Role of di-interstitial clusters in oxygen transport in UO2+x from first principles

作     者：D. A. Andersson T. Watanabe C. Deo B. P. Uberuaga 

作者机构：Materials Science and Technology Division Los Alamos National Laboratory Los Alamos New Mexico 87545 USA School of Chemical and Biomolecular Engineering Georgia Institute of Technology Atlanta Georgia 30332 USA Nuclear and Radiological Engineering Program George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology Atlanta Georgia 30332 USA 

出 版 物：《Physical Review B》 (物理学评论B辑：凝聚态物质与材料物理学)

年 卷 期：2009年第80卷第6期

页      面：060101(R)-060101(R)页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：DOE Nuclear Energy Fuel Cycle Research and Development (FCRD) Nuclear Energy Advanced Modeling and Simulation (NEAMS) Program Fuels Integrated Performance and Safety Code (IPSC) [LA0915090108] OBES Division of Chemical Sciences [W-7405] Seaborg Institiute at Los Alamos National Laboratory Los Alamos National Security, LLC National Nuclear Security Administration of the U. S. DOE [DE-AC52 06NA25396] DOE NERI-C [DEFG07-14891] 

主　　题：density functional theory diffusion interstitials Monte Carlo methods uranium compounds 

摘      要：Using density functional theory, we examine a recently discovered structure for di-interstitial oxygen clusters in UO2+x in which three oxygen ions share one lattice site. This di-interstitial cluster exhibits a fast diffusion pathway; the migration barrier for these clusters is approximately half of that for mono-interstitials. Using kinetic Monte Carlo, we calculate the diffusivity of oxygen with and without the di-interstitial mechanism as a function of x and find that oxygen transport is significantly increased for higher values of x when the di-interstitial mechanism is included, agreeing much more closely with experimental data. These results emphasize the importance of clustering phenomena in UO2+x and have implications for the evolution of UO2+x.