Hanford evaporator prepares for tank waste treatment

December 23, 2021, 7:00AMRadwaste Solutions
A worker installing new waste transfer lines between Hanford’s large underground tanks and evaporator facility welds a secondary encasement on one of the lines. (Photo: DOE)

As the Department of Energy's Hanford Site prepares for around-the-clock operations for tank waste disposal, workers at the site's 242-A Evaporator are upgrading equipment used to remove water from the tank waste and the systems that transfer waste to and from large underground containers. The upgrades will also extend the evaporator’s service life.

“Using the evaporator to create waste storage space in the double-shell tanks allows us to continue to retrieve waste from single-shell tanks and strategically stage waste for the next era of cleanup at Hanford, treating tank waste via the Direct-Feed Low-Activity Waste Program,” said Delmar Noyes, assistant manager for the DOE's EM Office of River Protection (ORP) tank farms.

What the evaporator does: Located in Hanford’s 200 East Area near underground storage tanks and the Waste Treatment and Immobilization Plant, the evaporator boils waste at low pressure in steam heat to evaporate water from the waste. The resulting waste slurry is transferred back to the nearby AW double-shell tank farm for continued storage. The evaporated water is filtered and transferred to Hanford’s Effluent Treatment Facility for additional treatment and disposal.

Since its construction in 1977, the evaporator facility has removed more than 81 million gallons of liquid from Hanford’s tank waste. The facility, however, is currently not in the "Waste Volume Reduction operating mode" but will resume operations in 2022, according to the DOE.

Upgrades: ORP tank operations contractor Washington River Protection Solutions (WRPS) has installed new waste transfer piping connections, called nozzles, in the AW farm and the evaporator facility. To minimize worker exposure to radiation while installing the nozzles, the workers toiled from outside the evaporator facility to drill through 22-inch-thick reinforced concrete walls that provide shielding. Now, workers are making progress on the next phase of the project, installing new double-walled waste transfer lines, according to the DOE.

“Work is now focused on excavating trenches that are up to seven feet deep in some areas between the AW farm and the evaporator, and welding together sections of transfer lines. In all, workers will install more than 1,200 feet of transfer lines,” said Dustin May, project manager for WRPS.

Startup: The project is scheduled for completion by the end of 2022, ahead of the projected start date of tank waste treatment operations.

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