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Chikazawa, Yoshitaka; Kato, Atsushi; Hirata, Shingo*; Obata, Hiroyuki*
Journal of Nuclear Science and Technology, 51(6), p.798 - 808, 2014/06
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)JSFR is going to adopt an advanced fuel handling system. As for ex-vessel spent fuel handling, a transfer pot with two fuel subassembly positions has been developed so as to shorten refueling period increasing plant availability. The pot is required to provide sufficient cooling capability in case of transportation malfunction. To evaluate cooling capacity of the transfer pot, a mockup pot has been fabricated and heat transfer experiments have been conducted on the mockup pot.
Kato, Atsushi; Chikazawa, Yoshitaka; Uto, Nariaki; Hirata, Shingo; Obata, Hiroyuki*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR 2009) (CD-ROM), 12 Pages, 2012/00
A basic feasibility of the helium gas cask has been evaluated by thermal analyses. There have been conducted two analyses: whole cask and detail inside subassembly analyses. The detail inside subassembly analysis has shown that the temperature distribution is mainly governed by thermal conductivity and natural convection of coolant helium hardly contributes heat removal. In the case of a cask with five subassemblies with 2.2 kW decay heat per each, the maximum cladding temperature is evaluated to be 361 
C satisfying cladding temperature limit of 395 C. Those results have shown the basic feasibility of the helium gas fresh fuel shipping cask.
Hirata, Shingo; Chikazawa, Yoshitaka; Kato, Atsushi; Uto, Nariaki; Obata, Hiroyuki*; Kotake, Shoji*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR 2009) (CD-ROM), 10 Pages, 2012/00
In Fast Reactor Cycle Technology Development (FaCT) project, Japan Sodium-cooled Fast Reactor (JSFR) is going to adopt an advanced fuel handling system. As for ex-vessel spent fuel handling, a pot which contains two fuel subassemblies simultaneously and is applicable size to compact reactor vessel, has been developing so as to shorten a refueling period leading to an improvement of plant availability. The pot is required to provide sufficient cooling capability even in case of transportation malfunction during transportation of spent fuel subassemblies with high decay heat. In the present study, experimental and analytical studies to evaluate the cooling capacity of the pot are summarized.
Kato, Atsushi; Hirata, Shingo; Chikazawa, Yoshitaka; Uto, Nariaki; Obata, Hiroyuki*; Kotake, Shoji*; Uzawa, Masayuki*
Proceedings of 2010 International Congress on Advances in Nuclear Power Plants (ICAPP '10) (CD-ROM), p.692 - 699, 2010/06
In the JSFR design, a single rotating plug and an upper inner structure (UIS) with a vertically penetrating slit are proposed, so that the fuel handling machine (FHM) can access any subassembly by horizontal movement of the FHM arm in the slit space. As a result of a full-scale mockup test, excellent performance in normal operation has been shown. In this study, from the viewpoint of achieving reliability of the pantograph type FHM, behavior of the FHM mockup have been investigated under abnormal conditions.
Kato, Atsushi; Hirata, Shingo; Chikazawa, Yoshitaka; Uto, Nariaki; Obata, Hiroyuki; Kotake, Shoji
Proceedings of 2009 International Congress on Advances in Nuclear Power Plants (ICAPP '09) (CD-ROM), p.9281_1 - 9281_6, 2009/05
One of the most important challenges to commercialize a Fast Reactor is to increase economic competitiveness. For that purpose, Japan Sodium cooled Fast Reactor (hereafter JSFR) aims to simplify the plant system and reduce the raw and processed material by adopting innovative technologies. In the JSFR design, a single rotating plug and a reactor upper inner structure (hereafter UIS) with a vertically penetrating slit are proposed, so that the fuel handling machine (hereafter FHM) can access any subassembly by horizontal movement of the FHM arm in the slit space. The feature of this FHM enables no need for the UIS removal when the rotational plug moves round above the core, which can achieve a compact reactor vessel to enhance the economic competitiveness. We fabricated the full scale FHM test equipment to perform comprehensive tests in the air for demonstrating the feasibility of the key characteristics of this FHM concept.
