ENS 53110
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ENS Event | |
|---|---|
19:48 Dec 9, 2017 | |
| Title | Manual Reactor Scram Due to Loss of Division 1 Ac Power to Numerous Components |
| Event Description | At approximately 1347 [CST] on 12/09/17, the Main Control Room received annunciators that indicated a trip of the 4160 V 1A1 breaker 1AP07EJ, 480V XFMR 1A and A1 breaker. Numerous Division 1 components lost power (powered from unit subs 1A and A1). The Division 1 containment Instrument Air isolation valves had failed closed by design due to the loss of power. Due to the loss of containment instrument air, several control rods began to drift into the core as expected and, by procedure, the reactor mode switch was placed in the shutdown position at 1353 [CST]. All control rods fully inserted.
Also due to the loss of power, the Fuel Building ventilation dampers failed closed by design. With the normal ventilation system secured, secondary containment differential pressure rose to slightly greater than 0 inches water gauge which exceeded the Technical Specification requirement of greater than 0.25 inches vacuum water gauge at 1348 [CST]. The Control Room entered EOP-8, Secondary Containment Control. Secondary Containment differential pressure was restored within Technical Specification requirements at 1351 [CST] by starting the Division 2 Standby Gas Treatment system. This event is being reported as a manual actuation of the Reactor Protection System (RPS) and as a Condition that Could Have Prevented Fulfillment of a Safety Function. The cause is currently under investigation. The NRC Resident has been notified. The licensee informed the NRC Resident Inspector.
During a review of plant logs it was identified that the primary to secondary containment differential pressure was identified to be outside of Technical Specification 3.6.1.4 limits of 0 plus or minus 0.25 psid at 2009 on 12/9/17 due to the primary containment ventilation system dampers closing as a result of the loss of power. This parameter is an initial safety analysis assumption to ensure that primary containment pressures remain within the design values during a Loss of Coolant Accident (LOCA). As a result, this condition is reportable as an unanalyzed condition that significantly degrades plant safety. The NRC Senior Resident Inspector has been notified. Notified the R3DO (Stone).
During the post transient review of the trip of the 4160 V 1A1 breaker 1AP07EJ, 480V XFMR 1A and A1, it was identified that the unplanned INOPERABILITY of the Low Pressure Core Spray (LPCS) system due to the loss of power to the injection valve constitutes an event or condition that could have prevented fulfillment of a safety function and is reportable under 10CFR50.72(b)(3)(v)(D) for Accident Mitigation. The High Pressure Core Spray (HPCS) remained available to perform the core spray function, if necessary, during a design basis Loss of Coolant Accident (LOCA), however HPCS and LPCS are each considered single train safety systems. The NRC Senior Resident Inspector has been notified. Notified the R3DO (Stone). |
| Where | |
|---|---|
Clinton  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+-1.1 h-0.0458 days <br />-0.00655 weeks <br />-0.00151 months <br />) | |
| Opened: | Dale Shelton 18:42 Dec 9, 2017 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Dec 11, 2017 |
| 53110 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (98 %) |
| After | Hot Shutdown (0 %) |
Clinton with 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)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
WEEKMONTHYEARENS 563282023-02-01T05:43:0001 February 2023 05:43:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Scram Due to Turbine Trip ENS 550022020-11-17T01:18:00017 November 2020 01:18:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Both Trains of Main Control Room Ventilation and Air Conditioning Systems Inoperable ENS 544032019-11-21T18:25:00021 November 2019 18:25:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident ENS 542812019-09-16T13:17:00016 September 2019 13:17:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Accident Mitigation ENS 541972019-08-03T07:26:0003 August 2019 07:26:00 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 En Revision Imported Date 8/7/2019 ENS 538242019-01-13T14:30:00013 January 2019 14:30:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident En Revision Imported Date 3/8/2019 ENS 536982018-10-28T05:00:00028 October 2018 05:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram During a Reactor Shutdown ENS 534632018-06-20T05:00:00020 June 2018 05:00:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High-Pressure Core Spray Inoperable ENS 534092018-05-17T20:03:00017 May 2018 20:03:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Emergency Diesel Generators Inoperable ENS 533032018-03-30T18:05:00030 March 2018 18:05:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Primary Containment Declared Inoperable Due to Both Airlock Doors Open Simultaneously ENS 531102017-12-09T19:48:0009 December 2017 19:48:00 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)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Manual Reactor Scram Due to Loss of Division 1 Ac Power to Numerous Components ENS 530542017-11-05T18:40:0005 November 2017 18:40:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Pressure Due to Voltage Transient ENS 528062017-06-15T14:58:00015 June 2017 14:58:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Core Spray Declared Inoperable ENS 528002017-06-11T03:56:00011 June 2017 03:56:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Loss of Feedwater Heating ENS 527822017-06-02T07:41:0002 June 2017 07:41:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Declared Inoperable ENS 527772017-05-31T01:38:00031 May 2017 01:38:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram ENS 526012017-03-09T09:19:0009 March 2017 09:19:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Relay Failure ENS 525762017-02-25T04:39:00025 February 2017 04:39:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Differentail Pressure Exceeded Technical Specifications ENS 