ML18017A966

NRC Comments on American Society of Mechanical Engineers (Asme)/American Nuclear Seismic Probabilistic Risk Assessment (PRA) Code Case

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Staff Comments on the American Society of Mechanical Engineers (ASME)/American Nuclear Society (ANS)

Seismic Probabilistic Risk Assessment (PRA) Code Case The Table below provides the U.S. Nuclear Regulatory Commission (NRC) staffs comments on requirements in the Code Case.

Only those requirements where the staff has an objection is provided. A discussion of the staffs concern (issue) and the staff resolution is provided. The staff clarification or qualification to the requirement is indicated in the proposed staff resolution where new text is represented in bold typeface (i.e., bold) and deleted text is represented with a strikeout (i.e., strikeout). The staff resolutions represent the changes that need to be made to the requirement (as written in the ASME/ANS Code Case) for interim use of the Code Case.

ID Index Issue Proposed Staff Resolution 1 Section The last paragraph of the section states that the The approach to any external hazard PRA typically uses as its starting point 5-1.3 internal events PRA model is the starting point to the internal-events PRA model to which must be added a number of which must be added a number of structures, structures, systems, and components (SSCs) not included in the model but systems, and components (SSCs) not included in that could fail due to the external hazard and new failure modes caused by the model but that could fail due to the external the external hazard for SSCs already present in the model. Both the part hazard. Failure modes caused by the external of the internal-events model dealing with CDF and the part dealing with LERF hazard for SSCs existing in the internal events PRA are used as starting points.

should also be included.

2 Section The Part 5 Code Case does not include the Include in the NMA language on the use of generic fragility information as in 5-1.6 language from Section 5-1.6 in ASME/ANS RA-Sb- Section 5-1.6 in ASME/ANS RA-Sb-2013 as follows:

2013, which discussed the usage of generic fragility information. Section 5-1.6 in ASME/ANS RA-Sb- (a) Analysts should apply caution in the use of generic fragilities and 2013 indicates that (a) Analysts should apply provide justification that the generic fragilities are applicable, and (b) caution in the use of generic fragilities and provide Peer reviews should focus on the use of generic fragilities to ensure that justification that the generic fragilities are applicable, their use is appropriate and justified.

and (b) Peer reviews should focus on the use of generic fragilities to ensure that their use is appropriate and justified. These statements are important because they appropriately identify the scope of interest with respect to generic fragility for both the analysts and the peer-reviewers.

Enclosure

ID Index Issue Proposed Staff Resolution 3 Section Text was removed from Section 5-2 that helps set 5-2, third the context for the standard requirements. Seismic PRA is an integrated activity requiring close interactions among paragrap specialists from different fields (e.g., seismic hazard analysis, systems h analysis, and fragility evaluation). For this reason, it is important that all members of the seismic PRA team be cognizant of all of the SRs in this Part, not just those in their area of expertise, and understand the interactions required between the elements. The analysis requires judgment and extrapolation beyond observed data. Therefore, the analyst is strongly urged to review published seismic PRA reports and to compare his/her plant-specific seismic PRA to the published studies of similar reactor types and system designs. This understanding of the Standard and other seismic PRAs will promote consistency among similar PRAs and risk-informed applications and will also promote reasonableness in the numerical results and risk insights. The peer review is also directed in part toward this same objective reasonableness in the numerical results and risk insights.

4 Section 5- The first full paragraph of Section 5-2.1 states in 2.1 part, The requirements described in Part 5-2.1 The requirements described in Part 5-2.1 address these objectives in address these objectives in detail. A probabilistic detail. A probabilistic seismic hazard analysis (PSHA), which may directly seismic hazard analysis (PSHA), which may directly incorporate site response analyses, is used to assess horizontal ground incorporate site response analyses, is used to motions at the site.

assess horizontal ground motions at the site. It does not seem appropriate to highlight a specific aspect of the PSHA, particularly in such an ambiguous manner.

ID Index Issue Proposed Staff Resolution 5 General The Code Case proposes definitions for the terms Comment primary hazard and Secondary hazard. However,

• Ensure consistent use of the term secondary hazards with the s on the the Code Case only uses the term primary hazard in definition.

