New material made for next-generation nuclear

Materials World magazine
11 Mar 2019

Russian scientists have created a three-layer alloy that could withstand prolonged use inside new ‘fast reactor’ nuclear plants. 

Based at the National University of Science and Technology MISIS (NUST MISIS), in Moscow, Russia, the team developed a steel-vanadium-steel sandwiched material for use inside nuclear reactor rod enclosures. 

The new fast reactors reach operating temperatures of up to 700°C and use sodium as a liquid heat carrier. This, plus the rods having direct contact with uranium, creates an extremely adverse operating environment and loads to endure. The existing rods in use have been unable to perform under these heightened conditions, so researchers have been pursuing an effective alternative. 

In order to create the closed-loop fuel cycle, a new reactor rod material was needed that would have high temperature, radiation and mechanical stress resistance. And today, NUST MISIS announced that the team has successfully developed a composite tube that can remain impervious at joints. 

‘The material's vanadium alloy guarantees heat and radiation resistance, so as to offset the impact of a nuclear reactor's super-aggressive environment,’ said NUST MISIS project co-author and postgraduate student Alexandra Baranova. 

‘It became possible to solve this problem by using a complicated deformation-thermal method for treating the three-layer blanks that includes hot coextrusion, radial forging and joint rolling,’ he added. ‘This creates a transitional zone on the boundary between the component materials. Therefore, the materials diffuse into each other and this guarantees their highly durable seams and joints.’ 

Already proven to withstand temperatures of up to 700°C, the team now plans to test the composite’s radiation tolerance, and continue trials into its usage with the aim of implementing it in next-generation nuclear plants.