A DRAGON-MCNP Comparison of Void Reactivity Calculations

Abstract

The determination of the reactivity coefficients associated with coolant voidingin a CANDU reactor is a subject which has attracted a large amount of interest in the last fewyears both from the theoretical and experimental point of view. One expects that deterministiccodes such as DRAGON and WIMS-AECL or the MCNP4 Monte Carlo code should be ableto adequately simulate the cell behaviour upon coolant voiding. However, the absence ofan experimental database at equilibrium and discharge burnups has not permitted the fullvalidation of any of these lattice codes, although a partial validation through comparison oftwo different computer codes has been considered. Here we present a comparison betweenDRAGON and MCNP4 of the void reactivity evaluation for fresh fuel.