発表論文 2005年


Influence of microstructure of tungsten on solid state reaction rate with amorphous carbon film

Y. Hatanoa, M. Takamoria, K. Nogitab, K. Matsudac, S. Ikenoc, K. Watanabea

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

bDivision of Materials Engineering, The university of Queensland, Brisbane, Qld 4072, Australia

cDepartment of Material Systems Engineering and Life Science, Faculty of Engineering, Toyama University, Gofuku 3190, Toyama 930-8555, Japan


    Plate-type speciments were cut from three different types of tungsten sheets fabricated under distinct rolling and heat treatment conditions in the directions parallel or perpendicular to the rolling planes. Amorphous carbon films were prepared by vacuum deposition on the specimen surfaces. Then, the specimens were heated at 1073 K in vacuum, and reaction products were analyzed by means of X-ray diffraction. The carbide formed was W2C and no peak of WC appeared. The growth rate of W2C was independent of the cutting directions of the specimens, although the grain boundary densities at the specimen surfaces were quite different. On the other hand, the rate of W2C growth was dependent on both reduction and heat treatment conditions, and a specimen with higher hardness showed a higher growth rate. By taking account of the observations by a transmission electron microscope, it was concluded that dislocations play important roles in W2C growth.


Helium irradiation effects on retention behavior of deuterium implanted into boron coating film by PCVD

H. Kodamaa, M. Oyaidzua, A. Yoshikawaa, H. Kimuraa, Y. Oyab, M. Matsuyamac, A. Sagarad, N. Nodad, K. Okunoa

aRadiochemistry Research Laboratory, Faculty of Science, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan

bRadioisotope Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan

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

dNational Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan


    Helium irradiation effects on the retention of energetic deuterium implanted into the boron coating film were investigated by means of X-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS). It was found, by XPS, that the B 1s peak was shifted to lower binding energy side by He+ ion irradiation and the FWHM was extended. These facts show that the some defects were introduced into the boron coating film by He+ ion irradiation. From TDS experiment, the deuterium retention, especially the amount of B-D terminal bond, increased by the pre-He+ ion irradiation. However, it decreased by the post-He+ ion irradiation. These experimental results indicate that the B-D terminal bond was mainly influenced by the He+ ion irradiation because the two neighbor B-D bonds have to dissociate simultaneously for the B-D-B bridge bond.

[2005_03 ]

Effects of bulk modification by Pd on electrochemical properties of MgNi

Tiejun Ma, Yuji Hatano, Takayuki Abe, Kuniaki Watanabe,

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


    An amorphous MgNi alloy was prepared by ball-milling of Mg2Ni and Ni with 10 mol% of Pd for 80 h, and effects of the bulk modification by Pd on the electrochemical properties of amorphous MgNi were investigated by using a conventional two-electrode system. It was found through X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM) analyses that Pd dissolved uniformly into the bulk of MgNi during the ball milling without affecting the amorphous structure of MgNi. As a result, the cycle life of Pd-modified MgNi in alkaline solution was significantly improved. HRTEM and XRD observations showed that a dense layer of fine grains of Mg(OH)2 covered over the surface of unmodified MgNi powder after the immersion in alkaline electrolyte solution, whereas no appreciable extent of Mg(OH)2 formation was observed on the Pd-modified MgNi powder. These observations demonstrate that the Pd bulk modification is very effective to suppress the formation of Mg(OH)2 layer and hence gives rise to the remarkable improvement of the cycle life of the electrode.


Surface Segregation of Ti in a V-4Cr-4Ti Alloy and Its Influence on the Surface Reaction Rates of Hydrogen Isotopes

Yuji Hatanoa, Ryo Hayakawaa, Kanako Nishinob, Susumu Ikenob, Takuya Nagasakac, Takeo Murogac, Kuniaki Watanabea

aHydrogen Isotope Research Center, Toyama University, Toyama 930-8555, Japan

bDepartment of Material Systems Engineering and Life Science, Faculty of Engineering, Toyama University, Toyama 930-8555, Japan

cNational Institute for Fusion Science, Toki 509-5292, Japan


    The change in the chemical surface state of a V-4Cr-4Ti alloy after heat treatments in vacuum at temperatures from 573 to 1273 K was investigated by means of X-ray photoelectron spectroscopy. Before heating, the surface of the as-polished alloy was covered with a V oxide film. Diffusion of oxygen into the bulk started at around 673 K, and the alloy surface gradually became metallic. Oxygen, however, did not disappear from the surface completely. Surface segregation of Ti was observed as the temperature increased. The concentration of Ti reached 20 at% at 1273 K. No significant segregation of Cr or other impurities were observed. This surface segregation of Ti significantly reduced the surface reaction rates of H2 and D2. The isotope effect on the surface reaction rates of H2 and D2 was not observed under the present experimental conditions.


