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Yamamoto, Seishiro*; Odaira, Naoya*; Ito, Daisuke*; Ito, Kei*; Saito, Yasushi*; Imaizumi, Yuya; Matsuba, Kenichi; Kamiyama, Kenji
Konsoryu, 37(1), p.79 - 85, 2023/03
Yamamoto, Seishiro*; Odaira, Naoya*; Ito, Daisuke*; Ito, Kei*; Saito, Yasushi*; Imaizumi, Yuya; Matsuba, Kenichi; Kamiyama, Kenji
Proceedings of 12th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS12) (Internet), 4 Pages, 2022/10
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Ito, Kenji; Kondo, Tetsuo; Nakamura, Yasuyuki; Matsuno, Hiroki; Nagaoki, Yoshihiro; Sakuma, Yuichi
Dekomisshoningu Giho, (63), p.1 - 26, 2022/05
The prototype advanced thermal reactor Fugen entered into the decommissioning phases with the approval of the decommissioning plan in February 2008. The prototype fast breeder reactor Monju entered into the decommissioning stage with the approval of the decommissioning plan in March 2018. In April 2018, the head office of Tsuruga decommissioning demonstration was newly established to oversee the decommissioning operations in Tsuruga area, and decommissioning projects for two unique reactors have progressed safely and steadily.
Ito, Daisuke*; Kurisaki, Tatsuya*; Ito, Kei*; Saito, Yasushi*; Imaizumi, Yuya; Matsuba, Kenichi; Kamiyama, Kenji
Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.6430 - 6439, 2019/08
In core disruptive accident of sodium-cooled fast reactor, cooling of residual fuel debris formed in the reactor core is one of important factors to achieve in-vessel retention of the fuel. To clarify the feasibility of the cooling which is called "in-place cooling", characteristics of gas-liquid two-phase flow in the debris bed must be well understood. Since the debris bed can be formed in a confined flow channel in the core, effect of the channel wall cannot be neglected. Thus, this study aims to clarify the effect of the wall on two-phase flow characteristics in the debris bed, which was simulated as a particle bed packed in a pipe. The pressure drop was measured and compared with results by previous models, and porosity and void fraction distributions were measured by X-ray radiography. Then, the pressure drop evaluation model was modified considering the wall effect, and the applicability of the models was discussed.
Kurisaki, Tatsuya*; Ito, Daisuke*; Ito, Kei*; Saito, Yasushi*; Imaizumi, Yuya; Matsuba, Kenichi; Kamiyama, Kenji
Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 3 Pages, 2018/11
In the evaluation of the in-place cooling which is for the residual core materials in the severe accident of sodium-cooled fast reactors, pressure loss of two-phase flow in debris bed is one of the important factors. Although Lipinski model is already proposed for the pressure loss evaluation, the accuracy would decrease when the porosity is not homogeneous. Thus, experiment to measure the pressure loss in a packed bed of non-homogeneous porosity distribution was conducted, and the Lipinski model was modified dividing the cross section to evaluate the pressure loss in it. As a result, it was confirmed that agreement of the experimental values with the values by modified Lipinski model was better than that with the original Lipinski model.
Ito, Daisuke*; Ito, Kei*; Saito, Yasushi*; Aoyagi, Mitsuhiro; Matsuba, Kenichi; Kamiyama, Kenji
Nuclear Engineering and Design, 334, p.90 - 95, 2018/08
Times Cited Count:9 Percentile:66.49(Nuclear Science & Technology)Two-phase flow through porous media must be well understood to develop a severe accident analysis code not only for light water reactor but also sodium-cooled fast reactor. When a core disruptive accident occurs in sodium-cooled fast reactor, the fuel inside the core become melted and interacts with the coolant. As a result, gas-liquid two-phase flow will be formed in the debris bed, which may have porous nature depending on the cooling process. In such condition, the local porosity and its distribution are very important to characterize two-phase flow field in the porous media. In this study, X-ray radiography was applied to measure the local porosity in the packed bed of spheres. The radial profiles were estimated from the chordal profiles measured by the X-ray method and compared with the previous porosity model. In addition, the void fraction radial profiles were also obtained in air-water two-phase flow.
Ito, Daisuke*; Rivera, M. N.*; Saito, Yasushi*; Aoyagi, Mitsuhiro; Kamiyama, Kenji; Suzuki, Toru*
Proceedings of 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-17) (USB Flash Drive), 10 Pages, 2017/09
Nava, M.*; Ito, Daisuke*; Saito, Yasushi*; Aoyagi, Mitsuhiro; Kamiyama, Kenji; Suzuki, Toru*
Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 5 Pages, 2017/07
Ito, Daisuke*; Nava, M.*; Saito, Yasushi*; Aoyagi, Mitsuhiro; Kamiyama, Kenji; Suzuki, Toru*
Proceedings of 2017 Japan-US Seminar on Two-Phase Flow Dynamics (JUS 2017), 4 Pages, 2017/06
Oyama, Sunao*; Hamamoto, Shimpei; Kaneshiro, Noriyuki*; Nemoto, Takahiro; Sekita, Kenji; Isozaki, Minoru; Emori, Koichi; Ito, Yoshiteru*; Yamamoto, Hideo*; Ota, Yukimaru; et al.
