05000352/LER-2025-001, Bypass Leakage on the B Train of Standby Gas Treatment System HEPA Filters Exceeded Technical Specification Value
| ML25111A262 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 04/21/2025 |
| From: | Gillin M Constellation Energy Generation |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| LG-25-081 LER-2025-001-00 | |
| Download: ML25111A262 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3522025001R00 - NRC Website | |
text
10 CFR 50.73 LG-25-081 April 21, 2025 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 2025-001-00 Bypass Leakage on the B Train of Standby Gas Treatment System HEPA Filters Exceeded Technical Specification Value 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 Generation, LLC cc: Administrator Region I, USNRC USNRC Senior Resident Inspector, Limerick Generating Station Gillin, Michael F.
Digitally signed by Gillin, Michael F.
Date: 2025.04.21 17:39:22 -04'00'
=~ Constellation.
NRC FORM 366 (04-02-2024)
U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block)
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 04/30/2027
- 1. Facility Name 052 050
- 2. Docket Number
- 3. Page 1 OF
- 4. Title
- 5. Event Date Month Day Year
- 6. LER Number Year Sequential Number Revision No.
- 7. Report Date Month Day Year
- 8. Other Facilities Involved Facility Name Facility Name Docket Number Docket Number
- 9. Operating Mode
- 10. Power Level 050 052
Month Day Year Limerick Generating Station Unit 1
352 3
Bypass Leakage on the B Train of Standby Gas Treatment System HEPA Filters Exceeded Technical Specification Value 02 19 2025 2025 001 00 04 21 2025 Limerick Unit 2 353 OPCON 1 100
Jordan Rajan 610-718-3400 A
BH FLT A220 Yes
16. Abstract (Limit to 1326 spaces, i.e., approximately 13 single-spaced typewritten lines)
On February 19, 2025, at 08:40 the B USain of Standby Gas Treatment System (SGTS) was removed from service to test the charcoal adsorber and High-Efficiency Particulate Air (HEPA) filter banks. The test identified the as-found leakage for the upstream and downstream HEPA filter banks exceeded the Technical Specification (TS) leakage allowance. The HEPA filters were replaced, and the system was satisfactorJMy retested. This condition was reportable per 10 CFR 50.73(a)(2)(i)(B).
The BUSBJOPG SGTS was previously tested on March 19, 2020, and the as-found leakage was elevated. Since the leakage was close to the TS acceptance criteria, the issue was entered into the corrective action process. The HEPA filters exceeded the leakage criteria CFDBVTF&OHJOFFSJOHEJEOPUFOTVSFNBJOUFOBODFXBTTDIFEVMFEBOEFYFDVUFEQSJPSUPFYDFFEJOHUIF54
MJNJU. An action to perform post trending analysis will be added to the Surveillance Test package to ensure the filters do not exceed the TS leakage criteria before the next scheduled performance.
l~*"'""**,.\\
..-.,i,,,
T<o{-
I Page of
- 3. LER NUMBER YEAR SEQUENTIAL NUMBER REV NO.
052 050
Safety Consequence
There was no actual safety consequence associated with this event. The HEPA filter banks are conservatively credited with an efficiency of 99.0 percent. The as-found bypass leakage is bounded by the Alternate Source Term (AST) assumed SGTS HEPA filter bank efficiency. The B train of SGTS filter train was available to perform its design basis functions during the period where the upstream and downstream HEPA filter bypass leakage percentages exceeded the Technical Specification limits. This event is not a safety system functional failure.
Cause of the Event
The HEPA filters failed because Engineering did not ensure maintenance was scheduled and executed prior to exceeding the TS limit.
Corrective Actions Completed The HEPA filters were replaced on the B train of SGTS, and the test was re-performed verifying the in-place penetration and leakage testing of the HEPA filter banks met the TS surveillance requirements.
Corrective Actions Planned v
Review open deficiencies on TS equipment that could result in equipment inoperability to ensure the actions to addressequipment deficiencies are properly scheduled.
v Add a task to the Surveillance Test work packages that perform Charcoal/HEPA testing for TS trains to perform posttesting trending analysis to ensure that the Charcoal/HEPA filters are projected not to exceed the TS leakage criteriabefore the next scheduled performance.
Previous Similar Occurrences There have been no previous similar licensee event reports in the past ten years.
Component Data System: BH (Emergency/Standby Gas Treatment System)
Component: FLT (Filter)
Component Number:
v
%)8SVWUHDP+(3$ILOWHUEDQN v
%)'RZQVWUHDP+(3$ILOWHUEDQN 0DQXIDFWXUHU $ $$),QWHUQDWLRQDO
3 3
Limerick Generating Station Unit 1 352 2025 001 00
/¥,..,,.,
~
g
\\
i
....... +.
0~
I I~
I I I I D