Neutronic Evaluation of a MHR System to Transmutation of Minor Actinides

The goal is to simulate the modular helium reactor (MHR) core to analyze the neutronic parameters behavior due the insertion of Pu isotopes and minor actinides (MAs) using shuffling scheme without compromising the safety parameters. Initially the core is filled with driver fuel (DF). After the burn-up, these fuels are then reprocessed and used to produce the transmutation fuel (TF). Some cycles after, the core is filled with DF and TF fuels. DF fuel is composed of Pu and Np while TF fuel is a mixture of Pu and MAs. The shuffling scheme was evaluated after each cycle. It was verified that neutronic parameters and isotopic composition reach equilibrium when this scheme is used. The WIMS code was used to perform the simulations and the following neutronic parameters were evaluated: infinite multiplication factor, spectrum hardening, and reactivity temperature coefficients.