Event Notification Report for May 12, 2007
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
05/11/2007 - 05/12/2007
EVENT NUMBERS
43360
Power Reactor
Event Number: 43360
Facility: DIABLO CANYON
Region: 4 State: CA
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: JAN NIMICK
HQ OPS Officer: JASON KOZAL
Region: 4 State: CA
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: JAN NIMICK
HQ OPS Officer: JASON KOZAL
Notification Date: 05/12/2007
Notification Time: 18:09 [ET]
Event Date: 05/12/2007
Event Time: 10:25 [PDT]
Last Update Date: 05/12/2007
Notification Time: 18:09 [ET]
Event Date: 05/12/2007
Event Time: 10:25 [PDT]
Last Update Date: 05/12/2007
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):
VINCENT GADDY (R4)
VINCENT GADDY (R4)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Refueling | 0 | Refueling |
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
EMERGENCY DIESEL GENERATORS START DUE TO LOSS OF OFF SITE START UP POWER
"On May 12, 2007, at 10:25 am PST, offsite startup power was lost to Diablo Canyon Units 1 and 2. This is the 8-hour non-emergency event notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) for a valid actuation of five emergency diesel generators (EDGs) due to the loss of startup power.
"Unit 1 is in a refueling outage in No Mode, with all fuel offloaded to the spent fuel pool (SFP). Auxiliary power is cleared for maintenance and offsite power was being provided by startup power. EDG 1-3 was also cleared for maintenance. On the loss of startup power, EDGs 1-1 and 1-2 auto-started and powered their loads. Since SFP cooling is not automatically loaded on the EDGs, Operators re-started a SFP Cooling pump. This re-established decay heat removal via component cooling water (CCW) (two of three pumps remained operable) and auxiliary saltwater pump 1-2. SFP temperature remained at approximately 105 degrees F.
"Unit 2 remained in Mode 1 at 100 percent power with auxiliary power supplying Unit 2 equipment. The loss of startup power caused all three EDGs to auto-start but they did not load.
"At approximately 11:30am PDT, startup power was restored to the site via the Mesa substation. Operators completed restoration of startup power to plant equipment by approximately 14:30 PDT.
"The cause of the loss of startup power was reported as a failed Morro Bay - Diablo transmission line."
The licensee notified the NRC Resident Inspector.
"On May 12, 2007, at 10:25 am PST, offsite startup power was lost to Diablo Canyon Units 1 and 2. This is the 8-hour non-emergency event notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) for a valid actuation of five emergency diesel generators (EDGs) due to the loss of startup power.
"Unit 1 is in a refueling outage in No Mode, with all fuel offloaded to the spent fuel pool (SFP). Auxiliary power is cleared for maintenance and offsite power was being provided by startup power. EDG 1-3 was also cleared for maintenance. On the loss of startup power, EDGs 1-1 and 1-2 auto-started and powered their loads. Since SFP cooling is not automatically loaded on the EDGs, Operators re-started a SFP Cooling pump. This re-established decay heat removal via component cooling water (CCW) (two of three pumps remained operable) and auxiliary saltwater pump 1-2. SFP temperature remained at approximately 105 degrees F.
"Unit 2 remained in Mode 1 at 100 percent power with auxiliary power supplying Unit 2 equipment. The loss of startup power caused all three EDGs to auto-start but they did not load.
"At approximately 11:30am PDT, startup power was restored to the site via the Mesa substation. Operators completed restoration of startup power to plant equipment by approximately 14:30 PDT.
"The cause of the loss of startup power was reported as a failed Morro Bay - Diablo transmission line."
The licensee notified the NRC Resident Inspector.