SUMMARY

The proposed research will develop a methodology for modeling and simulations of Advanced High Temperature Reactor (AHTR). AHTR is a Fluoride salt-cooled High temperature Reactor (FHR) with hexagonal prismatic fuel assemblies with fuel plates. The fuel plates use TRISO fuel particles contained within fuel stripes, creating what is commonly referred to as a “double heterogeneous” geometry. This type of geometry is challenging to model due to its level of complexity.
Besides neutronics, an important component of core analysis is thermal hydraulic performance. This work will account for heat transfer within fuel assemblies as well as change in coolant density as it flows through the core. Additionally, this work will account for the temperature change by implementing thermal expansion capabilities for geometric features and corresponding change of respective material densities.
The objective of this work is to create a practical modeling tool which can adequately capture coupled core physics, thermal hydraulic, and thermal expansion behaviors of AHTR over a fuel cycle. Most of previous studies have homogenized TRISO particles to eliminate the double heterogeneity, but this work will maintain the explicit geometry. This work will use the resulting model to conduct a 3D full-core depletion analysis on the AHTR core to demonstrate its capabilities and illustrate its value as a design tool for future AHTR studies.