• Development of oxygen/corrosion products mass transfer model and oxidation-corrosion model for nuclear core analysis. • The oxide layer distribution of assemblies is consistent with the power distribution with the uniform mass flow. • The corrosion rate of the oxide layer in the core is low in the inlet region but increasing greatly in the active zone. A species mass transfer and an oxidation-corrosion model are developed and implemented into a novel code KMC-SUBtra-MC. It can be used to analyse oxygen/corrosion product distribution and oxidation-corrosion interactions in the lead-alloy cooled reactor core. The code solves the simultaneous equations of fluid mass, momentum, energy, elements transfer, and oxidation-corrosion. It is validated and verified by the experimental data and Computational Fluid Dynamics (CFD) simulation results. Then, it is applied to the analysis of the lead-cooled reactor core of M 2 LFR-1000.