Study on the Influence of Inflow Direction on the Entrainment Effect of Blockages in the Open Intake Channel of Nuclear Power Plants

In recent years, frequent blockage of water intake structures at nuclear power plants (NPPs) by marine organisms has increased the risk of cooling source loss for the plants. Optimizing the layout of water intake structure to actively avoid or divert blockages near the intake entrance is one of the effective measures for cooling source risk prevention and control, and relevant research remains scarce at present. Taking a certain NPP as the research object, this paper simulates the flow field and particle transport in the sea area around the water intake based on a hydrodynamic-particle coupling model. A method for determining the maximum water source range and critical tidal conditions under risk source uncertainty is proposed. The flow pattern and entrainment risks of different open channel inlet types are compared. The results show that when the water intake open channel is arranged perpendicular to the ambient flow, a large recirculation zone exists at the intake entrance. Simply increasing the width at the intake entrance by expanding the local opening has an insignificant effect on reducing the water intake velocity and entrainment risk, while adopting additional side opening intake plays a certain role in dispersing the water intake entrainment intensity. The research results provide a basis for the optimal design and operation of water intake at NPPs.