The Hanford site is tasked with the intricate challenge of disposing of around 56 million gallons of radioactive and chemical tank waste. The Department of Energy’s Office of Environmental Management (DOE-EM) considers this one of its most complex tasks.
This mission also represents the largest cost driver at Hanford, with current lifecycle cost estimates ranging from $199 to $496 billion. The current strategy for treating this tank waste involves removing it from Hanford’s 177 large tanks and separating it into high-level waste (HLW) and low-activity waste (LAW) streams for processing. The Waste Treatment Plant (WTP) will convert all the HLW and about half of the LAW into solid glass through vitrification. The vitrified LAW will be permanently stored at Hanford, while the HLW will be sent to the nation’s deep geological repository.
The method for treating and storing the remaining 15-20 million gallons of LAW, termed Supplemental LAW (SLAW), is still undecided. To address this uncertainty, DOE has initiated the Test Bed Initiative Phase II (TBI) 2,000-gallon Demonstration Project. This project aims to test the feasibility of alternative methods for treating Hanford’s SLAW, specifically grouting instead of vitrifying the tank waste, and storing it permanently at commercial disposal facilities outside Washington state. Grouting involves mixing the low-activity tank waste with a concrete-like material that solidifies and immobilizes the waste.
The Government Accountability Office estimates that grouting supplemental LAW could save up to $95 billion and significantly reduce the time needed to treat Hanford’s LAW. The insights gained from this demonstration will inform future decisions regarding Hanford tank waste treatment and storage. In April 2024, the U.S. Department of Energy (USDOE), Washington State Department of Ecology (Ecology), and U.S. Environmental Protection Agency (EPA) announced the landmark Holistic Negotiations Agreement outlining a “realistic and achievable plan” for cleaning up millions of gallons of radioactive and chemical waste from large underground tanks at the Hanford Site.
The changes reaffirm a shared commitment to the safe and effective cleanup of tank waste, including retrieving waste from 22 tanks in Hanford’s 200 West Area by 2040 and grouting the low-activity portion of the waste for offsite disposal.
