The chemistry and physics of modelling nitride fuels for transmutation

Against the background of increased interest in nitride fuel for transmutation of minor actinides, this paper presents the current status of UK modelling of nitride fuel pins. A new equilibrium chemistry model for nitride fuel, suitable for inclusion in fuel pin modelling codes, is described. High-temperature experiments on (U,Zr)N in a sealed capsule indicate that actinide nitrides in a nitrogen atmosphere are stable up to their melting point. The paper also recommends a set of physical and chemical properties for advanced nitride fuels, highlighting the areas where data are presently missing.