Hosomi, Kenji; Ma, Y.*; Ajimura, Shuhei*; Aoki, Kanae*; Dairaku, Seishi*; Fu, Y.*; Fujioka, Hiroyuki*; Futatsukawa, Kenta*; Imoto, Wataru*; Kakiguchi, Yutaka*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2015(8), p.081D01_1 - 081D01_8, 2015/08
Level structure of the C hypernucleus was precisely determined by means of -ray spectroscopy. We identified four -ray transitions via the C reaction using a germanium detector array, Hyperball2. The spacing of the ground-state doublet was measured to be (stat) (syst)keV from the direct transition. Excitation energies of the and states were measured to be , keV and , keV, respectively. The obtained level energies provide definitive references for the reaction spectroscopy of hypernuclei.
Sano, Asami; Hattori, Takanori; Arima, Hiroshi*; Yamada, Akihiro*; Tabata, Satoshi*; Kondo, Masahiro*; Nakamura, Akihiro*; Kagi, Hiroyuki*; Yagi, Takehiko*
Review of Scientific Instruments, 85(11), p.113905_1 - 113905_8, 2014/11
We developed a six-axis multi-anvil press, ATSUHIME, for high-pressure and high-temperature in situ time-of-flight neutron powder diffraction experiments. The press has six orthogonally oriented hydraulic rams that operate individually to compress a cubic sample assembly. Experiments indicate that the press can generate pressures up to 9.3 GPa and temperatures up to 2000 K using a 6-6-type cell assembly, with available sample volume of about 50 mm . Using a 6-8-type cell assembly, the available conditions expand to 16 GPa and 1273 K. Combination of the six-axis press and the collimation devices realized high-quality diffraction pattern with no contamination from the heater or the sample container surrounding the sample. This press constitutes a new tool for using neutron diffraction to study the structures of crystals and liquids under high pressures and temperatures.
Shimojo, Kojiro; Aoyagi, Noboru; Saito, Takumi*; Okamura, Hiroyuki; Kubota, Fukiko*; Goto, Masahiro*; Naganawa, Hirochika
Analytical Sciences, 30(2), p.263 - 269, 2014/02
Osawa, Kazuhito*; Goto, Junya*; Yamakami, Masahiro*; Yamaguchi, Masatake; Yagi, Masatoshi*
Physical Review B, 82(18), p.184117_1 - 184117_6, 2010/11
The configuration of multiple hydrogen atoms trapped in a tungsten monovacancy is investigated using first-principles calculations. Unlike previous computational studies, which have reported that hydrogen in BCC metal monovacancies occupies octahedral interstitial sites, it is found that the stable sites shift towards tetrahedral interstitial sites as the number of hydrogen atoms increases. As a result, a maximum of twelve hydrogen atoms can become trapped in a tungsten monovacancy.
Yagi, Daichi*; Yamada, Taro*; Kurihara, Kazuo; Onishi, Yuki*; Yamashita, Masahiro*; Tamada, Taro; Tanaka, Ichiro*; Kuroki, Ryota; Niimura, Nobuo*
Acta Crystallographica Section D, 65(9), p.892 - 899, 2009/09
A neutron crystallographic analysis of phosphate-free bovine pancreatic RNase A has been carried out at 1.7 resolution using the BIX-4 single-crystal diffractometer at the JRR-3 reactor of the Japan Atomic Energy Agency. The high resolution structural model allowed us to determine that His12 acts mainly as a general base in the catalytic process of RNase A. Numerous other distinctive structural features such as the hydrogen positions of methyl groups, hydroxyl groups, prolines, asparagines and glutamines were also determined at 1.7 resolution. The protonation and deprotonation states of all of the charged amino-acid residues allowed us to provide a definitive description of the hydrogen-bonding network around the active site and the H atoms of the key His48 residue. Differences in hydrogen-bond strengths for the -helices and -sheets were inferred from determination of the hydrogen-bond lengths and the H/D-exchange ratios of the backbone amide H atoms. The correlation between the B factors and hydrogen-bond lengths of the hydration water molecules was also determined.
