Event Notification Report for February 15, 2025
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
02/14/2025 - 02/15/2025
EVENT NUMBERS
57551
57551
Power Reactor
Event Number: 57551
Facility: Grand Gulf
Region: 4 State: MS
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: Mike Riehl
HQ OPS Officer: Adam Koziol
Region: 4 State: MS
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: Mike Riehl
HQ OPS Officer: Adam Koziol
Notification Date: 02/16/2025
Notification Time: 03:09 [ET]
Event Date: 02/15/2025
Event Time: 22:40 [CST]
Last Update Date: 02/16/2025
Notification Time: 03:09 [ET]
Event Date: 02/15/2025
Event Time: 22:40 [CST]
Last Update Date: 02/16/2025
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):
Dixon, John (R4DO)
Dixon, John (R4DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | M/R | Y | 84 | Power Operation | 0 | Hot Shutdown |
MANUAL REACTOR SCRAM DUE TO DEGRADING CONDENSER VACUUM
The following information was provided by the licensee via phone and email:
"On February 15, 2025 at 2240 CST, Grand Gulf Nuclear Station (GGNS) was operating in mode 1 at 84 percent reactor power when a [manual] reactor protection system (RPS) actuation (scram) occurred due to degrading condenser vacuum. All control rods inserted, there were no complications, and all plant systems responded as designed. Immediately after the scram, an expected reactor water level 3 isolation signal was received.
"Reactor pressure is being maintained via the main turbine bypass valves. Reactor level is being maintained via condensate and main feedwater. GGNS is currently in mode 3. No radiological releases have occurred due to this event.
"This event is being reported under 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A), as an event or condition that results in actuation of the RPS when the reactor is critical and as a specified system actuation due to the expected reactor water level 3 isolation signal immediately following the reactor scram.
"The NRC Senior Resident Inspector has been notified."
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
The loss of condenser vacuum was due to loss of power to the seal steam controller.
The following information was provided by the licensee via phone and email:
"On February 15, 2025 at 2240 CST, Grand Gulf Nuclear Station (GGNS) was operating in mode 1 at 84 percent reactor power when a [manual] reactor protection system (RPS) actuation (scram) occurred due to degrading condenser vacuum. All control rods inserted, there were no complications, and all plant systems responded as designed. Immediately after the scram, an expected reactor water level 3 isolation signal was received.
"Reactor pressure is being maintained via the main turbine bypass valves. Reactor level is being maintained via condensate and main feedwater. GGNS is currently in mode 3. No radiological releases have occurred due to this event.
"This event is being reported under 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A), as an event or condition that results in actuation of the RPS when the reactor is critical and as a specified system actuation due to the expected reactor water level 3 isolation signal immediately following the reactor scram.
"The NRC Senior Resident Inspector has been notified."
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
The loss of condenser vacuum was due to loss of power to the seal steam controller.