NL-17-1201, Response to Supplemental Information Needed for Acceptance of Systematic Risk-Informed Assessment of Debris Technical Report

Response to Supplemental Information Needed for Acceptance of Systematic Risk-Informed Assessment of Debris Technical Report

ML17192A245
Person / Time
Site:	Vogtle
Issue date:	07/11/2017
From:	Hutto J Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-17-1201
Download: ML17192A245 (47)

Text

J. J. Hutto 40 Inverness Center Parkway Regulatory Affairs Director Post Office Box 1295 Birmingham, AL 35242 205 992 5872 tel 205 992 7601 fax jjhutto@southernco.com July 11, 2017 Docket Nos.: 50-424 NL-17-1201 50-425 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant Units 1 & 2 Response to Supplemental Information Needed for Acceptance of Systematic Risk-Informed Assessment of Debris Technical Report Ladies and Gentlemen:

By letter dated April 21, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17116A096), Southern Nuclear Operating Company (SNC) submitted a technical report for approval for Vogtle Electric Generating Plant, Units 1 and 2. In addition, the letter provided a supplemental response to Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors" (ADAMS Accession No. ML042360586) that supersedes previous responses. The technical report contains a risk-informed methodology to evaluate debris effects, except for vessel fiber limits.

By letter dated June 26, 2017, (ADAMS Accession No. ML17166A433), the Nuclear Regulatory Commission (NRC) staff requested information regarding the seismic probabilistic risk assessment peer review. The Enclosure provides the SNC response to the NRC request. In addition, the NRC staff asked SNC to confirm the scope of the requested technical report review. To clarify, SNC requests NRC review and approval of Enclosures 1 - 5 from the April 21, 2017 technical report. While SNCs intent is that the Enclosures can be separated for review by the appropriate NRC branch, they are intertwined such that NRC approval of all five is necessary for SNCs final resolution of Generic Letter (GL) 2004-02.

This letter contains no NRC commitments. If you have any questions, please contact Ken McElroy at 205.992.7369.

U. S. Nuclear Regulatory Commission NL-17-1201 Page2 Mr. J. J. Hutto states he is Regulatory Affairs Director of Southern Nuclear Operating Company, is authorized to execute this oath on behalf of Southern Nuclear Operating Company and, to the best of his knowledge and belief, the facts set forth in this letter are true.

Respectfully submitted, J. J. Hutto Regulatory Affairs Director JJH/RMJ Swam to ~nd subscribed before me this 11_ day of~"--\~ 12017, otary Public

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Enclosure:

SNC Response to NRC Request Regarding Risk-Informed Methodology cc: Regional Administrator, Region II NRR Project Manager- Vogtle 1 & 2 Senior Resident Inspector- Vogtle 1 & 2 State of Georgia Environmental Protection Division RType: CVC7000

Vogtle Electric Generating Plant Units 1 & 2 Response to Supplemental Information Needed for Acceptance of Systematic Risk-Informed Assessment of Debris Technical Report Enclosure SNC Response to NRC Request Regarding Risk-Informed Methodology

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology NRC Information Request:

Regulatory Guide 1.200, Rev. 2, An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities (ADAMS Accession No. ML090410014) describes an approach for determining whether the technical adequacy of a PRA is sufficient to provide confidence in the results; it also describes information the NRC staff expects to be included in risk-informed submittals. As discussed in the guide, a risk informed submittal should contain discussions concerning peer review. If the peer review is not performed against the established standards, then information needs to be included in the submittal demonstrating that the different criteria used are consistent with the established standards. The risk-informed methodology described in the technical report should include the following:

x Description demonstrating that the criteria in ASME/ANS RA-Sb-2013 (Addendum B), which is not an established endorsed standard, are consistent with the ASME/ANS RA-Sa-2009 (Addendum A), which is an established endorsed standard, for the seismic probabilistic risk assessment peer review facts and observations.

x If the different criteria are not consistent with the established endorsed standard, an explanation demonstrating that the analogous Addendum A supporting requirements have been met.

SNC Response:

Regulatory Guide 1.200, Revision 2.0 endorses ASME/ANS RA-Sa-2009 (Addendum A) but, as noted in an NRC letter to ASME, does not endorse PRA Standard ASME/ANS RA-Sb-2013 (Addendum B). The Vogtle Electric Generating Plant, Units 1 and 2 (Vogtle) Seismic Probabilistic Risk Assessment (SPRA) peer review was performed using the SPRA requirements in Addendum B.

Because the peer review was not performed against the NRC endorsed standard, information demonstrating that any different criteria used are consistent with the NRC endorsed standard is provided here. The following discussion addresses the differences relative to establishing the technical capability of the Vogtle SPRA.

The ASME/ANS PRA Standard Part 5 requirements for at-power seismic PRA (in all versions of the PRA Standard) are organized into the following three major technical elements:

x Seismic hazard analysis (technical element SHA) x Seismic fragility analysis (technical element SFR), and x Seismic plant-response modeling (technical element SPR)

Each technical element contains several high level requirements (HLR) and associated supporting requirements (SR). The following three tables (Table 1 for SHA, Table 2 for SFR and Table 3 for SPR) provide SR by SR comparisons between Addendum A and Addendum B of the ASME/ANS PRA Standard. Differences between SR wordings are denoted in the following tables using bold type. Changes in the HLRs between Addendum A and Addendum B are denoted using strikethrough text. The comparison assessment focuses on capability category II (CCII); as such, SR text not related to CCII is not included in the following E-1

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology tables. This comparison assessment is performed by SR and not by HLR; peer reviewers assess technical quality by reviewing SRs (HLRs are not assigned technical capabilities). The following assessment conclusion categories are used in the SR comparison assessment:

x Addendum B Assessment Equates to Addendum A: This conclusion category is used when the SR wording of Addendum A and Addendum B are the same or effectively the same (i.e., re-wording that is for clarity and consistency and not intended to change the intent). This conclusion category is also used in cases where the wording differences are related to moving the requirements to another SR. In certain SRs the qualifier for a specific capability category range is assigned to indicate the focus on capability category II when there are differences in other capability categories. A peer reviewer using Addendum A or Addendum B would come to the same technical capability assessment on these topics.

x Addendum B Envelopes Addendum A: This conclusion category is used when the SR wording of Addendum A and Addendum B are different and the requirements of Addendum B envelope that of Addendum A (i.e., if the analysis meets Addendum B CCII then by definition it meets Addendum A CCII or higher). A peer reviewer using Addendum B would assess a technical capability on these topics that would be equal to or greater than what would be determined if Addendum A were used in the review.

x Vogtle Conforms to Addendum A: This conclusion category is used when the SR wording of Addendum A and Addendum B are different, or some of the requirements of Addendum A no longer exist in Addendum B, yet the analysis performed and documented in the Vogtle analysis conforms to the requirements of Addendum A as well as Addendum B.

x Vogtle Conforms to Accepted Current Practices: This conclusion category is used when the SR wording of Addendum A and Addendum B are different; or some of the requirements of Addendum A no longer exist in Addendum B because they were removed from the Standard as confusing or judged too specific how-to. For the one SR where this conclusion category applies, Vogtle does not follow some of the specifics of the Addendum A SR requirements but Vogtle does conform to accepted current practices.

While the Vogtle SPRA was peer reviewed against the ASME/ANS RA-Sb-2013 (Addendum B) requirements, the tables that follow demonstrate that most of the supporting requirements in Addendum B are consistent with the supporting requirements in ASME/ANS RA-Sa-2009 (Addendum A). For the few supporting requirements where differences are noted in the tables, the Vogtle SPRA model and documentation meet the analogous Addendum A supporting requirements. Therefore, the Vogtle SPRA meets the technical adequacy requirements of Regulatory Guide 1.200, Revision 2 and is of sufficient quality and level of detail to support the risk informed approach for GSI-191.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III HLR-SHA-A: The frequency of earthquakes at the site shall be based on a site-specific probabilistic seismic hazard analysis (existing or new) that reflects the composite distribution of the informed technical community. The level of analysis shall be determined based on the intended application and on site-specific complexity.

SHA-A1 ASME/ANS <not printed here; not In performing the probabilistic seismic hazard Addendum B Assessment Equates to RA-Sa- focus of this analysis (PSHA), BASE it on, and MAKE it Addendum A 2009 assessment> consist of, the collection and evaluation of available information and data, evaluation of The wording for this SR is the same for the uncertainties in each element of the Addendum A and Addendum B.

PSHA, and a defined process and documentation to make the PSHA traceable.

ASME/ANS Identical to Identical to Addendum A RA-Sb- Addendum A 2013 SHA-A2 ASME/ANS As the parameter to characterize both hazard <not printed here; not Addendum B CC1-III Assessment Equates RA-Sa- and fragilities, USE the spectral accelerations, focus of this to Addendum A CCI-II 2009 or the average spectral acceleration over a assessment>

selected band of frequencies, or peak ground In response to EPRI 2011 comment, acceleration. Addendum B removed the CCIII ASME/ANS Identical to Addendum A for CC I/II requirements. The Addendum B SR equates RA-Sb- to Addendum A CCI-II.

2013 SHA-A3 ASME/ANS In the selection of frequencies to determine spectral Addendum B Assessment Equates to RA-Sa- accelerations or average spectral acceleration, CAPTURE the Addendum A 2009 frequencies of those structures, systems, or components, or a combination thereof that are significant in the PRA results and Addendum B changed action verbs to be insights. consistent with accepted verb usage across ASME/ANS If spectral acceleration or average spectral acceleration over a SRs, and also made minor changes in RA-Sb- band of frequencies is used, INCLUDE the response frequencies of wordings. This wording edit does not change 2013 SSCs that are significant in the PRA results and insights. the capability category requirements of this SR.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III SHA-A4 ASME/ANS In developing the probabilistic seismic hazard analysis results, Addendum B Assessment Equates to RA-Sa- whether they are characterized by spectral accelerations, peak ground Addendum A 2009 accelerations, or both, EXTEND them to large-enough values (consistent with the physical data and interpretations) so that the Addendum B added the phrase "for use in truncation does not produce unstable final numerical results, such as accident sequence quantification". This core damage frequency, and the delineation and ranking of seismic- wording edit does not change the capability initiated sequences are not affected. category requirements of this SR.

