Department of Energy contractor Savannah River Remediation (SRR) announced on May 11 that it has completed a salt dissolution campaign in Tank 37, one of the underground tanks storing high-level radioactive liquid waste at the Savannah River Site (SRS) in South Carolina.
Salt dissolution is a process to dissolve hardened saltcake through water additions and mixing pumps and jets. Dissolving the solids into liquid allows the waste to be transferred to another tank for temporary storage before further processing through the liquid waste system.
SRR, the liquid waste contractor at SRS, said that the completion of the waste retrieval project further advances the DOE Office of Environmental Management’s (EM) mission priority of safely cleaning up its legacy radioactive liquid waste.
Creating tank space: The impetus for the Tank 37 salt dissolution was evaporator operations at Savannah River’s H Tank Farm. The use of evaporation reduces the volume of liquid waste in the underground waste storage tanks. Tank 37 is the “drop tank” for the site’s 3H Evaporator, meaning that the tank receives the concentrated salt from the evaporator output.
The 3H Evaporator operations had filled Tank 37 with concentrated salt, creating the need for additional tank space for more concentrated salt from the evaporator. According to SRR, dissolving the salt in Tank 37 provided the additional space while creating excellent feed to the Salt Waste Processing Facility (SWPF), operated by contractor Parsons.
Feeding SWPF: Jim Folk, the DOE’s assistant manager for waste disposition at SRS, said that the success of the Tank 37 campaign will contribute significantly to future SWPF batches.
“Processing 6 million gallons of SRS tank waste this year is an EM 2021 priority,” Folk said. “Producing high-quality salt batch feed from the tank farms means we are able to provide more material for processing at the Salt Waste Processing Facility, helping us meet this goal.”
Through 14 transfers, SRR dissolved more than 59 inches of salt from the tank, producing 830,000 gallons of high-quality salt solution.
Exceeding expectations: According to Mark Schmitz, SRR’s chief operating officer and deputy project manager, the Tank 37 salt dissolution project exceeded expectations.
“Savannah River Remediation achieved unprecedented salt dissolution success with Tank 37,” Schmitz said. “Not only did the SRR team dissolve more salt than originally planned, but we also finished the project one month ahead of schedule.”
SRR said that it implemented several innovative techniques to improve the salt dissolution campaign, including designing and developing enhanced mixing jets and deploying cameras during water additions and transfers to effectively target and reduce saltcake mounds.
Emptying and closing the waste tanks at SRS is part of EM’s Strategic Vision 2021–2031.