Contribution of the results of the CEBAMA project to decrease uncertainties in the Safety Case and Performance Assessment of radioactive waste repositories

International audienceCement-based materials are key materials used in repositories of low, intermediate and high-level radioactivewaste in any host-rock concept. These materials are used for waste conditioning, liners, seals as well as structuralcomponents. The CEBAMA (CEment-BAsed MAterials, properties, evolution, barrier functions) project(2015–2019) has been an initiative granted by the European Commission under the Horizon 2020 Research andTraining Programme of the European Atomic Energy Community (EURATOM), focused on the study ofcementitious materials. The project has addressed key issues of relevance for long-term safety and key scientificquestions related to the use of cement-based materials in nuclear waste disposal applications. This publicationpresents the advances resulting from the research undertaken in the CEBAMA project, with special emphasis ontheir contribution to decrease uncertainties in the Safety Case and the Performance Assessment of radioactivewaste repositories. The analysis is presented in three different axes, in coincidence with the lines of research ofthe project: degradation of cement-based materials and its impact on cement/clay interfaces; retention of safetyrelevant radionuclides and toxicants on cement-based materials and modelling advances in cementitious relatedsystems. The research investigations have provided important new insights on process understanding and modeldevelopments which have significantly decreased the level of uncertaint