The longest refueling outage in the history of the Energy Northwest nuclear power plant began Wednesday.
The Columbia Generating Station near Richland powered down a couple days early on Saturday, but Energy Northwest decided to keep its planned outage schedule starting Wednesday.
The Bonneville Power Administration requested the early stop to operations because high water flows through the federal hydroelectric dam system would allow ample power production.
More than 1,800 workers have been hired to help with the planned 78-day refueling outage. They are in addition to 1,100 permanent employees at the plant.
Crews plan to replace 244 of the 764 fuel assemblies in the reactor core and perform maintenance.
The largest project -- accounting for the extended outage -- will be the replacement of the condenser, which turns steam from the turbines back into water for reuse. The work will cost $113 million.
The new condenser will provide up to 12 megawatts of additional power generation, paying for itself over time.