ML25123A001
| ML25123A001 | |
| Person / Time | |
|---|---|
| Issue date: | 05/02/2025 |
| From: | Lundy Pressley NRC/NRR/DRA/APOB |
| To: | |
| References | |
| Download: ML25123A001 (1) | |
Text
CHARTER FOR FRAMEWORK OF FUTURE OVERSIGHT OF RISK INFORMED PROGRAMS & PRA CONFIGURATION CONTROLS - PRA ACCEPTABILITY Objective The purpose of this charter is to establish the structure, scope and expectations to support the framework for future oversight of risk-informed programs (RIPs) to ensure Probabilistic Risk Assessment (PRA) acceptability is maintained through maintenance and upgrades after approval of license amendments of RIPs have been granted to licensees. The objective of this effort is to develop guidance for PRA Configuration Control and a potential infrequent inspection to establish a regulatory footprint in this area, closing an existing oversight gap in the Reactor Oversight Process (ROP); and develop the necessary training and qualifications to support these inspections. The framework proposes a tiered approach concept for future oversight of RIPs and configuration controls within Inspection Manual Chapter 2515, Light Water Reactor Inspection Program Operations Phase, (ADAMS Accession No. ML21062A084) and its appendices. The figure below illustrates the proposed concept. If necessary, ROP program documents will be revised per Inspection Manual Chapter (IMC) 0040, Preparing, Revising and Issuing Documents for the NRC Inspection Manual, (ADAMS Accession No. ML19352E640) and this charter.
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Background===
In 1995, the Commission issued a PRA policy titled, Use of Probabilistic Risk Assessment Methods in Nuclear Regulatory Affairs; Final Policy Statement, 60 FR 42622. This policy statement encourages the use of PRA in all regulatory matters and states that, the use of PRA technology should be increased to the extent supported by the state-of-the-art in PRA methods and data and in a manner that complements the NRCs deterministic approach.Section II of the policy, Summary of Public Comments and NRC Responses, states that the Commission will require PRA quality commensurate with the proposed application.
PRA Quality was first described in SECY-00-0162, Addressing PRA Quality in Risk-Informed Activities, (ADAMS Accession No. ML003732744). PRA Quality was subsequently defined in SECY-04-0118, Plan for Implementation of the Commissions Phased Approach to Probabilistic Risk Assessment Quality, (ADAMS Accession No. ML041470505). SECY-04-0118 presented RG 1.200, An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities, Revision 0, (ADAMS Accession No.ML040630078) as a trial use document to provide a level of confidence for PRAs technical adequacy to support licensing reviews of RIPs.
RG 1.200, Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities, Revision 3, (ADAMS Accession No. ML20238B871) defines PRA Acceptability as measured in terms of PRA scope, level of detail in the PRA, the PRAs conformance with the PRA technical elements in regulatory position C.1.2, and how closely the PRA represents a plants actual configuration and operations. It designates the term PRA acceptability as synonymous with PRA quality and PRA technical adequacy, PRA Configuration Controls ensure approved PRA hazard group models for RIDM remain technically adequate, reflecting the as-built, as-operated plant through changes in the following areas:
Operations Engineering Design Maintenance Plant and industry operating experience Technology, methods or techniques, and tools The following are the PRA Configuration Control requirements for RIPs:
National Fire Protection Association Standard (NFPA 805) 10 CFR 50.48(c)(1), incorporates by reference NFPA 805 as an alternate to 10 CFR 50, Appendix R, Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979. Approved risk-informed fire protection programs in accordance with (IAW) NFPA 805, with a Fire PRA peer reviewed by industry and approved through licensee amendment request (LAR), modify their fire protection license condition to include Risk-Informed Changes that May Be Made Without Prior NRC Approval, allowing licensees to change the program based on risk assessments that are based on the as-built, as operated, and maintained plant; and reflect the operating experience of the plant. Every plant license condition should be reviewed to understand the conditions imposed on the plant. In addition, NFPA 805 section 2.2.9, Plant Change Evaluation, directs the performance of a risk-informed plant change evaluation per section 2.2.4 for changes to previously approved fire protection program elements. Section 2.2.3, Fire Risk Evaluations, requires PRA models used for performance-based evaluations of fire protection features and fire risk evaluations for change analysis described in section 2.2.4 to follow the following requirements:
Use CDF and LERF for measures of risk.
