Event Notification Report for July 26, 2003
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
07/25/2003 - 07/26/2003
EVENT NUMBERS
40023
Power Reactor
Event Number: 40023
Facility: PRAIRIE ISLAND
Region: 3 State: MN
Unit: [] [2] []
RX Type: [1] W-2-LP,[2] W-2-LP
NRC Notified By: STEVE SEILHYMER
HQ OPS Officer: ARLON COSTA
Region: 3 State: MN
Unit: [] [2] []
RX Type: [1] W-2-LP,[2] W-2-LP
NRC Notified By: STEVE SEILHYMER
HQ OPS Officer: ARLON COSTA
Notification Date: 07/27/2003
Notification Time: 02:14 [ET]
Event Date: 07/26/2003
Event Time: 21:39 [CDT]
Last Update Date: 07/27/2003
Notification Time: 02:14 [ET]
Event Date: 07/26/2003
Event Time: 21:39 [CDT]
Last Update Date: 07/27/2003
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):
ANNE MARIE STONE (R3)
ANNE MARIE STONE (R3)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
LOSS OF POWER TO 4160 V BUS DUE TO A GROUND FAULT
"A ground fault on the tertiary winding of 10 TR Substation Transformer resulted in a loss of power to Unit 2 Safeguard 4160 V Bus 26. Bus 26 Load Sequencer automatically initiated voltage restoration to re-power the bus from 2RY Station Reserve Transformer. Load Sequencer operation also generated automatic load rejection and load restoration of Bus 26 loads."
All safeguards loads on Bus 26 that would have been rejected by the sequencer were not running. Containment fan cooling units were restored. Manually restored reactor coolant pump seal injection. Tertiary Cooling Systems that provide flow to the cooling towers are still off. All other systems functioned as required.
The licensee will notify the NRC Resident Inspector.
"A ground fault on the tertiary winding of 10 TR Substation Transformer resulted in a loss of power to Unit 2 Safeguard 4160 V Bus 26. Bus 26 Load Sequencer automatically initiated voltage restoration to re-power the bus from 2RY Station Reserve Transformer. Load Sequencer operation also generated automatic load rejection and load restoration of Bus 26 loads."
All safeguards loads on Bus 26 that would have been rejected by the sequencer were not running. Containment fan cooling units were restored. Manually restored reactor coolant pump seal injection. Tertiary Cooling Systems that provide flow to the cooling towers are still off. All other systems functioned as required.
The licensee will notify the NRC Resident Inspector.