According to the International Atomic Energy Agency (IAEA), the United States is currently running 99 reactors, making it the country with the most units online, followed by France with 58 units.
This infographic shows that a lot of the currently still running reactors were connected to the grid in the 1980s, now 29 to 38 years old.
In Germany, where the government decided to shut down all nuclear plants by the end of 2022, all of the 7 still running reactors were built in the 1980s.
The oldest reactors worldwide went online some 49 years ago. One of them is the reactor 1 at Beznau power plant in Switzerland which has been delivering electricity since July 1969.