Nuclear fission
From Simple English Wikipedia, the free encyclopedia
Nuclear fission is something that happens with atoms and gives off a lot of energy, and is used in nuclear weapons and nuclear reactors. This process was discovered in December 1938 by the German nuclear chemist Otto Hahn and his assistant Fritz Strassmann in Berlin.
Certain types of the elements named "uranium" and "plutonium" can be made to fission. All atoms are small, but atoms of uranium and plutonium are very heavy. At their center is a very heavy ball called a nucleus, which is made of protons and neutrons. If a very large nucleus is shot at with a neutron, it will sometimes break into two pieces. This will release a lot of energy, and also some more neutrons. If those neutrons then hit another atom, they will do the same thing, again and again. This is called a nuclear chain-reaction, and it can release a lot of energy very quickly.
In a nuclear bomb, this must happen very quickly, to make a very big explosion. In a nuclear reactor, this must happen very slowly, to create heat.
In nuclear reactors, fission is used to create heat, which is used to make steam. The steam is then used to power electric turbines which generate electricity.
