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Home NRC Library Document Collections Events, Reports Associated with Event Notification Reports 2025

Event Notification Report for May 06, 2025

U.S. Nuclear Regulatory Commission
Operations Center

EVENT REPORTS FOR
05/05/2025 - 05/06/2025

EVENT NUMBERS
57689 57691
Power Reactor
Event Number: 57689
Facility: Callaway
Region: 4     State: MO
Unit: [1] [] []
RX Type: [1] W-4-LP
NRC Notified By: Zach Milligan
HQ OPS Officer: Ian Howard
Notification Date: 05/04/2025
Notification Time: 21:30 [ET]
Event Date: 05/04/2025
Event Time: 12:30 [CDT]
Last Update Date: 05/04/2025
Emergency Class: Non Emergency
10 CFR Section:
50.72(b)(3)(v)(D) - Accident Mitigation
Person (Organization):
Agrawal, Ami (R4DO)
Power Reactor Unit Info
Unit SCRAM Code RX Crit Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N N 0 0
Event Text
BOTH TRAINS OF EMERGENCY CORE COOLING SYSTEM INOPERABLE

The following information was provided by the licensee via phone and email:

"On May 4, 2025, with the plant in mode 4 during restart from a refueling outage, operators were flushing the chemical volume and control system [CVCS] `B' train mixed bed demineralizers, with makeup [water] from the refueling water storage tank (RWST). During the evolution at 1230 CDT, it was discovered that the borated water level in the RWST had been inadvertently lowered to less than the technical specification (TS) limit of 394,000 gallons. Under TS 3.5.4, `Refueling Water Storage Tank (RWST),' surveillance requirement (SR) 3.5.4.2 requires verifying that the RWST borated water volume is [greater than or equal to] 394,000 gallons (93.7 percent level). The minimum level (volume) reached in the tank during the flushing operation was 93 percent.

"Upon discovery of the lowered level in the RWST, the flushing activity was terminated, and water level in the RWST was restored to above the TS limit by 1427.

"The RWST supplies borated water to the CVCS during abnormal operating conditions, and to the emergency core cooling system (ECCS) and the containment spray system during accident conditions. The RWST supplies both trains of the ECCS and the containment spray system through a common suction supply header during the injection phase of a loss of coolant accident recovery. During mode 4, in accordance with TS 3.5.3, `ECCS - Shutdown,' only one ECCS train is required to be operable.

"With the RWST declared inoperable, the one required ECCS train in mode 4 was not supported. Therefore, the identified condition is being reported pursuant to 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident."

The NRC Resident Inspector was notified.


Power Reactor
Event Number: 57691
Facility: Hatch
Region: 2     State: GA
Unit: [1] [] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: Hugh Garret Crosby
HQ OPS Officer: Ian Howard
Notification Date: 05/05/2025
Notification Time: 15:26 [ET]
Event Date: 03/14/2025
Event Time: 15:23 [EDT]
Last Update Date: 05/05/2025
Emergency Class: Non Emergency
10 CFR Section:
50.73(a)(1) - Invalid Specif System Actuation
Person (Organization):
Pearson, Laura (R2DO)
Power Reactor Unit Info
Unit SCRAM Code RX Crit Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N Y 100 100
Event Text
60-DAY OPTIONAL TELEPHONIC NOTIFICATION FOR AN INVALID CONTAINMENT ISOLATION

The following information was provided by the licensee via phone and email:

"On March 14, 2025, at 1523 EST, while Unit 1 was operating at 99.5 percent power in mode 1, the unit experienced a loss of the 24/48V DC bus (division 2) due to a failed battery charger. The 24/48V DC bus was restored by installing a temporary charger.

"This event is reportable per 10 CFR 50.73(a)(2)(iv)(A) because it was not part of a pre-planned sequence and resulted in the invalid, partial actuation of containment isolation valves (CIVs) in both the primary containment and secondary containment systems, with all systems responding normally.

"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."