ASME/ANS In developing the probabilistic seismic hazard analysis results for use RA-Sb- in accident sequence quantification, whether they are characterized 2013 by spectral accelerations, peak ground accelerations, or both, EXTEND them to large-enough values (consistent with the physical data and interpretations) so that the truncation does not produce unstable final numerical results, such as core damage frequency, and the delineation and ranking of seismic-initiated sequences are not affected.

SHA-A5 ASME/ANS SPECIFY a lower-bound magnitude (or probabilistically defined Addendum B Assessment Equates to RA-Sa- characterization of magnitudes based on a damage parameter) for Addendum A 2009 use in the hazard analysis, such that earthquakes of magnitude less than this value are not expected to cause significant damage to the The wording for this SR is the same for engineered structures or equipment. Addendum A and Addendum B.

ASME/ANS Identical to Addendum A RA-Sb-2013 HLR-SHA-B: To provide inputs to the probabilistic seismic hazard analysis, a comprehensive up-to-date database including geological, seismological, and geophysical data; local site topography; and surficial geologic and geotechnical site properties shall be compiled. A catalog of historical, instrumental, and paleoseismicity information shall also be compiled.

SHA-B1 ASME/ANS In performing the probabilistic seismic hazard <not printed here; not Addendum B Assessment Equates to RA-Sa- analysis (PSHA), BASE it on available or focus of this Addendum A 2009 developed geological, seismological, assessment>

geophysical, and geotechnical data that Addendum B changed action verbs to be reflect the current state of the knowledge and consistent with accepted verb usage across that are used by experts/analysts to develop SRs. This wording edit does not change the E-4

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III interpretations and inputs to the PSHA. capability category requirements of this SR.

ASME/ANS In performing the probabilistic seismic hazard <not printed here; not RA-Sb- analysis (PSHA), USE available or developed focus of this 2013 geological, seismological, geophysical, and assessment>

geotechnical data that reflect the current state of the knowledge and that are used by experts/analysts to develop interpretations and inputs to the PSHA.

SHA-B2 ASME/ANS ENSURE that the database and information <not printed here; not Addendum B Assessment Equates to RA-Sa- used are adequate to characterize all credible focus of this Addendum A 2009 seismic sources that may contribute assessment>

significantly to the frequency of occurrence of The wording for this SR is the same for vibratory ground motion at the site, Addendum A and Addendum B for CCI and considering regional attenuation of ground CCII.

motions and local site effects. If the existing probabilistic seismic hazard analysis (PSHA) studies are to be used in the seismic PRA, ENSURE that any new data or interpretations that could affect the PSHA are adequately incorporated in the existing data and analysis.

ASME/ANS Identical to Addendum A <not printed here; not RA-Sb- focus of this 2013 assessment>

SHA-B3 ASME/ANS <not printed here; not As a part of data collection, COMPILE a Vogtle Conforms to Addendum A RA-Sa- focus of this catalog of historically reported, geologically 2009 assessment> identified, and instrumentally recorded A catalog of historically reported, geologically earthquakes. USE reference [5-30] identified, and instrumentally recorded E-5

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III requirements or equivalent. earthquakes for the entire CEUS was ASME/ANS INCLUDE an appropriate existing catalog of <not printed here; not compiled by the 2012 CEUS SSC report.

RA-Sb- historically reported earthquakes, focus of this Following a SSHAC Level 3 process, the 2013 instrumentally recorded earthquakes, and assessment> CEUS SSC report is a robust evaluation of earthquakes reported through geological available information on historical seismicity, investigations. USE reference [5-30] paleoseismic data on large-magnitude requirements or equivalent. recurrence rates, and state-of-the-knowledge of earthquake seismic sources as considered in the informed technical community.

The 2012 CEUS SSC catalog followed a SSHAC Level 3 process and is applicable for risk informed applications. Compiling a new catalog will not be as rigorous as the SSHAC Level 3 process. The Addenda B SR requirement is appropriate for CC-II.

The 2012 CEUS SSC report used an earthquake catalog which extended through 2008. Recent earthquake activity in the vicinity of the Vogtle site was assessed for its impact on hazard. The study was based on a temporal update of the earthquake catalog from 2009 through February 2016. The assessment concluded that the 2012 CEUS SSC report seismicity parameters are appropriate for evaluation of seismic hazard at Vogtle. Based on this, the Vogtle PSHA that was performed conforms to Addendum A.

HLR-SHA-C: To account for the frequency of occurrence of seismic ground motions in the site region, the probabilistic seismic hazard analysis shall examine all credible sources of potentially damaging earthquakes.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III SHA-C1 ASME/ANS In the probabilistic seismic hazard analysis, EXAMINE all potential Addendum B Assessment Envelopes RA-Sa- sources of earthquakes that affect the probabilistic hazard at the Addendum A 2009 site. BASE the identification and characterization of seismic sources on regional and site geological and geophysical data, Addendum B added additional clarifications historical and instrumental seismicity data, the regional stress field, and requirements into the text of this SR, and and geological evidence of prehistoric earthquakes. also Addendum B changed action verbs to be ASME/ANS In the probabilistic seismic hazard analysis, EVALUATE sources of consistent with accepted verb usage across RA-Sb- earthquakes that have the potential to contribute significantly to SRs. The Addendum B SR wording 2013 the probabilistic hazard at the site. IDENTIFY and envelopes that of Addendum A.

CHARACTERIZE seismic sources taking into account previous compilations of seismic sources, based on regional and site geological and geophysical data, historical and instrumental seismicity data, and geological evidence of prehistoric earthquakes.

SHA-C2 ASME/ANS ENSURE that any expert elicitation process used to characterize the Addendum B Assessment Equates to RA-Sa- seismic sources is compatible with the level of analysis discussed in Addendum A 2009 Requirement HA-A, and FOLLOW a structured approach.

ASME/ANS ENSURE that any expert elicitation process used to characterize the Addendum B changed action verbs to be RA-Sb- seismic sources is compatible with the level of analysis discussed in consistent with accepted verb usage across 2013 Requirement HLR-SHA-A, and USE a structured approach. SRs. This wording edit does not change the capability category requirements of this SR.

SHA-C3 ASME/ANS <not printed here; not The seismic sources are characterized by Vogtle Conforms to Addendum A RA-Sa- focus of this source location and geometry, maximum 2009 assessment> earthquake magnitude, and earthquake Addenda B added additional clarification into recurrence. INCLUDE the aleatory and the text of this SR, and also added a clause epistemic uncertainties explicitly in these "where significant" at the end. The Addenda characterizations. B SR requirement is appropriate for CC-II.

Under the SSHAC Level 3 process the aleatory and epistemic uncertainties in E-7

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III ASME/ANS <not printed here; not The seismic sources are characterized by seismic sources are characterized for source RA-Sb- focus of this alternative source representation and location and geometry, magnitude, and 2013 assessment> source geometry, maximum earthquake activity rate. Logic trees to account for the magnitude, and earthquake recurrence. epistemic uncertainty were developed as part INCLUDE the aleatory and epistemic of the SSHAC Level 3 methodology uncertainties explicitly in these implemented in the CEUS SSC report. The characterizations, where significant. aleatory uncertainty was also accounted for in the PSHA framework of the Vogtle PSHA.

For seismic sources representing repeated large magnitude earthquakes (RLMEs),

uncertainties in location and geometry, magnitude model, activity rate, and maximum magnitude were explicitly included in the characterization. For background sources, uncertainty in geometry was represented with alternative sets of area sources, uncertainties in recurrence rates were represented with alternative rates, and uncertainties in maximum magnitude were represented with distributions of values. These uncertainties were documented in the 2012 CEUS SSC report and were included in the Vogtle PSHA.

Based on this, the Vogtle PSHA that was performed conforms to Addendum A.

SHA-C4 ASME/ANS If an existing probabilistic seismic hazard analysis study is used, Addendum B Assessment Equates to RA-Sa- SHOW that any seismic sources that were previously unknown or Addendum A 2009 uncharacterized are not significant, or INCLUDE them in a revision of the hazard estimates. Addendum B added additional clarifications and modified the sentence structure to ASME/ANS If an existing seismic source model is used, DEMONSTRATE that any highlight the seismic source model aspect of RA-Sb- new seismic sources that have been identified or were the PSHA. In addition, Addendum B changed 2013 uncharacterized when the existing models were developed are not action verbs to be consistent with accepted E-8

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III significant, or INCLUDE them in the update of the hazard estimates. verb usage across SRs. This wording edit does not change the capability category requirements of this SR.

HLR-SHA-D: The probabilistic seismic hazard analysis shall examine mechanisms influencing vibratory ground motion that can occur at a site given the occurrence of an earthquake of a certain type (e.g., strike slip, normal, reverse) and magnitude, and at a certain location.

Uncertainties shall be addressed in characterizing the ground motion propagation.

SHA-D1 ASME/ANS ACCOUNT in the probabilistic seismic hazard analysis for Addendum B Assessment Equates to RA-Sa- (a) credible mechanisms governing estimates of vibratory ground Addendum A 2009 motion that can occur at a site (b) regional and site-specific geological, geophysical, and Addendum B changed action verbs to be geotechnical data and historical and instrumental seismicity data consistent with accepted verb usage across (including strong motion data) SRs. In addition, Addendum B modified item (c) current attenuation models in the ground motion estimates (b) by removing requirements that were ASME/ANS In the vibratory ground motion analysis, INCLUDE redundant with SHA-B1. This wording edit RA-Sb- (a) credible mechanisms governing estimates of vibratory ground does not change the capability category 2013 motion that can occur at a site requirements of this SR.

