November 12, 2013
AIKEN, S.C. - Savannah River Remediation (SRR), the liquid waste contractor at the U.S. Department of Energy (DOE) Savannah River Site (SRS), has deployed a new solvent in the SRS salt waste treatment activities that is expected to remove more radioactive constituents and eventually improve salt waste production.
The new technology is called the Next Generation Solvent or NGS and replaces a solvent that has been used since the Interim Salt Disposition Process (ISDP) began operations in April 2008. Neil Davis, SRR Tank Farms Project Director, said the focus of the NGS deployment is to improve performance and to set the stage for future production rate increases.
"One of the characteristics that we are looking for is increased cesium removal because we can process more waste while disposing of less cesium in the State of South Carolina," Davis said. "This is a win-win for SRS and the State of South Carolina."
Salt waste inside SRS waste tanks comprises over 93 percent of the remaining waste. Removing the salt waste is essential in cleaning and operationally closing the tanks.
The ISDP system utilizes two facilities, the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Besides cesium, other radioactive constituents, such as plutonium and strontium, are extracted from the salt waste in these facilities. The extracted cesium, plutonium and strontium are sent to the Defense Waste Processing Facility, where they are mixed with radioactive sludge waste from the tanks through a vitrification process. The molten glass mixture is poured into stainless steel canisters that are being stored at SRS until a federal repository is developed.
Salt waste with more cesium removed will be sent to the SRS Saltstone facilities, where it will be blended in a cement grout mixture and stored at SRS as non-hazardous waste. Both extraction solvents were developed by the Oak Ridge National Laboratory in Tennessee, and both extract cesium. Full-scale testing has shown that NGS is more effective and extracts more cesium.
Terrel Spears, Assistant Manager for Waste Disposition Project, DOE-Savannah River Operations Office, called the NGS deployment an excellent development for all involved.
"This is another example of teamwork resulting in improved performance," Spears said. "The Department has high confidence in this new technology and looks forward to the end result, which is to reduce risk from the stored Cold War legacy waste."
Following the outage deploying the NGS, the ARP and MCU will begin operations early next year using the new solvent.
The Savannah River Site, located near Aiken, South Carolina, is owned by the U.S. Department of Energy. The SRS Liquid Waste contract is managed by Savannah River Remediation, a team of companies led by URS Corporation, with partners Bechtel National, CH2M Hill and Babcock & Wilcox. Critical subcontractors for the contract are AREVA, Energy Solutions and URS Professional Solutions.