Event Notification Report for July 17, 2005
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
07/16/2005 - 07/17/2005
EVENT NUMBERS
41847
Power Reactor
Event Number: 41847
Facility: FERMI
Region: 3 State: MI
Unit: [2] [] []
RX Type: [2] GE-4
NRC Notified By: DEREK DROCKELMAN
HQ OPS Officer: PETE SNYDER
Region: 3 State: MI
Unit: [2] [] []
RX Type: [2] GE-4
NRC Notified By: DEREK DROCKELMAN
HQ OPS Officer: PETE SNYDER
Notification Date: 07/18/2005
Notification Time: 00:18 [ET]
Event Date: 07/17/2005
Event Time: 22:31 [EDT]
Last Update Date: 07/18/2005
Notification Time: 00:18 [ET]
Event Date: 07/17/2005
Event Time: 22:31 [EDT]
Last Update Date: 07/18/2005
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
Person (Organization):
PATTY PELKE (R3)
PATTY PELKE (R3)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 74 | Power Operation | 74 | Power Operation |
UNANALYZED CONDITION OF MAINTENANCE BUS TIE BREAKERS
"During review of 10CFR50 Appendix R, III.G.2 compliance, it was discovered that a fire in a divisional switchgear room affecting maintenance tie breakers 64T or 65T, may result in the opposite division diesels [tripping]. The postulated fire could affect cables associated with a maintenance tie breaker which could in turn cause associated bus tie breakers in the opposite division to close (B9, C9, E9, F9). The III.G.2 scenario would also include a Loss of Offsite Power event which would require the [Emergency Diesel Generators] (EDG's) to be running. Postulating multiple hot shorts could result in both 9 breakers in a single division closing and paralleling the EDG's out of synch resulting in potential damage to the EDG's.
"Compensatory action: Eliminated this failure mechanism by racking out the four tie breakers (B9, C9, E9, F9) that could be affected. This does not affect operability of the EDG's."
The licensee notified the NRC Resident Inspector.
"During review of 10CFR50 Appendix R, III.G.2 compliance, it was discovered that a fire in a divisional switchgear room affecting maintenance tie breakers 64T or 65T, may result in the opposite division diesels [tripping]. The postulated fire could affect cables associated with a maintenance tie breaker which could in turn cause associated bus tie breakers in the opposite division to close (B9, C9, E9, F9). The III.G.2 scenario would also include a Loss of Offsite Power event which would require the [Emergency Diesel Generators] (EDG's) to be running. Postulating multiple hot shorts could result in both 9 breakers in a single division closing and paralleling the EDG's out of synch resulting in potential damage to the EDG's.
"Compensatory action: Eliminated this failure mechanism by racking out the four tie breakers (B9, C9, E9, F9) that could be affected. This does not affect operability of the EDG's."
The licensee notified the NRC Resident Inspector.