ML24313A015
| ML24313A015 | |
| Person / Time | |
|---|---|
| Issue date: | 02/12/2025 |
| From: | Sayoc E NRC/NRR/DNRL/NLIB |
| To: | NRC/NRR/DNRL/NLIB |
| References | |
| Download: ML24313A015 (8) | |
Text
Enclosure 2 U.S. NUCLEAR REGULATORY COMMISSION
SUMMARY
OF THE MAY 23, 2024, OBSERVATION PUBLIC MEETING TO DISCUSS PUBLIC COMMENT RESPONSES AND PROPOSED CHANGES TO SUBSEQUENT LICENSE RENEWAL GUIDANCE Meeting Summary On July 11, 2023, the U.S. Nuclear Regulatory Commission (NRC) published revisions to the Subsequent License Renewal (SLR) Guidance Documents, and a supplement to the associated Technical Bases Document, draft for comment, in the Federal Register (88 FR 44160), Docket ID NRC-2023-0096.
As part of NRCs outreach process, the NRC staff conducted a 60-day comment period (which was subsequently extended to 90-days), during which 202 comments were received. The NRC staff held an information public meeting on May 23, 2024, at the NRC Headquarters in Rockville, Maryland to discuss the NRCs response to select public comments and proposed changes to the SLR guidance documents. The NRC staff provided meeting materials and presentation slides ahead of the public meeting.1,2,3 The observation public meeting started at 9:00 am. The following summarizes major points made during the meeting:
The meeting started with introductions, meeting context, background information, public comments overview, and project updates. The NRC staff opened by stating that this was the fourth public meeting on the SLR Guidance update project and that these meetings are important for the NRC to carry out guidance development that is open, transparent, and inclusive to our stakeholders and the public. The staff provided and overview of the guidance update process, the comments received, and major project milestone dates, including the estimated publication of the Final SLR Guidance in February 2025. During the public comment period, from July 11, 2023 to October 11, 2023,the NRC received 202 public comments from industry representatives (IR) and independent consultants on the draft Revision 1 guidance and the original Revision 0 guidance (comments were unrelated to changes made in Revision 1). The wide range of topics related to SLR application review efficiency, aging management review (AMR) items, aging management programs (AMPs),
references, corrective actions and inspections, alternative techniques and technologies for inspections, formatting, and clarifications. The NRC staff endeavored to address all notable comments.
The purpose of the meeting was 1) to provide a status of the SLR guidance update project,
- 2) to provide an overview of public comments received and staffs preliminary assessments, and 3) to engage in discussions to accept feedback on proposed changes. The NRC staff 1 U.S. NRC, NRC SLR Guidance Public Comment Crosswalk, May 23, 2024, (Agencywide Documents and Access Management System (ADAMS) Accession No. ML24131A137).
2 U.S. NRC, NRC SLR Guidance Update 5-23-24 Public Meeting Slides, May 23, 2024, (ML24131A085).
3 U.S. NRC, Subsequent License Renewal May 23, 2024 Public Meeting, Revised Meeting Slides, May 23, 2024, (ML24141A231).
2 clarified that no new comments were being accepted, and no staff decisions, findings, or commitments were to be made during the public meeting.
Public comments 20, 21, and 32-000 relate to the reduction in NRC staff review time for SLR applications by implementing time saving measures such as referencing first license renewal applications, reviewing proposed changes only, leveraging existing corrective action programs (CAP) and operating experience (OE), targeted scoping and screening reviews, eliminating detailed AMP descriptions, and verifying AMP consistency claims by auditing a sample 20% of AMP Basis Documents. While the NRC staff did not agree with the specific recommendations, the staff agreed with intent of the comment, to implement efficiencies in the review process where appropriate, by developing a License Renewal Roadmap (SECY-24-0026)4 to ensure timely and predictable reviews including implementing a tiered approach for safety reviews, tailoring the level of review by incorporating risk insights, leveraging operating programs and previous reviews, and relying more on NRC and industry OE.
