金　瑩、原　正憲、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

Y. Jin, M. Hara, K. Watanabe

Hydrogen Isotope Research Center, Toyama University
Gofuku3190, Toyama 930-8555, JAPAN

Abstract

　Absorption of protium and deuterium by Pd, Pd-4at%Pt and Pd-8at%Pt powders under 200 mesh was measured in a dilute hydrogen concentration region at temperatures from 0 to 82℃ by recording the decline of hydrogen pressure in an experimental chamber due to hydrogen absorption. These measurements and data analyses gave the adsorption rate, desorption rate and diffusion constants of hydrogen isotopes for the alloys. The absorption was very fast, completed within a few tens of seconds, but there appeared a clear trend of decreases in the rate constants for adsorption, desorption and diffusion with increase in the Pt content in the sample. The activation energies for these rate processes increased with increase in the platinum content. Regarding isotope effects, protium showed a higher adsorption rate but lower desorption rate in the present temperature range. It was also found that protium diffused more slowly than did deuterium in all three samples

原　正憲，川野　滋久，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

Masanori HARA, Shigehisa KAWANO and Kuniaki WATANABE

Hydrogen Isotope Research Center, Toyama University
Gofuku3190, Toyama 930-8555, JAPAN

Abstract

　Pressure-composition isotherms for Pd-Rh alloys, in which the Rh contents were 4, 8 and 10 atomic % to hydrogen isotopes, were measured for the pressure range 103 < p < 106 Pa and for the temperature range 273 < T < 453 K. All of the isotherms showed wide plateaus, the widths of which remained constant despite changes in the Rh content. The thermodynamics of Pd-Rh hydride (deuteride) were investigated using the plateau pressure. The enthalpies for hydride (deuteride) decomposition decreased with increase in Rh content. The entropies, however, were kept almost constant. In addition, the hydrides were  more stable than the deuterides.

安田祐介・古城将彦・千葉晋平

富山大学理学部、富山市五福

Yusuke YASUDA, Masahiko FURUKI, and Shinpei CHIBA

Faculty of Science, Toyama University, Toyama 930-8555

Abstract

A frequency response (FR) method was applied to a hydrogen/hydrogen-storage alloy system. The FR data were analyzed on the basis of two models consisting of two or three rate processes: (i) X↔A↔C and (ii) X↔A↔B↔C, where X denotes a hydrogen molecule in the gas phase, A is a hydrogen molecule (or atom) adsorbed on the surface, B is atomic hydrogen adsorbed on the surface, and C is atomic hydrogen absorbed in the lattice. Rate coefficients at every rate process in the model were evaluated by computer simulation. It was concluded that this FR method is useful for characterizing valid hydrogen storage alloys, because both the rate coefficients concerned with adsorption-desorption and also diffusion occurring in series can be determined.

T. Ma, Y. Hatano, T. Abe, K. Watanabe

Hydrogen Isotope Research Center, Toyama University
Gofuku3190, Toyama 930-8555, JAPAN

Abstract

　Two groups of Pd-modified MgNi samples were prepared: sample Ⅰ, ball-milling Pd (1, 6 and 10 mol%) with amorphous MgNi for 10 min, 2hr or 10 hr, sample Ⅱ, ball-milling 10 mol% Pd with Mg₂Ni and Ni for 80 hr. Effects of the addition of Pd on the electrochemical properties of MgNi were investigated. For sample Ⅰ, the effects of Pd depended on both the Pd ratio and the time of ball-milling. During ball-milling, Pd bebame amorphous and was distributed uniformly on the surface of MgNi particle. At 6 mol% and 10 mol% Pd, degradation of the discharge capacity of MgNi was significantly decreased. As for sample Ⅱ, the cycle life of MgNi was remarkably improved by Pd modification. The roles of Pd in the behavior of MgNi were analyzed, and the improvements in MgNi properties arising from both modifications by Pd were thought to be due to the prevention of the formation of Mg(OH)₂.

