First-Principles Study of the Influence of Zirconium on the Diffusion of Uranium Defects in Uranium Dioxide

1 Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610065, China
2 School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China
Correspondence to: Jun Wang, Jian-Chun Wu
Abstract
Zirconium is inevitably introduced into UO$_2$ during reactor operation. Here, the migration properties of uranium vacancies and interstitials in zirconium-doped uranium dioxide are studied by using density functional theory and the climbing-image nudge elastic band methods. We find that the doping of zirconium obviously reduces the migration barriers of defects in uranium dioxide. Further, we investigated the lattice distortion and electron transfer associated with the migration of uranium defects. The calculations of bond-length and pressure show that the small ionic radius of Zr$^{4+}$ is responsible for the reduction of the migration barriers of U defects.
PACS numbers: 61.72.J-, 61.72.U-, 66.30.-h, 71.15.Mb
Keywords: Uranium dioxide, Defect, Zirconium, Diffusion

 Search for

Indexed/Covered by