ML18087A372

3/14/2018 - Regulatory Information Conference (RIC) 2018 - Session TH35 - Driver Slides - Closure of PRA Peer Review Facts and Observations

ML18087A372
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Issue date:	03/14/2018
From:	Office of Nuclear Reactor Regulation
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Closure of PRA Peer Review Facts and ObservationsRegulatory Information ConferenceTechnical Session TH35Adrienne Driver, Reliability and Risk Analyst March 14, 2018

Background:

New Process for closure of F&Os Industry Guidance and ProcessesPRA Processes for Regulatory ReviewOverview of Appendix X: Closure of F&Os ProcessIndustry Pilots and Staff ObservationsStaff Acceptance of Appendix XPost Acceptance ObservationsNRC Audits: Crediting F&O ClosureProposed Staff Endorsement in RG 1.200, Revision 3

Background:

The Risk Informed Steering Committee (RISC) identified several high-priority issues to foster an environment conducive to achieving the full benefit of risk-informed regulation.-Common theme was difficulty associated with evaluation of Probabilistic Risk Assessment (PRA) technical acceptability in review of risk-informed licensing applications

• Working Group 1 Issue 2 Objective: Improve process for documentation and closure of Peer Review Facts and Observations (F&Os)

ASME/ANS PRA Standard

• Provides standards for peer review of a PRA to be used in risk-informed decisions for commercial nuclear power plants.

• Defines PRA upgrades and stipulates when a peer review should be performed.

• Peer Review

• Inherently establishes PRA model-of-record (MOR)

NEI 05-04/07-12/12-16

• Guidance for Peer Review Process-Assessment of the Capability Category (CC) of the Supporting Requirements (SR), CC-I, CC-II, CC-III

• Full Scope

• Focused Scope

• Gap Assessment to RG 1.200

• Defines levels of F&Os

-Findings-Observations

-Best Practices No F&O Closure Gap Assessment to RG 1.200 Disposition of F&O to Risk App.Peer Review PRA UpgradesPeer Review W/New F&Os Closure of F&OClosure of F&O 2Independent ReviewersDocumentationAssessment of Upgrade or UpdateQualifications for Independent ReviewerConcurrent Focused Scope Peer ReviewNote: The final Appendix X process is documented in ADAMS Accession No. ML17095A252.NRC Closure Independent AssessmentPeer ReviewFull Scope Simplified process compared to the alternative process in the ASME/ANS PRA Standard for peer reviewsIA Team has direct access to model of record (MOR) and supporting documentation.IA Team has access to Peer Review Report(s) including text of the original F&O.Process appears suitable for closure of F&Os addressing:

• Documentation issues

• Individual modelling and method errors

• Incorrect F&O's When using both webinar and teleconference (shared screen, and voice connectivity) performing a limited scope IA remotely, appeared to be a suitable and capable manner to support IA reviewers role and responsibilities.The IA provides guidance for closure of the F&Os to be documented with a pedigree for retention during auditing and inspection purposes.

Plant A*IA Team (Vendor)Plant B*IA Team (Vendor)*Concurrent Focused Scope*Remote reviewer participationPlant C*IA Team (Vendor)*Concurrent Focused Scope*Reliance on SR met at CC-II*No justification for upgrade or update

• Incomplete documentation for closureNote: The NRC staff observation report is documented in ADAMS Accessions No. ML17095A252.

The NRC staff accepted the final version of the Appendix X guidance in a letter to NEI May 3, 2017 with the following conditions of acceptance (ADAMS Accession No. ML17079A427).Conditions of Acceptance:1)Independent Assessment process does not include review of the closure of F&Os that include PRA upgrades: Focused scope peer review still required for PRA upgrades. 2)The licensee should adhere to the guidance in Appendix X in its entirety to obviate the need for an in-depth review and/or submittal of F&Os in licensing actions

1. NEI 05-04, Appendix X,Section X.1.3: Use of Remote ReviewersParticipation of remote independent reviewers was not planned and scheduled.

2. NEI 05-04, Appendix X,Section X.1.3: Host Utility Preparation

• A written assessment and justification of explaining why each finding was either a PRA upgrade or maintenance update was not performed.

• Scope of F&Os included in the review and provided to the independent assessment team not clearly understood.3. NEI 05-04, Appendix X,Section X.1.3: Close Out of F&Os by IA

• Unclear independence between review teams and work originators

• IA team did not review MOR with changes incorporatedNote: Note: The NRC staff observation report is documented in ADAMS Accessions No. ML17265A812.

• Staff review of LARs and closure reports identified incomplete information for a streamlined review across regulatory guidelines (i.e., RG 1.200, RG 1.174, and SRP 19.1):

-Scope of IA review (e.g., F&Os, self-assessment findings)

-Concurrent focused scope performed

-Timeline of peer reviews and IA performed

-Written justification for if closure of F&O constituted an upgrade or maintenance update

-IA team assessment of the closure of F&Os against the SR for Met at CC-II

• IA F&O closure process has (so far) resulted in 60 -80% reduction in number of open F&Os

• RG 1.200 guidance for open F&Os still applicable. LAR should include:

-discussion of resolution of applicable F&Os OR-Justification that demonstrates accident sequences or contributors significant to application decision not adversely impacted Endorsement of Appendix X in RG 1.200, Revision 3

• Endorsement of Closure of F&Os will further address:1.Summary of information to be provided in the LAR when crediting Appendix X for closure of F&Os2.Defined Terms for:Model of Record Base Model3. Conditions of Acceptance

• Audits and Acceptance of F&O Closure processNRC staff will continue to perform audits and observations to provide continued monitoring and oversight of the Appendix X process.

• Appendix X Process should be standardized for reliance to:Foster efficiency in staff reviews.Improve adherence to guidance and staff endorsement of the Standard.Establish pedigree for training materials and qualifications.Promote consistency across guidance documents

• Facts and Observations (F&Os)

• Independent Assessment (IA)

• Probabilistic Risk Analysis (PRA)

• American Society of Mechanical Engineers (ASME)

• American Nuclear Society (ANS)

• Regulatory Guide (RG)

• Nuclear Energy Institute (NEI)

• Internal Events (IE)

• Internal Flood (IF)

• Seismic Probabilistic Risk Analysis (SPRA)*Model of Record (MOR)

• Fire Probabilistic Risk Analysis (FPRA)*Capability Category (CC)

• Risk-informed Completion Time (RICT)*Integrated Risk-Informed Leak Rate Testing (ILRT)