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Ueno, Yasuhiro*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.
Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11
Times Cited Count：3 Percentile：86.59(Physics, Atomic, Molecular & Chemical)
Sato, Wataru*; Komatsuda, Sayaka*; Osa, Akihiko; Sato, Tetsuya; Okubo, Yoshitaka*
Hyperfine Interactions, 237(1), p.113_1 - 113_6, 2016/12
Times Cited Count：2 Percentile：61.78(Physics, Atomic, Molecular & Chemical)The magnetic hyperfine field and electric field gradient at the
Cd(
Cd) and 
Cd(In) probe nuclei introduced in a perovskite manganese oxide 
(
250 K) were measured for the study of the local magnetism and structure by means of time-differential perturbed angular correlation spectroscopy. In the ferromagnetic phase at 77 K, a very slight supertransferred magnetic hyperfine field (SMHF) (
0.014 T) combined with a well-defined electric field gradient was observed at the nonmagnetic Cd nucleus on the La/Ca A site. This observation suggests that the large magnetic hyperfine field (
= 6.9 T) measured, in our previous work, at the 
Ce probe nucleus on the A site originates from the contribution of a 4
spin oriented by the SMHF from adjacent Mn ions.
Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.
Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12
Times Cited Count：7 Percentile：90.97(Physics, Atomic, Molecular & Chemical)Aoto, Kazumi; Chikazawa, Yoshitaka; Okubo, Tsutomu; Okada, Keizo*; Ito, Takaya*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Safe Technologies and Sustainable Scenarios (FR-13) (USB Flash Drive), 10 Pages, 2013/03
Overview of Japan Sodium-cooled Fast Reactor (JSFR) development status and reflection of lessons learned from the TEPCO's Fukushima Dai-ichi Nuclear Power Plant (1F) accident have been summarized. JSFR was recognized as a promising next generation nuclear reactor. Even though the JSFR safety design already took into account measures against severe accident situations and passive safety features such as passive shutdown system and natural convection decay heat removal systems in the 2010 design version, it is become aware of importance of design measures against severe accidents and extreme external events by the 1F accident. As recent activities, external hazard evaluations and design improvements reflecting lessons learned from 1F accident have been conducted. This paper also discusses importance of development of global safety design criteria and international Research and Development cooperation on safety design measures.
Hayafune, Hiroki; Kato, Atsushi; Chikazawa, Yoshitaka; Okubo, Tsutomu; Sagawa, Hiroshi*; Shimakawa, Yoshio*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Safe Technologies and Sustainable Scenarios (FR-13) (USB Flash Drive), 11 Pages, 2013/03
Evaluation of earthquake and tsunami on JSFR has been analyzed. For seismic design, safety components are confirmed to maintain their functions even against recent strong earthquakes. As for Tsunami, some parts of reactor building might be submerged including component cooling water system whose final heat sink is sea water. However, in the JSFR design, safety grade components are independent from component cooling water system (CCWS). The JSFR emergency power supply adopts a gas turbine system with air cooling, since JSFR does not basically require quick start-up of the emergency power supply thanks to the natural convection DHRS. Even in case of long station blackout, the DHRS could be activated by emergency batteries or manually and be operated continuously by natural convection.
Chikazawa, Yoshitaka; Okano, Yasushi; Hori, Toru*; Okubo, Yoshiyuki*; Shimakawa, Yoshio*; Tanaka, Toshihiko*
Journal of Nuclear Science and Technology, 43(8), p.829 - 843, 2006/08
Times Cited Count：4 Percentile：30.68(Nuclear Science & Technology)In phase II of the feasibility study of commercialized fast reactor cycle systems, we make a concept of a small sodium cooled reactor for a power source of a city with various requirements, such as, safety and economical competitiveness. Various reactor concepts are surveyed and a tank type reactor whose intermediate heat exchanger and primary main pumps are arranged in series is selected. In this study, a compact long life core and a simple reactor structure designs are pursued. The core type is three regional Zr concentration with one Pu enrichment core, the reactor outlet temperature achieves 550
C and the reactor electric output increases from 150MWe to 165MWe. The construction cost is much higher than the economical goal in the case of FOAK. But the construction cost in the case of NOAK is estimated to be 85.6% achieving the economical goal.
Aizawa, Kosuke; Chikazawa, Yoshitaka; Shiraishi, Tadashi*; Sakata, Hideyuki*; Okubo, Yoshiyuki*
no journal, ,
no abstracts in English
