ML20140F575
| ML20140F575 | |
| Person / Time | |
|---|---|
| Issue date: | 11/06/1992 |
| From: | Shao L NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | NRC |
| Shared Package | |
| ML20007G200 | List: |
| References | |
| FRN-57FR47802, RULE-PR-100, RULE-PR-50, RULE-PR-52, TASK-DG-1015, TASK-RE AD93-1-038, AD93-1-38, NUDOCS 9705050069 | |
| Download: ML20140F575 (23) | |
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November 6,1992 T0: REGULATORY GUIDE DISTRIBUTION LIST FOR DIVISION 1
SUBJECT:
SPECIFIC ISSUES FOR COMMENT This proposed Draft Regulatory Guide DG-1015, " Identification and Characterization of Seismic Sources, Deterministic Source Earthquakes, and Ground Motion," outlines concepts and procedures to be used in conjunction with the probabilistic/ deterministic seismic hazard evaluations. The ration-ale for the approach is discussed in Section V.B(3) of the Federal Reaister notice that presents the revision of Appendix A to Part 100 for public com-ment. The specific questions stated below are contained in Section XI.B of the same Federal Reaister notice. The staff is currently performing confirmatory studies to evaluate and refine these proposed procedures. A limited study has been completed demon-strating the feasibility of procedures and the validity of the concepts. However, the NRC staff would like to solicit comments on the concepts outlined in the proposed guide. Results of the application of the proposed procedure to four test sites are in a letter report from D. Bernreuter of LLNL to A 24, 1992, which is available in the NRC D co. Murphy of NRC, datedNW, Public Document pying for a fee. Room at 2120 L Street Washington, DC, for inspection or September , There are divergent views on the role probabilistic seismic hazard ! analysis should play in the licensing arena. There is a general consensus ' among the NRC staff that the revised seismic and geological siting criteria l 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 cur-rent generation of nuclear power plants. There is a general consensus that l ground motions should be calculated using deterministic methods once the con- l trolling earthquakes are determined. With regard to the role of the probabi- l listic analysis, views range from an advocacy of a predominantly probabilistic analysis to the probabilistic/ deterministic evaluation proposed here to a pre-dominantly deterministic approach as used ' currently. Given these divergent l views, the NRC staff invites comments regarding the use of probabilistic seis- ! mic hazard analysis and the balance between the deterministic and probabilis-tic evaluations. This and other associated issues are itemized below. As the I detailed technical studies are completed some of the staff positions may be l confirmed, but specific comments would be helpful at this time. I
- 1. In making use of both deterministic and probabilistic evaluations, how should they be combined or weighted, that is, should one domi-nate the other? (The NRC staff feels strongly that deterministic investigations and their use in the development and evaluation of the Safe Shutdown Earthquake Ground Motion should remain an impor-tant aspect of the siting regulations for nuclear power plants for I 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.)
9705050069 970422 PDR PR 50 57FR47802 PDR,
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- 2. In making use of the probabilistic and deterministic evaluations as proposed in Draft Regulatory Guide DG-1015, is the proposed proce-4 dure 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 statis-tical measures, such as mean or 85th percentile? (The NRC staff has 1 selected probability of exceedance levels associated with the median i hazard analysis estimates as they provide more stable estimates of ,
controlling earthquakes.) I 1 , 4. The proposed Appendix B to 10 CFR Part 100 states: "The annual probability of exceeding the Safe Shutdown Earthquake Ground Motion l i is considered acceptably low if it is less than the median annual I probability computed from the current [ EFFECTIVE DATE OF THE REGU-LATION] population of nuclear power plants." This is a relative criterion without any specific numerical value of the annual pro-bability of exceedance because of the current status of the pro- ) babilistic seismic hazard analysis. However, this requirement 1 ensures that the design levels at new sites will be comparable to I those at many existing sites, particularly more recently licensed sites. Method-dependent annual probabilities or target levels (e.g., IE-4 for Lawrence Livermore National Laboratory or 3E-5 for the Electric Power Research Institute) are identified in the pro-posed 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 differ-ent 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 i the criteria presented in Draft Regulatory Guide DG-1015, the !
average of results for the 5 Hz and 10 Hz spectral velocities was I used to establish the probability of exceedance level. Controlling l earthquakes were evaluated for this frequency band, for the average of 1 and 2.5 Hz spectral responses, and for peak ground I acceleration.) , 1 Comments on the above issues should be accompanied by appropriate ; supporting data. Written comments should be sent to the Regulatory Publications Branch, DFIPS, Office of Administration, U.S. Nuclear Regulatory ) Commission, Washington, DC 20555. D l Lawrence C. Shao, Director l Division of Engineering Office of Nuclear Regulatory Research
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/ h U.S. NUCLEAR REGULATORY COMMISSION November 1992 Division 1 0 'A 0FFICE OF NUCLEAR REGULATORY RESEARCH y ,g Task DG-1015 DRAFT REGULATORY GUIDE D \*****/
Contact:
A. J. Murphy (301)492-3860 DRAFT REGULATORY GUIDE DG-1015 IDENTIFICATION AND CHARACTERIZATION OF SEISMIC SOURCES, DETERMINISTIC SOURCE EARTHQUAKES, AND GROUND MOTION
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A. INTRODUCTION dY 1 ,
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3 Paragraph IV, " Required Investigations," of proposed <Appen% B, 4 " Criteria for the Seismic and Geologic Siting of NucleIrm,pow $) Plants on or 5 After [ Effective Date of this Regulation]," to 10 CFR Parts 100, " Reactor Site yw v 6 Criteria," requires investigations to assess the,p osed < site for (a) vibra-7 tory ground motion, (b) tectonic surface defor mati % 'o and (c) nontectonic s 8 deformation. ParagraphV(inathroughd)pGroposedAppendixBto10CFR 4cf 9 Part 100 requires the determination of(fi)htdininistic source earthquakes,
) 10 (b)groundmotionsatthesite,(c)isafeShuYdownearthquakegroundmotior.: / p u v 11 and (d) the need to design for supfacelectonic and nontectonic deforme .:ns.
12 The purpose of this guidAs tDpNvide general guidance on acceptable o a 13 procedures to (1) identify and chiracterize seismic sources, (2) determine 14 deterministicsourceearthquaN('DSEs)andcontrollingearthquakes(CEs),and 15 (3) compare the seismic ny m hazard level to that at operating plants. These 16 procedures are requiredxby Appendix B to 10 CFR Part 100. eg y 17 This guide;contal Appendix A contains a list of 18 definitions (of peOin$ns nt terms. Appendix several appendices. B describes the acceptance criteria 19 for theinnudllprdbability of exceedence level for safe shutdown earthquake 20 groundmotjons. Appendix C discusses the determination of controlling This regulatory guide is being issued in draft form to involve the public 15 the early stages of the develop-ment of a regulatory position in this arva. It has not received complete staff review and does not repnsent an of ficial NRC staff position. Public comments are being solicited on the draft guide (including any implementation schedule) and its assoc 1-ated regulatory analysis or value/ impact statement. Comments should be accompanied by appropriate supporting Jata. Written comments may be submitted to the Regulatory Publications Branch, DFIpt nffice of Administra- l tion U.S. Nuclear Regulatory Comission, Washington, DC 20555 Copies of cos ,nts received n.4
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at the NRC Public Document Room 2120 L Street NW., Washington, DC. Comments will be most helpful if receiveo O I by March 24,1993. l Requests for single copies of draft guides (which may be reproduced) or for placement on an automatic distri- l bution list for single copies of future draft guides in specific divisions should be made in writing to the U.S. Nuclear Regulatory Commission, Washington, DC 20555, Attention: Office of Administration, Distribution and Mail Services Section.
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I earthquakes from the probabilistic analysis, and Appendix D discusses the 2 investigations to characterize seismic sources. 3 Any information collection activities mentioned in this regulatory guide 1 4 are contained as requirements in the proposed amendments to 10 CFR Part 50 5 that would provide the regulatory basis for this guide. The proposed amend- i 6 ments have been submitted to the Office of Management and Budget for clearance 7 that may be appropriate under the Paperwork Reduction Act. Such clearance, if j 8 obtained, would also apply to any information collection activities mentioned ! 1 in this guide. i N 11 P. DISCUSSION 12 13 ao pendix B requires consideration of both probabilistic and deterministic ! 14 approaches to obtain site geologic and seismologic characteristics. The ! 15 approach required by Appendix A to 10 CFR Part 100 for determining the safe l 16 shttdown earthquake ground motion (SSE) is deterministic, and thus does not I 17 cxplicitly incorporate uncertainties about the seismic hazard into the ground 18 motion determination. Current probabilistic seismic hazard analyses rely 19 heavily on expert opinion, and since their results are driven by the tails of 20 the probability distributions, they need to be benchmarked by simpler deter-21 ministic analysis. Therefore, the role of the probabilistic analysis is to 22 ensuie that the uncertainties have been included in the assessment of the 23 seismic hazard, and the role of the deterministic analysis is to ensure that 24 the resultant design provides protection against a scenario based on 25 historical .eismicity and recent geological history. 26 Before providing specific guidance, the following synopsis of the 27 development of the SSE is presented. The development of the SSE follows two 28 required, parallel paths. One path is referred to in Figure 1 as Determinis-29 tic Analysis (DA) and one path as Probabilistic Analysis (PA). The initial 30 s',ep in the process is to obtain the site- and region-specific geological, 31 seismological, and geophysical data. Branching from the first step to DA, the 32 seismic sources around the site are identified and the deterministic source 33 earthquake (DSE) for each source is determined. Ground motion is calculated 34 using DSEs and the methods acceptable to the NRC staff Aescribed in Standard 35 Review Plan (SRP) Section 2.5.2, " Vibratory Ground Motion." The controlling 36 earthquakes for this path are determined as illustrated in Figure 2. The 2
1 l l l initial step along PA is to e . duct an Electric Power Research Institute D2 1 (EPRI) or a Lawrence Livermore National Laboratory (LLNL) seismic hazard ) 3 assessment of the site (EPRI-NP-6395-D, Ref.1, and NUREG/CR-5250, Ref. 2) for J 4 Eastern U.S. sites. The results of this assessment are compared to the I 5 collective assessments of the currently operating plants as described in 6 Appendix B of this guide. The site seismic hazard assessments are ! 7 deaggregated as described in Appendix C of this guide to obtain the 8 controlling earthquakes for PA. Ground motion based on the controlling 9 earthquakes from PA are also calculated as described in SRP 2.5.2. The ground 10 motions from the DA and PA controlling earthquakes are compared to the SSE 11 ground motion or are used to develop the SSE. 12 13 1. IDENTIFICATION AND CHARACTERIZATION OF SEISMIC SOURCES 14 15 " Seismic source" is a general term referring to both seismogenic sources 16 and capable tectonic sources. A "seismogenic source" is a portion of the 17 earth that is considered to have uniform seismicity (same DSE and frequency of 18 recurrence). A seismogenic source would not cause surface displacement. 19 Seismogenic sources cover a wide range of possibilities from a well-defined 20 tectonic structure to simply a large region of diffuse seismicity (seismotec-21 tonic province). A " capable tectonic source" is a tectonic structure that can 22 generate both earthquakes and deformation such as faulting or folding at or 23 near the surface in the present tectonic regime. Appendix A contains 24 definitions of these and other terms used in this regulatory guide. 25 Investigations of the site and region around the site are necessary to 26 identify seismic sources and determine their potential for generating earth-27 quakes and causing surface deformation. Identification and characterization 28 of seismic sources are based on regional and site geological and geophysical
- 9 data, historical and instrumental seismicity data, the regional stress field, 30 and geologic evidence for prehistoric earthquakes. The bases for the identi-31 fication of the seismic sources should be documented. Appendix 0 describes 32 investigation procedures that may be used in identifying and defining seismic 33 sources.
34 The following is a general list of characteristics to be determined for a 35 seismic source: 36 37
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1 1. Source zone geometry (location and extent, both surface and subsurface). 2 I 3 2. Description of Quaternary (last 2 million years) displacements (sense of 4 slip on the fault, fault length and width, age of displacements, esti-5 mated displacement per event, estimated magnitude per offset, rupture 6 length and area, and displacement history or uplift rates of seismogenic 7 folds). 8 9 3. Historical and instrumental seismicity associated with each source. 10 11 4. Evidence of paleoseismicity. 12 13 5. Relationship of the fault to other potential seismic sources in the 14 region. 15 16 6. Deterministic Source Earthquake. (Details for the determination of the 17 DSEs are provided in section 2.)
- 7. Recurrence model (frequency of earthquake occurrence versus magnitude).
l 20 21 8. Effects of human activities such as withdrawal of fluid from or addition l 22 of fluid to the subsurface, extraction of minerals, or the effects of ) 23 dams or reservoirs. l 24 I 25 9. Volcanism. Volcanic hazard is not addressed in this regulatory guide. l 26 It will be considered on a case by case basis in regions where this l 27 hazard exists. 28
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29 10. Other factors that can contribute to the characterization of seismic 30 sources such as strike and dip of tectonic structures, orientations of i 31 regional and tectonic stresses, fault segmentation (both along strike and 32 down-dip). 33 34 The level of detail for investigations around the site is governed by the i 35 Quaternary tectonic regime and the geological complexity of the site and ; 36 region. Regional investigations such as geological reconnaissances and , 37 literature reviews should be conducted within a radius of 320 km (200 miles) l l 4 i
I 1 of the site to identify seismic sources. Geological, seismological, and ! D2 3 geophysical investigations should be carried out within a radius of 40 km (25 miles) to identify and characterize the seismic and surface deformation poten-4 tial of capable tectonic sources and the seismic potential of seismogenic 5 sources, or to demonstrate that such structures are not present. Detailed 6 geological, geotechnical, seismological, and geophysical investigations should 7 be conducted within a radius of 8 km (5 miles) of the site to determine the 8 potential for tectonic deformation at or near the ground surface in the site 9 vicinity. Sites that are located such that there are capable or seismogenic 10 structures within a radius of 40 km (25 miles) should have more extensive geo-11 logic and seismic investigations and analyses (similar to those within a 8 km 12 (5 mile) radius). The areas of investigations may be asymmetrical and larger 13 than specified above in areas near capable tectonic sources, high seismicity, 14 or complex geology. 15 For the site and the area surrounding the site, the lithologic, strati-16 graphic, hydrologic, and structural geologic conditions will need to be deter-17 mined. The investigations should include the determination of the static and 18 dynamic engineering properties of the materials underlying the site and an i 19 evaluation of physical evidence concerning the behavior during prior earth-20 quakes of the surficial materials and the substrata underlying the site. The 21 properties needed to determine the behavior of the underlying material during 22 earthquakes and the characteristics of the underlying material in transmitting 23 earthquake ground motions to the foundations of the plant (such as seismic 24 wave velocities, density, water content, porosity, elastic moduli, and 25 strength) should be determined. Geological, seismological, and geophysical 26 investigations are described in Appendix D to this guide and geotechnical 27 investigations are described in Regulatory Guide 1.132, " Site Investigations 28 for Foundations of Nuclear Power Plants." 29 Where it is determined that surface deformation need not be taken into 30 account, sufficient data to clearly justify the determination should be pre-31 sented. Because engineering solutions cannot always be demonstrated for the 32 effects of permanent ground displacement phenomena, it is prudent to avoid a 33 site that has a potential for surface deformation. 34 35 5
1 Eastern United States 2 3 The area east of the Rocky Mountains within the North American Plate and ) 4 well away from the active plate margins is described as the " stable conti-5 nental region" (SCR). In the SCR, characterization of seismic sources is more 6 problematic than in the active plate margin region because there is generally 7 no clear association between seismicity and known tectonic structures. The ' 8 observed geologic structures were generated in response to tectonic forces 9 that no longer exist and that bear little correlation with current tectonic 10 fprces. Thus, more judgment must be used than for active plate margin l 11 regions, and it is important to account for this uncertainty by the use of 12 alternative models. 13 Based on current knowledge, seismic sources in the SCR are generally I 14 relatively large areas, or seismotectonic provinces. The identification of 15 seismic sources in the SCR considers hypotheses presently accepted for the 16 occurrence of earthquakes in the SCR (for example, the reactivation of favor-17 ably oriented zones of weakness or the local amplification and release of 18 stresses concentrated around a geologic structure). 19 20 Western United States 21 22 For the active plate margin region, where earthquakes can often be 23 correlated with tectonic structures, those structures should be assessed for 24 their seismic and surface deformation potential. In the Western United 25 States, at least three types of sources exist: (1) faults that are known at 26 the surface, (2) buried (blind) sources and, (3) subduction zone sources, such 27 as exist in the Pacific Northwest. The nature of surface faults can be deter-28 mined by conventional surface and near-surface investigation techniques to 29 determine strike, geometry, sense of displacements, length of rupture, 30 Quaternary history, etc. 31 Buried (blind) faults are often accompanied by coseismic surficial 32 deformation such as folding, uplift, or subsidence. The surface expression of 33 blind faulting can be detected by the mapping of uplifted or down-dropped geo-34 morphological features or stratigraphy, survey leveling, and geodetic methods. 35 The nature of the structure at depth can often be determined by core borings 36 and geophysical techniques. 6
1 Subduction zones are seismic sources in the Pacific Northwest and Alaska, i 2 The seismic sources associated with subduction zones are the interface between 3 the subducting and overriding lithospheric plates, faults within the 4 overriding plates, and intraslab sources in the interior of the downgoing I 5 oceanic slab. The characterization of subduction zone seismic sources should 6 include consideration of the geometry of the subducting plate, rupture 7 segmentation df subduction zones, the geometry of historical ruptures, 8 constraints on the up-dip and down-dip extent of rupture, and comparisons with ! 9 other subduction zones worldwide. 10 11 2. DETERMINISTIC SOURCE EARTH 0VAKES (DSES) 12 13 DSEs are the largest earthquakes that can reasonably be expected to occur 14 in a given seismic source in the current tectonic regime. Deterministic 15 source earthquakes are characterized by their magnitudes and, as a minimum, 16 will be the largest historical earthquake associated with each source. A l 17 larger earthquake is warranted when specific geological evidence is available,
~18 e.g., paleoliquefaction evidence of larger prehistoric earthquakes or when the l 19 rate of occurrence of earthquakes indicates the likelihood of a larger 20 earthquake than the largest historical event.
