Patent Number: 045129398
Section: claims

1. In a method for the manufacture of oxidic sintered nuclear fuel bodies by compacting UO.sub.2 -starting powder or a mixture of UO.sub.2 and PuO.sub.2 starting powder which contains up to 10% by weight rare-earth oxide as an additive into blanks and subsequent densification of these blanks by a heat treatment in a sintering atmosphere with reducing action, the improvement comprising compacting UO.sub.2 -starting powder which has at least one of the two properties consisting of a specific surface in the range of 2 to 4.5 m.sup.2 /g and a mean crystallite diameter in the range of 80 nm to 250 nm, and carrying out the heat treatment in the sintering atmosphere with reducing action at a temperature in the range of 1,500.degree. C. to 1,750.degree. C. 2. Method according to claim 1, wherein the rare earth oxide is Gd.sub.2 O.sub.3. 3. Method according to claim 1, wherein the temperature of the blanks is held during the heat treatment for a holding time in the range of one hour to ten hours. 4. Method according to claim 1, wherein the blanks are heated up at a heating-up rate in the range of 1.degree. C./min to 10.degree. C./min to the temperature of the heat treatment. 5. In a method for the manufacture of oxidic sintered nuclear fuel bodies by compacting UO.sub.2 -starting powder or a mixture of UO.sub.2 - and PuO.sub.2 starting powder which contains up to 10% by weight rare-earth oxide as an additive into blanks and subsequent densification and these blanks by a heat treatment in a sintering atmosphere with reducing action, the improvement comprising compacting UO.sub.2 -starting powder which has a specific surface in the range of 2 to 4.5 m.sup.2 /g and carrying out the heat treatment in the sintering atmosphere with reducing action at a temperature in the range of 1,500.degree. C. to 1,750.degree. C. 6. Method according to claim 5, wherein the rare earth oxide is Gd.sub.2 O.sub.3. 7. Method according to claim 5, wherein the temperature of the blanks is held during the heat treatment for a holding time in the range of one hour to ten hours. 8. Method according to claim 5, wherein the blanks are heated up at a heating-up rate in the range of 1.degree. C./min to 10.degree. C./min to the temperature of the heat treatment. 9. In a method for the manufacture of oxidic sintered nuclear fuel bodies by compacting UO.sub.2 -starting powder or a mixture of UO.sub.2 - and PuO.sub.2 starting powder which contains up to 10% by weight rare-earth oxide as an additive into blanks and subsequent densification of these blanks by heat treatment in a sintering atmosphere with reducing action, the improvement comprising compacting UO.sub.2 - starting powder which has a mean crystallite diameter in the range of 80 nm to 250 nm, and carrying out the heat treatment in the sintering atmosphere with reducing action is carried out at a temperature in the range of 1,500.degree. C. to 1,750.degree. C. 10. Method according to claim 9, wherein the rare-earth oxide is Gd.sub.2 O.sub.3. 11. Method according to claim 9, wherein the temperature of the blanks is held during the heat treatment for a holding time in the range of one hour to ten hours. 12. Method according to claim 9, wherein the blanks are heated up at a heating-up rate in the range of 1.degree. C./min to 10.degree. C./min to the temperature of the heat treatment.