Supplement to the

U.S. Department of Energy’s 

Environmental Impact

Statement for a Geologic

Repository for the Disposal

of Spent Nuclear Fuel and

High-Level Radioactive

Waste at Yucca Mountain,

Nye County, Nevada

Final Report

 

Office of Nuclear Material Safety and Safeguards

NUREG-2184

Supplement to the

U.S. Department of Energy’s 

Environmental Impact

Statement for a Geologic

Repository for the Disposal

of Spent Nuclear Fuel and

High-Level Radioactive

Waste at Yucca Mountain,

Nye County, Nevada

Final Report

Manuscript Completed: May 2016

Date Published: May 2016

Office of Nuclear Material Safety and Safeguards

NUREG-2184

 

iii 

ABSTRACT 

This “Supplement to the Department of Energy’s Environmental Impact Statement for a 

Geologic Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste 

at Yucca Mountain, Nye County, Nevada” (supplement) evaluates the potential environmental 

impacts on groundwater and impacts associated with the discharge of any contaminated 

groundwater to the ground surface due to potential releases from a geologic repository for spent 

nuclear fuel and high-level radioactive waste at Yucca Mountain, Nye County, Nevada. This 

supplements the U.S. Department of Energy’s (DOE’s) 2002 “Final Environmental Impact 

Statement for a Geologic Repository for the Disposal of Spent Nuclear Fuel and High-Level 

Radioactive Waste at Yucca Mountain, Nye County, Nevada” and 2008 “Final Supplemental 

Environmental Impact Statement for a Geologic Repository for the Disposal of Spent Nuclear 

Fuel and High-Level Radioactive Waste at Yucca Mountain, Nye County, Nevada,” in 

accordance with the findings and scope outlined in the U.S. Nuclear Regulatory Commission 

(NRC) staff’s 2008 “Adoption Determination Report for the U.S. Department of Energy’s 

Environmental Impact Statements for the Proposed Geologic Repository at Yucca Mountain.” 

This supplement describes the affected environment and assesses the potential environmental 

impacts with respect to potential contaminant releases from the repository that could be 

transported through the volcanic-alluvial aquifer in Fortymile Wash and the Amargosa Desert, 

and to the Furnace Creek/Middle Basin area of Death Valley. This supplement evaluates the 

potential radiological and nonradiological impacts—over a one million year period—on the 

aquifer environment, soils, ecology, and public health, as well as the potential for 

disproportionate impacts on minority or low-income populations. In addition, this supplement 

assesses the potential for cumulative impacts associated with other past, present, or reasonably 

foreseeable future actions. The NRC staff finds that each of the potential direct, indirect, and 

cumulative impacts on the resources evaluated in this supplement would be SMALL. 

v 

TABLE OF CONTENTS 

Section Page 

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

LIST OF FIGURES ........................................................................................................ vii 

LIST OF TABLES .......................................................................................................... ix 

EXECUTIVE SUMMARY ............................................................................................... xi 

ACRONYMS AND ABBREVIATIONS ......................................................................... xiii 

1 INTRODUCTION ............................................................................................... 1-1

1.1 Background—License Application and EIS Adoption Review Process .............. 1-1

1.2 Scope and Assumptions ..................................................................................... 1-2

1.2.1 Need for Supplementation and Scope of the Analysis ........................... 1-2

1.2.2 Analysis Assumptions ............................................................................. 1-3

1.2.3 Significance of Environmental Impacts ................................................... 1-4

1.3 Public and Agency Involvement ......................................................................... 1-5

1.4 Document Purpose and Structure ...................................................................... 1-5

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

2.1 Introduction ......................................................................................................... 2-1

2.1.1 Regional Demography ............................................................................ 2-4

2.2 Groundwater Environment ................................................................................. 2-5

2.2.1 Aquifers in the Death Valley Region ....................................................... 2-5

2.2.2 Aquifers Along the Flow Path From Yucca Mountain ............................. 2-7

2.2.3 Effects of Groundwater Pumping on Flow ............................................ 2-15

2.2.4 Past and Future Climates ..................................................................... 2-17

2.3 Surface Discharge Environments ..................................................................... 2-19

2.3.1 Ecology at Surface Discharge Sites ..................................................... 2-20

2.3.2 Cultural Resources at Surface Discharge Sites .................................... 2-21

2.3.3 Present-Day Discharge Sites ................................................................ 2-22

2.3.4 Paleodischarge Sites ............................................................................ 2-26

2.3.5 Summary of Surface Discharge Environments ..................................... 2-28

2.4 Groundwater Modeling ..................................................................................... 2-28

2.5 Water Use and Quality ..................................................................................... 2-31

2.6 Analysis Cases for Assessing Impacts ............................................................. 2-32

3 ENVIRONMENTAL IMPACTS .......................................................................... 3-1

3.1 Impacts on the Aquifer, Water and Soil .............................................................. 3-1

3.1.1 Analysis Case 1: Pumping at Amargosa Farms .................................... 3-6

3.1.2 Analysis Case 2: Surface Discharge Downstream of 

 Amargosa Farms .................................................................................. 3-14

3.1.2.1 State Line Deposits/Franklin Well Area ................................ 3-15

3.1.2.2 Furnace Creek and Middle Basin ......................................... 3-20

3.1.2.3 Alkali Flat .............................................................................. 3-30

3.2 Ecological Impacts ........................................................................................... 3-30

3.3 Historic and Cultural Resources ....................................................................... 3-33

3.3.1 Assessments in the DOE Environmental Impact Statements ............... 3-33

3.3.2 Assessment in the NRC Staff’s Adoption Determination 

 Report (2008)........................................................................................ 3-34
vi 

3.3.3 DOE’s Programmatic Agreement (2009) .............................................. 3-35

3.3.4 Additional DOE Analysis (2014) ........................................................... 3-35

3.3.5 NRC Staff Evaluation ............................................................................ 3-35

3.4 Environmental Justice ...................................................................................... 3-36

3.4.1 Assessments in DOE’s Environmental Impact Statements .................. 3-36

3.4.2 NRC Staff Assessment ......................................................................... 3-36

3.4.3 NRC Staff Conclusion ........................................................................... 3-40

3.5 Summary .......................................................................................................... 3-40

4 CUMULATIVE IMPACTS .................................................................................. 4-1

4.1 Methodology for Supplementing DOE’s Cumulative Groundwater 

Impacts Analysis ................................................................................................ 4-1

4.2 Spatial and Temporal Boundaries for Cumulative Groundwater Impacts ........... 4-2

4.3 Potentially Affected Resources........................................................................... 4-3

4.4 Other Past, Present, and Reasonably Foreseeable Future Actions ................... 4-3

4.4.1 Actions Identified in DOE’s EISs ............................................................. 4-3

4.4.2 NRC Staff Update and Supplementation of DOE EISs 

 Identification of Other Actions ................................................................. 4-6

4.5 Cumulative Impacts on Groundwater and from Surface Discharges .................. 4-8

4.5.1 Impact Assessment in DOE’s EISs ......................................................... 4-9

4.5.2 NRC Staff Supplementation of DOE EISs Cumulative 

 Impacts Assessment ............................................................................. 4-10

4.5.2.1 Cumulative Impacts on Affected Resources at 

 Amargosa Farms .................................................................. 4-11

4.5.2.2 Groundwater at Amargosa Farms ........................................ 4-11

4.5.2.3 Cumulative Impacts on Affected Resources at Natural 

 Surface Discharge Locations .............................................. 4-15

4.6 Conclusion ........................................................................................................ 4-20

5 SUMMARY OF ENVIRONMENTAL CONSEQUENCES .................................. 5-1

6 REFERENCES .................................................................................................. 6-1

7 GLOSSARY ...................................................................................................... 7-1

8 LIST OF PREPARERS ..................................................................................... 8-1

8.1 NRC Contributors ............................................................................................... 8-1

8.2 CNWRA Contributors ......................................................................................... 8-1

8.3 CNWRA Consultant ............................................................................................ 8-2

9 DISTRIBUTION LIST ........................................................................................ 9-1

10 INDEX ............................................................................................................. 10-1

APPENDIX A:  ANALYTICAL METHODS ................................................................. A–1

APPENDIX B:  RESPONSES TO PUBLIC COMMENTS ........................................... B–1
vii 

LIST OF FIGURES 

Figure Page 

2-1 Location of Selected Geographical Features Within the Death Valley 

Regional Groundwater Flow System. ........................................................................... 2-2 

2-2 Schematic Block Diagram Illustrating the Structural Relations Among 

Mountain Blocks, Valleys, and Groundwater Flow in the Region ................................... 2-6 

2-3 Death Valley Regional Groundwater Flow System (Outline in Green) With 

Further Delineations of Central Death Valley Subregion (Brown Line) Showing 

Basins (Black Dotted Lines), Numbered Sections (Numbered and Red Lines), and 

Flow Directions ............................................................................................................... 2-8 

2-4 Groundwater Flow Paths Inferred From Groundwater Geochemical Analyses ............ 2-10 

2-5 Groundwater Flow Paths for Contaminants for the Pumping (Yellow) and 

the No Pumping (Fuchsia) Analysis Cases. ................................................................. 2-13 

2-6 Location of Natural Groundwater Discharge Areas, Including Springs and 

Playas, in the Death Valley Regional Groundwater Flow System ................................ 2-24 

3-1 Dose History of Selected Radionuclides at Amargosa Farms for the Present 

Day (Top) and Cooler/Wetter (Bottom) Climates ......................................................... 3-13 

3-2 Dose History of Selected Radionuclides at State Line Deposits/Franklin 

Well Area for the Cooler/Wetter Climate ...................................................................... 3-20 

3-3 Dose History for Selected Radionuclides and Total Dose at the Furnace Creek 

Area for the Present-Day (Top) and the Cooler/Wetter (Bottom) Climate States ......... 3-27 

3-4 Dose History for Selected Radionuclides and Total Dose at Middle Basin for 

the Present-Day (Top) and Cooler/Wetter (Bottom) Climate States ............................ 3-29 

A–1 Mass Flux for Mo, Ni, and V Released From Repository (Top) and Reaching 

the Postclosure Compliance Location (Bottom) ............................................................ A–8 

A–2 Water Uses and Exposure Pathways in the Biosphere Conceptual Model ................. A–17 

ix 

LIST OF TABLES 

Table Page 

2-1 Annual Discharge Estimates for Natural Discharge Locations ..................................... 2-23 

2-2 Concentrations of Naturally-Occurring Constituents in Groundwater From 

Amargosa Farms and Furnace Creek Springs, for Potential Contaminants 

Contributing to Impacts Discussed in Chapter 3 .......................................................... 2-32 

3-1a Amount of Selected Radiological and Nonradiological Material From the 

Repository in the Aquifer Environment Between the Postclosure Compliance 

Location and Amargosa Farms. [1 kg = 2.2 lbs] ............................................................. 3-9 

3-1b Amount of Selected Radiological and Nonradiological Material From the 

Repository Accumulated at the Amargosa Farms Area [1 kg = 2.2 lbs] ......................... 3-9 

3-2 Peak Groundwater Concentrations of Radiological and Nonradiological 

Material From the Repository in the Aquifer at Amargosa Farms ................................ 3-10 

3-3 Peak Concentrations of Radionuclides and Chemical Materials 

in Soils at Amargosa Farms Area for Analysis Case 1 (Pumping) ............................... 3-12 

3-4 Peak Annual Dose Estimates for the Amargosa Farms Area ...................................... 3-15 

3-5 Impact of Nonradiological Contaminants at Amargosa Farms Using Estimates 

of Body Intake .............................................................................................................. 3-15 

3-6 Peak Soil Concentrations of Radiological and Nonradiological Contaminants 

at the State Line Deposits/Franklin Well Area in a Cooler/Wetter Climate State, 

Calculated Using the Evaporite and Salt Marsh Soil Models ....................................... 3-19 

3-7 Peak Annual Dose and Body Intake Estimates for the Cooler/Wetter Climate 

at the State Line Deposits/Franklin Well Area .............................................................. 3-19 

3-8 Amount of Radiological and Nonradiological Material (From the Repository) 

in the Aquifer Environment Between the Postclosure Compliance Location and 

Death Valley ................................................................................................................. 3-23 

3-9 Peak Concentrations of Radiological and Nonradiological Material From 

the Repository Discharging in Groundwater at Furnace Creek, Death Valley ............. 3-23 

3-10 Peak Soil/Evaporite Contaminant Concentrations for Middle Basin, Death Valley ...... 3-25 

3-11 Peak Annual Dose Estimates for the Furnace Creek Area .......................................... 3-27 

3-12 Peak Daily Intake for Mo at Furnace Creek ................................................................. 3-28 

3-13 Peak Annual Dose Estimates for Middle Basin ............................................................ 3-28 

3-14 Peak Daily Intake for Mo at Middle Basin .................................................................... 3-30 

3-15 Comparison of Estimated Groundwater and Soil Concentrations of 

Contaminants at Amargosa Farms With Ecological Impact Concentrations (ppm) ...... 3-32 

3-16 Comparison of Estimated Groundwater and Soil Concentrations 

of Contaminants at State Line/Franklin Well With Ecological 

Impact Concentrations (ppm) ....................................................................................... 3-32 

3-17 Comparison of Estimated Groundwater and Soil Concentrations of Contaminants 

at Death Valley Middle Basin With Ecological Impact Concentrations (ppm) .............. 3-32 

3-18 2010 Minority Populations and 2010-2014 5-Year Poverty Estimates for the 

Amargosa Valley Area ................................................................................................. 3-38 

3-19 2010 Minority Populations and 2010-2014 5-Year Poverty Estimates for the 

Death Valley Area ........................................................................................................ 3-38

B-1 Draft Supplement Public Comment Meeting Summaries and Transcripts .................... B–2

B-2 Comment Categories .................................................................................................... B–3 

B-3 Individuals Who Submitted Written or Oral Comment ............................................... B–113

xi 

EXECUTIVE SUMMARY 

This supplement evaluates the potential environmental impacts on groundwater and impacts 

associated with the discharge of any contaminated groundwater to the ground surface due to 

potential releases from a geologic repository for spent nuclear fuel and high-level radioactive 

waste at Yucca Mountain, Nye County, Nevada. This supplements the U.S. Department of 

Energy’s (DOE’s) 2002 “Final Environmental Impact Statement for a Geologic Repository for the 

Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain, Nye 

County, Nevada” and 2008 “Final Supplemental Environmental Impact Statement for a Geologic 

Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at 

Yucca Mountain, Nye County, Nevada,” in accordance with the findings and scope outlined in 

the U.S. Nuclear Regulatory Commission (NRC) staff’s 2008 “Adoption Determination Report for 

the U.S. Department of Energy’s Environmental Impact Statements for the Proposed Geologic 

Repository at Yucca Mountain.” 

In Section 3.2.1.4.2 of the Adoption Determination Report (ADR), the NRC staff found that 

DOE’s environmental impact statements (EISs) did not adequately characterize impacts from 

potential contaminant releases to groundwater and from surface discharges of groundwater. 

Specifically, DOE’s analysis does not provide adequate discussion of the cumulative amounts of 

radiological and nonradiological contaminants that may enter the groundwater over time and 

how these contaminants would behave in the aquifer and surrounding environments. This 

supplement provides the information the NRC staff identified as necessary in its ADR. Two 

distinct but related aspects of potential impacts on the groundwater system are addressed in 

this supplement. These are (i) the nature and extent of the repository’s impacts on groundwater 

in the aquifer (beyond the postclosure compliance location) and (ii) the potential impacts of the 

discharge of potentially contaminated groundwater to the ground surface. 

This supplement describes the affected environment with respect to the groundwater flow path 

for potential contaminant releases from the repository that could be transported beyond the 

postclosure compliance location through the volcanic-alluvial aquifer in Fortymile Wash and the 

Amargosa Desert, and to the Furnace Creek/Middle Basin area of Death Valley. The analysis in 

this supplement considers both radiological and nonradiological contaminants. Using 

groundwater modeling, the NRC staff finds that contaminants from the repository would be 

captured by groundwater withdrawal along the flow path, such as the current pumping in the 

Amargosa Farms area, or would continue to Death Valley in the absence of such pumping. 

Thus, this supplement provides a description of the flow path from the postclosure compliance 

location to Death Valley, the locations of current groundwater withdrawal, and locations of 

potential natural discharge along the groundwater flow path. The supplement evaluates the 

potential groundwater-related environmental impacts at these locations over a one-million year 

period following repository closure. 

To evaluate the environmental impacts, this supplement assumes the repository and 

performance characteristics in the DOE license application, as evaluated in the NRC staff’s 

Safety Evaluation Report. This supplement describes the potential impacts that could occur 

under different climate conditions and under different assumptions for groundwater withdrawal. 

The analysis in this supplement encompasses the range of credible future climates and human 

activities affecting groundwater in the Yucca Mountain region, and includes conservative 

assumptions for future conditions and processes. Future climates are projected to include 

periods that are relatively hot and dry (similar to present-day conditions) and periods that are 

relatively cooler and wetter over the one-million-year time period. These climate states are 

based on geologic evidence of past climate change cycles in the region. They are also 
xii 

consistent with DOE’s model of repository performance, in that they capture the rates of 

contaminant release and transport through the groundwater system. Projected human-induced 

climate change (a future climate that is warmer and drier than present, or the longer persistence 

of the present-day climate conditions) is represented within the range of potential climate 

conditions, repository performance, and water use considered in this supplement. 

This supplement evaluates the potential impacts on the aquifer environment, soils, ecology, and 

public health, as well as the potential for disproportionate impacts on minority or low-income 

populations. In addition, this supplement assesses the potential for cumulative impacts that 

may be associated with other past, present, or reasonably foreseeable future actions. 

Cumulative impacts on groundwater and from surface discharges of groundwater are the 

potential impacts of the proposed repository when added to the aggregate effects of other past, 

present, and reasonably foreseeable future actions. 

During the 91-day public comment period on the draft supplement, the NRC staff conducted five 

public meetings. The first public meeting, in Rockville, Maryland, featured a live webcast and 

moderated teleconference line to accommodate remote participants. Public meetings were also 

held in Las Vegas, Nevada, and Amargosa Valley, Nevada. The final two meetings were 

teleconference-only to ensure that stakeholders unable to participate in the previous public 

meetings were afforded another opportunity to present oral comments. Including comment 

letters and oral comments, the NRC received over 1,200 comments on the draft supplement. 

The NRC staff’s responses to these comments are in Appendix B of the supplement. Several 

changes were made to the final supplement in response to comments received on the draft 

supplement, as discussed in detail in the comment responses in Appendix B. 

The NRC staff finds that all of the impacts on the resources evaluated in this supplement would 

be SMALL. The NRC staff’s analysis includes the impact of potential radiological and 

nonradiological releases from the repository on the aquifer environment and at surface 

discharge locations of groundwater beyond the postclosure compliance location. The peak 

estimated annual individual radiological dose over the one-million-year period at any of the 

evaluated locations is 1.3 mrem [0.013 mSv]. This maximum dose is associated with pumping 

and irrigation at the Amargosa Farms area, and the estimated radiological dose at other 

potential surface discharge locations is lower. The NRC staff concludes that the estimated 

radiological doses are SMALL because they are a small fraction of the background radiation 

dose of 300 mrem/yr [3.0 mSv/yr] (including radon), and much less than the NRC annual dose 

standards for a Yucca Mountain repository in 10 CFR Part 63 {15 mrem [0.15 mSv] for the first 

10,000 years, and 100 mrem [1 mSv] for one million years, after permanent closure}. Based on 

conservative assumptions about the potential for health effects from exposure to low doses of 

radiation, the NRC staff expects that the estimated radiation dose would contribute only a 

negligible increase in the risk of cancer or severe hereditary effects in the potentially exposed 

population. Impacts to other resources at all of the affected environments beyond the 

postclosure compliance location from radiological and nonradiological material from the 

repository would also be SMALL. The cumulative impact analysis concludes that, when 

considered in addition to the incremental impacts of the proposed action, the potential impacts 

of other past, present, or reasonably foreseeable future actions would also be SMALL. 
xiii 

ACRONYMS AND ABBREVIATIONS 

ACHP Advisory Council on Historic Preservation 

ADR Adoption Determination Report 

 

BLM Bureau of Land Management 

 

CCD Census County Division 

CEQ Council on Environmental Quality 

CERCLA Comprehensive Environmental Response, Compensation, 

and Liability Act

CFR Code of Federal Regulations 

 

DOE U.S. Department of Energy 

DOI U.S. Department of the Interior 

DVRFS Death Valley Regional Flow System 

 

EIS environmental impact statement 

EPA U.S. Environmental Protection Agency 

 

FEPs features, events, and processes 

FR Federal Register 

 

HLW high-level radioactive waste 

 

IAEA International Atomic Energy Agency 

I iodine 

ICRP International Commission on Radiological Protection 

LLRW low-level radioactive waste 

 

MCL mean concentration limit 

Mo molybdenum 

mrem millirem 

mSv milliSievert 

 

NDWR Nevada Division of Water Resources 

NEDP National External Diploma Program 

NEPA National Environmental Policy Act 

NHPA National Historic Preservation Act 

Ni nickel 

NNSA National Nuclear Security Administration 

NNSS Nevada National Security Site

Np neptunium 

NRC U.S. Nuclear Regulatory Commission 

NWPA Nuclear Waste Policy Act 

NWRPO Nuclear Waste Repository Project Office 

 

Pu plutonium 

 

RFFAs reasonably foreseeable future actions 

RMEI reasonably maximally exposed individual 
xiv 

ROD record of decision 

 

SAR Safety Analysis Report 

Se selenium 

SEIS supplemental environmental impact statement 

SER Safety Evaluation Report 

SEZ solar energy zone 

SHPO State Historic Preservation Office 

SNF spent nuclear fuel 

SNWA Southern Nevada Water Authority 

SNDWR State of Nevada Division of Water Resources 

SWEIS Site-Wide Environmental Impact Statement 

 

Tc technetium 

TDS total dissolved solids 

Th thorium 

TSPA Total System Performance Assessment 

 

U uranium 

 

USFWS U.S. Fish and Wildlife Service 

USGS U.S. Geological Survey 

 

V vanadium 

 
1-1 

1 INTRODUCTION 

This “Supplement to the Department of Energy’s Environmental Impact Statement for a 

Geologic Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste 

at Yucca Mountain, Nye County, Nevada” (supplement) evaluates the potential environmental 

impacts on groundwater and impacts associated with the discharge of any contaminated 

groundwater to the surface due to potential releases from a geologic repository for spent 

nuclear fuel (SNF) and high-level radioactive waste (HLW) at Yucca Mountain, Nye County, 

Nevada. This supplements the U.S. Department of Energy’s (DOE’s) 2002 “Final 

Environmental Impact Statement for a Geologic Repository for the Disposal of Spent Nuclear 

Fuel and High-Level Radioactive Waste at Yucca Mountain, Nye County, Nevada” (DOE, 2002)

and 2008 “Final Supplemental Environmental Impact Statement for a Geologic Repository for 

the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain, 

Nye County, Nevada” (DOE, 2008a), in accordance with the findings and scope outlined in the 

U.S. Nuclear Regulatory Commission (NRC) staff’s 2008 “Adoption Determination Report for the 

U.S. Department of Energy’s Environmental Impact Statements for the Proposed Geologic 

Repository at Yucca Mountain” (NRC, 2008a). 

The NRC staff has prepared this supplement pursuant to the National Environmental Policy Act 

of 1969, as amended (NEPA) and the Nuclear Waste Policy Act of 1982, as amended (NWPA), 

as implemented in NRC’s regulations in Title 10 of the Code of Federal Regulations (CFR) 

Part 51. 

1.1 Background—License Application and EIS Adoption Review Process 

The NWPA specifies that in the United States, SNF and HLW will be disposed of in a deep 

geologic repository. Amendments to the NWPA in 1987 identified Yucca Mountain, Nevada, as 

the single candidate site for characterization as a potential geologic repository. DOE prepared a 

final environmental impact statement (EIS) related to the construction, operation, and closure of 

a potential geologic repository for HLW at Yucca Mountain, Nevada, in February 2002. The 

EIS accompanied the Secretary of Energy’s site recommendation to the President on 

February 14, 2002, pursuant to NWPA Section 114(f). In July 2002, Congress passed and the 

President signed a joint resolution designating Yucca Mountain as the site for development of a 

geologic repository. In October 2006, DOE announced its intent to prepare a supplemental EIS 

to update the 2002 EIS (71 FR 60490). 

DOE published a final supplemental EIS (SEIS) in June 2008. Also that June, DOE submitted 

its license application (DOE, 2008b), including the 2002 EIS and 2008 SEIS to NRC seeking 

authorization to construct a geologic repository at Yucca Mountain. In accordance with NWPA 

Section 114(f)(5) and NRC’s regulations in 10 CFR 51.109, NRC is to adopt DOE’s EIS to “the 

extent practicable.” The NRC staff reviewed DOE’s EISs and found, as stated in its Adoption 

Determination Report (ADR), that it is practicable for NRC to adopt the EISs, with further 

supplementation (NRC, 2008a). Specifically, the NRC staff determined that a supplement was 

needed because the NRC staff concluded that DOE’s EISs did not adequately address potential 

repository-related impacts on groundwater and from surface discharges of groundwater. 

After docketing the DOE license application and issuing the ADR in September 2008, the NRC 

staff began its licensing review and development of its Safety Evaluation Report (SER). In 

October 2008, the Commission issued a Notice of Hearing and Opportunity to Petition to 

Intervene, which began the adjudicatory process (NRC, 2008b). 
1-2 

In February 2010, the Secretary of Energy stated that the “Administration has determined that 

developing a repository at Yucca Mountain, Nevada is not a workable option.” (DOE, 2010) 

DOE filed a motion with the Atomic Safety and Licensing Board presiding over the adjudication 

seeking permission to withdraw its license application. The Board denied that request in 

June 2010, and the Commission did not overturn the Board’s decision. After Congress reduced 

funding for the NRC’s review of the license application, NRC began an orderly closure of its 

Yucca Mountain activities. On September 30, 2011, the Board suspended the adjudicatory 

proceeding, and the NRC staff’s Yucca Mountain license application review activities ceased. 

In August 2013, the U.S. Court of Appeals for the District of Columbia Circuit issued a decision 

directing the NRC to resume the licensing process for DOE’s license application. In 

November 2013, the Commission directed the NRC staff to complete the SER and requested 

that DOE prepare the EIS supplement that the NRC staff had determined to be necessary in the 

ADR. DOE informed the NRC that it would update a 2009 technical analysis it provided to NRC 

(DOE, 2014a; 2009a), but that it would not prepare a supplement to its EISs (DOE, 2014b). 

In January 2015, the NRC staff completed the five-volume SER (NRC, 2015a,b; 2014b; 

2010a). In February 2015, the Commission directed the NRC staff to prepare the EIS 

supplement. The adjudicatory proceeding remains suspended. 

1.2 Scope and Assumptions 

The NRC staff’s general approach in this supplement for evaluating the potential impacts to 

groundwater and from the surface discharge of groundwater is identified in the NRC staff’s 2008 

ADR and follows the guidance in NUREG–1748, “Environmental Review Guidance for Licensing 

Actions Associated with the Office of Nuclear Material Safety and Safeguards Programs: 

Final Report” (NRC, 2003). 

1.2.1 Need for Supplementation and Scope of the Analysis 

Section 3.2.1.4 of the ADR describes the NRC staff’s evaluation of the adequacy of the 

analyses in DOE’s 2002 and 2008 EISs. Since the ADR was prepared (in 2008), the NRC staff 

has not identified new information that would change the NRC staff’s position regarding the 

scope of this supplement, which is described in detail in the ADR. However, information may be 

identified that requires further supplementation of DOE’s 2002 and 2008 EISs in the future. 

Section 3.2.1.4.2 of the ADR, “Impacts on Groundwater and from Surface Discharge of 

Groundwater,” provides the NRC’s staff’s assessment of the groundwater and surface discharge 

impact analyses in DOE’s EISs. As described in the ADR, the NRC staff finds that the EISs did 

not adequately characterize potential contaminant release to groundwater and from surface 

discharges of groundwater. While DOE’s analysis of the postclosure behavior of the repository 

recognizes that the release of contaminants to groundwater can be expected over the long term, 

the analysis does not provide adequate discussion of the cumulative amounts of radiological 

and nonradiological contaminants that may enter the groundwater over time, and how these 

contaminants would behave in the aquifer and surrounding environments. 

This supplement provides the information the NRC staff identified as necessary in its ADR. Two 

distinct but related aspects of potential impacts on the groundwater system are addressed in 

this supplement. These are (i) the nature and extent of the repository’s impacts on groundwater 

in the aquifer and (ii) the potential impacts of the discharge of potentially contaminated 

groundwater to the ground surface. These two aspects are described further below: 
1-3 

Impacts on Groundwater

 A description of the full extent of the volcanic-alluvial aquifer, particularly those parts that 

could become contaminated, and how water (and potential contaminants) can leave the 

flow system. 

 An analysis of the cumulative amount of radiological and nonradiological contaminants 

that can be reasonably expected to enter the aquifer from the repository, and the amount 

that could reasonably remain over time. 

 Estimates of contamination in the groundwater, given potential accumulation of 

radiological and nonradiological contaminants. 

Impacts from Surface Discharges of Groundwater 

 A description of the locations of potential natural discharge of contaminated groundwater 

for present and expected future wetter periods. 

 A description of the physical processes at potential surface discharge locations that 

could affect accumulation, concentration, and potential remobilization of contaminants 

carried by groundwater. 

 Estimates of the amount of contaminants that could be deposited at or near the surface, 

including estimates of the amount of discharged groundwater and near-surface 

evaporation; the amounts of radiological and nonradiological contaminants in that 

groundwater; contaminant concentrations in resulting deposits; and potential 

environmental impacts. 

This supplement assesses the potential groundwater and surface discharge impacts over a 

period of approximately one million years after repository closure. 

1.2.2 Analysis Assumptions 

The analyses in this supplement make the following assumptions: 

 Repository characteristics and performance are consistent with the information DOE 

provided in its license application, as well as the conclusions in the NRC staff’s SER. 

The NRC staff found (i) the analytic models in DOE’s performance assessment for the 

repository to be technically sound and to provide an acceptable representation of 

repository performance, including the representation of unlikely features, events, and 

processes (FEPs); and (ii) DOE’s technical basis for excluding certain FEPs from the 

performance assessment was acceptable (NRC, 2014a; Section 2.2.1.4.1). Information 

from DOE’s application, supporting documents, and the NRC staff’s SER, is referenced 

in this supplement where appropriate. 

 The current population in the area near Yucca Mountain and its distribution 

(as discussed in NRC, 2015a; Section 2.1.1.1.3.2, Regional Demography) will continue 

for the period analyzed in the supplement (approximately one million years). The 

supplement assumes the current range of human activities will also continue for this 

period. This is consistent with 10 CFR Part 63, Subpart L. 
1-4 

 With the exception of assumptions concerning groundwater pumping (described below), 

the NRC staff did not speculate about the types of future human activities that could 

occur far in the future. Unsupportable assumptions about human activities far in the 

future would result in correspondingly unsupportable conclusions about the potential 

impacts. This is consistent with NRC regulations in 10 CFR 63.305(b) and the 

U.S. Environmental Protection Agency regulations in 40 CFR 197.15, which direct the 

DOE not to project changes in society, the biosphere (other than climate), human 

biology, or increases or decreases of human knowledge or technology. 

This supplement describes the potential impacts that could occur under different climate 

conditions and different groundwater-use rates. These conditions are described as analysis 

cases that provide a representative range of credible future climates and human activities 

affecting groundwater in the Yucca Mountain area. These cases are discussed in more detail in 

Section 2.3. Based on data from past climates in the Yucca Mountain region, future climates 

are projected to include interglacial periods that are relatively hot and dry (similar to present 

conditions) and periods that are relatively cooler and wetter. The present-day climate is an 

interglacial period. The analysis in this supplement makes no assumptions about the timing of 

these potential future climate states, only that such conditions can be expected to occur 

sometime during the approximately one-million-year period evaluated in this supplement. 

In addition, the supplement considers two scenarios concerning potential groundwater 

withdrawal to encompass uncertainty in predicting future human activity that may affect the 

groundwater. These scenarios, considered in the analysis cases in Chapter 2 of this document, 

include the scenario where significant pumping for irrigation purposes (i.e., substantial removal 

of groundwater) will occur, as well as the scenario where limited or no pumping (i.e., no 

substantial removal of groundwater) will occur. Both of these pumping scenarios are 

considered for both the dry and wet climate states described above to create the analysis cases 

evaluated in this supplement. The NRC staff is addressing different pumping cases and 

different climate states because the amount of groundwater pumping affects where groundwater 

ultimately reaches the surface, while a wetter climate affects the amount of groundwater flow, 

and thus the concentrations of contaminants in the groundwater. As discussed in Chapter 2 of 

this document, changes in climate are not expected to significantly affect the groundwater flow 

paths in the area. 

Presently available information about human-induced climate change from the release of 

greenhouse gases indicates that for this region, the most potentially significant long-term effect 

is that the present-day interglacial climate (hot and dry) would persist longer than it would in 

the absence of human-induced change (NRC, 2014a; Section 2.2.1.3.5). Projected 

human-induced climate change is represented within the range of potential climate conditions 

(i.e., both dry and wet climate states) and water use (i.e., both substantial and no substantial 

removal of groundwater from the system) considered in this supplement. 

1.2.3 Significance of Environmental Impacts 

The NRC has established standards of significance for assessing environmental impacts. In 

NRC environmental reviews, significance indicates the importance of potential environmental 

impacts and is determined by considering two variables: (i) context and (ii) intensity. Context is 

the geographic, biophysical, and social setting in which effects are expected to occur. Intensity 

refers to the severity of the impact. The NRC uses a three-level standard of significance based 

upon the President’s Council on Environmental Quality guidelines in 40 CFR 1508.27 and as 

provided in the NRC’s environmental review guidance in NUREG–1748 (NRC, 2003): 
1-5 

SMALL: The environmental effects are not detectable or are so minor that they will 

neither destabilize nor noticeably alter any important attribute of the resource. 

MODERATE: The environmental effects are sufficient to alter noticeably, but not to 

destabilize, important attributes of the resource. 

LARGE: The environmental effects are clearly noticeable and are sufficient to 

destabilize important attributes of the resource. 

1.3 Public and Agency Involvement 

The NRC staff announced its intent to develop this supplement in the Federal Register (FR) on 

March 12, 2015 (80 FR 13029). The NRC staff also issued a press release, and notified the 

hearing participants and other stakeholders. 

Pursuant to 10 CFR 51.26(d), the NRC staff did not conduct scoping for this supplement, the 

scope of which was established by the ADR. The NRC staff did not identify any cooperating 

agencies for this supplement, nor did the NRC staff receive any formal requests for cooperating 

agency status. 

The NRC staff provided a 60-day public comment period for this draft supplement that was later 

extended to 91 days. The comment period began on August 21, 2015 (80 FR 50875) and 

closed on November 20, 2015 (80 FR 56501). During the comment period, the NRC staff 

conducted five public meetings. The first public meeting, in Rockville, Maryland, featured a live 

webcast and moderated teleconference line to accommodate remote participants. Public 

meetings were also held in Las Vegas, Nevada, and Amargosa Valley, Nevada. The final two 

meetings were teleconference-only to ensure that stakeholders unable to participate in the 

previous public meetings were afforded another opportunity to present comments. The NRC 

received over 1,200 oral and written comments on the draft supplement. The NRC staff’s 

responses to these comments are in Appendix B. 

1.4 Document Purpose and Structure 

This supplement does not reflect a change to DOE’s proposed action or to DOE’s purpose and 

need for the proposed action. DOE’s purpose and need for the proposed action, as described 

in Chapter 1 of DOE’s 2002 EIS and 2008 SEIS, is that for many years civilian and 

defense-related activities have produced SNF and HLW, and these materials have 

accumulated—and continue to accumulate—at commercial and DOE sites across the 

United States. In passing the NWPA in 1982, Congress affirmed that the Federal Government 

is responsible for the permanent disposal of SNF and HLW. As discussed in Section 1.1, in the 

1987 amendments to the Act, the Yucca Mountain site was designated for further consideration 

as a repository for the permanent disposal of these materials. (DOE, 2002) 

DOE’s proposed action, as described in Chapter 2 of the 2002 EIS and 2008 SEIS, is the 

construction, operation, monitoring, and closure of a repository for the disposal of SNF and 

HLW at Yucca Mountain, Nevada. The NRC’s proposed action would be the issuance of an 

authorization to DOE for the construction of a repository at Yucca Mountain, as described in 

DOE’s license application. This supplement also does not reflect a change in the alternatives 

DOE presented in Chapter 2 of its EISs, which are the proposed action and the no action 

alternative of not constructing a repository. As discussed in the ADR, these aspects of DOE’s 

NEPA analysis are not affected by this supplement, and they are not addressed further. 
1-6 

This supplement presents additional information about the impacts of potential repository 

contamination of groundwater, as well as the potential impacts associated with the discharge of 

contaminated groundwater to the surface. As such, the supplement affects the information 

presented in DOE’s analyses of affected environment, impacts after repository closure, and 

cumulative impacts in its EISs. 

Chapter 2 of this supplement describes the potentially affected groundwater and surface 

environments and the potentially affected resource areas for each environment. Chapter 3 

describes the potential impacts of repository contamination of groundwater and from the surface 

discharge of groundwater. Chapter 4 describes cumulative impacts associated with potential 

repository contamination of groundwater and the surface discharge of that groundwater. 

Chapter 5 provides a summary of the NRC staff’s impact findings.
2-1 

2 AFFECTED ENVIRONMENT 

2.1 Introduction 

The U.S. Department of Energy’s (DOE’s) Environmental Impact Statement (EIS) (DOE, 2002, 

Chapter 5) and Supplemental Environmental Impact Statement (SEIS) (DOE, 2008a, Chapter 5) 

described the affected environment from the Yucca Mountain repository site to the location of 

the reasonably maximally exposed individual (RMEI), or postclosure compliance location,1

 in the 

Amargosa Desert using information from a model that DOE developed for its license application 

(DOE, 2008b). The RMEI location is characterized using features of present-day conditions and 

activities at Amargosa Farms (the south-central portion of Amargosa Desert, as shown in 

Figure 2-1). Amargosa Farms is the primary area of population and groundwater pumping in 

the town of Amargosa Valley. Using these conditions, the location of the RMEI is approximately 

18 km [11 mi] from Yucca Mountain, along the flow path of the predominant groundwater flow, 

and approximately at the southern boundary of the Nevada National Security Site (NNSS) 

(NRC, 2014a). For locations beyond the postclosure compliance location, the analysis in DOE’s 

2002 EIS and 2008 SEIS scaled the results calculated for the postclosure compliance location 

to generic locations at 30 km [19 mi] and 60 km [37 mi] from the repository in the predominant 

direction of groundwater flow.

The U.S. Nuclear Regulatory Commission (NRC) staff’s review of DOE’s EISs found that it was 

practicable for the NRC to adopt the 2002 EIS and 2008 SEIS, but with further supplementation 

(NRC, 2008a). The NRC staff concluded that a supplement was needed to describe the full 

spatial extent of the volcanic-alluvial aquifer beyond the postclosure compliance location, 

particularly those parts that could become contaminated by potential releases from the 

repository, and how water (and potential contaminants) could leave the flow system. 

Specifically, the NRC staff’s review of the EISs concluded that the affected groundwater 

environments, and any impacts, were not adequately identified and described by DOE’s 

analyses for areas beyond the postclosure compliance location. 

This chapter provides a description of the affected environment with respect to the groundwater 

flow path for potential releases from the repository that could be transported beyond the 

postclosure compliance location through the volcanic-alluvial aquifer in Fortymile Wash and 

Amargosa Desert. Groundwater flow and potential releases traveling beyond the postclosure 

compliance location, if uninterrupted, would discharge in Death Valley. Death Valley is the 

ultimate discharge area for groundwater flow in the Death Valley Regional Groundwater Flow 

System (DVRFS) (Figure 2-1). Importantly, discharge to the surface (e.g., springs) and the 

pumping of groundwater along the flow path towards Death Valley reduces the amounts of 

groundwater (and therefore, the amount of any contaminants) that discharge in Death Valley. 

This chapter provides a description of the flow path towards Death Valley, and the locations of 

potential natural discharge along the groundwater flow path for present and expected future 

cooler and wetter periods. It also evaluates current and potential future water use that might 

affect the groundwater flow paths and natural discharge for present and future wetter periods. 

 

1

The term “postclosure compliance location” is used throughout the supplement for the postclosure regulatory 

compliance location. This point is defined and specified at 10 CFR 63.312(a) as the point of compliance for 

calculating dose with respect to postclosure individual protection, human intrusion, and groundwater protection 

standards. This location is based on the definition of the controlled area in 10 CFR 63.302. The model DOE used to 

support its license application calculates radiological dose to a reasonably maximally exposed individual located at a 

point on the NNSS boundary that is approximately 18 km [11 mi] south of the analyzed repository footprint in the 

predominant direction of groundwater flow. 
2-2 

Figure 2-1. Location of Selected Geographical Features Within the Death Valley 

Regional Groundwater Flow System. NNSS Is the Nevada National Security 

Site (Previously Called the Nevada Test Site). Modified From Belcher and 

Sweetkind (2010). 
2-3 

The affected environment for contaminants released from the repository, therefore, includes the 

aquifer itself as well as the sites where groundwater could discharge to the surface, either 

through pumping or natural processes. 

In particular, this chapter describes: 

(i) Groundwater Environment (Section 2.2)

— Aquifers in the region potentially affected by releases from Yucca Mountain, 

including aquifers along the flow path from Yucca Mountain to Death Valley

 — Effects of groundwater pumping on groundwater flow

 — Effects of the present and possible future climates on groundwater flow

(ii) Surface Discharge Environment (Section 2.3)

— Present-day discharge sites for releases from Yucca Mountain along potential 

flow paths beyond the postclosure compliance location 

— Paleodischarge sites (areas of prehistorical, but not current surface discharge) 

during wetter and cooler climates as indicators of potential future discharge 

(iii) Groundwater Modeling (Section 2.4)

— Effects of pumping on groundwater conditions

— Effects of climate on future flow paths

(iv) Water Use and Quality (Section 2.5)

— Water use along potential flow paths

— Groundwater quality in the Yucca Mountain region 

(v) Analysis Cases for Assessing Impacts (Section 2.6)

— Present-day pumping levels (all potential contaminant releases are assumed to 

be captured by pumping wells at the postclosure compliance location)

— No future pumping (surface discharges downstream of the postclosure 

compliance location under present and possible future climates)

The descriptions of groundwater flow and surface discharges in this chapter are drawn from 

sources including the U.S. Geological Survey (USGS) (e.g., Belcher and Sweetkind, 2010), 

Nye County (Nye County NWRPO, 2009), and Inyo County (e.g., Bredehoeft and King, 2010; 

Bredehoeft et al., 2008; Inyo County, 2007), as well as independent NRC staff analyses 

(e.g., NRC, 2014a). The descriptions in this chapter also incorporate further work by DOE on 

the flow system beyond the postclosure compliance location (DOE, 2014a; 2009a). 
2-4 

2.1.1 Regional Demography 

As discussed in Chapter 1, the NRC staff assumes the current population and its distribution, as 

well as the current range of human activities, will continue for the entire period analyzed in the 

supplement. This is consistent with NRC regulations in title 10 of the Code of Federal 

Regulations (CFR) 63.305(b) and U.S. Environmental Protection Agency (EPA) regulations in 

40 CFR 197.15, which direct DOE not to project changes in society, the biosphere (other than 

climate), human biology, or increases or decreases in human knowledge or technology. 

Using data from the 2010 U.S. census, the NRC staff found in its Safety Evaluation Report 

(SER) (NRC, 2015a; Section 2.1.1.1.3.2) that DOE’s assessment of the demographic 

characteristics of the area surrounding 

Yucca Mountain was accurate. In its license 

application, DOE described population 

locations, regional population centers, 

and provided population projections for a 

50-year period (2017-2067) (DOE, 2008b; 

Section 1.1.2). DOE’s assessment 

encompassed an 84-km [52-mi] radial area, 

centered on the repository site. The area 

comprises parts of Clark, Esmeralda, Lincoln, 

and Nye Counties in Nevada, and Inyo 

County in California. DOE provided a 

baseline population distribution within the 

84-km [52-mi] radius for the 50-year period. 

DOE did not identify any permanent residents 

closer than about 22 km [13.7 mi] to the 

repository site. The nearest resident 

population was located in the town of 

Amargosa Valley, Nevada.

For its SER, the NRC staff performed independent confirmatory calculations for DOE’s baseline 

2003 population distribution within 84 km [52 mi] of the repository. The NRC staff’s results are 

consistent with DOE’s information. The NRC staff also compared the U.S. Census Bureau data 

for the 2010 population distribution within 84 km [52 mi] of the repository location with that of 

DOE’s projected population distribution data and found that DOE’s estimate is generally higher, 

and therefore conservative in terms of potential impacts. The NRC staff further found in the 

SER that DOE identified all significant population centers within an appropriate demographic 

study area {within 84 km [52 mi]} and used population data consistent with other acceptable 

evaluations of demography and population centers in the repository area (NRC, 2015a). 

The NRC staff incorporates by reference its SER assessment (NRC, 2015a; Section 2.1.1.1.3.2) 

and DOE’s license application description of regional demography (DOE, 2008b; Section 1.1.2) 

because the NRC staff has determined that groundwater could discharge to the surface in or 

near population centers. These population centers are the town of Amargosa Valley and 

Death Valley National Park (NRC, 2015a; Section 2.1.1.1.3.2., Population Centers). The 

population in Death Valley includes the Timbisha Shoshone Tribe community located on a 

314-acre [1.27-km2

] parcel of land in the Furnace Creek area. The Tribe has federally 

appropriated rights to 92 acre-feet per year [0.113 million m3

/yr] of surface and groundwater to 

support this community (DOE, 2014a; 16 U.S.C. 410aaa). 

Town of Amargosa Valley 

The unincorporated town of Amargosa Valley, 

previously called Lathrop Wells, contains an 

informally defined area called Amargosa Farms 

that is the primary populated and farming area 

of the town. The town borders the southwest 

corner of the Nevada National Security Site and 

the postclosure compliance location, and 

extends south and southwestward covering an 

area of 505 mi2 [1,308 km2], as shown in the 

Amargosa Valley Area Plan (2009). Much of 

the town of Amargosa Valley is not in the 

groundwater pathway from Yucca Mountain; 

however, the Amargosa Farms area is within 

the range of uncertainty for the pathway of 

groundwater from Yucca Mountain.
2-5 

2.2 Groundwater Environment 

2.2.1 Aquifers in the Death Valley Region 

The DVRFS lies within the southern portion of the arid, internally drained region known as the 

Great Basin. The principal groundwater-bearing units in the DVRFS can be classified as 

volcanic, alluvial, or carbonate aquifers (DOE, 2014a; 2008a), depending on the types of rock or 

sediment through which the groundwater flows. The mountainous areas in the north-central 

portion of the DVRFS are mostly of volcanic origin and contain associated volcanic aquifers 

(i.e., aquifers composed principally of fractured tuff and other volcanic rocks). In the lower 

elevations and in portions of the southern area, the volcanic aquifer in some areas connects 

with relatively young permeable basin fill sediments (mostly deposited by streams, also called 

alluvium or alluvial deposits) in valleys across the DVRFS. These sediments comprise the 

affected alluvial aquifer. The lowermost aquifer is a deep regional groundwater system formed 

of thick sequences of older, highly permeable carbonate rocks that foster interbasinal 

groundwater flow between basins that are topographically closed (Belcher and Sweetkind, 

2010), as illustrated schematically in Figure 2-2. Regional groundwater flow in the DVRFS 

through the carbonate rock sequence is affected by complex geologic structures caused by 

regional faulting and fracturing. These geological structures can enhance or impede flow 

(DOE, 2008b, Section 2.3.9). Although the carbonate aquifer is generally regionally connected 

and fast flowing (Sweetkind et al., 2010; Winograd and Thordarson, 1975), there is also some 

evidence from geochemical and temperature data that it may be locally compartmentalized 

(e.g., Bushman et al., 2010; Nye County NWRPO, 2009). The compartmentalized areas are a 

possible consequence of a complex geological structure in the DVRFS, where local faulting may 

intersperse less-permeable units. 

The basin fill sediments and fractured volcanic rocks form local aquifers, and in some areas 

they are well connected such that groundwater can flow easily from volcanic to alluvial sections. 

The volcanic and alluvial aquifers interact with the regional carbonate aquifer either through 

(i) vertical flow if the carbonate aquifer underlies the volcanic-alluvial aquifer, or (ii) lateral flow, 

where the carbonate aquifer, due to faulting, juxtaposes alluvial-volcanic aquifers (Belcher and 

Sweetkind, 2010). At any one location, confining layers between the aquifers at different depths 

allow varying degrees of water exchange between aquifers. 

The NRC staff’s description of the entire regional flow system derives from the integration of 

geologic data (rock units and structures), hydrologic data (potentiometric and hydrologic 

properties of the rock), water chemistry data, and temperature data for each aquifer in the flow 

system (e.g., Belcher and Sweetkind, 2010; DOE, 2014a). For example, water levels in wells 

across the DVRFS provide data regarding the hydraulic gradient, and thus, the potential 

directions of water flow. These include indications of the potential for vertical flow between 

aquifers and differing horizontal flow directions of shallow and deep aquifers. Also, water 

temperature can provide indications of deeper groundwater interacting with shallower aquifers, 

or of deeper water discharging to the ground surface. 

Groundwater chemical compositions are used to understand groundwater flow paths and 

identify areas in which groundwater mixing occurs. Groundwater chemistry is influenced by 

interactions with the rock through which it flows. Interactions may include dissolution of 

minerals, ion-exchange between the water and minerals, chemical alteration of mineral phases, 

and precipitation of new mineral phases. Through these interactions, the groundwater develops 

a chemical composition that is characteristic of a particular aquifer system. For example, 

groundwater in the volcanic tuff aquifer system typically has relatively low ionic strength and has 
2-6 

Figure 2-2. Schematic Block Diagram Illustrating the Structural Relations Among 

Mountain Blocks, Valleys, and Groundwater Flow in the Region 

(Modified From Eakin et al., 1976). Taken From Belcher and Sweetkind 

(2010; Figure D-1).

higher concentrations of sodium, potassium, and silica derived from the volcanic source rocks. 

In contrast, groundwater in the carbonate aquifer is dominated by dissolved calcium, 

magnesium, and bicarbonate. 

Groundwater Subregions, Basins, and Sections 

To simplify modeling of the entire DVRFS and support modeling at different scales, the USGS 

created a hierarchy of subregions, basins, and sections, from largest to smallest, respectively 

(most recently described in Belcher and Sweetkind, 2010). DOE used earlier versions of the 

USGS delineation of these groundwater flow areas (e.g., Belcher, 2004; Belcher et al., 2002) at 

different scales in its EIS (DOE, 2002) and SEIS (DOE, 2008a). This delineation is a 

reasonable method for conceptualizing the DVRFS, and this supplement utilizes the same 

terminology. The delineation is reasonable because it is based on (i) an understanding of the 

geology, including the rock units and structures that may influence groundwater flow; 

(ii) observations or estimates of hydrologic information, including potentiometric surface 

(for unconfined aquifers, the water table elevation is the potentiometric surface) and 

hydrological properties of hydrogeological units; (iii) hydrogeochemical and thermal information; 

and (iv) groundwater modeling that integrates all the hydrogeological information together. 

Modeling the groundwater system involves characterizing the inflows and outflows for each 

section, basin, and subregion. The inflows and outflows include recharge, lateral inflow and 

outflow between areas, pumping, discharge related to springs, and evapotranspiration 

(movement of water directly to air from ground surface and from plants).
2-7 

Amargosa River 

The Amargosa River is an intermittent waterway, 

298 km [185 mi] long, in southern Nevada and 

eastern California. It drains the Amargosa Valley 

in the Amargosa Desert and other smaller valleys 

on its way to Death Valley. Except for a small 

portion of its route near Beatty, Nevada, and a 

portion in the Amargosa Canyon (near the towns of 

Shoshone and Tecopa) in California, the river 

flows above ground only after rare major rainstorm 

events in the region (see also Menges, 2008).

Following the hierarchical delineation by the USGS, the DVRFS is divided at the largest scale 

level into three subregions (Belcher and Sweetkind, 2010). The proposed repository site at 

Yucca Mountain is in volcanic tuff and lies above part of the large volcanic aquifer in the 

Central Death Valley Subregion (Figures 2-1 and 2-3). As discussed in the subsequent 

sections, this Subregion contains the aquifers likely to be affected by contaminants released 

from the repository. Some small portion of groundwater flow from beneath Yucca Mountain may 

enter the Southern Death Valley Subregion to the south and east. The third subregion, to the 

west and north of the Central Death Valley Subregion, is the Northern Death Valley Subregion, 

and is not affected by flow from beneath Yucca Mountain. The subregions are further 

subdivided into basins, which themselves are subdivided into sections. Yucca Mountain falls in 

the Fortymile Canyon Section, which is part of the Alkali Flat-Furnace Creek Basin, which is part 

of the Central Death Valley Subregion, as shown in Figure 2-3. 

The other two basins delineated in the Central Death Valley Subregion (Pahute Mesa-Oasis 

Valley and Ash Meadows Basins) contribute lateral water flow into the Alkali Flat-Furnace Creek 

Basin at its northern, eastern, and western boundaries. 

The NRC staff next evaluates the principal groundwater flow path between Yucca Mountain and 

Death Valley, within the Alkali Flat-Furnace Creek Basin, and the potential minor flow into the 

Southern Death Valley Subregion. 

2.2.2 Aquifers Along the Flow Path From Yucca Mountain 

This section describes the expected flow path for groundwater from below the proposed 

repository. In the 2002 EIS and 2008 SEIS, DOE described the flow path from the repository to 

the area of pumping at the postclosure compliance location in the Amargosa Desert. DOE 

described the flow of water in the unsaturated zone through the repository and vertically 

downward to the underlying saturated volcanic rocks. This flow path is the same as that 

described in DOE’s Safety Analysis Report (SAR) for performance of the repository 

(DOE, 2008b, Section 2.3.9). DOE found that such water flow is the principal means of release 

of contaminants from repository once the engineered barriers cease to contain the waste 

(DOE, 2008a,b). The NRC staff found the description of this flow path to the postclosure 

compliance location to be acceptable in its Adoption Determination Report (ADR) (NRC, 2008a); 

the NRC staff’s review of repository performance is given in its SER (NRC, 2014a; 

Section 2.2.1.3.8). 

The flow system that passes below 

Yucca Mountain trends southward along 

Fortymile Wash in the Fortymile Canyon 

Section (Figure 2-3). Beyond the postclosure 

compliance location, it merges with 

east-southeast flow in the Amargosa Desert 

and continues south towards 

Amargosa Farms. The next sections of this 

chapter provide descriptions of the 

groundwater flow path in the 

Amargosa Farms area of the southcentral 

portion of the Amargosa River Section, and 

between the Amargosa Farms area and Death Valley, predominantly westward through the 

carbonate aquifer at the eastern Funeral Mountains (the Funeral Mountain Section of the flow 

path). In addition, the potential, minor flow from Amargosa Farms to Alkali Flat is also 
2-8 

Figure 2-3. Death Valley Regional Groundwater Flow System (Outline in Green) With 

Further Delineations of Central Death Valley Subregion (Brown Line) 

Showing Basins (Black Dotted Lines), Numbered Sections (Numbered and 

Red Lines), and Flow Directions. Taken From Belcher and Sweetkind 

(2010; Figure D–7). 

described. As discussed in the sections below, particle tracking analysis using the DVRFS 

model indicates the possible pathways for contaminants from a repository at Yucca Mountain 

past the Amargosa Farms area are westward through the Funeral Mountains to Death Valley, or 

along the Amargosa River course to discharge at Alkali Flat. 
2-9 

Fortymile Canyon Section 

The first portion of the flow path is in the Fortymile Canyon Section (Figure 2-3; labeled 3a). As 

described in the 2008 SEIS, infiltrating water at Yucca Mountain passes through the 

unsaturated zone, reaches the uppermost volcanic aquifer, and then flows east to southeast to 

join the larger volume of groundwater flowing southward along Fortymile Wash towards 

Amargosa Desert. The first part of this flow path is within the volcanic aquifer. Flow in these 

volcanic rocks occurs predominantly in networks of fracture and fault zones. Along Fortymile 

Wash, the strata (layers) of the volcanic aquifer thin and transition into the sediments of the 

alluvial aquifer. The groundwater then exits the fractured volcanic tuffs and enters the relatively 

unconsolidated granular porous media of the alluvial aquifer. This transition occurs in the 

vicinity of the Highway 95 fault (a poorly-expressed west-northwest striking high-angle fault 

zone that occurs just south of the southern boundary of NNSS, as shown in Figures 2-1 and 

2-3, near the label “Jackass Flats”). The Highway 95 fault appears to be the southern boundary 

of the volcanic aquifers, based on a fault zone geometry inferred from borehole and geophysical 

data (DOE, 2008a; Nye County NWRPO, 2009). The fault juxtaposes fractured volcanic rocks 

on the north side with less permeable alluvial sediments on the south side. Nye County 

investigators proposed that contact with the less permeable alluvial sediments causes the 

southward groundwater to flow up into an overlying alluvial aquifer system, which continues 

to the Amargosa Desert (Nye County NWRPO, 2009). Hydraulic measurements conducted 

by DOE and Nye County support a slight upward gradient in the alluvial aquifer (DOE, 2008a; 

p. 3–33), which, when combined with the stratified alluvial sediments, indicates that a 

groundwater plume emanating from Yucca Mountain would remain in the upper portion of the 

uppermost alluvial aquifer in the Amargosa Desert. The transition from the Fortymile Canyon 

Section to the Amargosa River Section coincides approximately with the postclosure 

compliance location {approximately 18 km [11 mi]} along the flow path from the proposed 

repository site. In this area, distributed recharge occurs in mountainous areas and focused 

recharge from intermittent streamflow occurs in smaller washes. Losses from the aquifer are 

predominantly by evapotranspiration. 

Amargosa River Section 

The next portion of the flow path is in the Amargosa River Section (Figure 2-3; labeled 3b). The 

groundwater flow path from Yucca Mountain goes southward from Fortymile Wash into the 

Amargosa Desert. Groundwater geochemical data indicate that the flow paths within the alluvial 

aquifer of Fortymile Wash are readily identifiable along the length of Fortymile Wash and 

southward across the Amargosa Desert (Figure 2-4) (Kilroy, 1991; SNL, 2007a). 

Amargosa Farms is a small farming community which occupies the area where the alluvial fan 

(a fan- or cone-shaped deposit of sediment built up by streams) from Fortymile Wash meets the 

broad, dry Amargosa River bed in the Amargosa Desert, south of the postclosure compliance 

location along the Yucca Mountain flow path (Figure 2-1). The Amargosa Farms area is not a 

hydrographic area defined on Figure 2-3; it lies within the southcentral portion of the 

Amargosa River Section. At present, extensive groundwater pumping for irrigation and 

drinking water occurs in Amargosa Farms. Groundwater withdrawal contributes more to 

losses within the Amargosa River Section than evapotranspiration. Groundwater 

pumping, mostly in the Amargosa Farms area, has been on the order of 17,600 acre-ft/yr 

[21.7 million m3

/yr] for the past several decades (DOE, 2014a, Table 2-1; NDWR, 2015). By 

comparison, evapotranspiration losses from the Amargosa River Section were estimated to be 

1,350 acre-ft/yr [1.67 million m3

/yr] (DOE, 2014a, Table 2-1). Due to groundwater pumping from 

1952 to 1987, the maximum drawdown of the water table was more than 9 m [30 ft] over a 

region more than 10 km [6 mi] across, east to west, centered on the irrigation wells distributed 
2-10 

Figure 2-4. Groundwater Flow Paths Inferred From Groundwater Geochemical 

Analyses (From SNL, 2007a, Figure B6-15). Flow Path 2, Which Merges 

With Flow Path 7, Represents the Direction of Flow From Yucca Mountain. 

Flow Path 2 and Flow Path 1 (Amargosa River) Converge Near the Location 

of the State Line Deposits. 
2-11 

around the Amargosa Farms area (Kilroy, 1991). Studies by the Bureau of Land Management 

(BLM) (BLM, 2010) reported the maximum drawdown of the water table as being more than 

90 ft [27 m] in 2003. At the southern end of the Amargosa Farms area, near the lower margin of 

the Fortymile Wash alluvial fan, are the State Line Deposits (also referred to as the Stateline 

deposits), fossil spring deposits that occur over an area 10–15 km [6–9 mi] long and 

approximately 5-km [3-mi] wide (Paces and Whelan, 2012). These deposits formed during past 

wetter climates; the youngest units date from more than 30,000 years ago. There are presently 

no springs near the State Line Deposits, although dense vegetation at nearby Franklin Well 

indicates a relatively shallow water table. The fossil deposits have a variety of complex 

geochemical compositions that represent the likely mixing of the Amargosa River and Fortymile 

Wash groundwater, with some inflow from the carbonate aquifer (Paces and Whelan, 2012). 

Within the State Line Deposits area, groundwater flow gradients in the vicinity of freshwater 

limestone deposits and bedrock structures indicate upward flow from the carbonate aquifer 

below the alluvial sediments of Amargosa Valley (Kilroy, 1991; Paces and Whelan, 2012). The 

groundwater flow direction in the regional 

carbonate aquifer in this area is west to 

southwest, in comparison to the southward 

flowing groundwater in the alluvial sediments of 

the Amargosa Farms area (Belcher and 

Sweetkind, 2010; DOE, 2014a). 

East of the Amargosa Farms area are Ash 

Meadows and Devils Hole, which are part of 

the Ash Meadows Basin hydrographic area 

(Figure 2-3). Ash Meadows Basin is the largest 

in the Central Death Valley Subregion. Flow in the carbonate aquifer is southwesterly to 

westerly in the Ash Meadows Basin, approaching the north-south and northwest trending 

high-angle faults in the Ash Meadows area. The faults cause much of the carbonate 

groundwater to be discharged in Ash Meadows as spring flows and through evapotranspiration 

(Winograd and Thordarson, 1975). Groundwater that is not discharged in Ash Meadows mixes 

to the south with flow from the volcanic and alluvial aquifers of the Alkali Flat-Furnace Creek 

Basin (Levich et al., 2000), as described below. 

West of Ash Meadows, there is a steep hydraulic gradient coincident with the north-south 

trending high-angle fault between the alluvial sediments of Amargosa Farms and the carbonate 

rock exposed at the ground surface in Ash Meadows (Belcher and Sweetkind, 2010). All of the 

present-day springs in Ash Meadows are in the area of the carbonate rocks. The surface 

exposure of carbonate rocks in Ash Meadows is in sharp contrast to the hydrologic conditions in 

the central portion of Amargosa Desert, where the carbonates are present far below the thick 

sequence of alluvial sediments. The steep hydraulic gradient across the north-south trending 

fault indicates little mixing of alluvial aquifer waters to the west with carbonate waters to the east 

in the present-day climate. Given the direction of the hydraulic gradient, any connection 

between the uppermost and underlying aquifers in this area is likely to be flow from the 

carbonate aquifer of Ash Meadows to the alluvial aquifer in the Amargosa Farms area. Further 

south, the waters of the two aquifers likely mix in the area between the Nevada-California state 

line and Alkali Flat (Figure 2-3). This is because the north-south trending high-angle fault 

appears to end further south near the Nevada-California state line (Belcher and Sweetkind, 

2010; Figure B-26). 

South of Amargosa Farms, the groundwater from the alluvial aquifer under Amargosa Farms 

can flow either southwestward or southward. Flow to the southwest is through the fractured 

Ash Meadows and Devils Hole 

Ash Meadows is a National Wildlife Refuge, a 

40-acre detached unit of Death Valley National 

Park. It contains more than 30 seeps and 

springs, including Devils Hole, fed by water from 

the carbonate aquifer. The caves at Devils Hole 

provide habitat for the only naturally occurring 

population of the endangered Devils Hole Pupfish 

(Cyprinodon diabolis).
2-12 

carbonate rock at the southeastern end of the Funeral Mountains to eventual discharge at 

Furnace Creek springs or evaporation in the Middle Basin of Death Valley (Figure 2-3). A 

possible alternative flow path southward from Amargosa Farms follows the dry bed of the 

Amargosa River. For this flow path, water moves in the thinning alluvial sediments along the 

Amargosa River towards Alkali Flat (also known as Franklin Lake Playa), where the 

groundwater intermittently discharges to the surface, or continues along the Amargosa River 

into the Shoshone-Tecopa Section of the Southern Death Valley Subregion. There is 

uncertainty in how the westward flowing carbonate aquifer interacts with the southward 

flowing alluvial aquifer of the Amargosa River Section, but geochemical data indicate that 

mixing occurs in the general area between the Nevada-California state line and Alkali Flat 

(Faunt et al., 2010a). 

Analysis of potential flow beyond Amargosa Farms, using a modification of the DVRFS model, 

indicates that in the absence of pumping in Amargosa Farms over the last century, the flow path 

would dominantly trend to the southwest under the eastern end of the Funeral Mountains 

(DOE, 2014a). The model used was based on Belcher and Sweetkind (2010), modified to 

include pumping data from 1913 to 2003 (SNL, 2014). Flow pathways can be identified in the 

model by releasing nominal “particles” at the postclosure compliance location and tracking their 

movement within the DVRFS. Adsorption, colloidal filtering, decay, or other mechanisms that 

would preclude the particles from moving with the water are not included in this analysis, so the 

particle tracking represents unrestrained movement of water-borne contaminants. In the model 

runs, 8,024 particles were released and tracked from the postclosure compliance location. The 

8,024 particles were derived from the release of 10,000 particles at repository locations in the 

Yucca Mountain Site-Scale Flow Model (SNL, 2009). The NRC staff has found DOE’s model for 

saturated zone flow in the vicinity of the repository and its integration of the multiple models to 

be acceptable as part of its safety evaluation (NRC, 2014a; Section 2.2.1.3.8). 

When historic data for pumping are considered in the DVRFS model, all particles are captured 

by the wells in Amargosa Farms (Figure 2-5, Pumping). When no pumping is included 

(the prepumping model, representing groundwater conditions prior to 1913), two pathways were 

identified (DOE, 2014a). The predominant path identified was approximately southward through 

Amargosa Farms and turning southwestward to westward beneath the Funeral Mountains to the 

springs at Furnace Creek and on to Middle Basin in Death Valley (Figure 2-5, No Pumping). A 

potential alternative, but less likely, path was identified by 2 particles (out of the 8,024) that 

traveled southward to and discharged at Alkali Flat. The flow path of the few particles tracked to 

Alkali Flat arises from the uncertainties in the model parameters, and may represent the 

possibility that a limited amount of water diverts from the predominant pathway. The particle 

tracking approach is a recognized method for understanding contaminant transport in hydrologic 

models (e.g., Faunt et al., 2010b). The NRC staff concludes that the use of particle tracking in 

the DVRFS model is a reasonable means of defining the potential paths that contaminants may 

follow, consistent with the flow fields of the DVRFS. Further information on the particle tracking 

model is given in Appendix A to this supplement. 

The groundwater flow path from Amargosa Farms southwest through the Funeral Mountains 

continues towards the springs near Furnace Creek and to Middle Basin in Death Valley. The 

likelihood of flow through the carbonate blocks at the southeastern end of the Funeral 

Mountains was identified through research conducted by the USGS (Belcher and Sweetkind, 

2010) and Inyo County (2007); (Bredehoeft et al., 2008), which defined the relatively permeable 

carbonate units within the Funeral Mountains. 
2-13 

Figure 2-5. Groundwater Flow Paths for Contaminants for the Pumping (Yellow) and 

the No Pumping (Fuchsia) Analysis Cases. The Flow Paths Are Delineated 

Using Particle Tracks and the Death Valley Regional Groundwater Flow 

System. Springs in the Region of Furnace Creek Are Shown as Open 

Circles. Modified From Belcher and Sweetkind (2010) and SNL (2009). 
2-14 

The likelihood of this southwesterly flow path differs from that identified in earlier DOE analysis 

(2008 SEIS; p.3-31), which indicated that the majority of the water moved instead to the south 

from the Amargosa Farms area, generally following the trace of the Amargosa River and 

discharging at Alkali Flat, but did not include the presence of highly transmissive carbonate units 

beneath the Funeral Mountains. Flow conditions in the absence of pumping in Amargosa 

Farms are not well characterized, so some possible flow towards Alkali Flat cannot be excluded. 

This alternate flow path is described further in the subsection on Alkali Flat and the Southern 

Death Valley Subregion. 

Funeral Mountain Section 

As previously noted, in the absence of pumping in Amargosa Farms, the more likely path for 

groundwater originating from Yucca Mountain is predominantly to the Funeral Mountain Section 

(Figure 2-3; labeled 3d) through the fractured carbonate rock of the southeastern part of the 

Funeral Mountains (the main flow path shown in Figure 3-1 of DOE, 2014a). Flow 

southwestward beneath the Funeral Mountains is likely in the fast-flowing fractured carbonate 

aquifer (Bredehoeft and King, 2010). This groundwater would then feed the springs of the 

Furnace Creek area of Death Valley. Water from these springs is currently used to support 

activities in the Furnace Creek area of Death Valley National Park. In the absence of human 

activity, discharges at these springs could reinfiltrate into the Death Valley alluvial fans and 

evaporate or transpire further downstream in the fans, or evaporate from the Middle Basin playa 

at the floor of Death Valley (Belcher and Sweetkind, 2010). 

The geochemistry of water at the Furnace Creek springs is similar to that at the springs of Ash 

Meadows, and to that of the regional carbonate aquifer generally (DOE, 2014a; 2008a). The 

chemistry of the water at the springs appears to have equilibrated (i.e., reflects the mineral 

content of) with the surrounding carbonate rock as indicated by the calcium, magnesium, and 

bicarbonate composition in the water. Further similarity of water discharging from the Furnace 

Creek springs to water discharging at Ash Meadows is shown in their content of rare earth 

elements (Johannesson et al., 1997). In addition, strontium isotope measurements also indicate 

that the groundwater interacted with older metamorphic or igneous rocks (Levich et al., 2000) in 

the central part of the Funeral Mountains. Furthermore, information from potentiometric and 

structural geology maps and water temperature measurements also support groundwater in the 

eastern regional carbonate aquifer flowing westward through Ash Meadows, under the southern 

part of the Amargosa Desert and the eastern end of the Funeral Mountains, to the springs at 

Furnace Creek. Geochemical and other data are consistent with the interpretation that under 

present pumping conditions at Amargosa Farms, the Furnace Creek springs do not include a 

significant component of water from the alluvial aquifer in that area. The data from the Furnace 

Creek springs are also consistent with water from the alluvial aquifer mixing with a larger 

volume of water flowing in the carbonate aquifer, or water that has equilibrated with the 

carbonate rocks of the Funeral Mountains. 

Evapotranspiration causes a much larger amount of groundwater loss than spring discharge in 

the Funeral Mountain Section. Three large springs (Texas, Travertine, and Nevares) at Furnace 

Creek together have a discharge of 2,300 acre-ft/yr [2.8 million m3

/yr] (DOE, 2014a; Table 2-1). 

The annual estimate of evapotranspiration for the Funeral Mountain Section is approximately 

10 times larger than this spring discharge (DOE, 2014a; Table 2-1). There is also a small 

amount of groundwater pumping in the Funeral Mountain Section, but this pumping does not 

occur near the groundwater flow path from Yucca Mountain, and thus does not impact the path 

for potential contaminants. 
2-15 

Alkali Flat and Southern Death Valley Subregion 

An alternative flow path for groundwater from Yucca Mountain is along the trace of the 

Amargosa River to Alkali Flat (DOE, 2014a). As previously noted, flow to Alkali Flat was 

considered more likely prior to updated information on aquifer units in the Funeral Mountains. 

This path is now seen as much less likely, but some flow in this direction cannot be ruled out, 

and discharge in Alkali Flat is considered as a potentially affected environment in 

this supplement. 

Based on the modeling results (DOE, 2014a), contaminant transport along the flow path beyond 

Alkali Flat is unlikely. Past Alkali Flat, the groundwater flow path follows the trace of the 

Amargosa River southward through the Shoshone-Tecopa Section and California Valley Section 

of the Southern Death Valley Subregion, and then continues along the Amargosa River as it 

turns westward through the Ibex Hills Section. Springs occur at several locations in the 

Shoshone-Tecopa and California Sections, leading to perennial flow in stretches of the river 

channel. Groundwater not lost to evapotranspiration, the springs along the river, or pumping 

from two wells near the town of Tecopa, continues to the flow path’s endpoint at Badwater 

Basin, the lowest-elevation playa and salt pan in Death Valley. 

The aquifer in Pahrump Valley, in the northeastern portion of the Southern Death Valley 

Subregion, does not directly interact with the alluvial-volcanic aquifer in the Amargosa River 

Section, but likely contributes groundwater flow to the lower (southern) part of the 

Amargosa River near Death Valley (Belcher and Sweetkind, 2010; Chapters C and D). The 

Pahrump Valley Section has extensive recharge in the surrounding mountainous areas as well 

as extensive pumping for agriculture in the Pahrump Valley. Under present and expected future 

wetter conditions, no contaminants from the repository would reach the aquifer in Pahrump 

Valley, based on the regional flow gradients (Belcher and Sweetkind, 2010). 

In the Shoshone-Tecopa, California Valley, and Ibex Hills Sections, more groundwater is lost 

through evapotranspiration {12,350 acre-ft/yr [15.2 million m3

/yr]} than through pumping 

(DOE, 2014a; Table 2-1). Wells in these areas extract only on the order of 27 acre-ft/yr 

[0.033 million m3

/yr] of groundwater (DOE, 2014a; Table 2-1). 

2.2.3 Effects of Groundwater Pumping on Flow 

In the 2002 EIS and 2008 SEIS, DOE provided a discussion of pumping in the DVRFS with 

additional detail for the Amargosa Desert. In the 2008 SEIS, DOE reported pumping rates 

based on irrigation estimates generated by the Nevada Division of Water Resources [(NDWR), 

see LaCamera et al., 2005]. Analyses in this supplement use pumping rates from DOE (2014a), 

which were generated by the USGS using a different approach for estimating irrigation 

(Moreo and Justet, 2008) that led to somewhat higher estimates of pumping 

rates. For example, for the period from 1994 to 2003, the pumping rates in the Amargosa 

Desert estimated by the NDWR are 72 to 84 percent of those estimated by the USGS. The 

different methods are described further in Section 2.4 (Groundwater Modeling). This section of 

the supplement provides a brief description of pumping rates for all water uses in the DVRFS, 

including the updated rates provided in DOE (2014a).
2-16 

Groundwater Pumping in DVRFS 

Significant pumping in the region started in 1913 and increased from the 1940s to 1960s. The 

pumping rates varied at approximately the same levels from the 1970s to the present-day for 

the DVRFS (Moreo and Justet, 2008; Figure 2). There are three major groundwater pumping 

areas within the DVRFS: Amargosa Valley, Pahrump Valley, and Penoyer Valley. In 

Amargosa Valley, an average of 16,800 acre/ft [20.7 million m3

] of groundwater was withdrawn 

annually from 1994 to 2003, of which 85 percent was used for irrigation and 13 percent was 

used for mining, domestic, and commercial purposes. Annual pumping variations are 

generally a result of crop and irrigation cycles. In Pahrump Valley, the largest groundwater 

withdrawal area in the DVRFS, annual pumping estimates ranged from approximately 20,000 to 

33,000 acre-ft [25 to 41 million m3

] from 1994 to 2003. Compared to Amargosa Valley, a larger 

fraction of the pumped water in Pahrump Valley was used for domestic purposes and the public 

water supply, rather than agriculture. Water used for irrigation ranged from approximately 

50 percent to 75 percent during the period 1993 to 2003, and this fraction decreased over time. 

Groundwater withdrawal in the Penoyer Valley (northeastern portion of DVRFS, outside of 

the area that influences groundwater flow from beneath Yucca Mountain) was about 

12,600 acre-ft/yr [15.5 million m3

/yr] and was used primarily for irrigation with the pumping rate 

holding relatively steady from 1994 through 2003. Over the entire DVRFS for 2003, about 

55,700 acre-ft [68.7 million m3

] of groundwater was pumped, of which 69 percent was used for 

irrigation; 13 percent for domestic; and 18 percent for public supply, commercial, and mining 

activities (Moreo and Justet, 2008). Comparable data for the entire DVRFS for more recent 

years are not readily available, but the available records for the area from the State of Nevada 

Division of Water Resources suggest that these volumes and fractions have not changed 

significantly (NDWR, 2015).

Groundwater Pumping in Amargosa Valley 

Historically, agricultural irrigation used 80 percent of annual groundwater withdrawal in 

Nye County, Nevada, which includes both Pahrump and Amargosa Valleys. Domestic and 

mining water supplies used the majority of the remaining 20 percent (DOE, 2014a). Outside of 

Pahrump Valley, the primary irrigation area is Amargosa Farms, in the south-central portion of 

Amargosa Valley. In the Amargosa Valley, total annual groundwater withdrawals averaged 

16,800 acre-feet [20.7 million m3

] from 1994 through 2003, with a minimum and maximum of 

14,100 and 21,100 acre-ft [17.4 and 26 million m3

] (Moreo and Justet, 2008). Estimates of 

pumping rates since 2003 are available from the State of Nevada’s Division of Water 

Resources (NDWR, 2015). For Amargosa Valley2

, the State of Nevada estimates of 

groundwater withdrawal rates from 2006 to 2012 range from 15,400 to 18,000 acre-ft/yr 

[19 million to 22.2 million m3

/yr] with an average of 16,700 acre-ft/yr [20.6 million m3/yr]. 

In its 2008 SEIS and in DOE (2014a), DOE suggested that present-day pumping rates for the 

Amargosa Farms areas may not be sustainable due to proximity to Devils Hole and the potential 

impact of pumping on water levels there. As DOE described in its 2002 EIS and 2008 SEIS, 

strict limits on groundwater withdrawal in the Ash Meadows area have been instituted to protect 

the water level in Devils Hole and the endangered Devils Hole pupfish. Withdrawals from within 

Ash Meadows are a very small portion (less than 1 percent) of the total withdrawals from the 

 

2

Amargosa Valley is referred to as the Amargosa Desert Hydrographic Basin (#230) in the State of Nevada Division 

of Water Resources designation system (NDWR, 2015). The DVRFS includes multiple hydrographic basins in the 

State of Nevada classification system, as well as groundwater basins in California. 
2-17 

Amargosa Desert Hydrographic Basin (DOE, 2008a). Information provided at a State of 

Nevada administrative hearing in 2007 (Taylor, 2008) showed that the water level in Devils Hole 

was within 0.7 ft [0.2 m] of the minimum threshold. Accordingly, the Nevada State Engineer 

issued an order (Taylor, 2008) that would deny any water rights applications within 25 mi 

[40 km] of Devils Hole, and any change applications that place the point of diversion to within 

25 mi [40 km] of Devils Hole (with some exceptions). This 25-mi [40 km] radius encompasses 

the Amargosa Farms area. The State Engineer’s order essentially limits future pumping rates in 

areas beyond Ash Meadows that may impact Devils Hole. These restrictions may also render 

the present-day pumping rates at the Amargosa Farms area unsustainable, as further analysis 

(SNL, 2009) indicates that the protected water level at Devils Hole could be reached by 2016, 

assuming only the continuation of current groundwater pumping. 

2.2.4 Past and Future Climates 

Understanding of possible future climates is important for the affected environment, as a climate 

that is cooler and/or wetter than the present-day climate can affect several aspects of 

groundwater flow, particularly groundwater levels, flow rates, and potential surface discharges. 

Recharge of the aquifers in the DVRFS by infiltrating water occurs predominantly at higher 

elevations on mountains and ridges where soils are thin, and along washes and riverbeds when 

water is flowing (DOE, 2008b, Section 2.3.1). Recharge is not evenly distributed over the 

DVRFS, and would change in a wetter climate. An increase in recharge (from increased 

precipitation and increased infiltration) would raise water levels in aquifers, which can cause 

surface discharge where the water table reaches the ground surface. 

In the southern Great Basin, precipitation and temperature are the two most important climate 

variables affecting groundwater conditions (e.g., Garfin et al., 2014). DOE developed 

projections that consider potential cooler/wetter future climates as part of its assessment of 

repository performance (DOE, 2008b). The climate projection developed by DOE for the 

Yucca Mountain site can be appropriately applied to the entire DVRFS because it is based on 

regional information on past climates and a general understanding of how similar conditions can 

be expected to occur in the future. 

Reconstructions of regional past climates in the southern Great Basin, including the 

Yucca Mountain region, show patterns of periods that are relatively hot and dry (similar to 

present conditions) and periods that are relatively cooler and wetter (e.g., Reheis et al., 2008). 

Wetter phases in the region, represented by high stands of paleolakes, do not necessarily 

correspond to the full glacial conditions known from global reconstructions, but have occurred 

during glacial transition periods (e.g., Smith and Street-Perrott, 1983). 

These reconstructions of past climate states are the best indicators of expected future climates. 

Using paleoclimate reconstructions as a basis, DOE has defined three climate states in addition 

to the present-day interglacial climate that are expected to occur over the next million years 

(DOE, 2008b, Section 2.3.1). These are (i) a monsoonal climate that is warm and wetter 

compared to the present-day interglacial climate, with a shift in the seasonality of precipitation; 

(ii) a glacial-transition climate with cooler and wetter conditions compared to the present-day 

climate; and (iii) a full-glacial climate, which represents the maximum extent of cool conditions 

recorded in paleorecords. DOE included the interglacial, monsoonal, and glacial-transition 

climate states in its performance assessment for the repository over the first 10,000 years 

following permanent closure, and used a prescribed deep percolation rate (the amount of 

water reaching the repository) for the remainder of the one million year period, as provided in 
2-18 

10 CFR 63.342 (DOE, 2008b, Section 2.3.1.2). The NRC staff found DOE’s model for future 

climate states to be acceptable as part of its safety evaluation (NRC, 2014a; Section 2.2.1.3.5). 

For this supplement, the most significant considerations for groundwater are the overall flow 

paths and flow rates, and potential changes in the water table that could affect locations of 

surface discharge, as these can affect contaminants from the repository in the aquifer and at 

surface discharge locations. For these effects, the present day interglacial (hot and dry) and 

glacial or glacial-transition (cooler and wetter) climates represent the range of potential climate 

effects on groundwater in the DVRFS. A monsoonal climate is not considered further in this 

supplement because the effects on groundwater of that climate state fall between those of the 

present-day and cooler/wetter climate states (i.e., a warm, wet climate would have less impact 

on groundwater than a cooler/wetter climate). The effects of the cooler/wetter climate on the 

impacts addressed in this supplement are included in several aspects of the NRC staff’s 

analysis. The potential climate impacts on repository releases are captured through the use of 

the DOE performance assessment outputs for contaminants reaching the postclosure 

compliance location (which includes the effects of increased water flow reaching the repository). 

Adjustments to groundwater velocity are used to incorporate the higher groundwater flow rates 

expected in a cooler/wetter climate. Potential changes in surface discharge locations are 

included by considering the fossil deposits that formed during past cooler and wetter periods. 

Appendix A provides details on the methods used to evaluate the effects of different 

climate states. 

The analysis in this supplement makes no assumptions about the timing of the potential future 

climate states, only that such conditions can be expected to occur during the one-million-year 

period considered in this supplement. Notably, key indicators of past wetter climates, such as 

deposits from former high lake levels and past surface discharges of groundwater 

(paleodischarge sites), provide useful insight into changes in groundwater conditions regardless 

of when they occurred. The analysis in this supplement assumes that potential releases of 

contaminants from the repository can occur independently of the climate state, so the timing of 

changes in climate has no effect on the impact analysis. 

The principal changes to groundwater in the Yucca Mountain region from cooler and wetter 

climates in the future are potentiometric surfaces (water table in the unconfined, upper aquifer) 

that are higher than present day conditions, changes in the flow paths, and changes to flow 

rates. One consequence of a shift to a cooler/wetter climate is that elevated water tables could 

lead to discharge at new locations. Present-day types of natural discharge are described in 

Section 2.3, including potential locations of discharge under a cooler/wetter climate state 

(Section 2.3.4). A second consequence is the possible alteration of pumping rates and irrigation 

strategies; in a cooler/wetter climate, less irrigation water would be needed to maintain the 

same set of crops. A third consequence is that the local or regional groundwater quantity, flow 

rates, and flow distributions may change due to changes in hydraulic gradients and the water 

table position. The consequences of this uncertainty in pumping rates is considered in 

Section 2.5 and in Chapter 3. Potential changes to groundwater flow in future climates are also 

discussed in Section 2.4. 

Presently available information about human-induced climate change from the release of 

greenhouse gases indicates that, for this region, the most notable effects on groundwater would 

be increased heat and aridity in the near term, and over longer term, potentially extending the 

duration of the present-day interglacial climate (hot and dry) for longer than it would persist in 

the absence of human-induced change (e.g., Garfin et al., 2014). The principal effects of a 

climate that is warmer and drier than the present-day climate is to delay the release and 
2-19 

transport of contaminants from a repository. This is because releases depend on water entering 

the repository by infiltration and percolation, and transport depends on the amount and rate of 

water flow through the unsaturated and saturated zones (DOE, 2008b, Enclosure 8; 

NRC, 2014a, Section 2.2.1.3.5). Therefore, the impacts from potential human-induced climate 

change are captured within the range of conditions for climate and water use considered in 

this supplement.

2.3 Surface Discharge Environments 

Present-day natural surface discharge sites from the groundwater system in the desert of the 

southern Great Basin cover a spectrum of types, from seeps onto the ground surface (springs) 

to wet or dry playas. Groundwater discharges as springs where the water table reaches the 

ground surface. Wet playas occur in low areas where the water table is below the ground 

surface to depths of less than 5 m [16 ft] (Reynolds et al., 2007). Dry playas occur where the 

water table is at greater depths {greater than 5 m [16 ft]}; though at much greater depths, and 

depending on the soil type, evaporation becomes minimal. Springs discharging to the ground 

surface may reinfiltrate downstream. Surface discharges in desert environments can vary 

seasonally and year to year, depending on precipitation and other factors. Springs or streams 

in desert environments where water is always flowing are referred to as perennial. Those that 

vary between wet and dry periods are referred to as ephemeral. 

In a wet playa, capillary action (water moving through pores in the soil, or wicking) brings water 

to the surface or near-surface, where evaporation causes dissolved material in the water to 

precipitate as mineral deposits within or on existing sediments. Texturally, soils found at wet 

playas differ from those at dry playas (Reynolds et al., 2007). Mineral deposits near the surface 

in wet playas are described as fluffy, puffy, and soft. Wind erosion can redistribute the 

finer-grained minerals. Soils at dry playas, however, are described as generally compact and 

hard. The potential for wind erosion, and thus wind redistribution of deposited minerals, is 

relatively low at dry playas (Reynolds et al., 2007). Spatial and temporal variations add 

complexity to classifying discharge locations. For example, low-lying areas may have springs 

and a complex distribution of wet and dry playas. Seasonally or from year to year, features at a 

discharge location may change between dry or wet playas, or to springs or standing water. The 

distinction between wet and dry playas is important for the analysis of impacts in Chapter 3 of 

this supplement because the wind-driven redistribution of surface material that could contain 

contaminants deposited from groundwater depends on the nature of the deposits. As noted 

above, redistribution of precipitated material by wind is more likely from wet playas than from 

dry playas. 

Geographically, locations of natural discharge sites fall into two categories. The first type is 

seeps (springs) and focused evapotranspiration along alluvial fans or faults. The second type 

occurs where there is a confluence of the water table with low-lying areas, such as the bottom of 

a valley. At the first type, water may either evapotranspirate or flow downslope and infiltrate 

back into the ground. At the second type, water evaporates, or transpires if plants are present. 

As previously noted, the chemistry of spring water reflects the rock through which the water has 

flowed. Water equilibrated with carbonate rock is of a calcium-magnesium-bicarbonate 

composition and generally contains more dissolved chemicals than water equilibrated with 

volcanic rock or volcanic-derived sediments, which has higher concentrations of sodium, 

potassium, and silica. This water chemistry plays a role in what minerals precipitate as the 

groundwater evaporates at a discharge site, which in turn can affect what contaminants could 

be present in surface deposits. 
2-20 

2.3.1 Ecology at Surface Discharge Sites 

The region south of Yucca Mountain, where the surface water discharge locations discussed in 

this supplement are located, is within the Mojave Basin and Range ecoregion (Bryce et al., 

2003; Griffith et al., 2011). The Mojave Basin and Range ecoregion is composed of broad 

basins and scattered mountains that are generally lower, warmer, and drier than those of the 

Central Basin and Range located north of the Mojave Basin and Range ecoregion (north of 

Beatty, Nevada). The broader Mojave Basin and Range ecoregion is further subdivided into 

smaller ecoregions: State Line/Franklin Well, Ash Meadows, and Alkali Flat, which are located 

within the Amargosa Desert ecoregion, and Furnace Creek springs and Middle Basin, which 

are located within the Death Valley/Mojave Central Trough ecoregion (Bryce et al., 2003; 

Griffith et al., 2011). 

The landscape in this region consists of north-south trending mountains separated by valleys. 

The creosote bush (Larrea tridentata)—white bursage (Ambrosia dumosa) association covers 

approximately 70 percent of the Mojave Desert, especially on lower valley floors 

(MacMahon, 2000; p. 292). These two desert scrub plants dominate much of the lower slopes 

and alluvial fans at the base of the mountain ranges and extend down into many of the 

inter-mountain basins. Plant species typically found with creosote bush—white bursage 

association in the Mojave Desert include Shockley’s goldenhead (Acamptopappus shockleyi), 

Anderson's wolfberry (Lycium andersonii), range ratany (Krameria parvifolia), Mojave yucca 

(Yucca schidigera), California jointfir (Ephedra funerea), spiny hopsage (Grayia spinosa), and 

winterfat (Krascheninnikovia lanata). Blackbrush (Coleogyne ramosissima) and Joshua tree 

(Yucca brevifolia)–dominated vegetation series are present on mid-elevation mountains and 

hillsides. On alkaline flats, vegetation transitions to species dominated by saltbush 

(Atriplex ssp.), saltgrass (Distichlis stricta), alkali sacaton grass (Sporobolus airoides), and 

iodine bush (Allenrolfea occidentalis) or pickleweed (Salicornia spp.) (Bryce et al., 2003). 

The mixed saltbush-greasewood (Sarcobatus vermiculatus)-dominated vegetation series is 

common on the basin floor in Death Valley (MacMahon, 2000; p. 267). Iodine bush and 

pickleweed-dominated vegetation series and saltgrass-dominated vegetation series are present 

on wet basin-fill and lacustrine deposits. 

Wildlife species often use multiple habitat types throughout their life cycle and move within 

corridors or between patches that contain acceptable habitat. As an example, riparian areas and 

wetlands are key features for a large number of wildlife species throughout the Mojave Basin 

and Range ecoregion. Some animals, endemic species, survive only in a particular area such 

as within the subdivided Amargosa Desert ecoregion. Other animals live throughout the region, 

while others pass through the region during migration. Common terrestrial wildlife found in the 

Amargosa Desert and Death Valley/Mojave Central Trough ecoregions include mammals such 

as the desert bighorn sheep (Ovis canadensis), desert kit fox (Vulpes macrotis), coyote 

(Canis latrans), ground squirrels [e.g., white-tailed antelope squirrel (Ammospermophilus 

leucurus), bats (e.g., California myotis (Myotis californicus) and the western pipistrelle 

(Parastrellus Hesperus)], desert cottontails (Sylvilagus audobonii), black-tailed jackrabbit 

(Lepus californicus), and rodents (e.g., kangaroo rat (Dipodmys spp.) (Digital Desert, 2015). 

Birds found in these areas include a number of species of eagles, hawks, owls, quail, 

roadrunners, finches, warblers and orioles. Reptiles include the desert tortoise 

(Gopherus agassizii) and several species of rattlesnake and lizard. Insects (e.g., butterflies 

and moths, tarantula hawk wasps, beetles, ants, grasshoppers), and arachnids (e.g., scorpions, 

tarantulas, wolf spiders, crab spiders) are also an important part of the desert ecosystem. 
2-21 

Significant landscape changes may occur within the Mojave Basin and Range ecoregion in the 

short term and long term in response to climate change. Modeling the next five decades 

suggests that in response to possible near-term climate change, the lowest-elevation basins 

throughout the ecoregion, where surface water discharge locations are currently or are 

expected to occur, could transition from warm desert scrub into relatively barren areas, the 

expansion of some desert playas, and the slow expansion/transformation of the mixed 

salt-desert scrub vegetation type (Comer et al., 2013). Areas currently dominated by Joshua 

tree and blackbrush-scrub type vegetation could transition to a creosote bush-dominated scrub 

vegetation type. In a similar manner, a future cooler/wetter climate will lead to changes in the 

type and abundance of vegetation. Changes in species composition, community types, and 

distribution ranges can be expected, with pinyon-juniper woodlands and other less-arid 

Great Basin species likely to become more prevalent in the region during this climate state 

(DOE, 2008b, Section 2.3.1.3.2.1.5; NRC, 2014a, Section 2.2.1.3.5). The exact mechanisms 

for these transformative vegetation changes will likely vary by type and location with varying 

speed and intensity. 

The linkages between key climate variables and ecosystem dynamics across the Mojave Basin 

and Range are not well understood. While the long-term climate-related trends are highly 

unpredictable, and the resulting ecosystem dynamics are speculative (Comer et al., 2013), the 

details of particular ecological changes are not necessary for assessing the impacts considered 

in this supplement. As discussed in Chapter 3, the impacts at the discharge locations are not 

dependent on the specific nature of the vegetation that is present, but are instead driven by the 

amount of surface discharge, the concentration of potential contaminants, and the type of 

discharge environment (e.g., springs, playa, or salt pan). 

