Development of dry rework technology in MOX fuel fabrication process; Selection and characterization of pulverizer for particle size adjustment of dry recycled powder

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.

Technological development of the particle size adjustment of dry recovered powder

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.

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

Nuclear Technology, 167(3), p.348 - 361, 2009/09

https://doi.org/10.13182/NT09-A9075

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.

Results of basic examinations on the simplified MOX fuel fabrication process (short process), 3; Pellet fabrication tests

Makino, Takayoshi; Okita, Takatoshi; Kato, Akebumi*; Suzuki, Yuichiro*; Minakawa, Susumu; Kashimura, Motoaki

no journal, , 

no abstracts in English

Development of simplified pellet fuel production technology, 2; Processing technology for de-nitration conversion based on microwave heating

Kato, Yoshiyuki; Kimura, Yuichi; Isomae, Hidemi; Kurita, Tsutomu; Yoshimoto, Katsunobu; Makino, Takayoshi; Suzuki, Masahiro; Kihara, Yoshiyuki

no journal, , 

no abstracts in English

Technological development of the particle size adjustment of recycle powder, 3; Optimization study of collision plate-type jet mill

Segawa, Tomoomi; Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Sato, Hisato

no journal, , 

The optimizing the centrifugal classifier which influences the classification performance of collision plate-type jet mill was examined for the purpose of the particle size adjustment of recycle powder the MOX pellets. In order to adjust the particle size of recycle powder to 10-250 m, the pulverization test of the simulated raw powder was carried out using the newly prepared components as a parameter. The prospect that the particle size can be adjusted within the range of 10-250 m for recycle powder was obtained by optimizing the parameter of the centrifugal classifier of collision plate-type jet mill.

Pulverization characteristics of a collision plate type jet mill for particle size adjustment of recovered powder in the MOX fuel fabrication process

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.

Improvement of fireproof performance by sealing the fire-retardant sheet on glove box panels, 1; Influence of burning on glove box panels

Kawasaki, Kohei; Shinada, Kenta; Makino, Takayoshi; Okamoto, Naritoshi

no journal, , 

no abstracts in English

The Evaluation of the properties of the collision-plate-type jet mill for dry recycling of MOX 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.

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*

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.