Speaker
Description
Understanding the degradation mechanisms of protective coatings used in nuclear fuel rods is critical for ensuring their long-term safety and performance under extreme environments. Under normal operational conditions, the fuel rods are exposed to temperatures of ~300 °C in water of high pressure (7 MPa). Even more critical is the event of a loss-of-coolant accident (LOCA) when the temperature can reach over 1000 °C in a water vapor environment. Covering the fuel rods with an oxidation resistant coating protects the Zr-based cladding which has an inherently poor oxidation resistance, thus increasing the lifetime during normal operation and prevents catastrophic failure during a LOCA. This project investigates the oxidation behaviour of Cr- and Nb-based coatings as a function of chemical composition and microstructure. To investigate oxidation behaviour, X-ray absorption spectroscopy (XAS) is employed as a powerful tool to provide invaluable insights into oxidation states, local atomic environments, and electronic structures of coating material. To study the oxidation behaviours evolution of coatings dynamically, in situ X-ray spectroscopy experiments are planned. By employing those in-situ/operando experiments, it is possible to simulate the real working conditions of nuclear fuel rods by heating the sample to the target temperature with steam environment. These advanced techniques will provide a comprehensive understanding of materials behaviour, ultimately contributing to the development of next-generation protective coatings for nuclear applications.