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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：5 Percentile：38.15(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.
Furukawa, Tomohiro; Hirakawa, Yasushi; Kondo, Hiroo; Kanemura, Takuji; Wakai, Eiichi
Fusion Engineering and Design, 98-99, p.2138 - 2141, 2015/10
Times Cited Count：13 Percentile：65.51(Nuclear Science & Technology)In the International Fusion Materials Irradiation Facility (IFMIF), a back plate of the target assembly will be exchanged during the in-service period. During the works, the lithium components will react chemically with the surrounding atmosphere. In this research, the chemical reaction of lithium in air, oxygen and nitrogen containing variable humidity at room temperature has been investigated to estimate the chemical reaction during the exchange works.
Saigusa, Mikio*; Oyama, Gaku*; Matsubara, Fumiaki*; Takii, Keita*; Sai, Takuma*; Kobayashi, Takayuki; Moriyama, Shinichi
Fusion Engineering and Design, 96-97, p.577 - 582, 2015/10
Times Cited Count：6 Percentile：43.95(Nuclear Science & Technology)A wideband polarizer has been developed for an ECCD system in JT-60SA. The groove depth of the mirrors installed in miter bends were optimized for two frequencies (110 GHz and 138 GHz) by numerical simulations. All surfaces of Poincare spheres were covered at both of the frequencies in low power test. The thermal stress of polarizer were estimated by the numerical simulations. The twister polarizer has been tested up to 0.24 MW during 3 s at 110 GHz.
Tsuru, Daigo; Sakurai, Shinji; Nakamura, Shigetoshi; Ozaki, Hidetsugu; Seki, Yohji; Yokoyama, Kenji; Suzuki, Satoshi
Fusion Engineering and Design, 98-99, p.1403 - 1406, 2015/10
Times Cited Count：4 Percentile：31.62(Nuclear Science & Technology)Isobe, Kanetsugu; Kawamura, Yoshinori; Iwai, Yasunori; Oyaizu, Makoto; Nakamura, Hirofumi; Suzuki, Takumi; Yamada, Masayuki; Edao, Yuki; Kurata, Rie; Hayashi, Takumi; et al.
Fusion Engineering and Design, 98-99, p.1792 - 1795, 2015/10
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Activities on Broader Approach (BA) were started in 2007 on the basis of the Agreement between the Government of Japan and the EURATOM. The period of BA activities consist of Phase1 and Phase2 dividing into Phase 2-1 (2010-2011), Phase 2-2 (2012-2013) and Phase 2-3 (2014-2016). Tritium technology was chosen as one of important R&D issues to develop DEMO plant. R&D activities of tritium technology on BA consist of four tasks. Task-1 is to prepare and maintain the tritium handling facility in Rokkasho BA site in Japan. Task 2, 3 and 4 are main R&D activities for tritium and these are focused on: Task-2) Development of tritium accountancy technology, Task-3) Development of basic tritium safety research, Task-4) Tritium durability test. R&D activities of tritium technology in Phase 2-2 were underway successfully and closed in 2013.
Shibama, Yusuke; Okano, Fuminori; Yagyu, Junichi; Kaminaga, Atsushi; Miyo, Yasuhiko; Hayakawa, Atsuro*; Sagawa, Keiich*; Mochida, Tsutomu*; Morimoto, Tamotsu*; Hamada, Takashi*; et al.
Fusion Engineering and Design, 98-99, p.1614 - 1619, 2015/10
Times Cited Count：4 Percentile：31.62(Nuclear Science & Technology)The JT-60SA vacuum vessel (150 tons) is a double wall torus structure and the maximum major radius of 5.0 m and height of 6.6 m. The manufacturing design concept is that the vessel is split in the 10 toroidal sectors manufactured at factory, and assembled on-site; seven of the 40-degree sectors, two of the 30-degree beside final one, and the final of the 20-degree. The final sector is assembled with the VV thermal shield and toroidal field magnets into the 340-degree as prepared in one sector. Sectors are temporally fitted on-site and adjusted one over the other before the assembly. After measurement of the dimensions and the reference, these sectors are transferred onto the cryostat base. First, three 80-degree sectors are manufactured with mating each 40-degree sector by direct joint welding. The rest sectors including the final sector are jointed with splice plates. Welding manipulator and its guide rails are used for these welding. In this paper, the detail of the VV sectors assembly including the final sector is explained. Welding technologies to joint the two of 40-degree sectors are reported with the present manufacturing status and the welding trial on the vertical stub with the partial mock-up of the final sector are discussed with the assembly process.
Nakamichi, Masaru; Kim, Jae-Hwan
Fusion Engineering and Design, 98-99, p.1838 - 1842, 2015/10
Times Cited Count：16 Percentile：77.59(Nuclear Science & Technology)Advanced neutron multipliers with high stability at high temperatures are desired for the pebble bed blankets of DEMO reactors. Beryllium intermetallic compounds (beryllides) are the most promising material for this purpose. To fabricate the beryllide pebbles, a new granulation process has been established that combines a plasma sintering method for beryllide synthesis and a rotating electrode method using a plasma-sintered electrode for granulation. In granulation examinations, prototypic pebbles 1 mm in diameter of Be-V beryllide as well as Be-Ti beryllide were successfully fabricated. This study performed not only granulation of binary beryllides but also its characterization of the hydrogen generation reaction with water vapor compared with those of pure Be pebbles.
