ML24306A163
| ML24306A163 | |
| Person / Time | |
|---|---|
| Issue date: | 11/05/2024 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | Burton M NRC/RES/DRA |
| Shared Package | |
| ML24306A160 | List: |
| References | |
| Download: ML24306A163 (1) | |
Text
MEMORANDUM TO: Mat I. Burton, Chief Performance and Reliability Branch Division of Risk Analysis Office of Nuclear Regulatory Research FROM: Christopher Hunter, Sr. Reliability & Risk Analyst Performance and Reliability Branch Division of Risk Analysis Office of Nuclear Regulatory Research
SUBJECT:
SUMMARY
OF OCTOBER 30, 2024, PUBLIC MEETING TO DISCUSS VARIOUS COMMON-CAUSE FAILURE (CCF) TOPICS On October 30, 2024, the U.S. Nuclear Regulatory Commission (NRC) held a public meeting with the Nuclear Energy Institute (NEI) and other external stakeholders. The announcement for this public meeting is available in ADAMS ( ML24292A053). The purpose of this meeting was to discuss the improving realism in the modeling and treatment of CCFs in NRC event and condition assessments (ECAs). In addition, there was a discussion on external stakeholder engagement in the NRCs Operating Experience (OpE) Data and Parameter Estimation Program. As part of these discussions, both the NRC ( ML24303A222 and ML24303A223) and NEI ( ML24303A221) provided presentations. The enclosure to this document lists the meeting attendees.
NEIs presentation communicated the need to improve realism in the treatment of CCFs in NRC ECAs. The presentation included an overview how improved realism increases transparency and elimination of unnecessary conservatism decreases the burden both the licensees and the NRC. The presentation discussed that CCF defenses and extent of condition evaluations should be considered in NRC ECAs. The presentation also communicated industrys interest on guidance associated with use of alternative CCF data and modeling approaches (e.g., component-specific CCF priors and application of the Causal Alpha Factor Method
[CAFM]). In addition, NEI communicated the industrys continued interest in engaging in NRC parameters updates. The presentation closed with highlighting the next steps the industry believes are needed to move forward on the discussed topics.
Enclosure:
- 1. List of Attendees for October 30, 2024, Public Meeting to Discuss Various CCF Topics CONTACT: Christopher Hunter, RES/DRA/PRB (301) 415-1394November 5, 2024 Signed by Hunter, Christopher on 11/05/24
M. Burton In its presentation, the NRC staff stated their agreement with industrys stakeholders that NRC ECAs should be as realistic as possible, and that the NRC uses a data-driven approach to represent CCFs in a transparent and scrutable manner. The NRC reinforced its approach to the treatment of potential CCF in ECAs, which is provided in NUREG-2225, Basis for Treatment of Potential CCF in the SDP, (ML18033A152). The staff described recent efforts that could potentially improve realism in CCF modeling and treatment of potential CCF in NRC ECAs.
First, the staff described the recently developed component-specific priors that could replace the single generic prior, which includes all CCFs regardless of component type or failure mode. In addition, examples of both the differences in the priors and CCF parameters for key components were provided. Second, the staff provided information on the use of the CAFM, including the associated limitations with the method. Third, the staff communicated that a review of the existing cross-unit CCF modeling in the NRC standardized plant analysis risk (SPAR) models, including the use of the existing CCF parameters is this application, is ongoing. The staff concluded its presentation with providing up-to-date information on the early insights and status of this review.
A discussion on industrys engagement in the NRCs OpE Data and Parameter Estimation Program was held. The discussion was started with a short presentation provided by NRC staff on past experience with industry engagement and the mutual benefits experienced by both the NRC and industry. A discussion continued on potential ways to improve these interactions, including observations about the potential improvements to the licensee data input provided in Institute of Nuclear Power Operations (INPO) Industry Reporting and Information System (IRIS)
System that would increase efficiency and data accuracy. The meeting was concluded when no further comments or questions were identified from the participants, including the public.
ML24306A160; ML24306A163 OFFICE RES/DRA/PRB NRR/DNRL/NCSG RES/DRA/PRB NAME CHunter CH MBurton MB CHunter CH DATE Nov 1, 2024 Nov 5, 2024 Nov 5, 2024