Energy locked inside the nucleus
Nuclear energy is the huge amount of energy stored inside the nucleus of an atom. When the nucleus of a heavy atom is split, a tiny amount of mass is converted into a very large amount of energy, following Einstein's relationship E = mc2. Because a small mass of fuel releases so much energy, nuclear energy is used in many fields beyond just electricity.
Uses in daily life
- Generating electricity — nuclear power stations use the heat from fission to boil water and drive turbines.
- Medicine — radioactive isotopes are used in radiotherapy to destroy cancer cells, and to sterilise surgical instruments; tracers help doctors see inside the body.
- Agriculture — radiation is used to kill pests, preserve food and produce improved crop varieties.
- Industry — radiation gauges measure the thickness of metal sheets and detect cracks in pipes.
- Archaeology — carbon-14 dating estimates the age of ancient bones and wood.
Example
In a hospital, a beam of gamma rays from a radioactive source is aimed at a tumour. The radiation kills the fast-growing cancer cells — this is radiotherapy.
Why it is valuable
The key advantage is the enormous energy from a small amount of fuel, with little of the carbon dioxide produced by burning coal or oil. This makes nuclear energy attractive as a low-carbon source of electricity, though its safety and waste must be managed carefully. Just a few kilograms of uranium can release as much energy as many tonnes of coal, which is why some countries with limited fossil fuels turn to nuclear power. In medicine and industry the same technology, used in tiny controlled amounts, saves lives and improves the quality of everyday products.
Key idea
Nuclear energy comes from the nucleus of the atom. A small mass converts to a large energy (E = mc2), used in electricity, medicine, agriculture and industry.