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Migration Experiments in Compacted Ca-Bentonite

Published online by Cambridge University Press:  10 February 2011

M. García-Gutiérrez ,
T. Missana ,
J. Molinero ,
A. Yllera  and
M. Mingarro
M. García-Gutiérrez
Affiliation:
CIEMAT, Departamento de Impacto Ambiental de la Energía, Av. Complutense 22, 28040 Madrid (Spain ).
T. Missana
Affiliation:
CIEMAT, Departamento de Impacto Ambiental de la Energía, Av. Complutense 22, 28040 Madrid (Spain ).
J. Molinero
Affiliation:
E.T.S. Ingenieros de Caminos, Universidad de La Coruña (Spain).
A. Yllera
Affiliation:
CIEMAT, Departamento de Impacto Ambiental de la Energía, Av. Complutense 22, 28040 Madrid (Spain ).
M. Mingarro
Affiliation:
CIEMAT, Departamento de Impacto Ambiental de la Energía, Av. Complutense 22, 28040 Madrid (Spain ).
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Abstract

Migration experiments were carried out in compacted Ca-bentonite as a complement of the FEBEX project large scale tests.

Through diffusion and permeation experiments with tritiated water were used to perform a deep characterisation of the clay diffusion parameters (diffusion coefficient, effective porosity and permeability ). In through diffusion experiments, a variation of tracer concentration in both reservoirs was allowed. Since in these experimental conditions an analytical solution of the diffusion problem does not exist, an analytical approximation was used and the results compared with a numerical model which takes into account the presence of the sintered steel filters confining the clay plug.

The migration behaviour of Se in this compacted bentonite has been studied and the retardatioci factor obtained. The calculated Kd is at least one order of magnitude lower than the one obtained by means of batch sorption experiments due to a lower availability of sorption sites when increasing the compaction degree.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 556: Symposium QQ – Scientific Basis for Nuclear Waste Management XXII , 1999 , 695
Copyright
Copyright © Materials Research Society 1999

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References

REFERENCES

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