Experimental study of two-phase flow oscillations in a natural circulation loop

Resumo

This work aims to investigate experimentally the oscillations during the operation of a natural circulation loop, designed to meet the single and two-phase flow similarity criteria to a typical Passive Residual Heat Removal (PRHR) system of an Advanced Pressurized Water Nuclear Reactor (APWR). The loop was one-tenth scale in height and operated at atmospheric pressure. It was comprised of a cylindrical vessel with descending tube, a core barrel housing electrically heated rods, and upper and lower plena interconnected to a seven-tube shell heat exchanger by hot and cold pipe legs. A data acquisition and control system was provided, including a power control and instrumentation, in order to permit variations of the power to the electrically heated rods, as well as to acquire flow rate, pressure and temperature data in a timely  manner.