This work proposes a kinetic study of Zirconium alloy when working under controlled temperature and pressure conditions to simulate pressurized water reactor (PWR) conditions. A detailed analysis of the experimental results allowed to describe each time constant observed on the impedance diagrams. A model based on the PDM including the anodic and cathodic reactions and the description of the interfacial capacitance is proposed and allows to fit the experimental results. Even if the overall oxide film formed on the alloy can reach several micrometers in thickness, only a compact oxide sub-layer of a few nanometers contributes to the impedance response.