Nuclear Instruments and Methods in Physics Research A 542 (2005) 168–174 Application of high frame-rate neutron radiography to liquid-metal two-phase flow research Y. Saito a , K. Mishima a,Ã , Y. Tobita b , T. Suzuki c , M. Matsubayashi d , I.C. Lim e , J.E. Cha e a Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan b O-arai Engineering Center, Japan Nuclear Cycle Development Institute, Narita, O-arai, Ibaraki 311-1393, Japan c Institut fu¨r Kern und Energietechnik, Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe, Germany d Tokai Establishment, Japan Atomic Energy Research Institute, Naka, Tokai, 319-1195 Ibaraki, Japan e Korea Atomic Energy Research Institute, Dukjin-dong ,Yuseong, Daejeon 305-353, Korea Available online 2 February 2005 Abstract Liquid metal two-phase flows in metallic vessels were studied by using high frame-rate neutron radiography. Both a bubble column and a gas-lift loop arrangement have been considered. Liquid velocity field of two-phase flow in a flat bubble column with rectangular cross-section was measured precisely by the particle tracking velocimetry. In a gas-lift loop, simultaneous measurements of void fraction by using high frame-rate neutron radiography and four-sensor probe were also performed to observe the bubble-probe interaction. Asymmetric Abel inversion was applied to compare the radial void fraction profiles. Measured radial void fraction profiles obtained by neutron radiography and electrical conductivity probe agreed well with each other. From these measurements, the measurement error and basic characteristics of gas–liquid metal two-phase flow were clarified. r 2005 Published by Elsevier B.V. PACS: 47.80.+v; 83.10.Lk; 83.50.Lh Keywords: Neutron radiography; Liquid-metal; Mutilphase flow; Interfacial area concentration; PTV 1. Introduction The detailed modeling of liquid-metal two-phase flow is a necessary prerequisite not only for safety analysis of liquid-metal fast breeder reactors (LMFBRs) [1] but also for the development of liquid-metal magneto-hydro-dynamics (MHD) system [2]. Liquid-metal two-phase has a larger liquid-to-gas density ratio and higher surface tension in comparison with those of ordinary two-phase flows such as air–water flow. In order to predict the flow behavior of a gas–molten metal ARTICLE IN PRESS www.elsevier.com/locate/nima 0168-9002/$-see front matter r 2005 Published by Elsevier B.V. doi:10.1016/j.nima.2005.01.095 Ã Corresponding author. Tel.: +81724512449; fax: +81724512637. E-mail address: mishima@rri.kyoto-u.ac.jp (K. Mishima).