ML20128F313
| ML20128F313 | |
| Person / Time | |
|---|---|
| Issue date: | 10/13/1992 |
| From: | Rathbun D NRC OFFICE OF CONGRESSIONAL AFFAIRS (OCA) |
| To: | Graham B, Kostmayer P, Sharp P HOUSE OF REP., ENERGY & COMMERCE, HOUSE OF REP., INTERIOR & INSULAR AFFAIRS, SENATE, ENVIRONMENT & PUBLIC WORKS |
| References | |
| FRN-57FR47802, RULE-PR-100, RULE-PR-50, RULE-PR-52 NUDOCS 9302110337 | |
| Download: ML20128F313 (3) | |
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NUCLEAR REGULATORY COMMISSION
'E' WA3HINoTON, D.C 20686
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October 13,199?.
The Honorable Philip Sharp, Chairman Subcommittee on Energy and Power Committee on Energy and Commerce United States House of Representatives Washington, DC 20515
Dear Mr. Chairman:
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Enclosed is a proposed revision to Title 10 of_ the Code of Federal Regulations which is to be published in the Federal Reoister.
The Nuclear Regul_atory Commission is proposing to amend'its regblationsito-update the criteria used in decisiens regarding power reactor siting, including geologic, seismic, and earthquake engineering considerations for--
future nuclear power plants.- The proposed revisions would allow.the NRC-to benefit from experience' gained in the application:of the-procedures and-methods set forth in the current regulation and to" incorporate the rapid advancements in the earth sciences and earthquake engineering. The' proposed; regulation primarily consists of two-separate changes, nanely, the source term'-
and dose considerations, and the seismic and earthquake engineering; considerations of reactor < siting.
As directed by the Congress in the 1980 Authorization Act, the proposed rule would decouple reactor siting from design and would specify demographic 7 siting-criteria.
The Commission is issuing the proposed revisions-for a one hundred;twentyiday public comment period.
-Sincerely,
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P Dennis K. Rathbun,- Director
= Office of Congressional: Affairs
Enclosure:
1 Federal Register Notice-cc: The Honorable Carlos Moorhead 1
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October 13, 1992 The Honorable Peter H. Kostmayer, Chairman Subcommittee on Energy and the Environment Committee on Interior cnd Insular Affairs United States House of Representatives Washington, DC 20515
Dear Mr. Chairman:
Enclosed is a proposed revision to Title 10 of the Code of Federal Regulations which is to be published in the Federal Reaistg.
The Nuclear Regulatory Commission is proposing to amend its regulations to update the criteria used in decisions regarding power reactor siting, including geologic, :::imic, and earthquake engineering considerations for future nuclear power plants. The proposed revisions would allow the NRC to benefit from experience gained in the t.pplication of the procedures and.
methods set forth in the current regulation and to incorporate the rapio advancements in the earth sciences and earthquake engireering.
The proposed regulation primarily consists of two separate changes, namely, the source term and dose considerations, and the seismic and earthquake engineering considerations of reactor siting.
As directed by the Congress in the 1980 Authorization Act, the proposed rule would decouple reactor siting from design and w3uld specify demographic siting criteria.
The Commission is issuing the proposed revisions for a one hundred twenty-day public comment period.
Sincerely, J
dh Dennis K. Rathbua, Director Office of Congressional Affairs
Enclosure:
Federal Pegister Notice cc: The Honorable John J. Rhodes
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~ WASHINGTON, D. C. 20555 -
OctoberL13. 1992 The Honorable Bob Graham, Chairman Subcommittee on Nuclea_r Regulation Comittee on Environment and Public Works United States Senate Washington, DC 20510
Dear Mr. Chairman:
Enclosed is a proposed revision to Title 10 of the Code of Federal Regulations which is to be published in the federal-Reaister.
The Nuclear Regulatory Comission is proposing to amend its regulations to update the criteria used in decisions regarding power reactor-siting,.
including geologic, seismic, and earthquake engineering-considerations for?
future nuclear power plants. The-proposed revir. ions would allow the NRC to benefit from experience gained in the application of the procedures:and-methods set -forth in the-current regulation and to incorporate the _ rapid advancements in the earth sciences and earthquake engineering. 'The proposed regulation primarily consists of two separate changes, namely the-source-term
-and dose considerations, and the seismic and earthquake engineering _
considerations of reactor siting.
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-As directed by the Congress in the 1980 Authorization Act, the proposed rule would decouple reactor titing from design and would specify demographic sitingi criteria.
The Comission is issuing the proposed revisions for a one hundred twentyiday; public _ coment period.
Sincerely. -
l Dennis K.-Rathbun, Director-Office of Congressional Affairs-1
Enclosure:
Federal Register' Notice cc: The Honorable Alan Simpson
[7590-01]
NUCLEAR REGULATORY COMMISSION 4
10 CFR Parts 50, 52, and 100 RIN 3150-AD93 Reactor Site Criteria including Seismic and Earthquake Engineering Criteria for Nuclear Power Plants and Proposed Denial of Petition for Rulemaking from Free Environment, Inc, et. al.
AGENCY:
Nuclear Regulatory Commission.
ACTION:
Proposed rule and proposed denial of petition for rulemaking from Free Environment, Inc. et.al.
SUMMARY
The Nuclear Regulatory Commission (NRC) is -proposing to amend its regulations to update the criteria used in decisions regarding power reactor siting, including geologic, seismic, and earthquake engineering considerations-for future nuclear power plants.
The proposed rule would allow NRC to benefit from experience gained in the application of the procedures and methods set forth in the current regulation and to incorporate the rapid advancements in the earth sciences and earthquake engineering.
The proposed rule primarily consists of '
two separate changes, namely, the source term and dose considerations, and the seismic and earthquake engineering considerations of reactor siting.
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4 The Commission is also proposing to deny the remaining issue in petition (PRM-50-20) filed by Free environment, Inc. et al.
DATE: Comment period expires 120 days after date of publication in the Federal Register.
Comments received after this date will be considered if it-is practical to do so, but the Commission is able to assure consideration only for comments received on or before this date.
ADDRESSES:
Mail written comments to: Secretary, U.S.
Nuclear Regulatory Commission, Washington, DC 20555, Attention: Docketing and Service-Branch.
Deliver comments to 11555 Rockville Pike, Rockville, Maryland, between -
7:45 am and 4:15 pm, Federal workdays.
Copies of the regulatory analysis, the environmental assessment and finding of no significant impact, and comments received may be examined at the NRC Public Document Room at 2120 L Street NW. (Lower Level), Washington, DC.
FURTHER INFORMATION CONTACT: Dr. Andrew J. Murphy, Office of Nuclear _ Regulatory -
Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555, telephone (301) 492-3860, concerning the seismic and earthquake engineering aspects-and' Mr. Leonard Soffer, Office of. Nuclear Regulatory Research, U.S; Nuclear-Regulatory Commission, Washington, DC 20555, telephone (301) 492-3916, concerning other siting aspects.
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SUPPLEMENTARY.INFORMATION:
1.
Background, 11.
rojectives.
III.
Genesis.
IV.
Alternatives.
V.
Major Changes.
A.
Reactor Siting Criteria (Nonseismic).
B.
Seismic and Earthquake Engineering Criteria.
VI.
Siting Policy Task Force Recommendations.
VII.
'Related Regulatory Guides and Standard Review Plan Section.
VIII.
Future Regulatory Action.
IX.
Referenced Documents.
X.
Submission of Comments in Electronic Format.
XI.
Questions.
A.
Reactor Siting-Criteria-(Nonseismic).
B.
Seismic:and Earthquake Engineering Criteria.
-XII.
Finding of No Significant Environmental' Impact: Availability.
Xill.
Paperwork Reduction Act Statement.
XIV._
r<egulatory Analysis.
XV.
Regulatory Flexibility Certification.
XVI.
Backfit Analysis.-
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I.
Background
The present regulation regarding reactor site criteria (10 CFR Part 100) was promulgated April 12, 1962 (27 FR 3509).
Staff guidance on exclusion area and low population zone sizes as well as population density was issuad in Regu > tory Guide 4.7,
" General Site Suitability Criteria for Nuclear Power Stations," published for comment in September 1974. Revision 1 to this guide was issued in November 1975.
On June 1,1976, the Public Interest Research Group (PIRG) filed a petition for rulemaking (PRM-100-2) requesting that the NRC incorporate minimum exclusion area and low population zone distances and population density limits into the regulations.
On April 28, 1977, Free Environment, Inc. et. al., filed a petition for rulemaking (PRM-50-20).
The remaining issue of this petition requests that the central Iowa nuclear project and other reactors be sited at least 40 miles from major population centers. In August 1978, the Cenmission directed the NRC staff to develop a general policy statement on nuclear piwer reactor siting. The " Report of the Siting Policy Task Force" (NUREG-0625) was issued in August 1979 and provided recommendations -
regarding siting of future nuclear power reactors. In the 1980 Authorization Act for the NRC, the Congress directed the NRC to decouple siting from design and toi specify demographic criteria for siting. On July 29,1980 (45 FR 50350), the NRC issued an Advance Notice of Proposed Rulemaking (ANPRM) regarding revision of the reactor site criteria, which discussed the recommendations of the Siting Policy.
Task Force and sought public comments. The proposed rulemaking was deferred by the Commission in December 1981 to await development of _ a Safety Goal and-improved research on accident source terms. On August 4,1986 (51 FR 23044), the NRC issued its Policy Statement on Safety Goals that stated quantitative health objectives with regard to both prompt and latent cancer fatality risks.
On December 14, 1988 (53 FR 50232), the NRC denied PRM-100-2 on-the basis that it 4
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would unnecessarily restrict NRC's regulatory siting policies and would not result in a substantial increase in the overall protection of thd public health and safety. Because of possible renewed interest in power reactor siting, the NRC is proceeding with a rulemaking in this area.
Because 'the proposed regulations would include population density criteria for future nuclear power reactor sites, the Comission concludes that the remaining issue in PRM-50-20 is being addressed as part of this rulemaking action.
Appendix A to 10 CFR Part 100, ' Seismic and Geologic Siting Criteria for Nuclear Power Plants," was originally issued as a proposed regulation on November 25,1971 (36 FR 22601), published as a final regulation on November 13, 1973 (38 FR 31279), and became effective on December 13, 1973.
There have been two amendments to 10 CFR Part 100, Appendix A.
The first amendment, issued November 27,1973 (38 FR 32575), corrected the final regulation by adding the legend under the diagram. The second amendment resulted from a petition for rulemaking (PRM 100-1) requesting that an opinion be issued that would interpret and clarify Appendix A with respect to the determination of the Safe Shutdown Earthquake.
A notice of filing of the petition was published on May 14, 1975 (40 FR 20983).
The substance of the petitioner's proposal was-accepted and published as an
. immediately effective final regulation on January 10, 1977 (42 FR 2052).
5
II. Objectives The objectives of this proposed regulatory action are to --
- 1. State the criteria for future sites that, based upon experience and importance to risk, have been shown as key to protecting public health and safety; 2.
Provide a stable regulatory basis for seismic and geologic siting and applicable earthquake engineering design of future nuclear power plants that will
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update and i.a ify regulatory requirements and provide a flexible structure to permit censideration of new technical understandings; and 3.
Relocate the requirements that apply to plant design into 10 CFR Part 50 thereby effectively decoupling siting from plant design.
III.
Genesis The proposed regulatory action reflects changes that are intended to (1) benefit from the experience gained in applying the existing regulation and from research; (2) resolve interpretive questions; (3) provide needed regulatory flexibility to incorporate state-of-the-art improvements in the geosciences and earthquake engineering; and (4) simplify the language to a more ' plain English" text.
The proposed regulatory action would apply to applicants who apply for a construction permit, operating license, preliminary design approval, final design approval, manufacturing license, early site permit, design certification, or combined license on or after the effective date of the final regulations.
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Criteria not associated with the selection of the site or establishment of -
the Safe Shutdown Earthquake Ground Motion (SSE) have been placed into 10 CFR Part 50.
This action is consistent with the location of other design requirements in 10 CFR Part 50.
Because the revised criteria presented in the proposed regulation would not be applied to existing plants, the licensing bases for existing nuclear power plants must remain part of the regulations.
Therefore, the proposed revised reactor siting criteria would be added as Subpart B in 10 CFR Part 100 and would apply to site applications received on or after the effective data of the final' regulations. The criteria on seismic and geologic siting would be added as a new Appendix B to 10 CFR Part 100.
The dose calculations and the earthquake engineering criteria will be located in 10 CFR Part 50 (550.34(a) and Appendix S, respectively). Because Appendix S is not self executing, applicable sections of Part 50 (550.34 and 550.54) are revised to reference Appendix S. The proposed regulation would also make conforming amendments to 10 CFR Parts 52 and 100.
Sections 52.17(a)(1)(vi), and 100.20(c)(1) would be amended to note Appendix B to Part 100.
IV. Alternatives The first alternative considered by the Commission was to continue using-current regulations for site suitability determinations. This is not considered an acceptable alternative. Accident source terms and dose calculations currently influence plant design requirements rather than siting. It is desirable to state directly those siting criteria which, through importance to risk, have been shown to be key to assuring public health and safety.
Further, significant advances in the earth sciences and in earthquake engineering have taken place since the promolgation of the present regulation and deserve to be reflected in the.
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regulations.
The second alternative considered was replacement of the existing regulation with an entirely new regulation.
This is not an acceptable alternative because the provisions of the existing regulations form part of the licensing bases for many of the operating nuclear power plants and others that are in various stages of obtaining operating licenses.
Therefore, these provisions must remain in force and effect.
The approach of establishing the revised requirements in new sections and an appendix to 10 CFR Part 100 and relocating plant design requirements to 10 CFR Part 50 while retaining the existing regulation was chosen as the best alternative.
The public will benefit from a clearer, more uniform, and more consistent licensing process that incorporates updated information and is subject to fewer interpretations.
The NRC staff will benefit from improved regulatory implementation (both technical and legal), fewer interpretive debates, and increased regulatory flexibility. Applicants will derive the same benefits in addition to avoiding licensing delays caused by unclear regulatory requirements.
V. Major Changes A. Reactor Siting Criteria (Nonseismic).
Since promulgation of the reactor site criteria in 1962, the Commission has approved taore than 75 sites for nuclear power reactors and has had an opportunity to review a number of others.
As a result of these reviews, a great deal of experience has been gained regarding-the site factors that influence risk and their range of acceptability. Much of the experience gained by the NRC staff in these reviews has been reflected in the issuance of Regulatory Guide 4.7,
" General Site Suitability Criteria for Nuclear Power Stations," which was issued for comment in 1974, and revised in 1975.
It also reflects the Commission's 8
policy of keeping reactors away from densely populated centers. A review of the Regulatory Guidelines implementation has shown that its application is expected to result in low risk to the public while allowing a good selection of potential reactor sites in all regions of the nation.
The site criteria presented in the proposed regulation are based on those contained primarily in Regulatory Guide 4.7, and represent current NRC practice.
In addition, numerous risk studies on radioactive material releases tu the environment under severe accident conditions have all confirmed that the present siting practice is expected to effectively limit risk to the public.
