Research on the improvement of particle size adjustment technology of dry recovered powder and the sintered density control

Segawa, Tomoomi ; Kawaguchi, Koichi  ; Ishii, Katsunori ; Yamamoto, Kazuya; Makino, Takayoshi ; Iso, Hidetoshi ; Fukasawa, Tomonori*; Fukui, Kunihiro*

Japan Atomic Energy Agency has been used out of specification mixed oxide (MOX) pellets as a dry recovered powder for the effective use of nuclear fuel material in the MOX fuel fabrication process. The densities of the sintered MOX pellets can be controlled to about 85 %T.D. without adding pore former by adjusting the amount and the particle size of the dry recovered powder into the raw powder. It is required to adjust the particle size of the dry recovered powder to under 250 m, the influence of the operating parameters of the collision plate-type jet mill on the characteristics of pulverization and the influence of pulverized powders on sintering properties were evaluated. The clearance was narrowed, the pulverized powders were confirmed to be adjusted for the particle diameter of under 250 m, and the pellet prepared from the pulverized powder with density of about 85.0 %T.D. was obtained.