nuclear power

Nuclear Fission

Energy is released by nuclear fission when the nuclei of large atoms split into smaller nuclei and the tiny bit of mass lost is converted to energy according to Einstein's equation:

The fuels used in nuclear reactors are usually uranium and plutonium. The biggest problem with nuclear fission energy is that the atoms produced, the waste products, are very radioactive. This makes them very dangerous to living things and they have to be stored safely somewhere, in some cases for many thousands of years, until their radioactivity dies down.

In 1986, there was a major nuclear accident at Chernobyl, in the Ukraine. A large cloud of radioactive particles was blown across Europe. Many hundreds of people who lived near the accident site suffered illness because of this disaster.

After this accident, people's attitude to nuclear power became rather negative and many countries cut back on their development of nuclear power. France, however, still relies on nuclear power stations for 75% of its energy needs.

Nuclear power was once thought to be an answer to the world's energy needs. It was thought to be relatively cheap and safe. Now many nations are not so sure. The UK has not opened any new nuclear power stations since 1994.

Nuclear fusion takes place in the core of the Sun and other stars. It is the process in which hydrogen atoms combine to form helium atoms. During that process some of the energy binding the atomic particles together is transferred to electromagnetic radiation energy. It is that radiation that makes the Sun shine. For many years, scientists have been trying to control this form of energy transfer here on Earth, but it is proving to be technically very challenging.

It requires very hot and dense conditions (just as is found in the centres of stars) if the hydrogen atoms are to fuse into helium and producing those conditions is very difficult. The main reason why it is worth trying hard to make this work is that nuclear fusion does not create any harmful by-products. It would therefore be the ultimate source of 'clean' energy.