These studies include the early " Reactor Safety Study" (WASH-1400), published in 1975, many Probabilistic Risk Assessment (PRA) studies conducted on individual plants as well as several specialized studies, and the recent " Severe Accident Risks:
An Assessment for Five U.S. Nuclear Power Plants," (NUREG-1150), issued in 1990.
The proposed criteria basically decouple siting from accident source term and dose calculations.
Experience has shown that these factors have tended to influence plant design aspects rather than siting. Accident source term and dose considerations are proposed to be applied to plant design aspects and would be relocated to Part 50.
The Commist. ion considers it appropriate, based on the extensive experience and confirmatory studies noted above, to state directly those site criteria that have been shown to be key to protecting public health and safety. These reactor site criteria are expected to be independent of plant design and, as such, are independent of the plant-type to be built at the site.
The Commission considers this appropriate because it expects'that future reactors licensed under Part 50 or Part 52 will reflect, through. their design, construction, and operation, risk characteristics that are equal to or better than existing plants. Therefore, there would be an extremely low probability for accidents that could result in release of significant quantities of radioactive fission products.
In addition, the recommendations of the Siting Policy Task 9
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force were considered in making these changes at discussed in Section X11 of this proposed rule.
Rationale for Individual Criteria
- 1. Exclusion Area. An exclusion area surrounding t.he immediate vicinity of the plant has been a requirement for siting power reactors from the very beginning. This area provides a high degree of protection to the public from a variety of potential plant accidents and also affords protection to the plant from potential can-related hazards.
The present regulation has no numerical size requirement, in terms of distance, for the exclusion area.
The present regulations assesses the consequences of a postulated radioactive fission product release within containment, coupled with assumptions regarding containment leakage, performance of certain fission product mitigation systems, and atmospheric dispersion factors for a hypothetical individual located at any point on the exclusion area boundary. The plant and site combination is considered to be acceptable if the calculated consequences do not exceed the dose values given in the present regulation.
Regulatory Guide 4.7 suggests an exclusion area distance of 0.4 miles (640 meters). This distance has been found, in conjunction with typical engineered safety features, to meet the dose values in the existing regulation.
Future reactors would be expected to be as good or better in :neeting the dose criteria at this distance.
The Commission considers an exclusion area to be an essential feature of a rr..ctor site and is retaining this requirement for future reactors. However, in keeping with the reconnendation of the Siting I'olicy Task Forct. to decouple site requirements from reactor design, the proposed regulation would eliminate the use of a postulated source term, assumptions regarding mitigation systems and 10
dispersion factors, and the calculation of radiolo '::,1 consequences to determine v
the sizes of the exclusion area and low population zone. It would instead require a minimum exclusion area distance of 0.4 miles (640 meters) for power reactors.
This distance, together with typical engineered safety features previously reviewed by the staff, has been found to satisfy the dose guidelines in the present regulation.
An exclusion area of this size or larger is fairly common for most power reactors in the U.S.
It has not been unduly difficult for most prospective applicants to find and obtain a suitable site, finally, this distance has also been found to readily satisfy the prompt fatality quantitative health objective of the Commission's Safety Goals Policy, when coupled with plant designs as reflected by those in NUREG-1150, and for a reactor power level of 3800 Megawatts (thermal).
Therefore, the minimum ev.clusion area distance proposed would assure a very low level of risk to individuals, even for those located very close to the plant.
Although an exclusion area size of about 0.4 miles is considered appropriate for reactor power levels of current designs, the Comission is also considering whether or not this size unduly penalizes potential reactors that have significantly lower power levels and is therefore requesting comments on this subject.
- 2. (2dquiation Zong.
The present regulation requires that a low population zone (l.PZ) be defined imediately beyond the exclusion area.
Residents are permitted in this area, but the number and density must be such that there is a reasonable probability that appropriate protective measures could be taken in their behalf in the event of a terious accident.
In addition, the nearest densely populated center containing mcre than about 25,000 residents must be located no closer than one and one-third times the outer radius of the LPZ.
Finally, the dose to a hypothetical individual located at the outer radius of the 11
LPZ over the entire course of the accident must not be in excess of the dose values given in the regulation.
Regulatory Guide 4.7 suggests that an outer radius of about 3 miles (4.8 km) for the LPZ has been found to satisfy the dose values in the present regulation.
Several practical problems have arisen in connection with the LPZ. Before 1980, the LPZ generally defined the distance over which public protective actions were contemplated in the event of a serious accident. The regulations in 10 CFR 50,47 now requires plume exposure Emergency Planning Zones (EPZ) of about 10 miles for each plant.
The LPZ also places restrictions on the proximity of the nearest densely populated center of 25,000 or more residents. However, without numerical requirements for the outer radius of the LPZ, this requirement has little practical effect. Typical LPZs for existing power reactors have several thousand residents, if Regulatory Guide 4.7 were followed and a distance of 3 miles were selected as the LPZ outer radius, a maximum population within the LPZ at the time of site approval would be about 14,000 residents.
Finally, the staf f has sometimes experienced difficulty in defining a ' densely populated center.*-
The Commission considers that the functions intended for the LPZ, namely, a low density of residents and the feasibility of taking protective actions, have been accomplished by other regulations or can be accomplished by other means.
Protective action requirements are defined via the use of the EPZ, while restrictions on population close to the plant can be assured via proposed population density criteria. For these reasons, the Commission is proposing to-eliminate the requirement of an LPZ for future power reactor sites for purpuses of determining site suitability.
3.
Pooulation Density criteria.
The present regulation contains no population density requirements other than the requirement, noted above, that the 12
9 distance to the nearest population center containing more than about 25,000 residents must be no closer than one and one-third times the outer radius of the LPZ. This was recognized as a potential concern when the present regulation was promulgated. As the Commission noted in its Statement of Considerations on April 12,1962 (27 FR 3509), accompanying the issuance of the regulation, '...in some cases where very large cities are involved, the population center distance may have to be greater than those suggested by these guides.'
As a result of the significant experience gained in the siting of power reactors, the staff issued Regulatory Guide 4.7 in 1974.
With respect to population density this guide states as follows:
- Areas of low population density are preferred for nuclear power station sites.
High population densities projected for any time during the lifetime of a station are considered during both the NRC staff review and the public hearing phases of the licensing process. If the population density at the proposed site is not acceptably low, then the applicant will be required to give special attention to alternative sites with lower population densities.
If the population density, including weighted transient population, projected at the time of initial operation of a nuclear power station exceeds 500 persons per square mile averaged over any radial distance out to 30 miles (cumulative population at a distance divided by the area at that distance), or the projected population density over the lifetime of the facility exceeds 1000 persons per square mile averaged over any radial distance out to 30 miles, special attention should be given to the consideration of alternative sites with lower population densities.'
The basis for this guide was that it provided for reasonable separation of 13 j
reactor sites from large population centers while also assuring an adequate selection of sites in all regions of the nation. However, no comparisons with explicit risk criteria were provided at that time.
On April 28, 1977, Free Environment, Inc. et. al., filed a petition for rulemaking (PRM-50-20) requesting, among other things, that "the central lowa nuclear project and other reactors be sited at least 40 miles from major j
population centers."
The petitioner also stated that " locating reactors in sparsely-populated areas...has been endorsed in non-binding NRC guidelines for reactor siting."
However, the petitioner did not specify what constituted a major population center. The only NRC guidelines concerning population density in regard to reactor siting are -in Regulatory Guide 4.7, issued in 1974, and revised in 1975, prior to the date of the petition.
This guide provides population density criteria out to a distance of 30 miles from the reactor, not 40 miles.
An illustration of the degree of separation distance provided for in this guide from population centers of various sizes may be useful. Under this guide, a population center of about 25,000 or more residents should be no closer than 4 miles (6.4 km) from a reactor because a density of 500 persons per square mile within this distance would yield a total population of about 25,000 persons.
Similarly, a city of 100,000 or more residents should be no closer than about 10 miles (16 km); a city of 500,000 or more persons should be no closer than about 20 miles (32-km), and a city of 1,000,000 or more persons should be no closer than about 30 miles (50 km) from the reactor.
The Commission has examined these guidelines with regard to the Safety
(
Goal. The Safety Goal quantitative health objective in regard to latent cancer fatality states that, within a distance of ten miles (16 km) from the reactor.
l the risk to the population of latent cancer fatality from nuclear power plant operation,' including accidents, should not exceed one-tenth of one percent of the 14
8 likelihood of latent cancer fatalities from all other causes. In addition to the risks of latent cancer fatalities, the Comission has also investigated the likelihood and extent of land contamination arising f rom the release of long-lived radioactive species, such as cesium-137, in the event of a severe reactor accident.
The results of these analyses indicate that the latent cancer fatality quantitative health objective noted above is met for current plant designs. From analysis done in support of this proposed change in regulation, the likelihood of land contamination from a severe accident sufficient to require long term condemnation of land beyond 30 miles (50 km) is very low.
Other analyses indicate that population density restrictions out to 40 miles could make it difficult to obtain suitable reactor sites in some regions of the nation.
Because the population density values of Regulatory Guide 4.7 havst been in use since 1975, and these values afford an adequate supply of potential reactor sites in every region of the nation while providing assurance of loer risk of latent cancer fatality as wall as land contamination, the Commission considers it prudent to maintain these population density values for future power reactor sites. The Comission wishes to emphasize, however, that nuclear power plants meeting current safety standards could be safely located at sites significantly more dense than 500 people per square mile.
For these reasons, the Commission is proposing that, at the time of initial site approval or early site permit renewal, populstion density values of no more than 500 people per square mile averaged over any radial distance out to 30 miles be used for judging the acceptability of future nuclear power plant sites.
Similarly, in keeping with Regulatory Guide 4.7, the projected population density 40 years after initial site approval should not exceed 1000 people per square mile.
With regard to the petition by Free Environment, Inc. (PRM-50-20), the 15
t Commission concludes that the criteria in Regulatory Guide 4.7 provide a reasonable degree of separation for a range of population centers, including
" major" population centers, depending upon their size.
Further, codifying the population density criteria of this guide is expected to ensure a low level of risk, including the risk of latent cancer fatality as well as long-term land contamination.
Finally, the Commission concludes that granting of the petitioner's request to specify population criteria out to 40 miles rather than 30 miles would not substantially reduce the risks to the public, but could significantly increase the difficulty of obtaining suitable reactor sites in sono regions of the nation.
For these reasons, the Commission is proposing not to adopt the proposal by Free Environment, incorporated.
An important point regarding populatien projections and their application should be made. Because the validity and reliability of population projections, particularly for relatively small regions, decreases markedly as the projection time period increases, population projections for the purpose of assessing site suitability are to be limited to 40 years.
Population projections beyond this time period become unreliable and speculative. The 40 year period for population projections is to be distinguished from the 60 year or more plant itfetime.
Because analyses have shown that current plant designs can meet the Commission's Safety Goals and that other risks can be kept at a very low level at sites that have significantly higher population densities than those being proposed, the Commission wishes to emphasize that these population density levels do not indicate the upper limits of acceptability.
These levels represent preferred values, that, if excaa J,
require that an applicant provide justification for not locating a reactor at an alternative site having a lower population density.
Therefore, the population density limits proposed in the regulation are intended to be used only in the siting decision process to be applied at the time of initial site approval or early site permit renewal to 16
_ - - - = - - -
9 determine whether alternative sites that have lower population densities should be considered. The Comission does not intend to consider license conditions or operating restrictions upon an operating reactor solely upon the basis that the population density around it may reach or exceed the proposed siting decision values given above during the plant lifetime.
Because of the possibility for confusion resulting from numerical values being cited in the regulation, the Commission is also requesting comments on whether numerical population density values should be cited in the regulation or whether these should be stated in a regulatory guide only. The Commission is also requesting comments on whether the values of 500 and 1000 persons per square mile are appropriate, and whether population density criteria need be specified out to 30 miles, or whether another distance is more appropriate.
- 4. Meteoroloaical Factors.
Radiological doses that incorporate site meteorological data need no longer be calculated for the purpose of determining _
site suitability. Meteorological data will still be needed for safety analysis and for assessing the adequacy of certain plant features, as well as to determine plant adequacy in regard to meteorological extremes, such as tornados and maximum probable precipitation.
Therefore, the proposed regulation maintains the requirement to collect and characterize meteorological data representative of the site.
The Commission has examinet the variations in site meteorology that have influenced dose calculations in past licensing reviews.
Individual site meteorology characteristics have been used primarily to determine atmospheric dispersion or dilution factors in order to evaluate doses to hypothetical individuals at the exclusion area and LPZ outer radius. The degree of dilution increases with increasing distance between the release point and any 17
hypothetically exposed individual, but it also is affected by other f actors, including the time of day, in this regard, the dispersion factor could vary significantly at a given site and show a pronounced diurnal variation. However, when the time-averaged dispersion factor of a given site is compared with that of other sites, the variation between one site and another is much less.
Analyses reported in NUREG/CR-2239, ' Technical Guidance for Siting Criteria Development,' dated December 1982, for example, show that calculated average individual consequences for an identical postulated release of radioactivity to the environment using data from weather stations throughout the United States yielded results that varied only by about a factor of two.
Based upon these considerations, the Commission has determined that the average meteorological characteristics between one site and another are sufficiently similar that characterization of individual site meteorology is not a
significant discriminator in determining site suitability when compared to the uncertainties in other areas of the determination of risk to the health and safety to the public.
However, site meteorological characteristics are needed in safety analysis and for assessing the adequacy of certain plant design features.
- 5. Hydroloaical Factors. These factors are important in establishing the magnitude of external hazards from ground-water contamination, such as by containment basemat melt through, which could contaminate aquifers and thereby af fect large populations.
The proposed regulation adds or modifies existing requirements for obtaining information to characterize hydrological factors at a site important to risk.
This information will be reviewed by the staff and used as interface criteria in matching a proposed design to the site.
- 6. Nearby Industrial and Transoortation Facilities. This area of review would be incorporated into the regulations for determining site suitability.
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This area of review has, in fact, been a part of the NRC review for many years.
The proposed regulation involves no substantive changes in this area and merely codifies what has been NRC practice for a number of years.
- 7. Feasibility of Carrvina out Protective Actions. The proposed regulation would require that important site factors such as population distribution, topography, and transportation routes be considered and examined in order to determine whether there are any site characteristics that could pose a significant impediment to the development of an emergency plan.
Planning for emergencies is part of the Comission's defense-in-depth approach.
The Comission has concluded that site characteristics that may represent an impediment to the development of adequate emergency plans, such as limitations of access or egress in the imediate vicinity of a nuclear power plant, should be identified at the site approval phase. This is consistent with the approach the Comission has taken in early site reviews under 10 CFR Part 52,
- 8. Periodic Reoortino of Man-Related Activities. Conditions around a site may change and significant changes in the nature of the industrial, military, and transportation facilities may. occur.
Early. identification of activities or facilities that are potentially hazardous could permit timely changes in the i
procedures or plant features to minimize the change in the risk to the health and safety of the public. Han-related activities potentially hazardous to a plant are typically major industrial or transport facilities such as major highways, large pipelines, major airports, etc.
Relatively minor changes in industrial i
activity have been shown to be of little concern.
l' The Comission is considering whether periodic reporting of significant offsite activities should be-required and is requesting comments on whether significant offsite facilities within -five miles of the reactor should - be:
19
periodically updated every five years.
