In the small town of Kalkar in Northern Germany, there is an amusement park with an unusual ‘Alpine Experience’ climbing wall that looks like a power station cooling tower … because that is exactly what it is, or rather was.

The decision to build a prototype fast breeder power station in 1972 was taken because this type of reactor would be powered by the plutonium produced in conventional nuclear power stations, and would therefore produce more fuel than it consumed.