Event Notification Report for August 04, 2001
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
08/03/2001 - 08/04/2001
Power Reactor
Event Number: 38186
Facility: DIABLO CANYON
Region: 4 State: CA
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DAVID BAHNER
HQ OPS Officer: STEVE SANDIN
Region: 4 State: CA
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DAVID BAHNER
HQ OPS Officer: STEVE SANDIN
Notification Date: 08/04/2001
Notification Time: 19:55 [ET]
Event Date: 08/04/2001
Event Time: 15:22 [PDT]
Last Update Date: 08/09/2001
Notification Time: 19:55 [ET]
Event Date: 08/04/2001
Event Time: 15:22 [PDT]
Last Update Date: 08/09/2001
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):
CHUCK CAIN (R4)
HERB BERKOW (NRR)
CHUCK CAIN (R4)
HERB BERKOW (NRR)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 100 | Power Operation |
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
AUTOMATIC START OF BOTH UNITS DIESEL GENERATORS DUE TO A LOSS OF START-UP POWER
"Electrical fault caused loss of Start-up Power to both units. This caused all six [6] diesel generators on both units to automatically start."
Circuit breaker CB212 which supplies 230KV start-up power to both units opened due to an unidentified electrical fault. Initial indication was a loss of power to outbuildings onsite followed about twenty-two (22) minutes later with a loss of power to the Start-up transformers. Investigation found the grounding fuses on the Unit 1 side open. Should a unit trip occur while in this condition, RCS cooldown by natural circulation would be required.
Both units are in Tech Spec LCO 3.8.1 Condition 'A' which requires restoration of start-up power within 72-hours or unit shutdown; mode 3 (hot standby) in the following 6-hours followed by mode 5 (cold shutdown) 36-hours later. The licensee is performing a maintenance and engineering evaluation to determine if start-up can be restored by closing a cross-tie breaker from Unit 2.
None of the diesel generators loaded and all have been secured and returned to standby.
The licensee informed the NRC resident inspector.
***** UPDATE FROM JEFF KNISLEY TO LEIGH TROCINE RECEIVED AT 1759 EDT ON 08/09/01 *****
The following text is a portion of a facsimile received from the licensee:
"[...] FOLLOW-UP INFORMATION"
"The event, as described in the original event notification number 38186, caused all six diesel generators on both units to automatically start. The diesel generators started, as designed, upon receiving an anticipatory signal due to the loss of Start-Up Power; and the diesel generators did not load, as designed, because vital and non vital power was still available from the Auxiliary Transformers, back-fed from the generator output of each unit."
"As stated in the original event notification, the grounding fuses for the Unit 1 Start-Up Transformer were found open. The immediate cause of the event was a fault in the 12kV Fuse Cabinet for the Unit 1 Start-Up Transformer ground resistor. The ground resistor was observed to be radiating heat just prior to the event witnessed by the damage to the Fuse Cabinet. The cause of this failure is being investigated within the corrective action program."
"As stated in the original event notification, there was a loss of power to outbuildings onsite. The 12kV underground distribution breaker tripped [on 08/04/01 at] 1500 PDT, causing the loss of non-essential site loads; such as the Administration, Training and Maintenance Buildings, and support facilities -supporting power production including water treatment for Condensate make-up, back-up Service Air Compressors, and Radwaste Laundry Building."
"Start-Up power to Unit 2 was restored [on 08/05/01 at] 0513 PDT. After assuring there was no damage to the Unit 1 Start-Up Bus, power was restored to the Unit 1 Start-Up Bus [on 08/06/01 at] 1122 PDT, via a cross-tie breaker from the Unit 2 Start-Up Transformer. The 12kV underground loop was reenergized [on 08/07/01], thus restoring power to the non-essential site loads. Repair of the Fuse Cabinet is in progress."
The licensee notified the NRC resident inspector. The NRC operations officer notified the R4DO (Charles Marschall).
"Electrical fault caused loss of Start-up Power to both units. This caused all six [6] diesel generators on both units to automatically start."
Circuit breaker CB212 which supplies 230KV start-up power to both units opened due to an unidentified electrical fault. Initial indication was a loss of power to outbuildings onsite followed about twenty-two (22) minutes later with a loss of power to the Start-up transformers. Investigation found the grounding fuses on the Unit 1 side open. Should a unit trip occur while in this condition, RCS cooldown by natural circulation would be required.
Both units are in Tech Spec LCO 3.8.1 Condition 'A' which requires restoration of start-up power within 72-hours or unit shutdown; mode 3 (hot standby) in the following 6-hours followed by mode 5 (cold shutdown) 36-hours later. The licensee is performing a maintenance and engineering evaluation to determine if start-up can be restored by closing a cross-tie breaker from Unit 2.
None of the diesel generators loaded and all have been secured and returned to standby.
The licensee informed the NRC resident inspector.