Interim Change to 10 CFR Part 50 l
The proposed change to 10 CFR Part 50 would simply relocnte from 10 CFR Part 100 the requirements for each applicant to calculate a whole body and a thyroid dose at specified distances. Because these requirements affect reactor design rather than siting, they are more appropriately located in 10 CFR Part 50.
For this proposed revision, the source term and methodology for performing the dose calculations would remain unchanged from the current requirements.
These requirements would continue to apply to future applicants for a construction permit, design certification, or an operating license, but are i
intended to be interim requirements until such time as more specific requirements are developed regarding revised accident source terms and severe accident insights.
B. Seismic and Earthquake Engineering Criteria.
The following major changes in the proposed revision to Appendix A.
" Seismic and Geologic Siting Criterie for Nuclear Power Plants," to Part 100, are associated with the proposed seismic and earthquake engineering criteria rulemaking:
1.
jeoarate Sitina from Dejiqa, Criteria not associated with site suitability or establishment of the Safe Shutdown Earthquake Ground Motion (SSE) have been placed into 10 CFR Part 50. This action is consistent with the location of other design requirements in 10 CFR Part 50. Because-the revised criteria presented in the proposed regulation will not be applied to-existing plants, the licensing basis for existing nuclear power plants must remain part of the regulations.
The criteria on seismic and geologic siting 20
would be designated as a new Appendix B. " Criteria for the Seismic and Geologic Siting of Nuclear Power Plants on or Af ter (Effective Date of this Regulation)," to 10 CFR Part 100.
Criteria on earthquake engineering would be designated as a new Appendix S, " Earthquake Engineering Criteria for Nuclear Power Plants," to 10 CFR Part 50.
2.
Remove Detailed Guidance from the Reaulation. The current regulation contains both requirements and guidance on how to satisfy the requirements.
For example,Section IV, " Required Investigations," of Appendix A, states that investigations are required for vibratory ground motion, surface faulting, and seismically induced floods and water waves. Appendix A then provides detailed guidance on what constitutes an acceptable investigation.
A similar situation exists in Section V, " Seismic and Geologic Design Bases," of Appendix A.
Geoscience assessments require considerable latitudo in judgment. This latitude in judgment is needed because of limitations in data and the state-of-the-art of geologic and seismic analyses and because of the rapid evolution taking place in the geosciences in terms of accumulating knowledge and in modifying concepts.
This need appears to have been recognized when the existing regulation was developed.
The existing regulation states that it is based on limited geophysical and geological information and will be revised as necessary when more complete information bect tes available.
However, having geoscience assessments detailed and cast in a regulation has created difficulty for applicants and the staff in terms of inhibiting the use of needed latitude in judgment.
Also, it has inhibited flexibility in applying basic principles to new situations and the use of evolving methods of analyses (for instance, probabilistic) in the licensing process.
T1 level of detail presented in the proposed regulation would be 1
1 21
reduced considerably. The proposed regulation would identify and establish basic requirements. Detailed guidance, that is, the procedures acceptable to the NRC for meeting the requirements, would be contained in a draft regulatory guide to be issued for public comment as Draft Regulatory Guide, DG-1015
" Identification and Characterization of Seismic Sources, Deterministic Source Earthquanas, and Ground Motion."
3.
Use of Both Deterministic and probabilistic Evaluations.
The proposed regulation would require the use of both probabilistic and deterministic evaluations. The existing approach for determining a Safe 4
Shutdown Earthquake Ground Motion (SSE) for a nuclear reactor site, embodied in Appendix A to 10 CFR Part 100, relies on a " deterministic" approach. Using this deterministic approach, an applicant develops a single set of earthquake sources, develops for each source a postulated earthquake to be used as the' source of ground motion that can affect the site, locates the postulated earthquake according to prescribed rules, and then calculates ground motions at the site. Although this approach has worked reasonably well for the past two decades, in the sense that SSEs for plants sited with this approach are judged to be suitably conservative, the approach has not explicitly recognized uncertainty in geoscience parameter. ~ Because so little is known about earthquake phenomena (especially in the eastern United States), there have-always been differences of opinion among experts as to how-the p'rescribed process in Appendix-A is to be carried out.
Experts often delineate very different estimates.of the-largest earthquakes to be considered and different!
ground-motion models.
Over the past decade, analysis methods for encompassing these differences have been developed and used. These "probabilistic" methods have been designed to allow explicit-incorporation of different models-for' 22
zonation, earthquake size, ground motion, and other parameters.
The advantage of using these probabilistic methods is their ability to not only incorporate different models and different data sets, but also to weight them using judgments as to the validity of the different models and data sets, and thereby to provide an explicit expression for the overall uncertainty in the ground motion estimates and a means of assessing sensitivity to various input parameters.
Probabilistic methods have been used by many groups, not only in the seismic-hazard area but in many other areas.
In the seismic-hazard area, many of the practitioners participated in either the NRC-Lawrence Livermore National Laboratory (LLNL) or the Electric Power Research Institute (EPRI) seismic-hazard projects over the past decade.
The advantages of these probabilistic methods are manifest. However, their limitations are important too.
In the seismic-hazard area, the most important limitation is that the " bottom-line" results from these analyses tend to be dominated by the tails rather than the central tendencies of the distributions of knowledge and expert opinion.
For these reasons, the proposed revision of Appendix A to 10 CFR Part 100 has adopted an approach using both probabilistic and deterministic evaluations.
The staff proposes to use both the deterministic (currently being used) and the probabilistic evaluations together and compare the results of each to provide insights unavailable if either method were used alone. The principal limitations of the deterministic evaluation --- its ability to incorporate only one model and one data set at a time and its inability to allow weighted incorporation of numerous models --- can be assessed by comparing its results with the results of a probabilistic evaluation accomplished in parallel.
Similarly, the principal limitation of the probabilistic evaluation --- its tendency to allow its results to be dominated 23 l
by the tails rather than the central tendency of distributions of uncertain knowledge or expert opinion --- can be assessed by comparing its resalts with the results of one or more deterministic evaluations.
The NRC believes that taken together, this approach can allow more informed judgments as to what the appropriate Safe Shutdown Earthquake Ground Motion should be for a given site.
Both the applicant's judgments and those of the NRC will be improved. Therefore, the NRC believes that this approach is the best way to accomplish the objective of this aspect of the revised regulation and arrive, through analysis, at a site-specific ground motion that appropriately captures what is known about the seismic regime.
Using both probabilistic and deterministic evaluations to complement each other should lead to a r e stable and preitetable licensing process than in the past.
In order to implement this approach, the NRC has proposed a requirement that the annual probability of exceeding the Safe Shutdown Earthquake Ground Motion at a site be lower than the median annual probability of exceedance computed for the current population of the operating plants. This requirement assures that the design levels at new sites will be comparable to those at many existing sites, particularly more recently licensed sites.
This criterion is also used to identify significant seismic sources, in terms of magnitude and distance, affecting the estimates of ground motions at a site.
The Commission is specifically requesting comments on the questions contained in Section XI.B pertaining to the use of probabilistic seismic hazard analysis and the balance between the deterministic ~ and probabilistic evaluations. The position (s) stated in the final regulation, supporting regulatory guids and Standard Review Plan Section will-be based on Commission consideration of responses to these questions and comments on all aspects of this rulemaking.
I 24
1 4.
Safe Shutdown Earthouake. The existing regulation (10 CFR Part 100 Appendix A, Section V(a)(1)(iv)) states 'The maximum vibratory accelerations of the Safe Shutdown Earthquake at each of the various foundation locations of the nuclear power plant structures at a given site shall be determined..."
The location of the seismic input motion control point as stated in the existing regulation has led to confrontations with many applicants that believe this stipulation is inconsistent with good engineering fundamentals.
The proposed regulation would move the location of the seismic input motion control point from the foundation-level to free-field, at the free ground surface or hypothetical rock outcrop, as appropriate.
The 1975 version,
of the Standard Review Plan placed the control motion in the free-field.
The proposed regulation is also consistent with the resolution of Unresolved Safety issue (USI) A-40, " Seismic Design Criteria" (August 1989), that resulted in the revision of Standard Review Plan Sections 2.5.2, 3.7.1, 3.7.2, and 3.7.3.
However, the proposed regulation requires that at a minimum, the horizontal Safe Shutdown Earthquake Ground Motion at the foundation level of the structures must be an appropriate response spectrum with a peak ground acceleration of at least 0.19 5.
Value of the Ooeratino Basis Earthouake Ground Motion (0BE) and Reauired OBE Analysel. The existing regulation (10 CFR, Appendix A,Section V(a)(2)) states that the maximum vibratory ground motion of the OBE is one-half the maximum vibratory ground motion of the Safe Shutdown-Earthquake ground motion. Also, the existing regulation (10 CFR, Appendix A Section VI(a)(2)) states that the engineering method used to insure that structures, systems, and components are capable of withstanding the effects of the OBE l
l shall involve the use of either a suitable dynamic analysis or a suitable l
l qualification test.
In some cases, for instance piping, these multi-facets of 25
l 1
~
4 the OBE in the existing regulation made it possible for the OBE to have more design significance than the SSE.
A decoupling of the OBE and SSE has been suggested in several documents.
For instance, the NRC staff, SECY-79-300, suggested that design for a single limiting event and inspection and evaluation for earthquakes in excess of some specified limit may be the most sound regulatory approach. NUREG-1061, " Report of the U.S. Nuclear Regulatory Commission Piping Review Committee," Vol.S. April 1985, (Table 10.1) ranked a decoupling of the OBE and SSE as third out of six high priority changes.
In SECY-90-016, " Evolutionary Light Water Reactor (LWR) Certification issues and Their Relationship to Current Regulatory Requirements," the NRC staff states that it agrees that the OBE should not control the design of safety systems.
For the evolutionary reactors, the NRC will consider requests to decouple the OBE from the SSE on a design-specific basis.
Activities equivalent to OBE-SSE decoupling are also being done in foreign countries.
For instance, in Germany their new design standard requires only one design basis earthquake (equivalent to the SSE).
They require an inspection-level earthquake (for shutdown) of 0.4 S3E. This level was set so that the vibratory ground motion should not induce stresses exceeding the allowable stress limits originally required for the OBE design.
The proposed regulation would allow the value of the OBE to be set at (i) one-third or less of the SSE, where OBE requirements are satisfied without an explicit response or design analyses being performed, or (ii) a value greater than one-third of the SSE, where analysis and design are required.
There are two issues the applicant should consider in selecting the value of the OBE: first, plant shutdown is required if vibratory ground motion exceeding that of the OBE occurs (discussed below in-Item 6. Required Plant Shutdown), and second, the amount of analyses associated with the OBE.
An applicant may determine that at one-third of the SSE level, the probability of 26 L
exceeding the OBE vibratory ground.Mtion is tco high, a d the e.ost associated with plant shutdown for inspections and testing of equipment and structures prior to restarting the plant is unacceptable. Therefore, the applicant may voluntarily select an OBE value at some higher fraction of the SSE to avoid plant shutdowns.
However, if an applicant selects an OBE value at a fraction of the SSE higher than one-third, a suitable analysis shall be performed to demonstrate that the requirements associated with the OBE are satisfied. The design shall take into account soil-structure interaction effects and the expected duration of the vibratory ground motion. The requirement associated with the OBE is that all structures, systems, and components of the nuclear power plant necessary for continued operation without undue risk to the health and safety of the public shall remain functional and within applicable stress and deformation limits when subjected to the effects of the OBE in combination with normal operating loads.
As stated above, subject to further confirmation, it is deternined that if an OBE of one-third of the SSE is used, the requirements of the OBE can be satisfied without the applicant performing any explicit response analyses (some minimal design checks and the applicability of this position to seismic base isolation of buildings are discussed below). There is high confidence that, at this ground-motion level with other postulated concurrent loads, most critical structures, systems, and components will not exceed currently used design limits.
In this case, the OBE serves the function of an inspection and shutdown earthquake. There are situations associated with current analyses where only OBE is associated with the design requirements, for example, the ultimate heat sink (see Regulatory Guide 1.27, " Ultimate Heat Sink for Nuclear Powerplants").
In these situations, a value expressed as a-fraction of the SSE response would be used in the analyses.
Section Vill of this Proposed rule-identifies existing guides that would be revised technically to maintain 27
the existing design philosophy. With regard to piping analyses, positions on fatigue ratcheting and seismic anchor motion are being developed and will be issued for public coment in a draft regulatory guide separate from this rulemaking. More than one earthquake response analysis for a seismic base isolated nuclear power plant design may be necessary tn ensure adequate performance at all earthquake levels. Decisions pertaining to the response analyses associated with base isolated facilities will be handled on a case by case basis.
6.
Reouired Plant Shutdown.
The current regulation (Section V(a)(2))
states that if vibratory ground motion exceeding that of the OBE occurs, shutdown of the nuclear power plant is required.
The supplementary information to the final regulation (published November 13, 1973, 38 FR 31279, item 6e) includes the following statement: "A footnote has been added to 550.36(c)(2) of 10 CFR Part 50 to assure that each power plant is aware of the limiting condition of operation which is imposed under Section V(2) of Appendix A to 10 CFR Part 100.
This limitation requires that if vibratory ground motion exceeding that of the OBE occurs, shutdown of the _ nuclear power plant will be required.
Prior to resuming operations, the licensee will be required to demonstrate to the Comission that no functional damage has occurred to those features necessary for continued operation without undue risk to the health and safety of the public." At that time, it was the intention of the Comission to treat the Operating Basis Earthqucke as a limiting condition of operation.
From the statement in the Supplementary Information, the Comission directed applicants to specifically review 10 CFR Part 100 to be aware of this intention in complying with the requirements of 10 CFR 50.36.
Thus, the requirement to shut down if an OBE occurs was expected to be implemented by being included among the technical 28
specifications submitted by applicants after the adoption of Appendix A.
In fact, applicants did not include OBE shutdown requirements in their technical specifications.
The proposed regulation would treat plant shutdown associated with vibratory ground motion exceeding the OBE or significant plant damage as a condition in every operating license.
The shutdown requirement would be a condition of the license (10 CFR 50.54) rather than a limiting condition of operation (10 CFR 50.36), because the necessary judgments associated with exceedance of the vibratory ground motion or significant plant damage can not be adequately characterized in a technical specification.
A new paragraph 550.54(ee) would be added to the -regulations to require plant shut down for licensees of nuclear power plants that comply with the earthquake engineering criteria in Paragraph IV(a)(3) of Proposed Appendix S, " Earthquake Engineering Criteria for Nuclear Power Plants," to 10 CFR Part 50.
Draft Regulttory Guide DG-1017, ' Pre-Earthquake Planning and immediate Nuclear Power Plant Operator Post-Earthquake Actions,' is being developed to provide guidance acceptable to the NRC staff for determining whether or not vibratory ground motion exceeding the OBE ground motion or significant plant damage had occurred and nuclear power plant shut down is required. The guidance is based on criteria developed by the Electric Power Research Institute (EPRI). The decision to shut down the-plant should be made within eight hours after the earthquake. The data from the seismic instrumentation, coupled with information obtained from a plant walkdown, are used to make the determination of whether the plant should be shut down, if it has not already been shut down by operational perturbations resulting from the seismic event.
