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Hayashi, Takao; Ochiai, Kentaro; Masaki, Kei; Goto, Yoshitaka*; Kutsukake, Chuzo; Arai, Takashi; Nishitani, Takeo; Miya, Naoyuki
Journal of Nuclear Materials, 349(1-2), p.6 - 16, 2006/02
Times Cited Count：10 Percentile：54.86(Materials Science, Multidisciplinary)Deuterium concentrations and depth profiles in plasma-facing graphite tiles used in the divertor of JT-60U were investigated by NRA. The highest deuterium concentration of D/
C of 0.053 was found in the outer dome wing tile, where the deuterium accumulated probably through the deuterium-carbon co-deposition. In the outer and inner divertor target tiles, the D/C data were lower than 0.006. Additionally, the maximum (H+D)/C in the dome top tile was estimated to be 0.023 from the results of NRA and SIMS. OFMC simulation showed energetic deuterons caused by NBI were implanted into the dome region with high heat flux. Furthermore, the surface temperature and conditions such as deposition and erosion significantly influenced the accumulation process of deuterium. The deuterium depth profile, SEM observation and OFMC simulation indicated the deuterium was considered to accumulate through three processes: the deuterium-carbon co-deposition, the implantation of energetic deuterons and the deuterium diffusion into the bulk.
Kubo, Hirotaka; JT-60 Team
Plasma Science and Technology, 8(1), p.50 - 54, 2006/01
Times Cited Count：2 Percentile：6.52(Physics, Fluids & Plasmas)no abstracts in English
Sakaba, Nariaki; Tachibana, Yukio; Nakagawa, Shigeaki; Hamamoto, Shimpei
Transactions of 18th International Conference on Structural Mechanics in Reactor Technology (SMiRT-18), p.4499 - 4511, 2005/08
Safety demonstration tests using the HTTR are now underway in order to verify the inherent safety features and to improve the safety design and evaluation technologies for HTGRs, as well as to contribute to research and development for the VHTR, which is one of the Generation IV reactor candidates. The coolant flow reduction test by running down gas circulators, which is one of the safety demonstration tests, is a simulation test of anticipated transients without scram. During the coolant flow reduction test, temperature of the high-temperature helium components and chemistry in the primary circuit are changed rapidly. This paper describes the structural integrity assessments of helium components, e.g. helium pipes, heat exchangers, during the coolant flow reduction test. From the result of this evaluation, it was found that the helium components were kept their structural integrity during temperature and chemistry transient condition in the coolant flow reduction test from the reactor power at 30%. It was also confirmed by this assessment that the coolant flow reduction test will be able to perform with its enough safety margins from the reactor power at 100%.
Sakaba, Nariaki; Nakagawa, Shigeaki; Furusawa, Takayuki*; Emori, Koichi; Tachibana, Yukio
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(4), p.388 - 395, 2004/12
Chemistry control is important for the helium coolant of High Temperature Gas-cooled Reactors (HTGRs) because impurities cause oxidation of the graphite used in the core and corrosion of high temperature materials used in the heat exchanger. In the High Temperature Engineering Test Reactor (HTTR) which is the first HTGR in Japan, the chemical impurity concentration is restricted and its behaviour is monitored during reactor operations. The impurity is reduced by the helium purification system and the concentration is measured by the helium sampling system installed to the primary and secondary helium system, continuously. This paper describes the impurity behaviour during the rise-to-power test which is the initial power-up of the HTTR. Also, the amount of the emitted impurity to the primary circuit from the graphite component and insulator used at the concentric hot gas duct are evaluated. During the power up, any abnormal impurity increases were not obtained and the chemical composition of the primary circuit is sufficiently in the stability area to avoid carbon deposition.
Zhu, X. D.; Naramoto, Hiroshi; Xu, Y.; Narumi, Kazumasa; Miyashita, Kiyoshi*
Physical Review B, 66(16), p.165426_1 - 165426_5, 2002/10
Times Cited Count：14 Percentile：56.28(Materials Science, Multidisciplinary)no abstracts in English
Naramoto, Hiroshi; Xu, Y.; Narumi, Kazumasa; Vacik, J.; Zhu, X.; Yamamoto, Shunya; Miyashita, Kiyoshi*
Materials Research Society Symposium Proceedings, Vol.647, p.O5.18.1 - O5.18.16, 2001/00
no abstracts in English
Ando, Toshiro; Takatsu, Hideyuki; Nakamura, Hiroo; Yamamoto, Masahiro; ; Arai, Takashi; Kaminaga, Atsushi; ; Horiike, Hiroshi; Shimizu, Masatsugu; et al.
Kaku Yugo Kenkyu, 65(SPECIAL ISSUE), p.27 - 49, 1991/03
no abstracts in English
Ogawa, Toru; Fukuda, Kosaku
Surface Modification Technologies,III, p.309 - 320, 1990/00
no abstracts in English
Minato, Kazuo; ;
JAERI-M 87-024, 18 Pages, 1987/02
no abstracts in English
;
Nuclear Instruments and Methods, 197, p.267 - 272, 1982/00
no abstracts in English
Ikawa, Katsuichi; Iwamoto, K.
Yogyo Kyokia-Shi, 81(938), p.403 - 406, 1973/10
no abstracts in English
