Ages 14-18: Educational Resources
Fission and fusion
Atoms are mostly empty space, but they are also full of a special type of energy that we call "nuclear energy". We can use this energy to make electricity.
How do we get enough nuclear energy for electricity? By breaking the centre of the atoms!
The centre of an atom is called the nucleus, which is where the word “nuclear” comes from. Scientists discovered that the nucleus can be split apart through a process called fission.
In a nuclear reactor, nuclei are split apart by bombarding uranium atoms with free neutrons. When free neutrons collide with nuclei, radiation and heat are released and other neutrons are also released. This sets up a chain reaction.
Nuclear reactors are designed specifically to keep this chain reaction called fission under control.
Fusion is the opposite of fission, since it involves things being joined together instead of divided. In this case, joining, or “fusing”, one nucleus with others.
The reaction from joining them together releases a lot of energy.
Keeping a fusion reaction going is very hard – research scientists and engineers are working on ways to keep a fusion reaction going on a large scale. Until they do, fission is the only way to reliably produce electricity from nuclear energy.
Did you know? The sun’s heat comes from fusion
reactions.