Event Notification Report for December 10, 2006
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
12/09/2006 - 12/10/2006
EVENT NUMBERS
43042
Power Reactor
Event Number: 43042
Facility: DIABLO CANYON
Region: 4 State: CA
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: STEVE HACKLEMAN
HQ OPS Officer: BILL HUFFMAN
Region: 4 State: CA
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: STEVE HACKLEMAN
HQ OPS Officer: BILL HUFFMAN
Notification Date: 12/11/2006
Notification Time: 00:31 [ET]
Event Date: 12/10/2006
Event Time: 16:08 [PST]
Last Update Date: 12/14/2006
Notification Time: 00:31 [ET]
Event Date: 12/10/2006
Event Time: 16:08 [PST]
Last Update Date: 12/14/2006
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):
LINDA SMITH (R4)
LINDA SMITH (R4)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | M/R | N | 0 | Hot Standby | 0 | Hot Standby |
RAPID SHUTDOWN AND MANUAL REACTOR TRIP DUE TO HIGH REACTOR COOLANT PUMP STATOR TEMPERATURE
"On December 10, 2006, at 1608 PST, operators manually tripped the reactor while it was subcritical. This is an 8 hour notification per 10 CFR 50.72(b)(3)(iv)(A) for actuation of the reactor protection system while subcritical. On December 10, 2006, with Unit 2 operating in Mode 1 at 100% power, operators initiated an unplanned reactor shutdown due to indications of increasing stator temperature on reactor coolant pump 2-2. In accordance with plant procedures, when the reactor coolant pump stator temperature reached 300 degrees Fahrenheit, operators manually tripped the reactor and tripped the coolant pump 2-2. The reactor was subcritical at the time of the reactor trip but all rods had not been fully inserted.
"All control rods fully inserted in response to the reactor trip and all systems functioned as required. The auxiliary feedwater system was already in service as part of the shutdown. The grid is stable and with the exception of RCP 2-2, all major equipment including the 3 emergency diesel generators remain operable. Unit 2 electrical loads are being supplied by the normal startup power. The other 3 RCPs are maintaining forced circulation of the reactor coolant system. Investigations into the high RCP stator temperature are ongoing, the unit will remain in Mode 3 pending the results of these investigations. An estimated restart date is not known at this time. The NRC Resident Inspector has been informed and was onsite at the time of the trip. Unit 1 is unaffected and remains in Mode 1."
The licensee stated that a press release related to this event is likely.
* * * UPDATE TO HUFFMAN DURING PLANT STATUS ON 12/11/06 AT 0419 EST * * *
Licensee believes the cause of the high RCP stator temperature was due to a failed RTD.
* * * UPDATE FROM L. PARKER TO P. SNYDER AT 1531 ON 12/14/06 * * *
"Unit 2 was in Mode 3 (Hot Standby) at 0 percent power at the time of the manual trip. At the time of the Initial notification, all procedural requirements for declaring Mode 3 had not been met, but upon further review, PG&E has verified K effective was less than 0.99."
The licensee notified the NRC Resident Inspector. Notified R4DO (Proulx).
The original report was modified by this change. The 'RX Crit' field was changed from 'Y' to 'N'. The 'Init Power' field was changed from '5' to '0'. The 'Curr Power' field was changed from 'Startup' to 'Hot Standby'.
"On December 10, 2006, at 1608 PST, operators manually tripped the reactor while it was subcritical. This is an 8 hour notification per 10 CFR 50.72(b)(3)(iv)(A) for actuation of the reactor protection system while subcritical. On December 10, 2006, with Unit 2 operating in Mode 1 at 100% power, operators initiated an unplanned reactor shutdown due to indications of increasing stator temperature on reactor coolant pump 2-2. In accordance with plant procedures, when the reactor coolant pump stator temperature reached 300 degrees Fahrenheit, operators manually tripped the reactor and tripped the coolant pump 2-2. The reactor was subcritical at the time of the reactor trip but all rods had not been fully inserted.
"All control rods fully inserted in response to the reactor trip and all systems functioned as required. The auxiliary feedwater system was already in service as part of the shutdown. The grid is stable and with the exception of RCP 2-2, all major equipment including the 3 emergency diesel generators remain operable. Unit 2 electrical loads are being supplied by the normal startup power. The other 3 RCPs are maintaining forced circulation of the reactor coolant system. Investigations into the high RCP stator temperature are ongoing, the unit will remain in Mode 3 pending the results of these investigations. An estimated restart date is not known at this time. The NRC Resident Inspector has been informed and was onsite at the time of the trip. Unit 1 is unaffected and remains in Mode 1."
The licensee stated that a press release related to this event is likely.
* * * UPDATE TO HUFFMAN DURING PLANT STATUS ON 12/11/06 AT 0419 EST * * *
Licensee believes the cause of the high RCP stator temperature was due to a failed RTD.
* * * UPDATE FROM L. PARKER TO P. SNYDER AT 1531 ON 12/14/06 * * *
"Unit 2 was in Mode 3 (Hot Standby) at 0 percent power at the time of the manual trip. At the time of the Initial notification, all procedural requirements for declaring Mode 3 had not been met, but upon further review, PG&E has verified K effective was less than 0.99."
The licensee notified the NRC Resident Inspector. Notified R4DO (Proulx).
The original report was modified by this change. The 'RX Crit' field was changed from 'Y' to 'N'. The 'Init Power' field was changed from '5' to '0'. The 'Curr Power' field was changed from 'Startup' to 'Hot Standby'.