21 l 22 Eastern United States 23 24 In the SCR there is a short record of the historical seismicity and 25 considerable uncertainty about the underlying cause; of earthquakes. Because 26 of this uncertainty, it is necessary to use considerable judgment and a 27 variety of approaches to establish the DSEs. In addition to the maximum his-28 torical earthquake, the determination of the DSE earthquake for each identi-29 fied seismogenic source is based on the pattern and rate of seismic activity, 30 the Quaternary (2 million years and younger) development and characteristics 31 of the source, the current stress regime and how it aligns with the known 32 tectonic structures in the source, and paleoseismic data. 33 34 Western United States 35 I 36 In the Western United States, earthquakes can eften be associated with 37 tectonic structures. For faults, the magnitude of an earthquake is related to 7
1 the characteristics of the estimated rupture, such as the length or the amount 2 of fault displacement. The following empirical correlations can be used to { 3 estimate DSEs from fault behavioral data and also to predict the amount of 4 displacement that might be expected for a given magnitude. 5 6 1. Surface rupture length versus magnitude (Refs. 3-6). 7 8 2. Subsurface rupture length versus magnitude (Ref. 7). 9 10 3. Rupture area versus magnitude (Ref. 8). 11 12 4. Maximum and average displacement versus magnitude (Ref. 9). 13 14 In the Pacific Northwest and Alaska. DSEs must be assessed for subduction 15 zone seismic sources. Worldwide observations indicate that the largest earth-16 quakes are associated with the plate interface, although intraslab earthquakes 17 (e.g., the 1949 Puget Sound earthquake) can also be large. DSEs for subduc-18 tion zone sources can be based on estimates of the expected dimensions of rupture or analogies to other subduction zones worldwide. 21 3. PROBABILISTIC SEISMIC HAZARD ANALYSIS 22 23 A probabilistic seismic hazard analysis (PSHA) should be carried out for 24 the site. A PSHA allows the use of multi-valued models to estimate the like-25 lihood of earthquake ground motions occurring at a site. The PSHA systemati-26 cally takes into account uncertainties that exist in various parameters (such 27 as seismic sources, maximum earthquakes, and ground motion attenuation). 28 Alternative hypotheses are considered in a quantitative fashion. The PSHA can 29 be used to determine the effects of varying significant parameters, to iden-30 tify significant sources in terms of magnitude and distance, and to provide 31 hazard estimates for use in seismic probabilistic risk assessments. 32 The results of a PSHA are specifically used to derive controlling earth-33 quakes as discussed below and in Appendix C. It can also be used to estimate 34 the annual probability of exceeding the SSE and demonstrate that the annual l 35 probability of exceeding the SSE design ground motion at the site compares 36 favorably with that for the currently operating nuclear power plants. (The 37 procedure for this demonstration is described in Appendix B.) 8
1 Either the Lawrence Livermore National Laboratory (LLNL) (Ref. 2) or 2 Electric Power Research Institute (EPRI) (Ref.1) seismic hazard analyses, 3 including associated data bases, should be used for plant sites in the SCR. 4 However, alternative seismic hazard analyses may be used with proper justifi-5 cation. For the PSHA, use of the seismic sources identified in the LLNL and 6 EPRI studies is considered acceptable except in regions of the SCR with high 7 activity rates, e.g., near New Madrid and Charleston. In these cases, either 8 describe additional site-specific seismic sources or show that the regional 9 seismic sources in the LLNL and EPRI probabilistic studies adequately model 10 the tectonics in the vicinity of the site. 11 Probabilistic methodologies similar to the LLNL and EPRI seismic 12 hazard studies have not been performed for the Western United States. For 13 Western U.S. sites, a site-specific PSHA must be performed and documented in 14 such detail that a thorough review can be carried out by the NRC staff 15 (Refs. 10-12). 16 17 4. CONTROLLING EARTH 0VAKES 18
)19 Controlling earthquakes are those earthquakes that have the greatest 20 effect on the ground motion at the nuclear power plant site. There may be 21 several controlling earthquakes for a site, e.g., a moderate nearby earthquake 22 may control the high-frequency portion of the ground motion spectrum, and a 23 large distant earthquake may control the low-frequency portion of the 24 spectrum. See Figure 2.
25 In the Deterministic Analysis (Figure 1), the controlling earthquakes are 26 determined by the following procedure. 27 28 1. For each seismic source, place the DSE at the closest approach of that 29 source to the site. For the seismic source in which the site is located, 30 the DSE should be considered to occur at about 15 km (9 mi) from the 31 site. 32 33 2. Determine the DSEs that produce the largest ground motions at the site. 34 Ground motions at the site from DSEs are estimated using the procedures o 35 described in Standard Review Plan Section 2.5.2, " Vibratory Ground
)36 Motion." The earthquakes producing the largest ground motions at the 37 site are the controlling earthquakes.
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1 In the Probabilistic Analysis (see Figure 1), the controlling earthquakes 2 are determined by the following procedure. 3 4 1. Perform a probabilistic seismic hazard analysis for the site. The 5 analysis will develop uniform hazard spectra at several annual 6 probabilities of exceedence. 7 8 2. Deaggregate the probabilistic seismic hazard analysis results to identify 9 controlling earthquakes; their description includes magnitude (H) and 10 distance (D) from the site (see Appendix C). This deaggregation should 11 be done at the annual probability of exceedence level discussed in 12 Appendix B. 13 14 The controlling earthquakes thus derived from the deterministic and 15 probabilistic analyses can be compared at this stage to determine whether the 16 controlling earthquakes from these two approaches are similar and also to 17 determine if the controlling earthquake or earthquakes that will dominate the 18 ground motion estimates at the site are easily identifiable. If the dominant 19 controlling earthquake can be identified, the ground motions are determined { 20 only for this identified controlling earthquake. If the controlling earth-21 quakes from the two approaches are dissimilar, ground motion estimates are 22 made for various controlling earthquakes and compared to derive the final 23 ground motion estimates for use in establishing the SSE ground motion or 24 comparing it with the SSE ground motion. 25 26 C. REGVLATORY POSITION 27 28 1. During the site selection phase, the preferred sites are those with a 29 minimum likelihood of surface or near-surface deformation or the occur-30 rence of earthquakes on faults in the site vicinity (within a radius of 8 31 km (5 miles)). Because of the uncertainties and difficulties in mitigat-32 ing the effects of permanent ground displacement phenomena such as sur-33 face faulting or folding, fault creep, subsidence or collapse, the NRC 34 staff considers it prudent to select an alternative site when the 35 potential for permanent ground displacement exists at a site. 36 10
1 2. Regional investigations such as geological reconnaissances and 2 literature reviews should be conducted within a radius of 320 km (200 3 miles) of the site to identify seismic sources. 4 5 3. Geological, seismological, and geophysical investigation should be 6 carried out within a radius of 40 km (25 miles) to identify and charac-7 terize the seismic potential of capable tectonic and seismogenic sources 8 or demonstrate that such structures are not present. 9 10 4. Detailed geological, geotechnical, seismological, and geophysical 11 investigations should be conducted within a radius of 8 km (5 miles) of 12 the site to determine the potential for tectonic deformation at or near 13 the ground surface in the site vicinity. Geological, seismological, and 14 geophysical investigations are described in Appendix 0 to this guide, and 15 geotechnical investigations are described in Regulatory Guide 1.132, 16 " Site Investigations for Foundations of Nuclear Power Plants." 17 18 5. Sites that are located such that there are capable or seismogenic faults 19 within a radius of 40 km (25 miles) should have more extensive geologic 20 and seismic investigations and analyses (similar to those within an 8-km 21 (5-mile) radius). The area of investigation may be asymmetrical and 22 extend beyond 40 km (25 miles). 23 24 6. Seismic sources that were not considered in the LLNL or'EPRI PSHA should 25 be identified and characterized using the information developed by the 26 investigations. Alternative seismic sources should be developed to 27 incorporate a range of interpretations, and the bases for the l 28 identification of these sources should be documented. Source zone 29 geometry should be defined for each seismic source. For faults, the type 30 of slip, length of rupture, amount of displacement per maximum event, and 31 area of the rupture surface should be determined. 32 33 7. Deterministic source earthquakes, which are the best judgment of the 34 maximum earthquake that can reasonably be expected to occur in a given 35 seismic source, should be defined for each seismic source. 36 11
1 1 8. A PSHA for the site should be performed to estimate the annual 2 probability of exceeding the SSE. Either the LLNL or EPRI probabilistic , 3 seismic hazard analyses with associated data bases should be used for 4 plants in the Eastern United States. For western plants, a site-specific ! 5 PSHA should be performed. Use the PSHA to identify sources in terms of ) 6 magnitude and distance that contribute significantly to the seismic l 7 hazard at the site, i 8 9 9. Determine the CEs that produce the largest ground motions at the site. 10 Ground motions at the site from CEs are estimated using the procedures j 11 described in Section 4 of the Discussion section of this guide and l 12 Standard Review Plan Section 2.5.2, " Vibratory Ground Motion." l 13 14 D. IMPLEMENTATIOE 15 16 The purpose of this section is to provide guidance to applicants and 17 licensees regarding the NRC staff's plans for using this regulatory guide. 18 This draft guide has been released to encourage public participation in 19 its developcent. Except in those cases in which the applicant proposes an , 1 20 acceptable alternative method for complying with the specified portions of the ' 21 Commission's regulations, the method to be described in the active guide 22 reflecting public comments will be used in the evaluation of applications for 23 construction permits, operating licenses, early site permits, or combined 24 licenses submitted after the implementation date to be specified in the active 25 guide. This guide would not be used in the evaluation of an application for 26 an operating license submitted after the implementation date to be specified 27 in the active guide if the construction permit was issued prior to that date. 28 29 O 12
l l 1 REFERENCES 2 3 1. Electric Power Research Institute, "Probabilistic Seismic Hazard Evalua-4 tions at Nuclear Power Plant Sites in the Central and Eastern United 5 States: Resolution of the Charlesten Earthquake Issue," NP-6395-D, April 6 1989. 7 8 2. D. L. Bernreuter et al., " Seismic Hazard Characterization of 69 Nuclear 9 Plant Sites East of the Rocky Mountains," NUREG/CR-5250, January 1989, 10 11 3. D. B. Slemmons, " Faults and Earthquake Magnitude," U.S. Army Corps of 12 Engineers, Waterways Experiment Station, Misc. Papers S-73-1, Report 6, 13 1977. 14 15 4. D. B. Slemmons, " Determination of Design Earthquake Magnitudes for 16 Microzonation," Proceedinas of the Third International Microzonation 17 Conference, Volume 1, pp. 119-130, 1982. 18 19 5. M. G. Bonilla, H.A. Villabobos, and R.E. Wallace, " Exploratory Trench 20 Across the Pleasant Valley Fault, Nevada," Professional Paper 1274-B, 21 U.S. Geological Survey, pp. B1-B14,1984. 22 23 6. S. G. Wesnousky, " Relationship Between Total Affect, Degree of Fault 24 Trace Complexity, and Earthquake Size on Major Strike-Slip Faults in 25 California" (Abs), Seismaloaical Research Letters, Volume 59, Number 1, 25 1988. 27 { 28 7. D. L. Wells et al., "New Earthquake Magnitude and Fault Rupture Para-29 meters: Part II. Maximum and Average Relationships" (Abs), Seismoloaical ! 30 Research letter.1, Volume 60, Number 1, 1989. 31 32 8. M. Wyss, " Estimating Maximum Expectable Magnitude of Earthquakes from 33 Fault Dimensions," Geoloav, Volume 7 (7), pp. 336-340,1979. 34 35 9. D. L. Wells and K. J. Coppersmith, " Analysis of Empirical Relationships 36 Among Magnitude, Rupture Length, Rupture Area, and Surface Displacement" 37 (Abs), Seismoloaical Research Letters, Volume 63, Number 1,1992. 13
1 10. Pacific Gas and Electric Company, " Final Report of the Diablo Canyon Long 2 Term Seismic Program; Diablo Canyon Power Plant," NRC Docket Nos. 50-275 3 and 50-323, 1988.* 4 5 11. USNRC, " Safety Evaluation Report Related to the Operation of Diablo 6 Canyon Nuclear Power Plant, Units 1 and 2," NUREG-0675, Supplement 7 No. 34, June 1991. 8 9 12. Letter from G. Sorensen, Washington Public Power Supply System, to USNRC. l 10
Subject:
Nuclear Project No. 3, Resolution of Key Licensing Issues,
)
11 Response to Question on Seismic Hazard, February 29, 1988.* l 12 9 l l l l l 1 13 14
*Available for inspection or copying for a fee at the NRC Public Document Room, 2120 L Street NW., Washington, DC.
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PROBABILISTIC SITE DETERMINISTIC g3 ANALYSIS (PA) ANALYSIS (DA) o E* Geological, Selsmological g and GeophysicalInvestigations A i
, I I Conduct an EPRI or LLNL Identify Seismic
[ 3. Selsmic Hazard Assessment Sources U 5, Compare to Operating Determine Deterministic Source 8 Plants to set Probability Earthquakes for Each Source of Exceedance Level G m
$ Determine Controlling Determine Controlling
- Earthquakes (CEs) Ms & Ds Earthquakes (CEs) Ms & Ds
. i e n E Compara CEs Derived m From PA and DA 3 Develop SSE Ground Motion c- ._( GM) or Compare with CE GMs 3.
