ENS 43773
ENS Event | |
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09:06 Nov 7, 2007 | |
Title | Reactor Scram as a Result of Loss of Normal Power 13.8 Kv Bus |
Event Description | With the plant in Mode 1 at [approximately] 75% power, the Auxiliary boiler and water treatment building 480 volt switchgear (NJS-SWG1J) faulted. The fault resulted in the loss of the NPS A bus (13.8 Kv normal supply), causing condensate and feed pumps to trip. Operators in the control room immediately responded and the plant was manually scrammed at 0306. Both the high pressure core spray (HPCS) and the reactor core isolation cooling (RCIC) systems responded automatically and injected into the vessel (valid ECCS signal). Safety systems responded as expected, including level 2 isolations.
The licensee believes a transformer fault may have transferred up the line and caused the loss of normal power supply. RCIC is controlling reactor water level with primary plant pressure approximately 325 psia. Decay heat is being controlled through modulating the SRV's. The licensee has all systems available to place the unit in safe shutdown and cooldown. The licensee has one inoperable EDG and is not in any technical specification action statement at this time. The licensee notified the NRC Resident Inspector.
The high pressure core spray system was returned to its standby lineup at 0318 (all times are CST). Standby service water was being placed in service at 0701 to raise service water header pressure when standby service water pump 'C' started automatically. NPS 13.8kv switchgear 'A' was restored to service at 1245. The reactor core isolation cooling system, which automatically started at the time of the event, was shutdown at 1645. The Division 3 diesel generator, which automatically started at the time of the event, was restored to its standby lineup at 1429. Shutdown cooling was placed in service with residual heat removal pump 'A', at 1626. The plant entered Mode 4 (cold shutdown) at 1942. The electrical fault that initiated the event has been isolated to a 13.8kv/480v transformer in the turbine building. An investigation is ongoing. The licensee notified the NRC Resident Inspector. Notified the R4DO (Spitzberg) and NRR (Lubinski). |
Where | |
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River Bend Louisiana (NRC Region 4) | |
Reporting | |
10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
Time - Person (Reporting Time:+-1.13 h-0.0471 days <br />-0.00673 weeks <br />-0.00155 months <br />) | |
Opened: | Gary Huston 07:58 Nov 7, 2007 |
NRC Officer: | Joe O'Hara |
Last Updated: | Nov 7, 2007 |
43773 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | Yes, Manual Scram |
Before | Power Operation (75 %) |
After | Hot Shutdown (0 %) |
River Bend with 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 | |
WEEKMONTHYEARENS 568872023-12-13T07:02:00013 December 2023 07:02:00
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Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Inadvertent Injection of High Pressure Core Spray ENS 531922018-02-01T16:57:0001 February 2018 16:57:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram ENS 529152017-08-19T01:55:00019 August 2017 01:55:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Scram While at 100 Percent Power ENS 528252017-06-24T01:18:00024 June 2017 01:18:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram on Main Generator Trip ENS 526022017-03-10T13:14:00010 March 2017 13:14:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Closure of the Main Turbine Control Valves ENS 517012016-01-29T21:18:00029 January 2016 21:18:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Specified System Actuation After Loss of One Offsite Power Source ENS 516442016-01-09T08:37:0009 January 2016 08:37:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram on Main Steam Isolation Due to Electrical Fault ENS 515682015-11-27T10:31:00027 November 2015 10:31:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram Following Partial Loss of Offsite Power ENS 511122015-06-02T02:11:0002 June 2015 02:11:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Due to Low Reactor Water Level ENS 508722015-03-08T03:40:0008 March 2015 03:40:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Specified System Actuation Due to Loss of One Reserve Station Service Offsite Power Source ENS 507042014-12-25T14:37:00025 December 2014 14:37:00 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 505462014-10-17T08:03:00017 October 2014 08:03:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram on High Average Power Range Monitor Flux ENS 479602012-05-24T18:48:00024 May 2012 18:48:00 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)(3)(xiii), Loss of Emergency Preparedness Manual Reactor Scram Due to a Loss of Feed as Result of a Loss of Switchgear ENS 479402012-05-21T19:52:00021 May 2012 19:52:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Resulting from a Low Condenser Vacuum-Turbine Trip ENS 475492011-12-23T12:10:00023 December 2011 12:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to a Turbine Trip ENS 453882009-09-29T16:27:00029 September 2009 16:27:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of Water from Upper Refuel Pool ENS 453692009-09-20T22:47:00020 September 2009 22:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Scram Due to Reactor Recirc Pump Trip ENS 440342008-03-05T20:43:0005 March 2008 20:43:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Scram Due to Apparent Malfunction in Turbine Control System ENS 437732007-11-07T09:06:0007 November 2007 09:06:00 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 Reactor Scram as a Result of Loss of Normal Power 13.8 Kv Bus ENS 436682007-09-27T03:44:00027 September 2007 03:44:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram During the Performance of Aprm Surveillance Testing ENS 433452007-05-04T17:56:0004 May 2007 17:56:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Loss of Cooling to Number 2 Main Transformer ENS 429212006-10-19T22:56:00019 October 2006 22:56:00 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 Automatic Scram Following Spontaneous Feedwater Valve Closure ENS 425052006-04-15T21:15:00015 April 2006 21:15:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Scram from 100% Power ENS 413392005-01-15T08:12:00015 January 2005 08:12:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Receiving a Main Generator Alarm ENS 412522004-12-10T19:17:00010 December 2004 19:17:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Scram Due to Loss of Vital Instrument Bus ENS 411652004-11-01T22:44:0001 November 2004 22:44:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Generator Automatic Start ENS 411642004-11-01T03:56:0001 November 2004 03:56:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Plant Had Auto Start of the Division 1 Emergency Diesel Generator ENS 410822004-10-01T12:30:0001 October 2004 12:30:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Reactor Trip Due to Main Generator Load Rejection ENS 409572004-08-15T09:05:00015 August 2004 09:05:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram Following Partial Loss of Offsite Power ENS 401912003-09-23T03:43:00023 September 2003 03:43:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Received During Main Turbine Control Valve Testing 2023-12-13T07:02:00 | |