CFD application in nuclear engineering/industy

The last decade has seen an increasing use of three-dimensional CFD codes to predict steady state and transient flows in nuclear reactors. The reason for the increased use of multidimensional CFD methods is that a number of important phenomena such as pressurized thermal shocks, boron mixing, and thermal striping cannot be predicted by traditional one dimensional system codes with the required accuracy and spatial resolution.

CFD codes contain empirical models for simulating turbulence, heat transfer, multi-phase flows, and chemical reactions. Such models must be validated before they can be used with sufficient confidence in NRS applications. The necessary validation is performed by comparing model results against trustworthy data. However, in order to obtain a reliable model assessment, CFD simulations for validation purposes must satisfy strict quality criteria. For instance, numerical errors caused by too coarse numerical grids should be separated from shortcomings of the physical models to avoid wrong conclusions about model performance.

CFD simulations are shown with an emphasis on validation in areas such as: heat transfer, buoyancy, multi-phase flows, natural circulation, free-surface flows, turbulent mixing, and complex geometries. These topics are related to NRS-relevant issues such as: pressurized thermal shocks, boron dilution, hydrogen distribution, induced breaks, subcooled boiling, thermal striping, etc.