Equivalence treatment in homogenization via Monte Carlo method

• Multi-group constants generation via Monte Carlo methods.
• GET and SPH are used for equivalence in the Monte Carlo homogenization.
• The SPE method is developed to overcome the limitations of GET and SPH techniques.

The multi-group constants generated via continuous energy Monte Carlo method do not satisfy the equivalence between heterogeneous and homogeneous calculation. To meet the requirement of equivalence, the general equivalence theory (GET) and the superhomogenization method (SPH) are applied to the Monte Carlo based group constants. Both of the methods improved accuracy. Inheriting the essences of GET and SPH, the super equivalence method (SPE) is developed in this paper to overcome the limitations of the two conventional equivalence techniques. The three methods have been implemented into the Monte Carlo based homogenization code MCMC. Test calculations were carried out in a simplified PWR reactor core and the C5G7 MOX fuel benchmark. The study has shown that the equivalence treatment is necessary in Monte Carlo homogenization calculations and the SPE method can meet the requirement.