An essential element in the research field of disposal is the long-term safety analysis in the safety case, i.e., the process of systematically analyzing the hazards associated with the facility and the ability of the site and design to ensure the required safety functions as well as to meet the technical requirements. The work envisioned in EVIDENT will add to the body of knowledge on the behavior and long-term barrier function of the bentonite buffer under natural conditions in the host rock crystalline. The close interaction with the Colloid Formation and Migration (CFM, coordinated by NAGRA) project conducted at the Grimsel Test Site (GTS, Switzerland) also ensures the essential international cooperation mentioned in the project funding program. The working topics are based on the CFM project objectives agreed with the CFM partners and are directly linked to ongoing in-situ experiments at GTS.The goal of the project is to increase the mechanistic understanding of the processes critical to the integrity of the geotechnical barrier under nearnatural, repository-relevant conditions in fractured granite systems and to provide robust predictive modeling of the bentonite-based geotechnical barrier and colloidborne radionuclide transport.