Regulatory Guide 1.200
| ML20293A488 | |
| Person / Time | |
|---|---|
| Issue date: | 11/05/2020 |
| From: | Anders Gilbertson, Shilp Vasavada, Sunil Weerakkody NRC/NRR/DRA, NRC/RES/DRA/PRB |
| To: | |
| Weerakkody S | |
| References | |
| Download: ML20293A488 (26) | |
Regulatory Guide 1.200, Revision 3 Briefing for the Advisory Committee on Reactor Safeguards Full Committee Anders Gilbertson Technical Lead / Reliability and Risk Analyst RES/DRA/PRB
Anders.Gilbertson@nrc.gov November 5, 2020
Shilp Vasavada Senior Reliability and Risk Analyst NRR/DRA/APLC
Shilp.Vasavada@nrc.gov Sunil Weerakkody Senior Level Advisor NRR/DRA
Sunil.Weerakkody@nrc.gov
Overview
- Purpose
- Background
- Changes incorporated into Revision 3
- ACRS Subcommittee members feedback
- Primary regulatory driver for Revision 3
- Resolution of public comments on DG-1362
- Path forward
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Purpose To brief the ACRS Full Committee and solicit feedback on the staffs resolution of public comments on the staffs proposed revision 3 to Regulatory Guide (RG) 1.200 (i.e., DG-1362*)
- Available in the Agencywide Document Access and Management System (ADAMS) under accession No. ML19308B636
3 RG 1.200, Revision 3 Briefing for the ACRS Full Committee
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Background
- RG 1.200 provides an approach for determining the technical acceptability of a base probabilistic risk assessment (PRA) model for use in regulatory decisionmaking for light-water reactors (LWRs)
- PRA acceptability is determined with respect to the following aspects of the base PRA:
- Scope
- Level of detail
- Conformance to consensus PRA standard technical elements (i.e., technical robustness)
- Plant representation
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Background - PRA Acceptability
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Each element depends on the other in order to demonstrate PRA acceptability This paradigm obviates the need for an in- depth staff review of the base PRA model Draft Final
Background - PRA Acceptability (cont)
6 RG 1.200, Revision 3 Briefing for the ACRS Full Committee
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Risk-Informed Inservice Inspection
50.69 SSC Categorization TSTF-425, Surveillance Frequency Control Prgm.
NFPA-805, Risk-Informed Fire Protection RITS-4b, Risk-Informed Completion Times Required scope, level of detail, technical robustness, and plant representation
- Greater reliance on PRA
- More flexibility for licensee
- More complex staff review Draft Final
Changes incorporated into RG 1.200,
Revision 3
- Endorses new industry documents:
- NEI 17-07, Revision 2 (ML19241A615)
- Consolidates predecessor industry PRA peer review guidance for different hazard groups
- PWROG-19027-NP, Revision 2 (ML20213C660)
- Includes requirements for determining acceptability of newly developed methods (NDMs) and necessary submittal documentation
- Includes process for differentiating between PRA
maintenance and a PRA upgrade
- ASME/ANS RA-S Case 1 (i.e., the seismic code case)
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Changes incorporated into RG 1.200,
Revision 3 (cont)
- Provides a new glossary of terms
- Some terms adopted directly from PWROG-
19027-NP
- Provides descriptions of hazards to be considered in the development of a PRA
RG 1.200, Revision 3, retains the staff endorsement of ASME/ANS RA-Sa-2009
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Draft Final
ACRS Subcommittee Members Feedback
- Subcommittee members did not identify need for changes
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Draft Final
Primary Regulatory Driver for RG 1.200,
Revision 3
- Evolution of the peer review process
- Gap in Rev. 2 of RG 1.200 with respect to peer review of NDMs
- Significance of closing this gap, specifically for (Risk-Informed Technical Specification (RITS)-4b)
- Strategy to close this gap using PWROG-19027- NP and NEI 17-07
10
RG 1.200, Revision 3 Briefing for the ACRS Full Committee
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Draft Final
A Gap in RG 1.200 and the ASME/ANS
Level 1/LERF PRA Standard
- For each technical element, the ASME/ANS Level 1/LERF PRA
standard provides high-level requirements (HLRs) and supporting requirements (SRs).
