Event Notification Report for September 14, 2025
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
09/13/2025 - 09/14/2025
EVENT NUMBERS
57929
57929
Power Reactor
Event Number: 57929
Facility: Comanche Peak
Region: 4 State: TX
Unit: [2] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: Victor Alanis
HQ OPS Officer: Ernest West
Region: 4 State: TX
Unit: [2] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: Victor Alanis
HQ OPS Officer: Ernest West
Notification Date: 09/15/2025
Notification Time: 00:16 [ET]
Event Date: 09/14/2025
Event Time: 20:20 [CDT]
Last Update Date: 09/15/2025
Notification Time: 00:16 [ET]
Event Date: 09/14/2025
Event Time: 20:20 [CDT]
Last Update Date: 09/15/2025
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):
Agrawal, Ami (R4DO)
Agrawal, Ami (R4DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | M/R | Y | 100 | Power Operation | 0 | Hot Standby |
MANUAL REACTOR TRIP
The following information was provided by the licensee via phone and email:
"At 2020 CDT [on 9/14/2025], [Comanche Peak] Unit 2 reactor was manually tripped due to a malfunction of the electro-hydraulic control (EHC) system on the main turbine. All auxiliary feedwater pumps started due to steam generator `Lo-Lo' levels post trip. This event is being reported in accordance with 10 CFR 50.72(b)(2)(iv)(B) for a reactor trip and 10 CFR 50.72(b)(3)(iv)(A) for an actuation of auxiliary feedwater. Unit 2 is being maintained in hot standby (mode 3) in accordance with integrated plant operating procedures. Decay heat is being rejected to the main condenser via the steam dump valves."
The NRC Resident Inspector was notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
Unit 1 was not affected. The cause of the malfunction of EHC is unknown and under investigation. All rods fully inserted upon the reactor being tripped.
The following information was provided by the licensee via phone and email:
"At 2020 CDT [on 9/14/2025], [Comanche Peak] Unit 2 reactor was manually tripped due to a malfunction of the electro-hydraulic control (EHC) system on the main turbine. All auxiliary feedwater pumps started due to steam generator `Lo-Lo' levels post trip. This event is being reported in accordance with 10 CFR 50.72(b)(2)(iv)(B) for a reactor trip and 10 CFR 50.72(b)(3)(iv)(A) for an actuation of auxiliary feedwater. Unit 2 is being maintained in hot standby (mode 3) in accordance with integrated plant operating procedures. Decay heat is being rejected to the main condenser via the steam dump valves."
The NRC Resident Inspector was notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
Unit 1 was not affected. The cause of the malfunction of EHC is unknown and under investigation. All rods fully inserted upon the reactor being tripped.