Postclosure Safety Assessment of a Deep Geological Repository for Canada's Used Nuclear Fuel

Abstract

This paper reports on elements of a postclosure safety assessment performed for a conceptual design and hypothetical site for a deep geological repository for Canada’s used nuclear fuel. Key features are the assumption of a copper used fuel container with a steel inner vessel, container placement in vertical in-floor boreholes, a repository depth of 500 m, and a sparsely fractured crystalline rock geosphere.

The study considers a Normal Evolution Scenario together with a series of Disruptive Event Scenarios. The Normal Evolution Scenario is a reasonable extrapolation of present day site features and receptor lifestyles, while the Disruptive Event Scenarios examine abnormal and unlikely failures of the containment and isolation systems.

Both deterministic and probabilistic simulations were performed.

The results show the peak dose consequences occur far in the future and are well below the applicable regulatory acceptance criteria and the natural background levels.