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Tsai, T.-H.; Sasaki, Shinji; Maeda, Koji
Journal of Nuclear Science and Technology, 60(6), p.715 - 723, 2023/06
Times Cited Count:1 Percentile:27.23(Nuclear Science & Technology)Takabe, Yugo; Otsuka, Noriaki; Fuyushima, Takumi; Sayato, Natsuki; Inoue, Shuichi; Morita, Hisashi; Jaroszewicz, J.*; Migdal, M.*; Onuma, Yuichi; Tobita, Masahiro*; et al.
JAEA-Technology 2022-040, 45 Pages, 2023/03
Because of the decommission of the Japan Materials Testing Reactor (JMTR), the domestic neutron irradiation facility, which had played a central role in the development of innovative nuclear reactors and the development of technologies to further improve the safety, reliability, and efficiency of light water reactors, was lost. Therefore, it has become difficult to pass on the operation techniques of the irradiation test reactors and irradiation technologies, and to train human resources. In order to cope with these issues, we conducted a study on the implementation of irradiation tests using overseas reactors as neutron irradiation sites as an alternative method. Based on the "Arrangement between the National Centre for Nuclear Research and the Japan Atomic Energy Agency for Cooperation in Research and Development on Testing Reactor," the feasibility of conducting an irradiation test at the MARIA reactor (30 MW) owned by the National Centre for Nuclear Research (NCBJ) using the temperature control system, which is one of the JMTR irradiation technologies, was examined. As a result, it was found that the irradiation test was possible by modifying the ready-made capsule manufactured in accordance with the design and manufacturing standards of the JMTR. After the modification, a penetration test, an insulation continuity test, and an operation test in the range of room temperature to 300C, which is the operating temperature of the capsule, were conducted and favorable results were obtained. We have completed the preparations prior to transport to the MARIA reactor.
Mineo, Hideaki
Nihon Genshiryoku Gakkai-Shi ATOMO, 64(11), p.617 - 621, 2022/11
In December 2016 Decisions were made by the Government on the Fast Breeder Prototype Reactor "Monju", which were decommissioning of the reactor and installation of a new research reactor at the Monju site. After the decisions, MEXT started research to list reactor candidates suitable for the site. Among the candidates, medium power reactor type of which thermal output less than 10,000 kW was chosen to utilize neutron beams. Then, from 2020, MEXT launched an entrusted business and adopted JAEA, Kyoto University and University of Fukui as the core institutions of the business to carry out the conceptual design. This paper describes the system to proceed the conceptual design and to examine the utilization management of the new research reactor and also shows their status.
Lu, K.; Takamizawa, Hisashi; Katsuyama, Jinya; Li, Y.
International Journal of Pressure Vessels and Piping, 199, p.104706_1 - 104706_13, 2022/10
Times Cited Count:3 Percentile:56.32(Engineering, Multidisciplinary)Jensen, C. B.*; Wachs, D. M.*; Woolstenhulme, N. E.*; Ozawa, Takayuki; Hirooka, Shun; Kato, Masato
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22) (Internet), 9 Pages, 2022/04
Uwaba, Tomoyuki; Nemoto, Junichi*; Ito, Masahiro*; Ishitani, Ikuo*; Doda, Norihiro; Tanaka, Masaaki; Otsuka, Satoshi
Nuclear Technology, 207(8), p.1280 - 1289, 2021/08
Times Cited Count:3 Percentile:34.17(Nuclear Science & Technology)Computer codes for irradiation behavior analysis of a fuel pin and a fuel pin bundle and for coolant thermal hydraulics analysis were coupled into an integrated code system. In the system, each code provides data required by other codes and the analyzed results are shared among them. The system allows for the synthesizing of analyses of thermal, chemical and mechanical behaviors in a fuel subassembly under irradiation. A test analysis was made for a fuel subassembly containing a mixed oxide fuel pin bundle irradiated in a fast reactor. The results of the analysis were presented with transverse cross-sectional images of the fuel subassembly and three-dimensional images of a fuel pin and fuel pin bundle models. For detailed evaluation, various irradiation behaviors of all fuel pins in the subassembly were analyzed and correlated with irradiation conditions.
Iwata, Keiko; Hata, Kuniki; Tobita, Toru; Hirota, Takatoshi*; Takamizawa, Hisashi; Chimi, Yasuhiro; Nishiyama, Yutaka
Proceedings of ASME 2021 Pressure Vessels and Piping Conference (PVP 2021) (Internet), 7 Pages, 2021/07
Lu, K.; Katsuyama, Jinya; Li, Y.; Yoshimura, Shinobu*
Journal of Pressure Vessel Technology, 143(2), p.021505_1 - 021505_8, 2021/04
Times Cited Count:1 Percentile:9.69(Engineering, Mechanical)Kenzhina, I.*; Ishitsuka, Etsuo; Ho, H. Q.; Sakamoto, Naoki*; Okumura, Keisuke; Takemoto, Noriyuki; Chikhray, Y.*
Fusion Engineering and Design, 164, p.112181_1 - 112181_5, 2021/03
Tritium release into the primary coolant during operation of the JMTR (Japan Materials Testing Reactor) and the JRR-3M (Japan Research Reactor-3M) had been studied. It is found that the recoil release by Li(n
,
)
H reaction, which comes from a chain reaction of beryllium neutron reflectors, is dominant. To prevent tritium recoil release, the surface area of beryllium neutron reflectors needs to be minimum in the core design and/or be shielded with other material. In this paper, as the feasibility study of the tritium recoil barrier for the beryllium neutron reflectors, various materials such as Al, Ti, V, Ni, and Zr were evaluated from the viewpoint of the thickness of barriers, activities after long-term operations, and effects on the reactivities. From the results of evaluations, Al would be a suitable candidate as the tritium recoil barrier for the beryllium neutron reflectors.
