April 2006 5-1 NUREG-1817

5.0 Operation Impacts at the Proposed Site

This chapter examines the environmental issues associated with operation of one or more |

additional nuclear units at the proposed Grand Gulf early site permit (ESP) site for an initial

40-year period as described in the application for an ESP submitted by System Energy

Resources, Inc. (SERI). As part of this application, SERI submitted an environmental report 

(SERI 2005a) that provides the plant parameter envelope (PPE) (see Appendix I) as the basis |

for the environmental review. 

Sections 5.1 through 5.10 of this chapter discuss the potential impacts on land use, air quality,

water, ecosystems, socioeconomics, historic and cultural resources, and environmental justice,

as well as nonradiological and radiological health effects and impacts of postulated accidents. 

In accordance with Title 10 of the Code of Federal Regulations (CFR) Part 51, the impacts have |

been analyzed, and, where possible, a significance level of potential impact – SMALL, |

MODERATE, or LARGE – has been assigned to each analysis. Measures and controls to limit |

adverse impacts of station operation during the initial 40 years are presented in Section 5.11. 

The staff’s determination of significance levels is based on the assumption that the mitigative

measures identified in the environmental report and in Section 5.11 of this environmental |

impact statement (EIS), or activities planned by various State and county governments as

discussed throughout this chapter, such as infrastructure upgrades, are implemented. For |

issues that are considered to be resolved, the staff will verify the continued applicability of all |

assumptions used in its environmental analyses, should an applicant for a CP or COL reference |

the Grand Gulf ESP. These assumptions are listed in Appendix J.1. A summary of the |

operational impacts is presented in Section 5.12. The references cited in this chapter are listed

in Section 5.13.

5.1 Land-Use Impacts

The land-use areas considered include those (such as the site, vicinity, area along transmission

lines, and offsite areas) with the potential to be affected by operational activities. Operations of

the ESP facility are not anticipated to require temporary or permanent changes of any current

or planned land use. 

5.1.1 Site and Vicinity

Operation of the proposed unit or units at the Grand Gulf ESP site would result in social and |

economic impacts that may translate into impacts on land use in the vicinity. These impacts are

discussed in Section 5.5.2. A conservative estimate of the expected increase in population

related to new personnel being employed at the ESP site would be 2320 persons. This |

assumes that all facility-related employment associated with the ESP site would relocate to the |
Operation Impacts at the Proposed Site

NUREG-1817 5-2 April 2006

| impact region (within 80 km (50 mi)) of the ESP site. Section 5.5.2 presents potential

| population impacts within individual jurisdictions, assuming relocations occur in proportion to the

current distribution of worker residences.

The staff analyzed recent mortgage finance data for Claiborne County (FFIEC 2001, 2002,

| 2003, 2004, 2005) to evaluate the potential need for new housing in the vicinity. The Federal

Financial Institutions Examination Council (FFIEC) annually collects data on each mortgage

finance transaction in the country from institutions required to report, including banks, mortgage

companies, credit unions, and other finance companies. The detailed transaction data and

borrower characteristics are provided to the census tract level. Table 5-1 provides a summary

| of such transactions reported in Claiborne County over the recent 5-year period. The data

| indicate that the 225 financed home purchases over the five years ending in 2004 have been

evenly distributed across the county’s three census tracts: the northern portion of the county,

the Port Gibson area, and the southern portion of the county. Section 5.5.2 indicates that plant

workers moving to the region would most likely locate in the Vicksburg area where housing and

services are most available. The home purchase data summarized in Table 5-1 suggest that

| Claiborne County conservatively averages just 45 home sales annually, distributed somewhat

evenly across the county.

| Table 5-1. Mortgage Transactions in Claiborne County, Mississippi, 2000 to 2004

| 2000 2001 2002 2003 2004

| Home Purchase Mortgages 71 54 31 40 29

| Average Loan Amount ($K) 43.2 52.3 47.5 55.3 62.4

| Median Loan Amount ($K) 32.0 35.5 47.0 48.5 53.0

| Average Annual Borrower Income ($K) 36.8 43.5 40.3 41.1 47.4

| Median Annual Borrower Income ($K) 36 36 36 32 47

| Source: FFIEC Home Mortgage Disclosure Act data (FFIEC 2001, 2002, 2003, 2004, 2005). These

data include only mortgage transactions financed through Federally regulated institutions. 

Cash purchases are not included. 

Based on this analysis and information presented in Section 5.5.2, the staff finds that relocating

workers would tend to seek housing where it is currently most available and where the choice of

homes is greatest, such as Vicksburg, Natchez, or Clinton. Relocation in proportion to the

current distribution of worker residences is unlikely, given current housing availability in

Claiborne County. It is not possible to know what real estate or land development might occur

in Claiborne County as a result of siting and operating the ESP facility. Therefore, the staff

concludes that land-use impacts from development of new housing would occur, but such
Operation Impacts at the Proposed Site

April 2006 5-3 NUREG-1817

impacts would be widely disbursed and would not be concentrated in any one community. Such

impacts might include land-cover alteration on private lands, new property access roads, or

conversion from private agricultural to residential use.

Adding the Grand Gulf ESP facility to the Grand Gulf Nuclear Station (GGNS) site would |

introduce staggered refueling and maintenance outages. It is likely that outages would be |

scheduled for one facility at a time, increasing the frequency of the need for temporary outage |

workers and increasing the number by 100 to 200 workers (SERI 2005a). This increase in |

frequency would lead to increased impacts at local campgrounds and other local temporary |

housing facilities in the vicinity on a sustained basis. However, these impacts would not be |

expected to noticeably alter current land uses in the vicinity. |

Another potential impact on land use includes the effects of salt drift on crops, timber, and other |

vegetation from operation of wet cooling towers (either natural or mechanical draft) that have

been proposed for the Grand Gulf ESP facility. Forests both on the Grand Gulf site and offsite

to the northwest of the ESP facility would be in the path of vapor plumes carried on |

southeasterly prevailing winds (SERI 2005a) and could thus be affected by salt drift. However, |

agricultural land occurs only offsite and largely to the southeast and east of the Grand Gulf

ESP site, and thus would be less likely to be affected by salt drift, based on the direction of

prevailing winds.

The staff assumed that new cooling towers would produce salt concentrations similar to cooling |

towers at existing nuclear power plants. New cooling towers would be located near the existing

natural draft cooling tower at the Grand Gulf site and would be subject to the same

meteorological conditions and, therefore, produce a similar plume footprint, potentially tripling |

the current salt deposition. A salt drift deposition study was conduced for GGNS Unit 1 from |

1983 to 1988. The salt drift deposition rate was not significantly different between onsite and |

offsite locations. Consequently, a supplemental study was not undertaken to determine the |

biological effects of the salt at the Grand Gulf site (Entergy 1992). The impact of salt drift on |

crops, ornamental vegetation, and native plants was evaluated for existing nuclear power plants

in the Generic Environmental Impact Statement for License Renewal of Nuclear Plants (GEIS) |

(NRC 1996) and was found to be of minor significance. This determination also included

existing nuclear power plants with more than one cooling tower. Consequently, damage to

timber or crops from the operation of cooling towers for the Grand Gulf ESP facility would

be negligible. |

Impacts on land use that would occur include minor land cover alterations because of the |

geographically disbursed construction of new housing for ESP facility workers. Therefore, the

staff concludes that land-use impacts in the vicinity of the ESP facility due to operations would

be SMALL, and additional mitigation would not be warranted.
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NUREG-1817 5-4 April 2006

5.1.2 Transmission Line Rights-of-Way and Offsite Areas

Section 4.1.2 indicates that although the current transmission system serving the GGNS site is

likely to be inadequate under the bounding assumptions of the PPE, the full extent of changes

| to the transmission system cannot be known until an applicant for a CP or COL initiates the

| Federal Energy Regulatory Commission process for connecting new large generation to the

grid. This process is discussed more specifically in Section 3.3. Whether that process results

in findings that the existing rights-of-way can be upgraded, or that new rights-of-way must be

| acquired, maintenance of the transmission lines is expected to be accomplished using standard

| industry practices and following applicable laws and regulations. Impacts on land use would

occur as a result of normal maintenance activities, such as right-of-way vegetation clearing,

| transmission line maintenance, and other normal access needs. Impacts on land use during

the construction phase are discussed in Section 4.1.2, and the subsequent impacts of

| transmission line and right-of-way maintenance would be minimal. These may include access

easements, building restrictions, temporary closures, and other activities as part of routine

maintenance.

| Based on information provided by SERI (2005a) and the U.S. Nuclear Regulatory Commission

| (NRC) staff’s independent review, the staff concludes that land-use impacts in the transmission

| line rights-of-way and offsite areas from ESP facility operations would be SMALL, and

| additional mitigation would not be warranted.

5.2 Meteorological and Air Quality Impacts

Sections 2.3.1 and 2.3.2 describe the meteorological characteristics and air quality of the Grand

Gulf ESP site. The primary impacts of operation of the Grand Gulf ESP facility on local

meteorology and air quality would be from releases to the environment of heat and moisture

| from the primary cooling system (cooling towers), effluent from operation of auxiliary equipment

(generators and boilers), and emissions from workers’ vehicles. This section provides

| information on these factors and discusses the potential impacts of transmission line rights-of-

| way on air quality.

5.2.1 Cooling System

The proposed cooling system for the new nuclear unit or units at the Grand Gulf ESP site is wet

cooling towers. Both natural draft and mechanical draft cooling towers are being considered.

The most apparent impacts of wet cooling towers are the land use and aesthetic impacts

associated with visible plumes. The air-quality impacts of wet cooling towers are associated

with the drift from the cooling towers and possible interactions between the moist plumes and

| other pollutants. Wet cooling towers at existing nuclear power plants generally have drift

eliminators to reduce drift.
Operation Impacts at the Proposed Site

April 2006 5-5 NUREG-1817

Drift is composed of small water droplets that are carried out of the cooling tower. These

droplets evaporate, leaving particles that contain residual salts and chemicals from the cooling

water. Drift from mechanical draft cooling towers is deposited near the cooling tower, and drift

from natural draft towers is deposited farther downwind. Based on a review of the

measurements of deposition of drift from nuclear power plants, the GEIS (NRC 1996) states the |

“...measurements indicate that, beyond about 1.5 km (1 mi) from nuclear plant cooling towers,

salt deposition is not significantly above natural background levels.” |

Based on the above considerations and the assumption that cooling towers associated with the

new nuclear unit or units would be similar to cooling towers at existing nuclear plant sites,

including the GGNS, the staff concludes that the impacts of the cooling towers on air quality

would be SMALL and additional mitigation would not be warranted. |

5.2.2 Routine Releases Other than Cooling System

Operation of auxiliary equipment, such as generators and boilers associated with a postulated

facility at the Grand Gulf ESP site, would be intermittent. SERI provided bounding values for

particulate sulfur and nitrogen oxides, carbon monoxide, and hydrocarbon emissions from

auxiliary boilers, standby diesel generators, and standby power system gas turbines in the PPE. 

Auxiliary boilers are assumed to operate 30 days per year, and standby diesel generators and

standby power system gas turbines are assumed to operate 4 hours per month. SERI (2005a) |

states that gaseous releases associated with the postulated units would comply with Federal,

State, and local emission standards. 

No major air pollution sources exist near the Grand Gulf ESP site. Diesel generators and

boilers at the GGNS operate for limited periods. Generators and boilers associated with the

new nuclear unit or units would also be operated for limited periods. Emissions from the

generators and boilers would be minor compared to emissions from boilers and generators that

run continuously. Interactions between pollutants emitted from these sources and the plumes

from the new nuclear unit cooling towers would be intermittent and would not have a significant

impact on air quality.

Because these systems are used on an infrequent basis and no significant industrial source

exists within 16 km (10 mi) of the proposed site, the staff concludes the impacts of these

releases would be SMALL.

5.2.3 Transmission Line Impacts

The impacts of existing transmission lines on air quality are reviewed in the GEIS (NRC 1996). 

Small amounts of ozone and smaller amounts of oxides of nitrogen are produced by

transmission lines. The small amounts of these gases were found to be insignificant for
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NUREG-1817 5-6 April 2006

745-kV lines (the largest lines in operation) and for a prototype 1200-kV line. In addition, the

| staff determined that potential mitigation measures would be very costly and would not be

warranted. The largest existing line in the transmission and distribution system serving the

proposed Grand Gulf ESP site is a 500-kV line, well within the range of lines considered in

NUREG-1437.

Based on the information provided by SERI, the staff’s independent review, and the analyses

| discussed above, the staff concludes the potential transmission line impacts of operation of the

| Grand Gulf ESP facility would be SMALL, and additional mitigation would not be warranted.

5.3 Water-Related Impacts

Water-use and water-quality impacts involved in the operation of a nuclear power plant are

similar to the impacts that would be associated with any large thermoelectric power generation

| facility. Accordingly, SERI would need to obtain similar water-related permits and certifications

| as any other large industrial facility. These would likely include

• Clean Water Act Section 401 certification. This certification would be issued by the

| Mississippi Department of Environmental Quality (MDEQ) and would ensure that the project

does not conflict with State water quality management programs.

| • Clean Water Act Sections 402(a) and 402(p) National Pollutant Discharge Elimination

| System (NPDES) discharge permit. These permits would be issued by MDEQ and would

| regulate point source and storm water discharges. The U.S. Environmental Protection

Agency (EPA) has delegated the responsibility for administering the NPDES program in

Mississippi to MDEQ.

• Clean Water Act Section 316(a). This section regulates heated and chlorinated cooling

water discharges to protect the health of the aquatic habitat.

• Clean Water Act Section 316(b). This section regulates cooling water intake structures to

minimize environmental impacts associated with location, design, construction, and capacity

of those structures. 

• Section 10 of the Rivers and Harbors Act of 1899. This section prohibits the obstruction or

alteration of navigable waters of the United States without a permit. Appropriate U.S. Army

| Corps of Engineers (ACE) permits would need to be obtained for maintenance of the

proposed intake and discharge structures on the shore of the Mississippi River.

• Section 1424(e) of the Safe Drinking Water Act of 1974. This section prohibits any

commitment for Federal financial assistance (through a grant, contract, loan guarantee, or
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April 2006 5-7 NUREG-1817

otherwise) for any project which the EPA Administrator determines may contaminate an

aquifer designated by the Administrator to be a sole-source aquifer. EPA has identified the

Southern Hills Aquifer, which includes the Catahoula formation beneath the Grand Gulf ESP

site, to be a sole-source aquifer (EPA 1998).

Managing water resources requires understanding and balancing the tradeoffs between

various, often conflicting objectives. At the Grand Gulf ESP site, these include navigation,

recreation, visual aesthetics, fishery, and a variety of beneficial consumptive domestic and

industrial uses of water. The responsibility for regulating water use and water quality is

delegated to ACE and MDEQ through Federal laws and laws of the state of Mississippi. This |

section discusses the estimated impacts on water use and water quality resulting from

operation of a facility at the Grand Gulf ESP site bounded by the PPE.

5.3.1 Hydrological Alterations

The staff did not identify any significant changes to the local flow patterns or intensities that |

would occur at the site due to operation. The site drainage system would generally drain |

surface water runoff and storm flow in approximately the same levels to Stream A and |

Stream B. Any increase in runoff intensity resulting from the increase in the impervious surface |

area would be mitigated using standard engineering storm water management practices |

pursuant to the site’s NPDES storm water management program. Given the small amount of |

water withdrawn for a new nuclear facility relative to the large flow of the Mississippi River, the |

intake and discharge would have minimal impact on the river’s flow pattern adjacent to the |

shoreline. |

Any dewatering systems active during operation would only impact the shallow aquifers. |

However, based on the character of the shallow groundwater system, the staff concluded that |

any impacts on the groundwater flow pattern would be localized and any change would unlikely |

extend beyond the site boundary. |

Based on the above, the NRC staff concludes that the impact of hydrological alterations from |

operation would be SMALL, and additional mitigation would not be warranted. |

5.3.2 Water-Use Impacts

Certain details concerning operation of a new nuclear facility at the Grand Gulf ESP site are not |

known at the ESP stage. Consequently, the staff’s analysis is not to the depth warranted for |

actual operation. It is, however, sufficient for the purpose of comparing the proposed action to |

the alternatives. |
Operation Impacts at the Proposed Site

NUREG-1817 5-8 April 2006

| A new nuclear facility would use surface water from the Mississippi River for cooling purposes

and groundwater from the Catahoula formation for other facility water needs. By far, the largest

single use of water for the proposed Grand Gulf ESP facility would be makeup for the normal

heat sink. SERI stated that operation of the makeup water system for a new facility would have

| a negligible impact on the use and water supply of the Mississippi River (SERI 2005a). Normal

makeup flow rate to a new nuclear facility would be approximately 3175 L/s (50,320 gpm), and

the maximum expected makeup flow would be 5400 L/s (85,000 gpm). About 25 percent of

this water would be returned to the Mississippi River as blowdown. The staff concludes that a

new facility would withdraw only a small amount of water relative to the total river flow (about

0.2 percent) at even the lowest minimum river discharge conditions recorded for the area. Also,

because of the proposed location and the small area of the river that would be affected by the

proposed new facility, the staff concludes that the intake structure would not affect recreational

or commercial fishing operations or otherwise restrict navigation on the Mississippi River. 

Because the withdrawal would be small relative to river flow (conservatively considering

withdrawals for both the proposed ESP unit(s) and the existing GGNS Unit 1), the staff

concludes that impacts would be small.

SERI stated that no water from Stream A or Stream B would be used by the proposed new

| nuclear facility (SERI 2005a). However, the alteration of the existing landscape would likely

increase the impervious surfaces at the site, thereby increasing storm water flow. While this

could possibly alter the timing and magnitude of runoff without significantly altering the overall

water budget, the staff concludes that, by employing standard best management practices for

storm water management, the impact of the ESP facility on water uses associated with

Stream A and Stream B would be insignificant.

No new consumptive wells in the Holocene alluvial aquifer are proposed for operation of the

new facility; therefore, the staff concludes no impacts would be anticipated on the alluvial

aquifer. 

| SERI (2005a) stated that the use of the additional wells installed in the Catahoula formation for

water needs other than for cooling makeup water would not significantly affect the groundwater

water surface elevation in the vicinity. However, the staff concludes that the characterization of

the Catahoula aquifer was inadequate to support such a conclusion, particularly given the

significance of the aquifer to local domestic water supplies and its designation by EPA as a

sole-source aquifer (EPA 1998). Because of the limited number of borings, hydraulic

conductivity measurements, and long-term pump tests in this portion of the aquifer that are

currently available, the staff was unable to assess reliably the impact of a significant increase in

| the groundwater withdrawal at the Grand Gulf ESP site. Given the information provided in the

| applicant’s environmental report and the staff’s independent review, impact on the Catahoula

| formation could be SMALL if the proposed withdrawal had little effect on the Catahoula

| formation or MODERATE if the proposed withdrawal were to adversely affect current water

| withdrawals elsewhere in the aquifer. An applicant for a CP or COL referencing an ESP for the
Operation Impacts at the Proposed Site

April 2006 5-9 NUREG-1817

Grand Gulf ESP site would need to provide additional information on the ability of the Catahoula |

aquifer to sustain withdrawals in order for the staff to make a significance determination with |

respect to this resource. Use of wells that withdraw from the Catahoula formation would be in |

accordance with applicable standards published in the MDEQ groundwater use and protection |

regulations (MDEQ1994), and necessary permits would be obtained from the MDEQ. MDEQ |

regulations allow for permit denial or reduction of withdrawal rate if such a withdrawal is |

expected to interfere with existing permitted uses of if it conflicts with the public interest. |

Based on its review, the staff concludes that the issue of water-use impacts resulting from |

operational activities on groundwater at the Grand Gulf ESP site is unresolved. Additional |

aquifer characterization would need to be provided by an applicant for a CP or COL referencing |

an ESP for the Grand Gulf ESP site. |

5.3.3 Water-Quality Impacts

Certain details concerning operation of a new nuclear facility at the Grand Gulf ESP site are not |

known at the ESP stage. Consequently, the staff’s analysis is not to the depth warranted for |

actual operation. It is, however, sufficient for the purpose of comparing the proposed action to |

the alternatives. |

In Section 5.3.2 of its environmental report (SERI 2005a), SERI described the impact of effluent |

discharges from both the existing GGNS Unit 1 and the proposed ESP facility. While the

specific design of the outfall, including the diffuser, has not yet been specified, parameters from

the PPE were used to bound the impact of the outfall on the river environment. Environmental

parameters, such as river discharge and receiving water temperature, were also varied in this

analysis, using the historical record.

5.3.3.1 Mississippi River

SERI’s environmental report (2005a) assumed the discharge outfall would enter the Mississippi |

River several hundred feet downstream of the intake screens and on the east bank (the same |

side as the Grand Gulf ESP site) of the river. The proposed discharge would enter

perpendicular to the river via a shoreline-located discharge canal that would be rectangular in

cross-section. The canal at the terminus was assumed to be 10 m (33 ft) wide by 0.5 m (1.6 ft)

deep. Regardless of river environment, local river depth at the shoreline- located discharge exit

would be 0.5 m (1.6 ft) deep, and the bank would slope 19.3 degrees. Based upon PPE values

for the Grand Gulf ESP facility and the Updated Final Safety Analysis Report (UFSAR) (MP&L

1994) for GGNS Unit 1, the bounding discharge flow rate was assumed to be 3.34 m3/s

(52,900 gpm) at a temperature of 37.7°C (100°F).
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NUREG-1817 5-10 April 2006

For purposes of determining bounding conditions, the variable flow conditions of the river were

| examined. Mississippi River flows examined by SERI (SERI 2005a) were assumed to be either

15,860 m3/s (560,000 cfs) for average river flow or 3653 m3/s (129,000 cfs) for low river flow. 

The river was assumed to be rectangular in cross-section, with a constant width of 884 m

(2900 ft) and a depth of either 9.44 m (31.0 ft) for the average river flow or 2.44 m (8.00 ft) for

low river flow. These combinations of discharges and cross-sectional areas results in a mean

| ambient river velocity of 1.9 m/s (6.2 ft/s) for average flow and 1.69 m/s (5.54 ft/s) for low flow. 

| Ambient winter river water temperatures examined were 1°C (34°F) and 4°C (39°F) and

| ambient summer river water temperatures were 27.8°C (82.0°F) and 30.6°C (87.1°F).

SERI estimated the length and width of the discharge plume using the Cornell Mixing Zone

Expert System (CORMIX) version 3.2 (Jirka et al. 1996). Simulation parameters and summary

| of results are shown in the environmental report (SERI 2005a). The plume width and length

were defined in the analysis as the location of the 2.8°C (5°F) isotherm. CORMIX version 3.2

results indicate the maximum width and length of the plume to have occurred with the higher

discharge and colder river case. Under these conditions, the worst case (i.e., largest) surface

extent of the plume was reported to be 187 m (614 ft) long and 16.3 m (53.5 ft) wide.

| The NRC staff performed an independent analysis of the outfall plume using CORMIX

| version 4.3 (Jirka et al. 2004). This is the most recent version of the CORMIX model available

and includes several revisions to the buoyant plume algorithms that are germane to the SERI

application. The staff’s evaluation assumed that the discharge plume would enter

perpendicular to the river, several hundred feet downstream of the intake screens. The canal

| terminus was assumed to be 10 m (33 ft) wide by 0.5 m (1.6 ft), and the local river depth at the

| outfall location was assumed to be 0.5 m (1.6 ft). Based on the UFSAR (MP&L 1994), the

slope of the protected river bank was assumed to be 14 degrees (approximately 4 ft horizontal

| for every vertical foot). Based upon PPE bounding values (SERI 2005a) and the UFSAR

(MP&L 1994), the outfall discharge was assumed to be 3.34 m3/s (52,900 gpm) at a

temperature of 37.7°C (100°F).

| The staff evaluated two assumed river discharges during their analysis. These discharges were

based on monthly average Mississippi River streamflow data collected between 1931 and 1998

near Vicksburg by the U.S. Geological Survey (USGS 2004). From this dataset, the mean flow 

was approximately 17,040 m3/s (601,800 cfs) and the low flow was 3115 m3/s (110,000 cfs). 

Water temperature data maxima and minima were examined between 1962 and 1979 to

determine bounding values. Based upon the UFSAR (MP&L 1994), the average winter water 

temperature is 5°C (41°F) with a minimum of approximately 1°C (34°F). The average summer

river temperature is 27.8°C (82.0°F), with a maximum of 30.6°C (87.1°F).

The cross-sectional areas of the river at both the mean and the low flow were determined

| using ACE (2001), SERI’s environmental report (SERI 2005a), and the UFSAR (MP&L 1994). 

For the mean flow scenarios, the river width was 1000 m (3281 ft) and the average water depth
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April 2006 5-11 NUREG-1817

was 13 m (43 ft), resulting in an ambient river water velocity of 1.31 m/s (4.30 ft/s). For the low- |

flow scenarios, the river width was 730 m (2400 ft) and the average water depth of 5.7 m (19 ft),

resulting in an ambient river water velocity of 0.75 m/s (2.5 ft/s). Ambient water velocities |

match typical observed values at similar river discharges.

