Reduced Enrichment Fuels for Canadian Research Reactors

Abstract

Fuels consisting of dispersions of USiAl in aluminum are under development for use in Canadian test reactors (NRX and NRU). The fuels have a sufficiently high uranium density that the U-235 enrichment may be reduced to 20% from the 93% currently used in aluminum-uranium alloy fuels. The reduced enrichment is intended to reduce the risk of illegal diversion for weapons proliferation. Our experience has been encouraging. We have developed manufacturing techniques and produced materials whose properties have proven satisfactory with regard to thermal conductivity, aqueous corrosion, strength and ductility, and high temperature swelling resistance. The prime candidate NRU replacement fuel material A1-61.5 wt% (U, 3.5 wt% Si, 1.5 wt% Al) has been irradiated to 80 atomic percent burnup without incident.