Raman and XPS characterization of fuel-cladding interactions using miniature specimens.

Laser Raman spectroscopy was evaluated as a tool for studying fuel-cladding chemical interactions at elevated temperatures. Materials and conditions were selected to simulate the interface of oxide fuels and fission products with high-temperature cladding materials for TRU-MOX fueled reactors. Both ex-situ and in-situ spectroscopy measurements were performed using polished HT-9 disks, uncoated and coated with yttria-stabilized zirconia, that were exposed to air oxidation at temperatures between 873-973K. Ex-situ measurements (under ambient conditions) were conducted to identify oxide phases, determine oxidation mechanisms and approximate film growth rates with an optimal signal-to-noise for the equipment used. Subsequently performed in-situ measurements were used to evaluate the sensitivity of the technique for measurements at elevated temperature in a hot-stage. Raman spectra were supported with x-ray photoelectron spectroscopy depth profiling. The results, which are for non-fueled materials in this study, illustrated a method for fast screening of candidate alloys with actinide-based MOX fuel mixtures.