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Yamamoto, Kazami; Moriya, Katsuhiro; Okita, Hidefumi; Yamada, Ippei; Chimura, Motoki; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Masanobu; Morishita, Takatoshi; et al.
Journal of Neutron Research, 26(2-3), p.59 - 67, 2024/01
The linac and 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex was designed to provide 1-MW proton beams to the following facilities. Thanks to the improvement works of the accelerator system, we successfully accelerate 1-MW beam with quite small beam loss. Currently, the beam power of RCS is limited by the lack of anode current in the RF cavity system rather than the beam loss. Recently we developed a new acceleration cavity that can accelerate a beam with less anode current. This new cavity enables us not only to reduce requirement of the anode power supply but also to accelerate more than 1-MW beam. We have started to consider the way to achieve beyond 1-MW beam acceleration. So far, it is expected that up to 1.5-MW beam can be accelerated after replacement of the RF cavity. We have also been continuing study to achieve up to 2 MW beam in J-PARC RCS.
Yamamoto, Kazami; Moriya, Katsuhiro; Okita, Hidefumi; Yamada, Ippei; Chimura, Motoki; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Masanobu; Morishita, Takatoshi; et al.
Proceedings of 68th ICFA Advanced Beam Dynamics Workshop on High Intensity and High Brightness Hadron Beams (HB2023) (Internet), p.270 - 273, 2023/10
The 3-GeV rapid-cycling synchrotron at the Japan Pro-ton Accelerator Research Complex was designed to provide 1-MW proton beams to the following facilities. Thanks to the improvement works of the accelerator system, we successfully accelerate 1-MW beam with quite small beam loss. Currently, the beam power of RCS is limited by the lack of anode current in the RF cavity system rather than the beam loss. Recently we developed a new acceleration cavity that can accelerate a beam with less anode current. This new cavity enables us not only to reduce requirement of the anode power supply but also to accelerate more than 1-MW beam. We have started to consider the way to achieve beyond 1-MW beam acceleration. So far, it is expected that up to 1.5-MW beam can be accelerated after replacement of the RF cavity. We have also continued study to achieve more than 2 MW beam in J-PARC RCS.
Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Suzuki, Masahiro; Tachihara, Joji; Takato, Kiyoto; Okita, Takatoshi; Satone, Hiroshi*; Suzuki, Michitaka*
Mechanical Engineering Journal (Internet), 8(3), p.21-00022_1 - 21-00022_9, 2021/06
To reduce the hold-up of the nuclear fuel materials in the glove box and the external exposure dose, the technology of the MOX powder adhesion prevention by the nanoparticle coating to the acrylic panels of the glove box has been developed. The surface analysis by means of atomic force microscopy (AFM) showed that the acrylic test piece surface coated with nanoparticles had a higher root mean square roughness value than that non-coated with nanoparticles. Due to the formation of nano-sized tiny rugged surface, the nanoparticle coating reduced the minimum adhesion force between the UO particles and the acrylic test piece surface with the smallest particle size of about 5
m where desorption was observed, by about one-tenth. Moreover, the nanoparticle coating reduced the amount of the MOX powder adhering to the acrylic test piece to about one-tenth. In this study, it was found that applying the nanoparticle coating to the acrylic panels of glove box can prevent the adhesion of nuclear fuel materials. This method is effective for reducing the hold-up of the nuclear fuel materials in the glove box, the external exposure dose and improving the visibility of the acrylic panels.
Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Suzuki, Masahiro; Tachihara, Joji; Takato, Kiyoto; Okita, Takatoshi; Satone, Hiroshi*; Suzuki, Michitaka*
Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08
To reduce the hold-up of the nuclear fuel materials in the glove box and the external exposure dose, the technology of the MOX powder adhesion prevention by the nanoparticle coating to the acrylic panels of the glove box has been developed. Due to the formation of nano-sized tiny rugged surface, the nanoparticle coating reduced the minimum adhesion force between the UO particles and the acrylic test piece surface with the smallest particle size of about 5
m where desorption was observed, by about one-tenth. Moreover, the nanoparticle coating reduced the amount of the MOX powder adhering to the acrylic test piece to about one-tenth. In this study, it was found that applying the nanoparticle coating to the acrylic panels of glove box can prevent the adhesion of nuclear fuel materials. This method is effective for reducing the hold-up of the nuclear fuel materials in the glove box, the external exposure dose and improving the visibility of the acrylic panels.
