Of all the technological innovations of the last century, nuclear power is perhaps the most controversial.
Nuclear power stations use reactors to garner the heat released from nuclear fission to turn water into steam to power turbines. Reactors have also been used to power submarines and spacecraft.
Nearly 20% of the world's electricity is produced by more than 400 nuclear power stations, yet some environmentalists argue that these benefits are outweighed by the problem of nuclear waste.
But proponents of nuclear power argue that it is an efficient source of energy that does not produce large amounts of greenhouse gas.
