How a nuclear power plant works

A nuclear power plant is a thermal power station designed for the production of electricity in which, as opposed to conventional fuel (such as coal, natural gas, peat), the heat is generated as a result of the splitting of the uranium nuclei that occurs in the nuclear reactor, i.e. fission. In suitable conditions, the chain reaction of splitting nuclei sustains itself, thus enabling the controlled generation of heat.

The energy released in fission reactions heats the nuclear fuel and transfers further into the reactor’s coolant. The coolant can either be led directly from the reactor to the turbine or be used to heat a separate secondary circuit’s water in a steam generator so that the vaporised water rotates the turbine. In the turbine, the vapor’s thermal energy is converted into kinetic energy and further, with the help of a generator, into electricity.

The pressurised water reactor and the boiling water reactor are the most common reactor types in the world. In Finland, the reactors of the Loviisa nuclear power plant are pressurised water reactors. Olkiluoto 1 and Olkiluoto 2 are boiling water reactors.

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  • Tomi Routamo / Deputy Director