諸住　正太郎（客員教授）
富山大学水素同位体機能研究センター
〒930　富山市五福3190

Shotaro MOROZUMI (Guest Professor)
Hydrogen Isotope Research Center, Toyama University,Gofuku 3190, Toyama 930, JAPAN
(Received July 31, 1991; accepted October 31, 1991)

Abstract
Dissolution, diffusion, and permeation of hydrogen in refractory metals, namely the Va and Ⅵa group metals, are briefly reviewed. Heats of solution for hydrogen in the Va group metals with electron density, e/a, of 5 are about -8 kcal/mol, while those in the Ⅵa group metals with e/a of 6 are about +10 kcal/mol. Heats of solution for hydrogen in the metals, alloyed with other metals to vary the values of e/a ratio, change along a smoothly curved tie line between 4 and 6 of e/a with minor deviations, some of which can be explained in terms of density states at Fermi surface, atomic size effect, and/or lattice distortion. Activation energies for the diffusion and permeation are considered from similar points of view. Isotope effect and hydrogen embrittlement are also described.

一政　裕輔
茨城大学理学部
水戸市文京2-1-1

Yusuke ICHIMASA
Faculty of Science, Ibaraki University,Bunkyo, Mito 310, JAPAN
(Received July 31, 1991, accepted October 31, 1991)

Abstract
For safety handling of tritium, a brief-review is made of tritium intake and its metabolism in the body, as well as its elimination.
  After ingestion or inhalation of tritiated water (HTO), the biological half life of tritium in the body fluid is about 10 days in human subjects. The intake of HTO through the lungs is rapid and almost complete. In the case of low level tritium gas (HT), tritium intake through the skin is extremely low. In contrast, significant tritium intake occurs through the skin which is in touch with metals whose surfaces are already contaminated with tritium and the biological half-life would thus become longer. Intaken HT is oxidized to HTO by intestinal anaerobic becteria. The oxidation rate of HT in man is estimated to be 0.86μCi HTO/l body fluid/HR per 1μCi HT/ml ambient air. Tritium content in the body exposed to HTO vapor is 15000 times than that exposed to HT in the same tritium content in ambient air. In the case of accidental intake of tritium, excretion of tritium is accelerated by either oral intake of 3-4 liter water per day in form of juice, tea, coffee and beer, or by intravenous injection of 5% glucose or Ringer`s solution.

芦田　完^*1、渡辺　道雄^*2、武田　知明^*2、多々　静夫^*2、穴田　博^*2、池野　進^*3、渡辺　国昭^*1
*1富山大学水素同位体機能研究センター
^*2富山大学工学部物質工学科
^*3富山大学地域共同研究センター
〒930　富山市五福3190

Kan ASHIDA^*1, Michio WATANABE^*2, Chiaki TAKEDA^*2,
Shizuo TADA^*2, Hiroshi ANADA^*2, Susumu IKENO^*3,
Kuniaki WATANABE^*1
*1Hydrogen Isotope Research Center, Toyama University
^*2Dept. of Metallurgical Eng., Faculty of Eng., Toyama University
^*3Center for Cooperative Research, Toyama University
Gofuku 3190, Toyama 930, JAPAN
(Received July 31, 1991; accepted October 31, 1991)

Abstract
As a step to understand the kinetics and mechanisms of hydrogen ab/desorption by/from hydrogen storage materials, alloying effects on these processes were studied with mass analyzed thermal desorption spectroscopy, by using a conventional high vacuum system. A binary alloy system of Zr-Al was selected as a model, and deuterium was used as working gas. It was found that the absorption rate of deuterium is proportional to the half power of deuterium gas pressure, and this is remarkably in contrast with other Zr-based alloys such as Zr-Ni and Zr-V-Fe, which obey the first order kinetics. On the other hand, the desorption process obeyed the second order kinetics with respect to the amount of absorbed deuterium atoms, which resemble to other Zr-based alloys. The activation energies for both the absorption and desorption processes were caused to be lowered by increasing the Al content in the alloys. It was also found that the heat of deuterium (hydrogen) solution decreased by increasing Al composition. The ab/desorption mechanisms and alloying effects were discussed in detail by assuming that changes take place in potential surfaces with alloy composition.

