Strategies for decommissioning small nuclear reactors in Brazil

Abstract

The process of decommissioning nuclear reactors is a complex activity that involves various technical and administrative stages. Its main objective is to ensure the safety of the site, workers, the general public, and the environment during the execution of decommissioning activities, aiming for the release of the site from regulatory control. In the Brazilian context, it is essential to develop decommissioning strategies, taking into consideration the established technical and regulatory requirements, as well as following the guidelines of the Brazilian Nuclear Policy (BNP). Eight decommissioning strategies were proposed for small reactors, with different objectives and in different scenarios, encompassing 23 decommissioning approaches, divided into 6 groups: 1) decontamination and dismantling (DD); 2) radioactive waste (RW) management; 3) RW storage management; 4) human resources (HR) and knowledge management; 5) cost estimation; and 6) financial fund management. Additionally, 18 factors affecting the selection of these approaches were considered, taking into account particularities of the Brazilian context. A qualitative risk analysis was conducted using risk assessment techniques from the ABNT NBR ISO/IEC 31,010 standard, with a focus on the Multicriteria Decision Analysis (MCDA) technique. This qualitative analysis allowed for the evaluation of the approaches considering the current scenario and the future scenario, which includes possible changes in the BNP currently under discussion in the National Congress. The observations and results obtained in this study will be useful in guiding future efforts related to nuclear reactor decommissioning projects in Brazil. Based on the proposed strategies and considerations of safety, regulation, and governmental policies, it will be possible to plan and execute decommissioning activities more efficiently and safely.