Charge compensation mechanisms in U1-xGdxO2 and Th1-xGdxO2-x/2 studied by X-ray Absorption Spectroscopy

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  • Aalto University
  • Soleil Synchrotron

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The charge compensation mechanisms in U1-xGdxO2 and Th1-xGdxO2-x/2 have been systematically studied using X-ray Absorption Spectroscopy (XAS) upon gradually increasing the Gd content. Our XAS results for a series of technologically relevant Gd contents in U1-xGdxO2 clearly demonstrate that upon increasing the Gd content U5+ is formed inducing slight increase in the U coordination number and contraction for the U-O distances while the Gd local environment remains virtually unchanged. For the Th1-xGdxO2-x/2 larger Gd fractions were applied (x ¼ 0.10 to 0.34). Nonetheless, both Gd and Th local environments show changes upon increasing the Gd content; the average Gd-O and Th-O distances decrease gradually and the Gd and Th coordination numbers follow the expected trend considering the O vacancy formation to obtain charge neutrality.


Original languageEnglish
Pages (from-to)9-21
JournalJournal of Nuclear Materials
Publication statusPublished - 29 Mar 2017


  • UO2, Gd, Charge compensation, XANES, EXAFS

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