Westinghouse Accident Tolerant Fuel and Its Benefits for CANDU Reactors

Abstract

As part of the Accident Tolerant Fuel (ATF) program, Westinghouse is commercializing two unique accident tolerant or fault tolerant fuels, silicon carbide (SiC) cladding with uranium silicide (U₃Si₂) fuel and chromium (Cr) coated zirconium (Zr) alloy cladding withU₃Si₂ fuel. The use of U3Si2 increases the uranium density by 17% giving an effective enrichment of 0.84% Uranium-235 (U-235) for natural uranium as compared to UO₂. The higher thermal conductivity of the U₃Si₂ also provides a very high tolerance for transients while operating at higher linear heat generation rates than is possible for UO₂. SiC cladding would provide a 25% lower thermal neutron cross-section cladding than current Zr cladding while increasing the ability of the fuel to resist high temperatures (~2000°C) in the event of beyond design basis accidents. The economic and safety benefits of the new fuel and fuel cladding designs could prove beneficial to CANDU reactors.