Sakata, Mami; Yagi, Masahiro; Horiguchi, Hironori; Hirane, Nobuhiko
Nippon Hozen Gakkai Dai-6-Kai Gakujutsu Koenkai Yoshishu, p.275 - 278, 2009/08
A crack was found on a weld area of one reflector element in JRR-4 on December 28, 2007. The following examinations were carried out, visual examination, dimensional examination, fractography examination and so on. It was concluded that the main cause of the crack is the neutron-induced swelling of graphite in the reflector element. We tested radiographycally the other reflector elements. As the result, we determined that many of them were not in a suitable state to be used because of swelling of graphite. Based on the relation between the irradiation dose and swelling rate, the design of the new reflector elements has been carried out. We decided to test radiographycally all the new reflector elements as the future maintenance.
Yagi, Masahiro; Watanabe, Masanori; Oyama, Koji; Yamamoto, Kazuyoshi; Komeda, Masao; Kashima, Yoichi; Yamashita, Kiyonobu
Applied Radiation and Isotopes, 67(7-8), p.1225 - 1229, 2009/07
Komeda, Masao; Yamamoto, Kazuyoshi; Yagi, Masahiro; Sagawa, Hisashi
JAEA-Technology 2008-064, 77 Pages, 2008/10
We investigated the irradiation method to irradiate 12 inch NTD silicon uniformly in JRR-3, where 6 inch NTD silicon is being irradiated at present, by using MVP of the Monte Carlo calculation code. In the case of irradiating 12 inch NTD silicon, the deviation of the doping distribution in the radial direction becomes 1.17 by the same irradiation method of 6 inch NTD silicon. Therefore the thermal neutron filter was introduced for uniform doping (the deviation is less than 1.10) in the radial direction and the effect was analyzed. As the result, it was indicated that the deviation of the doping distribution in the radial direction became less than 1.1 by using the neutron filter, which was made from aluminum alloy of 2 mm thickness including natural boron of 1%.
Yagi, Masahiro; Horiguchi, Hironori; Yokoo, Kenji; Oyama, Koji; Kusunoki, Tsuyoshi
JAEA-Technology 2008-072, 79 Pages, 2008/09
A crack had been found on the weld of one reflector element in JRR-4. A survey revealed that the cause for the crack was the expansion of graphite reflector in the reflector element. It appeared that the expansion of graphite reflector was caused by fast neutron irradiation at low temperature. The survey confirmed radiographically that graphite reflectors in the other reflector elements without the crack expanded similarly by the irradiation growth. Irradiated graphite reflectors were carefully observed and were precisely measured the three dimensions after dismantling the irradiated reflector elements in order to understand quantitatively the irradiation growth behavior of IG-110 graphite under the JRR-4 operation condition. As the results, it was confirmed that growth of graphite reflectors increased with increasing of fast neutron fluence. The maximum irradiation growth per fast neutron fluence was 7.1310%m/n, the minimum was 4.2110%m/n, the average was 5.7110%m/n in the range of fast neutron fluence below 2.510n/m.
Yagi, Masahiro; Watanabe, Masanori; Oyama, Koji; Komeda, Masao; Yamamoto, Kazuyoshi; Kashima, Yoichi
JAEA-Technology 2008-015, 91 Pages, 2008/03
The irradiation experimental device is designed by surveying analytically an irradiation condition to improve the neutron flux distribution of the radial direction on NTD-Si by using neutron transportation calculation Monte Carlo calculation code MCNP5 in order to develop neutron irradiation technology for the large-diameter silicon to 12 inches diameter at the maximum and an irradiation experiment will be performed in JRR-4. Thus the validity of the design technique of the irradiation device will be confirmed by this experiment. The irradiation experimental device is installed in the side of the core tank outer wall. A 12 inches silicon ingot of 60cm in height is irradiated in a reflector cover which surrounds the silicon ingot for increasing the flux. The silicon ingot is rotated during irradiation in order to require the condition of uniformly distributed thermal neutron flux over whole circumferences. A uniform irradiation condition was achieved by the pass-through core method, in which silicon ingot moved up and down with rotating. The condition was satisfied when silicon was covered with the thermal neutron filter, which is made from aluminum alloy of thickness of 2mm with natural boron element ratio of 1.5%, and was moved in the range from -42mm to 22mm for the center of the reactor core. The deviation of the Si-30 neutron absorption reaction rate was range from -3.2% to +5.3% in the intermediate volume of 40cm height and the neutron absorption reaction ratio of the circumference to the center was within 1.09 in the volume.
