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Hayashi, Takao; Sakurai, Shinji; Sakasai, Akira; Shibanuma, Kiyoshi; Kono, Wataru*; Onawa, Toshio*; Matsukage, Takeshi*
Fusion Engineering and Design, 101, p.180 - 185, 2015/12
Times Cited Count：4 Percentile：33.25(Nuclear Science & Technology)Remote pipe welding tool accessing from inside pipe has been newly developed for JT-60SA. Remote handling (RH) system is necessary for the maintenance and repair of in-vessel components such as lower divertor cassettes in JT-60SA. Cooling pipes, which connects between the divertor cassette and the vacuum vessel with bellows are required to be cut and welded in the vacuum vessel by RH system. The available space for RH system is very limited inside the vacuum vessel, especially around the divertor cassettes. Thus, the cooling pipes are required to be cut and weld from the inside in the vacuum vessel. The inner diameter, thickness and material of the cooling pipe are 54.2 mm, 2.8 mm and SUS316L, respectively. An upper pipe connected to the divertor cassette has a jut on the edge to fill the gap between pipes. Owing to the jut and two-times welding, the welding tool achieved the maximum allowable gap of 0.7 mm.
Shibama, Yusuke; Masaki, Kei; Sakurai, Shinji; Shibanuma, Kiyoshi; Sakasai, Akira; Onawa, Toshio*; Araki, Takao*; Asano, Shiro*
Fusion Engineering and Design, 88(9-10), p.1916 - 1919, 2013/10
Times Cited Count：2 Percentile：18.63(Nuclear Science & Technology)This presentation focuses on the welding technology R&D between the JT-60SA vacuum vessel and the ports. The vacuum vessel is designed to allow port bore penetration to access the vessel inside for plasma diagnostics, and so on. There are various types of 73 ports and these are categorized by their locations; the upper/lower vertical, the upper/lower oblique, and the horizontal. Ports are onsite-welded onto the VV port stub after the assembly of the VV. This assembly sequence involves the out-vessel components such as VV thermal shield and toroidal field magnets, so that these ports welding are accessed from the inside of the vessel and limited by the internal port wall. The one of the most difficult ports are the upper vertical port with corner radius of 50 mm under narrow space, and it is necessary to clarify mobility of the weld torch head. The port weldability is discussed with the mock-up trial, which consists of the partial test pieces of the product size. The TIG welding manipulator, optimized for this R&D, is prepared by its operational simulation and examined not to interfere with the internal port wall.
Mayorshin, A. A.*; Skiba, O. V.*; Bychkov, A. V.*; Kisly, V. A.*; Shishalov, O. V.*; Krukov, F. N.*; Novoselov, A. E.*; Markov, D. V.*; Green, P. I.*; Funada, Toshio; et al.
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR 2009) (CD-ROM), 11 Pages, 2012/00
The paper presents progress results, including fabrication of vibropac MOX fuel pins and 21 FAs for fast reactor BN-600, irradiation parameters and PIE results. It is shown, that no violations of safe operation limits take place. The activities within the framework of the Demonstration experiment is based on the international cooperation and have been performed with the support and participation Russian and Japanese organizations RIAR, IPPE, OKBM, BNPP, MEXT, JAEA, PESCO. The goal of the experiment is to validate possibility of using vibropac MOX FA for weapon plutonium disposition.
Asano, Shiro*; Okuyama, Toshihisa*; Onawa, Toshio*; Yanagi, Yutaka*; Ejiri, Mitsuru*; Kanahara, Toshio*; Ichihashi, Koji*; Kikuchi, Atsushi*; Mizumaki, Shoichi*; Masaki, Kei; et al.
Fusion Engineering and Design, 86(9-11), p.1816 - 1820, 2011/10
Times Cited Count：12 Percentile：66.82(Nuclear Science & Technology)The real vacuum vessel (VV) manufacturing of JT-60SA has started since Nov. 2009 at Toshiba. Prior to starting manufacturing, fundamental welding R&Ds had been performed by three stages. In the first stage, primary tests for screening welding method were performed. In the second stage, the trial welding for 1m-long straight and curved double shell samples were conducted. The dependences of welding quality and distortion on the welding conditions, such as arc voltage and current, setting accuracy, welding sequence, the shape of grooves, etc. were measured. In addition, welding condition with low heat input was explored. In the last stage, fabrication sequence was confirmed and established by the trial manufacturing of the 20
upper half mock-up. This poster presents the R&D results obtained in the first and second stages.
