Nuclear energy: when atoms explode
Nuclear energy, which is also called atomic energy, is the form of energy that binds together the constituents of the nucleus of an atom. This energy can be released, mainly in the form of heat, with the disintegration of unstable nuclei (Uranium 235 or Plutonium 239, for example).
Uranium is a radioactive metal that is found in certain rocks. It is made up mainly of two isotopes: Uranium 238 (99.3%) and Uranium 235 (0.7%). First, the uranium has to be extracted from the rock. The uranium 235 is then concentrated by a factor of approximately six before the fuel used in nuclear power stations can be manufactured. It takes around 100 kg of ore to obtain 100 g of enriched uranium, which is an extremely concentrated source of energy (the concentration required for military usage is a great deal higher).
In nuclear power stations, nuclear energy is converted into heat to boil water and, as is the case for thermal power stations that use fossil energy, this drives the turbines that ultimately generate electricity.
The radioactive radiation released during the production of energy or by "spent" fuel (nuclear waste) is noxious, particularly in large quantities. Although the level of radioactivity diminishes over time, nuclear waste remains hazardous for hundreds – perhaps even millions - of years.
