EPR is an abbreviation of European Pressurized Reactor or Evolutionary Power Reactor. A generation III+ pressurized water reactor (PWR). With its 1,600 Megawatt (MW) capacity, it is not only among the largest in the world, but also the latest proposals for how safety systems in a nuclear reactor should be designed.
The EPR is designed to use uranium more efficiently, using using nearly 20% less uranium per kilowatt-hour of electricity generated than past Generation II reactors,
Safety systems #
As a characteristic of generation 3, the EPR is designed with passive safety – i.e. measures that work due to the laws of physics, without any form of human intervention or influence.
It has four independent emergency systems in the form of water basins and generators [1]. They are located in different places in the building, and each of them must be able to cope with the necessary cooling in the event of an accident. Missing the first, the second takes over. Missing the second, the third takes over. Missing the third, the fourth takes over. It can provide cooling for up to three years after shutdown.
Underneath the reactor tank itself is a so-called core catcher [2]. In the event that all safety systems fail, the core may melt down. With a temperature of 2,000-3,000 degrees, it physically melts down in the basement passage, where the liquid mass – without any intervention – is automatically retained in a steel basin covered with a special type of concrete which fuses with the fuel and cools it down. At the same time, plenty of water – in the mixture the element boron, which inhibits the development of heat – flows in.
The influx is not controlled by humans, but by gravity. And the combined package means that the melted material solidifies within a few days, after which a major indoor clean-up must be carried out. Nothing has left the building yet.
Of course, all these safety systems do not mean that accidents are excluded, which is not the point of them. Accidents are possible with all technologies.
Safety systems do not prevent accidents from happening – they are about making the accident as small as possible if something does happen. Like cars that suddenly have automatic brakes if you get too close to a car while reversing.
