ML26043A459
| ML26043A459 | |
| Person / Time | |
|---|---|
| Site: | 99902028, Nuclear Energy Institute |
| Issue date: | 02/11/2026 |
| From: | Uhle J Nuclear Energy Institute |
| To: | Mark King NRC/EDO, Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| Download: ML26043A459 (0) | |
Text
Jennifer Uhle, Ph.D.
Vice President Technical & Regulatory Services Phone: 202.247.5717 Email: jlu@nei.org February 11, 2026 Mr. Michael King Executive Director for Operations U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Industry Feedback from Recent Fuel Fragmentation, Relocation, and Dispersal and Power Uprate Workshops Project Number: 689
Dear Mr. King,
The Nuclear Energy Institute (NEI)1, on behalf of its members, is writing this letter to provide industrys perspectives from the recent fuel fragmentation, relocation, and dispersal (FFRD) and power uprate review efficiency workshops including discussions related to fuel cycle extensions with increased enrichments and extended burnups. The industry supports the staffs enhancements in the draft IE rule published in January 2025 (as discussed in several ACRS meetings2) that advance more realistic and risk-informed dose criteria to enable LEU+ enrichment levels, but the language introduces unnecessary complexity in areas such as transition break size definitions and determination, risk program criteria, inspection protocols, and reporting obligations that should be eliminated. To that end, recommendations are provided in the attachment that will yield an efficient framework that will ensure public health and safety while enabling power uprates and extended fuel cycles to help meet the nations growing energy demands.
The industrys strategic goal is to safely and economically enable extended cycle lengths across the fleet by establishing the regulatory framework needed to support burnup and enrichment extensions beyond the current legacy limits by 2027. Furthermore, the industry is expanding capacities through successful deployment of power uprates to support national energy goals. To meet these goals, the industry urges the NRC staff to develop a risk-informed LOCA framework that facilitates innovation while maintaining safety in an efficient and durable manner.
1 The Nuclear Energy Institute (NEI) is responsible for establishing unified policy on behalf of its members relating to matters affecting the nuclear energy industry, including the regulatory aspects of generic operational and technical issues. NEIs members include entities licensed to operate commercial nuclear power plants in the United States, nuclear plant designers, major architect and engineering firms, fuel cycle facilities, nuclear materials licensees, and other organizations involved in the nuclear energy industry.
2 ML24319A197, ML25013A080, ML25044A331
Mr. Michael King February 11, 2026 Page 2 Nuclear Energy Institute NEI supports the staffs enhancements in the draft IE rule published in January 2025 that advances more realistic and risk-informed dose criteria to enable LEU+ enrichment levels, including:
more accurate modeling of potential release paths, enhanced suppression pool scrubbing realism, improved steam-line deposition modeling, modernized, risk-informed control-room dose design criteria, alignment of NUREG-2266 for fuel designs up to 10 wt% U-235 and 80 GWd/MTU burnup, treating large break (LB) LOCA as a beyond-design-basis accident, and highlighting important supporting changes to spent fuel pool requirements (10 CFR 50.68) and transportation regulations (10 CFR 71.55).
However, the draft language introduces unnecessary complexity in areas such as transition break size definitions and determination, risk program criteria, inspection protocols, and reporting obligations. Moreover, the accompanying draft regulatory guides specify provisions that are redundant with existing guidance and impose additional burden not commensurate with risk. To support the development of a clear, efficient, and durable rule, the industry recommends changes and clarifications in the attachment.
In addition to the changes to the draft language, the following regulations need to be changed in the wholesale rulemaking to enable the industry to deploy ATF/LEU+/HBU on the industrys timeline without needing to seek exemptions:
10 CFR 50.46 - Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors 10 CFR 50.67 - Accident source term GDC Control Room 10 CFR 50.68 - Criticality accident requirements 10 CFR 51.51(b) - Uranium fuel cycle environmental data - Table S-3 10 CFR 51.52 - Environmental effects of transportation of fuel and waste - Table S-4 10 CFR 71.55 - General requirements for fissile material packaging We hope this information and these recommendations facilitate your rulemaking efforts and we look forward to future dialogue on this subject.
