Canada’s Nuclear Waste Management Organisation (NWMO) has published new research – the 2023 Confidence in Safety reports – on the two potential sites under consideration to host a deep geological repository (DGR) for used nuclear fuel. NWMO says the reports reinforce confidence in safety of both sites, building on the previous 2022 Confidence in Safety reports. They support the conclusion that the NWMO is confident a DGR can be constructed at either site to safely and responsibly manage Canada’s used nuclear fuel for the long term.

NWMO President & CEO Laurie Swami said the reports underscore that either of the sites can safely host the project. “Safety is at the core of everything we do. It has driven our project design, engineering, environmental research and community engagement. These reports are the culmination of years of meticulous study by our science and engineering teams, and they represent a major milestone as we prepare to select a site later this year."

The proposed DGR will be constructed roughly 650-800 metres below ground level and encased in a natural shield of solid rock. The repository design incorporates a series of engineered barriers to ensure the fuel can be isolated safely for many thousands of years.

The site selection process began in 2010 when 22 communities expressed interest exploring their potential to host the GDR. Following years of technical assessment and community engagement, two potential sites remain in the process: one in the Wabigoon Lake Ojibway Nation-Ignace area in northwestern Ontario and the other in the Saugeen Ojibway Nation-South Bruce area in southern Ontario.

Both potential sites are situated in stable, seismically quiet settings with rock formations of the necessary depth, breadth and volume to host the repository. In addition, the studies found no economically viable resources within the rock, such as minerals, salt or gas, reducing the possibility of human intrusion in the future.

The updated Confidence in Safety reports provide a comprehensive summary of the NWMO’s understanding of each potential siting area based on years of research. The reports highlight the strength of geological features in each location, which ensure the site can safely contain and isolate used nuclear fuel. They also include initial site-specific safety assessment results and additional research on the geology and engineering for both potential sites.

“The NWMO has been conducting studies at these sites for several years now, which have gotten progressively more detailed,” said Dr Paul Gierszewski, lead author of the reports. “Within these reports, we have been able to complete additional studies to understand important factors like the characteristics of the geology, long-term stability of the rock, seismic setting, and the strength of the multiple-barrier system. Our findings have reinforced our conclusion from 2022 that a deep geological repository can safely be constructed at either site.”

The reports will be used to support continuing dialogue with Canadians and Indigenous peoples about the project. They will also help inform the potential host communities as they make their willingness decisions in the lead-up to a site being selected later this year.

Once a site is chosen with informed and willing hosts, additional technical studies will be conducted to provide more precise information for the repository design and formal safety case, which will be submitted to regulators. The safety of a proposed site will also be confirmed through a rigorous regulatory review of the repository design and safety case, including through the federal Impact Assessment Act process and licensing by the Canadian Nuclear Safety Commission. The regulatory and licensing process is expected to take approximately 10 years to complete.

Image courtesy of NWMO