ENS Event | |
|---|---|
20:02 Nov 14, 2025 | |
| Title | Unusual Event - Loss of All Offsite Power to Vital Busses |
| Event Description | The following information was provided by the licensee via phone:
On November 14, 2025, at 1351 CST, while in a system outage window, for the reserve auxiliary transformer 'B' bus work inspections, the emergency reserve auxiliary transformer tripped. This resulted in the loss of offsite power to all vital busses. At 1402 CST, a notice of unusual event was declared (MU.1) due to the loss of all offsite power to vital busses. All three emergency diesel generators actuated and energized the vital busses. Notified DHS SWO, DOE Ops Center, FEMA Operations Center, FEMA NWC, CWMD Watch Desk, HHS Ops Center, CISA Central Watch Officer, USDA Ops Center, EPA EOC, FDA EOC (email), DHS Nuclear SSA (email), DHS NRCC THD Desk (email), FEMA NRCC SASC (email), and FERC Reliability Monitoring Center (email).
The following update is a summary of information provided by the licensee via phone and email: On November 16, 2025, at 0500 CST, the Unusual Event was terminated. All offsite electrical power has been restored, and the plant is in a normal electrical lineup. The NRC Resident Inspector was notified. Notified R3RA (Geissner), NRR (Groom), NSIR (Williams), R3DO (Ziolkowski), NRR EO (Mckenna), IR MOC (Grant), R3PAO (Mitlyng), R3DRSS (Heck). Notified DHS SWO, DOE Ops Center, FEMA Operations Center, FEMA NWC, CWMD Watch Desk, HHS Ops Center, CISA Central Watch Officer, USDA Ops Center, EPA EOC, FDA EOC (email), DHS Nuclear SSA (email), DHS NRCC THD Desk (email), FEMA NRCC SASC (email), and FERC Reliability Monitoring Center (email). |
| Where | |
|---|---|
Clinton  Illinois (NRC Region 3) | |
| Reporting | |
| Emergency class: | Unusual Event |
| 10 CFR 50.72(a) (1) (i), Emergency Class Declaration | |
| Time - Person (Reporting Time:+-4.03 h-0.168 days <br />-0.024 weeks <br />-0.00552 months <br />) | |
| Opened: | Cory Popp 16:00 Nov 14, 2025 |
| NRC Officer: | Sam Colvard |
| Last Updated: | Nov 16, 2025 |
| 58038 - NRC Website
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WEEKMONTHYEARENS 580382025-11-14T20:02:00014 November 2025 20:02:00
[Table view]10 CFR 50.72(a)(1)(i), Emergency Class Declaration Unusual Event - Loss of All Offsite Power to Vital Busses ENS 475442011-12-21T23:57:00021 December 2011 23:57:00 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Unusual Event - Hydrogen Leak in Turbine Building 2025-11-14T20:02:00 | |