Address the risk contributions associated with all potential risk-significance fire scenarios.
Appropriate for the nature and scope of the change being evaluated, be based on the as-built and as-operated and maintained plant and reflect the operating experience at the plant.
Section 2.2.4, Plant Change Evaluation, requires an integrated assessment of risk, defense-in-depth, and safety margins.
Risk-Informed Completion Time (RICT)
The RICT program includes a license condition requiring the program to be implemented IAW NEI 06-09-A, Revision 0, Risk-Managed Technical Specifications (RMTS) Guidelines.
(ADAMS Accession No. ML12286A322). NEI 06-09-A, Rev 0, section 2.3.4, PRA Technical Adequacy, requires the PRA to be reviewed to the guidance of RG 1.200, Rev 1 for a PRA which meets Capability Category (CC) II for the supporting requirements of the ASME PRA standard. It also requires deviations from CC II to be documented and justified. Section E. of the Admin Technical Specification requires the plant PRA to be based on the as-built, as operated, and maintained plant; and reflect the operating experience at the plant, as specified in RG 1.200 Revision 2.
Surveillance Frequency Control Program (SFCP)
SFCP includes a license condition requiring changes to frequencies under the program to be made in accordance with NEI 04-10, Risk-Informed Method for Control of Surveillance Frequency, Revision 1 (ADAMS No. ML071360456). NEI 04-10, Rev 1, requires the PRA technical adequacy to be addressed through RG 1.200, Revision 1. Plants implementing TSTF-425 shall evaluate their PRAs in accordance with this regulatory guide.
10 CFR 50.69 - Risk-Informed Categorization and treatment of structures, systems, and components for nuclear power reactors 10 CFR 50.69(e)(1) requires licensees to review plant changes, operational practices, and applicable plant and industry operational experience; update PRA as appropriate; and review to be performed in a timely manner not to exceed every two refueling outages. 10 CFR 50.69(e)(2) requires performance monitoring of RISC 1 and 2 components for potential adjustments to categorization or treatment processes as necessary. 10 CFR 50.69(3) requires performance monitoring of RISC-3 components for potential adjustments to the categorization and treatment process. 10 CFR 50.69(2) and (e)3 ensure adverse impact on unreliability data analysis are fed back to the categorization and treatment process.
Overview This framework will provide inspection guidance for PRA Configuration Controls within the baseline inspection program IAW IMC 2515, Appendix A, Risk-Informed Baseline Inspection Program, (ADAMS Accession No. ML21062A084). IMC 2515, Appendix A, provides the basic philosophy of the baseline inspection program, which describes it as indicative and not diagnostic, and evaluates aspects of license programs and processes and their implementation by identifying findings that are indicative of licensee performance problems; it is risk-informed, inspectable areas were selected based on their significance from a risk perspective; and it is the minimum oversight inspection. Licensee programs implemented and informed by PRAs (i.e., Maintenance Rule, RICT, SFCP, 50.69, NFPA 805) are inspected under Appendix A inspection procedures (IPs) 71111.05, Fire Protection, (ADAMS Accession No. ML20237F507), IP 71111.13, Maintenance Risk Assessments and Emergent Work Control, (ADAMS Accession No. ML20238B972), IP 71111.18, Plant Modifications, (ADAMS Accession No. ML20238B974), IP 71111.22, Surveillance Testing, (ADAMS Accession No. ML20324A093), and IP 71111.21N.05, Fire Protection Team Inspection (FTPI), (ADAMS Accession No. ML19084A040). These procedures are part of DRAs tiered approach concept as Tier 1 IPs. Tier 2 IP will focus on PRA Configuration Control program implementation for approved hazard group(s), supporting RIPs.
