2016 | ANNUAL REPORT 87 Figure 2. The magnified view of the “A1” area marked in Figure 1, showing the microstructure of the (U,Mo)Alx layer. These microstructural changes degrade fuel thermal conductivity, increase fuel temperature, and eventually lead to excessive fuel swelling. In order to improve the fuel’s irradiation performance, it is critical to adjust fuel fabrication parameters based on the correct understanding of the causes of the microstructural changes. Heavy ion irradiation was employed to screen fuel fabrication variables and to investigate separate effects of irradiation behavior of U-Mo/ The characterization experiments at CAES revealed a lot of new information of the microstructure of irradiated U-Mo fuel. — BeiYe, Materials Scientist Al dispersion fuels. By comparing the post-irradiation examination (PIE) results of carefully selected samples, a qualitative assessment of the effects of dose, dose rate, U-Mo grain size, irradiation temperature, and Mo contents on U-Mo/Al irradiation behavior can be obtained. The characterization results of ion irradiated fuels will be used in designing the next irradiation test in reactor.