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, which is the current approach for processing Hanford’s radioactive waste, the report says. Grouting would the least expensive option, the expert panel found.
A grouting facility, which would bind the waste into a cement-like substance, could be set up in eight years or less at a maximum estimated cost of $8 billion. By comparison, fluidized bed steam reforming, which converts tank waste into a powder or ceramic form, could take 15 years and $17 billion. Building another large-scale vitrification plant could take 15 years and up to $36 billion, the report says.
The Waste Treatment Plant (WTP) being constructed by Bechtel National lacks capacity to vitrify all 56 million gallons of radioactive tank waste at the former plutonium production complex into a stable glass-like substance. The $17 billion facility is scheduled by 2023 to begin processing low-activity waste, which represents 90% of Hanford’s total radioactive waste holdings but only 10% of its radioactivity.
Grouting has been used for waste at the Savannah River Site in South Carolina. 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.
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 low-activity waste and shipped it to Waste Control Specialists in Texas for disposal. In June 2019, the Energy Department told the Washington state Department of Ecology it was withdrawing its permit application to grout 2,000 gallons of Hanford waste in the second phase of what was then called the Hanford Test Bed Initiative.
Perma-Fix, which could not be reached for comment, has said the waste could be shipped to Tennessee for grouting, before sending it on to Texas. The Energy Department’s fiscal 2021 budget request includes no funding for the project, after receiving $10 million in fiscal 2020.
“They are currently not moving forward on it,” Ecology spokesman Randy Bradbury said in an email last week of DOE and Perma-Fix officials. “They’ve indicated that they may well renew the application, but we haven’t heard anything.”
The withdrawal means continuation of the project, now referred to by DOE as the Low-Level Waste Offsite Disposal project, is “now in doubt,” the National Academies report says.
Only one-third to half of the LAW will be vitrified during the Waste Treatment Plant’s 40 to 50 years of operation, the National Academies panel said.
The National Academies of Sciences report does not say which technology should be the top choice. However, it favors using the Savannah River National Laboratory research as a pilot or scoping study for a full comparative analysis of the three technologies. The comparative analysis should also consider disposal sites such as Hanford, WCS in Texas, and EnergySolutions in Utah.
