Kan Ashida^a, Masao Matsuyama^a, Kuniaki Watanabe^a, Hiroshi Kawamura^b, Etsuo Ishitsuka^b

^a Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Toyama 930, Japan

^b Japan Atomic Energy Research Institute, Oarai Research Establishment, Oarai-Machi, Higashi Ibaraki-gun, Ibaraki 311-13, Japan

Absrtract

    With respect to the impurity emission and erosion of a Be first wall, a secondary ion mass spectrometric investigation was carried out along with surface characterization with X-ray photoelectron spectroscopy. It was found that Be is emitted as distinct types of chemical from the surface owing to sputtering with Ar⁺ and an (Ar⁺ + D⁺₂) mixture: (i) Be and Be-cluster, (ii) oxide and hydroxide, and (iii) hydride and/or deuteride.

Toyosaburo Takeuchi^a, Atsuo Mori^b, Masao Matsuyama^a, Osamu Takayasu^b

^a Hydrogen Isotope Research Center, Toyama University, Toyama 930, Japan

^b Faculty of Science, Toyama University, Toyama 930, Japan

Abstract

    The separation of tritium from tritiated water (3.8 and 380 MBq/mol) was studied by leaching of various Raney alloys, Al-Ni, Al-Co, Al-Cu (1:1), and powdered Al, with NaOH solution of tritiated water. Diluted T-hydrogen gas, about 1/10 of the original tritiated water, was released by the leaching. Remarkably enriched T-hydrogen (about 100 times the level of the original T-water) was released when the leached alloy-residue was heated to >300℃. The stoichiometrical deficiency of Al in Raney alloy to NaOH expressed by the following equation increased the efficiency of the enrichment. Al + NaOH + H₂O→ NaAlO₂ + 3/2H₂. Powdered Al gave dilute T-hydrogen but no enriched T-hydrogen from the residue, though the temperature was elevated to 100℃.
    The results showed that the leaching reaction of Raney alloys is available for the enrichment and recovery of tritium from tritiated water. Two reaction mechanisms for the enrichment are proposed.

K. Watanabe, M. Matsuyama

Hydrogen Isotope Research Center, Toyama University, Toyama 930, Japan

Abstract

    This paper briefly reviews the recent development on the measurement of high concentration tritium required for thermonuclear fusion devices such as small ionization chamber, bremsstrahlung counting and fluorescent counting methods. The former two are promising for in-situ measurement of tritium in the range from 1x10^-6 to 2.7 Ci/cm³ (=1 atmospheric pressure). The last one is excellent for a higher concentration range. As for the gas analysis, infrared absorption and laser Raman spectroscopies are revealed to be excellent for gas analysis up to one atmospheric pressure. Problems to be solved in near future are also discussed.

Kuniaki Watanabe, Masao Matsuyama, Toshinari Yamazaki

Hydrogen Isotope Research Center,  Faculty of Engineering, Toyama University, Gofuku 3190, Toyama 930, Japan

Abstract

    Accuracy and reliability of a small ionization chamber and a bremsstrahlung X-ray counter have been examined by using three kinds of tritium gases. The ratio of tritium concentration in T₂-gas to that in HT-gas measured by bremsstrahlung counting method agreed quite well with the concentration ratio determined from mass spectrometer. On the other hand, the ration between DT- and HT-gases was about 10% higher by the ionization chamber as well as the bremsstrahlung counting method than that evaluated with the mass spectrometer. This discrepancy could be understood to be due to hydrogen contamination of the DT-gas and rather poor resolution of the mass spectrometer used.

Keywords: high concentration tritium; small ionization chamber; bremsstrahlung X-ray counter; mass spectrometer; D-T fuel processing

Kiyoshi Hasegawa^a, Hiroshi Fusumae^a, Shoichi Miyahara^a, Manabu Shinohara^a, Masao Matsuyama^b, Kuniaki Watanabe^b

^a Chemical and Biochemical Engineering, Faculty of Engineering, Toyama University, Gofuku 3190, Toyama 930, Japan

^b Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Toyama 930, Japan

Abstract

    The effects of air pollutants on UV-stimulated HT oxidation were studied by selecting CCl₄ as a model pollutant. Mixture gases consisting of H₂ + HT, O₂ and CCl₄ were irradiated with a high pressure mercury lamp. The reaction products were found to be HTO and TCl. The role of CCl₄ was evaluated by measuring the formation rate of HTO + TCl as a function of the partial pressure of CCl₄. The reaction took place in two stages. During the first stage, the extent of the reaction increased almost linearly with time. During the second stage, the rate became faster with time, showing a similar feature to autocatalytic reactions. It was found that those rates were considerably increased with the pressure of CCl₄. In the case of 1.0 Torr, the rate of the first stage was 60 times greater than that of the UV-stimulated HT oxidation previously reported, and that of the second stage was about 10 times that of the first stage. As a whole, the CCl₄-assisted UV-stimulated HT oxidation showed a 5×10⁴ -5×10⁵ times greater reaction rate than the β ray-induced radiochemical HT oxidation.
    With the aid of computer simulation including 47 relevant elementary reactions, the enhanced acceleration of the reaction was understood as a result of the formation of new reaction paths such as Cl → H → HO₂→ H₂O and Cl → H → HO₂→ OH → H₂O, which lacked in the UV-stimulated HT oxidation mechanism.

Keywords: tritium; oxidation; tritiated water; UV-irradiation; carbon tetrachloride; acceleration effect; autocatalytic effect

渡辺国昭

K. Watanabe

Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Japan

Abstract

    The study of tritium-material interaction is a key for the safe handling of a large amount of tritium in thermonuclear fusion reactors. Tritium data are vital to understand the nature of tritium-material interaction and to predict tritium behavior in reactor systems. Studies of isotope effects are also required to utilize hydrogen/deutrium data. Another importance of tritium study is to make clear radiological phenomena: namely, emission of b-rays and x-rays, production of ³He and their effects. The present paper reviews the recent status of tritium-material interaction studies in Japan.

Keyword: tritium; material interaction; Japanese activity; isotope effect; b-rays; X-rays; helium