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The Retention of Redox Sensitive Waste Elements in Compacted Bentonite

Published online by Cambridge University Press:  25 February 2011

B. Torstenfelt  and
B. Allard
B. Torstenfelt
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 diffusion of technetium, iodine, uranium and neptunium in compacted bentonite has been studied. The possible reduction of the transport rate of these elements (i.e. redoxsensitive elements) by mixing the clay with metallic iron (for technetium, uranium and neptunium) or by adding a chemisorbent (for iodine) to the clay is reported. Technetium has an apparent diffusivity about 5 times higher in the heptavalent state (TcO4−) than in the tetravalent state (TcO(OH)2 or TcO2), uranium and neptunium in their higher oxidation state (VI and V) have apparent diffusivities about 6 and 50 times higher, respectively, than in the tetravalent state. Iodine, as I− (or 103−), has a transport rate more than one order of magnitude lower than TcO4−.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 26: Symposium D – Scientific Basis for Nuclear Waste Management VII , 1983 , 789
Copyright
Copyright © Materials Research Society 1984

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References

REFERENCES

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