(b) available historical and instrumental seismicity data (including strong motion data)

(c) current attenuation models for the ground motion estimates SHA-D2 ASME/ANS ENSURE that any expert elicitation process used to characterize the Addendum B Assessment Envelopes RA-Sa- ground motion is compatible with the level of analysis discussed in Addendum A 2009 Requirement SHA-A, and FOLLOW a structured approach.

ASME/ANS ENSURE that any expert elicitation process used to characterize the Addendum B added additional requirements RA-Sb- ground motion or any other elements of the ground motion into the text of this SR, and also Addendum B 2013 analysis is compatible with the level of analysis discussed in changed action verbs to be consistent with Requirement HLR-SHA-A, and USE a structured approach. accepted verb usage across SRs. The Addendum B SR wording envelopes that of Addendum A.

SHA-D3 ASME/ANS <not printed here; not ADDRESS both the aleatory and epistemic Addendum B Assessment Envelopes RA-Sa- focus of this uncertainties in the ground motion Addendum A 2009 assessment> characterization in accordance with the level of analysis identified for Requirement SHA-A. Addendum B changed action verbs to be E-9

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III ASME/ANS <not printed here; not INCLUDE both the aleatory and epistemic consistent with accepted verb usage across RA-Sb- focus of this uncertainties separately in the ground motion SRs, and also Addendum B added additional 2013 assessment> characterization in accordance with the level requirement on handling aleatory and of analysis identified for Requirement HLR- epistemic uncertainties separately. The SHA-A. Addendum B SR wording envelopes that of Addendum A.

SHA-D4 ASME/ANS If an existing probabilistic seismic hazard analysis study is used, Addendum B Assessment Equates to RA-Sa- SHOW that any ground motion models or new information that were Addendum A 2009 previously unused or unknown are not significant, or INCLUDE them in a revision of the hazard estimates. Addendum B added additional clarifications ASME/ANS If existing ground motion models are used, DEMONSTRATE that and modified the sentence structure to RA-Sb- new information not previously used or which was unknown when the highlight the ground motion model aspect of 2013 existing models were developed would not significantly affect the the PSHA. In addition, Addendum B changed PSHA results, or INCLUDE it in the update of the hazard estimates. action verbs to be consistent with accepted verb usage across SRs. This wording edit does not change the capability category requirements of this SR.

HLR-SHA-E: The probabilistic seismic hazard analysis shall account for the effects of local site response.

SHA-E1 ASME/ANS <not printed here; not ACCOUNT in the probabilistic seismic Addendum B Assessment Equates to RA-Sa- focus of this hazard analysis for the effects of site Addendum A 2009 assessment> topography, surficial geologic deposits, and site geotechnical properties on ground Addendum B changed action verbs to be motions at the site. consistent with accepted verb usage across ASME/ANS <not printed here; not In the probabilistic seismic hazard SRs. This wording edit does not change the RA-Sb- focus of this analysis, INCLUDE the effects of site capability category requirements of this SR.

2013 assessment> topography, surficial geologic deposits, and site geotechnical properties on ground motions at the site.

SHA-E2 ASME/ANS <not printed here; not ADDRESS both the aleatory and epistemic Addendum B Assessment Equates to RA-Sa- focus of this uncertainties in the local site response Addendum A 2009 assessment> analysis.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III ASME/ANS <not printed here; not INCLUDE both the aleatory and epistemic Addendum B changed action verbs to be RA-Sb- focus of this uncertainties in the local site response consistent with accepted verb usage across 2013 assessment> analysis. SRs. This wording edit does not change the capability category requirements of this SR.

HLR-SHA-F: Uncertainties in each step of the hazard analysis shall be propagated and displayed in the final quantification of hazard estimates for the site.

Addendum A only: The results shall include fractile hazard curves, median and mean hazard curves, and uniform hazard response spectra. For certain applications, the probabilistic seismic hazard analysis shall include seismic source deaggregation and magnitude-distance deaggregation SHA-F1 ASME/ANS <not printed here; not In the final quantification of the seismic Addendum B Assessment Equates to RA-Sa- focus of this hazard, INCLUDE and DISPLAY the Addendum A 2009 assessment> propagation of both aleatory and epistemic uncertainties. In response to NRC 2012 comment on ASME/ANS <not printed here; not In the final quantification of the seismic Addendum B ballot that said the wording of RA-Sb- focus of this hazard, INCLUDE uncertainties through a this SR was vague, Addendum B revised the 2013 assessment> family of hazard curves. wording to be clear that CCI is Mean only and that CCII-III is a family of hazard curves. This wording edit does not change the capability category requirements of this SR.

SHA-F2 ASME/ANS In the probabilistic seismic hazard analysis, INCLUDE appropriate Addendum B Assessment Equates to RA-Sa- sensitivity studies and inter mediate results to identify factors that are Addendum A 2009 important to the site hazard and that make the analysis traceable.

ASME/ANS Identical to Addendum A The wording for this SR is the same for RA-Sb- Addendum A and Addendum B.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III SHA-F3 ASME/ANS <not printed here; not DEVELOP the <not printed here; not Addendum B Assessment Equates to RA-Sa- focus of this following results as a focus of this Addendum A 2009 assessment> part of the assessment>

quantification Addendum B changed action verbs to be process, compatible consistent with accepted verb usage across with needs for the SRs, and also Addendum B added additional level of analysis clarification on the phrase "quantification determined in (HLR- process" by modifying it to "hazard SHA-A): quantification process". This wording edit (a) fractile and mean does not change the capability category hazard curves for requirements of this SR.

each ground motion parameter considered in the probabilistic seismic hazard analysis (b) fractile and mean uniform hazard response spectrum ASME/ANS <not printed here; not CALCULATE the <not printed here; not RA-Sb- focus of this following results as a focus of this 2013 assessment> part of the hazard assessment>

quantification process, compatible with needs for the level of analysis determined in Requirement HLR-SHA-A:

HLR-SHA-G:

Addendum A: For further use in the seismic PRA, the spectral shape shall be based on a site-specific evaluation taking into account the E-12

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III contributions of deaggregated magnitude-distance results of the probabilistic seismic hazard analysis. Broad-band, smooth spectral shapes, such as those presented in NUREG/CR-0098 [5-5] (for lower seismicity sites such as most of those east of the U.S. Rocky Mountains) are also acceptable if they are shown to be appropriate for the site. The use of existing uniform hazard response spectra (UHSs) is acceptable unless evidence comes to light that would challenge these uniform hazard spectral shapes.

Reg Guide 1.200 Rev2 Clarification: For further use in the seismic PRA, the spectral shape shall be based on a site-specific evaluation taking into account the contributions of deaggregated magnitude-distance results of the probabilistic seismic hazard analysis. Broad-band, smooth spectral shapes, ... that would challenge these uniform hazard spectral shapes.

Addendum B: For further use in the seismic PRA, the spectral shape shall be based on a site-specific evaluation taking into account results of the probabilistic seismic hazard analysis.

SHA-G1 ASME/ANS <not printed here; not BASE the response <not printed here; not Addendum B Assessment Equates to RA-Sa- focus of this spectral shape used focus of this Addendum A 2009 assessment> in the seismic PRA assessment>

on site-specific Addendum B deleted the last sentence of this evaluations SR to make the language more concise and performed for the remove redundancy. In addition, Addendum probabilistic B changed the action verb to be consistent seismic hazard with accepted verb usage across SRs. This analysis. REFLECT wording edit does not change the capability or BOUND the site- category requirements of this SR.

specific considerations.

ASME/ANS <not printed here; not ENSURE that the <not printed here; not RA-Sb- focus of this spectral shape used focus of this 2013 assessment> in the seismic PRA assessment>

uses site-specific evaluations performed for the PSHA.

HLR-SHA-H: When use is made of an existing study for probabilistic seismic hazard analysis purposes, it shall be confirmed that the basic data and interpretations are still valid in light of established current information [Addendum A only: the study meets the requirements outlined in A through G above, and the study is suitable for the intended application.]

Reg Guide 1.200 Rev 2 Clarification: When use ... for the intended application. It shall be confirmed that basic data and interpretations E-13

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III from an existing study are valid.

SHA-H1 ASME/ANS <not printed here; not Use of existing <not printed here; not Addendum B Assessment Envelopes RA-Sa- focus of this studies allowed. focus of this Addendum A 2009 assessment> assessment>

ASME/ANS CONFIRM that the basic data and interpretations for any existing Addendum B added additional clarifications RA-Sb- studies used remain valid in light of established current and requirements into the text of this SR. The 2013 information, consistent with the Requirements HLR-SHA-A Addendum B SR wording envelopes that of through HLR-SHA-G, and DESCRIBE the bases and methodology Addendum A.

used.

HLR-SHA-I: A screening analysis shall be performed to assess whether, in addition to the vibratory ground motion, other seismic hazards, such as fault displacement, landslide, soil liquefaction, or soil settlement, need to be included in the seismic PRA [Addendum A only: for the specific application. If so, the seismic PRA shall address the effect of these hazards through assessment of the frequency of hazard occurrence or the magnitude of hazard consequences, or both.]

Reg Guide 1.200 Rev 2 Clarification: A screening analysis ... or the magnitude of hazard consequences, or both. The hazard analysis shall include hazards other than vibratory ground motion if necessary.

SHA-I1 ASME/ANS (There are no supporting requirements here.) Addendum B Assessment Envelopes RA-Sa- Addendum A 2009 ASME/ANS DOCUMENT the bases and methodology used for any screening There are no supporting requirements for RA-Sb- out of the seismic hazards other than vibratory ground motion. HLR-SHA-I in Addendum A. Since the HLRs 2013 only say do something and the SRs establish what needs to be done, the addition of SRs in Addendum B establishes new requirements beyond Addendum A.

