EM and its liquid waste contractor at the Savannah River Site (SRS) are now adding more capacity to store vitrified liquid waste, a significant federal cost-savings initiative at SRS.
Office of Environmental Management
February 4, 2025
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The canister double-stack team at Savannah River Mission Completion comprises members of the construction craft crew, engineers, radiological control inspectors, project managers and more. The team is modifying additional storage positions in a second glass waste storage building to accommodate two canisters stacked atop each other, a space-saving project that saves tens of millions of dollars.
AIKEN, S.C. — The U.S. Department of Energy Office of Environmental Management (EM) and its liquid waste contractor at the Savannah River Site (SRS) are now adding more capacity to store vitrified liquid waste, a significant federal cost-savings initiative at SRS.
Crews modified the first canister storage positions inside Glass Waste Storage Building (GWSB) 2 in December. Since then, they have fully modified 150 positions.
This milestone continues the undertaking to accommodate stacking two canisters of vitrified high-level waste from the Defense Waste Processing Facility (DWPF) one atop the other in GWSB 2. Double stacking began at GWSB 1 in 2016 and saves the federal government an estimated $100 million or more by avoiding construction of a third canister storage building. Modifying GWSB 2 saves the government another $100 million.
Savannah River Mission Completion (SRMC), the SRS liquid waste contractor, is completing this innovative project for EM to ensure there is enough onsite storage space for the projected 8,100 canisters to be produced at DWPF, according to the SRS Liquid Waste System Plan. SRMC completed modifications of all canister storage positions to accommodate double stacking in GWSB 1 in March. More than 2,400 canisters have been placed in double stacked locations in that building so far.
To achieve double-stack modifications, crews use a specially designed cutting tool to remotely remove an existing steel crossbar from each canister support in the below-grade vaults. The elevated crossbar is replaced with a plate that rests on the vault floor. This technique increases the height available to allow the 10-foot-tall canisters to be stacked one on top of the other. Crews have already cut more than 230 of the crossbars to prepare for the full modifications in GWSB 2.
Jim Folk, DOE-Savannah River assistant manager for waste disposition, said safely optimizing canister storage space at SRS is necessary to keep the liquid waste mission moving toward completion.
“The canisters from the Defense Waste Processing Facility are the final output from the sludge waste processing of the tank waste,” Folk said. “If we run out of space to safely store the canisters, the liquid waste processing system will stop. Thank you to the teams who are ensuring that doesn’t happen and for supporting the Department in our commitment to keep moving forward safely and efficiently.”
The canister double-stack project at the Savannah River Site modifies each canister storage position to provide enough room to add a second canister on top of the first. Double stacking canisters in both onsite storage buildings saves an estimated $200 million by deferring the expense of constructing another storage building.
At DWPF, the waste is mixed with a special glass and heated to more than 2,000 degrees Fahrenheit, turning the mixture into molten glass in a process called vitrification.
Current plans are to modify three of the four below-grade vaults in GWSB 2 for double stacking canisters. Once completed, this strategy will increase the total storage capacity to 8,619 canisters. The option of modifying the fourth vault would be available, if necessary, and would increase the total storage capacity of both buildings to 9,204 canisters.
The canisters are safely stored in below-grade concrete vaults in the glass waste storage buildings until a federal repository for high-level waste is established.
A specially designed vehicle, called the shielded canister transporter, is used to move the canisters from the DWPF vitrification building to the glass waste storage buildings. It is also used to move the canisters for the double-stacking process.
SRMC President and Program Manager Dave Olson said successful expansion of the canister double-stack project into GWSB 2 is an example of continuous improvement at work.
“What started as an innovative and challenging idea sprung from a small team of engineers has turned into one of the largest cost savings in our program for the Department of Energy,” Olson said. “Innovative ideas taken from inception to execution, with double stacking canisters as just one example, is a testament to the ingenuity of this team.”
The radioactive liquid waste that is vitrified inside the canisters was generated at SRS as by-products from processing nuclear materials for national defense, research, medical programs and NASA missions. The waste — totaling 33 million gallons — is stored at SRS in two groupings of underground waste tanks known as tank farms.
-Contributor: Colleen Hart