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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
JAEA-Technology-2022-031.pdf:6.57MB
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.
Kawasaki, Kohei; Shinada, Kenta; Okamoto, Naritoshi; Kageyama, Tomio; Eda, Takashi; Okazaki, Hiro; Suzuki, Hiromichi; Yamamoto, Kazuya; Otabe, Jun
JAEA-Technology 2020-025, 80 Pages, 2021/03
JAEA-Technology-2020-025.pdf:3.72MB
Plutonium Fuel Production Facility was built in 1988 for the purpose of mainly producing MOX fuel of the prototype fast breeder reactor MONJU, and large glove boxes were installed for handling unsealed nuclear fuel material remotely. The panels of these glove boxes are made of acrylic, except for those installed after December 2013. For fires inside the glove box, automatic fire extinguishing systems using halides have been introduced since the beginning of construction, but for fires outside the glove box, there have been issues with direct measures for acrylic. Therefore, we have developed a fireproof sheet that mitigates the effect of fire outside the glove box on the panels as much as possible. As a result, fire-retardant sheets have been selected and attached to the glove box panels. We conducted a flammability test of the acrylic plate attached with these fireproof sheets and a usage environment influence test of fireproof sheets, and obtained good results. In addition, we set up a working group in the Plutonium Fuel Development Center in view of reducing external exposure during the work of attaching fireproof sheets, in which we discussed and examined the work procedure, and summarized it in the basic procedure manual.
Yanagibashi, Katsumi; Kanamori, Masashi; Okamoto, Naritoshi
JNC TN8420 2004-002, 109 Pages, 2005/02
JNC-TN8420-2004-002.pdf:9.01MB
On September 30
1999, the criticality accident occurred at JCO's uranium conversion building in Tokai. The accident occurred during reconversion from U
O
to uranium nitrate solution (UNH) with uranium enriched 18.8% and about 60 kgU. JCO contracted with JNC to supply UNH that is fuel material for the experimental fast breeder reactor "JOYO". JNC has contracted with JCO that had started nuclear fuel material processing business following a definite policy of Japanese government and developed "SUMITOMO ADU PROCESS". JNC made the first contract with JCO in 1985 and has made a contact every year. There had never been a problem in their products. JNC inspected products based on contract. JNC discharge our duty as customer inspecting products based on contract. As for safety control, JCO had taken licensing safety review and had been permitted to be "a processing facility". Therefore JNC understood that JCO produced following this license. "The Uranium Processing Plant Criticality Accident Investigation" showed that JCO had been taking a different method from the permit and violating the license. However JNC had never been explained about that and JCO's operation procedures had never described about that. Therefore the Criticality Accident couldn't be avoided. The reports is the revision of former JNC TN8420 2003-003.
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
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.