SHA-I2 ASME/ANS no SHA-I2 in Addendum A Addendum B Assessment Envelopes RA-Sa- Addendum A 2009 ASME/ANS For those hazards not screened out, INCLUDE their effect There are no supporting requirements for RA-Sb- through assessment of the frequency of hazard occurrence and HLR-SHA-I in Addendum A. Since the HLRs 2013 the magnitude of hazard consequences. only say do something and the SRs establish what needs to be done, the addition of SRs in Addendum B establishes new E-14

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 1: Comparison of Supporting Requirements of Addendum A and Addendum B for SHA Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III requirements beyond Addendum A.

HLR-SHA-J: Documentation of the probabilistic seismic hazard analysis shall be consistent with the applicable supporting requirements SHA-J1 ASME/ANS DOCUMENT the probabilistic seismic hazard analysis in a manner Addendum B Assessment Equates to RA-Sa- that facilitates PRA applications, upgrades, and peer review. Addendum A 2009 ASME/ANS Identical to Addendum A The wording for this SR is the same for RA-Sb- Addendum A and Addendum B.

2013 SHA-J2 ASME/ANS DOCUMENT the process used in the probabilistic seismic hazard Addendum B Assessment Equates to RA-Sa- analysis. For example, this documentation is typically consistent with Addendum A 2009 reference [5-28] and includes a description of:

(a) the specific methods used for source characterization and ground The wording for this SR is the same for motion characterization, Addendum A and Addendum B.

(b) the scientific interpretations that are the basis for the inputs and results, and (c) if an existing PSHA is used, documentation to ensure that it is adequate to meet the spirit of the requirements herein.

ASME/ANS Identical to Addendum A RA-Sb-2013 SHA-J3 ASME/ANS DOCUMENT the sources of model uncertainty and related Addendum B Assessment Equates to RA-Sa- assumptions associated with the probabilistic seismic hazard analysis. Addendum A 2009 ASME/ANS Identical to Addendum A The wording for this SR is the same for RA-Sb- Addendum A and Addendum B.

2013 E-15

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III HLR-SFR-A:

Addendum A: The seismic-fragility evaluation shall be performed to estimate seismic fragilities of SSCs whose failure may contribute to core damage or large early release, or both.

Addendum B: The seismic-fragility evaluation shall be performed to estimate plant-specific, realistic seismic fragilities of structures, or systems, or components, or a combination thereof whose failure may contribute to core damage or large early release, or both.

SFR-A1 ASME/ANS DEVELOP seismic fragilities for all those structures, systems, or Addendum B Assessment Equates to RA-Sa- components, or a combination thereof identified by the systems Addendum A 2009 analysis (see Requirement SPR-D1).

ASME/ANS CALCULATE seismic fragilities for SSCs identified by the systems The changes from Addendum A to RA-Sb- analysis (see Requirement SPR-D1). Addendum B for this SR included the 2013 replacement of "DEVELOP" with "CALCULATE." The change implements a more precise action verb. These wording edits do not change capability category requirements of this SR. The elimination of the phrase a combination thereof does not change the requirements, since it is redundant to other SRs requiring consideration of seismic correlation.

SFR-A2 ASME/ANS <not printed here; not BASE the seismic <not printed here; not Addendum B Assessment Equates to RA-Sa- focus of this fragilities on plant- focus of this Addendum A 2009 assessment> specific data, and assessment>

ENSURE that they The changes from Addendum A to are realistic (median Addendum B involve the replacement of with uncertainties). "BASE" with the more precise action verb Generic data (e.g., "CALCULATE" and the replacement of fragility test data, "conservative" with "applicable" in the last generic seismic sentence with respect to the use of generic qualification test data, fragility data. The latter change precludes and earthquake confusion due to a contradiction, as the experience data) requirement states first that realistic fragilities E-16

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III MAY be used for are required but then the use of generic data screening of certain is to be conservative. In the context of the structures, systems, requirement, the use of "applicable" is correct or components, or a and does not change the capability category combination thereof requirements of this SR.

and for calculating their seismic fragilities by applying the requirements under (HLR-SFR-F),

which permits use of such generic data under specified conditions. However, DEMONSTRATE that any use of such generic data is conservative.

ASME/ANS <not printed here; not CALCULATE the <not printed here; not RA-Sb- focus of this seismic fragilities focus of this 2013 assessment> based on plant- assessment>

specific data, and ENSURE that they are realistic (median with uncertainties).

Generic data (e.g.,

fragility test data, generic seismic qualification test data, and earthquake experience data) may be used for screening E-17

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III of certain SSCs and for calculating their seismic fragilities by applying the Requirement HLR-SFR-F, which permits use of such generic data under specified conditions. However, DEMONSTRATE that any use of such generic data is applicable.

HLR-SFR-B: If screening of high-seismic-capacity components is performed, the basis for the screening shall be fully described.

SFR-B1 ASME/ANS If screening of high-seismic-capacity <not printed here; not Addendum B Assessment Equates to RA-Sa- components is performed, DESCRIBE fully focus of this Addendum A 2009 the basis for screening and supporting assessment>

documents. For example, it is acceptable to Addendum B removes the sentence citing apply guidance given in EPRI NP-6041-SL, NP-6041-SL and NUREG/CR-4334 as Rev. 1, and NUREG/CR-4334 to screen out examples of screening bases and replaces components with high seismic capacity. the action verb "CHOOSE" with the more However, CHOOSE the screening level high precise verb "SELECT." These wording edits enough that the contribution to core damage are non-substantive and do not change frequency and large early release frequency capability category requirements of this SR.

from the screened-out components is not significant.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III ASME/ANS If screening of high-seismic-capacity <not printed here; not RA-Sb- components is performed, DESCRIBE the focus of this 2013 basis for screening and the supporting assessment>

documents and SELECT the screening level high enough that the contribution to core damage frequency and large early release frequency from the screened-out components is not significant.

SFR-B2 ASME/ANS ASSESS and DOCUMENT the applicability of the screening Addendum B Assessment Equates to RA-Sa- criteria given in EPRI NP-6041-SL, Rev. 1 [5-3] and NUREG/CR- Addendum A 2009 4334 [5-4] for the specific plant and specific equipment.

Addendum B deleted this SR. The clarifying ASME/ANS No SFR-B2 in Addendum B non-mandatory footnote for SFR-B1, which RA-Sb- remains unchanged from Addendum A to 2013 Addendum B, reiterates that NP-6041-SL and NUREG/CR-4334 "may be used" and are not mandatory. SFR-B2 in Addendum A states the applicability of NP-6041-SL and NUREG/CR-4334 shall be assessed and documented. However, if NP-6041-SL and NUREG/CR-4334 are applied for screening, SFR-B1 in both Addendum A and Addendum B state that the basis for use shall be described and documentation is addressed under SFR-G2. Therefore, SFR-B2 is redundant and its removal does not change the requirements of the standard.

HLR-SFR-C: The seismic-fragility evaluation shall be based on seismic response that the SSCs experience at their failure levels E-19

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III SFR-C1 ASME/ANS ESTIMATE the seismic responses that the <not printed here; not Addendum B Assessment Envelopes RA-Sa- components experience at their failure levels focus of this Addendum A 2009 on a realistic basis using site-specific assessment>

earthquake response spectra in three The two changes from Addendum A to orthogonal directions, anchored to a ground Addendum B involve the deletion of "site-motion parameter such as peak ground specific" prior to "earthquake response acceleration or average spectral acceleration spectra" in the first sentence and deletion of over a given frequency band. ENSURE that "reflects" in the last sentence. Removal of the spectral shape used reflects or bounds "site-specific" prior to earthquake response the site-specific conditions. spectra is inconsequential as bounding by ASME/ANS ESTIMATE the seismic responses that the <not printed here; not site-specific conditions by definition renders RA-Sb- components experience at their failure levels focus of this the earthquake response spectra site-2013 using input earthquake response spectra in assessment> specific. Removal of "reflects" renders three orthogonal directions, anchored to a Addendum B as more precise since the ground motion parameter such as peak properties must "bound" site-specific ground acceleration or average spectral conditions and not merely "reflect."

acceleration over a given frequency band, and ENSURE that the spectral shape used bounds the site-specific conditions.

SFR-C2 ASME/ANS If probabilistic response analysis is performed <not printed here; not Addendum B Assessment Envelopes RA-Sa- to obtain realistic structural loads and floor focus of this Addendum A 2009 response spectra, ENSURE that the number assessment>

of simulations done (e.g., Monte Carlo The changes from Addendum A to simulation and Latin Hypercube Sampling) is Addendum B are to implement the approved large enough to obtain stable median and action verb "ACCOUNT" to the more precise 85% nonexceedance responses. ACCOUNT verb "INCLUDE" and to eliminate "realistic" in for the entire spectrum of input ground motion the first sentence prior to "structural loads levels displayed in the seismic hazard curves. and floor response spectra." The qualifier E-20

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III ASME/ANS If probabilistic response analysis is performed <not printed here; not realistic is removed to avoid confusion as it is RA-Sb- to obtain structural loads and floor response focus of this unnecessary in the context of applying 2013 spectra, ENSURE that the number of assessment> probabilistic response analysis to determine simulations done (e.g., Monte Carlo structural loads and response spectra.

simulation and Latin Hypercube Sampling) is large enough to obtain stable median and 85% nonexceedance responses. INCLUDE the entire spectrum of input ground motion levels displayed in the seismic hazard curves.

SFR-C3 ASME/ANS If scaling of existing design response analysis <not printed here; not Vogtle Conforms to Addendum A RA-Sa- is used, JUSTIFY it based on the adequacy of focus of this 2009 structural models, foundation characteristics, assessment> The change from Addendum A to Addendum and similarity of input ground motion. B involved the deletion of the word "design" ASME/ANS If scaling of existing response analysis is <not printed here; not from "existing design response analysis."

