Experimental evaluation of a retention model for major groundwater elements on the Tournemire argillite

Titre du congrès :Clays in natural and engineered barriers for radioactive waste confinement Ville du congrès :Lille Date du congrès :17/09/2007

This work deals with the behaviour of Tournemire argillite towards major elements. Rock samples come from the IRSN Tournemire experimental facility, located in Aveyron, Southern France. Their "intrinsic" ion-exchange properties, i.e. the concentrations of the different types of adsorption sites and the associated selectivity coefficients for H, Na, K, Ca and Mg were previously determined (Jacquier et al., 2004). This set of data constitutes a retention model which enables to describe the behaviour of major cations and H+ during water-rock interaction. The objective of the present study is to estimate the robustness of this model by comparing experimental data derived from several types of leaching experiments carried out on Tournemire samples with the corresponding calculated data.