Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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
Funtai Kogakkai-Shi, 57(9), p.478 - 484, 2020/09
A collision plate type jet mill is assumed to be a pulverizer that can control the particle size for nuclear fuel fabrication. The collision plate type jet mill consists of two modules, a classifier and a mill chamber. Coarse component of powder is cycled in the equipment and finally pulverized into objective particle size. In this report, simulated crushed powders were classified and pulverized step by step, and particle size distribution were compared. The collision plate type jet mil can produce objective size particles with low overgrinding.
Segawa, Tomoomi; Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Kawaguchi, Koichi; Ishii, Katsunori; Sato, Hisato; Fukasawa, Tomonori*; Fukui, Kunihiro*
Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.738 - 745, 2019/09
In the MOX fuel fabrication process, the dry grinding technology of mixed oxide pellets have been developed for the effective use of nuclear fuel materials. To develop a technology to control the particle size of dry recovered powder, the performance of the buhrstone mill and the collision plate type jet mill were studied using a simulated powder of particle size distribution about 500 m. We found that the particle size can be controlled at the range of about 250 m or less by both by adjusting the clearance between the grinding wheels of the buhrstone mill, and the clearance and elevation angle of the clarification zone of the collision plate type jet mill. And furthermore, the collision plate type jet mill is considered to be suitable for particle size control because the operating parameters of the classifier can be finely adjusted.
Deki, Manato*; Oka, Tomoki*; Takayoshi, Shodai*; Naoi, Yoshiki*; Makino, Takahiro; Oshima, Takeshi; Tomita, Takuro*
Materials Science Forum, 778-780, p.661 - 664, 2014/02
Times Cited Count：2 Percentile：72.41(Crystallography)no abstracts in English
Asakura, Koichi; Takeuchi, Kentaro; Makino, Takayoshi; Kato, Yoshiyuki
Nuclear Technology, 167(3), p.348 - 361, 2009/09
Times Cited Count：4 Percentile：30.36(Nuclear Science & Technology)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.
Makino, Takayoshi; Okita, Takatoshi; Kato, Yoshiyuki; Kurita, Tsutomu; Takahashi, Yoshiharu; Aono, Shigenori
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 5 Pages, 2005/10
A simplified MOX pellet fabrication process, called short process, has been developed to drastically reduce fuel fabrication cost.The MH powder has characteristic of fine particle and low flowability. It is difficult to pelletize the MH powder directly without granulation into smaller size FR pellet compared with LWR fuel. Therefore, small-scale hot tests to improve the flowability of the MH powder has been carried out using two kinds of methods, and quality of the pellet was evaluated.
Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Sato, Hisato
no journal, ,
no abstracts in English
Makino, Takayoshi; Yamamoto, Kazuya; Segawa, Tomoomi; Kawaguchi, Koichi; Iso, Hidetoshi
no journal, ,
The purpose of this study is to develop technology of the particle size adjustment of dry recovered powder of MOX pellets. Pulverization and classification experiments were conducted using simulated pellets obtained from materials having similar hardness and different density (specific gravity). We report that the results of pulverization and classification experiments in which experimental parameters were the clearance of the centrifugal classifier affecting the classification performance of the collision plate type jet mill.
Shinada, Kenta; Kawasaki, Kohei; Makino, Takayoshi; Okamoto, Naritoshi
no journal, ,
no abstracts in English
Kawasaki, Kohei; Shinada, Kenta; Makino, Takayoshi; Okamoto, Naritoshi
no journal, ,
no abstracts in English
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; Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Ishii, Katsunori
no journal, ,
Collision plate type jet mill is a promissing pluverizer which can adjust particle size of a recycling powder in dry recycling of MOX fuel scrap pellet in a fuel manufacturing process for fast reactors. The equipment consists of a classifier chamber and a pluverizer chamber, and particle size of collected powder can be adjusted by controling the operational parameter of the classifier. The examination focused on the pluverizer was performed, and it was confirmed that coarse component is pluverized without overgrinding.
Yamamoto, Kazuya; Segawa, Tomoomi; Makino, Takayoshi; Kawaguchi, Koichi; Iso, Hidetoshi; Ishii, Katsunori
no journal, ,
no abstracts in English
Ishii, Katsunori; Segawa, Tomoomi; Kawaguchi, Koichi; Nishina, Masahiro; Makino, Takayoshi; Natori, Yuri*
no journal, ,
JAEA is developing simplified a plutonium and uranium mixed oxide (MOX) pellet fabrication process. In this process, agitation granulator improves flowability of MOX powder with water as binder. This granulation method has issues, including low production capacity due to criticality control for wet nuclear material. A new simple additive-free dry granulation method was proposed recently to produce tritium breeding LiO spheres for nuclear fusion reactor. In this research, results of experiments to investigate the applicability of the new granulation method to MOX powder is reported.
Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Fukasawa, Tomonori*; Fukui, Kunihiro*
no journal, ,
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.
Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Nishina, Masahiro; Makino, Takayoshi; Natori, Yuri*; Ikemoto, Norihiro*; Yonehara, Kazuo*; Tatenuma, Katsuyoshi*
no journal, ,
Japan Atomic Energy Agency has researched and developed a simplified MOX pellet fabrication process. the flowability of MOX powder is improved by a tumbling granulation method using water as a binder. However, in this granulation method, improvement of the production capacity under criticality control for wet nuclear material is an issue. In recent years, an additive-free dry granulation technology has proposed as a novel granulation method for producing tritium breeding LiO spheres for nuclear fusion reactor. In this study, to confirm the applicability of this method to the MOX fuel fabrication process, CeO powder was used as a simulated material of MOX powder as a basic test for mechanization, and the influence of mechanical external force on granulation was confirmed and evaluated. As a result of the test, good granulation property was obtained by applying a mechanical external force of vertical vibration, and it was possible to obtain the prospect of mechanization of the dry granulation process.
Hirooka, Shun; Okumura, Kazuyuki; Makino, Takayoshi
no journal, ,
no abstracts in English
Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Nishina, Masahiro; Makino, Takayoshi; Iimura, Kenji*; Satone, Hiroshi*; Suzuki, Michitaka*; Natori, Yuri*
no journal, ,
Japan Atomic Energy Agency has developed a simplified pelletizing fuel fabrication system. In this system, the flowability of a MOX raw powder is improved by wet granulation for the pelletizing process, and the die wall lubrication method directly presses the granulated MOX powder into green pellets without adding any lubricant into the powder. The homogeneous compression is important to fabricate high-density green pellets. However, it is difficult to observe the compaction behavior in situ. Therefore, the capping phenomenon was investigated by using X-ray computed tomography and alumina powder that is highly transparent against X-rays. When lubricant was used, the breakage of the particles extended to the bottom compared with not used. This result indicates that the die wall lubrication is effective for the homogeneous compression of granulated powders.
Kawaguchi, Koichi; Yamamoto, Kazuya; Segawa, Tomoomi; Ishii, Katsunori; Makino, Takayoshi; Iso, Hidetoshi
no journal, ,
Pellet sintering density data obtained from experiments changing the mixing ratio of simulated raw material powder and simulated dry recovery powder from 10:0 to 0:10 were analyzed. A method of predicting the pellet sintering density from particle size distribution of the dry recovery powder and the mixing ratio was examined.
Nishina, Masahiro; Takato, Kiyoto; Nakamichi, Shinya; Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Makino, Takayoshi; Okumura, Kazuyuki
no journal, ,
no abstracts in English
