Regulatory Guide 4.7
| ML003739894 | |
| Person / Time | |
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| Issue date: | 04/30/1998 |
| From: | Office of Nuclear Regulatory Research |
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| References | |
| -nr RG-4.7 Rev 2 | |
| Download: ML003739894 (32) | |
U.S. NUCLEAR REGULATORY COMMISSION
Revision 2 April 1998 REGULATORY GUIDE
OFFICE OF NUCLEAR REGULATORY RESEARCH
REGULATORY GUIDE 4.7 (Draft was issued as DG-4004)
GENERAL SITE SUITABILITY
CRITERIA FOR NUCLEAR POWER STATIONS
A. INTRODUCTION
The Atomic Energy Act of 1954 (42 U.S.C. 2011 et seq.), as amended, and the Energy Reorganization Act of 1974 places on the Nuclear Regulatory Commission (NRC) the responsibility for the licensing and regula tion of private nuclear facilities from the standpoint of public health and safety. Part 100, "Reactor Site Crite ria," of Title 10 of the Code of Federal Regulations re quires that the population density; use of the site envi rons, including proximity to man-made hazards; and the physical characteristics of the site, including seismology, meteorology, geology, and hydrology, be
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taken into account in determining the acceptability of a site for a nuclear power reactor. Seismic and geologic site criteria for nuclear power plants are provided inAp pendix A and in 10 CFR 100.2
3. Appendix A to
10 CFR Part 50 establishes minimum requirements for the principal design criteria for water-cooled nuclear power plants, and Appendix S to Part 50 provides engi neering criteria for nuclear power plants. A number of these criteria are directly related to site characteristics as well as to events and conditions outside the nuclear power unit.
The National Environmental Policy Act of 1969 (NEPA) (42 U.S.C. 4321 et seq.), as amended, imple mented by Executive Orders 11514 and 11991 and the Council on Environmental Quality's Guidelines (40
CFR Parts 1500-1508), requires that all agencies of the Federal Government prepare detailed environmental statements on proposed major Federal actions that can significantly affect the quality of the human environ ment. A principal objective of NEPA is to require the Federal agency to consider, in its decision-making pro cess, the environmental impacts of each proposed ma jor action and the available alternative actions, includ ing alternative sites.
Part 51, "Environmental Protection Regulations for Domestic Licensing and Related Regulatory Func tions," of Title 10 of the Code of Federal Regulations sets forth the NRC's policy and procedures for the prep aration and processing of environmental impact state ments and related documents pursuant to Section
102(2)(C) of NEPA.
The limitations on the Commission's authority and responsibility pursuant to the NEPA imposed by the Clean Water Act [Federal Water Pollution Control Act (FWPCA)] (33 U.S.C. 1251 et seq.), as amended, are addressed in the Policy Statement Regarding Imple mentation of Certain NRC and EPA Responsibilities published in the Federal Register on December 31,
1975 (40 FR 60115).
USNRC REGULATORY GUIDES
The guides are issued in the following ten broad divisions:
Regulatory Guides are issued to describe and make available to the public such informa tion as methods acceptable to the NRC staff for implementing specific parts of the Coin-
1. Power Reactors
6.
Products mission's regulations, techniques used by the staff in evaluating specific problems or pos-
2. Research and Test Reactors
7. Transportation tulated accidents, and data needed by the NRC staff in its review of applications for per-
3. Fuels and Materials Facilities
8. Occupational Health mits and licenses. Regulatory guides are not substitutes for regulation
s. and compliance
4. Environmental and Siting
9, Antitrust and Financial Review with them is not required. Methods and solutions different from those set out in the guides S. Materials and Plant Protection
10. General will be acceptable if they provide a basis for the findings requisite to the issuance or con tinuance of a permit or license by the Commission.
Single copies of regulatory guides may be obtained free of charge by writing the Repro This guide was issued after consideration of comments received from the public. Coin- duction and Distribution Services Section. Office of the Chief Information Officer. U.S. Nu ments and suggestionsfor improvements inthese guides are encouraged at all times, and clear Regulatory Commission, Washington. DC 20555-0001: or by fax at (301)415-5272.
guides will be revised, as appropriate, to accommodate comments and to reflect new in formation or experience.
Issued guides may also be purchased from the National Technical Information Service on Written comments may be submitted to the Rules and Directives Branch. ADM. U.S. Nu- a standing order basis. Details on this service may be obtained by writing NTIS. 5285 Port clear Regulatory Commission, Washington. DC 20555-0001.
Royal Road, Springfield. VA 22161.
This guide discusses the major site characteristics related to public health and safety and environmental issues that the NRC staff considers in determining the suitability of sites for light-water-cooled (LWR) nu clear power stations. 1 The guidelines may be used by applicants in identifying suitable candidate sites for nu clear power stations. The decision that a station may be built on a specific candidate site is based on a detailed evaluation of the proposed site-plant combination and a cost-benefit analysis comparing it with alternative site plant combinations as discussed in Regulatory Guide
4.2, "Preparation of Environmental Reports for Nu clear Power Stations." 2 Chapter 9 of Regulatory Guide 4.2 discusses the selection of a site from among alternative sites; the ap plicant should present its site-plant selection process as the consequence of an analysis of alternatives whose environmental costs and benefits were evaluated and compared and then weighed against those of the pro posed facility.
This guide is intended to assist applicants in the ini tial stage of selecting potential sites for a nuclear power station. Each site that appears to be compatible with the general criteria discussed in this guide will have to be examined in greater detail before it can be considered to be a "candidate" site, i.e., one of the group of sites that are to be considered in selecting a "proposed" or "pre ferred" site.3 This guide should be used only in the initial stage of site selection because it does not provide detailed guidance on the various relevant factors and format for ranking the relative suitability or desirability of pos sible sites. This guide provides a general set of safety and environmental criteria that the NRC staff has found
1For the purpose of this guide, nuclear power station refers to the nu clear reactor unit or units, nuclear steam supply, electric generating units, auxiliary systems including the cooling system and structures such as docks that are located on a given site, and any new electrical transmission towers and lines erected in connection with the facilities.
2Copies are available for inspection or copying for a fee from the NRC
Public Document Room at 2120 L Street NW, Washington, DC; the PDR's mailing address is Mail Stop LL-6, Washington, DC
20555-0001; telephone (202)634-3273; fax (202)634-3343. Copies of regulatory guides, both active and draft, may be obtained free of charge by writing the Reproduction and Distribution Services Section, OCIO, USNRC, Washington, DC 20555-0001, or by fax at
(301)415-5272; or at current rates from the National Technical Infor mation Service by writing NTIS at 5285 Port Royal Road, Springfield, VA 22161.
3See Chapter 9 of Regulatory Guide 4.2 for a discussion of site selection procedures. The "proposed" site submitted by an applicant for a construction permit is that site chosen from a number of "candidate"
sites the applicant prefers and on which the applicant proposes to construct a nuclear power station.
to be valuable in assessing candidate site identification in specific licensing cases.
The information needed to evaluate potential sites at this initial stage of site selection is assumed to be lim ited to information that is obtainable from published re ports, public records, public and private agencies, and individuals knowledgeable about the locality of a po tential site. Although in some cases the applicants may have conducted on-the-spot investigations, it is as sumed here that these investigations would be limited to reconnaissance-type surveys at this stage in the site selection process.
The safety issues discussed include geologic/
seismic, hydrologic, and meteorological characteristics of proposed sites; exclusion area and low population zone; population considerations as they relate to pro tecting the general public from the potential hazards of serious accidents; potential effects on a station from ac cidents associated with nearby industrial, transporta tion, and military facilities; emergency planning; and security plans. The environmental issues discussed concern potential impacts from the construction and operation of nuclear power stations on ecological sys tems, water use, land use, the atmosphere, aesthetics, and socioeconomics.
This guide does not discuss details of the engineer ing designs required to ensure the compatibility of the nuclear station and the site or the detailed information required for the preparation of the safety analysis and environmental reports. In addition, nuclear power reac tor site suitability as it may be affected by the Commis sion's materials safeguards for nuclear power plants is not addressed in this guide.
A significant commitment of time and resources may be required to select a suitable site for a nuclear power station, including safety and environmental con siderations. Site selection involves consideration of public health and safety, engineering and design, eco nomics, institutional requirements, environmental im pacts, and other factors. The potential impacts of the construction and operation of nuclear power stations on the physical and biological environment and on social, cultural, and economic features 4 (including environ mental justice) are usually similar to the potential im
4Biological and physical environment includes geology, geomorpholo gy, surface and groundwater hydrology, climatology, air quality, limnology, water quality, fisheries,wildlife, and vegetation. Social and cultural features include scenic resources, recreation resources, ar cheological and historical resources, and community resources, in cluding land use patterns.
4.7-2
pacts of any major industrial facility, but nuclear power stations are unique in the degree to which potential impacts of the environment on their safety must be con j.
sidered. The safety requirements are primary determi nants of the suitability of a site for nuclear powel stations, but considerations of environmental impacts are also important and need to be evaluated.
In the site selection process, coordination between applicants for nuclear power stations and various Fed eral, State, local, and Native American tribal agencies will be useful in identifying potential problem areas.
Appendices A and B of this guide summarize the important safety-related and environmental consider ations for assessing the site suitability of nuclear powei stations.
The information collections contained in this regu latory guide are covered by the requirements of 10 CFR
Part 50, which were approved by the Office of Manage ment and Budget, approval number 3150-0011. The NRC may not conduct or sponsor, and a person is no'
required to respond to, a collection of information un less it displays a currently valid OMB control number
B. DISCUSSION
~
GEOLOGY AND SEISMOLOGY
Nuclear power stations must be designed to pre.
vent the loss of safety-related functions. Generally, th(
most restrictive safety-related site characteristics con.
sidered in determining the suitability of a site are sur.
face faulting, potential ground motion and foundatior conditions 5 (including liquefaction, subsidence, anc landslide potential), and seismically induced floods Criteria that describe the nature of the investigations re quired to obtain the geologic and seismic data neces sary to determine site suitability have been set forth it
10 CFR Part 100, "Reactor Site Criteria," in Sectiol
100.23, "Geologic and Seismic Siting Criteria" (59 FF
52255). Safety-related site characteristics are identifiec in Section 2.5 of Regulatory Guide 1.70, "Standarc Format and Content of Safety Analysis Reports for Nu clear Power Plants,"'2 Regulatory Guide 1.165, "Identi fication and Characterization of Seismic Sources anc Determination of Safe Shutdown Earthquake Groun(
5WJ. Hall, N.M. Newmark, and A.J. Hendron,Jr.,"Classification, Engi neering Properties and Field Exploration of Soils, Intact Rock and Ii Situ Rock Masses" (WASH- 1301, May 1974), outlines some of thi procedures used to evaluate site foundation properties. Copies an available for inspection or copying for a fee from the NRC Public Doc ument Room at 2120 L Street NW., Washington, DC; the PDR's mail ing address is Mail Stop LL-6. Washington, DC 20555-0001; tele phone (202)634-3273; fax (202)634-3343.
r Motion,"2 and Regulatory Guide 1.59, "Design Basis Floods for Nuclear Power Plants." 2 In addition to geo
-
logic and seismic evaluation for assessing seismically
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induced flooding potential, Section 2.4 of Regulatory r
Guide 1.70 and Regulatory Guide 1.59 describe hydro logic criteria, including coincident flood events that should be considered.
