Development of advanced neutronics/thermal-hydraulics coupling simulation system, 9; Development of measurement method for gas-liquid two-phase flow inside a fuel bundle to obtain code validation data

Ono, Ayako ; Okamoto, Kaoru*; Makino, Yasushi*; Hosokawa, Shigeo*; Yoshida, Hiroyuki  

JAEA has been developing an advanced neutronic/thermal-hydraulics coupling simulation system. In the system, the detailed thermal-hydraulics codes JUPITER and TPFIT, which are based on an interface-capturing method, will be adopted to simulate thermal-hydraulics in a fuel bundle. The experimental data and findings relating to the two-phase flow in a fuel bundle are needed to validate JUPITER and TPFIT. In this study, we propose a new measurement method to measure the bubbly flow in a narrow channel, such as a subchannel, by combining laser-doppler velocimetry and photodiodes. The proposed measurement method is cross-checked by a conductance probe and is confirmed for its validity.