초록 ▼

Sulphidation method for a UO2 powder, in which said powder is sulfurated by bringing it into contact with a gaseous sulphidation agent. Method for manufacturing nuclear fuel pellets based on uranium oxide, or mixed oxide of uranium and plutonium, from a load of totally or partially sulfurated UO2 po

Sulphidation method for a UO2 powder, in which said powder is sulfurated by bringing it into contact with a gaseous sulphidation agent. Method for manufacturing nuclear fuel pellets based on uranium oxide, or mixed oxide of uranium and plutonium, from a load of totally or partially sulfurated UO2 powder or UO2 powder and PuO2 powder, by lubrication, pelletizing and sintering, in which: the load of powder subjected to the lubrication, pelletizing and sintering is prepared by the following successive steps: sulphidation of a UO2 powder by the above sulphidation method; optionally mixing, said sulfurated powder in a matrix comprising a UO2 powder, or of a UO2 powder and a PuO2 powder; and, subjecting said load, formed from said sulfurated powder or said mixture, to lubrication, pelletizing and sintering operations.

대표청구항 ▼

The invention claimed is: 1. A sulfidation method for a UO2 powder comprising sulfurating the UO2 powder by bringing the powder into contact with a gaseous sulfidation agent at a temperature from 800째 C. to 1200째 C. wherein the sulfidation agent comprises 2.5% to 25% of H2S, from 37.5% to 72.5% of

The invention claimed is: 1. A sulfidation method for a UO2 powder comprising sulfurating the UO2 powder by bringing the powder into contact with a gaseous sulfidation agent at a temperature from 800째 C. to 1200째 C. wherein the sulfidation agent comprises 2.5% to 25% of H2S, from 37.5% to 72.5% of hydrogen, and from 60% to 2.5% of inert gas, and the sulfidation is carried out for a period of time of 1 to 11 hours. 2. The method according to claim 1, wherein the inert gas is argon or nitrogen. 3. The method acc6rding to claim 1, wherein the gaseous sulfidation agent with hydrogen and/or the inert gas has a total gas flow rate from 1 to 500 ml/mm. 4. The method according to claim 3, wherein the gaseous mixture has a total gas flow rate of 200 ml/mm. 5. The method according to claim 1, wherein the sulfurating is carried out at a temperature from 970째 C. to 980째 C. for a period of time from 1 to 11 hours. 6. A method for manufacturing nuclear fuel pellets based on uranium oxide, or mixed oxide of uranium and plutonium, from a load of totally or partially sulfurated UO2 powder or mixture of UO2 powder and PuO2 powder, the method comprising: (a) sulfurating a UO2 powder by bringing the powder into contact with a gaseous sulfidation agent comprising H2S, hydrogen and inert gas; (b) optionally mixing the sulfurated powder in a matrix comprising a UO2 powder or comprising a UO2 powder and a PuO2 powder; and (c) subjecting the load of the sulfurated powder or of the mixture of the sulfurated powder and the matrix to lubrication, pelletizing and sintering operations, wherein the level of sulfur in the load subjected to the lubrication, pelletizing and sintering operations is from 50 ppm to 1%. 7. The method according to claim 6, wherein the silfurated powder is incorporated in the matrix by simple mixing. 8. The method according to claim 6, wherein the level of sulfur in the load subjected to the lubrication, pelletizing and sintering operations is fiom 100 ppm to 1000 ppm. 9. The method according to claim 6, wherein all or part of the matrix subjected to the lubrication, pelletizing and sintering operations is subjected, prior to the lubrication operation, to a grinding operation. 10. The method according to claim 9, wherein the grinding operation is performed in a ball mill. 11. The method according to claim 6, wherein all or part of the UO2 powder in the load is a powder that has been subjected, prior to grinding, to a reducing treatment such that the powder has an O/U atomic ratio of 2.00 to 2.04. 12. The method according to claim 6, wherein a pore forming agent is incorporated in the load during lubrication. 13. The method according to claim 6, wherein the pelletizing operation is canied out using a hydraulic press. 14. The method according to claim 6, wherein the sintering operation is carried out at a temperature between 1650째 C. and 1750째 C. in a hydrogenated atmosphere. 15. The method according to claim 14, wherein the sintering operation is carried out at a temperature of 1700째 C. in a hydrogenated atmosphere. 16. The method according to claim 14, wherein the atmosphere is humidified. 17. The method according to claim 6, wherein the pellets produced are subjected to dry precision grinding.