This thesis is part of the MUZIC-3 (Mechanistic Understanding of Zirconium Corrosion) project, with the overall goal to understand the in-reactor corrosion and hydrogen pick-up mechanisms of zirconium alloys. Zirconium alloys are commonly used for fuel cladding and support structures in light water reactors but suffer from aqueous corrosion in service that can limit the operating lifetime and the effective burnup of the fuel. Understanding the mechanisms of corrosion, especially under irradiation, is thus of great importance for the development of accurate, physically based lifetime prediction models for cladding materials, and providing information for the design of new corrosion-resistant alloys.