The guidance being developed in Draft Regulatory Guide DG-1017 is based on two assumptions, first, that the nuclear power plant has operable seismic instrumentation, including the equipment and software required to process the 29
4 4
data within four hours after an earthquake, and second, that the operator walkdown inspections can be performed in approximately four to eight hours depending on the number of personnel conducting the inspection.
If vibratory ground motion exceeding that of the Operating Basis Earthquake Ground Motion or if significant plant damage occurs, the licensee must shut down the nuclear-power plant.
If the licensee determines that plant shutdown is required by the Commission's regulations, but the licensee does not think it prudent to do so, the licensee may ask for an emergency exemption from the requirements of f
the regulation pursuant to Section 50.12 to 10 CFR Part 50 so that the plant need not shut down if the exemption is granted.
Draft Regulatory Guide DG-1018, " Restart of a Nuclear Power Plant Shut Down by a Seismic Event," is being developed to provide guidelines that are acceptable to the NRC staff for performing inspections and tests of nuclear power plant equipment and structures prior to plant restart.
This guidance is also based on EPRI reports.
Prior to resuming operations, the licensee must demonstrate to the Commission that no functional damage has occurred to those features necessary for continued operation without undue risk to the health and safety of the public.
The results of post-shutdown inspections, operability checks, and surveillance tests shall be documented in written reports and submitted to the Director, Office of Nuclear Reactor Regulation.
The licensee shall not resume operation until authorized to do so by the Director, Office of Nuclear Reactor Regulation.
l l
7.
Clarify Interoretations.
In Appendix B to 10 CFR Part 100, changes have been made to resolvo questions of interpretation. As an example,.
definitions and required investigations stated in the proposed regulation would be significantly changed to eliminate or modify phrases that were more applicable to only the western part of the United States.
30
l j
VI. Siting Policy Task Force Recomendations The Siting Policy Task Force made nine recomendations with regard to revision of the reactor siting criteria in NUREG-0625, " Report of the $iting Policy Task Force," August 1979.
The individual recomendations and the proposed disposition and actions being taken in regard to each of these are discussed below.
Recomendation 1.
Revise Part 100 to change the way protection is provided for accidents by incorporating a fixed exclusion area and protection action distance and population density and distribution criteria.
1.
Specify a fixed minimum exclusion distance based on limiting the individual risk from design basis accidents.
Furthermore, the regulations should clarify the required control by the utility over activities taking place in land and water portions of the exclusion area.
2.
Specify a fixed minimum emergency planning distance of 10 miles.
The physical characteristics of the emergency planning zone should provide reasonable assurance that evacuation of persons, it:cluding transients, would be feasible if needed to mitigate the consequences of accidents.
3.
Incorporate specific population density and distribution limits outside the exclusion area that are dependent on the average population of the region.
4.
Remove the requirement to calculate radiation doses as a means of establishing minimum exclusion distances and low population zones.
Disposition and Action.
Recomendation I has been or is largely proposed to be adopted by the-Comission. With regard to item 1, a fixed minimum exclusion area distance of 31 L
i 0.4 mile, comensurate with past NRC experience in the review of design basis accidents, is being proposed. The Comission believes that the existing requirements regarding control over any land portion of the exclusion area together with current emergency planning requirements make any new requirements on exclusion area control unnecessary.
The recomendations in item 2 were adopted by the Comission shortly after the Three Mile Island accident and are contained in 10 CFR 50.47. The recomendations in item 3 are proposed to be adopted except that the population density and distribution limits are proposed to be applicable nationwide.
The recomendation of item 4 is proposed to be adopted.
Recomehrjation 2.
Revise 10 CFR Part 100 to require consideration of the potential hazards-posed by man-made activities and natural characteristics of sites by establishing minimum standoff distances for:
- 1. Major or comercial airports,
- 2. Liquid Natural Gas (LNG) terminals,
- 3. Large propane pipelines,
- 4. Large natural gas pipelines,
- 5. Large quantities of explosive or toxic materials, 6.Majordams,and
- 7. Capable faults.
Q11pnition and Action.
Recomendation 2 is proposed to be adopted in part and rejected in part.
10 CFR Part 100 is to be revised to include consideration of man-related hazards. However, establishing minimum standoff distances by regulation for the hazards cited is not feasible.
NRC review has found that acceptable separation distances are not readily quantified and can depend upon many other 32
factors such as the topography, size, and operational aspects of the facilities, in addition to the distance from the reactor.
Accordingly, the proposed regulation will require that the hazards be identified and evaluated so that they can be adequately considered in the design of the reactor to be located on the site.
Present NRC review criteria, as given in the Standard Review Plan (SRP), Section 2.2.3, are considered adequate.
Recommendation 1 Revise 10 CFR Part 100 by requiring a reasonable assurance that interdictive measures are possible to limit groundwater contamination resulting from Class 9 accidents within the immediate vicinity of the site.
Discosition and Action.
The Commission is not proposing to adopt this recommendation.
- However, requirements on future reactor designs will address the need to consider and minimize containment failure under severe accident conditions.
Future reactor designs will need to address the potential for ground water contamination as part of their environmental review under 10 CFR Part 51.
Recommendation 4 Revise Appendix A to 10 CFR Part 100 to better reflect the evolving technology in assessing seismic hazards.
Disposition and Action.
The Commission is proposing to adopt this recommendation in this rulemaking.
Recommendation 5.
Revise 10 CFR Part 100 to include consideration of post-licensing l
changes in offsite activities.
'33 l
1.
The NRC staff shall inform local authorities (planning comission, county comissions, etc.) that control activities within the emergency planning zone (EPZ) of the basis for determining the acceptability of a site.
2.
The NRC staff shall notify those Federal agencies as in item 1 above that may reasonably initiate a future Federal action that may influence the nuclear power plant.
3.
The NRC staff shall require applicants to monitor and report potentially adverse offsite developments.
4.
If, in spite of the actions described in items 1 through 3, there are offsite developments that have the potential for significantly inert;asing the risk to the public, the NRC staff will consider restrictions on a case-by-case basis.
Disoosition and Action.
This recomendation is already in effect or is proposed to be adopted.
Item 1 is already covered by existing emergency planning requirements.
Item 2 is being accomplished by issuance of a Significant Hazard Consideration statement by the NRC staff. The Comission is requesting coments on item 3.
With regard to item 4, the Comission retains the right to order restrictions on a case-by-<ase basis.
Recommendation 6.
Continue the current approach relative to site selection from a safety viewnoint, but select sites so that there are no unfavorable characteristics requiring unique or unusual design to compensate for site inadequacies.
Disoosition and Action.
The Comission is not proposing to adopt this recomendation.- In'the current and proposed Part 100 regulations, applicants may provide specific plant design features to compensate for site inadequacies.
As-long as these 34
design features adequately account for the conditions at the site, pubite health and safety will be protected. These specific design features may involve added costs.
However, the Commission has concluded that any economic consideration should be left to the applicant.
Reconmendation 7.
Revise Part 10f' to specify that site approval-be established at the earliest decision point in the review and to provide criteria that would have to be satisfied for this approach to be subsequently reopened in the licensing process.
Discosition and Action.
The Commission considers that the early site permit provisions of 10 CFR Part 52 accomplish this recommendation.
Recommendation 8 Revise 10 CFR Part 51 to provide that a final decision disapproving a proposed site by a state agency whose approval is fundamental to the project would be a sufficient basis for NRC to terminate review, lhe termination of a review would then be reviewed by the Commission.
Disposition and Action.
The Commission is not proposing to adopt this recommendation because it is considered inappropriate. This recommendation would give a State the authority to grant issuance of a construction permit for a nuclear facility.
Only the Federal government has this authority.- States do have an independent right to deny site approval as long as it is not a radiological health and safety, common defense, or security concern, 4
35
Recommendation 9.
Develop comon bases fo ' comparing the risks for all external events.
Disoosition and Action.
The Siting Policy Task Force's primary recomendation in this area was that an interdisciplinary effort should be undertaken with'the objective of developing quantitative risk comparisons of all external events and natural phenomena. The Comission considers this to be a desirable objective but notes that the Siting Policy Task Force made no specific recomendations with regard to siting criteria or rulemaking. The Comission therefore considers this recomendation inapplicable in the present context of examination of siting criteria, but notes that recent developments in probabilistic risk-analysis (PRA) have considered examination of tha risk from external events in detail.
VII.
Related Regulatory Guides and Standard Review Plan Section The NRC is developing the following draft regulatory guides and standard review plan section to provide prospective licensees with the necessary guidance for implementing the proposed regulation. The notice of availability for these materials is published elsewhere in this issue of the Federal
- Register,
- 1. DG-1015, ' Identification and Characterization of Seismic Sources, Deterministic Source Earthquakes, and Ground Motion."
The draft guide provides general guidance and recomendations, describes acceptable procedures and provides a list of references that present acceptable methodologies to identify and characterize capable tectonic sources and seismogenic sources.
- 2. DG-1016, Second Proposed Revision 2 to Regulatory Guide 1.12,
' Nuclear Power Plant Instrumentation for Earthquakes."
The draft guide 36
i descrioes seismic instrumentation type and location, operability, characteristics, installation, actuation, and maintenance that are acceptable to the NRC staff.
- 3. OG-1017, ' Pre-Earthquake Planning and Imediate Nuclear Power Plant Operator Post-Earthquake Actions.'
The draft guide provides guidelines that are acceptable to the NRC staff for a timely evaluation of the recorded seismic instrumentation data and to determine whether or not plant shutdown is required.
- 4. DG-1018, ' Restart of a Nuclear Power Plant Shut Down by a Seismic Event.'
The draf t guide provides guicelines that are acceptable to the NRC staff for performing inspections and tests of nuclear power plant equipment and structures prior to restart of a plant that has been shut down because of a seismic event.
- 5. Draf t Standard Review Plan Section 2.5.2, Proposed Revision 3
' Vibratory' Ground Motion.'
The draft describes procedures to assess the ground motion potential of seismic sources at the site and to assess the adequacy of the SSE.
- 6. Draft Regulatory Guide 4.7, Revision 2, dated December 1991, " General Site Suitability Criteria for Nuclear Power Plants."
This guide discusses the major site characteristics related to public liealth and safety and environmental issues that the NRC staff considers in determining the suitability of sites.
VIII.
Future Regulatory Action Several existing regulatory guides will be revised to incorporate editorial changes or maintain the existing design or analysis philosophy.
These guides will be issued to coincide with the publication of the final 37
)
regulations that would implement this proposed action.
The following regulatory guides will be revised to incorporate editorial changes, for example to referer.ce new paragraphs in Appendix B to Part 100 or Appendix S to Part 50.
No technical changes will be made in these regulatory guides.
1.
1.57, " Design Limits and Loading Combinations for Metal Primary Reactor Containment System Components."
2.
1.59, " Design '8 asis Floods for Nuclear Power P' ants."
3.
1.60, ' Design Response Spectra for Seismic Design of Nuclear Power Plants."
4.
1.83, " Inservice Inspection of Pressurized Water Reactor Steam Generator Tubes."
5.
1.92, ' Combining Modal Responses and Spatial Components in Seismic Response Analysis."
6.
1.102, " Flood Protection for Nuclear Power Plants."
7.
1.121, " Bases for Plugging Degraded PWR Steam Generator Tubes "
8.
1.122, " Development of Floor Design Response Spectra for Seismic Design of Floor-Supported Equipment or Components."
The following regulatory guides will be revised to update the design or analysis philosophy, for example, to change OBE to a fraction of the SSE:
1.
1.27, " Ultimate Heat Sink for Nuclear Power Plants' 2.
1.100, " Seismic Qualification of Electric and Mechanical Equipment for Nuclear Power Plants' 3.
1.124, ' Service Limits and Loading Combinations for Class 1 38 l
l
t Linear-Type Component Supports
- 4.
1.130, " Service Limits and Loading Combinations for Class 1 Plate-and-Shell-Type Component Supports' 5.
1.132, ' Site Investigations for Foundations of Nuclear Power Plants
- 6.
1.138, ' Laboratory Investigations of Soils for Engineering Analysis and Design of Nuclear Power Plants' 7.
1.142, ' Safety-Related Concrete Structures for Nuclear Power Plants (Other than Reactor Vessels and Containments)"
8.
1.143, ' Design Guidance for Radioactive Waste Management Systems, Structures, and Components Installed in Light-Water-Cooled Nuclear Power Plants' Minor and conforming changes to other Regulatory Guides-and standard review plan sections as a result of proposed changes in the nonseismic criteria are also planned.
If substantive enanges are made during the revisions, the applicable guides will be iss.ied for public coment as draft guides.
IX. Referenced Documents An interested person may examine or obtain copies of the documents referenced in this proposed rule as set out below.
Copies of NUREG-0625, NUREG-1150, and NUREG/CR-2239 may be purchased from the Superintendent of Documents, U.S. Government Printing Office, P.O.
Box 37082, Washington, DC 20013-7082.
Copies are also available from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161.
A copy is also available for inspection and copying for a fee in the 39
9 NRC Public Document Room, 2120 L Street, NW. (Lower Level), Washington, DC.
Copies of issued regulatory guides may be purchased from the Government Printing Office (GPO) at the current GP0 price.
Information on current GPO prices may be obtained by contacting the Superintendent of_ Documents, U.S.
Government Printing Office, P.O. Box 37082, Washington, DC' 20013-2171.
Issued guides may also be purchased from the National Technical Information Service on a standing order basis.
Details on this service may be obtained by writing NTIS, 5826 Port Royal Road, Springfield, VA 22161.
SECY 79-300, SECY 90-016, and WASH-1400 are available for inspection and copying for a fee at the Comission's Fublic Document Room, 2120 L Street, NW. (Lower Level), Washington, DC..
X.
Submission of Coments in Electronic Format The coment process will be improved if each coment is identified with the document title, section heading, and paragraph number addressed.
Comenters are encouraged to submit, in addition to the original paper copy, a copy of the letter in electronic format on 5.25 or 3.5 inch computer diskette; IBM PC/ DOS or HS/ DOS format. Data files should be provided in one of the following formats: Wordperfect IBM Document Content Architecture / Revisable-Form-Text (DCA/RFT), or unformatted ASCII code.
The format and version should be identified on the diskette's external label.
XI. Questions In addition to soliciting coments on all aspects of this rulemaking, the Comission specifically requests coments on the following questions.
40
)
A.
Reactor Siting Criteria (Nonseismic).
e 1.
Should the Commission grandfather existing reactor sites-having an exclusion area distance less than 0.4 miles (640 meters) for the possible placement of additional units, if those sites are found suitable from safety considerations?
2.
Should the exclusion area distance be smaller than 0.4 mile (640 meters) for plants having reactor power levels significantly less than 3800 Megawatts (thermal) and should the exclusion area distance be allowed to vary according to power level with a minimum value (for example, 0.25 miles or 400 meters)?
3.
The Commission proposes to codify the population density guidelines in Regulatory Guide 4.7 which states that the population density should not exceed 500 people per square mile out to a distance of 30 miles 2t the time of site approval and 1000 people-per square mile 40 years thereafter.