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1
} A_EPENDIX A 3 DEFINITIONS 4
5 A goable tectonic source is a tectonic structure that can generate both 6 earthquakes and tectonic surface deformation such as faulting or folding at or 7 near the sur S m in the present seismotectonic regime. It is characterized by 8 at least one of the following characteristics: 9 10 a. Presence of surface or near-surface deformation of landforms or geologic 11 deposits of a recurring nature within the last approximately 500,000 12 years or at least once in the last approximately 50,000 years. 13 14 b. A reasonable association with one or more large earthquakes or sustained 15 earthquake activity, usually accompanied by significant surface 16 deformation. 17 18 c. A structural association with a capable tectonic source having charac-19 teristics of a of this paragraph, such that movement on one could be 20 reasonably expected to be accompanied by movement on the other. 21 22 In some cases, the geologic evidence of past activity at or near the 23 ground surface along a particular capable tectonic source may be obscured at a 24 particular site. This might occur, for example, at a site having a deep over-25 burden. For these cases, evidence may exist elsewhere along the structure 26 from which an evaluation of its characteristics in the vicinity of the site 27 can reasonably be based. Such evidence should be used in determining whether 28 the structure is a capable tectonic source within this definition. 29 Notwithstanding the foregoing paragraphs, structural association of a 30 structure with geologic structural features that are geologically old (at 31 least pre-Quaternary) such as many of those found in the eastern region of the 32 United States will, in the absence of conflicting evidence, demonstrate that 33 the structure is not a capable tectonic source within this definition. 34 35 Contro11ina earthauakes (CEs) are the earthquakes that produce the 36 1argest estimated ground motions at the site. There may be several CEs for a 37 site. A-1
1 A deterministic source earthauake (DSE) is the largest earthquake that 2 can reasonably be expected to occur in a given seismic source in the current { 3 tectonic regime, and it is used in a deterministic analysis. It is generally 4 based on the maximum historical earthquake associated with that seismic 5 source, unless geological evidence warrants a larger earthquake or the rate of 6 occurrence of earthquakes indicates the likelihood of larger than the largest 7 historical event. 8 9 The intensity of an earthquake is a measure of its effects on humans, 10 human-built structures, and the earth's surface at a particular location. 11 Intensity is described by a numerical value on the Modified Mercalli scale. 12 13 An earthquake maanitude is a measure of the strength of an earthquake as 14 determined by seismographic observations. 15 16 Nontectonic deformation is distortion of surface or near-surface soils or 17 rocks that is not directly attributable to tectonic activity. Such deforma-18 tion includes features associated with subsidence, karst terrane, glaciation 19 or deglaciation, and growth faulting. q 20 21 The safe shutdown earthauake around motion (SSE) is the vibratory ground 22 motion for which certain structures, systems, and components are designed to 23 remain functional. 24 25 A seismic so r.a is a general term referring to both seismogenic sources 26 and capable tec'.onic sources. 27 28 A seismoaenic source is a portion of the earth that has uniform earth-29 quake potential (same expected maximum earthquake and frequency of recurrence) 30 distinct from the surrounding area. A seismogenic source will not cause sur-31 face displacement. Seismogenic sources cover a wide range of possibilities 32 from a well-defined tectonic structure to simply a large region of diffuse 33 seismicity (seismotectonic province) thought to be characterized by the same 34 earthquake recurrence model. A seismogenic source is also characterized by 35 its involvement in the current tectonic regime as reflected in the Quaternary 36 (approximately the last 2 million years). 37 A-2
1 A stable continental reaion (SCR) is composed of continental crust, 2 including continental shelves, slopes, and attenuated continental crust, and 3 excludes active plate boundaries and zones of currently active tectonics 4 directly influenced by plate margin processes. It exhibits no significant 5 deformation associated with the major Mesozoic-to-Cenozoic (last 240 million 6 years) orogenic belts. It excludes major zones of Neogene (last 25 million 7 years) rifting, volcanism, or suturing. 8 9 A tectonic Structure is a large-scale dislocation or distortion usually 10 within the earth's crust. Its extent is on the order of miles. 11 12 13 l 1 l l A-3
1 APPENDIX B 3 ACCEPTANCE CRITERIA FOR THE ANNUAL PROBABILITY 4 I 0F EXCEEDENCE LEVEL FOR SAFE SHUTDOWN EARTH 0VAKE 5 GROUND MOTIONS 6 , 7 B.1 INTRODUCTION 8 9 This appendix outlines a procedure to calculate the annual probability of 10 exceeding the safe shutdown earthquake ground motion (SSE). This procedure 11 can be used (1) to compare the calculated annual probability of exceeding the 12 SSE at proposed plants to the calculated annual probabilities for the cur-13 rently operating plants as required by Appendix B to 10 CFR Part 100 and 14 (2) to establish controlling earthquakes in the probabilistic hazard analysis 15 as discussed in Appendix C to this regulatory guide. Uniform hazard spectra 16 (spectra that have a uniform probability of exceedence over the frequency 17 range of interest) should be calculated to estimate the annual probability of 18 exceeding the SSE design response spectrum. D19 20 B.2 PROCEDURE l 21 22 The following procedure is one approach acceptable to the NRC staff to 23 assure that the annual probability of exceeding the SSE compares favorably 24 with that for the nuclear power plants operating as of the date of the final 25 version of Appendix B to Part 100. 26 27 B.2.1 Eastern U.S. Sites 28 I 29 There are two state-of-the-art approaches (outlined in Refs. IB and 2B) 30 currently available to calculate the probabilistic seismic hazard for sites 31 east of the Rocky mountains (Eastern United States). These approaches, how-32 ever, produce different hazard estimates for a given site. Therefore, the NRC 33 staff is recommending the following interim procedure until the differences 34 between the two hazard methods are resolved. This procedure relies on rela-g 35 tive measures to ensure that the annual probability of exceeding the SSE is 36 comparable to that of operating plants. The procedure is based on studies 37 conducted for the Eastern Seismicity Issue and the IPEEE program (Ref. 3B). B-1
1 Either the LLNL or EPRI methodology can L'e used to carry out the following 2 calculations, with the appropriate set of limits associated with each method. 3 If any analysis other than the LLNL or EPRI methods is used in the Eastern 4 United States, annual probabilities of exceeding the SSE would need to be 5 developed for all operating plant sites in addition to the site under 6 consideration in order to make the appropriate comparison. 7 8 Step 1. Calculate the Uniform Hazard Response Spectra (UHRS) with various 9 return periods. Figure B.1 shows a sample set of median UHRS for 10 various return periods. The UHRS should be deveivped at the same 11 location as the location of the SSE -(i.e. either at the free ground 12 surface or at a hypothetical rock outcrop). 13 14 Step 2. Calculate composite annual probabilities of exceeding the SSE and 15 compare those probabilities with operating plants u:,ing median 16 hazard estimates. (Although the median estimates are used for 17 carrying out the procedure outlined in this appendix, the hazard 18 analysis should be performed with consideration of uncertainties to 19 develop complete insights.) The procedure is illustrated in Figure 20 B.2. 21 22 1. Estimate the annual probabilities of exceeding the SSE spectrum 23 at two discrete frequencies (5 and 10 Hz) using the UHRS. 24 l 25 2. Calculate the composite annual probability using the following l 26 formula: 27 28 Composite Annual Probability = 1/2(al) + 1/2(a2) 29 30 where al and a2 represent annual probabilities of exceeding SSE 31 spectral ordinates at 5 and 10 Hz, respectively. 32 33 Examole: From Figure B.2, for a median UHRS derived using the 34 LLNL methodology, at points al and a2 corresponding to 5 and 10 35 Hz: 36 37 B-2
1 Composite Annual Probability - 1/2(4E-5) + 1/2(8E-5) 2 - 6E-5. 4 3. Figure B.3 shows the distribution of median annual probabili-5 ties of exceeding SSEs for operating Eastern U.S. plants using 6 LLNL hazard estimates. This figure also indicates a limit; 7 approximately 50% of the currently operating plants have an 8 annual probability of exceeding the SSE ground motion below 9 this limit. (Limits for both the current EPRI and LLNL seismic 10 hazard studies are listed in Table B.1.) The SSE is adequate 11 when the annual probability of exceed'.ng the SSE compares 12 favorably to the limits shown in these figures. 13 14 Table B.1 15 16 , 17 Method Annual Probability of Exceedance Limits for Median Hazard Estimates 18 LLNL J-4 19 EPRI 3'i-5 20 21 22 For the hypothetical example, the calculated annual probability 23 of exceedance of 6E-5 is less than the limit of IE-4, and thus 24 the probability of exceeding the SSE compares .avorably with 25 that of operating plants. 26 27 Figure B.4 presents the same information from the use of the 28 EPRI UHRS estimates. This limit should be used when the EPRI l'9 method is used to calculate the annual probability of exceeding I 10 the SSE. 31 32 B.2.2 Western U.S. Sites 33 34 For the Western U.S. sites, a probabilistic data base, such as that 35 compiled in the LLNL and EPRI studies, is not available. To date no procedure 36 exists to compare the annual probability of exceeding the SSE to other sites B-3
1 in the Western United States. In addition, the probabilistic hazard at a site 2 in the Western United States may be governed by clearly identifiable seismic l 3 sources, such as faults (or folds) observed at the surface that have better 4 defined seismicity characteristics. Therefore, for Western U.S. sites, a 5 site-specific analysis should be developed using suitable methodologies to 6 estimate the annual probability of exceeding the SSE and to identify 7 cignificant contributors to the hazard (Ref. 4B). 8 9 REFERENCES 10 11 18. Electric Power Research Institute, "Probabilistic Seismic Hazard Evalua-12 tions at Nuclear Power Plant Sites in the Central and Eastern United 13 States: Resolution of the Charleston Earthquake Issue," NP-6395-0,1989. 14 15 28. D. L. Bernreuter et al., " Seismic Hazard Chzracterization of 69 Nuclear 16 Plant Sites East of the Rocky Mountains," NUREG/CR-5250, January 1989. 17 18 38. J.T. Chen et al., " Procedural and Submittal Guidance for Individual Plant 19 Examination of External Events (IPEEE) for Severe Accident Vulnerabil-20 ities." USNRC, NUREG-1407, June 1991. 21 22 43. USNRC, " Safety Evaluation Report Related to the Operation of Diablo 23 Canyon Nuclear Power Plant, Units 1 and 2," NL' REG-C675, Supplement l 24 No. 34, June 1991. I 25 I l l i O B-4
i l l 2 i l 3 4 5 ) 6 7 \ 8 .3 , 9 10 11 12 2 . 30 13 14 - 15 . 16 C 3 8 ~ 17 --- t - 18 g 19 y ? 20 e - 21 io - 9CiuaN 9Catoos s 4 22 cuevc s = soooo. vtuts 23 cunvc 4 - sooo. m occ s = 200o. vons 24 csvt 2 = sooo. tons 25 - to ,, .. _
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1 APPENDIX C 2 l 3 DETERMINATION OF CONTROLLING EARTHOUAKES FROM THE 4 PROBABILISTIC ANALYSIS 5 6 C.1 INTRODUCTION 7 8 This appendix outlines a procedure to determine controlling earthquakes 9 from the probabilistic hazards analysis for a site. The ground motions from 10 these controlling earthquakes should be determined following the procedures 11 outlined in Section 2.5.2 (Subsection 2.5.2.6) of the Standard Review Plan. 12 Controlling earthquakes should be determined for the median seismic hazard 13 limit used to satisfy the requirement of Appendix B to 10 CFR Part 100 and 14 discussed in Section C.2 below and Appendix B of this regulatory guide to 15 demonstrate that the annual probability of exceeding the safe shutdown earth-16 quake ground motion (SSE) compares favorably with that of the currently 17 operating nuclear power plants. 18 19 C.2 PROCEDURE 20 21 The following procedure is one approach acceptable to the NRC staff to 22 determine controlling earthquakes from a probabilistic hazards analysis. 23 24 C.2.1 Eastern U.S. Sites 25 26 As discussed in Apnendix B of this regulatory guide, there are two 27 approaches (Refs. IC and 2C) currently available to calculate probabilistic 28 seismic hazards for sites east of the Rocky mountains (Eastern United States). 29 Either of these methods can be used to carry out the following calculations, 30 with the appropriate set of limits associated with each method. 31 32 Step 1. Perform the site-spr:cific hazard analysis using the LLNL or EPRI 33 method and associated data. From this analysis, compute median 34 hazard curves for the average of the 5 and 10 Hz spectral veloci-35 ties, S n .w. That is a curve showing the annual probability of exceeding various levels of the average of the 5 and 10 Hz spectral G 36 37 velocity. C-1
1 Step 2. Using the appropriate annual probability of exceedance level, P, ) 2 (e.g., for the median S .w y3 hazard curve derived from the LLNL 3 method, P, is IE-4 according to Figure 8.3 and Table 8.1 of Appendix 4 B), enter the hazard curve of step 1 at P, to determine the j 5 corresponding spectral velocity. 6 l 7 Step 3. Deaggregate the median of the average of the 5 and 10 Hz hazard
)
8 curves as a function of magnitude and distance by calculating the , 9 contribution to the hazard for all of the earthquakes in a selected 10 set of magnitude and distance bins to determine the relative con-11 tribution to the hazard, H ,ufor each bin centered at magnitude m 12 and distance d. He is the annual probability of exceeding S y(P,) l 13 computed for a bin at magnitude m and distance d. l 14 1 15 Step 4. Con.pute the magnitude of the controlling earthquake for the median l 16 estimate using the contributions Hg computed in Step 3. l 17
)
ll R - E E mH g / I E Hg 20 md md 21 22 23 The distance of the controlling earthquake from the site is , 24 determined from 1 25 1 26 l
$d log D - E E log (d)Hg / E E Hg 29 md l 30 4 31 32 Step 5. Using the same P, and steps 1 through 4 as above, also determine l 33 controlling earthquakes for median spectral response for the average 34 of the 1 and 2.5 Hz spectral responses, and for the median estimates 35 of the peak ground acceleration. l 36 )
37 Step 6. The ground motions corresponding to the controlling earthquakes are ) 38 determined as outlined in Section 2.5.2 (Subsection 2.5.2.6) of the 39 Standard Review Plan. 40 I O C-2
I i ! l \ 1 C.2.2 Western U.S. Sites D2 3 For the Western U.S. sites, a probabilistic data base, such as compiled 4 in the LLNL or EPRI studies, is not available. In a region of active tec-5 tonics, there is less uncertainty about the significant contributors to the ! 6 seismic hazard, and the cor. trolling earthquakes can generally be defined 7 deterministically. For regions of lower, less active tectonics, an analysis l 8 similar to the one outlined above in Steps 1-4 can be performed. Step 1 would 9 be omitted and the Sy level used would correspond to the value selected for 10 the SSE. 11 12 C.3 EXAMPLE FOR EASTERN U.S. SITE 13 14 To illustrate the above procedure, calculations are shown here for cn Eastern 15 U.S. site using the LLNL methodology given in NUREG/CR-5250 (Ref. IC). 16 17 Step 1 is omitted. 1 Step 2. Table C.1 gives the annual probability of exceeding various levels 20 of the average of t h 5 and 10 Hz spectral velocity hazard curves 21 from the LLNL study. 22 23 Table C.1 24 25 Average of 5 and 10 Hz yS Curves for the Site 26 27 Spectral Annual Probability of Exceedance 28 Velc;ity (Median) 29 (Su-cm/s) 30 2 2.6E-3 31 5 3.7E-4 32 10 5.8E-5 33 34 35 Interpolating the annual probability of exceedence (P,) values given in 36 Table B.1 from Table C.1, the corresponding value for S y (P g ) is as given in , 37 Table C.2. ' d 38 C-3
1 Table C.2 2 3 Spectral Velocity (Avg. 5 to 10 Hz) Median 4 Sv(P,)-cm/s 8 5 6 4 7 Step 3. For this example, to deaggregate the hazard and determine the Hg , 8 it is first necassary to compute the contribution to the average I 9 hazard for the 5 and 10 Hz spectral velocities for the matrix of i 10 magnitudes and distance bins such as given in Table C.3. 11 12 Table C.3 13 14 Magnitudes and Distance Bins Used in Example I 15 l 16 Distance Magnitude Range of Bin 17 Range of 18 Bin (km) 5 - 5.5 5.5 - 6 6 - 6.5 6.5 - 7 7 - 7.5 >7.5 19 0-25 20 25-50 21 50-100 22 100-150 23 150-200 24 >200 25 26 27 For each bin, a complete hazard analysis is performed to give the 28 contribution to the hazard from all earthquakes within the bin, e.g., all 29 earthquakes with magnitudes 6 to 6.5 and distance 25 to 50 km from the si'.e. 30 The results for this bin are given in Table C.4. 31 32 O C-4
1 Table C.4 l 2 3 Contribution to the Hazard From all Earthquakes in the Range of 4 6 s M s 6.5 and distances 25 s d s 50 to the average of the 5 5 and 10 Hz Spectral Velocity 6 __ _ 7 Spectral Annual Median 8 Velocity, S y Probability of Exceedance 9 5 1.4E-5 10 _ 10 3.1E-6 11 12.5 1.1E-6 12 13 14 The value of Hu (annual probability of exceedingyS (P,)) for this bin is 15 obtained from Table C.4 using the Sy(P,) values given in Table C.2 and comput-e 16 ing Hg by interpolation. The values for Hg for this bin are given in Table 17 C.S. 18 19 Table C.5 20
) 21 Value for Hg for the Bin 6 s m s 6.5 and 22 25 s d s 50 for the Example Site 23 24 Annual Probability of Exceeding Sy(P,) Median 25 For a Bin 26 H, 5.0E-6 27 28 l 29 Table C.o gives the complete matrix of the H g values for the example l 30 site. l 31 32 l
C-5
lable C.6 3 Hg Values for All Bins Based on the Median Hazard i 4 (Note: If Hg s 1.E-10, it is listed as 0.) l 5 l 6 Distance Magnitude Range of Bin
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5 - 5.5 5.5 - 6 6 - 6.5 6.5 - 7 7 -7.5 >7.5 8 0-25 2.0E 1.lE-5 2.4E-6 0 0 0 9 25-50 6.2E-6 8.9E-6 5.0E-6 6.5E-9 0 0 10 50-100 6.0E-7 2.3E-6 6.8E-6 8.4E-7 0 0 11 100-150 1.6E-9 1.6E-7 1.5E-6 2.8E-6 0 0 12 150-200 0 1.lE-9 2.lE-8 4.6E-7 0 0 ! 13 >200 0 0 0 6.0E-9 0 0 14
}5 Step 4. To compute R, D for the example site, the values of Hg given in 17 Table C.6 are used with m and d values corresponding to the midpoint 18 of the magnitude of the bin (5.25, 5.75, 6.25, 6.75, 7.25, 7.75) and l 19 centroid of the ring area (16.7, 38.9, 77.8, 126, 176 and somewhat 20 arbitrarily 300 km).
21 33 Thus for the example site, the controlling earthquakes, in 8, D 24 values, are given in Table C.7. 25 26 Table C.7 27 28 Magnitude and Distance of Controlling Earthquake From the 29 LLNL Probabilistic Analysis 30 31 Based on Median Hazard Estimates s8 ll R 32 i D ( i Controlling earthquakes for other frequency ranges (Step 5 of C.2.1) are 41 calculated by repeating the above four steps.
- " 9 C-6
1 C.4 EXAMPLES FOR WEST 1RN U.S. SITES 2 I 3 Since a general approach for the Western U.S. sites is not available, two 4 specific cases illustrating determination of controlling earthquakes are _ 5 discussed below. 6 7 C.4.1 - Diablo Canyon I 8 9 The Diablo Canyon site is located on the California coast. A logic tree ! 10 approach has been used to assign weights to variables associated with faults 11 near the site and determine maximum magnitude distributions (Ref. 3C). The i 12 logic tree approach was also part of the probabilistic seismic hazard anal- ] l 13 ysis. The result was that the Hosgri fault zone was the most significant 14 source. The controlling earthquake for the Diablo Canyon site is a magnitude 15 7.2 event on the Hosgri fault zone at the closest distan'ce of this fault zone 16 to the site (4.5 km). The controlling earthquake magnitude is larger than the 17 maximum historical earthquake (the 1927 magnitude 7.0 Lompoc earthquake), 18 which mav he e occurred on a structure related to the Hosgri. 19
}
20 C.4.f - WNP-3 21 ) 22 The WNP-3 site is located in western Washington and lies above the 23 Cascadia subduction zone. The staff considered four controlling earthquakes 24 for the site (Ref. 4C): 25 26 1. The applicant proposed that a maximum random earthquake in the crust near 27 the site is magnitude 5-1/2 to 6. This earthquake is based on the , 28 1argest historical earthquakes in the Coastal Plain seismotectonic pro-( 29 vince (about magnitude 5) and the resolution of geological studies in the ! 30 site region. 31 32 2. The maximum earthquake associated with the Olympia Lineament, which is j 33 35 km northeast of the site, is a magnitude 7.5 based on estimated 34 maximum rupture length. 35 36 3. The maximum magnitude earthquake for the intraslab subduction zone source j ! 37 is about magnitude 7-1/2, based on the maximum historical event C-7
l l 1 associated with the Cascadia subduction zone intraslab source (the 1949 1 2 magnitude 7.1 Puget Sound earthquake) and comparisons with intraslab 3 sources in other subduction zones worldwide. 4 5 4. The interface subduction zone source is capable of great (larger than ) 6 magnitude 8) earthquakes. This maximum magnitude is still under review 7 in light of ongoing geological studies. At this time, the staff consid-8 ers the maximum magnitude to be 8-1/4, based on arguments about the 9 likely dimensions of rupture and comparisons with other subduction zones 10 with slow convergence rates. I 11 12 REFERENCES 13 , 14 10. D. L. Bernreuter et al., " Seismic Hazard Characterization of 69 Nuclear 15 Plant Sites East of the Rocky Mountains," NUREG/CR-5250, January 1989. 16 17 2C. Electric Power Research Institute, "Probabilistic Seismic Hazard Evalua-18 tions at Nuclear Power Plant Sites in the Central and Eastern United 19 States: Resolution of the Charleston Earthquake Issue," NP-6395-D,1989. 20 21 3C. " Safety Evaluation Report Related to the Operation of Diablo Canyon 22 Nuclear Power Plant, Units 1 and 2," NUREG-0675, Supplement No. 34, June 23 1991. 24 25 4C. Letter from Marvin Mendonca, NRC, to D.W. Mazur, Washington Public Power 26 Supply System, "NRC Review of Seismic Report for WNP-3," January 4, 27 1991.* i 28 29 30 *Available for inspection or copying for a fee in the NRC Public Document Room, 31 2120 L Street NW., Washington, DC. C-8
l
)
1 APPENDIX D 2 GEOLOGICAL. SEISM 01.0GICAL. AND GEOPHYSICAL INVESTIGATIONS TO 3 CHARACTERIZE SEISMIC SOURCES 4 5 D.1 INTRODUCTION 6 7 Seismic sources are areas where future earthquakes are likely to occur. 8 Gological and seismological investigations provide the information needed to 9 characterize source parameters, including the size and geometry of the seismic 10 sources, earthquake recurrence models, and deterministic source earthquakes 11 (DSE). The amount of data available about earthquakes and their causative 12 sources varies substantially between tha Western U.S. and the stable conti-13 nental region (SCR), and also from region to region within these broad areas. 14 In active tectonic regions, the focus will be on the identification of both 15 capable tectonic sources and seismogenic sources, and the methods described in 16 Section D.2 of this appendix can be applied. In the SCR east of the Rocky 17 Mountains, seismogenic sources play a significant role because of the diffi-18 culty in unequivocally correlating earthquake activity with known tectonic 19 structures. 20 In the SCR a number of significant tectonic structures exist that have 21 been suggested as potential seismogenic sources (e.g., the New Madrid fault - 22 zone, Nemaha Ridge, Meers fault, Ramapo fault zone, Clarendon-Linden fault). 23 There is no clear procedure to follow to characterize the DSE magnitude asso- s 24 ciated with such possible seismogenic sources; therefore, it is most likely 25 that the determination of the seismogenic nature of the source will be 26 inferred rather than demonstrated by strong correlations with seism' city 27 and/or geologic data. Furthermore, it is not known what relationn exist 28 between observed tectonic structures in a given seismogenic sou;ce and the 29 current earthquake activity loosely correlated with that source. Generally, 30 the observed tectonic structure resulted from ancient tectonic forces that are 31 no longer present, and thus the structural extent may not be a very meaningful 32 indicator of the size of future earthquakes in the source. Careful analysis 33 of the historical record and the results of regional and site studies and 34 judgment play key roles. If, on the other hand, such strong correlations 35 and/or data exist between seismicity and seismic sources, then approaches used 36 for active tectonic regions can be applied. D-1
1 The following is a general list of characteristics to be determined for a 2 seismic source: 4
- Source zone geometry (location and extent, both surface and subsurface).
