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Pyeon, C. H.*; Vu, T. M.*; Yamanaka, Masao*; Sugawara, Takanori; Iwamoto, Hiroki; Nishihara, Kenji; Kim, S. H.*; Takahashi, Yoshiyuki*; Nakajima, Ken*; Tsujimoto, Kazufumi
Journal of Nuclear Science and Technology, 55(2), p.190 - 198, 2018/02
Times Cited Count：16 Percentile：85.18(Nuclear Science & Technology)At the Kyoto University Critical Assembly, a series of reaction rate experiments is conducted on the accelerator-driven system (ADS) with spallation neutrons generated by the combined use of 100 MeV protons and a lead and bismuth target in the subcritical state. The reaction rates are measured by the foil activation method to obtain neutron spectrum information on ADS. Numerical calculations are performed with MCNP6.1 and JENDL/HE-2007 for high-energy protons and spallation process, JENDL-4.0 for transport and JENDL/D-99 for reaction rates. The reaction rates depend on subcriticality is revealed by the accuracy of the C/E (calculation/experiment) values. Nonetheless, the accuracy of the reaction rates at high-energy thresholds remains an important issue in the fixed-source calculations.
Matsuda, Norihiro; Izumi, Yuichi*; Yamanaka, Yoshiyuki*; Gando, Toshiyuki*; Yamada, Masaaki*; Oishi, Koji*
EPJ Web of Conferences, 153, p.07001_1 - 07001_6, 2017/09
Times Cited Count：0 Percentile：0.03(Nuclear Science & Technology)
image crystalSerizawa, Hiroyuki; Oishi, Yuji*; Kaji, Yoshiyuki; Yamanaka, Shinsuke*
New Research Trends of Fluorite-Based Oxide Materials, p.243 - 262, 2015/01
The image crystal is a shape controllable negative crystal which is sometimes reported by mineralogist. The negative crystals formed in a large single-crystal mass have attracted interest as expensive jewelry because of their mysterious appearance and rarity. Nonetheless, for many scientist, the cavity has been nothing else than a volume defect which occurs in a single crystal by chance. However, the authors found unexpectedly that the image crystal is formed in UO when helium is enclosed in the gas bubble. They also found that the shape of the image crystal changes dramatically with the conditions of helium precipitation, which implies that the shape of the cavity should change depending on the inner pressure. A truncated octahedron-type, an octa-triacontahedron-type and a pentacontahedron-type negative crystal were observed. Recent study clarified that the growth process of the image crystal can be explained by a step free energy model rather than an attachment energy.
Serizawa, Hiroyuki; Matsunaga, Junji*; Haga, Yoshinori; Nakajima, Kunihisa; Akabori, Mitsuo; Tsuru, Tomohito; Kaji, Yoshiyuki; Kashibe, Shinji*; Oishi, Yuji*; Yamanaka, Shinsuke*
Crystal Growth & Design, 13(7), p.2815 - 2823, 2013/07
Times Cited Count：5 Percentile：42.72(Chemistry, Multidisciplinary)Since the shape of the negative crystal closely relates to the morphology of the crystal habits, the formation and the growth mechanism is important subject in a field of the physical science. Whereas, the negative crystal formed in a large single crystal mass has been arousing interest as an expensive jewelry because of its mysterious appearance and rarity. However, it is difficult to control the shape of this polyhedral cavity embedded in a solid medium arbitrary. Here we report the recent discovery on the growth process of the negative crystal. We found that precipitated helium forms the negative crystal in UO; the shape changes drastically with the condition of the helium precipitation. The transformation mechanism was discussed in this article. Our investigation implies that the shape of the negative crystal can be arbitrary controlled by controlling the precipitation condition.
Sakaguchi, Shinobu; Tachibana, Ikuya; Koshino, Katsuhiko; Shirozu, Hidetomo; Shirai, Nobutoshi; Imamoto, Nobuo; Tomita, Tsuneo; Tobita, Hiroo; Yamanaka, Atsushi; Kobayashi, Daisuke; et al.
JAEA-Technology 2011-006, 24 Pages, 2011/03
JAEA-Technology-2011-006.pdf:3.07MB
In the Niigataken Chuetsu-oki Earthquake on 2007, observed earthquake motion exceeded design base at the Kashiwazaki Kariwa nuclear plant. However, there was no earthquake damage in safety important equipments to stop reactor, to cool reactor, and to contain radioactive materials. One of this reason is said that many safety margin are included in the design and the permissible value. To know more accurate safety margin, shearing force examinations for the base bolts were conducted. In examinations, delegate test-bolts were made; the test bolts were selected from heavier equipment in Tokai Reprocessing Plant. In this report, the shearing strength obtained from the examinations shows more accurate safety margin.
Yamanaka, Shinsuke*; Uno, Masayoshi*; Kurosaki, Ken*; Osaka, Masahiko; Sato, Isamu; Namekawa, Takashi; Kato, Masato; Kihara, Yoshiyuki
JNC TY9400 2004-001, 111 Pages, 2004/04
JNC-TY9400-2004-001.pdf:2.81MB
As the fundamental study for MOX containing MA fuel, property measurement and its evaluation has been performed by JNC and Osaka university, respectively. Each results were compared, and the properties of MOX containing MA has been evaluated totally.
