ENS 52004
ENS Event | |
|---|---|
22:33 Jun 13, 2016 | |
| Title | Alert Sirens Failed to Rotate |
| Event Description | At 1845 CDT on June 13, 2016, TVA Corporate Emergency Preparedness notified the Shift Manager at Browns Ferry Nuclear Plant that eight of the BFN [Browns Ferry Nuclear] Alert & Notification Sirens (19, 39, 55, 59, 60, 61, 69, 95) failed to rotate. The sirens were activated at 0915 CDT. Post sounding siren feedback indicated thirteen sirens that failed to rotate. BFN EP [Emergency Preparedness] Senior Instrument Mechanics were dispatched to inspect the thirteen sirens and determined, through field inspections that only eight sirens would not rotate. The field inspection was completed and communicated to Corporate Emergency Preparedness at 1733 CDT.
Per NPG-SPP-03.5.1, the affected sirens which were lost affect 25.1 percent of the Emergency Planning Zone (EPZ) population and the sirens are not expected to be returned to service within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Per NPG-SPP-03.5.1, a Loss of Alert and Notification System Capability exists when there is an unplanned or planned loss of primary Alert and Notification System (ANS) equipment for greater than one hour resulting in a loss of capability to alert 25 percent or more of the total Emergency Planning Zone (EPZ) population and either the Federal Emergency Management Agency (FEMA) approved backup alerting method cannot be implemented for the area affected by the lost primary ANS equipment OR the primary ANS equipment is not expected to be returned to service within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. TVA Corporate Emergency Preparedness is redirecting a team from Watts Bar Nuclear Plant to commence repairs on Wednesday 6/15/2016. This 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> notification is being made per the reporting requirements specified by 10 CFR 50.72(b)(3)xiii. The NRC Resident Inspector has been notified. This event has been entered in the Corrective Action Program.
The licensee is retracting this event notification. Upon further evaluation using siren modeling software, back-up route alerting was deemed unnecessary since the overlap from neighboring sirens provided the required minimum siren coverage over all populated areas within the EPZ. The TVA siren system provides significant acoustic overlap that is not completely accounted for in the population factors used to initially determine the impacted population for the purposes of reportability. During the event, BFN remained capable of providing adequate siren coverage, and the loss of ANS equipment impacted less than 25 percent of the population within the EPZ. Therefore, this was not a reportable event. The NRC Resident Inspector has been notified. Notified the RII RDO (Seymour). |
| Where | |
|---|---|
Browns Ferry  Alabama (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | |
| Time - Person (Reporting Time:+-0.33 h-0.0138 days <br />-0.00196 weeks <br />-4.52034e-4 months <br />) | |
| Opened: | Andrew D. Mitchell 22:13 Jun 13, 2016 |
| NRC Officer: | Daniel Mills |
| Last Updated: | Jul 8, 2016 |
| 52004 - 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 52004\u003C/a\u003E - \u003Ca href=\"/Browns_Ferry\" title=\"Browns Ferry\"\u003EBrowns Ferry\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EAlert Sirens Failed to Rotate\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 52004 - Browns Ferry\n","link":"","lat":34.70418333333333,"lon":-87.11844722222222,"icon":"/w/images/c/ce/Tennessee_Valley_Authority_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 543822019-11-12T12:00:00012 November 2019 12:00:00
[Table view]10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Emergency Operations Facility Out of Service ENS 542782019-09-13T09:27:00013 September 2019 09:27:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness En Revision Imported Date 9/17/2019 ENS 520042016-06-13T22:33:00013 June 2016 22:33:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Alert Sirens Failed to Rotate ENS 494552013-10-19T22:05:00019 October 2013 22:05:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Partial Loss of Offsite Communications Due to a Blown Fuse ENS 488232013-03-14T23:00:00014 March 2013 23:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Partial Loss of Offsite Communications ENS 483272012-09-20T17:40:00020 September 2012 17:40:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Emergency Assessment Capability Due to Inoperable Seismic Monitoring Instrumentation ENS 471242011-08-04T13:35:0004 August 2011 13:35:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Power to Emergency Sirens Due to Weather ENS 469862011-06-25T21:15:00025 June 2011 21:15:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Meteorological Monitoring Instrumentation Inoperable Due to Loss of Power ENS 468792011-05-24T14:18:00024 May 2011 14:18:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Power to Thirty-Two Emergency Sirens ENS 467932011-04-27T22:01:00027 April 2011 22:01:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Notification of Unusual Event Due to Loss of Offsite Power ENS 444712008-09-07T22:20:0007 September 2008 22:20:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Partial Loss of Offsite Communication Capability Caused by an Unplanned Power Outage ENS 442322008-05-21T20:15:00021 May 2008 20:15:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Control Room Phone Communications 2019-09-13T09:27:00 | |