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Journal Articles

Radiochemical research for the advancement of $$^{99}$$Mo/$$^{rm 99m}$$Tc generator by (n,$$gamma$$) method

Fujita, Yoshitaka; Seki, Misaki; Namekawa, Yoji*; Nishikata, Kaori; Kimura, Akihiro; Shibata, Akira; Sayato, Natsuki; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.

KURNS Progress Report 2018, P. 155, 2019/08

no abstracts in English

Journal Articles

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

 Times Cited Count:4 Percentile:25.43(Physics, Multidisciplinary)

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for $$^{107}$$Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Journal Articles

High-temperature interaction between zirconium and UO$$_2$$

Shirasu, Noriko; Suzuki, Akihiro*; Nagae, Yuji; Kurata, Masaki

Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR 2019) (Internet), 4 Pages, 2019/05

High temperature interaction tests between UO$$_{2}$$ and Zr were performed at around 2173 K, to make clear the UO$$_{2}$$/ $$alpha$$-Zr(O) interaction and the mechanism of degradation, for developing the improved models for advanced severe accident analysis codes. A Zr plate was inserted in a UO$$_{2}$$ crucible, and heat treated at 2173 K in stream of Ar. After the heat-treatment, the samples were subjected to surface microanalysis. The middle region of Zr sample shows streak-like structures which are extended towered the top. It is confirmed that the streak-like structures were mainly consist of U from the EDX results, and the structures revealed that the U-rich phase was liquid during the heat-treatment. It seems that the U-rich liquid grew selectively toward the area where the oxygen concentration was low.

JAEA Reports

Study on the evaluation method to determine the radioactivity concentration in radioactive waste generated from post-irradiation examination facilities, 2

Tsuji, Tomoyuki; Hoshino, Yuzuru; Sakai, Akihiro; Sakamoto, Yoshiaki; Suzuki, Yasuo*; Machida, Hiroshi*

JAEA-Technology 2017-010, 75 Pages, 2017/06

JAEA-Technology-2017-010.pdf:2.31MB

It is necessary for reasonable disposal to be studied on evaluation methods to determine radioactivity concentrations in the radioactive wastes, which is generated from post-irradiation examination (PIE) facilities, for establishment of reasonable confirmation methods concerning radioactive wastes generated from research, industrial, and medical facilities. It has been chosen the PIE facilities of NUCLEAR DEVELOPMENT CORPORATION as a model for this study. As a result, it has been confirmed that the theoretical methods are applied for the important nuclides (H-3, C-14, Co-60, Ni-63, Sr-90, Tc-99, Cs-137, Eu-154, U-234, U-235, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Am-241 and Cm-244).

Journal Articles

Nitrogen hot trap design and manufactures for lithium test loop in IFMIF/EVEDA project

Wakai, Eiichi; Watanabe, Kazuyoshi*; Ito, Yuzuru*; Suzuki, Akihiro*; Terai, Takayuki*; Yagi, Juro*; Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; et al.

Plasma and Fusion Research (Internet), 11, p.2405112_1 - 2405112_4, 2016/11

BB2015-1982.pdf:2.03MB

Journal Articles

Report on special sessions in the 49th Annual Meeting of the Japan Health Physics Society

Sakoda, Akihiro; Kataoka, Noriaki*; Ishikawa, Junya*; Ota, Akio*; Suzuki, Tatsuhiko*; Nishiyama, Yuichi*; Hirouchi, Jun; Hokama, Tomonori

Hoken Butsuri, 51(3), p.181 - 186, 2016/09

The 49th annual meeting of the Japan Health Physics Society was held in Hirosaki, Aomori between June 30th and July 1st, 2016. This article gives the report on all of twelve special sessions in this meeting.

Journal Articles

Neutron irradiation effect of high-density MoO$$_{3}$$ pellets for Mo-99 production, 3

Ishida, Takuya; Suzuki, Yoshitaka; Nishikata, Kaori; Yonekawa, Minoru; Kato, Yoshiaki; Shibata, Akira; Kimura, Akihiro; Matsui, Yoshinori; Tsuchiya, Kunihiko; Sano, Tadafumi*; et al.

KURRI Progress Report 2015, P. 64, 2016/08

no abstracts in English

JAEA Reports

Decommissioning activities and R&D of nuclear facilities in the second midterm plan

Terunuma, Akihiro; Mimura, Ryuji; Nagashima, Hisao; Aoyagi, Yoshitaka; Hirokawa, Katsunori*; Uta, Masato; Ishimori, Yuu; Kuwabara, Jun; Okamoto, Hisato; Kimura, Yasuhisa; et al.

