The reactor fleet is old, and only 36 units have a retirement date
The world’s operating reactors are old, and older than the public conversation about new build suggests. By capacity the average operating unit started up 32 years ago; the median unit started up 39 years ago. Of 419 operating reactors, 193 are 40 years old or more and 44 are past 50. Between them the 40-plus units hold about 178 GW gross.
Where the old ones are
Age here is this year minus the start-up year on record, counted from our data as of the August 2026 release of the Global Nuclear Power Tracker.
- The United States has 72 of its 94 units at 40 years or more.
- France has 36 of 57.
- Canada has 12 of 17, and Spain 5 of 7.
- Switzerland and Sweden have every one of their units at 40 or more.
At the other end, China has none: its 61 operating units average 10.5 years. India, Pakistan and the UAE are young fleets too. The full table is on the fleet age page.
The retirement data is thin
Only 36 operating units carry a planned retirement year in the tracker, and 17 of them fall by 2036. That is not because the other 383 will run forever. It is because most retirement dates are not decided until a licence decision, an economic review or a political one forces them.
Two cautions follow. A planned year is a forecast, and dates move in both directions. And this dataset does not hold licence expiry for any unit, so it cannot tell you which reactors have had their licences extended, and we do not present it as if it could.
Why it matters
A fleet this old is not a fleet about to fall over. Reactors are refurbished and components replaced, and the age of a unit is not its condition. But it does mean that a large share of low-carbon capacity depends on decisions that have not been made yet, in a handful of countries that hold most of it. Start with the compare page to set two countries side by side.