Real time multi-temperature cross sections generation method in superMC for multi physics simulation of nuclear reactors

In this work, real time multi-temperature cross sections generation method in Monte Carlo simulations has been developed with special consideration to the features of wide energy regions of incident neutron, i.e. resolved resonance energy region, thermal energy region and unresolved resonance energy region. The technique has been implemented in SuperMC (Multi-functional Calculation Program for Nuclear Design and Safety Evaluation). Optimal double-exponential (De) method was proposed and adopted for resolved resonance region to improve efficiency of cross section generation, while keeping the precise cross section data. In accordance with the features of thermal scattering nuclear data, i. e. S(α,β) data at different temperature intervals, the Lagrange interpolation with Neville algorithm for generation of thermal scattering data is adopted. By these means, high generation efficiency and data accuracy was obtained. In this case of the unresolved resonance energy region, where the data is in a form of probability table (covering different temperature intervals), piecewise interpolation cross section generation method is proposed and adopted. Bn-600 benchmark was used to verify the correctness and validity of the developed real time multi-temperature cross sections generation method. The calculation results revealed that the proposed method can generate neutron cross section at the desired temperature with high efficiency and accuracy. It showed the capability of the developed method for applications in reactor multi-physical coupling simulations. (Author)