Home NRC Library Document Collections Events, Reports Associated with Event Notification Reports 2004

Event Notification Report for November 2, 2004

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
11/01/2004 - 11/02/2004

** EVENT NUMBERS **

Power Reactor	Event Number: 41164
Facility: RIVER BEND Region: 4 State: LA Unit: [1] [ ] [ ] RX Type: [1] GE-6 NRC Notified By: DAVID CLYMER HQ OPS Officer: CHAUNCEY GOULD	Notification Date: 11/01/2004 Notification Time: 02:13 [ET] Event Date: 10/31/2004 Event Time: 22:56 [CDT] Last Update Date: 11/01/2004
Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION	Person (Organization): GARY SANBORN (R4)

Unit	SCRAM Code	RX CRIT	Initial PWR	Initial RX Mode	Current PWR	Current RX Mode
1	N	N	0	Refueling	0	Refueling

Event Text

PLANT HAD AUTO START OF THE DIVISION 1 EMERGENCY DIESEL GENERATOR

"Undervoltage conditions were experienced on Division 1 emergency switchgear with subsequent start and load of the respective diesel generator [EDG]. A preliminary investigation indicates that an unexpected undervoltage signal was generated when technicians inadvertently contacted the wrong terminals during preparations for the respective division ECCS surveillance testing. All systems and equipment responded as required."

Power is still being provided (as of event reporting time) by the Division 1 EDG while they are working to restore normal power.

The licensee notified the NRC Resident Inspector.

Power Reactor	Event Number: 41165
Facility: RIVER BEND Region: 4 State: LA Unit: [1] [ ] [ ] RX Type: [1] GE-6 NRC Notified By: J. M. CLARK HQ OPS Officer: MIKE RIPLEY	Notification Date: 11/01/2004 Notification Time: 23:44 [ET] Event Date: 11/01/2004 Event Time: 16:44 [CST] Last Update Date: 11/02/2004
Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION	Person (Organization): CHUCK CAIN (R4) TONY VEGEL (R4)

Unit	SCRAM Code	RX CRIT	Initial PWR	Initial RX Mode	Current PWR	Current RX Mode
1	N	N	0	Refueling	0	Refueling

Event Text

EMERGENCY DIESEL GENERATOR AUTOMATIC START

"At 1644 [11/01/04], with River Bend Station in Mode 5 (Refueling), voltage on offsite power line Reserve Station Service (RSS) No. 2 was lost. This offsite power line is the 230 KV power supply to the Division 2, 4160 volt safety related electrical bus. The Division 2 emergency diesel generator (EDG) automatically started and loaded on a loss of voltage to the 4160 volt safety bus.

"At the time of the event, Division 2 Residual Heat Removal (RHR) was in the fuel pool cooling assist mode and the pump secured due to the loss of power. It was subsequently restarted and continues to provide the shutdown cooling function.

"The following systems were isolated as a result of this event: Reactor Water Clean-up, Alternate Decay Heat Removal, and Floor Drains.

"Investigation of the cause of the event is ongoing."

There was no impact on spent fuel pool level or temperature. At the event reporting time, power to the bus was still being provided by the Division 2 EDG with plans to restore normal power shortly. The licensee informed the NRC Resident Inspector. See also similar event EN # 41164 of 10/31/04.

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