Effect of CANFLEX Bundle Design on CANDU-6 Reactor Safety

Abstract

A recently developed advanced CANDU fuel bundle, CANFLEX has two major design improvements over the 37-element standard bundle: bundle ring power flattening and CHF enhancement. Effect of each of the two design changes of CANFLEX bundle on CANDU-6 reactor safety has been assessed for the two representative accident scenarios, 30% RIH break (large break LOCA) and total loss of class IV power to all PHT pumps (non-LOCA) using CATHENA and SOPHT simulations. The bundle ring power flattening increases the safety margin for both large break LOCA and non-LOCA, but the 10% CHF enhancement increases the safety margin for non-LOCA only.