Development of a fuel element on the basis of the composition (Zr,U)N for a high-temperature reactor

Abstract

In order to create (Zr,U)N nitride fuel for the first time by direct nitridation of the Zr - 5; 10 % wt. U alloy at 2400°C, using the approach of the oxidative constructing, reproducing the shape of the original metal billet ceramics was obtained. In the process of high-temperature nitridation of the alloy, a decrease in the uranium content in the near-surface layer occurs with its simultaneous concentration in the unreacted metal phase, in which the formation of three-dimensional defects (cavity) is possible. After the process of complete nitridation of the alloy is completed and it is heated at a synthesis temperature in a nitrogen atmosphere, the collective recrystallization of zirconium nitride occurs, as well as leveling of the concentration of uranium nitride from the volume of the sample to its surface proceeds.