What is nuclear energy?

The common definition for nuclear energy is the energy released by a chain reaction, especially by fission or fusion. Practically speaking, nuclear energy uses fuel made from mined and processed uranium to make steam and generate electricity.

Nuclear generation is the only source of electricity that can produce a constant supply of power – known as baseload power—reliably without emitting greenhouse gases.

Nuclear energy has one of the lowest environmental impacts on land and natural resources of any electricity source.

How does it work?

A nuclear reactor produces electricity in much the same way other power plants do. The chain reaction produces the energy, which turns water into steam. The pressure of the steam turns a generator, which produces electricity.

The difference is in how the heat is created. Power plants that run on fossil fuels burn coal, oil or natural gas to generate heat. In a nuclear energy plant, heat is produced from splitting atoms – a process called nuclear fission.

  • Nuclear reactor creates heat that is used to make steam
  • The steam turns a turbine connected to an electromagnet, called a generator
  • The generator produces electricity

In a Pressurized Water Reactor (PWR) – the type of reactor being built in the UAE – high pressure prevents water in the reactor vessel from boiling. The super-heated water is carried to a steam generator, which is made up of many small pipes. The heat in these pipes is used to turn a second, isolated, supply of water to steam, which is in turn used to drive the turbine. The water from the reactor is pumped back into the reactor vessel and reheated. The steam from the turbine is cooled in a condenser and the resulting water is sent back to the steam generator.


Enriched uranium is the fuel for nuclear reactors. Uranium is an abundant, naturally radioactive element found in most rocks. As uranium breaks down or decays, it produces heat inside the Earth’s crust. A similar process generates heat inside a nuclear reactor.

Nuclear Fission

Fission is the process of splitting a nucleus in two.

Inside each uranium fuel pellet, there are millions of uranium nuclei. When these nuclei are split, a huge amount of energy is released. Some of this energy is from radiation, but the biggest source is kinetic energy. This is the energy that produces heat inside a reactor, which in turn is used to generate steam, and ultimately creates electricity.


Worldwide facts

For more than 50 years, nuclear energy has provided the world with reliable electricity.  Today, more than 400 plants are operating in more than 25 countries. 

These plants generate around 14 percent of the world’s electricity without emitting greenhouse gases.

More nations are exploring the use of nuclear energy, particularly as electricity demand increases and concerns about climate change rise.

Here is a snapshot of the global nuclear energy industry:

  • 30 countries worldwide are operating more than 400 nuclear reactors for electricity generation
  • 67 new nuclear plants are under construction in 15 countries
  • Nuclear energy plants provided 10.9 percent of the world's electricity production in 2012
  • In 2014, 13 countries relied on nuclear energy to supply at least one-quarter of their total electricity.
  • On average, the world’s nuclear power plants offset approximately 2.5 billion metric tons of carbon dioxide annually, approximately double the target set by the Kyoto Agreement.
  • The World Association of Nuclear Operators (WANO), an organization dedicated to safe and reliable operation of nuclear energy plants, conducts independent peer reviews for each of the world’s commercial nuclear power plants in operation. 

For more information, visit the following online resources:

International Atomic Energy Agency

World Nuclear Association (WNA)

World Association of Nuclear Operators

Nuclear Energy Institute (NEI)

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