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The following information was provided by … The following information was provided by the licensee via phone and email:</br>At 1702 MST on August 14, 2022, a start-up transformer de-energized, resulting in a loss of power to the Unit 1 Train B 4.16 kV Class 1E Bus and the Unit 3 Train A 4.16 kV Class 1E Bus. The Unit 1 Train B Emergency Diesel Generator (EDG) and Unit 3 Train A EDG automatically started and energized their respective 4.16 kV Class 1E Buses. As a result of the loss of power on the Unit 1 Train B 4.16 kV Class 1E Bus, the B Auxiliary Feedwater Pump automatically started, as expected. The B Auxiliary Feedwater Pump was not needed for steam generator level control and no auxiliary feedwater valves repositioned. The B Auxiliary Feedwater Pump did not supply feedwater to the steam generators. </br>This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of emergency AC electrical power systems and an auxiliary feedwater system.</br>All systems operated as expected. Per the Emergency Plan, no classification was required due to the event. The 4.16 kV Class 1E Buses in Unit 2 were not affected by the de-energization of the start-up transformer since it was not aligned as normal power for Unit 2. Units 1, 2 and 3 remain in Mode 1 at 100% power.</br>The cause of the start-up transformer being de-energized is under investigation. No plant transient occurred as a result of this failure.</br>The NRC Resident Inspectors have been informed.RC Resident Inspectors have been informed. +
00:02:00, 15 August 2022 +
56,044 +
01:18:00, 15 August 2022 +
00:02:00, 15 August 2022 +
The following information was provided by … The following information was provided by the licensee via phone and email:</br>At 1702 MST on August 14, 2022, a start-up transformer de-energized, resulting in a loss of power to the Unit 1 Train B 4.16 kV Class 1E Bus and the Unit 3 Train A 4.16 kV Class 1E Bus. The Unit 1 Train B Emergency Diesel Generator (EDG) and Unit 3 Train A EDG automatically started and energized their respective 4.16 kV Class 1E Buses. As a result of the loss of power on the Unit 1 Train B 4.16 kV Class 1E Bus, the B Auxiliary Feedwater Pump automatically started, as expected. The B Auxiliary Feedwater Pump was not needed for steam generator level control and no auxiliary feedwater valves repositioned. The B Auxiliary Feedwater Pump did not supply feedwater to the steam generators. </br>This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of emergency AC electrical power systems and an auxiliary feedwater system.</br>All systems operated as expected. Per the Emergency Plan, no classification was required due to the event. The 4.16 kV Class 1E Buses in Unit 2 were not affected by the de-energization of the start-up transformer since it was not aligned as normal power for Unit 2. Units 1, 2 and 3 remain in Mode 1 at 100% power.</br>The cause of the start-up transformer being de-energized is under investigation. No plant transient occurred as a result of this failure.</br>The NRC Resident Inspectors have been informed.RC Resident Inspectors have been informed. +
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100 +
00:00:00, 15 August 2022 +
Modification date"Modification date" is a predefined property that corresponds to the date of the last modification of a subject and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
11:30:12, 17 August 2022 +
01:18:00, 15 August 2022 +
true +
false +
0.0529 d (1.27 hours, 0.00756 weeks, 0.00174 months) +
00:02:00, 15 August 2022 +
Valid Actuations of Unit 1 and Unit 3 Emergency Diesel Generators and Unit 1 Auxiliary Feedwater Pump +
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