EPR vs AP1000: active safety against passive safety
These are the two Generation III+ pressurized water reactors the West actually built. Framatome's EPR bets on redundancy: four loops, about 1,630 MWe net, double containment, four active safety trains and a core catcher. Westinghouse's AP1000 bets on simplification: two loops, about 1,110 MWe net and passive systems that cool the reactor by gravity and convection with no safety pumps and no operator action for 72 hours.
Figures from the atlas
| EPR | AP1000 | |
|---|---|---|
| Units built or under way | 8 | 21 |
| Operating today | 4 | 6 |
| Net capacity operating | 6,525 MWe | 6,888 MWe |
| Countries | China, Finland, France, United Kingdom | China, Poland, United States |
| First grid connection | 2018 | 2018 |
| Most recent connection | 2024 | 2024 |
| Under construction | 2 | 11 |
| Shut down | 0 | 0 |
| Most powerful unit operating | Taishan 1-1 (China), 1,660 MWe | Haiyang 1-1 (China), 1,170 MWe |
| Average load factor, latest reported year | 75.4 % | 90.8 % |
Data: Global Energy Monitor (CC BY 4.0), IAEA PRIS 2025, Wikipedia (CC BY-SA), Wikidata and Wikimedia Commons. Capacities in net MWe unless stated.
Differences
- Power: the EPR is about 1,750 MWe gross and 1,630 net by design, with operating units delivering between 1,600 and 1,660 MWe net; the AP1000 1,250 gross and 1,110 to 1,170 net depending on the country.
- Loops: four in the EPR, two in the AP1000.
- Safety: four redundant active systems, double containment and a core catcher in the EPR; passive residual heat removal by convection, passive containment cooling and in-vessel retention of core damage in the AP1000, with a 72-hour non-intervention period.
- Performance: the EPR is credited with a 65 GWd/t burnup and a 37% thermal efficiency.
- Where they are: EPR at Olkiluoto, Flamanville, Taishan and Hinkley Point C; AP1000 at Sanmen, Haiyang and Vogtle. The first EPR connected to the grid was Taishan 1, in June 2018, with commercial operation that December.
Frequently asked questions
Which is bigger?
The EPR, at about 1,630 MWe net against 1,110 to 1,170 for the AP1000. Both are among the most powerful reactors in operation; the atlas ranking places them.
What does passive safety mean?
That cooling in an accident does not depend on pumps or electric power: the AP1000 uses gravity, natural convection and water stored at height, and its design needs no operator action for 72 hours.
Which was built first?
The first EPR connected to the grid was Taishan 1, in China, in June 2018, entering commercial operation that December; the first AP1000s were Sanmen 1, grid connected in June 2018, and Haiyang 1 in August of the same year. The table shows each connection per the atlas.
Animated guides
EPR (The 8 EPR units in the atlas) · AP1000 (The 21 AP1000 units in the atlas) · Compare any two units · Rankings
Sources
- World Nuclear Association, Advanced Nuclear Power Reactors
- World Nuclear Association, Nuclear Power in China
- Westinghouse, AP1000 PWR
- Wikipedia, EPR
- Wikipedia, AP1000
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