Shirato, Yoji; Yamanaka, Atsushi; Tsutagi, Koichi; Yoshino, Yasuyuki; Kishi, Yoshiyuki; Isobe, Hiroyasu
no journal, ,
no abstracts in English
Serizawa, Hiroyuki; Oishi, Yuji*; Haga, Yoshinori; Yamanaka, Shinsuke*; Tsuru, Tomohito; Kaji, Yoshiyuki; Matsunaga, Junji*; Kashibe, Shinji*
no journal, ,
We found that porous UO grain was formed by the precipitation of helium injected by HIP. SEM analysis showed that polyhedral negative crystals were formed in the sample. The shape of the negative crystal changes dramatically with the conditions of helium precipitation. A truncated octahedron-type, an octa-triacontahedron and a pentacontahedron-type negative crystal were observed. The change in the precipitation condition means the variation in the activity of helium in matrix. So, our study implies that the shape of the negative crystal should changes depending on the helium inner pressure enclosed in the negative crystal.
Serizawa, Hiroyuki; Oishi, Yuji*; Haga, Yoshinori; Yamanaka, Shinsuke*; Tsuru, Tomohito; Kaji, Yoshiyuki; Matsunaga, Junji*; Kashibe, Shinji*
no journal, ,
We found that porous UO grain was formed by the precipitation of helium injected by HIP. SEM analysis showed that polyhedral negative crystals were formed in the sample. The shape of the negative crystal changes dramatically with the conditions of helium precipitation. The change in the precipitation condition means the variation in the activity of helium in matrix. So, our study implies that the shape of the negative crystal should changes depending on the helium inner pressure enclosed in the negative crystal. It is difficult to arbitrarily control the shapes of these polyhedral negative crystals embedded in a solid medium. However, the shape of the negative crystal can easily be controlled by helium injection method. In this article, we call shape controlled negative crystal as image crystal. Here, we report a relationship between the surface energy and the shape and discuss the transformation mechanism of image crystal.
Serizawa, Hiroyuki; Kaji, Yoshiyuki; Oishi, Yuji*; Yamanaka, Shinsuke*; Matsunaga, Junji*
no journal, ,
We found that porous UO grain was formed by the precipitation of helium injected by HIP. Scanning electron microscopy analysis showed that polyhedral negative crystals were formed in the sample. The shape of the negative crystal changes dramatically with the conditions of helium precipitation. A truncated octahedron-type, an octa-triacontahedron-type, and a pentacontahedron-type negative crystal were observed. Our study implies that the shape of the negative crystal should change depending on the helium inner pressure enclosed in the negative crystal.
Anada, Keito*; Oishi, Yuji*; Serizawa, Hiroyuki; Kaji, Yoshiyuki; Muta, Hiroaki*; Kurosaki, Ken*; Yamanaka, Shinsuke*
no journal, ,
Polyhedral cavities which is called image crystal were observed in the Cerium Oxide sample sintered under reducing atmosphere. The facet became clear with decreasing O/M ratio which facilitates the atomic diffusion rate. This result suggests that the atomic diffusion rate of matrix significantly affects the formation of the image crystals.
Kishi, Yoshiyuki; Yasuda, Takeshi; Tokoro, Hayate; Yamanaka, Atsushi; Tsutagi, Koichi; Shirato, Yoji; Tanaka, Hitoshi
no journal, ,
High active liquid waste is stored in the facility equipped with cooling system and hydrogen scavenging system because of hydrogen generation due to radiolysis, and heat generation due to decay heat. The facilities related to these systems maintenance have been designed to be fed by emergency power generators in the conventional design. In addition to that, in light of the lessons learned from accident at the Fukushima Daiichi Nuclear Power Plant, we took safety measures for emergencies such as securement of the power supply system from power source vehicle to enable a quick recovery in the case of station black out in the Tokai Reprocessing Plant.
Yamanaka, Taiki*; Arai, Tsuyoshi*; Sato, Fuminori; Ito, Yoshiyuki; Horiguchi, Kenichi
no journal, ,
no abstracts in English
Serizawa, Hiroyuki; Kaji, Yoshiyuki; Yamamoto, Shunya*; Yasunaga, Kazushi*; Oishi, Yuji*; Yamanaka, Shinsuke*
no journal, ,
Pieces of CeO(100) thin film were heat treated at 1273 K for 2h. The films were irradiated with 130-keV He
ions from 400-keV ion implanter of TIARA. The ion doped film was heat treated at 1773 K for 2h in air. The sample for STEM analysis was prepared by FIB. It was found that many blisters are formed on the surface of the thin film. The idea of gas-driven blister growth on a metal surface was first proposed by Evans et al.. So, the blisters are considered to be formed by gas babble formed accompanied by precipitation of He just under the surface. Many gas babbles are formed in the thin film. The size of the gas bubble falls within the range 30-100 nm. The shape of the gas bubble is truncated octahedron but clearly different from that of void, which mean, the existence of He in the gas bubble effect on the shape of the gas bubble.
uptake rate in forests in Western HonshuTeramoto, Munemasa*; Liang, N.*; Sun, L.*; Kondo, Toshiaki*; Koarashi, Jun; Atarashi-Andoh, Mariko; Takagi, Masahiro*; Yamanaka, Norikazu*; Hirano, Takashi*; Takagi, Kentaro*; et al.
no journal, ,
