The defence in depth concept is a central tenet of the safety of nuclear power plants.
The corresponding underlying principles were applied right from the start in the construction of the first nuclear power plants and have been continuously developed on the basis of international operating experience.
The reactor pressure vessel is enclosed by the containment as the third barrier. This consists of a steel primary containment and a concrete secondary containment.
With its pipelines, shut-off valves and other components, the cooling circuit, together with the reactor pressure vessel, is the second barrier for trapping radioactive substances.
The reactor pressure vessel, together with the water’s cooling circuit, is the second barrier for trapping radioactive substances.