SHA the definition of the term secondary hazard, which

• To the extent possible express which secondary seismic hazards are Technical may not prompt a need to define the term primary included or, alternatively, which are not.

Element hazard. The primary hazard described by the objectives in Section 5-2.1 seems to be the vibratory ground motion. However, in many instances, but not all, the text refers to secondary hazards from vibratory ground motions but not always. It is unclear whether there is a difference between the way vibratory ground motion is referred to or if these are intended to be synonymous.

Consideration should be given to whether the definition be made more precise to the hazards, primary or secondary, that the Code Case intends to address. For example, does it intend to address tsunamis and seiches? If not, it should not be mentioned.

6 Table 5- The language of the high level requirement The basis for the calculation of Tthe frequencies of exceeding different 2.1-1, (HLR) HLR-SHA-A states, The frequency of levels of vibratory seismic ground motion at the site shall be based on a HLR- seismic ground motion at the site shall be based site-specific PSHA that represents the center, body, and range of the SHA-A on a site-specific PSHA that represents the technically defensible interpretations. The level of analysis, as well as the center, body, and range of the technically level of updates when an existing study is the initial basis for the site-specific defensible interpretations. The level of analysis, PSHA, shall be determined based on the intended application and on the as well as the level of updates when an existing technical viability of existing PSHA models.

study is the initial basis for the site-specific PSHA, shall be determined based on the intended application and on the technical viability of existing PSHA models. This language is too vague. In particular, the frequency of the ground motion is a natural process. It is their calculation that is based on a PSHA.

ID Index Issue Proposed Staff Resolution 7 Table 5- Note (1) of Table 5-2.1-2 states in part, The The appropriate level of the hazard analysis will depend on 2.1-2, appropriate level of the hazard analysis will project-specific factors and should include considerations such as the safety Note (1) depend on project-specific factors and should significance of the nuclear power plant, the technical complexity and include considerations such as the safety uncertainties in hazard inputs., regulatory oversight and requirements, and significance of the nuclear power plant, the the availability of resources.

technical complexity and uncertainties in hazard inputs, regulatory oversight and requirements, and the availability of resources. Although it is a note and not a requirement, citing the availability of resources as a means of determining the appropriate level of hazard analysis may be misconstrued as a justification for excluding consideration of a safety issue.

8 Table 5- Remove the following language in Note (1) of Table 5-2.1-2:

Note (1) of Table 5-2.1-2 refers to Regulatory 2.1-2, Guide (RG) 1.208 as providing an acceptable RG 1.208 [5-3] provides one acceptable approach to establishing a Note (1) approach to establishing a lower-bound magnitude for use in the hazard analysis.

lower-bound magnitude for use in the hazard analysis. However, the NRC staff has discouraged use of the damage parameter cumulative absolute velocity (CAV) filter in place of a lower-bound magnitude for the PSHA. Use of CAV has often been misapplied in PSHAs to improperly filter out larger magnitude events at larger source-to-site distances. Recently completed PSHAs for Near Term Task Force (NTTF) Recommendation 2.1 and combined operating license (COL) and early site permit (ESP) applications no longer use the CAV damage parameter in place of a lower-bound magnitude. NRC staffs related letter pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Section 50.54(f) specified use of M5 (moment magnitude 5) as an appropriate lower-bound magnitude.

ID Index Issue Proposed Staff Resolution 9 Table 5- Regarding supporting requirement SHA-A5 in JUSTIFY the specified lower-bound magnitude (or probabilistically defined 2.1-2, Table 5-2.1-2, the NRC staff has discouraged use characterization of magnitudes based on a damage parameter) for use in the SHA-A5 of the damage parameter cumulative absolute hazard analysis, such that earthquakes of magnitudes less than this value velocity (CAV) filter in place of a lower-bound are not expected to cause significant damage to the engineered structures or magnitude for the PSHA. Use of CAV has often equipment.

been misapplied in PSHAs to improperly filter out larger magnitude events at larger source-to-site distances. Recently completed PSHAs for Near Term Task Force (NTTF) Recommendation 2.1 and combined operating license (COL) and early site permit (ESP) applications no longer use the CAV damage parameter in place of a lower-bound magnitude. NRC staffs related letter pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Section 50.54(f) specified use of M5 (moment magnitude 5) as an appropriate lower-bound magnitude.

