Sintered uranium monocarbide with low oxygen content

A process for producing uranium monocarbide fuel with low gas release is provided for fast breeder reactors. The process comprises the steps of: 1) mixing excess carbon with UC2, 2) reducing the oxygen content to UCsub(2+x), where x is less than 1, by vacuum heating, and thereafter allowing oxygen to balance with excess carbon by heating at 1,8000C or higher, and 3) converting UCsub(2+x) into UCsub(1+x) with hydrogen, and thereafter removing hydrogen by vacuum heating. In embodiments, calculated amounts of UO2 powders and graphite powders were mixed in a ball mill for 6 hours and were pelletized under 1-3 ton/cm2. The pellets were heated in a vacuum furnace to a temperature between 1,8000 and 1,8500C at a rate of 3000C/hr and were kept at the elevated temperature for 2 hours. Crude pellets of UCsub(1.85) were produced. After the crude pellets were comminuted in a ball mill, they were compacted under 1-3 ton/cm2. The compacted pellets were heated in a zirconium crucible with H2 at 1,5000C/hr to produce UCsub(1+x). The reaction UC2+H2 → UC+CH4(g) takes place at a temperature from 2000 to 3000C. Another reaction UC2+H2 → UC+C2H4 takes place at a temperature higher than 3000C. The lubricant vaporizes at 7000-9000C. Either hypo or hyper UC can be obtained by controlling conditions at 1,0000C for 2-3 hours. The density of a product sintered at 1,5500C without H2 is 80%-85%. (Iwakiri, K.)