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Kawasaki, Kohei; Ono, Takanori; Shibanuma, Kimikazu; Goto, Kenta; Aita, Takahiro; Okamoto, Naritoshi; Shinada, Kenta; Ichige, Hidekazu; Takase, Tatsuya; Osaka, Yuki; et al.
JAEA-Technology 2022-031, 91 Pages, 2023/02
The document for back-end policy opened to the public in 2018 by Japan Atomic Energy Agency (hereafter, JAEA) states the decommissioning of facilities of Nuclear Fuel Cycle Engineering Laboratories and JAEA have started gathering up nuclear fuel material of the facilities into Plutonium Fuel Production Facilities (hereafter, PFPF) in order to put it long-term, stable and safe storage. Because we planned to manufacture scrap assemblies almost same with Monju fuel assembly using unsealed plutonium-uranium mixed-oxide (hereafter, MOX) powder held in PFPF and transfer them to storage facilities as part of this "concentration" task of nuclear fuel material, we obtained permission to change the use of nuclear fuel material in response to the new regulatory Requirements in Japan for that. The amount of plutonium (which is neither sintered pellets nor in a lidded powder-transport container) that could be handled in the pellet-manufacturing process was limited to 50 kg Pu or less in order to decrease the facility risk in this manufacture. Therefore, we developed and installed the "MOX weighing and blending equipment" corresponding with small batch sizes that functioned in a starting process and the equipment would decrease handling amounts of plutonium on its downstream processes. The failure data based on our operation and maintenance experiences of MOX fuel production facilities was reflected in the design of the equipment to further improve reliability and maintainability in this development. The completed equipment started its operation using MOX powder in February 2022 and the design has been validated through this half-a-year operation. This report organizes the knowledge obtained through the development of the equipment, the evaluation of the design based on the half-a-year operation results and the issues in future equipment development.
Yamada, Yoshikazu; Shibanuma, Kimikazu
Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.648 - 654, 2019/09
During a periodic inspection, multiple spot-like nuclear material contamination (maximum 21.7 Bq) was detected at the outer surface of a glove-box (GB) body used to install equipment for fabricating mixed oxide (MOX) fuel at the Japan Atomic Energy Agency. The inspection confirmed a total of 13 cracks passing through the thickness direction of the GB and a bleeding phenomenon was observed on the polyvinyl chloride (PVC) cables in the GB. These cracks were judged as stress corrosion cracking induced by the generation of chlorine gas by irradiation of PVC cables lying against the inner surface of the GB.
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.
Murakami, Tatsutoshi; Shibanuma, Kimikazu; Hanawa, Yukio; Yamaki, Takao; Suzuki, Mitsuru; Aono, Shigenori
no journal, ,
MOX powder containing organic additives is loaded in a hopper. The hopper has a cooling function to mitigate heat deterioration of organic additives, but its cooling may not be enough for higher order plutonium in the future. So temperature measurement of MOX powder in the hopper was carried out as a preliminarily test for development of cooling hopper.
Murakami, Tatsutoshi; Suzuki, Kiichi; Shibanuma, Kimikazu; Aono, Shigenori
no journal, ,
no abstracts in English
Murakami, Tatsutoshi; Shibanuma, Kimikazu; Yamaguchi, Bungo; Takato, Kiyoto; Suzuki, Kiichi; Aono, Shigenori
no journal, ,
no abstracts in English
Takato, Kiyoto; Shibanuma, Kimikazu; Suzuki, Kiichi; Murakami, Tatsutoshi; Aono, Shigenori
no journal, ,
no abstracts in English
Kawasaki, Kohei; Shinada, Kenta; Okamoto, Naritoshi; Ono, Takanori; Shibanuma, Kimikazu; Goto, Kenta
no journal, ,
Plutonium Fuel Production Facility of JAEA plans to produce waste packages with stable sealed state by processing MOX powder into pellet. Therefore, we have developed Weighting and blending equipment with improved reliability and maintainability based on experience of operation and maintenance the fast reactor MOX fuel.
Goto, Kenta; Hirooka, Shun; Horii, Yuta; Nakamichi, Shinya; Murakami, Tatsutoshi; Shibanuma, Kimikazu; Ono, Takanori; Yamamoto, Kazuya; Hatanaka, Nobuhiro; Okumura, Kazuyuki
no journal, ,
no abstracts in English