Defining Human Receptors for Assessing Safety of Canada’s Deep Geological Repository for Used Nuclear Fuel
Chantal Medri | Nuclear Waste Management OrganizationEnoch ABC Ballroom
The Nuclear Waste Management Organization (NWMO) is responsible for the implementation of Adaptive Phased Management. Under this plan, used nuclear fuel will ultimately be placed within a deep geological repository in a suitable host rock formation. The NWMO is currently in the siting process, working towards site selection at the end of 2024. Two areas remain in the site selection process: the Wabigoon Lake Ojibway Nation-Ignace area in north-western Ontario and the Saugeen Ojibway Nation-South Bruce area in southern Ontario. The NWMO has been developing preliminary post-closure safety analysis to support site selection.
A primary endpoint of a safety analysis is an estimate of potential doses that someone living in the area — a receptor — could receive in various scenarios. To measure repository performance and demonstrate safety, hypothetical doses for the receptors during that facility’s operation (pre-closure) and after closure (post-closure) are compared to set dose benchmarks. The dose received largely depends on a person’s lifestyle, specifically, their relationship with their environment. The NWMO’s site-specific safety analyses consider two different types of lifestyles: a most-exposed group and illustrative local lifestyles. The most-exposed group is a receptor designed to maximise potential dose and demonstrate that present regulatory limits would be met, independent of the potential landscape and social evolutions. The illustrative local lifestyles demonstrate repository’s safety as it relates to local communities’ current and past practices. Illustrative local lifestyles include various Indigenous, town resident, and rural lifestyles. This presentation describes the methodology for defining receptors during the pre-closure and post-closure phases, giving examples of receptors currently selected for safety analyses, the characteristics of each lifestyle, and exposure pathways relevant to each lifestyle.