If you have any questions, please contact me or Greg Core at gmc@nei.org or (202) 407-2074.
Sincerely, Dr. Jennifer Uhle Vice President, Technical & Regulatory Services
[Attachment]
Mr. Michael King February 11, 2026 Page 3 Nuclear Energy Institute ATTACHMENT The industry provides the following clarifications and insights to assist the NRC in developing a predictable, efficient, and durable regulatory framework that will enable the safe and clean production of additional nuclear power in the United States.
Clarification on when to Address Fuel Dispersal in Future Submittals The NRC in SECY-15-0148 (ML15230A200) concluded that research and analyses provide reasonable assurance that no imminent safety concern exists with operating reactors associated with the dispersal of high burnup fuel.
The SECY-15-0148 conclusions covered the light water reactor fleet operation up to and included 62 GWD/MTU rod-average burnup. Therefore, the safety assessment supporting SECY-15-0148 continues to be applicable to plants operating in accordance with, or plants uprating within the boundaries of the 2015 fuel design limits, and these plants are not required to modify their license basis to address fuel dispersal consequences.
As part of the December 11-12, 2025, workshop and tabletop exercise, the NRC agreed that the approach identified by the Southern Nuclear Company (SNC) was consistent with past precedent and the updated draft Appendix A to Office Instruction LIC-112 guidance. Specifically, SNCs Hatch planned EPU and MELLLA+ submittal will not address FFRD because Hatch will continue to use the existing fuel system licensing basis and the uprated power level is less than 122% of the original licensed thermal power (OLTP). SNCs approach concluded a further evaluation of FFRD to be unnecessary due to:
- 1)
The proposed path followed the Peach Bottom Units 2 and 3 precedents,
- 2)
Hatch will maintain the maximum rod-average burnup of 62 GWd/MTU,
- 3)
Hatch will operate in a manner consistent with current BWR core design and operational strategies, and
- 4)
The Hatch power uprate application is based on prior NRC approved methodologies.
The same conclusion would apply to other licensees that plan to uprate in a similar fashion. We note that the NRC remarked that EPU LARs for power levels greater than 122% OLTP may require further evaluation since that operation is outside the existing power uprate experience SECY-15-0148 basis. The [FP3.1]SNC position is consistent with SECY150148 and the draft Appendix A to LIC-112, which identifies the review area for Emergency Core Cooling System (ECCS) and LOCA as Bin 2 if (1) NRC-approved safety analysis methods are used within the range of applicability, without significant deviations, and within applicable limitations and conditions; and (2) the maximum rod-average burnup limit of 62 GWd/MTU is maintained, and the plant is operated in a manner consistent with current core design and operational strategies.
The industry requests that the NRC formalize its position on addressing FFRD for power uprates into a more durable regulatory vehicle to improve predictability and stability.
Mr. Michael King February 11, 2026 Page 4 Nuclear Energy Institute Clarification on Licensing Implementation Pathway allowing use of EPRI Alternate Licensing Strategy (ALS) for Addressing FFRD within LOCA The industry requires greater regulatory clarity and predictability regarding the implementation of the EPRI ALS.
This issue was discussed during the December 11-12, 2025, public meeting and tabletop exercises. While EPRI ALS offers a viable pathway for addressing fuel dispersal impacts within LOCA analyses, it does not eliminate the obligation for stations to perform LOCA evaluations across the full spectrum of break sizes. Therefore, the industry believes a policy clarification that explicitly permits the use of EPRI ALS for fuel dispersal considerations is appropriate.
Insights on Proposed 50.46a Risk-Informed LOCA Rule The Increased Enrichment pre-decisional draft rule package released in support of the January 16-17, 2025 ACRS meeting (ML25013A080) contained overly prescriptive and burdensome requirements on the adoption of the voluntary rule which are not commensurate with the risk-significance of LOCA (ML25139A489, ML25148A090: NEI presentation workshop on Risk Significance of Loss of Coolant Accidents and Justification for a Risk-Informed Transition Break Size). Regulations and guidance should enable the use of risk-informed, graded approaches for LOCA assessment. Care should be taken to ensure updated regulations in this area are not overly prescriptive as they are less durable and impose a greater implementation burden due to rigid requirements or the need for exemptions.
