研究報告　-　1巻　(1981年)

解説 - Review

1-1

富山大学におけるトリチウムの研究（1956〜1981）
Summary of Studied of Tritium at Toyama University （1956〜1981）

竹内　豊三郎

Toyasaburo TAKEUCHI

論文 - Original

1-2

トリチウム取扱い装置の設計、製作、および、その性能試験
Design, Construction and Tritium Clean-up Examination of a Tritium Handling System

松山　政夫、三宅　均、芦田　完、渡辺　国昭、竹内　豊三郎

Masao MATSUYAMA, Hitoshi MIYAKE, Kan ASHIDA, Kuniaki WATANABE, Toyosaburo TAKEUCHI

1-3

熱分解黒鉛と重水素イオンの化学的相互作用
Chemical Interactions between a Pyrolytic Graphite and Ion-implanted Deuterium

芦田　完、市村　憲司、松山　政夫、三宅　均、渡辺　国昭

Kan ASHIDA, Kenji ICHIMURA, Masao MATSUYAMA, Hitoshi MIYAKE, Kuniaki WATANABE

1-4

テフロン膜における水素同位体および不活性気体の透過と拡散
Diffusion and Permeation of Hydrogen Isotopes and Inert Gases in/through Tetrafluoroethylene

三宅　均、松山　政夫、芦田　完、渡辺　国昭

Hitoshi MIYAKE, Masao MATSUYAMA, Kan ASHIDA, Kuniaki WATANABE

1-5

熱拡散法によるトリチウムの濃縮 −　TH-H₂, TD-D₂, T₂-⁴Heの系　−
Enrichment of Tritium by Thermal Diffusion −　TH-H₂, TD-D₂, T₂-⁴He Systems　−

高安　紀、牧野　郁朗、扇谷　一彦、高木　正年、竹内　豊三郎

Osamu TAKAYASU, Ikuro MAKINO, Kazuhiko Ohgiya, Masatoshi TAKAGI, Toyosaburo TAKEUCHI

1-6

走査型電子顕微鏡によるCu-Ni表面のトリチウムの分布の観察
Autoradiographical Detection of Tritium in Cu-Ni Alloy by Scanning Electron Microscopy

高安　紀、中野　美樹、竹内　豊三郎

Osamu TAKAYASU, Yoshiki NAKANO, Toyosaburo TAKEUCHI

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研究報告1-1
解説

  The chemical studies of tritium have been continued for 25 years at the laboratory of physical chemistry Toyama University, since the first supply of tritium from AERE in 1956. The initial study on tritium was to establish the measurement of β-ray of tritium by the modification of 2π counter. Then the isotope effect of tritium for the desorption from nickel powder was investigated at -183℃ and 120℃. The study was then followed by the elucidation of the reactivity of adsorption hydrogen on nickel for the hydrogenation reaction of ethylene adapting the differential isotope kinetic method.
  The simultaneous measurement of tritium and radioactive carbon ¹⁴C was investigated by means of a gas proportional counter using the energy spectrum of these isotopes. A mixture of tritium and ¹⁴C-carbon dioxide was used as the sample. Two types of counter tubes of different diameter sizes and two kinds of filling gas, methane and buthane, were used. It was advantageous for the distinction between the energy spectrum of tritium and ¹⁴C that maximum range of the β-rays of tritium was shorter than the diameter of the counter tube. The amounts of both isotopes in the mixed gas could be determined with an error of 5%, when methane was used as the filling gas and with in 3% when buthane was used.
  The effect of the α-particle irradiation on the adsorption of tritium on nickel plate and on nickel film prepared by evaporation was investigated. The change in the amount of adsorbed tritium was detected by means of autoradiography. The irradiation of α-particles increased in the case of the nickel plate, but decreased in the case of the evaporated film. These results were interpreted in terms of the change in the active sites made of lattice imperfections. The similar studies were carried out on copper, nickel, and copper-nickel alloys employing massive metals and evaporated films formed on glass. The results showed that not only the amount of adsorption of tritium but also the reactivity of the adsorbed tritium for ethylene were strongly influenced by the irradiation of α-particles, especially in the range of alloy composition.
  The effects of lattice imperfections produced by ⁶Li(n,α)³H reaction upon the catalytic activities in the hydrogenation reaction of ethylene on powdered copper, nickel, and copper-nickel alloys, which had previously been doped with lithium and irradiated with thermal neutrons were investigated. In addition, the amount of tritium taken from these powder was measured by placing it in contact with normal hydrogen and raising temperature of the powder. The irradiation of neutrons increased the activities of nickel and copper-nickel by 3-4 times, but did not affect the activity of copper. The dependence of the amount of tritium upon the composition of the powder was very similar to that of the catalytic activity, suggesting that the diffusion of tritium from the interior is the rate-determining step.
  The behavior of tritium produced by ⁶Li(n,α)³H reaction in the catalytic hydrogenation of ethylene was investigated by autoradiographs using copper, nickel and copper-nickel alloy plates. These plates were preliminarily covered with lithium by evaporation and irradiated with neutrons. The autoradiogrphs given by the striping-film method indicated that the grain boundaries which were not used in the catalytic reaction exhibited a much stronger radioactivity due to the tritium than did the grain; on the other hand, these which were used in the catalytic reaction behaved in just the opposite way. The electron-microscope autoradiographs indicated that tritium accumulated preferentially on the step edges of the slip-band of the crystal. The electron micrographs indicated numerous micro-holes which would correspond “depleted zone”, an unstable intermediate stage in the formation of displacement spikes and thermal spikes.
  The chemical behavior of dissolved tritium in iron, copper, and iron-copper sheets in the Fisher-Tropsch reaction was investigated. The amount of preadsorbed tritium on the surface of iron and iron-copper sheets markedly increased, about 10 times, due to the addition of carbon monoxide to the surface. The dissolution of tritium in these sheets prevented by preadsorbed carbon monoxide.
  The ability of trapping of tritium by silica and alumina which were preliminarily doped with lithium and irradiated with thermal neutrons and the removal of tritium from these materials by the reaction with ethylene were investigated. Tritium formed in alumina was not liberated by the elevation of temperature to 350℃. Tritium in silica was very slightly liberated at above 250℃. Tritium in silica removed in the form of tritiated ethane at 300℃ and that in alumina at 100℃. The doping of 10% nickel to alumina and silica promoted the liberation of tritium gas and the formation of tritiated compounds.
  The enrichment of tritium in water by means of the reaction of tritiated water with Raney-Ni alloy was investigated. Tritiated water was contacted with the alloy in the presence of sodium hydroxide, then the temperature was stepwisely raised to 1000℃. It was found that the concentration of tritium in hydrogen gas released from the sample was very low at the temperature range from 20℃ to 300℃, and that hydrogen gas contains 6 times higher level tritium was generated at about 600℃.