For comments 3, 11, 12, and 17, on the elimination of One-Time Inspections, IRs stated that once the plant has conducted inspections to better understand and confirm the age-related degradation, they can proceed to a periodic or condition monitoring program. IRs added that extent of condition evaluations are well established and effective at plants and serve the same function as One-Time Inspections. The NRC staff acknowledge the feedback and would take them into consideration for guidance update.
Public comments 6, 7, 8, 9, 10, 15, 16, 18,32-017, and 32-025, related to the elimination of prescriptive corrective action (PCA) inspections related to AMPs XI.M18, XI.M20, XI.M21A, XI.M27, XI.M29, XI.M36, XI.M38, and XI.M42. IRs pointed out that PCAs (typically involving inspection scope expansion) added to the AMPs are unnecessary as plants have CAP that are well established and effective, require management and engineers technical expertise which might be more efficiently used to manage AMPs and plant systems, and in some cases are problematic or difficult to implement. The NRC staff explained that PCAs were added to the GALL-SLR, Revision 0, as the staff saw enough instances where the follow-on holistic analysis and corrective actions for aging conditions were not taking place, which led the staff to make the guidance more prescriptive. IRs recommended conducting AMP effectiveness reviews; incorporating license renewal inspections within 10 CFR Part 505 space; and/or implementing plant management/engineer approved and validated extent of condition evaluations. The NRC staff said they would consider the recommendations and are looking to add more flexibility in the guidance, but they have not fully endorsed AMP effectiveness reviews.
Public comment 9, related to AMP XI.M27, Fire Water System (FWS), proposed elimination of prescriptive follow-up inspections as plant CAPs are well established and effective. IRs stated there is no need for extent of condition evaluations for FWS, or performing leakage tests to determine if conditions are localized or widespread because the entire system is flow tested where possible. The NRC staff acknowledged and said they would consider the feedback.
4 U.S. NRC, SECY-24-0026: Achieving Timely Completion of License Renewal Safety and Environmental Reviews (License Renewal Roadmap, April 11, 2024, (ML24059A131).
5 Title 10 of the Code of Federal Regulations (CFR) Part 50, Domestic Licensing of Production and Utilization Facilities.
3 For public comments32-013, 32-016,32-021, 32-022, and 32-054 on the elimination of opportunistic inspections whenever components are made accessible, the staff agreed for AMPs, XI.M17, Flow Accelerated Corrosion, XI.M18, Bolting Integrity, and XI.M21A, Closed Treated Water Systems, XI.M24, Compressed Air Monitoring, and XI.M38, Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components. IRs indicated this change was a positive step and would alleviate significant administrative burden from the plants.
Public comment 32-020 relates to XI.M21A, Closed Treated Water Systems, proposed removal of corrosion inspection guidance. An IR from Comanche Peak Nuclear Power Plant reported on OE6 related to carbon steel lines exposed to treated water with localized reoccurring corrosion due to undersized welds that were caused by human error during construction/installation, not by any aging mechanism, which supports elimination of corrosion inspections. The IR added that chemistry monitoring of treated water would be a better means to detect corrosion rather than direct inspections. NRC staff acknowledged the OE and stated they will consider the feedback.
Public comment 32-024 pertains to AMP XI.M27, "Fire Water System," proposed revision of Table XI.M27-1 to perform internal inspections of sprinkler system piping as a one-time inspection, based on LR-ISG-2011-04.7 IRs pointed out that in LR-ISG-2011-04 the NRC staff acknowledged that oxygen can be introduced into the sprinkler system each time the system is opened, thus accelerating the potential for corrosion. The IR added that there is reasonable assurance that unacceptable flow blockage will not occur through the Subsequent Period of Extended Operation if inspections following 55 years do not identify unacceptable flow blockage. The NRC staff noted the feedback, which they stated would be considered for updating guidance.
