, Assistant Regional 

Administrator for Habitat Conservation, to Johnson, Rulemaking and Directives Branch Chief, 

NRC. Subject: Concurrence with EFH assessment for STP, Units 3 and 4. ADAMS 

No. ML101190379.

[NMFS] National Marine Fisheries Service. 2011c. E-mail from T. Mincey, Program Analyst, to 

T. Tran, Project Manager, NRC. Subject: South Texas Project Federally listed species. March 

3, 2011. ADAMS No. ML110690848.

[NMFS] National Marine Fisheries Service. 2013. E-mail from N Bailey, ESA Consultant, 

NMFS, to B Balsam, NRC, regarding NRC’s request for concurrence on its ESA determinations 

for the proposed South Texas license renewal. January 29, 2013. ADAMS No. ML13036A306.
Environmental Impacts of Operation

4-81

[NMFS] National Marine Fisheries Service. 2013a. E-mail correspondence between B. Balsam, 

NRC, and N. Bailey, NMFS, regarding Section 7 consultation. January 29, 2013. ADAMS 

No. ML13036A306.

[NMFS] National Marine Fisheries Service. 2013b. E-mail from H. Young, NMFS, to B. Balsam, 

NRC, regarding EFH consultation with NRC for STP license renewal. March 1, 2013. ADAMS 

No. ML13063A071.

[NRC] U.S. Nuclear Regulatory Commission. 1975. Final Environmental Statement Related to 

the Proposed South Texas Project, Units 1 and 2. Washington, DC: NRC. NUREG-75/019.

[NRC] U.S. Nuclear Regulatory Commission. 1986. Final Environmental Statement Related to 

the Operation of South Texas Project, Units 1 and 2. Washington, DC: NRC. NUREG-1171.

[NRC] U.S. Nuclear Regulatory Commission. 1988. South Texas Project, Unit 1, Current 

Facility Operating License NPF-76. March 22, 1988. Revised August 30, 2012. ADAMS 

No. ML053140360.

[NRC] U.S. Nuclear Regulatory Commission. 1989. South Texas Project, Unit 2, Current 

Facility Operating License NPF-80. March 28, 1989. Revised August 14, 2012. ADAMS 

No. ML053140365.

[NRC] U.S. Nuclear Regulatory Commission. 1996. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. Washington, DC: NRC. NUREG-1437. May 1996. 

ADAMS Nos. ML040690705 and ML040690738.

[NRC] U.S. Nuclear Regulatory Commission. 1999. Section 6.3—Transportation, Table 9.1, 

Summary of findings on NEPA issues for license renewal of nuclear power plants. In: Generic 

Environmental Impact Statement for License Renewal of Nuclear Plants. Washington, DC: 

NRC. NUREG-1437, Volume 1, Addendum 1. August 1999. ADAMS No. ML040690720.

[NRC] U.S. Nuclear Regulatory Commission. 2010. Final Supplemental Environmental Impact 

Statement Regarding Indian Point Generating, Units 2 and 3. Washington, DC: Office of 

Nuclear Reactor Regulation. NUREG-1437, Supplement 38. 

[NRC] U.S. Nuclear Regulatory Commission. 2011a. E-mail from B Martin, THC, to TK O’Neil, 

PNNL. Subject: STP license renewal—SHPO meeting. May 2, 2011. ADAMS 

No. ML11259A029.

[NRC] U.S. Nuclear Regulatory Commission. 2011b. Environmental Impact Statement for 

Combined Licenses (COLs) for South Texas Project Electric Generating Station, Units 3 and 4. 

Washington, DC: NRC. NUREG-1937, Volumes 1 and 2. ADAMS Nos. ML11049A000 and 

ML11049A001.

[NRC] U.S. Nuclear Regulatory Commission. 2011c. Essential Fish Habitat Assessment for 

South Texas Project Electric Generating Station, Units 3 and 4. Washington, DC: NRC. Final 

Report. ADAMS No. ML11049A001.

[NRC] U.S. Nuclear Regulatory Commission. 2011d. Letter from BM Pham, NRC, to DL Klima, 

Advisory Council on Historic Preservation. Subject: South Texas Project, Units 1 and 2, license 

renewal application review. January 27, 2011. ADAMS No. ML110200002.

[NRC] U.S. Nuclear Regulatory Commission. 2011e. Letter from BM Pham, NRC, to M Wolfe, 

Texas Historical Commission. Subject: South Texas Project, Units 1 and 2, license renewal 

application review. February 17, 2011. ADAMS No. ML110190549.
Environmental Impacts of Operation

4-82

[NRC] U.S. Nuclear Regulatory Commission. 2011f. Letter from B Pham, Branch Chief, to 

M Orms, FWS. Subject: Request for concurrence on list of Federally protected species. 

February 16, 2011. ADAMS No. ML110190429.

[NRC] U.S. Nuclear Regulatory Commission. 2011g. Letter from T Tran, NRC, to GT Powell, 

STPNOC. Subject: Audit report regarding South Texas Project license renewal application—

cultural resources. July 18, 2011. ADAMS No. ML11173A304.

[NRC] U.S. Nuclear Regulatory Commission. 2011h. Letter from B Pham, Branch Chief, to 

D Bernhart, NMFS. Subject: Request for list of Federally protected species and important 

habitats within the area under evaluation for the STP license renewal. February 16, 2011. 

ADAMS No. ML110190434. 

[NRC] U.S. Nuclear Regulatory Commission (NRC). 2011i. Draft Supplemental Environmental 

Impact Statement Regarding Seabrook Station. NUREG-1437, Supplement 46. Office of 

Nuclear Reactor Regulation. Washington, DC. July 31, 2011. ADAMS No. ML11213A024.

[NRC] U.S. Nuclear Regulatory Commission. 2012a. E-mail from T. Tran, Project Manager, 

NRC, to L. Gaul, PhD, MPH, Epidemiologist, Emerging and Acute Infectious Diseases Branch, 

TDSHS. Subject: NEPA consultation, waterborne outbreak. May 4, 2012. ADAMS No. 

ML12128A061.

[NRC] U.S. Nuclear Regulatory Commission. 2012b. Letter from M. Wong, NRC, to M. Croom, 

NMFS. Subject: Request for essential fish habitat consultation for the proposed South Texas 

Project, Units 1 and 2, license renewal. December 11, 2012. ADAMS No. ML12285A197.

[NRC] U.S. Nuclear Regulatory Commission. 2012c. Letter from M. Wong, NRC, to B. Tuggle, 

FWS. Subject: Request for concurrence on the effects of the proposed South Texas Project 

license renewal on threatened and endangered species. December 10, 2012. ADAMS 

No. ML12285A415.

[NRC] U.S. Nuclear Regulatory Commission. 2012d. Letter from M. Wong, NRC, to 

R. Crabtree, NMFS. Subject: Request for concurrence on the effects of the proposed South 

Texas Project license renewal on threatened and endangered species. December 10, 2012. 

ADAMS No. ML12286A010.

[NRC] U.S. Nuclear Regulatory Commission. 2013a. E-mail from B Balsam, NRC, to M 

Belton, FWS. Subject: South Texas t-line maps for threatened and endangered species 

review. January 31, 2013. ADAMS No. ML13036A305.

[NRC] U.S. Nuclear Regulatory Commission. 2013b. Event Reporting Guidelines: 

10 CFR 50.72 and 50.73. Washington, DC: NRC. NUREG-1022. Revision 3. January 2013. 

107 p. ADAMS No. ML13032A220.

[NRC] U.S. Nuclear Regulatory Commission. 2013c. E-mail from B. Balsam, NRC, to 

R. Swafford, NMFS, regarding EFH consultation with NRC for STP license renewal. 

February 25, 2013. ADAMS No. ML13063A071.

[NRC] U.S. Nuclear Regulatory Commission. 2013d. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. Washington, DC: Office of Nuclear Reactor Regulation. 

NUREG-1437, Revision 1, Volumes 1, 2, and 3. June 2013. ADAMS Accession Nos. 

ML13106A241, ML13106A242, and ML13106A244. 
Environmental Impacts of Operation

4-83

Ryder PD, Ardis AF. 2002. Hydrology of the Texas Gulf Coast Aquifer Systems, Regional 

Aquifer-Systems Analysis-Gulf Coast Plain. Reston, VA: U.S. Geological Survey. U.S. 

Geological Survey Professional Paper 1416-E. 

[STPNOC] South Texas Project Nuclear Operating Company. 2007a. South Texas Project, 

Units 1 and 2. 2006 Annual Environmental and Annual Radiological Environmental Operating 

Reports. Wadsworth, TX. ADAMS No. ML071270211.

[STPNOC] South Texas Project Nuclear Operating Company. 2007b. South Texas Project, 

Units 1 and 2. Radioactive Effluent Release Report for 2006. Wadsworth, Texas. ADAMS 

No. ML071280681.

[STPNOC] South Texas Project Nuclear Operating Company. 2008a. Letter from G Gibson, 

STPNOC, to NRC Document Control Desk. Subject: Response to RAIs. July 15, 2008. 

ADAMS No. ML082040684.

[STPNOC] South Texas Project Nuclear Operating Company. 2008b. Letter from G Gibson, 

STPNOC, to NRC Document Control Desk. Subject: South Texas Project, Units 3 and 4, 

Docket Nos. 52-012 and 52-013, Response to RAIs. July 2, 2008. ADAMS No. ML081970465.

[STPNOC] South Texas Project Nuclear Operating Company. 2008c. Letter from S Head, 

STPNOC, to NRC Document Control Desk. Subject: Response to RAIs. December 18, 2008. 

ADAMS No. ML090860873.

[STPNOC] South Texas Project Nuclear Operating Company. 2008d. South Texas Project, 

Units 1 and 2. 2007 Annual Environmental and Annual Radiological Environmental Operating 

Reports. Wadsworth, TX. ADAMS No. ML081280093.

[STPNOC] South Texas Project Nuclear Operating Company (STPNOC). 2008e. South Texas 

Project, Units 1 and 2. Radioactive Effluent Release Report for 2007. Wadsworth, TX. ADAMS 

No. ML081300023.

[STPNOC] South Texas Project Nuclear Operating Company. 2009a. South Texas Project, 

Units 1 and 2. 2008 Annual Environmental and Annual Radiological Environmental Operating 

Reports. Wadsworth, TX. ADAMS No. ML091310066.

[STPNOC] South Texas Project Nuclear Operating Company. 2009b. South Texas Project, 

Units 1 and 2. Radioactive Effluent Release Report for 2008. Wadsworth, TX. ADAMS 

No. ML091200487.

[STPNOC] South Texas Project Nuclear Operating Company. 2009c. Updated Final Safety 

Analysis Report Units 1 and 2. Bay City, TX: STPEGS. Revision 15. April 29, 2010. ADAMS 

No. ML103220222.

[STPNOC] South Texas Project Nuclear Operating Company. 2009d. Water Conservation 

Plan, STP Nuclear Operating Company, South Texas Project Electric Generating Station, 

Certificate of Adjudication 14-5437 A. Revision 2. May 1, 2009. ADAMS No. ML11256A058.

[STPNOC] South Texas Project Nuclear Operating Company. 2010a. South Texas Project, 

Units 1 and 2. 2009 Annual Environmental and Annual Radiological Environmental Operating 

Reports. Wadsworth, TX. ADAMS No. ML101260530.

[STPNOC] South Texas Project Nuclear Operating Company. 2010b. South Texas Project, 

Units 1 and 2, License Renewal Application. Bay City, TX: STPNOC. “Environmental Report.” 

September 2010. ADAMS No. ML103010263.
Environmental Impacts of Operation

4-84

[STPNOC] South Texas Project Nuclear Operating Company. 2010c. South Texas Project, 

Units 3 and 4, License Renewal Application. Bay City, TX: STPNOC. Part 3, “Environmental 

Report.” Revision 4. ADAMS No. ML102860592.

[STPNOC] South Texas Project Nuclear Operating Company. 2010d. South Texas Project, 

Units 1 and 2. Radioactive Effluent Release Report for 2009. Wadsworth, TX. ADAMS 

No. ML101090091.

[STPNOC] South Texas Project Nuclear Operating Company. 2011a. South Texas Project, 

Units 1 and 2. 2010 Annual Environmental and Annual Radiological Environmental Operating 

Reports. Wadsworth, TX. ADAMS No. ML111250429.

[STPNOC] South Texas Project Nuclear Operating Company. 2011b. Letter from AW Harrison, 

Manager Licensing, to NRC Document Control Desk. Subject: Transmittal of documents to 

support review of the STP LRA. TAC Nos. ME 4938 and ME 5122. STP Letter 

No. NOC-AE-11002720. August 31, 2011. ADAMS Nos. ML11256A056 and ML11256A059. 

[STPNOC] South Texas Project Nuclear Operating Company. 2011c. Letter from G.T. Powell, 

Vice President, STPNOC, to NRC Document Control Desk. Subject: Response to RAI for the 

STP LRA. TAC Nos. ME4938 and ME5122. STP Letter No. NOC-AE-11002719. 

September 6, 2011. ADAMS No. ML11255A211.

[STPNOC] South Texas Project Nuclear Operating Company. 2011d. South Texas Project, 

Units 1 and 2. Radioactive Effluent Release Report for 2010. Wadsworth, TX. ADAMS 

No. ML11124A121.

[STPNOC] South Texas Project Nuclear Operating Company. 2011e. Letter from GT Powell, 

Vice President, STPNOC, to U.S. Nuclear Regulatory Commission, Document Control Desk. 

Subject: Response to RAI for the STP LRA. TAC Nos. ME4938 and ME5122. STP Letter No. 

NOC-AE-11002723. September 12, 2011. ADAMS No. ML11259A014.

[STPNOC] South Texas Project Nuclear Operating Company. 2011f. Letter from D.W. 

Rencurrel, Senior Vice President, STPNOC, to U.S. Nuclear Regulatory Commission, 

Document Control Desk. Subject: Response to Requests for Additional Information for the 

South Texas Project License Renewal Application (TAC Nos. ME4938 and ME5122) (STP 

Letter Number NOC-AE-1002761). November 17, 2011. ADAMS No. ML11333A094.

[STPNOC] South Texas Project Nuclear Operating Company. 2011g. Letter from G.T. Powell, 

Vice President, STPNOC, to U.S. Nuclear Regulatory Commission, Document Control Desk. 

Subject: Response to Requests for Additional Information for the South Texas Project License 

Renewal Application (TAC Nos. ME4938 and ME5122) (STP Letter Number NOC-AE-1 

1002691). July 5, 2011. ADAMS No. ML11193A074.

[STPNOC] South Texas Project Nuclear Operating Company. 2013a South Texas Project, 

Units 1 and 2. 2012 Radioactive Effluent Release Report. Wadsworth, TX. ADAMS 

No. ML13168A039.

[STPNOC] South Texas Project Nuclear Operating Company. 2013b. South Texas Project, 

Units 1 and 2. 2012 Annual Environmental and Annual Radiological Environmental Operating 

Reports. Wadsworth, TX. ADAMS Nos. ML13148A039 and ML13148A040.

[TCEQ] Texas Commission on Environmental Quality. 2005. TPDES Permit 

No. WQ0001908000. Austin, TX.

[TCEQ] Texas Commission on Environmental Quality. 2007. Letter from K Holligan, TCEQ, to 

RA Gangluff, STPNOC. Subject: Cooling water intake structures Phase II rules; South Texas 
Environmental Impacts of Operation

4-85

Project Electric Generating Station, TPDES Permit No. WQOOO 1908000. June 27, 2007. 

ADAMS No. ML 11256A057.

[TCEQ] Texas Commission on Environmental Quality. 2009. Amendment to Certificate of 

Adjudication, Certificate of Adjudication 14-5437 A. March 17, 2009. ADAMS 

No. ML11256A058.

[TDSHS] Texas Department of State Health Services. “Radiation Branch Environmental 

Monitoring Summary Reports.” Available at 

<http://www.dshs.state.tx.us/radiation/publications.shtm>.

Texas Water Code, Title 2, Water Administration, Subtitle B, “Water Rights,” Chapter 11, “Water 

Rights.” Available at <http://www.statutes.legis.state.tx.us/Docs/WA/htm/WA.11.htm>. 

[TPWD] Texas Parks and Wildlife Department. 2002. Executive Summary: The Texas Shrimp 

Fishery. A report to the Governor and the 77th Legislature of Texas. Texas Parks and Wildlife 

Department. September 2002.

[TPWD] Texas Parks and Wildlife Department. 2005. Land and Water Resources Conservation 

and Recreation Plan. Austin, TX: TPWD. 137 p. Available at 

<http://www.tpwd.state.tx.us/publications/pwdpubs/pwd_pl_e0100_0867/> (accessed 

26 September 2011).

[TPWD] Texas Parks and Wildlife Department. 2010. “Prairie Pothole and Marsh Wetlands.” 

Available at <http://www.texaswetlands.org/prairie.htm> (accessed 26 September 2011).

[TWDB] Texas Water Development Board. 2006. Water for Texas—2007. Austin, TX: TWDB. 

Volume II. Available at 

<http://www.twdb.state.tx.us/publications/reports/State_Water_Plan/2007/2007StateWaterPlan/

CHAPTER%202_REGIONAL%20K%20FINAL%20112706.pdf> (accessed 13 June 2011).

[TWDB] Texas Water Development Board. 2007. State Water Plan—Water for Texas 2007. 

Austin, TX: TWDB. Document No. GP-8-1. Volume 1. January 2007. Available at 

<http://www.twdb.state.tx.us/wrpi/swp/swp.asp> (accessed 31 August 2011).

[TWDB] Texas Water Development Board. 2011. “Water Resources Planning and 

Information, 2012 Draft State Water Plan & Public Comments.” Available at 

<http://www.twdb.state.tx.us/wrpi/swp/draft.asp> (accessed 21 October 2011).

[USCB] U.S. Census Bureau. 2010. “American FactFinder, Census 2000 and 2007–2009, 

3-Year Estimate, American Community Survey. State and County QuickFacts on Lucas, 

Ottawa, Sandusky and Wood Counties, Ohio. Housing Characteristics for 2000 and 2006–

2008, 3-Year Estimate.” Available at <http://factfinder.census.gov> and 

<http://quickfacts.census.gov> (accessed April 2011).

[USCB] U.S. Census Bureau. 2011. “American FactFinder, 2006–2010 American Community 

Survey 5-year estimates and Data Profile Highlights information on Brazoria, Calhoun, Fort 

Bend, Jackson, Matagorda, Victoria, and Wharton Counties and State of Texas.” Available at 

<http://factfinder.census.gov and http://quickfacts.census.gov> (accessed March 2012).

[USGCRP] U.S. Global Research Program. 2009. Global Climate Change Impacts in the 

United States. New York, NY: Cambridge University Press. Available at 

<http://downloads.globalchange.gov/usimpacts/pdfs/climate-impacts-report.pdf> (accessed 

31 August 2011).

Wilber D.H. and R. Bass. 1998. “Effect of the Colorado River Diversion on Matagorda Bay 

Epifauna.” Estuarine, Coastal and Shelf Science (1998) 47:309–318. 

5-1 

5.0 ENVIRONMENTAL IMPACTS OF POSTULATED ACCIDENTS

This chapter describes the environmental impacts from postulated accidents that might occur 

during the period of extended operation. The term “accident” refers to any unintentional event 

outside normal plant operations that results in a release, or the potential for a release, of 

radioactive materials into the environment. Two classes of postulated accidents are evaluated 

in the generic environmental impact statement (GEIS)—design-basis accidents (DBAs) and 

severe accidents (Table 5–1). 

Table 5–1. Issues Related to Postulated Accidents

Two issues related to postulated accidents are evaluated under the National Environmental 

Protection Act (NEPA) in the license renewal review—DBAs and severe accidents.

Issues Category

DBAs 1

Severe accidents 2

5.1 Design Basis Accidents

In order to receive U.S. Nuclear Regulatory Commission (NRC) approval to operate a nuclear 

power facility, an applicant for an initial operating license must submit a safety analysis report 

(SAR) as part of its application. The SAR presents the design criteria and design information for 

the proposed reactor and comprehensive data on the proposed site. The SAR also discusses 

various hypothetical accident situations and the safety features that are provided to prevent and 

mitigate accidents. The NRC staff (the staff) reviews the application to determine if the plant 

design meets the NRC’s regulations and requirements and includes, in part, the nuclear plant 

design and its anticipated response to an accident.

DBAs are those accidents that both the applicant and the staff evaluate to ensure that the plant 

can withstand normal and abnormal transients and a broad spectrum of postulated accidents, 

without undue hazard to the health and safety of the public. Many of these postulated accidents 

are not expected to occur during the life of the plant but are evaluated to establish the design 

basis for the preventive and mitigative safety systems of the nuclear power plant. The 

acceptance criteria for DBAs are described in Title 10 of the Code of Federal Regulations

(CFR) Part 50 (10 CFR Part 50) and 10 CFR Part 100.

The environmental impacts of DBAs are evaluated during the initial licensing process, and the 

ability of the plant to withstand these accidents is demonstrated to be acceptable before 

issuance of the operating license. The results of these evaluations are found in applicant

documentation such as the applicant’s final safety analysis report (FSAR), the staff’s safety 

evaluation report (SER), the final environmental statement (FES), and Section 5.1 of this 

supplemental environmental impact statement (SEIS). An applicant is required to maintain the 

acceptable design and performance criteria throughout the life of the nuclear power plant, 

including the period of extended operation. The consequences for these events are evaluated 

for the hypothetical maximum exposed individual; as such, changes in the plant environment will 

not affect these evaluations. Because of the requirements that continuous acceptability of the 

consequences and aging management programs (AMPs) be in effect for the period of extended 

operation, the environmental impacts, as calculated for DBAs, should not differ significantly from 

initial licensing assessments over the life of the plant, including the period of extended 

operation. Accordingly, the design of the plant, relative to DBAs during the period of extended 
Environmental Impacts of Postulated Accidents

5-2 

operation, is considered to remain acceptable; therefore, the environmental impacts of those 

accidents were not examined further in the GEIS.

The Commission has determined that the environmental impacts of DBAs are of SMALL 

significance for all nuclear power plants because the plants were designed to successfully 

withstand these accidents. Therefore, for the purposes of license renewal, DBAs are 

designated as a Category 1 issue. The early resolution of the DBAs (i.e., successfully withstand 

these accidents) makes them a part of the current licensing basis (CLB) of the plant. The CLB 

of the plant is to be maintained by the applicant under its current license; therefore, in 

accordance with 10 CFR 54.30, it is not subject to review under license renewal.

No new and significant information related to the South Texas Project (STP) was identified 

during the review of the South Texas Project Nuclear Operating Company, LLC (STPNOC) 

Environmental Report (ER) (STPNOC 2010), site audit (NRC 2011), the scoping process

(NRC 2012), or evaluation of other available information (including comments on the draft

SEIS). Therefore, there are no impacts related to these issues beyond those discussed in the 

GEIS. 

5.2 Severe Accidents

Severe nuclear accidents are those that are more severe than DBAs because they could result 

in substantial damage to the reactor core, whether or not there are serious offsite 

consequences. In the GEIS, the staff assessed the impacts of severe accidents during the 

period of extended operation, using the results of existing analyses and site-specific information 

to conservatively predict the environmental impacts of severe accidents for each plant during 

the period of extended operation.

Severe accidents initiated by external phenomena (e.g., tornadoes, floods, earthquakes, fires, 

and sabotage) have not traditionally been discussed in quantitative terms in FESs and were not 

specifically considered for the STP site in the GEIS (NRC 1996). However, the GEIS did 

evaluate existing impact assessments, including beyond design basis earthquakes, at existing 

plants—performed by NRC and by the industry at 44 nuclear plants in the U.S. In addition, the 

GEIS for license renewal performed a discretionary analysis of sabotages of plant systems in 

connection with license renewal. In the GEIS, the Commission concludes that the risk from 

sabotage and beyond design-basis earthquakes at existing plants is small and that the risks 

from other external events are adequately addressed by a generic consideration of internally 

initiated severe accidents (NRC 1996).

Based on information in the GEIS, the Commission found that:

The probability weighted consequences of atmospheric releases, fallout onto 

open bodies of water, releases to groundwater, and societal and economic 

impacts from severe accidents are small for all plants. However, alternatives to 

mitigate severe accidents must be considered for all plants that have not 

considered such alternatives.

The staff identified no new and significant information related to postulated accidents (DBAs and 

severe accidents) during the review of the STP ER (STPNOC 2010), site audit (NRC 2011), the 

scoping process (NRC 2012), or evaluation of other available information. Therefore, there are 

no impacts related to these issues beyond those discussed in the GEIS. However, in 

accordance with 10 CFR 51.53(c)(3)(ii)(L), the staff has reviewed severe accident mitigation 

alternatives (SAMAs) for STP. The results of the review are discussed in Section 5.3. 
Environmental Impacts of Postulated Accidents

5-3 

5.3 Severe Accident Mitigation Alternatives

Section 10 CFR 51.53(c)(3)(ii)(L) requires that license renewal applicants consider alternatives 

to mitigate severe accidents if the staff has not previously evaluated SAMAs for the applicant’s 

plant in an environmental impact statement (EIS) or related supplement or in an environmental 

assessment. The purpose of this consideration is to ensure that plant changes (e.g., hardware, 

procedures, and training) with the potential for improving severe accident safety performance 

are identified and evaluated. SAMAs have not been previously considered for STP; therefore, 

the remainder of Chapter 5 addresses those alternatives.

5.3.1 Overview of Severe Accident Mitigation Alternative Process

This section presents a summary of the SAMA evaluation for STP conducted by STPNOC, and 

the staff’s review of that evaluation. The staff performed its review with contract assistance from 

Pacific Northwest National Laboratory. The staff’s review is available in full in Appendix F of this 

SEIS, and the STPNOC’s SAMA evaluation is available in full in Attachment F of STPNOC’s ER 

(LRA Appendix E). 

STPNOC conducted the SAMA evaluation for STP with a four-step approach. In the first step, 

STPNOC quantified the level of risk associated with potential reactor accidents using the 

plant-specific probabilistic risk assessment (PRA) and other risk models.

In the second step, STPNOC examined the major risk contributors and identified possible ways 

(SAMAs) of reducing that risk. Common ways of reducing risk are changes to components, 

systems, procedures, and training.

In the third step, STPNOC estimated the benefits and the costs associated with each of the 

candidate SAMAs. Estimates were made of how much each SAMA could reduce risk. Those 

estimates were developed in terms of dollars, in accordance with NRC guidance for performing 

regulatory analyses. STPNOC also estimated the costs of implementing the candidate SAMAs.

Finally, in the fourth step, STPNOC compared the cost and benefit of each of the remaining 

SAMAs to determine whether the SAMA was cost beneficial, meaning the benefits of the SAMA 

were greater than the cost (a positive cost benefit).

5.3.2 Estimate of Risk

STPNOC submitted an assessment of SAMAs for STP as part of the ER (STPNOC 2010). This 

assessment was based on the most recent STP PRA available at that time, a plant-specific 

offsite consequence analysis performed using the MELCOR Accident Consequence Code 

System 2 (MACCS2) computer code, and insights from the STP individual plant examination 

(IPE) and individual plant examination of external events (IPEEE) (HL&P 1992).

Two distinct analyses are combined to form the basis for the risk estimates used in the SAMA 

analysis. The first is the STP Level 1 and Level 2 PRA model, which is an updated version of 

the IPE (HL&P 1992) which, in turn, was an update of the earlier model completed for the 

purpose of supporting changes in certain STP technical specifications (NRC 1994). The second 

is a supplemental analysis of offsite consequences and economic impacts (essentially a Level 3 

PRA model) developed specifically for the SAMA analysis. The SAMA analysis is based on the 

most recent STP Level 1 and Level 2 PRA model available at the time of the ER, referred to as 

the STP_REV6 model. The scope of the Level 1 model includes internal and external initiating 

events.
Environmental Impacts of Postulated Accidents

5-4 

The following results are based upon the STP model of record (STP_REV6), as presented in 

the ER (STPNOC 2010). The impact of the sensitivity analysis to updated fire and seismic data 

on the total core damage frequency (CDF) is provided in Appendix F, Sections F.2.2 (risk 

estimates) and F.6.2 (cost-benefit evaluation) of this SEIS.

The STP CDF is approximately 6.4×10-6 per year for both internal and external events as 

determined from quantification of the Level 1 PRA model. The CDF is based on the risk 

assessment for internally initiated events, which includes internal flooding, and external events, 

which includes fire, seismic events, external flooding, and tornado events. The internal events 

CDF is approximately 3.9×10-6 per year, and the external events CDF is approximately 2.5×10-6

per year. The external events CDF includes contributions of approximately 1.0×10-6 per year 

due to fire events, 7.3×10-8 per year due to seismic events, and 1.4×10-6 per year due to other 

external events (STPNOC 2010).

When determined from the sum of the containment event tree (CET) sequences, or Level 2 

PRA model, the CDF is approximately 6.2×10-6 per year (within acceptable approximation) for 

both internal and external events. The 6.2×10-6 value derived from the CET was used as the 

baseline CDF in the SAMA evaluations (STPNOC 2010).

The breakdown of CDF by initiating event is provided in Table 5–2, Table 5–3, Table 5–4, and 

Table 5–5 for internal, fire, seismic, and other external events, respectively (STPNOC 2011).
Environmental Impacts of Postulated Accidents

5-5 

Table 5–2. STP Core Damage Frequency for Internal Events

Initiating event (a) CDF

(per year)

% Contribution 

to internal events 

CDF(b, c)

% Contribution 

to total CDF

Loss of all offsite power 9.6×10-7 25 15

Loss of 345 kV offsite power 6.3×10-7 16 10

Steam generator tube rupture (SGTR) 4.4×10-7 11 7

Excessive loss-of-coolant accident (LOCA) 3.2×10-7 8 5

Steam line break outside containment 2.8×10-7 7 4

Loss of electrical auxiliary building heating, 

ventilation, and air conditioning (HVAC) 

2.6×10-7 7 4

Turbine trip 1.8×10-7 5 3

Partial loss of main feedwater 1.5×10-7 4 2

Reactor coolant pump (RCP) seal LOCA 1.5×10-7 4 2

Interfacing system LOCA 1.3×10-7 3 2

Loss of DC busses 9.7×10-8 2 2

Small LOCAs 7.5×10-8 2 1

Reactor trip 6.5×10-8 2 1

Other internal events 3.6×10-7 9 6

Total CDF (internal events) 3.9×10-6 100 64

(a) The impact of the sensitivity analysis to updated fire and seismic data on the total CDF is not included in these 

results. Section F.2.2 provides a discussion of these impacts.

(b) Obtained from CDF given in ER Table F.2-1 (STPNOC 2010) divided by the total internal events CDF of 

3.89×10-6. (c) May not total to 100 percent due to round off.
Environmental Impacts of Postulated Accidents

5-6 

Table 5–3. STP Core Damage Frequency for Fire Events

Fire initiator description (a) CDF 

(per year)

% Contribution to 

fire CDF(b, c)

% Contribution to 

total CDF

Fire zone 047 scenario X 4.0×10-7 39 6

Fire zone 071 scenario X 2.1×10-7 21 3

Fire zone 047 scenario B 1.8×10-7 18 3

Control room fire scenario 18 1.2×10-7 12 2

Fire zone 047 scenario BC 6.4×10-8 6 1

Control room fire scenario 23 2.6×10-8 3 0.4

Fire zone 147 scenario O 1.1×10-8 1 0.2

Control room fire scenario 10 1.0x10-9 <1 <0.1

Total CDF (fire events) 1.0×10-6 100 16

(a) The impact of the sensitivity analysis to updated fire and seismic data on the total CDF is not included in these 

results. Section F.2.2 provides a discussion of these impacts.

(b) Obtained from CDF given in ER Table F.2-1 (STPNOC 2010) divided by fire events CDF of 1.02×10-6. (c) May not total to 100 percent due to round off.

Table 5–4. STP Core Damage Frequency for Seismic Events

Initiating event(a) CDF

(per year)

% Contribution to 

seismic CDF (b, c)

% Contribution to 

total CDF

Seismic event, 0.4g acceleration 4.1×10-8 55 0.6

Seismic event, 0.6g acceleration 2.1×10-8 28 0.3

Seismic event, 0.2g acceleration 9.8×10-9 13 0.2

Seismic event, 0.1g acceleration 2.1×10-9 3 <0.1

Total CDF (seismic events) 7.3×10-8 100 1.1

(a) The impact of the sensitivity analysis to updated fire and seismic data on the total CDF is not included in these 

results. Section F.2.2 provides a discussion of these impacts.

(b) Obtained from CDF given in ER Table F.2-1 (STPNOC 2010) divided by seismic events CDF of 7.31×10-8. (c) May not total to 100 percent due to round off.
Environmental Impacts of Postulated Accidents

5-7 

Table 5–5. STP Core Damage Frequency for Other External Events

Initiating event (a) CDF

(per year)

% Contribution 

to other external 

events CDF (b, c)

% Contribution 

to total CDF

Tornado induced failure of switchyard and 

essential cooling pond (ECP)

1.1×10-6 79 17

Essential cooling water (ECW) failure due to 

breach of main cooling reservoir (MCR)

2.9×10-7 21 5

External flooding scenarios 2–6 9.5×10-9 <1 0.2

Flood induced loss of offsite power (LOOP) 2.1×10-9 <1 <0.1

Total CDF (other external events) 1.4×10-6 100 22

(a) The impact of the sensitivity analysis to updated fire and seismic data on the total CDF is not included in these 

results. See Section F.2.2 for a discussion of these impacts.

(b) Obtained from CDF given in ER Table F.2-1 (STPNOC 2010) divided by other external events CDF of 1.41 × 10-6. (c) May not total to 100 percent due to round off.

As shown in Table 5–2, internal events contribute about 61 percent of the total CDF. The two 

LOOP events—“Loss of All Offsite Power” and “Loss of 345 kV Offsite Power”—are the largest 

contributors to the internal event CDF.

As shown in Table 5–5, the CDF for other external events make up the next largest contributor

(about 22 percent) of the total CDF. The “Tornado Induced Failure of Switchyard and Essential 

Cooling Pond (ECP)” and “Essential Cooling Water (ECW) Failure due to Breach of Main 

Cooling Reservoir (MCR)” are the largest contributors in this group. 

As shown in Table 5–3, fire events make up the next largest contributor (about 16 percent) of

the total CDF. The “Fire Zone 047 Scenario X” and “Fire Zone 071 Scenario X” are the largest 

contributors. Seismic events make up a small contribution of about 1 percent to the total STP 

CDF. Station blackout contributes about 35 percent (2.2×10-6 per year) of the total CDF while 

anticipated transients without scram (ATWS) contribute about 4 percent (2.8×10-7 per year) to 

the total CDF (STPNOC 2011).

In the ER, STPNOC estimated the dose to the population within 80 km (50 mi) of the STP site to 

be approximately 0.0174 person-Sievert (Sv) (1.74 person-roentgen equivalent man (rem)) per 

year. The breakdown of the total population dose by containment release mode is summarized 

in Table 5–6. Large early releases, with induced SGTR and interfacing systems loss of coolant 

accident (ISLOCA), are the dominant contributors to the population dose risk at STP. Small 

early releases with pre-existing small containment failure and late releases with no sprays are 

also significant contributors to the population dose risk. 
Environmental Impacts of Postulated Accidents

5-8 

Table 5–6. Breakdown of Population Dose by Containment Release Mode

Containment release mode (a)

Population dose 

(person-rem (b) 

per year) % Contribution 

Large early releases (<3 hrs) 0.68 39

Small early releases (<3 hrs) 0.59 34

Late releases (>3 hrs) 0.42 24

Intact containment 0.05 3

Total 1.74 100

(a) The impact of the sensitivity analysis to updated fire and seismic data on the release category frequency is not 

included in these results. Section F.2.2 provides a discussion of these impacts.

(b) One person-rem=0.01 person-Sv 

The staff has reviewed STPNOC’s data and evaluation methods and concludes that the quality 

of the risk analyses is adequate to support an assessment of the risk reduction potential for 

candidate SAMAs. Accordingly, the staff based its assessment of offsite risk on the CDFs and 

offsite doses reported by STPNOC.

5.3.3 Potential Plant Improvements

STPNOC’s process for identifying potential plant improvements (SAMAs) consisted of the 

following elements:

• review of the dominant cutsets and most significant basic events from the 

current, plant-specific PRA,

• review of potential plant improvements identified in the STP IPE and IPEEE,

• review of SAMA candidates identified for license renewal applications for 

representative PWR plants, and

• review of other industry documentation discussing potential plant 

improvements.

Based on this process, an initial set of 21 candidate SAMAs, referred to as Phase I SAMAs, 

were identified. In Phase I of the evaluation, STPNOC performed a qualitative screening of the 

initial list of SAMAs and eliminated SAMAs from further consideration using the following 

criteria: 

• The SAMA is not applicable to STP due to design differences. 

• The SAMA has already been implemented at STP or would achieve results 

that have already been achieved at STP by other means. 

• The SAMA has estimated implementation costs that would exceed the dollar 

value associated with eliminating all severe accident risk at STP.

Based on this screening, 16 SAMAs were eliminated, leaving 5 SAMAs for further evaluation. A 

detailed cost-benefit analysis was performed for each of the 5 SAMAs in the Phase II analysis. 

STPNOC calculated the risk reduction that would be attributable to each candidate SAMA 

(assuming SAMA implementation) and re-quantified the risk value. The difference between the 

base risk value and the SAMA-reduced risk value is the averted risk, or the value of 

implementing the SAMA. STPNOC used this information in conjunction with the cost estimates 
Environmental Impacts of Postulated Accidents

5-9 

for implementing each SAMA to perform a detailed cost-benefit comparison. STPNOC 

performed additional analyses to evaluate how the SAMA results would change if certain key 

parameters were changed, including re-assessing the cost-benefit calculations using the 

95th percentile level of the failure probability distributions. The results of the uncertainty 

analysis are discussed in the ER, Attachment F, Section F.7. Based on the results of this 

SAMA analysis, none of the SAMAs have a positive net value, even when the 95th percentile 

PRA results were considered. Therefore, no SAMAs are being considered for implementation 

as part of license renewal (STPNOC 2010). The staff’s concerns regarding SAMAs were 

provided to STPNOC in RAIs (NRC 2011). The staff’s RAIs did not result in the identification of 

any potentially cost-beneficial SAMAs (STPNOC 2011). STPNOC’s SAMA analyses and the 

NRC’s review are discussed in more detail in the following sections. 

The NRC staff concludes that STPNOC used a systematic and comprehensive process for 

identifying potential plant improvements for STP and that the set of SAMAs evaluated in the ER, 

together with those evaluated in response to the NRC staff’s inquiries, is reasonably 

comprehensive and, therefore, is acceptable. 

5.3.4 Evaluation of Risk Reduction and Costs of Improvements

STPNOC estimated the costs of implementing the 21 SAMAs through the development of 

site-specific cost estimates and use of other applicants’ estimates for similar improvements. 

The costs were developed on a site basis (i.e., two units). If the cost estimate was for a single 

unit, based on other applicants’ estimates for similar improvements, then the cost estimate was 

multiplied by two to derive the costs on a site basis. The site-specific cost estimates 

conservatively did not include contingency costs associated with unforeseen implementation 

obstacles or the cost of replacement power during extended outages required to implement the 

modifications (STPNOC 2010). The cost estimates that were based on other applicants’ 

estimates did not account for inflation, which is considered another conservatism.

STPNOC performed additional analyses to evaluate the impact of parameter choices and 

uncertainties on the results of the SAMA assessment. In this process, one additional SAMA 

was identified for detailed cost-benefit analysis.

The staff reviewed STPNOC’s basis for calculating the risk reduction for the various plant 

improvements and concludes that the rationale and assumptions for estimating risk reduction 

are reasonable and generally conservative (i.e., the estimated risk reduction is higher than what 

would actually be realized). Accordingly, the staff based its estimates of averted risk for the 

various SAMAs on STPNOC’s risk reduction estimates.

5.3.5 Cost-Benefit Comparison

The methodology used by STPNOC to perform the Cost-Benefit Comparison in the Phase II

analysis was based on NRC’s guidance for performing a cost-benefit analysis

(i.e., NUREG/BR-0184, Regulatory Analysis Technical Evaluation Handbook (NRC 1997)). The 

guidance involves determining the net value for each SAMA. If the net value of a SAMA is 

negative, the cost of implementing the SAMA is larger than the benefit associated with the 

SAMA, and it is not considered cost beneficial. Revision 4 of NUREG/BR-0058 states that two 

sets of estimates should be developed, one at a 3 percent discount rate and one at a 7 percent

discount rate (NRC 2004). STPNOC provided a base set of results using the 7 percent discount 

rate and a sensitivity study using the 3 percent discount rate. These results are presented in 

Table 5–7 as the total benefit baseline and total benefit baseline with uncertainty. Table 5–7

lists (a) the assumptions considered to estimate the risk reduction for each of the evaluated 

SAMAs, (b) the estimated risk reduction in terms of percent reduction in CDF and population 
Environmental Impacts of Postulated Accidents

5-10

dose, and (c) the estimated total benefit (present value) of the averted risk. The estimated 

benefits reported in Table 5–7 reflect the combined benefit in both internal and external events. 

There are six SAMAs listed in Table 5–7. The associated initiated events for these six SAMAs 

are: 

• cable spreading room fire, 

• ISLOCA, 

• SGTR, 

• loss of reactor coolant system (RCS) water seal, 

• loss of standby diesel generator (SBDG) HVAC, and

• loss of essential cooling water intake structure (ECWIS) HVAC, respectively. 

The staff reviewed the bases for the applicant’s cost estimates. For certain improvements, the 

staff also compared the cost estimates to estimates developed elsewhere for similar 

improvements, including estimates developed as part of other applicants’ analyses of SAMAs 

for operating reactors. The staff reviewed the costs and has found them to be reasonable and 

generally consistent with estimates provided in support of other plants’ analyses. The staff 

agrees that the costs of the SAMAs evaluated would be higher than the associated benefits 

when they are considered independently.

Table 5–7. Phase II SAMA List (Cost-Benefit) for STP

SAMA(a) Assumptions

% Risk reduction Total benefit ($)

Cost ($)

CDF(b)

Population 

dose (% dose 

reduction)

Baseline 

(internal 

+ external)

Baseline with 

uncertainty(b)

3b(c)—Install fire 

wrap on positive 

displacement 

pump (PDP) 

cables in cable 

spreading room.

Eliminate failure of the 

PDP due to a fire in 

the cable spreading 

room.

<1 <1 3K 4K 800K

4—Develop 

procedures to 

isolate component 

cooling water 

(CCW) inside 

containment.

Eliminate failure of the 

operator action to 

isolate CCW.

2 10 27K 43K 100K
Environmental Impacts of Postulated Accidents

5-11

SAMA(a) Assumptions

% Risk reduction Total benefit ($)

Cost ($)

CDF(b)

Population 

dose (% dose 

reduction)

Baseline 

(internal 

+ external)

Baseline with 

uncertainty(b)

10—Enhance 

procedures to 

ensure the steam 

generators (SGs) 

are filled or 

maintain filled in 

SGTR events to 

scrub fission 

products.

Reassign a portion of 

the SGTR CDF 

contribution for the 

large early release 

category (7.48E-06 

per year) and late 

release category 

(1.35E-07 per year) to 

the small early release 

category and intact 

containment release 

category, respectively. 

0 2 3K 5K 100K

12—Enhance 

procedures to 

prevent clearing of 

RCS cold leg 

water seals.

Reassign the induced 

SGTR CDF 

contribution (2.4E-09 

per year) for 

sequences in which 

offsite power is 

available from the 

large early release 

category to the intact 

containment release 

category.

0 0 <1K <1K 100K

13—Develop 

procedures to 

open doors or use 

portable fans for 

alternate SBDG

room cooling.

Eliminate failure of the 

operator action to 

provide SBDG room 

cooling.

<1 0 1K 2K 100K

15—Develop 

emergency 

procedures for 

alternate ECWIS 

room cooling.

Eliminate failure of the 

operator action to 

provide ECWIS room 

cooling.

1 2 8K 12K 100K

(a) SAMAs in bold are potentially cost beneficial.

(b) Baseline benefits increased by a factor of 1.6 to account for uncertainties, which is discussed further in Section F.6.2.

(c) SAMA 3b retained for Phase II analysis based on results of uncertainty analysis, which is discussed further in 

Section F.6.2. 

5.3.6 Conclusions

The NRC staff reviewed the STPNOC’s analysis. The staff concludes that the methods used 

and the implementations of those methods were sound. The treatment of SAMA benefits and 

costs supports the general conclusion that the SAMA evaluations performed by STPNOC are 

reasonable and sufficient for the license renewal submittal. 
Environmental Impacts of Postulated Accidents

5-12

The staff agrees with STPNOC’s conclusion that none of the candidate SAMAs are potentially 

cost beneficial. This conclusion is based on the generally conservative treatment of costs and 

benefits. This conclusion is consistent with the low residual level of risk indicated in the STP 

PRA and the fact that STPNOC has already implemented the plant improvements identified 

from the IPE and IPEEE.

5.4 References

10 CFR Part 50. Code of Federal Regulations, Title 10, Energy, Part 50, “Domestic Licensing of 

Production and Utilization Facilities.” 

10 CFR Part 51. Code of Federal Regulations, Title 10, Energy, Part 51, “Environmental 

protection regulations for domestic licensing and related regulatory functions.” 

10 CFR Part 54. Code of Federal Regulations, Title 10, Energy, Part 54, “Requirements for 

Renewal of Operating Licenses for Nuclear Power Plants.” 

10 CFR Part 100. Code of Federal Regulations, Title 10, Energy, Part 100, “Reactor Site 

Criteria.” 

[HL&P] Houston Lighting and Power Company. 1992. “South Texas Project Electric 

Generating Station Level 2 Probabilistic Safety Assessment and Individual Plant Examination.” 

August 1992. (ADAMS Nos. ML0617001702, ML0617001790, ML0617001850).

[NRC] U.S. Nuclear Regulatory Commission. 1994. Letter from Suzanne C. Black, Director, to 

William T. Cottle, Houston Lighting & Power Company. Subject: Issuance of Amendment 

Nos. 59 and 47 to Facility Operating License Nos. NPF-76 and NPF-80 and Related Relief 

Request—South Texas Project, Units 1 and 2 (TAC Nos. M76048 and M76049). 

February 17, 1994. ADAMS No. ML021300134.

[NRC] U.S. Nuclear Regulatory Commission. 1996. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. Washington, DC. NRC NUREG-1437. May 1996. 

ADAMS Nos. ML040690705 and ML040690738.

[NRC] U.S. Nuclear Regulatory Commission. 1997. Regulatory Analysis Technical Evaluation 

Handbook. Washington, DC. NRC. NUREG/BR-0184. January 1997. ADAMS 

No. ML050190193.

[NRC] U.S. Nuclear Regulatory Commission. 2004. Regulatory Analysis Guidelines of the U.S. 

Nuclear Regulatory Commission. Washington, DC. NRC NUREG/BR-0058, Rev. 4. July 2000. 

ADAMS No. ML003738939.

[NRC] U.S. Nuclear Regulatory Commission. 2011. Summary of site audit related to the review 

of the license renewal application for South Texas Project, Units 1 and 2. August 4, 2011. 

ADAMS No. ML11196A005.

[NRC] U.S. Nuclear Regulatory Commission. 2012. Environmental Impact Statement Scoping 

Process, Summary Report, South Texas Project, Units 1 and 2, Bay City, TX. Washington, DC. 

NRC. 2012. ADAMS No. ML11153A082.

[STPNOC] South Texas Project Nuclear Operating Company. 2010. “South Texas Project, 

Applicant’s Environmental Report—Operating License Renewal Stage, South Texas Project 

Units 1 & 2.” September 2010. ADAMS No. ML103010263.

[STPNOC] South Texas Project Nuclear Operating Company. 2011. Letter from G.T. Powell, 

STPNOC, to U.S. Nuclear Regulatory Commission Document Control Desk, Subject: South 

Texas Project Units 1 and 2, Docket Nos. STN 50-498, STN 50-499, Response to Request for 
Environmental Impacts of Postulated Accidents

5-13

Additional Information on South Texas Project License Renewal Application (TAC No. ME4938). 

July 5, 2011. ADAMS No. ML11193A016.

[STPNOC] South Texas Project Nuclear Operating Company. 2011b. Letter from G.T. Powell, 

STPNOC, to U.S. Nuclear Regulatory Commission Document Control Desk, Subject: South 

Texas Project Units 1 and 2, Docket Nos. STN 50-498, STN 50-499, Response to Request for 

Additional Information on South Texas Project License Renewal Application (TAC No. ME4938). 

August 23, 2011. ADAMS No. ML11250A067.

[STPNOC] South Texas Project Nuclear Operating Company. 2012b. Letter from D.W. 

Rencurrel, STPNOC, to U.S. Nuclear Regulatory Commission Document Control Desk, Subject: 

South Texas Project Units 1 and 2, Docket Nos. STN 50-498, STN 50-499, Clarification to 

Supplemental Response to Request for Additional Information on South Texas Project License 

Renewal Application—SAMA (TAC Nos. ME4938 and ME5122). February 16, 2012. ADAMS 

No. ML12053A259.

6-1 

6.0 ENVIRONMENTAL IMPACTS OF THE URANIUM FUEL CYCLE, 

WASTE MANAGEMENT, AND GREENHOUSE GAS EMISSIONS

This chapter addresses issues related to the uranium fuel cycle, solid waste management, and 

greenhouse gas (GHG) emissions during the proposed 20-year period of extended operation.

6.1 The Uranium Fuel Cycle

The uranium fuel cycle includes uranium mining and milling, the production of uranium 

hexafluoride, isotopic enrichment, fuel fabrication, reprocessing of irradiated fuel, transportation 

of radioactive materials, and management of low-level wastes and high-level wastes related to 

uranium fuel cycle activities. The generic potential impacts of the radiological and

nonradiological environmental impacts of the uranium fuel cycle and transportation of nuclear 

fuel and wastes are described in detail in NUREG-1437, Generic Environmental Impact 

Statement (GEIS) for License Renewal of Nuclear Plants (NRC 1996, 1999) based, in part, on 

the generic impacts given in Table S–3, “Table of Uranium Fuel Cycle Environmental Data,” 

located at Title 10, Part 51.51, of the Code of Federal Regulations (10 CFR 51.51), and in 

10 CFR 51.52(c), Table S–4, “Environmental Impact of Transportation of Fuel and Waste to and 

from One Light-Water-Cooled Nuclear Power Reactor.”

In the GEIS, the U.S. Nuclear Regulatory Commission (NRC) staff identified nine Category 1 

issues related to the fuel cycle and waste management, which appear in Table 6–1. There are 

no Category 2 issues related to the fuel cycle and waste management.

Table 6–1. Issues Related to the Uranium Fuel Cycle and Waste Management

Issues GEIS Sections Category

Offsite radiological impacts (individual effects 

from other than the disposal of spent fuel & 

high-level waste)

6.1; 6.2.1; 6.2.2.1; 6.2.2.3; 6.2.3; 6.2.4; 6.6 1 

Offsite radiological impacts (collective effects) 6.1; 6.2.2.1; 6.2.3; 6.2.4; 6.6 1 

Offsite radiological impacts (spent fuel and 

high-level waste disposal)

6.2.2.1; 6.2.2.2; 6.2.3; 6.2.4 1 

Nonradiological impacts of the uranium fuel

cycle

6.1; 6.2.2.6; 6.2.2.7; 6.2.2.8; 6.2.2.9; 6.2.3; 6.2.4; 

6.6 1 

Low-level waste storage & disposal

6.1; 6.2.2.2;6.4.2; 6.4.3; 6.4.3.1; 6.4.3.2; 6.4.3.3; 

6.4.4; 6.4.4.1; 6.4.4.2; 6.4.4.3; 6.4.4.4; 6.4.4.5; 

6.4.4.5.1; 6.4.4.5.2; 6.4.4.5.3; 6.4.4.5.4; 

6.4.4.6;6.6

1 

Mixed waste storage & disposal 6.4.5.1; 6.4.5.2; 6.4.5.3; 6.4.5.4; 6.4.5.5; 6.4.5.6; 

6.4.5.6.1; 6.4.5.6.2; 6.4.5.6.3; 6.4.5.6.4; 6.6 1 

Onsite spent fuel 6.1; 6.4.6; 6.4.6.1; 6.4.6.2; 6.4.6.3; 6.4.6.4; 

6.4.6.5; 6.4.6.6; 6.4.6.7; 6.6 1 

Nonradiological waste 6.1; 6.5; 6.5.1; 6.5.2; 6.5.3; 6.6 1

Transportation 6.1; 6.3.1; 6.3.2.3; 6.3.3; 6.3.4; 6.6, Addendum 1 1
Environmental Impacts of the Uranium Fuel Cycle, 

Waste Management, and Greenhouse Gas Emissions

6-2 

The NRC staff’s evaluation of the environmental impacts associated with spent nuclear fuel is 

addressed in two issues in Table 6–1, “Offsite radiological impacts (spent fuel and high-level 

waste disposal)” and “Onsite spent fuel.” However, as explained later in this section, the scope 

of the evaluation of these two issues in this supplemental environmental impact statement 

(SEIS) has been revised. The issue, “Offsite radiological impacts (spent fuel and high-level 

waste disposal),” from Table 6–1, is not evaluated in this SEIS. In addition, the issue, “Onsite 

spent fuel” only evaluates the environmental impacts during the license renewal term.

For the term of license renewal, the NRC staff did not identify any new and significant 

information related to the remaining uranium fuel cycle and waste management issues listed in

Table 6-1 during its review of the STP Nuclear Operating Company (STPNOC) Environmental 

Report (STPNOC 2010), the site visit, and the scoping process. Therefore, there are no 

impacts related to these issues beyond those discussed in the GEIS. For these Category 1 

issues, the GEIS concludes that the impacts are SMALL, except for the issue, “Offsite 

radiological impacts (collective effects),” which the NRC has not assigned an impact level. This 

issue assesses the 100-year radiation dose to the U.S. population (i.e., collective effects or 

collective dose) from radioactive effluents released as part of the uranium fuel cycle for a 

nuclear power plant during the license renewal term compared to the radiation dose from 

natural background exposure. It is a comparative assessment for which there is no regulatory 

standard to base an impact level.

For the offsite radiological impacts resulting from spent fuel and high-level waste disposal and 

the onsite storage of spent fuel, which will occur after the reactors have been permanently shut

down, the NRC’s Waste Confidence rule represented the Commission’s generic determination 

that spent fuel can continue to be stored safely and without significant environmental impacts for 

a period of time after the end of the licensed life for operation. This generic determination 

meant that the NRC did not need to consider the storage of spent fuel after the end of a 

reactor’s licensed life for operation in National Environmental Policy Act (NEPA) documents that 

support its reactor and spent fuel storage application reviews. 

The NRC first adopted the Waste Confidence rule in 1984. The NRC amended the rule in 1990, 

reviewed it in 1999, and amended it again in 2010 (49 FR 34694; 55 FR 38474; 64 FR 68005; 

and 75 FR 81032 and 81037). The Waste Confidence rule is codified in 10 CFR 51.23.

On December 23, 2010, the Commission published in the Federal Register a revision of the 

Waste Confidence rule to reflect information gained from experience in the storage of spent fuel 

and the increased uncertainty in the siting and construction of a permanent geologic repository 

for the disposal of spent fuel and high-level waste (75 FR 81032 and 81037). In response to the 

2010 Waste Confidence rule, the states of New York, New Jersey, Connecticut, and Vermont—

along with several other parties—challenged the Commission’s NEPA analysis in the decision, 

which provided the regulatory basis for the rule. On June 8, 2012, the United States Court of 

Appeals, District of Columbia Circuit in New York v. NRC, 681F.3d 471 (D.C. Cir. 2012) vacated

the NRC’s Waste Confidence rule after finding that it did not comply with NEPA. 

In response to the court’s ruling, the Commission, in CLI-12-16 (NRC 2012a), determined that it

would not issue licenses that rely upon the Waste Confidence rule, until the issues identified in 

the court’s decision are appropriately addressed by the Commission. In CLI-12-16, the 

Commission also noted that the decision not to issue licenses only applies to final license 

issuance; all licensing reviews and proceedings should continue to move forward.

In addition, the Commission directed, in SRM-COMSECY-12-0016 (NRC 2012b), that the NRC 

staff proceed with a rulemaking that includes the development of a generic environmental 

impact statement (EIS) to support a revised Waste Confidence rule and to publish both the EIS 
Environmental Impacts of the Uranium Fuel Cycle, 

Waste Management, and Greenhouse Gas Emissions

6-3 

and the revised rule in the Federal Register within 24 months (by September 2014). The 

Commission indicated that both the EIS and the revised Waste Confidence rule should build on 

the information already documented in various NRC studies and reports, including existing 

environmental assessments that the NRC developed as part of the 2010 Waste Confidence 

rule. The Commission directed that any additional analyses should focus on the issues 

identified in the court’s decision. The Commisssion also directed that the NRC staff provide

ample opportunity for public comment on both the draft EIS and the proposed Waste 

Confidence rule. 

The revised rule and supporting EIS are expected to provide the necessary NEPA analyses of 

waste confidence-related human health and environmental issues. As directed by the 

Commission, the NRC will not issue a renewed license before the resolution of waste 

confidence-related issues. This will ensure that there would be no irretrievable or irreversible

resource commitments or potential harm to the environment before waste confidence impacts 

have been addressed.

If the results of the Waste Confidence rule and supporting EIS identify information that requires 

a supplement to this SEIS, the NRC staff will perform any appropriate additional NEPA review 

for those issues before the NRC makes a final licensing decision.

6.2 Greenhouse Gas Emissions

This section discusses the potential impacts from GHGs emitted from the nuclear fuel cycle. 

The GEIS does not directly address these emissions, and its discussion is limited to an 

inference that substantial carbon dioxide emissions may occur if coal- or oil-fired alternatives to 

license renewal are carried out.

6.2.1 Existing Studies

Since the development of the GEIS, the relative volumes of GHGs emitted by nuclear and other 

electricity generating methods have been widely studied. However, estimates and projections 

of the carbon footprint of the nuclear power lifecycle vary depending on the type of study done. 

Additionally, considerable debate also exists among researchers on the relative effects of 

nuclear and other forms of electricity generation on GHG emissions. Existing studies on GHG 

emissions from nuclear power plants generally take two different forms:

(1) qualitative discussions of the potential to use nuclear power to reduce GHG 

emissions and mitigate global warming, and

(2) technical analyses and quantitative estimates of the actual amount of GHGs 

generated by the nuclear fuel cycle or entire nuclear power plant life cycle and 

comparisons to the operational or life cycle emissions from other energy generation 

alternatives. 

Qualitative Studies. The qualitative studies consist primarily of broad evaluations, large-scale 

public policy evaluations, or investment evaluations of whether an expansion of nuclear power is 

likely to be a technically, economically, or politically workable means of achieving global GHG 

reductions. Studies found by the staff during the subsequent literature search include the 

following:

• Evaluations to determine if investments in nuclear power in developing 

countries should be accepted as a flexibility mechanism to assist 

industrialized nations in achieving their GHG reduction goals under the Kyoto 
Environmental Impacts of the Uranium Fuel Cycle, 

Waste Management, and Greenhouse Gas Emissions

6-4 

Protocols (IAEA 2000; NEA 2002; Schneider 2000). Ultimately, the parties to 

the Kyoto Protocol did not approve nuclear power as a component under the 

clean development mechanism (CDM) due to safety and waste disposal 

concerns (NEA 2002).

• Analyses developed to assist governments, including the U.S. Government, 

in making long-term investment and public policy decisions in nuclear power 

(Hagen et al. 2001; Keepin 1988; MIT 2003).

Although the qualitative studies sometimes reference and critique the existing quantitative 

estimates of GHGs produced by the nuclear fuel cycle or life cycle, their conclusions generally 

rely heavily on discussions of other aspects of nuclear policy decisions and investment such as 

safety, cost, waste generation, and political acceptability. Therefore, these studies are typically 

not directly applicable to an evaluation of GHG emissions associated with the proposed license 

renewal for a given nuclear power plant.

Quantitative Studies. A large number of technical studies, including calculations and estimates 

of the amount of GHGs emitted by nuclear and other power generation options, are available in 

the literature and were useful to the staff’s efforts in addressing relative GHG emission levels. 

Examples of these studies include—but are not limited to—Mortimer (1990), 

Andseta et al. (1998), Spadaro (2000), Storm van Leeuwen and Smith (2008), Fritsche (2006), 

Parliamentary Office of Science and Technology (POST) (2006), Atomic Energy Authority 

(AEA) (2006), Weisser (2006), Fthenakis and Kim (2007), and Dones (2007).

Comparing these studies and others like them is difficult because the assumptions and 

components of the lifecycles the authors evaluate vary widely. Examples of areas in which 

differing assumptions make comparing the studies difficult include the following:

• energy sources that may be used to mine uranium deposits in the future,

• reprocessing or disposal of spent nuclear fuel,

• current and potential future processes to enrich uranium and the energy 

sources that will power them,

• estimated grades and quantities of recoverable uranium resources,

• estimated grades and quantities of recoverable fossil-fuel resources,

• estimated GHG emissions other than carbon dioxide, including the 

conversion to carbon dioxide equivalents per unit of electric energy produced,

• performance of future fossil-fuel power systems,

• projected capacity factors for alternatives means of generation, and

• current and potential future reactor technologies.

In addition, studies may vary with respect to whether all or parts of a power plant’s lifecycle are 

analyzed (i.e., a full lifecycle analysis will typically address plant construction, operations, 

resource extraction (for fuel and construction materials), and decommissioning, whereas a 

partial lifecycle analysis primarily focuses on operational differences). 

In the case of license renewal, a GHG analysis for that portion of the plant’s lifecycle (operation 

for an additional 20 years) would not involve GHG emissions associated with construction 

because construction activities have already been completed at the time of relicensing. In 

addition, the proposed action of license renewal would also not involve additional GHG 
Environmental Impacts of the Uranium Fuel Cycle, 

Waste Management, and Greenhouse Gas Emissions

6-5 

emissions associated with facility decommissioning because that decommissioning must occur 

whether the facility is relicensed or not. However, in some of the above-mentioned studies, the 

specific contribution of GHG emissions from construction, decommissioning, or other portions of 

a plant’s lifecycle cannot be clearly separated from one another. In such cases, an analysis of 

GHG emissions would overestimate the GHG emissions attributed to a specific portion of a 

plant’s lifecycle. Nonetheless, these studies supply some meaningful information with respect 

to the relative magnitude of the emissions among nuclear power plants and other forms of 

electric generation, as discussed in the following sections.

In Table 6–2, Table 6–3, and Table 6–4, the staff presents the results of the above-mentioned 

quantitative studies to supply a weight-of-evidence evaluation of the relative GHG emissions 

that may result from the proposed license renewal as compared to the potential alternative use 

of coal-fired, natural gas-fired, and renewable generation. Most studies from Mortimer (1990) 

onward suggest that uranium ore grades and uranium enrichment processes are leading 

determinants in the ultimate GHG emissions attributable to nuclear power generation. These 

studies show that the relatively lower order of magnitude of GHG emissions from nuclear power, 

when compared to fossil-fueled alternatives (especially natural gas), could potentially disappear 

if available uranium ore grades drop sufficiently while enrichment processes continued to rely on 

the same technologies.

Summary of Nuclear Greenhouse Gas Emissions Compared to Coal. Considering that coal 

fuels the largest share of electricity generation in the U.S. and that its burning results in the 

largest emissions of GHGs for any of the likely alternatives to nuclear power generation, 

including South Texas Project (STP), most of the available quantitative studies focused on 

comparisons of the relative GHG emissions of nuclear to coal-fired generation. The quantitative 

estimates of the GHG emissions associated with the nuclear fuel cycle (and, in some cases, the 

nuclear lifecycle), as compared to an equivalent coal-fired plant, are presented in Table 6–2. 

The NRC staff considered the best available information for its independent analysis. Although 

the following chart does not include all existing studies, it gives an illustrative range of estimates 

developed by various sources.

Table 6–2. Nuclear Greenhouse Gas Emissions Compared to Coal

Source GHG Emission Results

Mortimer (1990) Nuclear—230,000 tons CO2

(a)

Coal—5,912,000 tons CO2

Note: Future GHG emissions from nuclear to increase because of 

declining ore grade.

Andseta et al. (1998) Nuclear energy produces 1.4% of the GHG emissions compared to coal.

Note: Future reprocessing and use of nuclear-generated electrical 

power in the mining and enrichment steps are likely to change the 

projections of earlier authors, such as Mortimer (1990).

Spadaro (2000) Nuclear—2.5–5.7 g Ceq/kWh

Coal—264–357 g Ceq/kWh

Fritsche (2006) (Values 

estimated from graph in 

Figure 4)

Nuclear—33 g Ceq/kWh

Coal—950 g Ceq/kWh
Environmental Impacts of the Uranium Fuel Cycle, 

Waste Management, and Greenhouse Gas Emissions

6-6 

Source GHG Emission Results

POST (2006) (Nuclear 

calculations from AEA 2006)

Nuclear—5 g Ceq/kWh

Coal—>1,000 g Ceq/kWh

Note: Decrease of uranium ore grade to 0.03% would raise nuclear to 

6.8 g Ceq/kWh. Future improved technology and carbon capture and 

storage could reduce coal-fired GHG emissions by 90%.

Weisser (2006) (Compilation of 

results from other studies)

Nuclear—2.8–24 g Ceq/kWh

Coal—950–1,250 g Ceq/kWh

(a) CO2 is carbon dioxide.

6.2.1.2 Summary of Nuclear Greenhouse Gas Emissions Compared to Natural Gas

The quantitative estimates of the GHG emissions associated with the nuclear fuel cycle (and, in 

some cases, the nuclear lifecycle), as compared to an equivalent natural gas-fired plant, are 

presented in Table 6–3. In considering the best available information for its independent 

analysis, the staff noted that the following chart does not include all existing studies; however, it 

gives an illustrative range of estimates developed by various sources.

Table 6–3. Nuclear Greenhouse Gas Emissions Compared to Natural Gas

Source GHG Emission Results

Spadaro (2000) Nuclear—2.5–5.7 g Ceq/kWh

Natural Gas—120–188 g Ceq/kWh

Storm van Leeuwen & Smith 

(2008)

Nuclear fuel cycle produces 20–33% of the GHG emissions compared 

to natural gas (at high ore grades).

Note: Future nuclear GHG emissions to increase because of declining 

ore grade.

Fritsche (2006) (Values 

estimated from graph in 

Figure 4)

Nuclear—33 g Ceq/kWh

Cogeneration Combined Cycle Natural Gas—150 g Ceq/kWh

POST (2006) (Nuclear 

calculations from AEA 2006)

Nuclear—5 g Ceq/kWh

Natural Gas—500 g Ceq/kWh

Note: Decrease of uranium ore grade to 0.03% would raise nuclear to 

6.8 g Ceq/kWh. Future improved technology and carbon capture and 

storage could reduce natural gas GHG emissions by 90%.

Weisser (2006) (Compilation of 

results from other studies)

Nuclear—2.8–24 g Ceq/kWh

Natural Gas—440–780 g Ceq/kWh

Dones (2007) Author critiqued methods and assumptions of Storm van Leeuwen and 

Smith (2005) and concluded that the nuclear fuel cycle produces 

15–27% of the GHG emissions of natural gas.

Summary of Nuclear Greenhouse Gas Emissions Compared to Renewable Energy Sources. 

The quantitative estimates of the GHG emissions associated with the nuclear fuel cycle, as 

compared to equivalent renewable energy sources, are presented in Table 6–4. Calculation of 
Environmental Impacts of the Uranium Fuel Cycle, 

Waste Management, and Greenhouse Gas Emissions

6-7 

GHG emissions associated with these sources is more difficult than the calculations for nuclear 

energy and fossil fuels because of the large variation in efficiencies due to their different 

sources and locations. For example, the efficiency of solar and wind energy is highly dependent 

on the location in which the power generation facility is installed. Similarly, the range of GHG 

emissions estimates for hydropower varies greatly, depending on the type of dam or reservoir 

involved (if used at all). Therefore, the GHG emissions estimates for these energy sources 

have a greater range of variability than the estimates for nuclear and fossil-fuel sources. As 

noted in Section 6.2.1.2, the following chart gives an illustrative range of estimates developed 

by various sources.

Table 6–4. Nuclear Greenhouse Gas Emissions Compared to 

Renewable Energy Sources

Source GHG Emission Results

Mortimer (1990) Nuclear—230,000 tons CO2

Hydropower—78,000 tons CO2

Wind power—54,000 tons CO2

Tidal power—52,500 tons CO2

Note: Future GHG emissions from nuclear are expected to increase 

because of declining ore grade.

Spadaro (2000) Nuclear—2.5–5.7 g Ceq/kWh

Solar PV—27.3–76.4 g Ceq/kWh

Hydroelectric—1.1–64.6 g Ceq/kWh

Biomass—8.4–16.6 g Ceq/kWh

Wind—2.5–13.1 g Ceq/kWh

Fritsche (2006) (Values 

estimated from graph in 

Figure 4)

Nuclear—33 g Ceq/kWh

Solar PV—125 g Ceq/kWh

Hydroelectric—50 g Ceq/kWh

Wind—20 g Ceq/kWh

POST (2006) (Nuclear 

calculations from AEA 2006)

Nuclear—5 g Ceq/kWh

Biomass—25–93 g Ceq/kWh

Solar PV—35–58 g Ceq/kWh

Wave/Tidal—25–50 g Ceq/kWh

Hydroelectric—5–30 g Ceq/kWh

Wind—4.64–5.25 g Ceq/kWh

Note: Decrease of uranium ore grade to 0.03% would raise nuclear to 

6.8 g Ceq/kWh. 

Weisser (2006) (Compilation of 

results from other studies)

Nuclear—2.8–24 g Ceq/kWh

Solar PV—43–73 g Ceq/kWh

Hydroelectric—1–34 g Ceq/kWh

Biomass—35–99 g Ceq/kWh

Wind—8–30 g Ceq/kWh

Fthenakis & Kim (2007) Nuclear—16–55 g Ceq/kWh

Solar PV—17–49 g Ceq/kWh

(a) CO2 is carbon dioxide.

Conclusion. The sampling of data presented in Table 6–2, Table 6–3, and Table 6–4

demonstrates the challenges of any attempt to determine the specific amount of GHG emission 

attributable to nuclear energy production sources, as different assumptions and calculation 
Environmental Impacts of the Uranium Fuel Cycle, 

Waste Management, and Greenhouse Gas Emissions

6-8 

methods will yield differing results. The differences and complexities in these assumptions and 

analyses will further increase when they are used to project future GHG emissions. 

Nevertheless, several conclusions can be drawn from the information presented.

First, the various studies show a general consensus that nuclear power currently produces 

fewer GHG emissions than electrical generation based on fossil fuel. For example, the GHG 

emissions from a complete nuclear fuel cycle currently range from 2.5 to 55 grams of carbon 

equivalent per Kilowatt hour (g Ceq/kWh), as compared to the use of coal plants 

(264 to 1,250 g Ceq/kWh) and natural gas plants (120 to 780 g Ceq/kWh). The studies also give 

estimates of GHG emissions from five renewable energy sources based on current technology. 

These estimates included solar-photovoltaic (17 to 125 g Ceq/kWh), hydroelectric 

(1 to 64.6 g Ceq/kWh), biomass (8.4 to 99 g Ceq/kWh), wind (2.5 to 30 g Ceq/kWh), and tidal 

(25 to 50 g Ceq/kWh). The range of these estimates is wide, but the general conclusion is that 

current GHG emissions from the nuclear fuel cycle are of the same order of magnitude as from 

these renewable energy sources.

Second, the studies show no consensus on future relative GHG emissions from nuclear power 

and other sources of electricity. There is substantial disagreement among the various authors 

about the GHG emissions associated with declining uranium ore concentrations, future uranium 

enrichment methods, and other factors, including changes in technology. Similar disagreement 

exists about future GHG emissions associated with coal and natural gas for electricity 

generation. Even the most conservative studies conclude that the nuclear fuel cycle currently 

produces fewer GHG emissions than sources based on fossil fuel and is expected to continue to 

do so in the near future. The primary difference between the authors is the projected cross-over 

date (the time at which GHG emissions from the nuclear fuel cycle exceed those sources based 

on fossil fuel) or whether cross-over will actually occur. 

Considering the current estimates and future uncertainties, it appears that GHG emissions 

associated with the proposed STP relicensing action are likely to be lower than those 

associated with energy sources based on fossil fuel. The staff bases this conclusion on the 

following rationale:

• As shown in Table 6–2 and Table 6–3, the current estimates of GHG 

emissions from the nuclear fuel cycle are far below those for energy sources

based on fossil fuel. 

• License renewal of a nuclear power plant like STP may involve continued 

GHG emissions due to uranium mining, processing, and enrichment, but will 

not result in increased GHG emissions associated with plant construction or 

decommissioning (as the plant will have to be decommissioned at some point 

whether the license is renewed or not).

• Few studies predict that nuclear fuel cycle emissions will exceed those of 

fossil fuels within a timeframe that includes the STP periods of extended 

operation. Several studies suggest that future extraction and enrichment 

methods, the potential for higher-grade resource discovery, and technology 

improvements could extend this timeframe.

With respect to comparison of GHG emissions among the proposed STP license renewal action 

and renewable energy sources, it appears likely that there will be future technology 

improvements and changes in the type of energy used for mining, processing, and constructing 

facilities of all types. Currently, the GHG emissions associated with the nuclear fuel cycle and 

renewable energy sources are within the same order of magnitude. Because nuclear fuel 
Environmental Impacts of the Uranium Fuel Cycle, 

Waste Management, and Greenhouse Gas Emissions

6-9 

production is the most significant contributor to possible future increases in GHG emissions 

from nuclear power—and because most renewable energy sources lack a fuel component—it is 

likely that GHG emissions from renewable energy sources would be lower than those 

associated with STP at some point during the period of extended operation.

The staff also supplies an additional discussion about the contribution of GHG to cumulative air 

quality impacts in Section 4.11.2 of this SEIS. 

6.3 References

10 CFR 51. Code of Federal Regulations, Title 10, Energy, Part 51, “Environmental Protection 

Regulations for Domestic Licensing and Related Regulatory Functions.”

10 CFR 54. Code of Federal Regulations, Title 10, Energy, Part 54, “Requirements for Renewal 

of Operating Licenses for Nuclear Power Plants.”

[AEA] AEA Technology. 2006. “Carbon Footprint of the Nuclear Fuel Cycle, Briefing Note.” 

East Kilbride, UK: British Energy Group. March 2006. Available at 

<http://www.british-energy.com/documents/carbon_footprint.pdf> (accessed on April 5, 2012).

Andseta S, Thompson MJ, Jarrell JP, Pendergast DR. 1998. CANDU Reactors and 

Greenhouse Gas Emissions. Proceedings of the 19th Annual Conference, Canadian Nuclear 

Society; 1998 October 18-21; Toronto, Ontario. Available at 

<http://www.computare.org/Support%20documents/Publications/Life%20Cycle.htm> (accessed 

on April 5, 2012).

Dones R. 2007. Critical Note on the Estimation by Storm Van Leeuwen JW and Smith P of the 

Energy Uses and Corresponding CO2 Emissions for the Complete Nuclear Energy Chain. 

Villigen, Switzerland: Paul Sherer Institute. April 2007. Available at 

<http://gabe.web.psi.ch/pdfs/Critical%20note%20GHG%20PSI.pdf> (accessed on 

April 5, 2012).

Fritsche UR. 2006. Comparison of Greenhouse-Gas Emissions and Abatement Cost of 

Nuclear and Alternative Energy Options from a Life-Cycle Perspective. Freiburg, Germany: 

Oko-Institut. January 2006. Available at <http://www.oeko.de/oekodoc/315/2006-017-en.pdf> 

(accessed on April 5, 2012)

Fthenakis VM, Kim HC. 2007. Greenhouse-gas emissions from solar-electric and nuclear 

power: A life cycle study. Energy Policy 35(4):2549–2557.

[IAEA] International Atomic Energy Agency. 2000. Nuclear Power for Greenhouse Gas 

Mitigation under the Kyoto Protocol: The Clean Development Mechanism (CDM). Vienna, 

Austria: IAEA. November 2000. Available at 

<http://www.iaea.org/Publications/Booklets/GreenhouseGas/greenhousegas.pdf> (accessed on 

April 5, 2012).

Mortimer N. 1990. World warms to nuclear power. SCRAM Safe Energy Journal

Dec 89/Jan 90. Available at <http://www.no2nuclearpower.org.uk/articles/mortimer_se74.php> 

(accessed on April 5, 2012).

[NEA and OECD] Nuclear Energy Agency and the Organization for Economic Co-operation and 

Development. 2002. Nuclear Energy and the Kyoto Protocol. Paris, France: OECD. Available 

at <http://www.nea.fr/ndd/reports/2002/nea3808-kyoto.pdf> (accessed on April 5, 2012).
Environmental Impacts of the Uranium Fuel Cycle, 

Waste Management, and Greenhouse Gas Emissions

6-10

[NRC] U.S. Nuclear Regulatory Commission. 1996. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. NUREG-1437, Volumes 1 and 2, Washington, DC.

[NRC] U.S. Nuclear Regulatory Commission. Code Manual for MACCS2: Volume 1, User’s 

Guide. Washington, DC. NRC. NUREG/CR–6613. May 1998. ADAMS No. ML063550020.

[NRC] U.S. Nuclear Regulatory Commission. 1999. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants, Main Report, “Section 6.3, Transportation, Table 9.1, 

Summary of Findings on NEPA Issues for License Renewal of Nuclear Power Plants, Final 

Report.” NUREG-1437, Volume 1, Addendum 1, Washington, DC.

[NRC] U.S. Nuclear Regulatory Commission. 2012a. Commission, Memorandum and Order 

CLI-12-16, ADAMS No. ML12220A094.

[NRC] U.S. Nuclear Regulatory Commission. 2012b. “SRM-COMSECY-12-0016–Approach for 

Addressing Policy Issues Resulting from Court Decision To Vacate Waste Confidence Decision 

and Rule,” ADAMS No. ML12250A032.

[POST] Parliamentary Office of Science and Technology. 2006. Carbon footprint of electricity 

generation. Postnote 268. October 2006. Available at 

<http://www.parliament.uk/documents/post/postpn268.pdf> (accessed on April 5, 2012).

