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All power plants are based on the same idea: produce heat, heat turns water into steam, steam goes on to create electricity. To produce that initial heat, a nuclear plant splits atoms instead of burning fossil fuels. Want details? You've come to the right place.​
When one atom splits into two, it releases energy.

Other types of power plants burn coal or oil to make heat that starts the process. Nuclear plants split atoms. It’s called “fission.”

When the atoms split apart, energy is released in the form of heat. The heat boils water and creates steam. The steam then turns a turbine. As the turbine spins, the generator turns and its magnetic field produces electricity. The electricity is then put on the grid, where it’s available to power homes and businesses.

A chain reaction creates a steady flow of energy.

During fission, a neutron splits an atom's nucleus, which releases energy – and additional neutrons. These ejected neutrons can split other nuclei, releasing other neutrons to split still other nuclei. It’s a chain reaction. It’s self-sustaining. Under focused, careful control in a nuclear energy plant, the chain reaction produces a stable energy stream.

There are two different types of reactors.

Pressurized Water Reactor

Exelon has eight Pressurized Water Reactor (PWR) plants and 14 Boiling Water Reactor (BWR) plants.


In a PWR, the reactor vessel heats water but does not boil it. The pressurized hot water exchanges heat with a water system in a separate pipe. This water turns to steam and then drives the turbine.

Boiling Water Reactor


In a Boiling Water Reactor (BWR), the reactor vessel heats water, creates steam and that steam then drives a turbine. This is the second most common type of electricity-generating nuclear reactor after the pressurized water reactor.

Our fuel is extracted from rock all over the world.

Uranium is a naturally occurring element in the Earth's crust. It’s also a naturally "fissile" material. Bombard uranium atoms with tiny particles called neutrons, fission occurs – and powerful energy is released.

  • Uranium is mined, brought to the surface and sealed in drums.
  • The uranium is then concentrated and made useful by spinning rapidly in centrifuges.
  • This enriched uranium is then converted to powder, pressed into small fuel pellets and heated so the pellets harden.

One small uranium fuel pellet – think of the tip of an adult’s pinky finger – produces the same amount of energy as:

  • A ton of coal (that’s right, a ton)
  • 3 barrels of oil (they’re 42 gallons each)
  • 17,000 cubic feet of natural gas