ATMOSPHERIC EXTREMES AND
DISPERSION
The potential effect of natural atmospheric ex tremes (e.g., tornadoes 6 and exceptional icing condi tions7) on the safety-related structures of a nuclear sta
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tion must be considered. However, the atmospheric r
extremes that may occur at a site are not normally criti cal in determining the suitability of a site because safety-related structures, systems, and components can be designed to withstand most atmospheric extremes.
The atmospheric characteristics at a site are an im
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portant consideration in evaluating the dispersion of ra dioactive effluents from both postulated accidents and routine releases in gaseous effluents. 8 In addition to meeting the NRC requirements for the dispersion of airborne radioactive material, the station must meet State and Federal requirements of the Clean Air Act (42 U.S.C. 7401 et seq.) as amended. This is unlikely to be an important consideration for nuclear power station
-
siting unless (1) a site is in an area where existing air e
quality is near or exceeds standards, (2) there is a poten
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tial for interaction of the cooling system plume with a
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plume containing noxious or toxic substances from a
1 nearby facility, or (3) the auxiliary generators are ex It pected to operate routinely.
The atmospheric data necessary for assessment of the potential dispersion of radioactive material are de scribed in Regulatory Guide 1.23, "Onsite Meteorolog ical Programs." 2 n
In the evaluation of potential sites, onsite meteoro I
logical monitoring can determine if the atmospheric I
6See Regulatory Guide 1.76, "Design Basis Tornado for Nuclear Power
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Plants."
-
7See Section 2.4.7 of Regulatory Guide 1.70.
d
8Radiation doses associated with routine releases of airborne radioac tive material must be kept "as low as is reasonably achievable" (ALA
RA) [see 10 CFR 20.1101(b)]. The requirements for design objectives for equipment to control releases of radioactive material in effluents
_
from nuclear power reactors are set forth in 10 CFR 50.34a. Further,
10 CFR 50.36a(a) provides that, in order to keep power reactor efflu e
ent releases ALARA, each license authorizing operation of such a fa cility will include technical specifications regarding the establishment z-
of effluent control equipment and reporting of actual release
s. Appen
_
dix I to 10 CFR Part 50 provides numerical guidance for design objec
-_
tives and technical specification requirements for limiting conditions of operation for light-water-cooled nuclear power plants.
4.7-3
conditions at a site are adequately represented by the available atmospheric data for the area. Canyons or deep valleys frequently have atmospheric variables that are substantially different from those variables meas ured for the general region. Other topographical fea tures such as hills, mountain ranges, and lake or ocean shorelines can affect the local atmospheric conditions at a site and may cause the dispersion characteristics at the site to be less favorable than those in the general area or region. More stringent design or effluent objec tives may be required in such cases.
While it is the concentration of radioactive materi als in the atmosphere at any distance from the point of release, X(Ci/m 3), that must be controlled, the ratio XJQ, where Q(Ci/sec) is the rate of release of radioac tive materials from the source, has become a commonly evaluated term because it depends only on atmospheric variables and distance from the source.
If the dispersion of radioactive material released following a design basis accident is insufficient at the boundary of the exclusion area (see the following sec tion, "Exclusion Area and Low Population Zone") or the outer boundary of the low population zone, the plant design would not satisfy the requirements in 10 CFR
50.34(a)(1). In this case, the design of the station would be required to include appropriate and adequate com pensating engineered safety features. In addition, mete orological conditions are to be determined (1) for use in the environmental report required in 10 CFR Part 51 and (2) for verification of the criteria specified in the Design Control Document for a certified plant design.
Local fogging and icing can result from water va por discharged into the atmosphere from cooling tow ers, lakes, canals, or spray ponds, but can generally be acceptably mitigated by station design and operational practices. However, some sites have the potential for severe fogging or icing because of local atmospheric conditions. For example, areas of unusually high mois ture content that are protected from large-scale airflow patterns are most likely to experience these conditions.
The impacts are generally of greatest potential impor tance relative to transportation or electrical transmis sion systems in the vicinity of a site.
A cooling system designed with special consider ation for reducing drift may be required because of the sensitivity of the natural vegetation or the crops in the vicinity of the site to damage from airborne salt par ticles. The vulnerability of existing industries or other facilities in the vicinity of the site to corrosion by drift from cooling tower or spray system drift should be con sidered. Not only are the amount, direction, and dis tance of the drift from the cooling system important, but the salt concentration above the natural background salt deposition at the site is also important in assessing drift effects. None of these considerations are critical in evaluating the suitability of a site, but they could result in special cooling system design requirements or in the need for a larger site to confine the effects of drift within the site boundary. The environmental effects of salt drift are most severe where saline water or water with high mineral content is used for condenser cooling.
Cooling towers produce cloudlike plumes that vary in size and altitude depending on the atmospheric conditions. The plumes are often a few miles in length before becoming dissipated, but the plumes themselves or their shadows could have aesthetic impacts. Visible plumes emitted from cooling towers in the vicinity of airports could cause a hazard to aviation.
EXCLUSION AREA AND LOW POPULATION
ZONE
A reactor licensee is required by 10 CFR 100.21(a)
to designate an exclusion area and to have authority to determine all activities within that area, including re moval of personnel and property. In selecting a site for a nuclear power station, it is necessary to provide for an exclusion area in which the applicant has such author ity. Transportation corridors such as highways, rail roads, and waterways are permitted to traverse the ex clusion area provided (1) these are not so close to the facility as to interfere with normal operation of the fa cility and (2) appropriate and effective arrangements are made to control traffic on the highway, railroad, or waterway in case of emergency to protect the public health and safety.
In 10 CFR 50.34(a)(1)(ii)(D)(1), the exclusion area is required to be of such a size that an individual as sumed to be located at any point on its boundary would not receive a radiation dose in excess of 25 rem total ef fective dose equivalent (TEDE) over any 2-hour period following a postulated fission product release into the containment. The required exclusion area size involves consideration of the atmospheric characteristics of the site as well as plant design.
A reactor licensee is also required by 10 CFR
100.21(a) to designate an area immediately beyond the exclusion area as a low population zone (LPZ). The size of the LPZ must be such that the distance to the bound-
4.7-4
ary of the nearest densely populated center containini more than about 25,000 residents must be at least on(
and one-third times the distance from the reactor to th(
outer boundary of the LPZ. The boundary of th(
population center should be determined upon consider ation of population distribution, not politica boundaries.
In 10 CFR 50.34(a)(1)(ii)(D)(2), the LPZ is re quired to be of such a size that an individual located oi its outer radius for the course of the postulated acciden (assumed to be 30 days) would not receive a radiatioi dose in excess of 25 rem TEDE. The size of the LPZde pends upon atmospheric dispersion characteristics an(
population characteristics of the site as well as aspect, of plant design.
POPULATION CONSIDERATIONS
As stated in 10 CFR 100.21(h), reactors should bi located away from very densely populated centers areas of low population density are generally preferred Part 100 also states that, in determining the acceptabili ty of a particular site located away from a very densel, populated center but not in an area of low density, con sideration will be given to safety, environmental, eco nomic, or other factors that may result in the site beini
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found acceptable.
Locating reactors away from densely populatei centers is part of the NRC's defense-in-depth philoso phy and facilitates emergency planning and prepared ness as well as reducing potential doses and propert, damage in the event of a severe accident. The numerica values given in this guide (see Regulatory Position 4
"Population Considerations") are generally consisten with past NRC practice and reflect consideration of se vere accidents as well as the demographic and geo graphic conditions of the United States.
EMERGENCY PLANNING
According to 10 CFR 100.21(g), "Physical charac teristics unique to the proposed site that could pose significant impediment to the development of emer gency plans must be identified."
Additionally, 10 CFR 50.47(a)(1) requires reason able assurance that adequate protective measures cai and will be taken in the event of a radiological emergen cy before an operating license for a nuclear power plar can be issued. Adequate plans must be developed fo two areas or Emergency Planning Zones (EPZs). A
stated in 10 CFR 50.47, the plume exposure pathwa EPZ for nuclear power plants generally consists of an e
area about 16 km (10 mi) in radius, and the ingestion pathway.EPZ generally consists of an area about 80 km
(50 mi) in radius.
The exact size and configuration of the EPZs should be determined in relation to local emergency re sponse needs and capabilities as they are affected by
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such conditions as demography, topography, land char I
acteristics, access routes, and jurisdictional t
boundaries.
SECURITY PLANS
According to 10 CFR 100.21(0, "Site characteris S
tics must be such that adequate security plans and meas ures can be developed." Physical protection require ments for nuclear power plants as well as special nuclear materials are described in 10 CFR Part 73. Se curity plans and measures are important to prevent plant damage and possible radiological consequences to members of the public as a result of acts of sabotage.
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Based on experience and analysis, the NRC staff V
has found that a distance of about 110 meters (360 feet)
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to any vital structure or vital .equipment generally
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would provide sufficient space to satisfy security meas g
ures specified in 10 CFR 73.55 (e.g., protected area bar riers, detection equipment, isolation zones, vehicle bar d
riers). Since the distance to the nearest exclusion area boundary is considerably greater than 110 meters (360
_
feet), the site characteristics are not normally limiting with regard to the ability to develop adequate security
.1 plans.
A possible exception occurs if the exclusion area is it traversed by a highway, railroad, or waterwa
y. Travers
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al of such routes through the exclusion area is per
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mitted, provided they are not so close that they interfere with normal operations of the facility, and provided ap propriate and effective arrangements have been made to control traffic on such routes in case of emergency. If a transportation route passes closer than about 110 me a
ters (360 feet) to a vital structure or vital equipment, r-
special measures or analyses may be needed to show that adequate security plans can be developed.
1- HYDROLOGY
n Flooding it Criteria for evaluation of seismically induced ir floods are provided in 10 CFR 100.2
3. Regulatory s
Guide 1.59, "Design Basis Floods for Nuclear Power y
Plants," 2 describes an acceptable method of determin
4.7-5
ing the design basis floods for sites along streams or rivers and discusses the phenomena producing comparable design basis floods for coastal, estuary, and Great Lakes sites. The effects of a probable maximum flood (as defined in Regulatory Guide 1.59), seiche, surge, or seismically induced flood such as might be caused by dam failures or tsunamis on station safety functions can generally be controlled by engineering design or protection of the safety-related structures, systems, and components identified in Regulatory Guide 1.29, "Seismic Design Classification.'"2 For some river valleys, flood plains, or areas along coast lines, there may not be sufficient information to make the evaluations needed to satisfy the criteria for seismi cally induced flooding. In such cases, study of the po tential for dam failure, river blockage, or diversion in the river system or distantly and locally generated sea waves may be needed to determine the suitability of a site. In lieu of detailed investigations, Regulatory Guide 1.59 and Section 2.4 of Regulatory Guide 1.70
present acceptable analytical techniques for evaluating seismically induced flooding.