Schneider M. 2000. Climate Change and Nuclear Power. Gland, Switzerland: WWF-World 

Wildlife Fund for Nature. April 2000. Available at 

<http://assets.panda.org/downloads/fullnuclearreprotwwf.pdf> (accessed on April 5, 2012).

Spadaro JV, Langlois L, Hamilton B. 2000. “Greenhouse Gas Emissions of Electricity 

Generation Chains: Assessing the Difference.” Vienna, Austria: International Atomic Energy 

Agency. Available at 

<http://www.iaea.org/Publications/Magazines/Bulletin/Bull422/article4.pdf>.

[STPNOC] STP Nuclear Operating (STPNOC). 2010. License Renewal Application, South 

Texas Project, Units 1 and 2, Appendix E, Applicant’s Environmental Report, Operating License 

Renewal Stage. ADAMS No. ML103010257.

Storm van Leeuwen JW, Smith P. 2008. Nuclear Power—The Energy Balance. Chaam, 

Netherlands: Ceedata Consultancy. February 2008. Available at <http://www.stormsmith.nl/> 

(accessed on April 5, 2012).

Weisser D. 2006. A guide to life-cycle greenhouse gas (GHG) emissions from electric supply 

technologies. Energy 32(9): 1543–1559. Available at 

<http://www.iaea.org/OurWork/ST/NE/Pess/assets/GHG_manuscript_pre-print_

versionDanielWeisser.pdf> (accessed on April 5, 2012).
7-1 

7.0 ENVIRONMENTAL IMPACTS OF DECOMMISSIONING

Environmental impacts from the activities associated with the decommissioning of any reactor 

before or at the end of an initial or renewed license are evaluated in Supplement 1 of 

NUREG-0586, Final Generic Environmental Impact Statement on Decommissioning of Nuclear 

Facilities Regarding the Decommissioning of Nuclear Power Reactors (NRC 2002). The U.S. 

Nuclear Regulatory Commission (NRC) staff’s (the staff’s) evaluation of the environmental 

impacts of decommissioning—presented in NUREG-0586, Supplement 1—notes a range of 

impacts for each environmental issue.

Additionally, the incremental environmental impacts associated with decommissioning activities 

resulting from continued plant operation during the renewal term are discussed in 

NUREG-1437, Generic Environmental Impact Statement for License Renewal of Nuclear Plants 

(GEIS) (NRC 1996, 1999). The GEIS includes a determination of whether the analysis of the 

environmental issue could be applied to all plants and whether additional mitigation measures 

would be warranted. Issues were then assigned a Category 1 or a Category 2 designation. 

Section 1.4 of this supplemental environmental impact statement (SEIS) explains the criteria for 

Category 1 and Category 2 issues and defines the impact designations of SMALL, MODERATE, 

and LARGE. The staff analyzed site-specific issues (Category 2) for South Texas Project (STP) 

and assigned them a significance level of SMALL, MODERATE, or LARGE, or not applicable to 

STP because of site characteristics or plant features. There are no Category 2 issues related to 

decommissioning.

7.1 Decommissioning

Table 7–1 lists the Category 1 issues in Table B–1 of Title 10 of the Code of Federal 

Regulations (CFR) Part 51, Subpart A, Appendix B, that are applicable to STP decommissioning 

following the renewal term.

Table 7–1. Issues Related to Decommissioning

Issues GEIS Sections Category

Radiation doses 7.3.1; 7.4 1

Waste management 7.3.2; 7.4 1

Air quality 7.3.3; 7.4 1

Water quality 7.3.4; 7.4 1

Ecological resources 7.3.5; 7.4 1

Socioeconomic impacts 7.3.7; 7.4 1

Decommissioning would occur whether STP were shut down at the end of its current operating 

license or at the end of the period of extended operation. There are no site-specific issues 

related to decommissioning.

A brief description of the staff’s review and the GEIS conclusions, as codified in Table B-1, 

10 CFR Part 51, for each of the issues follows:
Environmental Impacts of Decommissioning

7-2 

Radiation Doses. Based on information in the GEIS, the NRC noted that “[d]oses to the public 

will be well below applicable regulatory standards regardless of which decommissioning method 

is used. Occupational doses would increase no more than 1 person-rem (1 person-mSv) 

caused by buildup of long-lived radionuclides during the license renewal term.”

Waste Management. Based on information in the GEIS, the NRC noted that 

“[d]ecommissioning at the end of a 20-year license renewal period would generate no more 

solid wastes than at the end of the current license term. No increase in the quantities of 

Class C or greater than Class C wastes would be expected.”

Air Quality. Based on information in the GEIS, the NRC noted that “[a]ir quality impacts of 

decommissioning are expected to be negligible either at the end of the current operating term or 

at the end of the license renewal term.”

Water Quality. Based on information in the GEIS, the NRC noted that “[t]he potential for 

significant water quality impacts from erosion or spills is no greater whether decommissioning 

occurs after a 20-year license renewal period or after the original 40-year operation period, and 

measures are readily available to avoid such impacts.”

Ecological Resources. Based on information in the GEIS, the NRC noted that 

“[d]ecommissioning after either the initial operating period or after a 20-year license renewal 

period is not expected to have any direct ecological impacts.”

Socioeconomic Impacts. Based on information in the GEIS, the NRC noted that 

“[d]ecommissioning would have some short-term socioeconomic impacts. The impacts would 

not be increased by delaying decommissioning until the end of a 20-year relicense period, but 

they might be decreased by population and economic growth.”

The staff has not found any new and significant information during its independent review of 

South Texas Project Nuclear Operating Company’s (STPNOC’s) Environmental Report (ER) 

(STPNOC 2010), the site audit, the scoping process, or its evaluation of other available 

information (including comments on the draft SEIS). Therefore, the NRC staff concludes that 

there are no impacts related to these issues, beyond those discussed in the GEIS

(NRC 1996, 1999). For all of these issues, the NRC staff concluded in the GEIS that the 

impacts are SMALL, and additional plant-specific mitigation measures are not likely to be 

sufficiently beneficial to be warranted.

7.2 References

10 CFR 51. Code of Federal Regulations, Title 10, Energy, Part 51, “Environmental protection 

regulations for domestic licensing and related regulatory functions.”

[NRC] U.S. Nuclear Regulatory Commission. 1996. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. Washington, DC: NRC. NUREG-1437. May 1996. 

ADAMS Nos. ML040690705 and ML040690738.

[NRC] U.S. Nuclear Regulatory Commission. 1999. Section 6.3, Transportation, Table 9.1, 

Summary of findings on NEPA issues for license renewal of nuclear power plants. In: Generic 

Environmental Impact Statement for License Renewal of Nuclear Plants. Washington, DC: 

NRC. NUREG-1437, Volume 1, Addendum 1. August 1999. ADAMS No. ML04069720.

[NRC] U.S. Nuclear Regulatory Commission. 2002. Final Generic Environmental Impact 

Statement on Decomissioning of Nuclear Facilities Regarding the Decommissioning of Nuclear 
Environmental Impacts of Decommissioning

7-3 

Power Reactors. Washington, DC. NRC. NUREG-0586, Supplement 1. November 2002. 

ADAMS No. ML023470304 and ML023500295.

[STPNOC] South Texas Plant Nuclear Operating Company. 2010. “South Texas Project, 

Applicant’s Environmental Report—Operating License Renewal Stage, South Texas Project

Units 1 & 2.” September 2010. ADAMS No. ML103010263. 

8-1 

8.0 ENVIRONMENTAL IMPACTS OF ALTERNATIVES

The National Environmental Policy Act (NEPA) requires the consideration of a range of 

reasonable alternatives to the proposed action in an environmental impact statement (EIS). In 

this case, the proposed action is whether to issue renewed licenses for South Texas Project 

(STP), Units 1 and 2, which will allow the plant to operate for 20 years beyond the current 

license expiration dates. A license is just one of many authorizations that an applicant must 

obtain in order to operate its nuclear plant. Energy-planning decisionmakers and the owners of 

the nuclear power plant ultimately decide if the plant will operate. Economic and environmental 

considerations play a primary role in this decision. The U.S. Nuclear Regulatory Commission’s 

(NRC’s) responsibility is to ensure the safe operation of nuclear power facilities, not to formulate 

energy policy or encourage or discourage the development of alternative power generation (or 

replacement power alternatives). 

The license renewal process is designed to assure safe operation of the nuclear power plant 

during the license renewal term. Under the NRC’s environmental protection regulations in 

Title 10, Part 51, of the Code of Federal Regulations (10 CFR Part 51), which implement 

Section 102(2) of NEPA, renewal of a nuclear power plant operating license requires the 

preparation of an EIS.

To support the preparation of these EISs, the NRC prepared the Generic Environmental Impact 

Statement for License Renewal of Nuclear Plants (GEIS), NUREG-1437, in 1996. The license 

renewal GEIS was prepared to assess the environmental impacts of continued nuclear power 

plant operations during the license renewal term. The intent was to determine which 

environmental impacts would result in essentially the same impact at all nuclear power plants 

and which ones could result in different levels of impacts at different plants and would require a 

plant-specific analysis to determine the impacts. For those issues that could not be generically 

addressed, the NRC develops a plant-specific supplemental environmental impact statement 

(SEIS) to the GEIS.

NRC regulations in 10 CFR 51.71(d) for license renewal require that a SEIS do the following: 

Consider and weigh the environmental effects of the proposed action [license 

renewal]; the environmental impacts of alternatives to the proposed action; and 

alternatives available for reducing or avoiding adverse environmental effects.

While the GEIS reached generic conclusions regarding many environmental issues associated 

with license renewal, it did not determine which alternatives are reasonable or reach 

conclusions about site-specific environmental impact levels. As such, the NRC must evaluate 

environmental impacts of alternatives on a site-specific basis.

As stated in Chapter 1 of this SEIS, alternatives to renewing STPNOC’s operating licenses must 

meet the purpose and need for the proposed action. They must “provide an option that allows 

for power generation capability beyond the term of a current nuclear power plant operating 

license to meet future system generating needs, as such needs may be determined by State, 

utility, and, where authorized, Federal (other than NRC) [decisionmakers].”

The NRC ultimately makes no decision about which alternative (or the proposed action) to carry 

out because that decision falls to the appropriate energy-planning decisionmakers. 
Environmental Impacts of Alternatives

8-2 

Comparing the environmental effects of these 

alternatives will help the NRC decide if the adverse 

environmental impacts of license renewal are great 

enough to deny the option of license renewal for 

energy-planning decisionmakers 

(10 CFR 51.95(c)(4)). If the NRC acts to issue a 

renewed license, all of the alternatives, including the 

proposed action, will be available to energy-planning 

decisionmakers. If NRC decides not to renew the 

license (or takes no action at all), then 

energy-planning decisionmakers may no longer elect 

to continue operating STP and will have to resort to 

another alternative—which may or may not be one of 

the alternatives considered in this section—to meet 

their energy needs now being satisfied by STP.

In evaluating alternatives to license renewal, the NRC 

considered energy technologies or options currently 

in commercial operation, as well as some 

technologies not currently in commercial operation 

but likely to be commercially available by the time the 

current STP operating licenses expire. The current operating licenses for STP, Units 1 and 2, 

will expire on August 20, 2027, and December 15, 2028, respectively. The NRC’s analysis 

assumed that an alternative must be available (able to be constructed, permitted, and 

connected to the grid) by the time the current STP licenses expire.

NRC eliminated alternatives that cannot meet future system needs by providing the amounts of 

baseload power equivalent to the STP current generating capacity (2,500 megawatts electric 

(MWe)) and whose costs or benefits do not justify inclusion in the range of reasonable 

alternatives from detailed studies. NRC evaluated the remaining alternatives, which are 

discussed in-depth in this section. Each alternative eliminated from detailed study is briefly 

discussed, and a basis for its removal is provided at the end of this section. In total, 18 energy 

technology options and alternatives to the proposed action were considered (see text box) and 

then narrowed to the 5 alternatives considered in Sections 8.1 through 8.5. The no-action 

alternative is considered in Section 8.7.

The GEIS presents an overview of some energy technologies but does not reach any 

conclusions about which alternatives are most appropriate. Since 1996, many energy 

technologies have evolved significantly in capability and cost, while regulatory structures have 

changed to either promote or impede development of particular alternatives.

As a result, the analyses include updated information from the following sources:

• Energy Information Administration (EIA), 

• other offices within the Department of Energy (DOE), 

• U.S. Environmental Protection Agency (EPA), 

• Electric Reliability Council of Texas (ERCOT), 

• industry sources and publications, and 

• information submitted by the applicant in the STP Nuclear Operating 

Company’s (STPNOC) Environmental Report (ER). 

Alternatives Evaluated In-Depth:

• new nuclear, 

• natural gas-fired combined-cycle (NGCC), 

• supercritical coal, 

• combination alternative (NGCC, wind, and 

energy efficiency and conservation), and

• purchased power. 

Other Alternatives Considered: 

• offsite nuclear-, gas-, or coal- generation, 

• energy efficiency and conservation, 

• wind power, 

• solar power, 

• hydroelectric power, 

• wave and ocean energy, 

• geothermal power, 

• municipal solid waste, 

• biomass, 

• biofuels, 

• oil-fired power, 

• fuel cells, and 

• delayed retirement.
Environmental Impacts of Alternatives

8-3 

The evaluation of each alternative considers the 

environmental impacts across several impact 

categories: air quality, groundwater use and 

quality, surface water use and quality, aquatic 

resources, terrestrial resources, human health, 

land use, socioeconomics, transportation, 

aesthetics, archaeological and historic resources, 

environmental justices, and waste management. A 

three-level standard of significance—SMALL, 

MODERATE, or LARGE—is used to indicate the 

intensity of environmental effects for each 

alternative undergoing in-depth evaluation. The 

order of presentation is not meant to imply 

increasing or decreasing level of impact. Nor does 

it imply that an energy-planning decisionmaker 

would select one or another alternative.

For each alternative where it is feasible to do so, 

the NRC considers the environmental effects of 

locating the alternative at the existing STP site, as 

well as at an alternate site. Selecting the existing 

plant site allows for the maximum use of existing 

transmission and cooling system infrastructures 

and minimizes the overall environmental impact.

In addition, to ensure that the alternatives analysis was consistent with State or regional energy 

policies, the NRC reviewed energy relevant statutes, regulations, and policies. The NRC also 

considered the current generation capacity mix and electricity production data within the 

ERCOT service area, in which STP, Units 1 and 2, are located. ERCOT is one of eight regional 

reliability councils in North America and operates under the reliability and safety standards set 

by the North American Electric Reliability Council (STPNOC 2010a). ERCOT is the 

independent system operator for the electric grid for most of Texas and manages the flow of 

electric power to approximately 23 million Texas customers, representing 85 percent of the 

State’s electric load and 75 percent of the State’s land area. ERCOT is unique because it is 

located entirely within the boundaries of the State of Texas. As such, the NRC considered the 

current generation capacity mix and electricity production data within the ERCOT service area in 

the evaluation of reasonable alternatives. In 2010, electric generators in ERCOT had an 

installed generating capacity of approximately 84,400 MWe. This capacity included units fueled 

by natural gas (57 percent), coal (23 percent), wind (12 percent), nuclear (6 percent), and other 

sources (2 percent). In 2010, the electric generators in ERCOT provided approximately 

319 million megawatt-hours of electricity. Electricity produced was dominated by coal 

(40 percent) followed by natural gas (38 percent), nuclear (13 percent), wind (8 percent), and 

other sources (1 percent) (ERCOT 2011a).

Sections 8.1 through 8.5 describe the environmental impacts of alternatives to license renewal. 

These alternatives include a new nuclear generation option in Section 8.1; a new NGCC in 

Section 8.2; a new coal-fired plant in Section 8.3; a combination alternative of NGCC, wind, and 

energy conservation and efficiency in Section 8.4; and purchased power in Section 8.5. In 

Section 8.6, alternatives considered but eliminated from detailed study are briefly discussed. 

Finally, the environmental effects that may occur if the NRC takes no action and does not issue 

renewed licenses for STP are described in Section 8.7. Section 8.8 summarizes, in detail, the 

impacts of each of the alternatives considered.

Energy Outlook

Each year, the EIA—part of the DOE—issues its 

updated Annual Energy Outlook (AEO). 

AEO 2011, affirms that natural gas, renewable, 

and coal are likely to fuel most new electrical 

capacity through 2035, with some growth in 

nuclear capacity (EIA 2011a), although all 

projections are subject to future developments in 

fuel price, electrical demand, and regulatory 

changes.

“Natural gas-fired plants account for 60 percent

of capacity additions between 2010 and 2035 in 

the AEO2011 Reference case, compared with 

25 percent for renewables, 11 percent for coalfired plants, and 3 percent for nuclear. 

Escalating construction costs have the largest 

impact on capital-intensive technologies, 

including nuclear, coal, and renewables. 

However, Federal tax incentives, State energy 

programs, and rising prices for fossil fuels 

increase the competitiveness of renewable and 

nuclear capacity. In contrast, uncertainty about 

future limits on GHG [greenhouse-gas] 

emissions and other possible environmental 

regulations reduces the competitiveness of coalfired plants....” (EIA 2011a).
Environmental Impacts of Alternatives

8-4 

8.1 New Nuclear Generation

In this section, the NRC staff evaluates the environmental impacts of a new nuclear generation 

option at the STP site.

The NRC considers the construction of two new nuclear plants to be a reasonable alternative to 

STP license renewal for Units 1 and 2 because nuclear generation currently provides baseload 

power in the ERCOT region, ERCOT expects additional nuclear generation in the future, and 

the technology to provide nuclear generation is readily available (ERCOT 2011a). In addition, 

on September 30, 2007, STPNOC submitted combined license (COL) applications to construct 

and operate two new advanced boiling water reactor (ABWR) nuclear plants (Units 3 and 4) on 

the STP site (NRC 2011). In its ER for Units 3 and 4, STPNOC’s schedule included 5 years 

from when NRC issues its licenses to when commercial operations could begin 

(STPNOC 2010b). Therefore, there is sufficient time for STPNOC to prepare and submit an 

application and build and operate two new nuclear units before the licenses for Units 1 and 2 

expire in 2027 and 2028, respectively. This section presents the environmental impacts of the 

new nuclear generation alternative, which includes constructing and operating two new nuclear 

plants at the STP site.

In evaluating the new nuclear alternative, based on best available information, the NRC 

presumed that new reactors would be installed on the STP site, allowing for the maximum use 

of existing ancillary facilities such as the transmission and cooling systems. The NRC further 

presumed that the new reactors would be two ABWR reactors similar to what the NRC analyzed 

in its environmental analysis for Units 3 and 4 in its final EIS (NRC 2011). As of 

September 2012, NRC is continuing to review the STP application for Units 3 and 4. While the 

licenses have not been granted as of September 2012, the NRC staff is using the results from 

its final EIS for Units 3 and 4 because it provides a site-specific analysis of two new nuclear 

plants at the STP site.

For the purpose of this analysis, each of the two ABWR reactors would have a net electrical 

output of approximately 1,300 MWe, which is slightly more than the generating capacity 

(2,500-MWe capacity) of STP, Units 1 and 2 (STPNOC 2010a). STPNOC (2010a) estimated 

that the power block and ancillary facilities (excluding the cooling-water system) for the new 

reactors would require approximately 540 ac (219 ha) and that sufficient contiguous acreage 

was available on the STP site. Because the heat-rejection demands are similar for Units 1 

and 2 and proposed Units 3 and 4, the NRC estimated that the existing cooling system—

including the existing intake and discharge structures on the main cooling reservoir (MCR) and 

the Colorado River—would meet the heat-rejection demands of the two new reactors without 

any modifications. In STPNOC’s ER for Units 3 and 4, STPNOC assumed minor modifications 

would be required to increase operations from two units to four units at the STP site. For the 

purposes of this analysis, the two new reactors would replace Units 1 and 2 rather than add two 

new units to the site; therefore, it is unlikely that modification would be required. Construction 

materials would be delivered via rail, truck, or barge. To accommodate such shipments, 

STPNOC would need to dredge near the current barge slip, and the rail spur would require 

upgrades (STPNOC 2010b).

NRC assumed that construction of two new nuclear units at the STP site would generally follow 

the same timeframe as that described in STPNOC’s ER for the construction of Units 3 and 4. 

This schedule included 12 months for site preparation, 45 months after NRC issues the licenses 

to complete construction and fuel loading, 6 months from fuel loading to initial power generation 

for Unit 3, and an additional 12 months for Unit 4 (STPNOC 2010b).
Environmental Impacts of Alternatives

8-5 

The NRC also considered the installation of multiple small and modular reactors at the STP site 

as an alternative to renewing the licenses for STP, Units 1 and 2. NRC established the 

Advanced Reactor Program in the Office of New Reactors due to considerable interest in small 

and modular reactors along with anticipated license applications by vendors. As of 

September 2012 (based on best available information), NRC has not received any applications. 

Because there are no applications to construct and operate small modular reactors on a 

commercial scale, this analysis focused on nuclear generation by larger nuclear units.

8.1.1 Air Quality

As discussed in Section 2.2.2.1, the STP site is located in central Matagorda County, Texas, at 

the southern edge of the Metropolitan Houston-Galveston Intrastate Air Quality Control Region 

(40 CFR 81.38). The Corpus Christi-Victoria Intrastate Air Quality Control Region 

(40 CFR 81.136) lies immediately south and west of Matagorda County. EPA has designated 

all of the counties in these Air Quality Control Regions adjacent to the STP site as in compliance 

with the National Ambient Air Quality Standards (40 CFR 81.344) except Brazoria County to the 

north; Brazoria County is classified Nonattainment/Severe relative to the 8-hour ozone standard 

(EPA 2011b). 

Construction activities would cause some localized temporary air effects as a result of 

equipment emissions and fugitive dust from the operation of the earth-moving and 

material-handling equipment. Emissions from workers’ vehicles and motorized construction 

equipment exhaust would be temporary. Construction crews would use dust-control practices to 

control and reduce fugitive dust, as proposed for Units 3 and 4 (STPNOC 2010b), and because 

§111.145 of the Texas Commission for Environmental Quality’s (TCEQ) regulations require dust 

suppression control during the construction of facilities and parking lots.

During operations, two new nuclear plants would have similar air emissions to those of existing 

STP, Units 1 and 2, and those expected from proposed Units 3 and 4; air emissions would be 

primarily from backup diesel generators. Because air emissions would be similar for the new 

nuclear plants, the NRC expects similar air permitting conditions and regulatory requirements as 

that for Units 3 and 4. In STPNOC’s ER for Units 3 and 4, STPNOC stated that “[a]ir emissions 

sources would be managed in accordance with Federal, Texas, and local air quality control laws 

and regulations.” Permitting would likely include a prevention of significant deterioration (PSD) 

review and an operating permit from TCEQ.

STPNOC estimated air emissions during the operation of Units 3 and 4 as part of its COL 

application (NRC 2011; STPNOC 2010b). The largest stationary sources of emissions would be 

from three standby diesel generators and a single combustion turbine generator, each of which 

would be operated about 4 hours per month. Table 8–1 lists the expected annual emissions 

from these sources. NRC assumed that there would be similar air emissions from two new 

nuclear units.
Environmental Impacts of Alternatives

8-6 

Table 8–1. Expected Annual Emissions from the Largest 

Stationary Sources of Emissions

Diesel Generators (lb/yr) Combustion Turbine (lb/yr)

Particulates 2,500 44

Sulfur Oxides 9,200 3,800

Carbon Monoxide 9,200 1,800

Hydrocarbons 6,100 120

Nitrogen Oxides 57,900 4,000

Source: STPNOC 2010b

The operation of nuclear power plants involves the emission of some greenhouse gases, 

primarily carbon dioxide. NRC (2011) estimated that the total carbon footprint for actual plant 

operations of Units 3 and 4 for 40 years is on the order of 650,000 metric tons (MT)

(720,000 tons) of carbon dioxide equivalent (an emissions rate of about 16,000 MT

(18,000 tons) annually, averaged over the period of operation). Periodic testing of diesel 

generators and other activities during plant operations accounts for about 60 percent of the 

total, or about 190,000 MT (210,000 tons) for each unit. Workforce transportation accounts for 

the most of the remaining 40 percent, or about 130,000 MT (140,000 tons) for each unit. 

NRC (2011) based these carbon footprint estimates on information included in Appendix I of the 

final EIS and emissions data contained in the ER for Units 3 and 4 (STPNOC 2010b). 

Equipment maintenance and measures taken to mitigate transportation impacts, such as 

properly maintained asphalt or concrete roads and appropriate speed limits (STPNOC 2010b), 

would also reduce carbon dioxide emissions, while reducing other emissions. For example, 

STPNOC (2010b) states that fugitive dust generated by the commuting workforce would be 

minimized by properly maintaining hard-surfaced access roads and setting appropriate speed 

limits.

Subpart P of 40 CFR Part 51 contains the visibility protection regulatory requirements, including 

the review of new sources to be constructed in attainment or unclassified areas and that may 

affect visibility in any Federal Class I area. If a new nuclear plant were located close to a 

mandatory Class I area, additional air pollution control requirements may be required. As noted 

in Section 2.2.2.1, there are no Mandatory Class I Federal areas within 100 mi (161 km) of the 

STP site where visibility is an important value.

Because construction and operations of two new nuclear units at the STP site would not 

noticeably alter air quality, air quality impacts would be SMALL.

8.1.2 Surface Water Resources

The NRC presumes that two new nuclear units would be designed to maximize use of existing 

facilities, including the existing intake and discharge structures on the MCR and the Colorado 

River. STPNOC did not propose using any surface water during the construction of Units 3 

and 4 (NRC 2011); therefore, NRC expects that none would be used during construction for the 

new nuclear alternative.

Impacts to surface water quality could result from dredging activities in the Colorado River near 

the reservoir makeup pumping facility (RMPF) and the barge slip. Dredging can disturb 

sediments and potentially increase turbidity near and downstream of the dredged site. The 

NRC staff (NRC 2011) determined that the hydrological alterations resulting from site 

development would be localized and temporary. Permits and certifications from the U.S. Army 
Environmental Impacts of Alternatives

8-7 

Corps of Engineers (USACE) and other agencies would require the implementation of best 

management practices (BMPs) to minimize impacts.

Runoff from construction areas would be controlled under a State-issued Texas Pollutant 

Discharge Elimination System (TPDES) general permit that would require implementation of a 

stormwater pollution prevention plan and associated BMPs to prevent or significantly mitigate 

soil erosion and contamination of stormwater runoff from construction activities. Runoff from 

construction areas would be limited to the duration of the construction.

During normal operations, STPNOC would intermittently withdraw and discharge water from and 

to the Colorado River to maintain the water quality and quantity in the MCR (NRC 2011). This 

would continue to occur in accordance with STPNOC’s existing water rights and a new or 

revised State-issued TPDES permit, respectively, under this alternative. Water use would be 

similar to that of Units 1 and 2. The NRC staff (NRC 2011) estimated current water use for 

Units 1 and 2 during normal operations to be 3 percent of Texas Water Development Board 

(TWDB)-estimated Region K water supplies in 2010 (TWDB 2007). Therefore, the impact on 

surface water use in the Colorado River basin would be minimal.

In consideration of the information above, the impacts on surface water use and quality from 

construction and operations under the new nuclear generation alternative would be SMALL.

8.1.3 Groundwater Resources

The NRC presumes that the two new nuclear units would use existing ancillary facilities at the 

STP site, including use of the onsite groundwater production wells. To build Units 3 and 4, 

STPNOC (2010b) proposed withdrawing groundwater from the Deep Aquifer during 

construction. The NRC staff (NRC 2011) determined that STPNOC’s projected drawdown 

during building activities and the current presence of a sufficient confining head would maintain 

the Deep Aquifer as a confined aquifer. For construction of the new nuclear units under this 

alternative, it is assumed that STPNOC’s existing wells would be used to supply the relatively 

small amounts of water (i.e., up to 491 gpm (1,860 L/min)) required for potable and sanitary 

uses, concrete production, dust suppression and soil compaction, and other uses during 

construction of the new units (NRC 2011).

Excavation for the new reactor foundations could extend to depths of approximately 70 ft (21 m) 

below ground surface (BGS), and dewatering of the Upper and Lower Shallow Chicot aquifers 

would be required. However, slurry walls and wells were proposed for use to minimize potential 

adverse effects from dewatering both on site and off site (NRC 2011). Further, application of 

BMPs in accordance with a State-issued National Pollutant Discharge Elimination System 

(NPDES) general permit, including appropriate waste management and spill prevention 

practices, would prevent or minimize any groundwater quality impacts during construction.

During operations of Units 3 and 4, STPNOC proposed to use groundwater for power block 

operational uses, fire protection systems, and potable and sanitary systems, and to use the 

existing onsite groundwater production wells at STP. However, one or more additional wells 

could also be installed to decrease pumping rates at existing wells and to better distribute 

drawdown impacts in the Deep Aquifer and ensure sufficient withdrawal capacity under 

STPNOC’s existing groundwater permit (NRC 2011). Groundwater use for operation of the two 

replacement units was presumed to be somewhat higher than for existing STP, Units 1 and 2, 

but well within the groundwater operating permit held by STPNOC. The groundwater operating 

permit issued by the Coast Plains Groundwater Conservation District (see Section 2.1.7.2) is for 

approximately 1,860 gpm (7,040 L/min); STP, Units 1 and 2, use approximately 768 gpm 

(2,910 L/min) of groundwater; and the new units would require approximately 975 gpm 

(3,690 L/min) under normal operating conditions (NRC 2011). The NRC concludes that 
Environmental Impacts of Alternatives

8-8 

groundwater use and quality impacts are likely to be similar to those observed for STP, Units 1 

and 2.

Based on this information, the overall impact on groundwater use and quality from construction 

and operations under the new nuclear generation alternative would be SMALL.

8.1.4 Aquatic Ecology

The NRC presumed that two new nuclear units would be designed to maximize use of existing 

facilities, including the existing intake and discharge structures on the MCR and the Colorado 

River.

Construction activities for two new reactors (such as construction of heavy haul roads and the 

power blocks) could affect drainage areas or other onsite aquatic features due to site runoff. 

NRC assumed that STPNOC would install temporary and permanent erosion and sediment 

control measures to minimize the flow of disturbed soils into ditches and wetlands. Such BMPs 

would likely be described in a Texas Pollutant Discharge Elimination System (TPDES) general 

permit relating to stormwater discharges for construction activities.

To bring new materials to the site, NRC assumed construction crews would dredge near the 

barge slip on the Colorado River to transport some materials using barges, which are activities 

that STPNOC (2010b) proposed for the construction of Units 3 and 4. Permits and certifications 

from the USACE and other agencies would require the implementation of BMPs to minimize 

impacts. NRC (2011) determined that such activities would be temporary and unlikely to cause 

noticeable impacts to aquatic resources.

Plant operators would withdraw water from the Colorado River to maintain the proper water 

quality and quantity in the MCR during operations of two new ABWR units. Aquatic organisms 

would be impinged and entrained as water is drawn through the RMPF. Biota most vulnerable 

to entrainment and impingement would be the same as those described in Section 4.5 during 

the period of continued operations for Units 1 and 2. The low approach velocity at the RMPF 

(less than or equal to approximately 0.5 ft/s), the use of a pond-based heat-dissipation cooling 

system, the population status of biota most likely to be impinged and entrained, and the 

reproductive potential of fish and shellfish most vulnerable to impingement and entrainment 

would result in minimal adverse impacts to the aquatic ecosystem in the Colorado River near 

STP. 

Plant operators would discharge water from the MCR to the Colorado River to maintain water 

quality within the MCR. Discharge impacts would be similar to those described in Section 4.5 

for continued operations of STP, Units 1 and 2. Discharges are unlikely to noticeably impact 

aquatic resources near STP for the following reasons:

• STPNOC’s TPDES permit would limit the amount and timing of discharges. 

• Modeling studies indicate that mobile aquatic species could avoid the thermal 

plume by swimming at a lower depth or different side of the river (NRC 2011). 

• Species or life-stages that are less mobile organisms would not be able to 

swim away to avoid the thermal plume, such as eggs, larvae, and mollusks. 

However, most species observed in this area generally have high fecundity, 

and the number of organisms lost would be insignificant compared to their 

population in the lower Colorado River. 
Environmental Impacts of Alternatives

8-9 

• Cooling water would not be regularly discharged into the Colorado River 

because STP uses a cooling pond-based heat-dissipation system that reuses 

water from the MCR.

The NRC staff determined that the impacts to aquatic resources on the STP site and in the 

Colorado River would be SMALL because modifications on site and to the river, such as 

dredging, would be temporary, and impingement, entrainment, and heat shock would not 

noticeably impact aquatic resources.

8.1.5 Terrestrial Ecology

STPNOC (2010a) estimated that the power block and ancillary facilities (excluding the 

cooling-water system) for the new reactors would require approximately 540 ac (219 ha). 

Construction activities, such as building the heavy haul road and new facilities, would 

permanently convert approximately 300 ac (121 ha) (STPNOC 2010b). Construction would 

likely affect a variety of habitats and land uses, including industrial land (buildings, parking 

areas, and mowed-maintained fields), drainage ditches, scattered small palustrine wetlands, 

scrub-shrub habitat, and mixed grassland habitat where abandoned farm lands previously 

existed prior to construction of Units 1 and 2 (NRC 2011; STPNOC 2010b). Most of these areas 

have been mildly to extensively disturbed during the construction and operations of Units 1 

and 2 and other human activities. After the completion of the new units, plant operators would 

likely grade, landscape, and replant the areas used for temporary building support 

(STPNOC 2010b). The majority of permanently affected areas would be maintained land 

(e.g., mowed) or other industrial areas. NRC (2011) determined that the change in habitat 

availability would unlikely increase fragmentation of onsite habitats available for wildlife. 

STPNOC would likely implement BMPs to minimize impacts to wetlands. STPNOC would be 

required to comply with the USACE 404 permits (NRC 2011).

Construction activities could also adversely affect onsite wildlife through noise, increased light 

pollution, and increased traffic. However, NRC (2011) determined that these impacts would be 

temporary and minor.

STPNOC (2010b) did not observe Federally or State-listed threatened or endangered species, 

critical habitat, or suitable habitats in the proposed disturbance area for Units 3 and 4. 

NRC (2011) determined that the impacts to special status species from the construction and 

operation of Units 3 and 4 would be negligible.

Because many construction-related impacts would be temporary, and because the majority of 

long-term construction impacts would occur within previously disturbed areas, impacts on 

terrestrial resources would be SMALL.

8.1.6 Human Health

The human health effects from two new nuclear power plants would be similar to those of the 

existing STP, Units 1 and 2, and the proposed Units 3 and 4 (NRC 2011). Human health issues 

related to construction would be equivalent to those associated with the construction of any 

major complex industrial facility and would be controlled to acceptable levels through the 

application of BMPs and STPNOC’s compliance with Federal and State worker protection 

regulations. Human health impacts from operation of the new nuclear reactors would be 

equivalent to those associated with continued operation of the existing reactors and the 

proposed Units 3 and 4 (NRC 2011).

Both continuous and intermittent noise impacts can be expected at offsite locations, including at 

the closest residences. However, confining noise-producing activities to core hours of the day 
Environmental Impacts of Alternatives

8-10

(7:00 a.m. to 6:00 p.m.) and notifying potentially affected parties beforehand of such events 

would control noise impacts to acceptable levels. Noise impacts would be of short duration and 

would be SMALL.

Based on the above information, human health impacts for the construction and operation of 

two new nuclear units would be SMALL.

8.1.7 Land Use

The GEIS generically evaluates the impacts of constructing and operating various replacement 

power plant alternatives on land use, both on and off each plant site. The analysis of land use 

impacts focuses on the amount of land area that would be affected by the construction and 

operation of a new nuclear power plant at the STP site.

STPNOC (2010a) estimated that the power block and ancillary facilities (excluding the 

cooling-water system) for the two new reactors would require approximately 540 ac (219 ha) 

and that sufficient contiguous acreage was available on the STP site. A sufficient amount of 

land is available on site, and most of the area is already in industrial use. Therefore, onsite land 

use impacts from the construction and operation of two new reactors at the STP site would be 

SMALL. 

The amount of land required to mine uranium and fabricate nuclear fuel to support the new 

nuclear alternative would be similar to the amount of land required to support STP, Units 1 

and 2, although an additional amount of land would be required to support uranium fuel 

requirements during the license renewal term. According to GEIS estimates, approximately 

2,560 ac (1,036 ha) would be needed for the mining and processing of uranium fuel during the 

operating life of the new nuclear plant. Overall, offsite land use impacts from two new nuclear 

reactors would be SMALL.

8.1.8 Socioeconomics

Socioeconomic impacts are defined in terms of changes to the demographic and economic 

characteristics and social conditions of a region. For example, the number of jobs created by 

the construction and operation of a power plant could affect regional employment, income, and 

expenditures.

Two types of jobs would be created by this alternative: (1) construction jobs, which are 

transient, short in duration, and less likely to have a long-term socioeconomic impact; and 

(2) power plant operation jobs, which have the greater potential for permanent, long-term 

socioeconomic impacts. Workforce requirements for the construction and operation of the new 

nuclear generation alternative were evaluated to measure their possible effects on current 

socioeconomic conditions. 

STPNOC estimated a construction workforce of up to 5,950 (maximum) workers would be 

required to build Units 3 and 4 at the STP site (STPNOC 2010b). The relative economic 

impacts of this many workers on the local economy and tax base would vary, with the greatest 

impacts occurring in the communities where the majority of construction workers would reside 

and spend their income. As a result, local communities could experience a short-term economic 

“boom” from increased tax revenue and income generated by construction expenditures and the 

increased demand for temporary (rental) housing and business services. Some construction 

workers could relocate to Matagorda and surrounding counties in order to be closer to the 

construction work site. However, given the proximity of STP to the Houston metropolitan area, 

many construction workers could commute to the STP site, thereby lessening the need for 
Environmental Impacts of Alternatives

8-11

additional rental housing near STP. After completing the installation of the two new reactor 

units, local communities could experience a return to pre-construction economic conditions. 

Based on this information, and given the magnitude of the estimated number of workers, 

socioeconomic impacts during construction in communities near the STP site could range from 

SMALL to LARGE.

STPNOC also estimated that STP, Units 3 and 4, would require 733 operations workers and an 

additional 1,100 workers during refueling outages (STPNOC 2010b). The number of operation 

workers would include some of the 1,378 workers from STP, Units 1 and 2. Socioeconomic 

impacts during operations could range from SMALL to MODERATE as the STP site transitions 

to the new reactor units. The potential reduction in overall employment at STP could affect 

property tax revenue and income in local communities and businesses. In addition, the 

permanent housing market could also experience increased vacancies and decreased prices if 

operations workers and their families move out of the region. 

8.1.9 Transportation

Transportation impacts associated with the construction and operation of a new two-unit nuclear 

power plant would consist of commuting workers and truck deliveries of construction materials 

and equipment to the power plant site. During periods of peak construction activity, up to 

5,950 workers could be commuting daily to the STP site (STPNOC 2010b). Workers 

commuting to the STP site would primarily use two-lane roads. The volume of traffic on these 

roads, and especially Farm-to-Market (FM) 521, would increase substantially. In addition to 

commuting workers, trucks would be transporting construction materials and equipment to the 

worksite, further increasing the amount of traffic on local roads. The increase in vehicular traffic 

would peak during shift changes, resulting in temporary levels of service impacts and delays at 

intersections. Some power plant components and materials could also be delivered by train or 

barge (STPNOC 2010a). Train deliveries could cause additional traffic delays at railroad 

crossings. Based on this information, traffic-related transportation impacts during construction

could range from MODERATE to LARGE. 

Traffic-related transportation impacts would be greatly reduced after completing the installation 

of the two new reactor units. Transportation impacts would include daily commuting by the 

operating workforce, equipment and materials deliveries, and the removal of commercial waste 

material to offsite disposal or recycling facilities by truck. During reactor operations, the 

estimated number of operations workers commuting to and from STP would be 733 workers 

(STPNOC 2010b). Traffic-related transportation impacts would be less than current operations 

because the new units would employ approximately half as many workers as STP, Units 1 

and 2. However, overall transportation impacts (related to plant operating workers and potential 

Units 1 and 2 decommissioning workers) would range from SMALL to MODERATE during 

power plant operations.

8.1.10 Aesthetics

The analysis of aesthetic impacts focuses on the degree of contrast between the new nuclear 

alternative and the surrounding landscape and the visibility of the new power plant. The new 

power block would look very similar to the STP, Units 1 and 2, power block.

During construction, all of the clearing and excavation would occur on the STP site. These 

activities may be visible from offsite roads, particularly FM 521. Since the STP site already 

appears industrial, construction of the new units would appear similar to onsite activities during 

refueling outages.
Environmental Impacts of Alternatives

8-12

During reactor operations, the visual appearance of the STP site would not change since the 

power block for the new nuclear reactors would look virtually identical to the existing STP, 

Units 1 and 2, power block. Adding two new reactor units would increase the overall size of the 

existing STP facility if STP, Units 1 and 2, remained. Given the industrial appearance of the 

STP site and the similarity of the new units to the existing units, the new reactor units would 

blend in with the surroundings. In addition, the amount of noise generated during reactor 

operations would be the same as those generated during STP, Units 1 and 2, operations, which 

consists predominantly of the noise from routine industrial processes and communications. In 

general, aesthetic changes would be limited to the immediate vicinity of the STP site, and any 

impacts would be SMALL. 

8.1.11 Historic and Archaeological Resources

Cultural resources are the indications of human occupation and use of the landscape, as 

defined and protected by a series of Federal laws, regulations, and guidelines. Prehistoric 

resources are physical remains of human activities that predate written records; they generally 

consist of artifacts that may alone or collectively yield information about the past. Historic 

resources consist of physical remains that postdate the emergence of written records; in the 

U.S., they are architectural structures or districts, archaeological objects, and archaeological 

features dating from 1492 and later. Ordinarily, sites less than 50 years old are not considered 

historic, but exceptions can be made for such properties if they are of particular importance, 

such as structures associated with the development of nuclear power (e.g., Shippingport Atomic 

Power Station) or Cold War themes. American Indian resources are sites, areas, and materials 

important to American Indians for religious or heritage reasons. Such resources may include 

geographic features, plants, animals, cemeteries, battlefields, trails, and environmental features. 

The cultural resource analysis encompassed the power plant site and adjacent areas that could 

potentially be disturbed by the construction and operation of replacement plant alternatives. 

The potential for historic and archaeological resources can vary greatly depending on the 

location of the proposed site. To consider a project’s effects on historic and archaeological 

resources, any affected areas would need to be surveyed to identify and record historic and 

archaeological resources, identify cultural resources (e.g., traditional cultural properties), and 

develop possible mitigation measures to address any adverse effects from ground-disturbing 

activities.

As described in Section 2.2.10, much of the STP site has been previously disturbed by the 

construction of STP, Units 1 and 2. In addition, in preparation for the COL application for 

Units 3 and 4, STPNOC conducted a cultural resources assessment of the STP site. STPNOC 

reviewed existing information for the STP site and the area within a 10-mi (16-km) radius. 

STPNOC concluded that any cultural resource sites that may have existed on site would no 

longer retain their integrity because the area was heavily disturbed during the construction of 

Units 1 and 2 (STPNOC 2010b). In December 2006, STPNOC reported these findings to the 

SHPO at the Texas Historical Commission. The SHPO concurred that there would be no 

impacts to historic properties in January 2007 (STPNOC 2006; THC 2007).

There is a low potential for cultural resources to be located in previously undisturbed portions of 

the STP site. However, if the new nuclear units were to be sited within undisturbed areas or 

within areas of known cultural sensitivity (historic grave site located on the property and 

described in Section 2.2.10), these areas would need to be surveyed by a professional 

archaeologist to identify and develop possible mitigation measures to address any adverse 

effects from project activities. NRC assumes STPNOC would follow similar procedures to those 

described in the final EIS for STP, Units 3 and 4, if any historic or cultural resources were 

discovered during ground-disturbing activities associated with building the new units 
Environmental Impacts of Alternatives

8-13

(NRC 2011). In the final EIS for STP, Units 3 and 4, the staff concludes that the cumulative 

impacts to historic and archaeological resource would be SMALL.

The NRC staff determined that the impact of new nuclear plants at the STP site on historic and 

archaeological resources would be SMALL for the following reasons:

• NRC (2011) and STPNOC (2010a, 2010b) did not identify any cultural 

resources that could be affected by Units 3 and 4. 

• The SHPO determined that construction for Units 3 and 4 would not affect 

cultural and historic resources. 

• STPNOC has established environmental compliance procedures for new 

ground-disturbing activities.

8.1.12 Environmental Justice

The environmental justice impact analysis evaluates the potential for disproportionately high and 

adverse human health and environmental effects on minority and low-income populations that 

could result from the construction and operation of a new power plant. Adverse health effects 

are measured in terms of the risk and rate of fatal or nonfatal adverse impacts on human health. 

Disproportionately high and adverse human health effects occur when the risk or rate of 

exposure to an environmental hazard for a minority or low-income population is significant and 

exceeds the risk or exposure rate for the general population or for another appropriate 

comparison group. Disproportionately high environmental effects refer to impacts or risk of 

impact on the natural or physical environment in a minority or low-income community that are 

significant and appreciably exceed the environmental impact on the larger community. Such 

effects may include biological, cultural, economic, or social impacts. Some of these potential 

effects have been identified in resource areas discussed in this SEIS. For example, increased 

demand for rental housing during power plant construction could disproportionately affect 

low-income populations. Minority and low-income populations are subsets of the general public 

living near the STP site, and all are exposed to the same hazards generated from constructing 

and operating two new nuclear plants. Section 4.9.7, “Environmental Justice,” presents 

demographic information about minority and low-income populations residing in the vicinity of 

the STP site. 

Potential impacts to minority and low-income populations from the construction and operation of 

a new nuclear power plant at the STP site would mostly consist of environmental and 

socioeconomic effects (e.g., noise, dust, traffic, employment, and housing impacts). Noise and 

dust impacts during construction would be short-term and primarily limited to onsite activities. 

Minority and low-income populations residing along site access roads would be directly affected 

by increased commuter vehicle and truck traffic. However, because of the temporary nature of 

construction, these effects would only occur at certain hours of the day and are unlikely to be 

high and adverse. Increased demand for rental housing during construction could also affect 

low-income populations living near STP. However, given the proximity of STP to the Houston 

metropolitan area, many construction workers could commute to the STP site, thereby lessening 

the need for additional rental housing.

Based on this information, and the analysis of human health and environmental impacts 

presented in this SEIS, the construction and operation of a new nuclear power plant would not 

have disproportionately high and adverse human health and environmental effects on minority 

and low-income populations residing in the vicinity of the STP site. 
Environmental Impacts of Alternatives

8-14

8.1.13 Waste Management

During the construction stage of the new nuclear plants, land clearing and other construction 

activities would generate waste that could be recycled, disposed of on site, or shipped to an 

offsite waste disposal facility. Because the new nuclear plants would be constructed on the 

previously disturbed STP site, the amounts of waste produced during land clearing would be 

reduced. 

During the operational stage, normal plant operations, routine plant maintenance, and cleaning 

activities would generate nonradioactive waste as well as mixed waste, low-level waste, and 

high-level waste. Quantities of nonradioactive waste (discussed in Section 2.3.1 of this SEIS) 

and radioactive waste (discussed in Section 6.1 of this SEIS) generated by Units 1 and 2 would 

be comparable to that generated by the new nuclear plants.

According to the GEIS (NRC 1996), the generation and management of solid nonradioactive 

and radioactive waste during the period of renewed licenses are not expected to result in 

significant environmental impacts. Two new nuclear plants would generate waste streams 

similar to the two existing nuclear plants. Based on this information, waste impacts would be 

SMALL for two new nuclear plants located at the STP site.

8.1.14 Summary of Impacts of New Nuclear Generation

Table 8–2 summarizes the environmental impacts of the new nuclear alternative compared to 

continued operation of STP.

Table 8–2. Summary of Environmental Impacts of the New Nuclear Alternative

Compared to Continued Operation of STP, Units 1 and 2

Category New Nuclear Generation

(proposed infrastructure)

Continued STP Operation

Air quality SMALL SMALL

Surface water SMALL SMALL

Groundwater SMALL SMALL

Aquatic resources SMALL SMALL

Terrestrial resources SMALL SMALL

Human health SMALL SMALL to MODERATE

Land use SMALL SMALL

Socioeconomics SMALL to LARGE SMALL

Transportation MODERATE to LARGE SMALL

Aesthetics SMALL SMALL

Historic & archaeological SMALL SMALL

Waste management SMALL SMALL

8.2 Natural Gas-Fired Combined-Cycle Generation

In this section, the NRC staff evaluates the environmental impacts of natural gas-fired 

combined-cycle (NGCC) generation at the STP site.
Environmental Impacts of Alternatives

8-15

Natural gas accounted for 38 percent of all electricity generated in the ERCOT service area in 

2010, accounting for the second greatest share of electrical power (ERCOT 2011a). 

Development of new natural gas-fired plants may be affected by perceived or actual action to 

limit greenhouse gas emissions, although they produce markedly fewer greenhouse gases per 

unit of electrical output than coal-fired plants. Natural gas-fired plants are a feasible,

commercially available option for providing electrical generating capacity beyond STPNOC’s 

current license expiration. NRC examined NGCC because NGCC can operate with high 

thermal efficiency (approximately 60 percent for some units) and is capable of economically 

providing baseload power. Therefore, NRC considered NGCC generation a reasonable 

alternative to STP license renewal.

NGCC plants differ significantly from coal-fired boilers and existing nuclear plants. NGCC 

plants derive the majority of their electrical output from a gas-turbine cycle and then generate 

additional power—without burning any additional fuel—through a second, steam-turbine cycle. 

The first gas turbine stage (similar to a large jet engine) burns natural gas, which turns a 

driveshaft that powers an electric generator. The exhaust gas from the gas turbine is still hot 

enough to boil water to steam. Ducts carry the hot exhaust to a heat-recovery steam generator, 

which produces steam to drive a steam turbine and produce additional electrical power. The 

combined-cycle approach is significantly more efficient than any one cycle on its own; thermal 

efficiency can exceed 60 percent. Because the NGCC alternative derives much of its power 

from a gas turbine cycle, and because it wastes less heat than the existing STP units, it requires 

significantly less cooling water than the coal-fired alternative or the existing STP.

To replace the 2,500 MWe power that STP generates, NRC considered four hypothetical 

gas-fired units, each with a net capacity of 640 MWe. For purposes of this analysis, the 

hypothetical units would be similar to General Electric’s (GE’s) H-class gas fired combined-cycle 

units. While any number of commercially available combined-cycle units could be installed in a 

variety of combinations to replace the power currently produced by STP, GE’s H-class units are 

highly efficient models that would be used to minimize environmental impacts. Other 

manufacturers, like Siemens, offer similarly high efficiency models.

GE’s H-class combined-cycle generating units operate at a heat rate of 5,690 British thermal 

units per kilowatt hours (BTU/kWh), or nearly 60 percent thermal efficiency (GE 2011). As 

noted above, this NGCC alternative would require much less cooling water than STP because 

the NGCC units operate at a higher thermal efficiency and because they require much less 

water for steam cycle condenser cooling. Therefore, the NRC staff assumed that the existing 

cooling water system, including the intakes and discharges on the MCR and the Colorado River, 

would be sufficient for this alternative.

Construction of onsite visible structures would include the natural gas turbine buildings and 

heat-recovery steam generators (which may be enclosed in a single building), exhaust stacks, 

and, if necessary, equipment associated with a natural gas pipeline, such as a compressor 

station. The NGCC alternative at the STP site would use the existing STP transmission system. 

Based on GEIS estimates, the plant would require approximately 312 ac (126 ha), which 

includes a new pipeline that would run approximately 2 mi (3 km) from the STP site to an 

existing pipeline.

This 2,560 MWe NGCC plant would consume 110 billion cubic feet (ft3

) (3,111 million cubic 

meters (m3

)) of natural gas annually, assuming an average heat content of 1,029 BTU/ft3

(EIA 2009). Natural gas would be extracted from the ground through wells, then treated to 

remove impurities (like hydrogen sulfide), and blended to meet pipeline gas standards before 

being piped through the state pipeline system to the plant site. This NGCC alternative would 
Environmental Impacts of Alternatives

8-16

produce relatively little waste, primarily in the form of spent catalysts used for emissions 

controls.

To build the NGCC plant, site crews would clear vegetation from the site, prepare the site 

surface, and begin excavation before other crews begin actual construction on the plant or any 

associated infrastructure, including the 2 mi (3 km) pipeline. The NGCC alternative at the STP 

site would use the existing STP transmission system. Construction materials would be 

delivered via rail spur, truck, or barge. For the proposed construction of Units 3 and 4, 

STPNOC proposed dredging near the current barge slip and upgrading the existing rail spur to 

accommodate shipments of construction materials (STPNOC 2010b). The NRC staff finds this 

to be reasonable and assumed that dredging and rail spur upgrades would be required for the 

NGCC alternative.

8.2.1 Air Quality

As discussed in Section 2.2.2.1, the STP site is located in central Matagorda County, Texas, at 

the southern edge of the Metropolitan Houston-Galveston Intrastate Air Quality Control Region 

(40 CFR 81.38). The Corpus Christi-Victoria Intrastate Air Quality Control Region 

(40 CFR 81.136) lies immediately south and west of Matagorda County. EPA has designated 

all of the counties in these Air Quality Control Regions adjacent to the STP site as in compliance 

with the National Ambient Air Quality Standards (40 CFR 81.344) except Brazoria County to the 

north; Brazoria County is classified Nonattainment/Severe relative to the 8-hour ozone standard 

(EPA 2011b). 

Construction activities would cause some localized temporary air quality effects because of 

emissions and fugitive dust from operation of earth-moving and material-handling equipment. 

Emissions from workers’ vehicles and motorized construction equipment would be temporary. 

NRC assumed that construction crews would use dust-control practices to control and reduce 

fugitive dust. STPNOC proposed such activities during construction of proposed Units 3 and 4 

(STPNOC 2010b), and §111.145 of TCEQ’s regulations require dust suppression control during 

the construction of facilities and parking lots.

A new NGCC plant would qualify as a new major-emitting industrial facility and would be subject 

to PSD requirements under the Clean Air Act (CAA) (EPA 2011c). The NGCC plant would need 

to comply with the standards of performance for electric utility steam generating units set forth in 

40 CFR Part 60 Subpart KKKK. The plant would also require an operating permit from TCEQ. 

In STPNOC’s ER for Units 3 and 4, STPNOC stated that “[a]ir emissions sources would be 

managed in accordance with Federal, Texas, and local air quality control laws and regulations.” 

Likewise, NRC assumed that the NGCC plant would also operate in accordance with Federal, 

Texas, and local air quality control laws and regulations.

Subpart P of 40 CFR Part 51 contains the visibility protection regulatory requirements, including 

the review of new sources that would be constructed in the attainment or unclassified areas and 

may affect visibility in any Federal Class I area. If an NGCC alternative was located close to a 

mandatory Class I area, additional air pollution control requirements would be required. As 

noted in Section 2.2.2.1, there are no mandatory Class I Federal areas within 50 mi of the STP 

site.

The NRC projects the following emissions based on data published by the EIA, EPA, and on 

performance characteristics and emissions controls:

• sulfur oxides—192 tons (174 MT) per year, 

• nitrogen oxides—839 tons (761 MT) per year, 
Environmental Impacts of Alternatives

8-17

• carbon dioxide—6,068,000 tons (5,995,000 MT) per year, 

• carbon monoxide—847 tons (768 MT) per year, 

• total suspended particles (TSP)—373 tons (338 MT) per year, and

• particulate matter ≤10 μm or PM10—373 tons (338 MT) per year. 

8.2.1.1 Sulfur Oxide and Nitrogen Oxide

A new NGCC plant would have to comply with Title IV of the CAA (42 USC 7651) reduction 

requirements for sulfur oxides and nitrogen oxides, which are the main precursors of acid rain 

and the major cause of reduced visibility. Title IV establishes maximum sulfur oxide and 

nitrogen oxide emission rates from existing plants and a system of sulfur oxide emission 

allowances that can be used, sold, or saved for future use by new plants. In addition, in 

August 2011, EPA published the Cross-State Air Pollution Rule, which included reductions of 

sulfur oxides and nitrogen oxides in Texas. According to the rule, NGCC plants would need to 

comply with the new reductions by 2012.

As stated above, the new NGCC alternative would produce 192 tons (174 MT) per year of sulfur 

oxides and 839 tons (761 MT) per year of nitrogen oxides based on the use of the dry 

low-nitrogen oxide combustion technology and use of the selective catalytic reduction (SCR) to 

significantly reduce nitrogen oxide emissions. The new plant would be subjected to the 

continuous monitoring requirements for sulfur oxides and nitrogen oxides, as specified in 

40 CFR Part 75. The current State Implementation Plan (SIP) for Texas includes a cap and 

trade program for sulfur and nitrogen oxides. To operate the NGCC plant, sulfur dioxide 

allowance would need to be purchased from the open market or an existing fossil-fired plant 

would need to be shut down and those credits would need to be applied to the new plants 

(STPNOC 2010a). Thus, provided the plant operator is able to purchase sufficient allowances 

to operate, the NGCC alternative would not add to the net regional sulfur or nitrogen oxide

emissions, although it might do so locally.

8.2.1.2 Greenhouse Gases

The new plant would release greenhouse gases, such as carbon dioxide and methane. The 

plant would be subjected to the continuous monitoring requirements for carbon dioxide, as 

specified in 40 CFR Part 75. The NGCC plant would emit approximately 6.1 million tons 

(approximately 6.0 million MT) per year of carbon dioxide emissions.

On July 12, 2012, EPA issued a final rule tailoring the applicability criteria that determine which 

stationary sources and modification to existing projects become subject to permitting 

requirements for greenhouse emissions under the PSD and Title V Programs of the CAA 

(77 FR 41051). According to the Tailoring Rule, greenhouse gases are a regulated new source 

review pollutant under the PSD major source permitting program if the source is otherwise 

subject to PSD (for another regulated new source review pollutant) and has a greenhouse gas 

potential to emit equal to or greater than 75,000 tons (68,000 MT) per year of carbon dioxide 

equivalent (“carbon dioxide equivalent” adjusting for different global warming potentials for 

different greenhouse gases). Such sources would be subject to best available control 

technology (BACT), although EPA has yet to determine BACT for greenhouse gases.

EPA issued a Federal Implementation Plan (FIP) on May 3, 2011, to permit greenhouse 

gas-emitting sources in states that do not have measures to lower greenhouse gases in their 

SIP. Because Texas has not updated its SIP to include greenhouse gases, EPA will be the 

official permitting authority for greenhouse gas-emitting sources in Texas if the SIP is not 

updated before the NGCC plant begins operations.
Environmental Impacts of Alternatives

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8.2.1.3 Particulates

The new NGCC alternative would produce 373 tons (338 MT) per year of TSP, all of which 

would be emitted as PM10. STPNOC (2010a) indicated that all PM10 emissions would be 

particulate matter, ≤2.5 μm or PM2.5. DOE (2007) evaluated the emissions from a hypothetical 

560 MWe NGCC unit using BACT to meet the emission requirements of the 2006 New Source 

Performance Standards. DOE concluded that emissions from particulates would be negligible 

because NGCC uses natural gas as fuel; therefore, NGCC plants would not require emissions 

controls equipment or features to reduce these emissions.

During the construction of an NGCC plant, onsite activities would also generate fugitive dust. 

Vehicles and motorized equipment would create exhaust emissions during the construction 

process. These impacts would be intermittent and short-lived; however, to minimize dust 

generation, construction crews would use applicable dust-control measures, as described 

above.

8.2.1.4 Hazardous Air Pollutants

In December 2000, EPA issued regulatory findings (65 FR 79825) on emissions of hazardous

air pollutants (HAPs) from electric utility steam-generating units, which said that natural 

gas-fired plants emit HAPs such as arsenic, formaldehyde, and nickel and stated the following: 

Also in the utility RTC (Report to Congress), the EPA indicated that the impacts 

due to HAP emissions from natural gas-fired electric utility steam generating 

units were negligible based on the results of the study. The Administrator finds 

that regulation of HAP emissions from natural gas-fired electric utility steam 

generating units is not appropriate or necessary.

As a result of EPA’s conclusion, the NRC staff finds no significant air quality effects from HAPs. 

8.2.1.5 Conclusion

Based on this information, the overall air quality impacts of a new NGCC plant located at the 

STP site would be SMALL to MODERATE. Impacts would not be noticeable for sulfur and 

nitrogen oxides because the Texas SIP requires a Cap and Trade Program, and there would be 

no net increase in sulfur and nitrogen oxide emissions. Based on analyses from DOE (2007) 

and EPA (2000, 65 FR 79825), TSPs and HAPs would have negligible impacts. Greenhouse 

gas emissions would be noticeable; carbon dioxide emissions would be two orders of magnitude 

larger than the threshold in EPA’s tailoring rule for greenhouse gas (75,000 tons or 68,000 MT) 

per year of carbon dioxide equivalent), which would trigger a regulated new source review.

8.2.2 Surface Water Resources

STPNOC did not propose using any surface water during the construction of Units 3 and 4 

(NRC 2011). As a new NGCC plant would occupy a much smaller footprint relative to new 

nuclear units, and its construction would entail less extensive excavation and earthwork, NRC 

expects that surface water would not be used during construction for the NGCC alternative.

Some temporary impacts to surface water quality may result from dredging activities in the 

Colorado River near the barge slip and from increased sediment loading in stormwater runoff 

from active construction areas. Due to the short-term nature of the dredging activities, the 

hydrologic alterations and sedimentation would be localized and temporary. Dredging would 

also be conducted under a permit from the USACE requiring the implementation of BMPs to 

minimize impacts. Runoff from construction areas would be controlled under a State-issued 

TPDES general permit that would require implementation of a stormwater pollution prevention 
Environmental Impacts of Alternatives

8-19

plan and associated BMPs to prevent or significantly mitigate soil erosion and contamination of 

stormwater runoff from construction activities.

For facility operations, the NGCC alternative would require much less cooling water than STP, 

Units 1 and 2, and consumptive water use would be much less. It is expected that use of the 

existing intake and discharge infrastructure on the MCR and the Colorado River would be 

sufficient to support this alternative. Surface water withdrawals would be subject to, and would 

remain well within, STPNOC’s existing water rights, and effluent discharges and stormwater 

discharges associated with industrial activity would subject to a revised State-issued TPDES 

permit under this alternative. 

In consideration of the above, the impacts on surface water use and quality from construction 

and operations under the NGCC alternative would be SMALL.

8.2.3 Groundwater Resources

Construction-related ground disturbance and excavation work would be substantially less than 

that described for the new nuclear alternative. Although groundwater dewatering of foundation 

excavations for a new NGCC plant would likely be required, slurry walls and wells were 

proposed for use to minimize potential adverse effects from dewatering both on site and off site 

(NRC 2011). Application of BMPs in accordance with a state-issued NPDES general permit, 

including appropriate waste management and spill prevention practices, would prevent or 

minimize any groundwater quality impacts during construction.

STPNOC assumed that a fossil-fuel-fired generation facility would be located adjacent to the 

STP, Units 1 and 2, site to use the existing infrastructure, including continued use of existing 

onsite groundwater production wells at STP. Groundwater use for construction of a new NGCC 

plant would be substantially less than the volume required for new nuclear units under this 

alternative by virtue of the smaller footprint involved for excavation, earthwork, and structural 

work. This would encompass such uses as potable and sanitary uses, concrete production, 

dust suppression and soil compaction, and other uses.

For NGCC plant operations, NRC assumed that the NGCC alternative would entail the same 

relative ratio of groundwater use to surface water use as that used at STP, Units 1 and 2. This 

includes the use of groundwater for freshwater and service water makeup, potable and sanitary 

uses, and fire protection. Consequently, it is expected that total groundwater usage and 

associated aquifer effects would likely be much less under this alternative than those under 

current STP operations. This is because of the fewer number of auxiliary systems requiring 

groundwater and the much smaller workforce under the NGCC alternative.

Based on this information, the overall impact on groundwater use and quality from construction 

and operations under the NGCC alternative would be SMALL.

8.2.4 Aquatic Ecology

Construction activities for the NGCC alternative (such as construction of heavy haul roads and 

the power blocks) could affect drainage areas or other onsite aquatic features. NRC assumed 

that the plant operator would install temporary and permanent erosion and sediment control 

measures to minimize the flow of disturbed soils into ditches and wetlands. Such BMPs would 

likely be described in a TPDES general permit relating to stormwater discharges for construction 

activities. To bring new materials to the site, NRC assumed the plant operator would dredge 

near the barge slip to transport some materials using barges. Permits and certifications from 

the USACE and other agencies would require the implementation of BMPs to minimize impacts. 
Environmental Impacts of Alternatives

8-20

Due to the short-term nature of the dredging activities, the hydrological alterations to aquatic 

habitats would be localized and temporary.

During operations, the NGCC alternative would require less cooling water to be withdrawn from 

the Colorado River than STP, Units 1 and 2, requires. Therefore, the number of fish and other 

aquatic organisms affected by impingement and entrainment would be less for an NGCC 

alternative than for those associated with license renewal. The NGCC alternative would also 

discharge less thermal effluent because less cooling water would be required. STPNOC’s 

TPDES permit limits the daily discharge to 144 million gpd and shall not exceed 12.5 percent of 

the flow of the Colorado River at the discharge point (TCEQ 2005). STPNOC has discharged to 

the Colorado River once during the operation of STP in 1997 as part of a system test 

(STPNOC 2010a). Because the thermal discharge would be smaller than STP, Units 1 and 2, 

the number of fish and other aquatic organisms affected by heat shock would be less for an 

NGCC alternative than for those associated with license renewal. 

The NGCC plant emission has specific impacts to the aquatic ecology. The cooling system for 

a new NGCC plant would have similar chemical discharges as STP, but the air emissions from 

the NGCC plant would emit particulates that would settle onto the river surface and introduce a 

new source of pollutants that would not exist if STP continued operating. However, the flow of 

the Colorado River would dissipate pollutants, which would decrease the concentration of 

pollutants and minimize the exposure of fish and other aquatic organisms to pollutants.

Construction activities would require BMPs; dredging would be short-term; the surface water 

withdrawal and discharge for this alternative would be less than for STP, Units 1 and 2; and 

pollutants would dissipate within the Colorado River (minimizing exposure concentrations to 

aquatic resources). Therefore, impacts on aquatic ecology would be SMALL.

8.2.5 Terrestrial Ecology

Constructing the NGCC alternative would require approximately 312 ac (126 ha), which includes 

a new pipeline that would run approximately 2 mi (3 km) from the STP site to an existing 

pipeline. These land disturbances form the basis for impacts on terrestrial ecology.

If the NGCC alternative was constructed at the STP site, construction would likely affect a 

variety of habitats and land uses, including industrial land (buildings, parking areas, and 

mowed-maintained fields), drainage ditches, scattered small palustrine wetlands, scrub-shrub 

habitat, and mixed grassland habitat where abandoned farm lands previously existed prior to 

construction of Units 1 and 2. Most of these areas have been mildly to extensively disturbed 

during the construction and operation of Units 1 and 2 and other human activities. After the 

completion of the new units, the plant operator would likely grade, landscape, and replant the 

areas used for temporary building support, which is similar to what STPNOC proposed to do 

after completion of proposed new nuclear Units 3 and 4 (STPNOC 2010b). The majority of 

permanently affected areas would be maintained (e.g., mowed) and industrial areas. The plant 

operator would likely implement BMPs to minimize impacts to wetlands, and the plant operator 

would be required to comply with the USACE 404 permits. Construction activities could also 

adversely affect onsite wildlife through noise, increased light pollution, and increased traffic. 

However, these impacts would be temporary and minor.

Gas extraction and collection would also affect terrestrial ecology in offsite gas fields, although 

much of this land is likely already disturbed by gas extraction, and the incremental effects of this 

alternative on gas field terrestrial ecology are difficult to gauge.

Construction of the 2-mi (3-km) natural gas pipeline could also increase habitat fragmentation. 

To the extent possible, STPNOC would route the pipeline through previously disturbed areas 
Environmental Impacts of Alternatives

8-21

(STPNOC 2010a). Threatened and endangered species may also be affected by construction 

of the natural gas pipeline. Long-linear projects, such as pipelines, can often be sited to avoid 

sensitive areas. Once construction is completed, impacts would be minimal, especially in 

previously disturbed areas.

Because many construction-related impacts would be temporary, and because the majority of 

long-term construction impacts would occur within previously disturbed areas, impacts on 

terrestrial resources would be SMALL.

8.2.6 Human Health

An NGCC plant would emit criteria air pollutants, but generally in smaller quantities than a 

coal-fired plant (except nitrogen oxide, which requires additional controls to reduce emissions). 

The human health effects of NGCC generation are generally low, although in Table 8–2 of the 

GEIS (NRC 1996), the NRC identified cancer and emphysema as potential health risks from 

natural gas-fired plants. Nitrogen oxide emissions contribute to ozone formation, which in turn 

contributes to human health risks. Emission controls on this NGCC alternative maintain 

nitrogen oxide emissions well below air quality standards established for the purposes of 

protecting human health, and emissions trading or offset requirements mean that overall 

nitrogen oxide in the region would not increase. Health risks to workers may also result from 

handling spent catalysts that may contain heavy metals.

Overall, human health risks to occupational workers and to members of the public from NGCC 

plant emissions sited at the STP site would likely be SMALL.

Noise during plant operations would be limited to industrial processes and communications. 

Pipelines delivering natural gas fuel could be audible off site near compressor stations. Pipeline 

companies would need to adhere to local ordinances regarding maximum noise levels during 

construction and at compressor stations. Therefore, impacts from noise would likely be SMALL.

8.2.7 Land Use 

The GEIS generically evaluates the impact of constructing and operating various replacement 

power plant alternatives on land use, both on and off each plant site. The analysis of land use 

impacts focuses on the amount of land area that would be affected by the construction and 

operation of a four-unit NGCC plant at the STP site.

Based on scaled GEIS estimates and information provided by STPNOC in its ER, approximately 

312 ac (126 ha) of land would be needed to support an NGCC alternative to replace STP. This 

amount of land use would include other plant structures and associated infrastructure, such as 

the new 2-mi (3-km) pipeline, and is unlikely to exceed 312 ac (126 ha), excluding land for 

natural gas wells and collection stations.

In addition to onsite land requirements, land would be required off site for natural gas wells and 

collection stations. Scaling from GEIS estimates, approximately 9,600 ac (3,885 ha) would be 

required for wells and collection stations to bring the gas to the plant. Gas well and collection 

stations could noticeably alter land use in those areas, although most of this land requirement 

would occur in areas where gas extraction already occurs.

The elimination of uranium fuel for STP could partially offset offsite land requirements. Scaling 

from GEIS estimates approximately 2,560 ac (1,036 ha) would not be needed for mining and 

processing uranium during the operating life of the plant. Overall land-use impacts from the

natural gas alternative (considering the amount of additional offsite land needed for NGCC gas 
Environmental Impacts of Alternatives

8-22

pipeline infrastructure and gas well and collection station development) could range from

SMALL to MODERATE.

8.2.8 Socioeconomics

Socioeconomic impacts are defined in terms of changes to the demographic and economic 

characteristics and social conditions of a region. For example, the number of jobs created by 

the construction and operation of a power plant could affect regional employment, income, and 

expenditures. Two types of jobs would be created by this alternative: (1) construction-related 

jobs, which are transient, short in duration, and less likely to have a long-term socioeconomic 

impact; and (2) power plant operation jobs, which have the greater potential for permanent, 

long-term socioeconomic impacts. Workforce requirements for the construction and operation 

of the NGCC alternative were evaluated to measure their possible effects on current 

socioeconomic conditions.

Scaling from GEIS estimates, the construction workforce would peak at 3,200 workers. 

STPNOC projected a maximum construction workforce of 2,028 workers (STPNOC 2010a). 

STPNOC’s estimate appears reasonable; therefore, it is used in this analysis. The relative 

economic impact of this many workers on the local economy and tax base would vary, with the 

greatest impacts occurring in the communities where the majority of construction workers would 

reside and spend their income. As a result, local communities could experience a short-term 

economic “boom” from increased tax revenue and income generated by construction 

expenditures and the increased demand for temporary (rental) housing and business services. 

Some construction workers could relocate to Matagorda and surrounding counties in order to be 

closer to the construction work site. However, given the proximity of STP to the Houston 

metropolitan area, many construction workers could commute to the STP site, thereby lessening 

the need for additional rental housing near STP. 

After completing the installation of the four-unit NGCC plant, local communities could 

experience a return to pre-construction economic conditions. Based on this information, and 

given the number of workers, socioeconomic impacts during construction in communities near 

the STP site could range from SMALL to MODERATE.

Scaling from GEIS estimates, the plant operation workforce would be 400 workers. STPNOC 

estimated a plant operations workforce of approximately 97 workers. The STPNOC estimate 

appears to be reasonable and is consistent with trends toward lowering labor costs by reducing 

the size of plant operations workforces. The amount of property taxes paid under the NGCC 

alternative may increase if additional land is required off site to support this alternative. 

Socioeconomic impacts during operations could range from SMALL to MODERATE as the STP 

site transitions to the new NGCC power plant. The potential reduction in overall employment at 

STP could affect property tax revenue and income in local communities and businesses. In 

addition, the permanent housing market could also experience increased vacancies and 

decreased prices if operations workers and their families move out of the region.

8.2.9 Transportation

Transportation impacts associated with construction and operation of a four-unit, NGCC plant 

would consist of commuting workers and truck deliveries of construction materials to the STP 

site. During periods of peak construction activity, up to 2,028 workers could be commuting daily 

to the site (STPNOC 2010a). Workers commuting to the STP site would primarily use two-lane 

roads. The volume of traffic on these roads, and especially FM 521, would increase 

substantially. In addition to commuting workers, trucks would be transporting construction 

materials and equipment to the worksite, thus increasing the amount of traffic on local roads. 
Environmental Impacts of Alternatives

8-23

The increase in vehicular traffic would peak during shift changes, resulting in temporary levels of 

service impacts and delays at intersections. Pipeline construction and modification to existing 

natural gas pipeline systems could also have a temporary impact. Some power plant 

components and materials could also be delivered by train or barge. Train deliveries could 

cause additional traffic delays at railroad crossings. Based on this information, traffic-related 

transportation impacts during construction could range from SMALL to MODERATE.

Traffic-related transportation impacts would be greatly reduced after completing the installation 

of the new NGCC units. Transportation impacts would include daily commuting by the operating 

workforce, equipment and materials deliveries, and the removal of commercial waste material to 

offsite disposal or recycling facilities by truck. During operations, the estimated number of 

operations workers commuting to and from STP would be 97 workers (STPNOC 2010a). Since 

fuel is transported by pipeline, the transportation infrastructure would experience little to no 

increased traffic from plant operations. Traffic-related transportation impacts would be 

considerably less than current operations because the new NGCC power plant would employ 

far fewer workers than STP, Units 1 and 2. Overall, transportation impacts would be SMALL 

during plant operations.

8.2.10 Aesthetics

The analysis of aesthetic impacts focuses on the degree of contrast between the NGCC 

alternative and the surrounding landscape and the visibility of the NGCC plant. During 

construction, all of the clearing and excavation would occur on the STP site. These activities 

may be visible from offsite roads, particularly FM 521. Since the STP site already appears 

industrial, construction of the NGCC power plant would appear similar to onsite activities during 

refueling outages.

The four NGCC units could be approximately 100 ft (30 m) tall, with two exhaust stacks up to 

175 ft (53 m) tall. The facility would be visible off site during daylight hours, and some 

structures may require aircraft warning lights. The power plant would be smaller and less 

noticeable than STP, Units 1 and 2, which has a reactor building height of approximately 250 ft 

(76 m) (STPNOC 2010b). Noise generated during NGCC power plant operations would be 

limited to routine industrial processes and communications. Pipelines delivering natural gas fuel 

could be audible off site near gas compressor stations.

In general, given the industrial appearance of the STP site, the new NGCC power plant would 

blend in with the surroundings if the existing STP, Units 1 and 2, remains. Aesthetic changes 

would be limited to the immediate vicinity of the existing STP site, and any impacts would be 

SMALL. 

8.2.11 Historic and Archaeological Resources

The same considerations, discussed in Section 8.1.11, for the impact of the construction of a 

new nuclear plant on historic and archaeological resources apply to the construction activities 

that would occur on the STP site for an NGCC plant. As described in Section 2.2.10, much of 

the STP site has been previously disturbed by the construction of STP, Units 1 and 2. In 

addition, in preparation for the COL application for Units 3 and 4, STPNOC conducted a cultural 

resources assessment of the STP site. STPNOC reviewed existing information for the STP site 

and the area within a 10-mi (16-km) radius. STPNOC concluded that any cultural resource sites 

that may have existed on site would no longer retain their integrity because the area was heavily 

disturbed during the construction of Units 1 and 2 (STPNOC 2010b). In December 2006, 

STPNOC reported these findings to the SHPO at the Texas Historical Commission. The SHPO 
Environmental Impacts of Alternatives

8-24

concurred, in January 2007, that there would be no impacts to historic properties

(STPNOC 2006; THC 2007).

There is a low potential for cultural resources to be located in previously undisturbed portions of 

the STP site. However, if the NGCC units were to be sited within undisturbed areas or within 

areas of known cultural sensitivity (historic grave site located on the property and described in 

Section 2.2.10), these areas would need to be surveyed by a professional archaeologist to 

identify and develop possible mitigation measures to address any adverse effects from project 

activities. NRC assumes the plant operator would follow similar procedures to those described 

in the final EIS for STP, Units 3 and 4 (NRC 2011), if the plant operator discovered any historic 

or cultural resources during ground-disturbing activities associated with building the new units.

Studies would be needed for all areas of potential disturbance at the proposed plant site and 

along associated corridors where new construction would occur (e.g., the new 2-mi pipeline, 

roads, transmission corridors, rail lines, or other rights-of-way (ROWs)). In most cases, 

long-linear projects can be sited to avoid areas of greatest sensitivity.

The NRC staff determined that the impact of the NGCC alternative at the STP site on historic 

and archaeological resources would be SMALL for the following reasons:

• NRC (2011) and STPNOC (2010a, 2010b) did not identify any cultural 

resources that could be affected by Units 3 and 4. 

• The SHPO determined that construction for Units 3 and 4 would not affect 

cultural and historic resources. 

• Long-linear projects (e.g., pipelines) can usually be sited to avoid sensitive 

areas. 

• NRC assumes that the plant operator would follow environmental compliance 

procedures for new ground-disturbing activities.

