05000395/LER-2025-003, V.C Summer Nuclear Station, Unit 1, Potential Condition Prohibited by Technical Specifications
| ML25290A333 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 10/17/2025 |
| From: | Jenkins B South Carolina Electric & Gas Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| VCS-LIC/JB RO, 25-252 LER 2025-003-00 | |
| Download: ML25290A333 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3952025003R00 - NRC Website | |
text
Dominion Energy South Carolina, Inc Virgil C. Summer Nuclear Station Bradham Boulevard & Highway 215, Jenkinsville, SC 29065 Mailing Address:
P.O. Box 88, Jenkinsville, SC 29065 DominionEnergy.com Document Control Desk October 17, 2025 U.S. Nuclear Regulatory Commission Washington, DC 20555 DOMINION ENERGY SOUTH CAROLINA, INC.
fi. Dominion ii a,, Energy~
Serial No.: 25-252 VCS-LIC/JB RO Docket No. 50-395 License No. NPF-12 VIRGIL C. SUMMER NUCLEAR STATION UNIT 1 {VCSNS)
LICENSEE EVENT REPORT 2025-003-00 POTENTIAL CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS Dominion Energy South Carolina, Inc. hereby submits VCSNS Licensee Event Report (LER) 2025-003-00. This report documents inoperability of the Turbine Driven Feedwater Pump (TDEFP) identified during surveillance testing on August 19, 2025.
Evaluation to determine the cause of the TDEFP trip is ongoing and this report will be supplemented or retracted, pending conclusion of that evaluation.
This event is being reported under 10 CFR 50.73(a)(2)(i)(B), as a potential condition prohibited by Technical Specifications.
Should you have any questions, please call Mr. Justin Bouknight at (803) 941-9828.
Sincerely, Beth Jenkins Site Vice President V.C. Summer Nuclear Station Enclosure Commitments contained in this letter: None cc:
G. J. Lindamood - Santee Cooper J. Lara - NRC Region II G. Miller - NRC Project Mgr.
NRC Resident Inspector Marsh USA, Inc.
Abstract
On August 19, 2025, during performance of a quarterly surveillance, the Turbine Driven Emergency Feedwater Pump tripped resulting in the pump being declared inoperable. Troubleshooting and Failure Mode Analysis were performed to determine likely causes and appropriate repairs. Following repairs, the Turbine Driven Emergency Feedwater Pump successfully completed the quarterly surveillance test and was declared operable on August 21, 2025.
Pending results of the cause evaluation, this event is being reported as a potential condition prohibited by Technical Specifications in accordance with 10 CFR 50.73(a)(2)(i)(B).
1.0 DESCRIPTION OF THE EVENT I
- 2. DOCKET NUMBER
- 3. LER NUMBER I VEAR SEQUENTIAL REV NUMBER NO.
395
- l202sl -I 1-0 003 On August 19, 2025, at 11 :50 Eastern Time, VC Summer Nuclear Station (VCSNS) entered Technical Specification (TS) 3.7.1.2, Action (a), initiating a planned 72-hour action statement to perform quarterly surveillance testing.
During performance of Surveillance Test Procedure STP-220.002, "Turbine Driven Emergency Feedwater Pump and Valve Test," the Turbine Driven Emergency Feedwater Pump (TDEFP) failed to reach operating speed on the initial start attempt. The pump was subsequently reset, and a second start attempt was successful with no abnormal conditions.
A Failure Mode Analysis (FMA) was conducted, including inspection of the TDEFP and its associated Overspeed Trip Device (OTD). The analysis concluded that the most probable cause of the failure related to engagement of the OTD tappet nut.
Corrective actions included adjustment of the tappet nut orientation to ensure proper engagement with the trip lever and the emergency hold-down bracket. Following these adjustments and successful completion of STP-220.002, the TDEFP was declared operable on August 21, 2025.
A Level of Effort (LEE) evaluation is currently in progress in accordance with Dominion Energy Nuclear Fleet standards.
The LEE will determine the most likely cause of the failure, identify appropriate corrective actions, and assess whether firm evidence exists of inoperability prior to August 19, 2025.
Pending the outcome of the LEE, this event is conservatively being reported as a condition prohibited by Technical Specifications, in accordance with 10 CFR 50. 73(a)(2)(i)(B).
2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS There were no safety consequences or adverse implications resulting from the TDEFP inoperability. Certain postulated accident scenarios rely on the availability of the emergency feedwater system to provide water to the steam generators for the purpose of removing core decay heat during and after the postulated accident scenarios. The purpose of the TDEFP is to perform this function during loss of power scenarios, which would cause both motor-driven emergency feedwater pumps to be inoperable. Normal power to the station was maintained throughout the TDEFP inoperability period, so the safety consequences were negatable.
3.0 CAUSE OF THE EVENT
The cause of the event will be provided in a supplemental report, following conclusion of the Level of Effort Evaluation.
4.0 CORRECTIVE ACTIONS
I
- 2. DOCKET NUMBER
- 3. LER NUMBER I VEAR SEQUENTIAL REV NUMBER NO.
395
- l 202sl -I 1-0 003 Interim corrective actions included adjusting the tappet nut orientation to improve engagement with ODT components and completing the surveillance test to restore operability of the TDEFP and exit TS 3. 7.1.2, Action a. Additional corrective actions, if any, will be provided in a supplemental report, following conclusion of the Level of Effort Evaluation.
5.0 SIMILAR EVENTS
No similar events were identified within the last three years.
6.0 EQUIPMENT Turbine Driven Emergency Feedwater Pump Component Tag: TPP000S Manufacturer: Terry Model: GS-2 Page 3
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