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 Observations Regulatory Information Conference Technical Session TH35 Adrienne Driver, Reliability and Risk Analyst March 14, 2018

Background:

New Process for closure of F&Os Industry Guidance and Processes PRA Processes for Regulatory Review Overview of Appendix X: Closure of F&Os Process Industry Pilots and Staff Observations Staff Acceptance of Appendix X Post Acceptance Observations NRC Audits: Crediting F&O Closure Proposed 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 NEI 05-04/07-12/12-16

• Provides standards for peer review of

• Guidance for Peer Review Process a PRA to be used in risk-informed -Assessment of the Capability decisions for commercial nuclear Category (CC) of the Supporting power plants. Requirements (SR), CC-I, CC-II, CC-III

• Defines PRA upgrades and stipulates

• Full Scope when a peer review should be

• Focused Scope performed.

• Gap Assessment to RG 1.200

• Peer Review

• Defines levels of F&Os

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

- Best Practices Peer Review W/

PRA New F&Os Upgrades Disposition of F&O to Risk App.

No F&O Closure Gap Assessment to RG 1.200 Peer Review Closure Closure of of F&O F&O NRC Closure Independent Peer Review Assessment Qualifications for Concurrent Full Scope Documentation Independent Focused Scope Reviewer Peer Review 2 Independent Reviewers Assessment of Upgrade or Update Note: The final Appendix X process is documented in ADAMS Accession No. ML17095A252.

Simplified process compared to the alternative process in the ASME/ANS PRA Standard for peer reviews IA 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&Os 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

• IA Team (Vendor)

• Reliance on SR met at A

CC-II

• No justification for

• IA Team (Vendor) upgrade or update Plant

• Concurrent Focused Scope

• Incomplete documentation for B

• Remote reviewer participation closure Plant

• IA Team (Vendor)

• Concurrent Focused C Scope Note: 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 Reviewers Participation 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 incorporated Note: 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&Os

2. Defined Terms for:

Model of Record Base Model

3. Conditions of Acceptance

• Audits and Acceptance of F&O Closure process NRC 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)

• Capability Category (CC)

• Independent Assessment (IA)

• Risk-informed Completion Time

• Probabilistic Risk Analysis (PRA) (RICT)

• American Society of Mechanical

• Integrated Risk-Informed Leak Rate Engineers (ASME) Testing (ILRT)

• 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)