As the U.S. Dept. of Energy and its contractors rev up construction of permanent repositories for nuclear wastes now lingering in aging, corroded and heavily contaminated facilities at some of the agency’s former weapons-production sites, new technology is helping cleanup crews get at the nastiest and toughest-to-remove remnants.
At DOE’s Hanford site in eastern Washington, officials are using insect-like crawlers to prowl the radioactive floors of 177 enormous underground waste tanks (some holding up to 247,000 gallons), as well as massive retractable arms to methodically blast toxic sludge off the sides of those vessels. At least 53 million gallons of mixed nuclear and chemical wastes had been stored in 149 single-shelled tanks that date to the 1940s. Remaining liquids and other waste forms are being moved from the tanks into 28 newer and more secure double-shelled vessels on-site. From there, the waste will be vitrified—transformed into glass-like logs—for long-term site storage.