Event Notification Report for July 30, 2025
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
07/29/2025 - 07/30/2025
Power Reactor
Event Number: 57841
Facility: Dresden
Region: 3 State: IL
Unit: [2] [3] []
RX Type: [2] GE-3,[3] GE-3
NRC Notified By: Bora Tuncer
HQ OPS Officer: Jordan Wingate
Region: 3 State: IL
Unit: [2] [3] []
RX Type: [2] GE-3,[3] GE-3
NRC Notified By: Bora Tuncer
HQ OPS Officer: Jordan Wingate
Notification Date: 07/31/2025
Notification Time: 00:41 [ET]
Event Date: 07/30/2025
Event Time: 16:45 [CDT]
Last Update Date: 07/31/2025
Notification Time: 00:41 [ET]
Event Date: 07/30/2025
Event Time: 16:45 [CDT]
Last Update Date: 07/31/2025
Emergency Class: Non Emergency
10 CFR Section:
50.72(b)(3)(v)(B) - Pot RHR Inop
10 CFR Section:
50.72(b)(3)(v)(B) - Pot RHR Inop
Person (Organization):
Hills, David (R3DO)
Hills, David (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
| 3 | N | Y | 100 | Power Operation | 100 | Power Operation |
POTENTIAL INOPERABILITY OF RESIDUAL HEAT REMOVAL (RHR) SYSTEM
The following information was provided by the licensee via phone and email:
"At 1645 CDT on July 30, 2025, it was discovered that the single train of the ultimate heat sink was inoperable. Due to this inoperability, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(B).
"There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
The proximal cause of the inoperability was due to a buildup of grasses in the crib house from the river. Operators were able to clear the crib house bar rack intake and restore operability within eight minutes.
The following information was provided by the licensee via phone and email:
"At 1645 CDT on July 30, 2025, it was discovered that the single train of the ultimate heat sink was inoperable. Due to this inoperability, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(B).
"There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
The proximal cause of the inoperability was due to a buildup of grasses in the crib house from the river. Operators were able to clear the crib house bar rack intake and restore operability within eight minutes.
Power Reactor
Event Number: 57839
Facility: Braidwood
Region: 3 State: IL
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: Matthew McHale
HQ OPS Officer: Kerby Scales
Region: 3 State: IL
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: Matthew McHale
HQ OPS Officer: Kerby Scales
Notification Date: 07/30/2025
Notification Time: 17:20 [ET]
Event Date: 07/30/2025
Event Time: 12:30 [CDT]
Last Update Date: 07/30/2025
Notification Time: 17:20 [ET]
Event Date: 07/30/2025
Event Time: 12:30 [CDT]
Last Update Date: 07/30/2025
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):
Hills, David (R3DO)
Hills, David (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | A/R | Y | 100 | Power Operation | 0 | Hot Standby |
AUTOMATIC REACTOR TRIP
The following information was provided by the licensee via phone and email:
"On July 30, 2025, at 1230 CDT, with Unit 1 in mode 1 at 100 percent power, the reactor automatically tripped due to an over temperature delta 'T' reactor protection system actuation while critical. This event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B).
"Actuation of the auxiliary feedwater [system] occurred during the reactor trip response. The cause of the auxiliary feedwater auto-start was a LO-2 steam generator water level. The 1A and 1B auxiliary feedwater pumps started as designed when the LO-2 steam generator water level signal was received. This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the auxiliary feedwater system. Operators responded using procedures 1BwEP-0 and 1BwEP ES-0.1 to stabilize the unit in mode 3.
"Decay heat is being removed by discharging steam to the main condenser using the main steam dump valves. Unit 2 is not affected. All systems responded as expected with the exception of steam pressure channel 1Pl-545A and steam flow channel 1Fl-523A, which both failed high during the lightning storm and subsequent transient. Actions per 1BwOA lnstrument-2 are in progress to address these failures.
"There was no impact on the health and safety of the public or plant personnel.
"The NRC Resident Inspector has been notified."
The following information was provided by the licensee via phone and email:
"On July 30, 2025, at 1230 CDT, with Unit 1 in mode 1 at 100 percent power, the reactor automatically tripped due to an over temperature delta 'T' reactor protection system actuation while critical. This event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B).
"Actuation of the auxiliary feedwater [system] occurred during the reactor trip response. The cause of the auxiliary feedwater auto-start was a LO-2 steam generator water level. The 1A and 1B auxiliary feedwater pumps started as designed when the LO-2 steam generator water level signal was received. This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the auxiliary feedwater system. Operators responded using procedures 1BwEP-0 and 1BwEP ES-0.1 to stabilize the unit in mode 3.
"Decay heat is being removed by discharging steam to the main condenser using the main steam dump valves. Unit 2 is not affected. All systems responded as expected with the exception of steam pressure channel 1Pl-545A and steam flow channel 1Fl-523A, which both failed high during the lightning storm and subsequent transient. Actions per 1BwOA lnstrument-2 are in progress to address these failures.
"There was no impact on the health and safety of the public or plant personnel.
"The NRC Resident Inspector has been notified."