8.2.12 Environmental Justice

The environmental justice impact analysis evaluates the potential for disproportionately high and 

adverse human health, environmental, and socioeconomic effects on minority and low-income 

populations that could result from the construction and operation of a new power plant. As 

previously discussed in Section 8.1.12, such effects may include human health, biological, 

cultural, economic, or social impacts. Some of these potential effects have been identified in 

resource areas discussed in this SEIS. For example, increased demand for rental housing 

during plant construction could disproportionately affect low-income populations. Minority and 

low-income populations are subsets of the general public living near the STP site, and all are 

exposed to the same hazards generated from constructing and operating a new NGCC plant. 

Section 4.9.7, “Environmental Justice,” presents demographic information about minority and 

low-income populations residing in the vicinity of the STP site. 

Potential impacts to minority and low-income populations from the construction and operation of 

a new NGCC plant at the STP site would mostly consist of environmental and socioeconomic 

effects (e.g., noise, dust, traffic, employment, and housing impacts). Noise and dust impacts 

during construction would be short-term and primarily limited to onsite activities. Minority and 

low-income populations residing along site access roads would be directly affected by increased 

commuter vehicle and truck traffic. However, because of the temporary nature of construction, 

these effects would only occur during certain hours of the day and are unlikely to be high and 

adverse. Increased demand for rental housing during construction could also affect low-income 

populations living near STP. However, given the proximity of STP to the Houston metropolitan 
Environmental Impacts of Alternatives

8-25

area, many construction workers could commute to the STP site, thereby lessening the 

additional need for rental housing.

Based on this information, and the analysis of human health and environmental impacts 

presented in this SEIS, the construction and operation of a new NGCC power plant would not 

have disproportionately high and adverse human health and environmental effects on minority 

and low-income populations residing in the vicinity of the STP site. 

8.2.13 Waste Management

During the construction stage of the NGCC generation alternative, land clearing and other 

construction activities would generate waste that could be recycled, disposed of on site, or 

shipped to an offsite waste disposal facility. Because the alternative would be constructed on or 

near the previously disturbed STP site, the amounts of waste produced during land clearing 

would be reduced.

During the operational stage, spent SCR catalysts, which are used to control nitrogen oxide 

emissions from the NGCC plants, would make up the majority of the waste generated by this 

alternative.

According to the GEIS (NRC 1996), an NGCC plant would generate minimal waste. Waste 

impacts would therefore be SMALL for an NGCC alternative located at the STP site.

8.2.14 Summary of Impacts for the NGCC Generation Alternative

Table 8–3 summarizes the environmental impacts of the NGCC alternative compared to 

continued operation of STP.

Table 8–3. Summary of Environmental Impacts of the NGCC Alternative

Compared to Continued Operation of STP

Category

Natural Gas Combined-Cycle 

Generation Continued STP Operation

Air quality SMALL to MODERATE SMALL

Surface water SMALL SMALL

Groundwater SMALL SMALL

Aquatic resources SMALL SMALL

Terrestrial resources SMALL SMALL

Human health SMALL SMALL to MODERATE

Land use SMALL to MODERATE SMALL

Socioeconomics SMALL to MODERATE SMALL

Transportation SMALL to MODERATE SMALL

Aesthetics SMALL SMALL

Historic & archaeological SMALL SMALL

Waste management SMALL SMALL
Environmental Impacts of Alternatives

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8.3 Supercritical Coal-Fired Generation

In this section, the NRC staff evaluates the environmental impacts of supercritical coal-fired 

generation at the STP site.

Coal-fired generation accounted for 40 percent of all electricity generated in the ERCOT service 

area in 2010, accounting for the greatest share of electrical power (ERCOT 2011a). 

Furthermore, the EIA projects that coal-fired power plants will account for the greatest share of 

capacity additions through 2035—more than natural gas, nuclear, or renewable generation 

options (EIA 2011a). Development of new coal-fired plants may be affected by perceived or 

actual action to limit greenhouse gas emissions. TCEQ has recently granted permits to several 

recently proposed coal-fired plants (TCEQ 2011). Supercritical coal-fired plants are feasible, 

commercially available options for providing electrical generating capacity beyond STPNOC’s 

current license expiration. Therefore, NRC considered supercritical coal fired-generation a 

reasonable alternative to STP license renewal.

Supercritical technologies are increasingly common in new coal-fired plants. Supercritical 

facilities operate at higher temperatures and pressures than most existing coal-fired plants. At 

the critical point, there is no change of state when pressure is increased or if heat is added. For 

states above the critical point, the steam is supercritical. Operating at higher temperatures and 

pressures allows the supercritical coal-fired alternative to operate at a higher thermal efficiency 

than subcritical coal-fired power plants. While supercritical facilities are more expensive to 

construct, they consume less fuel for a given output, reducing environmental impacts. Based on 

technology forecasts from EIA, the NRC staff expects that a new, supercritical coal-fired plant 

would operate at a heat rate of 8,740 Btu/kWh (EIA 2011b).

In a supercritical coal-fired power plant, burning coal heats pressurized water. As the 

supercritical steam and water mixture moves through plant pipes to a turbine generator, the 

pressure drops. The mixture flashes to steam. The heated steam expands across the turbine 

stages, which then spin and turn the generator to produce electricity. After passing through the 

turbine, any remaining steam is condensed back to water in the plant’s condenser.

To replace the 2,500 MWe of power that STP generates, the NRC staff considered four 

hypothetical coal-fired units, each with a net capacity of 640 MWe. The hypothetical coal-fired 

plant would require a similar amount of water as STP, Units 1 and 2. Therefore, the NRC staff 

assumed that the existing cooling water system, including the intakes and discharges on the 

MCR and the Colorado River, would be sufficient for this alternative. The coal-fired alternative 

at the STP site would also use the existing STP transmission system.

The hypothetical 2,560 MWe power plant would consume 11.4 million tons (10.4 MT) of coal 

annually, based on an average heat content of 8,200 British thermal units per pound (Btu/lb)

(STPNOC 2010a). EPA (2011a) reported that the majority of coal plants within the ERCOT 

region use subbituminous coal. The other coal plants used lignite or combined subbituminous 

coal with lignite. While lignite is the most common type of coal found in Texas, NRC assumed 

that the hypothetical coal plant for this alternative would use subbituminous coal because when 

combusted, it releases lower levels of Federal CAA criteria pollutants, such as carbon dioxide, 

nitrous oxides, sulfuric oxides, and particulate matter (TCPA 2008).

Texas coal plants commonly use Power River Basin coal (STPNOC 2010a; TCPA 2008). Given 

current coal mining operations in Wyoming, the coal used in this alternative would likely be 

mined in surface mines, then mechanically processed and washed, before being transported—

likely by rail—to the power plant site. Limestone for scrubbers would also likely arrive by rail 

(STPNOC 2010a). This coal-fired alternative would produce roughly 446,000 tons 

(405,000 MT) of ash, and 43 percent (193,000 tons (175,000 MT)) of the ash would be recycled 
Environmental Impacts of Alternatives

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for beneficial use (STPNOC 2010a). STPNOC (2010a) estimated that approximately 

88,000 tons (80,000 MT) of scrubber sludge would be disposed of on site each year, which was 

based on an assumed annual lime usage of approximately 107,000 tons (97 MT). 

Approximately 200 ac (81 ha) would be required to dispose of the ash and scrubber waste on

site over a 40-year plant life (STPNOC 2010a).

Construction of onsite visible structures would include the boilers and heat-recovery steam 

generators (which may be enclosed in a single building), exhaust stacks, and an electrical 

switchyard. Based on GEIS estimates, the plant would require approximately 4,629 ac 

(1,873 ha) of land. STPNOC (2010a) estimates that 353 ac (143 ha) of land would be required. 

This estimate appears reasonable; therefore, it is used for this analysis.

To build the coal-fired alternative, site crews would clear the plant site of vegetation, prepare the 

site surface, and begin excavation before other crews begin actual construction on the plant and 

any associated infrastructure. Construction materials would be delivered via rail spur, truck, or 

barge. For the proposed construction of Units 3 and 4, STPNOC proposed dredging near the 

current barge slip and upgrading the existing rail spur to accommodate shipments of 

construction materials (STPNOC 2010b). The NRC staff finds this to be reasonable and 

assumed that dredging and rail spur upgrades would be required for the coal-fired alternative.

The NRC also considered an integrated gasification combined cycle (IGCC) coal-fired plant. 

IGCC is an emerging technology for generating electricity with coal that combines modern coal 

gasification technology with both gas turbine and steam turbine power generation. The 

technology is cleaner than conventional pulverized coal plants because major pollutants can be 

removed from the gas stream before combustion. The IGCC alternative also generates less 

solid waste than the pulverized coal-fired alternative. The largest solid waste stream produced 

by IGCC installations is slag, a black, glassy, sand-like material that is potentially a marketable 

byproduct. The other large-volume byproduct produced by IGCC plants is sulfur, which is 

extracted during the gasification process and can be marketed rather than placed in a landfill. 

IGCC units do not produce ash or scrubber wastes. In spite of the preceding advantages, the 

NRC concluded in the final EIS for the proposed Units 3 and 4 (NRC 2011) that a new IGCC 

plant is not a reasonable alternative for the following reasons: 

• IGCC plants are more expensive than comparable pulverized coal plants 

(NETL 2007). 

• The few existing IGCC plants in the U.S. have considerably smaller capacity

(approximately 250 MWe each) than STP, Units 1 and 2. 

• System reliability of existing IGCC plants has been lower than pulverized coal 

plants. 

• The existing IGCC plants have had an extended (though ultimately 

successful) operational testing period (NPCC 2005). 

• A lack of overall plant performance warranties for IGCC plants has hindered 

commercial financing (NPCC 2005). 

At present, the NRC continues to finds this determination reasonable. While the capacity of 

some of the proposed IGCC plants has grown slightly, most proposed IGCC plants are still 

considerable smaller than STP, Units 1 and 2. For example, on September 27, 2011, DOE 

approved a loan to Summit Texas Clean Energy, LLC, for a 400 MWe IGCC plant to be built 

west of Midland-Odessa, Texas (DOE 2011a). Although NRC considered an IGCC plant as an 

alternative for the Shearon Harris license renewal SEIS, whose license would also have expired 

in 2027, the Shearon Harris nuclear plant is much smaller than STP, Units 1 and 2 (955 MWe
Environmental Impacts of Alternatives

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as compared to 2,500 MWe) (NRC 2008). Because of the small capacity of proposed IGCC 

plants, the NRC did not find IGCC to be a reasonable alternative for STP, Units 1 and 2. For 

these reasons, IGCC plants are not considered further in this SEIS. 

8.3.1 Air Quality

Air quality impacts from coal-fired generation can be substantial because it emits a significant 

quantity of sulfur oxides, nitrogen oxides, particulates, carbon monoxide, and HAPs such as 

mercury; however, many of these pollutants can be effectively controlled by various 

technologies.

As discussed in Section 2.2.2.1, STP is located in central Matagorda County, Texas, at the 

southern edge of the Metropolitan Houston–Galveston Intrastate Air Quality Control Region 

(40 CFR 81.38). The Corpus Christi–Victoria Intrastate Air Quality Control Region 

(40 CFR 81.136) lies immediately south and west of Matagorda County. EPA has designated 

all of the counties in these Air Quality Control Regions adjacent to the STP site as in compliance 

with the National Ambient Air Quality Standards (40 CFR 81.344) except Brazoria County to the 

north; Brazoria County is classified Nonattainment/Severe relative to the 8-hour ozone standard 

(EPA 2011b). 

Construction activities would cause some localized temporary air-quality effects because of 

emissions and fugitive dust from operation of the earth-moving and material-handling 

equipment. Emissions from workers’ vehicles and motorized construction equipment exhaust 

would be temporary. NRC assumed that construction crews would use dust-control practices to 

control and reduce fugitive dust. STPNOC proposed such activities during construction of 

proposed Units 3 and 4 (STPNOC 2010b), and §111.145 of TCEQ’s regulations require dust 

suppression control during the construction of facilities and parking lots.

A new coal-fired plant would qualify as a new major-emitting industrial facility and would be 

subject to PSD requirements of the CAA (EPA 2011c). The coal-fired plant would need to 

comply with the standards of performance for electric utility steam generating units set forth in 

40 CFR Part 60 Subpart Da and GG. The plant would also require an operating permit from 

TCEQ. In STPNOC’s ER for Units 3 and 4, STPNOC stated that “[a]ir emissions sources would 

be managed in accordance with Federal, Texas, and local air quality control laws and 

regulations.” Likewise, NRC assumed that the coal-fired plant would be operated in accordance 

with Federal, Texas, and local air quality control laws and regulations.

Subpart P of 40 CFR Part 51 contains the visibility protection regulatory requirements, including 

the review of new sources that would be constructed in the attainment or unclassified areas and 

may affect visibility in any Federal Class I area. If a coal-fired alternative was located close to a 

mandatory Class I area, additional air pollution control requirements would be required. As 

noted in Section 2.2.2.1, there are no mandatory Class I Federal areas within 50 mi (80 km) of 

the STP site.

The emissions from the coal-fired alternative at the STP site, projected by the NRC staff based 

on published EIA data, EPA emission factors, and based on performance characteristics for this 

alternative and likely emission controls, would be:

• sulfur oxides—3,260 tons (2,958 MT) per year, 

• nitrogen oxides—2,869 tons (2,595 MT) per year, 

• carbon monoxide—784 tons (711 MT) per year, 
Environmental Impacts of Alternatives

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• particulate matter PM10—446 tons (405 MT) per year, and

• particulate matter PM2.5—223 tons (202 MT) per year. 

8.3.1.1 Sulfur Oxides

The coal-fired alternative at the STP site would likely use wet, limestone-based scrubbers to 

remove sulfur oxides. EPA indicates that this technology can remove more than 95 percent of 

sulfur oxides from flue gases. The staff projects total sulfur oxide emissions would be 

3,260 tons (2,958 MT) per year. Sulfur oxide emissions from a new coal-fired power plant 

would be subject to the requirements of the CAA (42 U.S.C. §7651 et seq.). These regulations 

were enacted to reduce emissions of sulfur dioxide and nitrogen oxide, the two principal 

precursors of acid rain, by restricting emissions of these pollutants from power plants. The 

current SIP for Texas includes a Cap and Trade Program for sulfur dioxide. To operate the 

coal-fired plant, the plant operator would have to purchase sulfur dioxide allowances from the 

open market or shut down existing fossil-fired plant(s) and apply the credits to the new plant 

(STPNOC 2010a). Thus, provided the plant operator is able to purchase sufficient allowances 

to operate, the coal-fired alternative would not add to net regional sulfur dioxide emissions, 

although it might do so locally.

In addition, in August 2011, EPA published the Cross-State Air Pollution Rule, which included 

reductions of sulfur dioxide in Texas. According to the rule, coal-fired plants would need to 

comply with the new reductions by 2012.

8.3.1.2 Nitrogen Oxides 

A coal-fired alternative at the STP site would most likely employ various available nitrogen 

oxide-control technologies, which can be grouped into two main categories—combustion 

modifications and post-combustion processes. Combustion modifications include low-nitrogen 

oxide burners, overfire air, reburning, flue gas recirculation, and operational modifications. 

Post-combustion processes include SCR, selective noncatalytic reduction, and hybrid 

processes. Effective combination of the combustion modifications and post-combustion 

processes reduces nitrogen oxide emissions by up to 95 percent (EPA 1998). STPNOC 

indicated in its ER that it would use low-nitrogen oxide burners, overfire air, selective catalytic 

reduction, and scrubbers to reduce nitrogen oxide emissions from this alternative 

(STPNOC 2010a). Assuming the use of such technologies at the STP site, nitrogen oxide 

emissions after scrubbing would be approximately 2,869 tons (2,595 MT) annually.

Section 407 of the CAA establishes technology-based emission limitations for nitrogen oxide 

emissions. A new coal-fired power plant would be subject to the new source performance 

standards for such plants as indicated in 40 CFR 60.44 Subpart Da(a)(1). This regulation limits 

the discharge of any gases that contain nitrogen oxides to 200 nanograms (ng) of nitrogen 

oxides per joule (J) of gross energy output (equivalent to 1.6 pounds per megawatt-hours 

(lb/MWh), based on a 30-day rolling average.

The current SIP for Texas includes a Cap and Trade Program for nitrogen oxides. To operate 

the coal-fired plant, the plant operator would have to purchase nitrogen oxide allowances from 

the open market or shut down existing fossil-fired plant(s) and apply the credits to the new plant 

(STPNOC 2010a). Thus, provided the plant operator is able to purchase sufficient allowances 

to operate, the coal-fired alternative would not add to net regional nitrogen oxide emissions, 

although it might do so locally.

8.3.1.3 Greenhouse Gases

A coal-fired plant would also have carbon dioxide emissions during operations, as well as during 

coal mining, processing, and transportation. The coal-fired plant would emit between 
Environmental Impacts of Alternatives

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19.3 million tons (17.5 million MT) and 19.9 million tons (18.1 million MT) of carbon dioxide per 

year from coal combustion, depending on the type and quality of the coal burned.

On July 12, 2012, EPA issued a final rule tailoring the applicability criteria that determine which

stationary sources and modification to existing projects become subject to permitting 

requirements for greenhouse emissions under the PSD and Title V Programs of the CAA

(77 FR 41051). According to the Tailoring Rule, greenhouse gases are a regulated new source 

review pollutant under the PSD major source permitting program if the source is otherwise 

subject to PSD (for another regulated new source review pollutant) and has a greenhouse gas 

potential to emit equal to or greater than 75,000 tons (68,000 MT) per year of carbon dioxide 

equivalent (“carbon dioxide equivalent” adjusting for different global warming potentials for 

different greenhouse gases). Such sources would be subject to BACT, although EPA has yet to 

determine BACT for greenhouse gases.

EPA issued a Federal Implementation Plan (FIP) on May 3, 2011, to permit greenhouse 

gas-emitting sources in states that do not have measures to lower greenhouse gases in their 

SIP. Because Texas has not updated its SIP to include greenhouse gases, EPA will be the 

official permitting authority for greenhouse gas-emitting sources in Texas if the SIP is not 

updated before the coal-fired plant begins operations.

8.3.1.4 Particulates

The new coal-fired power plant would use fabric filters to remove particulates from flue gases 

(STPNOC 2010a). The fabric filters would remove 99.9 percent of PM (STPNOC 2010a). EPA 

notes that filters are capable of removing in excess of 99 percent of PM and that sulfur dioxide 

scrubbers further reduce PM emissions (EPA 2008); therefore, the NRC staff believes the 

STPNOC removal factor is appropriate. Based on this information, the new supercritical 

coal-fired plant would emit approximately 446 tons (405 MT) per year of particulate matter 

having an aerodynamic diameter less than, or equal to, 10 microns (PM10) annually. In addition, 

coal burning would also result in approximately 223 tons (202 MT) of particulate matter with an 

aerodynamic diameter of 2.5 microns or less (PM2.5). Coal-handling equipment would introduce 

fugitive dust emissions when fuel is being transferred to onsite storage and then reclaimed from 

storage for use in the plant.

During the construction of a coal-fired plant, onsite activities would also generate fugitive dust. 

Vehicles and motorized equipment would create exhaust emissions during the construction 

process. These impacts would be intermittent and short-lived; however, to minimize dust 

generation, construction crews would use applicable dust-control measures, as described 

above.

8.3.1.5 Carbon Monoxide

Based upon EPA emission factors (EPA 1998), the NRC staff estimates that total carbon 

monoxide emissions would be approximately 784 tons (711 MT) per year.

8.3.1.6 Conclusion

While the GElS analysis mentions global warming from carbon dioxide emissions and acid rain 

from sulfur and nitrogen oxide emissions as potential impacts, it does not quantify emissions 

from coal-fired power plants; however, the GElS analysis does imply that air impacts would be 

substantial (NRC 1996). The above analysis shows that emissions of air pollutants—including 

sulfur oxides, nitrogen oxides, carbon monoxide, particulates, and carbon dioxide—exceed 

those produced by the existing nuclear power plant, as well as those of the other alternatives 

considered in this section. The NRC analysis for a coal-fired alternative suggests that impacts 

from the coal-fired alternative would have clearly noticeable effects, but given existing regulatory 
Environmental Impacts of Alternatives

8-31

regimens, permit requirements, and emissions controls, the coal-fired alternative would not 

destabilize air quality. Based on this information, the overall air quality impacts of a new 

coal-fired plant located at the STP site would be MODERATE.

8.3.2 Surface Water Resources

STPNOC did not propose using any surface water during the construction of Units 3 and 4 

(NRC 2011). As a new coal-fired plant would occupy a smaller footprint relative to new nuclear 

units, its construction would enable less extensive excavation and earthwork than new nuclear 

units. 

However, onsite construction of an engineered solid waste disposal facility (landfill), totaling 

200 ac (80 ha), would also be required for disposal of coal ash and air pollution control scrubber 

sludge from 20 years of operations. The combined acreage of the coal-fired plant and ash 

disposal facility would slightly exceed that required for the new nuclear generation alternative. 

Nevertheless, NRC would still expect that surface water would not be used to support 

construction activities under this alternative.

As for the aforementioned replacement-power alternatives, some temporary impacts to surface 

water quality may result from dredging activities in the Colorado River near the barge slip and 

from increased sediment loading in stormwater runoff from active construction areas. Due to 

the short-term nature of the dredging activities, the hydrologic alterations and sedimentation 

would be localized and temporary. Dredging would also be conducted under a permit from the 

USACE requiring the implementation of BMPs to minimize impacts. Runoff from construction 

areas, including construction of the disposal facility, would be controlled under a State-issued 

TPDES general permit that would require implementation of a stormwater pollution prevention 

plan and associated BMPs to prevent or significantly mitigate soil erosion and contamination of 

stormwater runoff from construction activities.

During operations, the coal-fired alternative would require a similar amount of cooling water as 

STP, Units 1 and 2. Because a similar amount of cooling water would be required, NRC 

expects that the existing intake and discharges on the MCR and the Colorado River would be 

sufficient to support this alternative. Surface water withdrawals would be subject to, and would 

remain well within, STPNOC’s existing water rights, and effluent discharges and stormwater 

discharges associated with industrial activity would be subject to a revised State-issued TPDES 

permit under this alternative. In accordance with the applicable TPDES permit, implementation 

of a stormwater pollution prevention plan for industrial activities would address stormwater 

run-on and runoff issues associated with coal storage and handling, as well as other stockpiles 

(e.g., lime) at the plant. These requirements would also encompass the handling, storage, and 

disposal of coal ash and scrubber wastes so as to mitigate the potential water quality impacts of 

contaminated runoff and infiltration.

In consideration of the information above, the impacts on surface water use and quality from 

construction and operations under the coal-fired generation alternative would be SMALL.

8.3.3 Groundwater Resources

Construction-related ground disturbance and excavation work would be somewhat less than 

that described for the new nuclear alternative, mainly due to a reduction in deep excavation 

work and less intensive structural work. However, construction and excavation for a coal ash 

and scrubber residue disposal facility would have additional potential impacts on groundwater. 

Although groundwater dewatering of foundation excavations for a new coal-fired plant would 

likely be required, slurry walls and wells were proposed for use to minimize potential adverse 
Environmental Impacts of Alternatives

8-32

effects from dewatering both on site and off site (NRC 2011). Construction of the coal ash and 

scrubber residue disposal facility would have to be carefully managed and sited to minimize the 

need for construction dewatering due to the shallow depth of groundwater across many areas of 

the STP site. Application of BMPs in accordance with a state-issued NPDES general permit, 

including appropriate waste management and spill prevention practices, would prevent or 

minimize groundwater quality impacts during construction.

STPNOC assumed that a fossil-fuel-fired generation facility would be located adjacent to the 

STP, Units 1 and 2, site to use the existing infrastructure, including continued use of the existing 

onsite groundwater production wells at STP. Groundwater use for construction of a new 

coal-fired plant is expected to be similar to the volume required for new nuclear units under this 

alternative. This would encompass such uses as potable and sanitary uses, concrete 

production, dust suppression and soil compaction, and other uses.

For coal-fired plant operations, NRC assumed that the coal-fired generation alternative would 

entail the same relative ratio of groundwater use to surface water use as that used at STP, 

Units 1 and 2. This includes the use of groundwater for freshwater and service water makeup, 

potable and sanitary uses, and fire protection. It is expected that total groundwater usage and 

associated aquifer effects would likely be less than those under current STP operations. This is 

because of the fewer number of auxiliary systems requiring groundwater and the smaller 

workforce under the coal-fired generation alternative.

Disposal of coal ash and air pollution control scrubber wastes in an onsite landfill would have 

the potential to impact groundwater quality due to the generation and infiltration of leachate to 

the environment. NRC assumes that any disposal facility would incorporate a liner to prevent 

infiltration and would be operated with a leachate monitoring and collection system and ambient 

groundwater monitoring system. These systems and measures would ensure that facility 

operations would not impact groundwater quality. Operation of the facility would also be subject 

to a state-issued landfill permit.

Based on this information, the overall impact on groundwater use and quality from construction 

and operations under the coal-fired generation alternative would be SMALL.

8.3.4 Aquatic Ecology

Construction activities for the coal-fired alternative (such as construction of heavy haul roads 

and the power blocks) could affect drainage areas or other onsite aquatic features due to site 

runoff. NRC assumed that the plant operator would install temporary and permanent erosion 

and sediment control measures to minimize the flow of disturbed soils into ditches and 

wetlands. Such BMPs would likely be described in a TPDES general permit relating to

stormwater discharges for construction activities. To bring new materials to the site, NRC 

assumed the plant operator would dredge near the barge slip to transport some materials using 

barges. Permits and certifications from the USACE and other agencies would require the 

implementation of BMPs to minimize impacts. Due to the short-term nature of the dredging 

activities, the hydrological alterations to aquatic habitats would be localized and temporary.

During operations, the coal-fired alternative would require a similar amount of cooling water to 

be withdrawn from the Colorado River at STP, Units 1 and 2, and the thermal discharge would 

also be similar to STP, Units 1 and 2. Therefore, the number of fish and other aquatic 

organisms affected by impingement, entrainment, and heat shock would be similar for a 

coal-fired alternative as for license renewal. The cooling system for a new coal-fired plant would 

have similar chemical discharges as STP, but the air emissions from the coal-fired plant would 

emit particulates that would settle onto the river surface and introduce a new source of 

pollutants that would not exist if STP continued operating. However, the flow of the Colorado 
Environmental Impacts of Alternatives

8-33

River would dissipate pollutants, which would decrease the concentration of pollutants and 

minimize the exposure of fish and other aquatic organisms to pollutants.

Construction activities would require BMPs; dredging would be short-term; the surface water 

withdrawal and discharge for this alternative would be less than for STP, Units 1 and 2; and 

pollutants would dissipate with the Colorado River (minimizing exposure concentrations to 

aquatic resources). Therefore, impacts on aquatic ecology would be SMALL.

8.3.5 Terrestrial Ecology

Coal-fired operations would affect terrestrial ecology both on the STP site and in offsite coal 

mining areas.

If the coal-fired alternative is constructed at the STP site, construction would likely affect a 

variety of habitats and land uses, including industrial land (buildings, parking areas, and 

mowed-maintained fields), drainage ditches, scattered small palustrine wetlands, scrub-shrub 

habitat, and mixed grassland habitat where abandoned farm lands previously existed prior to 

construction of Units 1 and 2. Most of these areas have been mildly to extensively disturbed 

during the construction and operations of Units 1 and 2 and other human activities. After the 

completion of the new units, construction crews would likely grade, landscape, and replant the 

areas used for temporary building support, which is similar to what STPNOC proposed to do 

after completion of proposed new nuclear Units 3 and 4 (STPNOC 2010b). The majority of 

permanently affected areas would be maintained (e.g., mowed) and industrial areas. The plant 

operator would likely implement BMPs to minimize impacts to wetlands. The plant operator 

would be required to comply with the USACE’s 404 permits. Construction activities could also 

adversely affect onsite wildlife through noise, increased light pollution, and increased traffic. 

However, these impacts would be temporary and minor.

Coal mining would affect terrestrial resources at offsite coals mines, although much of this land 

is likely already disturbed by mining, and the incremental effects of this alternative on coal mine 

terrestrial ecology are difficult to gauge.

STPNOC estimates that 253,000 tons of coal ash and 88,000 tons of scrubber sludge would be 

disposed of on site annually (STPNOC 2010a). Over a 40-year period, this would require 

approximately 200 ac for land disposal (STPNOC 2010a). As described above, these areas 

could affect terrestrial ecology, especially if they are located in habitats that are currently used 

by wildlife on the STP site. Once the disposal area is reclaimed, the habitats may be useable 

by wildlife that inhabits open areas.

Deposition of acid rain resulting from nitrogen or sulfur oxide emissions, and the deposition of 

other pollutants, can also affect terrestrial ecology both on and off site. Given the emission 

regulations discussed in Section 8.3.1, air deposition impacts may be noticeable but are unlikely

to be destabilizing.

Because of the potential habitat disturbances and potential pollutant deposition, impacts to 

terrestrial resources from a coal-fired alternative would be MODERATE.

8.3.6 Human Health

Coal-fired power plants introduce worker risks from coal and limestone mining, coal and 

limestone transportation, plant operations, and disposal of coal combustion and scrubber 

wastes. In addition, there are public risks from the inhalation of stack emissions (as addressed 

in Section 8.3.1) and the secondary effects of eating foods grown in areas subject to deposition 

from plant stacks.
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Human health risks of coal-fired power plants are described, in general, in Table 8–2 of the 

GEIS (NRC 1996). Cancer and emphysema, as a result of the inhalation of toxins and 

particulates, are identified as potential health risks to occupational workers and members of the 

public (NRC 1996). The human health risks of coal-fired power plants, both to occupational 

workers and to members of the public, are greater than those of the current STP due to 

exposures to chemicals such as mercury; sulfur oxides; nitrogen oxides; radioactive elements, 

such as uranium and thorium contained in coal and coal ash; and polycyclic aromatic 

hydrocarbon (PAH) compounds, including benzo(a)pyrene.

Regulations restricting emissions—enforced by EPA or state agencies—have acted to 

significantly reduce potential health effects but do not entirely eliminate them. These agencies 

also impose site-specific emission limits as needed to protect human health. Even if the 

coal-fired alternative were located in a non-attainment area, emission controls and trading or 

offset mechanisms could prevent further regional degradation; however, local effects could be 

visible. Many of the byproducts of coal combustion responsible for health effects are largely 

controlled, captured, or converted in modern power plants (as described in Section 8.3.1), 

although some level of health effects may remain.

Aside from emission impacts, the coal-fired alternative introduces the risk of coal pile fires, and 

for those plants that use coal combustion liquid and sludge waste impoundments, the release of 

the waste due to a failure of the impoundment. Although there have been several instances of 

this occurring in recent years, these types of events are still relatively rare.

Despite the range of potential threats to human health, extensive health-based regulations exist 

to mitigate the risks to workers and the public. As a result, the NRC staff expects human health 

impacts to be characterized as SMALL.

Noise during construction activities and from plant operations may be detectable off site. The 

plant operator would need to adhere to local ordinances regarding maximum noise levels during

construction and operations. Therefore, impacts from noise would likely be SMALL.

8.3.7 Land Use

The GEIS generically evaluates the impact of constructing and operating various replacement 

power plant alternatives on land use, both on and off each plant site. The analysis of land use 

impacts focuses on the amount of land area that would be affected by the construction and 

operation of a supercritical coal-fired generation at the STP site.

Based on scaled GEIS estimates, the plant would require approximately 4,629 ac (1,873 ha) of 

land. STPNOC estimates that 353 ac (143 ha) of land would be required (STPNOC 2010a). 

This estimate appears reasonable; therefore, it is used for this analysis. STPNOC estimates 

that an additional 200 ac (80 ha) of land area would be required on site for waste disposal 

(STPNOC 2010a). Land would also be required on site for frequent coal and limestone 

deliveries by rail or barge.

Offsite land use impacts would occur from coal mining, in addition to land use impacts from the 

construction and operation of the new power plant. Scaling from GEIS estimates, approximately 

59,906 ac (24,244 ha) of land could be affected by mining coal and waste disposal to support 

the coal-fired alternative during its operational life (NRC 1996); however, most of the land in 

existing coal mining areas has already experienced some level of disturbance. The elimination 

of the need for uranium mining to supply fuel for the STP would partially offset this offsite land 

use impact. Scaling from GEIS estimates, approximately 2,560 ac (1,036 ha) would not be 

needed for mining and processing uranium during the operating life of the plant.
Environmental Impacts of Alternatives

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Since a substantial amount of onsite land at the STP site would be converted for coal and 

limestone delivery and waste disposal, land use impacts would be MODERATE. 

8.3.8 Socioeconomics

As previously discussed, socioeconomic impacts are defined in terms of changes to the 

demographic and economic characteristics and social condition of a region. For example, the 

number of jobs created by the construction and operation of a power plant could affect regional 

employment, income, and expenditures. Two types of jobs would be created by this alternative: 

(1) construction jobs, which are transient, short in duration, and less likely to have a long-term 

socioeconomic impact; and (2) power plant operation jobs, which have the greater potential for 

permanent, long-term socioeconomic impacts. Workforce requirements of power plant 

construction and operation for the coal-fired alternative were determined to measure their 

possible effects on current socioeconomic conditions.

Scaling from GEIS estimates, the construction workforce would peak at 6,808 workers. 

STPNOC projected a peak construction workforce of 3,955 employees (STPNOC 2010a). 

STPNOC’s estimate appears reasonable; therefore, it is used in this analysis. The relative 

economic impact of this many workers on the local economy and tax base would vary, with the 

greatest impacts occurring in the communities where the majority of construction workers would 

reside and spend their income. As a result, local communities could experience a short-term 

“boom” from increased tax revenue and income generated by construction expenditures and the 

increased demand for temporary (rental) housing and business services. Some construction 

workers could relocate to Matagorda and surrounding counties in order to be closer to the 

construction work site. However, given the proximity of STP to the Houston metropolitan area, 

many construction workers could commute to the STP site, thereby lessening the need for 

additional rental housing near STP. 

After completing the installation of the supercritical coal-fired power plant, local communities 

could experience a return to pre-construction economic conditions. Based on this information, 

and given the number of workers, socioeconomic impacts during construction in communities 

near the STP site could range from SMALL to MODERATE.

Scaling from GEIS estimates, the plant operation workforce would be 681 workers. STPNOC 

estimated a plant operation workforce of approximately 348 workers. The STPNOC estimate 

appears to be reasonable and is consistent with trends toward lowering labor costs by reducing 

the size of plant operations workforces. The amount of property taxes paid under the coal-fired 

alternative may increase if additional land is required off site to support this alternative. 

Socioeconomic impacts during operations could range from SMALL to MODERATE as the STP 

site transitions to the new supercritical coal-fired power plant. The potential reduction in overall 

employment at STP could affect property tax revenue and income in local communities and 

businesses. In addition, the permanent housing market could also experience increased 

vacancies and decreased prices if operations workers and their families move out of the region.

8.3.9 Transportation

Transportation impacts associated with construction and operation of a four-unit, coal-fired plant 

would consist of commuting workers and truck deliveries of construction materials to the STP 

site. During periods of peak construction activity, up to 3,955 workers could be commuting daily 

to the site (STPNOC 2010a). Workers commuting to the STP site would primarily use two-lane 

roads. The volume of traffic on these roads, especially FM 521, would increase substantially. 

In addition to commuting workers, trucks would be transporting construction materials and 

equipment to the worksite, thus increasing the amount of traffic on local roads. The increase in 
Environmental Impacts of Alternatives

8-36

vehicular traffic would peak during shift changes, resulting in temporary levels of service 

impacts and delays at intersections. Some power plant components and materials could also 

be delivered by train or barge. Train deliveries could cause additional traffic delays at railroad 

crossings. Based on this information, traffic-related transportation impacts during construction 

could range from MODERATE to LARGE. 

Traffic-related transportation impacts would be greatly reduced after completing the installation 

of the coal-fired units. Transportation impacts would include daily commuting by the operating 

workforce, equipment and materials deliveries, and the removal of commercial waste material to 

offsite disposal or recycling facilities by truck. During operations, the estimated number of 

operations workers commuting to and from the STP site would be 348 workers. Frequent 

deliveries of coal and limestone by rail would add to the overall transportation impact by causing 

traffic delays at railroad crossings. Onsite coal storage would make it possible to receive 

several trains per day. Limestone delivered by rail could also add additional traffic (though 

considerably less traffic than that generated by coal deliveries). Traffic-related transportation 

impacts would be considerably less than current operations because the new supercritical

coal-fired power plant would employ far fewer workers than STP, Units 1 and 2. Overall, 

transportation impacts would be SMALL during power plant operations.

8.3.10 Aesthetics

The analysis of aesthetic impacts focuses on the degree of contrast between the coal-fired 

alternative and the surrounding landscape and the visibility of the coal-fired power plant. During 

construction, all of the clearing and excavation would occur on the STP site. These activities 

may be visible from offsite roads, particularly FM 521. Since the STP site already appears 

industrial, construction of the coal-fired power plant would appear similar to onsite activities 

during refueling outages.

The coal-fired alternative would be up to 200 ft (61 m) tall with an exhaust stack up to 500 ft 

(152 m), which may be visible off site in daylight hours. The coal-fired plant, however, would be 

shorter and less noticeable than the current STP reactor building, which has a height of

approximately 250 ft (76 m) (STPNOC 2010b). Lighting on plant structures may be detectable 

off site. Noise generated during power plant operations would be limited to routine industrial 

processes and communications.

In general, given the industrial appearance of the STP site, the new coal-fired power plant would 

blend in with the surroundings if the existing STP, Units 1 and 2, remains. Aesthetic changes 

would be limited to the immediate vicinity of the existing STP site, and any impacts would be 

SMALL. 

8.3.11 Historic and Archaeological Resources

The same considerations, discussed in Section 8.1.11, for the impact of the construction of a 

new nuclear plant on historic and archaeological resources apply to the construction activities 

that would occur on the STP site for a coal-fired plant. As described in Section 2.2.10, much of 

the STP site has been previously disturbed by the construction of STP, Units 1 and 2. In 

addition, in preparation for the COL application for Units 3 and 4, STPNOC conducted a cultural

resources assessment of the STP site. STPNOC reviewed existing information for the STP site 

and the area within a 10-mi (16-km) radius. STPNOC concluded that any cultural resource sites 

that may have existed on site would no longer retain their integrity because the area was heavily 

disturbed during the construction of Units 1 and 2 (STPNOC 2010b). In December 2006, 

STPNOC reported these findings to the SHPO at the Texas Historical Commission. The SHPO 
Environmental Impacts of Alternatives

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concurred, in January 2007, that there would be no impacts to historic properties 

(STPNOC 2006; THC 2007).

There is a low potential for cultural resources to be located in previously undisturbed portions of 

the STP site. However, if the coal-fired units were to be sited within undisturbed areas or within 

areas of known cultural sensitivity (historic grave site located on the property and described in 

Section 2.2.10), these areas would need to be surveyed by a professional archaeologist to 

identify and develop possible mitigation measures to address any adverse effects from project 

activities. NRC assumes the plant operator would follow similar procedures to those described 

in the final EIS for STP, Units 3 and 4 (NRC 2011), if the plant operator discovered any historic 

or cultural resources during ground-disturbing activities associated with building the new units.

The NRC staff determined that the impact of the coal-fired alternative at the STP site on historic 

and archaeological resources would be SMALL for the following reasons:

• NRC (2011) and STPNOC (2010a, 2010b) did not identify any cultural 

resources that could be affected by Units 3 and 4. 

• The SHPO determined that construction for Units 3 and 4 would not affect 

cultural and historic resources. 

• NRC assumes that the plant operator would follow environmental compliance 

procedures for new ground-disturbing activities.

8.3.12 Environmental Justice

The environmental justice impact analysis evaluates the potential for disproportionately high and 

adverse human health, environmental, and socioeconomic effects on minority and low-income 

populations that could result from the construction and operation of a new power plant. As 

previously discussed in Section 8.1.12, such effects may include human health, biological, 

cultural, economic, or social impacts. Some of these potential effects have been identified in 

resource areas discussed in this SEIS. For example, increased demand for rental housing 

during plant construction could disproportionately affect low-income populations. Minority and 

low-income populations are subsets of the general public residing in the vicinity of the STP site, 

and all are exposed to the same hazards generated from constructing and operating a new 

coal-fired plant. Section 4.9.7, “Environmental Justice,” presents demographic information 

about minority and low-income populations residing in the vicinity of the STP site. 

Potential impacts to minority and low-income populations from the construction and operation of 

a new coal-fired plant at the STP site would mostly consist of environmental and socioeconomic 

effects (e.g., noise, dust, traffic, employment, and housing impacts). Noise and dust impacts 

during construction would be short-term and primarily limited to onsite activities. Minority and 

low-income populations residing along site access roads would be directly affected by increased 

commuter vehicle and truck traffic. However, because of the temporary nature of construction, 

these effects would only occur during certain hours of the day and are unlikely to be high and 

adverse. Increased demand for rental housing during construction could affect low-income 

populations living near STP. However, given the proximity of the STP site to the Houston 

metropolitan areas, many construction workers could commute to the STP site, thereby 

lessening the additional need for rental housing.

Based on this information, and the analysis of human health and environmental impacts 

presented in this SEIS, the construction and operation of a new coal-fired power plant would not 

have disproportionately high and adverse human health and environmental effects on minority 

and low-income populations residing in the vicinity of the STP site. 
Environmental Impacts of Alternatives

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8.3.13 Waste Management

During the construction stage of the coal-fired alternative, land clearing and other construction 

activities would generate waste that could be recycled, disposed of on site, or shipped to an 

offsite waste disposal facility. Because the alternative would be constructed on or near the 

previously disturbed STP site, the amounts of waste produced during land clearing would be 

reduced.

Coal combustion generates several waste streams including ash (a dry solid) and sludge (a 

semi-solid by-product of emission control system operation). This coal-fired alternative would 

produce roughly 446,000 tons (405,000 MT) of ash, and 43 percent (193,000 tons 

(175,000 MT)) of the ash would be recycled for beneficial use (STPNOC 2010a). 

STPNOC (2010a) estimated that approximately 88,000 tons (80,000 MT) of scrubber sludge 

would be disposed of on site each year, which was based on an assumed annual lime usage of 

approximately 107,000 tons (97 MT). Approximately 200 ac (81 ha) would be required to 

dispose of the ash and scrubber waste on site over a 40-year plant life (STPNOC 2010a). All 

waste disposal would occur on site.

The impacts from waste generated during operation of this coal-fired alternative would be 

MODERATE because the impacts would be clearly visible but would not destabilize important 

resources.

8.3.14 Summary of Impacts for the Supercritical Coal-Fired Generation Alternative

Table 8–4 provides a summary of the environmental impacts of the supercritical coal-fired 

alternative compared to continued operation of STP.

Table 8–4. Summary of Environmental Impacts of the Supercritical Coal-Fired 

Alternative Compared to Continued Operation of STP, Units 1 and 2 

Supercritical Coal-Fired 

Generation Continued STP Operation

Air quality MODERATE SMALL

Surface water SMALL SMALL

Groundwater SMALL SMALL

Aquatic resources SMALL SMALL

Terrestrial resources MODERATE SMALL

Human health SMALL SMALL to MODERATE

Land use MODERATE SMALL

Socioeconomics SMALL to MODERATE SMALL

Transportation SMALL to LARGE SMALL

Aesthetics SMALL SMALL

Historic & archaeological SMALL SMALL

Waste management MODERATE SMALL
Environmental Impacts of Alternatives

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8.4 Combination Alternative

In this section, the NRC staff evaluates the environmental impacts of a combination of 

alternatives. This combination includes 640 MWe supplied by one NGCC unit similar to the 

units identified in Section 8.2, 1,620 MWe supplied by wind energy projects, and 300 MWe of 

energy conservation and efficiency (also known as demand-side management). Because wind 

is an intermittent resource, wind energy projects would be interconnected to one another on the 

transmission grid, and the NGCC unit could be used, if needed, to be a baseload resource. 

Interconnecting wind farms through the transmission grid increase the probability that at least

one site experiences sufficient wind to produce electricity. Thus, as more sites are added to the 

transmission grid, the interconnected wind farms provide electricity that is comparable to a 

single wind farm providing near constant deliverable wind power. Archer and Jacobson (2007) 

looked at 19 wind energy sites in the southeast, including 2 sites in Texas, and determined that 

the 19 interconnected wind farms could guarantee 312 kWe of power for 79 percent of time. 

Based on this data, NRC assumed that to provide 1,620 MWe of wind energy, the installed 

capacity would need to be at least 7,714 MWe. NRC included this contribution from wind power 

because Texas has significant wind energy resources and leads the Nation in wind-powered 

generation capacity. As of June 30, 2011, the installed wind capacity in Texas was 

10,135 MWe (DOE 2011b). In addition, wind energy projects totaling 36,124 MWe are currently 

under ERCOT’s review (ERCOT 2011a), and the installed wind capacity in Texas has been 

increasing annually by 500 MWe to 3,000 MWe in each of the past 7 years (DOE 2011b). 

Therefore, NRC considers 1,620 MWe of wind energy (with an installed capacity of 7,714 MWe) 

to be a reasonable amount by the time the STP licenses expire in 2027 and 2028. Section 8.6.3 

discusses the status of wind energy technology and implementation in greater detail.

NRC assumed that one new NGCC unit of the type described in Section 8.2 would be 

constructed and installed at the STP site with a total capacity of 640 MWe. The appearance of 

an NGCC unit would be similar to that of the full NGCC alternative considered in Section 8.2, 

although only one unit would be constructed. The NRC estimates that it would require about 

one-fourth of the space necessary for the alternative considered in Section 8.2 and that 

construction and operational effects would scale accordingly.

NRC assumed that the wind turbines could be constructed at multiple sites scattered over large 

distances to minimize the likelihood that all sites would be exposed to the same weather events 

at the same time. Some of these sites could potentially be offshore, although no turbines 

currently operate offshore anywhere in the U.S. NRC assumed that the contribution from 

offshore wind energy would be relatively small because offshore wind capacity of the magnitude 

analyzed in this alternative exceeds by a factor of 10 or more the amount of offshore wind 

projected by the EIA for the entire U.S. by the year 2035 (EIA 2011a). Assuming each turbine 

has a capacity of 2 MWe, construction and operation of approximately 3,877 turbines would be 

required. In addition, new transmission lines would likely be needed to connect the wind energy 

projects to one another and the distribution system.

STPNOC estimated that a utility-scale wind plant requires 60 ac of land per MWe of installed 

capacity in open, flat terrain (STPNOC 2010a). Approximately 462,900 ac (187,300 ha) of land 

would be required for the installed capacity of 7,714 MWe. A small percentage of this area 

would be occupied by turbines, access roads, and other infrastructure, with the rest of the area 

potentially available for compatible other uses, such as agriculture. For example, NREL (2009) 

estimates that 0.7 ha (1.7 ac) of land would be temporarily disturbed per MWe of installed 

capacity and that 0.3 ha (0.7 ac) of land would be permanently disturbed per MWe of installed 

capacity. For this alternative, approximately 2,185 ac (884 ha) would be temporarily disturbed, 

and 937 ac (379 ha) would be permanently disturbed.
Environmental Impacts of Alternatives

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For the combination alternative, the NRC assumed that an Energy Efficiency and Conservation 

Program would replace 300 MWe of current STP output. As discussed in Section 8.6.2, 

beginning in 2009, all electric transmission and distribution utilities within the ERCOT market—

including CPS Energy and Austin Energy (two of the owners of STP, Units 1 and 2)—were 

required to implement energy efficiency and conservation programs to reduce their customers’ 

energy consumption by a minimum of 20 percent of the utility’s annual growth in 2009, 

25 percent in 2012, and 30 percent in 2013 and beyond. CPS Energy and Austin Energy 

currently implement programs to promote energy efficiency and conservation. The 300 MWe

reduction in energy use for this alternative would be beyond the required energy efficiency and 

conservation programs currently implemented by CPS Energy and Austin Energy. No major 

construction would be necessary for the energy efficiency and conservation component of the 

combination alternative.

8.4.1 Air Quality

As discussed in Section 2.2.2.1, the STP site is located in central Matagorda County, Texas, at 

the southern edge of the Metropolitan Houston–Galveston Intrastate Air Quality Control Region 

(40 CFR 81.38). The Corpus Christi–Victoria Intrastate Air Quality Control Region 

(40 CFR 81.136) lies immediately south and west of Matagorda County. EPA has designated 

all of the counties in these Air Quality Control Regions adjacent to the STP site as in compliance 

with the National Ambient Air Quality Standards (40 CFR 81.344) except Brazoria County to the 

north; Brazoria County is classified Nonattainment/Severe relative to the 8-hour ozone standard 

(EPA 2011b). 

Construction activities for both the NGCC plant and wind energy components would cause 

some localized temporary air quality effects because of equipment emissions and fugitive dust 

from operation of earth-moving and material-handling equipment. Emissions from workers’ 

vehicles and motorized construction equipment exhaust would be temporary. NRC assumed 

that construction crews would use dust-control practices to control and reduce fugitive dust 

because §111.145 of TCEQ’s regulations require dust suppression control during the 

construction of facilities and parking lots. Impacts from wind turbine installation would be 

spread across multiple locations, but these impacts would be short in duration. In its 

programmatic final EIS, which analyzed the impacts of offshore wind projects generically within

U.S. waters, U.S. Minerals Management Service (MMS, which is currently Bureau of Ocean 

Energy Management) determined that construction of offshore wind projects could result in air 

quality impacts, mainly from fugitive dust emissions, and emissions of sulfur dioxide and ozone 

precursors (MMS 2007).

New air emission sources in Texas must comply with Federal, Texas, and local air quality 

control laws. The NGCC component of this combination alternative would qualify as a new 

major-emitting industrial facility and would be subject to PSD requirements under CAA 

(EPA 2011c). The NGCC unit would need to comply with the standards of performance for 

electric utility steam generating units set forth in 40 CFR Part 60 Subpart KKKK. The plant 

would also require an operating permit from TCEQ.

Subpart P of 40 CFR Part 51 contains the visibility protection regulatory requirements, including 

the review of new sources that would be constructed in the attainment or unclassified areas and 

may affect visibility in any Federal Class I area. If an NGCC plant was located close to a 

mandatory Class I area, additional air pollution control requirements would be required. As 

noted in Section 2.2.2.1, there are no mandatory Class I Federal areas within 50 mi of the STP 

site.
Environmental Impacts of Alternatives

8-41

The NRC projects the following emissions, assuming a maximum of 640 MWe power from the 

NGCC component of this combination alternative based on data published by the EIA, EPA, and 

on performance characteristics and emissions controls:

• sulfur oxides—50 tons (46 MT) per year, 

• nitrogen oxides—219 tons (199 MT) per year, 

• carbon dioxide—1,727,000 tons (1,567,000 MT) per year, 

• carbon monoxide—222 tons (201 MT) per year, 

• TSP—97 tons (88 MT) per year, and

• particulate matter PM10—97 tons (88 MT) per year. 

During operations, the wind energy projects would not produce emissions. However, workforce 

transportation and eventual decommissioning could result in carbon dioxide emissions.

For the Energy Efficiency and Conservation Program, the GEIS notes that the environmental 

impacts are likely to be centered on indoor air quality (NRC 1996). This is due to increased 

weatherization of the home in the form of extra insulation and reduced air turnover rates from 

the reduction in air leaks. However, the actual impact is highly site-specific and not yet 

well-established.

8.4.1.1 Sulfur Oxide and Nitrogen Oxide

The new NGCC plant would have to comply with Title IV of the CAA (42 USC 7651) reduction 

requirements for sulfur and nitrogen oxides, which are the main precursors of acid rain and the 

major cause of reduced visibility. Title IV establishes maximum sulfur and nitrogen oxide

emission rates from existing plants and a system of sulfur oxide emission allowances that can 

be used, sold, or saved for future use by new plants. In addition, in August 2011, EPA 

published the Cross-State Air Pollution Rule, which included reductions of sulfur and nitrogen 

oxides in Texas. According to the rule, NGCC plants would need to comply with the new 

reductions by 2012.

As stated above, the new NGCC plant would produce 50 tons (46 MT) per year of sulfur oxides 

and 219 tons (199 MT) per year of nitrogen oxides based on the use of the dry low-nitrogen 

oxide combustion technology and use of SCR to significantly reduce nitrogen oxide emissions. 

The new plant would be subjected to the continuous monitoring requirements for sulfur and 

nitrogen oxides. The current SIP for Texas includes a Cap and Trade Program for sulfur and 

nitrogen oxide emissions. To operate the NGCC plant, the plant operator would have to 

purchase sulfur dioxide allowances from the open market or shut down existing fossil-fired 

plant(s) and apply the credits to the new plant (STPNOC 2010a). Thus, provided the plant 

operator is able to purchase sufficient allowances to operate, the NGCC portion of this 

alternative would not add to net regional sulfur dioxide or nitrogen oxide emissions, although it 

might do so locally.

8.4.1.2 Greenhouse Gases

The new plant would release greenhouse gases, such as carbon dioxide and methane. The 

plant would be subjected to the continuous monitoring requirements for carbon dioxide, as 

specified in 40 CFR Part 75. The NGCC plant would emit approximately 1.7 million tons

(approximately 1.6 million MT) per year of carbon dioxide emissions.

On July 12, 2012, EPA issued a final rule tailoring the applicability criteria that determine which

stationary sources and modification to existing projects become subject to permitting 

requirements for greenhouse emissions under the PSD and Title V Programs of the CAA
Environmental Impacts of Alternatives

8-42

(77 FR 41051). According to the Tailoring Rule, greenhouse gases are a regulated new source 

review pollutant under the PSD major source permitting program if the source is otherwise 

subject to PSD (for another regulated new source review pollutant) and has a greenhouse gas 

potential to emit equal to or greater than 75,000 tons (68,000 MT) per year of carbon dioxide 

equivalent (“carbon dioxide equivalent” adjusting for different global warming potentials for 

different greenhouse gases). Such sources would be subject to BACT, although EPA has yet to 

determine BACT for greenhouse gases.

EPA issued a FIP on May 3, 2011, to permit greenhouse gas-emitting sources in states that do 

not have measures to lower greenhouse gases in their SIP. Because Texas has not updated its 

SIP to include greenhouse gases, EPA will be the official permitting authority for greenhouse 

gas-emitting sources in Texas if the SIP is not updated before the NGCC plant begins 

operations.

8.4.1.3 Particulates

The new NGCC plant would produce 97 tons (88 MT) per year of TSP, all of which would be 

emitted as PM10. STPNOC (2010a) indicated that all PM10 emissions would be PM2.5. 

DOE (2007) evaluated the emissions from a hypothetical 560 MWe NGCC unit using BACT to 

meet the emission requirements of the 2006 New Source Performance Standards. DOE 

concluded that emissions from particulates would be negligible because NGCC use natural gas 

as fuel; therefore, NGCC plants would not require emissions controls equipment or features to 

reduce these emissions.

8.4.1.4 Hazardous Air Pollutants

In December 2000, EPA issued regulatory findings (65 FR 79825) on emissions of HAPs from 

electric utility steam-generating units, which said that natural gas-fired plants emit HAPs such as 

arsenic, formaldehyde, and nickel, and stated the following: 

Also in the utility RTC (Report to Congress), the EPA indicated that the impacts 

due to HAP emissions from natural gas-fired electric utility steam generating 

units were negligible based on the results of the study. The Administrator finds 

that regulation of HAP emissions from natural gas-fired electric utility steam 

generating units is not appropriate or necessary.

As a result of EPA’s conclusion, the NRC staff finds no significant air quality effects from HAPs 

from the NGCC component of this alternative. The wind and energy efficiency and conservation 

components of this alternative release no HAPs.

8.4.1.5 Conclusion

Based on the NRC staff’s analysis, the overall air quality impacts of a combination alternative 

that includes a new NGCC plant located at the STP site, wind energy projects, and the Energy 

Efficiency and Conservation Program would be SMALL to MODERATE. Emissions from the 

wind energy projects and the Energy Efficiency and Conservation Program would not be 

noticeable. Emissions from the NGCC portion of this alternative would be noticeable for 

greenhouse gases; carbon dioxide emissions would be two orders of magnitude larger than the 

threshold in EPA’s tailoring rule for greenhouse gas (75,000 tons (68,000 MT) per year of 

carbon dioxide equivalent) that would trigger a regulated new source review. Impacts would not 

be noticeable for sulfur and nitrogen oxides because the Texas SIP requires a Cap and Trade 

Program, and there would be no net increase in sulfur and nitrogen oxide emissions. Based on 

analyses from DOE (2007) and EPA (2000, 65 FR 79825), TSPs and HAPs from the NGCC unit 

would have negligible impacts.
Environmental Impacts of Alternatives

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8.4.2 Surface Water Resources

STPNOC did not propose using any surface water during the construction of Units 3 and 4 

(NRC 2011). Because a single NGCC unit occupies a smaller footprint, and its construction 

would entail substantially less excavation and earthwork at the STP site as compared to Units 3 

and 4, NRC expects that surface water would not be used during construction for the NGCC 

component of this alternative.

As further described in Section 8.5.2 for the NGCC alternative, some temporary impacts to 

surface water quality may result from dredging activities in the Colorado River near the barge 

slip and from increased sediment loading in stormwater runoff from active construction areas. 

These activities would be conducted under a permit from the USACE requiring the 

implementation of BMPs to minimize impacts. Runoff from construction areas would be 

controlled under a State-issued TPDES general permit that would require implementation of a 

stormwater pollution prevention plan and associated BMPs.

Small amounts of water would be required during the construction phase for each of the 

3,877 wind turbines for dust suppression and compaction during site clearing and for concrete 

production for pad and piling construction, as appropriate. Although surface water from nearby 

water bodies may be used for pad site construction at some locations, it is likely that water 

would be procured from offsite sources and trucked to the point of use on an as needed basis. 

Use of ready-mix concrete would also reduce the need for onsite use of nearby water sources.

Further, the installation of land-based wind turbines would require installation of access roads 

and possibly transmission lines (especially for turbine sites not already proximal to transmission 

line corridors). Access road construction would also require some water for dust suppression 

and roadbed compaction and would have the potential to result in soil erosion and stormwater 

runoff from cleared areas. Water would likely be trucked to the point of use from offsite 

locations along with road construction materials. Construction activities would be conducted in 

accordance with State-issued TPDES or equivalent permits for stormwater discharges 

associated with construction activity, which would require the implementation of appropriate 

BMPs to prevent or mitigate water quality impacts.

Construction of offshore wind turbines, including the offshore foundation and pilings, associated 

anchoring devices, undersea cables, and onshore support installation (e.g., transformers) would 

also have the potential to cause water quality impacts due to soil and sediment erosion and 

runoff. Most notably, potential impacts would include disturbance of marine sediments from pile 

driving and erection of cofferdams for the wind turbine superstructures. Nevertheless, such 

water quality impacts would be temporary, and activities would be conducted in accordance with 

USACE and other applicable permits and requiring the use of BMPs to minimize impacts.

For facility operations, the NGCC component of this alternative would require about one-fourth 

of the water required by the NGCC alternative. It is expected that use of the existing intake and 

discharge infrastructure on the MCR and the Colorado River would be sufficient to support the 

NGCC plant. Surface water withdrawals would be subject to, and would remain well within, 

STPNOC’s existing water rights, and effluent discharges and stormwater discharges associated 

with industrial activity would be subject to a revised State-issued TPDES permit under this 

alternative. To support operations of individual wind turbine installations, only very small 

amounts of water would be used to periodically clean turbine blades and motors as part of 

routine servicing. It would be expected that water would be trucked to the point of use and 

procured from nearby sources.

Implementation of the Energy Efficiency and Conservation Program component of this 

alternative would likely entail little or no impact on surface water resources.
Environmental Impacts of Alternatives

8-44

In consideration of the information above, the impacts on surface water use and quality from 

construction and operations under the combination alternative would be SMALL.

8.4.3 Groundwater Resources

For the single NGCC plant at the STP site, construction-related ground disturbance and 

excavation work would be substantially less than that described for the NGCC alternative. 

Although groundwater dewatering of foundation excavations for a new NGCC plant would likely 

be required, slurry walls and wells were proposed for use to minimize potential adverse effects 

from dewatering both on site and off site (NRC 2011). Groundwater dewatering, where 

required, for installation of wind turbines on land, would be minimal due to the small footprint of 

foundation structures. For all construction activities, appropriate BMPs, including spill 

prevention practices, would be employed during wind turbine construction to prevent or 

minimize impacts on groundwater quality.

For NGCC plant operations, NRC assumed that the NGCC alternative would entail the same 

relative ratio of groundwater use to surface water use as that used at STP, Units 1 and 2. As 

such, for a single NGCC unit, groundwater use would be about one-fourth of the water required 

by the NGCC alternative and easily supported by existing onsite groundwater production wells

at STP. Little or no groundwater use would be expected for operation of wind turbines.

Implementation of the Energy Efficiency and Conservation Program component of this 

alternative would likely entail little or no impact on groundwater resources.

Based on this information, the overall impact on groundwater use and quality from construction 

and operations under the combination alternative would be SMALL.

8.4.4 Aquatic Ecology

Construction activities for the NGCC plant and land-based wind power projects (such as 

construction of heavy haul roads and support facilities) could affect drainage areas or other 

onsite aquatic features due to site runoff. NRC assumed that the plant operator would install 

temporary and permanent erosion and sediment control measures to minimize the flow of 

disturbed soils into ditches and wetlands. Such BMPs would likely be described in a TPDES 

general permit relating to stormwater discharges for construction activities.

To bring new materials to the STP site for the NGCC plant, NRC assumed the plant operator 

would dredge near the barge slip to transport some materials using barges. Permits and 

certifications from the USACE and other agencies would require the implementation of BMPs to 

minimize impacts. Due to the short-term nature of the dredging activities, the hydrological 

alterations to aquatic habitats would be localized and temporary.

During operations, the NGCC plant would require approximately one-fourth of the cooling water 

to be withdrawn from the Colorado River than the NGCC alternative analyzed in Section 8.2, 

and the thermal discharge would similarly be smaller. Therefore, the number of fish and other 

aquatic organisms affected by impingement, entrainment, and thermal impacts would be less for 

the combination alternative than for license renewal and the NGCC alternative. The cooling 

system for a new NGCC plant would have similar chemical discharges as STP, but the air 

emissions from the NGCC plant would emit particulates that would settle onto the river surface 

and introduce a new source of pollutants that would not exist if STP continued operating. 

However, the flow of the Colorado River would dissipate pollutants, which would minimize the 

exposure of fish and other aquatic organisms to pollutants.
Environmental Impacts of Alternatives

8-45

Construction and operation of offshore wind projects could affect aquatic communities. In its 

programmatic final EIS, MMS determined that construction and operations could have moderate 

impacts to aquatic organisms due to pile driving for installation of the structures, removal of 

structures by cutting or the use of explosives, and vessel traffic to and from the site 

(MMS 2007). Organisms most likely to be affected would be marine mammals, sea turtles, and 

fish due to noise from pile driving and vessel traffic as well as benthic organisms and habitats 

that are directly affected during site preparation. Siting offshore wind projects away from 

biologically productive areas could minimize such impacts. During operations, impacts from a 

spill as a consequence of a vessel collision could be moderate to major (MMS 2007).

Because little water use would be required as part of the Energy Efficiency and Conservation 

Program component of this alternative, impacts from the Energy Efficiency and Conservation 

Program on aquatic resources would likely be minimal.

Because of the potential habitat disturbances and noticeable impacts on aquatic organisms 

during construction and operation of offshore wind projects, impacts on aquatic resources from 

the combination alternative would be SMALL to MODERATE. Impacts from the NGCC portion 

of the alternative and Energy Efficiency and Conservation Program would not be noticeable 

because less water withdrawal and discharge would be required than for STP, Units 1 and 2. In 

addition, for the NGCC portion of the alternative, the construction activities would require BMPs, 

dredging would be short-term, and pollutants would dissipate without the Colorado River 

(minimizing exposure concentrations to aquatic resources).

8.4.5 Terrestrial Ecology

Constructing the NGCC plant would require approximately 92 ac (37 ha), which includes a new 

pipeline that would run approximately 2 mi (3 km) from the STP site to an existing pipeline. 

These estimates are based on GEIS scaling factors and details provided by STPNOC in its ER 

(STPNOC 2010a). Impacts on terrestrial ecology from onsite construction of the one NGCC unit 

would be less than the impacts described for the four-unit NGCC alternative, which are 

described in Section 8.2.

STPNOC estimated that a utility-scale wind plant requires 60 ac of land per MWe of installed 

capacity in open, flat terrain (STPNOC 2010a). Approximately 462,900 ac (187,300 ha) of land 

would be required for the installed capacity of 7,714 MWe. Of this area, approximately 2,186 ac 

(884 ha) would be temporarily disturbed during construction activities, and 937 ac (379 ha) 

would be permanently disturbed during operations. The permanently disturbed area would be 

filled with turbines, access roads, and other infrastructure, and the rest of the area would 

potentially be available for compatible other uses, such as agriculture (ranch, pasture, or 

cropland).

Impacts on terrestrial ecology from construction of the wind projects, including new transmission 

lines, could include loss of terrestrial habitat, an increase in habitat fragmentation, and 

corresponding increase in edge habitat, which may affect threatened and endangered species. 

Construction and operations of wind power projects could result in increased mortality of birds 

flying along the Trans-Gulf migratory route and might also cause increased mortality of 

migratory and resident bats. Offshore wind power development would also affect avian and 

aquatic resources. MMS (2007) determined that populations of marine and coastal birds as well 

as migrating inland birds may experience minor to potentially major impacts due to turbine 

collisions offshore and that endangered species would be the most impacted.

For this combination alternative, construction of the (a) 2-mi (3-km) natural gas pipeline and 

(b) transmission lines to connect the wind projects to distribution systems could result in habitat 

fragmentation and avian collisions with transmission lines. Depending on the length of new 
Environmental Impacts of Alternatives

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transmission lines, impacts could potentially destabilize attributes of the terrestrial ecosystem 

because the transmission lines could permanently convert forested or cover habitats into open, 

maintained areas. To the extent possible, STPNOC would route the pipeline through previously 

disturbed areas (STPNOC 2010a). Threatened and endangered species may also be affected 

by construction of the natural gas pipeline and new transmission lines. Long-linear projects, 

such as pipelines and transmission lines, can often be sited to avoid sensitive areas.

Because no construction would occur for the Energy Efficiency and Conservation Program, 

impacts from the Energy Efficiency and Conservation Program on terrestrial resources would 

likely be minimal. Wind energy projects could have a noticeable impact on avian and bat 

communities because wind energy projects in the Trans-Gulf migratory route could result in 

increased mortality of migratory and resident birds and bats. Building new transmission lines 

would also increase habitat fragmentation. Offshore wind power could also result in increased 

mortality of coastal birds. Based on this information, impacts on terrestrial resources would be 

MODERATE. 

8.4.6 Human Health

The human health risks from a combination of alternatives include the effects already discussed 

in Section 8.2.6 for the NGCC plant. However, the effects would be slightly less since one, 

rather than four, NGCC unit would be constructed and operated. For wind power, the GEIS 

notes that, except for a potential small number of occupational injuries, routine operations would 

not affect human health. For the Energy Efficiency and Conservation Program, the GEIS notes 

that the environmental impacts are likely to be centered on indoor air quality (NRC 1996). This 

is due to increased weatherization of the home in the form of extra insulation and reduced air 

turnover rates from the reduction in air leaks. However, the actual impact is highly site-specific 

and not yet well-established. Overall, human health risks to occupational workers and to 

members of the public from the combination alternative would likely be SMALL.

Noise during operations of NGCC plant would be limited to industrial processes and 

communications. Pipelines delivering natural gas fuel could be audible off site near compressor 

stations. Pipeline companies would need to adhere to local ordinances regarding maximum 

noise levels during construction and at compressor stations. Noise from the wind energy project 

would be audible in the immediate area but would likely be unobtrusive. Some noise impacts 

could occur in instances of energy conservation and efficiency upgrades to major building 

systems, but this impact would be intermittent and short-lived. Therefore, impacts from noise 

would likely be SMALL.

8.4.7 Land Use

The GEIS generically evaluates the impact of constructing and operating various replacement 

power plant alternatives on land use, both on and off each plant site. The analysis of land-use 

impacts focuses on the amount of land area that would be affected by the construction and 

operation of a single-unit NGCC plant at the STP site, wind energy projects, and energy 

conservation and efficiency.

Based on scaled GEIS estimates, constructing the single-unit NGCC unit would require 

approximately 92 ac (37 ha) at the STP site. This amount of land use would include other plant 

structures and associated infrastructure, such as the new 2-mi (3-km) pipeline, and is unlikely to 

exceed 92 ac (37 ha), excluding land for natural gas wells and collection stations.

In addition to onsite land requirements, land would be required off site for natural gas wells and 

collection stations. Scaling from GEIS estimates, approximately 2,400 ac (970 ha) would be 
Environmental Impacts of Alternatives

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required for wells and collection stations to bring the natural gas to the power plant. Most of this 

land requirement would occur on land where natural gas extraction already occurs.

STPNOC estimated that utility-scale, land-based wind energy projects would require 60 ac of 

land per MWe of installed capacity in open, flat terrain (STPNOC 2010a). Approximately 

462,900 ac (187,300 ha) of land would be required for the installed capacity of 7,714 MWe. Of 

this area of land, approximately 2,186 ac (884 ha) would be temporarily disturbed during 

construction activities, and 937 ac (379 ha) would be permanently used for each wind turbine

during operations. Land used for the wind energy projects would be filled with turbines, access 

roads, and other infrastructure, and the rest of the land area between the turbines would be 

available for other uses, such as agriculture (ranch, pasture, or cropland).

Offshore wind energy projects would need to avoid impeding navigation. For both land-based 

and offshore wind projects, new electrical transmission systems would need to be built to 

connect the wind energy projects to the electric distribution system. 

The elimination of uranium fuel for STP could partially offset offsite land requirements for other 

energy projects. Scaling from GEIS estimates, approximately 2,560 ac (1,036 ha) would no 

longer be needed for the mining and processing of uranium. 

The land use impacts of the Energy Efficiency and Conservation Program would be minimal. 

The rapid replacement and disposal of older inefficient appliances and other equipment would 

generate waste material and could increase the size of landfills; however, given the time for 

program development and implementation, the cost of replacements, and the average life of 

equipment, the replacement process would probably be gradual. More efficient appliances and 

equipment would replace older equipment (especially in the case of frequently replaced items, 

such as light bulbs). In addition, many items (such as home appliances and industrial 

equipment) have recycling value and would not be disposed of in landfills.

The wind energy portion of this combination alternative would require a substantial amount of 

open land, although only a small portion would be used for wind turbines, access roads, and 

infrastructure. Therefore, land use impacts from the combination alternative could range from 

SMALL to MODERATE.

8.4.8 Socioeconomics

As previously discussed, socioeconomic impacts are defined in terms of changes to the 

demographic and economic characteristics and social conditions of a region. For example, the 

number of jobs created by the construction and operation of a new NGCC plant and wind power 

projects could affect regional employment, income, and expenditures. Two types of jobs would 

be created by this alternative: (1) construction jobs, which are transient, short in duration, and 

less likely to have a long-term socioeconomic impact; and (2) power plant and wind energy 

operation jobs, which have the greater potential for permanent, long-term socioeconomic 

impacts. Workforce requirements for the construction and operation of the combination 

alternative were evaluated to measure their possible effects on current socioeconomic 

conditions.

Based on GEIS estimates, the construction workforce would be up to 800 (maximum) workers 

for the NGCC plant. Scaling from STPNOC’s estimates, the estimated construction workforce 

would be up to 507 (maximum) workers (STPNOC 2010a). STPNOC’s estimate appears 

reasonable; therefore, it is used in this analysis. STPNOC did not provide a construction 

workforce estimate for wind energy projects. In Exelon Generation Company’s, LLC (Exelon)

ER for Limerick Generating Station, Exelon estimated a construction workforce of 200 for 

approximately half the amount of wind capacity needed for this combination alternative 
Environmental Impacts of Alternatives

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(Exelon 2011). This estimate includes both land-based and offshore wind energy projects. 

Scaling from this estimate, wind energy projects could require a construction workforce of up to 

400 workers. The relative economic impacts of this many workers on the local economy and tax 

base would vary, with the greatest impacts occurring in the communities where the majority of 

construction workers would reside and spend their income. As a result, local communities could 

experience a short-term economic “boom” from increased tax revenue and income generated by 

construction expenditures and the increased demand for temporary (rental) housing and 

business services. Some construction workers could relocate to Matagorda and surrounding 

counties in order to be closer to the construction work sites. However, given the proximity of 

STP to the Houston and other metropolitan areas, workers could commute to the various 

construction sites, thereby lessening the need for additional rental housing near STP. 

After completing the installation of the single NGCC unit and wind turbines, local communities 

could experience a return to pre-construction economic conditions. Based on this information, 

and the given number of workers, socioeconomic impacts during construction in communities 

near the STP site and wind farms could be SMALL, due to the small number of workers needed 

to construct the NGCC plant and because the wind energy project workers would be spread 

throughout the service region.

Scaled from GEIS estimates, the single-unit NGCC power plant operation workforce would be 

100 workers. Based on STPNOC’s estimates, the maximum NGCC operation workforce would 

be 23 workers (STPNOC 2010a). STPNOC’s estimate appears reasonable; therefore, it is used 

in this analysis. STPNOC did not provide an operations workforce estimate for wind energy 

projects. In Exelon’s ER for the Limerick Generating Station, Exelon estimated a wind energy

workforce of 50 workers for approximately half the amount of wind capacity needed for this 

combination alternative (Exelon 2011). This estimate includes both land-based and offshore 

wind energy projects. Scaling from this estimate, wind energy projects could require an 

operations workforce of up to 100 workers. The amount of property taxes paid under the 

combination alternative may increase if additional land is required off site to support this 

alternative. As noted in the GEIS, an Energy Conservation and Efficiency Program would also 

create jobs for additional workers (NRC 1996). Socioeconomic impacts during operations could 

range from SMALL to MODERATE as the STP site transitions to the new, single-unit NGCC 

power plant. The reduction in overall employment at STP could affect property tax revenue and 

income in local communities and businesses. In addition, the permanent housing market could 

also experience increased vacancies and decreased prices if operations workers and their 

families move out of the region.

8.4.9 Transportation

Construction and operation of an NGCC plant at the STP site and wind energy projects 

throughout the region would increase the number of vehicles on the roads near these facilities. 

During construction, cars and trucks would deliver workers, materials, and equipment to the 

worksites. Traffic volumes on local roads near these worksites would noticeably increase and 

peak during shift changes resulting in temporary levels of service impacts and delays at 

intersections. Transporting components of wind turbines via roadways could also have a 

noticeable impact on traffic conditions, and this effect is likely to be spread over a large area. 

Pipeline construction and modification to existing natural gas pipeline systems could also have a 

temporary impact. Based on this information, traffic-related transportation impacts during 

construction could range from SMALL to MODERATE depending on the location of the wind 

energy sites, road capacities, and traffic volumes.

Traffic volumes on local roads near construction sites after the installation of the NGCC and 

wind turbines would be noticeably reduced. Given the small number of workers needed to 
Environmental Impacts of Alternatives

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operate the energy projects in this combination alternative, the levels of service impacts on local 

roads during shift changes would be SMALL. In addition, wind energy project operation workers 

would be spread across the service region, and any traffic-related transportation effects from the 

energy efficiency alternative would also be widely distributed. Therefore, overall transportation 

impacts for this combination alternative during operations would be SMALL.

8.4.10 Aesthetics

The analysis of aesthetic impacts focuses on the degree of contrast between the surrounding 

landscape and the visibility of the NGCC plant and wind energy projects. In general, aesthetic 

changes would be limited to the immediate vicinity of the STP site and wind energy projects.

Aesthetic impacts from the NGCC plant component of the combination alternative would be 

essentially the same as those described for the NGCC alternative in Section 8.2.10, except 

there would be one unit rather than four units. During construction, all of the clearing and 

excavation would occur on the STP site. These activities may be visible from offsite roads, 

particularly FM 521. Since the STP site already appears industrial, construction of the NGCC 

power plant would appear similar to onsite activities during refueling outages. Power plant 

infrastructure would be smaller and less noticeable than STP containment and turbine buildings. 

Noise during plant operations would be limited to industrial processes and communications. 

Pipelines delivering natural gas fuel could be audible off site near gas compressor stations. In 

general, aesthetic changes due to the construction and operation of the single-unit NGCC would 

be limited to the immediate vicinity of the STP site and would be SMALL.

The wind energy projects would have the greatest visual impact. Approximately 3,877 wind 

turbines at over 300 ft (100 m) tall would be spread across multiple land-based sites covering 

462,900 ac (187,300 ha). The turbines would dominate the view and would likely become the 

major focus of attention. Offshore wind projects would also be visible because of the height and 

size of the wind turbine generators (MMS 2007). Depending on their location, the aesthetic 

impacts from the construction and operation of the wind energy projects would be MODERATE 

to LARGE.

Impacts from the Energy Conservation and Efficiency Program would be SMALL because it 

would not require any visible changes to existing infrastructure. 

8.4.11 Historic and Archaeological Resources

The same considerations, discussed in Section 8.2.11, for the impact of the construction of a 

four-unit NGCC plant on historic and archaeological resources apply to the construction 

activities that would occur on the STP site for a new one-unit NGCC plant. As described in 

Section 2.2.10, much of the STP site has been previously disturbed by the construction of STP, 

Units 1 and 2. In addition, in preparation for the COL application for Units 3 and 4, STPNOC 

conducted a cultural resources assessment of the STP site. STPNOC reviewed existing 

information for the STP site and the area within a 10-mi (16-km) radius. STPNOC concluded 

that any cultural resource sites that may have existed on site would no longer retain their 

integrity because the area was heavily disturbed during the construction of Units 1 and 2 

(STPNOC 2010b). In December 2006, STPNOC reported these findings to the SHPO at the 

Texas Historical Commission. The SHPO concurred, in January 2007, that there would be no 

impacts to historic properties (STPNOC 2006; THC 2007).

There is a low potential for cultural resources to be located in previously undisturbed portions of 

the STP site. However, if the NGCC unit was to be sited within undisturbed areas or within 

areas of known cultural sensitivity (historic grave site located on the property and described in 
Environmental Impacts of Alternatives

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Section 2.2.10), these areas would need to be surveyed by a professional archaeologist to 

identify and develop possible mitigation measures to address any adverse effects from project 

activities. NRC assumes the plant operator would follow similar procedures to those described 

in the final EIS for STP, Units 3 and 4 (NRC 2011), should the plant operator discover any 

historic or cultural resources during ground-disturbing activities associated with building the new 

units.

