ENS 46311
ENS Event | |
---|---|
04:08 Oct 6, 2010 | |
Title | Valid Actuation of Auxiliary Feedwater System in Response to Valid Steam Generator Low-Low Level Signals |
Event Description | At 0008 on Wednesday, October 6, 2010, Cook Nuclear Plant (CNP) Unit 2 had a Valid Automatic Actuation of the Unit 2 Turbine Driven Auxiliary Feedwater Pump. Cook Nuclear Plant Unit 2 Reactor had been manually tripped at 0001 from 14% power per normal operating procedures in preparation for the Unit 2 refueling outage.
Following the reactor trip, water level in steam generators 23 and 24 lowered to 21% causing an automatic start of the Unit 2 Turbine Driven Auxiliary Feedwater Pump. Manual operator actions were in progress to restore steam generator water levels at the time of the actuation. The Turbine Driven Auxiliary Feedwater Pump operated normally to provide auxiliary feedwater flow to all four Unit 2 steam generators, and steam generator levels were restored to normal post trip values. Prior to the trip of Unit 2 reactor, the Unit 2 East and West Motor Driven Auxiliary Feedwater Pumps were manually started per procedure, as part of the pre-planned reactor trip, to control steam generator water levels. The cause of the low steam generator levels is still under investigation. The licensee has notified the NRC Resident Inspector. |
Where | |
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Cook Michigan (NRC Region 3) | |
Reporting | |
10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
LER: | 05000316/LER-2010-001 |
Time - Person (Reporting Time:+3.08 h0.128 days <br />0.0183 weeks <br />0.00422 months <br />) | |
Opened: | Braddock D. Lewis 07:13 Oct 6, 2010 |
NRC Officer: | Pete Snyder |
Last Updated: | Oct 6, 2010 |
46311 - NRC Website
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Unit 2 | |
---|---|
Reactor critical | Not Critical |
Scram | No |
Before | Hot Standby (0 %) |
After | Hot Standby (0 %) |
WEEKMONTHYEARENS 571952024-06-27T12:04:00027 June 2024 12:04:00
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50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Manual Reactor Trip Due to a Secondary Plant Transient ENS 505872014-11-01T06:48:0001 November 2014 06:48:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Dual Unit Manual Reactor Trips Due to Lowering Condenser Vacuum and Degraded Forebay ENS 492202013-07-28T14:18:00028 July 2013 14:18:00 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 Secondary Plant Transient ENS 489642013-04-24T18:11:00024 April 2013 18:11:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Actuation of an Emergency Diesel Generator Due to a Loss of Train a Reserve Feed to the Site ENS 478812012-05-01T03:28:0001 May 2012 03:28:00 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 Main Turbine Trip ENS 474772011-11-25T10:23:00025 November 2011 10:23:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Aux Feedwater Pump Start After Main Feedwater Pump Trip ENS 472472011-09-07T12:54:0007 September 2011 12:54:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Following Main Turbine Trip from 100% Power ENS 464772010-12-14T02:19:00014 December 2010 02:19:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Actuation of Auxiliary Feedwater System in Response to Loss of One Main Feedwater Pump ENS 463112010-10-06T04:08:0006 October 2010 04:08:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Actuation of Auxiliary Feedwater System in Response to Valid Steam Generator Low-Low Level Signals ENS 458932010-05-02T12:58:0002 May 2010 12:58:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Actuation of Auxiliary Feedwater System in Response to Loss of One Main Feedwater Pump ENS 452282009-07-26T19:06:00026 July 2009 19:06:00 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 Reactor Coolant Pump Seal Malfunction ENS 445072008-09-21T00:18:00021 September 2008 00:18:00 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 Unit 1 Manual Reactor Trip from 100% Power Due to a Fire in the Main Turbine ENS 439562008-02-02T10:30:0002 February 2008 10:30:00 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 Turbine Vibrations ENS 436052007-08-28T17:54:00028 August 2007 17:54:00 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 Digital Feedwater System Failure ENS 425312006-04-27T06:07:00027 April 2006 06:07:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Low Pressure Steam Line Pressure Safety Injection Signal Inadvertently Initiated ENS 421252005-11-08T08:58:0008 November 2005 08:58:00 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 Reactor Coolant Pump Bus Undervoltage ENS 416392005-04-26T04:02:00026 April 2005 04:02:00 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 Afw Actuation ENS 406602004-04-09T02:16:0009 April 2004 02:16:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to a Feedwater Flow Transient ENS 406222004-03-29T19:04:00029 March 2004 19:04:00 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 Reactor Trip Bypass Breaker Manipulation Test ENS 404192003-12-30T18:30:00030 December 2003 18:30:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Tripped from 100% Power Due to Low Steam Generator 2024-06-27T12:04:00 | |