The Waste Treatment and Immobilization Plant, known as the Vit Plant, at southeast Washington’s Hanford Nuclear Waste Site, has hit another milestone on the way toward creating safe storage for the nation’s largest collection of radioactive waste.

Bechtel National has completed the project's structural concrete foundation and wall placements for the effluent management facility. The support facility will assist the Direct Feed Low-Activity Waste structure that plans turn the radioactive sludge into vitrified glass for long-term safe storage for the U.S. Dept. of Energy. The Vit Plant includes underground double-walled transfer pipes to concentrate secondary effluents generated during treatment of the off-gas from the Low-Activity Waste Facility melter.

“Finishing the effluent management facility main concrete foundation and walls is another sign of progress toward [facility] completion,” says Brian Reilly, Bechtel senior vice president and project director for the Vit Plant project. “Once the topping slab and protective floor coatings are complete, the next key steps are to receive the necessary permit authorization and begin installing process equipment and piping racks inside the building.”

The concrete work started in 2017 and includes more than 990 tons of reinforcing steel bar, 147 tons of embeds and 7,465 cu yds of high-strength concrete.

Once the Low-Activity Waste Facility, the WTP Analytical Laboratory and relevant support facilities are complete, Bechtel expects to start treating waste, even before the high-level waste facility gets finished.

Overall, the site needs to process and stabilize 56 million gallons of waste, a byproduct of national defense plutonium-production efforts during World War II and the Cold War era. Vitrification involves blending the waste with glass-forming materials and heating it to 2,100 degrees Fahrenheit. The molten mixture then gets poured into stainless steel canisters to cool and solidify. In this glass form, the waste is stable and radioactivity will safely dissipate over hundreds to thousands of years, according to the DOE.

Bechtel and the DOE expect to start treating waste in the low-activity facility by 2022.

Follow Tim Newcomb on Twitter at @tdnewcomb.