ENS 40660
ENS Event | |
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02:16 Apr 9, 2004 | |
Title | |
Event Description | On April 8, 2004, at about 2215, Cook Unit 2 experienced a feedwater flow transient resulting in oscillating flows to Nr. 22, 23, & 24 steam generators. At 2216, the high level turbine trip setpoint was reached in Nr. 24 steam generator resulting in [a] main turbine trip signal. The main turbine trip signal caused a turbine trip resulting in an RPS [Reactor Protection System] actuation (reactor trip). At the time of the RPS actuation, Cook Unit 2 was at about 50 percent power and lowering power to facilitate turbine control maintenance. The cause of [the] feedwater transient is unknown and under investigation at this time.
Following the RPS actuation, the Auxiliary Feedwater System automatically started on low-low Steam Generator levels. This constituted a valid unplanned actuation of the Engineered Safeguards Feature (ESF). Operators stabilized the Plant using Condenser Steam Dumps and Auxiliary Feedwater. Unit 2 is currently in Mode 3 with Reactor Coolant System conditions stable at normal operating temperature and pressure. No other ESF systems actuated. During the response to the RPS actuation by the operating crew, it was noted that the Main generator output breaker remained closed requiring a manual trip signal to open the output breakers. Another condition identified was a leak from a crack in the side of the 'C' South condenser near the condensate booster pumps' recirculation line inlet. The operating crew removed the condensate booster pumps from service to stop condenser hotwell outleakage; the main condenser remains in service. The causes for the above items are unknown and [are] under investigation at this time. All control rods fully inserted into the core in response to the automatic reactor trip and heat sink is currently been maintained using Auxiliary Feedwater Pumps and the Main Steam Dumps. Except as noted, all other systems functioned as required. The licensee notified the NRC Resident Inspector. |
Where | |
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Cook ![]() Michigan (NRC Region 3) | |
Reporting | |
10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
LER: | 05000316/LER-2004-002 |
Time - Person (Reporting Time:+-0.48 h-0.02 days <br />-0.00286 weeks <br />-6.57504e-4 months <br />) | |
Opened: | Dean Bruck 01:47 Apr 9, 2004 |
NRC Officer: | Arlon Costa |
Last Updated: | Apr 9, 2004 |
40660 - NRC Website
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Unit 2 | |
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Reactor critical | Critical |
Scram | A/R |
Before | Power Operation (50 %) |
After | Hot Standby (0 %) |
Cook ![]() | ||
WEEKMONTHYEARENS 571952024-06-27T12:04:00027 June 2024 12:04:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Start of Turbine Driven Auxiliary Feedwater Pump ENS 571282024-05-15T08:27:00015 May 2024 08:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 2 Manual Reactor Trip ENS 562162022-11-10T12:44:00010 November 2022 12:44:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip and Auxiliary Feedwater System Actuation ENS 560762022-08-28T17:48:00028 August 2022 17:48:00 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 Reactor Coolant Pump Trip ENS 559102022-05-24T08:14:00024 May 2022 08:14:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Following Manual Turbine Trip from High Vibrations on Main Turbine ENS 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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 Manual Reactor Trip and Unusual Event Declaration Due to Steam Leak in Turbine Building ENS 510042015-04-23T06:10:00023 April 2015 06:10:00 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 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 [Table view] | |