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Synthesis and Characterization of Brannerite Compositions for MOX Residue Disposal

Published online by Cambridge University Press:  19 December 2016

D.J. Bailey ,
M.C. Stennett  and
N.C. Hyatt
D.J. Bailey*
Affiliation:
Immobilisation Science Laboratory, Department of Materials Science and Engineering, Univeristy of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom
M.C. Stennett
Affiliation:
Immobilisation Science Laboratory, Department of Materials Science and Engineering, Univeristy of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom
N.C. Hyatt
Affiliation:
Immobilisation Science Laboratory, Department of Materials Science and Engineering, Univeristy of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom
*
*(Email: dbailey2@shef.ac.uk)
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Abstract

Due to their high actinide content MOX residues require immobilization within a robust host matrix. Although it is possible to immobilize actinides in vitreous wasteforms; ceramic phases, such as brannerite (UTi2O6), are attractive due to their high waste loading capacity and relative insolubility. Brannerites Gd0.1U0.9Ti2O6, Ce0.1U0.9Ti2O6 and Gd0.1U0.81Ce0.09Ti2O6 were prepared using an oxide route. Charge compensation of trivalent cations was expected to occur via the oxidation of U (IV) to higher valence states (U (V) or U (VI)). Gd was added to act as a neutron absorber in the final Pu bearing wasteform and Ce was used as a structural surrogate for Pu. X-ray absorption spectroscopy showed that Ce (IV) was reduced to Ce (III) in all cases. X-ray powder diffraction of synthesized specimens found that the final phase assemblage was strongly affected by processing atmosphere (air or argon). Prototypical brannerite was formed in all compositions, secondary phases observed were found to vary according to processing atmosphere and stoichiometry. Microstructural analysis (SEM) of the sintered samples confirmed the results of the X-ray powder diffraction.

Keywords

Uceramicmicrostructure
Type
Articles
Information
MRS Advances , Volume 2 , Issue 10: Scientific Basis for Nuclear Waste Management XL , 2017 , pp. 557 - 562
Copyright
Copyright © Materials Research Society 2016 

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References

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