Refueling Columbia Generating Station

​​​​​​​​Columbia Generating Station’s 25th refueling outage (R-25) begins May 8, 2021, and is scheduled for 40 days. About 1,450 skilled workers, hired locally and from across the country, will join Energy Northwest’s workforce of about 1,000 employees to support refueling and maintenance projects. The work conducted during the refueling outage ensures high levels of equipment reliability is maintained.


Workers will replace 260 of 764 nuclear fuel assemblies in Columbia’s core with new fuel. Fuel that has been in the reactor core for six years will be placed in the used fuel pool, which removes residual heat from the assemblies. After a minimum of five years in the pool, the assemblies are moved to Columbia’s on-site dry cask storage, where they are stored securely in above-ground, 185-ton, concrete and steel, dry-storage casks. There are currently 45 casks on site, containing most of Columbia’s 36 years of used fuel.


R-25 maintenance projects

• Replace a low pressure turbine rotor
• Replace reactor water cleanup heat exchangers and piping 
• Refurbish a condensate pump and motor
• Replace a service water pump and motor
• Clean and inspect the circulating water basin and piping


COVID-19 preparation


The U.S. nuclear industry has successfully refueled numerous nuclear plants during COVID-19, while maintaining the health and safety of their workforce. Energy Northwest has a designated team leading our R-25 pandemic preparation and has incorporated industry best practices in our planning.


• Daily health screenings
• Self-scanning temperature stations
• Facility barriers and signage
• Staggered work times
• Reinforcement of expected behaviors
• Personal protective equipment
• Additional janitorial staff
• Outdoor break areas



R-25 Fact Sheet and Frequently Asked Questions​

​Electricians perform checks on a main steam isolation valve.

Workers move a spent fuel bundle from the reactor core into the spent fuel pool.