JAEA-Technology 2007-047, 40 Pages, 2007/08
High-Temperature engineering Test Reactor (HTTR) built by Japan Atomic Energy Agency (JAEA) has commonly used reciprocating compressor to extract helium gas and discharge helium gas into primary/secondary coolant helium loop from helium purification system. Rod-seal structure of the compressor is complicated from a prevention coolant leak standpoint. Because of frequently leakage of seal oil in operation, Rod seal structure isn't as reliable as it should be sustainable in the stable condition during long term operation. As a result of investigations, leakage's root is found in that seal were used in a range beyond limit sliding properties of seal material. Therefore a lip of the seal was worn and transformed itself and was not able to sustain a seal function. Endurance test using materials testing facility and verification test using a actual equipment on candidate materials suggest that a seal of fluorine contained resin mixed graphite is potentially feasible material of seal.
Takahashi, Kenji*; Inoue, Kazuhiko; Kato, Asao*; Ito, Kei; Fujita, Takafumi*
Transactions of 18th International Conference on Structural Mechanics in Reactor Technology (SMiRT-18), p.3371 - 3380, 2006/03
We carried out reflection seismic and multi-offset VSP surveys at JNC Shobasama-site to develop the investigation technique in the granite area, and evaluated the applicability of these geophysical methods. As the result of this study, we consider that (a) It is possible to infer the existence of the lower angle fracture zone in the granite by reflection seismic survey and (b) Multi-offset VSP supplements the result of reflection seismic survey and it is possible to infer the distribution of the fracture zone in deeper area in the granite.
Takahashi, Kenji; Kato, Asao*; Ito, Kei; Fushimi, Minoru*; Fujita, Takafumi*; Inoue, Kazuhiko*
Dynamics and Design Conference 2005 (D&D 2005) Koen Rombunshu (CD-ROM), 6 Pages, 2005/09
In order to reduce the cost of plant design and construction, and to enhance the credibility, a study for Three-Dimensional isolation system was permormed. There are two types of isolation system. One is a 3D entire building isolaiton system. The other is a vertical isolation system which is added on the horizontal entire building isolation system. For both systems, outlines of development,requirements of the sytems, process of the verification tests, test results and applicabilities to the fast breeder reactor are mentioned.
Takahashi, Kenji; Inoue, Kazuhiko; Ito, Kei; Fujita, Takafumi*
Proceedings of 2005 ASME/JSME Pressure Vessels and Piping Division Conference (PVP 2005), 8 Pages, 2005/07
We carried out reflection seismic and multi-offset VSP surveys at JNC Shobasama-site to develop the investigation technique in the granite area, and evaluated the applicability of these geophysical methods.As the result of this study, we consider that a) It is possible to infer the existence of the lower angle fracture zone in the granite by reflection seismic survey and b) Multi-offset VSP supplements the result of reflection seismic survey and it is possible to infer the distribution of the fracture zone in deeper area in the granite.
Ito, Kenji
Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 0 Pages, 2003/00
None
Koizumi, Koichi; Nakahira, Masataka; Oka, Kiyoshi; *; Takahashi, Hiroyuki*; Tada, Eisuke; Ioki, Kimihiro*; Johnson, G.*; Onozuka, Masanori*; Y.Utin*; et al.
Fusion Technology, 34(3), p.586 - 590, 1998/11
no abstracts in English
Koizumi, Koichi; Nakahira, Masataka; *; Takahashi, Hiroyuki*; Tada, Eisuke; Ioki, Kimihiro*; Johnson, G.*; Onozuka, Masanori*; Y.Utin*; Sonnazzaro, G.*; et al.
Proceedings of 17th IEEE/NPSS Symposium Fusion Engineering (SOFE'97), 2, p.933 - 936, 1998/00
no abstracts in English
Ito, Kazuhiro; Yamamoto, Masaya; Maeda, Koji; Akasaka, Naoaki; Harada, Akio; Konashi, Kenji*
no journal, ,
As part of "Development of Hydride Neutron Absorber for Fast Reactor", a series of neutron irradiation experiment with in HfH, (Gd+ZR)H and stainless steel specimens was performed in experimental fast reactor Joyo. Here, the stainless steel specimens were coated by oxide film to simulate a cladding tube. In this report, the irradiation examination plan and a result were summarized.
Onizawa, Takahiro; Ito, Kenji; Osaki, Toshiyuki
no journal, ,
In the secondary sodium cooling system equipment of Monju, the leakage was ended at the early stage when sodium leaked, and the remodeling construction to control the influence on equipment by the sodium combustion etc. further more were done. These are the addition of drain piping, the enlargement of drain piping and the batch operation of emergency drain valve etc.. In the modification function tests of secondary sodium cooling system, these function and performance, etc. were confirmed.