Public comment 32-029 and 32-030 pertain to AMP XI.M27, Fire Water System, and the elimination of recommendations to perform fire pump suction strainer and fire pump intake screen inspections annually and after system actuation. An IR stated that the AMP refers to National Fire Protection Association (NFPA) 258, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, which are written generically for buildings and not specifically for nuclear power plants. The IR added that there is no credible blockage impacting the ability for fire pumps to operate and the recommended inspections are dangerous, with OE on diver deaths while inspecting intake screens. An IR cautioned that it would likely result in plants needing to take exceptions to AMP inspections due to undue risks from conducting the inspections. The IR added that visual inspections are unnecessary as pumps are pulled out of service for refurbishments with regular flow tests conducted. An IR acknowledged that the NRC staffs proposal of conducting inspections every five years provides significant relief over conducting them at every pump run (usually monthly). The NRC staff stated that they looked at relevant OE, NFPA 25 recommended inspections and tests, and recurring exceptions the guidance. The NRC staff acknowledged there were exceptions submitted, but the exceptions did not indicate that 6 Luminant, Vistra Operating Co., LLC., Comanche Peak Nuclear Power Plant, Units 1 and 2 - License Renewal Application Revision 0 - Supplement 2, April 24, 2023, (ML23114A377).
7 U.S. NRC, LR-ISG-2011-04, FINAL LR-ISG 2011-04: Updated Aging Management Criteria for Reactor Vessel Internal Components for Pressurized Water Reactors, May 28, 2013, (ML12270A436).
8 NFPA, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, 2023 Edition, https://www.nfpa.org/codes-and-standards/nfpa-25-standard-development/25.
4 there were fleet wide issues with implementing the AMP guidance. The NRC staff noted the feedback, which they stated would be considered for updating guidance.
Public comment 32-031 on AMP XI.M27, Fire Water System, relates to the removal of new footnote (f) related to hose station flow testing. An IR recommended the NRC staff look at the NFPA 149 definition of standpipe zones. The IR added there are no nuclear power plants that have multiple zones. The NRC staff noted the feedback, which they stated would be considered for updating guidance.
Public comment 32-032 on AMP XI.M27, Fire Water System, recommends the acknowledgement of alternative methods described in NFPA 25 for verifying FWS intended functions, to alleviate the need to take exceptions to the AMP. The NRC staff stated their concern with alternative methods was that there could be limitations which are not yet fully understood. Having licenses take exceptions with details on the alternative methods will allow the staff to determine if the alternative method meets the intent of the guidance. The NRC staff noted the feedback, which they stated would be considered for updating guidance.
Public comment 32-115 on AMP XI.33, Selective Leaching relates to substantial changes to guidance imposing significant burden on stations based on a single isolated event. An IR inquired what information should be provided as technical justification for the option to use reduced inspection sample sizes (i.e., 3% with a max. of 10 components). The NRC staff replied generally that the focus of the AMP is on grey cast iron piping, and that recent safety evaluations provide information such as soil corrosivity, OE, inspection details and results, and types of coatings. The NRC staff added that Information Notice 2020-0410 provides OE on selective leaching but it was not intended to be an exhaustive list, and the staff is aware of other instances of significant external surface selective leaching of buried gray cast iron piping.
Public comment 32-041, on AMP XI.M33, Selective Leaching, related to the recommendation to remove opportunistic inspections whenever components are made accessible. The IR recommended that the AMP include some of the aspects brought up in the larger opportunistic inspection comment related to multiple AMPs, such as avoiding unnecessary inspections for components opened regularly. The IR noted there is no need to do frequent selective leaching inspections as selective leaching is a slow acting phenomenon.
Public comment 32-042 on AMP XI.M33, Selective Leaching, relates to the inclusion of hardness testing as an available option for inspections for selective leaching, with acceptance criteria from Generic Aging Lessons Learned Report, Revision 211. An IR stated that the intent here is to provide industry with as many methods as possible to detect selective leaching. Hardness testing would be used to detect selective leaching (without damaging the component) and the test results could drive follow-up with corrective actions if 9
NFPA, Standard for the Installation of Standpipe and Hose Systems, 2024 Edition, https://www.nfpa.org/codes-and-standards/nfpa-14-standard-development/14.
