
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: WEDNESDAY, May 23, 1990                   TAG: 9005230624
SECTION: VIRGINIA                    PAGE: B-7   EDITION: EVENING 
SOURCE: Associated Press
DATELINE: SURRY                                LENGTH: Medium

REACTORS HALTED BY SHORT CIRCUIT

A short circuit in a transformer that disabled a backup power system resulted in the shutdown of both reactors at Virginia Power's Surry nuclear plant.

Virginia Power spokesman Carl Babb said the shutdowns took place shortly after noon Tuesday when a faulty fire-protection system activated and sprayed water on a transformer outside the Unit 1 reactor building. The Unit 1 reactor shut down automatically after the 8-foot-square transformer short-circuited and "flashed, arcing to the ground," said Baab, who compared the event to a blown fuse.

When the transformer arced, some of the electrical charge jumped to an overhead power line, about eight feet above the transformer. The overcharged power line short-circuited a second transformer that controls the backup power supplies to one water pump on each reactor. Each reactor has three water pumps for cooling.

Control-room operators almost immediately shut down Unit 2 after the automatic shutdown of Unit 1. The Unit 2 operators noticed the unstable voltage readings from the station's power loads and decided to close down Unit 2 as a precaution, Baab said.

There was no apparent damage to the two 781-megawatt reactors or the backup electrical system.

The Unit 1 reactor may be restarted by late today, and the Unit 2 reactor may be brought on-line within two or three days, Baab said.

The transformer is used to step-up the voltage of the electrical power coming out of the Unit 1 reactor from 20,000 volts to 230,000 volts so the power can be sent out over high-voltage power lines. When the transformer short-circuited, the power being generated by the Unit 1 reactor had no place to go, resulting in an automatic shutdown of the system, Baab said.

Virginia Power officials are unsure why the transformer's fire protection system sprayed water on the transformer or if that was what caused the accident. The transformers are outside fully exposed to rainfall, Baab said. Before the shutdowns, Unit 1 and Unit 2 had been operating for 151 and 180 consecutive days respectively.

by CNB