Regulatory Guides (RG-1.200, RG-1.174) already exist to enable the use of risk insights and provide sufficient guidance to allow a licensee to submit a license amendment request for approval that utilizes PRA or risk-insights.
The NRC staff should leverage this guidance rather than codifying overly prescriptive requirements, which is the approach taken in the draft §50.46a rule language.
The LOCA Evaluation Model (EM) reporting requirements remain prescriptive and are not commensurate with the risk-significance of LOCA to a plant. In addition, the proposed new requirement to report transient oxidation increases reporting complexity and regulatory burden without providing a corresponding safety benefit. The industry recommends maintaining PCT as the only reportable metric when using the proposed NRC hydrogen-based PCT and transient oxidation limit. As outlined in the workshop held in July 2025 (ML25210A425, NEI presentation LOCA Reporting Workshop), changes which impact compliance are readily covered by other regulations (i.e., 10 CFR 21, §50.72, and §50.73). Therefore, the industry recommends using only annual reporting.
This will provide the NRC staff with the requested awareness regarding changes made to a plants LOCA analyses and/or evaluation methodologies. Alternatively, reporting requirements could be driven by the proximity to the regulatory limit (i.e., 2200 deg-F PCT) thereby accounting for individual plant safety margin.
Mr. Michael King February 11, 2026 Page 5 Nuclear Energy Institute Insights on DG-1261 Rev 1 (Periodic Testing Breakaway Oxidation)
The NRC staff should consider removing the requirement for fuel vendors to periodically report the results of breakaway oxidation testing consistent with the recommendation of the Advisory Committee on Reactor Safeguards (ML25044A331).
Insights on DG-1426 (RI Evaluation for ECCS LWR)
To improve regulatory efficiency, this draft guidance should not be used because it is redundant with other existing regulatory guides (RG-1.200, 1.174). Instead, guidance for risk-informed change control programs under the new LOCA rule should follow RG-1.200 and RG-1.174, which is the same framework as that of all other risk-informed change programs (i.e. TSTF-425, 505, etc.), as evidenced by SERs on risk-informed change programs (i.e.
ML102380477, ML102520083). There is no need for more stringent change control guidance to be developed since LOCA events are not significant contributors to plant risk and use of existing guidance should be acceptable.
Insights on DG-1428 (TBS Applicability)
The current format of DG-1428 provides significant unnecessary implementation burden to licensees considering adoption of §50.46a. Costs to implement the proposed regulatory requirements are conservatively estimated to be on the order of millions of dollars in one time analysis costs (per unit) associated with identifying new inspection locations along with a perpetual cost due to increased inspections (of new locations identified by analysis) of approximately ($1M/Unit-cycle). Industry has already addressed seismic considerations in response to NRC letter ML12053A340. Seismic risk associated with the reactor coolant system boundary is not a significant contributor to plant risk and NUREG-1903 continues to be applicable without additional plant specific seismic analyses, seismic margin assessments, and seismic fragility analyses. Industrys existing aging management programs (AMP), in-service inspection programs (compliant with §50.55a), PWR-specific leak before break (LBB) analyses, and leakage detection in plant operating licenses (Technical Specifications) provide a multi-layer defense-in-depth approach to analyze, inspect, and monitor the reactor coolant system piping to ensure integrity is maintained during operation and under postulated accident scenarios. This multi-layer approach has proven effective based on decades of industry OE.