Studies would be needed for all areas of potential disturbance at the proposed plant site, wind 

project locations, and along associated corridors where new construction would occur (e.g., the 

new 2-mi pipeline, roads, transmission corridors, rail lines, or other ROWs). Any affected areas 

would need to be surveyed to identify and record historic and archaeological resources, identify 

cultural resources (e.g., traditional cultural properties), and develop possible mitigation 

measures to address any adverse effects from ground-disturbing activities. In most cases, 

long-linear projects (e.g., pipelines) can be sited to avoid areas of greatest sensitivity.

Construction of wind energy projects could affect cultural resource because areas 

approximately 15 to 25 ft (4.6 to 6 m) in diameter would be excavated. Wind turbines can likely 

be sited to avoid sensitive areas because the disturbed area is a small portion of the total 

amount of area required. In addition, wind turbines within the viewshed of traditional cultural 

properties and historic properties could have noticeable impacts to cultural and historic 

resources. Proper siting may be able to mitigate these potential impacts.

The NRC staff determined that the impact on historic and archaeological resources from the 

NGCC portion of the combination alternative would be SMALL for the following reasons:

• NRC (2011) and STPNOC (2010a, 2010b) did not identify any cultural 

resources that could be affected by Units 3 and 4. 

• The SHPO determined that construction for Units 3 and 4 would not affect 

cultural and historic resources. 

• Long-linear projects (e.g., pipelines) can usually be sited to avoid sensitive 

areas. 

• NRC assumes that the plant operator would follow environmental compliance 

procedures for new ground-disturbing activities.

Depending on the resource richness of the site chosen for the wind energy projects, the impacts 

could range between SMALL to MODERATE. Impacts to historic and archaeological resources 

from implementing the Energy Efficiency and Conservation Program would be SMALL and 

would unlikely affect land use or historical or cultural resources elsewhere in Texas. Therefore, 

the overall impacts on historic and archaeological resources from the combination alternative 

could range from SMALL to MODERATE.

8.4.12 Environmental Justice 

The environmental justice impact analysis evaluates the potential for disproportionately high and 

adverse human health and environmental effects on minority and low-income populations that 

could result from the construction and operation of a new NGCC power plant at the STP site, 

wind energy projects, and the Energy Efficiency and Conservation Program. As previously 

discussed in Section 8.1.12, such effects may include human health, biological, cultural, 

economic, or social impacts. Some of these potential effects have been identified in resource 

areas discussed in this SEIS. For example, increased demand for rental housing during plant 

construction could disproportionately affect low-income populations. Minority and low-income 

populations are subsets of the general public living near the STP site and wind energy project 
Environmental Impacts of Alternatives

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sites, and all are exposed to the same hazards generated from constructing and operating an 

NGCC plant and wind energy projects. Section 4.9.7, “Environmental Justice,” presents 

demographic information about minority and low-income populations residing in the vicinity of 

the STP site. 

Potential impacts to minority and low-income populations from the construction and operation of 

a new NGCC plant at the STP site and wind energy projects would mostly consist of 

environmental and socioeconomic effects (e.g., noise, dust, traffic, employment, and housing 

impacts). Noise and dust impacts during construction would be short-term and primarily limited 

to onsite activities. Minority and low-income populations residing along site access roads would 

be directly affected by increased commuter vehicle and truck traffic. However, because of the 

temporary nature of construction, these effects would only occur during certain hours of the day 

and are unlikely to be high and adverse. Increased demand for rental housing during 

construction of the NGCC and wind energy projects could also affect low-income populations 

living near STP and wind energy project sites. Given the proximity of STP to the Houston 

metropolitan area, many construction workers could commute to the STP and wind energy 

project sites, thereby lessening the additional need for rental housing near STP. 

Low-income populations could benefit from weatherization and insulation in an Energy 

Conservation and Efficiency Program. This could have a greater beneficial effect on 

low-income populations than the general population because low-income households generally 

experience greater home energy burdens than the average household. 

Based on this information, and the analysis of human health and environmental impacts 

presented in this SEIS, the combination alternative would not create disproportionately high and 

adverse human health and environmental effects on minority and low-income populations.

8.4.13 Waste Management

During the construction stage for the NGCC plant and wind projects, land clearing and other 

construction activities would generate wastes that could be recycled, disposed of on site, or 

shipped to the offsite waste disposal facility. During the operational stage, spent SCR catalysts, 

which control nitrogen oxide emissions from the NGCC plant, would make up the majority of the 

waste generated by this alternative.

There would be an increase in wastes generated during installation or implementation of energy 

conservation measures, such as appropriate disposal of old appliances, installation of control 

devices, and modifications of buildings. New and existing recycling programs would help to 

minimize the amount of generated waste.

The NRC concludes that overall waste impacts from the combination alternative would be 

SMALL. 

8.4.14 Summary of Impacts of the Combination Alternative

Table 8–5 summarizes the environmental impacts of the combination alternative compared to 

continued operation of the STP.
Environmental Impacts of Alternatives

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Table 8–5. Summary of Environmental Impacts of the Combination Alternative

Compared to Continued Operation of STP, Units 1 and 2

Category Combination Alternative Continued STP Operation

Air quality SMALL to MODERATE SMALL

Surface water SMALL SMALL

Groundwater SMALL SMALL

Aquatic resources SMALL to MODERATE SMALL

Terrestrial resources MODERATE SMALL

Human health SMALL SMALL to MODERATE

Land use SMALL to MODERATE SMALL

Socioeconomics SMALL to MODERATE SMALL

Transportation SMALL to MODERATE SMALL

Aesthetics SMALL to LARGE SMALL

Historic & archaeological SMALL to MODERATE SMALL

Waste management SMALL SMALL

8.5 Purchased Power

Under the purchased power alternative, STPNOC would purchase 2,500 MWe of electricity from 

other power generators. No new generating capacity would be built and operated by STPNOC. 

In its ER, STPNOC assumed that purchased power is a reasonable alternative for the following 

reasons:

• A wholesale electricity market currently exists in the ERCOT region. 

• ERCOT implements rules to anticipate and meet electricity demands and 

promote competition among electricity suppliers. 

• Most of ERCOT’s retail customers can choose a supplier to purchase 

electricity.

If STPNOC purchased electricity, the source of all generated electricity would be within the 

ERCOT region because ERCOT operates wholly within the State of Texas and does not 

interconnect with neighboring reliability regions for the purpose of importing or exporting power 

(STPNOC 2010a). In 2010, electricity produced within the ERCOT region was dominated by 

coal (40 percent), followed by natural gas (38 percent), nuclear (13 percent), wind (8 percent), 

and other sources (1 percent) (ERCOT 2011a). As of April 2011, new energy projects under 

ERCOT’s review included 36,124 MWe of wind power (58 percent); 12,954 MWe of natural 

gas-fired generation (21 percent); 5,900 MWe of nuclear power (9 percent); 4,075 MWe of 

coal-fired generation (7 percent); 1,454 MWe solar power (2 percent); 150 MWe of 

biomass-fired generation (less than 1 percent); and 1,980 MWe of other resources (3 percent) 

(ERCOT 2011a). Based on current and likely future electric generation, NRC assumed that the 

purchased power would likely come from a mixture of coal, natural gas, wind, and nuclear 

energy.

Because the purchased power would be limited to resources available within the ERCOT 

region, new energy generation facilities may need to be built to supply the electricity. 
Environmental Impacts of Alternatives

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Construction impacts would be similar to those described under the new nuclear, coal, natural 

gas, and wind alternatives described in the previous sections. In addition to the construction 

impacts described in Sections 8.1 through 8.3, there could be additional impacts if new plants 

are built on greenfield sites. For example, impacts to aquatic and terrestrial resources and 

historical and cultural resources are likely to be greater due to land clearing of previously 

undisturbed areas. Additional impacts would also occur from construction of support 

infrastructure, like transmission lines and roads. Furthermore, the community would not be 

familiar with the appearance of a power facility, which would change the region’s aesthetic 

character. Workers skilled in power plant or wind farm operations may not be available near a 

greenfield site.

During operations, impacts from new nuclear, coal-fired, and natural gas-fired plants and wind 

energy projects would be similar to that described under the new nuclear, coal, natural gas, and 

wind alternatives described in the previous sections. Impacts from the operations of existing 

coal- and natural gas-fired plants would likely be greater than the operations of new plants 

because older plants are more likely to be less efficient and without modern emissions controls. 

Air quality impacts from the combination of all sources would likely be greater than license 

renewal because a large portion of the purchased power would likely be from coal- and natural

gas-fired plants.

While purchased power is a reasonable alternative, the potential impacts of constructing and 

operating new power generating facilities is addressed elsewhere in this chapter. In general, 

the impacts would likely be greater than license renewal due to potential new construction and 

because continued operation of older plants could result in higher emissions. Ultimately, the 

impacts would depend on the mix of sources used to supply the 2,500 MWe of electricity. 

Below is a brief summary of the impacts for each resource area. 

8.5.1 Air Quality

New and existing nuclear plants and wind farms would not have noticeable impacts on air 

quality. New and existing natural gas- and coal-fired plants would have noticeable impacts on 

air quality; both natural gas- and coal-fired plants emit higher amounts of nitrogen oxides, sulfur 

oxides, PM, HAPs, carbon monoxide, carbon dioxide, and mercury as compared to STP, Units 1 

and 2. The impacts on air quality would be SMALL to MODERATE.

8.5.2 Surface Water and Groundwater Resources

New and existing nuclear, coal-fired, and natural gas-fired plants and wind energy projects 

would not have noticeable impacts on water resources assuming all energy generating facilities 

operate within their associated water quality and water use permits. The impacts on surface 

water and groundwater resources would be SMALL.

8.5.3 Terrestrial and Aquatic Ecology

New and existing natural gas-fired and nuclear plants would not have noticeable impacts on 

aquatic and terrestrial resources assuming plants are built in areas that avoid sensitive species 

and habitats. New, land-based wind energy projects would not have noticeable impacts on 

aquatic resources assuming projects are built in areas that avoid sensitive species and habitats. 

New wind energy projects would have noticeable impacts on avian and bat communities and 

new offshore wind energy projects could have noticeable impacts on fish, whales, turtles, 

benthic organisms, and other marine life. New and existing coal-fired plants would have 

noticeable impacts on terrestrial communities primarily due to the deposition of ash and other 
Environmental Impacts of Alternatives

8-54

pollutants and because of the extent of terrestrial habitat disturbance associated with coal 

mining. The impacts on terrestrial and aquatic ecology would be SMALL to MODERATE. 

8.5.4 Human Health

New and existing nuclear, coal-fired, and natural gas-fired plants and wind energy projects 

would have SMALL impacts on human health due to the extent of regulations to protect public 

health. 

8.5.5 Land Use

Purchased power from existing power plants would not cause any land use changes. New 

power plants would likely be constructed at existing power plant sites. Purchased power from 

coal- and natural gas-fired plants could have a noticeable impact on land use due to the amount 

of land required for coal mining and gas drilling. New wind energy projects would have a 

noticeable land use impact because of the large amount of land required for wind farms. Land 

use impacts would be SMALL to MODERATE.

8.5.6 Socioeconomics (including transportation and aesthetics)

Purchased power from existing power plants would not have any socioeconomic impact 

because there would be no change in power plant operations or workforce. Construction of new 

electrical power generating facilities could cause noticeable short-term socioeconomic and 

transportation impacts due to the number of construction workers required to build the new 

power plant. Traffic volumes would increase on local roads during shift changes. 

Wind energy projects would have the greatest visual impact; wind turbines would dominate the 

view and would likely become the major focus of attention.

The impacts would be SMALL to LARGE.

8.5.7 Historic and Archaeological Resources

Purchased power from existing power plants would not have any impact on historic and 

archaeological resources. In addition, ground-disturbing maintenance activities during 

operations also have the potential to affect historic and archaeological resources.

Construction of new nuclear, coal-fired, and natural gas-fired plants and wind energy projects 

could affect archaeological and historic resources. Archaeological surveys would need to be 

conducted prior to any excavations at proposed power plant sites. After surveys are completed, 

sensitive resource areas could be avoided or mitigated prior to construction. The overall 

impacts on historic and archaeological resources would be SMALL to MODERATE. 

8.5.8 Environmental Justice

Low-income populations could be disproportionately affected by increased utility bills due to the 

cost of purchased power. However, programs are available to assist low-income families in 

paying for increased electrical costs.

Potential impacts to minority and low-income populations from the construction and operation of 

new power plants would mostly consist of environmental and socioeconomic effects (e.g., noise, 

dust, traffic, employment, and housing impacts). Noise and dust impacts during construction 

would be short-term and primarily limited to onsite activities. Minority and low-income 

populations residing along site access roads would be directly affected by increased commuter 
Environmental Impacts of Alternatives

8-55

vehicle and truck traffic. However, because of the temporary nature of construction, these 

effects would only occur during certain hours of the day and are unlikely to be high and adverse. 

Increased demand for rental housing during construction could also affect low-income 

populations living near the construction site. However, workers could commute to the 

construction site, thereby lessening the need for additional rental housing near the construction 

sites. Based on this information, and the analysis of human health and environmental impacts 

presented in this section, the purchased power alternative could disproportionately affect 

low-income populations, but these effects would not be high and adverse.

8.5.9 Waste Management

New and existing nuclear and natural gas-fired plants and wind energy projects would not have 

noticeable impacts. However, new and continued generation of coal-fired plants would have 

noticeable impacts due to the accumulation of ash and scrubber sludge. The overall impacts on 

waste management would range from SMALL to MODERATE.

8.5.10 Summary of Impacts of the Purchased Power Alternative

Table 8–6 summarizes the environmental impacts of the purchased power alternative compared 

to continued operation of the STP.

Table 8–6. Summary of Environmental Impacts of the Purchased Power Alternative

Compared to Continued Operation of STP, Units 1 and 2

Category Purchased Power Continued STP Operation

Air quality SMALL to MODERATE SMALL

Surface water & groundwater SMALL SMALL

Aquatic & terrestrial resources SMALL to MODERATE SMALL

Human health SMALL SMALL to MODERATE

Land use SMALL to MODERATE SMALL

Socioeconomics (including 

transportation & aesthetics)

SMALL to LARGE SMALL

Historic & archaeological SMALL to MODERATE SMALL

Waste management SMALL to MODERATE SMALL

8.6 Alternatives Considered but Dismissed

Alternatives to license renewal that were considered and eliminated from detailed study are 

presented in this section. These alternatives were eliminated due to technical, resource 

availability, or current commercial limitations. Many of these limitations would continue to exist 

when the current STP licenses expire. NRC evaluated an alternative of wind energy in 

combination with an NGCC plant and energy efficiency and conservation programs in 

Section 8.4. The evaluations of wind technology and energy conservation and efficiency 

appearing in this section are as discrete alternatives.
Environmental Impacts of Alternatives

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8.6.1 Offsite Nuclear-, Gas-, and Coal-Fired Capacity

While nuclear-, gas-, and coal-fired power generating alternatives like those considered in 

Sections 8.1 through 8.3, respectively, could be constructed offsite, the impacts would be 

greater than constructing these facilities and making use of existing infrastructure at the STP 

site. Additional impacts would occur from the construction of new water intake and discharge 

structures, as well as other support infrastructure, including transmission lines and roads that 

are already present on the STP site. Furthermore, the community around STP is already 

familiar with the appearance of a power generating facility, and it is an established part of the 

region’s character. Workers skilled in power plant operations may not be available in other 

locations. However, support infrastructure and skilled power-plant workers may be available 

near existing industrial sites, but remediation may also be necessary in order to make the site 

ready for redevelopment. In short, an existing power plant site would present the best location 

for a new replacement power facility.

8.6.2 Energy Conservation and Energy Efficiency

Though often used interchangeably, energy conservation and energy efficiency are different 

concepts. Energy efficiency means deriving a similar level of services by using less energy 

while energy conservation indicates a reduction in energy consumption. Both fall into a larger 

category known as demand-side management. Demand-side management measures address 

energy end uses—unlike energy supply alternatives discussed in previous sections. 

Demand-side management can include measures that do the following: 

• shift energy consumption to different times of the day to reduce peak loads, 

• interrupt certain large customers during periods of high demand, 

• interrupt certain appliances during high demand periods, 

• replace older, less efficient appliances, lighting, or control systems, and 

• encourage customers to switch from gas to electricity for water heating and 

other similar measures that utilities use to boost sales.

Unlike other alternatives to license renewal, the GEIS notes that conservation is not a discrete 

power-generating source; nonetheless, it represents an option that states and utilities may use 

to reduce their need for power generation capability, so the NRC addressed it in the GEIS 

(NRC 1996).

In 2010, the Public Utility Commission of Texas approved Substantive Rule §25.181, which 

requires all electric transmission and distribution utilities within the ERCOT market, including 

CPS Energy and Austin Energy (two of the owners of STP, Units 1 and 2), to use demand-side 

management to reduce their customers’ energy consumption by a minimum of 20 percent of the 

utility’s annual growth. The rule further requires a minimum of 25 percent reduction in 2012 and 

30 percent in 2013 and beyond.

CPS Energy and Austin Energy implement programs to promote demand-side management. 

These programs include load curtailment incentives during periods of peak demand; rebates 

and financial incentives for commercial, industrial, and residential customers for installation of 

energy-efficient appliances and equipment; and the adoption of updated energy codes for new 

building construction (STPNOC 2010a). Demand-side management programs from other Texas 

utilities would also help offset the 2,500 MWe produced by STP because STPNOC sells power 

produced at STPNOC into the ERCOT interconnection (STPNOC 2010a).
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Because Substantive Rule §25.181 already requires annual 30 percent reductions in energy 

consumption from demand-side management, it is unlikely that additional increases in energy 

efficiency in the State of Texas will have grown enough to offset the loss of 2,500 MWe

produced by STP by the time the licenses expire in 2027 and 2028. Because of this, the NRC 

staff has not evaluated energy conservation and efficiency as a discrete alternative to license 

renewal. NRC evaluated an alternative with energy efficiency and conservation programs in 

combination with an NGCC plant and wind energy in Section 8.4.

8.6.3 Wind Power

Texas has significant wind energy resources and leads the Nation in wind-powered generation

capacity (DOE 2011b). As discussed in Section 8.4, as of June 30, 2011, the installed wind 

capacity in Texas was 10,135 MWe (DOE 2011b). Wind resource areas in the Texas 

Panhandle, along the Gulf coasts south of Galveston and in the mountain passes and ridgetops 

of the Trans-Pecos region, offer some of the greatest wind power potential in the U.S. The 

Roscoe Wind Farm in Texas is the largest wind farm in the world with a total capacity of 

781.5 MWe spread across approximately 100,000 ac (40,470 ha) in four counties near Roscoe 

in central Texas.

Newer wind turbines typically operate at approximately a 36 percent annual capacity factor

(DOE 2008). Wind turbines generally can serve as an intermittent power supply (NPCC 2005). 

Wind power might serve as a means of providing baseload power (a) if it is combined with 

energy storage mechanisms, such as pumped hydroelectric or compressed air energy storage 

(CAES), (b) if many wind farms are interconnected to one another on the transmission grid, as 

described in Section 8.4, or (c) if another readily dispatchable power source is used when wind 

power is unavailable (e.g., hydropower). 

EIA is not projecting any growth in pumped storage capacity through 2035 (EIA 2011a). As 

described below, the potential for new hydroelectric development in Texas is limited. Therefore, 

NRC concludes that the use of pumped storage in combination with wind turbines to generate 

2,500 MWe is unlikely in the ERCOT region or Texas.

A CAES plant is another potential storage mechanism that could potentially serve as means for 

wind to provide baseload power. A CAES plant consists of motor-driven air compressors that 

use low cost off peak electricity to compress air into an underground storage medium. During 

high electricity demand periods, the stored energy is recovered by releasing the compressed air 

through a combustion turbine to generate electricity (NPCC 2009). Only two CAES plants are 

currently in operation. A 290-MWe plant near Bremen, Germany, began operating in 1978, and 

a 110-MWe plant located in McIntosh, Alabama, has been operating since 1991. Both facilities 

use salt caverns (Succar and Williams 2008). A CAES plant requires suitable geology, such as 

an underground cavern for energy storage, which would likely be available in Texas due to the 

presence of salt domes. A 268-MWe CAES plant coupled to a wind farm, the Iowa Stored 

Energy Park, had been proposed for construction near Des Moines, Iowa. The facility would 

have used a porous rock storage reservoir for the compressed air (Succar and Williams 2008). 

However, the project has been cancelled due to geologic concerns (ISEPA 2011). Other pilot, 

demonstration, prototype, and research projects involving CAES have been announced, 

including projects in Texas and throughout the U.S. Norton Energy Storage is proposing to 

construct a CAES plant that would provide up to 2,700 MWe of storage capacity in Norton, Ohio 

(OPSB 2011). Projects such as the Conoco-Phillips and General Compression venture may 

use compressed air storage directly without the combustion of fuel such as natural gas. 

However, NRC is not aware of a CAES project coupled with wind generation that is providing 

baseload power. Therefore, NRC concludes that the use of CAES in combination with wind 

turbines to generate 2,500 MWe in the ERCOT region is unlikely.
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A significant challenge for new wind power facilities is that wind farms can be built more quickly 

than transmission lines. It can take a year to build a wind farm, but 5 years to build the 

transmission lines needed to send power to cities. Moreover, wind power developers are 

reluctant to build where transmission lines do not yet exist, and utilities are equally reluctant to 

install transmission in areas that do not yet have power generators (TSECO 2008). Archer and 

Jacobson (2007) examined whether wind projects interconnected to one another on the 

transmission grid could provide a source of baseload power, as described in Section 8.4. This 

study determined that interconnecting wind farms through the transmission grid increases the 

probability that at least one site experiences sufficient wind to produce electricity. Thus, as 

more sites are added to the transmission grid, the interconnected wind farms provide electricity 

that is comparable to a single wind farm providing near constant deliverable wind power. 

However, due to the amount of new transmission lines required and the cost limitations of 

building new transmission lines, it is unlikely that sufficient transmission lines could be built to 

interconnect sufficient wind projects to provide 2,500 MWe of baseload power (with an installed 

capacity of at least 12,000 MWe). 

Offshore Wind. Wind data suggest there is potential for offshore wind farms along the coast of 

Texas, although project costs likely limit the future potential of large-scale projects (NRC 2011; 

Southern and GIT 2007). Southern Company and the Georgia Institute of Technology (GIT) 

studied the viability of offshore wind turbines in the southeast and determined that offshore 

project costs would run approximately 50 to 100 percent higher than land-based systems. Also, 

based on current prices for wind turbines, the 20-year levelized cost of electricity produced from 

an offshore wind farm would be above the current production costs from existing power 

generation facilities. In addition, the current commercially available offshore wind turbines are 

not built to withstand major hurricanes above a Category 3 or a 1-minute sustained wind speed 

of 124 mph. Additional details on the limitations of offshore wind power as a source of baseload 

power is described in the final EIS for STP, Units 3 and 4 (NRC 2011). 

The National Renewable Energy Laboratory (NREL) issued a report that identified offshore wind 

projects in the southeast (NREL 2010). The report identified the proposed Coastal Point Energy 

Project (also called the Galveston Wind Project) off the Texas coast near Galveston 

(approximately 9 mi from shore), which is anticipated to have a capacity of 300 MWe

(NREL 2010). No other wind energy projects were identified by NREL off the coast of Texas or 

its adjoining State (Louisiana).

Conclusion. Although wind power is an important energy resource in the ERCOT region and 

Texas, NRC concludes that a wind energy facility at or in the vicinity of the STP site or 

elsewhere in the ERCOT region would not currently be a reasonable alternative to license 

renewal. NRC evaluated an alternative of wind energy in combination with an NGCC plant and 

energy efficiency and conservation programs in Section 8.4.

8.6.4 Solar Power

Solar technologies use the sun’s energy to produce electricity at a utility scale. Solar energy 

can be converted to electricity using solar thermal technologies or photovoltaics. Solar thermal 

technologies employ concentrating devices to create temperatures suitable for power 

production. Concentrating thermal technologies are currently less costly than photovoltaics for 

bulk power production.

The ERCOT region receives 3.5 to 7.0 kWh/m2

/day of direct solar radiation (STPNOC 2010a). 

Solar power constituted less than 1 percent of electricity produced in the ERCOT region during 

2010 (ERCOT 2011a). As of April 2011, applications for energy projects under review at 

ERCOT included 1,454 MWe of proposed solar projects (ERCOT 2011a).
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As described in the GEIS, solar power is intermittent (i.e., it does not work at night and cannot 

serve baseload when the sun is not shining), and the efficiency of collectors varies greatly with 

weather conditions. Therefore, solar power by itself would not be able to provide baseload 

power as an alternative to Units 1 and 2. Rather, a solar-powered alternative would require 

energy storage or backup power supply from other sources to potentially supply baseload power 

during periods when the sun is not shining. Potential storage mechanisms include pumped 

storage, CAES, molten salt storage, or thermal storage. As described above in Section 8.6.3 

and in STP, Units 3 and 4, EIS (NRC 2011), storage possibilities in this region of Texas are 

limited. NRC is not aware of any storage facility coupled with solar generation that is providing 

baseload power.

For the term of license renewal, because solar energy is an intermittent resource, and the 

amount of solar capacity required to replace Units 1 and 2 far exceeds existing and planned 

amounts of future solar power generation within ERCOT and exceeds storage potential (if 

CAES or pumped storage were used), NRC does not consider solar energy to be a reasonable 

alternative to license renewal.

8.6.5 Hydroelectric Power

Hydropower constituted less than 1 percent of electricity produced in the ERCOT region during 

2010 (ERCOT 2011a). EIA’s reference case in its Update Annual Energy Outlook 2011 projects 

that U.S. electricity production from hydropower plants will remain essentially stable through 

2035 (EIA 2011a). Idaho National Energy and Environmental Laboratory (1998) estimated that 

1,234 MWe of undeveloped potential hydroelectric resources at 89 sites occur throughout the 

State of Texas. Given that the available hydroelectric potential in the State of Texas constitutes 

less than one-tenth of the generating capacity of STP, the NRC staff did not evaluate 

hydropower as a reasonable alternative to license renewal.

8.6.6 Wave and Ocean Energy

Wave and ocean energy has created considerable interest in recent years. Ocean waves, 

currents, and tides are often predictable and reliable. Ocean currents flow consistently, while 

tides can be predicted months and years in advance with well-known behavior in most coastal 

areas. Most of these technologies are in relatively early stages of development. The potential 

for wave and ocean energy in Texas is limited because the Gulf of Mexico is shallow and 

semi-enclosed (TCPA 2008). Because most technologies are relatively undeveloped (and none 

are developed on the scale of STP), and because the Gulf of Mexico has limited potential for 

wave and ocean energy, the NRC did not consider wave and ocean energy as a reasonable 

alternative to STP license renewal.

8.6.7 Geothermal Power

Hydrothermal resources, reservoirs of steam or hot water that can be used for electrical 

generation, are available primarily in the western states, including Hawaii, Alaska, California, 

Utah, and Nevada (TCPA 2008). This type of geothermal energy has an average capacity 

factor of 90 percent and can be used for baseload power where available. Geothermal systems 

have a relatively small footprint and minimal emissions (MIT 2006). However, Texas does not 

have the sort of readily accessible, high-temperature hydrothermal resource (Virtus 2008).

Lower-temperature geothermal resources (90 °F to 160 °F) occur in the central part of Texas 

and along the Rio Grande. In the technical report (TCPA 2008), Texas Comptroller of Public 

Accounts (TCPA) suggests that such areas could provide low-temperature applications, such as 

space heating. Other uses could also include greenhouse cultivation, aquaculture, crop drying, 
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and milk pasteurization. The potential for hot dry rock geothermal power in Texas is presently 

unknown (Virtus 2008).

Geopressured-geothermal power plants use existing, deep oil and gas wells to access hot fluids 

that have been co-produced from oil and gas exploration, such as geopressured reservoirs of 

hot water and natural gas or hot wastewater from deep oil and gas wells. This technology has 

future potential in Texas because hydrocarbon exploration and production industries have data 

on the thermal characteristics in existing wells and because areas with sufficient geothermal 

energy may exist where deep oil and gas wells exists (TCPA 2008). Current data suggest that 

wells 16,000 ft (4,877 m) or deeper in the ERCOT region contain high-temperature fluid (250 °F 

(121 °C) or greater), and some wells are above 400 °F (204 °C) (STPNOC 2010a). In addition, 

transmission lines are located near many of the existing wells (TCPA 2008).

In 1989, DOE operated a test geopressured-geothermal power plant at Pleasant Bayou, 

approximately 60 mi (97 km) northwest of STP. The 1 MW binary power plant operated for 

6 months and produced approximately 3,500 MWh of electricity (TCPA 2008). GEA (2007) 

estimates that electric power production potential from oil and gas wells in Texas could produce 

400 MWe in the near-term to over 2,000 MWe once the technology is refined and more 

widespread. Even if the oil and gas wells produced 2,000 MWe, this output would not be 

sufficient to make up for the 2,500 MWe produced by STP, Units 1 and 2. Additional capital and 

significant investment is required to develop and operate geopressured-geothermal power 

plants to produce a sufficient amount of baseload power.

As of 2008, no geothermal projects produced electricity on a commercial scale in Texas 

(TCPA 2008), but some potential exists for geopressured-geothermal power plants and 

low-temperature projects at smaller scales. Energy companies, Texas State Energy 

Conservation Office, and Southern Methodist University are currently assessing Texas’s 

potential for various forms of geothermal technology. A significant amount of investment would 

be required for geothermal energy to be used in Texas (TCPA 2008). Given the immature 

status of geothermal technology and the limited resource availability in Texas, the NRC 

concludes that geothermal energy is not a reasonable alternative to STP license renewal.

8.6.8 Municipal Solid Waste

Municipal-solid-waste combustors use three types of technologies—mass burn, modular, and 

refuse-derived fuel. Mass burning is used most frequently in the U.S. and involves little sorting,

shredding, or separation. Consequently, toxic or hazardous components present in the waste 

stream are combusted, and toxic constituents are exhausted to the air or become part of the 

resulting solid wastes. Currently, approximately 86 waste-to-energy plants operate in the U.S. 

These plants have a generating capacity of 2,572 MWe, or an average of 30 MWe per plant 

(Michaels 2010). More than 85 average-sized plants would be necessary to provide the same 

level of output as STP.

Estimates in the GEIS suggest that the overall level of construction impact from a waste-fired 

plant would be approximately the same as that for a coal-fired power plant. Additionally, 

waste-fired plants have the same or greater operational impacts than coal-fired technologies 

(including impacts on the aquatic environment, air, and waste disposal). The initial capital costs 

for municipal solid-waste plants are greater than for comparable steam-turbine technology at 

coal-fired facilities or at wood-waste facilities because of the need for specialized waste 

separation and handling equipment (NRC 1996).

The decision to burn municipal waste to generate energy is driven by the need for an alternative 

to landfills rather than energy considerations. The use of landfills as a waste disposal option is 

likely to increase as energy prices increase; however, it is possible that municipal waste 
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8-61

combustion facilities may become attractive again if there is a need for an alternative to landfills 

or an introduction of other regulatory incentives. 

Given the small average installed size of municipal solid-waste plants and the unfavorable 

regulatory environment, the NRC staff does not consider municipal solid-waste combustion to 

be a reasonable alternative to STP license renewal.

8.6.9 Biomass

Using biomass for energy consists of the direct burning of plant or animal matter, including 

wood waste, mill waste, agricultural residues, and energy crops. Biomass fuel provided less 

than 1 percent of electricity produced in the ERCOT region during 2010 (ERCOT 2011a). As of 

April 2011, applications for energy projects under review at ERCOT included 150 MW of 

proposed biomass-fuel projects (ERCOT 2011a). In Texas, the Red River Army Depot cofires 

biomass with fossil fuels (DOE 2004).

Biomass resources in Texas include crops (e.g., cotton, corn, and some soybeans), forests 

(especially in east Texas), and agricultural wastes (e.g., cattle manure, poultry litter, rice straw, 

peanut shells, cotton gin trash, and corn stover) (TCPA 2008). Houston Advanced Research 

Center estimated that Texas agricultural wastes could potentially produce 418.9 MWe

(HARC 2008).

In NUREG-1437, the NRC staff determined that a wood-burning facility can provide baseload 

power and operate with an average annual capacity factor of around 70 to 80 percent and with 

20 to 25 percent efficiency (NRC 1996). The fuels required are variable and site-specific. A 

significant impediment to the use of wood waste to generate electricity is the high cost of fuel 

delivery and high construction cost per megawatt of generating capacity. The larger woodwaste

power plants typically produce 40 to 50 MWe. Estimates in NUREG-1437 suggest that the 

overall level of construction impacts per megawatt of installed capacity would be approximately 

the same as that for a coal-fired plant, although facilities using wood waste for fuel would be 

built at smaller scales (NRC 1996). Similar to coal-fired plants, wood waste plants require large 

areas for fuel storage and processing and involve the same type of combustion equipment.

One of the largest wood-fired biomass power plants began operations in June 2012 in Sacul, 

Texas (Southern 2012). The 100 MWe wood-fired biomass power plant uses logging residue as 

its main fuel source. It also uses urban wood waste (TCPA 2008). The plant owner, Southern 

Power, estimated that the plant will require approximately 1 million tons of biomass per year, 

which it plans to procure within a 75-mi (121-km) radius of the project site (Southern 2009). 

Nearly 26 similarly sized facilities would be necessary to replace STP, Units 1 and 2.

Because of uncertainties associated with obtaining sufficient wood, wood waste, agricultural 

waste, or other biomass to fuel a baseload power plant, the ecological impacts of large-scale 

timber cutting (e.g., soil erosion and loss of wildlife habitat), and the relatively small size of wood 

generation plants, the NRC staff does not consider biomass fuel to be a reasonable alternative 

to STP license renewal.

8.6.10 Biofuels

Biofuels include biomass that has been refined into a liquid fuel, such as ethanol, or gasified 

(including crops and wood waste). The use of biofuels has increased during the past decade 

(TCPA 2008). However, the biofuels are primarily used in the transportation sector, and limited 

projects have been completed to use biofuels for energy generation.
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In the GEIS, the NRC staff indicated that none of the biofuel technologies progressed to the 

point of being competitive on a large scale or of being reliable enough to replace a baseload 

plant such as STP. After re-evaluating current technologies, the NRC staff finds biofuel-fired 

alternatives as still unable to reliably replace the STP capacity. For this reason, the NRC staff 

does not consider biofuels to be a reasonable alternative to STP license renewal.

8.6.11 Oil-Fired Power

The EIA (2009) projects that oil-fired plants will account for very few of new generation capacity 

constructed in the U.S. during the 2011 to 2028 time period. Furthermore, EIA does not project 

that oil-fired power will account for any significant additions to capacity (EIA 2009).

The variable costs of oil-fired generation are greater than those of nuclear or coal-fired 

operations, and oil-fired generation has greater environmental impacts than natural gas-fired 

generation. In addition, EIA expects future increases in oil prices will make oil-fired generation 

increasingly more expensive (EIA 2009). The high cost of oil has prompted a steady decline in 

its use for electricity generation. Thus, the NRC staff does not consider oil-fired generation as a

reasonable alternative to STP license renewal.

8.6.12 Fuel Cells

Fuel cells oxidize fuels without combustion and its environmental side effects. Power is 

produced electrochemically by passing a hydrogen-rich fuel over an anode and passing air (or 

oxygen) over a cathode and then separating the two by an electrolyte. The only byproducts 

(depending on fuel characteristics) are heat, water, and carbon dioxide. Hydrogen fuel can 

come from a variety of hydrocarbon resources by subjecting them to steam under pressure. 

Natural gas is typically used as the source of hydrogen.

At the present time, fuel cells are not technologically competitive with other alternatives for 

large-scale electricity generation. In addition, fuel cell units are likely to be small (the EIA (2009) 

reference plant is 10 MWe). While it may be possible to use a distributed array of fuel cells to 

provide an alternative to STP, it would be extremely costly to do so. Accordingly, the NRC staff 

does not consider fuel cells to be a reasonable alternative to STP license renewal.

8.6.13 Delayed Retirement

STPNOC is not aware of any of ERCOT’s electric generating plants currently proposed or 

planning for retirement, and additional capacity within the ERCOT region is not expected 

(STPNOC 2010a). Electric generating plants that may be retired by 2028 are likely to be older, 

less efficient, and without modern emissions controls. As a result, delayed retirement is not a 

reasonable alternative to license renewal.

In response to the requirements to reduce levels of sulfur dioxide in Texas as a part of the 

Cross-State Air Pollution Rule, ERCOT analyzed the impact of the reliability of the ERCOT grid 

(ERCOT 2011b). In this analysis, ERCOT noted that several facilities may need to idle during 

portions of the year. ERCOT did not state that any facilities would permanently close. 

Statements from power generation companies, such as Luminant, also suggest that facilities 

may need to remain idle in order to comply with the Cross-State Air Pollution Rule 

(Luminant 2011). The NRC is not aware of any facilities that are currently being proposed for 

permanent closure as a result of the Cross-State Air Pollution Rule.
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8.7 No-Action Alternative

This section examines the environmental effects that would occur if NRC takes no action. No 

action in this case means that NRC denies renewed operating licenses for STP, and the 

licenses expire at the end of the current terms, in 2027 and 2028. If NRC denies the renewed 

operating licenses, the plants will shut down at or before the end of the current licenses. After 

shutdown, plant operators will initiate decommissioning in accordance with 10 CFR 50.82.

The NRC staff notes that the no-action alternative is the only alternative that is considered 

in-depth that does not satisfy the purpose and need for this SEIS because it neither provides 

power generation capacity nor does it meet the needs currently met by STP or the alternatives 

evaluated in Sections 8.1 through 8.5. Assuming that a need currently exists for the power 

generated by STP, the no-action alternative would require the appropriate energy-planning 

decisionmakers to rely on an alternative (or combination of them) to replace the capacity of STP 

or reduce the need for power.

This section addresses only those impacts that arise directly as a result of plant shutdown. The 

environmental impacts from decommissioning and related activities have been addressed in 

several other documents, including the Final Generic Environmental Impact Statement on 

Decommissioning of Nuclear Facilities, NUREG-0586, Supplement 1 (NRC 2002); Chapter 7 of 

the license renewal GEIS (NRC 1996); and Chapter 7 of this SEIS. These analyses either 

directly address or bound the environmental impacts of decommissioning whenever STPNOC 

ceases operating STP. In addition, the environmental impacts from potential replacement 

power alternatives are addressed in Sections 8.1 to 8.5.

The NRC staff notes that, even with renewed operating licenses, STP will eventually shut down, 

and the environmental effects addressed in this section will occur at that time. Since these 

effects have not otherwise been addressed in this SEIS, the impacts will be addressed in this 

section. As with decommissioning effects, the NRC staff expects the shutdown effects to be 

similar whether they occur at the end of the current licenses or at the end of renewed licenses.

8.7.1 Air Quality

When the STP stops operating, there will be a reduction in emissions from activities related to 

plant operation, such as use of diesel generators and employee vehicles. In Chapter 4, the 

NRC staff determined that these emissions would have a SMALL impact on air quality during 

the renewal term; therefore, if emissions decrease, the impact to air quality would also decrease 

and would be SMALL.

8.7.2 Surface Water Resources

The rate of consumptive use of surface water would decrease as STP is shut down and the 

reactor cooling system continues to remove the heat of decay. Wastewater discharges would 

also be reduced considerably. Shutdown would reduce the impacts on surface water use and 

quality and would remain SMALL.

8.7.3 Groundwater Resources

The use of groundwater would diminish as the plant workforce is drawn down and operations 

requiring groundwater cease. Some consumption of groundwater would continue to support the 

operation of service water and fire protection systems and to meet the potable and sanitary 

needs of the reduced workforce prior to decommissioning. Overall impacts would be less than 

during operations and would remain SMALL.
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8.7.4 Aquatic Ecology

If STP were to cease operating, impacts to aquatic ecology would decrease, as the plant would 

withdraw and discharge less water than it does during operations. Therefore, fewer organisms 

would be subject to the impingement, entrainment, and heat shock. Shutdown would reduce 

the impacts to aquatic ecology and would remain SMALL.

8.7.5 Terrestrial Ecology

Terrestrial ecology impacts would remain SMALL. No additional land disturbances on or off site 

would occur.

8.7.6 Human Health

Human health risks would be smaller following plant shutdown. The plant, which is currently 

operating within regulatory limits, would emit less gaseous and liquid radioactive material to the 

environment. In addition, following shutdown, the variety of potential accidents at the plant 

(radiological or industrial) would be reduced to a limited set associated with shutdown events 

and fuel handling and storage. In Chapter 4 of this SEIS, the NRC staff concluded that the 

impacts of continued plant operation on human health would be SMALL. In Chapter 5, the NRC 

staff concluded that the impacts of accidents during operation were SMALL. Therefore, as 

radioactive emissions to the environment decrease, and as likelihood and variety of accidents 

decrease following shutdown, the NRC staff concludes that the risk to human health following 

plant shutdown would be SMALL.

Noise caused by plant operations would cease; therefore, impacts from noise would be SMALL.

8.7.7 Land Use

STP shutdown would not affect onsite land use. Plant structures and other facilities would 

remain in place until decommissioning. Most transmission lines connected to STP would 

remain in service after the plant stops operating. Maintenance of most existing transmission 

lines would continue as before. Impacts on land use from plant shutdown would be SMALL.

8.7.8 Socioeconomics

STP shutdown would have an impact on socioeconomic conditions in the region around STP. 

Should the plant shut down, there would be immediate socioeconomic impact from loss of jobs 

(some, though not all, of the 1,378 employees would begin to leave), and tax payments may be 

reduced. As the majority of STP employees reside in Brazoria and Matagorda, socioeconomic 

impacts from plant shutdown would be concentrated in these counties, with a corresponding 

reduction in purchasing activity and tax contributions to the regional economy. Revenue losses 

from STP operations would directly affect Matagorda County and other local taxing districts and 

communities closest to, and most reliant on, the nuclear plant’s tax revenue. The impact of the 

job loss, however, may not be as noticeable given the amount of time required to decontaminate 

and decommission existing facilities and the proximity of STP to the Houston metropolitan area. 

The socioeconomic impacts of plan shutdown (which may not entirely cease until after 

decommissioning) would, depending on the jurisdiction, range from SMALL to MODERATE. 

8.7.9 Transportation

Traffic volumes on the roads in the vicinity of STP would be reduced after plant shutdown. Most 

of the reduction in traffic volume would be associated with the loss of jobs at the plant. 
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Deliveries to the plant would be reduced until decommissioning. Transportation impacts would 

be SMALL as a result of plant shutdown. 

8.7.10 Aesthetics and Noise

Plant structures and other facilities would remain in place until decommissioning. Therefore, 

aesthetic and noise impacts of plant closure and the termination of operations would be SMALL.

8.7.11 Historic and Archaeological Resources

Impacts from the no-action alternative on historic and archaeological resources would be 

SMALL because no additional land disturbances would occur on or off the STP site. 

8.7.12 Environmental Justice

Impacts to minority and low-income populations would depend on the number of jobs and the 

amount of tax revenues lost by communities in the immediate vicinity of the plant after STP 

ceases operations. Closure of STP would reduce the overall number of jobs (there are currently 

1,378 people employed at the facility) and tax revenue for social services attributed to nuclear 

plant operations. Minority and low-income populations in the vicinity of STP could experience 

some socioeconomic effects from plant shutdown, but these effects would unlikely be high and 

adverse. See Appendix J of NUREG-0586, Supplement 1, Final Generic Environmental Impact 

Statement on Decommissioning of Nuclear Facilities Regarding the Decommissioning of 

Nuclear Power Reactors (NRC 2002), for additional discussion of these impacts.

8.7.13 Waste Management

If the no-action alternative were implemented, the generation of high-level waste would stop, 

and generation of low-level and mixed waste would decrease. Impacts from implementation of 

the no-action alternative are expected to be SMALL.

8.7.14 Summary of Impacts of No-Action Alternative

Table 8–7 provides a summary of the environmental impacts of the no-action alternative 

compared to continued operation of STP.
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Table 8–7. Summary of Environmental Impacts of the No-Action 

Alternative Compared to Continued Operation of STP, Units 1 and 2

Category No-action Alternative Continued STP Operation

Air quality SMALL SMALL

Surface water SMALL SMALL

Groundwater SMALL SMALL

Aquatic resources SMALL SMALL

Terrestrial resources SMALL SMALL

Human health SMALL SMALL to MODERATE

Land use SMALL SMALL

Socioeconomics SMALL to MODERATE SMALL

Transportation SMALL SMALL

Aesthetics SMALL SMALL

Historic & archaeological SMALL SMALL

Waste management SMALL SMALL

8.8 Alternatives Summary

In this chapter, the NRC staff considered the following alternatives to STP license renewal: new 

nuclear generation; NGCC generation; supercritical coal-fired generation; a combination 

alternative of natural gas, wind, and energy efficiency and conservation; and a purchased-power 

alternative. No action by NRC and its effects were also considered. The impacts for STP 

license renewal and for all alternatives to STP license renewal are summarized in Table 8–8. 

In conclusion, the environmentally preferred alternative is the license renewal of STP. All other 

alternatives capable of meeting the needs currently served by STP entail potentially greater 

impacts than the proposed action of license renewal of STP. In order to make up the lost 

generation if license renewal is denied, the no-action alternative necessitates the 

implementation of one or a combination of alternatives, all of which have greater impacts than 

the proposed action. Hence, the NRC staff concludes that the no-action alternative will have 

environmental impacts greater than or equal to the proposed license renewal action.
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Table 8–8. Summary of Environmental Impacts of Proposed Action and Alternatives

Alternative

Impact Area

Air QualityGroundwater and Surface waterAquatic and Terrestrial ResourcesHuman HealthLand Use

omics Socioecon

(including 

 & Transportation

Aesthetics)

& Archaeological 

Historic Resources

License renewal SMALL SMALL SMALL SMALL to 

MODERATE SMALL SMALL SMALL 

New nuclear at STP 

site SMALL SMALL SMALL SMALL SMALL SMALL to LARGE SMALL 

NGCC at the STP 

site

SMALL to 

MODERATE SMALL SMALL SMALL SMALL to MODERATE

SMALL to 

MODERATE SMALL 

Supercritical coal at 

STP site MODERATE SMALL SMALL to MODERATE SMALL MODERATE SMALL to LARGE SMALL 

Combination of 

alternatives

SMALL to 

MODERATE SMALL SMALL to MODERATE SMALL SMALL to MODERATE

SMALL to 

LARGE

SMALL 

MODER

Purchased power SMALL to

MODERATE SMALL SMALL to MODERATE SMALL SMALL to MODERATE

SMALL to

LARGE

SMALL 

MODER

No-action alternative SMALL SMALL SMALL SMALL SMALL SMALL to 

MODERATE SMALL 
Environmental Impacts of Alternatives

8-68

8.9 References

10 CFR Part 51. Code of Federal Regulations, Title 10, Energy, Part 51, “Environmental 

protection regulations for domestic licensing and related regulatory functions.”

65 FR 79825. U.S. Environmental Protection Agency. Regulatory finding on the emissions of 

hazardous air pollutants from electric utility steam generating units. Federal Register

65(245): 79825–79831. December 20, 2000.

Archer CL, Jacobson MZ. 2007. Supplying baseload power and reducing transmission 

requirements by interconnecting wind farms. Journal of Applied Meteorology and 

Climatology 46: 1701–1717.

[DOE] U.S. Department of Energy. 2004. Biomass Cofiring in Coal-Fired Boilers. 

Washington, DC: Federal Energy Management Program/DOE. DOE/EE-0288. Available at 

<http://www1.eere.energy.gov/femp/pdfs/fta_biomass_cofiring.pdf> (accessed 

21 November 2011).

[DOE] U.S. Department of Energy. 2007. Cost and Performance Baseline for Fossil Energy 

Plants. DOE/NETL-2007/1281. Volume 1. May 2007.

[DOE] U.S. Department of Energy. 2008. 20% Wind Energy by 2030: Increasing Wind 

Energy’s Contribution to U.S. Electricity Supply. Washington, DC: DOE. 

DOE/GO-102008-2567. ADAMS No. ML100700550.

[DOE] U.S. Department of Energy. 2011a. “Innovative Texas Clean Coal Project Takes Major 

Step Forward as DOE Issues Record of Decision.” September 27, 2011. Available at 

<http://www.fossil.energy.gov/news/techlines/2011/11053-Texas_Clean_Coal_Project_Moves_

For.html> (accessed 21 November 2011).

[DOE] U.S. Department of Energy. 2011b. “Wind Powering America: U.S. Installed Wind 

Capacity.” June 30, 2011. Available at 

<http://www.windpoweringamerica.gov/wind_installed_capacity.asp> (accessed 

20 October 2011).

[EIA] Energy Information Administration. 2009. Annual Energy Outlook 2009 With Projections 

to 2030. Washington, DC: EIA. DOE/EIA 0383(2009). Available at 

<http://www.eia.doe.gov/oiaf/archive/aeo09/pdf/0383(2009).pdf> (accessed 

17 November 2011).

[EIA] Energy Information Administration. 2011a. Annual Energy Outlook for 2011 with 

Projections to 2035. Washington, DC: DOE/EIA. DOE/EIA-0383(2011). April 11, 2011. 

Available at <http://www.eia.gov/forecasts/aeo/index.cfm> (accessed 16 August 2011).

[EIA] Energy Information Administration. 2011b. Assumptions to the Annual Energy Outlook 

2011. Washington, DC: DOE/EIA. July 2011.

[EPA] U.S. Environmental Protection Agency. 1998. Compilation of Air Pollutant Emission 

Factors. Washington, DC: EPA. Volume 1, Section 1.1. 

[EPA] U.S. Environmental Protection Agency. 2008. New Source Review (NSR). ADAMS 

No. ML083450073.

[EPA] U.S. Environmental Protection Agency. 2011a. “Clean Energy: eGRID.” Available at 

<http://www.epa.gov/cleanenergy/energy-resources/egrid/index.html> (accessed 

17 October 2011).
Environmental Impacts of Alternatives

8-69

[EPA] U.S. Environmental Protection Agency. 2011b. “Green Book: Currently Designated 

Nonattainment Areas for All Criteria Pollutants.” August 30, 2011. Available at 

<http://epa.gov/oaqps001/greenbk/ancl.html> (accessed 17 November 2011).

[EPA] U.S. Environmental Protection Agency. 2011c. “New Source Review.” July 22, 2011. 

Available at <http://www.epa.gov/nsr/> (accessed 17 November 2011).

[ERCOT] Electric Reliability Council of Texas. 2011a. “ERCOT Quick Facts.” Available at 

<http://www.ercot.com/about/profile/> (accessed 18 August 2011).

[ERCOT] Electric Reliability Council of Texas. 2011b. “Impacts of the Cross-State Air Pollution 

Rule on the ERCOT System.” September 1, 2011. Available at: 

<http://www.ercot.com/content/news/presentations/2011/ERCOT_CSAPR_Study.pdf> 

(accessed 17 November 2011).

[Exelon] Exelon Generation Company, LLC. 2011. Operating License Renewal Stage—

Limerick Generating Station, Units 1 and 2. 

[GE] General Electric. 2011. “Gas Turbine and Combined Cycle Products.” Available at 

<http://www.ge-energy.com/products_and_services/index.jsp> (accessed 17 October 2011).

[GEA]. Geothermal Energy Association 2007. An Assessment of Geothermal Resource 

Development Needs in the Western United States. Washington, DC: GEA. January 2007. 

Available at <http://www.geo-energy.org/reports/States%20Guide.pdf> (accessed 

12 October 2011).

[HARC] Houston Advanced Research Center. 2008. Combined Heat and Power Potential 

using Texas Agricultural Wastes. The Woodlands, Texas: HARC. January 2008. Available at 

<http://www.seco.cpa.state.tx.us/zzz_re/re_biomass_chp-report2008.pdf> (accessed 

19 October 2011).

[ISEPA] Iowa Stored Energy Plant Agency. 2011. “Iowa Stored Energy Park Project 

Terminated.” July 28, 2011. Available at 

<http://www.isepa.com/ISEP%20Press%20Release.pdf> (accessed 16 November 2011).

Luminant. 2011. “Luminant Announces Facility Closures, Job Reductions in Response to EPA 

Rule; Company Forced to Take Difficult Steps; Files Suit to Protect Jobs, Reliability.” Available 

at <http://www.luminant.com/news/spotlight/detail.aspx?FtID=23> (accessed 

16 November 2011).

Michaels T. 2010. The 2010 ERC [Energy Recovery Council] Directory of Waste-to-Energy 

Plants. Washington, DC: ERC (formerly Integrated Waste Services Association). 

December 2010. Available at <http://www.wte.org/userfiles/file/ERC_2010_Directory.pdf> 

(accessed 30 November 2011).

[MIT]. Massachusetts Institute of Technology. 2006. “The Future of Geothermal Energy: 

Impact of Enhanced Geothermal Systems (EGS) on the United States in the 21st Century: An 

Assessment by an MIT-Led Interdisciplinary Panel.” Available at 

<http://geothermal.inel.gov/publications/future_of_geothermal_energy.pdf> (accessed 

30 November 2011).

[MMS]. U.S. Department of the Interior, Minerals Management Service. 2007. Programmatic 

EIS for Alternative Energy Development and Production and Alternate Uses of facilities on the 

Outer Continental Shelf. Washington, DC: MMS. Report MMS 2007-046.

[NETL] National Energy Technology Laboratory. 2007. Cost and Performance Baseline for 

Fossil Energy Plants, Volume 1: Bituminous Coal and Natural Gas to Electricity. 

Washington, DC: DOE/NETL. DOE/NETL-2007/1281. ADAMS No. ML100640755.
Environmental Impacts of Alternatives

8-70

[NRC] U.S. Nuclear Regulatory Commission. 1996. Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants. Washington, DC: NRC. NUREG-1437. May 1996. 

ADAMS Nos. ML040690705 and ML040690738.

[NRC] U.S. Nuclear Regulatory Commission. 1999. Section 6.3–Transportation, Table 9.1, 

Summary of findings on NEPA issues for license renewal of nuclear power plants. In: Generic 

Environmental Impact Statement for License Renewal of Nuclear Plants. Washington, DC: 

NRC. NUREG-1437, Volume 1, Addendum 1. August 1999. ADAMS No. ML04069720.

[NRC] U.S. Nuclear Regulatory Commission. 2002. Final Generic Environmental Impact 

Statement on Decommissioning of Nuclear Facilities Regarding the Decommissioning of 

Nuclear Power Reactors. Washington, DC: NRC. NUREG-0586, Supplement 1. 

November 2002. ADAMS Nos. ML023470304 and ML023500295.

[NRC] U.S. Nuclear Regulatory Commission. 2008. Generic Environmental Impact Statement 

for License Renewal of Nuclear Power Plants: Regarding Shearon Harris Nuclear Power Plant, 

Unit 1. Washington, DC: NRC. NUREG-1437, Supplement 33.

[NRC] U.S. Nuclear Regulatory Commission. 2011. Environmental Impact Statement for the 

Combined Licenses (COLs) for South Texas Project Electric Generating Station, Units 3 and 4. 

Washington, DC: NRC. NUREG-1937. February 2011. ADAMS No. ML11049A000.

[NPCC]. Northwest Power and Conservation Council. 2005. The Fifth Northwest Electric 

Power and Conservation Plan, Volume 3. Portland, OR. Available at 

<http://www.nwcouncil.org/energy/powerplan/5/Volume3.pdf> (accessed 30 November 2011).

[NPCC]. Northwest Power and Conservation Council. 2009. Draft Northwest 6th Power Plan. 

Portland, OR. Available at <http://www.nwppc.org/energy/powerplan/6/default.htm> (accessed 

30 November 2011).

[NREL]. National Renewable Energy Laboratory. 2009. Land-Use Requirements of Modern 

Wind Power Plants in the United States. Golden, CP: NREL. Technical 

Report NREL/TP-6A2-45834. August 2009.

[NREL]. National Renewable Energy Laboratory. 2010. Large-Scale Offshore Wind Power in 

the United States; Assessment of Opportunities and Barriers. Golden, CO: NREL. Technical 

Report NREL/TP-500-40745.

[OMB] U.S. Office of Management and Budget. 2007. Detailed Information on the Low Income 

Home Energy Assistance Program Assessment. ADAMS No. ML082880730.

[OPSB] Ohio Power and Siting Board. 2011. “99-1626-EL-BGN: Norton Compressed Air 

Energy Storage, Summit County.” Available at 

<http://www.opsb.ohio.gov/opsb/index.cfm/cases/99-1626-el-bgn-norton-energy-storagecompressed-air-energy-storage/> (accessed 30 November 2011).

[Southern] Southern Company. 2009. Southern Company Breaks Ground on Biomass Plant. 

Atlanta, GA: Southern Company. November 10, 2009. ADAMS No. ML100700543.

[Southern] Southern Company. 2012. “Southern Company Highlights.” Available at 

http://www.southerncompany.com/smart_energy/smart_power_highlights.html (accessed 5 

September 2012).

[Southern and GIT] Southern Company and Georgia Institute of Technology. 2007. Southern 

Winds: Summary Project Report 2007, A Study of Wind Power Generation Potential off the 

Georgia Coast. Atlanta, GA: GIT. Available at 

<http://www.energy.gatech.edu/research/Summary-Southern-Winds.pdf> (accessed 

28 November 2011).
Environmental Impacts of Alternatives

8-71

[STPNOC] South Texas Project Nuclear Operating Company. 2006. Letter from SL Dannhardt, 

STPNOC, to B Martin, THC. Subject: South Texas Project, Units 3 and 4. December 12, 2006. 

ADAMS No. ML092100145.

[STPNOC] South Texas Project Nuclear Operating Company. 2010a. Operating License 

Renewal Stage South Texas Project, Units 1 and 2. September 2010. ADAMS 

No. ML103010257. 

[STPNOC] South Texas Project Nuclear Operating Company. 2010b. South Texas Project, 

Units 3 and 4, Combined License Application. Bay City, TX: STPNOC. Part 3, “Environmental 

Report,” Revision 4. ADAMS No. ML102860592.

Succar S, Williams RH. 2008. Compressed Air Energy Storage: Theory, Resources, and 

Applications for Wind Power. Princeton, NJ: Princeton University Energy Systems Analysis 

Group. Available at <http://www.princeton.edu/~ssuccar/caesReport.html> (accessed 

17 October 2011).

[TCEQ] Texas Commission on Environmental Quality. 2005. TPDES Permit 

No. WQ0001908000. Austin, TX.

[TCEQ] Texas Commission on Environmental Quality. 2011. “Status of Air Permits and Permit 

Applications.” Available at 

<http://www.tceq.texas.gov/permitting/air/nav/air_status_permits.html> (accessed 

26 October 2011).

[TCPA]. Texas Comptroller of Public Accounts. 2008. The Energy Report 2008. Austin, TX. 

Available at <http://www.window.state.tx.us/specialrpt/energy/> (accessed 17 October 2011).

[THC]. Texas Historical Commission. 2007. Response from WA Martin for FL Oaks, THC, to 

SL Dannhardt, STPNOC. Stamped Reply: “No Historic Properties Affected Project May 

Proceed.” January 19, 2007. ADAMS No. ML092100145.

[TSECO]. Texas State Energy Conservation Office. 2008. Wind Energy Transmission. 

Austin, TX. ADAMS No. ML100700550.

[TWDB] Texas Water Development Board. 2007. State Water Plan—Water for Texas 2007. 

Austin, TX: TWDB. Document No. GP-8-1.

[Virtus] Virtus Energy. 2008. Texas Renewable Energy Assessment: Geothermal. Austin, TX. 

Available at <http://www.vera.com/re_b_psdoc_07.htm.> (accessed 17 October 2011).

9-1 

9.0 CONCLUSION

This supplemental environmental impact statement (SEIS) contains the environmental review of 

STP Nuclear Operating Company’s (STPNOC’s) application for renewed operating licenses for 

South Texas Project, Units 1 and 2 (STP) as required by Title 10 of the U.S. Code of Federal 

Regulations (CFR) Part 51 (10 CFR Part 51), the U.S. Nuclear Regulatory Commission’s 

(NRC’s) regulations that implement the National Environmental Policy Act (NEPA). This chapter 

presents conclusions and recommendations from the site-specific environmental review of STP 

and summarizes site-specific environmental issues of license renewal that the NRC staff (staff) 

identified during the review. Section 9.1 summarizes the environmental impacts of license 

renewal; Section 9.2 presents a comparison of the environmental impacts of license renewal 

and energy alternatives; Section 9.3 discusses unavoidable impacts of license renewal, energy 

alternatives, and resource commitments; and Section 9.4 presents conclusions and staff

recommendations.

9.1 Environmental Impacts of License Renewal

Based on the staff’s review of site-specific environmental impacts of license renewal presented 

in this SEIS, the staff concludes that issuing renewed licenses would have mostly SMALL 

impacts. The site-specific review included applicable Category 2 issues and uncategorized 

issues. The staff considered mitigation measures for each Category 2 issue, as applicable. 

The staff concluded that no additional mitigation measure is warranted. 

Additionally, the staff independently reviewed STPNOC’s SAMA. The staff agrees with 

STPNOC’s conclusion that none of the candidate SAMAs are potentially cost-beneficial. 

The staff also considered cumulative impacts of past, present, and reasonably foreseeable 

future actions, regardless of what agency (Federal or non-Federal) or person undertakes them. 

The staff concluded in Section 4.12 that cumulative impacts would be SMALL to MODERATE 

depending on the resource area. However, except for the electromagnetic fields-acute effects, 

the incremental contribution from STP during the period of extended operation would be 

SMALL. 

9.2 Comparison of Alternatives

In the conclusion to Chapter 8, the staff considered the following alternatives to STP license 

renewal: 

• new nuclear generation, 

• natural gas-fired combined-cycle generation (NGCC), 

• supercritical coal-fired generation, 

• combination alternative (the combination includes 640 MWe supplied by one 

NGCC unit; 1,620 MWe supplied by wind energy projects; and 300 MWe of 

energy conservation and efficiency, also known as demand-side 

management), and 

• purchased power. 

In addition, the staff also considered many other alternatives that were subsequently dismissed 

for reasons of technical, resource availability, or commercial limitations.
Conclusion

9-2 

As summarized in Table 8–7, the staff concluded that the alternatives of supercritical coal at 

STP, purchased power, or combination alternative would have environmental impacts ranging 

from SMALL to LARGE. The alternatives of new nuclear at STP, NGCC at STP, and the 

no-action alternative would have impacts ranging from SMALL to MODERATE. In comparison 

to other alternatives, the STP license renewal alternative would have mostly SMALL impacts in 

all areas of the environmental analysis. Based on the staff’s independent review, the staff 

concluded that the STP license renewal is the environmentally preferred alternative. 

9.3 Resource Commitments

9.3.1 Unavoidable Adverse Environmental Impacts

Unavoidable adverse environmental impacts are impacts that would occur after implementation 

of all workable mitigation measures. Carrying out any of the energy alternatives considered in 

this SEIS, including the proposed action, would result in some unavoidable adverse 

environmental impacts.

Minor unavoidable adverse impacts on air quality would occur due to emission and release of 

various chemical and radiological constituents from power plant operations. Nonradiological 

emissions resulting from power plant operations are expected to comply with U.S. 

Environmental Protection Agency (EPA) emissions standards, though the alternative of 

operating a fossil-fueled power plant in some areas may worsen existing attainment issues. 

Chemical and radiological emissions would not exceed the national emission standards for 

hazardous air pollutants.

During nuclear power plant operations, workers and members of the public would face 

unavoidable exposure to radiation and hazardous and toxic chemicals. Workers would be 

exposed to radiation and chemicals associated with routine plant operations and the handling of 

nuclear fuel and waste material. Workers would have higher levels of exposure than members 

of the public, but doses would be administratively controlled and would not exceed standards or 

administrative control limits. In comparison, the alternatives involving the construction and 

operation of a non-nuclear power generating facility would also result in unavoidable exposure 

to hazardous and toxic chemicals to workers and the public.

The generation of spent nuclear fuel and waste material, including low-level radioactive waste, 

hazardous waste, and nonhazardous waste would be unavoidable. Hazardous and 

nonhazardous wastes would be generated at non-nuclear power generating facilities. Wastes 

generated during plant operations would be collected, stored, and shipped for suitable 

treatment, recycling, or disposal in accordance with applicable Federal and state regulations. 

Due to the costs of handling these materials, power plant operators would be expected to carry 

out all activities and optimize all operations in a way that generates the smallest amount of 

waste possible.

9.3.2 Short-Term Versus Long-Term Productivity

The operation of power generating facilities would result in short-term uses of the environment, 

as described in Chapters 4, 5, 6, 7, and 8. “Short-term” is the period of time that continued 

power generating activities take place.

Power plant operations require short-term use of the environment and commitment of resources 

and commit certain resources (e.g., land and energy), indefinitely or permanently. Certain 

short-term resource commitments are substantially greater under most energy alternatives, 

including license renewal, than under the no-action alternative because of the continued 
Conclusion

9-3 

generation of electrical power and the continued use of generating sites and associated 

infrastructure. During operations, all energy alternatives entail similar relationships between 

local short-term uses of the environment and the maintenance and enhancement of long-term 

productivity.

Air emissions from power plant operations introduce small amounts of radiological and 

nonradiological constituents to the region around the plant site. Over time, these emissions 

would result in increased concentrations and exposure, but they are not expected to impact air 

quality or radiation exposure to the extent that public health and long-term productivity of the 

environment would be impaired.

Continued employment, expenditures, and tax revenues generated during power plant 

operations directly benefit local, regional, and state economies over the short term. Local 

governments investing project-generated tax revenues into infrastructure and other required 

services could enhance economic productivity over the long term.

The management and disposal of spent nuclear fuel, low-level radioactive waste, hazardous 

waste, and nonhazardous waste requires an increase in energy and consumes space at 

treatment, storage, or disposal facilities. Regardless of the location, the use of land to meet 

waste disposal needs would reduce the long-term productivity of the land.

Power plant facilities are committed to electricity production over the short term. After 

decommissioning these facilities and restoring the area, the land could be available for other 

future productive uses.

9.3.3 Irreversible and Irretrievable Commitments of Resources

This section describes the irreversible and irretrievable commitment of resources that have 

been noted in this SEIS. Resources are irreversible when primary or secondary impacts limit 

the future options for a resource. An irretrievable commitment refers to the use or consumption 

of resources that are neither renewable nor recoverable for future use. Irreversible and 

irretrievable commitment of resources for electrical power generation include the commitment of 

land, water, energy, raw materials, and other natural and man-made resources required for 

power plant operations. In general, the commitment of capital, energy, labor, and material 

resources are also irreversible.

The implementation of any of the energy alternatives considered in this SEIS would entail the 

irreversible and irretrievable commitment of energy, water, chemicals, and—in some cases—

fossil fuels. These resources would be committed during the license renewal term and over the 

entire life cycle of the power plant, and they would be unrecoverable.

Energy expended would be in the form of fuel for equipment, vehicles, and power plant 

operations and electricity for equipment and facility operations. Electricity and fuel would be 

purchased from offsite commercial sources. Water would be obtained from existing water 

supply systems. These resources are readily available, and the amounts required are not 

expected to deplete available supplies or exceed available system capacities.

9.4 Recommendations

The NRC staff’s recommendation is that the adverse environmental impacts of license renewal 

for STP are not great enough to deny the option of license renewal for energy-planning 

decisionmakers. The NRC staff based this recommendation on the following: 
Conclusion

9-4 

• the analysis and findings in NUREG-1437, Volumes 1 and 2, Generic 

Environmental Impact Statement for License Renewal of Nuclear Plants, 

• the Environmental Report (ER) submitted by STPNOC,

• consultation with Federal, state, and local agencies,

• the NRC’s environmental review, and

• consideration of public comments received during the scoping process and 

the draft SEIS comment period. 
10-1 

10.0 LIST OF PREPARERS

This supplemental environmental impact statement (SEIS) was prepared by members of the 

Office of Nuclear Reactor Regulation (NRR) with assistance from other U.S. Nuclear Regulatory 

Commission (NRC) organizations and contract support from Pacific Northwest National 

Laboratory (PNNL). Table 10–1 lists the NRC staff who contributed to the development of the 

SEIS. PNNL provides contract support for cultural resource, hydrology, and severe accident 

mitigation alternative (SAMA) reviews.

Table 10–1. List of Preparers

Name Affiliation Function or Expertise

NRC

D. Wrona NRR Management oversight

B. Pham NRR Management oversight

M. Wong NRR Management oversight

A. Imboden NRR Management oversight

T. Tran NRR Project management

A. BeBault NRR Socioeconomic, environmental justice, 

land use

S. Klementowicz NRR Human health

K. Folk NRR Hydrology and alternatives

M. Moser NRR Aquatic and marine ecology and 

alternatives

B. Grange NRR Terrestrial ecology and protected species 

and habitats

A. Travers NRR Cultural resource

J. Rikhoff NRR Socioeconomic, environmental justice, and 

land use

E. Larson NRR Cultural resource and socioeconomic

W. Rautzen NRR Air quality and meteorology (climatology)

J. Dozier NRR SAMA

National Laboratory Personnel (a)

S. Short PNNL SAMA

R. Schmitt PNNL SAMA

C. Kincaid PNNL Hydrology

R. Prasad PNNL Hydrology

T. O’Neil PNNL Cultural resource
List of Preparers

10-2 

Name Affiliation Function or Expertise

(a) PNNL is operated by Battelle for the U.S. Department of Energy.
11-1 

11.0 LIST OF AGENCIES, ORGANIZATIONS, AND PERSONS TO 

WHOM COPIES OF THIS SUPPLEMENTAL ENVIRONMENTAL IMPACT 

STATEMENT ARE SENT

Name Affiliation 

D. Klima Advisory Council on Historic Preservation 

O. Sylestine Tribal Nation—Alabama–Coushatta Tribe 

B. Horse Tribal Nation—Kiowa Tribe of Oklahoma 

R. Toahty Tribal Nation—Comanche Nation 

M. Orms U.S. Fish & Wildlife Service 

D. Bernhart National Marine Fisheries Service 

K. Boydston Texas Parks & Wildlife Department 

M. Wolfe State Historic Preservation Officer 

A. Street Tribal Nation—Tonkawa Tribe of Oklahoma 

M. Blount Tribal Nation—Apalachicola Band of Creek Indians 

B. Barcena Jr. Tribal Nation—Lipan Apache Tribe of Texas 

D. Romero Jr. Tribal Nation—Lipan Apache Band of Texas 

J. Mendoza Tribal Nation—Pamaque Clan of Coahuila Y Tejas 

R. Hernandez Tribal Nation—Tap PilamCoahuiltecan Nation 

J. Garza Jr. Tribal Nation—Kickapoo Traditional Council 

J. Loera Tribal Nation—Ysleta del Sur Pueblo 

N. Hudgins Coastal Plains Groundwater Conservation District

L. Gaul Texas Department of State Health Services 

EIS Scoping Participant* Affiliation & Address (or E-mail Address)

N. McDonald Matagorda County Judge

1700 7th Street, Room 301, Bay City, TX 77414

J. Gibean Matagorda County Resident

25000 Hwy 35 South, Palacios, TX 77465

S. Dancer S.T.A.R.E

PO Box 209, Blessing, TX 77419

R. Malachowski McDonalds

PO Box 1110, Bay City, TX 77404

M. Butter Matagorda County Economic Development Corporation

2200 7th Street, Suite 302, Bay City, TX 77414
List of Agencies, Organizations, and Persons to Whom Copies of This Supplemental 

Environmental Impact Statement Are Sent

11-2 

L. Bracken Realtor

2055 Ave F, Bay City, TX 77414

B. Watts Matagorda County EMC

2200 7th St, Bay City, TX 77414

M. B. Johnston Palacios City

PO Box 782, Palacios, TX 77465

A. Acosta Matagorda Advocate

Victoria Matagorda Advocate Newspaper

C. Dunohue WCJC Nuke Program

2919 Ave J, Bay City, TX 77414

M. Crews Matagorda County Resident

2200 Golden Ave, Bay City, TX 77414

C. Corporon South Texas Project Nuclear Operating Company

2608 Wofford Rd, Bay City, TX 77414

K. Hadden SEED Coalition

1303 San Antonio Suite 100, Austin, TX 78701

D. Kile U.S. Congressman Ron Paul

122 W Way Suite 301, Lake Jackson, TX 77566

A. Moore Bay City Public Library

1100 7th Street, Bay City, TX 77414

O. Bludau Matagorda County Economic Development Corporation

obludau@co.matagorda.tx.us

T. Farrar Farrar Financial Group

tfarrar4@gmail.com

C. Thames Bay City Resident

thamesforbaycity@yahoo.com

EIS Filing Section U.S. Environmental Protection Agency

1200 Pennsylvania Ave NW, Washington, D.C. 20004

* requested to be on the mailing list
12-1 

12.0 INDEX

accidents, xiv, 4-46, 4-52, 5-1–5-3, 8-64, 

B-8, F-16, F-28

Advisory Council on Historic 

Preservation (ACHP), 1-6, 4-45, E-1 

aesthetic, 4-47, 8-11, 8-12, 8-23, 8-36, 

8-49, 8-53, 8-65

alternatives, 1-5, 4-54, 4-68, 5-2, 5-3, 6-3–

6-5, 8-1–8-3, 8-10, 8-12, 8-21, 8-30, 8-31, 

8-34, 8-39, 8-46, 8-53, 8-55, 8-56, 8-62, 

8-63, 8-66, 8-67, 9-1–9-3, 10-1, B-8, F-1, 

F-2, F-22, F-23, F-32

archaeological resources, 1-6, 2-76, 2-77, 

3-2, 4-42, 4-74, 4-76, 8-12, 8-13, 8-23, 8-24, 

8-36, 8-37, 8-49, 8-50, 8-54, 8-65, B-8, D-1 

biota, 4-11, 4-15, 4-56, 4-66 8-8, B-2 

boiling water reactor (BWR), F-21

burnup, 2-1, B-10

chronic effects, 1-3, 4-34, 4-41, B-7 

Clean Air Act (CAA), 8-16, 8-17, 8-26, 

8-28–8-30, 8-40, 8-41

closed-cycle cooling, 4-20, 4-26, B-4, B-5 

Coastal Zone Management Act (CZMA), 

1-7, 2-79

cooling system, xviii, 1-4, 1-5, 2-17, 4-11–

4-13, 4-20, 4-21, 4-24, 4-26, 4-54, 4-56, 4-

57, 8-3, 8-4, 8-8, 8-20, 8-32, 8-44, 8-63, 

B-3, B-4, F-7 

core damage frequency, 5-4–5-11, F-1–

F-9, F-11, F-13–F-16, F-20–F-23, F-26–

F-30, F-33

Council on Environmental Quality (CEQ), 

1-3, 4-13, 4-47, 4-78

critical habitat, 2-43, 2-49, 2-52, 2-79, 4-

29, 4-31, 8-9, C-5 

cultural resources, 2-76, 2-77, 2-85, 4-45, 

4-46, 4-74, 4-82, 8-12, 8-13, 8-23, 8-24, 

8-36, 8-37, 8-49, 8-50, 8-53, C-1 

Decommissioning, xiv, 7-1, 7-2, 8-63, 

8-65, 8-70, B-10

design-basis accident, 4-52, 5-1, B-8 

discharges, 2-5, 2-8, 2-9, 2-17, 2-19, 2-20, 

2-47, 2-48, 4-8, 4-9, 4-11, 4-20, 4-24–4-26, 

4-37–4-39, 4-56, 4-66, 8-8, 8-15, 8-19, 8-20, 

8-26, 8-31, 8-32, 8-43, 8-44, 8-63, B-2, B-3, 

C-3 

dose, 2-2, 2-3, 4-37, 4-38, 4-71, 4-72, 4-76, 

5-7, 5-8, 5-10, 6-2, B-6, B-8, F-1, F-6, F-7, 

F-16–F-19, F-21, F-23, F-26–F-28

education, 3-2, 4-41, B-7 

electromagnetic fields, 1-3, 4-27, 4-27, 4-

41, 4-52, 4-72, 9-1, B-5, B-7 

Endangered Species Act (ESA), xiv, 2-47, 

2-48, 2-50, 2-51, 2-53, 2-55, 2-56, 2-58, 4-

28–4-32, 4-81

entrainment, 2-61, 4-12–4-17, 4-12–4-17, 

4-20–4-22, 4-24, 4-26, 4-27, 4-33, 4-66, 8-8, 

8-9, 8-20, 8-32, 8-44, 8-64, B-2, B-3 

essential fish habitat, 2-59, 2-61, 2-84, 4-

21, 4-33, 4-66, 4-81, 4-83, E-9 

Generic Environmental Impact Statement 

(GEIS), xvii, xviii, 1-3–1-7, 2-6, 2-67, 3-1, 

3-2, 4-1, 4-2, 4-5, 4-6, 4-8, 4-11, 4-12, 4-27, 

4-28, 4-34, 4-35, 4-39, 4-41–4-44, 4-54, 4-

55, 4-58, 4-72, 5-1, 5-2, 6-1–6-3, 7-1, 7-2, 

8-1, 8-2, 8-10, 8-14, 8-15, 8-21, 8-22, 8-25, 

8-27, 8-34, 8-35, 8-41, 8-45–8-48, 8-56, 

8-59, 8-60, 8-62, 8-63, B-8, E-7, E-8 

greenhouse gases, 8-6, 8-15, 8-17, 8-30, 

8-41, 8-42

groundwater, 1-5, 2-9, 2-10, 2-12, 2-16, 2-

19–2-23, 2-36, 2-37, 2-65, 3-1, 4-5–4-11, 4-

35–4-37, 4-53–4-56, 4-61, 4-63–4-65, 4-67, 

4-75, 5-2, 8-3, 8-7, 8-8, 8-19, 8-31, 8-32, 

8-44, 8-53, 8-55, 8-63, B-4, B-5, B-8, C-1 

hazardous waste, 2-4, 2-5, 9-2, 9-3, C-3, 

C-4 

heat shock, 4-24, 4-66, 8-9, 8-20, 8-32, 

8-64, B-3 

high-level waste, xviii, 1-4, 6-1, 6-2, 8-14, 

8-65, B-8–B-10
Index

12-2 

impingement, 2-61, 4-12, 4-13, 4-15, 4-16, 

4-18, 4-20, 4-21, 4-24, 4-26, 4-27, 4-33, 4-

66, 8-8, 8-9, 8-20, 8-32, 8-44, 8-64, B-2–B-4 

low-level waste, 2-4, 6-1, 8-14, B-9 

maximum occupational doses, 4-35, B-7 

mitigation, xviii, 1-3–1-5, 4-2, 4-27, 4-35, 4-

40, 4-57, 4-72, 5-2, 7-1, 7-2, 8-12, 8-24, 

8-37, 8-50, 9-1, 9-2, 10-1, E-5, F-1, F-14

mixed waste, 8-14, 8-65, B-9 

National Environmental Policy Act 

(NEPA) , xvii, xviii, 1-1, 1-5, 1-7, 1-8, 2-75, 

2-77, 2-85, 3-3, 4-13, 4-45–4-47, 4-65, 4-79, 

4-81, 4-82, 5-1, 6-2, 6-3, 6-10, 7-2, 8-1, 

8-70, 9-1, B-1, B-9, E-7 

National Marine Fisheries Service 

(NMFS), 1-6, 2-47, 2-79, 2-84, 2-85, 4-28, 

4-80, 4-81, 11-1, D-1–D-4 

National Pollutant Discharge Elimination 

System (NPDES), 4-21, 8-7, 8-19, 8-32, 

B-2, C-1, C-3 

no-action alternative, 4-13, 4-65, 8-2, 

8-63, 8-65, 8-66, 9-2 

nonattainment, 4-60 

once-through cooling, 4-20, 4-26, B-2, B-3 

radon, 4-36, B-8, B-9 

reactor, xvii, xviii, 1-5, 2-1, 2-2, 2-4, 2-6, 2-

13, 2-16, 2-23, 2-47, 3-1, 3-2, 4-38, 4-43, 4-

57, 4-59, 4-71–4-73, 4-76, 5-1–5-3, 5-10, 

6-2, 6-4, 7-1, 8-4, 8-7, 8-11, 8-12, 8-23, 

8-36, 8-63, B-4, B-8, F-16, F-18, F-29

refurbishment, 2-14, 2-48, 2-75, 3-1, 3-2, 

4-34, 4-35, 4-38, 4-42, 4-46, 4-55–4-57, 4-

60, B-1, B-2, B-4–B-8, C-3, F-28

salinity gradients, 4-2, B-1 

scoping, xvii, 1-2, 1-5, 1-6, 4-1, 4-2, 4-5, 4-

12, 4-13, 4-27, 4-35, 4-42, 4-46, 4-55–4-58, 

5-2, 6-2, 7-2, 9-4, E-1–E-4, E-7 

Severe Accident Mitigation Alternatives 

(SAMA), xiv, 5-3, 5-4, 5-8–5-11, 5-13, 9-1, 

10-1, F-1–F-3, F-7, F-8, F-11, F-12, F-14–

F-34, F-37

severe accidents, xiv, 4-52, 5-1–5-3, B-8, 

F-13, F-27–F-29

solid waste, 2-1–2-4, 6-1, 7-2, 8-2, 8-27, 

8-31, 8-60 B-10, C-1 

spent fuel, xviii, 1-4, 2-2, 4-71, 6-1, 6-2, 

B-8–B-10

State Historic Preservation Officer 

(SHPO), 1-6, 2-85, 4-45, 4-46, 4-81, 8-12, 

8-13, 8-23, 8-24, 8-36, 8-37, 8-49, 8-50, E-2 

State Pollutant Discharge Elimination 

System, C-1 

surface water, 2-10, 2-18, 2-21, 2-22, 3-1, 

4-2, 4-3, 4-5, 4-8, 4-9, 4-36, 4-52, 4-53, 4-

55, 4-61–4-63, 4-67, 4-69, 4-75, 8-3, 8-6, 

8-7, 8-18–8-20, 8-31–8-33, 8-43, 8-44, 8-53, 

8-63, B-1, B-4, C-1 

transmission lines, 2-6, 2-8, 2-43, 2-48, 2-

63, 4-2, 4-11, 4-29, 4-34, 4-39–4-42, 4-45, 

4-55, 4-57, 4-67, 4-70, 4-72, 4-74, 8-39, 

8-43, 8-45, 8-46, 8-53, 8-56, 8-58, 8-60, 

8-64, B-6, B-8 

tritium, 2-22–2-24, 4-9–4-11, 4-35–4-37, 4-

63

U.S. Department of Energy (DOE), 4-37, 

4-41, 8-2, 8-3, 8-18, 8-27, 8-39, 8-42, 8-57, 

8-60, 8-61, 8-68, 8-69

U.S. Environmental Protection Agency 

(EPA), 2-1, 2-4–2-6, 2-14, 2-22–2-24, 2-37, 

2-38, 2-65, 2-67, 2-81, 2-88, 2-89, 4-9–4-13, 

4-20, 4-21, 4-24, 4-25, 4-37, 4-38, 4-59, 4-

63, 4-65, 4-71, 4-72, 4-76, 4-78, 4-79, 8-2, 

8-5, 8-16–8-18, 8-26, 8-28–8-30, 8-34, 

8-40–8-42, 8-68, 8-69, 9-2, C-1–C-5 

uranium, 2-1, 2-2, 4-71, 4-72, 6-1, 6-2, 6-4–

6-8, 8-10, 8-21, 8-34, 8-47, B-8–B-10

wastewater, 2-5, 2-9, 2-78, 2-88, 4-2, 4-69, 

8-60, B-2, C-3 

Yucca Mountain project, B-10
APPENDIX A 

COMMENTS RECEIVED ON THE STP ENVIRONMENTAL REVIEW

A-1 

COMMENTS RECEIVED ON THE STP ENVIRONMENTAL REVIEW

A.1 Comments Received During the Scoping Period

The scoping process began on January 31, 2011, with the publication of the U.S. Nuclear 

Regulatory Commission’s (NRC’s) Notice of Intent to conduct scoping in the Federal Register

(76 FR 5410). The scoping process included two public meetings held at the Bay City Civic 

Center in Bay City, Texas, on March 2, 2011. Approximately 60 members of the public attended 

the meetings. After the NRC’s prepared statements pertaining to the license renewal process, 

the meetings were open for public comments. Attendees provided oral statements that were 

recorded and transcribed by a certified court reporter. Any written statements submitted at the 

public meeting are documented in the transcript of the meetings. Transcripts of the two 

meetings are an attachment to the Scoping Meeting Summary, dated May 19, 2011 

(Agencywide Documents Access and Management System (ADAMS) No. ML110770661). In 

addition to the comments received during the public meetings, comments were also received 

electronically and through the mail.

