[en] Deep geological repositories of radioactive waste are designed and licensed based on a model of long-term safety which does not require the active presence of man. During the period of stepwise development of such repositories, reversibility of decisions and retrievability of the waste are widely thought to be beneficial. Reversibility and retrievability are not requirements for long-term safety. They are instead about implementing a process that responds to ethical and precautionary obligations without compromising safety. How are the concepts of reversibility and retrievability understood in the various nuclear countries? How do they appear in national waste management legislation, regulation and operational programmes, and how can they be implemented? The international project 'Reversibility and Retrievability in Geological Disposal of Radioactive Waste' (R and R) was conducted within the framework of the Nuclear Energy Agency 2007-2011. This project aimed at establishing a shared understanding of these concepts and of the related opportunities and limitations. The 'R and R' project of the OECD Nuclear Energy Agency (NEA) culminated in an International Conference and Dialogue on Reversibility and Retrievability in December 2010. The international members of the R and R project prepared the Conference and Dialogue in order to open the discussions to a larger audience. Objectives were to: - Allow as many points of view as possible to be expressed and to record them; - Discuss and better understand commonalities and differences; - Test and refine the findings of the draft NEA R and R project report; Refine the international R-scale, a tool for dialogue that has been developed within the framework of the NEA R and R project. The event was opened to any interested party; five relevant communities participated: Civil Society Stakeholders (representatives of local publics, Mayors and others); Implementers and RD and D; Regulators; Policy Makers; Social Scientists. These proceedings include the texts of 50 presentations and the 'International Retrievability Scale' - a tool to support dialogue with stakeholders and to help establish a common international framework