Feasibilyty study on a simplified MOX pellet fabrication process, the short process, for fast breeder reactor fuel

Asakura, Koichi; Takeuchi, Kentaro ; Makino, Takayoshi ; Kato, Yoshiyuki 

Technological feasibility of a simplified MOX pellet fabrication process, the short process, was studied. About 300 g MH-MOX powder with adjusted plutonium content to 30% could be successfully processed by a tumbling-granulator for subsequent pelletizing and sintering processes. The granulated 30%PuO-MOX powder could be pressed into green annular pellets directly and smoothly when using a die wall lubrication method. The pellet tensile strengths were compared for a granulated molybdenum powder and they were higher for pellets obtained when using the die wall lubrication method than when using the conventional powder mixing method. The amount of additives in the green pellets could be controlled at 0.06wt% in this process. It is therefore, possible to carry out de-waxing and sintering of green pellets in the same furnace. By controlling the average particle sizes of granulated 30%PuO-MOX powders, pellets with more than 95% theoretical density could be obtained after 1700 C for 2 h. As a result, it can be concluded that the short process is technoligically feasible to fabricate MOX annular pellets.