Advanced Calculation Tools to Simulate Fuel Fragment Relocation and Dispersal in Loss Of Coolant Accident Scenarios
Abstract
Advanced calculation tools are being developed within CEA's PLEIADES software platform to model fuel fragmentation, relocation, and dispersal (FFRD) during Loss of Coolant Accident (LOCA) scenarios. These tools support the analysis of FFRD tests performed by the international community within the HRP, SCIP, and other experimental programs. Their objective is to improve the understanding and characterization of these tests and to compare them with representative LOCA transients. The numerical approach presented in this paper couples the Discrete Element Method (DEM), used to describe fuel particle motion, with the Lattice Boltzmann Method (LBM), which resolves fluid flows at the sub-granular scale and enables twoway fluid-particle coupling. This coupling accounts for the hydrodynamic forces exerted by the fluid on each particle, the reaction forces exerted by particles on the fluid.A first 2D proof-of-concept calculation scheme is used to perform a qualitative sensitivity study, assess the successive stages of potential particle expulsion, and identify current modeling limitations. Key parameters-such as gas volume, rod and plenum pressure and temperature, fuel-column permeability, and breach size-are investigated together with their effects on the main quantities of interest, namely the amount and size distribution of fragments ejected into the primary circuit. Because 2D simulations have demonstrated their scientific value, a 3D calculation scheme is now being implemented in a massively parallel high-performance computing tool. This new HPC capability will enable more detailed sensitivity studies and provide the international community with support for test specification and interpretation. Overall, this work presents an innovative approach to FFRD modeling by combining fuel performance calculations with advanced numerical methods to improve understanding of the underlying physical mechanisms. The resulting insights will contribute to international research and development in this field and support nuclear safety demonstrations.
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BibTeX
@misc{collard2026advanced,
title = {{Advanced Calculation Tools to Simulate Fuel Fragment Relocation and Dispersal in Loss Of Coolant Accident Scenarios}},
author = {Bruno Collard and Guillaume Bareigts and Raphaël Prat and Vincent Topin and Emmanuelle Muller and Duc Chung Vu and Lhassan Amarsid},
howpublished = {HAL},
year = {2026},
month = oct,
url = {https://cea.hal.science/cea-05845887v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Advanced Calculation Tools to Simulate Fuel Fragment Relocation and Dispersal in Loss Of Coolant Accident Scenarios
AU - Bruno Collard
AU - Guillaume Bareigts
AU - Raphaël Prat
AU - Vincent Topin
AU - Emmanuelle Muller
AU - Duc Chung Vu
AU - Lhassan Amarsid
PY - 2026
DA - 2026/10/30
PB - HAL
UR - https://cea.hal.science/cea-05845887v1
AB - Advanced calculation tools are being developed within CEA's PLEIADES software platform to model fuel fragmentation, relocation, and dispersal (FFRD) during Loss of Coolant Accident (LOCA) scenarios. These tools support the analysis of FFRD tests performed by the international community within the HRP, SCIP, and other experimental programs. Their objective is to improve the understanding and characterization of these tests and to compare them with representative LOCA transients. The numerical approach presented in this paper couples the Discrete Element Method (DEM), used to describe fuel particle motion, with the Lattice Boltzmann Method (LBM), which resolves fluid flows at the sub-granular scale and enables twoway fluid-particle coupling. This coupling accounts for the hydrodynamic forces exerted by the fluid on each particle, the reaction forces exerted by particles on the fluid.A first 2D proof-of-concept calculation scheme is used to perform a qualitative sensitivity study, assess the successive stages of potential particle expulsion, and identify current modeling limitations. Key parameters-such as gas volume, rod and plenum pressure and temperature, fuel-column permeability, and breach size-are investigated together with their effects on the main quantities of interest, namely the amount and size distribution of fragments ejected into the primary circuit. Because 2D simulations have demonstrated their scientific value, a 3D calculation scheme is now being implemented in a massively parallel high-performance computing tool. This new HPC capability will enable more detailed sensitivity studies and provide the international community with support for test specification and interpretation. Overall, this work presents an innovative approach to FFRD modeling by combining fuel performance calculations with advanced numerical methods to improve understanding of the underlying physical mechanisms. The resulting insights will contribute to international research and development in this field and support nuclear safety demonstrations.
ER -