Electricity production
At first glance, a nuclear power plant is very similar to a conventional coal-fired power plant. Both plants convert the energy stored in the fuel into heat. Water is heated and evaporated. The steam sets a turbine in rotation. A generator converts this rotary motion into electrical current.
The main difference between a coal-fired power plant and a nuclear power plant is the type and use of the fuel. In a coal-fired power plant, the coal is burned in a boiler; in a nuclear power plant, the energy stored in the uranium is obtained by means of nuclear fission and a controlled chain reaction. Enormous amounts of energy can thus be generated directly from the atomic nuclei. A single kilogramme of natural uranium can generate about 100,000 times more electricity than a kilogramme of lignite (i.e. about 100,000 kilowatt-hours). This will cover the total annual electricity demand of around 30 average private households in Germany.
Functionality of a pressurised water reactor
Philippsburg 2 and Neckarwestheim II, which are in power operation, are pressurised water reactors. An essential design principle of pressurized water reactors is two separate water circuits. In the primary circuit, the water serves, among other things, as a means of transport for the heat generated during nuclear fission in the reactor pressure vessel. The water transports the heat into the “steam generators”. In this connection between the primary and secondary circuit, the heat is transferred to the secondary circuit. The steam generated there drives turbines, which in turn drive a generator that produces the electric current.