Ecological characteristics of specific sites are discussed in the subsequent sections. 

2.3.2 Cultural Resources at Surface Discharge Sites 

The NRC staff has determined that historic and cultural resources may be located in or around 

current surface discharge areas, described in Section 2.3.3, or in paleodischarge areas 

(which are also potential future discharge locations), described in Section 2.3.4. Previous 

analysis of cultural resources by DOE in its EISs for the repository at Yucca Mountain focused 

on the repository site and the surrounding controlled area. In its 2002 EIS, DOE identified as its 

region of influence for cultural resources “the land areas that would be disturbed by the 

proposed repository activities (as described in Chapter 2) and areas in the analyzed land 

withdrawal area where impacts could occur” (DOE, 2002; Section 3.1.6). DOE updated this 

information in Section 3.1.6 of the 2008 SEIS, which states that DOE widened the region of 

influence to include land that DOE had proposed for an access road from U.S. Highway 95, and 

land where DOE would construct offsite facilities. Section 3.1.6 of the 2008 SEIS also notes 

that DOE had developed a draft programmatic agreement among DOE, the Advisory Council on 

Historic Preservation, and the Nevada State Historic Preservation Office for cultural resources 

management related to activities that would be associated with development of the proposed 

repository (DOE, 2008a). In February 2009, DOE finalized its programmatic agreement 

(DOE, 2009b). The area covered by the agreement “includes all site activities conducted by 

[DOE] and its contractors for the licensing and development of Yucca Mountain as a repository 

for disposal of spent nuclear fuel and high-level radioactive waste that have the potential to 

affect historic properties, and that are located within the boundaries of the Yucca Mountain 

Project Operator-Controlled Area.” 
2-22 

The affected environments considered in this supplement are outside of the nominally 

controlled area considered by DOE in its previous assessments, and could include historic and 

cultural resources. For example, members of the Timbisha Shoshone Tribe reside on a 

314-acre [1.27-km2

] parcel of trust land located in the Furnace Creek area of Death Valley, 

near Furnace Creek springs. As previously noted, the tribe has federally appropriated rights 

to 92 acre-feet per year [0.113 million m3/yr] of surface and groundwater in the area 

(DOE, 2014a; 16 U.S.C. 410aaa). Section 3.3 is the NRC staff’s consideration of impacts on 

cultural resources. 

2.3.3 Present-Day Discharge Sites 

This section describes present-day sites of natural surface discharge near or along the flow path 

from Yucca Mountain to Death Valley in terms of the groundwater flow pathways discussed in 

Section 2.2. Table 2-1 provides annual estimates of surface discharge for six different areas 

discussed in the text. Evapotranspiration and spring discharge in arid environments can be 

difficult to measure or estimate and, thus, leads to some uncertainty. For example, a 

spring discharge rate of 5 cubic feet per second (cfs) [4.4 × 106 m3 annually] is estimated by 

Jensen et al. (2004), whereas a rate of 3.2 cfs [2.83 × 106 m3 annually] is estimated by 

Belcher and Sweetkind (2010). For consistency, all estimates of discharge in Table 2-1 are 

taken from Belcher and Sweetkind (2010). This approach is conservative, because using the 

lower rate of discharge results in a higher potential contaminant concentration for the same 

amount of contaminants in the smaller water volume. Figure 2-6 shows the discharge locations 

discussed in the following sections. 

As described in Section 2.2.2, the predominant flow path is southwestward from 

Amargosa Farms, beneath the eastern end of the Funeral Mountains. Another path is 

southward from Amargosa Farms towards Alkali Flat. In addition to these, other sites of 

minor discharge in the Amargosa Farms area and areas immediately south are discussed in 

this section. 

Discharge Locations along the Flow Path Southwest from Amargosa Farms 

The springs at Furnace Creek in Death Valley (Figure 2-6) discharge groundwater that has 

flowed under the Funeral Mountains. The springs in the Furnace Creek area appear to be 

controlled by major structural features (Fridrich et al., 2012). The Texas, Travertine, and 

Nevares Springs at Furnace Creek are surrounded by shrubs and grasses. The discharge is 

predominantly a calcium-magnesium-bicarbonate water reflective of the regional carbonate 

aquifer. Engineered structures have been built at several of the Furnace Creek springs to 

manage the water for use in Death Valley. Section 2.5.1 provides more information on 

water use. 

Middle Basin (Figure 2-6) is a local low point in Death Valley that is down gradient from Furnace 

Creek. Groundwater that does not discharge at the three Furnace Creek springs, or that 

re-infiltrates after discharging from the springs, flows down an alluvial fan to the salt pan at 

Middle Basin. Along the alluvial fan, there are numerous small springs surrounded by a variety 

of desert shrubs, trees, and grasses. Direct evaporation occurs in the salt pan at the bottom of 

the alluvial fan. As a salt pan, Middle Basin is a low point or depression in the ground in which 

saline water has evaporated, leaving salt deposits. 
2-23 

Discharge Locations along the Flow Path South from Amargosa Farms 

Alkali Flat, also known as the Franklin Lake Playa, is a broad area south of Amargosa Farms 

along the dry bed of the Amargosa River (Figure 2-6). Deposits at the site reflect intermittent 

spring discharge and wet and dry playas (Reynolds et al., 2007). Salt pan, soft and fluffy wet 

playa deposits, and hard and compacted dry playa deposits are distributed near or intermixed 

with channel deposits at the confluence of Carson Slough (an ephemeral stream that 

intermittently flows south from Ash Meadows) and the Amargosa River. The present-day water 

table at Alkali Flat varies from 0 to 4 m [0 to 13 ft] below the ground surface. Water is supplied 

to the flat from Ash Meadows along Carson Slough and from the Amargosa River. Surface 

discharge is dominated by loss to evaporation and, to some extent, transpiration by scattered 

low scrub vegetation, although intermittent surface flow can occur during brief wetter periods 

such as major rainfall events (e.g., Beck and Glancy,1995; Tanko and Glancy, 2001). Surface 

water in the wet playa portion primarily flows off the playa and continues along the 

Amargosa River bed (Reynolds et al., 2007); little standing water has been observed in this 

area. Chemistry of the water varies widely, from dilute to highly saline. Water in the thin alluvial 

sediments is confined to those sediments. Two springs in the northern part of the flat have 

relatively dilute water; water emanating from a well and from a spring have 1,000 mg/l [ppm] 

and <5,000 mg/l [ppm], respectively, of total dissolved solids. By contrast, total dissolved solids 

reaches 80,000 mg/l [ppm] in water from the wet playa portions of the flat. The water at Alkali 

Flat is of insufficient quantity and too saline to be of beneficial human use (Czarnecki and 

Stannard, 1997). 

Most of the surface of Alkali Flat is not vegetated (Czarnecki and Stannard, 1997). Vegetated 

areas are limited mainly to along the braided river channel with relatively lower salt content. 

About 1 to 5 percent of the total surface area of the playa {total area roughly 16 km2

 [6 mi2]} 

consists of sparsely distributed mounds primarily covered with greasewood, seepweed 

(Suaeda fruticosa), and saltbush. Small quantities of saltgrass are concentrated near the few 

springs and seeps at the northern and eastern playa margins. 

The Shoshone and Tecopa portions of the Amargosa River, south of Alkali Flat, are perennial 

under the present-day climate (Menges, 2008). Water that does not discharge at Alkali Flat 

flows in the alluvial sediments of the Amargosa River valley. The quantity of groundwater 

discharge is sufficient to maintain a flowing river year-round for a short stretch near Shoshone 

Table 2-1. Annual Discharge Estimates for Natural Discharge Locations. In Most of the 

Areas, Estimates of Discharge Rates Could Not Readily Separate 

Contributions From Evapotranspiration and Spring Flow. Ash Meadows Data 

Is Provided for Comparison. [Data From Belcher and Sweetkind (2010), 

Tables C–1 and C–2.] 

Discharge Area 

Prominent 

Springs 

Present? 

Evapotranspiration plus 

Spring Flow 

(millions of m3

) 

Spring Flow 

(millions of m3

) 

Alkali Flat-Franklin Lake — 1.23 — 

Shoshone-Tecopa Yes 10.5 

Furnace Creek Yes — 2.83 

Middle Basin of Death Valley — 2.42 — 

Franklin Well — 0.43 — 

Ash Meadows Yes 22.2 — 
2-24 

Figure 2-6. Location of Natural Groundwater Discharge Areas, Including Springs and 

Playas, in the Death Valley Regional Groundwater Flow System. Modified 

From Belcher and Sweetkind (2010). 
2-25 

and a longer stretch {about 8 km [5 mi]} south of Tecopa, although Zdon and Associates (2014) 

report surface flow in the channel for a 40-km [25-mi] stretch of the Amargosa River. The 

source water for the springs in this section is primarily the regional carbonate aquifer system but 

may include a small component that flows along the relatively shallow alluvial system beneath 

the river channel from Alkali Flat to Shoshone (Zdon et al., 2015; Zdon and Associates, 2014, 

2015; Davisson and Associates, 2014). Based on geochemical analyses of water from the 

springs (Zdon et al., 2015; Zdon and Associates, 2014; Larsen et al., 2001), the source of the 

groundwater for the springs is the Spring Mountains and the Kingston Range, and from the 

carbonate aquifer that also supplies water to Ash Meadows. 

Other Discharge Locations in the Amargosa Farms Area 

Evidence of paleosprings in the Amargosa Farms area is found in the State Line Deposits, 

which extend southward from the Amargosa Farms area and span a section of the dry 

Amargosa River bed. The surface exposures of these deposits consist of a complex distribution 

of Holocene playa sediments and older freshwater limestone rocks interspersed with channel 

and alluvial fan deposits (Kilroy, 1991). At present, this area is not likely to have significant 

water loss by evapotranspiration, as described in Belcher and Sweetkind (2010, Chapter C), 

except for the limited Franklin Well area, as discussed below. The water table in the State Line 

Deposits area varies from 1.8 to 10 m [6 to 33 ft] below the surface, based on well 

measurements from the 1980s (Kilroy, 1991; Paces and Whelan, 2012). The water table is 

closest to the ground surface immediately to the southwest of the deposits, in the vegetated 

Franklin Well area. In the area of the State Line Deposits, the water table depth is within the 

range of a potential wet playa environment. Groundwater drawdown from pumping in the 

Amargosa Farms area over the last century may have extended to parts of the State Line 

Deposits area, and thus, in the absence of pumping at Amargosa Farms, evaporation may 

occur over a larger area in the State Line Deposits wherever the water table is within 5 m [16 ft] 

of the ground surface (following the delineation by Reynolds et al., 2007). The State Line 

Deposits area could be a potential minor discharge location for water flowing from 

Yucca Mountain under the present-day climate (or in a future cooler/wetter climate), but only if 

pumping in the Amargosa Farms area is significantly reduced. However, there is no evidence of 

recent springs in the State Line area, and the youngest dated State Line spring deposits formed 

approximately 30,000 years ago (Paces and Whelan, 2012). 

The Franklin Well area is a small linear band along the base of the alluvial fan from the southern 

end of Funeral Mountains and the Amargosa River bed. Adjacent to the State Line Deposits, 

the Franklin Well area includes an approximately 8 km [5 mi] section with locally dense 

vegetation and associated evapotranspiration. Belcher and Sweetkind (2010) estimated a small 

amount of evapotranspiration discharge for this area (Table 2-1), but gave no further 

description. The specific source of the water in this narrow zone is not well defined. Possible 

sources include northward flowing groundwater in the alluvial fan bordering the Funeral 

Mountains, eastward flowing groundwater along the Amargosa River channel, and southward 

flowing groundwater in the alluvial aquifer under the Amargosa Farms area (Belcher and 

Sweetkind, 2010; Figure C–2). The southward flowing groundwater in the alluvial aquifer under 

Amargosa Farms includes groundwater from beneath Yucca Mountain. 

The woodland vegetation of the Franklin Well area is comprised mostly of mesquite 

(Prosopis spp.), saltcedar (Tamarix spp.), and desert willow trees (Chilopsis linearis), with 

some meadow grasses and shrubs. The dense to moderately dense grassland vegetation 

in the area is primarily saltgrass and/or short rushes with an occasional tree or shrub 

(Laczniak et al., 2001). 
2-26 

Ash Meadows 

Ash Meadows is in the neighboring basin to the east of Amargosa Farms and, as such, is not a 

discharge location for groundwater flowing from Yucca Mountain. Ash Meadows is a large area 

of wetlands and pools fed by springs. The springs are surrounded by a broad area of grass 

meadows interspersed with moderately dense to sparse stands of trees and shrubs. The 

source of water to the springs is the regional carbonate aquifer, which is fed by recharge from 

the Spring Mountains, which flows from the east and northeast towards Ash Meadows 

(Belcher et al., 2012). The groundwater flowing from the Ash Meadows area mixes with the 

Amargosa River flow path, well south of Yucca Mountain, along Carson Slough and Alkali Flat, 

as described above. 

Ash Meadows is a well-studied desert wetland ecosystem encompassing over 23,000 acres 

[93 km2

] of spring-fed wetlands surrounded by sparse, relatively dry grassland interspersed with 

sparse to moderately dense stands of trees and shrubs (Belcher et al., 2012). According to 

Laczniak et al. (1999, pp. 7–8): 

Areas influenced by local springflow include groves of ash (Fraxinus velutina var. 

coriacea), cottonwood (Populus fremontii), willow (Salix exigua), and mesquite 

(Prosopis glandulosa torreyana and P. pubescens); thick stands of saltcedar 

(Tamarix aphylla, T. parviflora, and T. ramosissima); expansive meadows of 

saltgrass, wire-grass (Juncus balticus, J. cooperi, and J. nodosus), and 

bunch grass (Sporobolus airoides); and open marshland of cattails 

(Typha domingensis), reeds (Phragmites australis), and bulrush 

(Scirpus robustus). More typical Mojave Desert flora, primarily sparse covers of 

healthy creosote bush (Larrea tridentata), saltbush and desert holly 

(Atriplex hymemelytra), dominate upland areas not influenced by local 

spring discharge. 

In summary, the principal natural discharge site under present conditions for 

groundwater potentially contaminated by releases from a repository at Yucca Mountain 

is in the Furnace Creek/Middle Basin of Death Valley. Minor discharge sites for 

contaminants include Alkali Flat and the area of the State Line Deposits. The 

present-day extensive surface discharge in nearby Ash Meadows is fed from a separate 

basin in the DVRFS, and is not a discharge location for potential repository 

contaminant releases. 

2.3.4 Paleodischarge Sites 

During cooler/wetter climates, groundwater would continue to discharge at the present-day 

sites, and potentially, at additional sites in Amargosa Valley and along the flow path from 

Yucca Mountain to Death Valley. The volume of future groundwater discharges at present-day 

sites would likely increase, as would the area of wet playas. Evaporation may decrease due to 

cooler temperatures. New discharge sites would likely form as the water table rises. 

Evidence of paleodischarge sites found in Amargosa Desert and across the DVRFS serve both 

to identify possible future discharge locations and to constrain the potential increases in the 

elevation of the water table. These sites provide calibration targets3

 for groundwater flow 

 

3

Calibration targets are known information used to constrain other less well-known inputs in a groundwater model
2-27 

models and are useful in identifying or precluding other potential discharge sites. Notably, 

results of numerical groundwater modeling, as discussed in Section 2.4, suggest that even 

though flow rates and discharge locations may vary, the flow path does not significantly change 

between drier and wetter periods.

Amargosa Desert Sites 

Data derived from fossils, rock types, mineralogy, and chemistry at discharge sites across the 

Amargosa Desert provide consistent indicators of the timing, flow history, and characteristics of 

these discharge sites (Paces and Whelan, 2012; Paces et al., 1997). The State Line Deposits 

and several Crater Flat area deposits were discharge sites under past cooler/wetter climates. 

These are representative of potential discharge sites along the present-day and potential future 

groundwater path from Yucca Mountain under a cooler/wetter future climate. 

As described in Section 2.2.2, the State Line Deposits area (Figure 2-6) falls directly along the 

path of groundwater flowing from Yucca Mountain (DOE, 2014a). Observations from the 

discharge deposits show a complex interplay of surface flow and spring discharge in the 

southern part of the Amargosa Desert (Belcher and Sweetkind, 2010). The discharge deposits 

indicate that the groundwater generally reflects the mineral content of the volcanic-derived 

alluvial sediments of Amargosa Valley. The deposits also indicate contributions from (i) the 

lower carbonate aquifer, as indicated by the freshwater limestone deposits and (ii) older 

metamorphic rocks to the south in the Funeral Mountains, as indicated by the strontium isotopic 

composition (Paces and Whelan, 2012; Paces et al., 1997). Based on the areal distribution of 

discharge deposits at the ground surface and at depth, and the present-day topography, the 

water table rise in a cooler/wetter climate would likely be no more than 30 m [98 ft] in this part of 

the southern Amargosa Desert (Paces and Whelan, 2012). Information from the fossils, 

mineralogy, and stratigraphy (relative relations of the rock layers) indicates that these ancient 

discharge sites existed in a diverse wetland environment fed by springs and perennial or 

seasonal flow along the Amargosa River (Paces and Whelan, 2012). This wetland environment 

included wet ground, seeps, marshes, flowing channels, and open pools. Surrounding areas 

supported phreatophyte (deep-rooted) vegetation with associated discharge by 

evapotranspiration. Isotopic dating of the deposits indicates that the springs were active at 

several times during the transition into the last glacial maximum, with measured ages of roughly 

100,000 and 40,000 years before present. 

Several small areas of paleodischarge deposits, marked in Figure 2-6, occur northeast of the 

State Line Deposits, but west of Ash Meadows. These are much more limited in extent and 

have not been studied in as much detail as the State Line Deposits. Given their locations, these 

deposits are more likely related to groundwater from Ash Meadows during past wetter climates, 

rather than the southward flowing volcanic-alluvial aquifer system in Fortymile Wash. The 

present depth-to-water table at this location is greater than the possible water table rise in the 

alluvial aquifer during wetter climate conditions (Paces and Whelan, 2012). For these reasons, 

these locations are not likely to represent potential future discharge sites for groundwater from 

the Yucca Mountain flow system.

Three paleodischarge deposits are present at the southern end of Crater Flat (Figure 2-6), on a 

smaller scale and with much less carbonate deposition compared to the State Line Deposits 

(Paces and Whelan, 2012). All three deposits have geochemical signatures of water 

equilibrated with alluvial sediments derived from tuff (volcanic rock) and a lesser amount of 

carbonate rock (Paces et al., 1997). Differences in the stratigraphy at the three sites, together 

with those in the State Line Deposits area, suggest that these deposits formed in local ponds 
2-28 

and marshes, rather than in a large lake across the Amargosa Desert (Paces et al., 1997). 

Diatomites (deposits composed of fossil diatoms, microscopic organisms with a silica shell) are 

present at all the Amargosa discharge sites, though only the Lathrop Wells site has a thick 

sequence. The presence of diatomites, along with other fossils (shells of ostracodes and 

mollusks) indicate a paleoenvironment of open water such as flowing springs, pools, and 

wetlands (Paces and Whelan, 2012). The three Crater Flat deposits occur at elevations of 

790 to 835 m [2,591 to 2,739 ft] (Paces and Whelan, 2012). These elevations indicate the water 

table elevation exiting Crater Flat during the wetter periods. Nye County research wells indicate 

that the present-day depth to the water table ranges from 8 to 31 m [2.4 to 9.5 ft] at the three 

paleodischarge sites (Paces and Whelan, 2012). Importantly, geochemical data and age 

determinations indicate flow at the Crater Flat paleodischarge locations was active during 

roughly the same time periods as at the State Line location (Paces and Whelan, 2012; 

Paces et al., 1997), indicating that the discharge was likely related to regional climate effects. 

However, none of the three Crater Flat sites is located along a present or past flow path from 

Yucca Mountain, based on an analysis of the elevations and potential extent of water table rise 

at Yucca Mountain (Paces et al., 1997; SNL, 2007a). Instead, particle tracking model results for 

future wetter climates indicate that flow from the northwest below Crater Flat was the likely 

source for the Crater Flat discharge deposits (Winterle, 2005). 

Alkali Flat to Death Valley 

The Carson Slough and Amargosa River flow systems (groundwater and surface water) feed 

Alkali Flat (Franklin Lake Playa). Evidence from Devils Hole shows that the water table 

fluctuated between 5 and 9 m [16 and 30 ft] higher at Ash Meadows during the glacial periods of 

the last 116,000 years (DOE, 2014a). This rise, along with possible perennial flow in the 

Amargosa River, suggests that in future wetter climates, a larger amount of groundwater and 

surface flow would reach Alkali Flat than under the present-day climate. Today, Alkali Flat is 

mostly a flow-through system (Reynolds et al., 2007). The very low topographic gradient 

suggests that greater flow will not lead to extensive standing water, and that the area would 

remain an assemblage of variable extents of wet and dry playas in future climates. Additional 

flow in the river bed continues down to Death Valley, where potentially standing water 

(and during some periods, an extensive lake) remained year-around during wetter climates, 

based on paleorecords (e.g., paleo-Lake Manly; Paces and Whelan, 2012; Smith and 

Street-Perrott, 1983).

2.3.5 Summary of Surface Discharge Environments 

Surface discharge environments along the Yucca Mountain flow path fall into three generic 

types: (i) pumping for irrigation and other uses, as at Amargosa Farms; (ii) discharge at springs, 

such as at Furnace Creek or the paleo-State Line Deposits; and (iii) discharge at wet and dry 

playas and salt pans, such as at Alkali Flat or Middle Basin. These types encompass the range 

of discharge environments expected under current and future climate conditions. 

2.4 Groundwater Modeling 

In the 2008 SEIS, DOE provided a description of the two groundwater flow models of different 

scales that were used to quantify flow in and around the DVRFS. The small-scale model covers 

Yucca Mountain and southward to Amargosa Desert (the Yucca Mountain Site Scale model). 

This model remains unchanged since 2008 in DOE (2014a). The Yucca Mountain Site Scale 

model provides flow information for groundwater conditions near Yucca Mountain, which DOE 

used to support its evaluation of repository performance in its SAR (DOE, 2008b). The DVRFS 
2-29 

model is the larger scale model used by DOE in its SAR; it provides information about areas 

beyond those in the Yucca Mountain Site Scale model. As previously noted, the NRC staff has 

found DOE’s integration of the multiple models for saturated zone flow to be acceptable as part 

of the NRC’s safety evaluation (NRC, 2014a; Section 2.2.1.3.8). For its 2002 EIS and 2008 

SEIS analysis, DOE used the DVRFS model and its representation of groundwater flow beyond 

the postclosure compliance location and along the flow path to Death Valley. The 2008 SEIS 

describes the DVRFS model, as documented by the USGS in Belcher (2004). The USGS has 

since updated the documentation of the DVRFS model (Belcher and Sweetkind, 2010), but the 

information about the model in the updated report is substantively unchanged (Belcher and 

Sweetkind, 2010). 

DOE used a slight modification of the Belcher and Sweetkind (2010) model in its 2014 analyses 

(DOE, 2014a). DOE used the 2004 DVRFS model to calculate the groundwater conditions 

(e.g., water table position) present before extensive pumping in Amargosa Farms (nominally for 

conditions in 1913). The model input parameters were then adjusted to match the transient 

(changing) conditions that account for groundwater pumping from the period of 1913 to 1998 

(Belcher and Sweetkind, 2010). DOE (2014a) incorporated an expanded pumping data set from 

Moreo and Justet (2008) that accounted for the period 1913 to 2003, to further update the 

DVRFS model. As previously noted in Section 2.2.3, pumping records since 2003 indicate little 

change in the past decade, so this update and analysis capture current pumping rates 

(NDWR, 2015). This update and DOE’s observations from modeling several scenarios are 

described below, especially as they pertain to the affected environment beyond the postclosure 

compliance location. 

Effects of Pumping on Groundwater Conditions 

As described in Section 2.2.3 (Groundwater Pumping), substantial pumping in the area began in 

1913 and has increased markedly in the past several decades. Evaluation of groundwater 

conditions without pumping is an important starting point for comparisons with paleorecords for 

calibrations to account for transient conditions caused by pumping, and for analyzing the 

groundwater impacts if no pumping were to occur in the future. 

Estimates of pumping rates changed as the DVRFS model evolved from its early version 

(e.g., D’Agnese et al., 1999), to that used in the 2002 EIS, the 2008 SEIS, and in DOE (2014a). 

Pumping rates for irrigation, the primary use of groundwater in the Amargosa Farms area, are 

typically not directly measured. Model groundwater pumping, therefore, is from indirect 

estimates. Not only does irrigation usage vary from year to year, but techniques differ for 

estimating the pumping rates for irrigation (DOE, 2014a). The methods used by the USGS and 

the NDWR are both based on reliable data for the amount of land under irrigation, but use 

different water application rates (amount per acre) to generate estimates of pumping rates. 

Groundwater pumping estimates for the DVRFS in the 2002 EIS and the 2008 SEIS are 

different from those used by the USGS in developing its updated model (Belcher and 

Sweetkind, 2010). The 2002 EIS and 2008 SEIS used estimates from the State of Nevada, 

whereas Belcher and Sweetkind (2010) used estimates developed by the USGS that were 

slightly greater (by about 20–30 percent) than those of the State of Nevada. Use of greater 

pumping rates may lead to over-estimates of flow rates and potentiometric elevations 

(e.g., water table for unconfined aquifers) in the absence of pumping. 

The Belcher (2004) model was first calibrated to account for steady-state groundwater levels 

prior to 1913, before significant pumping occurred in the area of the DVRFS. This no-pumping 

condition provides an estimate of the water table position and flow path directions in the 
2-30 

Amargosa Farms area without the water table decrease caused by pumping. The model was 

then calibrated for transient conditions using values for water level, spring flows, 

evapotranspiration, and pumping as they changed over time from 1913 to 1998 (DOE, 2014a). 

The results of these calibrations were compared with measured water table positions as they 

changed until 1998. 

Uncertainties in future pumping rates were considered in DOE (2014a), especially concerning 

the effect on the water level in Devils Hole and on the positive vertical gradient from the regional 

carbonate aquifer to the overlying alluvial aquifer in the Amargosa Farms area. Using the 

USGS DVRFS model, DOE conducted simulations of long-term pumping, up to 500 years, at 

the 2003 groundwater pumping rates. These simulations were done both with and without an 

additional 10,600 acre-ft/yr [13.1 million m3

/yr] of withdrawal from the lower carbonate and 

alluvial aquifers in Tikapoo and Three Lakes Valleys, as proposed by the Southern Nevada 

Water Authority for additional supply wells east of the NNSS (SNL, 2009). The modeling results 

suggested that the upward hydraulic gradient in the lower carbonate aquifer would be 

maintained after 500 years of additional pumping and would be within 3 percent of that 

predicted for no-pumping steady-state conditions. Simulation results with the additional annual 

withdrawal quantity proposed by the SNWA indicated little additional impact on water levels 

beyond that calculated without the SNWA-proposed withdrawal (SNL, 2009). In any case, 

continued heavy pumping from the shallow alluvial aquifers would result in an increase in the 

upward vertical gradient of the lower carbonate aquifer in the Amargosa Desert (SNL, 2009), at 

least until the pumping rate triggered the restrictions discussed in Section 2.2.3 regarding 

impacts on the water levels at Devils Hole. 

Potential impacts from other basin withdrawals in eastern Nevada proposed by the SNWA, 

besides those from the Tikapoo and Three Lakes Valleys, are not considered in this 

supplement. This is because permits have not been issued for such withdrawals, the 

groundwater withdrawal amounts are highly speculative, and, according to SNWA, such projects 

would only be pursued when needed to supply future demands (SNWA, 2015). The NRC staff 

did consider the proposed project that includes Delamar, Dry Lake, Cave, and Spring Valleys, 

for which an application for water rights has been submitted, but the permit is the subject of 

litigation (SNWA, 2015). A Bureau of Land Management (BLM) Final EIS has been completed 

for this project, which includes modeling results indicating no significant impact to groundwater 

conditions in Amargosa Farms or along the groundwater path to Death Valley (BLM, 2012c). 

The NRC staff has reviewed the BLM report, and agrees with its conclusion based upon the 

geologic separation of the hydrologic basins. 

For the analyses of impacts in this supplement, the NRC staff used results based on the 

updated DVRFS model (Belcher and Sweetkind, 2010; DOE, 2014a), which included expanded 

pumping data for 1913 to 2003. Consistent with its previous evaluation of saturated zone flow in 

the area (NRC, 2014a, Section 2.2.1.3.8), the NRC staff has concluded that the updated 

DVRFS model is a reasonable representation of the regional groundwater system. Values of 

groundwater flow velocity derived from the updated DVRFS model were used as inputs to 

groundwater transport calculations (DOE, 2014a). The NRC staff used the result of these 

calculations to determine the potential impacts when groundwater pumping is assumed to occur 

(Section 3.3.1) and when no pumping is assumed to occur (Section 3.3.3). 

Effects of Climate on Future Flow Paths 

D’Agnese et al. (1999) simulated the future groundwater environment by using increased 

recharge to reflect expected future climate conditions and assessing the impact on groundwater 
2-31 

conditions. The different distribution and increased values of recharge were intended to reflect 

cooler and wetter conditions comparable to the glacial climate of 21,000 years ago. The model 

used by D’Agnese et al. (1999) was a predecessor to the current version of the DVRFS model 

(Belcher and Sweetkind, 2010), but the models are sufficiently alike to expect similar 

conclusions for the effect of climate change. D’Agnese et al. (1999) found that the elevated 

water table calculated for the cooler/wetter climate had generally the same shape as the present 

day water table. This means that the directions of flow along the path from Yucca Mountain 

would not likely differ between present-day conditions and a future cooler/wetter climate. This 

analysis also found that the extent of water table rise for this cooler/wetter climate was 

consistent with the observed locations of paleodischarge deposits. The D’Agnese et al. (1999) 

model predicted that the confluence of Fortymile Wash and the Amargosa River would be a 

discharge location under future wetter conditions, consistent with discharge at the State Line 

Deposits area. Furthermore, the model results suggested that long stretches of both channels 

would become perennial streams. D’Agnese et al. (1999) noted that flow in the rivers, along 

with the increased discharge of groundwater, in a cooler/wetter climate state would be sufficient 

to supply the water in paleo-Lake Manly in Death Valley. 

2.5 Water Use and Quality 

This section provides a brief description of water use and quality for areas south of 

Amargosa Farms, along the flow path to Death Valley.

In the 2002 EIS and 2008 SEIS, DOE provided a description of water use and the biosphere for 

the Yucca Mountain area and south to the postclosure compliance location, approximately 

18 km [11 mi] along the flow path. Beyond the postclosure compliance location, water from 

wells or springs is used in Amargosa Farms, and Furnace Creek. Amargosa Farms and 

Furnace Creek are along the primary flow path for groundwater from Yucca Mountain. The 

2002 EIS and 2008 SEIS list water uses in the Amargosa Valley as irrigation, mining (mostly in 

western Amargosa Valley), livestock, and for quasi-municipal, commercial, or domestic water 

supply. DOE (2014a) states that water from the Furnace Creek springs (Texas, Travertine, and 

Nevares) is used to support Death Valley National Park and the Timbisha Shoshone Tribe, 

which occupies several hundred acres within Death Valley National Park. The springs support 

the commercial and domestic water supplies, including a small commercial date farm. 

The 2002 EIS and 2008 SEIS provide descriptions of regional groundwater quality, including for 

the area of pumping in Amargosa Farms. Generally, the quality of the groundwater in 

Amargosa Farms is good, and the tested groundwater sources met the EPA’s primary 

drinking-water standards (DOE, 2014a; 2008a). Some groundwater samples from the 

Amargosa Farms area contained concentrations of naturally occurring arsenic above EPA 

primary drinking water standards; as noted in DOE (2014a), these samples were not collected 

from drinking water systems, so the EPA standards are not directly applicable. Water from 

Texas Spring at Furnace Creek (again, not collected from a drinking water system) had similar 

high arsenic levels, and also had naturally occurring lead and fluoride concentrations above 

drinking-water standards (DOE, 2014a). Concentrations of selected groundwater constituents 

are given in Table 2-2, for potential contaminants released from the proposed repository. 

The quality of water discharged to playas, either as intermittent seeps, standing water, or runoff, 

is variable but is often highly saline. Because of the low amount of water, lack of reliability, and 

poor quality of this water, it is not of practical use by humans and has not been developed 

for use. 
2-32 

2.6 Analysis Cases for Assessing Impacts 

Any potential changes in the affected groundwater environment would be due to changes to the 

regional and local groundwater system that affect flow paths, amount of flow, or discharge 

locations. As discussed above, changes to the groundwater system over the one-million-year 

period depend primarily on two factors that will likely vary in the future: climate state (through 

changes in the amount of groundwater recharge and losses through evapotranspiration) and the 

amount of regional pumping (through the lowering of the water table and possible capture of 

contaminants). To address these two factors, two analysis cases are considered that provide a 

reasonable range of conditions to assess the affected environment and potential impacts. 

 Analysis Case 1: Pumping in Amargosa Farms for current uses at current rates 

 Analysis Case 2: Natural surface discharge at and downstream from Amargosa Farms 

with limited or no pumping in Amargosa Farms 

The analysis cases address both pumping in the Amargosa Farms area (substantial removal of 

groundwater from the system) and no pumping, and thus account for uncertainty in future 

pumping levels. Analysis Case 1 considers present-day rates of pumping in Amargosa Farms. 

At present-day extraction rates, all the contaminant releases from a repository at 

Yucca Mountain are assumed to be captured by the pumping wells (see Figure 2-5), consistent 

with the analysis assumption for water extraction at the postclosure compliance location 

(DOE, 2008b; NRC, 2014a). 

Analysis Case 2 accounts for surface discharges beyond the postclosure compliance location in 

the case of limited or no pumping in Amargosa Farms. In this case, contaminants could reach 

locations further along the flow path, as far as Death Valley. With little or no pumping in 

Amargosa Farms, contaminants from a repository could discharge to the surface at areas 

similar to the State Line Deposits or Alkali Flat, or to Furnace Creek springs and Middle Basin in 

Death Valley (see Figure 2-5). 

As discussed in Section 2.3.2, paleodischarge sites from water flowing beneath Yucca Mountain 

have not been identified along the flow path upgradient from Amargosa Farms. Although the 

future flow path is subject to some uncertainty, analyses suggest that it would not change 

appreciably (Section 2.4). For this reason, natural discharge of contaminated water is not 

Table 2-2. Concentrations of Naturally-Occurring Constituents in Groundwater From 

Amargosa Farms and Furnace Creek Springs, for Potential Contaminants 

Contributing to Impacts Discussed in Chapter 3. 

Constituent Groundwater 

Amargosa Farms 

Discharges from 

Furnace Creek 

Springs 

Federal Drinking 

Water Standard 

(40 CFR 141) 

Total Uranium (μg/L) 2.55 5.1 30 

Molybdenum (mg/L) 0.007 (0.03) None 

Vanadium (mg/L) (0.01) (0.01) None 

Nickel (mg/L) — — None 

Data from highest value given in DOE, 2008a, Table 3-19, or DOE, 2014a, Table 2-2. Parentheses indicate 

concentration below detection; value in parentheses is detection limit. 
2-33 

expected between Yucca Mountain and Amargosa Farms, even under future cooler and wetter 

climates, thus possible impacts from natural discharge are not considered for that area. 

Therefore, these analysis cases reasonably capture the credible range of future conditions, 

encompassing future climate change and potential changes in groundwater extraction in 

Amargosa Farms. Two important factors related to future pumping rates further support this 

conclusion. The first is the restriction on groundwater pumping due to basin withdrawal related 

to impacts on water levels at Devils Hole (Section 2.2.3). Because of this restriction, the 

pumping rate is not likely to be greater than that over the past several decades, and may be 

less in the future. The second factor is that in a future cooler/wetter climate, the demand for 

groundwater for irrigation could lessen and pumping could decrease. In such a climate of lower 

evaporation and increased precipitation, less irrigation would be required to support present-day 

farming. If pumping decreases substantially, groundwater withdrawal may not capture all of the 

contaminants from a repository. In this case, potential impacts could occur at downstream 

discharge locations. These are addressed in Analysis Case 2, which assumes most 

contaminants reach discharge locations downstream of Amargosa Farms. 

Thus, potential impacts at Amargosa Farms under the present climate and pumping rates, or a 

cooler/wetter climate and somewhat reduced pumping rates, are addressed by Analysis Case 1 

(which assumes all contaminants are captured at Amargosa Farms). Potential impacts 

downstream of Amargosa Farms under both climate states with limited or no pumping are 

addressed by Analysis Case 2. The impacts for these two analysis cases are discussed in 

Chapter 3. 

3-1 

3 ENVIRONMENTAL IMPACTS 

The affected environment described in Chapter 2 includes the aquifer and the surface discharge 

sites beyond the postclosure compliance location at approximately 18 km [11 mi] along the 

groundwater flow path from Yucca Mountain. This chapter assesses the potential impacts for 

these environments from contaminants released from the proposed repository. 

In Chapter 5 of its Final Environmental Impact Statement (EIS) (DOE, 2002), the 

U.S. Department of Energy (DOE) described its approach and analyses for estimating potential 

impacts on human health, other biological impacts, and environmental impacts from releases of 

radioactive and nonradioactive materials to the environment after closure of the proposed 

repository at Yucca Mountain. Using a similar approach and analysis for its 2008 Supplemental 

Environmental Impact Statement (SEIS) (DOE, 2008a), DOE summarized, incorporated by 

reference, and updated information presented in Chapter 5 of the 2002 EIS. In the 2002 EIS 

and 2008 SEIS, DOE described the affected environment and impacts up to the postclosure 

compliance location at approximately 18-km [11-mi] distance along the flow path from the 

repository. At the postclosure compliance location, the impacts were estimated for the 

reasonably maximally exposed individual (RMEI), consistent with the RMEI characteristics in 

10 CFR Part 63. In its 2008 SEIS, DOE stated that the environmental impacts beyond the 

postclosure compliance location would be less than those at the postclosure compliance 

location. In its Adoption Determination Report (ADR) (NRC, 2008a), the NRC staff determined 

that it could adopt the general approach used by DOE in estimating releases from the repository 

and the impacts at the postclosure compliance location, but concluded that the affected 

environment and any impacts for areas beyond the postclosure compliance location were not 

adequately described in the 2002 EIS and 2008 SEIS for potential releases of radiological and 

nonradiological contaminants from the repository. 

In this NRC staff-prepared supplement, impacts on water and soil, ecology, cultural resources, 

and environmental justice are provided for locations beyond the postclosure compliance 

location, drawing on the previous work by DOE and its subsequent analyses in DOE (2014a). 

The affected environment is described in Chapter 2, including potential locations for 

groundwater pumping and types of natural surface discharge in the Yucca Mountain 

groundwater flow path beyond the postclosure compliance location, downstream to 

Death Valley. 

The description of water and soil impacts is in Section 3.1, ecological impacts in Section 3.2, 

cultural resources in Section 3.3, and environmental justice in Section 3.4. A summary of 

impacts is provided in Section 3.5. 

3.1 Impacts on the Aquifer, Water and Soil 

In the 2002 EIS and 2008 SEIS, DOE provided radiological impacts for the RMEI at the 

postclosure compliance location (also called the RMEI location) for the 10,000-year and 

one million-year periods following repository closure for a stylized scenario of groundwater 

pumping for irrigation of limited local food cultivation. The scenarios analyzed by DOE follow 

the characteristics of the RMEI in 10 CFR 63.312. 

DOE’s analysis of radiological impacts for the RMEI in its 2002 EIS and 2008 SEIS is based on 

results from its Total System Performance Assessment (TSPA) model for performance of the 

repository after permanent closure (DOE, 2008b, Chapter 2). The development of the model 

involved a systematic assessment of potential features, events, and processes that could affect 
3-2 

the release of radioactive material from the repository, transport of that material beyond the site 

boundary, and radiological exposure to the RMEI. The postclosure compliance location is 

defined in 10 CFR 63.312 as the point where the RMEI would receive the greatest dose. Doses 

beyond this location along the groundwater flow path are lower due to dispersion and sorption of 

contaminants in the aquifer, along with radioactive decay during longer transport times. The 

NRC staff found DOE’s TSPA methodology to be acceptable as part of its safety evaluation 

(NRC, 2014a, Section 2.2.1.4.1). 

In the 2002 EIS, but not in the 2008 SEIS, DOE scaled results from the postclosure compliance 

location to account for dispersion in the groundwater system to estimate impacts 30 and 60 km 

[19 and 37 mi] downstream from the repository. These distances from Yucca Mountain 

approximate the distances to Amargosa Farms and to Alkali Flat, respectively. In the 2002 EIS 

and 2008 SEIS, DOE provided chemical toxicity impacts in terms of a bounding analysis at the 

RMEI location only for the first 10,000 years after repository closure. 

This supplement provides updated impact information for groundwater pumping in the 

Amargosa Farms area, and provides impacts at sites of natural surface discharge along the flow 

path between the postclosure compliance location and Death Valley along the Yucca Mountain 

groundwater flow path. The impacts include those from both radiological and nonradiological 

contaminants at pumping locations (Amargosa Farms) and at natural discharge locations for 

one million years; results at earlier times are also provided. Impacts from groundwater 

contamination prior to this timeframe are not expected, as described in the NRC’s Safety 

Evaluation Report (SER) and in DOE’s EISs (DOE, 2008a, 2002; NRC, 2014a). 

As discussed in Chapter 2, impacts are analyzed accounting for uncertainty in both future 

pumping rates and climate using two analysis cases. Consideration of the type of discharge site 

(pumping from wells or natural surface discharge), uncertainties in future pumping rates in 

Amargosa Farms, and potential future climate states leads to delineation of two cases for the 

analysis of impacts. These cases encompass the reasonable range of future conditions and 

activities. These analysis cases are as follows: 

Analysis Case 1: Pumping at Amargosa Farms 

— Present-day and future cooler and wetter climate states 

Analysis Case 2: Surface Discharge Downstream of Amargosa Farms 

— Assumes limited or no pumping in Amargosa Farms 

— Present-day and future cooler and wetter climate states 

The first analysis case assumes that the pumping rate and well distribution in Amargosa Farms 

is comparable to the present-day and is sufficient to extract any contaminants released from the 

repository to the groundwater system. It also assumes that the present-day pumping rates will 

continue into the future. Both present-day climate and a future cooler/wetter climate are 

considered in the pumping scenario of Analysis Case 1 (Section 3.1.1). The second analysis 

case assumes that limited or no pumping occurs in Amargosa Farms and, thus, all 

contaminants would migrate to natural discharge locations along the path from Amargosa 

Desert to Death Valley (Section 3.1.2). Downstream natural surface discharge locations 

considered in Analysis Case 2 include natural spring discharges in the State Line 

Deposits/Franklin Well area, Furnace Creek, and the playa/salt pan of Middle Basin of 
3-3 

Death Valley. An additional potential flow path to surface discharge to a playa/salt pan 

environment at Alkali Flat is also considered (see Section 2.3.3). Analysis Case 2 also 

addresses both present-day and future cooler/wetter climates. The methods used in this 

analysis are summarized in the next section, and described in more detail in Appendix A. 

Considering the uncertainty in future pumping projections, it is likely that future conditions would 

lie somewhere between the two analysis cases. Thus, these two analysis cases are not 

additive. They represent, instead, the endpoints of the spectrum of future scenarios addressing 

the uncertainty of pumping in Amargosa Farms. Possible future scenarios could fall at (in an 

extreme case) or between these endpoints. For example, some reduced amount of pumping in 

Amargosa Farms would extract some fraction of a contaminant plume, and the remainder would 

be transported down the flow path. In this case, the impacts at Amargosa Farms would be less 

than those described in Analysis Case 1, and the impacts downstream would be less than those 

described in Analysis Case 2. As discussed below, the magnitude of the environmental impacts 

in a given setting is generally proportional to the amount of contaminants present in that setting. 

Uncertainty in climate is addressed by determining the peak impact from either the present-day 

or a future cooler/wetter climate for each impacted environment. 

The next three sections summarize the methods used in analyzing impacts, the mass balance 

approach for contaminants in the aquifer, and information on typical human radiation exposure 

from all sources, as well as applicable regulatory standards for radiation and other potential 

contaminants. The subsequent sections then describe the results for each of the two 

Analysis Cases. 

Analysis Method 

The impact analysis in this supplement builds off the DOE results for the postclosure 

compliance location (DOE, 2008a; 2002), which the NRC staff found acceptable in its ADR 

(NRC, 2008a), as well as DOE’s assessment of overall repository performance (DOE, 2008b; 

NRC, 2014a). From this basis, an analytical solution is then used to calculate the transport of 

radiological and nonradiological material beyond the postclosure compliance location to affected 

environments along the groundwater flow path to Death Valley. This analytical solution is part 

of an analysis framework that includes source term development, transport, and impact 

calculations. This framework is described in detail in Appendix A, which includes descriptions of 

(i) source terms (i.e., calculated releases from the repository) for radiological and 

nonradiological contaminants, (ii) models of contaminant transport from the repository to the 

postclosure compliance location, (iii) models of contaminant transport beyond the postclosure 

compliance location along the flow path to discharge locations, and (iv) processes that may 

occur at discharge locations that may affect concentrations and exposures at different types of 

affected environments. 

The results of these calculations and impacts at each location for the analysis cases are 

provided in tables and plots in the following sections for 10,000 and one million years following 

repository closure. In some cases, the greatest (peak) concentration values for contaminants at 

a given location do not occur exactly at the 10,000- or one-million-year times, due to the pattern 

of the releases from the repository over time and the effects of sorption during transport. This is 

particularly apparent for some of the nonradiological contaminants (e.g., nickel), where 

conservative assumptions in the model for release from the repository and significant sorption 

during transport strongly affect the peak values (see Figure A–1 and Appendix A for further 

details). Therefore, the “Peak Value” tables in this chapter give the highest calculated values for 

the initial 10,000-year period and the 10,000-to-one million-year period under the different 
3-4 

model conditions (in cases where the greatest value occurs after 10,000 years, the value at 

10,000 years is given in the “10,000 years” column). In addition, specific times of peak 

contaminant concentrations at each location are discussed in the following sections. In all 

tables, very small values (less than 10−9) have been rounded to zero. 

Mass Balance Description 

The NRC staff concluded in the ADR (NRC, 2008a) that a description was needed of the 

accumulated amounts of radiological and nonradiological contaminants from the repository that 

may enter the groundwater over time, as well as a description of where those contaminants 

would travel along the flow path. 

Sections 3.1.1 and 3.1.2 of this chapter consider impacts to groundwater and surface discharge 

using mass flux (the amount of a contaminant moving through the system), accumulation, 

exposure pathways, and dose. As part of the impacts described in these sections, the amount 

of radiological and nonradiological material from the repository is estimated that will 

(i) discharge to the surface at specific locations and accumulate in soils and (ii) reside in the 

aquifer environment (dissolved in water and sorbed to rock) between those locations. In 

Sections 3.1.1 and 3.1.2, subsections for Aquifer Environment and Soils include descriptions of 

where contamination may occur along the path between the postclosure compliance location 

and Death Valley for present-day and wetter climates for two time frames: 10,000 and 

one million years. 

Impacts of Calculated Contaminant Levels 

This section provides context for the 

calculated radiological and 

nonradiological concentrations, 

radiological dose, and nonradiological 

body intake used to determine the 

level of impact from releases at 

Yucca Mountain to different areas of 

the affected environment. 

On average, Americans receive a 

radiation dose of approximately 

620 mrem/yr [6.2 mSv/yr] 

(NRC, 2015c). Half {310 mrem/yr 

[3.1 mSv/yr]} comes from man-made 

sources of radiation, including 

medical, commercial, and industrial 

sources. The other half of this dose 

comes from natural background 

radiation, which is predominantly due 

to exposure to radon in air.1

 In general, a yearly dose of 620 mrem [6.2 mSv] has not been 

shown to cause humans any harm (NRC, 2015c). The natural background radiation, excluding 

 

1

Radon exposure varies depending on several factors, including geographic location, housing type, ventilation, and 

local geology. On average in the U.S., radon exposure accounts for a dose of approximately 200 mrem/yr 

[2.0 mSv/yr] (NRC, 2015c). 

Radiation Exposure and Cancer Risk 

Public health data do not absolutely establish the occurrence of 

cancer following exposure to low doses and dose rates of 

radiation below about 10,000 mrem [100 mSv]. Studies of 

occupational workers who are chronically exposed to low levels 

of radiation above normal background have shown no adverse 

biological effects. Even so, the radiation protection community 

conservatively assumes that any amount of radiation may pose 

some risk for causing cancer and hereditary effect, and that the 

risk is higher for higher radiation exposures. The linear nothreshold (LNT) dose-response relationship is used to describe 

the relationship between radiation dose and the occurrence of 

cancer. This dose-response model suggests that any increase 

in dose, no matter how small, results in an incremental 

increase in risk. The NRC accepts the LNT hypothesis as a 

conservative model for estimating radiation risk. 
3-5 

radon, for a resident of Amargosa Valley is 96 mrem/yr [0.96 mSv/yr] (DOE 2002, Table 3-30). 

For this supplement, a total natural background radiation exposure at Amargosa Farms of 

approximately 300 mrem/yr [3.0 mSv/yr] (including radon) is used as a comparison to the 

estimated doses for populations at affected environments along the flow path from 

Amargosa Farms to Death Valley. 

Further context for the dose values provided in this supplement is the average annual dose 

estimated for the postclosure compliance location from the 2008 SEIS. DOE calculated 

maximum average annual dose for the RMEI at the postclosure compliance location to be 

0.24 mrem/yr [0.0024 mSv/yr] for the initial 10,000 years after repository closure, and the 

maximum average annual dose one million years after closure to be 2.0 mrem/yr [0.02 mSv/yr] 

(DOE, 2008a, Section 2.4.1). The NRC staff has found DOE’s calculations to be acceptable 

as part of its safety evaluation (NRC, 2014a, Section 2.2.1.4.1). The regulatory safety 

standards in 40 CFR Part 197 and 10 CFR Part 63 for the RMEI are 15 and 100 mrem/yr 

[0.15 and 1.0 mSv/yr] for the 10,000 and one million year periods, respectively. 

One way to understand the impact of radiological dose is in terms of a risk of causing cancer or 

a severe hereditary effect. This can be done through a conversion factor, which assumes a 

simple linear relationship between the dose and the risk of these health effects. Using the 

conversion factor for members of the public recommended by the International Committee on 

Radiological Protection (ICRP) (ICRP, 2007), the probability of a latent cancer fatality, nonfatal 

cancer, or severe hereditary effect from a 1.0 mrem/yr [0.01 mSv/yr] dose is 5.7 × 10−7

, or less 

than one in one million. 

For nonradiological chemical contaminants, impacts to human health are compared to the 

U.S. Environmental Protection Agency (EPA) Oral Reference Dose (EPA, 1999a,b; 1997a,b; 

1994), which is the chemical level below which no 

detectable human health effects would occur. In this 

supplement, uranium (U) is evaluated for both 

radiological and nonradiological contaminants, 

because in addition to being radioactive, it has a 

notable toxicity as a heavy metal. For 

nonradiological analysis, U concentrations are given 

as a sum of the U isotopes from the radionuclide 

calculations, since the chemical risk of U does not 

depend on the particular isotope. 

Additional comparisons provide context on the 

quantities and concentrations of potential repository 

contaminants that may be present in groundwater or 

discharge to the surface and accumulate in soil. Calculated concentrations of nonradiological 

materials in water and soils are compared to natural background levels from water and soil 

analyses, where available. Reference values for soil concentration impacts are the soil 

screening levels used in determining the need for further evaluation or remediation during 

cleanup of contaminated land. The EPA has established generic soil screening levels for many 

chemicals, including nickel (Ni), molybdenum (Mo), vanadium (V) and U (EPA, 2015). These 

screening levels are not cleanup standards, but are used a guidelines for determining the need 

for further action. The screening levels for specific contaminants are included in the subsequent 

sections, as appropriate. 

EPA Oral Reference Dose 

The Oral Reference Dose is an estimate of 

a daily oral exposure of a chemical to the 

human population (including sensitive 

subgroups) that is likely to be without an 

appreciable risk of deleterious effects 

during a lifetime. In the U.S., the EPA 

establishes the Oral Reference Dose after 

a thorough review of the health effects 

data for individual chemicals. 
3-6 

3.1.1 Analysis Case 1: Pumping at Amargosa Farms 

In the 2002 EIS and 2008 SEIS, DOE provided estimates of impacts for the RMEI at the 

postclosure compliance location. In its ADR, the NRC staff found this impact assessment for 

the RMEI location to be acceptable for adoption (NRC, 2008a). In this supplement, impacts are 

estimated at the nearest population center to the repository location, Amargosa Farms, which is 

approximately 17 km [11 mi] beyond the postclosure compliance location, or approximately 

35 km [22 mi] along the flow path from Yucca Mountain. This distance is representative of 

the primary irrigation and farming areas in Amargosa Farms, which range from 14 to 20 km 

[9 to 12 mi] from the postclosure compliance location. There are residents and businesses 

between the primary farming areas and the postclosure compliance location. Most of the wells 

supplying water to residents and businesses are close to the farming area. There is an isolated 

set of several wells just south of the junction of Highways 95 and 373, which is consistent with 

the DOE determination that that there were no permanent residents closer than 22 km [13.7 mi], 

from the postclosure compliance location, as described in Section 2.1.1 of this supplement. In 

its evaluation of impacts on these residential and business wells, the NRC staff conservatively 

adopts the analysis in DOE (2008a) for the RMEI. This is because the same dose pathways 

used for the impacts at Amargosa Farms in this supplement are those identified by DOE in its 

EISs for the RMEI. These are appropriate because the dose pathways for the RMEI were 

based on activities and lifestyles of residents in Amargosa Farms. Amargosa Farms is a 

community that uses groundwater pumping for irrigation and for its commercial and domestic 

water supply. The dose pathways for a resident of Amargosa Farms are external (body) 

exposure, inhalation, and ingestion of crops, meat, and soil. Details of these pathways are 

described in Appendix A and in DOE (2014a, Table B-2). 

Impacts in this section are described in terms of (i) the amount of contaminants from the 

repository in the groundwater system between the postclosure compliance location and 

Amargosa Farms, (ii) the concentration of contaminants in the groundwater at the 

Amargosa Farms area, (iii) the concentration of contaminants in soils at the Amargosa Farms 

area due to irrigation, and (iv) the radiological dose and body intake of contaminants for the 

identified exposure pathways. Together, these items provide a description of the distribution of 

contaminants present in the aquifer and the impact of radiological and nonradiological 

contaminants on the affected environment. This section addresses the impacts under both the 

present day and the cooler/wetter climate states. 

The transport model uses a path length of 17 km [11 mi; the distance from the RMEI location to 

Amargosa Farms] and transport properties that are distance-weighted from each segment of the 

pathway (see Appendix A, Section A.1.2). Transport segments are the different hydrogeological 

model units in the Death Valley Regional Flow System (DVRFS) model that predict the 

groundwater flow from Yucca Mountain along the path from the postclosure compliance location 

to (in this case) Amargosa Farms. For items (ii) to (iv) in the previous paragraph, several other 

parameter values are required: 

 The mass flux of radiological and nonradiological material from the repository 

reaching wells at Amargosa Farms is calculated using the 2003 pumping rate of 

16,828 acre-feet/year [20.7 million m3

/year] taken from Moreo and Justet (2008). This 

pumping rate is more than five times larger than the value used in the 2008 SEIS for the 

RMEI, which calculated contaminant concentrations based on a withdrawal rate of 

3,000 acre-feet/year [3.7 million m3

/year]. 
3-7 

 Transport in the aquifer to Amargosa Farms is calculated using a value of 

0.00613 m/day [0.020 ft/day] for the specific discharge (flow rate) along the 17 km 

[11 mi] path in the present-day climate (see Appendix A, Section A.1.2). For the wetter 

climate, the specific discharge is multiplied by a factor of 3.9 (DOE, 2014a; 2008b, 

Section 2.3.9). An average porosity in the aquifer of 0.16 is used for both climate states. 

 Contaminated water extracted by pumping can be recycled into the aquifer through 

irrigation and other uses, as water pumped to the surface can infiltrate, reach the water 

table, and be pumped again (see Appendix A, Section A.2.1 for details of the irrigation 

recycling model). The analysis in this supplement uses a value of 86 percent for the 

recycling fraction (the amount of water pumped to the surface that reaches the water 

table), and a value of 100 percent for the recapture fraction (the fraction of that water 

which is then captured by pumping and returned to the surface). These values are 

conservative in that they assume that contaminants are brought to the affected 

environment with high efficiency. These values result in an overall factor of 0.86 for 

contaminant recycling through well pumping for Amargosa Farms, compared to the 

value of 0.11 for the RMEI at the compliance location in previous recycling analyses 

(DOE, 2014a; Kalinina and Arnold, 2013; SNL, 2007b). A larger value for this factor 

leads to greater calculated contaminant concentrations in the exposure pathways, 

greater estimates of dose and body intake, and greater calculated values of 

contaminants accumulating in soils. 

 Dose conversion factors used in this analysis are derived from DOE (2008b, 

Table 2.3.10-12) with adjustments for potential secular disequilibrium of decay chain 

radionuclides (see Appendix A, Section A.1.2). The NRC staff has found these dose 

conversion factors to be acceptable as part of its safety evaluation (NRC, 2014a, 

Section 2.2.1.3.14) 

All radiological and nonradiological contaminants in the releases from the repository 

(which becomes the source term for this evaluation) are analyzed in the transport and 

accumulation models. Only those radionuclides that (i) reach the affected environment, beyond 

the postclosure compliance location and to the Amargosa Farms area, and (ii) are major 

contributors to the calculated dose, are described in the sections that follow. Calculated 

concentrations of other radionuclides are extremely low and do not contribute to estimates of 

dose or other environmental impacts. For Analysis Case 1 (Pumping in Amargosa Farms), the 

radionuclides that are significant contributors to dose at Amargosa Farms area are technetium 

(Tc)-99, iodine (I)-129, selenium (Se)-79, uranium (U)-233, thorium (Th)-230, neptunium 

(Np)-237, and uranium (U)-234 for both the present-day and wetter climates, in their 

approximate order of significance. The relative significance of radionuclides varies with time 

due to the timing of release from the repository and due to sorption, decay, and radionuclide 

ingrowth during transport. Nonsorbing species (e.g., Tc and I) are not delayed during transport 

and reach the affected environment faster than sorbing species (such as U or Th). All four of 

the nonradiological chemical species in the source term from the repository (Mo, Ni, V, and U) 

reach the Amargosa Farms area. 

Aquifer Environment 

This section describes the total amount of contaminants from the repository in the aquifer 

environment between the postclosure compliance location and the Amargosa Farms area. This 

amount changes over time, as contaminants are released from the repository and are 

transported by water to the aquifer and then downstream along the flow path. The 
3-8 

concentration of these contaminants in the groundwater at Amargosa Farms is then calculated 

from the amount of contaminants present in the groundwater, and the volume of water affected 

by the pumping. The amount of contaminants in the aquifer, and the contaminant concentration 

in the groundwater, represent the impacts on the aquifer. 

The term “aquifer environment” includes both the subsurface rock (porous media, predominantly 

alluvial sediments) and water within the pores of the rock, and is used here to include the 

contaminants both dissolved in the water and sorbed onto the rock. The amount of the 

contaminants in the aquifer environment between the postclosure compliance location and the 

Amargosa Farms area, based on mass balance calculations, is provided in Table 3-1a. The 

values in Table 3-1a result from calculating the difference between the mass of the 

contaminants that reach the postclosure compliance location and the contaminants that 

accumulate in the Amargosa Farms area. These values were calculated from the releases from 

the repository over time, the amounts transported downstream, and the amounts retained within 

the aquifer by sorption on rock surfaces. The mass flux released from the repository that 

reaches the postclosure compliance location was obtained from the DOE’s TSPA results 

(DOE, 2014a), The NRC staff has found DOE’s TSPA methodology to be acceptable as part of 

its safety evaluation (NRC, 2014a, Section 2.2.1.4.1). For U and Th, a combined value is 

reported that includes all the identified isotopes in the source term and daughter products. The 

mass of contaminants includes the effects of radioactive decay over time. 

These results show how different contaminants behave in the aquifer environment. At a given 

time, the nonsorbing species Tc-99, I-129, and Mo show much greater accumulation at 

Amargosa Farms (Table 3-1b) than in the aquifer environment between the postclosure 

compliance location and Amargosa Farms (Table 3-1a). This is because these species migrate 

more readily than sorbing species, and are not retained in the aquifer (except as dissolved in 

the groundwater). In contrast, sorbing species such as U, Th, Np, Ni, and V are present in the 

aquifer both sorbed onto the rock surfaces and dissolved in the groundwater. 

They therefore accumulate in the aquifer environment between the postclosure compliance 

location and Amargosa Farms. At 10,000 years after permanent closure, these sorbing species 

are present in the aquifer upstream from Amargosa Farms, but have a very small (or no) 

presence at Amargosa Farms (Table 3-1b), as they are held back on the rock surfaces within 

the aquifer. Over the one million year period, these species reach Amargosa Farms in greater 

abundance, but still show appreciable accumulation within the aquifer. 

The amounts of the six predominant radionuclides listed in Table 3-1a (by activity, in Curies) 

and nonradiological material (by mass, in grams) are used to calculate the average 

concentration of each contaminant in the aquifer environment between the postclosure 

compliance location and Amargosa Farms. This calculation requires an estimate of the volume 

occupied by the contaminant plume. These geometric assumptions give an affected aquifer 

volume of 5.1 km3 [1.2 mi3

]. For an average porosity of 0.16 (DOE, 2014a), this volume 

contains 0.82 km3

 [0.2 mi3] of water. Appendix A provides more detail on this calculation and 

its inputs. 

As noted above, the average concentration of a contaminant in the aquifer includes both the 

contaminants in the groundwater and those sorbed onto the rock surface. For a sorbing 

species, only some fraction of the contaminant will be dissolved in the groundwater. The 

groundwater concentrations are calculated using the amounts in the groundwater (not sorbed to 

the rock), and the appropriate volume of water (see Appendix A, Section A.2.1). 
3-9 

Table 3-2 provides concentrations of radiological and nonradiological material calculated for the 

groundwater in the vicinity of Amargosa Farms. The concentrations are calculated by dividing 

the mass flux to the Amargosa Farms area by the pumping rate from all wells in the area. 

Consistent with their behavior in the overall repository performance assessment, Tc-99 and 

I-129 are present in relatively higher quantities than other radiological contaminants because of 

their transport characteristics (i.e., they do not sorb). The amount of U reflects its high 

abundance in the repository waste inventory. As shown in Table 3-2, a cooler/wetter climate 

has variable effects on the calculated groundwater concentrations at Amargosa Valley. For 

Table 3-1a. Amount of Selected Radiological and Nonradiological Material From the 

Repository in the Aquifer Environment Between the Postclosure 

Compliance Location and Amargosa Farms. [1 kg = 2.2 lbs] 

Present-Day Climate Cooler/Wetter Climate 

10,000 years 1 million years 10,000 years 1 million years 

U isotopes (Ci) 1.5 290 1.5 81 

Th isotopes (Ci) 0.18 160 0.18 46 

Np-237 (Ci) 1.4 140 1.4 38 

I-129 (Ci) 3.2 × 10-4 0.18 3.4 × 10−5 0.018 

Tc-99 (Ci) 5.1 95 1.3 23 

Se-79 (Ci) 5.8 75 5.8 20 

Mo (kg) 1.3 × 105 8.9 × 104 1.1 × 105 9.5 × 104

Ni (kg) 4.2 × 106 7.3 × 106 1.7 × 107 3.3 × 106

V (kg) 2.2 × 103

 2.6 × 103 2.2 × 103 1.3 × 103

U = uranium, Th = thorium, Np = neptunium, I = iodine, Tc = technetium, Se = selenium, Mo = molybdenum, 

Ni = nickel, V = vanadium 

See Appendix A, Section A.2, for the methods of calculation.

Table 3-1b. Amount of Selected Radiological and Nonradiological Material From the 

Repository Accumulated at the Amargosa Farms Area. [1 kg = 2.2 lbs] 

Present-Day Climate Cooler/Wetter Climate 

10,000 years 1 million years 10,000 years 1 million years 

U isotopes (Ci) 0 1,030 4.0 × 10−8 1,240 

Th isotopes (Ci) 0 630 3.2 × 10−9 740 

Np-237 (Ci) 0 450 0 540 

I-129 (Ci) 2.4 1,340 2.4 1,340 

Tc-99 (Ci) 5 1,250 1,260 22,800 

Se-79 (Ci) 0 130 0 180 

Mo (kg) 1.3 × 106 2.1 × 107 1.3 × 106 2.1 × 107

Ni (kg) 0 7.3 × 107 0 7.7 × 107

V (kg) 0 4.0 × 105 0 4.0 × 105

U = uranium, Th = thorium, Np = neptunium, I = iodine, Tc = technetium, Se = selenium, Mo = molybdenum, 

Ni = nickel, V = vanadium 

See Appendix A, Section A.2, for the methods of calculation.
3-10 

some contaminants, a wetter climate leads to slightly higher concentrations compared to the 

drier climate (e.g., I-129 and Tc-99 at 10,000 years), as these nonsorbing contaminants move 

more rapidly along the flow path. In others, the calculated concentrations show little or no 

difference (e.g., Mo, V, and Ni), as the amount of contaminant moving through the system 

(the mass flux) is not strongly affected by the groundwater flow rates. 

Overall, the concentrations of radionuclides and other contaminants from the repository for 

groundwater at Amargosa Farms are uniformly very low. For example, the EPA Maximum 

Contaminant Level (MCL)2

 for alpha-particle emitting radionuclides in drinking water is 15 pCi/L, 

compared to the calculated total for all alpha-emitting radionuclides in Table 3-2 of less than 

0.1 pCi/L. 

The highest calculated total uranium concentration of 0.073 pCi/L (Table 3-2) in the 

groundwater at Amargosa Farms corresponds to less than 0.02 μg/L; for comparison, the EPA 

MCL for U in drinking water is 30 μg/L. While no MCLs have been established for the metals 

Mo and V, the calculated groundwater concentrations for these potential contaminants are all 

much lower than one part per million, which is comparable to the levels occurring naturally at 

present (Table 2-2). The calculated peak concentration of Ni in groundwater at Amargosa 

Farms, for each climate state, does not occur at 10,000 years or one million years after 

repository closure. The peak concentration for Ni in groundwater at this location is 0.011 mg/L, 

 

2

MCLs are EPA standards for drinking water quality that are established under the Safe Drinking Water Act. An MCL 

is the highest level of a contaminant that is allowed in public drinking water systems. 

Table 3-2. Peak Groundwater Concentrations of Radiological and Nonradiological 

Material From the Repository in the Aquifer at Amargosa Farms 

Present-Day Climate Cooler/Wetter Climate 

10,000 years 1 million years 10,000 years 1 million years 

U isotopes 

(pCi/L) 0 0.064 7.1 × 10−12 0.073 

Th isotopes 

(pCi/L) 0 0.005 4.2 × 10−13 0.002 

Np-237 (pCi/L) 0 0.053 0 0.069 

I-129 (pCi/L)* 0.007 0.13 0.013 0.13 

Tc-99 (pCi/L)* 4.3 8.8 5.3 8.8 

Se-79 (pCi/L)* 0 0.03 0.009 0.05 

Mo (mg/L)† 7.3 × 10−3 1.9 × 10−4 7.1 × 10−3 1.9 × 10−4

Ni (mg/L) 0 5.6 × 10−3* 0 0.011‡

V (mg/L)* 0 3.2 × 10−5 0 3.2 × 10−5

*

Peak value occurs after 100,000 years, but before 1 million years 

†

Peak value occurs at 10,000 years after closure

‡

Peak value occurs after 10,000 years, but before 100,000 years 

U = uranium, Th = thorium, Np = neptunium, I = iodine, Tc = technetium, Se = selenium, Mo = molybdenum, 

Ni = nickel, V = vanadium 
3-11 

and is estimated to occur at 70,000 years for the cooler/wetter climate. This concentration is 

much lower than the EPA National Recommended Water Quality Criteria level for Ni of 

0.61 mg/L (EPA, 2014). 

Based on the analysis described above, the NRC staff concludes that the accumulation of 

radiological and nonradiological material released from the repository to the aquifer environment 

between the postclosure compliance location and Amargosa Farms would be minimal and not 

noticeably affect the quality of the aquifer environment. Thus, the NRC staff concludes that 

the impact on the aquifer environment beyond the postclosure compliance location would 

be SMALL. 

Soil 

This section describes the accumulation of contaminants in soils at Amargosa Farms. As 

described in Chapter 2, pumping is the dominant means of groundwater discharge to the 

surface at Amargosa Farms (the only other discharge is by very limited evapotranspiration along 

the Amargosa River Section of the flow system; Section 2.2.2). Thus, any potential 

accumulation of contaminants in soils in this area would be from irrigation. The NRC staff 

calculated soil contaminant concentrations using the irrigation recycling model described in 

Appendix A, Section A.2.1. The model accounts for accumulation in soil of both radiological and 

nonradiological contaminants. Calculated values of contaminants from the repository in the 

soils at Amargosa Farms are given in Table 3-3. 

For both the present-day and potential future cooler/wetter climate, the primary radionuclides 

that would accumulate in the soil are U-238, U-235, Np-237, Pu-242, U-233, and Th-230 

(Table 3–3). Note that the nonsorbing radionuclides (I-129 and Tc-99) do not accumulate in soil 

as they remain dissolved in groundwater. The calculated soil concentrations for all of these 

radionuclides are very low for both climate states. The calculated soil concentration for the 

radionuclides in Table 3-3 correspond to a total activity of less than 1 pCi/g, and would not 

appreciably contribute to dose or other environmental impacts. 

Nonradiological contaminants show the greatest calculated concentrations at one million years 

(Table 3-3). For comparison, also shown in Table 3-3 are concentrations of some elements 

measured in sediment samples in well cuttings from Fortymile Wash, just north of the 

Amargosa Farms area (Bertetti and Prikryl, 2003). The cuttings are samples of alluvial 

sediments that are geochemically and mineralogically similar to those found in the upper part of 

the sediment column at the Amargosa Farms area. Also included in Table 3-3 are the generic 

soil screening levels for residential soil for the nonradiological contaminants (EPA, 2015). 

None of the nonradiological contaminants show any appreciable accumulation in the soil at 

Amargosa Farms, and all are well below soil screening levels or the natural abundance in local 

sediments. The estimated highest concentration of Ni in the soil at Amargosa Farms for the 

present-day climate and cooler/wetter states occurs approximately 260,000 and 70,000 years, 

respectively, after repository closure. The calculated peak soil concentration at those times is 

14 ppm. After those times for each climate state, the levels of Ni from the repository in the 

groundwater decrease, and Ni is leached from the soil by continued irrigation, leading to a lower 

concentration at one million years. 

Based on the analysis described previously, the NRC staff concludes that the accumulation in 

soils at Amargosa Farms of radiological and nonradiological material released from the 
3-12 

otherwise not noticeably affect soil concentrations. Thus, the NRC staff finds that the impact on 

soils at Amargosa Farms would be SMALL. 

Public Health 

The biosphere dose pathways used for this supplement for Amargosa Farms are the same as 

those identified in DOE’s 2008 EIS and for the RMEI in DOE’s Safety Analysis Report: 

(i) external exposure; (ii) inhalation of soil particles and from use of evaporative coolers; and 

(iii) ingestion from water, crops, animal products, fish, and soil. The NRC staff has found these 

exposure pathways for the RMEI to be acceptable as part of its safety evaluation (NRC, 2014a, 

Section 2.2.1.3.14). As further discussed in Sections A.1.3 and A.2.2 of Appendix A, the values 

for the dose conversion factors have not changed from those in the 2008 SEIS, except for 

adjustments for secular disequilibrium. Dose conversion factors for the present-day climate 

were used for both the present-day and future cooler/wetter climate. This approach is 

conservative because dose conversion factors for cooler and wetter climates would be expected 

to be lower than those for the present-day climate (Appendix A, Section A.2.3). 

The largest contributors to dose for both the present-day and wetter climate at Amargosa Farms 

are I-129, Tc-99, Np-237, and Th-230 (Figure 3-1). At 10,000 years, I-129 and Tc-99 are the 

primary contributors to dose. They do not sorb onto rock grains, but rather remain dissolved in 

water. The other radionuclides shown in Figure 3-1 sorb to various degrees, and thus arrive at 

Amargosa Farms later. The dose curves in Figure 3-1 also illustrate the effect of a wetter 

climate on transport and, consequently, dose. The higher specific discharge rate for the wetter 

climate leads to the more rapid transport of several radionuclides, and thus relatively earlier 

steady-state contributions to dose (expressed in Figure 3-1 as a shift of the dose curves to the 

Table 3-3. Peak Concentrations of Radionuclides and Chemical Materials in Soils at 

Amargosa Farms Area for Analysis Case 1 (Pumping) 

Peak Soil 

Concentration 

(ppm) 

Present-Day 

Climate 

Cooler/Wetter 

Climate Local 

Natural 

Sediments* 

Soil 

Screening 

Level 10,000 †

years 

1 million 

years 

10,000 

years 

1 million 

years 

Np-237 0 8.0 × 10−5 0 1.0 × 10−4

 — — 

Pu-242 0 0 0 3.1 × 10-5 — — 

U-235 0 5.2 × 10−4 0 5.8 × 10−4

 — — 

Th-230 0 3.6 × 10−6 0 1.2 × 10−6 — — 

U-238 0 0.02 0 0.025 — — 

U-233 0 5.7 × 10−6 0 6.5 × 10−6

 — — 

Mo‡ 0.08 0.002 0.04 0.001 — 390 

Ni 0 14§ 0 14║ 17.8 1,500 

V§ 0 0.022 0 0.012 22.4 390 

U (all isotopes) 0 0.023 0 0.026 3.9 230 

*ppm, from Bertetti and Prikryl (2003) 

†

ppm, values shown are for total Mo and V, and for soluble salts of Ni and U in residential soil (EPA, 2015) ‡

 Peak value occurs at 10,000 years after closure 

§ Peak value occurs after 100,000 years, but before 1 million years 

║

 Peak value occurs after 10,000 years, but before 100,000 years 

Np = neptunium, Pu = plutonium, U = uranium, Th = thorium, Mo = molybdenum, Ni = nickel, V = vanadium 

Soil radionuclide concentrations assume the contamination is in the top 0.25 m [0.82 ft] of soil and the soil bulk 

density is 1,500 kg/m3 [94 lb/ft3] 
3-13 

Figure 3-1. Dose History of Selected Radionuclides at Amargosa Farms for the 

Present-Day (Top) and Cooler/Wetter (Bottom) Climates 

left for the wetter climate, as compared to the curves for the present-day climate). Peak doses, 

considering all radionuclides, are shown in Table 3-4 for 10,000 and one million years for both 
3-14 

climate states. The peak dose of 1.3 mrem/yr [0.013 mSv/yr] in Table 3-4 is lower than the 

dose from natural background levels of approximately 300 mrem/yr [3.0 mSv/yr] (including 

radon) for Amargosa Valley, and lower than that calculated for the RMEI at the postclosure 

compliance location closer to the repository (DOE, 2008b). Furthermore, the peak values 

estimated for 10,000 and one million years for the present-day and cooler/wetter climate are 

much lower than the NRC annual dose standards for a Yucca Mountain repository in 

10 CFR Part 63 {15 mrem [0.15 mSv] for the first 10,000 years, and 100 mrem [1 mSv] for 

one million years, after permanent closure}. 

Potential health effects from the nonradiological contaminants are considered for a nominal 

body intake from ingestion of contaminated water, assuming daily intake for a 70-kilogram 

person drinking 2 liters of water daily. Human health impacts of the nonradiological 

contaminants are assessed by comparing daily intakes with EPA’s Oral Reference Dose 

standard (EPA, 1999a,b; 1997a,b; 1994). Estimated values of peak daily intakes for each of the 

nonradiological contaminants are summarized in Table 3-5 for the one-million-year period. In 

accord with the calculations for the aquifer environment between the postclosure compliance 

location and Amargosa Farms, the peak daily intake for Ni is estimated to occur at 

260,000 years. The peak value of 0.0023 mg/kg [3.7 × 10−8

 oz/lb] body weight/day corresponds 

to the peak values in groundwater Ni concentration for the cooler/wetter climate. The calculated 

peak daily intake for Ni for the present-day climate is lower than that estimated for the 

cooler/wetter climate. The estimated values of daily intake are all much lower than the EPA 

Oral Reference Doses. 

Based on the above analyses of radiological and nonradiological material released from the 

repository to the Amargosa Farms area, the NRC staff finds that the impact to public health 

beyond the postclosure compliance location would be SMALL, as the contribution from both 

radiological and nonradiological contaminants is generally nominal, and in all cases below 

applicable impact and reference standards and limits. 

3.1.2 Analysis Case 2: Surface Discharge Downstream of Amargosa Farms 

This section addresses impacts from surface discharge at downstream locations in the case of 

limited or no pumping at Amargosa Farms. For this case, contaminants from the repository 

would travel past the Amargosa Farms area and could reach the surface environment at the 

downstream locations discussed in Section 2.3. This Analysis Case considers both the present 

day and cooler/wetter climate states. 

In the 2002 EIS, DOE scaled results from the RMEI location to account for groundwater 

dispersion to estimate impacts at 30 and 60 km [19 and 37 mi] from the repository, which are 

approximately the distances from the repository to Amargosa Farms and Alkali Flat, 

respectively. In the 2002 EIS and 2008 SEIS, DOE stated that the contaminants would 

discharge to the surface at Alkali Flat, but the DOE discussion of these impacts is limited to a 

statement that no detrimental radiological impacts on plants and animals are expected. 

In this supplement, impacts at natural discharge sites along the groundwater pathway beyond 

the postclosure compliance location are analyzed. This Analysis Case addresses discharge of 

contaminants by springs or playas at the State Line Deposits/Franklin Well area (which would 

occur under a cooler/wetter climate only), the springs at Furnace Creek, and the playa/salt pan 

at Middle Basin of Death Valley. Results from the DVRFS groundwater model indicate that in 

the absence of pumping of the aquifer at Amargosa Farms, the predominant discharge site of 
3-15 

contaminants transported from Yucca Mountain for the present-day climate would be Middle 

Basin in Death Valley (Chapter 2; see also Belcher and Sweetkind, 2010). 

Along the way to Middle Basin, some amount of groundwater contaminants may be discharged 

at the springs in the Furnace Creek area. In a future wetter climate, another potential location 

for natural discharge is springs in the State Line Deposits/Franklin Well area. In addition, 

groundwater modeling indicates that beyond the State Line area, a very small fraction (2 out of 

8,024 modeled particles, or 0.03 percent) of contaminants may move southward toward 

Alkali Flat, rather than Middle Basin (Chapter 2). This discharge location is considered as an 

alternative pathway to the expected pathway (State Line–Furnace Creek–Middle Basin). 

Descriptions of potential impacts are provided for natural discharge at the State Line 

Deposits/Franklin Well area (Section 3.1.2.1), Furnace Creek and Middle Basin of Death Valley 

(Section 3.1.2.2), and Alkali Flat (Section 3.1.2.3). For each of the locations, the peak impact is 

estimated by conservatively assuming that the entire plume of potential contaminants 

discharges at that single location. This is conservative because it is likely that radiological and 

nonradiological contaminants in the plume would discharge at multiple surface locations that 

may be active at the same time. 

3.1.2.1 State Line Deposits/Franklin Well Area 

As discussed in Chapter 2, the State Line Deposits area is located approximately 21 km [13 mi] 

beyond the postclosure compliance location, or 39 km [24 mi] from the repository along the 

Table 3-4. Peak Annual Dose Estimates for the Amargosa Farms Area 

Peak Annual Dose (mrem/yr)* 

10,000 years 1 million years 

Present-day Climate 0.22 1.1 

Cooler/Wetter Climate 0.25 1.3 

*1.0 mrem/yr = 0.01 mSv/yr

Table 3-5. Impact of Nonradiological Contaminants at Amargosa Farms Using 

Estimates of Body Intake

Peak Daily 

Intakes 

(mg/kg bodyweight/day) 

Present-Day Climate Cooler/Wetter Climate EPA Oral 

Reference 

Dose 10,000 years 1 million years 10,000 years 1 million years 

Mo* 1.5 × 10−3 4.1 × 10−5 1.5 × 10−3 4.1 × 10−5 5.0 × 10−3

Ni 0 1.2 × 10−3 † 0 2.3 × 10−3 ‡ 2.0 × 10−2

V‡ 0 6.7 × 10−6 0 6.7 × 10−6 9.0 × 10−3

U (all isotopes) 0 3.5 × 10−6 0 3.8 × 10−6 3.0 × 10−3

*

Peak value occurs at 10,000 years after closure

†

Peak value occurs after 100,000 years, but before 1 million years 

‡

Peak value occurs after 10,000 years, but before 100,000 years 

Mo = molybdenum, Ni = nickel, V = vanadium, U = uranium 
3-16 

Yucca Mountain flow path. These paleospring deposits occur where the Amargosa River and 

Fortymile Wash join. The water table approaches the ground surface in the present-day 

climate, and reached the ground surface during past wetter climates to produce deposits that 

formed in playas, springs, marshes, and ponds (Section 2.3.4). The Franklin Well area refers to 

the narrow band of dense vegetation along the Amargosa River channel at the southern extent 

of the State Line Deposits area. In the present-day climate, the Amargosa River only flows after 

significant precipitation events in most of Amargosa Desert, including in the Franklin Well area. 

For the present-day climate, a small amount of natural discharge occurs at the Franklin Well 

area as evapotranspiration from a dominantly mesquite thicket along the river channel. 

To estimate impacts in the State Line/Franklin Well area, the transport and biosphere model 

inputs and assumptions are derived from the present hydrologic characteristics and 

environmental inferences from the paleospring deposits observed in the region. In the 

present-day climate, discharge occurs at the Franklin Well area only as evapotranspiration in 

the Amargosa River channel. For a cooler/wetter climate, discharge is projected to occur in the 

entire State Line Deposits/Franklin Well area in a combination of springs, pools, marshes, and 

wet and dry playas. The discharge rate during a future cooler/wetter climate can be estimated 

based on the extent of the deposits and similar modern springs in the region. One modern 

analog, albeit on a larger scale, may be Ash Meadows. The present-day Ash Meadows area of 

springs, marshes, pools and playas is approximately twice the area of the State Line deposits, 

and has similar types of discharge to that indicated for the State Line Deposits area. 

Present day discharge at Ash Meadows is estimated to be 60,372 m3

/day [17,865 acre-ft/yr] 

(Belcher and Sweetkind, 2010, Table F-4). Prior to water use restrictions related to Devils Hole, 

water was diverted from pools and ponds, and was pumped from the ground for agriculture in 

Ash Meadows. Whereas limited water diversion for agriculture at a future, wetter State Line 

Deposits area is possible, extensive agriculture in the area of the State Line Deposits is unlikely 

due to the high concentrations of salts in the soils. Therefore, biosphere and dose pathway 

modeling for a cooler/wetter climate at the State Line Deposits/Franklin Well area includes 

(i) inhalation of resuspended dust from wet and dry playas, (ii) ingestion of water and soil, and 

(iii) subsistence farming using water diverted from less saline pools and springs. Recycling and 

recapture of irrigated water are not applicable for water diverted from pools and springs for 

agriculture because unlike the case of well-pumping irrigation, any irrigation water diverted from 

springs or pools is typically used downstream from its source, and thus the contaminants pass 

only once through the local soil. Transport properties for the State Line Deposits/Franklin Well 

area, except for the distance, are the same as used for the calculations for Amargosa Farms, as 

the characteristics of the aquifer are the same. For the estimated impacts at the State Line 

area, the NRC staff conservatively assumes that the entire plume discharges to that location. 

Aquifer Environment 

Several features of the aquifer environment at the State Line Deposits/Franklin Well area 

indicate that groundwater concentrations and accumulations of sorbed material onto sediments 

would be lower than in the aquifer environment at Amargosa Farms: 

 The area is a short distance further downstream from the Amargosa Farms area. The 

amount of radiological and nonradiological material expected in the aquifer environment, 

both sorbed to alluvial sediment grains and dissolved in the groundwater would therefore 

be slightly less than at Amargosa Farms due to additional dispersion and decay. Except 

for the additional distance, the transport processes to Amargosa Farms and to the State 

Line Deposits/Franklin Well area are similar. 
3-17 

 No additional concentrating mechanisms occur in State Line Deposits/Franklin Well 

area, such as the recycling/infiltration of water used for agriculture, compared to those at 

the aquifer environment at Amargosa Farms. 

 Whereas there are indications that water from the carbonate aquifer contributed to the 

paleospring deposits at the State Line Deposits/Franklin Well area (discussed in 

Section 2.3.4), the groundwater is still dominantly derived from an alluvial/volcanic 

aquifer, based on its chemical characteristics. Any amount of water from the underlying 

uncontaminated carbonate aquifer would dilute the contaminants in the groundwater at 

this location, and lower their concentrations in the aquifer. 

 Groundwater from the northwest (Amargosa Desert) and south (Funeral Mountain 

alluvial fan) contribute to the groundwater flow in the area. These uncontaminated 

sources would similarly reduce aquifer contaminant concentrations. 

As noted above, the NRC staff found the impacts to the aquifer environment in the 

Amargosa Farms area to be SMALL. As the impacts at the State Line Deposits/Franklin Well 

area would be less than those at Amargosa Farms, the NRC staff finds that the impacts on the 

aquifer environment at the State Line Deposits/Franklin Well area would be SMALL. 

Soil 

This section describes the accumulation of repository materials in soils at the State Line 

Deposits/Franklin Well area for the wetter climate. Because of the very limited area where the 

water table is potentially close enough to the ground surface for contaminants to enter the soil in 

present-day climate conditions, an insignificant amount of precipitation of radiological and 

nonradiological contamination from the repository is expected to occur. However, in a 

cooler/wetter climate state where the water table could rise approximately 20 to 30 m 

[66 to 98 ft] (Section 2.3.4), a larger area would be affected and soil concentrations of 

contaminants could be greater. 

The NRC staff uses two approaches to estimate the soil concentration of contaminants for the 

cooler/wetter climate to account for the range of processes that occur in this type of 

environment. These approaches are for contaminants in evaporite minerals at a wet playa-type 

discharge setting, and for contaminants in sediments collecting in a salt marsh-type discharge 

setting. These are the environments inferred from the paleospring deposits in this location 

(Section 2.3.4). In the first approach, evaporation from a wet playa-type of discharge site is 

conservatively assumed for the entire State Line Deposits/Franklin Well area. This approach 

leads to the greatest calculated contaminant concentration in soils at the State Line 

Deposits/Franklin Well area, as it assumes extensive formation of evaporite minerals in 

playa-type areas, which strongly concentrates contaminants from groundwater. The 

concentrations of contaminants in soil and evaporite deposits within the wet playa are calculated 

using the estimated concentrations of the contaminant and total dissolved solids (TDS) content 

of the groundwater. This model for soil concentration assumes that as water is lost by 

evaporation, contaminants in groundwater are incorporated into newly formed evaporite 

minerals. The contaminant concentration is higher in evaporites formed from relatively dilute 

water (low TDS) than from water with the same concentration of contaminants but a greater 

initial content of (noncontaminant) dissolved material, as a greater amount of evaporation is 

needed to form evaporites from water with a low amount of TDS. These calculations 

conservatively use water with a relatively low TDS [257 ppm, as measured in groundwater from 

well J-13 in Fortymile Wash (DOE, 2014a)]. An additional conservatism is that the model 
3-18 

assumes that the “soil” is composed entirely of minerals formed by evaporation of the 

groundwater. While this can be observed in some local areas of extreme aridity (for example, in 

salt pans in Death Valley), wet and dry playas typically contain significant amounts of 

nonevaporite material, with mineral grains transported to the playa by wind or running water 

(like the playa environments indicated by the paleospring deposits in the State Line area; 

Section 2.3.4). This assumption thus represents a conservative means of estimating 

contaminant concentrations in the soil. 

The second approach assumes accumulation of contaminants in soils formed from sediments in 

spring-fed marshes and pools. Unlike the first approach, this method does not assume 

complete evaporation of the groundwater. Instead, this approach assumes that contaminants 

accumulate on sediment that forms soils in a marsh/pool environment like that seen in nearby 

wet areas, such as Ash Meadows. The calculation of soil contaminant concentration used in 

this approach is similar to that described for the Amargosa Farms area (Section 3.1.1), except 

that no recapture and recycling is included. Table 3-6 provides the estimated radiological and 

nonradiological contaminant soil concentrations for both approaches. 

The calculated soil concentrations in Table 3-6 show similar patterns to Amargosa Farms for 

sorbing and nonsorbing radionuclides and metals. Estimates of sorbing radionuclide (Np-227 

and U isotopes) and metal (Ni and V) contaminants are zero at the State Line Deposits/Franklin 

Well area at 10,000 years, for both calculation models. The nonsorbing contaminants 

(I-129, Tc-99, and Mo) are estimated to be present in low concentrations at 10,000 years. As 

expected, the calculated concentrations are significantly greater for the more-conservative 

evaporite model, particularly for the nonsorbing contaminants, but are still very low. 

At one million years, the calculations show all of the contaminants from the repository present in 

the soils at the State Line Deposits/Franklin Well area, with most concentrations still very low. 

As expected, the more conservative evaporite model gives a greater calculated concentration 

than the salt marsh model for those contaminants estimated to occur in the soil. Even using the 

evaporite model, the values calculated for all contaminants are all very low for both time 

periods. As was the case for Amargosa Farms, the estimated peak soil concentration for Ni at 

this location occurs between 10,000 and one million years after repository closure, at 

approximately 84,000 years, and reaches a maximum of 3.4 ppm using the Salt Marsh Model 

for a short period of time before decreasing. The estimated concentrations for all of the 

nonradiological contaminants are lower than the EPA generic soil screening levels (Table 3-3). 

Based on the analysis above for the accumulation in soils of radiological and nonradiological 

contaminants from the repository and the associated conservative assumptions used in the 

analysis, the NRC staff finds that the impact on soils at State Line Deposits/Franklin Well area 

would be SMALL. 

Public Health 

Combined radionuclide peak dose (considering all radionuclides) and body intake for 

nonradiological contaminants are given in Table 3-7 for 10,000 and one million years for the 

cooler/wetter climate, and the contributors to radiological dose are shown in Figure 3-2. The 

largest contributors to radiological dose for both the present-day and the wetter climate at the 

State Line Deposits area are I-129, Tc-99, Np-237, and Pu-242 (Figure 3-2). At 10,000 years, 

I-129 and Tc-99 are the primary contributors to dose. They do not sorb onto rock grains, but 

rather remain dissolved in water. The other radionuclides in Figure 3-2 sorb to various degrees, 

and thus arrive later. 
3-19 

Table 3-6. Peak Soil Concentrations of Radiological and Nonradiological 

Contaminants at the State Line Deposits/Franklin Well Area in a 

Cooler/Wetter Climate State, Calculated Using the Evaporite and Salt 

Marsh Soil Models 

Concentration 

(ppm) 

Evaporite Soil Model (Playa) Salt Marsh Soil Model 

10,000 years 1 million years 10,000 years 1 million years 

Np-237 0 7.1 × 10−4 0 2.7 × 10−5

U-235 0 3.1 × 10−3 0 1.5 × 10−4

U-238 0 0.13 0 6.6 × 10−3

U-233 0 3.4 × 10−5 0 1.7 × 10−6

Tc-99* 3.0 × 10−3 3.8 × 10−3 2.5 × 10−6 1.7 × 10−6

I-129* 5.5 × 10−4 5.5 × 10−3 7.8 × 10−6 5.1 × 10−5

Mo† 52 1.4 0.011 3.1 × 10−4

Ni‡ 0 75 0 3.4 

V* 0 0.23 0 0.003 

U (all isotopes) 0 0.14 0 0.007 

*

Peak value occurs after 100,000 years, but before 1 million years 

†

Peak value occurs at 10,000 years after closure 

‡

Peak value occurs after 10,000 years, but before 100,000 years 

U = uranium, Th = thorium, Np = neptunium, I = iodine, Tc = technetium, Se = selenium, Mo = molybdenum, 

Ni = nickel, V = vanadium

Table 3-7. Peak Annual Dose and Body Intake Estimates for the Cooler/Wetter Climate 

at the State Line Deposits/Franklin Well Area 

10,000 years 1 million years 

Peak Dose (mrem/yr)*

0.034 0.28 

Body Intake Estimates Oral Reference 

10,000 years 1 million years Dose 

Mo (mg/kg body-weight/day)* 3.8 × 10−4 1.0 × 10−5 5.0 × 10−3

Ni (mg/kg body-weight/day)† 0 5.5 × 10−4 2.0 × 10−2

V (mg/kg body-weight/day)‡ 0 1.7 × 10−6 9.0 × 10−3

U (mg/kg body-weight/day) 0 1.0 × 10−6 3.0 × 10−3

*

Peak value occurs at 10,000 years after closure

†

Peak value occurs after 10,000 years, but before 100,000 years 

‡

Peak value occurs after 100,000 years, but before 1 million years 

Note: 1.0 mrem/yr = 0.01 mSv/yr 

Mo = molybdenum, Ni = nickel, V vanadium, U = uranium 

Estimates of dose and body intake for the present-day climate are extremely small because of 

the small area affected (Franklin Well area) and limited amount of evapotranspiration. For the 

cooler/wetter climate, the peak dose of 0.28 mrem/yr [0.0028 mSv/yr] is substantially lower 

than the dose from natural background levels {approximately 300 mrem/yr [3.0 mSv/yr], 

including radon} for the Amargosa Farms area. Peak values estimated for 10,000 and one 

million years for the cooler/wetter climate are much lower than the NRC annual dose 

standards for a Yucca Mountain repository in 10 CFR Part 63 {15 mrem [0.15 mSv] for the first 

10,000 years, and 100 mrem [1 mSv] for one million years, after permanent closure}. 
3-20 

Figure 3-2. Dose History of Selected Radionuclides at State Line Deposits/Franklin 

Well Area for the Cooler/Wetter Climate 

The peak daily intake value for Ni at the State Line Deposits/Franklin Well area corresponds to 

its maximum groundwater and soil concentration at this location. The maximum of 0.001 mg/kg 

body weight/day occurs at approximately 88,000 years after repository closure. For all of the 

nonradiological contaminants at this location, the estimates of body intake are significantly lower 

than the EPA Oral Reference Dose. Based on the analyses above of radiological and 

nonradiological material potentially released from the repository to the State Line 

Deposits/Franklin Well area, the NRC staff finds that the impact to public health would 

be SMALL. 

