Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Fuwa, Yasuhiro; Hattori, Ayaka*; Ito, Hayato*; Iwashita, Yoshihisa*; Katayama, Ryo*; Kubo, Takayuki*; Saeki, Takayuki*
Proceedings of 22nd Annual Meeting of Particle Accelerator Society of Japan (Internet), p.353 - 355, 2026/03
no abstracts in English
Nagasumi, Satoru; Hasegawa, Toshinari; Nakagawa, Shigeaki; Kubo, Shinji; Iigaki, Kazuhiko; Shinohara, Masanori; Saikusa, Akio; Nojiri, Naoki; Saito, Kenji; Furusawa, Takayuki; et al.
JAEA-Research 2025-005, 23 Pages, 2025/07
JAEA-Research-2025-005.pdf:2.68MB
A safety demonstration test under abnormal operating conditions using the HTTR (High Temperature Engineering Test Reactor) was conducted to demonstrate safety features of the HTGRs (High Temperature Gas-cooled Reactors). Under a simulation of a control rod shutdown failure, all primary helium gas circulators were intentionally stopped during a steady-state operation at 100% reactor thermal power (30 MW), temporal changes of the reactor power and temperatures around the reactor pressure vessel (RPV) were obtained after the complete loss of forced heat removal from the reactor core. After the event (primary coolant flow stopped), the reactor power quickly decreased due to the negative reactivity feedback associated with the core temperature rise, and then the reactor power spontaneously shifted to a stable state of low power (about 1.2%) even after a recriticality. Heat dissipation from RPV surface to a surrounding vessel cooling system (water-cooled panels) ensured the amount of heat removal required to maintain the reactor temperature constant in the low power state. In this way, the transition from the event occurrence to the stable and safety state, i.e., inherent safety features of HTGRs, were demonstrated in the case of core forced cooling loss without active shutdown operations.
Saito, Takumi*; Motokawa, Ryuhei; Okubo, Takahiro*; Miura, Daisuke*; Kumada, Takayuki
Environmental Science & Technology, 57(26), p.9802 - 9810, 2023/07
Times Cited Count：4 Percentile：22.62(Engineering, Environmental)Mamiya, Hiroaki*; Oba, Yojiro; Hiroi, Kosuke; Miyatake, Takayuki*; Gautam, R.*; Sepehri-Amin, H.*; Okubo, Tadakatsu*
IEEE Magnetics Letters, 14, p.7100105_1 - 7100105_5, 2023/02
Times Cited Count：2 Percentile：15.68(Engineering, Electrical & Electronic)Takano, Kazuya; Oki, Shigeo; Ozawa, Takayuki; Yamano, Hidemasa; Kubo, Shigenobu; Ogura, Masashi*; Yamada, Yumi*; Koyama, Kazuya*; Kurita, Koichi*; Costes, L.*; et al.
EPJ Nuclear Sciences & Technologies (Internet), 8, p.35_1 - 35_9, 2022/12
The France and Japan teams have carried out collaborative works to have common technical views regarding a sodium-cooled fast reactor concept. Japan has studied the feasibility of an enhanced high burnup low-void effect (CFV) core and fuel using oxide dispersion-strengthened steel cladding in ASTRID 600. Regarding passive shutdown capabilities, Japan team has performed a preliminary numerical analysis for ASTRID 600 using a complementary safety device, called a self-actuated shutdown system (SASS), one of the safety approaches of Japan. The mitigation measures of ASTRID 600 against a severe accident, such as a core catcher, molten corium discharge assembly, and the sodium void reactivity features of the CFV core, are promising to achieve in-vessel retention for both countries. The common design concept based on ASTRID 600 is feasible to demonstrate the SFR core and safety technologies for both countries.
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.
Kato, Atsushi; Kubo, Shigenobu; Chikazawa, Yoshitaka; Miyagawa, Takayuki*; Uchita, Masato*; Suzuno, Tetsuji*; Endo, Junji*; Kubo, Koji*; Murakami, Hisatomo*; Uzawa, Masayuki*; et al.
