ENS 46588
ENS Event | |
|---|---|
14:30 Feb 2, 2011 | |
| Title | Partial Loss of Prompt Notification System (Pns) Emergency Sirens Due to a Loss of Power |
| Event Description | At approximately 0830 [CST] on 2/2/2011, eleven (11) of thirty-two (32) STP Prompt Notification System (PNS) sirens were not operable due to loss of power. The sirens were subsequently polled at approximately 0909 [CST] and all sirens except 3 were operable. The loss of power was caused by rolling outages due to unusually severe cold weather. ERCOT issued an order requiring load shedding to maintain a steady state system frequency of 59.8 Hertz (Hz) on the grid. The outages were suspended at 1400 hrs but rolling outages could continue through the end of the week potentially affecting the sirens. All 32 sirens were likely affected during the outages for some un-quantified period of time. Continuous polling of the sirens was not performed or advisable since polling depletes the batteries which could affect the operability of the sirens.
STPNOC [South Texas Project Nuclear Operating Company] has notified Matagorda County Sheriff Department. Compensatory measures have been verified to be available should the Prompt Notification System be needed. This consists of using Local Law Enforcement Personnel for 'Route Alerting' of the affected areas of the Emergency Planning Zone (EPZ). Matagorda County Emergency Management has verified that the Matagorda County Sheriffs Department is on standby for Route Alerting. STPNOC is currently transitioning to new sirens. While the new sirens are not currently credited in the STP Emergency Plan, we have received final FEMA approval. All of the new battery-backed sirens were tested and verified to remain operable and capable of notifying the population in the EPZ. This notification is being made under 10 CFR 50.72(b)(3)(xiii) due to a significant loss of the offsite Prompt Notification System. It is possible that rolling outages may recommence in the next several days. The licensee informed the NRC Resident Inspector and the offsite agencies identified above. |
| Where | |
|---|---|
South Texas  Texas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | |
| Time - Person (Reporting Time:+2.73 h0.114 days <br />0.0162 weeks <br />0.00374 months <br />) | |
| Opened: | Ron Gibbs 17:14 Feb 2, 2011 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Feb 2, 2011 |
| 46588 - 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 542842019-09-18T12:50:00018 September 2019 12:50:00
[Table view]10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Communication with Emergency Operations Facility ENS 541452019-07-03T15:26:0003 July 2019 15:26:00 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 Due to Radio Transmitter Out of Service ENS 536562018-10-09T05:00:0009 October 2018 05:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Unplanned Loss of Emergency Response Equipment ENS 531182017-12-12T23:57:00012 December 2017 23:57:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Unplanned Loss of Emergency Response Equipment ENS 527752017-05-30T14:29:00030 May 2017 14:29:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Emergency Operations Facility Integrated Computer System Data for Planned Maintenance ENS 511152015-06-01T15:26:0001 June 2015 15:26:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Unit 2 Ventilation Radiation Monitor Operability ENS 484482012-10-27T19:15:00027 October 2012 19:15:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Offsite Communications ENS 465882011-02-02T14:30:0002 February 2011 14:30:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Partial Loss of Prompt Notification System (Pns) Emergency Sirens Due to a Loss of Power ENS 435952007-08-25T12:30:00025 August 2007 12:30:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Erds System and Portions of Plant Computer Out of Service for Planned Maintenance Outage ENS 430862007-01-10T18:35:00010 January 2007 18:35:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Offsite Landline Communications Capability Due to Cut Fiber Optic Cable ENS 425792006-05-16T14:45:00016 May 2006 14:45:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Disruption of Incoming and Outgoing Telephone Communciation Capability 2019-09-18T12:50:00 | |