Overview of the Integrated System Model (ISM)

Abstract

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. Currently, two potential host siting areas, the Wabigoon Lake Ojibway Nation – Ignace area (also referred to as the Revell Site) and the Saugeen Ojibway Nation – South Bruce area (also referred to as the South Bruce Site), remain in the site selection process.

A component of the site selection process is an assessment of the safety of a potential repository. 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.

The post-closure safety analysis is a component of the overall safety assessment and considers the long-term performance of the repository and assesses potential radiological and non-radiological impacts to people and the environment.

This paper provides an overview of the components and capabilities of the Integrated System Model (ISM), the primary post-closure safety assessment tool developed by the NWMO to assess radiological and non-radiological impacts of a repository. The ISM is currently being used in the site- specific post-closure safety analysis of the Revell and South Bruce sites in support of the site-selection process.