3.1.2.2 Furnace Creek and Middle Basin 

The Furnace Creek area and Middle Basin of Death Valley are located approximately 56 km 

[35 mi] beyond the postclosure compliance location. As discussed in Section 2.2.2, under 

scenarios in which there is no pumping at the Amargosa Farms area, groundwater modeling 

indicates that the majority of contaminants transported from Yucca Mountain would be 

discharged in Middle Basin of Death Valley (Belcher and Sweetkind, 2010). Contaminated 

groundwater could also discharge at the springs in the Furnace Creek area, a short distance 

upgradient from Middle Basin (Belcher and Sweetkind, 2010; DOE, 2014a). For the estimated 
3-21 

impacts at Furnace Creek or Middle Basin, the NRC staff conservatively assumes that the entire 

plume discharges at that location. For these locations, the impact types are the same as for 

Amargosa Farms (Section 3.1.1): (i) the amount of contaminants from the repository in the 

groundwater system, (ii) the concentration of contaminants in the groundwater, (ii) the 

concentration of contaminants in soils, and (iv) the radiological dose and body intake of 

contaminants for the relevant exposure pathways. Biosphere dose conversion factors for the 

Furnace Creek and Middle Basin areas are based on exposures to full-time residents in the 

local environments (see Appendix A, Section A.2.2). 

The transport model uses a path length of 56 km [35 mi] and transport properties that are 

distance-weighted for each segment of the pathway (see Appendix A, Section A.1.2). The 

specific inputs and assumptions used to determine the impacts are: 

 The mass flux of radiological and nonradiological material reaching the potential 

discharge locations at Furnace Creek or Middle Basin is calculated using observations of 

spring discharge and evaporation losses. Total discharge from the springs at Furnace 

Creek is 2,294 acre-ft/yr [2.83 million m3

/yr]. Discharge in the playa environment at 

Middle Basin occurs through evaporation, and observed evaporation losses were 

1,962 acre-ft/yr [2.4 million m3

/yr] at that location (Belcher and Sweetkind, 2010; 

Table F-4). 

 Transport in the aquifer to Furnace Creek is calculated using a value of 0.00046 m/day 

[0.0015 ft/day] for the specific discharge (flow rate) along the 56 km [35 mi] path in the 

present-day climate (see Appendix A, Section A.1.2). For the wetter climate, the specific 

discharge is multiplied by a factor of 3.9 (DOE, 2014a; 2008b, Section 2.3.9). An 

average porosity in the aquifer of 0.11 is used for both climate states. 

 A value of 257 ppm is used for the groundwater TDS content. This is the same 

conservative value used in the State Line Deposits area analysis, and lower than values 

typically observed at discharges from springs at Furnace Creek. As discussed in 

Section 3.1.2.1, using a lower TDS value is conservative. The TDS value is used to 

determine the total mass of evaporite deposits that could form. This affects the 

calculated concentration of contaminants in evaporite deposits. 

 Dose conversion factors used in the analyses are derived from DOE (2008b, 

Table 2.3.10-12) with adjustments for secular disequilibrium (see Appendix A, 

Section A.1.2). 

All radiological and nonradiological contaminants in the source term are analyzed in the 

transport models, but only the predominant elements reaching the affected environment of 

Furnace Creek or Middle Basin are described in detail below. Estimates for other contaminants 

produce extremely low concentration values, and they do not contribute to estimates of dose or 

toxic exposure. For this Analysis Case 2 (Discharge at Furnace Creek or Middle Basin), the 

radionuclides that are significant contributors to dose are Tc-99 and I-129 for both the present 

day and wetter climates. Because of sorption (and to a lesser degree, radioactive decay) along 

the long transport path, none of the other analyzed radionuclides reach the Death Valley 

locations and contribute to dose within the one-million-year analysis period for either climate 

scenario. Similar to the radionuclides, only the nonsorbing nonradiological contaminant, Mo, 

reaches the discharge locations in Death Valley over the one-million-year analysis period. 
3-22 

Aquifer Environment 

This section describes (i) the amount of material from the repository that could be deposited in 

the aquifer environment between the postclosure compliance location at 18 km [11 mi] and the 

Death Valley discharge locations 56 km [35 mi] down the flow path, and (ii) the concentration of 

contaminants in the groundwater at the Death Valley discharge locations. 

The amount of radiological and nonradiological contaminants in the aquifer environment 

between the postclosure compliance location and the potential Death Valley discharge 

locations, based on mass balance calculations, is provided in Table 3-8. The term “aquifer 

environment” includes both the rock and water along the groundwater flow path from 

Yucca Mountain. Thus, the contaminants are both dissolved in the water and sorbed onto the 

porous media of the aquifer matrix, which includes the alluvial fill of the Amargosa Desert and 

the carbonate rocks underlying the Funeral Mountains. The values in Table 3-8 are calculated 

by subtracting the mass of material accumulated at the discharge locations from the cumulative 

mass released to the postclosure compliance location. 

Many of the contaminants shown in Table 3-8 (U, Th, Np, Se, Ni, and V; all but Tc-99, I-129, 

and Mo) do not discharge to the surface in Death Valley within one million years due to the 

decay of radionuclides and sorption effects. For these contaminants, all of the material that is 

released beyond the postclosure compliance location (which would have been discharged at 

Amargosa Farms at the present pumping rates for Analysis Case 1) is retained within the 

aquifer system and does not discharge to the surface. 

Table 3-9 presents the estimated average concentrations of the radiological and nonradiological 

contaminants in groundwater discharging to the surface at the Furnace Creek area for this 

Analysis Case (limited or no pumping at Amargosa Farms). The concentrations are calculated 

by dividing the mass flux to Death Valley by the discharge rate at Furnace Creek. Under the 

lower flow volumes associated with the present-day climate, no contaminants reach the Furnace 

Creek area before 10,000 years after repository closure. Estimated contaminant concentrations 

at one million years are greater for the present-day climate state because there is less dilution 

of the contaminants in the groundwater. Although the contaminants arrive at Furnace Creek 

earlier in the cooler/wetter climate state, the contaminant concentration is lower. 

Groundwater at Middle Basin would have similar concentrations, but as described in 

Section 2.3.3, there is presently no spring discharge at Middle Basin, and it is unlikely that 

free-flowing water would appear in that wet playa environment (see discussion in Appendix A, 

Section A.2.2). Because sorption and decay processes significantly impact transport over the 

long transport pathway to Death Valley, only nonsorbing contaminants (I-129, Tc-99, and Mo) 

are found in groundwater discharging to the surface in Death Valley. 

At Furnace Creek, the maximum concentration of Mo in the groundwater occurs approximately 

58,000 years after repository closure for the present-day climate (under the cooler/wetter 

climate, the peak arrives at 20,000 years after closure, at a lower concentration). The major 

release of this contaminant from the repository occurs fairly early after repository closure 

(see Appendix A), and as a nonsorbing element, transport of Mo is not significantly delayed in 

the aquifer. The estimate of the maximum Mo concentration in the groundwater is 0.05 mg/L 

and declines after this time. As noted previously, EPA has not set an MCL or National 

Recommended Water Quality Criteria level for Mo, but the peak concentration is much lower 

than 1 ppm and near the detection limit for Mo for the levels given in Table 2-1. 
3-23 

Because the only radiological and nonradiological material reaching Furnace Creek and 

Middle Basin are small amounts of Tc-99, I-129, and Mo, the NRC staff finds that the impact on 

the aquifer environment at Furnace Creek and Middle Basin would be SMALL. 

Soil 

This section describes the accumulation of potential contaminants from the repository in soils at 

Middle Basin or Furnace Creek. The concentrations of contaminants in soil and evaporite 

Table 3-8. Amount of Radiological and Nonradiological Material (From the Repository) 

in the Aquifer Environment Between the Postclosure Compliance Location 

and Death Valley 

Present-Day Climate Cooler/Wetter Climate 

10,000 years 1 million years 10,000 years 1 million years 

U isotopes (Ci) 1.5 1,320 1.5 1,320 

Th isotopes (Ci) 0.18 790 0.18 790 

Np-237 (Ci) 1.4 580 1.4 580 

I-129 (Ci) 2.5 65 2.2 15 

Tc-99 (Ci) 1,260 1,520 1,160 435 

Se-79 (Ci) 5.8 200 5.8 200 

Mo (kg) 1.4 × 106 2.9 × 105 1.4 × 106 1.3 × 105

V (kg) 2.2 × 103 4.0 × 105 2.2 × 103 4.0 × 105

Ni (kg) 1.2 × 106 8.0 × 107 1.2 × 106 8.0 × 107

U = uranium, Th = thorium, Np = neptunium, I = iodine, Tc = technetium, Se = selenium, 

Mo = molybdenum, Ni = nickel, 

Table 3-9. Peak Concentrations of Radiological and Nonradiological Material From the 

Repository Discharging in Groundwater at Furnace Creek, Death Valley 

Present-Day Climate Cooler/Wetter Climate 

10,000 years 1 million years 10,000 years 1 million years 

U isotopes (pCi/L) 0 0 0 0 

Th isotopes (pCi/L) 0 0 0 0 

Np-237 (pCi/L) 0 0 0 0 

I-129 (pCi/L)* 0 0.97 0.02 0.24 

Tc-99 (pCi/L)* 0 58 9.3 16 

Se-79 (pCi/L) 0 0 0 0 

Mo (mg/L)† 0 0.05 0 0.013 

V (mg/L) 0 0 0 0 

Ni (mg/L) 0 0 0 0 

*Peak value occurs after 100,000 years, but before 1 million years 

†

Peak value occurs after 10,000 years, but before 100,000 years 

U = uranium, Th = thorium, Np = neptunium, I = iodine, Tc = technetium, Se = selenium, Mo = molybdenum, 

V = vanadium, Ni = nickel
3-24 

deposits within the wet playa are calculated using the estimated concentrations of the 

contaminant and TDS content of the groundwater, as in the evaporite model calculation for the 

State Line Deposits area (Section 3.1.2.1). Essentially, as water is lost due to evaporation, 

forming evaporites and other minerals, the contaminants in groundwater are incorporated into 

the newly formed solids. The concentration of the contaminant in the resulting solid is 

calculated by dividing the contaminant concentration in the groundwater by the TDS of the 

groundwater. The same conservative low value of TDS (257 ppm) is used here as in the 

previous evaporite model calculations (Section 3.1.2.1). The measured values of spring 

discharge waters at Furnace Creek are approximately 600 ppm TDS (Steinkampf and Werrell, 

1998). Using this value for TDS in the evaporite model would decrease the calculated 

concentration in the soil to less than half that of the present estimate. Table 3-10 provides the 

calculated concentrations of radiological and nonradiological contaminants in soil and evaporite 

at Middle Basin. These values are derived from estimates in DOE (2014a, Table B-15) and the 

observed evaporation-driven discharge rates at Middle Basin (Belcher and Sweetkind, 2010). 

The values calculated for Middle Basin are limiting for possible soil accumulations at 

Furnace Creek. This is because any potential soil contamination from natural spring discharge 

at Furnace Creek would likely occur in a marsh/pool environment, rather than the wet playa 

environment in the topographic low at Middle Basin. As discussed in Section 3.1.2.1, modeling 

contaminant accumulation as a process that forms evaporites is very conservative, and results 

in greater concentrations than would form in an environment with less extreme evaporation. 

Potential accumulations of contaminants in soil at Furnace Creek are therefore expected to be 

less than those shown in Table 3-10 for the Middle Basin playa. 

No radionuclide contaminants reach Middle Basin within 10,000 years in the present-day 

climate state, even with no pumping in Amargosa Farms. In the cooler/wetter climate state, 

I-129 and Tc-99 are present in Death Valley groundwater at 10,000 years, and therefore would 

be found in Middle Basin soils, although at very low levels. Due to radioactive decay, maximum 

Tc-99 soil/evaporite concentration is reached at about 358,000 years for the present-day climate 

and at about 328,000 years in the cooler/wetter climate; both climates have slightly smaller 

Tc-99 peaks at approximately 50,000 and 550,000 years. The I-129 concentration continues to 

increase slowly over the one-million-year period in both climate states. 

For nonradiological contaminants, only the nonsorbing element Mo reaches Middle Basin. 

Under the present-day climate scenario, Mo reaches a maximum soil/evaporite concentration at 

about 58,000 years. The estimated maximum value is 208 ppm under the present-day climate 

state. The maximum value occurs slightly earlier for the cooler/wetter climate, but is lower. The 

maximum value decreases in the soil as the groundwater concentration decreases over time. 

This maximum is lower than the EPA soil screening level of 390 ppm for Mo in residential soils 

(Table 3-3). Studies of evaporation pits collecting irrigation water in the San Joaquin Valley 

have measured similar amounts of natural Mo concentrations (up to 94 ppm in soil/evaporite) as 

observed in the wetter climate scenario (Tanji et al., 1992). As discussed for the evaporite 

model results at the State Line Deposits area (Section 3.1.2.1), the environments where 

evaporites form are generally inhospitable due to the high salt concentrations and lack of 

potable water. 

Because there is very little accumulation of radiological contaminants (only Tc-99 and I-129, and 

at very low levels) in soils at Middle Basin or Furnace Creek, and because accumulations of the 

one nonradiological contaminant present (Mo) is likely to be elevated only in barren and 

uninhabitable portions of these areas, the NRC staff finds that soil impacts from radiological and 

nonradiological contaminants associated with natural groundwater discharges at Middle Basin 

and Furnace Creek would be SMALL. 
3-25 

Public Health 

Biosphere dose pathways used in DOE’s 2008 SEIS are very similar to those used for the 

postclosure compliance location, as the latter are based on the diet and living style of the people 

who now reside in the Town of Amargosa Valley, Nevada (as prescribed in 10 CFR 63.312). 

However, there are some significant modifications necessary for the application of these 

pathways to residents in areas of natural surface discharge, like Death Valley, as compared to 

the groundwater pumping areas of Amargosa Farms. These include, in the absence of 

extensive agriculture, the lack of significant irrigation and groundwater recycling. In 

Death Valley, most discharge is by evapotranspiration (DOE, 2014a). In the Furnace Creek 

area, much of the natural spring discharge is captured in engineered structures for use in local 

facilities (tourist lodgings and housing for National Park service personnel). And as previously 

noted (Section 2.1.1), the Timbisha Shoshone tribal community near Furnace Creek has 

federally appropriated rights to 92 acre-feet per year [0.113 million m3/yr] of surface 

and groundwater. 

The biosphere dose pathways used in this supplement for the Death Valley locations include 

(i) external exposure, (ii) inhalation of soil/evaporite particulates and water vapor from 

evaporative coolers, and (iii) ingestion of water and soil/evaporite particulates. Ingestion of 

locally-grown crops, animal products, and fish was not included as a pathway for the natural 

discharge areas of Death Valley because there is very little current agricultural production in the 

Furnace Creek area (only a small commercial date farm) and wet playas such as Middle Basin 

are not suited for future agricultural production due to the salt content of the soil and water. 

Likewise, for wet playa-type discharges (such as Middle Basin), ingestion of water and exposure 

from evaporative coolers were also excluded as pathways because the saline water in the wet 

playa is not potable. Even in a cooler/wetter climate, the wet playa water would be unsuitable 

for use as drinking water or for use in agriculture. 

For assessing impacts at the natural discharge locations in Death Valley, this supplement uses 

biosphere dose conversion factors similar to those developed based on exposure rates for 

full-time residents of the Amargosa Farms area and used in the 2008 SEIS. The factors are 

modified for the different exposure pathways in Death Valley compared to Amargosa Farms, 

and they include corrections to account for secular disequilibrium. Dose conversion factors for 

the present-day climate are used for both present-day and future wetter climate scenarios 

because the dose conversion factors for cooler and wetter climates would be lower than those 

used for the present-day climate. Appendix A, Section A.2.3 provides more information on the 

biosphere dose pathways and dose conversion factors used in this supplement. 

Table 3-10. Peak Soil/Evaporite Contaminant Concentrations for Middle Basin, 

Death Valley 

Present-Day Climate Cooler/Wetter Climate 

10,000 years 1 million years 10,000 years 1 million years 

I-129 (ppm)* 0 0.025 0.0005 0.006

Tc-99 (ppm)* 0 0.015 0.002 0.004

Mo (ppm)† 0 208 2.1 × 10−6 61 *

Peak value occurs after 100,000 years, but before 1 million years 

†

Peak value occurs after 10,000 years, but before 100,000 years 

I = Iodine, Tc = technetium, Mo = molybdenum
3-26 

Furnace Creek Radiological Contaminants 

Peak annual dose estimates for Furnace Creek are given in Table 3-11 for both climate states. 

As discussed in the previous sections on impacts on the aquifer and soil, only a limited amount 

of radionuclides reach the natural discharge locations in Death Valley. The principal 

radionuclides that contribute to dose at Furnace Creek are Tc-99 and I-129 (Figure 3-3). The 

contribution from Tc-99 begins to decrease at about 364,000 years after repository closure due 

to its shorter half-life than I-129 (~200,000 years compared to 15.7 million years). Under the 

lower flow rates associated with the present-day climate, no radiological contaminants reach the 

Furnace Creek area before 10,000 years after repository closure. Estimated peak annual doses 

for the one million-year period are slightly greater for the present-day climate state because 

there is less dilution of the contaminants in the groundwater. Although the contaminants arrive 

at Furnace Creek earlier in the cooler/wetter climate state, the peak dose is lower due to the 

lower groundwater contaminant concentrations. The estimated peak annual doses are much 

lower than the NRC annual dose standards for a Yucca Mountain repository in 10 CFR Part 63 

{15 mrem [0.15 mSv] for the first 10,000 years, and 100 mrem [1 mSv] for one million years, 

after permanent closure}. 

Furnace Creek Nonradiological Contaminants 

Peak daily intakes of the nonradiological contaminant Mo at Furnace Creek are given in 

Table 3-12 for both climate states. As discussed in the previous sections on impacts on the 

aquifer and soil, Mo is the only nonradiological contaminant present in groundwater discharging 

from springs at Furnace Creek, and only at the one million year period. The calculated peak 

daily intake at Furnace Creek correlates with the maximum peak concentration in groundwater 

and soil approximately 58,000 years after repository closure for the present-day climate state 

and is 1.3 × 10−3

 mg/kg body-weight/day (as with the groundwater, the maximum for the 

cooler/wetter climate occurs slightly earlier and is a lower value). Human health impacts of the 

nonradiological contaminants are assessed by comparing daily intakes with EPA’s Oral 

Reference Dose standard (EPA, 1999a,b; 1997a,b; 1994). For ingestion of potentially 

contaminated water, daily intake is estimated for a 70-kg person drinking 2 L [0.53 gal] of 

water daily. The estimated maximum value of daily intake is lower than the EPA Oral 

Reference Dose. 

Middle Basin Radiological Contaminants 

Peak annual dose estimates for Middle Basin are given in Table 3-13 for both climate states. 

As at the Furnace Creek area, the radiological contaminants that contribute to estimated dose in 

Middle Basin of Death Valley are limited to those elements whose transport in groundwater is 

not delayed due to sorption processes. As groundwater flows to Middle Basin and evaporates, 

these elements are incorporated into the resulting evaporite mineral deposits. Again, Tc-99 

and I-129 are the primary contributors to dose (Figure 3-4). As at the Furnace Creek area 

(Figure 3-3), the contribution from Tc-99 decreases beginning at about 364,000 years after 

repository closure due to its shorter half-life than that of I-129. Similar to the results at the 

Furnace Creek area, dose estimates are greatest at one million years under the present-day 

climate scenario because of the dilution of the radiological contaminants in the larger 

groundwater flow volume under the cooler/wetter climate state, although the contaminants 

arrive sooner under the cooler/wetter conditions. 
3-27 

Table 3-11. Peak Annual Dose Estimates for the Furnace Creek Area 

Peak Annual Dose (mrem/yr)* 

10,000 years 1 million years 

Present-day Climate 0.0 0.16

Cooler/Wetter Climate 0.015 0.042 *

1.0 mrem/yr = 0.01 mSv/yr

Figure 3-3. Dose History for Selected Radionuclides and Total Dose at the Furnace 

Creek Area for the Present-Day (Top) and the Cooler/Wetter (Bottom) 

Climate States.
3-28 

Table 3-12. Peak Daily Intake for Mo at Furnace Creek 

Peak Daily Intake* 

(mg/kg body-weight/day) 

Present-Day 

Climate 

Cooler/Wetter 

Climate Oral Reference Dose 

Mo 1.3 × 10−3 3.8 × 10−4 5.0 × 10−3

*Calculated peak daily intake for Mo occurs at 58,000 years after repository closure for the present-day climate, and 

at 20,000 years for the cooler/wetter climate. 

Mo = molybdenum 

The peak annual dose estimates for Middle Basin are lower for both climate states than those 

for the Furnace Creek area. The low dose estimates are primarily due to the absence of a 

drinking water pathway at Middle Basin, given the high salinity of any standing water on the 

wet playa. As with the Furnace Creek results, estimated peak annual doses are much 

lower than the NRC dose standards for a Yucca Mountain repository in 10 CFR Part 63 

{15 mrem [0.15 mSv] for the first 10,000 years, and 100 mrem [1 mSv] for one million years, 

after permanent closure}. 

Middle Basin Nonradiological Contaminants 

Peak daily intakes of nonradiological contaminants at Middle Basin are given in Table 3-14 for 

both climate states. As at Furnace Creek, Mo is the only nonradiological contaminant present in 

groundwater discharging at Middle Basin. At this location, Mo is present only at one million 

years under the present-day climate state, but is present both at 10,000 and one million years 

under the cooler/wetter climate state. 

Human health impacts of nonradiological contaminants are assessed by comparing daily 

intakes with EPA’s Oral Reference Dose standard (EPA, 1999a,b; 1997a,b; 1994). At this 

location, the principal pathway is ingestion and inhalation of contaminated soil, as the water at 

this location is not potable. As previously noted, the peak concentration for molybdenum occurs 

approximately 58,000 years after repository closure for the present-day climate (the peak is 

lower for the cooler/wetter climate, but occurs earlier). The peak Mo daily intake at Middle 

Basin is estimated to be 3 × 10−4

 mg/kg body weight/day. The estimated values of daily intake 

in Table 3-14 and the peak value are both lower than the EPA Oral Reference Dose. 

Based on the above, estimated doses from radiological contaminants at Furnace Creek and 

Middle Basin would be very low for both climate states {less than 1 mrem/year [0.01 mSv/yr]}, 

and the peak daily intakes of nonradiological contaminants would also be very low (below the 

EPA Oral Reference Dose). Therefore, the NRC staff finds that impacts to public health from 

radiological and nonradiological contaminants associated with natural groundwater discharges 

at Furnace Creek and Middle Basin of Death Valley would be SMALL. 

Table 3-13. Peak Annual Dose Estimates for Middle Basin 

Peak Annual Dose (mrem/yr)* 

10,000 years 1 million years 

Present-day Climate 0.0 0.16

Cooler/Wetter Climate 0.015 0.042

*1.0 mrem/yr = 0.01 mSv/yr
3-29 

Figure 3-4. Dose History for Selected Radionuclides and Total Dose at Middle Basin for 

the Present-Day (Top) and Cooler/Wetter (Bottom) Climate States
3-30 

Table 3-14. Peak Daily Intake for Mo at Middle Basin 

Peak Daily Intake*

(mg/kg body-weight/day) 

Present-Day 

Climate 

Cooler/Wetter 

Climate Oral Reference Dose 

Mo 3.0 × 10−4

 1.8 × 10−5 5.0 × 10−3

*

Calculated peak daily intake for Mo occurs at 58,000 years after repository closure for the present-day climate, and 

at 20,000 years for the cooler/wetter climate. 

Mo = molybdenum 

3.1.2.3 Alkali Flat 

Alkali Flat is located approximately 45 km [28 mi] from the postclosure compliance location, or 

63 km [39 mi] from the proposed repository. The groundwater at Alkali Flat is a combination of 

groundwater flowing from Ash Meadows and groundwater from western Amargosa Desert and 

Fortymile Wash. As discussed in Section 2.2.2, under scenarios in which there is no pumping in 

the Amargosa Farms area, groundwater modeling indicates that the majority of contaminants 

transported from Yucca Mountain will be discharged in Middle Basin, and to a lesser extent, at 

Furnace Creek (or the State Line Deposits area in a wetter climate) prior to reaching 

Middle Basin (Belcher and Sweetkind, 2010; DOE, 2014a). DVRFS modeling indicated that 

only a small fraction of contaminants could be directed southward toward the Alkali Flat area 

(Belcher and Sweetkind, 2010; DOE, 2014a). 

There are no people living at Alkali Flat. The water composition is highly variable, from saline to 

relatively dilute (low TDS), with the more-dilute water found in the small springs on the upstream 

side of the playa. Due to the lack of residents and the very limited amount of potable water at 

the site, potential exposure pathways are limited to inhalation and exposure to resuspended 

dust from evaporites in which radiological and nonradiological contaminants may have 

precipitated from evaporation of groundwater discharge. 

Estimates of groundwater, soil, and surface discharge mass and concentration at Alkali Flat 

were not explicitly calculated for this supplement, as the impacts can be estimated from the 

estimates for the other, more-likely discharge areas. Alkali Flat is similar to Middle Basin in its 

dominantly playa environment, and in its inhospitable conditions and lack of habitation. But 

Alkali Flat is more distant from present population centers, and is less likely to have visitors or 

temporary occupants. The exposure pathways and biological dose conversion factors used for 

a playa at Middle Basin are therefore applicable (and conservative) for Alkali Flat. The 

fraction of the contaminant plume reaching Alkali Flat is expected to be very small (less than 

one percent of the potential release reaching the postclosure compliance location, based on 

DVRFS modeling). Thus, the results in Section 3.1.2.2 for release of the entire plume at 

Middle Basin are likely to overestimate the contaminants in the groundwater or accumulated in 

soil at Alkali Flat (even though the transport path is marginally shorter from the repository to 

Alkali Flat). For these reasons, the NRC staff finds that the impacts at Alkali Flat would be a 

small fraction of those calculated for Middle Basin under both climate states, which were found 

to be SMALL, above. Therefore, the aquifer environment, soil, and public health (radiation dose 

and body intake of chemicals) impacts for Alkali Flat would be SMALL. 

3.2 Ecological Impacts 

The NRC staff evaluated the potential for ecological impacts from radionuclides and chemical 

constituents at the potential locations for surface discharges of groundwater to the environment 
3-31 

by considering the estimated radiation doses to humans (as a general indicator of the 

magnitude of radiological exposure), the concentrations of chemical constituents in various 

environmental media, and available information about how nonhuman biota could be impacted 

by radiological and chemical exposures. Relatively few studies have established impact levels 

for nonhuman biota exposed to radionuclides. Data on the impacts of nonradiological 

contaminants are more abundant but still limited (Hinck et al., 2010; Poston et al., 2011; 

Sample et al., 1996). Most available data on both radiological and nonradiological contaminants 

are from laboratory animal toxicity studies that do not address chronic exposure or 

ecosystem-level impacts. Nonhuman biota exhibit varying levels of sensitivity to radiation and 

chemical exposures (Poston et al., 2011; Sample et al., 1996), although some biological 

receptors are potentially more or less susceptible than others. For example, the more highly 

developed phylogenetic classes of organisms (plants and animals) tend to be more susceptible 

to radiation effects than less developed ones (Poston et al., 2011). 

Given the very low doses estimated for Amargosa Farms, the State Line Deposits/Franklin Well 

area, and for Furnace Creek/Middle Basin in the previous sections, the NRC did not specifically 

calculate doses to nonhuman biota from radiological contaminants at these locations. The NRC 

staff considers it unlikely that nonhuman biota would receive doses significantly greater than the 

human dose estimates when the latter are a small fraction of the background exposure level. 

Based on this analysis, the NRC staff concludes that the potential for ecological impacts from 

radiological contaminants at these locations would be SMALL. 

The NRC staff evaluated the potential for nonhuman biota to be exposed to potentially harmful 

levels of chemical constituents at Amargosa Farms, State Line Deposits/Franklin Well area, and 

Furnace Creek/Middle Basin based on the aquifer and soil concentrations in Sections 3.1.1 and 

3.1.2 for present-day and cooler/wetter climates and for both the 10,000 year and one-millionyear time-frames. Comparisons of the estimated groundwater and soil concentrations for the 

nonradiological contaminants to ecological impact concentrations are given for the three areas 

in Tables 3-15, 3-16, and 3-17. The water and soil concentrations shown in these tables are for 

the climate state showing the greatest concentration over the one million year time period for 

each area. Two approaches are used in Section 3.1.2.1 to estimate contaminant concentrations 

in surficial material: the evaporite model for playas and the salt marsh model for areas near and 

downstream from springs and pools. The values in Table 3-16 are derived from the salt marsh 

model because biota would dominantly be associated with springs and pools; and would be 

sparse on the saline playas. 

The ecological impact values shown in Tables 3-15, 3-16, and 3-17 are derived from various 

data, depending on the applicability and availability of information and considering the wildlife 

that are representative of the region. Water concentration values are based on EPA aquatic life 

criteria (EPA, 2014) (available only for Ni) or the reported ranges of adverse ecological effect 

concentrations in scientific literature compilations. The threshold range for U in water is the 

range of reported guideline values in Hinck et al. (2010). The ranges for Mo and V in water are 

from Sample et al. (1996). The ecological impact values for soil concentrations of Ni and V are 

the EPA ecological soil screening levels (EPA, 2007; 2005). 

These EPA levels were developed to support screening analyses to identify potential ecological 

concerns at Comprehensive Environmental Response, Compensation, and Liability Act 

(CERCLA) sites that may need further, more detailed, evaluation (e.g., ecological risk 

assessment). EPA stated that it expected that any federal, state, tribal or private environmental 

assessment could use the values to screen soil contaminants (EPA, 2003). The soil range for 

Mo is based on dietary concentrations where adverse effects have been observed in the most 
3-32 

Table 3-15. Comparison of Estimated Groundwater and Soil Concentrations*

 of 

Contaminants at Amargosa Farms With Ecological Impact 

Concentrations (ppm) 

Constituent 

Estimated Water 

Concentration 

Ecological 

Impact 

Concentration†

Estimated Soil 

Concentration 

Ecological 

Impact 

Concentration†

Mo 7.3 × 10−3 0.6–107 0.08 100–500 

Ni 0.02 0.052 14.0 38–280 

V 6.4 × 10−9 0.835–200 4.5 × 10−4 7.8–280 

U (all isotopes) 1.9 × 10−4‡ 0.0026–69 0.026 5–200 

*Concentrations in ppm (mg/L or mg/kg) are peak values that consider both the present-day and cooler/wetter 

climates. 

†

The ecological impact values are from various sources, based on applicability and availability of information 

including EPA (2014; 2007; 2005), Hinck et al. (2010), and Eisler (1989), as described in Section 3.2. ‡

Concentration in ppm (mg/L) calculated from total uranium activity per liter from Table 3-2. 

Mo = molybdenum, Ni = nickel, V = vanadium, U = uranium

Table 3-16. Comparison of Estimated Groundwater and Soil Concentrations*

 of 

Contaminants at State Line/Franklin Well With Ecological Impact 

Concentrations (ppm)

Constituent 

Estimated Water 

Concentration†

Ecological 

Impact 

Concentration‡

Estimated Soil 

Concentration§

Ecological 

Impact 

Concentration‡

Mo <7.3 × 10−3 0.6–107 0.011 100–500 

Ni <0.02 0.052 3.4 38–280 

V <6.4 × 10−9 0.835–200 3.0 × 10−3 7.8–280 

U (all isotopes) <1.9 × 10−4║ 0.0026–69 0.007 5–200 

*Concentrations in ppm (mg/L or mg/kg) are peak values that consider both the present-day and cooler/wetter 

climates. 

†

Estimated aquifer concentration at State Line/Franklin Well is down gradient from Amargosa Farms and would, 

therefore, be less than the Amargosa Farms estimate. ‡

Sources as in Table 3-15. 

§

Soil concentrations are based on values from the irrigation recycling model approach, Section 3.1.2.1 ║

Concentration of U in water calculated from total uranium activity per liter from Table 3-2. 

Mo = molybdenum, Ni = nickel, V = vanadium, U = uranium

Table 3-17. Comparison of Estimated Groundwater and Soil Concentrations*

 of 

Contaminants at Death Valley Middle Basin† With Ecological Impact 

Concentrations (ppm) 

Constituent 

Estimated Water 

Concentration 

Ecological 

Impact 

Concentration‡

Estimated Soil 

Concentration 

Ecological 

Impact 

Concentration‡

Mo 0.05 0.6–107 208 100–500 

Ni 0.0 0.052 0.0 38–280 

V 0.0 0.835–200 0.0 7.8–280 

U (all isotopes) 0.0 0.0026–69 0.0 5–200 

*Concentrations in ppm (mg/L or mg/kg) are peak values that consider both the present-day and cooler/wetter 

climates 

†

Furnace Creek groundwater concentrations would be similar, but there would be no accumulation of constituents in 

soil, as described in Section 3.1.2.1. 

‡

Sources as in Table 3-15. 

Mo = molybdenum, Ni = nickel, V = vanadium, U = uranium 
3-33 

sensitive applicable organisms (rabbits and birds) (Eisler, 1989). This dietary concentration is 

compared with the estimated soil concentration, based on the assumption that the plants 

consumed by the organisms would be in equilibrium with the estimated soil concentration. 

The U range is the soil concentration-based guidance levels reported by Hinck et al., 2010). 

The results of the NRC staff’s comparison of the estimated aquifer and soil concentrations with 

the ecological impact concentrations are provided in Tables 3-15 through 3-17. The estimated 

water and soil concentrations of Mo, Ni, V, and U at Amargosa Farms, the State Line 

Deposits/Franklin Well area, and at Furnace Creek/Middle Basin are generally below the 

ecological impact concentrations. The only exception is for Mo in the evaporite soil at 

Middle Basin. As previously discussed, this conservative value is for a highly saline soil which 

can support only sparse, if any, vegetation, and thus could not be the principal support for 

nonhuman biota. Therefore, the NRC staff concludes that environmental impacts to nonhuman 

biota from these chemical constituents would be SMALL. 

Because the NRC staff finds that only a very small fraction of the contaminants are expected to 

reach Alkali Flat (Section 3.1.2.3), impacts to nonhuman biota at Alkali Flat would be much less 

than at the areas evaluated above. In addition, Alkali Flat is expected to remain dominantly a 

playa environment with sparse amounts of salt-tolerant vegetation growing in highly saline 

surficial material. Based on this analysis, the NRC staff concludes that the potential for 

ecological impacts from radiological and nonradiological contaminants at Alkali Flat would 

be SMALL. 

In summary, based on the analyses in this section, the NRC staff concludes that the potential 

for ecological impacts from radiological and nonradiological contaminants at all of the surface 

discharge locations would be SMALL. 

3.3 Historic and Cultural Resources 

As stated in Section 2.3.2, historic and cultural resources may be located in or around current 

surface discharge areas, described in Section 2.3.3, or in paleospring discharge areas 

(and potential future discharge locations), described in Section 2.3.4. This section briefly 

describes DOE’s analysis of impacts on cultural resources in its EISs, summarizes the NRC 

staff conclusions in its 2008 ADR, describes the scope of DOE’s programmatic agreement with 

the Nevada State Historic Preservation Office (SHPO) and the Advisory Council on Historic 

Preservation (ACHP) under the National Historic Preservation Act (NHPA) (see Section 3.3.3), 

describes more recent work by DOE to evaluate impacts on historic and cultural resources, 

and provides the NRC staff’s conclusions regarding impacts to historic and cultural resources at 

surface discharge locations. 

3.3.1 Assessments in the DOE Environmental Impact Statements 

DOE’s historic and cultural resource analyses in its EISs for the proposed repository at 

Yucca Mountain focused on the repository site and the surrounding controlled area. 

Section 4.1.5 of the 2002 EIS contains DOE’s evaluation of the potential environmental impacts 

of the proposed repository on historic and cultural resources. DOE updated its historic and 

cultural resources impact assessment in Sections 4.1.5 and 4.3.2.5 of the 2008 SEIS. 

Section 4.1.5 of the 2008 SEIS provides an update to the expected historic and cultural 

resources impacts, accounting for new information and an expanded region of influence, 

including land that DOE had proposed for an access road from U.S. Highway 95 and land where 

DOE would construct offsite facilities. Section 4.3.2.5 of the 2008 SEIS assesses the potential 
3-34 

historic and cultural resource impacts of proposed infrastructure improvements, such as the 

construction or replacement of roads, the installation of transmission lines, and various 

on-site improvements.

In its 2002 EIS, DOE also noted that the “Native American view of resource management and 

preservation is holistic in its definition of ‘cultural resource,’ incorporating all elements of the 

natural and physical environment in an interrelated context. Moreover, this view includes little or 

no differentiation between types of impacts (direct versus indirect), but considers all impacts to 

be adverse and immune to mitigation.” DOE also summarized the results of studies that 

delineated several Native American sites, areas, and resources in DOE’s region of influence for 

cultural resources. DOE further stated that it would continue its Native American Interaction 

Program throughout the construction, operation, closure, and monitoring of the repository 

(DOE, 2002; Section 4.1.5.2). 

3.3.2 Assessment in the NRC Staff’s Adoption Determination Report (2008) 

Section 3.2.1.4.1 of the ADR notes that DOE identified and described in its EISs the status of its 

NHPA consultation processes. The ADR states that some of the bases for EIS impact analyses 

and proposed mitigation measures include the anticipated results of these processes or other 

investigations that were ongoing, and that DOE committed in various sections of its EISs 

to resolving these ongoing activities. The ADR highlights two activities relevant to historic and 

cultural resources: 

 DOE had been consulting with the Nevada SHPO and the ACHP to develop a 

programmatic agreement for the proposed repository. 

 DOE indicated its intent to have continuing discussions with Native American tribes 

through its Native American Interaction Program and proposed establishing a “mitigation 

advisory board” to explore ways to address concerns about adverse impacts. 

The ADR notes that, as indicated in NUREG–1748 (NRC, 2003; Section 5.1.4), an EIS should 

describe the current status of the required permit applications and consultations, but it is not 

necessary that all permitting and consultation activities be completed before publication of the 

final EIS. Additionally, the ADR notes that the Council on Environmental Quality (CEQ) 

regulations at 40 CFR 1502.22 state that an EIS may document incomplete or unavailable 

information provided the EIS clearly indicates such information is lacking. The NRC staff 

concluded in the ADR that the discussions of these ongoing activities in the DOE EISs meet 

NRC regulations and are consistent with NRC guidance. 

The ADR also addresses how DOE assessed the impacts of the proposed repository on historic 

and cultural resources. As discussed further in the ADR, the two main components of DOE’s 

analysis were (i) a description of DOE’s efforts to assess effects on specific historic and cultural 

resources and (ii) a discussion of Native American viewpoints, which DOE characterizes as an 

opposing viewpoint. The ADR also notes that in its EISs, DOE further indicates its intent to 

continue its Native American Interaction Program to comply with the various laws that may 

affect Native American cultural practices, and to establish one or more mitigation advisory 

boards to address concerns about adverse impacts. The NRC staff concluded in the ADR that 

the consideration of Native American concerns and the impacts assessed on historic and 

cultural resources in the DOE EISs is adequate under the National Environmental Policy Act 

(NEPA). 
3-35 

3.3.3 DOE’s Programmatic Agreement (2009) 

As discussed in Section 2.3.2, in 2009 DOE finalized a programmatic agreement with the ACHP 

and the Nevada SHPO concerning the development of a repository at Yucca Mountain 

(DOE, 2009b). The area covered by the agreement “includes all site activities conducted by 

[DOE] and its contractors for the licensing and development of Yucca Mountain as a repository 

for disposal of spent nuclear fuel and high-level radioactive waste that have the potential to 

affect historic properties, and that are located within the boundaries of the Yucca Mountain 

Project Operator-Controlled Area... In the event the DOE is granted the proposed land 

withdrawal area depicted in Figure 1, this Agreement will be amended to expand the 

[Yucca Mountain Project Operator-Controlled Area]” to include the land withdrawal area 

(DOE, 2009a; Section A.1). The programmatic agreement further states that impacts from 

activities that support the repository, but which occur outside of the Operator-Controlled Area, 

are outside the scope of the agreement and would need to be considered separately. The 

agreement states that DOE would consult with the SHPO and appropriate State agencies, as 

necessary, regarding compliance with any applicable State and Federal laws or regulations 

(DOE, 2009a; Section A.1 and A.2). The agreement also states that should the NRC grant a 

construction authorization for the proposed repository, the NRC may use the agreement to fulfill 

its obligations under Section 106 of the NHPA. 

3.3.4 Additional DOE Analysis (2014) 

DOE’s 2014 analysis of the potential impacts of the repository on groundwater and on surface 

discharges of groundwater (DOE, 2014a) includes a discussion of Native American concerns 

and provides an assessment of the potential impacts on Furnace Creek area residents of using 

and consuming groundwater that could contain contaminants from the repository. This 

assessment does not provide an accounting of any historic and cultural resources that may be 

present at or near surface discharge locations. 

3.3.5 NRC Staff Evaluation 

The NRC staff concluded in its ADR that DOE adequately addressed the potential impacts on 

historic and cultural resources in its EISs, given DOE’s defined region of influence and given 

that some consultation processes were still ongoing at the time the final 2008 SEIS was 

published. Based on the region of influence DOE described in its EISs (DOE, 2008a; 2002), the 

NRC staff concludes that the affected environments considered in this supplement are outside 

the region DOE evaluated in its EISs’ assessments of these impacts, and that the NRC staff 

found acceptable in its ADR. The NRC staff acknowledges that DOE has developed a 

programmatic agreement to specifically address impacts on historic properties under the NHPA. 

However, the NRC staff notes that the agreement scope does not include areas outside the 

Operator-Controlled Area and that the agreement states that any impacts outside this area 

would need to be addressed separately. In addition, the DOE programmatic agreement focuses 

on proposed activities within the state of Nevada, and some of the affected areas identified in 

this supplement (and in DOE, 2014a) are in California. Thus, the NRC staff concludes that DOE 

would need to assess whether further consultation and investigation are necessary to account 

for potential impacts on cultural resources that may be located in areas where groundwater 

discharges to the surface. 
3-36 

3.4 Environmental Justice 

Environmental justice refers to a Federal policy implemented to ensure that minority, 

low-income, and tribal communities historically excluded from environmental decision-making 

are given equal opportunities to participate in decision-making processes. This section 

discusses potential environmental justice issues related to the evaluations in this supplement for 

impacts on groundwater and the surface discharge of groundwater. Specifically, this section 

summarizes the environmental justice analysis in DOE’s EISs, describes more recent work by 

DOE to evaluate environmental justice impacts, and provides the NRC staff’s analysis and 

conclusions regarding environmental justice impacts from groundwater or surface discharges 

of groundwater. 

Under Executive Order 12898 (59 FR 7629), Federal agencies are responsible for identifying 

and addressing potentially disproportionately high and adverse human health and 

environmental impacts on minority and low-income populations. In 2004, the NRC issued a 

Policy Statement on the Treatment of Environmental Justice Matters in NRC Regulatory and 

Licensing Actions (69 FR 52040), which states that “The Commission is committed to the 

general goals set forth in Executive Order 12898, and strives to meet those goals as part of its 

National Environmental Policy Act (NEPA) review process.” 

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 risks of

impacts 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. 

3.4.1 Assessments in DOE’s Environmental Impact Statements 

In its EISs, DOE provided an analysis of environmental justice impacts but did not identify 

groundwater as a resource area for which potential environmental justice impacts could occur. 

Because DOE did not provide an environmental justice analysis for impacts from groundwater 

or from surface discharges of groundwater, the NRC staff concludes that, consistent with the 

finding in the ADR with regard to the need for further supplementation, this discussion in the 

EISs is incomplete. The NRC staff’s assessment is provided in the next section. 

3.4.2 NRC Staff Assessment 

This section assesses the potential for disproportionately high and adverse human health or 

environmental effects on minority and low-income populations that could result from 

groundwater containing contaminants from the repository. As stated in Section 2.1.1, the NRC 

staff incorporates by reference its SER assessment and DOE’s license application description of 

regional demography. For this analysis, the affected area consists of population centers located 

along the groundwater flow path from Yucca Mountain. Section 2.1.1 describes population 

centers within an 84-km [52-mi] radius of Yucca Mountain, comprising parts of Clark, 

Esmeralda, Lincoln, and Nye Counties in Nevada, and Inyo County in California. Within that 

radius, there are two population centers that the NRC staff has determined are located along 

the groundwater flow path from Yucca Mountain. The potentially-affected population centers 

are the town of Amargosa Valley in Nye County, Nevada, and Death Valley National Park in 
3-37 

Inyo County, California (NRC, 2015a; Section 2.1.1.1.3.2., Population Centers). The NRC 

staff’s analysis of potential environmental justice impacts at these two locations is 

provided below. 

Impacts on Minority and Low-Income Populations in the Amargosa Valley Area 

The Amargosa Valley Census County Division (CCD) is a census area of Nye County, Nevada, 

located along the groundwater flow path from Yucca Mountain. Table 3-18 provides a summary 

of minority and low-income populations for this group. 

NRC guidance states that minority and low-income populations with differences greater than 

20 percentage points higher than the state or county percentages, or that exceed 50 percent of 

the census (typically at the block level) group, may be considered to be significant (NRC, 2003). 

Following this guidance, the NRC staff considers the minority population in the Amargosa Valley 

CCD to be a significant environmental justice population (NRC, 2003). The NRC staff, 

therefore, evaluated whether the minority and low-income populations could experience 

disproportionately high and adverse human health and environmental effects from groundwater 

impacts. The groundwater impacts in the town of Amargosa Valley (which includes the 

Amargosa Farms area) would be from pumping potentially contaminated groundwater used 

primarily for irrigation (Section 2.3). Section 3.1.1 describes the potential groundwater impacts 

in Amargosa Farms. Amargosa Farms pumps groundwater for irrigation and for its commercial 

and domestic water supply. The dose pathways for a resident of Amargosa Farms are external 

(body) exposure, inhalation, and ingestion of water, crops, animal products, fish, and soil. 

Section 3.1.1 describes the concentration of contaminants in the groundwater at the Amargosa 

Farms area (see Table 3-2), the concentration of contaminants in soils in the Amargosa Farms 

area due to irrigation (see Table 3-3), and the dose and body intake values for radiological 

contaminants (see Table 3-4) and nonradiological contaminants (see Table 3-5). 

In Section 3.1.1, the NRC staff finds that both for the present-day and wetter climates: (i) the 

impacts at Amargosa Farms from radiological and nonradiological contaminants to the aquifer 

environment would be SMALL; (ii) the impacts on soils at Amargosa Farms would be SMALL; 

and (iii) the impacts on public health at Amargosa Farms would be SMALL. Further, the peak 

dose of 1.3 mrem/yr [0.013 mSv/yr] in Table 3-4 is substantially smaller that the dose from 

natural background levels of approximately 300 mrem/yr [3.0 mSv/yr] (including radon) for 

Amargosa Valley. 

Based on its conclusions in Section 3.1.1 concerning impacts on groundwater, soils, and public 

health, the NRC staff finds no environmental pathway that would affect minority or low-income 

populations differently from other segments of the general population. Therefore, the NRC staff 

concludes that no disproportionately high and adverse health or environmental impacts would 

occur to minority or low-income segments of the population in the Amargosa Valley area. 

Impacts on Minority and Low-Income Populations at Death Valley National Park 

The Death Valley CCD, located in Inyo County, California, is a census population located along 

the groundwater flow path from Yucca Mountain, and includes the Furnace Creek springs area 

in Death Valley National Park. Table 3-19 provides a summary of minority and low-income 

populations for this group. 

Based upon census data, the NRC staff does not consider the Death Valley CCD to be a 

significant environmental justice community (NRC, 2003). However, as noted in Chapter 2, the 
3-38 

Table 3-19. 2010 Minority Populations and 2010-2014 5-Year Poverty Estimates for the 

Death Valley Area 

Death Valley 

Census County 

Division Inyo County California 

Percent Minority 

(Including Hispanic and Latino Ethnicity)* 19 34 60 

Percent of Persons Below the Poverty 

Level†

 23 14 16 

*Minority population based on 2010 U.S. Census. Minority population includes persons of Hispanic, Latino, or 

Spanish origin who are considered an ethnic minority and may be of any race (USCB, 2010). †

Population below poverty level based on 2010-2014 American Community Survey 5-year estimates. 

Source: U.S. Census Bureau American Fact Finder http://factfinder.census.gov/faces/nav/jsf/pages/index.xhtml 

(accessed April 19, 2016) 

Percentages are rounded to the nearest whole number

population in the Death Valley CCD includes the Timbisha Shoshone Tribe community located 

on a 314-acre [1.27-km2] parcel of land in the Furnace Creek area. The Tribe has federally 

appropriated rights to 92 acre-ft/year [0.113 million m3/yr] of surface and groundwater. The 

springs in the Furnace Creek area, including the Furnace Creek, Texas, Travertine, and Salt 

Springs, are of traditional and cultural importance to the Tribe (DOE, 2014a). Because of the 

unique characteristics of the Timbisha Shoshone Tribe community within the Death Valley CCD, 

the NRC staff evaluated whether disproportionately high and adverse human health and 

environmental effects from groundwater impacts would affect the community. As discussed 

below, the NRC staff finds that the Timbisha Shoshone Tribe would not experience 

disproportionately high and adverse human health or environmental effects from the 

proposed repository. 

Section 3.1.2 describes the impacts of surface discharges, assuming no pumping at 

Amargosa Farms, for both the present-day and cooler/wetter climate states. The assumption of 

no pumping at Amargosa Farms models the maximum quantity of groundwater, and potential 

contaminants, to discharge at surface locations in Death Valley (as discussed in Chapter 2; with 

present pumping rates at Amargosa farms, no contaminants from the repository would reach 

Death Valley). The sites where discharges of radiological and nonradiological contaminants 

Table 3-18. 2010 Minority Populations and 2010-2014 5-Year Poverty Estimates for the 

Amargosa Valley Area 

Amargosa Valley 

Census County 

Division 

Nye County Nevada 

Percent Minority 

(Including Hispanic and Latino Ethnicity)* 50 21 46 

Percent of Persons Below the Poverty 

Level†

 31 19 16 

*Minority population based on 2010 U.S. Census. Minority population includes persons of Hispanic, Latino, or 

Spanish origin who are considered an ethnic minority and may be of any race (USCB, 2010). †

Population below poverty level based on 2010-2014 American Community Survey 5-year estimates. 

Source: U.S. Census Bureau American Fact Finder <http://factfinder.census.gov/faces/nav/jsf/pages/index.xhtml> 

(accessed April 19, 2016) 

Percentages are rounded to the nearest whole number. 
3-39 

could occur are springs at the State Line Deposits/Franklin Well area (under a wetter climate 

only), springs at Furnace Creek, and the playa/salt pan at Middle Basin of Death Valley. The 

NRC staff estimated the peak impact at these two areas by conservatively assuming that the 

entire contaminant plume would discharge at each location. Biosphere dose conversion factors 

for these areas are based on exposures to full-time residents. As stated in Section 3.1.2.2, the 

dose pathways for a resident in these areas include external exposure, inhalation of 

soil/evaporite particulates and water vapor from evaporative coolers, and ingestion of water and 

soil/evaporite particulates. The NRC staff did not evaluate the ingestion of crops, animal 

products, and fish as pathways because there is little current agricultural production near the 

Furnace Creek area, and the NRC staff does not expect that wet playas would be used for 

agriculture. Likewise, for the Middle Basin wet playa, the NRC staff did not include the ingestion 

of water and exposure from evaporative coolers as pathways because the saline content of the 

water is unsuitable for such uses. Even in wetter climates, the wet playa water would be 

unsuitable for use as drinking water or in agriculture. 

In Section 3.1.2.2, the NRC staff concludes that for the Furnace Creek area and for 

Middle Basin for the present-day and wetter climates: (i) the impact to the accessible 

environment for those locations would be SMALL; (ii) the soil impacts associated with 

groundwater discharges at Furnace Creek and Middle Basin would be SMALL; and (iii) the 

potential public health impacts from radiological and nonradiological contaminants associated 

with natural groundwater discharges at Furnace Creek and Middle Basin would be SMALL. 

In Section 3.5 of its analysis of groundwater impacts (DOE, 2014a), DOE provided a discussion 

of potential impacts on members of the Timbisha Shoshone Tribe. This analysis is consistent 

with the NRC staff’s conclusion. Based on its analysis, DOE states (DOE, 2014a; p.3-28): 

DOE has identified no high and adverse potential impacts to members of the 

general public associated with exposure to contaminants that may occur in 

groundwater following closure of a repository at Yucca Mountain. Further, DOE 

has not identified subsections of the population, including minority or low-income 

populations that would receive disproportionate impacts. Likewise, DOE has 

identified no unique exposure pathways that would expose minority or 

low-income populations to disproportionately high and adverse impacts. The 

Department acknowledges the sensitivities and cultural practices of the Timbisha 

Shoshone Tribe concerning the use and purity of springs in the [Furnace] Creek 

area; however, the information included in this Analysis of Postclosure 

Groundwater Impacts demonstrates that the potential concentrations of 

contaminants in those springs would be so low that there would be virtually no 

potential health effects associated with the use of those springs. Thus, this 

document supports the Department’s previous conclusion that no 

disproportionately high and adverse impacts would result from a repository. 

Based on its conclusions in Section 3.1.2 concerning impacts on groundwater, soils, and 

public health, the NRC staff finds no environmental pathway that would physiologically affect 

minority or low-income populations differently from other segments of the general population; 

therefore, the NRC staff concludes that no disproportionately high and adverse health or 

environmental impacts would occur to minority or low-income segments of the population in 

the Death Valley area. 
3-40 

3.4.3 NRC Staff Conclusion 

The NRC staff acknowledges the sensitivities and cultural practices of the Timbisha Shoshone 

Tribe concerning the use and purity of springs in the Furnace Creek area. Based on the 

analysis above, the NRC staff determines that there would be no disproportionately high and 

adverse human health or environmental effects from uses or discharges of groundwater flowing 

from the repository on minority or low-income segments of the populations in the 

Amargosa Valley area and in Death Valley National Park. 

3.5 Summary 

In its 2008 SEIS, DOE determined that the waterborne pathway (groundwater flow to discharge 

locations downstream) would dominate potential postclosure impacts of a repository at 

Yucca Mountain. DOE found that its estimated mean annual individual dose at the postclosure 

compliance location was a small fraction of the 15 mrem/yr [0.15 mSv/yr] standard in 

40 CFR Part 197 (for the first 10,000 years after closure). Similarly, DOE found that the 

estimated annual dose for the one–million-year period was a small fraction of the annual limit. 

DOE also found that significant human impacts from chemicals and anticipated adverse impacts 

to biological resources would be unlikely. 

In this supplement, the NRC staff finds that the impacts to groundwater and from surface 

discharges of groundwater beyond the postclosure compliance location are SMALL. 

The peak radiological dose from estimates for all locations evaluated in this supplement is 

1.3 mrem/yr [0.013 mSv/yr], which occurs in the Amargosa Farms area for Analysis Case 1 

(pumping). The NRC staff finds that the calculated radiological doses are SMALL because they 

are much lower than the NRC annual dose standards for a Yucca Mountain repository in 

10 CFR Part 63 {15 mrem [0.15 mSv] for the first 10,000 years, and 100 mrem [1 mSv] for one 

million years, after permanent closure}. The peak dose estimates considered uncertainty in 

climate and pumping rates. Based on conservative assumptions about the potential for health 

effects from exposure to low doses of radiation, the estimated radiation dose is expected to 

contribute a negligible increase in the risk of cancer or severe hereditary effects in the 

potentially exposed population. 

Impacts to all of the affected environments beyond the postclosure compliance location from 

nonradiological (chemicals) material from the repository were also found to be SMALL, as were 

radiological and nonradiological ecological impacts (Section 3.2). 
4-1 

4 CUMULATIVE IMPACTS 

Chapter 3 of this supplement contains the U.S. Nuclear Regulatory Commission (NRC) staff’s 

assessment of impacts on groundwater and on surface discharges of groundwater. In this 

chapter, the NRC staff evaluates the cumulative impacts of the direct and indirect impacts 

described in Chapter 3 when aggregated with the impacts of other actions that could affect the 

same resources. The NRC staff also evaluates how its findings in Chapter 3 and cumulative 

impact findings in this chapter affect the conclusions provided by U.S. Department of Energy 

(DOE) in its assessment of cumulative impacts on groundwater in Chapter 8 of its 

environmental impact statement (EIS) (DOE, 2002) and Chapter 8 of its supplemental EIS 

(SEIS) (DOE, 2008a). 

A cumulative impact is “the impact on the environment that results from the incremental impact 

of [an] action when added to other past, present, and reasonably foreseeable future actions, 

regardless of what agency (Federal or non-Federal) or person undertakes such other actions” 

(NRC, 2003). Cumulative impacts can result from actions that are individually minor, but 

collectively significant, taking place over a period of time. A proposed project could contribute to 

cumulative impacts when its environmental impacts overlap with those of other past, present, or 

reasonably foreseeable future actions (RFFAs) in a given area. It is possible that a small impact 

from a proposed action could result in a larger cumulative impact when considered in 

combination with the impacts of other actions. The term “reasonably foreseeable” refers to 

future actions for which there is a reasonable expectation that the action could occur, such as a 

proposed action under analysis or a project that has already started. 

This chapter is organized as follows: Section 4.1 describes the NRC staff’s methodology in 

evaluating cumulative impacts; Section 4.2 describes the spatial and temporal boundaries for 

this cumulative impacts assessment; Section 4.3 describes the affected resource areas, 

consistent with the NRC staff’s evaluation of impacts in Chapter 3; Section 4.4 identifies other 

related past, present, and reasonably foreseeable future actions that could contribute to 

cumulative impacts; and Section 4.5 presents the NRC staff’s cumulative impacts analysis for 

the resource areas identified in Section 4.3 and Chapter 3. Sections 4.4 and 4.5 are each 

divided into two sections: the first section presents the information DOE provided in its 2002 

and 2008 EISs; the second section presents the NRC staff’s supplement to the 2002 and 2008 

EISs, based upon the impacts evaluated in Chapter 3. 

Because DOE’s 2008 SEIS summarizes, incorporates by reference, and updates the 

information in the 2002 EIS, this chapter primarily refers to the 2008 SEIS. In addition, the NRC 

staff accepts the information in the 2002 EIS and the 2008 SEIS, unless otherwise noted in this 

chapter. As stated in the Adoption Determination Report (ADR), “[t]he NRC staff concludes that 

the 2002 EIS, the Repository Supplemental EIS, and the Rail Corridor SEIS meet NRC 

completeness and adequacy requirements in title10 of the Code of Federal Regulations (CFR)

51.91 and in 10 CFR Part 51, Subpart A, Appendix A, and that the EISs are generally consistent 

with NRC’s National Environmental Policy Act (NEPA) guidance in NUREG–1748.” 

4.1 Methodology for Supplementing DOE’s Cumulative Groundwater 

Impacts Analysis 

This cumulative impacts assessment examines the incremental groundwater impacts of the 

repository, as evaluated in this supplement, in combination with other past, present, and RFFAs. 

The general approach for assessing cumulative groundwater impacts is based on the principles 

and guidance described in NRC environmental review guidance (NRC, 2003), which 
4-2 

incorporates by reference CEQ’s Considering Cumulative Effects under the National 

Environmental Policy Act (CEQ, 1997) and EPA’s Consideration of Cumulative Impacts in EPA 

Review of NEPA Documents (EPA, 1999c). Based on the review of applicable portions of these 

documents and the NRC’s regulations for implementing NEPA in 10 CFR Part 51, the NRC staff 

used the following methodology for assessing cumulative impacts in this supplement: 

1. The NRC staff reviewed the cumulative impacts analyses in DOE’s EISs to determine 

how these analyses should be supplemented in light of the NRC staff’s findings in 

Chapter 3 of this supplement. As noted in Chapter 1, the NRC staff did not conduct a 

scoping process for this supplement because the scope is already defined in the NRC 

staff’s ADR. 

2. The NRC staff identified several additional RFFAs that were not previously identified in 

DOE’s EISs, but which could impact the relevant resource areas. The NRC staff 

evaluated these actions, along with the actions previously identified by DOE, in the 

cumulative impacts assessment in this supplement. 

3. The affected environment for the cumulative impact analysis is described in Chapter 2. 

The direct and indirect impacts on particular resources, as described in Chapter 3, form 

the basis for the analysis in this chapter. 

4.2 Spatial and Temporal Boundaries for Cumulative Groundwater Impacts 

The spatial boundary for cumulative groundwater impacts consists of the area of the aquifer 

beneath Yucca Mountain and along the aquifer’s flow path that could be affected by 

contaminant releases from the proposed repository (as described in detail in Section 2.2) or by 

other activities having the potential to affect groundwater. The spatial boundary also includes 

the types of areas aboveground where the groundwater from the Yucca Mountain flow path 

could naturally discharge to the surface (described in Section 2.3) or where groundwater is 

pumped, such as at Amargosa Farms (described in Section 2.2.2 and 2.2.3). 

The temporal boundaries for cumulative impacts include impacts from past actions and extend 

to one million years after repository closure. The descriptions of the affected environment 

provided by DOE (2014a; 2008a; 2002), as supplemented by the NRC staff (Chapter 2), already 

encompasses the impacts of past human actions that may have previously affected 

groundwater. The affected area includes vast and remote areas of limited human activity in a 

predominantly naturally occurring state. Thus, the NRC staff concludes that the description of 

the affected environment in Chapter 2 provides a reasonable baseline for the assessment of 

cumulative groundwater impacts. The long duration of the temporal boundary is necessary 

because, as described in Section 3.1.2, DOE and the NRC staff’s analyses indicate that 

contaminants released gradually from the repository would travel through the aquifer and 

potentially reach ground surface locations over a very long timeframe after repository closure. 

The analyses cover a period of one million years following repository closure, the nominal 

“period of geologic stability” used as a basis for defining the postclosure compliance period 

(70 FR 53,313). The NRC staff conducted a review to identify any near-term activities that 

could contribute to long-term cumulative groundwater impacts. However, the NRC staff 

concludes that using unsupportable assumptions about human activities occurring over the next 
4-3 

one million years would result in correspondingly unsupportable conclusions about the 

potential impacts.1

 

4.3 Potentially Affected Resources 

Chapter 2 provides descriptions of the resource areas that could be affected by potential 

groundwater contamination from the repository and surface discharges of contaminated 

groundwater. These areas and their location in Chapter 2 are listed as follows. 

 Groundwater in the volcanic-alluvial aquifer, described in Section 2.2.

 Resources associated with pumping and irrigation at Amargosa Farms, described in 

Sections 2.2 and 2.3. The resources potentially affected at groundwater pumping 

locations include groundwater, soils, ecological resources, and public health 

(including environmental justice concerns). 

 Resources at current natural surface discharge locations (springs and playas) and 

potential future sites of natural surface discharge under a reasonably foreseeable wetter 

climate state, described in Section 2.3. The resources potentially affected at surface 

discharge locations include groundwater, soils, ecological resources, public health 

(including environmental justice concerns), and cultural resources. 

Other past, present, or reasonably foreseeable future actions could contribute to potential 

cumulative impacts on these resources, in addition to the impacts from the proposed repository. 

These other actions are discussed in Section 4.4, and their potential impacts, along with 

impacts from the proposed repository, on these resource areas are discussed in Section 4.5. 

4.4 Other Past, Present, and Reasonably Foreseeable Future Actions 

This section summarizes the other past, present, and future actions identified by DOE in the 

2002 and 2008 EISs (Section 4.4.1) and by the NRC staff for this supplement (Section 4.4.2). 

As described by the CEQ, identifying RFFAs is a critical component of a cumulative impacts 

analysis (CEQ, 1997). However, CEQ also recognizes that agencies should not engage in 

speculation in an effort to identify all actions that could contribute to overall potential cumulative 

effects. Given the long timeframes considered in this supplement, as described in Chapter 2, it 

is not possible to identify or reasonable to speculate about all potential public and private 

projects that could contribute to cumulative groundwater impacts over the course of the next 

one million years. Therefore, the NRC staff reviewed available information for the spatial 

boundary, including information in NEPA analyses and resource management plans, which 

together provide a reasonable picture of potential present or foreseeable future actions. 

4.4.1 Actions Identified in DOE’s EISs 

Section 8.1 of the 2008 SEIS incorporates by reference and updates the information in the 

2002 EIS. This section identifies past, present, and future actions that DOE considered to have 

 

1

This is consistent with NRC regulations in 10 CFR 63.305(b) and EPA regulations in 40 CFR 197.15, which direct 

DOE not to project changes in society, the biosphere (other than climate), human biology, or increases or decreases 

of human knowledge or technology. 
4-4 

the potential to affect the same resources as those that would be affected by the repository. In 

Section 8.1.1, DOE states that the description of the existing environmental conditions in 

Chapter 3 of DOE’s 2008 SEIS accounts for the impacts of past and present actions on the 

environment that the repository would affect. In Chapter 3 of that document, DOE describes the 

results of groundwater sampling to support its description of regional groundwater quality. DOE 

also provides information about contaminants in groundwater from past activities at the Nevada 

National Security Site (NNSS; formerly the Nevada Test Site). DOE used the baseline 

information in Chapter 3 to develop its assessment of the incremental environmental impacts of 

the proposed repository and, thus, its assessment of cumulative impacts. 

The region of influence (or spatial boundary) DOE defined for its groundwater impacts 

assessment and used for its cumulative impacts assessment, as described in Section 4.1.3 of 

the 2002 EIS and referenced in Section 4.1.3 of the 2008 SEIS, includes “aquifers under the 

areas of construction and operations that DOE could use to obtain water, and downstream 

aquifers that repository use or long-term releases from the repository could affect.” In its 

description of the groundwater environment in Chapter 3 of the 2002 EIS, DOE included the 

volcanic-alluvial aquifer and the lower carbonate aquifer as the aquifers that could be affected 

by radionuclide releases from the repository and by other Federal, non-Federal, and private 

activities. The NRC staff concludes that DOE’s spatial boundary is appropriate for the purpose 

of identifying other past, present, and reasonably foreseeable future actions that could 

contribute to cumulative groundwater impacts because this area encompasses the flow path 

from the repository to potential discharge points and is thus consistent with the spatial boundary 

for groundwater impacts defined by the NRC staff in Section 4.2 of this supplement. 

Other Federal, non-Federal, or Private Activities Identified by DOE 

This section describes the actions DOE identified in its EISs as potential contributors to 

cumulative groundwater impacts. 

Section 8.3.2 of the 2008 SEIS examines the cumulative impacts from past, present, and 

reasonably foreseeable future actions that have the potential to affect resources after repository 

closure. The actions DOE identified that could have the potential to contribute to long-term 

cumulative groundwater impacts are (i) past, present, and reasonably future actions at the 

NNSS, including nuclear weapons testing and radioactive waste management; and (ii) past and 

present actions at a low-level radioactive waste disposal facility and hazardous waste disposal 

facility located about 16 km [10 mi] southeast of Beatty, Nevada, or 15 km [9.3 mi] west of the 

proposed repository. 

In its EISs, DOE did not identify mining as a potential contributor to cumulative groundwater 

impacts. Because there is currently mining activity within the spatial boundary for this analysis, 

the NRC staff determines that further assessment of these activities is needed. Section 4.4.2 

provides more information about regional mining activity. 

Additional Inventory Modules 

Under the Nuclear Waste Policy Act (NWPA), the proposed repository would be a permanent 

disposal facility for up to 70,000 metric tons of spent nuclear fuel (SNF) and high-level 

radioactive waste (HLW). The NWPA requires the NRC to include in any construction 

authorization a condition prohibiting the emplacement of more than 70,000 metric tons of heavy 

metal or a quantity of solidified high-level radioactive waste resulting from the reprocessing of 

such a quantity of spent fuel in the first repository until a second repository is in operation 
4-5 

[NWPA, Section 114(d)]. DOE’s proposed action, as described in its 2002 and 2008 EISs and 

in its Safety Analysis Report (SAR) (DOE, 2008b), is the construction of a repository and 

emplacement of up to 70,000 metric tons of spent nuclear fuel and high-level radioactive waste. 

In its 2002 EIS and 2008 SEIS analyses of cumulative impacts, DOE also included two RFFAs 

for the emplacement of waste beyond the 70,000-metric-ton limit, which DOE referred to as 

inventory modules. These modules accounted for the emplacement of additional SNF and other 

HLW, as well as Greater-Than-Class-C waste, at the Yucca Mountain repository. For this 

supplement, the NRC staff does not consider the inventory modules to be RFFAs because 

(i) DOE did not account for the additional waste inventories in its license application; and (ii) the 

NWPA prohibits both modules until such time as a second repository is in operation. Since no 

repository has been licensed, and no second repository is under consideration, the NRC staff 

concludes that a second repository is not reasonably foreseeable. The NRC staff further 

concludes that the modules are likewise speculative, therefore are not RFFAs, and are not 

considered further. If Congress enacts legislation that allows for the disposal of additional 

waste inventories at the Yucca Mountain repository before a second repository is in operation, 

any updated license application and associated environmental review would necessarily 

analyze the change in the proposed action. 

NRC Staff Conclusions Regarding DOE’s Identification of Other Actions 

The NRC staff makes the following conclusions regarding the region of influence and 

identification of other actions in DOE’s EISs: 

 The NRC staff finds that the region of influence (spatial boundary) DOE used for 

identifying other actions that could affect groundwater is acceptable and reasonable 

because it extends throughout the area of the aquifer that could be affected by the 

repository or that would flow downstream to merge with groundwater flowing from the 

repository area, consistent with the description in Chapter 2 of the affected environment. 

 The NRC staff has determined that in its EISs, DOE identified past, present, and 

reasonably foreseeable future actions that could affect groundwater along the flow path 

from the repository to the postclosure compliance location {18 km [11 mi] south of the 

repository site}. Specifically, the NRC staff finds that DOE appropriately identified the 

NNSS and the Beatty low-level radioactive waste disposal site as potential contributors 

to cumulative groundwater impacts after repository closure. The NRC staff concludes 

that the actions identified by DOE are reasonable for the evaluation of cumulative 

impacts at the postclosure compliance location and are acceptable for evaluation of 

cumulative impacts in this supplement because the actions may affect the regional 

groundwater flow system that would be affected by the repository. 

 The NRC staff finds that the DOE EISs did not identify regional mining activity as a past, 

present, and reasonably foreseeable future action that could affect groundwater along 

the flow path from the repository to the postclosure compliance location. Therefore, the

NRC staff has included information about regional mining in Section 4.4.2. 

 For the reasons given in the previous section, the NRC staff concludes that the 

additional inventory modules are not reasonably foreseeable actions and does not 

address them further in this supplement. 

 Because this supplement assesses groundwater impacts along the predominant 

groundwater flow path to the pumping location in Amargosa Farms and to surface 
4-6 

discharge locations in Death Valley, the NRC staff determines that further assessment is 

needed to determine whether there are (i) actions not identified by DOE, in addition to 

mining, that could affect groundwater downgradient from the postclosure compliance 

location and (ii) actions that could affect other resources at Amargosa Farms and at 

downgradient surface discharge locations, including those identified in DOE’s EISs but 

not considered with the impacts identified in Chapter 3 of this supplement. 

 DOE’s analysis, as updated in the 2008 SEIS, is limited to actions already occurring or 

planned as of 2008. Thus, the NRC staff concludes that further supplementation is 

needed to describe actions planned or occurring since 2008 that could contribute to 

cumulative groundwater impacts, and to evaluate their potential cumulative impacts. 

The results of the NRC staff’s review are discussed in the next section. 

4.4.2 NRC Staff Update and Supplementation of DOE EISs Identification of 

Other Actions 

As discussed in the previous section, DOE’s analysis included an assessment of impacts on 

groundwater at the postclosure compliance location. To address impacts on groundwater and 

from surface discharges of groundwater along the flow path beyond Amargosa Valley, the NRC 

staff supplements DOE’s assessment by evaluating groundwater impacts at Amargosa Farms 

and at natural surface discharge locations in Death Valley. For this cumulative impacts 

assessment, the NRC staff has reviewed available information to determine whether other 

actions could affect the groundwater or resources at the surface discharge locations. In 

addition, the NRC staff has reviewed available information to determine whether actions 

planned or occurring after 2008 could have the potential to contribute to cumulative 

groundwater impacts. 

The NRC staff consulted sources of publicly available information on existing and proposed 

activities, such as government websites, EISs, and resource management plans. The NRC 

staff also contacted Department of Interior (DOI), Bureau of Land Management (BLM) staff 

knowledgeable about RFFAs in the region. 

Nevada National Security Site 

DOE’s National Nuclear Security Administration (NNSA) published its Final Site-Wide 

Environmental Impact Statement for the Continued Operation of the Department of 

Energy/National Nuclear Security Administration Nevada National Security Site and Off-Site 

Locations in the State of Nevada (DOE/EIS-0426) (NNSS SWEIS) in February 2013. The 

NNSS SWEIS assesses the potential environmental impacts of three alternatives for continued 

operations at the NNSS and operations at other DOE/NNSA-managed sites in southern 

Nevada. These alternatives are organized under three mission areas: (i) the National 

Security/Defense Mission, which addresses stockpile stewardship and management, nuclear 

emergency response, nonproliferation, counterterrorism, and other work; (ii) the Environmental 

Management Mission, which addresses waste management and environmental restoration; and 

(iii) the Nondefense Mission, which addresses general site support and infrastructure, 

conservation and renewable energy, and other research and development programs. 

The sites in the spatial boundary of the NNSS SWEIS are the NNSS, the Tonopah Test Range 

{about 19 km [12 mi] north of the NNSS northern boundary}, and environmental restoration 

areas on the U.S. Air Force Nevada Test and Training Range (adjacent to the west, north, and 
4-7 

east of the NNSS). The three alternatives include similar types of programs, capabilities, 

projects, and activities, but differ primarily in their levels of operations and facility requirements. 

The NRC staff reviewed the December 30, 2014 Record of Decision (ROD) (79 FR 78421) and 

the NNSS SWEIS to determine whether any proposed or continuing activities could contribute to 

cumulative groundwater impacts within the spatial boundary of this analysis. The ROD and the 

NNSS SWEIS (DOE, 2013a; 2014c) state that DOE/NNSA would add new projects at the 

NNSS, including activities in the areas of nonproliferation and counterterrorism, high-hazard 

experiments involving explosives and nuclear materials, research and development, testing, 

renewable energy, and the disposal of a wide variety of wastes. Activities proposed for the 

Tonopah Test Range include the continuation of current activities (primarily weapons testing, 

experiments, and research and development) as well as improving infrastructure (such as 

communications, electrical transmission, and buildings) (DOE, 2013a; Table 3-3). 

In addition, DOE/NNSA would continue or start new projects on the NNSS to manage or 

dispose of low-level radioactive waste (LLRW), LLRW mixed with hazardous waste (mixed 

LLRW), hazardous waste, solid waste, explosives ordnance, and site remediation wastes. With 

the exception of a proposed solid waste management facility that would be located in Area 25 

(adjacent to the east of the Yucca Mountain site), all of these waste management activities are 

or would be located in the easternmost areas of the NNSS, more than 30 km [19 mi] from the 

proposed repository site. The depth to the water table in these eastern areas of the NNSS 

ranges from over 500 ft [152 m] to nearly 2,000 ft [610 m] (Winograd and Thordarson, 1975; 

DOE, 2013a; Section 4.1.6.2). 

DOE/NNSA concludes that none of the proposed activities described in the NNSS SWEIS for 

the NNSS, the Tonopah Test Range, or the Nevada Test and Training Range would contribute 

to NNSS cumulative groundwater impacts (DOE, 2013a; Tables 3-4, 3-7). The NRC staff finds 

the conclusions of the NNSS SWEIS for these proposed new and continuing activities to be 

reasonable and acceptable, based on the NRC staff’s understanding of the activities and that 

DOE/NNSS would continue managing the various types of wastes in compliance with applicable 

requirements, as described in Section 4.1.11 of the NNSS SWEIS. 

Solar Energy Projects 

DOI BLM has approved several renewable energy projects in Nevada and California in recent 

years as part of a larger, national effort to promote the growth of solar, wind, and geothermal 

energy generation. None of the approved solar, geothermal, or wind energy projects are 

located within the region of influence identified for this supplement (i.e., the geographic area 

overlying the area of the aquifer that could be affected by the repository or that would flow 

downstream to merge with groundwater flowing from the repository). However, three areas 

within the region of influence may be developed as solar energy facilities. Two of the areas 

could be developed as small (50-megawatt) photovoltaic energy facilities (Helseth, 2015). The 

third area is a larger zone designated recently by the BLM and DOE as a “solar energy zone” 

(SEZ), established as part of a BLM program to encourage solar energy development. This 

zone, named the Amargosa Valley SEZ, is located in the Amargosa Desert between the Funeral 

Mountains to the southwest and Yucca Mountain to the northeast. The SEZ is on BLMadministered land and the developable area within it is 8,479 acres [34.3 km2

]. There are no 

pending solar applications within the SEZ, but the BLM will encourage future interested parties 

to site projects within this zone (BLM, 2012a,b). Withdrawal of small amounts of water for 

construction {approximately 200 acre-ft [246,700 m3

] per photovoltaic facility} or operations 

{approximately 5 acre-ft [6,170 m3

] per photovoltaic facility per year} would be the principal 

impact on groundwater from the development of solar energy in this area (Helseth, 2015). The 
4-8 

NRC staff concludes that these solar projects would not regularly produce liquid wastes, with 

the exception of sanitary wastewater and, depending on the type and size of the facility, 

blowdown water from a steam boiler. Such wastewaters would be retained (e.g., in septic 

systems or evaporative ponds) and would not be discharged to groundwater (BLM, 2010; 

Section 5.9). Therefore, the NRC staff concludes that these activities would not result in 

groundwater contamination and would not contribute to cumulative groundwater impacts.

Mining Activities 

The BLM administers the mineral estate on public lands in Southern Nevada. The BLM 

Las Vegas and Pahrump Field Offices Draft Resource Management Plan/Environmental Impact 

Statement (BLM, 2014) describes historic, current, and future trends in mining activities in 

various regions of southern Nevada and evaluates the potential environmental impacts. The 

BLM EIS describes mining activities that have occurred in the vicinity of the town of Beatty and 

in Amargosa Valley, which are limited in the number of operations. These areas are within the 

region encompassed by the groundwater flow paths considered in this supplement, as 

described in Section 2.2.2. The mining activities include current gold and silver mining in the 

Bare Mountain district in the vicinity of Beatty, Nevada. Current conditions include one open pit 

and two underground mines. BLM indicates the level of precious metal mining activity is linked 

to market conditions, and future mining trends are, therefore, difficult to forecast. 

Amargosa Valley (in both Nevada and California) produces nonmetallic resources, including 

magnesium clays (used as binding agents, thickeners, gels, and in filtering) and zeolites 

(used in filtration systems, cat litter, and animal feed). Current conditions include ongoing 

production that has been limited by the recent economic recession. BLM projects that 

production would improve as the local, regional, or global economy improves. The BLM EIS 

impact analysis states that mineral extraction has the potential to impact surface water and 

groundwater quality due to increased sedimentation from surface disturbances and the potential 

for releases of wastewater. BLM concludes that the degree of impacts would depend on the 

level of preplanning and analysis, the provision of bonding to ensure sufficient funds would be 

available to mitigate potential impacts, and the regulatory stipulations aimed at protecting 

wildlife and other resource values, which would also protect water resources. BLM concludes 

impacts could be negligible to moderate but would be addressed through best management 

practices and other mitigation. Based on the information provided in the BLM EIS, the NRC 

staff concludes that the extent of mining activity in the region of the groundwater flow path is 

limited, and the existing permitting and associated regulatory protections would limit potential 

groundwater impacts to minimal levels. Based on this review, the NRC staff concludes that the 

omission of mining activities from the DOE cumulative impact analysis is not likely to have 

affected impact conclusions; however, these activities are included in the NRC supplement. 

The NRC staff evaluated the description of other land uses for the repository site provided in 

DOE’s SAR (DOE, 2008b), and conducted an independent evaluation of the Yucca Mountain 

site description as part of its review (NRC, 2015a, Section 2.1.1.1.3.9; NRC 2014b, 

Sections 2.5.8 and 2.5.9). Based on the results of this review, the NRC staff has not identified 

other activities that would contribute to cumulative groundwater impacts. 

4.5 Cumulative Impacts on Groundwater and from Surface Discharges 

This section evaluates repository impacts on groundwater and from surface discharges when 

added to the aggregate effects of other past, present, and reasonably foreseeable future 

actions. As described in Chapter 3, the incremental impacts for all resource areas and locations 

would be SMALL. This section provides the NRC staff’s review of the cumulative impact 
4-9 

assessment in DOE’s EISs (Section 4.5.1) and the NRC staff’s supplement to the cumulative 

impacts analyses in DOE’s EISs for the impacts identified in Chapter 3 (Section 4.5.2). 

4.5.1 Impact Assessment in DOE’s EISs 

In Section 8.3.2 of the 2002 EIS (as updated in Section 8.3.2 of DOE’s 2008 SEIS), DOE 

assessed the potential cumulative impacts from other Federal, non-Federal, and private actions 

that could contribute to doses from modeled groundwater contamination at the postclosure

compliance location, which is the location of the reasonably maximally exposed individual 

(RMEI), as defined in 40 CFR 197.21. DOE assessed the cumulative impacts associated with 

the NNSS and the Beatty waste management and disposal sites. A summary of DOE’s 

assessments and the NRC staff’s conclusions regarding DOE’s assessments are provided in 

the sections that follow. 

Nevada National Security Site 

In the 2002 EIS, DOE made assumptions about the magnitude and timing of radiological 

releases from the NNSS (assuming, for example, that the peak groundwater concentrations of 

contaminants from the NNSS would coincide in time and space with the peak groundwater 

concentrations from repository contaminants). The NRC staff considers these assumptions to 

be conservative because the maximum concentrations of groundwater contaminants flowing 

from the repository and from multiple locations in the NNSS through a vast space for hundreds 

of thousands of years are unlikely to reach the same location at the same time. DOE also 

assumed that any contaminated groundwater from the NNSS would flow along the same paths 

as those for repository contaminants (DOE, 2002). The NRC staff also considers this to be a 

conservative assumption because the different groundwater flow paths for the NNSS 

contaminants are likely to cause dispersion of contaminants, depending on factors such as 

solubility, sorption rates, and the volume of groundwater flow. Based on available information 

about contamination migrating from the NNSS (DOE, 2013a), the NRC staff concludes that 

DOE’s assumptions as described previously are reasonable and conservative in considering the 

potential cumulative groundwater impacts from the NNSS. 

In assessing potential impacts from future LLRW disposal activities in Areas 3 and 5 of the 

NNSS, DOE summarized various ongoing and proposed LLRW and mixed LLRW activities in its 

2002 EIS (Section 8.3.2.1.3). DOE concluded that the only possible groundwater impacts from 

these activities would be from a few hazardous chemicals (1,2-dichloroethane, methylene 

chloride, and benzene), but that these chemicals are not within the inventory of chemicals from 

the repository. The NRC staff agrees that these chemicals are not among those that would be 

released from the repository. Further, the depth to the water table in Areas 3 and 5 ranges from 

over 500 ft [152 m] to nearly 2,000 ft [610 m] (DOE, 2013a; Section 4.1.6.2; Winograd and 

Thordarson, 1975), and the NRC staff concludes that any small amount of contaminants leaking 

from these LLRW activities would be detected and remediated before they could affect 

groundwater. This conclusion is based on the NRC staff’s assumption that DOE/NNSA would 

continue managing the LLRW and mixed LLRW wastes, in compliance with applicable 

requirements, as described in Section 4.1.11 of the NNSS SWEIS. 

Beatty Low-Level Waste and Hazardous Waste Disposal Facilities 

The Beatty LLRW facility, located on U.S. Highway 95 approximately 12 mi [19 km] south of the 

town of Beatty, stopped accepting radioactive waste in 1992 and is under the permanent 

custody of the Nevada Department of Health and Human Services Division of Public and 
4-10 

Behavioral Health. In Section 8.3.2 of the 2002 EIS, DOE provided an assessment of the 

quantity of radionuclides that could be available for groundwater transport and possibly 

contribute to cumulative groundwater impacts. DOE found the quantity of radionuclides at the 

Beatty site to be a small fraction of the quantity of radionuclides available for release and 

transport from initial failures of waste packages at the proposed Yucca Mountain repository. 

Therefore, DOE concluded that the Beatty LLRW site would be a small contributor to long-term 

cumulative impacts (DOE, 2002). The NRC staff finds DOE’s conclusions about this site are 

supported by the available information and are therefore reasonable and acceptable. 

Additionally, DOE noted that the co-located Beatty hazardous waste treatment, storage, and 

disposal facility is permitted under the Resource Conservation and Recovery Act and has 

engineered barriers and administrative controls that minimize the potential for offsite migration 

of hazardous constituents (DOE, 2002). This is consistent with the NRC staff’s understanding 

of the management of these facilities. In particular, the Beatty facility is equipped with two 

liners, with leachate collection and removal systems placed between and above the liners; thus, 

any leakage from the facility would be collected and removed (NDEP, 2011; Section 7). 

NRC Staff Conclusions Regarding DOE’s Assessment 

DOE’s assumptions and analysis regarding the contribution to radiological and nonradiological 

groundwater contamination by the NNSS and the Beatty site are conservative for assessing the 

cumulative groundwater impacts at the postclosure compliance location. The NRC staff notes 

that a fire occurred at the Beatty low-level radioactive waste disposal site on October 18, 2015. 

An incident report (NDPS, 2015) determined that the fire was caused by openings in the cover 

that allowed water to infiltrate drums of metallic sodium. The report concluded that no injuries to 

personnel occurred, that the effects of the fire were contained to the immediate site, and that no 

radioactive materials were released due to the fire. 

The NRC staff has determined that the groundwater flowing below Yucca Mountain is most 

likely to be impacted by those NNSS activities located in areas of the NNSS in the Alkali FlatFurnace Creek Basin (Figure 2-3). Potential contaminants from NNSS activities in areas of the 

NNSS in the Pahute Mesa-Oasis Valley Basin (Figure 2-3) could also mix with groundwater 

from below Yucca Mountain in the Amargosa Desert area (see discussion in Section 2.2.1). 

Interactions of the Yucca Mountain flow path with water from the Ash Meadows Basin is much 

less likely (Section 2.2.2). Based on the potential contaminants that could be released from the 

NNSS and the Beatty waste disposal facilities and DOE’s analysis, the NRC staff finds DOE’s 

conclusions about the potential cumulative impact contribution of these sites to impacts at the 

postclosure compliance location to be reasonable. The NRC staff, therefore, concludes that 

DOE adequately addressed the possible contributions of radiological contaminants from the 

NNSS and the Beatty LLRW site to cumulative groundwater quality impacts. The NRC staff 

concludes that the NNSS and the Beatty LLRW and hazardous waste facilities are unlikely to 

contribute nonradiological contamination to groundwater. Further, the NRC staff concludes that 

while these sites could contribute to cumulative radiological impacts on groundwater along the 

flow path from the repository, the impacts would be reduced because of the attenuating effects 

of dispersion and radioactive decay as contaminants move through the groundwater flow path 

from the repository. 

4.5.2 NRC Staff Supplementation of DOE EISs Cumulative Impacts Assessment 

The following sections provide the NRC staff’s supplementation to DOE’s cumulative 

groundwater impacts analysis based on (i) the NRC staff’s review of DOE’s identification of 
4-11 

past, present, and future actions in Section 4.4.1; (ii) the NRC staff’s review of DOE’s 

assessment of cumulative impacts in Section 4.5.1; and (iii) the NRC staff’s updated 

identification of past, present, and reasonably foreseeable future actions in Section 4.4.2. 

Updates are included, as necessary, for cumulative groundwater impacts discussed in the 

groundwater subsections of Sections 4.5.2.1 (for the Amargosa Farms area) and 4.5.2.2 

(for natural surface discharge locations). Supplementation is provided for cumulative impacts 

on other affected resources at Amargosa Farms area in Sections 4.5.2.1 (soils, ecological 

resources, public health, and environmental justice) and surface discharge locations in 4.5.2.2 

(soils, ecological resources, public health, environmental justice, and cultural resources). 

4.5.2.1 Cumulative Impacts on Affected Resources at Amargosa Farms 

This section discusses cumulative impacts on groundwater and from pumping and irrigation in 

the affected environment described in Chapter 2. The impacts at Amargosa Farms are reported 

separately from the natural discharge locations because Amargosa Farms is not a natural 

discharge location and the evaluation of impacts involves a consideration of different 

environmental processes and pathways. As in Chapter 3, the analysis of impacts considers 

both the present-day and future cooler/wetter climates. 

4.5.2.2 Groundwater at Amargosa Farms 

Section 3.1.1 describes the incremental impacts on groundwater (the estimated concentrations 

of contaminants in the groundwater) at the Amargosa Farms area, which is approximately 

17 km [11 mi] beyond the postclosure compliance location, or approximately 35 km [22 mi] 

along the flow path from Yucca Mountain. Tables 3-1a and 3-1b show the estimated levels of 

contaminants in the aquifer environment beyond the postclosure compliance location up to 

Amargosa Farms and at Amargosa Farms, respectively. Using the estimated concentrations in 

the Amargosa Farms area as representative of the aquifer that is subject to groundwater 

withdrawal in that area, Table 3-2 lists the average estimated groundwater concentrations of 

radiological and nonradiological material from the repository in the aquifer at Amargosa Farms 

for both the present-day and future wetter climates. As shown in Table 3-2, the estimated total 

concentration of all of the radionuclides in groundwater at Amargosa Farms from releases at the 

repository are lower than the applicable EPA standards for drinking water. No standards have 

been established for the nonradiological contaminants listed in the table, but the concentrations 

of each are much lower than one part per million, and are comparable to natural levels in the 

water (Table 2-2). As stated in the Aquifer Environment section of Section 3.1.1, based on the 

NRC staff’s analysis of the potential future accumulation of radiological and nonradiological 

material released from the repository to the aquifer environment between the postclosure 

compliance location and Amargosa Farms, the NRC staff finds that the incremental impact on 

the aquifer environment beyond the postclosure compliance location would be SMALL.

Based on the information provided in Sections 4.4.1 and 4.4.2 concerning other actions and the 

NRC staff’s conclusions about DOE’s assessment in its EISs of cumulative groundwater 

impacts in Section 4.5.1, the NRC staff has identified only regional mining activity as an 

additional action that was not already identified by DOE as a potential contributor to cumulative 

groundwater impacts. As described in Section 4.4.1, the NRC staff concluded the extent of 

mining activity in the region of the groundwater flow path is limited and considering existing 

regulatory protections, the potential groundwater impacts would be minimal. The NRC staff has 

also identified new information concerning groundwater contamination resulting from past NNSS 

activities, discussed as follows. 
4-12 

As discussed in Section 4.5.1, in its EISs, DOE identified groundwater contamination from the 

NNSS as a possible contributor to cumulative groundwater impacts. Since the 2008 SEIS was 

published, DOE has detected and described contamination migrating off the NNSS. DOE 

provided information on this contamination in the NNSS SWEIS (discussed in Section 4.4.2) 

and it is summarized here. In its NNSS SWEIS description of affected groundwater at the 

NNSS, DOE/NNSA reports that tritium was detected in two offsite wells. In 2009, DOE/NNSA 

detected tritium in Well ER-EC-11, which is less than one half-mile off the northwestern 

boundary of the NNSS on the Nevada Test and Training Range and about 23 km [14 mi] from 

the nearest public water source, a private well. The tritium concentration was 13,180 pCi/L, 

which is below the EPA’s MCL of 20,000 pCi/L. In 2010, DOE/NNSA found low levels of tritium 

(48.3 pCi/L) in Well PM-3, located about 11,000 ft [3,353 m] west of the NNSS boundary on the 

Nevada Test and Training Range (DOE, 2013a). 

DOE/NNSA concluded that tritium releases in this area could eventually flow to the southwest, 

possibly discharging in the Amargosa River area or in Death Valley (DOE, 2013a; 

Section 6.3.6.2). Based on the NRC staff’s knowledge of groundwater flow, as described in 

Chapter 2, and the manner in which tritium moves through groundwater, the NRC staff finds the 

DOE/NNSA conclusion to be reasonable, but that the tritium releases are unlikely to lead to 

appreciable impacts. This is because the NNSS tritium releases would need to travel a long 

distance to the Amargosa Farms area, and because tritium migration identified to date is of 

limited extent. Additionally, as shown in Tables 3-1a, 3-1b, and 3-2, tritium is not a repository 

contaminant likely to reach the aquifer at this location due to the long delay for repository 

releases and the relatively short half-life of tritium (12.3 years). Therefore, the NRC staff 

concludes that tritium from the NNSS would likely decay to negligible levels before arriving at 

Amargosa Farms in conjunction with contaminants from the repository. Therefore, the NRC 

staff concludes that tritium contamination would not contribute cumulatively with the 

radionuclides from the repository. 