5 l i 6
- Description of Quaternary (last 2 million years) displacements (sense of 7 slip on the fault, fault length and width, age of displacements, esti- l 8 mated displacements per event, estimated magnitudes per offset, rupture 9 length and area, and displacement history or uplift rates of seismogenic 10 folds).
11 12
- Historical and instrumental seismicity associated with each source.
13 14
- Paleoseismicity.
15 16
- Relationship of the fault to other potential seismic sources in the 17 region.
18 ,
- Deterministic Source Earthquake.
21
- Recurrence model (frequency of earthquake occurrence versus magnitude).
22 23 . Effects of human activities such as withdrawal of fluid from or addition 24 of fluid to the subsurface, extraction of minerals, or the effects of 25 dams or reservoirs. ; 26 27
- Volcanism. Volcanic hazard is not addressed in this regulatory guide.
28 It will be considered on a case-by-case basis in regions where this 29 hazard exists. l 30 31
- Other factors that can contribute to characterization of seismic sources 32 such as strike and dip of tectonic structures, orientations of regional 1 33 and tectonic stresses, fault segmentation (both along strike and 34 downdip). !
35 36 i D-2
l l 1 D.2. INVESTIGATIONS TO CHARACTERIZE SEISMIC SOURCES I 2 3 0.2.1 General 4 5 Investigations of the site and region around the site are necessary to 6 identify both seismogenic sources and capable tectonic sources and to deter-7 mine their potential for generating earthquakes and causing surface deforma-8 tion. If it is determined that surface deformation need not be taken into 9 account, sufficient data to clearly justify the determination should be 10 presented in the license application or early site review. 11 In the siting of nuclear power plants, engineering solutions are gen-12 erally available to mitigate the potential vibratory effect of earthquakes 13 through design. However, such solutions cannot always be demonstrated as 14 being adequate for mitigation of the effects of permanent ground displacement 15 phenomena such as surface faulting or folding, subsidence, ground collapse, or 16 fault creep. For this reason, it is prudent to select an alternative site 17 when the potential for permanent ground displaceme v exists at the site (Ref. 18 1D). In most of the Eastern United States, tectonic structures at seismogenic 19 depths, as determined from earthquake hypocenters, apparently bear no rela-20 tionship to geologic structures exposed at the ground surface. Young faults 21 either do not extend to the ground surface or there is insufficient geologic 22 material of the appropriate age available to date the faults. Seismogenic 23 faults are not always exposed at ground surface in the Western United States 24 as demonstrated by the buried (blind) reverse sources of the 1983 Coalinga, 25 1988 Whittier Narrows, and 1989 Loma Prieta earthquakes. These factors 26 emphasize the need to not only conduct thorough investigations at the ground 27 surface but also to identify structures at seismogenic depths. 28 The level of detail for investigations should be governed by the current 29 and late Quaternary tectonic regime and the geological complexity of the site 30 and region. Whenever faults or other structures are encountered at a site 31 (including in the SCR) either in outcrop or excavations, it is necessary to 32 perform many of the investigations described below to demonstrate whether or 33 not they are capable tectonic sources. 34 Regional investigations extend to a distance of 320 km (200 mi) from the 35 site, and data are presented at a scale of 1:500,000 or smaller. Investiga-36 tions of greater detail are conducted to a distance of 40 km (25 mi) from the 37 site and the data presented at a scale of 1:50,000 or smaller. Detailed D-3
1 investigations are carried out within a radius of 8 km (5 mi) from the site l 2 and data are presented at a scale of 1:5000 or smaller. Data from investiga-3 tions within the site area (approximately 1 square kilometer) are presented at 4 a scale of 1:500 or smaller. The areas of investigations may be asymmetrical 5 and larger than those described above in regions of late Quaternary activity ! 6 or historical seismic activity (felt or instrumentally recorded data) or where 7 a site is located near a capable tectonic source such as a fault zone. 8 Regional and site information needed to assess the integrity of the site l 9 with respect to potential ground motions and surface deformation caused by 10 capable tectonic sources include determination of (1) the lithologic, strati-11 graphic, geomorphic, hydrologic, geotechnical, and structural geologic charac-l 12 teristics of the site and the area surrounding the site, including its geo-13 logic history, (2) geologic evidence of fault offset or other distortion such 14 as folding at or near the ground surface at or near the site, and (3) whether 15 or not any faults or other tectonic structures, any part of which are within a 16 radius of 8 km (5 mi), are capable tectonic sources. This information will be l 17 used to evaluate tectonic structures underlying the site, whether buried or l 18 expressed at the surface, with regard to their potential for generating earth-19 quakes and for causing surface deformation at or near the site, The evalua-20 tion is to consider the possible effects caused by human activities such as 21 withdrawal of fluid from or addition of fluid to the subsurface, extraction of 22 minerals, or the loading effects of dams or reservoirs. 23 24 0.2.2 Reconnaissance Investiaations. Literature Review. and Other Sources of 25 Preliminary Information 26 27 Site and regional investigations can be planned based on field reconnais-28 sance data from previous investigations and reviews of available documents. 29 Possible sources of information may include universities, consulting firms, 30 and government agencies. A detailed list of possible sources of information 31 is given in Regulatory Guide 1.132. 32 33 D.2.3 Detailed Investiaations To Characterize Seismic Sources 34 35 The following methods are suggested but they are not all-inclusive 36 and investigations should not be limited to them. Some procedures will 37 not be applicable to every site, and situations will occur that require . D-4 l
l l 1 investigations that are not included in the following discussion. It is j D2 3 anticipated that new technologies will be available in the future that will be applicable to these investigations. l 4 5 D.2.3.1 Surface Investiaetions 6 Surface exploration needed to assess neotectonic conditions of the 7 geology of the area around the site is dependent on the site location and may 8 be carried out with the use of any appropriate combination of geological, 9 geophysical, seismological, and geotechnical engineering techniques. 10 11 0.2.3.1.1. Geological interpretations of aerial photographs and other 12 remote-sensing imagery, as appropriate for the particular site conditions, to 13 assist in identifying rock outcrops, faults and other tectonic features, frac-14 ture traces, geologic contacts, lineaments, soil conditions, and evidence of 15 landslides or soil liquefaction. 16 17 D.2.3.1.2. Mapping of topographic, geologic, geomorphic, and hydrologic 18 features at scales and contour intervals suitable for analysis, stratigraphy 19 (particularly Quaternary), surface tectonic structures such as fault zones, 20 and Quaternary geomorphic features. For offshore sites, coastal sites, or 21 sites located near lakes or rivers, this includes topography, geomorphology 22 (particularly mapping marine and fluvial terraces), bathymetry, geophysics 23 (such as seismic reflection), and hydrographic surveys to the extent needed 24 for evaluation. 25 26 0.2.3.1.3. Identification and evaluation of vertical crustal movements 27 by (1) geodetic land surveying to identify and measure short-term crustal 28 movements (Refs. 2D and 3D) and (2) geological analyses such as analysis of 29 regional dissection and degradation patterns, marine and lacustrine terraces 30 and shorelines, fluvial adjustments such as changes in stream longitudinal 31 profiles or terraces, and other long-term changes such as elevation changes 32 across lava flows (Ref. 4D). 33 34 0.2.3.1.4. Analysis of offset, displaced, or anomalous landforms such as 35 displaced stream channels or changes in stream profiles or the upstream migra-36 tion of knickpoints (Refs. 50-100), abrupt changes in fluvial deposits or D-5
l l 1 terraces, changes in paleochannels across a fault (Ref. 9D), or uplifted, 2 downdropped, or laterally displaced marine terraces (Ref.10D). 3 4 D.2.3.1.5. Analysis of Quaternary sedimentary deposits within or near l 5 tectonic zones such as fault zones and including: (1) fault-related or fault-6 controlled deposits, including sag ponds, graben fill deposits, and colluvial i 7 wedges formed by the erosion of a fault paleoscarp and (2) non-fault-related, 8 but offset deposits including alluvial fans, debris cones, fluvial terrace, 9 and lake shoreline deposits. 10 I 11 0.2.3.1.6. Identification and analysis of deformation features caused by 12 vibratory ground motions, including seismically induced liquefaction features 13 (sand boils, explosion craters, lateral spreads, settlement, soil flows), mud 14 volcanoes, landslides, rockfalls, deformed lake deposits or soil horizons, 15 shear zones, cracks, or fissures (Refs. 11D and 12D). 16 17 D.2.3.1.7. Estimation of the ages of fault displacements by analysis of 1 18 the morphology of topographic fault scarps associated with or produced by sur-19 face rupture. Fault scarp morphology is useful in estimating age of last dis-20 placement, approximate size of the earthquake, recurrence intervals, slip 21 rate, and the nature of the causative fault at depth (Refs. 13D-160). 22 23 0.2.3.2 Seismoloaical Investiaations l 24 l 25 0.2.3.2.1. Listing all historically reported earthquakes that can 26 reasonably be associated with seismic sources, any part of which is within a 27 radius of 320 km (200 miles) of the site, including date of occurrence and the 28 following measured or estimated data: highest intensity, magnitude, epi-29 center, depth, focal mechanism, stress drop, etc. Historical seismicity 30 includes both historically reported and instrumentally recorded data. For 31 pre-instrumentally recorded data, intensity should be converted to magnitude, 32 the procedure used to convert it to magnitude should be clearly documented, 33 and epicenters should be determined based on intensity contours. Methods to 34 convert intensity values to magnitudes in the central and eastern U.S. are 35 described in References 170-19D. D-6
I 1 D.2.3.2.2. Seismic monitoring in the site area that is established as l 2 soon as possible after site selection. 3 l 4 D.2.3.3 Subsurface Investiaations 5 Subsurface investigations in the site area or within the region to 6 identify and define seismogenic sources and capable tectonic sources may 7 include: 8 9 D.2.3.3 1 Geophysical investigations such as air or ground magnetic and 10 gravity surveys, seismic reflection and seismic refraction surveys, borehole 11 geophysics, and ground-penetrating radar. 12 13 0.2.3.3.2. Core borings to map subsurface geology and obtain samples for 14 testing such as age dating. 15 16 0.2.3.3.3. Excavating and logging trenches across geological features as 17 part of the neotectonic investigation and to obtain samples for age-dating 18 those features. 19 20 At some sites, deep soil, bodies of water, or other material may obscure 21 geologic evidence of past activity along a tectonic structure. In such cases, 22 the analysis of evidence elsewhere along the structure can be used to evaluate 23 its characteristics in the vicinity of the site (Refs. 10D and 200). 24 25 D2.4 Aae-Datina 26 27 An important part of the geologic investigations to identify and define 28 potential seismic sources is the age-dating of geologic materials. The 29 following techniques are useful in dating Quaternary deposits. 30 31 D2.4.1 Radiometric Datina Methods 32 33
- Carbon 14 for dating organic materials (upper limit ranges from 34 30,000 up to 100,000 years) (Ref. 210).
35
- Potassium argon for dating volcanic rocks ranging in age from about 36 50,000 to 10 million years (Ref. 21D).
D-7
l 1
- Uranium series using the relative properties of various decay 2 products of 23a0 or 235 U. Ages range from 10,000 to 350,000 (Ref.
235 238 3 21D). 0/ 0 can yield between 40,000 and 1,000,000 years (Ref. 4 22D). 5
- Fission track using minerals such as zircon and apatite, with 6 fissionable uranium in volcanic rocks. Although some interpretation 7 is required in counting tracks, the technique has no inherent age 8 range limitations if suitable materials are available (Ref. 210).
9
- Thermoluminescence (TZ) is best used for stratigraphic correlation 10 and determining relative ages rather than absolute ages. The l 11 maximum age is 10 million years (Ref. 210).
12
- Electron spin resonance (ESR) is used to date quartz that formed in 13 fault gouge during the fault event (Ref. 23D).
14 ! 15 D2.4.2 Other Ouantitative Nomerical Methods 16 17
- Paleomagnetic dating requires material containing magnetic-18 susceptible minerals with sufficient stratigraphic and time ranges 19 to provide several reversals. An independent time datum for 20 correlation with the polarity time scale is required (Ref. 21D). '
21
- Thicknesses of weathering rind development on the margins of clasts, 22 such as caused by obsidian hydration, can be used to estimate the 23 age of deposits (Ref. 240).
24
- Cation-ratio dating of desert varnish on rock surfaces by chemical l 25 analysis (Ref. 25D).
26
- Tephrochronology, which is the identification and correlation of 27 undated and dated volcanic ashes by geochemical and petrographic 28 analyses (Refs. 26D and 27D).
29
- Amino-acid racemization, which uses organi: material and is based on 30 time-dependent diagenetic conversion of one form of amino-acid 31 polymer structure to another (Refs. 280 and 290).
32
- Lichenometry is used to estimate ages from sizes of lichens growing 33 on gravel or boulders (such as glacial deposits) (Ref. 30D).
34
- Soil profile development is used to determine age based on measured 35 amounts of accumulated pedogenic materials (Ref. 31D).
O D-8
1
- Dendrochronology is used to determine the ages of trees that were affected by a tectonic event or othe* phenomena such as landsliding D2 3 or flooding (Refs. 32D-34D).
4 5 D2.4.3 Relative Aae-Datina Methods 6 7
- The relative degree of soil profile development of B and C horizons 8 can provide at least an order of magnitude estimate of the ages of 9 buried soils or relict surface soils on surficial deposits (Refs.
10 21D and 350). For B horizons, the diagnostic characteristics 11 include thickness, depth, amount, texture, type of clay, soil 12 structure and color, and amount of Fe oxides or Fe-Al-organic 13 accumulation (Ref. 210). For C horizons, the important diagnostic 14 characteristics are thickness, depth, stage of development, and 15 amount of pedogenic carbonate and other soluble salts (Refs. 36D and 16 37D). Other references for this subject include References 38D 17 through 420. 18
- The relative degree of weathering of surface and subsurface clasts D 1920 in sedimentary deposits such as glacial moraines is useful but 21 requires independent means of age calibration (Ref. 210).
