The Nuclear Waste Management Organization (NWMO) has officially started the process of selecting a site for a second deep geological repository for intermediate- and high-level radioactive waste.

Through a discussion document, the organization is inviting feedback from Canadians and Indigenous Peoples to help refine the site selection process.

Canada’s intermediate- and high-level waste is safely stored on an interim basis, but the methods used today are temporary and not suitable for the very long term.

“Like many countries with commercial nuclear power programs, Canada is planning for the future,” said Laurie Swami, President and CEO of the NWMO. “There is international scientific consensus that a deep geological repository is the safest way to manage intermediate- and high-level waste over the long-term.”

In 2024, after a comprehensive site selection process, NWMO selected a site in northwestern Ontario as the future location to build a deep geological repository to store Canada’s used nuclear fuel. That proposed site will soon begin a multi-year regulatory decision-making process to independently confirm its safety before the project can proceed.

For the new project, the organization says it will continue to focus on technical safety and community willingness as primary site selection criteria. It is inviting public input to further refine its proposed approach before beginning the site selection process for this second repository, in 2028.

The second repository will house intermediate- and non-fuel high-level waste and potentially also used nuclear fuel from new nuclear reactors built in Canada in the future.

Intermediate-level waste includes equipment and components that have been used inside nuclear reactors in the production of electricity from nuclear fuel, but excludes nuclear fuel itself, which is high-level waste.

Non-fuel high-level nuclear waste may include, for example, small quantities of materials used in the process of making medical isotopes.