10 U.S. NRC, NRC Information Notice 2020-04: Operating Experience Regarding Failure of Buried Fire Protection Main Yard Piping, December 17, 2020, (ML20223A333).
11 U.S. NRC, GALL Report, NUREG-1801 Rev 2 "Generic Aging Lessons Learned (GALL) Report" Final Report, Revision 2, December 31, 2010, (ML103490041).
5 the condition is present. The NRC staff noted the feedback, which they stated would be considered for updating guidance.
Public comment 13 on AMP XI.M33, Selective Leaching, relates to the elimination of prescriptive follow-up inspections and instead allowing for determination by CAP analysis.
An IR stated that selective leaching is a complex localized issue and aging effect.
Consideration of extent of condition is warranted when unacceptable conditions are found and should be projected through the period of extended operation (PEO). Inspection scope expansion should be based on these analysis as opposed to being automatically implemented. The NRC staff noted the feedback, which they stated would be considered for updating guidance.
Public comment 29-024 on AMP XI.33, Selective Leaching related to including additional non-destructive examination (NDE) techniques. IRs pointed out that NDE techniques (such as screening techniques and volumetric examination) have been studied, tested, shown effective, and well documented in industry reports such as in ASME Small Bore Piping Programs and Electric Power Research Institute reports. IRs cited precedence that other AMPs, such XI.M41, Buried and Underground Piping and Tanks, allow for NDE techniques so long as the techniques are demonstrated effective by applicant. It was added that taking exceptions and providing justification is an unnecessary added administrative burden. An IR summarized that the NDE would not be blanket replacements to the AMPs visual and mechanical inspections, but the NDE would be used where it makes sense, with proper justification. The NRC staff pointed out that industry OE and technical reports were some of the bases for reduced overall inspection sample sizes. They added that there are several materials in the industry that are susceptible to selective leaching, and it is uncertain whether sufficient testing has been done for all these materials, therefore, at this point it may be premature to apply recommended NDE techniques. The NRC staff noted the feedback, which they stated would be considered for updating guidance.
Public comments 25,32-116, and 32-068 on new AMP XI.M43, High-density Polyethylene (HDPE) Piping and Carbon Fiber Reinforced Polymer (CFRP) Repaired Piping, related to eliminating the AMP as there is no OE or adequate technical basis. The NRC staff stated there is proprietary OE that was age-related. The NRC staff pointed out that despite improved age-related material properties, CFRP and HDPE do have aging effects. The new AMP guidance is based on OE and practical knowledge that plastics over time, exposed to water and higher temperatures, change properties, such as elasticity and becomes brittle. In XI.M43 the NRC staff implemented an inspection program that calls for inspection of one, ten-foot section every ten-years, which can be replaced with pressure tests. The staff added that this is reasonable guidance for these new materials with limited OE having recently been applied to the nuclear industry. In addition, the staff added that licenses can take credit for similar inspections such as those outlined in ASME, Section XI12 In-service Inspections, NRC GL 89-1313 piping inspections, or vendor required CFRP inspections. It is difficult to decouple installation versus aging related degradation, so the AMP is a conservative approach to managing CFRP and HDPE aging effects. The NRC staff clarified that the AMP is for managing the aging of the internal and external surfaces of buried, underground, safety-related, and in-scope non-safety-related (HDPE) piping and carbon fiber-reinforced polymer (CFRP)-repaired piping.
12 ASME Code,Section XI, In-Service Inspection of Nuclear Powers Plant Components.
13 U.S. NRC, GL-89-13, Service Water System Problems Affecting Safety-Related Equipment, July 18, 1989, https://www.nrc.gov/reading-rm/doc-collections/gen-comm/gen-letters/1989/gl89013.html
6 Public comment 24 and 32-089 on AMP XI.M43, HDPE Piping and CFRP Repaired Piping, related to eliminating PCA. An IR explained that the AMP acceptance criteria is based on projecting degradation to end of PEO, and that many programs start 10 years prior to PEO so you are projecting out very far, typically 30 years. The IR added that it may be better to project the degradation condition to the next inspection. The feedback was noted by the NRC staff and they indicated the feedback would be considered for updating guidance.
