Proposed Ontario site would store spent fuel up to 800 metres below ground
Canada’s Nuclear Waste Management Organization (NWMO) has published the initial project description for the country’s proposed deep geological repository for spent nuclear fuel, marking the beginning of an in-depth regulatory process and a milestone for NWMO’s work as the project moves from planning to independent review.
The NWMO said the step also brings another opportunity for host communities, potentially impacted Indigenous groups and the public to share their perspectives and contribute to shaping Canada’s plan to safely contain and isolate used nuclear fuel over the long term.
In November 2024, Wabigoon Lake Ojibway Nation (WLON) and the Township of Ignace agreed to enter the regulatory decision-making phase as potential host communities for the repository.
Now, with the submission of the initial project description, the project is advancing to the next step. This document details the deep geological repository’s purpose, need and expected benefits, and it explains how the project will be implemented in a manner that protects people and the environment. It also provides a preliminary assessment of potential impacts and describes measures to avoid or mitigate them.
The proposed project site would be 21 km southeast of the WLON and 43 km northwest of the Town of Ignace in Ontario. It would provide permanent storage for some 5.9 million bundles of used nuclear fuel between 650 and 800 metres below ground and have an underground footprint of about 2 km by 3 km.
The project is expected to span around 160 years, encompassing site preparation, construction – which is projected to take about 10 years – operation from the 2040s and decades of post-operations closure monitoring.
The only deep geological repository close to operation is in Finland, where the first stage of a trial run was completed in September 2024. Other nuclear nations including France, the UK and Sweden are also advancing plans for their own long-term storage sites.
Background: How The Repository Will Work
Most used nuclear fuel in Canada comes from Candu reactors and is a stable solid, sealed into a specially designed container and bound into a bundle. It is currently stored in temporary, onsite facilities at reactor locations and at research sites.
Each bundle weighs about 24 kg and is roughly the size of a fireplace log. It takes hundreds of thousands of years for the radioactivity of the used nuclear fuel to return to the level of natural uranium, which is why Canada needs a safe, long-term approach for storage.
The repository would be built around 650-800 metres underground, well below any ground water, surrounded by crystalline rock and granite and far from any valuable natural resource deposits that future generations may one day want to extract.
The plan calls for used nuclear fuel to be stored in a network of tunnels and placement rooms.
A series of engineered and natural barriers will work together to safely contain and isolate used nuclear fuel within the repository. Each barrier will provide a unique and stand-alone level of protection, while also serving as a backstop for the previous barrier. If any of these barriers were to fail, another would be there to ensure any dangerous materials remained contained and isolated.
Surveying work for a potential repository being carried out in the Wabigoon Lake Ojibway Nation in Ontario. Courtesy NWMO.
