Point Defect Model (PDM) has been successfully employed for aqueous solutions to describe the rate of surface corrosion of structural materials. In this work, the adaptation of PDM for the case of lead–bismuth coolant is developed. The necessary modifications in the set of electrochemical reactions and in the model of electrostatic potential distribution in the oxide film are made. Parameters of the proposed model, PDM_PB, are optimized using the experimental data for T91 grade steel. The obtained adaptation of PDM shows applicability to the case of lead and lead–bismuth coolants which is of critical importance for the next-generation fast-neutron reactors. •A Point Defect Model for steel oxidation by a heavy liquid metal coolant.•A set of interfacial reactions specific to the case of a liquid metal coolant.•Model of electrostatic potential distribution in the oxide layer.•Optimization of PDM parameters for T91 grade steel in contact with LBE.•Model verification via temperature dependence of the oxidation kinetics.