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A Channel-Network-Model for Radionuclide Transport in Fractured Rock-Testing Against Field Data

Published online by Cambridge University Press:  15 February 2011

Björn Gylling ,
Luis Moreno  and
Ivars Neretnieks
Björn Gylling
Affiliation:
Department of Chemical Engineering and Technology, Royal Institute of Technology, S-100 44 Stockholm, Sweden.
Luis Moreno
Affiliation:
Department of Chemical Engineering and Technology, Royal Institute of Technology, S-100 44 Stockholm, Sweden.
Ivars Neretnieks
Affiliation:
Department of Chemical Engineering and Technology, Royal Institute of Technology, S-100 44 Stockholm, Sweden.
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Abstract

A new model concept for describing flow and transport in fractured rock has been tested on some field tracer experiments. The flowing water in the rock is envisaged to take place in a three-dimensional network of channels with stochastic properties. For times of interest for deep geological repositories for nuclear waste it has been found that the volume of the channels, i.e. the flow porosity of the rock, has no practical influence on the Residence Time Distribution of the nuclides. It is totally dominated by the matrix diffusion effects. The specific Flow Wetted Surface, FWS, of the channels therefore needs to be known. A method to evaluate the FWS from hydraulic measurements in boreholes is presented.

Tracer tests at the Swedish ÄSPÖ rock laboratory have been predicted using this model and data obtained in the way outlined in the paper. The main tracer test was predicted reasonably well without using any adjustable parameters. Some other tracers also used were not detected in the tests as they were expected to be. We discuss some of the possible reasons for this in relation to geological observations made in the expected pathways for these tracers. The sensitivity of results to uncertainties in parameter values is also discussed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 353: Symposium – Scientific Basis for Nuclear Waste Management XVIII , 1994 , 395
Copyright
Copyright © Materials Research Society 1995

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References

REFERENCES

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