Event Notification Report for February 24, 2024
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
02/23/2024 - 02/24/2024
Power Reactor
Event Number: 56990
Facility: Browns Ferry
Region: 2 State: AL
Unit: [3] [] []
RX Type: [1] GE-4,[2] GE-4,[3] GE-4
NRC Notified By: Chase Hensley
HQ OPS Officer: Sam Colvard
Region: 2 State: AL
Unit: [3] [] []
RX Type: [1] GE-4,[2] GE-4,[3] GE-4
NRC Notified By: Chase Hensley
HQ OPS Officer: Sam Colvard
Notification Date: 02/24/2024
Notification Time: 09:27 [ET]
Event Date: 02/24/2024
Event Time: 02:19 [CST]
Last Update Date: 02/24/2024
Notification Time: 09:27 [ET]
Event Date: 02/24/2024
Event Time: 02:19 [CST]
Last Update Date: 02/24/2024
Emergency Class: Non Emergency
10 CFR Section:
50.72(b)(3)(iv)(A) - Valid Specif Sys Actuation
10 CFR Section:
50.72(b)(3)(iv)(A) - Valid Specif Sys Actuation
Person (Organization):
Miller, Mark (R2DO)
Miller, Mark (R2DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 3 | N | N | 0 | Refueling | 0 | Refueling |
AUTOMATIC START OF EMERGENCY DIESEL GENERATOR
The following information was provided by the licensee via phone and email:
"At 0219 CST on February 24, 2024, Browns Ferry Unit 3 was shut down in a refueling outage, while closing 4 kV shutdown board breaker 3EB-9, the 4 kV shutdown board normal feeder breaker tripped open resulting in a valid 4 kV bus under-voltage condition. Due to the under-voltage condition, the 3B emergency diesel generator (EDG) auto started and tied to the board. The cause of the breaker tripping open is unknown and an investigation is in progress.
"All systems responded as expected for the loss of voltage. This event requires an 8-hour report per 10 CFR 50.72(b)(3)(iv)(A). 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:
No other safety related equipment was affected. The 3B EDG continues to supply the shutdown board pending further investigation.
The following information was provided by the licensee via phone and email:
"At 0219 CST on February 24, 2024, Browns Ferry Unit 3 was shut down in a refueling outage, while closing 4 kV shutdown board breaker 3EB-9, the 4 kV shutdown board normal feeder breaker tripped open resulting in a valid 4 kV bus under-voltage condition. Due to the under-voltage condition, the 3B emergency diesel generator (EDG) auto started and tied to the board. The cause of the breaker tripping open is unknown and an investigation is in progress.
"All systems responded as expected for the loss of voltage. This event requires an 8-hour report per 10 CFR 50.72(b)(3)(iv)(A). 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:
No other safety related equipment was affected. The 3B EDG continues to supply the shutdown board pending further investigation.
Power Reactor
Event Number: 56991
Facility: Calvert Cliffs
Region: 1 State: MD
Unit: [2] [] []
RX Type: [1] CE,[2] CE
NRC Notified By: Calvin Holston
HQ OPS Officer: Kerby Scales
Region: 1 State: MD
Unit: [2] [] []
RX Type: [1] CE,[2] CE
NRC Notified By: Calvin Holston
HQ OPS Officer: Kerby Scales
Notification Date: 02/24/2024
Notification Time: 18:08 [ET]
Event Date: 02/24/2024
Event Time: 15:46 [EST]
Last Update Date: 02/24/2024
Notification Time: 18:08 [ET]
Event Date: 02/24/2024
Event Time: 15:46 [EST]
Last Update Date: 02/24/2024
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):
Deboer, Joseph (R1DO)
Deboer, Joseph (R1DO)
| 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 DUE TO STEAM GENERATOR 22 FEED PUMP TRIP
The following information was provided by the licensee via email:
"At 1546 EST, with unit 2 at 100 percent power, the reactor was manually tripped due to the '22' steam generator feed pump tripping. The trip was uncomplicated with all systems responding normally post-trip. 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).
"Operations responded using emergency operation procedure EOP-0, Post Trip Immediate Actions and EOP-1, Uncomplicated Reactor Trip and stabilized the plant in mode 3. Decay heat is removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 is not affected.
"ESFAS [engineered safety features actuation systems] actuation (auxiliary feedwater manual actuation) is reportable under 10 CFR 50.72(b)(3)(iv)(A) 8-hour report. 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 email:
"At 1546 EST, with unit 2 at 100 percent power, the reactor was manually tripped due to the '22' steam generator feed pump tripping. The trip was uncomplicated with all systems responding normally post-trip. 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).
"Operations responded using emergency operation procedure EOP-0, Post Trip Immediate Actions and EOP-1, Uncomplicated Reactor Trip and stabilized the plant in mode 3. Decay heat is removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 is not affected.
"ESFAS [engineered safety features actuation systems] actuation (auxiliary feedwater manual actuation) is reportable under 10 CFR 50.72(b)(3)(iv)(A) 8-hour report. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."