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Journal Articles

Stable structure of hydrogen atoms trapped in tungsten divacancy

Osawa, Kazuhito*; Toyama, Takeshi*; Hatano, Yuji*; Yamaguchi, Masatake; Watanabe, Hideo*

Journal of Nuclear Materials, 527, p.151825_1 - 151825_7, 2019/12

 Times Cited Count:2 Percentile:42.44(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Effect of neutron energy and fluence on deuterium retention behaviour in neutron irradiated tungsten

Fujita, Hiroe*; Yuyama, Kenta*; Li, X.*; Hatano, Yuji*; Toyama, Takeshi*; Ota, Masayuki; Ochiai, Kentaro; Yoshida, Naoaki*; Chikada, Takumi*; Oya, Yasuhisa*

Physica Scripta, 2016(T167), p.014068_1 - 014068_5, 2016/02

 Times Cited Count:25 Percentile:83.87(Physics, Multidisciplinary)

The irradiation defects were introduced by Fe$$^{2+}$$ irradiation, fission neutron irradiation and D-T neutron irradiation. After the irradiation, the deuterium ions (D$$_{2}^{+}$$) implantation was performed and the D retention behavior was evaluated by thermal desorption spectroscopy. The experimental results indicated that dense vacancies and voids within the shallow region near the surface were introduced by Fe$$^{2+}$$ irradiation. The trapping state of D by vacancies and void were clearly controlled by the damage concentration and the voids would become the most stable D trapping site. For fission neutron irradiated W, most of the D was adsorbed on the surface and/or trapped by dislocation loops and no vacancies and voids for D trapping due to its lower damage concentration. D trapping by vacancies were found in the bulk of D-T neutron irradiated W, indicating that the neutron energy distribution could make a large impact on irradiation defect formation and the D retention behavior.

Journal Articles

Evaluation of selected grades of beryllium metal as reflector materials for extended lifetime performance

Dorn, C. K.*; Tsuchiya, Kunihiko; Takemoto, Noriyuki; Ito, Masayasu; Hori, Junichi*; Chekushina, L.*; Hatano, Yuji*; Chakrov, P.*; Kawamura, Hiroshi

Proceedings of 6th International Symposium on Material Testing Reactors (ISMTR-6) (Internet), 9 Pages, 2013/10

no abstracts in English

Journal Articles

Tritium distribution on the tungsten surface exposed to deuterium plasma and then to tritium gas

Isobe, Kanetsugu; Alimov, V. Kh.*; Taguchi, Akira*; Saito, Makiko; Torikai, Yuji*; Hatano, Yuji*; Yamanishi, Toshihiko

Journal of Plasma and Fusion Research SERIES, Vol.10, p.81 - 84, 2013/02

The distribution of hydrogen trapping sites on W surface exposed with D plasma was examined by the techniques of imaging plate and autoradiography. Recrystallized W specimens were exposed with D plasma at around 495 and 550 K to the same fluence of 10$$^{26}$$ D/m$$^{2}$$. Then, tritium was introduced into specimen by the exposure to tritium gaseous at 473 K. After that, the tritium distribution on W surface was examined by the techniques of imaging plate and autoradiography. From the results of the imaging plate, tritium was found to be highly concentrated within the area exposed with D plasma and the concentration of tritium was slightly varied even in that area. In the autoradiograph of W surface, it was found that tritium concentrated on the grain boundary and blisters.

Journal Articles

Basic study on surface chemical combination between beryllium metal and hydrogen isotope gas, 2

Ito, Masayasu; Kitagishi, Shigeru; Hanawa, Yoshio; Tsuchiya, Kunihiko; Hatano, Yuji*; Matsuyama, Masao*; Nagasaka, Takuya*; Hishinuma, Yoshimitsu*

Annual Report of National Institute for Fusion Science; April 2011 - March 2012, P. 535, 2012/12

Beryllium has been utilized as a moderator and/or reflector in a number of material testing reactors. Beryllium is also supposed to be widely used in fusion reactors as neutron multiplier and protective walls of plasma facing components. It is important to perform the characterization of the different grade beryllium such as the productivity, mechanical and chemical properties and the interaction under water and/or gas environment. In this study, three kinds of beryllium (S-200F, S-65H, I-220H) were prepared, and corrosion test and surface analysis of these beryllium samples were carried out for life time expansion under pure water. As a result, the surface change of each Be sample was observed by the corrosion test and influenced by the content of BeO and the grain size.

