ML25321A393
| ML25321A393 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 12/05/2025 |
| From: | Audrey Klett NRC/NRR/DORL/LPL1 |
| To: | Constellation Energy Generation |
| Klett, AL | |
| References | |
| EPID L-2025-LRM 0128 | |
| Download: ML25321A393 (0) | |
Text
Enclosure December 5, 2025 LICENSEE:
Constellation Energy Generation, LLC FACILITY:
Limerick Generating Station (Limerick), Unit 1
SUBJECT:
SUMMARY
OF SEPTEMBER 29, 2025, PUBLIC OBSERVATION PREAPPLICATION MEETING WITH CONSTELLATION ENERGY GENERATION, LLC ON LOCAL LEAK RATE TESTING EXTENSION (EPID L-2025-LRM-0128)
On September 29, 2025, the U.S. Nuclear Regulatory Commission (NRC) staff held a virtual public observation meeting with Constellation Energy Generation, LLC (the licensee) to discuss the licensees plans to submit a license amendment request (LAR) and proposed alternative to allow a one-time extension of due dates for local leak rate testing (LLRT), or Type C testing, for four containment isolation valves. The meeting notice and agenda, dated September 19, 2025, are available in the NRCs Agencywide Documents Access and Management System (ADAMS) at Accession No. ML25262A068. The enclosure to this summary contains a list of meeting attendees. The licensees presentation slides are available in ADAMS at ML25265A018.
During the meeting, the licensee discussed that the LLRT extension is needed to support the installation of modifications for the digital modernization project (DMP) during the Limerick, Unit 1, Spring 2026 refueling outage. The licensee indicated that the DMP will require significant modifications during the Limerick, Unit 1, Spring 2026 outage and explained the challenges and risks associated with performing the required LLRT in addition to the DMP modifications during the upcoming outage. The licensee indicated that the LAR would modify technical specifications for the primary containment leakage rate test program to allow a one-time exception (until the Spring 2028 refueling outage) to the Type C testing specified in Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Appendix J for the four valves listed in the licensees presentation slides. The licensee indicated that the NRC previously authorized Alternative Request GVRR-8 (ML20280A757) that allows pressure isolation valve leakage (PIV) testing on an extended frequency pending satisfactory inservice testing (IST) leakage and Appendix J tests. The new proposed alternative would allow a one-time exception to Alternative Request GVRR-8 to defer resetting the test interval for three of the four valves that tested above administrative limits and are subject to the IST program. The licensee described the specific valves for which the extension is requested, recent and historical test results, and maintenance performed on the valves. The licensee plans to submit the requests under one cover letter in October 2025 and request NRCs review be complete by March 31, 2026.
The NRC staff asked the licensee for more information about the valves. The licensee responded that the HV-052-108 valve is a 12-inch power assisted core spray discharge check valve, HV-051-1F015B is a 12-inch Loop B residual heat removal (RHR) shutdown cooling injection Anchor Darling globe valve, HV-051-1F017B is a 12-inch Loop B RHR low pressure coolant injection (LPCI) Anchor Darling gate valve, and HV-051-1F027B is a 6-inch suppression pool spray Anchor Darling globe valve. The NRC staff asked if these valves have both Appendix J and IST leakage testing requirements and whether those tests are performed at the same or different times. The licensee indicated that the last valve discussed is part of the IST program but that it does not receive a PIV water leakage test (its not an ISTC-3630 valve, but it is an Appendix J valve). The tests are performed during the same outage, typically sequentially, but some activities may occur between tests.
The NRC staff asked the licensee how it included the leakage from the HV-052-108 valve that read off-scale in its combined Type B and Type C total leakage summation during the 2024 outage. The licensee discussed that the as-found minimum path is for the second barrier for all of the penetrations, which is the closed loop outside of containment, and that the licensee credits the fact that they had a satisfactory closed loop outside of containment for its minimum path. The licensee stated that for the maximum path coming out of an outage, it takes the as-left measured value that is shown in the 3rd column (in the table on slide 6) for all of those valves.
The licensee confirmed that it is deferring the maintenance or corrective action for HV-051-1F015B until the next outage.
The NRC staff noted that the licensee plans to request a change to the same technical specifications page as a LAR that is already under review but that the licensee is planning to denote the requested exceptions differently (i.e., as built-in text for LAR under review and a footnote for the planned LLRT LAR). The staff noted that this may be confusing. The licensee indicated that it would consider updating the LLRT LAR to be consistent with the ILRT LARs method of noting exceptions.
