The nuclear power stations are industrial facilities where electrical energy is generated from the transformation of nuclear energy. To achieve this goal, fissionable material is used as raw material by means of nuclear reactions that generate an enormous amount of heat. This heat evaporates water to generate steam, which is used to drive the turbines that drive the industrial alternators that generate electricity.
In this type of power plant, there are usually more than two reactors. These reactors consist of containers or industrial vessels covered with insulating material that hold the raw material (Uranium-235 or Plutonium-239).
The nuclear power stations offer an enormous amount of energy with relatively little raw material and are an alternative to generating systems that use oil or petroleum derivatives. However, they pose a high risk to health and the environment, which is why safety and material handling measures have been improved in recent years.
Here is a video where you can see clearly and simply how nuclear power plants work: