Patent Number: 059995858
Section: claims

1. A fuel material for a nuclear reactor, said fuel material being devoid of ceric oxide and comprising a ceramic material based on stoichiometric UO.sub.2 Th.sub.2 and/or PuO.sub.2 in which is dispersed 0.1 to 2% by weight of at least one elemental metal able to trap oxygen for forming an oxide, whose free formation enthalpy is equal to or below the free formation enthalpy of the superstoichiometric oxide UO.sub.2+x, (U, Th)O.sub.2+x and/or (U, Pu)O.sub.2+x with x such that 0&lt;x.ltoreq.0.01 at the temperature reached in the nuclear reactor. 2. The fuel material according to claim 1, wherein the metal is able to form an oxide having an oxygen potential defined by the formula: EQU .DELTA.G(O.sub.2)=RTLn (pO.sub.2) 3. The fuel material according to claim 1 or 2, wherein the metal is chosen from the group consisting of Cr, Mo, Ti, Nb and U. 4. The fuel material according to claim 3, wherein the metal is Cr and the Cr content of the fuel material is 0.1 to 1% by weight. 5. The fuel material according to claim 4, wherein the chromium content is 0.2 to 0.5% by weight. 6. The fuel material according to claim 1 or 2, wherein the ceramic material is a mixed oxide of UO.sub.2 and a rare earth oxide.