Nuclear reactor up and running again

YAKIMA – Washington state’s only commercial nuclear reactor went back into service at 100 percent power Tuesday, several weeks after it had to be shut down when an electronic device failed.

The Columbia Generating Station was shut down July 30 after a faulty electronic device caused a steam valve to close, which led to a pressure increase in the reactor. Since then, crews have repaired the device and performed maintenance on steam valves and other systems.

The plant was reconnected to the northwest power grid at about 8:15 p.m. Sunday and began a gradual ascent to full power. The plant was at 100 percent power at 7:30 a.m. Tuesday, Energy Northwest, the company that operates the plant, said in a news release.

Columbia Generating Station is a boiling water reactor that produces 1,150 megawatts of electricity, which is sold to the Bonneville Power Administration for the Northwest electricity grid.

BPA officials had calculated that the shutdown was costing roughly $1 million each day.

The shutdown at Columbia Generating Station occurred after an electronic device failed and closed one of the reactor’s four steamflow valves. The valves channel nuclear-heated steam to the turbines driving the generator.