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The following information was provided by … The following information was provided by the licensee via email:</br>At 1617 on 11/7/2023, Calvert Cliffs Unit 2 experienced an automatic trip from a Reactor Protection System (RPS) based on reactor trip bus under voltage (UV). At that time a loss of U-4000-22 caused a loss of 22, 23, and 24 4kV busses. This resulted in a loss of both motor generator (MG) sets causing the reactor trip bus UV condition. The loss of 22 and 23 4kV non-safety related busses resulted in a loss of main feedwater. Auxiliary feedwater (AFW) was manually initiated and is feeding both steam generators. The 2B diesel generator (DG) started and restored the 24 4kV safety related bus. Heat removal is via the normal turbine bypass valves to the main condenser.</br>RPS actuation is reportable under 10 CFR 50.72(b)(2)(iv)(B) - 4-hour report. </br>ESFAS actuation (2B DG start on UV) is reportable under 10CFR50.72(b)(3)(iv)(A) - 8-hour report. </br>ESFAS actuation (AFW manual initiation) is reportable under 10CFR50.72(b)(3)(iv)(A) - 8-hour report. </br>Site Senior NRC resident inspector has been notified.</br>The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:</br>Unit 1 was unaffected. Estimation of duration of shutdown is 24 hours.ation of duration of shutdown is 24 hours. +
21:17:00, 7 November 2023 +
56,839 +
18:42:00, 7 November 2023 +
21:17:00, 7 November 2023 +
The following information was provided by … The following information was provided by the licensee via email:</br>At 1617 on 11/7/2023, Calvert Cliffs Unit 2 experienced an automatic trip from a Reactor Protection System (RPS) based on reactor trip bus under voltage (UV). At that time a loss of U-4000-22 caused a loss of 22, 23, and 24 4kV busses. This resulted in a loss of both motor generator (MG) sets causing the reactor trip bus UV condition. The loss of 22 and 23 4kV non-safety related busses resulted in a loss of main feedwater. Auxiliary feedwater (AFW) was manually initiated and is feeding both steam generators. The 2B diesel generator (DG) started and restored the 24 4kV safety related bus. Heat removal is via the normal turbine bypass valves to the main condenser.</br>RPS actuation is reportable under 10 CFR 50.72(b)(2)(iv)(B) - 4-hour report. </br>ESFAS actuation (2B DG start on UV) is reportable under 10CFR50.72(b)(3)(iv)(A) - 8-hour report. </br>ESFAS actuation (AFW manual initiation) is reportable under 10CFR50.72(b)(3)(iv)(A) - 8-hour report. </br>Site Senior NRC resident inspector has been notified.</br>The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:</br>Unit 1 was unaffected. Estimation of duration of shutdown is 24 hours.ation of duration of shutdown is 24 hours. +
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