H、He离子辐照对国产ZIRLO合金氧化膜的影响

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

针对国产ZIRLO合金开展了H、He离子辐照对其腐蚀性能影响的研究。对国产ZIRLO合金样品分别进行高温(300℃)H、He离子辐照试验,辐照峰值剂量为1dpa,之后进行模拟一回路腐蚀试验。通过腐蚀增重方法得到腐蚀动力学曲线。利用慢正电子湮没多普勒展宽谱对未辐照样品和辐照样品进行微观结构表征,用透射电子显微镜对腐蚀125d的样品进行微观结构表征。结果表明,H、He离子辐照并未改变ZIRLO合金的腐蚀机理。He离子辐照产生的空位团可促进腐蚀过程中裂纹形核,增加了氧扩散通道,减少氧扩散激活能,导致腐蚀初期有明显的加速效应。H离子辐照对腐蚀的加速现象不如He离子辐照明显,原因是H离子辐照产生H-空位复合缺陷对氧扩散激活能减少作用较小。

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.