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Naoe, Takashi; Kogawa, Hiroyuki; Wakui, Takashi; Haga, Katsuhiro; Teshigawara, Makoto; Kinoshita, Hidetaka; Takada, Hiroshi; Futakawa, Masatoshi
Journal of Nuclear Materials, 468, p.313 - 320, 2016/01
Times Cited Count：11 Percentile：71.23(Materials Science, Multidisciplinary)Mercury target vessel in the JSNS, which is made of 316L SS, is damaged owing to the pressure wave-induced cavitation resulting from the proton beam bombardment. The cavitation damage decreases the structural integrity of the target vessel and is currently a dominant factor to decide the service life in compared with the radiation damage. Injecting microbubbles into mercury is one of the prospective techniques to mitigate the pressure waves and cavitation damage. In the JSNS, a microbubble generator with a gas circulation system was installed and has been operated since October 2012. The effects of microbubble injection into mercury on pressure wave mitigation were studied using a laser Doppler vibrometer. The result showed that the vibrational velocity of the target vessel is clearly reduced according to the increase of void fraction. An average peak vibrational velocity under 340 kW operation with the void fraction of 0.1% was reduced to 1/4 of that without injecting microbubbles.
Naoe, Takashi; Xiong, Z.; Futakawa, Masatoshi
Journal of Nuclear Materials, 468, p.331 - 338, 2016/01
Times Cited Count：18 Percentile：85.45(Materials Science, Multidisciplinary)Mercury enclosure vessel of the JSNS made of an austenitic stainless steel suffers radiation damage in the proton and neutron environment. In addition to the radiation damage, the vessel suffers the cyclic impact loading caused from the pressure waves. The JSNS target vessel suffers higher than 2
10
cyclic loading. Furthermore, strain rate of the beam window portion of the target vessel reaches to 50s
at the maximum, which is much higher than the conventional fatigues. Very high cycle fatigue strengths up to 10
cycles for solution annealed (SA) and 10% cold-worked 316L (CW) were investigated through the ultrasonic fatigue test. The result showed that the fatigue strengths of SA and CW tested in high-strain rate were higher than that of the conventional fatigue. On the other hand, the fatigue failure occurred regardless of material and temperature in the very high-cycle region (
cycles) at the stress amplitude of below the conventional fatigue limit.
Maekawa, Fujio; Sasa, Toshinobu; Takei, Hayanori; Saito, Shigeru; Obayashi, Hironari; Yamaguchi, Kazushi; Wan, T.; Tsujimoto, Kazufumi; Nishihara, Kenji; Sugawara, Takanori; et al.
no journal, ,
As one of experimental facilities of J-PARC (Japan Proton Accelerator Research Complex), we have a plan to construct the Transmutation Experimental Facility (TEF). TEF consists of two facilities: the ADS Target Test Facility (TEF-T) and the Transmutation Physics Experimental Facility (TEF-P). TEF-T equips a liquid lead-bismuth spallation target bombarded by a 400 MeV - 250 kW proton beam in which candidate proton beam window materials are to be irradiated. TEF-P equips a critical/subcritical assembly to investigate physical and dynamic properties of the accelerator-driven system by using a low power (10W) proton beam. Uranium, Plutonium and minor actinide fuels are planned to be loaded into the assembly. Recent progress in R&D efforts toward construction of J-PARC TEF will be presented.
