STIGA (Silicide fuel Ternary Investigation using Genetic Algorithms)
Silicide fuels are considered as candidates both for GEN IV reactors and for current generation reactors, as a way to increase the residence time and safety margins, due to their high uranium density and thermal conductivity. However, many properties still need to be determined with precision before they can be introduced in the reactors. One of the critical ones is whether or not ternary phases will be created with fission products (FP). This information is complicated to access from experiments since the number of FP is large, and considering their combination and concentration increases the number of cases tenfold. In this project, we propose to use the genetic algorithm USPEX to create the structures of U3Si2-FP ternary compounds with different stoichiometries that will be investigated by means of ab initio electronic structure calculations, using VASP and the framework DFT+U. In that way, both the stability and concentrations are investigated. After this study, it will be possible to know whether modelling properties such as swelling, thermal conductivity or even fuel-pellet chemical interaction needs to consider the ternary phases.