Comments are specifically requested on questions 3A, 3B, and 3C given below.
A. Should numerical values of population density appear in the regulation or should the regulation provide merely general guidance, with I
numerical values provided in a regulatory guide?
B. Assuming numerical values are to be codified, are the values of -
500 persons per square mile at the time of site approval and 1000 persons-per square mile 40 years thereafter appropriate? If not, what other numerical values should be codified and what is the basis for these values?
41 l
4 C. Should population density criteria be specified out to a distance other than 30 miles (50 km), for example, 20 miles (32 km)? If a different distance is recomended, what is its basis?
4.
Should the Comission approve sites that exceed the proposed population values of'10 CFR Part 100.21, and if so, under what conditions?
5.
Should holders of early site permits, construction permits, and operating license permits be required to periodically report changes in potential offsite hazards-(for example, every 5 years within 5 miles)?
If so, what regulatory purpose would such reporting requirements serve?
6.
What continuing regulatory significance should the safety requirements in 10 CFR Part 100 have after granting the initial operating license or combined operating license under 10 CFR Part 527 7.
Are there certain site meteorological conditions that should preclude the siting of a nuclear power plant? If so, what are the conditions that can not be adequately compensated for by design features?
8.
In the description of the disposition of the recomendations of the Siting Policy Task Force report (NUREG-0625), it was noted that the Comission was not adopting every element of each recomendation. Are there compelling reasons to reconsider any recomendation not adopted and, if.so, what are the bases for reconsideration?
B.
Seismic and Earthquake Engineering Criteria.
42
\\;
4 4
-The proposed guide, DG-1015, outlines concepts and procedures-to.be used in conjunction with the probabilistic/ deterministic seismic hazard evaluations.
Rationale for the approach is discussed in Section V.B(3) of this Proposed rule.
The staff is currently performing confirmatory studies to evaluate and refine these proposed procedures.
A limited study has been completed demonstrating the feasibility of procedures and the validity of the concepts.
However, the staff would like to solicit comments on the concepts outlined in the proposed guide at this time. To facilitate the review, results of the.
application of the proposed procedure to four test sites are published separately (letter report from D. Bernreuter of LLNL to A. Murphy of NRC dated September 24, 1992, available in the NRC Public Document Room at 2120 L Street NW, (Lower Level), Washington, DC.).
There are divergent views on the role probabilistic seismic hazard analysis should play in the licensing arena. There is a general consensus within the NRC staff that the revised seismic and geological siting criteria should allow considerations for a probabilistic hazard analysis. There is also a general belief that the outcome of a probabilistic analysis should be compared with the results of past practices for siting and licensing the current generation of nuclear power plants.
There is a general consensus that ground motions should be calculated using deterministic methods once the controlling earthquakes are determined. With regard to the role of the probabilistic annlysis, views range from an advocacy of a predominantly probabilistic analysis to the probabilistic/ deterministic proposed here to a predominantly deterministic approach as used currently.
Given these divergent views, the NRC staff would like to invite comments regarding the use of probabilistic seismic hazard analysis and the balance between the deterministic and probabilistic evaluations. This and other associated issues 43
4 are itemized below.
(As the detailed technical studies are completed some of the staff positions may be confirmed, but specific comments would be helpful at this time.)
1.
In making use of both deterministic and probabilistic evaluations, how should they be combined or weighted, that is, should one dominate over the other?
(The NRC staff feels strongly that deterministic investigation and their use in the development and evaluation of the Safe Shutdown Earthquake Ground Motion should remain an important aspect of the siting regulations for nuclear power plants for the foreseeable future.
The NRC staff also feels that probabilistic seismic hazard assessment methodologies have reached a level of maturity to warrant a specific role in siting regulations.)
2.
In making use of the probabilistic and deterministic evaluations as proposed in Draft Regulatory-Guide DG-1015, is the proposed procedures in Appendix C to DG-1015, adequate to determine controlling earthquakes from the probabilistic analysis?
3.
In determining the controlling earthquakes, should the median values of the seismic hazard analysis, as described in Appendix C to Draft Regulatory Guide DG-1015, be used to the exclusion of other statistical measures,such as, mean or 85th percentile? (The staff has selected probability of exceedance levels associated with the median hazard analysis estimates as they provide more stable estimates of controlling earthquakes.)
44
- 4. -
_The proposed Appendix B to 10 CFR Part 100 has included in-Paragraph V(c) a criterion that states: "The annual probability of exceeding the Safe Shutdown Earthquake Ground Motion is considered 1
acceptably low if it is less than the median annual probability computed from the current (EFFECTIVE DATE OF Tile REGULATION) population of nuclear power plants." This is a relative criterion without any specific numerical value of the annual probability of-exceedance because of the current status of the probabilistic seismic hazard analysis.
However, this requirement assures that the design levels at new sites will be comparable to those at many existing sites, particularly more recently licensed sites. Method dependent annual probabilities or target levels (e.g.,1E-4 for LLNL or 3E-5 for EPRI) are identified in the proposed regulatory guide. Sensitivity studies addressing the effects of different target probabilities are discussed in the Bernreuter to Murphy letter report. Comments are solicited as.to: (a) whether the above criterion, as stated, needs to be included in the regulation? and, (b) if not, should it be included in the regulation in a different form (e.g., a specific numerical value, a level other than the median annual probability computed for the current plants)?
5.
For the probabilistic analysis, how many controlling earthquakes should be generated to cover the frequency band'of concern for-nuclear power plants?
(For the four trial plants used to develop the criteria presented in Draft Regulatory Guide DG-1015, the average of results for the 5 Hz and 10 Hz spectral velocities was used to establish the probability of exceedance level. Controlling 45
l earthquakes were evaluated for this frequency band, for the average of I and 2.5 Hz spectral responses, and for peak ground acceleration.)
Xil.
Finding of No Significant Environmental Impact: Availability The Commission has determined under the National Environmental Policy Act of 1969, as amended, and the Comission's regulations in Subpart A of 10 CFR Part 51, that this proposed regulation, if-adopted, would not be a major Federal action significantly affecting the quality of the human environment and therefore an environmental impact statement is not required.
The revisions associated with the reactor siting criteria in 10 CFR Part 100 and the relocation of the plant design requirements from 10 CFR Part 100 to 10 CFR Part 50 have been evaluated against the current requirements. 'The Commission has concluded that relocating the requirement for a dose calculation to Part 50 and adding more specific site criteria to Part 100 does not decrease the protection of the public health and safety over the current regulations. The proposed amendments do not affect nonradiological plant effluents and have no other environmental impact.
The addition of Appendix B to 10 CFR Part 100, and the addition of Appendix S to 10 CFR Part 50, will not change the radiological environmental impact offsite.
Onsite occupational radiation exposure associated with inspection and maintenance will not change. These activities are principally associated with base line inspections of structures, equipment, and piping, and with maintenance of seismic instrumentation.
Base line inspections are needed to differentiate between pre-existing conditions at the nuclear power plant and earthquake related damage.
The structures, equipment and piping selected for these inspections are those routinely examined by plant operators 46
)
1
n during normal plant walkdowns and inspections.
Routine maintenance of seismic instrumentation ensures its operability during earthquakes. The location of the seismic instrumentation is similar to that in the existing nuclear power plants. The proposed amendments do not affect nonradiological plant effluents and have no other environmental impact.
The environmental assessment and finding of no signifit. ant impact on which this determination is based are available for inspection at the NRC Public Document Room, 2120 L Street NW. (Lower Level), Washington, DC.
Single copies of the environmental assessment and finding of no significant impact are available from Mr. Leonard Soffer, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555, telephone (301) 492-3916, or Dr. Andrew Murphy, Office of Nuclear Regulatory Research, U.S.
Nuclear Regulatory Commission, Washington, DC 20555, telephone (301) 492-3860, XIII. Paperwork Reduction Act Statement This proposed regulation amends information collection requirements-that are subject to the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.).
This proposed regulation has been submitted to the Office of Management and Budget for review and approval of the paperwork requirements.
There is no public reporting burden related to the nonseismic siting criteria. Public reporting burden for the collection of information related to the seismic and earthquake engineering criteria is estimated to average 800,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information.
Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to 47
the -Information and Records Management Branch (MNBB 7714), U.S. Nuclear Regulatory Commission, Washington, DC 20555; and to the Desk Officer, Office of Information and Regulatory Affairs, NE0B-3019, (3150-0011 and 3150-0093),
Office of Manageraent and Budget Washington, DC 20503.
4 XIV.
Regulatory Analysis The Commission has prepared a draft regulatory analysis on this proposed regulation. The analysis examines the costs and benefits of the alternatives considered by the Commission.
Ti.e draft analysis is available for inspection in the NRC Public Document Room, 2120 L Street NW. (Lower Level), Washington, DC.
Single copies of the analysis are available from Mr. Leonard Soffer, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555, telephone (301) 492-3916, or Dr. Andrew J.'Hurphy, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555, telephone (301) 492-3860.
The Commission requests public comment on the draft regulatory analysis.
Comments on the draft analysis may be submitted to the NRC as indicated under the ADDRESSES heading.
XV.
Regulatory Flexibility Certification In accordance with the Regulatory Flexibility Act of.1980 (5 U.S.C.
605(b)), the Commission certifies that this proposed regulation will not, i.
promulgated, have a significant economic impact on a substantial number of small entities. This proposed regulation affects only the licensing and operation of nuclear power plants. Nuclear power. plant site applicants do not fall within the definition of small businesses as defined in Section 3 of the 48
Small Business Act (15 U.S.C. 632), the Small Business Size Standards of the-Small Business Administrator (13 CFR Part 121), or the Comission's Size Standards (56 FR 56671; November 6, 1991).
XVI.
Backfit Analysis Ine NRC has determined that the backfit rule, 10 CFR 50.109, does not apply to this proposed regulation, and therefore, a backfit analysis is not
(
required for this proposed regulation because these amendments do not involve any provisions that would impose backfits as defined in 10 CFR 50.109(a)(1).
The proposed regulation would apply only to applicants for future nuclear power plant construction permits, preliminary design approval, final design approval, manufacturing licenses, early site reviews, operating licenses, and combined operating licenses.
List of Subjects 10 CFR Part 50 - Antitrust, Classified information, Criminal penalty, Fire protection Incorporation by reference, Intergovernmental relations, Nuclear power plants and reactors, Radiation protection, Reactor siting criteria, Reporting and recordkeeping requirements.
10 CFR Part 52 - Administrative practice and procedure, Antitrust, Backfitting, Combined license, Early site permit, Emergency planning, Fees, Inspection, Limited work authorization, Nuclear power plants and reactors, Probabilistic risk assessment, Prototype, Reactor siting criteria, Redress of.
site, Reporting and recordkeeping requirements, Standard design, Standard design certification.
49
~_
10 CFR.Part 100 - Nuclear power plants and reactors, Reactor siting criteria.
For the reasons set out in the preamble and'under the authority of the Atomic Energy Act of 1954, as amended, the Energy Reorganization Act of 1974, as amended, and 5 U.S.C. 553, the NRC is propo:ing to adopt the following amendments to 10 CFR Parts 50, 52 and 100.
PART 50 - DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION FACILITIE'J 1.
The authority citation for Part 50 continues to read as follows:
AUTHORITY:
Secs, 102, 103, 104, 105, 161, 182, 183, 186, 189, 68 Stat.
936, 937, 938, 948, 953, 954, 955, 956, as amended, sec. 234, 83 Stat. 1244, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201, 2232, 2233, 2236, 2239, 2282); secs. 201, as amended. 202, 206, 88 Stat. 1242, as amended, 1244, 1246, (42 U.S.C. 5841, 5842, 5846).
Section 50.7 also issued under Pub. L.95-601,_ sec.10, 92 Stat. "oS1 (42 U.S.C. 5851).
Section 50.10 also issued under secs. 101, ISS, 68 Stat.
936, 955 as amended (42 U.S.C. 2131, 2235), sec. 102, Pub. L.91-190, 83 Stat.
853 (42 U.S.C. 4332).
Sections 50.13, 50.54(dd) and 50.103 also issued under sec. 108, 68 Stat. 939,-as amended (42 U.S.C. 2138).
Sections-50.23, 50.35, 50.55, and 50.56 also issued under sec. 185, 68 Stat. 955 (42 U.S.C.-2235).
Sections 50.33a, 50.55a and Appendix Q also issued under sec. 102, Pub. L.91-190, 83 Stat. 853 (42 U.S.C. 4332).
Sections 50.34 and 50.54 also issued under sec. 204, 88 Stat. 1245 (42 U.S.C. 5844).
Sections 50.58, 50.91 and 50.92 also issued under Pub. L.97-415, 96 Stat. 2073 (42 U.S.C.-2239).
50
Section 50.78 also issued under sec. 122, 68 Stat 939 (42 U.S.C. 2152).
Sections 50.80 - 50.81 also issued under sec. 184, 68 Stat. 954, as amended (42 U.S.C. 2234).
Appendix F also issued under sec.187, 68 Stat. 955 (42 U.S.C. 2237).
For the purposes of sec. 223, 68 Stat. 958, as amendsd (42 U.S.C. 2273),
SS 50.5, 50.46(a) and (b), and 50.54(c) are issued under sec.161b, 68 Stat.
948, as amended (42 U.S.C. 2201(b)); 55 50.5, 50.7(a), 50.10(a)-(c), 50.34(a) and (e), 50.44(a)-(c), 50.46(s) and (b), 50.47(b), 50.48(a), (c), (d), and (e), 50.49(a), 50.54(a)(1), (i)(1), (1)-(n), (p), (q), (t), (v), and (y),
50.55(f), 50.55a(a), (c)-(e), (g), and (h), 50.59(c), 50.60(a), 50.62(b),
50.64(b), 50.65 and 50.80(a) and (b) are issued under sec. 1611, 68 Stat. 949, as amended (42 U.S.C. 2201(1)); and 5550.49(d), (h), and (j), 50.54(w), (z),
(bb), (cc), and (dd), 50.55(e), 50.59(b), 50.61(b), 50.62(b), 50.70(a),
50.71(a)-(c) and (e), 50.72(a), 50.73(a) and (b), 50.74, 50.78, and 50.90 are issued under sec. 1610, 68 Stat. 950, as amended (42 U.S.C. 2201(o)).
2.
In 550.2, add the definitions for exclusion area, low population zone, and population center distance to read as follows:
5 50.2 Definitions.
As used in this part.
Exclusion area means that area surrounding the reactor, in which the reactor licensee has the authority to determine all activities including exclusion or removal of personnel' and property from the area.
This area may be traversed by a highway, railroad, or waterway, provided these are not so close to the facility as to interfere with normal operations of the facility and provided appropriate and effective arrangements are made to control traffic on the highway, railroad, er waterway, in case of emergency, to 51
protect the public health and safety.
Residence within the c4clusion area shall normally be prohibited.
In any event, residents shall be subject to ready removal in case of necessity. Activities unrelated to operation of the reactor may be permitted in an exclusion area under appropriate limitations, provided that no significant hazards to the public health and safety will result.
Low oooulation zone means the area immediately surrounding the exclusion area which contain residents, the total number and density of which are such that there is a reasonable probability that appropriate protective measures could be taken in their behalf in the event of a serious accident.
