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On February 27, 2015, from 1305 to 1323 (E … 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.</br> </br>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.</br>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.gency plans if an emergency were to occur. +
18:05:00, 27 February 2015 +
50,853 +
17:04:00, 27 February 2015 +
18:05:00, 27 February 2015 +
On February 27, 2015, from 1305 to 1323 (E … 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.</br> </br>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.</br>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.gency plans if an emergency were to occur. +
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