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Kageyama, Tomio; Denuma, Akio; Koizumi, Jin*; Odakura, Manabu*; Haginoya, Masahiro*; Isaka, Shinichi*; Kadowaki, Hiroyuki*; Kobayashi, Shingo*; Morimoto, Taisei*; Kato, Yoshiaki*; et al.
JAEA-Technology 2022-033, 130 Pages, 2023/03
JAEA-Technology-2022-033.pdf:9.87MB
Uranium handling facility for development of nuclear fuel manufacturing equipment (Mockup room) was constructed in 1972. The Mockup room has a weak seismic resistance and is deteriorating with age. Also, the original purpose with this facility have been achieved and there are no new development plans using this facility. Therefore, interior equipment installed in this facility had been dismantled and removed since March 2019. After that, the Mockup room was inspected for contamination, and then controlled area in the Mockup room was cancelled on March 29th 2022. A total of 6,549 workers (not including security witnesses) were required for this work. The amount of non-radioactive waste generated by this work was 31,300 kg. The amount of radioactive waste generated by this work was 3,734 kg of combustible waste (103 drums), 4,393 kg of flame resistance waste (61 drums), 37,790 kg of non-combustible waste (124 drums, 19 containers). This report describes about the dismantling and removing the interior equipment in the Mockup room, the amount of waste generated by this work, and procedure for cancellation the controlled area in the facility.
Shinozaki, Masaru; Aita, Takahiro; Iso, Takahito*; Odakura, Manabu*; Haginoya, Masahiro*; Kadowaki, Hiroyuki*; Kobayashi, Shingo*; Inagawa, Takumu*; Morimoto, Taisei*; Iso, Hidetoshi; et al.
JAEA-Technology 2021-043, 100 Pages, 2022/03
JAEA-Technology-2021-043.pdf:7.49MB
It is planned that the MOX (Mixed Oxide) from the decommissioned facilities in Nuclear Fuel Cycle Engineering Laboratories is going to be consolidated and stored stably and safely for a long term in Plutonium Fuel Production Facility of the Plutonium Fuel Development Center of Nuclear Fuel Cycle Engineering Laboratories. For this purpose, it is necessary to pelletize nuclear fuel materials in the facility and store them in the assembly storage (hereinafter referred to as "waste packaging work") to secure storage space in the plutonium material storage. As a countermeasure to reduce the facility risk in this waste packing work, it was decided to construct a new powder weighing and homogenization mixing facility to physically limit the amount (batch size) of nuclear fuel materials handled at the entrance of the process. In order to secure the installation space for the new facility in the powder preparation room (1) (FP-101), the pre-dismantling temporary waste storage facility 3 (FPG-03a, b, c) was dismantled and removed. This facility consists of a granulating and sizing facility, an additive mixing facility, and a receiving and delivering guided facility, which started to be used from January 1993, and was discontinued on February 3, 2012 and became a waste facility. Subsequently, the dismantling and removal of the interior equipment was carried out by pellet fabrication section for glove operation to reduce the amount of hold-up, and before the main dismantling and removal, there was almost no interior equipment except for large machinery. This report describes the dismantling and removal of the glove box and some interior equipment and peripherals of the facility, as well as the Green House setup method, dismantling and removal procedures, and issues specific to powder process equipment (dust, etc.).
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.
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.
Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Sato, Hisato
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.
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.
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.
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.
Yamamoto, Kazuya; Segawa, Tomoomi; Makino, Takayoshi; Kawaguchi, Koichi; Iso, Hidetoshi; Ishii, Katsunori
no journal, ,
no abstracts in English
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.
Yamamoto, Kazuya; Segawa, Tomoomi; Makino, Takayoshi; Kawaguchi, Koichi; Iso, Hidetoshi; Ishii, Katsunori
no journal, ,
no abstracts in English
