Technical note for the cavitation damage inspection for interior surface of the mercury target vessel, 2; Damage depth measurement for cavitation erosion

Naoe, Takashi; Wakui, Takashi; Kinoshita, Hidetaka; Kogawa, Hiroyuki; Teshigawara, Makoto; Haga, Katsuhiro

JAEA-Technology 2023-022, 81 Pages, 2024/01

JAEA-Technology-2023-022.pdf:9.87MB

In the liquid mercury target system for the pulsed spallation neutron source of Materials and Life Science Experimental Facility (MLF) in the Japan Proton Accelerator Research Complex (J-PARC), pressure waves that is generated by the high-energy proton beam injection simultaneously with the spallation reaction, resulting severe cavitation erosion damage on the interior surface of the mercury target vessel. Because the bubble of pressure wave-induced cavitation collapsing near the interior surface of the mercury target vessel with applying the large amplitude of localized impact on the surface. Since the wall thickness of the beam entrance portion of the target vessel is designed to be 3 mm to reduce thermal stress due to the internal heating, the erosion damage has the possibility to cause the vessel fatigue failure and mercury leakage originated from erosion pits during operation. To reduce the erosion damage by cavitation, a technique of gas microbubble injection into the mercury for pressure wave mitigation, and double-walled structure of the beam window of the target vessel has been applied. A specimen was cut from the beam window of the used mercury target vessel in order to investigate the effect of the damage mitigation technologies on the vessel, and to reflect the consideration of operation condition for the next target. We have observed cavitation damage on interior surface of the used mercury target vessel by cutting out the disk shape specimens. Damage morphology and depth of damaged surface were evaluated and correlation between the damage depth and operational condition was examined. The result showed that the erosion damage by cavitation is extremely reduced by injecting gas microbubbles and the damage not formed inside narrow channel of the double-walled structure for relatively high-power operated target vessels.

Numerical visualization of herted liquid film flow behavior around a spacer in a narrow channel

Kume, Etsuo; Kitamura, Tatsuaki*; Takase, Kazuyuki; Ose, Yasuo*

Kashika Joho Gakkai-Shi, 25(Suppl.2), p.369 - 370, 2005/10

no abstracts in English

Predicted thermal-hydraulic characteristics of liquid film flow on a ribbed surface

Takase, Kazuyuki; Yoshida, Hiroyuki; Ose, Yasuo*

Proceedings of 1st International Forum on Heat Transfer (IFHT 2004), p.207 - 208, 2004/11

no abstracts in English

Liquid film flow behavior in narrow channels with roughness affected by turbulent effect

Takase, Kazuyuki; Yoshida, Hiroyuki; Ose, Yasuo*

Nihon Kikai Gakkai 2003-Nendo Nenji Taikai Koen Rombunshu, Vol.6, p.205 - 206, 2003/00

no abstracts in English

Critical heat flux correlation for subcooled boiling flow in narrow channels

Kureta, Masatoshi; Akimoto, Hajime

International Journal of Heat and Mass Transfer, 45(20), p.4107 - 4115, 2002/09

https://doi.org/10.1016/S0017-9310(02)00129-1

no abstracts in English

Study on critical heat flux in narrow rectangular channel with repeated-rib roughness, 1; Experimental facility and preliminary experiments

Kinoshita, Hidetaka; Terada, Atsuhiko*; Kaminaga, Masanori; Hino, Ryutaro

JAERI-Tech 2001-061, 43 Pages, 2001/10

JAERI-Tech-2001-061.pdf:5.21MB

no abstracts in English

Experimental study on heat transfer augmentation for high heat flux removal in rib-roughened narrow channels

M.S.Islam*; Hino, Ryutaro; Haga, Katsuhiro; Monde, Masanori*; Sudo, Yukio

JAERI-Tech 97-032, 49 Pages, 1997/07

JAERI-Tech-97-032.pdf:1.53MB

no abstracts in English

Experimental evaluation of effect flowing condition on cavitation bubble growing and collapsing behaviors

Kawamura, Shunsuke; Naoe, Takashi; Ikeda, Tsubasa; Tanaka, Nobuatsu*; Futakawa, Masatoshi

no journal, , 

A target vessel enclosing mercury made of stainless steel is used for the J-PARC spallation neutron source. It is severely damaged by the pressure-wave-induced cavitation with injecting intense proton beam. The front end of the target vessel has a double-walled structure with a narrow channel was adopted to the vessel for expecting to reduce cavitation damage. Effect of cavitation damage mitigation in narrow channel has been experimentally demonstrated. However, damage mitigation mechanism is not clarified yet. As a first step of studies to understand the mechanism of cavitation damage mitigation in narrow channel, growth and collapse behaviors of the spark-induced cavitation bubbles under flow condition were observed by using a high-speed video camera. Furthermore, the wall vibration by cavitation bubble collapse was measured by parametrically changing the flow velocity. The experimental results showed that the ejection angle of the microjet ejected by bubble collapsing leaned towards flowing direction as the flow velocity increases. The wall vibration was reduced with increasing flow velocity.