Suzuki, Kiichi; Okita, Takatoshi; Aono, Shigenori
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 10 Pages, 2017/06
Japan Atomic Energy Agency has developed mixed plutonium-uranium oxide (MOX) fuel fabrication technologies in large-scale and fabricated MOX fuel assemblies for experimental fast reactor "JOYO" and prototype fast reactor "MONJU" at Plutonium Fuel Production Facility (PFPF) since 1988. Low density pellet is adopted as MONJU fuel. For the low density pellet fabrication in large-scale, various challenges were encountered. In order to resolve these challenges, countermeasures such as new pore former with high softening temperature and improved granulation method for MOX powder were considered. In this presentation, accumulated MOX fuel fabrication technologies as mentioned above and recent R&D activity such as new pelletizing method, or die wall lubrication pelletizing, for low-decontaminated TRU fuel fabrication will be discussed.
Takato, Kiyoto; Murakami, Tatsutoshi; Suzuki, Kiichi; Shibanuma, Kimikazu; Hatanaka, Nobuhiro; Yamaguchi, Bungo; Tobita, Yoshimasa; Shinozaki, Masaru; Iimura, Naoto; Okita, Takatoshi; et al.
JAEA-Technology 2013-026, 42 Pages, 2013/10
In order to cope with making a commercial fast reactor fuel burn-up higher, oxygen-to-metal (O/M) ratio in the fuel specification is designed to 1.95. As the test for the fabrication of such low O/M ratio pellets, two kinds of O/M ratio preparation tests of different reduction mechanism were done. In the first test, we evaluated the technology to prepare the O/M ratio low by annealing the sintered pellets in production scale. In addition, we know from past experience that O/M ratio of the sintered pellets can be reduced by residual carbon when the de-waxed pellets with high carbon content are sintered. Thus, in another test, the green pellets containing a large amount of organic additives were sintered and we evaluated the technology to produce the low O/M ratio sintered pellets by the reduction due to residual carbon. From the first test results, we found a tendency that the higher annealing temperature or the longer annealing time resulted in the lower O/M ratio. However, the amount of O/M ratio reduction was small and it is estimated that a substantial annealing time is necessary to prepare the O/M ratio to 1.95. It is considered that reducing O/M ratio by annealing was difficult because atmosphere gas containing oxygen released from pellets remained and the O/M ratio was changed to the value equilibrated with the gas having high oxygen potential. From another test results, it was confirmed that O/M ratio was reduced by the reduction due to residual carbon. We found that it was important to manage an oxygen potential of atmosphere gas in a sintering furnace low to reduce the O/M ratio effectively.
Ono, Takanori; Hatanaka, Nobuhiro; Okita, Takatoshi; Aono, Shigenori
JAEA-Technology 2012-042, 96 Pages, 2013/02
In January of 1993, plutonium dioxide powder was received from the reprocessing plant "La Hague" of COGEMA in France to Plutonium Fuel Production Facility (PFPF) of JAEA to use as feed powder of MOX fuel for FBR prototype "Monju". Since the plutonium dioxide powder was contained in COGEMA type canisters, the powder had to be rebottled from CCGEMA type canisters to JAEA type canisters which can be handled in the PFPF. Therefore feed powder rebottling equipment and temporary feed storage equipment were developed and installed in the PFPF. Rebottling work with their equipments was started from March of 1993 and completed in March of 2006. This report summarizes operating and maintenance experiences on feed powder rebottling equipment and temporary feed storage equipment. It's important to reflect the operating and maintenance experiences of the rebottling equipment into design of a new rebottling equipment for uranium-plutonium mixed oxide powder.
