ENS 54176
ENS Event | |
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12:26 Jul 21, 2019 | |
Title | Manual Reactor Trip Due Non-Essential Service Water System Degraded Condition |
Event Description | On July 19, 2019, DC Cook Unit 2 started experiencing degraded performance on the Unit 2 Non-Essential Service Water System (NESW) which affected one (1) NESW pump. On July 21, 2019, a second NESW pump on Unit 2 experienced degradation. On July 21, 2019, DC Cook Unit 2 elected to do a rapid downpower over approximately 40 minutes and perform a Manual Reactor Trip from 17 percent [rated thermal power] to repair the condition before any threshold was exceeded. The manual reactor trip was completed at 0826 EDT on July 21, 2019.
This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation as a four (4) hour report, and under 10 CFR 50.72(b)(3)(iv)(A), Reactor Protection System (RPS), as an eight (8) hour report. The DC Cook NRC Resident Inspector has been notified. Unit 2 is being supplied by offsite power. All control rods fully inserted. Aux Feedwater pumps were started as required and are operating properly. Decay heat is being removed via the Steam Generator Power Operated Relief Valves following breaking Main Condenser Vacuum for expedited cooldown of the Main Turbine. Preliminary evaluation indicates all plant systems functioned normally following the reactor trip. DC Cook Unit 2 remains stable in Mode 3. No radioactive release is in progress as a result of this event. Unit 1 was not affected. |
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 | |
Time - Person (Reporting Time:+-0.3 h-0.0125 days <br />-0.00179 weeks <br />-4.1094e-4 months <br />) | |
Opened: | Perry Graham 12:08 Jul 21, 2019 |
NRC Officer: | Richard Smith |
Last Updated: | Jul 21, 2019 |
54176 - NRC Website
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Unit 2 | |
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Reactor critical | Critical |
Scram | Yes, Manual Scram |
Before | Power Operation (17 %) |
After | Hot Standby (0 %) |
Cook with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | ||
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 553222021-06-23T03:31:00023 June 2021 03:31:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Rx Trip Due to Steam Leak in Moisture Separator Re-Heater Crossover Pipe ENS 549442020-10-12T04:26:00012 October 2020 04:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Automatic Reactor Trip ENS 541762019-07-21T12:26:00021 July 2019 12:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due Non-Essential Service Water System Degraded Condition ENS 533872018-05-07T07:36:0007 May 2018 07:36:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Rx Trip Due to High-High Level in Moisture Separator Drain Tank ENS 533342018-04-13T19:55:00013 April 2018 19:55:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Emergency Diesel Generator Start During Testing ENS 520652016-07-06T04:38:0006 July 2016 04:38:00 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 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] | |