Effect of Surface Roughness on the Oxidation and Hydriding Behaviour of Zircaloy-4

Abstract

Fuel cladding tube is one of the most critical parts in the core of a nuclear reactor. It should be manufactured to satisfy a very strict clearances and material quality requirements. In conventional pressure water reactors like CANDU, Zircaloy-4 is being used for fuel cladding. In the reactor`s environment, Deuterium or Hydrogen can ingress and form hydrides in the cladding tube. There is no in-depth study of surface roughness effects on the properties of cladding tubes, however surface condition may affect oxidation, hydride formation and mechanical properties. In this study, the effect of surface oxide layer on hydride formation has been studied. It was demonstrated that the surface of oxide layer might act as a protective layer against hydrogen ingress.