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At 0851 (EDT) on October 28, 2016, Divisio … At 0851 (EDT) on October 28, 2016, Division 1 RHR was started in shutdown cooling (SDC) mode of operation. Prior to starting the RHR system, the Alternate Decay Heat Removal (ADHR) system was maintaining RPV and Spent Fuel Pool temperature.</br>At 0924 on October 28, 2016, RHR (pump A) tripped due to RHR-MOV-17 (SDC suction valve) closing. This is considered to be an event or condition that could have prevented fulfillment of a safety function, and is reportable under 10 CFR 50.72(b)(3)(v)(B). RHR SDC subsystem A was declared inoperable. CNS (Cooper Nuclear Station) entered LCO 3.9.7, Condition A - Required Action A.1: Verify an alternate method of decay heat removal is available within 1 hour and once per 24 hours thereafter; Condition C - Required Action C.1: Verify reactor coolant circulation by an alternate method within 1 hour from discovery of no reactor coolant circulation and once per 12 hours thereafter, and Required Action C.2: Monitor reactor coolant temperature hourly. All LCO conditions specified have been met.</br>ADHR remained in service throughout the event and the plant remained aligned for natural circulation. Spent fuel pool weir temperature monitoring was commenced to verify natural circulation. No increase in RPV (reactor pressure vessel) temperature has been observed. There was no impact to plant operations.</br>Initial investigation indicates that installation of PCIS relay K27 during a maintenance activity physically agitated the adjacent relay, K30, which actuated and caused RHR-MOV-17 to close.</br>The NRC Resident Inspectors have been informed.RC Resident Inspectors have been informed. +
14:24:00, 28 October 2016 +
52,327 +
17:14:00, 28 October 2016 +
14:24:00, 28 October 2016 +
At 0851 (EDT) on October 28, 2016, Divisio … At 0851 (EDT) on October 28, 2016, Division 1 RHR was started in shutdown cooling (SDC) mode of operation. Prior to starting the RHR system, the Alternate Decay Heat Removal (ADHR) system was maintaining RPV and Spent Fuel Pool temperature.</br>At 0924 on October 28, 2016, RHR (pump A) tripped due to RHR-MOV-17 (SDC suction valve) closing. This is considered to be an event or condition that could have prevented fulfillment of a safety function, and is reportable under 10 CFR 50.72(b)(3)(v)(B). RHR SDC subsystem A was declared inoperable. CNS (Cooper Nuclear Station) entered LCO 3.9.7, Condition A - Required Action A.1: Verify an alternate method of decay heat removal is available within 1 hour and once per 24 hours thereafter; Condition C - Required Action C.1: Verify reactor coolant circulation by an alternate method within 1 hour from discovery of no reactor coolant circulation and once per 12 hours thereafter, and Required Action C.2: Monitor reactor coolant temperature hourly. All LCO conditions specified have been met.</br>ADHR remained in service throughout the event and the plant remained aligned for natural circulation. Spent fuel pool weir temperature monitoring was commenced to verify natural circulation. No increase in RPV (reactor pressure vessel) temperature has been observed. There was no impact to plant operations.</br>Initial investigation indicates that installation of PCIS relay K27 during a maintenance activity physically agitated the adjacent relay, K30, which actuated and caused RHR-MOV-17 to close.</br>The NRC Resident Inspectors have been informed.RC Resident Inspectors have been informed. +
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00:00:00, 28 October 2016 +
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