WATERFORD, Conn. -- A failed electrical circuit card caused a shutdown of the Millstone 3 nuclear reactor on Sunday, power plant owner Dominion said yesterday.
The electrical circuit card caused the operating systems to shut down the reactor automatically as it detected a signal of low steam pressure in a secondary system, Richmond, Va.-based Dominion said.
Steam safety valves functioned properly, except one valve that closed later than operators expected, Dominion said. The valve will be replaced before the unit is restarted.
Based on an analysis of the steam flow, Dominion declared an alert, the second-lowest of the four US Nuclear Regulatory Commission's emergency classifications.
''We should finish our preliminary report in the next few days, assist the NRC team with its independent inspection and be prepared to return the unit to service shortly," said J. Alan Price, Millstone site vice president. ''Above all else, we will ensure the unit is safe to operate before we return it to service."
The NRC said it has begun an inspection of the shutdown.
The Connecticut Coalition Against Millstone yesterday asked Price for a public presentation to explain what occurred on Sunday.
''The reports Dominion issued were contradictory at best," wrote Nancy Burton, a leader in the opposition to Millstone.