Corrosion of Thermally-Oxidised Copper Materials in Chloride and Sulphide Solutions

Abstract

One of the main components in Canada’s nuclear waste plan is the used fuel container, a copper-coated carbon steel capsule to be buried deep underground at the depth of at least 500 m. This container is designed to isolate used fuel from the environment over its expected million-year lifespan. Extensive previous research has been performed on the corrosion of pristinely polished copper samples in aqueous environments, particularly in the presence of sulphide which could be generated via microbial activity in a deep geological repository. This research aims to investigate the formation of sulphides on copper that has been thermally oxidised in order to simulate the potential early-stage environment of the planned repository. The characteristics of the corrosion film produced on thermally oxidised copper surfaces in an aqueous sulphide solution are to be evaluated. This is intended to assist in a more complete description of the long-term corrosion behaviour of the containers compared to pristine copper surfaces.