三宅　均、松山　政夫、芦田　完、渡辺　国昭、Donald F. Cowgill^*
富山大学水素同位体機能研究センター
〒930富山市五福3190

Hitoshi MIYAKE, Masao MATSUYAMA, Kan ASHISA, Kuniaki WATANABE, Donald F. Cowgill^*
Hydrogen Isotope Research Center, Toyama University,Gofuku 3190, Toyama 930, JAPAN
Tritium Research Laboratory, Sandia National Laboratories ^*Livermore, California 94550, USA
(Received July 31, 1991; accepted October 31, 1991)

Abstract
A simple system using tritium counting and thermal desorption techniques was developed to measure tritium adsorption and/or absorption on/in materials having non-cleaned surfaces and to estimate the tritium inventory/contamination of materials near typical conditions. The samples comprised the materials used for conventional vacuum systems.
  Ad/absorption tritium could be detected as RD (room temperature desorption), SR (surface residuum) and HD (high temperature desorption) species. With respect to organic polymers, only HT molecules dissolved in the samples were responsible for the RD, SR and HD. As for other materials, however, the RD species was revealed to be physically adsorbed HTO. The HD species formed a peak at about 460K for each material except organic polymers. It appeared to be adsorbed tritium, but desorbed as a condensable gas at liquid nitrogen temperature. It was, however, not soluble in water. Its chemical forms and formation mechanisms were left as open question. The SR species appeared to be a part of HD.
  The order of adsorption amounts was as follows: [Epoxy resin, FRP (Fiber reinforced plastics)] > [Ni (Nickel)] > [Cr (Chromium), Fe (Iron), SS304 (Stainless steel), A2219 (Aluminum alloy)] > [h-BN (Boron nitride), SiC (Silicon carbide), ASS (SS304 passivated by anodic oxidation layers), BSS (SS304 passivated by h-BN segregation layers)]. This order was considerably different from that observed for clean surfaces. In addition, the adsorption amounts for metals/alloy were about two orders of magnitude smaller than those reported for clean metal surfaces. This discrepancy in results in apparently due to the presence of oxides and contamination layers over the samples used. Nevertheless, it was found that the passivation of SS304 with anodic oxidation and/or h-BN segregation layers should be quite valid to decrease the tritium inventory and/or contamination on/of the material walls of tritium handling systems.

松山　政夫、渡辺　国昭、諸住　正太郎

富山大学水素同位体研究センター
〒930　富山市五福3190

Masao MATSUYAMA, Kuniaki WATANABE, Shotaro MOROZUMI
Hydrogen Isotope Research Center, Toyama University,Gofuku 3190, Toyama 930, JAPAN
(Received July 29, 1991; accepted October 31, 1991)

Abstract
Reliable techniques for storage, supply and recovery of tritium gas are indispensable to ensure safe handling of amounts of tritium. From this viewpoint, we made a tritium container packed with Zr₉Ni₁₁ alloy (1.5g) in order to examine its feasibility by using deuterium gas an alternative of tritium. This container was made of 316 stainless steel with double containment concept and equipped with a handmade ohmic heater. This heater was able to elevate the temperature of the container up to 500℃will small power of 65 W. The as-received Zr₉Ni₁₁ alloy used consisted of a mixture of intermetallic compounds such as ZrNi, Zr₉Ni₁₁ and Zr₇Ni₁₀. It was easily activated with vacuum heating at 400℃ for 1 hr. It was revealed that the container is applicable to supply tritium gas of about 1 atm at 350℃ and to recover it with considerably high absorption rate at room temperature. Apparent absorption rate, however, has significantly been affected by desorption of the deuterium ad/absorbed on/in the inner tube of the container.

