Event Notification Report for March 25, 2021
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
03/24/2021 - 03/25/2021
EVENT NUMBERS
55154
55154
Power Reactor
Event Number: 55154
Facility: River Bend
Region: 4 State: LA
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: Thong Le
HQ OPS Officer: Thomas Herrity
Region: 4 State: LA
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: Thong Le
HQ OPS Officer: Thomas Herrity
Notification Date: 03/25/2021
Notification Time: 13:37 [ET]
Event Date: 03/25/2021
Event Time: 09:18 [CDT]
Last Update Date: 03/25/2021
Notification Time: 13:37 [ET]
Event Date: 03/25/2021
Event Time: 09:18 [CDT]
Last Update Date: 03/25/2021
Emergency Class: Non Emergency
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS Actuation - Critical 50.72(b)(3)(iv)(A) - Valid Specif Sys Actuation
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS Actuation - Critical 50.72(b)(3)(iv)(A) - Valid Specif Sys Actuation
Person (Organization):
GREG WERNER (R4DO)
GREG WERNER (R4DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | M/R | Y | 80 | Power Operation | 0 | Hot Shutdown |
EN Revision Imported Date: 4/20/2021
EN Revision Text: MANUAL REACTOR TRIP DUE TO LOWERING CONDENSER VACUUM
"On March 25, 2021 at 0901 CDT, River Bend Station Unit 1 (RBS) was operating at 93 [percent] reactor power (limited by 100 [percent] recirculation flow) when condenser vacuum began to lower due to ARC-AOV1A, Steam Jet Air Ejector Suction Valve, going closed. At 0918 CDT, a manual reactor SCRAM was inserted at approximately 80 [percent] reactor power due to condenser vacuum continuing to lower. After the SCRAM, all systems responded as designed and condenser vacuum was restored by starting a mechanical vacuum pump. The cause of the Steam Jet Air Ejector Suction Valve closure is unknown at this time and being investigated. Currently RBS is stable, and pressure is being maintained using Turbine Bypass Valves. The Main Steam Isolation Valves remained opened throughout the event.
"This event is being reported under 10 CFR 50.72(b)(2)(iv)(B), as any event or condition that results in actuation of the Reactor Protection System (RPS) when the reactor is critical and 10 CFR 50.72 (b)(3)(iv)(A) Specified System Actuation as result of expected post SCRAM level 3 isolations.
"No radiological releases have occurred due to this event from the unit.
"NRC Resident Inspector has been notified of this event."
EN Revision Text: MANUAL REACTOR TRIP DUE TO LOWERING CONDENSER VACUUM
"On March 25, 2021 at 0901 CDT, River Bend Station Unit 1 (RBS) was operating at 93 [percent] reactor power (limited by 100 [percent] recirculation flow) when condenser vacuum began to lower due to ARC-AOV1A, Steam Jet Air Ejector Suction Valve, going closed. At 0918 CDT, a manual reactor SCRAM was inserted at approximately 80 [percent] reactor power due to condenser vacuum continuing to lower. After the SCRAM, all systems responded as designed and condenser vacuum was restored by starting a mechanical vacuum pump. The cause of the Steam Jet Air Ejector Suction Valve closure is unknown at this time and being investigated. Currently RBS is stable, and pressure is being maintained using Turbine Bypass Valves. The Main Steam Isolation Valves remained opened throughout the event.
"This event is being reported under 10 CFR 50.72(b)(2)(iv)(B), as any event or condition that results in actuation of the Reactor Protection System (RPS) when the reactor is critical and 10 CFR 50.72 (b)(3)(iv)(A) Specified System Actuation as result of expected post SCRAM level 3 isolations.
"No radiological releases have occurred due to this event from the unit.
"NRC Resident Inspector has been notified of this event."