One of the guiding principles of the Nuclear Waste Management Organization’s (NWMO) work is the protection of water. 

The deep geological repository for Canada’s used nuclear fuel will be located at the Revell Batholith, a rock formation in northwestern Ontario, on the territory of Wabigoon Lake Ojibway Nation near the Township of Ignace. It will be located more than 500 metres underground. To understand the nature of water at those depths, we used our six one-kilometre deep boreholes to test and gather water samples.

Dr. Alexander Blyth is a hydrogeologist and Manager of Geoscience Research and Development at the NWMO. He has been studying the water at the repository site for several years.

“We have completed approximately 6,000 metres of borehole drilling, and we were only able to gather water samples seven times during drilling. Most of those samples were from above 150 metres in depth, with only two samples taken below that depth. That shows how little water there is in the rock at the Revell site,” Blyth said.

Dating the water from depth is important, since it will help show how long that water has been isolated from the surface water. This information is being collected using a number of different techniques, including looking for tritium — which would indicate water that had been in contact with the surface within the past 60 years — and other tests that can trace the water back thousands or even millions of years such as carbon 14 dating and noble gas testing.

“Our preliminary analysis has shown that our water samples from below 150 metres are of ancient water several millions of years old,” Blyth said. “This means that it has been several millions of years since that water has connected with the surface, which shows the tightness and isolation of the water in this rock.”

The Canadian Shield is known to be one of the oldest, most stable areas on the planet, and our ongoing testing has confirmed the strength and quality of this rock in the Revell Batholith. The quality of the rock and the demonstrated scarcity of water at depth are just two of the many favourable factors that indicate this location is well-suited for the safe, long-term containment and isolation of Canada’s used nuclear fuel in a deep geological repository.

The NWMO understands the importance of water and the need to protect it for generations to come. Protecting water is a shared commitment with Canadians and Indigenous Peoples, and a key consideration in the federal review process.