A Book: Nuclear Energy – Peaceful Ways to Serve Humanity.

In 2024, nuclear power plants generated approximately 2602 terawatt-hours (TWh) of electricity, representing about 9 percent of the world’s total electricity production. The United States was the largest producer iof nuclear power, followed by China and France.  While the US has the most operating reactors, France leads in the percentage of its electricity derived from nuclear power (Energy Shift). 

Canada primarily manufactures CANDU (CANADA DEUTERIUM URANIUM) reactors, a type of pressurized heavy-water reactor known for using natural uranium fuel and heavy water as a moderator. These reactors are a key part of Canada’s energy infrastructure. 

Canada has exported 12 CANDU reactors to six countries. These countries include South Korea (4 reactors), China (2 reactors), India (2 reactors), Romania (2 reactors), Argentina (1 reactor), and Pakistan (1 reactor). In addition to the reactors themselves, Canada has also sold the engineering expertise needed to build and operate them.

Canada has a comprehensive nuclear safety regulatory framework covering facilities and activities. Its 19 operating nuclear power reactors – situated at four sites – generate about 13 per cent of Canada’s electricity. Canada also has uranium mines and mills, processing and fuel fabrication facilities, and waste storage sites. Canada also uses radiation sources in medical, industrial, scientific, and research applications, and has five research reactors.

The nuclear sites in Canada include  3 in Ontario at Bruce, Pickering, and Darlington and 1 in New Brunswick at Point Lepreau. 

Nuclear power is a low-carbon source of energy, because unlike coal, oil or gas power plants, nuclear power plants practically do not produce Carbon Dioxide (CO₂) during their operation. Nuclear reactors generate close to one-third of the world’s carbon free electricity and are crucial in meeting climate change goals.

Nuclear energy is a form of energy released from the nucleus of atoms through two main processes:

1. Nuclear Fission:

• This is the process used in current nuclear power plants;
• It involves splitting heavy atomic nuclei (usually uranium-235 or plutonium-239) into smaller parts;
• The process releases a large amount of energy in the form of heat; and
• This heat is used to produce steam, which drives turbines to generate electricity.

2. Nuclear Fusion:

• Fusion involves combining light nuclei (like hydrogen isotopes) to form a heavier nucleus;
• It releases even more energy than fission; and
• It’s the process that powers the sun, but controlled fusion for power generation is still under research and not yet commercially viable.

The history of nuclear energy spans from the initial discovery of atomic radiation to the development of nuclear power plants for electricity generation. Early research focused on understanding atomic structure and radioactivity, leading to the discovery of nuclear fission and the potential for vast energy release. This knowledge was initially applied to develop atomic bombs, but soon after, efforts shifted towards harnessing nuclear energy for peaceful purposes, including power generation. 

Here’s a more detailed timeline:

• Early 1900s: Scientists like Henri Becquerel, Marie Curie, and Ernest Rutherford made ground-breaking discoveries about radioactivity and atomic structure; 
• 1930s: Enrico Fermi’s experiments with neutron bombardment of uranium suggested the possibility of nuclear fission;
• 1939: Nuclear fission was formally discovered, and scientists realized its potential for releasing large amounts of energy; 
• 1940s: World War II spurred the development of the atomic bomb, with the Manhattan Project leading to the creation of the first nuclear weapons; 
• Late 1940s – 1950s: Following the war, attention turned to the peaceful applications of nuclear energy, including nuclear-powered submarines and the first nuclear power plants;
• 1951: The Experimental Breeder Reactor I (EBR-I) in the US produced the first electricity from a nuclear reactor;
• 1954: The Obninsk Nuclear Power Plant in the Soviet Union became the first to connect to a power grid; 
• 1950s-1970s: Nuclear power plants saw rapid global expansion, particularly in countries like the US, France, and the UK. 
• 1970s-1980s: Concerns about nuclear safety and accidents, such as the Three Mile Island accident in 1979 and the Chernobyl disaster in 1986, led to increased regulation and public opposition; and
• Present: Nuclear power remains a significant source of electricity in many countries, but faces challenges related to safety, waste disposal, and public perception. 

Following fast growth during the 1970s to 1990s, global generation has slowed significantly. In fact, we see a sharp dip in nuclear output following the Fukushima tsunami in Japan in 2011, as countries took plants offline due to safety concerns.

But we also see that production has once again increased in recent years.  Here’s a graph to illustrate it:

The global trend in nuclear energy generation masks the large differences in its role at the country level.  Some countries get no energy from nuclear — or aim to eliminate it completely — while others get most of their power from it.  The following chart shows the amount of nuclear energy generated by country. France, the USA, China, Russia, and South Korea all produce relatively large amounts of nuclear power:

Since transport and heating tend to be harder to decarbonize – they are more reliant on oil and gas – nuclear and renewables tend to have a higher share in the electricity mix versus the total energy mix.

This chart shows the share of electricity that comes from nuclear sources.

