Why is plutonium used in nuclear weapons?
The only reason governments researched nuclear energy during the 1940s and 1950s was to develop nuclear bombs. Although nuclear bombs can be made from highly enriched uranium, most of the nuclear weapons countries have decided to use plutonium. This is because plutonium is more ‘reactive’ in its normal state. In other words it takes less extra radiation to be bombarded at the plutonium to cause a supercritical mass which leads to a runaway nuclear chain reaction that explodes into a nuclear fireball. This means that a nuclear bomb can be made much smaller and fit into a missile, for example, than the bulkier uranium. Plutonium can be made very pure for nuclear weapons. As the level of impurities in the plutonium decreases the explosive force can be increased. This pure form of plutonium is called ‘weapons grade’. However even plutonium that has relatively high levels of impurities, such as that used in nuclear power stations, can be used as a nuclear explosive. Such a ‘reactor grade’ p