22 23 In the SCR it may not be possible to demonstrate, in an absolute manner, 24 the age of last activity of a tectonic structure. In such cases the NRC staff ' 25 will accept association of such structures with geologic structural features 26 or tectonic processes that are geologically old (at least pre-Quaternary) as i 27 an age indicator in the absence of conflicting evidence. l 28 These investigative procedures should also be applied, where possible, to 29 characterize offshore structures (faults or fault zones, as well as folds, l 30 uplift, or subsidence related to faulting at depth) for coastal sites or those l 31 sites located adjacent to landlocked bodies of water. Investigations of off-32 shore structures will rely heavily on seismicity, geophysics, and bathymetry 33 rather than conventional geologic mapping methods that can be used effectively 34 onshore. However, it is often useful to investigate similar features onshore 35 to learn more about the significant offshore features. l 36 37 D-9
l l 1 D2.5 Distinction Between Tectonic and Nontectonic Deformation l 2 3 Nontectonic deformation, like tectonic deformation, can pose a substan-8 4 tial hazard to nuclear power plants, but there are likely to be differences in 5 the approaches used to resolve the issues raised by the two types of pheno- 1 6 mena. Therefore, non-tectonic deformation should be distinguished from tec-7 tonic deformation at a site. In past nuclear power plant licensing activi-8 ties, surface displacements caused by phenomena other than tectonic phenomena 9 have been confused with tectonically induced faulting. Such features include 10 faults on which the last displacement was induced by glaciation or deglacia-11 tion; collapse structures, such as found in karst terrain; and growth fault-12 ing, such as occurs in the Gulf Coastal Plain or in other deep soil regions 13 subject to extensive subsurface fluid withdrawal. 14 Glacially induced faults generally do not represent a deep-seated seismic 15 or fault displacement hazard because the conditions that created them are no 16 longer present. However, residual stresses from Pleistocene glaciation may 17 still be present in glaciated regions although they are of less concern than 18 active tectonically induced stresses. These features should be investigated 19 with respect to their relationship to current in situ stresses. 20 The nature of faults related to collapse features can usually be defined 21 through geotechnical investigations and either can be avoided or, if feasible, 22 adequate engineering fixes can be provided. 23 Large naturally occurring growth faults such as found in the coastal 24 plain of Texas and Louisiana can pose a surface displacement hazard, even 25 though offset most likely occurs at a much less rapid rate than that of tec-26 tonic faults. They are not regarded as having the capacity to generate damag-27 ing earthquakes, can often be identified and avoided in siting, and their 28 displacements can be monitored. Some growth faults and antithetic faults l 29 related to growth faults are not easily identified; therefore, investigations l 30 described above with respect to capable tectonic faults and fault zones should 31 be applied in regions where growth faults are known to be present. Local 32 human-induced growth faults can be monitored and controlled or avoided. 33 If questionable features cannot be demonstrated to be of non-tectonic l 34 origin they should be treated as tectonic deformation. 35 1 36 D-10
I REFERENCES 3 10. International Atomic Energy Agency, " Earthquakes and Associated Topics in 4 Rel tion to Nuclear Power Plant Siting," Safety Series No. 50-SG-S1, 5 Revision 1, 1991. 6 7 2D. R. Reilinger, M. Bevis, and G. Jurkowski, " Tilt from Releveling: An 8 Overview of the U.S. Data Base," Tectonoohysics, Vol. 107, p. 315-330, 9 1984. 10 11 3D. R. K. Mark et al., "An Assessment of the Accuracy of the Geodetic 12 Measurements that Led to the Recognition of the Southern California 13 Uplift," Journd si Geophysical Research, Volume 86, pp. 2783-2808,1981. 14 15 4D. T. K. Rockwell et al., " Chronology and Rates of Faulting of Ventura River 16 Terraces, California," Geoloaical Society of America Bulletin, Volume 95, 17 pp. 1466-1474, 1984. 18 19 5D. K. E. Sieh, " Lateral Offsets and Revised Dates of Prehistoric Earthquakes 20 at Pallett Creet, Southern California," Journal of Geoohysical Research, 21 Volume 89, No. 89, pp. 7641-7670, 1984. 22 23 6D. K. E. Sieh and R. H. Jahns, " Holocene Activity of the San Andreas Fault 24 at Wallace Creek, California," Geoloaical Society of America Bulletin, 25 Volume 95, pp. 883-896, 1984. 26 27 7D. K. E. Sieh, M. Stuiver, and D. Brillinger, "A More Precise Chronology of 28 Earthquakes Produced by the San Andreas Fault in Southern California," 29 Journal of Geophysical Research, Volume 94, pp. 603-623,1989. 30 31 80. R. J. Weldon, III, and K. E. Sieh, " Holocene Rate of Slip and Tentative 32 Recurrence Interval for Large Earthquakes on the San Andreas Fault, Cajon 33 Pass, Southern California," Geoloaical Society of America Bulletin, 34 Volume 96, pp. 793-812, 1985. , 35 36 90. F. H. Swan, III, D. P. Schwartz, and L. S. Cluff, " Recurrence of Moderate 37 to Large Magnitude Earthquakes Produced by Surface Faulting on the D-11
1 Wasatch Fault Zone," Bulletin of the Seismoloaical Society of America, 2 Volume 70, pp. 1431-1462, 1980. 3 4 100. Pacific Gas and Electric Company, " Final Report of the Diablo Canyon Long 5 Term Seismic Program; Diablo Canyon Power Plant," Docket Nos. 50-275 and 6 50-323, 1988.* 7 8 110. S. F. Obermeier et al., " Geologic Evidence for Recurrent Moderate to 9 Large Earthquakes Near Charleston, South Carolina," Science, Volume 227, 10 pp. 408-411, 1985. 11 12 120. D. Amick et al., "Paleoliquefaction Features Along the Atlantic 13 Seaboard," U.S. Nuclear Regulatory Commission, NUREG/CR-5613, October I 14 1990. 15 16 130. R. E. Wallace, " Profiles and Ages of Young Fault Scarps, North-Central 17 Nevada," Geoloaical Society of America Bulletin, Volume 88, pp.1267-8 1281, 1977. 20 14D. R. E. Wallace, " Discussion--Nomographs for Estimating Components of Fault 21 Displacement from Measured Height of Fault Scarp," Bulletin of the 22 Association of Enaineerina Geoloaists, Volume 17, pp. 39-45,1980. 23 24 150. R. E. Wallace, " Active Faults, Paleoseismology, and Earthquake Hazards: 25 Earthquake Prediction--An International Review," Maurice Ewing Series 4, 26 American Geoohysical Union, pp. 209-216, 1981. 27 28 16D. A. J. Crone and S. T. Harding, " Relationship of Late Quaternary Fault 29 Scarps to Subjacent Faults, Eastern Great Basin, Utah," Geoloav, Volume 30 12, pp. 292-295, 1964. 31 32 170. O. W. Nuttli, "The Relation of Sustained Maximum Ground Acceleration and 33 Velocity to Earthquake Intensity and Magnitude, State-of-the-Art for 34 *Available for inspection or copying for a fee at the NRC Public Document Room, 35 2120 L Street NW., Washington, DC. D-12
1 Assessing Earthquake Hazards in the Eastern United States," U.S. Army D2 Corps of Engineers Misc. Paper 5-73-1, Report 16, 1979. 3 4 180. R. L. Street and F. T. Turcotte, "A Study of Northeastern North America 5 Spectral Moments, Magnitudes and Intensities," Bulletin of the Seismo-6 loaical Society of America, Volume 67, pp. 599-614,1977. 7 8 19D. R. L. Street and A. Lacroix, "An Empirical Study of New England Seis-9 micity," Bulletin of the Seismoloaical Society of America, Volume 69, pp. 10 159-176, 1979. 11 12 200. H. Rood et al., " Safety Evaluation Report Related to the Operation of 13 Diablo Canyon Nuclear Power P1 ant, Units 1 and 2," USNRC, NUREG-0675, 14 Supplement No. 34, June 1991. 15 16 210. J. F. Callender, " Tectonics and Seismicity," Chapter 4 in " Techniques for 17 Determining Probabilities of Events and Processes Affecting the Perfor-mance of Geologic Repositories," NUREG/CR-3964 (SAND 86-0196), Volume 1, I D1819 Edited by R. L. Hunter and C. J. Mann, pp. 89-125, June 1989. 20 21 220. D. R. Muhs and B. J. Szabo, " Uranium-Series Age of the Eel Point Terrace, 22 San Clemente Island, California," Geoloav, Volume 10, pp. 23-26,1982. 23 24 23D. M. Ikeya, T. liiki, and K. Tanaka, " Dating of a Fault by Electron Spin 25 Resonance on Intrafault Materials," Science, Volume 215, pp.1392-1393, 26 1982. 27 28 240. S. M. Colman and K. L. Pierce, " Weathering Rinds on Andesitic and 29 Basaltic Stones as a Quaternary Age Indicator, Western United States," 30 Professional Paper 1210, U.S. Geoloaical Survey, 1981. 31 32 250. R. I. Dorn, " Cation-Ratio Dating: A New Rock Varnish Age-Determination 33 Technique," Ouaternary Research, Volume 20, pp. 49-73, 1983. 34 35 26D. P. D. Sheets and D. K. Grayson, eds., Volcanic Activity and Human 36 Ecoloov, Academic Press, New York,1979. 37 D-13
l 1 270. S. Self and R. J. S. Sparks, eds., "Tephra Studies," Proceedinas of the 2 NATO Advanced Studies Institute. Techra Studies as a Tool in Ouaternary 3 Essearch, D. Reidel Publ. Co., Dordrecht, Holland, 1981. 4 5 28D. J. L. Bada and P. M. Helfman, " Amino Acid Racemization Dating of Fossil 6 Bones," World Archeoloav,1975. 7 8 29D. J. L. Bada and R. Protsch, " Racemization Reaction of Aspartic Acid and 9 its Use in Dating Fossil Bones," Proceedinas of the National Academy of Science, Volume 70, pp. 1331-1334, 1973. 10 11 12 300. W. W. Locke, J. T. Andrews, and P. J. Webber, "A Manual for Licheno-13 metry," Technical Bulletin 26, British Geomorphological Research Group, 14 University of East Anglia, Norwich, 1979. 15 16 310. M. N. Machette, " Dating Quaternary Faults in the Southwestern United 17 States by Using Buried Calcic Paleosols," U.S. Geoloaical Survey Journal 8 of Research, Volume 6, pp. 369-381, 1978. 20 320. R. Page, " Dating Episodes of Faulting from Tree Rings: Effects of the 21 1958 Rupture of the Fairweather Fault on the Tree Growth," Geoloaical 22 Society of America Bulletin, Volume 81, pp. 3085-3094,1970. 23 24 33D. K. E. Sieh, " Prehistoric Earthquakes Produced by Slip on the San Andreas 25 Fault at Pallett Creek, California," Journal of Geoohysical Research, , 26 Volume 83, pp. 3907-3939, 1978. 27 28 34D. B. F. Atwater and D. K. Yamaguchi, " Sudden, Probably Coseismic Submer-29 gences of Holocene Trees and Grass in Coastal Washington State," Geoloav, 30 Volume 19, pp. 706-709, 1991. 31 32 350. M. N. Machette, " Soil Dating Techniques, Western Region (United States)," 33 Open-file Report 0FR-82-840, U.S. Geological Survey, p. 137-140, 1982. l 34 35 360. L. D. McFadden and J. C. Tinsley, " Soil Profile Development in Xeric 36 Climates: A Summary," in J. C. Tinsley, J. C. Matti, and L. D. McFadden D-14
1 eds., Guidebook. Field Trio No.12, Geological Society of America, 2 Cordillera Section, pp. 15-19, 1982. 3 4 370. J. W. Hardin, "A Quantitative Index of Soil Development from Field 5 Descriptions: Examples from a Chronosequence in Central California," 6 Geoderma, Volume 28, pp. 2-18, 1982. 7 8 380. J. C. Matti et al., " Holocene Faulting History as Recorded by Alluvial 9 Stratigraphy Within the Cucamonga Fault Zone; A Preliminary View," l 10 in J. C. Tinsley, J. C. Matti, and L. D. McFadden, eds., Guidebook. 11 Field Trio No.12, Geological Society of America, Cordillera Section, l 12 pp. 29-44, 1982. 13 14 390. P. A. Pearthree and S. S. Calvo, " Late Quaternary Faulting West of the 15 Santa Rita Mountains South of Tucson, Arizona," Masters Thesis, 16 University of Arizona, Tucson, AZ, 1982. 17 _ 18 400. P. A. Pearthree, C. M. Menges, and L. Mayer, " Distribution, Recurrence, 19 and Possible Tectonic Implications of Late Quaternary Faulting in 20 Arizona," Open-file Report 83-20, Arizona Bureau of Geology and Mineral 21 Technology, Tucson, 1983. 22 23 410. E. A. Keller et al., " Tectonic Georrorphology of the San Andreas Fault 24 Zone in the Southern Indio Hills, Coachella Valley, California," 25 Geoloaical Society of America Bulletin, Volume 93, pp. 45-56,1982. 26 27 420. O. A. Chadwick, S. Hecker, and J. Fonseca, "A Soils Chronosequence at 28 Terrace Creek: Studies of Late Quaternary Tectonism in Dixie Valley, 29 Nevada," Open-file Report 84-0090, U.S. Geological Survey, 1984. 30 31 D-15
1 BEGULATORY ANALYSIS 2 I 3 A separate regulatory analysis was not prepared for this regulatory 4 guide. The draft regulatory analysis, " Proposed Revision of 10 CFR Part 100 5 and 10 CFR Part 50," provides the regulatory basis for this guide and examines 6 the costs and benefits of the rule as implemented by the guide. A copy of the ; 7 draft regulatory analysis is available for inspection and copying for a fee at 8 the NRC Public Document Room, 2120 L Street NW. (Lower Level), Washington, DC, 9 as Enclosure 2 to Secy 92-215. 10 l l l Printed on recycled paper Federa! Recycling Program i RA-1
UNITED STATES FiRST CLASS Mall NUCLEAR REGULATORY COMMISSION POSTAGE AND FEES PAID WASHINGTON, D.C. 20555-0001 USNRC PEP.MIT NO. G-67 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE, $300 i
1 A3) 7 ~3 -l
*P D (L ;
o 1 STANDARD REVIEW PLAN 2.5.2 November 1992 i 2 VIBRATORY GROUND MOTION
Contact:
i 3 PROPOSED REVISION 3 A. J. Murphy l 4 (301)492-3860 ; 5 REVIEW RESPONSIBILITIES 6 Primary - Structural and Geosciences Branch (ESGB) 7 Secondary - None MI 8 AREAS OF REVIEW gkv 45 gt 9 The Structural and Geosciences Branch# creView covers the 10 seismological and geological investigatiolis%6arried out to 11 establ4eh evaluate the acceleration f5e *the" safe shutdown 12 earthquake ground motion (SSE) and-t4Qr$t-$ng-basic carthquake 13 -{OBB)- for the site. The cafc c an {.ht4cwn$len~5arthquake ic that 14 eaethquake-that 10 based-upon s evalda of the maximum 15 earthquake-petent4e4-eeneider4ng-thb--rc{ibbal and-leea4--geology-and 16 eelemology and cpecific chareetdiil::~cc of local cubcurface 17 material. It ic that carthb a Q 4at produccc t-he-ua*1eum 18 vibrateey-ground-met-len for 3;hicid-eafety-relat-ed-st-euetatree r - 19 systcmc, and-eempenents-are-designs 4--to-remain--funet4cnc l . The i 20 operating-baele-eaethquake iS@hiit carthquake-that, considering the 21 eeg-lenal-end-leca l gc61cgy,"lociamelogy, and cpecific charac-22 teeleticc of local cubcurface material, could reasonably be 33 ewpeet-ed to-af-f+ot-the-pkant$91-te-dueing-the-operat4-ng lif e of the 34 plent-1 it is that fa'etbuake-that-produccc the vibratory-ground 25 met 4en <cr whichhhe:k featurec of- -the nuclear poucr plent necessary for contidod4>perat4en-wi-thout unduc risk to the health 26 27 and cafety of t-hc public arc designed to remain fanetional. The 28 SSE represents the potential for earthquake ground motion at the 29 site andgi's(the vibratory ground motion for which certain 30 $ systems, and components are designed to remain 31 structures g% The SSE is based upon a detailed evaluation of the functiona,1. 33 earthquakeg p6tential, taking into account regional and local 33 geology, $ Quaternary tectonics, seismicity, and specific 34 characteristics of local subsurface material. It is defined as the 35 freMfield ground response spectra at the plant site and is 36 described by horizontal and vertical response spectra corresponding 37 to the expected ground motion at the free-field ground surface or 38 a hypothetical rock outcrop. 39 Guidance is being developed on seismological and geological 40 investigations and it is described in Draft Regulatory Guide DG-41 1015, " Identification and Characterization of Seismic Sources, 43 Deterministic Bource Earthquakes, and Ground Motion." These
) Public comment period I expiros March 24, 1993. 2.5.2-1
1 investigations describe the seismicity of the site region and the 2 correlation of earthquake activity with seismic sources. seismic 3 sources are identified and characterized, including the l 4 deterministic source earthquake (DSE) associated with each seismic l 5 source. All seismic sources that have any part within 320 km (200 6 miles) of the site must be identified. More distant sources that 7 are capable of earthquakes large enough to affect the site must 8 also be identified. Seismic sources can be capable tectonic 9 sources or seismogenic sources; a seismotectonic province is a , 10 type of seismogenic source. Both deterministic and probabilistic l 11 evaluations are used to assess the SSE. Acceptable deterministic 12 procedures are described in this BRP (Subsections 2.5.2.1 through 13 2.5.2.4). Probabilistic and deterministic methods are described in 14 Draft Regulatory Guide DG-1015. I 15 The principal regulation used by the staff in determining the scope ; 16 and adequacy of the submitted seismologic and geologic information ' 17 and attendant procedures and analyses is Appemlix 7., "Oc iam-le-and 18 Geolog4c Citing-C14tcria fee-Huelcar Pcuer P D nts n Appendix B, 19 " Criteria for the Seismic and Geologic Siting of Nuclear Power 20 Plants on or After [ Effective Date of this Regulation]" to 10 CFR 21 Part 100 (Ref. 1). Additional guidajlg..g information (regulations, 22 regulatory guides, and reports) is provided to the staff through 23 References 2 through 8 and 54. 24 Specific areas of review include seismicity (Subsection 2.5.2.1), 25 geologic and tectonic characteristics of the site and region 26 (Subsection 2.5.2.2), correlation o t' earthquake activity with 27 geologic structure or seismotectonic provinces (Subsection 28 2.5.2.3) , maximum earthquake potential and controlling earthquakes 29 (Subsection 2.5.2.4), seismic wave transmission characteristics of 30 the site (Subsection 2.5.2.5) , and safe shutdown earthquake ground 31 motion (Subsection 2.5.2.6), and operet4ng basic carthquake 32 -(-Subseet4en 2. 5. 2. 7 ) . 33 The geotechnical engineering aspects of the site and the models and 34 methods employed in the analysis of soil and foundation response to 35 the ground motion environment are reviewed under SRP Section 2.5.4. 36 The results of the geosciences review are used in SRP Sections 37 3.7.1 and 3.7.2. 38 II. ACCEPTANCE CRITERIA 39 The applicable regulations (Refs. 1, 2, and 3) and regulatory 40 guides (Refs. 4, 5, 6, and 54) and basic acceptance criteria 41 pertinent to the areas of this section of the Standard Review Plan 42 are: 43 1. 10 CFR Part 100, Append 4* ?., " Scicmle-and-Geeleg4c Citing 44 Griteria-for-Nuoleae-Power Plante r n-Appendix B, " Criteria for 45 the Seismic and Geologic Siting of Nuclear Power Plants on or 46 After [ Effective Date of this Regulation]." These criteria 2.5.2-2
I 1 describe the kinds of geologic and seismic information needed ) D23 4 to determine site suitability and identify geologic and seismic factors required to be taken into account in the siting and design of nuclear power plants (Ref. 1). l l 5 2. 10 CFR Part 50, Appendix A, " General Design Criteria for 6 Nuclear Power Plants"; General Design Criterion 2, " Design 7 Bases for Protection Against Natural Phenomena" (Ref. 2) . This 8 criterion requires that safety-related portions of the 9 structures, systems, and components important to safety she-14 10 be designed to withstand the effects of earthquakes, tsunamis, 11 and seiches without loss of capability to perform their safety 12 functions. 13 3. 10 CFR Part 100, " Reactor Site Criteria" (Ref. 3). This part 14 describes criteria that guide the evaluation of the 15 suitability of proposed sites for nuclear power and testing 16 reactors. 17 4. Regulatory Guide 1.132, " Site Investigations for Foundations 18 of Nuclear Power Plants." This guide describes programs of 19 site investigations related to geotechnical aspects that would 20 normally meet the needs for evaluating the safety of the site 1 21 from the standpoint of the performance of foundations under 22 anticipated loading conditions, including an earthquake. It 23 provides general guidance and recommendations for developing 24 site-specific investigation programs as well as specific 25 guidance for conducting subsurface investigations, including 26 the spacing and depth of borings as well as sampling intervals 27 (Ref. 4). 28 5. Regulatory Guide 4.7 (Proposed Revision 2, DG-4003), " General 29 Site Suitability Criteria for Nuclear Power Stations." This 30 guide discusses the major site characteristics related to 31 public health and safety wh-leh that the NRC staff considers in 32 determining the suitability of sites for nuclear power 33 stations (Ref. 5). 34 6. Regulatory Guide 1.60, " Design Response Spectra for Seismic 35 Design of Nuclear Power Plants." Thic gu-ide-givec- cnc method 36 acceptchic tc the NnC chaff f-or defining the recponce speet-re 37 eorresponding tc the expected =cximum-ground-eeccicret4en 38 (Ref. 5). Sec cice smoothed response spectra are generally 39 used for design purposes - for example, a standard spectral 40 shape that has been used in the past is presented in 41 Regulatory Guide 1.60 (Ref. 6). These smoothed spectra are 42 still acceptable when an appropriate paak acceleration is used 43 as the high-frequency asymptote and the smoothed spectra 44 compare favorably with site-specific response spectra derived 45 from the ground motion estimation procedures discussed in 46 Subsection 2.5.2.6. 2.5.2-3
