Event Notification Report for April 09, 2000
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
04/08/2000 - 04/09/2000
EVENT NUMBERS
36878
Power Reactor
Event Number: 36878
Facility: FARLEY
Region: 2 State: AL
Unit: [1] [] []
RX Type: [1] W-3-LP,[2] W-3-LP
NRC Notified By: BILL ARENS
HQ OPS Officer: JOHN MacKINNON
Region: 2 State: AL
Unit: [1] [] []
RX Type: [1] W-3-LP,[2] W-3-LP
NRC Notified By: BILL ARENS
HQ OPS Officer: JOHN MacKINNON
Notification Date: 04/09/2000
Notification Time: 12:32 [ET]
Event Date: 04/09/2000
Event Time: 10:00 [CDT]
Last Update Date: 04/10/2000
Notification Time: 12:32 [ET]
Event Date: 04/09/2000
Event Time: 10:00 [CDT]
Last Update Date: 04/10/2000
Emergency Class: UNUSUAL EVENT
10 CFR Section:
50.72(a)(1)(i) - EMERGENCY DECLARED 50.72(b)(2)(ii) - ESF ACTUATION
10 CFR Section:
50.72(a)(1)(i) - EMERGENCY DECLARED 50.72(b)(2)(ii) - ESF ACTUATION
Person (Organization):
STEVE CAHILL (R2)
STEVE CAHILL (R2)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Refueling | 0 | Refueling |
LOSS OF BOTH VITAL BUSES DURING 'B' TRAIN LOAD SHED TESTING
At 1000 CDT, during Unit 1 'B' train load shed testing (performed every 18 months during a refueling outage), the 'A' startup transformer tripped, resulting in a loss of offsite power to both trains of Unit 1 vital buses, the autostart of 'A' train emergency diesel generators (EDGs) which reenergized the 'A' train buses, and the sustained deenergization of the 'B' train vital buses.
At the time of this event, Unit 1 was defueled, with the 'B' train service water system out of service and the 'B' train EDG unavailable to Unit 1. Both trains of Unit 1 vital power were aligned to the '1A' startup transformer as part of the load shed test that was in progress. The loss of the '1A' startup transformer coincided with, and appears to be associated with, the removal of a jumper from a 'B' train sequencer relay. Investigation of this apparent cause is continuing.
The 'A' train vital buses were immediately restored to service by the 'A' train EDGs.
At 1018 CDT, spent fuel pool cooling was manually restored. Spent fuel pool temperature remained at 98°F throughout this event.
At 1019 CDT. the 'B' train buses were manually reenergized from the '1B' startup transformer.
At 1053 CDT, the 'A' train buses were transferred from the EDGs to offsite power.
Unit 2 remains at 100% power and is unaffected by this event.
The NRC Resident Inspector was notified of this event by the licensee.
* * * UPDATE AT 1615 ON 4/10/00, BY COLLINS RECEIVED BY WEAVER * * *
The following is an update to the above non-emergency report:
The purpose of this emergency notification is to retroactively declare and terminate a Notice of Unusual Event (NOUE) that occurred on April 9, 2000. As of 1000 CDT on April 9, 2000, a NOUE was declared due to a loss of offsite power to the Unit 1 vital buses. The emergency declaration was terminated at 1019 CDT on April 9, 2000 at which time one train of vital power was reestablished from offsite power supply. During this event, one train of vital power was automatically supplied from an EDG.
At the time of the event, Unit 1 was defueled. The 'B' train EDG was not available due to routine outage activities and the Unit 1 'A' startup transformer was supplying both trains of vital buses from offsite power.
At 1000 CDT on April 9, 2000, the Unit 1 'A' startup transformer tripped for unknown reason, resulting in a loss of power to both trains of vital electrical buses. Both 'A' train EDGs automatically started and reenergized the Unit 1 'A' train vital buses within seconds. The Unit 1 'B' train vital buses remained deenergized for about 19 minutes until the Unit 1 'B' startup transformer was aligned by the operators to supply power to them. The cause of the Unit 1 ' A' startup transformer trip is unknown and being investigated.
This event resulted in a brief loss of spent fuel pool cooling. Spent fuel pool cooling was restored by the operators at 1018 CDT on April 9, 2000 in accordance with plant procedures. The temperature of the spent fuel pool remained constant at 98°F throughout this event. Following a walkdown for faults, the Unit 1 'B' train vital buses were reenergized from offsite power at 1019 CDT from the Unit 1 'B' startup transformer. Offsite electrical power was restored to the 'A' train vital buses at 1053 CDT and the EDGs were secured and returned to normal standby alignment. The operations shift crew evaluated this event and reported it to the NRC as a four hour non-emergency report per 10CFR50.72. The operations shift crew recognized the momentary loss of power to the vital buses but after reviewing the emergency implementation procedures and Technical Specifications concluded that a loss of both trains of offsite power had not occurred. That was concluded since the operators were readily able to align the Unit 1 'B' startup transformer to supply the 'B' train vital buses. Further evaluation of the event on April 10, 2000, concluded that a NOUE was appropriate since offsite power was momentarily lost to the vital electrical buses.
