An experimental study of pool entrainment with side exit

Pool entrainment in upper plenum is an important safety related phenomenon in SBLOCA transient for advanced PWR plants like AP1000. Due to the unique geometric characteristics, the application of standard Kataoka model in the upper plenum/hotleg entrainment phenomena requires significant caution. Based on a careful review of recent pool entrainment studies, this research carried out an experimental study of air-water pool entrainment with and without side exit/outlet to better capture the prototypic geometry of upper plenum/hotleg arrangement. Total 150 sets of test data are obtained at various combinations of gas velocities and water levels. The test data covers several entrainment regions from low gas flux region to near saturation region. The results show that the side exit/outlet will reduce the entrainment rate in high gas flux region and near saturation region. The mechanism is analyzed using visualization and CFD simulation. Based on the experiment data, a new correlation of pool entrainment with side exit/outlet in high gas flux region is proposed.