Plume dimensions computed using CORMIX version 4.3 are presented in Table 5-2 for the

eight different scenarios. The plume is larger in winter because of the much larger difference

between ambient and outfall temperatures. The winter low-flow scenario with the minimum

ambient river temperature produced the largest plume, with a length of 387 m (1270 ft) and a

width of 58 m (190 ft). The winter low-flow scenario results in a mixing zone of 2.2 ha (5.5 ac). 

Table 5-2. Dimensions of 2.8°C (5.0°F) Isotherm Plume in the Mississippi River Based on

the Staff’s CORMIX Simulations

Low River Flow

3115 m3/s

Average River Flow

17,040 m3/s

Case Studied

Ambient River

Temperature(a)

Isotherm

Above

Ambient

Considered(a)

Mixing Zone

Length(b)

Mixing

Zone

Width(b)

Mixing

Zone

Length(b)

Mixing

Zone

Width(b)

Summer high

temperature

30.6 (87) 2.8 (5.0) 72 (236) 36 (118) 8 (26) 10 (33)

Summer average 

temperature

27.8 (82) 2.8 (5.0) 75 (246) 34 (112) 8 (26) 9 (30)

W inter mean 

temperature

 5 (41) 2.8 (5.0) 352 (1150) 53 (174) 254 (833) 21 (69)

W inter low

temperature

 1 (34) 2.8 (5.0) 387 (1270) 58 (190) 265 (869) 26 (85)

(a) °C (°F).

(b) meters (feet).

In addition to these scenarios, several submerged single-port diffuser outfalls were tested to

determine if the size of the plume could be increased beyond those shown in the table above. 

As expected, by using a port diffuser located beneath the water surface, the buoyant jet

entrained ambient water as it rose to the surface. It was therefore concluded that the shoreline

diffuser discussed above is indeed the bounding case.

The maximum predicted size of the 2.8°C (5°F) above-ambient isotherm predicted by

CORMIX version 4.3 is an approximately 400-m by 60-m (1300-ft by 200-ft) wedge-shaped

region downstream of the outfall diffuser. By comparison, the Mississippi River is
Operation Impacts at the Proposed Site

NUREG-1817 5-12 April 2006

approximately 1000 m (3281 ft) wide at this location. An approximate sketch of this plume in

| relation to the site is shown in Figure 5-1. The NRC staff concludes, therefore, that the impact

of the thermal plume on the Mississippi River would be small and localized. The thermal

discharge to the Mississippi River would be regulated by the MDEQ.

The staff extended its thermal impact assessment using the CORMIX model to consider the

potential impacts of chemical pollutants in the discharge to the Mississippi River. The results

presented in Table 5-2 can be used to derive mixing zone dilution factors for the cases

considered in the thermal analysis. The dilution factor is the fractional concentration of a unit

concentration in the discharge at the edge of the mixing zone. For instance, if the dilution factor

were 10 percent and the discharge concentration were 20 ppm, then the concentration at the

edge of the mixing zone would be 2 ppm. Table 5-3 presents dilution factors and the mixing

zone (plume) dimensions for the four scenarios considered in the staff’s thermal analysis.

For an 8-percent dilution factor, based on the low-flow condition, the mixing zone for the

combined discharge from GGNS Unit 1 and the proposed ESP facility would be approximately

400 m long by 60 m wide (1300 ft by 200 ft). Again, this 60-m (200-ft) width is in comparison to

the 1000-m (3281-ft) width of the Mississippi River at this location. The chemical discharge to

| the Mississippi River would be regulated by the MDEQ. The blowdown flow rate is expected to

| be more than 100 times greater than these other sources of non-radioactive liquid discharges. 

| Any effluents from these other sources would be diluted by the blowdown effluent before

| entering the Mississippi River. However, SERI did not provide information in the PPE or

| environmental report defining the bounds of concentrations of chemical effluents to be

| discharged to the Mississippi River for sources other than the cooling water blowdown. 

| Consequently, this issue is not considered to be resolved. Accordingly, impacts on Mississippi

| River water quality from chemical effluents (other than in blowdown) cannot now be determined.

| An applicant for a CP or COL referencing an ESP for the Grand Gulf ESP site would need to

| provide information on the concentrations of chemical effluents to the NRC. 

5.3.3.2 Streams A and B

SERI stated that discharges to Streams A and B from the Grand Gulf ESP facility would include

| sanitary waste water, storm water, and sump drains. SERI did not provide information in the

| environmental report defining the bounds of concentrations of chemical effluents to be

| discharged to Streams A and B (SERI 2005a). Consequently, this issue is not considered to be

| resolved. An applicant for a CP or COL referencing an ESP for the Grand Gulf ESP site would

| need to provide information on the concentrations of chemicals in effluents to the NRC. The

| allowable concentrations and volumes of such effluents to Streams A and B would be regulated

| by the MDEQ.
April 2006 5-13 NUREG-1817 Figure 5-1. Bounding Triangle for the Location of the 2.8°C Above-Ambient Isotherm Based upon the Wint

Temperature Difference, Low-Discharge Scenario
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NUREG-1817 5-14 April 2006

Table 5-3. Dilution Factors for Chemical Discharge to the Mississippi River

Based on the Staff’s CORMIX Simulations

Case Studied Dilution Factor

Sum mer high temperature 28%

Sum mer average tem perature 39%

W inter mean temperature 9%

W inter low temperature 8%

5.3.3.3 Groundwater

If very deep groundwater drawdowns were to occur resulting from high groundwater withdrawal

rates during operation of the Grand Gulf ESP facility, it is conceivable that lower quality

groundwater from deeper aquifers would be induced to flow upward into the Catahoula

| formation and possibly degrade the quality of water in the Catahoula formation. Given the

| information provided in the applicant’s environmental report and the staff’s independent review,

| impacts on the Catahoula formation could be SMALL if the proposed withdrawal had little effect

| on the Catahoula formation or LARGE if the proposed withdrawal were to induce degradation of

| the water quality of the sole source aquifer. Further aquifer characterization is needed to

| determine the impacts of additional groundwater withdrawals from the Catahoula formation. 

| Therefore, the issue of impacts to groundwater quality resulting from operational activities at the

| Grand Gulf ESP facility is not resolved. An applicant for a CP or COL that references the ESP

| for the Grand Gulf ESP site would need to provide such additional information for the staff to

| make a significance determination with respect to impacts on groundwater quality.

5.3.3.4 Summary

| SERI did not provide PPE values for non-radioactive liquid discharges other than the blowdown. 

| Although the impact to surface water quality would be SMALL if discharges were within the

| limits of the existing GGNS NPDES permit, the staff cannot rely on assumed compliance with a

| permit in order to reach a conclusion regarding the magnitude of impact. Additional information

| regarding the constituents and associated concentrations for all liquid effluent sources is

| needed in order to determine the impacts of operation on surface water quality to the

| Mississippi River and Streams A and B. Therefore, the issue of impacts to surface water quality

| resulting from operational activities at the Grand Gulf ESP facility is not resolved. An applicant

| for a CP or COL that references the ESP for the Grand Gulf ESP site would need to provide

| such additional information for the staff to make a significance determination with respect to

| impacts on surface water quality.
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April 2006 5-15 NUREG-1817

Water quality impacts to the groundwater resources would be SMALL if the proposed |

groundwater withdrawal had little impact on the Catahoula formation or LARGE if the proposed |

groundwater withdrawal were to induce degradation of the water quality of the sole source |

Catahoula aquifer. The staff concludes that further aquifer characterization is needed to |

determine the impacts of additional groundwater withdrawals from the Catahoula formation. |

Therefore, the issue of impacts to groundwater quality resulting from operational activities at the |

Grand Gulf ESP facility is unresolved. An applicant for a CP or COL that references the ESP |

for the Grand Gulf ESP site would need to provide such additional information for the staff to |

make a significance determination with respect to impacts on groundwater quality. |

5.4 Ecological Impacts

This section describes the potential impacts from operation of the Grand Gulf ESP facility,

including transmission lines and associated right-of-way maintenance, to terrestrial ecosystems, |

aquatic ecosystems, and threatened and endangered species.

5.4.1 Terrestrial Ecosystems

The proposed cooling system for the Grand Gulf ESP facility is closed-cycle that would employ

either natural or mechanical draft cooling towers. The rejected heat would be manifest in the

form of water vapor plumes. Impacts associated with vapor plumes include those resulting |

from salt drift, fogging, and icing. Vapor plumes may affect crops, ornamental vegetation, and

native plants, and water losses could affect shoreline habitat. In addition, bird collisions and

noise-related impacts are possible with wet cooling towers. Each of these topics is discussed in |

the following paragraphs.

Electric transmission systems have the potential to affect terrestrial ecological resources

through right-of-way maintenance, bird collisions with power lines, and electromagnetic fields

(EMFs). The transmission and distribution system existing at the time of startup and operation |

of the proposed Grand Gulf ESP facility would be relied upon to distribute the power generated. 

A study conducted by SERI concluded that the existing system is adequate for an additional

1311 MW(e) generating capacity, assuming that modifications and upgrades are made to |

equipment in the switchyard of GGNS Unit 1. However, the maximum generating capacity is

approximately 3000 MW(e) (SERI 2005a). If 3000-MW(e) generating capacity were installed, |

the existing transmission lines would have to be upgraded or additional transmission lines

would be required.

Should the Grand Gulf ESP facility be constructed, the actual need for and nature of any

transmission system improvements would be determined definitively prior to or during the CP or

COL phase by the transmission and distribution system owner and operator (currently Entergy
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NUREG-1817 5-16 April 2006

| Mississippi, Inc.) under Federal Energy Regulatory Commission Order No. 2003

| (18 CFR Part 35). The magnitude of the environmental impacts associated with any

transmission system improvements would also be established by the transmission and

distribution system owner and operator at that time.

5.4.1.1 Impacts on Crops, Ornamental Vegetation, and Native Plants

Impacts on crops, ornamental vegetation, and native plants may result from cooling tower salt

drift, icing, fogging, or increased humidity. No agricultural land exists on the Grand Gulf site. 

Offsite and in the immediate vicinity of the location of the Grand Gulf ESP facility, there is

agricultural land only to the southeast and east, and winds originate most frequently in the

| southeast (SERI 2005a). Based solely on the direction of prevailing winds, it appears unlikely

that cooling tower impacts on crops and ornamental vegetation would result. However, forests

and forested wetlands both onsite and offsite to the northwest of the Grand Gulf ESP facility

could be in the path of vapor plumes carried on southeasterly prevailing winds and could thus

be affected.

It is assumed that new cooling towers would produce salt concentrations similar to cooling

towers at existing nuclear power plants. New cooling towers would be located near the existing

natural draft cooling tower at the Grand Gulf site and be subject to the same meteorological

conditions and hence produce a similar plume footprint, potentially tripling the current salt

deposition. A salt drift deposition study was conducted for GGNS Unit 1 from 1983 to 1988. 

The salt drift deposition rate was not significantly different between onsite and offsite locations. 

Consequently, a supplemental study was not undertaken to determine the biological effects of

salt drift at the Grand Gulf site (Entergy 1992). The impact of salt drift on crops, ornamental

vegetation, and native plants was evaluated for existing nuclear power plants in the GEIS

| (NRC 1996) and was found to be of minor significance. This determination also included

existing nuclear power plants with more than one cooling tower. Information from the GEIS for

license renewal is useful for this analysis. Therefore, the potential impact on crops, ornamental

vegetation, and native plants from the operation of cooling towers for the Grand Gulf ESP

| facility would be minimal and mitigation would not be warranted.

5.4.1.2 Bird Collisions with Cooling Towers

Although the Grand Gulf ESP site is located adjacent to the Mississippi River and thus along

the Mississippi flyway (Bird Nature 2004), no bird collisions have been reported for the existing

| 159-m (522-ft) GGNS Unit 1 natural draft cooling tower (SERI 2005a). However, there is no

plan in place to monitor and report avian fatalities. The conclusion presented in the GEIS

(NRC 1996) is that bird collisions with natural draft cooling towers are of small significance at all

operating nuclear power plants, including those with multiple cooling towers. Mechanical draft

cooling towers are known to cause only negligible avian mortality and were thus not addressed

in the GEIS (NRC 1996). Consequently, the incremental number of bird collisions, if any,
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April 2006 5-17 NUREG-1817

associated with the operation of one or more wet cooling towers for the proposed Grand Gulf |

ESP facility, regardless of the type of cooling tower (natural or mechanical draft) employed,

would be minimal and mitigation would not be warranted. |

5.4.1.3 Noise

For both natural and mechanical draft cooling towers, the noise levels from cooling tower

operation is anticipated to be 55 decibels (dBA) at 300 m (1000 ft) (SERI 2005a). This noise |

level is well below the 80- to 85-dBA threshold at which birds and small mammals are startled |

or frightened (Golden et al. 1980). Thus, noise from operating natural or mechanical draft

cooling towers would not be likely to disturb wildlife beyond the Grand Gulf site perimeter fence,

which is over 300 m (1000 ft) from the source. Consequently, the potential impact on wildlife |

posed by the incremental noise resulting from the operation of one or more wet cooling towers

for the Grand Gulf ESP facility would be minimal and additional mitigation would not |

be warranted. |

5.4.1.4 Shoreline Habitat

Because of the small quantity of water withdrawn and discharged during operation relative to

the flow in the Mississippi River, adverse impacts on the river shoreline are unlikely. SERI has |

estimated the water use for the Grand Gulf ESP facility and the areal extent of the thermal

plume (SERI 2005a). The staff’s independent assessment is presented in Section 5.3.2. The |

amount of water to be withdrawn from the Mississippi River represents about 0.2 percent of the

total lowest minimum flow. The discharge plume, based on the 2.8°C (5°F) above-background

isotherm, would range from 8 to 400 m (26 to 1300 ft) in length and 9 to 60 m (30 to 200 ft) in

width, depending on season and flow (Section 5.3.2). No additional shoreline habitat would be |

exposed from the water removal, and evaporative loss for the proposed facility would be

undetectable and not likely to affect shoreline plants or wildlife. Consequently, the potential |

effects on terrestrial ecology from the drawdown of the Mississippi River resulting from

operation of one or more wet cooling towers for the Grand Gulf ESP facility would be negligible

and mitigation would not be warranted. |

5.4.1.5 Transmission Line Right-of-Way Management (Cutting and Herbicide Application)

It is currently anticipated that if the maximum generating capacity for the Grand Gulf ESP

facility (approximately 3000 MW(e)) (SERI 2005a) were installed, the existing transmission lines |

would have to be upgraded or additional transmission lines would be required. It is assumed

that any transmission line improvements, such as the addition of new lines and pole support

structures, for example, would be sited within the existing transmission line rights-of-way to the |

greatest extent possible and that no new rights-of-way would be required (Section 4.4.1.2). 
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NUREG-1817 5-18 April 2006

| However, it is possible that the width of the existing rights-of-way would need to be increased

| (Section 4.4.1.2). Existing roads providing access to the current transmission line rights-of-way 

| likely would be sufficient for use in any expanded right-of-way and no new roads would

be required.

| The staff assumes that the same vegetation management practices currently employed by

| Entergy Mississippi, Inc. for the existing GGNS Unit 1 facility transmission line rights-of-way

(such as, bushhogging on an as-needed basis as discussed in Section 2.7.1.1) would be

| applied to any expanded rights-of-way associated with the Grand Gulf ESP facility. Thus, for

| the Grand Gulf ESP facility, vegetation management would simply occur along the same rights-

| of-way, but potentially over twice the area. Transmission line right-of-way maintenance was

evaluated in the GEIS (NRC 1996), and the impact was found to be of small significance at

| operating nuclear power plants with associated transmission line rights-of-way of variable

| widths. Consequently, the incremental effects of transmission line right-of-way maintenance

| posed by increasing the width of the existing rights-of-way for the Grand Gulf ESP facility would

| be minimal. Entergy Mississippi, Inc. would follow best management practices and coordinate

| with Federal and State agencies; thus, no other mitigation would be warranted.

5.4.1.6 Bird Collisions with Transmission Lines

| Transmission line and right-of-way maintenance personnel have not reported dead birds from

collisions with the GGNS Unit 1 plant transmission lines. However, there is no plan in place to

monitor and report avian fatalities under transmission lines. The conclusion presented in the

| GEIS (NRC 1996) is that bird collisions with transmission lines are of small significance at

| operating nuclear power plants, including transmission line rights-of-way with variable numbers

of power lines.

Thus, although additional transmission lines could be required for the Grand Gulf ESP facility

(see Section 4.4.1.2), these would likely present few new opportunities for bird collisions. The

additional number of bird collisions, if any, would not be expected to cause a measurable

reduction in local bird populations. Consequently, the incremental number of bird collisions

posed by possible addition of new transmission lines for the Grand Gulf ESP facility would be

| negligible and mitigation would not be warranted.

5.4.1.7 Impact of Electromagnetic Fields on Flora and Fauna (Plants, Agricultural Crops,

Honeybees, Wildlife, Livestock)

| EMFs are unlike other agents that have an adverse impact (e.g., toxic chemicals and ionizing

| radiation) in that dramatic acute effects cannot be demonstrated and long-term effects, if they

| exist, are subtle (NRC 1996). As discussed in the GEIS (NRC 1996), a careful review of

| biological and physical studies of EMFs did not reveal consistent evidence linking harmful

| effects with field exposures. Thus, the conclusion presented in the GEIS (NRC 1996) was that
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April 2006 5-19 NUREG-1817

the impacts of EMFs on terrestrial flora and fauna were of small significance at operating |

nuclear power plants, including transmission systems with variable numbers of power lines. |

Since 1997, over a dozen studies have been published that looked at cancer in animals that |

were exposed to EMF for all or most of their lives (Moulder 2005). These studies have found |

no evidence that EMFs cause any specific types of cancer in rats or mice (Moulder 2005). |

Therefore, the staff concludes that the incremental EMF impact posed by possible addition of |

new power lines for a new nuclear unit or units at the Grand Gulf ESP site would be minimal |

and mitigation would not be warranted. |

5.4.1.8 Floodplains and Wetlands on Transmission Line Rights-of-Way

As noted earlier, the existing transmission lines would have to be upgraded or additional

transmission lines would be required to support the full PPE. These upgrades likely would be |

sited within the existing rights-of-way to the greatest extent possible. However, these upgrades |

could potentially increase the width of the existing rights-of-way. It is assumed existing roads |

providing access to the current transmission line rights-of-way would be sufficient for use in any |

expanded right-of-way and that no new roads would be required. |

The effects of transmission line right-of-way maintenance on floodplains and wetlands was

evaluated previously in the GEIS (NRC 1996). The impacts were found to be of small

significance at operating nuclear power plants, and these included transmission line rights-of- |

way of variable widths. The incremental effects of transmission line right-of-way maintenance |

on floodplains and wetlands posed by increasing the width of the existing rights-of-way for the |

Grand Gulf ESP facility would be negligible and mitigation beyond use of best management

practices would not be warranted. |

5.4.1.9 State-Listed Species

Animal Species

The endangered wood stork (Mycteria americana) was observed in the summertime on Gin

and/or Hamilton lakes 18 years prior to construction of GGNS Unit 1 (AEC 1973). The wood

stork should be considered a possible non-breeding transient to the Grand Gulf site and vicinity

(SERI 2005a; MNHP 2004a, 2004b). Consequently, the potential impacts from collisions of the |

wood stork with cooling towers and/or any additional transmission lines associated with the |

Grand Gulf ESP facility are considered minimal.

Plant Species

The critically imperiled hairy waterclover (Marsilea vestita) and jug orchid (Platythelys |

querceticola), and the imperiled glade fern (Diplazium pycnocarpon) and American bittersweet

(Celastrus scandens), are known to occur beyond 3.2 km (2 mi) but within 16 km (10 mi) of the
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NUREG-1817 5-20 April 2006

Grand Gulf site (MNHP 2004b). The critically imperiled/imperiled Allegheny monkeyflower

(Mimulus ringens) is known to occur about 17.6 km (11 mi) from the Grand Gulf site

| (SERI 2005a). Although the known locations of these five species occur at some distance from

| the Grand Gulf site, they could yet occur onsite. However, potential impacts on these five

species from the effects of cooling tower operation (salt drift), transmission line operation, and

| right-of-way maintenance, as described above, are considered negligible.

5.4.1.10 Summary of Terrestrial Ecosystem Impacts

The potential impacts of operating wet cooling towers for the Grand Gulf ESP facility on crops, 

| ornamental vegetation, native plants, birds, shoreline habitat, and any related impacts on State-

| listed species are considered negligible. The potential impacts of transmission line right-of-way

| maintenance (cutting and herbicide application) and similar impacts on floodplains and

| wetlands, birds, and biota due to EMFs and any related impacts on State-listed species are

considered negligible.

The staff reviewed the potential terrestrial ecological impacts of a new generation facility at the

| Grand Gulf ESP site including the associated heat-dissipation system, transmission lines, and

| associated right-of-way maintenance. The staff concludes the impacts from operation of the

| Grand Gulf ESP facility would be SMALL, and additional mitigation beyond that mentioned in

| the text would not be warranted.

5.4.2 Aquatic Ecosystems

| The potential impacts on the aquatic ecosystem from operation of a Grand Gulf ESP facility,

including water intake, discharge of heated effluents, physical changes to aquatic systems

| from storm water collection, and transmission line right-of-way maintenance activities

were evaluated.

5.4.2.1 Intake System

For aquatic resources, the primary concerns of water intake are the location of the cooling

water intake structure and the potential for organisms to be impinged on the intake screens or

entrained into the cooling-water system. Impingement occurs when organisms are trapped

against intake screens by the force of the water passing through the cooling-water intake

| structure (66 FR 65256). Impingement can result in starvation and exhaustion, asphyxiation

(water velocity forces may prevent proper gill movement or organisms may be removed from

| the water for prolonged periods of time), and descaling (66 FR 65256). Entrainment occurs

when organisms are drawn through the cooling water intake structure into the cooling system. 

Organisms that become entrained are relatively small benthic, planktonic, and nektonic

(organisms in the water column) forms, including early life stages of fish and shellfish, and
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April 2006 5-21 NUREG-1817

which often serve as prey for larger organisms (66 FR 65256). As entrained organisms pass |

through a plant’s cooling system, they are subject to mechanical, thermal, and toxic stress.

EPA has promulgated regulations that implement Section 316(b) of the Clean Water Act for

new and existing electric power producing facilities (66 FR 65256; 69 FR 41576). The Phase II |

regulations apply to facilities that employ a cooling water intake structure and withdraw

50 million gallons per day or more of water from waters of the United States for cooling

purposes. New nuclear unit or units at the Grand Gulf ESP site would be subject to these |

regulations. The regulations state that if the facility employs a closed-cycle cooling system, |

then the facility is deemed to have met the performance standards to reduce impingement

mortality and entrainment. SERI has not yet finalized a detailed design of the cooling water

system; however, the PPE identifies cooling system designs that employ the use of mechanical |

draft or natural draft cooling systems, both of which are considered a closed-cycle cooling |

system. Therefore, the staff believes that the ESP facilities would meet the performance |

standards specified in the EPA regulations implementing Section 316(b). |

The Grand Gulf ESP facility would, as the existing GGNS Unit 1 does, use cooling towers. 

Losses of fish from impingement and entrainment are significantly less with systems that have

cooling towers because relatively small volumes of makeup water are needed for the

evaporative loss of water in comparison to systems with once-through cooling. GGNS Unit 1

uses radial wells located along the shoreline of the Mississippi River to collect makeup water

through the influx of river and groundwater into the well system. The ESP facility would require

more water than can be generated through the radial well network. An intake structure

designed to collect water from the river itself is proposed to supply the makeup water for the

proposed plant (SERI 2005a). |

The proposed intake structure for the Grand Gulf ESP facility and the designs of the other

portions of the cooling water system have not been finalized. The flow for makeup water from

the Mississippi River is estimated to average 3175 L/s (50,320 gpm), with a maximum peak

flow of 5400 L/s (85,000 gpm). The maximum peak flow would equal about 0.2 percent of the

river flow at the Grand Gulf site under extreme low-flow conditions in the river—3653 m3/s |

(129,000 cfs). The intake structure for the proposed Grand Gulf ESP facility would be of a

different design than the existing radial well system currently used at the GGNS. The intake

structure would be located along the upstream shoreline of the existing barge slip. The intake

would consist of screened suction pipes supplying the makeup water pumps. The intake

screens would be sized so that the average intake velocity through the screen would be less

than or equal to 0.12 m/s (0.5 ft/s). The depth of the intake screens would be such that the |

removal of water would minimize the uptake of aquatic biota and river debris. The plans for the

intake screen are based on a design that is currently being employed at the River Bend Station

intake (SERI 2005a). Located on the Mississippi River at River Mile (RM) 262, the River Bend |

Station is a 2894 MW(t) nuclear power plant that uses closed-cycle cooling dissipating heat |

using mechanical draft cooling towers.
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NUREG-1817 5-22 April 2006

In correspondence with resource agencies associated with the Grand Gulf ESP facility, eight

| aquatic species that could be affected by operation of a new ESP facility (SERI 2005a) were

identified as being of special interest. Four of these species are Federal or State-listed

threatened or endangered species, and are discussed in Section 5.4.3: gulf sturgeon

(Acipenser oxyrinchus desotoi), pallid sturgeon (Scaphirhynchus albus), bayou darter

(Etheostoma rubrum) and crystal darter (Crystallaria asprella). Of the remaining fish species,

chestnut lamprey (Ichthyomyzon castaneus), paddlefish (Polyodon spathula), and blue sucker

(Cycleptus elongatus) were found in the Mississippi River and lakes on the Grand Gulf site in

| GGNS pre-construction surveys (MP&L 1973). The black buffalo (Ictiobus niger) has been

reported from the Mississippi River in the vicinity of the Grand Gulf site (Ross 2001). The black

| buffalo is a species of “special concern” to the state of Mississippi (MNHP 2004a, 2004b). No

biologically important areas (e.g., critical habitats) were identified by the resource agencies as

| being in the immediate vicinity of the Grand Gulf ESP site (SERI 2005a).

