Nuclear energy is the most powerful form of energy in the universe.
There are two ways of producing it and both ways release enormous amounts of energy.
- One way is to split the nucleus of an atom. This process is called nuclear fission.
- The other way is to join together, or fuse, the nuclei of two atoms. This process is called nuclear fusion and it is happening all the time inside the sun.
In 1938, scientists for first time split the nucleus of an atom. All the nuclear power stations built so far use the heat from nuclear fission to generate electricity. Scientists are still trying to find a safe way of obtaining energy from nuclear fusion. When they discover how to do this, we may have power stations fueled by nuclear fusion.
Nuclear fission takes place when the nucleus of a uranium atom splits, releasing neutrons. These hit other atoms, causing them to split, and so on. This ongoing process is known as a chain reaction.
There are about 420 nuclear power stations in the world. They produce almost 16 per cent of the world’s electricity.
A nuclear power station works in a similar way to an oil-fired or coal-fired power station. The difference between the two types of power stations is in the fuel they use to heat the boilers. Inside a nuclear power station, energy is released by nuclear fission in the core of a piece of equipment called the reactor. The energy heats water in the boiler. The water boils and produces steam. This steam burns the huge turbine wheels, and the turbines drive the generator that produces the electricity.
Nuclear fission must be carefully controlled. The fuel inside the reactor is a metal called uranium. When the nucleus of an atom of uranium is split, the neutrons released hit other atoms and split them in turn.
More energy is released each time another atom splits. This is called a chain reaction.
Inside the reactor in a nuclear power station, the nuclei of the uranium atoms are split.
Nuclear reactors release another kind of energy called radioactivity.
If radioactivity escapes into the atmosphere, it can quickly cause serious damage to humans, animals and plants. This is why a nuclear reactor is sealed inside a shield of reinforced concrete.