Event Notification Report for March 23, 2024
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
03/22/2024 - 03/23/2024
EVENT NUMBERS
57046
57046
Power Reactor
Event Number: 57046
Facility: Fermi
Region: 3 State: MI
Unit: [2] [] []
RX Type: [2] GE-4
NRC Notified By: Trevor Jarrait
HQ OPS Officer: Adam Koziol
Region: 3 State: MI
Unit: [2] [] []
RX Type: [2] GE-4
NRC Notified By: Trevor Jarrait
HQ OPS Officer: Adam Koziol
Notification Date: 03/23/2024
Notification Time: 03:47 [ET]
Event Date: 03/23/2024
Event Time: 00:04 [EDT]
Last Update Date: 04/22/2024
Notification Time: 03:47 [ET]
Event Date: 03/23/2024
Event Time: 00:04 [EDT]
Last Update Date: 04/22/2024
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 50.72(b)(3)(v)(D) - Accident Mitigation
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS Actuation - Critical 50.72(b)(3)(iv)(A) - Valid Specif Sys Actuation 50.72(b)(3)(v)(D) - Accident Mitigation
Person (Organization):
Hills, David (R3DO)
Hills, David (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | A/R | Y | 23 | Power Operation | 0 | Hot Shutdown |
EN Revision Imported Date: 4/23/2024
EN Revision Text: AUTOMATIC REACTOR TRIP
The following information was provided by the licensee via email:
"At 0004 EDT on March 23, 2024, with the unit in Mode 1 at 23 percent power, the reactor automatically scrammed due to high reactor pressure vessel pressure when the turbine bypass valves unexpectedly closed while attempting to lower generator MW to 55 MWe to support shutdown for a refueling outage. The scram was not complex, with systems responding normally post-scram, with the exception of the pressure control system. The transient occurred while lowering on turbine speed/load demand which caused a rise in pressure and power until the reactor protection system setpoint for reactor pressure high was exceeded and resulted in an automatic reactor scram. The plant was preparing to shut down for a refueling outage when the trip occurred.
"Operations responded and stabilized the plant. Reactor water level is being maintained at normal level. Decay heat is being removed by the main steam system to the main condenser using manual operation of the turbine bypass valves. All control rods inserted into the core.
"Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CPR 50.72(b)(2)(iv)(B). Additionally, received expected [primary containment] isolations for Level 3: Group 13 drywell sumps, Group 15 [traverse in-core probe] TlPs (which was already isolated) and Group 4 [residual heat removal - shutdown cooling] RHR-SDC (which was already isolated). The primary containment isolation event is being reported under 10 CFR 50.72(b)(3)(iv)(A). Also, due to the main turbine bypass valves unexpectedly closing, this is also being reported under 10 CFR 50.72(b)(3)(v)(D).
"There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
* * * UPDATE ON 4/22/24 AT 1448 EDT FROM WHITNEY HEMINGWAY TO ADAM KOZIOL * * *
"The purpose of this notification is to retract the 10 CFR 50.72(b)(3)(v)(D) reporting criteria of event notification 57046 reported on March 23,2024. Based on further evaluation, Fermi 2 has concluded that there was no event or condition that could have prevented fulfillment of a safety function that was needed to mitigate the consequence of an accident. Although discussed in Chapter 15 of the UFSAR, the turbine bypass valves do not provide a safety related function and are not credited safety related components for accident mitigation. Therefore, Fermi 2 is retracting the 10 CFR 50.72(b)(3)(v)(D) reporting criteria that was included on the March 23, 2024 event notification."
Notified R3DO (Betancourt-Roldan)
EN Revision Text: AUTOMATIC REACTOR TRIP
The following information was provided by the licensee via email:
"At 0004 EDT on March 23, 2024, with the unit in Mode 1 at 23 percent power, the reactor automatically scrammed due to high reactor pressure vessel pressure when the turbine bypass valves unexpectedly closed while attempting to lower generator MW to 55 MWe to support shutdown for a refueling outage. The scram was not complex, with systems responding normally post-scram, with the exception of the pressure control system. The transient occurred while lowering on turbine speed/load demand which caused a rise in pressure and power until the reactor protection system setpoint for reactor pressure high was exceeded and resulted in an automatic reactor scram. The plant was preparing to shut down for a refueling outage when the trip occurred.
"Operations responded and stabilized the plant. Reactor water level is being maintained at normal level. Decay heat is being removed by the main steam system to the main condenser using manual operation of the turbine bypass valves. All control rods inserted into the core.
"Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CPR 50.72(b)(2)(iv)(B). Additionally, received expected [primary containment] isolations for Level 3: Group 13 drywell sumps, Group 15 [traverse in-core probe] TlPs (which was already isolated) and Group 4 [residual heat removal - shutdown cooling] RHR-SDC (which was already isolated). The primary containment isolation event is being reported under 10 CFR 50.72(b)(3)(iv)(A). Also, due to the main turbine bypass valves unexpectedly closing, this is also being reported under 10 CFR 50.72(b)(3)(v)(D).
"There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
* * * UPDATE ON 4/22/24 AT 1448 EDT FROM WHITNEY HEMINGWAY TO ADAM KOZIOL * * *
"The purpose of this notification is to retract the 10 CFR 50.72(b)(3)(v)(D) reporting criteria of event notification 57046 reported on March 23,2024. Based on further evaluation, Fermi 2 has concluded that there was no event or condition that could have prevented fulfillment of a safety function that was needed to mitigate the consequence of an accident. Although discussed in Chapter 15 of the UFSAR, the turbine bypass valves do not provide a safety related function and are not credited safety related components for accident mitigation. Therefore, Fermi 2 is retracting the 10 CFR 50.72(b)(3)(v)(D) reporting criteria that was included on the March 23, 2024 event notification."
Notified R3DO (Betancourt-Roldan)