The Nuclear Waste Management Organization is responsible for the implementation of Adaptive Phased Management, the federally-approved plan for the safe long-term management of Canada’s used nuclear fuel. Under this plan, used nuclear fuel will ultimately be placed within a deep geological repository in a suitable host rock formation.

The repository’s engineered barrier system (EBS) comprises the used fuel container and engineered sealing materials. The EBS is a key component of the design of the underground repository. The Canadian EBS consists of a carbon-steel, copper-coated used fuel container that is encapsulated within a bentonite buffer box.

Corrosion of copper and steel in the postclosure environment of a deep geological repository is expected to be very slow. This paper presents an estimate of these corrosion rates, forming the basis for assessing postclosure safety of a repository system and building confidence in the long-term performance of a Canadian repository for used nuclear fuel.