Improvements in High Temperature Gas Cooled Reactor Modeling Capabilities in the Pronghorn Code

This report details the improvement of pebble bed reactor modeling capabilities in the Pronghorn code in fiscal year 2022. The following accomplishments are reported: • DeploymentofweaklycompressiblefinitevolumeformulationtotheHTR- PM reference plan model. • Enable modeling of stagnant gas gaps in the finite volume formulation. • Enable using all Pronghorn correlations available in the finite element version in the finite volume version. • Modeling of decay heat in pebble bed reactors. • Simplifying the input for multiphysics equilibrium core calculations and significant reduction of execution time. • Implementation of advanced correlations developed by the Center of Excellence for Thermal-Fluids Applications in Nuclear Energy. In addition, this report includes a development plan for Pronghorn and associated NEAMS tools for prismatic gas-cooled reactors.