As part of an effort to develop low enriched U-Mo fuels for application in research and test reactors, the Materials Management and Minimization Reactor Conversion (MMMRC) Program utilizes detailed high-resolution microstructural characterization techniques to characterize irradiated U-Mo nuclear fuel plates. This includes using techniques like transmission electron microscopy, atom probe tomography, electron energy loss spectroscopy, and electron backscattered electron diffraction to uncover the microstructure of U-Mo alloys, and other materials of construction, after irradiation. The data generated using these techniques is imperative for developing a fundamental understanding of the irradiation performance of this fuel under a variety of irradiation conditions. Information like that generated from this work is key for improving computer modeling of the fuel performance under irradiation. This presentation will discuss how recent results can be used to improve understanding of phenomena like recrystallization, grain growth, radiation stability, and swelling of irradiated U-Mo fuel and other fuel plate materials.