Hydrogen absorption capability of a niobium panel for pumping neutral atoms in divertor region

Y. Nakamuraa, A.I. Livshitsb, Y. Nakaharac, Y. Hatanod, A. Busnyukb, N. Ohyabua

aNational Institute for Fusion Science, 3226-Oroshi-cho, Toki, Gifu 509-5292, Japan

bBonch-Bruyevich University, 61 Moika, St. Petersburg 191186, Russian Federation

cJapan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195, Japan

dHydrogen Isotope Research Center, Toyama University, Toyama 930-8555, Japan


    The capability of a niobium panel to absorb atomic hydrogen was investigated for particle control application in divertors. The absorption rate (1.3 × 1020 H/m2s) stayed almost constant up to a dose of 4 × 1023 H/m2 with no hydride formation occurring. The absorption panel can be easily regenerated. The absorbed hydrogen can be retained in the panel even after 48 h at room temperature. The absorption rate was found to decrease with panel temperature for T < 200 °C, remarkably dropping in the vicinity of room temperature. This is connected most probably with the formation of a multilayer impurity coverage. The multilayer carbon coverage deposited during the panel exposure in the divertor region of LHD decreased the absorption rate, but the panel properties could be completely restored by heating at 850 °C in spite of panel carbidization.


水素エネルギー関連材料 水素エネルギー社会の実現に向けて

波多野雄治a, 井上光浩a, 阿部孝之a, 中森裕子b, 折茂慎一b, 長崎正雅c

a富山大学, b東北大学, c名古屋大学


    水素は、環境汚染物質を排出しない理想的な燃料として、その利用技術の開発研究が世界的に、 かつ急ピッチで進められており、「水素エネルギー社会」という言葉も頻繁に耳にするようになってきた。 「水素エネルギー社会」において原子力をどう位置づけるかは、エネルギー供給における原子力の役割を考える上で重要な 問題である。すでに2001年および2002年の日本原子力学会「春の年会」において「総合報告」の形で重要な研究発表と活発な討論が なされているが、水素エネルギー分野の技術開発は日進月歩で進んでおり、さまざまな場所で継続的に議論する必要がある。
    水素の燃料としての最大の難点は、周知のように、利用可能な状態(すなわちH2の状態)では 天然にはほとんど存在せず、天然ガスや石油、メタノール、水などの原料から製造しなければならないということである。 水素エネルギーシステムの燃料資源量や環境汚染物質排出量は、どの原料から、どのような手段で水素を製造するかによってほぼ決まる。 化石燃料から水素を製造する場合には、当然のことながら循環型エネルギーシステムとはなりえずCO2発生の問題も残る。 しかし、一方では、原料の輸送・貯蔵・供給に関わる現有のインフラが活用できるという大きなメリットもある。 メタノールを使う場合には、バイオマスなどでCO2からメタノールを再生する技術が確立すれば循環型システムを 構築することが可能だが、供給量の確保などの課題がある。水から水素を製造する場合には原子力のような他のエネルギー源が必要となり、 水素エネルギーシステムの燃料資源量や環境汚染物質排出量は1次エネルギーの供給手段のそれらによって決定されることになる。 原子力の国民的信頼性がさらに高まり、水素製造に必要な1次エネルギー源として認知されれば、エネルギー供給における原子力の重要性は 著しく増大することになる。
    一方、原子力関連の研究開発、特に核融合に関わるものは、水素エネルギー関連の開発研究と 共通の学問的・技術的基盤に立脚しているものが多い。例えば、トリチウムの貯蔵に用いる合金と水素貯蔵合金とに 求められる性質は本質的には同じであり、水素同位体の吸蔵量や放出温度などの”仕様”が異なっているに過ぎない。 また、海水やトリチウム廃液から重水素やトリチウムを回収する技術は、水から水素を製造する技術として応用できるし、 その逆もしかりである。すなわち、水素エネルギー分野は原子力分野で得られた研究成果を輸出する市場として極めて魅力的であり、 また、水素エネルギー分野での技術開発の成果を導入することにより、原子力分野を発展させることもできるわけである。
    以上のような観点から、「原子力関連材料と水素」というシリーズの中にあえて本解説を加え、 水素エネルギー社会の実現に向けて進められている研究の一端を紹介させていただくこととした。本稿が原子力と 水素エネルギーの関わりについてお考えいただくきっかけとなれば幸いである。水素エネルギーシステムは、 水素の製造・輸送・貯蔵・供給・エネルギー変換という多くの部分から構成され、関連する材料も非常に多岐にわたっているため、 限られた著者らの知識と誌面でそれを網羅することは不可能である。本稿では、水素の製造に関わる水素透過膜材料、 高容量水素貯蔵材料として、注目を集めているリチウム系水素貯蔵材料、エネルギー変換に直接関わる触媒材料に話を 限定することをお許しいただきたい。

