29 Jan (NucNet): The first Russian-made experimental nuclear fuel assemblies based on accident-tolerant fuel, or ATF, have been loaded for testing into the water loops of the Mir research reactor at the State Research Institute of Atomic Reactors in Dimitrovgrad, southwest Russia, state nuclear fuel company Tvel said.
Tvel said the testing is a part of a project to develop Russian fuel that is resistant to severe beyond-design basis accidents and bring it to the market.
The two experimental fuel assemblies, manufactured at the Novosibirsk Chemical Concentrates Plant in southwest Siberia, consist of fuel rods for Russian pressurised water reactors, or VVERs, with four different combinations of cladding materials and matrix.
Fuel pellets are made from one of the two materials, either traditional uranium dioxide or uranium-molybdenum alloy with increased density and thermal conductivity. The fuel rod cladding is either a zirconium alloy with chromium coating or a chromium-nickel alloy.
Each assembly contains 24 fuel rods with different combinations of materials. The assemblies are being tested in the Mir reactor under conditions as close as possible to reactor operational conditions.
Tvel said the research reactor’s design enables parallel studies in separate loops, which is especially important given the simultaneous fuel testing for reactors of Russian and foreign design.
The first phase of the tests will be completed this year. The next stage of the project will see the loading of experimental fuel assemblies with some ATF fuel rods into a commercial power reactor in Russia.
Mir, a pool/loop-type research reactor, is designed mainly for testing fuel elements, fuel assemblies and other core components of different types of operating and under-development nuclear power reactors.
The nuclear industry says accident tolerant fuels have the potential to transform the safety and operation of nuclear plants and the goal is to begin deploying them in the early to mid-2020s.
They are designed to endure the loss of active cooling in a reactor core for much longer than current fuel types.
