AIKEN, S.C. (August 14, 2023) – The U.S. Department of Energy Office of Environmental Management (EM) has marked a major achievement in the effort to expand interim storage of canisters of vitrified high-level waste at the Savannah River Site (SRS) while saving taxpayer dollars.
The Savannah River Site reached a landmark achievement with the placement of 2,000 double-stacked canisters of vitrified high-level waste. Savannah River Mission Completion uses the Shielded Canister Transporter to move the canisters into modified underground storage locations, creating twice the storage space in existing storage facilities.
Savannah River Mission Completion (SRMC), EM's liquid waste contractor at SRS, has double-stacked 2,000 canisters in one of the site's two Glass Waste Storage Buildings (GWSB). GWSB 1 consists of below-grade seismically qualified concrete storage locations containing support frames for vertical storage of 2,262 10-foot-tall canisters.
An evaluation in 2015 concluded that, with some minor changes to each vertical location, two canisters could be stored in an area previously used to store only one.
While combined storage space from the original design of both buildings would hold a total of 4,602 canisters, the modifications will allow for moving two canisters into each storage location, freeing the remaining existing space for future use. By doubling the original space in the two storage buildings, SRMC is deferring, and potentially eliminating, the need for construction of another GWSB and saving approximately $100 million.
Jim Folk, DOE-SR assistant manager for waste disposition, said the double-stack program is expected to provide enough storage space until a federal repository is established.
“The double-stack program is making better use of the existing storage space we have, enabling us to keep the liquid-waste mission moving forward,” Folk said.
Double-stacking is made possible by the removal of a steel crossbar at the bottom of each canister support, along with reducing the thickness of the plug that is used to safely seal each canister position. Modifying the metal support frame required workers to develop and test a cutting tool that could be operated from a distance to minimize the potential of workers’ exposure to radiation.
The SRS Liquid Waste Program had previously filled nearly 4,400 cans with high-activity waste, now occupying a large percentage of the storage locations in the site’s two GWSBs. Consolidating the existing stored canisters into the modified locations will effectively double the number of positions available to hold canisters in the two facilities. Enough positions are planned to be converted to allow storage of all canisters produced at SRS.
SRMC President and Program Manager Dave Olson said this innovative approach is solving a storage problem.
“To reach this point has required re-thinking, re-designing and re-constructing our approach to the task of temporarily storing these waste canisters,” Olson said. “Achieving 2,000 double-stacked canisters exemplifies the dedication to continuous improvement that will help us disposition the remaining liquid waste at SRS and complete the overall mission. I am proud of this team’s effort.”