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Yashima, Hiroshi*; Sekimoto, Shun*; Ninomiya, Kazuhiko*; Kasamatsu, Yoshitaka*; Shima, Tatsushi*; Takahashi, Naruto*; Shinohara, Atsushi*; Matsumura, Hiroshi*; Satoh, Daiki; Iwamoto, Yosuke; et al.
Radiation Protection Dosimetry, 161(1-4), p.139 - 143, 2014/10
Times Cited Count：2 Percentile：15.74(Environmental Sciences)The neutron activation cross sections up to GeV are important for the neutron dosimetry of the radiation field in high-energy and high-intensity accelerator facilities for a project of intense spallation neutron source. But the evaluation of neutron activation cross section data is not enough above 20 MeV because experimental data are still scarce. This study aimed to measure the neutron activation cross sections of Bi and Co by using a quasi-monoenergetic neutron field. In this symposium, we will present obtained experimental cross section data with the other experimental data (neutron-induced and proton-induced), the calculated data by PHITS code and the evaluated nuclear data.
Matsuda, Norihiro; Kasugai, Yoshimi; Matsumura, Hiroshi*; Iwase, Hiroshi*; Toyoda, Akihiro*; Yashima, Hiroshi*; Sekimoto, Shun*; Oishi, Koji*; Sakamoto, Yukio*; Nakashima, Hiroshi; et al.
Progress in Nuclear Science and Technology (Internet), 4, p.337 - 340, 2014/04
The Neutrinos at the Main Injector (NuMI) at Fermilab produces intense neutrino beam to investigate the phenomena of the neutrino mixing and oscillation. The Hadron Absorber, consists of thick blocks of aluminum, iron and concrete, is placed at the end of decay volume as a dump for primary proton and secondary particles generated in NuMI. In order to estimate the shielding effect, the reaction rate measurements with activation detector were carried out on the back surface of the absorber. The induced activities in the detectors were measured by analyzing their 
-ray spectra using HPGe detectors. Two kind of peak was showed on two-dimensional distributions of obtained reaction rates at right angle to the beam direction. One was strong peaks at the both horizontal side. And, another smaller was at the top. It was concluded that these peaks were the results of particles streaming through the gaps in the Hadron Absorber shielding.
Sekimoto, Shun*; Utsunomiya, Takashi*; Yashima, Hiroshi*; Ninomiya, Kazuhiko*; Omoto, Takashi*; Nakagaki, Reiko*; Shima, Tatsushi*; Takahashi, Naruto*; Shinohara, Atsushi*; Kinoshita, Norikazu*; et al.
Progress in Nuclear Science and Technology (Internet), 1, p.89 - 93, 2011/02
In this work, we tried to determine reaction cross sections for Y and Tb induced by neutrons at 300 MeV, which have never been reported. The irradiations were carried out using neutrons produced through 
Li(p, n) reaction at N0 beam line in the Research Center for Nuclear Physics (RCNP), Osaka University. To estimate quasi-monoenergetic neutron induced cross sections, the target stacks of Y and Tb were irradiated on the two angles of 0 degree and 30 degree for the axis of the primary proton beam. Neutron cross sections were estimated by subtracting the activities produced in the samples placed on 30 degree from those of 0 degree to correct the contribution of the low energy tail in the neutron spectrum.
Iwanaga, Kohei*; Sekimoto, Hiroshi*; Mori, Takamasa
Journal of Nuclear Science and Technology, 45(11), p.1099 - 1107, 2008/11
Times Cited Count：2 Percentile：16.65(Nuclear Science & Technology)The Monte Carlo method is applied to solve the space-dependent kinetics equations of transient in source-driven subcritical systems whose change is much slower than the prompt neutron lifetime. In the present paper, the time derivative of neutron equation is set zero, though the time derivative of delayed neutron precursor equation is treated without any approximations. The neutron counts measured by small fission chambers at the subcritical kinetics experiment using JAEA FCA are compared with those calculated by the present method. The agreement is good, and the excellent performance of our method for space dependent neutron kinetics is shown.
Sekimoto, Hiroshi*
JAERI-Tech 2005-008, 111 Pages, 2005/03
JAERI-Tech-2005-008.pdf:15.9MB
The CANDLE burnup strategy is a new reactor burnup concept, where the distributions of fuel nuclide densities, neutron flux, and power density move with the same constant speed from bottom to top (or from top to bottom) of the core and without any change in their shapes. Therefore, any burnup control mechanisms are not required, and reactor characteristics do not change along burnup. The reactor is simple and safe. When this burnup scheme is applied to some neutron rich fast reactors, either natural or depleted uranium can be utilized as fresh fuel after second core and the bunrup of discharged fuel is about 40%. It means that the nuclear energy can be utilized for many hundreds years without new mining, enrichment and reprocessing, and the amount of spent fuel can be reduced considerably. Compared to fast reactors, application of CANDLE burnup to prismatic fuel high-temperature gas cooled reactors is very easy. In this report, the applications of CANDLE burnup to both these types of reactors are studied.
