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研究報告21-1
論文
原 正憲、渡辺国昭
常田貴志*、川畑常真*、松田健二*、池野進*
富山大学水素同位体科学研究センター
*富山大学工学部
〒930-8555 富山市五福3190
Masanori HARA, Kuniaki WATANABE
Takashi TSUNEDA*, Tokimasa KAWABATA*, Kenji MATSUDA*, Susumu IKENO*
Hydrogen Isotope Research Center,
*Mater. Sci. and Eng., Faculty of Eng.,
Toyama University, Gofuku 3190, Toyama 930-8555, Japan
Abstract
Zr2Co disproportionated to ZrH2 and ZrCo on a wide range of temperatures and pressures. The X-ray diffraction patterns of disproportionated Zr2Co were constructed broad peaks that meant to consist of fine crystallite. To evaluate the temperature and pressure dependence of nucleation of products, the grain size of ZrH2 was calculated on a half width of ZrH2 111 peak by using Sherrer equation. It was found that the grain size did not depend on disproportionation conditions such as temperature and pressure. Zr2Ni also disproportionated and the grain size was not affected by temperature and pressure. These results indicate that the probability of nucleation does not depend on temperature and pressure. The disproportionation rates of Zr2M are determined mainly by the crystal growth rate of products. However, Zr2NiH5 was formed under the condition of low pressure. The appearance of disproportionation was affected by amount of absorbed hydrogen.
研究報告21-2
論文
波多野雄治、能村衛、渡辺国昭
富山大学水素同位体科学研究センター
〒930-8555 富山市五福3190
Alexander I. Livshits, Andrei O. Busnyuk
Bonch-Bruyevich University of Telecommunications
61 Moika, St Petersberg 191186, Russia
中村幸男、大藪修義
核融合科学研究所
〒509-5292 岐阜県土岐市下石町332-6
Yuji Hanano, Mamoru Nomura, Kuniaki Watanabe
Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930-8555, Japan
Alexander I. Livshits, Andrei O. Busnyuk
Bonch-Bruyevich University of Telecommunications
61 Moika, St Petersberg 191186, Russia
Yukio Nakamura, Nobuyoshi Ohyabu
National Institute for Fusion Science
Oroshi-cho, Toki 509-5292, Japan
Abstract
A new apparatus was constructed to examine gas-, atom- and Plasma-driven permeation of hydrogen isotopes through group VA metal membranes with precisely controlled surface states. Absorption and desorption experiments are also possible. The new apparatus consists of two vacuum chambers, an upstream chamber and a downstream chamber, separated by a specimen membrane. Both chambers are evacuated by turbo-molecular pumps and sputter-ion pumps. The upstream chamber is equipped with Ta filaments serving as atomizers in atom-driven permeation experiments and cathodes in plasma-driven permeation experiments. The specimen membrane is formed into a tubular and electrically isolated from the chamber. Hence, ohmic heating of the membrane is possible, and this feature of the membrane is suitable for surface cleaning by high-temperature heating and impurity doping for the control of surface chemical composition through surface segregation. Both chambers were evacuated to 1x10-7 Pa after baking. The main component of residual gas was H2, and the partial pressures of impurity gases other than H2 were ca. 1x10-8 Pa. Gas- and atom-driven permeation experiments were successfully carried out with hydrogen gas for Nb membrane activated by heating in vacuum at 1173K. Superpermeation was observed in the atom-driven permeation experiments. Absorption experiments with a clean surface were also carried out. The surface was, however, cleaned only partially, because the temperature distribution was not uniform during high-temperature heating. Nevertheless, surface cleanliness was retained during absorption experiments under the present vacuum conditions. A new membrane assembly that will enable a uniform temperature distribution is now under construction.
研究報告21-3
論文
松山政夫、吉田勝彦、渡辺国昭
富山大学水素同位体科学研究センター
〒930-8555 富山市五福3190
岩切宏友、吉田直亮
九州大学応用力学研究所
〒816-8580 福岡県春日市春日公園6-1
Masao Matsuyama, Katuhiko Yoshida, Kuniaki Watanabe
Hydrogen Isotope Research Center, Toyama Univ., Gofuku 3190, Toyama 930-8555, Japan
Hirotomo Iwakiri, Naoaki Yoshida
Research Institute for Applied Mechanics, Kyushu Univ., Kasuga, Fukuoka 816-8580, Japan
Abstract
Thermal behavior of tritium implanted in tungsten pre-irradiated with a given fluence of helium was examined by β-ray induced X-ray spectrometry (BIXS) under a condition of isochronal heating. To estimate changes in tritium distribution caused by heating, Ar(Kα) and W(Mα) X-rays were mainly utilized as probes of tritium detection. The intensity of the former X-rays linearly decreased with increase in heating temperature, while that of the latter X-rays was almost constant up to 600K and dramatically decreased above this temperature, indicating existence of strong trap sites. Such thermal behavior on X-ray intensity coincides with the understanding of thermal desorption spectra of deuterium. It was thought, therefore, that strong trap sites of tritium were due to the effects of bubbles generated by the helium pre-irradiation, and the trapping energy of tritium was estimated to be about 1.2 e.V. Moreover, change in depth profiles of tritium with heating was evaluated by analyzing the observed X-ray spectra by means of computer simulation, and changes in the concentration of tritium retained in surface layers were examined.
