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The Oxidative Dissolution Mechanism of Uranium Dioxide. The Effect of pH and Oxygen Partial Pressure

Published online by Cambridge University Press:  01 February 2011

Joan de Pablo ,
Ignasi Casas ,
Javier Giménez ,
Frederic Clarens ,
Lara Duro  and
Jordi Bruno
Joan de Pablo
Affiliation:
Department of Chemical Engineering, Universitat Politècnica de Catalunya, ETSEIB, Diagonal, 647 H-4, 08028, Barcelona, Spain.
Ignasi Casas
Affiliation:
Department of Chemical Engineering, Universitat Politècnica de Catalunya, ETSEIB, Diagonal, 647 H-4, 08028, Barcelona, Spain.
Javier Giménez
Affiliation:
Department of Chemical Engineering, Universitat Politècnica de Catalunya, ETSEIB, Diagonal, 647 H-4, 08028, Barcelona, Spain.
Frederic Clarens
Affiliation:
Department of Chemical Engineering, Universitat Politècnica de Catalunya, ETSEIB, Diagonal, 647 H-4, 08028, Barcelona, Spain.
Lara Duro
Affiliation:
ENVIROS Spain, Avda. Rubí 29–31, 08197 Valldoreix, Spain.
Jordi Bruno
Affiliation:
ENVIROS Spain, Avda. Rubí 29–31, 08197 Valldoreix, Spain.
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Abstract

The dissolution of the unirradiated uranium dioxide, UO2, is largely affected by chemical variables like pe, pH and carbonate concentration in solution. In a previous paper [1], we studied the kinetics of the dissolution of UO2 as a function of pH and oxygen partial pressure and the experimental dissolution rates obtained showed a fractional dependence on both parameters. These fractional orders indicate a dissolution occurring via a surface mediated mechanism.

In this work we have developed a mechanism accounting for the oxidative dissolution of UO2, which depends on the oxygen concentration in solution and on the pH and a general rate equation has been deduced. This mechanism has been used to explain the results obtained by different authors and to explain and predict the dissolution of the spent nuclear fuel matrix.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 807: Symposium Scientific Basis for Nuclear Waste Management XXVII , 2003 , 83
Copyright
Copyright © Materials Research Society 2004

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References

REFERENCES

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