JAEA-Review 2016-008, 98 Pages, 2016/07

JAEA-Review-2016-008.pdf:11.73MB

Japan Atomic Energy Agency formulated the plan to achieve the medium-term target in the period of April 2010 to March 2015(hereinafter referred to as "the second medium-term plan"). JAEA determined the plan for the business operations of each year (hereinafter referred to as "the year plan"). This report is that the Sector of Decommissioning and Radioactive Waste Management has summarized the results of the decommissioning technology development and decommissioning of nuclear facilities which were carried out in the second medium-term plan.

Journal Articles

Technical estimation for mass production of highly-concentrated $$^{rm 99m}$$Tc solution from $$^{99}$$Mo to be obtained by ($$n,gamma$$) reaction; A Preliminary study using inactive Re instead of $$^{rm 99m}$$Tc

Tanase, Masakazu*; Fujisaki, Saburo*; Ota, Akio*; Shiina, Takayuki*; Yamabayashi, Hisamichi*; Takeuchi, Nobuhiro*; Tsuchiya, Kunihiko; Kimura, Akihiro; Suzuki, Yoshitaka; Ishida, Takuya; et al.

Radioisotopes, 65(5), p.237 - 245, 2016/05

no abstracts in English

Journal Articles

Growth of single-phase nanostructured Er$$_2$$O$$_3$$ thin films on Si (100) by ion beam sputter deposition

Mao, W.*; Fujita, Masaya*; Chikada, Takumi*; Yamaguchi, Kenji; Suzuki, Akihiro*; Terai, Takayuki*; Matsuzaki, Hiroyuki*

Surface & Coatings Technology, 283, p.241 - 246, 2015/12

 Times Cited Count:2 Percentile:86.98(Materials Science, Coatings & Films)

Single-phase nanocrystalline thin films of Er$$_2$$O$$_3$$ (440) has been first prepared using Si (100) substrates by ion beam sputter deposition at 973 K at a pressure of $$<$$ 10$$^{-5}$$ Pa and $${it in}$$-$${it situ}$$ annealing at 1023 K at a pressure of $$approx$$ 10$$^{-7}$$ Pa. Er silicides formed during the deposition are eliminated via the annealing, which results in the single phase and the smooth surface of the Er$$_2$$O$$_3$$ thin films. The epitaxial relationship between Si (100) and Er$$_2$$O$$_3$$ (110) is clarified by X-ray diffraction and reflection high energy electron diffraction.

Journal Articles

Ion-track grafting of vinylbenzyl chloride into poly(ethylene-$$co$$-tetrafluoroethylene) films using different media

Nuryanthi, N.*; Yamaki, Tetsuya; Kitamura, Akane; Koshikawa, Hiroshi; Yoshimura, Kimio; Sawada, Shinichi; Hasegawa, Shin; Asano, Masaharu; Maekawa, Yasunari; Suzuki, Akihiro*; et al.

Transactions of the Materials Research Society of Japan, 40(4), p.359 - 362, 2015/12

The ion-track grafting of a vinylbenzyl chloride (VBC) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film is necessary for preparing nanostructured hydroxide-ion-conductive electrolyte membranes. A key for success here is to obtain as high graft levels as possible (for higher conductivity) in a smaller number of tracks (for improving the other membrane properties). To this end, therefore, the effect of the medium for the VBC grafting was investigated as part of our continuing effort to optimize the experimental conditions. A 25 $$mu$$m-thick ETFE film was irradiated in a vacuum chamber with 560 MeV $$^{129}$$Xe at different fluences, and then the grafting was performed by immersing the irradiated films in a 20vol% VBC monomer at 60$$^{circ}$$C. A medium was a mixture of water (H$$_{2}$$O) and isopropyl alcohol (iPrOH) at different volume ratios. The degree of grafting increased as the H$$_{2}$$O content became higher, and reached a maximum in pure H$$_{2}$$O. These results can be explained by considering the well-known Trommsdorff effect, in which poor solubility of the grafted polymer in polar media leads to an increased polymerization rate probably due to a lower termination rate.

Journal Articles

X-ray absorption spectroscopy in the heavy Fermion compound $$alpha$$-YbAlB$$_4$$ at high magnetic fields

Terashima, Taku*; Matsuda, Yasuhiro*; Kuga, Kentaro*; Suzuki, Shintaro*; Matsumoto, Yosuke*; Nakatsuji, Satoru*; Kondo, Akihiro*; Kindo, Koichi*; Kawamura, Naomi*; Mizumaki, Masaichiro*; et al.

