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| Entered date | Event description | |
|---|---|---|
| ENS 56905 | 21 December 2023 12:29:00 | The following summary was provided by the licensee via phone and email: On December 21, 2023, VC Summer determined that the original equipment manufacturer of its Emergency Diesel Generator (EDG) did not provide adequate documentation for an exception to ASME Code, Section III, Class 3 for the on-skid EDG fuel oil system. Specifically, the on-skid fuel oil threaded piping design used a code-allowed exception without providing adequate evaluation documentation supporting threaded Schedule 40 piping. On November 2, 2022, the 'A' EDG fuel oil piping failed during routine testing, requiring it to be declared inoperable until repairs were implemented. The NRC Senior Resident Inspector has been notified. Corrective actions: VC Summer has compensatory measures in place and is scheduled to implement a modification during the first quarter of 2024. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: In addition to VC Summer, it was discussed via phone that Farley has a similar design for its on-skid EDG fuel oil system and potentially might be affected by this Part 21 report. No other sites have been discussed at this time. The EDG manufacturer is: Fairbanks-Morse Corp. EDG Model: Colt-Pielstick 12-Cylinder PC-2.2 VC Summer POC for additional information: Justin Bouknight, Licensing Engineer, (803) 941-9828, justin.bouknight@dominionenergy.com. |
| ENS 56919 | 10 January 2024 08:18:00 | The following information was provided by the licensee via email and phone call: On January 9, 2024, VC Summer Nuclear Station (VCSNS) determined a manufacturing defect affecting a control power circuit monitor (CP1) relay on its 'B' emergency diesel generator (EDG) was reportable under Part 21. On November 12, 2021, the 'B' EDG was rendered inoperable when its CP1 relay de-energized due to mechanical binding of the magnet carrier assembly. The binding was caused by a manufacturing defect that allowed heat-induced shrinkage to reduce the clearance between the magnet carrier and adjacent coil housing and base, preventing it from moving freely. VCSNS replaced the affected relay and restored operability of its 'B' EDG. Manufacturer/Model: Eaton-Cutler Hammer D26MRD30A1 A written notification in accordance with 10 CFR 21.21(d)(3)(ii) will be provided within 30 days. The NRC Senior Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The plant has notified the manufacturer. It is not known if any other plants are affected by this defect. |
| ENS 55808 | 30 March 2022 09:43:00 | The following information was provided by the licensee via fax or email: This is a non-emergency notification required by 10 CFR 21.21(d)(3)(i). A written notification in accordance with 10 CFR 21.21(d)(3)(ii) will be provided within 30 days. On June 22, 2021, VC Summer Nuclear Station (VCSNS) received information indicating that a poppet seal failure in the Feedwater Isolation Valve (FWIV) 'B' control block was due to laminations in the Viton material. The failure occurred on May 12, 2021 and was captured in the corrective action program as CR-21-01263. VCSNS completed a Substantial Safety Hazard Evaluation and determined that the laminations in VCSNS poppet seal lots 7064051 and 7081558 constituted a substantial safety hazard. The FWIV poppet seals are responsible for retaining and directing pressurized air to each side of the FWIV actuator for repositioning and maintaining FWIV position in both the open and closed positions. The NRC Senior Resident Inspector has been notified. |
| ENS 56920 | 10 January 2024 08:18:00 | The following information was provided by the licensee via email and phone call: On January 9, 2024, VC Summer Nuclear Station (VCSNS) determined a manufacturing defect affecting a field flash contactor (K2) relay on its 'B' emergency diesel generator (EDG) was reportable under Part 21. During testing on May 5, 2021, the 'B' EDG was rendered inoperable when its K2 relay coil switch exhibited intermittent binding due to insufficient clearances of the switch actuator from the protective case and plastic switch molding. The inadequate clearances resulted in accelerated loss of graphite lubrication at these locations, which led to mechanical binding. VCSNS replaced the affected relay and restored operability of its 'B' EDG. Manufacturer/Model: Gould F10NOCLD1 DC coil switch A written notification in accordance with 10 CFR 21.21(d)(3)(ii) will be provided within 30 days. The NRC Senior Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The licensee did not notify the intellectual property owner because the manufacturer is no longer operating or in business. They are not aware of other plants that utilize this coil switch. |
| ENS 49253 | 9 August 2013 08:21:00 | A contractor supervisor tested positive for alcohol on a follow-up fitness for duty screening. The individual's construction site access was revoked. The Unit 2/3 Resident Inspector has been notified. |