Experimental Investigation of Influence of Heating Distribution Variation of Riser Channel on Heat Transfer in Two Channels Facility

This study investigated how heat transfer occurs during pressurized conduction cooldown accidents (PCC) to understand the passive safety features of natural convection in prismatic modular reactors (PMR). PCC is a loss of flow accident, meaning the flow of working fluid to the reactor is suspended. In contrast to DCC (depressurized conduction cooldown), during PCC, high working fluid pressure is maintained. Understanding how reactor properties affect natural convection during PCC is crucial to passive safety. To study this phenomenon, a scaled down PMR model was designed by multiphase reactors engineering and applications laboratory (mReal) team at Missouri University of Science and Technology (S&T), consisting of upper and lower plenum connected by a riser and downcomer channel. Non-uniform heat flux was applied to the riser channel, simulating axial temperature distribution of the nuclear fuel in PMR. Air was used as coolant to study the effect of non-uniform heating on natural convection