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Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori
JAEA-Technology 2021-002, 31 Pages, 2021/05
JAEA-Technology-2021-002.pdf:4.37MB
In the MOX fuel fabrication process, a dry recycle technology has been developed to effectively utilize dry recovered powder obtained by crushing out of specification MOX pellets. The particle size of the dry recovery powder is divided into three classes; coarse size (about 250 
m or less), medium size (about 100 m or less), and fine size (about 10 m or less) by the current crushers, and the effect of controlling the density of sintered pellets is obtained to a certain extent by adding the dry recovered powder to the raw powder. In this report, with the aim of more finely adjusting the particle size of the dry recovery powder, a buhrstone mill and a collision plate-type jet mill were selected as grinders that can adjust the dry recovered powder within a particle size range of 250 m or less, and the particle size adjustment test was conducted to pulverize the tungsten-carbide-cobalt (WC-Co) pellets as a simulated material for the MOX pellets. The buhrstone mill can control the particle size within a certain range by adjusting the grindstone clearance, but particles with a particle size of 250 m or more may be discharged. On the contrary, it is expected that the particle size of the collision plate-type jet mill can be controlled in the range of 250 m or less by adjusting the classification zone clearance. Therefore, the collision plate-type jet mill is more suitable for adjusting the particle size of the dry recovered powder than the buhrstone mill.
Kawaguchi, Koichi; Segawa, Tomoomi; Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Ishii, Katsunori
no journal, ,
The reworking of out of specification pellets is required for the effective use of nuclear fuel material and for reduction of the plutonium inventory in fuel fabrication facilities. It is known that the sintering density of mixed oxide pellets can be controlled without a pore-former by controlling the amount and particle size of the recovered powder in the raw powder. The collision plate type jet mill was separated into the classifier and the mill chamber, and these modules were used independently. The peak position shifted to smaller sizes gradually over the five cycles of classification and pulverization. The collision plate type jet mill is a promising form of equipment to obtain particles with objective sizes as the main component of a powder.
Kawaguchi, Koichi; Segawa, Tomoomi; Ishii, Katsunori
no journal, ,
JAEA has developed the fuel powder recycling technology, in which the scrap pellet is pulverized and mixed into raw fuel powder. By analyzing particle size distribution before and after pulverization, it is shown that the pulverized powder consist of 3 types of particles with different character of particle size distribution. Furthermore the prediction method for particle size distribution of pulverized powder was investigated.