ENS 58104
ENS Event | |
|---|---|
14:15 Nov 2, 2025 | |
| Title | Invalid Specified System Actuation |
| Event Description | The following information was provided by the licensee via phone and email:
On November 2, 2025, at 0915 EST, and on November 3, 2025 at 0203 EST, while [Hatch] Unit 1 was at 100-percent power, the normal supply breaker from the `1D' 600V switchgear to the 120/208V essential transformer `1C' tripped on overcurrent due to a ground resulting in the loss of the `1B' essential bus and the `1B' instrument bus. The loss of power impacted the logic of the primary and secondary containment isolation systems resulting in the invalid actuation of containment isolation valves (CIVs) in multiple systems. The ground within the `1D' 600V switchgear was cleared by racking [out] the associated breaker and by replacing a degraded wire. A future action includes performing a detailed cubical and bus bar inspection of the `1D' 600V switchgear. This event is reportable per 10 CFR 50.73(a)(2)(iv)(A) because it was not part of a pre-planned sequence and resulted in the invalid, partial actuation of CIVs in both the primary containment and secondary containment systems, with all systems responding normally. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| Where | |
|---|---|
| Hatch Georgia (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1412.57 h58.857 days <br />8.408 weeks <br />1.935 months <br />) | |
| Opened: | Hugh Garrett Crosby 10:49 Dec 31, 2025 |
| NRC Officer: | Ernest West |
| Last Updated: | Dec 31, 2025 |
| 58104 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 581042025-11-02T14:15:0002 November 2025 14:15:00
[Table view]10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation ENS 576912025-03-14T19:23:00014 March 2025 19:23:00 10 CFR 50.73(a)(1), Submit an LER 60-DAY Optional Telephonic Notification for an Invalid Containment Isolation ENS 568972023-11-02T01:11:0002 November 2023 01:11:00 10 CFR 50.73(a)(1), Submit an LER 60 Day Notification for an Invalid Specified System Actuation ENS 551882021-02-18T03:20:00018 February 2021 03:20:00 10 CFR 50.73(a)(1), Submit an LER Automatic Actuation of Group 2 Containment Isolation Logic ENS 551872021-02-13T03:23:00013 February 2021 03:23:00 10 CFR 50.73(a)(1), Submit an LER Automatic Actuation of Group I Containment Isolation Logic ENS 538172018-11-12T05:00:00012 November 2018 05:00:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation ENS 528182017-04-27T04:29:00027 April 2017 04:29:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation Due to Failed Relay ENS 528032017-04-17T15:20:00017 April 2017 15:20:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification of Invalid Specified System Actuation ENS 526852017-02-17T15:21:00017 February 2017 15:21:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification of Invalid Specified System Actuation ENS 496412013-10-21T09:19:00021 October 2013 09:19:00 10 CFR 50.73(a)(1), Submit an LER 60 Optional Report - Invalid Partial Reactor Protection System Actuation ENS 490552013-03-24T14:09:00024 March 2013 14:09:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Hpci Suction Valves ENS 487212012-12-08T06:16:0008 December 2012 06:16:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephone Notification of Invalid System Actuation ENS 485652012-10-08T22:09:0008 October 2012 22:09:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification of Invalid System Actuation ENS 483702012-08-06T01:25:0006 August 2012 01:25:00 10 CFR 50.73(a)(1), Submit an LER Rps Sub-Component Failure Caused Half Scram with Group 2 Pciv Actuation ENS 478592012-02-25T05:38:00025 February 2012 05:38:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Standby Gas Treatment Secondary Containment Isolation Valves (Scivs) ENS 473372011-08-12T09:03:00012 August 2011 09:03:00 10 CFR 50.73(a)(1), Submit an LER 60 Day Optional Telephone Notification for an Invalid Specified System Actuation ENS 461152010-05-29T12:49:00029 May 2010 12:49:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Primary Containment Isolation Valves Due to a Faulty Transistor ENS 459812010-04-16T23:15:00016 April 2010 23:15:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation ENS 458352010-02-23T14:50:00023 February 2010 14:50:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Standby Gas Treatment System ENS 432762007-02-25T08:58:00025 February 2007 08:58:00 10 CFR 50.73(a)(1), Submit an LER Invalid Secondary Containment Isolation ENS 424922006-02-28T06:50:00028 February 2006 06:50:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation Due to Work Instruction Error ENS 421102005-10-07T15:37:0007 October 2005 15:37:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation ENS 415902005-02-19T10:50:00019 February 2005 10:50:00 10 CFR 50.73(a)(1), Submit an LER 60 Day Invalid Actuation of System Report. 2025-03-14T19:23:00 | |