Summary

Radioactive waste must be managed and disposed off in ways that ensure the protection of people and the environment, now and in the future. In this sense, the long term prediction of disturbances in the surrounding rock mass induced by the construction and the operation of a waste repository is essential to assure a maximal protection of the environment and the people for both current and future generations against the soil contamination and a radionuclide release. Indeed, the evaluation of the evolution of the Excavated Damaged Zone (EDZ) with time is particularly important since its presence may result in changes to the transport characteristics of the rock mass adjacent to underground openings. The SELFRAC project aims to properly characterise the EDZ and its evolution with time. The main objective of the project is to understand and to quantify these processes and to assess their impact on the performance of radioactive waste geological repositories. Two different potential geological formations for deep radioactive waste repositories are studied: the Opalinus Clay of Mont Terri (Switzerland) and the Boom Clay (HADES, Belgium). First results are clearly demonstrating the sealing capacities of both clays leading to the decrease of the hydraulic transmissivity along the fractures