High-Resolution Pebble Bed Data at Low Flow Conditions

The project seeks to address significant gaps in the modeling and simulation of advanced reactors, in particular FHRs and HTGRs (Fluoride Cooled High Temperature Reactors and High Temperature Gas Reactors). We aim to develop a high resolution numerical and experimental fluid dynamic and heat transfer dataset for pebble bed reactors at low flow conditions encountered in accident scenarios. The dataset will be used to benchmark porous media codes at conditions for which experimental data currently does not exist and will allow development of improved models that account for the spatial distribution of the porosity. In order to achieve this goal, several innovations are sought including development and validation of thermal radiation transport modeling capabilities, a key heat removal process at low-flow conditions, within the high-fidelity code suite Cardinal. Cardinal has the unique capability to leverage Graphics Processing Units (GPUs), which enables to scale simulations to unprecedented sizes, including full core simulations. Data generated with Cardinal will be used to improve proous media models through a novel data reduction technique. Finally, we seek the development of a high resolution experiment featuring concurrent temperature and velocity measurements of natural convection in pebble beds. The data will be used to validate and develop further confidence in the high resolution numerical results obtained with Cardinal.