Most fast reactor designs foresee wire-wraps as spacer between the fuel rods. The safety analyses of such reactors requires thorough understanding of the flow and heat transport in such wire-wrapped fuel assemblies. In the past, this relied on experimental investigations, derived correlations and in addition computational analyses on 0- or 1-dimensional system or sub-channel scale. Nowadays, Computational Fluid Dynamics (CFD) has become an integral tool for the advanced reactor designer allowing simulations in 3 dimensions. However, the application of CFD tools needs to be validated. This paper will discuss the ongoing efforts at NRG in the Netherlands on validation of CFD tools for wire-wrapped fuel assembly simulations for flow and heat transport.