Development of microbubble generator for suppression of pressure waves in mercury target of spallation source

Kogawa, Hiroyuki; Naoe, Tomoki; Kyotoh, Harumichi; Haga, Katsuhiro; Kinoshita, Hidetaka; Futakawa, Masatoshi

doi:10.1080/00223131.2015.1009188

Cited by 27 publications

(16 citation statements)

References 9 publications

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“…8 that the dynamic response (10 kHz low-pass filtered signal) from 0 to 1.5 ms dramatically decreased with the injection of gas microbubbles. It was reported that the peak displacement velocity of the target vessel was well correlated with the proton beam conditions, including beam power and beam profile (peak energy deposition in mercury) [14].…”

Section: Effect Of Injecting Gas Microbubbles On Cavitation Damagementioning

confidence: 99%

“…Fig. 8 shows the time histories of the displacement velocities of the JSNS mercury target vessel obtained using a laser Doppler vibrometer (LDV) system [14,26]. Detailed descriptions of the measurement are not given here, and it can be seen in Fig.…”

Section: Effect Of Injecting Gas Microbubbles On Cavitation Damagementioning

confidence: 99%

“…The numerically calculated saturation time of negative pressure at the center of the beam window portion, t n , is expressed in terms of beam power and peak energy deposition as follows [14]:…”

Section: Effect Of Negative Pressure Period On Damagementioning

confidence: 99%

“…The target vessel has a triplewalled structure comprising a mercury vessel and a double-walled water-cooled shroud, a so-called safety-hull, to prevent mercury spill-out. The vessel has a reflective mirror attached to the outer surface that reflects laser beams to evalu-ate pressure waves using a laser Doppler vibrometer, which was installed at the JSNS [14].…”

Section: Introductionmentioning

confidence: 99%

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Cavitation damage prediction for the JSNS mercury target vessel

Naoe

Kogawa

Wakui

et al. 2016

Journal of Nuclear Materials

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The liquid mercury target system for the Japan Spallation Neutron Source (JSNS) at the Materials and Life science experimental Facility (MLF) in the Japan Proton Accelerator Research Complex (J-PARC) is designed to produce pulsed neutrons. The mercury target vessel in this system, which is made of type 316L stainless steel, is damaged by pressure wave-induced cavitation due to proton beam bombardment. Currently, cavitation damage is considered to be the dominant factor influencing the service life of the target vessel rather than radiation damage. In this study, cavitation damage to the interior surface of the target vessel was predicted on the basis of accumulated damage data from off-beam and on-beam experiments. The predicted damage was compared with the damage observed in a used target vessel. Furthermore, the effect of injecting gas microbubbles on cavitation damage was predicted through the measurement of the acoustic vibration of the target vessel. It was shown that the predicted depth of cavitation damage is reasonably coincident with the observed results. Moreover, it was confirmed that the injection of gas microbubbles had an effect on cavitation damage.

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Section: Effect Of Injecting Gas Microbubbles On Cavitation Damagementioning

confidence: 99%

Section: Effect Of Injecting Gas Microbubbles On Cavitation Damagementioning

confidence: 99%

Section: Effect Of Negative Pressure Period On Damagementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cavitation damage prediction for the JSNS mercury target vessel

Naoe

Kogawa

Wakui

et al. 2016

Journal of Nuclear Materials

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“…We developed a gas microbubble generator [17] for generating bubbles to satisfy the design condition mentioned above, and have installed it in the mercury target system with a closed-loop gas supply system in October 2012. Figure 3b,d show the photograph and schematic of the microbubble generator.…”

Section: Microbubble Injection Systemmentioning

confidence: 99%

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex I: Pulsed Spallation Neutron Source

Tazaki

Haga

Teshigawara

et al. 2017

QuBS

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Abstract:At the Japan Proton Accelerator Research Complex (J-PARC), a pulsed spallation neutron source provides neutrons with high intensity and narrow pulse width pulse to promote researches on a variety of science in the Materials and Life Science Experimental Facility (MLF). It was designed to be driven by a proton beam with an energy of 3 GeV, a power of 1 MW at a repetition rate of 25 Hz, that is world's highest power level. It is still on the way towards the goal to accomplish the operation with a 1 MW proton beam. In this review, distinctive features of the target-moderator-reflector system of the pulsed spallation neutron source are presented.

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