RA-Sb- used, JUSTIFY it based on the adequacy of focus of this However, Plant Vogtle did not perform scaling 2013 structural models, foundation characteristics, assessment> of any existing response analysis, and and similarity of input ground motion. therefore the change is irrelevant and Vogtle conforms to Addendum A.

SFR-C4 ASME/ANS When the design response analysis models <not printed here; not Addendum B Assessment Equates to RA-Sa- are judged not to be realistic and state of the focus of this Addendum A 2009 art, or when the design input ground motion is assessment>

significantly different from the site-specific Similar to SFR-C3, Addendum B in SFR-C4 input motion, PERFORM new analysis to eliminates "design" from "existing design obtain realistic structural loads and floor response analysis" in the first sentence and response spectra. adds the "for use in the seismic PRA" to the ASME/ANS When the existing response analysis models <not printed here; not last sentence. The judgement of existing RA-Sb- are judged not to be realistic and state of the focus of this response analysis models as unrealistic and 2013 art, or when the design input ground motion is assessment> not state of the art as stated in Addendum B significantly different from the site-specific would include the judgement of existing input motion, PERFORM new analysis to design response analyses; therefore this obtain realistic structural loads and floor change is non-substantive. The addition of response spectra for use in the seismic PRA. "for use in the seismic PRA" is for clarification E-21

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III and also non-substantive.

SFR-C5 ASME/ANS If median-centered response analysis is <not printed here; not Addendum B Assessment Equates to RA-Sa- performed, ESTIMATE the median response focus of this Addendum A 2009 (i.e., structural loads and floor response assessment>

spectra) and variability in the response using The wording for this SR is the same for established methods. Addendum A and Addendum B.

ASME/ANS Identical to Addendum A <not printed here; not RA-Sb- focus of this 2013 assessment>

SFR-C6 ASME/ANS When soil-structure interaction (SSI) analysis <not printed here; not Vogtle Conforms to Accepted Current RA-Sa- is conducted, ENSURE that it is median focus of this Practices 2009 centered using median properties, at soil assessment>

strain levels corresponding to the input The changes in SFR-C6 involved the ground motions that dominate the seismically replacement of "ACCOUNT for" with the more induced core damage frequency. ACCOUNT precise action verb "INCLUDE", the non-for the uncertainties in the SSI analysis by substantive replacement of "dominate" with varying the low strain soil shear modulus "contribute most" for PRA standard between the median value times (1 + Cv) consistency, and the removal of how to and the median value divided by (1 + Cv), perform SSI uncertainty analysis.

where Cv is a factor that accounts for uncertainties in the SSI analysis and soil The SSI uncertainty analysis method properties. If adequate soil investigation presented in Addendum A is derived from data are available, ESTABLISH the mean ASCE 4-98 (as indicated by the non-and standard deviation of the low strain mandatory Note 5). Section 3.3.1.7 of ASCE shear modulus for every soil layer. Then 4-98 states that the use of (1 + Cv) to vary ESTABLISH the value of Cv so that it will low strain soil shear moduli is an acceptable cover the mean plus or minus one method in lieu of probabilistic evaluation, standard deviation for every layer. The which Section C.3.3.1.7 further states is the E-22

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III minimum value of Cv is 0-5. When preferred approach.

insufficient data are available to address uncertainties in soil properties, ENSURE Plant Vogtle accounted for uncertainties in that Cv is taken as no less than 1.0. the SSI analysis by applying strain-compatible soil properties derived from probabilistic evaluation via the PSHA. Use of the ASCE 4-98 alternate approach using (1 +

Cv) would render overly conservative and unrealistic response analysis results, which would invalidate other SRs. Therefore, the Addendum B assessment is considered appropriate.

ASME/ANS When soil-structure interaction (SSI) analysis <not printed here; not RA-Sb- is conducted, ENSURE that it is median focus of this 2013 centered using median properties, at soil assessment>

strain levels corresponding to the input ground motions that contribute most to the seismically induced core damage frequency.

INCLUDE the uncertainties in the SSI analysis.

HLR-SFR-D: The seismic-fragility evaluation shall be performed for critical failure modes of SSCs such as structural failure modes and functional failure modes identified through the review of plant design documents, supplemented as needed by earthquake experience data, fragility test data, generic qualification test data, and a walkdown.

SFR-D1 ASME/ANS IDENTIFY realistic failure modes of structures and equipment that Addendum B Assessment Envelopes RA-Sa- interfere with the operability of equipment during or after the Addendum A 2009 earthquake through a review of the plant design documents and the walkdown. The change from Addendum A to Addendum E-23

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III ASME/ANS IDENTIFY realistic failure modes of structures ( e.g., sliding, B involved the move of example failure RA-Sb- overturning, yielding, and excessive drift), equipment (e.g., modes from SFR-D2 to SFR-D1.

2013 anchorage failure, impact with adjacent equipment or structures, bracing failure, and functional failure), and soil (e.g., liquefaction, slope instability, and excessive differential settlement) that interfere with the operability of equipment during or after the earthquake, through a review of the plant design documents and the walkdown.

SFR-D2 ASME/ANS EXAMINE all relevant failure modes of structures (e.g., sliding, Addendum B Assessment Envelopes RA-Sa- overturning, yielding, and excessive drift), equipment (e.g., Addendum A 2009 anchorage failure, impact with adjacent equipment or structures, bracing failure, and functional failure), and soil (i.e., liquefaction, The changes from Addendum A to slope instability, and excessive differential settlement), and Addendum B for this SR involved the EVALUATE fragilities for critical failure modes. aforementioned move of example failure ASME/ANS EVALUATE all relevant failure modes identified in Requirement modes to SFR-D1 and change in wording RA-Sb- SFR-D1, and EVALUATE fragilities for critical failure modes. from "EXAMINE all relevant failure modes of 2013 structures..." to "EVALUATE relevant failure modes identified in SFR-D1." The latter change implements a more precise action verb in addition to providing more specificity for the evaluation of failure modes.

HLR-SFR-E: The seismic-fragility evaluation shall incorporate the findings of a detailed walkdown of the plant focusing on the anchorage, lateral seismic support, and potential systems interactions.

SFR-E1 ASME/ANS CONDUCT a detailed walkdown of the plant, focusing on equipment Addendum B Assessment Equates to RA-Sa- anchorage, lateral seismic support, spatial interactions, and potential Addendum A 2009 systems interactions (both structural and functional interactions).

The wording for this SR is the same for ASME/ANS Identical to Addendum A Addendum A and Addendum B.

RA-Sb-2013 E-24

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III SFR-E2 ASME/ANS DOCUMENT the walkdown procedures, walkdown team composition Addendum B Assessment Equates to RA-Sa- and its members qualifications, walkdown observations, and Addendum A 2009 conclusions.

ASME/ANS Identical to Addendum A The wording for this SR is the same for RA-Sb- Addendum A and Addendum B.

2013 SFR-E3 ASME/ANS If components are screened out during or following the walkdown, Addendum B Assessment Envelopes RA-Sa- DOCUMENT anchorage calculations and PROVIDE the basis Addendum A 2009 justifying such a screening.

The change implemented from Addendum A ASME/ANS If components are screened out during or following the walkdown, to Addendum B involves increased RA-Sb- DOCUMENT the basis, including any anchorage calculations that requirement to not only document anchorage 2013 justify such a screening. screening but all screening (e.g. including functional or component structure).

SFR-E4 ASME/ANS During the walkdown, FOCUS on the potential for seismically induced Addendum B Assessment Envelopes RA-Sa- fire and flooding. Addendum A 2009 ASME/ANS During the walkdown, EVALUATE the potential for seismically The change from Addendum A to Addendum RA-Sb- induced fire and flooding by focusing on the issues described in B involved changing "FOCUS" into the more 2013 NUREG-1407 [5-7]. precise action verb "EVALUATE" in addition to adding specific criteria pertaining to NUREG-1407.

SFR-E5 ASME/ANS During the walkdown, EXAMINE potential sources of interaction (e.g., Addendum B Assessment Equates to RA-Sa- II/I issues, impact between cabinets, masonry walls, flammable and Addendum A 2009 combustion sources, flooding, and spray) and consequences of such interactions on equipment contained in the systems model. The change from Addendum A to Addendum B for this SR involved the replacement of ASME/ANS During the walkdown, EVALUATE potential sources of interaction "EXAMINE" with "EVALUATE." The action RA-Sb- (e.g., II/I issues, impact between cabinets, masonry walls, flammable verb change was made to be consistent with 2013 and combustion sources, flooding, and spray) and consequences of accepted verb usage across SRs. These such interactions on equipment contained in the systems model.

wording edits do not change capability category requirements of this SR..

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III HLR-SFR-F: The calculation of seismic-fragility parameters such as median capacity and variabilities shall be based on plant-specific data or, if necessary, on earthquake experience data, fragility test data, and generic qualification test data. Use of such generic data shall be justified.

SFR-F1 ASME/ANS BASE component seismic-fragility parameters <not printed here; not Addendum B Assessment Envelopes RA-Sa- such as median capacity and variabilities focus of this Addendum A 2009 (logarithmic standard deviations reflecting assessment>

randomness and uncertainty) on plant-specific Addendum B changes the action verb from data supplemented as appropriate by "BASE" to the more precise and restrictive earthquake experience data, fragility test verb "CALCULATE" in keeping with the data, and generic qualification test data. approved action verb list and adds more specificity to the use of sources beyond plant-ASME/ANS CALCULATE component seismic-fragility <not printed here; not specific data, including the provision to justify RA-Sb- parameters such as median capacity and focus of this the appropriateness of generic fragility data.

2013 variabilities (logarithmic standard deviations assessment>

reflecting randomness and uncertainty) based on plant-specific data or, if necessary, on earthquake experience data, fragility test data, and generic qualification test data.