Considering the information provided previously regarding regional mining activities, tritium 

releases from the NNSS, and the NRC staff’s conclusions in Section 4.5.1 about DOE’s analysis 

of cumulative groundwater impacts from the NNSS and the Beatty disposal sites, the NRC staff 

concludes that the cumulative impacts on groundwater at the Amargosa Farms area would be 

SMALL because any additional contaminants from these sites would likely not be detectable or 

would be so minor that they would not noticeably alter groundwater characteristics beyond the 

effects that could be attributed to the repository alone.

Soils at Amargosa Farms 

Section 3.1.1 describes the potential accumulation from irrigation of radiological and 

nonradiological contaminants in irrigated soils at Amargosa Farms. Table 3-3 provides 

estimated concentrations in soils at 10,000 and one million years for the present-day and future 

wetter climates, as well as natural background concentrations and U.S. Environmental 

Protection Agency (EPA) screening levels for comparison purposes. As stated in Section 3.1.1, 

the calculated maximum soil concentrations for all of the contaminants are well below the EPA 

generic soil screening levels. Based on the NRC staff’s analysis of the accumulation in soils at 

Amargosa Farms of radiological and nonradiological material released from the repository, the 

NRC staff finds that the incremental impact on soils at Amargosa Farms would be SMALL. 

Based on the information provided in Sections 4.4.1 and 4.4.2 concerning other actions, the 

NRC staff has identified only regional mining activity impacts on groundwater and NNSS tritium 

releases as additional actions or impacts that could contribute to cumulative soils impacts at the 
4-13 

irrigated Amargosa Farms area. Given the NRC staff’s assessment of cumulative groundwater 

impacts provided in the previous section, which indicates that potential mining impacts would be 

mitigated by regulatory controls and would have minimal impacts on groundwater, and the NRC 

staff’s conclusions in Section 4.5.1 about DOE’s analysis of cumulative groundwater impacts 

from the NNSS and the Beatty disposal sites, the NRC staff concludes that the cumulative 

impacts on soils at the Amargosa Farms area from irrigation would be minimal and would not 

noticeably alter the soils beyond the potential impacts that could be attributed to the 

repository alone.

Public Health at Amargosa Farms 

Section 3.1.1 provides the potential impacts at the Amargosa Farms area of groundwater 

contaminants on public health associated with external exposure, inhalation of soil particles and 

from evaporative coolers, and ingestion of water, crops, animal products, fish, and soil. As 

stated in that section, the largest contributors to dose for both the present-day and future wetter 

climates at Amargosa Farms are I-129, Tc-99, Np-237, and Th-230. At 10,000 years, I-129 and 

Tc-99 are the primary contributors to dose. Table 3-4 lists the peak annual dose estimates. 

The peak dose of 1.3 mrem/yr [0.013 mSv/yr] (occurring at one million years for the wetter 

climate) is a small fraction of the dose from natural background levels of approximately 300 

mrem/yr [3.0 mSv/yr] (including radon) for Amargosa Valley, and is much lower than the NRC 

annual dose standards for a Yucca Mountain repository in 10 CFR Part 63 {15 mrem [0.15 mSv] 

for the first 10,000 years, and 100 mrem [1 mSv] for one million years, after permanent closure}. 

The NRC staff assessed human health impacts from nonradiological contaminants by 

comparing daily intakes with EPA’s Oral Reference Dose standard. Table 3-5 provides the 

estimated values of peak daily intakes for each of the nonradiological contaminants for the 

one-million-year period and shows that these values are lower than the EPA Oral Reference 

Doses. The Oral Reference Doses are the levels below which no detectable health effects 

would occur. As stated in Section 3.1.1, based on the NRC staff’s analyses of radiological and 

nonradiological material released from the repository to the Amargosa Farms area, the NRC 

staff finds that the incremental impact of contaminants released from the repository on public 

health at the Amargosa Farms area would be SMALL. 

Based on the information provided in Sections 4.4.1 and 4.4.2 concerning other actions, the 

NRC staff has identified only regional mining activity impacts on groundwater and NNSS tritium 

releases as additional actions or impacts that could contribute to cumulative public health 

impacts at the Amargosa Farms area. The NRC staff’s assessment above of cumulative 

groundwater impacts at Amargosa Farms notes that, because tritium released from the NNSS 

would need to travel a long distance to the Amargosa Farms area, tritium from the NNSS would 

likely decay to negligible levels before arriving at Amargosa Farms in conjunction with 

contaminants from the repository. Given the NRC staff’s assessment of cumulative 

groundwater and cumulative soils impacts at Amargosa Farms provided in the previous 

sections, and the NRC staff’s conclusions in Section 4.5.1 about DOE’s analysis of cumulative 

groundwater impacts from the NNSS and the Beatty disposal sites, the NRC staff concludes 

that the cumulative impacts on public health at the Amargosa Farms area would be minimal and 

would not noticeably affect public health beyond the potential public health impacts from the 

repository alone. 
4-14 

Ecological Resources at Amargosa Farms 

Section 3.2 discusses the incremental impacts on ecological resources in the Amargosa Farms 

area. The NRC staff evaluated the potential for nonhuman biota to be exposed to radionuclides 

at the Amargosa Farms area, based on the estimated magnitude of radioactivity in the 

environment as quantified by the human dose estimates provided in Sections 3.1.1 and 3.1.2. 

Because the human dose estimates are a small fraction of background radiation exposure, the 

NRC staff concludes in Section 3.2 that the estimated levels of radioactivity in the environment 

would be well below levels of concern for potential impacts to nonhuman biota. 

The NRC staff also evaluated the potential for nonhuman biota to be exposed to potentially 

harmful levels of nonradiological chemicals at Amargosa Farms, based on the aquifer and soil 

concentrations in Sections 3.1.1 and 3.1.2 for present-day and future wetter climates and for 

both 10,000-year and one-million-year timeframes. The NRC staff compared the estimated 

aquifer and soil concentrations with ecological impact concentrations from available scientific 

data on the toxicity of the relevant chemicals. Table 3-15 compares estimated aquifer and soil 

concentrations at Amargosa Farms with ecological impact concentrations. The estimated water 

and soil concentrations of radiological and nonradiological contaminants at Amargosa Farms 

are below the ecological impact threshold concentrations; therefore, the NRC staff concludes 

that incremental environmental impacts to nonhuman biota from these constituents would 

be SMALL. 

Based on the information provided in Sections 4.4.1 and 4.4.2 concerning other actions, the 

NRC staff has identified only regional mining activity and NNSS tritium releases as additional 

actions or impacts that could contribute to cumulative ecological resources impacts at the 

Amargosa Farms area. Given the NRC staff’s assessment of cumulative groundwater, soil, and 

public health impacts at Amargosa Farms provided previously, and the NRC staff’s conclusions 

in Section 4.5.1 about DOE’s analysis of cumulative groundwater impacts from the NNSS and 

the Beatty disposal sites, the NRC staff concludes that the cumulative impacts on ecological 

resources at the Amargosa Farms area would be nonexistent or so small as to not be 

detectable or not noticeably affect nonhuman biota beyond the potential impacts from the 

repository alone. 

Environmental Justice at Amargosa Farms

Section 3.4.2 provides the NRC staff’s assessment of the potential for disproportionately high 

and adverse human health or environmental effects on minority and low-income populations in 

the Amargosa Valley area. Based on the information presented in Table 3-18, the NRC staff 

concludes that the low-income population in the Amargosa Valley Census County Division is a 

significant environmental justice population. Section 3.4.2 further states that based on the 

conclusions in Section 3.1.1 concerning impacts on groundwater, soils, and human health, that 

the NRC staff finds no environmental pathway that would physiologically affect minority or 

low-income populations differently from other segments of the general population. Therefore, 

the NRC staff concludes that no disproportionately high and adverse health or environmental 

impacts would occur to minority or low-income populations in the Amargosa Valley area. 

Because the NRC staff has not identified any impacts related to environmental justice in the 

Amargosa Valley area, the NRC staff concludes that, likewise, no cumulative impacts related to 

environmental justice would occur in this area. 
4-15 

4.5.2.3 Cumulative Impacts on Affected Resources at Natural Surface 

Discharge Locations 

This section evaluates cumulative impacts at current and potential future natural surface 

discharge locations (identified in Chapter 2). As in Chapter 3, the discussion of natural 

discharge locations considers both the present-day and future cooler/wetter climates. The 

potential future discharge locations are conservatively based on a future cooler/wetter climate. 

Groundwater at Natural Surface Discharge Locations 

In Chapter 3, the NRC staff assessed potential incremental groundwater impacts at the 

State Line Deposits/Franklin Well area (Section 3.1.2.1), the Furnace Creek springs area 

(Section 3.1.2.2), the Middle Basin area (Section 3.1.2.2), and at Alkali Flat (Section 3.1.2.3). 

Summaries of these impact assessments and the NRC staff’s conclusions for these areas are 

provided as follows. 

The State Line Deposits (paleospring deposits) are in the area where the Amargosa River and 

Fortymile Wash join and the Franklin Well area refers to the stretch of the Amargosa River 

channel at the southern extent of the State Line Deposits area. There is no current surface 

discharge at this location, except for limited evapotranspiration in a narrow band of vegetation at 

Franklin Well (Section 2.3.3). Paleospring deposits at this location indicate that surface springs 

and playas are likely in a future cooler/wetter climate (Section 2.3.4). Section 3.1.2.1 describes 

several features of the aquifer environment in this area (e.g., its location downstream of 

Amargosa Farms and dilution from mixing with uncontaminated groundwater) that lead the NRC 

staff to conclude that groundwater concentrations and accumulations of material sorbed onto 

sediments would be less than in the aquifer environment at Amargosa Farms. The NRC staff 

concludes that the incremental impact on groundwater at the State Line Deposits/Franklin Well 

area would be SMALL. 

To estimate groundwater impacts at Furnace Creek, the NRC staff conservatively assumed that 

the entire groundwater contaminant plume would discharge to Furnace Creek (instead of 

discharging partially at this location and partially at Middle Basin). Table 3-9 presents the 

estimated average concentrations of important radionuclides and nonradiological elements in 

groundwater discharging at Furnace Creek. The NRC staff finds that the only radiological and 

nonradiological material reaching Furnace Creek would be small amounts of Tc-99, I-129, and 

Mo, and thus the NRC staff finds that the incremental groundwater impacts at Furnace Creek 

would be SMALL. 

To estimate groundwater impacts at Middle Basin, the NRC staff conservatively assumed that 

the entire groundwater contaminant plume would discharge to Middle Basin (instead of 

discharging partially at the Basin and partially at Furnace Creek). The NRC staff concludes that 

groundwater concentrations of the elements listed in Table 3-9 (for Furnace Creek) would be 

similar for discharges at the Middle Basin, but it is unlikely that free-flowing water would appear 

in the wet playa environment. As discussed in Section 3.1.2.2, the only radiological and 

nonradiological material reaching Middle Basin would be small amounts of Tc-99, I-129, and 

Mo, and thus the NRC staff finds that the incremental groundwater impact at Middle Basin 

would be SMALL. 

Conservatively assuming that there is limited or no pumping at the Amargosa Farms area, 

groundwater modeling indicates that the majority of contaminants transported from 

Yucca Mountain will be discharged at Furnace Creek (or the State Line Deposits area in a future 
4-16 

wetter climate) prior to reaching Middle Basin in Death Valley. The NRC staff concludes that 

only a small fraction of contaminants may be directed southward toward the Alkali Flat area. 

For this reason, as stated in Section 3.1.2.3, the NRC staff did not calculate estimates of 

contaminants in the groundwater at Alkali Flat. Rather, the NRC staff observes that the portion 

of the contaminant plume reaching Alkali Flat is less than 1 percent, and concludes that the 

incremental groundwater impacts at Alkali Flat would be a small fraction of those calculated for 

the other surface discharge areas. Therefore, incremental groundwater impacts for Alkali Flat 

would be SMALL. 

Based on the information provided in Sections 4.4.1 and 4.4.2 concerning other actions, the 

NRC staff has identified only regional mining activity and NNSS tritium releases as additional 

actions or impacts that could contribute to groundwater impacts at surface discharge locations. 

Because tritium released from the NNSS would need to travel a long distance to these locations 

(further than for Amargosa Farms), tritium from the NNSS would likely decay to negligible levels 

before arriving at any surface discharge locations in conjunction with contaminants from the 

repository. Based on the NRC staff’s conclusions in Section 4.5.1 about DOE’s analysis of 

cumulative groundwater impacts from the NNSS and the Beatty disposal sites, and the 

NRC staff’s assessment in Section 4.5.2.1 of cumulative groundwater impacts at the 

Amargosa Farms area, the NRC staff concludes that the cumulative impacts on groundwater at 

these surface discharge areas would be minimal and would not noticeably alter groundwater 

characteristics beyond the effects that could be attributed to the repository alone. 

Soils at Natural Surface Discharge Locations 

In Chapter 3, the NRC staff assesses potential incremental soil impacts at the State Line 

Deposits/Franklin Well area (Section 3.1.2.1), the Furnace Creek and Middle Basin areas 

(Section 3.1.2.2), and Alkali Flat (3.1.2.3). Summaries of the assessments and the NRC staff’s 

conclusions for these areas are provided as follows. 

Section 3.1.2.1 provides estimates of soil contaminant concentrations for the wet climate at the 

State Line Deposits/Franklin Well area because the NRC staff finds that contaminants would 

accumulate in soils only for the cooler/wetter climate state, when the water table could rise 

approximately 20 to 30 m [66 to 98 ft] above its present level. Table 3-6 provides estimates of 

the concentrations of radiological and nonradiological constituents in soil for this area under the 

cooler/wetter climate. At one million years, all contaminants remain below screening and impact 

levels, as shown in Table 3-6 and as described further in Section 3.1.2.1. Based on the NRC 

staff’s analysis of the accumulation in soils of radiological and nonradiological material released 

from the repository, the NRC staff finds that the incremental impact on soils in the State Line 

Deposits/Franklin Well area would be SMALL. 

Section 3.1.2.2 describes the accumulation of repository materials in soils at Furnace Creek and 

Middle Basin in Death Valley. Radionuclide contaminants would not reach either location in 

Death Valley within 10,000 years under the present-day climate, even with limited or no 

pumping. Over the longer time period, and in the cooler/wetter climate, only nonsorbing 

contaminants would reach Death Valley. Table 3-10 provides estimates of maximum 

soil/evaporite contaminant concentrations for radiological (I-129 and Tc-99) and nonradiological 

(Mo) constituents for these areas. Because the soil accumulations of radiological and 

nonradiological contaminants are very low, the NRC staff finds that incremental soil impacts 

associated with natural groundwater discharges at Furnace Creek springs and Middle Basin 

would be SMALL. 
4-17 

As stated in Section 3.1.2.3, the NRC staff did not specifically calculate estimates of 

contaminants in the groundwater at Alkali Flat and thus did not calculate concentrations in soils. 

Rather, the NRC staff observes that the portion of the contaminant plume reaching Alkali Flat is 

expected to be very small (less than 1 percent of the potential release reaching the postclosure 

compliance location) and concludes that the incremental groundwater impacts at Alkali Flat 

would be a small fraction of those calculated for the other surface discharge areas. Thus, the 

resulting impacts on soils at Alkali Flat would also be a small fraction of the impacts on soils 

at the other discharge locations. Therefore, incremental soil impacts for Alkali Flat would 

be SMALL. 

Based on the information provided in Sections 4.4.1 and 4.4.2 concerning other actions, the 

NRC staff has identified only regional mining activity and NNSS tritium releases as additional 

actions or impacts that could contribute to cumulative soils impacts at the State Line 

Deposits/Franklin Well area, the Furnace Creek and Middle Basin areas of Death Valley, and at 

Alkali Flat. Given the NRC staff’s assessment of cumulative groundwater impacts provided in 

the previous section and for the Amargosa Farms area (Section 4.5.2.1), and the NRC staff’s 

conclusions in Section 4.5.1 about DOE’s analysis of cumulative groundwater impacts from the 

NNSS and the Beatty disposal sites, the NRC staff concludes that the cumulative impacts on 

soils at these areas would be minimal and would not noticeably alter the soil composition 

beyond the potential impacts from the repository alone. 

Public Health at Natural Surface Discharge Locations 

In Chapter 3, the NRC staff assessed potential incremental public health impacts at the State 

Line Deposits/Franklin Well area (Section 3.1.2.1), the Furnace Creek springs and Middle Basin 

areas (Section 3.1.2.2), and at Alkali Flat (Section 3.1.2.3). Summaries of these assessments 

and the NRC staff’s conclusions for these areas are provided as follows. 

The largest contributors to dose for both the present-day and future cooler/wetter climates at 

the State Line Deposits area are I-129, Tc-99, Np-237, and Pu-242 (Figure 3-3). 

Combined-radionuclide peak dose (including all radionuclides) and body intake for 

nonradiological chemicals are provided in Table 3-7 for 10,000 and one million years for the 

future wetter climates. Section 3.1.2.1 states that estimates of dose and nonradiological body 

intake for the present-day climate are extremely small because of the small area affected 

(Franklin Well area) and the limited amount of evapotranspiration. For the future cooler/wetter 

climates, the peak dose of 0.34 mrem/yr [0.0034 mSv/yr] in Table 3-7 is a small fraction of 

the dose from natural background levels of approximately 300 mrem/yr [3.0 mSv/yr] 

(including radon) for Amargosa Valley and much lower than the NRC annual dose standards for 

a Yucca Mountain repository in 10 CFR Part 63 {15 mrem [0.15 mSv] for the first 10,000 years, 

and 100 mrem [1 mSv] for one million years, after permanent closure}. For all of the 

nonradiological contaminants at this location in the cooler/wetter climate, the estimates of body 

intake are significantly lower than the EPA Oral Reference Dose. Based on the NRC staff’s 

analyses of radiological and nonradiological material released from the repository to the State 

Line Deposits/Franklin Well area, the NRC staff finds that the impact to public health would 

be SMALL. 

Section 3.1.2.2 evaluates the public health impacts of estimated discharges at Furnace Creek 

and Middle Basin. Because of the longer flow path and sorption in the aquifer, only nonsorbing 

radionuclides reach the natural discharge locations in Death Valley. The primary contributors to 

dose at this location are the nonsorbing radionuclides Tc-99 and I-129. Table 3-11 in 

Section 3.1.2.2 provides the peak annual dose estimates for the Furnace Creek area. All 
4-18 

estimated doses for either climate state are below 1 mrem [0.01 mSv], which is a small fraction 

of the dose from natural background levels of approximately 300 mrem/yr [3.0 mSv/yr] 

(including radon) for Amargosa Valley and much lower than the NRC annual dose standards for 

a Yucca Mountain repository in 10 CFR Part 63 {15 mrem [0.15 mSv] for the first 10,000 years, 

and 100 mrem [1 mSv] for one million years, after permanent closure}. The only nonradiological 

contaminant from the repository determined to be present in groundwater discharging at 

Furnace Creek is Mo, because of the longer flow path and sorption in the aquifer (Mo is 

conservatively assumed to be nonsorbing in the NRC staff’s analysis). Table 3-12 provides 

estimates of peak daily intake for Mo for the one-million-year period in both present-day and 

cooler/wetter climates. The estimated daily intake of approximately 3 × 10−3

 parts per million is 

lower than the EPA Oral Reference Dose. 

For Middle Basin, radiological contaminants that contribute to estimated dose are limited to 

those elements whose transport in groundwater is not impacted by sorption processes. Tc-99 

and I-129 are the primary contributors to dose at Middle Basin, as at Furnace Creek springs. As 

groundwater flows to Middle Basin and evaporates, these elements are incorporated into the 

resulting evaporite mineral deposits. Table 3-13 summarizes the estimated peak annual doses 

for the Middle Basin area. All estimated doses are below 1 mrem [0.01 mSv], which is a small 

fraction of the dose from natural background levels of approximately 300 mrem/yr [3.0 mSv/yr] 

(including radon) for Amargosa Valley and much lower than the NRC annual dose standards for 

a Yucca Mountain repository in 10 CFR Part 63 {15 mrem [0.15 mSv] for the first 10,000 years, 

and 100 mrem [1 mSv] for one million years, after permanent closure}. 

Compared to the dose estimates for the Furnace Creek area, peak annual dose estimates for 

Middle Basin are lower for both climate states, primarily due to the absence of a drinking water 

pathway at this location. Table 3-14 provides estimates of peak daily intake for Mo for the 

one-million-year period in both present-day and future wetter climates at Middle Basin. The 

estimated value of daily intake (from inhalation and ingestion of wind-blown contaminated soil, 

as there is no drinking water pathway) is lower than the EPA Oral Reference Dose. The NRC 

staff concludes that the incremental impacts from radiological and nonradiological contaminants 

associated with natural groundwater discharges at Furnace Creek and Middle Basin would 

be SMALL. 

For Alkali Flat, the NRC staff did not calculate estimates of contaminants in the groundwater, 

and thus did not calculate concentrations in soils or potential doses to the public. There are no 

residents at Alkali Flat, and the potential exposure pathways are limited to inhalation and 

exposure to resuspended dust that may contain radiological and nonradiological contaminants 

precipitated from evaporating groundwater. The NRC staff observes that while the exposure 

pathways at Alkali Flat would be the same as those for Middle Basin, Alkali Flat is further from 

present population centers and has even fewer visitors or temporary occupants. Thus, the NRC 

staff concludes that the impacts at Alkali Flat would be a small fraction of those calculated for 

the other surface discharge locations and, thus, the incremental radiological and nonradiological 

public health impacts for Alkali Flat would be SMALL. 

Based on the information provided in Sections 4.4.1 and 4.4.2 concerning other actions, the 

NRC staff has identified only regional mining activity and NNSS tritium releases as additional 

actions or impacts that could contribute to cumulative public health impacts at these areas. 

Given its assessment of cumulative groundwater and cumulative soils impacts provided in the 

previous sections, and based on the NRC staff’s conclusions in Section 4.5.1 about DOE’s 

analysis of cumulative groundwater impacts from the NNSS and the Beatty disposal sites, the 

NRC staff concludes that the cumulative impacts on public health at these areas would be 
4-19 

nonexistent or would be so small as to not be detectable or not noticeably affect public health 

beyond the potential public health impacts from the repository alone. 

Ecological Resources at Natural Surface Discharge Locations 

As discussed in Section 3.2, the NRC staff evaluates the potential for nonhuman biota to be 

exposed to radionuclides at the State Line Deposits/Franklin Wells, Furnace Creek springs, 

Middle Basin, and Alkali Flat based on the estimated magnitude of radioactivity in the 

environment as quantified by the human dose estimates provided in Sections 3.1.1 and 3.1.2 for 

present-day and future wetter climates and for both 10,000-year and one-million-year 

timeframes. Because the human dose estimates are a small fraction of background radiation 

exposure, the NRC staff concludes in Section 3.2 that the estimated levels of radioactivity in the 

environment would be well below levels for potential impacts to nonhuman biota. 

The NRC staff also evaluates the potential for nonhuman biota to be exposed to potentially 

harmful levels of nonradiological chemicals based on the aquifer and soil concentrations in 

Sections 3.1.1 and 3.1.2 for present-day and future wetter climates and for both 10,000-year 

and one-million-year timeframes. The NRC staff compared the estimated aquifer and soil 

concentrations with ecological impact concentrations from available scientific data on the toxicity 

of the contaminant chemicals. Tables 3-16 and 3-17 compare estimated aquifer and soil 

concentrations at the State Line Deposits/Franklin Wells area and at Middle Basin and Furnace 

Creek, respectively, with ecological impact concentrations. The estimated water and soil 

concentrations of radiological and nonradiological contaminants at the State Line 

Deposits/Franklin Well area and Furnace Creek /Middle Basin are well below ecological impact 

concentrations, with the exception of Mo in the evaporite soil at Middle Basin. As discussed in 

Section 3.2, the evaporite soil at Middle Basin with the highest calculated Mo content 

corresponds to areas of sparse to no vegetation. This is because the high salinity in this soil is 

generally not conducive to plant growth. Therefore, the NRC staff concludes that it would be 

unlikely that a significant proportion of the diet for wildlife could be obtained from these areas, 

and that the actual exposure of local wildlife to Mo accumulated in soil would be negligible. 

Based on this analysis, the NRC staff concludes that the environmental impacts to nonhuman 

biota from radiological and nonradiological contaminants in these areas would be SMALL. 

Because only a very small fraction of the contaminants are expected to reach Alkali Flat 

(see Section 3.1.2.3), impacts on nonhuman biota at Alkali Flat would be much lower than 

impacts at the other discharge areas identified previously. In addition, the NRC staff expects 

that Alkali Flat would remain a predominantly playa environment with sparse amounts of 

salt-tolerant vegetation growing in highly saline surficial material. Thus, the NRC staff 

concludes that impacts to nonhuman biota at Alkali Flat would also be SMALL. 

Based on the information provided in Sections 4.4.1 and 4.4.2 concerning other actions, the 

NRC staff has identified only regional mining activity and NNSS tritium releases as additional 

actions or impacts that could contribute to cumulative ecological resources impacts at these 

areas. Given the NRC staff’s assessment of cumulative groundwater and cumulative soils 

impacts provided previously in this section, and based on the NRC staff’s conclusions in 

Section 4.5.1 about DOE’s analysis of cumulative groundwater impacts from the NNSS and the 

Beatty disposal sites, the NRC staff concludes that the cumulative impacts on ecological 

resources at the State Line Deposits/Franklin Wells, Furnace Creek springs and Middle Basin, 

and Alkali Flat would be minimal and not noticeably affect non-human biota beyond the potential 

impacts from the repository alone. 
4-20 

Historic and Cultural Resources at Natural Surface Discharge Locations 

Section 3.3 provides a discussion of the NRC staff’s review of DOE’s historic and cultural 

resources impact assessments in its EISs. The NRC staff concludes in Section 3.3.5 that DOE 

adequately addressed the potential impacts on historic and cultural resources in its EISs, given 

DOE’s defined region of influence and given that some consultation processes were still 

ongoing at the time the final 2008 SEIS was published. Based on the region of influence DOE 

described in its EISs as being limited to the Operator-Controlled Area, the NRC staff concludes 

that the surface discharge locations considered in this supplement are outside the region of 

influence DOE considered in its EISs. Thus, the NRC staff concludes that DOE would need to 

assess whether further consultation and investigation are necessary to account for potential 

impacts and potential cumulative impacts on historic and cultural resources that may be located 

in surface discharge areas. 

Environmental Justice at Natural Surface Discharge Locations 

Section 3.4.2 provides the NRC staff’s assessment of the potential for disproportionately high 

and adverse human health or environmental effects on minority and low-income populations in 

Death Valley National Park. Section 3.4.2 refers to the NRC staff’s assessment in 

Section 3.1.2.2 of the impacts at the Furnace Creek area and Middle Basin of Death Valley 

because only those areas are within an identified population center (Death Valley National 

Park). Therefore, this cumulative impacts analysis also assesses potential cumulative impacts 

only for the Furnace Creek and Middle Basin areas. Based on the information presented in 

Table 3-19, the NRC staff concludes that the minority population in the Death Valley Census 

County Division is a significant environmental justice population. The population in Death Valley 

is characterized in part by the Timbisha Shoshone Tribe on a parcel of land in the Furnace 

Creek area. The NRC staff acknowledges the sensitivities and cultural practices of the 

Timbisha Shoshone Tribe concerning the use and purity of springs in the Furnace Creek area. 

Based on the conclusions in Section 3.1.1 concerning impacts on groundwater, soils, and 

human health, the NRC staff found no environmental pathway that would affect minority or 

low-income populations differently from other segments of the general population; therefore, 

the NRC staff concludes that no disproportionately high and adverse health or 

environmental impacts would occur to minority or low-income segments of the population in the 

Death Valley area. 

Because the NRC staff has not identified environmental justice impacts in the Death Valley 

area, the NRC staff concludes that, likewise, no cumulative impacts related to environmental 

justice would occur in this area. 

4.6 Conclusion 

Cumulative impacts on groundwater and from surface discharges of groundwater include the 

potential impacts of the proposed repository when added to the aggregate effects of other past, 

present, and reasonably foreseeable future actions. As described in Chapter 3 of this 

supplement, the incremental impacts from the proposed repository on groundwater resources and 

from surface discharges of groundwater would be SMALL. The cumulative impacts from the 

proposed repository when added to other past, present, and reasonably foreseeable Federal and 

non-Federal activities, such as those activities at the NNSS, would also be SMALL.
5-1 

5 SUMMARY OF ENVIRONMENTAL CONSEQUENCES 

This report supplements the U.S. Department of Energy’s (DOE’s) 2002 Environmental Impact 

Statement (EIS) and 2008 Supplemental EIS (SEIS) for a proposed geologic repository for the 

disposal of spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada, by 

providing additional analyses of impacts on groundwater and from surface discharges of 

groundwater, as identified in the U.S. Nuclear Regulatory Commission (NRC) staff’s “Adoption 

Determination Report (ADR) for the U.S. Department of Energy’s Environmental Impact 

Statements for the Proposed Geologic Repository at Yucca Mountain” (NRC, 2008a). This 

chapter summarizes the impact conclusions from the NRC staff’s supplemental analyses and 

evaluates whether any of these supplemental analyses have identified any additional: 

(i) unavoidable adverse impacts, (ii) considerations regarding the relationship between local 

short-term uses of the environment and the maintenance and enhancement of long-term 

productivity, or (iii) irreversible and irretrievable commitments of resources. DOE previously 

summarized these impacts in Chapter 10 of its 2008 SEIS. 

The direct and indirect impacts of this supplement are described in Chapter 3 and the 

cumulative impacts are described in Chapter 4. As discussed in Chapter 1, and as applied 

throughout this supplement, significance categories for potential environmental impacts are 

based on NRC guidance (NRC, 2003) and are characterized as follows: 

SMALL—The environmental impacts are not detectable or are so minor that they will 

neither destabilize nor noticeably alter any important attribute of the resource. 

MODERATE—The environmental impacts are sufficient to alter noticeably, but not to 

destabilize, important attributes of the resource. 

LARGE—The environmental impacts are clearly noticeable and are sufficient to 

destabilize important attributes of the resource. 

Summary of Environmental Impacts 

This NRC staff supplement evaluates the direct, indirect, and cumulative impacts on water and 

soil, public health, ecology, historic and cultural resources, and environmental justice for 

locations beyond the postclosure compliance location. The locations of the affected 

environment are described in Chapter 2, which include potential locations for groundwater 

pumping and natural surface discharge beyond the postclosure compliance location 

downstream along the groundwater flow path to Death Valley. 

The NRC staff finds that all of the impacts on the resources evaluated in this supplement are 

SMALL. The NRC staff’s analysis includes the impact of potential radiological and 

nonradiological releases from the repository on the aquifer and at surface discharge locations of 

groundwater beyond the postclosure compliance location. The peak annual individual 

radiological dose at any of the evaluated locations is 1.3 mrem [0.013 mSv] from pumping and 

irrigation at the Amargosa Farms area. The NRC staff concludes that all estimated radiological 

doses are SMALL because they are a small fraction of background radiation dose of 

300 mrem/yr [3 mSv/yr] (including radon), and much lower than the NRC annual dose standards 

for a Yucca Mountain repository in title 10 of Code of Federal Regulations (CFR) Part 63 

{15 mrem [0.15 mSv] for the first 10,000 years, and 100 mrem [1 mSv] for one million years, 

after permanent closure}. The NRC staff’s peak dose estimates accounted for uncertainty in 

climate and in groundwater pumping at the Amargosa Farms area. Based on conservative 
5-2 

assumptions about the potential for health effects from exposure to low doses of radiation, the 

NRC staff expects that the estimated radiation dose would contribute only a negligible increase 

in the risk of cancer or severe hereditary effects in the potentially exposed population. Impacts 

to other resources at all of the affected environments beyond the postclosure compliance 

location from radiological and nonradiological (i.e., chemical) material from the repository would 

also be SMALL, based on low estimated levels of the evaluated constituents in those potentially 

affected areas. 

The cumulative impact analysis in Chapter 4 of this supplement contains the NRC staff’s 

evaluation of the cumulative impacts for direct and indirect impacts identified in Chapter 3 when 

aggregated with the impacts of other actions that could affect the same resources. The NRC 

staff also evaluates how its findings in Chapter 3 and cumulative impact findings in Chapter 4 

affect the conclusions provided by DOE in its assessment of cumulative impacts on 

groundwater in Chapter 8 of its EIS (DOE, 2002) and Chapter 8 of its SEIS (DOE, 2008a). 

Unavoidable Adverse Impacts 

Unavoidable adverse impacts are the direct, indirect, or cumulative impacts that remain after 

any proposed or required mitigation that could lessen impacts have been applied. The NRC 

staff considers the direct, indirect, and cumulative impacts summarized in the previous section 

to be the unavoidable adverse impacts of the proposed repository because the impact analyses 

have already taken into account applicable mitigating factors. 

Relationship between Short-term Uses of the Environment and the Maintenance and 

Enhancement of Long-Term Productivity 

The NRC staff considered whether its supplemental impact analyses identify any additional 

potential impacts of short-term uses on long-term productivity from what DOE previously 

evaluated in its EISs. Because there are no changes to the proposed action under review, the 

NRC staff concludes there are no changes to the short-term uses of the environment, as 

assessed in DOE’s EISs. Additionally, while this supplement considers potential repository 

impacts on the groundwater environment and from surface discharges along the groundwater 

flow path beyond the postclosure compliance location, the SMALL impact conclusions reached 

in this supplement entail no new and significant threats or contributions to the maintenance and 

enhancement of long-term productivity relative to the impacts previously described by DOE 

(2008a). 

Irreversible and Irretrievable Commitments of Resources 

The NRC staff considered whether this supplement identifies any additional irreversible and 

irretrievable commitments of resources. Because the analyses in this supplement do not 

change the proposed action or reveal any new and significant use or loss of finite resources, the 

NRC staff concludes that the supplement identifies no additional irreversible and irretrievable 

commitments of resources relative to the commitments that were previously described by DOE 

(2008a). 
6-1 

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Environmental Hazard?” California Agriculture. Vol. 46, No 6. pp. 18–21. 1992. 

Tanko, D.J. and P.A. Glancy. “Flooding in the Amargosa River Drainage Basin, 

February 23–24, 1998, Southern Nevada and Eastern California, including the Nevada Test 

Site.” ML15212A008. U.S. Geological Survey Fact Sheet 036-01. 4p. 2001. 

Taylor, T. “In the Office of the State Engineer, State of Nevada, Order 1197.” ML15212A009. 

Nov 4, 2008. Carson City, Nevada. 2008. 
6-13 

USCB. “Overview of Race and Hispanic Origin, 2010.” ML16113A141. Washington, DC: 

U.S. Census Bureau. 2010. 

USGS. “Southern Amargosa eMbedded Model (SAMM).” ML16116A326. U.S. Geological 

Survey project summary. 2016a. <http://nevada.usgs.gov/water/studyareas/samm.htm> 

(accessed April 25, 2016). 

_____. “Evaluating Source Water and Generalized Flow Paths to Lower Amargosa Valley, 

California. ML16116A329. U.S. Geological Survey Project Summary. 2016b. 

<http://nevada.usgs.gov/water/studyareas/LAV.htm> (accessed April 25, 2016). 

Winograd, I.J. and W. Thordarson. “Hydrogeologic and Hydrochemical Framework, 

South-Central Great Basin, Nevada-California, With Special Reference to the Nevada Test 

Site.” U.S. Geological Survey Professional Paper 712–C. 126p. 1975. 

Winterle, J.R. “Simulation of Spring Flows South of Yucca Mountain, Nevada, Following a 

Potential Future Water Table Rise.” ML052630242. San Antonio, Texas: Center for Nuclear 

Waste Regulatory Analyses. 2005. 

Zdon and Associates. “Technical Review Summary—Draft Supplement to U.S. Department of 

Energy’s Environmental Impact Statement for the Proposed Nuclear Fuel and High-Level 

Radioactive Waste Repository at Yucca Mountain, Nevada.” ML15342A025. Attachment 2 of 

Inyo County comments November 11, 2015. 2015. 

Zdon, A., M.L. Davisson, and A.H. Love. “Testing the Established Hydrogeologic Model of 

Source Water to the Amargosa River Basin, Inyo and San Bernardino Counties, California, 

Environmental Forensics, 16:4, 344-355.” DOI: 10.1080/15275922.2015.1091406. 2015. 

Zdon and Associates. “2014 State of the Basin Report: Amargosa River Basin, Inyo and 

San Bernardino Counties, California and Nye County Nevada.” ML16104A277, ML16104A288. 

The Nature Conservancy. 2014. 

7-1 

7 GLOSSARY 

Accessible environment: For this analysis, any point outside of the long-term controlled area 

of the repository at Yucca Mountain, including the atmosphere above the controlled area, land 

surface, and surface waters along the Yucca Mountain flow path. The specific definition used 

by the NRC for regulation of the repository at Yucca Mountain is given in 10 CFR 63.302. 

Adsorption: The adhesion by chemical or physical forces of molecules or ions (of gases or 

liquids) to the surface of solid bodies. For example, the transfer of solute mass, such as 

radionuclides, in groundwater to the solid geologic surfaces with which it comes in contact. The 

term sorption is sometimes used interchangeably with this term. 

Advection: The process in which solutes, particles, or molecules are transported by the motion 

of flowing fluid. 

Alloy 22: A nickel-based, corrosion-resistant alloy containing approximately 22 weight percent 

chromium, 13 weight percent molybdenum, and 3 weight percent tungsten as major alloying 

elements. This alloy is used as the outer container material in U.S. Department of Energy’s 

waste package design for the repository at Yucca Mountain, Nevada. 

Alluvial sediments, alluvial fan: Pertaining to the process of moving sediment by running 

water. An alluvial fan is a wedge-shaped sedimentary deposit of alluvium formed at the base of 

a slope in arid regions. 

Aquifer: An underground layer of permeable, unconsolidated sediments or porous or fractured 

bedrock that yields usable quantities of water to a well or spring. 

Biosphere: The regions of the surface, atmosphere, and waters of the earth occupied by 

living organisms.

Biosphere dose conversion factor: For purposes of this analysis, the factor that is used to 

convert the concentration of radiological contaminants in groundwater to calculate the annual 

dose to the reasonably maximally exposed individual, or other receptor with similar 

characteristics, due to a specific radionuclide. 

Biota: The living organisms of a geographic region or time period considered as a group. 

Carbonate rock: Rocks composed primarily of calcium or magnesium carbonate minerals, 

most commonly, limestone or dolomite. Carbonate rocks underlie extensive portions of the 

Great Basin in Nevada and the Death Valley regional groundwater flow system. 

Colloid: As applied to radionuclide migration, colloids are large molecules or very small 

particles, having at least one dimension with the size range of 10−6

 to 10−3 mm [10−8 to 10−5 in] 

that are suspended in a solvent. Colloids in groundwater arise from clay minerals, organic 

materials, or (in the context of a proposed geologic repository) from corrosion of 

engineered materials. 

Confining unit: In geology, a confining unit is a rock or sediment unit of relatively low 

permeability that retards the movement of water in or out of adjacent aquifers. 
7-2 

Contaminants: In this analysis, materials that could be released from the repository into the 

groundwater and could impact water quality. These include both radiological and 

nonradiological materials. 

Corrosion: The deterioration of a material, usually a metal, as a result of a chemical or 

electrochemical reaction with its environment. Corrosion includes, but is not limited to, general 

corrosion, microbially influenced corrosion, localized corrosion, galvanic corrosion, and stress 

corrosion cracking. 

Cultural resource (historic resource): The remains of past human activity, including 

prehistoric era and historic era archaeological sites, historic districts, buildings, or objects with 

an associated historical, cultural, archaeological, architectural, community, or aesthetic value. 

Historic and cultural resources also include traditional cultural properties that are important to a 

living community of people for maintaining their culture. 

Death Valley Regional groundwater Flow System model (DVRFS model): A model of 

groundwater conditions and flow for the Death Valley region developed by the U.S. Geological 

Survey. The model can simulate steady-state groundwater conditions with no withdrawal by 

pumping, as well as different pumping rates over time. 

Decay (radioactive): The process by which a radionuclide spontaneously transforms into 

another element, called a decay product. That decay product may undergo further decay. 

Discharge (surface): The areas where groundwater leaves the ground. Discharge points 

typically occur as springs or seepage into wetlands, lakes, and streams. Discharge also occurs 

as evapotranspiration. 

Dose: A general term that may be used to refer to the amount of energy absorbed by an object 

or person per unit mass. Known as the “absorbed dose,” this reflects the amount of energy that 

ionizing radiation sources deposit in materials through which they pass, and is measured in 

units of radiation-absorbed dose (rad). The related international system unit is the gray (Gy), 

where 1 Gy is equivalent to 100 rad. 

Evaporite: Geologic deposits composed of water-soluble mineral sediments that result from 

the evaporation of surface water. 

Evapotranspiration: The loss of water by evaporation from the soil and other surfaces, 

including evaporation of moisture emitted or transpired from plants. 

Flux: The amount of fluid (or mass) that flows through a unit area per unit time. 

Geologic repository: An excavated, underground facility that is designed, constructed, and 

operated for safe and secure permanent disposal of high-level radioactive waste. A geologic 

repository uses an engineered barrier system and a portion of the site's natural geology, 

hydrology, and geochemical systems to isolate the radioactivity of the waste. 

Groundwater: The water found beneath the Earth’s surface, usually in porous rock formations 

(aquifers) or in a zone of saturation, which may supply wells and springs, as well as base flow to 

major streams and rivers. Generally, it refers to all water contained in the ground. 
7-3 

Half-life: The time in which one-half of the atoms of a particular radioactive substance 

disintegrate into another nuclear form. Measured half-lives vary from millionths of a second to 

billions of years. Also called physical or radiological half-life. 

Hydraulic gradient (groundwater): The rate of change of hydraulic head per unit of distance 

of flow at a given point and in a given direction; the measure of steepness between two or more 

hydraulic head measurements over the length of a flow path. For this analysis, the hydraulic 

gradient is used to determine the direction and rate of groundwater movement. 

Hydraulic head (groundwater): The height to which water would rise in an open well 

expressed in units of length, as a measure of water pressure above a reference elevation. For 

an unconfined aquifer, the hydraulic head at a location coincides with the water table elevation. 

Hydraulic head measurements over a region determine the potentiometric surface. 

Hydrology: The study of water that considers its occurrence, properties distribution, circulation, 

and transport, and includes groundwater, surface water, and rainfall. 

Infiltration: For this analysis, infiltration is the precipitation or irrigation water that is not lost to 

evapotranspiration or runoff and enters the groundwater system. 

Latent cancer fatality: A death that results from cancer caused by ionizing radiation following 

a latent, or dormant, period between the time of a radiation exposure and the time the cancer 

cells become active. 

Longitudinal dispersion: The mixing of groundwater and contaminants in the direction of 

groundwater flow as water flows in an aquifer. Dispersion is the process whereby some of the 

contaminants travel at a different rate than the average velocity of the water. 

Low-income populations: Persons whose average family income is below the poverty line. 

The poverty line takes into account family size and age of individuals in the family. In 2013, the 

poverty line for a family of four with two children below the age of 18 was $23,624. For any 

family below the poverty line, all family members are considered to be below the poverty line. 

Low-level radioactive waste (LLRW): A general term for a wide range of items that have 

become contaminated with radioactive material or have become radioactive through exposure 

to neutron radiation. The radioactivity in these wastes can range from just above natural 

background levels to much higher levels, such as those observed in parts from inside the 

reactor vessel in a nuclear power reactor.

Matrix diffusion: The exchange between the fast-flowing groundwater in fractures and faults 

with slow-flowing water in the rock matrix. 

Nonradiological contaminants: Contaminants that could be released from the proposed 

repository after permanent closure, including chemically toxic metals such as molybdenum, 

nickel, and vanadium. These materials generally originate from construction materials of the 

repository and the waste packages. Uranium, while a radioactive element, is also evaluated for 

its chemical toxicity as a nonradiological contaminant. 

Playa: A dry lake bed at the bottom of a desert basin, sometimes temporarily covered with 

water. Playas have little or no vegetation, and are highly saline (salty) due to evaporation of 

groundwater near or at the ground surface. This leads to precipitation of salt minerals. 
7-4 

Potentiometric surface: A hypothetical surface representing the level to which groundwater 

would rise if not trapped in a confined aquifer. The potentiometric surface is equivalent to the 

water table in an unconfined aquifer. 

Radioactivity: The property possessed by some elements (e.g., uranium) of spontaneously 

emitting energy in the form of radiation as a result of the decay (or disintegration) of an unstable 

atom. Radioactivity is also the term used to describe the rate at which radioactive material 

emits radiation. Radioactivity is measured in curies (Ci) and becquerels (Bq). 

Radionuclide: An unstable isotope of an element that decays or disintegrates spontaneously, 

thereby emitting radiation. Approximately 5,000 natural and artificial radioisotopes have been 

identified. 

Radiological contaminants: Radionuclide contaminants that could be released from the 

proposed repository after permanent closure. 

Radioactive decay and ingrowth: The decay of radioactive material over time, which in turn 

may generate new radioactive contaminants (daughter products). The rate of decay and 

daughter products depend on the type of radioactive material. 

Recharge (groundwater): Water entering an aquifer where permeable soil or rock allows 

water to enter the ground and reach groundwater. 

Saturated zone: The subsurface ground area where water fills all of the openings (pores) in 

the soil or rock. Water that seeps deep into the ground continues downward under the force of 

gravity until it reaches this area. 

Sorption: The binding, on a microscopic scale, of one substance to another. Sorption is a term 

that includes both adsorption and absorption and refers to the binding of dissolved radionuclides 

onto geologic solids or waste package materials by means of close-range chemical or physical 

forces. Sorption is a function of the chemistry of the radioisotopes, the fluid in which they are 

carried, and the material they encounter along the flow path. 

Sorption coefficient: A numerical means to represent how strongly one substance sorbs to 

another. 

Specific discharge: In hydrology, the rate of discharge of groundwater per unit area of a 

porous medium measured normal to the direction of flow. Synonymous with Darcy velocity. 

Steady state (groundwater): That point when all input rates to a groundwater system are 

balanced by all the output rates. 

Unsaturated zone: The zone between the land surface and the regional water table. 

Water table: The upper limit of the saturated zone (the portion of the ground wholly saturated 

with water). The upper surface of a zone of saturation above which the majority of pore spaces 

and fractures are less than 100 percent saturated with water most of the time (unsaturated 

zone) and below which the opposite is true (saturated zone).
8-1 

8 LIST OF PREPARERS 

Contributors to the preparation of this supplement include staff from the U.S. Nuclear 

Regulatory Commission (NRC), staff from the Center for Nuclear Waste Regulatory Analyses 

[(CNWRA®), a Federally Funded Research and Development Center for the NRC of Southwest 

Research Institute® (SwRI®)], and a CNWRA consultant. Each person’s role, education, and 

experience are outlined below. 

8.1 NRC Contributors 

Randall Fedors: Hydrology, Geology, Geochemistry 

M.S., Civil Engineering, Colorado State University, 1991 

M.S., Geology, University of Minnesota, 1983 

B.A., Geology, Carleton College, 1979 

Years of Experience: 34 

Jin-Ping Gwo: Hydrology, Performance Assessment, Contaminant Transport 

Ph.D., Civil Engineering, Pennsylvania State University, 1992 

M.S., Civil Engineering, University of California, Berkeley, 1989 

B.S., Civil Engineering, National Chiao-Tung University, 1985 

Years of Experience: 27 

Timothy McCartin: Radionuclide Flow and Transport, Performance Assessment 

M.S., Physics, Wayne State University, 1976 

B.S., Physics, Xavier University, 1973 

Years of Experience: 42 

Christine Pineda: Cumulative Impacts; Historic and Cultural Resources; Environmental Justice 

M.S., Environmental Sciences and Policy, Johns Hopkins University, 2000 

B.A., Sociology, and Certificate, Environmental Studies, Dickinson College, 1993 

Years of Experience: 22 

James Rubenstone: Geology, Geochemistry 

Ph.D., Geological Sciences, Cornell University, 1984 

B.S., Geology, College of William and Mary, 1976 

Years of Experience: 39 

Stephen Self: Geology/Earth Sciences, Volcanology 

 Ph.D., Geology, Volcanology, Imperial College, University of London, UK, 1974 

 B.Sc., Earth Sciences, Leeds University, UK, 1970 

 Years of Experience: 45 

8.2 CNWRA Contributors 

Paul Bertetti: Geochemistry, Water Resources 

 M.S., Geology, University of Texas at San Antonio, 1999 

 B.S., Geology, University of Texas at San Antonio, 1991 

 Years of Experience: 22 
8-2 

Miriam Juckett: Principal Investigator; Public Outreach; Cumulative Impacts 

M.S., Environmental Sciences, University of Texas at San Antonio, 2006 

B.S., Chemistry, University of Texas at San Antonio, 2003 

Years of Experience: 13 

Patrick LaPlante: Public and Occupational Health and Safety; Cumulative Impacts 

M.S., Biostatistics and Epidemiology, Georgetown University, 1994 

B.S., Environmental Studies, Western Washington University, 1988 

Years of Experience: 26 

Amy Minor: Ecological Resources; Environmental Justice; Socioeconomics 

B.A., Environmental Studies, University of Kansas, 1998 

Years of Experience: 15 

Olufemi Osidele: Olufemi Osidele: Hydrology, Water Resources 

 Ph.D., Environmental Systems Analysis, University of Georgia, 2001 

 M.Sc., Hydrology, University of London, 1992 

 B.Sc., Civil Engineering, Obafemi Awolowo University, 1987 

 Years of Experience: 29 

David Pickett: Project Manager; Performance Assessment; Geochemistry 

 Ph.D., Geology, California Institute of Technology, 1991 

 M.S., Geology, California Institute of Technology, 1984 

 B.A., Geology, Rice University 1982 

 Years of Experience: 22 

Deborah Waiting: GIS Analyst 

B.S., Geology, University of Texas at San Antonio, 1999 

Years of Experience: 16 

8.3 CNWRA Consultant 

Roland Benke: Public and Occupational Health and Safety 

Ph.D., Nuclear Engineering, University of Michigan, 2000 

M. Eng., Radiological Health Engineering, University of Michigan, 1996 

B.S., Nuclear Engineering, University of Michigan, 1994 

Years of Experience: 20 
9-1 

9 DISTRIBUTION LIST 

The U.S. Nuclear Regulatory Commission (NRC) is providing copies of this supplement to the 

organizations and individuals listed as follows. NRC will provide copies to other interested 

organizations and individuals upon request. 

John Kotek 

U.S. Department of Energy 

William Boyle 

U.S. Department of Energy 

Mary Louise Wagner 

U.S. Department of Energy 

Marthea Rountree 

U.S. Environmental Protection Agency 

Brian Lusher 

Advisory Council on Historic Preservation 

Rebecca Palmer 

Nevada State Historic Preservation Office 

Julianne Polanco 

California State Historic Preservation Office 

Michael Reynolds 

Death Valley National Park 

Charles J. Fitzpatrick 

Egan, Fitzpatrick, Malsch & Lawrence, PLLC 

John W. Lawrence 

Egan, Fitzpatrick, Malsch & Lawrence, PLLC 

Martin G. Malsch 

Egan, Fitzpatrick & Malsch, PLLC 

Robert Halstead, Executive Director 

Nuclear Waste Project Office 

Nevada Agency for Nuclear Projects 

Brian W. Hembacher 

Deputy Attorney General 

California Attorney General’s Office 

Timothy E. Sullivan 

Deputy Attorney General 

California Department of Justice 
9-2 

Kevin W. Bell 

Senior Staff Counsel 

California Energy Commission 

Donald J. Silverman 

Morgan, Lewis & Bockius, LLP 

Thomas C. Poindexter 

Morgan, Lewis & Bockius, LLP 

Alex S. Polonsky 

Morgan, Lewis & Bockius, LLP 

Lewis Csedrik 

Morgan, Lewis & Bockius, LLP 

Raphael P. Kuyler 

Morgan, Lewis & Bockius, LLP 

Susan L. Durbin 

Deputy Attorney General, CA 

Ross D. Colburn 

Fredericks Peebles & Morgan, LLP 

Martha S. Crosland 

U. S. Department of Energy 

Angela M. Kordyak 

U. S. Department of Energy 

Nicholas P. DiNunzio 

U. S. Department of Energy 

James Bennett McRae 

U. S. Department of Energy 

Malachy R. Murphy 

Nye County, Nevada 

George W. Hellstrom 

U.S. Department of Energy 

Office of the General Counsel 

Robert M. Andersen 

Akerman Senterfitt, LLP 

Frank A. Putzu, Counsel, Naval Reactors 

Naval Sea Systems Command 

John M. Peebles 

Fredericks Peebles & Morgan, LLP 
9-3 

Darcie L. Houck 

Fredericks Peebles & Morgan, LLP 

Elizabeth A. Vibert, District Attorney 

Clark County, Nevada 

Ellen C. Ginsberg 

Nuclear Energy Institute, Inc. 

Anne W. Cottingham 

Nuclear Energy Institute, Inc. 

Jerry Bonanno 

Nuclear Energy Institute, Inc. 

David A. Repka 

Winston & Strawn, LLP 

William A. Horin 

Winston & Strawn, LLP 

Jay E. Silberg 

Pillsbury Winthrop Shaw Pittman, LLP 

Timothy J.V. Walsh 

Pillsbury Winthrop Shaw Pittman, LLP 

Gregory L. James 

Inyo County, California 

Robert F. List 

Kolesar & Leathman 

Jason M. Bacigalupi 

Kolesar & Leathman 

Diane Curran 

Harmon, Curran, Spielberg, & Eisenberg, LLP 

Ian Zabarte, Board Member 

Native Community Action Council 

Curtis G. Berkey 

Alexander, Berkey, Williams, & Weathers, LLP 

Scott W. Williams 

Alexander, Berkey, Williams, & Weathers, LLP 

Rovianne A. Leigh 

Alexander, Berkey, Williams, & Weathers, LLP 
9-4 

Bret O. Whipple 

Lincoln County, Nevada 

Daniel Hooge, District Attorney 

Lincoln County, Nevada 

Andrew A. Fitz 

State of Washington 

Office of the Attorney General 

H. Lee Overton 

State of Washington 

Office of the Attorney General 

Jonathan C. Thompson 

State of Washington 

Office of the Attorney General 

Todd R. Bowers 

State of Washington 

Office of the Attorney General 

Connie Simkins 

Lincoln County, Nevada 

Kenneth P. Woodington 

Davidson & Lindemann, PA 

Thomas R. Gottshall 

Haynesworth Sinkler Boyd, PA 

S. Ross Shealy 

Haynesworth Sinkler Boyd, PA 

Mike Baughman 

Intertech Services Corporation 

Michael Berger 

Attorney for the County of Inyo 

Robert S. Hanna 

Attorney for the County of Inyo 

Philip R. Mahowald 

Prairie Island Indian Community 

James Bradford Ramsay 

National Association of Regulatory Utility Commissioners 

Don L. Keskey 

Public Law Resource Center, PLLC 
9-5 

Christopher B. Clare 

Clark Hill PLC 

Marta Adams, Chief Deputy Attorney General 

Bureau of Government Affairs 

Nevada Attorney General 

Steve Frishman, Tech. Policy Coordinator 

Nevada Agency for Nuclear Projects 

Nuclear Waste Project Office 

Celeste Sandoval, Quality Assurance 

Records Specialist 

Nye Co. Nuclear Waste Repository Project Office 

Theodore Beutel, District Attorney 

Eureka County Office of the District Attorney 

Abigail Johnson 

Nuclear Waste Advisory for Eureka County 

Loreen Pitchford 

NWOP Consulting, Inc. 

Ronald Damele, Director 

Eureka County Public Works 

Tara Baugh 

Armstrong Teasdale, LLP 

Edwin Mueller, Director 

Esmeralda County Repository Oversight Program 

Linda Mathias, Director 

Mineral County Nuclear Projects Office 

Cathreen Richards, Senior Planner 

Inyo Co Yucca Mountain Repository Assessment Office 

George Gholson, Chairman 

Timbisha Shoshone Tribal Council 

Editor 

Indian Country Today 

Daryl Crawford 

Inter-Tribal Council of Nevada 

Loreen Pitchford 

Yucca Mountain Public Reading Room 

in Churchill County 
9-6 

Annelle Watts 

Yucca Mountain Public Reading Room 

in Eureka County 

George McCorkell 

Yucca Mountain Public Reading Room 

in Esmerelda County 

Irene Navis 

Yucca Mountain Public Reading Room 

in Clark County 

Linda Mathius 

Yucca Mountain Public Reading Room 

in Mineral County 

Connie Simkins 

Yucca Mountain Public Reading Room 

in Lincoln County 

Jan Morrison 

Yucca Mountain Public Reading Room 

in Lander County 

Elizabeth Enriquez 

Yucca Mountain Public Reading Room 

in Nye County 

Skip Canfield 

Yucca Mountain Public Reading Room 

Nevada Division of State Lands 

Connie Lusedo 

Yucca Mountain Public Reading Room 

State of Nevada State Clearinghouse 

Susie Skarl 

Yucca Mountain Public Reading Room 

 at the University of Nevada, Las Vegas 

Patrick Ragains 

Yucca Mountain Public Reading Room 

 at the University of Nevada, Reno 

Claire Whetsel 

Las Vegas Yucca Mountain Science Center 
9-7 

John Pawlak 

Pahrump Yucca Mountain Science Center 

Marina Anderson 

Beatty Yucca Mountain Science Center

10-1 

10 INDEX 

Adoption Determination Report (ADR), iii, 

xi, xiii, 1-1, 1-2, 1-5, 2-7, 3-1, 3-3, 3-4, 

3-6, 3-33, 3-34, 3-35, 3-36, 4-1, 4-2, 5-1, 

6-10, A–2, A–3, B–7, B–8, B–9, B–10, 

B–11, B–12, B–13, B–14, B–15, B–16, 

B–17, B–22, B–23, B–28, B–29, B–32, 

B–33, B–36, B–37, B–38, B–40, B–42, 

B–43, B–44, B–45, B–46, B–47, B–55, 

B–56, B–58, B–61, B–62, B–63, B–65, 

B–67, B–69, B–70, B–73, B–76, B–77, 

B–79, B–81, B–84, B–85, B–86, B–87, 

B–88, B–89, B–91, B–93, B–94, B–96, 

B–97, B–99, B–100, B–101, B–102, 

B–103, B–104, B–105, B–106, B–107, 

B–108, B–109, B–110, B–111 

agriculture, 2-15, 2-16, 3-16, 3-17, 3-25, 

3-39, A–14, A–16, A–17, A–18, B–33, 

B–48, B–54, B–64, B–71, B–83, B–84 

Alkali Flat, 2-7, 2-8, 2-11, 2-12, 2-14, 2-15, 

2-20, 2-22, 2-23, 2-25, 2-26, 2-28, 2-32, 

3-2, 3-3, 3-14, 3-15, 3-30, 3-33, 4-10, 

4-15, 4-16, 4-17, 4-18, 4-19, A–2, A–9, 

A–15, A–19, A–20, B–51, B–52, B–53, 

B–57, B–60 

alluvial, iii, xi, 1-3, 2-1, 2-5, 2-9, 2-11, 2-14, 

2-15, 2-19, 2-20, 2-22, 2-23, 2-25, 2-27, 

2-30, 3-8, 3-11, 3-16, 3-17, 3-22, 4-3, 4-4, 

7-1, A–9, A–11, A–12, B–41, B–50, B–51, 

B–52, B–53, B–59, B–61, B–67 

Ash Meadows, 2-7, 2-11, 2-14, 2-16, 2-20, 

2-23, 2-25, 2-26, 2-27, 2-28, 3-16, 3-18, 

3-30, 4-10, 6-3, 6-8, A–15, A–20, B–52, 

B–53, B–54, B–55, B–66, B–67, B–75, 

B–76, B–95 

Beatty, 2-20, 4-4, 4-5, 4-8, 4-9, 4-10, 4-12, 

4-13, 4-14, 4-16, 4-17, 4-18, 4-19, 6-9, 

9-7, B–48, B–90, B–91, B–92 

biosphere, vii, 1-4, 2-4, 2-31, 3-12, 3-16, 

3-21, 3-25, 3-39, 4-3, 6-11, 6-12, 7-1, 

A–1, A–16, A–17, A–18, A–19, A–20, 

B–38 

biota, 3-31, 3-33, 4-14, 4-19 

Bureau of Land Management (BLM), xiii, 

2-11, 2-30, 4-6, 4-7, 4-8, 6-2, 6-3, 6-4, 

6-7, B–30, B–67, B–93, B–94, B–95, 

B–115 

carbonate, 2-5, 2-6, 2-7, 2-11, 2-12, 2-14, 

2-19, 2-22, 2-25, 2-26, 2-27, 2-30, 3-17, 

3-22, 4-4, 7-1, A–9, A–14, A–15, A–20, 

B–51, B–52, B–55, B–56, B–59, B–65, 

B–67, B–76 

Clark County, 9-3, 9-6, B–62, B–94, B–117 

climate change, xi, 1-4, 2-18, 2-21, 2-31, 

2-33, A–3, A–12, B–30, B–34, B–105 

climate state, vii, xi, 1-4, 2-17, 2-18, 2-21, 

2-31, 2-32, 2-33, 3-2, 3-6, 3-7, 3-10, 3-11, 

3-14, 3-17, 3-18, 3-21, 3-22, 3-24, 3-26, 

3-27, 3-28, 3-29, 3-30, 3-31, 3-38, 4-3, 

4-16, 4-18, A–4, A–12, A–18, A–19, 

B–15, B–30, B–34, B–37 

Council on Environmental Quality (CEQ), 

xiii, 1-4, 3-34, 4-2, 4-3, 6-3, B–13, B–24, 

B–31, B–35, B–92 

Crater Flat, 2-27 

cultural resources, 2-21, 2-22, 3-1, 3-33, 

3-34, 3-35, 4-3, 4-11, 4-20, 5-1, 7-2, 8-1, 

B–3, B–12, B–13, B–77, B–78, B–79, 

B–81, B–98 

Death Valley Regional Groundwater Flow 

System (DVRFS), vii, xiii, 2-1, 2-2, 2-5, 

2-6, 2-7, 2-8, 2-12, 2-13, 2-15, 2-16, 2-17, 

2-18, 2-24, 2-26, 2-28, 2-29, 2-30, 2-31, 

3-6, 3-14, 3-30, 6-2, 6-6, 6-12, 7-2, A–7, 

A–9, A–11, A–12, B–37, B–49, B–50, 

B–51, B–52, B–53, B–54, B–55, B–56, 

B–59, B–60 

Devils Hole, 2-11, 2-16, 2-28, 2-30, 2-33, 

3-16, B–34, B–54, B–55, B–65, B–75, B–

76 

ecology, iii, xii, 2-20, 3-1, 5-1, 6-9, A–14, 

B–51, B–75, B–77 
10-2 

endangered species, 2-16, B–75, B–76, 

B–77 

environmental justice, 3-1, 3-36, 3-37, 

4-3, 4-11, 4-14, 4-20, 5-1, 6-1, 8-1, 8-2, 

B–3, B–71, B–79, B–80, B–81, B–82, 

B–98 

Environmental Protection Agency (EPA), 

xiii, 1-4, 2-4, 2-31, 3-5, 3-10, 3-11, 3-12, 

3-14, 3-15, 3-18, 3-20, 3-22, 3-24, 3-26, 

3-28, 3-31, 3-32, 4-2, 4-3, 4-11, 4-12, 

4-13, 4-17, 4-18, 6-5, 6-6, 6-9, 6-11, 9-1, 

A–4, A–16, B–27, B–36, B–43, B–57, 

B–62, B–69, B–72, B–73, B–75, B–114 

Esmeralda County, 2-4, 3-36, 9-5 

evaporite, 3-17, 3-18, 3-21, 3-23, 3-24, 

3-25, 3-26, 3-30, 3-31, 3-33, 3-39, 4-16, 

4-18, 4-19, A–15, A–16, A–18, A–19, 

A–20, A–21, B–41 

Fortymile Canyon, Fortymile Wash, iii, xi, 

2-1, 2-7, 2-9, 2-11, 2-27, 2-31, 3-11, 3-16, 

3-17, 3-30, 4-15, 6-2, A–16, A–20, B–49, 

B–50, B–51, B–52, B–55, B–56, B–58, 

B–63 

Franklin Lake, 2-12, 2-23, 2-28, 6-4, A–15, 

B–52 

Franklin Well, ix, 2-11, 2-20, 2-23, 2-25, 

3-2, 3-14, 3-15, 3-16, 3-17, 3-18, 3-19, 

3-20, 3-31, 3-32, 3-33, 3-39, 4-15, 4-16, 

4-17, 4-19, A–13, A–18, B–41, B–63 

Funeral Mountains, 2-7, 2-8, 2-12, 2-14, 

2-15, 2-22, 2-25, 2-27, 3-22, 4-7, 6-3, 6-7, 

A–9, A–20, B–50, B–51, B–52, B–53, 

B–59, B–63 

Furnace Creek Basin, 2-7, 2-11, 4-10 

Furnace Creek springs, 2-12, 2-14, 2-20, 

2-22, 2-31, 2-32, 3-37, 4-15, 4-16, 4-17, 

4-18, 4-19, A–18, A–20, B–51, B–54, 

B–57, B–59, B–60, B–63, B–98 

Great Basin, 2-5, 2-17, 2-19, 2-21, 6-3, 6-5, 

6-8, 6-9, 6-11, 6-13, 7-1, B–67, B–86, 

B–94, B–120 

greenhouse gases, 1-4, 2-18, B–30, 

B–105 

habitat, 2-20, 3-30 

hazardous (chemicals, constituents, 

waste), 4-4, 4-7, 4-9, 4-10, B–61, B–91 

high-level radioactive waste (HLW), iii, xi, 

xiii, 1-1, 1-5, 2-21, 3-35, 4-4, 4-5, 5-1, 6-1, 

6-3, 6-4, 6-5, 6-8, 6-13, 7-2, B–1, B–44, 

B–63, B–93, B–95, B–102, B–104 

historic, 2-12, 2-21, 2-22, 3-33, 3-34, 3-35, 

4-8, 4-20, 5-1, 7-2, B–13, B–77, B–78, 

B–79, B–81, B–94 

human health, 3-1, 3-5, 3-36, 3-37, 3-38, 

3-40, 4-13, 4-14, 4-20, B–13, B–27, B–72, 

B–73, B–79, B–81, B–82, B–92, B–98, 

B–99, B–103 

Inyo County, 2-3, 2-4, 2-12, 3-36, 3-37, 

3-38, 6-3, 6-4, 6-7, 6-8, 6-13, 9-3, 9-4, 9-

5, B–51, B–63, B–84, B–91, B–116, B–

117 

Lincoln County, 2-4, 3-36, 6-3, 6-9, 6-10, 

9-4, 9-6, B–7, B–9, B–20, B–21, B–50, 

B–51, B–62, B–63, B–66, B–94, B–119 

low-level radioactive waste (LLW), xiii, 

4-4, 4-5, 4-7, 4-10, B–89 

mass flux, 3-4, 3-6, 3-8, 3-9, 3-10, 3-21, 

3-22, A–2, A–5, A–6, A–7, A–10, B–36, 

B–58, B–59, B–61 

mining, 2-16, 2-31, 4-4, 4-5, 4-6, 4-8, 4-11, 

4-12, 4-13, 4-14, 4-16, 4-17, 4-18, 4-19, 

B–84, B–93, B–94 

mitigate, mitigation, 3-34, 4-8, 4-13, 5-2, 

B–24, B–28, B–61, B–79, B–90, B–93, 

B–94, B–99, B–108 

Mojave, 2-20, 2-21, 2-26, 6-3, 6-4, 6-11 
10-3 

National Environmental Policy Act 

(NEPA), xiii, 1-1, 1-5, 3-34, 3-36, 4-1, 4-2, 

4-3, 6-3, 6-6, B–3, B–4, B–7, B–10, B–11, 

B–12, B–13, B–15, B–17, B–18, B–19, 

B–20, B–21, B–22, B–23, B–24, B–27, 

B–28, B–29, B–30, B–35, B–48, B–49, 

B–71, B–92, B–112 

Nevada National Security Site (NNSS), 

xiii, 2-1, 2-2, 2-9, 2-30, 4-4, 4-5, 4-6, 4-7, 

4-9, 4-10, 4-11, 4-12, 4-13, 4-14, 4-16, 

4-17, 4-18, 4-19, 4-20, 6-1, 6-4, B–36, 

B–64, B–65, B–66, B–67, B–68, B–69, 

B–89, B–90, B–91, B–92, B–93, B–94, 

B–95, B–96, B–103, B–108, B–112 

Nevada Test Site (NTS), 2-2, 4-4, 6-12, 

6-13, B–65, B–68, B–89, B–90, B–103 

Nye County, iii, xi, 1-1, 2-3, 2-4, 2-5, 2-9, 

2-16, 2-28, 3-36, 3-37, 3-38, 6-1, 6-2, 6-4, 

6-5, 6-8, 6-9, 6-10, 6-13, 9-2, 9-5, 9-6, 

B–1, B–56, B–57, B–62, B–63, B–66, 

B–83, B–94, B–117, B–119 

Oral Reference Dose, 3-5, 3-14, 3-15, 

3-19, 3-20, 3-26, 3-28, 3-30, 4-13, 4-17, 

4-18, A–16, B–27 

Pahrump, 2-15, 2-16, 4-8, 6-2, 6-3, 6-10, 

9-7, B–94, B–117 

Pahute Mesa-Oasis Valley, 2-7, 4-10 

paleospring, 2-25, 3-16, 3-17, 3-33, 4-15, 

A–14, B–51 

Penoyer Valley, 2-16 

programmatic agreement, 2-21, 3-33, 

3-34, 3-35, 6-5, B–12, B–13, B–78, B–80 

public health, iii, xii, 3-12, 3-14, 3-18, 3-20, 

3-25, 3-28, 3-30, 3-37, 3-39, 4-3, 4-11, 

4-13, 4-14, 4-17, 4-18, 5-1, B–28, B–35, 

B–61, B–64, B–69, B–71, B–75, B–92, 

 B–98, B–103, B–111, B–120 

reasonably maximally exposed 

individual (RMEI), xiii, 2-1, 3-1, 3-2, 3-5, 

3-6, 3-7, 3-12, 3-14, 4-9, 7-1, A–1, A–16, 

A–20, B–31, B–33, B–47, B–48, B–71, 

B–97 

remediation, 3-5, 4-7, 4-9, B–28, B–61, 

B–89, B–90 

risk, xii, 3-5, 3-31, 3-36, 3-40, 5-2, 6-5, 

B–19, B–21, B–24, B–27, B–38, B–39, 

B–40, B–42, B–59, B–64, B–69, B–70, 

B–71, B–72, B–73, B–74, B–75, B–78, 

B–85, B–86, B–87, B–88, B–90, B–92, 

B–93, B–102, B–103, B–110 

scoping, 1-5, 4-2, B–7, B–21 

Shoshone, 2-4, 2-12, 2-15, 2-22, 2-23, 

2-25, 2-31, 3-25, 3-38, 3-39, 3-40, 4-20, 

6-1, 9-5, B–12, B–19, B–20, B–24, B–51, 

B–52, B–53, B–60, B–61, B–71, B–77, 

B–78, B–79, B–80, B–81, B–92, B–97, 

B–98, B–109, B–115, B–116 

solar energy, xiv, 4-7, 4-8, 6-3, B–55, 

B–104 

source term, 3-3, 3-7, 3-8, 3-21, A–2, A–3, 

A–4, A–5, A–10, A–17, B–35, B–36, 

B–58, B–63, B–70 

spent nuclear fuel (SNF), iii, xi, xiv, 1-1, 

1-5, 2-21, 3-35, 4-4, 4-5, 5-1, B–5, B–23, 

B–26, B–40, B–44, B–45, B–68, B–84, 

B–86, B–87, B–95, B–99, B–100, B–102, 

B–103, B–104, B–105, B–108, B–109, 

B–110, B–112 

State Historic Preservation Office 

(SHPO), xiv, 2-21, 3-33, 3-34, 3-35, 9-1, 

B–13, B–78, B–114 

State Line Deposits, vii, ix, 2-10, 2-11, 

2-25, 2-26, 2-27, 2-28, 2-31, 2-32, 3-2, 

3-14, 3-15, 3-16, 3-17, 3-18, 3-19, 3-20, 

3-21, 3-24, 3-30, 3-31, 3-33, 3-39, 4-15, 

4-16, 4-17, 4-19, A–14, A–18, A–19, 

B–60, B–63 

State of Nevada, xiv, 2-16, 2-17, 2-29, 4-6, 

6-1, 6-4, 6-9, 6-12, 9-6, B–20, B–21, 

B–34, B–35, B–55, B–65, B–80, B–111, 

B–116, B–119 
10-4 

Tecopa, 2-12, 2-15, 2-23, 2-25, 6-8, B–51, 

B–52, B–53, B–60, B–61, B–79, B–80, 

B–82, B–109 

Timbisha Shoshone, 2-4, 2-22, 2-31, 3-25, 

3-38, 3-39, 3-40, 4-20, 6-1, 9-5, B–12, 

B–19, B–20, B–24, B–71, B–77, B–78, 

B–79, B–80, B–81, B–98, B–109, B–115, 

B–116 

total dissolved solids (TDS), xiv, 2-23, 

3-17, 3-21, 3-24, 3-30, A–15, A–16, B–57 

Total System Performance Assessment 

(TSPA), xiv, 3-1, 3-2, 3-8, 6-12, A–1, A–2, 

A–3, A–4, A–5, A–6, A–7, A–10, A–12, 

B–3, B–21, B–30, B–31, B–32, B–34, 

B–35, B–36, B–37, B–39, B–40, B–41, 

B–42, B–45, B–46, B–47, B–70, B–74, 

B–78, B–79 

Tribe (Native American, tribal), 2-4, 2-22, 

2-31, 3-25, 3-31, 3-34, 3-36, 3-38, 3-39, 

3-40, 4-20, B–1, B–12, B–13, B–19, 

B–20, B–24, B–25, B–71, B–77, B–78, 

B–79, B–80, B–81, B–94, B–97, B–98, 

B–99, B–105, B–109, B–116, B–117 

tritium, 4-12, 4-13, 4-14, 4-16, 4-17, 4-18, 

4-19, B–90, B–96 

U.S. Geological Survey (USGS), xiv, 2-3, 

2-6, 2-7, 2-12, 2-15, 2-29, 2-30, 6-11, 

6-13, A–7, A–9, A–11, B–49, B–51, B–53, 

B–60, B–65, B–67 

volcanic, iii, xi, 1-3, 2-1, 2-5, 2-6, 2-7, 2-9, 

2-11, 2-15, 2-19, 2-27, 3-17, 4-3, 4-4, 

A–9, A–11, A–16, B–32, B–55, B–56, 

B–59, B–65, B–88, B–89 

water table, 2-6, 2-9, 2-11, 2-17, 2-18, 

2-19, 2-23, 2-25, 2-26, 2-27, 2-28, 2-29, 

2-31, 2-32, 3-7, 3-16, 3-17, 4-7, 4-9, 4-16, 

7-3, 7-4, A–12, A–14, A–15, B–49, B–50, 

B–54, B–55, B–63 

wetland, 2-20, 2-26, 2-27, 2-28, 7-2 

.
APPENDIX A 

ANALYTICAL METHODS

A–1 

APPENDIX A ANALYTICAL METHODS 

This appendix provides a description of the analysis methods used to determine impacts to 

affected environments beyond the postclosure compliance location. Section A.1 of this 

appendix describes the U.S. Nuclear Regulatory Commission (NRC) staff’s analysis framework 

for evaluating impacts over the period of geologic stability (approximately one million years). 

Section A.2 describes processes at potential discharge sites that may affect concentrations and 

exposures and how those processes are analyzed for surface discharge. 

The use of conservative assumptions simplifies calculations without underestimating impacts, 

and is warranted when the estimated impacts are small. Many of the conservative assumptions 

in the analyses for this supplement are discussed throughout the text. Section A.3 summarizes 

the important conservative assumptions used in the analyses. 

A.1 Analysis Framework

The overall analytical framework used in this supplement extends the framework used in 

previous analyses performed by the U.S. Department of Energy (DOE) in its earlier 

Environmental Impact Statements (EISs) (DOE, 2008a; 2002) and Safety Analysis Report 

(SAR) (DOE, 2008b). In this supplement, the framework is extended to analyze both 

radiological and nonradiological contaminants for one million years after closure of the 

repository, and to analyze impacts at locations beyond the postclosure compliance location 

using transport and biosphere models. 

In the 2002 EIS (DOE, 2002) and 2008 Supplemental EIS (SEIS) (DOE, 2008a), DOE 

principally used its Total System Performance Assessment (TSPA) model for assessing the 

effects of release and transport processes. This model was designed to evaluate those 

features, events, and processes of the engineered and natural barrier systems that affect 

repository performance (DOE 2008b, Chapter 2; NRC, 2015a). TSPA is a probabilistic model. 

Results are generated through multiple iterations with different values for input parameters as a 

way to account for uncertainties (the results of an iteration are termed a model realization). The 

2002 EIS and 2008 SEIS used the dose calculated in TSPA as the principal measure of 

radiological impacts on groundwater. This dose was calculated following the criteria given in 

10 CFR 63.312 for the reasonably maximally exposed individual (RMEI) residing “in the 

accessible environment above the highest concentration of radionuclides in the plume of 

contamination,” a location approximately 18 km [11 mi] south of the repository along the 

groundwater flow path (the postclosure compliance location). The RMEI exposure pathway 

includes the well withdrawal of contaminated groundwater for drinking and irrigation, as well as 

inhalation of surface dust potentially contaminated by well water. DOE provided TSPA dose 

results for the one-million-year period following permanent closure of the repository. In addition, 

in the 2002 EIS and 2008 SEIS, DOE provided TSPA results for the concentration of 

radionuclides in groundwater for the 10,000-year period following permanent closure of 

the repository. 

In the 2002 EIS and 2008 SEIS, DOE considered impacts on groundwater at other locations 

beyond the postclosure compliance location to be no greater than those calculated by TSPA for 

the RMEI location. In the 2002 EIS, DOE applied fractional scaling factors to its TSPA results at 

the postclosure compliance location to provide estimates of impacts at more distant locations. 

These scaling factors accounted for increased dispersion of a contaminant plume downstream 

along the flow path to distances of 30 and 60 km [19 and 37 mi] from the repository location 

(DOE, 2002, Section 5.4.1; Appendix I.4.5), which approximately match the distances from the 
A–2 

proposed repository to Amargosa Farms and Alkali Flat, respectively. DOE’s estimation of the 

scaling factors did not consider sorption along the flow path or other processes that could affect 

impacts. In the 2008 SEIS, DOE did not use the scaling factors, but instead stated that 

contaminant concentrations, and thus impacts, for any areas beyond the postclosure 

compliance location can be no greater than those estimated for the postclosure compliance 

location. In the Adoption Determination Report (ADR) (NRC, 2008a), the NRC staff 

concluded that this generic description of affected environments and impacts was not 

sufficient for adoption. 

A description of the source terms for radiological and nonradiological (toxic chemicals) 

contaminants is given in Section A.1.1, followed by, in Section A.1.2, a description of the 

transport models the NRC staff used for modeling the two transport segments (i) from the 

repository to the postclosure compliance location, and (ii) beyond the postclosure compliance 

location along the flow path to discharge locations, including descriptions of processes that 

occur along the different transport segments. 

A.1.1 Source Term and Mass Flux at the Postclosure Compliance Location

In the 2002 EIS and 2008 SEIS, DOE estimated the source term (the total inventory of potential 

contaminants) for radionuclides for one million years, and for toxic chemicals for 10,000 years. 

Here, the source term is the released contaminants from the repository. Mass flux for this 

analysis is the rate at which contaminants flow from the proposed repository to the postclosure 

compliance location, and then beyond the postclosure compliance location; for example, to 

Amargosa Farms or Furnace Creek in Death Valley along the groundwater flow path. 

This supplement uses TSPA results for the mass flux of radionuclides reaching the postclosure 

compliance location as an input in the transport model, which analyzes the movement of 

contaminants to different locations along the flow path. Using this mass flux for this supplement 

is conservative because the safety case evaluated for Yucca Mountain conservatively used the 

highest concentration of a plume passing the postclosure compliance location. All other points 

in the plume would have lower potential contaminant concentrations. As stated in Section 3.1, 

the NRC staff found DOE’s TSPA methodology to be acceptable as part of its safety evaluation 

(NRC, 2014a, Section 2.2.1.4.1). 

Because the source terms for radionuclides and toxic chemicals are estimated using different 

approaches, they are discussed separately in the next two subsections. This section provides a 

brief summary of the method for calculating mass flux that was used in the 2008 SEIS for the 

postclosure compliance location for radionuclides, and a description of the NRC staff’s revised 

approach used in this supplement that extends the analysis period for the mass flux of 

nonradiological contaminants at the postclosure compliance location to one million years, which 

was not part of DOE’s 2008 SEIS. The mass flux at the postclosure compliance location is a 

function of the releases from the repository and the effects of transport to the postclosure 

compliance location. The mass flux at the postclosure compliance location over the one million 

year period is used as an input to the transport model for the migration of radiological and 

nonradiological contaminants along the flow path towards Death Valley. This is described in 

Section A.1.2 (Transport to Affected Environments Beyond the Postclosure Compliance 

Location). In addition, the NRC staff revised some values in Chapter 3 to reflect peak values 

during a period (e.g., during the million-year period) instead of values at the end of the period, 

and to reflect updated entries found in staff’s consistency review of the analyses. 
A–3 

Source Term and Mass Flux at the Postclosure Compliance Location for Radionuclides

In the 2008 SEIS, DOE used mean results from the TSPA model to estimate the source term for 

radionuclides and transport to the postclosure compliance location. This supplement uses the 

same approach and results, but uses those results as inputs to the transport model that 

calculates movement of the contaminants beyond the postclosure compliance location 

(see Section A.1.2). The NRC staff found that the TSPA model and results were acceptable as 

part of its safety evaluation (NRC, 2014a; Section 2.2.1.4.1). The NRC staff also found, in its 

ADR (NRC, 2008a), that use of the TSPA results as a source term for the postclosure 

compliance location is appropriate. The amounts of radionuclides released from the repository 

over time are an intermediate result of the TSPA simulation. The simulations also include 

transport through the unsaturated and saturated zones below the repository to the postclosure 

compliance location approximately 18 km [11 mi] from the repository. The 2002 EIS also used 

this approach, but with an earlier version of the TSPA model. The analysis in this supplement 

tracks 31 radionuclides from the TSPA results as the source term for calculating radiological 

impacts in affected environments. These radionuclides were identified by DOE (2014a, Table 

B-3 and B-4) as important contributors to the calculated dose from repository releases. The 

NRC staff confirmed that these radionuclides are the important dose contributors in the NRC 

staff’s safety evaluation (NRC, 2014a, Section 2.2.1.4.1). 

DOE’s mean TSPA results were determined by averaging the behavior of the repository 

performance over the range of uncertainty and variability used to represent the features, events, 

and processes (e.g., corrosion of the waste package, seismic events, geologic and hydrologic 

characteristics of the site, or future climate conditions). TSPA uses scenario classes to 

represent specific events, such as seismic events and igneous events. DOE’s TSPA includes 

seismic activity and igneous activity as two categories of events with the potential to affect a 

large number of waste packages, and thus potentially to have a significant effect on releases. 

Seismic events are uncertain in both timing and magnitude. Therefore, TSPA considered an 

appropriate range of seismic events that could potentially occur throughout the one-million-year 

period (e.g., smaller magnitude seismic events occur much more frequently than very large 

seismic events). Thus, the TSPA results reflect the occurrence of a number of seismic events 

of different magnitudes that occur at different times throughout the million-year period, as 

reflected in the historical record for seismic events in the region and accounting for uncertainty 

associated with such events. 

The use of TSPA results to estimate releases that can be reasonably expected to enter the 

aquifer from the repository will not underestimate environmental impacts by inclusion of 

releases due to unlikely events regardless of probabilities assigned to the unlikely events. The 

TSPA model is a probabilistic tool that models uncertainty and variability in many parameters, 

including the effects of future climate change. 

In DOE’s analysis, the probability of an igneous occurrence is slightly above one chance in 

100 million. DOE’s TSPA takes into account unlikely events like igneous disruption and large 

magnitude seismic events, as well as features, events, and processes that are expected to 

occur (e.g., corrosion of the waste package, seepage of water into the repository). The NRC 

staff’s approach in using TSPA results for its evaluation in the supplement is therefore a credible 

representation of potential contaminant releases, which accounts for environmental impacts that 

are reasonably likely to occur, while including impacts from events that are much less likely 

to occur. 
A–4 

In the 2002 EIS and the 2008 SEIS, DOE used the transport submodels in the TSPA code to 

estimate radionuclide movement to the postclosure compliance location. The TSPA transport 

model incorporates the following five transport processes: 

 Advection is the migration of contaminants by the rate of groundwater flow. 

 Matrix diffusion is the exchange between the fast-flowing groundwater in fractures and 

faults with slow-flowing water in the rock matrix. 

 Sorption is the exchange of contaminants between groundwater and rock surfaces; the 

sorption coefficient describes the partitioning of the contaminant between groundwater 

and the rock (solid phase); and the magnitude of sorption is dependent on the element, 

the rock, and the groundwater chemistry. 

 Colloidal transport is the sorbing of contaminants onto colloidal particles, which can 

then be transported as undissolved species. 

 Radioactive decay and ingrowth is the decay of radioactive material over time, which 

in turn may generate new radioactive contaminants (daughter products), depending on 

the type of radioactive material. 

The transport model and outputs for radionuclides used for analyses in this supplement have 

not changed from those in the 2008 SEIS. These TSPA simulation outputs produced the mass 

fluxes of radionuclides arriving at the postclosure compliance location as a function of time for 

the one-million-year period. The NRC staff found these TSPA results acceptable as part of its 

safety evaluation (NRC, 2014a; Section 2.2.1.4.1). These results are used as the source term 

in this supplement for calculations of transport beyond the postclosure compliance location. 

The TSPA model used for the license application was derived using the draft rule (70 FR 53313) 

for the licensing of a geologic repository at Yucca Mountain. The final rule (74 FR 10811), in 

addition to other changes not relevant to this supplement, incorporated a slightly different 

distribution for deep percolation (the amount of water moving from the surface to a great enough 

depth that it is not removed by evaporation or transpiration) than the draft rule. This distribution 

represents the effect of future climates for the period from 10,000 to one million years after 

repository closure, which is applicable to the cooler/wetter climate state used in this supplement. 

The revised distribution in the final rule led to a slightly larger mean value of percolation for the 

10,000 to one million year period, which could potentially have affected TSPA results. The NRC 

staff concluded in the SER that the slight change in the mean and distribution of deep 

percolation in the final rule had no significant effect on repository performance (NRC, 2014a; 

Section 2.2.1.3.6.3.2), and therefore no significant effect on the release of radionuclides from 

the repository and transport to the postclosure compliance location, and hence, no significant 

effect on the source term used in this supplement for the postclosure compliance location. 

Source Term and Mass Flux at the Postclosure Compliance Location for 

Nonradiological Contaminants 

In its 2002 EIS and 2008 SEIS, DOE performed a screening analysis where it compared 

chemical contaminants of materials used in the construction of the repository (including waste 

package materials) with the U.S. Environmental Protection Agency (EPA) substance list from 

the Integrated Risk Information System (2002 EIS Section I-6; 2008 SEIS Section F.5). Besides 

toxicity information from the EPA substance list, a second component of DOE’s screening 
A–5 

process was the consideration of the potential for each chemical to migrate to the accessible 

environment (in DOE’s analysis, the postclosure compliance location). For nonradiological 

material, DOE only considered the first 10,000 years after closure in its screening analysis. The 

source term that DOE developed for nonradiological chemicals was based on the thickness of 

corroded material and the total surface area of repository construction and waste package 

material exposed to corrosion. Because only a few packages were predicted to fail in the first 

10,000 years after permanent closure, chemically toxic materials from within the waste 

packages were not considered. 

In the 2002 EIS and 2008 SEIS, DOE assumed the release rate due to corrosion was uniform 

over the entire 10,000-year period. In the 2002 EIS, the chemicals of concern resulting from the 

DOE screening analysis were chromium (Cr), molybdenum (Mo), nickel (Ni), and vanadium (V). 

In the 2008 SEIS, DOE screened out Cr on the basis that the expected predominant form would 

be Cr (III) (chromium in a valance state of +3) in the repository environment, which is nontoxic 

to humans and relatively insoluble; that is, significant levels would not be dissolved in water, and 

thus would not migrate into the groundwater. DOE stated that the more toxic form, Cr (VI), 

would not form by corrosion of the waste package material (Alloy 22) or stainless steel under 

repository conditions (2008 SEIS, Section F-5.1). If Cr (VI) forms from such corrosion in the 

repository, the DOE screening analysis in the 2008 SEIS found that Cr (VI) is efficiently and 

quickly reduced to Cr (III) (Eary and Rai, 1989; Palmer and Puls, 1994) in the expected 

repository environment. The NRC staff, in its safety evaluation, found the DOE description of 

the repository chemical environment to be acceptable (NRC, 2014a; Section 2.2.1.3.3). For 

nonradiological contaminants in the 2002 EIS and 2008 SEIS, DOE applied the quantity of 

nonradiological chemicals released from corrosion of construction and waste package materials 

directly to the pumping well at the postclosure compliance location, thus conservatively 

excluding any transport-related delays or reductions. 

This appendix describes the estimation of mass flux of nonradiological contaminants applied to 

the postclosure compliance location over the entire one-million-year period, beyond the 

10,000 year period evaluated by DOE. This description begins with the source term at the 

repository and adjusts for transport processes along the saturated flow path to estimate the 

one-million-year mass flux at the postclosure compliance location. The release of contaminants 

from the repository is conservatively applied directly to the unsaturated-saturated zone 

boundary below the repository. Because more waste packages are expected to fail during 

the one-million-year period, compared to the number of expected failures during the first 

10,000 years, toxic chemical contaminants from fuel assemblies and other materials inside 

waste packages are considered in addition to the materials (e.g., stainless steel or Alloy 22) 

considered in the 2008 SEIS. From the inventory of material inside failed waste packages, 

uranium (U) is the only additional contaminant added to the list of toxic chemicals because of its 

large quantity and its high toxicity (DOE, 2014a). For U, the source term is derived from TSPA 

results for radionuclides as the sum of all U isotopes arriving at the postclosure compliance 

location (as all forms of U are radioactive) (DOE, 2014a). Based on this screening process, 

which considers mobility and toxicity (DOE, 2014a), no other contaminants from inside waste 

packages are added to the list. Therefore, total U is added to Mo, Ni, and V as the toxic 

chemicals considered in this supplement. The NRC staff reviewed the mobility and toxicity 

screening process used by DOE and finds no other elements in the construction and waste 

package materials that should be included in this supplement. 

To estimate the mass flux reaching the postclosure compliance location, the source term from 

the repository is adjusted using a two-step procedure to account for delays and reductions 

during transport between the repository and the postclosure compliance location. First, a 
A–6 

simplified model is used for the release rate of nonradiological contaminants (Mo, V, Ni) from 

the repository to estimate the mass flux at the unsaturated-saturated boundary approximately 

300 m [1,000 ft] below the repository. The release rate model approach is based on the 

analysis in DOE (2014a), which used the following assumptions and values: 

 The materials that corrode to produce nonradiological contaminants include construction 

material, all waste package material, and internal fuel assemblies and spent fuel. The 

number of failed waste packages is taken from the TSPA output for the combined 

scenario case. As described earlier in this section, the combined case includes the 

nominal, early failure, igneous intrusion, and seismic ground motion-fault displacement 

scenario classes; 

 The mobilization rate for each element is calculated based on the corrosion rate used in 

the DOE’s SAR (DOE, 2008b) and the exposed area of all external material 

(from construction and waste packages) and internal material (exposed in failed waste 

packages). Note that DOE (2014a) allowed corrosion to proceed indefinitely; for this 

supplement the release ends when the thickest component has been completely 

corroded. More details on this release model are provided in the following paragraphs; 

and 

 The mobilization rate is applied at the unsaturated-saturated zone boundary, and a 

transport model based on breakthrough curves from the TSPA (DOE, 2008b) is used to 

determine the mass flux reaching the postclosure compliance location 18 km [11 mi] 

from the repository. 

The analysis in DOE (2014a) included an unrealistic assumption of the total amount of 

nonradiological contaminants that could be released from the repository. For the calculations in 

this supplement, the NRC staff constrained the total amount of the source of the nonradiological 

contaminants available in the repository, specifically the Alloy 22 (the high-nickel alloy that 

makes up the outer barrier of the waste packages) and the 316NG stainless steel (both exposed 

in the repository structures, and used in the internal components of the waste packages) such 

that the total release cannot exceed the amount in the repository. Using the corrosion rates 

from DOE’s SAR, exposed stainless steel from rock 

bolts, tunnel and drift liners, and other installed rock 

supports would be completely corroded in 

10,000 years. Internal waste package components 

would corrode over a period of 500,000 years (as 

exposed in failed waste packages), and Alloy 22 

would corrode over 600,000 years. Figure A–1 (top) 

illustrates the mass flux mobilized by corrosion and 

applied directly to the unsaturated-saturated zone 

boundary below the repository. 

The release rate calculated for each of the 

nonradiological contaminants is used to generate 

the mass flux at the unsaturated zone-saturated 

zone interface below the repository. This approach 

explicitly (and conservatively) neglects any delay or 

reduction potentially caused by transport out of the engineered barriers and through the 

unsaturated zone below the repository. 