Kato, Atsushi; Chikazawa, Yoshitaka; Hirata, Shingo; Uto, Nariaki; Kotake, Shoji*; Obata, Hiroyuki*
no journal, ,
In JSFR development, we have fabricated the mock-up of the fuel handling machine to verify the basic feasibility in the air that achieve the compact reactor vessel.
Chikazawa, Yoshitaka; Hirata, Shingo; Kato, Atsushi; Obata, Hiroyuki*
no journal, ,
In commercialized sodium cooled fast reactor development, minor-actinide bearing fuel is adopted to reduce environmental burden. A new shipping cask with certain shielding and cooling capacity is required to transport fresh subassemblies of minor-actinide bearing fuel. In this paper, a helium gas cask has been selected as a fresh fuel shipping cask, since sodium cooled fast reactor fresh fuel refrains to contact with water before core loading. Heat transfer analyses have been conducted to evaluate feasibility of the helium cask as a minor-actinide fresh fuel shipping cask.
Obata, Hiroyuki*; Chikazawa, Yoshitaka; Kato, Atsushi; Hirata, Shingo
no journal, ,
In the FaCT project, a dry spent fuel cleaning system has been investigated as one of components in commercialized reactor fuel handling system. In this study, cleaning experiments using a mockup fuel subassembly has been conducted to evaluate feasibility of the dry spent fuel cleaning system.
Na and 
Be depositions in Tsuruga cityYoshida, Keisuke; Kato, Shingo; Inoue, Mutsuo*; Ishizuka, Akihiro; Okuyama, Shinichi
no journal, ,
Na is observed for environmental monitoring of Monju fast breeder reactor because Monju reactor contains Na in primary coolant. But Na is produced in upper atmosphere, therefore, Na is detected in assembled deposition sample. To increase accuracy of environmental monitoring, it is necessary to understand transport and supply process of Na and Be depositions from high latitude region where a lot of Na is produced. We collect deposition samples at Tsuruga city to measure Na and collect Be deposition data in 5 sites in Fukui prefecture and Ishikawa prefecture. Because Na and Be shows good correlation, Na have same behavior with Be. Be deposition is maximum at Kanazawa city and minimum at Shika town, but Be deposition is maximum in Winter season at all sites. Be deposition and precipitation shows correlation. From the above, Winter monsoon transport Be and Na from high latitude region and precipitation provide these nuclides to ground surface at Tsuruga city. The deference of Be deposition in Winter season is likely owing to height of mountain and distance of sampling sites.
Kato, Shingo; Ishizuka, Akihiro; Okuyama, Shinichi; Nozaki, Tatsuo; Hayashi, Gaku*; Yasuda, Nakahiro*; Torii, Tatsuo*; Ando, Takasuke*
no journal, ,
no abstracts in English
Kato, Shingo; Yoshida, Keisuke; Inoue, Mutsuo*; Yamashita, Masahiro; Okuyama, Shinichi; Ishimori, Yuu
no journal, ,
no abstracts in English
Be depositions in Hokuriku, JapanYoshida, Keisuke; Kato, Shingo; Uchida, Kengo*; Yamashita, Masahiro; Okuyama, Shinichi; Inoue, Mutsuo*
no journal, ,
In winter, Be deposition profile shows wide variation in Hokuriku region. Temporal and regional variations of Be deposition data during 30 years (Apr. 1991 to Mar. 2021) were analyzed and material transport mechanisms from arctic region were studied. Due to pressure pattern around Japan in winter and inhomogeneous precipitation in Hokuriku region caused by topography, characteristic seasonal variation was found and highest Be deposition was observed in mountainous area in Kanazawa City. In addition, the period of high Be deposition observed approximately agreed with that of minimum sunspot number or maximum precipitation. Therefore, sunspot number and precipitation affect temporal variations of Be deposition.
Hayashi, Gaku*; Torii, Tatsuo*; Ishizuka, Akihiro; Okuyama, Shinichi; Kato, Shingo; Nozaki, Tatsuo; Yasuda, Nakahiro*
no journal, ,
no abstracts in English