Public comment 29-030 relates to clarifying which AMP should be credited with managing effects of aging for buried and above-ground non-safety-related HDPE piping. In particular, IRs pointed out that further clarification on the scope of the new AMP XI.M43 is needed. IRs offered arguments that suggested that certain components were already covered by XI.M41 and that XI.M43 may not be necessary. The feedback was noted by the NRC staff and they indicated further clarification on XI.M43 scope would be provided.
The following public comments related to AMP XI.M43 were included in the meeting slides and were collectively discussed on a high level: 29-006 on deletion of loss of material, exposure to temperature and moisture in AMRs;29-007 on deletion of exposure to moisture as an aging mechanism;29-031 on deletion of loss of material due to radiation, temperature, and moisture;32-113 on removal of delamination and disbonding from loss of material definition and removal of flow blockage as an applicable aging effect,29-032 on the deletion of accumulation of particulate fouling as an aging mechanism;29-033 on the expansion of the AMP scope to also address external applications of CFRP;32-001 on the removal of cracking as an applicable aging effect for CFRP; and 32-078 on the clarification if the frequency and scope in Table XI.M43-2 for the tests and inspections for HDPE and CFRP. The feedback was noted by the NRC staff and they acknowledged that further clarification on XI.M43 application, environments, aging mechanisms, and tests and inspections is needed.
IRs concluded that given the newness of AMP XI.M43, the complexity of the guidance, and the many changes being proposed, industry should be given the opportunity to see the draft changes to validate clarity, offer technical insights, and ensure the guidance can be implemented. IRs requested a public meeting in the near future dedicated towards discussing technical features of the new AMP XI.M43. Historically several meetings have been conducted between NRC and industry for new AMPs. The NRC staff agreed to consider modifications for clarity, to share a draft of the AMP with comments incorporated, and to conduct a dedicated public meeting in the near future.
IRs confirmed that public comment 32-099, which the NRC staff agreed with, relating to non-ASME Code component volumetric inspections referring to inspections similar to VT-1 and VT-3, primarily pertain to AMPs XI.M36 and XI.M38.
Public comment 29-027 on AMP XI.M41, Buried and Underground Piping and Tanks related to deleting the 25 percent inspection sample size for internal volumetric examinations of piping because internal volumetric exams should be treated equivalent to any external visual exams. IRs stated volumetric examinations are more accurate and should be given more emphasis than surface visual inspections. The NRC staffs partial agreement of the comment and proposed revisions were deemed to be a reasonable middle ground by IRs.
7 Public comment 32-055 on XI.M41, Buried and Underground Piping and Tanks, relates to the elimination or clarification of the coating recommendation for buried cementitious piping.
An IR stated that buried polymerically coated cementitious piping is rare in nuclear power plants and typically out of license renewal scope. There is a potential for automatic exceptions and the IRs recommend removing the guidance to eliminate the need for exceptions. The feedback was noted by the NRC staff and they indicated the feedback would be considered for updating guidance.
Public comment 32-067 on AMP XI.M42, Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks, relates to the elimination of PCA. An IR stated that proposed scope expansion for inspections were based on coating that are sacrificially designed to wear away and not a true aging mechanism. The feedback was noted by the NRC staff and they indicated the feedback would be considered for updating guidance.
Public comment 32-101 relates to the deletion of classification of Long-term loss of material due to general corrosion associated with GALL-SLR and SRP-SLR line items and applicable AMPs. IRs explain that it is unclear why there is a distinction between long-term loss of material due to general corrosion and regular loss of material due to general corrosion, the AMR items are essentially treated the same and results in a significant increase in AMR line items that are largely unnecessary. The feedback was noted by the NRC staff and they indicated the feedback would be considered for updating guidance.