  • 水素透過膜 — 波多野雄治
  • リチウム系水素貯蔵材料の開発 — 中森裕子, 折茂慎一
  • 燃料電池用水素電極触媒 — 井上光浩, 阿部孝之


The toroidal pump limiter ALT-II in TEXTOR

K.H. Finkena, D. Reitera, T. Dennera, K.H. Dippela, J. Hobirka, G. Manka, H. Kevera, G.H. Wolfa, N. Nodab, A. Miyaharab, T. Shojic, K.N. Satob, K. Akaishib, J.A. Boedod, J.N. Brookse, R.W. Connd, W.J. Corbettd, R.P. Doernerd, D. Goebeld, D.S. Grayd, D.L. Hillisf, J. Hoganf, R.T. McGrathg, M. Matsuyamah, R. Moyerd, R.E. Nygreng, J. Watkinsg

aInstitut fur Plasmaphysik, Forschungszentrum Julich GmbH, EURATOM Association, Trilateral Euregio Cluster, D-52425 Julich, Germany

bNational Institute for Fusion Science, Orochi-Cho, Toki, Gifu, Japan

cNagoya University, Department of Energy Engineering and Science, 464-8603 Nagoya, Japan

dUniversity of California, San Diego, Department of Applied Mechanics and Engineering Sciences San Diego, California

eArgonne National Laboratory, Argonne, Illinois

fOak Ridge National Laboratory, Building 9201-2, MS-8072, Oak Ridge, Tennessee

gSandia National Laboratories, Albuquerque, New Mexico

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


    The Advanced Limiter Test (ALT) project is the focus of a fruitful and intense International Energy Agreement collaboration on TEXTOR. The pump limiter is a mechanical boundary that is laid out for taking the full heat load of TEXTOR, namely 8 MW (assuming 2 MW radiated power) for 10 s, and provides a pumping efficiency of at least 5% of the working gas. This layout is adopted from the requirements of a fusion reactor: It is mandatory to remove both the full power that is convected to the limiter or divertor and the helium ash that is generated in the fusion process. In order to obtain pumping for all gases, the ALT-II is equipped with turbomolecular pumps. A short description of ALT-II is given, and the power and particle fluxes to the limiter surface and into the exhaust scoops are discussed. Requirements of the helium removal rate for a reactor and relevant measurements are discussed, and particle removal and the power distribution to the limiters are treated. Related topics of the ALT-II program were hydrogen recycling and the measurement of turbulence-induced anomalous particle transport in the plasma edge.



