Numerical Researches of the Sodium-Void Reactivity Effect (SVR), Measured on the 'ZEBRA' Experiments

The results of calculations of sodium-void reactivity effect, measured on the 'ZEBRA' experiments for five different stages of sodium voiding are represented. The calculations were performed in 26-th group diffusion approximation, as well as using the Discrete Ordinates method (S4 - approximation, 26 groups) in X-Y-Z geometry within the framework of a program package 'REACTOR'. Good consistency of calculated and experimental values in four of five stages of voiding is received. The reasons of some discrepancies are analyzed and the ways of their overcoming are scheduled.