松山　政夫、荒井　寛幸^*、山崎　登志成^*、渡辺　国昭

富山大学水素機能研究センター
^*富山大学工学部
〒930富山市五福3190

Masao MATSUYAMA, Hiroyuki ARAI^*, Toshinari YAMAZAKI^*, Kuniaki WATANABE

Hydrogen Isotope Research Center, Toyama University
^*Faculty of Engineering, Toyama University
Gofuku 3190, Toyama 930, JAPAN
(Received July 31, 1991; accepted October 31, 1991)

Abstract
To develop some in-situ measurement techniques of high level tritium, the basic characteristics of a silicon-avalanche photodiode (Si-ARD) were examined in detail using low energy X-ray emitters. We also investigated the applicability of the Si-APD to measurements of low energy bremsstrahlung X-rays caused by interactions between materials and the β-rays of tritium. The Si-APD worked well at room temperature without using any particular cooling device, and it proved to be satisfactory for the measurements of low energy X-rays below 20 keV except for significant temperature dependence of the peak energy in observed spectra, which is considered as its inherent characteristic on the one hand and owing to temperature dependence of the leakage current of the Si-APD on the other. In addition, the bremsstrahlung X-ray spectra measured using a polymer tritium source and tritium gas showed a broad single peak in the region below 15 keV. It has been revealed that the Si-APD is valuable for fabricating a compact detector system capable of detecting low energy bremsstrahlung X-rays and its easy in maintenance.

長谷川　淳、伏間江　弘、松山　政夫、渡辺　国昭

富山大学工学部
富山大学水素同位体機能研究センター
〒930　富山市五福3190

Masao MATSUYAMA, Hideo NAKATANI^*, Toshinari YAMAZAKI^*, Kuniaki WATANABE

Kiyoshi HASEGAWA, Hiroshi FUSUMAE, Masao MATSUYAMA, Kuniaki WATANABE
Faculty of Engineering, Toyama University
Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930, JAPAN
(Received July 31, 1991; accepted October 31, 1991)

Abstract
The kinetics of the UV-stimulated HT oxidation in oxygen atmosphere has been studied in combination with computer simulation, where 30 elementary reactions were considered. The rate of HTO formation was observed and proved to be proportional to the pressure of O₂ and the fraction of HT with respect to total hydrogen pressure, (H₂+HT), and 1/2 order to the total hydrogen pressure. The simulation resulted in the same pressure dependence as the observed one. The contributions of the elementary reactions to the HTO formation were calculated, assuming steady states for intermediates species. It has been revealed that the HT oxidation is initiated by photolysis of O₂ to O(³P) (λ<242nm) and subsequently the formed O₃ and OH play important roles in the HTO formation. The paths were examined in detail with computer simulation.

林　秀治、金坂　績
富山大学理学部
〒930　富山市五福3190

Hideharu HAYASHI, Isao KANESAKA

Faculty of Science, Toyama University
Gofuku 3190, Toyama 930, JAPAN
(Received July 31, 1991; accepted October 31, 1991)

Abstract
The infrared spectrum of T₂O ice has been discussed from the viewpoint of its stability on a film, whose structure was transferred from amorphous ice, Ia, into cubic ice at 90K within 10 minutes after forming such a film. A new infrared cell for Ice-Ia was made, where the KRS-5 plate for a T₂O film was held by in/on the circular tube stored in liquid N₂. In cold runs it was confirmed that the cell was quite useful for ice-Ia, whose structure was kept in 6 hours even if He gas at about 2 Torr was added into the cell.

三宅　均、芦田　完、松山　政夫、渡辺　国昭

富山大学水素同位体機能研究センター
〒930富山市五福3190

Hitoshi MIYAKE, Kan ASHIDA, Masao MATSUYAMA, Kuniaki WATANABE

Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930, JAPAN
(Received July 31, 1991; accepted October 31, 1991)

Abstract
We designed an experimental system capable of handling at least 100 Ci tritium in an experimental run: the amount is considered to be necessary for a variety of experiments aiming at investigating the physicochemical properties of tritium. As a first step, we fabricated one of its subsystems, tritium circulation subsystem, in order to examine pumping and out gassing characteristics of the subsystem as well as the potential of Zr-based alloys for the storage and recovery of about 1000 Ci of tritium.
  It has been observed that the combination of a mechanical roughing pump and sorption pump could evacuate the subsystem down to 1x10^-6 Torr. It was suggested, however, that the adsorption and desorption of HTO on/from the inner wall of tritium systems would cause serious problems on safety and environmental aspects as well as pumping characteristics, requiring thus the development of surface coating layers to protect the wall from tritium adsorption and/or adsorption.