Where the world's reactors sit: on the coast, on a lake, or inland
A nuclear plant is a heat engine, and a heat engine needs somewhere to put its waste heat. That one fact decides more about where reactors go than any other, and it is easy to check against the data on this site.
We hold a position, an elevation and a distance to the water for every operating site whose coordinates are exact (positions that are only approximate are left out rather than guessed). That is 171 sites, 416 operating units and about 402 GW gross.
The split
- On the sea coast (within 3 km of the water): 72 sites, 185 units, about 188 GW. That is just under half of the capacity we can place.
- On a large lake (within 3 km, and not the sea): 14 sites and 41 units, in the United States (8), Canada (3), Russia (2) and Ukraine (1).
- Well inland (more than 50 km from the sea and not on a large lake): 73 sites and 165 units. These sit on rivers or other inland water.
The rest, between about 3 and 50 km from the sea, are neither.
By country
The countries with the most coastal sites are China (18), Japan (9), the United States (8), South Korea (8) and France (5). For China, Japan and South Korea that is every site we can place. For France it is 5 of 18 and for the United States 8 of 54, where most plants sit on rivers and lakes.
Low and on the water
Eighteen sites, with 55 units between them, are both on the coast and within 10 m of sea level according to the terrain model. That is a fact about where they stand, not about how they are protected. Sea walls, site grading and flood barriers are design choices that this dataset does not hold, so a low site on this list may be well protected.
The highest operating site by the same measure is the Armenian plant at about 936 m, followed by Trillo in Spain at about 849 m.
What to take from it, and what not to
These figures are context. The elevation comes from a 30 m terrain model that two independent versions agree on to a median of 6 m, and it can be off by tens of metres on steep or coastal ground. The distance to water is measured to a generalised coastline, so anything under a few kilometres is not resolved. Neither number says anything about flood risk, which depends on the design basis, the local surge and tsunami record, and the protection built at each plant.
You can see the numbers for any plant on its page under Elevation and Setting, and put several side by side on the compare page.