ENS 56978
ENS Event | |
|---|---|
07:36 Feb 19, 2024 | |
| Title | Automatic Start of B Emergency Diesel Generator |
| Event Description | The following information was provided by the licensee via phone and email:
On February 19, 2024, at 0236 EST, with VC Summer Unit 1 in Mode 1 at 100 percent power, an actuation of the `B emergency diesel generator (EDG) occurred. The reason for the `B EDG auto-start was the trip of 1 `DB normal incoming breaker. The `B EDG automatically started as designed when the undervoltage signal was received. The `B emergency feedwater pump started due to the undervoltage signal and ran for approximately 1 minute and was secured by operations per procedure. Other plant equipment and systems also responded as expected. This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the `B EDG and a valid actuation of the `B emergency feedwater pump. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The `A Emergency Diesel Generator was tagged out for maintenance earlier in the shift, but maintenance has not started. The plan is to restore the `A emergency diesel generator to an operable status and investigate the cause of the 1 `DB normal incoming breaker trip. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: This event resulted in the plant entering a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> limiting condition for operation (LCO) in accordance with technical specification (TS) 3.8.1.1.C. due to having one operable EDG and a loss of offsite power.
VC Summer is retracting event notification (EN) 56978 regarding the unexpected actuations of the B emergency diesel generator and B emergency feedwater pump on 02/19/2024. Both were previously reported as valid actuations under 10 CFR 50.72(b)(3)(iv)(A). Subsequent evaluation has determined that the actuations were the result of an invalid signal caused by equipment failure on the 1 DB bus undervoltage control circuit. The event, its cause, and corrective actions were reported in VC Summer licensee event report 2024-001-00 (ML24108A143) on 04/17/2024, pursuant to the requirements of 10 CFR 50.73(a)(2)(iv)(A). There was no impact on the health and safety of the public or plant personnel as a result of the actuations. The NRC Senior Resident Inspector has been notified. Notified R2DO (Franke) |
| Where | |
|---|---|
Summer  South Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-1.07 h-0.0446 days <br />-0.00637 weeks <br />-0.00147 months <br />) | |
| Opened: | Jason Pawlak 06:32 Feb 19, 2024 |
| NRC Officer: | Ernest West |
| Last Updated: | Jun 6, 2024 |
| 56978 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 569782024-02-19T07:36:00019 February 2024 07:36:00
[Table view]10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Start of B Emergency Diesel Generator ENS 564532023-04-05T10:51:0005 April 2023 10:51:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip ENS 555802021-11-15T22:28:00015 November 2021 22:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Main Transformer Fault ENS 531762018-01-18T17:02:00018 January 2018 17:02:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Generator Actuation Due to Loss of One of Two Offsite Power Supplies ENS 530602017-11-08T00:57:0008 November 2017 00:57:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip on Turbine Trip ENS 529622017-09-11T20:48:00011 September 2017 20:48:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Generator Actuation on Low Voltage ENS 529322017-08-28T12:37:00028 August 2017 12:37:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip on Turbine Trip ENS 528332017-06-29T12:57:00029 June 2017 12:57:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Trip Due to a Loss of Normal Feedwater Flow to B Steam Generator ENS 502932014-07-22T08:14:00022 July 2014 08:14:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Low Steam Generator Level ENS 488462013-03-24T08:58:00024 March 2013 08:58:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Start of an Emergency Diesel Generator Due to a Lightning Strike ENS 468992011-05-27T16:00:00027 May 2011 16:00:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Safety Injection Initiated Due to a High Differential Pressure Between Main Steam Lines ENS 455772009-12-16T19:15:00016 December 2009 19:15:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Following a Failure of the Steam Dump System ENS 454042009-10-02T10:49:0002 October 2009 10:49:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip on Turbine Trip Possibly Caused by a Faulted Main Generator Breaker ENS 442312008-05-21T21:04:00021 May 2008 21:04:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Generator Shifted to Emergency Start During Post Maintenance Test ENS 439322008-01-24T21:04:00024 January 2008 21:04:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Failure of the "C" Feedwater Flow Control Valve ENS 431412007-02-05T08:07:0005 February 2007 08:07:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Steam Leak During Main Feed Booster Pump Startup ENS 430042006-11-22T09:26:00022 November 2006 09:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Main Turbine Trip Due to High- High Steam Generator "B" Water Level During Feedwater Swap Over. ENS 429982006-11-09T19:44:0009 November 2006 19:44:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Generator Actuation During Testing ENS 417062005-05-18T05:54:00018 May 2005 05:54:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of Balance of Plant Power Due to Transformers Lockout ENS 408112004-06-13T00:29:00013 June 2004 00:29:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Started and Loaded on Bus Undervoltage Signal ENS 406282004-03-30T16:29:00030 March 2004 16:29:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Automatic Reactor Trip Due to Lo-Lo Steam Generator Level ENS 403482003-11-21T14:10:00021 November 2003 14:10:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Control Bank "C" Rods Tripped Due to Incorrect Digital Rod Position Indication (Drpi) 2024-02-19T07:36:00 | |