The operation of a nuclear power plant

The fission of the uranium atoms produces heat, heat which then transforms water into steam and sets in motion a turbine connected to an alternator that produces electricity.

1. The primary circuit
   In the reactor, the fission of uranium atoms produces a large amount of heat.
   This heat increases the temperature of the water circulating around the reactor at 320 ° C. The water is kept under pressure to prevent it from boiling. This closed circuit is called the primary circuit.

1. The secondary circuit
   The primary circuit communicates with a second closed circuit, called a secondary circuit via a steam generator. In this steam generator, the hot water of the primary circuit heats the water of the secondary circuit which turns into steam. The pressure of this steam rotates a turbine which in turn drives an alternator. Thanks to the energy provided by the turbine, the alternator produces an alternating electric current.

A transformer raises the voltage of the electric current produced by the alternator so that it can be more easily transported in the very high voltage lines.

1. The cooling circuit
   At the exit of the turbine, the steam of the secondary circuit is again transformed into water through a condenser in which cold water flows from the sea or a river. This third circuit is called the cooling circuit.
   On the banks of the river, the water of this third circuit can then be cooled in contact with the air circulating in large towers, called air-coolers.