Advances in geochemical research for the underground disposal of high-level, long-lived radioactive waste in a clay formation

One of the options for the long-term confinement of high-level, long-lived radioactive waste is the disposal in deep geological formations. In France, this option is particularly studied in a 155-Ma-old Jurassic clay formation located in the eastern part of the Paris Basin. Fifteen years of research and the construction of an underground research laboratory have provided a large set of data that allows the feasibility of the geological disposal to be evaluated from a scientific standpoint. Geochemical aspects of this research are of major importance because they provide essential information on both the characteristics of the geological medium and the long-term behaviour of the waste and the engineered system.