UO(2 ± x) 中裂变产物的热力学

Thermodynamics of fission products in UO(2 ± x).

作者信息

Nerikar P V, Liu X-Y, Uberuaga B P, Stanek C R, Phillpot S R, Sinnott S B

机构信息

Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA. Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.

出版信息

J Phys Condens Matter. 2009 Oct 28;21(43):435602. doi: 10.1088/0953-8984/21/43/435602. Epub 2009 Oct 8.

DOI:10.1088/0953-8984/21/43/435602

PMID:21832440

Abstract

The stabilities of selected fission products-Xe, Cs, and Sr-are investigated as a function of non-stoichiometry x in UO(2 ± x). In particular, density functional theory (DFT) is used to calculate the incorporation and solution energies of these fission products at the anion and cation vacancy sites, at the divacancy, and at the bound Schottky defect. In order to reproduce the correct insulating state of UO(2), the DFT calculations are performed using spin polarization and with the Hubbard U term. In general, higher charge defects are more soluble in the fuel matrix and the solubility of fission products increases as the hyperstoichiometry increases. The solubility of fission product oxides is also explored. Cs(2)O is observed as a second stable phase and SrO is found to be soluble in the UO(2) matrix for all stoichiometries. These observations mirror experimentally observed phenomena.

摘要

研究了选定裂变产物——氙、铯和锶——在UO(2 ± x)中作为非化学计量比x的函数的稳定性。特别地，利用密度泛函理论（DFT）计算这些裂变产物在阴离子和阳离子空位、双空位以及束缚肖特基缺陷处的掺入能和溶解能。为了再现UO(2)的正确绝缘状态，使用自旋极化和哈伯德U项进行DFT计算。一般来说，电荷更高的缺陷在燃料基体中更易溶，并且随着超化学计量比增加，裂变产物的溶解度增大。还探讨了裂变产物氧化物的溶解度。观察到Cs(2)O为第二稳定相，并且发现对于所有化学计量比，SrO可溶于UO(2)基体。这些观察结果反映了实验观察到的现象。