高森美幸、波多野雄治、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

Miyuki Takamori, Yuji Hatano and Kuniaki Watanabe

Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930-8555, Japan

Abstract

　The correlation between microstructure of tungsten and rate of carbide formation was investigated at 800 ℃ by examining the reaction between amorphous carbon films and tungsten specimens fabricated under different conditions. The carbide formed was W₂C, and no WC was observed. The growth rate of W₂C showed no significant dependence on the size and shape of crystal grains. A clear correlation, however, was observed between the hardness of tungsten and the rate of W₂C growth, and the reaction rate decreased with hardness.

松山　政夫、鳥養　祐二、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

Masao Matsuyama, Yuji Torikai and Kuniaki Watanabe

Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930-8555, Japan

Abstract

　The  b-ray-induced X-ray spectra observed for a polymer disk (1 mm thickness), which was made of poly-methylmethacrylate labeled with tritium, were analyzed and they were reproduced by computer simulation based on the uniform distribution of tritium in the polymer disk. The X-ray spectra were measured in both helium and argon atmospheres. An X-ray spectrum observed in the helium atmosphere consisted of only a broad bremsstrahlung X-ray peak, while in the argon atmosphere a characteristic X-ray peak appeared in addition to bremsstrahlung X-rays. From differences in the shape and intensity of X-ray spectra observed in both atmospheres, the conversion fraction of the bremsstrahlung X-rays to the characteristic X-rays in an argon atmosphere was determined to be 7.1x10^-2 by taking the absorption coefficient of X-rays into account. The spectra observed in both atmospheres could be reproduced quite well by using the equations to estimate generation and attenuation of X-rays in various materials. It was suggested, therefore, that a tritium depth profile in carbonaceous materials can be evaluated by the numerical simulation. Furthermore, the simulation indicated that nitrogen could be also used as a promising alternative gas of helium for evaluation of a tritium depth profile in bulk.

鳥養祐二¹⁾，松山政夫¹⁾，渡辺国昭¹⁾, 野田信明²⁾, N. Bekris³⁾, M. Glugla³⁾, V. Philipps⁴⁾, P.Code⁵⁾

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) 核融合科学研究所 〒509-5292 岐阜県土岐市下石町322-6
3) Tritium Laboratory, Forschungszentrum Karlsruhe, D-76021 Karlsruge, Germany
4) EURATOM Association, Forschungszentrum Jülich, Institute for Plasma Physics, TEC, 52425, Jülich, Germany
5) EURATOM/UKAEA Fusion Association, Culham Science Center, Abingdon, OX14 3DB, UK

Y. Torikai¹⁾, M. Matsuyama¹⁾ K. Watanabe¹⁾, N. Noda²⁾, N. Bekris³⁾, M. Glugla³⁾,V. Philipps⁴⁾, P.Code⁵⁾

1) Hydrogen Isotope Research Center, Toyama University, Gofuku, Toyama 930-8555, Japan
2) National Institute for Fusion Science, Orishi-sho, Toki-shi, Gifu 509-8292, Japan
3) Tritium Laboratory, Forschungzentrum Karlsruhe, D-76021 Karlsruge, Germany
4) EURATOM Association, Forschungszentrum Jülich, Institute for Plasma Physics, TEC, 52425, Jülich, Germany
5) EURATOM/UKAEA Fusion Association, Culham Science Center, Abingdon, OX14 3DB, UK

Abstract

　In this study, a simple and easy method of PIN-diode was used to measure the tritium inventory in a tritium-contaminated sample. The results of measurements of X-ray intensities of after being shielded by Al and plastic sheets by PIN-diode method corresponded well to the results by a conventional Ge-semiconductor detector method. The surface distributions at JET Mark IIA type divertor tiles were obtained by using the PIN-diode method that demonstrated a high effectiveness in determining the tritium inventory.