1 7. Draft Regulatory Guide DG-1015 (Ref. 54), " Identification and 2 Characterization of Seismic Sources, Deterministic Source 3 Earthquakes, and Ground Motion," is being developed to 4 describe probabilistic and deterministic methodologies for 5 determining the controlling earthquakes for nuclear power 6 plant sites. 7 The primary required investigations are described in 10 CFR Part l 8 100, in Section IV(a) of Appendix A B(Ref. 1); The accepteMe ' 9 procedures for determining assessing the seismic design bases are 10 given in Sections V(a), (b), and (c). cnd Ocction VI(c) of the 11 appendix. Draft Regulatory Guide DG-1015 (Ref. 54) is being 12 developed to provide more detailed guidance on investigations. The seismic design bases are predicated on a reasonable, conservative i 13 i 14 determination of the SSE and the OBE. As dcfined stated in 15 Sections 4-1-1 IV and V of Appendix A B(Ref. 1) to 10 CFR Part 100, 16 the SSE and OBE cre is based on consideration of the regional and 17 local geology and seismology and on the characteristics of the 18 subsurface materials at the site. and The SSE are is described in I 19 terms of the vibratory grcund motion expected t-het they would i 20 produce at the site. No comprehensive definitive rules can be l 31 promulgated regarding the investigations needed to establish the i 22 seismic design bases; the requirements vary from site to site. ' 23 2.5.2.1 Seismicity. In meeting the requirement of Reference , 24 1, this subsection is accepted when the complete historical record 1 25 of earthquakes in the region is listed and when all available 26 parameters are given for each earthquake in the historical record. 27 The listing should include all earthquakes having Modified Mercalli l 28 Intensity (MMI) greater than u.; equel to IV or magnitude greater , 29 than or equal to 3.0 that have been reportc6 in all tec^ on-le i 30 previnccc for all seismic sources, any parts of which are within 31 320 km (200 miles) of the site. A regional-scale map should bc 32 presented showing all listed earthquake epicenters and should be 33 supplemented by a larger-scale map showing earthquake epicenters of 34 all known events within 80 km (50 miles) of the site. The 35 following information concerning each earthquake is required l 36 whenever it is available: epicenter coordinates, depth of focus, ! 37 origin time, highest intensity, magnitude, seismic moment, source 38 mechanism, source dimensions, distance from the site, and any 39 strong-motion recordings (sources from which the information was 40 obtained should be identified). All magnitude designations such as 41 m., M, t M,, M,, should be identified. In addition, any reported 42 earthquake-induced geologic failure, such as liquefaction, 43 landsliding, landspreading, and lurching .should be described 44 completely, including the level of strong motion that induced 45 failure and the physical properties of the materials. The 46 completeness of the earthquake history of the region is determined 47 by comparison to published sources of information (e.g., Refs. 9 48 through 13). When conflicting descriptions of individual 49 earthquakes are found in the published references, the staff should 2.5.2-4
l 1 1 determine which is appropriate for licensing decisions. l l 2 2.5.2.2 3 Recion. Geolooic and Tectonic Characteristics of Site and In meeting the requirements of References 1, 2, and 3, 4 5 this subsection is accepted when all geo-logic ctraeturcc within-the 6 reg-len-end-teeten-le-act-ivity seismic sources that are significant , in determining the earthquake potential of the region are l 7 identified, or when an adequate investigation has been carried out ) 8 to provide reasonable assurance that all significant teetonie 9 10 structures seismic sources have been identified. Information presented in Section 2.5.1 of tho applicant's safety analysis 1 11 report (SAR) and information from other sources (e.g., Refs. 9 and l 12 14 through 18) dealing with the current tectonic regime should be l 13 developed into a coherent, well-documented discussion to be used as I 14 the basis for characterizing the earthquake-generating potential of l 15 seismogenic sources and capable tectonic sources. the identified l 16 geologic- ct-eueturce Specit'ically, each teetenic province seismic 1 17 source, any part of which is within 320 km (200 miles) of the site, l 18 must be identified. The staff interprets seismotectonic provinces i 19 to be regions of uniform earthquake potent 4c1 (ccismoteeten-le 20 prov4nees-)- seismicity (same DSE and frequency of recurrence) 21 distinct from the seismicity of the surrounding area. The proposed 22 seismotectonic provinces may be based on seismicity studies, 23 differences in geologic history, differences in the current 24 tectonic regime, etc. The staff considers that the most important 25 factors for the determination of seismotectonic provinces include 26 both (1) development and characteristics of the current tectonic regime of the region that is most likely reflected -in-the D2728 neobeetenico (Postdi-lecenc or cbout 5 in the Quaternary 29 (approximately the last 2 million years and younger geologic 30 history) and (2) the pattern and level of historical seismicity. 31 Those characteristics of geologic structure, tectonic history, 32 present and past stress regimes, and seismicity that distinguish 33 the various seismotectonic provinces and the particular areas 34 within those provinces where historical earthquakes have occurred 35 should be described. Alternative regional tectonic models derived 36 from available literature sources, including previous SARs and NRC 37 staff Safety Evaluation Reports (SERs), should be discussed. The 38 model that best conforms to the observed data is accepted. In 39 addition, in those areas where there are capable fau-Its tectonic 40 sources, the results of the additional investigative requirements 41 described in 10 CPn Pcrt 100, Appendix ."., Ocction IV(c) (0) (Ref. 42 1) , BRP Section 2.5.1 must be presented. The discussion should be 43 augmented by a regional-scale map showing the teeten4e-provinc^c 44 seismic sources, earthquake epicenters, locations of geologic 45 structures and other features that characterize the seismogenic 46 sources (including seismotectonic provinces), and the locations of 47 any capable fau-It-s tectonic sources. 48 2.5.2.3 Correlation of Earthauake Activity with Ccolecic Ctructere 49 Seismocenic Sources (Includina Beismotectonic Provinces) and 50 Capable Tectonic Sources er Tectenic Provinees. In meeting the I 2.5.2-5
1 requirements of Reference 1, acceptance of this subsection is based 2 on the development of the relationship between the history of 3 earthquake activity and the geologic ctructurcc or ccienctcctonic 4 provinces seismic sources of a region. The applicant's 5 presentation is accepted when the earthquakes discussed in 6 Subsection 2.5.2.1 of the SAR are shown to be associated with 7 either geologie Otructurc or tectonic province capable tectonic 8 sources or seismogenic sources. Whenever an earthquake hypocenter 9 or concentration of earthquake hypocenters can be reasonably 10 correlated with geologic structures, the rationale for the 11 association should be developed considering the characteristics of 12 the geologic structure (including geologic and geophysical data, 13 seismicity, and the tectonic history) and the regional tectonic 14 model. The discussion should include identification of the methods 15 used to locate the earthquake hypocenters, an estimation of their 16 accuracy, and a detailed account that compares and contrasts the 17 geologic structure involved in the earthquake activity with other 18 areas within the teetenle-province seismotectonic provinco. Parti-19 cular attention should be given to determining the eapability 20 recency and level of activity of faults with which instrumentally 21 located earthquake hypocenters are associated. 22 The presentation should be augmented by regional maps, all of the 23 same scale, showing the tectonic provinccc seismic sources, the 24 earthquake epicenters, and the locations of geologic structures and 25 measurements used to define seismic sources prev 4nees. Acceptance 26 of the proposed t-eetonic provinces seismic sources is based on the i 27 staff's independent review of the geologic and seismic information. l l 28 2.5.2.4 Maximum Earthauake Potential and Contro11ina l 29 Earthquake (CE). In meeting the requirements of Reference 1, this l 30 subsection is accepted when the vibratory ground motion due-te from 31 the max 4num credible cart-hquake DSE associated with each geel-eg4e 32 steueture er the maximun-historic carthquake-essosieted-with-each 33 teetenic province seismic source has been assessed and when the 34 earthquake (s) that would produce the maximum most severe vibratory l 35 ground motion at the site has been determined. The maximum I 36 ered4-bic carthquake DSE is the largest earthquake that can 37 reasonably be expected to occur on a geelegic ctructure given 38 seismic source in the current tectonic regime. Considerable 39 judgment is involved in estimating the magnitude of the DSE. 40 Recommended procedures for estimating the DSE are described in 41 Draf t Regulatory Guide DG-1015 (Ref. 54) . Geologic or acicmoleg4ea+ 42 ev4denee-may ;; arrant a maximum carthquake larger than-the-maw-ieum 43 hictor-ic car-thquake . Earthquakes associated with each geclegio 44 etructure or tectonic-province seismic source must be identified. 45 Where If an earthquake is associated with a geologic structure, the 46 maximum credible-earthquake DSE that could occur on that structure 47 should be evaluated, taking into account significant factors, for 48 example, the type of the faulting, fault length, fault slip rate, ! 49 ruptmre length, rupture area, moment, and earthquake history (e.g. , 50 Refa. 19 through 22). 1 1 2.5.2-6
1 In order to determine the maximur credibic carthquake DSE that
} 23 could occur on those faults that are shown or assumed to be capable tectonic sources, the staff accepts conservative values based on 4 historic experience in the region and specific considerations of 5 the earthquake history and geologic history of movement on the 6 faults. Where the earthquakes are associated with a seismogenic 7 source tectonic province, the largest historic earthquake within 8 the source province should be identified. Isoseismal maps should 9 also be presented for the most significant earthquakes. The ground 10 motion at the site should be evaluated assuming appropriate seismic 11 energy transmission effects and assuming that the max-ieum 12 earthquake DSE associated with each geclogie-streeture er with cach 13 teetonic province seismic source occurs at the point of closest 14 approach of the structure or province to the site. (Further 15 description is provided in Subsection 2.5.2.6.)
16 The earthquake (s) that would produce the most severe vibratory 17 ground motion at the site should be defined. If different 18 potential earthquakes would produce the most severe ground motion 19 in different frequency bands, these earthquakes should be 20 specified. The description of the potential earthquake (s) is to 21 include the maximum intensity or magnitude and the distance from 22 the assumed location of the potential earthquake (s) to the site. 33 For the seismotectonic province surrounding the site, the DSE is 24 assumed to occur about 15 km from the site. The staff 25 independently evaluates the site ground motion produced by the 26 largcct carthquake DSE associated with each gcclogic ctructurc or I 27 tectonic province seismic source. 38 Controlling earthquakes are those earthquakes that produce the 29 largest ground motion at the nuclear power plant site. Procedures 30 for deriving controlling earthquakes from a probabilistic seismic 31 hazard analysis are discussed in Appendix C of Draft Regulatory 32 Guide DG-1015 (Ref. 54). Acceptance of the description of the 33 potential controlling earthquakes that would produce the largest 34 gr-eund motion at the cite is based on the staff's independent 35 analysis. 36 2.5.2.5 Seismic Wave Transmission Characteristics of the Site. 37 In meeting the requirements of Reference 1, this subsection is 38 accepted when the seismic wave transmission characteristics 39 (amplification or deamplification) of the materials overlying 40 bedrock at the site are described as a function of the significant 41 frequencies. The following material properties should be 42 determined for each stratum under the site: seismic compressional 3 43 and shear wave velocities, bulk densities, soil index properties j 44 and classification, shear modulus and damping variations with ' 45 strain level, and water table elevation and its variation. In each 46 case, methods used to determine the properties should be described 47 in Subsection 2.5.4 of the SAR and cross-referenced in this - 48 subsection. For the maximum carthquake CE(s) determined in 2.5.2-7 l _____._.___---.__j
I 1 Subsection 2.5.2.4 and Draft Regulatory Guide DG-1015 (Ref. 54), 2 the free-field ground motion (including significant frequencies) 3 must be determined, and an analysis should be performed to 4 determine the site effects on different seismic wave types in the 5 significant frequency bands. If appropriate, the analysis should l 6 consider the effects of site conditions and material property 7 variations upon wave propagation and frequency content. 8 The free-field ground motion (also referred to as control motion) i 9 should be defined to be on a ground surface and should be based on l 10 data obtained in the free field. Two cases are identified, 11 depending on the soil characteristics at the site and subject to 12 availability of appropriate recorded ground-motion data. When data 13 are available, for example, for relatively uniform sites of soil or 14 rock with smooth variation of properties with depth, the control 15 point (location at which the control motion is applied) should be 16 specified on the soil surface at the top of the site finished 17 grade. The free-field ground motion or control motion should be 18 consistent with the properties of the soil profile. For sites com- 1 19 posed of one or more thin soil layers overlying a competent 20 material, or in the case of insufficient recorded ground-motion l 21 data, the control point is specified on an outcrop or a 22 hypothetical outcrop at a location on the top of the competent 33 material. The control motion specified should be consistent with 24 the properties of the competent material. 25 Where vertically propagating shear waves may produce the maximum 26 ground motion, a one-dimensional equivalent-linear analysis (e.g. , 27 Ref. 23 or 24) or nonlinear analysis (e.g., Refs. 25, 26, and 27) 28 may be appropriate and is reviewed in conjunction with geotechnical 29 and structural engineering. Where horizontally propagating shear 30 waves, compressional waves, or surface waves may produce the 31 maximum ground motion, other methods of analysis (e.g., Refs. 28 32 and 29) may be more appropriate. However, since some of the 33 variables are not well defined and the techniques are still in the 34 developmental stage, no generally agreed-upon procedures can be 35 promulgated at this time. Hence, the staff must use discretion in 36 reviewing any nethod of analysis. To ensure appropriateness, site 37 response characteristics determined from analytical procedures 38 should be compared with historical and instrumental earthquake 39 data, when available. 40 2.5.2.6 Safe Shutdown Earthauake Ground Motion. In 41 meeting the requirements of Reference 1, this subsection is 42 accepted when the vibratory ground motion specified for the SSE is 43 described in terms of the free-field response spectrum and is at 44 least as conservative as that which would result at the site from 45 the maximum carthquake CEs determined in Subsection 2.5.2.4, 46 considering the site transmission effects determined in Subsection 47 2.5.2.5. If several different mawimum potentini car-thquakcc CEs 48 produce the largest ground motions in different frequency bands (as 49 noted in Subsection 2.5.2.4), the vibratory ground motion specified 2.5.2-8
1 2 for the SSE must be as conservative in each frequency band as that for each earthquake. 3 The staff reviews the free-field response spectra of engineering 4 significance (at appropriate damping values). 5 6 vary for different foundation conditions at theGround site. motion may When the 7 site effects are significant, this review is made in conjunction with the review of the design response spectra in Section 3.7.1 to 8 ensure consistency with the free-field motion. The staff normally 10 9 evaluates response spectra on a case-by-case basis. The staff 11 considers compliance with the following conditions acceptable in the evaluation of the SSE. In all these procedures, the proposed 12 13 free-field response spectra chall will be considered acceptable if 14 they equal or exceed the estimated 84th percentile ground-motion spectra from the =cximu= cr controlling carthquake CE described in 15 Subsection 2.5.2.4. 16 The following steps summarize the staff review of the SSE. 17 1. 18 Both horizontal and vertical component site-specific response spectra 19 should be developed statistically from response 20 spectra of recorded strong motion records that are selected to al have similar source, propagation path, and recording site 22 properties as the controlling earthquakes. It must be ensured 23 that the recorded motions represent free-field conditions and 24 are free of or corrected for any soil-structure interaction effects that may be present because of locations and/or ) 25 housing of recording instruments. Important source properties 26 include magnitude a 2, if possible, fault type, and tectonic 27 environment. Propagation path properties include distance, 28 depth, and attenuation. 29 Relevant site properties include 30 shear velocity profile and other factors that affect the 31 amplitude of waves at different frequencies. A sufficiently 32 large number of site-specific time-histories or response 33 spectra or both should be used to obtain an adequately 34 broadband spectrum to encompass the uncertainties in these parameters. 35 An 84th percentilo respense spectrum for the 36 records should be presented for each di uping value of interest and compared to the SSE free-f's .1 and design response 37 spectrum (e.g., Refs. 30, 31. se, and 33). The staff 39 considers direct estimates of spectral ordinates preferable to 39 40 scaling of spectra to peak accelerations. In the Eastern 41 United States, relatively little information is available on 42 magnitudes for the larger historic earthquakes; hence, it may 43 be appropriate to rely on intensity observations (descriptions 44 of earthquake effects) to estimate magnitudes of historic events (e.g. , Refs. 34 and 35) . If the data for site-specific 45 46 response spectra were not obtained under geologic conditions 47 similar to those at the site, corrections for site effects 48 should be included in the development of the site-specific spectra. 2.5.2-9
