Event Notification Report for December 09, 2004
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
12/08/2004 - 12/09/2004
EVENT NUMBERS
41250
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor
Event Number: 41250
Facility: DIABLO CANYON
Region: 4 State: CA
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: SUSAN WESTCOTT
HQ OPS Officer: STEVE SANDIN
Region: 4 State: CA
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: SUSAN WESTCOTT
HQ OPS Officer: STEVE SANDIN
Notification Date: 12/09/2004
Notification Time: 07:48 [ET]
Event Date: 12/09/2004
Event Time: 02:04 [PST]
Last Update Date: 12/14/2004
Notification Time: 07:48 [ET]
Event Date: 12/09/2004
Event Time: 02:04 [PST]
Last Update Date: 12/14/2004
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 | N | N | 0 | Hot Standby | 0 | Hot Standby |
RPS ACTUATION WHILE SHUTDOWN DUE TO FAILED FUSE
"During performance of Surveillance Testing on Intermediate Range Nuclear detector, a control power fuse blew. The plant was in Mode 3, and received a Reactor Trip signal which opened the Reactor Trip Breakers. All rods were on the bottom prior to the trip signal. Testing of Intermediate Range. Detectors has been suspended pending investigation. The plant remains in Mode 3."
The licensee will inform the NRC resident inspector.
* * * RETRACTION FROM L. PARKER TO M. RIPLEY 2013 EST, 12/14/04 * * *
"This is a retraction of NRC Event # 41250 'RPS Actuation While Shutdown.'
"On December 9, 2004, at 0204 PST, with Unit 2 in Mode 3 (Hot Standby), during testing of Intermediate Range Nuclear Detectors, a control power fuse blew, resulting in an actuation signal, and causing actuation of the Reactor Protection System (RPS). The reactor trip breakers opened, however, since all rods were fully inserted, no rod motion occurred. At 0448 PST, this event was reported as an eight hour non-emergency notification per 10 CFR 50.72 (b)(3) (iv)(A).
"Based on a subsequent review of the event against NUREG-1022 Rev. 2, the actuation was confirmed to be INVALID due to a blown fuse and not an actuation of the intermediate range neutron flux detector.
"Furthermore, with the unit in Mode 3 with all rods on the bottom, the RPS actuation had no effect, as the safety function had already been completed.
"Therefore, the event is not reportable under 10 CFR 50.72 or 10 CFR 50.73, and the event notification is retracted."
The licensee notified the NRC Resident Inspector. Notified R4 DO (G. Pick)
"During performance of Surveillance Testing on Intermediate Range Nuclear detector, a control power fuse blew. The plant was in Mode 3, and received a Reactor Trip signal which opened the Reactor Trip Breakers. All rods were on the bottom prior to the trip signal. Testing of Intermediate Range. Detectors has been suspended pending investigation. The plant remains in Mode 3."
The licensee will inform the NRC resident inspector.
* * * RETRACTION FROM L. PARKER TO M. RIPLEY 2013 EST, 12/14/04 * * *
"This is a retraction of NRC Event # 41250 'RPS Actuation While Shutdown.'
"On December 9, 2004, at 0204 PST, with Unit 2 in Mode 3 (Hot Standby), during testing of Intermediate Range Nuclear Detectors, a control power fuse blew, resulting in an actuation signal, and causing actuation of the Reactor Protection System (RPS). The reactor trip breakers opened, however, since all rods were fully inserted, no rod motion occurred. At 0448 PST, this event was reported as an eight hour non-emergency notification per 10 CFR 50.72 (b)(3) (iv)(A).
"Based on a subsequent review of the event against NUREG-1022 Rev. 2, the actuation was confirmed to be INVALID due to a blown fuse and not an actuation of the intermediate range neutron flux detector.
"Furthermore, with the unit in Mode 3 with all rods on the bottom, the RPS actuation had no effect, as the safety function had already been completed.
"Therefore, the event is not reportable under 10 CFR 50.72 or 10 CFR 50.73, and the event notification is retracted."
The licensee notified the NRC Resident Inspector. Notified R4 DO (G. Pick)