As adults, the fish of special interest described above would be able to avoid the proposed

intake structure and not be impinged. Also, the design for the proposed intake structure would

create a low-intake velocity that would not be likely to affect fish. Larval stages of fish and eggs

of fish that are released into the water column travel at the speed of the current of the river. 

These organisms are susceptible to entrainment if they are trapped in the flow of an intake

| structure. A study conducted as part of the GGNS pre-construction surveys in 1972 to 1973

found that the numbers of fish larvae in the Mississippi River at Grand Gulf were low

(MP&L 1973). No fish of special interest were collected. The amount of water that would be

| removed by the intake structure is about 0.2 percent of the overall flow in the river under

| extreme low-flow conditions. 

| Impingement and entrainment can be evaluated by comparing the proposed intake structure for

a new ESP facility to the performance of the similarly designed structure at the once-through

| River Bend Nuclear Station. The intake structure at the River Bend Nuclear Station has an

| intake water velocity of 0.12 m/s (0.5 ft/s) or lower through the screens. The structure is

located within an embayment so as not to block the passage of fish, similar to that proposed for

| the Grand Gulf ESP facility. The final environmental impact statement for the River Bend

Nuclear Station (NRC 1985) concluded that impingement of organisms on the intake screens

was not likely to be a problem because of low-intake velocities. Also, entrained plankton and

other non-swimming species would be limited because the highest density of organisms was

located on the far side of the river, away from the intake structure (NRC 1985). The staff is not

aware of any recent studies of impingement or entrainment conducted at the River Bend

| Nuclear Station that indicate the impact on aquatic organisms has changed. Thus, the use of a

similar intake structure at the Grand Gulf ESP facility would likely also pose a minimal impact

| from impingement and entrainment of aquatic organisms in the Mississippi River (SERI 2005a).
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April 2006 5-23 NUREG-1817

5.4.2.2 Aquatic Thermal Impacts

The effluent discharge from the Grand Gulf ESP facility would be directly into the Mississippi

River, and would be located downstream of the intake embayment to avoid recirculation of

effluents into the river water intake. While the design of the structure has not been finalized, it

was assumed that the shoreline discharge would be located several hundred feet downstream |

of the intake screens. The proposed shoreline discharge would be a concrete structure 10 m |

(33 ft) wide by 0.5 m (1.6 ft) deep. The location is thought to be outside the influence of the |

intake structure and any currents created by the intake embayment and barge slip |

(SERI 2005a). |

SERI and the staff have used the CORMIX model (Section 5.3.2) to estimate the size and |

temperature of the thermal plume from the existing Unit 1 and one or more new ESP nuclear

units. The staff estimated plumes varying from 8 to 387 m (26 to 1270 ft) in length and 9 to |

58 m (30 to 190 ft) in width (Figure 5-1). The size of the plume varied with the summer and |

winter conditions. The model defines the plume as a 2.8°C (5°F) degree difference in

temperature from the ambient water temperature, thus the smaller size of the plume occurred

during the summer.

Impacts on the aquatic organisms in the Mississippi River would be minimized by the proposed |

design of a closed loop cooling system with cooling towers for the Grand Gulf ESP facility. With

this design, the majority of the waste heat would be discharged to the atmosphere and not the

Mississippi River (SERI 2005a). |

The size of the thermal plume from the proposed effluent discharge (defined as 2.8°C (5°F) or |

higher than the ambient temperature of the river) was determined to be small in comparison to |

the width of the Mississippi River at the Grand Gulf ESP site. Fish and other organisms in the

river would move through the plume unencumbered by any structures or physical features that

would retain them in the plume. Furthermore, fish will avoid elevated temperatures that are

potentially harmful, if possible. The increase in temperature expected at the discharge could be

disorienting to organisms moving through the plume, but the temperature is unlikely to be lethal

(NRC 1981a; Fry 1971; Dean 1973; Beitinger et al. 2000).

Cold shock occurs when aquatic organisms that have been acclimated to warm water, such as

fish in a power plant’s discharge canal, are exposed to a sudden temperature decrease. This

sometimes occurs when single-unit power plants shut down suddenly in winter. Cold shock |

mortalities at U.S. nuclear power plants are “relatively rare” and typically involve small numbers |

of fish (NRC 1996). It is less likely to occur at a multiple-unit plant, because the temperature |

decrease from shutting down one unit is moderated by the heated discharge from the unit or |

units that continue to operate. At the Grand Gulf ESP site, the volume of the discharge in |
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NUREG-1817 5-24 April 2006

comparison to the flow of the river is very small. Furthermore, there is no confined area like a

| discharge canal that will attract the fish to the thermal plume and concentrate the organisms

(SERI 2005a).

The thermal plume could affect the movement and distribution of the aquatic biota. The warmer

water could attract some organisms during the colder months. Fish could avoid the plume if the

| temperature were too high. The location and design of the discharge would not impede fish

passage. During normal and minimal flows of the river, the thermal discharge would be along

the river bank. During the flood season, the discharge structure would be below the river level. 

| The amount of water and swift current would quickly mix the effluent with the river water, thus

| minimizing any potential impact (SERI 2005a).

| The location of the discharge along the bank of the Mississippi River, the buoyant nature of the

| plume, the large flow of the river, and the stabilization of the river shoreline by concrete mats

| and riprap would minimize other potential impacts on aquatic organisms from the thermal

| discharge of the proposed ESP facility. Aquatic insects and benthic macrofauna are not in

| great abundance along the shore of the Mississippi River, based on MP&L pre-construction

| surveys in 1972 to 1973, and the conditions are not thought to have changed over time. 

Nuisance organisms are not likely to be encouraged since the discharge is into the river flow

and the substrate is not suitable for colonization by most of these organisms. The plume in the

| river would not be in a confined area for aquatic organisms and the flow of the river would not

| be encumbered by the proposed design such that predation, parasitism and disease, changes

in dissolved gases, or accumulation of contaminants would become an issue (MP&L 1973;

| NRC 1981a; SERI 2005a).

5.4.2.3 Shoreline Erosion and Other Physical Impacts

As mentioned above, the shoreline of the Mississippi River at the GGNS has been stabilized by

concrete mats and riprap. SERI has stated that any disruption of the stabilized banks would be

addressed during operation of the Grand Gulf ESP facility. Periodic dredging of the intake

embayment to remove sediment deposits and littoral debris carried into the embayment would 

| be necessary. Dredging may lead to temporary increase in turbidity in river. These activities

| would require a permit from the ACE and could be timed and conducted to have a minimal

| impact on the existing aquatic resources in the vicinity (MP&L 1973; NRC 1981a; SERI 2005a).

5.4.2.4 Transmission Line Right-of-Way Maintenance Activities

| Maintenance activities along the Baxter-Wilson and Franklin transmission line rights-of-way 

could lead to temporary impacts in the waterways being crossed. Plans for maintenance

| procedures of the widened rights-of-way have not been developed. The impacts on aquatic

resources would vary depending on whether physical or chemical means for controlling

| vegetation in the rights-of-way are used. The maintenance procedures currently being used
Operation Impacts at the Proposed Site

April 2006 5-25 NUREG-1817

(primarily bushhogging performed on an as-needed basis) would likely continue (41 FR 24062). 

If widening the existing rights-of-way is needed, NRC expects that an applicant for a CP or COL |

referencing the Grand Gulf ESP would work with the appropriate Federal and State agencies |

and the transmission line owner, Entergy Mississippi, Inc., to develop and implement the plans |

for rights-of-way maintenance that would have minimal impacts on the aquatic ecosystems. |

5.4.2.5 State-Listed Species

Animal Species

The endangered crystal darter (Crystallaria asprella) is found in Bayou Pierre and its tributaries,

which flow as close as 3 km (1.9 mi) east of the Grand Gulf site (Ross 2001; MNHP 2004b;

Katula 2004). Operation of the Grand Gulf ESP facility would not affect the regions where the |

crystal darter is found. The Franklin transmission line right-of-way crosses Bayou Pierre |

approximately 5.5 km (3.4 mi) to the south of the Grand Gulf site. NRC expects that SERI

would work with the appropriate State agencies and the transmission line owner, Entergy |

Mississippi, Inc., to develop and implement plans for maintenance of the transmission line |

rights-of-way that would have minimal impacts on Bayou Pierre and the crystal darter. |

Plant Species

No State-listed aquatic plant species are known to occur within 16 km (10 mi) of the Grand Gulf

site (MNHP 2004a, 2004b). |

5.4.2.6 Summary of Aquatic Ecosystem Impacts

The final design of the proposed intake and discharge systems for the Grand Gulf ESP facility

would consider potential impacts on aquatic organisms under EPA regulations implementing |

Section 316(b) of the Clean Water Act. The use of cooling towers is a mitigative measure for |

reducing impacts from impingement and entrainment. The characteristics of the thermal

discharge into the river would be reduced through the use of a cooling tower system. The NRC |

staff therefore concludes that the impact from operations would be SMALL, and additional |

mitigation would not be warranted. The NRC staff will verify that any necessary aquatic ecology |

monitoring (see Section 2.7.2.3) would be performed. |

5.4.3 Threatened and Endangered Species

The potential impacts of operation of the ESP facility, including transmission lines and |

associated right-of-way maintenance, on terrestrial and aquatic Federally listed threatened and |

endangered species were evaluated. These species were identified through correspondence |
Operation Impacts at the Proposed Site

NUREG-1817 5-26 April 2006

| with the U.S. Fish and Wildlife Service (FWS) (FWS 2004a, 2004b), review of FWS county

| listings of such species for the state of Mississippi (FWS 2000), and correspondence with the

| National Oceanic and Atmospheric Administration (NOAA) Fisheries (NMFS 2004).

5.4.3.1 Federally Listed Animal Species

Florida Panther - Endangered

Currently no viable populations of the Florida panther (Puma concolor coryi) occur outside of

| Florida (SERI 2005a). Therefore, potential impacts on Florida panthers from facility and

transmission line operation and right-of-way maintenance, as discussed in Section 5.4.1, would

be minimal.

Bald Eagle - Threatened

Bald eagle (Haliaeetus leucocephalus) occurrences have not been reported within 16 km

| (10 mi) of the Grand Gulf site (MNHP 2004b) or within several miles of transmission line rights-

| of-way (Section 4.4.3.1). Therefore, potential impacts on bald eagles from facility and

transmission line operation and right-of-way maintenance, as discussed in Section 5.4.1, would

be minimal.

Interior Least Tern - Endangered

The nearest areas occupied by least terns (Sterna antillarum) upstream and downstream from

| the Grand Gulf site (RM 405) (SERI 2005a) were at Yucatan Dikes (RM 409.8), Togo Island

| Dikes (RM 413.6), and Below Bondurant Towhead Dikes (RM 393.0) (ACE 2004). The areas

| occupied by least terns that are closest to the transmission line rights-of-way are about 3.2 km

| (2 mi) distant (Section 4.4.3.1). Therefore, potential impacts on interior least terns from facility

and transmission line operation and right-of-way maintenance, as discussed in Section 5.4.1,

| would be minimal.

American Alligator - Threatened

The only Federally listed animal species known to inhabit the Grand Gulf site is the threatened

American alligator (Alligator mississippiensis). However, the alligator is listed only because of

its similarity of appearance to the American crocodile (Crocodylus acutus). American alligator

populations are considered disjunct, limited to available habitat but stable (52 FR 21059). 

| Although the alligator is present in wetland habitats onsite, potential impacts on the species

| from the effects of facility and transmission line operation and right-of-way maintenance, as

discussed in Section 5.4.1, would be minimal.
Operation Impacts at the Proposed Site

April 2006 5-27 NUREG-1817

Red-Cockaded Woodpecker - Endangered |

The red-cockaded woodpecker (Picoides borealis) is not known from Claiborne County (Costa |

and Walker 1995) and would thus not be affected by facility operation. The species may occur |

in the vicinity of the Franklin transmission lines, but would not be expected to be adversely |

affected by operation of the lines and may be positively affected by right-of-way maintenance. 

Transmission line right-of-way maintenance practices that favor development of an herbaceous |

understory may foster use of restored old-age long leaf pine (Pinus palustris) stands

(Section 2.7.1.2) by red-cockaded woodpeckers by providing nearby foraging habitat |

(USFS 2005). In 2003, Entergy Corporation entered into a partnership with the National Wild

Turkey Federation to maintain utility rights-of-way on the Homochitto National Forest using low- |

toxicity herbicides for the express purpose of producing a more open, grassy habitat

(USFS 2003). Consequently, right-of-way maintenance would be expected to benefit the red- |

cockaded woodpecker. |

Louisiana Black Bear - Threatened

It is likely that the Louisiana black bear (Ursus americanus luteolus) occurs on and in the |

vicinity of the Grand Gulf site and potentially could be initially affected by noise from cooling |

tower operation. However, if present, the bear likely has become accustomed to noise

produced by the existing GGNS Unit 1 cooling tower. Thus, this potential effect from operation |

of the Grand Gulf ESP facility would be expected to be negligible. The Louisiana black bear |

may occur in the vicinity of transmission line rights-of-way (Section 4.4.3.1) but would not be |

expected to be affected by transmission line operation and right-of-way maintenance. 

Consequently, the potential impacts on the subspecies from facility and transmission line |

operation and right-of-way maintenance, as discussed in Section 5.4.1, would be negligible. |

Gulf Sturgeon - Threatened

The gulf sturgeon (Acipenser oxyrinchus desotoi) has not been collected in the region of the

Grand Gulf site; however, the Mississippi River is considered part of the historical range for the

gulf sturgeon. Therefore, the reach of the river at the Grand Gulf site is likely to be used by the

sturgeon as it migrates up and down the river. No known spawning areas for the gulf sturgeon

exist near the Grand Gulf site, and thus it is unlikely that this area of the river is used by larval

stages of the gulf sturgeon (68 FR 13370; FWS & GSMFC 1995; Ross 2001; NMFS 2004). |

The end of the Baxter-Wilson transmission line right-of-way is no closer then 0.6 km (0.4 mi) to |

the Mississippi River. Thus, the potential impacts from transmission line operation and right-of- |

way maintenance of the transmission line rights-of-way would have no effect on the Mississippi |

River and Gulf Sturgeon. |
Operation Impacts at the Proposed Site

NUREG-1817 5-28 April 2006

The operational activities of the Grand Gulf ESP facility that could influence the juvenile and

adult gulf sturgeon as they migrate through the area would include water removal from the

Mississippi River via a water intake structure and discharge of water downstream. The

proposed intake structure is estimated to have a through-screen velocity of less than 0.2 m/s

| (0.5 ft/s) (SERI 2005a). Juvenile and adult sturgeon could easily escape the planned

through-screen velocity at the plant’s intake structure and would not become impinged on the

screens. The thermal plume created from the discharge of blowdown water from the proposed

plant would not likely influence the migration of the sturgeon. The plume is estimated to have a

| width of 8 to 387 m (26 to 1270 ft), which varies based on the season. The impacts on

sturgeon from such elevated temperatures are not known (Beitinger et al. 2000). However, the

juvenile and adult stages of the sturgeon could easily avoid the thermal plume if the

| temperature were too high. Consequently, impacts on gulf sturgeon from operation of the

Grand Gulf ESP facility would be unlikely.

Bayou Darter - Threatened

The bayou darter (Etheostoma rubrum) is endemic to Bayou Pierre and its tributaries, which

flow as close as 3 km (1.9 mi) east of the Grand Gulf site (40 FR 44149; FWS 1990, 2000;

| 2004a, Ross 2001). The operation of a Grand Gulf ESP facility would not affect the regions

| where the bayou darter is found. The Franklin transmission line right-of-way crosses Bayou

| Pierre. The NRC expects that an applicant for a CP or COL referencing the Grand Gulf ESP

| would work with the appropriate Federal and State agencies and the transmission line owner,

| Entergy Mississippi, Inc., to develop and implement plans for maintenance of the transmission

| line rights-of-way that would have minimal impacts on the Mississippi River and bayou darter.

Fat Pocketbook Mussel - Endangered

The fat pocketbook mussel (Potamilus capax) was historically found throughout the Mississippi

River drainage from Minnesota to Louisiana. In 2003, the mussel was found near Vicksburg in

the Mississippi River, as well as south of the Grand Gulf Site (41 FR 24062; FWS 1989, 2000,

| 2004a, 2004b, 2004c; MNHP 2004c). The adult mussels are found in sand and mud as well as

in stable substrates of fast flowing rivers. Little information is available on the reproduction of

the fat pocketbook mussel; however, they are thought to be similar to other freshwater mussels. 

When the mussels reproduce, the sperm are released into the water column and the sperm are

taken in by the female through siphoning. Fertilized embryos then develop inside the female

mussel into a parasitic stage (glochidia). Upon release from the female, the glochidia attach to

a fish host and, after a period of time, metamorphose into a free-living juvenile. As the mussel

matures, it settles into the sand and mud or onto a stable substrate to grow into an adult. The

fat pocketbook mussel population is thought to be a long-period breeder, spawning in summer,

| retaining glochidia through fall and winter, and releasing them in late spring and early summer.

Gravid females have been found from June through October (CMI 1996).
Operation Impacts at the Proposed Site

April 2006 5-29 NUREG-1817

The end of the Baxter-Wilson transmission line right-of-way is no closer than 0.6 km (0.4 mi) to |

the Mississippi River. Thus, the potential impacts from transmission line operation and right-of- |

way maintenance of the transmission line rights-of-way would have no effect on the Mississippi |

River and fat pocketbook mussel. |

Operation of the Grand Gulf ESP facility would include water removal from the Mississippi River |

via a water intake structure and discharge of water downstream. While the intake screens

would be sized so that the through-screen velocity is less than 0.2 m/s (0.5 ft/s) (SERI 2005a), |

the sperm and free-living juvenile stage of the mussel could be entrained by the water intake

system of the proposed plant. The area influenced by the flow into the intake structure is not

great in comparison to the entire region of the Mississippi River where the mussel might occur. 

Not enough is known about the mussel’s life history to determine if the increased temperature

within the discharge plume of the proposed plant would have any impact; however, it would be

highly unlikely. The area that would be affected by the increased temperature from the

discharge plume is small and the warmer water is buoyant and would not normally impinge on

the river bottom. It is likely that the impact of a thermal discharge from a new nuclear facility |

would be minimal because the region of the shoreline habitat in the Mississippi River that

would change with operation is small compared to the entire shoreline habitat available for

this species.

Pallid Sturgeon - Endangered

Pallid sturgeon (Scaphirhynchus albus) have been collected in the region of the Grand Gulf

ESP site. Adult pallid sturgeon have been caught in regions with moderate to strong currents

and a sand or sand/gravel substrate, similar to the main channel of the Mississippi River as it |

passes by the Grand Gulf site. Little is known about the use of the Mississippi River in the area

of the Grand Gulf ESP site for spawning by the pallid sturgeon. Spawning habitat may exist

within 16 km (10 mi) of the Grand Gulf ESP site. There also is little information about the use

of the reach by larvae or juvenile pallid sturgeon (55 FR 36641; FWS 1993, 2000, 2004a; |

Ross 2001; Hartfield 2003; LDOTD 2003; SERI 2005a). |

The end of the Baxter-Wilson transmission line right-of-way is no closer than 0.6 km (0.4 mi) to |

the Mississippi River. Thus, the potential impacts from transmission line operation and right-of- |

way maintenance of the transmission line rights-of-way would have no effect on the Mississippi |

River and pallid sturgeon. |

The operation of the Grand Gulf ESP facility in the vicinity of the pallid sturgeon’s habitat would

include water removal from the Mississippi River with a water intake structure and discharge of

water downstream. The adult and juvenile sturgeon would likely not be impinged on the
Operation Impacts at the Proposed Site

NUREG-1817 5-30 April 2006

screens of the intake structure because they would easily be able to avoid impingement from

| the anticipated through-screen velocity of water (less than 0.2 m/s (0.5 ft/s)). Larval sturgeon

| (less than 3 cm (1.2 in.) in size) are thought to drift along the bottom of the river (less than

| 0.5 m (1.6 ft) from the bottom) at the velocity of the river (Braaten and Fuller 2005).

Discharge at the downstream structure would create a thermal plume that might affect the

passage of pallid sturgeon on the eastern shore of the Mississippi River. If the sturgeon, at any

| life stage, were to drift through the thermal plume at the average velocity of the river, the

individual would spend from 13 seconds to 15 minutes at temperatures 2.8°C (5°F) or more

above ambient temperature. The estimate of residence time in the plume is based on a river

| velocity of 0.4 to 0.6 m/s (1.3 to 2 ft/s) (SERI 2005a) and a thermal plume estimated by staff to

| have a length of 8 to 387 m (26 to 1270 ft), which varies with the season. The impact on

| sturgeon from such elevated temperatures is not known (Beitinger et al. 2000). However, the

juvenile and adult stages of the sturgeon could easily swim and avoid the thermal plume if the

temperature were too high. There are no known spawning areas in the reach of the Mississippi

River that would be influenced by the thermal plume, and thus the number of larval pallid

| sturgeon in this area of the Mississippi is likely to be low. If the higher temperatures are

detrimental, the larval stages of the pallid sturgeon that are drifting with the river current could

become disoriented, but the temperature increase would not likely be lethal

| (Beitinger et al. 2000). Furthermore, based on the staff’s analysis, the thermal plume is

| buoyant and does not extend more than 1 m (3 ft) below the water surface. Drifting pallid

| sturgeon larvae would, if present, be found near the bottom of the river (Braaten and

| Fuller 2005) and would not be affected by the thermal plume. Therefore, the impacts on pallid

sturgeon from the discharges at the Grand Gulf ESP plant would likely be minimal.

5.4.3.2 Federally Listed Plant Species

| No impacts on Federally listed or proposed threatened or endangered plant species–either

terrestrial or aquatic–are anticipated from operation of the Grand Gulf ESP facility because no

| such plant species are known to occur on or within 16 km (10 mi) of the Grand Gulf site

(MNHP 2004b; FWS 2004a).

5.4.3.3 Summary of Threatened and Endangered Species Impacts

| Because SERI is not planning any preconstruction ground disturbing activities as a result of the

| ESP, no Section 7 consultation with FWS or NOAA Fisheries is required at this time. However,

| the issuance of a CP or COL is a separate action requiring a consultation with the appropriate

| agency, pursuant to Section 7 of the Endangered Species Act.

| The staff concludes the impacts on terrestrial and aquatic Federally listed threatened and

| endangered species from operation of the Grand Gulf ESP facility would be SMALL, and

| additional mitigation would not be warranted. The conclusion of SMALL impacts by the NRC
Operation Impacts at the Proposed Site

April 2006 5-31 NUREG-1817

staff is predicated on certain assumptions made by the staff. These include the current |

occurrence of Federally listed threatened and endangered species and critical habitat in the |

project area, the current listing status of such species, and the current designation of |

critical habitat. |

5.5 Socioeconomic Impacts

The socioeconomic impacts from operating the Grand Gulf ESP facility and from the activities

and demands of the operating workforce on the surrounding region include the potential

impacts on individual communities, the surrounding region, and minority and low-income

populations. To assess the potential impacts of operations, the staff evaluated the physical

impacts, population impacts, and impacts on community characteristics.

5.5.1 Physical Impacts

The potential physical impacts on the nearby communities resulting from operation of the new

unit or units includes noise, odors, exhaust, thermal emissions, and visual intrusions. |

5.5.1.1 Workers and Local Public

The town of Port Gibson, located about 10 km (6 mi) southeast of the Grand Gulf site, is a

small rural community that includes small businesses, houses, and farm buildings and has a

population of 1840, according to the 2000 U.S. Census (USCB 2004c). Because of Port

Gibson’s distance from the Grand Gulf ESP site, its residents would not experience any

physical impact from operation of the new unit or units. |

The new unit or units would produce noise from the operation of pumps, transformers, turbines, |

generators, and switchyard equipment. The noise levels would be controlled in accordance

with applicable local regulations. Most equipment would be located inside structures, reducing

the outdoor noise level.