1 2. Where a large enough ensemble of strong-motion records is not 2 available, response spectra may be approximated by scaling 3 that ensemble of strong-motion data that represent the best 4 estimate of source, propagation path, and site properties 5 (e.g., Ref. 36). Sensitivity studies should show the effects 6 of scaling. 7 3. If strong-motion records are not available, site-specific peak 8 ground acceleration, velocity, and displacement (if necessary) 9 should be determined for appropriate magnitude, distance, and 10 foundation conditions. Then response spectra may be 11 determined by scaling the acceleration, velocity, and 12 displacement values by appropriate amplification factors 13 (e.g., Ref. 37). Where If only estimates of peak ground 14 acceleration are available, it is acceptable to select a peak 15 acceleration and use this peak acceleration as the high 16 frequency asymptote to standardized response spectra such as 17 described in Regulatory Guide 1.60 (Ref. 6) for both the 18 horizontal and vertical components of motion with the 19 appropriate amplification factors. For each controlling 20 earthquake, the peak ground motions should be determined using al current relations between acceleration, velocity, and, if 22 necessary, displacement, earthquake size (magnitude or i 23 intensity) , and source distance. Peak ground motion should be ! 24 determined from state-of-the-art relationships. Relationships 25 between magnitude and ground motion are found, for example, in 26 References 38, 39, 40, and 41 and relationships between ground 27 motion and intensity are found, for example, in References 41, ! 28 42, and 43. Duc to Because of the limited data for high l 29 intensities greater than Modified Mercalli Intensity (MMI) l 30 VIII, the available empirical relationships between intensity 31 and peak ground motion may not be suitable for determining the 32 appropriate reference acceleration for seismic design. l 33 4. Response spectra developed by theoretical-empirical modeling 34 of ground motion may be used to supplement site-specific 35 spectra if the input parameters and the appropriateness of the 36 model are thoroughly documented (e.g., Refs. 19, 44, 45, and 37 46, and 53). Modeling is particularly useful for sites near 38 capable faults tectonic sources or for deeper structures that 39 may experience ground motion that is different in terms of 40 frequency content and wave type from ground motion caused by 41 more distant earthquakes. 42 5. Probabilistic estimates of seismic hazard should be calculated l 43 -(-e rg . , "cfc. 41 and 47) and the underlying assumptions and l 44 associated uncertainties should be documented as discussed in l 45 Draft Regulatory Guide DG-1015 (Ref. 54). to-assist in t-he 46 staff'c overall determinictic approachr The probabilistic 47 studies should highlight which seismic sources are significant 48 to the site. Un44er-m-hasard-speet-ra-(epcctra- that-have a 49 uniform--probability cf exccedanee-over-the-f-requency-range-of 2.5.2-10
1 4ntercct) chcuing unecrtainty annual chould be calcu-leted-for 0.01, probabilitics Of-execcdance at the 0.001, and 0.0001 2 3 siter The annual probability of exceeding the SSE response spectra should also be estimated and comparedicen of-reculte 4 5 made with Other probabilictic studiesy with those of the 6 currently operating plants as required in Appendix B to 10 CFR 7 Part 100. Procedures for deriving the CEs from a PSHA and 8 estimating the annual probability of exceedance of(Appendices the SSE are B 9 contained in the Draft Regulatory Guide DG-1015 10 and C) (Ref. 54). 11 The time duration and number of cycles of strong ground motion are 12 required for analysis of site foundation liquef action potential The adequacy and of the time for design of many plant components. history for structural analysis is reviewed under SRP Section 13 3,7.1. The time history is reviewed in this SRP section to confirm 14~ 15 16 that it is compatible with the seismological and geological 17 conditions in the site vicinity and with the accepted SSE model. 18 At present, models for deterministically computing the time 19 be limited. It is therefore acceptable to use an ensemble of 20 21 ground-motion time histories from earthquakes with similar size, and spectral characteristics or site-source characteristics, Total 22 23 results of a statistical analysis of such an ensemble. l 24 duration of the motion is acceptable when it is as conservative 49, as 25 values determined using current studies such as References 48, 26 50, and 51. In-meet 4ng the 27 -2.5.2.7 Oncratinc-Sacic Earthcuakc. 28 requirementa of Reference 1, this-subsection ic acceptable-when-the dcccribed and44e-respense 29 v4bratcry ground-not-icn for the CSE 10 30 spectrum (at appropriate (c.g., damping /alucc) at-the cite apccified. Refc. ti, 47, and 52) cheu44-be 31 Probability calculations 32 used-tc cotimate-the-probab-ility of exceed 4eg-tec OBE during-theThe ma 33 operat-ing life of the plant. 34 cf the OBE chculd be at Icast-enc--half the max 4 mum-v4beatery-ground 35 motien of the SSE unlccc a lowcr OBB-ean It has bc justified been ctaff on to praet-ice theaceept basis 36 of-probability calculatienc.the-OBE if the return period ic cn the Order of hundr 37 38 (e.g., ncf. 31) . 39 III. REVIEW PROCEDURES an acceptance review is 40 Upon receiving the applicant's SAR, compliance with the investigative 41 conducted toof determine 10 CFR Part 100, Appendix A B (Ref. 1) . The 42 requirements 43 reviewer also identifies any site-specific problems, the resolution 44 of which could result in extended delays in completing the review. 45 After SAR acceptance and docketing, thocc arcac arc identified areas that need additional 46 where the reviewer identifies These 47 information 10 required-to determine the earthquake hazard. r 2.5.2-11 M
1 2 are transmitted to the applicant as draft requests for additional information. 3 4 A site visit may be conducted during which the reviewer inspects 5 theshown as geologic conditionsborings in outcrops, at the site and the region around the site 6 geophysical data, trenches, and 7 those is for geologic conditions an operating license.expose,d during construction if the review 8 9 questions with the applicant and Thehisreviewer also discusses the 10 staff to continue the review. clearly understood consultants soadditional what that it is information 11 set of requests Following the site visit, a revised for additional 12 information, including 13 additional questions that may hsve been developed during theany visit, site is formally transmitted to the applicant. 14 15 The reviewer prepares evaluates requests the applicant's response to the question s, 16 for additional clarifying information, and 17 formulates applicant. positions that may agree or disagree with those of the These are formally transmitted to the applicant. 18 19 The Safety Analysis Report and amendments responding to the 20 21 the information presented by the applicant is acceptable ng a 22 to the above. criteria described in Section II (Acceptance Criteria) 23 24 information Based on information supplied by the applicant and 25 or literature sources,obtained from site visits, er frca staff consultants, 26 evaluates the relevant ccic=cteetonic prcvinces seismogenic sour 27 and region the capable tectonic sources, evaluates the capability of faults in 28 and determines the earthquake potential for each 29 30 province-an,d cach-eapabic faultar tect-enic ctructure seismogenic source II or capableCriteria) (Acceptance tectonic source above. using procedures noted in Section 31 32 The reviewer evaluates the 33 produce SSE. at the site and definco compares that ground 00fc chutdcun carthquake and cperat-leg hacic carthquake - 34 IV. EVALUATION FINDINGS 35 36 If the evaluaticn by the ctcffy 37 geologic and seismologic aspects on completion of the review of the of the plant site, if the 38 evaluation byorthe requirements staff confirms guidance of that the applicant has met 39 40 through 6 and 54, the conclusion applicable portions of Referencesthe1 41 information provided and investigations in the SER states that the performed support the 42 applicant's conclusions subject nuclear power plant site. regarding the seismic integrity of the 43 In addition to the conclusion, 44 tectenic this section of the provincca SER includes (1) def-initions an evaluation seismogenic o 45 sources, (2) sources and capable tectonic 46 in the evaluations region, (3) of the capability of geologic structures 47 carthquakc (c)- DSEs and determinat-lens evaluation of the GGE free-field response spectra based on 2.5.2-12 i
1 evaluation of the potentici carthquakcc CEs, and (4) time-history 2 of strong ground motion, Staff and (5) determinatienc of the OBE frec-reservations about any significant
} field rcapcncc cpectrc.
3 in deficiency presented in the applicant's SAR are stated 4 5 sufficient detail to make clear the precise nature of the concern. 6 The above evaluations determinatienc cr redcterminations (CP), are made and 7 by the staff during be4Eh the construction permit 8 operating license (OL), combined license (COL) or early site permit 9 phases of review as appropriate. 10 OL applications are reviewed for any new information developed 11 subsequent to the CP safety evaluation report SER. The review 12 will also determine whether the CP recommendations have been 13 implemented. 14 A typical OL-stage summary finding for this section of the SER 15 follows: 16 In our review of the seismologic aspects of the plant site, we 17 have considered pertinent information gathered since our 18 initial seismologic review which that was made in conjunction 19 with the issuance of the Construction Permit. This new 20 information includes data gained from both site and near-site 21 investigations as well as from a review of recently published 22 literature. of our recent review of the seismologic m 23 As a result 24 information, we have determined that our earlier conclusion > 25 regarding the safety of the plant from a seismological l 26 standpoint remains valid. These conclusions can be summarized 27 as follows: 28 1. Seismologic information provided by the applicant and 29 required by Appendix A B to 10 CFR Part 100 provides an 30 adequate basis to establish that no capabic fault-e 31 seismic sources exist in the plant site area which that 32 would cause earthquakes to be centered there. 33 2. The response spectrum proposed for the safe shutdown earthquake is the appropriate free-field response 34 35 spectrum in conformance with Appendix A B to 10 CFR Part 36 100. 37 The new information reviewed for the proposed nuclear power 38 plant is discussed in Safety Evaluation Report Section 2.5.2. 39 The staff concludes that the site is acceptable from a 40 seismologic standpoint and meets the requirements of (1) 10 41 CFR Part 50, Appendix A (General Design Criterion 2), (2) 10 42 CFR Part 100, and (3) 10 CFR Part 100, Appendix A B. This 43 conclusion is based on the following: ( 2.5.2-13 y/ 1
1 1. The applicant has met the requirements of: . 2 a. 10 CFR Part 50, Appendix 3 A, General Design ' 4 Criterion 2 with respect to protection against natural phenomena such as faulting. 5 b. 10 CFR Part 100, Reactor Site Criteria, 6 respect to the with 7 seismic identification of geologic and 8 information used in determining the suitability of the site. 9 c. 10 10 CFR Part 100, Appendix A (Scic=ic cnd Occiegic 11 Siting B Oritcric for "uclecr Pcwcr Planta)- Appendix 12 (Criteria for the Seismic and Geologic Siting of 13 Nuclear Power Plants this Regulation] on or After (Effective Date of (Ref. 14 1)) with respect to 15 obtaining the geologic and seismic information 16 necessary to determine (1) site suitability and (2) 17 the appropriate design of the plant. Guidance for 18 complying with this regulation is contained in 19 Regulatory Guide 1.132, " Site Investigations for 20 Foundations of Nuclear Power Plants" (Ref. 4); 21 Draft Regulatory Guide DG-1015, " Identification and 22 Characterization of Seismic Sources, Deterministic Seismic Sources, and Ground Motion" 33 Regulatory Guide 4.7, (Ref. 54); 24 " General Criteria for Nuclear Power Stations" Site Suitability 25 (Proposed 26 Revision 2) (Ref. 5); and Regulatory Guide 1.60, 27 " Design Response Spectra for Feismic Design of Nuclear Power Plants" (Ref. 6). 28 V. IMPLEMENTATION 29 30 The following is intended to provide guidance to applicants and 31 licensees regarding the NRC staff's plans for using this SRP section. 32 33 Except in those cases in which the applicant or licensee proposes 34 an acceptable alternative method for complying with specific 35 portions of the Commission's regulations, the methods described 36 herein with will be used Commission by the staff in its evaluation of conformance regulations. 37 38 Implementation schedules for conformance to parts of the method 39 discussed herein are contained in the referenced regulatory guides and NUREGs (Refs. 4 through 8 and 54). 40 41 The provisions permits (CP), of this SRP section apply to reviews of construction operating licenses (OL), early site permits, 42 43 peell=incry design apprcycl (PDA), final design approval (TOA),- and 44 combined license (CP/OL) applications docketed pursuant to the proposed Appendix B to 10 CFR Part 100. cfter the-date of iccucnce 2.5.2-14
1 ef--thic SRP ccctient I 2 VI. REFERENCES 3 1. 10 CFR Part 100, Appendix ?., "Scicmic and Occiogic Siting 4 Criteria for "uclear Pcuer Plantc." Proposed Appendix B, 5 " Criteria for the Seismic and Geologic Siting of Nuclear Power 6 Plants on or After [ Effective Date of this Regulation]." 7 2. 10 CFR Part 50, Appendix A, General Design Criterion 2, 8 " Design Bases for Protection Against Natural Phenomena." 9 3. 10 CFR Part 100, " Reactor Site Criteria." 10 4. USNRC, " Site Investigations for Foundations of Nuclear Power 11 Plants," Regulatory Guide 1.132. 12 5. USNRC, " General Site Suitability Criteria for Nuclear Power Stations," Regulatory Guide 4.7 (Proposed Revision 2, DG-- 13 14 4003). 15 6. USNRC, " Design Response Spectra for Seismic Design of Nuclear 16 Power Plants," Regulatory Guide 1.60. 17 7. US NRC, " Standard Format and Content of Safety Analysis 18 Reports for Nuclear Power Plants (LWR Edition) ," Regulatory 19 Guide 1.70. 20 8. USNRC, " Report of Siting Policy Task Force," NUREG-0625, 21 August 1979. 22 9. N. L. Barstow et al., "An Approach to Seismic Zonation for , 23 Siting Nuclear Electric Power Generating Facilities in the d 24 Eastern United States," prepared by Roundout Associates, Inc. , 25 for the USNRC, NUREG/CR-1577, May 1981. 26 10. C. W. Stover et al., " Seismicity Maps of the States of the 27 U.S.," Geological Survey Miscellaneous Field Studies Maps, 28 1979-1981. 29 11. " Earthquake History of the United States," Publication 41-1, 30 National Oceanic and Atmospheric Administration, U.S. 31 Department of Commerce, 1982. R. Toppozada, C. R. Real, S. P. Bezore, and D. L. Parke, 32 12. T. 33 " Compilation of Pre-1900 California Earthquake History, Annual 34 Technical Report-Fiscal Year 1978-79, Open File Report 79-6 35 SAC (Abridged Version)," California Division of Mines and 36 Geology, 1979. 37 13. P. W. Basham, D. H. Weichert, and M. J. Berry, " Regional
, 38 Assessment of Seismic Risk in Eastern Canada," Bulletin of the l ,C m) 2.5.2-15
1 Seismoloalcal Society of America, Vol. 65, pp. 1567-1602, 2 1979. 3 14. P. B. 4 King, "The Tectonics of North America - A Discussion to Accompany the Tectonic Map of North America, 5 Scale 6 1:5,000,000," Professional Paper 628, U.S. Geological Survey, 1969. 7 15. 8 A. J. Eardley, " Tectonic Divisions of North America," Bulletin 9 of the American Association of Petroleum Geolocists, Vol. 35, 1951. 10 16. J. B. Hadley and J. F. 11 Devine, "Seismotectonic Map of the 12 Eastern United Survey, 1974. States," Publication MF-620, U.S. Geological 13 17. M. L. Sbar and L. R. Sykes, " Contemporary Compressive Stress 14 15 and Seismicity in Eastern North America: An Example of Intra-16 Plate Tectonics," Bulletin of the Geoloaical Society of America, Vol. 84, 1973. 17 18. R. B. Smith and 18 M. L. Sbar, " Contemporary Tectonics and 19 Seismicity of the Western United States with Emphasis on the Intermountain Seismic Belt," Bulletin of the Geoloaical 20 Society of America, Vol. 85, 1974. 21 19. USNRC 22 Relat " Safety Evaluation Report (Geology and Seismology) 23 Station, to the Operation Units 2 and 3," of San Onofre Nuclear Generating NUREG-0712, February 1981. 24 20. 25 D. B. Slemmons, " Determination of Design Earthquake Magnitudes 26 for Microzonation," Proceedinas of the Third International Earthauake Microzonation Conference, 1982. 27 21. 28 M. G. Bonilla, R. K. Mark, and J. J. Lienkaemper, " Statistical 29 Relations Among Earthquake Magnitude, Surface Rupture, Length 30 and Surface Fault Displacement," Bulletin of the Seismoloaical Lociety of America, Vol. 74, pp. 2379-2411, 1984. 31 22. T. C. Hanks and H. Kanamori, 32 "A Moment Magnitude Scale," Journal of Geophysical Research, Vol. 84, pp. 2348-2350,1979. 33 23. P. B. Schnabel, J. Lysmer, and H. B. 34 Seed, " SHAKE-A Computer 35 Program for Earthquake Response Analysis of Horizontally 36 Layered Sites," Report No. EERC 72-12, Earthquake Engineering Research Center, University of California, Berkeley, 1972. 37 24. E. 38 Faccioli and J. Ramirez, " Earthquake Response of Nonlinear 39 Hysteretic Soil Systems," International Journal of Earthauake 40 Enaineerina and Structural Dynamics, Vol. 4, pp. 261-276, 1976. 2.5.2-16
1 25. 2 I. V. Constantopoulos, " Amplification Studies for a Nonlinear 3 Hysteretic Soil Model," Report No. R73-46, Department of Civil Engineering, Massachusetts Institute of Technology, 1973. 4 26. V. L. Streeter, E. B. Wylie, and F. E. Richart, " Soil Motion 5 6 Computation American by Characteristics Methods," Proceedinas of the Society 7 of Civil Enaineers, Journal of the 8 Geotechnical 1974. Encineerina Division, Vol. 100, pp. 247-263, 9 27. W. B. Joyner and A. T. 10 F. Chen, " Calculations of Nonlinear 11 Ground Response in Earthquakes," Bulletin of the Seismoloaical Society of America, Vol. 65, pp. 1315-1336, 1975. 12 28. T. Udaka, J. Lysmer, and H. B. l 13 Seed, " Dynamic Response of Horizontally Layered Systems Subjected to Traveling Seismic i 14 Waves," Proceedinas of the Second U.S. National Conference on 15 Earthauake Enaineering, 1979. 16 29. L. A. 17 Drake, " Love and Raleigh Waves in an Irregular Soil 18 Layer," Bulletin of 70, pp. 571-582, the Seismoloaical Society of America, Vol. 1980. 19 30. USNRC, " Development of Site-Specific 20 Response Spectra," NUREG/CR-4861, March 1987. 21 31. USNRC, " Safety Evaluation Report Related to Operation of the D22 Sequoyah Nuclear Plant, Units 1 and 2," NUREG-0011, 1979. 23 32. 24 USNRC,Plant, Midland " Safety Evaluation Units 1 and 2,"Report Related to the Operation of NUREG-0793, May 1982. 25 33. 26 USNRC, " Safety Evaluation Report Related to the Operation of 27 Enrico Fermi Atomic Power Plant, Unit No. 2," NUREG-0847, July 1981. 28 34. R. L. Street and F. T. Turcotte, 29 "A Study of Northeastern 30 North American Spectral Moments, Magnitudes, and Intensities," 31 Bulletin of1977. 599-614, the Seismolocical Society of America, Vol. 67, pp. 32 35. O. W. Nuttli, G. A. Bollinger, and D. 33 W. Griffiths, "On the 34 Relation Between Modified Mercalli Intensity and Body-Wave 35 Magnitude," Bulletin of1979. Vol. 69, pp. 893-909, the Seismoloalcal Society of America, 36 36. T. H. Heaton, F. Tajima, and A. W. 37 Mori, " Estimating Ground 3B Motions Using Recorded Vol. 8, pp. 25-83, 1986. Accelerograms," Surveys in Geoohysics, 39 37. 40 USNRC, " Development of Criteria for Seismic Review of Selected Nuclear Power Plants," NUREG/CR-0098, June 1978. 2.5.2-17
I i l 1 38. W. B. Joyner and O. M. Boore, " Peak Horizontal Acceleration 2 and Velocity from Stror j Motion Records Including Records from 3 the 1979 Imperial Valley, Calitornia Earthquake," Bulletin of J the Seismoloaical Society of America, Vol. 71, 2011-2038, 4 5 1981. 6 39. K. W. Campbell, "Near-Source Attenuation of PeakSocietyHorizontal of 7 Acceleration," Rglietin of the Seismoloaical 8 America, Vol. 71, pp. 2039-2070, 1981. 9 40. O. W. Nuttli and R. B. Herrmann, " Consequences of Earthquakes 10 in the Mississippi Valley," Preprint 81-519, American Society 11 of Civil Engineers Meeting, 1981. 12 41. D. L. Bernreuter et al., " Seismic Hazard Characterization of i 13 69 Nuclear Plant Sites East of the Rocky Mountains," NUREG/CR- J 14 5250, January 1989. 15 42. M. D. Trifunac and A. G. Brady, "On the Correlation of Seismic 16 Intensity Scales with Peaks of Recorded Strong Ground Motion," 17 Bulletin of the Seismoloaical Society of America, Vol. 65, 18 1975. 19 43. J. R. Murphy and L. J. O'Brien, " Analysis of a Worldwide 20 Strong Motion Data Sample To Develop an Improved Correlation 21 Between Peak Acceleration, Seismic Intensity and Other 22 Physical Parameters," prepared by Computer Sciences 23 Corporation for the USNRC, NUREG-0402, January 1978. 24 44. USNRC, " Safety Evaluation Report Related to Operation of 25 Virgil C. Summer Nuclear Station, Unit No. 1," NUREG-0717, 26 1981. 27 45. USNRC, " State-of-the-Art Study Concerning Near-Field 28 Earthquake Ground Motion," NUREG/CR-1340, August 1980. 29 46. H. J. Swanger et al. , " State-of-the-Art Study Concerning Near-30 Field Earthquake Ground Motion," NUREG/CR-1978, March 1981. 31 47. " Seismic Hazard Methodology for the Central and Eastern United I 32 States," Electric Power Research Institute, Report NP-4726, ; 33 1986. 34 48. R. Dobry, I. M. Idriss, and E. Ng, " Duration Characteristics 1 35 of Horizontal Components of Strong-Motion Earthauake Records," j 36 Mqt;.in of the seismoloaical Society America, Vol. 68, pp. 37 1487-1520, 1978. I 38 49. B. A. Bolt, " Duration of Strong Ground Motion," Proceedinas of 39 the Fifth World Conference on Earthauake Enaineerina, 1973. 40 50. W. W. Hays, " Procedures for Estimating Earthquake Ground 2.5.2-18
1 Motions," Professional Paper 1114, U.S. Geological Survey,
} 2 1980.
