Analysis of Blockage Accident of Lead-Based Fast Reactor Single-Box Fuel Assembly Based on CFD

The corrosion products produced during the operation of the lead-based reactor may be deposited in the reactor, resulting in the occurrence of flow plugging accident. Based on the computational fluid dynamics software Ansys Fluent, the effects of different blockage area, thickness, type and position on the deterioration of heat transfer and the properties of flow field in current plugging accident are analyzed. The results show that the increasing of blockage area will increase the reflux area, which makes the temperature fall more slowly and the heat transfer worsen obviously; the increasing of the blockage thickness will lead to the increasing of the maximum temperature of coolant and cladding, which can easily lead to cladding damage; the coolant in the porous medium blockage passes at a lower flow rate, which alleviates the influence of blockage and does less harm than the solid blockage. The local warming caused by the blockage located in the middle of the active area is more obvious and more harmful than that caused by the blockage in the entrance and exit of the active area.