Sintering experiments of DyZrN under a variety of milling conditions

Takaki, Seiya  ; Harada, Makoto; Takano, Masahide 

It is necessary to control the pellet densities for the purpose of securing margin against swelling for nitride fuel for transmutation of minor actinide (MA). Appropriate polymer particles will be applied as a pore former in order to decrease the density. This study aimed to investigate the influence of various milling parameters on the densities of sintered DyZrN solid solution as surrogate nitride fuel in order to obtain fundamental knowledge for controlling sintered density with pore former. The sintered pellet densities are studied under various milling time (from 10 to 150 min) and employing either tungsten carbide (WC) or silicon nitride (SiN) milling cup and balls. The measurement of specific surface area clarifies that finer powder can be obtained with WC. However, the achieved densities of the sintered pellets, as a function of specific surface area of the milled powder, show that the denser pellets can be obtained with SiN in spite of the smaller specific surface area. These results suggest that the distortion in the powder particles influences the behaviour of grain growth during the sintering.