05000389/LER-2024-002-01, Safety Injection Tank Vent Through Wall Leakage
| ML24194A149 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 07/11/2024 |
| From: | Rasmus P Florida Power & Light Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-2024-117 LER 2024-002-01 | |
| Download: ML24194A149 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded |
| 3892024002R01 - NRC Website | |
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U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Re:
St. Lucie Unit 2 Docket No. 50-389 Reportable Event: 2024-02-01 Date of Event: January 3, 2024 Safety Injection Tank Vent Through Wall Leakage July 11, 2024 L-2024-117 10 CFR 50.73 The attached Licensee Event Report, 2024-02-01, is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.
Should you have any questions regarding this submission, please contact Mr. Kenneth Mack, Fleet Licensing Manager, at 561-904-3635.
This letter contains no new or modified regulatory commitments.
Sincerely, Paul Rasmus General Manager - Regulatory Affairs - Nuclear Fleet Florida Power & Light Company Attachment cc:
St. Lucie NRC Senior Resident Inspector St. Lucie Station NRC Program Manager Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957
Abstract
This LER revision supersedes LER 2024-02-00 in its entirety.
On January 3, 2024, while in Mode 3, it was determined that the Reactor Coolant Pressure Boundary (RCPB) had a through wall flaw with Safety Injection Tank (SIT) leakage. The leakage was coming from the welded connection of a vent valve for SIT 2A2 outlet valve piping segment Sl-227. The cause of the leak was microcracks in weld material from a December 16, 2023, repair.
This leak resulted in the Unit being in a Degraded Condition. There were no Systems, Structures, or Components that were inoperable at the start of the event that contributed to the event. This event is being reported pursuant of 10 CFR 50.73(a)(2)
(ii)(A), Degraded Condition.
Description of Event
- 2. DOCKET NUMBER
- 3. LER NUMBER I
00389 D
NUMBER NO.
I YEAR SEQUENTIAL REV
~-I 02 1-0 On January 3, 2024, while in Mode 3, it was determined that the Reactor Coolant Pressure Boundary (RCPB) had a through wall flaw with Safety Injection Tank (SIT) leakage. The leakage was coming from the welded connection of a vent valve for SIT 2A2 outlet valve piping segment Sl-227. This leak resulted in the Unit being in a Degraded Condition. There were no Systems, Structures, or Components that were inoperable at the start of the event that contributed to the event.
Cause of Event
The leak was caused by microcracks in weld material from a December 16, 2023, repair. These microcracks occurred during solidification of the weld material.
Safety Significance
This event did not prevent any safety systems from performing their safety related functions based on the minimal amount of leakage identified.
This Licensee Event Report is being reported pursuant of 10 CFR 50.73(a)(2)(ii)(A), Degraded Condition.
This event did not result in a Safety System Functional Failure.
Corrective Actions
Repairs to Sl-227 were completed on January 5, 2024.
Similar Events
A review of events over the past 5 years identified one previous event that involved a similar underlying cause of the event reported under this Licensee Event Report. This event is documented in LER 2024-01, Safety Injection Tank Vent Line Through Wall Leakage, dated February 13, 2024. The cause of that event was stresses resulting fatigue crack initiation and propagation. Page 2
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