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Dissolution of Technetium From Nuclear Waste Forms

Published online by Cambridge University Press:  25 February 2011

M. Yasser Khalil  and
William B. White
M. Yasser Khalil
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
William B. White
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
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Abstract

The immobilization of 99Tc in both ceramic and borosilicate glass waste forms and the mechanism of dissolution of technetium from these waste forms are complicated by the range of technetium valence states. Metallic Tc,ionic Tc4+ oxides, and volatile molecular species containing Tc7+ all occur within the stability field of water. Tc4+ will substitute readily for Ti4+ in titanatebased ceramics in such phases as perovskite (CaTiO3) and spinel (Mg2TiO4). Tc4+ can be homogeneously distributed in borosilicate glass by re-melting the glass under closed system conditions to prevent the re-oxidation of technetium. The dissolution of technetium from both glass and ceramic waste forms follow similar kinetic behavior although the dissolution rate from the titanate is two orders of magnitude lower. Dissolution under highly reducing conditions is too slow to measure on the time scale of the experiments.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 26: Symposium D – Scientific Basis for Nuclear Waste Management VII , 1983 , 655
Copyright
Copyright © Materials Research Society 1984

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References

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