These guides do not specify a permissible population density of total population within this zone because the situation may vary from case to case.
Whether a specific number of people can, for example, be evacuated from a specific area, or instructed to take shelter, on a timely basis will depend on many factors such as location, number and size of highways, scope and extent of advance planning, and actual distribution of residents within the area.
Pooulation center distance means the distance from the reactor to the nearest boundary of a densely populated center containing more then 25,000 residents.
3.
In 550.8, paragraph (b) is revised to read as follows:
550.8 Information collection requirements: OMB approval.
(b)
The approved information collection requirements contained in this part appear in 50.30, 50.33, 50.33a, 50.34, 50.34a, 50.35, 50.36, 50.36a, 50.48, 50.49, 50.54, 50.55, 50.55a, 50.59, 50.60, 50.61, 50.63, 50.64, 50.65, 50.71, 50.72, 50.80, 50.82, 50.90, 50.91, and Appendices A, B, E, G, H, I, J, 52
K, H. N, 0, Q R, and S.
4.
In 550.34, footnotes 6, 7, and 8 are redesignated as footnotes 8, 9 and 10, paragraph (a)(1) is revised and paragraphs (a)(12) and ~(b)(10) are added to read as follows:
5 50.34 Contents of applications; technical information.
(a)
(1)
A description and safety assessment of the site and a safety assessment of the facility.
Site characteristics must comply with Part 100 of this chapter. Special attention must be directed to plant i ign features intended to mitigate the radiological consequences of accidents. In performing this assessment, an applicant shall assume a fission product release' from the core into the containment assuming that the facility is operated at the ultimate power level contemplated. The applicant shall perform an evaluation and analysis of the postulated fission product release, using the expected demonstrable containment leak rate and any fission product cleanup' systems intended to mitigate the-consequences of the accidents, together with applicable site characteristics, including site meteorology, to evaluate the offsite radiological consequences. The evaluation must determine that:
(i)
An individual located at any point on the boundary of the exclusion area for two hours immediately folle:ing the onset of the postulated
- The fission product release assumed for this evaluation should be based upon a major accident.
hypothesized or detenntned frcin considerations of possible accidental evr.ts that would result in potential hazards not exceeded by those from any accident considered credible. Such accidents have generally been assumed to result in substanttal meltdown of the core with subsequent release into the containment of appreciable cuantitles of fission products, 53
fission product release would not receive a total radiation dose to.the whole body in excess of 25 rem' or a total radiation dose in excess of 300 rem' to -
the thyroid from iodine exposure.
(ii) An individual located at any point on the outer radius of a low population zone who _is exposed to the radioactive cloud resulting from-the ~
postulated fission product release (during the entire period of its passage) would not receive a total radiation dose to the whole body in excess of 25 rem r
or a total radiation dose it. excess of 300 rem to the thyroid from iodine --
exposure.
For purposes of this evaluation, a low population zone bounda'ry of 3.0 miles (measured from the reactor center point) is assumed.
(iii) Vith respect to operation at the projected initial power level, the applicant is required to submit information prescribed in paragraphs (a)(2) through (a)(8) of this section, as well as the information-required by this paragraph, in support of the application for a construction permit.
NOTE: Reference is made to Technical Information Document (TID) 14844, dated March 23, 1962, which contains a fission product release into~ containment which has been used in past evaluations. The fission product release given-in:
L TID-14844 may be used as a point of departure upon consideration of severe accident research insights available since its issuance, upon consideration.of l'
' The whole body dose of 25 rem referred to above has been stated to correspond nwnerically to the once in a lifetime accidental or emergency does for radiation workers which. according to NCRP reconenendations may be disregarded in the determinattnn of their radiation exposure status (see NBS Hanobook 69 dated June 5.1959),
fore recently, this whole body dose value has also been provided as guidance for radistion workers performing emergency services involving life saving activities or protection of large populations where lower cosos are not practicable (see EPA, Manual of Protective Action Guides and Protective Actions.for Nuclear' Incidents.
Draft, September 1990). However, neither its use nor that of the 300 rem value for thyroid exposure as set forth in this section are intended to toply that these nuncers constitute acceptable limits for emergency coses -
to the public under accioent conditions, Rather, this 25 rem whole body value' and the 300 rem thyroid value -
have been set forth in this section as reference values, which can be used in the evaluation of plant design features with respect to postulated reactor accidents, in order to assure that such designs provide assurance :
of low risk of public exposure to radiation, in the event of such accidents.
54 l.
.a
plant design features intended to mitigate the consequences of accidents, or upon characteristics of a particular reactor. Copies of Technical Information Document 14844 may be obtained from the Commission's Public Document Room, 2120 L Street, NW. (Lower Level), Washington, DC., or by writing the Director of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Coninission, Washington, DC. 20555.
(12) On or after (EFFECTIVE DATE OF THIS REGULATION), applicants who apply for a construction permit pursuant to this part, or a design certification or combined license pursuant to Part 52 of this chapter, as partial conformance to General Design Criterion 2 of Appendix A to this part, shall comply with the earthquake engineering criteria in Appendix S of this part.
(b)
(10) On or after (EFFECTIVE DATE OF THIS REGULATION], applicants who apply for an operating license pursuant to this part, or a design certification or combined license pursuant to Part 52 of this chapter, as -
partial conformance to General Design Criterion 2 of Appendix A to this part, shall comply with the earthquake engineering criteria of Appendix S to this l
part. However, if the construction permit was issued prior to (EFFECTIVE DATE OF THIS REGULATION), the applicant shall comply with the earthquake l
engineering criteria in Section VI cf Appendix A to Part 100_of this chapter.
5.
In C % paragraph (ee) is added to read as follows:
55 L
4 550.54. Conditions _of licenses.
i; e-(ee) For licensees of nuclear power plants that have _ implemented the earthquake engineering criteria in Appendix S of'this part, plant shutdown is required if the criteria in Paragraph IV(a)(3) of Appendix S are exceeded.
Prior-to resuming operations, the licensee shall demonstrate to the Commission that no-functional damage-has occurred to those features necessary for continued operation without undue risk to the health and safety of the public.
6.
Appendix S to Part 50 is added to read as.follows:
APPENDIX S TO PART 50 - EARTHQUAKE ENGINEERING CRITERIA FOR NUCLEAR POWER PLANTS-General Information This appendix _ applies to applicants who apply for a design ceEtification or combined license pursuantEto Part-52 of this chapter or'a construction permit or operating license pursuant to Part 50 of;this chapter on or after
_(EFFECTIVE DATE OF THIS REGULATION).- However, if the construction permitzwas issued prior to [ EFFECTIVE DATE OF THIS REGULATION], the operating license applicant shall comply with the earthquake engineering critaria in Section VI of Appendix A to 10 CFR Part 100.
(
I.
- Introduction 56-l K
- 0
Each applicant for a construction permit, operating-license, design certification, or combined license is required by 550.34(a)(12),
550.34(b)(10), and General Design Criterion 2 of Appendix A to this Part to design nuclear power plant structures, systems, and components important to safety to withstand the effects of natural phenomena, such as earthquakes, without loss of capability to perform their safety functions.
Also, a condition of all operating licenses for nuclear power plants, as specified in 550.54(ee), is plant shutdown if the criteria in Paragraph IV(a)(3) of this appendix are exceeded.
These criteria implement General Design Criterion 2 insofar as it requires structures, systems, and components important to safety to withstand the effects of earthquakes.
II.
Scope The evaluations described in this appendix are within the scope of investigations permitted by 520.10(c)(1) of this chapter.
III.
Definitions As used in these criteria:
Combined license means a combined construction permit-and operating license with conditions for a nuclear power facility issued pursuant to Subpart C of Part 52 of this chapter.
Desion Certification means a Commission approval, issued pursuant to Subpart B of Part 52 of this chapter, of a standard design for a nuclear power 57
facility. A design so approved may be referred to as a " certified standard design."
The Ooeratino Basis Earthauake Ground Motion (OBE) is the vibratory ground motion for which those features of the nuclear power plant necessary for continued operation without undue risk to the health and safety of the public will remain functional. The Operating Basis Earthquake Ground Motion is only associated with plant shutdown and inspection unless specifically selected by the applicant as a design input.
A resoonse soectrum is a plot of the maximum responses.(acceleration, velocity, or displacement) of a family of idealized single-degree-of-freedom oscillators as a function of the natural frequencies of-the oscillators for a-given damping value.
The response spectrum is calculated for a specified~
vibratory motion input at the oscillators' supports.
The Safe Shutdown Earthauake Ground Motion (SSE) is the vibratory ground motion for which certain structures, systems, and components must be designed to remain functional.
The structures. systems. and comoonents reauired to withstand the effects of the Safe Snutdown Earthauake Ground Motion or surface deformation are those necessary to assure:
(1) The integrity of the reactor coolant-pressure boundary, (2) The capability to shut down the reactor and maintain it in a safe shutdown condition, or (3) The capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposures comparable to the guideline 58
exposures of $50.34(a)(1) of this chapter.
Surface deformation is distortion of soils or rocks at or-near the ground surface by the processes of folding, faulting ~, compression. or' extension as a result of varicus earth forces.
Tectonic surface deformation-is associated with earthquake processes.
IV. Application To Engineering Design The following are pursuant to the seismic and geologic design basis requirements of Paragraphs V(a) through (f) of Appendix-B to.Part 100 of this chapter:
(a) Vibratory Ground Motion.
(1) Safe Shutdown Earthquake Ground Motion. The Safe Shutdown Earthquake Ground Motion must be characterized by free-field-ground motion response spectra at-the free-ground surface or hypothetical rock outcrop, as appropriate.
In view of the limited data available on vibratory ground-motions of strong earthquakes, it usually'will-.be appropriate that the design response spectra be smoothed spectra developed' from an ensemble of response spectra related to the vibratory motions caused by more than one_ earthquake.
At. a minimum, the horizontal Safe Shutdown Earthquake Ground Motion at the -
foundation level' of the structures must be an appropriate response' spectrum with a peak ground. acceleration of at least 0.1g.
The nuclear power plant must be' designed so that, if the. Safe Shutdown Earthquake Ground Motion occurs, certain structures, systems, and components will remain functional.and within applicable stress and deformation limits. In addition to seismic loads, applicable concurrent normal operating,: functional, 59
and accident-induced loads must be taken into account in the design of these.
safety-related structures, systems, and components. The design of the nuclear power plant must also take into account the possible effects of the Safe-Shutdown-Earthquake Ground Motion on the facility foundations by ground-disruption, such as fissuring, lateral spreads, differential settlement,-
liquefaction, and landsliding, as required in Paragraph V(f) of~ Appendix B to Part 100 of this chapter.
The required safety functions of structures, systems, and components-must be assured during and after the vibratory ground motion associated with the Safe Shutdown Earthquake' Ground Motion through design, testing, or qualification methods.
The evaluation must take into account soil-structure interaction effects and the expected duration of vibratory motion. It is permissible to design for-strain limits in excess of yield strain in some of these safety-re1~ated-structures, systems, and components during the Safe Shutdown Earthquake Ground Motion and under the postulited concurrent loads, provided the necessary safety functions are maintained.
(2) Operating Basis Earthquake Ground Motion.
(1) The Operating Basis Earthquake Ground-Motion'must be characterized by response spectre.- The value of.the-Operating-Basis Earthquake Ground Motion must be set to one of the following choices:
(A) One-third or less of the Safe Shutdown Earthquake Ground Motion.
The requirements associated with this Operating Basis Earthquake. Ground MotionL in Paragraph (a)(2)(1)(B)(1) can be satisfied without the applicant performing:
explicit response:or design analyses, or (B) A value greater than one-third of the Safe Shutdown Earthquake
-Ground Motion. Analysis and design must be. performed to demonstrate that the-requirements associated with this Operating Basis: Earthquake Ground Motion in 60
Paragraph (a)(2)(1)(B)(1) are satisfied.
The design must take into account soil-structure interaction effer.ts and the expected duration of vibratory ground motion.
(1) When subjected to the effects of the Operating Biais Earthquake Ground Motion in combination with normal operating loads, all structures, systems, and components of the nuclear power plant necessary for continued operation without undue risk to the health and safety of the public must remain functional and within applicable stress and deformation limits.
(3) Required Plant Shutdren.'
If vibratory ground motion exceeding that of the Operating Basis E:-thquake Ground Motion or if significant plant damage occurs, the licensee must shut down the nuclear power plant.
Prior to resuming operations, the licensee must demonstrate to the Commission that no functional damage has occurred to those features necessary for continued operation without undue risk to the health and safety of the public.
(4) Required Seismic Instrumentation.
Suitable instrumentation must be provided so that the seismir. response of nuclear power plant features important to safety can be evaluated promptly after an earthquake.
(b) Surface Deformation.
The potential for surface deformation must be taken into account in the design of the nuclear power plant by providing reasonable assurance that in the event of deformation, certain structures, systems, and components will remain functional. In addition to surface deformation induced loads, the design of safety features must take into account seismic loads, including aftershocks, and applicable concurrent functional and accident-induced loads. The design provisions for surface deformation must be based on its postulated occurrence in any direction and Guidance is being developed in Draft Regulatory Guide DG-1017. " Pre-Earthquake Planning and ! mediate helear Power Plant operator Post-Earthquake Actions,"
61
1 azimuth and under any part of the nuclear power plant, unless evidence indicates this assumption is not appropriate, and must take into account the estimated rate at which the surface deformation may occur.
(c)
Seismically Induced Floods and Water Waves and Other Design conditions.
Seismically induced floods and water waves from either locally or distantly generated seismic activity and other design conditions determined pursuant to Paragraphs V(e) and (f) of Appendix B to Part 100 of this chapter must be taken into account in the design of the nuclear power plant so as to
.revent undue risk to the. health and safety of the public.
n PART 52 - EARLY SITE PERMITS; STANDARD DESIGN CERTIFICATIONS; AND COMBINED LICENSES FOR NUCLEAR POWER PLANTS 7.
The authority citation for Part 52 continues to read as follows:
AUTHORITY:
Secs. 103, 104, 161, 182, 183, 186, 189, 68 Stat. 936, 948, 953, 954, 955, 956, as amended, sec. 234, 83 Stat. 1244, as amended (42 U.S.C.
2133, 2201, 2232, 2233, 2236, 2239, 2282); secs. 201, 202, 206, 88 Stat. 1242, 1244, 1246, as amended (42 U.S.C. 5841, 5842, 5846).
8.
In 552.17, the introductory text of paragraph (a)(1) and paragraph (a)(1)(vi) are revised to read as follows:
552.17 Contents of applications.
(a)(1) The application must contain the information required by-50.33(a)-(d), the information required by 550.34(a)(12) and (b)(10), and, to l
the extent approval of emergency plans is sought under paragraph (b)(2)(ii) of 62
this section, the information required by 550.33(g) and (j), and 550.34(b)(6)(v).
The application must also contain a description and safety assessment of the site on which the facility is to be located, with appropriate attention to features affecting facility design.
The assessment must contain an analysis and evaluation of the major structures, systems, and components of the facility that bear significantly on the acceptability of the site under the radiological consequence evaluation factors identified in 550.34(a)(1) of this chapter.
