ENS 43185
ENS Event | |
|---|---|
23:56 Feb 24, 2007 | |
| Title | Loss of Normal Electrical Lineup Due to Grid Instability from Adverse Weather Conditions |
| Event Description | Immediate notifications are being made for the following events:
1) Valid RPS non-critical actuation: 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> notification per 50.72(b)(3)(iv)(B) 2) Group 1, 2, 3, 4 and 5 isolations: 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> notification per 50.72(b)(3)(iv)(B) 3) Loss of decay heat removal (RHR Shutdown Cooling) isolated: 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> notification per 50.72(b)(3)(v)(A) 4) Auto start of 'A' Standby Diesel Generator and subsequent pick up of essential buses by both 'A' and 'B' Standby Diesel Generators: 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> notification per 50.72(b)(3)(iv)(A). Just prior to the event the plant was in Mode 5 with core alterations in progress and the 'B' Standby Diesel Generator being run manually for post maintenance testing. At 1756 hours0.0203 days <br />0.488 hours <br />0.0029 weeks <br />6.68158e-4 months <br /> on 2/24/2007, core alterations were halted due to indications that the grid was becoming unstable. Freezing rain had been in progress all day. At 1757 hours0.0203 days <br />0.488 hours <br />0.00291 weeks <br />6.685385e-4 months <br /> an electrical transient occurred as some of the offsite lines coming into the switchyard were lost. The 'B' Reactor Protection System (RPS) bus was lost. A full RPS trip occurred from loss of the 'B' RPS bus and too few inputs to the 'A' RPS trip logic. The loss of 'B' RPS power resulted in Groups 1, 2, 3, 4 and 5 isolations. The Group 4 isolation caused a loss of decay heat removal capability (RHR Shutdown Cooling isolated). The 'A' Standby Diesel Generator auto started, but the 1A3 essential bus remained powered from offsite sources. The 'B' SBDG was already running. The 1A4 bus also remained powered from offsite sources. At 1820 hours0.0211 days <br />0.506 hours <br />0.00301 weeks <br />6.9251e-4 months <br />, a degraded voltage trip signal was received resulting in both emergency diesel generators picking up their respective buses. At present, the essential buses 1A3 and 1A4 are being carried by the emergency diesel generators. Only one of the six lines supplying offsite power to the site is available. Both non-essential buses are being powered from the one offsite line. The emergency buses will remain on the emergency diesel generators until additional offsite lines can be restored. RHR Shutdown Cooling was restored at 1826 hours0.0211 days <br />0.507 hours <br />0.00302 weeks <br />6.94793e-4 months <br />. The licensee notified the NRC Resident Inspector, State and local officials. |
| Where | |
|---|---|
Duane Arnold  Iowa (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-0.88 h-0.0367 days <br />-0.00524 weeks <br />-0.00121 months <br />) | |
| Opened: | David Mankin 23:03 Feb 24, 2007 |
| NRC Officer: | John Knoke |
| Last Updated: | Feb 24, 2007 |
| 43185 - NRC Website
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Duane Arnold with 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 540122019-04-20T10:07:00020 April 2019 10:07:00
[Table view]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 Both Reactor Feed Pumps Trip Causing Manual Reactor Scram and Eccs Injection ENS 536762018-10-19T05:00:00019 October 2018 05:00:00 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 Reactor Trip Due to Feedwater Regulating Valve Failing Closed ENS 514842015-10-20T23:00:00020 October 2015 23:00:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Diesel Generators Started After Transmission Line Lightning Strikes ENS 502462014-07-01T00:13:0001 July 2014 00:13:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Auto-Start of Standby Diesel Generators Due to a Grid Disturbance ENS 475112011-12-02T19:11:0002 December 2011 19:11:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Low Pressure Coolant Injection Inoperable ENS 474482011-11-16T22:22:00016 November 2011 22:22:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Rhr Capability Affected Due to Both Trains of River Water Supply Hvac Systems Inoperable ENS 471432011-08-11T16:38:00011 August 2011 16:38:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unplanned Primary Containment Isolations ENS 471422011-08-11T08:27:00011 August 2011 08:27:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Initiation of Technical Specification Required Shutdown ENS 464102010-11-10T11:18:00010 November 2010 11:18:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Rhr Pump Tripped While Operating in Shutdown Cooling Mode ENS 456032010-01-02T05:10:0002 January 2010 05:10:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Diesel Generator Auto Start Due to Failed Line Arrestor in Switchyard ENS 454212009-10-08T19:20:0008 October 2009 19:20:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram During Testing ENS 451542009-06-23T22:04:00023 June 2009 22:04:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Auto Start of Emergency Diesel Generators Due to Offsite Voltage Transient ENS 449652009-04-03T05:28:0003 April 2009 05:28:00 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 Increasing Reactor Water Level During Calibration ENS 448212009-02-02T00:00:0002 February 2009 00:00:00 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 Loss of Condenser Cooling ENS 438172007-12-01T20:35:0001 December 2007 20:35:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Edg Starts on 161 Kv Line Transient ENS 432712007-04-02T16:25:0002 April 2007 16:25:00 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 Lowering Reactor Vessel Water Level ENS 432472007-03-19T00:40:00019 March 2007 00:40:00 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 Coolant Chemistry Concerns ENS 432102007-03-03T05:32:0003 March 2007 05:32:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Signal Due to High Discharge Volume Level ENS 431852007-02-24T23:56:00024 February 2007 23:56:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of Normal Electrical Lineup Due to Grid Instability from Adverse Weather Conditions ENS 429662006-11-06T07:10:0006 November 2006 07:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram During Turbine Testing ENS 426802006-07-01T04:37:0001 July 2006 04:37:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Common Cause Degradation to Rhr Service Water Pump Motor Cooling Coils ENS 403532003-11-25T21:22:00025 November 2003 21:22:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Scram Due to Degrading Condenser Vacuum During Power Ascension ENS 403012003-11-07T07:34:0007 November 2003 07:34:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Scram at Duane Arnold Due to Hi Coolant Conductivity 2019-04-20T10:07:00 | |