The environmental cleanup contractor at the Department of Energy’s Savannah River Site in South Carolina will start testing its newest supersize Saltstone Disposal Unit for potential leaks right after Thanksgiving.
BWX Technologies-led Savannah River Mission Completion will start a leak-tightness test at Saltstone Disposal Unit No. 8 (SDU 8) on Nov. 26, the company said in a Thursday press release.
The process that includes filling SDU 8 with about 34 million gallons of water, having subcontractor NSF International add 400 gallons of a fluorescent yellow/green dye and checking for any signs of external leaks, should be done in late December, according to the press release.
Once the leak test is done, SDU 8 will be drained and the dyed water will be discharged via a “controlled release” into an onsite tributary of the Savannah River, according to DOE and its contractor.
This is the same process DOE used to test for leaks at previously-constructed jumbo twins, SDU 6 and SDU 7, according to the release. The DOE broke ground on SDUs 8 and 9 at Savannah River near Aiken, S.C., in June 2019. Site work is also getting underway on the final three mega saltstone disposal units, SDUs 10, 11 and 12.
SDU 8 should be completed and handed over to operations in the spring of 2023 and could start receiving grouted salt solution by the end of 2023, said contractor spokesperson. The second layer of pre-stress cable has been installed at SDU. Survey and formwork installation continues for the lower mud mat at SDU 10 while excavation continues for SDUs 11 and 12 continues, the spokesperson said.
These big disposal units, 43 feet high and 375 feet around, are a key cog in the radioactive liquid waste disposal program at Savannah River. They can each hold about 34 million gallons of grouted, decontaminated salt solution, according to DOE.
After the Salt Waste Processing Facility removes strontium and cesium from liquid waste left over from nuclear weapons work, the concentrated high-level waste is sent to Savannah River’s Defense Waste Processing Facility where it is turned into a solid glass form and placed into canisters. The decontaminated salt solution, less-radioactive than the liquid waste from which it is separated, is blended with cement-like grout at the nearby Saltstone Production Facility for disposal onsite in the SDUs.
