Atoms make up everything in the universe, and in their core they have a large amount of energy that contains a lot of power, holding the nucleus together. This energy is called nuclear energy. There are two methods of atomic reactions that can release nuclear energy in order to create electricity. Nuclear fusion, where atoms are joined together, and nuclear fission where atoms a separated. The latter method is currently being used in nuclear reactors to create electricity.
The process begins with pellets of the element uranium that are used to fuel the fission. The atoms of uranium are split apart producing fission products. These small products cause more atoms or uranium to split apart which causes a chain reaction that produces energy, and therefore heat. The heat warms a cooling agent, which is most commonly water, and when the cooling agent is warm enough to produce steam, the steam is then used to turn turbines which drive generators and finally create electricity. This nuclear energy provides clean power with no greenhouse gas emissions. However, the side effect of this reaction is the production of extremely toxic radioactive waste such as uranium pellets. This waste can remain radioactive for what could be thousands of years. Therefore the government requires certain rules and regulations for the disposal process in order to avoid radioactive contaminations.