Event Notification Report for August 11, 2023
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
08/10/2023 - 08/11/2023
Part 21
Event Number: 56789
Rep Org: DC COOK
Licensee: DC COOK
Region: 3
City: Bridgman State: MI
County:
License #:
Agreement: N
Docket:
NRC Notified By: Steve Mitchell
HQ OPS Officer: John Russell
Licensee: DC COOK
Region: 3
City: Bridgman State: MI
County:
License #:
Agreement: N
Docket:
NRC Notified By: Steve Mitchell
HQ OPS Officer: John Russell
Notification Date: 10/12/2023
Notification Time: 12:17 [ET]
Event Date: 08/11/2023
Event Time: 00:00 [EDT]
Last Update Date: 10/12/2023
Notification Time: 12:17 [ET]
Event Date: 08/11/2023
Event Time: 00:00 [EDT]
Last Update Date: 10/12/2023
Emergency Class: Non Emergency
10 CFR Section:
21.21(a)(2) - Interim Eval Of Deviation
10 CFR Section:
21.21(a)(2) - Interim Eval Of Deviation
Person (Organization):
Orth, Steve (R3DO)
Part 21/50.55 Reactors, - (EMAIL)
Orth, Steve (R3DO)
Part 21/50.55 Reactors, - (EMAIL)
PART 21 REPORT - EMERGENCY DIESEL GENERATOR DIGITAL REFERENCE UNIT PROBLEM
The following information was provided by the licensee via email:
"Donald C. Cook Nuclear Power Plant completed an internal Part 21 evaluation concerning an issue with an Emergency Diesel Generator (EDG) Digital Reference Unit (DRU) supplied by Engine Systems Incorporated (Appendix B Supplier for Woodward Governors). [On August 8, 2023,] a potential defect was identified [during a surveillance test] concerning a marginal solder joint on the DRU electronic circuit board that can result in a loss of continuity between the termination strip and the electronic board, causing a loss of setpoint output from the DRU to the Electronic Governor, and a subsequent loss of fuel to the EDG and inability to support any load. A formal failure analysis is ongoing at the time of this notification. A written notification will be provided within 30 days.
"Affected known plants include only Donald C. Cook Nuclear Power Plant Units 1 and 2 at the time of notification.
"The NRC Resident has been notified."
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
The EDG DRU was replaced after discovery of the potential defect and the EDG is currently operable.
The following information was provided by the licensee via email:
"Donald C. Cook Nuclear Power Plant completed an internal Part 21 evaluation concerning an issue with an Emergency Diesel Generator (EDG) Digital Reference Unit (DRU) supplied by Engine Systems Incorporated (Appendix B Supplier for Woodward Governors). [On August 8, 2023,] a potential defect was identified [during a surveillance test] concerning a marginal solder joint on the DRU electronic circuit board that can result in a loss of continuity between the termination strip and the electronic board, causing a loss of setpoint output from the DRU to the Electronic Governor, and a subsequent loss of fuel to the EDG and inability to support any load. A formal failure analysis is ongoing at the time of this notification. A written notification will be provided within 30 days.
"Affected known plants include only Donald C. Cook Nuclear Power Plant Units 1 and 2 at the time of notification.
"The NRC Resident has been notified."
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
The EDG DRU was replaced after discovery of the potential defect and the EDG is currently operable.
Power Reactor
Event Number: 56676
Facility: Quad Cities
Region: 3 State: IL
Unit: [2] [] []
RX Type: [1] GE-3,[2] GE-3
NRC Notified By: Gregg Hughes
HQ OPS Officer: Ernest West
Region: 3 State: IL
Unit: [2] [] []
RX Type: [1] GE-3,[2] GE-3
NRC Notified By: Gregg Hughes
HQ OPS Officer: Ernest West
Notification Date: 08/11/2023
Notification Time: 08:03 [ET]
Event Date: 08/11/2023
Event Time: 03:29 [CDT]
Last Update Date: 08/11/2023
Notification Time: 08:03 [ET]
Event Date: 08/11/2023
Event Time: 03:29 [CDT]
Last Update Date: 08/11/2023
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):
Peterson, Hironori (R3DO)
Peterson, Hironori (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | A/R | Y | 90 | Power Operation | 0 | Hot Shutdown |
AUTOMATIC REACTOR SCRAM
The following information was provided by the licensee via phone and email:
"At 0329 [CDT] on August 11, 2023, with Unit 2 in Mode 1 at 90 percent power, the reactor automatically tripped due to a turbine trip. The trip was uncomplicated with all systems responding normally post-trip. The cause and details of the event are under investigation. Containment isolation valves actuated closed in multiple systems on a valid Group II signal.
"Due to the 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), and an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) for the Group II isolation.
"Operations responded using the emergency operating procedure and stabilized the plant in Mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 is not affected.
"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:
"At 0329 [CDT] on August 11, 2023, with Unit 2 in Mode 1 at 90 percent power, the reactor automatically tripped due to a turbine trip. The trip was uncomplicated with all systems responding normally post-trip. The cause and details of the event are under investigation. Containment isolation valves actuated closed in multiple systems on a valid Group II signal.
"Due to the 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), and an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) for the Group II isolation.
"Operations responded using the emergency operating procedure and stabilized the plant in Mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 is not affected.
"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."