Event Notification Report for November 24, 2022
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
11/23/2022 - 11/24/2022
EVENT NUMBERS
56274
56274
Power Reactor
Event Number: 56274
Facility: Watts Bar
Region: 2 State: TN
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: Brian McIlnay
HQ OPS Officer: Bill Gott
Region: 2 State: TN
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: Brian McIlnay
HQ OPS Officer: Bill Gott
Notification Date: 12/15/2022
Notification Time: 12:52 [ET]
Event Date: 11/24/2022
Event Time: 16:21 [EST]
Last Update Date: 12/15/2022
Notification Time: 12:52 [ET]
Event Date: 11/24/2022
Event Time: 16:21 [EST]
Last Update Date: 12/15/2022
Emergency Class: Non Emergency
10 CFR Section:
50.73(a)(1) - Invalid Specif System Actuation
10 CFR Section:
50.73(a)(1) - Invalid Specif System Actuation
Person (Organization):
Miller, Mark (R2DO)
Miller, Mark (R2DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 100 | Power Operation |
60-DAY OPTIONAL TELEPHONIC NOTIFICATION OF INVALID ACTUATION OF CONTAINMENT VENTILATION ISOLATION VALVES
The following information was provided by the licensee via email:
"This 60-day telephone notification is being submitted in accordance with paragraphs 10 CFR 50.73(a)(1) and 50.73(a)(2)(iv)(A) to report an invalid Containment Ventilation Isolation (CVI) actuation at Watts Bar Nuclear Plant (WBN) Unit 1.
"On November 24, 2022, at 1621 Eastern Standard Time (EST), the Train B CVI actuated due to an invalid high radiation signal from 1-RM-90-131, Containment Purge Air Exhaust Monitor. Upon investigation, the high radiation signal was caused by a failed power supply. Corrective action included replacing the power supply, 1-RM-90-131 ratemeter, and restoring the system to service.
"Prior to and following the invalid high radiation alarm, all radiation monitors except 1-RM-90-131 were stable at their normal values; therefore, the CVI was invalid. Control room operators performed appropriate checks and confirmed that all required automatic actuations occurred as designed. This event has been entered into the corrective action program as Condition Report 1819098.
"The NRC Resident Inspector was notified."
The following information was provided by the licensee via email:
"This 60-day telephone notification is being submitted in accordance with paragraphs 10 CFR 50.73(a)(1) and 50.73(a)(2)(iv)(A) to report an invalid Containment Ventilation Isolation (CVI) actuation at Watts Bar Nuclear Plant (WBN) Unit 1.
"On November 24, 2022, at 1621 Eastern Standard Time (EST), the Train B CVI actuated due to an invalid high radiation signal from 1-RM-90-131, Containment Purge Air Exhaust Monitor. Upon investigation, the high radiation signal was caused by a failed power supply. Corrective action included replacing the power supply, 1-RM-90-131 ratemeter, and restoring the system to service.
"Prior to and following the invalid high radiation alarm, all radiation monitors except 1-RM-90-131 were stable at their normal values; therefore, the CVI was invalid. Control room operators performed appropriate checks and confirmed that all required automatic actuations occurred as designed. This event has been entered into the corrective action program as Condition Report 1819098.
"The NRC Resident Inspector was notified."