How does a nuclear reactor generate electricity?

A nuclear reactor generates electricity by using nuclear fission to produce heat, which then drives a steam turbine connected to a generator.

In a nuclear reactor, the process begins with nuclear fission. This is a reaction in which the nucleus of a heavy atom, such as uranium-235 or plutonium-239, is split into two or more smaller nuclei, along with a few neutrons and a large amount of energy. The neutrons released in this process can then trigger further fission reactions, creating a self-sustaining chain reaction. This is controlled in a nuclear reactor to prevent it from escalating into a nuclear explosion.

The energy released in the fission process is primarily in the form of heat. This heat is used to produce steam from water in a secondary circuit. The steam is then used to drive a turbine, which is connected to an electrical generator. As the turbine spins, it turns the rotor in the generator, creating an electromagnetic field that induces a flow of electric current. This is the electricity that is then distributed to the grid.

The nuclear fuel in a reactor typically lasts for several years. Once it has been used up, it is replaced with fresh fuel. The spent fuel is highly radioactive and must be carefully managed and stored. It can also be reprocessed to extract any remaining usable material and reduce the volume of waste.

The process of generating electricity in a nuclear reactor is highly efficient, as a small amount of nuclear fuel can produce a large amount of energy. However, it also presents significant challenges in terms of safety and waste management. The potential for catastrophic accidents, as seen in Chernobyl and Fukushima, and the long-term problem of nuclear waste disposal are major concerns in the use of nuclear power. Despite these challenges, nuclear power remains a key part of the energy mix in many countries, due to its ability to provide a stable, low-carbon source of electricity.