Development of nonfertile and evolutionary mixed-oxide nuclear fuels for use in existing water reactors

Investigations of an advanced fuel form are currently under way. This new f uel form, referred to as evolutionary mixed oxide (EMOX), is a slight pertu rbation on standard mixed-oxide (MOX)fuel, and analyses show that it can be an effective plutonium management tool in existing light water reactors. T he addition of a small fraction of calcia-stabilized zirconia to the uraniu m-plutonium oxide matrix allows for greater plutonium conversion while also providing a licensing path forward toward eventual implemetation of higher plutonium-destruction fuels. These fuels, referred to as nonfertile (NF)fu els, achieve their high destruction rates through the absence of uranium wh ich breeds plutonium, in the fuel composition. Extensive calculations have been performed to assess the feasibility of inc orporating the EMOX fuel form into existing pressurized water reactor syste ms, and the results are given in detail. Specifically, calculations have be en made to determine the plutonium consumption achievable by the EMOX conce pt, and comparisons have been made of this performance to that of typical M OX and NF fuels. The results indicate that EMOX and NF fuels can provide fl exibility with regard to controlling plutonium inventories in spent fuel. I n addition, fabrication experiments have been conducted to determine the fe asibility of fabricating suitable EMOX and NF fuels. NF and EMOX fuels have been fabricated using the solid-stare reaction method. Precursor powders w ere 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 degrees C.