RICHLAND – Workers at the Northwest’s only commercial nuclear power plant are nearly midway through the longest refueling outage in the 26-year history of the plant, which has come under added scrutiny in recent weeks following the nuclear crisis in Japan. Refueling outages at Columbia Generating Station are generally scheduled for spring because Bonneville Power Administration gets plenty of electricity from the melting snowpack fueling the hydroelectric dams. The shutdown of the plant, which is located on the Hanford Nuclear Reservation, is allowing for replacement of one-third of the plant’s uranium fuel rods and its condenser. The refueling outage began April 6 and is scheduled to end June 15. Brad Sawatzke, chief nuclear officer for Columbia Generating Station, estimated the new condenser would add 12 megawatts of output to the plant just through increased efficiency. The 1,150-megawatt plant provides about 3 percent of the region’s power, roughly enough electricity for 1 million homes. “The refueling is going very well for us,” he said during a plant tour Tuesday. “In addition, we’re doing a lot of maintenance on our equipment that we can’t do when we’re operating.” Columbia Generating Station is operated by Energy Northwest, composed of 28 member utilities. About 1,800 people from across the country have been brought in to work at the plant, more than doubling the plant’s regular work force. The nation’s 104 nuclear plants generally stagger their refueling outages so that workers can travel from one plant to another during the year for work. This year, those plant shutdowns have overlapped, making it harder to find workers, said Carl Golightly, who helped lead the tour. “Forty percent of the people we bring in are new to nuclear power,” he said. “Normally we’re the last spring outage. We don’t normally have a problem, but this year it’s been a challenge.” As a boiling water reactor, Columbia Generating Station shares a similar design with the Japanese reactors crippled by the earthquake and tsunami. The Northwest also is prone to earthquakes, and the plant sits next to the heavily-dammed Columbia River to draw water to cool the reactor. However, Sawatzke said the plant was built to withstand a magnitude 6.9 earthquake, and it sits above the flood zone should the dams fail.