Trials of a new system that aims to reduce the volume of intermediate level waste (ILW) from the nuclear industry by up to 90% have been completed by Costain and collaborator Tetronics International.
ILW results from nuclear waste management and decommissioning, and includes materials such as radioactive sludge and contaminated equipment.
Costain said that it had worked with Tetronics to enhance its existing plasma furnace technology to vitrify such wastes and that the trials had “successfully demonstrated substantial volume reductions” when compared with alternative remediation approaches.
It said that the ability to greatly reduce the volume of ILW would immediately ease the burden on the UK’s waste storage facilities, which could mean considerable savings for building future storage areas and in other areas of ILW treatment. It claimed that billions of pounds could be saved by the nuclear industry over the coming decades, and that there was an added possibility of income through sale of the technology abroad.
Costain head of technology and consultancy Bryony Livesey said: “We are now consulting with the nuclear industry on what the next steps should be. We’re seeking to develop this further.”
The process involved putting ILW into a furnace which operated at around 1,000 to 1,400C and took between 6 and 12 hours to reduce waste to a glass-like substance.
Organic and carbonaceous material in the ILW was vaporised by the extreme heat produced by the plasma torches. The waste gas was then cleaned via a filtration process and released, with any secondary waste collected from filtration fed back into the reaction chamber of the furnace for vitrification.
Inorganic material in the ILW, together with additives that reduce its melting point and increase fluidity, formed a pool of melted material in a water-cooled container. The material was subsequently cooled to form a stable, vitrified waste.
It said that the solid material was physically and chemically stable over thousands of years and, had demonstrated very low levels of leachability.
Tetronics said that it had built the test facilities at Swindon over two years, with the trials taking two months.
The investment for the project was supported by the UK’s innovation agency, Innovate UK, with the Department of Energy and Climate Change and the Nuclear Decommissioning Authority (NDA) also contributing.