Water Availability Nuclear power stations require reliable sources of water for steam condensation, service water, emergen cy core cooling system, and other functions. Where wa ter is in short supply, the recirculation of the hot cooling water through cooling towers, artificial ponds, or im poundments has been practiced.
Water requirements for nuclear power plants are that sufficient water be available for cooling during plant operation and normal shutdown, for the ultimate heat sink, and for fire protection. The limitations im posed by existing laws or allocation policies govern the use and consumption of cooling water at potential sites for normal operation. Regulatory Guide 1.27, "Ulti mate Heat Sink for Nuclear Power Plants," 2 provides guidance on water supply for the ultimate heat sink and discusses the safety requirements. Consumption of wa ter may necessitate an evaluation of existing and future water uses in the area to ensure adequate water supply during droughts for both station operation and other water users (i.e., nuclear power station requirements versus public water supply). Regulatory agencies should be consulted to avoid potential conflicts.
Where required by law, demonstration of a request for certification of the rights to withdraw or consume water and an indication that the request is consistent with appropriate State and regional programs and poli cies is to be provided as part of the application for a construction permit or operating license.
The availability of essential water during periods of low flow or low water level is an important initial consideration for identifying potential sites on rivers, small shallow lakes, or along coastlines. Both the fre quency and duration of low flow or low-level periods should be determined from the historical record and, if the cooling water is to be drawn from impoundments, from projected operating practices.
Water Quality Thermal and chemical effluents discharged to nav igable streams are governed by the Federal Water Pollu tion Control Act (FWPCA) (33 U.S.C. 1251 et seq.)
(also known as the Clean Water Act) as amended, 40
CFR Part 122,40 CFR Part 423, and State water quality standards. The applicant should also determine wheth er there are other regulations that are current at the time sites are under consideration. Section 401(a)(1) of the FWPCA requires, in part, that any applicant for an NRC construction permit, early site permit, or com bined license for a nuclear power station provide to the NRC certification from the State that any discharge will comply with applicable effluent limitations and other water pollution control requirements. In the absence of such certification, no construction permit, early site permit, or combined license can be issued by NRC un less the requirement is waived by the State or the State fails to act within a reasonable period of time. A Na tional Pollution Discharge Elimination System (NPDES) permit to discharge effluents to navigable streams pursuant to Section 402 of the FWPCA may be required for a nuclear power station to operate in com pliance with the Act, but it is not a prerequisite to an NRC construction permit, operating license, or com bined license.
Evaluations of the dispersion and dilution capabili ties and potential contamination pathways of the ground-water environment under operating and acci dent conditions with respect to present and future users are required. Potential radiological and nonradiologi cal contaminants of ground water should be evaluated.
The suitability of sites for a specific plant design in areas with a complex ground-water hydrology or of sites located over aquifers that are or may be used by large populations for domestic or industrial water sup plies or for irrigation water can only be determined after reliable assessments have been made of the potential
4.7-6
impacts of the reactor on the ground water. According ly, 10 CFR Part 100 requires that site environmental parameters, which include hydrological and meteoro logical characteristics, be characterized and used in or compared to those used in the plant PRA and environ mental analysis.
Although management of the quality of surface waters is important, water quality is not generally a de termining factor in assessing the suitability of a site since adequate design alternatives can be developed to meet FWPCA requirements and the Commission's reg ulations implementing NEPA.
The following are examples of potential environ mental effects of station construction and operation that must be assessed: physical and chemical environmen tal alterations in habitats of important species, includ ing plant-induced rapid changes in environmental con ditions; changes in normal current direction or velocity of the cooling water source and receiving water; scour ing and siltation resulting from construction and cool ing water intake and discharge; alterations resulting from dredging and spoil disposal; and interference with shoreline processes.
INDUSTRIAL, MILITARY, AND
TRANSPORTATION FACILITIES
Accidents at present or projected nearby industrial, military, and transportation facilities may affect the safety of a nuclear power station (see Section 2.2 of Re gulatory Guide 1.70). According to 10 CFR 100.21(e),
"Potential hazards associated with nearby transporta tion routes, industrial and military facilities must be evaluated and site parameters established such that po tential hazards from such routes and facilities will pose no undue risk to the type of facility proposed to be lo cated at the site."
Accidents at nearby industrial facilities such as chemical plants, refineries, mining and quarrying op erations, oil or gas wells, or gas and petroleum product storage installations may produce missiles, shock waves, flammable vapor clouds, toxic chemicals, or in cendiary fragments. These may affect the station itself or the station operators in a way that jeopardizes the safety of the station.
Accidents at nearby military facilities, such as munitions storage areas and ordnance test ranges, may threaten station safety. An otherwise unacceptable site may be shown to be acceptable if the cognizant military organization agrees to change the installation or mode of operation to reduce the likelihood or severity of po tential accidents involving the nuclear station to an ac ceptable level.
An accident during the transport of hazardous ma terials (e.g., by air, waterway, railroad, highway, or pipeline) near a nuclear power plant may generate shock waves, missiles, and toxic or corrosive gases that can affect the safe operation of the station. The conse quences of the accident will depend on the proximity of the transportation facility to the site, the nature and maximum quantity of the hazardous material per ship ment, and the layout of the nuclear station.
Airports are transportation facilities that pose spe cialized hazards to nearby nuclear power stations. Po tential threats to stations from aircraft result from the aircraft itself as a missile and from the secondary effects of a crash, e.g., fire.
The acceptability of a site depends on establishing that (1) an accident at a nearby industrial, military, or transportation facility will not result in radiological consequences that exceed the dose guideline in 10 CFR
50.34(a)(1), or (2) the accident poses no undue risk be cause it is sufficiently unlikely to occur (less than about I0-7 per year), or (3) the nuclear power station can be designed so its safety will not be affected by the acci dent.
Potentially hazardous facilities and activities with in 5 miles (8 km) of a proposed site, and major airports within 10 miles (16 km) of a proposed site, should be identified. If a preliminary evaluation of potential acci dents at these facilities indicates that the potential haz ards from shock waves and missiles approach or exceed those of the design basis tornado of the region or if po tential hazards exist such as flammable vapor clouds, toxic chemicals, or incendiary fragments, the suitabil ity of the site should be determined by a detailed evalu ation of the degree of risk imposed by the potential hazard.
The identification of design basis events resulting from the presence of hazardous materials or activities in the vicinity of a nuclear power station is acceptable if the design basis events include each postulated type of accident for which a realistic estimate of the probability of occurrence of potential radiation exposures in excess of the dose specified in 10 CFR 50.34(a)(1) exceeds approximately 10-7 per year. Because of the difficulty of assigning precise numerical values to the probability of occurrence of the types of potential hazards generally considered in determining the acceptability of sites for
4.7-7
nuclear stations, judgment must be used as to the ac ceptability of the overall risk presented by an event.
In view of the low probability events under consid eration, the probability of occurrence of the initiating events leading to potential radiological consequences in excess of the dose specified in
10 CFR
50.34(a)(1)(ii)(D)(1) should be based on assumptions that are as realistic as is practicable. In addition, be cause of the low probability events under consider ation, valid statistical data are often not available to per mit accurate quantitative calculation of probabilities.
Accordingly, a conservative calculation showing that the probability of occurrence of potential radiation ex posure in excess of the value specified in 10 CFR
50.34(a)(1) is approximately 10-6 per year is acceptable if, when combined with reasonable qualitative argu ments, the realistic probability can be shown to be lower.
The effects of design basis events have been appro priately considered if analyses of the effects of those ac cidents on the safety-related features of the proposed nuclear power station have been performed and ap propriate measures (e.g., hardening, fire protection) to mitigate the consequences of such events have been taken.
The studies described in Section 2.2 of the Stan dard Review Plan, NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nu clear Power Plants,"2 should be made to evaluate in de tail the suitability of a site in regard to potential acci dents involving hazardous materials and activities at nearby industrial, military, and transportation facilities.
Section 2.2.3 of NUREG-0800 describes evaluation procedures and criteria for potential accidents in the site vicinity.
Regulatory Guide 1.78, "Assumptions for Evaluat ing the Habitability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Re lease," 2 describes assumptions acceptable to the NRC
staff for use in assessing the habitability of the control room during and after a postulated external release of hazardous chemicals and describes criteria that are gen erally acceptable to the staff for the protection of the control room operators.
Regulatory Guide 1.91, "Evaluations of Explo sions Postulated To Occur on Transportation Routes Near Nuclear Power Plants," 2 describes a method ac ceptable to the NRC staff for determining distances from a plant to a railway, highway, or navigable water way beyond which any explosion that might occur on these routes is not likely to have an adverse effect on plant operation or prevent a safe shutdown.
Section 3.5.1.6 of the Standard Review Plan (NUREG-0800) describes review procedures regard ing potential aircraft hazards.
ECOLOGICAL SYSTEMS AND BIOTA
Areas of great importance to the local aquatic eco system may present major difficulties in assessing po tential impacts on populations of important species or ecological systems. Such areas include those used for breeding (e.g., nesting and spawning), wintering, and feeding, as well as areas where there may be seasonally high concentrations of individuals of important spe cies. 9 Where the ecological sensitivity of a site under consideration cannot be established from existing in formation, more detailed studies, as discussed in Regu latory Guide 4.2, may be necessary. Impacts of station construction and operation on the biota and ecological systems may be mitigated by design and operational practices if justifiable relative to costs and benefits. In general, the important considerations in the balancing of costs and benefits are (a) the uniqueness of a habitat or ecological system within the region under considera tion and (b) the amount of habitat or ecological system that would be destroyed or disrupted relative to the total amount of the habitat or ecological system present in the region or the vulnerability of the reproductive ca pacity of important species' populations to the effects of construction and operation of the plant and ancillary facilities.
The alteration of one or more of the existing envi ronmental conditions may render a habitat unsuitable
9A species, whether animal or plant, is important (for the purpose of this guide) if a specificcausal link can be identified between the nuclear power station and the species and if one or more of the following crite ria applies:
(1) If the species is commercially or recreationally valuable,
(2) If the species is endangered or threatened,
(3) If the species affects the well-being of some important species within criteria (1) or (2) or if it is critical to the structure and function of a valuable ecological system or is a biological indicator of radionu clides in the environment.