Journal Articles

Development of beryllium material for reflector lifetime expansion

Dorn, C. K.*; Tsuchiya, Kunihiko; Hatano, Yuji*; Chakrov, P.*; Kodama, Mitsuo*; Kawamura, Hiroshi

Proceedings of 5th International Symposium on Material Testing Reactors (ISMTR-5) (Internet), 9 Pages, 2012/10

The JMTR has used beryllium reflector since it began operation in 1968. Beryllium has been used as the reflector element material in the reactor, specifically S-200F structural grade beryllium in JMTR. As a part of the reactor upgrade, the Japan Atomic Energy Agency (JAEA) has carried out the cooperation experiments to extend the operating lifetime of the beryllium reflector elements. Thus, three kinds of beryllium metals such as S-200F, S-65H and I-220H were selected at the viewpoints of production methods, impurities and grain size of beryllium starting powders, mechanical properties. Now, data of the material properties and interaction between pure water and these beryllium grades are accumulated under un-irradiated. Additionally, irradiation tests have been prepared and development of PIE technologies has been performed. In this paper, the results of various properties and irradiation test plan for lifetime expansion of beryllium are described for material testing reactors.

Journal Articles

Deuterium behaviour at the interface of oxidized metal under high temperature heavy water

Nakamura, Hirofumi; Hatano, Yuji*; Yamanishi, Toshihiko

Fusion Engineering and Design, 87(5-6), p.916 - 920, 2012/08

 Times Cited Count:3 Percentile:28.72(Nuclear Science & Technology)

Deuterium behavior in the metal exposed to hot heavy water has been investigated in order to understand the oxidation driven tritium permeation in the fusion reactor. Disks of SS304, F82H and Ni and gold plated SS304 and F82H were oxidized in an autoclave at 573K. After the oxidation, soaked deuterium in the specimen was measured by the thermal desorption method and elemental depth distribution in the specimen was measured by a glow discharge optical elemental spectroscopy method. Obtained results were followings, (1) The oxide thickness has grown with the soaking time, and solved deuterium amount also increases with oxidation time for all materials. (2) Deuterium exists at the interface of the oxide and metal for all materials. (3) Deuterium in the gold plated samples were less than that in the bare SS304 about 1/5. (4) Deuterium in nickel was less than that in the SS304 by one orders magnitude and oxide thickness was also thinner than SS304. Those results indicate that deuterium solution into the material would be initiated by the deuterium gas production at the oxidation process of metal. Gold plating as the oxidation protection could be effective to prevent deuterium solution into the metal.

Journal Articles

Tritium absorption of co-deposited carbon films

Nobuta, Yuji*; Yamauchi, Yuji*; Hino, Tomoaki*; Akamaru, Satoshi*; Hatano, Yuji*; Matsuyama, Masao*; Suzuki, Satoshi; Akiba, Masato

Fusion Engineering and Design, 87(7-8), p.1070 - 1073, 2012/08

 Times Cited Count:2 Percentile:20.56(Nuclear Science & Technology)

Journal Articles

Status of material development for lifetime expansion of beryllium reflector

Dorn, C. K.*; Tsuchiya, Kunihiko; Hatano, Yuji*; Chakrov, P.*; Kodama, Mitsuo*; Kawamura, Hiroshi

JAEA-Conf 2011-003, p.93 - 97, 2012/03

The JMTR has used beryllium reflector since it began operation in 1968. Beryllium has been used as the reflector element material in the reactor, specifically S-200F structural grade beryllium in JMTR. As a part of the reactor upgrade, the Japan Atomic Energy Agency (JAEA) has carried out the cooperation experiments to extend the operating lifetime of the beryllium reflector elements. Thus, three kinds of beryllium metals such as S-200F, S-65H and I-220H were selected at the viewpoints of production methods, impurities and grain size of beryllium starting powders, mechanical properties. Now, data of the material properties of these beryllium grades are accumulated under un-irradiated and irradiated conditions. In this paper, the results of various properties and irradiation test plan for lifetime expansion of beryllium are described for material testing reactors.

Journal Articles

Transfer of tritium in concrete coated with hydrophobic paints

Fukada, Satoshi*; Edao, Yuki*; Sato, Koichi*; Takeishi, Toshiharu*; Katayama, Kazunari*; Kobayashi, Kazuhiro; Hayashi, Takumi; Yamanishi, Toshihiko; Hatano, Yuji*; Taguchi, Akira*; et al.

