Oregon Public Broadcasting

Workers at the Hanford Nuclear Reservation are using an old technology to pare down radioactive waste.

The five-story evaporator boils the waste and extracts water to reduce the sludge into a more concentrated form.

The evaporator heats dangerous tank waste to a little more than 100 degrees in a vacuum so that the water boils off.

Then the sludge is pumped into a double-walled underground tank.

Hanford workers are trying to get more of that waste out of aging single-walled tanks and into the more stable and newer double-walled ones.

Some of the steel and concrete tanks have leaked into the ground in the past.

Vikki Wagner is the project manager for Hanford contractor Washington River Protection Solutions. She says it takes about two years of study before waste can be processed at the plant.

Vikki Wagner: “We have to characterize all the chemicals, all the radioactive nuclides. We have to see whether it foams, kind of like potatoes on your stove. We don’t want it foaming.”

Wagner says the plant should finish processing about a million gallons of waste by the end of September.

There are about 53 million gallons of radioactive sludge stored at Hanford.