Endangered and threatened species are defined by the Endangered Species Act of 1973 (16 U.S.C. 1531 et seq.), as amended, as follows:
"The term 'endangered species' means any species which is in danger of extinction throughout all or a significant portion of its range other than a species of the Class Insecta determined by the Secretary to constitute a pest whose protection under the provisions of this Act would present an overwhelming and overriding risk to man." "The term 'threatened species' means any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range." Lists of endangered and threatened species are published periodically in the Federal Register by the Secre tary of the Interior.
4.7-8
as a breeding or nursery area. In some cases, organisms use identical breeding and nursery areas each year; if the characteristics of the areas are changed, breeding success may be substantially reduced or enhanced. De struction of part or all of a breeding or nursery area may cause population shifts that result in increased competi tion for the remaining suitable areas. Such population shifts cannot compensate for the reduced size of the breeding or nursery areas if the remaining suitable area is already occupied by the species. Some species will desert a breeding area because of man's activities in the proximity to the area, even in the absence of physical disturbance of the actual breeding area.
Of special concern relative to site selection are those unique or especially rich feeding areas that might be destroyed, degraded, or made inaccessible to impor tant species by station construction or operation. Evalu ation of feeding areas in relation to potential construc tion or operation impacts includes the following considerations: size of the feeding area onsite in rela tion to the total feeding area offsite, food density, time of use, location in relation to other habitats, topography relative to access routes, and other factors (including man's activities). Site modification may reduce the quality of feeding areas by destruction of a portion of the food base, destruction of cover, or both.
Construction and operation of nuclear power sta tions can create barriers to migration, occurring mainly in the aquatic environment. Narrow zones of passage for migratory animals in some rivers and estuaries may be restricted or blocked by station operation. Partial or complete blockage of a zone of passage may result from the discharge of heat or chemicals to receiving water bodies or the construction and placement of power sta tion structures in the water body. Strong-swimming aquatic animals often avoid waters of adverse quality, but larval and immature forms are usually moved and dispersed by water currents. It is therefore important in site selection that the routes and times of movement of the immature stages be considered in relation to poten tial effects.
A detailed assessment of potential impact on the species population would be required for sites where placement of intake or discharge structures would markedly disrupt normal current patterns in migration paths of important species. The potentials for impinge ment of organisms on cooling water intake structures and entrainment of organisms through the cooling sys tem are determined by a number of variables, including site characteristics, intake structure design, and place ment of the structures at the site.
Site characteristics should be considered relative to design and placement of cooling system features and the potential of the cooling system to hold fish in an area longer than the normal period of migration or to entrap resident populations in areas where they would be adversely affected, either directly or indirectly, by limited food supply or adverse temperatures. Canals or areas where cooling waters are discharged may induce fish to remain in an unnaturally warmed habitat. The cessation of station operation during winter can be le thal to these fish because of an abrupt drop in water tem perature.
LAND USE AND AESTHETICS
Many impacts on land use at the site and in the site neighborhood arising from construction and operation of the plant, transmission lines, and transportation cor ridors can be mitigated by appropriate designs and practices. Aesthetic impacts can be reduced by select ing sites where existing topography and forests can be utilized for screening station structures from nearby scenic, historical, or recreational resources. Restora tion of natural vegetation, creative landscaping, 10 and the integration of structures with the environment can mitigate adverse visual impacts.
Preconstruction archeological excavations can usually reduce losses. Short-term salvage archeology may not be sufficient if extensive or valuable archeo logical sites are found on the potential site for a nuclear station. For areas of archeological concern, the Chief Archeologist of the National Park Service is an infor mation source, as are the State Archeologist and the State or Native American tribal Liaison Officer, or both, responsible for the National Historic Preservation Act activities for a particular State, Reservation, or both.
Proposed alternative land use may render a site un suitable for a nuclear power station. For example, lands specified by a community (1) as planned for other uses or (2) as restricted to compatible uses vis-a-vis other lands may be unsuitable. Therefore, official land use plans developed by governments at any level and by re gional agencies should be consulted for possible con flicts with power station siting. A list of Federal agen cies that have jurisdiction or expertise in land use l°Station protection requirements for nuclear safeguards may influ ence landscape design and clearing of vegetation.
4.7-9
planning, regulation, or management has been pub lished by the Council on Environmental Quality.11 Another class of impacts involves the preempting of existing land use at the site itself. For example, nu clear power station siting in areas uniquely suited for growing specialty crops may be considered a type of land conversion involving unacceptable economic dis location.
Sites adjacent to lands devoted to public use may be considered unsuitable. In particular, the use of some sites or transmission lines or transportation corridors close to special areas administered by Federal, State, or local agencies for scenic or recreational use may cause unacceptable impacts regardless of design parameters.
Such cases are most apt to arise in areas adjacent to nat ural-resource-oriented areas (e.g., Yellowstone Nation al Park) as opposed to recreation-oriented areas (e.g.,
Lake Mead National Recreation Area). Some historical and archeological sites may also fall into this category.
The acceptability of sites near special areas of public use should be determined by consulting cognizant gov ernment agencies.
The following Federal agencies should be con sulted for the special areas listed:
"
National Park Service (U.S. Department of the In terior)
National Parks; International Parks; National Me morial Parks; National Battlefields, Battlefield Parks, and Battlefield Sites; National Military Parks; Historic Areas and National Historic Sites;
National Capital Parks; National Monuments and Cemeteries; National Seashores and Lakeshores;
National Rivers and Scenic Riverways; National Recreation Areas; National Scenic Trails and Scientific Reserves; National Parkways
"° National Park Service Preservation Program National Landmarks Program; Historic American Buildings Survey; National Register of Historic Places; National Historical Landmarks Program;
National Park Service Archeological Program
"° Bureau of Sport Fisheries and Wildlife (U.S. De partment of Interior)
National Wildlife Refuges t 1See U.S. Council on Environmental Quality, "National Environmen tal Policy Act (NEPA) Implementation Procedures; Appendixes I, II
and III," 49 FR 49750, December 21. 1984.
Forest Service (U.S. Department of Agriculture)
National Forest Wilderness, Primitive Areas, Na tional Forests.
Individual States and local governments adminis ter parks, recreation areas, and other public use and benefit areas. Information on these areas should be ob tained from cognizant State agencies such as State de partments of natural resources. The Advisory Council on Historic Preservation or the appropriate State or Na tive American tribal historic preservation officer should be contacted for information on historic areas.
It should be recognized that some areas may be un suitable for siting because of public interest in future dedication to public scenic, recreational, or cultural use. Relatively rare land types such as sand dunes and wetlands are examples. However, the acceptability of sites for nuclear power stations at some future time in these areas will depend on the existing impacts from in dustrial, commercial, and other developments.
SOCIOECONOMICS
Social and economic issues are important determi nants of siting policy. It is difficult both to assess the na ture of the impacts involved and to determine value schemes for predicting the level or the acceptability of potential impacts.
The siting, construction, and operation of a nuclear power station may have significant impacts on the so cioeconomic structure of a community and may place severe stresses on the local labor supply, transportation facilities, and community services in general. There may be changes in the tax basis and in community ex penditures, and problems may occur in determining equitable levels of compensation for persons relocated as a result of the station siting. It is usually possible to resolve such difficulties by proper coordination with impacted communities; however, some impacts may be locally unacceptable and too costly to avoid by any rea sonable program for their mitigation. Evaluation of the suitability of a site should therefore include consider ation of purpose and probable adequacy of socioeco nomic impact mitigation plans for such economic im pacts on any community where local acceptance problems can be reasonably foreseen.
Certain communities in the neighborhood of a site may be subject to unusual impacts that would be exces sively costly to mitigate. Among such communities are towns that possess notably distinctive cultural charac ter, i.e., towns that have preserved or restored numerous
4.7-10
places of historic interest, have specialized in an unusu al industry or avocational activity, or have otherwise markedly distinguished themselves from other communities.
Siting decisions should reflect fair treatment and meaningful involvement of all people, regardless of race, ethnicity, culture, income or educational level to assure equitable consideration and to minimize disproportionate effects on minority and low-income populations.
1 2 NOISE
Noise levels at nuclear stations occur during both the construction and operation phases and could have unacceptable impacts. Cooling towers, turbines, and transformers contribute to the noise levels during sta tion operation.
C. REGULATORY POSITION
1.
GEOLOGY AND SEISMOLOGY
Preferred sites are those with a minimal likelihood of surface or near-surface deformation and a minimal likelihood of earthquakes on faults in the site vicinity (within a radius of 8 km (5 miles)). Because of the un certainties and difficulties in mitigating the effects of permanent ground displacement phenomena such as surface faulting or folding, fault creep, subsidence or collapse, the NRC staff considers it prudent to select an alternative site when the potential for permanent ground displacement exists at the site.
Sites located near geologic structures, for which at the time of application the data base is inadequate to de termine their potential for causing surface deformation, are likely to be subject to a longer licensing process in view of the need for extensive and detailed geologic and seismic investigations of the site and surrounding region and for the rigorous analyses of the site-plant combination.
Sites with competent bedrock generally have suit able foundation conditions. In regions with few or no such sites, it is prudent to select sites with competent and stable solid soils, such as dense sands and glacial tills. Other materials may also provide satisfactory foundation conditions, but a detailed geologic and geo technical investigation would be required to determine static and dynamic engineering properties of the mate
12The NRC committed to carry out the measures set forth in Executive Order 12898, "Federal Actions to Address Environmental Justice in Minority Populations and Low-I ncome Populations" (59 FR 7629), to consider the effects of its actions on minority and low-income commu nities.
rial underlying the site in accordance with 10 CFR
100.23.
2.
ATMOSPHERIC EXTREMES AND
DISPERSION
As noted in the Discussion Section of this guide, site atmospheric conditions are site suitability charac teristics, principally with respect to the calculation of radiation doses resulting from the release of fission products as a consequence of a postulated accident. Ac cordingly, each applicant for site approval should col lect meteorological information for at least one year that is representative of the site conditions, including wind speed, wind direction, precipitation, and atmo spheric stability.
Nonradiological atmospheric considerations such as local fogging and icing, cooling tower drift, cooling tower plume lengths, and plume interactions between cooling tower plumes, as well as plumes from nearby industrial facilities, should be considered in evaluating the suitability of potential sites. The atmospheric data necessary for the assessment of nonradiological con siderations are described in Regulatory Guide 1.23,
"Onsite Meteorological Programs." 2
3.
EXCLUSION AREA AND LOW
POPULATION ZONE
An applicant for a reactor license is required by
10 CFR Part 100 to designate an exclusion area and to have authority to determine all activities within that area, including removal of personnel and property.
Transportation corridors such as highways, railroads, and waterways are permitted to traverse the exclusion area provided (1) these are not so close to the facility as to interfere with normal operation of the facility and
(2) appropriate and effective arrangements are made to control traffic on the highway, railroad, or waterway in the case of emergency to protect the public health and safety.
According to 10 CFR 50.34(a)(1)(ii)(D)(1), the ex clusion area must be of such a size that an individual as sumed to be located at any point on its boundary would not receive a radiation dose in excess of 25 rem total ef fective dose equivalent (TEDE) over any two-hour pe riod following a postulated fission product release into the containment.