Public comment 32-102 relates to the elimination of SRP-SLR further evaluation Sections 3.2.2.2.7, 3.3.2.2.7, and 3.4.2.2.6 on recurring internal corrosion. An IR pointed out that internal corrosion is now a well know aging mechanism and that through wall or thickness under 50% for pipes in service through the period of extended operation is expected. As such industry conducts inspections and replacements under corrective action programs. The feedback was noted by the NRC staff and they indicated the feedback would be considered for updating guidance.
Public comment 19 relates to changing inspection intervals for XI.S6: Structures Monitoring.
An IR point that the cited reference RG 1.16014 does not provide inspection intervals but talks about structural inspections that are commensurate with the safety significance of the components. The IR added that by using the same basis in RG 1.160, there are non-safety significant structures that are in-scope for license renewal under 54.4(a)(2)15, where a 10-year interval is more appropriate (rather than the guidance recommended 5-year). The staff clarified the basis of the 5-year interval and indicated the IRs feedback would be considered for updating guidance.
Public comment 31-002 relates to the clarification of GALL-SLR Vol. 1, Item II.A1.CP-32, aging effect/mechanism loss of strength due to leaching of calcium hydroxide and carbonation, with a recommendation to change the "and to or. The staff clarified that the loss of strength can be due to leaching of calcium hydroxide, or carbonation, or a combination of both.
14 U.S. NRC, Regulatory Guide 1.160, Revision 4, Monitoring the Effectiveness of Maintenance At Nuclear Power Plants, August, 2018, (ML18220B281).
15 10 CFR Part 54, Requirements for Renewal of Operating Licenses For Nuclear Power Plants.
8 Public comment 31-003 relates to the clarification of GALL-SLR Vol. 1, Item II.A1.CP-32 and the staff confirmed that the environment/aging combination is water-flowing.
Public comment 31-006 relates to the clarification of GALL-SLR Vol. 1, Item III.A4.TP-305, requesting clarification of associated containment internal structures considered as exterior above and below-grade inaccessible areas, which containment internal structures are exposed to water-flowing environments, and why containment foundation is included when it appears to be addressed by other items/tables. An IR cited an example on fire protection headers and stated the configuration may not fit with the scope AMR item. The staff clarified that plant specific configurations are to be considered and may likely result in the AMR item being not applicable.
Public comment 31-007 relates to the clarification of GALL-SLR Vol. 1, requesting clarification on why the environment is Air - indoor uncontrolled, instead of Air-indoor uncontrolled, neutron flux. The staffs position is that restricting the environment to neutrons will mask potential cumulative/combined aging effects on reactor vessel steel structural supports due to other environments, e.g., thermal, boric acid, etc.
Public comment 31-018 relates to the proposed removal of guidance related to cracking of high-strength bolting from various AMPs (XI.M18, XI.S1, XI.S3, XI.S6), as there is no license renewal OE in over 30 years on this degradation, and documented degradation was due to installation of design errors, not an aging issues. The staff clarified that the licensee can provide plant specific justification to opt out of the guidance. The feedback was noted by the NRC staff and they indicated the feedback would be considered for updating guidance.
Public comment 32-093 related to removing the requirement for a level control alarm at central location or control room in XI.E3A, XI.E3B, and XI.E3C. An IR indicated that it is not typical to put the alarm in the operator control room, but to pass alarms to the appropriate system owner or engineering station, and that this should meet the intent of the guidance.
The feedback was noted by the NRC staff and they indicated the feedback would be considered for updating guidance.
The NRC staff clarified that the staffs disposition of all public comments would be in a new Appendix C of the GALL-SLR, Vol. 2, Revision 1. The staffs disposition will include a summary of the public comment, a response, and an overview of any resulting changes to the guidance, if applicable.
For closing remarks, IRs expressed the importance of the decisions that are made on this guidance update as there are significant impacts to future subsequent license renewal applications. It was added that is worth investing the time with further dialogue, considering of comments and feedback, and having dedicated public meetings on select complex topics and AMPs.
Closing remarks by the NRC staff emphasized the importance of industry and public participation and comments on the guidance update process. The staff recapped schedule milestones going forward.