- 2009 version of the ASME/ANS Level 1/LERF PRA standard endorsed via Revision 2 to RG 1.200 does not provide HLRs or SRs for NDMs; Furthermore, there is no definition of what constitutes an NDM.
- This gap resulted in inefficiencies in the staffs review of NFPA 805 applications and loss of confidence of the peer review method to adequately peer review NDMs.
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Importance of Closing the Gap; Base PRA
Acceptability for an Application
12 RG 1.200, Revision 3 Briefing for the ACRS Full Committee
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Risk-Informed Inservice Inspection
50.69 SSC Categorization TSTF-425, Surveillance Frequency Control Prgm.
NFPA-805, Risk-Informed Fire Protection RITS-4b, Risk-Informed Completion Times Required scope, level of detail, technical robustness, and plant representation
- Greater reliance on PRA
- More flexibility for licensee
- More complex staff review Draft Final
Current Solution to the Gap
- For RITS-4b applications, staff has imposed the following Administrative Technical Specification (TS)/License Condition:
...and any change in the PRA methods to assess risk that are outside these approval boundaries require prior NRC approval.
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Leveraging the Commission Endorsed Peer Review Process to Close Gap
SECY-99-256: Rulemaking Plan for Risk-Informing Special Treatment Requirements, October 29, 1999
COMNJD-03-0002, Stabilizing the PRA Quality Expectations and Requirements, September 8, 2003
SECY-04-0118, Plan for the Implementation of the Commissions Phased Approach to Probabilistic Risk Assessment Quality, July 13,
2004
SRM-SRM-SECY-04-0118, Plan for the Implementation of the Commissions Phased Approach to Probabilistic Risk Assessment Quality, October 6, 2004.
Establishment of the peer review process using RG 1.200 and consensus standards
Peer review process acknowledged in regulations (10 CFR 50.69, November 2004)
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Approach to Close the Gap in RG 1.200,
Revision 3
- PWROG-19027-NP, Revision 2:
- Provides definitions related to NDMs, PRA maintenance, and PRA upgrade.
- Provides 6 HLRs and 21 SRs for peer review of NDMs (Are being considered for inclusion in the next edition of the ASME/ANS
Level 1/LERF PRA Standard)
- NEI 17-07, Revision 2:
- Delineates the process that peer reviewers must use to peer review NDMs in addition to other technical elements of the PRA.
- Emphasis has been added to close as opposed to disposition peer review finding relating to NDMs prior to using them in PRA models.
15 RG 1.200, Revision 3 Briefing for the ACRS Full Committee
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Public Comments on DG-1362: Summary
- DG-1362 issued for public comment on 07/01/2020
- 30-day comment period ending 07/31/2020
- Received 19 public comments
- Nuclear Energy Institute (NEI; 15 comments including text in transmittal letter)
- Pressurized Water Reactor Owners Group (PWROG; 3 comments)
- Individual (1 comment)
- Public comments included responses to two questions in Federal Register notice (FRN) on the closure of peer review findings using an NRC-endorsed approach
- PWROG submitted updated report PWROG-19027-NP,
Revision 2, with its public comments
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Draft Final
Changes to DG-1362 Based on Public Comments
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Synopsis of Comment Synopsis of Change to DG-1362 Peer review of PRAs that credit planned modifications Clarified expectations for PRAs of operating plants that credit planned modifications
- Considered as a special circumstance
- Staff will address on case-by-case basis
- Peer review and submittal documentation should clearly identify and describe such modifications and design changes Draft Final
Changes to DG-1362 Based on Public Comments
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Synopsis of Comment Synopsis of Change to DG-1362 Correcting the definition of PRA
acceptability Added context to the definition of PRA
acceptability
- Determined for each risk-informed application
- Considers staff positions in RG 1.200, in application-specific regulatory guidance, and any related requirements Draft Final