The NEI 03-08 framework, supported by the industrys Materials Issue Programs3, has enabled the industry to proactively manage and address degradation mechanisms before they impact safety. Additionally, updated analyses were performed and presented to ACRS in December of 2024 using the jointly developed EPRI/NRC tool xLPR to demonstrate the pipe failure frequencies for PWRs are orders of magnitude smaller than that communicated in NUREG-1829. As a result, NUREG-1829 continues to be applicable. Industry recommends the 3Electric Power Research Institute, FRP 2025-008, Responses to the Requests for Additional Information (RAIs) on EPRI Report 3002028673, Loss-Of-Coolant-Accident-Induced Fuel Fragmentation, Relocation and Dispersal with Leak-Before-Break Credit - Alternative Licensing Strategy, April 2024., October 31, 2025.
Mr. Michael King February 11, 2026 Page 6 Nuclear Energy Institute aspects of DG-1428 that require increased implementation burdens (increased dose to nuclear workers and costs) be removed as they are redundant and provide no quantitative improvement in the risk and safety performance of an operating plant. Further, the regulatory guide needs to be flexible to incorporate alternate approaches that better align with the intent of the 10 CFR 50.46a rule, such as Risk Informed Transition Break Size (RI-TBS) determination.
Insights on DG-1434 (LOCA FFRD Assessments)
Industry recognizes the complexity of implementing a risk-informed approach to encompass different Light Water Reactor (LWR) designs and the variations of fuel vendor LOCA analysis methodologies (e.g., best-estimate plus uncertainty vs. Appendix K). As such, industry seeks flexibility in addressing the consequences of fuel dispersal.
Potential approaches include the reclassification of LOCA events above the TBS as beyond design-basis to reduce the conservatisms built into LOCA analysis methodologies (the reduction of conservatism is commensurate with the low-risk). Reduced conservatisms may lead to the demonstration of no cladding rupture above the fine fragmentation burnup threshold or the demonstration that the dispersal of fine fuel fragments does not affect the coolability of the core under LOCA conditions. Similar to the previous discussion for the Hatch application above, the industry also seeks a graded approach to address fuel dispersal consequences that may allow for a reduction of compounding analysis conservatisms to confirm that fuel dispersal is indeed not risk significant.
Insights on DG-1425 (AST Rev 2 draft)
Significant updates to the regulatory framework for the treatment of Alternative Source Terms (RG-1.183),
informed by NRC workshops (ML24008A156, ML24043A264, ML24068A036, ML25262A164), have reduced excess conservatism in the regulatory guidance; however, opportunities for further improvements remain. DG-1425 establishes a requirement to perform a FFRD LOCA dose consequence analysis with acceptance criteria set at approximately 25% of the regulatory limit per §50.67. To improve efficiency, this event could be removed from consideration as the Commission acknowledged that the event is bounded by another event that has already been analyzed (ML21197A067). To improve clarity and regulatory durability, an approved condenser deposition model should be included in DG-1425 prior to final issuance. The current draft guidance allows condenser deposition credit on a case by case basis; however, this approach lacks durability and could result in inconsistent condenser deposition modeling across submittals. Therefore, consistent with the guidance provided for aerosol deposition in steam lines including example calculations that reflect Commission expectations (ML21141A006),
industry requests that the final guidance also include detailed condenser deposition modeling considerations.
The industry appreciates the NRC staffs efforts in advancing a more efficient, risk-informed, and transparent regulatory framework with respect to RG 1.183 R2 as summarized at the September 24, 2025, public workshop (ML25262A095). Through these sustained public meetings, workshops, and clear guidance development, the NRC staff has demonstrated a strong commitment to constructive engagement with the industry and the public. The staffs willingness to explain regulatory intent, share evolving technical thinking, and actively listening to stakeholder feedback has fostered a productive two-way dialogue that improves regulatory clarity, predictability,
Mr. Michael King February 11, 2026 Page 7 Nuclear Energy Institute and implementation quality. These efforts strengthen confidence in the regulatory process and support the safe, timely deployment of fuel innovations, power uprates, and increased enrichment technologies. Therefore, the industry recommends that NRC staff document the positions discussed at the September 2025 workshop related to aerosol removal rates and equipment qualification requirements in a durable regulatory vehicle to support consistent and predictable implementation.