ENS 52989
ENS Event | |
---|---|
22:00 Sep 22, 2017 | |
Title | Seismic Monitoring Computer Out-Of-Service |
Event Description | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10 CFR 50.73.
This event is being reported pursuant to 10 CFR 50.72(b)(3)(xiii) for a major loss of emergency assessment capability at the Palo Verde Nuclear Generating Station (PVNGS). On September 21, 2017 at 0915 MST, the seismic monitoring (SM) computer was declared non-functional for the performance of a planned surveillance test. On September 21, 2017 at 1201 MST, the SM system computer became non-responsive during the performance of the test. Control room staff attempted to reboot the computer and were unsuccessful. Maintenance and troubleshooting efforts began thereafter to initiate repairs. As a compensatory measure, PVNGS procedures for seismic event evaluation provide alternative methods for event classification of a seismic event with the SM system out of service. The SM system functions to provide indication that the Operational Basis Earthquake (OBE) threshold has been exceeded following a seismic event and is used in the PVNGS Emergency Plan to perform classification of Initiating Condition 'Seismic event greater than OBE levels' and Emergency Action Level HU2.1. On September 22, 2017 at 1500 MST, maintenance personnel performing software repair efforts determined hardware replacement is required. The required component will not be available before 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from the start of the event. Because the SM system is not expected to be restored within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, this condition is being reported as a planned event constituting a major loss of emergency assessment capability with viable compensatory measures in place. The NRC Resident Inspector has been informed of this condition. |
Where | |
---|---|
Palo Verde Arizona (NRC Region 4) | |
Reporting | |
10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | |
Time - Person (Reporting Time:+-1.87 h-0.0779 days <br />-0.0111 weeks <br />-0.00256 months <br />) | |
Opened: | Robert Chu 20:08 Sep 22, 2017 |
NRC Officer: | Steven Vitto |
Last Updated: | Sep 22, 2017 |
52989 - NRC Website
Loading map... {"minzoom":false,"maxzoom":false,"mappingservice":"leaflet","width":"350px","height":"250px","centre":false,"title":"","label":"","icon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"zoom":6,"defzoom":14,"layers":["OpenStreetMap"],"image layers":[],"overlays":[],"resizable":false,"fullscreen":false,"scrollwheelzoom":true,"cluster":false,"clustermaxzoom":20,"clusterzoomonclick":true,"clustermaxradius":80,"clusterspiderfy":true,"geojson":"","clicktarget":"","imageLayers":[],"locations":[{"text":"\u003Cb\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003E\u003Ca class=\"mw-selflink selflink\"\u003EENS 52989\u003C/a\u003E - \u003Ca href=\"/Palo_Verde\" title=\"Palo Verde\"\u003EPalo Verde\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003ESeismic Monitoring Computer Out-Of-Service\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 52989 - Palo Verde\n","link":"","lat":33.386894444444444,"lon":-112.86263333333333,"icon":"/w/images/9/93/Arizona_Public_Service_icon.png"}],"imageoverlays":null} | |
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 %) |
Unit 3 | |
---|---|
Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |
WEEKMONTHYEARENS 557962022-03-19T20:06:00019 March 2022 20:06:00
[Table view]10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Technical Support Center (TSC) ENS 554442021-09-01T03:50:0001 September 2021 03:50:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Seismic Monitoring System ENS 542722019-09-12T01:24:00012 September 2019 01:24:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Main Steam Line Radiation Monitor Communication Failure ENS 535752018-08-31T07:00:00031 August 2018 07:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Unplanned Loss of Steam Line Monitor Channels ENS 535222018-07-23T07:00:00023 July 2018 07:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Unplanned Loss of Steam Line Monitor Channels ENS 532152018-02-16T04:53:00016 February 2018 04:53:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Automatic Reactor Trip Due to Low Departure from Nucleate Boiling Signal ENS 529892017-09-22T22:00:00022 September 2017 22:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Seismic Monitoring Computer Out-Of-Service ENS 522292016-09-09T01:56:0009 September 2016 01:56:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of the Seismic Monitoring System Computer ENS 510412015-05-04T10:20:0004 May 2015 10:20:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Seismic Monitoring System Out of Service ENS 496162013-12-08T15:00:0008 December 2013 15:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Assessment Due to Technical Support Center Uninterruptable Power Supply Planned Replacement ENS 488492013-03-25T17:30:00025 March 2013 17:30:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness One Alert Notification Siren Removed from Service for Planned Maintenance ENS 472742011-09-18T15:30:00018 September 2011 15:30:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Technical Support Center Out of Service Due to Planned Maintenance ENS 472682011-09-14T17:23:00014 September 2011 17:23:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Two Public Warning System Sirens ENS 463312010-10-14T16:15:00014 October 2010 16:15:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Emergency Sirens Will Be Taken Out of Service for Planned Maintenance ENS 461882010-08-18T14:42:00018 August 2010 14:42:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Several Public Warning System Sirens ENS 461402010-07-30T14:20:00030 July 2010 14:20:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Emergency Siren ENS 459682010-06-01T14:15:0001 June 2010 14:15:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Public Warning System Siren Out of Service ENS 454252009-10-11T11:50:00011 October 2009 11:50:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Reactor Water Level Indication Inoperable ENS 449242009-03-21T16:00:00021 March 2009 16:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Various Control Room Annunciators and Alarms Out of Service Due to Maintenance on Power Supply ENS 446922008-12-02T23:20:0002 December 2008 23:20:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of One (1) Emergency Siren ENS 446062008-10-28T16:00:00028 October 2008 16:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Maintenance on Public Prompt Notification System Emergency Sirens ENS 438242007-12-04T14:00:0004 December 2007 14:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness, 10 CFR 50.72(b)(3)(xii), Transport of a Contaminated Person Offsite Offsite Notification Due to Potential Loss of Three Sirens ENS 427012006-07-12T14:30:00012 July 2006 14:30:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness One Siren in Ep Zone Is Out of Service ENS 419412005-08-23T20:49:00023 August 2005 20:49:00 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 Two Emergency Sirens Inoperable ENS 419122005-08-11T15:45:00011 August 2005 15:45:00 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 One Emergency Preparedness Siren Out of Service ENS 418742005-07-26T23:35:00026 July 2005 23:35:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Inoperable Single Emergency Siren ENS 418102005-06-29T11:43:00029 June 2005 11:43:00 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 Evacuation Siren Inoperable ENS 414862005-03-13T01:45:00013 March 2005 01:45:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Operability of One Emergency Evacuation Siren ENS 414662005-03-07T15:10:0007 March 2005 15:10:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Two Emergency Sirens Inoperable ENS 414512005-02-28T21:57:00028 February 2005 21:57:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Major Loss of Siren Coverage within the Emergency Planning Zone 2022-03-19T20:06:00 | |