According to Pacific Northwest National Laboratory (PNNL), dangerous radioactive waste can be trapped inside solid glass
In an experiment, researchers at PNNL, which is a part of the U.S. Department of Energy (DOE), mixed low-activity radioactive waste with liquid glass and suspended it to harden into a durable and solid material. This vitrification process with very small concentrations of radioactivity, immobilized the radioactive and chemical materials within the glass.
The experiment conducted at PNNL’s Radiochemical Processing Laboratory used around 11 liters of low-activity waste from a tank at the Hanford Site. The site is a decommissioned nuclear production complex located next to PNNL in southeastern Washington. The team defines this experiment as major step toward the goal of treating millions of gallons of hazardous waste generated at the site. The Hanford Site produced plutonium for around 40 years for the U.S. defense program. The team trapped the hazardous liquid waste in glass by mixing it with glass-forming materials such as silica. The mixture was later pumped into a melter that reached 2,100 degrees Fahrenheit. The process yielded around 9 kilograms of glass.
Moreover, when the glass broke during the test, it yielded multiple pieces of glass. The waste components are chemically bound as a part of the glass material. As the gradual dissolution of the glass depends of surface area, some minor cracking demonstrated small effect on leaking into the environment. The team is focused on performing a second vitrification test on around 7.5 liters of waste from a different tank at Hanford. However, the researchers stated that the waste is expected to test different filtration- and ion-exchange methods. After the completion of the test, the low-activity waste glass containers is expected to be stored in the Integrated Disposal Facility at the Hanford Site. The article was published in Live Science on May 21, 2018.