ENS 57077
ENS Event | |
|---|---|
02:24 Feb 16, 2024 | |
| Title | Invalid Actuation of Emergency Diesel Generators |
| Event Description | The following information was provided by the licensee via email:
At 2224 EST on February 15, 2024, with both units 1 and 2 in Mode 1 at 100 percent power, an invalid start of the emergency diesel generator (EDG) system on 1A-A, 1B-B, and 2B-B EDGs occurred while removing clearances. The 2A-A EDG did not start because it was still under a clearance. The 1A-A, 1B-B, and 2B-B EDGs started and functioned successfully. The start signal for the 1A-A, 1B-B, and 2B-B EDGs was generated from the common emergency start of the 2A-A EDG. The signal was not from a loss of offsite power (LOOP) to any shutdown board or from any parameters that would initiate a safety injection (SI) signal, for which the EDG is designed to provide a design basis safety function. Also, the starts were not from intentional manual actuation. Starting the EDGs did not make them inoperable and each EDG was able to perform its design [basis] safety function. The common emergency start relay for each diesel is not safety related. It is an anticipatory and redundant circuit to start other EDGs in the event of a LOOP or SI related to the specific EDG. With the 2A-A EDG out of service, the associated common emergency circuit would not be required to perform any function. The starts were not initiated in response to actual plant conditions or parameters satisfying the requirements for initiation of the system. This event was originally reported under EN 56970 on February 16, 2024, at 0205 EST in accordance with 10 CFR 50.72(b)(3) (iv)(A) as an event that results in a valid actuation of the emergency diesel generator system. This EN was retracted on February 21, 2024, at 1549 EST. This event is being reported in accordance with 10 CFR 50.73(a)(1) and 10 CFR 50.73(a)(2)(iv)(A) as an event that results in an invalid actuation of the emergency diesel generator system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| Where | |
|---|---|
Watts Bar  Tennessee (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1429.23 h59.551 days <br />8.507 weeks <br />1.958 months <br />) | |
| Opened: | Tony Pate 14:38 Apr 15, 2024 |
| NRC Officer: | Sam Colvard |
| Last Updated: | Apr 15, 2024 |
| 57077 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 573362024-08-02T01:27:0002 August 2024 01:27:00
[Table view]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 2024-08-02T01:27:00 | |