This graphic shows the innovative concept for the canister double-stack project. Each current canister position is being modified to accommodate two canisters per existing slot.
The first two canisters stacked on top of each other. In the bottom photo, the first canister sits on the crossbar. In the top photo, the second canister is positioned on top of the first canister.
AIKEN, S.C. – EM began double-stacking radioactive canisters recently at the Savannah River Site (SRS), part of an innovative effort to increase onsite interim storage capacity of glassified high-level waste.
A shielded canister transporter is used to stack two canisters in the Glass Waste Storage Building (GWSB) 1 at the Defense Waste Processing Facility (DWPF). Savannah River Remediation, the SRS liquid waste contractor, is conducting the process.
To modify the canister positions to accommodate two, 10-foot tall canisters, SRS employees developed a remote cutting tool to remove the existing canister support crossbar.
SRR engineers created the tool for less than $120,000 — approximately 25 percent less expensive than commercial ones.
DOE-Savannah River Assistant Manager for Waste Disposition Jim Folk said the project is a win for SRS and for saving taxpayer money.
“At DOE, we want to see safe, creative solutions to solve issues,” Folk said. “Finding this new method for canister storage is a game-changer in terms of finding new storage space that will save tens of millions of dollars.”
SRS has removed more than 250 of 2,254 crossbars, and 150 of those have been prepared for double-stacking, including installation of a new support plate and shield plugs. The project will continue to modify canister positions for up to eight years, as needed.
Double-stacking increases the storage capacity in GWSB 1 from 2,254 slots to 4,508 slots, creating adequate safe interim canister storage until at least fiscal 2029 and postponing the expense of another storage facility estimated to cost $74 million.
The radioactive canisters contain vitrified waste produced at DWPF. High-level waste from SRS waste tanks is received at DWPF, mixed with a borosilicate glass and heated to create a molten glass, which hardens when poured inside the stainless steel canister. The canister is temporarily sealed, the exterior is decontaminated, and a weld seals the canister prior to storage transport.
The canisters are destined for a future federal repository, but pose no technical or radiological issues staying at SRS in this interim double-stack storage arrangement, according to engineering studies.