Yokoo, Kenji; Horiguchi, Hironori; Yagi, Masahiro; Nagadomi, Hideki; Yamamoto, Kazuyoshi; Sasajima, Fumio; Oyama, Koji; Ishikuro, Yasuhiro; Sasaki, Tsutomu; Hirane, Nobuhiko; et al.
JAEA-Technology 2007-018, 104 Pages, 2007/03
Reactor operation training using JRR-4 (Japan Research Reactor No.4) was started in FY 1969, one of the curriculums of Nuclear Technology and Education Center (NuTEC). After that, the program was updated and carried out for reactor operation training, control rod calibration, and measurement of various kind of characteristics. JRR-4 has been contributed for nuclear engineer training that is over 1,700 trainees from bother domestic and foreign countries. JRR-4 can be used for experiment from zero power to 3500kW, and the trainees can make experience to operate the reactor from start up to shut down, not only zero-power experiments (critical approach, control rod calibration, reactivity measurement, etc.) but also other experiments under high power operation (xenon effect, temperature effects, reactor power calibration, etc.). This report is based on various kinds of guidance texts using for training, and collected for operation and experiments for reactor physics.
Hirane, Nobuhiko; Ishikuro, Yasuhiro; Nagadomi, Hideki; Yokoo, Kenji; Horiguchi, Hironori; Nemoto, Takumi; Yamamoto, Kazuyoshi; Yagi, Masahiro; Arai, Nobuyoshi; Watanabe, Shukichi; et al.
JAEA-Technology 2006-028, 115 Pages, 2006/03
JRR-4, a light-water-moderated and cooled, swimming pool type research reactor using high-enriched uranium plate-type fuels had been operated from 1965 to 1996. In order to convert to low-enriched-uranium-silicied fuels, modification work had been carried out for 2 years, from 1996 to 1998. After the modification, start-up experiments were carried out to obtain characteristics of the low-enriched-uranium-silicied fuel core. The measured excess reactivity, reactor shutdown margin and the maximum reactivity addition rate satisfied the nuclear limitation of the safety report for licensing. It was confirmed that conversion to low-enriched-uranium-silicied fuels was carried out properly. Besides, the necessary data for reactor operation were obtained, such as nuclear, thermal hydraulic and reactor control characteristics. This report describes the results of start-up experiments and burnup experiments. The first criticality of low-enriched-uranium-silicied core was achieved on 14th July 1998, and the operation for joint-use has been carried out since 6th October 1998.
Ishida, Shinichi; Abe, Katsunori*; Ando, Akira*; Chujo, T.*; Fujii, Tsuneyuki; Fujita, Takaaki; Goto, Seiichi*; Hanada, Kazuaki*; Hatayama, Akiyoshi*; Hino, Tomoaki*; et al.
Nuclear Fusion, 43(7), p.606 - 613, 2003/07
no abstracts in English
Ishida, Shinichi; Abe, Katsunori*; Ando, Akira*; Cho, T.*; Fujii, Tsuneyuki; Fujita, Takaaki; Goto, Seiichi*; Hanada, Kazuaki*; Hatayama, Akiyoshi*; Hino, Tomoaki*; et al.
Nuclear Fusion, 43(7), p.606 - 613, 2003/07
no abstracts in English
Higuchi, Kenji; Imamura, Toshiyuki*; Suzuki, Yoshio; Shimizu, Futoshi; Machida, Masahiko; Otani, Takayuki; Hasegawa, Yukihiro*; Yamagishi, Nobuhiro*; Kimura, Kazuyuki*; Aoyagi, Tetsuo; et al.