Two types of cooling systems will be considered for a new facility at the Grand Gulf ESP site: 

natural draft cooling towers and mechanical draft cooling towers (SERI 2005a). Natural and |

mechanical draft cooling towers emit broadband noise. Therefore, the noise associated with

the cooling towers would be largely indistinguishable and nonobtrusive. The anticipated noise

levels from either of the cooling tower options are not expected to be significantly greater than

background levels. Noise levels below 60 to 65 dBA are not considered to be significant |

because these levels are not sufficient to cause hearing loss (NRC 1996).

Based on the PPE (see Appendix I), both natural and mechanical draft cooling towers have

anticipated noise levels of 55 dBA at 300 m (1000 ft). The proposed location of the cooling |
Operation Impacts at the Proposed Site

NUREG-1817 5-32 April 2006

towers would place them approximately 300 m (1000 ft) from the nearest site boundary on the

north side of the property. The resulting operational noise level from the addition of a new unit

or units would not significantly increase the noise level at the property line. Therefore, the noise

| level at the property line is expected to remain below the limit of 65 dBA recommended in

NUREG-1555 (NRC 2000a). In general, power plant sites do not result in offsite noise level

| increases of more than 10 dBA above background levels. Therefore, background noise levels

| are expected to range from 45 to 55 dBA at the nearest site boundary.

| Noise levels below 60 to 65 dBA are considered to be of SMALL significance (NRC 1996). 

Therefore, the noise impact at the nearest residence would be SMALL and no mitigation would

be warranted. 

Ambient noise heard by recreational users of Grand Gulf Military Park under normal conditions

| includes some noise from the GGNS Unit 1 plant. The noise level generated by the operation

of the new unit or units would not affect the recreational use of Grand Gulf Military Park.

In Section 2.7 of NRC Regulatory Guide 4.2 (NRC 1976), the staff states that an assessment

should be made of the ambient noise level within 8 km (5 mi) of any proposed nuclear facility. 

Particular attention is directed toward obtaining acoustic levels associated with high voltage

transmission lines. An assessment of the impact from the transmission system would be

studied at a suitable time within future planning work and after a decision has been made to

| proceed with the new additional capacity.

The new unit or units would have standby diesel generators and auxiliary power systems. Air

permits acquired for these generators would ensure that air emissions comply with regulations. 

In addition, standby diesel generators would be operated on a limited short-term basis.

5.5.1.2 Buildings

Operations activities would not affect any offsite buildings. Onsite buildings have been

constructed to safely withstand any possible impact, including shock and vibration, from

operations activities associated with the proposed activity. Except for GGNS Unit 1 structures,

no other industrial, commercial, or residential structures would be directly affected by the

| operation of a new ESP facility.

5.5.1.3 Roads

Commuter traffic would be controlled by speed limits. The access roads to the Grand Gulf ESP

site would be paved. Good road conditions and appropriate speed limits would minimize the

| noise level generated by the workforce commuting to the Grand Gulf site.
Operation Impacts at the Proposed Site

April 2006 5-33 NUREG-1817

5.5.1.4 Aesthetics

The nearest residential area is about 500 m (1650 ft) from the Grand Gulf ESP site and is

shielded by woods. Given this distance, residents near the site would not have a clear view of

the new unit or units. Some structures of the new facility may be visible from the Mississippi

River (for example, intake structure, cooling towers) and from Grand Gulf Military Park. Bluffs

on the site east of the Mississippi River are about 20 m (65 ft) above the average river level

(Entergy 2003c), and dense forest throughout the vicinity would help conceal the

new structures.

The reactor design and ancillary facilities (cooling water system) have not yet been selected. |

The natural draft cooling towers, if used, would be up to 168 m (550 ft) tall, so some visual |

impact would result. However, the existing cooling tower at GGNS is similar in height and is |

difficult to see from most vantage points offsite. Mechanical draft cooling towers would be |

considerably shorter: 18 m (60 ft). Either type of tower would generate a visible water vapor |

plume. Longest visible plumes would occur in the winter with an estimated average length of |

3.71 km (2.32 mi) for natural draft cooling towers and 2.18 km (1.36 mi) for mechanical draft |

cooling towers (SERI 2005a). Because the Grand Gulf ESP site is already aesthetically altered |

by the presence of an existing nuclear power plant (GGNS Unit 1) with a natural draft cooling |

tower along with its visual plume, only slight adverse impacts on visual aesthetics of the site |

and vicinity are expected from the operation of a new facility. |

As stated in Section 5.4.2, the full extent of the changes in the transmission system cannot be |

known until SERI initiates the Federal Energy Regulatory Commission process for connecting |

new large generation plants to the grid. If, as assumed in Section 4.4.1, existing transmission |

line rights-of-way are used, even significant widening of these rights-of-way and building of new |

transmission towers is unlikely to have more than a minor effect on visual aesthetics. |

During normal plant operation, the new unit or units would not use a large amount of chemicals

that would generate odors exceeding the odor threshold value.

5.5.1.5 Summary of Physical Impacts

Based on the information provided by SERI, staff interviews with local public officials, and its

own independent review, the staff concludes that the physical impacts of operation of the new

unit or units at the Grand Gulf ESP site would be SMALL, and additional mitigation measures |

beyond those identified by SERI would not be warranted. |

The conclusion of SMALL impacts by the NRC staff is predicated on certain assumptions made |

by the staff. These include mitigative actions identified to reduce physical impacts such as: |

cooling tower plume control; compliance measures to control noise, dust, and other air |

pollutants; and traffic management identified by SERI are undertaken. |
Operation Impacts at the Proposed Site

NUREG-1817 5-34 April 2006

5.5.2 Demography

| The demographic impacts from the operation of a new unit or units at the Grand Gulf ESP site

would be associated with employment related to the daily operation of the new unit(s) and with

resulting effects on the surrounding region.

| According to the SERI environmental report, approximately 1160 workers (SERI 2005a) would

| be required for the operation of the new unit or units, about 50 percent more than are currently

required for the existing GGNS Unit 1. A conservative estimate of 50 percent of these would be

expected to in-migrate to the region, accompanied by their families. Assuming an average

| family size of four, 2320 people could be expected to move to the region from other areas and

would represent both a source of income to the community and a potential demand on

community services, such as schools and police protection.

| The expected number of permanent workers needed to operate the new unit or units and their

families generally would be a small fraction of the total projected population growth in the

region. Assuming that the geographic distribution of new employees would be the same as for

| the existing unit, Table 5-4 shows the potential geographic distribution of new employees and

the potential percentage increase for each jurisdiction’s population represented by facilityrelated population if facility operations started today. Proportionally more new migrants,

however, are expected to reside in the Vicksburg area rather than in Port Gibson because of

| the wider availability of housing and services in Vicksburg (SERI 2005a).

Table 5-4. Potential Increase in Resident Population Resulting from Operations at the Grand

Gulf Early Site Permit Site

|

| Jurisdiction

Percent of Current

GGNS Workforce

by Location

ESP FacilityRelated

Increase in

Population

Year 2000

| U.S. Census

Population

Percentage

Increase in

Resident

Population

ESP FacilityRelated

Households

Year 2000

Vacant

Housing

Units

| Vicksburg 46.4 1,076 26,407 4.1 269 1,290

| Port Gibson 14.6 339 1,840 18.4 85 95

| Other locations

| Clinton 7.3 169 23,347 0.7 42 571

| Fayette 3.9 90 2,242 4.0 22 68

| Natchez 3.3 77 18,464 0.4 19 888

| Brookhaven 2.7 63 9,861 0.6 16 430

| Jackson 2.7 63 184,256 0.0 16 7,837

| Wesson 2.3 53 1,693 3.1 13 41

| Hazelhurst 1.7 39 4,400 0.9 10 158

| All Other 15.1 350 NA NA 88 NA 

| Total 100.0 2,319(a) 580

| (a) Difference between total of 2319 and SERI (2005a) assumption of 2320 is due to rounding.

ESP = early site permit

| GGNS = Grand Gulf Nuclear Station

| NA = not available

| Source of resident locations: SERI 2004a

| Source of Year 2000 U.S. Census Population: USCB 2004c
Operation Impacts at the Proposed Site

April 2006 5-35 NUREG-1817

Based on the information provided by SERI, staff interviews with local public officials, and their |

own independent review, the staff concludes that the demographic impacts of operation of the

new unit or units at the Grand Gulf ESP site on most of the region would be SMALL. However, |

if Port Gibson, Mississippi, were to attract new in-migrating population in the same proportion

as existing facility employees, the town would experience an 18 percent population increase,

which would be a LARGE demographic impact. |

The conclusion regarding the range of impacts by the NRC staff is predicated on certain |

assumptions made by the staff. These include not more than 1160 new operations workers at |

the Grand Gulf ESP site, not less than 50 percent of the operations workers would come from |

the region within 80 km (50 mi) of the Grand Gulf site, and most of the new workers would |

choose to live in the larger cities of the region. |

5.5.3 Social and Economic Impacts

The social and economic impacts on the surrounding region as a result of operating the Grand |

Gulf ESP facility were evaluated, assuming a 40-year operating license term. |

5.5.3.1 Economy

The main economic impacts resulting from new workers and their families on the area would be |

related to taxes, housing, and requirements for goods and services. Economic impacts related

to the operation of the new unit or units would be associated mainly with payment of the plant |

property taxes. 

A detailed description of local and regional employment trends is provided in Section 2.8. 

Annual 2004 county labor force data indicate that Claiborne County has an unemployment rate |

of 10.1 percent (Section 2.8.2.1). General trends for Claiborne and the contiguous counties |

indicate the total number of jobs across many of the surveyed industries have decreased from

1990 to 2000 (USCB 2004a, 2004b). Operation of a new ESP facility could generate jobs for |

the residents of the area. The addition of 1160 permanent workers traveling into the area

would also increase demand for commercial retail establishments, which would provide some

additional employment. The overall impact on the economy of the region (including Claiborne

County and surrounding counties–especially Vicksburg and Warren County) would be positive.

5.5.3.2 Taxes

The assessed value of the new unit or units would exceed that of the existing GGNS unit, which |

has depreciated with time. It is not possible at this time to estimate the actual taxes that would

be paid to the regional governments or the expenditures regional governments would incur to

accommodate the workforce. The expenditures by the regional governments would, in part, be

related to the size and age distribution of the families of the new employees. Based on the
Operation Impacts at the Proposed Site

NUREG-1817 5-36 April 2006

assumption that the new employees would come from outside the region, the regional

governments would experience both outflows and inflows of monies as a result of the operation

of the new unit or units. Expenditures would be related to the impact on the local and regional

infrastructure because of the increased use of the school, recreational, medical, fire and police,

| and transportation systems. The types of taxes and their bases can be addressed and are

presented below.

Sales, Use, and Income Taxes

Sales, use, and income taxes would be generated by retail expenditures (restaurants, hotels,

and merchant sales) of operations workers. Although there is a small local sales and use tax,

the State would collect most of these, both from individual workers and from corporate entities

in the general region of the site. No estimate is available of the day-to-day expenditures during

operations that would occur in the region.

Property Taxes

The jurisdictions shown in Table 5-4 would benefit from additional property tax revenues from

two sources associated with the Grand Gulf ESP facility: property tax on the new unit or units

and property tax on land owned by the new employees. Because of the manner in which

Mississippi treats the tax base of nuclear power facilities, local property taxes might or might not

be levied for the increase in value of the Grand Gulf site because of the new unit or units. The

property tax payments to Claiborne County are discussed in Sections 2.8 and 4.5, and are

| identified as a potential beneficial impact for the state of Mississippi or for Claiborne County,

depending on tax treatment of the new plant. The addition of the new unit or units to the Grand

Gulf site would substantially increase the property tax payments in the State.

| The existing GGNS unit has contributed 83 percent of the property taxes paid to Claiborne

| County over the past decade. The construction and operation of a new nuclear unit or units are

| expected to maintain the very high percentage of the property taxes in Claiborne County paid

by Entergy.

The potential effect of future electric utility deregulation within Mississippi is not known. 

However, if Mississippi were not to regulate the Grand Gulf ESP facility as a public utility, it is

| reasonable to conclude the facility could be treated as an ordinary corporate asset subject to

normal local property taxation. If so, the new unit or units would result in a substantial increase

in property tax payments to Claiborne County.

If the final capital cost were in the range of $1000 per installed kilowatt, the maximum capacity 

3000 MW(e) facility would (at completion) have an approximate capital value of $3 billion. At

Claiborne County’s current property tax rate of 65.01 mills and 15 percent assessment ratio for

nonresidential property (SERI 2004a), the tax yield would be about $29 million per year, a very
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April 2006 5-37 NUREG-1817

significant positive impact. Even if the new nuclear facility were taxed and the funds distributed |

as with the existing GGNS, the payment in lieu of taxes to Claiborne County would be about |

$7.8 million per year, increasing county revenues by about 83 percent, still a LARGE effect. |

Other nearby counties would see much smaller benefits from other taxes. The expected |

impacts on the economy and tax revenues in Claiborne County would be LARGE and |

beneficial. |

The conclusion of LARGE beneficial impacts in Claiborne County is predicated on certain |

assumptions made by the staff. These include not more than 1160 new operations workers |

would be employed at the Grand Gulf ESP site, not less than 50 percent of the operations |

workers would come from the region within 80 km (50 mi) of the Grand Gulf site, most of the |

new workers would choose to live in the larger cities of the region, and there are no significant |

changes in the terms and conditions for taxability of real property under Mississippi tax law. |

5.5.3.3 Summary of Social and Economic Impacts |

Based on the information provided by SERI, staff interviews with local public officials, and its |

own independent review of data on the regional economy and taxes, the staff concludes that |

the impacts on the regional economy of operating the new unit or units at the Grand Gulf ESP |

site on most of the region would be SMALL, with a possible MODERATE beneficial impact in |

Warren County. Under current Mississippi tax law, it appears that Claiborne County would |

receive annual property taxes or payments in lieu of taxes equal at least to an increase of |

$7.8 million (83 percent of the current county budget) and perhaps much more, depending how |

the new plant would be treated for tax purposes. Taken together with the jobs created in the |

region, this would be a LARGE beneficial impact in Claiborne County. |

The conclusion of LARGE beneficial impacts by the NRC was predicated on certain |

assumptions made by the staff; these include: that there would be no more than 1160 new |

operations workers at the Grand Gulf ESP site; that no less than 50 percent of these workers |

would come from the 80-km (50-mi) region surrounding the site; that new workers would tend to |

live in the larger communities in the region; and that there are no significant changes in |

Mississippi tax law, especially the terms and conditions for taxability of real property. The NRC |

staff would have to confirm these assumptions at the CP or COL stage and determine whether |

there would be any new and significant information that would change this conclusion. |

5.5.4 Infrastructure and Community Services

Infrastructure and community services include transportation, recreation, housing, public

services, and education.
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NUREG-1817 5-38 April 2006

5.5.4.1 Transportation

Roads within the vicinity of the Grand Gulf ESP site would experience a temporary increase

in traffic at the beginning and the end of the workday period. However, the current road

| network has sufficient capacity to accommodate the increase, as discussed in Section 4.5.4.1.

| Section 4.5.4.1 shows a number of permanent changes to the regional and local transportation

network that would reduce any potential adverse impacts generated by the influx of

| 3150 construction workers during construction of one or more new units. These permanent

changes would also reduce or eliminate any potential adverse impacts that could be generated

| by the operating workforce of 1160 for the new unit or units, 50 percent of whom are expected

to have relocated with their families into the region.

5.5.4.2 Recreation

The facility-related population increase in the potentially affected counties is expected to be

| about 2320 people. To accommodate normal increases in population, which are expected to be

much larger, the surrounding counties would need to address and fund new recreational areas

as they update their comprehensive plans. The GEIS (NRC 1996) concludes the impacts of

existing employees and their families on parks and other recreational areas within a typical

| region are small. This conclusion likely would also apply to the employees of the new ESP unit

or units and their families who would relocate to the area because they represent a small

fraction of the projected population growth for the area.

A detailed description of local tourism and recreation is provided in Section 2.8. Because of the

proximity of the Grand Gulf Military Park to the north of the Grand Gulf ESP site, it is possible

that increased traffic resulting from the influx of site workers would indirectly affect the traffic

flow to Grand Gulf Military Park, and that there would be minor effects on noise and visual

aesthetics in the park. However, the majority of tourists visit the park on the weekends when

fewer people report for work at the Grand Gulf ESP site (SERI 2004a, Attachment 14). In

addition, the traffic associated with the Grand Gulf site is limited to specific times of the day,

during shift changes, which would minimize the impact of potential Grand Gulf ESP site traffic

on the Grand Gulf Military Park. Case studies conducted during operation of several nuclear

| power facilities indicated no adverse impacts on local tourism and recreation as a result of the

operation of existing nuclear power plants (NRC 1996).

5.5.4.3 Housing

The number of housing units required to support the expected permanent workforce migrating

into the area would be 580, half of the 1160 new employees (see Table 5-4). In Port Gibson,

plant-related migration would absorb a substantial portion of the vacant housing stock, if today’s

residence pattern of GGNS workers were the same for new workers and if the population

increase were to happen today. There is no accurate way to estimate the number of housing
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April 2006 5-39 NUREG-1817

units that would be available in the region in the year 2030, the year a new ESP facility would

be expected to begin operations (SERI 2005a). However, the counties in the vicinity of the |

Grand Gulf ESP site and within the region are addressing the needs of the projected increases

in population and an adequate number of units likely would be available, especially in the larger

towns. Little new housing seems to have been recently added in Claiborne County, as |

discussed in Section 5.1.1, although nearby larger communities are keeping pace with housing |

demand (Scott 2004). Because the new workforce incomes would be high relative to other |

incomes in the region, it can be expected that the housing purchases would be on the high end

of the price range. The new workers and their families would be about 9.4 percent of the

population growth SERI (2005a) has projected for the area within 80 km (50 mi) over the next |

30 years (Table H-2 in Appendix H). Therefore, the impact of the property taxes paid for

housing by these families overall would be a small benefit to the region, but possibly locally

more important in Port Gibson and Vicksburg, Mississippi, if they concentrate in those cities.

Currently, 100 to 200 additional outage workers conducting refueling of the GGNS Unit 1 |

reactor are onsite for a period of 30 to 40 days per outage (SERI 2005a). It is expected the |

planned outages for the new unit or units would be scheduled so that multiple units would not

be worked on simultaneously. This would also reduce the potential for exceeding the

availability of short-term housing in the immediate vicinity of the Grand Gulf ESP site. The

temporary outage staff for the existing GGNS typically stays in area hotels or manufactured |

home and recreational vehicle parks dispersed throughout the region. Therefore, no single |

community would be overburdened by the influx of temporary workers. It is expected that the |

increased frequency of the temporary outage staff would not significantly affect the region.

5.5.4.4 Public Services

Water Supply and Waste Treatment

Detailed information regarding the current sewer and water services available at the Grand Gulf |

site is provided in Section 2.8.2.6. SERI currently operates an onsite water and sewer system |

for treatment of sanitary waste from GGNS Unit 1. Additional water and sewage treatment |

facilities would be constructed as part of a new facility to support future operations. However,

the designs for water and sewer treatment facilities for the ESP facility have not been selected. 

Because a new facility would use onsite water and sewer services, the operation of a new

facility at the Grand Gulf site would not burden public utilities in surrounding communities. In

general, case studies indicate minimal impact on public utilities resulting from plant operation |

(NRC 1996).

The in-migration of additional employees and their families would increase the demand for

public utilities in the communities where these employees reside. As was the case with the

construction of GGNS Unit 1, it is expected these workers would reside in or around the more

populous areas such as Vicksburg, Mississippi, because of the public utilities and other services
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NUREG-1817 5-40 April 2006

available. The water and sewer services in Vicksburg are currently at 70 percent of total

| capacity (SERI 2004a). Therefore, the addition of plant personnel to this or other comparable

communities would not be expected to overburden public utilities. The possible exception

| would be Port Gibson where, if population increased by 18.4 percent (Table 5-4), water use

could increase to close to the maximum capacity of the system. Because operational staff

in-migrating to the region for a new facility would likely settle in numerous surrounding

| communities, the potential impacts on public utilities of any one community would be expected

to be minimal. Increases in sales, property, and income taxes generated by the population

in-migrating to specific communities would at least partially offset costs associated with any

upgrades a community may find necessary. The impacts of relocated families on these water

and sewer systems would not be significant.

Police, Fire, and Medical

The police and fire departments within 16 km (10 mi) of the Grand Gulf ESP site are part of the

| existing emergency response plan for the existing GGNS Unit 1. The Claiborne County Sheriff

and other local police departments are responsible for the proper evacuation of the area in the

event of an emergency at the Grand Gulf site. This would continue to be the case should the

new unit or units become operational. Despite the transfer of funds from the State government

to Claiborne County, there is substantial local concern about the adequacy of emergency

resources to implement the current evacuation plan and the ability of local officials to carry it out

(Scott 2004).

The nearest medical facilities generally consist of local physicians’ offices and the 32-bed

hospital in Port Gibson, Mississippi. However, major medical facilities are available in

Vicksburg, Natchez, and Jackson, Mississippi. These facilities are readily accessible to county

residents and have held successful emergency drills with the GGNS. The surrounding counties

assess the need for additional medical, fire, and police facilities and add new facilities or

expand existing facilities as needed. For example, the Warren County hospitals and medical

facilities recently have accommodated economic and population growth from 1800 new jobs at

two Japanese-owned companies (Scott 2004). The increase of 580 (half of the total 1160) new

resident employees and their families would represent a small fraction of the expected

population growth in the multi-county region around the Grand Gulf ESP site. However if new

residents were to concentrate in Claiborne County, the increase in Claiborne County population

might be quite significant relative to the current population. Therefore, while in general no

| unforeseen demands on medical facilities would result from the operation of the new unit or

| units, there may be increased demands for beds in Port Gibson’s hospital as well as increased

| hours of operation. Financing the potential hospital upgrades would require additional revenue

(Scott 2004).

Detailed information concerning the capacity of the hospitals in Claiborne County and the

adjacent Mississippi counties is provided in Section 2.8.2.6. It is expected that a majority of the
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April 2006 5-41 NUREG-1817

future employees will reside in more populous areas located in neighboring counties (for

example, Vicksburg, Warren County). Therefore, the influx of plant workers is not expected to

overburden Claiborne County health or social services. Case studies of several nuclear power

plants show only a small impact on local social services associated with the influx of plant

workers (NRC 1996).

5.5.4.5 Education

Table 2-18 shows the number of schools within the Mississippi counties surrounding Claiborne |

in the Grand Gulf ESP site area. As was the case with GGNS Unit 1, new workers would likely

move to the more populous areas in the surrounding communities where they would have

access to more developed public services. Workers with school-aged children would be

interested in communities with good school districts. The largest school district near the Grand

Gulf ESP site is in Vicksburg, Mississippi. The current student population at Vicksburg is 9180

(NCES 2002). Given sufficient lead times, school officials in Warren County are not concerned

about absorbing the potential increase in students (Scott 2004). The impact on Vicksburg

schools would likely be small.

Port Gibson has only 2011 students (Section 2.8.2.7). If 14.6 percent of new workers moving to |

the area located in Port Gibson and their family size is assumed to be four (two of whom are

students), the impact in Port Gibson would be 169 students, an 8.4 percent increase. This |

would be a moderate impact (assuming some impact assistance from the State) on Port Gibson |

schools were it to happen. Part of this increase could be absorbed by private schools located in

the area. Any adverse impact on local school districts because of the influx of plant workers |

into a community would likely be at least partially offset by increased sales, personal property,

and income tax revenues paid by facility personnel. Overall, the impacts on education in

Claiborne County would be moderate. |

5.5.4.6 Summary of Infrastructure and Community Services |

Based on information supplied by SERI, staff interviews conducted with public officials in |

Claiborne, Jefferson, and Warren counties, and staff review of data concerning the current |

availability of services and current state and community planning efforts, the staff concludes |

that the operation impacts on the regional infrastructure and community services would be |

SMALL in most of the region. The estimated workforce of 1160 persons would have a SMALL |

effect on the transportation network in the vicinity and region because several permanent |

transportation mitigation measures are being implemented that will remove most remaining |

bottlenecks. The site is relatively isolated, industrial in nature, and well masked by forest in |

most directions so the impacts on aesthetics would be SMALL, as would the impacts on |
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NUREG-1817 5-42 April 2006

| recreation. The impacts on public services and infrastructure would be SMALL throughout the

| region, unless Claiborne County draws a substantial share of the in-migrating operations

| workforce, which is not expected. In that case, the impacts on housing and education in

| Claiborne County could be MODERATE.

| The conclusion of MODERATE impacts by the NRC was predicated on certain assumptions

| made by the staff; these include: that there would be no more than 1160 new operations

| workers at the Grand Gulf ESP site; that no less than 50 percent of these workers would come

| from the 80-km (50-mi) region surrounding the site; that new workers would tend to live in the

| larger communities in the region (but could still result in a significant relative increase of

| population in Claiborne County); and that the state would provide some financial help if the

| school system were seriously affected by in-migration. The NRC staff would have to confirm

| these assumptions at the CP or COL stage and determine whether there is any new and

| significant information that would change this conclusion.