Exception: JUSTIFY the use of generic fragility for any SSC as being appropriate for the plant.

SFR-F2 ASME/ANS For all structures, or systems, or components, <not printed here; not Addendum B Assessment Equates to RA-Sa- or a combination thereof (SSCs) that appear focus of this Addendum A 2009 in the dominant accident cut sets, ENSURE assessment>

that they have site-specific fragility Addendum B changes the use of "dominant parameters that are derived based on plant- accident cut sets" in Addendum A to specific information, such as anchoring and "significant accident sequences." This installation of the component or structure and wording edit is for consistency with the plant-specific material test data. Exception: convention used elsewhere in the PRA JUSTIFY the use of generic fragility for any standard to be software neutral and does SSC as being appropriate for the plant. not change the capability category E-26

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III ASME/ANS For all SSCs that appear in the significant <not printed here; not requirements of this SR.

RA-Sb- accident sequences, ENSURE that they have focus of this 2013 site-specific fragility parameters that are assessment>

derived based on plant-specific information, such as anchoring and installation of the component or structure and plant-specific material test data. Exception: JUSTIFY the use of generic fragility for any SSC as being appropriate for the plant.

SFR-F3 ASME/ANS <not printed here; not DEVELOP seismic fragilities for relays Addendum B Assessment Equates to RA-Sa- focus of this identified to be essential and that are included Addendum A 2009 assessment> in the systems-analysis model.

The change from Addendum A to Addendum ASME/ANS <not printed here; not CALCULATE seismic fragilities for relays B for this SR was the replacement of RA-Sb- focus of this identified to be essential and that are included "DEVELOP" with "CALCULATE." The action 2013 assessment> in the systems-analysis model. verb change was made to be consistent with accepted verb usage across SRs. These wording edits do not change capability category requirements of this SR.

SFR-F4 ASME/ANS DEVELOP seismic fragilities for structures, or systems, or Addendum B Assessment Equates to RA-Sa- components, or a combination thereof that are identified in the Addendum A 2009 systems model as playing a role in the large early release frequency part of the seismic PRA. (See Requirements SPR-A1 and SPR-A3.) The changes from Addendum A to ASME/ANS CALCULATE seismic fragilities for SSCs that are identified in the Addendum B for this SR included the RA-Sb- systems model as playing a role in the large early release frequency replacement of "DEVELOP" with 2013 part of the seismic PRA. (See Requirements SPR-A1 and SPR-A3.) "CALCULATE." The action verb change was made to be consistent with accepted verb usage across SRs. Also, SSC abbreviation used instead. These wording edits do not change capability category requirements of this SR.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III HLR-SFR-G: Documentation of the seismic-fragility evaluation shall be consistent with the applicable supporting requirements.

SFR-G1 ASME/ANS DOCUMENT the seismic fragility analysis in a manner that facilitates Addendum B Assessment Equates to RA-Sa- PRA applications, upgrades, and peer review. Addendum A 2009 ASME/ANS Identical to Addendum A The wording for this SR is the same for RA-Sb- Addendum A and Addendum B.

2013 SFR-G2 ASME/ANS DOCUMENT the process used in the seismic-fragility analysis. For Addendum B Assessment Equates to RA-Sa- example, this typically includes a description of Addendum A 2009 (a) The methodologies used to quantify the seismic fragilities of structures, or systems, or components, or a combination thereof, The only change in this SR is related to use together with key assumptions of "structures, systems, and components" (b) The seismic fragilities of structures, or systems, or components, versus its acronym "SSC." This change is or a combination thereof (SSC) fragility values that includes the considered editorial and does not change the method of seismic qualification, the dominant failure mode(s), the capability category requirements of this SR.

source of information, and the location of the component (c) The fragility parameter values (i.e., median acceleration capacity, Br and Bu) and the technical bases for them for each analyzed SSC, and (d) the different elements of seismic-fragility analysis, such as (1) the seismic response analysis (2) the screening steps (3) the walkdown (4) the review of design documents (5) the identification of critical failure modes for each SSC, and (6) the calculation of fragility parameter values for each SSC modeled E-28

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 2: Comparison of Supporting Requirements of Addendum A and Addendum B for SFR Standard Capability Category Capability Category Capability Category SR Basis for Assessment (CC-II Focus)

Rev. I II III ASME/ANS DOCUMENT the process used in the seismic-fragility analysis. For RA-Sb- example, this typically includes a description of 2013 (a) the methodologies used to quantify the seismic fragilities of SSCs, together with key assumptions (b) the SSC fragility values that includes the method of seismic qualification, the dominant failure mode(s), the source of information, and the location of the component (c) the fragility parameter values (i.e., median acceleration capacity, Br and Bu) and the technical bases for them for each analyzed SSC, and (d) the different elements of seismic-fragility analysis, such as (1) the seismic response analysis (2) the screening steps (3) the walkdown (4) the review of design documents (5) the identification of critical failure modes for each SSC, and (6) the calculation of fragility parameter values for each SSC modeled SFR-G3 ASME/ANS DOCUMENT the sources of model uncertainty and related Vogtle Conforms to Addendum A RA-Sa- assumptions associated with the seismic fragility analysis.

2009 Addendum B deleted this SR. However, the Plant Vogtle 1&2 SPRA documentation ASME/ANS Deleted. describes in detail the sources of model RA-Sb- uncertainty and related assumptions 2013 associated with the seismic fragility analysis.

Therefore, the Vogtle SPRA conforms to Addendum A.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III HLR-SPR-A: The seismic-PRA systems model shall include seismic-caused initiating events and other failures including seismic-induced SSC failures, non-seismic-induced unavailabilities, and human errors, that give rise to significant accident sequences and/or significant accident progression sequences.

SPR-A1 ASME/ANS ENSURE that earthquake-caused initiating events that give rise to Addendum B Assessment Equates to RA-Sa- significant accident sequences and/or significant accident progression Addendum A 2009 sequences are included in the seismic-PRA system model using a systematic process. The wording for this SR is the same for Addendum A and Addendum B. A minor ASME/ANS Identical to Addendum A clarification (i.e., very low magnitude RA-Sb- earthquakes can be excluded from the 2013 quantification process) was added in Addendum B to the clarifying non-mandatory footnote for this SR; this footnote adjustment does not change the capability category requirements of this SR.

SPR-A2 ASME/ANS In the initiating-event selection process, DEVELOP a hierarchy to Addendum B Assessment Equates to RA-Sa- ensure that every earthquake greater than a certain defined size Addendum A 2009 produces a plant shutdown within the systems model.

ASME/ANS Identical to Addendum A The wording for this SR is the same for RA-Sb- Addendum A and Addendum B. A minor 2013 clarification (i.e., event ordering by consequence severity) was added in Addendum B to the clarifying non-mandatory footnote for this SR; this footnote adjustment does not change the capability category requirements of this SR.

SPR-A3 ASME/ANS USE the event trees and fault trees from the internal-event at-power Addendum B Assessment Equates to RA-Sa- PRA model as the basis for the seismic event trees. Addendum A 2009 E-30

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III ASME/ANS USE the accident sequences and the systems logic model from Some of the terms in this SR were changed RA-Sb- the at-power, internal-event PRA model as the basis for the seismic- in Addendum B so that they would not be less 2013 PRA model. specific to a certain type of PRA modeling software. These term clarifications do not change the capability category requirements of this SR.

SPR-A4 ASME/ANS This supporting requirement is new to Addendum B and not Addendum B Assessment Equates to (Add. B) RA-Sb- included in Addendum A. Addendum A 2013 Under special circumstances based on the judgment of the analyst, DEVELOP an ad hoc systems model tailored especially to the Addendum B added this SR to recognize that seismic-PRA configurations or issues being modeled, instead of some utilities may build a separate stand-starting with the internal-events model and adapting it, as in alone SPRA as opposed to adding seismic Requirement SPR-A3. If this approach is used, ENSURE that the aspects into an existing internal events PRA resulting model is consistent with the internal-events systems model (as described by SPR-A3). This new SR regarding plant response and the cause-effect relationships of the ensures that the technical capability of the failures. base modeling would be consistent with the internal events technical capability requirements. For Vogtle, this specific SR is not applicable because the Vogtle 1&2 SPRA is built upon the internal events PRA per SR SPR-A3 and thus the Vogtle SPRA conforms to Addendum A.

SPR-A4 ASME/ANS SPR-A4 of Addendum A: Addendum B Assessment Equates to (Add. A) RA-Sa- ENSURE that the PRA systems models reflect earthquake-caused Addendum A SPR-A5 2009 failures and nonseismically induced unavailabilities and human errors (Add. B) that give rise to significant accident sequences or significant accident The wording for this SR is the same for progression sequences. Addendum A and Addendum B.

ASME/ANS SPR-A5 of Addendum B is identical to SPR-A4 of Addendum A. Miscellaneous edits were made in Addendum RA-Sb- There is no change in the supporting requirement from B to the clarifying non-mandatory footnote for 2013 Addendum A to Addendum B, except that the insertion of a new this SR; this footnote adjustment does not SPR-A4 in Addendum B changes the number for this change the capability category requirements E-31

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III requirement. of this SR.

HLR-SPR-B: The seismic-PRA systems model shall be adapted to incorporate seismic-analysis aspects that are different from corresponding aspects found in the at-power, internal-events PRA systems model.

