Lattice contraction and lattice deformation of UO2 and ThO2 doped with Gd2O3

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  • KUL - Katholieke Universiteit Leuven

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Abstract

"The lattice deformations in two doped fluorite systems, (U1-xGdx)O2.00 and (Th1‑xGdx)O2-x/2, have been reassessed by precise X-ray and electron diffraction investigations and the results were interpreted using the Bond Valence Sum (BVS) approach. For the (U1-xGdx)O2.00 system, the experimental findings and theoretical assessment confirm earlier work: the lattice keeps its fluorite structure with a unit cell parameter that contracts linearly with dopant concentration. The lattice contraction in the (Th1‑xGdx)O2-x/2 system has for the first time been analyzed up to the solubility limit. Similar as for (U1-xGdx)O2.00, the (Th1‑xGdx)O2-x/2 solid solution contracts linearly as a function of dopant concentration but additionally, it develops a superstructure which is closely related to the parent fluorite structure. An excess anion bixbyite trial model is proposed to describe this superstructure."

Details

Original languageEnglish
Pages (from-to)135-143
Number of pages9
JournalJournal of Nuclear Materials
Volume467
Issue number1
DOIs
Publication statusPublished - 14 Sep 2015

Keywords

  • Condensed matter, Uranium dioxide, Thorium dioxide, Gadolinium sesquioxide, Solid solutions, UO2-Gd2O3, ThO2-Gd2O3, X-ray diffraction, Electron diffraction, Diffuse scattering, Structure defects, Fluorite, Bixbyite, Bond Valence Sum

ID: 1128620