Sistema híbrido fusão-fissão baseado no Tokamak - análise neutrônica da inserção do diversor

Abstract

The Hybrid Fusion-Fission System based on Tokamak has a high potential for transmutation of actinides and fission products, which for the most part have a long half-life and high radiotoxicity. This system consists of a nuclear fusion reactor coupled to a subcritical fission blanket called the transmutation layer. In this work, starting from a model already developed in the Departamento de Engenharia Nuclear, the insertion of the Divertor component and its influence on the neutronic behavior of the transmutation layer was analyzed. The Divertor component is located along the bottom of the Plasma Chamber and has the main function of extracting the heat and ash generated as a product of the fusion reactions and other impurities in the plasma. It consists of two parts: the stainless-steel support structure and the plasma interface components. Two models with different geometric representations were analyzed to simulate the Divertor component, in order to assess whether the insertion of this component can affect the nêutron flux characteristics in the transmuting layer and, consequently, its transmutation capacity. The results obtained indicate that the systems simulated with the Divertor componente presented better performance both in the transmutation and in the conversion of the transmutation layer, in comparison to the system without this component. This is because the Divertor component allows greater spreading of the neutrons from the plasma source, considerably increasing the population of neutrons that arrive at the transmutation layer. The neutronic data were obtained by the code MCNP5 and the data on the variation of the fuel composition, activity and radiotoxicity during the burnup were obtained by ORIGEN2.1, which, using the code MONTEBURNUS, executes the first two codes connected.