How nuclear power works

The process of generating nuclear energy is actually similar to that used in traditional fossil fuel plants. Both heat water to create pressurised steam and this is then used to turn a turbine generator. The difference is that rather than burning gas or coal, nuclear power stations generate heat by splitting atoms in a process known as nuclear fission.

In nuclear power stations nuclear fission is controlled and the energy generated is harnessed, but fission happens naturally every day. Radioactive elements such as uranium, constantly undergo fission very slowly, emitting radioactivity all the time.

Within a nuclear reactor fission is induced by adding an additional neutron to a uranium atom, which makes the nucleus unstable, causing it to split. When this reaction happens an extremely large amount of energy is released, particularly as heat, which can be used to create steam and drive turbines.

Every aspect of the nuclear generation process is very closely monitored and controlled. The chain reaction that takes place in the core of a nuclear reactor is controlled by control rods which absorb neutrons and which can be inserted or withdrawn to set the reactor at the required power level. The fuel elements containing the uranium fuel in the form of pellets are surrounded by a substance called a moderator. The moderator serves to slow down the high speed neutrons travelling around the reactor core in order to generate the right amount of energy and to maintain safety. The reactor can be shut down very quickly and safely, for example, by the complete insertion of the control rods.