DIFFUSION COEFFICIENT OF RADIONUCLIDES IN CEMENT-BASED MATERIALS: INVESTIGATING THE EFFECT OF THE CHARGED SURFACES
Résumé
This work aims to provide new insights into the effect of charged surfaces in cement-based materials through a significant sum of diffusion and electro-diffusion experiments on various radionuclides acquired in the framework of EURAD/CORI and different Andra projects. All the measurements have been analysed with the reactive transfer model PhreeqC setting apart the diffusion and retention mechanisms. HTO appeared to be the most mobile species compared with anions and cations; in particular, no anionic or cationic exclusion/acceleration effects have been found in these experiments. A modelling exercise focusing on the behavior of anionic species, which are the main contributors to the dose, improves the understanding of their diffusion within pristine and degraded cement-based materials. The outcomes of this work will specifically reduce the uncertainties regarding the fate of 36Cl.