An experimental study of pool entrainment in high gas flux region

Pool entrainment is an important phenomenon in LOCA transient in both conventional and passive PWR plants. Kataoka and Ishii's pool entrainment model is widely used in small break LOCA and reactor transient analysis, but has limited validation against experimental data in high gas flux region. This paper is to report an experimental study of air-water pool entrainment with prototypic gas flux conditions of AP1000. The test section is 2200 mm long and 380 mm in diameter, and built by transparent material for visualization. The range of air flow superficial velocity is 0.98-5.41 m/s. The two phase mixture level is measured by Guided Wave Radar (GWR), and the water entrainment is recorded by weight measure after it is separated from entrainment separator. A correlation of pool entrainment in high gas flux region is proposed based on experimental data obtained in this study. The phenomenon of entrainment saturation is found in high gas flux region. The visualization indicates that pool entrainment in high gas flux region is in transition to jet/fountain flow, which might have strong exit effect.