Patent Number: 059784318
Section: claims

1. A method of producing mixed oxide fuel pellets for use in a nuclear reactor, the mixed oxide comprising oxides of at least two fissile elements, the method including the steps of: (i) providing the mixed oxide with a neutron poison to form a fuel;  (ii) milling the fuel to form a fuel powder;  (iii) treating the milled fuel with a binderless spheroidising step such that the fuel powder is formed into substantially homogeneous agglomerated granules; and  (iv) pressing and sintering the fuel resulting from the spheroidising step (iii) to produce a fuel pellet having a continuous homogeneous mixture of the mixed oxide and the neutron poison. 2. A method according to claim 1, in which the fissile elements comprise uranium and plutonium. 3. A method according to claim 1, in which the neutron poison is gadolinia. 4. A method according to claim 1, in which one or more additives are introduced in order to enhance the quality of the fuel pellets. 5. A method according to claim 1, in which the neutron poison is present at between about 0.5 to 10 wt %. 6. A method according to claim 1, in which the neutron poison is present at between 1 to 3 wt %. 7. A method according to claim 1, in which between 20 and 60 wt % of a first fissile element is added, followed by all or substantially all of the second fissile element, followed by the reminder of the first fissile element and the neutron poison. 8. A method according to claim 1, in which the sintering temperature is between 1400 and 1900.degree. C., and preferably between 1650 and 1750.degree. C. 9. A method according to claim 1, in which sintering is conducted in an atmosphere comprising an H.sub.2 and inert gas mixture. 10. A method according to claim 1, in which a H.sub.2 :Ar or H.sub.2 :N.sub.2 atmosphere is used with 5% H.sub.2. 11. A method according to claim 1, in which the sintering temperature is reached by increasing the temperature at a rate equal to or less than 200.degree. C./hour. 12. A method according to claim 1, in which the temperature is increased up to 1000.degree. C. at a rate of, or of less than 200.degree. C. /hour and the temperature is increased from there to the sintering temperature at a rate of, or of less than 50.degree. C. 13. Fuel produced according to claim 1.