Work crews at the Department of Energy’s Savannah River Site in South Carolina are starting what DOE dubs a “leak-tightness” test on its fifth super-sized saltstone disposal unit (SDU) at the federal complex near Aiken, S.C.
Starting Monday, Oct. 27, environmental contractor Savannah River Mission Completion was to begin running the test on SDU-10, DOE said in an Oct. 23 press release. The test is designed to ensure the newly-built SDU-10 can safely hold up to 33 million gallons of solidified, decontaminated salt solution.
Over the following three-to-four weeks, the BWXT-led contractor will fill the new SDU with 33 million gallons of dyed water, enough to fill 55 Olympic-sized swimming pools. This will enable the crews to spot any signs of leaks on the outside.
The testing could take up to eight weeks, DOE said in the release. Once the test is done, SDU 10 will be drained, and the environmentally-safe dyed water will be discharged to onsite drainage basins for a controlled release, the department said.
SDU 10 is the fifth mega-volume SDU at Savannah River. Saltstone Disposal Units 6, built in 2017, and SDU-7 are in already in operation, the department said. In the release. SDUs 8 and 9 are approved for operation. The others used the same leak tightness tests as SDU 10, DOE said.
DOE said in June 2024 that the jumbo-sized SDUs over their lifespan, should provide the feds with hundreds of millions of dollars in cost saving compared to the previously planned 80 smaller SDUs.
According to DOE, SDUs receive decontaminated salt solution processed at the onsite Salt Waste Processing Facility. Dry materials are mixed with the salt solution at the Saltstone Production Facility (SPF) to form a grout. The grout is pumped to the above-ground SDUs where it hardens into saltstone.