Au with synchrotron radiationSowa, Makoto*; Yamazaki, Daichi*; Okada, Michio*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Toshio*
Electrical Engineering in Japan, 175(4), p.43 - 47, 2011/06
Times Cited Count：2 Percentile：18.52(Engineering, Electrical & Electronic)Yamazaki, Daichi*; Sowa, Makoto*; Okada, Michio*; Teraoka, Yuden; Kasai, Toshio*
Journal of the Vacuum Society of Japan, 54(5), p.307 - 312, 2011/05
Okada, Michio*; Sowa, Makoto*; Kasai, Toshio*; Teraoka, Yuden
Applied Surface Science, 257(9), p.4257 - 4263, 2011/02
Times Cited Count：11 Percentile：44.66(Chemistry, Physical)Hashinokuchi, Michihiro*; Sumimoto, Yuichi*; Tode, Mayumi; Harries, J.; Okada, Michio*; Teraoka, Yuden; Kasai, Toshio*
Denki Gakkai Rombunshi, C, 130(10), p.1723 - 1729, 2010/10
The oxidation processes on a TiAl surface induced by a hyperthermal O
molecular beam (HOMB) with a translational energy of 2.2 eV was studied by X-ray photoemission spectroscopy in conjunction with synchrotron radiation. At a surface temperature of 300 K, the simultaneous growth of Al and Ti oxides accompanied with the segregation of AlO near the surface was observed. The efficiency of oxidation for the HOMB incidence was smaller than that for O backfilling (25 meV). Furthermore, the chemical compositions of oxide species (AlO, TiO, TiO) on the TiAl surface were independent of the translational energy of incident O molecule. The present results suggest that the oxidation on TiAl surface proceeds via precursor molecular states.
molecular beamsOkada, Michio*; Moritani, Kosuke*; Vattuone, L.*; Savio, L.*; Teraoka, Yuden; Kasai, Toshio*; Rocca, M.*
Metal Oxide Nanostructures and Their Applications, 1, p.205 - 237, 2010/03
The use of hyperthermal O molecular beams may improve the quality of thin film growth, for example, for organic films, and allow the production of oxide layers at lower crystal temperatures, avoiding contamination problems and reducing film defects. Collision-induced absorption and local heating of the substrate were shown to be indeed effective in inducing oxide nucleation, opening up new possibilities for the production of nanostructured metal oxides. Herein we offer an overview on recent detailed studies of oxygen adsorption and of the initial stages of CuO and CuO formation on low Miller index and vicinal Cu surfaces. We introduce the hyperthermal molecular beam technique and give some details on the experimental apparatuses. We discuss the available data for Cu(100), Cu(410) and Cu(110) and Cu(111), respectively.
Moritani, Kosuke*; Okada, Michio*; Teraoka, Yuden; Yoshigoe, Akitaka; Kasai, Toshio*
Journal of Physical Chemistry A, 113(52), p.15217 - 15222, 2009/10
Times Cited Count：11 Percentile：35.59(Chemistry, Physical)Oxygen adsorption and subsequent oxide formation on Cu(110) using a hyperthermal oxygen molecular beam (HOMB) has been investigated using SR-XPS. The O-uptake curves, which were determined from the evolution of O-1s peaks, indicate that simple Langmuir type kinetics can describe dissociative adsorption of O with an incident energy (Ei) below 0.5eV under oxygen coverage of 0.5 ML. The reaction order dependence on Ei implies two competing dissociation mechanisms, trapping-mediated and directly-activated adsorption. Oxidation at oxygen coverage larger than 0.5 ML proceeds rather effectively using highly energetic HOMB at Ei larger than 1.0 eV. The surface CuO formed with highly-energetic HOMB incidence decomposes with desorbing subsurface oxygen even at room temperature. This indicates that HOMB can induce a meta stable surface structure that cannot be produced in the thermal equilibrium process.
Au with synchrotron radiationSowa, Makoto*; Yamazaki, Daichi*; Okada, Michio*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Toshio*
Denki Gakkai Rombunshi, C, 129(2), p.229 - 232, 2009/02
Native oxide at CuAu(110) surface has been studied by high energy-resolution X-ray photoemission spectroscopy with synchrotron radiation. The clean surface of CuAu(110) is terminated by Au and Cu atoms with equal contents. After oxidation in the air, Cu atoms segregated on the surface and the Cu-oxide was formed. In other words, Au atoms moved into the bulk. Au atoms below the oxide prevented the O atom diffusion into the bulk. Surface index dependences of natural oxidation suggested in every cases that the diffusion of Cu atoms contributed to the oxide formation.
