Thermodynamic modeling of the phase composition of mixed uranium-plutonium mononitride under fast-neutron irradiation to burnup 80 GW·days/ton and temperature 900–1400 K

Thermodynamic modeling of the phase composition of mixed uranium-plutonium mononitride as a function of the burnup and temperature under irradiation by fast neutrons has shown that fission products accumulation results in the formation of a multicomponent uranium-plutonium mononitride based solid solution containing yttrium, zirconium and lanthanides as well as separate condensed phases U2N3, CeRu2, BaTe, Ba3N2, CsI, Sr3N2, LaSe, NbN, Mo, Tc, and U(Ru, Rh, Pd)3. The change in the content of these phases as a function of burnup to 80 GW·days/ton and temperature 900–1400 K is calculated. The position of the bottom phase boundary and stoichiometric coefficient of the solid solution are determined.