Zirconium alloys are widely used in light water reactors as fuel cladding, acting as the
primary barrier between the nuclear fuel and the coolant, due to the excellent neutron
transparency, acceptable corrosion resistance and good mechanical properties of the
zirconium. While in service these alloys degrade due to exposure to high temperature
aqueous environments and strong radiation fields. As these Zr alloy components often
perform critical safety roles, their degradation in service must be understood. In this thesis I
use the capabilities of the NanoSIMS 50L, a magnetic sector mass spectrometer capable of
nanoscale lateral resolution, to analyse the distribution of hydrogen and oxygen in corroded
Zircaloy-4 and Zircaloy-2 and the impact that irradiation has on oxide growth and
distribution of oxygen in the oxide layer.