Predictions of hydrodynamic characteristics and corrosion rates using CFD in the piping systems of pressurized-water reactor power plant

• CFD is used to model two piping systems in a PWR power plant.
• The species transport with molecular diffusivities was used in this investigation.
• Predicted corrosion rates are compared with measured data.
• There is good agreement between calculations and data with respect to the distribution trends of corrosion rates.

Corrosion represents the degradation of a material, due to chemical reactions with the surrounding environment. One of the degradation mechanisms is flow accelerated corrosion (FAC), which occurs in piping systems and leads to the thinning of large areas on pipelines, especially in nuclear power plants. Corrosion rates in elbows are usually higher than straight pipes, due to flow characteristics in elbows. Corrosion can cause pipe breakage, even plant shutdown or personnel injury. Therefore, the investigation of corrosion rates in a piping system is important in relation to nuclear power plants. Therefore, the objective of this study is to investigate the corrosion rate caused by mass transfer in two different piping systems using computational fluid dynamics. Measured data obtained from a PWR power plant will be compared with numerical predictions, which are employed for three-dimensional, turbulent single-phase flow model. A mass transfer model is used to calculate the species transport caused by molecular diffusivities in the piping systems. The results show that flowing velocities, static pressures and wall shear stresses affect the corrosion distributions, due to the secondary flows and a separation region. Comparison between the calculations and measured data on the walls of the elbows shows that the distribution trends of corrosion rates have good agreements. This investigation cannot only predict the corrosion distributions and the seriousness of the elbows for nuclear power plant, but also assist the plant staff on how to treat the problem of corrosion phenomenon.