Abstract The BERKUT module of the EUCLID/V1 integrated computer code has been developed for the performance analysis of fuel rods with nitride or oxide fuels of fast reactors using the quasi two dimensional approach. As far as the uranium-plutonium mixed nitride is considered as one of the basic nuclear fuel materials for the projects of advanced reactor facilities with liquid metal cooled fast reactors developed in Russia, the BERKUT module validation has been carried out against the experimental data observed in the in-pile mixed nitride fuel performance studies. The results of validation obtained taking into account the uncertainties of the fuel rod fabrication data, material properties, and irradiation conditions indicate that the BERKUT module adequately describes the mixed nitride fuel rod behavior in fast reactors.