page_title: Nuclear power in Canada
section_title: Experimental reactors
hierarchical_section_title: Nuclear power in Canada / History / Experimental reactors
caption_attribution_description: English: ZEEP reactor in February 1954 with NRX and NRU (under construction, in background)
context_page_description: Nuclear power in Canada is provided by 19 commercial reactors with a net capacity of 13.5 Gigawatts, producing a total of 95.6 Terawatt-hours of electricity, which accounted for 16.6% of the country's total electric energy generation in 2015. All but one of these reactors are located in Ontario, where they produced 61% of that province's electricity in 2019. Seven smaller reactors are used for research and to produce radiopharmaceuticals for use in nuclear medicine.
  Canadian nuclear reactors are a type of pressurized heavy-water reactor of indigenous design, the CANDU reactor. CANDU reactors have been exported to India, Pakistan, Argentina, South Korea, Romania, and China.
context_section_description: In 1944, approval was given to proceed with the construction of the smaller ZEEP (Zero Energy Experimental Pile) test reactor at Chalk River, Ontario and on September 5, 1945 at 3:45 p.m., the 10-watt ZEEP achieved the first self-sustained nuclear reaction outside the United States.
  In 1946, the Montreal Laboratory was closed, and the work continued at the Chalk River Nuclear Laboratories. Building partly on the experimental data obtained from ZEEP, the National Research Experimental (NRX)—a natural uranium, heavy water moderated research reactor—started up on July 22, 1947. It operated for 43 years, producing radioisotopes, undertaking fuels and materials development work for CANDU reactors, and providing neutrons for physics experiments. It was eventually joined in 1957 by the larger 200 megawatt (MW) National Research Universal reactor (NRU).
  From 1967 to 1970, Canada also developed an experimental miniature nuclear reactor named SLOWPOKE (acronym for Safe LOW-POwer Kritical Experiment). The first prototype was assembled at Chalk River and many SLOWPOKEs were built, mainly for research. Two SLOWPOKEs are still in use in Canada and one in Kingston, Jamaica; one has been running at École Polytechnique de Montréal since 1976, for instance.
caption: ZEEP (left), NRX (right) and NRU (back) reactors at Chalk River, 1954.
exif: {}