ENS 53105
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ENS Event | |
|---|---|
02:00 Dec 6, 2017 | |
| Title | Unplanned Loss of Multiple Radiation Monitors During Maintenance |
| Event Description | At 2000 (CST), Comanche Peak experienced a failure of SCADA B of the PC11 Radiation Monitor System. This failure caused a loss of Unit 1 Main Steam Line 1-01 and 1-03 Radiation Monitors (1-RE-2325 and 1-RE-2327) and Train A and Train B Station Service Water Radiation Monitors (1-RE-4269 and 1-RE-4270). With the Main Steam Line Radiation Monitors nonfunctional, all of the emergency action levels for a steam generator tube rupture in steam generators 1-01 and 1-03 could neither be evaluated nor monitored. With the Station Service Water Radiation Monitors non-functional, all of the emergency action levels for a radioactive release through station service water could neither be evaluated nor monitored. This unplanned condition is reportable as a loss of assessment capability per 10 CFR 50.72(b)(3)(xiii).
Comanche Peak Nuclear Power Plant (CPNPP) has assurance of steam generator integrity, reactor coolant system integrity, and fuel cladding integrity and there is a negligible safety significance to condition from a public health and safety perspective. Additionally, compensatory measures are in place to assure adequate monitoring capability is available to implement the CPNPP emergency plan in the unlikely event of challenges to the steam generator, reactor coolant system, or the fuel cladding. Until these radiation monitors were restored, Operations implemented compensatory measures to monitor the Condenser Off Gas Radiation Monitor for early signs of a steam generator tube leak/rupture and Radiation Technicians were briefed on taking local readings with a Geiger-Mueller tube on the Main Steam Lines. Chemistry Technicians were performing hourly samples of Station Service Water and reporting results to the Control Room. Corrective actions were pursued to restore the non-functional radiation monitors back to service. Those actions are complete and all radiation monitors have been restored to service. The NRC Resident Inspector has been notified. PC11 is a computer common to both Units. The failure happened during radiation monitor maintenance to a single monitor, which unexpectedly affected multiple monitors. |
| Where | |
|---|---|
Comanche Peak  Texas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | |
| Time - Person (Reporting Time:+-0.08 h-0.00333 days <br />-4.761905e-4 weeks <br />-1.09584e-4 months <br />) | |
| Opened: | Christopher Metz 01:55 Dec 6, 2017 |
| NRC Officer: | Bethany Cecere |
| Last Updated: | Dec 6, 2017 |
| 53105 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 556942022-01-07T07:20:0007 January 2022 07:20:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Meteorological Emergency Assessment Capability ENS 553052021-06-13T03:27:00013 June 2021 03:27:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Main Steam Line (Msl) Radiation Monitor Non-Functional ENS 553042021-06-12T22:25:00012 June 2021 22:25:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Main Steam Line (Msl) Radiation Monitor Non-Functional ENS 549292020-09-30T13:15:00030 September 2020 13:15:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Radiation Monitors Required for Event Assessment Out of Service for Planned Maintenance ENS 544332019-12-10T15:20:00010 December 2019 15:20:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Planned Loss of Emergency Response Facilities and Equipment ENS 544302019-12-10T03:26:00010 December 2019 03:26:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Main Steam Line (Msl) Radiation Monitor to Be Non-Functional ENS 543672019-11-03T14:00:0003 November 2019 14:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness En Revision Imported Date 12/11/2019 ENS 543292019-10-14T14:11:00014 October 2019 14:11:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Main Steam Line (Msl) Radiation Monitor Removed from Service for Planned Maintenance ENS 534722018-06-26T05:00:00026 June 2018 05:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Main Steam Line Radiation Monitor Determined to Be Non-Functional ENS 534232018-05-23T13:48:00023 May 2018 13:48:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Emergency Assessment Capability ENS 533802018-05-03T17:20:0003 May 2018 17:20:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Emergency Assessment Capability ENS 532122018-02-15T09:06:00015 February 2018 09:06:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Main Steam Line Radiation Monitor Determined to Be Non Functional ENS 531542018-01-06T17:26:0006 January 2018 17:26:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Main Steam Line Radiation Monitor Determined to Be Non-Functional ENS 531432018-01-02T17:37:0002 January 2018 17:37:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Unplanned Loss of Emergency Response Equipment Due to Loss of Plant Computer ENS 531052017-12-06T02:00:0006 December 2017 02:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Unplanned Loss of Multiple Radiation Monitors During Maintenance ENS 529372017-08-30T07:10:00030 August 2017 07:10:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Unplanned Loss of Emergency Response Equipment ENS 523632016-11-13T16:12:00013 November 2016 16:12:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness One Main Steam Line Radiation Monitor Failed ENS 519552016-05-24T15:22:00024 May 2016 15:22:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Unplanned Loss of Emergency Assessment Capability ENS 518712016-04-19T18:43:00019 April 2016 18:43:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Main Steam Line Radiation Detector Determined to Be Non Functional ENS 517172016-02-09T14:12:0009 February 2016 14:12:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Planned Maintenance of the Plant Computer System ENS 516392016-01-07T13:59:0007 January 2016 13:59:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Both Meteorological Towers Due to Power System Failure ENS 509652015-04-07T16:00:0007 April 2015 16:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Inoperable Seismic Instrumentation Identified During Historical Review ENS 509552015-04-05T13:52:0005 April 2015 13:52:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Both Primary and Backup Meteorological Towers Due to Partial Loss of 25Kv Power Distribution ENS 507732015-01-28T16:18:00028 January 2015 16:18:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Emergency Operations Facility Unavailable Due to Planned Ventilation Maintenance ENS 507152015-01-03T11:38:0003 January 2015 11:38:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Meteorological Emergency Assessment Capability ENS 507132015-01-02T09:14:0002 January 2015 09:14:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Meteorological Emergency Assessment Capability ENS 503502014-08-07T14:25:0007 August 2014 14:25:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Emergency Operations Facility Air Conditioning Operating at Reduced Capacity ENS 489532013-04-22T14:00:00022 April 2013 14:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Emergency Operations Facility Not Available ENS 483522012-09-27T17:54:00027 September 2012 17:54:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Partial Loss of Emergency Assessment During Planned Modifications ENS 483182012-09-18T15:55:00018 September 2012 15:55:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Outage of Plant Radiation Monitoring System Remote Readout Due to Planned Modification ENS 482472012-08-29T13:57:00029 August 2012 13:57:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Partial Loss of Plant Radiation Monitoring System Remote Readout ENS 447642009-01-13T08:19:00013 January 2009 08:19:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Communications Capability Due to a Fiber Optic Cable Cut ENS 442822008-06-10T15:11:00010 June 2008 15:11:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of the Safety Parameter Display System ENS 441912008-05-07T16:00:0007 May 2008 16:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Multiplexer Power Supply ENS 422042005-12-13T19:45:00013 December 2005 19:45:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Offsite Notification ENS 408842004-07-20T20:39:00020 July 2004 20:39:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Emergency Assessment Capability Exceeding 8 Hours 2022-01-07T07:20:00 [Table view] | |
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