Tier 3 of the concept may consider IMC 2515, Appendix C, Special and Infrequently Performed Inspections, (ML20321A277) which are IPs implemented for special situations, to evaluate emergent technical issues not related to licensee performance or supplemental inspection or audit. Substantial problems based on exceeded thresholds identified during the Tier 2 IP will be evaluated under Tier 3. This IP will restore confidence on the licensees PRA Configuration Control Program for risk-inform decisionmaking.
This proposed tiered concept for future oversight of RIPs and PRA Configuration Control provides a complete approach to inspections within the ROP. Wherever the guidance for PRA Configuration Controls resides, either in Tier 1 (i.e., within existing baseline procedures), or Tier 2 (i.e., new standalone procedure), training, qualifications, and inspection level of effort, will be the key decision inputs. Those inputs will help shape the recommendations for management review and approval that will be informed by the information gathering and guidance development effort that will include industry feedback.
In addition to the tiered concept, staff should also consider a graded approach for inspection of PRA Configuration Controls depending on the level of adoption by the licensee of advance risk-informed initiatives.
Draft guidance developed for a Tier 2 inspection will be table topped at licensed facilities to inform the working groups decisions and recommendations. Enclosure (1) provides the PRA information gathering and guidance development tabletop plan. To select tabled topped facilities, Enclosure (2) provides a list of licensees with approved risk-informed initiatives. It is recommended that at least eight facilities are table topped accounting for the following combination:
2 Licensee with SFCP 2 Licensee with SFCP and RICT 2 Licensee with SFCP and 50.69 2 Licensee with SFCP, RICT and 50.69 At least 2 facilities with NFPA 805 should be included within the selected facilities.
The tabletop team should be comprised of a regional Senior Risk Analyst (SRA), and two Reliability & Risk Analyst qualified under IMC 1245, Appendix C1, Reactor Operations Inspector.
Scope This framework will layout the necessary milestones to develop a balanced approach to future oversight of RIPs and PRA Configuration Controls. It will provide decisionmakers with proposed courses of action to address future oversight of PRAs within the ROP. Future oversight is represented by a concept tiered approach, including current RIPs implementation procedures, PRA configuration control inspection and an inspection to restore confidence in a licensees configuration controls if found inappropriate to support RIDM.
The output of this charter will serve as an input to revising the oversight process with support from members of the Division of Reactor Oversight (DRO) and all the Regional Offices.
Participation To support this framework, a Working Group was established. The current members of the team are indicated in Table 1, List of working Group Members. If the group determines that additional expertise and involvement is needed, additional staff will participate as necessary.
Meetings Working Group members will meet as necessary to ensure identified milestones are completed.
Communications Project updates will be conducted on a regular basis between the project manager and APOB Branch Chief.
Key Milestones February 2021 Review of Calvert Cliffs PRA changes and technical elements development and implementation guidance.
May 2021 Tier 2 draft guidance for comments to Working Group.
June 2021 Disposition comments. Finalize guidance.
August 2021 Discuss info gathering & guidance development effort (tabletop) with DD during a biweekly meeting.
November 2021 Socialize PRA Acceptability and PRA Configuration Control tabletop at ROP Public Meeting.
February 2022 Discuss PRA Acceptability and PRA Configuration Control at public meeting. Conduct tabletop of the PRA Configuration Control procedure and discuss the information gathering and guidance development effort.
April 2022 Discuss comments resolution from PRA Acceptability and Configuration Control public meeting. Finalize discussion with industry about the information gathering and guidance development effort.
May 2022 Identify and select eight facilities for effort. Commence sessions coordination.
