Comprehensive Investigation of the Role of Nb on the Oxidation Kinetics of Zr-Nb Alloys

Abstract Waterside corrosion of zirconium alloys is currently the life-limiting degradation mechanism of fuel elements in pressurized-water reactor (PWR) systems. Today, PWRs use Zr-Nb fuel cladding designed to limit oxidation and hydrogen pickup. However, oxidation kinetics of Zr-Nb alloys can vary substantially depending on the Nb content and distribution, even in alloys of the same composition but different heat treatments. To elucidate the role of Nb on Zr-Nb oxidation kinetics and improve the fundamental understanding of Zr-Nb corrosion, nano-beam X-ray absorption near-edge spectroscopy (XANES), transmission electron microscopy (TEM), and application of the Coupled-Current Charge-Compensation (C4) Model have been performed in concert.