Pre − test evaluation of a grid − spaced deformed fuel pin bundle

A code-to-code comparative study is conducted among four contributors (CRS4, ENEA, NRG, VKI) to simulate the Deformed Fuel Pin Simulator of NACIE-UP facility. The objective of the discussed numerical work is to support the planned experiments of the Deformed Fuel Pin Simulator that replicates operating conditions of the ALFRED reactor. For this purpose, a comparative study is carried out using the Computational Fluid Dynamics based framework. Specifically, four distinct numerical approaches are implemented by individual contributors to simulate the operation of the considered test section. In this, blind numerical computations are performed for three different reference test cases, which are later planned for experimental investigation. The influence of pin deformation and of different input parameters, such as the turbulence model and the turbulent Prandtl number, is discussed through independent sensitivity studies. In addition, the effect of distinct mass flow rates and power inputs is observed with the help of several local and global flow variables. The obtained flow-thermal characteristics are then further discussed and compared among all four participants. It is observed that, despite using dissimilar numerical frameworks, thermal measurements are accurately predicted for all considered test cases of low Prandtl number flow. These findings can be helpful to the heavy liquid modelling community that often relies on different numerical tools due to several computational constraints. Insights from the present work are helpful to understand the flow behaviour of liquid metal fast reactor and are intended to be used in a subsequent code-to-experiment comparison.

@Article{DRDPMPFL25,
  author       = {Dalvi, S. and Roelofs, F. and Di Piazza, I. and Puviani, P. and Moreau, V. and Profir, M. and Fiore, M. and Lopes, S.},
  title        = {Pre − test evaluation of a grid − spaced deformed fuel pin bundle},
  journal      = {Nuclear Engineering and Design},
  volume       = {443},
  pages        = {114293},
  month        = {november},
  year         = {2025},
  publisher    = {Elsevier},
  note         = {European Project ANSELMUS collaborative work },
  keywords     = {Liquid metal Fast Reactor, Deformed Fuel Pin Simulator, Grid spaced fuel assembly, CFD},
  doi          = {10.1016/j.nucengdes.2025.114293},
  url          = {https://publications.crs4.it/pubdocs/2025/DRDPMPFL25},
}