Clean-up activities continue at the US Hanford Site with demolition of the K West Reactor Annex that was used to transfer radioactive sludge away from the Columbia River. The Department of Energy’s (DOE’s) Office of Environmental Management (EM) said the demolition of is another key step toward clearing the former plutonium production reactor.

The project includes draining and removing the reactor’s used-fuel basin where the sludge was stored, then placing the reactor building in interim safe storage. “The annex building accomplished its mission to support the safe packaging and transfer of sludge from the basin in 2019,” said Mark French, EM Richland Operations Office Division Director for Hanford’s Central Plateau Clean-up Project. “Now, removal of the facility allows us to continue the progress we’ve already made to reduce risk in Hanford’s K Area and along the river.”

Crews with EM contractor Central Plateau Clean-up Company (CPCCo) have been moving and sorting radioactive debris into underwater bins in the 1.2m-gallon basin since last summer. Workers using underwater cameras and specialised tools place the contaminated material into steel tubes, which will be filled with grout, a concrete-like substance, and removed during basin demolition.

Workers recently finished installing a system to pump out and filter the contaminated water from the basin. They will transfer the water to Hanford’s Effluent Treatment Facility by tanker truck for disposal. Testing activities on the system are currently underway, with the draining of the basin expected to begin by the end of this year.

“While we still have plenty of work to do, it’s exciting to see how far we’ve come,” said Mike Kruzic, CPCCo 100 K Closure Projects Manager. “I’m proud of our team and their continued focus on safety over speed.”

Following removal of the used fuel basin, workers will construct a safe storage enclosure over the main K West Reactor building, a process known as “cocooning”. The enclosure will protect the building while the radioactivity in the deactivated reactor core decays over the next several decades, making it safer to complete disposition of the reactor in the future. K West will be the eighth and final Hanford reactor to be cocooned following the cocooning of the nearby K East Reactor in October 2022.

The K East and K West reactors and associated used fuel storage basins were built in the mid-1950s in support of Hanford’s plutonium production mission. The fuel storage basins provided temporary storage of irradiated fuel discharged from the reactors prior to shipment to fuel processing facilities at the Hanford Site. The site is home to approximately 56m gallons of radioactive tank waste stored in 177 underground tanks, representing one of DOE’s largest environmental risks and most complex challenges. The tank waste is a result of nearly five decades of plutonium production during World War II.

Image courtesy of Hanford Site