10 Table 5- ENSURE that the data and information are sufficient to characterize Sole use of term attenuation in 2.1-3, conjunction with modeling ground motions attributes important for modeling both regional propagation attenuation of SHA-B3 is unnecessarily limiting. ground motions and local site effects including their associated uncertainties.

11 Table 5- The current language requires a demonstration If an existing PSHA is used, DEMONSTRATE that an updated catalog of 2.1-3, that the updated earthquake catalog has been earthquakes was reviewed in the evaluation to determine if does not make the SHA-B5 reviewed if an existing PSHA is used. However, existing PSHA remains unviable.

this does not include accounting for the impact of the updated earthquake catalog on the existing PSHA.

ID Index Issue Proposed Staff Resolution 12 Table 5- In the ground motion characterization model that determines the range of The ground motion characterization model 2.1-5, needs to include the interface with site response seismic vibratory ground motion that can occur at a site, INCLUDE SHA-D1 analysis in terms of a reference soil or rock (a) credible mechanisms governing estimates of vibratory ground horizon, as defined by shear wave velocity, motion that can occur at a site, density, and damping values. (b) a review of available historical and instrumental seismicity data (including strong motion data) to assess and calibrate the model, and (c) applicable (existing and/or newly developed) ground motion prediction equations for the ground motion estimates,.

(d) reference soil or rock horizon (defined by shear wave velocity, density, and damping values).

13 Table 5- ENSURE that uncertainties are included in the model that determine the The ground motion characterization model 2.1-5, should include ground motion prediction range of seismic vibratory ground motion that can occur at a site as well as SHA-D3 equations (GMPEs) with alternative distance and alternative magnitude and distance scaling behaviors in accordance with magnitude scaling behaviors, not just a range of the level of analysis identified for HLR-SHA-A and the data and information in amplitudes. the update of the PSHA.

14 Table 5-The term ENSURE is not the appropriate action JUSTIFY ENSURE that the approach used to incorporate the site response 2.1-6, verb. analysis into the hazard analysis is justified(e.g., sources of soils and rock SHA-E3 material properties used in the analysis, uncertainties in site characterization and material properties, data to identify the depth to bedrock, appropriateness of one- two- or three-dimensional analysis in relation to the site stratigraphy).

15 Table 5- The supporting requirement uses the terms For those secondary hazards that are not screened out, INCLUDE their 2.1-10, hazards and secondary hazard interchangeably, effect through assessment of the frequency of hazard occurrence and the SHA-I2 which is potentially confusing. magnitude, when applicable, of the secondary hazard.

16 Table 5- The last sentence of Note (2) in Table 5- The appropriate approach used to justify the basis and methodology used 2.1-10, 2.1-10 is vague and unnecessary. for screening out secondary hazards is hazard- and site-specific.

Note (2) Justification may be based on available public literature and prior hazard studies.

ID Index Issue Proposed Staff Resolution 17 Table 5- The intent of supporting requirement SFR-A1 The NMA already discusses the overall intent of SFR-A1 and distinguishes 2.2-2, needs additional clarification. between failure mechanism and failure mode. Include in the NMA a SFR-A1 discussion such as:

The intent of SFR-A1 is to ensure that the fragility analyst provides fragility assessments for the SSCs defined by the systems analyst in the plants SEL and for the relevant failure modes associated to the basic PRA events. The understanding is that fragility assessments relate to failure mechanisms, which, in turn, relate to failure modes defined by the systems analyst.

18 Table 5- INCLUDE information relevant to justifying the modeling of fragility The information to be included should be such dependency correlation of SSCs and its basis (e.g., similarity of component 2.2-2, that it can justify the modeling of SSCs as SFR-A2 construction and location, and response spectra at the locations) to correlated from a fragility perspective and not support SPR-B4.

simply be relevant. Justification, more than the examples provided, will be necessary for any correlation other than 0 and 1.

Additionally the phrase fragility correlation should be replaced with fragility dependence.

Dependence between random variables characterize their interrelationship. Correlation (coefficient) is used to define the dependence structure between random variables. It is also lacking criteria for acceptability of a correlation model.