An applicant is also required by 10 CFR Part 100 to designate an area immediately beyond the exclusion area as a low population zone (LPZ). The size of the LPZ must be such that the distance to the nearest
4.7-11
boundary of a densely populated center containing more than about 25,000 residents ("population center distance") must be at least one and one-third times the distance from the reactor to the outer boundary of the LPZ. The boundary of the population center should be determined upon consideration of population distribu tion, not political boundaries.
According to 10 CFR 50.34(a)(1)(ii)(D)(2), the LPZ must be of such a size that an individual located on its outer radius for the course of the postulated accident (assumed to be 30 days) would not receive a radiation dose in excess of 25 rem TEDE.
4.
POPULATION CONSIDERATIONS
As stated in 10 CFR 100.21(h), "Reactor sites should be located away from very densely populated centers. Areas of low population density are, generally, preferred. However, in determining the acceptability of a particular site located away from a very densely popu lated center but not in an area of low density, consider ation will be given to safety, environmental, economic, or other factors, which may result in the site being found acceptable."
Locating reactors away from densely populated centers is part of the NRC's defense-in-depth philoso phy and facilitates emergency planning and prepared ness as well as reducing potential doses and property damage in the event of a severe accident. Numerical values in this guide are generally consistent with past NRC practice and reflect consideration of severe acci dents, as well as the demographic and geographic con ditions characteristic of the United States.
Preferably a reactor would be located so that, at the time of initial site approval and within about 5 years thereafter, the population density, including weighted transient population, averaged over any radial distance out to 20 miles (cumulative population at a distance di vided by the circular area at that distance), does not ex ceed 500 persons per square mile. A reactor should not be located at a site whose population density is well in excess of the above value.
If the population density of the proposed site ex ceeds, but is not well in excess of the above preferred value, the analysis of alternative sites should pay partic ular attention to alternative sites having lower popula tion density. However, consideration will be given to other factors such as safety, environmental, or econom ic considerations, which may result in the site with the higher population density being found acceptable. Ex amples of such factors include, but are not limited to, the higher population density site having superior seis mic characteristics, better rail or highway access, short er transmission line requirements, or less environmen tal impact upon undeveloped areas, wetlands, or endangered species.
The transient population should be included for those sites where a significant number of people (other than those just passing through the area) work, reside part-time, or engage in recreational activities and are not permanent residents of the area. The transient popu lation should be taken into account for site evaluation purposes by weighting the transient population accord ing to the fraction of time the transients are in the area.
Projected changes in population within about 5 years after initial site approval should be evaluated for the proposed site and any alternative sites considered.
Population growth in the site vicinity after initial site approval is normal and expected and will be periodical ly factored into the emergency plan for the site, but pop ulation increases after initial site approval will not be a factor in license renewal or, by itself, used to impose other license conditions or restrictions on an operating plant.
5.
EMERGENCY PLANNING
As stated in 10 CFR 100.21(g), "Physical charac teristics unique to the proposed site that could pose a significant impediment to the development of emer gency plans must be identified."
An examination and evaluation of the site and its vicinity, including the population distribution and transportation routes, should be conducted to deter mine whether there are any characteristics that would pose a significant impediment to taking protective ac tions to protect the public in the event of emergency.
Special population groups, such as those in hospi tals, prisons, or other facilities that could require spe cial needs during an emergency, should be identified.
Physical characteristics of the proposed site that could pose a significant impediment to taking protec tive measures, such as egress limitations from the area surrounding the site, should be identified.
An evacuation time estimate (ETE) should be per formed to estimate the time periods that would be required to evacuate various sectors of the plume expo sure emergency planning zone (EPZ), including the en-
4.7-12
tire EPZ. The ETE is an emergency planning tool that assesses, in an organized and systematic fashion, the feasibility of taking protective measures for the popula tion in the surrounding area. Information on perform ing an ETE analysis is given in Appendix 4 to NUREG-0654/FEMA-REP-1, Revision 1, "Criteria for Preparation and Evaluation of Radiological Emer gency Response Plans and Preparedness in Support of Nuclear Power Plants" (November 1980).2 The value of the ETE analysis is in the methodology required to perform the analysis rather than in the calculated ETE
times. While lower ETEs may reflect favorable site characteristics from an emergency planning standpoint, there is no minimum required evacuation time in the regulations that an applicant has to meet.
6.
SECURITY PLANS
According to 10 CFR 100.21(f), "Site characteris tics must be such that adequate security plans and meas ures can be developed." Also, 10 CFR Part 73 describes physical protection requirements for nuclear power plants as well as special nuclear materials.
Generally, a distance of about 110 meters (360 feet)
to any vital structure or vital equipment would provide sufficient space to satisfy security measures of 10 CFR
-
73.55 (e.g., protected area barriers, detection equip ment, isolation zones, vehicle barriers). If the distance to a vital structure or vital equipment is less than about
110 meters (360 feet), special measures or analyses may be needed to show that adequate security plans can be developed.
7. HYDROLOGY
7.1 Flooding To evaluate sites located in river valleys, on flood plains, or along coastlines where there is a potential for flooding, the site suitability studies described in Regu latory 1.59, "Design Basis Floods for Nuclear Power Plants,"'2 should be made.
7.2 Water Availability A highly dependable system of water supply sources must be shown to be available under postulated occurrences of natural and site-related accidental phe nomena or combinations of such phenomena as dis cussed in Regulatory Guide 1.59.
To evaluate the suitability of sites, there should be reasonable assurance that permits for consumptive use of water in the quantities needed for a nuclear power plant of the stated approximate capacity and type of cooling system can be obtained by the applicant from the appropriate State, local, or regional agency.
7.3 Water Quality The potential impacts of nuclear power stations on water quality are likely to be acceptable if effluent limi tations, water quality criteria for receiving waters, and other requirements promulgated pursuant to the Feder al Water Pollution Control Act are applicable and satisfied.
The criteria in 10 CFR Parts 20 and 50 will be used by the NRC staff for determining permissible con centrations of radioactive materials discharged to sur face water or to ground water. 13
7.4 Fission Product Retention and Transport To be able to assess fission product retention and transportation via ground water, the following informa tion should be determined for the site:
"* Soil, sediment, and rock characteristics (e.g., vol canic ash, fractured limestone),
"* Absorption and retention coefficients for radioac tive materials,
"* Ground-water velocity, and
Distance to nearest body of surface water.
This information should be used in the environ mental report required in 10 CFR Part 51 and compared to the hydrological information used in the PRA or oth er analyses for a certified plant design (if such a design is to be located at the site) or used in the site-specific PRA for a custom plant located at the site.
Aquifers that are or may be used by large popula tions for domestic, municipal, industrial, or irrigation water supplies provide potential pathways for the trans port of radioactive material to man in the event of an ac cident. To evaluate the suitability of proposed sites lo cated over such aquifers, detailed studies of factors identified in Section 2.4.13 of Regulatory Guide 1.70,
"Standard Format and Content of Safety Analysis Re ports for Nuclear Power Plants,"'2 should be completed.
8. INDUSTRIAL, MILITARY, AND
TRANSPORTATION FACILITIES
According to 10 CFR 100.21(e), "Potential haz ards associated with nearby transportation routes, in
13Appendix I to 10 CFR Part 50 provides numerical guidance for design objectives and technical specification requirements for limiting condi tions of operation for light-water-cooled nuclear power stations.
4.7-13
dustrial and military facilities must be evaluated and site parameters established such that potential hazards from such routes and facilities will pose no undue risk to the type of facility proposed to be located at the site."
The acceptability of a site would depend on estab lishing that (1) an accident at a nearby industrial, mili tary, or transportation facility would not result in radio logical consequences that exceed the dose specified in
10 CFR 50.34, or (2) the accident poses no undue risk because it is sufficiently unlikely to occur (less than about 10-7 per year), or (3) the nuclear power station can be designed so its safety will not be affected by the acci dent.
Potentially hazardous facilities and activities with in 8 km (5 mi) of a proposed site, and major airports within 16km (10 mi) of a proposed site, should be iden tified. If a preliminary evaluation of potential accidents at these facilities indicates that the potential hazards from shock waves and missiles approach or exceed those of the design basis tornado for the region or there are potential hazards such as flammable vapor clouds, toxic chemicals, or incendiary fragments, the suitabil ity of the site should be determined by detailed evalua tion of the degree of risk imposed by the potential haz ard. The design basis tornado is described in Regulatory Guide 1.76, "Design Basis Tornado for Nu clear Power Plants." 2 The identification of design basis events resulting from the presence of hazardous materials or activities in the vicinity of a nuclear power station is acceptable if the design basis events include each postulated type of accident for which a realistic estimate of the probability of occurrence of doses in excess of the value specified in 10 CFR 50.34(a)(1) exceeds approximately 10-7 per year. Because of the difficulty of assigning precise numerical values to the probability of occurrence of the types of potential hazards generally considered in de termining the acceptability of sites for nuclear stations, judgment must be used as to the acceptability of the overall risk presented by an event.
In view of the low-probability events under consid eration, the probability of occurrence of initiating events leading to potential consequences in excess of the dose specified in 10 CFR 50.34(a)(1) should be based on assumptions that are as realistic as is practica ble. Because of the low-probability events under con sideration, valid statistical data are often not available to permit accurate quantitative calculation of probabili- ties. Accordingly, a conservative calculation showing that the probability of occurrence of doses in excess of the value specified in 10 CFR 50.34(a)(1) is approxi mately 10-6 per year is acceptable if, when combined with reasonable qualitative arguments, the realistic probability can be shown to be lower.
The effects of design basis events have been appro priately considered if analyses of the effects of those ac cidents on the safety-related features of a proposed nu clear station have been performed and appropriate measures (e.g., hardening, fire protection) to mitigate the consequences of such events have been taken.
9.
ECOLOGICAL SYSTEMS AND BIOTA
The ecological systems and biota at potential sites and their environs should be sufficiently well known to allow reasonably certain predictions that there would be no unacceptable or unnecessary deleterious impacts on populations of important species or on ecological systems with which they are associated from the construction or operation of a nuclear power station at the site.
When early site inspections and evaluations indi cate that critical or exceptionally complex ecological systems will have to be studied in detail to determine the appropriate plant designs, proposals to use such sites should be deferred unless sites with less complex characteristics are not available.
It should be determined whether any important species (as defined in the Discussion section of this guide under Ecological Systems and Biota) inhabit or use the proposed site or its environs. If so, the relative abundance and distribution of their populations should be considered. Potential adverse impacts on important species should be identified and assessed. The relative abundance of individuals of an important species in habiting a potential site should be compared to avail able information in the literature concerning the total estimated local population. Any predicted impacts on the species should be evaluated relative to effects on the local population and the total population of the species.