5.5.5 Summary of Socioeconomic Impacts

Based on information supplied by SERI, staff interviews conducted with public officials in

Claiborne, Jefferson, and Warren counties concerning the current availability of services, and

additional taxes that would likely compensate the need for additional services, the staff

| concludes that the operations impacts on the local economy would be beneficial and SMALL in

| most of the region and probably MODERATE and beneficial in Warren County (Vicksburg). 

The estimated workforce of 1160 would have a SMALL effect on the transportation network in

the vicinity and region because permanent transportation mitigation measures proposed for the

| construction of the new unit or units would also result in much reduced transportation-related

| impacts during operation of the new unit or units. The effect on tax revenues would be

beneficial and SMALL except for property tax receipts in Claiborne County, which could be

| beneficial and LARGE. The site is relatively isolated, industrial in nature, and well masked by

forest in most directions so the impacts on aesthetics would be SMALL, as would the impacts

on recreation. The impacts on public services and infrastructure would be SMALL throughout

the region, unless Claiborne County draws a substantial share of the in-migrating construction

workforce, which is not expected. In that case, the impacts on housing and education in

| Claiborne County could be MODERATE and adverse, but more than likely would be more than

| offset by LARGE tax receipts.

| The conclusion of LARGE to SMALL beneficial impacts and SMALL to MODERATE adverse

| impacts by the NRC staff is predicated on certain assumptions made by the staff. These

| include not more than 1160 new operations workers would be employed at the Grand Gulf ESP

| site, not less than 50 percent of the operation workers would come from the region within 80 km

| (50 mi) of the Grand Gulf site, most of the new workers would choose to live in the larger cities

| of the region, and there are no significant changes in Mississippi tax law, especially the terms

| and conditions for taxability of real property. 
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April 2006 5-43 NUREG-1817

5.6 Historic and Cultural Resources Impacts

The National Environmental Policy Act of 1969 (NEPA) requires Federal agencies to take into

account the potential effects of their undertakings on the cultural environment, which includes

archaeological sites, historic buildings, and traditional places important to local populations. 

The National Historic Preservation Act of 1966 (NHPA), as amended through 1992, also

requires Federal agencies to consider impacts on those resources if they are eligible for listing |

on the National Register of Historic Places (such resources are referred to as “Historic

Properties” in NHPA). As outlined in “Coordination with the National Environmental Policy Act,”

36 CFR 800.8, the NRC is coordinating compliance with Section 106 of the NHPA in meeting

the requirements of NEPA.

Because all ground-disturbing activities that could have an impact on historic or archaeological

resources would probably occur during the construction phase, there would be limited potential

for impacts during operation of one or more additional units at the Grand Gulf ESP site. The |

NRC staff therefore concludes that the potential impacts on historic and cultural resources |

would be SMALL. The conclusion of SMALL impacts by the NRC staff is predicated on the |

assumption that SERI will develop procedures regarding protection of historic and cultural |

resources that would be incorporated into the site-wide Excavation and Backfill Work |

Procedures, which will involve an immediate stop work order should archaeological, historical, |

or other cultural resources be uncovered during excavation. The construction supervisor would |

be responsible for ensuring the work stoppage and for notifying the Environmental Compliance |

Coordinator of an inadvertent discovery. If such a discovery is made, site personnel would be |

instructed to notify the State Historic Preservation Officer and would consult with him or her in |

conducting an assessment of the discovery to determine if additional work is needed. If an |

applicant submits a CP or COL application referencing this ESP, the NRC staff’s review of such

an application would be a separate undertaking requiring further consultation pursuant to |

Section 106 of the NHPA. |

5.7 Environmental Justice Impacts

Environmental justice refers to a Federal policy under which each Federal agency identifies and

addresses, as appropriate, disproportionately high and adverse human health or environmental

effects of its programs, policies, and activities on minority or low-income populations. On

August 24, 2004, the Commission issued its policy statement on the treatment of environmental

justice matters in licensing actions (69 FR 52040). Section 2.10 discusses the locations of

minority and low-income populations around the Grand Gulf ESP site and within the 80-km

(50-mi) radius.

As discussed in Section 4.7, the staff examined the geographic distribution of minority and

low-income populations recorded during the 2000 U.S. Census (USCB 2004b, 2004c) within |
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NUREG-1817 5-44 April 2006

80 km (50 mi) of the Grand Gulf ESP site, encompassing 25 counties and parishes. The

| analysis was also supplemented by field inquiries and outreach to the planning department and

social service agencies in Claiborne, Warren, and Jefferson counties.

| Specifically, in the case of the Grand Gulf ESP, announcements of public meetings were made

| in the Port Gibson Reveille and Jackson Clarion-Ledger. Press releases announcing the

| meetings were forwarded to the Arkansas Democrat, the Columbus (MS) Telegram, Jackson

| (MS) Clarion-Ledger, Port Gibson (MS) Reveille, and Vicksburg (MS) Post newspapers, and to

| WJTV (Jackson) and WVUE-TV (New Orleans). In addition to public meetings, at the request

| of staff, the local county governments invited a number of local government and social services

| officials to additional meetings that were held in Port Gibson, Fayetteville, and Vicksburg.

Minority and low-income areas identified from the census block group data are shown

graphically in Figures 2-12 and 2-13, respectively. However, it is also clear from examining

census block group data that most of the counties and parishes within 32 km (20 mi) of the

Grand Gulf ESP site have large African-American populations, whether or not they meet the

usual plus-20 or -50 percent criteria.

| The scope of the review as defined in NRC guidance (NRC 2001, 2004b; 69 FR 52040) should

include an analysis of the impacts on minority and low-income populations, the location and

significance of any environmental impacts during operations on populations that are particularly

sensitive, and any additional information pertaining to mitigation. The descriptions to be

provided by this review should state whether the impacts are likely to be disproportionately high

| and adverse. The review should also evaluate the significance of such impacts.

With the locations of minority and low-income populations identified, the staff proceeded to

evaluate whether the environmental impacts of the proposed action could affect these

| populations in a disproportionate manner. Based on staff guidance (NRC 2001, 2004b;

69 FR 52040), air, land, and water resources within about 80 km (50 mi) of the Grand Gulf ESP

site were examined. Within that area, potential environmental impacts could affect human

| populations. All physical environmental impacts would be SMALL, and the socioeconomic

| impacts would vary from LARGE beneficial to MODERATE adverse.

5.7.1 Environmental Impacts

| The pathways through which the environmental impacts associated with the new unit or units

| could affect human populations are discussed in Sections 5.7.2 and 5.7.3. The staff evaluated

whether minority and low-income populations could be disproportionately affected by these

| impacts. The staff found no unusual health conditions or resource dependencies or practices,

such as subsistence agriculture, hunting, or fishing, through which the populations could be

| disproportionately affected (see Section 2.10). In addition, the staff did not identify any

location-dependent disproportionate impacts affecting these minority and low-income
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April 2006 5-45 NUREG-1817

populations. The staff concludes that offsite impacts on minority and low-income populations |

from operating one or more new units at the Grand Gulf ESP site would be minor, and no |

additional mitigation would not be warranted. |

The conclusion of SMALL impacts by the NRC staff is predicated on certain assumptions made |

by the staff. These include there will not be any significant demographic changes before |

additional units are added to the Grand Gulf site and there are no significant resource |

dependencies or pre-existing conditions among the minority and low-income population that |

have not been identified. |

5.7.2 Human Health Impacts

Operation of the new facility would result in slight contributions to radiation dose to members of

the public living in the vicinity of the site, far below that associated with natural radiation

background levels.

As presented in Section 5.9, the critical pathways to humans for routine radiation releases from

facilities at the Grand Gulf ESP site are exposure from air, inhalation of contaminated air,

drinking milk from a cow that feeds on open pasture near the site, eating vegetables from a

garden near the site, and eating fish caught in the Mississippi River. The results of the normal

operation dose assessments indicate that the maximum individual dose for these pathways was

found to be insignificant, well below the regulatory guidelines in Appendix I of 10 CFR Part 50

and the regulatory standards of 10 CFR Part 20.

The evaluation of postulated accidents is provided in Section 5.10 and demonstrates that

radiological consequences of these accidents would meet the site acceptance criteria of

10 CFR 50.34 and 10 CFR Part 100 for the exclusion area boundary and low population zone

boundary. In demonstrating compliance with these criteria, an adequate level of protection

would be provided. There would be no significant adverse health impacts on members of the |

public, and, therefore, there would be only minimal negative and disproportionate health

impacts on minority and low-income members of the public. |

The conclusion of SMALL impacts by the NRC staff is predicated on certain assumptions made |

by the staff. These include there will not be any significant demographic changes before any |

additional units are added to the Grand Gulf site, regional populations of minority and low- |

income populations will remain in the same geographic locations, and there are no significant |

resource dependencies or pre-existing conditions among the minority and low-income |

population that have not been identified. |
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NUREG-1817 5-46 April 2006

5.7.3 Socioeconomic Impacts

Potential adverse socioeconomic impacts during operations include potential adverse impacts

on air quality, aesthetics, schools, transportation, public safety, social services, public utilities,

and recreational resources. None of the potential physical impacts attributable to operation of a

| new facility were judged to be significant to most of the region. SERI would provide some

| additional revenues to support emergency services in Claiborne County and Port Gibson (see

| Section 5.1.1). However, depending on where new in-migrating employees decide to live,

Claiborne County might have to upgrade several components of its social services and public

utilities infrastructure. It is not clear how the new nuclear facility would be treated for property

tax purposes, so it is not clear whether Claiborne County would receive property taxes, sales,

and use taxes, or other taxes and public monies commensurate with the costs of its additional

| emergency management and public services obligations. However, under current Mississippi

| tax law, it appears that Claiborne County would receive at least $7.8 million per year if the new

| nuclear facility were treated the same as the existing GGNS, and considerably more if it were

| treated as an ordinary industrial asset. A LARGE net financial benefit would be realized by

| local residents and taxpayers, most of whom are minority and low-income persons.

| The conclusion of LARGE beneficial impacts is predicated on certain assumptions made by the

| NRC staff. These include: not more than 1160 new operations workers would be employed at

| the Grand Gulf ESP site; not less than 50 percent of the operations workers would come from

the region within 80 km (50 mi) of the Grand Gulf site; most of the new workers would choose

| to live in the larger cities of the region; there are no significant changes in the terms and

| conditions for taxability of real property under Mississippi tax law; and regional populations of

| minority and low-income populations will remain in the same geographic locations. 

5.7.4 Summary of Environmental Justice Impacts

| Taken together, the impacts of plant operations on environmental justice would be SMALL for

| environmental and human health impacts because no environmental pathways or health and

| other preconditions of the minority and low-income population were found that would lead to

| adverse and disproportionate impacts. The socioeconomic impacts would be LARGE and

| beneficial because local tax burdens and access to public services in Claiborne County would

| likely greatly improve, depending on the level of public sector obligations imposed by new

| residents and the level of tax revenues provided by the new units. 

| The conclusion of LARGE beneficial impacts is predicated on certain assumptions made by the

| NRC staff. These include not more than 1160 new operations workers would be employed at

| the Grand Gulf ESP site, not less than 50 percent of the operation workers would come from

the region within 80 km (50 mi) of the Grand Gulf site, most of the new workers would choose

| to live in the larger cities of the region, there are no significant changes in the terms and

| conditions for taxability of real property under Mississippi tax law, and regional populations of
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April 2006 5-47 NUREG-1817

minority and low-income populations will remain in the same geographic locations. The NRC |

staff would have to confirm these assumptions at the CP or COL stage and determine whether |

there is any new and significant information that would change this conclusion. |

5.8 Nonradiological Health Impacts

This section discusses the nonradiological health impacts of operating the proposed new unit(s)

at the Grand Gulf ESP site. Health impacts on the public from the cooling system, noise |

generated by unit operations, and EMFs are discussed. Health impacts from the same sources

are also evaluated for workers at the new unit. The health impacts from radiological sources |

during operations are discussed in Section 5.9.

5.8.1 Thermophilic Microorganisms

The SERI environmental report (SERI 2005a) noted thermal discharges to the Mississippi River |

would result from the use of cooling towers. Such discharges have the potential to increase the

growth of thermophilic microorganisms both in the cooling tower and river. The types of

thermophilic microorganisms sometimes found where elevated moist temperatures exist are

Salmonella sp., Psudomonas aeruginosa, Legionella sp., and free-living amoebae of the genera

Naegleria and Acanthamoeba. Serious illness and even death can occur when there is high |

exposure to these microorganisms.

As described in the GEIS (NRC 1996), nuclear power plants that use cooling ponds, lakes, or

canals and those that discharge to “small rivers” have the greatest chance of affecting the

public from increases in thermophilic microbial populations. A small river is defined as one with |

an average flow rate of less than 2830 m3/s (100,000 ft3/s). The average flow of the Mississippi

River between the years 1973 and 1999 was about 20,700 m3/s (730,000 ft3/s) (SERI 2005a)

and, therefore, does not meet the criterion of a small river. GGNS Unit 1 and one or more new |

units would be discharging thermal effluent into the river. SERI reviewed data from the Center

of Disease Control for the years 1991 through 2000 and found no incidences of waterborne

diseases in Mississippi that were associated with the Mississippi River (SERI 2005a). |

5.8.2 Noise

In the GEIS (NRC 1996), the staff discusses the environmental impacts of noise at existing

nuclear power plants. Common sources of noise from plant operation include cooling towers,

transformers, and loud speakers with intermittent contributions from auxiliary equipment. 

These noise sources are generally sufficiently distant from the plant boundaries that the noise

generated by the plant is attenuated to near ambient levels before reaching critical receptors

outside the plant boundary.
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NUREG-1817 5-48 April 2006

GGNS Unit 1 has a closed-cycle cooling system that uses a natural draft cooling tower. This

system does not contribute significantly to noise at the plant site or at the plant boundary. 

| SERI’s environmental report (SERI 2005a) specifies that additional units at the proposed Grand

Gulf ESP site would be cooled by wet cooling towers. If the ESP is approved and cooling

towers are used at the site, the towers would be the primary noise source on the site in addition

to the existing cooling tower for GGNS Unit 1.

| Sound surveys made prior to startup of GGNS Unit 1 showed that ambient noise levels at the

| site generally varied from about 40 to 60 dBA during the course of a day (SERI 2005a). 

| SERI (2005a) does not indicate any more recent sound surveys. Based on the PPE cooling

| tower noise level of 55 dBA at 300 m (1000 ft) for the existing cooling tower, the staff estimates

that the background noise level at the exclusion area boundary closest to the postulated

| location for new cooling towers has increased by less than 1 dBA, an increase in the

background noise level that would not be perceptible.

At its closest point of approach, the site fence line is approximately 300 m (1000 ft) from the

| postulated location of the cooling towers at the Grand Gulf ESP site. Using this distance, the

| PPE cooling tower noise specification and four linear mechanical draft cooling tower units, the

| noise level at the closest point on the fence line is expected to increase to about 62 dBA. The

| noise level at 500 m (1650 ft), the closest residence, would be less than 60 dBA, and the noise

level at 800 m (0.5 mi) from the cooling towers is expected to be about 55 dBA. For context,

| Tipler (1982) lists the sound intensity of a quiet office as 50 dBA, normal conversation as

| 60 dBA, busy traffic as 70 dBA, and a noisy office with machines or an average factory as

| 80 dBA. Construction noise (at 3 m (10 ft)) is listed as 110 dBA, and the pain threshold

is 120 dBA .

| According to the GEIS (NRC 1996), noise levels below 60 to 65 dBA are considered to be of

small significance. More recently, the impact of noise was considered in the Generic

Environmental Impact Statement on Decommissioning of Nuclear Facilities, Supplement 1

Regarding the Decommissioning of Nuclear Power Reactors (NRC 2002a). In that document,

the criterion for assessing the level of significance was not expressed in terms of sound levels. 

Rather, the level of significance was based on the effect of noise on human activities and

| threatened or endangered species. The criterion in NUREG-0586 Supplement 1 (NRC 2002a)

is stated as follows:

The noise impacts of... are considered detectable if sound levels are sufficiently high to

disrupt normal human activities on a regular basis. The noise impacts ... are considered

destabilizing if sound levels are sufficiently high that the affected area is essentially

unsuitable for normal human activities, or if the behavior or breeding of a threatened or

endangered species is affected.
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April 2006 5-49 NUREG-1817

In addition, the U.S. Department of Housing and Urban Development, as set forth in |

24 CFR 51.101(a)(8), considers day-night average exterior noise levels 65 dBA and below to be |

acceptable for residential areas.

On these bases, the staff concludes that the potential impacts of noise resulting from operation

of additional nuclear power plants with cooling systems meeting the noise criteria of the PPE

(see Appendix I) would be minor at the Grand Gulf ESP site.

5.8.3 Acute Effects of Electromagnetic Fields

EMFs are produced by electrical devices including transmission lines. Two issues related to the

health effects of EMFs are addressed in some detail in the GEIS (NRC 1996). Those issues

are acute effects (shock hazard) and chronic effects (effects of long-term exposures to EMF).

Acute effects can result from direct contact with transmission lines. Transmission line

construction practices minimize public access to the lines. Acute effects can also be caused by

induced currents. The 1981 revision of National Electric Safety Code (NESC) added criteria

related to construction of transmission lines to minimize potential impacts associated with

induced currents. Section 3.7 of SERI’s environmental report (2005a) states that the existing |

transmission and distribution system serving GGNS Unit 1 is adequate for at least an additional |

1311 MW(e) generating capacity. Should a new plant with capacity greater than 1311 MW(e)

be proposed, SERI would conduct a study to determine the adequacy of the transmission and |

distribution system existing at that time.

SERI (2005a) has not asserted that the existing transmission and distribution system meets |

NESC criteria for induced currents or that modifications to the existing system would comply

with the relevant local, State, and industry standards including NESC and various American |

National Standards Institute/Institute of Electrical and Electronics Engineers standards. As a

result, the staff cannot come to a conclusion on potential acute impacts of EMFs and this issue |

is not considered to be resolved. |

5.8.4 Chronic Effects of Electromagnetic Fields

Research on the potential for chronic effects from 60-Hz EMFs from energized transmission |

lines was reviewed in the GEIS (NRC 1996). At that time, research results were not conclusive. |

The potential for chronic effects from these fields continues to be studied and consensus

results are still outstanding. The National Institute of Environmental Health Sciences (NIEHS)

directs related research through the DOE. An NIEHS report (NIEHS 1999) contains the |

following conclusion:

The NIEHS concludes that ELF-EMF [extremely low frequency-EMF] exposure cannot |

be recognized as entirely safe because of weak scientific evidence that exposure may
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NUREG-1817 5-50 April 2006

pose a leukemia hazard. In our opinion, this finding is insufficient to warrant aggressive

regulatory concern. However, because virtually everyone in the United States uses

| electricity and, therefore, is routinely exposed to ELF-EMF, passive regulatory action is

warranted such as a continued emphasis on educating both the public and the regulated

| community on means aimed at reducing exposures. The NIEHS does not believe that

other cancers or non-cancer health outcomes provide sufficient evidence of a risk to

| currently warrant concern.

This statement is not sufficient to cause the staff to consider the potential impact as significant

| to the public. However, because conclusive information is not available, this issue is not

| considered to be resolved.

5.8.5 Occupational Health

In general, human health risks for the operation of new nuclear units are expected to be

dominated by occupational injuries (for example, falls, electric shock, asphyxiation) to workers

engaged in activities such as maintenance, testing, and facilities modifications. Historically,

actual injury and fatality rates at nuclear reactor facilities have been lower than the average

U.S. industrial rates. Occupational injury and fatality risks are reduced by adherence to NRC

and Occupational Safety and Health Administration (OSHA) safety standards, practices, and

procedures. Appropriate State and local statutes must also be considered when assessing the

occupational hazards and health risks for operation of new nuclear units. The staff assumes

adherence to NRC, OSHA, and State safety standards, practices, and procedures for operation

of new nuclear units.

Occupational health impacts from thermophilic microorganisms would be the same as those

| discussed in Section 5.8.1. Health impacts on workers from noise and EMFs would be

| monitored and controlled in accordance with applicable OSHA regulations.

5.8.6 Summary of Nonradiological Health Impacts

| The staff evaluated health impacts on the public and the workers. Health risks to workers are

expected to be dominated by occupational injuries at rates below the average U.S. industrial

| rates. Health impacts on the public and workers from thermophilic microorganisms and noise

generated by operations would be minimal. Based on information provided by SERI and the

| NRC staff’s independent review, the staff concludes that the potential impacts of

| nonradiological effects resulting from the operation of one or more new nuclear units as defined

| in the environmental report (SERI 2005a) would be SMALL, and additional mitigation would not

| be warranted. The staff does not come to conclusions on acute and chronic impacts of EMFs;

| consequently, these issues are not resolved.
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April 2006 5-51 NUREG-1817

5.9 Radiological Impacts of Normal Operations

This section addresses the radiological impacts of normal operations of the new unit(s),

including a discussion of the estimated radiation dose to a member of the public and to the

biota inhabiting the area around the new unit(s). Estimated doses to workers at the new unit(s)

are also discussed. Radiological impacts were determined using the PPE approach where the

bounding direct radiation and liquid and gaseous effluent were used in the evaluation (see

discussion in Section 3.2.3).

5.9.1 Exposure Pathways

Using the PPE, SERI’s environmental report provided a list of fission and activation products |

that may be released in gaseous emissions and liquid effluents from the new unit(s) (see |

SERI 2005a, Tables 3.0-7 and 3.0-8). The impacts from releases and direct radiation were |

evaluated by considering the probable pathways to individuals, populations, and biota near the |

additional unit(s). The highest dose from the major exposure pathways were evaluated for a |

given receptor. The exposure pathways, described in Regulatory Guides 1.109 and 1.111 |

(NRC 1977a, 1977b), are illustrated in Figures 5-2 and 5-3. |

The new unit(s) at the Grand Gulf ESP site would release liquid effluents mixed with the

GGNS Unit 1 radiological effluents and cooling tower blowdown to a discharge basin that is

then released into the Mississippi River. The liquid pathways considered are ingestion of

aquatic food, ingestion of drinking water, exposure to shoreline sediment, and external

exposure from the surface of contaminated water or from shoreline sediment and from

immersion in contaminated water (SERI 2005a). |

The gaseous pathways discussed in the SERI environmental report (SERI 2005a) were external |

exposure to the airborne radioactivity, external exposure to contaminated ground, inhalation of

airborne activity, and ingestion of contaminated agricultural products.

SERI (2005a) stated that the primary contribution to direct radiation exposure from new reactor |

designs would be from skyshine doses resulting from air scattering of high-energy gamma

radiation emitted by decaying nitrogen-16 in the reactor steam lines, turbines, and moisture

separators of the operating boiling water reactor. These doses were estimated and determined |

to be bounded by the doses produced from GGNS Unit 1 (SERI 2005a). |

5.9.2 Radiation Doses to Members of the Public

The dose to a maximally exposed individual was calculated from both the liquid and gaseous

effluent release pathways (SERI 2005a), and a collective whole body dose was calculated for |

the population within 80 km (50 mi) of the Grand Gulf ESP site.
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NUREG-1817 5-52 April 2006

Figure 5-2. Exposure Pathways to Humans
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April 2006 5-53 NUREG-1817

Figure 5-3. Exposure Pathways to Biota Other than Humans

|

5.9.2.1 Liquid Effluent Pathway

Liquid pathway doses were calculated by SERI using the LADTAP II computer program |

(Strenge et al. 1986) for the following activities: eating commercially caught fish and

invertebrates caught in the river and using the shoreline for recreational purposes. SERI’s |

environmental report (SERI 2005a) shows no use of the Mississippi River for drinking water |

within 160 km (100 mi) downstream from the Grand Gulf ESP site. Therefore, drinking water was

not calculated in the assessment. The liquid effluent releases for one ESP unit used in the |

estimate of dose to a maximally exposed individual are given in Table 3.0-8 of the SERI

environment report (SERI 2005a). These releases were based on a composite release that |

bounds the potential release from two Advanced Boiling Water Reactor (ABWR) units, two |

surrogate Advanced Pressurized Water Reactor (AP1000) units, and four Advanced CANDU |

(CANada Deuterium Uranium) Reactor ACR-700 units. Annual average liquid releases for each |

of these designs were compared. The most limiting isotopic releases were identified and then |

included in the composite release (SERI 2005b). This resulted in a slight increase in release |

rate for those isotopes where the ABWR design was the bounding condition. Other parameters
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NUREG-1817 5-54 April 2006

used as input to the LADTAP II program including effluent discharge rate, amount of

commercial fish catch, invertebrate harvest, and usage consumption factors are found in

| Tables 5.4-1 and 5.4-2 of the SERI environment report (SERI 2005a).

