ML25323A415
| ML25323A415 | |
| Person / Time | |
|---|---|
| Issue date: | 12/03/2025 |
| From: | Delosreyes J Licensing Processes Branch |
| To: | Jennivine Rankin Licensing Processes Branch |
| Shared Package | |
| ML25323A413 | List: |
| References | |
| Download: ML25323A415 (0) | |
Text
December 3, 2025 MEMORANDUM TO:
Jennivine K. Rankin, Branch Chief Licensing Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM:
James Delosreyes, Project Manager
/RA/
Licensing Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
SUBJECT:
MEETING
SUMMARY
OF THE SEPTEMBER 18-19, 2025, U.S. NUCLEAR REGULATORY COMMISSIONS ACCIDENT TOLERANT FUEL FRAGMENTATION, RELOCATION, AND DISPERSAL CONSEQUENCES WORKSHOP On September 18-19, 2025, the U.S. Nuclear Regulatory Commission (NRC) staff held a public workshop with representatives of industry to discuss topics related to Fuel Fragmentation, Relocation, and Dispersal (FFRD) including a proposed white paper submittal from the Nuclear Energy Institute (NEI) on materials degradation research and initiatives. The meeting was held in a hybrid format (i.e., attendance in-person, virtual, and teleconference) and conducted over two days. The meeting notice is available in the Agencywide Documents Access and Management System (ADAMS) under Accession No. ML25260A589. The presentation slides are available in ADAMS under Accession No. ML25260A541. The list of attendees is enclosed.
The NRC staff began the public meeting with an introduction and explanation of logistical information. Jen Whitman, NRCs Director of the Division of Safety Systems, and Al Csontos, NEIs Director of Fuels, provided opening and closing remarks. The topics discussed during the meeting are summarized below.
Please direct any inquiries to James Delosreyes at James.Delosreyes@nrc.gov.
BACKGROUND This workshop was the third in a series of workshops to discuss topics related to FFRD to take place over the span of several months with the first two held on May 20-21 and July 30-31, 2025. Most, if not all, of these workshops will also serve as a venue to discuss draft submittals from industry for white papers related to the topics of discussion.
CONTACT:
James Delosreyes, NRR/DORL 301-415-4141
Performance Monitoring Through Inspections and Demonstrating Acceptable Seismic Failure Risk The NRC staff presented on a topic related to performance monitoring as part of a risk informed approach to plant licensing. The topic focused on the role of and managing seismic risk for reactor coolant pressure boundary components, emphasizing that inspections are the most effective tool for ensuring degradation remains within acceptable limits, especially for passive components where other monitoring methods are limited. The presentation reviewed the evolution of risk-informed in-service inspection (RI-ISI) practices which allow for targeted sampling based on risk categories and degradation mechanisms. These approaches aim to optimize inspection scope while maintaining safety margins.
Additionally, the presentation addressed how seismic risk can be managed through existing evaluations like seismic probabilistic risk assessment and margin assessments. It proposed a screening approach to identify and evaluate high-risk welds and materials for potential loss of fracture toughness due to aging. The goal is to demonstrate that seismic-induced failure risk remains lower than that from normal operations, ensuring continued plant safety. The presentation concluded with considerations for fleet-wide and plant-specific inspection strategies to maintain acceptable risk levels.
Demonstration of the Proven Effectiveness of Existing Materials Management and Inspection Programs The Electric Power Research Institute (EPRI) presented next on a proposed white paper being developed in collaboration with NEI. The topic demonstrated the continued effectiveness of the nuclear industrys materials management and inspection programs, emphasizing that current practices remain sufficient to ensure safe plant operation without the need for additional weld inspections or fabrication record searches. The NEI 03-08 Materials Initiative, a cornerstone of industry coordination, was highlighted for its proactive approach to identifying and managing degradation mechanisms. The initiative has received positive feedback from the NRC and is recognized internationally as a model for aging management.
The presentation also reaffirmed the validity of NUREG-1829 conclusions, supported by updated probabilistic fracture mechanics analyses using the xLPR tool. These analyses confirmed that the likelihood of a break larger than the Transition Break Size remains extremely low, even with extended plant lifetimes. RI-ISI programs, along with augmented inspection protocols and leak-before-break evaluations, were shown to effectively target high-risk components. The industrys inspection infrastructure, including the Performance Demonstration Initiative, continues to provide robust assurance of structural integrity across the fleet.
NRC Efficiency Improvements The NEI presented last on regulatory efficiency improvements revolving around the Increased Enrichment (IE) and Title 10 of the Code of Federal Regulations 50.46a/c rulemakings. The IE rulemaking seeks to raise the enrichment limit, supporting advanced fuels, accident-tolerant fuel (ATF), and extended fuel cycles. The previously discontinued 50.46a rule, a voluntary risk-informed alternative to traditional loss-of-coolant accident criteria, and the withdrawn 50.46c rule, which addressed fuel embrittlement, are now being reconsidered in a combined framework. This integrated approach aims to enhance regulatory realism, enable higher burnups and power uprates, and reduce unnecessary burdens while maintaining safety through existing aging management programs and updated analytical models.
DISCUSSION During the open discussion, the NRC staff and industry representatives reviewed survey results on inspection practices for similar metal welds in primary loop piping. It was noted that inspection coverage varies based on reactor design, material types, and historical practices.
While some units continue to inspect these welds regularly, others meet risk-informed requirements through alternative selections, particularly where technical limitations exist. The conversation also addressed whether inspections are being performed on the largest connected piping systems, with examples illustrating how such components are typically categorized under risk-informed frameworks and may warrant targeted sampling.
