A system-wide liquid waste processing outage at the Savannah River Site (SRS) is still expected to last through the end of the year, as workers continue to make strides in other key areas of the Energy Department facility’s liquid waste mission.
The site reported in February that it was halting all liquid waste processing due to the failure of Melter 2: a 65-ton refractory-lined melting vessel that functions as part of the Defense Waste Processing Facility (DWPF), which converts the site’s radioactive waste into a solid glass form for storage.
The suspension is expected to last through the rest of the year as SRS prepares to activate Melter 3 at the facility. That process includes connecting the melter to DWPF, modifying the piping so waste can be easily transferred to DWPF from other waste facilities, and conducting any related maintenance work, a DOE spokesperson said by email Wednesday.
Liquid waste contractor Savannah River Remediation (SRR) has removed Melter 2 from the DWFP and plugged in its replacement, according to an Aug. 17 DOE press release. All told, the melter replacement project is expected to cost $3 million, and will take the rest of the year, the spokesperson said.
The Defense Waste Processing Facility is designed to treat over 30 million gallons of sludge and salt waste stored in more than 40 waste storage tanks, a byproduct of Cold War nuclear weapons operations at SRS. Melters combine the waste with a mixture known as borosilicate frit to remove contamination. When heated in the melter, these elements form a molten glass, which is then poured into stainless-steel canisters for safe storage.
Though liquid waste processing has halted at SRS, the site is moving forward with related missions, primarily preparing the Salt Waste Processing Facility (SWPF) for a December 2018 startup. Once complete, the SWPF is expected to increase waste processing at the site from 1.5 million gallons per year to 6 million gallons.
SWPF construction was completed in June 2016; the DOE spokesperson said Wednesday the plant is about 58 percent complete with testing and commissioning. “The project is currently completing system operational testing and integrated system operational testing. We are preparing for the receipt and introduction of chemicals to support the cold commissioning phase of the project,” the spokesperson said. SWPF construction cost $2.3 billion, about $65 million under the target cost when construction began in 2012.
About 90 percent of the SRS tank volume is salt waste; the rest is sludge waste. Until SWPF is ready, the site will continue using the Actinide Removal Process, which extracts radioactive isotopes from the salt waste including cesium, strontium, and actinides. Those isotopes are sent to the nearby DWPF where, like the sludge, they are mixed with a sand-like glass transferred to canisters for temporary storage on site. The decontaminated salt waste is sent to the SRS Saltstone facilities for permanent storage. The sludge waste is temporarily being stored on site until DOE names a permanent repository.
