PERBANDINGAN DENSITAS PELET UO2 HASIL PELETISASI MENGGUNAKAN SERBUK DAN MIKROSPIR

A COMPARISON OF PELLETS DENSITIES IN PELLETIZATION PROCESS USING UO2 POWDER AND UO2 MICROSPHERE. A pelletization process UO2 fuel has been developed using UO2 microsphere as a substitute of UO2 powder. Microspheres are spherical, free flowing and porous with certain hardness (soft particle). The benefit of using microsphere in pelletization process is dust free in compaction and more effective in packing so the granulation process and solid lubricants are not required. It is hypothesized that the use of UO2 microsphere in the pelletization process will provide higher sintered pellet density than UO2 powder at the same pelletization process parameters. UO2 microsphere size used in this pelletization was 900 μm with crushing strength of 2.0 N / particles while the UO2 powder size between 150 and 850 μm. The pelletization processes of UO2 microsphere and UO2 powder were performed by varying the compacting pressure between 200Mpa up to 500MPa and sintered at temperatures of 1100 °C for 6 hours in an atmosphere of hydrogen and nitrogen gas mixture. Characterizations performed on the green and sintered pellets of UO2 microsphere and UO2 powder were dimension measurements, weighing and densities measurements. The densities of green and sintered pellets of UO2 microsphere were higher than the green and sintered pellets densities of UO2 powder with corresponded compaction pressure variations. The results indicate that the density of the green pellets both compaction results UO2 powder and UO2 mikrospir increased with increasing compacting pressure. Mikrospir UO2 pellets density crude ranged from 82.1 to 84.2% TD. At the same sintering conditions, both Compaction UO2 powder and UO2 mikrospir Compaction shows the density increases with the greater pressure compacting process. The sintered pellets densties of UO2 obtained from this research were not appropriate with density requirements of PWR fuel. It is necessary to perform advanced research related to the effective pelletization process parameters and UO2 microsphere specifications in providing the appropriate sintered pellets densities.