Headquarters Daily Report
APRIL 05, 2000
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REPORT NEGATIVE NO INPUT
ATTACHED INPUT RECEIVED RECEIVED
HEADQUARTERS X
REGION I X
REGION II X
REGION III X
REGION IV X
PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION II APRIL 5, 2000
Licensee/Facility: Notification:
Virginia Power Co. MR Number: 2-00-0010
North Anna 1 2 Date: 04/05/00
Richmond,Virginia
Dockets: 50-338,50-339
PWR/W-3-LP,PWR/W-3-LP
Subject: UNIT 2 MANUAL TRIP ON POWER LOSS TO "C" REACTOR COOLANT PUMP AND
FAIURE OF UNIT 1 "H" EMERGENCY DIESEL GENERATOR TO START
Discussion:
This provides information related to NRC reported event numbers 36857 and
36864. On April 4, the Unit 2 reactor was manually tripped from 8 percent
power due to de-energization of a reactor coolant pump. Personnel
performing a clearance to support work on the SST removed fuses from the
wrong circuit. This de-energized the reactor coolant pump. The unit was
in the process of starting up after an automatic trip on April 3 due to a
ground fault on the power cable from the station service transformer
(SST). Unit 2 safety-related equipment performed as expected. The 2J
emergency diesel generator (EDG) started and re-energized its emergency
bus.
On Unit 1 the clearance error resulted in a power loss to the only
operating reactor coolant pump and the 1H emergency bus. Unit 1 was in
mode 5 after core reload during a refueling outage. At the time of the
event, shutdown cooling was being provided by the A residual heat removal
(RHR) pump which was powered from the 1H emergency bus. When the 1H EDG
failed to start, the operator manually started the B RHR pump. Shutdown
cooling was interrupted for approximately 2 minutes. Power was restored
to its pre-event configuration in less than two hours and the reactor
coolant pump was restarted.
Inspection of the 1H EDG discovered lube oil on top of all 12 lower
pistons. Preliminary analysis indicates that the lube oil hydraulically
locked the engine. The licensee is still investigating the cause of the
lube oil being on the pistons.
Regional Action:
Routine followup by the resident inspectors.
Contact: L. GARNER (404)562-4552
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