19 Table 5-The action verb ESTIMATE implies using If median-centered response analysis is performed, CALCULATE the 2.2-3, judgement or qualitative measures which are median response (i.e., structural loads and floor response spectra) and SFR-B4 inconsistent with the intent of the SR. The action ESTIMATE the variability in the response.

verb CALCULATE involves a mathematical process whereas the action verb ESTIMATE does not necessarily involve a calculation (e.g.,

quantification of a probability or frequency) and can be derived qualitatively.

ID Index Issue Proposed Staff Resolution 20 Table 5-In the 2009 revision (SFR-C2), part of the SR If probabilistic response analysis is performed to calculate structural loads 2.2-3, asked one to ACCOUNT for the entire spectrum and floor response spectra, ENSURE that the number of simulations done SFR-B6 of input ground motion levels displayed in the (e.g., Monte Carlo simulation or Latin Hypercube Sampling) is large enough seismic hazard curves. This sentence is removed to calculate stable responses. ACCOUNT for the entire spectrum of input in the code case. However, this sentence also ground motion levels displayed in the seismic hazard curves.

ensures the quality of the results of the probabilities response analysis 21 Table 5-The intent is to provide the basis and SPECIFY the basis and methodologies established for the 2.2-4, methodology to justify that the capacity of the capacity-based screening for the level defined in SPR-B5 (e.g., use of SFR-C1 SSC exceeds the screening level. simplified fragility analysis, use of applicable generic fragility or qualification data or earthquake experience, and use and applicability of EPRI fragility screening guidance are examples).

22 Table 5-In ASME/ANS RA-Sa-2009, Note (2) of the Add the language from Note (2) of supporting requirement SFR-B2 from 2.2-4, corresponding supporting requirement (i.e., SFR- ASME/ANS RA-Sa-2009 in the non-mandatory appendix for SFR-C2 to SFR-C2 B2) indicates that the screening criteria do not clarify whether those specific screening criteria are applicable to high apply to high-seismic regions such as coastal seismic region or not.

California. However, SFR-C2 in the Code Case does not discuss this note.

23 Table 5-The intent is to provide the basis to justify that SPECIFY JUSTIFY the basis for screening of inherently rugged components 2.2-4, the capacity of the SSC is inherently rugged. (e.g., applicability of fragility or qualification test data, earthquake SFR-C2 experience, past fragility analysis for similar SSCs and seismic responses, applicable EPRI guidance).

24 Table 5-Additional clarification is needed regarding In the NMA, address:

2.2-4, what is meant by the term inherently rugged - The term inherently rugged refers to seismic capacities well beyond the SFR-C2 component. risk-significant level.

- Typical items include manual valves, check valves, and small, in-line strainers.

- - The SPID (guidance for NTTF Recommendation 2.1 response) includes extensive discussions on the meaning of inherently rugged and many other fragility topics. (Refer to the SPID.)

ID Index Issue Proposed Staff Resolution Table 5-25 2.2-5, In general, the walkdown AND the fragility IDENTIFY seismic vulnerabilities low seismic capacities and to ensure SFR-D3, evaluation provide the assurance. This ENSURE that assumptions and the use of generic seismic fragilities are CC I requirement supports that assurance but may not conservative.

always ensure. Also, vulnerability needs to be defined.

Table 5-26 2.2-5, The current language implies realistic and plant IDENTIFY seismic vulnerabilities to ensure and ENSURE that the seismic SFR-D3, specific fragilities for all vulnerabilities, which is fragility calculations fragilities for SSCs that contribute significantly to CCII inconsistent with SFR-E3 and established seismic CDF or seismic LERF are can be realistic and plant-specific as practice. needed.

Table 5-27 2.2-5, The walkdown should also focus on FOCUS on potential functional and structural failure modes, equipment SFR-D4 operator pathways and potential anchorage, and support load paths, and pathways necessary for unavailability of those pathways performing required ex-control room actions.

SFR-D7 seems to refer to consequences of failure of one SSC on the performance of another SSC including inoperability of the SSC by and operator action. However, the words added here refer to pathways for ex-control room actions.

