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Kamiya, Junichiro; Nii, Keisuke*; Kabumoto, Hiroshi; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; Matsuda, Makoto; Moriya, Katsuhiro; Ida, Yoshiaki*; et al.
e-Journal of Surface Science and Nanotechnology (Internet), 21(4), p.344 - 349, 2023/05
no abstracts in English
Saha, P. K.; Okabe, Kota; Nakanoya, Takamitsu; Yoshimoto, Masahiro; Shobuda, Yoshihiro; Harada, Hiroyuki; Tamura, Fumihiko; Okita, Hidefumi; Hatakeyama, Shuichiro; Moriya, Katsuhiro; et al.
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1 - 5, 2023/01
Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count：5 Percentile：87.42(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
s for the Future Upgrade of 
Tandem Superconducting BoosterKondo, Yasuhiro; Harada, Hiroyuki; Kabumoto, Hiroshi; Kamiya, Junichiro; Matsuda, Makoto; Moriya, Katsuhiro; Tamura, Jun; Kako, Eiji*; Domae, Takeshi*; Sakai, Hiroshi*; et al.
Proceedings of 20th International Conference on RF Superconductivity (SRF 2021) (Internet), p.299 - 302, 2021/10
The Japan Atomic Energy Agency (JAEA) tandem booster is one of the pioneering superconducting heavy ion linac in the world. It consists of 40 QWRs with an operation frequency of 130 MHz and 
, and has potential to accelerate various ions up to Au to 10 MeV/u. The user operation was started in 1994, however, it has been suspended since the Great East Japan Earthquake in 2011. Recently, in addition to the efforts to restart the tandem booster, activities to develop new lower-beta cavities to improve the acceleration efficiency of heavier ions such as Uranium has been launched. In this work, the current status of the design study of the QWRS for the JAEA tandem facility is presented. Electro-magnetic design using simulation code was performed and acceleration gradient of 5.7 MV/m and 6.6 MV/m was obtained for 130-MHz and 65-MHz QWRs, respectively.
Moriya, Katsuhiro; Harada, Hiroyuki; Liu, Y.*; Otani, Masashi*
Journal of Physics; Conference Series, 1350, p.012140_1 - 012140_5, 2019/11
Times Cited Count：0 Percentile：0.06(Physics, Particles & Fields)Chimura, Motoki*; Harada, Hiroyuki; Moriya, Katsuhiro; Okabe, Kota; Kinsho, Michikazu
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.728 - 732, 2019/07
The increase of space charge effect in high intensity beam causes the increase of the beam-loss. Beam loss limits beam intensity for accelerator equipment activation. Therefore, it is important to suppress the emittance growth due to the space charge effect. I focused on the low energy region in the linac where the space charge effect becomes remarkable. In order to identify the origin of the emittance growth due to the effect, a simulation was performed with a 3-D particle-in-cell simulation code, and evaluated the influence of the effects in the J-PARC medium energy beam transport line (MEBT1) entrance to DTL exit. As a result, it was confirmed that distortion of phase space distribution occurred due to nonlinear space charge force and that leading to emittance growth. I proposed to suppress the emittance growth by using an octupole magnet that gives nonlinear force to the beam. We report the new method and simulation results.
Niwa, Hideharu*; Saito, Makoto*; Kobayashi, Masaki*; Harada, Yoshihisa*; Oshima, Masaharu*; Moriya, Shogo*; Matsubayashi, Katsuyuki*; Nabae, Yuta*; Kuroki, Shigeki*; Ikeda, Takashi; et al.
Journal of Power Sources, 223, p.30 - 35, 2013/02
Times Cited Count：18 Percentile：50.75(Chemistry, Physical)To design non-platinum, inexpensive, but high performance carbon-based cathode catalysts for polymer electrolyte fuel cells, it is important to elucidate the active site for oxygen reduction reaction (ORR). However, it is difficult to directly identify the active site by applying conventional structural or electronic probes to such complex systems. Here, we used C 1
X-ray absorption spectroscopy (XAS) to observe electronic structure of carbon in iron phthalocyanine-based catalysts, and found a signature of edge exposure below the 
edge, whose intensity is well correlated with the ORR activity. These results demonstrate that C 1 XAS can be used to characterize the ORR activity of carbon-based cathode catalysts in terms of the edge exposure.
Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu
Nuclear Engineering and Design, 241(1), p.366 - 377, 2011/01
Times Cited Count：37 Percentile：92.93(Nuclear Science & Technology)Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu
Journal of Nuclear Science and Technology, 47(4), p.384 - 395, 2010/04
Times Cited Count：40 Percentile：92.45(Nuclear Science & Technology)Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu
Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13) (CD-ROM), 15 Pages, 2009/09
Although the decay heat from fuel debris drives the coolant boiling in fast reactor accident conditions, the present experiments were conducted by employing depressurization boiling of water to simulate axially increasing void distribution in a debris bed instead of conventional heating or gas injection from the debris bottom. Good agreements on self-leveling occurrence were obtained between model predictions and experimental results. Extrapolation of the present model was also discussed against reactor conditions.
Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu
Proceedings of 6th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-6) (USB Flash Drive), 8 Pages, 2008/11
In the present study, characteristics of self-leveling behaviors were investigated experimentally with simulant materials. The present experiments employed depressurization boiling of water to simulate axially increasing void distribution in a debris bed, which consists of solid particles of alumina or lead with different density. The particle size (from 0.5 mm to 6 mm in diameter) and shape (spherical or non-spherical particles) were also taken as experimental parameters. A rough criteria for self-leveling occurrence is proposed and compared with the experimental results.
*; *; *; Abe, Yasuhiro*; *; *; *
PNC TN941 80-169, 71 Pages, 1980/10
To confirm the safety of fast experimental reactor "JOYO", the material-surveillance tests are required. As the data of material-surveillance tests are too restrictive to judge the safety, it is evidently necessary to analyze the numerous back up data for evaluating the results. This report is one of the back up tests. We studied the effects of thermal aging on tensile and creep properties of relative plate and its weldment for the reactor vessel of "JOYO". Themal aging were performed 100 
10,000h at 400 550
C with and without stress. This results obtained are summarized as follows. (1)Results of tensile properties (a)Yield strength of base metal and welded joing aged above 500C for long time increased, but tensile strength, uniform elongation, ruptured elongation and reduction of area decreased. (b)Above tendency is accelerated with stress aging. (2)Results of creep rupture properties (a)Slight reduction in short-term creep rupture strength of base matal aged is observed, but is not observed in long-term properties. (b)No effects of themal aging are observed in welded joints. (c)It seemed to think the creep rupture strength of base metal and welded joints aged long-term at high temperature satisfied both of the value of "JOYO" guide line and the design curve of ASME.
*; *; Koyama, Masahiro; *; *; *; *
PNC TN941 79-204, 47 Pages, 1979/11
To make sure that the core materials of the fast experimental reactor "Joyo" are in safety conditions, and to get basic knowledge about the behavior of FBR core materials after irradiation, we carried out post-irradiation examination on a wrapper tube (SUS316, 10% C.W.). The wrapper tube was fabricated into the subassembly PPJX15 and used during the power-up stage of "Joyo" MK-I core (Irradiation temperature 370C 460C, maximum neutron fluence 6.1
10
n/cm
, E 
0.1 Mev). Visual inspection, tensile tests metallurgical test, hardness test and density measurement were performed, and compared with the data of PPJDIA, examined before (Irradiation temperature 370C 450C, maximum neutron fluence 3.010 n/cm, E 0.1 MeV). The results obtained are summarized as follows. (1) No harmful change on the wrapper tube surface was observed by periscope. (2) As the results of tensile tests at 400C and 450C, ultimate tensile strength was 66 69 Kg/mm at 400C and about 65 Kg/mm at 450C. Yield strength (0.2% offset) was 46 52 Kg/mm at 400C and 46 49 Kg/mm at 450C. The results of PPJDIA and PPJX15 show that both ultimate and yield strength are increasing according to the neutron fluence. The elongation decreased about 5% by irradiation. (3) Density was 7.996 g/cm
and slightly larger than the value of unirradiated tubes (7.974g/cm are.), but the density of PPJDIA tube was not changed from unirradiated tubes, so it is not clear that this change is caused by irradiation. or not (4) Irradiation-hardening was observed by hardness test. (5) Irradiated wrapper tube had normal austenitic structure and no change as carburization or decarburization was observed.
Suzuki, Kazuhisa; Yamanouchi, Sadamu; Tani, Satoshi; Ichige, Akio; Naito, Takeshi; Harada, Mamoru; Ito, Masahiko; Osugi, Shoichi*; Shibata, Kenichi*
PNC TN951 76-05, 70 Pages, 1976/03
The serpentine concentrate in which two kinds of cement were used as a binder was irradiated in JMTR to the fast neutron fluence -1.7
n/cm (E1Mev) and thermal neutron fluence -1.510
n/cm. Ave-rage irradiation temperature was estimated to be 200
. Prior to the postirradiation examination, effect of thermal history was investigated in out-of-pile test. The integrity of specimens were kept after irradiation. From the results of thermal history examination and the post-irradiation examination, it was clearly noticed that the changes occuring in dimensions, weight and compressive strength were caused mainly by the thermal effect. The change in the Young's modulus seemed to be caused by the effect of both heating and neutron irradiation. It wasconcluded that the ordinary portland cement with the serpentine concrete is better than that of almina cement.
; ; ; ;
Hoken Butsuri, 8(2), p.67 - 71, 1973/02
no abstracts in English
Harada, Tetsushi*; Hirahara, Daisuke*; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Suzuki, Toru; Yamano, Hidemasa; Tobita, Yoshiharu
no journal, ,
no abstracts in English
Moriya, Katsuhiro; Harada, Hiroyuki; Miura, Akihiko; Futatsukawa, Kenta*
no journal, ,
no abstracts in English
Moriya, Katsuhiro; Harada, Hiroyuki
no journal, ,
no abstracts in English
