Resumen
Several nuclear plants were built worldwide and will need to be shut down in a specific time for being near their recommended lifespan which is about 40 years. For this reason, the aims of the International Atomic Energy Agency (IAEA) is to guide and recommend guidelines for the implementation of decommissioning activities for nuclear power plants and research reactors throuigh publishing. The agency gives special attention to the countries which do not have a legal regulatory framework directed to decommissioning activities.Brazil has only regulation on decommissioning whosefocus is thye nucleoelectric power plants.The Nuclear and and Energy Research Institute (IPEN- Instituto de Pesquisas Energéticas e Nucleares) has two research reactors and one of them is the IPEN/MB-01 Reactor.The aim of this work is to present the current stage of the preliminary decommissioning plan of the reactor, highlighting the main proposed procedures. These invlove the strategy selection, the project management, the activities whuch will be carried out as well as the waste management and disposal as a result of decommissioning the facility component where the reactor core is located,the critical assembly. The preparation of these procedures and the preliminary plan as a whole are based on the technical documentation (SAR-Safety Analysis Report), on National Nuclear Energy Commission (CNEN) existing standards and on recommendations on IAEA publications. The preliminary decommissioning plan is to present the actions and steps required as well as the satrtegies to be adopted for the shutdown of the facility of the technical and administrative framework in order to safety, health workers and the generalpublic, minimizing environmental impacts. The contribution of this paper aims to even meet a regulatory requirement of CNEN when shutdown the facility and also as a reference in developing of other decommissioning plans in others national facilities.