Northwest's only nuclear plant back to full power

RICHLAND, Wash.  — The only nuclear power plant in the Northwest has returned to full power after an unplanned shut down.

The Tri-City Herald reports the plant began reconnecting to the regional power grid late Saturday night and returned to full power Tuesday morning.

The plant shut down Dec. 18 following a malfunction at a substation.

The newspaper reports 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.