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Innovations in Nuclear Technologies

Medical image of the brain using Technetium-99m

Medical image of the brain using Technetium-99m (wenht, iStockphoto)

Learn about why Canada is a world leader in nuclear technology.

You may not know that Canada is a world leader in nuclear technology. It has been for decades. Canadians developed the CANDU reactor system that provides electricity to many Canadian homes. Canadians also supply the world with radioisotopes for cancer therapy and medical diagnosis. 

Did you know?

CANDU stands for Canada deuterium uranium.

Every day, Canadian scientists and engineers develop cutting-edge uses of nuclear energy. This article is about two of them.

Small Modular Reactors

Canadians use nuclear reactors for a variety of purposes. They are best known for generating electricity. But nuclear reactors are also used in researchmaterials testing and medicine.

CANDU reactors are large devices located at nuclear generating stations. There are 4 nuclear generating stations in Canada. Together they provide about 15% of Canada's electricity. Electricity generation from nuclear energy does not emit greenhouse gases.

Canada’s Nuclear Generating Stations



Total capacity (MW)

Number of reactors

Start of Operation



3 512





6 610





3 244



Point Lepreau

New Brunswick




Aerial view of Bruce Nuclear generating station
Bruce Nuclear Generating Station near Kincardine, Ontario (Source: CNSC).

Did you know?

Bruce Power is one of the largest operating nuclear generating stations in the world.

Large nuclear generating stations supply electricity to millions of people. But they cannot be built just anywhere. They need to be near where people are. That is why three of the four nuclear stations are in southern Ontario. They also need to be near large bodies of water. They use the water for cooling the reactors. That is why the nuclear stations are near large lakes or the ocean. Even if a location is suitable, a large nuclear reactor might not be a practical option. Large reactors cost billions of dollars and take years to build. This does not make large reactors practical in many parts of Canada.

But what if reactors did not have to be big? Thinking small has led to the development of a new type of reactor, the small modular reactor (SMR). And Canada is taking a leading role.

What is a Small Modular Reactor? by the Canadian Nuclear Safety Commission (2020) (0:47 min.).

Small Modular reactors are:

  • Small – in both power and size;
  • Modular – meaning they’re pre-made in a factory and shipped to where they’re needed; and
  • Reactors – meaning they use nuclear fission to produce energy.

As their name suggests, SMRs are smaller than normal nuclear reactors. A typical CANDU reactor generates about 700 MWe. Using new reactor technologies, SMRs can generate anywhere from 10 MWe to 300 MWe, This smaller size means they can be used in more places and in new ways.

In Canada, SMRs could be useful for:

  • Provinces that are getting rid of fossil fuel generating stations.
  • Provinces with small electrical grids, such as Saskatchewan.
  • Remote communities with no electrical grids. Many of these communities currently rely on diesel fuel and renewables.
  • Heavy industries. This could provide industries, such as oil and mining, with reliable and clean energy.

Canada is still in the early stages of SMR development. To learn more about what's next, check out Canada's Small Modular Reactor (SMR) Action Plan

Canada's Small Modular Reactor Action Plan by Natural Resources Canada (2021) (1:28 min.).

New Sources of Medical Isotopes

A second area of focus in nuclear technology is making medical isotopes. Isotopes are atoms that have the same number of protons but a different number of neutrons. Some isotopes of elements are unstable. Unstable isotopes, or radioisotopes, emit radiation as they break down and become more stable. Radioisotopes can be used to diagnose or treat diseases like cancer.

Did you know?

The National Research Experiment (NRX) reactor in Chalk River, Ontario began producing radioisotopes in 1947.

Since 1971, the Pickering Generating Station has produced the radioisotope Cobalt-60 (Co-60). Reactors at Bruce Power and the Darlington Nuclear Generating Station also produce Co-60. This is one of the world’s most valuable medical isotopes. Co-60 is an isotope that emits gamma radiation. It is used to sterilize 40 percent of the world's medical devices. It is also used for radiation therapy to treat complex forms of cancer, including brain tumors.

Did you know?

Approximately 50 per cent of the world’s Cobalt-60 is produced in Ontario.

Another important medical isotope produced in Canada is molybdenum-99 (Mo-99). Mo-99 breaks down to become Technetium-99 (Tc-99m). Over 80% of diagnostic scans in the world use Tc-99m. This makes it the one of the world's most used radioisotopes.

From 1970 to 2016, Mo-99 was produced at the National Research Universal (NRU) reactor at Chalk River. After decisions were made not to upgrade the reactor, it was shut down in 2018. The loss of this research reactor left a large gap in Mo-99 production.

Staff celebrating the 60th anniversary of the NRU in 2017
Staff celebrating the 60th anniversary of the NRU in 2017 (Source: Government of Canada). Did you know?

Did you know?

At its peak, the NRU produced 40% of the world’s medical isotopes.

In response, the Canadian Nuclear Isotope Council and the Institute for Advanced Medical Isotopes (IAMI) were founded. These organizations support Canadian leadership and innovation in medical isotopes. The IAMI will operate out of TRIUMF in British Columbia. TRIUMF is home to the world's largest cyclotron. A cyclotron is a type of particle accelerator. At TRIUMF they are using the cyclotron, rather than a nuclear reactor, to produce Tc-99m.

Commercial reactors are also stepping up to fill the gap. The Darlington Nuclear Generating Station will be the first large-scale commercial power plant in the world to produce Mo-99.

Did you know?

The Canadian Nuclear Safety Commission (CNSC) regulates all activities associated with nuclear energy in Canada.

In Conclusion

Nuclear technology continues to play an important role solving our world's problems. Canada's nuclear industry is at the forefront of these efforts to provide clean, safe electricity from nuclear reactors and life-saving medical isotopes.

Let’s Talk Science appreciates the work and contributions of the Canadian Nuclear Safety Commission in the development of this Backgrounder.

Government of Canada logo
Government of Canada logo

The Canadian Nuclear Safety Commission regulates the use of nuclear energy and materials to protect health, safety, security and the environment; to implement Canada’s international commitments on the peaceful use of nuclear energy; and to disseminate objective scientific, technical and regulatory information to the public.


Small Modular Reactors 

More information about small modular reactor technology from Canadian Nuclear Laboratories.

Isotopes and Medical Innovation

Learn about Bruce Power’s role in producing medical isotopes.

Why Medical Isotopes Matter (2020)

This video (3:55 min.) from Bruce Power talks about the importance of medical isotopes.


Atomic Energy of Canada Ltd. (n.d.). Medical Isotopes. Science & Technology.

Atomic Energy of Canada Ltd. (n.d.). Small Modular Reactors. Science & Technology.

Bruce Power. (n.d.). Isotopes and Medical Innovation. Our projects and innovation.

Canadian Nuclear Association. (2020, Dec. 18). CNA Welcomes Small Modular Reactor Action Plan

Canadian Nuclear Association. (n.d.). How a nuclear reactor works.

Canadian Nuclear Association. (n.d.). Small Modular Reactors (SMRs).

Canadian Nuclear Isotope Council. (n.d.). Canadian Isotope Landscape.

Canadian Nuclear Laboratories. (n.d.). Small Modular Reactor Technology.

Canadian Nuclear Safety Commission. (2020). Small Modular Reactors. Reactors.

Natural Resources Canada. (2020). Uranium and nuclear power facts. Energy Facts.

Ontario Power Generation. (n.d.). The unseen wonders of nuclear power. Medical Isotopes.

World Nuclear Association. (May 2020). Radioisotopes in Medicine.

World Nuclear News. (2020, Sept. 25). Canadian firms make progress with radioisotope production.