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Modelling in-situ Matrix Diffusion at Palmottu Natural Analogue Study Site in SW Finland.

Published online by Cambridge University Press:  01 January 1992

Karl Rasilainen  and
Juhani Suksi
Karl Rasilainen
Affiliation:
Technical Research Centre of Finland, Nuclear Engineering Laboratory, P.O. Box 208, SF-02151 Espoo, Finland
Juhani Suksi
Affiliation:
University of Helsinki, Department of Radiochemistry, SF-00170 Helsinki, Finland
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Abstract

Radioactive disequilibria, between U-238, U-234, and Th-230, in crystalline rock adjacent to a fracture, indicates mass transfer of U and Th between water in the fracture and the rock. The matrix diffusion theory was used to interpret the observed profiles of mobilized nuclides around the natural fracture. The interpretation of the profiles was based on the use of uranium series disequilibrium code, URSE, and migration code FTRANS. The model system was characterized using all available site-specific data, and the system evolution was outlined using the geology of the Palmottu site. The simulated concentration profiles, as a function of depth from the fracture surface, indicate that measured profiles can be modelled by matrix diffusion, assuming realistic initial and boundary conditions and diffusion times of 300,000 years.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 294: Symposium V – Scientific Basis for Nuclear Waste Management XVI , 1992 , 489
Copyright
Copyright © Materials Research Society 1993

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References

REFERENCES

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