The U.S. Department of Energy will likely need an updated strategy sooner than anticipated for temporary storage of treated radioactive liquid waste at the Savannah River Site in South Carolina, according to the DOE Inspector General’s Office.
The department’s Office of Environmental Management (EM) did not properly assess the reliability of its strategy to store waste at Savannah River, Deputy Inspector General for Audits and Inspections Michelle Anderson wrote in a Feb. 19 letter to Assistant Energy Secretary for Environmental Management Anne Marie White. As a result, more storage space will likely be needed before the expected date of 2029, according to an audit report that accompanied the letter.
Roughly 35 million gallons of liquid waste is stored in more than 40 underground Cold War-era tanks at the Savannah River Site. Sludge waste accounts for 10 percent of that volume; the Defense Waste Processing Facility (DWPF) converts the material into a glassy, less harmful form suitable for interim storage at SRS. The treated waste is placed into Glass Waste Storage Buildings (GWSB) 1 and 2.
Since October 2016, liquid waste contractor Savannah River Remediation (SRR) has been creating extra storage space in GWSB 1 by double-stacking waste canisters. That required reconfiguring the waste storage slots to accommodate canisters to be stored on top of each other. The method has doubled the number of canisters the building can house, from 2,254 to 4,508.
The Inspector General’s Office said the Defense Waste Processing Facility is expected to produce 8,170 waste canisters, including roughly 4,200 generated to date. With double-stacking in Building 1, and normal storage in Building 2, the site will still need storage space for at least 1,310 more canisters.
The EM office was expected to offer a solution by 2029, but the report states one may be needed earlier because the double-stacking method has not been fully vetted.
While the maximum capacity in GWSB 1 is 4,508 spaces, that is a best-case scenario. Modifications have only been made to one area of the building, and it is unclear if the rest of the storage structure can successfully be altered for double-stacking.
In a response attached to the report, DOE said it is already addressing the issues raised by the inspector general.