Each commenter was given a unique identifier, so every comment could be traced back to its 

author. Table A–1 identifies the individuals who provided comments applicable to the 

environmental review and the Commenter ID associated with each person’s set of comments. 

The individuals are listed in the order in which they spoke at the public meeting and in numerical

order for the comments received by letters or e-mails. 

Specific comments were categorized and consolidated by topic. Comments with similar specific 

objectives were combined to capture the common essential issues raised by participants. 

Comments fall into one of the following general groups: 

• Specific comments that address environmental issues within the purview of 

the NRC environmental regulations related to license renewal. These 

comments address Category 1 (generic) or Category 2 (site-specific) issues 

identified in NUREG-1437, Generic Environmental Impact Statement for 

License Renewal of Nuclear Plants (GEIS) or issues not addressed in the

GEIS. The comments also address alternatives to license renewal and 

related Federal actions. 

• General comments in support of or opposed to nuclear power or license 

renewal or comments regarding the renewal process, the NRC’s regulations, 

and the regulatory process. 

• Comments that address issues that do not fall within or are specifically 

excluded from the purview of NRC environmental regulations related to 

license renewal. These comments typically address issues such as the need 

for power, emergency preparedness, security, current operational safety 

issues, and safety issues related to operation during the renewal period. 

Table A–1. Individuals Providing Comments During the Scoping Comment Period

Commenter Commenter ID Affiliation (if stated) ADAMS No.

Randy Weber STP 1 State Representative ML110840441

Judge Nate McDonald STP 2 Matagorda County judge and local 

emergency response official ML110840441
Appendix A

A-2 

Commenter Commenter ID Affiliation (if stated) ADAMS No.

Mark Bricker STP 3 Bay City Mayor ML110840441

Ron Paul’s office STP 4 U.S. congressman ML110840441

Ed Halpin STP 5 STP CEO ML110840441

Carolyn Thames STP 6 Bay city council member ML110840441

Don Booth STP 7 Director local 211 Pipefitter union of 3,000 ML110840441

Cheryl Stewart STP 8

Bay City Community Development 

Corporation board member and Bay City 

Historic Commission

ML110840441

David Dunham STP 9 Matagorda County resident ML110840441

Owen Bludau STP 10 Director of Matagorda County Economic 

Development Corporation ML110840441

Kesha Rogers STP 11 Congressional candidate for 22nd 

Congressional District ML110840441

James Lovett STP 12 ML110840441

D. C. Dunham STP 13 Bay City Community Development 

Corporation ML110840441

Willie Rollins STP 14 Matagorda County resident ML110840441

Ian Overton STP 15 LaRouche PAC organizer ML110840441

John Corder STP 16 Brazoria County resident ML110840433

Judge Nate McDonald STP 17 Matagorda County judge ML110840433

Mitch Thames STP 18 Chamber of Commerce, emergency 

response public information officer ML110840433

Tim Powell STP 19 STP Vice President ML110840433

Ken Head STP 20 ML110840433

Mike Bolin STP 21 ML110840433

John Corder STP 22 Brazoria County resident ML110840433

Casey Kile STP 23 Bay City Babe Ruth (local sport 

organization) ML110840433

Robert Singleton STP 24 Austin resident ML110840433

Karen Hadden STP 25 Executive director of SEED Coalition ML110840433

Bobby Head STP 26 Matagorda County resident ML110840433

Tom Kovar STP 27 Bay City resident ML110840433

Vicki Adams STP 28 Superintendent Palacios ISD ML110730188

Eva Esparza STP 29 Austin resident ML110960078

Darby Riley STP 30 San Antonio resident ML110960079

Kamala Platt STP 31 ML110960080

Marion Mlotok STP 32 Austin resident ML110960081

Karen Seal STP 33 Lacoste resident ML110960082
Appendix A

A-3 

Commenter Commenter ID Affiliation (if stated) ADAMS No.

Kassandra Levay STP 34 San Antonio resident ML110960083

Unknown STP 35 ML110960084

T. Burns STP 36 Midland resident ML110960086

Jolly Clark STP 37 ML110960087

Dale Bulla STP 38 ML110960088

William Stout STP 39 ML110960089

C. J. Keudell STP 40 Austin resident ML110960090

Tarek Tonsson STP 41 ML110960091

Carol Geiger STP 42 ML110960092

Veryan and Greg Thompson STP 43 ML110960093

Robert Singleton STP 44 ML110960094

Karen Hadden STP 45 SEED Coalition ML110960095

Alan Apurim STP 46 ML110960096

Brandi Clark Burton STP 47 Austin resident ML110960097

Carol Geiger STP 48 Austin resident ML110960098

Eric Lane STP 49 San Antonio resident ML110960099

Jenna Findley STP 50 ML111010476

Margaret Reed STP 51 Austin resident ML111010477

Scott and Cyndy Reynolds STP 52 ML111010478

Jennifer Meador STP 53 Austin resident ML111010604

Joy Malacara STP 54 Austin resident ML111010479

Melanie and David Winters STP 55 ML111010506

J. R. Rhode STP 56 ML111010507

Christine Fry STP 57 ML111010508

Leona Slodge STP 58 Austin resident ML111010509

Carolyn Campbell STP 59 Austin resident ML111010510

Bryan Dunlap and Todd 

Rinehart STP 60 ML111010517

Peggy Cravens STP 61 Austin resident ML111010518

Shannon Jurak STP 62 Austin resident ML111010519

Thomas Nelms STP 63 ML111010520

T. Nelms STP 64 ML111010521

Peggy Pryor STP 65 Andrews resident ML110960077

Edmund Kelley STP 66 Austin resident ML11105A023

Maria Hogan STP 67 ML11105A020
Appendix A

A-4 

Commenter Commenter ID Affiliation (if stated) ADAMS No.

Randy Weber

STP 1 (letter, 

also captured in 

public meeting 

transcript)

Texas State Representative ML11108A059

Beth Larsen STP 68 Austin resident ML11119A007

Dzan Nguyen STP 69 Austin resident ML11119A008

John Trimble STP 70 Austin resident ML11119A010

Aguilar family STP 71 ML11119A011

Juan Aguilar STP 72 ML11119A012

Douglas McArthur STP 73 Austin resident ML11119A013

Shawn Tracy STP 74 ML11119A014

Kelly Simon STP 75 Austin resident ML11119A015

N/A STP 76 ML11119A016

Judy Moore STP 77 ML11119A017

Cynthia Gebhardt STP 78 ML11119A018

Rory Holcomb STP 79 Austin resident ML11119A019

N/A STP 80 ML11119A020

Comments received during the scoping comment period applicable to this environmental review 

are presented in this section along with the NRC response. The comments that are general or 

outside the scope of the environmental review for South Texas Project (STP) license renewal 

are not included here but can be found in the Scoping Summary Report (ADAMS 

No. ML11153A082). To maintain consistency with the Scoping Summary Report, the unique 

identifier used in that report for each set of comments is retained in this Appendix A.

Applicable scoping comments are grouped in the following categories and presented in the 

following order: 

• alternatives to license renewal of STP, 

• socioeconomic impact of STP, 

• water usage, 

• human health,

• postulated accidents, 

• terrestrial or aquatic ecology, and 

• uranium fuel cycle and waste management. 

A.1.1 Alternatives to License Renewal of STP, Units 1 and 2 

The original sources for the comments in this category (alternatives to license renewal) can be 

found at the back of the Scoping Summary Report and are labeled with the following identifiers: 

12-2, 15-1, 24-3, 25-5, 26-2, 27-2, 27-4, 29-2, 30-1, 31-2, 32-3, 35-2, 36-6, 38-2, 39-3, 40-2, 

43-3, 45-3, 46-3, 47-4, 49-2, 51-2, 52-2, 53-2, 54-3, 55-2, 57-2, 59-2, 60-3, 61 2, 62-2, 69-2, 

73-2, 74-1, 77-2, 79-2, and 80-2. These comments are extracted from the original sources.
Appendix A

A-5 

Comment 12-2: Several nations have nuclear energy policies. These policies are all variations 

on one theme: one, oil is not a dependable source of energy, it can be interrupted at any time 

and it is not feasible to store more than a few months worth of reserve supply; two, nuclear 

energy is the only source of energy, other than wind and solar—which I hope come along in the 

future but at the present have to be considered in the development stage—nuclear energy is the 

only source of energy that can produce large quantities of energy without dumping large 

quantities of carbon dioxide into the atmosphere.

Yes, the natural gas plant is better than the coal plant, and I’m not particularly in favor of a coal 

plant in Matagorda County, but natural gas is contributing to global warming, and we cannot 

afford to build any more of it than we have to.

I’m a strong supporter of nuclear energy; I’m a strong supporter of renewing these. In due 

course, I will be a strong supporter of Units 3 and 4. Thank you.

Comment 15-1: And, I think that it’s probably best, when talking about the environmental 

benefits of nuclear power, to compare it with the environmental problems that other forms of 

power offer. So for example, the amount of energy in one pellet of uranium, about the size of 

my fingernail here, is equivalent in energy to about 30 barrels of oil or 6.15 tons of coal, or 

23 1

/2 tons of dry wood.

When you start going into other examples of energy, such as wind or solar, the amount of return 

gets even worse because the amount of radiant heat coming down from the sun is only about 

200 watts per square meter, and the amount of land area and the cost of building and 

maintaining solar panels or windmills is far, far greater than the actual benefit you get from 

them, not to mention that windmills kill birds by the dozen and solar panels, with their polarized 

lights, kill insects by the countless numbers.

Comment 24-3: Nuclear power was also always intended to be a bridge technology. We’re 

always going to find something better, and what we could do right now instead of re-license 

these is make an investment in renewables which could have, in terms of jobs, just as much of 

an impact as extending the life of this plant or building new units.

The other thing about switching forms of energy is that you can create jobs locally that are going 

to be exclusively locally. Nuclear power, a lot of the jobs that are generated are going to be 

foreign manufacturing jobs. The components for these plants are built off site; they don’t really 

generate that much for your local economy.

There are new and exciting technologies that we could be counting on. For example, there’s an 

Australian company called EnviroMission that’s just about to open a project in Arizona. What it 

is; it’s a tower, just a tower, covered around the base with thick plastic. What it does is it 

captures the heat of the sun; the heated air rises up a chimney and turns a turbine. It’s basically 

the only moving part, so the turbine and then the generators from it.

The cool thing about it is that it continues to generate electricity even at night because the hea[t]

of the ground continues to make this temperature differential, and the air continues up the 

chimney, and the turbines continue to turn.

This is the kind of thing that can be built and provide localized power. In West Texas, for 

example, we could build these things and not have to ship the power across the State. We 

could actually use it to provide energy where it’s built.

Comment 25-5: A big issue is need for power. Right now in the legal case involving Units 3 

and 4, the Atomic Safety and Licensing Board has agreed to hear a contention that is one of 

omission. There was a failure to analyze what alternatives were there in terms of looking at 

energy efficiency. Building codes in particular are going to be saving; they’ve been adopted, 
Appendix A

A-6 

going to be saving some 2,200 megawatts of power in Texas. We need to look at whether the 

power is needed and then we need to look at how else it could be generated.

And, certainly[,] jobs are crucially important in every community. We realize that that’s 

important here. I think it’s time to look at what are the options in terms of transition, what other 

kinds of ways to generate electricity could occur here; I think there are many and to start looking 

at training and what other options exist.

Comment 26-2: Randy Weber was here last week. He’s our State representative. He got over 

in the next room and he said that Texas is growing by 113,000 people a month. Wow. We’re 

outgrowing all the states combined. We’re getting more people into Texas. He says if we keep 

growing the way we are, that by 2015 we’re going to have to have five new nuclear plants, or 

16 coal plants, or 28 gas plants, or 3,000 windmills if the windmills agree to turn 24-7-365. You 

know that’s not going to happen.

Would I like to see all of our power generated totally clean[?] Yes, I would. It’s not realistic, not 

with what we have as today’s knowledge.

Comment 27-2: You have to have electricity and you have to have a lot of it. I wish I could 

afford Austin’s 16 percent. But, you have to have a lot of electricity nowadays because of the 

way the population is, and if you look at the last 40-50 years of power generation, of gas-fired 

plants or coal-fired plants and how hazardous they are to the environment and people, then I 

think you [cannot] help but realize how safe nuclear power is. The Government has been using 

it to power their vehicles in the military for a long time.

Comment 29-2: There are safer alternative technologies that can replace the energy generated 

by these reactors.

Comment 30-1: Well before 2027, we should have outgrown the need for nuclear power with 

clean alternative energy and conservation [and] efficiency ...

Comment 31-2: I urge the denial of the relicensing of the STP. As a San Antonio resident, I 

value my community and know that we are committed to renewables and conservation, much 

better paths to the future on a sustainable planet.

Comment 32-3: We should be investing in solar and wind and dismantling our aging reactors.

Comment 35-2: There are cheaper and renewable ways to get our power, and I would love to 

see Texas lead the way in these fields. Not continue to lead us down a dead end road with 

nuclear power.

Comment 36-6: STP does not displace [carbon dioxide] emissions. Other, truly renewable 

energy sources are much more highly developed now and can replace STP. By scheduled 

renewal, nuclear energy will be totally unnecessary.

Comment 38-2: We need to move toward heavy development of solar and wind regardless of 

the cost[—]they would be so much safer (and most likely cheaper in the long run, considering

[(lacking of or merit of)] all the waste and other negatives of solar).

Comment 39-3: Safer, cleaner alternative ways to generate the same power (in essence[,] to 

boil water) exist today and should be used and funded, just like the Nuclear and Petroleum 

industries have been subsidized by the U.S. Government to the tune of BILLIONS of dollars 

annually.

Comment 40-2: At this point in time, I feel that the U.S. should move away from nuclear and oil 

as primary energy sources. Let’s develop more renewable options.
Appendix A

A-7 

Comment 43-3: Here in Texas, we have a wonderful abundance of sun as well as wind, neither 

depend[e]nt on other countries. We should be making use of these natural resources[,] which 

are safer, reduce use of scarce water, and [cannot] be used as political weapons.

Comment 45-3: Safer, cleaner alternative ways to generate the same power exist today and 

should be used. We should not be subjected to worrying about radioactive contamination—just 

to generate electricity. We should not have to worry about terrorists attacking a radioactive 

energy generation source, and we don’t have these worries with solar, geothermal, natural gas, 

or wind power. These forms of energy generation, combined with energy efficiency and 

ever-improving methods of storage, could easily replace the electricity generated by Units 1 

[and] 2. When these units have been down due to problems or fuel replacement, it did not 

cause problems with the grid or lead to blackouts. We can replace the generation of these units 

with safer, cleaner technologies.

Comment 46-3: For alternative energy sources, and a way to get the USA off foreign oil 

dependence that is costing us both in trade balance and military costs, see the downloadable 

document describing achievable ecological solutions for all these needs:

http://phoenixprojectfoundation.us/uploads/USA Article V SHE Document.pdf

Thank you for your hard work and consideration of these issues. Please be sure to keep me 

informed as this regulatory process proceeds.

Comment 47-4: We have safer and cleaner ways to generate the same power—THAT is where 

our money and attention need to be directed.

Comment 49-2: There are safer, cleaner alternatives to generate the same power that exists 

today, and we should commit the country to use them.

Comment 51-2: Safer, cleaner alternative ways to generate the same power exist today and 

should be used. Studies have found that energy efficiency and renewable energy sources, 

which are abundant in Texas, could replace the power generated by these two old nuclear 

reactors.

Comment 52-2: NOW is the time to make a commitment to safer and renewable energy 

sources.

Comment 53-2: Safer, cleaner alternative ways to generate the same power exist today and 

should be used. Studies have found that energy efficiency and renewable energy sources, 

which are abundant in Texas, could replace the power generated by these two old nuclear 

reactors.

Comment 54-3: There are safer, cleaner alternative ways to generate the same power available 

today, and these should be used instead of nuclear energy.

Comment 55-2: Safer, cleaner alternative ways to generate the same power exist today and 

should be used. Studies have found that energy efficiency and renewable energy sources, 

which are abundant in Texas, could replace the power generated by these two old nuclear 

reactors.

Comment 57-2: I believe there are alternative ways to generate power and support a more 

...[uncertain handwriting].

Comment 59-2: There are safer, cleaner alternative ways to generate power!

Comment 60-3: Texas is ready for a new way to power our lives; give Texa[s] a chance for a 

cleaner, safer power of energy ...
Appendix A

A-8 

Comment 61-2: There are safer, cleaner alternative ways to generate the same power that 

exist today and should be used. 

Comment 62-2: Safer, cleaner alternative ways to generate the same power exist today and 

should be used. 

Comment 69-2: Safer, cleaner alternative ways to generate the same power exist today and 

should be used.

Comment 73-2: Rather than pushing for more water-consuming nuclear power plants, Texas 

needs to focus more on the development of renewable energy sources such as wind and solar.

While many promises are made as to the safety of nuclear power, recent history demands we 

not place too much reliance on them. Some things do not readily lend themselves to 

engineering solutions. I believe nuclear power is one of those things, and thus I am opposed to 

the requested re-licensing.

Comment 74-1: To ensure the safety of my family and other Texas families, I believe the 

re-licensing of these two reactors for an additional [20] years should be halted for safety 

reasons. There are safer and cleaner alternatives than outdated reactors. These alternatives 

(solar, wind, etc.) should be strongly considered.

Comment 77-2: There are safer and cleaner ways to generate power today that we need to 

support and use. Renewable energy sources are everywhere in Texas and could replace more 

dangerous sources if funded and supported. Another factor to think about is the huge amount 

of water used in the reactors. The water from the Colorado River is needed to farming, cattle 

and families. Are we not just creating another problem by using energy sources that use so 

much water?

Comment 79-2: Safer, cleaner alternative ways to generate the same power exist today and 

should be used. Studies have found that energy efficiency and renewable energy sources, 

which are abundant in Texas, could replace the power generated by these two old nuclear 

reactors.

Comment 80-2: Safer, cleaner alternative ways to generate the same power exist today and 

should be used. Studies have found that energy efficiency and renewable sources, which are 

abundant in Texas, could replace the power generated by these two old nuclear reactors.

Response: These comments provide input (or data) for the staff’s environmental analysis of 

the alternatives to license renewal, including the alternative of not renewing the operating 

license—also known as the “no-action” alternative. In Chapter 8 of this supplemental 

environmental impact statement (SEIS), the staff evaluated the alternatives to license renewal. 

These include new nuclear generation, natural-gas-fired combined-cycle generation, 

supercritical coal-fired generation, combination alternative, and purchased power. In addition, in 

Chapter 8 of this SEIS, the staff considered many other options that were subsequently 

dismissed for reasons of technical, resource availability, or commercial limitations. These 

include offsite nuclear, gas and coal-fired capacity; energy conservation and energy efficiency; 

wind power; solar power; hydroelectric power; wave and ocean energy; geothermal power; 

municipal solid waste; biomass; biofuels; oil-fired power; fuel cells; and delayed retirement.

A.1.2 Socioeconomic Impact of STP, Units 1 and 2

The original sources for the comments in this category (socioeconomic) can be found at the 

back of the Scoping Summary Report and are labeled with the following identifiers: 1-2, 3-1, 

5-2, 6-2, 8-1, 9-1, 10-1, 13-1, 14-1, 20-2, 23-1, and 24-1. These comments are extracted from 

the original sources.
Appendix A

A-9 

Comment 1-2: STP is the largest employer in Matagorda County with more than 

1,200 employees and for 30 years has been a key part of the county and local communities. 

The company’s employees are active in the local community, serving on school boards, 

chambers and in civic and service organizations.

For over 20 years, [the] existing [STP] units have supplied safe, clean and reliable energy to 

more than 2 million Texas homes while also providing permanent, well-paying jobs. The facility 

is a recognized industry leader in production, reliability and safety, as well as being focused and 

committed to the safety of its employees and the surrounding communities.

Comment 3-1: With that being stated, STP makes it obvious. STP is the largest employer to 

the county, their employees stay active in numerous organizations, and many serve as elected 

officials. They have a very high importance to safety as well as the environment. Their 

employees set the standard for their industry. Just last October, STP was named one of 

America’s safest companies, the first nuclear facility to ever be honored with that award.

In 2008, STP started its educational incentive program as part of its workforce development 

efforts. It represents a $4.2 million investment that provides great opportunities for well-paying 

jobs in this community. For over 20 years, the facility has produced safe, reliable energy to the 

citizens of Texas, and for the past [7] consecutive years, STP has produced more electricity 

than any other two-unit nuclear plant in the country.

The license extension of STP will continue to provide jobs and economic benefits to our local 

community. 

Comment 5-2: Our employees try to contribute and try to continue to do what they can to 

improve life within this community by serving, as the judge said, on various boards and 

providing leadership positions, and we’re thankful that you give us that opportunity.

Comment 6-2: During the record low temperatures when there were problems in Texas with 

other sources of power, our local plant didn’t have any problems keeping the power generating 

for Texans.

The culture of continuing improvement for all aspects of power generation overflows in the 

community. STP[NOC]’s contributions to our local charities, our chambers of commerce and 

civic groups provide the commitment to our future and our joint success. They give both time 

and money to make sure Matagorda County is the best in all of Texas.

Comment 8-1: My name is Cheryl Stewart, and I’m on the Bay City Community Development 

Corporation Board and also the Historic Commission, and I’m here today to inform you of the 

many ways that I have personally seen STP impact our community in a positive way.

STP contributed $100,000 to the Center for Energy Development and currently provides staffing 

to train our community’s young adults. STP employees have been strong leaders in our 

strategic planning for the future of this community with our Bay City Matagorda United Plan. 

STP employees have also invested in the renovation of our historic downtown district and its 

beautification efforts. I have also served with STP employees on various community boards 

and have witnessed firsthand their dedication, their desire to be good neighbors, and their 

commitment to our community.

I am sure that our community would experience a huge loss without the involvement and 

support of STP. 

Comment 9-1: The importance of STP to that future [cannot] be overemphasized. My employer 

is an educational partner with STP and their contribution to the future of our community through 

support of education is unprecedented in my 20 years of higher education experience.
Appendix A

A-10

Comment 10-1: STP personifies the best type of economic development project that a 

community could want. It’s created a large number of jobs that have been filled with highly 

educated and highly skilled workers. It pays wages far above the county average. It’s greatly 

enhanced the tax base of Matagorda County and to the taxing entities in whose location it is 

situation. It makes significant annual financial contributions to civic, educational, and 

promotional programs benefitting all of the county. It has created and funded a major 

grow-your-own technical education program, providing good career opportunities for all of our 

local youth. Its employee and their families are extensively involved in all aspects of our 

community and political life, and, by so doing, they make Matagorda County a much better 

place in which to live for all the rest of us.

Comment 13-1: And have you ever wondered what Bay City and Matagorda County would be 

like if we didn’t have South Texas Nuclear Operating Company [STPNOC] here? There isn’t a 

day that goes by that we don’t run into or communicate with STP employees. They’re involved 

throughout our community, and I really have a hard time imagining what it would be like here 

without them because they’re such a huge asset to our community.

And, of course, we love to show off our assets, and I’m proud to say that every time I meet 

someone I always talk about we’re the home of a nuclear power plant, because I’m just really 

proud of that. And, because of that, I’ve also invited all of our surrounding economic 

development associates to come and visit STP because I want them to see the high level of 

security and safety that they operate in every day. And, I’ve got them actually scheduled next 

month, so Mr. Halpin, hopefully you can stop by and say hello.

But, as an economic developer and resident of Matagorda County, I’m very thankful to have 

such a great asset in our community, and they will not only have a positive impact but an 

excellent impact on our taxes, community development, and our environmental justice. 

Comment 14-1: I don’t have a lot of knowledge on technical skills about nuclear energy, so I’m 

just going to limit my comments to the social environmental impact that STP has had on this 

community.

Matagorda County, like many rural communities, over the years has suffered from brain drain, 

where your best and your brightest tend to leave and seek their fortunes other places. Well, 

STP has helped to reverse that trend in Matagorda County. Not only does it provide great 

paying jobs for our youth that even go off to college and return to become productive citizens in 

this community, they have reduced the amount of exodus of kids leaving this community in the 

first place with the creation of the Center for Energy Development where we can now grow our 

own.

The social environmental impact of that, just in and of itself, has been tremendous. If we were 

to track the intellectual scale of Matagorda County within the last 20 years, you can begin to see 

that if you start off with the census of 2000, the number of high school graduated individuals in 

Matagorda County represented about one-third, another group of individuals that did not have a 

high school diploma represented another third. So effectively, basically, two-thirds of the 

population of Matagorda County had a high school diploma or less.

If you begin to look at the recent trend since the [STP] has been in this community, you can see 

that trend reversing and the numbers of educated citizens of this community going up.

When I returned to Matagorda County several years ago, I became actively involved in a lot of 

the nonprofit organizations. The premier nonprofit organization for this community was United 

Way, but at that time, unfortunately, United Way was under poor leadership and dysfunctional.
Appendix A

A-11

Thanks to the leadership of two employees from STP, one by the name of Gerald Wilson, 

another by the name of Chris Johnson, who took the leadership of the United Way and made it 

the organization that it is today that’s supporting over 30 other non-profit organizations in this 

community, there are others that could talk more eloquently about the economic impact of STP, 

but the ancillary benefit of its employees serving on nonprofit boards, and not to mention our 

faith-based communities through their tithes, their offerings that support churches and other 

community-based organizations, that contribution is almost immeasurable.

Comment 20-2: What should you focus on? Obviously, our environmental concerns are a huge 

part of this. I’m [with] the Convention and Visitors Bureau, and one of our main focuses is 

bringing tourists down to Matagorda County to see what we have to offer.

Comment 23-1: And I’d just like to say that, on behalf of Babe Ruth, we’re very grateful for 

everything STP does for us as an organization. They’re a major sponsor in all of our events. 

Over the last [10] years, we’ve hosted [4] regional tournaments and [11] or [12] state 

tournaments, and without STP[NOC]’s support, we would never have been able to participate in 

those tournaments or even host those tournaments. 

On the economic standpoint, Mr. Head said earlier last year we hosted a regional tournament. 

We had five states come to visit Bay City, over 400 visitors in town, over 100,000 new dollars 

just last year, and without STP supporting that, we wouldn’t have been able to host that 

tournament. So, we’d like to thank them. 

Not only do they help us monetarily with our tournaments, but their employees also volunteer 

with us, and we’d like to thank them for their employees and letting them volunteer. 

Over the last [10] years, like I said, we’ve hosted about 15 tournaments and probably half a

million new dollars in Matagorda County over the last [10] years.

Comment 24-1: You may ask why I’d want to come down from Austin to talk to you. Well, 

Austin is a 16 percent partner in [Units 1 and 2], and if you look back over the history of the 

project, we’ve got a lot less reason to celebrate this plant than may be some people who live 

here do. I’m not going to talk a lot about jobs, but I’m going to wrap up with that tonight. 

But, Austin’s experience with [Units] 1 and 2 was a nightmare. We had it thrust upon us by 

politicians who were determined to continue to take public votes until we bought a share of the 

plant. We tried to get out of the plant at one point, tried to sell our 16 percent share, and 

[cannot]. 

The problem was at its worst in the ’90s when 42 cents out of every dollar that we paid on a 

utility bill was going for debt service at NRG. For our 16 percent share, we were paying almost 

half of our utility bill for debt service on the project.

Response: These comments provided input (or data) for the staff’s environmental analysis of 

the socioeconomic impacts of STP on local and regional communities. The comments include 

socioeconomic-related items such as taxes, employment, education, tourism, and public and 

civic services. 

The socioeconomic impacts of renewing the STP operating license and alternatives to license 

renewal are discussed in Sections 2.2.9, 4.9, 8.1.8, 8.2.8, 8.3.8, 8.4.8, 8.5.8, and 8.7.8 of this 

SEIS.

A.1.3 Water Usage

The original sources for the comments in this category (water usage) can be found at the back 

of the Scoping Summary Report and are labeled with the following identifiers: 25-4, 29-3, 32-2, 
Appendix A

A-12

36-5, 37-3, 39-4, 40-3, 41-2, 45-4, 47-2, 51-3, 53-3, 54-2, 55-3, 59-3, 60-2, 62-4, 63-2, 64-3, 

67-2, 71-2, 75-2, 77-2, and 80-4. These comments are extracted from the original sources.

Comment 25-4: There is a problem with the leaking main cooling reservoir [MCR], which was 

described and documented in the license application for Units 3 and 4. There needs to be 

tracking of where the water is going. Is it reaching the Gulf, where is it going, what is it doing? 

That should be part of the re-licensing study and analysis.

Water use is an increasing issue. Up until this point, the highest use that I know of through 

researchers looking at this is 49 percent of the Colorado River has been used for cooling 

purposes, and I know a couple of summers ago there was a lot of pumping going on to refill the 

reservoir when it got kind of low. 

It’s a problem for those of us in Austin. The Colorado River water has to serve a lot of 

purposes. Rice farmers need it; we’re going to need it for many, many purposes, recreation, 

fishing on our end. And, Lake Travis levels were at an all-time low several years ago. Every 

single dam on the whole lake was closed; you couldn’t put a boat in.

And, we would like to see something shift to where this much water was no longer required. 

Certainly, you’re still going to have to still cool spent fuel rods and so on and so forth, but it is a 

question when you look at continuing the reactors’ life.

Comment 29-3: Vast water consumption requirements for these reactors add a hidden cost to 

taxpayers, farmers, ranchers and other industries. As water becomes more scarce in Texas, 

this becomes a very high risk should there be a meltdown like Japan.

Comment 32-2: We have been suffering for many years from drought conditions here in Texas. 

Given the huge amount of water needed for normal operation and to avert nuclear catastrophe, 

we would be better served to use the little water we have for agriculture and residential use.

Comment 36-5: STP requires a large amount of cooling water to operate, critical, as seen in 

Japan. Texas is facing more and more serious water shortages, as population rises and global 

warming effects take place. The need for water for other purposes than STP will grow. STP 

should relinquish its water use and shut down.

Comment 37-3: Vast consumption of water use, largely Colorado River water, which is 

increasingly needed for drinking water, livestock, and farming. The [MCR] is leaking out the 

bottom. How and when will this be repaired? Climate change—rising temperatures could affect 

whether there is enough cool water to cool the reactors.

Comment 39-4: Vast consumption of water use, largely Colorado River water, which is 

increasingly needed for drinking water, livestock, and farming in an era of more frequent and 

lengthy periods of drought. The [MCR] is leaking out of the bottom: How and when will this be 

repaired? Climate change considerations: The rising atmospheric temperatures could affect 

whether there is enough cool water to cool the reactors.

Comment 40-3: Also, as you know, nuclear power supplies require a lot of water for cooling 

purposes. Once again, the State of Texas is experienced drought in 98 [percent] of its counties. 

Let’s save the water for agricultural purposes.

Comment 41-2: The reactors consume vast quantities of water; use largely from the Colorado 

River; water that is needed for drinking water.

Comment 45-4: These reactors consume vast quantities of water use, largely Colorado River 

water, which is increasingly needed for drinking water, livestock, and farming. Drought is 

expected to increase in our region. We are concerned that there will not be adequate water to 

cool the reactors in an emergency or that the water will not be cool enough to effectively cool 
Appendix A

A-13

the reactors. Some U.S. reactors have had to shut down due to high water temperatures, and 

this could [result in a] scenario [that] could worsen with climate change impacts, leaving us with 

a dangerous situation and a shortage of power during intense heat waves. 

The [MCR] is leaking out the bottom, as documented in the license application for STP 3 

[and] 4. The reactors should not be relicensed when this serious condition remains unresolved. 

How and when will this be repaired? What studies have been done by the NRC on this serious 

problem? How can relicensing even be considered until this situation is corrected? Where is 

the water going, and how extensive is the radioactivity that may be leaking into the Gulf of 

Mexico [or the] Colorado River [or both]? 

Comment 47-2: We have limited access to freshwater that can be used for this facility. The 

priority should be for drinking water, livestock, and farming. I understand that the [MCR] is 

leaking out the bottom. How and when will this be repaired?

Comment 51-3: These reactors consume vast quantities of water use, largely from the 

Colorado River, water that is needed for drinking water, livestock, and farming.

Comment 53-3: These reactors consume vast quantities of water use, largely from the 

Colorado River, water that is needed for drinking water, livestock, and farming.

Comment 54-2: The reactors would affect the Austin area by consuming vast quantities of our 

drinking water from the Colorado River ...

Comment 55-3... these reactors consume vast quantities of water use, largely from the 

Colorado River, water that is needed for drinking water, livestock and farming;

Comment 59-3: Leave the Colorado River for other purposes—drinking, livestock, and farming.

Comment 60-2: Please help protect Americans, Texans, and all human beings that come into 

contact with the Texas Colorado River from having it depleted by renewing these reactors 

licenses[,] to continue consuming vast quantities. Protect the waterways from being poisoned in 

the event of emergencies at nuclear plants.

Comment 62-4: These reactors consume large quantities of water use, largely from the 

Colorado River, water that is needed for drinking water, livestock, and farming.

Comment 63-2: Too much water is used to cool the reactors! Too much water is used. It’s 

dangerous.

Comment 64-3: Too much water is wasted! There goes the drinking water; all gone and toxic! 

Please do not relicense these two reactors.

Comment 67-2: The vast amount of water taken up by these reactors is very much needed for 

other purposes.

Comment 71-2: Nuclear reactors use large quantities of water, water that could be used for 

drinking, livestock, and farming.

Comment 75-2: These reactors consume vast quantities of water use, largely from the 

Colorado River[;] water that is needed for drinking water, livestock[,] and farming.

Comment 77-2: There are safer and cleaner ways to generate power today that we need to 

support and use. Renewable energy sources are everywhere in Texas and could replace more 

dangerous sources if funded and supported. Another factor to think about is the huge amount 

of water used in the reactors. The water from the Colorado River is needed [for] farming, 

cattle[,] and families. Are we not just creating another problem by using energy sources that 

use so much water?
Appendix A

A-14

Comment 80-4: These reactors consume vast quantities of water use, largely from the 

Colorado River[;] water that is needed for drinking water, livestock, and farming.

Response: These comments provided input (or data) for the staff’s environmental analysis of 

water resource impacts of STP on local and regional communities. These comments raise 

concerns about the water usage from the Colorado River and leakage from the MCR. The staff 

discusses water usage impacts in Sections 2.2.4, 2.2.5, 4.3, 4.4, 8.1.2, 8.1.3, 8.2.2, 8.2.3, 8.3.2, 

8.3.3, 8.4.2, 8.4.3, 8.5.2, 8.7.2, and 8.7.3 of this SEIS. 

A.1.4 Human Health 

The original sources for the comments in this category (human health or Radiation Impact) can 

be found at the back of the Scoping Summary Report and are labeled with the following 

identifiers: 25-1, 29-4, 36-3, and 45-6. These comments are extracted from the original 

sources.

Comment 25-1: I also have concerns about the re-licensing of reactors 1 and 2. I think there 

are a number of issues that need to be looked at carefully during this process and bearing 

worker safety in mind. One of them is tritium, and basically, there has been tritium showing up 

in wells on the site. This needs to be looked into thoroughly, as well as tritium in the Colorado 

River, and documented, measured, carefully analyzed to see if it’s safe to continue down this 

path at this point in time.

Comment 29-4: There is currently a leak in the bottom. What are the health implications to 

wildlife and people of this leak? When will it be fixed? They have not repaired this, how can they 

be trusted for another 20 years?

Comment 36-3: I have heard the news reports that the leakage of plutonium and cesium is not 

a cause for concern. As a physician interested in this area, I know that this is ridiculous. I 

remember how much polonium [alpha emitter] was required to assassinate a Russian person in 

the UK. 

Comment 45-6: We are concerned about increasing tritium levels in wells [on site] and in the 

Colorado River. Extensive testing should occur for all organisms in the region, and exposure of 

whooping cranes to tritium and other radionuclides should be examined since they are an 

endangered species and their winter grounds are only 35 miles from the STP site.

Response: These comments provided input (or data) for the staff’s environmental analysis of 

human health and environmental impacts related to possible radioactive leaks from STP.

To ensure that STP is operated safely, the NRC licenses the plant and plant operators and 

establishes license conditions for safe operation. The NRC provides continuous oversight of 

STP through its reactor oversight process (ROP) to verify that operations are in accordance with 

NRC regulations. The NRC has full authority to take necessary actions to protect public health 

and safety and the environment, and it may demand immediate STPNOC actions, up to and 

including a plant shutdown.

Radiation doses to members of the public from the current operations of STP are evaluated in 

the SEIS in Section 4.8.2. In that section, the staff reviewed the radioactive releases from STP 

(i.e., radioactive gaseous and liquid effluents, radiation from radioactive waste storage buildings, 

radiological impacts from refueling and maintenance activities, and tritium leaks) and the results 

of STPNOC’s radiological environmental monitoring program (REMP) (i.e., analysis of air, water 

(surface, ground, and drinking), sediment, vegetation, and aquatic and terrestrial biota for 

radioactivity). Based on its review, the staff concluded that the radiological impacts to members 

of the public were within NRC’s and U.S. Environmental Protection Agency’s (EPA’s) dose
Appendix A

A-15

standards, and there were no radiological effects to the environment and non-human species 

(i.e., local biota) from plant operation. 

The staff also evaluated the STP REMP. The REMP quantifies the environmental impacts 

associated with radioactive releases from the plant. The REMP monitors the environment over 

time, starting before the plant operates to establish background radiation levels and throughout 

its operating lifetime to monitor radioactivity in the local environment. The REMP provides a 

mechanism for determining the levels of radioactivity in the environment to ensure that any 

accumulation of radionuclides released into the environment will not become significant as a 

result of plant operations. Based on the review of several years of data, the staff concluded that 

there were no measurable impacts to the environment as a result of radioactive releases from 

STP. 

In summary, the NRC provides continuous oversight of STP through its ROP to verify that they 

are being operated in accordance with NRC regulations. STP is required to maintain its 

radioactive effluent release program in compliance with NRC regulations and consistent with 

EPA standards. The NRC will continue to inspect STPNOC’s compliance with radioactive 

effluent. 

A.1.5 Postulated Accidents

The original sources for the comments in this category can be found at the back of the Scoping 

Summary Report and are labeled with the following identifiers: 25-3, 37-2, 39-2, 42-1, 45-2, and 

48-1. These comments are extracted from the original sources.

Comment 25-3: [I]n 1982, there was a study done for the [NRC] called the [CRAC 2] Study. It 

found that if there were an accident—and they were looking at Units 1 and 2—that there would 

be 18,000 early deaths. They would also be followed by thousands of cancers. That study has 

not been updated. The population in some of this region has grown, and it needs to be looked 

at again to find out what is the reality of the situation today, and that needs to be compared to 

other ways of generating electricity.

Comment 37-2: Risks of an accident, fires, or explosions at one or more reactors at the site, 

risks that could increase with aging reactors NRC’s 1982 CRAC 2 study found that there could 

be 18,000 early deaths if a serious accident occurred at the STP site.

Comment 39-2: Risks of an accident, fires, or explosions at one or more reactors at the site, 

risks that could increase with aging reactors. [NRC’s] 1982 CRAC 2 study found that there 

could be 18,000 early deaths if a serious accident occurred at the STP site.

Comment 42-1: The [license renewal application (LRA)] is inadequate because it: (a) fails to 

adequately address the applicant’s capacity to deal with fires and explosions that cause a loss 

of large areas of the plant—the mitigative strategies for addressing fires and explosions are 

inadequate to address the consequences of events such as the impacts of large commercial 

aircraft crashing into the reactors or related facilities, (b) fails to describe the means that would 

be used to determine radiation exposures to fire and explosion responders, and (c) fails to 

describe the means that would be used to protect fire and explosion responders from excessive 

radiation exposures.

Comment 45-2: We are all too aware of the fact that meltdowns can and do happen, and a 

recent Union of Concerned Scientists report notes that there were 14 near misses in the U.S. in 

2010. NRC’s 1982 CRAC 2 study found that there could be 18,000 early deaths if a serious 

accident occurred at the ST(N)P site, followed by thousands of cancers.
Appendix A

A-16

Comment 48-1: The [LRA] is inadequate because it: (a) fails to adequately address the 

applicant’s capacity to deal with fires and explosions that cause a loss of large areas of the 

plant—the mitigative strategies for addressing fires and explosions are inadequate to address 

the consequences of events such as the impacts of large commercial aircraft crashing into the 

reactors or related facilities, (b) fails to describe the means that would be used to determine 

radiation exposures to fire and explosion responders, and (c) fails to describe the means that 

would be used to protect fire and explosion responders from excessive radiation exposures

Response: These comments provided input (or data) on various aspects of severe accidents 

associated with fire and explosion hazards, ranging from the applicability of results from earlier 

NRC consequence studies (e.g., CRAC) to emergency management operation. The 

evaluations of STPNOC’s severe accident analysis are discussed in Section 5.2 of this SEIS. 

The NRC and the global nuclear research and safety community have done extensive research 

over the past three decades evaluating reactor accidents and how they could affect the public. 

Earlier studies (e.g., NUREG/CR-2239, Technical Guidance for Siting Criteria Development, 

commonly referred to as the 1982 Siting Study or CRAC 2 Study) had uncertainties and 

conservatisms and did not include information on current plant design, operation, accident 

management strategies, emergency preparedness procedures, or post-9/11 enhancements to 

mitigative measures. Earlier work was also limited by both computer hardware and software 

available at that time. Researchers attempted to overcome these limitations by simplifying 

some estimates or assumptions concerning possible damage to the reactor core, the possible 

radioactive contamination that could be released, and possible failures of the reactor vessel and 

containment buildings. These efforts led to overestimates in the results, particularly in the 

1982 Siting Study (or CRAC 2 Study) report. This report was meant to assist the NRC staff in 

considering regulations for choosing nuclear power plant locations, but it has been regularly 

misinterpreted and misused as an estimate of accident consequences. Since those early 

studies, information from both NRC and cooperative foreign research has greatly increased our 

understanding of the timing and magnitude of possible radioactive releases from potential 

accidents at nuclear power plants. 

The NRC established a research project in 2006 to update its assessment of severe reactor 

accident scenarios and their potential consequences to human health. This research project, 

titled “State-of-the-Art Reactor Consequence Analyses (SOARCA),” was designed to develop 

best estimates of the public health effects that might result from a radiological release during a 

nuclear power plant accident. The SOARCA project used state-of-the-art computer codes to 

calculate accident progression and offsite consequences for important scenarios at two plants, 

Peach Bottom, a boiling-water reactor (BWR), and Surry, a pressurized-water reactor (PWR). 

These codes have been continuously updated to incorporate decades of experimental research. 

The SOARCA project had cooperation from the licensees of these plants to model them in great 

detail as they exist in their current state and include operator action timelines based on 

plant-specific procedures. The project also modeled the use of additional equipment and 

strategies required by the NRC following the terrorist attacks of September 11, 2001, to further 

improve each plant’s capability to mitigate events involving a loss of large areas of the plant 

caused by fire and explosions. 

SOARCA results show that when operators are successful in using available onsite equipment 

during the accidents analyzed in SOARCA, they can either (a) prevent the reactor from melting 

or (b) delay or reduce releases of radioactive material to the environment. Even if operators are 

unsuccessful in stopping the accident, SOARCA shows that the accidents progress more slowly 

and release much smaller amounts of radioactive material than calculated in the 1982 Siting 

Study or CRAC 2 Study. Therefore, public health consequences from severe nuclear reactor 

accident scenarios are smaller than previously calculated. The delayed releases calculated 
Appendix A

A-17

provide more time for emergency response actions, such as evacuating or sheltering. All 

modeled scenarios in SOARCA showed essentially zero early fatalities. In contrast, the 

1982 Siting Study calculated 92 mean early fatalities for Peach Bottom, 45 for Surry, and 

6.51 (not 18,000)2 for STP conditional on the occurrence of a hypothetical large source term 

being released. In addition, in SOARCA, the calculated individual long-term risks of dying from 

cancer from exposure to radiation from these accidents are very small—millions of times lower 

than the general risk of dying from cancer in the U.S. from all causes.

Because STP and the Surry plant studied in SOARCA are both Westinghouse-designed PWRs 

with large dry containments, the insights gained from the SOARCA project regarding accident 

progression and offsite health consequences can generally be applied to the STP site.

More information regarding the SOARCA project is available on NRC’s Web site at 

http://www.nrc.gov/about-nrc/regulatory/research/soar.html. 

A.1.6 Terrestrial or Aquatic Ecology

The original sources for the comments in this category can be found at the back of the Scoping 

Summary Report and are labeled with the following identifiers: 18-1, 20-3, 44-2, and 45-7. 

These comments are extracted from the original sources.

Comment 18-1: I want to touch on two aspects of the review. One is going to be the 

environmental aspect. It’s very important when you talk about Matagorda County—and I’ll do 

just a little bit of a commercial—we have a very, very sensitive area in that we have the 

freshwater from our Colorado River, two bays, estuaries, as well as the Gulf of Mexico. We are 

the North American Christmas bird count winner about [11] out of the last [12] years. It was 

foggy one morning, and we missed some of those birds. But, as you see that as we’ve got such 

a great ecological area here the whole time Units 1 and 2 have been operating. So, we’re very, 

very proud of the fact that the [STPNOC], with Units 1 and 2, continues to operate in a strong 

fashion while our environment is protected.

Comment 20-3: What should you focus on? Obviously, our environmental concerns are a huge 

part of this. I’m [with] the Convention and Visitors Bureau, and one of our main focuses is 

bringing tourists down to Matagorda County to see what we have to offer. Good thing one of 

our sights to see is STP, as well as all around STP we have tons of fishing, birding, we have 

farm lands and everything else, and from what I’ve seen, there have been no concerns with 

those at all, as I grew up fishing right below STP on the Colorado River. And, I would like to 

thank STP for providing that to me, providing the safe waters and the safe grounds for me to do 

that on.

Comment 44-2: In addition, the existing South Texas units need to be evaluated to see if they 

will need to be modified to meet the newly proposed cooling water requirements that the [EPA] 

announced this week.

Comment 45-7: We are concerned about increasing tritium levels in wells [on site] and in the 

Colorado River. Extensive testing should occur for all organisms in the region, and exposure of 

whooping cranes to tritium and other radionuclides should be examined since they are an 

endangered species and their winter grounds are only 35 miles from the STP site.

 

1

 The 1982 Siting Study calculated 5.2 mean early fatalities for STP for the SST1 source term. This value is based upon a standard 

1,120 MWe PWR. When corrected for the actual electrical output (1410 MWe), the result is 6.5 mean early fatalities. 

2 The 1982 Siting Study calculated 18,000 early fatalities as the 99th percentile value, and it is dependent upon the SST1 source 

term release, assuming New York City meteorology and Indian Point population and wind rose as well as no evacuation. This was 

included as a sensitivity to show the effect of evacuation distance on early fatalities and was not meant to be a realistic estimate of 

the offsite health consequences of a severe nuclear reactor accident. 
Appendix A

A-18

Response: 

These comments provided input (or data) for the staff’s environmental analysis of the ecology 

impacts of STP. The staff discusses these impacts in Sections 2.2.6, 2.2.7, 4.5, 4.6, 4.8, 8.1.4, 

8.1.5, 8.2.4, 8.2.5, 8.3.4, 8.3.5, 8.4.4, 8.4.5, 8.5.3, 8.7.4, and 8.7.5 of this SEIS. 

A.1.7 Uranium Fuel Cycle and Waste Management 

The original sources for the comments in this category can be found at the back of the Scoping 

Summary Report and are labeled with the following identifiers: 29-5, 32-4, 33-2, 34-1, 36-2, 

37-4, 39-5, 43-2, 45-5, 46-2, 47-3, 49-3, 51-4, 53-4, 54-4, 55-4, 59-4, 61-4, 62-5, 63-3, 64-2, 

69-4, 71-3, 75-3, 77-3, 79-3, 80-5. These comments are extracted from the original sources. In 

summary, these comments express concerns about transportation of radioactive materials, 

long-term stewardship of nuclear waste, and uranium mining. 

Comment 29-5: Whose backyard is the waste being transported through? [In] whose backyard 

is the waste being dumped?

Comment 32-4: Lastly, there is no way this can be justified as a result of the lack of safe 

storage for thousands and thousands of years of the nuclear waste. Please reject the renewal 

applications. The danger to our citizens is too great. 

Comment 33-2: Uranium mining is a health issue. Nuclear waste remains a serious threat to 

future generations as well as the current population.

Comment 34-1: Please do not approve the licensing. Nuclear waste is too dangerous.

Comment 36-2: I also know, from following WCS in Andrews, Texas, that there is no safe 

disposal for LLRW [low-level radioactive waste], and still no safe disposal for the high-level 

waste fuel rods such as are melting in Japan today.

Comment 37-4: There is no adequate solution for radioactive waste, so it makes sense to stop 

generating more.

Comment 39-5: There is no adequate solution for radioactive waste, so it makes sense to stop 

generating more.

Comment 43-2: As we have seen in the last few weeks, nuclear energy is not as safe as made 

out to be, and there are too many problems with disposal that have not been solved.

Comment 45-5: It is time to stop generating more radioactive waste since there is no safe 

storage and disposal solution, even after attempts have been made for some [60] years. 

Relicensing would the creation of waste. There may not be enough room for even the so-called 

[LLRW] at the planned West Texas radioactive waste dump, since there is an attempt to allow 

Out of Compact waste[,] and the volume and curies limits may be reached long before all STP 

waste could be shipped. There is still no “high-level” repository for spent fuel rods.

Comment 46-2: I’m opposed to their continuation for all the usual reasons that any kind of 

accident and even a Category 4 or 5 hurricane-induced storm surge could remove external 

supports such as cooling ponds or water access (and who knows what hammering debris-laden 

waves on top of the storm surge could do), plus disposal of nuclear waste—no human 

technology is foolproof and totally isolated for thousands of years!

Comment 47-3: At the most fundamental level[,] we cannot justify generating more radioactive 

waste when there is no adequate solution for dealing with it.

Comment 49-3: Every nuclear power plant is a potential disaster waiting to happen[,] and every 

nuclear power plant is a long-term disaster by the toxic waste they generate.
Appendix A

A-19

Comment 51-4: There is no adequate solution for radioactive waste, so it makes no sense to 

continue generating more. 

Comment 53-4: There is no adequate solution for radioactive waste[,] so it makes no sense to 

continue generating more.

Comment 54-4: There is no adequate solution for radioactive waste, so it makes no sense to 

continue generating more.

Comment 55-4: [T]here is no adequate solution for radioactive waste, so it makes no sense to 

continue generating more. 

Comment 59-4: Until there is an adequate solution for radioactive waste, we should not 

continue to generate more.

Comment 61-4: There is no adequate solution for radioactive waste, so it makes no sense to 

continue generating more.

Comment 62-5: There is no adequate solution for radioactive waste, so it makes no sense to 

continue generating more.

Comment 63-3: What about waste? Radioactive waste is terrible to contend with.

Comment 64-2: Too much water is wasted! Way too much [water] daily to cool it!

These [...] dangerous radioactive waste! Is not safe. What are you going to do with the 

radioactive waste?

Comment 69-4: There is no adequate solution for radioactive waste, so it makes no sense to 

continue generating more.

Comment 71-3: There is no solution for the disposal of radioactive waste, so it makes no sense 

to continue generating more. 

Comment 75-3: There is no adequate solution for radioactive waste, so it makes no sense to 

continue generating more.

Comment 77-3: Radioactive waste is and will continue to be a big problem[,] so why would we 

go in that direction. Leadership and creating thinking is needed at this moment in history. 

Please be part of solving problems and not adding new problems.

Comment 79-3: There is no adequate solution for radioactive waste, so it makes no sense to 

continue generating more.

Comment 80-5: There is no adequate solution for radioactive waste, so it makes no sense to 

continue generating more.

Response: These comments raise concerns about the uranium fuel cycle and waste 

management. The staff addresses the environmental impacts of the uranium fuel cycle and 

waste management in Chapter 6 of this SEIS. 

A.2 Comments Received on the Draft SEIS

On December 5, 2012, the NRC issued the Generic Environmental Impact Statement for 

License Renewal of Nuclear Plants Regarding South Texas Project, Draft Report for Comment 

(NUREG 1437, Supplement 48, referred to as the draft SEIS) to Federal, tribal, state, and local 

government agencies and interested members of the public. The U.S. Environmental Protection 

Agency (EPA) issued its Notice of Availability on December 14, 2012 (77 FR 74479) that 
Appendix A

A-20

included the draft SEIS. The public comment period ended on February 22, 2013. As part of 

the process to solicit public comments on the draft SEIS, the NRC did the following:

• placed a copy of the draft SEIS at the Bay City Public Library in Bay City, 

Texas,

• made the draft SEIS available in the NRC’s Public Document Room in 

Rockville, Maryland,

• placed a copy of the draft SEIS on the NRC Web site, on December 5, 2012, 

at http://www.nrc.gov/reading-rm/doccollections/nuregs/staff/sr1437/supplement48/,

• provided a copy of the draft SEIS to any member of the public that requested 

one,

• sent copies of the draft SEIS to certain Federal, tribal, state, and local 

government agencies,

• published a notice of availability of the draft SEIS in the Federal Register on 

December 18, 2012 (77 FR 74882),

• filed the draft SEIS with the EPA, and 

• announced and held two public meetings at the Bay City Civic Center in Bay 

City, Texas, on January 15, 2013, to describe the preliminary results of the 

environmental review, answer any related questions, and take public 

comments.

Approximately 30 people attended the meetings, and 6 attendees provided oral comments. A 

certified court reporter recorded the oral comments and prepared written transcripts of the 

meeting. A meeting summary is available in ADAMS (ADAMS No. ML13023A344). In addition 

to the comments received at the public meetings, the NRC received nine comment submittals 

(i.e., individual e-mail, entry at Regulations.Gov, or letters with comments). Excerpts from the 

public meeting transcripts and all letters and e-mails are included in Section A.3 with labels 

marking individual comments.

To identify each individual comment, the NRC reviewed the transcript of the public meetings 

and each e-mail and letter received on the draft SEIS. The NRC identified statements related to 

the proposed action and recorded the statements as comments.

Each commenter was given a unique identifier, so every comment could be traced back to its 

author. Table A-2 identifies the individuals who provided comments applicable to the 

environmental review and the Commenter ID associated with each person’s set of comments. 

The individuals are listed in the order in which they spoke at the public meeting and in numerical 

order for the comments received in the transcript or by e-mails or letters.

Table A–2. Individuals Providing Comments During the Comment Period

Commenter Commenter ID Affiliation (If Stated) ADAMS No.

Owen Bludau STP-1 Matagorda County Economic 

Development Corporation (MCEDC)

ML13023A334

Carolyn Thames STP-2 Bay City Resident ML13023A334

Terry Farrar STP-3 Farrar Financial Group ML13023A334
Appendix A

A-21

Commenter Commenter ID Affiliation (If Stated) ADAMS No.

Karen Hadden STP-4 Sustainable Energy and Economic 

Development

ML13023A334

Susan Dancer STP-5 South Texas Association for 

Responsible Energy (STARE)

ML13023A334

Eugene Davis STP-6 Crisis Center ML13023A334

Marvin Lewis STP-7 Philadelphia Resident ML12356A233

Sonia Santana STP-8 Austin Resident ML13017A405

John Elder STP-9 San Antonio Resident ML13025A357

Cynthia Weehler STP-10 Austin Resident ML13025A358

Elizabeth Tobin STP-11 San Antonio Resident ML13025A359

Kenneth Taplett STP-12 STP Nuclear Operating Company ML13044A496

Mary Sixwomen 

Blount

STP-13 Apalachicola Creek Indians ML13072A072

Debra Griffin STP-14 EPA Region VI ML13071A059

Stephen Spencer STP-15 DOI Office of the Secretary ML13058A027

Each comment has a comment ID consisting of two numbers separated by a hyphen. The part 

of the comment ID before the hyphen is the Commenter ID. The part of the comment ID after 

the hyphen is the comment number, which refers to the sequential comment given by the 

commenter. For example, comment xx-yy is the yy comment from the Commenter xx. 

In response to the comments, the staff did not identify any new and significant information 

provided on Category 1 issues or information that required further evaluation of Category 2 

issues. Therefore, the conclusions in the GEIS and draft SEIS remained valid and bounding, 

and no further evaluation was performed.

The following sections present the comments, or summaries of the comments, along with the 

NRC responses to them. In response to the issues raised, consistent with 10 CFR 51.91, the 

staff provides explanations of why the comments do not warrant further response, citing 

sources, authorities, or reasons that support the explanation, as appropriate. When comments 

have resulted in modification or supplementation of information presented in the draft SEIS, 

those changes are noted within the NRC response. Changes made to the draft document are 

marked with a change bar (vertical lines) on the side margin of the page. 

Comments are grouped in the following categories and presented in the following order:

• general comments in support of or opposition to STPNOC, nuclear power, or 

license renewal for STP, 

• alternatives to license renewal,

• cumulative impacts,

• socioeconomic impact of STP, 

• water usage,

• human health,
Appendix A

A-22

• postulated accidents,

• terrestrial or aquatic ecology,

• uranium fuel cycle and waste management, 

• license renewal rule,

• tribal consultation,

• noise levels,

• comments beyond the scope of NRC’s environmental review, and 

– emergency preparedness

– safety and aging management of plant systems 

– events at Fukushima Japan 

• text clarification.

A.2.1 General Comments in Support of or Opposition to STPNOC, Nuclear Power, or 

License Renewal for STP 

The original sources for the comments in this category (general) can be found in Section A.3 

and are labeled with the following identifiers: 1-1, 1-2, 3 1, 4-2, and 6-5. These comments are 

extracted from the original sources.

Comment 1-1: The results that were presented are exactly as I anticipated they could be, that 

there were small to minimal impacts of any kind. I think the proof of the pudding is that STP has 

been here for well over 20 years now, and we have an environment that we appreciate and 

admire. 

Comment 1-2: We went through a lot of internal furor [2] years ago over a coal plant, and the 

people who opposed that kept saying we have such a great environment here, we don’t want to 

destroy it. That means STP has not done anything adverse to it, and I don’t think renewal of 

this permit is going to do anything that’s going to change that, so I firmly am in support of the 

findings of this environmental impact study.

Comment 4-2: There are many ways to move forward. The risks of continuing with nuclear 

power are great, and that’s because of the inherent nature of nuclear power. There are 

accidents; there are fires. We’ve just been through that.

Response: 

These comments are general in nature. The comments express general support of or 

opposition to STPNOC, nuclear power, or license renewal of STP. 

The comments provide no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and are not evaluated. No changes have been made to the 

SEIS as a result of these comments. 

Comment 3-1: I’ve been here for 28 years. The entire time I’ve been here, STP has been, 

without a doubt, the lifeblood of this community. I do not know anybody who donates as much 

money to civic purposes, fund raisers. They’re very good about being a part of this community 

with the Chamber.

Buddy Eller is the current chairman of the Chamber of Commerce. He works at STP. Tim 

Powell, the vice president at STP, is the president of the school board here. Bart Brown is the 
Appendix A

A-23

department director of my Sunday School class there where I’m a Sunday School teacher. Tim 

is a Sunday School teacher at First Baptist Church.

The people at STP are not only—do not only just give the money that they give to make this 

community viable, but they give their time. The leadership that we experience because of the 

training that these people have received at STP has made a difference in this community. This 

community is what it is predominantly because of STP and their influence in this community.

Comment 6-5: And then, too, finally, is the fact that STP is, in my view, an excellent corporate 

citizen, always willing to step in, always willing to make the difference, always willing to help, 

and has instilled that in all its employees, that their employees are also involved in the 

community. And they are a vital part of this community that we really appreciate and want to 

see them stay.

Response: 

These comments provided similar or the same input (or data) in comparison to the scoping 

comments (Section A.1.2 of this SEIS), for the staff’s environmental analysis of the 

socioeconomic impacts of STP on local and regional communities. The comments include 

socioeconomic-related items such as education and community services. 

The comments provide no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and are not evaluated. No changes have been made to the 

SEIS as a result of these comments. 

A.2.2 Alternatives to License Renewal 

The original source for the comment in this category (alternatives) can be found in Section A.3 

and is labeled with the following identifier: 4-1. The comment is extracted from the original 

sources.

Comment 4-1: I’m going to speak in opposition to relicensing Units 1 and 2. In fact, the option 

that I think should be pursued is not actually on the list of options. 

I understand the importance of a major industry in this community. I understand the importance 

of jobs, and our organization does as well, and we support that. We want every community in 

Texas to be economically viable and thriving.

But, what I think should be happening, instead of relicensing two nuclear reactors that are set to 

retire in 2027 and 2028, this is the time to plan for a transition, to plan for worker training, to plan 

to move toward cleaner, safer energy for the future.

And with 14 and 15 years to work with, that is a doable goal. It’s also very doable in today’s 

world to replace the energy with renewables combined with energy efficiency, and that can be 

backed up with natural gas. This is affordable; this is real. Other communities are looking at 

these options. It can be done; it is being done.

For an example, right now wind turbines are booming across Texas. We’ve already had a point 

in time where wind was producing 25 percent and more of the power that was up on the ERCOT 

grid. Nuclear reactors at the time were around 11 percent.

We can do this; we are doing this. Granted, the wind comes in and out. That’s why you 

combine with energy storage, that’s why you do backup. And ERCOT is becoming very expert 

in making these things level out.

What could this do for the community? There could still be jobs, and lots of them, and hopefully 

even more. This could be growth for the community. So, I think the thing to do is to plan.
Appendix A

A-24

Nuclear reactors were used in this country as a bridge between the time when we could get to 

the point where renewables were viable. That day is here; that time is now.

I’m personally using this in my own home. I have solar panels on the roof that do more than I 

ever thought they would. There are days when I can run the whole house and charge an 

electric car, which does most of my daily driving. That’s possible, that’s doable. We’re doing it. 

It’s here today.

Response: 

This comment expresses concern about adequate discussion for various forms of alternative 

energy production (including wind, natural gas, solar) and energy efficiency as alternatives to 

STP license renewal. Consistent with 10 CFR 51.91(a)(1) and 51.91(b), in Chapter 8 of the 

SEIS, the NRC evaluates potential alternatives to license renewal, including energy production 

from wind farms, natural gas-fired power plants, and solar plants, and from energy efficiency 

programs. 

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment. 

A.2.3 Cumulative Impacts

The original source for the comment in this category (cumulative) can be found in Section A.3 

and is labeled with the following identifier: 4-14. The comment is extracted from the original 

sources.

Comment 4-14: Preliminary findings of small to moderate in terms of cumulative impacts, that 

should be none. There’s a serious problem here. If this community was hosting wind energy or 

solar, I don’t think you would be having these same impacts.

Moderate is not acceptable. And it matters to whom? Who is it moderate for? To whom is it 

low? The workers on site? 

Response: 

The staff concluded that the projected incremental impacts associated with continued STP 

operations would be minimal overall (i.e., the impacts are SMALL except for electric shock 

which is SMALL to MODERATE as described in Section 4.8.4). While the projected incremental 

impacts of STP operations during the license renewal term are minimal, in Section 4.12, the 

staff performed analysis of cumulative impacts for STP license renewal. Cumulative impacts 

are the environmental effects associated with STP license renewal that are overlaid or added to 

those associated with other past, present, and reasonably foreseeable future actions (through 

the period of STP extended operation). The staff’s conclusion of SMALL to MODERATE for 

cumulative impacts associated with STP license renewal is based on its review of the 

aggregation of the incremental impacts of STP license renewal when added to the impacts 

associated with the potential construction of two new STP reactor units, neighboring energy 

projects being considered (i.e., White Stallion Energy Center, LCRA–San Antonio Water System 

Project, and Mary Rhodes Pipeline Phase II) and the Brazos Bend State Park, Mad Island 

Marsh Preserve, Mad Island Wildlife Management Area, Big Boggy National Wildlife Refuge, 

and the Texas Prairie Wetland Project; as well as continued urbanization and habitat 

fragmentation.

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment. 
Appendix A

A-25

A.2.4 Socioeconomic Impact of STP

The original sources for the comments in this category (socioeconomic) can be found in Section 

A.3 and are labeled with the following identifiers: 2-1, 4-13, 5-4, 6-2, 10-2, and 11-1. These 

comments are extracted from the original sources.

Comment 2-1: STP is the largest employer in Matagorda County, with approximately 

1,200 employees.

STP’s license renewal will provide jobs for our children and build a strong, stable economic 

base for our community.

In my two terms on council, I’ve had the opportunity to serve with several employees. These 

people donate their time, their talents to make a difference in our community.

We trust the employees of STP; they’re experts at engineering, operations, maintenance, and 

the environment. They are our neighbors, they are our friends.

Thank you for being here. Thank you for consideration of the license renewal.

Response: 

This comment provides similar or the same input (or data) in comparison to the scoping 

comments (Section A.1.2 of this SEIS), for the staff’s environmental analysis of the 

socioeconomic impacts of STP on local and regional communities. The comments include 

socioeconomic related items such as employment and community services. 

The comments provide no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and are not evaluated. No changes have been made to the 

SEIS as a result of these comments. 

Comment 4-13: There are questions about the impacts of when the reactor is down. It 

becomes expensive. With the 16 percent ownership of Austin Energy, the months that they 

were down, roughly from November till almost April of 2012—November 2011 to almost April, 

that cost Austin 42 million, and so I think it’s increasingly expensive as we have these outages. 

These reactors have been part of the year-long outages in years past.

Comment 5-4: STPNOC’s only objective is to make money for their owners. The appearance 

and grand gestures toward community and safety are an important part of that process, but the 

actual implementation of the same is counterproductive to the process of making money.

For example, STP has long been a top producer in the nuclear industry in both profit and output; 

however, when forced outages in Unit 2 caused the profitability to fall, the new management 

sent nearly 300 people, 25 percent of STP’s workforce, home without pay days before 

Thanksgiving, and they were unpaid through the end of the year. 

Where was the professed concern for family and employees and community then? Taking a 

backseat to profit, as they always will, and even more so as the plant ages and reasonable 

maintenance is neglected in the interest of cost savings.

Today’s corporate world demands lean, efficient operation. A process of trial and error 

establishes how lean a company can be and still profit. The workforce is ever more and more 

comprised of contract workers with lower wages and no benefits. 

One might argue that’s just business, and I completely agree. However, framed by the reason 

that we are here, to discuss STP’s environmental impact, including the socioeconomic 

indicators, on our community, we must consider all the factors fully and realistically in the final 

[S]EIS. 
Appendix A

A-26

Comment 6-2: And with that, I think that’s the second point, is the efficiency, that we do have 

an excellent run plant. As my predecessor made the comment just a moment ago about what 

happened with the contract workers, we are in a unique situation where STP is, because of the 

price of natural gas, losing money, and as in any household, if you spend more than you make, 

you go under, so there’s that need to conserve resources.

Comment 10-2: The expense of old, aging nuclear reactors is too costly to maintain, especially 

when the marketplace shows clear signs of embracing renewable generation sources and 

energy efficiency technologies. If the reactors manage to function until 2027, fine. At that time, 

they should be replaced with what’s new and affordable in the energy market. Committing to 

extending their licenses now is not fiscally responsible.

Comment 11-1: The expense of old, aging nuclear reactors is too costly to maintain, especially 

when the marketplace shows clear signs of embracing renewable generation sources and 

energy efficiency technologies. If the reactors manage to function until 2027, fine. At that time 

they should be replaced with what’s new and affordable in the energy market. Committing to 

extending their licenses now is not fiscally responsible.

Response: 

These comments raised concerns about the operational economy (i.e., operational efficiency, 

viability, and profitability) of STP. The NRC has no role in the operational economy of STP, 

except for the STP capability to comply with NRC requirements for protecting the public safety, 

security, and the environment. Furthermore, the NRC has long considered that determination of 

the economic viability of continuing the operation of a nuclear power plant is an issue that 

should be left to appropriate energy-planning decisionmakers (State regulatory and utility 

officials). 

The comments provide no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and are not evaluated. No changes have been made to the 

SEIS as a result of these comments. 

A.2.5 Water Usage

The original sources for the comments in this category (hydrology) can be found in Section A.3 

and are labeled with the following identifiers: 4-6 and 5-2. These comments are extracted from 

the original sources.

Comment 4-6: You’ve already got the factor that the huge amount of water being used to cool 

these reactors means less freshwater can reach the Gulf of Mexico; less blue crabs. That 

impacts birds.

Comment 5-2: Another aspect of the [S]EIS I think is understated and not given serious weight: 

the serious water shortage facing our region. To assign a small impact valuation to a shortage 

of life-giving necessity is irresponsible. In what will undoubtedly be a new drought of record, this 

is premature and presumptuous.

Response: 

Surface water and aquatic resources at STP, and the effects of plant operations on surface 

water hydrology and aquatic resources, are presented in Sections 2.2.4, 2.2.6, 4.3, and 4.5 of 

this SEIS, respectively. STP surface water usage, water rights, and surface water withdrawal 

restrictions imposed on plant operations are specifically discussed in Sections 2.1.7.1 and 4.3.2. 

In the State of Texas, water use is heavily regulated through an appropriation process. As 

discussed in Section 4.3.2, STP is limited to withdrawing 55 percent of the river flow that 
Appendix A

A-27

exceeds 300 cubic feet per second or 135,000 gallons per minute. In other words, STPNOC is 

limited in its ability to withdraw water from the Colorado River during low flow conditions. This 

limitation is designed to ensure flow for downstream uses including protection of freshwater 

inflows to Matagorda Bay during low flow conditions. In support of statewide water planning, 

regional water supply planning, encompassing the region in which STP is located, is performed 

by the Lower Colorado Regional Water Planning Group, which accounts for STP surface water 

withdrawals and consumptive uses along with those of other appropriated uses. While the 

Lower Colorado Regional Water Planning Group has projected potential surface water 

shortages in the coming decades based on a set of conservative assumptions, it has identified 

strategies to address such shortages using a variety of strategies even under conditions similar 

to the drought of record. Based on the regional planning data and consideration of STP surface 

water withdrawals, the staff concluded that the impact on surface water resources, including 

associated instream (aquatic) ecological communities and downstream water availability, in the 

lower Colorado River from continued withdrawals during the license renewal term would be 

SMALL. 

The comments provide no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and are not evaluated. No changes have been made to the 

SEIS as a result of these comments. 

A.2.6 Human Health 

The original sources for the comments in this category (human health) can be found in Section 

A.3 and are labeled with the following identifiers: 4-5, 4-7, 4-9, 4-15, 4-17, and 14-5. These 

comments are extracted from the original sources.

Comment 4-5: I’m concerned about at the plant—and I think there needs to be further look at 

tritium. There are tritium problems at the site. There’s monitoring wells that show that.

When you combine that with the fact that the bottom of the main cooling reservoir has some 

leakage going on—this is documented; this was in the application for South Texas Project 3 and 

4—okay, where is the research? Where is that tritium going? Is it going out the bottom of the 

cooling reservoir and going into the Gulf of Mexico?

Is it going into fish? Is it going into the food chain? Is it impacting animals that feed upon these 

species? Could it be a factor impacting whooping cranes, which are endangered? 

Nobody has looked at this, and it needs to be looked at. This is part of the environmental 

impact assessment.

Comment 4-7: But in addition to that, we need to be looking at, at this point in time, whether the 

radiation is getting into these species; not just the numbers of fish. There needs to be additional 

analysis.

Comment 4-9: Now, in 2003 there was leakage of radioactive material outside the reactor, at 

the base of it. That’s not where radioactive material’s supposed to be, ever.

And I remember when these reactors got built. We were told there was a backup system and 

then another backup system and then another. In fact, there were 12—there used to be 

12 backup systems, and radioactivity would never escape, and yet it did. It has, within this 

operating lifetime.

We still have quite a ways to go before the retirement dates of these reactors, and we’ve got 

these problems.
Appendix A

A-28

Comment 4-17: And even though there’s been luck so far, I have great concerns, as do many 

others who are not here tonight—and I’ll go ahead and say that I’m speaking for many other 

people as well—that while we have so far no major accident at the site, there needs to be 

research in the amount of radiation, radionuclides migrating off the site.