Ozawa, Kazumi; Tanigawa, Hiroyasu; Morisada, Yoshiaki*; Fujii, Hidetoshi*
Fusion Engineering and Design, 98-99, p.2054 - 2057, 2015/10
Times Cited Count：1 Percentile：9.26(Nuclear Science & Technology)Reduced activation ferritic/martensitic steel, as typified by F82H, is a promising candidate for structural material of DEMO fusion reactors. To prevent plasma sputtering, tungsten (W) coating was essentially required. This study aims to examine the irradiation effects on hardness and microstructure of vacuum-plasma-spray coated W-F82H steel, with a special emphasis on the impacts of grain-refining induced by frictional stir processing (FSP). It was revealed that the hardness of the VPS-FSP W after ion-irradiation to 5.4 dpa at 800
C were not remarkably changed, where bulk W usually exhibited significant irradiation hardening.
Ota, Masayuki; Sato, Satoshi; Ochiai, Kentaro; Konno, Chikara
Fusion Engineering and Design, 98-99, p.1847 - 1850, 2015/10
Times Cited Count：2 Percentile：16.69(Nuclear Science & Technology)International Reactor Dosimetry and Fusion File release 1.0 (IRDFF 1.0), has been released from the International Atomic Energy Agency (IAEA) recently. In order to validate and test IRDFF 1.0, IAEA has initiated a new Co-ordinated Research Project (CRP). Under this CRP, we have performed an integral experiment on a graphite pseudo-cylindrical slab assembly with DT neutron source at JAEA/FNS. The graphite assembly of 31.4 cm in equivalent radius and 61 cm in thickness is placed at a distance of about 20 cm from the DT neutron source. A lot of foils for the dosimetry reactions in IRDFF1.0 are inserted into the small spaces between the graphite blocks along the center axis of the assembly. After DT neutron irradiation, reaction rates for the dosimetry reactions are measured by the foil activation technique. This experiment is analyzed by using Monte Carlo neutron transport code MCNP5-1.40 with recent nuclear data libraries of ENDF/B-VII.1, JEFF-3.2, and JENDL-4.0. The experimental assembly and DT neutron source are modeled precisely in the MCNP calculation. The reaction rates calculated with IRDFF 1.0 as the response functions for the dosimetry reactions are compared with the experimental values. Also the calculations with JENDL Dosimetry File 99 (JENDL/D-99) are performed for comparison. The results calculated with IRDFF 1.0 show good agreement with the experimental results.
Matsunaga, Go; Takechi, Manabu; Sakurai, Shinji; Suzuki, Yasuhiro*; Ide, Shunsuke; Urano, Hajime
Fusion Engineering and Design, 98-99, p.1113 - 1117, 2015/10
Times Cited Count：18 Percentile：79.42(Nuclear Science & Technology)Kanemura, Takuji; Kondo, Hiroo; Furukawa, Tomohiro; Hirakawa, Yasushi; Hoashi, Eiji*; Yoshihashi, Sachiko*; Horiike, Hiroshi*; Wakai, Eiichi
Fusion Engineering and Design, 98-99, p.1991 - 1997, 2015/10
Times Cited Count：16 Percentile：77.59(Nuclear Science & Technology)A high-speed (15 m/s) liquid lithium jet is planned to be utilized as the target of two 40 MeV - 125 mA deuteron beams in the International Fusion Materials Irradiation Facility (IFMIF). The target thickness is required to be maintained within 25 
1 mm under a vacuum condition of 10
Pa. This paper reports the result of measurements of the Li-target thickness under the IFMIF condition (Li speed of 10 to 20 m/s, vacuum pressure of 10 Pa, Li temperature of 250C) in the EVEDA Li Test Loop. The target thickness was found to be 26.08 mm on average at the speed of 15 m/s at the center of the IFMIF beam footprint. As for temporal fluctuation, average and maximum amplitude at the same measurement position were 0.26 and 1.45 mm, respectively, and more than 99.7% of all amplitudes measured were within the design requirement. Therefore, it was found that the Li target fulfilled the required stability for IFMIF.
Sukegawa, Atsuhiko; Murakami, Haruyuki; Matsunaga, Go; Sakurai, Shinji; Takechi, Manabu; Yoshida, Kiyoshi; Ikeda, Yoshitaka
Fusion Engineering and Design, 98-99, p.2076 - 2079, 2015/10
Times Cited Count：2 Percentile：16.69(Nuclear Science & Technology)The JT-60SA project is a EU - JA satellite tokamak under Broader Approach in support of the ITER project. In-vessel coils are designed and assembled by JA. The resin-insulator is required to have a heat resistance against the baking temperature of vacuum vessel of 
200C (40000 hour). Thus the assessment of the heat load is fundamental for the design of the coils. However, the estimation of the lifetime of resin-insulator under the high-temperature region has not been examined. In the present study, the estimation of the lifetime of seven candidate resin-insulators such as epoxy resin and cyanate-ester resin under the 220C temperature region have been performed for the current coils design. Weight reduction of the seven candidate insulators was measured at different heating times under 180C, 200C and 220C environment using three thermostatic ovens, respectively. The reduction of the insulators has been used as input for Weibull-analysis towards Arrhenius-plot. Lifetime of the resins has been estimated for the first time at the high temperature region by the plot. Lifetime of the resin-insulators have been evaluated and discussed as well as the available temperature of the in-vessel coils.
