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Generation and Transport Properties of Colloidal Tri-And Tetravalent Actinide Species in Geologic Environments

Published online by Cambridge University Press:  25 February 2011

U. Olofsson
Affiliation:
Department of Nuclear Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden.
M. Bengtsson
Affiliation:
Department of Nuclear Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden.
B. Allard
Affiliation:
Department of Nuclear Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden.
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Abstract

The formation of colloidal particle fractions of triand tetravalent actinides (Am(III), Th(IV), Pu) has been studied in aqueous solutions under various conditions. (Variations of nuclide concentration 10-7-10-11 M; pH 3-12; salt medium 0.01-1.0 M NaCl04; storage time 6 h-6 months; temperature 5°C, 25°C, 70°C). A large fraction of the nuclides is sorbed on the vessel walls, but there is also a formation of centrifugable particles. For americium this fraction has two maxima, at pH 5-8 and at pH above 12. For thorium and plutonium this fraction is very small except at pH about 12. In the pH-range 7-9, which is expected in underground waste repositories, the particle fractions do not seem to be highly mobile. Plutonium behaves very similar to thorium in all studied systems, so it is probably tetravalent to a large extent.

Type
Research Article
Copyright
Copyright © Materials Research Society 1984

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References

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