Patent Number: 047740515
Section: claims

1. A method of producing a sintered nuclear fuel compact with which reactivity losses in a nuclear reactor having long fuel element cycles are avoided, which comprises, forming a compact of a mixture of powders containing at least one nuclear fuel oxide selected from the group consisting of UO.sub.2, PuO.sub.2, ThO.sub.2, mixed oxide (U, Pu)O.sub.2 and mixed oxide (U, Th)O.sub.2, at least one neutron poison selected from the group consisting of UB.sub.x, where x=2; 4 and/or 12 and B.sub.4 C, and sintering the compact of the mixture of powders so that the neutron poison is embedded in a sintered matrix of the nuclear fuel oxide at a treatment temperature in a range from 1000.degree. C. to 1400.degree. C. in an oxidizing sintering atmosphere, and then heat treating the sintered compact in a reducing gas atmosphere. 2. A method as defined by claim 1, wherein the nuclear fuel oxide component of the mixture of powders selected from the group consisting of UO.sub.2, PuO.sub.2, ThO.sub.2, (U, Pu)O.sub.2 and (U, Th)O.sub.2 have a total content of fluorine which is less than 100 ppm. 3. A method as defined by claim 1, wherein the nuclear fuel oxide component of the mixture of powders selected from the group consisting of UO.sub.2, PuO.sub.2, ThO.sub.2, (U, Pu)O.sub.2 and (U, Th)O.sub.2 powder, have a mean particle diameter in the range from 5 .mu.m to 100 .mu.m. 4. A method according to claim 1, wherein the oxidizing sintering atmosphere is a carbon dioxide atmosphere, and the reducing gas atmosphere is a hydrogen atmosphere.