The destruction of, or sublethal effects on, a number of individuals that would not adversely affect the repro ductive capacity and vitality of a population or the crop of an economically important harvestable population or recreationally important population should general ly be acceptable, except in the case of certain endan gered species. If there are endangered or threatened spe cies at a site, the potential effects should be evaluated relative to the impact on the local population and the to-
4.7-14
tal estimated population over the entire range of the species as noted in the literature.
It should be determined whether there are any im portant ecological systems at a site or in its environs. If so, determination should be made as to whether the eco logical systems are especially vulnerable to change or if they contain important species habitats, such as breed ing areas (e.g., nesting and spawning areas), nursery, feeding, resting, and wintering areas, or other areas of seasonally high concentrations of individuals of impor tant species.
Important considerations in balancing costs and benefits include the uniqueness of a habitat or ecologi cal system within the region under consideration, the amount of the habitat or ecological system destroyed or disrupted relative to the total amount in the region, and the vulnerability of the reproductive capacity of impor tant species populations to the effects of construction and operation of the station and ancillary facilities.
If sites contain, are adjacent to, or may impact on important ecological systems or habitats that are unique, limited in extent, or necessary to the productiv ity of populations of important species (e.g., wetlands and estuaries), they cannot be evaluated as to suitability for a nuclear power station until adequate assessments for the reliable prediction of impacts have been com pleted and the facility design characteristics that would satisfactorily mitigate the potential ecological impacts have been defined. In areas where reliable and suffi cient data are not available, the collection and evalua tion of appropriate seasonal data may be required.
Migrations of important species and migration routes that pass through the site or its environs should be identified. Generally, the most critical migratory routes relative to nuclear power station siting are those of aquatic species in water bodies associated with the cooling systems. Site conditions that should be identi fied and evaluated in assessing potential impacts on im portant aquatic migratory species include (1) narrow zones of passage, (2) migration periods that are coinci dent with maximum ambient temperatures, (3) the po tential for major modification of currents by station structures, (4) the potential for increased turbidity dur ing construction, and (5) the potential for entrapment, entrainment, or impingement by or in the cooling water system or for blocking of migration by facility struc tures or effluents.
The potential for blockage of movements of impor tant terrestrial animal populations caused by the use of the site for a nuclear power station and the availability of alternative routes that would provide for mainte nance of the species' breeding population should be assessed.
If justifiable relative to costs and benefits, the po tential impacts of plant construction and operation on the biota and ecological systems can generally be miti gated by adequate engineering design and site planning and by proper construction and operations when there is adequate information about the vulnerability of the im portant species and ecological systems.
A summary of environmental considerations, pa rameters, and regulatory positions for use in evaluating sites for nuclear power stations is provided in Appendix B to this guide.
10. LAND USE AND AESTHETICS
Land use plans adopted by Federal, State, regional, or local agencies should be examined, and any conflict between these plans and use of a potential site should be resolved by consultation with the appropriate agency.
For a potential site on land devoted to specialty crop production where changes in land use might result in market dislocations, a detailed investigation should be provided to demonstrate that potential impacts have been identified.
The potential aesthetic impact of nuclear power stations at sites near natural-resource-oriented public use areas is of concern, and evaluation of such sites is dependent on consideration of specific station design layout.
1
1. SOCIOECONOMICS
The NRC staff considers that an evaluation of the suitability of nuclear power station sites near distinc tive communities should demonstrate that the construc tion and operation of the nuclear station, including transmission and transportation corridors, and poten tial problems relating to community services, such as schools, police and fire protection, water and sewage, and health facilities, will not adversely affect the dis tinctive character of the community nor disproportion ately affect minority or low-income populations. A pre liminary investigation should be made to address environmental justice considerations and to identify and analyze problems that may arise from the proximi ty of a distinctive community to a proposed site.
4.7-15
1
2. NOISE
Noise levels at proposed sites must comply with applicable Federal, State, and local noise regulations.
D. IMPLEMENTATION
The purpose of this section is to provide guidance to applicants and licensees regarding the NRC staff's plans for using this regulatory guide.
Except in those cases in which the applicant pro poses an acceptable alternative method for complying with the specified portions of the NRC's regulations, the methods in this active guide will be used in the evaluation of applications for construction permits, early site permits, operating licenses, combined li censes, or design certification. This guide would not be used in the evaluation of an application for an operating license submitted after January 10, 1997, if the construction permit was issued prior to that date.
4.7-16
APPENDIX A
SITE SAFETY CONSIDERATIONS
FOR ASSESSING SITE SUITABILITY FOR NUCLEAR POWER STATIONS
This appendix provides a checklist of site safety characteristics, relevant regulations and regulatory guides, and regulatory experience and positions for assessing site suitability for nuclear power stations.
Relevant Regulations and Considerations Regulatory Guides Regulatory Experience and Position A.1 Geology/Seismology Geologic and seismic character-
10 CFR 100.23, "Geologic and Where the potential for permanent istics of a site, such as surface Seismic Siting Factors"
ground deformation such as faulting, faulting, ground motion, and folding, subsidence, or collapse exists foundation conditions (including Regulatory Guide 1.70, Chapter at a site, the NRC staff considers it liquefaction, subsidence, and
2 (identifies safety-related site prudent to select an alternative site.
landslide potential), may affect characteristics)1 the safety of a nuclear power Sites should be selected in areas for station.
Regulatory Guide 1.29 (discusses which an adequate geologic data base plant safety features which should exists or can be expeditiously be controlled by engineering developed through site-specific design)1 investigations to identify and characterize potential geological and Regulatory Guide 1.165, "Identi- seismic hazards. Delay in licensing fication and Characterization of can result from a need for extensive Seismic Sources and Determi- geologic and seismic investigations.
nation of Safe Shutdown Conservative design of safety-related Earthquake Ground Motion"1 structures will be required when geologic, seismic, and foundation Regulatory Guide 1.132, "Site information is questionable.
Investigations for Foundations of Nuclear Power Plants" 1 Sites with competent bedrock generally have suitable foundation conditions.
If bedrock sites are not available, it is prudent to select sites in areas known to have a low subsidence and liquefaction potential. Investigations will be required to determine the static and dynamic engineering properties of the material underlying the site as stated in Appendix A to 10 CFR Part
100 and 10 CFR 100.23.
'Copies are available for inspection or copying for a fee from the NRC Public Document Room at 2120 L Street NW., Washington, DC; the PDR's mailing address is Mail Stop LL-6, Washington, DC 20555-0001; telephone (202)634-3273; fax (202)634-3343. Requests for single copies of regulatory guides should be made in writing to the U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, Attn: Reproduction and Distribution Services Section, or by fax to (301)415-5272; or guides may be purchased from the National Techni cal Information Service by writing NTIS at 5285 Port Royal Road, Springfield, VA 22161.
A-1
Relevant Regulations and Considerations Regulatory Guides Regulatory Experience and Position A.2 Atmospheric Dispersion The atmospheric conditions at a site should provide sufficient dispersion of radioactive materials released during a postulated accident to reduce the radiation exposures of individ uals at the exclusion area and low population zone boundaries to the values in 10 CFR 50.34.
10 CFR Part 50, "Domestic Licensing of Production and Utilization Facilities"
Regulatory Guide 1.23, "Onsite Meteorological Programs"'
"Atmospheric Dispersion Models for Potential Accident Conse quence Assessments at Nuclear Power Plants"'
Regulatory Guide 1.3, "Assump tions Used for Evaluating the Potential Radiological Conse quences of a Loss of Coolant Accident for Boiling Water Reactors"
1 Regulatory Guide 1.4, "Assump tions Used for Evaluating the Potential Radiological Conse quences of a Loss of Coolant Accident for Pressurized Water Reactors"1 Regulatory Guide 1.5, "Assump tions Used for Evaluating the Potential Radiological Conse quences of a Steam Line Break Accident for Boiling Water Reactors"
"Assumptions Used for Evalu ating the Potential Radiological Consequences of a Fuel Handling Accident in the Fuel Handling and Storage Facility for Boiling and Pressurized Water Reactors" 1 Unfavorable safety-related design basis atmospheric dispersion characteristics can be compensated for by engineered safety features.
Accordingly, the regulatory position on atmospheric dispersion of radiological effluents is incorporated into the section "Exclusion Area and Low Population Zone" (see A.3 of this appendix).
A-2
A-3 Relevant Regulations and Regu Considerations latory Guides Regulatory Experience and Position A.3 Exclusion Area and Low Population Zone In the event of a postulated
10 CFR Part 100, "Reactor Based on the assumptions in accident at a nuclear power Site Criteria," requires an Regulatory Guides 1.3 and 1.4, the station, radiological conse-
"exclusion area" surrounding required distances to the exclusion quences for individual members the reactor in which the area boundary and the outer boundary of the public outside the station reactor licensee has the of the LPZ will depend upon plant must be acceptably low.
authority to determine all design aspects such as the reactor activities, including exclusion power level, allowable containment or removal of personnel and leak rate, and those engineered safety property, and a "low popula- features incorporated into the design, tion zone" (LPZ) which as well as the atmospheric dispersion immediately surrounds the characteristics of the site.
exclusion area.
10 CFR Part 50, "Domestic Licensing of Production and Utilization Facilities,"
requires that at any point on the exclusion area boundary and on the outer boundary of the LPZ the exposure of an individual to a postulated release of fission products (as a consequence of an accident)
be less than 25 rem total effective dose equivalent, for specified time periods.
Regulatory Guides 1.3, 1.4,
1.5, and 1.25 give calculational methods (see A.2 of this appendix.)
Relevant Regulations and Considerations Regulatory Guides Regulatory Experience and Position A.4 Population Considerations Locating reactors away from densely populated centers is part of the NRC's defense-in-depth philosophy and facilitates emergency planning and preparedness as well as reducing potential doses and property damage in the event of a severe accident.
10 CFR Part 100, "Reactor Site Criteria," requires the following:
"An "exclusion area" surround ing the reactor in which the reactor licensee has the authority to determine all activities, including exclusion or removal of personnel and property, and a "low popula tion zone" (LPZ), which immediately surrounds the exclusion area.
"
The nearest distance to the boundary of a densely populated center containing more than about 25,000
residents must be at least one and one-third times the distance from the reactor to the outer boundary of the LPZ.
"
Reactor sites should be located away from very densely populated centers.
Areas of low population density are, generally, preferred. However, in determining the acceptability of a particular site located away from a very densely populated center but not in an area of low density, consider ation will be given to safety, environmental, economic, or other factors, which may result in the site being found acceptable.
A reactor should preferably be located such that, at the time of initial site approval and within about 5 years thereafter, the population density, including weighted transient popula tion, averaged over any radial distance out to 20 miles (cumulative popula tion at a distance divided by the area at that distance), does not exceed 500
persons per square mile. A reactor should not be located at a site whose population density is well in excess of the above value.
If the population density of the proposed site exceeds, but is not well in excess of, the preferred value, the analysis of alternative sites should pay particular attention to alternative sites having lower population density.
