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Sakakibara, Hiroshi; Aoki, Nobuhiro; Muto, Masahiro; Otabe, Jun; Takahashi, Kenji*; Fujita, Naoyuki*; Hiyama, Kazuhiko*; Suzuki, Hirokazu*; Kamogawa, Toshiyuki*; Yokosuka, Toru*; et al.
JAEA-Technology 2020-020, 73 Pages, 2021/03
JAEA-Technology-2020-020.pdf:8.26MB
The decommissioning is currently in progress at the prototype fast breeder reactor Monju. Fuel assemblies will be taken out of its core for the first step of the great task. Fuel assemblies stand on their own spike plugged into a socket on the core support plate and support with adjacent assemblies through their housing pads each other, resulting in steady core structure. For this reason, some substitutive assemblies are necessary for the purpose of discharging the fuel assemblies of the core. Monju side commissioned, therefore, Plutonium Fuel Development Center to manufacture the substitutive assemblies and the Center accepted it. This report gives descriptions of design, manufacture, and shipment in regard to the substitutive assemblies.
Takahashi, Saburo; Kikuno, Hiroshi; Shiromo, Hideo; Kuba, Meiji; Abe, Tomoyuki; Takeda, Seiichiro
Proceedings of 16th Pacific Basin Nuclear Conference (PBNC-16) (CD-ROM), 6 Pages, 2008/10
Japan Atomic Energy Agency (JAEA) has been accumulating various experience and knowledge on development of MOX fuel technologies for more than 40 years since 1966. Plutonium Fuel Production Facility (PFPF) has introduced a fully automated and remote operation in 1988 as a pioneer in the world, based on the operational and technical experience obtained in the existing facilities. The PFPF has fabricated MOX fuel assemblies for a fast reactor "JOYO" and a fast breeder reactor "MONJU" so far. Through MOX fuel fabrication for JOYO and MONJU, many operational experiences such as a hold-up material problem have been gained. Based on the experiences, process equipments have been newly developed and a process technology has been improved. As the results, fully automated and remote fabrication technologies including easy contact maintenance of process equipments for FBR MOX fuel have been demonstrated in the PFPF on a large scale.
Kikuno, Hiroshi
no journal, ,
no abstracts in English
Okada, Toyofumi; Shibanuma, Tomohiro; Honda, Fumiya; Komeno, Akira; Kikuno, Hiroshi
no journal, ,
Am is generated by beta-decay of Pu. In the case of treating MOX, it is important for shielding about 60keV gamma-ray emitted by Am. Also getting dose rate data of MOX containing Am is valuable. In this work, we measured gamma-ray dose rate from MOX containing Am by changing thickness of shielding materials and range between MOX and measuring instruments. Also we confirmed that calculating analysis is useful for evaluation of shielding material's performance.
Sakakibara, Hiroshi; Aoki, Nobuhiro; Muto, Masahiro; Otabe, Jun; Takahashi, Kenji*; Fujita, Naoyuki*; Hiyama, Kazuhiko*; Suzuki, Hirokazu*; Kamogawa, Toshiyuki*; Yokosuka, Toru*; et al.
no journal, ,
no abstracts in English
Shioya, Satoshi; Nakagawa, Takahiro; Yamazaki, Takumi; Tachihara, Joji; Shuji, Yoshiyuki; Kikuno, Hiroshi
no journal, ,
In order to reduce the workload and improve the safety (i.e., prevention of internal exposure) of workers at Plutonium handling facilities, etc., JAEA has introduced a new Powered Air Purifying Respirator (PAPR) full-face mask as respiratory protective equipment. In introducing this mask, we conducted a leakage test in correspondence with Japanese Industrial Standards (JIS). In the leakage test, an examinee person wearing the mask entered an airlock and performed a prescribed action (e.g., stepping up and down on a stepladder, etc.) while the number concentration of NaCl test particles in/out of the mask was measured. Leakage rates were calculated for the results of 10 examinees. The test results showed that the leakage rate of this mask was 
0.01% (corresponding to the protection factor of 
10000) even when the electric fan was stopped, confirming that the mask remained high protection capability.
Okada, Toyofumi; Horii, Yuta; Tsubota, Yoichi; Komeno, Akira; Kikuno, Hiroshi
no journal, ,
In this research, purpose is getting gamma dose rate from MOX and PuO
containing Americium and evaluating exposure dose by calculation code. One of reasons of difference between measurement value and calculation value is scattering ray from inside of globe box panel because MOX is handled inside of globe box. Therefore, we improve measuring method (changing MOX position, applying shadow shield method) and get new data which difference between measurement value and calculation value (using ANISN) is smaller than before. Furthermore, we confirm that it can be available to apply PHITS for evaluating exposure dose.