Liquid pathway doses to the maximally exposed individuals calculated by SERI are presented in

Table 5-5. The maximum annual dose to the total body of an adult was 0.022 mSv (2.2 mrem)

for one unit. The maximum annual dose to the bone of a child was 0.041 mSv (4.1 mrem)

| (SERI 2005a). The staff performed an independent evaluation of liquid pathway doses and

found similar results.

Table 5-5. Liquid Pathway Doses for Maximally Exposed Individual at the Grand Gulf Early

Site Permit Site from Operation of One New Nuclear Unit

Pathway

Total Body Dose (adult)

(mSv/yr)(a)

Maximum Organ (bone, child)

(mSv/yr)(a)

Aquatic Foods 0.022 0.041

Shoreline Use 3.1 x 10-5 | 3.6 x 10-5

Total 0.022 0.041

(a) Multiply mSv/yr by 100 to obtain mrem/yr.

| Source: SERI 2005a. Doses were estimated for one unit.

5.9.2.2 Gaseous Effluent Pathway

Gaseous pathway doses to the maximally exposed individual were calculated by SERI using the

GASPAR II computer program (Strenge et al. 1987) at the following locations: the nearest site

boundary, nearest vegetable garden, nearest residence, nearest milk cow, and nearest meat

cow. The gaseous effluents used in the estimate of dose to the maximally exposed individual

| are given in Table 3.0-7 of the SERI environmental report (SERI 2005a). These releases,

| which were estimated for one ESP unit, were based on a composite of the releases for each

| evaluated design type. The designs include two ABWR units, two surrogate AP1000 units,

| eight Gas Turbine Modular Helium Reactor (GT-MHR) modules, four ACR-700 units, and six

| International Reactor Innovative and Secure (IRIS) units. For each radionuclide, the highest

| release for any proposed design was used for the source term. Other parameters used as

input to the GASPAR II program (including milk, meat, and vegetable production rates,

meteorological data, population data, and consumption factors) are found in Tables 5.4-3

| through 5.4-7 of the SERI environmental report (SERI 2005a).

Gaseous pathway doses to the maximally exposed individuals calculated by SERI are

presented in Table 5-6. The dose calculations in Table 5-6 are based on dispersion factors

| from meteorological data from 2002 to 2003. The staff performed an independent evaluation of

gaseous pathway doses and found similar results.
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April 2006 5-55 NUREG-1817

5.9.3 Impacts on Members of the Public

The staff evaluated the impacts on members of the public from the operation of the proposed

Grand Gulf ESP facility by identifying the maximally exposed individual and population dose.

5.9.3.1 Maximally Exposed Individual

SERI (2005a) stated that whole body and organ dose estimates to the maximally exposed |

individual from liquid effluent and gaseous emissions for one unit were within the design

objectives of 10 CFR Part 50, Appendix I. The design objectives of 10 CFR Part 50, Appendix I |

are applicable to each reactor unit. Doses to whole body and maximum organ (bone) from |

liquid effluent were well within the 0.03 mSv/yr (3 mrem/yr) and 0.1 mSv/yr (10 mrem/yr)

10 CFR Part 50, Appendix I design objectives, respectively. Doses at the exclusion area |

boundary from gaseous effluents were well within the 10 CFR Part 50, Appendix I design |

objectives of 0.1 mGy/yr (10 mrad/yr) gamma in air, 0.2 mGy/yr (20 mrad/yr) beta in air,

0.05 mSv/yr (5 mrem/yr) dose to the whole body, and 0.15 mSv/yr (15 mrem/yr) dose to the

skin. In addition, dose to the thyroid was within the 0.15 mSv/yr (15 mrem/yr) 10 CFR Part 50, |

Appendix I design objectives (SERI 2005a). A comparison of dose estimates for one ESP unit |

to the 10 CFR Part 50, Appendix I design objectives is presented in Table 5-7. |

SERI (2005a) stated that doses from liquid and gaseous effluents to the maximally exposed |

individual at the site boundary from the existing GGNS Unit 1 and the proposed new nuclear |

unit or units combined were within the regulatory standards of 40 CFR Part 190. The dose |

standards from 40 CFR Part 190 are 0.25 mSv/yr (25 mrem/yr) to the whole body, 0.75 mSv/yr

(75 mrem/yr) to the thyroid, and 0.25 mSv/yr (25 mrem/yr) to any other organ. The combined

doses from the existing unit and the ESP units were 0.089 mSv/yr (8.9 mrem/yr) to the whole |

body, 0.17 mSv/yr (17 mrem/yr) to the thyroid, and 0.21 mSv/yr (21 mrem/yr) to the bone for |

the maximally exposed member of the public (SERI 2005a, Table 5.4-18). These data are |

summarized in Table 5-8. Therefore, the combined dose to the maximally exposed individual

from GGNS and the new units would be within the 40 CFR Part 190 standards, 10 CFR Part 20

standards, and 10 CFR Part 50, Appendix I design objectives. |

5.9.3.2 Population Dose

SERI (2005a) estimated a collective whole body dose within 80 km (50 mi) of each Grand Gulf |

ESP unit to be 0.032 person-Sv/yr (3.2 person-rem/yr). Collective dose was estimated using |

the LADTAP II and GASPAR II computer codes (SERI 2005a, Tables 5.4-10 and 5.4-13,

respectively). Collective dose from the liquid effluent pathways was calculated for the aquatic |

food pathway, but not drinking water since the Mississippi River is not used for drinking water |

within 160 km (100 mi). The staff independently evaluated the population doses and found 
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NUREG-1817 5-56 April 2006

Table 5-6. Gaseous Pathway Doses for Maximally Exposed Individual from Operation of

One New Nuclear Unit(a)

Dose Rate (mSv/yr)(b)

| Location Pathway Total Body Skin(c) Thyroid

Nearest Residence(d) |

(NNE, 1.02 km (0.64 mi))

|

| Plume Exposure 0.0063 0.021 0.0063

Inhalation

| Adult 0.0017 0.0069

| Teen 0.0017 0.0085

| Child 0.0015 0.0099

| Infant 0.00088 0.0086

Nearest Garden

(d) |

| (ENE, 1.01 km (0.63 mi))

Vegetable Consumption

| Adult 0.0039 0.029

| Teen 0.0049 0.036

| Child 0.009 0.067

Nearest Site Boundary(e) |

| (N, 0.93 km (0.58 mi))

|

| Plume Exposure 0.012 0.039 0.012

Inhalation

| Adult 0.0032 0.013

| Teen 0.0032 0.016

| Child 0.0028 0.018

Nearest Milk Cow(d) |

| (SSW, 16 km (10 mi))

|

|

Cow Milk

| Adult 0.000056 0.00055

| Teen 0.000083 0.00086

| Child 0.00016 0.0017

| Infant 0.00029 0.0041

Nearest Meat Cow(d) |

| (S, 6.4 km (4.0 mi))

Meat Consumption

| Adult 0.000065 0.00014

| Teen 0.000047 0.0001

| Child 0.000076 0.00016

| (a) Data provided in SERI 2005a was for one unit.

| (b) mSv = millisievert; multiply mSv/yr by 100 to obtain mrem/yr.

| (c) Skin dose is only applicable to plume exposure.

| (d) “Nearest” refers to the location at which the highest radiation dose to an individual from the applicable

| pathways has been estimated.

| (e) “Nearest” refers to that site boundary location at which the highest radiation doses from gaseous emissions

| have been estimated to occur.
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Table 5-7. Comparison of Maximum Individual Dose to 10 CFR Part 50, Appendix I

Design Objective per Unit |

Type of Dose Design Objective(a) Point of Evaluation Calculated Dose |

(a) |

Gaseous Effluents |

Gam ma air dose 0.1 mGy/yr |

(10 mrad/yr)

Exclusion Area Boundary 0.018 mGy/yr

(1.8 mrad/yr)

Beta air dose 0.2 mGy/yr |

(20 mrad/yr)

Exclusion Area Boundary 0.035 mGy/yr

(3.5 mrad/yr)

Total body dose 0.05 m Sv/yr |

(5 mrem/yr)

Exclusion Area Boundary 0.016 mSv/yr

(1.6 mrem/yr)

Skin dose 0.15 m Sv/yr |

(15 mrem/yr)

Exclusion Area Boundary 0.044 mSv/yr

(4.4 mrem/yr)

Radioiodines and Particulates

Vegetable |

Consumption

0.15 m Sv/yr

(15 mrem/yr)

Nearest Garden 0.067 mSv/yr

(6.7 mrem/yr)

(thyroid, child)

(a) mGy = milligray, mrad = millirad, mSv = millisievert, mrem = millirem |

Sources: 10 CFR Part 50, Appendix I; SERI 2005a |

Table 5-8. Comparison of Maximally Exposed Individual Dose Estimates from Liquid and

Gaseous Effluents from Operation of GGNS Unit 1 and Two New Nuclear Units to

40 CFR Part 190 Standards

Dose SERI Estimate |

(a)(b) 40 CFR Part 190 Standards(b) |

W hole body dose equivalent 0.089 mSv/yr 0.25 m Sv/yr |

Thyroid dose 0.17 m Sv/yr 0.75 m Sv/yr |

Dose to organ (bone) 0.21 m Sv/yr 0.25 m Sv/yr |

(a) Doses were estimated for GGNS Unit 1 and two ESP units (SERI 2005a, Table 5.4-18). |

(b) mSv = millisievert; multiply mSv/yr by 100 to obtain mrem/yr.

similar results. For comparative purposes, the estimated collective dose from natural |

background radiation to the population within 80 km (50 mi) of the proposed Grand Gulf ESP

site is 1020 person-Sv/yr (102,000 person-rem/yr). 

Although radiation may cause cancers at high doses and high dose rates, currently there are no

data that unequivocally establish the occurrence of cancer following exposure to low doses |
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NUREG-1817 5-58 April 2006

| below about 100 mSv (10,000 mrem) and at low dose rates. However, radiation protection

experts conservatively assume that any amount of radiation may pose some risk of causing

cancer or a severe hereditary effect and that the risk is higher for higher radiation exposures. 

Therefore, a linear, no-threshold dose response relationship is used to describe the relationship

| between radiation dose and detriments such as cancer induction. A recent report by the

| National Research Council (2006), BEIR VII report, supports the linear, no threshold dose

| response. Simply put, this theory states that any increase in dose, no matter how small, results

in an incremental increase in health risk. This theory is accepted by the NRC as a conservative

model for estimating health risks from radiation exposure, recognizing that the model probably

overestimates those risks.

Based on this model, the staff estimated the risk to the public from radiation exposure using the

nominal probability coefficient for total detriment (730 fatal cancers, nonfatal cancers, and

severe hereditary effects per 10,000 person-Sv (1,000,000 person-rem)) from International

| Commission on Radiological Protection (ICRP) Publication 60 (ICRP 1991). This coefficient

| was multiplied by the estimated collective whole body population dose of 0.032 person-Sv/yr

| (3.2 person-rem/yr) to calculate that the population living within 80 km (50 mi) of the Grand Gulf

| ESP site would incur a total of approximately 0.002 fatal cancers, nonfatal cancers, and severe

hereditary effects annually. The risks from the cumulative radiation exposure from GGNS and

the proposed ESP units would be only slightly higher. This risk is very small compared to the

estimated 75 fatal cancers, nonfatal cancers, and severe hereditary effects that the same

population would incur annually from exposure to natural sources of radiation.

| In addition, at the request of the U.S. Congress, the National Cancer Institute conducted a

| study and published “Cancer in Populations Living Near Nuclear Facilities” in 1990. This report

included an evaluation of health statistics around all nuclear power plants, as well as several

other nuclear fuel cycle facilities, in operation in the United States in 1981 and found “no

evidence that an excess occurrence of cancer has resulted from living near nuclear facilities”

(NCI 1990).

5.9.3.3 Summary of Radiological Impacts on Members of the Public

The NRC staff evaluated the health impacts from routine gaseous and liquid radiological

effluent releases from new nuclear units at the Grand Gulf ESP site. Based on the information

| provided by SERI and the NRC staff’s independent review, the NRC staff concludes there

| would be no observable health impacts on the public from normal operation of new nuclear

units, and the health impacts would be SMALL.

5.9.4 Occupational Doses to Workers

On the basis of information contained in NUREG-0713 (NRC 2002b), the average annual

| collective dose per operating reactor was 1.72 person-Sv/yr (172 person-rem yr) for the time
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April 2006 5-59 NUREG-1817

period from 1992 to 2001. Limited information is available on occupational dose estimates from

the advanced reactor designs, and SERI did not provide such information. However, Dominion

Energy, Inc., in a study regarding potential sites for new nuclear power plants, reported annual

occupational dose estimates of 1.5 person-Sv (150 person-rem) for the AP1000 reactor, IRIS,

and GT-MHR designs (Dominion and Bechtel 2002). The estimated occupational doses for the |

advanced reactor designs were slightly less than annual occupational doses for current light

water reactors (LWRs). The staff reviewed this information and concluded (1) that the |

information was generically applicable to SERI’s application and (2) that the annual dose |

estimates are reasonable. Moreover, the environmental impact from this occupational dose is

considered small because the dose to any individual worker is maintained within the limits of

10 CFR Part 20 (0.05 Sv/yr (5 rem/yr)). 

5.9.5 Impacts on Biota Other than Members of the Public

SERI (2005a) estimated doses to surrogate species (fish, invertebrates, algae, muskrat, |

raccoon, heron, and duck). Fish, invertebrates, and algae are referred to as aquatic species. 

Muskrats, racoons, herons, and ducks are referred to as terrestrial species. Important biota

species for the Grand Gulf ESP site and the corresponding surrogate species are bald eagle

and woodstork (heron), pallid sturgeon (fish), and fat pocketbook mussel (invertebrate). 

Surrogate species are well defined and provide an acceptable method for judging doses to the

biota (SERI 2005a). Exposure pathways considered in evaluating dose to the biota are |

discussed in Section 5.9.1 and shown in Figure 5-3.

5.9.5.1 Liquid Effluent Pathways

SERI (2005a) used the LADTAP II computer code to calculate doses to the biota from liquid |

effluent pathways. The following exposure pathways (illustrated in Figure 5-3) were evaluated |

for the different surrogate biota:

 C Fish and invertebrates – internal exposure from bioaccumulation of radionuclides and

external exposure from swimming and shoreline activities

 C Algae – internal exposure from bioaccumulation of radionuclides and external exposure

from immersion in water

 C Muskrat and duck – internal exposure from ingestion of aquatic plants and external

exposure from swimming and shoreline activities

 C Raccoon – internal exposure from ingestion of invertebrates and external exposure from

shoreline activities
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 C Heron – internal exposure from ingestion of fish and external exposure from swimming

and shoreline activities.

Input parameters used in the dose calculation included food consumption rates, body masses,

and effective body radii. These parameters were taken from NUREG/CR-4013

| (Strenge et al. 1986). These parameters are shown in Tables 5.4-14 and 5.4-15 of the SERI

| environmental report (SERI 2005a). The LADTAP II program has an adjustment factor

because the biota would be closer to any potential shoreline contamination than humans.

5.9.5.2 Gaseous Effluent Pathways

SERI used the doses calculated for the maximally exposed individual from the gaseous effluent

pathways (described earlier in this section) as a basis for the doses to the biota. External

doses from ground deposition were increased to account for the terrestrial organisms being

| closer to the ground (SERI 2005a).

5.9.5.3 Impacts of Estimated Biota Doses

| Table 5-9 compares the estimated whole body dose to the biota from the liquid and gaseous

| effluent pathways calculated by SERI (2005a) from one proposed new unit at the Grand Gulf

| ESP site to the regulatory standard for humans in 40 CFR Part 190. The biota doses for all

| surrogate species exceed the regulatory standard in 40 CFR Part 190 of 0.25 mSv/yr

| (25 mrem/yr) to the total body. This assumes mrem and mrad are approximately equivalent. 

| The staff performed an independent evaluation of biota doses and found similar results.

| The ICRP (1977, 1991) states that if man is adequately protected, then other living things are

| also likely to be sufficiently protected. The International Atomic Energy Agency (IAEA 1992)

| and the National Council on Radiation Protection and Measurements (NCRP 1991) reported

| that a chronic dose rate of no greater than 10 mGy/day (1 rad/day) to the maximally exposed

| individual in a population of aquatic organisms would ensure protection for the population. 

| IAEA (1992) also concluded that chronic dose rates of 1 mG/day (0.1 rad/day) or less do not

| appear to cause observable changes in terrestrial animal populations. Table 5-9 compares the

| estimated whole body dose to the biota for the proposed unit or units to the IAEA chronic dose

| rate values for aquatic organisms and terrestrial animals. The cumulative effects of current

| operating units and proposed unit or units would result in dose rates significantly less than the

NCRP and IAEA studies.

The staff performed an independent evaluation of doses to biota and found similar results. 
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April 2006 5-61 NUREG-1817

Table 5-9. Comparison of Biota Dose Estimates from Liquid and Gaseous Effluents from

Operation of New Nuclear Units to 40 CFR Part 190 Standards and Relevant |

Guidelines for Biota Protection

Biota |

Dose from Liquid

Effluents/Unit

(mGy/yr)(a)

Dose from

Gaseous

Effluents/Unit

(mGy/yr)(a)

Total

Dose/Unit

(mGy/yr)(a)

Total Dose

for Two

Units

(mGy/yr)(a)

40 CFR Part |

190 Total |

Body Dose

Limit

(mSv/yr)(b)

IAEA/NCRP |

Guideline for |

Protection of

Biota

Populations

(mGy/yr)(a)

Fish 0.25 0 0.25 0.51 0.25 3650

Invertebrate 1.65 0 1.65 3.31 0.25 3650

Algae 1.48 0 1.48 2.96 0.25 3650

Muskrat 0.81 0.022 0.83 1.67 0.25 365 |

Raccoon 0.19 0.02 0.21 0.42 0.25 365 |

Heron 1.93 0.018 1.95 3.91 0.25 365 |

Duck 0.81 0.023 0.83 1.67 0.25 365 |

(a) mGy = milligray; multiply mGy/yr by 100 to obtain mrad/yr. |

(b) mSv = millisievert; multiply mSv/yr by 100 to obtain mrem/yr. |

IAEA = International Atomic Energy Agency

NCRP = National Council on Radiation Protection and Measurements

Sources: SERI 2005a, Tables 5.4-16 and 5.4-17; IAEA 1992; NCRP 1991 |

|

In conclusion, the staff reviewed the available information related to the radiological impact on |

biota from the routine operation of the proposed Grand Gulf ESP unit(s) and concluded that the |

impact would be SMALL, and mitigation would not be warranted.

5.9.6 Radiological Monitoring

A radiological environmental monitoring program (REMP) (10 CFR 50.34a(a);

10 CFR 50.36a(a); SEC IV, B.2 of Appendix I in 10 CFR Part 50) has been performed around

the Grand Gulf site since 1978. The REMP includes monitoring of the airborne exposure

pathway, direct exposure pathway, water exposure pathway, aquatic exposure pathway with

control and indicator locations within a 29 km (18 mi) radius of the site. Milk is sampled when

there is commercial milk production within 8 km (5 mi) of the site. The pre-operational REMP

sampled various media in the environment to determine a baseline from which to observe the

magnitude and fluctuation of radioactivity in the environment once the unit began operation

(Entergy 2003b). The pre-operational program included collection and analysis of samples of

air particulates, precipitation, milk, crops, soil, well water, surface water, fish, and silt as well as

measurement of ambient gamma radiation. After operation of GGNS Unit 1 plant began

in 1985, the monitoring program continued to assess the radiological impacts on workers, the |

public, and the environment. Radiological releases are summarized in the two annual reports: 

the Annual Radiological Environmental Operating Report (Entergy 2003b) and Annual |

Radioactive Effluent Release Report (Entergy 2003a). The limits for all radiological releases
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NUREG-1817 5-62 April 2006

| are specified in the Grand Gulf Offsite Dose Calculation Manual (Entergy 2004). No additional

monitoring program has been established for the new unit(s). The staff reviewed the

| documentation for the REMP, the Grand Gulf Offsite Dose Calculation Manual, and recent

| monitoring reports from SERI and the state of Mississippi (MDH 2004) and determined that the

current operational monitoring program is adequate to establish the radiological baseline for

| comparison with the expected impacts on the environment related to the construction and

operation of proposed new unit(s) at the Grand Gulf ESP site.

5.10 Environmental Impacts of Postulated Accidents

The staff considered the radiological consequences on the human environment of potential

| accidents at one or more new nuclear units at the Grand Gulf ESP site. Consequence

estimates are based on the General Electric ABWR standard reactor design, which has been

| certified by the NRC (10 CFR Part 52, Appendix A), and the surrogate Westinghouse AP1000. 

The term “accident,” as used in this section, refers to any off-normal event not addressed in

Section 5.9 that results in the release of radioactive materials into the environment. The focus

of this review is on events that could lead to releases substantially in excess of permissible

limits for normal operations. Normal release limits are specified in 10 CFR Part 20, Appendix B,

Table 2.

Numerous features combine to reduce the risk associated with accidents at nuclear power

plants. Safety features in the design, construction, and operation of the plants, which compose

the first line of defense, are intended to prevent the release of radioactive materials from the

plant. The design objectives and the measures for keeping levels of radioactive materials in

| effluents to unrestricted areas as low as is reasonably achievable (ALARA) are specified in

10 CFR Part 50, Appendix I. There are additional measures that are designed to mitigate the

consequences of failures in the first line of defense. These include the NRC’s reactor site

criteria in 10 CFR Part 100, which require the site to have certain characteristics that reduce the

risk to the public and the potential impact of an accident, and emergency preparedness plans

and protective action measures for the site and environs as set forth in 10 CFR 50.47;

| 10 CFR Part 50, Appendix E; and NUREG-0654/FEMA-REP-1 (NRC and FEMA 1980). All of

these safety features, measures, and plans make up the defense-in-depth philosophy to protect

the health and safety of the public and the environment.

This section discusses (1) the types of radioactive materials, (2) the paths to the environment,

(3) the relationship between radiation dose and health effects, and (4) the environmental

| impacts of postulated reactor accidents, both design basis accidents (DBAs) and severe

accidents. The environmental impacts of postulated accidents during transportation of spent

fuel are discussed in Chapter 6.
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April 2006 5-63 NUREG-1817

The potential for dispersion of radioactive materials in the environment depends on the

mechanical forces that physically transport the materials and on the physical and chemical |

forms of the materials. Radioactive material exists in a variety of physical and chemical forms. 

The majority of the material in the fuel is in the form of nonvolatile solids. However, there is a

significant amount of material that is in the form of volatile solids or gases. Gaseous

radioactive materials include the chemically inert noble gases krypton and xenon, which have a

high potential for release. Radioactive forms of iodine, which are created in substantial

quantities in the fuel by fission, are volatile. Other radioactive materials formed during the

routine operation of a nuclear power plant have lower volatilities and, therefore, have lower

tendencies to escape from the fuel than the noble gases and iodines.

Radiation exposure to individuals is determined by their proximity to radioactive material, the

duration of their exposure, and the extent to which they are shielded from the radiation. 

Pathways that lead to radiation exposure include external radiation from radioactive material in

the air, on the ground, and in the water; the inhalation of radioactive material; and ingestion of

food or water containing material initially deposited on the ground and in water.

The risks of health effects from radiation exposure below 0.1 Sv (10 rem) are either too small to |

be observed or are non-existent (HPS 2004). After exposure to higher levels of radiation, |

incidences of cancer in the exposed general population may begin to develop after a lapse of |

2 to 15 years (latent period) and then level off over a period of about 30 years (plateau period). |

In the case of radiation exposure of fetuses, cancer may begin to develop as early as at birth

(no latent period) to the age of 10.

Physiological effects are clinically detectable should individuals receive radiation exposure

resulting in a dose greater than about 0.25 Sv (25 rem) over a short period of time (hours). 

Doses of about 2.5 to 5.0 Sv (250 to 500 rem) received over a relatively short period (hours to a

few days) can be expected to cause some fatalities.

5.10.1 Design Basis Accidents

SERI evaluated the potential consequences of postulated accidents to demonstrate that new

unit(s) could be constructed and operated at the Grand Gulf ESP site without undue risk to the |

health and safety of the public. These evaluations use a set of surrogate DBAs that are

representative for the range of reactor designs being considered for the ESP site and sitespecific meteorological data. The set of accidents covers events that range from relatively high

probability of occurrence with relatively low consequences to relatively low probability with

high consequences.

