The H Canyon Chemical Separations Facility at the US Savannah River Site (SRS) in South Carolina has begun dissolving nuclear fuel from Japan’s Fast Critical Assembly as a step towards its safe disposal. This followed years of work by the US Department of Energy (DOE) Office of Environmental Management (EM), including preparation by multiple site contractors and replacement of an electrolytic dissolver and its support equipment.
The electrolytic dissolver system was designed and built by SRS in the 1960s. Replacing it required extensive planning, testing and engineering to revitalise this unique capability. Janice Lawson, Senior Vice President of EM Operations for Savannah River Nuclear Solutions, explained that Fast Critical Assembly fuel is different from the other material processed in H Canyon because it is coated in stainless steel cladding, rather than aluminium. “The other dissolvers in the canyon are chemical dissolvers that use nitric acid to process the fuel; however, nitric acid alone doesn’t work on stainless steel,” she said.
This is not the first time H Canyon has performed electrolytic dissolution. From 1969 to 1980, the facility used this method for fuel clad in stainless steel and zirconium. The fuel is lowered into a nitric acid solution, and electricity is used to dissolve the stainless steel cladding and fuel. This produces a liquid that is sent through the site’s liquid waste facilities, where it is made into glass through the process of vitrification. It is then safely stored onsite until a federal repository is identified.
“I’ve had the privilege of seeing this material arrive at the site in 2016 as well as the opportunity to oversee the progress and hard work it took to get to the point of dissolution,” Lawson said. “The team has faced a lot of hurdles to get here, but have used their ingenuity, capacity for teamwork and their vast knowledge to make this happen. This is a big day for the Department of Energy, National Nuclear Security Administration (NNSA), the Japan Atomic Energy Agency, Savannah River Site and the entire nation.”
The Japan Atomic Energy Agency sent the reactor’s plutonium fuel along with funding for the disposition to SRS, fulfilling a pledge by Japan and the US to remove all separated plutonium and highly enriched uranium from the reactor in Japan. The fuel is currently stored onsite and is being transferred to the canyon for dissolution on a prescribed schedule. The entire campaign is expected to take 18 to 24 months.
“We appreciate the employees of H Canyon, K Area, Savannah River National Laboratory, Savannah River Mission Completion and Centerra for their partnership and commitment to this non-proliferation mission,” said Virginia Kay, NNSA director of the Office of Plutonium Disposition. “Preventing nuclear weapons proliferation and reducing the threat of nuclear and radiological terrorism around the world are key US national security strategic objectives. The startup of this mission is a testament to the ability of SRS to handle the nation’s critical nuclear materials challenges.”
