The Swiss nuclear power plants have been continuously backfitted for several years.
Operators in Switzerland have already invested hundreds of millions of Swiss francs into the renovation of their plants. Certain components of a nuclear power plant, however, cannot be replaced.
These are the components that determine the lifespan of a nuclear power plant. They include a plant’s core, the reactor pressure vessel welded together from powerful steel rings. But its also the reactor pressure vessel that is exposed to the strongest stress.
There are thus regulations that call for the decommissioning of a nuclear power plant (link in german) once the signs of ageing in the reactor pressure vessel have become too great.