Columbia Generating Station Begins 25th Refueling 5/8/2021 Rollup Image Page ContentEarly this morning, Energy Northwest operators disconnected Columbia Generating Station from the Northwest power grid to begin its 25th refueling outage. The biennial refueling is an opportunity to add fresh nuclear fuel to Columbia's reactor core, as well as perform maintenance projects that can be accomplished only when the reactor is offline.The Northwest's only nuclear power plant, which produced nearly 18 million megawatt-hours of electricity during the last two years, is scheduled to be offline for no more than 40 days. “During refueling, we'll complete essential work activities to ensure Columbia continues to produce reliable carbon-free power for the region, 24/7" said Grover Hettel, Energy Northwest chief nuclear officer.Energy Northwest and the Bonneville Power Administration time the plant's biennial refueling to coincide with spring snow melt and runoff that maximizes power output from the region's hydroelectric dams and minimizes the impact of taking Columbia offline. Nuclear and hydro are the region's only full-time clean energy resources.During the refueling, crews will replace 260 of the 764 nuclear fuel assemblies in Columbia's reactor core. Every two years, fuel that has been in the reactor core for six years is removed and placed in Columbia's used fuel pool, which removes residual heat. After a minimum of five years in the pool, the assemblies are moved to Columbia's on-site dry-cask storage. In addition to refueling, workers will install a 34-foot, 133-ton refurbished low-pressure turbine rotor as part of Columbia's life-cycle plan to satisfy the plant's license extension to 2043. In addition, workers will replace reactor water cleanup heat exchangers and piping; refurbish a condensate pump and motor; replace a service water pump and motor; and clean and inspect the circulating water basin and piping. In all, regular and temporary employees will complete more than 10,000 work tasks. Concerted, rigorous planning efforts begin two years prior to each refueling, and long-lead planning starts many years in advance. While always a major undertaking, planning during the last 14 months has also required additional COVID-19 pandemic measures. Columbia is one of the last nuclear reactors in the U.S. to complete it's refueling during the pandemic. “Our Energy Northwest team put together extensive plans and procedures for a successful refueling while keeping our workforce safe and healthy," Hettel said. “Our focus during the next several weeks is performing the work safely and getting Columbia back online to continue providing electricity that we're all counting on." More than 1,400 skilled, temporary workers were hired locally and from across the country to support refueling and maintenance projects at Columbia. The added workers join EN's normal workforce of about 1,000 employees and bring substantial economic value to the region. Columbia, located 10 miles north of Richland, will restart and reconnect to the Northwest power grid in mid-June. See the fact sheet and frequently asked questions about Columbia Generating Station's refueling outage for more details. About Energy Northwest Energy Northwest develops, owns and operates a diverse mix of electricity generating resources, including hydro, solar, battery storage and wind projects – and the Northwest's only nuclear power facility. These projects provide carbon-free electricity at the cost of generation – enough clean, cost-effective and reliable energy to power more than a million homes each year. As an independent joint operating agency of Washington state, Energy Northwest comprises 27 public power member utilities from across the state serving more than 1.5 million customers. The agency continually explores new generation projects to meet its members' needs.