Sorption 

Sorption is the process whereby contaminants are 

removed from the water through attachment to 

solid grains in the rock. For a continuous 

contaminant source, sorption causes a delay in the 

arrival of the peak contaminant levels at 

downstream locations, but does not reduce the 

peak contaminant level. The inclusion of 

longitudinal dispersion smooths sharp contaminant 

fronts (such as the pulse of the nonradiological 

contaminant release shown in the top of 

Figure A–1), and only affects the timing of the first 

arrival of the contaminant at downstream locations. 
A–7 

Next, the mass flux at the postclosure compliance location for nonradiological contaminants is 

calculated from the mass flux at the unsaturated zone-saturated zone boundary, modified to 

account for delays and reductions along the approximately 18-km [11-mi] flow path to the 

postclosure compliance location. Breakthrough curves from the TSPA are used to transfer the 

mass fluxes of Mo, Ni, and V from the unsaturated-saturated zone boundary below the 

repository to mass fluxes at the postclosure compliance location. Appropriate analog 

breakthrough curves were selected by matching sorption properties of the nonradiological 

contaminant with breakthrough curves derived for radiological contaminants with similar sorption 

properties. A breakthrough curve represents the arrival of a contaminant at a location as a 

function of time, and reflects the transport velocity and sorption characteristics of the 

contaminants for the various processes operating in the aquifer. The processes implemented in 

the TSPA model account for advection, matrix diffusion, dispersion, sorption, and colloidal 

processes. Together with the release rate from the repository (Section A.1.1), the breakthrough 

curve provides the mass of nonradiological contaminants at the postclosure compliance location 

as a function of time, which is used as input for the transport calculation beyond the postclosure 

compliance location described in the next subsection. The mass fluxes of nonradiological 

material at the postclosure compliance location are provided in Figure A–1 (bottom), which 

represents the nonradiological releases over the one-million-year period. 

A.1.2 Transport to Affected Environments Beyond the Postclosure Compliance Location 

In its 2002 EIS, DOE considered transport beyond the postclosure compliance location only 

through the use of fractional scaling factors for both radiological and nonradiological 

contaminants. These factors were applied to the TSPA outputs at the postclosure compliance 

location to assess impacts at more distant locations. These scaling factors nominally accounted 

for the increased dispersion of a contaminant plume migrating downstream from the 

approximately 18-km [11-mi] postclosure compliance location (DOE, 2002, Section 5.4.1 and 

Appendix I.4.5). In its 2008 SEIS, DOE stated that dose and concentration, and thus impacts, 

for areas beyond the postclosure compliance location can be no greater than those estimated 

for the postclosure compliance location. 

In this supplement, the NRC staff uses the transport analysis in the U.S. Geological Survey’s 

(USGS) Death Valley Regional Flow System (DVRFS) model (Belcher and Sweetkind, 2010). 

The DVRFS model uses the publicly available MODFLOW software (Harbaugh, 2005; 

Harbaugh et al., 2000), which is the most widely-used groundwater modeling software. The 

USGS has been developing the DVRFS model for more than 15 years (Belcher, 2004; 

Belcher and Sweetkind, 2010; D’Agnese et al., 1999). The NRC staff reviewed and accepted 

the DVRFS model as used in the SAR (DOE, 2008b; Section 2.3.9) in its safety evaluation 

(NRC, 2014a; Section 2.2.1.3.8). As used in this supplement, the DVRFS model was updated 

(SNL, 2014) by including additional years (1999–2003; in addition to original 1913–1999 data) of 

pumping data from Amargosa Farms. The DVRFS model (SNL, 2014) is used in this 

supplement to determine flow pathways and inputs for the transport model. The NRC staff 

reviewed the changes to the inputs and the resulting output, and determines that the DVRFS 

model (SNL, 2014) is acceptable for use in the analyses in this supplement. Based on the NRC 

staff’s reviews of the DVRFS models described above, the NRC staff finds the DVRFS model to 

be a reasonable representation of the flow system in the Death Valley region, including the flow 

path from Yucca Mountain to Death Valley. 

The next sections describe the transport approach used in this supplement to analyze the 

transport of radiological and nonradiological contaminants from the postclosure compliance 
A–8 

Figure A–1. Mass Flux for Mo, Ni, and V Released From Repository (Top) and Reaching 

the Postclosure Compliance Location (Bottom). To Plot All Three Metals 

on the Same Graph, a Logarithmic Mass Flux Scale Is Used. 
A–9 

location to affected environments along the groundwater flow path to Death Valley. The 

description includes the identification of the likely transport pathways and the transport model, 

including processes and properties. 

Identification of Pathways

The model the NRC staff uses for identifying the transport pathways and determining the flow 

characteristics along those pathways is based on the DVRFS model [Belcher and Sweetkind 

(2010)], modified to include data on groundwater pumping from 1913 to 2003 (SNL, 2014). 

Implemented with the MODFLOW software (Harbaugh, 2005; Harbaugh et al., 2000), USGS’s 

DVRFS model includes particle-tracking capabilities. Particle tracking is a technique commonly 

used to delineate flow pathways. Particles move through the model domain based on the flow 

direction and velocity at each cell in the model. Flow pathways are identified by releasing 

particles at the postclosure compliance location and tracking where the particles move within 

the DVRFS. Adsorption, colloidal filtering, decay, or other mechanisms that limit movement of 

the particles along with the water are neglected in this analysis for simplification and 

conservatism. In the DOE (2014a) analysis, 8,024 particles were released at the postclosure 

compliance location and tracked. The 8,024 particles used at the postclosure compliance 

location were derived from release of 10,000 particles from Yucca Mountain in the Yucca 

Mountain Site-Scale Flow Model (SNL, 2007a). When pumping is included in the DVRFS 

model, all particles are captured by the wells in Amargosa Farms. When no pumping is 

included (the pre-pumping model, representing groundwater conditions prior to 1913), particle 

tracking identifies two potential pathways downstream of Amargosa Farms. The strongly 

predominant path is approximately southward through Amargosa Farms, turning southwestward 

to westward beneath the Funeral Mountains, to the springs at Furnace Creek, and on to Middle 

Basin in Death Valley (DOE, 2014a; Figure 3-1). A potential alternative path (only two particles 

out of 8,024 leaving the postclosure compliance location took this course) is southward past 

Amargosa Farms to surface discharge at Alkali Flat (DOE, 2014a; Figure 3-2). For this 

analysis, these two particles represent the limited possibility that a small amount of 

contamination could divert from the predominant pathway. 

Particle tracking results in the DVRFS model indicate that the contaminants would travel 

through several different water-bearing segments (parts of the aquifer) along the flow path. 

Each of these segments has different transport properties. For the analysis in this supplement, 

the length of transport segments along each identified pathway are estimated from the DVRFS 

model, using separate steady state simulations with and without pumping in Amargosa Farms 

(as in DOE, 2014a). The segment lengths represent flow in different rock formations. Flow 

beyond the postclosure compliance location is primarily in volcanic-alluvial or carbonate-hosted 

aquifers. For the nonpumping scenario, two different aquifer types predominate in the flow path 

to Death Valley (DOE, 2014a): (i) the volcanic-alluvial basin fill unit comprises 46 percent of the 

path; and (ii) the lower carbonate aquifer comprises 40 percent. For the pumping scenario, the 

entire path (from the postclosure compliance location to Amargosa Farms) is comprised of 

various basin fill volcanic-alluvial units (DOE, 2014a). The NRC staff finds that the DVRFS 

segment lengths and hydrogeological units along the flow paths as described by DOE are 

acceptable and reasonable because (i) the NRC staff found the DVRFS model an acceptable 

representation of groundwater flow in the region (see above), (ii) the NRC staff reviewed the 

flow segment lengths and found them to be reasonably consistent with distances from maps of 

the hydrogeological units, and (iii) the hydrogeological units and their spatial representation are 

direct inputs from the model developed by the USGS (Belcher and Sweetkind, 2010). 
A–10 

Transport Model

The mass flux at the postclosure compliance location was estimated from the release and 

transport of contaminants from the repository, as described in Section A.1.1. This section 

describes how the contaminants at the postclosure compliance location are modeled to move 

different distances downstream using a different transport model than that used for the transport 

between the repository and the 

postclosure compliance location. 

For this supplement, transport in the 

saturated zone (i.e., the aquifer) 

downstream of the postclosure 

compliance location is modeled using the 

one-dimensional pipe model described in 

DOE (2014a). The entire contaminant 

plume is assumed to be contained in the 

pipe. As described below, a 

one-dimensional representation is 

conservative compared to a 

three-dimensional model because it neglects vertical and lateral dispersion, and thus likely 

overestimates maximum contaminant concentrations. 

Transport in the pipe is based on an analytical solution of the advection-dispersion equation 

modified for sorption and decay. The exact solution to the equation (Lapidus and Amundsen, 

1952; Equation 9) is simplified by dropping the term for short distances. The concentrationbased solution is multiplied by the volumetric flux to convert it to a mass flux-based solution. In 

addition, a mathematical identity for the complementary error function in the solution is used to 

avoid potential computational difficulties which can occur with a numerical approach. Whereas 

the analytical solution for transport is valid for a constant source term, solutions for different 

magnitudes of the source term that occur at different times are additive. Because the mass flux 

at the postclosure compliance location changes with time, the solution approach is to break up 

the source term into step changes (of radionuclide and nonradiological contaminant mass 

fluxes) and solve the transport equation for each source term step. The solution for a location 

and time is then the sum of contributions from each source term step. 

Transport processes of sorption, longitudinal (in the direction of the flow path) dispersion, and 

radioactive decay and ingrowth are incorporated in the model, but matrix diffusion and colloidal 

processes are not included. Neglecting matrix diffusion is conservative for estimating impacts 

because diffusion reduces concentrations of contaminants. DOE’s TSPA includes these 

processes, so their effects are included in the mass of radionuclides calculated to arrive at the 

postclosure compliance location. Neglecting colloidal transport beyond this point may 

under-represent the mass flux to affected environments. However, the NRC staff reviewed the 

magnitude of colloidal transport included in the TSPA and determined that this process was not 

significant to dose, and hence the mass of radionuclides that is used to estimate that dose at 

the postclosure compliance location (NRC, 2014a; Section 2.2.1.4.1). Because the same 

radionuclides and transport processes in the TSPA are analyzed in this supplement, not 

including colloidal processes will not significantly affect the estimated impacts. The processes 

of radioactive decay and ingrowth are approximated by adjusting the input source term for the 

one-dimensional pipe model to account for decay or ingrowth that would take place between 

the postclosure compliance location and the downstream location (e.g., Amargosa Farms or 

Death Valley). 

Analytical Solutions for Transport Equations 

An analytical solution to the transport equation is a 

mathematical solution in the form of mathematical 

expression. It is also called a closed-form solution. 

A numerical solution is an alternative method for 

solving the transport equation. Numerical solutions 

are needed for complex problems, but the results 

only approximate the solution to the transport 

equation. The choice of solution method generally is 

determined by the complexity of the problem, and by 

the intended usage and needs of the results. 
A–11 

The primary inputs for the transport model are sorption properties for each contaminant and flow 

path characteristics from the DVRFS model. Sorption analyses in this supplement use values 

from DOE (2014a; Table B-1). For radionuclides in volcanic and alluvial rock units, DOE 

derived the sorption values from the low end of the range provided in the SAR (DOE, 2008b; 

Table 2.3.9-14), and updated them based on more recent literature (DOE, 2014a). Larger 

values of sorption coefficients lead to delayed arrivals of contaminants at downstream locations, 

such as delays in the time of peak concentrations. The NRC staff found that the values in 

DOE’s SAR were acceptable as part of its safety evaluation (NRC, 2014a, Section 2.2.1.3.10). 

Further, sensitivity analyses using a set of significantly lower sorption values for all 

contaminants (except non-sorbing species where the sorption coefficient is zero) (DOE, 2014a, 

Table B-16; DOE, 2008b, Table 2.3.9-14) showed only a 15 percent increase in dose and body 

uptake impacts (DOE, 2014a). This small increase in impacts would not change the 

conclusions in Chapter 3 of this supplement. Therefore, the NRC staff finds the sorption 

properties in DOE (2014a, Tables B-1) reasonable for use in this supplement for the 

transport model. 

Secular equilibrium for decay chain isotopes is a valid assumption when the sorption 

coefficients of parent and daughter products of radionuclides are similar in magnitude. In its 

2002 EIS and 2008 SEIS, DOE assumed secular equilibrium for all radionuclides in decay 

chains. In DOE (2014a), DOE screened radionuclide decay chains for parent and daughter 

radionuclides with large differences in respective sorption coefficients. DOE identified the 

actinium, neptunium, thorium, and uranium series in the screening analysis (DOE, 2014a). The 

NRC staff reviewed the screening of radionuclide series for secular disequilibrium in the SAR, 

and found this same list acceptable for use in the SAR (NRC, 2014a; Section 2.2.1.3.9). In this 

supplement, the effect of secular disequilibrium is accounted for by applying a scaling factor to 

the dose conversion factors for radionuclides of parent-daughter pairs with different sorption 

characteristics. Any factor above one has the effect of increasing the estimated dose impact of 

the identified radionuclide species. Following the approach described in Olszewska-Wasiolek 

and Arnold (2011), the factors used in this supplement are 8.7 for Ra-228 and 1.8 for lead-210 

(Pb-210) and Ra-226 (shown in DOE, 2014a, Tables B-3 and B-4). 

For the flow path characteristics, DOE derived the following from the DVRFS model: (i) bulk 

density, porosity, and flow path length in each rock unit (referred to as flow segments), and 

(ii) specific discharge. The values for each flow path are provided in DOE (2014a, Table B-1), 

and their derivation is summarized below. The NRC staff finds the DVRFS 

hydrogeological properties of each flow segment along the flow paths acceptable and 

reasonable because (i) the NRC staff found the DVRFS model of Belcher and Sweetkind (2010) 

an acceptable representation of groundwater flow in the region in its safety evaluation 

(NRC 2014a; Section 2.2.1.3.8), (ii) the NRC staff reviewed the flow segment lengths in 

DOE (2014a) and found them to be reasonably consistent with distances from maps of the 

hydrogeological units (e.g., Belcher and Sweetkind, 2010), and (iii) the hydrogeological units 

and their spatial representation are direct inputs from the model developed by the USGS 

(Belcher and Sweetkind, 2010). 

These parameters are derived as follows. Particle track modeling indicates the different 

hydrogeological units that water flows through along the paths from the postclosure compliance 

location to either Amargosa Farms or to Furnace Creek/Middle Basin. The distance the particle 

travels in each hydrogeological unit is the length of the flow segment, which, when summed, 

provides the total flow path length. For bulk density and porosity, a single value for the entire 

flow path length is derived using a distance-weighted average of the properties for the individual 

segments along the pathway. Specific discharge is calculated as the average travel time of 
A–12 

particles divided by the total length of the flow path. For the cooler/wetter climate state, the 

specific discharge rate is increased by a factor of 3.9 over that of the present-day climate to 

account for potentially faster groundwater flow under the wetter conditions. Whereas a 

cooler/wetter climate would lead to both a higher water table and faster flow rates, the NRC staff 

review in the SER (NRC, 2014a; Section 2.2.1.3.8) concluded that only the faster flow rates 

need be considered for the transport model. The factor of 3.9 was derived from simulations of 

wetter conditions using the DVRFS model (D’Agnese et al., 1999; SNL, 2008a, Table 6-5), 

and was used for the glacial-transition climate in TSPA model simulations (DOE, 2008b, 

Section 2.4). The NRC staff reviewed the basis for the factor of 3.9 and found it to be an 

acceptable representation of the glacial-transition climate and for the long-term climate change 

during the 10,000 to one million-year period in its safety evaluation (NRC, 2014a, 2.2.1.3.8). 

A separate calculation is required to estimate contaminant concentrations in the 

aquifer environment between the postclosure compliance location and Amargosa Farms 

(see Section 3.1.1) because the one-dimensional pipe-model approximation does not account 

for the potential plume dimensions. The contaminant concentration for the aquifer environment 

is estimated as the difference between the amount of radiological or nonradiological mass at the 

postclosure compliance location and that at the Amargosa Farms divided by the volume of the 

aquifer environment. The volume of the aquifer environment is conservatively estimated by the 

dimensions of the particle tracking traces in DOE (2014a, Figure 3-1; 2008b, Figure 2.3.9-14). 

This volume estimate is conservative because particle tracking neglects lateral and vertical 

dispersion, which would lead to larger aquifer volumes and lower concentrations. From these 

values, representative dimensions of the plume are 3 km [1.9 mi] wide and 100 m [330 ft] thick. 

The third dimension of the volume is the distance between the postclosure compliance location 

and Amargosa Farms, which is 17 km [11 mi]. The next section provides a description of 

processes at surface discharge locations, for which the mass fluxes are used as input to 

estimate impacts at those locations. 

A.2 Processes at Discharge Sites 

For groundwater withdrawal for irrigation, a conceptual model for the recycling of irrigation water 

pumped to the surface was not included in DOE’s 2002 EIS or 2008 SEIS. The irrigation 

recycling model used in this supplement is described in Section A.2.1. Processes that can 

affect accumulation, concentration, and potential remobilization of groundwater-borne 

contaminants, including the influence of different chemical conditions at natural discharge sites 

such as springs or evapotranspiration at wet playas, are discussed in Section A.2.2. 

A.2.1 Groundwater Pumping, Recycling, and Irrigation 

Groundwater may be discharged at the surface due to pumping or through natural discharge 

features, such as springs, seeps, and wet playas. In the Amargosa Farms region, a significant 

amount of shallow alluvial aquifer groundwater is pumped and used as a source of domestic 

and commercial water supply and for the irrigation of crops. As irrigation water is applied to 

soils, its chemical constituents can be taken up by crops, sorbed to soils, and concentrated by 

the effects of evaporation and transpiration. These processes can lead to the buildup of salts 

and other elements detrimental to continued farming and the broader ecosystem. In addition, in 

the Amargosa Farms region, excess irrigation water is applied to compensate for evaporation 

and to limit the buildup of salts in the root zone of the soil (DOE, 2014a). Excess irrigation is the 

practice of applying more irrigation water than is needed by the particular crop, thus enabling 

the excess water to recharge the water table while carrying the salts (and in this modeling case, 
A–13 

some of the contaminants) away from the upper soil layers. The water that reinfiltrates the 

aquifer then becomes available again for groundwater pumping. 

This practice adds a complicating factor in assessing impacts from irrigation where irrigation 

water percolates deep into the subsurface and is recaptured and recycled at pumping locations. 

Where this occurs, the recycling process increases concentrations of contaminants in the 

groundwater and thus increases the concentrations of contaminants as they are reapplied to 

the surface during irrigation. Groundwater pumping at Amargosa Farms is on the order of 

17,000 acre-ft/yr [21 million m3

/yr]. This high volume of irrigation indicates that use of an 

irrigation recycling model is warranted for the assessment of impacts at Amargosa Farms. 

For this supplement, a mathematical analytical solution describing an equilibrium concentration 

is used to incorporate the impacts of irrigation recycling at the Amargosa Farms area, following 

the approach in DOE (2014a; SNL, 2007b). This mathematical solution, referred to hereafter as 

the special-case model, neglects the effects of radioactive decay. Neglecting decay 

overestimates radionuclide concentrations and, therefore, impacts. DOE (2014a) notes that 

more detailed irrigation recycling models have been developed (SNL, 2007b; Kalinina and 

Arnold, 2013), but that the special-case model represents a limiting case of the more detailed 

irrigation recycling models. The NRC staff finds that the irrigation recycling model in 

DOE (2014a) represents a reasonable, limiting case that would lead to conservative results for 

this analysis. 

The output of the irrigation recycling model that is used in this supplement is used to increase 

the amount of recycled groundwater. The irrigation recycling model includes two factors to 

calculate the change in concentration of dissolved contaminants in groundwater resulting from 

irrigation recycling: (i) the amount of pumped water used for irrigation and (ii) the amount of 

irrigation water recaptured by pumping wells (DOE, 2014a). For the first factor, 86 percent of 

pumped groundwater on average in the Amargosa Farms area is used for irrigation (Moreo and 

Justet, 2008). For the second factor, this supplement conservatively assumes that 100 percent 

of the irrigation water is subsequently recaptured by the Amargosa Farms area wells, and also 

assumes no decay of the contaminants. In addition, this model also assumes that none of the 

contaminants in the plume are sorbed to the aquifer during deep percolation. As a result of 

these factors and assumptions, the model used in this supplement produces an increase in 

groundwater contaminant concentrations by a factor of 7.1, which is much larger than values 

(1.1 to 1.5) used to assess the impacts of irrigation recycling at the postclosure compliance 

location in the SAR (DOE, 2014a; Kalinina and Arnold, 2013; SNL, 2007b). The calculated 

changes in groundwater concentrations are then applied to the contaminant concentrations in 

the transport model for the Amargosa Farms area to incorporate the impact of irrigation 

recycling in the groundwater pumping scenario. The NRC staff finds the DOE implementation of 

the irrigation recycling model in DOE (2014a) acceptable and reasonable for use in this 

supplement because (i) the NRC staff reviewed the irrigation model in the SER and found it 

acceptable as part of its safety evaluation (NRC, 2014a; Section 2.2.1.2.1, FEP 1.4.07.03.0A); 

and (ii) the irrigation recycling model input for recapture was changed to a maximum possible 

value, and the percentage of pumped groundwater in Amargosa Farms was set to the actual 

value determined by Moreo and Justet (2008); and (iii) radioactive decay is conservatively 

neglected for the recaptured water. 

Two forms of the irrigation recycling model used in this supplement are applied at two locations: 

Amargosa Farms and the State Line/Franklin Well area. Recycling is included for Amargosa 

Farms where wells that pump water for irrigation are generally located in the farm fields where 

the irrigation water is applied. Recycling is not included in the salt marsh model used for the 
A–14 

State Line/Franklin Well area because the water from springs and marshes would not be 

applied at the location it is discharged. In any potential irrigation at the State Line/Franklin Well 

area, fresh water from springs and marshes would be diverted to locations downstream from the 

extraction location where soils are not highly saline. In this type of environment, areas close to 

springs and marsh areas would contain high levels of salts, and thus would be unsuitable 

for agriculture. 

A.2.2 Processes at Surface Discharge Locations that Could Affect Accumulation, 

Concentration, and Potential Remobilization of Contaminants 

In the 2002 EIS and 2008 SEIS, DOE did not include an assessment of impacts from 

groundwater-borne contaminants downstream of the postclosure compliance location. 

Although potential groundwater flow paths downstream of the compliance location were 

discussed in the 2008 SEIS, there was limited description of groundwater-surface interaction 

processes and no quantitative assessment of impacts from groundwater discharging at the 

ground surface beyond the postclosure compliance location. 

As discussed in Chapter 2, natural groundwater surface discharge features in the 

Yucca Mountain region include springs, seeps, evapotranspiration zones with near-surface 

water table levels, and wet and dry playas. For the analysis in this supplement, these are 

grouped into springs and wet playas, or are neglected because exposure pathways for 

evapotranspiration are much smaller than for springs or wet playas. Besides present-day 

features, there are also paleospring deposits (e.g., the State Line Deposits) along the 

groundwater pathway from Yucca Mountain that show surface discharge during past wetter 

climate periods (Section 2.3). The specific processes that occur at these different types of 

groundwater discharges are dependent on several factors, including the host rock lithology, the 

groundwater chemistry, the topographic setting, the rate of evaporation, and the ecology of the 

sites (e.g., Douglas, 2004; Hardie, 1968; Quade et al., 1995; Reynolds et al., 2007). 

Springs and paleosprings in the Yucca Mountain region are often associated with brownish, 

fine-grained, silt-sand sediment deposits; variable carbonate cementing of sediments; and 

greenish clay deposits (Quade et al., 1995). Quade et al. (1995) classified the springs into two 

main types: 

 Springs where the water table intersects with the ground surface (free-face discharge, 

exemplified by the State Line Deposits) 

 Springs controlled by faulting or other geologic features (structure-controlled discharge, 

exemplified by springs at Furnace Creek) 

In areas adjacent to both spring types, an ecological hierarchy is commonly developed in which 

plants transition from sparse xerophytes (plants adapted to very arid environments) upgradient 

of the spring, to large phreatophytes (deep-rooted plants that obtain water from the water table) 

near the spring, to grassy wet meadows downstream from the spring (Quade et al., 1995). 

These ecological zones trap different types of sediment and produce the brownish silts, green 

clays, and calcite-cemented crusts near the zone edges (Quade et al., 1995). When the water 

table is lowered, as in the present-day climate, erosion and channeling of the sediments 

deposited in the paleospring can occur, and the phreatophytes are replaced by xerophytes 

(Quade et al., 1995). This process can be observed in the Furnace Creek spring area. 

Because the regions near these springs would have limited agricultural activity, the analyses in 

this supplement do not include irrigation recycling for these areas. However, the analyses do 
A–15 

include potential exposure from use of the springs as a drinking water source, as well as 

impacts from exposure to sediments contaminated by groundwater. 

As groundwater moves closer to the surface or is discharged at the surface, it is impacted by 

gas exchange with the atmosphere, sorption on minerals in the soil, and concentration effects. 

Groundwater in the subsurface typically has an elevated concentration of carbon dioxide (CO2), 

relative to surface water in equilibrium with the atmosphere, due to chemical exchange with 

carbonate rocks in the aquifer. As the groundwater is discharged, it re-equilibrates with the 

atmosphere. Depending on the overall chemical composition of the groundwater, the loss of 

CO2 may result in the precipitation of carbonate minerals, such as calcite. In the Yucca 

Mountain region, precipitation of calcite is observed at springs that originate from the carbonate 

aquifer, like those in Ash Meadows or Furnace Creek (Johannesson et al., 1997; Paces et al., 

1997). Other effects from the loss of CO2 may include an increase in pH (alkalinity) of the 

groundwater. Both pH and CO2 concentration changes can affect the potential for sorption onto 

soil and other surface sediments. The modeling described in this supplement uses the sorption 

values reported in DOE (2014a) to calculate the retention of contaminants on soils and 

sediments. The mean values reflect a range of sorption values that capture the range of pH and 

CO2 effects on sorption. 

At wet playas, the upward movement of groundwater is not driven by water table interactions, 

but by capillary action that draws the groundwater upward. Nearer the surface, the groundwater 

is subject to evaporation and evapotranspiration. These processes tend to concentrate the 

chemical constituents in the groundwater and increase the total dissolved solids (TDS) content 

of the water. As more water is lost, the water becomes more saline, and solubility limits for 

minerals may be exceeded. Various carbonates, salts, and other evaporite minerals may 

precipitate. This action produces a soft surface of evaporite phases that are typically rich in 

minerals such as calcium carbonate, hydrated calcium sulfate, sodium chloride, and sodium 

sulfate (DOE, 2014a). The specific types of evaporite minerals that form are dependent on the 

initial groundwater chemistry and the extent of evaporation, and the deposits are often zoned 

(Hardie, 1968). The evaporite deposits are found both in the capillary fringe area and on the 

surface of a playa (DOE, 2014a); extreme evaporation in a closed basin can lead to thick, 

zoned sequences of relatively pure evaporite minerals, as in Badwater Basin in Death Valley 

(e.g., Hunt and Mabey, 1966). As the evaporite mineral crystals form, they also displace and 

mix with the rock-derived sediments (often fine silts and clays), expanding the sediments 

upward (DOE, 2014a; Reynolds et al., 2007). The playa deposits with evaporite minerals are 

often described as “fluffy” with large pore space and low density (Reynolds et al., 2007). At the 

surface, microbial activity may produce mats that trap additional sediment and control the types 

of mineral phases that form (Douglas, 2004). Sometimes a more compact, but still friable 

(easily crumbled) material forms, which contains a lower fraction of evaporate minerals 

(DOE, 2014a). These types of deposits are associated with lower rates of evaporation or lower 

salinity in the groundwater (DOE, 2014a). The residual water is highly mineralized. For 

example, at Alkali Flat (Franklin Lake Playa), stagnant water has TDS content of 70,000 to 

80,000 ppm, and drainage paths have water with TDS content of 6,000 to 20,000 ppm (DOE, 

2014a; Reynolds et al. 2007). For comparison, a maximum contaminant level of 500 ppm TDS 

is recommended for drinking water under the National Secondary Drinking Water Regulations 

(40 CFR 143.3). 

The effect of evaporation and evaporite mineral formation on the contaminants is to concentrate 

them in the groundwater and eventually incorporate them into the evaporite mineral phases. 

The dose model in this supplement does not include assumptions about preferential retention or 

partitioning of contaminants into specific precipitated minerals. Although some preferential 
A–16 

partitioning is likely, this is a reasonable assumption that ensures all contaminants are available 

for subsequent dose assessments due to exposure to evaporite particulates from soil 

disturbances. If preferential partitioning occurred, contaminants would only be available for 

exposure pathways for some fraction of time. At other times, burial and precipitation of 

uncontaminated evaporates would lead to lesser or no impacts. 

In this supplement, contaminant concentrations are estimated in the surficial materials at wet 

playas by using the ratio of the contaminant concentration to the observed TDS in the 

groundwater. This approach for estimating contaminant concentrations in surficial materials is 

conservative for several reasons. First, this approach conservatively assumes that evaporites 

are the only component of the surficial material; including the rock-derived component (e.g., silt, 

clay) of the surficial material would dilute the contaminant concentration. Second, the TDS in 

the groundwater is conservatively assumed to be 257 ppm, which is the TDS from the J-13 well. 

The J-13 well measured the volcanic aquifer below Fortymile Wash and upstream of the 

postclosure compliance location. Because TDS generally increases with the time or distance 

that water is below ground, the TDS from J-13 is lower than that in groundwater downstream of 

the postclosure compliance location. For comparison, the measured TDS of spring water at 

Furnace Creek is approximately 600 ppm TDS (Steinkampf and Werrell, 1998); using this value 

for TDS would decrease the contaminant concentration in evaporite to less than half that of the 

estimate provided in Chapter 3 of this supplement. Third, this approach for estimating evaporite 

concentrations is conservative because the evaporites, which include potential contaminants, 

can be redistributed by wind and rainfall. Since many of the evaporite minerals are highly 

soluble, they can be dissolved and redistributed during periods of water inundation and flow. 

Redistribution of the contaminated evaporite particulates would tend to disperse contaminants 

over a larger area and dilute their concentration. 

A.2.3 Biosphere Exposure and Dose Conversion 

This section provides a discussion of the biosphere model, which includes exposure pathways 

and the conversion of contaminant levels to a dose (for radionuclides) or a body uptake 

(for nonradiological contaminants) for each of those pathways. 

For radiological and nonradiological contaminants that reach the biosphere (or accessible 

environment), either through groundwater pumping or natural surface discharge, the impacts to 

that environment are assessed by first determining the exposure pathways. The contaminant 

level (i.e., concentration) is then converted to an impact using a dose conversion factor for 

radionuclides or a body uptake factor for toxic chemicals. The dose conversion and body 

uptake factors depend on the exposure pathways in each environment. For radionuclides, the 

resulting annual dose to humans is compared against natural background levels and the 

criteria specified for safety in 40 CFR Part 197 and 10 CFR Part 63 for the RMEI. For 

nonradiological contaminants, body uptake is compared directly against an Oral Reference 

Dose (e.g., EPA, 1999a,b; 1997a,b; 1994). 

In its 2002 EIS and 2008 SEIS, DOE assessed impacts using a conceptual biosphere model 

with a broad range of water uses and exposure pathways, as shown in Figure A–2. In this 

supplement, three environments with different exposure pathways are developed. These three 

environments are 

 Environment 1: Irrigation Pumping and an Agricultural Community 

 Environment 2: Surface Discharge as Springs with a Local Non-Farming Community 

 Environment 3: Surface Discharge at Wet Playas 
A–17 

Figure A–2. Water Uses and Exposure Pathways in the Biosphere Conceptual Model. 

See Text for Discussion of Relevant Pathways for Each Environment. 

(Source: SNL, 2007c, Figure 6.3-3). 

The biosphere exposure framework in Figure A–2 lists a range of potential pathways, but not all 

water uses and exposure pathways apply to each environment in this supplement. For the 

pathways for each environment, dose conversion factors were derived from SNL (2007c) for the 

31 radionuclides that make up the source term from the repository (DOE, 2014a). The NRC 

staff, as part of its safety evaluation, found the biosphere exposure framework and dose 

conversion factors to be acceptable (NRC, 2014a; Section 2.2.1.3.14). The impacts from total U 

and the nonradiological contaminants Mo, Ni, and V are assessed by estimating the daily 

uptake amount. 

Environment 1: Irrigation Pumping and an Agricultural Community

This environment includes groundwater pumping for irrigation and groundwater use for a 

domestic and commercial water supply in an agricultural community. Presently, 

Amargosa Farms is the only location along the flow path from Yucca Mountain where extensive 

groundwater pumping occurs. The population eats locally grown food, both plants grown in 

fields and animals raised in the area, and works and lives in areas where the soils could 

become contaminated by water pumped for irrigation. Some fraction of the contaminants can 

leach back into the aquifer and possibly be recaptured by pumping wells, and some fraction 

would escape by soil erosion. In addition, decay and ingrowth will affect radionuclide 

concentrations. These processes are captured in the irrigation recycling model described in 
A–18 

Section A.2.1. The recycling processes affect the source radionuclide concentration in well 

water, which is the input in Figure A-2. 

The dose pathways for this environment (e.g., Amargosa Farms) are (i) external (body) 

exposure to contaminated soil, dust or water; (ii) inhalation of contaminated soil particles 

(including Ra-226) and vapor from evaporative coolers; and (iii) ingestion of water, crops, meat, 

fish, and soil. These pathways have not changed from those used in the 2002 EIS and 2008 

SEIS. The dose conversion factors used in this supplement are from DOE (2014a, Table B-3), 

which were derived from the maximum values in the distributions provided in the SAR 

(DOE, 2008a; Table 2.3.10-12). The NRC staff found the dose conversion factors in the SAR 

acceptable in its safety evaluation (NRC, 2014a; Section 2.2.1.3.14). The dose conversion 

factors have been adjusted for secular disequilibrium for identified radionuclides as described in 

Section A.2.2. 

The intake of toxic chemicals from the repository (Mo, Ni, V, and total U) at an agricultural 

community is based on daily intakes by a 70-kilogram [150-lb] person drinking 2 liters [8.5 cups] 

of water per day. The daily intake is equal to the water concentration times the daily amount 

consumed, divided by the weight of a person. 

Environment 2: Surface Discharge at Springs with a Local Non-Farming Community

For Environment 2, groundwater is discharged in springs and lost by evapotranspiration. The 

spring water may be used for a local water supply. The areas surrounding springs are sites for 

evaporation and transpiration that could lead to evaporite minerals forming in contaminated 

soils, and potentially plants with contaminated uptake. Examples of spring environments along 

the groundwater flow path are Furnace Creek springs under the present-day and wetter climate 

states, or the State Line Deposits/Franklin Well area under a wetter climate state. 

The biosphere model for a spring environment includes exposure pathways of (i) inhalation of 

contaminants in dust resuspended into the air and vapor from evaporative coolers, (ii) ingestion 

of water for drinking and inadvertent ingestion of soil, and (iii) external exposure from 

contaminant deposits at or near the ground surface. The model does not include groundwater 

pumping or ingestion of contaminated foods. The dose conversion factors used in this 

supplement are from DOE (2014a, Table B-4), which were derived from the maximum values 

in the distributions provided in the SAR (DOE, 2008a; Tables 2.3.10-11 and 2.3.10-12). The 

NRC staff found the dose conversion factors in the SAR acceptable in its safety evaluation 

(NRC, 2014a; Section 2.2.1.3.14). The dose conversion factors have been adjusted for secular 

disequilibrium for identified radionuclides, as described in Section A.2.2. 

Intake of chemical contaminants at a springs-type environment is based on daily intakes by a 

70-kilogram [150-lb] person drinking 2 liters [8.5 cups] of water per day. The daily intake is 

equal to the water concentration times the daily amount consumed, divided by the weight of 

a person. 

Environment 3: Surface Discharge at Wet Playas

At playas, groundwater comes close to the ground surface and evaporates or transpires, leaving 

evaporite minerals in the surficial materials (soil and evaporite). The evaporite mineral content 

and percentage in the surficial materials can be highly variable. The nonevaporite material is 

comprised of soil present prior to playa formation, the windblown dust deposited concurrently 

with evaporite precipitation, and other sediment carried in from higher elevations by sporadic 
A–19 

flooding. Water in the surficial materials and at the surface can be highly variable in 

composition, but is often saline. Intermittent or local springs may also occur, but the amount of 

potable water is generally insufficient to support a local human population. The environment 

is not conducive to farming, and natural vegetation is typically sparse and composed of 

salt-tolerant species. Examples of playas without prominent springs are the Middle Basin of 

Death Valley and Alkali Flat. For future wetter climates, the State Line Deposits area would 

likely also have wet playas, but may also have springs, pools, and marshes. 

The exposure pathway for playas includes (i) inhalation of resuspended contaminated dust, 

(ii) ingestion of contaminated water and inadvertent ingestion of evaporites, and (iii) external 

(body) exposure to contaminated water or evaporites. A full-time resident living at the discharge 

areas with the exposure pathways is conservatively assumed. To account for periodic airborne 

resuspension of surface contaminants without significant soil disruption (i.e., no heavy 

machinery causing dust resuspension), a value of 0.1 mg/m3

 [6 × 10−9 lb/ft3] is used for the 

annual average airborne particle concentration. This represents a maximum long-term value for 

airborne particle concentrations in the affected environment. The value for resuspension is 

taken from the distribution provided in DOE (2008b; Table 2.3.10-10). The NRC staff finds this 

an acceptable and reasonable value, because the NRC staff found the distribution to be 

acceptable as part of its safety evaluation (NRC, 2014a; Section 2.2.3.1.14). The airborne 

particle concentration is used with a long-term average breathing rate and an assumed 

inhalation intake duration for the entire year. These assumptions conservatively overestimate 

both annual intakes of inhaled contaminants and annual doses. Dose conversion factors used 

for Environment 3 were derived from SNL (2007c, Tables 6.4-4 to 6.4-6), which the NRC staff 

found acceptable as part of its safety evaluation (NRC, 2014a; Section 2.2.1.3.14). 

Intake of chemical contaminants is for a receptor who is active on the playa but not operating 

heavy machinery that would create dust. It is based on daily intakes by a 70-kilogram [150-lb] 

person inadvertently ingesting or breathing dust from contaminated evaporites. The amount 

inhaled is estimated from the concentration of suspended particles. The daily intake is equal to 

the evaporite concentration times the daily amount ingested and inhaled, and divided by the 

weight of a person. 

Climate States

Biosphere dose conversion factors would differ for different climate states because groundwater 

use and resulting exposures vary with climate. For example, a cooler/wetter climate requires 

less irrigation and thus results in a lower concentration of radionuclides in fields due to the use 

of less (potentially contaminated) groundwater for irrigation. The present-day climate, which is 

characterized as the driest of the anticipated climate states, would have the highest biosphere 

dose conversion factors. For the calculations of impact in this supplement, biosphere dose 

conversion factors for the present-day climate were used for all of the climate scenarios for 

conservatism. 

A.3 Conservative Assumptions Used in the Model Calculations 

Many conservative assumptions were used in the calculations of impacts in Chapter 3. 

Because of these conservatisms, the NRC staff expects that the actual impacts would be 

smaller than those calculated in this supplement. The most notable conservatisms in the 

analyses in this supplement include: 
A–20 

 At each natural surface discharge location, it was assumed that the entire contaminant 

plume was discharged therein. This likely overestimates the impacts at any one location 

because contaminants from the repository would likely discharge at several discharge 

locations. For example, for the present-day climate with no pumping (Analysis Case 2), 

it is much more likely that some fraction of the plume would discharge at Furnace Creek 

springs, and that a larger fraction would continue to Middle Basin. Or, if pumping in 

Amargosa Farms is at some significantly lower rate than is used in Analysis Case 1, 

some portion of the contaminants could bypass Amargosa Farms irrigation wells and 

discharge instead at Furnace Creek and Middle Basin. 

 The dose conversion factors for the Amargosa Farms area are derived for the 

characteristics of the RMEI (a hypothetical individual) in a manner that results in 

maximum annual and lifetime doses, which would not necessarily be representative of 

the population. The dose to the population in Amargosa Farms would be less than that 

to the maximally exposed hypothetical individual. 

 The dose conversion factors are derived for the present-day climate and would be less 

for a future wetter climate. The dose conversion factors for the present-day climate were 

applied to both climates in the analyses for Section A.2.3, and thus likely overestimate 

dose for the future wetter climate. 

 Natural surface discharge rates are likely underestimated for future climate conditions, 

which would affect estimates used for the no pumping scenario in Analysis Case 2. 

Model estimates of discharge flow rates are supported by indirect measurements, and 

were used at Middle Basin (evapotranspiration), Furnace Creek (spring flow), and Alkali 

Flat (evapotranspiration). However, current regional pumping likely lowers the natural 

surface discharge rates compared to what might be expected without pumping. Use of a 

lower surface discharge flow rate would overestimate the concentration of contaminants 

using the biosphere model described in Section A.2.3, and thus potentially 

overestimate impacts. 

 Lateral and vertical dispersion are not considered along the flow path beyond the 

postclosure compliance location. Dispersion spreads out the plume and reduces the 

peak concentration wherever it would occur. Mixing of the contaminated plume with 

water from other aquifers along the path increases dispersion, such that the 

concentrations in the plume would decrease at each location where mixing occurs. 

Mixing of water from beneath Yucca Mountain with other components occurs at the 

(i) confluence of groundwater from east of Fortymile Wash into Amargosa Desert near 

Amargosa Farms (east of Fortymile Wash and west of Ash Meadows); (ii) confluence of 

Fortymile Wash with eastward-flowing groundwater in Amargosa Desert; and 

(iii) confluence with the carbonate aquifer south of Amargosa Farms, either under the 

Funeral Mountains or with groundwater from Ash Meadows in Carson Slough and 

Alkali Flat. 

 The irrigation recycling model (see Section A.2.1) neglected radioactive decay and 

sorption of contaminants. This provides a conservative result because it does not 

include reductions in contaminant concentrations in the soil column during percolation 

back into the aquifer. 

 The NRC staff’s evaluation assumes that doses and intakes would be proportional 

to evaporite concentrations at playas. This is a conservative assumption because 
A–21 

(i) low-end estimates of dissolved solids in the water were used to estimate radiological 

and nonradiological concentrations in the precipitated evaporites, (ii) zonation of 

evaporation sequences and burial may reduce availability of contaminants for dust 

resuspension, and (iii) rock-based clastic soils and windblown dust would make up 

some of the surficial material, and therefore reduce the effective concentration 

of contaminants. 

The magnitude of the effect of these conservative assumptions is not quantified in this model. 

Each of these assumptions serves to potentially overestimate the calculated potential impacts of 

contaminants on groundwater and the aquifer, and surface discharge sites to capture 

uncertainty and the range of potential impacts.

APPENDIX B 

RESPONSES TO PUBLIC COMMENTS

B–1 

APPENDIX B RESPONSES TO PUBLIC COMMENTS 

This appendix contains comment summaries and responses. 

B.1 Public Comment Process for the Draft Supplement 

The U.S. Nuclear Regulatory Commission (NRC) staff published NUREG–2184, the draft 

“Supplement to the Department of Energy’s Environmental Impact Statement for a Geologic 

Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at 

Yucca Mountain, Nye County, Nevada” (supplement) in August, 2015. The NRC staff also 

distributed the draft supplement to persons and organizations on the adjudicatory distribution list 

in the Yucca Mountain licensing proceeding, Federal and State government agencies and 

organizations, Native American tribes, and other interested stakeholders. The public comment 

period on the draft supplement began on August 21, 2015, and ended on November 20, 2015. 

As part of the process to solicit public comments on the draft supplement, the NRC staff took 

the following actions: 

 placed the draft supplement Federal Register Notice on the NRC’s Web site and on the 

Federal rulemaking Web site (www.regulations.gov) under Docket NRC2–015–0051 

 advised stakeholders and published a press release on August 13, 2015, that the draft 

supplement was available for review and provided a link to the supplement on the 

NRC’s Web site 

 published a request for comment on the draft supplement in the Federal Register on 

August 21, 2015 (80 FR 50875) 

 sent electronic or paper copies of the draft supplement to participants in the NRC’s 

adjudication for the repository, members of the public, environmental interest groups and 

nongovernmental organizations, representatives of tribes, and Federal, State, and local 

government agencies 

 announced and held a public meeting via teleconference on August 26, 2015, to explain 

the public comment process and respond to questions from stakeholders 

 announced (via press releases, e-mails, and Federal Register notices) and held public 

meetings in Rockville, Maryland (three meetings, two of which were teleconference-only 

meetings); Las Vegas, Nevada; and Amargosa Valley, Nevada 

 published on September 18, 2015, a Federal Register Notice of extension to the 

comment period from 60 to 91 days, which extended the comment period to 

November 20, 2015, (80 FR 56501) 

 issued press releases announcing issuance of the draft supplement, the beginning of the 

comment period, the public meetings, and extension of the public comment period 

 used the NRC’s Web site at http://www.nrc.gov/waste/hlw-disposal/key-documents.html 

to aid public review of the draft supplement by posting the draft supplement and related 

announcements in the Federal Register and in press releases, meeting times and dates, 
B–2 

meeting materials (e.g., slides, transcripts, summaries, and webcast archives), and 

meeting handouts and posters 

B.1.1 Public Meetings

During the 91-day public comment period, the NRC staff conducted five public meetings. The 

public meeting in Rockville, Maryland, on September 3, 2015, featured a live webcast and 

moderated teleconference line to accommodate remote participants. The meetings on 

October 15 and November 12, 2015, were teleconference-only meetings to ensure that 

stakeholders unable to participate in the previous public meetings were afforded another 

opportunity to present oral comments. In addition, the NRC staff held public meetings in 

Las Vegas, Nevada, and Amargosa Valley, Nevada. Approximately 265 people attended or 

participated in the public meetings. A certified court reporter recorded oral comments and 

prepared written transcripts of all five meetings, and the NRC staff prepared meeting summaries 

with a list of participants for each meeting. Meeting summaries and transcripts can be found in 

ADAMS under the accession numbers listed in Table B-1. 

Notices for public meetings were included in Federal Register notices (80 FR 50875 and 

80 FR 56501), on the NRC’s Web site at http://www.nrc.gov/waste/hlw-disposal/keydocuments.html and on the NRC’s public meeting notification Web site at 

http://meetings.nrc.gov/pmns/mtg. The NRC staff also e-mailed meeting notices to the 

YMEIS_supplement@nrc.gov distribution list. 

Table B-1. Draft Supplement Public Comment Meeting Summaries and Transcripts

Meeting Date Meeting Location 

Meeting Summary 

(Accession No.) 

Meeting Transcript 

(Accession No.) 

September 3, 2015 Rockville, Maryland ML15253A663 ML15253A669 

September 15, 2015 Las Vegas, Nevada ML15272A405 ML15268A399 

September 17, 2015 Amargosa Valley, Nevada ML15280A279 ML15274A168 

October 15, 2015 Teleconference ML15302A184 ML15294A368 

November 12, 2015 Teleconference ML15321A424 ML15321A414 

The NRC staff extended the original close of the public comment period from October 20, 2015, 

to November 20, 2015 (80 FR 56501), and added an additional public comment teleconference 

on November 12, 2015. 

B.1.2 Public Comments on the Draft Supplement 

During the public comment period for the draft supplement, the NRC staff received over 

1,200 individual comments from 5 transcribed public meetings and more than 140 comment 

letters. All comment correspondence is available in ADAMS and on www.regulations.gov under 

docket ID NRC–2015–0051. The transcripts are available in ADAMS as indicated in Table B-1. 

B.1.3 Disposition of Comments 

At the conclusion of the comment period, the NRC staff reviewed the five public meeting 

transcripts and each comment letter. Many statements from public meetings or individual 

comment letters contained multiple individual comments, which were captured and processed 

separately, as appropriate. Each statement from a public meeting or comment letter was given 

a unique correspondence identification number, allowing the set of comments from a 
B–3 

commenter to be traced back to the transcript or comment letter in which the comments 

were recorded. 

Table B-3 provides a list of individuals who submitted written and oral comments. The comment 

authors are identified by name, affiliation (if given), ADAMS accession number of their comment 

letter or the public meeting transcript, and the comment correspondence identification number. 

Each comment was assigned to a specific subject area (see Table B-2 for the list of comment 

categories), and similar comments were further grouped together and summarized. Finally, 

responses were prepared for each comment summary. This appendix contains comment 

summaries and the NRC staff responses to these summaries. 

When comments resulted in a change to the text of the supplement, the corresponding 

response refers readers to the appropriate section of the supplement where the change was 

made. Throughout the final supplement—with the exception of this new Appendix B—revisions 

to the text from the draft supplement are indicated by vertical lines (change bars) in the margin 

beside the text. In addition, the NRC staff revised entries in the tables of Chapter 3 to reflect 

peak values (e.g., during the million-year period) instead of only providing values at the end of 

the period, as well as to reflect updated values based upon the NRC staff’s consistency 

review of the analyses. The staff also revised low-income and minority population entries 

in Tables 3-18 and 3-19 to account for more recent data and to correct errors in the 

draft supplement. 

The NRC staff categorized and consolidated comments according to subject area. Table B-2 

lists the comment categories (i.e., subject areas) and the page where each general 

category begins. 

Table B-2. Comment Categories 

B.2 Comments and Responses ....................................................................................... B–4

B.2.1 NEPA Process ................................................................................................... B–4

 B.2.1.1 Public Process .................................................................................... B–4

 B.2.1.2 NEPA Process and the Supplement Supplement Scope ................... B–7

 NEPA Process .................................................................................. B–15

 Miscellaneous ................................................................................... B–25

 Other Process Concerns .................................................................. B–25

 B.2.2 Supplement Assumptions ................................................................................ B–29

 B.2.2.1 Climate and Long Timeframes .......................................................... B–29

 B.2.2.2 Total System Performance Assessment and 

 Other Modeling ................................................................................. B–34

 B.2.2.3 Repository Inventory, TADs, Drip Shields ........................................ B–43

 B.2.3 Affected Environment ...................................................................................... B–47

 B.2.3.1 General Scope .................................................................................. B–47

 B.2.3.2 Water Resources .............................................................................. B–49

B.2.4 Environmental Impacts .................................................................................... B–56

 B.2.4.1 Water Resources .............................................................................. B–56

 B.2.4.2 Public and Occupational Health ....................................................... B–69

 B.2.4.3 Ecological Resources ....................................................................... B–75

 B.2.4.4 Historic and Cultural Resources ....................................................... B–77

 B.2.4.5 Environmental Justice ...................................................................... B–79

 B.2.4.6 Other Topics ..................................................................................... B–84

 Socioeconomics ............................................................................... B–84

 General Safety Concerns ................................................................. B–85
B–4 

Table B-2. Comment Categories 

 Transportation ................................................................................... B–86

 Seismic and Volcanic Events ............................................................ B–88

B.2.5 Cumulative Impacts ......................................................................................... B–89

 B.2.6 Other Topics .................................................................................................... B–96

B.2.6.1 Miscellaneous ................................................................................... B–96

 B.2.6.2 General Opposition ......................................................................... B–108

 B.2.6.3 General Support ............................................................................. B–111

B.2 Comments and Responses 

The following sections include summaries of the comments received on the draft supplement 

and responses to those summaries. Parenthetical numbers after each comment and response 

refer to the correspondence identification number. Comments can be tracked from the 

commenter and the source document through the correspondence identification numbers listed 

in Table B-3. 

B.2.1 NEPA Process 

B.2.1.1 Public Process 

B.2.1.1.1 COMMENT: Many commenters requested an extension to the comment period 

for the draft supplement. Commenters expressed concern that the 60-day comment period 

provided for in the Federal Register Notice was insufficient to allow for the public to review the 

supplement and other documents in order to understand and comment on the supplement. 

Some commenters felt that the length of the comment period provided an advantage to the 

NRC. One commenter expressed concern that the comment period was too short when 

considering the very long timeframes addressed in the supplement. Some commenters 

expressed concern about the length of time that it takes for grassroots organizations to reach 

out to their communities and encourage participation, and about the lack of resources available 

to give their staffs adequate review time. Following the NRC’s extension of the comment period 

by 31 days, the NRC received additional comments expressing appreciation for the extension, 

disappointment in the length of the extension, and requesting additional extensions.

RESPONSE: The NRC staff acknowledges the concerns expressed by commenters about the 

length of the comment period. In response to requests received to extend the comment period, 

the NRC staff extended the original 60-day comment period to 91 days. Because of the limited 

scope of the supplement, the NRC staff believes that 91 days is sufficient time for members of 

the public to review the document and prepare comments. During the comment period, the 

NRC staff held five public meetings to explain the purpose and scope of the document, answer 

questions about the process, and to receive comments. The NRC staff appreciates the 

considerable number of comments that were received, and each of the comments was taken 

into consideration in the preparation of the final supplement. Appendix B contains the NRC 

staff’s consideration and response to the comments received on the draft supplement. 

(013, 014, 018, 022, 028, 031, 039, 040, 047, 053, 054, 055, 071, 075, 078, 080-16, 083, 085, 

092, 093, 094, 101, 104, 107, 110, 111, 112, 130, 141, 146-01, 146-02, 146-05, 146-06, 146-07, 

146-13, 147-03, 147-13, 147-14, 147-24, 150) 
B–5 

B.2.1.1.2. COMMENT: Several commenters expressed appreciation for the NRC’s holding 

of public meetings, particularly in-person meetings, seeking public input on the draft 

supplement, and listening to the public’s concerns. Some commenters stated that it is important 

to exchange ideas, gain a better understanding of the topic, and for the voices of the 

stakeholders to be heard. One commenter noted that the NRC had provided extensive public 

participation opportunities. 

RESPONSE: The NRC staff acknowledges the comments in support of the public meetings 

that were held for this supplement. The NRC staff agrees that stakeholder input is vital to the 

NRC’s decisionmaking process and appreciates the time and effort that stakeholders took to 

participate. Appendix B contains the NRC staff’s consideration and response to the comments 

received on the draft supplement. 

(034, 080-15, 095-03, 095-06,127, 143, 146-02, 147-02, 147-03, 147-04, 147-08, 147-17, 

147-29, 148) 

B.2.1.1.3. COMMENT: Many commenters requested that additional public meetings be 

held in California and elsewhere across the country. Most of these commenters requested that 

these meetings be held near the transportation routes that could be used for shipment of spent 

nuclear fuel to the repository. Commenters requested a call-in option at all public meetings. 

One commenter asked if the reason for not holding public meetings on the supplement in 

California was due to lack of funding or because of lack of consideration for the area. 

RESPONSE: The NRC staff acknowledges the comments requesting additional public 

meetings and regrets that time and resources did not allow for public meetings to be held in 

every location requested by commenters. The NRC staff attempted to maximize participation in 

the public meetings by holding meetings at NRC headquarters that were accessible by 

teleconference, local meetings in Las Vegas and in Amargosa Valley, and two additional public 

teleconference meetings. Because the scope of this supplement is limited to impacts from the 

potential repository on groundwater and from surface discharges of groundwater at points 

beyond the postclosure compliance location, meeting locations were limited to areas near the 

potentially affected environment. Las Vegas was selected because it is the closest major 

population center near the affected environment. Amargosa Valley was selected because it is 

among the areas directly affected by the impacts discussed in the supplement and is within a 

few miles of the California/Nevada border. Commenters were also able to submit comments 

electronically. In response to comments, the NRC staff also extended the comment period from 

60 to 91 days. From participation in public meetings and comment letters, the NRC received 

over 1,200 comments on the draft supplement. 

No changes were made to the supplement as a result of these comments. 

(013, 014, 022, 028, 031, 039, 040, 047, 053, 054, 055, 071, 075, 076, 078, 080-05, 80-16, 083, 

085, 092, 093, 094, 101, 104, 107, 112, 146-07, 146-14, 147-15, 150) 

B.2.1.1.4. COMMENT: Two commenters expressed concern that many citizens and public 

officials are not sufficiently aware of the supplement and other NRC-related activities. One 

commenter stated that it is incumbent on the government to notify elected officials. Another 

commenter stated that it seems very few people are interested and may not realize the 

seriousness of the matters discussed. 
B–6 

RESPONSE: The NRC staff acknowledges the concern that some citizens and public officials 

may not be fully aware of the NRC’s activities. The NRC staff strives to provide clear and timely 

notification to affected units of local government and other stakeholders to maximize 

participation in public comment processes. Consistent with NRC practices, the supplement 

includes a distribution list for the supplement (Chapter 9). When the draft supplement was 

published, all individuals on the Yucca Mountain adjudicatory distribution list were notified, as 

well as many other individuals and organizations. In addition, the NRC issued a press release 

noting the availability of the supplement. 

The NRC staff agrees that public participation is vital to the NRC’s decisionmaking process and 

encourages interested stakeholders to view public participation opportunities on the NRC’s 

Web site at http://www.nrc.gov/public-involve.html. 

No changes were made to the supplement as a result of these comments. 

(095-02, 095-10) 

B.2.1.1.5. COMMENT: Two commenters asked about the availability of information 

regarding the supplement and public meetings or about use of the www.regulations.gov. One 

commenter asked where to find transcripts of the public meetings and another asked where to 

find the slides from the teleconferences on the NRC Web site. One of the commenters also 

asked about technical issues with use of the www.regulations.gov Web site, including issues 

with tracking comments on the site, the allotted space for a comment, and determining if a 

comment has been received. 

RESPONSE: Information about the supplement, including the public meetings summaries, 

meeting materials, and transcripts can be found on the NRC’s Web site at 

http://www.nrc.gov/waste/hlw-disposal/key-documents.html#er. The NRC staff regrets that 

commenters may have experienced difficulties with the regulations.gov Web site. All comments 

the NRC received on the draft supplement are accounted for in this appendix. 

No changes were made to the supplement as a result of these comments. 

(080-07, 122, 146-10) 

B.2.1.1.6. COMMENT: Several commenters expressed concern or disappointment with the 

NRC’s public participation opportunities. One commenter asserted that their organization had 

not had any say in changes made to the nuclear waste program since DOE’s Environmental 

Impact Statement (EIS) was published. Another commenter stated that the public has struggled 

to participate in the NRC’s processes and obtain information. One commenter stated that NRC 

should be more sensitive about scheduling public meetings on or close to religious holidays. 

Another commenter was disappointed that the format of the meeting did not allow for a technical 

dialogue among participants. 

RESPONSE: The NRC staff acknowledges the comments concerning the public participation 

opportunities and recognizes the vital importance and value of stakeholder participation in the 

NRC’s decisionmaking process. The NRC staff has attempted to provide ample notification of 

the availability of the draft supplement for comment, extended the public comment period to 

allow more time for commenters to provide their input, and provided multiple avenues for 

comment submission (online, in-person, by mail, and by teleconference). The NRC staff has 
B–7 

also attempted to maximize participation in public meetings by providing teleconference lines at 

several meetings, providing informational presentations at all public meetings, and holding open 

houses at the Nevada-area public meetings prior to the formal meeting. The NRC staff 

recognizes the importance of religious holidays and attempts to schedule meetings so as not to 

interfere with religious holidays, Federal holidays, or local events. 

With regard to opportunities for public participation in the nuclear waste program since the 

publication of DOE’s EIS, the preparation of this supplement is only one of several steps in the 

licensing process for the proposed repository. As discussed in Section 1.1 of the supplement, 

the adjudicatory proceeding for the proposed repository is currently suspended. The completion 

of licensing activities is subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(080-10, 122, 146-03, 146-17, 147-12) 

B.2.1.2 NEPA Process and the Supplement Scope 

B.2.1.2.1. COMMENT: Two commenters stated that the NRC should have conducted 

public scoping for the draft supplement. One commenter cited changed circumstances, the 

controversial nature of the Yucca Mountain project, and the passage of 7 years since the 

development of the NRC staff’s Adoption Determination Report (ADR), as reasons to have 

conducted scoping. Another commenter stated the supplement does not acknowledge a 

January 20, 2015 letter from the Board of Lincoln County Commissioners to the NRC 

(Lincoln County, 2015) requesting additional scoping for the draft supplement. The commenter 

argued that the final supplement must disclose how any such comments may have influenced 

the supplement’s scope.

RESPONSE: The NRC staff disagrees that additional scoping should have been conducted for 

the supplement. Section 3.2.1.4.2.3 of the ADR states: “(g)iven the description in this report of 

the needed supplementation, and pursuant to 10 CFR 51.26(d), the staff would not conduct 

scoping for the supplement.” The NRC Chairman responded to the Chair of the Board of 

Lincoln County Commissioners by a letter dated March 9, 2015 (NRC, 2015d). In the letter, the 

Chairman stated that the scope of the EIS was determined by DOE with full public involvement, 

including public scoping meetings and the publication of a draft EIS for notice and comment, 

and the scope was adopted by the NRC staff. The Chairman noted that the public was provided 

the opportunity to challenge the scope of the NRC staff’s analysis by raising contentions before 

the agency’s Atomic Safety and Licensing Board. 

The letter also explains that the staff prepared the supplement at the direction of the 

Commission after the U.S. Court of Appeals for the District of Columbia Circuit issued its 

decision in Aiken County, 725 F.3d 255 (D.C. Cir. 2013). The Court directed the NRC to 

continue its licensing activities and use previously-allocated funds from the Nuclear Waste 

Fund. Once these funds are expended, the continuation of licensing activities is subject to 

Congressional appropriations and actions external to the NRC. Additional information 

concerning changed circumstances since DOE’s EISs and the ADR were finalized can be found 

in comment responses in Sections B.2.1.2.6, B.2.1.2.29, and B.2.2.3.1. 
B–8 

No changes were made to the supplement as a result of these comments. 

(118, 123) 

B.2.1.2.2. COMMENT: One commenter made several comments describing why the scope 

of the supplement is appropriate. The commenter stated that the scope is consistent with the 

areas defined in the NRC staff’s ADR, NRC regulations in 10 CFR 51.109(c), and Supreme 

Court and Commission precedent. 

RESPONSE: The NRC staff acknowledges the comments in agreement with the scope of 

the supplement. 

No changes were made to the supplement as a result of these comments.

(143)

B.2.1.2.3. COMMENT: One commenter stated that the scope of the supplement is 

insufficient because it does not consider that costs may have changed since DOE developed its 

EIS. The commenter noted that on-site storage costs at San Onofre have exceeded the 

industry’s estimates. 

RESPONSE: Comments regarding costs for on-site storage of spent fuel or high-level waste, or 

costs of a repository, are beyond the scope of this supplement, which concerns an assessment 

of the potential impacts to groundwater and from surface discharges of groundwater beyond the 

postclosure compliance location. The scope of the supplement is further described in the 

NRC staff’s ADR (NRC, 2008a), and in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029). 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of this comment. 

(080-15) 

B.2.1.2.4. COMMENT: Several commenters stated that the draft supplement is deficient 

because it artificially constrains the scope to a single issue. Others said the NRC erroneously 

eliminated issues that it considered previously and, therefore, failed to look at the whole picture. 

One commenter stated the NRC did not take a hard look at the national transportation 

infrastructure, including Federal regulations on the deterioration of rail infrastructure. 

Another commenter stated the NRC should consider the issues of high-burnup fuels and 

transportation canisters.

RESPONSE: The NRC staff acknowledges the concerns raised about the limited scope of this 

supplement. The scope of the supplement is an assessment of the potential impacts to 
B–9 

groundwater and from surface discharges of groundwater beyond the postclosure compliance 

location, as described in detail in the NRC staff’s ADR (NRC, 2008a) and the NRC’s Notice of 

Intent to prepare the supplement (80 FR 13029). 

The NRC Chairman stated in a letter to the Chair of the Board of Lincoln County Commissioners 

that participants in the adjudication may pursue their contentions before the Atomic Safety and 

Licensing Board, as well as raise new issues as new or amended contentions, upon resumption 

of the hearing (NRC, 2015d). The preparation of this supplement is only one of several steps in 

the NRC’s licensing process for the proposed repository. Information may be identified in the 

future that requires further supplementation of DOE’s 2002 and 2008 EISs. The completion of 

licensing activities is subject to Congressional appropriations and other actions external to the 

NRC. Specific comments about transportation are addressed in Sections B.2.4.6.6 and 

B.2.6.1.22 and comments about high-burnup fuels are addressed in Sections B.2.1.2.29, 

B.2.2.3.2, and B.2.6.1.23. 

No changes were made to the supplement as a result of these comments. 

(080-05, 080-08, 080-15, 146-02, 148) 

B.2.1.2.5. COMMENT: Two commenters made general statements that the scope of the 

document is too narrow. One of the commenters stated that the only areas that NRC found to 

critique are with regard to land ownership and water rights.

RESPONSE: The NRC disagrees that the scope of the supplement is too narrow. The NRC 

staff identified the scope as a result of the staff’s review of the DOE EISs, as documented in the 

NRC staff’s ADR. That assessment defined two areas that needed supplementation: the 

potential impacts to groundwater and from surface discharges of groundwater beyond the 

postclosure compliance location. The scope of this supplement is further described in the 

NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). 

The commenter is correct that the NRC staff identified land ownership and water rights as areas 

of deficiency in DOE’s license application. These deficiencies were identified in the NRC staff’s 

safety review, as documented in the NRC staff’s SER. The NRC staff concluded in the SER 

that DOE had not met regulatory requirements regarding ownership and control of certain land 

and water rights. Additional information about the results of the safety review can be found in 

Volume 5 of the SER (NRC, 2015b). 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(146-07, 147-21) 

B.2.1.2.6. COMMENT: Several commenters stated that the supplement and DOE’s EISs 

need to be updated to reflect current science, data, and circumstances. The commenters stated 

that the narrow scope defined by the NRC staff’s ADR deserves reconsideration under NRC 
B–10 

regulations in 10 CFR 51.92 due to changed circumstances and new information that has arisen 

since 2008. Another commenter cited 10 CFR 51.109(c)(2), addressing “significant and 

substantial new information or new considerations,” and the ADR’s application of this regulation. 

One commenter also called for the NRC to develop a new safety evaluation report for the 

proposed repository. One commenter asked if the conclusions in the supplement are based on 

a “recycle of old data.” Another commenter stated that the entire licensing process should 

restart from the beginning. 

RESPONSE: The NRC staff acknowledges these comments requesting that the supplement 

and DOE’s documents be updated to reflect new information or changed circumstances since 

2008. This supplement concerns an assessment of the potential impacts from the proposed 

repository to groundwater and from discharges of groundwater at locations downstream of the 

postclosure compliance point. The NRC staff did not identify any new information about the 

affected environment beyond the postclosure compliance point pertinent to the scope of the 

supplement. However, the preparation of this supplement is one of several steps in the 

licensing process for the proposed repository. Information may be identified that requires 

further supplementation of DOE’s 2002 and 2008 EISs in the future. The completion of 

licensing activities is subject to appropriations and other actions external to the NRC. 

Some of the commenters gave specific examples of developments since 2008, and these are 

addressed in further detail in Sections B.2.2.3 (repository inventory and canisters); B.2.1.2.29, 

B.2.2.3.2, and B.2.6.1.23 (high-burnup spent fuel); and B.2.1.2.6 (changed circumstances). 

No changes were made to the supplement in response to these comments. 

(116, 118, 121, 128, 141, 146-06, 147-23, 147-24, 148, 149-03, 149-10, 149-20) 

B.2.1.2.7. COMMENT: One commenter stated that the scope of the analysis (the 

timeframe of 1,000,000 years) is too broad, the methodology of the analysis is not quantifiable, 

and the document is confusing and lacks structure. 

RESPONSE: The NRC staff disagrees with the comment. Responses to comments about the 

timeframe are provided in Section B.2.2.1. The methodology for the analysis, as described in 

Chapter 3 of the supplement, employs modeling and other analysis techniques commonly used 

in environmental impact statements and other NEPA documents. The structure of the 

document is based on NUREG-1748, “Environmental Review Guidance for Licensing Actions 

Associated with NMSS Programs” (NRC, 2003). However, there are some differences in the 

structure of this supplement compared to other NRC environmental review documents due to 

the narrow scope of this supplement and because it supplements DOE EISs pursuant to an 

NRC regulation developed to address the NRC’s environmental review process specifically for 

the Yucca Mountain repository (10 CFR 51.109) (NRC, 2003). 

No changes were made to the supplement as a result of this comment. 

(020) 

B.2.1.2.8. COMMENT: A few commenters expressed their concerns about the 

supplement’s consideration of institutional controls for the proposed repository and the 

assumptions about institutional controls at storage sites in the no-action alternative scenarios in 

DOE’s EISs. Some comments stated that the supplement is insufficient, because it fails to 
B–11 

update DOE’s assessment of a no-action alternative. The comments discussed the two 

scenarios in the DOE EISs, which include Scenario 1 (long-term storage of spent fuel at reactor 

and storage sites with institutional controls present) and Scenario 2 (long-term storage with loss 

of institutional controls). The comments asserted that the proposed action (construction of a 

repository at Yucca Mountain) was chosen because the Scenario 2 alternative would have large 

impacts by comparison. The comments also stated that the NRC’s Generic EIS for Continued 

Storage (NUREG-2157) states that the no-action alternative Scenario 2 is contrary to the rule of 

reason and violates NEPA. The comments conclude that if Scenario 2 is eliminated from 

consideration, Yucca Mountain is not the preferred alternative under NEPA. Another 

commenter stated that the validity of the no-action alternative scenario in DOE’s EIS that 

assumes no institutional controls is out of scope for this supplement, because the NRC staff did 

not raise this as an issue as a result of the staff’s 2008 EIS adoption review. The commenter 

also states that DOE’s other no-action scenario and the NRC’s evaluations in the Waste 

Confidence EIS (Continued Storage GEIS) adequately address the Yucca Mountain no-action 

scenarios, and no further evaluation is necessary. Another commenter stated that the NRC 

mistakenly relies on institutional controls within the compliance boundary to protect the public 

from the impacts of contamination, whether those controls are active or passive.

RESPONSE: The comments regarding the consideration of institutional controls in DOE’s EISs, 

the alternatives and no-action alternative in DOE’s EISs, institutional controls at storage sites, 

and the evaluations in the NRC’s Continued Storage GEIS (NUREG-2157) are beyond the 

scope of this supplement. The supplement concerns an assessment of the potential impacts to 

groundwater and from surface discharges of groundwater beyond the postclosure compliance 

location. The scope of this supplement is further described in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029), and in the NRC staff’s ADR (NRC, 2008a). The 

alternatives to the proposed repository are discussed in DOE’s 2002 and 2008 EISs, including 

institutional controls. The NRC staff’s ADR concluded that it is practicable to adopt DOE’s EISs 

(with supplementation related to groundwater impacts beyond the postclosure compliance 

location), and the NRC staff’s review did not identify the need for supplementation concerning 

alternatives or institutional controls at the repository site. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. As stated in Section 1.4 of the supplement, the supplement does not 

represent a change to the proposed action or alternatives presented by DOE. However, 

information may be identified that requires further supplementation of DOE’s 2002 and 2008 

EISs in the future. The completion of licensing activities is subject to appropriations and other 

actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(132, 138, 141, 146-06, 148) 

B.2.1.2.9. COMMENT: Three commenters raised questions or concerns about the 

alternatives considered in the supplement. Two of the commenters stated that a NEPA analysis 

would include an evaluation of alternatives to determine the best solution and with consideration 

of all relevant environmental factors. One commenter expressed concern that, because 

Yucca Mountain is the only site under consideration, the NEPA analyses for the proposed 

repository justify a foregone conclusion. Another commenter questioned whether other sites 

had been considered as alternatives to Yucca Mountain, or whether Yucca Mountain was the 

only site considered. 
B–12 

RESPONSE: The analysis of alternatives is included in the DOE EISs for Yucca Mountain, 

which were assessed and adopted by the NRC staff, consistent with the Nuclear Waste Policy 

Act of 1982, as amended (NWPA), and with NRC regulations (10 CFR 51.109). The NRC 

staff’s adoption of DOE’s EISs is documented in its ADR (NRC, 2008a), which specified two 

areas that needed supplementation: impacts to groundwater and from surface discharges of 

groundwater beyond the repository compliance location. These areas constitute the scope of 

this supplement. As noted in Section 1.4 of the supplement, the supplement does not represent 

any change to the alternatives identified by DOE in its EISs. The NWPA, as amended, specifies 

Yucca Mountain as the only site for consideration and states in Section 114(a)(1)(D) that 

additional alternative sites need not be considered. 

No changes were made to the supplement as a result of these comments. 

(118, 146-04, 149-10) 

B.2.1.2.10. COMMENT: Three commenters provided input with regard to tribal consultation. 

One commenter quoted the draft supplement on page 4-20 to note that meaningful and ongoing 

tribal consultation is important. Another commenter pointed to the supplement’s conclusion in 

Section 3.3 that “DOE would need to assess whether further consultation and investigation are 

necessary to account for potential impacts on cultural resources that may be located in areas 

where groundwater discharges to the surface,” noting that this statement indicates the 

supplement evaluation is incomplete, and inquiring whether the staff plans to further address 

the issue. 

Another commenter highlighted the same conclusion in Section 3.3 of the supplement and 

noted the similar conclusion in Section 4.5.2.3 (page 4-19) of the supplement. The commenter 

stated that the supplement improperly excludes an analysis of the Timbisha Shoshone Tribe’s 

interests in California, and that deferring such an analysis to an unknown future time prevents 

the tribe from meaningfully evaluating the supplement and presents the possibility that the 

analysis may never be conducted. The commenter cited a court decision [Conner v. Burford, 

848 F.2d 1441, 1452 (9th Cir.1988)] in arguing that this exclusion is in violation of NEPA, 

because proceeding with the project without the information that would be provided by such an 

analysis amounts to conducting an interim action that could prejudice the ultimate decision on 

the project. The commenter concludes that, without this analysis, the Timbisha Shoshone 

Tribe’s statutory rights to be consulted on these impacts is denied. 

One commenter further noted that the supplement acknowledges that the Programmatic 

Agreement in place to govern project-related compliance under the National Historic 

Preservation Act is limited in scope to the repository site and the surrounding controlled area 

(i.e., the Project Operator-Controlled Area). The commenter pointed out that the Programmatic 

Agreement was executed in 2009 with a 10-year duration and includes a statement that impacts 

outside the Operator-Controlled Area are outside the scope of the Agreement and need to be 

considered separately. The commenter stated that the affected area in Nevada and California 

covered by the supplement is larger than the area covered by the Programmatic Agreement, 

and that the draft supplement is lacking an analysis of the short-term and long-term project 

effects in areas not covered by the Agreement. 

RESPONSE: The NRC staff disagrees that its supplement is incomplete. However, the staff 

recognizes that tribes may not have had the opportunity to fully consult with DOE on potential 

impacts to cultural and historical resources at groundwater discharge locations because these 

areas were not fully considered in DOE’s EISs. Section 3.3 of the supplement describes DOE’s 
B–13 

activities related to tribal consultations and cultural and historic resources under the National 

Historic Preservation Act (NHPA) and DOE’s Native American Interaction Program. The NRC 

staff also notes the commitment DOE made in its EISs to complete these activities for impacted 

areas within the scope of the proposed repository. The supplement also describes DOE’s 

programmatic agreement with the Advisory Council on Historic Preservation and the Nevada 

State Historic Preservation Office. The NRC staff’s supplement addresses groundwater 

discharge areas that were not specifically addressed in DOE’s EISs or in the executed 

programmatic agreement. 

As stated in Section 4.1 of the staff’s ADR, DOE is the lead agency responsible for these 

activities. As stated in Section 2.3.2 of the supplement, cultural and historic resources may be 

located in or around these discharge areas. As noted in Section 3.3.5 of the supplement, DOE 

would need to assess whether further consultation and investigation are necessary to account 

for potential impacts on cultural resources that may be located in areas where groundwater 

discharges to the surface. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified related to the commenters’ concerns that 

requires further supplementation of DOE’s 2002 and 2008 EISs in the future. The completion of 

licensing activities is subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(060, 080-04, 136)

B.2.1.2.11. COMMENT: One commenter expressed a number of concerns about the 

evaluation of impacts documented in the supplement and in the DOE EIS documents of 2002 

and 2008. Specific concerns addressed compliance of the supplement and DOE EISs with 

court rulings and regulations of the Council on Environmental Quality for implementation of 

NEPA, and the potential synergistic effects of metals (specifically, Cr6+ and V5+) and 

radionuclides on the environment and human health. 

RESPONSE: The supplement was prepared in accordance with NEPA, the NRC’s regulations 

that implement NEPA in 10 CFR Part 51, and staff guidance in NUREG-1748 (NRC, 2003). The 

staff’s review of DOE’s EISs is given in its ADR (NRC, 2008a), which discusses the basis for the 

adoption under 10 CFR 51.109, and the need for supplementation on the specific issues 

addressed in the supplement. 

The supplement did not examine synergistic effects of metals and radionuclides, as these are 

unlikely due to the very low concentrations of the metals of interest calculated for the 

groundwater system. While it is correct that large amounts of metals, such as Cr and V, are 

present in the engineered materials of the repository, the metals would enter the groundwater 

system very slowly (corresponding to the slow corrosion rates) and result in low groundwater 

concentrations, as evaluated by the NRC staff in the SER (NRC, 2014a; Section 2.2.1.3.1). 

Even using the very conservative assumption in the supplement that all of the metal in the 

repository would ultimately be corroded and released, the calculated groundwater 

concentrations and from surface discharges of groundwater remain very low (see Section 3.1 

and a discussion of the NRC staff’s release model in Appendix A, Section A.1.1). The potential 

synergistic effects cited by the commenter appear to occur at much higher metal concentrations 

and radiation doses than would be present in the groundwater environments evaluated in the 

supplement. 
B–14 

No changes were made to the supplement as a result of these comments. 

(116, 147-12) 

B.2.1.2.12. COMMENT: Two commenters stated that the supplement should be revised to 

recognize and incorporate applicable Nevada and California State laws into the analysis. One 

commenter cited Nevada water statutes [Nevada Revised Statutes (NRS) 532, 533, 534, and 

445A] and the Nevada Water Pollution Control Law (enacted at NRS 445A; Sections 445A.400, 

445A.405, 445A.415, and 445A.465), which the commenters stated collectively prohibit the 

discharge of radioactive materials into groundwater and the “artificially induced alteration” of the 

radiological integrity of groundwater. Another commenter stated that these laws provide 

protection beyond the regulations for the Clean Water Act and Safe Drinking Water Act and may 

not be preempted by Federal law. The commenter argued that the supplement should include a 

discussion of these laws and associated permitting requirements and should address 

groundwater impacts at the repository site rather than at a location 11 miles from the repository. 

The commenter also stated that an analysis of the project with respect to California laws on 

water quality and water rights is needed, because impacts to groundwater and surface 

discharge areas in the Death Valley area may occur. The commenter cites the California Water 

Code (§§ 13000, et. seq., Porter-Cologne Water Quality Act) and Article 10 Section 2 of the 

California Constitution. One of the commenters also stated that the supplement should account 

for how the scarcity of water in Nevada could exacerbate the impacts from contamination from 

the proposed repository, further limiting potential beneficial uses. 

One commenter also noted that the Yucca Mountain project may be required to have stateissued permits for discharges to surface waters and groundwaters of the State, including 

permits covering such activities as stormwater management, de minimis discharges, pesticide 

use, drainage wells, groundwater discharges, wastewater discharges, sewage management, 

underground injections, and other similar activities. The commenter also said that, additionally, 

DOE will be responsible for obtaining all other Federal, State, or local permits that may be 

required. 

RESPONSE: DOE compliance with State laws and permits are beyond the scope of this 

supplement, which concerns an assessment of the potential impacts to groundwater and from 

surface discharges of groundwater beyond the postclosure compliance location. The scope is 

further described in the NRC staff’s ADR (NRC, 2008a) and in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029). 

The scope of the supplement does not include impacts on site at the repository, which were 

evaluated in the DOE EISs. In Chapter 11 of both the 2002 and 2008 EISs, DOE evaluated 

compliance with the Safe Drinking Water Act, the Clean Water Act, and Nevada statutes 

(including those cited by the commenter), noting that the Nevada primary drinking water 

standards are identical to the national standards. In the 2008 EIS, DOE also acknowledged that 

various permits would need to be obtained to comply with State and Federal laws and identified 

some of the permits that it had already obtained. 

With regard to the request that the supplement discuss the scarcity of water and the potential for 

the scarcity to exacerbate impacts, the description of the affected environment in Chapter 2 of 

this supplement describes in detail the desert environment, current water quality, and water 

uses in the area. Chapter 3 of the supplement describes the impacts that may occur to 

groundwater and the potential contamination that could result from a repository beyond the 
B–15 

postclosure compliance location, as well as the potential different uses of the water under 

different future climate states. Chapter 4 discusses past, present, and reasonably foreseeable 

future actions that could contribute to cumulative impacts associated with the proposed 

repository. Considering amounts of water, baseline water quality, potential for contaminants to 

concentrate, and many other factors, the supplement concluded that the potential impacts to 

groundwater would be small. 

The preparation of this supplement is one of several steps in the repository licensing process. 

Information may be identified that requires further supplementation of DOE’s EISs in the future. 

The completion of licensing activities, however, is subject to appropriations and other actions 

external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(136, 146-69, 148) 

NEPA Process 

B.2.1.2.13. COMMENT: Several commenters requested clarification or made statements 

regarding the licensing process and framework for the Yucca Mountain repository, and how the 

supplement fits within that framework. One commenter requested clarifications in two specific 

areas of the supplement: i) at Page 1-2 Line 6, requesting a summary of why the NRC’s Atomic 

Safety and Licensing Board denied DOE’s request to withdraw the license application; and ii) at 

Page 1-2 Line 19, requesting clarification on why the adjudicatory process remains suspended, 

also stating that it is due to lack of funding. One commenter asked what options stakeholders 

have to challenge the supplementing of documents that are out of date, asking whether an 

opportunity to challenge would be offered if the licensing proceeding were to continue, how the 

public would be notified if the proceeding were to continue, and whether additional parties to the 

proceeding could be added at that time. Another commenter noted that the NRC’s and DOE’s 

legal responsibilities would not be met if the licensing process does not continue and questioned 

how completion of the supplement relates to the hearing process. 

RESPONSE: The NRC staff recognizes the complexity of the process by which DOE would 

obtain a license to construct and operate a repository at Yucca Mountain, though the staff notes 

that these comments are outside the scope of this supplement, which concerns an assessment 

of the potential impacts to groundwater and surface discharges of groundwater beyond the 

postclosure compliance location. The scope of this supplement is further described in the 

NRC’s Notice of Intent to prepare the supplement (80 FR 13029), and in the NRC staff’s ADR 

(NRC, 2008a). 

The licensing process for a repository at Yucca Mountain has two major components, which 

inform the NRC’s regulatory decision: an environmental review and a safety review. The 

framework for the NRC’s environmental review for the repository is defined by NEPA, which 

requires that agencies consider environmental impacts in their decisionmaking. The NWPA 

requires that DOE prepare an EIS for the proposed repository and that the NRC adopt DOE’s 

EIS to the extent practicable. DOE published its final EIS for the repository in 2002 and 

submitted the EIS with its site recommendation to the President of the United States in 2002. In 

2008, DOE published a final supplemental EIS, which it submitted along with its 2002 EIS to the 
B–16 

NRC as part of its license application. The NRC staff reviewed the EISs and issued its ADR in 

September of 2008. As discussed in Section 1.2 of the supplement, the ADR describes the 

scope of this supplement. 

The NRC maintains information about the status of the Yucca Mountain licensing proceeding on 

its Web site at http://www.nrc.gov/waste/hlw-disposal.html. Should the licensing process 

resume, the NRC would notify participants in the adjudication and would also notify the public 

through a press release, announcement on its Web site, E-mail communications, and a Federal 

Register notice. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(046, 080, 149-02) 

B.2.1.2.14. COMMENT: Several commenters asked questions about the NRC staff’s ADR. 

The commenters requested information about the history of the ADR, whether a record of 

decision is available, how the ADR fits into the decisionmaking process, and the qualifications of 

the NRC staff who made the decisions reflected in the ADR. 

RESPONSE: The ADR (NRC, 2008a) was developed by the NRC staff to document the staff’s 

review of DOE’s EISs for the proposed repository at Yucca Mountain. The Nuclear Waste 

Policy Act requires that DOE prepare an EIS for the proposed repository and that the NRC 

adopt DOE’s EIS to the extent practicable. DOE published its final EIS for the repository in 

2002. In 2008, DOE published a final supplemental EIS, which it submitted along with its 2002 

EIS, to the NRC as part of its license application. The NRC staff reviewed the EISs and issued 

its ADR in September of 2008 (NRC, 2008a). The ADR defined the scope of this supplement, 

as discussed in Section 1.2 of the supplement. 

Appendix A of the ADR lists the contributors to the review and their qualifications. A record of 

decision was not issued for the ADR, because it does not represent a final decision by the NRC. 

The NRC’s final decision on the environmental review would follow completion of NRC 

adjudication on the construction authorization, and a record of decision would be issued in 

support of a construction authorization decision. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository; the adjudicatory proceeding is currently suspended. The completion of 

licensing activities is subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(146-02, 146-03, 146-05) 

B.2.1.2.15. COMMENT: Several commenters questioned whether the NRC is playing an 

appropriate role by developing this supplement instead of DOE, and whether a conflict of 

interest therefore exists. Some commenters stated that NRC authorship of the supplement 

compromises the integrity of the document and gives the perception that the regulator is not 
B–17 

independent. One commenter stated that the NRC staff decision to prepare the supplement 

reverses the staff’s previous position, is in contradiction to NEPA, and that the decision was 

made without a reason and without a prior opportunity for public input. The commenter stated 

that this decision violates 10 CFR 63.24(c), which provides that DOE must supplement its EIS to 

account for changes in its proposal or other significant new information, and that the 

Commission had stated that imposing this requirement on DOE was appropriate in the 

circumstances envisioned by the proposed regulation [54 Fed. Reg. 27864, 27867 

(July 3, 1989)]. The commenter also stated that because the information identified in the NRC 

staff’s ADR is an important information gap, the filling of that gap (the authoring of the 

supplement) is equally important. Thus, the commenter concluded, this supplement should 

have fallen into the “new and significant information” meaning of 10 CFR 63.24, which would 

require DOE to develop the supplement and would make the NRC’s authorship unlawful. 

RESPONSE: The NRC staff disagrees that development of the supplement by the NRC staff is 

inappropriate or compromises the supplement or the independence of the NRC in its review of 

the application for the proposed repository. The potential for the NRC to develop an EIS 

supplement for Yucca Mountain is specifically contemplated in 10 CFR 51.109 and is discussed 

in Section 3.2.1.4.2.3 of the staff’s 2008 ADR. Also, as stated in Section 1.1 of the supplement, 

the Commission directed the staff to develop the supplement only after DOE informed the NRC, 

in response to a Commission request, that DOE would not prepare the supplement. 

With respect to public participation, following the August 2013 decision by the U.S. Court of 

Appeals for the District of Columbia Circuit that directed the NRC to resume the licensing 

process for DOE’s license application, the Commission provided an opportunity for participants 

in the adjudicatory proceeding to comment on how to proceed (NRC, 2013). 

Concerning the requirement in 10 CFR 63.24(c) to update the EIS, DOE published a final 

supplement to the 2002 EIS in 2008. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(146-04, 147-02, 147-14, 148, 149-13) 

B.2.1.2.16. COMMENT: One commenter made broad statements that the draft supplement 

violates both the “letter and spirit” of NEPA and the NWPA. The commenter went on to give 

several detailed explanations of their objections to the supplement, including NRC preparation 

of the supplement (instead of DOE); information that the commenter stated was significant new 

information having arisen since the ADR was published in 2008; and other concerns about 

scientific and legal deficiencies. 

RESPONSE: The NRC staff disagrees with the comment. The NRC staff has carefully 

complied with NEPA and the NRC’s NEPA-implementing regulations and guidance in 

10 CFR Part 51 and NUREG-1748 (NRC, 2003) in preparing this supplement. Furthermore, 

the staff prepared the supplement in compliance with the NWPA; this issue is discussed further 

in Section B.2.1.2.15. Issues regarding potential new information are addressed in 
B–18 

Section B.2.1.2.6. The commenter’s other specific objections that followed this general 

statement are captured and addressed in specific topic areas throughout this appendix. 

No changes were made to the supplement as a result of this comment. 

(148) 

B.2.1.2.17. COMMENT: One commenter stated that the NRC previously indicated to the 

Appeals Court for the District of Columbia Circuit that it had limited resources to complete the 

Yucca Mountain license application review. The commenter asked whether sufficient resources 

were available to complete the groundwater analysis in this supplement and stated that if 

resources were not adequate, the NRC should note where additional funding could result in a 

more comprehensive analysis. Another commenter stated that a dissenting opinion in the court 

case in which the NRC was ordered to resume licensing activities [In Re Aiken County, 725 

F.3d 255 (D.C. Cir.2013)] held that the amount of funding available for licensing activities was 

grossly insufficient. The commenter went on to say that the court case had left unresolved 

whether or not the NRC would have sufficient resources to lawfully complete the review 

process, and that regardless of availability of finances, nothing in the court’s majority and 

dissenting opinions excuses any final decisionmaking on Yucca Mountain from fully complying 

with NWPA and NEPA. 

RESPONSE: Comments regarding the funding needed or available to complete the 

Yucca Mountain licensing review are beyond the scope of this supplement, which concerns an 

assessment of the potential impacts to groundwater and from surface discharges of 

groundwater beyond the postclosure compliance location. However, the NRC staff 

acknowledges that limited funds are available to complete the Yucca Mountain license 

application review. The 2013 decision by the Court of Appeals for the District of Columbia 

Circuit ordered the NRC to continue work on licensing activities as long as it had available 

funds. Following the NRC staff’s publication of the SER, sufficient remaining funds were 

available for the staff to develop this supplement. The NRC staff agrees that all license review 

activities must be in accordance with the NWPA and NEPA and has conducted its reviews and 

analyses in accordance with the NWPA and NEPA. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(018, 019, 148) 

B.2.1.2.18. COMMENT: Several commenters stated their objections to the completion of the 

document on a “fast track” or with missing information. Commenters stated the supplement 

schedule prevented a thorough scientific evaluation, did not provide transparency regarding the 

potential impacts, and did not provide an opportunity for meaningful public participation. 

Another commenter noted the NRC’s responsibility to future generations, in the context of 

one-million-year compliance period, is more important than meeting a deadline. One 

commenter cited experiences at the WIPP facility, Savannah River site, and Hanford site as 
B–19 

reasons for careful consideration. Two commenters stated that the supplement is premature 

because not all of the risk factors have been adequately characterized or evaluated. 

RESPONSE: The NRC staff disagrees with commenters that there was not sufficient 

opportunity for public participation on the supplement. With regard to the development of the 

supplement, the NRC staff assessed the time and resources needed to obtain sufficient 

information to complete its required analyses, given the limited scope of the document. 

Furthermore, in recognition that public participation is important to the NEPA process, the NRC 

staff extended the comment period, giving members of the public additional time to evaluate the 

draft supplement and prepare comments. The NRC staff received over 1,200 individual 

comments from 5 transcribed public meetings and more than 140 comment letters.

While experiences at other sites such as WIPP and the Savannah River Site are beyond the 

scope of this document, which concerns groundwater impacts beyond the postclosure 

compliance location, the NRC staff acknowledges the commenters’ concerns and carefully 

evaluated the potential impacts of the proposed repository beyond the postclosure compliance 

location. 

No changes were made to the supplement as a result of this comment. 

(111, 146-02, 146-12, 146-13, 146-16) 

B.2.1.2.19. COMMENT: Several commenters made statements about the lack of funding 

available for affected units of local government (AULGs) and affected Indian tribes to consider 

and comment on the draft supplement. One commenter expressed concern that the Timbisha 

Shoshone, a designated affected tribe, did not receive prior notification that the supplement was 

being issued. The commenter stated that the tribe did not have the time needed nor resources 

available to hire experts to conduct the needed thorough review, especially given the 

importance of potential contamination on tribal lands and the cultural and spiritual importance of 

water to the tribe. The commenter described its efforts to secure funding to conduct a review 

[from the Department of Interior (DOI), NRC, DOE, and the Central California Agency of the 

DOI’s Bureau of Indian Affairs] but noted that it was unsuccessful. The commenter stated that 

the U.S. is bound by its own law to provide additional funding to the Timbisha to conduct a 

review, citing 42 U.S.C. § 10138(b) and 42 U.S.C. § 10199. The commenter described the 

supplement as an “abbreviated effort to assess impacts without meaningful tribal consultation,” 

since no funding was provided. The commenter stated that the Timbisha has full statutory rights 

to consultation, and; therefore, the supplement should be rejected until funding and time are 

granted. The commenter also stated that the NRC cannot defer an assessment of potential 

impacts to Timbisha lands in California, which is discussed in Section B.2.6.1.4 and B.2.6.1.5. 

Two commenters stated that their respective organizations are at a disadvantage without having 

received funding to hire the technical experts necessary to adequately review the document. 

One of these commenters noted that had DOE completed the supplement, AULGs would have 

received funding, and that finalizing the document without proper AULG funding and 

involvement makes a mockery of the intent of NEPA and the intent of Congress in the NWPA. 

One commenter noted that the recent incidents at WIPP in New Mexico illustrate why potential 

impacts should not be viewed so far in the future that they are not important to local 

communities. 

RESPONSE: The NRC staff acknowledges both the lack of funding available for AULGs and 

the concerns that this lack of funding has been a disadvantage to reviews of the supplement. 
B–20 

The Nuclear Waste Policy Act of 1982 provides that the Secretary of DOE shall make financial 

assistance available through grants to the State of Nevada, affected units of local governments, 

and to affected tribes, for the purpose of participating in the licensing process. This funding has 

been used by the State of Nevada, local governmental agencies, and tribes to fund participation 

in DOE’s technical and environmental review process. The NRC is not granted authority under 

the Nuclear Waste Policy Act to provide funding for such participation. For this reason, the NRC 

is not able to provide funding to the State of Nevada, affected tribes, or affected units of local 

government. 

