Simulation of fuel dispersion in the MYRRHA-FASTEF primary coolant with CFD and SIMMER-IV

Highlights • A comparison between CFD and system codes applied to long-term dispersion of fuel particles inside the MYRRHA reactor is proposed. • Important accumulations at the free-surface level are to be expected. • The risk of core blockage should not be neglected. • Numerical approach and modeling assumptions have a strong influence on the simulation results and accuracy. Abstract The objective of this work is to assess the behavior of fuel redistribution in heavy liquid metal nuclear systems under fuel pin failure conditions. Two different modeling approaches are considered using Computational Fluid Dynamics (CFD) codes and a system code, applied to the MYRRHA facility primary coolant loop version 1.4. Two different CFD models are constructed: the first is a single-phase steady model prepared in ANSYS Fluent, while the second is a two-phase model based on the volume of fluid (VOF) method in STARCCM+ to capture the upper free-surface dynamics. Both use a Lagrangian tracking approach with oneway coupling to follow the particles throughout the reactor. The system code SIMMER-IV is used for the third model, without neutronic coupling. Although limited regarding the fluid dynamic aspects compared to the CFD codes, comparisons of particle distributions highlight strong similarities despite quantitative discrepancies in the size of fuel accumulations. These disparities should be taken into account while performing the safety analysis of nuclear systems and developing strategies for accident mitigation.

@Article{BPEMV15,
  author       = {Buckingham, S. and Planquart, P. and Eboli, M. and Moreau, V. and Van Tichelen, K.},
  title        = {Simulation of fuel dispersion in the MYRRHA-FASTEF primary coolant with CFD and SIMMER-IV},
  journal      = {Nuclear Engineering and Design },
  volume       = {295},
  pages        = {74-83},
  month        = {december},
  year         = {2015},
  publisher    = {ELSEVIER},
  keywords     = {MYRRHA, LBE, CFD},
  doi          = {10.1016/j.nucengdes.2015.08.018},
  url          = {https://publications.crs4.it/pubdocs/2015/BPEMV15},
}