ENS 47813
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ENS Event | |
|---|---|
19:44 Apr 6, 2012 | |
| Title | Valid Load Shed Signal Occurred Due to Loss of the 1B Startup Transformer |
| Event Description | At 1444 [CDT] on April 6, 2012, during a planned refueling outage on Unit 1, maintenance activities in the high voltage switchyard caused feeder breaker 820 to inadvertently trip. With the second feeder breaker, 924, already out of service, power was lost to the 1B startup transformer. An undervoltage condition was then experienced on the 1G 4160 V emergency bus. As a result, the B1G Sequencer initiated a valid load shed of the 1G 4160 V emergency bus. Due to outage conditions, the B-Train, 1B Emergency Diesel Generator (EDG) was tagged out and did not automatically start but did receive a valid start signal. None of the ESF loads supplied by the 1G bus started automatically since the 1B EDG was out of service. With a B-Train equipment outage in progress, the 1A RHR pump (A-Train) remained in service for shutdown cooling throughout the event. Although the bus safety function was not needed for plant conditions a valid load shed signal occurred and therefore this event is considered reportable.
The 1G 4160 V emergency bus was restored to service at 1542 on April 6, 2012. Investigation revealed a technical inaccuracy in the instructions used during the maintenance activity in the high voltage switchyard that caused feeder breaker 820 to trip. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Farley  Alabama (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+2.57 h0.107 days <br />0.0153 weeks <br />0.00352 months <br />) | |
| Opened: | Darrin Gard 22:18 Apr 6, 2012 |
| NRC Officer: | Vince Klco |
| Last Updated: | Apr 6, 2012 |
| 47813 - NRC Website | |
WEEKMONTHYEARENS 569712024-02-16T11:34:00016 February 2024 11:34:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip and Automatic Actuation of Auxiliary Feedwater System ENS 568522023-11-14T16:41:00014 November 2023 16:41:00 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 563292023-02-01T15:56:0001 February 2023 15:56:00 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 and Automatic Actuation of Auxiliary Feedwater System ENS 560282022-08-03T17:58:0003 August 2022 17:58:00 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 Loss of Power to START-UP Transformer ENS 542872019-09-21T13:00:00021 September 2019 13:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Trip Due to Reactor Coolant Pump Vibration Alarm ENS 540402019-05-01T21:43:0001 May 2019 21:43:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation En Revision Imported Date 5/9/2019 ENS 523952016-11-27T06:26:00027 November 2016 06:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip with Automatic Auxiliary Feedwater System Actuation Due to Voltage Oscillations ENS 523562016-11-08T06:00:0008 November 2016 06:00:00 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 Generator Reduced Feedflow ENS 522742016-10-01T10:12:0001 October 2016 10:12:00 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)(iv)(A), System Actuation - ECCS Discharge Automatic Reactor Trip Due to Inadvertent Closure of Main Steam Isolation Valve ENS 519182016-05-11T11:53:00011 May 2016 11:53:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Farley Unit 2 Trip on Hi Hi Steam Generator Level ENS 510432015-05-05T09:22:0005 May 2015 09:22:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Auxiliary Feedwater Pump Auto Start Signal Initiated During Startup ENS 506182014-11-15T09:53:00015 November 2014 09:53:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Actuation of the Reactor Protection System for Abnormal Rod Position Indication ENS 505332014-10-14T08:41:00014 October 2014 08:41:00 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 Loss of a Start-Up Transformer ENS 491062013-06-12T02:05:00012 June 2013 02:05:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 1 Automatic Reactor Trip Due to the Loss of a Start-Up Transformer ENS 478132012-04-06T19:44:0006 April 2012 19:44:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Load Shed Signal Occurred Due to Loss of the 1B Startup Transformer ENS 478092012-04-05T17:20:0005 April 2012 17:20:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unplanned Systems Actuations While Performing a Surveillance Test ENS 466612011-03-07T07:40:0007 March 2011 07:40:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Inadvertant Auto-Start Signal to the 1B Diesel Generator During Testing ENS 459462010-05-22T21:34:00022 May 2010 21:34:00 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 Loss of Steam Generator Water Level Control ENS 458892010-05-01T02:00:0001 May 2010 02:00:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Inadvertent System Actuation Occurred During a Surveillance Test ENS 448552009-02-16T22:55:00016 February 2009 22:55:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Inadvertent Relay Actuation Results in Auto Start of 1C Emergency Diesel Generator ENS 436872007-10-03T19:10:0003 October 2007 19:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip on Loss of Forced Flow to Rcs Loop "a ENS 411752004-11-05T15:11:0005 November 2004 15:11:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Inadvertent Loss of "B" Train Site Power During Testing ENS 405582004-03-01T11:22:0001 March 2004 11:22:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 1 Experienced a Reactor Trip on Turbine Trip Due to a Feedwater System Problem ENS 403092003-11-10T16:36:00010 November 2003 16:36:00 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 False Rcp Breaker Open Signal 2024-02-16T11:34:00 | |
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