28 Table 5-2.2-5, This supporting requirement appears to pre- IDENTIFY potential risk-significant credible seismic interactions including SFR-D7 judge which seismic interactions have the proximity impacts, falling hazards, and differential displacements (e.g., failure potential to be risk-significant prior to the and falling of masonry walls and nonseismically designed SSCs, impact walkdown. If the intent is that such information between cabinets, differential building displacements). and EVALUATE the will be provided to the walkdown team by the consequences of such interactions on SSCs contained in the systems model plant-systems analyst it appears to be premature and on the credited operator actions. (See HLR-SPR-D.)

to expect such information to be available at the time of walkdown. Further, such an intent or appearance of intent can lead to an argument for excluding the plant-systems analyst from the walkdown. The second part of the SR starting with EVALUATE the consequences is expected to capture the risk-importance of the identified interactions.

ID Index Issue Proposed Staff Resolution 29 Table 5-2.2-5, In 2009 (SFR-E3) indicates that if component Add the following or equivalent as a new SFR-D6:

HLR- screened out during or following the walkdowns, document anchorage calculation and provide the IDENTIFY credible seismic-induced failure for the fire sources provided in SFR-D SPR-C4. If components are screened out during or following the basis. However, this statement is removed in the code case and it is not clear if screening out walkdown, PROVIDE the basis justifying such a screening.

equipment during walkdowns is allowed.

30 Table 5- The intent of the requirements should be to 2.2-6, For SSCs identified in SPR-C4SPR-C6 that significantly contribute to identify. In CCI conservative assumptions seismic core damage frequency and/or seismic large early release SFR-E2, and data may be used.

CC I frequency, conservatively IDENTIFY relevant failure modes mechanisms of structures, equipment, and soil. ENSURE that the assumptions and data used in the identification are conservative.

Table 5- For those SSCs identified in SPR-C4SPR-C6 that significantly contribute to 31 The examples listed in the requirement confuse 2.2-6, seismic core damage frequency and/or seismic large early release SFR-E2, the understanding of the differences between CCI and CCII. The only real difference is that frequency, IDENTIFY relevant and realistic failure mechanisms modes of CC II structures, equipment, and soil.

CCI says conservatively IDENTIFY relevant while CCII says IDENTIFY relevant and realistic. This SR also references SPR-C4, but should reference SPR-C6.

Table 5-32 The SR (CC I and II) refers to SPR-B6 for For CCI:

2.2-6, SFR-E5, identification purposes. SPR-B6 discusses relay ESTIMATE contact-chatter seismic fragilities for relays or other similar CCI and II or other similar devices. This SR also needs to devices that are identified in the systems analysis. (See SPR-B6.)

capture or other similar devices which is currently missing not only for consistency but For CCII:

also to prevent any implication that other similar devices need not be considered here. CALCULATE contact-chatter seismic fragilities for relays or other Additionally, the action verb for the second part similar devices that are identified in the systems analysis (see of the CC II requirements needs to be capitalized SPR-B6) that significantly contribute to seismic core damage frequency to identify it. and/or seismic large early release frequency.

ID Index Issue Proposed Staff Resolution 33 Table 5-2.2-6, The action verb for the second part of the CALCULATE seismic fragilities for credible seismic-induced flood sources SFR-E6, CC II requirements needs to be capitalized (see SFR-D5) and seismic-induced fire sources (see SFR-D6) that CCII to identify it. Calculate is the appropriate significantly contribute to seismic core damage frequency and/or seismic action verb to be used for this supporting large early release frequency. For those flood and fire sources that do not requirement. significantly contribute to seismic core damage frequency and/or seismic large early release frequency, estimate ESTIMATE the seismic fragilities.

34 Table 5-2.2-7, Related Table 5-2.2-6 that provides supporting Regarding list item (i) in SFR-F2:

SFR-F2 requirements associated with calculation of seismic-fragility parameters use distinct action (i) estimation or calculation of fragility parameter values for each SSC verbs ESTIMATE and CALCULATE, modeled (median capacity, logarithmic standard deviation reflecting the respectively, for Capability Category I and randomness in median capacity, and logarithmic standard deviation Capability Category II. However, the related representing the uncertainty in median capacity), and supporting requirement SFR-F2, item (i) associated with documentation of fragility parameter values only uses the word estimation, but not calculation. Therefore, the documentation supporting requirement item (i) is partly inconsistent with other related supporting requirements.

