Author(s): Zhang Hao; Wang Tao; Fu Hui; Pan Jiajia; Chen Jian

Linked Author(s):

Keywords: Hot water recirculation; Thermal mixing; Frazil ice control; CFD modeling; Intake channels

Abstract: Frazil ice clogging in open intake channels poses a critical threat to the safe operation of nuclear power plants in cold regions. To mitigate this risk, hot water recirculation systems are often employed to raise inlet water temperatures and suppress ice formation. This study utilizes a three-dimensional CFD model to optimize the design and operation of such systems, specifically examining the hydraulic behavior and thermal mixing characteristics within the intake channel and pump house. We systematically evaluated the effects of varying recirculation flow ratios and discharge nozzle configurations on the resulting temperature fields. The simulations reveal that while higher recirculation rates increase the bulk water temperature, the spatial uniformity of thermal mixing—which is crucial for effective ice control—is primarily governed by the nozzle arrangement. Increasing the nozzle count at a constant flow rate significantly enhances mixing near the intake, thereby improving ice melting efficiency. Furthermore, the analysis identifies non-uniform flow distribution across branch pipes driven by pressure gradients in the main header, underscoring the importance of precise hydraulic design. These findings provide quantitative guidelines for optimizing recirculation strategies to ensure reliable winter operation.

DOI:

Year: 2026