波多野雄治, 阿部孝之



    「水素」という言葉は広く浸透しつつあるが、「水素同位体」となると、なじみの薄い方も 多いのではないだろうか。一般に水素と呼ばれているのは、3種類ある同位体のなかで最も軽い「軽水素」であり、 このほかに「重水素」と「三重水素」が存在する。これら同位体のすべてが、エネルギー源として大きなポテンシャルを 秘めている。すなわち、軽水素は水に変わることにより環境汚染物質を排出せずエネルギーを生み出す燃料となり、 重水素と三重水素は、水やバイオマスから水素を生み出す核融合エネルギーの源となる。


A new kind of column materials for gas chromatographic hydrogen isotope separation

M. Hara, H. Shima, S. Akamaru, T. Abe, M. Matsuyama, K. Watanabe

Hydrogen Isotope Res. Centr., Toyama Univ., Gofuku 3190, Toyama 930-8555, Japan


    A new kind of materials that can be applied to a gas chromatographic hydrogen isotope separation system was developed to reduce the amount of Pd-Pt alloy required for making the column and to improve the separation efficiency. Pd and Pt were deposited on α-Al2O3 powder by using a barrel sputtering system. Prepared sample powder was characterized from surface morphology, element distributions on the surface, composition and crystallinity. The characterization showed that a uniform layer of Pd-Pt alloy with expected composition was formed on Al2O3 particles. The crystallinity, however, was poor, but improved after annealing at 1073 K for 2 hours. The hydrogen absorbing behavior was also improved by the annealing. A separation column was prepared from the annealed powder and was subjected to experiments on hydrogen isotope separation. The column of annealed powder gave considerably good separation efficiency around room temperature, in spite that only 0.35 g of Pd-Pt was used for the column. The amount of Pd-Pt alloy used here should be compared to previous results, where 1.5 g of Pd-Pt powder was required for high separation efficiency. The new material was quite effective to reduce the amount of Pd-Pt alloy without compromising the separation efficiency and can give further improvement.


A study on a tritium separation process using self-developing gas chromatography with Pd-Pt alloy

S. Kojimaa, M. Yokosawab, M. Matsuyamac, M. Numataa, T. Katob, K. Watanabec

aJGC Corporation, Research & Development Center: 2205 Narita-cho, Oarai-machi, Higashiibaraki-gun, Ibaraki 311-1313, Japan

bJGC Corporation, Nuclear Environment Project Division: 3-1 Minato Mirai 2-chome, Nishi-ku, Yokohama 220-6001, Japan

cHydrogen Isotope Research Center, Toyama University: Gifuku 3190, Toyama 930-8555, Japan


    To study the practical application of a tritium separation process using Self-Developing Gas Chromatography (SDGC) using a Pd-Pt alloy, intermediate scale-up experiments (22 mm ID x 2 m length colum) and the development of a computational simulation method have been conducted. In addition, intermediate scale production of Pd-Pt Powder has been developed for the scale-up experiments.
    The following results were obtained: (1) a 50-fold scale-up from 3 mm to 22 mm causes no significant impact on the SDGC process; (2) the Pd-Pt alloy powder is applicable to a large size SDGC process; and (3) the simulation enables preparation of a conceptual design of a SDGC process for tritium separation.


Chronic release of tritium from SS316 at ambient temperature: correlation between depth profile and tritium liberation

Y. Torikai, R.-D. Penzhorn, M. Matsuyama, K. Watanabe

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


    One conceivable option for the disposal of tritium-contaminated stainless steel consists in its storage at ambient temperature in a purged containment. To assess this option several stainless steel 316 specimens, previously loaded at elevated temperatures with 0.8-8.5 MBq of tritium, were flushed continuously with dry argon (water partial pressure 0.073 Pa) for extended periods of time. The released tritium (more than 99 % in the form of tritiated water (HTO)) was collected in bubblers and monitored periodically by liquid scintillation counting. After an initial fast liberation a fairly constant rate of the order of 0.2 % per day established. Tritium depth profile in the SS specimens could be simulated by a diffusion limited desorption model. The rate determining step for tritium release appears to be bulk diffusion.


In-situ measurement of high level tritiated water by bremsstrahlung counting

M. Matsuyama, Y. Torikai, K. Watanabe

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


    The applicability of bremsstrahlung counting to in-examined. A specially desighed metallic vial fitted with a gold-coated beryllium window was prepared for the present examinations. Only tritiated water of a given amount was put into the vial. The volume dependence of the X-ray intensity showed that 5 cm3 of tritiated water is sufficient for measurements. It was found that the spectrum of X-rays induced by β-rays consisted of only bremsstrahlung. The bremsstrahlung spectrum could be reproduced quite well by computational simulation. A good linear relation between the X-ray intensity and tritium concentration was obtained in the concentration range of 4x10-3 - 40 MBq cm-3. Furthermore, effect of nickel added as a model impurity to tritiated water was examined, and it was found that the tritium concentration can be evaluated from the X-ray intensity without any correction in the presence of impurity below 200 ppm.