SPR-B1 ASME/ANS In each of the following aspects of the seismic-PRA systems-analysis Vogtle Conforms to Addendum A RA-Sa- work, SATISFY the corresponding requirements in Part 2, except 2009 where they are not applicable or where this Part includes additional Addendum B removed the last sentence of requirements. DEVELOP a defined basis to support the claimed this SR in response to an EPRI 2011 nonapplicability of any exceptions. The aspects governed by this comment on the Addendum B ballot. The last requirement are sentence was removed in Addendum B (a) initiating-event analysis because it was determined to be confusing as (b) accident-sequence analysis wells as inappropriate specificity to require all (c) success-criteria analysis new aspects in the SPRA to meet the exact (d) systems analysis same CCs of Part 2 SRs. In addition, (e) data analysis Addendum B changed the action verb to be (f) human-reliability analysis consistent with accepted verb usage across (g) use of expert judgment SRs. The Addendum B SR requirement When the Part 2 requirements are used, FOLLOW the Capability clarifications are appropriate. Regardless, Category designations in Part 2, and for consistency USE the the Plant Vogtle 1&2 SPRA builds upon the same Capability Category in this analysis. internal events PRA and uses the same E-32

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III ASME/ANS In each of the following aspects of the seismic-PRA systems-analysis general methodologies as used for Part 2 RA-Sb- work, SATISFY the corresponding requirements in Part 2, except where applicable; therefore, the Vogtle SPRA 2013 where they are not applicable or where this Part includes additional conforms to Addendum A.

requirements. SPECIFY a basis to support the claimed nonapplicability of any exceptions. The aspects governed by this requirement are (a) initiating-event analysis (b) accident-sequence analysis (c) success-criteria analysis (d) systems analysis (e) data analysis (f) human-reliability analysis (g) use of expert judgment SPR-B2 ASME/ANS In the human reliability analysis (HRA) aspect, EXAMINE Addendum B Assessment Envelopes RA-Sa- additional post earthquake stresses that can increase the Addendum A 2009 likelihood of human errors or inattention, compared to the likelihood assigned in the internal-events HRA when the same In response to an EPRI 2011 comment on the activities are undertaken in no earthquake accident sequences. Addendum B ballot, Addendum B added CCI-Whether or not increases in error probabilities are used, JUSTIFY II and CCIII capability differentiation as well the basis for this decision about what error rates to use. as the requirement to include the seismic ASME/ANS INCLUDE the following seismic impacts on <not printed here; HEP impacts on the internal events based RA-Sb- performance-shaping factors (PSFs) for the not focus of this HEPs, not simply to Examine them. It also 2013 control room and ex-control room post- assessment> expanded on the considerations to initiator actions as appropriate to the emphasize PSFs beyond just stress. The human reliability analysis (HRA) Addendum B SR wording envelopes that of methodology used: Addendum A.

(a) additional post-earthquake workload and stress that can increase the likelihood of human errors or inattention E-33

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III (b) seismic failures that impact access (c) cue availability SPR-B3 ASME/ANS SPR-B3 of Addendum A: Addendum B Assessment Equates to (Add. A) RA-Sa- If any screening is performed, PERFORM it using defined criteria Addendum A SPR- 2009 that are documented in the PRA.

B4a Addendum B changed the sentence structure ASME/ANS SPR-B4a of Addendum B:

(Add. B) to correct awkward wording and to use RA-Sb- If screening out on the basis of seismic capacity is performed in accepted verb. This wording edit does not 2013 the systems model, SPECIFY the screening criterion.

change the capability category requirements of this SR.

SPR-B4 ASME/ANS SPR-B4 of Addendum A: <not printed here; Addendum B Assessment Equates to (Add. A) RA-Sa- PERFORM an analysis of seismic-caused not focus of this Addendum A SPR-B3 2009 dependencies and correlations in a way so that assessment>

(Add. B) any screening of SSCs appropriately accounts Addendum B deleted the phrase for those dependencies and correlations. "dependencies and" because they are USE bounding or generic correlation values redundant to the "correlation" term so as to and PROVIDE the basis for such use. avoid reviewer potential confusion. This ASME/ANS SPR-B3 of Addendum B: <not printed here; wording edit does not change the capability RA-Sb- PERFORM an analysis of seismic-caused not focus of this category requirements of this SR.

2013 dependencies and correlations in a way so that assessment>

any screening of SSCs appropriately accounts for those correlations.

USE bounding or generic correlation values and PROVIDE the basis for such use.

SPR-B5 ASME/ANS SPR-B5 of Addendum A: Addendum B Assessment Equates to (Add. A) RA-Sa- ENSURE that any screening of human-error basic events and non- Addendum A 2009 seismic-failure basic events does not significantly affect the PRAs results. Addendum B deleted this SR because it is ASME/ANS No SR of Addendum B directly matches with SPR-B5 of redundant to SR SPR-A5, which already RA-Sb- Addendum A requires modeling of operator actions that 2013 contribute to significant accident sequences.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III Also, it is redundant in part to SR SPR-E3, which requires validation that any screening does not impact the results. Finally, Vogtle did not screen out any human-error or non-seismic events that were in the FPIE model and would propagate through seismic accident sequences, and so conforms to Addendum A.

SPR- ASME/ANS Not included in Addendum A. Addendum B Assessment Envelopes B4b RA-Sa- Addendum A 2009 This SR is new for Addendum B to ensure ASME/ANS SPR-B4b of Addendum B: that recoveries added to the SPRA (i.e., not RA-Sb- If post-earthquake recovery actions are included in the systems already included in the internal events PRA) 2013 model, INCLUDE them on a documented basis. are assessed for appropriateness.

Addendum B envelopes Addendum A with respect to this SR.

SPR-B6 ASME/ANS <not printed here; SPR-B6 of Addendum A: Addendum B Assessment Envelopes (Add. A) RA-Sa- not focus of this EXAMINE the effects of the chatter of relays Addendum A SPR-B4 2009 assessment> and similar devices.

(Add. B) In response to an EPRI 2011 comment on the ASME/ANS SPR-B4 of Addendum B: Addendum B ballot, Addendum B added the RA-Sb- INCLUDE the effects of the chatter of relays and similar devices in the requirement to include the effects of relay 2013 systems model. chatter in the model, not simply to examine them. The differentiation for "low ruggedness relays" is deleted in Addendum B because the issue of chatter fragility is addressed in SFR SRs. The Addendum B SR wording envelopes that of Addendum A.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III SPR-B7 ASME/ANS SPR-B7 of Addendum A: Addendum B Assessment Equates to (Add. A) RA-Sa- In the systems-analysis models, for each basic event that represents a Addendum A SPR-B5 2009 seismically caused failure, INCLUDE the complementary success (Add. B) state where applicable to a particular SSC. Addendum B revised the wording of this SR to include a capability category distinction to explicitly model fragility complements for risk significant fragilities for CCI-II and for all modeled fragilities for CCIII. The Vogtle 1&2 SPRA uses the SPRA CAFTA suite of codes ASME/ANS SPR-B5 of Addendum B: <not printed here; with the ACUBE module addressing the RA-Sb- In the systems-analysis models, for each not focus of this fragility complement modeling and so meets 2013 basic event that represents a significant assessment> the intent of both Addenda A and B since the seismically caused failure, INCLUDE the quantification accounts mathematically for the complementary success state where success states.

applicable to a particular SSC, and SPECIFY the criteria used for the term significant in this activity.

SPR-B8 ASME/ANS SPR-B8 of Addendum A: Addendum B Assessment Equates to (Add. A) RA-Sa- EXAMINE the possibility that a large earthquake can cause damage Addendum A SPR-B6 2009 that blocks personnel access to safety equipment or controls, thereby (Add. B) inhibiting operator actions that might otherwise be credited. Addendum B changed the action verb to be ASME/ANS SPR-B6 of Addendum B: consistent with accepted verb usage across RA-Sb- EVALUATE the possibility that a large earthquake can cause damage SRs. This wording edit does not change the 2013 that blocks personnel access to safety equipment or controls, thereby capability category requirements of this SR.

inhibiting operator actions that might otherwise be credited.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III SPR-B9 ASME/ANS <not printed here; SPR-B9 of Addendum A: Addendum B CCII Assessment Equates to (Add. A) RA-Sa- not focus of this EXAMINE the likelihood that system Addendum A CCII-III SPR-B7 2009 assessment> recoveries modeled in the internal-events (Add. B) PRA may be more complex or even not In response to an EPRI 2011 comment on the possible after a large earthquake, and Addendum B ballot, Addendum B added ADJUST the recovery models accordingly. three capability differentiations. CCII requirements are effectively the same for Addendum A and Addendum B. The Addendum B SR adds the clarification that generic and/or conservative recovery values are acceptable. The Addendum B SR CCII ASME/ANS <not printed here; SPR-B7 of Addendum <not printed here; wording effectively equates to Addendum A RA-Sb- not focus of this B: not focus of this CCII-III given the state of practice at the time 2013 assessment> EVALUATE the assessment>

(i.e., detailed plant-specific system recovery likelihood that system probability calculations were not typical recoveries modeled in practice at the time of Addendum A).

the internal-events PRA may be more complex or even not possible after a large earthquake, and ADJUST the recovery models accordingly. It is acceptable to use generic or conservative recovery values.

SPR- ASME/ANS SPR-B10 of Addendum A: Addendum B Assessment Envelopes B10 RA-Sa- EXAMINE the effect of including an earthquake-caused small- Addendum A (Add. A) 2009 small loss-of-coolant accident as an additional fault within each SPR-B8 sequence in the seismic-PRA model. Addendum B added differentiation of E-37

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III (Add. B) ASME/ANS SPR-B8 of Addendum B: <not printed here; capability requirements to this SR that require RA-Sb- ASSUME the existence of an earthquake- not focus of this modeling incorporation into the SPRA (if the 2013 caused very small loss-of-coolant assessment> topic requires it for a specific plant) whereas accident in the seismic-PRA accident the EXAMINE verb in Addendum A did not sequences and system modeling, unless it require incorporation into the SPRA (i.e., it is demonstrated that such a LOCA can be could be done as a sensitivity study). The excluded, based on a walkdown or on Addendum B SR wording envelopes that of another examination of the possible Addendum A.

sources of such a LOCA.

