ENS 57043
ENS Event | |
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01:56 Mar 22, 2024 | |
Title | Automatic Turbine Driven Auxiliary Feedwater Pump Actuation |
Event Description | The following information was provided by the licensee via email:
At 2056 on 3/21/24, Callaway Plant was in Mode 1 at approximately 100 percent power when an automatic start of the turbine driven auxiliary feedwater pump occurred. The event occurred while restoring inverter NN12 from maintenance. NN12 is the normal in-service inverter for the group 2 120-VAC instrument bus (NN02). The actuation occurred while swapping from the swing inverter (NN18) to the normal in-service inverter (NN12). All safety systems responded as expected. At 2334, the turbine driven auxiliary feedwater pump was secured. The plant is being maintained in a stable condition, in mode 1. The NRC Resident Inspector was notified The licensee is investigating the cause of the automatic start.
Event Notification (EN) 57043, made on 03/21/2024 pursuant to 10 CFR 50.72(b)(3)(iv)(A), is being retracted based upon further investigation into the cause of the turbine driven auxiliary feedwater pump (TDAFP) actuation. The TDAFP received an invalid manual initiation signal caused by a voltage transient that was generated on the NK02 125-VDC bus upon closure of downstream breaker NK0211 (while restoring inverter NN12 from maintenance). This actuation signal was due to degradation of a 48-VDC power supply (PS1) within engineered safety features actuation system (ESFAS) logic cabinet SA036C. This degradation likely prevented the power supply from sufficiently filtering the transient that occurred on the 125-VDC bus associated with the NN12 inverter. Notified R4DO (Warnick) |
Where | |
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Callaway ![]() Missouri (NRC Region 4) | |
Reporting | |
10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
Time - Person (Reporting Time:+-0.17 h-0.00708 days <br />-0.00101 weeks <br />-2.32866e-4 months <br />) | |
Opened: | Greg Cizin 01:46 Mar 22, 2024 |
NRC Officer: | Bill Gott |
Last Updated: | Apr 25, 2024 |
57043 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |
WEEKMONTHYEARENS 570432024-03-22T01:56:00022 March 2024 01:56:00
[Table view]10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Turbine Driven Auxiliary Feedwater Pump Actuation ENS 569682024-02-15T08:47:00015 February 2024 08:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Turbine Trip/Reactor Trip ENS 556982022-01-07T18:23:0007 January 2022 18:23:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Turbine Trip / Reactor Trip ENS 540692019-05-17T04:03:00017 May 2019 04:03:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation En Revision Imported Date 6/6/2019 ENS 540052019-04-17T06:37:00017 April 2019 06:37:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Undervoltage to a Safety Related Bus Resulting in Valid System Actuation ENS 518462016-04-03T04:02:0003 April 2016 04:02:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Protection System Actuation While Reactor Shutdown ENS 513082015-08-11T06:39:00011 August 2015 06:39:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip After an Offsite Electrical Fault ENS 512572015-07-23T18:57:00023 July 2015 18:57:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Auxiliary Feedwater Manual Start Due to Loss of Main Feedwater Pump During Plant Cooldown ENS 506502014-12-03T06:22:0003 December 2014 06:22:00 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 Turbine Trip ENS 492192013-07-27T04:49:00027 July 2013 04:49:00 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(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event Declared Due to a Fire in the Turbine Building Lasting Greater than 15 Minutes ENS 457152010-02-20T03:45:00020 February 2010 03:45:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Specified System Actuations Due to Loss of the 'A' Safeguards Transformer ENS 447192008-12-14T23:14:00014 December 2008 23:14:00 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 Electrical Fault on an Operating Condensate Pump ENS 447172008-12-12T16:42:00012 December 2008 16:42:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Inadvertent Valid Reactor Trip and Feedwater Isolation Signals Due to Maintenance ENS 447142008-12-12T05:01:00012 December 2008 05:01:00 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 a Feedwater Transient ENS 446522008-11-12T00:46:00012 November 2008 00:46:00 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 a Feedpump Trip ENS 445612008-10-11T10:08:00011 October 2008 10:08:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Steam Generator Water Level Trip Actuation Initiated Reactor Trip System ENS 432272007-03-09T16:43:0009 March 2007 16:43:00 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 Manual Reactor Trip at Reduced Power Due to Inadequate Feedwater Control ENS 426212006-06-06T18:39:0006 June 2006 18:39:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of "a" Train of Offsite Vital Power Due to Relay Testing ENS 425712006-05-12T05:53:00012 May 2006 05:53:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip on High Steam Generator Level ENS 415462005-03-29T16:57:00029 March 2005 16:57:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Actuation of the Reactor Protection System and Auxiliary Feedwater System While Establishing Initial Conditions for Leak Test in Mode 3. ENS 413472005-01-19T18:51:00019 January 2005 18:51:00 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 Callaway Automatic Reactor Trip on Low Steam Generator Level ENS 405222004-02-15T21:19:00015 February 2004 21:19:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip with Auxiliary Feedwater Actuation ENS 405152004-02-12T04:58:00012 February 2004 04:58:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Eccs Actuation During Rcs Heatup ENS 405002004-02-03T10:39:0003 February 2004 10:39:00 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 Main Genrator Output Breakers Opening. ENS 403172003-11-12T20:21:00012 November 2003 20:21:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Inadvertent Actuation of Essential Service Water System 2024-03-22T01:56:00 | |