Study of few-group constant generation methods with Serpent Monte Carlo code based on JOYO MK-I fast reactor data

Szogradi, M.*; Nagaya, Yasunobu  

A new nodal diffusion solver Ants has been developed at VTT for the development of Generation IV reactor concepts. The two-step approach where group constants are generated via Monte Carlo (MC) methods is used for the reactor core analysis. To validate this approach, the JOYO MK-I core published in the International Handbook of Evaluated Reactor Physics Benchmark Experiments was analyzed. The Serpent Monte Carlo code was used to obtain group constants of the JOYO MK-I core. The Serpent few-group cross sections were then used as input data for Ants. Calculations were also carried out with Serpent and the MVP Monte Carlo code for a full-core 3D model to assess the general performance of the code comparing neutron spectrums and power spatial distributions. Results obtained with the 3D Ants JOYO model were compared with the MC results as the first assessment of the nodal diffusion solver with fast system.