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Okita, Shoichiro; Aoki, Takeshi; Fukaya, Yuji; Tachibana, Yukio
Proceedings of 31st International Conference on Nuclear Engineering (ICONE31) (Internet), 5 Pages, 2024/11
Shimokita, Keisuke*; Yamamoto, Katsuhiro*; Miyata, Noboru*; Shibata, Motoki*; Nakanishi, Yohei*; Arakawa, Masato*; Takenaka, Mikihito*; Kida, Takumitsu*; Tokumitsu, Katsuhisa*; Tanaka, Ryo*; et al.
Langmuir, 40(30), p.15758 - 15766, 2024/07
Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; Noguchi, Hiroki; et al.
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 6 Pages, 2023/05
Nomoto, Yasunobu; Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; et al.
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 7 Pages, 2023/05
Tamura, Fumihiko; Omori, Chihiro*; Yoshii, Masahito*; Tomizawa, Masahito*; Toyama, Takeshi*; Sugiyama, Yasuyuki*; Hasegawa, Katsushi*; Kobayashi, Aine*; Okita, Hidefumi
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.175 - 178, 2023/01
J-PARC MR delivers high intensity proton beams to the neutrino experiment. Eight bunches with high peak currents are extracted from the MR by the extraction kicker, therefore the neutrino beam has the similar structure. Intermediate Water Cherenkov Detector (IWCD) will be installed for the future experiments and the IWCD requires a time structure with low peaks. We consider bunch manipulation at flattop of the MR for reducing the peak current. It should be quickly done to avoid the significant loss of the beam power. The beam gap for the kicker rise time must be kept. We propose a non-adiabatic bunch manipulation using the multiharmonic rf voltage. The longitudinal impedance in the MR can affect the beam stability. The feasibility of the manipulation is discussed by using the longitudinal simulations.
Aoki, Takeshi; Shimizu, Atsushi; Iigaki, Kazuhiko; Okita, Shoichiro; Hasegawa, Takeshi; Mizuta, Naoki; Sato, Hiroyuki; Sakaba, Nariaki
JAEA-Review 2022-016, 193 Pages, 2022/08
Aiming to realize a massive, cost-effective and carbon-free hydrogen production technology utilizing a high temperature gas cooled reactor (HTGR), Japan Atomic Energy Agency (JAEA) is planning a HTTR heat application test producing hydrogen with High Temperature Engineering Test Reactor (HTTR) achieved 950C of the highest reactor outlet coolant temperature in the world. In the HTTR heat application test, it is required to establish its safety design realizing highly safe connection of a HTGR and a hydrogen production plant by the Nuclear Regulation Authority to obtain the permission of changes to reactor installation. However, installation of a system connecting the hydrogen production plant and a nuclear reactor, and its safety design has not been conducted so far in conventional nuclear power plant including HTTR in the world. A special committee on the HTTR heat application test, established under the HTGR Research and Development Center, considered a safety design philosophy for the HTTR heat application test based on an authorized safety design of HTTR in terms of conformity to the New Regulatory Requirements taking into account new considerable events as a result of the plant modification and connection of the hydrogen production plant. This report provides materials of the special committee such as technical reports, comments provided from committee members, response from JAEA for the comments and minutes of the committee.
Aoki, Takeshi; Shimizu, Atsushi; Iigaki, Kazuhiko; Okita, Shoichiro; Hasegawa, Takeshi; Mizuta, Naoki; Sato, Hiroyuki; Sakaba, Nariaki
JAEA-Technology 2022-011, 60 Pages, 2022/07
Japan Atomic Energy Agency is planning a High Temperature Engineering Test Reactor (HTTR) heat application test producing hydrogen with the HTTR which achieved the highest reactor outlet coolant temperature of 950C in the world to realize a massive, cost-effective and carbon-free hydrogen production technology utilizing a high temperature gas cooled reactor (HTGR). In the HTTR heat application test, it is required to establish its safety design for coupling a hydrogen production plant to HTGR through the licensing by the Nuclear Regulation Authority (NRA). A draft of a safety design philosophy for the HTTR heat application test facility was considered taking into account postulated events due to the plant modification and coupling of the hydrogen production plant based on the HTTR safety design which was authorized through the safety review of the NRA against New Regulatory Requirements. The safety design philosophy was examined to apply proven conventional chemical plant standards to the hydrogen production plant for ensuring public safety against disasters caused by high pressure gases. This report presents a result of a consideration on safety design philosophies regarding the reasonability and condition to apply the High Pressure Gas Safety Act for the hydrogen production plant, safety classifications, seismic design classification, identification of important safety system.
