SUBJECT: Ph.D. Dissertation Defense
BY: Jim Wang
TIME: Friday, November 19, 2021, 9:00 a.m.
PLACE:, Virtual
TITLE: Coarse-mesh-based Reduced-Order Package for Multi-Physics Simulations of Nuclear Thermal Propulsion Reactor Cores
COMMITTEE: Dr. Dan Kotlyar, Chair (GT NRE)
Dr. Bojan Petrovic (GT NRE)
Dr. Mostafa Ghiaasiaan (GT NRE/ME)
Dr. Jon McWhirter (TerraPower)
Dr. Massimiliano Fratoni (UC Berkeley)


Among the various proposed space propulsion technologies, the nuclear thermal propulsion (NTP) system has been identified as the technology of choice for NASA’s mission to Mars due to its high efficiency in fuel performance. Most of the legacy NTP engine designs from NASA’s historical Rover/NERVA program relied on highly enriched (above 90% enrichment) uranium (HEU) fuel. Recent efforts focus on designing a high-efficiency engine that relies on high-assay low-enriched uranium fuel (HALEU with ~19.75% enrichment). To achieve high specific impulse and thrust to weight values, these new HALEU-based generations of NTP would require geometrical modifications associated with the elements’ thickness and pitch, as well as the core’s length and configuration. The evolution of current designs mandates setting up new experiments to alleviate some uncertainties; however, these are costly and not readily available. Therefore, there is a real need to complement these expensive experiments and capture multi-physics effects using numerical modeling and simulation tools. This dissertation introduces a steady-state OpenFOAM multi-physics package tailored for NTP core simulation. Denoted as NTPSteadyFOAM, this package consists of three sub-modules that model NTP fuel-to-coolant heat transfer, element-to-element heat transfer, and power generation through neutron diffusion. The multi-physics coupling approach is built upon an existing reactor solver, GeN-Foam, designed to tighten the coupling between thermal-hydraulics, neutronic, and other important feedback.