Journal of the Physical Society of Japan, 84(11), p.114715_1 - 114715_4, 2015/11

 Times Cited Count:1 Percentile:85.31(Physics, Multidisciplinary)

Journal Articles

SiC coating as hydrogen permeation reduction and oxidation resistance for nuclear fuel cladding

Usui, Takahiro*; Sawada, Akihiko; Amaya, Masaki; Suzuki, Akihiro*; Chikada, Takumi*; Terai, Takayuki*

Journal of Nuclear Science and Technology, 52(10), p.1318 - 1322, 2015/10

 Times Cited Count:16 Percentile:9.64(Nuclear Science & Technology)

SiC coating is one of countermeasures for the prevention of oxidation and hydrogen embrittlement of fuel claddings because SiC has high resistance of oxidation and hydrogen permeation. Hydrogen permeation and oxidation experiments for the cladding materials with SiC coatings were conducted in unirradiated conditions. The sputtering method was employed to make SiC coatings. In the hydrogen permeation experiment, SUS316 was used as a base material of the coating. SUS316 with SiC coatings showed hydrogen permeation reduction by one order of magnitude. In the oxidation experiments, Zry-4 and SUS316 were used as base materials of the coatings. The weight gain of the Zry-4 specimens with a SiC coating decreased by about one-fifth compared to the uncoated ones. This phenomenon was observed for SUS316 at 750 $$^{circ}$$C as well. The peel-off of the coating was observed in some experiments, and it is considered that the peel-off was caused by the difference of the thermal expansions between coatings and base materials. Thicker coatings showed better oxidation resistance, but thinner coatings showed more tolerance of peel-off.

Journal Articles

Synchrotron X-ray spectroscopy study on the valence state and magnetization in $$alpha$$-YbAl$$_{1-x}$$Fe$$_x$$B$$_4$$ ($$x=0.115$$) at low temperatures and high magnetic fields

Terashima, Taku*; Matsuda, Yasuhiro*; Kuga, Kentaro*; Suzuki, Shintaro*; Matsumoto, Yosuke*; Nakatsuji, Satoru*; Kondo, Akihiro*; Kindo, Koichi*; Kawamura, Naomi*; Mizumaki, Masaichiro*; et al.

Journal of Physics; Conference Series, 592(1), p.012020_1 - 012020_6, 2015/03

 Times Cited Count:1 Percentile:50.19

Valence fluctuation phenomena in rare-earth intermetallic compounds have attracted attention because the quantum criticality of the valence transition has been proposed theoretically. Recently, it was found that $$beta$$-YbAlB$$_4$$ shows quantum criticality without tuning and has a strong mixed-valence state. In this study, we measured the magnetization curve and X-ray magnetoabsorption in $$alpha$$-YbAl$$_{1-x}$$Fe$$_x$$B$$_4$$ ($$x=0.115$$), which is a locally isostructural polymorph of $$beta$$-YbAlB$$_4$$. The magnetization and X-ray experiments were performed in fields up to 55 and 40 T, respectively. A small increase in the Yb valence was observed at fields where the magnetization curve exhibited a change in slope.

Journal Articles

Status of development of Lithium Target Facility in IFMIF/EVEDA project

Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Hirakawa, Yasushi; Furukawa, Tomohiro; Hoashi, Eiji*; Fukada, Satoshi*; Suzuki, Akihiro*; Yagi, Juro*; Tsuji, Yoshiyuki*; et al.

Proceedings of Plasma Conference 2014 (PLASMA 2014) (CD-ROM), 2 Pages, 2014/11

In the IFMIF/EVEDA (International Fusion Materials Irradiation Facility/ Engineering Validation and Engineering Design Activity), the validation tests of the EVEDA lithium test loop with the world's highest flow rate of 3000 L/min was succeeded in generating a 100 mm-wide and 25 mm-thick free-surface lithium flow steadily under the IFMIF operation condition of a high-speed of 15 m/s at 250$$^{circ}$$C in a vacuum of 10 $$^{-3}$$ Pa. Some excellent results of the recent engineering validations including lithium purification, lithium safety, and remote handling technique were obtained, and the engineering design of lithium facility was also evaluated. These results will advance greatly the development of an accelerator-based neutron source to simulate the fusion reactor materials irradiation environment as an important key technology for the development of fusion reactor materials.

Journal Articles

Effects of irradiation induced Cu clustering on vickers hardness and electrical resistivity of Fe-Cu model alloys

Tobita, Toru; Nakagawa, Sho*; Takeuchi, Tomoaki; Suzuki, Masahide; Ishikawa, Norito; Chimi, Yasuhiro; Saito, Yuichi; Soneda, Naoki*; Nishida, Kenji*; Ishino, Shiori*; et al.

