05000395/LER-2024-003, Common Cause Inoperability of Engineered Safety Features
| ML24323A154 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 11/18/2024 |
| From: | Denise Edwards Dominion Energy South Carolina |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 24-340 LER 2024-003-00 | |
| Download: ML24323A154 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 3952024003R00 - 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 November 18, 2024 U.S. Nuclear Regulatory Commission Washington, DC 20555 Dominion Energye Serial No.: 24-340 VCS-LIC/JB RO Docket No. 50-395 License No. NPF-12 DOMINION ENERGY SOUTH CAROLINA, INC. (DESC)
VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1 LICENSEE EVENT REPORT 2024-003-00 COMMON CAUSE INOPERABILITY OF ENGINEERED SAFETY FEATURES Dominion Energy South Carolina, Inc. hereby submits Licensee Event Report (LER) 2024-003-00, for VCSNS. Both trains of Engineered Safety Features located in the Control Building were conservatively declared inoperable on September 17, 2024, due to a degraded steam propagation barrier door.
This event was documented in Condition Report CR1269095 in the VCSNS Corrective Action Program. CR1269095 is still open, and a supplemental report is planned by January 31, 2025.
Should you have any questions, please call Mr. Justin Bouknight at (803) 941-9828.
Sincerely, ouglas J. Edwards Director, Nuclear Station Safety & Licensing V.C. Summer Nuclear Station Enclosure Commitments contained in this letter: None cc:
G. J. Lindamood - Santee Cooper L. Dudes - NRC Region II G. Miller-NRC Project Mgr.
NRC Resident Inspector Marsh USA, Inc.
Abstract
V.C. Summer Nuclear Station 395 2
COMMON CAUSE INOPERABILITY OF ENGINEERED SAFETY FEATURES 09 17 2024 2024 003 00 11 18 2024 1
100 Justin Bouknight, Licensing Engineer 803-941-9828 NA DR Y
1 31 2025 On September 17, 2024, at 2005 ET, V.C. Summer Nuclear Station (VCSNS) identified that a Control Building Door (DRCB/501) was closed, but not latching properly. DRCB/501 is a steam propagation barrier (SPB) located on the 463' elevation, between the Turbine Building and Control Building. Both trains of engineered safety features (ESF) in the Control Building were conservatively declared inoperable due to the degraded SPB.
At 2032 ET, DRCB/501 was repaired, restoring OPERABILITY of the effected ESF equipment located in the Control Building.
Reactor power remained at 100% throughout the event.
This event is being reported in accordance with 10 CFR 50.73(a)(2)(vii). Page of
- 3. LER NUMBER YEAR SEQUENTIAL NUMBER REV NO.
052 050 1.0 DESCRIPTION OF THE EVENT On September 17, 2024, at 2005 ET, both trains of engineered safety features (ESF) located in the V.C. Summer Nuclear Station (VCSNS) Control Building were declared inoperable. The equipment was conservatively determined to be inoperable due to degradation of a steam propagation barrier (SPB).
VCSNS identified that Door DRCB/501, located between the Control Building and Turbine Building on the 463 elevation, was closed, but not latching properly. DRCB/501 is a SPB credited to mitigate postulated high energy line breaks in the Turbine Building and is relied upon to support OPERABILITY of ESF equipment located in the Control Building.
At 2032 ET, DRCB/501 was repaired and confirmed to latch properly. The ESF equipment reliant upon its SPB function was restored to OPERABLE status upon repair of the door latch.
Reactor power remained at 100% throughout the event. This event is being reported in accordance with 10 CFR 50.73(a)
(2)(vii).
2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS
Without a functional SPB between the Control Building and Turbine Building, ESF equipment in the Control Building could not be relied upon to mitigate the consequences of a postulated high energy line break in the Turbine Building.
3.0 CAUSE OF THE EVENT
This event was documented in Condition Report (CR) CR1269095 under the VCSNS Corrective Action Program (CAP).
The CR is still open and a supplemental report will be provided by January 31, 2025.
4.0 CORRECTIVE ACTIONS
The DRCB/501 latch was repaired and its supported ESF equipment was declared OPERABLE.
CR1269095 is still open and any further required corrective actions will be provided in a supplemental report.
5.0 SIMILAR EVENTS
No similar events were identified within the last three years.
2 2
V.C. Summer Nuclear Station 395 2024 003 00