Unit 2 remained at 100% power during this event and was unaffected by this event.
The licensee informed the NRC resident inspector of this notification.
The NRC Operations Officer notified the R2DO (Cahill), NRR EO (Marsh), IRO (Giitter) and FEMA (Steindruff).
At 1000 CDT, during Unit 1 'B' train load shed testing (performed every 18 months during a refueling outage), the 'A' startup transformer tripped, resulting in a loss of offsite power to both trains of Unit 1 vital buses, the autostart of 'A' train emergency diesel generators (EDGs) which reenergized the 'A' train buses, and the sustained deenergization of the 'B' train vital buses.
At the time of this event, Unit 1 was defueled, with the 'B' train service water system out of service and the 'B' train EDG unavailable to Unit 1. Both trains of Unit 1 vital power were aligned to the '1A' startup transformer as part of the load shed test that was in progress. The loss of the '1A' startup transformer coincided with, and appears to be associated with, the removal of a jumper from a 'B' train sequencer relay. Investigation of this apparent cause is continuing.
The 'A' train vital buses were immediately restored to service by the 'A' train EDGs.
At 1018 CDT, spent fuel pool cooling was manually restored. Spent fuel pool temperature remained at 98°F throughout this event.
At 1019 CDT. the 'B' train buses were manually reenergized from the '1B' startup transformer.
At 1053 CDT, the 'A' train buses were transferred from the EDGs to offsite power.
Unit 2 remains at 100% power and is unaffected by this event.
The NRC Resident Inspector was notified of this event by the licensee.
* * * UPDATE AT 1615 ON 4/10/00, BY COLLINS RECEIVED BY WEAVER * * *
The following is an update to the above non-emergency report:
The purpose of this emergency notification is to retroactively declare and terminate a Notice of Unusual Event (NOUE) that occurred on April 9, 2000. As of 1000 CDT on April 9, 2000, a NOUE was declared due to a loss of offsite power to the Unit 1 vital buses. The emergency declaration was terminated at 1019 CDT on April 9, 2000 at which time one train of vital power was reestablished from offsite power supply. During this event, one train of vital power was automatically supplied from an EDG.
At the time of the event, Unit 1 was defueled. The 'B' train EDG was not available due to routine outage activities and the Unit 1 'A' startup transformer was supplying both trains of vital buses from offsite power.
At 1000 CDT on April 9, 2000, the Unit 1 'A' startup transformer tripped for unknown reason, resulting in a loss of power to both trains of vital electrical buses. Both 'A' train EDGs automatically started and reenergized the Unit 1 'A' train vital buses within seconds. The Unit 1 'B' train vital buses remained deenergized for about 19 minutes until the Unit 1 'B' startup transformer was aligned by the operators to supply power to them. The cause of the Unit 1 ' A' startup transformer trip is unknown and being investigated.
This event resulted in a brief loss of spent fuel pool cooling. Spent fuel pool cooling was restored by the operators at 1018 CDT on April 9, 2000 in accordance with plant procedures. The temperature of the spent fuel pool remained constant at 98°F throughout this event. Following a walkdown for faults, the Unit 1 'B' train vital buses were reenergized from offsite power at 1019 CDT from the Unit 1 'B' startup transformer. Offsite electrical power was restored to the 'A' train vital buses at 1053 CDT and the EDGs were secured and returned to normal standby alignment. The operations shift crew evaluated this event and reported it to the NRC as a four hour non-emergency report per 10CFR50.72. The operations shift crew recognized the momentary loss of power to the vital buses but after reviewing the emergency implementation procedures and Technical Specifications concluded that a loss of both trains of offsite power had not occurred. That was concluded since the operators were readily able to align the Unit 1 'B' startup transformer to supply the 'B' train vital buses. Further evaluation of the event on April 10, 2000, concluded that a NOUE was appropriate since offsite power was momentarily lost to the vital electrical buses.
Unit 2 remained at 100% power during this event and was unaffected by this event.
The licensee informed the NRC resident inspector of this notification.
The NRC Operations Officer notified the R2DO (Cahill), NRR EO (Marsh), IRO (Giitter) and FEMA (Steindruff).