| Abstract Scope |
Uranium-zirconium (U-Zr) fuels produce lanthanide fission products (FPs), such as Nd and Ce, which migrate to the fuel-clad interface during reactor operation and contribute to fuel-clad chemical interaction (FCCI). The FCCI region contains low-eutectic phases formed between the fuel and the Fe, as well as brittle phases formed due to the interaction of fission products (FPs) and the steel. It is known that most pure lanthanide FPs create a diffusion region of a size related directly to the parabolic rate law with respect to time in ferritic martensitic steel while below the X-Fe (X=Nd, Ce) eutectic temperature. However, the diffusion region growth rate and intermetallic phase fraction dependence on temperature has not been fully explored in these systems. In this study, diffusion couples of Ce-HT9 are tested at 520, 590, and 660 °C and Nd-HT9 couples are tested at 615, 685, 755 °C at time intervals between 1-48 hours. Diffusion parameters and phases are characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The mechanical properties of the simulated FCCI region are explored using nanoindentation. |