SPR- ASME/ANS SPR-B11 of Addendum A: Addendum B Assessment Envelopes B11 RA-Sa- In the seismic PRA walkdown, INCLUDE the potential for Addendum A (Add. A) 2009 seismically induced fires and flooding following the guidance SPR-B9 given in NUREG-1407. In response to an EPRI 2011 comment on the (Add. B) ASME/ANS SPR-B9 of Addendum B: Addendum B ballot, Addendum B added the RA-Sb- If the seismic PRA walkdown (see Requirement SFR-E4) requirement to include risk significant 2013 identifies the potential for seismically induced fires and flooding, scenarios into the SPRA models as opposed INCLUDE potential significant contributions to accident to only including them in the walkdown.

sequences in the systems model. Reference to NUREG-1407 was removed in Addendum B because this SR refers to SFR-E4 for input and SFR-E4 already includes the reference to NUREG-1407. The Addendum B SR wording envelopes that of Addendum A.

HLR-SPR-C: The seismic-PRA systems model shall reflect the as-built and as-operated plant being analyzed.

SPR-C1 ASME/ANS To ensure that the systems-analysis model reflects the as-built, as- Addendum B Assessment Equates to RA-Sa- operated plant, JUSTIFY any conservatisms or other distortions Addendum A 2009 introduced by demonstrating that the seismic-PRAs validity for applications is maintained. Addendum B changed the last clause of this E-38

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III ASME/ANS To ensure that the systems-analysis model reflects the as-built, as- SR because the wording was awkward. This RA-Sb- operated plant, JUSTIFY any conservatisms or other distortions that wording refinement does not change the 2013 do not adequately reflect the as-built, as-operated plant. capability category requirements of this SR.

HLR-SPR-D: The list of SSCs selected for seismic-fragility analysis shall include the SSCs that participate in accident sequences included in the seismic-PRA systems model.

SPR-D1 ASME/ANS USE the seismic PRA systems model as the basis for developing the Addendum B Assessment Envelopes RA-Sa- seismic equipment list, which is the list of all SSCs to be Addendum A 2009 considered by the subsequent seismic-fragility evaluation task.

ASME/ANS USE the PRA systems model as the basis for developing the seismic Addendum B added additional clarifications RA-Sb- equipment list to support the fragility analysis of 5-2.2. INCLUDE and requirements into the text of this SR.

2013 structures and passive components that may not be present in The Addendum B SR wording envelopes that the internal-events model but that require consideration in the of Addendum A.

seismic PRA. SUPPLEMENT the list based on the review of industry seismic-PRA seismic equipment lists (SELs), if available.

HLR-SPR-E: The analysis to quantify core damage frequency and large early release frequency shall appropriately integrate the seismic hazard, the seismic fragilities, and the systems-analysis aspects SPR-E1 ASME/ANS In the quantification of core damage frequency and large early release Addendum B Assessment Equates to RA-Sa- frequency, PERFORM the integration using the seismic hazard, Addendum A 2009 fragility, and systems analyses.

ASME/ANS Identical to Addendum A The wording for this SR is the same for RA-Sb- Addendum A and Addendum B. Minor edits 2013 were made in Addendum B to the clarifying non-mandatory footnote for this SR; this footnote adjustment does not change the capability category requirements of this SR.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III SPR-E2 ASME/ANS <not printed here; In quantifying core damage frequency and Addendum B Assessment Envelopes RA-Sa- not focus of this large early release frequency, PERFORM the Addendum A 2009 assessment> quantification on a cut-set-by-cut set or accident-sequence-by-accident-sequence Addendum B revised this SR to back-basis (or for defined groups of these), as well reference to Part 2 requirements for the as on a comprehensive/integrated basis. accident sequence quantification. This edit ASME/ANS PERFORM seismic-sequence quantification in accordance with the was made for consistency across the Std RA-Sb- applicable requirements described in 2-2.7. Parts to refer back to Part 2 SRs where 2013 applicable. The wording edit in Addendum B to this SR expands the capability category requirements beyond the requirements of Addendum A by incorporating many more SRs.

SPR-E3 ASME/ANS In the analysis, USE the quantification process to ensure that any Addendum B Assessment Equates to RA-Sa- screening of SSCs does not affect the results, taking into account Addendum A 2009 the various uncertainties.

In addition to minor wording changes, ASME/ANS USE the quantification process to confirm and support the Addendum B revised this SR to remove the RA-Sb- screening of SSCs (refer to Requirement SFR-B1). clause regarding consideration of 2013 uncertainties. The use of the phrase "confirm and support" allows for the analyst to determine the best way to validate the screening, whereas Addendum A went beyond "what to do" into "how to do it." The end result is the same.

SPR-E4 ASME/ANS In the integration/quantification analysis, <not printed here; Addendum B Assessment Equates to RA-Sa- ACCOUNT for all significant dependencies and not focus of this Addendum A 2009 correlations that affect the results. assessment>

It is acceptable to use generic correlation Addendum B changed action verbs to be values. If used, PROVIDE the basis for such consistent with accepted verb usage across E-40

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III use. SRs, and also deleted the redundant "dependencies" term. These wording edits do not change capability category requirements of this SR.

ASME/ANS In the integration/quantification analysis, <not printed here; RA-Sb- INCLUDE the significant correlations that affect not focus of this 2013 the results. assessment>

It is acceptable to use generic correlation values. If used, SPECIFY the basis for such use.

SPR-E5 ASME/ANS <not printed here; Identical to Addendum B CCII except Addendum B CCII Assessment Equates to RA-Sa- not focus of this Addendum A uses ACCOUNT verb. Addendum A CCII-III 2009 assessment>

Addendum B changed action verbs to be ASME/ANS <not printed here; In the <not printed here; consistent with accepted verb usage across RA-Sb- not focus of this integration/quantification not focus of this SRs. Three Capability Category distinctions 2013 assessment> analysis, INCLUDE in assessment>

are instituted for Addendum B (Addendum B the uncertainties in core CCII corresponds to Addendum A CCII-III).

damage frequency and These edits do not change the CCII capability large early release category requirements of this SR.

frequency results that arise from each of the several inputs (the seismic hazard, the seismic fragilities, and the systems-analysis aspects).

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III SPR-E6 ASME/ANS PERFORM appropriate sensitivity studies to illuminate the sensitivity Addendum B Assessment Envelopes (Add. A) RA-Sa- of the core damage frequency and large early release frequency Addendum A 2009 results to the assumptions used about dependencies and correlations.

In response to an EPRI 2011 comment on the ASME/ANS Deleted in Addendum B Addendum B ballot, Addendum B deleted this RA-Sb- SR because performance of sensitivity 2013 studies is already addressed by another SR through the new back-reference to meeting the Part 2 quantification requirements (see SPR-E2), which includes the requirement to conduct appropriate sensitivity studies to address sources of uncertainty. This new back-reference implies requirements well beyond just sensitivity to correlations, and so the Addendum B approach envelopes Addendum A, even with this deletion. The Vogtle 1&2 SPRA documentation includes a sensitivity case related to seismic fragility correlation modeling.

SPR-E6 ASME/ANS New Requirement in Addendum B. Addendum B Assessment Envelopes (Add. B) RA-Sa- Addendum A 2009 ASME/ANS In the analysis of LERF, SATISFY the LERF requirements in 2-2.8, Addendum B added this SR to back-RA-Sb- where applicable. reference to Part 2 requirements for the 2013 Note 6 - Those aspects of LERF analysis that are common to internal- LERF analysis. This new SR was added for events PRA and seismic PRA are referred to here. Also, the consistency across the Std Parts to refer discussion of LERF analysis in the last four paragraphs of 5-1.3 is back to Part 2 SRs where applicable. The E-42

Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III broadly applicable and should be referred to as background Addendum B SR wording envelopes that of information. Addendum A given that Addendum A did not specifically cite this LERF back-referencing to Part 2.

HLR-SPR-F: The seismic-PRA analysis shall be documented in a manner that facilitates applying the PRA and updating it, and that enables peer review.

SPR-F1 ASME/ANS DOCUMENT the seismic plant response analysis and quantification in Addendum B Assessment Equates to RA-Sa- a manner that facilitates PRA applications, upgrades, and peer review. Addendum A 2009 The wording for this SR is the same for Addendum A and Addendum B. Addendum B edited the non-mandatory footnote for this ASME/ANS Identical to Addendum A SR. This footnote edit does not change the RA-Sb- capability category requirements of this SR.

2013 SPR-F2 ASME/ANS DOCUMENT the process used in the seismic plant response analysis Addendum B Assessment Equates to RA-Sa- and quantification. For example, this documentation typically includes Addendum A 2009 a description of:

(a) the specific adaptations made in the internal events PRA model to Addendum B moved the non-mandatory list produce the seismic-PRA model, and their motivation, and of examples to the associated non-mandatory (b) the major outputs of a seismic PRA, such as mean core damage footnote. This edit does not change the frequency (CDF), mean large early release frequency (LERF), capability category requirements of this SR.

uncertainty distributions on CDF and LERF, results of sensitivity studies, significant risk contributors, and so on, are examples of the PRA results that are generally documented.

ASME/ANS DOCUMENT the process used in the seismic plant response analysis RA-Sb- and quantification.

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Enclosure to NL-17-1201 SNC Response to NRC Request Regarding Risk-Informed Methodology Table 3: Comparison of Supporting Requirements of Addendum A and Addendum B for SPR Standard Capability Capability SR Capability Category II Basis for Assessment (CC-II Focus)

Rev. Category I Category III SPR-F3 ASME/ANS DOCUMENT the sources of model uncertainty and related Addendum B Assessment Equates to RA-Sa- assumptions associated with the seismic plant response model Addendum A 2009 development.

The wording for this SR is the same for Addendum A and Addendum B. Addendum ASME/ANS Identical to Addendum A.

A had a missing non-mandatory footnote (not RA-Sb-all uncertainties need to be assigned a 2013 numerical distribution in the documentation) that was re-inserted in Addendum B. This footnote does not change the capability category requirements of this SR.

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