35 Section 5-2.3 The seismic PRA depends on both It is assumed:

Seismic the capability and completeness of the internal events at-power PRA.

• Relative to the systems-analysis requirements contained herein, the Plant seismic PRA analysis team possesses a full-scope internal events, at-Response power Level 1 and Level 2 LERF PRA, developed either before or Analysis concurrently with the seismic PRA.

(SPR),

Second

• The internal-events PRA is then used as the basis for the seismic PRA list systems analysis.

• It is recognized that the capability and completeness of the seismic PRA is a function of the capability and completeness of the internal events at-power PRA.

ID Index Issue Proposed Staff Resolution 36 Section 5-2.3 The sentence reads like a how to which is not A general methodology for the modeling and quantification of a seismic PRA Seismic the intent of the Standard. Further, none of the is documented in references such as EPRI-3002000709 [5-5], EPRI-1020756 Plant references cited in the Section are endorsed by [5-6], and EPRI-1025294 [5-7].

Response the staff. Such references should be moved to Analysis the NMA portion of the Standard.

(SPR) 37 Section 5- Cross-references in SFR to SPR (ensure 2.3 Include the missing cross-references either in the requirements or that they also are in SPR). footnotes Seismic Plant SPR-B4 includes the reference to SFR-A2 Response SPR-B5 includes the reference to SFR-C1 Analysis (SPR) SPR-C4 does not cross-reference SFR-D6 SPR-D does not cross-reference SFR-D7 38 Table 5-2.3-2 It is unclear whether the SR is seeking to Using a systematic process, IDENTIFY credible seismically induced initiating SPR-A2 identify all possible initiating events from events caused by secondary hazards (e.g., seismically induced internal secondary hazards or if the intent is to flooding, external flooding, and fire) including those identified in SHA-I2 for identification and screen such initiators for consideration retention in the plant-response analysis and model inclusion in the plant-systems model. development process.

39 Table 5-2.3-2 The verb encompasses is overly severe and REVIEW plant-specific response to past seismic events, as well as other SPR-A3 cannot reasonably be achieved in practice. The available seismic risk evaluations for nuclear plants, to ensure that the list of wording of this SR should be similar to IE-A3 and initiating events included in the evaluation encompasses accounts for IE-A4. industry experience.

Table 5-40 The plant-response analysis should include all INCLUDE in the plant-response analysis the events identified in SPR-2.3-2 SPR-A4 identified events. A1, and SPR-A2, and SPR-A3 above.

41 Table 5-2.3-3 Due to the input from the fire and internal ENSURE that the peer review findings for the internal-events and other SPR-B2 flooding PRAs, and possibly other hazard hazard PRAs that are relevant to the seismic PRA are resolved and that the PRAs, in addition to internal events the findings disposition does not adversely affect incorporated into the development of from all relevant PRAs should be appropriately the seismic PRA plant-response model.

dispositioned. Additionally, it is not clear what is intended by the latter part of this SR (does not adversely affect).

ID Index Issue Proposed Staff Resolution Table 5-42 2.3-3 Incorrect reference to SPR-C4 instead of SPR-C6. INCLUDE seismically induced failures representing the failure modes of SPR-B3 interest in the seismic PRA plant-response model (e.g., tank rupture, pump failure to start/run, etc.). (See SPR-C4SPR-C6.)

43 Table 5-2.3-3 The justification for the appropriate capacity SPECIFY JUSTIFY (e.g. based on the contribution to the risk SPR-B5 based screening level needs to be provided. quantification) an appropriate the set of criteria to be used in support of the Neither the action verb for this SR nor that used screening of SSC failure modes on the basis of fragility. (See SFR-C1.)

for SFR-C1 achieves that purpose.

44 Table 5-2.3-3 The term with a significant contributor to USE a systematic approach to INCLUDE in the system analysis the effects SPR-B6 CDF or LERF is not defined. How can one of those relays or similar devices susceptible to contact chatter whose determine the significance without performing contact chatter results in the unavailability or spurious actuation of SSCs on the calculation? the seismic equipment list. with a significant contribution to CDF or LERF.