Kenzhina, I.*; Ishitsuka, Etsuo; Okumura, Keisuke; Ho, H. Q.; Takemoto, Noriyuki; Chikhray, Y.*
Journal of Nuclear Science and Technology, 58(1), p.1 - 8, 2021/01
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)The sources and mechanisms for the tritium release into the primary coolant in the JMTR and the JRR-3M containing beryllium reflectors are evaluated. It is found that the recoil release from chain reaction of Be is dominant and its calculation results agree well with trends derived from the measured variation of tritium concentration in the primary coolant. It also indicates that the simple calculation method used in this study for the tritium recoil release from the beryllium reflectors can be utilized for an estimation of the tritium release into the primary coolant for a research and testing reactors containing beryllium reflectors.
Amaya, Masaki; Kakiuchi, Kazuo; Mihara, Takeshi
Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.1048 - 1056, 2019/09
Ito, Chikara; Naito, Hiroyuki; Ishikawa, Takashi; Ito, Keisuke; Wakaida, Ikuo
JPS Conference Proceedings (Internet), 24, p.011038_1 - 011038_6, 2019/01
A high-radiation resistant optical fiber has been developed in order to investigate the interiors of the reactor pressure vessels and the primary containment vessels at the Fukushima Daiichi Nuclear Power Station. The tentative dose rate in the reactor pressure vessels is assumed to be up to 1 kGy/h. We developed a radiation resistant optical fiber consisting of a 1000 ppm hydroxyl doped pure silica core and 4 % fluorine doped pure silica cladding. We attempted to apply the optical fiber to remote imaging technique by means of fiberscope. The number of core image fibers was increased from 2000 to 22000 for practical use. The transmissive rate of infrared images was not affected after irradiation of 1 MGy. No change in the spatial resolution of the view scope by means of image fiber was noted between pre- and post-irradiation. We confirmed the applicability of the probing system, which consists of a view scope using radiation-resistant optical fibers.
Tobita, Toru; Nishiyama, Yutaka; Onizawa, Kunio
JAEA-Data/Code 2018-013, 60 Pages, 2018/11
Mechanical properties of materials including fracture toughness are extremely important for evaluating the structural integrity of reactor pressure vessels (RPVs). In this report, the published data of mechanical properties of nuclear RPVs steels, including neutron irradiated materials, acquired by the Japan Atomic Energy Agency (JAEA), specifically tensile test data, Charpy impact test data, drop-weight test data, and fracture toughness test data, are summarized. There are five types of RPVs steels with different toughness levels equivalent to JIS SQV2A (ASTM A533B Class 1) containing impurities in the range corresponding to the early plant to the latest plant. In addition to the base material of RPVs, the mechanical property data of the two types of stainless overlay cladding materials used as the lining of the RPV are summarized as well. These mechanical property data are organized graphically for each material and listed in tabular form to facilitate easy utilization of data.
Nishimura, Arata*; Muroga, Takeo*; Takeuchi, Takao*; Nishitani, Takeo; Morioka, Atsuhiko
Fusion Engineering and Design, 81(8-14), p.1675 - 1681, 2006/02
Times Cited Count:3 Percentile:24.07(Nuclear Science & Technology)In a fusion reactor plant, a neutral beam injector (NBI) will be operated for a long time, and it will allow neutron streaming from NBI ports to outside of the plasma vacuum vessel. It requires the superconducting magnet to develop nuclear technology to produce stable magnetic field and to reduce activation of the magnet components. In this report, the back ground of the necessity and the contents of the nuclear technology of the superconducting magnets for fusion application are discussed and some typical investigation results are presented, which are the neutron irradiation effect on NbSn wire, the development of low activation superconducting wire, and the design concept to reduce nuclear heating and nuclear transformation by streaming. In addition, recent activities in high energy particle physics are introduced and potential ripple effect of the technology of the superconducting magnets is described briefly.
Hegeman, J. B. J.*; Van der Laan, J. G.*; Kawamura, Hiroshi; Mslang, A.*; Kupriyanov, I.*; Uchida, Munenori*; Hayashi, Kimio
Fusion Engineering and Design, 75-79, p.769 - 773, 2005/11
Times Cited Count:26 Percentile:83.94(Nuclear Science & Technology)no abstracts in English
Fujii, Kimio
JAERI-Tech 2005-048, 108 Pages, 2005/09
The graphite-moderated power reactor was shut down in 1998 and its decommissioning program is being planned. Various graphites are used in the core of magnox-type reactors and HTTR as core-support structural materials and moderating materials of fast neutrons. For the nuclear graphite disposal, it is necessary to determine especially the treatment of long-lived nuclides, such as C which are generated in the graphite components during reactor operation. As a research, which solves the problem of the
C concentration, the cooperative research is concluded between JAERI and Japan Nuclear Power Corp. in 1999, and the research for the basic data acquisition has been advanced up to the present. To find the optimum conditions for
C reduction, basic data on oxidation reaction and the structure of graphite materials are indispensable. In the present experiment, we measure the air oxidation characteristics in the temperature range 450
800
C in Quality1 graphite and IG-110 graphite. Changes in pore diameter and pore size distribution due to air oxidation are discussed.
Research Reactor Utilization Division
JAERI-Review 2005-034, 450 Pages, 2005/09
no abstracts in English
Nakamichi, Masaru*; Kawamura, Hiroshi
JAERI-Research 2005-015, 35 Pages, 2005/06
no abstracts in English
Department of JMTR
JAERI-Review 2004-029, 100 Pages, 2005/01
no abstracts in English
Takahashi, Toshiyuki; Research Reactor Utilization Division
JAERI-Review 2004-016, 542 Pages, 2004/08
no abstracts in English