Nuclear Science User Facilities 88 Accomplishments TEM specimens of irradiated U-Mo/Al dispersion fuel were fabricated using the FEI Quanta focused ion beam (FIB) and characterized at theTecnai STEM at the MaCS at CAES. Several 20 × 20 × 10 µm3 U-Mo cubes were lifted out using the FEI Quanta FIB for synchro- tron irradiation characterization at the APS MRCAT Line at Argonne National Laboratory.AdditionalTEM specimens were prepared from un-irradiated U-Mo fuel using the FIB for in-situ irradiation study at the IVEM Facility at ANL.All FIB prepared samples were readied by the team with the great help of Jatu Burns. JoannaTaylor helped a great deal in shipping and handling the radioactive samples. Future Activities TheTEM study performed in 2016 revealed the microstructure of heavy ion irradiated U-Mo at certain irradiation temperature and dose rate.We will expand the investigation to samples irradiated at different temperatures and dose rates. Publications [1.] B.Ye, L. Jamison, S. Bhattacharya, A.Yacout, “TEM Characterization of U-Mo Irradiated with High- Energy Xe Ions,”Transaction of ANS Nuclear Society 114, (2016) 1285–1288. Figure 3. The magnified views of the “A2” area marked in Figure 1 taken at the (a) underfocus and (b) overfocus conditions, showing the high density nano-bubbles inside fuel grains. a) b)