Journal of Nuclear Materials, 452(1-3), p.241 - 247, 2014/09

 Times Cited Count:12 Percentile:21.02(Materials Science, Multidisciplinary)

Three kinds of Fe-based model alloys, Fe-0.018 atomic percent (at.%) Cu, Fe-0.53at.%Cu, and Fe-1.06at.%Cu were irradiated with 2 MeV electrons up to the dose of 2$$times$$10$$^{-5}$$ dpa at 250$$^{circ}$$C. After the irradiation, the increase in Vickers hardness and the decrease in electrical resistivity were observed. The increase in hardness by electron irradiation is proportional to the product of the Cu contents and the square root of the electron dose. The decrease in electrical resistivity is proportional to the product of the square of Cu contents and the electron dose. Cu clustering in the materials with electron irradiation and thermal aging was observed by means of the three dimensional atom probes (3D-AP). The change in Vickers hardness and electrical resistivity is well correlated with the volume fraction of Cu clusters.

Journal Articles

Comparative study on annual $$^{137}$$Cs discharge rates after the Fukushima Dai-ichi Nuclear Power Plant accident from two distinct watershed simulation models

Kitamura, Akihiro; Imaizumi, Yoshitaka*; Yamaguchi, Masaaki; Yui, Mikazu; Suzuki, Noriyuki*; Hayashi, Seiji*

Kankyo Hoshano Josen Gakkai-Shi, 2(3), p.185 - 192, 2014/09

Annual discharge rates of radioactive cesium through selected rivers due to the Fukushima Dai-ichi Nuclear Power Plant accident were simulated by two different watershed models. One is the Soil and Cesium Transport, SACT, model which was developed by Japan Atomic Energy Agency and the other one is the Grid-Catchment Integrated Modeling System, G-CIEMS, which was developed by National Institute of Environmental Studies. We choose the Abukuma, the Ukedo, and the Niida rivers for the present study. Comparative results showed that while components and assumptions adopted in two models differ, both methods predicted the same order of magnitude estimates.

Journal Articles

Engineering validation and engineering design of lithium target facility in IFMIF/EVEDA project

Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; Watanabe, Kazuyoshi; Ida, Mizuho*; Ito, Yuzuru; Niitsuma, Shigeto; Edao, Yuki; et al.

Fusion Science and Technology, 66(1), p.46 - 56, 2014/07

 Times Cited Count:4 Percentile:59.64(Nuclear Science & Technology)

Journal Articles

Adsorption of H atoms on cubic Er$$_2$$O$$_3$$ (001) surface; A DFT study

Mao, W.*; Chikada, Takumi*; Shimura, Kenichiro*; Suzuki, Akihiro*; Yamaguchi, Kenji; Terai, Takayuki*

Journal of Nuclear Materials, 443(1-3), p.555 - 561, 2013/11

 Times Cited Count:3 Percentile:68.05(Materials Science, Multidisciplinary)

In this work, ${it ab initio}$ calculations based on density functional theory (DFT) and generalized gradient approximation were performed to investigate the structural and electronic properties of the cubic Er$$_{2}$$O$$_{3}$$ (001) surface and H adsorption processes on this surface. Several stable adsorption sites were identified, and at the most energetically favorable adsorption sites it was found that H bonds with O atoms at the cubic Er$$_{2}$$O$$_{3}$$ (001) surface with an adsorption energy of 295.68 kJ mol$$^{-1}$$ at coverage 1/8 ML, which was inclined to decrease with the increase of H coverage ($$>$$ 1/4 ML). In addition, the calculations revealed that the dissociative H atom configurations have adsorption energies that are at least 152.64 kJ mol$$^{-1}$$ greater than the H$$_2$$ molecule configurations on the surface. These results are discussed in regard of the hydrogen isotope permeation behavior in the tritium permeation barrier in a fusion reactor.

Journal Articles

Preparation of tungsten carbide nanoparticles by ion implantation and electrochemical etching

Kato, Sho; Yamaki, Tetsuya; Yamamoto, Shunya; Hakoda, Teruyuki; Kawaguchi, Kazuhiro; Kobayashi, Tomohiro*; Suzuki, Akihiro*; Terai, Takayuki*

Nuclear Instruments and Methods in Physics Research B, 314, p.149 - 152, 2013/11

 Times Cited Count:0 Percentile:100(Instruments & Instrumentation)

We implanted 100 keV W$$^+$$ in unpolished GC substrates at nominal fluences up to $$1.7times10^{17}$$ ions/cm$$^2$$. The implanted samples were electrochemically anodized in a NaOH aqueous solution to etch the surface layer. The analyses were performed by X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry (RBS), and transmission electron microscopy (TEM). XPS W 4f spectra indicated the formation of carbides as reported previously. The electrochemical etching clearly increased the W concentration on the surface. According to the RBS results, half of the implanted W atoms were retained in the substrate, while the rest should escape to the etching solution. The cross-sectional TEM image revealed a uniform distribution of WC particles with a diameter of less than 10 nm just near the surface region.

199 (Records 1-20 displayed on this page)