Globally, around 10 percent of our electricity comes from nuclear power. However, some countries, such as Belgium, France, and Ukraine, rely heavily on it.  Here’s an image to illustrate it:

When the commercial nuclear industry began in the 1960s, there were clear boundaries between the industries of the East and West. Today, the nuclear industry is characterized by international commerce. A reactor under construction in Asia today may have components supplied from South Korea, Canada, Japan, France, Germany, Russia, and other countries. Similarly, uranium from Australia or Namibia may end up in a reactor in the UAE, having been converted in France, enriched in the Netherlands, de-converted in the UK and fabricated in South Korea.

According to World Nuclear Association:

There are about 440 commercial nuclear power reactors operable in about 30 countries, with about 390 GWe of total capacity. About 60 more reactors are under construction. Over 50 countries operate a total of about 220 research reactors and a further 180 nuclear reactors power around 140 ships and submarines.

France gets around 70 PERCENT of its electricity from nuclear energy, while Ukraine, Slovakia, Belgium and Hungary get about half from nuclear. Japan was used to relying on nuclear power for more than one-quarter of its electricity and is expected to return to somewhere near that level.

NUCLEAR ELECTRICITY GENERATION BY COUNTRY 2021

Source: IAEA Pris

The performance of nuclear reactors has improved substantially over time. Over the last 40 years the proportion of reactors reaching high capacity factors has increased significantly. For example, 68 percent of reactors achieved a capacity factor higher than 80 percent in 2021, compared to less than 30 percent in the 1970s, whereas only 6 percent of reactors had a capacity factor lower than 50 percent in 2021, compared to just over 20 percent in the 1970s.

LONG-TERM TRENDS IN CAPACITY FACTORS

Source: World Nuclear Association, IAEA Pris

The reality is that each method opted to generate electricity, generates Greenhouse Gases (GHGs) in varying quantities throughout the life cycle – construction, operation, and decommissioning.  Some generation methods such as coal fired power plants release the majority of GHGs when their carbon-containing fossil fuels are burnt, producing carbon dioxide (CO2). Others, such as wind power and nuclear power, give rise to much less emissions, these being during construction and decommissioning, or mining and fuel preparation in the case of nuclear.  Comparing the lifecycle emissions of electrical generation allows for a fair comparison of the different generation methods on a per kilowatt-hour basis. The lower the value, the fewer GHG emissions are released.

Here is an important consideration.  Nuclear power plants produce no GHG emissions during operation, and over the course of its life-cycle, nuclear produces about the same amount of carbon dioxide-equivalent emissions per unit of electricity as wind, and one-third of the emissions per unit of electricity when compared with solar.

Average life-cycle carbon dioxide-equivalent emissions for different electricity generators (Source: IPCC)

Perhaps another important factor about the generation of nuclear electricity is the cost.  Here is a graph designed to illustrate the breakdown of Operating Costs associated with Coal, Gas, and Gas Generation:

It should be kept in mind that nuclear technology is not just used to supply electricity to the grid; it is in a wide variety of other uses such as medicine, heating and space travel.  For instance:

• Nuclear Medicine:  Nuclear medicine uses radiation to allow doctors to make a quick, accurate diagnosis of the functioning of person’s specific organs, or to treat them. Radiotherapy can be used to treat some medical conditions, especially cancer, using radiation to weaken or destroy particular targeted cells.
  • Tens of millions of patients are treated with nuclear medicine each year;
  • Over 10,000 hospitals worldwide use radioisotopes in medicine, and about     90  percent of the procedures are for diagnosis.  The most common radioisotope used in diagnosis is technetium-99, with some 30 million procedures per year, accounting for 80 percent of all nuclear medicine procedures worldwide; and
  • Modern industry also uses radioisotopes in a variety of ways. Sealed radioactive   sources are used in industrial radiography, gauging applications and mineral analysis.
• Heat for Desalination: Heat from nuclear reactors can be used directly, instead or as well as being used to generate electricity. This heat can be used for district heating, as process heat for industry or for desalination plants, used to make clean drinkable water from seawater; and
• Space Missions:  Radioisotope thermal generators are used in space missions. The heat generated by the decay of a radioactive source, often Plutonium-238, is used to generate electricity.  The Voyager space probes, the Cassini mission to Saturn, the Galileo mission to Jupiter and the New Horizons mission to Pluto all are powered by RTGs. The Spirit and Opportunity Mars rovers have used a mix of solar panels for electricity and RTGs for heat. The latest Mars rover, Curiosity, is much bigger and uses RTGs for heat and electricity as solar panels would not be able to supply enough electricity.

In the future, electricity or heat from nuclear power plants could be used to make hydrogen. Hydrogen can be used in fuel cells to power cars, or can be burnt to provide heat in place of gas, without producing emissions that would cause climate change.

There is a clear need for new generating capacity around the world, both to replace old fossil fuel units, especially coal-fired ones, which emit large amounts of carbon dioxide, and to meet increased demand for electricity in many countries. In 2021, 61 percent of electricity was generated from the burning of fossil fuels. Despite the strong support for, and growth in, intermittent renewable electricity sources in recent years, the fossil fuel contribution to power generation has not changed significantly in the last 15 years or so (66.5 percent in 2005).

Updated on 15 June 2025.

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