The Planning Act of 28 June 2006 prescribed that a reversible repository in a deep geological formation be chosen as the reference solution for the long-term management of high-level and intermediate-level long-lived radioactive waste. It also entrusted the responsibility of further studies and investigations on the siting and design of the new repository upon the French Radioactive Waste Management Agency ( Agence nationale pour la gestion des de´chets radioactifs – Andra), in order for the review of the creation-licence application to start in 2015 and, subject to its approval, the commissioning of the new repository in 2025. In late 2009, Andra submitted to the French government proposals concerning the implementation and the design of Cige´o ( Centre industriel de stockage ge´ologique ). A significant step of the project was completed with the delineation of an interest zone for the construction of the repositor’s underground facilities in 2010. This year, Andra has launched a new dialogue phase with local actors in order to clarify the implementation scenarios on the surface. The selected site will be validated after the public debate that is now scheduled for the first half of 2013. This debate will be organized by the National Public Debate Committee (Commission nationale du de´bat public ). In parallel, the State is leading the preparation of an territorial development scheme, which will be presented during the public debate. The 2009 milestone also constitutes a new step in the progressive design process of the repository. After the 1998, 2001 and 2005 iterations, which focused mainly on the long-term safety of the repository, the Dossier 2009 highlighted its operational safety, with due account of the non-typical characteristics of an underground nuclear facility. It incorporates the first results of the repository-optimisation studies, which started in 2006 and will continue in the future. The reversibility options for the repository constitute proposals in terms of added flexibility in repository management and in package-recovery levels. They orient the design of the repository in order to promote those reversibility components. They contribute to the dialogue with stakeholders in the preparation of the public debate and of the future act on the reversibility conditions of the repository. The development of the repository shall be achieved over a long period, around the century. Hence, the designer will acquire additional knowledge at every new development of the project, notably during Phase 1, which he may reuse during the following phase, in order, for instance, to optimise the project. This process is part of the approach proposed by Andra in 2009 pursuant to the reversibility principle.