Response: 

The staff reviewed STP’s radioactive effluent monitoring and radiological environmental 

monitoring programs for potential impacts to the environment (i.e., human beings, aquatic and 

terrestrial biota) in Section 4.8. The staff concluded that STP’s radioactive effluent monitoring 

and radiological environmental monitoring programs would be effective in controlling the 

radiological impacts to the workers, the public, and the environment within the radiation 

protection limits and standards of the NRC and the EPA. These radiological programs are 

ongoing programs that are performed throughout the licensed operation of STP and are subject 

to periodic NRC inspection for compliance with regulatory standards. For these reasons, the 

impacts to the environment are SMALL. 

In addition, in Section 4.11 of this SEIS, the staff provided a discussion of a new generic issue, 

“Exposure of aquatic organisms to radionuclides.” This is a new issue evaluated by the NRC in 

its revised license renewal GEIS. This new issue considers the impacts to aquatic organisms 

from exposure to radioactive effluents discharged from a nuclear power plant during the license 

renewal term. The GEIS generically concludes that the impacts to aquatic organisms are 

SMALL for all nuclear power plants when radioactive effluent discharges are maintained within 

NRC requirements. 

In addition, the staff’s evaluation of groundwater resources at STP, and the effects of plant 

operations on groundwater quality, are presented in Sections 2.2.5.2 and 4.4.3 of the SEIS. 

Specifically, Section 2.2.5.2 summarizes the results of the staff’s review of STPNOC’s 

Groundwater Protection Program for STP, including the placement of site groundwater 

monitoring wells. As part of this evaluation, the staff specifically reviewed the hydrogeologic 

investigation prepared for STP in 2009 and the results of ongoing groundwater quality 

monitoring.

As detailed in Section 4.4.3, the staff’s review of data pertaining to seepage from the MCR and 

the releases of liquids containing tritium within the protected area of STP, Units 1 and 2, found 

that releases have not altered current groundwater use in the region downgradient of the STP 

site. No migration of tritium in groundwater in excess of the EPA’s drinking water standard is 

occurring or is projected to occur. The staff further concluded that groundwater-quality impacts 

would remain SMALL during the license renewal term. 

The comments provide no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and are not evaluated. No changes have been made to the 

SEIS as a result of these comments.

Comment 4-15: I’m concerned about the fact that as contract employees get laid off, as some 

of the existing workers are impacted in the world of job cuts, that safety is taking a backseat to 

economics and trying to shave costs.

That means workers on the site have to work longer hours, have to work more, and potentially 

are exposed to more radioactivity. That is of great concern, and these things need to be 

addressed in the environmental impact statement.

And so for a worker, that impact might not be moderate; that impact might be huge. It depends 

on who we’re talking about.
Appendix A

A-29

Response: 

The NRC’s mission is to ensure adequate protection of plant workers, members of the public, 

and the environment from the impacts of radiation from the operation of nuclear power reactors. 

The NRC does this by establishing regulatory dose limits for radiological protection. The limits 

are set to protect workers and the public from the harmful health effects of radiation. The limits 

are based on the recommendations of standards-setting organizations. Radiation standards 

reflect extensive scientific study by national and international organizations. The NRC actively 

participates and monitors the work of these organizations to keep current on the latest trends in 

radiation protection.

To ensure that nuclear power plants are operated safely, the NRC licenses the plants to 

operate, licenses the plant operators, and establishes license conditions for the safe operation 

of each plant. The NRC provides continuous oversight of each plant under the NRC’s 

inspection and enforcement programs. The NRC’s reactor oversight process integrates the 

NRC’s inspection, assessment, and enforcement programs. The operating reactor assessment 

program evaluates the overall safety performance of operating commercial nuclear reactors and 

communicates those results to applicant management, members of the public, and other 

government agencies. The assessment program collects information from inspections and 

performance indicators in order to enable the NRC to arrive at objective conclusions about an 

applicant’s safety performance. Based on this assessment information, the NRC determines 

the appropriate level of agency response, including supplemental inspection and pertinent 

regulatory actions ranging from management meetings up to and including orders for plant 

shutdown. The NRC conducts follow-up actions, as applicable, to ensure that the corrective 

actions designed to address performance weaknesses were effective.

While the NRC maintains regulatory oversight of STP, it is the responsibility of STPNOC’s 

management to ensure that plant operation complies with NRC requirements, including the 

radiation protection requirements in 10 CFR Part 20, “Standards for Protection Against 

Radiation,” at all times. Changes in staffing levels do not alter STPNOC’s requirement to 

comply with NRC regulations.

In Table 4-15 in Section 4.8 of this SEIS, the staff identifies “occupational radiation exposures” 

as an issue it reviewed for STP. As stated in Section 4.8, the staff did not identify any 

potentially new and significant information regarding STPNOC’s Radiation Protection Program 

that would prevent STPNOC from providing adequate protection to its workers. Therefore, the 

impacts are within the bounds of those discussed in the GEIS—that the projected maximum 

occupational doses during the license renewal term are within the range of doses experienced 

during normal operations and normal maintenance outages and would be well below regulatory 

limits.

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment.

Comment 14-5: This section describes the STP Radiological Environmental Monitoring 

Program (REMP) and states that reports were reviewed and no adverse radiological trends 

were observed. It also stated the data showed there was no measurable impact to the 

environment from operations at STP.

• Include, or incorporate by reference, a synopsis of the data, methods, and 

analysis used to determine that no adverse trends or no measurable impact 

to the environment would occur from STP operations in the Final EIS.
Appendix A

A-30

Response: 

For license renewal, the NRC performed a comprehensive evaluation of all nuclear power plants 

in the U.S. to assess the scope and impact to public health and safety and the environment from 

radioactive material released from a nuclear power plant for an additional 20 years of operation. 

The impact evaluation performed by the staff and presented in the Generic Environmental 

Impact Statement for License Renewal of Nuclear Plants (NUREG 1437 (GEIS)) identified 

92 environmental issues that were considered for the license renewal evaluation for power 

reactors in the U.S. The industry, Federal, state, and local governmental agencies, members of 

the public, and citizen groups commented on and helped identify these 92 issues during the 

preparation of the GEIS. For each of the identified 92 issues, the staff evaluated existing data 

from all operating power plants throughout the U.S. From this evaluation, the staff determined 

which issues could be considered generically and which issues need to be considered on a site 

specific basis. The GEIS divides the 92 issues that were assessed into two principal 

categories—one for generic issues (which are termed “Category 1 issues”) and the other for 

site-specific issues (termed “Category 2 issues”).

Category 1 (generic) issues are those that meet all of the following criteria:

• The environmental impacts associated with the issue have been determined 

to apply either to all plants or, for some issues, to plants having a specific 

type of cooling system or other specified plant or site characteristic.

• A single significance level (i.e., SMALL, MODERATE, or LARGE) has been 

assigned to the impacts (except for collective offsite radiological impacts from 

the fuel cycle and from high-level waste and spent fuel disposal) for all plants.

• Mitigation of adverse impacts associated with the issue has been considered 

in the analyses, and it has been determined that additional plant-specific 

mitigation measures are “not likely” to be sufficiently beneficial to warrant 

implementation.

Category 1 issues are termed “generic” issues because the conclusions related to their 

environmental impacts were found to be common to all plants (or, in some cases, to plants 

having specific characteristics such as a particular type of cooling system). For Category 1 

issues, a single level of significance was common to all plants, mitigation was considered, and 

the NRC determined that it was “not likely” to be beneficial. Issues that were resolved 

generically are not re-evaluated in the SEIS because the conclusions reached would be the 

same as in the GEIS, unless new and significant information is identified that would lead the 

NRC staff to re-evaluate the GEIS’s conclusions. During the environmental reviews of license 

renewal applications, the NRC staff makes a concerted effort to determine whether any new and 

significant information exists that would change the generic conclusions for Category 1 issues. 

Radiological issues—radiological impacts on human health and radiation doses to members of 

the public from the current operation of nuclear power facilities—were examined from a variety 

of perspectives, and the impacts were found to be well within NRC’s and EPA’s radiation 

protection standards in each instance. As a result, the issues are classified as Category 1 

issues.

Category 2 issues are those that require a site-specific review. For each of the Category 2 

issues applicable to the site under review, the staff evaluates site-specific data provided by the 

applicant, other Federal agencies, state agencies, tribal and local governments, as well as 

information from the open literature and members of the public. From this data, the staff makes 

a site-specific evaluation of the particular issues and presents its analyses and conclusions in 

the SEIS for the facility.
Appendix A

A-31

This does not mean that the NRC takes the generic (Category 1) issues “off the table” for public 

review. If there is new and significant information that would change the conclusions reached in 

the GEIS, the issue requires a site-specific analysis. During the scoping process and the 

environmental review, the NRC looks for any information that could demonstrate that there are 

unique characteristics related to the facility or the environment surrounding the facility that 

would lead to the conclusion that the generic determination for a particular issue is not valid for 

a specific site. The NRC staff discusses and evaluates the potential new and significant 

information relative to impacts of operations during the renewal term in the SEIS.

The NRC expects its applicants to continue to comply with its radiation protection standards 

during the period of license renewal; therefore, there is no reason to expect radioactive effluents 

to increase during the period of the renewal license. However, as with all Category 1 

conclusions, the NRC staff review evaluates each license renewal application and the site to 

determine if there is new and significant information that would change the conclusion in the 

GEIS. In addition, the staff notes that effective use of radioactive waste treatment systems and 

practices at nuclear power plants have resulted in public radiation dose being well within NRC’s 

ALARA dose criteria contained in Appendix I to 10 CFR Part 50. The NRC staff concluded in 

the GEIS that the significance of radiation exposures to the public attributable to operation after 

license renewal will be small at all sites and that this is a generic (Category 1) issue.

The REMP was evaluated in detail in the GEIS and determined that it is a Category 1 issue. As 

part of the staff’s independent review for new and significant information, the staff reviewed 

STP’s radiological environmental monitoring data and found it to be within the bounds of the 

detailed assessment performed in the GEIS. In addition, the staff reviewed the radiological 

environmental monitoring data reported by the Texas Department of State Health Services 

(DSHS) from its Environmental Monitoring Program. The State concluded that the sample data 

indicated no release of radioactive material to the environment that exceed the regulatory or 

license limits of the DSHS or any other agency such as the NRC or DOE. The staff has also 

evaluated groundwater quality and groundwater protection monitoring at STP and the effects of 

plant operations on groundwater quality, which are presented in Sections 2.2.5.2 and 4.4.3 of 

the SEIS, respectively. The discussion of STPNOC’s REMP is contained in Section 4.8.2 of this 

SEIS. 

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment. 

Comment 14-7: Tritium sample levels at STP, Units 1 and 2, have ranged from 17,000 

picocuries per liter (pCi/L) to less than 7,000 pCi/L. The EPA primary drinking water standard 

for tritium is 20,000 pCi/L. Cumulative impacts to groundwater resources from the increased 

tritium levels produced by the proposed STP, Units 3 and 4, were not discussed.

• Include a detailed description of how the proposed STP, Units 3 and 4, will 

affect tritium levels monitored on or near the STP.

NRC staff concluded that the cumulative impact to groundwater resources as a result of 

relicensing would be small. The building of STP, Units 3 and 4, and the resulting increase in 

tritium levels, are reasonably foreseeable future actions, which should be included in the 

cumulative impacts to groundwater resources section. The analysis of cumulative tritium levels 

for Units 3 and 4 may warrant a designation of cumulative impacts as moderate.

• Analyze the expected cumulative tritium levels as a result of Units 3 and 4 

being built and the effect this would have on groundwater resources. After 
Appendix A

A-32

factoring in the impacts from Units 3 and 4; determine if the cumulative 

impacts are small or moderate.

Response: 

As discussed in the GEIS, the REMP was evaluated in detail and determined that it is a 

Category 1 issue. As part of the staff’s independent review for new and significant information, 

the staff reviewed STP radiological environmental monitoring data and found it to be within the 

bounds of the detailed assessment performed in the GEIS. Separate from the assessment of 

the impacts of reasonably foreseeable future actions on groundwater use and quality presented 

in Section 4.11.3.2 of the SEIS, the staff performed a radiological cumulative impacts 

assessment, which is included in Section 4.11.6. The analysis in Section 4.11.6 encompasses 

the extended operation of STP, Units 1 and 2, and the projected operation of Units 3 and 4, as 

well as the reasonably foreseeable installation of a dry fuel (used fuel) storage system. The 

staff concluded that STP’s radioactive effluent monitoring and radiological environmental 

monitoring programs would be effective in controlling the radiological impacts to the workers, 

the public, and the environment within the radiation protection limits and standards of the NRC 

and the EPA.

Specific to the monitoring of tritium in the groundwater, the staff’s evaluation of groundwater 

resources at STP, and the effects of plant operations on groundwater quality, are presented in 

Sections 2.2.5.2 and 4.4.3 of the SEIS. Section 2.2.5.2 specifically summarizes the results of 

the staff’s review of STPNOC’s Groundwater Protection Program for STP, including the 

placement of site groundwater monitoring wells. As part of this evaluation, the staff reviewed 

the hydrogeologic investigation prepared for STP in 2009 and the results of ongoing 

groundwater quality monitoring. STP Groundwater Protection Program monitors the 

groundwater for inadvertent leaks or spills of liquids containing radioactive material. As detailed 

in Section 4.4.3, the staff’s review of data pertaining to seepage from the main cooling reservoir 

(MCR), and the releases of liquids containing tritium within the protected area of STP, Units 1 

and 2, found that releases have not altered current groundwater use in the region downgradient 

of the STP site. No migration of tritium in groundwater in excess of the EPA’s drinking water 

standard is occurring or is projected to occur. The staff further concluded that groundwater 

quality impacts would remain SMALL during the license renewal term.

Also, as discussed in Section 4.8.2, STPNOC has a REMP that monitors the environment 

outside the STP site to verify that radioactive material from STP is not building up in the 

environment. STP is required by NRC regulations in 10 CFR Part 20 to limit radiation exposure 

to members of the public from its radioactive effluents (gaseous, liquids, and direct radiation). 

The monitoring programs at STP will alert STP personnel to adverse trends in radiation levels 

onsite and offsite. These radiological programs are ongoing programs that will be performed 

throughout the licensed operation of STP and are subject to periodic NRC inspection for 

compliance with regulatory standards. Since compliance with NRC radiation protection limits is 

required at all times, the NRC expects STPNOC to take appropriate actions to ensure that the 

levels of tritium at STP, Units 1 and 2, as well as for the projected Units 3 and 4 comply with 

NRC limits.

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment.
Appendix A

A-33

A.2.7 Postulated Accidents 

The original source for the comment in this category (postulated accidents) can be found in 

Section A.3 and is labeled with the following identifier: 4-3. The comment is extracted from the 

original source.

Comment 4-3: There’s an increasing amount of fracking, and fracking has been linked to 

earthquakes, and who knows what will be happening over time. I think the environmental 

impact research needs to look further at that question.

Response: 

This comment expresses concerns about the practices of fracking and the need for additional 

research on fracking as it relates to earthquakes. Additional research on fracking is beyond the 

scope of this environmental review for STP license renewal. 

For the purpose of license renewal, the GEIS concludes that environmental impacts associated 

with postulated reactor accidents, including earthquake risks, are SMALL (10 CFR Part 51, 

Subpart A, Appendix B). In Chapter 5 and Appendix F of the SEIS, the staff considers the best 

available information for seismic data from the U.S. Geological Survey (USGS) applicable for 

STP in considering the severe accident mitigation alternatives (consideration of applicable costbeneficial severe accident mitigation measures) and issued RAI to the applicant, as appropriate. 

Based on its review, the staff did not identify any new and significant information that would 

change the GEIS conclusion. 

Regarding an induced earthquake related to hydraulic fracturing, because the earthquakes 

associated with the injection process occur within a few kilometers of the injection wells, the 

region potentially impacted will be limited to the immediate vicinity of the injection activities. 

STP is not located near a shale formation; thus, it is not impacted by fracking. 

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment.

A.2.8 Terrestrial or Aquatic Ecology

The original sources for the comments in this category (ecology) can be found in Section A.3 

and are labeled with the following identifiers: 5-1, 6-4, and 15-1. These comments are 

extracted from the original sources.

Comment 5-1: I have several areas of this [S]EIS that I would like to fundamentally disagree 

with and respectfully ask you to reconsider.

I continually see and hear that STP is lauded as beneficial to local wildlife and habitat, and that 

angle is accepted and incorporated into the [S]EIS. This is not what I see as a local citizen and 

one of only three licensed wildlife rehabilitators here in our county.

I see a large corporation doing a great job of showing you and the public the good and 

beneficial to them part of the picture.

In reality, the contract granted by STP to deal with wildlife issues goes to the lowest bidder, 

currently GCA. GCA, as well as previous environmental contractors, requires its employees to 

destroy bird nests, eggs, and infant birds that nest on the site as part of standard housekeeping.

These employees receive no training in applicable laws such as the Migratory Bird Treaty Act, 

no training on species identification, and [they] don’t even know what kind of avian life they’re 

destroying.
Appendix A

A-34

One year ago this week, STP initiated a nuisance-bird eradication program, whereby seed was 

set out for several days in a row to establish feeding stations on site, and then the seed was 

replaced with poison.

This project was aimed primarily at several protected species of grackles that congregate in 

large numbers to overwinter on the Texas Gulf Coast. The poisons that are used are 

neurotoxic, and the animals that ingest them die a horrible death, often beating themselves to 

death on the ground.

Predator species such as hawks, eagles, and owls are drawn to the activity and, by ingesting 

the tainted birds, they ingest the poisons as well. These are biocumulative in the food chain.

I got calls about several raptors on and around the STP site that week that were acting 

abnormally. One red-tail hawk was brought to my facility but could not be saved.

I e[-]mailed STP authorities before this poisoning took place and asked them to consider other 

options. They did not reply to my e[-]mail, which is attached; I’ll leave my comments here.

There are much more humane ways to keep the site free of unwanted birds, short of killing 

them, though maybe none so inexpensive. These kinds of activities must be considered in the 

scoping process, and we must acknowledge that fact, that profit supersedes environmental 

concerns.

STP also regularly deals with mammals on site with lethal solutions, and when problem animals 

are relocated, employees lack the training to recognize disease, which may be infectious, and 

they are not trained on the laws that pertain especially to our fur-bearing species.

Our wildlife rehabilitation group has offered training to STP personnel at no expense but were 

told—and I quote—“We are not ready to take it to that level.”

Additionally, STP regularly kills entire bee colonies that swarm on site. Honeybee numbers are 

in serious decline, and most of our food crops depend on their pollination.

Response: 

This comment expresses several concerns regarding STPNOC’s onsite wildlife management. 

In response to this comment, the NRC issued a request for additional information (RAI) from 

STPNOC in a letter dated February 15, 2013 (ADAMS No. ML13037A678). STPNOC 

responded to the RAI by letter dated March 6, 2013 (ADAMS No. ML13079A334). In its RAI 

response, STPNOC addressed the comment in full. The remainder of this comment response 

summarizes STPNOC’s RAI response.

The commenter asserts that STPNOC requires its contractors and employees to destroy bird 

nests, eggs, and infant birds that nest on the site. STP site procedure OPGP03-Z0-0025, “Site 

Environmental Compliance,” provides instructions for site workers on wildlife protection and 

control. The purpose of this procedure is to provide guidelines necessary for site compliance 

with applicable nonradiological environmental laws, regulations, procedures, and commitments 

at the South Texas site. This procedure prohibits site personnel (other than the licensed animal 

controllers or those individuals designated by the site Facilities Management Group) from 

engaging in wildlife protection and control measures or taking any action that may cause harm 

to any wildlife found on site. Regarding bird nests, eggs, and young, the procedure states, “No 

site personnel shall disturb, move, or destroy an active bird nest, eggs, or young.” The 

procedure also states, “If young are inadvertently dislodged from a nest or found separated from 

their nest, Facilities Management should be contacted and the young protected if possible until 

arrival of Facilities personnel.”
Appendix A

A-35

The commenter states that contractor employees are not trained in applicable laws such as the 

Migratory Bird Treaty Act (MBTA) or in identification of species protected under such laws. 

STPNOC does not provide employees or contractors specific training on the Endangered 

Species Act, the Migratory Bird Treaty Act, or the Bald and Golden Eagle Protection Act and 

does not provide employees training on identification of protected species that are likely to 

occupy on the South Texas site. However, as noted above, site procedure OPGP03-Z0-0025 

prohibits site personnel from engaging in wildlife protection and control measures or taking any 

action that may cause harm to any wildlife found on site. STPNOC hires or works with licensed 

personnel for onsite wildlife management as needed, including Janak Alligators LLC for 

relocating nuisance alligators and nest stamps; the United States Department of Agriculture 

(USDA) for wildlife damage management under a Non-Commercial Political Pesticide 

Applicators License; Orkin Services for bee eradication under the appropriate permit; and Gulf 

Coast Wildlife Rescue for wildlife rehabilitation.

The commenter discusses a “nuisance bird eradication program” that the commenter asserts 

STPNOC put in place to eradicate several species of protected grackles through neurotoxin 

poisoning. The commenter notes that predator species such as hawks, eagles, and owls may 

eat the poisoned birds, thereby ingesting the neurotoxin. STPNOC does not have such a 

program. However, STPNOC has coordinated with the USDA Wildlife Services for wildlife 

damage management on the site. USDA performs such activities, which include bird 

depredation (control), at STPNOC’s request on an as-needed basis. STPNOC has requested 

these services specifically to control the overpopulation of blackbirds—which could include the 

common grackle (Quiscalus quiscula), a species protected under the MBTA, though not 

Federally or State-listed as threatened or endangered. The MBTA prohibits removal of all listed 

species or their parts from private property, except in circumstances for which the property 

owners have a Federal permit. In cases where the birds pose a health or safety hazard to site 

employees and equipment, USDA performed bird depredation from 2001 through 2005 and then 

again in 2010, 2011, and February 2013. When STPNOC requests such services from the 

USDA, the USDA Animal and Plant Health Service monitor bird activity using a pre-bait to 

determine the number of target and non-target species present in the area and to determine an 

acceptable area for targeting. The USDA then replaces the pre-bait with Starlicide, a chemical 

salt also known as Compound DRC-1339. Starlicide is a slow-acting avicide registered for 

controlling blackbirds, starlings, pigeons, gulls, magpies, and ravens that damage agricultural 

crops or personal property or prey upon Federally designated threatened or endangered 

species. STPNOC also uses Fog ForceTM, which is a bird repellent, during refueling outages, 

when the personnel population onsite is at its maximum. Fog ForceTMis not a poison and, 

therefore, will not affect the food chain for predators. STPNOC has also used various bird 

deterrent measures in the past, including falcons, avian laser dispersal agents, butane cannons, 

deterrent bird spikes, plastic owls, bird screen netting, and prey calls.

The commenter asserts that agents of the applicant regularly kill or relocate mammals on the 

site. As discussed previously, STPNOC has a site procedure that prohibits untrained site 

personnel from engaging in wildlife management activities. STPNOC Facilities Management 

has contracted with licensed animal controllers or individuals to trap and relocate mammals 

found in areas that potentially pose a health or safety threat to site employees or equipment. 

Such activities occur on an as-needed basis.

Finally, the commenter asserts that STPNOC kills bee colonies on the site. The commenter 

suggests that honeybees, specifically, may be targeted. STPNOC has eradicated bee colonies 

in cases where they have been in populated areas that could pose a health and safety threat to 

employees or plant equipment. In these instances, STPNOC Facilities Management contracts a 
Appendix A

A-36

licensed pest controller. Bee colonies in non-populated areas that do not pose a health or 

safety concern are not disturbed. No specific species are targeted.

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment. 

Comment 6-4: I look at the overall impact, county- and area-wide. Every year Matagorda 

County is rated number one in migratory bird population in different species. That tells me, with 

STP having been here for 30 years, that environmentally they have had a minimal, at best, 

impact upon this area. Otherwise we would not see that kind of wildlife still in the region across 

this area.

Response: 

This comment suggests that the high avian species diversity in Matagorda County supports a 

conclusion that STP has had a minimal impact on the environment since it began its operation. 

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment. 

Comment 15-1: Pursuant to Section 7 of the Endangered Species Act (ESA), the U.S. Nuclear 

Regulatory Commission initiated and is currently undergoing informal consultation with the 

U.S. Fish and Wildlife Service regarding [F]ederally listed species:

Threatened

San Marcos salamander (Eurycea nana) 

Piping plover (Charadrius melodus) 

Endangered

Houston toad (Bufo houstonensis) 

Texas blind salamander (Typhlomolge rathbuni) 

Golden-cheeked warbler (Dendroica chrysoparia) 

Northern aplomado falcon (Falco Femoralis septentrionalis) 

Whooping crane (Grus amercana) 

Attwater’s greater prairie-chicken (Tympanuchus cupido attwateri) 

Black-capped vireo (Vireo atricapilla) 

Candidate Species. Candidate species are those being considered for possible listing pursuant 

to the ESA. While these species are not legally protected under the ESA, the FWS provides 

information on these species for consideration in your environmental review process and to 

encourage efforts to avoid adverse impacts to these species. The following candidate 

freshwater mussel species may occur within the project area.

Freshwater mussels

Texas Fatmucket Lampsilis bracteata

Smooth Pimpleback Quadrula houstonensis

Texas Pimpleback Quadrula petrina

Texas Fawnsfoot Truncilla macrodon

The enclosure details best management practices for use during maintenance activities in the 

project area and along transmission corridors to assist in reducing impacts to freshwater 

mussels.

Response: 
Appendix A

A-37

This comment indicates that the NRC and FWS are currently in consultation under Section 7 of 

the Endangered Species Act of 1973, as amended (ESA), for several Federally listed species. 

Section 4.7 of the SEIS discusses Federally listed species and Section 7 consultation. The staff 

has updated this section between publication of the draft SEIS and the final SEIS to reflect the 

current status of consultations.

The comment also provides best management practices that could reduce impacts during 

maintenance activities in the project area and along transmission line corridors. The best 

management practices are applicable to construction activities and maintenance activities that 

cross or potentially affect river, stream, or tributary aquatic habitat. However, the proposed 

license renewal would not involve any construction, refurbishment, or other land-disturbing 

activities. 

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment.

Comment 14-4: After reviewing [F]ederal and [S]tate threatened and endangered species lists, 

a “no effect” determination was made on 31 species, and a “is not likely to adversely affect” 

(NLAA) determination was made on 10 species. A “no effect” determination is appropriate when 

a proposed action will not affect listed species. No further consultation with the [FWS] is 

required if a [F]ederal agency makes a “no effect” determination. A[n] NLAA determination is 

appropriate when a proposed action will have insignificant or beneficial effects to listed species. 

Written concurrence must be obtained from the FWS to satisfy Section 7 consultation 

requirements of the Endangered Species Act for the 10 species where a[n] NLAA determination 

was made.

Obtain written concurrence from [FWS] on the 10 species where a[n] NLAA determination was 

made. Include this concurrence in the Final EIS.

Response: 

The commenter summarizes the NRC staff’s determinations regarding Federally threatened and 

endangered species. The commenter states that written concurrence with the NRC’s 

determination that the proposed action is “not likely to adversely affect” 10 species must be 

obtained from the FWS in accordance with Section 7 of the ESA. The NRC staff requested the 

FWS’s concurrence with its effect determinations in a letter dated December 10, 2012 (ADAMS 

No. ML12285A415). Section 4.7 of the SEIS discusses Federally listed species and Section 7 

consultation. Although closure of informal consultation with FWS is not required for the final 

SEIS, the staff has updated this section of the final SEIS to reflect the current status of 

consultations. Neither a separate biological assessment or a biological opinion has been 

identified as waaranted by the NRC staff or FWS. . 

A.2.9 Uranium Fuel Cycle and Waste Management 

The original sources for the comments in this category (waste) can be found in Section A.3 and 

are labeled with the following identifiers: 7-1, 9-1, 10-4, and 14-8. These comments are 

extracted from the original sources.

Comment 7-1: I suggest that this license proceeding be stopped until such time as the Waste 

Confidence Rulemaking finds in favor of the concept of waste confidence.

Comment 9-1: The U.S. Court of Appeals for the District of Columbia has recently ruled as 

invalid the “waste confidence rule,” which states that it is safe to store radioactive waste onsite 

at power plants for extended periods. Since no reasonable solution to the storage and 
Appendix A

A-38

containment of nuclear waste exists anywhere in the world, it is irresponsible to consider 

producing more of it by relicensing nuclear reactors.

Comment 10-4: The U.S. Court of Appeals for the District of Columbia has recently ruled as 

invalid the “waste confidence rule.”

Response: 

The commenters correctly observe that on June 8, 2012, the U.S. Court of Appeals for the 

District of Columbia vacated the NRC’s Waste Confidence Decision and Rule. The comment is 

incorporated into Chapter 6 of the SEIS. In this chapter, the staff provides the status of this rule.

Comment 14-8: Uranium mining impacts were generally addressed in the GElS for In-Situ 

Leach Uranium Milling Facilities (NUREG-1910). However, potential site[ ]specific impacts were 

not addressed in that document. As was discussed during a conference call with NRC on 

January 9, 2013; these site[ ]specific assessments for [t]ribal consultation and environmental 

justice are initiated for individual mining project licenses. This was not readily apparent from 

reading the [draft] SEIS. 

• We recommend the final [S]EIS clarify the relationship amongst various NRC 

programs and their respective documents and clarify when [t]ribal 

consultations and [environmental justice] assessments are initiated for 

actions.

Long Term Storage of Onsite Nuclear Waste. 

As indicated in the [draft] SEIS, this issue is currently being addressed in an EIS 

to support the update of the Waste Confidence Decision and Rule (WCD). In 

addition, no licenses dependent upon this decision and rule will be issued until 

the WCD EIS has been completed. If the results of the WCD EIS identify 

information that requires a supplement to this EIS, NRC will perform the 

appropriate additional NEPA review for those issues before making a final 

licensing decision. EPA will review the WCD EIS and any appropriate 

supplemental NEPA documentation, as required.

Response: 

The NRC’s environmental review for this SEIS is confined to environmental matters relevant to 

the extended period of operation requested by the applicant. As noted in this comment, the 

NRC conducts separate environmental reviews for uranium mining, as well as other actions 

related to the uranium fuel cycle and reactor operations and construction. Tribal consultation 

and environmental justice assessments are conducted for each review, as appropriate, and 

discussed in each respective environmental review.

The NRC acknowledges that the EIS currently being prepared for the NRC’s Waste Confidence 

Decision and Rule will be reviewed by EPA. Chapter 6 of this final SEIS contains a discussion 

of the NRC’s actions on the Waste Confidence Decision and Rule. 

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment.

A.2.10 License Renewal Rule 

The original sources for the comments in this category (rulemaking or issuance of regulation) 

can be found in Section A.3 and are labeled with the following identifiers: 13-1 and 14-1. These 

comments are extracted from the original sources.
Appendix A

A-39

Comment 13-1: We respectfully recommend that all operating license renewals be reduced 

from [20] to [10]-year limits. Our reasoning is the loss of scientific predictability given the current 

crisis in global change. World scientists have no experience-based strategies to reduce loss of 

life from yet unknown events. This is true worldwide and not just with our neighbors living in 

[STP] areas. Our plea is to ask that the NRC exercise greater caution in relicensing due to loss 

of environmental predictability.

A [10]-year license renewal will at least buy more time for an early warning system and perhaps 

one last chance to avoid the tipping point. We believe shorter licensing will add the extra time 

needed to ensure at least the campfire is extinguished before leaving the nuclear reactor site.

Comment 14-1: The [draft] SEIS states that “If the renewed license is issued, the appropriate 

energy-planning decision makers, along with STPNOC, will ultimately decide if the reactor units 

will continue to operate on factors such as the need for power.” While informative, this 

statement does not explain to the public and Federal agencies the need for the power in regard 

to the region or Nation.

• Include detailed language in the purpose and need statement about why the 

energy created by the facility is needed.

Response: 

In summary, these comments express concern about the adequacy of the license renewal rule. 

These comments are beyond the scope of the NRC’s environmental review. Comment 

petitioning to issue, amend, or rescind the license renewal rule is governed by 10 CFR 2.802, 

“Petition for Rulemaking,” and is beyond the scope of this environmental review for STP license 

renewal. 

The comments provide no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and are not evaluated. No changes have been made to the 

SEIS as a result of these comments.

A.2.11 Tribal Consultation

Comment 14-9: The [U.S.] has a unique legal relationship with Federally recognized tribes 

based on the Constitution, treaties, statutes, Executive Orders, and court decisions. This 

relationship includes recognition of the right of tribes as sovereign governments to selfdetermination, and an acknowledgment of the Federal Government’s trust responsibility to 

tribes. The precise nature of this relationship will vary depending upon the identity of the tribes, 

nature of trust resources, and Federal agencies involved.

The [draft] SEIS indicates that tribes were identified and contacted for the limited purpose of 

discussing the National Historic Preservation Act, but [it] does not provide complete information 

to determine if [t]ribal officials have been contacted for government-to-government consultation 

on the full scope of potential effects of the [STP] under Executive Order (EO) 13175. It appears 

that the proposed project could affect tribal resources and citizens or government services. 

EPA recommends NRC take the following actions to satisfy consultation with tribes under EO 

13175:

• identify all potentially affected tribes and tribal resources,

• identify potentially applicable treaties, laws, policies, legal responsibilities and 

duties, and

• contact and, as appropriate, initiate consultation with tribes concerning the 

potential effects of its action.
Appendix A

A-40

Response: 

In accordance with the NRC’s National Environmental Policy Act (NEPA) implementing 

regulation (10 CFR Part 51), as well as the spirit of EO 13175, the NRC staff identified and 

initiated dialogue with 10 Federally recognized Native American tribal governments that have 

historic ties to the region surrounding STP or would be potentially affected by continued 

operation of STP or both. Because the NRC has chosen to comply with National Historic 

Preservation Act (NHPA) through incorporation of NHPA Section 106 requirements in its NEPA 

review (per 36 CFR Part 800), tribes were invited to participate in the identification and possible 

decisions concerning historic properties, as well as invited to provide input to other areas of 

environmental review such as terrestrial ecology, aquatic ecology, hydrology, cultural resources, 

and socioeconomic issues (among others). Four tribes responded to the NRC with scoping 

comments ranging from concerns with potential accidents, requests to resurvey the STP site, 

requests for notification if historic and cultural resources of cultural significance were discovered 

on the STP site, and statements of no concern with the undertaking. The NRC responded to 

the tribes in October 2011 and has taken the comments into consideration while preparing this 

SEIS. This correspondence can be found in Appendix D, and a summary of these actions can 

be found in Section 4.9.6. Consequently, dialogue with, and comments from, Federally 

recognized tribes have been considered during the draft period of this SEIS. 

A.2.12 Noise Levels

Comment 14-3: Page 2-62 states noise from STP operations sometimes exceeds 55 A 

weighted decibels (dBA) and can be detected off site. This noise level has been identified as 

causing annoyance with outdoor activities; while a level of 45 dBA can have undesirable effects 

to indoor activities. 

• It is unclear if this information is based on a study of STP noise and how it 

affects the surrounding area or if the noise levels cited are those typical of 

industrial operations similar to STP. Please clarify whether the noise level 

was derived from a site specific study of the STP or [if] the noise level given 

as an example of those that would typify industrial operations similar to STP. 

Also, clarify if 55 dBA is the level of noise detected at the STP, the property 

line, or nearby sensitive noise receptors.

Response: 

The noise levels cited on page 2-62 of the draft SEIS are typical of industrial operations and are 

given as an example of those that would typify industrial operations similar to STP. Given the 

industrial nature of most nuclear power plants, loud noises can be heard offsite. Sources of 

noise vary, but include the sound of turbines, large pump motors, and other industrial machines 

and equipment.

Noise is a Category 1 environmental impact (NEPA) issue (see Table B–1 in Appendix B to 

Subpart A of 10 CFR Part 51, “Environmental Effect of Renewing the Operating License of A 

Nuclear Power Plant”) that has been generically resolved in the 1996 GEIS for license renewal. 

The environmental review for the license renewal GEIS found that noise has not been a 

problem at existing operating nuclear power plants, and, since power plant operations are not 

expected to change during the license renewal term, noise conditions also would not change at 

any nuclear power plant. Based on a review of the STP Environmental Report, scoping 

comments, other available information, and site information visit, the NRC did not identify any 

new and significant information about noise at STP that would change the conclusions 

presented in the license renewal GEIS. STPNOC also reported that there have been no noise 
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A-41

complaints. Noise levels during the period of extended operation are, therefore, expected to 

remain unchanged from what is currently being experienced. There would also be no new noise

sources or increase in noise levels, either in frequency distribution or in intensity.

The comment provides no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and is not evaluated. No changes have been made to the 

SEIS as a result of this comment. 

A.2.13 Comments Beyond the Scope of NRC’s Environmental Review

The original sources for the comments in this category (emergency, safety, or Fukushima) can 

be found in Section A.3 and are labeled with the following identifiers: 4-4, 4-8, 4-10, 4-11, 4-12, 

4-16, 4-18, 5-3, 6-1, 8-1, 10-1, 10-3, and 11-2. These comments are extracted from the original 

sources. 

In summary, these comment express concerns about plant security, emergency preparedness, 

safety, and plant aging. These comments are beyond the scope of the license renewal 

environmental review. As discussed during the scoping public meeting of March 2, 2011, the 

NRC addresses plant performance as part of the ongoing regulatory oversight provided for all 

currently operating power reactors. Therefore, the NRC does not re-evaluate them as part of 

the license renewal review, in accordance with 10 CFR 54.29, “Standard for issuance of a 

renewed license,” and 10 CFR 54.30, “Matter not subject to a renewal review.” Furthermore, 

the aging management of structures and components within the scope of the license renewal 

safety review will be addressed in the staff’s safety evaluation report, separately from the 

environmental review.

Emergency Preparedness

Comment 4-12: And it’s good that it appears that no radioactivity got released, but what if this 

fire was bigger? What if it was elsewhere? What if circumstances had somehow been 

different?

It concerns me that reactors are operating in a community that, after all of these years, still has 

no paid professional fire department. I’m sure the volunteers are very good people and 

probably trained, but if you’ve got nuclear reactor in your backyard, that means that there should 

be a paid professional fire department that can be called on.

Furthermore, I think everyone should be asking the question, if this was a very large fire, 

extensive, how long would it take to get backup fire departments here; for example, from 

Houston?—because I have a feeling that it’s longer than just the drive to get here. 

These are serious safety concerns.

Response: 

These comments express concerns regarding emergency preparedness in the unlikely event of 

a reactor accident at STP. As stated during the scoping public meeting of March 2, 2011, 

comments concerning emergency preparedness are beyond the scope of license renewal 

environmental review. This is because this subject is under the NRC’s review as a part of the 

oversight of the current licensing basis. The NRC addresses these areas of performance as 

part of the ongoing regulatory oversight, including during the STP period of extended operation 

if the licenses are renewed. 

Over the years, the combined efforts of the NRC, Federal Emergency Management Agency 

(FEMA), STPNOC, Texas State and local officials, as well as thousands of volunteers and local 

first responders (such as police, firefighters, and medical response personnel), have produced 
Appendix A

A-42

comprehensive emergency preparedness programs that assure the adequate protection of the 

public in the event of a radiological emergency at STP. The emergency preparedness planning 

incorporates the means to rapidly identify, evaluate, and react to a wide spectrum of emergency 

conditions. Emergency plans are dynamic and are routinely reviewed and updated to reflect an 

ever changing environment during the operation of STP, including during the period of extended 

operation if the STP licenses are renewed. 

The Commission considered the need for a review of emergency planning issues during its 

license renewal rulemaking proceedings on 10 CFR Part 54, which included public notice and 

comment. As discussed in the Statement of Consideration for this rulemaking (56 FR 64966), 

the programs for emergency preparedness apply to all nuclear power facilities. Requirements 

for emergency planning are in the regulations at 10 CFR 50.47 and Appendix E to 10 CFR Part 

50. Through its standards and required exercises, the Commission reviews existing emergency 

preparedness plans throughout the life of STP, keeping up with changing demographics and 

other site-related factors. Therefore, the Commission determination at the time of the rule 

change was that emergency planning was adequately considered on an ongoing basis and did 

not need to be part of license renewal.

The most recent emergency drill for STP occurred on May 9, 2012. The results of the STP drill 

are published in a FEMA report and are viewable at the following Web site:

http://www.nrc.gov/about-nrc/emerg-preparedness/related-information/fema-after-actionreports.html

These comments do not provide new and significant information for this environmental review, 

and these are not evaluated further in the development of the SEIS.

Safety and Aging Management of Plant Systems 

Comment 4-8: There have been problems with this reactor over the years, and they seem to be 

increasing. While we read about great safety reports and great numbers of days without 

shutting down, well, that’s good, and great worker safety; that’s what the reports say.

But when you look across the country—there’s an expert by the name of David Lochbaum; he 

has worked for the NRC; he’s also worked for the Union of Concerned Scientists, and he did a 

report called The Nuclear Tightrope.

And he looked at plants where they had year-long outages. What he found was a typical 

pattern, that in a reactor that had a serious accident, serious problem, there would be glowing 

reports, right up until the accident happened. Nothing was wrong, everything was perfect, and 

then all of a sudden, catastrophic problem that had been missed all along that just wasn’t 

showing up. And then we had this major problem.

So this has happened over and over, and I think it’s time for this report—and for the NRC in 

general—to look deeply into what’s going on.

Comment 4-10: Recently, there have been problems with the control rods getting stuck, not 

being able to function properly. We had an outage just last week that involved that, control rods 

dropping when they’re not supposed to.

That is unsafe. That means that we don’t have full control of this reactor. I’m concerned. I 

personally live in Austin, Texas, and Austin is an owner of this reactor. I’m happy that we get 

some power from it, but I’m very concerned about this safety aspect, for the people who live 

here, for people downwind and around the state.

Comment 4-11: Metal fatigue increases as reactors age. The most dangerous years are the 

early startup years and the final years of a reactor. So, to consider giving a nuclear reactor 
Appendix A

A-43

20 more years of time to operate 14 and 15 years ahead of time, to me this is like telling 

somebody you’re going to sell them a used car, but you’re going to sell it to them today, and 

they’re going to receive it 14 and 15 years later. That doesn’t make sense.

This decision is being looked at and this meeting is being held way, way too early. This is 

wrong timing, and it needs to hold, it needs to wait.

Short of declaring that it’s time to look at transition away, I would urge you to do no action for 

now and to delay until we know more. With the current problems with the reactor, with the 

current fire, that needs to be fully investigated. 

Comment 4-16: And I wish I could say that I shared the opinion of transparency for [STP]. I find 

it to be of concern that information is not more forthcoming.

And in terms of safety, I’m very concerned about the cutting of employees. I think that’s a way 

to increase safety risks.

Comment 4-18: And, also, we need to prepare, because historically at some of the sites that 

were touted as being the safest, the most productive, the ones that were running beautifully, 

that is exactly where the major problems have occurred in U.S. nuclear history.

And, I think we should be looking carefully. I think we should be more forthcoming with 

information, digging into recent events such as the fire that occurred; digging deeper on many 

issues and looking more closely.

Comment 5-3: As time goes on and more and more equipment ages and fails, safety and 

concern for community must be sacrificed if shareholders are to be kept satisfied.

Comment 6-1: One is that what I have observed and seen and heard is that STP has an

excellent safety record. It seeks to be transparent; it seeks to let people know when things are 

going on and seeks to be proactive, from my point of view.

I believe, from my point of view, that STP has the safety of everyone at stake and is one of the 

best-run plants as far as safety and energy in the U.S.

Comment 6-3: Also, I cannot comment about what my predecessor has said about the 

environment on plant site. However, I know that with safety being what it is and the need for 

safety, they are taking that as the most important course.

Comment 8-1: These nuclear reactors are old, and continued incidents like the recent fire on 

January 8th should make them come under more scrutiny. These reactors should not get an 

automatic 20 year renewal. They should in fact [be] made to go into planned retirement as they 

pose too many risks to human life and health to the surrounding community.

Comment 10-1: I am commenting on the proposed relicensing of Units 1 [and] 2 at the [STP] 

Docket ID NRC-2010-0375. These reactors should not be relicensed at this time because of the 

following concern.

Units 1 [and] 2, which are 24 and 25 years old, are licensed to run for 40 years—until 2027–28. 

We should wait 14 years until 2027 and determine what shape they are in at that time before 

considering relicense. Already the reactors are showing signs of age that should concern 

anyone wishing to avoid accidents at nuclear power plants:

• fire in the reactor 2 main transformer on Jan[uary] 8, 2013,

• replacement of the control rod drive mechanisms in both reactors deviate 

from standard measurements sufficiently that many of them are permanently 

stuck and unusable, and 
Appendix A

A-44

• Unit 2 was off-line for 5 winter months, indicating it is no longer reliable.

Comment 10-3: The [STP] is on a list of nuclear plants with a high risk of flooding-related 

failures. A leaked July 2011 [NRC] report labeled “not for public release” deals with flood risk to 

plants across the country if dams break upstream. The very fact that the agency charged with 

regulating nuclear plants would label a report of significant import to the public it serves as “not 

for public release,” shows that agency as not a reliable one to decide relicensing issues. Since 

the STP is considered at risk for flooding, it should not be relicensed at this time.

Comment 11-2: The [STP] is on a list of nuclear plants with a high risk of flooding-related 

failures. A leaked July 2011 [NRC] report labeled “not for public release” deals with flood risk to 

plants across the country if dams break upstream. The very fact that the agency charged with 

regulating nuclear plants would label a report of significant import[ant] to the public it serves as 

“not for public release,” shows that agency as not a reliable one to decide relicensing issues. 

Since the STP is considered at risk for flooding, it should not be relicensed at this time.

Response: 

These comments express concerns about the safety issues or aging management of STP plant 

systems or both. These comments are beyond the scope of license renewal environmental 

review. This is because this subject is under the NRC’s review as a part of the oversight of the 

current licensing basis. The NRC addresses these areas of performance as part of the ongoing 

regulatory oversight, including during the STP period of extended operation if the licenses are 

renewed. In addition, the aging management of structures and components within the scope of 

the license renewal safety review will be addressed in the staff’s safety evaluation report for 

STP. This is separate from the environmental review which focuses on the environmental 

impacts of license renewal. The comments have been provided to the license renewal safety 

review team for consideration in the development of the SER as appropriate. 

In the safety review, the staff examines STPNOC’s programs and processes designed to 

manage the effects of structures and components aging and to ensure adequate protection of 

the public’s health and safety during the 20-year license renewal period. This may result in 

additional aging management measures as necessary.

The comments provide no new and significant information for this environmental review (as 

specified in 10 CFR 51.95(c)(3)) and are not evaluated. No changes have been made to the 

SEIS as a result of these comments.

Events at Fukushima Japan 

The original source for this comment in this category (Fukushima) can be found in Section A.3 

and is labeled with the following identifier: 4-4. This comment is extracted from the original 

sources.

Comment 4-4: In the case of Fukushima, reactor number 1 had been set to retire [1] month 

before the accident there, which, you know, involved their diesel generators, to large extent, as 

well as tsunami and earthquake.

So, if that plant had been shut down as it should have been—they were given 10 more years, 

not 20, like we’re looking at in this case—then that would be one less reactor that had a 

meltdown. And, the whole world is feeling the impacts of that disaster in many different ways, 

including radiation that travels around the globe and impacts fisheries, it impacts products and 

workers’ lives and people who live in Japan, as well as in the U.S. it’s been measured. This 

radiation does reach the U.S.

Response: 
Appendix A

A-45

This comment expresses concerns about the safety issues and aging management of STP plant 

systems in comparison to the accident at Fukushima, Japan. The aging management of STP 

structures and components within the scope of the license renewal safety review is addressed 

in the staff’s safety evaluation report (SER) for STP. This is separate from the environmental 

review, which focuses on the environmental impacts of license renewal. The comments have 

been provided to the license renewal safety review team for consideration in the development of 

the SER as appropriate. The SER for STP license renewal is available on the web for public 

inspection: 

http://www.nrc.gov/reactors/operating/licensing/renewal/applications/south-texas-project.html

Fukushima lessons learned. On March 11, 2011, a massive earthquake off the east coast of 

Honshu, Japan, produced a devastating tsunami that struck Fukushima. The six-unit 

Fukushima Dai-ichi nuclear power plant was directly impacted by these events. The resulting 

damage caused the failure of several of the units’ safety systems needed to maintain cooling 

water flow to the reactors. As a result of the loss of cooling, the fuel overheated, and there was 

a partial meltdown of the fuel contained in several of the reactors. Damage to the systems and 

structures containing reactor fuel resulted in the release of radioactive material to the 

surrounding environment.

In 2011, the Commission directed the staff to convene an agency task force of senior leaders 

and experts to conduct a methodical and systematic review of the relevant NRC regulatory 

requirements, programs, and processes, including their implementation, and to recommend 

whether the agency should make near-term improvements to its regulatory system. As part of 

the short-term review, the task force concluded that, while improvements are expected to be 

made as a result of the lessons learned from the Fukushima events, the continued operation of 

nuclear power plants and licensing activities for new plants do not pose an imminent risk to 

public health and safety (NRC 2011). 

The NRC will continue to evaluate the need to make improvement to existing regulatory 

requirements based on NRC assessments of the Fukushima events as more information is 

learned. To the extent that any revisions are made to NRC regulatory requirements, they would 

be made applicable to STP regardless of whether or not STP has renewed licenses. The 

information available about the event, NRC assessment of the event, NRC actions in response 

to the event, and other information on the ongoing lessons learned are available for public 

inspection at the NRC web site: 

http://www.nrc.gov/reactors/operating/ops-experience/japan-info.html

A.2.14 Text Clarification

The original sources for the comments in this category (clarification) can be found at the end of 

this Section A.2 and are labeled with the following identifiers: 12-1, 14-2, and 14-6. These 

comments are extracted from the original sources.

Comment 12-1: On Page 2-1, lines 25 and 26, revise the sentence to state “The Units 1 and 2 

steam generators were replaced in 2000 and 2002, respectively, with new Westinghouse steam 

generators.”

On Page 2-27, Figure 2-2, revise the “STAR” legend to read “STP, Units 1 and 2.”

Comment 14-2: The dates listed for the Texas Pollution Discharge Elimination System 

(TPDES) in this section and Table C-1 contradict each other. Section 2.2.4.2 states the TPDES 

permit was administratively continued by the Texas Commission on Environmental Quality 
Appendix A

A-46

(TCEQ) on July 13, 2009, but Table C-1 states a new TPDES permit was approved 

April 5, 2012.

• Clarify the correct date of issuance for the TPDES permit issued to the STP.

Comment 14-6: This section [4.11.3.1] lists many water projects and the respective water use 

totals for each project. As presented, it is difficult to determine the cumulative effects to surface 

water.

• In order to provide a more effective understanding of the cumulative impacts 

to surface water, include a tabular summary of project water use totals in the 

final [S]EIS.

Response: 

These comments are editorial or text clarification in nature. The comments are incorporated 

into the SEIS, as appropriate. The SEIS sections being revised are listed as follow:

Comment SEIS Section Summary

Comment 12-1 2.1.1, 2.2.6.1 Staff updated Section 2.1.1 to correct the dates as specified in the comment. 

There is no change to Figure 2-2 of Section 2.2.6.1 (this Figure 2-2 was extracted 

from the NRC EIS for the proposed STP, Units 3 and 4)

Comment 14-2 2.2.4.2 Staff updated Section 2.2.4.2 relative to the issuance of a revised TPDES permit 

to STPNOC in April 2012 and for consistency with Table C-1 in this SEIS.

Comment 14-6 4.11.3.1 Consistent with the review criteria in the NRC standard review plan for analysis of 

cumulative impacts, the staff takes into account compliance with environmental 

quality standards and requirements that have been imposed by other Federal, 

State, regional, local, and affected Native American tribal agencies. The staff also 

incorporates, by reference, any information contained in final environmental 

documents previously prepared by the NRC staff that relates to the same facility. 

Consequently, as part of the staff’s independent evaluation of the potential 

cumulative impacts on surface water resources presented in Section 4.12.3.1, the 

staff used, and incorporated by reference, the analyses of the major regional 

projects previously considered and presented in two primary sources. These 

reference sources are (1) NRC’s environmental impact statement for combined 

licenses (COLs) for South Texas Project Electric Generating Station, Units 3 and 4 

(cited as NRC 2011b) and (2) the Lower Colorado River Water Planning Group, 

2011 Region K Water Plan (cited as LCRWPG 2010). The staff notes that the 

data presented in these references cannot simply be taken additively for 

comparison purpose to some threshold that correlates to the staff conclusion of 

impact significance (such as in construction of a tabular summary of project water 

use totals).

The staff has revised Sections 4.12.3 and 4.12.3.1 (formerly 4.11.3 and 4.11.3.1) 

to further clarify the references cited and data used, as appropriate, to improve 

clarity with respect to the conclusions drawn for cumulative impacts to surface 

water resources.
Appendix A

A-47

A.3 Public Meeting Transcript Excerpts and Comment Letters

Public Meeting Transcript January 15, 2013, afternoon session

Comment 1-1 
Appendix A

A-48

Comment 1-2 

Comment 2-1 
Appendix A

A-49

Comment 3-1 
Appendix A

A-50
Appendix A

A-51

Comment 4-1 
Appendix A

A-52

Comment 4-2 
Appendix A

A-53

Comment 4-3

Comment 4-4 

Comment 4-5 
Appendix A

A-54

Comment 4-6 

Comment 4-7 

Comment 4-8 
Appendix A

A-55

Comment 4-9 
Appendix A

A-56

Comment 4-10

Comment 4-11
Appendix A

A-57

Comment 4-12
Appendix A

A-58

Comment 4-13

Comment 4-14

Comment 4-15
Appendix A

A-59
Appendix A

A-60

Public Meeting Transcript January 15, 2013, evening session

Comment 5-1 
Appendix A

A-61
Appendix A

A-62

Comment 5-2 
Appendix A

A-63

Comment 5-3 

Comment 5-4 
Appendix A

A-64

Comment 6-1 
Appendix A

A-65

Comment 6-2 

Comment 6-3 

Comment 6-4 
Appendix A

A-66

Comment 6-5 

Comment 4-16
Appendix A

A-67

Comment 4-16 (cont’)

Comment 4-17

Comment 4-18
Appendix A

A-68

Comment 7-1 
Appendix A

A-69

Comment 8-1 
Appendix A

A-70

Comment 9-1 
Appendix A

A-71

Comment 10-1 

Comment 10-2 

Comment 10-3 

Comment 10-4 
Appendix A

A-72

Comment 11-1 

Comment 11-2 
Appendix A

A-73

Comment 12-1 
Appendix A

A-74

Comment 13-1 
Appendix A

A-75

Comment 14-1 

Comment 14-2 

Environmental Protection Agency Comments
Appendix A

A-76

Comment 14-3 

Comment 14-4 

Comment 14-5 
Appendix A

A-77

Comment 14-6 

Comment 14-7 

Comment 14-8 
Appendix A

A-78

Comment 14-9 
Appendix A

A-79

Comment 15-1 
Appendix A

A-80
Appendix A

A-81
Appendix A

A-82
APPENDIX B 

NATIONAL ENVIRONMENTAL POLICY ACT ISSUES FOR LICENSE 

RENEWAL OF NUCLEAR POWER PLANTS

B-1 

B NATIONAL ENVIRONMENTAL POLICY ACT ISSUES FOR LICENSE 

RENEWAL OF NUCLEAR POWER PLANTS

The table in this appendix summarizes the National Environmental Policy Act (NEPA) issues for 

license renewal of nuclear power plants identified in Table B–1 in Appendix B, Subpart A, to 

Title 10 Part 51 of the Code of Federal Regulations (10 CFR Part 51). Data supporting this 

table are contained in NUREG-1437, Generic Environmental Impact Statement for License 

Renewal of Nuclear Plants. Throughout this supplemental environmental impact statement 

(SEIS), “generic” issues are also referred to as Category 1 issues, and “site-specific” issues are 

also referred to as Category 2 issues. In addition, as described in Section 1.4, the U.S. Nuclear 

Regulatory Commission (NRC) has approved a revision to its environmental protection 

regulation, 10 CFR Part 51. The revised rule consolidates similar Category 1 and 2 issues, 

changes some Category 2 issues into Category 1 issues, and consolidates some of those 

issues with existing Category 1 issues. These issues are discussed in Section 4.11.

Table B–1. Summary of Issues and Findings

Issue Type of Issue Finding

Surface Water Quality, Hydrology, and Use 

Impacts of 

refurbishment on 

surface water 

quality

Generic SMALL. Impacts are expected to be negligible during refurbishment 

because best management practices are expected to be employed to 

control soil erosion and spills.

Impacts of 

refurbishment on 

surface water use

Generic SMALL. Water use during refurbishment will not increase appreciably 

or will be reduced during plant outage.

Altered current 

patterns at intake 

and discharge 

structures

Generic SMALL. Altered current patterns have not been found to be a problem 

at operating nuclear power plants and are not expected to be a 

problem during the license renewal term.

Altered salinity 

gradients

Generic SMALL. Salinity gradients have not been found to be a problem at 

operating nuclear power plants and are not expected to be a problem 

during the license renewal term.

Altered thermal 

stratification of 

lakes

Generic SMALL. Generally, lake stratification has not been found to be a 

problem at operating nuclear power plants and is not expected to be a 

problem during the license renewal term.

Temperature 

effects on sediment 

transport capacity

Generic SMALL. These effects have not been found to be a problem at 

operating nuclear power plants and are not expected to be a problem 

during the license renewal term.

Scouring caused 

by discharged 

cooling water

Generic SMALL. Scouring has not been found to be a problem at most 

operating nuclear power plants and has caused only localized effects 

at a few plants. It is not expected to be a problem during the license 

renewal term.

Eutrophication Generic SMALL. Eutrophication has not been found to be a problem at 

operating nuclear power plants and is not expected to be a problem 

during the license renewal term.

Discharge of 

chlorine or other 

Generic SMALL. Effects are not a concern among regulatory and resource 

agencies, and are not expected to be a problem during the license 
Appendix B

B-2 

Issue Type of Issue Finding

biocides renewal term.

Discharge of 

sanitary wastes 

and minor chemical 

spills

Generic SMALL. Effects are readily controlled through National Pollutant 

Discharge Elimination System (NPDES) permit and periodic 

modifications, if needed, and are not expected to be a problem during 

the license renewal term.

Discharge of other 

metals in 

wastewater

Generic SMALL. These discharges have not been found to be a problem at 

operating nuclear power plants with cooling-tower-based heatdissipation systems and have been satisfactorily mitigated at other 

plants. They are not expected to be a problem during the license 

renewal term.

Water use conflicts 

(plants with 

once-through 

cooling systems)

Generic SMALL. These conflicts have not been found to be a problem at 

operating nuclear power plants with once-through heat-dissipation 

systems.

Water use conflicts 

(plants with cooling 

ponds or cooling 

towers using 

makeup water from 

a small river with 

low flow)

Site-specific SMALL OR MODERATE. The issue has been a concern at nuclear 

power plants with cooling ponds and at plants with cooling towers. 

Impacts on instream and riparian communities near these plants could 

be of moderate significance in some situations. 

See §51.53(c)(3)(ii)(A).

Aquatic Ecology 

Refurbishment Generic SMALL. During plant shutdown and refurbishment, there will be 

negligible effects on aquatic biota because of a reduction of 

entrainment and impingement of organisms or a reduced release of 

chemicals.

Accumulation of 

contaminants in 

sediments or biota

Generic SMALL. Accumulation of contaminants has been a concern at a few 

nuclear power plants but has been satisfactorily mitigated by replacing 

copper alloy condenser tubes with those of another metal. It is not 

expected to be a problem during the license renewal term.

Entrainment of 

phytoplankton and 

zooplankton

Generic SMALL. Entrainment of phytoplankton and zooplankton has not been 

found to be a problem at operating nuclear power plants and is not 

expected to be a problem during the license renewal term.

Cold shock Generic SMALL. Cold shock has been satisfactorily mitigated at operating 

nuclear plants with once-through cooling systems, has not 

endangered fish populations, or been found to be a problem at 

operating nuclear power plants with cooling towers or cooling ponds, 

and is not expected to be a problem during the license renewal term.

Thermal plume 

barrier to migrating 

fish

Generic SMALL. Thermal plumes have not been found to be a problem at 

operating nuclear power plants and are not expected to be a problem 

during the license renewal term.

Distribution of 

aquatic organisms

Generic SMALL. Thermal discharge may have localized effects but is not 

expected to affect the larger geographical distribution of aquatic 

organisms.

Premature 

emergence of 

Generic SMALL. Premature emergence has been found to be a localized 

effect at some operating nuclear power plants but has not been a 
Appendix B

B-3 

Issue Type of Issue Finding

aquatic insects problem and is not expected to be a problem during the license 

renewal term.

Gas 

supersaturation

(gas bubble 

disease)

Generic SMALL. Gas supersaturation was a concern at a small number of 

operating nuclear power plants with once-through cooling systems but 

has been satisfactorily mitigated. It has not been found to be a 

problem at operating nuclear power plants with cooling towers or 

cooling ponds and is not expected to be a problem during the license 

renewal term.

Low dissolved 

oxygen in the 

discharge

Generic SMALL. Low dissolved oxygen has been a concern at one nuclear 

power plant with a once-through cooling system but has been 

effectively mitigated. It has not been found to be a problem at 

operating nuclear power plants with cooling towers or cooling ponds 

and is not expected to be a problem during the license renewal term.

Losses from 

predation, 

parasitism, and 

disease among 

organisms exposed 

to sublethal 

stresses

Generic SMALL. These types of losses have not been found to be a problem 

at operating nuclear power plants and are not expected to be a 

problem during the license renewal term.

Stimulation of 

nuisance 

organisms 

(e.g.,shipworms)

Generic SMALL. Stimulation of nuisance organisms has been satisfactorily 

mitigated at the single nuclear power plant with a once-through 

cooling system where previously it was a problem. It has not been 

found to be a problem at operating nuclear power plants with cooling 

towers or cooling ponds and is not expected to be a problem during 

the license renewal term.

Aquatic Ecology (for Plants with Once-Through and Cooling-Pond Heat-Dissipation Systems)

Entrainment of fish 

and shellfish in 

early life stages

Site-specific SMALL, MODERATE, OR LARGE. The impacts of entrainment are 

small at many plants but may be moderate or even large at a few 

plants with once-through and cooling-pond cooling systems. Further, 

ongoing efforts in the vicinity of these plants to restore fish populations 

may increase the numbers of fish susceptible to intake effects during 

the license renewal period, such that entrainment studies conducted in 

support of the original license may no longer be valid. 

See §51.53(c)(3)(ii)(B).

Impingement of 

fish and shellfish

Site-specific SMALL, MODERATE, OR LARGE. The impacts of impingement are 

small at many plants but may be moderate or even large at a few 

plants with once-through and cooling-pond cooling systems. 

See §51.53(c)(3)(ii)(B).

Heat shock Site-specific SMALL, MODERATE, OR LARGE. Because of continuing concerns 

about heat shock and the possible need to modify thermal discharges 

in response to changing environmental conditions, the impacts may be 

of moderate or large significance at some plants. 

See §51.53(c)(3)(ii)(B).

Aquatic Ecology (for Plants with Cooling-Tower-Based Heat-Dissipation Systems)

Entrainment of fish 

and shellfish in 

early life stages

Generic SMALL. Entrainment of fish has not been found to be a problem at 

operating nuclear power plants with this type of cooling system and is 

not expected to be a problem during the license renewal term.
Appendix B

B-4 

Issue Type of Issue Finding

Impingement of 

fish and shellfish

Generic SMALL. The impingement has not been found to be a problem at 

operating nuclear power plants with this type of cooling system and is 

not expected to be a problem during the license renewal term.

Heat shock Generic SMALL. Heat shock has not been found to be a problem at operating 

nuclear power plants with this type of cooling system and is not 

expected to be a problem during the license renewal term.

Groundwater Use and Quality

Impacts of 

refurbishment on 

groundwater use 

and quality

Generic SMALL. Extensive dewatering during the original construction on 

some sites will not be repeated during refurbishment on any sites. 

Any plant wastes produced during refurbishment will be handled in the 

same manner as in current operating practices and are not expected 

to be a problem during the license renewal term.

Groundwater use 

conflicts (potable 

and service water; 

plants that use 

<100 gallons per 

minute (gpm)

Generic SMALL. Plants using less than 100 gpm are not expected to cause 

any groundwater use conflicts.

Groundwater use 

conflicts (potable 

and service water, 

and dewatering 

plants that use 

>100 gpm

Site-specific SMALL, MODERATE, OR LARGE. Plants that use more than 

100 gpm may cause groundwater use conflicts with nearby 

groundwater users. See §51.53(c)(3)(ii)(C).

Groundwater use 

conflicts (plants 

using cooling 

towers withdrawing 

makeup water from 

a small river)

Site-specific SMALL, MODERATE, OR LARGE. Water use conflicts may result 

from surface water withdrawals from small water bodies during low 

flow conditions which may affect aquifer recharge, especially if other 

groundwater or upstream surface water users come online before the 

time of license renewal. See §51.53(c)(3)(ii)(A).

Groundwater use 

conflicts (Ranney 

wells)

Site-specific SMALL, MODERATE, OR LARGE. Ranney wells can result in 

potential groundwater depression beyond the site boundary. Impacts 

of large groundwater withdrawal for cooling tower makeup at nuclear 

power plants using Ranney wells must be evaluated at the time of 

application for license renewal. See §51.53(c)(3)(ii)(C).

Groundwater 

quality degradation 

(Ranney wells)

Generic SMALL. Groundwater quality at river sites may be degraded by 

induced infiltration of poor-quality river water into an aquifer that 

supplies large quantities of reactor cooling water. However, the lower 

quality infiltrating water would not preclude the current uses of 

groundwater and is not expected to be a problem during the license 

renewal term.

Groundwater 

quality degradation 

(saltwater 

intrusion) 

Generic SMALL. Nuclear power plants do not contribute significantly to 

saltwater intrusion.

Groundwater 

quality degradation 

(cooling ponds in 

Generic SMALL. Sites with closed-cycle cooling ponds may degrade 

groundwater quality. Because water in salt marshes is brackish, this 

is not a concern for plants located in salt marshes.
Appendix B

B-5 

Issue Type of Issue Finding

salt marshes)

Groundwater 

quality degradation 

(cooling ponds at 

inland sites)

Site-specific SMALL, MODERATE, OR LARGE. Sites with closed-cycle cooling 

ponds may degrade groundwater quality. For plants located inland, 

the quality of the groundwater in the vicinity of the ponds must be 

shown to be adequate to allow continuation of current uses. 

See §51.53(c)(3)(ii)(D).

Terrestrial Ecology 

Refurbishment 

impacts

Site-specific SMALL, MODERATE, OR LARGE. Refurbishment impacts are 

insignificant if no loss of important plant and animal habitat occurs. 

However, it cannot be known whether important plant and animal 

communities may be affected until the specific proposal is presented 

with the license renewal application. See §51.53(c)(3)(ii)(E).

Cooling tower 

impacts on crops 

and ornamental 

vegetation

Generic SMALL. Impacts from salt drift, icing, fogging, or increased humidity 

associated with cooling tower operation have not been found to be a 

problem at operating nuclear power plants and are not expected to be 

a problem during the license renewal term.

Cooling tower 

impacts on native 

plants

Generic SMALL. Impacts from salt drift, icing, fogging, or increased humidity 

associated with cooling tower operation have not been found to be a 

problem at operating nuclear power plants and are not expected to be 

a problem during the license renewal term.

Bird collisions with 

cooling towers

Generic SMALL. These collisions have not been found to be a problem at 

operating nuclear power plants and are not expected to be a problem 

during the license renewal term.

Cooling pond 

impacts on 

terrestrial 

resources

Generic SMALL. Impacts of cooling ponds on terrestrial ecological resources 

are considered to be of small significance at all sites.

Powerline right-ofway (ROW) 

management 

(cutting and 

herbicide 

application)

Generic SMALL. The impacts of ROW maintenance on wildlife are expected 

to be of small significance at all sites.

Bird collisions with 

powerlines

Generic SMALL. Impacts are expected to be of small significance at all sites.

Impacts of 

electromagnetic 

fields on flora and 

fauna

Generic SMALL. No significant impacts of electromagnetic fields on terrestrial 

flora and fauna have been identified. Such effects are not expected to 

be a problem during the license renewal term.

Floodplains and 

wetland on 

powerline ROW

Generic SMALL. Periodic vegetation control is necessary in forested wetlands 

underneath powerlines and can be achieved with minimal damage to 

the wetland. No significant impact is expected at any nuclear power 

plant during the license renewal term.

Threatened and Endangered Species

Threatened or 

endangered 

Site-specific SMALL, MODERATE, OR LARGE. Generally, plant refurbishment 

and continued operation are not expected to adversely affect 
Appendix B

B-6 

Issue Type of Issue Finding

species threatened or endangered species. However, consultation with 

appropriate agencies would be needed at the time of license renewal 

to determine whether or not threatened or endangered species are 

present and whether or not they would be adversely affected. 

See §51.53(c)(3)(ii)(E).

Air quality

Air quality during 

refurbishment 

(non-attainment 

and maintenance 

areas)

Site-specific SMALL, MODERATE, OR LARGE. Air quality impacts from plant 

refurbishment associated with license renewal are expected to be 

small. However, vehicle exhaust emissions could be cause for 

concern at locations in or near non-attainment or maintenance areas. 

The significance of the potential impact cannot be determined without 

considering the compliance status of each site and the number of 

workers expected to be employed during the outage. 

See §51.53(c)(3)(ii)(F).

Air quality effects 

of transmission 

lines

Generic SMALL. Production of ozone and oxides of nitrogen is insignificant 

and does not contribute measurably to ambient levels of these gases.

Land Use

Onsite land use Generic SMALL. Projected onsite land use changes required during 

refurbishment and the renewal period would be a small fraction of any 

nuclear power plant site and would involve land that is controlled by 

the applicant.

Powerline ROW Generic SMALL. Ongoing use of powerline ROWs would continue with no 

change in restrictions. The effects of these restrictions are of small 

significance.

Human Health

Radiation 

exposures to the 

public during 

refurbishment

Generic SMALL. During refurbishment, the gaseous effluents would result in 

doses that are similar to those from current operation. Applicable 

regulatory dose limits to the public are not expected to be exceeded.

Occupational 

radiation 

exposures during 

refurbishment

Generic SMALL. Occupational doses from refurbishment are expected to be 

within the range of annual average collective doses experienced for 

pressurized-water reactors and boiling-water reactors. Occupational 

mortality risk from all causes including radiation is in the mid-range for 

industrial settings.

Microbiological 

organisms 

(occupational 

health)

Generic SMALL. Occupational health impacts are expected to be controlled by 

continued application of accepted industrial hygiene practices to 

minimize exposure to workers.

Microbiological 

organisms (public 

health) (plants 

using lakes or 

canals, or cooling 

towers or cooling 

ponds that 

discharge to a 

Site-specific SMALL, MODERATE, OR LARGE. These organisms are not 

expected to be a problem at most operating plants except possibly at 

plants using cooling ponds, lakes, or canals that discharge to small 

rivers. Without site-specific data, it is not possible to predict the 

effects generically. See §51.53(c)(3)(ii)(G).
Appendix B

B-7 

Issue Type of Issue Finding

small river)

Noise Generic SMALL. Noise has not been found to be a problem at operating 

plants and is not expected to be a problem at any plant during the 

license renewal term.

Electromagnetic 

fields—acute 

effects (electric 

shock)

Site-specific SMALL, MODERATE, OR LARGE. Electrical shock resulting from 

direct access to energized conductors or from induced charges in 

metallic structures have not been found to be a problem at most 

operating plants and generally are not expected to be a problem 

during the license renewal term. However, site-specific review is 

required to determine the significance of the electric shock potential at 

the site. See §51.53(c)(3)(ii)(H).

Electromagnetic 

fields—chronic 

effects 

Uncategorized UNCERTAIN. Biological and physical studies of 60-hertz 

electromagnetic fields have not found consistent evidence linking 

harmful effects with field exposures. However, research is continuing 

in this area and a consensus scientific view has not been reached.

Radiation 

exposures to public 

(license renewal 

term)

Generic SMALL. Radiation doses to the public will continue at current levels 

associated with normal operations.

Occupational 

radiation 

exposures (license 

renewal term)

Generic SMALL. Projected maximum occupational doses during the license 

renewal term are within the range of doses experienced during normal 

operations and normal maintenance outages, and would be well below 

regulatory limits.

Socioeconomic Impacts

Housing impacts Site-specific SMALL, MODERATE, OR LARGE. Housing impacts are expected to 

be of small significance at plants located in a medium or high 

population area and not in an area where growth control measures 

that limit housing development are in effect. Moderate or large 

housing impacts of the workforce associated with refurbishment may 

be associated with plants located in sparsely populated areas or in 

areas with growth control measures that limit housing development. 

See §51.53(c)(3)(ii)(I).

Public services: 

public safety, social 

services, and 

tourism and 

recreation

Generic SMALL. Impacts to public safety, social services, and tourism and 

recreation are expected to be of small significance at all sites.

Public services: 

public utilities

Site-specific SMALL OR MODERATE. An increased problem with water shortages 

at some sites may lead to impacts of moderate significance on public 

water supply availability. See §51.53(c)(3)(ii)(I).

Public services: 

education 

(refurbishment)

Site-specific SMALL, MODERATE, OR LARGE. Most sites would experience 

impacts of small significance but larger impacts are possible 

depending on site- and project-specific factors. See §51.53(c)(3)(ii)(I).

Public services: 

education (license 

renewal term)

Generic SMALL. Only impacts of small significance are expected.

Offsite land use Site-specific SMALL OR MODERATE. Impacts may be of moderate significance at 
Appendix B

B-8 

Issue Type of Issue Finding

(refurbishment) plants in low population areas. See §51.53(c)(3)(ii)(I).

Offsite land use 

(license renewal 

term)

Site-specific SMALL, MODERATE, OR LARGE. Significant changes in land use 

may be associated with population and tax revenue changes resulting 

from license renewal. See §51.53(c)(3)(ii)(I).

Public services: 

transportation

Site-specific SMALL, MODERATE, OR LARGE. Transportation impacts (level of 

service) of highway traffic generated during plant refurbishment and 

during the term of the renewed license are generally expected to be of 

small significance. However, the increase in traffic associated with the 

additional workers and the local road and traffic control conditions may 

lead to impacts of moderate or large significance at some sites. 

See §51.53(c)(3)(ii)(J).

Historic and 

archaeological 

resources

Site-specific SMALL, MODERATE, OR LARGE. Generally, plant refurbishment 

and continued operation are expected to have no more than small 

adverse impacts on historic and archaeological resources. However, 

the National Historic Preservation Act requires the Federal agency to 

consult with the State Historic Preservation Officer to determine 

whether or not there are properties present that require protection. 

See §51.53(c)(3)(ii)(K).

Aesthetic impacts 

(refurbishment)

Generic SMALL. No significant impacts are expected during refurbishment.

Aesthetic impacts 

(license renewal 

term)

Generic SMALL. No significant impacts are expected during the license 

renewal term.

Aesthetic impacts 

of transmission 

lines (license 

renewal term)

Generic SMALL. No significant impacts are expected during the license 

renewal term.

Postulated Accidents

Design basis 

accidents

Generic SMALL. The NRC staff has concluded that the environmental impacts 

of design-basis accidents are of small significance for all plants.

Severe accidents Site-specific SMALL. The probability weighted consequences of atmospheric 

releases, fallout onto open bodies of water, releases to groundwater, 

and societal and economic impacts from severe accidents are small 

for all plants. However, alternatives to mitigate severe accidents must 

be considered for all plants that have not considered such 

alternatives. See §51.53(c)(3)(ii)(L).

Uranium Fuel Cycle and Waste Management

Offsite radiological 

impacts (individual 

effects from other 

than the disposal of 

spent fuel and 

high-level waste)

Generic SMALL. Offsite impacts of the uranium fuel cycle have been 

considered by the Commission in Table S-3 of this part. Based on 

information in the GEIS, impacts on individuals from radioactive 

gaseous and liquid releases including radon-222 and technetium-99 

are small.

Offsite radiological 

impacts (collective 

effects)

Generic The 100-year environmental dose commitment to the U.S. population 

from the fuel cycle, high-level waste, and spent fuel disposal 

excepted, is calculated to be about 14,800 person rem, or 12 cancer 

fatalities, for each additional 20-year power reactor operating term. 
Appendix B

B-9 

Issue Type of Issue Finding

Much of this, especially the contribution of radon releases from mines 

and tailing piles, consists of tiny doses summed over large 

populations. This same dose calculation can theoretically be 

extended to include many tiny doses over additional thousands of 

years as well as doses outside the United States. The result of such a 

calculation would be thousands of cancer fatalities from the fuel cycle, 

but this result assumes that even tiny doses have some statistical 

adverse health effect which will not ever be mitigated (for example no 

cancer cure in the next thousand years), and that these doses 

projected over thousands of years are meaningful; however, these 

assumptions are questionable. In particular, science cannot rule out 

the possibility that there will be no cancer fatalities from these tiny 

doses. For perspective, the doses are very small fractions of 

regulatory limits, and even smaller fractions of natural background 

exposure to the same populations. 

Nevertheless, despite all the uncertainty, some judgment as to the 

regulatory NEPA implications of these matters should be made and it 

makes no sense to repeat the same judgment in every case. Even 

taking the uncertainties into account, the Commission concludes that 

these impacts are acceptable in that these impacts would not be 

sufficiently large to require the NEPA conclusion, for any plant, that 

the option of extended operation under 10 CFR Part 54 should be 

eliminated. Accordingly, while the Commission has not assigned a 

single level of significance for the collective effects of the fuel cycle, 

this issue is considered Category 1 (Generic).

Offsite radiological 

impacts (spent fuel 

and high-level

waste disposal)

Generic Chapter 6 of this SEIS provides further discussion of these impacts.

Nonradiological 

impacts of the 

uranium fuel cycle

Generic SMALL. The nonradiological impacts of the uranium fuel cycle 

resulting from the renewal of an operating license for any plant are 

found to be small.

Low-level waste 

storage and 

disposal

Generic SMALL. The comprehensive regulatory controls that are in place and 

the low public doses being achieved at reactors ensure that the 

radiological impacts to the environment will remain small during the 

term of a renewed license. The maximum additional onsite land that 

may be required for low-level waste storage during the term of a 

renewed license and associated impacts will be small.