The DBA review focuses on two light water reactor designs: the ABWR and the surrogate

AP1000. The bases for analyses of postulated accidents for these designs are well established

because they have been considered as part of the NRC’s advanced reactor design certification
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NUREG-1817 5-64 April 2006

| process. Accidents for the other reactor designs listed in SERI’s ESP are not as well defined as

those for the ABWR and the surrogate AP1000; acceptable assumptions and methodologies for

| the evaluation of postulated accidents have not been fully established. Consequently, design

| basis accidents for reactor designs other than light-water designs are not resolved. Because

the source terms for accident analyses are generally proportional to the power level, for the

purposes of this environmental impact evaluation, the potential consequences of accidents for

the other reactor designs are expected to be bounded by those for the ABWR and surrogate

AP1000 designs. For example, preliminary information on source terms for the IRIS and ACR700 reactor designs indicates that the source terms for the surrogate AP1000 loss-of-coolant

accident (LOCA) would bound the worst-case accident release for these advanced reactor

designs. Similarly, the ABWR source terms are expected to bound the source terms for the

Economic Simplified Boiling Water Reactor (ESBWR) design. The advanced gas reactor

| designs (GT-MHR and Pebble Bed Modular Reactor) postulate relatively small releases to the

| environment compared to water reactor technologies (SERI 2005a).

| Should an application for a CP or COL that references an ESP at the Grand Gulf ESP site

| reference one of the designs other than an ABWR or surrogate AP1000, the applicant would be

required to show – and the staff would verify – that the radiological consequences of DBAs for

| the proposed reactor(s) are bounded by the consequences of DBAs evaluated in this EIS.

Potential consequences of DBAs are evaluated following procedures outlined in regulatory

guides and standard review plans. The potential consequences of accidental releases depend

on the specific radionuclides released, the amount of each radionuclide released, and

meteorological conditions. The source terms for the ABWR design are based on TID-14844

(AEC 1962) guidance, and guidance on methods for evaluating potential accidents for the

ABWR are set forth in NUREG-0800 (NRC 1987), Regulatory Guide 1.3 (NRC 1974a), and

Regulatory Guide 1.25 (NRC 1974b). The source terms for the surrogate AP1000 reactor and

methods for evaluating potential accidents are based on guidance in Regulatory Guide 1.183

(NRC 2000b).

For environmental reviews, consequences are evaluated assuming realistic meteorological

conditions. Meteorological conditions are represented in these consequence analyses by an

atmospheric dispersion factor, which is also referred to as X/Q. Acceptable methods of

calculating X/Q for DBAs from meteorological data are set forth in Regulatory Guide 1.145

(NRC 1983).

SERI provided the staff with meteorological data for the Grand Gulf ESP site for 2002 and 2003

| (SERI 2004b). These data have been reviewed by the staff and found to be representative of

the meteorological conditions at the site. The meteorological instrumentation and its

maintenance are consistent with staff guidance, and the data quality is consistent with
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April 2006 5-65 NUREG-1817

standards set forth in that guidance. Therefore, the data are considered acceptable for use in

evaluation of the consequences of DBAs. The staff also reviewed SERI’s procedures for

calculating site-specific X/Qs and found them to be consistent with staff guidance.

Table 5-10 lists X/Q values pertinent to the evaluation of the suitability of the Grand Gulf ESP

site. The first column lists the time periods and boundaries for which X/Q values and dose

estimates are needed. For the EAB, the postulated DBA dose and its atmospheric dispersion |

factor are calculated for a short-term, i.e., 2 hours, and for the low population zone (LPZ), they

are calculated for the course of the accident, i.e., 30 days (720 hours) composed of four time

periods. The second column lists the X/Q values calculated by SERI using the site

meteorological information discussed in environmental report Section 2.7.5 (SERI 2005a) and |

the EAB and LPZ distances from Section 2.7.6 of the environmental report. No credit was |

taken for building wake. These X/Q values are expected to be exceeded no more than five |

percent of the time.

Table 5-10. Atmospheric Dispersion Factors (X/Q, s/m3) for the Grand Gulf Early Site Permit

Site Design Basis Accident Calculations

Time Period(a) and Boundary

Site

Adverse Typical

0 to 2 hr, Exclusion Area Boundary 5.95 x 10-4 8.82 x 10-5

0 to 8 hr, Low Population Zone 8.83 x 10-5 2.83 x 10-5

8 to 24 hr, Low Population Zone 6.16 x 10-5 2.21 x 10-5

1 to 4 day, Low Population Zone 2.82 x 10-5 1.29 x 10-5

4 to 30 day, Low Population Zone 9.15 x 10-6 5.95 x 10-6

(a) Times are relative to the beginning of the release to the environment.

In its independent assessment, the staff evaluated SERI’s process for deriving the site X/Q

values from site-specific information. The staff determined the process is consistent with NRC

guidance (NRC 1983), but the X/Q values are not acceptable for use in environmental reviews

because they are for adverse meteorological conditions rather than typical conditions.

Using information provided by SERI and the procedure described in Regulatory Guide 1.145,

the staff estimated site X/Q values for typical meteorological conditions using the EAB and LPZ |

distances given in the ESP application. The staff’s estimates of X/Q values for typical

meteorological conditions are listed in the last column of Table 5-10. These values indicate the

atmospheric dilution capability in the vicinity of the site. Small X/Q values are associated with

greater dilution capability. Thus, if a design X/Q value for a specific reactor design identified as

part of the CP or COL were greater than or equal to the site-specific X/Q value, then

atmospheric dispersion at the site is sufficient such that the doses predicted for postulated

DBAs for the design would likely be below regulatory limits.
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NUREG-1817 5-66 April 2006

The staff concludes that the atmospheric dispersion characteristics of the Grand Gulf ESP site

are acceptable with respect to the potential environmental consequences of postulated DBAs

| for reactor designs with design X/Q values falling within the bounds set by the staff’s site X/Q

| values. At the CP or COL stage, the staff would need to verify that the X/Q values for reactor

| designs proposed at the CP/COL stage are bounded by the site X/Q values used in this

| analysis. Additional evaluation will be needed if reactor design X/Q values do not meet this

| criterion.

Tables 5-11 and 5-12 list the set of surrogate DBAs considered by SERI and present the staff’s

estimate of the environmental consequences of each DBA in terms of total effective dose

equivalent (TEDE). TEDE is the sum of the committed effective dose equivalent (CEDE) from

inhalation and the deep dose equivalent from external exposure. Dose conversion factors from

Federal Guidance Report 11 (Eckerman et al. 1988) were used to calculate the CEDE. 

Similarly, dose conversion factors from Federal Guidance Report 12 (Eckerman and

Ryman 1993) were used to calculate the deep dose equivalent. 

| TEDE values were estimated for the ABWR by multiplying the thyroid dose by a factor of 0.03

(the organ weighting factor for the thyroid in the TEDE methodology) and adding the product to

the whole body dose. The review criteria used in the staff’s safety review of DBA doses are

included in Tables 5-11 and 5-12 to illustrate how small the calculated environmental

consequences (TEDE doses) are.

In addition to the evaluation of the DBAs for the ABWR and surrogate AP1000 designs

described above, SERI evaluated the consequences of a postulated LOCA for the ACR-700

reactor design. The staff’s estimate of the 0 to 2 hr TEDE at the EAB is 8.8 x 10-3 | Sv

(0.88 rem), and the estimate for TEDE for the LPZ is 1.7 x 10-2 Sv (1.7 rem). These TEDE

values for the ACR-700 are well below the review criteria used in the staff’s safety review of

| DBA doses (0.25 Sv (25 rem) for EAB and LPZ). These comparisons are included to illustrate

how small the calculated environmental consequences (TEDE doses) are.

| In all cases, the calculated TEDE values are small – considerably smaller that the TEDE doses

used as safety review criteria. The environmental impacts of DBAs have not been explicitly

| evaluated for gas-cooled reactors because necessary design information is lacking. The staff

| expects, however, that releases to the environment under accident conditions would be small 

| for such designs. Should an applicant for a CP or COL reference an LWR design, the staff 

| would need to verify that the doses for postulated DBAs for the actual reactor design remain

bounded by the environmental impacts from the surrogate reactor designs considered in this

| EIS. Because impacts of DBAs for gas-cooled designs are not resolved at the ESP stage, the

| applicant would need to provide an evaluation of the impacts of DBAs. 
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April 2006 5-67 NUREG-1817

Table 5-11. Design Basis Accident Doses for an Advanced Boiling Water Reactor

TEDE in Sv(a)

Accident

Standard

Review Plan

Section(b) EAB LPZ

Review

Criterion

Main Steam Line Break 15.6.4

 Pre-Existing Iodine Spike 1.4 x 10-3 4.8 x 10-4 2.5 x 10-1(c)

 Accident-Initiated Iodine Spike 7.0 x 10-5 2.4 x 10-5 2.5 x 10-2(d)

Loss-of-Coolant Accident 15.6.5 5.9 x 10-3 5.4 x 10-2 2.5 x 10-1(c)

Failure of Small Lines Carrying

Primary Coolant Outside

Containment

15.6.2 1.2 x 10-4 4.2 x 10-5 2.5 x 10-2(d)

Fuel Handling 15.7.4 9.8 x 10-4 3.3 x 10-4 6.25 x 10-2(d)

(a) To convert Sv to rem, multiply by 100. |

(b) NUREG-0800 (NRC 1987)

(c) 10 CFR 50.34(a)(1); 10 CFR 100.11; 10 CFR 100.21 |

(d) Standard Review Plan criterion

EAB = exclusion area boundary |

LPZ = low population zone |

TEDE = total effective dose equivalent |

Although SERI chose to use the PPE approach in its ESP application, it based its evaluation of

the environmental impact of DBAs on characteristics of the ABWR and the surrogate AP1000

reactor designs with the explicit assumption that the impact would bound the impact of other

advanced LWR designs (SERI 2005a). The NRC staff reviewed the analysis in the |

environmental report, which is based on analyses performed for design certification of these

reactor designs and found it appropriate for safety analyses, but overly conservative for

environmental reviews. Therefore, the staff adjusted the results of the SERI analysis to reflect

typical meteorological conditions. The results of both the SERI and the staff analyses indicate

that the environmental risks associated with DBAs, should an advanced LWR be located at the |

Grand Gulf ESP site, would be small compared to the TEDE doses used as safety review

criteria. On this basis, the staff concludes that the consequences of DBAs at the Grand Gulf

ESP site are of SMALL significance for advanced LWRs. The environmental impacts of DBAs

have not been explicitly evaluated for gas-cooled reactors and are, therefore, unresolved. |

These impacts would need to be evaluated at the CP or COL stage if such a design were |

selected. For the evaluation in this EIS to bound the reactor design selected at the CP or COL |

stage, an applicant referencing the Grand Gulf ESP would need to demonstrate that the |

environmental impacts of a DBA at the proposed Grand Gulf ESP site remain bounded by the

environmental impacts for the surrogate designs considered in this EIS.
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NUREG-1817 5-68 April 2006

Table 5-12. Design Basis Accident Doses for a Surrogate AP1000 Reactor

TEDE in Sv(a)

Accident

Standard

Review Plan

Section(b) EAB LPZ

Review

Criterion

Main Steam Line Break 15.1.5

 Pre-Existing Iodine Spike 9.6 x 10-4 1.0 x 10-3 2.5 x 10-1(c)

 Accident-Initiated Iodine Spike 1.1 x 10-3 3.8 x 10-3 2.5 x 10-2(d)

Steam Generator Rupture 15.6.3

 Pre-Existing Iodine Spike 4.1 x 10-3 7.5 x 10-4 2.5 x 10-1(c)

 Accident-Initiated Iodine Spike 2.1 x 10-3 5.3 x 10-4 2.5 x 10-2(d)

Loss-of-Coolant Accident 15.6.5 3.4 x 10-2 2.2 x 10-2 2.5 x 10-1(c)

Rod Ejection 15.4.8 4.1 x 10-3 3.7 x 10-3 6.25 x 10-2(d)

Reactor Coolant Pum p Rotor Seizure

(Locked Rotor)

15.3.3 3.5 x 10-3 1.3 x 10-3 2.5 x 10-2(d)

Failure of Small Lines Carrying Primary

Coolant Outside Containment

15.6.2 1.8 x 10-3 6.4 x 10-4 2.5 x 10-2(d)

Fuel Handling 15.7.4 3.3 x 10-3 1.3 x 10-3 6.25 x 10-2(d)

| (a) To convert Sv to rem, multiply by 100. 

(b) NUREG-0800 (NRC 1987)

| (c) 10 CFR 50.34(a)(1); 10 CFR 100.21

(d) Standard Review Plan criterion

| EAB = exclusion area boundary

| LPZ = low population zone

| TEDE = total effective dose equivalent

5.10.2 Severe Accidents

| In its environmental report, SERI (2005a) bases its evaluation of the potential environmental

consequences of severe accidents on the evaluation of potential consequences of severe

accidents for current generation reactors presented in the GEIS (NRC 1996). Three pathways

were considered: the atmospheric pathway in which radioactive material is released to the air,

the surface water pathway in which airborne radioactive material falls out on open bodies of

water, and the groundwater pathway in which groundwater is contaminated by a basemat meltthrough with subsequent contamination of surface water by the groundwater.

In response to an NRC request for additional information dated May 19, 2004 (NRC 2004a),

SERI performed a site-specific analysis of the potential environmental consequences of

postulated severe accidents at the Grand Gulf ESP site. Because the PPE does not include

source terms for severe accidents, SERI used the source terms for the ABWR and surrogate

AP1000 reactors. SERI used the MACCS2 computer code (Chanin et al. 1990; Jow et al.
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April 2006 5-69 NUREG-1817

1990) for the analysis. Input to the MACCS2 computer code and summary results of the

analysis were submitted to the NRC in a letter dated August 10, 2004 (SERI 2004g). |

The MACCS computer code was developed to evaluate the potential offsite consequences of

severe accidents for the sites covered by NUREG-1150 (NRC 1990). MACCS2 (Chanin and

Young 1997) is the current version of MACCS. The MACCS and MACCS2 codes evaluate the

consequences of atmospheric releases of radioactive material following a severe accident. The

pathways modeled include external exposure to the passing plume, exposure to material

deposited on the ground and skin, inhalation of material in the passing plume and resuspended

from the ground, and ingestion of contaminated food and surface water. The primary

enhancements in MACCS2 are that MACCS2 has (1) a more flexible emergency response

model, (2) an expanded library of radionuclides, and (3) a semidynamic food-chain model

(Chanin and Young 1997).

Three types of severe accident consequences were assessed: (1) human health, (2) economic

costs, and (3) land area affected by contamination. Human-health effects are expressed in

terms of the number of cancers that might be expected if a severe accident were to occur. 

These effects are directly related to the cumulative radiation dose received by the general

population. MACCS2 estimates both early cancer fatalities and latent fatalities. Early fatalities

are related to high doses or dose rates and can be expected to occur within a year of exposure

(Jow et al. 1990). Latent fatalities are related to exposure of a large number of people to low

doses and dose rates and can be expected to occur after a latent period of several (2 to 15)

years. Population health-risk estimates (latent and early cancers) are based on the population

distribution within an 80-km (50-mi) radius of the plant, although early fatalities would be

expected only in the population near the site. MACCS2 also calculates average individual

health risks (early and latent fatalities) for individuals near the site. The risk of an early cancer

fatality is calculated for individuals within 1.6 km (1 mi) and the risk of a latent cancer fatality is

calculated for individuals within 16 km (10 mi). Economic costs of a severe accident include the

costs associated with short-term relocation of people, decontamination of property and

equipment, interdiction of food supplies, land and equipment use, and condemnation of

property. The affected land area is a measure of the areal extent of the residual contamination

following a severe accident.

Risk is the product of the frequency of an accident and the consequences of the accident. For

example, the probability of a severe accident without loss of containment for an ABWR is

estimated to be 1.34 x 10-7 per reactor year (Ryr-1); and the cumulative population dose

associated with a severe accident without loss of containment at the Grand Gulf ESP site is

calculated to be 7.11 x 101 person-Sv (7.11 x 103 person-rem). The population dose risk for

this class of accidents is the product of 1.34 x 10-7 Ryr-1 and 7.11 x 101 person-Sv, or 

9.53 x 10-6 person-Sv Ryr-1 (9.53 x 10-4 person-rem Ryr-1). The following sections discuss the

estimated risks associated with each pathway.
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NUREG-1817 5-70 April 2006

The risk presented in the tables that follow is risk per year of reactor operation. SERI has

indicated the Grand Gulf ESP site could support reactors producing a total of 8600 MW(t). 

Based on this limit, the site could hold two ABWR or AP1000 reactors. The consequences of a

severe accident would be the same regardless of whether one or two reactors were built. 

However, if two reactors were built, the risk would apply to each reactor, and the total risk for

new reactors at the site would be twice the risk for a single reactor. Even if the risk values were

doubled, the risks would still be significantly smaller than the risks associated with currentgeneration reactors.

5.10.2.1 Air Pathway

The MACCS2 code directly estimates consequences associated with releases to the air

pathway. For the purposes of this analysis, the power levels of the ABWR and surrogate

| AP1000 reactors were scaled to 4300 MW(t) and 3415 MW(t), respectively (SERI 2004g). The

results of the MACCS2 runs are presented in Tables 5-13 and 5-14. The core damage

frequencies given in these tables are for internally initiated accident sequences while the plant

is at power. Internally initiated accident sequences include sequences initiated by equipment

| failures, loss of offsite power, and human error. Based on insights from the review of the

advanced LWR probabilistic risk assessments, the core damage frequencies for externally

initiated events and during shutdown would be comparable to or lower than those for internally

initiated events.

Tables 5-13 and 5-14 show that the probability weighted consequences, i.e., the risks, of

severe accidents for an ABWR or a surrogate AP1000 reactor located on the Grand Gulf ESP

site are small for all risk categories considered. For perspective, Tables 5-15 and 5-16

compare the health risks from severe accidents for the ABWR or surrogate AP1000 reactors at

the Grand Gulf ESP site with the risks for current-generation reactors at various sites.

In Table 5-15, the health risks estimated for the ABWR and surrogate AP1000 reactors at the

Grand Gulf ESP site are compared with health risk estimates for the five reactors considered in

NUREG-1150 (NRC 1990). Although risks associated with both internally and externally

initiated events were considered for the Peach Bottom and Surry reactors in NUREG-1150, only

risks associated with internally initiated events are presented in Table 5-16. The health risks

shown for the ABWR and surrogate AP1000 reactors at the Grand Gulf ESP site are

| significantly lower than the risks associated with current-generation operating reactors

presented in NUREG-1150 (NRC 1990).

In addition, the last two columns of Table 5-15 provide average individual fatality risk estimates

for comparison to the Commission’s safety goals. The Commission has set safety goals for
NUREG-1817 5-71 April 2006

Table 5-13. Mean Environmental Risk from Advanced Boiling Water Reactor Severe Accidents at the G

Permit Site Environmental Risk Release Category Description (Accident Class) Core Damage Frequency (Ryr-1) Population Dose (person-Sv Ryr-1)(a) Fatalities (Ryr-1) Cost(d) ($ Ryr-1) Land Requirin

Decontaminatio

(ha Ryr-1) 

Early(b) Latent(c) 0 No loss of containment 1.34 x 10-7 9.53 x 10-6 0 4.12 x 10-7 3.05 x 10-2 1.10 x 10-6 

1 Transients followed by failure of high-pressure coolant makeup water and failure to depressurize in timely fashion 2.08 x 10-8 1.27 x 10-6 0 6.91 x 10-8 6.98 x 10-3 1.60 x 10-7 2 Short-term station blackout

with reactor core isolationcooling (RCIC) failure, onsitepower recovery in 8 hr

1.00 x 10-10 2.43 x 10-9 0 1.04 x 10-10 1.79 x 10-6 8.31 x 10-11 

3 Station blackout with RCIC

available for about 8 hr

1.00 x 10-10 1.86 x 10-7 0 8.61 x 10-9 1.02 x 10-2 5.79 x 10-7 

4 Station blackout (more than

8 hr) with RCIC failure

1.00 x 10-10 1.18 x 10-7 0 5.25 x 10-9 7.39 x 10-3 4.11 x 10-7 

5 Transients followed by

failure of high pressurecoolant makeup water,successful depressurization of reactor, failure of lowpressure coolant makeupwater

1.00 x 10-10 4.88 x 10-8 0 2.00 x 10-9 6.4 1x 10-3 1.12 x 10-7 
April 2006 5-72 NUREG-1817

Table 5-13. (contd)

Release Category Description

(Accident Class)

Core

Damage

Frequency

(Ryr-1)

Population Dose

(person-Sv Ryr-1)(a)

Fatalities (Ryr-1)

Cost(d)

($ Ryr-1)

Land Requirin

Decontaminatio

(ha Ryr-1)

Early(b) Latent(c)

6 Transient, loss-of-coolant

accident (LOCA), andanticipated transient withoutscram (ATWS) events withsuccessful coolant makeupwater, but potential priorfailure of containment

1.00 x 10-10 5.72 x 10-7 0 2.61 x 10-8 1.53 x 10-1 1.06 x 10-5 

7 Small/medium LOCA

followed by failure of highpressure coolant makeupwater and failure todepressurize

3.91 x 10-10 2.56 x 10-6 0 1.15 x 10-7 6.62 x 10-1 4.34 x 10-5 

| 8 LOCA followed by failure of

high-pressure coolantmakeup water

4.05 x 10-10 4.24 x 10-6 9.46 x 10-13 1.93 x 10-7 1.10 x 10+0 5.24 x 10-5 

|

9 ATWS followed by boron

injection failure andsuccessful high-pressurecoolant makeup water

1.70 x 10-10 2.29 x 10-6 5.91 x 10-14 1.13 x 10-7 5.15 x 10-1 2.18 x 10-5 

Total 1.56 x 10-7 2.08 x 10-5 1.00 x 10-12 9.45 x 10-7 2.49 x 10+0 1.31 x 10-4 (a) To convert person-Sv to person-rem, multiply by 100.(b) Early fatalities are fatalities related to high doses or dose rates that generally can be expected to occur within a year of the exp

(c) Latent fatalities are fatalities related to low doses or dose rates that could occur after a latent period of several (2 to 15) years.

(d) Cost risk includes costs associated with short-term relocation of people, decontamination, interdiction, and condemnation. It do

| associated with health effects (Jow et al. 1990). 

(e) Land risk is farm land requiring decontamination prior to resumption of agricultural usage. To convert hectares (ha) to acres, m
NUREG-1817 5-73 April 2006

Table 5-14. Mean Environmental Risk from the Surrogate AP1000 Severe Accidents at the Grand Gulf Earl

Environmental Risk Release Category Description (Accident Class) Core Damage Frequency (Ryr-1) Population Dose (person-Sv Ryr-1)(a) Fatalities (Ryr-1) Cost(d) ($ Ryr-1) Land Requiring Decontamination

(ha Ryr-1) 

Early(b) Latent(c) CFI Intermediate containment failure, after core relocation but before 24 hr 1.89 x 10-10 7.49 x 10-7 0 3.73 x 10-7 1.27 x 10-1 1.03 x 10-5 

CFE Early containment failure,

after onset of core damagebut before core relocation

7.47 x 10-9 3.07 x 10-5 0 1.46 x 10-6 5.81 x 10+0 3.75 x 10-4 

IC Intact containment 2.21 x 10-7 7.98 x 10-6 0 3.98 x 10-7 3.66 x 10-2 2.48 x 10-6 BP Containment bypass, fission

products released directly toenvironment 

1.05 x 10-8 9.91 x 10-5 0 4.72 x 10-6 1.93 x 10+1 1.08 x 10-3 

CI Containment isolation failure

occurs prior to onset of coredamage

1.33 x 10-9 4.90 x 10-6 0 2.63 x 10-7 8.66 x 10-1 5.51 x 10-5 

CFL Late containment failure

occurring after 24 hr

3.45 x 10-13 1.83 x 10-9 0 8.21 x 10-11 3.81 x 10-4 3.07 x 10-8 

Total 2.40 x 10-7 1.43 x 10-4 <1.00 x 10-12 6.87 x 10-6 2.61 x 10+1 1.53 x 10-3 (a) To convert person-Sv to person-rem, multiply by 100.(b) Early fatalities are fatalities related to high doses or dose rates that generally can be expected to occur within a year of the expo

(c) Latent fatalities are fatalities related to low doses or dose rates that could occur after a latent period of several (2 to 15) years.

(d) Cost risk includes costs associated with short-term relocation of people, decontamination, interdiction, and condemnation. It do

associated with health effects (Jow et al. 1990). 