Iwanaga, Kohei; Yamane, Tsuyoshi; Nishihara, Kenji; Okajima, Shigeaki; Sekimoto, Hiroshi*; Asaoka, Takumi*
Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 10 Pages, 2003/04
no abstracts in English
Takahashi, Minoru*; Sekimoto, Hiroshi*
JNC TY9400 2003-003, 64 Pages, 2003/03
JNC-TY9400-2003-003.pdf:3.18MB
The evaluation of corrosion behaviors of core and structural materials in lead bismuth eutectic is one of the key issues for the utilization of lead bismuth eutectic as a coolant of the primary loops of lead bismuth cooled fast breeder reactors (FBRs) and the intermediate heat transport media of new-type steam generators of the sodium cooled FBRs. The purpose of the present study is to establish corrosion test techniques in lead bismuth eutectic flow. The techniques of steel corrosion test and oxygen control in flowing lead bismuth eutectic, and the technologies of a lead bismuth flow test at high temperature and high velocity were developed through corrosion test using a lead bismuth flow test loop of the Tokyo Institute of Technology in JFY2002. The major results are summarized as follows: (1)Techniques of fablication, mount and rinse of corrosion specimens, measurement method of weight loss, and SEM/EDX analysis method have been establishied through lead bismuth corrosion test. (2)Weight losses were measured, corrosion and lead bismuth-adhered layers and eroded parts were observed in two 1000 hr-corrosion tests, and the results were compared with each other for twelve existmg steels including ODS,F82H and SUH-3 (3)An oxygen sensor made of zirconia electrolyte structurally resistant to thermal stress and thermal shock was developed and tested in the lead bismuth flow loop. Good performance has been obtained. (4)An oxygen control method by injecting argon and hydrogen mixture gas containing steam into lead bismuth was applied to the lead bismuth flow loop, and technical issues for the development of the oxygen control method were extracted. (5)Technical measures for freezing and leakage of lead bismuth in the flow loop were accumulated. (6)Technical measures for flow rate decrease/blockage due to precipitation of oxide and corrosion products in a low temperature section of the lead bismuth flow loop were accumulated. (7)Electromagnetic flow meters with MI
Sekimoto, Hiroshi*; Igashira, Masayuki*; Yano, Toyohiko*; Obara, Toru*; Osaki, Toshiro*
JAERI-Tech 2002-008, 58 Pages, 2002/03
no abstracts in English
Obara, Toru*; Nakajima, Ken; Miyoshi, Yoshinori; Sekimoto, Hiroshi*
JAERI-Research 2001-037, 60 Pages, 2001/06
JAERI-Research-2001-037.pdf:2.7MB
no abstracts in English
Shelley, A.*; Akie, Hiroshi; Takano, Hideki; Sekimoto, Hiroshi*
Journal of Nuclear Science and Technology, 38(2), p.134 - 142, 2001/02
no abstracts in English
Shelley, A.*; Akie, Hiroshi; Takano, Hideki; Sekimoto, Hiroshi*
Progress in Nuclear Energy, 38(3-4), p.439 - 442, 2001/02
Times Cited Count：9 Percentile：55.57(Nuclear Science & Technology)no abstracts in English
Afroza, S.*; Akie, Hiroshi; Takano, Hideki; Sekimoto, Hiroshi*
Nuclear Technology, 131(2), p.197 - 209, 2000/08
Times Cited Count：4 Percentile：32.34(Nuclear Science & Technology)no abstracts in English
+ZrO, PuO+ThO and MOX fueled LWRsShelley, A.*; Akie, Hiroshi; Takano, Hideki; Sekimoto, Hiroshi*
JAERI-Research 99-051, p.51 - 0, 1999/09
JAERI-Research-99-051.pdf:2.05MB
no abstracts in English
Obara, Toru*; Nakajima, Ken; ; Sekimoto, Hiroshi*; Suzaki, Takenori
JAERI-M 94-004, 40 Pages, 1994/02
no abstracts in English
; Sasamoto, Nobuo; Mori, Seiji*; ; Kawai, Masayoshi*; ; Sakurai, Kiyoshi; Shin, Kazuo*; Sekimoto, Hiroshi*; Oyama, Yukio; et al.
JAERI-M 87-203, 230 Pages, 1987/12
no abstracts in English
Iwanaga, Kohei; Kurata, Yuji; Oigawa, Hiroyuki; Sekimoto, Hiroshi*
no journal, ,
In this study, we performed to reduction of the peaking factor in accelerator driven system (ADS). The peaking factor influences direct for the temperature of the fuel cladding. In this time, multi regionalization of the reactor core and the fuel dilution material ratio every cycle were adjusted by adjusting a fuel pin diameter and a fuel diluent ratio, the peaking was reduced, and, as a result, it succeeded in the decrease of the cladding surface temperature of 120
C compared with one region core.
Matsuda, Norihiro; Kasugai, Yoshimi; Sakamoto, Yukio; Nakashima, Hiroshi; Matsumura, Hiroshi*; Iwase, Hiroshi*; Toyoda, Akihiro*; Yashima, Hiroshi*; Sekimoto, Shun*; Oishi, Koji*; et al.
no journal, ,
no abstracts in English
