Hodille E A, Byggmästar J, Ferro Y, Nordlund K
CEA, IRFM, F13108 Saint Paul Lez Durance, France.
Department of Physics, University of Helsinki, PO Box 43, FI-00014 Helsinki, Finland.
J Phys Condens Matter. 2022 Aug 1;34(40). doi: 10.1088/1361-648X/ac8328.
Molecular dynamics simulations are used to investigate the behaviour of D atoms at two interfaces between beryllium (Be) and beryllium oxide (BeO). After relaxation of the simulation cell, there are (a) localised defects at the interface and (b) a hexagonal misfit dislocation network creating a succession of compressed and expanded area from each side of the interface. The simulations between 750 K and 1500 K for tens to hundreds of nanoseconds show that both interfaces act as trapping sites for D atoms. The simulations also show that D atoms tend to migrate in the material where the hydrogen isotope solubility is the highest as predicted by thermodynamics. However, the simulations also shows that there are additional kinetic barriers (D trapping sites, Dformation/dissociation in BeO) that slow down the path to equilibrium. These additional kinetic barriers may influence the fuel retention and permeation in Be materials.
分子动力学模拟用于研究铍（Be）与氧化铍（BeO）之间两个界面处D原子的行为。模拟单元弛豫后，（a）界面处存在局部缺陷，（b）一个六边形错配位错网络从界面两侧形成一系列压缩区和膨胀区。在750 K至1500 K之间进行数十至数百纳秒的模拟表明，两个界面均充当D原子的俘获位点。模拟还表明，正如热力学所预测的，D原子倾向于在氢同位素溶解度最高的材料中迁移。然而，模拟也显示存在额外的动力学障碍（D俘获位点、BeO中D的形成/解离），这些障碍减缓了达到平衡的路径。这些额外的动力学障碍可能会影响Be材料中的燃料滞留和渗透。
