Project Lead: Zhenyu Fei
The behavior of Accident Tolerant Fuel (ATF) cladding concepts in test reactors is critical to determining their performance in commercial reactors. While in-core experiments are of high value, autoclave experiments provide a greater opportunity to test samples in ways that are difficult to do in reactor or characterize after neutron exposure. This portion of the project will focus on experiments designed to determine the response of key cladding and cladding coating concepts that contain intrinsic or manufactured defects in the coating and are subject to stresses similar to what may occur in service. Execution of these experiments will enable decoupling the effects of irradiation and corrosion when correlated to the in-pile experiments and systematic determination of the correlation between defect severity and corrosion susceptibility in key cladding and cladding coating concepts. Cladding concepts to be studied in autoclave experiments include Zirlo tubing coated with Physical Vapor Deposition (PVD) Cr coating (2 sources) and SiC/SiC composite tubing with FeCrAl+Cr metal coating in PWR, and Zircaloy-2 tubing coated with Cr/FeCrAl coating and SiC/SiC composite tubing with FeCrAl+Cr metal coating in BWR.
To characterize and analyses evaluation of the corrosion product formation, it will use scanning electron microscopy (SEM) to show the performs in conjunction with elemental mapping and use x-ray energy dispersive spectroscopy (EDS) before and after oxidation along the defects. Then it will use Focused Ion Beam (FIB) to show serial cross-sectioning to build high-resolution 3D contrast. Transmission electron microscopy (TEM) samples extracted from the surface after exposure may also be used to evaluate the defect-coating-cladding interface. It also is a fine spot to use Scanning Transmission Electron Microscope (STEM) and Electron Energy Loss Spectroscopy(EELS) technology to provide spatially resolved microanalysis of a microelectronic device at the nanometer scale, which has excellent lateral resolution (~1nm) that allows mapping of non-planar features.