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 safety of the repository is based on the combination of the geology, engineered design, careful operations, and quality assurance processes including review and monitoring. The ability of the repository to safely contain and isolate used nuclear fuel is achieved by multiple barriers, these being the ceramic used fuel pellet, the fuel sheath, the robust long-lived container, a series of clay-based seals and backfill material, and the rock formation within which the repository will be located.

Before a specific site is identified, hypothetical sites and conceptual repository designs are used to illustrate the ability of the multi-barrier system to meet or exceed the regulatory requirements imposed by the Canadian Nuclear Safety Commission. This paper summarizes an illustrative postclosure safety assessment of a conceptual deep geological repository situated in a hypothetical crystalline rock setting. The purpose of the assessment is to determine potential effects of the repository on the health and safety of persons and the environment. Results for the Normal Evolution Scenario, associated sensitivity cases, disruptive scenarios, and probabilistic analyses are compared against interim acceptance criteria established for the protection of persons and the environment from potential radiological hazards.