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Uranium (iv) Dioxide and Simfuel as Chemical Analogues of Nuclear Spent Fuel Matrix Dissolution. A Comparison of Dissolution Results in a Standard Naci/NaHCO3 Solution

Published online by Cambridge University Press:  15 February 2011

Jordi Bruno
Affiliation:
MBT Tecnologia Ambiental, 08290 Barcelona, Spain.
I. Casas
Affiliation:
Dept. Chem. Eng., Universitat Politècnica de Catalunya, 08028 Barcelona, Spain.
E. Cera
Affiliation:
MBT Tecnologia Ambiental, 08290 Barcelona, Spain.
J. de Pablo
Affiliation:
Dept. Chem. Eng., Universitat Politècnica de Catalunya, 08028 Barcelona, Spain.
J. GimÉnez
Affiliation:
Dept. Chem. Eng., Universitat Politècnica de Catalunya, 08028 Barcelona, Spain.
M. E. Torrero
Affiliation:
Dept. Chem. Eng., Universitat Politècnica de Catalunya, 08028 Barcelona, Spain.
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Abstract

We have carried out an experimental comparison study of the dissolution rates of unirradiated UO2 and SIMFUEL pellets and particles (100–300 μm) in a standard NaCI/NaHC03 solution, under oxidizing conditions. We have performed the experiments using batch and flow methodologies. Both methodologies gave similar results, indicating that the overall oxidation/dissolution process is the same in both cases. The results from the experiments indicate that under these conditions the dissolution process is both oxygen and bicarbonate promoted. The dissolution rates we obtained are: R=2.4 ± 0.8 mg U/m2 d for U02 and R= 0.17 ± 0.05 mg U/m2 d for SIMFUEL. The results of the experiments indicate that the dissolution rate under oxic conditions is clearly dependent on the number of U(VI) surface sites which for spent nuclear fuel is a function of the extent of radiolytic oxidation.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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References

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