Pronghorn is a Multiphysics Object-Oriented Simulation Environment (MOOSE) based thermal-hydraulics code developed at Idaho National Laboratory (INL) for advanced reactor analysis. It has been previously applied to model Pebble-Bed High Temperature Reactors (High Temperature Reactor (HTR)s), Liquid-Metal Cooled Reactors, and Molten Salt Reactors, among others. This work applies the coarse-mesh thermal hydraulics capabilities in Pronghorn to model Prismatic-Core HTRs. In particular, the Oregon State University (OSU)’s High Temperature Test Facility (HTTF) is modeled with Pronghorn. The HTTF is a 1:4 height scaled-down facility of General Atomics’ Modular High Temperature Gas-cooled Reactor. The report summarizes the following results obtained with Pronghorn: • Verification of the implementation of Churchill’s pressure drop in channels against analytical calculations. • Verification of energy-porosity formulation in Pronghorn for expected temperature rise across a heated assembly. • Study of mesh convergence for the weakly-compressible flow formulation in Pronghorn for a heated fuel assembly. • Demonstration of a 3D model of the full HTTF core using Pronghorn.
