In a bench-scale demonstration, researchers have successfully used a continuous process to turn 11 L of low-activity radioactive and hazardous chemical waste into a durable glass form. The project marks the first-time researchers have used the process to vitrify waste from underground storage tanks at the U.S. Department of Energys former weapons plant at Hanford, Wash. Previous tests had been done in batches. The waste remains from nuclear weapons plutonium production stretching back to before the Cold War, and several of the tanks are leaking. More than 20 years in preparation, the continuous approach is designed to become a key part of a treatment chain to address some 210 million L of liquid and semisolid waste held in 177 tanks. The system being constructed at Hanford will use a filtration and ion exchange system to remove solids and caesium from tank waste and pump the resulting low-activity waste to large melters. In additional experiments, off-gassed material from the vitrification demonstration will be concentrated and grouted to determine if it can be stabilised.
Chemical & Engineering News, 21 May 2018 ; http://pubs.acs.org/cen/news