Sixteen single-shell tanks built to hold liquid radioactive waste at the Energy Department’s Hanford site near Richland, Wash., will not be closed in 2019 as once scheduled, under a tentative agreement finalized last week.
These underground tanks in Hanford’s Waste Management Area C have been emptied but must still be either removed from the site, or filled up with concrete to prevent rainwater from trickling in and spreading any radioactive or toxic contaminants within to the area’s groundwater.
One of those two things was supposed to happen in 2019, under the Tri-Party Agreement that governs Hanford cleanup. Now, the cleanup milestone is “to be established,” according to the eight-page tentative agreement dated Nov. 29 and signed by Washington state and DOE officials. The Washington state Ecology Department posted the document online Thursday.
DOE will submit a pair draft closure plans, including schedules, to Washington state by March 31, 2017, according to the new tentative agreement.
Waste from the 16 single-shell tanks, which have a history of leaks, was mostly transferred to sturdier double-shell tanks.
In total, there are 149 single-shell tanks and 28 double-shell tanks at Hanford, holding some 56 million gallons of liquid waste generated by Cold War-era plutonium production for the Pentagon’s nuclear arsenal. Ultimately, this waste will be solidified in glass canisters created in the Waste Treatment Plant Bechtel National is building. Treatment of all tank waste must begin by 2036, a federal judge ruled in April.
