Recent studies in the preparation of ceramic grade uranium dioxide

Experience gained during the manufacturing of ceramic grade uranium dioxide to meet the initial half charge requirement of Ra asthan-1 Reactor, as well as, experimental observations made recently in order to investigate the dependence of the powder characteristics on the mode of its preparation are described. Among the various factors affecting these characteristics, the pH of precipitation widely controls the particle size, density, surface activity and hence sintering and microstructure. However, production of uniform quality of powder under standardised conditions gives rejects of the order of 40%. It was, therefore, attempted to produce UO2 powder by different methods. The results indicate that the UO2 produced through ammonium uranyl carbonate route gives encouraging results. Not only the compacting properties of the oxide powder are improved but also the grain size and uniform porosity. (auth.)