523772016-11-17T23:00:00017 November 2016 23:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Incorrect Method Used for Calculation of Control Room Habitability ENS 520432016-06-24T20:11:00024 June 2016 20:11:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment ENS 518452016-04-02T17:57:0002 April 2016 17:57:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Insulator Failure on Reserve Auxiliary Transformer ENS 518362016-03-30T20:45:00030 March 2016 20:45:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Differential Pressure Outside Required Technical Specification Value ENS 517322016-02-13T08:06:00013 February 2016 08:06:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable ENS 516692016-01-20T19:11:00020 January 2016 19:11:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Primary-Secondary Containment Pressure Differential Exceeded Due to Ccp Exhaust Fan Trip ENS 511792015-06-25T08:01:00025 June 2015 08:01:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Pressure Increase Due to Voltage Transient ENS 507942015-02-07T05:55:0007 February 2015 05:55:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Leakage Detection System Inoperable ENS 504632014-09-17T00:05:00017 September 2014 00:05:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Loss of Division 3 of Shutdown Service Water Requires Hpcs to Be Declared Inoperable ENS 499582014-03-26T00:42:00026 March 2014 00:42:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Loss of Condenser Vacuum ENS 497582014-01-23T01:56:00023 January 2014 01:56:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Differential Pressure ENS 496322013-12-13T23:57:00013 December 2013 23:57:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip During Feed Pump Swap ENS 496172013-12-09T02:27:0009 December 2013 02:27:00 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)(v)(C), Loss of Safety Function - Release of Radioactive Material Manual Scram Due to Loss of Division 1 480 Vac Power Causing Loss of Instrument Air to Containment and Scram Air Header ENS 493732013-09-20T14:17:00020 September 2013 14:17:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Safe Shutdown Analysis Reveals Noncompliance for a Fire Outside Diesel Room ENS 492862013-08-15T14:15:00015 August 2013 14:15:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Diesel Generator Declared Inoperable Due to Damper Failing to Open ENS 489742013-04-26T13:55:00026 April 2013 13:55:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Rapidly Decreasing Level in the Ehc Oil Reservoir ENS 488122013-03-07T13:56:0007 March 2013 13:56:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram on Generator Trip/Turbine Trip ENS 487652013-02-18T09:18:00018 February 2013 09:18:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Core Spray Declared Inoperable ENS 485332012-11-24T02:08:00024 November 2012 02:08:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Inadvertent Loss of Instrument Air ENS 482692012-09-03T03:04:0003 September 2012 03:04:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Transfer of Emergency Reserve Auxiliary Transformer Isolating Fuel Pool Cooling and Cleanup System, and Fuel Building Ventilation System ENS 475102011-12-08T11:00:0008 December 2011 11:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Non Fused Dc Bus Ammeters Could Short and Cause a Fire ENS 474892011-11-29T23:28:00029 November 2011 23:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Unit Experienced an Automatic Reactor Scram During a Planned Shutdown ENS 466032011-02-08T14:00:0008 February 2011 14:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Event Could Initiate High Pressure Core Spray and Overfill the Reactor Pressure Vessel ENS 456762010-02-03T17:00:0003 February 2010 17:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Feedwater Check Valve Leak Rate Exceeded Technical Specification Requirement ENS 454332009-10-15T10:37:00015 October 2009 10:37:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Reactor Recirculation Pump Trip ENS 451812009-07-02T19:15:0002 July 2009 19:15:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Hpcs Inoperable Due to Logic Card Failure ENS 451222009-06-10T14:20:00010 June 2009 14:20:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Unknown Cable with Combustible Coating Found in Division I / Division II Cable Tray ENS 439762008-02-11T04:07:00011 February 2008 04:07:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Increasing Reactor Vessel Level ENS 434162007-06-11T01:03:00011 June 2007 01:03:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Core Spray Declared Inoperable Due to Failed Inverter ENS 429782006-11-09T12:44:0009 November 2006 12:44:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Core Spray System Valve Inadvertently De-Energized ENS 429292006-10-24T06:42:00024 October 2006 06:42:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Core Spray (Hpcs) Declared Inoperable for Approx. 3.4 Hours ENS 428072006-08-27T22:05:00027 August 2006 22:05:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Trip Due to Reactor High Water Level ENS 427822006-08-17T15:44:00017 August 2006 15:44:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Main Turbine Bypass Valves Inoperable ENS 424302006-03-20T10:53:00020 March 2006 10:53:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Main Turbine Trip Caused Reactor Scram ENS 409832004-08-24T14:17:00024 August 2004 14:17:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Core Spray (Hpcs) Declared Inoperable ENS 408682004-07-13T21:10:00013 July 2004 21:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to Possible Adverse Weather ENS 406522004-04-06T19:00:0006 April 2004 19:00:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Air Valve Misalignment Reduces Standby Liquid Control Capability ENS 406042004-03-23T01:31:00023 March 2004 01:31:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Scram from 93% Power Due to Generator Trip ENS 403682003-12-02T22:58:0002 December 2003 22:58:00 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 Low Reactor Water Feed Pump Suction Pressure 2023-02-01T05:43:00 | |
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