In a recent study, researchers from the Brazilian Nuclear Energy Commission (CNEN) and the Brazilian Center for Research in Energy and Materials (CNPEM) have investigated neutron transport within the reflector tank of the upcoming Brazilian Multipurpose Reactor (RMB). The team, led by Luiz Paulo de Oliveira and including Alexandre Pinho dos Santos Souza, Carlos Gabriel da Silva Santos, Iberê Souza Ribeiro Júnior, Barbara Perez Gonçalves Silva, Marco Antonio Stanojev Pereira, and Frederico Antonio Genezini, utilized the stochastic Monte Carlo method to model and understand the behavior of neutrons in this advanced nuclear reactor design.
The RMB is a next-generation multipurpose reactor designed for various applications, including the production of radioisotopes, material irradiation, and the generation of neutron beams for scientific research. One of the key factors in the performance of such reactors is the core power density, which is directly related to the neutron flux produced during fission reactions. To optimize the RMB’s design for its intended purposes, the researchers focused on studying the transport and moderation of neutrons within the reactor’s reflector tank.
The study revealed that the neutron moderation process in the reflector tank follows Maxwellian distributions, with temperatures ranging from 331.5 K in the core to 266.8 K in the peripheral regions. The researchers found that epithermal neutrons predominate (52%) in the reactor core, followed by thermal (29%) and fast (19%) neutrons. Notably, the moderation process is highly effective, with 100% of the neutrons falling within the thermal spectrum near the reflector tank wall. This finding is crucial for the efficient operation of the reactor and its various applications.
The research also highlighted another significant effect of neutron moderation: a shift in the peak wavelength from 1.07 Å to 1.19 Å. This shift was observed both within the reflector tank and along the tube supplying a neutron beam to the RMB imaging instrument, where the peak wavelength increased from 1.18 Å to 1.21 Å. Understanding these shifts is essential for optimizing the reactor’s performance and ensuring accurate scientific measurements.
The practical applications of this research for the energy sector are substantial. By gaining a deeper understanding of neutron transport and moderation, engineers and scientists can design more efficient and safer nuclear reactors. The insights provided by this study will be instrumental in the development of the RMB and other advanced nuclear reactors, ultimately contributing to the production of radioisotopes for medical and industrial use, material irradiation for research and development, and the generation of neutron beams for scientific investigations.
This research was published in the journal Nuclear Engineering and Design, providing a valuable contribution to the field of nuclear energy and reactor design. The findings will undoubtedly support the ongoing efforts to advance nuclear technology and expand its applications in various industries.
This article is based on research available at arXiv.