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22) (Internet), 11 Pages, 2022/04
The authors are carrying out conceptual design studies for a pool-type sodium-cooled fast reactor. There are main challenges such as measures against severe earthquake in Japan, thermal hydraulic in a reactor vessel (RV), a decay heat removal system design. When the JP-pool SFR of 650 MWe is installed in Japan, it shall be designed against the severe seismic conditions. Additionally, a newly three-dimensional seismic isolation system is under development.
Motoshima, Takayuki*; Matsui, Hiroya; Kawakubo, Masahiro*; Kobayashi, Masato*; Ichimura, Tetsuhiro*; Sugita, Yutaka
Nihon Genshiryoku Gakkai-Shi ATOMO
, 64(3), p.163 - 167, 2022/03
no abstracts in English
Wada, Yuki*; Enoto, Teruaki*; Kubo, Mamoru*; Nakazawa, Kazuhiro*; Shinoda, Taro*; Yonetoku, Daisuke*; Sawano, Tatsuya*; Yuasa, Takayuki*; Ushio, Tomoo*; Sato, Yosuke*; et al.
Geophysical Research Letters, 48(7), p.e2020GL091910_1 - e2020GL091910_11, 2021/04
Times Cited Count：29 Percentile：82.05(Geosciences, Multidisciplinary)Rodriguez, G.*; Varaine, F.*; Costes, L.*; Venard, C.*; Serre, F.*; Chanteclair, F.*; Chenaud, M.-S.*; Dechelette, F.*; Hourcade, E.*; Plancq, D.*; et al.
EPJ Nuclear Sciences & Technologies (Internet), 7, p.15_1 - 15_8, 2021/00
France (CEA and FRAMATOME) and Japan (JAEA, MHI and MFBR) have carried out studies to establish a common technical view regarding sodium-cooled fast reactor concept. Japan and France performed a common work to examine ways to develop a feasible common design concept, which could be built both in France and/or in Japan. This paper is providing a review of this joint synthesis on Sodium Fast Reactor design concept.
Kubo, Shigenobu; Chikazawa, Yoshitaka; Ohshima, Hiroyuki; Uchita, Masato*; Miyagawa, Takayuki*; Eto, Masao*; Suzuno, Tetsuji*; Matoba, Ichiyo*; Endo, Junji*; Watanabe, Osamu*; et al.
Mechanical Engineering Journal (Internet), 7(3), p.19-00489_1 - 19-00489_16, 2020/06
The authors are developing the design concept of pool-type sodium-cooled fast reactor (SFR) that addresses Japan's specific siting conditions such as earthquakes and meets safety design criteria (SDC) and safety design guidelines (SDGs) for Generation IV SFRs. The development of this concept will broaden not only options for reactor types in Japan but also the range and depth of international cooperation. A design concept of 1,500 MWt (650 MWe) class pool-type SFR was thought up by applying design technology obtained from the design of advanced loop-type SFR, named JSFR, equipped with safety measures that reflect results from the feasibility study on commercialized fast reactor cycle systems and fast reactor cycle technology development, improved maintainability and repairability, and lessons learned from the Fukushima Daiichi Nuclear Power Plants accident.
Kubo, Shigenobu; Chikazawa, Yoshitaka; Ohshima, Hiroyuki; Uchita, Masato*; Miyagawa, Takayuki*; Eto, Masao*; Suzuno, Tetsuji*; Matoba, Ichiyo*; Endo, Junji*; Watanabe, Osamu*; et al.
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 8 Pages, 2019/05
The authors are developing the design concept of pool-type sodium-cooled fast reactor (SFR) that addresses Japan's specific siting conditions such as earthquakes and meets safety design criteria (SDC) and safety design guidelines (SDGs) for Generation IV SFRs. The development of this concept will broaden not only options for reactor types in Japan but also the range and depth of international cooperation. A design concept of 1,500 MWt (650 MWe) class pool-type SFR was thought up by applying design technology obtained from the design of advanced loop-type SFR, named JSFR, equipped with safety measures that reflect results from the feasibility study on commercialized fast reactor cycle systems and fast reactor cycle technology development, improved maintainability and repairability, and lessons learned from the Fukushima Daiichi Nuclear Power Plants accident.
Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.
EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01
Times Cited Count：18 Percentile：98.41(Quantum Science & Technology)Wada, Yuki*; Bowers, G. S.*; Enoto, Teruaki*; Kamogawa, Masashi*; Nakamura, Yoshitaka*; Morimoto, Takeshi*; Smith, D.*; Furuta, Yoshihiro*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; et al.
Geophysical Research Letters, 45(11), p.5700 - 5707, 2018/06
Times Cited Count：37 Percentile：77.90(Geosciences, Multidisciplinary)Uchita, Masato*; Miyagawa, Takayuki*; Dozaki, Koji*; Chikazawa, Yoshitaka; Kubo, Shigenobu; Hayafune, Hiroki; Suzuno, Tetsuji*; Fukasawa, Tsuyoshi*; Kamishima, Yoshio*; Fujita, Satoshi*
Proceedings of 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) (CD-ROM), p.380 - 386, 2018/04
It is well-known that pool-type SFRs are the main streams recently in a field of Generation IV reactors. The pool-type encloses primary pumps and IHXs located around the core barrel in a main vessel. Consequently, the main vessel diameter trends to be larger than that of loop-types. From the viewpoint of commercialization in the future, a target of the vessel diameter and its weight including Sodium coolant will increase further. In this paper, the prospects are described in terms of seismic design and structural integrity for the thermal loadings to prevent buckling of the reactor vessel based on parameter studies with diameters of the vessel. In addition, the seismic isolation device which will be effective as a countermeasure is proposed in order to secure a margin against buckling of a large reactor vessel.
Usui, Aya; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Kitano, Toshihiko*; Takayama, Terumitsu*; Orimo, Takao*; Kanai, Shinji*; Aoki, Yuki*; Hashizume, Masashi*; et al.
Dai-28-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.117 - 119, 2015/12
no abstracts in English
Sawamura, Masaru; Hajima, Ryoichi; Kubo, Takayuki*; Saeki, Takayuki*; Iwashita, Yoshihisa*; Tongu, Hiromu*; Hokonohara, Hisao*; Cenni, E.*
Proceedings of 17th International Conference on RF Superconductivity (SRF 2015) (Internet), p.1196 - 1199, 2015/12
The spoke cavity is expected to have advantages for compact ERL accelerator for X-ray source based on laser Compton scattering. We have been developing the spoke cavity under a research program of MEXT, Japan to establish the fabrication process. Since our designed shape of the spoke cavity is complicated due to increase the RF properties, we have been designing the mold including the process of press work and the support parts for vacuum tolerance with the mechanical simulation. In this paper we present status of the spoke cavity fabrication.
Yuyama, Takahiro; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Ishizaka, Tomohisa; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Usui, Aya; Miyawaki, Nobumasa; et al.
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.302 - 304, 2015/09
no abstracts in English
Sawamura, Masaru; Hajima, Ryoichi; Nishimori, Nobuyuki; Nagai, Ryoji; Iwashita, Yoshihisa*; Tongu, Hiromu*; Kubo, Takayuki*; Saeki, Takayuki*
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.583 - 586, 2015/09
no abstracts in English
Hajima, Ryoichi; Sawamura, Masaru; Kubo, Takayuki*; Saeki, Takayuki*; Cenni, E.*; Iwashita, Yoshihisa*; Tongu, Hiromu*
Proceedings of 6th International Particle Accelerator Conference (IPAC '15) (Internet), p.2902 - 2904, 2015/06
A 5-year research program on the development of superconducting spoke cavities for electron accelerators has been funded by MEXT, Japan since 2013. The purpose of our program is establishing design and fabrication processes of superconducting spoke cavity optimized for compact X-ray sources based on laser Compton scattering. The spoke cavity is expected to realize a compact industrial-use X-ray source with a reasonable cost and easy operation. We have chosen a cavity frequency at 325 MHz due to possible operation at 4 K and carried out cavity shape optimization in terms of electromagnetic and mechanical properties. Production of press-forming dies is also in progress. In this paper, we present overview and up-to-date status of the research program.