Lecture Notes in Computer Science 2858, p.245 - 257, 2003/00
Prototype of the middleware for Grid project promoted by national institutes in Japan has been developed. Key technologies that are indispensable for construction of virtual organization were already implemented onto the prototype of middleware and examined in practical computer/network system from a view point of availability. In addition several kinds of scientific applications are being executed on the prototype system. It seems that successful result in the implementation of those technologies such as security infrastructure, component programming and collaborative visualization in practical computer/network systems means significant progress in Science Grid in Japan.
Higuchi, Kenji; Otani, Takayuki; Hasegawa, Yukihiro*; Suzuki, Yoshio; Yamagishi, Nobuhiro*; Kimura, Kazuyuki*; Aoyagi, Tetsuo; Nakajima, Norihiro; Fukuda, Masahiro; Imamura, Toshiyuki*; et al.
Proceedings of International Conference on Supercomputing in Nuclear Applications (SNA 2003) (CD-ROM), 11 Pages, 2003/00
An experimental application of Grid computing was executed in ITBL project promoted by six member institutes of MEXT. Key technologies that are indispensable for construction of virtual organization were implemented onto ITBL Middleware and examined in the experiment from a view point of availability. It seems that successful result in the implementation and examination of those technologies such as security infrastructure, component programming and collaborative visualization in practical computer/network systems means significant progress in Science Grid in Japan.
Yagi, Daichi*; Ebata, Toshinobu*; Ichige, Toshikatsu*; Kobayashi, Yoichiro*; Ishikawa, Takuya*; Yamashita, Masahiro*; Onishi, Yuki*; Tanaka, Ichiro*; Kurihara, Kazuo; Niimura, Nobuo*
no journal, ,
no abstracts in English
Yagi, Masahiro; Kashima, Yoichi; Nagadomi, Hideki; Watanabe, Shukichi
no journal, ,
no abstracts in English
Yagi, Masahiro; Kashima, Yoichi; Watanabe, Masanori; Yamamoto, Kazuyoshi
no journal, ,
The irradiation experimental device is designed by surveying analytically an irradiation condition to improve the neutron flux distribution of the diameter direction on NTD-Si by using Monte Carlo calculation code MCNP5 in order to develop neutron irradiation technology for the large-diameter silicon to 12 inches diameter at the maximum. Some irradiation experiment will be performed to confirm validity of the design technique in JRR-4 by using the experimental device for the 12 inches NTD-Si ingot. The experimental device is installed in the No.1 reactor pool side of the core tank outer wall. The 12 inches silicon of 60cm in height is irradiated in a reflector cover which surrounds the silicon for increasing the flux. The silicon also is irradiated with rotating in order to require the condition of uniformly distributed thermal neutron flux over whole circumferences. A uniform irradiation condition was achieved by the pass-through core method with adding the thermal neutron filter which covers the silicon surface and is able to move up and down with rotating. The condition was satisfied when silicon was covered with the thermal neutron filter, which is made from aluminum alloy of 2mm thickness with natural boron element ratio of 1.5%, and was run in the range from -42mm to 22mm for the center of the reactor core. The deviation of the Si-30 neutron absorption reaction rate was range from -3.22% to +5.27% in the intermediate volume of 40cm height and the neutron absorption reaction ratio of the circumference to the center was within 1.09 in the volume.
Kashima, Yoichi; Yagi, Masahiro; Watanabe, Masanori; Yamamoto, Kazuyoshi
no journal, ,
In JRR-4, a irradiation experimental device for 12 inches NTD-Si (Neutron Transmutation Doping Silicon) ingot will be installed to confirm the validity of the uniform irradiation condition which has been derived analytically in order to develop neutron irradiation technology for the large-diameter NTD-Si semiconductor to 12 inches diameter at the maximum. In installation, various limitations occurred, but some design policy was set in consideration of these limitations and the mechanical design of the irradiation experimental device was performed. As the result of mechanical design, it is possible to produce the irradiation experimental device which satisfied the irradiation condition derived by analysis without interfering it with an existing device in the future.