Trials on the slate for this winter will follow-up successful tests, announced last week by the Department of Energy, of the first melter at the Hanford Site’s Waste Treatment and Immobilization Plant.
Conducted on Oct. 26 and Oct. 30, the tests consisted of melting glass beads together to be poured into a cylindrical canister. The most recent test was on a low-activity waste melter. Low-activity wastes make up about 90% of the liquid waste byproducts of plutonium production stored in Hanford’s underground tanks.
The October tests marked “another important step in commissioning the plant with test glass as we prepare for immobilizing radioactive and chemical waste in glass for safe disposal,” Mat Irwin, assistant manager for the Waste Treatment and Immobilization Plant Project for the Department of Energy, said last week in a written statement.
Hanford has 56 million gallons of radioactive waste in 177 underground tanks, including 28 double-shell tanks. The Waste Treatment Plant will convert a portion of that into a more stable, glass-like substance suitable for long-term storage and, eventually, permanent disposal.
The next step will be to test non-radioactive substitute wastes in the melter before running tests on actual tank wastes in early 2025, according to an email from a DOE spokesperson last week. The agency’s legal deadline to operate two low-activity waste melters at full capacity is 2025.
The two low-activity waste melters have expected lifespans of five years, and backup melters are already lined up to replace them, according to DOE.
Currently, DOE’s deadline to have its high-level waste melters online is 2033, but that deadline could slip rightward.
At one point, the legal deadline to finish solidifying Hanford’s waste was 2019. However, that year, and in a cost estimate published a year ago, DOE listed the end-date for liquid waste cleanup as 2069.
DOE’s current cleanup agreements with the state of Washington call for removing all the waste from the single-shell tanks and closing those tanks by 2043 and closing the double-shell tanks by 2052.
A new set of official deadlines could show up in an agreement that will be publicly unveiled after DOE and the Washington Department of Ecology finish reviewing the details. Neither party has said when that might be, though they did announce in May that they had reached a “conceptual agreement.”
The first direct feed low activity waste campaign at Hanford’s Waste Treatment Plant will solidify 40% to 50% of the site’s low-activity wastes, depending on who is doing the estimating. A second low-activity waste plant is under consideration. Alternatively, DOE and the state might choose to use a second low-activity waste disposal method, including the potentially cheaper remedy of solidifying wastes in a cement-like grout.
The only two spots in the United States capable of storing grouted tank wastes from Hanford are an EnergySolutions site in Clive, Utah, formerly known as EnviroCare, and a Waste Control Specialists site in Andrews County, Texas.
These sites are not over aquifers. Hanford is on top of a huge aquifer leading to the Columbia River. The possibility of grout being unable to contain radioactive substances for as long as glass has made the state leery about storing grout for thousands of years above an aquifer.
