ENS 57743
ENS Event | |
|---|---|
03:15 Apr 12, 2025 | |
| Title | Invalid Specified System Actuation |
| Event Description | The following information was provided by the licensee via phone and email:
At 2315 EDT on April 11, 2025, the spare train of Unit 2 auxiliary feedwater (AFW), the turbine-driven AFW pump (TDAFWP), automatically started. At the time, Unit 2 was entering a refueling outage and had been shutdown to hot standby conditions. Sufficient makeup water to the steam generators was being supplied by the 'A' and 'B' trains of AFW, [both] motor-driven AFW pumps. Several hours before this automatic start, feed from all main feedwater pumps (MFWPs) and the TDAFWP had been secured. The TDAFWP automatically started during the alignment of Unit 2 balance-of-plant to support the outage. As part of the alignment, condenser vacuum for the '2A' MFWP was broken prior to the de-energization of the '2A' MFWP's turbine trip bus. Even though the '2A' MFWP was incapable of providing any main feedwater flow, the order in which these two events were performed appeared to the protective circuitry as a low-vacuum trip of the '2A' MWFP, and thus a loss of all MFWPs. The loss of all MFWPs is an automatic start signal to the TDAFWP. This report is being made under 10 CFR 50.73(a)(2)(iv)(A) as an event that resulted in an invalid actuation of the Unit 2 TDAFWP. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector was notified of the event. |
| Where | |
|---|---|
Watts Bar  Tennessee (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1307.58 h54.483 days <br />7.783 weeks <br />1.791 months <br />) | |
| Opened: | Daniel Hudson 14:50 Jun 5, 2025 |
| NRC Officer: | Karen Cotton |
| Last Updated: | Jun 5, 2025 |
| 57743 - NRC Website
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WEEKMONTHYEARENS 577432025-04-12T03:15:00012 April 2025 03:15:00
[Table view]10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation ENS 573362024-08-02T01:27:0002 August 2024 01:27:00 10 CFR 50.73(a)(1), Submit an LER 60-DAY Notification of Invalid Specified System Actuation ENS 573242024-07-22T16:48:00022 July 2024 16:48:00 10 CFR 50.73(a)(1), Submit an LER 60-DAY Notification of Invalid Specified System Actuation ENS 570772024-02-16T02:24:00016 February 2024 02:24:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Emergency Diesel Generators ENS 562742022-11-24T21:21:00024 November 2022 21:21:00 10 CFR 50.73(a)(1), Submit an LER 60-DAY Optional Telephonic Notification of Invalid Actuation of Containment Ventilation Isolation Valves ENS 548702020-07-23T13:56:00023 July 2020 13:56:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification for Two Invalid Containment Ventilation Isolation Actuations ENS 542202019-07-26T14:03:00026 July 2019 14:03:00 10 CFR 50.73(a)(1), Submit an LER Invalid Containment Ventilation Isolation Actuation ENS 538402018-12-02T05:28:0002 December 2018 05:28:00 10 CFR 50.73(a)(1), Submit an LER Invalid Containment Ventilation Isolation Actuation ENS 527902017-04-28T09:00:00028 April 2017 09:00:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification for an Invalid Auxiliary Feedwater Actuation ENS 525392016-12-15T18:32:00015 December 2016 18:32:00 10 CFR 50.73(a)(1), Submit an LER 60 Day Optional Telephonic Notification for an Invalid Containment Ventilation Isolation Actuation ENS 520012016-04-14T18:06:00014 April 2016 18:06:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification for an Invalid Containment Vent Isolation Actuation ENS 511522015-04-15T16:07:00015 April 2015 16:07:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuations of the Containment Ventilation Isolation System ENS 510792015-03-17T17:06:00017 March 2015 17:06:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Auxiliary Feedwater System During Electrical Testing ENS 501332014-04-16T05:48:00016 April 2014 05:48:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification for Inadvertent Fast Start of Diesel Generator During Testing ENS 482042012-06-19T03:49:00019 June 2012 03:49:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Containment Ventilation Isolation ENS 441602008-02-23T04:00:00023 February 2008 04:00:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Verbal Notification of Invalid Specified System Actuation ENS 411832004-09-15T14:14:00015 September 2004 14:14:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Containment Vent Isolation Valve 2025-04-12T03:15:00 | |