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Russian scientists research steel-vanadium-steel laminate for next-gen nuclear reactors
March 24, 2019
Source: ASM International
Materials scientists from the Russian National University of Science and Technology (NUST MISIS) announce that they have developed a unique steel-vanadium-steel sandwich material that is able to withstand temperatures of up to 700°C, hard radiation exposure, mechanical stress, and chemical exposure for a long period of time. The material was designed to be used in the shells of nuclear reactor cores.
“The ferritic steel provides corrosion resistance, and the vanadium alloy (V-4Ti-4Cr) provides heat resistance and radiation resistance sufficient to withstand the effects of the ultra-rigid environments of a nuclear reactor," says Aleksandra Baranova, research co-author, post-graduate student of NUST MISIS Department of Metallurgical Science and Physics of Strength.
The maximum operating temperatures of the fuel element shells in the new generation reactors reach 550 to 700°C. Sodium, the liquid metal coolant, acts outside. The loads created are much higher than those that the core shells of existing reactors can withstand.
To close the nuclear fuel cycle in a new generation fast neutron reactor, new structural materials that can provide a higher fuel burn-out are needed. These materials should withstand damaging radiation doses of up to 180-200 dpa (displacements per atom), instead of the maximum 100-130 dpa, that are typical for existing materials.
The researchers say that fabrication problems were solved by the use of complex deformation processes and heat treatment of three-layer billets. The process includes hot co-extrusion (pressing), radial forging, and joint rolling. As a result, a "transition zone" is formed at the boundary of the components, and the alloys diffuse into one another, which provides a high-strength bond.
The research team has reportedly managed to create a prototype of the core shell, which is a monolithic three-layer tube. Laboratory tests are said to show high mechanical strength of the composite at operating temperatures of up to 700°C. In the near future, the team plans to begin long-term studies for radiation resistance.
Industries and Applications | Nuclear Power
Materials Processing and Treatment | Composites Processing
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