The Savannah River Site liquid waste tank farms hold less than 35 million gallons of waste for the first time since 1999, according to a Jan. 9 Facebook post from Savannah River Remediation (SRR), the Department of Energy facility’s liquid waste contractor.
Since taking over the contract in 2009, SRR’s goal has been to rid the site of more than 36 million gallons of radioactive waste that dates to the Cold War era. “Reducing the risk posed by legacy liquid waste, the byproduct of decades of work processing nuclear materials for national defense, is a key mission,” SRR stated in the Facebook post.
SRR has operationally closed eight of the site’s 51 waste storage vessels by removing hundreds of thousands of gallons of liquid waste from each tank, and then pouring a cement mixture into the empty tanks. The waste removal process includes mixing the radioactive material with water to mobilize the waste, making it easier to remove.
About 90 percent of the tank volume is salt waste, and the rest is sludge waste. The two components undergo a separations process so they can be treated separately.
The sludge waste is processed at the site’s Defense Waste Processing Facility (DWPF), which mixes the material with a sand-like glass and transfers the final product to canisters suitable for temporary storage at SRS. Eventually, the canisters will be sent to a repository for permanent storage, but the federal government has not yet named such a location.
Meanwhile, the salt waste is treated using the Actinide Removal Process (ARP), which extracts radioactive isotopes from the salt waste including cesium, strontium, and actinides. Those isotopes are sent to to DWPF where they undergo the same process as the radioactive sludge. The decontaminated salt waste is sent to the SRS Saltstone facilities for permanent storage.
Salt waste processing is expected to ramp up once the Salt Waste Processing Facility (SWPF) goes online. The facility was completed in June and is now being tested and commissoined. Site officials say that once SWPF becomes operational in late 2018, waste processing will jump from 1.5 million gallons per year to 6 million.
In 2015, the Energy Department revised its schedule for completion of liquid waste cleanup from 2042 to 2065, with costs surging to $25 billion more than the original estimate. Cost projections reported at that time were between $91 billion and $109 billion.
SRR’s two-year, $797 million contract extension will end in June. The contractor initially signed, in 2009, a six-year, $3.3 billion contract with an option to tack on the two additional years.
