The US Department of Energy has authorised the start of 'hot' or radioactive operations at the Salt Waste Processing Facility at its Savannah River Site (SRS). The first-of-a-kind facility will process 31?million gallons (117 million litres) of radioactive salt waste currently stored in underground tanks at the South Carolina location.

DOE's approval - five months ahead of the current baseline completion date of January 2021 - signals project completion and the transition from project phase to operations, the DOE Office of Environmental Management said. The facility has been designed and built, and will initially be operated, by Parsons Corporation. It is expected to start normal operations later this year after hot commissioning is complete.

Parsons CEO Chuck Harrington said: "The innovations of SWPF will forever change how we remediate nuclear waste and ensure that a cleaner, more sustainable and environmentally sensitive world is possible for the future."

SRS was constructed during the 1950s to produce the basic materials used in the fabrication of nuclear weapons, primarily tritium and plutonium-239. Five reactors were built on the site as well as support facilities including two chemical separations plants, a water extraction plant, a nuclear fuel and target fabrication facility and waste management facilities. The removal of salt waste - which makes up over 90% of the liquid waste now stored in so-called 'tank farms' - is key to the cleanup and remediation of the site.

The SWPF will separate highly radioactive waste - mostly caesium, strontium, actinides and waste slurry - from the less radioactive salt solution, and is the last major piece of the liquid waste system at SRS, according to the Office of Environmental Management. The concentrated high-activity waste will then be vitrified at the a nearby processing facility, while the decontaminated salt solution will be mixed with cement-like grout and placed in saltstone disposal units (SDUs) on site.

Up to now, the salt wastes have been being treated in interim processing facilities at Savannah River, but the commissioning of the SWPF will significantly increase processing rates.

"The startup of SWPF and the increased treatment capacity will save billions of dollars in overall operational costs by reducing the number of years needed to accomplish the nuclear remediation mission," Chris Alexander, executive vice president and engineered systems market leader for Parsons, said. It is expected that nearly all of the salt waste inventory at SRS will be processed by 2030.