Mizuno, Mineo; Haga, Tetsuya; Sudo, Katsuo; Takeuchi, Kentaro; Okita, Takatoshi; Kihara, Yoshiyuki
JAEA-Technology 2011-009, 100 Pages, 2011/06
Crystalline cellulose granulated to sizes from 70 to 100 micron was previously used as pore former (PF) to fabricate low density MOX pellets for MONJU. When sale of Avicel was discontinued, it became necessary to find a substitute PF. Then, small scale fabrication tests of MOX pellets with candidate PFs were conducted. Three candidate PFs, cellulose beads, CEOLUS and CELPHERE, were examined in the tests. The results are summarized below. (1) The CELPHERE gave MOX pellets with almost same density depression performance as pellets using Avicel, and standards deviation of the sintered densities of pellets was the smallest. (2) MOX pellets with CELPHERE had lower incidence of observable defects. (3) MOX pellets with CELPHERE had almost the same O/M as pellets with Avicel. (4) MOX pellets with CELPHERE had lower incidence of micro cracks. (5) The densification amount of pellets with CELPHERE was almost the same as that of pellets with Avicel. It was concluded CELPHERE was a suitable substitute for Avicel.
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.
Takeuchi, Kentaro; Okita, Takatoshi; Aono, Shigenori
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 4 Pages, 2005/10
In the FBR MOX pellet fabrication process, the characteristics such as specific surface area and homogeneity of the ball milled powder depend on the ball milling condition. The qualities of the MOX pellet such as sintered density and homogeneity are influenced by the characteristics of the ball milled powder. In this work, correlations relationship between properties of milled powder, ball milling condition and characteristic of the MOX pellet have been evaluated.
Ichige, Hidekazu; Hatanaka, Nobuhiro; Iimura, Naoto; Okita, Takatoshi
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no abstracts in English
Mizuno, Mineo; Sudo, Katsuo; Takeuchi, Kentaro; Okita, Takatoshi; Kihara, Yoshiyuki
no journal, ,
The short process is considered to be a main concept which has high feasibility in Fast Reactor Cycle Technology Development (FaCT). In this study, a small-scale fabrication test was carried out to investigate characteristic of MOX pellet made of granulated MOX powder blended with dry-route recycle powder, for the first time, as a basic test concern with the short process. As the results, it was found that the sintered density of the pellet clearly depends on the preparing conditions and content of recycle powder. The results is intended to be utilized in the investigation of engineering-scale test conditions.
Sudo, Katsuo; Makino, Takayoshi; Kato, Akebumi*; Okita, Takatoshi; Suzuki, Masahiro; Kashimura, Motoaki; Kihara, Yoshiyuki; Haga, Tetsuya
no journal, ,
no abstracts in English
Makino, Takayoshi; Okita, Takatoshi; Kato, Akebumi*; Suzuki, Yuichiro*; Minakawa, Susumu; Kashimura, Motoaki
no journal, ,
no abstracts in English
Okita, Takatoshi; Sudo, Katsuo; Kihara, Yoshiyuki; Asakura, Koichi; Ojima, Hisao
no journal, ,
no abstracts in English
Suzuki, Masahiro; Ishii, Katsunori; Kihara, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Okita, Takatoshi; Kashimura, Motoaki; Kato, Masato; Namekawa, Takashi; Fujii, Kanichi
no journal, ,
In FaCT project, we have set major six technologies for success of simplified pellet fuel fabrication. Our schedule on the technical fundamental technology should be completed by 2010, being transferred to the development of a technology for tele-command operation of mass production and facility maintenance until 2015. In this time, we will report current states of FaCT project as well as future plan.
Takeuchi, Kentaro; Okita, Takatoshi; Seki, Masayuki; Takano, Tatsuo; Kato, Akebumi*; Kashimura, Motoaki
no journal, ,
no abstracts in English
Sudo, Katsuo; Okita, Takatoshi; Takeuchi, Kentaro; Takano, Tatsuo; Kato, Akebumi*; Haga, Tetsuya; Yamada, Yoshikazu; Kihara, Yoshiyuki
no journal, ,
no abstracts in English
Takato, Kiyoto; Suzuki, Kiichi; Iimura, Naoto; Okita, Takatoshi
no journal, ,
no abstracts in English