Pressure drop and flow characteristics in partially blocked wire wrapped rod bundles

One of the fuel assembly designs considered for liquid metal-cooled fast reactors (LMFR) uses wires helically wrapped around fuel pins as spacers. The understanding of the coolant behavior in LMFR fuels under the influence of a partially blocked flow area is required for a correct safety assessment. Accumulation of debris or cladding deformation may generate a partial or total flow blockage of coolant channels at different locations. Unsteady Reynolds-Averaged Navier-Stokes (URANS) is applied using different turbulence models to predict the axial friction factor under the presence of blockages. Results are compared with experiments. The different turbulence models presented a variable performance for the blockage scenarios under study, finding k - is an element of Realizable the recommended model for turbulent regime and k - omega SST the recommended model at transition regime. A Large Eddy Simulation was also implemented to simulate the case with the largest blocked area finding its results in reasonable agreement with the experiments. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The design of fuel assemblies for liquid metal-cooled fast reactors is crucial for safety assessment, especially in considering the effects of flow blockages on coolant behavior. Different turbulence models were used to predict axial friction factors under blockage scenarios, with varying performance observed. Large Eddy Simulation was also implemented to simulate cases with significant blockage areas, showing reasonable agreement with experimental results.