05000352/LER-2024-001, Leakage for the Unit 1 `B Outboard Main Steam Isolation Valve Exceeded Technical Specification Limit
| ML24162A324 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 06/10/2024 |
| From: | Gillin M Constellation Energy Generation |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| LG-24-065 LER 2024-001-00 | |
| Download: ML24162A324 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3522024001R00 - NRC Website | |
text
~:.~ Constellation 10 CFR 50.73 LG-24-065 June 10, 2024 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 1 Renewed Facility Operating License No. NPF-39 NRC Docket No. 50-352 Subject: LER 2024-001-00 Unit 1 'B' Main Steam Isolation Valve Exceeded the Technical Specification Allowable Leak Rate In accordance with the requirements of 10 CFR 50.73(a)(2)(i)(B), Limerick Generating Station hereby submits the enclosed Licensee Event Report.
There are no commitments contained in this letter.
If you have any questions, please contact Jordan Rajan at (610) 718-3400.
Respectfully, Michael F. Gillin Vice President - Limerick Generating Station Constellation Energy Company, LLC cc: Administrator Region I, USNRC USNRC Senior Resident Inspector, Limerick Generating Station
Abstract
Limerick Generating Station Unit 1
352 3
Leakage for the Unit 1 `B' Outboard Main Steam Isolation Valve Exceeded Technical Specification Limit 04 09 2024 2024 001 00 06 10 2024 5
0
Jordan Rajan 610-718-3400 B
SB ISV A585 Yes
On April 9, 2024, during Local Leak Rate Testing (LLRT) conducted during the Unit 1 refueling outage (1R20), as-found leakage for the `B' Outboard Main Steam Isolation Valve (MSIV) HV-041-1F028B was 208.9 standard cubic feet per hour (scfh), which exceeded the Technical Specification (TS) 3.6.1.2.c limit of 100 scfh for individual MSIV leakage. The affected MSIV was declared inoperable, and the valve was disassembled to perform internal repairs.
The as-left leak rate following this maintenance was 1.7 scfh.
Based on the preliminary cause, there is evidence that the condition existed during the last operating cycle for longer than allowed by Technical Specification (TS) 3.6.3.a. This condition is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications.
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- 3. LER NUMBER YEAR SEQUENTIAL NUMBER REV NO.
052 050 Corrective Actions Completed Corrective maintenance was completed for HV-041-1F028 in accordance with station procedures. The as-left leak rate following this maintenance was 1.7 scfh, which is consistent with historical as left MSIV leak rates following inbody maintenance.
Corrective Actions Planned
Complete a corrective action program investigation to determine the cause of the LLRT failure and any required
corrective actions
Evaluate submitting a license amendment request to change the Limerick TS requirement for MSIV leakage from a
single valve leakage and total valve allowed leakage limit to a steam line leakage and total valve leakage limit consistent
with the requirements of NUREG-1433Standard Technical Specifications - General Electric BWR/4 Plants
Previous Similar Occurrences There have been no previous similar licensee event reports in the past ten years.
Component Data System: SB (Main/Reheat Steam System)
Component: ISV (Valve, Isolation)
Manufacturer: A585 (Attwood & Morrill Company, Inc.)
3 3
Limerick Generating Station Unit 1 352 2024 001 00
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