ENS 50853
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ENS Event | |
|---|---|
18:05 Feb 27, 2015 | |
| Title | Emergency Notification System and Health Physics Network Telephone Lines Out of Service |
| Event Description | On February 27, 2015, from 1305 to 1323 [EST], a loss of the ENS [Emergency Notification System] communication line, the HPN [Health Physics Network] line, and the other communication systems that the MCR [Main Control Room] operators use as part of the emergency plan occurred at TVA Sequoyah Units 1 and 2. A loss of these systems was experienced when transferring from a backup generator to an uninterruptible power supply (UPS) during fueling of the backup generator. Earlier in the day the normal power supply to the two (2) plant communications buildings was deenergized due to an unrelated electrical issue and backup diesel generators were supplying power to the buildings. While refueling one of the backup generators, the power supply was transferred to the UPS for personal safety reasons, however, the load on the UPS was greater than its capacity and its output [breaker] tripped.
This loss of communications was corrected in approximately 18 minutes once the fuel tank was filled and the generator was started. Phone line capability has been restored and verified to be functional. Sequoyah is currently investigating why the load was greater than the UPS capacity. The radiological emergency plan (REP) was reviewed and other acceptable methods for communications were available. There were no personnel injuries as a result of this event and no impact on plant operations. Both units remain at 100% power. The NRC Resident Inspector has been notified. This notification is being made in accordance with 10CFR50.72(b)(3)(xiii) due to the loss of communications capability which includes events that would significantly impair the ability of the licensee to implement the functions of its emergency plans if an emergency were to occur. |
| Where | |
|---|---|
Sequoyah  Tennessee (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | |
| Time - Person (Reporting Time:+-1.02 h-0.0425 days <br />-0.00607 weeks <br />-0.0014 months <br />) | |
| Opened: | Sam Nakamine 17:04 Feb 27, 2015 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Feb 27, 2015 |
| 50853 - 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 558672022-04-29T03:38:00029 April 2022 03:38:00
[Table view]10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Assessment Capability ENS 557422022-02-16T16:28:00016 February 2022 16:28:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Offsite Communication Capability ENS 549772020-11-01T09:56:0001 November 2020 09:56:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Seismic Assessment Instrumentation ENS 543802019-11-12T12:00:00012 November 2019 12:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Emergency Operations Facility Out of Service ENS 542762019-09-13T09:27:00013 September 2019 09:27:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness En Revision Imported Date 9/17/2019 ENS 521722016-08-11T14:15:00011 August 2016 14:15:00 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 Control Room Emergency Ventilation System Declared Inoperable ENS 508532015-02-27T18:05:00027 February 2015 18:05:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Emergency Notification System and Health Physics Network Telephone Lines Out of Service ENS 467902011-04-27T14:30:00027 April 2011 14:30:00 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 Loss of Emergency Sirens Due to Loss of Electric Power ENS 453702009-09-20T22:26:00020 September 2009 22:26:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Major Loss of Communications Due to Lightning Strike ENS 435432007-08-01T16:00:0001 August 2007 16:00:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness 77 Out of 108 Prompt Notification System Sirens Failed Their Monthly Test ENS 428572006-09-24T08:30:00024 September 2006 08:30:00 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Emergency Notification System and Commercial Telephone Line Problems 2022-04-29T03:38:00 | |
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