Moritani, Kosuke*; Okada, Michio*; Teraoka, Yuden; Yoshigoe, Akitaka; Kasai, Toshio*
Journal of Physical Chemistry C, 112(23), p.8662 - 8667, 2008/06
Times Cited Count：32 Percentile：67.47(Chemistry, Physical)This paper reports a study on the reconstruction at Cu(111) surface induced by a hyperthermal oxygen molecular beam (HOMB) at room temperature. The HOMB incidence at translational energies larger than 0.5 eV induced surface reconstruction in the oxygen coverage larger than 0.27 ML. On the other hand, long-range-ordered structures were not formed even at the oxygen coverage of 0.4 ML for the backfilling of thermal O at room temperature. The O1s XPS peak for the HOMB incidence at room temperature was resolved into two components, 529.4 and 528.9 eV, at the oxygen coverage larger than 0.27 ML, which can be assigned to the O atoms occupying the threefold hollow sites on the unreconstructed Cu(111) surface and four-coordinated sites on the reconstructed structure, respectively. Annealing the reconstructed surface at 620 K decreased the oxygen coverage to 0.27 ML and induced so-called "29" superstructure.
Hashinokuchi, Michihiro*; Okada, Michio*; Ito, Hironori*; Kasai, Toshio*; Moritani, Kosuke*; Teraoka, Yuden
Physical Review Letters, 100(25), p.256104_1 - 256104_4, 2008/06
Times Cited Count：16 Percentile：65.76(Physics, Multidisciplinary)We report results of studies on surface-temperature dependence of steric effects in dissociative adsorption processes of NO molecules on Si(111)-(7
7) surface by means of X-ray photoemission spectroscopy. Data presented here show that the reactive sticking probability for N-end collisions is larger than that in O-end collisions at an incident energy of 58 meV. Furthermore, this steric preference is quite sensitive to the surface temperature and the surface coverage. These facts reveal that transient surface trapping of NO molecules in a shallow precursor state plays a key role in the initial step of the NO decomposition on the Si(111)-(77) surface.
Okada, Michio*; Hashinokuchi, Michihiro*; Moritani, Kosuke*; Kasai, Toshio*; Teraoka, Yuden
Japanese Journal of Applied Physics, 47(5), p.3686 - 3691, 2008/05
Times Cited Count：5 Percentile：22.74(Physics, Applied)An oriented-molecular-beam technique based on the Stark effect of a molecule in an inhomogeneous hexapole electrostatic field is a potential tool for stereochemical control of surface reactions. This technique allows us to select a specific rotational quantum state and also an orientation of a reagent molecule. We have developed a new UHV-compatible oriented-molecular-beam machine. This apparatus is equipped with components for X-ray photoemission spectroscopy (XPS) in order to detect surface-reaction products. In the dissociative adsorption of NO on an Si(111) surface, we found a steric effect in the reactivity by monitoring the products on the surface with the new machine. The N-end collision is more reactive than the O-end collision at an incident energy of 58 meV. To our knowledge, this is the first measurement of the steric effect appearing in the reaction products on the surface.
7) surfaceHashinokuchi, Michihiro*; Ito, Hironori*; Teraoka, Yuden; Moritani, Kosuke*; Okada, Michio*; Kasai, Toshio*
Japanese Journal of Applied Physics, 47(3), p.1672 - 1676, 2008/03
Times Cited Count：4 Percentile：18.78(Physics, Applied)Dissociative adsorption of nitric oxide (NO) on Si(111)-77 surface between 330-600 K was investigated using X-ray photoelectron spectroscopy. The uptake curves of both N and O atoms as a function of NO dose revealed a prominent temperature dependence of dissociative adsorption of NO on an Si(111)-77 surface. The decrease in the rates of dissociative adsorption of NO with increasing surface temperature suggested existence of a precursor state. Additionally, the N/O ratio on the surface changed from 1.0 at 330 K to 1.2 at 600 K. This increasing N/O ratio with increasing surface temperature suggests that an additional reaction path opens at higher surface temperature.
