Numerical study on surface corrosion deposition of fuel elements and its influence on flow heat transfer.

• The deposition model and the thermal resistance model of the deposits are verified. • The deposit growth and changes over a 500-day period in the fuel rod bundle channel are obtained. • The thermal resistance of the deposit increases rapidly once its thickness exceeds 30 μm. • The influence of different parameters on deposit growth and parameter changes is investigated. Corrosion of pressurized water reactors (PWR) in nuclear power plants can lead to serious safety hazards. This study aims to analyze the deposition of corrosion products using FLUENT software. Deposition models and thermal resistance models were developed, and the effects of deposits on the reactor's thermal–hydraulic characteristics were evaluated. Additionally, the impact of various parameters on deposition and thermal–hydraulic characteristics was examined. Results show that deposits accumulate extensively in the inlet section of the fuel cladding, while appearing as spot deposits in the outlet section. For deposit thicknesses below 30 μm, the surface temperature of the cladding gradually increases. However, when the thickness exceeds 30 μm, the surface temperature rapidly rises. Furthermore, the study reveals that the deposition amount decreases with increasing inlet flow velocity, exhibits an upward trend with higher inlet temperature, and increases with a higher wall heat flux density. This research provides important insights for understanding core deposition and thermal–hydraulic characteristics in nuclear reactor systems. It offers valuable guidance for enhancing safety and operational efficiency in nuclear power plants. [ABSTRACT FROM AUTHOR]