AIKEN, S.C. (February 15, 2023) – The waste vitrification facility at the Department of Energy Office of Environmental Management’s Savannah River Site (SRS) has completed a processing improvement enabling safer operations and more efficient conversion of high-activity liquid waste into glass.
The Defense Waste Processing Facility (DWPF), operated by SRS liquid waste contractor Savannah River Mission Completion (SRMC), has resumed operations after an outage to remove formic acid from the DWPF vitrification process. The facility underwent two planned operational outages in the past eight months to implement the acid changeover. The second and final outage ended Jan. 31.
Formic acid has been replaced by glycolic acid, which allows for safer operations and higher production rates while maintaining chemical stability. Glycolic acid produces significantly less hydrogen and ammonia gases under extreme heat, making the workplace much safer for workers. The change also opens other opportunities for improvement that result in even higher production rates.
The increased production capability will help DWPF keep pace with the Salt Waste Processing Facility (SWPF), which is processing greater volumes of waste than ever before. In slightly more than two years of operation, SWPF has processed nearly 5 million gallons of salt waste and the SRMC team has already doubled the production rates demonstrated during the first year of production.
Jim Folk, DOE-Savannah River assistant manager for waste disposition, said the change to glycolic acid is consistent with efforts to accelerate waste throughput, which is the amount of waste processed through the facility, and reduce the risk posed by radioactive liquid waste stored at SRS.
“The conversion to glycolic acid will allow higher production rates at DWPF with the added benefit of increasing the overall safety posture for the facility worker and the Savannah River Site,” Folk said. “Our objective is to improve production while continuing to safely treat the remaining waste.”
During the most recent outage, SRMC took advantage of the processing downtime by making improvements across the entire liquid waste program. SWPF teams performed maintenance on multiple pumps, performed component replacements, and installed modifications to improve overall system performance.
At the nearby Saltstone Production Facility, where the decontaminated salt solution from SWPF is converted into grout, teams have rebuilt portions of the processing equipment and performed mechanical tie-ins to a recently built saltstone disposal unit.
At DWPF, the pause allowed for numerous tasks, including execution of the safety requirements that support the glycolic acid implementation and significant steam-systems work. Other equipment enhancements will enable the facility to maintain a higher production level as SWPF processes greater volumes of radioactive elements including plutonium.
Crews working at the site's underground waste storage tanks used the integrated outage to move the next sludge batch into the sludge feed tank, make repairs to the tank that receives decontaminated salt solution from SWPF, and begin solids removal from the DWPF recycle receipt tank.
Wyatt Clark, SRMC chief operations officer, said virtually all recent modifications at liquid waste facilities were made to help boost production safely.
“Protecting our workers is always our main objective,” Clark said. “As we strive to significantly increase treatment of waste throughout the liquid waste program, we will continue to focus on worker safety. I am very excited when our team can increase production while simultaneously offering greater protection at our facilities.”
The 43 active waste storage tanks at SRS currently contain approximately 35 million gallons of radioactive liquid waste produced as byproducts from the processing of nuclear materials for Cold War-era national defense, research, medical programs, and U.S. space missions. DWPF uses vitrification to convert the high-activity radioactive waste into a solidified glass form suitable for long-term storage and safe disposal.
Cutline: The Defense Waste Processing Facility at the Savannah River Site has completed the conversion from formic acid to glycolic acid in the waste vitrification process. Glycolic acid is expected to enable the facility to process greater quantities of high-activity waste while also improving efficiency and safety.