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研究報告1-2
論文

A tritium handling system composed of a special type of glove boxes and a tritium decontamination system was designed and constructed for safety handling of tritium gas up to 5Ci/day. The performance of the decontamination system and the surface contamination of a glove box were examined with an as received tritium gas which contained tritiated methane about 10%.
  Copper oxide (CuO) and/or alumina-supported platinum (Pt/Al₂O₃) were used as catalysts for oxidation of the tritium gas. It was found that the conversion of T₂ was nearly unity above 400℃on CuO, however the conversion of T-CH₄ was very low even at 500℃. On the other hand, Pt/Al₂O₃ showed sufficient capability for the removal of T-CH₄ above 400℃. The results indicate that the system can decontaminate both tritium and tritiated methane to the amount of 5Ci to the background level within five hours when equal amount (in volume) of the CuO and the Pt/Al₂O₃ are packed in the catalyst bed and used above 400℃. It was also found that the contamination of the inside surfaces of the glove box was not significant throughout the cleanup examination when they were exposed to the tritium gas in dry atmosphere. However, significant contamination took place in the specimen water which was placed in the glove box and exposed to the tritium gas during the cleanup examination.

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研究報告1-3
論文

Pyrolytic graphite is one of the candidate materials for the first wall of the controlled thermonuclear reactors. Tritium recycling in graphite is one of the important problems for applying the graphite to the first wall. In order to investigate the fundamental processes of the recycling ions (5keV) were implanted into a pyrolytic graphite and chemical states of the implanted deuterium were investigated by means of X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS).
  In SIMS spectra, molecular ions such as CD^±, CD₂⁺, CD₃⁺, C₂D^- appeared due to the implantation. No molecular ions above C₃-group was detected. XPS measurements revealed that C1s peak gradually shifted to higher energy side approaching to a constant value (0.4eV) with the increase of the incident deuterium-ion fluency. The results indicate that a part of deuterium implanted into the graphite binds chemically with the carbon atoms and the deuterium exists as C₂-D or C-D in the graphite.

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研究報告1-4
論文

Permeation rates and diffusion contests of hydrogen isotopes (H₂, D₂, T₂) and inert gases (He, Ne, Ar, Kr, Xe) were measured for tetrafluoroethylene at room temperature by means of the time-lag method, and the solubilities were evaluated. The diffusion constants of hydrogen isotopes decreased with their masses, while the relative values of the diffusion constants deviated from the square root of inverse mass ratio. Solubilities of hydrogen isotopes were increased with their masses. The diffusion constants and the solubilities of inert gases showed identical tendencies as the hydrogen isotopes: the diffusion constants of helium was the largest and the solubility was the smallest among them.
  It was found that the diffusion constants and the solubilities of the inert gases were exponential functions of the heat of vaporization of each gas, while those for hydrogen isotopes deviated from relations beyond experimental errors.

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研究報告1-5
論文

The enrichment of tritium which was mixed with H₂, D₂, or He was studied by means of thermal diffusion cylindrical columns. Four cylindrical columns with different diameters were used in this study. A gas reservoir was connected to each column in order to increase the separation efficiency. The temperature of the inner heater was changed over a range from 200℃to 450℃ keeping the column at 20℃. The results showed that the maximum equilibrium separation factor for TH in H₂ was 17, that for TD in D₂ was 4.5, and that for T₂ in He was 18. The optimum distance between the inner heater and the cooled wall was estimated by a modified Waldmann's equation.

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研究報告1-6
論文

The autoradiograph of tritium dispersed in Cu-Ni alloy sheet by ⁶Li(n,α)³H reaction was obtained by a scanning electron microscope. Prior to the irradiation of neutrons ⁶Li was deposited on the sheet by evaporation. The liquid emulsion, Fuji-ER, was used in this study. The distribution of tritium was detected by the dispersion of silver grains remaining in the emulsion after the development was carried out.
  It was shown that the silver grains accumulated preferentially along grain boundaries. The width of the lines of silver grains is very small (less than 1/10) in comparison with that obtained by the stripping method.