Experimental investigations of droplet carryover from the separator drum of an air-lift loop simulating a scaled-down AHWR

Entrainment of phases into each other in a two-phase Natural Circulation Loop is of critical concern in nuclear applications. Despite having serious consequences, such as, radioactivity contamination, hardly any focused study of droplet entrainment from the separator drum has been reported. Hence, a comprehensive experimental study has been performed on an air-lift loop, considering an Advanced Heavy Water Reactor (AHWR) as the prototype. Loop dimensions were obtained following a detailed scaling analysis incorporating natural circulation modelling methodology and entrainment analysis inside the drum. Carryover was observed to increase with air supply rate and generally with drum water level. Porous suppressor plates were employed to reduce droplet entrainment and approximately 94% carryover reduction was achieved for the highest air flow rate employed. Parametric studies characterized the suppressor plates well; carryover rate reduced with reduction in diameter and number of holes in the suppressor plates.

► Comprehensive experimental study on an air-lift loop, with an AHWR as the prototype. ► Loop dimensions estimated through scaling analysis incorporating entrainment inside the drum. ► Results indicate carryover to increase with air supply rate and generally with drum water level. ► Porous suppressor plates reduced carryover by 94% at the highest air flow rate. ► Carryover rate reduced with reduction in diameter and number of holes in the plate.