The NRC staff provided its Notice of Intent to prepare the supplement in the Federal Register on 

March 12, 2015 (80 FR 13029). The NRC staff also issued a press release and notified the 

hearing participants and other stakeholders of the supplement’s publication. The NRC staff 

made efforts to meet with members of the Timbisha Shoshone Tribe, including to discuss the 

draft supplement and respond to questions. The NRC staff also held multiple in-person public 

meetings and public teleconferences seeking stakeholder input on the draft supplement. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments.

(019, 060, 073, 138, 147-11, 147-14, 149-05, 149-08) 

B.2.1.2.20. COMMENT: One commenter requested that the NRC consider potential 

groundwater contamination from a holistic perspective. The commenter also requested that 

NRC consider utilizing unconventional land management perspectives by consulting with native 

peoples and protecting their knowledge as a resource. 

RESPONSE: The NRC staff acknowledges the commenter’s concerns regarding the need for a 

thorough analysis of potential groundwater contamination. Some Native American tribes, as 

well as many local governments, have been participants throughout the Yucca Mountain 

licensing process either through formal consultations with DOE, by providing comments on DOE 

and NRC documents, or as parties to the NRC adjudication. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. Additional information about the status of 

tribal consultations can be found in Section B.2.1.2.10. 

No changes were made to the supplement as a result of this comment. 

(026) 

B.2.1.2.21. COMMENT: Two commenters stated that the draft supplement should not be 

finalized until contentions related to the Yucca Mountain licensing process are resolved. One 

commenter referenced a letter dated January 20, 2015, from Lincoln County to the NRC, which 

stated that the supplement should analyze the NEPA issues raised in the contentions that were 
B–21 

admitted in the adjudicatory proceeding and conduct a public scoping process. Because the 

NRC did not include this information in the draft supplement, the commenter requested that the 

final supplement address these NEPA contentions. One commenter stated that the draft 

supplement is not complete and does not satisfy NEPA because the hearing contentions are not 

resolved. The commenter is also concerned that the State of Nevada’s comments on the DOE 

EIS and the draft supplement are not fully addressed. The commenter noted that an accurate 

groundwater analysis is central to an evaluation of the repository’s potential long-term risks. 

The commenter also noted that the NRC staff’s SER does not consider TSPA-related 

contentions and argued that the use of these unresolved assumptions in the supplement 

renders the document invalid. 

RESPONSE: The NRC staff disagrees that all contentions related to the Yucca Mountain 

licensing proceedings must be resolved before the supplement is finalized. The NRC staff 

acknowledges that contentions are currently pending in the suspended Yucca Mountain 

adjudicatory proceeding, including contentions that concern DOE’s EISs. The NRC Chairman 

stated in a letter to the Chair of the Board of Lincoln County Commissioners (NRC, 2015d) that 

participants in the adjudication may pursue their contentions before the Atomic Safety and 

Licensing Board, as well as raise new issues as new or amended contentions upon resumption 

of the adjudication. 

The NRC staff recognizes that groundwater analysis is an important component in evaluating 

the repository’s potential long-term risks. Furthermore, the staff agrees that assumptions about 

the repository, including TSPA results, affect the assessment of impacts to groundwater in the 

supplement. 

A number of commenters raised concerns related to the NRC staff’s use of information from the 

DOE’s Total System Performance Assessment (TSPA), which was part of DOE’s license 

application for the proposed repository at Yucca Mountain and used as a primary input and as 

support for evaluating environmental impacts in this supplement. A discussion of the use of 

modeling in the supplement can be found in Section 1.2.2, Section B.2.2 of this appendix, and in 

Appendix A. The NRC staff’s evaluation of information on these topics, as presented in the 

license application, is contained in the staff’s Safety Evaluation Report (SER) for the Yucca 

Mountain repository license application (NRC, 2014a). As commenters note, several of the 

issues raised by commenters are the subject of contentions pending in the suspended 

adjudicatory proceeding. 

Comments regarding the scope of the supplement are addressed in Section B.2.1.2.1. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities, however, is 

subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(123, 148) 

B.2.1.2.22. COMMENT: One commenter stated that NRC has not taken the “hard look” 

required by NEPA. The commenter stated that the NRC ignored available information on 
B–22 

interactions between metals and radionuclides and did not properly address incomplete 

information, and, thus, violated NEPA, 10 CFR Part 63, and U.S. Supreme Court decisions. 

RESPONSE: The NRC staff disagrees with the comments. The scope of NRC staff’s analysis, 

as stated in the ADR (NRC, 2008a), is an assessment of the potential impacts to groundwater 

and from surface discharges of groundwater beyond the postclosure compliance location. This 

scope is detailed in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029). The 

staff specifically addresses potential metal and radionuclide interactions in Sections B.2.1.2.11, 

B.2.2.2.4, and B.2.2.2.5 of this appendix. 

In addition, the NRC staff complied with the NRC’s NEPA-implementing regulations in preparing 

the supplement. The staff evaluated the information in DOE’s license application and EISs, the 

NRC staff’s SER, and other sources of information. 

The preparation of this supplement is only one of several steps in the licensing process for the 

proposed repository. Information may be identified in the future that could require 

supplementation of DOE’s 2002 and 2008 EISs. The completion of licensing activities is subject 

to Congressional appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(116) 

B.2.1.2.23. COMMENT: One commenter stated that the draft supplement demonstrates a 

lack of scientific rigor. First, the commenter stated that the NRC staff’s June 2015 visit to the 

Yucca Mountain area did not produce information, analyses, conclusions, or a trip report. The 

commenter stated that the trip was undertaken to preempt the accusation that the supplement 

was prepared without a site visit being conducted. Second, the commenter pointed out that 

Figure 2-3 in the supplement is based on a U.S. Geological Survey paper published in 1979, 

suggesting the staff’s analysis of “old” data is insufficient. The commenter further stated that 

relying on this information, which predates the Yucca Mountain license application, does not 

meet the NEPA requirement at 40 CFR 1506.5 that reviewing agencies independently review 

and verify information. Third, the commenter noted that in response to a Freedom of 

Information Act request for the data on which the map in Figure 2-3 is based, both the NRC and 

DOE responded that they do not possess that data, and this calls into question the accuracy 

and basis for relying on the map and figure. 

RESPONSE: The NRC staff disagrees that its analyses are not scientifically rigorous. The 

NRC undertakes in-person visits, as appropriate, to relevant geographic locations to enable 

technical staff to conduct visual inspections of sites and their characteristics. The first-hand 

knowledge obtained from site visits informs NRC staff analyses. 

Figure 2-3 in the supplement is derived from Belcher and Sweetkind, 2010, and references cited 

therein. As noted by the commenter, the information in Figure 2-3 has been used in a variety of 

academic sources since 1979, and the NRC staff finds it appropriate for use in the supplement. 

No changes were made to the supplement as a result of these comments. 

(148) 
B–23 

B.2.1.2.24. COMMENT: Several commenters requested that the supplement undergo an 

independent peer review. Some commenters stated that the draft supplement is subject to the 

Information Quality Act (IQA), as implemented by a January 14, 2005, OMB Bulletin and NRC 

Management Directive Section 3.17, because the supplement is a “highly influential scientific 

assessment” that is “scientifically and technically novel.” Another commenter argued that the 

supplement is influential because it will affect national waste disposal policy and private sector 

decisions on continued storage of spent nuclear fuel. The commenter also noted that NRC 

Management Directive 3.17 states that information “may not be deemed ‘influential’ for the 

purposes of the guidelines ‘because it is limited in its breadth.’” Another commenter stated that 

the NRC was originally the independent reviewer of the DOE EISs; however, this independent 

role was relinquished when the NRC developed the supplement, and, therefore, a separate 

independent review is needed. Other commenters expressed concerns about accountability 

and transparency and requested disclosure of the credentials of the authors and reviewers.

RESPONSE: The supplement was prepared consistent with the IQA and OMB’s guidelines 

concerning peer review. The NRC staff does not find that the supplement is “scientific 

information the agency reasonably can determine will have or does have a clear and substantial 

impact on important public policies or private sector decisions.” (70 FR 2664). The supplement 

provides an assessment of potential impacts to groundwater and from surface discharges of 

groundwater beyond the postclosure compliance location, which extends 11 miles [18 km] 

beyond the Yucca Mountain project site. 

The NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and the NRC staff’s ADR 

(NRC, 2008a) describe the scope of the supplement in greater detail. The subject of the 

supplement is only one of many subject matter areas regarding the proposed repository that 

were analyzed in DOE’s EISs, described in DOE’s license application and associated reports, 

and evaluated in the NRC staff’s SER. Importantly, the preparation of the supplement is only 

one of several steps in the licensing process for the proposed repository. Thus, this limited 

scope supplement will not determine national waste disposal policy or private-sector decisions 

about the storage of spent fuel. 

The NRC staff has not relinquished its role of independent regulator with the development of the 

supplement. The NWPA and NRC’s regulations at 10 CFR 51.109 anticipated the potential role 

for the NRC staff to develop an EIS supplement. The NRC staff has, consistent with 10 CFR 

Part 51, published the draft supplement for public review and comment, revised the supplement 

in response to comments, and published the final supplement to reflect revisions and responses 

in this appendix according to NEPA and the NRC’s NEPA-implementing regulations. The public 

comment process provides accountability and transparency to the public and stakeholders. A 

list of contributors to this document and their credentials is provided in Chapter 8 of this 

supplement. 

No changes were made to the supplement as a result of these comments. 

(034, 124, 141, 146-02, 146-04, 146-05, 146-06, 146-13, 147-04, 148) 

B.2.1.2.25. COMMENT: One commenter stated that DOE’s EIS is a minimalist 

environmental impact statement that ratifies a predetermined, politically driven outcome, and the 

supplement’s reliance on DOE’s information continues this sense of predetermination, even 

though DOE no longer supports construction of the repository. 
B–24 

RESPONSE: The NRC staff disagrees with the comment. The NRC staff reviewed DOE’s EISs 

and determined that, in accordance with the NWPA, it would be practicable to adopt the EISs 

with supplementation to address impacts to groundwater and from surface discharges of 

groundwater beyond the postclosure compliance location. While the NRC staff’s analysis in the 

supplement relies in part on information provided by DOE, the NRC staff utilized multiple 

sources of information and conducted an independent evaluation, as documented in the 

supplement, to reach its conclusions. 

No changes were made to the supplement as a result of this comment.

(148) 

B.2.1.2.26. COMMENT: Several commenters expressed concern with the impact 

determination descriptions used in the supplement, particularly the use of the term SMALL to 

describe impacts. Some commenters requested the use of quantitative rather than qualitative 

terms, with one commenter requesting that NRC explain why qualitative terms are appropriate 

and provide qualitative descriptions of the impacts. Another commenter stated that the 

definition of small varies among NRC NEPA documents, and requested clarification on how the 

determination relates to established regulatory limits. One commenter stated that use of the 

term SMALL has political implications and would be used by some parties to imply that there is 

no risk. One commenter, using a few examples in the document, stated that the term SMALL 

would be more accurate as “small and insignificant,” or should be described as not detectable or 

very minor, so as not to destabilize or alter the resource. The same commenter also requested 

that NRC note that SMALL impacts do not require mitigation. Another commenter disagreed 

with the use of the term SMALL, stating that the supplement ignores devastating effects the 

repository would have on the Timbisha Shoshone Tribe’s way of life, and that calling the 

impacts SMALL is contrary to NEPA, the NWPA, and the NRC’s implementing regulations. 

Some of the comments also included statements about use of existing data, or radiological and 

toxicological effects. 

RESPONSE: The NRC staff acknowledges the commenters concerns about the way the 

impacts are described in the supplement. The terminology used in the supplement for impacts 

is consistent with NRC regulations (10 CFR Part 51) and guidance (NRC, 2003) for 

environmental impact assessments. To guide its assessment of environmental impacts for a 

proposed action or alternative actions, the NRC established standards of significance for 

environmental impacts using the CEQ terminology for significance (see 40 CFR 1508.27). 

Using this approach, the NRC established three levels of significance for potential impacts—

SMALL, MODERATE, and LARGE—that provide a common framework for each of the resource 

areas assessed in NRC environmental evaluations, including this supplement. These 

significance levels provide a comparison tool that allows decisionmakers and interested parties 

to compare the relative significance of various environmental impacts. Each impact finding in 

the supplement is supported by substantial NRC staff analysis. Section 1.2.3 of the supplement 

also restates the definitions of the impact determinations. The terms SMALL, MODERATE, or 

LARGE are used in many NRC environmental review documents to draw attention to 

impact determinations. 

Although the NRC staff concluded in the SER that the repository would meet regulatory limits 

specified for safety, the purpose of DOE’s EISs and this supplement is to determine potential 

environmental impacts. In addition to concluding its constituent analyses with an impact 

determination (e.g., SMALL), the supplement provides specific concentration, dose, or other 
B–25 

appropriate impact information, where possible, associated with the particular resource 

evaluated in an analysis. Comments regarding impacts to tribes are further addressed in 

Sections B.2.4.4. and B.2.4.5. Comments about the use of existing data are further discussed 

in Section B.2.1.2.6, and comments about radiological and toxicological effects are further 

discussed in Section B.2.4.2. 

No changes were made to the supplement as a result of these comments. 

(019, 020, 046, 060, 116, 147-01, 147-12, 147-24) 

Miscellaneous 

B.2.1.2.27. COMMENT: One commenter quoted the supplement on page 1-4, Line 25, 

“(t)his supplement does not reflect a change to DOE’s proposed action or to DOE’s purpose of 

or need for the proposed action” and noted that the purpose and need of the proposed action, 

as described in DOE’s EIS, should be reiterated in the supplement to relay to readers the 

reason for the supplement. 

RESPONSE: The NRC staff acknowledges the request for a reiteration of DOE’s statements of 

purpose and need and proposed action. The proposed action is stated in Section 1.4 in the 

supplement. For completeness, the NRC staff has added a brief statement of DOE’s purpose 

and need within the same section of the document in response to this comment. 

(020) 

B.2.1.2.28. COMMENT: One commenter stated that a section of text in the draft supplement 

(Page 1-5 Lines 25-38), which describes the relationship of the supplement to DOE’s 

documents, is better suited for the introduction to the supplement because it is related to the 

purpose of the supplement. The commenter stated that the text after line 38 is more consistent 

with the title of the section, “Document Format.”

RESPONSE: The NRC staff agrees that additional clarity is needed in this section. The NRC 

staff has revised the title of Section 1.4 to “Document Purpose and Structure” to better reflect 

the content of that section. 

(020) 

Other Process Concerns 

B.2.1.2.29. COMMENT: Two commenters stated that the assumptions in the supplement 

should become binding license conditions because circumstances have changed since the 

documents were published. The commenters stated that a license would not be valid if new 

circumstances are not taken into account in the license application and the environmental 

analysis. As an example, a commenter expressed concern about the amount of high-burnup 

fuels being generated for disposal as different from what is presented in DOE’s license 

application. 

RESPONSE: The licensing process for a repository at Yucca Mountain has two major 

components, which inform the NRC’s regulatory decision: an environmental review and a safety 
B–26 

review. The NRC staff’s conclusions in the SER were based on its review of the license 

application submitted by DOE, including their proposed design and inventory of spent nuclear 

fuel and high-level waste to be disposed of in the repository. The analysis in the supplement 

also includes assumptions about the performance of the repository, including its inventory, 

which are consistent with the design and inventory in DOE’s Safety Analysis Report 

(supplement Section 1.2.2 and Sections B.2.2.2 and B.2.2.3 of this appendix). Changes to the 

information in DOE’s license application would require appropriate review by the NRC, including 

appropriate supplemental environmental review. 

In addition, the preparation of this supplement is one of several steps in the licensing process 

for the proposed repository. Information may be identified that requires further supplementation 

of DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. Comments concerning high-burnup fuels 

are specifically addressed in Sections B.2.1.2.29, B.2.2.2.1, B.2.2.3.1, B.2.2.3.2, and B.2.6.1.23. 

No changes were made to the supplement as a result of these comments. 

(146-01, 146-02) 

B.2.1.2.30. COMMENT: One commenter stated that the NRC’s rulemaking process is 

flawed, and that NRC should consider the analyses of those opposed to the Yucca Mountain 

project.

RESPONSE: The Yucca Mountain licensing decision is not a rulemaking, nor does the 

publication of this supplement represent a new rule or change to an existing rule. Rather, it 

documents an analysis of the potential impacts to groundwater and from surface discharges of 

groundwater beyond the postclosure compliance point for the proposed repository at 

Yucca Mountain. To develop this final supplement, the NRC staff has carefully considered the 

information and comments received on the draft supplement. The staff has reviewed, 

summarized, and responded to all comments, regardless of who submitted them and whether 

the comments agree or disagree with the NRC staff’s initial for final analyses or conclusions. 

To inform its decisionmaking processes, the NRC staff considers information from a variety of 

sources. Many of NRC’s licensing processes include opportunities for public comment. For this 

supplement, the NRC received over 1,200 comments from 5 transcribed public meetings and 

over 140 comment letters. The NRC’s rulemaking process also allows for public participation, 

and more information about public participation in the rulemaking process can be found on the 

NRC’s Web site at http://www.nrc.gov/about-nrc/regulatory/rulemaking/public-involvement.html. 

No changes were made to the supplement in response to this comment. 

(081) 

B.2.1.2.31. COMMENT: Commenters questioned whether or not the NRC had followed 

NRC Management Directive 3.17 (NRC Information Quality Program), which provides guidance 

to the staff for implementing OMB Information Quality Guidelines (FR 67 8460). In particular, 

the commenters stated that the supplement violates the IQA because the NRC did not conduct 

an independent peer review for the supplement, which is required for influential information 

under the IQA. 
B–27 

One of the commenters pointed to the NRC information guidelines in Management Directive 

3.17 for ensuring quality in “influential analyses” of risks to human health, safety, and the 

environment, as discussed in the OMB guidelines implementing the IQA (67 FR 8460). The 

commenter asked why the NRC’s guidelines in the Management Directive do not discuss quality 

principles in the Safe Drinking Water Act. 

RESPONSE: The NRC staff prepared this supplement in accordance with the IQA and NRC 

Management Directive (MD) 3.17, which implements the OMB Information Quality Guidelines. 

As discussed in MD 3.17, “[I]t is the policy of the U.S. Nuclear Regulatory Commission to 

ensure the quality of all information it relies on for making decisions or disseminates to the 

public. The NRC’s policies and practices are designed to ensure that the appropriate level of 

quality commensurate with the nature of the information is established and maintained.” 

The NRC’s Handbook for MD 3.17 provides guidance for staff in implementing MD 3.17 for 

information quality. The Handbook describes the methods the NRC applies to its information 

products to ensure quality and defines specific categories of information that may be suitable for 

peer review. The supplement does not fall within these categories. The Handbook (Table 1) 

also describes broad categories of NRC Information Products, their level of data quality review, 

and ways in which the public can request corrections. The supplement fits within “Licensing 

EISs and EAs” that are reviewed for data quality by “Branch/Division/Office Concurrence” and 

are subject to public comment as a way to request corrections. Each of these processes was 

followed in preparing the supplement. In keeping with the guidance in the Handbook, the NRC 

staff determined that a peer review of the information in the supplement was not appropriate or 

necessary to ensure information quality. 

No changes were made to the supplement as a result of these comments. 

(141, 146-06, 148) 

B.2.1.2.32. COMMENT: One commenter referred to NEPA and other laws, stating that the 

EPA Administrator is tasked with developing new approaches to biomedical studies, including 

new approaches to study complex mixtures, such as mixtures found in drinking water. The 

commenter questioned why, given these requirements, regulatory agencies have not conducted 

research on the interactions of metals that could be released from the repository and the 

potential health implications. 

RESPONSE: The U.S. Environmental Protection Agency (EPA) supports research related to 

chemicals and microbes in drinking water that may result in human health effects. In addition, 

the EPA, not the NRC, has regulatory authority concerning nonradiological metal contaminants 

in drinking water. Section 2.5 of the supplement discusses the applicability of EPA drinking 

water standards, and Section 3.1 includes discussions about nonradiological contaminants 

(metals) with regard to the EPA Oral Reference Dose and maximum contaminant levels. 

Related discussions about metal and radiological interactions can be found in Sections 

B.2.1.2.11, B.2.2.2.4, and B.2.2.2.5 of this appendix. 

No changes were made to the supplement as a result of these comments. 

(116) 
B–28 

B.2.1.2.33. COMMENT: A few commenters stated that the supplement does not adequately 

address the mitigation and remediation measures necessary to protect public health and safety 

and for consistency with NEPA. One commenter further noted the absence of an analysis of 

potential impacts from contaminants that may be released in the event of flooding of the 

repository site. Some commenters rejected DOE’s approach to defer mitigation and 

remediation planning until unusual conditions are detected in the groundwater. On this issue, 

one commenter stated that the environmental documents do not describe a monitoring plan 

capable of detecting such unusual conditions, while another commenter indicated that the NRC 

staff’s silence on this issue indicates concurrence with the DOE approach. These commenters 

also called for the inclusion of a groundwater well monitoring program and protocols for 

informing affected residents of potential contamination incidents. One commenter considered 

the DOE EIS insufficient because it does not address site reclamation if the repository 

project is shut down. A commenter also indicated in general that, per NRC regulations in 

10 CFR 51.109(c)(2), significant and substantial new information exists that should be 

analyzed in the supplement (see Section B.2.1.2.15 for responses to comments regarding 

new information). 

RESPONSE: The NRC staff acknowledges the concerns expressed by several commenters 

regarding mitigation and remediation measures for the proposed repository. However, 

comments about the exclusion of potential impacts due to specific events, such as the release 

of contaminants in the event of flooding of the repository site, are beyond the scope of the 

supplement, which concerns the potential impacts to groundwater and on surface discharges of 

groundwater beyond the postclosure compliance location, which is 18 km [11 mi] from the 

Yucca Mountain project site. The scope of this supplement is further described in the NRC’s 

Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 

2008a). DOE considered potential flooding events during operations and approaches for 

mitigating flood control structures in its license application (DOE, 2008b, Section 1.6.3.4.9). The 

NRC staff review of this analysis is in its SER (NRC, 2015a, Chapter 3, Section 3.2.1.1.3). 

The NRC staff’s ADR evaluated the best management practices and management actions that 

DOE proposed in its EISs for mitigation of potential adverse impacts and for protecting public 

health and safety (NRC, 2008a, Section 3.2.1.4.1). These measures included a commitment to 

implementing an environmental management system program to monitor the effectiveness of 

mitigation measures and modify them as necessary, developing a mitigation action plan to 

identify specific commitments, and chartering one or more mitigation advisory boards to be 

led by governmental entities in Nevada. The NRC staff concluded in the ADR 

(2008a, Section 3.2.1.4.1) that these efforts and commitments meet NRC regulations. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(124, 142, 149-17) 

B.2.1.2.34. COMMENT: One commenter stated that the supplement is insufficient because 

it does not consider in its analysis the intended expenditures in the Amargosa Valley vicinity for 

emergency preparedness facilities. The commenter stated that the monies had not been spent 

on these developments, such as hospitals and police and fire services. 
B–29 

RESPONSE: Comments regarding funding for facilities related to the proposed repository at 

Yucca Mountain, including emergency preparedness or response facilities, are beyond the 

scope of this supplement, which concerns an assessment of the potential impacts from 

repository releases to groundwater and from surface discharges of groundwater beyond the 

postclosure compliance location. The scope of the supplement is further described in the 

NRC staff’s ADR (NRC, 2008a) and in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029). Emergency facilities are addressed in the DOE 2008 EIS (DOE, 2008a; 

Section 4.1.11) and were not identified in the ADR as needing supplementation. 

No changes were made to the supplement as a result of this comment. 

(149-17) 

B.2.1.2.35. COMMENT: One commenter stated that the Yucca Mountain licensing process 

is insufficient for having not considered the Trans-Pacific Partnership (TPP) treaty and potential 

implications that the U.S. may eventually become host to other countries’ nuclear waste. 

RESPONSE: The NRC staff acknowledges the commenter’s concern about whether the TPP 

may result in acceptance of nuclear waste from other countries. However, comments regarding 

the waste inventory of the repository are beyond the scope of this supplement, which concerns 

an assessment of the potential impacts to groundwater and from surface discharges of 

groundwater beyond the postclosure compliance location. The waste inventory assumptions 

used in the supplement were based on information in DOE’s Safety Analysis Report 

(DOE, 2008b). In addition, DOE’s Safety Analysis Report addressed disposal of 70,000 MTU in 

a repository at Yucca Mountain. Disposal of a greater quantity is not part of DOE’s proposed 

action nor part of the licensing action under NRC consideration. The repository capacity of 

70,000 MTU is defined in the NWPA and changing the capacity would require a change in 

the law. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of this comment. 

(080-07) 

B.2.2 Supplement Assumptions 

B.2.2.1 Climate and Long Timeframes 

B.2.2.1.1. COMMENT: Commenters expressed concerns about the representation of 

future climates in the draft supplement, including a general concern about accuracy and 

uncertainty in projections of long-term future climates. One commenter suggested that climate 

may change in ways we cannot predict. Another commenter suggested that the full range of 

climates was not adequately represented by the use of “average climate” states in the draft 

supplement, including climates not found in past records as a result of human or natural effects. 

This commenter stated that there were significant deficiencies with regard to methodologies and 

assumptions associated with the climate scenarios evaluated in the supplement, referring to 

cases and regulations that address the requirements of NEPA. The commenter goes on to say 
B–30 

that NEPA requires analysis of the full range of climate conditions over the period studied, in 

this case one million years. The commenter contends that the range of conditions studied in the 

supplement is unlawfully truncated in that it assumes that physical conditions over the next 

million years will not resemble ones that existed in the area 26,000 years ago. 

One commenter, referring to page 2-16 of the draft supplement, asked if the representation of 

future climate in the draft supplement is consistent with the hotter and drier man-made climate 

changes assumed by other Federal agencies (e.g., the Bureau of Land Management and the 

U.S. Fish and Wildlife Service). Another commenter stated that the supplement appropriately 

addresses human-induced climate change. 

RESPONSE: Future climate change is treated differently in the supplement as compared with 

the TSPA. The TSPA incorporated a stochastic representation of four climates (DOE, 2008b, 

Section 2.3.1; NRC, 2014a, Section 2.2.1.3.5); present-day, monsoonal, glacial-transition, and 

full-glacial. As described in Sections 2.2.4 and 2.6 of the supplement, uncertainty in future 

climatic conditions is addressed by separately analyzing impacts for two climate states, one 

representing the hotter and drier present-day interglacial climate, and the other representing the 

cooler and wetter glacial-transition climate. The glacial-transition climate state resembles the 

climate 26,000 years ago when sections of the Amargosa River were likely perennial, and there 

was a paleo lake in Death Valley (Paces and Whelan, 2012). The supplement does not use an 

average climate over the 10,000-year or million-year periods, but rather, these two climate 

states reasonably capture the credible range of future conditions encompassing future 

climate change. 

Presently available information about human-induced climate change from the release of 

greenhouse gases indicates that for this region, the most potentially significant long-term effect 

is that the present-day interglacial climate (hot and dry) would persist longer than it would in the 

absence of human-induced change. The NRC staff considered the effect of anthropogenic 

(human-induced) climate change in the SER (NRC, 2014a; Section 2.2.1.3.5). In the 

supplement, consideration of a persistent present-day climate represents an extended, hotter 

and drier climate. 

The NRC staff’s consideration of an extended present-day hotter and drier climate is also 

consistent with the climate analyses of other Federal agencies. The NRC staff notes that other 

Federal agencies, such as the Bureau of Land Management and the U.S. Fish and Wildlife 

Service consider climate change over scales of one hundred to several hundreds of years 

(e.g., 200 years in BLM, 2012c). The NRC staff, however, considers climate change in the 

supplement over the next several millennia, and up to one million years. Projections of climate 

change caused by man-made greenhouse gases for repository performance (NRC, 2014a; 

Section 2.2.1.3.5) and for impacts in the supplement are also consistent with the U.S. Global 

Change Research Program and its 3rd National Climate Assessment (Melillo et al., 2014). 

No changes were made to the supplement in response to these comments. 

(046, 138, 146-11, 148) 

B.2.2.1.2. COMMENT: One commenter was concerned with projections of human activity 

and community characteristics under wetter conditions in the future. The commenter indicated 

the need to consider additional surface water storage during future humid conditions, as 

exhibited by a lake in Death Valley 10,000 years ago, leading to a denser and larger human 

population that could be affected at discharge locations throughout Southern Nevada. 
B–31 

RESPONSE: Projections of human activity, such as population shifts and associated changes 

in water use, are speculative. The NRC staff used the characteristics of the present-day 

population in the Town of Amargosa Valley to represent possible future populations that may be 

affected by releases from the repository, consistent with the description of the reasonably 

maximally exposed individual in 40 CFR 197.21 and 10 CFR 63.312. This approach is also 

consistent with recommendations of the National Academy of Sciences (NAS, 1995) on 

treatment of future populations for calculations over long time frames. 

The NRC staff, considering the characteristics of the present-day community in the Amargosa 

Farms area, analyzed impacts accounting for uncertainty in future changes to climate conditions 

and to pumping rates. In order to represent uncertainty in future water usage, the supplement 

considers two analysis cases for future pumping in Amargosa Farms (pumping and no pumping 

scenarios). In addition, the supplement considers possible future climate conditions that may 

affect impacts. As discussed in the supplement, these conditions and other conservative 

assumptions reasonably represent the uncertainty in potential environmental impacts over the 

one-million-year period. 

No changes were made to the supplement in response to these comments. 

(019) 

B.2.2.1.3. COMMENT: Several commenters questioned the feasibility of projecting 

geological, climatic, and hydrological conditions and evaluating impacts over long time periods, 

such as for 100-year, 10,000-year or one-million-year periods. In addition, two commenters 

pointed to the potential for changes in society and the unknown direction of human evolution 

over one million years, comparing the analysis timeframe to other milestones in human and 

societal evolution over the past several millennia. Two of these commenters suggested that 

impacts for these long timeframes should be indeterminate, uncertain, or a best guess. Another 

commenter suggested the one-million-year analysis period is beyond the scope of what is 

reasonably foreseeable under CEQ regulations. Citing the release from the Waste Isolation 

Pilot Plant as an example, one commenter additionally expressed concern that, based on the 

supplement’s conclusions, members of Congress may prematurely conclude that 

Yucca Mountain is an adequate repository site.

RESPONSE: The NRC staff acknowledges that changes will occur in the future to the 

populations, climate, hydrology, and geology of the Yucca Mountain region and, furthermore, 

that uncertainty in these changes leads to uncertainty in estimated impacts. The staff, however, 

does not agree that future projections and estimates of impacts are not feasible. The staff 

believes that useful information to aid in decisionmaking is provided by models covering long 

timeframes. A National Academy of Sciences (NAS) 1995 report evaluated this topic. The 

report, “Technical Bases for Yucca Mountain Standards,” provided guidance in the development 

of regulations for deep geologic disposal at Yucca Mountain. The NAS 1995 report concluded 

that scientifically justifiable analyses over many thousands of years in the future can be made. 

For the analyses at Yucca Mountain, the report recommended that dose be analyzed for the 

first 10,000 years and peak dose be analyzed after 10,000 years but within the period of 

geologic stability. 

The NRC staff selected the timeframes for the analysis in the supplement to be consistent with 

previous environmental assessments by DOE (2002, 2008a) and DOE’s TSPA analyses in its 
B–32 

Safety Analysis Report (DOE, 2008b). The NRC staff’s analysis of DOE’s license application 

can be found in the staff’s Safety Evaluation Report (NRC, 2010, 2014a,b; 2015a,b). 

With regard to commenter concerns with projecting changes to future human society and 

evolution, climate, and seismic and volcanic activity, issues relating to the performance of the 

repository and natural environment up to the compliance location are outside the scope of the 

supplement, which concerns an assessment of the potential impacts to groundwater and 

surfaces discharges of groundwater beyond the postclosure compliance location, which is 

18 km [11 mi] from the Yucca Mountain project site. The scope of this supplement is further 

described in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029), and in the 

NRC staff’s ADR (NRC, 2008a). As discussed in the supplement (Section 2.6), the NRC staff 

considers future changes to climate conditions and to pumping rates in the Amargosa Farms 

area. In order to represent uncertainty in future water usage, the supplement considers two 

analysis cases for future pumping in Amargosa Farms (pumping or no pumping scenarios). In 

addition, the supplement considers possible future climate conditions that may affect impacts. 

As discussed in the supplement, these conditions and other conservative assumptions 

reasonably represent the uncertainty in potential environmental impacts. 

The potential direct effects of seismic and volcanic activity on repository performance are 

considered in the supplement through the use of the contaminant releases calculated by DOE’s 

TSPA model, which includes such events. The supplement did not consider potential igneous 

or seismic events that may occur along the groundwater flow path beyond the postclosure 

compliance location. The specific locations, magnitudes, and changes to the affected 

environments would be speculative. While such events may themselves impact the 

environment, their occurrence is unlikely to significantly change the magnitude of the estimated 

impacts from contaminant releases because of the conservative assumptions made in the 

analyses, which are listed in Appendix A, Section A.3, including the assumption that the entire 

contaminant plume is discharged at each potential surface discharge location. 

The NRC staff acknowledges the commenters’ concerns with the proposed repository in light of 

recent releases at the WIPP facility during its operations. As previously noted, the supplement 

concerns the potential impacts of contaminants released from the repository to groundwater and 

surfaces discharges of groundwater beyond the postclosure compliance location. The NRC 

staff review of DOE’s safety analysis for the Yucca Mountain repository design, operations and 

postclosure performance is contained in Volumes 2 and 3 of the staff’s Safety Evaluation Report 

(NRC, 2014a, 2015a). 

The preparation of this supplement one of several steps in the licensing process for the 

proposed repository. The completion of licensing activities is subject to appropriations and 

other actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(018, 020, 080-06, 080-10, 082, 095-05, 095-08, 099, 146-15, 146-16, 147-16, 147-20, 147-24)

B.2.2.1.4. COMMENT: One commenter expressed concern, in light of long time frames 

involved, with the safety of nuclear waste in dry casks, the transportation of waste across the 

country, and the disposal of the waste. The commenter pointed to the importance of the NAS 
B–33 

 study on low-level radiation (since discontinued), because of the recent shutdown of the San 

Onofre Nuclear Generating Stations and the implied need for decommissioning and storage of 

the waste. 

RESPONSE: The NRC staff acknowledges the concerns expressed by the commenter about 

the safety of nuclear waste in dry casks, the transportation across the country, the discontinued 

National Academy of Sciences study on low-levels of radiation exposure, and disposal 

considering the shutdown and decommissioning of nuclear power plants. These comments are 

outside the scope of the supplement, which concerns an assessment of the potential impacts to 

groundwater and surfaces discharges of groundwater beyond the postclosure compliance 

location, which is 18 km (11 mi) from the Yucca Mountain project site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029), and in the NRC staff’s ADR (NRC, 2008a). 

No changes were made to the supplement in response to these comments. 

(080-15) 

B.2.2.1.5. COMMENT: Several commenters addressed the projections of groundwater 

pumping and water use in the Amargosa Farms area. Some commenters agreed with the 

supplement’s approach in projecting volume used but not projecting changes in society or the 

types of water use. One commenter stated that the NRC made a reasonable assumption in 

basing the volume of water pumped on historical records at Amargosa Farms. Other 

commenters expressed concern about water use types, speculating that water use would shift 

from dominantly agriculture to municipal and industrial in the future. 

Some commenters mentioned the supplement’s two analysis cases addressing the future 

pumping rates. The commenters stated the zero pumping analysis case is too conservative for 

calculating downstream impacts, and that using historical low levels of pumping instead would 

be a more reasonable reference. One of these commenters asked if likely future increases in 

groundwater pumping would be more or less conservative for Analysis Case #1. 

One commenter indicated the draft supplement does not clearly account for combined water 

withdrawals by the RMEI at the compliance location or through other wells near the compliance 

location. This commenter recommended that the NRC state in the final supplement whether the 

analysis assumes that withdrawals occur at and near the compliance location. 

Related to groundwater pumping and water use, some commenters speculated about future 

human population and activities in the area and their potential impacts. One commenter stated 

that the assumption that population and human activity near Yucca Mountain would remain 

unchanged most likely results in an underestimate of future harm. Another commenter argued it 

is unlikely that future society would lack the knowledge and technology to address potential 

contamination. This commenter suggested that the NRC was conservative in assuming that 

inhabitants would make extensive use of groundwater contaminated by releases from the 

repository. 

RESPONSE: As described in the supplement, the analysis makes several assumptions 

regarding future climate, withdrawals of water, and population along the groundwater flow paths 

from Yucca Mountain. To consider uncertainty in future climate, the supplement analyzed 

impacts under two different climates states; one hot and dry, similar to the present-day climate, 

and the other cooler and wetter, similar to past glacial or glacial-transition climates. This is 
B–34 

discussed in Section 2.2.4 of the supplement. These climate states are based on geologic 

evidence for past climate changes in the region, and are consistent with the climatic conditions 

incorporated into DOE’s analysis of repository performance. As discussed in the supplement in 

Section 2.2.4, the hot and dry climate also includes potential impacts for conditions that could 

occur from human-induced climate change. In conjunction with the two analysis cases for 

pumping in Amargosa Farms in Section 2.6 of the supplement, these climate states reasonably 

represent the conditions for consideration of future impacts. 

The two analysis cases were chosen to capture the range of impacts in the affected 

environment. As noted in the supplement in Section 3.1, for each case, impacts at the surface 

are considered by assuming that the entire contaminant plume was captured in the particular 

water source (e.g., by pumping at Amargosa Farms or by natural surface discharge at a 

particular discharge location). Assumptions regarding future pumping rates and water uses at 

Amargosa Farms (Analysis Case 1) are based on historical records over the past several 

decades, as described in Sections 2.2.3 and 2.4 of the supplement. This approach is consistent 

with the recommendations by the National Academy of Sciences (NAS, 1995) to avoid 

speculative projections caused by difficulties in projecting future societal behavior. In addition, a 

present-day constraint on pumping rates includes the State of Nevada Engineer’s order 

(Taylor, 2008) related to water levels in Devils Hole. Potential future changes to that order 

would also be speculative. 

One commenter suggested that the supplement does not clearly account for combined water 

withdrawals at the postclosure compliance location and Amargosa Farms area. In the 

supplement, the pumping rate is based on historical records from wells in the Amargosa Farms 

area. Potential withdrawals at the postclosure compliance location are a convention for 

calculation purposes and are not included in the supplement analysis cases. It should be noted 

that if the entire contaminant plume were to be captured by groundwater withdrawal at the 

postclosure compliance location (as conservatively considered in NRC regulations), no 

contaminants would flow to Amargosa Farms or further downstream. Conversely, the 

assumption of no pumping at the postclosure compliance location is conservative with regard 

to impacts at Amargosa Farms because the entire plume is assumed captured at 

Amargosa Farms. 

No changes were made to the supplement in response to these comments. 

(046, 137, 138, 142, 145, 148) 

B.2.2.2 Total System Performance Assessment and Other Modeling 

A number of commenters raised concerns that the NRC staff is relying on DOE’s TSPA, which 

was part of DOE’s license application for the proposed repository at Yucca Mountain as a 

primary input and as support for evaluating environmental impacts in this supplement. In 

particular, commenters made the following points: (i) uncertainties in models used in the TSPA, 

including the one-million-year assessment period, raise concerns regarding the credibility of the 

estimated impacts, and (ii) TSPA calculates a probability-weighted dose and not simply a 

dose consequence. 

The NRC staff’s use of the results of DOE’s TSPA as a primary input and as support for the 

analyses in the supplement is an appropriate means for evaluating environmental impacts. Use 

of the TSPA results is also an efficient and effective mechanism in that it uses existing 

information and minimizes the need for a duplicative analysis. 
B–35 

The TSPA is a model simulation that represents the performance of the repository system over 

time, including the potential releases from the repository to the environment and the potential 

effects on public health. The use of TSPA and other modeling assumptions is discussed in 

Section 1.2.2 and Appendix A of the supplement. The NRC staff’s evaluation of information 

used in the TSPA, as presented in DOE’s Safety Analysis Report, is given in the staff’s Safety 

Evaluation Report for the Yucca Mountain repository license application (NRC, 2014a). 

In its 2008 Supplemental EIS, DOE used mean results from the TSPA model to estimate the 

source term for radionuclides and transport to the postclosure compliance location. The 

supplement follows a similar approach, using the TSPA results as inputs to a transport model 

that calculates movement of the contaminants beyond the postclosure compliance location. 

The specific inputs are the mean amounts of radionuclides released from the repository over 

time, which are an intermediate result of the TSPA simulation. The mean TSPA release values 

are determined by averaging the behavior of the repository over the range of uncertainty and 

variability used to represent the features, events, and processes (e.g., corrosion of the waste 

package, seismic events, geologic and hydrologic characteristics of the site, and future climate 

conditions, among many other factors). The TSPA simulation uses scenario classes to 

represent unlikely events, such as large seismic events and igneous events, including events 

with a very low likelihood of occurrence (e.g., less than one chance in one million of occurring). 

Although DOE’s TSPA includes unlikely events associated with igneous disruption of the 

repository and large-magnitude seismic events, the TSPA also includes features, events, and 

processes that are expected to occur (e.g., corrosion of the waste package and seepage of 

water into the repository). Use of the TSPA results, therefore, provides a credible 

representation of the potential contaminant releases, which accounts for the environmental 

impacts that are reasonably likely to occur while also including impacts from events that are 

much less likely to occur. The use of TSPA results to estimate releases that could enter the 

aquifer from the repository does not underestimate the potential environmental impacts, 

because the TSPA accounts for releases due to unlikely events, regardless of the probabilities 

of these events. 

The NRC staff has revised text in Section 1.2.2 and in Appendix A, Section A.1.1 to further 

clarify the use of the results of DOE’s TSPA as a primary input and as support for evaluating 

environmental impacts in this supplement. 

Responses to specific comments concerning the TSPA or other aspects of performance 

assessment are provided below. 

B.2.2.2.1. COMMENT: Commenters expressed concern about the adequacy of DOE’s 

TSPA model as a basis for impact evaluations in the draft supplement, including concerns about 

model and data validity; the analyzed quantity of high-burnup fuel; and the impacts of 

phenomena at or near the repository, including mechanical, natural, and chemical processes, as 

well as natural hazards. Many of these commenters expressed concerns that the TSPA does 

not reflect current information or assumptions about the repository, the waste inventory, or the 

surrounding environment, and that some aspects, such as waste inventory and canister design, 

are unresolved. Commenters noted that if the source term used in the analysis at or near 

Yucca Mountain is incorrect, then conclusions based upon that source term, including the 

findings in the supplement, would likewise be incorrect. 

One commenter claimed that most of the State of Nevada’s contentions on the TSPA model 

were not addressed specifically in the NRC staff’s SER, nor have they been subjected to an 

opportunity for public comment, per NEPA and CEQ regulations. 
B–36 

RESPONSE: The NRC staff acknowledges the commenters’ concerns about how assumptions 

in the TSPA model may affect the conclusions in the supplement. Comments regarding the 

adequacy of DOE’s TSPA model are beyond the scope of this supplement, which concerns the 

potential impacts to groundwater and on surface discharges of groundwater beyond the 

postclosure compliance location. The scope of this supplement is further described in the 

NRC’s Notice of Intent to prepare the supplement (80 FR 13029), and in the NRC staff’s ADR 

(NRC, 2008a). 

The staff recognizes that the assumptions in the TSPA model affect the assessment in the 

supplement. DOE analyzed radiological impacts at the compliance location based on the 

results from the TSPA model submitted as part of its license application. In its safety 

evaluation, the NRC staff found that the TSPA model, methodology, and results were 

acceptable (NRC, 2014a). The NRC staff also found, in its ADR, that the TSPA results as 

reflected in DOE’s license application and EISs could be used as a source term for the 

postclosure compliance location (NRC, 2008a). Based on this finding, the supplement used the 

TSPA results for the mass flux of radionuclides reaching the compliance location as an input in 

the analysis of radionuclide transport to different locations along the flow path beyond the 

postclosure compliance location. 

Although the adjudication is currently suspended, participants in the adjudication may continue 

to pursue these contentions before the Atomic Safety and Licensing Board or raise new issues 

in the form of new or amended contentions, upon resumption of the adjudication. Information 

may be identified that requires further supplementation of DOE’s 2002 and 2008 EISs in the 

future. The completion of licensing activities is subject to appropriations and other actions 

external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(001, 006, 061, 080-10, 080-16, 102, 104, 108, 115, 116, 121, 129, 133, 134, 138, 141, 146-02, 

146-06, 148) 

B.2.2.2.2. COMMENT: A few commenters expressed concern about models used in the 

draft supplement and the general process for calculating impacts. One commenter stated that 

the draft supplement used an unproven EPA radiation groundwater model. One commenter 

cited the example of the groundwater model for the test site (NNSS) not being validated until 

2030, and wondered how the groundwater model used in the draft supplement could reproduce 

groundwater conditions, particularly considering extreme conditions and future climate 

uncertainty. Another commenter asked how the models were validated and if current parameter 

values were used in the validation. One commenter stated that the scenarios used in the draft 

supplement are not realistic. Another commenter wanted confirmation that the NRC staff used 

DOE’s analysis for releases up to the compliance location, and then used NRC staff analyses in 

the draft supplement to evaluate contaminant transport to downstream locations. 

RESPONSE: The commenters are correct that the NRC staff analysis in the supplement is 

generally derived from DOE’s calculated releases from the repository and transport to the 

postclosure compliance location. DOE’s analysis of radiological impacts at the postclosure 

compliance location, as presented in its EIS (DOE, 2008a), is based on groundwater flow and 

transport simulations included in its TSPA model as part of its license application. DOE’s 

saturated zone flow and transport model is discussed in its safety analysis (DOE, 2008b; 

Section 2.3.9). The NRC staff review of this analysis is given in the staff’s Safety Evaluation 

Report (NRC, 2014a; Chapters 11 and 12, Sections 2.2.1.3.8 and 2.2.1.3.9). 
B–37 

In its ADR, the NRC staff determined that it could adopt the approach DOE used in estimating 

releases from the repository and the impacts at the postclosure compliance location, but that the 

analysis needed to be supplemented to consider impacts on groundwater beyond that location. 

As discussed in the supplement (Sections 2.1, 3.1, and Appendix A), the NRC staff used the 

well-established Death Valley Regional Flow System (DVRFS) model to help define the affected 

environment and analyze the impacts on groundwater under different potential future climate 

and water use conditions. The DVRFS model has been calibrated and shown to provide a good 

fit to measured hydrologic conditions (Belcher and Sweetkind, 2010). The analysis cases in the 

supplement included both substantial and limited pumping of groundwater for irrigation 

purposes at Amargosa Farms under both wet and dry climate states. Modeling this combination 

of cases enabled the NRC staff to evaluate how the rate of pumping and volume of groundwater 

withdrawal could affect radionuclide concentrations in the groundwater and at the locations of 

potential surface discharge beyond the compliance location under a range of future conditions. 

No changes were made to the supplement as a result of these comments. 

(116, 146, 147-03, 147-12, 147-28, 148, 149-01, 149-15) 

B.2.2.2.3. COMMENT: Two commenters commented on the model that accounts for 

recycling of contaminants that are pumped from the aquifer and recharged back to the aquifer 

via irrigation used to assess impacts in the Amargosa Farms area. One commenter stated that 

there is an inconsistency between descriptions in Chapter 3 and Appendix A of the draft 

supplement regarding water uses, exposure pathways, and contaminant recapture fractions. 

This commenter provided a detailed discussion and asked the NRC to clarify this inconsistency 

in the final supplement. The other commenter suggested that the recycling analysis needs to be 

reasonable without being overly complex. The commenter suggested that the supplement’s 

assumption of 100% groundwater capture at Amargosa Farms may be reasonable for any 

particular year but is unreasonably conservative when applied to longer time periods. The 

commenter further expressed disagreement with the use of the recycling model for estimating 

impacts at the postclosure compliance location. The commenter also questioned how the 

draft supplement can assume that salts can migrate through soil via excess irrigation water 

(as discussed in Appendix A, pages A-12 and A-13) and either be recaptured by pumping or 

migrate downstream, while also assuming that contaminants from the repository are not 

similarly flushed but rather are retained in the soil and recaptured by pumping. 

RESPONSE: The NRC staff’s methodology for calculating the concentration of contaminants in 

water withdrawn from wells at Amargosa Farms is described in Section A.2.1 of the supplement. 

The method uses recycling and recapture factors along with the contaminant mass arriving at 

Amargosa Farms and volume of water withdrawn. DOE used a similar calculation in its 

irrigation recycling model for water withdrawal at the postclosure compliance location in its 

TSPA analyses (SNL, 2007b). The NRC staff’s review of DOE’s analysis can be found in the 

SER (NRC, 2014a, Section 2.2.1.2.1). As discussed in Appendix A, Section A.2.1, a 

simplification of the irrigation recycling model is used for analyzing impacts in the Amargosa 

Farms area. For the supplement analysis, the recapture factor is conservatively set to 1 as a 

simplifying assumption. This value means that all irrigation water that flows back in to 

(recharges) the aquifer is captured by a well in the Amargosa Farms area. This assumption is 

conservative in that all of the contaminants reaching Amargosa Farms contribute to calculated 

impacts. For the recycling factor, the fraction of groundwater withdrawal used for irrigation is set 

as 0.86, based on analysis of water use in Amargosa Farms (Moreo and Justet, 2008). For the 

analysis in the supplement, irrigation is considered to be the only water use that leads to 

overwatering, and thus the potential to recycle contaminants. 
B–38 

The schematic shown in supplement Figure A-2 (Water Uses and Exposure Pathways 

Biosphere Conceptual Model) does not include the irrigation recycling model. The analysis in 

the supplement uses the recycling and recapture factors associated with irrigation to calculate 

radionuclide concentration in well water, which is an input to the exposure pathway and dose 

model in Figure A-2. Thus, the analysis separates the calculation of irrigation effects on 

contaminant concentration from calculations for the exposure pathway and dose. The recycling 

and recapture factors of the irrigation recycling model are described in Appendix A, Section 

A.2.1, “Groundwater Pumping, Recycling, and Irrigation.” The exposure pathways shown in 

Figure A-2 are described in Section A.2.3, “Biosphere Exposure and Dose Conversion.” 

The NRC staff agrees that the assumptions in the irrigation recycling model are conservative. 

The NRC staff notes, however, that conservative assumptions are reasonable where they allow 

for simplified models to be used for difficult-to-estimate input values where the impacts are 

nevertheless small. 

In response to these comments, the NRC staff revised text in Section 3.1.1 of the supplement to 

clarify the distinction between recycling and recapture estimates for the postclosure compliance 

location and for the Amargosa Farms area. Also, Section A.2.3 in the supplement has been 

revised to emphasize the relationship between the irrigation recycling model and the exposure 

pathway schematic in Figure A-2. 

(137, 138) 

B.2.2.2.4. COMMENT: A commenter expressed concerns about the representation of 

chemical processes or approaches used for the analyses in the draft supplement or as used in 

DOE’s modeling for the license application. The commenter stated that sorption properties of 

individual radionuclides are not known, nor are competitive sorption properties known when two 

or more radionuclides or heavy metals are present. The commenter stated that research is 

needed, such as additional large-scale testing. 

The commenter also (i) expressed concern with unknown health hazards associated with 

mixtures of chemicals and radionuclides, (ii) stated that risks from canister corrosion is not 

resolved and asked why chloride and nitrate are included in the analysis, but sulfate is not, and 

(iii) asked why chromium is not mentioned for impacts in the Amargosa Farms area in the draft 

supplement, especially since there is so much chromium in the repository. 

RESPONSE: The NRC staff acknowledges the commenter’s concerns. Those comments that 

pertain specifically to the release rates of radionuclides from the repository, including the 

sorption of individual radionuclides near the repository and competitive sorption effects, are 

outside of the scope of this supplement, which concerns an assessment of the potential impacts 

to groundwater and surface discharges of groundwater beyond the postclosure compliance 

location, which is 18 km [11 miles] from the Yucca Mountain project site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The commenter expressed concern with the treatment of chromium in the supplement. The 

rationale for excluding chromium from the analysis of impacts is discussed in Appendix A, 

Section A.1.1. In its 2002 EIS (DOE, 2002), DOE estimated the impact of chromium by 

conservatively assuming the presence of the fully oxidized state, chromium(VI) (chromium in a 

valence state of +6). In its 2008 EIS (DOE, 2008a; Sections 5.1.2 and F.5.1), DOE determined 

that chromium(III) would be the predominant chromium species present in the groundwater. If 
B–39 

chromium(VI) formed from corrosion of stainless steel and Alloy 22, DOE found that it would be 

efficiently and quickly reduced to chromium(III) in the expected repository environment. 

Chromium(III) is not toxic to humans. This chemical species readily sorbs onto solid surfaces 

and would not be mobile in the groundwater in the affected environment. 

The commenter also expressed concern about the analysis in the supplement of impacts to the 

affected environment beyond the postclosure compliance location. These comments concern 

the sorption properties of radionuclides and nonradioactive metals in the saturated zone, health 

effects when multiple types of contaminants are present, and the behavior of chromium 

released from the repository. The sorption properties and dose conversion factors used in the 

NRC staff analysis are discussed in Appendix A, Section A.1.2. As stated in the supplement, 

these values are drawn from the DOE Safety Analysis Report (DOE, 2008b, Section 2.3.9), with 

subsequent updates based on further literature values (DOE, 2014a). The low concentrations 

of contaminants calculated in the groundwater indicate that any potential competitive sorption 

effects are not significant. The NRC staff is not aware of any new information on sorption 

properties of radionuclides, competitive sorption effects, or health effects when both 

radionuclides and nonradionuclide metals are present. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s EISs in the future. 

No changes were made to the supplement as a result of these comments. 

(116, 147-12) 

B.2.2.2.5. COMMENT: A commenter expressed concern with the uncertainty and health 

risks posed by the release of a large amount of metals from the repository as a result of 

corrosion of those materials in the repository. The commenter mentioned several mechanisms 

or particular environmental conditions that they believe have been neglected and cited studies 

that support higher corrosion rates than those used in the performance assessment. 

RESPONSE: The commenter raised concerns related to the NRC staff’s use of information 

from the DOE’s TSPA, which was part of DOE’s license application for the proposed repository 

at Yucca Mountain, as a primary input and as support for evaluating environmental impacts in 

this supplemental EIS. A discussion of the use of modeling in the supplement can be found in 

Section 1.2.2, Appendix A, and Appendix B, Section B.2.2.2. The NRC staff’s evaluation of 

information on these topics, as presented in the license application, is contained in the staff’s 

Safety Evaluation Report for the Yucca Mountain repository license application (e.g., NRC, 

2014a). In addition, several of the issues raised by commenters are the subject of contentions 

pending in the suspended adjudicatory proceeding. 

As part of its license application, DOE conducted a performance assessment that identified and 

examined the effects of various features, events, and processes on the performance of the 

repository. The performance assessment included accounting for uncertainties in metal 

corrosion processes and rates that may affect the performance of the engineered barrier 

system. These uncertainties were analyzed by multiple simulations in the TSPA model using 

different corrosion rate input parameters (DOE, 2008b, Section 2.3.6). The NRC staff’s review 

of this analysis is in its Safety Evaluation Report (NRC, 2014a; Chapter 4, Section 2.2.1.3.1). 

As explained in Section A.1.1 of the supplement, the analysis of impacts from nonradiological 

contaminants used release and transport rates based on the corrosion rates of the engineered 
B–40 

barrier components in the repository used in the TSPA. As discussed in the supplement, the 

release rates used are conservative in that they include all the potentially exposed surface area 

of the engineered barrier systems in the repository as subject to corrosion. 

No changes were made to the supplement as a result of these comments. 

(116)

B.2.2.2.6. COMMENT: One commenter stated that accumulation of uranium-bearing 

minerals could occur near the repository and along the groundwater pathway wherever 

evaporation occurs. The commenter stated that the likelihood of accumulation is increased by 

the presence of vanadium and suggested several sources of vanadium in the natural 

environment (e.g., basaltic rock, reducing environments of swamp or marsh deposits) and in the 

materials used in repository construction. The commenter stated that the range of moisture 

conditions in the repository that may affect accumulation of radionuclide-bearing minerals 

should be expanded to include saturated conditions, such as perched water and intermittent 

flooding of the repository during wetter climates. The commenter stated that an analysis of the 

risk of criticality is needed for the possible accumulations of radionuclide-bearing minerals at 

locations in or downgradient of the repository. 

The commenter suggested deposits of uranium-vanadium-bearing minerals at Yeelirrie 

(Western Australia) and elsewhere, including southern Nevada, point to evaporation as an 

accumulation mechanism for uranium at the land surface. The commenter stated that the draft 

supplement should have considered radionuclides removed from the groundwater and 

deposited by sequential precipitation of minerals during evaporation or electrochemical 

reduction. The commenter suggested that accumulation of uranium-bearing minerals at 

groundwater discharge areas would result in ingestion, inhalation, and external exposure 

pathways that were not evaluated in the draft supplement. 

RESPONSE: The aspects of these comments that pertain directly to the performance of the 

repository are out of the scope of this supplement. These aspects include criticality and 

uranium accumulation in or near the repository up to the postclosure compliance location. The 

scope of this supplement concerns an assessment of the potential impacts to groundwater and 

surface discharges of groundwater beyond the postclosure compliance location, which is 11 mi 

[18km] downstream along the flow path from the Yucca Mountain site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

With respect to the comments concerning the potential for criticality and for health effects due to 

accumulation of carnotite or other uranium minerals beyond the compliance location, DOE 

considered the possibility of criticality of released fissionable material in the repository in its 

safety analysis and concluded that it could be excluded from analysis on the basis of very low 

probability (DOE, 2008b, Section 2.2.1). The NRC staff review of this analysis is given in its 

Safety Evaluation Report (NRC, 2014a, Chapter 2, Section 2.2.1.2.1). For similar reasons, the 

accumulation of sufficient U235 or other fissionable material in a configuration that facilitates 

criticality in deposited minerals along the groundwater pathway in Amargosa Desert or at 

groundwater discharge sites is also highly unlikely because the uranium released from 

commercial spent nuclear fuel is likely to be less than 1% U235, and the chemical and physical 

conditions required for criticality are unlikely to form at these locations. 
B–41 

One commenter pointed to surficial uranium deposits in arid environments such as the Yeelirrie 

Deposit in Australia (e.g., IAEA, 1984) or those in the western United States as possible 

analogs to potential accumulations of repository contaminants in the aquifer or on the surface in 

the affected environment. The Yeelirrie Deposit was formed by periodic wetting and 

evaporation in an arid climate that led to the accumulation of a carnotite-bearing caliche 

(also called calcrete or hardpan) in soils at or near the ground surface. A similar environment 

and potential exposure pathway is described in the supplement in Appendix A, Section A.2.3, 

subsection titled Environment 3: Surface Discharge at Wet Playas. The primary exposure 

pathways for such a deposit are dust inhalation, ingestion, and external (skin) contact. As 

discussed in the supplement in Section 3.1.2.1 and Appendix A, Section A.2.2, the NRC staff 

analysis is conservative in its evaluation of the potential accumulation of contaminants at 

surface discharge sites. The evaporite soil model in the supplement assumes complete 

evaporation of discharged groundwater, forming evaporite minerals that concentrate 

contaminants. This approach makes no assumptions about the formation of specific minerals. 

Given the relatively low calculated contaminant concentrations in the evaporite soils, as detailed 

in Table 3-6 in the supplement, formation of significant amounts of uranium-vanadium mineral 

phases like those characteristic of the Yeelirrie Deposit is very unlikely. Formation of trace 

amounts of uranium-vanadium minerals within the soil would not lead to impacts greater than 

those evaluated in the supplement. 

The commenter also suggested that accumulation of uranium and other contaminants could 

occur in reducing environments such as the “black mats” of organic-rich paludal (marsh) 

deposits. Paludal deposits may have formed within the alluvial sequence of Amargosa Desert 

under past wetter climatic conditions and may form at future spring and marsh environments 

such as those projected in the supplement for the State Line/Franklin Well area. Buried, 

isolated, sparse occurrences of thin layers with reducing conditions have been observed in 

boreholes in Amargosa Desert as well. 

But the accumulation of radionuclide-bearing minerals at buried locations along the flow path 

would reduce the flux of radionuclides reaching a downstream receptor. In the supplement, the 

NRC staff analysis conservatively does not consider the possibility that some radionuclides 

would not reach an affected environment due to mineral accumulation along the groundwater 

pathway. Potential accumulation of contaminants in marsh deposits at surface discharge 

locations is discussed in the supplement in Sections 2.3.4 and 3.1.2.1. Calculated 

accumulations of contaminants in a marsh environment are evaluated and found to be very low 

(Table 3-6; Salt Marsh Soil Mode), as are the associated potential health effects (Table 3-7). 

No changes were made to the supplement as a result of these comments. 

(148) 

B.2.2.2.7. COMMENT: One commenter noted that assumptions in the draft supplement are 

overly conservative and result in an overestimation of potential impacts. This commenter further 

stated that groundwater flow inputs for the draft supplement that were derived from the TSPA 

are also conservative. 

RESPONSE: The NRC staff agrees that DOE’s impact analysis at the postclosure compliance 

location was based on results obtained from its performance assessment model, which included 

several conservative assumptions about features, events, and processes. Similarly, the 

analysis in the supplement makes several conservative assumptions to support the modeling 

and evaluation of potential impacts to groundwater and surface discharges beyond the 
B–42 

postclosure compliance location. The inclusion of conservative assumptions in these impact 

evaluations are a means for addressing uncertainties in the geologic setting for groundwater 

flow and radionuclide transport. Accordingly, conservative assumptions are used in the 

supplement to account for uncertainties in the groundwater model inputs. 

No changes were made to the supplement as a result of this comment. 

(138)

B.2.2.2.8. COMMENT: One commenter stated that the impacts presented in the draft 

supplement represent risk rather than potential actual dose for a future scenario. The 

commenter noted that TSPA results used as input in the draft supplement do not represent dose 

consequences of events, were they to actually occur, but rather, they represent a dose weighted 

by the probability of the event occurrences (e.g., igneous intrusion into the repository). The 

commenter requested that the supplement present both consequence (dose) and probability of 

occurrence for the full range of scenarios and uncertainty. 

RESPONSE: As discussed in the NRC staff’s ADR (NRC, 2008a) and in the supplement in 

Section 1.2.1, the NRC staff accepted the DOE analysis of releases from the repository, as 

calculated by DOE using their TSPA. The TSPA uses probabilistic methods to assess the 

performance of the repository and to estimate the doses that could result from releases from the 

repository following permanent closure. The NRC staff review of DOE’s performance 

assessment is in its SER (NRC, 2014a). The NRC staff used results from DOE’s TSPA on 

repository releases as representative of the likely types and levels of contaminants that could 

enter the groundwater system and be transported beyond the postclosure compliance location. 

As discussed in the supplement, the staff analysis used these results, along with conservative 

models and assumptions, to calculate potential impacts to the affected environment beyond the 

postclosure compliance location. This approach provides a reasonable means of quantifying 

potential impacts and is consistent with NRC regulations (10 CFR Part 51) and guidance 

(e.g., NRC, 2003) for analysis of environmental impacts. Additional information about the NRC 

staff’s use of TSPA in the supplement can be found in Appendix A and Appendix B, 

Section B.2.2.2. 

No changes were made to the supplement as a result of these comments. 

(148)

B.2.2.2.9. COMMENT: A commenter stated that the draft supplement relies too heavily on 

models used by DOE in its license application and, thus, does not address uncertainty and 

variability within and among the scenario classes. The commenter also stated that the 

supplement uses inappropriate data sets and statistical methods that have been challenged in 

contentions to the license application, such that uncertainties in radionuclide transport and 

radiological impacts are substantially underestimated in the supplement. 

RESPONSE: As discussed in the NRC staff’s ADR (NRC, 2008a) and in the supplement in 

Section 1.2.1, the NRC staff accepted the DOE analysis of releases from repository, as 

calculated by DOE using its TSPA. The NRC staff review of DOE’s performance assessment is 

in its Safety Evaluation Report (NRC, 2014a). The NRC staff used results from DOE’s TSPA for 

repository releases as representative of the likely types and levels of contaminants that could 

enter the groundwater system and be transported beyond the postclosure compliance location. 

The supplement also used methods and parameters similar to those in the DOE models to 
B–43 

calculate potential health impacts at different locations under the different conditions described 

in the supplement. Specific challenges to the models and parameters used by DOE in its 

license application are pending in the adjudicatory proceeding, which is currently suspended. 

As discussed in the supplement in Section 2.6, the NRC staff’s analysis considered two analysis 

cases under different future climate conditions to provide a reasonable range of conditions to 

assess the affected environment and potential impacts. Uncertainties are addressed in the 

analysis through the use of the multiple conditions and conservatisms in the models and 

assumptions, as discussed in the supplement. The preparation of this supplement is one of 

several steps in the licensing process for the proposed repository. Information may be identified 

through the proceeding or otherwise that requires further supplementation of DOE’s EISs in the 

future. The completion of licensing activities is subject to appropriations and other actions 

external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(148) 

B.2.2.2.10. COMMENT: Two commenters stated that criteria and rules for Yucca Mountain 

have changed over time, including those pertaining to groundwater travel times, point of 

compliance, dose levels, and the compliance period. One of the commenters stated that the 

rules and criteria changed because the earlier criteria would have been exceeded and would 

disqualify Yucca Mountain from further consideration as the site for a repository. The other 

commenter further stated that the supplement’s evaluation ignores the populations most in need 

of protection from radioactivity, women and children. 

RESPONSE: The NRC staff acknowledges the commenters’ concern about the requirements 

applicable to the proposed repository at Yucca Mountain. These comments are outside the 

scope of the supplement, which concerns an assessment of the potential impacts to 

groundwater and surfaces discharges of groundwater beyond the postclosure compliance 

location, which is 11 miles [18 km] from the Yucca Mountain project site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The requirements that the NRC staff used for its evaluation in its Safety Evaluation Report are 

contained in the NRC regulation for Yucca Mountain (10 CFR 63), which under the NWPA, must 

be consistent with EPA’s standards for Yucca Mountain (40 CFR 197). Both of these 

regulations were issued as proposed rules and finalized following consideration of public 

comments. The responses to public comments on 10 CFR Part 63 specifically addressed how 

the postclosure dose limit was protective of potentially more radiosensitive populations, such as 

children (66 FR 55732). 

No changes were made to the supplement as a result of these comments. 

(146-01, 147-23) 

B.2.2.3 Repository Inventory, TADs, Drip Shields 

B.2.2.3.1. COMMENT: Commenters stated that many of the assumptions in the NRC 

staff’s supplement and in DOE’s EISs are no longer valid because they are based on 

assumptions in the license application DOE submitted to the NRC in 2008 that do not reflect the 
B–44 

current state of affairs. Some commenters expressed concern that the proposed repository 

could not even hold the current inventory of spent commercial fuel, and that the supplement is 

incorrect to conclude that additional disposal beyond 70,000 MTU is not reasonably 

foreseeable. One commenter stated that DOE evaluated a larger repository (i.e., greater than 

70,000 MTU) in its EIS, and the NRC should include, at a minimum, a qualitative discussion of 

possible impacts from an expanded repository in the final supplement. Other commenters 

pointed to the authorization by the President of the United States in 2015 for DOE to develop a 

repository for defense waste only, which would have the effect of removing defense waste from 

the Yucca Mountain repository, contrary to DOE’s license application, which included both 

defense wastes and commercial wastes. Commenters also asserted that changes in thermal 

characteristics of the inventory due to changes in the inventory (e.g., no defense wastes, 

disposal of more high-burnup fuel, disposal of more 70,000 MTU at Yucca Mountain, changes to 

the storage canister characteristics) could affect repository performance and design and require 

new analyses to be performed for the supplement and the license application. One commenter 

asserted that because of this difference with respect to defense wastes, the application and 

associated environmental evaluations, including the supplement, violate the NWPA. One 

commenter stated that there is no inadequacy related to waste inventory in DOE’s EIS for 

Yucca Mountain because DOE evaluated a representative quantity of SNF and HLW in its 

proposed action and evaluated much greater quantities of SNF and HLW that could exist in the 

future in its cumulative impacts evaluation. 

RESPONSE: Comments regarding changes to the proposed repository’s waste inventory are 

outside the scope of this supplement, are outside the scope of the supplement, which concerns 

an assessment of the potential impacts to groundwater and surfaces discharges of groundwater 

beyond the postclosure compliance location, which is 11 miles [18 km] from the Yucca Mountain 

project site. The scope of this supplement is further described in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The disposal of commercial SNF and defense HLW in separate repositories would change 

assumptions in the license application, and in DOE’s EISs. If DOE changes its license 

application, the NRC staff would reevaluate the inventory assumptions in the process of 

updating its reviews. Regarding the potential disposal of more than 70,000 MTU at Yucca 

Mountain, DOE did not account for additional disposal in its license application; thus, this is 

neither part of DOE’s proposed action nor part of the NRC’s potential licensing action. Any 

proposal to dispose of more than the 70,000 MTU at a Yucca Mountain repository is contrary to 

the NWPA and would require a change in the law. This option is not reasonably foreseeable at 

this time. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the EIS supplement as a result of these comments. 

(001, 006, 018, 019, 042, 046, 080-06, 080-10, 102, 104, 117, 118, 128, 129, 133, 134, 138, 

141, 146-01, 146-02, 146-06, 146-07, 146-14, 147-23, 147-24, 148) 

B.2.2.3.2. COMMENT: Commenters expressed concern that because the NRC has 

authorized many power plant licensees to burn fuel longer, the fuel that would go to Yucca 
B–45 

Mountain does not match what DOE and the NRC staff evaluated in the application, TSPA, and 

associated environmental evaluations. Commenters stated that high-burnup spent fuel has 

higher thermal output and can increase degradation of the fuel cladding (e.g., through 

embrittlement), making the spent fuel more susceptible to damage during transportation and 

disposal. Additionally, commenters noted that longer storage times for spent nuclear fuel 

containing high-burnup fuel may require repackaging and separate containers for spent fuel 

assemblies. Commenters recommended that the supplement include analyses that evaluate 

the impacts of increasing amounts of high-burnup fuel. One commenter asked how much 

high-burnup fuel is planned for the repository. 

RESPONSE: Comments regarding changes to the amount of high-burnup spent fuel included 

in the proposed repository’s waste inventory are not within the scope of this supplement, which 

concerns an assessment of the potential impacts to groundwater and surface discharges of 

groundwater beyond the postclosure compliance location from the inventory proposed in DOE’s 

license application. The scope of this supplement is further described in the NRC’s Notice of 

Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The waste inventory assumptions used in the supplement are based on information in DOE’s 

license application. This inventory is also accounted for in DOE’s EISs, which the staff 

determined to be adequate for adoption with further supplementation, as reflected in the ADR. 

In particular, DOE acknowledged in its license application that there was uncertainty in the 

actual amount of high-burnup fuel that would be shipped to the proposed repository, depending 

on whether the oldest or youngest fuel was shipped first. Thus, DOE accounted for differing 

amounts of high-burnup fuel by considering an average burnup ranging from 36 GWd/MTHM 

(gigawatt days per metric ton of heavy metal) if the oldest fuel is shipped first, to 49 GWd/MTHM 

if the youngest fuel is shipped first (DOE, 2008b, page 2.3.7-21). Additionally, DOE presented 

information in its license application supporting a range of burnups from 15 to 65 GWd/MTHM 

considered in modeling the degradation of spent fuel (DOE, 2008b, Rev. 1, page 2.3.7-41). 

DOE’s application includes a wet handling facility and its capabilities to receive, handle, and 

repackage failed spent nuclear fuel (DOE, 2008b; Section 1.2.5). If DOE updates its license 

application, the NRC staff would review the new information and update its reviews, as 

appropriate. 

No changes were made to the supplement as a result of these comments. 

(016, 062, 071, 072, 080-10, 080-16, 098, 108, 128, 133, 134, 146-01, 146-09, 146-16) 

B.2.2.3.3. COMMENT: Several commenters stated that the NRC staff’s draft supplement, 

the technical basis for the repository performance assessment, and the DOE environmental 

impact statements are out of date and based on incorrect assumptions. These comments were 

attributed to DOE terminating work on the transport, aging, and disposal (TAD) canister concept 

prior to completing a design that would meet the NRC’s performance requirements. The 

commenters also noted that the TAD concept is relied upon in DOE’s application, including its 

EISs. Related to the lack of a TAD design, commenters stated that DOE assumptions about 

canister fuel capacity, number of canisters, canister performance, drip shield installation and 

performance, and other assumptions are likewise incorrect. 

RESPONSE: The NRC acknowledges the concerns expressed in these comments regarding 

the state of work on the concept and design of TAD canisters for use in the proposed geologic 
B–46 

repository and the use of information from DOE’s TSPA to support impact evaluations in the 

supplement. However, these comments are outside the scope of the supplement, which 

concerns an assessment of the potential impacts to groundwater and surface discharges of 

groundwater beyond the postclosure compliance location, which is 18 km [11 mi] from the 

Yucca Mountain project site. The scope of this supplement is further described in the NRC’s 

Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). 

The NRC staff’s use of information from the DOE’s TSPA, which was part of DOE’s license 

application for the proposed repository at Yucca Mountain, as a primary input and as support for 

evaluating environmental impacts in this supplemental EIS is discussed in Section 1.2.2 and 

Appendix A of the supplement. The NRC staff’s evaluation of TSPA as presented in the license 

application, including the specific issues identified by commenters, is contained in the staff’s 

Safety Evaluation Report for the repository license application (NRC, 2014a, Section 2.2.1.3.1). 

In addition, several of the issues raised by commenters are the subject of contentions pending 

in the suspended adjudicatory proceeding. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(006, 062, 080-10, 080-08, 117, 118, 129, 133, 134, 141, 146-01, 146-06, 146-07, 147-06, 

147-23, 148) 

B.2.2.3.4. COMMENT: Several commenters expressed concerns regarding the draft 

supplement’s reliance on the assumption that titanium drip shields would be used in the 

repository. Some commenters questioned whether taxpayer dollars would be appropriated to 

fund installation of the drip shields and remarked that the drip shields may never be installed. 

Others questioned the design of the drip shields, the role of the drip shields in the engineered 

barrier system, and whether the technology would be available to install the drip shields 

correctly 100 years after repository closure. Some commenters also noted that the proposed 

canisters and other aspects of the DOE’s analyses relied on by NRC in the supplement are 

obsolete assumptions. 

RESPONSE: The NRC staff acknowledges the concerns expressed in these comments 

regarding the use of titanium drip shields, including the future appropriation of funds for their 

installation in the proposed geologic repository. However, these comments are outside the 

scope of the supplement, which concerns an assessment of the potential impacts to 

groundwater and surface discharges of groundwater beyond the postclosure compliance 

location, which is 18 km [11 mi] from the Yucca Mountain project site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029), and in the NRC staff’s ADR (NRC, 2008a). 

A number of commenters raised concerns related to the design and future installation of the drip 

shields and the NRC staff’s use of results from DOE’s performance assessment to support 

evaluation of environmental impacts in this supplemental EIS. The NRC staff’s evaluation of 

information on these topics, as presented in the license application, is contained in the staff’s 

Safety Evaluation Report for the Yucca Mountain repository license application (NRC, 2015a; 
B–47 

Chapters 2 and 4). As discussed in the NRC staff’s ADR (NRC, 2008a) and in the supplement 

in Section 1.2.1, the NRC staff accepted the DOE analysis of contaminant releases from the 

repository based upon DOE’s TSPA model. Additional information on disposal assumptions can 

be found in responses to comments concerning waste containers and packages in Sections 

B.2.2.2.1, B.2.2.3.3, and B.2.4.6.3. A discussion of the use of the TSPA and other model 

results to support the supplement can be found in Section 1.2.2, Appendix A, and in 

Appendix B, Section B.2.2.2. Furthermore, several of the issues raised by commenters are the 

subject of contentions pending in the suspended adjudicatory proceeding. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(034, 117, 147-04, 147-07, 147-15, 149-20) 

B.2.3 Affected Environment

B.2.3.1 General Scope 

B.2.3.1.1 COMMENT: Commenters were concerned that the draft supplement focuses on 

impacts beyond the 11-mile postclosure compliance location and suggested that the 

supplement analysis be expanded to include estimates of impact to groundwater beneath the 

repository location, in the controlled area, and along the groundwater path to the point of 

compliance. These commenters stated that it is unreasonable to allow any level of groundwater 

contamination between the repository and the compliance location. One commenter stated that 

that ignoring such contamination is not consistent with how Nevada implements its laws. One 

commenter also stated that failing to disclose such impacts is not allowed under the Nuclear 

Waste Policy Act. Two commenters questioned the assumption that there will be no well drilling 

for water within the area between the repository and the compliance location; one commenter 

pointed out that DOE has already drilled for water within the controlled area, and another 

commenter stated that assumptions based on well drilling characteristics and pumping costs are 

unsupported. These commenters argued that it is implausible to assume that passive 

institutional controls will continue into the long-term future, and that population growth will be 

limited in the area near the repository site. 

RESPONSE: The NRC staff acknowledges these concerns regarding the spatial extent of the 

affected environment considered for the supplement analysis. These comments are outside the 

scope of the supplement, which concerns an assessment of the potential impacts to 

groundwater and surface discharges of groundwater beyond the postclosure compliance 

location, which is 18 km [11 mi] from the Yucca Mountain project site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029), and in the NRC staff’s ADR (NRC, 2008a). 

In its 2002 EIS and 2008 supplemental EIS, DOE described the affected environment and 

analyzed impacts for the area along the flow path from the repository to the postclosure 

compliance location. At the postclosure compliance location, DOE estimated the impacts for the 

reasonably maximally exposed individual (RMEI), consistent with the RMEI characteristics in 

10 CFR Part 63. As described in its ADR, the NRC staff determined that it could adopt DOE’s 
B–48 

evaluation of potential groundwater impacts from the repository to the postclosure compliance 

location. However, the NRC staff concluded that the affected environment and any impacts for 

areas beyond the postclosure compliance location were not adequately addressed in DOE’s 

EISs for potential releases of radiological and nonradiological contaminants from the repository 

to groundwater and from surface discharges of groundwater. 

No changes were made to the supplement text in response to these comments. 

(080-10, 132, 148) 

B.2.3.1.2. COMMENT: One commenter stated that the draft supplement fails to adequately 

describe the affected environment, as required by NEPA. The commenter stated that the 

supplement text and figures do not indicate that the postclosure compliance location and 

Amargosa Farms pumping locations are within the town of Amargosa Valley, and that the 

groundwater impacts would be heavily concentrated within the town of Amargosa Valley. The 

commenter went on to state that this is an omission because the population of the town is larger 

than other populated areas shown on the maps (e.g., Beatty and Indian Springs). The 

commenter further asserted that the supplement does not acknowledge or describe potentially 

affected privately owned lands and associated water wells in the vicinity of the pumping 

location, nor does it describe the potential social and economic impacts on these resources. 

The commenter provided figures indicating the locations of privately owned lands and wells and 

stated that the final supplement must include a description of these resources. 

RESPONSE: The commenter is correct that the postclosure compliance location, located 

18 km [11 mi] southeast of the repository site, as well as the Amargosa Farms area, lie within 

the boundaries of the unincorporated township of Amargosa Valley, which encompasses a large 

area of 1308 km2

 [505 mi2]. While the DOE SEIS (DOE, 2008a) calculated groundwater 

impacts only at the postclosure compliance location, the supplement calculates impacts at 

additional locations within the affected environment, including for Amargosa Farms, 35 km 

[22 mi] southeast of the repository site, within the town of Amargosa Valley. As explained in the 

supplement in Section 3.1, this location was chosen to represent potential impacts from 

groundwater pumping for agricultural and other uses in Amargosa Valley. Consistent with 

NRC’s NEPA-implementing regulations (10 CFR Part 51) and guidance (NRC, 2003), this 

location was chosen in order to focus on baseline conditions to assess impacts such that the 

detail incorporated is commensurate with the significance of the potential impacts. As 

discussed in the supplement, the NRC staff’s analysis assessed impacts to the population and 

not impacts to individuals or groups within that population. For this analysis, specific 

consideration of privately owned lands and associated water wells in the vicinity of the pumping 

location is not necessary, given the representative nature of the NRC staff’s calculations, the 

conservative assumption that the entire contaminant plume is captured by the well withdrawal, 

and the small impact on groundwater in Amargosa Valley calculated in the supplement. 

The NRC staff used the characteristics of the present-day population in the town of 

Amargosa Valley to represent possible future populations that may be affected by releases from 

the repository, consistent with the description of the reasonably maximally exposed individual in 

40 CFR 197.21 and 10 CFR 63.312. This approach also is consistent with recommendations of 

the National Academy of Sciences (NAS, 1995) on treatment of future populations for 

calculations over long time frames. The location for Amargosa Farms used in the supplement is 

conservative in that it represents the current population cluster along the groundwater flow path 

from Yucca Mountain in the area south of Highway 95 that is closest to the repository. Other 

current clusters of population and irrigation sites are farther down the groundwater flow path 
B–49 

and would therefore experience lesser estimated impacts for the same groundwater 

pumping assumptions. 

In response to this comment, multiple changes have been made to the supplement text and 

figures to improve clarity. These changes include clarification of the relationship between the 

Amargosa Farms area and the town of Amargosa Valley, and modification of location labels on 

Figures 2-1, 2-3, and 2-5. 

(148) 

B.2.3.2 Water Resources 

B.2.3.2.1. COMMENT: One commenter stated that the groundwater flow paths will not be 

static and will migrate as Fortymile Wash is activated in future wetter climates. The commenter 

also suggested that (i) the draft supplement lacks analysis that would account for conditions 

resembling those in the region’s geologic history, such as flowing river channels and a large 

lake in Death Valley sustained by runoff from Amargosa River; (ii) recharge during future wetter 

climates will cause the flow paths to shift – the commenter referred to a three-point solution 

presented in a contention (referred to as TIM-NEPA-004) that supports the flow path under 

Yucca Mountain shifting direction to the southwest from the current southeasterly flow; (iii) use 

of the DVRFS for modeling future flow pathways is not appropriate because the model does not 

adequately account for recharge and was calibrated to static conditions, not the dynamic 

conditions that the commenter states should be expected in future climates; and (iv) a regional 

watershed-based infiltration model should have been coupled with an appropriately modified 

DVRFS model to reflect future conditions. 

RESPONSE: The NRC staff agrees with the commenter that recharge occurs along channels 

during occasional flooding events in Fortymile Wash, and that in future wetter climatic 

conditions, recharge along the channel will increase due to seasonal or perennial channel flow. 

The NRC staff also agrees that the seasonal-to-perennial flow in the Amargosa River system, of 

which the Fortymile Wash is a tributary, along with increased groundwater discharge likely were 

the primary contributors to the formation of a paleolake in Death Valley during past wetter 

climates. The NRC staff, however, disagrees with the commenter with regard to the likelihood 

that recharge along Fortymile Wash during wetter climates could dramatically change the 

direction of the water table gradient beneath Yucca Mountain and Fortymile Wash because a 

water table rise to a planar surface is inconsistent with the hydrogeologic flow in the region, as 

discussed below. The term “water table” as used here is synonymous with the potentiometric 

surface for the uppermost aquifer as used by the commenter. 

The commenter refers to a first-order (planar) three-point extrapolation of nominal sites of 

former surface discharge under wetter climates to support a dramatic change in flow direction 

(and thus impacts on groundwater) in a wetter future climate. As discussed in the supplement 

in Sections 2.3.4 and 2.4, the NRC staff analysis uses the regional water table reconstruction 

from Paces and Whelan (2012) and the hydrogeologic conceptual models developed over the 

past several decades by the U.S. Geological Survey (USGS) (Belcher and Sweetkind, 2010, 

and references therein). These studies support a flow system constrained by faults, changes in 

lithology, variably distributed recharge, and other hydrogeologic features that influence flow 

directions. The ability of the USGS models to reproduce water table positions measured in 

wells across the Death Valley region supports the hydrogeologic features upon which the 

numerical models are built. 
B–50 

The commenter also suggests that the estimates of recharge from a Maxey-Eakin elevationcontrolled type model do not adequately reflect focused recharge along channels, and, thus, 

could not predict the water table rise indicated by the three-point solution. The commenter 

further states that recharge input for the groundwater flow model used in the supplement should 

have been estimated by a distributed watershed model, such as the Hevesi et al. (2003) 

infiltration model. The NRC staff notes that the Belcher and Sweetkind (2010) model used for 

the analyses in the supplement does not use a Maxey-Eakin relationship for estimates of 

recharge across the modeling domain, but rather, uses the Hevesi et al. (2003) model. The 

Hevesi et al. (2003) infiltration model indicates that recharge is highest at ridges and mountains 

(i.e., higher elevations) where soil layers are thin, and that recharge is lowest in alluvial basins. 

In addition, the NRC staff disagrees with the commenter that the infiltration and saturated zone 

models need to be directly linked to produce results appropriate for use in the supplement, 

particularly considering the long time frames considered for the modeling (thousands to a million 

years). Use of average infiltration results is warranted by the large difference in time constants 

for infiltration and for saturated zone flow processes. For example, the long time-constant for 

saturated flow reflects the slow response of aquifers to variations in precipitation, compared to 

the fast response of infiltration to rain events. 

In summary, the analysis presented in the supplement for the behavior of the flow system under 

a future cooler, wetter climate is supported by modeling and studies of the hydrogeologic 

system, as documented in the references cited in the supplement. 

No changes were made to the supplement as a result of these comments. 

(148) 

B.2.3.2.2. COMMENT: One commenter stated that groundwater transport pathways exist 

from Yucca Mountain eastward to Indian Springs Valley, under Sheep Creek Mountains, and 

into Coyote Springs Valley. The basis for the commenter’s statement is uncertainty shown on 

Figure 2-3 on page 2-7 of the draft supplement for flows between basins to the east of 

Amargosa Desert in the DVRFS model. This commenter stated that the impacts to water users 

in Lincoln County must be evaluated in the draft supplement. 

RESPONSE: Section 2.2.2 and Figure 2-3 in the supplement describe the general direction of 

flow from Yucca Mountain as being southward along Fortymile Wash (in the Fortymile Canyon 

Section, 3a) and across Amargosa Desert (in the Amargosa River Section, 3b) to the eastern 

end of the Funeral Mountains, and then southwesterly into Death Valley (in the Funeral 

Mountain Section, 3d). As described in the supplement in Sections 2.6 and 3.1.1, when no 

pumping occurs in the Amargosa Desert, the potential contaminant plume from the repository 

continues into Death Valley. When pumping occurs in the Amargosa Farms area, the entire 

plume is assumed to be captured by the pumping. Within the Death Valley Regional 

Groundwater Flow System (Belcher and Sweetkind, 2010), water from Section 3a does not flow 

eastward into Sections 2e or 2f, and, therefore, contaminants from the repository would not 

reach Indian Springs Valley (Section 2c). The uncertainty expressed in Figure 2-3 of the 

supplement represents local uncertainty at the southern part of the boundary between Sections 

2c and 2a. Coyote Springs Valley is on the eastern side of Sheep Range, and is partially 

contained within Section 2a. Based on the conceptualization in Belcher and Sweetkind (2010), 

and considering the areas contained on Figure 2-3 in the supplement, Coyote Springs Valley 

receives its groundwater from the north and from recharge in the Sheep Range. Therefore, the 
B–51 

NRC staff concludes that there would not be impacts to the Lincoln County groundwater system 

from a repository at Yucca Mountain. 

No changes were made to the supplement in response to this comment. 

(123) 

B.2.3.2.3. COMMENT: Many commenters stated that flow between basins as 

characterized in the DVRFS is misrepresented or uncertain, and thus affected environments or 

impacts were not properly considered in the draft supplement. 

Several commenters stated that new analyses presented in a report titled “2014 State of the 

Basin Report Amargosa River Basin” (Zdon and Associates, 2014) shows that groundwater 

flows from Amargosa Desert into the Southern Death Valley Subregion (SDVS), which includes 

the springs of Middle Amargosa Basin (Tecopa and Shoshone areas). A commenter provided a 

full copy of the report to the NRC. These commenters indicated that by misstating flow between 

Amargosa Desert and the SDVS, the draft supplement fails to analyze exposure pathways and 

impacts along the Amargosa River south of Alkali Flat, including impacts to ecology and 

communities over the one-million-year analysis period. The commenters further stated that the 

draft supplement failed to analyze potential changes associated with seismic activity over the 

one-million-year period. 

Additionally, referencing Section 2.2.2 of the draft supplement, several commenters emphasized 

that the springs in the Middle Amargosa Basin are misrepresented in the draft supplement as 

small and intermittent. Noting line 19 on page 2-6 of the draft supplement, one commenter 

requested an estimate of the flow between the two basins in acre-feet/year. 

Two commenters disagreed with the comments described above by stating that the 

groundwater flow pathways that contaminants from the repository would follow are not to 

Shoshone and Tecopa in the Lower Amargosa River Valley, but rather under the Funeral 

Mountains to Furnace Creek springs, as represented by the DVRFS-2010 model. Another 

commenter commended the NRC and DOE for credibly extending the analysis to the accessible 

environment and, in particular, by including analyses from the commenter’s published reports on 

the Lower Carbonate Aquifer and Death Valley hydraulic studies. 

RESPONSE: The analyses in Zdon and Associates (2014, 2015) are generally consistent with 

the conceptualization of flow in the supplement. In the description in the supplement 

(Section 2.2), groundwater from below the repository flows southward beneath Fortymile Wash 

and transitions at the junction with Amargosa River from the alluvial aquifer of the Amargosa 

Farms area to the carbonate aquifer at the eastern end of the Funeral Mountains. The 

groundwater pathway then follows the regional carbonate gradient southwesterly towards the 

springs near Furnace Creek and on to Middle Basin in Death Valley. The likelihood of flow 

through the carbonate blocks at the southeastern end of the Funeral Mountains was identified 

through research conducted by the USGS (Belcher and Sweetkind, 2010) and an Inyo County 

drilling program (Inyo County, 2007). Bredehoeft et al. (2008) defined properties of the 

relatively permeable carbonate units within the Funeral Mountains. Further support for the 

hydrologic connection between the southerly flowing alluvial aquifer in the Amargosa Desert and 

the carbonate aquifer beneath the Funeral Mountains is the presence of freshwater carbonates 

in the State Line paleospring deposits, as described in Paces and Whelan (2012). A likely 
B–52 

source of groundwater forming these deposits during wetter past climates are the carbonate 

blocks of the eastern end of the Funeral Mountains. 

Zdon and Associates (2014) focused on identifying sources of water for springs in the Middle 

Amargosa River Basin. They conclude, besides the primary contributions from the east 

(e.g., the Spring Mountains), that the contribution from Amargosa Desert to the north was 

derived from Ash Meadows (see also Zdon et al., 2015; Zdon and Associates, 2015). The NRC 

staff notes that geographically, the Amargosa Desert encompasses both Ash Meadows and the 

Amargosa Farms area. However, as demonstrated in the Death Valley Regional Groundwater 

Flow System (Belcher and Sweetkind, 2010), these two areas are hydrologically separated by a 

large fault and coincident steep hydraulic gradient dipping approximately west to southwest. 

This feature was the primary basis for the NRC staff’s conclusion in the supplement in Section 

2.2.2 that the groundwater from below the repository flowing southward beneath Fortymile 

Wash does not enter the Ash Meadows area and would not, therefore, be a component of flow 

from Ash Meadows to the Middle Amargosa River Basin and the springs near Shoshone 

and Tecopa. 

The Zdon and Associates (2014, 2015) reports contain isotopic, noble gas, major ion, and trace 

element data from multiple locations in the Middle Amargosa River Basin and adjacent areas in 

Nevada. Contrary to the assertions in some of the comments, the geochemical data presented 

in these reports are entirely consistent with previous interpretations of groundwater flow paths, 

recharge sources, and regions of mixing that are described in the supplement, including the 

separation between the predominant repository flow path and the flow from Ash Meadows 

towards the Middle Amargosa River Basin, and ultimately the Shoshone and Tecopa areas. 

The geochemical data, especially the stable isotope data, suggest that the source for the 

groundwater beneath the Amargosa River Valley is limited to either the Spring Mountains, or is 

a mixture of Ash Meadows, Spring Mountains, and Kingston Range groundwater (Davisson and 

Associates, 2014; Zdon and Associates, 2014, 2015; Larsen et al., 2001). These mixing and 

source waters do not travel along the relatively shallow alluvial system beneath the Amargosa 

River channel but through the regional carbonate aquifer system. From a comparison of 

isotopes in the groundwater near springs in the Tecopa area with data from an upstream well in 

Amargosa River channel sediments, Davisson and Associates (2014) suggest that an alluvial 

flow path beneath the river channel would be, at best, a minor contributor to the Amargosa River 

Valley groundwater system. Furthermore, Zdon and Associates (2015) and Davisson and 

Associates (2014) suggest that the springs at Tecopa are supported by water from a fracture 

flow system with a deep source of water, consistent with the helium isotope ratios and the 

extent of mixing from different sources. These data from the Zdon and Associates report from 

the springs in the Middle Amargosa River Basin reflect a strong influence of recharge from the 

Spring Mountains and provide additional evidence of contributions from the same recharge 

source that produces discharge at Ash Meadows (Davisson and Associates, 2014). These 

Zdon and Associates conclusions are entirely consistent with the conceptual model and 

analyses presented in the supplement. 