***** UPDATE FROM JEFF KNISLEY TO LEIGH TROCINE RECEIVED AT 1759 EDT ON 08/09/01 *****
The following text is a portion of a facsimile received from the licensee:
"[...] FOLLOW-UP INFORMATION"
"The event, as described in the original event notification number 38186, caused all six diesel generators on both units to automatically start. The diesel generators started, as designed, upon receiving an anticipatory signal due to the loss of Start-Up Power; and the diesel generators did not load, as designed, because vital and non vital power was still available from the Auxiliary Transformers, back-fed from the generator output of each unit."
"As stated in the original event notification, the grounding fuses for the Unit 1 Start-Up Transformer were found open. The immediate cause of the event was a fault in the 12kV Fuse Cabinet for the Unit 1 Start-Up Transformer ground resistor. The ground resistor was observed to be radiating heat just prior to the event witnessed by the damage to the Fuse Cabinet. The cause of this failure is being investigated within the corrective action program."
"As stated in the original event notification, there was a loss of power to outbuildings onsite. The 12kV underground distribution breaker tripped [on 08/04/01 at] 1500 PDT, causing the loss of non-essential site loads; such as the Administration, Training and Maintenance Buildings, and support facilities -supporting power production including water treatment for Condensate make-up, back-up Service Air Compressors, and Radwaste Laundry Building."
"Start-Up power to Unit 2 was restored [on 08/05/01 at] 0513 PDT. After assuring there was no damage to the Unit 1 Start-Up Bus, power was restored to the Unit 1 Start-Up Bus [on 08/06/01 at] 1122 PDT, via a cross-tie breaker from the Unit 2 Start-Up Transformer. The 12kV underground loop was reenergized [on 08/07/01], thus restoring power to the non-essential site loads. Repair of the Fuse Cabinet is in progress."
The licensee notified the NRC resident inspector. The NRC operations officer notified the R4DO (Charles Marschall).
Power Reactor
Event Number: 38241
Facility: PEACH BOTTOM
Region: 1 State: PA
Unit: [2] [] []
RX Type: [2] GE-4,[3] GE-4
NRC Notified By: BILL CAMPBELL
HQ OPS Officer: FANGIE JONES
Region: 1 State: PA
Unit: [2] [] []
RX Type: [2] GE-4,[3] GE-4
NRC Notified By: BILL CAMPBELL
HQ OPS Officer: FANGIE JONES
Notification Date: 08/28/2001
Notification Time: 13:14 [ET]
Event Date: 08/04/2001
Event Time: 23:47 [EDT]
Last Update Date: 08/28/2001
Notification Time: 13:14 [ET]
Event Date: 08/04/2001
Event Time: 23:47 [EDT]
Last Update Date: 08/28/2001
Emergency Class: NON EMERGENCY
10 CFR Section:
50.73(a)(1) - INVALID SPECIF SYSTEM ACTUATION
10 CFR Section:
50.73(a)(1) - INVALID SPECIF SYSTEM ACTUATION
Person (Organization):
DAVID LEW (R1)
DAVID LEW (R1)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 42 | Power Operation | 42 | Power Operation |
60 DAY REPORT - PCIV OUTBOARD ISOLATION VALVE CLOSURE
"This 60-day optional report, as allowed by 10 CFR 50.73(a)(1), is being made under the reporting requirement in 10CFR50.73(a)(2)(iv)(A) to describe an unplanned, invalid actuation of a specified system, specifically Primary
Containment Isolation Valve (PCIV) Group 2 outboard valves.
"On August 04, 2001, a spurious audio tone transfer trip caused a loss of an offsite electrical source which resulted in 4KV emergency buses automatically transferring to their respective alternate power supply. During the power transfer, the PCIV Group 2 outboard valves isolated due to a momentary loss of power to the valve logic.
"The PCIVs isolated as expected for the given conditions and the valves were subsequently reopened when power was restored. No deficiencies or abnormalities were noted during valve operation.
"This event has been entered into the site-specific corrective action program for resolution.
"The resident has been informed."
"This 60-day optional report, as allowed by 10 CFR 50.73(a)(1), is being made under the reporting requirement in 10CFR50.73(a)(2)(iv)(A) to describe an unplanned, invalid actuation of a specified system, specifically Primary
Containment Isolation Valve (PCIV) Group 2 outboard valves.
"On August 04, 2001, a spurious audio tone transfer trip caused a loss of an offsite electrical source which resulted in 4KV emergency buses automatically transferring to their respective alternate power supply. During the power transfer, the PCIV Group 2 outboard valves isolated due to a momentary loss of power to the valve logic.
"The PCIVs isolated as expected for the given conditions and the valves were subsequently reopened when power was restored. No deficiencies or abnormalities were noted during valve operation.
"This event has been entered into the site-specific corrective action program for resolution.
"The resident has been informed."