Fusion Engineering and Design, 87(1), p.54 - 60, 2012/01

 Times Cited Count:4 Percentile:36.4(Nuclear Science & Technology)

An experimental study on tritium (T) transfer in porous concrete for the tertiary T safety containment is performed to investigate (1) how fast HTO penetrates through concrete walls, (2) how well concrete walls contaminated with water-soluble T are decontaminated by a solution-in-water technique, and (3) how well hydrophobic paint coating works as a protecting film against HTO migrating through concrete walls. The epoxy paint coating can work as a HTO diffusion barrier and the PRF value is around 1/10. The silicon paint coating cannot work as the anti-T permeation barrier, because water deteriorates contact between the paint and cement or mortar.

Journal Articles

Basic study on surface chemical combination between beryllium metal and hydrogen isotope gas

Tsuchiya, Kunihiko; Kitagishi, Shigeru; Ito, Masayasu; Hanawa, Yoshio; Hatano, Yuji*; Matsuyama, Masao*; Nagasaka, Takuya*; Hishinuma, Yoshimitsu*

Annual Report of National Institute for Fusion Science; April 2010 - March 2011, P. 545, 2011/11

no abstracts in English

Journal Articles

Surface analysis for chemical combination of beryllium metals

Tsuchiya, Kunihiko; Hanawa, Yoshio; Kitagishi, Shigeru; Ito, Masayasu; Hatano, Yuji*; Matsuyama, Masao*

Heisei-21-Nendo Toyama Daigaku Kyodo Riyo, Kyodo Kenkyu Seika Hokokusho, p.9 - 10, 2010/12

no abstracts in English

Journal Articles

Accomplishments of the large amount of tritium handling technology, 1; Accumulation of the safety operation experiences of tritium handling facilities and the related safety studies

Hatano, Yuji*; Yamada, Masayuki; Hayashi, Takumi

Purazuma, Kaku Yugo Gakkai-Shi, 86(3), p.173 - 184, 2010/03

DT fusion reactor has been studied. In this type of fusion reactor, about 500 g of tritium should be burned and produced every day in the 100 MWe class of reactor. Fusion reactor has itself the potential safety, however, the most important safety point of the DT fusion reactor is tritium confinement. In this report, large amount of tritium safety handling experiences, accumulated in the Hydrogen Isotope Research Center, University of Toyama, and in the Tritium Process Laboratory, Japan Atomic Energy Agency, are summarized and its accomplishments of the related safety studies are also reviewed.

Journal Articles

Hydrogen production in the $$gamma$$-radiolysis of aqueous sulfuric acid solutions containing Al$$_{2}$$O$$_{3}$$, SiO$$_{2}$$, TiO$$_{2}$$ or ZrO$$_{2}$$ fine particles

Yamada, Reiji; Nagaishi, Ryuji; Hatano, Yoshihiko; Yoshida, Zenko

International Journal of Hydrogen Energy, 33(3), p.929 - 936, 2008/02

 Times Cited Count:14 Percentile:37.21(Chemistry, Physical)

Hydrogen production was studied in the $$gamma$$-radiolysis of aqueous H$$_{2}$$SO$$_{4}$$ solutions containing oxide powder of Al$$_{2}$$O$$_{3}$$, SiO$$_{2}$$, TiO$$_{2}$$ or ZrO$$_{2}$$. The observed yields of final product H$$_{2}$$ increased with relative amounts of oxide powder in the solutions and exhibited a particular H$$_{2}$$SO$$_{4}$$ concentration dependence, which was different for each oxide species and its amount. The addition of a small amount of CH$$_{3}$$OH to a H$$_{2}$$SO$$_{4}$$ aqueous solution with oxide powder was quite effective for increasing the final product yields of H$$_{2}$$. The obtained results revealed that heterogeneous systems composed of oxide powder and aqueous H$$_{2}$$SO$$_{4}$$ solution were more efficient for producing H$$_{2}$$ molecules in $$gamma$$-radiolysis than homogeneous systems without oxides.

Journal Articles

Recent results on beryllium and beryllides in Japan

Mishima, Yoshinao*; Yoshida, Naoaki*; Kawamura, Hiroshi; Ishida, Kiyohito*; Hatano, Yuji*; Shibayama, Tamaki*; Munakata, Kenzo*; Sato, Yoshiyuki*; Uchida, Munenori*; Tsuchiya, Kunihiko; et al.

