Actors Notebook Nr 1 - Geological disposal: an unavoidable option for the system of sustainable management of radioactive wastes? Theme 1 - The role of Cigeo in the waste management system; Theme 2 - The control of risks specific to Cigeo

This issue addresses the issue of geological storage of radioactive wastes. It evokes the concerned wastes, and the warehousing and transmutation as additional rather than alternative solutions to disposal. It presents the Cigeo project which aims at an industrial implementation of a reversible geological disposal. It evokes the dialogue process associated with this project, and the associated risks during the exploitation phase and after disposal closure. The next part first addresses the role of Cigeo in the waste management arrangement. It more particularly presents the different types of wastes to be stored in Cigeo (waste inventory elaboration, brief opinion of the IRSN), addresses the issue of reversibility (law content, notions of parcel retrievability and of reversibility period, definition of reversibility), proposes an overview of warehousing installations (design and safety aspects, long duration warehousing), addresses the possibility of the separation/transmutation technology for long-life wastes (notions and techniques of separation and transmutation, consequences for the fuel cycle). The second part of this issue addresses the management of risks specific to Cigeo. It more particularly addresses the exploitation phase (key notions, risk of dissemination of radioactive materials, personnel exposure and fire hazard, risks related to other external aggressions), the safety of high-activity and medium-activity long-life waste parcels, the storage sealing (associated safety functions, expected properties, issue of performance demonstration), the notion of geological barrier (associated safety functions, geological characteristics and confinement properties of the geological environment, evolution of these properties). The issue finally proposes a set of sheets presenting current experiments and studies: diffusion experiments, study of natural tracers, the study of fractures with respect to radionuclide transport, seismic or electric methods of detection of natural discontinuities either from the surface or from underground works, sealing performance tests, study of the interaction between materials introduced into the storage (iron, concrete), control of gallery boring, crack initiation and behaviour with respect to humidity and air temperature in galleries