ML18087A372
| ML18087A372 | |
| Person / Time | |
|---|---|
| Issue date: | 03/14/2018 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| Download: ML18087A372 (14) | |
Text
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
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.
- 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)
- Fire Probabilistic Risk Analysis (FPRA)*Capability Category (CC)