Investigations of an advanced fuel form are currently under way. This new fuel form, referred to as evolutionary mixed oxide (EMOX), is a slight perturbation on standard mixed-oxide (MOX) fuel, and analyses show that it can be an effective plutonium management tool in existing light water reactors. The addition of a small fraction of calcia-stabilized zirconia to the uranium-plutonium oxide matrix allows for greater plutonium conversion while also providing a licensing path forward toward eventual implementation of higher-plutonium-destruction fuels. These fuels, referred to as nonfertile (NF) fuels, achieve their high destruction rates through the absence of uranium, which breeds plutonium, in the fuel composition.
Extensive calculations have been performed to assess the feasibility of incorporating the EMOX fuel form into existing pressurized water reactor systems, and the results are given in detail. Specifically, calculations have been made to determine the plutonium consumption achievable by the EMOX concept, and comparisons have been made of this performance to that of typical MOX and NF fuels. The results indicate that EMOX and NF fuels can provide flexibility with regard to controlling plutonium inventories in spent fuel. In addition, fabrication experiments have been conducted to determine the feasibility of fabricating suitable EMOX and NF fuels. NF and EMOX fuels have been fabricated using the solid-state reaction method. Precursor powders were successfully blended and milled using a combination of ball milling and high-energy vibratory milling. Sintering data for EMOX fuel indicated that significant densification occurred at a temperature of 1700°C.