Changes to DG-1362 Based on Public Comments
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Synopsis of Comment Synopsis of Change to DG-1362 Clarification of peer review of PRA
upgrade(s)
Clarified expectations for peer review of PRA upgrade(s)
- Performed prior to using the upgraded PRA model in support of a PRA application
- Either for an approved risk-informed program or in the submittal of a risk-informed PRA
application for NRC review
- Use of a newly developed method (NDM) in a PRA
is considered a PRA upgrade Draft Final
Changes to DG-1362 Based on Public Comments
20
RG 1.200, Revision 3 Briefing for the ACRS Full Committee
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Synopsis of Comment Synopsis of Change to DG-1362 Clarifying when differences between the 2005 and 2009 version of the Level 1/LERF PRA
standard should be identified in support of a license amendment request Clarified that differences between the 2005 and
2009 version of the Level 1/LERF PRA Standard need to be addressed only if 2005 version used to demonstrate base PRA acceptability Draft Final
Changes to DG-1362 Based on Public Comments
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Synopsis of Comment Synopsis of Change to DG-1362 Ensuring consistency of Appendix D to RG
1.200, Revision 3, Other Hazards, with Part 6 of the 2009 version of Level
1/LERF PRA Standard (ASME/ANS RA-Sa-
2009)
Revised Appendix D, Other Hazards to be consistent with Part 6 of the 2009 version of Level 1/LERF PRA Standard (ASME/ANS RA-Sa-
2009)
Draft Final
Changes to DG-1362 Based on Public Comments
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Synopsis of Comment Synopsis of Change to DG-1362 Removal of an clarification to NEI 17-07, Revision 2, on the documentation of the resolution of peer review findings Public comment identified guidance in NEI 17-07, Revision 2, that addressed a clarification in the public release version of DG-1362 Removal of an clarification to PWROG-
19027-NP, Revision 2, regarding PRA upgrade determination process PWROG-19027-NP, Revision 2, addressed a clarification in public release version of DG-1362 Draft Final
Changes to DG-1362 Based on Public Comments
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Synopsis of Comment Synopsis of Change to DG-1362 Closure of peer review findings (answers to FRN
questions)
Added expectations for disposition of peer review findings from any peer reviews
- Findings should be evaluated for their impact on risk-informed application
- Addressed with documented justification and necessary changes to the PRA
- Prior to use of PRA in risk-informed application Draft Final
Public Comments Resulting in No Changes to DG-1362
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Synopsis of Comment Synopsis of Change to DG-1362 Availability of RG 1.200,
Revision 2 for use after issuance of Revision 3
- Comment was addressed via publicly available NRC
staff response; It explicitly states that Revision 2 is not being withdrawn and, therefore, there is no need to modify DG.
- This practice is consistent with other RG revisions
- Staff, however, anticipates one revision of RG 1.200 to be followed for a given PRA application
- Deviations from the referenced revision of RG 1.200
used in an application submitted to the NRC, including alternatives from other revisions of RG 1.200, need to be identified and justified Draft Final
Public Comments Resulting in No Changes to DG-1362
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Synopsis of Comment Synopsis of Change to DG-1362 Change use of the term application to narrower term "licensing application" throughout DG-1362
-
The term application is used in RG 1.200
consistent with the definition of the term PRA
application from ASME/ANS RA-Sa-2009, as endorsed by the NRC
-
Application-specific staff positions on PRA
acceptability exists in corresponding guidance (e.g.,
Maintenance Rule, Integrated Leak Rate Test)
-
Change could challenge NRC staffs confidence in initiatives that rely heavily on PRA results (e.g.,
risk-informed Technical Specification completion time changes), especially post-NRC approval of a license amendment request Draft Final
Path Forward
26
- Staff considers ACRS Full Committee feedback
- Final reviews and concurrence
11/5/20
Draft Final