Event Notification Report for November 23, 2007
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
11/22/2007 - 11/23/2007
EVENT NUMBERS
43804
Power Reactor
Event Number: 43804
Facility: PALO VERDE
Region: 4 State: AZ
Unit: [1] [] []
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: THOMAS WEBER
HQ OPS Officer: JASON KOZAL
Region: 4 State: AZ
Unit: [1] [] []
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: THOMAS WEBER
HQ OPS Officer: JASON KOZAL
Notification Date: 11/24/2007
Notification Time: 01:08 [ET]
Event Date: 11/23/2007
Event Time: 22:26 [MST]
Last Update Date: 11/24/2007
Notification Time: 01:08 [ET]
Event Date: 11/23/2007
Event Time: 22:26 [MST]
Last Update Date: 11/24/2007
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(i) - PLANT S/D REQD BY TS
10 CFR Section:
50.72(b)(2)(i) - PLANT S/D REQD BY TS
Person (Organization):
JEFFREY CLARK (R4)
JEFFREY CLARK (R4)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 70 | Power Operation |
TECHNICAL SPECIFICATION REQUIRED PLANT SHUTDOWN DUE TO INOPERABLE LOAD SEQUENCER
"The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73.
"On Friday, November 23, 2007, at 22:26 Mountain Standard Time (MST) Palo Verde Nuclear Station Unit 1 initiated a normal reactor shutdown to comply with Condition H of Technical Specifications (TS) Limiting Condition for Operation (LCO) 3.8.1.
"TS LCO 3.8.1 requires that automatic load sequencers for train A and B be operable in Modes 1, 2, 3 and 4. The shutdown is necessary due to an inoperable automatic load sequencer for train A in Unit 1. The train A automatic load sequencer was declared inoperable on November 22, 2007, at 19:30 MST and was not restored to operable status within the TS required 24 hour completion time of Condition F of TS 3.8.1. TS 3.8.1 Condition H requires the plant to be placed in MODE 3 within 6 hours and MODE 5 within 36 hours if the required actions and associated completion time of TS Condition F are not met. Efforts are in progress to correct the condition.
"The event did not result in the release of radioactivity to the environment and did not adversely affect the safe operation of the plant or health and safety of the public."
The licensee is taking measures to evaluating the extent of this condition from the remaining automatic load sequencers for Units 1, 2 and 3. The inoperability was discovered due to an invalid actuation of the A train load sequencer that resulted in a pond spray pump initiation.
The licensee notified the NRC Resident Inspector.
"The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73.
"On Friday, November 23, 2007, at 22:26 Mountain Standard Time (MST) Palo Verde Nuclear Station Unit 1 initiated a normal reactor shutdown to comply with Condition H of Technical Specifications (TS) Limiting Condition for Operation (LCO) 3.8.1.
"TS LCO 3.8.1 requires that automatic load sequencers for train A and B be operable in Modes 1, 2, 3 and 4. The shutdown is necessary due to an inoperable automatic load sequencer for train A in Unit 1. The train A automatic load sequencer was declared inoperable on November 22, 2007, at 19:30 MST and was not restored to operable status within the TS required 24 hour completion time of Condition F of TS 3.8.1. TS 3.8.1 Condition H requires the plant to be placed in MODE 3 within 6 hours and MODE 5 within 36 hours if the required actions and associated completion time of TS Condition F are not met. Efforts are in progress to correct the condition.
"The event did not result in the release of radioactivity to the environment and did not adversely affect the safe operation of the plant or health and safety of the public."
The licensee is taking measures to evaluating the extent of this condition from the remaining automatic load sequencers for Units 1, 2 and 3. The inoperability was discovered due to an invalid actuation of the A train load sequencer that resulted in a pond spray pump initiation.
The licensee notified the NRC Resident Inspector.