ENS 56278
ENS Event | |
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05:51 Dec 17, 2022 | |
Title | Manual Reactor Scram |
Event Description | The following information was provided by the licensee via email:
On December 16, 2022 at 2351 CST, with the Unit in Mode 1 at 13 percent power, a manual scram was inserted due to lowering Reactor Pressure Vessel (RPV) pressure, which occurred following an unexpected opening of Main Turbine Bypass Valve 1. All control rods fully inserted. Following actuation of the manual scram, RPV pressure lowered, resulting in an automatic Primary Containment lsolation (PCIS) Group 1 isolation (expected response). The main steam isolation valves and steam line drain valves all closed. The Group 1 [isolation] has been reset allowing RPV pressure control with steam line drains to the main condenser. All systems responded as designed. The plant is stable in Mode 3. Investigation of the bypass valve opening is ongoing. This event is reportable under 10 CFR 50.72(b)(2)(iv)(B) RPS Actuation and 50.72(b)(3)(iv)(A) Specified System Actuation. There was no impact on health and safety of the public or plant personnel. The NRC Senior Resident Inspector has been notified. |
Where | |
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Cooper Nebraska (NRC Region 4) | |
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:+-1.8 h-0.075 days <br />-0.0107 weeks <br />-0.00247 months <br />) | |
Opened: | Aric Harris 04:03 Dec 17, 2022 |
NRC Officer: | Lloyd Desotell |
Last Updated: | Dec 17, 2022 |
56278 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | Yes, Manual Scram |
Before | Power Operation (13 %) |
After | Hot Standby (0 %) |
Cooper with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 562782022-12-17T05:51:00017 December 2022 05:51:00
[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 Scram ENS 562202022-11-13T04:19:00013 November 2022 04:19:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram ENS 561742022-10-22T17:58:00022 October 2022 17:58:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge ECCS Injection While Shutdown ENS 549762020-11-01T10:34:0001 November 2020 10:34:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to an Un-Isolable Leak on the Turbine High Pressure Fluid System ENS 522612016-09-25T06:03:00025 September 2016 06:03:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Actuation of Group 1 Isolation Signal ENS 454892009-11-11T23:43:00011 November 2009 23:43:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram After a Turbine Hydraulic Fluid Leak ENS 454822009-11-07T01:30:0007 November 2009 01:30:00 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 an Unisolable Leak on the Turbine High Pressure Fluid System ENS 444022008-08-09T07:04:0009 August 2008 07:04:00 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 Failure of Reheat Stop Valve to Open During Turbine Valve Testing ENS 433752007-05-19T07:12:00019 May 2007 07:12:00 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 Control Rod Hcu Valve Bonnet Leak Into Reactor Building ENS 425942006-05-22T12:01:00022 May 2006 12:01:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram as a Mitigating Action Due to Lowering Service Air Pressure ENS 423752006-02-26T08:50:00026 February 2006 08:50:00 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 Msr High Level ENS 420102005-09-23T05:40:00023 September 2005 05:40:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Degrading Main Condenser Vacuum ENS 416012005-04-15T09:36:00015 April 2005 09:36:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Reactor Scram and Specified System Actuations ENS 403622003-11-29T04:02:00029 November 2003 04:02:00 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)(iv)(A), System Actuation - ECCS Discharge Automatic Scram Due to Low Reactor Water Level 2022-12-17T05:51:00 | |