The supplement considers the uncertainty in groundwater flow paths south of Amargosa Farms 

in the treatment of impacts in the no-pumping analysis case (Section 3.1.2). In addition to 

considering the conceptualization in the DVRGFS model (Belcher and Sweetkind, 2010) that 

most of the groundwater flow south of Amargosa Farms is under the Funeral Mountains, the 

supplement also discusses impacts for a limited amount of flow to Alkali Flat/Franklin Lake 

Playa. As discussed in the supplement in Sections 2.2.2 and 2.3.4, Alkali Flat/Franklin Lake 

Playa lies along the surface trace of the Amargosa River at the confluence with Carson Slough, 
B–53 

which flows from Ash Meadows. Most of the groundwater traveling along the Amargosa River 

pathway, as well as that along Carson Slough, is lost through evapotranspiration as it reaches 

the structural constriction associated with the Eagle Mountain pass. The supplement addresses 

potential impacts of contaminants reaching Alkali Flat/Franklin Lake Playa (Section 3.1.2.3), but 

as discussed in the supplement, there is no indication that a contaminant plume from the 

repository would persist in groundwater beyond that location towards the Middle Amargosa 

River Basin. This is consistent with the geochemical data in Davisson (2014) and Zdon and 

Associates (2014, 2015). 

One commenter, referring to text on page 2-6 of the supplement, requested quantification of the 

volumetric groundwater flow (in acre-ft/yr) from Yucca Mountain in the Central Death Valley 

Subregion that reaches the location where the Amargosa River crosses into the Southern Death 

Valley Subregion, which is immediately south of Alkali Flat. While a tracer test to estimate this 

flow rate in the field is not feasible, in its groundwater reports, Sandia National Laboratory 

performed a particle tracking simulation using a flow field from the DVRFS model (Belcher and 

Sweetkind, 2010), essentially performing a numerically simulated tracer test. As described in 

Section 2.2.2 of the supplement, for 10,000 particles released at Yucca Mountain in an analysis 

by SNL (2009), 8,024 reached the postclosure compliance location. Only 2 particles reached 

Alkali Flat (SNL, 2009). This indicates that approximately 0.02 percent of the groundwater 

beneath Yucca Mountain reaches the Amargosa River at the boundary to the Southern Death 

Valley Subregion. The NRC staff considers this value to be uncertain, but reflective of the 

relative magnitude of flow from Yucca Mountain to Alkali Flat. 

Uncertainties of flow patterns in southern Amargosa Desert may be reduced by future studies. 

The ongoing SAMM (USGS, 2016a) and LAV (USGS, 2016b) projects led by the 

U.S. Geological Survey both concern groundwater flow in the southern part of the Death Valley 

region. The Southern Amargosa eMbeddded Model (SAMM) is a modeling effort to refine the 

hydrogeologic framework and flow conceptualization for an area including Amargosa Farms 

and Ash Meadows and extending southward into eastern Funeral Mountains and Middle 

Amargosa River Basin. The SAMM project will include analysis of the hydrologic connection 

between Ash Meadows and Amargosa Farms. The LAV project focuses on the primary 

groundwater sources and generalized flow paths that support discharge in the Lower 

Amargosa Valley (Eagle Mountain to Tecopa section). These projects may provide additional 

information on pathways for flow southward from the alluvial aquifer in the Amargosa Farms 

area. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. As a result of the in-progress studies or other developments, information 

may be identified that requires further supplementation of DOE’s 2002 and 2008 EISs in the 

future. The completion of licensing activities is subject to appropriations and other actions 

external to the NRC. 

The NRC staff revised the description in Section 2.2.2 (subsection titled Alkali Flat and Southern 

Death Valley Subregion) to clarify that sections of the Amargosa River are perennially flowing 

due to springs along the Shoshone and Tecopa areas. The NRC staff revised the supplement 

text in Section 2.3.3 (subsection titled Discharge Locations along the Flow Path South from 

Amargosa Farms) to include the provided reference and discuss the additional data provided in 

the Zdon et al. (2015) and Zdon and Associates (2014, 2015) reports. 

(042, 046, 061, 080-10, 121, 134, 142, 143, 149-10, 149-1601, 149-21) 
B–54 

B.2.3.2.4. COMMENT: One commenter pointed out a discrepancy between the 

commenter’s documented estimate of spring discharge in the Furnace Creek area and the 

estimate provided in the draft supplement. The commenter also noted a discrepancy in 

estimates of evapotranspiration, but indicated that the value used in the supplement is larger 

and represents a worst case for radionuclide transport. 

RESPONSE: The NRC staff appreciates the additional estimate of spring discharge provided 

by the commenter. Measurement of spring discharge at the Furnace Creek area and 

evapotranspiration at Middle Basin is uncertain because of the complex nature of the 

groundwater flow discharging at the ground surface. For spring discharge, the commenter 

suggested a value of 5 cfs [3,600 Ac-ft/yr; 4.4 x 106 m3/d] combined for seven springs in the 

area and provided a report supporting that estimate (Jensen et al., 2004). The supplement 

utilized a value of 3.2 cfs [2,294 Ac-ft/yr; 2.8 x 106

 m3/d] that was derived from the three 

prominent springs (Travertine, Nevares, and Texas) reported in Belcher et al. (2010; Table C-2). 

The difference in the estimates is primarily due to differences in discharge estimates for each of 

the three prominent springs and not due to the inclusion of seven springs instead of three. As 

noted by the commenter, the use of the smaller value of discharge from the springs is 

conservative in that it leads to larger calculated values of contaminant concentration and dose. 

The value of the evapotranspiration estimates provided in the supplement and that suggested 

by the commenter represent different quantities. The commenter’s estimate of 

evapotranspiration was derived from irrigation demand in the Furnace Creek area, where water 

discharging from the springs is used for agricultural irrigation. In Section 3.1.2.2 of the 

supplement, the NRC staff analysis treats Middle Basin in Death Valley as a separate affected 

environment with different exposure pathways from that used for the Furnace Creek area. The 

evapotranspiration estimate in the supplement for Middle Basin represents evaporation of 

groundwater as the water table approaches the ground surface and transpiration from native 

plants such as creosote bush. The evapotranspiration estimate used in the supplement 

covers a broad area downslope of the Furnace Creek springs area and out to the salt pan of 

Death Valley. 

In response to this comment, Section 2.3.3 of the supplement has been revised to acknowledge 

the larger value of spring discharge reported in Jensen et al. (2004). The discharge value from 

Belcher et al. (2010), however, is still used in the calculations of impacts at Furnace Creek area. 

No change was made in the supplement pertaining to the value of evapotranspiration at 

Middle Basin. 

(142) 

B.2.3.2.5. COMMENT: Several commenters stated concerns related to the draft 

supplement’s assumptions for groundwater pumping. One commenter questioned the 

statement in the draft supplement that current pumping rates in Amargosa Farms may not be 

sustainable because water levels at Devils Hole are approaching the level constrained by the 

State Engineer’s order. The commenter maintained that estimates from the DVRFS modelderived estimates of declining water levels in Ash Meadows due to pumping in surrounding 

areas are inaccurate, and that nonpumping related consumptive use should be considered 

along with pumping in the DVRFS model calibration. The commenter provided a hydrograph of 

water levels at Devils Hole in Ash Meadows covering the past 50 years that indicates slightly 

increasing water levels over the past decade. Other commenters suggested that pumping in 

Amargosa Farms does not impact water levels in Ash Meadows because the areas are 
B–55 

separated by a fault system. As with the previous commenter, these commenters noted that 

water levels are declining in the Amargosa Farms area and slightly increasing in Ash Meadows. 

One commenter suggested that it is unrealistic to rely on future restrictions of pumping for 

preservation of the Devils Hole pupfish, as indicated in the draft supplement, and further 

suggested that a wetter future climate will result in greater groundwater use because perennial 

yield1

 would increase. Another commenter pointed to potential changes in groundwater levels 

should water rights in Amargosa Farms be fully exercised or if the region’s solar energy 

production potential is realized. Another commenter requested that during construction of the 

repository, the flow pathways should be thoroughly delineated along Fortymile Wash and 

through the Amargosa Farms area. 

One commenter suggested that the DVRFS model used in the supplement could not 

appropriately represent the effects of future (continued) pumping in Amargosa Desert because it 

was calibrated to water levels observed in the mid-1990s, and that it is only capable of 

generating steady-state water levels that do not account for the impacts of pumping. The 

commenter cited Bredehoeft and King (2010), stating that continued pumping in 

Amargosa Desert would significantly decrease the vertical gradient between the carbonate and 

tuff aquifers below Yucca Mountain. Reversal of the gradient would lead to repository releases 

entering the carbonate aquifer and moving quickly to Death Valley. 

RESPONSE: The effects of pumping on potentiometric conditions below Yucca Mountain, 

including the reversal of the vertical gradient between the carbonate and overlying volcanic 

aquifers is outside the scope of this supplement. The scope of the supplement concerns an 

assessment of the potential impacts to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain 

project site. The scope of this supplement is further described in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

With respect to the effects of pumping on groundwater conditions and pathways beyond the 

postclosure compliance location, such as at Ash Meadows, assumptions regarding future 

pumping rates in the supplement are based on present and historical records over the past 

several decades. The NRC staff chose this approach for estimating future pumping rates to be 

consistent with discussions in the National Academy of Sciences 1995 report (NAS, 1995) to 

avoid speculative projections caused by difficulties in projecting future societal behavior. A 

present-day constraint on pumping rates includes the State of Nevada Engineer’s order 

(Taylor, 2008) related to water levels in Devils Hole. The NRC staff considers it speculative to 

assume that the order will be rescinded. The NRC staff did not quantify the relationship 

between pumping rates in Amargosa Farms and water levels in Devils Hole because Ash 

Meadows is not part of the affected environment considered in the supplement. The NRC staff, 

however, agrees with the commenters that stated that a fault system that lies between Ash 

Meadows and Amargosa Farms influences the hydraulic connection between the two areas. 

The fault system and distribution of water table elevations across the fault inform the conclusion 

in the supplement in Section 2.2.2 that the groundwater flow pathway from Yucca Mountain 

does not include Ash Meadows. In addition, cumulative impacts from pumping and possible 

contamination related to potential solar projects in Amargosa Valley are considered in the 

supplement as possible cumulative impacts in Section 4.4.2. 

 

1

Perennial yield is the maximum amount of groundwater that can be withdrawn over a period of time without depleting 

the groundwater reservoir. 
B–56 

With regard to the commenters’ request for more thoroughly defined groundwater flow paths in 

Fortymile Wash and Amargosa Farms area, the designation of the Middle Amargosa River as a 

Wild and Scenic River has generated additional interest and research in groundwater flow in the 

southern extent of Amargosa Desert (e.g., development of the Southern Amargosa eMbedded 

Model, http://nevada.usgs.gov/water/studyareas/samm.htm) over the past years. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. 

As discussed in the supplement in Section 1.2 and in the NRC staff’s ADR (NRC, 2008a), the 

nature of the vertical gradient between the aquifers below Yucca Mountain is out of scope for 

this supplement. Nonetheless, the NRC staff notes that modeling reported in SNL (2009) 

provides relevant analysis using an updated version of the DVRFS model. As described in 

Section 2.4 of the supplement, SNL (2009, Table 8) provided results that suggest an 

insignificant effect on vertical gradients below Yucca Mountain when pumping for 500 years 

concurrently from both Amargosa Farms and from external basins (i.e., SNWA inter-basin 

transfers; see Section B.2.4.1.11). In addition, using a steady-state approximation, SNL 

(2009, Table 8) similarly showed an insignificant effect on the vertical gradient near Yucca 

Mountain. The commenter stated that their modeling of pumping in Amargosa Valley for 

1,000 years into the future, using Belcher’s (2004) DVRFS model, indicates a drop of 10 m 

[33 ft] in the potentiometric surface of the carbonate aquifer below Yucca Mountain [Bredehoeft 

and King, 2010]. The commenter did not, however, provide estimated hydraulic head changes 

for the overlying volcanic aquifers that would allow for calculation of changes to the vertical 

gradient between the two aquifers. 

The same commenter suggested that the model used in the supplement was incapable of 

accounting for the effect of future pumping. Both the DOE and NRC environmental evaluations 

assess potential changes to the vertical gradient over the flow domain from Yucca Mountain to 

the Amargosa River. SNL (2009) used an updated version of the DVRFS model that included 

transient calibration of pumping and well data from 1913 to 2003. SNL (2009) did not use the 

DVRFS model to provide boundary conditions to the Site Scale Saturated Flow Model 

(DOE, 2008b, Section 2.3.9) for the analysis of future pumping effects. DOE’s approach in its 

performance assessment (DOE, 2008b, Section 2.3.9), however, did link the DVRFS and SiteScale Saturated Flow models. The NRC staff’s discussion of groundwater modeling is in 

Section 2.4 of the supplement. 

No changes were made to the supplement in response to these comments. 

(046, 049, 142, 149-13, 149-18) 

B.2.4 Environmental Impacts 

B.2.4.1 Water Resources 

B.2.4.1.1. COMMENT: A commenter stated that the only significant exposure pathway 

occurs through groundwater that lies entirely within the Nye County community of 

Amargosa Valley, and that impacts for those pathways are small. The commenter noted that 

pumping in Amargosa Valley will likely continue in the future, and that it would capture all the 

contaminants that may be released from the repository. The commenter concluded that, 
B–57 

therefore, no contamination would occur now or in the future at locations downstream of 

Amargosa Valley (e.g., to California and Death Valley). The commenter also provided a map 

that included groundwater flow path lines from the nuclear test areas to surface discharge 

areas. The commenter recommended visiting the Nye County Nuclear Waste Repository 

Project Office Web site for information about groundwater, based on data from 44 wells in 

Nye County. 

RESPONSE: The NRC staff agrees with the commenter that the only significant exposure 

pathway would be in Amargosa Farms if pumping in that area continues at levels observed in 

the past several decades. However, the NRC staff considered the possibility that future 

pumping may decrease, whether as a result of the number of wells or the pumping rates at 

those wells. At some point, decreased levels of pumping may allow some contaminants in the 

groundwater to pass the Amargosa Farms area and continue downstream in the groundwater 

system. To evaluate the impacts from this possibility, the NRC staff assumed the extreme case 

of no pumping, which would maximize contaminant transport downstream of Amargosa Farms. 

The rationale for this assumption, as discussed in the supplement, is that if no pumping led to 

small impacts at affected environments downstream of Amargosa Farms, then pumping at some 

intermediate level would lead to less impacts. At an intermediate pumping level, some 

radionuclides and metals would be withdrawn in groundwater at Amargosa Farms (where 

pumping occurs) and others would continue to move downstream (e.g., Stateline Deposits area 

or Furnace Creek springs). 

With regard to information from Nye County, the NRC staff acknowledges the map of 

groundwater flow path lines to surface discharge areas and appreciates Nye County making 

information from its drilling programs available on its Web site. Information from Nye County’s 

past drilling programs has been helpful to the NRC staff for understanding the characteristics of 

groundwater flow in the Amargosa Desert. 

No changes were made to the supplement as a result of these comments.

(106, 149-16) 

B.2.4.1.2. COMMENT: One commenter suggested that for surface water discharges 

described as potable, the supplement should refer to guidelines for total dissolved solids 

contained in the Environmental Protection Agency’s National Secondary Drinking Water 

Regulations. The commenter noted that the secondary maximum contaminant level for TDS is 

500 ppm. 

RESPONSE: The NRC staff agrees with the commenter that the maximum TDS level listed in 

the National Secondary Drinking Water Standards (NSDWS) set by the Environmental 

Protection Agency is the appropriate reference for the discussion of water quality at Alkali Flat in 

Section A.2.2 of the supplement. The NSDWS provide guidelines for aesthetic qualities 

(i.e., taste, smell, appearance) of drinking water. The TDS standard was changed from 250 to 

500 ppm in Appendix A, Section A.2.2, and additional clarifying text was added in response to 

this comment. 

(137) 

B.2.4.1.3. COMMENT: A commenter expressed concern that the postclosure compliance 

location is located 11 miles downstream of the repository site and stated that this distance is 
B–58 

needed to reduce contamination through dilution. The commenter stated that the proposed 

repository could only meet legal requirements through this dilution of radioactivity for 11 miles, 

also noting that contamination would extend beyond the compliance point. The commenter 

argued that the groundwater flow is too low to provide sufficient dilution. 

RESPONSE: The NRC staff acknowledges the concern expressed by two commenters about 

the 18-km [11-mi] postclosure compliance location and the extent of dilution that may reduce the 

concentration of radionuclides in the groundwater between the repository and the compliance 

location. These comments are outside the scope of this supplement, which concerns an 

assessment of the potential impacts to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 

The NRC staff reviewed groundwater flow and transport to the compliance boundary in the NRC 

staff’s SER (2014a, Sections 2.2.1.3.8 and 2.2.1.3.9). DOE’s use of the compliance location is 

a requirement in NRC regulations. The accessible environment begins at the postclosure 

compliance location and is any area outside of the controlled area. The controlled area in the 

direction of groundwater flow is defined in 10 CFR 63.302 as the location no further “(s)outh 

than 36°40'13.6661" North latitude.” The NRC staff assessed DOE’s calculation of radionuclide 

transport from the repository to the compliance location in Volume 3 of its SER (NRC, 2014a). 

With respect to the commenters’ claims regarding dilution to the postclosure compliance 

location, dilution is a natural process, the extent of which depends on the site-specific 

characteristics of the groundwater flow system. Dilution occurs when the groundwater carrying 

contaminants mixes with water flowing from other areas and thus is a mechanism that reduces 

concentrations of contaminants in the groundwater. At Yucca Mountain, radionuclides released 

from the repository would be carried downward through the unsaturated zone to meet a much 

larger volume of groundwater flowing horizontally in the underlying aquifer. The easterly to 

southeasterly flow in the aquifer below the repository converges with the much larger southerly 

flow in the aquifer below Fortymile Wash. Whereas the DOE models in the license application 

(DOE, 2008a,b) could have accounted for the characteristics of the groundwater flow system 

that may lead to dilution between the repository and the postclosure compliance location, DOE 

instead estimated the mass flux of radionuclides at the compliance location to facilitate 

estimation of dose, as required by NRC regulations. Dilution between the repository and 

compliance location is thus not considered in calculations of mass flux arriving at the 

postclosure compliance location. Because the regulations also include criteria for water quality, 

DOE calculated radionuclide concentrations in its application at the postclosure compliance 

location using the radionuclide mass flux and an annual water demand (e.g., water pumped 

from wells) of 3,000 acre-feet/year, as specified in the NRC regulations (10 CFR 63.312). The 

mass flux of radionuclides, which does not consider dilution effects as discussed above, is used 

as a source term for the calculations in the supplement. 

Dilution downstream of the postclosure compliance location is similarly not calculated by 

characterizing the mixing of uncontaminated water with the contaminant plume, but rather is 

calculated in the supplement based only on the amount of discharge. The discharge at the 

affected environment is the pumping rate or seepage and evaporation of groundwater at the 

ground surface. The NRC staff conservatively assumes that the entire mass of radionuclides 

arriving at the affected environment is discharged with the water at each potential discharge 

location. 
B–59 

No changes were made to the supplement in response to these comments.

(095-12, 146-07)

B.2.4.1.4. COMMENT: One commenter stated that there is insufficient information to 

evaluate impacts because the Death Valley Regional Flow System (DVRFS) model uses a grid 

(1.5 km by 1.5 km) that is too coarse to accurately and adequately represent transport from the 

repository through the system to California. The commenter further stated that (i) grid 

refinement is needed because the contaminant of concern (not specified by the commenter) is 

high risk, and its behavior should be assessed at a finer resolution; (ii) the use of average 

velocities for the groundwater flow paths reduces the ability of the higher velocity flow paths to 

move contaminants faster, such as may be observed in a more detailed model; (iii) the grid 

resolution could easily be refined within the existing framework without causing undue 

computational burdens; and (iv) the SAMM (Southern Amargosa eMbedded Model, which is 

expected to be completed in 2016) is an example of a model within the DVRFS with a finer 

grid resolution.

RESPONSE: The NRC staff does not agree that an increased resolution of the grid of the 

DVRFS model would significantly change the estimates of impacts in the affected environments 

in the supplement. 

The impacts presented in the supplement reflect the maximum estimate at each potentially 

affected environment. Refining the grid and potentially creating a faster flow path in the model 

would change the timing of the arrival of radionuclides but not change the maximum value of the 

mass flux of radionuclides. Therefore, the timing of the estimated maximum impact does not 

affect the impact conclusions in the supplement. The staff also notes that the entire plume is 

conservatively assumed to be captured at an affected environment (e.g., Furnace Creek 

springs), so preferential flow and transport similarly do not affect the impact conclusions in the 

supplement. 

Also, the flow path from the repository to Death Valley includes some sections that are 

dominantly in fractured aquifers and other sections that are dominantly in granular aquifers. 

The commenter cited preferential flow and transport through aquifers composed of fractured 

rocks as an important reason to refine the DVRFS model grid. The first portion of the flow path 

covers flow through the fractured tuff aquifers from the repository to the compliance location 

where the flow path transitions into the alluvial aquifer of the Amargosa Desert. DOE’s license 

application utilized the site-scale saturated zone flow model for this portion of the flow path. The 

site-scale saturated zone flow model is composed of grid cells that are significantly smaller than 

those of the DVRFS model and primarily reflects flow through the fault and fracture network in 

the volcanic tuff aquifers in the immediate vicinity of Yucca Mountain. In the supplement, the 

NRC staff used breakthrough curves that derive, in part, from the flow field characterized by 

the site-scale saturated zone flow model to transport metals from the repository to the 

compliance location. The NRC staff’s evaluation of this approach can be found in NRC (2014a, 

Sections 2.2.1.3.8 and 2.2.1.3.9). 

The next segment of the flow path is through the alluvial aquifers of Amargosa Desert. Fault 

and fracture flow is not a significant feature of the alluvial aquifers (alluvial sediments are a 

granular porous media). The last segment of the flow path, from eastern the Funeral Mountains 

to Furnace Creek springs and Middle Basin of Death Valley, is primarily through a carbonate 

aquifer. Fast travel times through this aquifer are reflected in the calculations in the supplement 

because the aquifer’s low porosity is reflective of faults and fractures. Travel time is calculated 
B–60 

as the specific discharge divided by the porosity. In addition, the NRC staff assumed that the 

entire mass of radionuclides discharges to the ground surface at the springs of Furnace Creek 

for the no-pumping scenario. This is conservative in that it likely overestimates impacts at 

Furnace Creek, especially if preferential flow and transport are incorporated into the model, 

because some preferential pathways would bypass the springs. 

The NRC staff is aware of the ongoing U.S. Geological Survey projects assessing flow patterns 

in the southern portion of Amargosa Desert. One of these, the Southern Amargosa eMbedded 

Model (USGS, 2016a) would use a refined grid and would be linked to the DVRFS model. The 

other project, Lower Amargosa Valley (USGS, 2016b), focuses on source areas for water 

contributing to flow in the Lower Amargosa River, specifically in the section south of Alkali Flat 

that includes Tecopa and Shoshone. These two projects have not yet been completed. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement in response to this comment. 

(124) 

B.2.4.1.5. COMMENT: Two commenters mentioned the potential for contamination of 

water flowing in the Amargosa River during floods or future wetter climates. One commenter 

described instances of rain followed by areal flooding and expressed concern about the 

potential for groundwater to contaminate surface water during floods. Another commenter 

noted that the draft supplement describes portions of the Amargosa River channel becoming 

perennial streams during future wetter climates and suggested that the supplement should 

consider how the greater volume of water at receptor locations would affect impacts. The 

commenter indicated that the greater water volume makes the assumption of 100 percent 

capture of contaminants too conservative for any one location. 

RESPONSE: For analyses in the supplement under present-day climatic conditions, the NRC 

staff considers areas where groundwater discharges to the ground surface and is the sole 

source of water during much of each year. These areas include the Furnace Creek springs and 

Middle Basin in Death Valley. The groundwater discharging in these affected environments 

may mix with the transient, short-lived, surface water flow during flooding events, which as 

discussed below, would dilute the concentration of contaminants and reduce estimated impacts. 

For analyses in the supplement under future wetter climatic conditions, the NRC staff also 

considers discharge of groundwater to the ground surface at these Death Valley locations, as 

well as at the State Line Deposits area between the Amargosa River channel and the 

Amargosa Farms area. At the State Line Deposits area, some water from the past springs likely 

flowed into the Amargosa River channel during past wetter climates, thus contributing water to 

support perennial flow in the channel. Geologic evidence for hydrologic conditions in the past 

indicates that several sections of the Amargosa River were perennially flowing during past 

wetter climatic conditions, but do not support perennial flow over the entire length of the 

Amargosa River (Paces and Whelan, 2012). 

In either of these climatic states, transient, short-term flood events or perennial flow in sections 

of the river channel, groundwater containing radionuclides that discharge into a flowing river 
B–61 

would be substantially diluted. One commenter recommended that this dilution be considered in 

the supplement because it would significantly reduce the estimate of impacts. The NRC staff 

conservatively chose not to consider this dilution. Instead, the supplement assumes that the 

entire mass flux of radionuclides was made available to the exposure pathway directly linked to 

the undiluted groundwater discharge location. 

Additionally, the NRC staff interprets one commenter’s description of a location where 

groundwater is discharging to a flowing river as being the Middle Amargosa River section that 

includes Tecopa and Shoshone. As discussed in the supplement in Section 2.2.2, the flow and 

transport models indicate that radionuclides from Yucca Mountain are not likely to reach the 

alluvial groundwater system below the channel of this section of the Amargosa River. 

No changes were made to the supplement as a result of these comments. 

(138, 149-12) 

B.2.4.1.6. COMMENT: A commenter stated that the draft supplement failed to consider 

how the temporary storage of hazardous materials and radioactive waste at surface facilities 

could result in contamination of the Amargosa River in the event of a flood. This commenter 

indicated that a mitigation or remediation plan would be needed prior to the active preclosure 

phase to protect the public health.

RESPONSE: The NRC staff acknowledges the concerns expressed by the commenter about 

potential contamination of surface waters in the event of a flood during the preclosure 

operations phase at Yucca Mountain. This comment is outside the scope of the supplement, 

which concerns the potential impacts to groundwater and on surface discharges of groundwater 

beyond the postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain 

project site. The scope of this supplement is further described in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

DOE considered potential flooding events during operations and plans for mitigating flood 

control structures in its Safety Analysis Report (DOE, 2008b, Section 1.6.3.4.9). The NRC staff 

review of this analysis is given in its SER (NRC, 2015a; Chapter 3, Section 3.2.1.1.3). 

No changes were made to the supplement as a result of these comments. 

(124) 

B.2.4.1.7. COMMENT: Several commenters suggested that Yucca Mountain was either 

permanently closed because it failed applicable requirements, or it failed specifications due to 

water flow through the mountain and the potential for ground and surface water contamination. 

Commenters expressed concerns about standards having been changed because 

Yucca Mountain did not meet initially established requirements. One commenter provided 

citations to two articles on changed standards. Another commenter wondered how drip shields 

would help in the event of a flood in the repository.

RESPONSE: The NRC staff acknowledges commenters’ concerns about the standards and 

regulatory requirements applicable to the proposed repository at Yucca Mountain. These 

comments are outside the scope of the supplement, which concerns an assessment of the 

potential impacts to groundwater and surface discharges of groundwater beyond the 
B–62 

postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain project site. 

The scope of this supplement is further described in the NRC’s Notice of Intent to prepare the 

supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The status of the Yucca Mountain project is described in Section 1.1 of the supplement. In 

2010, the Secretary of Energy indicated that the Administration no longer intended to pursue a 

repository at Yucca Mountain. In 2011, Congress reduced funding for the NRC’s review, which 

led to an orderly closure of the NRC staff’s review of the license application and suspension of 

the adjudicatory proceeding. In August 2013, the U.S. Court of Appeals for the District of 

Columbia Circuit issued a decision directing the NRC to resume the licensing process for DOE’s 

license application using funds previously appropriated from the Nuclear Waste Fund. The 

NRC staff completed the SER in 2015 (NRC, 2010; 2014a,b; 2015a,b). 

The requirements that the NRC staff used for its evaluation in the SER are contained in the 

NRC regulation for Yucca Mountain (10 CFR 63), which are required to be consistent with 

EPA’s standards for Yucca Mountain (40 CFR 197). 

One commenter also referred to the use of man-made radioisotopes as tracers of water flow 

into the mountain, and that such information led to changes in standards for water entering the 

mountain. The NRC staff disagrees that the observations of radioisotopic tracers in the 

unsaturated zone at Yucca Mountain led to changes in criteria. Rather, DOE included the 

information from tracer studies in its safety analysis and indicated that they were consistent with 

its estimates and models of unsaturated flow and transport (DOE, 2008b, Section 2.3.2). The 

NRC staff review of this analysis is given in its SER (NRC, 2014a, Section 2.2.1.3.6) 

Another commenter also expressed concern with the ability of titanium drip shields to protect 

waste packages during flooding events in the drifts. In DOE’s design, the drip shields serve to 

divert water dripping from above away from the waste packages. DOE’s analysis considered 

flooding of the drifts as a very low probability event that could be excluded (SNL, 2008b) from 

the postclosure safety performance assessment consistent with the regulations in 10 CFR Part 

63. The NRC staff’s evaluation can be found in its SER (NRC, 2014a, Section 2.2.1.2.1.3.2). 

The preparation of this supplement is only one of several steps in the NRC’s licensing process 

for the proposed repository. The completion of licensing activities is subject to Congressional 

appropriations and other actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(072, 086, 095-01, 095-04) 

B.2.4.1.8. COMMENT: One commenter stated that Clark County is searching for additional 

water supply in surrounding rural areas, and that groundwater impacts from the proposed 

repository would, therefore, impact the Clark County water supply. 

RESPONSE: Southern Nevada Water Authority’s (SNWA) future plans include groundwater 

pumped from basins in Clark, Lincoln, White Pine, and northern Nye County, as summarized in 

SNWA (2015), which is described in more detail in Section B.2.4.1.11. Groundwater 

withdrawals and inter-basin water transfers from rural areas in eastern Nevada to Clark County 

were one part of SNWA’s plans to address estimated future water demands in Las Vegas. As 

evaluated in Chapter 3 of the supplement, impacts from the proposed repository are identified in 
B–63 

Nye County at Amargosa Farms and the State Line Deposits/Franklin Well area, and in Inyo 

County at the Furnace Creek springs and Middle Basin of Death Valley. No impacts were 

identified in the areas listed in SNWA’s plans (2015) (i.e., Clark, Lincoln, and White Pine 

counties, or northern Nye County). 

The groundwater flow and transport pathway from Yucca Mountain is described in Chapter 2 of 

the supplement. As noted in Section B.2.3.2.2, the regional groundwater flow is southwesterly 

(Belcher and Sweetkind, 2010). Groundwater from Yucca Mountain is not projected to flow 

eastward or northeastward to Clark, Lincoln, White Pine, or northern Nye County. Section 2.2.2 

and Figure 2-3 in the supplement describe the general direction of flow from Yucca Mountain as 

being southward along Fortymile Wash and across Amargosa Desert to the eastern end of the 

Funeral Mountains, and then southwesterly into Death Valley; this flow does not intersect any 

current or planned SNWA projects. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(147-14) 

B.2.4.1.9. COMMENT: Several commenters expressed concern about the siting of the 

repository in the unsaturated zone or about the supplement’s description of flow through the 

unsaturated zone to the water table. One commenter referred to the criteria of 1,500 feet of 

overburden and 1,500 feet of underburden to the water table as providing protection above and 

below the repository. Another stated that the repository at Yucca Mountain is the only one in 

the world proposed to be built overlying a water table. Two commenters expressed concerns 

about the potential for fast-flowing water through the unsaturated zone or the potential for the 

upward flow of hot fluids towards the repository. A commenter requested a better description of 

how the radionuclide waste would reach groundwater. 

RESPONSE: The NRC staff acknowledges the comments on the siting of a repository in the 

unsaturated zone, and the importance of flow and transport in unsaturated zone at Yucca 

Mountain for estimating the source term used to calculate potential impacts to the affected 

environment in the supplement. Comments pertaining to the description or capability of the 

unsaturated zone to isolate waste and the potential release of contaminants from the repository, 

however, are outside the scope of the supplement, which concerns an assessment of the 

potential impacts to groundwater and surface discharges of groundwater beyond the 

postclosure compliance location. The scope of this supplement is further described in the 

NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). 

The commenter is correct that, in contrast to the proposed repository at Yucca Mountain, some 

deep geologic repositories for high-level radioactive waste in other countries are proposed to be 

in the saturated zone below the water table. The NRC staff notes that countries that are 

presently investigating deep geologic disposal focus on the geologic conditions existing within 

their borders, and few countries other than the U.S. have extensive regions with a deep (thick) 

unsaturated zone. 
B–64 

DOE analyzed in detail the flow and transport characteristics in the unsaturated zone at 

Yucca Mountain in its Safety Analysis Report (DOE, 2008b, Sections 2.3.2 and 2.3.8). DOE 

also analyzed the chemistry of water reaching the drifts and contacting waste packages in its 

SAR (DOE, 2008b, Section 2.3.5). In addition, DOE considered the likelihood of upwelling fluids 

flooding the repository drifts (SNL, 2008b, FEP 1.2.06.00.OA). The NRC staff review of these 

analyses is given in its SER (NRC, 2014a, Chapters 6, 9, 10, Sections 2.2.1.3.3, 2.2.1.3.6, 

2.2.1.3.7). 

No changes were made to the supplement in response to these comments. 

(020, 041, 086, 095-01, 147-06, 147-25) 

B.2.4.1.10. COMMENT: Several commenters stated that water is a precious and scarce 

resource that must be protected from contamination. Several commenters stated that the risk of 

contamination is unacceptable, and one commenter suggested that the water is being poisoned. 

Several of the commenters voiced concerns about the importance of groundwater in the arid 

area surrounding Yucca Mountain. One commenter stated the need to maintain the purity of 

water for its healing properties. 

Several commenters stated concerns about contamination from the repository, while others 

pointed to existing contamination from the Nevada National Security Site and damage from 

geothermal fields that have already impacted resources and affected public health. 

Commenters stated that aquifers that would be contaminated by the project are irreplaceable, 

some with the same water in them for 100,000 years. Two commenters mentioned the 

interconnectedness of groundwater throughout the region and stated that contaminants migrate 

from one area to another. One commenter stated that the water had to be protected for visitors, 

for people who reside in the area, and for future generations. One commenter questioned the 

credibility of the supplement, considering the importance of water for drinking and other 

groundwater issues. 

RESPONSE: The NRC staff agrees that water is a precious and scarce resource in the region 

and should be protected for use by local populations and visitors and for ecological, agricultural, 

and other purposes. The NRC staff notes that many designed and natural features of the 

repository would act to contain, reduce, and delay the release of waste emplaced in the 

repository, and the NRC staff’s review of these aspects is documented in Volumes 2 and 3 of its 

SER (NRC, 2014a, 2015a). 

Groundwater flow and transport of radionuclides and metals from the repository beyond the 

postclosure compliance location is assessed in the supplement. Many studies have been 

completed over the past decades to help understand the patterns and flow rates of groundwater 

flow in the Death Valley Region (Belcher et al., 2010, and references contained therein). The 

groundwater in the region is interconnected, although the connection between different 

groundwater basins may be weak, indirect, or strong. Based on its knowledge of the 

groundwater flow patterns and characteristics, the NRC staff estimated the direction and extent 

of metal and radioactive contamination that could transport downstream beyond the postclosure 

compliance location to affected environments at discharge locations, such as areas of 

groundwater pumping or natural springs. The NRC staff’s determination in the supplement of 

small impacts in the affected environment is based on a comparison of estimated metal and 

radionuclide concentration and dose with natural background levels and exposures, soil and 

water standards, and other relevant criteria. The NRC staff used many conservative 
B–65 

assumptions in its calculation of impacts in the supplement; several of the more prominent 

conservative assumptions are discussed in Appendix A, Section A.3. These conservative 

assumptions provide the NRC staff with confidence that the impacts to the affected 

environments would be small and likely less than the values estimated. 

The NRC staff agrees that groundwater has been contaminated at the Nevada National Security 

Site (NNSS; formerly, the Nevada Test Site), and that it may potentially reach the affected 

environments associated with a repository at Yucca Mountain. The NRC staff considered 

cumulative impacts in Chapter 4 of the supplement and found them to be small when 

considering sources from the repository and other areas, including those potentially from the 

NNSS groundwater contamination and other sources. 

No changes were made to the supplement as a result of these comments. 

(036, 070, 077, 095-02, 095-11, 095-12, 115, 146-18, 147-16, 147-18, 147-20, 147-27, 149-09, 

149-13) 

B.2.4.1.11. COMMENT: One commenter pointed to a lack of analysis of groundwater 

pumping upgradient of Yucca Mountain, which the comment stated may reduce the 

potentiometric levels in the carbonate aquifer water in the Yucca Mountain area. The 

commenter pointed out that groundwater pumping in basins to the east and northeast of 

Yucca Mountain could reverse vertical gradients between the carbonate aquifer and the 

overlying aquifers below Yucca Mountain, and possibly draw contaminants down into the 

carbonate aquifer, resulting in faster transport to Death Valley. The commenter also stated that 

the draft supplement did not consider the Nevada State Engineer’s ruling in 2005 on the 

SNWA’s right to pump from the lower carbonate aquifer in two hydrographic basins east of 

Yucca Mountain (the Tikapoo and Three Lakes Valley basins). The commenter also noted that 

the Las Vegas Water Authority’s 1989 application also included two other basins northeast of 

Yucca Mountain, two parts of the Railroad Valley. The commenter also suggested that the 

USGS 2014 model be used for modeling potential changes to groundwater conditions in the 

Yucca Mountain region caused by water withdrawal from basins to the east and northeast of 

Yucca Mountain.

RESPONSE: The NRC staff acknowledges the importance to repository performance of 

maintaining the vertical gradient from the carbonate aquifer to the overlying volcanic aquifers 

beneath Yucca Mountain. However, these comments are outside the scope of the supplement, 

which concerns an assessment of the potential impacts to groundwater and surface discharges 

of groundwater beyond the postclosure compliance location, which is 18 km [11 mi] from the 

Yucca Mountain project site. The scope of this supplement is further described in the NRC’s 

Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). Transport of radionuclides from the repository to the postclosure compliance 

location, as part of the performance assessment analyses of the repository, is described in 

Sections 2.3.8 and 2.3.9 in DOE (2008b) and reviewed by NRC staff in the SER 

(2014a, Chapters 10 and 12). 

In the supplement, the NRC staff considered the effect on the groundwater and surface 

discharge areas beyond postclosure the compliance location caused by Nevada State Engineer 

permitted groundwater withdrawals in valleys to the east and northeast of Amargosa Desert. 

These impacts are discussed in Section 2.4 of the supplement. The NRC staff also notes that 

for its analysis, that the State of Nevada Engineer’s order to maintain water levels at Devils Hole 
B–66 

is assumed to remain in force. Any pumping to the east and northeast of Yucca Mountain that 

would affect groundwater conditions in Amargosa Farms and south would also affect 

groundwater levels at Devils Hole, which are the subject of a State of Nevada Engineer order 

(Taylor, 2008). 

The SNWA’s future plans include groundwater pumped from basins in Clark, Lincoln, White 

Pine, and northern Nye County, as summarized in SNWA (2015). The groundwater withdrawals 

from rural areas in eastern Nevada and inter-basin water transfers were one part of SNWA’s 

plans to address estimated future water demands in Las Vegas. For the applications submitted 

in 1989, Nevada State Engineer rulings led to permits being granted for groundwater 

withdrawals and transfers from six basins. Two of the basins are near Las Vegas (Garnet and 

Hidden Valleys). Groundwater withdrawals from the aquifer in these basins are unlikely to affect 

the groundwater levels or vertical gradients beneath Yucca Mountain or along the flow pathway 

to Death Valley due to the significant distance, regional groundwater flow direction to the 

southwest, and relatively weak hydrologic connections perpendicular to that regional flow 

direction (Brooks et al., 2014). The other four basins with granted permits for a total of 

10,600 ac-ft/yr, are Tikapoo2

 Valley (north and south) and Three Lakes Valley (north and south). 

These two valleys are closer to the Yucca Mountain site than Garnet and Hidden Valleys and 

are in Clark and Lincoln Counties, approximately 75 miles northeast and east of Ash Meadows. 

Section 2.4 of the supplement describes modeling results from SNL (2009; comparison of 

Cases 4 and 5) that showed an insignificant effect on groundwater levels and on the vertical 

gradient in the Yucca Mountain or the Amargosa Farms areas caused by groundwater 

withdrawals from the Tikapoo and Three Lakes Valleys. The NRC staff considered the water 

rights permits granted by the Nevada State Engineer as representing reasonably foreseeable 

future actions, and, thus, included the potential effect of these groundwater withdrawals in 

its analysis. 

The commenter provided a report (Zdon and Associates, 2015) that included analysis of the 

effect of groundwater withdrawal at Railroad Valley on the vertical gradients in the saturated 

zone below Yucca Mountain. This analysis used a U.S. Geological Survey regional model 

(Brooks et al., 2014) in steady state (i.e., pumping for a million years) mode with a groundwater 

withdrawal rate derived from the 1989 applications for Railroad Valley. Under these conditions, 

large drawdowns were predicted to occur across the entire NNSS and extending to 

Yucca Mountain and Ash Meadows. The authors acknowledge the limitations of the model, 

particularly because of large simulated drawdowns {>610m [2000 ft]} for the steady-state 

pumping case, but maintains that the concept warrants further analysis in the supplement. The 

NRC staff, however, considers the Railroad Valley (north and south parts) groundwater 

withdrawal plan speculative and not reasonably foreseeable, because (i) the 1989 applications 

have lapsed and must be resubmitted (SCN, 2010); (ii) if the applications are resubmitted, a 

Nevada State Engineer’s ruling is needed for a permit to be granted; (iii) the amount of 

groundwater withdrawal in the application may change from the 1989 application; and 

(iv) SNWA has not advanced the application, and states that they intend to pursue the Railroad 

Valley development “when needed to supply future demands” (SNWA, 2015). Therefore, 

analysis of the effects of potential withdrawals from Railroad Valley is not included in the 

supplement. 

 

2

Also referred to as Tikaboo Valley 
B–67 

For the group of Delamar, Dry Lake, Cave, and Spring Valleys in eastern Nevada, SNWA 

resubmitted applications in 2011 for these water rights, and the BLM completed an 

environmental impact statement (BLM, 2012c) analyzing impacts of the groundwater withdrawal 

and inter-basin water transfer project. The Nevada State Engineer ruled on the applications in 

2012, but ongoing litigation has delayed issuance of the permits (SNWA, 2015). Modeling 

results of groundwater withdrawals in the BLM EIS (BLM, 2012c) indicate that these proposed 

withdrawals would not cause significant impacts to the groundwater system at Ash Meadows, 

Amargosa Valley, or beneath Yucca Mountain. This inter-basin transfer water project is also 

discussed in Section B.2.5.7. 

With regard to the model recommended by the commenter, the NRC staff is aware of the recent 

and ongoing development of the U.S. Geological Survey (USGS) regional flow model (Brooks et 

al., 2014). This model covers the Great Basin carbonate and alluvial aquifer system extending 

from California to Idaho, including large portions of Nevada and Utah. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

The NRC staff revised the discussion in Section 2.4 (subsection titled Effects of Pumping on 

Groundwater Conditions) in response to these comments. The discussion pertaining to the 

impacts of the planned Southern Nevada Water Authority groundwater withdrawals in eastern 

Nevada now specifically refers to the Tikapoo and Three Lakes Valleys. 

(142) 

B.2.4.1.12. COMMENT: Several commenters stated that groundwater would be 

contaminated because the repository would be incapable of isolating the waste. Many of those 

commenters stated that there would be significant releases over the course of one million years, 

stating that significant impacts would occur over a broad region downstream and affect existing 

and potential new water users in Amargosa Valley, the Ash Meadows National Wildlife Refuge, 

and Death Valley. Other commenters stated that the draft supplement conflicts with the Blue 

Ribbon Commission’s assessment of geologic repositories; that the NRC staff’s predictions 

have no credibility over a one-million-year period; that water is scarce in the region; and that 

groundwater has already been contaminated by Nevada National Security Site operations. One 

commenter suggested that the probability of discharges of pollutants into the groundwater 

raises issues with respect to the Nevada Water Code and the Nevada Water Pollution 

Control Law. 

RESPONSE: The NRC staff acknowledges the concerns expressed by the commenters about 

potential radionuclide releases from Yucca Mountain and the magnitude of associated impacts 

over the course of a million years. Section B.2.2.1 of this appendix addresses commenters’ 

concerns about the long timeframe under consideration in this supplement. Comments 

concerning the potential for leakage from the repository and transport of radionuclides to the 

compliance location are outside the scope of the supplement, which concerns an assessment of 

the potential impacts to groundwater and from surface discharges of groundwater beyond the 

postclosure compliance location. The scope of the supplement is further described in the 

NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). 
B–68 

Also out of scope for this supplement are comments concerning releases from the repository to 

the groundwater that commenters believe would violate the Nevada Water Code and the 

Nevada Water Pollution Control Law. This is also further discussed in Section B.2.1.2.12. DOE 

provided discussions in Chapter 11 of the 2002 and 2008 EISs regarding compliance with 

Federal and State statutes for discharge. 

The NRC staff estimated in the supplement that radioactive contamination would spread 

downstream beyond the postclosure compliance location to affected environments at potential 

discharge locations, such as areas of groundwater pumping or natural springs. The NRC staff’s 

determination of small impacts in the supplement is based on a comparison of estimated 

radionuclide concentration and dose with natural background levels and exposures, soil and 

water standards, and other recommended criteria. For example, as the estimated dose from 

releases from the repository (e.g., 0.21 and 1.3 mrem/yr at Amargosa Farms at 10,000 and 

million years, respectively) is a small fraction of the natural background radiation exposure 

(300 mrem/yr), the NRC staff concluded that the impact would be small. In addition, the 

estimated dose from repository releases is much less than the NRC dose standards for a 

Yucca Mountain repository in 10 CFR Part 63 {15 mrem/yr [0.15 mSv/yr] for the first 

10,000 years, and 100 mrem/yr [1 mSv/yr] for one million years after permanent closure}. 

The NRC staff disagrees with the comment that the supplement conflicts with the Blue Ribbon 

Commission (BRC, 2012) assessment of geologic repositories. The BRC was explicitly directed 

not to serve as a siting body, nor to evaluate Yucca Mountain or any other location as a 

potential site for the storage of spent nuclear fuel or disposal of high-level waste. Nor did the 

BRC take a position on the Administration’s request to withdraw the Yucca Mountain license 

application. The BRC (2012) endeavored to recommend a sound waste management approach 

for disposal of spent nuclear fuel and other high-level nuclear wastes that “neither includes nor 

excludes Yucca Mountain as an option for a repository and can and should be applied 

regardless of what site or sites are ultimately chosen to serve as the permanent 

disposal facility.” 

The NRC staff agrees that groundwater has been contaminated at the Nevada National Security 

Site (NNSS; formerly, the Nevada Test Site), and that it may potentially reach the affected 

environments for the repository. The NRC staff considered cumulative impacts in Chapter 4 of 

the supplement and found these impacts to be small when considering sources from the 

repository and other areas, including the NNSS. 

No changes were made to the supplement as a result of these comments. 

(002, 003, 004, 008, 010, 011, 013, 014, 015, 022, 023, 028, 031, 039, 040, 043, 047, 048, 053, 

054, 055, 057, 064, 066, 070, 071, 075, 076, 078, 079, 082, 083, 085, 092, 093, 094, 096, 101, 

104, 112, 139, 146-07, 147-23, 148) 

B.2.4.1.13. COMMENT: Several commenters expressed concern regarding water leaking 

into and out of the potential repository at Yucca Mountain. One commenter stated that activities 

at the Nevada National Security Site are causing contamination in area groundwater, and asked 

whether contaminated groundwater would be decontaminated. Another comment referred to 

previous analyses on water flow through fractured rocks around Yucca Mountain and the 

relationship between the observed travel time of water through the rock and the travel times 

allowed for in guidelines that were eventually eliminated. 
B–69 

RESPONSE: The NRC staff acknowledges the concerns expressed by the commenters about 

groundwater contamination and flow around the repository, both from the proposed repository 

and from other activities at the NNSS. These comments are outside the scope of the 

supplement, which concerns an assessment of the potential impacts to groundwater and 

surface discharges of groundwater beyond the postclosure compliance location, which is 18 km 

[11 mi] from the Yucca Mountain project site. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 

The NRC staff’s evaluation of information on groundwater flow into and around the proposed 

repository is contained in Volume 3 of the staff’s SER for the Yucca Mountain repository license 

application (NRC, 2014a, Chapters 6 and 9 through 12) and in the staff’s ADR for the EISs 

prepared by DOE for the proposed repository. These documents are available on the NRC’s 

Web site at http://www.nrc.gov/waste/hlw-disposal/key-documents.html. 

No changes were made to the supplement as a result of these comments.

(080-03, 088, 108, 122, 147-19) 

B.2.4.2 Public and Occupational Health 

B.2.4.2.1. COMMENT: Several commenters expressed general concerns about radiation 

and the health risks associated with exposure to radiation. One commenter asserted gamma 

radiation is not contained by structures, and that materials like rock, concrete, salt, or metal 

degrade with exposure to radiation. The commenter stated that future generations will be 

exposed to released radiation. Another noted that despite the draft supplement’s conclusion 

that radioactive material releases from the repository would be small, there is no safe dose of 

radiation. 

Another commenter referenced a New York Times article from 1989 that suggested the National 

Academy of Sciences had stated in 1983 that because of the chemical characteristics of the 

water at Yucca Mountain, the waste would dissolve more easily there than at most other places. 

The commenter further stated that DOE scientists know that the steel waste canisters would 

dissolve long before the radiation hazards are gone. 

RESPONSE: The dose limits for the proposed repository were set by the EPA as required by 

the NWPA, considering recommendations from the National Academy of Sciences and national 

and international standards-setting organizations, such as the International Commission on 

Radiological Protection (ICRP), National Council on Radiation Protection and Measurements 

(NCRP), and International Atomic Energy Agency (IAEA). The ICRP’s and NCRP’s 

recommendations are developed by recognized experts in the fields of radiation protection and 

health effects, including representatives from the NRC. In describing the final rule for 10 CFR 

Part 63, the NRC expressed confidence that the EPA’s 0.15 mSv/yr [15 mrem/yr] limit is fully 

protective and that it provides an added margin of safety beyond what is necessary to ensure 

public health and safety (66 FR 55732). The radiation impacts identified in the supplement are 

also a small fraction of the average annual background radiation exposure received by the 

public each year in the U.S. from natural sources {3.1 mSv [310 mrem]} and all sources 

{6.2 mSv [620 mrem]} (NRC, 2015c). 
B–70 

One commenter asserted there is no safe dose of radiation. Although very small risks of health 

effects can be estimated from low doses of radiation, the NRC staff considers that doses within 

NRC limits are protective of public safety. 

Section 3.1 of the supplement provides additional information about the NRC staff’s bases and 

conservative approach for evaluating the potential health effects from exposure to low doses of 

radiation from the proposed repository. 

A number of commenters raised concerns related to the NRC staff’s use of information from 

DOE’s TSPA, which was part of DOE’s license application for the proposed repository at 

Yucca Mountain, as a primary input and as support for evaluating environmental impacts in this 

supplemental EIS. A discussion of the use of modeling in the supplement can be found in 

Sections 1.2.2 and 2.4, B.2.2.2, and Appendix A of the supplement. 

The NRC staff’s evaluation of these topics, as presented in the license application, is contained 

in the staff’s SER for the Yucca Mountain repository license application (NRC, 2014a). 

Additional information on the relationship among the supplement’s assumptions and approach 

and the TSPA can be found in Section B.2.2.2. 

As stated in Section 3.1 of the supplement, the NRC staff found DOE’s TSPA methodology to 

be acceptable as part of its safety evaluation (NRC, 2014a, Section 2.2.1.4.1). Additionally, in 

the ADR, the NRC staff identified only the DOE’s evaluation of impacts downgradient of the 

postclosure compliance location as an area where supplementation is needed. 

No changes were made to the supplement in response to these comments. 

(025, 066, 076, 086) 

B.2.4.2.2. COMMENT: A commenter asked if the calculations in the draft supplement 

considered a catastrophic event occurring underground.

RESPONSE: Comments concerning the potential occurrence of an underground catastrophic 

event are beyond the scope of this supplement, which concerns an assessment of the potential 

impacts to groundwater and surface discharges of groundwater beyond the postclosure 

compliance location, which is 18 km [11 mi] from the Yucca Mountain project site. The scope of 

this supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

As described in Appendix A of the supplement, the analytical framework used by the NRC staff 

extends the framework that DOE used for the analyses in its 2002 and 2008 EISs (DOE, 2008a; 

2002) and license application (DOE, 2008b). In the 2008 SEIS, DOE used results from the 

TSPA model to estimate the source term for radionuclides and transport to the postclosure 

compliance location. Section B.2.2.2 further discusses the staff’s use of information from the 

TSPA to inform the analyses in this supplement. 

No changes were made to the supplement in response to this comment. 

(095-08) 

B.2.4.2.3. COMMENT: Several commenters expressed concerns about the 

representativeness of draft supplement dose calculations and, in particular, the modeled routes 
B–71 

of exposure to Native American peoples and other groups (i.e., exposure pathways). One 

commenter suggested that the draft supplement does not explain risks using a culturally 

appropriate context, inappropriately applies the “reasonably maximally exposed individual” 

(RMEI) modeling concept to Native Americans, and does not assess the cumulative risk to 

Native Americans living in the community. Other commenters stated that the environmental 

radiation protection standards for Yucca Mountain are not protective of the Newe Sogobia, and 

that their exposure would be significantly higher because of lifestyle differences, including 

religious practices, tribal laws, customs, and traditions. Another commenter suggested the 

public health impacts that could affect the Timbisha Shoshone people were not fully examined 

in the supplement, as required by NEPA, because the NRC staff had not evaluated the 

ingestion of crops, animal products, and fish as pathways for exposure in the Furnace Creek 

area (citing page 3-37 of the draft supplement). Another commenter noted that the traditional 

lifestyle of the Western Shoshone Indians has been in practice for thousands of years in the 

Yucca Mountain region, and includes hunting and gathering and the use of spring water for 

drinking. The commenter stated that this drinking water is being threatened by the proposed 

repository and disagreed with the 11-mile downgradient compliance location. 

Another commenter stated that the public health impact conclusions in Chapter 5 of the draft 

supplement do not account for potential exposures (and protective protocols) to archaeologists, 

material culture experts, material scientists, conservators, and traditional artisans who extract 

materials from affected discharge areas. The commenter stated that these potential health 

consequences should be included in estimates of potential health impacts and further explored 

through tribal and public consultation. Another commenter wanted to know if the milk ingestion 

pathway is addressed in the dose calculations in the draft supplement. 

RESPONSE: The public health impact analyses in the supplement broadly apply to any 

individuals in the region, including Native Americans. The NRC staff’s analyses included 

several conservative assumptions, including regarding the use of groundwater for agricultural 

and domestic use, use of stream water for drinking, fishing, and exposure to the ground surface 

(Sections 3.1 and 3.4 and Appendix A, Section A.2.3). Additionally, the supplement evaluates 

environmental justice impacts and cumulative environmental justice impacts to the Timbisha 

Shoshone Tribe community in the Furnace Creek area in Sections 3.4.2 and 4.5.2.3. 

Additional information about the NRC’s radiation safety regulations can be found in 

Section B.2.4.2.1. Comments about the appropriateness and protectiveness of the NRC’s 

regulations, the postclosure compliance location, and any other aspects of Yucca Mountain 

standards are beyond the scope of this analysis. 

No changes were made to the supplement in response to these comments. 

(024, 043, 046, 060, 080-16, 131, 136, 147-10, 148) 

B.2.4.2.4. COMMENT: A few commenters expressed concerns about the description of 

dose results in the draft supplement. One commenter (citing page 3-14, lines 4-8, and page 

3-20, lines 12-14) stated the impacts to the public are small and insignificant and requested the 

NRC compare the results to background radiation. The commenter also cited page 3-25, lines 

31-36 and requested that the NRC report the peak dose, noting that the supplement text 

indicates the peak dose is lower than the regulatory standard, while Table 3-11 indicates the 

peak dose is less than 1 mrem/yr. Another commenter expressed the view that an independent 

review of the modeling in the draft supplement (Bredehoeft and King, 2015) determined the 
B–72 

radionuclide transport and dose modeling results in the draft supplement for the Death Valley 

Furnace Creek and lower section of Amargosa Valley areas are small and within EPA health 

standards. 

RESPONSE: The information the commenters requested concerning calculated dose results in 

the context of background radiation is included in the supplement. Specifically, the supplement 

compares potential dose impacts to background dose in the paragraphs preceding the results in 

the two sections highlighted by the commenter. Peak dose values are provided in Table 3-11, 

which is referenced in Section 3.1.2.2 of the supplement. The NRC staff agrees with the 

commenters that stated the dose results are small, insignificant, and below EPA standards. 

No changes were made to the supplement in response to these comments. 

(046, 142) 

B.2.4.2.5. COMMENT: One commenter claimed the process of radiation health risk 

estimation used in the draft supplement is an oversimplification and is incorrect. The 

commenter drew a comparison between how chemicals and radionuclides affect human health. 

The NRC staff interprets the comment as suggesting that the NRC assumption that health risks 

from exposure to low doses of radiation are correlated with dose is a misapplication of principles 

that only apply to chemical toxicology. The commenter suggested that only chemicals have 

toxic thresholds and radiation does not, and that there is no safe radiation dose. The 

commenter concluded that the effects of dilution during transport from the repository to 

downgradient locations cannot be considered as a means of reducing the radiological impacts. 

Another commenter was concerned that the radiation health risk data used in the draft 

supplement was based only on one or two generations of health studies rather than the 

thousands of generations they asserted would be needed to address long-term genetic effects 

on exposed populations. The comment was expressed in the context of a broader concern that 

data from the Fukushima accident in Japan was not being used to update Yucca Mountain 

calculations. The commenter suggested, for example, that new information from Fukushima 

about the flammability of spent fuel cladding should also be incorporated into Yucca Mountain 

calculations. 

RESPONSE: The NRC approach to estimating health risks from radiation conservatively 

assumes no threshold for effects, which is consistent with the recommendations of national and 

international standards-setting organizations, such as the ICRP and the NCRP. The ICRP’s 

and NCRP’s recommendations are developed by recognized experts in the fields of radiation 

protection and health effects, including representatives from the NRC. 

The radiation protection community conservatively assumes that any amount of radiation may 

pose some risk for causing cancer and hereditary effect, and that the risk is higher for higher 

radiation exposures. The linear, no-threshold, dose-response relationship is used to describe 

the relationship between radiation dose and the occurrence of cancer. This dose-response 

model suggests that any increase in dose, no matter how small, results in an incremental 

increase in risk. The NRC accepts the linear, no-threshold hypothesis as a conservative model 

for estimating radiation risk. For additional information about radiation safety and NRC 

regulations, see Section B.2.4.2.1. 

Concerns about spent fuel cladding performance estimates based on data from the Fukushima 

accident is beyond the scope of this supplement, which concerns an assessment of the 
B–73 

potential impacts of repository releases to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(095-02, 146-15) 

B.2.4.2.6. COMMENT: A few commenters noted the draft supplement does not account 

for increased cancer incidence. One commenter added that the Environmental Protection 

Agency standards would limit the site’s release of radiation to levels that will cause no more 

than 1,000 cancer deaths over 10,000 years. Another commenter asserted the supplement was 

not based on current science. They cited a study that they claimed showed an association 

between long-term low-dose radiation exposure and leukemia mortality and asserted the 

conclusions in the supplement that the low calculated doses result in a negligible increase in 

cancer risk was incorrect and misleading. 

RESPONSE: As noted in the supplement, the calculated annual doses are very low, consistent 

with the limits in 10 CFR Part 63, and are protective of human health and the environment. The 

summary of impacts in Chapter 5 of the supplement provides that the NRC staff expects that the 

estimated radiation dose from the proposed repository would contribute only a negligible 

increase in the risk of cancer or severe hereditary effects to the potentially exposed population. 

Additional information about the NRC’s radiation protection standards and the scientific bases 

for evaluating health risks from exposure to radiation can be found in Section B.2.4.2.1. 

No changes to the supplement were made in response to this comment. 

(046, 086)

B.2.4.2.7. COMMENT: A commenter cited newspaper articles describing previous studies 

that proposed alternative hypotheses of long-term repository performance resulting in large 

releases of radioactive materials. This included a 1995 hypothesis by a Los Alamos National 

Laboratory physicist that suggested wastes might erupt in a nuclear explosion. The commenter 

also referred to Charles Bowman and Francesco Venneri, who suggested failure of waste 

containers in the future will cause plutonium to disperse into surrounding rock. Additionally, the 

commenter mentioned former DOE geologist Jerry Szymanski, who suggested that catastrophic 

events are possible that would be greater than Chernobyl. 

RESPONSE: Long-term repository performance is beyond the scope of this supplement, which 

concerns an assessment of the potential impacts of repository releases to groundwater and 

surface discharges of groundwater beyond the postclosure compliance location, which is 18 km 

[11 mi] from the Yucca Mountain project site. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 
B–74 

Additional information documenting the NRC staff’s review of the DOE’s TSPA, including the 

potential for disruptive events, is provided in the staff’s SER (NRC, 2014a,b; 2015a,c). 

No changes were made to the supplement in response to this comment.

(086) 

B.2.4.2.8. COMMENT: A commenter suggested the magnitude of the repository inventory 

of nonradiological constituents presents a potential health risk that should be investigated 

further. The commenter asserted the DOE groundwater analysis (DOE, 2009a) of 

nonradiological constituents that is referenced in the draft supplement contains errors. The 

commenter referred to Figure 1 of that report, which depicts the daily intakes of nonradiological 

contaminants at the Armargosa Farms area for the present climate. Describing chromium as a 

potent carcinogen, the commenter requested a basis for excluding chromium and vanadium 

from the daily intake calculations. The commenter stated that about 43,300 tons of chromium 

would be disposed of in the repository (citing the 2002 DOE EIS) and added that no data were 

provided for the area near the repository. The commenter also wanted to know whether the 

sorption of zeolite assumed in the calculations followed the order in which light elements replace 

heavy elements. The commenter also suggested the cited DOE report lacks credible evidence 

to support the DOE and NRC draft supplement conclusions that the impact of nonradiological 

elements on the human and groundwater environment would be minimal.

RESPONSE: The NRC staff disagrees with the commenter that its chromium and vanadium 

analyses need to be revised or corrected. In Appendix A of the draft supplement, the NRC staff 

summarizes the NRC staff’s basis for excluding chromium from the analysis. In the 2002 EIS, 

the chemicals of concern resulting from the DOE screening analysis were chromium (Cr), 

molybdenum (Mo), nickel (Ni), and vanadium (V). In the 2008 EIS, DOE screened out Cr on the 

basis that the expected predominant form would be Cr (III) (chromium in a valance state of +3) 

in the repository environment, which is nontoxic to humans and relatively insoluble; that is, 

significant levels would not be dissolved in water, and thus would not migrate into the 

groundwater. DOE found that the more toxic form, Cr (VI), would not form by corrosion of the 

waste package material (Alloy 22) or stainless steel under repository conditions (2008 EIS, 

Section F-5.1). If Cr (VI) forms from such corrosion in the repository, the DOE screening 

analysis in the 2008 EIS found that Cr (VI) is efficiently and quickly reduced to Cr (III) (Eary and 

Rai, 1989; Palmer and Puls, 1994) in the expected repository environment. The NRC staff, in 

its safety evaluation, found the DOE description of the repository chemical environment to be 

acceptable (NRC, 2014a; Section 2.2.1.3.3). 

Regarding the commenter’s question about how sorption was evaluated in the DOE’s transport 

modeling, the DOE report (DOE, 2014) describes the technical bases for selection of distribution 

coefficients for radiological and nonradiological constituents, and uses distribution coefficients 

that reasonably represent radiological and nonradiological constituent retention on the 

composite material of the aquifer matrix. Additional information can be found in DOE, 2014 and 

in the supplement description of the transport model in Appendix A, Section A.1.2. 

Potential impacts of nonradiological releases in the immediate vicinity of the repository is 

beyond the scope of the supplement, which concerns an assessment of the potential impacts of 

repository releases to groundwater and surface discharges of groundwater beyond the 

postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain project site. 
B–75 

No changes were made to the supplement in response to these comments. 

(116) 

B.2.4.2.9. COMMENT: A commenter recommended the NRC provide carcinogenic risk 

coefficients for the receptors evaluated in the draft supplement based on EPA Federal Guidance 

Report No. 13 (EPA, 1999d), noting that the Interagency Steering Committee on Radiation 

Standards recommends the use of these radionuclide-specific risk coefficients. 

RESPONSE: The NRC staff’s risk estimates in Sections 3.1, 3.5, and Chapter 5 of the 

supplement are based on the conversion factor for members of the public recommended by the 

International Committee on Radiological Protection (ICRP, 2007) that estimates the probability 

of a latent cancer fatality, nonfatal cancer, or severe hereditary effects from a 1.0 mrem/yr 

[0.01 mSv/yr] dose as 5.7 × 10−7

, or less than one in one million. Although the NRC staff 

considers both sources of risk factors appropriate, the health risk from the low mrem-level 

radiation dose calculated in the supplement is negligible for either reference. 

No changes were made to the supplement in response to the comment. 

(137) 

B.2.4.2.10. COMMENT: A commenter suggested that age and sex differences be 

addressed in radiation dosimetry because girls and women are between seven and two times 

more vulnerable than the standard man model used by Federal agencies to calculate radiation 

dose. The commenter suggested that the appropriate level of protection is subject to 

reevaluation and change. 

RESPONSE: While the NRC staff agrees that different individuals may have different 

radiosensitivity, the NRC’s radiation protection standards for Yucca Mountain in 10 CFR Part 63 

and 10 CFR Part 20 are protective of public health and include significant conservatism. This 

issue was addressed in detail in the development of the NRC standards for YM (66 FR 55732). 

Additional information about NRC radiation protection programs can be found in Section 

B.2.4.2.1. 

No changes were made to the supplement in response to the comment. 

(146-02)

B.2.4.3 Ecological Resources 

B.2.4.3.1. COMMENT: The NRC received several general comments about the diverse 

and unique wildlife species found in the potential surface discharge areas evaluated in the draft 

supplement. These commenters expressed concerns regarding radiation impacts and 

contaminated groundwater affecting wildlife. Other commenters expressed concern about 

potential impacts on the endangered pupfish at Devils Hole and Ash Meadows.

RESPONSE: The potential radiological and chemical constituent effects on people and the 

environment from impacted soil, water, and ecology at discharge locations are evaluated in the 

supplement. The NRC staff’s determination of small impacts on ecological resources in the 

supplement is based on a comparison of estimated chemical constituents and radionuclide 

concentrations and dose with natural background levels and exposures, soil and water 
B–76 

standards, and other applicable standards. As discussed in the supplement, the Nevada State 

Engineer is responsible for limiting groundwater withdrawal in the Ash Meadows area that may 

impact Devils Hole and the endangered Devils Hole pupfish. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified related to ecological concerns that requires 

further supplementation of DOE’s 2002 and 2008 EISs in the future. The completion of 

licensing activities, however, is subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(025, 095-12, 147-20, 147-21, 149-12) 

B.2.4.3.2. COMMENT: One commenter stated that the draft supplement does not include 

an adequate analysis on impacts to endangered species in Ash Meadows, and suggested that 

NRC should determine the toxicity of the interaction between mixtures of metals and 

radionuclides on the pupfish at Ash Meadows. 

RESPONSE: The NRC staff acknowledges that the supplement does not evaluate potential 

impacts on endangered species listed under the Endangered Species Act (ESA) in the Ash 

Meadows area. As stated in Section 2.3.3 of the supplement (subsection titled Ash Meadows), 

Ash Meadows is not a discharge location for groundwater flowing from Yucca Mountain. The 

source of water to the springs at Ash Meadows is the regional carbonate aquifer, which is fed by 

recharge from the Spring Mountains, which flows from the east and northeast towards Ash 

Meadows. Therefore, impacts to endangered species in Ash Meadows are outside the scope of 

this supplement, which concerns an assessment of the potential impacts to groundwater and 

surface discharges of groundwater beyond the postclosure compliance location. The scope of 

this supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified related to ecological resources that requires 

further supplementation of DOE’s 2002 and 2008 EISs in the future, including evaluation of 

potential impacts to sensitive or endangered species. The completion of licensing activities is 

subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(116) 

B.2.4.3.3. COMMENT: Two commenters stated that the draft supplement does not include 

an adequate analysis or consultation for threatened and endangered species that could exist at 

the discharge locations, including the Amargosa Vole and least Bell’s vireo. One commenter 

stated that NRC is required to consult with the U.S. Fish and Wildlife Service under Section 7 of 

the Endangered Species Act regarding potential impacts to threatened and endangered species 

that may be found at groundwater discharge locations evaluated in the draft supplement. The 

same commenter also suggested that NRC determine whether potential dose-related impacts 

on those species could occur at an individual, population, or community level. 
B–77 

RESPONSE: The NRC staff acknowledges that the supplement does not evaluate potential 

impacts on specific species at discharge locations that may be listed under the Endangered 

Species Act (ESA). As noted in Section 4.2 of the staff’s ADR, DOE stated that it is the lead 

agency for consulting with the U.S. Fish and Wildlife Service under Section 7 of the ESA. The 

NRC staff recognizes that the discharge areas assessed in this supplement are not addressed 

in the biological opinion reflecting DOE’s prior Section 7 consultations. 

The potential radiological and chemical constituent effects on people and the environment from 

impacted soil, water, and ecology at discharge locations are evaluated in the supplement. The 

NRC staff’s determination of small impacts on ecological resources in the supplement is based 

on a comparison of estimated chemical constituents and radionuclide concentration and dose 

with natural background levels and exposures, soil and water standards, and other 

recommended criteria. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified related to ecological resources that requires 

further supplementation of DOE’s 2002 and 2008 EISs in the future, potentially including 

impacts to sensitive or endangered species. The completion of licensing activities, however, is 

subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement in response to these comments.

(134, 142, 148, 149-10) 

B.2.4.4 Historic and Cultural Resources 

B.2.4.4.1. COMMENT: The NRC received comments expressing opposition to the 

proposed repository at Yucca Mountain, stressing its impacts to cultural and historic resources. 

Several commenters stated that NRC did not adequately consider the cultural and spiritual 

values associated with groundwater and springs in the discharge locations and their 

contamination. One commenter lists impacts to living tribal lifeways; to freedom of religion and 

beliefs, tribal spiritual properties; to a shared sense of community; and to physical effects on 

medicinal plants, minerals, and water as among the potential impacts of the proposed 

repository. Some of the commenters stated that even perceived impacts on ground and surface 

water at discharge locations can affect the cultural healing properties of the water. One 

commenter provided examples of groundwater discharge locations that are culturally sensitive 

areas to the Timbisha Shoshone Tribe, and explained that those and other cultural and historic 

resources would be negatively impacted by the proposed repository. The same commenter 

suggested that additional studies are needed to comprehensively delineate the tribe’s cultural 

and historic interests that could be impacted by the project. Another commenter stated that 

going forward with the project would be disrespectful to the Native American community. 

Another commenter suggested the NRC should consider potential effects from radioactive and 

nonradioactive materials on a variety of cultural resources in the soils that are found at either 

the pumping locations or water discharge locations. The commenter stated that NRC has not 

considered the attributes that afford a historic property its significance and integrity of location 

(e.g., design, setting, materials, workmanship, feeling, and association), including the perception 

of the Native American community that these locations are being spiritually tainted by the 

introduction of such materials. 
B–78 

RESPONSE: The NRC staff acknowledges the concerns expressed by many commenters 

about Native American perspectives and values associated with groundwater and springs, and 

potential impacts to cultural resources at discharge locations. Radiological and nonradiological 

effects on people and the environment from impacted soil, water, and ecological resources at 

discharge locations, including plants and water that could be used for cultural purposes, are 

evaluated in the supplement. 

Section 2.3.2 of the supplement recognizes that cultural and historic resources may be located 

in the vicinity of discharge areas. Section 3.3 of the supplement describes DOE’s activities 

related to tribal consultations and cultural and historic resources under the National Historic 

Preservation Act (NHPA) and its Native American Interaction Program. The NWPA identifies 

DOE as the lead agency responsible for these activities. The NRC staff also notes the 

commitment DOE made in its EISs to complete these activities for impacted areas within the 

scope of the proposed repository. The supplement also describes DOE’s programmatic 

agreement with the Advisory Council on Historic Preservation and the Nevada State Historic 

Preservation Office. The NRC staff’s supplement addresses groundwater discharge areas that 

are not addressed in DOE’s EISs or in the executed programmatic agreement. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified related to cultural resources and other 

Native American concerns that requires further supplementation of DOE’s 2002 and 2008 EISs 

and the continuation of tribal consultations in the future. The completion of licensing activities, 

however, is subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(024, 036, 048, 060, 061, 070, 095-05, 095-11, 122, 131, 136, 146-07, 147-10, 147-20, 147-22) 

B.2.4.4.2. COMMENT: One commenter stated that NRC has not listened to the comments 

of the Native American community or addressed those concerns, including cumulative impacts. 

The commenter disagreed with the NRC staff’s assessment of health effects from 

Yucca Mountain on the basis that the assumptions used in the TSPA model are flawed, and 

pointed out that the supplement does not consider spiritual and philosophical aspects of Native 

American cultural values. The commenter expressed that the Timbisha Shoshone Tribe is an 

affected tribe under the NWPA. The commenter further stated that the supplement does not 

address the major cultural, environmental, and health harm described by individual members of 

the Native American community that live in the affected area, including Western Shoshone and 

Southern Paiute people. The same commenter stated that the supplement failed to provide a 

map showing the groundwater discharges on Native American cultural and spiritual resources in 

the affected area under the no-pumping scenario. The commenter provided a copy of such a 

map in relation to both tribal lands and springs. 

RESPONSE: The NRC staff acknowledges the concerns expressed about radiation, the health 

risks associated with exposure to radiation, and the Native American perspective regarding 

cultural values of the groundwater and springs in the area of discharge locations. The NRC 

staff also acknowledges the Timbisha Shoshone’s affected tribe status. The development of 

this supplement is one of several steps in the licensing process for the proposed repository. 

Information may be identified related to cultural resources and other Native American concerns 

that requires further supplementation of DOE’s 2002 and 2008 EISs in the future. However, the 

completion of licensing activities is subject to appropriations and other actions external to 

the NRC. 
B–79 

Regarding the assumptions used in the TSPA model, Section B.2.2.2 of this appendix

addresses comments on the TSPA model. 

The NRC staff reviewed the map of tribal lands and springs that one commenter provided. In 

response to this comment, the NRC staff has added a new Figure 2-6 to Section 2.6 of the 

supplement. This figure shows the groundwater flow paths for the pumping and no-pumping 

scenarios, as indicated by particle tracking. 

(148) 

B.2.4.5 Environmental Justice 

B.2.4.5.1. COMMENT: Commenters stated that the potential for disproportionate impacts 

on minority or low-income populations from the Yucca Mountain project, especially members of 

the Timbisha Shoshone and Western Shoshone, is high due to current and traditional lifestyles. 

One commenter added that the rights and welfare of indigenous people must be respected 

and addressed. 

RESPONSE: The NRC staff acknowledges the commenters’ concerns about the potential for 

disproportionate impacts on certain communities. Section 3.4.2 of the supplement assesses the 

potential human health and environmental effects that contaminated groundwater from the 

repository could have on minority and low-income populations. The staff determined that a 

repository at Yucca Mountain would not affect minority or low-income populations 

disproportionately, including impacts on historic and cultural resources. 

The NRC staff recognizes that Native Americans use water for its spiritual, healing, and other 

qualities, and that many Native Americans believe that any impact to the water harms these 

qualities. Section 3.2.1.4.3 of the NRC staff’s ADR notes that DOE committed to continue to 

work with tribes to identify mitigation measures to address tribal perspectives. The preparation 

of this supplement is one of several steps in the licensing process for the proposed repository. 

Information may be identified that requires further supplementation of DOE’s 2002 and 2008 

EISs in the future. The completion of licensing activities is subject to appropriations and other 

actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(002, 003, 004, 008, 013, 014, 022, 028, 031, 036, 039, 040, 047, 048, 053, 054, 055, 057, 071, 

075, 076, 078, 079, 082, 083, 085, 092, 093, 094, 101, 104, 111, 112, 131, 139, 146-07) 

B.2.4.5.2. COMMENT: The NRC received several comments disagreeing with the NRC 

staff’s environmental justice analysis. One commenter stated that NRC has failed to fully 

consult with the Timbisha Shoshone Tribe and meaningfully identify and consider the 

Timbisha’s cultural and historic resources, which is further discussed in Sections B.2.1.2.10 and 

B.2.4.4. Other commenters expressed similar sentiments, stating that the NRC did not include 

in the supplement an adequate environmental justice consideration of the community of Tecopa, 

of Native American cultural and historic resources, and of the special meaning that water has for 

the tribes. One commenter stated that the inadequate funding, notice, and time provided to 

comment on the draft supplement also constitutes an environmental justice issue. 

RESPONSE: The NRC staff assessed the potential human health and environmental effects on 

minority and low-income populations in accordance with NRC environmental justice guidance. 
B–80 

The NRC staff evaluated potential impacts that may be unique to minority, low-income, and 

Native American communities. As the NRC staff explained in Section 3.3.5 of the supplement, 

the surface discharge locations considered in this supplement are outside the region of 

influence that DOE assessed in its EISs and in its programmatic agreement to address impacts 

on known cultural and historical resources and unanticipated finds under the National Historic 

Preservation Act. As also noted in the supplement in Section 3.3.2, consultation under the 

NHPA is not complete. 

The NRC staff acknowledges commenters’ concerns about the amount of notice commenters 

received before the draft supplement was published and the time provided to review the 

document. In March 2015, the NRC staff announced in the Federal Register its intent to 

develop the supplement. The NRC staff also provided this information via email in March to 

persons and organizations on the adjudicatory distribution list in the Yucca Mountain licensing 

proceeding, members of the Timbisha Shoshone Tribe, and other interested stakeholders. On 

August 13, 2015, the NRC staff advised stakeholders that the draft supplement was available 

for review and provided a link to the supplement on the NRC’s public Web site. The NRC’s 

public Web site also provided information about upcoming public meetings, which gave the 

public opportunities to provide oral comments on the supplement. The NRC staff also held a an 

initial, informational public meeting via a teleconference on August 26, 2015. At the August 26 

meeting, the NRC staff explained how the public comment process works and responded to 

stakeholders’ questions about the process. In response to requests from the public, the NRC 

staff extended the public comment period from 60 days to 91 days. 

The NRC staff acknowledges commenters’ concerns about the lack of financial assistance to 

certain stakeholders participating in the NRC’s supplemental EIS process. The NWPA provides 

that the Secretary of DOE shall make financial assistance available through grants to the State 

of Nevada, affected units of local governments, and to affected Indian tribes, for the purpose of 

participating in the licensing process. This funding has been used by the State of Nevada, local 

governmental agencies, and Native Americans to fund participation in DOE’s technical and 

environmental review process. The NRC is not granted authority under the NWPA to provide 

funding for such participation. For this reason, the NRC is not able to provide funding to the 

State of Nevada, affected tribes, or affected units of local government. 

The consideration of Tecopa in the environmental justice analysis is explained in 

Section B.2.4.5.6. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

The NRC staff has revised Section 3.4.2, and updated Tables 3-18 and 3-19, to reflect current 

census information, as well as to correct errors in the demographic data presented in the draft 

supplement. The revisions do not change the NRC staff conclusions in the supplement that 

impacts from the proposed repository would not affect minority and low-income populations 

disproportionately. 

(060, 080-16, 121, 142, 146-03, 148) 

B.2.4.5.3. COMMENT: Several commenters oppose the Yucca Mountain project due to 

environmental justice concerns. Commenters expressed concerns that the Yucca Mountain 
B–81 

project would contaminate land and water that the Native American community rely on for 

religious purposes. Two commenters expressed their view that DOE’s process and policies of 

studying cultural and historic resources at Yucca Mountain is equivalent to environmental 

racism because, for example, the traditional Western Shoshone government of Newe Sogobia 

was not invited to participate. The commenters further stated that DOE ethnographic studies 

failed to identify the Newe, as governed by their own traditional form of tribal government. The 

commenters added that the Yucca Mountain project would violate the Treaty of Ruby Valley and 

the Proxmire Act. 

RESPONSE: The NRC staff acknowledges commenters’ concerns about environmental justice 

associated with the proposed repository. Those comments concerning the Genocide 

Convention Implementation Act (the Proxmire Act), the Treaty of Ruby Valley, and DOE’s 

environmental justice policies and process are outside the scope of the supplement, which 

concerns an assessment of the potential impacts to groundwater and from surface discharges 

of groundwater beyond the postclosure compliance location, which is 18 km [11 mi] from the 

Yucca Mountain project site. The scope of this supplement is further described in the NRC’s 

Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). 

The NRC staff reviewed DOE’s evaluation of impact on Native Americans in Section 3.2.1.4.3 of 

its ADR. The NRC staff found that DOE’s evaluation of those impacts was adequate. The 

staff’s assessment concerning impacts to Native Americans and to cultural and historic 

properties can be found in Sections 3.3 and 3.4 of the supplement. 

No changes were made to the supplement in response to these comments. 

(010, 021, 024, 43, 108, 131, 147-10) 

B.2.4.5.4. COMMENT: One commenter suggested that because all communities in the 

area around the groundwater discharge locations rely upon groundwater and surface water, 

there is nothing unique about the Timbisha Shoshone Tribe in this respect. 

RESPONSE: The supplement considers annual groundwater withdrawal estimates and 

pumping rates to be part of the affected environment in Chapter 2 and assesses them in order 

to determine the potential effects of groundwater pumping on groundwater flow and conditions. 

The commenter refers to a statement in Section 2.1.1 of the supplement regarding the Timbisha 

Shoshone Tribe’s Federal groundwater appropriation rights. This information is provided in the 

context of describing characteristics of population centers in Death Valley. The Timbisha 

Shoshone Tribe’s groundwater rights are referenced in other places in the supplement in the 

context of establishing potential dose pathways (Section 3.1.2.2), potential effects on cultural 

resources (Section 2.3.2), and environmental justice communities (Section 3.4.2). The NRC 

staff recognizes that Native Americans use water for spiritual, healing, and other purposes. 

Section 3.4.2 of the supplement assesses the potential human health and environmental effects 

that contaminated groundwater from the repository could have on minority and low-income 

populations. The NRC staff determined there would be no disproportionately high and adverse 

human health or environmental effects, including impacts on historic and cultural resources, on 

any population from the uses or discharges of groundwater flowing from the repository beyond 

the postclosure compliance location. 
B–82 

No changes were made to the supplement as a result of this comment. 

(046)

B.2.4.5.5. COMMENT: The NRC received comments that radiological health and impacts 

from exposure to radiation are an environmental justice concern. The commenters expressed 

their views that no amount of radiation is safe and that any source of radiation represents a 

continuation of impacts already experienced by EJ communities as a result of nuclear weapons 

testing and other activities. 

RESPONSE: The NRC staff acknowledges that minority and low-income populations may have 

been affected disproportionately by past weapons testing. The staff also recognizes that 

radiological impacts should be considered in an environmental justice analysis. Section 3.4.2 of 

the supplement assessed the potential human health and environmental effects that 

contaminated groundwater from the repository could have on minority and low-income 

populations. In the supplement, the NRC staff determined that development of the 

Yucca Mountain repository would not have disproportionate effects on minority and low-income 

populations. In addition, in Chapter 4 of the supplement, the NRC staff considered the potential 

cumulative impacts of the proposed repository, when added to other reasonably foreseeable 

future actions, and likewise found those impacts not to disproportionately impact environmental 

justice communities. 

The supplement concludes that the dose to members of the public would be small, and the 

doses calculated in the supplement are also a fraction of the average background radiation 

exposure received by the public each year. 

The NRC staff has revised Section 3.4.2, and updated Tables 3-18 and 3-19, to reflect current 

census information, as well as to correct errors in the demographic data presented in the draft 

supplement. The revised text does not change the NRC staff conclusions in the supplement 

that impacts from the proposed repository would not affect minority and low-income populations 

disproportionately. 

(024, 063, 146-12, 147-10) 

B.2.4.5.6. COMMENT: A commenter suggested that the NRC’s environmental justice 

analysis does not recognize the community of Tecopa as disadvantaged. The commenter also 

stated that the community relies on ecotourism, which would be impacted negatively by a 

repository. 

RESPONSE: The NRC staff acknowledges that California designates Tecopa as a 

disadvantaged community, and that environmental justice planning programs of local 

governments include Tecopa. The NRC staff’s environmental justice analysis is described in 

Section 3.4.2 of the supplement. The staff evaluated the potential for disproportionately high 

and adverse human health or environmental effects on minority and low-income populations 

from groundwater and surface discharges of groundwater downstream of the postclosure 

compliance location, consistent with NRC guidance for identifying those communities in 

NUREG-1748 (NRC, 2003). The NRC staff evaluated the characteristics of affected 

communities to determine if they might experience unique potential impacts. Tecopa, as well 

as other communities in Death Valley, is encompassed within the 12,217-km2

 [4,717-mi2] 

Death Valley Census County Division (CCD) that the NRC staff evaluated. The Death Valley 
B–83 

CCD extends approximately from the southern boundary of Tecopa to Ubehebe Crater in the 

north, to the California/Nevada State line in the east, and Panamint Springs in the west. 

The NRC staff has revised Section 3.4.2, and updated Tables 3-18 and 3-19, to reflect current 

census information, as well as to correct errors in the demographic data presented in the draft 

supplement. The revised text does not change the NRC staff conclusions in the supplement 

that impacts from the proposed repository would not affect minority and low-income populations 

disproportionately. Comments concerning tourism impacts are addressed in Section B.2.4.6.1. 

(134, 149-10)

B.2.4.5.7. COMMENT: A commenter expressed concern that the supplement does not 

consider people who are more susceptible to radiation exposures because of cultural practices 

or because they consume food and milk produced in the Amargosa Valley. 

RESPONSE: The NRC staff disagrees with the comment. The staff’s dose calculations for 

members of the farming community in Amargosa Valley are based on conservative assumptions 

about the area and about agricultural practices, as further discussed in Section 3.1.1. For 

example, the radiological dose to an individual from well-pumping and irrigation at Amargosa 

Farms is calculated using the highest concentration of a plume within the postclosure 

compliance location. Appendix A of the supplement describes how the Amargosa Farms dose 

was calculated. The maximum dose calculated by the NRC staff is a peak annual dose of 

1.3 mrem [0.013 mSv] per year. The maximum dose is only a small fraction of the background 

radiation dose of 300 mrem/yr [3.0 mSv/yr], which includes radon. Furthermore, the maximum 

dose is much less than the NRC annual dose standards for the Yucca Mountain repository 

published in 10 CFR Part 63. The regulatory limits are 15 mrem [0.15 mSv] for the first 

10,000 years, and 100 mrem [1 mSv] from 10,000 years to one million years after 

permanent closure. 

No changes were made to the supplement as a result of this comment. 

(146-01)

B.2.4.5.8. COMMENT: One commenter suggested that the minority population of 

Nye County, as presented in Table 3-18 of the supplement, is incorrect. The commenter did not 

provide a source for this information. 

RESPONSE: The NRC staff agrees that the draft supplement contained errors in the presented 

demographic data. The NRC staff has revised Section 3.4.2 and updated Tables 3-18 and 3-19 

to reflect current census information and to correct errors in the demographic data presented in 

the draft supplement. The revised text does not change the NRC staff conclusions in the 

supplement that impacts from the proposed repository would not affect minority and low-income 

populations disproportionately. 

(138) 
B–84 

B.2.4.6 Other Topics 

Socioeconomics 

B.2.4.6.1. COMMENT: The NRC received comments about potential impacts on tourism in 

Las Vegas and on tourism and agriculture in Inyo County from transporting and storing spent 

nuclear fuel at Yucca Mountain. Commenters voiced concerns that tourism would be impacted 

for reasons related to security, accidents, contaminated groundwater, and public fear. One 

commenter stated that ecotourism in the Amargosa Valley area has increased since the decline 

of the mining industry. One commenter provided a reference to a 2010 socioeconomic impact 

study that predicted tourism and agriculture-related revenue decreases to Inyo County from the 

proposed Yucca Mountain high-level nuclear waste repository (Gruen Gruen & Associates, “A 

County at Risk: The Socio-economic Impacts of the Proposed Yucca Mountain High-level 

Nuclear Waste Repository,” 2010). Another commenter stated that the area economy is 

vulnerable and can be affected by anything that affects Nevada. 

RESPONSE: The NRC staff acknowledges the concerns about potential impacts on tourism 

and agriculture. These comments are outside the scope of the supplement, which concerns an 

assessment of the potential impacts to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 

Socioeconomic effects are addressed in the 2002 and 2008 environmental impact statements 

prepared by DOE. As documented in its ADR, the NRC staff determined that this portion of 

DOE’s analysis is adequate and does not require supplementation. 

No changes were made to the supplement as a result of this comment. 

(034, 066, 127, 142, 147-03, 147-04, 147-18, 149-09, 149-11) 

B.2.4.6.2. COMMENT: One commenter stated that a lot of work remains to be done at 

Yucca Mountain facility and that completing the facility would provide employment for the many 

Nevada workers who are currently unemployed. 

RESPONSE: The NRC staff acknowledges that should the Yucca Mountain project resume, it 

could result in employment opportunities in the region. This comment is outside the scope of 

the supplement, which concerns an assessment of the potential impacts to groundwater and 

surface discharges of groundwater beyond the postclosure compliance location. The scope of 

this supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

Socioeconomic effects, including potential changes to employment from a repository at 

Yucca Mountain, are addressed in the 2002 and 2008 environmental impact statements 

prepared by DOE. As documented in its ADR, the NRC staff determined that this portion of 

DOE’s analysis is adequate and does not require supplementation. 

No changes were made to the supplement as a result of this comment. 

(147-25) 
B–85 

General Safety Concerns 

B.2.4.6.3. COMMENT: Several commenters expressed concerns related to the integrity of 

the waste containers or their design. Some commenters cited the salinity of the 

Yucca Mountain environment and the oxidizing conditions of the repository as leading to 

enhanced corrosion. One commenter expressed concern that the proposed storage containers 

are not thick enough to withstand corrosion. Finally, a commenter suggested that casks on the 

surface could not survive an accidental or intentional aircraft crash without damage. 

RESPONSE: The NRC staff acknowledges the concerns expressed by the commenters about 

waste container safety, both at the proposed geologic repository operations area and in 

Yucca Mountain. These comments are outside the scope of the supplement, which concerns 

an assessment of the potential impacts to groundwater and on surface discharges of 

groundwater beyond the postclosure compliance location, which is 18 km [11 mi] from the 

Yucca Mountain project site. The scope of this supplement is further described in the NRC’s 

Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). 

The NRC staff’s evaluation of information on degradation of waste containers postclosure is 

contained in Volume 3 of the staff’s SER for the Yucca Mountain repository license application 

(NRC, 2014a, Chapters 4 and 6). Information about the risks associated with aircraft crashes at 

the geologic repository operations area is contained in Volume 2 of the SER (NRC, 2015a, 

Chapter 3) and Section 3.2.1.4.4 of the NRC staff’s ADR (NRC, 2008a). These documents are 

available on the NRC’s Web site at http://www.nrc.gov/waste/hlw-disposal/key-documents.html. 

No changes were made to the supplement as a result of these comments. 

(080-01, 088, 095-08, 128, 147-15, 148)

B.2.4.6.4. COMMENT: Commenters expressed general doubt or skepticism that the 

repository will be safe. While expressing their disapproval, some commenters also mentioned 

specific concerns about the suitability of the site and about transportation, terrorism, accidents, 

impacts to Native Americans, impacts to wildlife, the potential for leakage, and the long 

timeframes under consideration. 

RESPONSE: The NRC staff acknowledges the concerns expressed by the commenters. 

Comments concerning site suitability, transportation, terrorism, accidents, and the potential for 

leakage from the repository are outside the scope of the supplement, which concerns the 

potential impacts to groundwater and from surface discharges of groundwater beyond the 

postclosure compliance location. The scope of this supplement is further described in the 

NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). Sections B.2.4.2, B.2.4.4, and B.2.4.5 of this appendix address comments about 

groundwater impacts on Native Americans, and Section B.2.4.3 addresses comments 

concerning wildlife. Section B.2.2.1 addresses comments about the long timeframe under 

consideration in this supplement. 

The NRC staff’s SER and ADR are available on the NRC’s Web site at 

http://www.nrc.gov/waste/hlw-disposal/key-documents.html. In addition, the NRC’s Web site 

at http://www.nrc.gov/waste.html provides information about various aspects of nuclear 

waste disposal. 
B–86 

No changes were made to the supplement as a result of these comments.

(008, 017, 034, 041, 044, 077, 086, 095-07, 107, 111, 146-01, 146-13, 147-06, 147-20, 148, 

149-13) 

B.2.4.6.5. COMMENT: Several commenters expressed general concerns about the safety 

of the proposed Yucca Mountain repository and also expressed concerns and doubts about 

geologic, seismic, hydrologic, and container corrosion processes that could compromise 

repository safety. Other commenters expressed concerns about radionuclide releases, 

terrorism, and titanium drip shields. Other commenters stated that scientific studies of 

Yucca Mountain are flawed because of bias in favor of positive results or inadequate quality 

assurance. Some commenters stressed the considerable uncertainty associated with predicting 

the long-term behavior of the repository, referring in some cases to the Waste Isolation Pilot 

Plant, the accident Fukushima Dai’ichi, or Love Canal. One commenter labelled the conclusion 

that the potential impacts would be small “premature” because of these uncertainties. 

