Comparison of H and He Ion Irradiation Impact on Oxide Film of Domestic ZIRLO

The corrosion behavior of domestic ZIRLO was investigated in 300 ℃ PWR-simulating loop after irradiation. Hydrogen and helium ions irradiation experiments were carried out at the temperature of 300 ℃, with the damage peak dose of 1 dpa using the injection energy of 100 keV and 150 keV respectively. The corrosion kinetics curve was obtained by measuring weight gain of the alloy. Irradiation defects of Zr matrix and microstructure of oxide film were determined by Doppler broadening spectra based on slow positron beam and transmission electron microscope. The results illustrate that irradiation does not change the corrosion mechanism of the zirconium alloy. Vacancy clusters produced by helium ions promote the nucleation of the cracks in the corrosion process, and generate extra channels for oxygen ions and the reduction of activation energy for oxygen diffusion, leading to the obvious acceleration effect in corrosion at the initial stage. While hydrogen ions irradiation has less acceleration effect on the corrosion compared with helium ions irradiation, because complex-defect pairs composed of vacancies and hydrogen ions have little effect on the reduction of activation energy for oxygen diffusion in corrosion process.