The coupled neutron transport calculation of Monte Carlo multi-group and continuous cross section

Abstract

It is well known that Monte Carlo neutron transport calculation based on the continuous cross section is with high precision, but the computing time is too long and memory consumption is large relative to the multi-group calculation. In contrast, the multi-group calculation is good both in terms of speed and memory relative the continuous calculation, but the short appears on S(α,β) and resonance energy region. For combining the advantages of these two models, we firstly develop the collision mechanism based on material. Then the coupled model is investigated based on the multi-group and continuous. The continuous model was employed to treat the thermal and resonance energy ranges, the multi-group model uses in the other energy ranges. Different energy ranges are coupled through the neutron scattering and fission contributions between each other. We chose the ITER 1-D sphere model for test example. This example contains a great amount of hydrogen, deep-subcritical and involves thermal scattering and resonance. The result of continuous model is as standard. The cases of criticality fission source and fixed source are considered. The comparison shows good agreement between coupled and continuous model. The speedup of coupled model increases about two times relative continuous model. The validity of coupled model has been proved by numerical simulation.