(CexA1-x)2Ti2O7 (A=Y, Gd, Lu; x=0-1)的制备及离子束辐照效应研究

项目名称： (CexA1-x)2Ti2O7 (A=Y, Gd, Lu; x=0-1)的制备及离子束辐照效应研究

项目编号： No.11475076

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 李玉红

作者单位： 兰州大学

项目金额： 96万元

中文摘要： 高放射性核废物的安全处置是核能发展过程中必须首要解决的关键问题，也是全球高度关注的热点和难点之一，寻找理想的高放射性核废物固化基材是当务之急。本项目拟利用与高放射性核素Pu和U极相似的元素Ce来代替Pu和U进行Pu或U的陶瓷固化研究。在制备包容不同Ce含量稀土钛酸盐烧绿石(CexA1-x)2Ti2O7 (A=Y, Gd, Lu; x=0-1)的基础上，对其进行Ne离子和Xe离子束辐照实验研究；利用基于密度泛函理论的第一性原理软件VASP对包容有不同Ce含量的稀土钛酸盐烧绿石进行结构参数、电子结构以及溶解能的计算。通过采用分子动力学方法系统研究Ce包容量、A位稀土离子对离子束辐照所引起材料结构变化（体积肿胀与非晶化）的影响，揭示Ce含量对材料的结构参数、电子结构、溶解能及其抗辐照性能的影响，以期为锕系高放射性核废物陶瓷固化研究提供更加确凿可信的实验依据，本项目的研究具有重要的科学和现实意义。

中文关键词： 核材料；离子束辐照；辐照效应；损伤机理

英文摘要： The safe disposal of high-level nuclear waste(HLW) is a key issue in the development of nuclear energy, which needs to be solved, and represents one of the hot research topics over the world. Immobilization of HLW is a challenging task at present and must be archived for safely operating current and next generation nuclear reactors. In the proposal, element Ce will be used to simulate Pu and U ceramic immobilization because Ce is very similar to Pu and U. On the basis of preparation of Ce containing rare earth titanate pyrochlore ( CexA1-x ) 2Ti2O7 ( A=Y, Gd, Lu; x=0-1 ), Ne and Xe ions will be used to perform radiation experimentals. At the same time,the structure parameters, charge distribution and defect energy of the Ce containing pyrochlores will be determineed using first principles calculations based on the density functional theory with VASP code, which irradiation effects will be explored by molecular dynamics (MD method). The relationship between radiation effects (volume swelling effect and radiation amorphization dose) with Ce containing and rare earth ion in A site, as welll as the effects of the structure, charge distribution and the defect energy on radiation resistance of these materials will be revealed. It is a goal for this study to provide more conclusive experimental evidence for actinide high-level nuclear waste ceramic immobilization. The research of this project has important scientific and practical significance.

英文关键词： Nuclear material;Ion beam irradiation;Irradiation effects;Mechanism of damage