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Kai, Tetsuya; Uchida, Toshitsugu; Kinoshita, Hidetaka; Seki, Masakazu; Oi, Motoki; Wakui, Takashi; Haga, Katsuhiro; Kasugai, Yoshimi; Takada, Hiroshi
Journal of Physics; Conference Series, 1021(1), p.012042_1 - 012042_4, 2018/06
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Takada, Hiroshi; Naoe, Takashi; Kai, Tetsuya; Kogawa, Hiroyuki; Haga, Katsuhiro
Proceedings of 12th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '15), p.297 - 304, 2016/00
In J-PARC, we have continuously been making efforts to operate a mercury target of a pulsed spallation neutron source with rated power of 1-MW. One of technical progresses is to mitigate cavitation damages at the target vessel front induced by the 3-GeV proton beam injection at 25 Hz. We have improved the performance of a gas micro-bubbles injection into the mercury target, resulting that no significant cavitation damages was observed on the inner surface of target vessel after operation for 2050 MWh with the 300-kW proton beam. Another progress is to suppress the release of gaseous radioactive isotopes, especially tritium, during the target vessel replacement. We have introduced a procedure to evacuate the target system by an off-gas processing apparatus when it is opened during the replacement operation, achieving to suppress the tritium release through the stack. For example, the amount of released tritium was 12.5 GBq, only 5.4% of the estimated amount, after the 2050 MWh operation. After these progresses, the operating beam power for the pulsed spallation neutron source was ramped up to 500-kW in April, 2015.
Nakamura, Hiroo; Ida, Mizuho*; Matsuhiro, Kenjiro; Fischer, U.*; Hayashi, Takumi; Mori, Seiji*; Nakamura, Hirofumi; Nishitani, Takeo; Shimizu, Katsusuke*; Simakov, S.*; et al.
JAERI-Review 2005-005, 40 Pages, 2005/03
JAERI-Review-2005-005.pdf:3.52MB
The International Fusion Materials Irradiation Facility (IFMIF) is being jointly planned to provide an accelerator-based Deuterium-Lithium (Li) neutron source to produce intense high energy neutrons (2 MW/m
) up to 200 dpa and a sufficient irradiation volume (500 cm
) for testing the candidate materials and components up to about a full lifetime of their anticipated use in ITER and DEMO. To realize such a condition, 40 MeV deuteron beam with a current of 250 mA is injected into high speed liquid Li flow with a speed of 20 m/s. In target system, radioactive species such as 7Be, tritium and activated corrosion products are generated. In addition, back wall operates under severe conditions of neutron irradiation damage (about 50 dpa/y). In this paper, the thermal and thermal stress analyses, the accessibility evaluation of the IFMIF Li loop, and the tritium inventory and permeation of the IFMIF Li loop are summarized as JAERI activities on the IFMIF target system performed in FY2004.
Nakamura, Hiroo; Burgazzi, L.*; Cevolani, S.*; Dell'Ocro, G.*; Fazio, C.*; Giusti, D.*; Horiike, Hiroshi*; Ida, Mizuho*; Kakui, Hideo*; Loginov, N.*; et al.
Journal of Nuclear Materials, 307-311(Part.2), p.1675 - 1679, 2002/12
Times Cited Count：4 Percentile：28.81(Materials Science, Multidisciplinary)This paper describes the latest design of the IFMIF liquid Li target system reflecting the KEP results. Future prospects will be also summarized. To handle an averaged heat flux of 1 GW/m2 under a continuous 10 MW D beam deposition, a high-speed Li flow of 20 m/s, a double reducer nozzle and a concaved flow are applied to the target design. Hydraulic characteristics of the Li target design have been validated in a water jet experiment. To obtain a control scenario of the Li loop in an accident of the D beam trip, a transient analysis has been done. To control tritium and impurities in Li, a cold trap and two kinds of hot trap are adopted in Li purification loop. To maintain reliable continuous operation, various diagnostics are attached to the target assembly. To exchange the target assembly and back wall, a remote handling system with a multi axis arm and welding/cutting tool are designed. As an option, design of a replaceable back wall with a mechanical seal is being in progress. In a next phase of IFMIF beyond 2004, a Li test loop will be constructed for engineering validation.
Nakamura, Hiroo; Ida, Mizuho*; Sugimoto, Masayoshi; Yutani, Toshiaki*; Takeuchi, Hiroshi
Fusion Science and Technology, 41(3), p.845 - 849, 2002/05
This paper presents the design considerations on removal and control of tritium generated in liquid lithium target of International Fusion Materials Irradiation Facility (IFMIF). In the IFMIF, intense neutrons simulating fusion condition are produced by injecting deuterium beam with a maximum energy of 40 MeV and a maxim current of 250 mA into the liquid lithium flow with a speed of 20 m/s. Tritium is produced by direct reactions of the beam with the lithium. Total production rate is estimated to be about 10 g/year.As a reference method of the tritium removal, a cold trap with a swamping method is used. As an option, yttrium getter hot trap is considered. The concentration of hydrogen isotopes in the Li flow is detected by measuring their partial gas pressure which comes through a Nb or Nb-Zr membrane. To distinguish the isotopes from the other, a quadrupole mass spectrometer is used. The off-line sampling system is also used to measure the tritium concentration in the lithium.
; Nakamura, Hideo; ; Takeuchi, Hiroshi; S.Cevolani*; Martone, M.*; T.Hua*; D.Smith*; Katsuta, Hiroji
Proc. of 2nd Int. Topical Meeting on Nuclear Applications of Accelerator Technology (AccApp'98), p.541 - 547, 1998/00
no abstracts in English
; Ikeda, Yujiro; Kusano, Joichi
JAERI-M 94-016, 89 Pages, 1994/02
no abstracts in English
; ; ;
JAERI-M 86-105, 45 Pages, 1986/08
no abstracts in English
; ; ; ; ; ;
Journal of Nuclear Science and Technology, 20(8), p.686 - 697, 1983/00
Times Cited Count：5 Percentile：56.65(Nuclear Science & Technology)no abstracts in English
