Effects of an alkaline plume on the Boom Clay as a potential host formation for geological disposal of radioactive waste. First full draft - v1.0

This report presents the results of a detailed study on the possible magnitude of an alkaline plume originated from a cement based repository on the Boom Clay as a reference host rock. Literature review, in-house experiments, and geochemical coupled numerical modelling are performed to provide information about mechanisms of alkaline plume clay interactions, geochemical and transport parameters, and detailed numerical simulations on the extent of the perturbation. The results of the study suggest that an alkaline plume perturbation to Boom Clay is expected to be limited within 1 to 3 meters of the Boom Clay from the repository boundary. This implies that the alkaline plume is not a critical issue in the safety assessment for the Boom Clay as a host rock for radioactive waste disposal.