Specialists at Russia’s AA Bochvar Research Institute of Inorganic Materials (VNIINM, part of Rosatom’s TVEL fuel company) have  developed samples of experimental fuel claddings made of a composite material based on silicon carbide, TVEL said. The work is part of a programme to develop new generation accident tolerant fuel, which will significantly improve the safety of nuclear power plant operation.

Materials based on silicon carbide have high mechanical strength, wear resistance, thermal conductivity, as well as corrosion and radiation resistance, but at the same time they are brittle and have low plasticity. The composite shells created by VNIINM scientists have unique plastic properties. Silicon carbide fibre, developed at the institute, evenly redistributes the resulting load on the reinforcing high-strength woven fibe frame, making the shell as a whole three times more durable. 

Earlier, as part of this project, VNIINM specialists made composite shells of silicon carbide with continuous fibre and whiskers. A number of studies have been carried out, and the first complex characteristics have been obtained, including mechanical and impact properties. The required thermophysical properties, heat capacity, thermal conductivity, and linear thermal expansion were also obtained. Corrosion tests were carried out under various conditions, simulating the operating modes of the reactor under pressure in steam. The samples withstood all the experiments. 

“The properties obtained by us prove the practical possibility of producing fuel claddings from silicon carbide to accelerate the process of achieving technological readiness,” said Fedor Makarov, chief expert of the materials science and technology department of composite, magnetic and special materials at VNIINM.