3 51. H. Bolton Seed et al., " Representation of Irregular Stress 4 Time Histories by Equivalent Uniform Stress Series in 5 Liquefaction Analysis," National Science Foundation, Report 6 EERC 75-29, October 1975. 7 52. S. T. Algermissen et al., "Probabilistic Estimate of Maximum 8 Acceleration and Velocity in Rock in the Contiguous United 9 States," U. S. Geological Survey Open-File Report 82-1033, 10 1982. 11 53. USNRC, " Safety Evaluation Report Related to the Cperation of 12 Diablo Canyon Nuclear Power Plant, Units 1 and 2," NUREG-0675, 13 Supplement No. 34, June 1991. 14 54. USNRC, " Identification and Characterisation of Seismic 15 Sources, Deterministic Source Earthquakes, and Ground Notion," 16 Draft Regulatory Guide DG-1015, I Printed on recycled paper Federal Recycling Program C 2.5.2-19 g . . .. .. _ _ __m
4 i l UNITED STATES FinsT class MAIL s NUCLEAR REGUI.ATORY COMMISSION POSTAGE AND FEES PAID ' WASHINGTON, D.C. 20555-0001 USNRC
, PERMIT NO. G-67 i
-t ! OFFICIAL BUSINESS j PENALTY FOR PRIVATE USE,4300 l l a I b t t a E 4 f , i ! I t 1 .i 1 [ } } l 4 > [ l i l k l h _ . _ . . . . _ . _ . . _ _ . _ _ _ _ . _ _ _ _ ~ _ . - . _ , , _ . _. , , . . _ _
271 Federal Register / Val. 58, No. 2 / Tuesday, January 5,1993 / Proposed Rules l'P(L ' Commission, Washington,DC 20s55, . of the final regulation on September 21, Attention: Docketing and Serv,ce 1992. on2s et washlagkm, DC.an tw= 16, DATES: Comments must be received on
' Branch; .
1992 .
- Deliver comments to 11555 Rockville, or before February 1,1993, t
H. Russell Cross', Pike, Rockvllle, Maryland, between 7:45 AD0ntests: Comments should refer to Adminisemfor, Food Sofsty end inspeesion Docket No. R-4791,and reey be mailed
's.m. and 4:15 p.es., Federal workdays.
Servdoe Copies of the segul tory analysis, the to Mr. William W, Wiles. Secretary, ' IFR Doc. 93-67 Fi1Ed 1M; M45 *eel ' Board of Governors of the Federal envimenfasstal essessment and finding ' suses coes sew ouwe Scentimped, and comuments Reserve System 20th Street and _ ofno Constitution Avenue,NW., Washington, recel may be exanuned at the NRC Public D-== asst Room et 2120 L 9treet DC 20551. Comments also may be ' NUCLEAR REGULATORT NW. (Lower Level), Washington,DC. delivered to room B-2222 of the Eccles COMM18000N Building between 8:45 a.m. and 5:15
~^~ - -
POR pufmeser0setAnose 00HmcT: 10 CFR Parte 90, et and 100 Dr. Andsew J. y, Olhos of Nucient p.m. weekdays, or to the guard station
, U.S. Nuclear in the Eccles Building courtyard on 20th not$$eo Aces Regulatory Stseet, NW (WL.. Constitution Regulatory Cosiraission. Washington, Avenue and C Street) any time.
Reactor Site Crherte;inclusAn0 ^ DC20555, telephone (302) 492-3860, Comrnents may be inspected in Room Setemic and Earthquake 14Ionteengineering and - concerning espects and the Mr. seismic and Isonard earthquake B-1122 between 9 a.m, and 5 p.m. CrMerle for Nucteer Posser P weekdays, except as provided in 12 CFR P,y M Deniet of Petition Prom Free Soffer, Offim of Nuclear Regulatory 261.s of the Board's rules regardfag the . Environment,Inc et al. Research, U.S. Nuclear Regulatory . Commission, WasMagton, E ES, adeW hh. AGENCY: Nuclear Regulator'y '
' telephone (301) 492-3916, concerning FOR FUfmIBt 51F0fEAATION 000rfACT:
Commission. u or e Desed ! sad, this 29th day, c en and Community Affairs, at (202) 736- ; SutshARY:Da Odd-r 20.1092 (57 FR For the Nuclee Hagulatory C:mmIssion. 5500; for the hearingimpaired only 47802), the N'": published for public gg* a' contact Dorothea Thompaan, ; comanent a roposed rule to update the .. in decisions ing S'C"*F 'I Telecommunications Device for the criteria u IFR Doc. 93-48 Md 1-443; 8:45 aml Deef, at (202) 452-3544, Board of power reactor siting,inclu geologic, muse coes m*M Covernors of the Federal Reservo seismic, and eartho ake engineering System, Washington, DC 20551. considerations for bture nuclear power ' plants.The commentperiod for this - suPfMistmRY BdFORIAADON* proposed rule was to have expir9.1 on FEDERAL RESERVE' SYSTEM i
. (1) Background February 17,1993. The availability of The Truth in Savings Act (act) the five draft regulatory guides and the 12 CFR Part 230 (contained in the Federal Deposit standard review plan section that were developed to provide guidance on l; " DO; Dochet No. R-4791] InsuranceCorporationImy. Jnt Act meedng the proposed regulations was - _, of 1991) was enacted in December 1991.
i published on Novernber 25,1992 (57 FR rut ngs; n- s _ @M ne Board published proposed rules to 55601). Because the proposed rule implement the act on April 10,1992 (57 would move the detailed guidance from AGENcV: Board of Goverm *s of the FR 12735), and published a final the regulation and place it into a Federal Reserve Syrtem. regulation, Regulation DD, on ' September 21,1992 (57 FR 43337). reguletory guide, a critical evaluation of Em Proposed r' 'e. (correction notice at 57 FR 46480, the proposed rule could not be October 9,1992). performed until the draft regulatory soundARY: ne Board la publishing for The Housing and Community I guides and standard review plan secdon comment proposed amendments to were available. The NRC has stated that Regulation DD (Truth in Savings) to Development Act (HCDA) was enacted i in October 1992 (Pub. L.102-550,106 ' comments on the drsit regulatory guides implement recent changes made to the , and standard review plan section would Truth in Savings Act by the Housing Stat. 3672). The law contains three be most helpful if received by March 24, and Community Development Act of provisions that amend the Truth in 1993. In view of the importance of the 1992. The law extends the mandatory Savings Act.The provisions extend the effective date for compliance with the i proposed rule and the differences in the date for compliance with the act by three months, reduce the comment period, the NRC has decided requirements of the Truth in Savings , to extend the comment period on the - Act by three months, so that institutions requirements that apply to some advertisements on the psemises of a proposed rule for en additional thirty must comply by June 21,1993, rather deposito ~f insutution, and modify the ' etx daya. ne extended comment period than March 21,1993.ne law also ' now expires March 24,1993, modifies the advertising rules relating to provisiw that requires a notice to be si8ns in an institution's lobby, and given (misting account holders DATES:The comment period has been alerting < hem to the availabillty of extended and now expires March 24 makes a technical change to the 1993. Comments received after this date provision dealing with notices required account disclosums. To implement the changes, the Board will be considered if it is practical to do to be given to existing account holders. is proposing regulations for comment, so, but the Commission is able to essure in addition, the Board is proposing to and expects to adopt final amendments make a minor change to the regulation consideration only for comments before March 21,1993-the compliance received on or before this date. 'and clarify and provide addidonal poonesses: Mail written comments to: guidance on a few issues that have been date currently set forth in Regulation raised by institutions since publication DD. In light Ithe minor nature of the Secretary, U.S. Nuclear Regulatory i -- __ _
_ ._ ._._ _ _ . _ _. _ _ _ _ _ .._ _._ __ _ _.___ ___ _ ___._ _ _ _ __ l ! Federel Regieter / Wal. na, No. 57 / Fridiy, Masch 28, 1993 / Pseposed Roles 16377 MNdI l P)R s ahould canaider '- '-N wohicles Ier bened on bind that hpeepened rule DEPARTMENFOFTRANSPORFATION althu eliminating or further discnaaias presents dilEcukiss.se seqistsing ;
! mdividual oneses tha6 very widely from thoughtfui end emeful snelysis if the Federal Avletion Adminleiseafon 1: theeverage- commeon e e o t. be d esamisme vdue i to the Comentenien. he , _?", . 14 CFR Port 30
- 5. AgencySteff i
p " : of such conseenes inweb (a) Agencies bt rely on peer revim" [Dochet pee. SNeaM4-Aoy
- should ancaiangp thans staff menshers to care &d enseideration eithei"PI 'F P'e demogreyddc j play a signincana role la ensuring that Airworthiness Dissedvens Prestes rev>ewess ass welkinf===ad about, and g ,
Y Flight, ins.,Puleette tem beedet strictly observe, applir=hla rules er g8PN g* le g 1216-i guidelines on We end conflict of . Commission's Safety Geln, em g,,,,2406-t; es lueen,ned gg,,g,,,,; g,,,, ,,g g,in. Westeue 4 interest. accident requirements, and to CFR part gee ,g,,,,ynth W W l l (b) Agencies that adminiater enhiple 52, so well as propration of supporting Costificate(STC)SA4000 NAB l , progran.s for swesding discseasonary- analyses. j grants by peer revime should <=amider TheC-W herefore t finda that AGEsecV: Federal Aviatloa Administration,1Xyr. j rotating staff i - ' t='y esseng the it is reasonable to smiend the public programs. Especially in progsmens in cornn-8 period to June 1,1993,in Ac1tola: Notice of proposed rulsamking
! which peer senswers do met meet to order le allow alliaterested pensons (NPRM). ! ; rasch callective '- ( 7 agencies adequate time kw such caus&deratina. the l i should rotate the staff responsible for
SUMMARY
- Ws document 7. , '
mddag irdtiskleading DATES:The comment period has been adoption cia new air ./ " recoenmendeness. extended and now expime June 1,1993. disective(AD)that is applicehle le l; certala Precise F113 ba, lac paalaalha Comments received after this date will l DI AuditsforPbtentialBias be considered if it is practical to de so, units. This propaeal would requise Agencies that rely en peer review but the Commission is able to assure removal of certain puhelism unha,er j replacement d thoseunits with
- should experiment with sendom endits consideration only for comments l of the review process kirbias and racefved on or before th date. improved units,This propenalla
! confuct d interest. Prompted by reports that pulsalite unita ADDpenaw Mail writtee mem-te to: have overheated and Anled due to the i Dated: Masch 22,1993. Secretaay, U.S. Nuclear Regunstory I l inmaallanton of underrated treanisessa Idrmy S. tabbers, Comenission, Wasinngton, DC 20555, and the location d these teenah*=== in I -l nesearch Dhesesr. Attention: Docketing and Sernce relation to the hese eink fhas.The . i IFR Doc. 93-4424 Filed 3-25-03; 8.45 aral Branch. Denver comments to 11555 a<:tions speci&md by the ,,4 - - 1 AD
- sauno coca su+eo.w Rochville Pike, Rochri!!e, Maryland, are intended to prevent the presence of j between E45 a.m. and 4
- 15 p.m., smoke in the cockpit,which could s Federal workdays. prompt the pilot tolaitiate an
- NUCl. EAR REGut.ATORY emergency lamung.
Copics of the regulatory analysin, the COMMISSION enviromnental assessment and finding DATES: Comments must be received by 10 CFR Pasta 50,52, and 100 f no signincant impact,and comments May 21,1993. received may be examined at the NRC ADDRESSES: Submit comments in RIN 3150-AC93 Public Document Room at 2120 L Street triplicate to the Federal Aviation NW. (Lower Levolj, Washington, DC. Administration (TA A}, Transport Rasctor Site Criteria including Saismic Airplane Directorate. ANM-103, and Earthqueke Enghteering Criteria rOR FURTHER INFOWATION CON AC7r Attention: Rules Docket No. 93-NM- l for Nuclear Fomer Plants and Dr. Andrew J. Mm-by, Office of Nuclear 14-AD,1601 Lind Avenue SW., ) Proposed Denial of Petition From Free Regulatory Research, U.S. Nuclear Renton. Washington 98055-4058. Environment, Inc. et al Regulatory Commission, Washiagton, Commeuts may be laspected at this DC 20555, telephone (381) 432-3860, locatian between 9 a.m. and 3 p.m., A". ENCY:Noclaar Regulatory concerning the asmic and earthquake Monday through Friday, except Federe! Com nission. enginming aspecmad Mr. Michael T. holidays. AcnoN: Proposed rule: Extension of The service informatlou referenced in
'- " t
- d' Jamgochlan, Office of Nuclear !
Regulatory Researdt, U.S. Nuclear the proposed rule may be obtained from i
SUMMARY
- On October 20,1992,(57 l'R Regulatory Commission Washington, Precise Flight, Inc.,63120 Powell Dutte 4780?} the NRC published for public DC 2n555, telephone (301) 492-3918 Road, Bend, Oregon 97701. This !
mmment a proposed rule to update the concerning other siting anpoets. Inf mation may be examined et the mterf a used in decisions .egarding
- FAA Transport Airplane Dsrectorate, a , Marpand Ms 22d day 1601 Lind Avenue, SW., Renten, power reactor siting, including ryologic, ',
l nismic, and earthgaake engineeriny, ' Washington. l h.r the im.unir %m huru.am . musiderations for future nuclear power pog rug 73gg is,ongaring cn,,,3cy; y,, pants. The comment pericd for this h m d 1. G le, Shda L Maria lo. Aerreoace End ne8F, i . pt oposed rule was to have expired on Sect-fary of the Commimca Seattle Aircraft Certificetion Ofhen, f%:uary 17,1993, 11 R Doc.1r3-0%9 Pded 3-25-93; DE aml Sp+(Ial On66cution lirasxli, ANP.!- On January 5,1993 the public a coo, mg 190S, FAA, Transport Airplace u nment period was extended to March Directorats,1601 Lind Avenuo, SW., j 24,1993 (58 FR 271). The Commission Renton, Washington 98055-4058, has received a request to once again telephone (206) 227-2599, fax (206) extend the public comment period 227-1181. l l
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