Feasibility Study on Oxide/Molten Salt-fueled CANDU Reactor with Two Regions Bundles

摘要

The heavy water moderated thermal neutron thorium reactor has a potential to makebreeding feasible since the neutron reproduction factor of ~(233)U in thermal energy range exceeds 2.0.This study examined the feasibility of thorium-thermal breeder reactor. The CANDU 6 was selectedas a reference reactor and the fuel bundle design was modified for improving neutron economy. Themodifications include "structural material of cladding tube and pressure pipe", "fuel bundle pitch"and "fuel bundle structure". Consideration was also made on not only the oxide fuel but also thefluoride molten salt fuel which is no need for fabrication process of solid fuel pellet. As for oxide fuelCANDU reactor adopted with those three modifications, the optimum ~(233)U enrichment which enablesachieving high burnup and fuel breeding was found to be around 2.3wt%. Consequently, thedischarged burnup was improved up to about 10GWd/Thm. The CANDU reactor with fluoride moltensalt fuel adopted with three modifications didn’t have breeding capability in this study. This is becauseparasitic neutron absorption of fluoride molten salt fuel is higher than oxide fuel. There is possibilityto design oxide breeding CANDU reactor.