Site characteristics must comply with Part 100 of this chapter.
In addition, the application should describe the following:
(vi) The seismic, meteorological, hydrologic, and geologic characteristics of the proposed site; 9.
In 10 CFR Part 52, Appendix Q, paragraph 8 is added to read as follows:
Appenoix Q to Part 52 - Pre-Application Early Review of the Site Suitability Issue.
8.
Notwithstanding paragraph 7, any application for renewal of an early site permit is subject to a full early site permit review.
PART 100 - REACTOR SITE CRITERIA 63
10.
The authority citation for Part 100 continues to read as foli i :
AUTHORITY:
Secs. 103, 104, 161, 182, 68 Stat. 936, 93'/,-948, 953, as amended (42 U.S.C. 2133, 2134, 2201, 2232); sec. 201, as amended, 202, 88 Stat. 1242, as amended, 1244 (42 U.S.C. 5841, 5842).
11.
The table of contents for Part 100 is revised to read as follows:
PART 100 - hiACTOR SITE CRITERIA Sec. 100.1 Purpose.
100.2 Scope.
100.3 Definitions.
100.4 Communications.
100.8 Information collection requirements: OMB approval.
Subpart A-Evaluation Factors for Stationary Power Reactor Site Applications Before (EFFECTIVE DATE OF THIS REGULATION) and for Test Reactors.
100.10 Factors to be considered when evaluating sites.
100.11 Determination of exclusion area, low population zone, and population center distance, t
i Evaluation Factors for Stationary Power Reactor Site Subpart B Applications on or After-(EFFECTIVE DATE OF THIS REGULATION).
64
4 100.20 Factors to be considered when evaluating sites.
100.21 Determination of exclusion area and population distribution.
100.22 Evaluation of potential man-related hazards.
APPENDIX A - Seismic and Geologic Siting Criteria for Nucle'ar Power Plants.
APPENDIX B - Criteria for the Seismic and Geologic Siting of Nuclear Power Plants on or After (EFFECTIVE DATE OF THIS REGULATION).
12.
Section 100.1 is revised to read as follows:
5100.1 Purpose.
(a) This part sets forth standards for evaluation of the suitability of proposed sites for stationary power and testing reactors subject to Part 50 or Part 52 of this chapter.
(b) This part identifies the factors considered by the Commission in the evaluation of reactor sites and the standards used in approving or disapproving proposed sites.
13.
Section 100.2 is revised to read as follows:
6100.2 Scope.
(a) This part applies to applications filed under Part 50 or Part 52 of this chapter for early site permit, construction permit, operating license, or combined license (construction permit and operating license) for power and tesfing reactors.
(b) The site criteria contained in this part apply primarily to reactors i
65 l
for which there is significant operating experience.
These site critsria can also be applied to other reactor types, such as for reactors that are novel in design and unproven as prototypes or pilot plants.
For plants without significant operating experience, it is expected that these basic criterio will be applied in a manner that takes into account the lack of' experience.
In the application of these criteria which are deliberately flexible, the safeguards provided, either site isolation or engineered features, should reflect the lack of certainty that only experience can provide.
14.
Section 100.3 is revised to read as follows:
)
!i100.3 Definitions.
As used in this part:
Exclusion area means that area surrounding the reactor, in which the reactor licensee has the authority to determine all activities including exclusion or removal of personnel and property from the area. This area may be traversed by a highway, railroad, or waterway, provided these are not so close to the facility as to interfere wit.1 normal operations of the facility and prnvided appropriate and effective arrangements are made to control traffic on the h'ghway, railroad, or waterway, in case of emergency, to protect the public health and safety.
Residence within the exclusion area shall normally be prohibited.
In any event, residents shall be subject to ready removal in case of necessity. Activities unrelated to operation of the reactor may be permitted in an exclusion area under appropriate limitations, provided that no significant hazards to the public health and safety will result.
Low occulation zone means the area immediately surrounding the exclusion i
area which contains residents, the total ntmber and density of which are such 66
that there is a reasonable probability that appropriate protective measures could be taken in their 'ehalf in the event of a serious accident. These guides do not specify a permissible population density or total population within this zone because the situation may vary from case to case. Whether a specific nur.ber of people can, for example, be evacuated from a specific area, o'r instructed to take shelter, on a timely basis will depend on many factors such as location, number and size of highways, scope and extent of advance planning, and actual distribution of residents within the area.
Pooulation center distance means the distanca from the reactor to the nearest boundary of a densely populated center containing more than about 25,000 residents.
Pqw.gr reactor means a nuclear reactor of a type described in il50.21(b) or 50.22 of this chapter designed to produce electrical or heat energy.
Testina reac1qr means a testina facility as defined in $50.2 of this chapter.
15.
Section 100.4 is added to read as follows:
$100.4 Comunications.
Except where otherwise specified in this part, all correspondence, reports, applications, and other written comunications submitted pursuant to 10 CFR 100 should be addressed to the U.S. Nuclear Regulatory _Comission, ATTN: Document Control Desk, Washington, DC 20555, and copies sent to the appropriate Regional Office and Resident Inspector. Comunications and reports may be delivered in person at the Comission's offices at 2120 L Street, NW., Washington DC, or at 11555 Rockville Pike, Rockville, Maryland.
16.
Section 100.8 is revised to read as follows:
67 l
$100.6 Information collection requirements: OMB approval.
(a) The Nuclear Regulatory Commission has submitted the information collection requirements contained in this part to the Office of Management and Budget '"tiB) for approval as required by the Paperwork Reduc' tion Act of 1980(44 U.S.C. 3501 et seq.). OMB has approved the information collection requirements contained in this part under control number 3150-0093.
(b) The appen ed information collection requirements contained in this part appear in Appendix A and Appendix B.
17.
A heading for Subpart A is added directly before $100.10 to read as follows:
Evaluation rectors for Stationary Power Reactor Site Subpart A Applications Before (EFFECTIVE DATE OF THIS REGULATION) and for Test Reactors.
18.
Section 100.10 is added to read as follows:
$100.10 factors to be considered when evaluating sites.
Factors considered in the evaluation of sites include those relating both to the proposed reactor design and the characteristics peculiar to the site. It l
is expected that reactors will reficct through their design, construction and operation an extremely low probability for accidents that could result in release of signifit. ant quantities of radioactive fission products. In addition, the site 1ccation and the engineered features included as safeguards against the hazardous 68 L
1 consequences of an accident, should one occur, should insure a low risk of public exposure.
In particular, the Commission will take the following factors into consideration in determining the acceptability of a site for a power or testing reactor:
(a)
Characteristics of reactor design and proposed operation including--
(1) Intended use of the reactor including the proposed maximum power level and the nature and inventory of contained radioactive materials; (2) The extent to which generally accepted engineering standards are applied to the design of the reactor; (3) The extent to which the reactor incorporates unique or unusual features having a significant bearing on the probability or consequences of accidental release of radioactive materials; (4) The safety features that are to be engineered into the facility and those barriers that must be breached as a result of an accident before a
- elease of radioactive material to the environment can occur.
(b) Population density and use characteristics of the site environs, including the exclusion area, low population zone, and the populatica center distance.
(c)
Physical characteristics of the
- site, including seismology, meteorology, geology, cnd hydrology.
(1) Appendix A to Part 100, ' Seismic and Geologic Siting Criteria for Nuclear Power Plants,' describes the nature of investigations required to obtain the geologic and seismic data necessary to determine site. suitability and to provide reasonable assurance that a nuclear power plant can be constructed and operated at a proposed site without undue risk to the health and safety of the
~
public.
It describes procedures for determining the quantitative vibratory ground motion design basis at a site due to earthquakes and describes information needed to determine whether and to what extent a nuclear power plant need be 69
designed to withstand the effects of surface faulting.
(2) Heteorological conditions at the site and in the surrounding area should be considered.
(3) Geological and hydrological characteristics of the proposed site may have a bearing on the consequences of an escape of radioactive material from the facility.
Special precautions should be planned if a reactor is to be located at a site where a significant quantity of radioactive effluent might accidentally flow into nearby streams or rivers or might find ready access to underground water tables.
(d) Where unfavorable physical characteristics of the site exist, the proposed site may nevertheless be found to be acceptable if the design of the facility includes appropriate and adequate compensating engineering safeguards.
19.
Section 100,11 is revised to read as follows-5100.11 Determination of exclusion area, low population zone, and population center distance.
(a) As an aid in evaluating a proposed site, an applicant should assume a fistion product release' from the core, the expected demonstrable leak rate from the containment and the meteorological conditions pertinent to his site to derive an exclusion area, a low population zone and population center distance. For the purpose of this analysis, which shall set forth the basis for the numerical values used, the applicant should determine the following:
(1) An exclusion area of such size that an individual located at any
'The fission product release assmed for these calculations should be based upon a snajor arcident, hypothestled for purposes of site entlysis or postulated fran considerettons of possible accioental events, that would result in potent 141 hazards not exceedeJ by those from any accident considered credible. $uch accider,ts have generally been assmed to result in substantial neltdown of the core with subsequent release of apprectable quantitles of fission products.
70
1 4
point on its boundary for two hours immediately following onset of the postulated fission product release would not receive a total radiation dose to the whole body in excess of 25 rem
(2) A low population zone of such size that an iridividual located at any point on its outer boundary who is exposed to the radioactive cloud resulting from the postulated fission product release (during the entire period of its pas: age) would not receive a total radiation dose to the whole body in excess of 25 rem or a total radiation dose in excess of 300 rem to the thyroid from iodine exposure.
(3) A population center distance of at least one and one-third times the distance from the reactor to the outer boundary of the low population zone.
In applying this guide, the boundary of the population center shall be determined upon consideration of population distribution.
Political boundaries are not controlling in the application of this guide.
Where ver/ large cities are involved, a greater distance may be necessary because of total integrated population dose consideration.
(b) For sites for multiple reactor facilities consideration should be given to the following:
(1) If the reactors are independent to the extent that an accident in one reactor would not initiate an accident in another, the size of the
' The whole body dose of 25 rem referred to above corresponds numerically to the once in a lifetime accidental or emergency dose for radiation workers which, according to NCRP recommendations may be disregarded in the deterraination of their radiation exposure status (see NBS Handbook 69 dated June.5, 1959).
However, neither its use nor that of the 300 rem value for thyrcid exposure as set forth in these site criteria guides are intended to imply that these numbers constitute acceptable limits for emergency doses to the public under accident-conditions. Rather, this 25 rem whole body value and the 300 rem thyroid value have been set forth in these guides as reference values, which can be used in the evaluation of reactor sitos with respect to potential reactor accidents of exceedingly low probability of occurrence, and low risk of public exposure to radiation.
71
exclusion area, low population zone ud population center distance shall be fulfilled with respect to each reactor individually. The envelopes of the plan overlay of the areas so calculated shall then be taken as their respective boundaries.
(2) If the reactors are interconnected to the extent that an accident in one reactor could affect the safety of operation of any other, the size of the exclusion area, low population zone and population center distance shall be based upon the assumption that all interconnected reactors emit their postulated fission product releases simultaneously.
This requirement may be reduced in relation to the degree of coupling between reactors, the probability of concomitant accidents and the probability that an individual would not be exposed to the radiation effects from simultansous releases.
The applicant would be expected to justify to the satisfaction of the Commission the basis for such a reduction in the source term.
(3) The applicant is expected to show that the simultaneous operation of multiple reactors at a site will not result in total radioactive effluent releases beyond tne allowable limits of applicable regulations.
NOTE:
For further guidance in developing the exclusion area,.the low population zone, and the population center distance, reference is made to Technical Information Document 14844, dated March 23,1962, which contains a procedural method and a sample calculation that result in distances roughly reflecting current siting practices of the Commission., The calculations-described in Technical Information. Document 14844 may be used as a point of
' departure for consideration of particular site requirements which may result from evaluation of the characteristics of a particular reactor, its purpose and method I
of operation.
Copies of Technical Information Document-14844 may be obtained l
from the Commission's Public Document Room, 2120 L Street, NW. (Lower Level),
i 72 l
l
...... _ -.... ~ _ -
Washington, DC, or by writing the Director of Nuclear Reactor Regulation, U.S.
Nuclear Regulatory Comission, Washington, DC. 20555.
i 20.
Subpart B (55100.20 - 100.22) is added to read as follows:
Subpart B-Evaluation Factors for Stationary Power Reactor Site Applicationi on or Af ter [ EFFECTIVE DATE OF THIS REGULATION).
$100.20 Factors to be considered when evaluating sites.
The Comission will take the following factors into consideration in determining the acceptability of a site for a stationary power reactor:
(a) Population density and use characteristics of tht. site environs, including the exclusion area, the population distribution, and site-related characteristics must be evaluated to determine whether individual as well as societal risk of potential plant accidents is low, and that site-related characteristics would not prevent the development of a plan to carry out suitable protective actions for members of the public in the event of emergency.
(b) The nature and proximity of man-related hazards (e.g., airports, dams, transportation routes, military and chemical facilities) must be evaluated to determine whether the plant design can accomodate.comonly occurring hazards, and whether the risk of other hazards is very low.
(c) Physical characteristics of the site, including seismology, meteorology, geology, and hydrology.
(1) Appendix D,
- Criteria for the Seismic and Geologic Siting of Nuclear Power Plants on or After [ EFFECTIVE DATE OF THIS REGULATION),' describes the criteria and nature of. investigations required to obtain the geologic and seismic data necessary to determine site suitability.
73
-l (2) Meteorological characteristics of the site that are necessary for safety analysis or that may have an impact upon plant design (such as maximum probable wind speed and precipitation) must be identified and characterized.
(3) Factors important to hydrological radionuclide transport (such as
- soil, sediment, and rock characteristics, adsorpt' ion and retention coefficients, ground water velocity, and distances to the nearest surface body of water) must be obtained from on-site measurements. The maximum probable flood along with the potential for seismic induced floods discussed in Appendix is must be estimated using historical data.
5100.21 Determination of exclusion area and population distribution.
(a) Each reactor facility must have an exclusion area, as defined in 5100.3(a) of this part.
(1) For sites with a single reactor facility, the distance to the exclusion area boundary at any point (as measured from the reactor center point) shall be at least 0.4 miles (640 meters).
l (2) For sites with multiple reactor facilities, consideration mest be given to the following:
If the reactors are independent to the extent that an accident in one reactor would not initiate an accident in another, the size of l
each exclusion area must be determined with respect to each reactor individually.
The exclusion area for the site must then be taken as the plan overlay of the sum of the exclusion areas for each reactor.
If the reactors are interconnected to the extent that an accident in one reactor would initiate an accident in another, the size of the exclusion-area for'each reactor must be determined on a csse by case basis.
(b)(1) If the offsite population density at the proposed site exceeds the values given in paragraph (b)(2) of this section, the site will not be approved 74
by the Commission unless the applicant demonstrates either:
(i)
That there are no reasonably available alternative sites with significantly lower population densities, or (ii) That the proposed site is preferred over an alternative site with significantly lower population density on the basis of other considerations.
(2) The population density, including weighted transient population, projected at the time of initial site approval or early site permit renewal should not exceed 500 people per square mile averaged over any radial distance out to 30 miles (cumulative population at a distance divided by the total-circular area at that distance).
