Northwest's only nuclear plant resuming operation

RICHLAND, Wash. (AP)-- The Northwest's only nuclear power plant is reconnecting to the regional power grid after an unplanned shut down.

The Tri-City Herald reports ( ) that the 1,190-megawatt Columbia Generating Station resumed late Saturday night.

Energy Northwest says power levels and slowly rising and should reach 100 percent within 72 hours of restarting.

The plant shut down following a malfunction at a substation.

The newspaper reports that the malfunction caused the line that connects the plant's main output transformers to the substation to reject the load. A primary breaker opened too slowly and a secondary system kicked in and opened other breakers, causing the plant to separate itself from the grid and shut down.

Columbia Generating Station sends enough power to the Northwest grid to power a city the size of Seattle.