The staff noted that Alternative Request GVRR-8 was authorized under 10 CFR 50.55a(z)(1).
The licensee stated that it was planning to submit the proposed alternative under 10 CFR 50.55a(z)(2) as a hardship request because it would be difficult to perform the test. The licensee indicated that the configuration set-up for the DMP modifications and the LLRT would affect multiple trains of emergency core cooling system and require alternative controls outside of the control room. The licensee indicated that the proposed alternative would essentially be a temporary exception from Alternative Request GVRR-8. The NRC staff asked if its proposed alternative would be a separate request from Alternative Request GVRR-8 instead of a supplement to Alternative Request GVRR-8. The licensee indicated that it would be a separate request and that it would be modifying the one provision to leakage test the three valves in 4 years instead of 2 years and that all other IST testing would be performed in the spring 2026 outage. The NRC staff recommended that the request include trending data to support increasing the testing interval by 2 years and to clarify that the valves are PIVs rather than containment isolation valves (CIVs). The NRC staff also noted that the licensee should consider justifying its request as: (1) a relief request under 10 CFR 50.55a(f), (2) an acceptable level of quality and safety alternative request under 10 CFR 50.55a(z)(1), or (3) a hardship alternative request under 10 CFR 50.55a(z)(2). In that the NRC previously authorized Alternative Request GVRR-8, which overlaps with the planned request, the NRC staff suggested that the licensee address Alternative Request GVRR-8 in its planned request for the applicable valves.
The NRC staff asked questions about the valve testing results. The licensee stated that it performed a technical evaluation instead of a root cause evaluation for the valve testing failures and indicated that it would describe that information in its submittal. The licensee indicated that its testing strategy is to alternate divisions. The affected valves are Division B valves, which were deferred in 2018 (the B outage), but the 2020 outage was the COVID pandemic outage that deferred testing, so the licensee did not defer them in 2024. The staff asked if the last two valves had maintenance during the 2022 outage because it appears they failed their administrative limits in 2022. The licensee indicated that they were removed from the extended frequency. They were evaluated to be acceptable to be extended to the next outage, were tested in the 2024 outage and then underwent corrective maintenance in the 2024 outage.
The NRC staff did not make any regulatory decisions at the meeting. NRC staff statements at the meeting should not be interpreted as new or revised NRC positions that would result in backfitting, forward fitting, or impact issue finality. To support a constructive meeting, the staff may have offered guidance, identified NRC requirements, or provided additional information for consideration. The licensee indicated that it would address the NRC staff feedback in its submittal; however, the licensee is not required to consider NRC comments made during the meeting. Members of the public were not in attendance. Public Meeting Feedback forms were not received.
Please direct any inquiries to me at (301) 415-0489, or Audrey.Klett@nrc.gov.
/RA/
Audrey Klett, Senior Project Manager Plant Licensing Branch 1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-352
Enclosure:
List of Attendees cc: Listserv
Enclosure LIST OF ATTENDEES SEPTEMBER 29, 2025, MEETING WITH CONSTELLATION ENERGY GENERATION, LLC LIMERICK GENERATING STATION, UNIT 1 NRC Participants
- 1. Aaron Gallman
- 2. Audrey Klett
- 3. Brian Lee
- 5. Clint Ashley
- 8. Ian Tseng
- 9. Jay Robinson
- 10. Rob Atienza
- 11. Shao Lai
- 12. Stewart Bailey
- 13. Thomas Scarbrough Constellation Energy Generation, LLC Participants
- 1. Alexander Koshy
- 2. Brian Mast
- 3. John R George Jr
- 4. Kris T Singer
- 5. Laura Lynch
- 6. Lane T Oberembt
- 7. Marcellus R Ruff
- 8. Stephen L Deihm
- 9. Wendi E Para No members of the Public Identified.
ML25321A393 OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DSS/SCPB/BC NRR/DSS/STSB/BC NAME AKlett KEntz MValentin-Olmeda SMehta DATE 11/24/2025 11/19/2025 11/25/2025 12/01/2025 OFFICE NRR/DEX/EMIB/BC NRR/DEX/ESEB/BC NRR/DORL/LPL1/BC (A)
NRR/DORL/LPLX-X/PM NAME SBailey (TScarbrough for) ITseng UShoop AKlett DATE 12/02/2025 12/02/2025 12/05/2025 12/05/2025