The projected population density, including
' weighted tr:nstent population, 40 years after the time of initial site approval or early site permit renewal should not exceed 1000 people per square mile averaged over any radial distance out to 30 miles.
(3) Transient population must be included for those sites where a significant nwaber of peopic (other than those just pusing through the area) work, reside part-time, or engage in recreation 1 activities and are not' permanent residents of the area. The transient population should be considered for siting purposes by weighting the transient popuidion according to the fraction of the time the transients are in the area.
(c) Physical characteristics of the proposed site, such as egress limitations from the area surrounding the site, that could pose a significant impediment to the development of emergency plans, must be identified.
$100.22 Evaluation of Man-related Hazards.
(a) Potential hazards to the plant from man-related activities 75 j
4 associated with nearby transportation routes, military, and industrial facilities must be identified and their potential effects evaluated. Potential hazards to the plant include such effects as explosions, fires, toxic and/or flamable chemical releases, dams (both upstream and downstream), pipeline accidents, and aircraft crashes and impacts.
(b) The effects of offsite hazards must have a very low probability of affecting the safety of the plant.
The likelihood and consequences of offsite hazards must be estimated using data and assumptions that are as realistic and representative of the site as is practical. The design bases for which the plant is designed must be specified.
21, Appendix B to Part 100 is added to read as follows:
APPFNDIX B TO PART 100 -- CRITERIA FOR THE SEISHIC AND GEOLOGIC SITING OF NUCLEAR POWER PLANTS ON OR AFTER [ EFFECTIVE DATE OF THIS REGULATION)
General Information This appendix epplies to applicants who apply for an early site permit or combined license pursuant to Part 52 of this chapter, or a construction permit or operating license pursuant to Part 50 of this chapter on or after (EFFECTIVE DATEOFTHISREGULATION). However, if the construction permit was issued prior to (EFFECTIVE DATE OF THIS REGULATION), the operating license applicant shall comply with the seismic and geologic siting criteria in Appendix A to Part 100 of this chapter.
I.
Purpose 76
. _. ~. _ _. _. _ _. _. _ _
General Design Criterion 2 of Appendix A to Part 50 of this chapter requires that nuclear power plant structures, systems, and components important to safety be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without loss of capability to perform their safety functions. It is the purpose of these criteria l
to set forth the principal seismic and geologic considerations that guide the Commission in its evaluation of the suitability of proposed sites for nuclear power plants and the suitability of the plant design bases established in consideration of the seismic and geologic characteristics of the proposed sites.'
These criteria are based on the current geophysical, geological, and seismological information concerning faults and earthquake occurrences and effects.
They will be revised as necessary when more complete information becomes available.
- 11. Scope These criteria, which apply to nuclear power plants, describe the nature of the investigations required to obtain the geologic and seismic data necessary to determine site suitability and provide reasonable assurance that a nuclear power plant can be constructed and operated at a proposed site without undue risk to the health and safety of the public. Geologic and seismic factors required to B
be taken into account in the siting and design of' nuclear power plants are identified.
The investigations described in this appendix -are within the scope of Considerations presented in this regulation are general. Acceptable nthods and additional discussion are provtced in regulatory guides and standard review plan sections.
77
1 4
investigations permitted by 6 50.10(c)(1) of this chapter.
Each applicant for a construction permit, operating license, early site permit, or combined license shall investigate all seismic and geologic factors that may affect the design and operation of the proposed nuclear power plant irrespective of whether such factors are explicitly included in these criteria.
Both deterministic and probabilistic evaluations must be conducted to determine site suitability and seismic desig.. requirements for the site.
Additional investigations or more conservative determinations than those included in these criteria may be required for sites located in areas with complex geology, recent tectonic deformation, or in areas of high seismicity. If an applicant believes that the particular seismic and geologic characteristics of a site indicate that some of these criteria, or portions thereof, need not be satisfied, the applicant shall identify the specific sections of these criteria in the license application and present supporting data to clearly justify such departures.
The Director, Office of Nuclear Reactor Regulation approves any deviations.
!!! Definitions As used in these criteria:
A caoable tectonic source is a tectonic structure that can generate botn earthquakes and tectonic surface deformation such as faulting or folding at or near the surface in the present seismotectonic regime.
It is characterized by at least one of the following characteristics:
(1) The presence of surface or near-surf ace deformation of landforms or geologic deposits of recurring nature within the last approximately 500,000 years or at least once in the last approximately 50,000 years.
(2)
A reasonable association with one or more large earthquakes or sustained earthquake activity that is usually accompanied by significant surface 78
1 deformation.
(3)
A structural association with a capable tectonic source having characteristics in paragraph (iii) (1) of this definition so that movement on one could be reasonably expected to be accompanied by movement on the other.
In some cases, the geologic evidence of past activity at or near the ground surface along a particular capable temnic source may be obscured at a particular site. This might occur, for example, at a site having a deep overburden. For these cases, evidence may exist elsewhere along the structure from which an evaluation of its characteristics in the vicinity of the site can be reasonably based.
This evidence must be used in determining whether the,
structure is a capable tectonic source within this definition.
Notwithstanding the foregoing paragraphs in (1), (2) and (3), of this definition, structural association of a structure with geologic structural features that are geologically old (at least pre-Quaternary) such as many of those found in the Eastern region of the United States must, in the absence of conflicting evidence, demonstrate that the structure is not a capable tectonic source within this definition.
Combined license means a combined construction permit and operating license with conditions for a nuclear power facility issued pursuant to Subpart C of Part 52 of this chapter.
A deterministic source earthouake (DSQ is the largest earthquake that can reasonably be expected to occur in a given seismic source in the current tectonic regime, and is to be used in a deterministic analysis, it is generally based on the maximum historical earthquake associated with that seismic source, unless recent geological evidence warrants a larger earthquake, or where the rate of occurrence of earthquakes indicates the itkelihood of larger than the largest 79
historical event.
Early Site Permit means a Commission approval, issued pursuant to subpart A of Part 52 of this chapter, for a site or sites for one or more nuclear power facilities.
A fault it a tectonic structure along which differential slippage of the adjacent earth materials has occurred parallel to the fracture plane. A fault may have gouge or breccia between its two walls and includes any associated monoclinal flexure or other similar geologic structural feature.
The maanitude of an earthquake is a measure of the size of an earthquake and is related to the energy released in the form of seismic waves. Magnitude means the numerical value on a standardized scale such as, but not limited to, Homent Magnitude, Surface Wave Magnitude, Body Wave Magnitude, or Richter Magnitude scales.
A rfJioonse soectrum is a plot of the maximum responses (acceleration, velocity, or displacement) of a family of idealized single-degree-of-freedom oscillators as a function of the natural frequencies of the oscillators for a given damping value.
The response spectrum is calculated. for a specified vibratory motion input at the oscillators' supports.
The Safe Shutdown Earthauake Ground Motion (SSE) is the vibratory ground l
motion for which certain structures, systems, and components must be designed to remain functional.
A seismic source is a general term referring to both seismogenic sources 80
and capable tectonic sources.
I A leismoaenic source is a portion of the earth that has uniform earthquake j
potential (same deterministic source earthquake and frequency of recurrence) distinct from the surrounding area. A seismogenic cource wiil not cause surface displacements. Seismogenic sources cover a wide range of possibilities from a well-defined tectonic structure to simply a large region of diffuse seismicity (seismotectonic province) thought to be characterized by the same earthquake recurrence model. A seismogenic source is also characterized by its involvement in the current tectonic regime as reflected in the Quaternary (approximately the last 2 million years) geologic history.
Surface deformation is distortion of soils or rocks at or near the ground surface by the processes of folding, faulting, compression, or extension ~as a result of various earth forces. Tectonic surface deformation is associated with earthquake processes.
Surface faultina is differential ground displacement at or near the surface caused directly by fault movement and is distinct from nontectonic types of ground disruptions, such as landslides, fissures, and craters.
IV. Required Investigations The geological, seismological, and engineering characteristics of a site and its environs must be investigated in sufficient scope and detail to permit an adequate evaluation of the proposed site, to provide sufficient information 81 l
7 to support both probabilistic and deterministic evaluations required by these criteria, and to permit adequate engineering solutions to actual or potential geologic and seismic effects at the proposed site. The size of the region to be investigated and the type of data pertinent to the investigations must be determined by the nature of the region surrounding the ' proposed site. The investigations must be carried out by a review of the pertinent literature and field investigations as identified in paragraphs (a) through (e) of this section.
(a) Vibratory Ground Motion.
The purpose of these investigations is to obtain information needed to assess the Safe Shutdown Earthquake ground motion. The seismic sources (capable tectonic sources and seismogenic sources) in the site region must be identified and evaluated. The deterministic source earthquakes must be evaluated for each seismic source.
(b)
Tectonic Surface Deformation.
The purpose of these investigations is to assess the potential for tectonic surface deformation near the site and, if any, to what extent the nuclear power plant needs to be designed for these occurrences.
(c) Nontectonic Deformation.
The purpose of those investigations is to assess the potential for surface deformations not directly attributable to tectonics, such as those associated-with subsidence or collapse as in karst terrain, glacially induced offsets, and growth faulting. FaragraphIV(b)lconcernsinvestigationsrequiredfortectonic-surface deformation that can occur coseismicalin Nontectonic phenomena can-represent significant surface displacement hazards to a site, but can in many cases be monitored, controlled, or mitigated by engineering, or it can be demonstrated that conditions that were the cause of the displacements no longer exist. Geological and geophysical investigations must be carried out-to identify 82 e
and define nontectonic deformation features and, where possible, distinguish them from tectonic surface displacements. If such distinction is not possible, the questionable features must be treated as tectonic deformation.
(d)
Seismically Induced Floods and Water Waves.
The purpose of these investigations is to assess the potential for nearby and distant tsunamis and other waves that could affect coastal sites.
Included in this assessment is the determination of the potential for slides of earth material that could generate waves.
Information regarding distant and locally generated waves or tsunamis that have affe:ted the site, and available evidence of runup and drawdown associated with these events, shall be analyzed.
Local features of coastal or undr sea. topography which could modify wave runup or drawdown must be considered. Fo sites located near lakes or rivers, analyses must include the potential for seismically induced floods or water waves, as, for example, from the failure during an earthquake of a dam upstream or from s!! des of earth or debris into a nearby lake.
(e) Volcanic Activity.
The purpose of these investigations is to assess the potential volcanic hazards that would adversely affect the site.
V. Seismic and Geologic Design Bases (a) Determination of Deterministic Source Earthquakes.
For each seismogenic and capable tectonic source identified in Paragraph IV(a), the deterministic source earthquake must be evaluated. At a minimum, the deterministic source earthquake must be the largest historical earthquake in each
=
source. The uncertainty in determining the deterministic source earthquakes must I
be accounted for in the probabilistic analysis.
4 (b) Determination of the Ground Motion at the Site.
83
I 7
4 The ground motion at the site must be estimated from all earthquakes, including the deterministic source earthquake associated with each source, which could potentially affect the site using both probabilistic and deterministic approaches. In the deterministic approach, the deterministic source earthquake associated with each source must be assumed to occur at the'part of the source which is closest to the site.
Appropriate models, including local site conditions, must be used to account for uncertainty in estimating the ground motion for the site.
The ground motion is defined by both horizontal and vertical free-field ground motion response spectra at the free ground surface or hypothetical rock outcrop, as appropriate.
(c) Determination of Safe Shutdown Earthquake Ground Motion.
The Safe Shutdown Earthquake Ground Motion is characterized by free-field ground motion response spectra at the free ground surface or hypothetical rock outcrop, as appropriate.
These spectra are developed from or compared to the ground motions determined in Paragraph V(b).
Deterministic and probabilistic seismic hazard evaluations must be used to assess the adequacy of the Safe Shutdown Earthquake Ground Motion. The annual probability of exceeding the Safe Shutdown Earthquake Ground Motion is considered acceptably low if it is less than the median annual probability computed from the current (EFFECTIVE DATE OF THIS REGULATION) population of nuclear power plar,ts.
' At a minimum, the horizontal Safe Shutdown Earthquake Ground Motion at the foundation level of the structures must be an appropriate response spectrum with a peak ground acceleration of at least 0.1g.
(d) Determination of Need To Design for Surface Tectonic and Nontectonic Deformations.
Sufficient geological, seismological, and geophysical data must be provided to clearly establish that surface deformation need not be taken into account in the design of a nuclear power plant.
When surface deformation is likely, an 84
assessment of the extent and nature of surface deformations must be characterized.
(e) Determination of Design Bases for Seismically Induced Floods and Water Waves.
The size of seismically induced floods and water waves that could affect a site from either locally or distantly generated seismic activity must be determined, taking into consideration the results of the investigation required by paragraph (d) of section IV in this Appendix.
(f) Determination of Other Design Conditions.
(1) Soil Stability. Vibratory ground motions determined in Paragraph V(b) can cause soil instability from ground disruption such as fissuring,-lateral spreads, differential settlement, and liquefaction, which is not directly related to surface faulting. Geological features that could affect the foundations of the proposed nuclear power plant structures must be evaluated, taking into account the information concerning the physical properties of materials underlying the site and the effects of the vibratory ground motion determined in Paragraph V(b).
(2) Slope stability. Stability of all slopes, both natural and artificial, must be considered, the failure of which could adversely affect the nuclear power.
pl ant.
An assessment must be made of the potential effects of erosion or deposition and of combinations of erosion or deposition with seismic activity, taking into account information concerning the physical properties of the materials underlying the site and the effects of the vibratory ground motion determined in Paragraph V(b).
(3) Cooling water supply. Assurance of an adequate cooling water supply for emergency and long-term shutdown decay heat removal shall be considered in-the design of the nuclear power plant, taking into account information concerning-the physical properties of the materials underlying the site, the effects'of the Safe Shutdown Earthquake Ground Motion, and the design basis.for tectonic'and 85 i
=
l nontectonic surface deformation. Consideration of river blockage or diversion or other f ailures that may block the flow of cooling water, coastal uplift or subsidence, tsunami runup and drawdown, and the failure of dams and intake structures must be included in the evaluation where appropriate.
(4)
Distant structures. Those structures that are not located in the imediate vicinity of the site but are safety-related must be designed to withstand the effect of the Safe Shutdown Earthquake Ground liotion. The design basis for surface f aulting must be determined on a basis comparable to that of the nuclear power plant, taking into account the material underlying the structures and the different location with respect to that of the site.
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VI. Application To Engineering Design Pursuant to the seismic and geologic design basis requirements of paragraphs V(a) through (f), applications to engineering design are contained in Appendix 5 to Part 50 of this chapter for the following areas:
(a)
Vibratory ground motion.
(1)
Safe Shutdown Earthquake Ground Motion (SSE).
(2)
Operating Basis Earthquake Ground Motion (OBE).
(3)
Required Plant Shutdown.
(4)
Required Seismic Instrumentation.
(b)
Surface Deformation.
(c)
Seismically Induced floods and Water Waves and Other Design Conditions.
f n
Dated at Rockville, Maryland, this b day of 1 # e X/1992.
Fo 'the Nuc1 r Regulatory Comission.
amuelJ. Chi (1 L'
Secretary of t ie Comission.
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