Development of capacitance void fraction measurement method for BWR test

Watanabe, Hironori; Tamai, Hidesada; Sato, Takashi; Shibata, Mitsuhiko ; Mitsutake, Toru*

In Boiling Water Reactor (BWR), reactor power, fuel conversion ratio and reactor cooling capacity changes by the void fraction in the core. We have developed a capacitance method (C method) to measure the void fraction under the condition of high temperature and high pressure of 7MPa, simulating reactor. This C method is based on the principle that the capacitance in the two-phase flow is a function of void fraction. Using this method, we can measure void fractions in real time, at all region of void fractions, and with a small error of measurement, which was not realized by usual techniques up to now.