The effect of electron-ion coupling on radiation damage simulations of a pyrochlore waste form.

Ismail, Ahmed E. (Sandia National Laboratories, Carlsbad, NM) ; Foiles, Stephen Martin ; Greathouse, Jeffery A. ; Crozier, Paul Stewart

关键词: AR FACILITIES;    ATOMS;    DEFECTS;    DIFFUSION EQUATIONS;    ELECTRON-ION COUPLING;    FRICTION;    GADOLINIUM;    KNOCK-ON;    PYROCHLORE;    RADIATIONS;    SPATIAL DISTRIBUTION;    WASTE FORMS Gadolinium.;    Ion flow dynamics.;   

DOI  :  10.2172/974414
RP-ID  :  SAND2009-6892
PID  :  OSTI ID: 974414
Others  :  TRN: US1002716

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

We have performed molecular dynamics simulations of cascade damage in the gadolinium pyrochlore Gd{sub 2}Zr{sub 2}O{sub 7}, comparing results obtained from traditional methodologies that ignore the effect of electron-ion interactions with a 'two-temperature model' in which the electronic subsystem is modeled using a diffusion equation to determine the electronic temperature. We find that the electron-ion interaction friction coefficient {gamma}{sub p} is a significant parameter in determining the behavior of the system following the formation of the primary knock-on atom (here, a U{sup 3+} ion). The mean final U{sup 3+} displacement and the number of defect atoms formed is shown to decrease uniformly with increasing {gamma}{sub p}; however, other properties, such as the final equilibrium temperature and the oxygen-oxygen radial distribution function show a more complicated dependence on {gamma}{sub p}.