The potential for removing gallium from Ga-doped CeO2-x by thermal means wa
s studied for the purpose of assessing gallium removal from PuO2-x. The lat
ter is of interest to those considering the storage or use of weapon-grade
Pu, for example as a mixed oxide fuel component. Experiments were done by v
arying temperature, gas composition, exposure time, sample size, particle s
ize, and gas flow rate. The kinetics of gallium removal were assessed throu
gh measurements of weight change, scanning electron microscopy, and chemica
l analyses. Results suggest that the gallium level can be reduced significa
ntly by thermal treatments in Ar-6% H-2. Gallium species segregate to grain
boundaries because of the low solubility of Ga2O3 in CeO2. The kinetics an
d microstructural observations suggest that both gaseous and solid-state di
ffusion of gallium species are important for the removal of gallium. (C) 20
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