NUCLEAR ENERGY

Nuclear energy is that form of energy that is released when the nuclei of atoms split or fuse together.
The nuclear reaction whereby energy is obtained by splitting is called 'fission', while the one where the nuclei come together is called 'fusion'.
In nuclear fission, the nuclei of heavy chemical elements, e.g. uranium or plutonium, are bombarded by neutrons and, having become unstable nuclei, split into lighter chemical elements, e.g. krypton and barium, releasing further neutrons that set off a chain reaction.
The nuclear fission reaction is the one that typically takes place in conventional nuclear power plants. This type of reaction entails many risks, because both the elements to be split and the lighter elements produced are very radioactive and, therefore, can seriously pollute the environment, even damaging the health of people and other living beings.
In nuclear fusion, the nuclei of light chemical elements, such as, for example, hydrogen, are brought so close together that they fuse into the nucleus of heavier atoms, such as, for example, helium.
The techniques used to achieve nuclear fusion mostly consist of raising the temperature of the original chemical elements by about a hundred million degrees in order to achieve very high-speed collisions between the atoms involved in the reaction. These collisions are so violent that they not only bring the nuclei closer together, but also cause them to fuse into a heavier nucleus.
Nuclear fusion reactions are still being studied today. Light atoms can be made to fuse together using technologies that exploit magnetic fields or lasers. However, these techniques are, in fact, still at an experimental stage and, to date, cannot be exploited to any real advantage.
In any case, nuclear fusion reactions would be less dangerous than fission reactions, as the chemical elements used and those produced in fusion would not themselves be radioactive.