In France, the problem of radioactive waste has been subjected to different solutions. In 1979, the storage of radioactive waste was entrusted to a specialized operator, the National Agency for Radioactive Waste Management (Andra). Yet, through the course of its history, the Agency has faced many difficulties to implement its projects, which often came under strong public criticism. Still today, while its project of geological disposal is about to move into its industrial phase, the Andra is still widely criticized and serves as a crystallization point for power relationships in the nuclear sector. In order to retrace the evolution of French radioactive waste management since the 1950s, the archival and ethnographical study of the Andra’s organizational work provides an insider perspective on how its agents have defined problems, as well as conceived and implemented solutions. Indeed, through this strategic and political work, they have frequently transformed the Agency to fit the progress of its projects. From an industrial subsidiary of the French Atomic Energy Commission (CEA), the Agency was transformed into a finalized research agency, then again into an industrial operator in order to undertake to construction the geological disposal site. Through to these changes, actors have been able to revived criticized projects, without necessarily modifying their contents. In fact, it is not stability but organizational and institutional flexibility, which can account for the preservation of these controversial solutions. Lastly, the problem of radioactive waste crystallizes a multiplicity of temporal logics. The analysis of this work of temporalisation, which can be seen as a particular kind of organization, questions the articulation between change and permanency of public action. As such, this study sheds light on the relation between dynamics of problem definition, the construction of irreversible technical solutions, and organizational and temporal work.