AIKEN, S.C. - The EM program at the Savannah River Site (SRS) recently finished double-stacking 100 canisters to increase onsite interim storage of glassified high-level waste.
Workers piled the canisters, one on top of the other, in 50 modified positions in the Glass Waste Storage Building 1 (GWSB1) at the Defense Waste Processing Facility (DWPF) in a project that began in August 2016.
They relocated existing canisters from GWSB1 to GWSB2 in fall 2015 to modify storage positions. Workers double-stacked relocated canisters plus newly poured ones.
Jim Folk, DOE-Savannah River Assistant Manager for Waste Disposition, said the project is a win for SRS.
“This innovative initiative is a game-changer in terms of interim storage space at SRS," said Folk.
The project increased storage capacity in GWSB 1 from 2,254 to 4,508 slots, allowing EM to postpone the expense of building another storage facility.
Approximately 200 canisters were removed from GWSB 1 to modify storage positions to accommodate two of the 10-foot-tall, 5,000-pound canisters.
The original storage positions hold one canister and have a 4-foot-thick concrete shield plug used to seal the opening at the top of each canister’s slot. To modify the 21-foot-deep slots, employees developed a remote cutting tool to remove the existing canister support crossbar.
After the modifications, the concrete shield plug is replaced by a thinner, galvanized cast iron shield plug, which will provide equivalent radiation shielding and structural support. In addition to the shield plugs, galvanized carbon steel support plates will be placed on the vault floor.
More than 300 canister support crossbars have been removed from the 2,254 slots, and 150 of them are ready to be double stacked. The project will continue to modify canister positions for up to eight years, as needed.
Waste from SRS underground tanks is received at DWPF, mixed with a borosilicate glass and heated to create a molten glass, which hardens when poured inside a stainless steel canister. The canister is temporarily sealed, the exterior is decontaminated and a weld seals it prior to transport. The canisters are transported and stacked using the shielded canister transporter, a specially designed vehicle for transporting a single canister to the storage building.
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.
Tom Foster, president and project manager of SRS liquid waste contractor Savannah River Remediation (SRR), said the canister double-stack project has been integral to keep canister production on track.
“Like all of the SRR innovations that have come to fruition, the canister double-stack project began as an idea and now we are seeing a milestone reached," Foster said. “Congratulations to the team members in DWPF who have dedicated themselves to seeing this project succeed."
Source: U.S. Dept. of Energy, Office of Environmental Management
