After several years of planning, the initial discard of uranium solution from the new Accelerated Basin De-inventory program at the Savannah River Site in Aiken, S.C., was successfully transferred to the SRS liquid waste program from the H Canyon Chemical Separations Facility, the Department of Energy said last week.
The newly implemented Accelerated Basin De-inventory (ABD) mission replaces the previous method of disposing of spent nuclear fuel (SNF) from the Site’s L Area Disassembly Basin through the H Canyon Chemical Separations Facility. The new process should reduce cost and speed up disposal, DOE wrote in a Tuesday press release.
The previous method involved dissolving, purifying and blending highly enriched uranium from spent nuclear fuel into low enriched uranium that could be used to produce fuel for commercial power reactors. ABD dissolves the spent fuel, as before, but then prepares the resulting dissolved solution for discard to Savannah River’s liquid waste program’s H Tank Farm.
Once received in the HTF, the solution is mixed with other sludge waste already stored in underground waste tanks. The sludge waste is turned into glass in the Site’s Defense Waste Processing Facility and then stored in stainless steel canisters in onsite interim storage until a federal repository is established.
“Taken as a whole, the processing and discarding success of ABD material is highly sensitive to technology development timelines, regulatory requirement impacts, and processing schedules throughout the material’s movement through SRS facilities,” Program Manager for SRS’s managing and operating contractor Savannah River Nuclear Solutions James Therrell said. “Integration between [Savannah River Nuclear Solutions] and [Savannah River Mission Completion] with support from the Department of Energy is paramount to ensure the processing systems and associated paperwork stay aligned and optimized in support of the mission.”
For material to be added into sludge, it must meet strict criteria to ensure the sludge is the right mixture and doesn’t exceed regulatory radioactivity limits. The increased amount of uranium in the sludge would have increased the radioactivity, meaning the sludge would have needed to be distributed into a greater number of glass canisters to remain within limits for each canister.
To avoid the use of additional canisters, the Department of Energy, SRMC, Savannah River National Laboratory, SRNS and other external stakeholders partnered to demonstrate that the needed increase was acceptable and safe in order to get the regulatory limit increased. “The safe storage of increased amounts of uranium in glass is an example of one of several major technology advancements that has led us up to this initial transfer,” Therrell said.