Consideration will be given to other factors, such as safety, environmental, or economic, which may result in the site with higher population density being found acceptable.
Transient population should be included for those sites where a significant number of people (other than those just passing through the area) work, reside part-time, or engage in recreational activities, and are not permanent residents of the area. The transient population should be taken into account by weighing the transient population according to the fraction of time the transients are in the area.
I
L
A-4
Relevant Regulations and Considerations Regulatory Guides Regulatory Experience and Position A.5 Emergency Planning To ensure that adequate protec tive measures can be taken to protect members of the public in the event of an emergency, the characteristics of the site should not preclude development of such plans.
10 CFR Part 100, "Reactor Site Criteria," requires that:
Site characteristics must be such that adequate plans to take protective actions for members of the public in the event of emergency can be developed.
10 CFR Part 50, "Domestic Licensing of Production and Utilization Facilities," requires:
" Reasonable assurance that adequate protection can and will be taken in the event of a radiological emergency.
" Emergency planning zones (EPZ) consisting of the plume exposure pathway EPZ with an area about 16 km (10 mi)
in radius, and the ingestion pathway EPZ with an area about 80 km (50 mi) in radius.
NUREG-0654/FEMA-REP-1, Rev.1, "Criteria for Preparation and Evaluation of Radiological Emergency Response Plans and Preparedness in Support of Nuclear Power Plants"
(November 1980),2 provides guidance on performing an ETE.
____________________________
I ____________________________
I
An examination and evaluation of the site should be conducted to determine whether there are any characteristics that would pose a significant impediment to taking protective actions to protect the public in the event of emergency.
Physical characteristics of the proposed site that could pose a significant impediment to taking protective actions, such as egress limitations from the area surrounding the site, should be identified.
Special population groups, such as those in hospitals, prisons, or other facilities that could require special needs during an emergency, should be identified.
An evacuation time estimate (ETE)
should be performed to estimate the time periods that would be required to evacuate various sectors of the plume exposure emergency planning zone (EPZ), including the entire EPZ. The ETE analysis is an emergency planning tool that assesses, in an organized and systematic fashion, the feasibility of taking protective measures for the population in the surrounding area. While lower ETEs may reflect favorable site characteristics from an emergency planning standpoint, there is no minimum required evacuation time an applicant must meet.
A-5
2Copies are available at current rates from the U.S. Government Printing Office, P.O. Box 37082, Washington, DC 20402-9328 (telephone
(202)512-2249); or from the National Technical Information Service by writing NTIS at 5285 Port Royal Road, Springfield, VA 22161.
Copies are available for inspection or copying for a fee from the NRC Public Document Room at 2120 L Street NW., Washington, DC; the PDR's mailing address is Mail Stop LL-6, Washington, DC 20555; telephone (202)634-3273; fax (202)634-3343.
Relevant Regulations and Considerations Regulatory Guides Regulaory Experience and Position A.6 Security Plans To prevent plant damage, and
10 CFR 100.21(f) states that site Generally, a distance of about 110
possible radiological characteristics must be such that meters to any vital structure or vital consequences to the public as a adequate security plans and equipment would provide space result of acts of sabotage, the measures can be developed, sufficient to satisfy security measures characteristics of the site should specified in 10 CFR 73.55 (e.g.,
not preclude development of Also, 10 CFR Part 73, "Physical protected area barriers, detection adequate security plans.
Protection of Plants and equipment, isolation zones, vehicle Materials," prescribes barriers).
requirements for establishment and maintenance of a physical If the distance to a vital structure or protection system for the vital equipment is less than about 110
protection of special nuclear meters, special measures or analyses materials at fixed sites and of may be required to show that adequate plants in which special nuclear security plans can be developed.
material is used.
A.7 Hydrology A.7.1 Flooding Precipitation, wind, or
10 CFR 100.23, "Geologic and To evaluate sites located in river seismically induced flooding Seismic Siting Criteria"
valleys, on flood plains, or along (e.g., resulting from dam failure, coastlines where there is a potential from river blockage or diversion, Regulatory Guide 1.59, "Design for flooding, the studies described in or from distantly and locally Basis Floods for Nuclear Power Regulatory Guide 1.59 should be generated sea waves) can affect Plants"1 made.
the safety of a nuclear power station.
"Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants" (Section
2.4)1
"General Design Criteria for Nuclear Power Plants;" Criterion
2, "Design Bases for Protection Against Natural Phenomena"
A-6
A-7 Relevant Regulations and Considerations Regulatory Guides Regulatory Experience and Position A.7.2 Water Availability A safety-related water supply is
10 CFR 100.23, "Geologic and A highly dependable system of water required for normal or Seismic Siting Criteria"
supply sources should be shown to be emergency shutdown and available under postulated occurrences cooldown.
Regulatory Guide 1.59, "Design of natural phenomena and site-related Basis Floods for Nuclear Power accidental phenomena or Plants"'
combinations of such phenomena as discussed in Regulatory Guide 1.59.
"Ultimate Heat Sink for Nuclear To evaluate the suitability of a site, Power Plants"1 there must a reasonable assurance that permits for water use and for water consumption in the quantities needed for a nuclear power plant of the stated approximate capacity and type of cooling system can be obtained by the applicant from the appropriate State, local, or regional agency.
A.7.3 Water Quality Contamination of ground water
10 CFR Part 20, "Standards for The criteria provided in 10 CFR Parts and surface water by radioactive Protection Against Radiation"
20 and 50 will be used by the NRC
materials discharged from staff for determining permissible nuclear stations could cause
10 CFR Part 50, "Licensing of concentrations of radionuclides public health hazards.
Production and Utilization discharged to surface water and Facilities"
ground water.
Relevant Regulations and Considerations Regulatory Guides Regulatory Experience and Position A.8 Industrial, Military, and Transportation Facilities Accidents at present or projected nearby industrial, military, and transportation facilities may affect the safety of the nuclear power station.
10 CFR 100.21, "Non-seismic Siting Criteria"
"General Design Criteria for Nuclear Power Plants," Criterion
4, "Environmental and Dynamic Effects Design Bases"
Regulatory Guide 1.70, "Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants," Section 2.21 (lists types of facilities and potential accidents)
"Assumptions for Evaluating the Habitability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Release"1 Potentially hazardous facilities and activities within 8 km (5 mi) and major airports within 16 km (10 mi)
of a proposed site should be identified. If a preliminary evaluation of potential accidents at these facilities indicates that the potential hazards from shock waves and missiles approach or exceed those of the design basis tornado for the region, or potential hazards such as flammable vapor clouds, toxic chemicals, or incendiary fragments exist, the suitability of the site should be determined by detailed evaluation of the potential hazard.
The acceptability of a site depends upon establishing that (1) an accident at a nearby facility or route will not result in radiological consequences that exceed the dose set forth in 10
CFR 50.34, or (2) the accident is sufficiently unlikely to occur that it poses no undue risk, or (3) the nuclear power station can be designed so its safety will not be affected by the accident.
The identification of design basis events resulting from the presence of nearby hazardous materials or activities in the vicinity of a nuclear power station is acceptable if the design basis events include each postulated type of accident for which a realistic estimate of the probability of occurrence of a potential dose in excess of that set forth in 10 CFR
50.34 exceeds approximately 10-7 per year.
A-8
APPENDIX B
ENVIRONMENTAL PROTECTION CONSIDERATIONS FOR ASSESSING
SITE SUITABILITY FOR NUCLEAR POWER STATIONS
This appendix summarizes environmental considerations related to site characteristics that should be addressed in the early site selection process. The relative importance of the different factors to be considered varies with the region or State in which the potential sites are located.
Site selection processes can be facilitated by establishing limits for various parameters based on the best judgment of specialists knowledgeable of the region under consideration. For example, limits can be chosen for the fraction of water that can be diverted in certain situations without adversely affecting the local populations of important species. Although simplistic because important factors such as the distribution of important species in the water body are not taken into account, such limits can be useful in a screening process for site selection.
Considerations I Parameters Regulatory Position B.A Preservation of Important Habitats Important habitats are those that The proportion of an important In general, a detailed justification are essential to maintaining the habitat that would be destroyed should be provided when the reproductive capacity and or significantly altered in relation destruction or significant alteration of vitality of important species to the total habitat within the more than a few percent of important populations (defined in the region in which the proposed site habitat types is proposed.
Discussion section of this guide is to be located is a useful under Ecological Systems and parameter for estimating The reproductive capacity of Biota) or the harvestable crop of potential impacts of the populations of important species and economically or recreationally construction or operation of a the harvestable crop of economically important species. Such habitats nuclear power station. The value or recreationally important include breeding areas (e.g.,
of the proportion varies among populations must be maintained nesting and spawning areas),
species and among habitats. The unless justification for proposed or nursery, feeding, resting, and region considered in determining probable changes can be provided.
wintering areas, wetlands, or proportions is the normal other areas of seasonally high geographic range of the specific concentrations of individuals of population in question.
important species.
If endangered or threatened The construction and operation species occur at a site, the of nuclear power stations potential effects of the (including new transmission construction and operation of a lines and access corridors nuclear power station should be constructed in conjunction with evaluated relative to the potential the station) can result in the impact on the local population destruction or alteration of and the total estimated habitats of important species population over the entire range leading to changes in the of species.
abundance of a species or in the species composition of a See also Chapter 2 of Regulatory community.
Guide 4.2, "Preparation of Environmental Reports for Nuclear Power Stations."1 B-1
1Copies are available for inspection or copying for a fee from the NRC Public Document Room at 2120 L Street NW
W., wasnington, DC; me PDR's mailing address is Mail Stop LL-6, Washington, DC 20555-0001; telephone (202)634-3273; fax (202)634-3343. Requests for single copies of regulatory guides should be made in writing to the U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, Attn: Reproduction and Distribution Services Section, or by fax to (301)415-5272; or guides may be purchased from the National Techni cal Information Service by writing NTIS at 5285 Port Royal Road, Springfield, VA 22161.
B-2 Considerations I Parameters Regulatory Position B.2 Migratory Routes of Important Species Seasonal or daily migrations are The width or cross-sectional area Narrow reaches of water bodies essential to maintaining the of a water body at a proposed site should be avoided as sites for locating reproductive capacity of some relative to the general width or intake or discharge structures.
important species populations, cross-sectional area in the portion of the water used by migrating A zone of passage that will permit Disruption of migratory patterns species should be estimated.
normal movement of important can result from partial or species populations and maintenance complete blockage of migratory Suggested minimum zones of of the harvestable crop of routes by structures, discharge passage range from 1/3 to 3/4 of economically important populations plumes, environmental the width or cross-sectional areas should be provided.
alterations, or human activities of narrow water bodies. 2,3 (e.g., transportation or transmission corridor clearing Some species migrate in central, and site preparation).
deeper areas while others use marginal, shallow areas. Rivers, streams, and estuaries are seldom homogeneous in their lateral dimension with respect to depth, current velocity, and habitat type.
