Use of Effective Diffusion Homogenization method with the Monte Carlo code for light water reactor

The use of Monte Carlo transport method with the Serpent code for generating unit cell cross sections of a light-water reactor is investigated. The geometry is a 3 × 3 array of cells, where homogenization is performed over the central cell, while the neighboring cells represent a kind of color-set scheme to model the radial leakage from the central cell. Instead of the default homogenization method of Serpent, the Effective Diffusion Homogenization method is applied externally, which conserves reaction rates, as well as the boundary partial currents of the central cell. The exercise serves to explore the potential of the Monte Carlo method for core design calculations and to validate and improve the existing computational scheme in which unit-cell calculations are based on the 1-D deterministic transport model in the WIMSD code. The cross sections by both methods are compared and applied to predict the hot-zero-power critical boron concentration and radial power distribution of the Krško NPP in comparison with measured values. The results confirm applicability of Monte Carlo transport calculations with EDH homogenization at the unit-cell level and warrant further extension to burnup and whole-assembly Monte Carlo modeling, at least for validation purposes due to present computational time constraints.