Kim, Jae-Hwan; Nakamichi, Masaru
Fusion Engineering and Design, 98-99, p.1812 - 1816, 2015/10
Times Cited Count：7 Percentile：49.28(Nuclear Science & Technology)Wakai, Eiichi; Kikuchi, Takayuki; Kim, B.*; Kimura, Akihiko*; Nogami, Shuhei*; Hasegawa, Akira*; Nishimura, Arata*; Soldaini, M.*; Yamamoto, Michiyoshi*; Knaster, J.*
Fusion Engineering and Design, 98-99, p.2089 - 2093, 2015/10
Times Cited Count：17 Percentile：79.42(Nuclear Science & Technology)Ferro, A.*; Gaio, E.*; Novello, L.*; Matsukawa, Makoto; Shimada, Katsuhiro; Kawamata, Yoichi; Takechi, Manabu
Fusion Engineering and Design, 98-99, p.1053 - 1057, 2015/10
Times Cited Count：3 Percentile：24.66(Nuclear Science & Technology)Lampasi, A.*; Zito, P.*; Coletti, A.*; Novello, L.*; Matsukawa, Makoto; Shimada, Katsuhiro; Burini, F.*; Kuate-Fone, Y.*; Taddia, G.*; Tenconi, S.*
Fusion Engineering and Design, 98-99, p.1098 - 1102, 2015/10
Times Cited Count：11 Percentile：65.51(Nuclear Science & Technology)Zito, P.*; Lampasi, A.*; Coletti, A.*; Novello, L.*; Matsukawa, Makoto; Shimada, Katsuhiro; Cinarelli, D.*; Portesine, M.*; Dorronsoro, A.*; Vian, D.*
Fusion Engineering and Design, 98-99, p.1191 - 1196, 2015/10
Times Cited Count：13 Percentile：71.17(Nuclear Science & Technology)Ezato, Koichiro; Suzuki, Satoshi; Seki, Yohji; Mori, Kensuke; Yokoyama, Kenji; Escourbiac, F.*; Hirai, Takeshi*; Kuznetsov, V.*
Fusion Engineering and Design, 98-99, p.1281 - 1284, 2015/10
Times Cited Count：43 Percentile：96.17(Nuclear Science & Technology)Japan Atomic Energy Agency (JAEA) is now devoting to development of Full-W ITER divertor outer vertical target (OVT), especially, PFU that needs to withstand the repetitive heat load as high as 20MW/m
. JAEA have succeeded in demonstrating that the soundness of a bonding technology is sufficient for the full-W ITER divertor. For the development of bonding technology, the load carrying capability test on the W monoblock with a leg attachment to an OVT support structure was carried out and shows that the attachment can withstand against the uniaxial load more than 20 kN which is three times higher than the IO requirement. JAEA manufactured 6 small-scale mock-ups and tested under the repetitive heat load of 10 and 20 MW/m to examine the durability of the divertor structure including W tile bonding and the cooling tube. All of the mock-ups could survived 5000 cycles at 10 MW/m and 1000 cycles 20 MW/m with no failure such as debonding of the W tile and water leak from the cooling tube. The number of cycles at 20 MW/m is three times longer than the requirement of ITER divertor.
Uto, Hiroyasu; Tobita, Kenji; Someya, Yoji; Asakura, Nobuyuki; Sakamoto, Yoshiteru; Hoshino, Kazuo; Nakamura, Makoto
Fusion Engineering and Design, 98-99, p.1648 - 1651, 2015/10
Times Cited Count：7 Percentile：49.28(Nuclear Science & Technology)Maintenance schemes are one of the critical issues in DEMO design, significantly affecting the configuration of in-vessel components, the size of toroidal field coil, the arrangement of poloidal field coils, reactor building, hot cell and so forth. Therefore, the maintenance schemes should satisfy many design requirements and criteria to assure reliable and safe plant operation and to attain reasonable plant availability. In this study, we categorize various schemes in term of (1) the maintenance port position for transporting blanket segments, (2) blanket segmentation, and (3) divertor segmentation. In reviewing these assessment factors, the separated sector transport using the vertical maintenance ports with small divertor cassette maintenance scheme was found to be a more probable maintenance approach. This presentation describes engineering design of each maintenance schemes and evaluation results of comparison among maintenance schemes.
Maistrello, A.*; Gaio, E.*; Novello, L.*; Matsukawa, Makoto; Yamauchi, Kunihito
Fusion Engineering and Design, 98-99, p.1109 - 1112, 2015/10
Times Cited Count：9 Percentile：58.41(Nuclear Science & Technology)
