United States Nuclear Regulatory Commission - Protecting People and the Environment

Morning Report for April 8, 2004

Headquarters Daily Report

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Davis-Besse Synchronized to Grid


Dockets: 05000346
[1] B&W-L-LP
License No:

MR Number: 3-2004-0028
Date: 04/08/2004

RIII- Via Teleconf. with Site


This information is current as of 10:00 a.m. (EDT) on April 8, 2004. The plant is currently in Mode 1 at 100 percent power. At approximately 3:06 p.m. April 7, the plant experienced a loss of two non-essential 480V busses (E4 & E6) coincident with a loss of #1circulating water pump, due to the 13.8 kV feeder breakers to these loads tripping on instantaneous overcurrent. The operators performed the abnormal procedures for loss of condenser vacuum, loss of circulating water pump, rapid plant shutdown, and loss of AC power. The plant was stabilized with reactor power at 97 percent and electrical output reduced by about 30 MW. Per procedures, the circulating water system was aligned to operate using three of the four circulating water pumps, and the plant was returned to 100 percent power. The two 480V busses were verified to be fault free, and were re-energized from an alternate power source.

Resident inspector observations from the control room concluded that the operators' responses to expeditiously stabilize the plant in a safe condition were appropriate. The licensee established a problem-solving decision-making team to investigate the cause for the breakers tripping.

The Davis-Besse Oversight Panel will continue to monitor plant activities utilizing enhanced inspection oversight coverage. For non-routine evolutions occurring after normal working hours, enhanced inspection oversight coverage will continue to be expanded to monitor these activities.

Regional Action: For Information Only

Accession Numbers:

Accession No Accession Date
ML040990306 04/08/2004


Name Office Abbrev Phone No E-Mail
THOMAS, C S R3 (419) 244-4494 CST1@nrc.gov
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