The Savannah River Site is on pace to double-stack 358 canisters of treated radioactive liquid waste in this fiscal year, nearly double the 200 canisters stacked in fiscal 2017.
All told, the Department of Energy facility near Aiken, S.C., has to date double-stacked 457 canisters of waste in one of its Glass Waste Storage Buildings (GWSB). The project began in October 2016 after DOE officials at Savannah River realized they needed to create more space in the two structures used to store the canisters.
Liquid waste contractor Savannah River Remediation (SRR) still needs to double-stack 101 more canisters to meet the fiscal 2018 goal. The project costs about $3 million annually and could last up to seven or eight more years.
The SRS waste mission today covers roughly 35 million gallons of pretreated waste stored in underground storage tanks, a byproduct of the site’s nuclear weapons operations. About 10 percent of the total volume is sludge waste and the other 90 percent is salt waste. At the Defense Waste Processing Facility (DWPF) the waste is mixed with inhibitor materials and converted into a less harmful form suitable for interim storage on site.
The 10-foot-tall stainless steel waste canisters are then stored in GWSB 1. There were 2,254 one-canister storage positons in GWSB 1 when waste processing began in 1996. That capacity is being doubled to 4,508 spaces by modifying the holding slots.
When the double-stacking effort began in 2016, all of the canisters in GWSB 1 were moved to the second building to complete the modifications. The second building, GWSB 2, will continue storing canisters once the first building reaches capacity. There are no current plans to double-stack containers in that building.
The double-stacking method in GWSB 1 is expected to provide enough storage space in both buildings through 2029, and allow SRS to hold off on having to construct a third building. Assuming both buildings would have reached full capacity by then – and assuming canisters will not be double-stacked in GWSB 2 – that would create space for 6,762 canisters of waste.
Storage of treated waste at SRS is only a temporary solution as the federal government seeks a permanent repository for its defense nuclear waste. It is unclear what would happen if SRS reached capacity before a repository was established. But one consequence could be a temporary suspension of liquid waste processing since there would be no place to store the treated material. Overall, the Defense Waste Processing Facility is expected to fill more than 8,000 canisters of vitrified waste.