(e) Land risk is farm land requiring decontamination prior to resumption of agricultural usage. To convert hectares (ha) to acres, m
April 2006 5-74 NUREG-1817

Table 5-15. Comparison of Environmental Risk for an Advanced Boiling Water Reactor or a Surrogate 

Grand Gulf Early Site Permit Site with Risk for Five Sites Evaluated in NUREG-1150

Reactor Site

Core Damage

Frequency

(Ryr-1)

50-mi (80-km)

Population Dose

Risk

(person-Sv Ryr-1)(a)

Fatalities (Ryr-1) Average Individual F

Early Latent Early L

Grand Gulf(b) 4.0 x 10-6 5 x 10-1 8 x 10-9 9 x 10-4 3 x 10-11 

Peach Bottom(b) 4.5 x 10-6 7 x 10+0 2 x 10-8 5 x 10-3 5 x 10-11 Sequoyah(b) 5.7 x 10-5 1 x 10+1 3 x 10-5 1 x 10-2 1 x 10-8 Surry(b) 4.0 x 10-5 5 x 10+0 2 x 10-6 5 x 10-3 2 x 10-8 Zion(b) 3.4 x 10-4 5 x 10+1 1 x 10-4 2 x 10-2 9 x 10-9 ABWR(c) 1.6 x 10-7 2 x 10-5 1 x 10-12 9 x 10-7 2 x 10-14 AP1000(c) 2.4 x 10-7 1 x 10-4 <1 x 10-12 7 x 10-6 < 1 X 10-14 | (a) To convert person-Sv to person-rem, multiply by 100.(b) Risks were calculated using the MACCS code and presented in NUREG-1150 (NRC 1990).(c) Calculated with MACCS2 code using Grand Gulf site-specific input.
Operation Impacts at the Proposed Site

April 2006 5-75 NUREG-1817

Table 5-16. Comparison of Environmental Risk from Severe Accidents Initiated by Internal

Events for an Advanced Boiling Water Reactor and a Surrogate AP1000 at the

Grand Gulf Early Site Permit Site with Risks for Current Reactors |

Reactor Site

Core Damage

Frequency

(yr-1)

50-mi (80-km) Population

Dose Risk

(person-Sv Ryr-1)

(a)

Current Reactor Maximum (b) 2.4 x 10-4 6.9 x 10-1

Current Reactor Mean(b) 3.6 x 10-5 1.5 x 10-1

Current Reactor Median(b) 2.8 x 10-5 1.4 x 10-1

Current Reactor Minimum(b) 1.9 x 10-6 5.5 x 10-3

ABW R

(c) 1.6 x 10-7 2.1 x 10-5

AP1000(c) 2.4 x 10-7 1.4 x 10-4

(a) To convert person-Sv to person-rem, multiply by 100.

(b) Based on MACCS and MACCS2 calculations for current plants undergoing operating

license renewal.

(c) Calculated with MACCS2 code using Grand Gulf site-specific input.

average individual early fatality and cancer fatality risks from reactor accidents in the safety

goal policy statement (51 FR 30028). The policy statement expressed the Commission’s policy |

regarding the acceptance level of radiological risk from nuclear power plant operation

as follows:

C Individual members of the public should be provided a level of protection from the

consequences of nuclear power plant operation such that individuals bear no significant

additional risk to life and health. 

C Societal risks to life and health from nuclear power plant operation should be comparable to

or less than the risks of generating electricity by viable competing technologies and should

not be a significant addition to other societal risks.

The following quantitative health objectives are used in determining achievement of the

safety goals:

C The risk to an average individual in the vicinity of a nuclear power plant of prompt fatalities

that might result from reactor accidents should not exceed one-tenth of 1 percent

(0.1 percent) of the sum of prompt fatality risks resulting from other accidents to which

members of the U.S. population are generally exposed.
Operation Impacts at the Proposed Site

NUREG-1817 5-76 April 2006

C The risk to the population in the area near a nuclear power plant of cancer fatalities that

might result from nuclear power plant operation should not exceed one-tenth of 1 percent

(0.1 percent) of the sum of cancer fatality risks resulting from all other causes.

These quantitative health objectives are translated into two numerical objectives as follows:

C The individual risk of a prompt fatality from all “other accidents to which members of the

U.S. population are generally exposed,” such as fatal automobile accidents, is about 5 x 10-4

| per year. One-tenth of one percent of this figure implies that the individual risk of prompt

fatality from a reactor accident should be less than 5 x 10-7 | per reactor year.

C “The sum of cancer fatality risks resulting from all other causes” for an individual is taken to

be the cancer fatality rate in the United States, which is about 1 in 500 or 2 x 10-3 | per year. 

One-tenth of 1 percent of this implies that the risk of cancer to the population in the area

near a nuclear power plant because of its operation should be limited to 2 x 10-6 | per

reactor year.

| MACCS2 calculates average individual early and latent cancer fatality risks. The average

individual early fatality risk is calculated using the population distribution within 1.6 km (1 mi) of

the plant boundary. The average individual latent cancer fatality risk is calculated using the

population distribution within 16 km (10 mi) of the plant. For the plants considered in

NUREG-1150, these risks were well below the Commission’s safety goals. Risks calculated for

the ABWR and surrogate AP1000 designs at the Grand Gulf ESP site are lower than the risks

| associated with the current-generation reactors considered in NUREG-1150, and are well below

the Commission’s safety goals.

The staff compared the core damage frequencies and population dose risk estimates for the

ABWR and surrogate AP1000 reactors at the Grand Gulf ESP site with statistics summarizing

| the results of contemporary severe accident analyses performed for 28 current-generation

operating reactors at 23 sites. The results of these analyses are included in the final sitespecific Supplements 1 through 20 to the GEIS (NRC 1996), and in the environmental reports

| included with license renewal applications for those plants for which supplements to the GEIS

have not been published. All of the analyses were completed after publication of NUREG-1150,

and 23 of the analyses used MACCS2, which was released in 1997. Table 5-16 shows that the

core damage frequencies estimated for the ABWR and surrogate AP1000 reactors are

| significantly lower than those of current-generation reactors. Similarly, the population doses

estimated for the advanced reactors at the Grand Gulf ESP site are well below the mean and

median values for current generation reactors undergoing license renewal.

The population dose estimates and risks for the Grand Gulf ESP site in Tables 5-13 through

5-16 are based on the 2002 population for the region. Growth estimates in the environmental
Operation Impacts at the Proposed Site

April 2006 5-77 NUREG-1817

report indicate that the population in the region is expected to grow by a factor of 1.18 from

2002 to 2070 (SERI 2005a). The population risks for the ESP site may be multiplied by this |

factor to account for population growth. Even with this increase, the risks associated with either

the ABWR or surrogate AP1000 reactors are low.

The staff compared the risk estimates given in Tables 5-13 and 5-14, the air pathway risks in

Tables 5-15 and 5-16, and the average individual early fatality and average individual latent

cancer fatality risks in Table 5-15 with the Commission’s safety goals. Preliminary information

on the IRIS and the ACR-700 reactor designs indicates that the surrogate AP1000 will likely

bound the risk for these advanced reactor designs. Similarly, the ESBWR risk is expected to

be bounded by the risk for the ABWR. Based on these comparisons, the staff concludes that

the impacts for the proposed Grand Gulf ESP site for the air pathway releases for severe

accidents would be small for operation of advanced LWRs. 

For the evaluation in this EIS to bound a non-LWR reactor design selected at the CP or COL |

stage, an applicant referencing the Grand Gulf ESP would need to demonstrate that the |

environmental impacts of the air pathway releases for severe accidents at the Grand Gulf ESP

site remain bounded by the environmental impacts from the surrogate designs. |

5.10.2.2 Surface Water Pathways

Surface water pathways are an extension of the air pathway. These pathways cover the effects

of radioactive material deposited on open bodies of water. The surface water pathways of

interest include exposure to external radiation from submersion in water and activities near the

water, ingestion of water, and ingestion of fish and other aquatic creatures. Of these pathways,

the MACCS2 code only evaluates the ingestion of contaminated water. The risks associated

with this surface water pathway calculated for the Grand Gulf ESP site are included in the last

columns of Tables 5-13 and 5-14. 

For each accident class, the population dose risk from ingestion of water is a small fraction of

the dose risk from the air pathway. These dose estimates are conservative because there are

no known downstream intakes within 160 km (100 mi) of the Grand Gulf ESP site that use the

Mississippi River as a potable water supply. None of the public water supply systems in

Mississippi that use surface water as a source are within 80 km (50 mi) of the ESP site

(SERI 2005a), and there are only five public water supply systems in Louisiana within 80 km |

(50 mi) of the site that use surface water as a source (LDEQ 2001). Four of these withdraw

water from Lake Bruin, which is about 13 km (8 mi) west-southwest of the site. The other water

supply system that uses surface water is about 64 km (40 mi) to the south-southwest.

The Mississippi River is used for recreational activities including swimming and fishing. Doses

from these surface water pathways are not modeled in MACCS or MACCS2. The GEIS 

(NRC 1996) considered typical population exposure risk for the aquatic food pathway for plants
Operation Impacts at the Proposed Site

NUREG-1817 5-78 April 2006

located on large rivers. For plants on large rivers, the population dose from the food pathway

was well below the population dose from the air pathway. The proposed Grand Gulf ESP site is

classified as being on a large river. Analysis of water-related exposure pathways at the Fermi

reactor (NRC 1981b) suggests that population exposures from swimming are significantly lower

than exposures from the aquatic ingestion pathway.

After considering the water ingestion dose estimates and the GEIS (NRC 1996), the staff

concludes that the impacts for the proposed Grand Gulf ESP site from surface water pathway

releases for severe accidents are small for operation of ABWR and surrogate AP1000 reactors.

In a similar fashion to the air pathway, the environmental impacts of the surface water pathways

for other advanced LWRs are expected to be bounded by the ABWR and the surrogate

| AP1000. For the evaluation in this EIS to bound a non-LWR reactor design selected at the CP

| or COL stage, an applicant referencing the Grand Gulf ESP would need to demonstrate that the

environmental impacts of the surface water pathway releases for severe accidents at the Grand

Gulf ESP site remain bounded by the environmental impacts from the surrogate designs.

5.10.2.3 Groundwater Pathway

Neither MACCS nor MACCS2 evaluates the environmental risks associated with severe

accident releases of radioactive material to groundwater. However, this pathway has been

| addressed in the GEIS in the context of renewal of operating licenses for the current generation

reactors (NRC 1996). The GEIS assumes a 1 x 10-4 Ryr-1 probability of occurrence of a severe

accident with a basemat melt-through leading to potential groundwater contamination, and the

staff concluded that groundwater generally contributed a small fraction of the risk attributable to

the atmospheric pathway. Although the staff assumed that the probability of occurrence of a

release via the groundwater pathway is significantly larger than a release via the atmospheric

pathway for either the ABWR or the surrogate AP1000, the groundwater pathway is more

tortuous and affords a greater time for implementing protective actions and, therefore, results in

a lower risk to the public. As a result, the staff concludes that the risks associated with releases

to groundwater are small for the proposed Grand Gulf ESP site.

5.10.2.4 Summary of Severe Accident Impacts

Although SERI chose the PPE approach in the overall ESP application, it based its evaluation

of the environmental impact of severe accidents on characteristics of the ABWR and the

| surrogate AP1000 reactor designs (SERI 2005a). The NRC staff reviewed the analysis in the

| environmental report and conducted its own confirmatory analysis using the MACCS2 code. 

The results of both the SERI analysis and the NRC analysis indicate that the environmental

risks associated with severe accidents if an advanced LWR were to be located at the Grand

Gulf ESP site would be small compared to risks associated with operation of current-generation

reactors at the Grand Gulf site and other sites. These risks are well below the Commission’s
Operation Impacts at the Proposed Site

April 2006 5-79 NUREG-1817

safety goals. On these bases, the staff concludes that the probability weighted consequences

of severe accidents at the Grand Gulf ESP site are of SMALL significance for an advanced

LWR. The environmental impacts of severe accidents for designs not evaluated in this EIS,

including gas-cooled designs, are not resolved because necessary design information is |

lacking. Consequently, these impacts would need to be evaluated at the CP or COL stage. For |

the evaluation in this EIS to bound an LWR reactor design selected at the CP or COL stage, the |

staff would need to verify that the environmental impacts of severe accidents at the Grand Gulf |

ESP site remain bounded by the environmental impacts discussed herein. 

5.10.3 Summary of Postulated Accident Impacts

The staff evaluated the environmental impacts from DBAs and severe accidents using the

ABWR and the surrogate AP1000 to characterize the environmental impacts from advanced

LWRs. As described previously, preliminary information on the IRIS and the ACR-700 reactor

designs indicates that the surrogate AP1000 would likely bound the source terms for the design

basis and severe accidents. Consequently, the staff considers it likely that doses from

surrogate AP1000 DBAs would bound the doses from DBAs for the IRIS and ACR-700 designs,

and that the probability weighted consequences of severe accidents for the surrogate AP1000

would bound the probability weighted consequences for IRIS and ACR-700 severe accidents. 

Similarly, the accident source terms, DBA doses, and probability weighted consequences of

severe accidents for an ESBWR are expected to be bounded by those for an ABWR.

Based on the information provided by SERI and the NRC staff’s independent review, the staff |

concludes that the potential environmental impacts from a postulated accident from the

operation of one or more additional nuclear power units would be SMALL for the operation of |

advanced LWRs. The staff did not explicitly evaluate the design basis or severe accident |

impacts for gas-cooled reactors because of the lack of necessary design information. |

Consequently, the impacts involving gas-cooled reactor designs are not resolved. |

5.11 Measures and Controls to Limit Adverse Impacts During

Operation

The following general measures and controls on which the staff relied in their evaluation of

environmental impact during operation of the proposed new unit or units at the Grand Gulf ESP
Operation Impacts at the Proposed Site

NUREG-1817 5-80 April 2006

site include those for which SERI would be required by applicable permits (Federal, State, and

local) and authorizations as well as the feasible measures and controls contained in

| Table 5.10-1 of the environmental report (SERI 2005a):

 C Compliance with the applicable Federal, State, and local laws, ordinances, and

regulations that prevent or minimize adverse environmental impact (for example, solid

waste management, erosion and sediment control, air emission control, noise control,

storm water management, spill response and cleanup, hazardous material

management)

 C Compliance with applicable requirements of permits and licenses required for operation

| (for example, NPDES permit and operating license).

Some of these permits or approvals include:

 C Compliance with NPDES permit requirements imposed on water discharges from the

| new unit(s) (environmental report, Section 5.2) 

 C Compliance with MDEQ permit limits and regulations for installing and operating air

| emission sources (environmental report, Section 5.3)

 C Compliance with SERI and Entergy procedures applicable to environmental control and

management.

SERI specifically identified the following general plans or specific mitigation measures in its

| environmental report on which the staff relied in its evaluation:

 C Incorporating drift eliminators into design of cooling towers to minimize potential for salt

| deposition (environmental report, Sections 5.1.1, 5.3.3)

| C Maintaining natural drainage patterns as much as practicable (environmental report,

Section 5.2.1)

 C Maintaining sedimentation basins to minimize sedimentation to Hamilton Lake

| (environmental report, Sections 5.2.1, 5.2.2)

| C Disposing dredge spoils as required by ACE and MDEQ (environmental report,

Section 5.2.2)

 C Designing intake pipes/screens to minimize potential for impingement and entrainment

| (environmental report, Section 5.3.1)
Operation Impacts at the Proposed Site

April 2006 5-81 NUREG-1817

 C Maintaining/restoring bank stabilization following any construction on the river shore

(environmental report, Section 5.3.2) |

 C Using proven industrial hygiene principles to reduce worker exposure to microorganisms

(environmental report, Section 5.3.4) |

 C Treating effluents containing biocides or other chemicals prior to discharge, in

compliance with NPDES permit requirements. Onsite sanitary waste treatment would

include tertiary treatment. SERI would also develop and implement a Storm Water

Pollution Prevention Plan to manage runoff (environmental report, Section 5.5.1) |

 C Collecting and storing chemical wastes and waste petroleum products; disposing or

recycling offsite at licensed facilities (environmental report, Section 5.5.1) |

 C Developing and implementing ALARA requirements to mitigate occupational exposures

to radioactive and mixed wastes (environmental report, Section 5.5.2) |

 C Instituting flexible work hours and additional road improvements, such as traffic lights or

turn lanes, as needed to mitigate effects on local traffic (environmental report, |

Section 5.8.2)

 C Increasing revenue to Claiborne County and the town of Port Gibson to support |

emergency services (environmental report, Section 5.8.2). |

SERI evaluated the measures and controls shown in Table 5.10-1 of its environmental report |

(SERI 2005a) and considered them feasible from both a technical and economic standpoint. In |

addition, SERI expects that these measures and controls would be adequate for avoiding or

mitigating potential adverse impact associated with operation of the new unit(s). The staff |

considered these measures and controls in its evaluation of station operation impact.

5.12 Summary of Operational Impacts 

Table 5-17 shows impact level categories as SMALL, MODERATE, or LARGE as a measure of

their expected adverse impacts, if any. A brief statement in the “comments” column explains

the basis for the impact level. Some impacts, such as the addition of tax revenue for the local

economies, are likely to be beneficial. The beneficial aspect is also reflected in the “comments”

column. Impacts related to water use and water quality were estimated for the purposes of |

comparison to alternatives, but are not resolved because significant information on the |

proposed action is lacking at the ESP stage. Other issues (effects of EMF, accident impacts for |

other-than-LWR designs) are not resolved, because of the lack of information on source terms |
Operation Impacts at the Proposed Site

NUREG-1817 5-82 April 2006

| or impacts. An applicant for a CP or COL that references the Grand Gulf ESP would need to

| provide this information to enable analysis at that time.

Table 5-17. Characterization of Operational Impacts at the Grand Gulf Early Site Permit Site

Category Com ments Impact Level

| Land-use impacts –

Site and vicinity Operation of new unit(s) within existing site. 

Minimal impacts from cooling tower drift.

| SMALL

Transmission line rights-of-way

| and offsite areas

Upgrade of existing transmission line rights-ofway would be needed.| SMALL

Air quality impacts

|

Air quality impacts would be small because the

em ission sources would be operated intermittently

and emissions would be within Federal, State, and

local air quality limits.

| SMALL

Water-related impacts –

| Hydrological alterations No significant changes in surface hydrology would

| result from plant operation. 

| SMALL

| W ater use W ater use from the Mississippi River would be a

small fraction of even the lowest flows.

| Unresolved,

| likely to be

| SMALL

W ater quality Impact on water quality would be small and would

be regulated by the Mississippi Department of

Environm ental Quality.

| Unresolved,

| likely to be

| SMALL

Ecological impacts –

Terrestrial ecosystems No detectable impacts are expected. SMALL

Aquatic ecosystems Impact would be m inimal because of the use of 

| cooling towers.

| SMALL

| Threatened and endangered

species

No impacts on Federally or State-listed species

| are likely to be detectable.

| SMALL

Socioeconomic impacts –

Physical impacts SMALL

W orkers/public W orkers would use protective equipment and

receive training to mitigate any possible impact. 

The Grand Gulf location is relatively remote, so

the public would not be affected.

–

| Buildings No impacts on onsite or offsite buildings. –

| Roads Upgrades before or during construction would

cover the lesser impact of operational workforces.

–

Aesthetics Visual impacts would be minimal because of the

remote location.

–
Operation Impacts at the Proposed Site

April 2006 5-83 NUREG-1817

Table 5-17. (contd)

Category Com ments Impact Level

Socioeconomic impacts (contd) –

Demography Num ber of new employees would be small in |

proportion to population base in the region. If inmigrating population settles according to current

patterns for Grand Gulf Unit 1, the impact on Port

Gibson could be moderate to large.

LARGE |

Social and economic LARGE |

Beneficial |

Economy Increased jobs would benefit the area

economically, up to a moderate beneficial impact

(Warren County) is possible.

–

Taxes Degree of impact depends on distribution of

revenues to county or state; generally impact is

beneficial, especially for property taxes. Under

current tax law, beneficial impact of additional

taxes would be large for Claiborne County.

– |

|

|

|

|

Infrastructure and community

services

MODERATE |

Transportation Improvements made for construction would be

sufficient to cover any adverse impact from

additional operational workers.

–

Recreation Overall impacts on recreation would be minimal |

because of the remote location and fact that the

proposed ESP facility would be operating in an

area with an existing nuclear power facility.

– |

Housing Adequate housing is available in the region to

handle operational workers. 

–

Public services Adequate in region for any population increase

resulting from operation workforce. Claiborne

County may be more affected by demands on

police, fire, and medical resources.

–

Education Current schools and planned additions would

handle additional students. Claiborne County

could be more affected if worker distribution is

similar to that for existing Grand Gulf Unit 1.

–

Historic and cultural resources A cultural resource procedure would be |

implemented for minimizing impacts from routine

land disturbances.

SMALL
Operation Impacts at the Proposed Site

NUREG-1817 5-84 April 2006

Table 5-17. (contd)

Category Com ments Impact Level

| Environmental justice

|

|

|

Physical im pacts would be sm all. Economic

impacts would be large beneficial under existing

tax law.

LARGE

| Beneficial

| Nonradiological health impacts

|

Health impacts would be monitored and controlled

in accordance with Occupational Safety and

Health Administration regulations.

SMALL,

Unresolved for

| EMF

Radiological health impacts Doses to public and occupational workers would

be m onitored and controlled in accordance with

NRC limits.

SMALL

| Impacts of postulated

accidents

–

| Design basis accidents (DBAs)

|

|

|

Doses for advanced LWRs are expected to be a

small fraction of the regulatory dose limits. CP or

COL applicant would demonstrate that doses for

postulated DBAs on chosen gas-cooled reactor

designs are within regulatory limits.

SMALL for

LWR,

Unresolved for

gas-cooled

designs

Severe accidents

|

Risks for advanced LW Rs would be sm all. If a

gas-cooled reactor is selected at the CP or COL

stage, then applicant would analyze the severe

accident impact for gas-cooled reactors.

| SMALL for

LWR,

| Unresolved for

| gas-cooled

| designs

5.13 References

10 CFR Part 20. Code of Federal Regulations, Title 10, Energy, Part 20, “Standards for

Protection Against Radiation.”

10 CFR Part 50. Code of Federal Regulations, Title 10, Energy, Part 50, “Domestic Licensing

of Production and Utilization Facilities.”

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

Protection Regulations for Domestic Licensing and Related Regulatory Functions.”

| 10 CFR Part 52. Code of Federal Regulations, Title 10, Energy, Part 52, “Early Site Permits,

| Standard Design Certifications; and Combined Licenses for Nuclear Power Plants.”

10 CFR Part 100. Code of Federal Regulations, Title 10, Energy, Part 100, “Reactor Site

Criteria.”
Operation Impacts at the Proposed Site

April 2006 5-85 NUREG-1817

18 CFR Part 35. Code of Federal Regulations, Title 18, Conservation of Power and Water

Resources, Part 35, “Filing of Rate Schedules and Tariffs,” Section 28(f), FERC Order

No. 2003, “Standardization of Generator Interconnection Agreements and Procedures.” 

68 FR 49845 (August 19, 2003), FERC Statutes & Regulations 31, 146. Federal Energy |

Regulatory Commission, 2003.

24 CFR Part 51. Code of Federal Regulations, Title 24, Housing and Urban Development,

Part 51, “Environmental Criteria and Standards.”

36 CFR Part 800. Code of Federal Regulations, Title 36, Parks, Forests, and Public Property,

Part 800, “Protection of Historic Properties.”

40 CFR Part 190. Code of Federal Regulations, Title 40, Protection of Environment, Part 190,

“Environmental Radiation Protection Standards for Nuclear Power Operations.” |

40 FR 44149. September 25, 1975. “Lists of Endangered and Threatened Fauna; Final

Listing.” Federal Register.

41 FR 24062. June 14, 1976. “Endangered Status for 159 Taxa of Animals.” Federal

Register.

51 FR 30028. August 21, 1986. “Safety Goals for the Operation of Nuclear Power Plants;

Policy Statement.” Federal Register.

52 FR 21059. June 4, 1987. “Reclassification of American Alligator to Threatened Status Due

to Similarity of Appearance Throughout the Remainder of Its Range.” Federal Register.

55 FR 36641. September 6, 1990. “Endangered and Threatened Wildlife and Plants;

Determination of Endangered Status for the Pallid Sturgeon; Final Rule.” Federal Register.

66 FR 65256. December 18, 2001. “National Pollutant Discharge Elimination System: |

Regulations Addressing Cooling Water Intake Structures for New Facilities; Final Rule.” 

Federal Register. 

68 FR 13370. March 19, 2003. “Endangered and Threatened Wildlife and Plants; Designation |

of Critical Habitat for the Gulf Sturgeon; Final Rule.” Federal Register. |

69 FR 41576. July 9, 2004. “National Pollutant Discharge Elimination System-Final

Regulations to Establish Requirements for Cooling Water Intake Structures at Phase II Existing

Facilities; Final Rule.” Federal Register.
Operation Impacts at the Proposed Site

NUREG-1817 5-86 April 2006

| 69 FR 52040. August 24, 2004. “Policy Statement on the Treatment of Environmental Justice

| Matters in NRC Regulatory and Licensing Actions.” Federal Register. 

Beitinger, T.L., W.A. Bennett, and R.W. McCauley. 2000. “Temperature Tolerances of North

American Freshwater Fishes Exposed to Dynamic Changes in Temperature.” Environmental

Biology of Fishes 58:237-275.

| Bird Nature. 2004. Migration Flyways: Mississippi Flyway. Accessed on the Internet

May 7, 2004 at http://www.birdnature.com/mississippi.html.

Braaten, P.J. and D.B. Fuller. 2005. “Drift Dynamics of Larval Pallid Sturgeon in a Side

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