July 2022 Start tabletops at facilities.
December2022 Finalize information tabletops.
March 2023 Enter ROP change control process.
March 2023 Brief NRR management on final recommendations of effort. DDs.
April 2023 Discuss findings at ROP public meeting.
May 2023 Discuss any feedback at ROP Monthly public meeting December 2023 Implement Tier 2 inspection guidance on selected IP. Commence development of Tier 3 inspection guidance.
April 2024 Tier 3 draft guidance for comments to Working Group.
June 2024 Disposition comments. Finalize guidance.
August 2024 Brief NRC management on Tier 3 proposed guidance.
October 2024 Discuss proposed guidance at Public Meeting.
March 2025 Implement Tier 3 inspection guidance.
Disband The Working Group team will disband upon initial implementation of NRC management decisions associated with Tier 2 and Tier 3 inspection guidance.
Time Reporting All activities will be documented in HRMS using CAC No. A11018 Table 1: Working Group Team Members Working Group Team Members Role Meena Khanna SES Sponsor NRR/DRA/APOB (Antonios Zoulis, BC)
Participant NRR/DRA/APOB (Edgardo Torres)
Participant / Project Lead NRR/DRA/APOB (John Hughey)
Participant NRR/DRA/APOB (Lundy Pressley)
Participant NRR/DRA/APOB (Reinaldo Rodriguez)
Participant Region 3 SRA (John Hanna)
Participant NRR/DRA/APLA (Jonathan Evans)
Participant NRR/DRA/APLC (Shilp Vasavada)
Participant Region 1 (Frank Arner, Dave Werkheiser)
Participant Region 2 (Shane Sandal, Andrew Rosebrook)
Participant Region 3 (Laura Kozak, Dariusz Szwarc)
Participant Region 4 (Rick Deese, Davis Loveless)
Participant NRR/DRA (Sunil Weerakkody)
Participant as Needed
Enclosure (1)
PRA Configuration Control Information Gathering & Development Guidance Plan Scope: Gather information and exercise the PRA configuration control inspection guidance at licensed facilities to inform the PRA Acceptability framework in the following areas:
PRA Configuration Control Inspection Guidance Areas:
o Inspection Guidance o Level of Effort o Sample Selection Applicable inspection tiered approach Objectives: To inform the process in the scoped areas, the following objectives are defined:
In the inspection guidance area, this effort will identify:
o PRA configuration program requirements at volunteering facilities. Compare the ASME /ANS PRA configuration control requirements to the licensees program.
NOTE: This is for informational purposes as it could help inform future decisions.
o PRA configuration control inputs statistical breakout. This breakout will evaluate inputs from their data base and independently, for a cross check of items missed by the facility from plant inputs and gather an understanding of inputs that drive maintenance of the PRAs. Review data from prior revisions to the PRA model.
Include the supporting requirements impacted. This statistical analysis will provide a snapshot of past model change drivers and the state of current implementation practices.
Inputs to the PRA consist of changes in the following areas:
Plant:
Engineering o Design o Permanent and Temporary Modifications Operations o Emergency Operating Procedures o Abnormal Operating Procedures o System Operating Procedures o Walkarounds Maintenance o Preventive Maintenance o Routine Maintenance Outages Operating Experience o Plant o Industry Model changes not driven by plant inputs Technology Methods or techniques o Newly Developed Methods Tools o Improvement areas.
o Current state of performance by identifying issues. Any issues of concern will be shared with the licensee to further inform the state of the current implementation practice of their PRA configuration control program.
o Lessons-learned will be shared with the licensee and used to improve the piloting process.
Enclosure (1)
In the level of effort area, this effort will identify:
o Applicable supporting requirements for each risk-informed initiative implemented at the facility.
o Correlation between approved PRA hazard group model(s) to hours spent per sample at each of the piloted facilities. This will inform the number of hours needed for future inspections depending on the risk-informed initiative incorporated.
