06/23/2026
Not nearly enough people know about Canada's long history pioneering nuclear technology.
ZEEP was tiny by power-plant standards, but historically it was enormous.
On September 5, 1945, the Zero Energy Experimental Pile went critical at Chalk River, making Canada home to the first operating nuclear reactor outside the United States.
That mattered because ZEEP proved Canada could work with heavy water and natural uranium, the same basic logic that later shaped the CANDU reactor family.
Chalk River became one of the places where Canada quietly built a nuclear identity, with research reactors, medical isotope work, and engineering knowledge that travelled far beyond Ontario.
There’s a very Canadian pattern here.
Start with a modest research project in the woods beside the Ottawa River, then somehow end up influencing power grids, hospitals, and reactor designs around the world.
(Source: Canadian Nuclear Laboratories, Canadian Nuclear Safety Commission, Canada Science and Technology Museum)