Journal of Nuclear Materials, 367-370(2), p.1382 - 1386, 2007/08

 Times Cited Count:23 Percentile:83.86(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Radiation-induced catalytic reduction of chromium(VI) in aqueous solution containing TiO$$_{2}$$, Al$$_{2}$$O$$_{3}$$ or SiO$$_{2}$$ fine particles

Nagaishi, Ryuji; Yoshida, Zenko; Yamada, Reiji; Hatano, Yoshihiko

Radiation Physics and Chemistry, 75(9), p.1051 - 1054, 2006/09

 Times Cited Count:7 Percentile:48.03(Chemistry, Physical)JP, H17-065162   Licensable Patent Information Database   Patent publication (In Japanese)

Reduction of chromium(VI) in aqueous neutral or basic solution was promoted by $$gamma$$-ray irradiation in the presence of oxide particles such as TiO$$_{2}$$, Al$$_{2}$$O$$_{3}$$ or SiO$$_{2}$$. The oxide particles behaved as a catalyst, and the efficiency of the Cr(VI) reduction increased with an increase of the irradiation dose irrespective of the initial Cr(VI) concentration. The insoluble Cr(III) oxide formed through the Cr(VI) reduction also acted as the catalyst.

Journal Articles

Status of beryllium R&D in Japan

Kawamura, Hiroshi; Tsuchiya, Kunihiko; Mishima, Yoshinao*; Yoshida, Naoaki*; Munakata, Kenzo*; Ishida, Kiyohito*; Hatano, Yuji*; Shibayama, Tamaki*; Sato, Yoshiyuki*; Uchida, Munenori*; et al.

INL/EXT-06-01222, p.1 - 7, 2006/02

no abstracts in English

Oral presentation

Radiation-induced reduction process of hazardous chromium(VI) ion to non-hazardous chromium oxide with the lower oxidation state in aqueous solution - oxide system

Nagaishi, Ryuji; Yamada, Reiji; Hatano, Yoshihiko; Yoshida, Zenko

no journal, , 

Radiation-induced reduction of chromium(VI) ion in aqueous solution was investigated in the presence of small amount of insoluble oxide particle such as TiO$$_{2}$$, Al$$_{2}$$O$$_{3}$$ and SiO$$_{2}$$ by using $$^{60}$$Co $$gamma$$-ray. Solution at pH $$>$$ 1.0, simulating industrial liquid waste, became neutral or basic by adding the oxide particle: the positive shift of pH of solution was dependent on the kind and particle size of oxide. The chromium(VI) ion was successfully reduced in the radiolysis of the neutral or basic solution in the presence of oxide, while not in the absence. These indicate that amount of chromium(VI) reduced by reducing radicals of water radiolysis is almost equal to that of chromium with the lower oxidation state oxidized by the oxidizing radicals in the solution, and that adsorption of chromium to oxide and enhancement in the reduction of chromium(VI) take place in the presence of oxide. The insoluble chromium(III) oxide formed in the reduction of chromium(VI) was also responsible for the reduction. The radiation-induced reduction process of hazardous chromium(VI) with utilizing high-level radioactive wastes as radiation resources was further discussed.

Oral presentation

Hydrogen production in aqueous sulfuric acid solutions containing an oxide induced by $$gamma$$-ray irradiation

Yamada, Reiji; Nagaishi, Ryuji; Hatano, Yoshihiko; Yoshida, Zenko

no journal, , 

Hydrogen production under $$gamma$$-ray irradiation in aqueous sulfuric acid solutions that contained oxide fine particles such as alpha-Al$$_{2}$$O$$_{3}$$, TiO$$_{2}$$2, ZrO$$_{2}$$, SiO$$_{2}$$ or SiO$$_{2}$$*nH$$_{2}$$O was investigated using Co-60 $$gamma$$-rays. The dependencies of sulfuric acid concentration, oxide species, and amount of added oxide powder on hydrogen production rate were studied. The experimental results show that the rate was strongly increased with the amount of added oxide powder, and that the rate exhibited each sulfuric acid concentration dependency peculiar to each oxide powder.

Oral presentation

Promoted reduction of metal ions in aqueous solution under irradiation of ionizing radiation by addition of solid oxides

Nagaishi, Ryuji; Yamada, Reiji; Yoshida, Zenko; Hatano, Yoshihiko

no journal, , 

no abstracts in English

33 (Records 1-20 displayed on this page)