Kofuji, Hirohide; Yano, Tetsuji*; Myochin, Munetaka; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*
Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 6 Pages, 2014/07
For the research and development of the nuclear waste disposal concept suitable to the pyrochemical processing system and its performance evaluation, the iron-phosphate glass is examined as an alternative waste form for high level waste generated from electro-refining process. In order to enhance the waste element content in the glass matrix and improve the durability of the waste form, optimization experiments of the glass composition were carried out and the effect of additional other transition metal oxides was found out in this study.
Kofuji, Hirohide; Yano, Tetsuji*; Myochin, Munetaka; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*
Procedia Chemistry, 7, p.764 - 771, 2012/00
Times Cited Count:14 Percentile:95.27(Chemistry, Analytical)As a part of the research and development for the nuclear waste disposal concept suitable to the advanced fuel cycle systems and its performance evaluation, the iron-phosphate glass is examined as an alternative waste form for high level waste generated from pyrochemical reprocessing. In order to enhance the waste element content in the glass matrix and improve the durability of the waste form, optimization experiments of glass composition were carried out and the effect of additional other transition metal oxides was found out in this study.
Okita, Shoichiro; Aoki, Takeshi; Sato, Hiroyuki; Aihara, Jun; Ohashi, Hirofumi
no journal, ,
no abstracts in English
Sato, Hiroyuki; Aoki, Takeshi; Okita, Shoichiro; Hasegawa, Takeshi; Shimizu, Atsushi; Iigaki, Kazuhiko; Sakaba, Nariaki
no journal, ,
no abstracts in English
Amamoto, Ippei; Fukushima, Mineo; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*; Utsunomiya, Kazuhiro*; Yano, Tetsuji*
no journal, ,
no abstracts in English
Morita, Keisuke; Shimizu, Atsushi; Noguchi, Hiroki; Aoki, Takeshi; Okita, Shoichiro; Mizuta, Naoki; Ishii, Katsunori; Iigaki, Kazuhiko; Sato, Hiroyuki; Sakaba, Nariaki
no journal, ,
no abstracts in English
Nomoto, Yasunobu; Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; et al.
no journal, ,
no abstracts in English
Kofuji, Hirohide; Yano, Tetsuji*; Myochin, Munetaka; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*
no journal, ,
no abstracts in English
Kofuji, Hirohide; Yano, Tetsuji*; Myochin, Munetaka; Okita, Takeshi*; Miyamoto, Shinya*
no journal, ,
As a part of the research and development for the nuclear waste disposal concept suitable to the advanced fuel cycle systems and its performance evaluation, the iron-phosphate glass is examined as an alternative waste form for high level waste generated from pyrochemical reprocessing. In order to enhance the waste element content in the glass matrix and improve the durability of the waste form, optimization experiments of glass composition were carried out in this study.
Kofuji, Hirohide; Amamoto, Ippei; Matsuyama, Kanae*; Okita, Takeshi*; Myochin, Munetaka; Yano, Tetsuji*
no journal, ,
The iron phosphate glass has been investigated for the high level waste originated from the pyrochemical reprocessing. The results of the optimization of glass composition were introduced in this report for high FP loading and improvement of chemical durability of the waste form.
Yano, Tetsuji*; Akagi, Naoto*; Shibata, Shuichi*; Okita, Takeshi*; Matsuyama, Kanae*; Miyamoto, Shinya*; Amamoto, Ippei; Kofuji, Hirohide
no journal, ,
Surface structures of iron phosphate glasses (IPG) are investigated in order to know the origin of the high chemical durability using X-ray photoelectron spectroscopy. In this study, several IPG samples in which a part of iron oxide are replaced by other transition metal oxides are prepared and subjected to the chemical durability test. Surface structures are investigated before and after the durability test and the information on the structural changes are obtained.
Sato, Hiroyuki; Kimura, Shigeru; Yamagishi, Isao; Ikeda, Akira*; Okita, Takeshi*
no journal, ,
As a part of consideration for long-term storage of a spent zeolite adsorption vessel in the Fukushima Daiichi Nuclear Power Plant, experiment of non-radioactive Cesium adsorbed distribution in vessel was carried out to estimate inner environment (radiation and decay heat by radioactive Cesium) effected to corrosion in SARRY, using actual sized model of SARRY adsorption vessel.
Sato, Hiroyuki; Terada, Atsuhiko; Kato, Chiaki; Yamagishi, Isao; Ikeda, Akira*; Okita, Takeshi*
no journal, ,
As a part of consideration for long-term storage of a spent zeolite adsorption vessel in the Fukushima No.1 nuclear power plant, experiment flashing salt component (5,000 ppm in chloride ion) in vessel was carried out using actual sized model of SARRY adsorption vessel.