Nonradiological impacts on air and water will be negligible. The 

radiological and nonradiological environmental impacts of long-term 

disposal of low-level waste from any individual plant at licensed sites 

are small. In addition, the Commission concludes that there is 

reasonable assurance that sufficient low-level waste disposal capacity 

will be made available when needed for facilities to be 

decommissioned consistent with NRC decommissioning requirements.

Mixed waste 

storage and 

disposal

Generic SMALL. The comprehensive regulatory controls and the facilities and 

procedures that are in place ensure proper handling and storage, as 

well as negligible doses and exposure to toxic materials for the public 

and the environment at all plants. License renewal will not increase 

the small, continuing risk to human health and the environment posed 

by mixed waste at all plants. The radiological and nonradiological 
Appendix B

B-10

Issue Type of Issue Finding

environmental impacts of long-term disposal of mixed waste from any 

individual plant at licensed sites are small. In addition, the 

Commission concludes that there is reasonable assurance that 

sufficient mixed waste disposal capacity will be made available when 

needed for facilities to be decommissioned consistent with NRC 

decommissioning requirements.

Onsite spent fuel Generic SMALL. The expected increase in the volume of spent fuel from an 

additional 20 years of operation can be safely accommodated on site 

with small environmental effects through dry or pool storage at all 

plants if a permanent repository or monitored retrievable storage is not 

available.

Nonradiological 

waste

Generic SMALL. No changes to generating systems are anticipated for license 

renewal. Facilities and procedures are in place to ensure continued 

proper handling and disposal at all plants.

Transportation Generic SMALL. The impacts of transporting spent fuel enriched up to 

5 percent uranium-235 with average burnup for the peak rod to current 

levels approved by NRC up to 62,000 megawatt days per metric-ton 

uranium and the cumulative impacts of transporting high-level waste 

to a single repository, such as Yucca Mountain, Nevada are found to 

be consistent with the impact values contained in 10 CFR 51.52(c), 

Summary Table S–4, “Environmental Impact of Transportation of Fuel 

and Waste to and from One Light-Water-Cooled Nuclear Power 

Reactor.” If fuel enrichment or burnup conditions are not met, the 

applicant must submit an assessment of the implications for the 

environmental impact values reported in §51.52.

Decommissioning 

Radiation doses Generic SMALL. Doses to the public will be well below applicable regulatory 

standards regardless of which decommissioning method is used. 

Occupational doses would increase no more than 1 man-rem caused 

by buildup of long-lived radionuclides during the license renewal term.

Waste 

management

Generic SMALL. Decommissioning at the end of a 20-year license renewal 

period would generate no more solid wastes than at the end of the 

current license term. No increase in the quantities of Class C or 

greater than Class C wastes would be expected.

Air quality Generic SMALL. Air quality impacts of decommissioning are expected to be 

negligible either at the end of the current operating term or at the end 

of the license renewal term.

Water quality Generic SMALL. The potential for significant water quality impacts from 

erosion or spills is no greater whether decommissioning occurs after a 

20-year license renewal period or after the original 40-year operation 

period, and measures are readily available to avoid such impacts.

Ecological 

resources

Generic SMALL. Decommissioning after either the initial operating period or 

after a 20-year license renewal period is not expected to have any 

direct ecological impacts.

Socioeconomic 

impacts

Generic SMALL. Decommissioning would have some short-term 

socioeconomic impacts. The impacts would not be increased by 

delaying decommissioning until the end of a 20-year relicense period, 

but they might be decreased by population and economic growth.
Appendix B

B-11

Issue Type of Issue Finding

Environmental Justice

Environmental 

justice

Uncategorized NONE. The need for and the content of an analysis of environmental 

justice will be addressed in plant-specific reviews.

Table source: Table B–1 in Appendix B, Subpart A, to 10 CFR Part 51

APPENDIX C 

APPLICABLE REGULATIONS, LAWS, AND AGREEMENTS

C-1 

C APPLICABLE REGULATIONS, LAWS, AND AGREEMENTS

The Atomic Energy Act (AEA) authorizes the U.S. Nuclear Regulatory Commission (NRC) to 

enter into agreement with any state to assume regulatory authority for certain activities. For 

example, in accordance with Section 274 of the AEA, as amended, beginning on March 1, 1963, 

the State of Texas assumed regulatory responsibility over the following nuclear material usages: 

• byproduct materials as defined in Section 11e.(1) of the Act, 

• byproduct materials as defined in Section 11e.(2) of the Act, 

• source materials, and

• special nuclear materials in quantities not sufficient to form a critical mass. 

The Texas Department of State Health Services–Radiation Program administers the Texas 

Agreement State Program. 

In addition to implementing some Federal programs, state legislatures develop state laws, which 

are subject to applicable Federal statutes and regulations. State laws supplement, as well as 

implement, Federal laws for protection of air, water quality, and groundwater. State legislation 

may address solid waste management programs, locally rare or endangered species, and 

historic and cultural resources. 

The Clean Water Act (CWA) allows for primary enforcement and administration through state

agencies, provided the state program is at least as stringent as the Federal program. The state 

program must conform to the CWA and to the delegation of authority for the Federal National 

Pollutant Discharge Elimination System (NPDES) Program from the U.S. Environmental 

Protection Agency (EPA) to the state. In accordance with the CWA, for surface water, the 

primary mechanism to control water pollution is the requirement that directs dischargers 

(e.g., point source dischargers) to obtain an NPDES permit or, in the case of states where the 

authority has been delegated from EPA, a State Pollutant Discharge Elimination System 

(SPDES) permit.

C.1 Federal and State Environmental Requirements

Certain environmental requirements may have been delegated to state authorities for 

implementation, enforcement, or oversight by the applicable Federal agencies in exercising the 

agencies’ regulations. Table C–1 provides a list of STP licenses and permits needed for

compliance with the major requirements of the Texas environmental laws that affect the license 

renewal of South Texas Project (STP). These licenses and permits are addressed in this 

supplemental environmental impact statement (SEIS), pursuant to the NRC ESRP, Section 1.3, 

“Compliance and Consultations,” including applicable tribal consultation.

Table C–1. Licenses and Permits

Permit Number Dates Responsible Agency

License to operate STP, 

Unit 1 NPF-76

Issued: 3/22/1988

Expires: 8/20/2027

NRC

License to operate STP, 

Unit 2 NPF-80

Issued: 12/16/1988

Expires: 12/15/2028

NRC
Appendix C

C-2 

Permit Number Dates Responsible Agency

Hazardous materials 

shipments registration 0622110 550 067S

Issued: 6/29/2011

Expired: 6/30/2012

U.S. Department of 

Transportation

Permits for maintenance,

dredging (barge slip)

10570 Issued: 11/4/2004

Expires: 12/31/2014

U.S. Army Corps of

Engineers (USACE)

Permits for maintenance,

dredging (intake)

SWG-1992-02707

Issued: 7/21/2009

Expires: 12/31/2019

USACE

Texas Pollutant Discharge 

Elimination System Permit WQ0001908000

Issued: 4/5/2012

Expires: 12/1/2014

TCEQ

Air Permit (auxiliary 

boilers) 7410

Issued: 12/23/2004

Expires: 12/23/2014

TCEQ

Air Permit (emission 

sources) 0801

Issued: 1/18/2011

Expires: 1/18/2016

TCEQ

Registration of Industrial 

and Hazardous Waste

30651, EPA ID 

No. TXD020810503

Issued: 8/16/1976

Expires: Not applicable

TCEQ

Potable Water System

Texas Commission on 

Environmental Quality 

(TCEQ) ID 

No. 1610103/1610051

Issued: Not applicable

Expires: Not applicable

TCEQ

Source: STP License Renewal Application (STPNOC 2010).

C.2 References

Several operating permit applications may be prepared and submitted. Regulatory approval or 

permits or both would be received prior to license renewal approval by the NRC. As a 

convenient source of references of environmental requirements, Table C–2 lists representative 

Federal, state, and local approvals by the responsible agencies applicable to license renewal.

Table C–2. Federal, State, and Local Laws and Other Requirements. 

STP is subject to other requirements regarding various aspects of their environmental program. 

Representatives of those requirements are briefly described below.

License, Permit, or Other 

Required Approval (or Submittal)

Responsible 

Agency Authority Relevance

Air Quality Protection

Required for sources that are not 

exempt and are major sources, 

affected sources subject to the Acid 

Rain Program, sources subject to 

new source performance standards, 

or sources subject to National 

Emission Standards for Hazardous 

Air Pollutants

U.S. EPA or 

TCEQ

Texas Air Pollution 

Control 

Regulation—TX 

Administrative 

Code, Title 30

Nuclear Power plants are subject 

to 40 CFR Part 61, Subpart H, 

“National Emissions Standards 

for Emissions of Radionuclides,” 

which is included in the terms and 

conditions of the Title V 

Operating Permit.
Appendix C

C-3 

License, Permit, or Other 

Required Approval (or Submittal)

Responsible 

Agency Authority Relevance

Water Resources Protection

NPDES Permit—Construction Site 

Stormwater—required before 

making point source discharges of 

storm water from a construction 

project that disturbs more than 2 ha

(5 ac) of land

U.S. EPA or 

TCEQ

CWA 

(33 USC 1251 et 

seq.); 

40 CFR Part 122

Any plant refurbishment involving 

construction of more than 2 ha 

(5 ac) of land would require a 

Stormwater Pollution Prevention 

Plan and Construction Site Storm 

Water Discharge Permit. 

NPDES Permit—Industrial Facility 

Stormwater—required before 

making point source discharges of 

storm water from an industrial site

U.S. EPA or 

TCEQ

CWA 

(33 USC 1251 et 

seq.); 

40 CFR Part 122

Stormwater would be discharged 

from the nuclear power plants 

during operations. Stormwater 

would discharge through existing 

outfalls covered by a permit.

NPDES Permit—Process Water 

Discharge—required before making 

point source discharges of industrial 

process wastewater

U.S. EPA or 

TCEQ

CWA 

(33 USC 1251 et 

seq.); 

40 CFR Part 122

Processed industrial wastewater 

would be discharged through 

existing outfalls covered by the 

permit.

Spill Prevention Control and 

Countermeasures Plan—required 

for any facility that could discharge 

diesel fuel in harmful quantities into 

navigable waters or onto adjoining 

shorelines

U.S. EPA or 

TCEQ

CWA 

(33 USC 1251 et 

seq.); 

40 CFR Part 112

A Spill Prevention Control and 

Countermeasures Plan is 

required at nuclear power plants 

storing large volumes of diesel 

fuel or other petroleum products

or both. 

CWA, Section 401, Water Quality 

Certification—required to be 

submitted to the agency 

responsible for issuing any Federal 

license or permit to conduct an 

activity that may result in a 

discharge of pollutants into waters 

of a state

U.S. EPA or 

TCEQ

CWA, Section 401 

(33 USC 1341); 

Certification for operation of a 

nuclear power plant may require 

a Federal license or permit 

(e.g., a CWA, Section 404, Permit

or a CWA, Section 401, Water 

Quality Certification). 

New Underground Storage Tanks 

System Registration—required 

within 30 days of bringing a new 

underground storage tank system 

into service

U.S. EPA or 

TCEQ

Resources 

Conservation and 

Recovery Act 

(RCRA), as 

amended, 

Subtitle I 

(42 USC 

6991a-6991i); 

40 CFR §280.22

This registration is required if new 

underground storage tank 

systems would be installed during 

refurbishment at a nuclear power 

plant.

Above Ground Storage Tank

Permit—required to install, remove, 

repair, or alter any stationary tank 

for the storage of flammable or 

combustible liquids

Applicable 

State Fire 

Marshal

This permit is required if new 

above-ground diesel fuel storage 

tanks would be installed during 

refurbishment at a nuclear power 

plant. In accordance with STP 

ER, there is no refurbishment.

Waste Management & Pollution Prevention

Registration and Hazardous Waste U.S. EPA or RCRA, as Generators of hazardous waste 
Appendix C

C-4 

License, Permit, or Other 

Required Approval (or Submittal)

Responsible 

Agency Authority Relevance

Generator Identification Number—

required before a person who 

generates over 100 kg (220 lb) per 

calendar month of hazardous waste 

ships the hazardous waste off site

TCEQ amended 

(42 USC 6901 et 

seq.), Subtitle C 

must notify EPA that the wastes 

exist and require management in 

compliance with RCRA.

Hazardous Waste Facility Permit—

required if hazardous waste will 

undergo nonexempt treatment by 

the generator; be stored on site for 

longer than 90 days by the 

generator of 1,000 kg (2,205 lb) or 

more of hazardous waste per 

month; be stored on site for longer 

than 180 days by the generator of 

between 100 and 1,000 kg (220 

and 2,205 lb) of hazardous waste 

per month; be disposed of on site; 

or be received from off site for 

treatment or disposal

U.S. EPA or 

TCEQ

RCRA, as 

amended 

(42 USC 6901 et 

seq.), Subtitle C

Hazardous wastes are usually not

disposed of on site at nuclear 

power plants. Hazardous wastes 

generated on site are not 

generally stored for more than 

90 days. However, should a 

nuclear power plant store wastes 

on site for greater than 90 days 

for characterization, profiling, or 

scheduling for treatment or 

disposal, a Hazardous Waste 

Facility Permit would be required.

Emergency Planning & Response

List of Material Safety Data 

Sheets—submission required for 

hazardous chemicals (as defined in 

29 CFR Part 1910) that are stored 

on site in excess of their threshold 

quantities

State and local 

emergency 

planning 

agencies

(State 

Emergency

Response 

Commission or 

SERC) 

Emergency 

Planning and 

Community Rightto-Know Act of 

1986 (EPCRA), 

Section 311 

(42 USC 11021); 

40 CFR §370.20

Nuclear power plant operators 

are required to submit List of 

Material Safety Data Sheets to 

state and local emergency 

planning agencies.

Annual Hazardous Chemical 

Inventory Report—submission 

required when hazardous 

chemicals have been stored at a 

facility during the preceding year in 

amounts that exceed threshold 

quantities

State and local 

emergency 

response 

agencies

(SERC); local 

fire department

EPCRA, 

Section 312 

(42 USC 11022); 

40 CFR §370.25

If hazardous chemicals have 

been stored at a nuclear power 

plant during the preceding year in 

amounts that exceed threshold 

quantities, plant operators would 

be required to submit an Annual 

Hazardous Chemical Inventory 

Report.

Notification of Onsite Storage of an 

Extremely Hazardous Substance—

submission required within 60 days 

after onsite storage begins of an 

extremely hazardous substance in 

a quantity greater than the 

threshold planning quantity

State and local 

emergency 

response 

agencies

(SERC)

EPCRA, 

Section 304 

(42 USC 11004); 

40 CFR §355.30

If an extremely hazardous 

substance stored at a nuclear 

power plant in a quantity greater 

than the threshold planning 

quantity, plant operators would 

prepare and submit the 

Notification of Onsite Storage of 

an Extremely Hazardous 

Substance.

Annual Toxics Release Inventory 

Report—required for facilities that 

have 10 or more full-time 

U.S. EPA or 

TCEQ

EPCRA, 

Section 313 

(42 USC 11023); 

If required, nuclear power plant 

operators would prepare and 

submit a Toxics Release 
Appendix C

C-5 

License, Permit, or Other 

Required Approval (or Submittal)

Responsible 

Agency Authority Relevance

employees and are assigned 

certain standards

40 CFR Part 372 Inventory Report to EPA.

Industrial Classification codes.

Transportation of Radioactive 

Wastes and Conversion Products 

Packaging, Labeling, and Routing 

Requirements for Radioactive 

Materials—required for packages 

containing radioactive materials that 

will be shipped by truck or rail

U.S. 

Department of 

Transportation

Hazardous 

Material 

Transportation Act

(HMTA) 

(49 USC 1501 et 

seq.); AEA, as 

amended (42 USC 

2011 et seq.); 

49 CFR Parts 172, 

173, 174, 177, 

and 397

When shipments of radioactive 

materials are made, nuclear 

power plant operators would 

comply with U.S. Department of 

Transportation packaging, 

labeling, and routing 

requirements.

Biotic Resource Protection

Threatened and Endangered 

Species Consultation—required 

between the responsible Federal 

agencies and affected states to 

ensure that the project is unlikely to

jeopardize the continued existence 

of any species listed at the Federal 

or state level as endangered or 

threatened or result in destruction 

of critical habitat of such species

U.S. Fish and 

Wildlife Service 

(FWS) and 

other 

applicable 

state agencies

(listed in 

Appendix D of 

this SEIS)

Endangered 

Species Act of 

1973, as amended 

(16 USC 1531 et 

seq.)

The NRC would consult with the 

FWS and state agencies 

regarding the impact of license 

renewal on threatened or 

endangered species or their 

critical habitat.

CWA, Section 404, (Dredge and 

Fill) Permit—required to place 

dredged or fill material into waters 

of the U.S., including areas 

designated as wetlands, unless 

such placement is exempt or 

authorized by a Nationwide permit 

or a regional permit (A notice must 

be filed if a Nationwide or regional 

permit applies.)

USACE CWA 

(33 USC 1251 et 

seq.); 

33 CFR Parts 323 

and 330

Any dredging or placement of fill 

material into wetlands within the 

jurisdiction of the USACE at a 

nuclear power plant would require 

a Section 404 permit.

Cultural Resources Protection

Archaeological and Historical 

Resources Consultation—required 

before a Federal agency approves 

a project in an area where 

archaeological or historic resources 

might be located

State Historic 

Preservation 

Officer or 

Tribal Historic 

Preservation 

Officer or both

(listed in 

Appendix D of 

this SEIS)

National Historic 

Preservation Act of 

1966, as amended 

(16 USC 470 et 

seq.); 

Archaeological 

and Historical 

Preservation Act of 

1974 

(16 USC 469-

469c-2); 

Antiquities Act of 

The NRC would consult with the 

State or Tribal Historic 

Preservation Officers or both and 

applicable Indian tribes 

(e.g., tribes that have historical 

ties to the land) regarding the 

impacts of license renewal and 

the results of archaeological and 

architectural surveys of nuclear 

power plant site.
Appendix C

C-6 

License, Permit, or Other 

Required Approval (or Submittal)

Responsible 

Agency Authority Relevance

1906 

(16 USC 431 et 

seq.); 

Archaeological

Resources 

Protection Act of 

1979, as amended 

(16 USC 470aamm)
APPENDIX D 

CONSULTATION CORRESPONDENCE

D-1 

D CONSULTATION CORRESPONDENCE

D.1 Background

The Endangered Species Act of 1973, as amended; the Magnuson–Stevens Fisheries 

Management Act of 1996, as amended; and the National Historic Preservation Act of 1966 

(NHPA) require that Federal agencies consult with applicable state and Federal agencies and 

groups before taking action that may affect threatened or endangered species, essential fish 

habitat, or historic and archaeological resources, respectively. Table D–1 contains a list of 

correspondence between the U.S. Nuclear Regulatory Commission (NRC) and other agencies 

in compliance with these Federal acts. 

Table D–1. Consultation Correspondence

Author Recipient Date of Letter/Email

NRC (B. Pham) Advisory Council on Historic Preservation (D. Klima) January 27, 2011 

(ML110190591)

NRC (B. Pham) Tribal Nation—Ysleta del Sur Pueblo (J. Loera) February 9, 2011 

(ML110190385)

NRC (B. Pham) Tribal Nation—Alabama–Coushatta Tribe (O. Sylestine) February 9, 2011 

(ML110190418)

NRC (B. Pham) Tribal Nation—Kiowa Tribe of Oklahoma (B. Horse) February 9, 2011 

(ML110390244)

NRC (B. Pham) Tribal Nation—Comanche Nation (R. Toahty) February 9, 2011 

(ML110390265)

Tribal Nation—

Tonkawa Tribe of 

Oklahoma (M. Allen)

NRC (Chief, Rules, Announcements, and Directives 

Branch)

February 15, 2011 

(ML110490057)

NRC (B. Pham) U.S. Fish & Wildlife Service (M. Orms) February 16, 2011 

(ML110190429)

NRC (B. Pham) National Marine Fisheries Service (D. Bernhart) February 16, 2011 

(ML110190434)

NRC (B. Pham) Texas Parks & Wildlife Department (K. Boydston) February 16, 2011 

(ML110190571)

NRC (B. Pham) State Historic Preservation Officer (M. Wolfe) February 17, 2011 

(ML110190549)

NRC (B. Pham) Tribal Nation—Tonkawa Tribe of Oklahoma (A. Street) February 17, 2011 

(ML110390321)

NRC (B. Pham) Tribal Nation—Apalachicola Band of Creek Indians 

(M. Blount)

February 17, 2011 

(ML110390321)

NRC (B. Pham) Tribal Nation—Lipan Apache Tribe of Texas 

(B. Barcena Jr.)

February 17, 2011 

(ML110390321)

NRC (B. Pham) Tribal Nation—Lipan Apache Band of Texas 

(D. Romero Jr.)

February 17, 2011 

(ML110390321)
Appendix D

D-2 

Author Recipient Date of Letter/Email

NRC (B. Pham) Tribal Nation—Pamaque Clan of Coahuila Y Tejas 

(J.R. Mendoza)

February 17, 2011 

(ML110390321)

NRC (B. Pham) Tribal Nation—Tap Pilam-Coahuiltecan Nation 

(R. Hernandez)

February 17, 2011 

(ML110390321)

NRC (B. Pham) Tribal Nation—Kickapoo Traditional Council (J. Garza Jr.) February 23, 2011 

(ML110240161)

National Marine 

Fisheries Service 

(T. Mincey)

NRC (T. Tran) March 3, 2011 

(ML110690848)

Tribal Nation—

Apalachicola Band of 

Creek Indians 

(M. Blount)

NRC (Chief, Rules, Announcements, & Directives Branch) March 7, 2011 

(ML110750424)

Tribal Nation—

Kickapoo Traditional 

Council (J. Garza Jr.)

NRC (Chief, Rules, Announcements, & Directives Branch) April 1, 2011 

(ML110980503)

Tribal Nation—Tap 

Pilam–Coahuiltecan 

Nation (R. Hernandez)

NRC (Chief, Rules, Announcements, & Directives Branch) April 1, 2011 

(ML11111A134)

Texas Parks & Wildlife 

Department 

(A. Turner)

NRC (B. Pham) April 20, 2011 

(ML11119A009)

NRC (T. Tran) State Historic Preservation Officer (Bill Martin) April 28, 2011

(ML11259A029)

Pacific Northwest 

National Laboratory 

(T. O'Neil)

State Historic Preservation Officer (Bill Martin) May 2, 2011

(ML11259A029)

U.S. Fish & Wildlife 

Service (M. Orms) NRC (T. Tran) June 2, 2011 (ML11173A235)

NRC (D. Wrona) Tribal Nation—Kickapoo Traditional Council (J. Garza Jr.) November 17, 2011 

(ML11269A011)

NRC (D. Wrona) Tribal Nation—Tonkawa Tribe of Oklahoma (M. Allen) November 17, 2011 

(ML11269A015)

NRC (D. Wrona) Tribal Nation—Tap 

Pilam–Coahuiltecan Nation (R. Hernandez)

November 29, 2011 

(ML11269A112)

NRC (D. Wrona) Tribal Nation—Apalachicola Band of Creek Indians 

(M. Blount)

January 19, 2012 

(ML11269A063)

NRC (M. Wong) U.S. Fish and Wildlife Service (B. Tuggle) December 10, 2012 

(ML12285A415)
Appendix D

D-3 

Author Recipient Date of Letter/Email

NRC (M. Wong) National Marine Fisheries Service (R. Crabtree) December 10, 2012 

(ML12286A010)

NRC (M. Wong) National Marine Fisheries Service (M. Croom) December 11, 2012

(ML12285A197)

NRC (M. Wong) Tribal Nation—Alabama–Coushatta Tribe (O. Sylestine) December 18, 2012 

(ML12321A351)

NRC (M. Wong) Tribal Nation—Kiowa Tribe of Oklahoma (R. Twohatchet) December 18, 2012 

(ML12321A351)

NRC (M.Wong) Tribal Nation—Comanche Nation of Oklahoma 

(W. Coffey)

December 18, 2012 

(ML12321A351)

NRC (M. Wong) Tribal Nation—Tonkawa Tribe of Oklahoma (D. Patterson) December 18, 2012 

(ML12321A351)

NRC (M. Wong) Tribal Nation—Apalachicola Band of Creek Indians 

(M. Sixwoman Blount)

December 18, 2012 

(ML12321A351)

NRC (M. Wong) Tribal Nation—Lipan Apache Tribe of Texas 

(B. Barcena, Jr.) 

December 18, 2012 

(ML12321A351)

NRC (M.Wong) Tribal Nation—Pamaque Clan of Coahuila y Tejas 

(J.R. Mendoza)

December 18, 2012 

(ML12321A351)

NRC (M. Wong) Tribal Nation—Tap-Pilam Coahuiltecan Nation 

(R. Hernandez)

December 18, 2012 

(ML12321A351)

NRC (M. Wong) Tribal Nation—Kickapoo Traditional Council of Texas 

(J. Garza)

December 18, 2012 

(ML12321A351)

NRC (M.Wong) Tribal Nation—Ysleta del Sur Pueblo (F. Paiz) December 18, 2012 

(ML12321A351)

Tribal Nation—Ysleta 

del Sur Pueblo NRC (M. Wong) January 10, 2013 (ML13030A445)

NRC (E. Larson) Tribal Nation—Carrizo/Comecrudo Tribe of Texas 

(J. Mancias)

January 17, 2013 

(ML13029A795)

NRC (E. Larson) Tribal Nation—Atakapa Indians January 17, 2013 

(ML13029A796)

National Marine 

Fisheries Service 

(N. Bailey)

NRC (B. Balsam) January 29, 2013 

(ML13036A306)

NRC (E. Larson) Tribal Nation—Apalachicola Band of Creek Indians 

(M. Blount)

January 29, 2013 

(ML13029A797)

NRC (B. Balsam) U.S. Fish & Wildlife Service (M. Belton) January 31, 2013 

(ML13036A305)

Tribal Nation—

Apalachicola Band of 

Creek Indiands

NRC (M. Wong) February 21, 2013 

(ML13072A072)
Appendix D

D-4 

Author Recipient Date of Letter/Email

National Marine 

Fisheries Service 

(H. Young)

NRC (B. Balsam) March 1, 2013 

(ML13063A071)

U.S. Fish and Wildlife 

Service (M. Belton) NRC (B. Balsam) March 14, 2013 (ML13077A117)

D.2 Consultation Correspondence

The following pages contain copies of the letters listed in Table D–1. 
Appendix D

D-5 
Appendix D

D-6 
Appendix D

D-7 
Appendix D

D-8 
Appendix D

D-9 
Appendix D

D-10
Appendix D

D-11
Appendix D

D-12
Appendix D

D-13
Appendix D

D-14
Appendix D

D-15
Appendix D

D-16
Appendix D

D-17
Appendix D

D-18
Appendix D

D-19
Appendix D

D-20
Appendix D

D-21
Appendix D

D-22
Appendix D

D-23
Appendix D

D-24
Appendix D

D-25
Appendix D

D-26
Appendix D

D-27
Appendix D

D-28
Appendix D

D-29 
Appendix D

D-30
Appendix D

D-31
Appendix D

D-32
Appendix D

D-33
Appendix D

D-34
Appendix D

D-35
Appendix D

D-36
Appendix D

D-37
Appendix D

D-38
Appendix D

D-39
Appendix D

D-40
Appendix D

D-41
Appendix D

D-42
Appendix D

D-43
Appendix D

D-44
Appendix D

D-45
Appendix D

D-46
Appendix D

D-47
Appendix D

D-48
Appendix D

D-49
Appendix D

D-50
Appendix D

D-51
Appendix D

D-52
Appendix D

D-53
Appendix D

D-54
Appendix D

D-55
Appendix D

D-56
Appendix D

D-57
Appendix D

D-58
Appendix D

D-59
Appendix D

D-60
Appendix D

D-61
Appendix D

D-62
Appendix D

D-63
Appendix D

D-64
Appendix D

D-65
Appendix D

D-66
Appendix D

D-67
Appendix D

D-68
Appendix D

D-69
Appendix D

D-70
Appendix D

D-71
Appendix D

D-72
Appendix D

D-73
Appendix D

D-74
Appendix D

D-75
Appendix D

D-76
Appendix D

D-77
Appendix D

D-78
Appendix D

D-79
Appendix D

D-80
Appendix D

D-81
Appendix D

D-82
Appendix D

D-83
Appendix D

D-84
Appendix D

D-85
Appendix D

D-86
Appendix D

D-87
Appendix D

D-88
Appendix D

D-89
Appendix D

D-90
Appendix D

D-91
Appendix D

D-92
Appendix D

D-93
Appendix D

D-94
Appendix D

D-95
Appendix D

D-96
Appendix D

D-97
Appendix D

D-98
Appendix D

D-99
Appendix D

D-100
Appendix D

D-101
Appendix D

D-102
Appendix D

D-103
Appendix D

D-104
Appendix D

D-105
Appendix D

D-106
Appendix D

D-107
Appendix D

D-108
Appendix D

D-109
Appendix D

D-110
Appendix D

D-111
Appendix D

D-112
Appendix D

D-113
Appendix D

D-114

 
Appendix D

D-115
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D-116
Appendix D

D-117
Appendix D

D-118
Appendix D

D-119
Appendix D

D-120
Appendix D

D-121
Appendix D

D-122
Appendix D

D-123
Appendix D

D-124
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D-125
Appendix D

D-126
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D-127
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D-128
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D-129
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D-130
Appendix D

D-131
Appendix D

D-132
Appendix D

D-133
Appendix D

D-134
APPENDIX E 

CHRONOLOGY OF ENVIRONMENTAL REVIEW CORRESPONDENCE

E-1 

E CHRONOLOGY OF ENVIRONMENTAL REVIEW CORRESPONDENCE

This appendix contains a chronological listing of correspondence between the U.S. Nuclear 

Regulatory Commission (NRC) and external parties as part of its environmental review for the 

South Texas Project (STP). All documents, with the exception of those containing proprietary 

information, are available electronically from the NRC’s Public Electronic Reading Room, which 

is found on the Internet at the following web address: http://www.nrc.gov/reading-rm.html. 

From this site, the public can gain access to the NRC’s Agencywide Documents Access and 

Management System (ADAMS), which provides text and image files of NRC’s public 

documents. The ADAMS accession number for each document is included below.

E.1 Environmental Review Correspondence

Table E–1 lists the environmental review correspondence in date order beginning with the 

request by South Texas Project Nuclear Operating Company (STPNOC) to renew the operating 

licenses for STP.

Table E–1. Environmental Review Correspondence

Date Correspondence Description ADAMS No.

10/25/10 STP, Units 1 and 2, Transmittal of LRA ML103010257

11/4/10 Press Release-10-202, “NRC Announces Availability of License Renewal 

Application for South Texas Project Nuclear Power Plant” 

ML103081029

11/23/10 Maintenance of Reference Materials at the Bay City Public Library for the 

Review of STP License Renewal Application

ML103090389

11/23/10 Receipt and availability of the LRA For STP, Units 1 and 2 (LTR) ML103020399

12/9/10 Project Manager Change for the License Renewal of STP, Units 1 and 2 (TAC 

No. ME4936)

ML103410524

1/6/11 Acceptance of LRA for STP, Units 1 and 2 ML103440610

1/7/11 Determination of acceptability and sufficiency for docketing, proposed review 

schedule, and opportunity for a hearing regarding the application from STPNOC

for renewal of the operating licenses for STP electric gene

ML103420531

1/7/11 Notice of acceptance for docketing of the application and notice of opportunity for 

hearing regarding renewal of facility operating license numbers NPF-76 and 

NPF-80 for an additional 20-year period STPNOC, STP

ML103420650

1/13/11 Press Release-11-009: “NRC Announces Opportunity for Hearing on Application 

to Renew Operating Licenses for South Texas Project Nuclear Power Plant” 

ML110130500

1/21/11 Notice of intent to prepare an environmental impact statement (EIS) and conduct 

scoping process for license renewal for STP, Units 1 and 2 

ML103490511

1/25/11 3/2/11—forthcoming meeting to discuss the license renewal process and 

environmental scoping for STP, Units 1 and 2, LRA review 

ML103510697

1/27/11 STP, Units 1 and 2, LRA review (ACHP) ML110190591

1/31/11 Comment (44) of Edmund E. Kelley, opposing STP, Units 1 and 2, LRA review ML11105A023

1/31/11 Comment (51) of Juan Aguilar, on behalf of self, opposed to relicensing of STP, 

Units 1 and 2 

ML11119A011
Appendix E

E-2 

Date Correspondence Description ADAMS No.

1/31/11 Comment (52) of Juan Aguilar, on behalf of self, opposing STP, Units 1 and 2, 

relicensing application

ML11119A012

1/31/11 Comment (54) of Shawn Tracy, on behalf of self, opposing STP, Units 1 and 2, 

relicensing application

ML11119A014

2/7/11 Press Release-11-017: “NRC to Meet with Public March 2 for Input on South 

Texas Project Nuclear Plant Environmental Review for License Renewal” 

ML110380405

2/9/11 Comanche Nation—request for comments concerning the STP, Units 1 and 2, 

LRA review 

ML110390265

2/9/11 Kiowa Tribe of Oklahoma—Request for comments concerning the STP, Units 1 

and 2, LRA review

ML110390244

2/9/11 Ysleta del Sur Pueblo—Request for comments concerning the STP, Units 1 

and 2, LRA review

ML110190385

2/9/11 Alabama-Coushatta Tribe—Request for comments concerning the STP, Units 1 

and 2, LRA review

ML110190418

2/15/11 Comment (1) of Miranda Allen, on behalf of the Tonkawa Tribe of Oklahoma on 

request for comments concerning the STP, Units 1 and 2, LRA review 

ML110490057

2/16/11 Request for list of Federally protected species and important habitats within the 

area under evaluation for the STP, Units 1 and 2, license renewal (FWS)

ML110190429

2/16/11 Request for list of Federally protected species and important habitats within the 

area under evaluation for the STP, Units 1 and 2, LRA review (NMFS) 

ML110190434

2/16/11 Request for list of state-protected species and important habitats within the area 

under evaluation for the STP, Units 1 and 2, LRA review (Texas Parks and 

Wildlife Department) 

ML110190571

2/17/11 Request for comments concerning the STP, Units 1 and 2, LRA review (Tribes) ML110390321

2/17/11 STP, Units 1 and 2, LRA online reference portal ML110610201

2/17/11 STP, Units 1 and 2, LRA review (SHPO) ML110190549

2/23/11 Kickapoo Traditional Council—Request for comments concerning the STP, 

Units 1 and 2, LRA review

ML110240161

2/28/11 Comment (46) of Randy K. Weber, on behalf of Texas House of 

Representatives, supporting license renewal for STP, Units 1 and 2 

ML11108A059

2/28/11 Schedule for the conduct of review of the STP, Units 1 and 2, LRA ML110340478

3/3/11 3/3/11—NRR e-mail capture—STP (NMFS) ML110690848

3/7/11 Comment (3) of Mary Sixwomen Blount, on behalf of Apalachicola Creek Indians, 

on STP, Units 1 and 2, LRA

ML110750424

3/11/11 Comment (2) of Vicki Adams, approving notice of intent to prepare an EIS and 

conduct the scoping process for STP, Units 1 and 2

ML110730188

3/14/11 Declaration of Karen Hadden on behalf of SEED Coalition ML110740852

3/14/11 Declaration of Susan Dancer on behalf of SEED Coalition ML110740850

3/14/11 Notice of appearance of Susan Dancer on behalf of SEED Coalition ML110740851

3/14/11 Petition for leave to intervene and request for hearing of SEED Coalition and 

Susan Dancer

ML110740848

3/16/11 Referral memorandum of the Secretary to the Board regarding license 

application request for STPNOC, STP, Units 1 and 2 

ML110750603
Appendix E

E-3 

Date Correspondence Description ADAMS No.

3/17/11 Referral memorandum of the Secretary to the Board regarding license 

application request for STPNOC, STP, Units 1 and 2 (reissued) 

ML110760289

3/17/11 STP, Units 1 and 2, LRA online reference portal ML110620203

3/23/11 Establishment of Atomic Safety and Licensing Board in the matter of STPNOC, 

STP, Units 1 and 2, license renewal

ML110820735

3/24/11 Comment (31) of Jennifer Meador, opposing relicensing of STP, Units 1 and 2 ML111010604

3/28/11 Comment (34) of unknown individual, supporting nuclear power and relicensing 

of STP, Units 1 and 2 

ML111010507

3/28/11 Comment (37) of Carolyn Campbell, opposing STP, Units 1 and 2, relicensing

(NRC-2010-0375)

ML111010510

3/28/11 Comment (48) of Beth Ann Larsen, on behalf of self, opposing STP, Units 1 

and 2, relicensing application

ML11119A007

3/28/11 Comment (49) of Dzan Nguyen, opposed to relicensing STP, Units 1 and 2 ML11119A008

3/28/11 Comment (55) of Kelly Simon, on behalf of self, opposing relicensing of STP

nuclear reactors

ML11119A015

3/28/11 Comment (58) of Cynthia Gebhardt, on behalf of self, opposing STP, Units 1 

and 2, relicensing application

ML11119A018

3/28/11 Comment (59) of Rory Holcomb, on behalf of self, opposing STP, Units 1 and 2, 

relicensing application

ML11119A019

3/29/11 Comment (4) of Julie Sharp, on behalf of National Park Service, in regards to 

STPNOC STP with determination that no park units will be affected

ML110910179

3/30/11 Comment (32) Of Joy Malacara, opposing relicensing of STP, Units 1 and 2 ML111010479

3/30/11 Comment (33) of Melanie and David Winters, opposing STP, Units 1 and 2,

relicensing

ML111010506

3/30/11 Comment (35) of Christine Fry, opposing STP, Units 1 and 2, relicensing

(NRC-2010-0375) 

ML111010508

3/30/11 Comment (36) of Leona A. Slodge, opposing STP, Units 1 and 2, relicensing ML111010509

3/30/11 Comment (39) of B. Dunlap and T. Rinehart, opposing relicensing of STP, Units 

1 and 2

ML111010517

3/30/11 Comment (40) of Peggy Cravens, opposing the relicensing of STP, Units 1 and 2 ML111010518

3/30/11 Comment (53) of Douglas S. McArthur, opposing relicensing of STP ML11119A013

3/30/11 Comment (6) of Eva Esparza, opposing STPNOC’s notice of intent to prepare an 

EIS and conduct the scoping process for STP, Units 1 and 2

ML110960078

3/30/11 Comment (60) of unknown individual on behalf of self, opposing relicensing of 

STP, Units 1 and 2, for an additional 20 years

ML11119A020

3/30/11 Comment (7) of Darby Riley, regarding notice of intent to prepare an EIS and 

conduct the scoping process for STP, Units 1 and 2 

ML110960079

3/30/11 Comment (38) of Melanie Sallis, opposing the relicensing of STP, Units 1 and 2 ML11273A082

3/31/11 Comment (10) of Karen Seal, opposing the licensing of STP, Units 1 and 2 ML110960082

3/31/11 Comment (5) of Peggy Pryor, opposing STP plants ML110960077

3/31/11 Comment (8) of Kamala Platt, opposing STP relicensing ML110960080
Appendix E

E-4 

Date Correspondence Description ADAMS No.

3/31/11 Comment (9) of Marion Mlotok, opposing the renewal of STP, Units 1 and 2 ML110960081

4/1/11 Comment (11) of Kassandra Levay, opposing STPNOC’s notice of intent to 

prepare an EIS and conduct the scoping process for STP, Units 1 and 2

ML110960083

4/1/11 Comment (12) of unknown individual, regarding notice of intent to prepare an EIS

and conduct the scoping process for STP, Units 1 and 2

ML110960084

4/1/11 Comment (13) of T. Burns, opposing South Texas plants (NRC-2010-0375) ML110960086

4/1/11 Comment (14) of Jolly J. Clark, opposing the relicensing of STP, Units 1 and 2 ML110960087

4/1/11 Comment (15) of Pat Bulla, regarding the decommissioning of STP, Units 1 

and 2, not relicensing it

ML110960088

4/1/11 Comment (16) of William Stout, supporting the decommissioning of STP, Units 1 

and 2, not relicensing it

ML110960089

4/1/11 Comment (19) of Carol Geiger, opposing the renewal of STP, Units 1 and 2,

licensing

ML110960092

4/1/11 Comment (20) of Veryan Thompson, supporting STP, Units 1 and 2,

decommissioning and denying its LRA

ML110960093

4/1/11 Comment (21) of Robert Singleton, opposing license extension for STP, Units 1 

and 2 

ML110960094

4/1/11 Comment (22) of Karen Hadden, on behalf of sustainable energy and economic 

development coalition, opposing relicensing of STP, Units 1 and 2 

ML110960095

4/1/11 Comment (23) of Alan Alan Apurim, opposing relicensing of STP, Units 1 and 2 ML110960096

4/1/11 Comment (24) of Brandi Clark Burton, on behalf of self, opposing STP, Units 1 

and 2, extending its license application renewal for public safety and 

environmental reasons

ML110960097

4/1/11 Comment (25) of Carol Geiger, on behalf of self, opposing STP, Units 1 and 2, 

extending its license application renewal

ML110960098

4/1/11 Comment (27) of Juan Garza, on behalf of Kickapoo Traditional Tribe of Texas, 

on the STP, Units 1 and 2, LRA review 

ML110980503

4/1/11 Comment (45) of Maria Hogan, on safety standards of STP, Units 1 and 2, being

followed

ML11105A020

4/1/11 Comment (47) of Miguel Acosta, on behalf of Raymond Hernandez of Tap Pilam 

Coahuiltecan Nation, opposing the renewal license for STP, Units 1 and 2

ML11111A134

4/4/11 Comment (17) of C.J. Keudell, opposing the relicensing of STP, Units 1 and 2 ML110960090

4/4/11 Comment (18) of Tarek Tonsson, opposing the relicensing of STP, Units 1 and 2 ML110960091

4/4/11 Comment (26) of Eric Lane, on behalf of self, opposing STP, Units 1 and 2, 

extending its license application renewal

ML110960099

4/5/11 Project Manager change for the license renewal of STP, Units 1 and 2 (TAC 

No. ME4938)

ML110872079

4/7/11 4/7/11—Notice of appearance of Steven P. Frantz (STPNOC) ML110970467

4/7/11 4/7/11—The NRC staff’s answer to petition for leave to intervene and request for 

hearing of SEED Coalition and Susan Dancer

ML110970659

4/7/11 STPNOC’s answer opposing request for hearing and petition for leave to 

intervene

ML110970544
Appendix E

E-5 

Date Correspondence Description ADAMS No.

4/8/11 Comment (28) of Jenna Findley, opposing STP, Units 1 and 2, relicensing 

(NRC-2010-0375)

ML111010476

4/8/11 Comment (29) of Margaret Reed, opposing the relicensing of STP, Units 1 and 2 ML111010477

4/8/11 Comment (30) of Scott and Cyndy Reynolds, opposing relicensing of STP 

Nuclear reactors 

ML111010478

4/9/11 Comment (43) of Thomas Nehms, opposing the relicensing of STP, Units 1 

and 2 

ML111010521

4/11/11 Comment (41) of Shannon Jurak, opposing the relicensing of STP, Units 1 and 2 ML111010519

4/11/11 Comment (42) of Thomas Nelms, opposing the relicensing of STP, Units 1 and 2 ML111010520

4/20/11 Comment (61) of Amy Turner, on behalf of Texas Parks and Wildlife, on 

proposed license renewal of STP, Units 1 and 2, Matagorda County, TX

ML11119A009

4/26/11 Comment (50) of John Trimble, opposing relicensing of STP, Units 1 and 2

(NRC-2010-0375) 

ML11119A010

4/26/11 Comment (56) of unknown individual, opposing STP, Units 1 and 2, LRA ML11119A016

4/26/11 Comment (57) of Judy Moore, on behalf of self, opposing relicensing of STP

nuclear reactors

ML11119A017

5/5/11 Notice of withdrawal of Megan Wright in the matter of STP, Units 1 and 2 ML111250147

5/8/11 Interveners request for oral argument on contentions raised on relicensing ML111280003

5/8/11 Petitioners’ proposed amended petition for leave to intervene and request for 

hearing of SEED Coalition and Susan Dancer

ML111280002

5/9/11 Notice of withdrawal of Emily Monteith ML111290341

5/11/11 Certificate of service for amended petition to intervene and request for hearing ML111310798

5/11/11 Certificate of service for request for oral hearing ML111310800

5/19/11 Summary of meeting with stakeholders to discuss issues related to the review of 

the STP, Units 1 and 2, LRA

ML110770661

5/23/11 Memorandum (notice pursuant to 10 CFR §2.309(i)) ML111430828

5/23/11 Order (scheduling oral argument) ML111430799

5/31/11 RAIs for the review of the STP LRA ML11140A015

6/2/11 U.S. Fish and Wildlife Service Consultation #65533—STPNOC ML11173A235

6/2/11 The NRC staff’s answer to proposed amended petition for leave to intervene and 

request for hearing of SEED Coalition and Susan Dancer

ML111530393

6/2/11 STPNOC’s answer opposing amended petition to intervene ML111530425

6/13/11 Press Release-11-103: “Licensing Board to Hold Teleconference Oral Argument 

June 27 on South Texas Project Reactor License Renewal Application” 

ML11166A046

6/17/11 Summary of telephone conference call held on 5/18/11 between the NRC and 

STP, concerning RAI pertaining to the STP LRA—severe accident mitigation 

alternative RAI

ML11143A166

6/17/11 RAI for the review of the STP LRA ML11167A113

6/21/11 Plan for the environmental-related regulatory audit regarding the STP, Units 1 

and 2, LRA Review (TAC Nos. ME4938 and ME4939)

ML11145A064
Appendix E

E-6 

Date Correspondence Description ADAMS No.

6/27/11 Transcript of STPNOC’s oral argument (telephone conference) on 

June 27, 2011, pages 1–22

ML11182B033

7/5/11 STP, Units 1 and 2, response to RAI for the review of the LRA ML11193A074

7/5/11 STP, Units 1 and 2, response to RAI for the STP LRA ML11193A016

7/18/11 Audit report regarding STP LRA—cultural resource ML11173A304

7/27/11 License renewal environmental review for STP, Units 1 and 2 (open 

meeting/records request, CPGCD) 

ML11217A017

7/28/11 Memorandum revised (notice pursuant to 10 CFR §2.309(i)) ML11210B458

8/4/11 RAI for the review of the STP LRA (TAC Nos. ME4938 and ME5122) ML11201A062

8/4/11 Summary of site audit related to the review of the LRA for STP, Units 1 and 2 ML11196A005

8/18/11 RAI for the review of the STP LRA (TAC Nos. ME4938 and ME512) ML11214A207

8/22/11 Comment (63) of Sandra Horris, on behalf of Coastal Plains Groundwater 

Conservation District, on relicensing of STP, Units 1 and 2 (NRC-2010-0375) 

ML11249A042

8/23/11 STP, Units 1 and 2, response to RAI for LRA ML11250A067

8/23/11 Summary of telephone conference call held on July 28, 2011, between the NRC 

and STPNOC, concerning RAI pertaining to the STP LRA

ML11216A263

8/26/11 Memorandum and order (ruling on petition for leave to intervene and request for 

hearing)

ML11238A160

8/31/11 Documents to support review of the STP LRA, list of transmitted documents 

including copy of each document, and enclosure to NOC-AE-11002720

ML11256A057

8/31/11 Documents to support review of the STP LRA, WR–11, “A Summary of Historic 

and Current (past 5 years) Total Dissolved Solids Data for Groundwater 

Produced by STP Production Wells from the Deep Chicot Aquifer”

ML11256A059

8/31/11 Documents to support review of the STP LRA, WR–5, TCEQ ID 

No. 1610103/1610051, “Operation Of Public Potable Water System” 

ML11256A058

8/31/11 STP, Units 1 and 2, transmittal of documents to support review of the STP LRA ML11256A056

9/1/11 RAI for the review of the STP LRA ML112360114

9/6/11 STP, Units 1 and 2, response to RAI for the LRA ML11255A211

9/12/11 STP, Units 1 and 2, response to RAI for the LRA ML11259A014

9/12/11 STP, Units 1 and 2, transmittal of document to support review of the LRA ML11259A031

9/13/11 NRR e-mail capture, STP license renewal, State Historic Preservation Office

meeting

ML11259A029

9/22/11 STP, Units 1 and 2, response to RAIs for LRA (TAC Nos. ME4938 and ME5122) ML11270A060

9/28/11 RAIs for the review of the STP LRA (TAC Nos. ME4938 And ME5122) ML11269A002

10/18/11 STP, Units 1 and 2, response to RAIs for LRA (TAC Nos. ME4938 and ME5122) ML11298A085

10/26/11 STP, Units 1 and 2, contact information change, LRA (TAC Nos. ME4936 

and ME4937)

ML11305A075

10/26/11 STP, Units 1 and 2, correction to NRC distribution list ML11307A371

11/17/11 STP, Units 1 and 2, license renewal environmental review (Kickapoo Traditional 

Council)

ML11269A011
Appendix E

E-7 

Date Correspondence Description ADAMS No.

11/17/11 STP, Units 1 and 2, license renewal environmental review (Tonkawa Tribe of 

Oklahoma)

ML11269A015

11/17/11 STP, Units 1 and 2, clarification to response to RAI for LRA (TAC Nos. ME4938 

and ME5122)

ML11333A094

11/29/11 Summary of telephone conference call held on 11/1/11 between the NRC and 

STPNOC concerning RAIs pertaining to the STP LRA

ML11307A381

11/29/11 STP, Units 1 and 2, license renewal environmental review ( Tap Pilam, 

Coahuiltecan Nation)

ML11269A112

1/4/12 Summary of telephone conference call held on 12/15/11 between NRC and 

STPNOC concerning RAI pertaining to the STP LRA

ML11350A222

1/10/12 STP, Units 1 and 2, clarification of Information in support of the review of the 

LRA

ML12011A188

1/19/12 STP, Units 1 and 2, license renewal environmental review ML11269A063

2/14/12 Summary of telephone conference call held on 1/31/12 between the NRC and 

STPNOC concerning RAIs pertaining to the STP LRA

ML12033A134

2/16/12 STP, Units 1 and 2, clarification to response to RAI for LRA (TAC Nos. ME4938 

and ME5122)

ML12053A259

2/29/12 RAI for the Review of the STP LRA (TAC Nos. ME4938 And ME5122) ML12017A128

2/29/12 Summary of telephone conference call held on 1/7/12 between the NRC and 

STPNOC concerning RAIs pertaining to the STP

ML12047A285

3/12/12 STP, Units 1 and 2, response to RAIs for LRA (TAC Nos. ME4938 and ME5122) ML12079A014

4/17/12 STP, Units 1 and 2, renewal of the Wastewater Discharge Permit ML12114A198

5/8/12 NEPA consultation—Waterborne outbreak ML12128A061

5/18/12 Environmental Permit Updated Status ML12142A002

8/10/12 Revision of schedule for the conduct of environmental review of the STP LRA

(TAC Nos. ME5122, ME5123, ME4938, and ME4939)

ML12171A483

11/14/12 Issuance of environmental scoping summary report associated with the staff’s

review of the application by STPNOC for renewal of the operating license for 

STP, Units 1 and 2 (TAC No. ME4938)

ML11153A082

11/30/12 NUREG-1437, Supplement 48 DFC, Generic Environmental Impact Statement 

for License Renewal of Nuclear Plants: Regarding South Texas Project, Units 1 

and 2 (draft for comment) 

ML12324A049

12/5/12 Notice of availability of the draft plant-specific supplement 48 to the GEIS for 

license renewal of nuclear plants regarding STP, Units 1 and 2 

(TAC Nos. ME5122, ME5123, ME4938, and ME4939).

ML12195A085

12/5/12 Notice of availability of the draft plant-specific supplement 48 to the GEIS for 

license renewal of nuclear plants regarding STP, Units 1 and 2

ML12200A358

12/5/12 Notice of availability of the draft plant-specific supplement 48 to the GEIS for 

license renewal of nuclear plants regarding STP, Units 1 and 2

(TAC Nos. ME5122, ME5123, ME4938, and ME4939)

ML12339A265

12/10/12 Request for concurrence on the effects of the proposed STP license renewal on 

threatened and endangered species

ML12285A415

12/10/12 Request for concurrence on the effects of the proposed STP license renewal on 

threatened and endangered species

ML12286A010
Appendix E

E-8 

Date Correspondence Description ADAMS No.

12/11/12 Request for essential fish habitat consultation for the proposed STP, Units 1 

and 2, license renewal

ML12285A197

12/13/12 STP, Units 1 and 2, LRA review (THC No. 201002271) ML12320A603

12/18/12 STP, Units 1 and 2, LRA review ML12321A311

12/18/12 Notice of availability of the DSEIS for license renewal of STP, Units 1 and 2, for 

public comment

ML12321A351

12/18/12 Press Release-12-128: “NRC Seeks Public Comment on Draft Environmental 

Report for South Texas Project Nuclear Plant License Renewal” 

ML12353A356

12/20/12 Comment (1) of Marvin Lewis suggesting that license proceeding for STP be 

stopped until waste confidence rulemaking finds in favor of concept of waste 

confidence

ML12356A233

1/3/13 Forthcoming meeting to discuss the DSEIS for the license renewal of STP, 

Units 1 and 2 

ML12342A397

1/10/13 Comment (6) of Javier Loera, on behalf of Ysleta del Sur Pueblo, on the NRC’s

environmental review of the effects of renewing the operating license for STP, 

Units 1 and 2

ML13030A445

1/11/13 Comment (2) of Sonia Santana on STP GEIS for license renewal ML13017A405

1/17/13 NRR e-mail capture regarding license renewal of STP, Units 1 and 2, located in 

Matagorda County, TX

ML13029A795

1/17/13 NRR e-mail capture regarding license renewal of STP, Units 1 and 2 ML13029A796

1/20/13 Comment (3) of John Elder on behalf on himself on notice of receipt and 

availability of application for renewal of facility operating license for STP, Units 1 

and 2

ML13025A357

1/21/13 Comment (4) of Cynthia Weehler on behalf of herself opposing notice of receipt 

and availability of application for renewal of facility operating license for STP, 

Units 1 and 2

ML13025A358

1/21/13 Comment (5) of Elizabeth Tobin on STPNOC, STP; notice of availability of draft 

supplement 48 to the GEIS for license renewal of nuclear plants

ML13025A359

1/21/13 STP, Units 1 and 2, update to LRA—environmental permits ML13032A074

1/29/13 NRR e-mail capture regarding NRC STP ML13036A306

1/29/13 NRR e-mail capture regarding draft for comment—license renewal of STP, 

Units 1 and 2, located in Matagorda County, TX

ML13029A797

1/30/13 DSEIS for license renewal of STP, Units 1 and 2 ML13029A469

1/31/13 NRR e-mail capture regarding STP—t-line maps for T&E review ML13036A305

2/7/13 Comment (7) of Kenneth Taplett on behalf of STPNOC on STP, notice of 

availability of draft supplement 48 to the GEIS for license renewal

ML13044A496

2/11/13 Revision of schedule for the conduct of environmental review of the STP LRA

(TAC Nos. ME5122, ME5123, ME4938, and ME939)

ML13011A131

2/15/13 RAI for the review of the STP LRA ML13037A678

2/21/13 Comment (8) of Stephen R. Spencer on behalf of U.S. Department of the Interior 

on STP application for renewal of facility operating license

ML13058A027

2/25/13 Summary of public meetings conducted on 1/15/13 to discuss DSEIS related to 

review of STP, Units 1 and 2, LRA

ML13023A334
Appendix E

E-9 

Date Correspondence Description ADAMS No.

3/1/13 NRR e-mail capture regarding EFH consultation with NRC for STP nuclear plant 

license renewal

ML13063A071

APPENDIX F 

NRC STAFF EVALUATION OF SEVERE ACCIDENT MITIGATION 

ALTERNATIVES

F-1 

F NRC STAFF EVALUATION OF SEVERE ACCIDENT MITIGATION 

ALTERNATIVES

F.1 Introduction

South Texas Project Nuclear Operating Company (STPNOC) submitted an assessment of 

severe accident mitigation alternatives (SAMAs) for the South Texas Project, Units 1 and 2, 

(STP) as part of its Environmental Report (ER) (STPNOC 2010). This assessment was based 

on the most recent STP probabilistic risk assessment (PRA) available at that time, a 

plant-specific offsite consequence analysis performed using the MELCOR Accident 

Consequence Code System 2 (MACCS2) computer code, and insights from the STP individual 

plant examination (IPE) and individual plant examination of external events (IPEEE) 

(HL&P 1992). In identifying and evaluating potential SAMAs, STPNOC considered SAMAs that 

addressed the major contributors to core damage frequency (CDF) and population dose at STP, 

as well as SAMA candidates found to be potentially cost beneficial in six other license renewal 

applications (LRAs). STPNOC initially identified a list of 21 potential SAMAs. This list was 

reduced to five unique SAMA candidates by eliminating SAMAs that are not applicable to STP 

for one or more of the following reasons:

• The SAMA has design differences at STP.

• The SAMAs have already been implemented at STP.

• The SAMA has estimated implementation costs that would exceed the dollar 

value associated with eliminating the severe accident risk at STP.

STPNOC assessed the costs and benefits associated with each of the potential SAMAs and 

concluded in the ER that none of the candidate SAMAs evaluated are potentially cost beneficial.

As a result of the review of the SAMA assessment, the U.S. Nuclear Regulatory Commission 

(NRC) staff (the staff) issued requests for additional information (RAIs) to STPNOC by letters 

dated May 31, 2011 (NRC 2011a), and September 1, 2011 (NRC 2011b), and in conference 

calls for clarification on July 28, 2011 (NRC 2011c), and January 31, 2012 (NRC 2012). Key 

questions concerned the following: 

• the historical development of the Level 1 and Level 2 PRA and model 

changes that most impacted CDF, 

• changes to STP design and operation since the version of the PRA used for 

the SAMA analysis (referred to as the STP_REV6 model, dated 2009), 

• differences between STP, Units 1 and 2, designs or operation and 

identification of shared systems, 

• the impact of open items and issues from the peer review of the PRA human 

reliability analysis (HRA), 

• the process used to map Level 1 results into the Level 2 analysis and to 

group containment event tree (CET) end states into release categories, 

• the selection of representative analysis cases, 

• population assumptions used in the Level 3 analysis, 

• the uncertainty analysis, 
Appendix F

F-2 

• the impact of new information on fire- and seismic-initiated sequences, and

• further information on the cost-benefit analysis of several specific candidate 

SAMAs and low cost alternatives. 

STPNOC submitted additional information by letters dated July 5, 2011 (STPNOC 2011a), 

August 23, 2011 (STPNOC 2011b), January 19, 2012 (STPNOC 2012a), and 

February 16, 2012 (STPNOC 2012b). In these responses to the RAIs, STPNOC provided: 

• a listing of the PRA model changes that had the most impact on CDF, 

• identification of design and operation changes since the freeze date and their 

impact on PRA results, 

• identification of design differences between units as well as shared systems, 

• identification and an assessment of the impact of open items and issues from 

the PRA reviews, 

• a discussion of the process for binning the source term release categories 

into release category groups, 

• clarification of the bases for selecting representative analysis cases for each 

release category group, 

• a discussion of the uncertainty analysis, 

• further details on the external events PRA models including the impact of new 

information on fire and seismic sequences, and 

• additional information regarding several specific SAMAs. 

STPNOC’s responses addressed the staff’s concerns and did not result in the identification of 

any potentially cost-beneficial SAMAs.

An assessment of the SAMAs for STP is presented in Sections F.2 through F.6.

F.2 Estimate of Risk for STP

STPNOC’s estimates of offsite risk at STP are summarized in Section F.2.1. The summary is 

followed by the staff’s review of STPNOC’s risk estimates in Section F.2.2.

F.2.1 STPNOC’s Risk Estimates

Two distinct analyses are combined to form the basis for the risk estimates used in the SAMA 

analysis. The first is the STP Level 1 and Level 2 PRA model, which reflects (a) the plant 

design configuration as of December 31, 2007, and (b) the plant data from January 1, 1998, 

through December 31, 2007, for component failure and equipment unavailability data

(STPNOC 2010). 

The second is a supplemental analysis of offsite consequences and economic impacts 

(essentially a Level 3 PRA model) developed specifically for the SAMA analysis. The SAMA 

analysis is based on the most recent STP Level 1 and Level 2 PRA model available at the time 

of the ER, referred to as the STP_REV6 model. The scope of the Level 1 model includes 

internal and external initiating events.

The STP CDF is approximately 6.4×10-6 per year for both internal and external events, as 

determined from quantification of the Level 1 PRA model. The CDF is based on the risk 
Appendix F

F-3 

assessment for internally initiated events, which includes internal flooding, and external events, 

which includes fire, seismic, external flooding, and tornado events. The internal events CDF is 

approximately 3.9×10-6 per year. The external events CDF is approximately 2.5×10-6 per year. 

The external events CDF includes contributions of approximately 1.0×10-6 per year due to fire 

events, 7.3×10-8 per year due to seismic events, and 1.4×10-6 per year due to other external 

events (STPNOC 2010). When determined from the sum of the CET sequences, or Level 2 

PRA model, the CDF is approximately 6.2×10-6 per year for both internal and external events. 

The 6.2x10-6 is used as the baseline CDF in the SAMA evaluations (STPNOC 2010).

Note that the above results, and those given in Tables F–1 through F–5, are based upon the 

STP model of record (STP_REV6) as presented in the ER (STPNOC 2010) and do not include 

STPNOC’s responses to RAIs. The RAIs consider the impact of new industry information 

concerning internal fire and seismic initiated events. The results relating to these RAIs are 

discussed in Sections F.2.2 and F.6.2.

The breakdown of CDF by initiating event is provided in Table F–1, Table F–2, Table F–3, and 

Table F–4 for internal, fire, seismic, and other external events, respectively (STPNOC 2011a). 

Table F–1 shows how internal events contribute about 61 percent of the total CDF. The largest 

contributors to the internal event CDF are two loss of offsite power (LOOP) events, “Loss of All 

Offsite Power” and “Loss of 345kV Offsite Power,” which contribute 15 percent and 10 percent, 

respectively, to the total CDF. 

Table F–2 shows how fire events make up the next largest contributor with about 16 percent 

contribution to the total CDF. “Fire Zone 047 Scenario X” and “Fire Zone 071 Scenario X” are 

the largest contributors with 6 percent and 3 percent contribution, respectively, to the total CDF. 

Table F–3 shows how seismic events make up a small contribution of about one percent to the 

total STP CDF. Seismic events with 0.4 g acceleration and 0.6 g acceleration are the largest 

contributors to the seismic event CDF, contributing 0.6 percent and 0.3 percent, respectively.

Table F–4 shows how other external events (excluding fire and seismic) make up the next 

largest contributor, adding up to about 22 percent of the total CDF. “Tornado Induced Failure of 

Switchyard and Essential Cooling Pond (ECP)” and “Essential Cooling Water (ECW) Failure 

due to Breach of Main Cooling Reservoir (MCR)” are the largest contributors, with 17 percent 

and 5 percent contribution, respectively, to the total CDF.

The STP Level 2 PRA model that forms the basis for the SAMA evaluation is an updated 

version of the IPE Level 2 model with the latest update incorporated in the 2005 Revision 

(STP_REV5). The Level 2 model is linked to the Level 1 model by passing the status of all top 

events previously evaluated in the Level 1 model. The Level 1 model includes the status of all 

systems needed for the Level 2 analysis. The CET, containing only phenomenological events, 

is then quantified using these inputs.

The CET considers the influence of physical and chemical processes on the integrity of the 

containment and on the release of fission products once core damage has occurred. The 

quantified CET sequences are binned into a set of end-states or release categories that are 

subsequently grouped into four major release groups that provide the input to the Level 3 

consequence analysis. The frequency of each major release group was obtained by summing 

the frequency of the individual accident progression CET endpoints (or release categories) that 

were binned (categorized) into the major release group. Source terms were developed for nine 

release categories using the results of Modular Accident Analysis Program (MAAP 4.0.5) 

computer code calculations. From these results, source terms were chosen to be 

representative of the four major release groups (STPNOC 2011a). The results of this analysis 

for STP are provided in Table F.3–2 of ER Attachment F (STPNOC 2010).
Appendix F

F-4 

Table F–1. STP Core Damage Frequency for Internal Events

Initiating event (a) CDF

(per year)

% Contribution to 

internal events 

CDF (b, c)

% Contribution to 

total CDF 

Loss of all offsite power 9.6×10-7 25 15

Loss of 345kV offsite power 6.3×10-7 16 10

Steam generator tube rupture (SGTR) 4.4×10-7 11 7

Excessive loss-of-coolant accident (LOCA) 3.2×10-7 8 5

Steam line break outside containment 2.8×10-7 7 4

Loss of electrical auxiliary building heating, 

ventilation and air conditioning (HVAC)

2.6×10-7 7 4

Turbine trip 1.8×10-7 5 3

Partial loss of main feedwater 1.5×10-7 4 2

Reactor coolant pump (RCP) seal LOCA 1.5×10-7 4 2

Interfacing system LOCA (ISLOCA) 1.3×10-7 3 2

Loss of DC busses 9.7×10-8 2 2

Small LOCAs 7.5×10-8 2 1

Reactor trip 6.5×10-8 2 1

Other internal events 3.6×10-7 9 6

Total CDF (internal events) 3.9×10-6 100 64 

(a) The impact of the sensitivity analysis to updated fire and seismic data on the total CDF is not included in these 

results. Section F.2.2 provides a discussion of these impacts.

(b) Obtained from CDF given in ER Table F.2-1 (STPNOC 2010) divided by the total internal events CDF of 3.89×10-6. (c) May not total to 100 percent due to round off.
Appendix F

F-5 

Table F–2. STP Core Damage Frequency for Fire Events

Fire initiator description (a) CDF 

(per year)

% Contribution 

to fire CDF (b, c)

% Contribution 

to total CDF (c)

Fire zone 047 scenario X 4.0×10-7 39 6

Fire zone 071 scenario X 2.1×10-7 21 3

Fire zone 047 scenario B 1.8×10-7 18 3

Control room fire scenario 18 1.2×10-7 12 2

Fire zone 047 scenario BC 6.4×10-8 6 1

Control room fire scenario 23 2.6×10-8 3 0.4

Fire zone 147 scenario O 1.1×10-8 1 0.2

Control room fire scenario 10 1.0×10-9 <1 <0.1

Total CDF (fire events) 1.0×10-6 100 16

(a) The impact of the sensitivity analysis to update fire and seismic data on the total CDF is not included in these 

results. Section F.2.2 provides a discussion of these impacts.

(b) Obtained from CDF given in ER Table F.2-1 (STPNOC 2010) divided by fire events CDF of 1.02×10-6. (c) May not total to 100 percent due to round off.

Table F–3. STP Core Damage Frequency for Seismic Events

Initiating event (a) CDF

(per year)

% Contribution to 

seismic CDF (b, c)

% Contribution to 

total CDF (c)

Seismic event, 0.4 g acceleration 4.1×10-8 55 0.6

Seismic event, 0.6 g acceleration 2.1×10-8 28 0.3

Seismic event, 0.2 g acceleration 9.8×10-9 13 0.2

Seismic event, 0.1 g acceleration 2.1×10-9 3 <0.1

Total CDF (seismic events) 7.3×10-8 100 1.1

(a) The impact of the sensitivity analysis to updated fire and seismic data on the total CDF is not included in these 

results. Section F.2.2 provides a discussion of these impacts.

(b) Obtained from CDF given in ER Table F.2-1 (STPNOC 2010) divided by seismic events CDF of 7.31×10-8. (c) May not total to 100 percent due to round off.
Appendix F

F-6 

Table F–4. STP Core Damage Frequency for Other External Events

Initiating event (a) CDF

(per year)

% Contribution to 

other external 

events CDF (b, c)

% Contribution to 

total CDF (c)

Tornado induced failure of switchyard and 

ECP

1.1×10-6 79 17

ECW failure due to breach of MCR 2.9×10-7 21 5

External flooding scenarios 2–6 9.5×10-9 <1 0.2

Flood induced LOOP 2.1×10-9 <1 <0.1

Total CDF (other external events) 1.4×10-6 100 22

(a) The impact of the sensitivity analysis to updated fire and seismic data on the total CDF is not included in these 

results. Section F.2.2 provides a discussion of these impacts.

(b) Obtained from CDF given in ER Table F.2-1 (STPNOC 2010) divided by other external events CDF of 1.41×10-6. (c) May not total to 100 percent due to round off.

The offsite consequences and economic impact analyses use the MACCS2 code to determine 

the offsite risk impacts on the surrounding environment and public. Inputs for these analyses 

include plant-specific and site-specific input values for core radionuclide inventory, source term 

and release characteristics, site meteorological data, projected population distribution (within a 

50-mi radius) for the year 2050, emergency response evacuation modeling, and economic data. 

The core radionuclide inventory is based on a plant-specific evaluation. The inventory 

corresponds to the end-of-cycle values for STP operating at a projected future 4,100 megawatts 

thermal (MWt). The current licensed power is 3,835 MWt (STPNOC 2010). The magnitude of 

the onsite impacts (in terms of cleanup and decontamination costs and occupational dose) is 

based on information provided in NUREG/BR-0184, Regulatory Analysis Technical Evaluation 

Handbook (NRC 1997a).

In the ER, the applicant estimated the dose risk to the population within 80-km (50-mi) of the 

STP site to be approximately 0.0174 person-Sievert (Sv) (1.74 person-roentgen equivalent man 

(rem)) per year. The breakdown of the total population dose by containment release mode is 

summarized in Table F–5. Large early releases are the dominant contributors (39 percent) to 

the population dose risk at STP. Small early releases (with pre-existing small containment 

failure) and late releases (with no sprays) are also significant contributors to the population dose 

risk.
Appendix F

F-7 

Table F–5. Breakdown of Population Dose by Containment Release Mode

Containment release mode

(major release category—RC) (a)

Population dose (personrem (b) per year) % Contribution 

RC I—large early releases (<3 hrs) 0.68 39

RC II—small early releases (<3 hrs) 0.59 34

RC III—late releases (>3 hrs) 0.42 24

RC IV—intact containment 0.05 3

Total 1.74 100

(a) The impact of the sensitivity analysis to updated fire and seismic data on the release category frequency is not 

included in these results. Section F.2.2 provides a discussion of these impacts.

(b) One person-rem=0.01 person-Sv. 

F.2.2 Review of STPNOC’s Risk Estimates

STPNOC’s determination of offsite risk at STP is based on the following three major elements of 

analysis:

(1) the Level 1 and 2 risk models that form the bases for the 2005 model (STP_REV5) 

reviewed by the NRC staff for the approval of the Risk Managed Technical 

Specification (RMTS) application, which is an updated version of the 1992 IPE 

submittal (HL&P 1992), which incorporated both internal and external events,

(2) the modifications to the STP_REV5 model that have been incorporated into the 

current STP PRA (STP_REV6), and

(3) the MACCS2 analyses performed to translate fission product source terms and 

release frequencies from the Level 2 PRA model into offsite consequence measures.

Each of these analyses was reviewed to determine the acceptability of STPNOC’s risk 

estimates for the SAMA analysis, as summarized below.

The first STP Level 1 PRA was completed in 1989 to support a request for revising certain STP 

technical specifications. This was subsequently updated and extended to incorporate a Level 2 

analysis, as documented in the STP IPE. The 1989 PRA and the IPE incorporated internal fires 

and all external events as well as internal event initiators. The internal events and fire events 

portions of the 1989 PRA were reviewed extensively as part of the technical specification 

change request approval (NRC 1994a). The NRC review of the IPE (NRC 1994b) concluded 

that the applicant met the intent of Generic Letter (GL) 88-20 (NRC 1988). Although no 

vulnerabilities were identified in the IPE, four improvements were identified. The ER indicated 

that all of these improvements have been implemented.

The internal events CDF value from the 1992 IPE (4.3×10-5 per year) is near the average of the 

values reported for other 4-loop Westinghouse plants. Figure 11.6 of NUREG-1560 

(NRC 1997b) shows that the IPE based total internal events CDF for 4-loop Westinghouse 

plants ranges from 3×10-6 per year to 2×10-4 per year, with an average CDF for the group of 

6×10-5 per year. It is recognized that other plants have updated the values for CDF subsequent 

to the IPE submittals to reflect modeling and hardware changes. The internal events CDF result 

for STP used for the SAMA analysis (6.4×10-6 per year) is somewhat lower than that for other 

plants of similar vintage. This is considered to be reasonable due to the unique design of STP, 

which uses three independent emergency core cooling system trains and four auxiliary 
Appendix F

F-8 

feedwater pumps as well as having a significant amount of physical separation of the redundant 

trains.

There have been many revisions to the original STP PRA model. The most relevant are the 

IPE, Revision STP_1999 and the subsequent revisions leading up to the current revision used 

in the SAMA assessment. A breakdown of the contributors to total CDF and a description of the 

changes made to the STP PRA, since the peer reviewed Revision STP_1999, were provided in 

response to NRC staff RAIs (STPNOC 2011a, 2011b). These changes are summarized in 

Table F–6. The STP_REV6 model reflects the current (as of the date of the ER submittal) STP 

configuration and design. In response to an RAI, STPNOC stated that a review of plant design 

and operation changes made since the last model update indicates that one modification will 

require a PRA model revision. STPNOC does not expect this change to have a significant 

effect on the SAMA evaluation (STPNOC 2011a). The staff reviewed the response and agreed 

with the applicant that the prospective change to the PRA model would not have a significant 

effect on the SAMA evaluation.

The STP PRA model is a single unit model rather than a model that incorporates explicit events 

in both units. In response to an RAI, STPNOC states that the STP, Units 1 and 2, are designed 

to be identical; therefore, the PRA model applies to both STP, Units 1 and 2 (STPNOC 2011a). 

However, STPNOC noted that there are two differences between Units 1 and 2 resulting from 

the phased implementation of design changes over several different refueling outages. One, 

involving load tap changers for engineered safety features transformers, was found to have less 

than a 0.5 percent increase in CDF and large early release frequency (LERF). The other, 

involving the addition of hand switches for the steam generator (SG) power operated relief 

valves in the control room, will exist for only a few months and is expected to result in a 

decrease in CDF and LERF (temporary modification to conservatively decrease CDF).
F-9 

Table F–6. STP PRA Historical Summary

PRA version Summary of significant changes 

from prior model

CDF (a)

(per year) 

Internal 

events

Seismic Fire External 

floods

Flood 

MCR

High 

wind 

IPE/IPEEE (b)

(1992)

Information from IPE/IPEEE report 

(HL&P 1992)

4.3×10-5 1.4×10-6 1.4×10-6 1.4×10-6 1.4×10-6 1.4×10-6 

STP_1999

(9/2001) 

2002 WOG peer review 8.8×10-6 7.3×10-8 1.4×10-6 1.4×10-8 2.9×10-7 1.1×10-6 

STP_REV4

(9/2003) 

Reviewed by the NRC staff for RMTS 

approval

Incorporated updated plant-specific 

train unavailability data, updated 

initiating events and component failure 

data

Incorporated latest operator error 

modeling and improved LOOP recovery 

modeling

Included safety injection accumulator 

modeling for large and medium LOCAs

Included hot leg recirculation modeling 

for Large LOCA

Removed credit for 150-ton air 

conditioning chillers

Improved modeling of support system 

initiating events

6.6×10-6 7.3×10-8 1.0×10-6 1.4×10-8 2.9×0-7 1.1×10-6 

STP_REV41 (c) Reviewed by the NRC staff for RMTS 

approval

Incorporated operator depressurization 

for small LOCA

Corrected modeling error for long-term 

6.6×10-6 NA NA NA NA NA 
 

F-10

PRA version Summary of significant changes 

from prior model

CDF (a)

(per year) 

Internal 

events

Seismic Fire External 

floods

Flood 

MCR

High 

wind 

response for medium LOCA

Requantified frequency for inadvertent 

opening of one or two pressurizer 

safety valves

Corrected conditional split fractions 

definitions to correct errors in basic 

event importance calculations

Re-binned several maintenance 

duration data variables to correct input 

problems with RISKMAN version being 

used

Split fault tree basic events containing 

several components to better reflect 

individual component importance.

STP_REV42 Reviewed by the NRC staff for RMTS 

approval

Corrected issues found during 

component risk ranking

NA NA NA NA NA NA 

STP_REV5

(9/2005) 

Reviewed by the NRC staff for RMTS 

approval

Incorporated plant modifications, 

procedure changes and data update 

through 2004

Incorporated modifications to Class IE 

vital AC system and main steam 

isolation valves

Level 2 update including containment 

capability analysis

Updated HRA to use of EPRI HRA 

7.7×10-6 7.3×10-8 9.7×10-7 1.4×10-8 2.9×10-7 1.1×10-6 
 

F-11

PRA version Summary of significant changes 

from prior model

CDF (a)

(per year) 

Internal 

events

Seismic Fire External 

floods

Flood 

MCR

High 

wind 

calculator 

STP_REV51 Added RMTS macros 7.7×10-6 7.3×10-8 9.7×10-7 1.4×10-8 2.9×10-7 1.1×10-6 

STP_REV6

(2009)

Updated equipment reliability data

Updated initiating event data

Updated planned maintenance data

Updated treatment of operator action 

for interfacing system LOCA

3.9×10-6 7.3×10-8 1.0×10-6 1.3×10-8 2.9×10-7 1.1×10-6 

(1/2012) (d) Updated fire analysis for impact of new 

information in NUREG/CR-6850 

(NRC 2005)

Updated seismic analysis for impact of 

2008 USGS seismic hazard 

(USGS 2008)

6.5×10-6 3.0×10-6 2.2×10-6 NA NA NA 

NA—Not available, and value would not impact SAMA Review

(a) All CDF values are point estimate values unless otherwise indicated.

(b) Total external events CDF is given as 3.2 percent of the total or 1.4×10-6 per year.

(c) Based on a response to an NRC staff RAI (STPNOC 2011a), which indicated that the CDF was higher than that for STP_REV4 by 1.2 

(d) Provided for information only. The PRA version is not considered a formal update. The CDF and LERF values were provided in resp

(STPNOC 2012a). All values are based on truncation value of 1×10-14 whereas prior results are based on a truncation value of 1×10-1

high winds are not explicitly provided but are not expected to change from prior values.
Appendix F

F-12

In response to the same RAI, STPNOC indicated that the only shared systems between units 

are the common switchyard, MCR, and the ECP (STPNOC 2011a). The NRC staff concludes 

that since there are no other shared systems, modeling of the other unit’s features is not 

required, and a single unit model is appropriate for the SAMA assessment.

