ENS 45833
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ENS Event | |
|---|---|
12:21 Apr 12, 2010 | |
| Title | Actuation of Blackout Sequencers Due to Loss of One Offsite Power Source |
| Event Description | At 0721 [CDT] on 4/12/10 the Comanche Peak Nuclear Power Plant experienced a loss of 138 KV transformer XST1 due to a failed transmission line insulator. Unit 1 is currently defueled per 1RF14 refueling outage schedule. Unit 2 was subjected to actuation of both blackout sequencers causing an automatic start of both motor driven Aux Feedwater (AFW) pumps as well as the turbine driven AFW pump.
No emergency diesel generator started as per design. Train B and the turbine driven AFW pumps have been returned to automatic. Train A AFW pump has been removed from service due to damaged pump packing. Unit 2 is currently operating in Technical Specification (TS) 3.8.1, Condition A, for one required source of offsite power inoperable and in TS 3.7.5, Condition B, for one train of AFW inoperable. With the exception of Train A AFW on Unit 2, all other safety systems functioned per design. The licensee has notified the NRC Resident Inspector. The loss of power to 138 KV transformer XST1 resulted in loss of power to both safeguards busses on Unit 2. The busses performed a load-shed and slow transfer to power supplied from 138 KV transformer XST2 as designed and were re-energized and loads sequenced back onto the busses. The emergency diesel generators are not required to start unless the busses are not re-energized by the alternate offsite transformer. All electrical power related actuations functioned as designed. During this event, the A train AFW pump on Unit 2 started as expected but had to be removed from service due to a pump packing leak. There was no impact on Unit 1 because of its defueled condition. The faulted 138 KV [line] insulator has been repaired, and the Unit 2 safeguard busses have been transferred back to their normal power supplies. The 2-01 motor driven AFW pump has been successfully surveillance tested and is available. Unit 2 remains in TS 3.7.5 condition B pending the close out of an engineering evaluation. No further update notifications are planned. The licensee has informed the NRC Resident Inspector. Notified R4DO (Spitzberg). |
| Where | |
|---|---|
Comanche Peak  Texas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-2.35 h-0.0979 days <br />-0.014 weeks <br />-0.00322 months <br />) | |
| Opened: | Pat Minahan 10:00 Apr 12, 2010 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Apr 12, 2010 |
| 45833 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 570332024-03-17T20:15:00017 March 2024 20:15:00
[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 Due to Main Feedwater Pump Trip ENS 570242024-03-12T13:16:00012 March 2024 13:16:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 565802023-06-16T23:32:00016 June 2023 23:32:00 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 LO-LO Steam Generator Level ENS 560912022-09-06T04:45:0006 September 2022 04:45:00 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 540642019-05-15T02:51:00015 May 2019 02:51:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Voltage Transient Due to Loss of Offsite Switchyard ENS 539062019-03-02T09:17:0002 March 2019 09:17:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip Due to Feedwater Isolation Valve Closure ENS 537672018-12-03T06:00:0003 December 2018 06:00:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Actuation of Blackout Sequencers Due to Loss of One Offsite Power Source ENS 535502018-08-13T05:00:00013 August 2018 05:00:00 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 Generator Lockout ENS 530912017-11-26T02:25:00026 November 2017 02:25:00 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 Main Feed Water ENS 529452017-09-02T02:40:0002 September 2017 02:40:00 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 Two Dropped Rods ENS 528982017-08-11T16:24:00011 August 2017 16:24:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Comanche Peak Automatic Turbine Trip from 10 Percent Power ENS 514442015-10-03T15:00:0003 October 2015 15:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip During Shutdown for a Refueling Outage ENS 497432014-01-18T14:40:00018 January 2014 14:40:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip Due to Turbine Trip ENS 496062013-12-04T19:50:0004 December 2013 19:50:00 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event - Loss of Startup Power Due to a Cut Cable ENS 494972013-11-02T02:47:0002 November 2013 02:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip During Solid State Protection System Testing ENS 485142012-11-17T16:23:00017 November 2012 16:23:00 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 Low Steam Generator Water Level ENS 484752012-11-02T06:42:0002 November 2012 06:42:00 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 High Reactor Coolant Pump Motor Bearing Temperature ENS 468632011-05-19T19:07:00019 May 2011 19:07:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip After a Main Condenser Tube Leak ENS 467482011-04-13T03:15:00013 April 2011 03:15:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Esf Actuation Following Loss of a Safeguard Bus During Edg Testing ENS 458332010-04-12T12:21:00012 April 2010 12:21:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Actuation of Blackout Sequencers Due to Loss of One Offsite Power Source ENS 456172010-01-09T16:28:0009 January 2010 16:28:00 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 on Sudden Pressure in Output Transformer ENS 440672008-03-16T16:37:00016 March 2008 16:37:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip Due to Broken Sensing Line ENS 429452006-10-29T21:20:00029 October 2006 21:20:00 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 Lowering Steam Generator Level ENS 429372006-10-27T08:08:00027 October 2006 08:08:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Loss of Both Main Feed Pumps ENS 414322005-02-23T07:53:00023 February 2005 07:53:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Auxiliary Feedwater Action Following Momentary Power Interruption ENS 411342004-10-19T10:28:00019 October 2004 10:28:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of Normal Power Supply to "2E" Switchgear Resulted in Afw Autostart ENS 404062003-12-22T14:27:00022 December 2003 14:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip Due to Main Turbine Trip 2024-03-17T20:15:00 | |
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