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Actinide Migration in Granite Fractures: Comparison between In-Situ and Laboratory Results

Published online by Cambridge University Press:  11 February 2011

Bernhard Kienzler ,
Jürgen Römer ,
Peter Vejmelka ,
Mats Jansson ,
Trygve E. Eriksen  and
Kastriot Spahiu
Bernhard Kienzler
Affiliation:
Institut für Nukleare Entsorgung, Forschungszentrum Karlsruhe, D-76021 Karlsruhe, GERMANY
Jürgen Römer
Affiliation:
Institut für Nukleare Entsorgung, Forschungszentrum Karlsruhe, D-76021 Karlsruhe, GERMANY
Peter Vejmelka
Affiliation:
Institut für Nukleare Entsorgung, Forschungszentrum Karlsruhe, D-76021 Karlsruhe, GERMANY
Mats Jansson
Affiliation:
Dept. of Nuclear Chemistry, Royal Institute of Technology, SE-100 44 Stockholm, SWEDEN
Trygve E. Eriksen
Affiliation:
Dept. of Nuclear Chemistry, Royal Institute of Technology, SE-100 44 Stockholm, SWEDEN
Kastriot Spahiu
Affiliation:
Svensk Kärnbränslehantering AB (SKB), SE-102 40 Stockholm, SWEDEN
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Abstract

Results of migration experiments with fractured drill cores performed in laboratory and in the CHEMLAB 2 probe under in-situ conditions at Äspö HRL are presented. Drill cores for both experiments are prepared by the same method and provide similar hydraulic properties. As tracers, actinides Am(III), Pu(IV) and Np(V) are applied. Breakthrough of Np is found to be unre-tarded in comparison to inert HTO tracer. Recovery of Np amounts to less than 40%. Am and Pu are not eluted from the cores. Lower limits of the retardation factor of 135 are calculated for both Am and Pu. Post mortem investigations of the fractured cores are performed by cutting perpendicular to the cylinder axis and subsequent chemical and radiochemical analysis of abraded material and slices. Imaging of the slices reveals the geometry of the flow path. α-radiography of the slices shows similar distribution patterns of Np and Am. It is shown by TTA extraction that Np bound onto the slices is in the tetravalent state. Hence, Np(V) undergoes reduction during migration. Retention of Am and Np is attributed to different processes.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 757: Symposium II – Scientific Basis for Nuclear Waste Management XXVI , 2002 , II11.2
Copyright
Copyright © Materials Research Society 2003

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References

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