05000335/LER-2025-001, Safety Injection Tank Above Technical Specification Limits
| ML25085A185 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 03/26/2025 |
| From: | Mack K Florida Power & Light Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-2025-062 LER 2025-001-00 | |
| Download: ML25085A185 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3352025001R00 - NRC Website | |
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U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Re:
St. Lucie Unit 1 Docket No. 50-335 Renewed Facility Operating License No. DPR-67 Reportable Event: 2025-01-00 Date of Event: January 27, 2025 Safety Injection Tank Above Technical Specifications Limit March 26, 2025 L-2025-062 10 CFR 50.73 The attached Licensee Event Report, 2025-01, 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 Maribel Valdez, Fleet Licensing Manager, at 561-904-5164.
This letter contains no new or modified regulatory commitments.
Sincerely, Kenneth A. Mack Director, Licensing and Regulatory Compliance Florida Power & Light Company Attachment cc:
USNRC Regional Administrator, Region II USNRC Project Manager, St. Lucie Power Nuclear Plant USNRC Senior Resident Inspector, St. Lucie Power Nuclear Plant Mr. Clark Eldredge, Florida Department of Health Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957
Abstract
On January 27, 2025, at Unit 1, 1A1 Safety Injection Tank (SIT) indicated level became erratic, rendering 1A1 SIT inoperable. Instrumentation and Control (l&C) technicians replaced a circuit card for the level indicator. After calibration, the 1A 1 SIT level indicated 100.8% which is above the Technical Specification Surveillance Requirement Limit (1170 ft3) for SIT volume. 1A 1 SIT water volume was then reduced from 100.8% to 94.2% indicated level which is within the Technical Specification (TS) volume limit of 1090 -1170ft3. As level was being lowered, the High-High level alarm cleared and 1A1 SIT was declared operable. The 1A1 SIT level transmitter had a failed circuity card causing inaccurate indication on A-train Level Indication Alarm (L 1A-3321). 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)(i)(B), Operation or Condition Prohibited by TS.
Description of Event
Eslimaled
- 2. DOCKET NUMBER
- 3. LER NUMBER I
335 D
NUMBER NO.
I YEAR SEQUENTIAL REV
~-I 01 1-0 On January 27, 2025, at Unit 1, 1A1 SIT indicated level became erratic, rendering 1A1 SIT inoperable. l&C technicians replaced a circuit card for the level indicator. After calibration, the 1A1 SIT level indicated 100.8% which is above the Technical Specification Surveillance Requirement Limit (1170 ft3) for SIT volume. 1A1 SIT water volume was then reduced from 100.8% to 94.2% indicated level which is within the TS volume limit of 1090 - 1170 ft3
- As level was being lowered, the High-High level alarm cleared and 1A1 SIT was declared operable. Prior to the event on January 8, 2025, a High-High level alarm was received while filling 1A1 SIT. The indicated level, as read from LIA-3321, appeared within the normal operating band. The High-High level alarm was indicated at a lower-than-expected level, due to the Limit Switch (LS-3323) being faulted. Therefore, the High-High level alarm remained locked in until the event occurred on January 27.
Cause of Event
The 1A1 SIT LIA-3321 circuit card failed causing inaccurate SIT level indication.
Safety Significance
This event resulted in an entry into Technical Specification Action Statement (TSAS) 3.5.1, Action B (24-hour shutdown) and an NRC reportable event.
The Licensee Event Report is being reported pursuant of 10 CFR 50.73 (a)(2)(i)(B), Operation or Condition Prohibited by TS.
This event did not result in a Safety System Functional Failure.
Corrective Actions
Corrected by the replacement and calibration of the circuit card.
Similar Events
A review of events over the past 5 years did not identify any similar events with the same cause as this event. Page 2
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