Thus, the use of width or cross-sectional area criteria for determining adequate zones of passage should be combined with a knowledge of important species and their migratory requirements.
'Water Quality Criteria, National Academy of Sciences-National Academy of Engineering, Washington, DC, 1972.
3Handbook of Environmental Control, Volume III: Water Supply and Treatment, R.G. Bond and C.P. Straub (Editors), CRS Press, Cleveland, Ohio, 1973.
Considerations I Parameters I Regulatory Position B.3 Entrainment and Impingement of Aquatic Organisms Plankton, including eggs, larvae, The depth of the water body at The site should have characteristics and juvenile fish, can be killed the point of intake relative to the that allow placement of intake or injured by entrainment general depth of the water body structures where the relative through power station cooling in the vicinity of the site.
abundance of important species is systems or in discharge plumes.
small and where low approach The proportion of water velocities can be attained. (Deep The reproductive capacity of withdrawn relative to the net new regions are generally less productive important species' populations available water at the site is an than shallow areas. It is not implied may be impaired by lethal indirect measure of the that benthic intakes are necessary.)
stresses or by sublethal stresses destruction of plankton, which in that affect reproduction of turn is indicative of possible Important habitats (see B.1 of this individuals or result in increased effects on populations of Appendix B) should be avoided as predation on the affected species important species. It has been locations for intake structures.
population.
suggested that the fraction of available new water that can be Fish and other aquatic organisms diverted is in the range of 10% to can be killed or injured by
20% of flow.5,6 impingement on cooling water intake screens4 or by The simplistic parameter entrainment in discharge plumes.
(proportion of water withdrawal)
is suitable for use in a screening process or site selection.
However, other factors such as distribution of important species should be considered and in all cases the advice of experts on the local fisheries should be consulted to ensure that proposed withdrawals will not be excessive.
B.4 Entrapment of Aquatic Organisms Cooling water intake and Site characteristics that will Sites where the construction of intake discharge system features, such accommodate design features or discharge canals would be as canals and thermal plumes, that mitigate or prevent necessary should be avoided unless can attract and entrap organisms, entrapment.
the site and important species principally fish. The resulting characteristics are such that entry of concentration of important fish important species to the canal can be species near the station site can prevented or limited by screening.
result in higher mortalities from station-related causes, such as impingement, cold shock, or gas bubble disease, than would otherwise occur.
Entrapment can also interrupt normal migratory patterns.
4Approach velocity and screen-face velocity are design criteria that may affect the impingement of larger organisms, pnncipally nsn, on intake screens. Acceptable approach and screen-face velocities are based on swimming speeds of fish, which will vary with the species, site, and season.
5The Water's Edge: Critical Problems of the Coastal Zone, B.H. Ketchum (Editor), MIT Press, Cambridge, Mass., 1972.
6 'Engineering for Resolution of the Energy-Environment Dilemma," National Academy of Engineering, Washington, DC, 1972.
B-3
Considerations
[Parameters Regulatory Position B.5 Water Quality Effluents discharged from Applicable EPA-approved State Pursuant to Section 401(a)(1) of the nuclear power plants are water quality standards.
FWPCA, certification from the State governed under the authority of that any discharge will comply with the Federal Water Pollution For states without EPA-approved applicable effluent limitations and Control Act (FWPCA)-- (PL
water quality standards, the water other water pollution control 92-500).
quality criteria listed in Water requirements is necessary before the Quality Criteria, 1972,2 will be NRC can issue a construction permit, used for evaluation, early site permit, or combined license unless the requirement is waived by the State or the State fails to act within a reasonable length of time.
Issuance of a permit pursuant to Section 402 of the Act is not a prerequisite to an NRC license or permit.
Where station construction or operation has the potential to degrade water quality to the possible detriment of other users, more detailed analyses and evaluation of water quality may be necessary.
B.6 Water Availability The consumptive use of water Applicable Federal, State, and Water use and consumption must for cooling may be restricted by local statutory requirements.
comply with statutory requirements statute, may be inconsistent with and be compatible with water use water use planning, or may lead Compatability with water use plans of cognizant water resources to an unacceptable impact to the plan of cognizant water resource planning agencies.
water resource.
planning agency.
Consumptive use should be restricted In the absence of a water use such that the supply of other users is plan, the effect on other water not impaired and that applicable users is evaluated, considering surface water quality standards could flow or volume reduction and the be met, assuming normal station resultant ability of all users to operational discharges and extreme obtain adequate supply and to low flow conditions defined by meet applicable water quality generally accepted engineering standards (see B.5, Water practices.
Quality, of this appendix).
For multipurpose impounded lakes and reservoirs, consumptive use should be restricted such that the magnitude and frequency of drawdown will not result in unacceptable damage to important habitats (see B.1, Preservation of Important Habitats, of this appendix)
or be inconsistent with the management goals for the water body.
B-4
Considerations I Parameters Regulatory Position B.7 Established Public Amenity Areas Areas dedicated by Federal, Proximity to public amenity area.
Siting in the vicinity of designated State, or local governments to Viewability (see B.10, Visual public amenity areas will generally scenic, recreational, or cultural Amenities, of this appendix).
require extensive evaluation and purposes are generally justification.
prohibited areas for siting power stations.
The evaluation of the suitability of sites in the vicinity of public amenity Siting nuclear power stations in areas is dependent on consideration of the vicinity of established public a specific plant design and station amenity areas could result in the layout in relation to potential impacts loss or deterioration of important on the public amenity area.
public amenities.
B.8 Prospective Designated Amenity Areas Areas containing important Comparison of possible amenity Public amenity areas that are resources for scenic, recreational, areas in number and extent with distinctive, unique, or rare in a region or cultural use may not currently other similar areas available on a should be avoided as sites for nuclear be designated as such by public local, regional, or national basis, power stations.
agencies but may involve a net as appropriate.
loss to the public if converted to power generation. These areas may include locally rare land types, such as sand dunes, wetlands, or coastal cliffs.
B.9 Public Planning Land use for a nuclear power Officially adopted land use plans.
Land use plans adopted by Federal, station should be compatible State, regional, or local agencies must with established land use or be examined, and any conflict zoning plans of governmental between these plans and use of a agencies.
proposed site must be resolved by consultation with the appropriate governmental entity.
B.10 Visual Amenities The presence of power station The solid angle subtended by The visual intrusion of nuclear power structures may introduce adverse station structures at critical station structures as viewed from visual impacts to residential, viewing points, nearby residential, recreational, recreational, scenic, or cultural scenic, or cultural areas should be areas or other areas with controlled by selecting sites where significant dependence on existing topography and forests can be desirable viewing characteristics, utilized for screening station structures from those areas in which visual impacts would otherwise be unacceptable.
B-5
Considerations Parameters Regulatory Position B.11 Local Fogging and Icing Water and water vapor released Increase in number of hours of The hazards on transportation routes to the atmosphere from fogging or icing caused by from fog or ice that result from station recirculating cooling systems operation of the station.
operation should be evaluated. The can lead to ground fog and ice, evaluation should include estimates of resulting in transportation frequency of occurrence of hazards and damage to electric station-induced fogging and icing and transmission systems.
their impact on transportation, electrical transmission, and other activities and functions.
B.12 Cooling Tower Drift Concentrations of chemicals, The percent drift loss from The potential loss of important dissolved solids, and suspended recirculating condenser cooling terrestrial species and other resources solids in cooling tower drift water, particle size distribution, should be considered.
could affect terrestrial biota and salt deposition rate, local result in unacceptable damage to atmospheric conditions, and loss vegetation and other resources.
of sensitive terrestrial biota affected by salt deposition from cooling tower drift.
B.13 Cooling Tower Plume Lengths Natural draft cooling towers The number of hours per year the The visibility of cooling tower plumes produce cloud-like plumes that plume is visible as a function of as a function of direction and distance vary in size and altitude direction and distance from the from cooling towers should be depending on the atmospheric cooling towers.
considered. The evaluation should conditions. The plumes are include estimates of frequency of usually a few miles in length occurrence for plumes as well as before becoming dissipated, potential hazards to aviation in the although plume lengths of 20 to vicinity of commercial and military
30 miles have been reported airports.
from cooling towers. Visible plumes emitted from cooling towers could cause a hazard to commercial and military aviation in the vicinity of commercial and military airports. The plumes themselves or their shadows could have aesthetic impacts.
B.14 Plume Interaction Water vapor from cooling tower The degree to which impacts may The hazards to public health, plumes may interact with occur will vary depending on the structures, and other resources from industrial emissions from nearby distance between the nuclear and potential plume interaction between facilities to form noxious or fossil-fueled sites, the hours per cooling tower plumes and plumes toxic substances that could cause year of plume interaction, the from fossil-fueled sites and industrial adverse public health impacts, or type and concentration of emissions from nearby facilities result in unacceptable levels of chemical reaction produicts, the should be considered.
damage to biota, structures, and area of chemical fallout, and the other resources.
local atmospheric conditions.
B-6
B-7 Considerations Parameters Regulatory Position B.15 Noise Undesirable noise levels at Applicable Federal, State, and Noise levels at proposed sites must nuclear power stations could local noise regulations.
comply with statutory requirements.
occur during both the construction and operation phases and have unacceptable impacts near the plant.
B.16 Economic Impact of Preemptive Land Use Nuclear power stations can The level of local economic If a preliminary evaluation of net local preempt large areas, especially dislocation, such as loss of economic impact of the use of when large cooling lakes are income, jobs, and production, productive land for a nuclear power constructed. The land caused by preemptive use of station indicates a potential for large requirement is likely to be an productive land and its effect on economic dislocation, the NRC staff important issue when a proposed meeting foreseeable national will require a detailed evaluation of site is on productive land (e.g.,
demands for agriculture products.
the potential impact and justification agricultural land) that is locally for the use of the site based on a limited in availability and is cost-effectiveness comparison of important to the local economy, alternative station designs and or which may be needed to meet site-station combinations. To complete foreseeable national demands for its evaluation, the staff will also need agricultural products.
information on whether and to what extent the land use affects national requirements for agricultural products.
B.17 Environmental Justice A proposed site could have Applicable Federal, State, and Areas that disproportionately affect inequitable impacts on minority local statutory and regulatory minority or low-income populations and low-income communities.
requirements.
should be avoided as sites for nuclear power stations.
DRAFT REGULATORY ANALYSIS
A separate regulatory analysis was not prepared for this guide. The regu latory analysis prepared for the amendments to 10 CFR Parts 50 and 100
provides the regulatory basis for this guide and examines the costs and benefits of the rulemaking as implemented by the guide. A copy of the regulatory analysis is available for inspection and copying for a fee at the NRC Public Document Room, 2120 L Street NW., (Lower Level), Wash ington, DC, with the file on the amendments to 10 CFR Parts 50 and 100.
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