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Haga, Katsuhiro; Kogawa, Hiroyuki; Wakui, Takashi; Harada, Masahide; Futakawa, Masatoshi; Kaminaga, Masanori; Kato, Takashi; Okamoto, Yoshihisa
PSI-Proceedings 07-01, p.55 - 65, 2008/01
The construction of the 1MW class mercury target which the world highest level as the spallation neutron source has been finished under the J-PARC project. The mercury target system consists of the mercury target vessel, the mercury circulation system and the target trolley. The outline of the mercury target system and several topics appeared in the course of the system fabrication and assembling are reported. For the target vessel, the residual stress at the beam window was evaluated and it was confirmed that the stress level is low and no problem. For the mercury pump, the mechanical EM pump which is free of mercury leak was developed and we could get prospect that the pump can be used under the beam condition of up to 400kW. For the target trolley, we confirmed that the very heavy body which is nearly 300t can be positioned with the accuracy of 
1mm which is required for the system operation.
Haga, Katsuhiro; Futakawa, Masatoshi; Kogawa, Hiroyuki; Wakui, Takashi; Naoe, Takashi; Yamazaki, Shogo*; Tanaka, Nobuatsu*
PSI-Proceedings 07-01, p.67 - 70, 2008/01
Pressure wave, which is caused by the thermal shock in mercury at the moment the high intense proton beams bombard mercury, is a crucial issue to realize a pulsed high-power mercury target for spallation neutron sources. R&D on pressure wave mitigation technologies is carried out in JSNS. Micro-bubbles injection into mercury is one of prospective technologies to mitigate the pressure waves. The CFD simulation was carried out to investigate the injected bubble distribution in our mercury target that is influenced by bubble size and bubbling location. Also, the micro-bubbles effect was experimentally investigated from the viewpoint of pitting damage in the mercury loop with MIMTM (electro-Magnetic IMpact Testing Machine) and examined numerically from the viewpoint of bubble dynamics. As results, we confirmed that the micro-bubble is very effective to reduce the pressure response and pitting damage.
Kikuchi, Kenji; Dai, Y.*
no journal, ,
Proton beam current is 20 mA in a high-power target with beam power of 30 MW and proton energy of 1.5 GeV. Liquid metals will be candidate target materials because of good heat transfer performance and irradiation damage free. Lead bismuth eutectic is thought to be a primary substance from the point of view of target performance and natural resources. In this radiation field material radiation damage is estimated to be 5 DPA (p) and 50 DPA (n) per year, including neutrons from both spallation reaction and reactor core burning processes. SINQ target irradiation program (STIP) provides useful material radiation fields up to 10 DPA due to proton and another 10DPA due to neutron. In order to describe irradiation materials damage, the particle characterization must be from points of views of its energy and a kind of particle. In addition the evaluation of He gas production, which remains in the materials after irradiation, must be done.