RESPONSE: The NRC staff acknowledges the concerns expressed by these commenters. 

Sections B.2.2.2, B.2.2.3, and B.2.4 of this appendix address comments on radionuclide 

releases from the repository. Section B.2.2.1 addresses comments on the long timeframe 

under consideration in this supplement. Comments regarding terrorism, drip shields, and 

processes in the environment that could affect repository integrity are outside the scope of the 

supplement, which concerns the potential impacts to groundwater and from surface discharges 

of groundwater beyond the postclosure compliance location. The scope of this supplement is 

further described in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in 

the NRC staff’s ADR (NRC, 2008a). 

The NRC staff’s evaluation of DOE’s license application is contained in the staff’s SER for the 

repository license application (NRC, 2010, 2014a,b, 2015a,b) and in its ADR (NRC, 2008a) for 

DOE’s repository EISs. These documents are available on the NRC’s Web site at 

http://www.nrc.gov/waste/hlw-disposal/key-documents.html. In addition, the NRC’s Web site at 

http://www.nrc.gov/waste.html provides information about various aspects of nuclear waste 

disposal. 

No changes were made to the supplement as a result of these comments. 

(012, 015, 019, 045, 066, 067, 080-06, 086, 088, 090, 100, 108, 146-04, 147-03, 147-06, 

149-14) 

 Transportation 

B.2.4.6.6. COMMENT: Commenters stated that the supplement should have addressed a 

number of issues related to the transportation of spent nuclear fuel to the proposed repository. 

Many commenters stated that the designation of the Great Basin Monument by President 

Obama in July 2015 would affect transportation routing of spent fuel to the proposed repository. 

The commenters requested that the analyses in the supplement be updated to consider 

possible changes in transportation routes. Several commenters raised concerns with the safety 

of spent fuel transportation, specifically whether emergency response capabilities and aging 

transportation infrastructure would be able to support spent fuel shipments. Other safety-related 

comments on transportation requested that new or updated analyses consider the impacts of 

spent fuel transportation accidents on Native American interests, the cumulative risks to the 
B–87 

region of the transportation of radioactive materials, and the risks of transporting damaged fuel 

and high-burnup spent fuel to the repository. One commenter suggested the analyses be 

updated to reflect changes in spent fuel storage and transportation requirements. Several 

commenters expressed concern about the potential risk of accidents involving rail shipments of 

spent fuel and crude oil, and the possibility of a subsequent fire. Another commenter was 

concerned with the risk of accidents involving barge shipments of spent fuel and the challenges 

of responding to this type of accident. 

Commenters suggested that the supplement should have analyzed the potential for national and 

local impacts from spent fuel transportation accidents and sabotage events on surface water 

and groundwater. One commenter objects to the use of probabilistic risk assessment methods 

in analyzing groundwater contamination scenarios, because these transportation risk 

assessments state extremely low probability rates, despite cancer risks. Another commenter 

noted that the entire area impacted by repository groundwater releases in Amargosa Valley and 

much of northern Death Valley overlaps the 50-mile region of influence for rail shipments 

along the Caliente and Mina rail alignments, as well as the route for truck shipments along 

US Highway 95. The commenter asserted that the evaluation of cumulative impacts in the draft 

supplement failed to consider the potential impacts of radiological releases from transportation 

accidents and sabotage events on surface and groundwater resources within the region of 

influence. 

Commenters expressed concerns that the scope of the supplement is too narrow. One 

commenter suggested the importance of the supplement is being overlooked as it may lead to 

completing the DOE license application and issuing a construction authorization for the DOE 

facility. Two commenters noted that interstate transportation of nuclear waste warrants 

expanding the scope of this supplement to a national scope. 

RESPONSE: The NRC staff acknowledges the concerns expressed by many commenters 

about the transportation of spent nuclear fuel to the proposed repository. These comments are 

outside the scope of the supplement, which concerns an assessment of the potential impacts of 

repository releases to groundwater and surface discharges of groundwater beyond the 

postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain project site. 

The scope of this supplement is further described in the NRC’s Notice of Intent to prepare the 

supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

Transportation impacts are addressed in DOE’s 2002 and 2008 EISs (DOE, 2002; 2008). In the 

ADR, the staff determined that DOE considered spent fuel transportation impacts in its 2002 

and 2008 EISs, in accordance with NRC regulations and applicable guidance. Moreover, the 

NRC staff did not identify portions of DOE’s spent fuel transportation impact analyses that 

required supplementation. The NRC staff’s ADR concluded that supplementation is necessary 

only to evaluate impacts to groundwater and from potential surface discharges of groundwater 

beyond the postclosure compliance location. The supplement examines the potential for 

subsurface groundwater transport of repository releases to downstream locations, which is an 

entirely different process than the transportation of spent fuel by truck, railcar, or barge to the 

proposed repository. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 
B–88 

No changes were made to the supplement in response to these comments. 

(006, 018, 019, 034, 048, 060, 069, 074, 080-05, 080-16, 084, 095-02, 095-11, 95-12, 118, 122, 

123, 128, 138, 141, 146-02, 146-06, 146-13, 146-14, 147-15, 147-24, 147-25, 148) 

Seismic and Volcanic Events 

B.2.4.6.7. COMMENT: Commenters expressed concern regarding seismic (earthquake) 

and/or tectonic risks in the Yucca Mountain area. Some commenters indicated that seismic 

studies have shown that Yucca Mountain is not a viable area in which to build a repository and 

provided information about local faults and earthquakes. Another commenter noted that a local 

Native American name for Yucca Mountain attests to its instability. 

One commenter stated that the results of peak ground motion studies applied to the 

Yucca Mountain area that were conducted after DOE submitted its license application to the 

NRC are lower than originally determined. The commenter stated that the possible impact of 

this on the EIS supplement results, when combined with recent determinations of smaller 

groundwater infiltration rates, would be a lowering of the estimated radionuclide doses from the 

repository. The commenter suggested that these results should be mentioned in the final 

supplement. 

RESPONSE: The NRC staff acknowledges the concerns expressed by the commenters about 

seismic and tectonic events in the area of Yucca Mountain. These comments are outside the 

scope of the supplement, which concerns an assessment of the potential impacts to 

groundwater and surface discharges of groundwater beyond the postclosure compliance 

location, which is 18 km [11 mi] from the Yucca Mountain project site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The NRC staff’s evaluation of information relating to the geology and geologic hazards of the 

region around the repository is contained in Volume 2 of the staff’s SER for the Yucca Mountain 

repository license application (NRC, 2015a, Chapters 1 and 3) and in the staff’s ADR 

(NRC, 2008a) for DOE’s EISs. These documents are available on the NRC’s Web site at 

http://www.nrc.gov/waste/hlw-disposal/key-documents.html. 

Preparation of this supplement is one of several steps in the licensing process for the proposed 

repository. Information may be identified that requires further supplementation of DOE’s 2002 

and 2008 EISs in the future. The completion of licensing activities is subject to appropriations 

and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(013, 080-13, 086, 088, 095-04, 127, 138) 

B.2.4.6.8. COMMENT: Commenters expressed concern regarding seismic (earthquake) 

and volcanic (igneous) risks of the Yucca Mountain area. A commenter stated that due to the 

volcanic and earthquake activity in the general vicinity of Yucca Mountain, disruptive events will 

take place but are estimated not to have severe effects. Other commenters expressed concern 

about the potential for damage to repository integrity or the contamination of groundwater as a 

result of earthquake or volcanic activity. One commenter suggested that earthquake or volcanic 

activity could produce an early waste package breach, and the commenter thus disagrees with 
B–89 

the conclusion in the supplement that impacts to groundwater resources would be small. This 

commenter also expressed concern about the one million year timeframe for the analysis and 

questioned how the supplement could make conclusions about impacts over this length of time. 

RESPONSE: The NRC staff acknowledges the concerns expressed by the commenters about 

seismic and volcanic events in the area of Yucca Mountain over a one-million-year period. 

These comments are outside the scope of the supplement, which concerns an assessment of 

the potential impacts to groundwater and surface discharges of groundwater beyond the 

postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain project site. 

The scope of this supplement is further described in the NRC’s Notice of Intent to prepare the 

supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The NRC staff’s evaluation of information relating to the geology, including seismicity and 

volcanism, of the region around the repository is contained in Volume 3 of the staff’s SER for 

the Yucca Mountain repository license application (NRC, 2014a, Chapters 6 and 9 through 12) 

and in the staff’s ADR for DOE’s EISs (NRC, 2008a). These documents are available on the 

NRC’s Web site at http://www.nrc.gov/waste/hlw-disposal/key-documents.html. Comments 

regarding the million-year timeframe are addressed in Section B.2.2.1. 

No changes were made to the supplement as a result of these comments. 

(019, 041, 066, 100, 128) 

B.2.5 Cumulative Impacts 

B.2.5.1. COMMENT: Many commenters described what they believed to be past, 

present, or reasonably foreseeable future actions related to the NNSS (formerly the Nevada 

Test Site) operations that have a high potential to contribute to cumulative impacts. These 

actions include nuclear weapons tests, transportation and disposal of low-level radioactive 

waste at the NNSS, and remediation actions for the site. 

Commenters stated that atmospheric nuclear weapons tests were conducted in the vicinity of 

Yucca Mountain from 1951 to 1963, and that underground full-scale tests were conducted at the 

Nevada Test Site from 1963 to 1992. They asserted that many of these tests leaked 

radioactivity to the atmosphere and environment and contaminated regional groundwater. They 

stated that after 1992, nuclear weapons testing continued at the Nevada Test Site as subcritical 

experiments involving plutonium. One commenter suggested the supplement would not be 

complete unless it includes the environmental impacts of bomb test contamination and cited 

information in a report [“Focused Evaluation of Selected Remedial Alternatives for the 

Underground Test Area - DOE/NV465 (UC-700)”], published by the DOE Nevada Operations 

Office in Las Vegas, Nevada (DOE, 1997). Specifically, the commenter referred to Table 8-1 

of the report, stating that ultimately the least expensive remedial alternative was selected 

(long-term monitoring under the “Institutional Control” alternative) until a permanent remediation 

solution is identified. The commenter argued that, therefore, contamination of the subsurface by 

at least one metric ton of plutonium-239 that is not being remediated and should cause the NRC 

staff to change the cumulative environmental impact conclusions in the supplement to LARGE. 

Several commenters also expressed concerns that transportation and disposal of low-level 

radioactive waste (LLRW) at the NNSS would contribute to cumulative impacts. One 

commenter noted that waste from the Manhattan Project and other nuclear activities around the 

country has been transported to the NNSS for storage for several decades. The commenter 
B–90 

suggested spills and leaks have occurred at the NNSS. The commenter further noted the 

recent fire at the closed LLRW facility near Beatty, Nevada, has contributed to the legacy of 

nuclear activities in the vicinity of Yucca Mountain. 

One commenter commended the NRC staff for the complete and thorough evaluation of 

activities that have occurred since DOE submitted its last EIS, as supplemented, in 2008.

RESPONSE: Cumulative impacts are evaluated in Chapter 4 of the NRC staff’s supplement. 

Section 4.3 of the supplement describes the other past, present, and reasonably foreseeable 

future actions considered in the NRC staff’s analysis of cumulative impacts. Section 4.4.1 of the 

supplement describes actions identified in DOE’s 2002 and 2008 EISs (DOE, 2002; 2008a) and 

notes that DOE had considered information about contaminants in groundwater from past 

activities at the NNSS in its cumulative impact analysis. These past activities at the NNSS 

encompass the issues of concern raised by commenters, such as the impacts to groundwater 

from past nuclear weapons tests, disposal of LLRW, and remediation actions. 

The impacts from the transportation of wastes to the NNSS are addressed in DOE’s EIS for the 

site (DOE, 2013a). But these specific impacts, beyond their cumulative impacts, are outside the 

scope of the supplement (see responses to comments about Transportation and the scope of 

the supplement in Section B.2.4.6.6 of this Appendix) 

In developing the supplement, the NRC staff identified and incorporated information about the 

NNSS (DOE, 2013a) that was unavailable when DOE developed its 2002 and 2008 EISs 

(supplement Sections 4.4.2 and 4.5). This information includes the most recent evaluations of 

potential impacts to groundwater from past, present, and reasonably foreseeable future actions 

at the NNSS, including nuclear weapons tests, disposal of LLRW, and remediation actions. 

The NRC staff reviewed the DOE report on remedial action alternatives for the Underground 

Test Area at the Nevada Test Site (DOE, 1997) and found that remedial actions for the 

Underground Test Area were evaluated in DOE’s NNSS EIS (DOE, 2013a), which was 

considered in the draft supplement. 

The NRC staff does not agree that remedial actions requiring continued long-term monitoring of 

groundwater with institutional controls at the NNSS significantly increase the potential 

cumulative impacts of the proposed repository. Similar long-term caretaking approaches are in 

operation at other radioactively contaminated sites, including uranium mill tailings sites. 

Continued monitoring requires the long-term caretaker to track the movement of contaminants 

in groundwater over long periods and identify and mitigate potential future risks. 

The conservative analyses in the supplement in Sections 4.5.1 and 4.5.2.2 provide the basis for 

the NRC staff’s conclusion that the transport of tritium from NNSS could contribute to cumulative 

radiological impacts on groundwater along the flow path from the repository. However, these 

impacts would be negligible at the locations evaluated in the supplement because radioactive 

contaminants (including those potentially from other NNSS activities) will attenuate and decay 

as they move through the groundwater flow path from the repository. DOE considered 

cumulative impacts from NNSS in its 2002 EIS, and the supplement discusses this issue in 

Section 4.5.1. While the commenter mentions that large amount of radioisotopes, including 

Pu239, are present below the surface of the NNSS from nuclear weapons testing, the NRC staff 

concludes that only a small fraction of this inventory is likely to move beyond the contaminated 

locations at the site (see also DOE, 2013a, Appendix H). The NRC staff also notes in 
B–91 

Section 4.4.2 of the supplement that DOE stated that it will continue its management of NNSS 

waste. The NRC staff discussion of concerns about the recent fire at the closed Beatty LLRW 

disposal site is in Section B.2.5.2. 

The NRC staff revised Section 4.4.2 of the supplement in response to the comment. The staff’s 

description of the scope of the NNSS EIS (DOE, 2013a) now includes DOE environmental 

management activities. 

(002, 003, 004, 008, 013, 014, 022, 027, 028, 031, 039, 040, 047, 048, 053, 054, 055, 064, 069, 

071, 075, 078, 079, 082, 083, 085, 092, 093, 094, 101, 104, 112, 138, 139, 139, 146-07) 

B.2.5.2. COMMENT: Commenters suggested the final supplement needs to account for 

the potential contribution to cumulative impacts of a fire that occurred in October 2015, at the 

LLRW disposal facility in Beatty, Nevada. One of the commenters further added that the draft 

supplement fails to provide a sufficient analysis of cumulative impacts associated with the 

movement of contaminants through groundwater into the Amargosa desert and Inyo County 

from the proposed repository in combination with contaminants from the NNSS and the Beatty 

low-level waste disposal site and hazardous waste facility.

RESPONSE: The NRC staff acknowledges commenters’ concerns about the fire at the LLRW 

disposal facility in Beatty, Nevada, on October 18, 2015. The potential impacts from the Beatty 

site, beyond their cumulative impacts, are outside the scope of the supplement, which concerns 

an assessment of the potential impacts to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain 

project site. Additional information about the Beatty event is provided below. The scope of 

this supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

On December 30, 2015, the Nevada Department of Public Safety (NDPS), State Fire Marshal 

Division published an incident report (NDPS, 2015), which determined the fire was caused by 

settling of the waste that produced openings in the waste trench cover. The report notes that 

openings in the cover allowed water from a storm event to infiltrate into a disposal trench 

containing drums of metallic sodium. The report points out that the combination of water and 

metallic sodium caused an exothermic (heat-generating) chemical reaction producing hydrogen 

gas and heat. The heat generated by the sodium-water reaction ignited combustible metals in 

the immediate area, resulting in a fire that burned for several hours. The incident report 

concluded that no injuries to personnel occurred, that the effects of the fire were contained to 

the immediate site, and no radioactive materials were released due to the fire. 

The joint agency investigation team led by the NDPS, State Fire Marshal Division, and including 

representatives from the Nevada Department of Health and Human Services, Radiation Control 

Program and the Nevada Department of Conservation and Natural Resources, Division of 

Environmental Protection, recommended the development of an interim action plan to promptly 

address cleanup of displaced materials and safeguard the facility against additional storm 

events. The team also recommended that a long-term action plan with a detailed evaluation of 

the existing LLRW facility and a proposal of measures to ensure long-term sustainability of the 

disposal facility be prepared. Interim repairs were completed prior to publication of the incident 

report; these include collecting displaced materials, replacing drums into the trench for burial, 

adding fill, and repairing the damaged portions of the cap to prevent the entry of moisture. The 

incident report indicates that local, State and Federal agencies are working on long-term 

solutions for stabilization of the site. 
B–92 

Section 4.5.1 of the supplement explains that DOE’s cumulative impacts analysis was based on 

the small quantity of radionuclides at the Beatty facility in relation to the quantity that could be 

released by the repository. The NRC staff reviewed the NDPS’s incident report and the 

investigation team’s recommendations and finds that the NRC staff’s evaluation in the 

supplement of the potential for cumulative impacts from the Beatty facility is not affected by the 

fire. This is because the analysis in the supplement is based on the small quantity of 

radionuclides that could be available for release over a long time frame and the attenuating 

effects of dispersion and radioactive decay along the long flow paths to the downgradient 

locations. In contrast, the fire has raised concerns about the stability of the site over a much 

shorter time frame than is considered in the supplement. 

The supplement was modified in Section 4.5.1 to acknowledge the recent Beatty fire in 

response to these comments. 

(142, 148) 

B.2.5.3. COMMENT: Two commenters expressed concerns that the cumulative impacts 

to Western Shoshone people from activities within the Yucca Mountain region, such as 

operation of the NNSS and regional LLRW disposal, were not considered in the supplement. 

They asserted that differences in aspects of their lifestyle, such as diet, mobility, and shelter, 

produce different risks for the Western Shoshone people. The commenters recommended 

investigation of these impacts as an early warning to protect human health.

RESPONSE: These comments are similar to ones raised concerning the direct and indirect 

impact analyses in the draft supplement. Section B.2.4.2 of this appendix (Public and 

Occupational Health) addresses these issues. The NRC staff’s cumulative impact analysis uses 

the same reasonable and conservative approach as the analysis of direct and indirect public 

health impacts in Sections 3.1.1 and 3.1.2 of the supplement to evaluate potential impacts to 

potentially affected communities. 

No changes were made to the supplement in response to these comments. 

(036, 057) 

B.2.5.4. COMMENT: One commenter suggested that DOE’s and the NRC’s cumulative 

impact analyses lack credible scientific data and, therefore, do not comply with the Council on 

Environmental Quality’s regulation at 40 CFR 1508.27(b).

RESPONSE: Section 4.1 discusses the standards with which the NRC staff’s cumulative 

impacts analysis was developed. CEQ’s regulation at 40 CFR 1508.27 defines “significantly” as 

involving considerations of both context and intensity. Section 1508.27(b) states that intensity 

refers to the severity of impact and includes (i) impacts that may be both beneficial and adverse, 

(ii) the degree to which the proposed action affects public health or safety, (iii) unique 

characteristics of the geographic area, and (iv) the degree to which the effects on the quality of 

the human environment are likely to be highly controversial. The NRC’s NEPA guidance in 

NUREG-1748 (NRC, 2003) in Section 4.2.5.3 adopts these concepts for cumulative impact 

analysis. These concepts are incorporated in the supplement, as discussed in Section 4.1. The 

NRC staff’s cumulative impact determinations are supported by relevant technical data and 

studies, including DOE’s 2002 and 2008 EISs (DOE, 2002; 2008a); the DOE license application 
B–93 

(DOE, 2008b); the NNSS EIS (DOE, 2013a); the DOE postclosure groundwater impact analysis 

(DOE, 2014); and NRC’s analyses of this information, including its SER, which was completed 

in January 2015 (NRC 2010, 2014a,b, 2015a,b). 

No changes to the EIS supplement are needed to address the comment. 

(116) 

B.2.5.5. COMMENT: Two commenters expressed concerns that the supplement should 

evaluate the cumulative impacts of transportation-related radiological exposure risks. One 

commenter asserted that the final supplement must identify DOE’s proposed transportation of 

high-level radioactive waste as a foreseeable future action in its consideration of cumulative 

impacts and also account for the potential loss of the Caliente rail alignment as a route. Another 

commenter noted DOE’s analyses of radiological impacts of transportation accidents or 

sabotage events in the 2008 final supplemental EIS for the repository and the EIS for the rail 

alignment “acknowledged that ‘the region of influence was 80 km [50 mi] from the railroad or 

highway.’” The same commenter stated that the entire area impacted by repository groundwater 

releases in Amargosa Valley and much of northern Death Valley is located within this region of 

influence for rail shipments and for truck shipments. The commenter identified numerous 

surface water resources within this region of influence, noting the evaluation of cumulative 

impacts in the draft supplement failed to consider the potential impacts on these surface and 

groundwater resources from transportation accidents and sabotage events.

RESPONSE: The NRC staff acknowledges the concerns expressed about spent fuel 

transportation accidents. Similar comments about transportation impacts are addressed in 

greater detail in Section B.2.4.6.6 of this appendix. However, these comments are outside the 

scope of the supplement, which concerns an assessment of the potential impacts to 

groundwater and surface discharges of groundwater beyond the postclosure compliance 

location, which is 18 km [11 mi] from the Yucca Mountain project site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(123, 148) 

B.2.5.6. COMMENT: One commenter stated that the evaluation of mining impacts in the 

draft supplement’s cumulative impact analysis is not adequately supported by an analysis of 

future market conditions. The commenter suggests that the NRC staff ignored the potential 

impacts of future mining activities, described by the BLM, in its Draft Resource Management 

Plan, as potentially “negligible to moderate,” by asserting that impacts would be addressed 

“through best management practices and other mitigation.” The commenter stated that the 

supplement does not contain any meaningful analyses of future market conditions or industry 

practices to support its conclusion that impacts would remain low as a result of mitigation.
B–94 

RESPONSE: Section 4.4.2 of the supplement provides additional information about the 

potential impacts of mining in the analysis of cumulative impacts. The NRC staff’s analysis 

considered the analyses and conclusions of the BLM Las Vegas and Pahrump Field Offices 

Draft Resource Management Plan/Environmental Impact Statement (BLM, 2014). In that report, 

the BLM describes historic, current, and future trends in mining activities in regions of southern 

Nevada and evaluates the potential environmental impacts. The range of impacts described by 

the NRC staff in the draft supplement (as negligible to moderate considering mitigation 

measures) are derived from its review of the information and conclusions in the BLM’s Draft 

EIS. The NRC staff disagrees that BLM’s impact conclusions highlighted by the commenter are 

not adequately analyzed and described in the SEIS. 

No changes were made to the supplement in response to this comment. 

(148) 

B.2.5.7. COMMENT: One commenter mentioned a Southern Nevada Water Authority 

plan to construct a large-capacity pipeline in Nevada's Great Basin that would extract 

groundwater in northern Nevada for use in southern Nevada. The commenter cited a 2009 BLM 

EIS (as BLM Document no: 8111 BLM NV040-09-1740B 2009, page 6-3) of the pipeline right-ofway and noted the potential for large impacts on flora and fauna from the proposed removal of 

groundwater. The commenter further noted that Nevada’s Great Basin is located within Newe 

tribal lands and stated that the Southern Nevada Water Authority plan for the Great Basin would 

have consequences in northern Nevada that would be similar to the consequences in southern 

Nevada of activities at the NNSS. They added the impacts would affect the existence of the 

Newe Spiritual World and the Newe itself.

RESPONSE: The NRC staff acknowledges the commenter’s concerns about impacts from a 

major water project. However, these comments are outside the scope of this supplement, which 

concerns an assessment of the potential impacts to groundwater and surface discharges of 

groundwater beyond the postclosure compliance location, which is 18 km [11 mi] from the 

Yucca Mountain project site. The scope of this supplement is further described in the NRC’s 

Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). 

The NRC staff was unable to locate the 2009 BLM document referenced by the commenter; 

however, the NRC staff believes the commenter is referring to the Southern Nevada Water 

Authority Groundwater Development Project for Clark, Lincoln, and White Pine Counties 

(SNWA, 2016). For this project, the Southern Nevada Water Authority proposed a buried 

pipeline system to convey groundwater from central and eastern Nevada to Southern Nevada to 

enhance the area’s limited water resources. The stated purpose of the project is to reduce 

southern Nevada’s reliance on water from the Colorado River, provide flexibility to respond to 

drought conditions in the river system, allow the Southern Nevada Water Authority to meet 

future projected water demand in Clark County, and to provide capacity for Lincoln County to 

convey water rights within Lincoln County. 

BLM completed the final EIS for the right-of-way for this project in 2012 (BLM, 2012c). The BLM 

EIS evaluated the hydrographic basins within portions of Clark, Lincoln, and White Pine 

counties north of Las Vegas and a small portion of Nye County in the area north of Lincoln 

County. This region encompasses the Great Basin National Park and portions of surrounding 

areas. These areas are distant from the affected environment evaluated in the supplement, and 
B–95 

the BLM EIS indicates that these proposed withdrawals would not cause significant impacts to 

the groundwater system at Ash Meadows, Amargosa Valley, or beneath Yucca Mountain. This 

inter-basin transfer water project is also discussed in Section B.2.1.4.11. 

No changes were made to the supplement in response to this comment. 

(070) 

B.2.5.8. COMMENT: One commenter expressed concerns about how the potential for 

expansion of repository capacity was addressed in the cumulative impact assessment. The 

commenter noted that the draft supplement excludes consideration of emplacement of wastes in 

a Yucca Mountain repository beyond the 70,000 MTHM limit because the NWPA prohibits such 

emplacement until a second repository is in operation, and that the NRC staff regards a second 

repository as not reasonably foreseeable. The commenter noted that DOE included “detailed 

plans” for the expansion of repository capacity in its 2008 supplemental EIS and that this 

information contradicts the NRC staff’s assertion that the expansion of repository capacity is 

speculative and not reasonably foreseeable.

RESPONSE: Section 4.4.1 of the supplement explains that DOE’s proposed action, as 

described in its 2002 and 2008 EISs (DOE, 2002; 2008a) and in its Safety Analysis Report 

(SAR) (DOE, 2008b), is the construction of a repository and emplacement of up to 

70,000 metric tons of spent nuclear fuel and high-level radioactive waste. In these EIS analyses 

of cumulative impacts, DOE also described two future actions for the emplacement of waste 

beyond the 70,000-metric-ton limit. DOE referred to these scenarios as inventory modules and 

evaluated them as reasonably foreseeable. These inventory modules proposed for the 

Yucca Mountain repository would contain additional spent fuel, other high-level waste, and 

greater-than-class-C waste. The NRC staff does not consider the proposed inventory modules 

to be reasonably foreseeable future actions because (i) DOE did not evaluate the additional 

waste inventories in its license application; and (ii) both modules are prohibited by the NWPA 

until a second repository is built and in operation. The NRC staff concludes that a second 

repository is not reasonably foreseeable at this time because NRC has not yet licensed one 

repository, and a second repository is not under consideration. 

No changes were made to the supplement in response to this comment. 

(148) 

B.2.5.9. COMMENT: A commenter asked if there is a way to differentiate between the 

radioactive materials that could be released from the NNSS and the radioactive materials that 

could be released from Yucca Mountain.

RESPONSE: Radionuclides present at the NNSS are also found in the commercial spent fuel 

that DOE proposes to emplace at Yucca Mountain. It may be possible to determine the origin of 

contaminants based on the relative abundance of different isotopes or other materials unique to 

each source of contaminants in a water sample; however, contaminant release and transport 

processes can obscure these distinctions. The current DOE environmental management 

program obligations described in the NNSS EIS (DOE, 2013a) include groundwater monitoring 

downgradient of sources of NNSS environmental radiological contamination that are upgradient 

of the Yucca Mountain flow path. 
B–96 

Sections 4.5.1 and 4.5.2.2 of the supplement explain that contamination from the NNSS has the 

potential to interact with Yucca Mountain flow paths. Based on the currently available 

information in the NNSS (DOE, 2013a), the NRC staff evaluated the potential for tritium from the 

NNSS to contribute to the cumulative impacts of the proposed repository. The NRC staff 

concludes that tritium from the NNSS would likely decay to negligible levels before arriving at 

Amargosa Farms and, therefore, would not contribute cumulatively to the impacts from 

contaminants from the repository. 

No changes were made to the supplement in response to these comments. 

(149-16) 

B.2.6 Other Topics 

B.2.6.1 Miscellaneous 

B.2.6.1.1. COMMENT: One comment suggested that the units for uranium concentration 

used in Table 3-2 in the draft supplement be made consistent with the units for uranium in the 

supplement text (i.e., ug/l). 

RESPONSE: The NRC staff corrected relevant text in Section 3.1.1 in response to this 

comment. 

(137)

B.2.6.1.2. COMMENT: Five commenters discussed various aspects of the Yucca Mountain 

project. One statement indicated that the author has no comments on the supplement. Other 

commenters recommended the NRC staff review certain information, including recent NRC 

consideration of greater-than-class-C waste. Two comments point to a movie (“Into Eternity”) 

and a book (“About a Mountain”) of which the commenter stated that NRC should be aware. 

Another commenter stated that there are many problems associated with the Yucca Mountain 

repository project and recommended that the “Engineering Tribute to the Presidential 

Inauguration of January 2017” offers an opportunity to discuss Yucca Mountain issues. 

RESPONSE: The NRC staff acknowledges the information provided by the commenters. 

These comments and references are outside the scope of the supplement, which concerns an 

assessment of the potential impacts to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain 

project site. The scope of this supplement is further described in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

No changes were made to the supplement in response to these comments. 

(80-01, 95-03, 126, 140, 146-11) 

B.2.6.1.3. COMMENT: Three comments addressed matters of location and population for 

the Amargosa Farms and Amargosa Valley area. One requested clarification of distances from 

the regulatory compliance point to the Amargosa Farms pumping area assumed in the 

supplement, and elsewhere. Other comments mention that the Amargosa area is shown as not 

populated on one of the maps in the draft supplement, and that this should be changed. 
B–97 

RESPONSE: The NRC staff has revised Figures 2-1, 2-3, and 2-6 to show Amargosa Farms as 

a populated area. The staff also has revised the text in Section 3.1.1 to clarify that Amargosa 

Farms is not a single location, and that the distance between the postclosure compliance 

location and the groundwater pumping areas in Amargosa Valley of 17 km [11 mi] is based on a 

range of 14 to 20 km [9 to 12 mi] along the groundwater flow path. 

There are residents and businesses between the primary farming areas and the postclosure 

compliance location. Most of the wells supplying water to these residents and businesses are 

close to the farming area. An isolated set of several wells is located just south of the junction of 

Highways 95 and 373, which is consistent with the DOE determination that that there were no 

permanent residents closer than 22 km [13.7 mi] from Yucca Mountain, as described in Section 

2.1.1 of the supplement. Concerning the estimate of impacts for residential and business wells 

closer than 17 km [11 mi] to the compliance location, the NRC staff conservatively adopts the 

analysis in DOE’s 2008 EIS for the RMEI. 

Text in Section 3.1.1 was revised to clarify this distinction. 

(149-01, 149-04, 149-13) 

B.2.6.1.4. COMMENT: Several commenters expressed opposition to the Yucca Mountain 

repository on the basis that ownership of the land is claimed by Native American tribes. One 

commenter noted that the strict standards (e.g., for land ownership) set by the NWPA are not 

being met. One commenter stated that the exterior boundaries of the Newe Sogobia land are 

defined by the 1863 Treaty of Ruby Valley, including Yucca Mountain, and the tribe does not 

consent to the inclusion of its lands into the jurisdiction or boundaries of the United States or 

any other State or territory. The commenter also stated that the tribal ownership of the land is a 

significant encumbrance, precluding licensing of the repository, and the tribe has informed the 

U.S. Government that the land is not for sale. Another commenter stated that Yucca Mountain 

is located on Shoshone land, and that the mountain is “swimming” west. 

RESPONSE: The NRC staff acknowledges the commenters’ concerns about land ownership 

issues involving Native American tribes. These comments are beyond the scope of the 

supplement, which concerns an assessment of the potential impacts of repository releases to 

groundwater and from surface discharges of groundwater beyond the postclosure compliance 

location. The scope of the supplement is further described in the NRC staff’s ADR 

(NRC, 2008a) in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029). 

The NRC does not exercise statutory or regulatory authority over disputes concerning land 

ownership. NRC’s regulations in 10 CFR 63.121 provide that lands within the geologic 

repository operations area must be under DOE’s jurisdiction and control or be permanently 

withdrawn and reserved for DOE’s use. The NRC staff concluded that DOE has not met the 

requirements in 10 CFR 63.121(a) and 10 CFR 63.121(d)(1) regarding the ownership of land 

and certain water rights, as discussed in Volume 4 of its SER (NRC, 2014). 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

 
B–98 

No changes were made to the supplement as a result of these comments. 

(012, 024, 080-01, 086, 131 147-01, 147-10) 

B.2.6.1.5. COMMENT: One commenter stated that NRC has failed to fulfill the Federal 

Government’s trustee obligations to protect tribal lands and interests. The commenter states 

that because the proposed repository may impact lands set aside for the Timbisha (by the 

Timbisha Homeland Act, 16 U.S.C. § 104aa, Pub. L. 106-423, §§ 1-8, Nov. 1, 2000, 114 Stat. 

1875) and because the land status of the reservation can only be changed by the Federal 

Government, the tribe has nowhere else to go if the land or groundwater become contaminated 

or rendered uninhabitable. The commenter stated that, therefore, the U.S. Government has an 

obligation to ensure that the Timbisha Shoshone’s reservation remains livable and selfsustaining and that the tribal springs and groundwater sources remain free of radioactive 

contamination in perpetuity. The commenter further noted that the NRC is obligated to delay 

consideration or approval of the supplement until the Timbisha and the U.S. have fully analyzed 

the potential impacts to lands held in Trust. 

RESPONSE: The NRC staff acknowledges the concerns expressed by the commenter about 

potential impacts to groundwater and springs and cultural resources at discharge locations. The 

potential impacts to water in the Furnace Creek springs are discussed in Section 3.1.2.2 of the 

supplement. These springs provide water to the Timbisha Shoshone reservation in Death 

Valley. The potential concentrations of contaminants at this location are calculated to be very 

low, and the impacts on the aquifer, soil, and public health would be small. 

In addition, Section 3.4.2 of the supplement assesses the potential human health and 

environmental effects that contaminated groundwater from the repository may have on minority 

and low-income populations. The staff assessment includes consideration of impacts to Native 

American communities. As stated in the supplement, the NRC staff determined that the 

proposed repository would not create disproportionate effects on minority and low-income 

populations. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified related to cultural resources and other 

Native American concerns that requires further supplementation of DOE’s 2002 and 2008 EISs 

in the future. The completion of licensing activities, however, is subject to appropriations and 

other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(060) 

B.2.6.1.6. COMMENT: One commenter stated that the Federal Government, including 

DOE and the NRC, needs to stop engaging in “radioactive racism.” The commenter described 

situations in which he believes the U.S. Government unfairly treated Native American tribes with 

regard to Federal projects involving nuclear materials. 

RESPONSE: The NRC staff acknowledges that radiological impacts on Native American 

populations are an environmental justice concern. Section 3.4.2 of the supplement assesses 

the potential human health and environmental effects that contaminated groundwater from the 

repository could have on Native American communities and other minority and low-income 
B–99 

populations. As stated in the supplement, the staff determined that the proposed repository 

would not create disproportionate effects on minority and low-income populations. 

Section 3.2.1.4.3 of the NRC staff’s ADR (NRC, 2008a) notes that DOE committed to work with 

tribes to identify mitigation measures to address tribal perspectives. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified in future tribal consultations that requires 

further supplementation of DOE’s 2002 and 2008 EISs in the future. The completion of 

licensing activities is subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of this comment. 

(095-12) 

B.2.6.1.7. COMMENT: Several commenters asserted that the siting of the Yucca Mountain 

repository was a political decision and they questioned the credibility of decisionmakers who 

designated the Yucca Mountain site. Several commenters indicated that the continued efforts to 

license the Yucca Mountain project are politically or financially motivated. Two commenters 

expressed concern that elected officials received monies from the nuclear industry and they 

believe the NRC is tied too closely to the nuclear industry. One commenter questioned whether 

government officials and scientists have been honest or given correct information about the 

potential effects of nuclear weapons testing and the accidents at Fukushima and Chernobyl on 

human health and the environment. 

RESPONSE: The NRC staff recognizes the difficulties that the U.S. has encountered in 

achieving political and social acceptance in siting and licensing a geologic repository. However, 

these comments, including those concerning national waste disposal policy, are outside the 

scope of the supplement, which concerns an assessment of the potential impacts to 

groundwater and surface discharges of groundwater beyond the postclosure compliance 

location, which is 18 km [11 mi] from the Yucca Mountain project site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The NRC is an independent Federal agency established to ensure the safe use of radioactive 

materials for beneficial civilian purposes while protecting people and the environment. The 

NRC staff’s review of the license application for the proposed repository, including the 

preparation of this supplement, is pursuant to the NWPA. 

The NRC strives to conduct its regulatory responsibilities in an open and transparent manner, 

consistent with the NRC Approach to Open Government. To ensure objectivity and 

independence in its regulatory activities, the NRC and the U.S. Office of Government Ethics 

have stringent rules and procedures to ensure that employees of and advisors to the NRC are 

free of conflicts of interest and the appearance of conflicts of interest. 

No changes were made to the supplement as a result of these comments.

(146-13, 146-18, 147-06, 147-23, 147-25, 149-14) 

B.2.6.1.8. COMMENT: Several commenters raised concerns about the storage of spent 

nuclear fuel on site at nuclear power plants, raising concerns about current storage in spent fuel 
B–100 

pools and in casks. Some commenters expressed concern about storing spent fuel in pools, 

especially for very long timeframes, and a number of people support moving the fuel to dry 

storage. Several commenters support hardened on-site storage (HOSS) for spent fuel storage 

because they believe it would be safer than transporting fuel across the country to 

Yucca Mountain. Commenters also stated the need to store spent fuel in quality, tested dry 

casks. Two commenters opposed centralized storage facilities, with one commenter citing 

problems that occurred at the Waste Isolation Pilot Project. One commenter proposed several 

novel storage techniques that the commenter stated would improve safety. 

Other commenters expressed concerns about the ability of dry casks to maintain adequate 

protection against leakage as a result of degradation, seismic events, or terrorist attacks. Two 

commenters raised questions about the use of dry storage casks that are not supplied by DOE, 

stating that this violates the Standard Contract Agreement for waste acceptance.

RESPONSE: The NRC staff acknowledges the commenters’ concerns regarding onsite 

storage. However, these comments are outside the scope of the supplement, which concerns 

an assessment of the potential impacts to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain 

project site. The scope of this supplement is further described in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The NRC ensures that spent fuel is being stored safely in spent fuel pools and dry casks 

through its regulatory control and oversight of spent fuel storage. Additional information on the 

storage of SNF in spent fuel pools and dry casks is available on the NRC Web site at 

http://www.nrc.gov/waste/spent-fuel-storage.html. 

No changes were made to the supplement as a result of these comments.

(035, 041, 080-06; 080-13, 080-14, 080-17, 086, 095-01, 095-04, 095-06, 095-07, 095-11, 100, 

133, 134, 139, 146-09, 147-15, 149-14) 

B.2.6.1.9. COMMENT: One commenter suggested that information on Yucca Mountain as 

a nuclear waste repository and information relevant to the NRC should be topics included in the 

Engineering Tribute to the Presidential Inauguration of 2017. The commenter offered 

information about the Engineering Tribute and described ways to participate. 

RESPONSE: The NRC staff appreciates the commenter’s recommendation; however, this 

comment is outside the scope of the supplement, which concerns an assessment of the 

potential impacts to groundwater and surface discharges of groundwater beyond the 

postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain project site. 

The scope of this supplement is further described in the NRC’s Notice of Intent to prepare the 

supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

No changes were made to the supplement as a result of this comment.

(080-02, 125) 

B.2.6.1.10. COMMENT: Two commenters stated concerns about the environmental 

contamination of Earth as a whole, suggesting that the problem of nuclear waste is much 

smaller by comparison. 
B–101 

RESPONSE: The NRC staff acknowledges the comments concerning environmental 

contamination and degradation. The comments are general in nature, outside the scope of the 

supplement, which concerns an assessment of the potential impacts to groundwater and 

surface discharges of groundwater beyond the postclosure compliance location, which is 18 km 

[11 mi] from the Yucca Mountain project site. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 

No changes were made to the supplement as a result of these comments. 

(147-02, 147-25) 

B.2.6.1.11. COMMENT: One commenter asked whether NRC and DOE should include a 

discussion of whether the Yucca Mountain repository would be a Superfund site under the 

Comprehensive Environmental Response, Compensation, and Liability Act of 1980.

RESPONSE: The potential for classification of Yucca Mountain as a Superfund site is outside 

the scope of the supplement, which concerns an assessment of the potential impacts to 

groundwater and surface discharges of groundwater beyond the postclosure compliance 

location, which is 18 km [11 mi] from the Yucca Mountain project site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

No changes were made to the supplement as a result of this comment.

(116) 

B.2.6.1.12. COMMENT: One commenter expressed concern about quality control in field 

work to collect data for Yucca Mountain evaluations, stating that core borings were improperly 

collected and labeled. 

RESPONSE: The NRC staff acknowledges the commenter’s concern about the integrity of field 

samples. However, this comment is outside the scope of the supplement, which concerns an 

assessment of the potential impacts to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain 

project site. The scope of this supplement is further described in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The Yucca Mountain site and vicinity has been studied in detail for decades by private 

organizations, as well as local, State, and Federal agencies. The NRC implemented quality 

control programs during its field evaluations for Yucca Mountain. The NRC staff reviewed 

DOE’s quality assurance programs and practices, as discussed in the NRC staff’s SER. 

The NRC staff’s evaluation of DOE’s quality assurance program can be found in its SER 

(NRC, 2014b; Section 2.5.1). 

No changes were made to the supplement as a result of this comment. 

(095-02) 
B–102 

B.2.6.1.13. COMMENT: One commenter recommended that rolling stewardship be 

instituted, instead of disposing of nuclear waste in a repository (i.e., abandoning the waste, 

which the commenter believes is unethical and unscientific). The commenter cited problems 

with cleaning up sites, the lack of certainty in mathematical models that predict performance, 

and historical radiological accidents at reactors and at disposal facilities as reasons for 

instituting rolling stewardship instead of geologic disposal. 

RESPONSE: The NRC staff acknowledges the commenter’s concern regarding long-term 

management of a geologic repository. The NRC does not establish policy for the long-term 

management of spent fuel and HLW in the U.S. This comment is outside the scope of the 

supplement, which concerns an assessment of the potential impacts to groundwater and 

surface discharges of groundwater beyond the postclosure compliance location, which is 18 km 

[11 mi] from the Yucca Mountain project site. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 

No changes were made to the supplement as a result of this comment.

(144) 

B.2.6.1.14. COMMENT: One commenter suggested that a visitors’ center be established at 

the now decommissioned National Rocket Development Station. The commenter also 

suggested the showing of an educational video that illustrates the placement of spent fuel rods 

into canisters to demonstrate the safety of nuclear waste packaging. 

RESPONSE: The NRC staff acknowledges the commenter’s concern about public education 

related to nuclear waste disposal. This comment is outside the scope of the supplement, which 

concerns an assessment of the potential impacts to groundwater and surface discharges of 

groundwater beyond the postclosure compliance location, which is 18 km [11 mi] from the 

Yucca Mountain project site. The scope of this supplement is further described in the NRC’s 

Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). 

More information about the storage of spent nuclear fuel can be found on the NRC’s Web site at 

http://www.nrc.gov/waste/spent-fuel-storage.html. 

No changes were made to the supplement as a result of this comment. 

(147-05) 

B.2.6.1.15. COMMENT: Several commenters stated their concerns about the potential 

dangers of radiation. Some of these commenters expressed their belief that no amount of 

radiation is safe, with some commenters citing studies or other information. Two commenters 

expressed disapproval regarding the cessation of the National Academy of Sciences study 

evaluating the long-term cancer risks to communities near nuclear power plants, stating that 

funding would be well spent on continuation of this study. One commenter expressed concerns 

about the credibility of governing officials and about existing contamination near the 

Yucca Mountain site. 
B–103 

RESPONSE: The NRC staff acknowledges commenters’ concerns about radiation and its 

potential effects on human health and the environment. Concerns about the development of the 

NRC’s radiation protection standards and the cessation of the NAS study are outside the scope 

of the supplement, which concerns an assessment of the potential impacts to groundwater and 

surface discharges of groundwater beyond the postclosure compliance location, which is 18 km 

[11 mi] from the Yucca Mountain project site. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 

The NRC staff agrees that groundwater has been contaminated at the NNSS (formerly the 

Nevada Test Site) and acknowledges commenters’ concerns that it may reach the affected 

environments for the repository. The NRC staff considered cumulative impacts in Chapter 4 of 

the supplement and found these impacts to be small when considering sources from the 

repository and from other sources, including the NNSS. 

The NRC’s mission is to regulate the Nation's civilian use of radioactive materials to protect 

public health and safety, promote the common defense and security, and protect the 

environment. The NRC’s regulatory standards for radiological protection are set to protect 

workers and the public from the harmful health effects (i.e., cancer and other biological impacts) 

of radiation in humans. Radiation standards reflect extensive scientific study by national and 

international organizations. The NRC actively participates in the work of these organizations. 

Additional information about the risks of radiation, including several background information 

sheets, can be found on the NRC’s Web site at http://www.nrc.gov/about-nrc/radiation.html. 

Additional information about the cessation of the National Academy of Sciences Cancer Risk 

Pilot study can be found at http://pbadupws.nrc.gov/docs/ML1525/ML15251A111.pdf. 

No changes were made to the supplement as a result of these comments.

(080-15, 111, 120, 146-01, 147-15, 147-20, 147-23, 149-13, 149-14) 

B.2.6.1.16. COMMENT: Several commenters expressed different views about the siting of 

Yucca Mountain for a repository and about consent in the siting process. Two commenters 

stated that the repository should not be forced on Nevada or its residents, and one commenter 

called for an alternate location. One commenter stated that creating a new Federal authority to 

determine the feasibility of nuclear waste disposal in southern Nevada may facilitate gaining 

Nevada’s consent. One commenter stated that Nevada politicians had previously provided their 

consent, but then withdrew it based on political and financial motivations. Another commenter 

suggested that the lack of consent has hindered the development of Yucca Mountain, but that a 

lack of consent and other difficulties may likewise arise for another site that may be identified. 

Several commenters voiced support for consent-based siting as recommended by the Blue 

Ribbon Commission on America’s Nuclear Future. One commenter questioned the feasibility of 

consent-based siting, stating that the Blue Ribbon Commission’s intent was for an interim 

storage site. This commenter also noted that more spent nuclear fuel exists than could be 

stored in Yucca Mountain. Another commenter stated that consent must be earned, and could 

be earned through scientific studies.

RESPONSE: The NRC staff acknowledges that geologic repository siting has been a subject of 

political and social opposition. The Federal site-selection process is not within the NRC’s 

statutory or regulatory authority and is outside the scope of the supplement, which concerns an 
B–104 

assessment of the potential impacts to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain 

project site. The scope of this supplement is further described in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

DOE responded to the recommendations on repository site selection made in the January 2012 

Blue Ribbon Commission Report on America’s Nuclear Future (BRC, 2012). In January 2013, 

DOE released its Strategy for the Management and Disposal of Used Nuclear Fuel and 

High-Level Radioactive Waste (DOE, 2013b) in response to the Blue Ribbon Commission 

Report. In this document, DOE stated that it planned to move “toward a sustainable program to 

deploy an integrated system capable of transporting, storing, and disposing of used nuclear fuel 

and high-level radioactive waste from civilian nuclear power generation.” Since publication of 

this document, DOE stated that it is developing a consent-based siting process. The NRC staff 

continues to monitor DOE’s efforts. Current information about DOE’s consent-based siting 

process can be found at http://www.energy.gov/ne/consent-based-siting. 

No changes were made to the supplement as a result of these comments. 

(056, 066, 069, 095-09, 100, 147-03, 147-04, 147-09, 147-15, 147-17, 149-06, 149-16) 

B.2.6.1.17. COMMENT: Several commenters suggested alternative technologies or 

solutions for energy generation, and spent nuclear fuel management and disposal. These 

suggestions included transmutation, reduction of waste volumes using laser technology, or 

neutralization of the waste. Other commenters recommended construction of desalination 

plants and pipelines to provide water at a repository, or use of solar or hydroelectric power as 

alternative energy sources. Several commenters recommended that reprocessing be 

implemented, and one commenter stated their opposition to reprocessing. 

RESPONSE: The NRC staff acknowledges the comments calling for alternate energy 

generation and developing spent nuclear fuel management alternatives. However, these 

comments are outside the scope of the supplement, which concerns an assessment of the 

potential impacts to groundwater and surface discharges of groundwater beyond the 

postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain project site. 

The scope of this supplement is further described in the NRC’s Notice of Intent to prepare the 

supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

No changes were made to the supplement as a result of these comments. 

(066, 069, 080-01, 087, 091, 095-06, 100, 103, 127, 147-02, 147-05, 147-20, 149-14) 

B.2.6.1.18. COMMENT: Several commenters urged continuation and completion of the 

licensing process, with some commenters requesting that the NRC seek funding from Congress 

to facilitate completion of the licensing process. Commenters noted that a repository is needed 

because of spent nuclear fuel accumulation around the country and because legal and 

contractual obligations under the Nuclear Waste Policy Act are not being met. 

RESPONSE: The NRC staff acknowledges the comments regarding further activities in the 

licensing process and the availability of funding. These comments outside the scope of the 

supplement, which concerns an assessment of the potential impacts to groundwater and 

surface discharges of groundwater beyond the postclosure compliance location, which is 18 km 
B–105 

[11 mi] from the Yucca Mountain project site. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 

The Commission directed the NRC staff to complete the supplement to DOE’s EISs, along with 

other tasks, following the decision in 2013 by the Court of Appeals for the District of Columbia 

Circuit. The preparation of this supplement is one of several steps in the licensing process for 

the proposed repository. The completion of licensing activities is subject to appropriations and 

other actions external to the NRC. 

No changes were made to the supplement in response to these comments. 

(051, 068, 135, 143, 145, 149-05) 

B.2.6.1.19. COMMENT: Several commenters made statements in support of nuclear power. 

Some of the commenters cited the lack of greenhouse gas emissions and concerns about the 

effects of other power sources on global climate change and land use. One commenter stated 

that the problem of spent fuel disposal hinders the further expansion of nuclear power.

RESPONSE: Comments regarding the use of nuclear power are outside the scope of the 

supplement, which concerns an assessment of the potential impacts to groundwater and 

surface discharges of groundwater beyond the postclosure compliance location, which is 18 km 

[11 mi] from the Yucca Mountain project site. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 

The NRC is an independent regulator that does not promote nuclear or other types of energy. 

The NRC regulates commercial nuclear power plants, including the management of commercial 

spent nuclear fuel, and other civilian uses of nuclear materials, such as nuclear medicine, 

through licensing, inspection, and enforcement of its requirements. 

No changes were made to the supplement as a result of these comments. 

(038, 095-03, 126, 147-02, 147-25, 149-07, 149-16) 

B.2.6.1.20. COMMENT: Several commenters raised questions or concerns about the water 

and land rights that DOE would need to secure to receive a construction authorization for a 

repository at Yucca Mountain. Some of these commenters said that the project cannot or 

should not be licensed or further considered because the NRC’s SER concluded that DOE has 

not yet obtained all the proper land or water rights required to license the project. One of the 

commenters contended that the supplement is insufficient because land and water rights were 

not included in the analysis. Another commenter noted that DOE does not have the proper rail 

access. One commenter also raised a concern about the tribal ownership of the land. 

RESPONSE: The NRC staff acknowledges the commenters’ concerns about land ownership, 

water rights and rail access for the construction and operation of a repository at 

Yucca Mountain. These topics are outside the scope of the supplement, which concerns an 

assessment of the potential impacts to groundwater and surface discharges of groundwater 
B–106 

beyond the postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain 

project site. The scope of this supplement is further described in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

As discussed in the supplement (Chapter 1), this environmental analysis is based upon DOE’s 

application, including its Safety Analysis Report (DOE, 2008b). The NRC staff’s review of land 

ownership and water rights at the proposed Yucca Mountain repository is discussed in its SER 

(NRC, 2014b, Chapter 11, Section 2.5.8). 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. As discussed in Section 1.1 of the supplement, the adjudicatory 

proceeding for the proposed repository is currently suspended. The completion of licensing 

activities is subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(021, 034, 056, 074, 117, 147-03, 147-04, 147-08, 147-09, 148, 149-17) 

B.2.6.1.21. COMMENT: Several commenters expressed concern about potential future 

funding and funding mechanisms for the Yucca Mountain project. Several commenters stated 

the nuclear industry should be responsible for the total costs of nuclear waste disposal. Other 

commenters stated the high costs of disposal creates an undue burden on taxpayers. 

Commenters also asserted that the full cost of the repository is difficult to calculate because 

Nevada anticipates delays due to years of litigation, and problems may arise in the future. 

Several commenters stated their opposition to the Price-Anderson Act, calling for it to be 

revoked and stating that the nuclear industry should be liable for nuclear accidents. One 

commenter stated that nuclear industry should not fund the campaigns of elected officials or hire 

former government workers because these actions create conflicts of interest. Other 

commenters pointed out that Congress has not appropriated funds to continue the 

Yucca Mountain repository licensing process in several years. They questioned whether funds 

will ever be made available, given the high cost of the facility, the shortage of funding for other 

public projects, and stakeholder opposition to the repository. A few commenters stated that 

even if Congress appropriated funds, the repository project would not bring revenues to nearby 

communities. One commenter also stated that monies from the Nuclear Waste Fund should not 

be used to fund an interim storage site. 

RESPONSE: The NRC staff acknowledges that the NRC has limited funds available to 

complete the Yucca Mountain license application review. Comments regarding funding for the 

Yucca Mountain project or for NRC license review activities, financial liability, campaign funding, 

and industry hiring practices are outside the scope of the supplement, which concerns an 

assessment of the potential impacts to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain 

project site. The scope of this supplement is further described in the NRC’s Notice of Intent to 

prepare the supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The 2013 decision by the Court of Appeals for the District of Columbia Circuit ordered the NRC 

to resume work on licensing activities as long as the agency had available funds from previous 
B–107 

appropriations. Following the NRC staff’s publication of the SER, sufficient funds remained for 

the NRC staff to develop this supplement. The completion of licensing activities, however, is 

subject to further appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(002, 095-10, 095-11, 098, 100, 102, 146-03, 146-13, 147-03, 147-06, 147-15, 149-20) 

B.2.6.1.22. COMMENT: Many commenters stated concerns about the transportation of 

nuclear waste to a repository at Yucca Mountain. Several commenters opposed any 

transportation of radioactive materials (by air, barge, roads, or rail). Many of the commenters 

stated concerns about potential radiation exposure to citizens and transportation workers and to 

watersheds and land areas adjacent to railways, waterways, and roadways during the transport 

of spent fuel, as well as from accidents during transportation. 

One commenter felt that storage at existing nuclear power plant sites is the safest option. 

Commenters also raised concerns about the structural integrity of casks, canisters, and spent 

fuel assemblies before and during shipment, and during unloading. Several commenters 

questioned the bases underlying the models assessing cask damage in accident and sabotage 

situations. Many commenters raised concerns about the preparedness of emergency 

responders in accident situations. Others questioned whether casks can be so damaged as to 

hinder safe retrieval. The commenters cited the need to properly evaluate accident scenarios to 

assess the containment integrity of casks, the potential for high-temperature fire damage to 

casks, and the effects of aging on some parts of the national transportation infrastructure. 

Other commenters requested casks’ integrity be assessed for a possible terrorist attack or 

sabotage. Some of the commenters stated various reasons for their concern—including other 

nonradioactive transportation accidents and shipment experience in other countries, such as 

accidents involving the rail transportation of oil or other toxic or flammable substances—and 

expressed skepticism about claims that humans have not been harmed as a result of the 

transportation of nuclear materials historically. 

RESPONSE: The NRC staff acknowledges the concerns about the transportation of radioactive 

waste and transportation accidents. These comments are outside the scope of the supplement, 

which concerns an assessment of the potential impacts to groundwater and surface discharges 

of groundwater beyond the postclosure compliance location, which is 18 km [11 mi] from the 

Yucca Mountain project site. The scope of this supplement is further described in the NRC’s 

Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s ADR 

(NRC, 2008a). 

Regulatory oversight of radioactive materials shipments is the joint responsibility of the NRC 

and the U.S. Department of Transportation (DOT). The NRC oversees the safety of the 

transportation of nuclear materials through a combination of regulatory requirements, 

transportation package certification, inspections, and a system of monitoring to ensure that 

safety requirements are being met. Information about NRC regulation for these and other 

aspects of radioactive materials transportation can be found at http://www.nrc.gov/waste/spentfuel-transp.html. The DOT has regulatory oversight for shipments while they are in transit. 

Comments related to transportation are addressed further in Section B.2.4.6.6 of this appendix. 
B–108 

No changes have been made to the supplement as a result of these comments. 

(004, 012, 016, 025, 030, 032, 033, 034, 080-03, 080-13, 084, 086, 095-02, 095-04, 095-05, 

095-07, 095-08, 095-10, 097, 098, 109, 117, 139, 146-08, 146-12, 146-18, 147-03, 147-04, 147-

07, 147-19, 149-09)

B.2.6.1.23. COMMENT: Several commenters stated their concern about the use, storage, 

and transportation of high-burnup fuel. Two commenters expressed concern about the lack of 

data to assess or mitigate the degradation of high-burnup spent fuel cladding. The commenters 

stated that properties of high-burnup fuel, such as the higher possibility of embrittlement in 

cladding, creates significant implications for storage in pools, movement of the fuel to dry 

storage, or transportation. One commenter called for the cessation of the use and NRC 

approval of high-burnup fuel and for rejection of NUREG-2125, “Spent Fuel Transportation Risk 

Assessment,” for failing to consider high-burnup spent fuel (NRC, 2014c). Two commenters 

stated that no casks have been approved for transportation of high-burnup spent fuel; and 

therefore, the assumption that casks will exist to transport this fuel is invalid. 

RESPONSE: Comments about the use, storage, and transportation of high-burnup fuel are 

outside the scope of the supplement, which concerns an assessment of the potential impacts to 

groundwater and surface discharges of groundwater beyond the postclosure compliance 

location, which is 18 km [11 mi] from the Yucca Mountain project site. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The NRC staff acknowledges that high-burnup fuels are of concern to some stakeholders. The 

NRC continues to monitor international and national efforts to conduct research on high-burnup 

fuels, including degradation mechanisms, and is currently funding its own studies on highburnup fuel, although the NRC staff notes that it has certified casks for the transportation and 

storage of high-burnup fuels. Additional information about the NRC’s regulatory activities 

related to high-burnup fuels can be found at http://www.nrc.gov/reading-rm/doc-collections/factsheets/bg-high-burnup-spent-fuel.html. 

No changes were made to the supplement as a result of these comments. 

(016, 072, 146-01) 

B.2.6.2 General Opposition 

B.2.6.2.1. COMMENT: Several commenters expressed general concerns that there is 

currently no viable solution to the long-term management or disposal of spent nuclear fuel, and 

that radiological materials (including radioactive waste) are dangerous. The commenters cited 

historical and current issues at sites containing radiological materials, such as the NNSS, the 

Hanford site, and the Waste Isolation Pilot Project disposal site. Some of the commenters 

stated the need for robust scientific solutions for nuclear waste disposal. 

RESPONSE: The NRC staff acknowledges that difficulties have been encountered at the sites 

identified by the commenters. The evaluation of other long-term radioactive waste management 

and disposal options is outside the scope of the supplement, which concerns an assessment of 

the potential impacts to groundwater and surface discharges of groundwater beyond the 
B–109 

postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain project site. 

The scope of this supplement is further described in the NRC’s Notice of Intent to prepare the 

supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

Comments addressing alternate solutions for nuclear waste, identifying the historical difficulties 

experienced at military nuclear facilities, or remarking on nonnuclear issues that occurred at the 

Waste Isolation Pilot Plant, however, are also beyond the scope of this supplement. 

Likewise, comments stating that a viable solution for long-term management or disposal of 

spent nuclear fuel are also outside the scope of this supplement. The NRC staff’s SER for the 

Yucca Mountain repository and the Continued Storage GEIS (NUREG-2157) provide recent 

NRC analyses on these subjects. 

No changes were made to the supplement as a result of these comments. 

(095-06, 095-08, 095-10, 146-05, 147-15, 149-13) 

B.2.6.2.2. COMMENT: Commenters expressed general disagreement with the approach, 

the scope, the information collection methods, and the conclusions reached in the NRC staff's 

supplement and called for withdrawal of the document. Some commenters provided specific 

reasons for their disagreement with the supplement. A few commenters stated that the 

supplement is deficient because the analyses rely on incomplete or inaccurate information. 

They also asserted that the supplement does not adequately characterize potential impacts 

from accidents, surface discharges of groundwater in the Amargosa Desert, transportation 

routes, and seismic activity. Three commenters stated that Native American communities in the 

Middle Amargosa Basin, specifically the towns of Shoshone and Tecopa, and the Timbisha 

Shoshone Tribe community in Death Valley, have not been fully analyzed in either the NRC’s 

supplement or DOE's EIS documents. Several commenters question the supplement’s 

conclusions and call for additional scientific studies and tribal consultations. 

RESPONSE: The NRC staff acknowledges the commenters’ general disagreement with the 

nature of the supplement and its scope. Many of these comments are general or broadly 

question the basis for various assumptions or attributes of the analysis. The subject areas 

discussed generally by these commenters are addressed in greater detail in response to other 

comments throughout this appendix. Comments on Native American communities are 

addressed in Section B.2.4.2.3, B.2.4.4, and B.2.4.5; comments on groundwater resources and 

impacts are addressed in Sections B.2.3.2 and B.2.4.1; comments on transportation are 

addressed in Section B.2.4.6.6; and comments on seismicity are addressed in 

Sections B.2.4.6.7 and B.2.4.6.8. Comments about the accuracy and completeness of 

information and the assumptions are addressed in Section B.2.1.2 and B.2.2, respectively. 

No changes were made to the supplement as a result of these comments. 

(006, 060, 061, 062, 095-05, 095-10, 107, 108, 119, 124, 133, 134, 147-19, 149-10) 

B.2.6.2.3. COMMENT: Several commenters stated the NRC should withdraw or stop work 

on the supplement, because Yucca Mountain is an unsuitable location for a repository. 

Furthermore, they stated that continuing work on it is not a useful expenditure of time or 

financial resources. A number of commenters pointed out that Federal funds have not been 

appropriated for completion of the Yucca Mountain licensing. Several commenters stated that 

rather than using financial resources to complete the supplement or to continue to develop the 
B–110 

Yucca Mountain repository, funds should be spent on workable solutions to store spent nuclear 

fuel and HLRW or on socially-oriented programs. Commenters also cited concerns about 

potential health effects from radioactive materials, and objected to expediting the supplement at 

the expense of accurate factual information. Commenters also expressed concern about the 

role of politics in the overall Yucca Mountain repository process. 

RESPONSE: Comments opposing a repository at Yucca Mountain because of financial and 

social considerations are outside the scope of the supplement, which concerns an assessment 

of the potential impacts to groundwater and surface discharges of groundwater beyond the 

postclosure compliance location, which is 18 km [11 mi] from the Yucca Mountain project site. 

The scope of this supplement is further described in the NRC’s Notice of Intent to prepare the 

supplement (80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(015, 027, 034, 056, 074, 111, 147-03, 147-04, 147-08, 147-09, 147-19, 148) 

B.2.6.2.4. COMMENT: Commenters expressed broad opposition to the generation of 

nuclear waste and the continuation of nuclear power generation in the U.S. Many of the 

commenters stated that the U.S. should end the nuclear generation of electricity in order to stop 

producing spent nuclear fuel, because there is currently no solution for the waste. Some 

comments raised concerns about health risks and called for the shutdown of all nuclear power 

reactors and a moratorium on the construction of new nuclear plants. Other commenters 

referred to international radiological accidents and the accident at the Waste Isolation Pilot 

Plant. One commenter stated that the NRC should take its role of protecting the public more 

seriously. Other commenters expressed concern for the Earth and protecting future generations 

from nuclear waste. 

RESPONSE: The NRC staff acknowledges the comments raising general opposition to nuclear 

power, but notes that these comments are outside the scope of the supplement, which concerns 

an assessment of the potential impacts to groundwater and surface discharges of groundwater 

beyond the postclosure compliance location. The scope of this supplement is further described 

in the NRC’s Notice of Intent to prepare the supplement (80 FR 13029) and in the NRC staff’s 

ADR (NRC, 2008a). 

Further, the NRC is an independent regulator that does not promote nuclear or other types of 

energy. The NRC was created to ensure the safe use of radioactive materials for beneficial 

civilian purposes while protecting people and the environment. The NRC regulates commercial 

nuclear power plants and other uses of nuclear materials, such as in nuclear medicine, through 

licensing, inspection, and enforcement of its requirements. 

No changes were made to the supplement as a result of these comments. 

(009, 011, 012, 023, 041, 048, 058, 062, 077, 080-01, 080-09, 080-11, 080-12, 080-13, 080-15, 

090, 095-05, 095-06, 095-11, 097, 100, 102, 105, 109, 146-16, 147-16, 147-20, 149-15) 
B–111 

B.2.6.2.5. COMMENT: Many commenters opposed the siting and operation of a repository 

at Yucca Mountain and stated various general reasons for their opposition. Commenters cited 

concerns about public health and safety, about whether the repository can adequately contain 

radioactive waste, that the State of Nevada and its residents have not consented to the siting of 

the facility, and that repository siting should be consent-based. Other commenters stated that 

DOE’s plan is unworkable and represents a misuse of public resources. Several commenters 

opposed the decisionmaking process that designated the Yucca Mountain site as the repository 

location. A few commenters stated that the NRC is conspiring with the nuclear industry in 

evaluating Yucca Mountain for repository siting. Several commenters rejected the scientific and 

engineering studies and analyses conducted by DOE and the NRC. Some commenters 

asserted that these agencies misunderstand the technical issues or that information about 

Yucca Mountain has been misrepresented. Commenters generally questioned the accuracy 

and reliability of the long-term modeling underlying the environmental and safety conclusions 

made by DOE and the NRC. Other commenters opposed the project because of concerns 

about the ability to safely transport spent fuel and radiological materials to the repository. One 

commenter questioned the NRC staff’s SER finding that the repository meets applicable 

performance standards and regulatory requirements and will protect public health and safety. 

RESPONSE: The NRC staff acknowledges the comments opposing a repository at Yucca 

Mountain; however, these comments are beyond the scope of this supplement, which concerns 

an assessment of the potential environmental impacts to groundwater and from surface 

discharges of groundwater beyond the postclosure compliance location. The scope of this 

supplement is further described in the NRC’s Notice of Intent to prepare the supplement 

(80 FR 13029) and in the NRC staff’s ADR (NRC, 2008a). 

The SER and EIS supplement reflect the NRC staff’s independent safety evaluations and 

analyses of DOE’s license application and an assessment of DOE’s environmental review. 

Commenters’ concerns about transportation are discussed in Section B.2.4.6.6 and B.2.6.1.22. 

The preparation and publication of this supplement is one of several steps in the licensing 

process for the proposed repository. Information may be identified that requires further 

supplementation of DOE’s 2002 and 2008 EISs in the future. The completion of licensing 

activities is subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(002, 012, 021, 026, 029, 034, 044, 045, 048, 050, 052, 057, 059, 065, 066, 072, 074, 078, 079, 

080-01, 080-06, 080-09, 080-10, 080-17, 081, 088, 089, 091, 095-06, 095-07, 095-08, 095-11, 

098, 100, 102, 107, 108, 109, 114, 116, 117, 121, 127, 128, 134, 139, 144, 146-01, 146-13, -

146-16, 146-17, 146-18, 147-03, 147-04, 147-06, 147-07, 147-08, 147-15, 147-16, 147-18, 147-

27, 148, 149-14, 149-15, 149-20, 149-21)

B.2.6.3 General Support 

B.2.6.3.1. COMMENT: Several commenters expressed general support for the 

development of the supplement, or endorsed the conclusions in the supplement. Commenters 

stated that the NRC’s findings were consistent with the scientific and environmental studies 

produced by Federal and State agencies and that the NRC used conservative assumptions in 

estimating environmental impacts, especially in estimating annual radiological dose. 
B–112 

Commenters supported the NRC’s findings that all of the impacts on the resources evaluated 

within would be small, including potential impacts on groundwater and from groundwater 

discharges of groundwater, stating that the supplement complies with all NEPA requirements. 

Some commenters expressed support for the NRC’s decision to develop the supplement in light 

of DOE’s decision not to. Others commented on the thoroughness of the draft supplement, that 

the NRC’s public involvement process was fair, and that the supplement demonstrates the 

technical feasibility of the Yucca Mountain repository. One commenter stated that the 

supplement scope was appropriate, properly focused on groundwater issues, and 

complemented DOE’s environmental reports. 

Some of these comments in support of the supplement also expressed general support for siting 

the repository at Yucca Mountain, arguing that the decision to license the repository should be 

based on science, which the commenter stated supports development of the project. 

Commenters also noted that the findings in the supplement support the NRC staff’s SER 

conclusions that regulatory requirements would be met and provide further evidence that spent 

nuclear fuel and HLRW can be disposed of safely in a geologic repository at Yucca Mountain. 

Several commenters expressed confidence that the completion of the supplement would result 

in completion of a repository at Yucca Mountain. Some of these commenters urged the NRC to 

move forward with the licensing process under the Nuclear Waste Policy Act. 

RESPONSE: The NRC staff acknowledges the comments stating general support for the 

development of the supplement and endorsing the conclusions in the supplement. The NRC 

staff agrees that conservative assumptions were used, that the supplement scope is 

appropriate, the supplement complies with NEPA, and that the conclusions reached in the 

supplement support the NRC staff’s findings in the SER. The preparation of this supplement is 

one of several steps in the licensing process for the proposed repository. The completion of 

licensing activities is subject to appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(005, 046, 051, 068, 135, 138, 143, 145, 147-05, 147-17, 149-05, 149-11, 149-18) 

B.2.6.3.2. COMMENT: Several commenters expressed support for the Yucca Mountain 

project for a variety of reasons. Some commenters stated that disposing of spent nuclear fuel in 

a repository at Yucca Mountain is safer and more secure than storing the spent fuel at 

temporary storage facilities around the country, including in spent fuel pools and in dry casks. 

Several commenters expressed confidence in the safety and security of the proposed repository 

at Yucca Mountain, noting that the conclusions reached in the NRC staff’s SER and the EIS 

supplement demonstrate its technical feasibility and safety. Commenters stated that Yucca 

Mountain was a preferred site for a repository for several reasons, including low groundwater 

flow or infiltration, the location of the repository away from water tables, low amounts of potential 

contamination compared to other sources, and the low potential for spills on site. Some 

commenters also stated that groundwater flowing in the area of the Yucca Mountain site is 

already contaminated by activities associated with the NNSS, and, therefore, Yucca Mountain, 

rather than an alternative uncontaminated site, should be the repository site. One commenter 

stated that a repository would provide good jobs in southern Nevada. Some of the commenters 

expressed support for the licensing process to continue, with two commenters noting that, by 

law, the process must be continued or that legal obligations are not being met. 
B–113 

RESPONSE: The NRC staff acknowledges the comments in support of siting and developing a 

repository at Yucca Mountain. The NRC staff concluded in its SER that DOE’s repository 

design meets the performance objectives to isolate radioactivity from the environment, as 

required by 10 CFR Part 63, Subpart E. The NRC staff also found that the proposed repository 

design meets the NRC’s postclosure public and environmental standards for individual 

protection, human intrusion, and groundwater protection, as required by 10 CFR Part 63, 

Subpart L. 

The preparation of this supplement is one of several steps in the licensing process for the 

proposed repository. Information may be identified that requires further supplementation of 

DOE’s 2002 and 2008 EISs in the future. The completion of licensing activities is subject to 

appropriations and other actions external to the NRC. 

No changes were made to the supplement as a result of these comments. 

(007, 037, 038, 051, 069, 080-02, 080-03, 080-14, 125, 147-05, 147-11, 147-25, 147-26, 

149-05, 149-07, 149-16, 149-19) 

B.3 List of Commenters 

Table B–3 lists individuals who provided comments on the draft supplement orally at meetings 

or through comment letters. 

Table B-3. Individuals Who Submitted Written or Oral Comments 

Commenter Affiliation and Title

(if provided) 

Document 

Identification 

Number 

ADAMS 

Accession 

Number 

Anderson, Dorothy Private Citizen 004 ML15343A213 

Andrews, RD Private Citizen 080-14 ML15294A368 

Anonymous Private Citizen 006 ML15343A017 

Anonymous, Susan Private Citizen 008 ML15343A211 

Anonymous Private Citizen 010 ML15343A214 

Anonymous Private Citizen 011 ML15343A422 

Anonymous Private Citizen 016 ML15344A301 

Anonymous Private Citizen 017 ML15344A302 

Ashby, Kylee Private Citizen 007 ML15313A016 

Azarovitz, Janet Private Citizen 009 ML15342A115 

Barnes, Kathryn Private Citizen 012 ML15323A408 

Bechtel, Dennis Private Citizen 018 ML15313A007 

Bechtel, Dennis Private Citizen 019 ML15343A390 

Bechtel, Dennis Private Citizen 147-24 ML15268A399 

Belaski-Ashe, Meghan Private Citizen 021 ML15343A384 

Bell, Kevin California Energy Commission, 

Senior Staff Counsel 147-13 ML15268A399 

Bosold, Patrick Private Citizen 001 ML15292A135 

Bosold, Patrick Private Citizen 002 ML15292A172 

Bosold, Patrick Private Citizen 112 ML15343A018 

Bosta, John Private Citizen 149-17 ML15274A168 

Boudart, Jan Nuclear Energy Information 

Service of Chicago 025 ML15344A205 
B–114 

Table B-3. Individuals Who Submitted Written or Oral Comments 

Commenter Affiliation and Title

(if provided) 

Document 

Identification 

Number 

ADAMS 

Accession 

Number 

Boudart, Jan Nuclear Energy Information 

Service of Chicago 030 ML15344A206 

Boudart, Jan Nuclear Energy Information 

Service of Chicago 032 ML15344A207 

Boudart, Jan Nuclear Energy Information 

Service of Chicago 033 ML15344A216 

Boudart, Jan Nuclear Energy Information 

Service of Chicago 095-04 ML15321A414 

Brechin, Vernon Private Citizen 027 ML15343A028 

Bromm, Susan EPA Office of Federal Activities, 

Director 137 ML15336A983 

Brown, D. Private Citizen 150 ML16013A310 

Bryan, Richard Nevada Commission on Nuclear 

Projects, Chairman 147-06 ML15268A399 

Burton, Vic Private Citizen 028 ML15344A217 

Campbell, Bruce Private Citizen 128 ML15344A095 

Canfield, Skip and Nevada Division of State Lands, 

Program Manager 

136 ML15299A093 

Ernstein, Julie 

Nevada State Historic Preservation 

Office (SHPO), 

Deputy State Historic 

Preservation Officer 

Carpenter, Susan Cape Downwinders 080-06 ML15294A368 

Carpenter, Susan Cape Downwinders 095-08 ML15321A414 

Carrigan, Milton Private Citizen 042 ML15344A272 

Cartwright, Lorie New England Coalition 095-09 ML15321A414 

Ciaran, C. Private Citizen 058 ML15343A383 

Cobb, Sandra Private Citizen 003 ML15292A096 

Cobb, Sandra Private Citizen 063 ML15343A021 

Collins, William Private Citizen 064 ML15343A015 

Corry, Ronit Private Citizen 065 ML15323A405 

Craig, Anne Private Citizen 077 ML15292A132 

Crater, Bruce Private Citizen 149-19 ML15274A168 

Crawford, Amena Private Citizen 066 ML15323A407 

D, Capt Private Citizen 035 ML15343A387 

D'Arrigo, Diane Nuclear Information and 

Resource Service 146-01 ML15253A669 

Damele, Ronald Eureka County (Nevada), 

Public Works Director 118 ML15324A254 

Darby, Forrest Private Citizen 147-25 ML15268A399 

Diamond, Brenda Private Citizen 149-04 ML15274A168 

Dirsa-DuBois, Margaret Private Citizen 113 ML15342A116 

Donnelly, Patrick Amargosa Conservancy, 

Executive Director 149-10 ML15274A168 
B–115 

Table B-3. Individuals Who Submitted Written or Oral Comments 

Commenter Affiliation and Title

(if provided) 

Document 

Identification 

Number 

ADAMS 

Accession 

Number 

Dubois, Gwen Chesapeake Physicians for 

Social Responsibility 146-12 ML15253A669 

Edwards, Gordon Canadian Coalition for Nuclear 

Responsibility, President 144 ML15344A096 

Erquiaga, Carl Churchill County (Nevada), 

Vice-Chairman and Commissioner 046 ML15324A255 

Esteve, Gregory Private Citizen 117 ML15323A404 

Evans, Matthew Private Citizen 119 ML15313A019 

Farber, Joan Private Citizen 078 ML15275A161 

Feldman, Jane Sierra Club, Toiyabe Chapter, 

Energy Committee Chair 129 ML15313A011 

Fettus, Geoffrey Natural Resources Defense Council,

 Senior Attorney 132 ML15344A172 

Fields, Sarah Uranium Watch 080-08 ML15294A368 

Forbes, Melinda Private Citizen 114 ML15344A169 

Foster, Beverly Private Citizen 079 ML15275A158 

Frank, Fred Private Citizen 015 ML15292A133 

Freelain, Kenneth International Definition 080-02 ML15294A368 

Freelain, Kenneth International Definition 095-03 ML15321A414 

Freelain, Kenneth International Definition 125 ML15313A014 

Freelain, Kenneth International Definition 126 ML15336A941 

Gaddis, Nicollee 

Bureau of Land Management, 

Planning and Environmental 

Coordinator 

020 ML15287A395 

Gardner, Rose Private Citizen 080-12 ML15294A368 

Gedicks, Al Private Citizen 022 ML15343A385 

Gholson, George Timbisha Shoshone Tribal Council, 

Chairman 052 ML15313A006 

Gholson, George Timbisha Shoshone Tribal Council, 

Chairman 060 ML15337A078 

Gibson, Kenneth Private Citizen 023 ML15342A118 

Giese, Mark Private Citizen 029 ML15313A018 

Giese, Mark Private Citizen 031 ML15343A419 

Gilmore, Donna San Onofre Safety 146-09 ML15253A669 

Goedhart, Ed Private Citizen 149-13 ML15274A168 

Goodman, Carolyn City of Las Vegas, Mayor 034 ML15313A010 

Goodman, Carolyn City of Las Vegas, Mayor 147-04 ML15268A399 

Gotsch, Paula Private Citizen 146-05 ML15253A669 

Gotsch, Paula Private Citizen 080-09 ML15294A368 

Graham, Darlene Private Citizen 036 ML15344A204 

Gran, Gerhard Private Citizen 037 ML15313A012 

Gran, Gerhard Private Citizen 038 ML15303A254 

Gran, Gerhard Private Citizen 149-07 ML15274A168 

Graves, Caryn Private Citizen 039 ML15292A170 

Graves, Caryn Private Citizen 040 ML15342A117 
B–116 

Table B-3. Individuals Who Submitted Written or Oral Comments 

Commenter Affiliation and Title

(if provided) 

Document 

Identification 

Number 

ADAMS 

Accession 

Number 

Gray, Erica Private Citizen 041 ML15344A170 

Gray, Erica Private Citizen 146-16 ML15253A669 

Grecheck, Eugene American Nuclear Society, 

President 005 ML15343A382 

Hadeck, Jim Private Citizen 147-26 ML15268A399 

Halstead, Robert Nevada Agency for Nuclear Projects,

Executive Director 110 ML15243A454 

Halstead, Robert Nevada Agency for Nuclear Projects, 

Executive Director 147-01 ML15268A399 

Halstead, Robert Nevada Agency for Nuclear Projects, 

Executive Director 149-01 ML15274A168 

Halstead, Robert Nevada Agency for Nuclear Projects, 

Executive Director 149-20 ML15274A168 

Halstead, Robert; Nevada Agency for Nuclear Projects, 

Executive Director 

148 ML15342A010 

Sandoval, Brian; State of Nevada, 

Governor 

Drozdoff, Leo; Nevada Department of Conservation 

and Natural Resources, Director 

Gholson, George; and Timbisha Shoshone Tribe, Chairman 

Zabarte, Ian Government of Newe Sogobia, 

Principal Man for Foreign Affairs 

Harrison, Randy Private Citizen 096 ML15342A114 

Hart, Joshua Inyo County (California), 

Planning Director 130 ML15275A159 

Hays, Helen Private Citizen 097 ML15323A410 

Headington, Maureen Stand Up Save Lives 095-10 ML15321A414 

Headington, Maureen Stand Up Save Lives 098 ML15344A219 

Headington, Maureen Stand Up Save Lives 146-13 ML15253A669 

Hodin, Russell Private Citizen 099 ML15344A218 

Hoffman, Ace Private Citizen 080-15 ML15294A368 

Hoffman, Ace Private Citizen 095-06 ML15321A414 

Hoffman, Ace Private Citizen 100 ML15343A389 

Hoffman, Ace Private Citizen 146-14 ML15253A669 

Hoffman, Ace Private Citizen 147-15 ML15268A399 

Hoffman, Ace Private Citizen 149-14 ML15274A168 

Hoffman, Sharon Private Citizen 147-16 ML15268A399 

Hoffman, Sharon Private Citizen 149-15 ML15274A168 

Hofford, William Private Citizen 104 ML15343A019 

Hofmann, Sarah Nuclear Waste Strategy Coalition, 

Chair 135 ML15342A006 

Hollis, Gary Private Citizen 106 ML15313A008 

Hollis, Gary Private Citizen 149-02 ML15274A168 

Hollis, Gary Private Citizen 149-16 ML15274A168 

Hommel, Teresa Private Citizen 107 ML15343A381 
B–117 

Table B-3. Individuals Who Submitted Written or Oral Comments 

Commenter Affiliation and Title

(if provided) 

Document 

Identification 

Number 

ADAMS 

Accession 

Number 

James, HJ Private Citizen 139 ML15299A099 

Jensen, Pia Private Citizen 081 ML15343A212 

Jessee, Judy Private Citizen 082 ML15292A171 

Jessler, Darynne Private Citizen 083 ML15342A009 

Jim, Eddie Pahrump Paiute Tribe, Chairman 147-22 ML15268A399 

Johnson, Abby Eureka County 146-10 ML15253A669 

Kamps, Kevin Beyond Nuclear 080-16 ML15294A368 

Kamps, Kevin Beyond Nuclear 095-12 ML15321A414 

Kamps, Kevin Beyond Nuclear 146-07 ML15253A669 

Kasenow, Lisa Private Citizen 084 ML15336A976 

Keegan, Michael Don't Waste Michigan 146-04 ML15253A669 

Keegan, Michael Don't Waste Michigan 080-17 ML15294A368 

Kellen, Leonard Private Citizen 080-11 ML15294A368 

Kennedy, Joe Private Citizen 147-20 ML15268A399 

King, Mary Private Citizen 149-12 ML15274A168 

Kingsley, Matt Inyo County (California) Board of 

Supervisors, Chairperson 142 ML15342A025 

Kirschling, Karen Private Citizen 085 ML15342A196 

Kizzia, Toni Private Citizen 149-21 ML15274A168 

Klevorick, Phil Clark County Nuclear Waste Division 147-14 ML15268A399 

Kreisler, Leonard Private Citizen 147-05 ML15268A399 

Lacy, Darrell 

Nye County Nuclear Waste 

Repository Project Office, 

Director 

149-08 ML15274A168 

Ladeira, Amber Private Citizen 080-13 ML15294A368 

LaForge, John Nukewatch, 

Co-Director 086 ML15336A981 

LaForge, John Nukewatch, 

Co-Director 095-01 ML15321A414 

Lazarus, Jay Ponderosa Dairy, 

Consultant 049 ML15342A007 

Leshinskie, Tony 

Vermont Department of Public 

Service, 

State Nuclear Engineer 

146-11 ML15253A669 

Leneman, Cecile Private Citizen 120 ML15342A197 

Levin, Carol Private Citizen 121 ML15343A388 

Lewis, Marvin Private Citizen 080-07 ML15294A368 

Lewis, Marvin Private Citizen 095-02 ML15321A414 

Lewis, Marvin Private Citizen 122 ML15336A980 

Lewis, Marvin Private Citizen 146-08 ML15253A669 

Lingenfelter, Andrew Private Citizen 147-29 ML15268A399 

Lingenfelter, Andrew Private Citizen 149-06 ML15274A168 

Lish, Christopher Private Citizen 101 ML15343A215 

Mack, Webster Private Citizen 103 ML15292A137 

Mack, Webster Private Citizen 147-02 ML15268A399 
B–118 

Table B-3. Individuals Who Submitted Written or Oral Comments 

Commenter Affiliation and Title

(if provided) 

Document 

Identification 

Number 

ADAMS 

Accession 

Number 

Macks, Vic Private Citizen 102 ML15344A271 

Macks, Vic Private Citizen 105 ML15343A026 

Mahowald, Philip Prairie Island Indian Community, 

General Counsel 051 ML15344A173 

Malsch, Marty Egan, Fitzpatrick, Malsch, & 

Lawrence PLLC 141 ML15292A094 

Malsch, Marty Egan, Fitzpatrick, Malsch, & 

Lawrence PLLC 146-06 ML15253A669 

Malsch, Marty Egan, Fitzpatrick, Malsch, & 

Lawrence PLLC 

080-04 ML15294A368 

McCullum, Rodney 

Nuclear Energy Institute, 

Senior Director, Used Fuel & 

Decommissioning 

143 ML15328A151 

McCullum, Rodney 

Nuclear Energy Institute, Senior 

Director, 

Used Fuel & Decommissioning 

147-17 ML15268A399 

McCullum, Rodney 

Nuclear Energy Institute, Senior 

Director, 

Used Fuel & Decommissioning 

149-11 ML15274A168 

McFarland, Teresa Private Citizen 094 ML15292A136 

McMillan, Kristin; and 

Anderson, Hugh 

Las Vegas Metro Chamber of 

Commerce, 

President and CEO 

Las Vegas Metro Chamber of 

Commerce, 

Government Affairs Committee 

Chairman 

127 ML15344A098 

Merritt, Dave Private Citizen 149-03 ML15274A168 

Michetti, Susan Private Citizen 108 ML15336A978 

Michetti, Susan Private Citizen 111 ML15292A095 

Miller, Conrad Private Citizen 091 ML15344A091 

Moradkhan, Paul 

Las Vegas Metro Chamber of 

Commerce, 

Vice President of Government Affairs

147-27 ML15268A399 

Mori, Gina Private Citizen 090 ML15344A102 

Morton, Jenna Private Citizen 147-19 ML15268A399 

Moss, Ben Private Citizen 093 ML15342A008 

Nakadegawa, Judy Private Citizen 089 ML15343A386 

Nelson, Dennis 

Support and Education for Radiation 

Victims, 

Director 

146-15 ML15253A669 

Nelson, Scott Private Citizen 092 ML15343A391 

Nester, Dennis Private Citizen 087 ML15287A394 

Nichols, John Private Citizen 088 ML15344A094 
B–119 

Table B-3. Individuals Who Submitted Written or Oral Comments 

Commenter Affiliation and Title

(if provided) 

Document 

Identification 

Number 

ADAMS 

Accession 

Number 

Noel, Amy Private Citizen 149-09 ML15274A168 

O'Brien, Michael Private Citizen 053 ML15275A160 

Olson, Mary Nuclear Information and Resource 

Service 146-02 ML15253A669 

Olson, Mary Nuclear Information and Resource 

Service 

080-10 ML15294A368 

Olson, Mary; and Nuclear Information and Resource 

Service 

134 ML15344A171 

Donnelly, Patrick Amargosa Conservancy, 

Executive Director 

Parks, David Nevada State Senate, Senator District 

7 147-07 ML15268A399 

Paz, Jacob Private Citizen 116 ML15337A076 

Paz, Jacob Private Citizen 147-12 ML15268A399 

Phillips, Kevin 

Lincoln County (Nevada) Board of 

Commissioners, 

Chairman 

123 ML15336A979 

Pierman, Bette Michigan Safe Energy Future 048 ML15344A275 

Pierman, Bette Michigan Safe Energy Future 095-05 ML15321A414 

Pineda, Cecile No Nuke Committee San Francisco 080-01 ML15294A368 

Pitesa, Bill Duke Energy, 

Chief Nuclear Officer 145 ML15323A409 

Port, Patricia U.S. Department of the Interior, 

Regional Environmental Officer 140 ML15299A094 

Poulson, Judi Fairmont, Minnesota Peace Group, 

Chair 050 ML15343A025 

Regan, Robert Private Citizen 149-18 ML15274A168 

Regez, Hendrica Private Citizen 057 ML15336A977 

Reid, Harry U.S. Senate, 

Senator for Nevada 056 ML15313A013 

Reid, Harry* U.S. Senate, 

Senator for Nevada 147-09 ML15268A399 

Rivera, Ethyl Private Citizen 095-07 ML15321A414 

Ruby, Kenneth Private Citizen 059 ML15292A173 

Rude, Kathleen Private Citizen 061 ML15344A093 

Sachs, Gary Private Citizen 146-17 ML15253A669 

Sandoval, Brian State of Nevada, Governor 074 ML15287A393 

Sandoval, Brian* State of Nevada, Governor 147-08 ML15268A399 

Schinhofen, Dan Nye County (Nevada), Commissioner 073 ML15313A009 

Schinhofen, Dan Nye County (Nevada), Commissioner 138 ML15328A152 

Schinhofen, Dan Nye County (Nevada), Commissioner 147-11 ML15268A399 

Schinhofen, Dan Nye County (Nevada), Commissioner 149-05 ML15274A168 

Schlapfer, Edwin Private Citizen 072 ML15344A300 

Schoneberger, David Private Citizen 080-05 ML15294A368 
B–120 

Table B-3. Individuals Who Submitted Written or Oral Comments 

Commenter Affiliation and Title

(if provided) 

Document 

Identification 

Number 

ADAMS 

Accession 

Number 

Science Panel Sustainable Fuel Cycle Task Force 068 ML15336A982 

Seeley, Linda San Luis Obispo Mothers for Peace 075 ML15344A273 

Shapiro, Susan Public Health and Sustainable 

Energy, LLC 133 ML15344A103 

Shaw, Sally Private Citizen 071 ML15343A016 

Sheridan, Paul Private Citizen 054 ML15292A134 

Sims, Millicent Private Citizen 109 ML15313A017 

Spilsbury, Delaine Great Basin Water Network, 

Member of Board of Directors 070 ML15337A077 

Steadmon, Jason Private Citizen 047 ML15343A022 

Steele, Diane Private Citizen 076 ML15343A020 

Stevens, Barbara Private Citizen 146-18 ML15253A669 

Stremmel, Bill Private Citizen 069 ML15313A015 

Stremmel, Bill Private Citizen 080-03 ML15294A368 

Swanson, Lucy Private Citizen 067 ML15344A099 

Thabit, Nick Private Citizen 045 ML15343A023 

Thomas, Ruth Environmentalists, Inc. 146-03 ML15253A669 

Titus, Dina U.S. House of Representatives, 

Congresswoman, Nevada 1st District 147-03 ML15268A399 

Torrisi, Sharon Private Citizen 044 ML15343A024 

Travis, Terence Private Citizen 055 ML15343A027 

Treichel, Judy Nevada Nuclear Waste Task Force, 

Executive Director 147-23 ML15268A399 

Tsongas, Theodora Private Citizen 043 ML15344A303 

Valentine, Virginia Nevada Resort Association 147-18 ML15268A399 

Voeller, Estelle Private Citizen 013 ML15344A270 

Warren, Barbara Citizens' Environmental Coalition 062 ML15344A100 

Watts, Elizabeth Private Citizen 014 ML15344A220 

Weinman, Lissa World Policy Institute 095-11 ML15321A414 

Weisenmiller, Robert 

California Energy Commission, 

Chair and State Liaison Officer to 

NRC 

124 ML15344A101 

Willoghby, Leonard Private Citizen 147-29 ML15268A399 

Wilvert, Rosemary Private Citizen 115 ML15344A208 

Woodward, Holly Private Citizen 026 ML15344A097 

Woodward, Holly Private Citizen 147-21 ML15268A399 

Zabarte, Ian Government of Newe Sogobia, 

Principal Man for Foreign Affairs 024 ML15292A093 

Zabarte, Ian Government of Newe Sogobia, 

Principal Man for Foreign Affairs 131 ML15341A331 

Zabarte, Ian Government of Newe Sogobia, 

Principal Man for Foreign Affairs 147-10 ML15268A399 

*Comments were read at a public meeting on behalf of these commenters 




NUREG-2184

Final

Supplement to the U.S. Department of Energy’s Environmental Impact 

Statement for a Geologic Repository for the Disposal of Spent Nuclear Fuel and 

High-Level Radioactive Waste at Yucca Mountain, Nye County, Nevada