Effects of Zr doping on the surface energy and surface structure of UO2: Atomistic simulations

• Published in: Applied surface science 2015-10, Vol.351, p.517-523
• Main Authors: Xiao, Hongxing, Long, Chongsheng, Chen, Hongsheng, Tian, Xiaofeng, Wei, Tianguo, Zhao, Yi, Gao, Wen
• Format: Article
• Language: English
• Subjects: Distortion; Doping; Elevated; MD simulation; Molecular dynamics; Simulation; Surface energy; Surface structure; Zirconium; Zr-doped UO2
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2015.05.168

A shell-core model is applied to investigate the effects of Zr doping on the surface energies and surface structures of the three low Miller index surfaces in UO2 using the molecular dynamics (MD) technique. The surface energies and atomic structures of the Zr-doped and undoped UO2 (100), (110) and (111) surfaces are compared. Simulation results indicate that (i) the surface energy of (U1−yZry)O2 depend on the crystallographic orientation, as well as of undoped UO2. The (100) surface exhibits the highest surface energy, followed by the (110) surface, and the (111) surface; (ii) Zr doping will significantly increase the surface energy of UO2 by approximately 20% on (100) surface, 10% on (110) surface and 15% on (111) surface with the ZrO2 contents ranging from 0 to 12.5mol%, respectively; (iii) the surface energies of the three low Miller index surfaces decrease with increasing temperature both in undoped UO2 and in (U1−yZry)O2; (iv) the addition of Zr induces a severe distortion of the (U1−yZry)O2 surface structure, and the outermost top layer exhibits the strongest rumpling; (v) the considerable reconstructions can be observed in the two top layers of Zr-doped and undoped UO2 surfaces when the temperature is elevated to 900–1500K.