Research on a New Method of Division Sub-Channel for Petal-Shaped Fuel Assembly and Turbulent Characteristics in Sub-Channels with Subcooled Boiling

Abstract

In this paper, a new sub-channel division method is proposed for petal-shaped fuel assemblies. This method is applied to a 3×3 fuel assembly, where sub-channels are classified,  and turbulent characteristics with subcooled boiling in the sub-channels are investigated. The results show that the mass flow flux increases significantly along the flow direction in the sub-channel BJ1, while it decreases in the sub-channel BJ5, with minimal changes observed in other sub-channels. The coolant flows toward the central channel. In the sub-channels surrounding the rods, the mass flow flux increases markedly along the flow direction in the sub-channel A1, while it decreases significantly in the sub-channel A3, with little change in other sub-channels. Coolant flows out from the sub-channels around the rods on the windward side along the convex arc of the petal rods, while coolant flows into the sub-channels around the rods on the leeward side.

Keywords: Small-scale nuclear reactor, Petal-shaped fuel rod, Sub-channel division method, Subcooled boiling, Numerical simulation