MESOSCALE SIMULATIONS OF THERMAL TRANSPORT IN W-UO2 CERMET FUEL FOR NUCLEAR THERMAL PROPULSION

Open Access
Author:
Ferreira F Sessim, Marina
Graduate Program:
Nuclear Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
November 17, 2017
Committee Members:
  • Michael Tonks, Thesis Advisor
  • Arthur Thompson Motta, Committee Member
  • Mary I Frecker, Committee Member
Keywords:
  • Nuclear Thermal Propulsion
  • CERMET
  • Thermal Conductivity
  • Heat Conduction
  • Tungsten
  • Uranium Dioxide
  • W-UO2
  • Nuclear Fuel
Abstract:
Nuclear thermal propulsion (NTP) provides constant power for long space missions, which is a tremendous benefit over chemical rockets. Therefore, a lot of effort in investigating different fuel concepts and geometries has been invested. For applications involving NTP or nuclear power, it is very important that the heat generated by the fissile nuclei can be quickly transferred to the coolant. It is then essential that the fuel has a high thermal conductivity so that minimum stored energy is left inside the fuel. In this project, the feasibility and thermal performance of a W-UO2 CERMET fuel were assessed. First, the microstructure behavior of this fuel was studied by analyzing Scanning Electron Microscopy images. The effective thermal conductivity was calculated at the mesoscale for a 3-dimensional microstructure using the MOOSE framework, which was mainly developed by the Idaho National Laboratory. Then, the results were compared with published literature and analytical solutions. The thermal conductivity calculated using MOOSE was approximately 20% lower than the proposed by the Bruggeman model. The thermal transport in different for 7, 19 and 61-channel fuel concepts were analyzed using the MOOSE framework. The temperature profile for each concept is provided. The 61-channel concept had the best performance due to a better cooling surface area ratio to the volume of fuel.