Further clarification was provided on the use of augmented inspection strategies, such as Appendix L, which focuses on the most fatigue-limiting locations and can complement broader inspection programs. The NRC staff emphasized the importance of documenting this information in the white paper to support a comprehensive understanding of inspection coverage. While some components are no longer inspected due to challenges like cast materials or limited access, the survey was considered broadly representative. The NRC staff encouraged including more detail on inspection locations and rationale to ensure all plants are adequately reflected in the overall evaluation.
The conversation shifted to how seismic risk is being addressed across the fleet, with NRC staff outlining a path forward for demonstrating that seismic risk remains lower than normal operational risk. It was acknowledged that while existing seismic risk analyses show low overall risk and minimal contribution from primary loop piping, these analyses often do not account for how material degradation over time could affect component fragility. To bridge that gap, the NRC staff emphasized the need to integrate multiple sources of technical evidence to build a comprehensive case that piping integrity under seismic loading remains robust, even in the context of aging.
The group discussed how various technical elements can be combined to support this conclusion. While each plant may rely on different pieces of this broader technical framework, the goal is to ensure that, collectively, the evidence demonstrates acceptable seismic performance across the fleet. The NRC staff noted that this integrated approach should be clearly documented, potentially using the screening methodology discussed in earlier presentations, and tailored to reflect plant-specific conditions while maintaining a consistent risk-informed basis.
The details of this latter discussion were captured in email and forwarded to EPRI for consideration in its MRP-480 program available at Accession No. ML25323A523.
PUBLIC COMMENTS A member of the Union of Concerned Scientists emphasized the importance of incorporating seismic risk into the NRCs evaluation process and urged the NRC staff not to compromise on the technical rigor required. The member criticized the notion that plant-specific analyses might not be necessary, calling it unreasonable given the scope of the proposed strategy. The member argued that NRC decisions should be based on technical merit, not industry convenience, and highlighted seismic risk as a critical vulnerability that must be thoroughly addressed.
No regulatory decisions were made during this meeting.
Enclosure:
List of Attendees
Enclosure LIST OF ATTENDEES U.S. Nuclear Regulatory Commission Workshop Accident Tolerant Fuel Fragmentation, Relocation, And Dispersal Consequences September 18-19, 2025 9:00 am - 12:00 pm U.S. Nuclear Regulatory Commission First Name Last Name Steve Bajorek Michelle Bales Ron Ballinger Michael Benson Andrew Bielen Angie Buford Alex Collier James Corson Stephen Cumblidge Vic Cusumano James Delosreyes Elijah Dickson Dave Dijamco Hossein Esmaili Carolyn Fairbanks Richard Fu David Garmon Craig Harrington Emma Haywood Kevin Hsueh Lois James Meena Khanna Scott Krepel John Lehning Anna Luczak Don Marksberry Robert Martin David McClain Sean Meighan Joseph Messina Seung Min Ching Ng Jamie Pelton Ravi Penmetsa Jennie Rankin Aida Rivera-Varona David Rudland Alex Terres Robert Tregoning U.S. Nuclear Regulatory Commission First Name Last Name Chris Van Wert Shilp Vasavada Gokul Vasudevamurthy Weidong Wang Jen Whitman Dan Widrevitz Brandon Wise John Wise On Yee Non-NRC First Name Last Name Organization (if provided)
Victoria Anderson Nuclear Energy Institute (NEI)
Kevin Barber Westinghouse Electric Company (Westinghouse)
Thomas Basso NEI Jana Bergman Curtiss-Wright Greg Broadbent Entergy Jim Cirilli Electric Power Research Institute (EPRI)
Aladar Csontos NEI Kris Cummings NuScale Thomas Damiani EPRI Dennis Earp Duke Jerrod Ewing Westinghouse John Fisher Energy Northwest Rick Fougerousse EPRI Lisa Gerken Framatome Inc. (Framatome)
Nate Glunt EPRI Tim Graf Simpson Gumpertz & Heger Fred Grant Simpson Gumpertz & Heger Stanley Hayes Duke Zachary Hollcraft Alva Energy Jerald Holm Framatome Susan Hoxie-Key Public Zeses Karoutas Westinghouse Austin Keller Duke Thomas Kindred Southern David Kortge Constellation Doug Kull EPRI Matthew Leonard Westinghouse Guangjun Li General Electric (GE)
Edwin Lyman Union of Concerned Scientists Alex Markivich Dominion Tara Matheny Duke Brian Mount Dominion Kurshad Muftuoglu EPRI Non-NRC First Name Last Name Organization (if provided)
Ion Munteanu Energy Northwest Carole Naugle Framatome Matthew Nudi EPRI Stephen OHearn Dominion Pat ORegan EPRI Nathan Palm EPRI Frances Pimentel NEI Ian Porter GE John Richards EPRI Baris Sarikaya Constellation Gideon Schmidt Dominion Fred Smith EPRI Scott Stanchfield Entergy Tim Stuhldreher NEI Ronnie Swain EPRI Lewis Wells Constellation
Package: ML25323A413 Meeting Summary: ML25323A415 Meeting Notice: ML25260A589 Meeting Slides: ML25260A541
- via eConcurrence NRC-001 OFFICE DORL/LLPB/PM DORL/LLPB/LA DORL/LLPB/BC DORL/LLPB/PM NAME JDelosreyes DHarrison JRankin JDelosreyes DATE 11/20/2025 11/25/2025 12/3/2025 12/3/2025