The NRC staff noted that the STP PRA results (ER Table F.2–1) do not include any internal 

flooding initiated sequences. The NRC staff requested additional information (NRC 2011a), and 

STPNOC, in response, indicated that the high degree of separation between redundant 

divisions at STP resulted in all internal flooding sequences being screened out in the IPE and 

IPEEE (STPNOC 2011a). The NRC staff considered these sequences, as part of the RMTS 

review, discussed below. The staff concludes that the internal flood screening remains valid.

The NRC staff considered the peer reviews and other assessments performed for the STP PRA 

and the potential impact of the review findings on the SAMA evaluation. The most relevant of 

these are the 2002 peer review of the STP_1999 model, the STP self-assessment to the 

requirements of Regulatory Guide (RG) 1.200, An Approach for Determining the Technical 

Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities (NRC 2007a), 

and the NRC staff’s review of the STP models REV4, REV41, REV42, and REV5 in support of 

STPNOC’s RMTS application. STPNOC stated (STPNOC 2006) that the general assessment 

of the peer review was that the STP PRA could effectively be used to support applications 

involving risk significance determinations supported by deterministic analyses once the items 

noted in the element summaries and fact and observations (F&O) sheets were addressed. All 

F&O items were incorporated into STP_REV4, the original basis for the RMTS request, with two 

major exceptions. These exceptions were the Level 2 update and re-evaluation of the internal 

flood modeling. The resolutions of the F&Os associated with the two exceptions were 

incorporated into STP_REV5.

Revision 5 was performed to ensure that the STP PRA satisfies the requirements of Capability 

Category II of the American Society of Mechanical Engineers (ASME) PRA Standard 

(ASME 2002, 2003, 2005), as modified by RG 1.200, Appendix B. In response to an NRC RAI 

on the RMTS application, STPNOC provided information that described how the STP PRA 

meets the ASME criteria (STPNOC 2007). The HRA update, incorporated into Revision 5 of the 

PRA, was the subject of a follow-on peer review. As a result of the peer review, STPNOC found 

the F&Os from this review to not impact the RMTS application. In addition, these F&Os would 

be fully evaluated as part of the Revision 6 PRA (STPNOC 2007). In response to an RAI, 

STPNOC identified the content of the 10 Level A and B F&Os and stated that a preliminary 

review of the F&Os concluded that their resolution is not expected to have a significant impact 

on the STP PRA model or on the SAMA analysis (STPNOC 2011a).

The results of the NRC staff’s review of the STP PRA through Revision 5 are documented in a 

safety evaluation report (SER) appended to the NRC’s approval of the STP RMTS 

(NRC 2007a). The staff reviewed the scope and resolution of the 2002 peer review F&Os and 

concluded that the items were properly addressed by the applicant based on the documented 

resolutions. Based on the applicant’s assessments and the NRC staff’s reviews, the staff 

determined that the STP PRA internal events models met the requirements of RG 1.200, 

Revision 1, and were acceptable for the RMTS application.

Based on the following information, the NRC staff concludes that the internal events Level 1 

PRA model is of sufficient quality to support the SAMA evaluation: 

• The STP internal events PRA model has been peer-reviewed and the peer 

review findings were all addressed. 
Appendix F

F-13

• The model has been reviewed by the NRC staff as part of the RMTS 

application approval. 

• STPNOC has satisfactorily addressed NRC staff questions regarding the 

PRA. 

The STP PRA model includes seismic, fire, high winds, floods, and other external initiating 

events as well as internal initiating events. The updated external core damage results are 

described in ER Section F.2.1 and included in Table F–2 and Table F–3 along with the internal 

events results.

The STP IPEEE was submitted as part of the IPE in 1992 (HL&P 1992), in response to 

Supplement 4 of GL 88-20 (NRC 1991), and was based on the external events portion of the 

prior STP PRA submitted and reviewed by the NRC staff to support an STP license amendment 

(NRC 1994a). No fundamental weaknesses or vulnerabilities to severe accident risk concerning 

the external events were identified in the STP IPEEE. In a letter dated December 15, 1998 

(NRC 1998), the NRC staff stated that on the basis of the staff’s reviews of the PRA and IPEEE 

submittal, the staff concludes that the STP IPEEE process is capable of identifying the most 

likely severe accidents and severe accident vulnerabilities. Therefore, the STP IPEEE has met 

the intent of Supplement 4 to GL 88-20.

The STP IPEEE seismic analysis used a seismic PRA following NRC guidance (NRC 1991) and 

used the prior 1988 probabilistic safety assessment or PSA with enhancements recommended 

by the NRC guidance. The seismic PRA included a seismic hazard analysis, a fragility analysis, 

a plant logic analysis, and quantification of seismic CDF and various plant damage states.

The seismic hazard analysis estimated the annual frequency of exceedingly different levels of 

ground motion. The STP IPEEE used the Electric Power Research Institute (EPRI) 

(EPRI 1989) hazard curves and provided a sensitivity study result using the Lawrence 

Livermore National Laboratory (LLNL) (NRC 1989) curve. Four discrete accelerations (0.1 g, 

0.2 g, 0.4 g, and 0.6 g) were used to represent the full range of possible accelerations with point 

estimate values of the frequency for each acceleration determined from the mean exceedance 

frequency from the hazard curves.

The seismic fragility for safety-related structures, equipment, and components was determined 

from the results of an assessment of the median factor of safety against failure and its statistical 

variability under the safe-shutdown earthquake. System and fragility analysts supported the 

fragility analysis by plant walk downs. Fragilities for 2 structures and 18 components with 

median capacities less than 2.0 g were included in the model. Point estimate fragilities were 

then determined for each of the seismic initiating event accelerations evaluated.

The plant logic analysis determines the consequences of various structural and component 

failures in terms of CDF and release categories. A seismic failure event tree was used to 

represent the seismic failure impact of various plant components. The resulting seismic 

end-states were then inputted to support front line system trees that also consider non-seismic 

unavailabilities.

The seismic CDF resulting from the STP IPEEE was calculated to be 2×10-7 per year based on 

the EPRI hazard curve and 2×10-5 per year based on the LLNL hazard curve (HL&P 1992; 

NRC 1989). The current CDF value, based on the EPRI hazard curve, is 7×10-8 per year. The 

STP IPEEE did not identify any vulnerabilities due to seismic events or any potential 

improvements to reduce seismic risk.

In order to gain a perspective on the impact of the most recent USGS study of seismic hazard 

on the STP seismic risk, the NRC staff considered the analysis published for Generic Issue 199 
Appendix F

F-14

(NRC 2010). This analysis, using a simplified methodology and the 2008 USGS hazard curves 

(USGS 2008), gave a seismic CDF ranging from 9×10-7 to 6×10-6 per year for STP depending 

on spectral acceleration frequency (the peak ground acceleration or 10, 5, or 1 Hz). These 

results range from 8 to 14 times the corresponding seismic CDF value based on the EPRI 

hazard curves and used in the SAMA assessment in the ER.

In response to an NRC RAI (NRC 2011b), STPNOC updated the results of the seismic risk 

analysis to consider recent information for the determination of the seismic hazard frequency 

(STPNOC 2012a). The update considered the EPRI, LLNL, and the 2008 USGS hazard curves. 

In addition, STPNOC modified the seismic model to include:

• an increase in the number of seismic initiators from 4 to 6 to incorporate 

higher accelerations than in the original model to be compatible with the 

USGS hazard curves which extend to 2.1 g,

• the elimination of credit for a sequence specific recovery term that was 

non-conservatively applied in the STP_REV6 model, and

• an update to seismic fragility curves for many selected components based on 

a review of the original calculations and a plant walkdown associated with this 

update.

The result of this update yielded a seismic CDF of 3.0×10-6 per year based on the 2008 USGS 

hazard curves. The NRC staff considers these hazard curves to be the most current data 

available. The impact of these curves on the SAMA analysis was provided in response to the 

NRC RAI and is discussed further in Sections F.3.2 and F.6.2.

For SAMA sensitivity consideration, STPNOC has satisfactorily addressed RAIs regarding the 

seismic PRA (taking into account the 2008 USGS hazard curves, which are the most current 

data available). Hence, the NRC staff concludes that the updated seismic PRA model including 

the impact of the 2008 USGS seismic hazard curves provides an acceptable basis for 

identifying and evaluating the benefits of SAMAs.

The STP IPEEE fire analysis used a fire PRA following NRC guidance (NRC 1991) and 

represented an update of the previous 1988 PSA. These analyses involved a two-phase 

evaluation process—a spatial interaction analysis and the fire risk assessment. In the spatial 

interaction analysis, a large set of internal fire scenarios was identified and screened based on 

consideration of initiation frequency, spatial propagation, impact of mitigation, and the impact on 

components to plant safety. The resulting fire scenarios considered important were then 

analyzed in more detail. The resulting fire induced CDF of the unscreened areas was 

calculated to be 5×10-7 per year (NRC 1998).

The 1988 STP fire PSA was reviewed by Sandia National Laboratory (SNL). The SNL review 

concluded that the fire analysis was acceptable. This review was updated by the NRC staff in 

the review of the fire PRA contained in the STP IPEEE with the conclusion that the analysis 

examined the significant initiating events and dominant accident sequences for STP 

(NRC 1998). The IPE and IPEEE PRA was also used to support STPNOC’s request for 

changes in certain technical specifications, which was granted in 1994 (NRC 1994).

The fire analysis was subsequently updated in 1994 to address Thermolag® fire barrier 

performance. This fire analysis was supported by a comprehensive plant walkdown, in 

May 1994, by STP personnel. 

As part of the RMTS approval process, the applicant confirmed that all of the high-level 

requirements for a fire PRA, given in RG 1.200, Revision 1, are addressed in the STP fire PRA 

model and supporting documentation. In response to a staff concern regarding the screening of 
Appendix F

F-15

fire sequences for the RMTS application, the applicant determined that there were no screened 

sequences that should be included in the PRA model used for the RMTS application 

(STPNOC 2007).

The NRC staff’s RMTS SER states that, based on STPNOC’s submittal and the staff’s focused 

reviews, the STP PRA fire model addresses the technical characteristics and attributes of these 

elements, identified in RG 1.200, Revision 1, as they relate to issues that could impact the fire 

model’s adequacy for implementation of RMTS. Therefore, the staff finds that the STP PRA fire 

model is acceptable for the RMTS application (NRC 2007a).

The NRC staff noted that the STP fire PRA may underestimate fire risk since it does not 

incorporate the latest guidance in NUREG/CR-6850, EPRI/NRC-RES Fire PRA Methodology for 

Nuclear Power Facilities (NRC 2005), and requested that STPNOC assess the impact of this 

updated guidance on the SAMA analysis (NRC 2011a). In response to this RAI, STPNOC 

provided the results of an assessment of the impact of the information and insights contained in 

NUREG/CR-6850 (NRC 2005) concerning fire ignition frequencies, hot short probabilities, and 

fire non-suppression probabilities on the eight non-screened fire scenarios included in the 

STP_REV6 model (STPNOC 2012a). This assessment yielded a modified fire initiated CDF of 

2.2×10-6 per year, which is about 2.2 times higher than that used in the SAMA analysis. The 

impact of this modified fire CDF on the SAMA analysis is discussed in Sections F.3.2 and F.6.2.

Based on the following information, the NRC staff concludes that the fire PRA model, modified 

to address new information and insights contained in NUREG/CR-6850 (NRC 2005), provides 

an acceptable basis for identifying and evaluating the benefits of SAMAs: 

• the STP fire PRA model has been updated since the IPEEE, 

• the updated fire PRA was reviewed by the NRC staff for the RMTS 

application, and 

• STPNOC has satisfactorily addressed NRC staff RAIs regarding the fire PRA.

The STP IPE and IPEEE analysis of high winds, floods, and other external events was based on 

the analysis in the 1988 PSA. A wide range of external events was considered; however, no 

vulnerabilities were identified in the STP IPEEE due to high winds, floods, and other external 

events.

For high winds, the STP design is such that critical structures can withstand winds in excess of 

360 mph without major damage. The frequency of tornado winds in excess of 360 mph was 

determined to be 8×10-9 per year. Since there is considerable safety margin in the design, 

failures would not be expected until wind speeds exceed the design value. Tornado missiles 

were also considered and the associated risk found to be small.

The likelihood of the ECW intake structure being clogged by debris generated by tornados, 

hurricanes, or MCR failure were investigated with the dominant contribution being from 

tornadoes. The frequency of tornadoes that cause blockage and failure of the switchyard was 

found to be 1.2×10-6 per year (initiating frequency), leading to the currently assessed CDF of 

1.1×10-6 per year.

External flooding of the STP site due to storms, offsite dam breaks, and onsite dam breaks were 

considered and evaluated in the STP IPE and IPEEE. Of all the sources affecting plant safety, 

the source of greatest importance was found to be the MCR. Many scenarios due to MCR 

failure that resulted in impacts to various plant equipment were evaluated with the most 

important being MCR failure leading to ECW failure. The current MCR failure frequency is 

3.2×10-7 per year (MCR failure rate), leading to the currently assessed CDF of 2.9×10-7 per year.
Appendix F

F-16

A review of transportation and nearby facility accidents confirmed that there were no severe 

accident vulnerabilities from these accidents (transportation and nearby facility external events). 

The total contribution to CDF from these other non-fire and non-seismic external events is 

1.4×10-6 per year.

For the STP RMTS license amendment approval, the NRC staff also reviewed the external 

events modeled in the STP PRA and found that the data and assumptions applied were 

reasonable and conservative. Based on the applicant’s submittals and the staff reviews, the 

staff concluded that the STP PRA external events models complied with the guidance of 

RG 1.200, Revision 1, and was acceptable for the RMTS application (NRC 2007b).

Given that the STP IPEEE external events PRA model has been reviewed by the NRC staff, 

that the current model has been reviewed by the NRC staff as part of the RMTS approval, and 

that STPNOC has satisfactorily addressed NRC staff questions regarding the PRA, the NRC 

staff concludes that the external events Level 1 PRA model, combined with the results of the 

analysis of the impacts of new fire and seismic information, is of sufficient quality to support the 

SAMA evaluation.

The NRC staff reviewed the general process used by STPNOC to translate the results of the 

Level 1 PRA into containment releases, as well as the results of the Level 2 analysis, as 

described in the ER and in response to NRC RAIs (STPNOC 2011a). As indicated above, the 

Level 2 STP PRA model that forms the basis for the SAMA evaluation is essentially an updated 

version of the IPE model.

The Level 2 analysis is linked to the Level 1 model by extending the model to include the CET, 

which characterizes the accident phenomena. The CET considers the influence of physical and 

chemical processes on the integrity of the containment and on the release of fission products 

once core damage has occurred. Conditions specifically considered on entry into the CET 

include reactor pressure at the time of core damage, steam generator heat removal, availability 

of water in the reactor cavity, containment isolation and bypass status, containment spray 

operation, containment heat removal, and the initiating event.

The STP CET addresses events occurring prior to vessel breach (including the potential for 

in-vessel recovery), the phenomena associated with both in-vessel and ex-vessel accident 

progression, containment integrity challenges, and the potential for containment failure. The 

quantified CET sequences result in 63 possible end-states (or release categories) based on 

combinations of reactor coolant system conditions at the time of vessel breach, the availability 

of water to cool the core debris, the availability of containment spray, and the mode and timing 

of containment failure. These release categories are then combined into the four major release 

groups: I—large early release, II—small early release, III—late release, and IV—intact 

containment (STPNOC 2011a). The 15 highest frequency release categories that contribute to 

the major release groups are described in Table F.3-5 of the ER, Attachment F 

(STPNOC 2010).

Source terms were developed by the applicant for eight release categories using the results of 

MAAP 4.0.5 computer code calculations (STPNOC 2011a). The source term for the intact 

release category were estimated from the Wolf Creek SAMA submittal, which is acceptable to 

the NRC staff based on both the Wolf Creek and STP plants being Westinghouse 4-loop PWR 

plants and the intact containment release category being a small contributor to the total 

population dose risk. The results of these analyses for STP are provided in Table F.3-2 of the 

ER, Attachment F (STPNOC 2010).

Representative source terms for each of the four major release groups were then selected from 

the source terms for the nine release categories. This was done by reviewing the relevant 
Appendix F

F-17

accident frequencies and release characteristics and selecting the representative accident 

sequence and source term that was considered the one that best represented how a change in 

major release group frequency would be reflected in terms of consequence. The representative 

sequences and source terms selected for the major release groups are identified along with 

consequence results in Table F.3-6 of the ER, Attachment F (STPNOC 2010).

In the ER, the applicant validated the selection of representative source terms for the major 

release groups by recalculating the base case consequences using the set of nine release 

categories, for which source terms were available, with their associated frequencies instead of 

the four major release groups. As shown in ER Table F.3-8, the total dose-risk consequence 

(person-rem per year) is identical to that using the representative source terms for the four 

major release groups. The resulting offsite economic consequence risk (dollars per year) is 

about 18 percent higher; however, this would only increase the maximum averted cost-risk 

(MACR), which is discussed in Section F.6.1, by about 1.5 percent, which the applicant 

considered a very minor change (within acceptable SAMA sensitivity consideration by the staff).

In an RAI, the NRC staff stated that while the reduced set of four representative sequences 

provided essentially the same result as using the full set of nine sequences, this would not 

necessarily be true for the cost-benefit analysis of individual SAMAs (NRC 2011a). Since the 

source terms for the representative sequences are not necessarily those that would yield the 

largest consequence, any SAMA that impacted a release category frequency whose source 

term is higher than that for the selected representative sequence would have its benefit 

underestimated. In response to the RAI, STPNOC provided a sensitivity analysis using the 

most conservative relevant available source term for each of the nine major release categories. 

The result was an increase in population dose risk of over 300 percent to 0.0532 person-Sv per 

year (5.32 person-rem per year) and a corresponding increase in offsite economic cost risk of 

over 400 percent. However, while the results showed that selecting alternate conservative 

source terms for the consequence analysis significantly increases the benefit of the SAMAs 

evaluated, the conclusions of the SAMA analysis were unchanged (STPNOC 2011a). This is 

discussed further in Section F.6.2.

The ER notes that some of the MAAP source term release fractions were still increasing based 

on calculation times of 24 to 48 hours. A sensitivity case was run with the releases extrapolated 

to 72 hrs. The resulting population dose risk increased by 5 percent, and the offsite economic 

cost risk increased by 3 percent.

As indicated above, the current STP Level 2 PRA model is an update of the model used in the 

IPE. No vulnerabilities were identified in the IPE back-end (i.e., Level 2) analysis. Risk-related 

insights and improvements discussed in the IPE submittal were discussed previously. The NRC 

staff and contractor review of the IPE Level 2 analysis concluded that the applicant has made 

reasonable use of the PSA techniques in performing the back-end analysis and that the 

techniques employed are capable of identifying severe accident vulnerabilities (NRC 1994b).

The LERF model was included in the Westinghouse Owner’s Group (WOG) peer review 

discussed previously, and all F&Os have been resolved (STPNOC 2007). The NRC staff’s 

review of the RMTS application concluded that all F&Os (including those pertaining to LERF) 

were properly addressed. As stated previously, the staff concluded that the internal events PRA 

satisfied the guidance of RG 1.200, Revision 1 (NRC 2007b).

Based on the NRC staff’s review of the Level 2 methodology, the staff finds that STPNOC has 

adequately addressed NRC staff RAIs, that the LERF model has been peer reviewed and all 

F&Os resolved, and that the LERF model was recently reviewed and found to be in 

conformance with RG 1.200 and the ASME PRA standard. 
Appendix F

F-18

Based on these findings and the results of the sensitivity analysis, which showed that the 

conclusions of the SAMA analysis are not changed by using the full set of nine release 

categories, the NRC staff concludes that the Level 2 PRA provides an acceptable basis for 

evaluating the benefits associated with various SAMAs.

STPNOC used the MACCS2 code and a core inventory from a plant-specific calculation to 

determine the offsite consequences of activity release (STPNOC 2010). STPNOC indicated 

that the core inventory was generated using ORIGEN2.1 based on a conservative projected 

future power of 4,100 MWt for STP.

The NRC staff reviewed the process used by STPNOC to extend the containment performance 

(Level 2) portion of the PRA to an assessment of offsite consequences (essentially a Level 3 

PRA). This included consideration of the source terms used to characterize fission product 

releases for the applicable containment release categories and the major input assumptions 

used in the offsite consequence analyses. Plant-specific input to the code includes the source 

terms for each source term category and the reactor core radionuclide inventory (both 

discussed above), site-specific meteorological data, projected population distribution within an 

80-km (50-mi) radius for the year 2050, emergency evacuation modeling, and economic data. 

This information is provided in Section F.3 of Attachment F to the ER (STPNOC 2010).

All releases were modeled as being from the top of the reactor building. The thermal content of 

each of the releases was assumed to be the same as ambient (a non-buoyant plume). 

Sensitivity analyses were performed for the elevation and thermal content of the releases. 

Decreasing the release height from the top of the reactor building to ground level and 

25 percent, 50 percent, and 75 percent of containment height decreased the population dose 

risk by 1 to 2 percent and offsite economic cost risk by 2 to 7 percent. Increasing the release 

heat to 1 and 10 MW for each plume segment increased the population dose risk by 0 to 

3 percent and the offsite economic cost risk by 2 to 7 percent. Building wake effects were also 

investigated by increasing and decreasing the wake size by a factor of two. The population 

dose risk showed no change, and the offsite economic cost risk either showed no change or 

increased by 1 percent. The NRC staff notes that previous SAMA analyses have shown only 

minor sensitivities to release height, buoyancy, and building wake effects. Based on the 

information provided, the staff concludes that the release parameters used are acceptable for 

the purposes of the SAMA evaluation. 

STPNOC used site-specific meteorological data for the 2006 calendar year as input to the 

MACCS2 code. The development of the meteorological data is discussed in Section F.3.5 of 

Attachment F to the ER. The data were collected from the onsite meteorological monitoring 

system and the National Weather Service measurements at nearby Palacios Municipal Airport. 

Missing meteorological data were first filled in from the onsite backup tower. Gaps in onsite 

data were filled in from the hourly data at the Palacios Municipal Airport. Remaining data gaps 

were to be filled in by (in order of preference) using corresponding data from the primary tower 

60-meter level (taking the relationship between the levels as determined from immediately 

preceding hours), interpolation (if the data gap was less than 4 hours), or using data from the 

same hour and a nearby day of a previous year. A sensitivity analysis of available data of 

record was completed using MACCS2 and the meteorological data for the years 2006 and 2008 

and found that data for the year 2006 resulted in the largest dose and economic cost risk and 

this was used for the baseline cost-benefit analysis as appropriate. The population dose risk 

decreased by 0 to 7 percent and the offsite economic cost decreased by 2 to 11 percent for 

years 2008 and 2007, respectively. An additional sensitivity case was completed for rainfall in 

the last spatial segment. The base case assumed rainfall at all times. The sensitivity study 

allowed the rainfall to follow the onsite meteorology. The resulting population dose risk 

decreased by 23 percent, and the offsite economic cost risk decreased by 35 percent. The 
Appendix F

F-19

NRC staff notes that previous SAMA analyses results have shown little sensitivity to 

year-to-year differences in meteorological data and concludes that the use of the 2006 

meteorological data in the SAMA analysis is reasonable.

The population distribution used by the applicant as input to the MACCS2 analysis was based 

on the year 2000 census data from an updated study for the potential construction of additional 

units (STPNOC 2009). County growth rates were applied to obtain the year 2050 population 

(Texas State Data Center 2006). In response to an NRC RAI, the applicant stated that the total 

population in year 2000 for the SAMA analysis was 1.4 percent higher than the SECPOP2000 

values presented in Section 2.6.1 of the ER (STPNOC 2011a). This was due to the updated 

study using a population based on the construction of additional units that is not included in the 

SECPOP2000 data. SECPOP2000 is a computer coded developed for the NRC by Sandia 

National Laboratories to calculate the population within 20 and 50 miles of the site. In the RAI 

response, STPNOC also provided the year 2050 rosette population distribution. The transient 

population within the emergency planning zone (EPZ), was included in the residential population 

data for year 2000 and projected to year 2050 (STPNOC 2011a). STPNOC further clarified that 

the sector multipliers for the major metropolitan areas within the 50-mi radius included any 

expected high growth rates based on the county-weighted population projections 

(STPNOC 2011a). The NRC staff considers the methods and assumptions for estimating 

population reasonable and acceptable for purposes of the SAMA evaluation.

The emergency evacuation model was modeled as a single evacuation zone extending out 

16 km (10 mi) from the plant (the EPZ). The applicant assumed that 95 percent of the

population would evacuate. This assumption is conservative relative to the NUREG-1150 study 

(NRC 1990), which assumed evacuation of 99.5 percent of the population within the EPZ. The 

evacuated population was assumed to move at an average radial speed of approximately 

1.34 meters per second (mps) (3.0 mph) with a delayed start time of 60 minutes after 

declaration of a general emergency for one-half the population. The evacuation speed was 

projected to conditions associated with year 2050 by conservatively assuming that all of the 

roads in 2007 transported traffic at their maximum throughput and that no new roads would be 

constructed. In response to an NRC RAI, the applicant clarified that the year 2007 evacuation 

study population was based on the exponential growth rate from year 2000 to year 2050 

(STPNOC 2011a). Transient population was not calculated separately. A general emergency 

declaration was assumed to occur when plant conditions degraded to a point where it was 

judged that there was a credible risk to the public, based on STP emergency action levels. 

Times for declaration of emergency are presented in Table F.3-4 of the ER. A sensitivity study 

was completed where the delayed population was increased and decreased by a factor of two. 

The population dose risk increased and decreased by 1 percent, respectively, and the offsite 

economic cost risk showed no change. Another sensitivity study was performed for the 

evacuation speed, where the speed was increased and decreased by a factor of two. The

increased evacuation speed resulted in a population dose risk decrease by 1 percent and no 

change in offsite economic cost risk. The decreased evacuation speed resulted in a population 

dose risk increase of 2 percent and no change in offsite economic cost risk. The NRC staff 

concludes that the evacuation assumptions and analysis are reasonable and acceptable for the 

purposes of the SAMA evaluation.

SECPOP2000 (NRC 2003) was used to access site-specific agriculture and economic data from 

the 1997 National Census of Agriculture for each of the counties surrounding STP to a distance 

of 80 km (50 mi). The data file accessed by SECPOP2000 for that information was modified to 

correct two errors in the issued version. These errors are generally known as the missing notes 

parameter error and the missing county numbers error. In response to an NRC RAI, the 

applicant clarified that a third error associated with column formatting of regional economic data 
Appendix F

F-20

was also corrected (STPNOC 2011a). Region-wide wealth data (i.e., farm wealth and non-farm 

wealth) were also based on county-weighted averages for the region within 80 km (50 mi) of the 

site using data in the 1997 National Census of Agriculture, as accessed by SECPOP2000. In 

addition, generic economic data that applied to the region as a whole, as described in 

Section F.3.3 of the ER, were revised from the MACCS2 sample problem input in order to 

account for cost escalation since 1986 (the year the input was first specified). An escalation 

factor of 1.94, representing cost escalation from 1986 to January 2009, was applied to 

parameters describing cost of evacuating and relocating people, land decontamination, and 

property condemnation.

The NRC staff concludes that the methodology used by STPNOC to estimate the offsite 

consequences for STP, combined with the results of the sensitivity analysis associated with the 

selection of representative source terms, provides an acceptable basis from which to proceed 

with an assessment of risk reduction potential for candidate SAMAs. Accordingly, the NRC staff 

based its assessment of offsite risk on the CDF and offsite doses reported by STPNOC.

F.3 Potential Plant Improvements

The process for identifying potential plant improvements, an evaluation of that process, and the 

improvements evaluated in detail by STPNOC are discussed in this section.

F.3.1 Process for Identifying Potential Plant Improvements 

STPNOC’s process for identifying potential plant improvements (SAMAs) consisted of the 

following elements: 

• review of the most significant split fractions from the current, plant-specific 

PRA, 

• review of potential plant improvements identified in the STP IPE and IPEEE,

• review of cost-beneficial SAMA candidates identified in LRAs for six other 

nuclear power plant sites, and

• review of generic SAMA candidates from Nuclear Energy Institute 

(NEI) 05-01 (NEI 2005) to identify SAMAs that might address areas of 

concern in the STP PRA.

Based on this process, an initial set of 21 candidate SAMAs, referred to as Phase I SAMAs, 

were identified. In Phase I of the evaluation, STPNOC performed a qualitative screening of the 

initial list of SAMAs and eliminated SAMAs from further consideration using the following 

criteria: 

• The SAMA is not applicable to STP due to design differences.

• The SAMA has already been implemented at STP or would achieve results 

that have already been achieved at STP by other means.

• The SAMA has estimated implementation costs that would exceed the dollar 

value associated with eliminating all severe accident risk at STP.

Based on this screening, 16 SAMAs were eliminated, leaving 5 SAMAs for further evaluation. 

The results of the Phase I screening analysis are shown in Table F.5-3 of Attachment F to the 

ER. The remaining SAMAs, referred to as Phase II SAMAs, are listed in Table F.6-1 of

Attachment F to the ER (STPNOC 2010). In Phase II, a detailed evaluation was performed for 

each of the five remaining SAMA candidates, as discussed in Sections F.4 and F.6.
Appendix F

F-21

F.3.2 Review of STPNOC’s Process 

STPNOC’s efforts to identify potential SAMAs included explicit consideration of potential SAMAs 

for both internal and external events since the STP PRA incorporates all initiating events 

including internal, fire, seismic, high winds, and floods. The initial list of SAMAs generally 

addressed the hardware considered to be important to CDF and release category frequency 

from risk reduction worth (RRW) perspectives at STP and included selected SAMAs from prior 

SAMA analyses for other plants.

STPNOC provided a tabular listing of the Level 1 PRA split fractions sorted according to their 

RRW (STPNOC 2010). SAMAs impacting these split fractions would have the greatest potential 

for reducing risk. STPNOC initially identified a RRW cutoff of 1.24, which corresponds to about 

a 24 percent change in CDF given 100-percent reliability of the SAMA. This equates to a 

benefit of approximately $50,000 for a single unit or $100,000 for both units. This is stated to be 

the minimum implementation cost associated with a procedure change. The applicant indicated 

that, at this cutoff, only two split fractions would need to be assessed for potential SAMAs. 

Since this would only provide limited insights into potential SAMAs, STPNOC extended the 

Level 1 importance review to include the top 40 split fractions, which corresponds to a RRW 

of 1.022. This is the equivalent of a two-unit benefit of approximately $11,000. All split fractions 

in the Level 1 listing were reviewed to identify potential SAMAs and all were addressed by one 

or more SAMAs (STPNOC 2010).

STPNOC also provided and reviewed the top 40 Level 2 PRA split fractions, corresponding to a 

RRW of 1.027, for the release categories contributing over 97 percent of the population 

dose-risk and over 99 percent of the offsite economic cost risk. Major release categories I 

(large-early), II (small early), and III (late) were included in this assessment. The Level 2 split 

fractions for release Category IV (containment intact) were not included in the review to prevent 

split fractions unimportant to dose and cost risk from biasing the importance listing. All split 

fractions in the Level 2 listing were reviewed to identify potential SAMAs, and all were 

addressed by one or more SAMAs (STPNOC 2010).

As a result of the review of the Level 1 and Level 2 split fractions, 15 SAMAs were identified. 

The applicant reviewed the cost-beneficial Phase II SAMAs from prior SAMA analyses for five 

Westinghouse PWR sites and one General Electric BWR site. The applicant’s review identified 

six additional SAMAs. It was determined that the other Phase II SAMAs reviewed were already 

represented by a SAMA identified from the importance list reviews, have low potential for risk 

reduction at STP (i.e., do not address split fractions on the importance lists), or were not 

applicable to STP.

The NRC staff noted that three SAMAs that were found to be cost beneficial at Prairie Island, 

were not addressed by STPNOC. Similarly, three SAMAs were found to be cost beneficial at 

Indian Point, were not addressed by STPNOC (NRC 2011a). STPNOC responded to an RAI 

indicating that the SAMAs in question had either (a) been implemented at STP or (b) the cost of 

implementing at STP exceeded the STP MACR (STPNOC 2011a), which justifies the screening 

of the SAMAs. The staff agrees with this assessment.

Wolf Creek SAMA 13, “provide an alternate fuel oil tank with gravity feed capability,” was 

considered already implemented at STP by an existing capability that requires a pump. The 

NRC staff noted that this has less capability than a gravity system and asked STPNOC to 

further justify the screening of this SAMA. In response to the RAI, STPNOC provided additional 

information on fuel oil storage at STP. The current STP fuel oil transfer system uses a gravity 

feed line between the fuel oil storage tank and the standby diesel generator (SBDG). Each 

SBDG is supplied from its own dedicated storage tank with a 7-day fuel oil supply. The system 
Appendix F

F-22

described in the disposition of this SAMA is necessary only to refill these dedicated fuel oil 

storage tanks (STPNOC 2011a).

SAMA 16, “provide a portable engine driven instrument air compressor,” was identified from a 

review of industry cost-beneficial SAMAs and was screened out on the basis of having an 

excessive cost. The basis for this SAMA was Prairie Island SAMA 22, which used nitrogen 

bottles rather than a portable air compressor. In response to a staff RAI to consider this lower 

cost alternative, the applicant indicated that loss of instrument air was not identified as a 

significant contributor to STP risk (STPNOC 2011a). There is only one instrument air split 

fraction with a RRW greater than 1.000. Its RRW of 1.016 corresponds to an averted cost-risk 

of $8,100, which would not result in a cost-beneficial SAMA using nitrogen bottles even at the 

95th percentile CDF.

STPNOC considered the potential plant improvements described in the STP IPE (HL&P 1992), 

which included both internal and external events, in the identification of plant-specific candidate 

SAMAs. As a result of the review of the IPE, four improvements were identified and are listed in 

Section F.5.1.4 of Attachment F of the ER. The review of the IPE did not lead to any additional 

SAMA candidates since the four improvements identified in the IPE have already been 

implemented at STP (STPNOC 2010).

The applicant also considered the potential for cost-beneficial SAMAs that address the external 

event contributors screened out in the IPE and IPEEE because of “low risk.” For each of the 

screened initiator types, a potential averted cost-risk (PACR) was determined based on an 

estimate of the event occurrence frequency and assuming that the PACR is proportional to this 

frequency compared to the CDF. The PACR for each of the seven screened event types is 

given in Section F.5.1.5 of the ER. All are less than the minimum implementation cost for the 

site of $100,000 associated with a procedure change. This assessment includes internal floods, 

which were screened out in the IPE and IPEEE. In response to an NRC RAI, the applicant 

indicated that a review of the internal flood screening was performed in support of the RMTS 

license amendment with the conclusion that the earlier screening remained valid 

(STPNOC 2011a).

In response to an NRC RAI, the applicant clarified that the generic list of industry-based SAMA 

candidates provided in NEI 05-01 (NEI 2005) was used as an idea source to generate SAMAs 

for the important contributors identified from the STP PRA (STPNOC 2011a).

As discussed in Section F.2.2, in response to an NRC RAI, STPNOC provided an assessment 

of the impact of updated information concerning fire and seismic risks on the overall STP risk. 

The postulated fire and seismic changes affect the risk profile and increase the maximum 

possible benefit if all risks were eliminated. Because of these changes, the importance analysis 

review for the identification of candidate SAMAs and the screening of potential SAMAs was 

redone. This reassessment is documented in Tables 8, 9 and 10 of the January 19, 2012, 

submittal (STPNOC 2012a). One additional SAMA (SAMA 1a—install a “seismic safe” system) 

was identified. This SAMA is similar to SAMA 1 and includes earthquake resistant heat removal 

systems that could operate in the event of a seismically induced station blackout (SBO). This 

SAMA was screened as having an excessive cost.

Based on this information, the NRC staff concludes that the set of SAMAs evaluated in the ER, 

together with those identified in response to NRC staff RAIs, addresses the major contributors 

to both internal and external event CDF.

The NRC staff questioned the applicant about potentially lower cost alternatives to some of the 

SAMAs evaluated (NRC 2011a, 2012a), including:
Appendix F

F-23

• alternate SAMA(s) for sequences that are mitigated by SAMA 1 but do not 

need tornado protection; 

• use of the Technical Support Center (TSC) diesel generator (DG) to both 

supply the positive displacement pump (PDP) and support auxiliary feedwater 

(AFW) operation; 

• installing an alternate intake structure for the ECW either in the ECP or the 

MCR that would minimize the likelihood of debris preventing ECW cooling or 

using temporary and portable pumps with a movable suction that could 

provide water to the ECW system; and

• strengthening the ECW pump seismic restraints, which was identified as 

limiting in the fragility update, in lieu of installing the complex “seismic safe” 

system (STPNOC 2012a).

In response to the RAIs, the applicant addressed the suggested lower cost alternatives and 

determined that they were either not feasible or were not cost beneficial 

(STPNOC 2011a, 2012b). This is discussed further in Section F.6.2.

The NRC staff notes that the set of SAMAs submitted is not all-inclusive since additional, 

possibly even less expensive, design alternatives can always be postulated. However, the NRC 

staff concludes that the benefits of any additional modifications are unlikely to exceed the 

benefits of the modifications evaluated and that the alternative improvements would be unlikely 

to cost less than the least expensive alternatives evaluated when the subsidiary costs 

associated with maintenance, procedures, and training are considered.

The NRC staff concludes that STPNOC used a systematic and comprehensive process for 

identifying potential plant improvements for STP, and the set of SAMAs evaluated in the ER, 

together with those evaluated in response to NRC staff inquiries, is reasonably comprehensive 

and, therefore, acceptable. This search included reviewing insights from the STP plant-specific 

risk studies that included internal initiating events as well as fire, seismic, and other external 

initiated events, and reviewing plant improvements considered in previous SAMA analyses.

F.4 Risk Reduction Potential of Plant Improvements

In the ER, the applicant evaluated the risk-reduction potential of the five SAMAs that were not 

screened out in the Phase I analysis and retained for the Phase II evaluation. The SAMA 

evaluations were performed using realistic assumptions with some conservatism.

STPNOC used model re-quantification to determine the potential benefits for each SAMA. The 

CDF, population dose, and offsite economic cost reductions were estimated using the STP 

STP_REV6 PRA model. The changes made to the model to quantify the impact of SAMAs are 

detailed in Section F.6 of Attachment F to the ER (STPNOC 2010). Table F–7 lists the 

assumptions considered to estimate the risk reduction for each of the evaluated SAMAs, the 

estimated risk reduction in terms of percent reduction in CDF and population dose, and the 

estimated total benefit (present value) of the averted risk. The estimated benefits reported in 

Table F–7 reflect the combined benefit in both internal and external events. The determination 

of the benefits for the various SAMAs is further discussed in Section F.6.

The impact of SAMA 10, “enhance procedures to ensure the SGs are filled or maintained filled 

in SGTR events to scrub fission products,” was modeled by reassigning the SGTR CDF 

contribution for Release Categories I (7.48x10-9 per year) and III (1.35x10-7 per year) to Release 

Categories II and IV, respectively. In response to an NRC RAI regarding the source of these 

values, the applicant indicated that because SAMA 10 is dependent on the availability of 
Appendix F

F-24

secondary side makeup, only a fraction of SGTR scenarios are relevant to the SAMA 10 

evaluation. The relevant frequencies were obtained from an examination of the PRA model’s 

results (STPNOC 2011a).

The NRC staff noted that the evaluation of SAMA 12, “enhance procedures to prevent clearing 

of RCS cold leg water seals,” did not consider the condition in which non-condensable gases 

such as hydrogen are present since this condition is not modeled in the PRA. Additionally, the 

staff noted that SBO sequences were excluded in the modeling of this SAMA because AC

power is needed to start an RCP. The staff asked STPNOC to assess whether these potential 

non-conservatisms impact the SAMA analysis (NRC 2011a). In response to the RAI, the 

applicant clarified that the scenario leading to hydrogen gas generation condition is represented 

conservatively in the induced SGTR event scenarios. The sequences for the scenarios are 

included in the assessment of SAMA 12 (STPNOC 2011a). The applicant further clarified that 

excluding the SBO sequences is appropriate because:

(a) Induced SGTR is not an issue for SBO scenarios in which offsite power is recovered 

in time to prevent core damage.

(b) Plant procedures do not instruct the operators to start the RCPs for SBO scenarios in 

which offsite power is restored only after core damage.

For these reasons, the applicant concluded that the evaluation of SAMA 12 is not 

underestimated.

The NRC staff has reviewed STPNOC’s bases for calculating the risk reduction for the various 

plant improvements and concludes, with the above clarifications, that the rationale and 

assumptions for estimating risk reduction are reasonable and generally conservative (i.e., the 

estimated risk reduction is higher than what would actually be realized). Accordingly, the NRC 

staff based its estimates of averted risk for the various SAMAs on STPNOC’s risk reduction 

estimates.

F.5 Cost Impacts of Candidate Plant Improvements

STPNOC estimated the costs of implementing the 21 Phase I SAMAs through the development 

of site-specific cost estimates and use of other applicants’ estimates for similar improvements. 

The costs were developed on a site basis (i.e., two units). If the cost estimate was for a single 

unit based on other applicants’ estimates for similar improvements, the cost estimate was 

multiplied by two to derive the costs on a site basis. The site-specific cost estimates did not 

include (a) contingency cost (unexpected implementation obstacles) or (b) the cost of 

replacement power during extended outages required to implement the modifications 

(STPNOC 2010). This approach is in accordance with NEI 05-01 and conservative. The cost 

estimates based on other applicants’ estimates did not account for inflation, which is also 

conservative.

In response to an NRC RAI regarding the source of the cost estimates, the applicant replied that 

the scope and definition of the SAMA were initially developed by the PRA analyst and then 

reviewed and modified by the STP design staff to account for any plant-specific issues that 

could interfere with or improve the SAMA design. The major cost contributors were then 

identified, and their cost magnitudes were estimated by the design engineers (cost estimating is 

a normal part of STPNOC’s design engineers’ functions as appropriate) (STPNOC 2011a).

The NRC staff reviewed the applicant’s cost estimates, presented in Table F-6.1 of 

Attachment F to the ER in response to NRC RAIs (STPNOC 2011a). For certain improvements, 

the NRC staff compared the cost estimates to estimates developed elsewhere for similar 
Appendix F

F-25

improvements, including estimates developed as part of other applicants’ analyses of SAMAs, 

for operating reactors.

The NRC staff noted that the estimated cost of $7.6M for SAMA 17a, “install Westinghouse 

RCP shutdown seals,” is higher than other estimates for Westinghouse improved seals such as 

the estimate by Tennessee Valley Authority for Watts Bar Unit 2 of $1.1M (TVA 2010). In 

response to the RAI, STPNOC indicated that the STP RCP seal design is different from that 

used at Watts Bar and other Westinghouse plants (STPNOC 2011a). Because of this unique 

design, STP would incur an entire new seal design and associated engineering costs while the 

other plants would be able to spread the costs over a larger number of units. STPNOC 

provided the details of the STP cost estimate, which included engineering, procedure revision, 

modified seal housing, new seals, and installation. The NRC staff notes that even with some 

cost savings that might be possible, not included in STPNOC’s estimate, the cost is expected to 

be well above the Watts Bar estimate and the STP MACR. The NRC staff considers STPNOC’s 

justification for the cost of implementing SAMA 17a reasonable.

The NRC staff also noted that the estimated cost of $4.5M for SAMA 14, “provide capability to 

cross-tie emergency 4 KV divisions on a single unit,” seems high given that an inter-unit 

cross-tie is already available. In response to the RAI, the applicant stated that the original intent 

of SAMA 14 was to provide the capability to perform the cross-tie between emergency 4 KV AC 

buses within a unit rapidly enough to prevent an RCP seal LOCA. The most effective means for 

achieving this capability was a direct bus-to-bus connection, which does not currently exist at 

STP. An indirect path is, however, available through an emergency transformer using existing 

hardware. Using this path would require significant engineering and procedure development 

costs due to the potential for creating single failure potential among multiple divisions of 

equipment. While the estimated costs for the work associated with this alternative is not cost 

beneficial, STPNOC also notes that the available time to prevent RCP seal failure is such that 

navigating through the procedures and implementing the cross-tie in time to prevent seal failure 

is unlikely (STPNOC 2011a). The NRC staff considers STPNOC’s justification for the cost of 

implementing SAMA 14 reasonable.

In response to an NRC RAI (STPNOC 2011a), the applicant provided the details of the cost 

estimates for two SAMAs: SAMA 3b, “install fire wrap on PDP cables in cable spreading room,” 

and SAMA 11, “modify fire protection system to supply containment spray headers.” The 

detailed cost estimate for SAMA 11 supports the cost used and the conclusion in the SAMA 

analysis (as discussed in the response). For SAMA 3b, the applicant estimated the engineering 

portion of the cost to be $250,000 per unit, which appears high to the NRC staff. The staff notes 

that this estimated cost may be valid due to the need to identify the PDP cables (as explained 

by the applicant). Furthermore, if the engineering costs were reduced by $50,000 per unit, the 

resulting total cost of $700,000 ($800K minus 2x$50K) is still well above the benefit reported for 

this SAMA (see Table F–7). The NRC staff concludes that, with the above clarifications, the 

cost estimates provided by STPNOC are sufficient and appropriate for use in the SAMA 

evaluation.
F-26

Table F–7. SAMA Cost-Benefit Screening Analysis for STP

SAMA (a) Assumptions

% Risk reduction Total ben

CDF Population 

dose 

Baseline 

(internal + 

external)

B

u

3b (c)—Install fire wrap on PDP cables 

in cable spreading room

Eliminate failure of the PDP due to a fire in 

the cable spreading room

<1 <1 3K 7

4—Develop procedures to isolate 

CCW inside containment

eliminate failure of the operator action to 

isolate CCW

2 10 27K 7

10—Enhance procedures to ensure 

the SGs are filled or maintain filled in 

SGTR events to scrub fission products

Reassign a portion of the SGTR CDF 

contribution for the large early release 

category (7.48E-06 per year) and late 

release category (1.35E-07 per year) to 

the small early release category and intact 

containment release category, respectively

0 2 3K 8

12—Enhance procedures to prevent 

clearing of RCS cold leg water seals

Reassign the induced SGTR CDF 

contribution (2.4E-09 per year) for 

sequences in which offsite power is 

available from the large early release 

category to the intact containment release 

category

0 0 <1K <

13—Develop procedures to open 

doors or use portable fans for alternate 

SBDG room cooling or both

Eliminate failure of the operator action to 

provide SBDG room cooling

<1 0 1K 3

15—Develop emergency procedures 

for alternate essential ECWIS room 

cooling

Eliminate failure of the operator action to 

provide ECWIS room cooling

1 2 8K 2

(a) The impact of the sensitivity analysis to updated fire and seismic data is not included in these results. Section F.6.2 provides a discuss

(b) Based on the response to NRC staff RAI 1.d (STPNOC 2011b), the NRC staff increased the baseline benefits by a factor of 2.7 to acco

(c) SAMA 3b retained as a Phase II SAMA based on the results of the uncertainty analysis.
Appendix F

F-27

F.6 Cost–Benefit Comparison

STPNOC’s cost-benefit analysis and the NRC staff’s review are described in the following 

sections.

F.6.1 STPNOC’s Evaluation 

The methodology used by the applicant was based primarily on NRC’s guidance for performing 

cost-benefit analysis (i.e., NUREG/BR-0184 (NRC 1997a)). The guidance involves determining 

the net value for each SAMA according to the following formula:

Net Value = (APE + AOC + AOE + AOSC) − COE 

where:

APE = present value of averted public exposure ($)

AOC = present value of averted offsite property damage costs ($)

AOE = present value of averted occupational exposure costs ($)

AOSC = present value of averted onsite costs ($)

COE = cost of enhancement ($)

If the net value of a SAMA is negative, the cost of implementing the SAMA is larger than the 

benefit associated with the SAMA, and it is not considered cost beneficial. STPNOC’s 

derivation of each of the associated costs is summarized below.

NUREG/BR-0058 has been revised to reflect the NRC’s policy on discount rates. Revision 4 of 

NUREG/BR-0058 states that two sets of estimates should be developed, one at 3 percent and 

one at 7 percent (NRC 2004). The applicant provided a base set of results using the 3 percent 

discount rate and a sensitivity study using the 7 percent discount rate (STPNOC 2010).

Averted Public Exposure (APE) Costs

The APE costs were calculated using the following formula:

APE = Annual reduction in public exposure (Δ person-rem per year)

x monetary equivalent of unit dose ($2,000 per person-rem)

x present value conversion factor (15.04 based on a 20-year period 

with a 3-percent discount rate)

As stated in NUREG/BR-0184 (NRC 1997a), it is important to note that the monetary value of 

the public health risk after discounting does not represent the expected reduction in public 

health risk due to a single accident. Rather, it is the present value of a stream of potential 

losses extending over the remaining lifetime, in this case, the renewal period, of the facility. 

Thus, it reflects the expected annual loss due to a single accident, the possibility that such an 

accident could occur at any time over the renewal period, and the effect of discounting these 

potential future losses to present value. For the purposes of initial screening, which assumes 

elimination of all severe accidents due to internal and external events, the applicant calculated 

an APE of approximately $52,300 for the 20-year license renewal period (STPNOC 2010).

Averted Offsite Property Damage Costs (AOC)

The AOCs were calculated using the following formula:

AOC = Annual CDF reduction

x offsite economic costs associated with a severe accident (on a per event 

basis) 

x present value conversion factor
Appendix F

F-28

For the purposes of initial screening, which assumes all severe accidents due to internal and 

external events are eliminated, the applicant calculated an annual offsite economic risk of about 

$1,600 based on the Level 3 risk analysis. This results in a discounted value of approximately 

$24,400 for the 20-year license renewal period (STPNOC 2010).

Averted Occupational Exposure (AOE) Costs

The AOE costs were calculated using the following formula:

AOE = Annual CDF reduction

x occupational exposure per core damage event

x monetary equivalent of unit dose

x present value conversion factor

The applicant derived the values for averted occupational exposure from information provided in 

Section 5.7.3 of the NUREG/BR-0184 (NRC 1997a). Best estimate values provided for 

immediate occupational dose (3,300 person-rem) and long-term occupational dose (20,000 

person-rem over a 10-year cleanup period) were used. The present value of these doses was 

calculated using the equations provided in the handbook in conjunction with a monetary 

equivalent of unit dose of $2,000 per person-rem, a real discount rate of 3 percent, and a time 

period of 20 years to represent the license renewal period. For the purposes of initial screening, 

which assumes all severe accidents due to internal and external events are eliminated, the 

applicant calculated an AOE of approximately $4,000 for the 20-year license renewal period 

(STPNOC 2010).

Averted Onsite Costs

Averted onsite costs (AOSC) include averted cleanup and decontamination costs and averted 

power replacement costs. Repair and refurbishment costs are considered for recoverable 

accidents only and not for severe accidents. The applicant derived the values for AOSC based 

on information provided in Section 5.7.6 of NUREG/BR-0184 (NRC 1997a).

The applicant divided this cost element into two parts—the onsite cleanup and decontamination 

cost, also commonly referred to as averted cleanup and decontamination costs, and the 

replacement power cost.

Averted cleanup and decontamination costs (ACC) were calculated using the following formula:

ACC = Annual CDF reduction

x present value of cleanup costs per core damage event

x present value conversion factor

The total cost of cleanup and decontamination subsequent to a severe accident is estimated in 

the NUREG/BR-0184 (NRC 1997a) to be $1.5x109 (undiscounted). This value was converted to 

present costs over a 10-year cleanup period and integrated over the term of the proposed 

license extension. For the purposes of initial screening, which assumes all severe accidents 

due to internal and external events are eliminated, the applicant calculated an ACC of 

approximately $124,500 for the 20-year license renewal period (STPNOC 2010).

Long-term replacement power costs (RPC) were calculated using the following formula: 

RPC = Annual CDF reduction

x present value of replacement power for a single event

x factor to account for remaining service years for which replacement power 

is required
Appendix F

F-29

x reactor power scaling factor

The applicant based its calculations on the rated STP net electric output of 

1,365 megawatt-electric (MWe) per unit and scaled up from the 910 MWe reference plant in 

NUREG/BR-0184 (NRC 1997a). Therefore, the applicant applied a power-scaling factor of 

1,365/910 (or STP net electric output divided by reference plant output) to determine the 

replacement power costs. For the purposes of initial screening, which assumes all severe 

accidents due to internal and external events are eliminated, STPNOC calculated an RPC of 

approximately $53,000 and an AOSC of approximately $178,000 for the 20-year license 

renewal period (STPNOC 2010).

Using the above equations, the applicant estimated the total present dollar value equivalent 

associated with eliminating severe accidents from internal and external events at STP to be 

about $258,200 for a single unit, rounded to $259,000. Because all SAMA costs and benefits 

were provided on a site basis, the applicant doubled this value to obtain the two-unit site value 

of $518,000. This represents the dollar value associated with eliminating severe accident risks 

for all internal and external events at the two STP units (referred to as the maximum averted 

cost-risk (MACR)).

STPNOC’s Results

If the implementation costs for a candidate SAMA exceeded the calculated benefit, the SAMA 

was considered not to be cost beneficial. In the baseline analysis contained in the ER (using a 

3 percent discount rate), STPNOC identified no potentially cost-beneficial SAMAs. STPNOC 

also did not identify any potentially cost-beneficial SAMAs even after consideration of analysis 

uncertainties.

F.6.2 Review of STPNOC’s Cost-Benefit Evaluation 

The cost-benefit analysis performed by STPNOC was based primarily on NUREG/BR-0184 

(NRC 1997a) and discount rate guidelines in NUREG/BR-0058 (NRC 2004). The analysis was 

executed consistently with this guidance. No SAMAs were determined to be cost beneficial in 

STPNOC’s baseline analysis in the ER.

The applicant considered the impact that possible increases in benefits from analysis 

uncertainties would have on the results of the SAMA assessment. In the ER, STPNOC 

presents the results of an uncertainty analysis of the internal and external events CDF for STP, 

which indicates that the 95th percentile value is a factor of 1.6 greater than the mean CDF for 

STP. The applicant considered whether any additional Phase I SAMAs might be retained for 

further analysis if the MACR is increased by a factor of 1.6. One such SAMA was identified—

SAMA 3b, “install fire wrap on PDP cables in cable spreading room.”

The applicant also considered the impact on the Phase II analysis if the estimated benefits from 

internal and external events were increased by the 1.6 uncertainty factor. The additional 

Phase I SAMA—SAMA 3b—was included in this sensitivity analysis. No SAMAs became cost 

beneficial in STPNOC’s analysis (STPNOC 2010).

In Section F.7.1 of the ER, the total CDF of 6.39×10-6 per year is described as being the mean 

from the RISKMAN Monte Carlo quantification. In response to the NRC RAI on the uncertainty 

analysis, STPNOC provided further information describing how the analysis was performed. 

Since the quantification of the complete STP Level 1 PRA results in a large number of 

sequences, for which an uncertainty analysis is impractical, a reduced set of sequences is used. 

The results of the Monte Carlo analysis were then scaled so that the mean of the distribution 
Appendix F

F-30

matched the mean of the CDF point estimates. The total CDF of 6.39×10-6 per year is, 

therefore, a point estimate (STPNOC 2011a).

In response to an NRC RAI (NRC 2011a), STPNOC provided an uncertainty analysis that 

indicated the 95th percentile CDF for the reduced set of sequences used is 1.59×10-5 per year 

while the mean CDF and point estimate CDF for these sequences are 8.52×10-6 per year and 

5.89×10-6 per year, respectively. The uncertainty multiplier was then revised to be the ratio of 

the 95th percentile CDF to the point estimate, both for the reduced set of sequences, or 

1.59×10-5 divided by 5.89×10-6 or 2.7 (STPNOC 2011b). The applicant considered whether any 

additional Phase I SAMAs might be retained for further analysis if the MACR is increased by a 

factor of 2.7. No additional SAMAs were identified.

The applicant also considered the impact on the Phase II analysis if the estimated benefits from 

internal and external events were increased by the 2.7 uncertainty factor. No SAMAs became 

cost beneficial in STPNOC’s analysis (STPNOC 2011b).

The NRC staff noted that the original 1.6 uncertainty ratio developed for STP appeared to be 

low considering the larger uncertainty bands associated with external events. The applicant

responded that, with the exception of seismic initiating events, probability distributions for all 

initiating events were included in the Monte Carlo uncertainty analysis and that use of point 

estimates for the seismic sequences was considered justified because of the small seismic CDF 

contribution (STPNOC 2011a). However, as discussed in Section F.2.2, the seismic CDF may 

be considerably larger than that used in the cost-benefit analyses presented in the ER. 

Based on the following information, the NRC staff considers the use of the 2.7 uncertainty 

multiplier for the SAMA analysis. This is consistent with the guidance provided in NEI 05-01 

and acceptable: 

• STPNOC’s revised analysis used the higher uncertainty factor of 2.7, which is 

generally higher than the 95th percentile uncertainty factor used in other 

SAMA analyses. 

• STPNOC performed a separate assessment of the impact of the higher 

seismic CDF on the SAMA analysis. 

• The increased uncertainty in seismic risk would not be expected to impact the 

benefit of SAMAs not specifically addressing seismic failures.

STPNOC provided the results of additional sensitivity analyses in the ER, including use of a 

7 percent discount rate and variations in MACCS2 input parameters. These analyses did not 

identify any additional potentially cost-beneficial SAMAs (STPNOC 2010).

As discussed in Section F.2.2, the selection of representative sequences and associated source 

terms to be used for the four major release categories could yield non-conservative risk 

benefits. In response to an NRC RAI, the applicant provided the results of a sensitivity analysis 

that used the most conservative relevant available source term for each of the nine major 

release categories (STPNOC 2011a). STPNOC revised the baseline analysis using the 

conservative source terms (using a 3 percent discount rate) and identified no potentially 

cost-beneficial SAMAs. The NRC staff also increased the revised baseline benefits by a factor 

of 2.7 to account for uncertainties and identified no potentially cost-beneficial SAMAs. The 

results for the revised baseline and revised baseline with uncertainty are provided in Table F–8. 
Appendix F

F-31

Table F–8. SAMA Cost-Benefit Screening Analysis for 

STP Using Conservative Source Terms

SAMA

Total benefit ($)

Cost ($)

Conservative 

source terms 

revised baseline 

(internal + 

external)

Conservative 

source terms 

revised baseline 

with 

uncertainty(a)

3b—Install fire wrap on PDP cables in cable 

spreading room

7K 18K 800K

4—Develop procedures to isolate CCW inside 

containment

35K 94K 100K

10—Enhance procedures to ensure the SGs are 

filled or maintain filled in SGTR events to scrub 

fission products

30K 80K 100K

12—Enhance procedures to prevent clearing of 

RCS cold leg water seals

<1K <1K 100K

13—Develop procedures to open doors or use 

portable fans for alternate SBDG room cooling or 

both

4K 10K 100K

15—Develop emergency procedures for alternate 

ECWIS room cooling

14K 38K 100K

(a) Based on the response to NRC RAI 1.d (STPNOC 2011b), the NRC staff increased the revised baseline benefits 

by a factor of 2.7 to account for uncertainties.

SAMAs identified primarily on the basis of the internal events analysis could provide benefits in 

certain external events, in addition to their benefits in internal events. Since the STP_REV6 

PRA model is an integrated internal and external events model, STPNOC’s evaluation 

accounted for the potential risk reduction benefits associated with both internal and external 

events.

As discussed in Section F.2.2, the NRC staff asked STPNOC to assess the impact of the 

updated fire and seismic information on the SAMA analysis (NRC 2011a). In this analysis, 

STPNOC revised the baseline analysis using the updated fire and seismic information and 

increased these revised baseline analyses by 2.7 to account for uncertainties (using a 3 percent 

discount rate) and identified no potentially cost-beneficial SAMAs. The NRC staff also 

increased these revised benefits to account for the conservative source terms and identified no 

potentially cost-beneficial SAMAs. The results of these analyses are provided in Table F–9. 
Appendix F

F-32

Table F–9. SAMA Cost-Benefit Screening Analysis for 

STP Using Updated Fire and Seismic Risk Analysis and Conservative Source Terms

SAMA

Total benefit ($)

Cost ($)

Updated fire and 

seismic risk 

assessment 

(internal + 

external) with 

uncertainty(a)

Updated fire and 

seismic risk 

assessment 

(internal + external) 

with uncertainty(a)

and conservative 

source terms(b)

3b—Install fire wrap on PDP cables in cable 

spreading room

18K 44K 800K

4—Develop procedures to isolate CCW inside 

containment

71K 94K 100K

10—Enhance procedures to ensure the SGs are 

filled or maintain filled in SGTR events to scrub 

fission products

8K 84K 100K

12—Enhance procedures to prevent clearing of 

RCS cold leg water seals

3K 4K 100K

13—Develop procedures to open doors or use 

portable fans for alternate SBDG room cooling or 

both

16K 51K 100K

15—Develop emergency procedures for 

alternate ECWIS room cooling

22K 41K 100K

(a) Baseline benefits increased by a factor of 2.7 to account for uncertainties (STPNOC 2012a, 2012b).

(b) The impact of conservative source terms is obtained from the results provided in Table 2-11 of the July 5, 2011, 

submittal (STPNOC 2011a) compared with the results of the original submittal (STPNOC 2010).

As indicated in Section F.3.2, the NRC staff asked the applicant to evaluate potentially lower 

cost alternatives to the SAMAs considered in the ER (NRC 2011a), as summarized below:

• SAMA 1, “involving using a portable AC generator for long term AFW support 

and protecting the Technical Support Center (TSC) emergency diesel 

generator (EDG) from tornado events,” was identified as a means of 

mitigating a large number of important basic events. While the tornado 

protection is important for high wind initiated sequences, many other 

sequences would be mitigated without the cost of the tornado protection. 

STPNOC provided the results of a cost estimate that did not include the costs 

associated with the tornado protection. The revised cost of $2.4 million is 

much larger than the MACR; hence, such an alternative was determined not 

to be cost beneficial (STPNOC 2011a).

• An additional alternate to SAMA 1 would be to use the TSC DG to both 

supply the PDP and support AFW operation rather than requiring a portable 

AC generator. STPNOC provide the results of a cost estimate for this 

alternative. The revised cost of $1.9 million remains above the MACR; 

hence, this alternative was determined not to be cost beneficial 

(STPNOC 2011a).
Appendix F

F-33

• The tornado induced failure of the switchyard and emergency cooling pond 

could be mitigated by installing an alternate intake structure for the ECW 

either in the ECP or the MCR that would minimize the likelihood of debris 

preventing ECW cooling or using a temporary and portable pumps with a 

movable suction that could provide water to the ECW system. In response to 

the RAI, STPNOC provided the results of a cost estimate for a large surface 

area debris cage as a less costly alternative to an additional intake structure. 

This cost was $828,000, which is approximately equal to the 95th percentile 

MACR. The cost for the even less costly portable truck-mounted pump 

alternative was given as $350,000. While less than the MACR, this cost is 

more than the benefit associated with eliminating the tornado initiated 

sequence (17 percent of the total CDF), or $143,000 at the 95th percentile; 

hence, this alternative was determined to not be cost beneficial 

(STPNOC 2011a).

• Strengthening ECW pump seismic restraints was identified as an alternative 

to the SAMA 1a “seismic safe” system. While not mitigating all seismically 

induce SBOs, it is potentially less costly than the complex “seismic safe” 

system. STPNOC assessed the benefit of eliminating the risk to ECW pump 

seismic failures using the Fussell-Vesely importance results and found the 

benefit to be $54,000 using the 2.7 uncertainty multiplier. However, it is not 

cost beneficial because it is less than the minimum SAMA implementation 

cost (for procedure changes) of $100,000 (STPNOC 2012b). If adjusted to 

incorporate the potential impact of the more conservative source terms, the 

NRC staff estimates that the benefit could be somewhat greater 

than $100,000. However, based on the expected cost of strengthening the 

seismic restraints, which would involve replacing 24 seismic bolts deeply 

imbedded in concrete, and that the analysis conservatively assumes all of the 

risk would be eliminated by replacing the seismic bolts, the NRC staff

concludes that this alternative is unlikely to be cost beneficial.

As indicated in Section F.4, the NRC staff questioned STPNOC on the risk reduction potential 

for certain SAMAs (NRC 2011a, 2011b). In response to the RAIs, STPNOC addressed each 

SAMA and addressed the staff’s concerns.

The NRC staff concludes that the costs of all of the SAMAs evaluated would be higher than the 

associated benefits.

F.7 Conclusions

STPNOC compiled a list of 21 SAMAs based on a review of the most significant split fractions 

from the plant-specific internal and external event PRA, insights from the plant-specific IPE, 

cost-beneficial SAMAs from LRAs for other plants, and review of other industry documentation. 

An initial qualitative screening removed SAMA candidates that:

• modified features not applicable to STP due to design differences, 

• were determined to have already been implemented at STP or would achieve 

results that have already been achieved at STP by other means, or 

• have estimated implementation costs that would exceed the dollar value 

associated with completely eliminating all severe accident risk at STP. 
Appendix F

F-34

Based on this screening, 16 SAMAs were eliminated, leaving 5 candidate SAMAs for 

evaluation.

For the remaining SAMA candidates, a cost-benefit analysis was performed, with the results 

shown in Table F–7. The cost-benefit analyses showed that none of the SAMA candidates 

were potentially cost beneficial in the baseline analysis. STPNOC performed additional 

analyses to evaluate the impact of parameter choices and uncertainties on the results of the 

SAMA assessment. In this process, one additional SAMA was identified for detailed 

cost-benefit analysis. However, additional analyses did not result in the discovery of any of the 

SAMA candidates being potentially cost beneficial.

The NRC staff reviewed the STPNOC analysis and concludes that the methods used, and the 

implementations of those methods, were sound. The treatment of SAMA benefits and costs 

supports the general conclusion that the SAMA evaluations performed by STPNOC are 

reasonable and sufficient for the license renewal submittal.

The staff concurs with STPNOC’s conclusion that none of the candidate SAMAs are potentially 

cost beneficial. This conclusion is based on the generally conservative treatment of costs and 

benefits. This conclusion is consistent with the low residual level of risk indicated in the STP 

PRA and the fact that STPNOC has already implemented the plant improvements identified 

from the IPE and IPEEE.

F.8 References

10 CFR Part 50. Code of Federal Regulations, Title 10, Energy, Part 50, “Domestic Licensing of 

Production and Utilization Facilities.”

10 CFR Part 51. Code of Federal Regulations, Title 10, Energy, Part 51, “Environmental 

protection regulations for domestic licensing and related regulatory functions.”

10 CFR Part 54. Code of Federal Regulations, Title 10, Energy, Part 54, “Requirements for 

Renewal of Operating Licenses for Nuclear Power Plants.”

10 CFR Part 100. Code of Federal Regulations, Title 10, Energy, Part 100, “Reactor Site 

Criteria.”

[ASME] American Society of Mechanical Engineers. 2002. “Standard for Probabilistic Risk 

Assessment for Nuclear Power Plant Applications.” ASME RA-S-2002, April 5, 2002.

[ASME] American Society of Mechanical Engineers. 2003. “Addenda to ASME RA-S-2002, 

Standard for Probabilistic Risk Assessment for Nuclear Power Plant Applications.” ASME 

RA-Sa-2003, December 5, 2003.

[ASME] American Society of Mechanical Engineers. 2005. “Addenda to ASME RA-S-2002, 

Standard for Probabilistic Risk Assessment for Nuclear Power Plant Applications.” ASME 

RA-Sb-2005, December 30, 2005.

[EPRI] Electric Power Research Institute. 1989. “Probabilistic Seismic Hazard Evaluations at 

Nuclear Plant Sites in the Central and Eastern United States; Resolution of the Charleston 

Earthquake Issues.” EPRI NP-6395-D, EPRI Project P101-53, Palo Alto, CA. April 1989.

[HL&P] Houston Lighting and Power Company. 1992. “South Texas Project Electric 

Generating Station Level 2 Probabilistic Safety Assessment and Individual Plant Examination.” 

August 1992. ADAMS No. ML0617001702, ML0617001790, ML0617001850.

[NEI] Nuclear Energy Institute. 2005. Severe Accident Mitigation Alternative (SAMA) Analysis 

Guidance Document, NEI 05-01 (Rev. A). Washington, D.C. November 2005.
Appendix F

F-35

[NRC] U.S. Nuclear Regulatory Commission. 1988. Generic Letter 88-20, “Individual Plant 

Examination for Severe Accident Vulnerabilities.” November 23, 1988. ADAMS 

No. ML031150465

[NRC] U.S. Nuclear Regulatory Commission. 1989. Seismic Hazard Characterization of 

69 Nuclear Plant Sites East of the Rocky Mountains. Washington DC: NRC. 

NUREG/CR-5250, Volume 5. 1989.

[NRC] U.S. Nuclear Regulatory Commission. 1990. Severe Accident Risks: An Assessment 

for Five U.S. Nuclear Power Plants—Final Summary Report. Washington DC: NRC. 

NUREG-1150, Volume 1. 1990.

[NRC] U.S. Nuclear Regulatory Commission. 1991. Individual Plant Examination of External 

Events (IPEEE) for Severe Accident Vulnerabilities. Washington, DC: NRC. Generic Letter 

No. 88-20, Supplement 4. June 28, 1991. ADAMS No. ML031150485

[NRC] U.S. Nuclear Regulatory Commission. 1994a. Letter from Suzanne C. Black, Director, to 

William T. Cottle, Houston Lighting & Power Company. Subject: “Issuance of Amendment 

Nos. 59 and 47 to Facility Operating License Nos. NPF-76 and NPF-80 and Related Relief 

Request—South Texas Project, Units 1 and 2 (TAC Nos. M76048 and M76049).” 

February 17, 1994. ADAMS No. ML021300134.

[NRC] U.S. Nuclear Regulatory Commission. 1994b. Memorandum to: Steven A. Varga 

(USNRC-NRR) to M. Wayne Hodges (USNRC-RES), Subject: Review of South Texas Project 

Individual Plant Examination (IPE) Submittal—Internal Events. December 1994.

[NRC] U.S. Nuclear Regulatory Commission. 1997a. Regulatory Analysis Technical Evaluation 

Handbook. Washington, DC: NRC. NUREG/BR-0184. ADAMS No. ML050190193.

[NRC] U.S. Nuclear Regulatory Commission (NRC). 1997b. Individual Plant Examination 

Program: Perspectives on Reactor Safety and Plant Performance. Washington, DC: NRC. 

NUREG-1560. ADAMS No. ML063550244, ML063550228, and ML063470259. 

[NRC] U.S. Nuclear Regulatory Commission. 1998. Letter from Thomas W. Alexion, U.S. NRC, 

to William T. Cottle, STP Nuclear Operating Company. Subject: Review of south Texas 

Project, Units 1 and 2 Individual Plant Examination of External Events (IPEEE) Submittal (JAC 

Nos. M83676 and M83677). Washington, D.C. December 15, 1998.

[NRC] U.S. Nuclear Regulatory Commission. 2003. SECPOP2000: Sector Population, Land 

Fraction, and Economic Estimation Program. Washington, DC: NRC. NUREG/CR-6525, 

Rev. 1. August 2003. ADAMS No. ML032310279. 

[NRC] U.S. Nuclear Regulatory Commission. 2004. Regulatory Analysis Guidelines of the U.S. 

Nuclear Regulatory Commission. Washington, DC: NRC. NUREG/BR-0058, Rev. 4. ADAMS 

No. ML003738939.

[NRC] U.S. Nuclear Regulatory Commission. 2005. EPRI/NRC-RES Fire PRA Methodology for 

Nuclear Power Facilities. Washington, DC: NRC NUREG/CR-6850. September 2005.

[NRC] U.S. Nuclear Regulatory Commission. 2007a. Letter from Mohan C. Thadani, U.S. 

NRC, to James J. Sheppard, STPNOC. Subject: “South Texas Project Units 1 and 2, Issuance 

of Amendments Re: Broad-scope Risk-informed Technical Specifications Amendments (TAC 

Nos. MD2341 and MD2342). Washington, D.C. July 13, 2007. ADAMS No. ML071780186.

[NRC] U.S. Nuclear Regulatory Commission. 2007b. An Approach for Determining the 

Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities. 

Regulatory Guide 1.200, Revision 1. Washington, D.C. January 2007. ADAMS 

No. ML063170035. 
Appendix F

F-36

[NRC] U.S. Nuclear Regulatory Commission. 2010. NRC Information Notice 2010-18: Generic 

Issue 199, Implications of Updated Probabilistic Seismic Hazard Estimates in Central and 

Eastern United States on Existing Plants. Washington, D.C. September 2, 2010. ADAMS 

No. ML101970221. 

[NRC] U.S. Nuclear Regulatory Commission. 2011a. Letter from Tam Tran, Project Manager, 

to G.T. Powell, STPNOC. Subject: Requests for Additional Information for the Review of the 

South Texas Project, License Renewal Application. Washington, D.C. May 31, 2011. ADAMS 

No. ML11140A015.

[NRC] U.S. Nuclear Regulatory Commission. 2011b. Letter from Tam Tran, Project Manager, 

to G.T. Powell, STPNOC. Subject: Requests for Additional Information for the Review of the 

South Texas Project, License Renewal Application. September 1, 2011. ADAMS 

No. ML112360114.

[NRC] U.S. Nuclear Regulatory Commission. 2011c. Memorandum from Tam Tran, Project 

Manager. Subject: Summary of Telephone Conference Call Held on July 28, 2011 between the 

U.S. Nuclear Regulatory Commission and STP Nuclear Operating Company, Concerning 

Requests for Additional Information Pertaining to the South Texas Project, License Renewal 

Application. August 23, 2011. ADAMS No. ML11216A263.

[NRC] U.S. Nuclear Regulatory Commission. 2012. Memorandum from Tam Tran, Project 

Manager. Subject: Summary of Telephone Conference Call Held on January 31, 2012 

between the U.S. Nuclear Regulatory Commission and STP Nuclear Operating Company, 

Concerning Requests for Additional Information Pertaining to the South Texas Project, License 

Renewal Application. February 14, 2012. ADAMS No. ML12033A134.

[STPNOC] South Texas Project Nuclear Operating Company. 2006. Letter from David W. 

Rencurrel, STPNOC to USNRC Document Control Desk, Subject: South Texas Project Units 1 

and 2, Docket Nos. STN 50-498, STN 50-499 Revised Broad Scope Risk-Informed Technical 

Specification Amendment Request.” Wadsworth, Texas. June 6, 2006. ADAMS 

No. ML061630315.

[STPNOC] South Texas Project Nuclear Operating Company. 2007. Letter from Charles T. 

Bowman, STPNOC, to U.S. Nuclear Regulatory Commission Document Control Desk, Subject: 

South Texas Project Units 1 and 2, Docket Nos. STN 50-498, STN 50-499, Response to NRC 

Requests for Additional Information on STPNOC Proposed Risk Managed Technical 

Specifications (TAC Nos. MD 2341 and MD 2342). Wadsworth, Texas. February 28, 2007. 

ADAMS No. ML070670369.

[STPNOC] South Texas Project Nuclear Operating Company. 2009. “South Texas Project 

Units 3 and 4 Combined License Application (COLA) (Environmental Report), Rev. 3.” 

September 2009. ADAMS No. ML092931600.

[STPNOC] South Texas Project Nuclear Operating Company. 2010. “South Texas Project—

License Renewal Application, Applicant’s Environmental Report, Operating License Renewal 

Stage, South Texas Project, Units 1 and 2.” September 2010. ADAMS No. ML103010263.

[STPNOC] South Texas Project Nuclear Operating Company. 2011a. Letter from G.T. Powell, 

STPNOC, to U.S. Nuclear Regulatory Commission Document Control Desk, Subject: South 

Texas Project Units 1 and 2, Docket Nos. STN 50-498, STN 50-499, Response to Request for 

Additional Information on South Texas Project License Renewal Application (TAC No. ME4938). 

July 5, 2011. ADAMS No. ML11193A016.
Appendix F

F-37

[STPNOC] South Texas Project Nuclear Operating Company. 2011b. “Additional Information 

on South Texas Project License Renewal Application (TAC No. ME4938).” August 23, 2011. 

ADAMS No. ML11250A067.

[STPNOC] South Texas Project Nuclear Operating Company. 2012a. Letter from D.W. 

Rencurrel, STPNOC, to U.S. Nuclear Regulatory Commission Document Control Desk, Subject: 

South Texas Project Units 1 and 2, Docket Nos. STN 50-498, STN 50-499, Supplemental 

Response to Request for Additional Information on South Texas Project License Renewal 

Application—SAMA (TAC Nos. ME4938 and ME5122). January 19, 2012. ADAMS 

No. ML12030A081.

[STPNOC] South Texas Project Nuclear Operating Company. 2012b. Letter from D.W. 

Rencurrel, STPNOC, to U.S. Nuclear Regulatory Commission Document Control Desk, Subject: 

South Texas Project Units 1 and 2, Docket Nos. STN 50-498, STN 50-499, Clarification to 

Supplemental Response to Request for Additional Information on South Texas Project License 

Renewal Application—SAMA (TAC Nos. ME4938 and ME5122). February 16, 2012. ADAMS 

No. ML12053A259.

[TVA] Tennessee Valley Authority. 2010. Letter from Masoud Bajestani, TVA, to U.S. Nuclear 

Regulatory Commission Document Control Desk. Subject: Watts Bar Nuclear Plant (WBN) 

Unit 2—Request for Additional Information Regarding Severe Accident Management 

Alternatives (TAC No. MD8203). July 23, 2010. ADAMS No. ML102100588.

Texas State Data Center, 2006. Available at: <http://txsdc.utsa.edu/> (Accessed May 2012). 

[USGS] U.S. Geological Survey. 2008. 2008 NSHM Gridded Data. Available at: 

<http://earthquake.usgs.gov/hazards/products/conterminous/2008/data/#fileformat> (Accessed 

May 2012).




UNITED STATES 

NUCLEAR REGULATORY COMMISSION

WASHINGTON, DC 20555-0001

--------------------

OFFICIAL BUSINESS
NUREG-1437

Supplement 48

Final

Generic Environmental Impact Statement for License Renewal of Nuclear Plants 

Regarding South Texas Project, Units 1 and 2

November 2013