A viable program for treating supplemental low-activity waste at the Energy Department’s Hanford Site in Washington state can be developed for any one of three major technologies – vitrification, grouting, and steam reforming, according to an April 1 report from a National Academies of Sciences, Engineering, and Medicine panel.
But grouting and steam reforming would offer significant cost savings over vitrification, the report says. Grouting is the least expensive option, according to the panel.
The Waste Treatment Plant (WTP) being constructed by Bechtel National lacks capacity to convert all 56 million gallons of radioactive tank waste at the former plutonium production complex into a stable glass-like substance.
The fiscal 2017 National Defense Authorization Act required the National Academies to review another study ordered by Congress, led by the Savannah River National Laboratory (SRNL) in South Carolina, into supplemental methods to treat the low-activity waste stored in underground tanks at Hanford.
Perma-Fix Environmental Services has conducted a successful pilot in which it grouted 3 gallons of LAW and shipped it to Waste Control Specialists in Texas.
Steam reforming has the least developed track record, although it is intended to be used to immobilize sodium-bearing waste in the Idaho National Laboratory’s (INL) Integrated Waste Treatment Unit.
While one-tenth of Hanford’s waste is high-level radioactive waste (HLW) that will be made into glass, only one-third to half of the LAW will be vitrified during the plant’s 40 to 50 years of operation, the National Academies panel said. Low-activity waste accounts for 90% of the tank waste at Hanford, but only about 10% of the radioactivity.
