Hydrogen is known to have detrimental effects on the mechanical properties of zirconium and its alloys, mainly due the formation of brittle hydride phases. The behaviour of hydrogen dissolved in zirconium is not fully understood at the atomic scale. In particular, the influence of hydrogen on the behaviour of defects in zirconium still needs to be clarified. In this paper, we report a molecular dynamics study of hydrogen behaviour in zirconium using an improved Zr-H interatomic potential. We determined the diffusivity of hydrogen in zirconium, and the interaction of hydrogen atoms with a single or a pair of atomic vacancies. The computed hydrogen diffusion is found to be in good agreement with experimentally determined values. Our results also indicate that hydrogen interactions with vacancies in zirconium promote vacancy clustering. Moreover, hydrogen is found to substantially decrease the mobility of divacancies. From the present simulation findings, it is concluded that the presence and concentration of hydrogen impurities may have a significant influence on the evolution of irradiation-induced defects in zirconium alloys.

众所周知，氢对锆及其合金的机械性能有不利影响，主要是由于脆性氢化物相的形成。溶解在锆中的氢的行为在原子尺度上尚不完全清楚。特别是，氢对锆中缺陷行为的影响仍然需要弄清楚。在本文中，我们报告了使用改进的Zr-H原子间势能对锆中氢行为进行分子动力学研究。我们确定了氢在锆中的扩散率，以及氢原子与单个或一对原子空位的相互作用。发现计算出的氢扩散与实验确定的值高度吻合。我们的结果还表明，氢与锆中的空位相互作用会促进空位聚集。而且，发现氢大大降低了空位的迁移率。根据目前的模拟结果，可以得出结论，氢杂质的存在和浓度可能对锆合金中辐照引起的缺陷的演变具有重大影响。