In the sample selection area, this effort will identify:
o The risk-significance classification for SSCs basic events impacted by the changes reviewed in the statistical breakout. Request the licensee FV and Birnbaum values for the basic events. Include the SAPHIRE importance measures values. This will present a historical picture of risk-significance of the model changes. Potential correlation between risk-significance and changes if any. Define samples by risk-significant components followed by a slice or by risk-ranking changes to the plant.
Applicable inspection tiered approach.
o The final report will provide recommendation on the proper implementation of the tiered approach concept for future oversight of PRAs.
Deliverables: To prepare for this effort, the team lead will prepare an inspection plan. To prepare, the lead should submit an information request to the volunteering facility within minimum 30 days. Team meetings prior to implementation will be scheduled as necessary.
At the end of each info gathering and exercise guidance sessions, the team will produce a report within 15 to 30 days to the APOB Branch Chief. At the end of all sessions, a final report will be issued to DRA and DRO Division Directors, with overall findings, conclusions, and course of action recommendations.
Enclosure (2)
Table 1 - Risk-Informed Initiatives Licensee Status Licensee Region NFPA 805 RICT SFCP 50.69 Seismic Selected Braidwood 1 & 2 III X
X X
Brunswick 1 & 2 II X
X X
Byron 1 & 2 III X
X X
Calvert Cliffs 1 & 2 Constellation Energy I
X X
X X
X Farley 1 & 2 Southern II X
X X
X Hatch 1 & 2 II X
X X
Hope Creek I
X X
Limerick 1 & 2 I
X X
X Millstone 2 Dominion I
X X
X Monticello Xcel Energy III X
X X
X Nine Mile Point 2 I
X X
X Palo Verde 1, 2 & 3 IV X
X X
Peach Bottom 2 & 3 I
X X
Point Beach 1 & 2 III X
X X
Prairie Island 1 & 2 III X
X X
X Robinson 2 II X
X X
Saint Lucie 1 & 2 NextEra NRC to reach out II X
X X
X Sequoyah 1 & 2 II X
X Shearon Harris Duke II X
X X
X South Texas Project 1
&2 STP Nuclear Operating Company IV X
X X
Surry 1 & 2 II X
X Turkey Point 3 & 4 II X
X X
Vogtle 1 & 2 II X
X X
X Watts Bar 1 & 2 II X
X Waterford Entergy NRC to reach out IV X
X X
DC Cook 1 & 2 Indiana Michigan Power Company III X
X X
X NOTE: All licensees with more than one risk-informed initiative are included in the table. All Operating Units have incorporated SFCP into their license.
Enclosure (3)
Revision History for PRA Acceptability Framework Revision Number Description of Change Revision 4 November 22, 2021
- 1. Key Milestone Modifications:
Changed PRA Configuration Control Public Meeting date from January 2022 to February 2022. Meeting set to February 2, 2022.
Added a Public Meeting in May 2022 to discuss resolution of comments with public and finalize discussion with industry about the info gathering and guidance development effort Changed the date to commence identification of facilities to MAY 2022.
Provide a summary of both public meetings to DRA management.
Commence the Info Gathering Effort in August 2022.
Finalize the effort in January 2023 or six months after start of effort. This date can change based on inspector availability and coordination with licensees.
Added March 2023 as the date to deliver the final report. Consistent with the report will be deliver 45 days after completion of the info gathering effort.
Changed NRR Management brief to April 2022 as a result of the March 2023 change.
Change date for final public meeting to discuss findings to June 2023.
Thats give us time to address any comments from NRR ET.
Change the final implementation date of procedure to September 2023.
This date could change depending on the timeliness for the procedural approval process.
- 2. Modified the Info Gathering and Guidance Development Effort scope to include two licensees within the eight with NFPA 805. Added NFPA 805 plants to table 1 (enclosure 2).
Revision 5 Background section updates. Key milestones updates.