研究報告21-4
論文
井上佐知男*、阿部孝之**、渡辺国昭**
*富山大学大学院理工学研究科
**富山大学水素同位体科学研究センター
〒930-8555 富山市五福3190
Sachio Inoue, Takayuki Abe, Kuniaki Watanabe
Faculty of Science and Engineering, Toyama University
Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930-8555, Japan
Abstract
Atomization, crystallinity, and electrochemical characteristics of powdery NiO treated by mechanical grinding (MG) were examined. XRD analysis and TEM observations showed that MG generated rapid atomization of NiO particles in the initial stage of treatment up to 20 h and further MG resulted in general atomization. Electrochemical measurements showed that the specific capacitance of treated NiO increased with increase in MG time. After 190 h of MG treatment, the specific capacitance was ca. 62 F/g, about 30-times greater than that of an untreated sample. This increment is probably due to the increase in the specific surface area of NiO powder owing to the atomization caused by MG treatment.
研究報告21-5
論文
山崎和也1)、岡部俊夫2)
1)富山大学大学院理工学研究科
2)富山大学理学部
〒930-8555 富山市五福3190
Kazuya YAMAZAKI1), Toshio OKABE2)
1)Department of Science and Engineering, Toyama University Graduate School
2)Department of Physics, Toyama University
Gofuku 3190, Toyama, Japan
Abstract
We tried to make thinning of LiCoO2 crystal grains by atom-milling method for TEM observation, using the Selected Area Diffraction image (SAD), Bright Field image (BF), and High Resolution Electron Microscopic image (HREM). We also analyzed LiCoO2 structural details from these images. These TEM images suggested the coexistence of two-phase in a crystal grain. It was expected that layer structure and Spinel structure coexist on layer (300) and Spinel (844), from the discussion of the crystallographic relationship between the layer structure and the Spinel structure. It is conceivable that this Spinel structure is the same structure as LT-LiCoO2, although we could not observe directly the inter-phase boundary.
研究報告21-6
論文
大石祐一、原正憲*、岡部俊夫**
富山大学大学院理工学研究科
*富山大学水素同位体科学研究センター
**富山大学理学部
〒930-8555 富山市五福3190番地
Y. OISHI, M. HARA*, T. OKABE**
Faculty of Science and Engineering, Toyama University Graduate School
*Hydrogen Isotope Research Center, Toyama University
**Faculty of Science, Toyama University
Gofuku 3190, Toyama 930-8555, Japan
Abstract
Results of transmission Electron Microscopy of expansion of a lattice accompany hydrogen absorption are reported. The icosahedral phase (i phase), the crystal approximant phase (w phase) and the Laves phase in a Ti-Zr-Ni alloy demonstrated hydrogen absorption from the gas phase at a temperature of 300℃ and a pressure of 10 Torr. The i phase, the w phase and the Laves phase remained after the hydrogen absorption, giving a hydrogen atom-to-metal atom ratio ( [H]/[M] ) of 1.14. The rate of expansion of lattice depended on the lattice structure. The rate of expansion of the lattice was analyzed, and it was found that the ability of the w phase to absorb hydrogen is greater that of the i phase. Expansion of a lattice of the i phase and that of the w phase are isotropic. The results indicate that hydrogen is homogeneously distributed.
研究報告21-7
論文
A. Perevezentsev、渡辺国昭、松山政夫、鳥養祐二
UKAEA, Culham Science Centre, Abingdon, OX14 3DB, UK
富山大学水素同位体科学研究センター
〒930-8555富山市五福3190
A. Perevezentsev, K. Watanabe, M. Matsuyama, Y. Torikai
UKAEA, Culham Science Centre, Abingdon, OX14 3DB, UK
Hydrogen Isotope Research Center, Toyama University, Gofuku, Toyama 930-8555, Japan
Abstract
Tritium distribution in stainless steel type 316 exposed to tritium-containing
hydrogen at various temperatures was studied. Sub-surface layer of approx.
20μm thickness enriched with tritium was observed for all samples. This
layer contributes 20% to 40% to overall tritium inventory. Thermal desorption
study reveals that majority of tritium released from the contaminated steel
is in a form of water.
Several method of decontamination, such as purge with various
gases at elevated temperatures and heating with methane-air flame, were
tested. Heating with flame allows removal of largest fraction of tritium
inventory and in shortest period of time among the tested decontamination
methods.
研究報告21-8
論文
鳥養祐二1)、A. Perevezentsev2)、松山政夫1)、渡辺国昭1)
1)富山大学水素同位体科学研究センター
〒930-8555 富山市五福3190
2)UKAEA, Culham Science Centre, Abingdon, OX14 3DB, UK
Y. Torikai1), A. Perevezentsev2), M. Matsuyama1), K. Watanabe1)
1)Hydrogen Isotope Research Center, Toyama University, Gofuku, Toyama 930-8555, Japan
2)UKAEA, Culham Science Centre, Abingdon, OX14 3DB, UK
Abstract
To establish a decontamination method for stainless steel type-316 (SS-316) contaminated by tritium, desorption behavior of tritium caused by heating was examined. When tritium was exposed to a temperature at 523 K for 3 hours, tritium inventories in the SS-316 samples were in the range of 2 to 12 MBq. The tritium depth profiles obtained from BIXS measurements showed that tritium diffused to a depth of more than 70μm. Decontamination test on tritium were carried out at elevated temperatures by purging with commercial argon, argon dried by a getter and argon containing water vapor. The presence of water vapor in the argon atmosphere was found to necessary for tritium decontamination from SS-316 samples. The result suggested that an isotope exchange reaction with water vapor adsorbed on the surface plays an important role in the decontamination of tritium. It was concluded that not only tritium adsorbed on the surface but also that dissolved in the bulk can be removed by heating.