High-temperature processing of nitride spent fuel. Theoretical foundations. Part I

High-temperature processing (HTP) of nitride spent nuclear fuel (SNF) is a series of head-end operations, as a result of which the fuel cladding is removed and the main components of the fuel (uranium and plutonium) are converted into pressable UO2 and PuO2 oxides. Based on the properties of uranium nitrides and oxides, a high-temperature processing (HTP) scheme for nitride spent nuclear fuel is proposed. This scheme consists of nitriding, denitriding, cladding separation, uranium oxidation to U3O8, and subsequent reduction to UO2. Theoretical and thermodynamic justification for each HTP stage is provided.