O formation via hyperthermal O adsorption at Cu(410)Okada, Michio*; Vattuone, L.*; Gerbi, A.*; Savio, L.*; Rocca, M.*; Moritani, Kosuke*; Teraoka, Yuden; Kasai, Toshio*
Journal of Physical Chemistry C, 111(46), p.17340 - 17345, 2007/11
Times Cited Count：18 Percentile：50.99(Chemistry, Physical)We report a study on the oxidation process of Cu(410) using high-resolution electron energy loss spectroscopy and X-ray photoemission spectroscopy using synchrotron radiation. We demonstrate that a hyperthermal O molecular beam (HOMB) is an efficient tool to fabricate CuO thin film also at room temperature. The efficiency of the CuO formation in the initial stages depends on the angle of incidence of HOMB. Step roughening, acting as a source of mobile precursor Cu adatoms and opening channels for bulk diffusion of the O atoms, is a key feature in determining the CuO formation rate.
Okada, Michio*; Vattuone, L.*; Moritani, Kosuke*; Savio, L.*; Teraoka, Yuden; Kasai, Toshio*; Rocca, M.*
Journal of Physics; Condensed Matter, 19(30), p.305022_1 - 305022_7, 2007/08
Times Cited Count：8 Percentile：38.69(Physics, Condensed Matter)We studied the oxidation of Cu(410) for thermal O exposure and using High-resolution Electron Energy-loss Spectroscopy. CuO is identified by loss peaks at 19 meV and 79 meV. By monitoring the intensity of the latter, we find that CuO formation depends strongly on surface temperature and on O pressure and is kinetically limited by the impinging O flux. Thermally activated step roughening, leading to detachment of Cu adatoms from the step edge, acts as a source of mobile Cu atoms allowing for subsequent nucleation of CuO patches.
on Cu surfacesMoritani, Kosuke*; Tsuda, Muneyuki*; Teraoka, Yuden; Okada, Michio*; Yoshigoe, Akitaka; Fukuyama, Tetsuya*; Kasai, Toshio*; Kasai, Hideaki*
Journal of Physical Chemistry C, 111(27), p.9961 - 9967, 2007/07
Times Cited Count：15 Percentile：45.93(Chemistry, Physical)We report an X-ray photoemission study of the dissociative adsorption of O at Cu(111), (001), and (110) surfaces with an O molecular beam generated with a variable temperature nozzle. The O-uptake curves, which are produced from precisely measured O-1s peaks, indicate that the dissociative absorption is enhanced as the nozzle temperature is increased up to 1000 K for the normal incidence of O at a kinetic energy of 0.5 eV. However, further increasing the nozzle temperature to 1400 K reduces the probability of dissociativeadsorption. These results suggest that vibrational excitations of incident O assist dissociative adsorption while rotational excitations hinder it.
molecular beamOkada, Michio*; Vattuone, L.*; Moritani, Kosuke*; Savio, L.*; Teraoka, Yuden; Kasai, Toshio*; Rocca, M.*
Physical Review B, 75(23), p.233413_1 - 233413_4, 2007/06
Times Cited Count：34 Percentile：76.82(Materials Science, Multidisciplinary)We studied the oxidation of Cu(410) using X-ray photoemission spectroscopy performed with synchrotron radiation. We demonstrate that a hyperthermal O molecular beam is an efficient tool to fabricate Cu oxide thin films at room temperature (RT) and even lower temperatures. At RT, mainly CuO forms. At around 100 K, CuO nucleation also takes place; this is noteworthy, since this moiety is usually produced only at much higher 
and ambient pressure.
Au(100) using hyperthermal O molecular beamOkada, Michio*; Hashinokuchi, Michihiro*; Fukuoka, Masayuki*; Kasai, Toshio*; Moritani, Kosuke*; Teraoka, Yuden
Applied Physics Letters, 89(20), p.201912_1 - 201912_3, 2006/11
Times Cited Count：25 Percentile：64.91(Physics, Applied)Oxidation of CuAu(100) using a hyperthermal O molecular beam (HOMB) was investigated by X-ray photoemission spectroscopy in conjunction with a synchrotron light source. From the incident energy dependence of the O-uptake curve, it was determined that the dissociative adsorption of O implies a higher activation barrier and therefore less reactivity due to the Au alloying. The dissociative adsorption progresses with the Cu segregation on the surface. No prominent growth of CuO even for 2 eV HOMB suggests that the Au-alloying of Cu can serve as a protective layer against further oxidation into the bulk.
