The World's Aging Nuclear Reactor Fleet

What We're Showing

This chart visualizes the age and electrical capacity of the world’s 416 nuclear reactors, using data from the Power Reactor Information System. Each bubble represents a cohort of reactors of the same age, with bubble sizes corresponding to total net electrical capacity (in megawatts).

Key Takeaways

• The global reactor fleet is aging, with more than two-thirds of the world’s nuclear reactors over 30 years old.
• The average nuclear reactor is around 32 years old.
• Reactors built in the last 10 years have a higher average electrical capacity per unit (1000+ MW) than those built 50+ years ago.
• The large number of 30-plus-year-old nuclear reactors reflects periods of nuclear expansion in the 1970s and 1980s, followed by a lull and resurgence over the last decade.
• The number of operational reactors is down from 422 in 2023 to 416 in 2025, with a few reactors shutting down in Germany.