Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Irradiation Induced Grain Refinement in Low Temperature U-Mo Metallic Fuels" By Alejandro L. Figueroa Purdue MSE Preliminary Exam Advisor: Professor Maria A. Okuniewski ABSTRACT Uranium molybdenum based fuels are currently being qualified as a replacement for high enrichment fuels, in high performance research and test reactors, as a global threat reduction effort. Irradiation induced grain refinement is currently being investigated in low operating temperature (<0.4Tm) nuclear fuels due to its association to an increase in swelling rates. Uranium molybdenum alloys are of interest due to their accumulation of fission gasses into an ordered nano-bubble superlattice. The superlattice has been observed to suppress the formation of the defect structures typically associated with irradiation induced grain refinement. This behavior limits the ability to correlate the observed mechanisms with historical data. Understanding the underlying mechanisms of irradiation induced grain refinement will aid in fuel performance by tailoring fuel design to suppress the transformation, and accounting for the formation in operating codes. This review discusses the current efforts in characterizing the transformation mechanism, its effect on the microstructure, and modelling of the phenomenon. Date: Friday, November 15, 2019 Time: 8:00 A.M. Place: ARMS 1021