Nuclear fuel

Claim 1

A process for producing a sintered uranium dioxide body useful as nuclear fuel wherein the uranium dioxide grains have an average grain size ranging from about 30 microns to about 80 microns and wherein at least about 99% by volume of the uranium dioxide grains are each coated with glassy magnesium aluminosilicate phase leaving no significant portion thereof exposed, said body having a porosity ranging from about 2% by volume to less than about 10% by volume, which consists essentially of providing uranium dioxide power containing a fissionable substance, providing a sintering agent having a composition encompassed and defined by polygon ABCD excluding lines AB and CD of Figure 1 or precursor therefor, admixing said sintering agent or precursor therefor with said uranium dioxide to give said sintering agent composition ranging from about 0.1% by weight to about 0.8% by weight of a sinterable mixture consisting essentially of said centering agent composition and uranium dioxide, forming the resulting mixture into a compact, sintering said compact at a temperature at which said sintering agent forms a liquid phase ranging from greater than about 1500° C. to a temperature at which there is no significant vaporization of said SiO 2 under conditions wherein the oxygen to uranium atomic ratio ranges from about 1.7 to about 2.25 to produce a sintered product having said average grain size and cooling said product to produce said sintered body, said precursor thermally decomposing below said sintering temperature.