45 Table 5-2.3-1 The term operator performance can be Human actions credited in the seismic PRA shall consider HLR- interpreted in a narrow context to mean only in- seismic-specific challenges to operator performance actions included in SPR-D control room actions and performance. the seismic PRA.

However, the HLR and the corresponding SRs are applicable to all human actions included in This comment is not for a SR but for the HLR.

the SPRA.

ID Index Issue Proposed Staff Resolution 46 Table 5-2.3-5 Cue availability as well as dependencies are For CCI:

SPR-D3 integral part of HRA analyses and maybe affected by seismic events CALCULATE the HEPs for all HFEs taking into account relevant seismic-related effects on control room and ex-control room post-initiator actions in accordance with the SRs for HLR-HR-G in Part 2 of this Standard as set forth under Capability Category I. In addressing influencing factors and the timing considerations covered in SRs HR-G3, HR-G4, and HR-G5 in Part 2, attention is to be given to how the seismic event alters any previous assessments in nonseismic analyses including: additional workload and stress; effects of the seismic event on mitigation, cue availability, dependencies, required response, timing, accessibility, and potential for physical harm; and seismic-specific job aids and training.

For CCII:

CALCULATE the HEPs for all HFEs taking into account relevant seismic-related effects on control room and ex-control room post-initiator actions in accordance with the SRs for HLR-HR-G in Part 2 of this Standard as set forth under Capability Category II. In addressing influencing factors and the timing considerations covered in SRs HR-G3, HR-G4, and HR-G5 in Part 2, attention is to be given to how the seismic event alters any previous assessments in nonseismic analyses including: additional workload and stress; effects of the seismic event on mitigation, cue availability, dependencies, required response, timing, accessibility, and potential for physical harm; and seismic-specific job aids and training.

ID Index Issue Proposed Staff Resolution Table 5-47 2.3-5 The action verb ESTIMATE implies using For significant HFEs, ESTIMATE DETERMINE the timing aspects of the SPR-D4 judgement or qualitative measures only which are response actions (i.e., time of relevant indication, time available to complete inconsistent with the intent of the SR. Some of action, and time required to complete action) recognizing the sequence of the examples of approaches provide more events and expected seismic conditions based on one or a combination of information than an estimate. the following approaches:

(a) Walk-throughs or talk-throughs of procedures with plant operations or training personnel (b) Simulator observations (c) Plant-specific thermal-hydraulic analyses (d) Realistic and applicable generic or similar plant thermal-hydraulic analyses.

Based on a review of procedures with plant operations or training personnel and recognizing the sequence of events and expected seismic conditions, CONFIRM for nonsignificant HFEs the timing aspects of the response actions.

48 Table 5-2.3-6 The phrase dominant sequence insights is not USE the quantification process to ensure that the components screened SPR-E4 defined in either Addendum A or Addendum B. out, based on the screening level defined in SPR-B5, do not become a Use of the term dominant was decided not to significant contributor or do not invalidate the dominant significant be used anywhere in the standard. sequence insights of the seismic PRA.

49 Table 5-2.3-6 It is not possible or necessary to quantify all QUANTIFY the mean core damage frequency and large early release SPR-E5, uncertainties. frequency and propagate the parameter uncertainty that results from each CC-II input (i.e., the seismic hazard, the seismic fragilities, and the systems analysis).

50 Table 5-2.3-6 The reference to Part 2 is missing for HLR-QU-E For CC II:

SPR-E7 for CCII.

PERFORM the uncertainty analysis consistent with HLR-QU-E of Part 2 addressing key assumptions in the hazard analysis (see SHA-J2),

fragility analysis (see SFR-F3), and system modeling for Capability Category II.

Table 5-51 2.3-1 This HLR is overly broad since HLR-SHA-J and Documentation of the seismic PRA analysis plant-response model HLR- HLR-SFR-F already address documentation of shall be consistent with the applicable supporting requirements.

SPR-F the seismic hazard evaluation and the seismic-fragility evaluation, respectively.

ID Index Issue Proposed Staff Resolution Table 5-52 2.3-7 The Code Case needs to specify the type of DOCUMENT the process used in the seismic plant-response analysis and SPR-F2 documentation to be provided, rather than quantification, including. For example, this documentation typically relying on the discretion of the user. includes a description of