Chapter 10
Heat Transfer Study for ADS Solid Target:
Surface Wettability and Its Effect
on a Boiling Heat Transfer
Daisuke Ito, Kazuki Hase, and Yasushi Saito
Abstract In relationship to a solid target cooling system of an accelerator-driven
system (ADS), wettability effect on boiling heat transfer has been experimentally
investigated by irradiation with ultraviolet and gamma rays (γ-rays). The experimental apparatus consists of a copper heater block, a rectangular container, and a
thermostat bath. Two copper heater blocks were fabricated: one is for radiationinduced surface activation (RISA) and the other is for photoelectric reaction by
ultraviolet whose heat transfer surface is coated by a TiO 2 film. These copper heater
blocks were irradiated by ultraviolet or by γ-rays to change the surface wettability.
Boiling heat transfer under subcooling conditions was measured before and after
the irradiations to study the wettability effect. Experimental results show that
nucleate boiling curves are shifted to the higher wall superheated side with the
irradiated surface because of the decrease of the active nucleation sites. Heat
transfer enhancement was found in both the critical heat flux and microbubble
emission boiling (MEB) regions under these experimental conditions.
Keywords Microbubble emission boiling • Photocatalysis • Proton beam
• Radiation-induced surface activation • Surface wettability
10.1 Introduction
An accelerator-driven system (ADS) is a hybrid-type nuclear system consisting of a
proton accelerator, a spallation target, and a subcritical assembly in which highenergy particles and high heat density are generated in the target and subcritical
assembly by the spallation and fission reactions. Lead-bismuth is considered the
leading candidate for the liquid-metal spallation target for nuclear transmutation
D. Ito (*) • Y. Saito
Research Reactor Institute, Kyoto University, 2-1010 Asashiro-nishi,
Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
e-mail: itod@rri.kyoto-u.ac.jp
K. Hase
Power Systems Company, Toshiba Corporation, Kawasaki, Japan
© The Author(s) 2015
K. Nakajima (ed.), Nuclear Back-end and Transmutation Technology for Waste
Disposal, DOI 10.1007/978-4-431-55111-9_10
95
Heat Transfer Study for ADS Solid Target:
Surface Wettability and Its Effect
on a Boiling Heat Transfer
Daisuke Ito, Kazuki Hase, and Yasushi Saito
Abstract In relationship to a solid target cooling system of an accelerator-driven
system (ADS), wettability effect on boiling heat transfer has been experimentally
investigated by irradiation with ultraviolet and gamma rays (γ-rays). The experimental apparatus consists of a copper heater block, a rectangular container, and a
thermostat bath. Two copper heater blocks were fabricated: one is for radiationinduced surface activation (RISA) and the other is for photoelectric reaction by
ultraviolet whose heat transfer surface is coated by a TiO 2 film. These copper heater
blocks were irradiated by ultraviolet or by γ-rays to change the surface wettability.
Boiling heat transfer under subcooling conditions was measured before and after
the irradiations to study the wettability effect. Experimental results show that
nucleate boiling curves are shifted to the higher wall superheated side with the
irradiated surface because of the decrease of the active nucleation sites. Heat
transfer enhancement was found in both the critical heat flux and microbubble
emission boiling (MEB) regions under these experimental conditions.
Keywords Microbubble emission boiling • Photocatalysis • Proton beam
• Radiation-induced surface activation • Surface wettability
10.1 Introduction
An accelerator-driven system (ADS) is a hybrid-type nuclear system consisting of a
proton accelerator, a spallation target, and a subcritical assembly in which highenergy particles and high heat density are generated in the target and subcritical
assembly by the spallation and fission reactions. Lead-bismuth is considered the
leading candidate for the liquid-metal spallation target for nuclear transmutation
D. Ito (*) • Y. Saito
Research Reactor Institute, Kyoto University, 2-1010 Asashiro-nishi,
Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
e-mail: itod@rri.kyoto-u.ac.jp
K. Hase
Power Systems Company, Toshiba Corporation, Kawasaki, Japan
© The Author(s) 2015
K. Nakajima (ed.), Nuclear Back-end and Transmutation Technology for Waste
Disposal, DOI 10.1007/978-4-431-55111-9_10
95