Event Notification Report for February 17, 2021
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
02/16/2021 - 02/17/2021
Power Reactor
Event Number: 55191
Facility: Brunswick
Region: 2 State: NC
Unit: [2] [] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: Richard Barrett
HQ OPS Officer: Brian Lin
Region: 2 State: NC
Unit: [2] [] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: Richard Barrett
HQ OPS Officer: Brian Lin
Notification Date: 04/14/2021
Notification Time: 13:00 [ET]
Event Date: 02/17/2021
Event Time: 15:07 [EDT]
Last Update Date: 04/14/2021
Notification Time: 13:00 [ET]
Event Date: 02/17/2021
Event Time: 15:07 [EDT]
Last Update Date: 04/14/2021
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 (R2)
MILLER, MARK (R2)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
EN Revision Imported Date: 5/14/2021
EN Revision Text: INVALID ACTUATION OF CONTAINMENT ISOLATION VALVES
"This 60-day optional telephone notification is being made in lieu of an LER submittal as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B).
"At approximately 1507 EDT on February 17, 2021, during performance of isolation logic periodic testing associated with Primary Containment Isolation System Groups 2 and 6, an invalid actuation of Group 6 Primary Containment Isolation Valves (PCIVs) (i.e., Containment Atmospheric Control/Monitoring and Post Accident Sampling isolation valves) occurred. The Group 6 isolation signal resulted from the reactor building ventilation radiation monitor `B' Channel exceeding the setpoint value. This condition likely resulted from the radiation monitor electronics being impacted by humidity levels, which exceeded the instrument design requirements that developed in the area over time as a result of the Unit 2 reactor building ventilation being secured per the test procedure. The `A' Channel, located in the same plenum, remained steady and below the setpoint value through the entire event. This, along with readings made by a Radiation Protection Technician, confirmed that there was no actual high radiation condition in the reactor building exhaust. Upon returning Unit 2 reactor building ventilation to service, the `B' Channel readings returned to be consistent with the `A' Channel.
"The PCIVs functioned successfully and the actuation was complete. The actuation was not initiated in response to actual plant conditions, it was not an intentional manual initiation, and there were no parameters satisfying the requirements for initiation of the system. Therefore, this event has been determined to be an invalid actuation.
"This event did not result in any adverse impact to the health and safety of the public.
"The NRC Resident Inspector was notified."
EN Revision Text: INVALID ACTUATION OF CONTAINMENT ISOLATION VALVES
"This 60-day optional telephone notification is being made in lieu of an LER submittal as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B).
"At approximately 1507 EDT on February 17, 2021, during performance of isolation logic periodic testing associated with Primary Containment Isolation System Groups 2 and 6, an invalid actuation of Group 6 Primary Containment Isolation Valves (PCIVs) (i.e., Containment Atmospheric Control/Monitoring and Post Accident Sampling isolation valves) occurred. The Group 6 isolation signal resulted from the reactor building ventilation radiation monitor `B' Channel exceeding the setpoint value. This condition likely resulted from the radiation monitor electronics being impacted by humidity levels, which exceeded the instrument design requirements that developed in the area over time as a result of the Unit 2 reactor building ventilation being secured per the test procedure. The `A' Channel, located in the same plenum, remained steady and below the setpoint value through the entire event. This, along with readings made by a Radiation Protection Technician, confirmed that there was no actual high radiation condition in the reactor building exhaust. Upon returning Unit 2 reactor building ventilation to service, the `B' Channel readings returned to be consistent with the `A' Channel.
"The PCIVs functioned successfully and the actuation was complete. The actuation was not initiated in response to actual plant conditions, it was not an intentional manual initiation, and there were no parameters satisfying the requirements for initiation of the system. Therefore, this event has been determined to be an invalid actuation.
"This event did not result in any adverse impact to the health and safety of the public.
"The NRC Resident Inspector was notified."
Power Reactor
Event Number: 55188
Facility: Hatch
Region: 2 State: GA
Unit: [2] [] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: Kevin Carter
HQ OPS Officer: Kerby Scales
Region: 2 State: GA
Unit: [2] [] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: Kevin Carter
HQ OPS Officer: Kerby Scales
Notification Date: 04/12/2021
Notification Time: 09:17 [ET]
Event Date: 02/17/2021
Event Time: 23:20 [EDT]
Last Update Date: 04/12/2021
Notification Time: 09:17 [ET]
Event Date: 02/17/2021
Event Time: 23:20 [EDT]
Last Update Date: 04/12/2021
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 (R2)
MILLER, MARK (R2)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 0 | Cold Shutdown | 94 | Power Operation |
EN Revision Imported Date: 5/12/2021
EN Revision Text: AUTOMATIC ACTUATION OF GROUP 2 CONTAINMENT ISOLATION LOGIC
"At 2320 EST on 02/17/2021, with Unit 2 in Mode 5 at zero percent power, an actuation of the Group 2 containment isolation logic occurred on the inboard valves. The reason for the actuation was most likely due to air entrapment in reactor water level sensing lines following maintenance. Group 2 inboard isolation valves in the drywell floor and equipment drain system and the fission product monitor system automatically isolated as designed. As a corrective action, the variable leg and reference leg of the instrumentation were backfilled with water to ensure all air was removed from the line.
"This event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A) as an event that results in an invalid actuation of the Group 2 containment isolation system.
"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
EN Revision Text: AUTOMATIC ACTUATION OF GROUP 2 CONTAINMENT ISOLATION LOGIC
"At 2320 EST on 02/17/2021, with Unit 2 in Mode 5 at zero percent power, an actuation of the Group 2 containment isolation logic occurred on the inboard valves. The reason for the actuation was most likely due to air entrapment in reactor water level sensing lines following maintenance. Group 2 inboard isolation valves in the drywell floor and equipment drain system and the fission product monitor system automatically isolated as designed. As a corrective action, the variable leg and reference leg of the instrumentation were backfilled with water to ensure all air was removed from the line.
"This event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A) as an event that results in an invalid actuation of the Group 2 containment isolation system.
"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."