Event Notification Report for March 17, 2003
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
03/16/2003 - 03/17/2003
EVENT NUMBERS
39675
Power Reactor
Event Number: 39675
Facility: DIABLO CANYON
Region: 4 State: CA
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DYE
HQ OPS Officer: CHAUNCEY GOULD
Region: 4 State: CA
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DYE
HQ OPS Officer: CHAUNCEY GOULD
Notification Date: 03/17/2003
Notification Time: 16:48 [ET]
Event Date: 03/17/2003
Event Time: 08:18 [PST]
Last Update Date: 03/17/2003
Notification Time: 16:48 [ET]
Event Date: 03/17/2003
Event Time: 08:18 [PST]
Last Update Date: 03/17/2003
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):
CLAUDE JOHNSON (R4)
CLAUDE JOHNSON (R4)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | N | 0 | Hot Standby | 0 | Hot Standby |
REACTOR WAS MANUALLY TRIPPED WHILE IN MODE 3 DUE TO ONE ROD REMAINING AT 0 STEPS WHILE THE BANK OF RODS WAS BEING WITHDRAWN
"On 3/17/2003 at 0818, Unit 2 was in its 11th refueling outage in MODE 3 (hot standby). Post-maintenance testing of digital rod position indication (DRPI) was in progress in accordance with Surveillance Test Procedure (STP) R-1C. Rod control bank B was being withdrawn. As the bank of rods was withdrawn, rod F2 DRPI indication remained at 0 steps. When the bank demand position indication exceeded rod F2's DRPI indication by greater than 12 steps, the reactor trip breakers were opened by manual reactor trip initiation. This action was taken to comply with the STP precautions to positively place the control rods in a known position, i.e. fully inserted. All systems actuated as required rods fully inserted, the main turbine automatically tripped.
"Manual initiation of a reactor trip where the actuation is not part of a pre-planned evolution is reportable under 10CFR50.72. (b) (3) (iv) (A) and 50.72(b) (3) (iv) (B) (1). While the reactor trip was initiated in accordance with the STPs precautions, the manual actuation was not an expected outcome of the STP.
"Subsequently, it was determined that rod F2 was indeed on the bottom as indicated by DRPI. A moveable gripper fuse was blown preventing that rod from being withdrawn. The blown fuse was replaced and testing continued in accordance with the outage schedule."
The NRC Resident Inspector was notified.
"On 3/17/2003 at 0818, Unit 2 was in its 11th refueling outage in MODE 3 (hot standby). Post-maintenance testing of digital rod position indication (DRPI) was in progress in accordance with Surveillance Test Procedure (STP) R-1C. Rod control bank B was being withdrawn. As the bank of rods was withdrawn, rod F2 DRPI indication remained at 0 steps. When the bank demand position indication exceeded rod F2's DRPI indication by greater than 12 steps, the reactor trip breakers were opened by manual reactor trip initiation. This action was taken to comply with the STP precautions to positively place the control rods in a known position, i.e. fully inserted. All systems actuated as required rods fully inserted, the main turbine automatically tripped.
"Manual initiation of a reactor trip where the actuation is not part of a pre-planned evolution is reportable under 10CFR50.72. (b) (3) (iv) (A) and 50.72(b) (3) (iv) (B) (1). While the reactor trip was initiated in accordance with the STPs precautions, the manual actuation was not an expected outcome of the STP.
"Subsequently, it was determined that rod F2 was indeed on the bottom as indicated by DRPI. A moveable gripper fuse was blown preventing that rod from being withdrawn. The blown fuse was replaced and testing continued in accordance with the outage schedule."
The NRC Resident Inspector was notified.