Development of a low-level tritium air monitor

Y. Sakumaa, T. Iidab, T. Koganezawab, Y. Ogatac, T. Aoyama, Y. Torikaid, M. Ohtae, M. Takamie

aNational Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5295, Japan

bGraduate School of Engineering, Nagoya University, Furou-cho, Chikusa-ku, Nagoya 464-8603, Japan

cSchool of Health Sciences, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan

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

eFaculty of Engineering Niigata University, 8050 Ikarashi 2-no-cho, Niigata 950-2181, Japan


    There are three components which contain tritium in the air, i.e. water vapor, molecular hydrogen and methane [1][2]. However, there is no tritium monitor, which is able to measure the concentration separately. In the light of it, we are developing a new monitor, which will be enable us to measure the tritium concentrations in two of these species, i.e. molecular hydrogen and methane. The specific activities of tritium in molecular hydrogen and in methane are very high. Then if we can collect the hydrogen and the methane, we will easily measure the tritium concentrations. We have conceptually designed a new tritium monitor and carried out several basic experiments. Based on the results of these experiments, we have estimated the performance of the monitor. For an hour counting, the monitor will be able to measure the tritium concentrations of molecular hydrogen and methane using about 4m3 air. Since the total performance of the monitor mainly depends on the capability of the proportional counter, we are developing an appropriate counter.


Surface modification of polymer microparticles using a hexagonal-barrel sputtering system

Takayuki Abea, Satoshi Akamarua, Kuniaki Watanabea, Y. Hondab

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

bYoutec Company, Nishihirai 986-1, Nagareyama, Chiba 270-0156, Japan


    Surfaces of spherical polymer microparticles with three different sizes (50, 12 and 5 μm in diameter) were modified with platinum using the hexagonal barrel equipped RF sputtering system. It was found that the surfaces of particles could be uniformly coated with Pt layers, regardless of their sizes. It should be noticed that the present system made it possible to form a uniform Pt-layer over a polymer particle of 1 μm diameter. Cyclic voltammograms (CVs) of the Pt-coated samples gave the same CV as that of bulky Pt, indicating that electrochemical characteristics of the Pt-layers are identical with those of Pt metal.

Keywords: Hexagonal-barrel sputtering system; Surface modification of polymer microparticles


Tritium distribution in JET Mark IIA type divertor tiles analysed by BIXS

Y. Torikaia, M. Matsuyamaa, N. Bekrisb, M. Gluglab, P. Coadc, W. Naegeled, A. Erbed, N. Nodae, V. Philippsf, K. Watanabea

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

bEURATOM Association, Forschungszentrum Karlsruhe, Tritium Laboratory, D-76021 Karlsruhe, Germany

cEURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, OXON OX14 3DB, UK

dEURATOM Association, Forschungszentrum Karlsruhe, Institute for Material Research II, D-76021 Karlsruhe, Germany

eNational Institute for Fusion Science, Oroshi-cho, Toki-shi, Gifu 509-5292, Japan

fEURATOM Association, Forschungszentrum Julich, Institute for Plasma Physics, TEC, 52425 Julich, Germany


    Distribution of tritium concentrations on the surface and in the bulk (up to 1 mm in depth) in a complete poloidal set of divertor tiles exposed to D-T plasma shots in JET was measured by β-ray-induced X-ray spectrometry (BIXS). The observed X-ray spectra showed that tritium distribution was different not only from tile to tile but also highly non-uniform in each individual tile. The peaks of bulk tritium concentration obtained by BIXS are correlated with the corresponding one obtained previously by other methods. For the first time, tritium depth profiles in the plasma-facing surface of complete divertor tiles were obtained by BIXS and they can be classified by four types of a tritium depth profile.

Keywords: Divertor; JET; Tritium