Community Research and Development Information Service - CORDIS

Abstract

The Boom clay layer has been selected as a potential host formation for the disposal of high level radioactive waste in Belgium. The safety of the nuclear waste repository will rely mainly upon the ability of the geological barrier to retain and to retard the radionuclides released from the waste packages. The objective of the migration project is to understand the basic phenomena governing the mobility of the radionuclides in the Boom clay, to determine their migration parameters and to develop the models (MICOF) needed by the performance assessment studies to extrapolate their transport on a geological time scale.
The migration of radionuclides in the Boom clay is studied by means of laboratory diffusion and percolation experiments on small clay cores, and by large scale in situ injection experiments with non-sorbed tracers. Up to now, a good agreement exists between the model calculations and the experimental measurements exists between the model calculations and the experimental measurements obtained with the tritiated water injection. The model and the diffusion parameter values derived from laboratory scale experiments remain valid under in situ conditions at a metric scale.
Because of the very low hydraulic conductivity of the Boom clay, and the absence of water active fractures in a plastic clay formation, the migration of radionuclides is mainly controlled by molecular diffusion. The results of the laboratory migration experiments show that the key parameters for the migration are eta R and the apparent diffusion constant D. The advection plays only a secondary role at the (time and space) scale of the migration experiments performed in this work. .

Additional information

Authors: DE CANNIERE P, SCK/CEN, Mol (BE);MOORS H, SCK/CEN, Mol (BE);LOLIVIER P, SCK/CEN, Mol (BE);PUT M, SCK/CEN, Mol (BE);DE PRETER P, NIRAS/ONDRAF, Bruxelles (BE)
Bibliographic Reference: EUR 16927 EN (1996) 51pp., FS, ECU 8.50
Availability: Available from the (2)
ISBN: ISBN 92-827-7463-5
Record Number: 199611205 / Last updated on: 1996-11-11
Category: PUBLICATION
Original language: en
Available languages: en