NSUF 12-483: Transmission Electron Microscopy Study of the Microstructure Evolution in Kr Irradiated UO2

To simulate fission fragments damage and connect the microstructure with thermal transport behavior in UO2, 1.8 MeV Kr ion beam at University of Illinois has been used to irradiate single crystal and polycrystalline UO2. The damage depth is around 1 micron, which is good for both microstructure study and thermal transport measurement. The rapid turnaround experiment is to clarify the microstructure of UO2 before and after irradiation and high-temperature annealing. The TEM samples of UO2 before and after irradiation tests will be prepared by focused ion beams and then studied by 300 kV Tecnai TF30-FEG TEM at CAES. Black dot defects at size of about 1 nm will be examined using weak beam dark field imaging. Dislocation loops and dislocation segments or dislocation networks will be examined by both bright field and dark field image techniques and the Burgers vector will be analyzed. Cavities or bubble evolution in the grain and at GB will be investigated by the underfocus and overfocus image techniques. The comparison between the microstructure features of UO2 under various doses and annealing temperatures will shed light on both the dose and temperature effects on defect and bubble formation and evolution. Further, the experimental microstructure characterization is to provide a fundamental foundation for the atomic-level modeling, which are conducted at INL, Purdue University and University of Florida. The microstructure evolution will be connected to the thermal transport change measured at INL. This rapid turnaround project includes FIB sample preparation, and TEM /EDS/EELS characterization, experimental data analysis and final report, which will take about 2 months in total. The proposed research will be performed in about 3 weeks at CAES, with 6 days for sample preparation and grain boundary characterization on the FIB/EBSD and 10 days for TEM investigations.

Additional Info

Field	Value
Abstract	To simulate fission fragments damage and connect the microstructure with thermal transport behavior in UO2, 1.8 MeV Kr ion beam at University of Illinois has been used to irradiate single crystal and polycrystalline UO2. The damage depth is around 1 micron, which is good for both microstructure study and thermal transport measurement. The rapid turnaround experiment is to clarify the microstructure of UO2 before and after irradiation and high-temperature annealing. The TEM samples of UO2 before and after irradiation tests will be prepared by focused ion beams and then studied by 300 kV Tecnai TF30-FEG TEM at CAES. Black dot defects at size of about 1 nm will be examined using weak beam dark field imaging. Dislocation loops and dislocation segments or dislocation networks will be examined by both bright field and dark field image techniques and the Burgers vector will be analyzed. Cavities or bubble evolution in the grain and at GB will be investigated by the underfocus and overfocus image techniques. The comparison between the microstructure features of UO2 under various doses and annealing temperatures will shed light on both the dose and temperature effects on defect and bubble formation and evolution. Further, the experimental microstructure characterization is to provide a fundamental foundation for the atomic-level modeling, which are conducted at INL, Purdue University and University of Florida. The microstructure evolution will be connected to the thermal transport change measured at INL. This rapid turnaround project includes FIB sample preparation, and TEM /EDS/EELS characterization, experimental data analysis and final report, which will take about 2 months in total. The proposed research will be performed in about 3 weeks at CAES, with 6 days for sample preparation and grain boundary characterization on the FIB/EBSD and 10 days for TEM investigations.
Award Announced Date	2014-02-10T00:00:00
Awarded Institution	None
Facility	None
Facility Tech Lead	Yaqiao Wu
Irradiation Facility	None
PI	Lingfeng He
PI Email	[email protected]
Project Type	RTE
RTE Number	483