Headquarters Daily Report APRIL 05, 2000 *************************************************************************** REPORT NEGATIVE NO INPUT ATTACHED INPUT RECEIVED RECEIVED HEADQUARTERS REGION I REGION II REGION III REGION IV 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 _