We, for the first time, observe ZrO8 complex in Zr-doped UO2, which is a corium structure, using experimental characterization integrated with first-principle computational validation. Atomic level structure of U1−yZryO2 pellets (y = 0.01, 0.03, 0.05, and 0.1) is identified using Raman spectroscopy measurement and X-ray diffraction pattern analysis. The lattice constants shrink with increasing Zr doping levels, which consistently represents in the positive shift of T2g Raman vibration peak around 445 cm−1. More interestingly, conventionally unknown new Raman peak appears around 598 cm−1, which has not been observed in neither a pure ZrO2 nor UO2 doped with tetravalent elements other than Zr. We unveil that the new peak originates from ZrO8-type complex formed on the fluorite UO2. Our study provides precise understanding on the formation mechanisms and material properties of the corium in the hypervalent oxide.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Nuclear Energy and Engineering
- Fuel Technology
- Energy Engineering and Power Technology