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In this project we utilize a combination of state-of-the-art soft X-ray spectroscopies to understand the chemical bonding between metal fission products (Pd and Ag) with coating layers in TRISO fuel particles (SiC and pyrocarbon). We are primarily focusing on an analysis of intermediate chemical phases at the interface, the intermixing/diffusion behavior, and the electronic interface structure as a function of material choice (metal and coating materials), temperature, and external stress. In the current first project year, we are beginning these investigations with the Pd/SiC interface, as discussed in the previous two quarterly reports. Our first experiments (both using our lab instrument as well as using high-brilliance synchrotron radiation at the Advanced Light Source (ALS) in Berkeley) indicate that the interface formation leads to three different carbon species, which are ascribed to a bulk species, an interface species, and “reacted” species due to intermixing at the interface. Furthermore, we find a significant charge transfer between Pd and Si, as evidenced by the synchrotron X-ray emission spectra presented in the previous report.


Chemical structure; Electronic structure; Metal-base fuel; Metal coating; Nuclear chemistry; Nuclear fuels; Palladium; Silicon carbide; X-ray spectroscopy


Chemistry | Nuclear | Nuclear Engineering | Oil, Gas, and Energy | Physical Chemistry