Nuclear Power Plants in the US

US Nuclear Power Plants, Seismic Hazard, and Population Impact

Over one-third of the US population lives or works within 50 miles of a nuclear power plant. Currently, there are 105 operating nuclear reactors at 65 sites throughout the United States. As the map illustrates, only a few power plants are found in regions with some earthquake risk. The pattern of nuclear reactor sites across the United States shows that the Central US is relatively empty compared to the Eastern Seaboard, the Great Lakes, and the Mississippi River. It is no coincidence that the placement of these power plants follows the population distribution, which has historically followed major waterways and ports. Additionally, the strategic placement of these power plants close to major water bodies also provides the water required to help cool the plant however, the placement near the water’s edge, particularly next to the ocean, increases the risk of damage from environmental impacts such as sea-level rise, tsunami, hurricane, or other extreme weather events.

This map shows seismic hazards, nuclear power plant sites, the number of reactors per site, and the population within a 50-mile radius of each nuclear power plant site. The total US average population within this 50-mile radius is approximately 117.7 million, or 38% of the entire US population. More power plants are seen around the Great Lakes and in the Northeast, with a higher occurrence of populations that overlap within the 50-mile catchment of multiple nuclear plants. Nuclear plants in California are visibly vulnerable to earthquake risk, with one Southern California plant potentially impacting a population of over 5 million. More frequent overlap of nuclear power plants and seismic risk is seen in the Southeast as the seismic hazard appears minimal, though not insignificant. This map is not an analytical tool but allows the user to visualize population size within a 50-mile radius of a nuclear power plant and proximity to seismic hazards.

Seismic hazard data is provided by the USGS 2008 United States National Seismic Hazard Maps Project (NSHM). Seismic hazard is displayed as Peak Ground Acceleration (PGA); the greater the PGA, the greater objects will accelerate horizontally, thus experiencing a greater force. This map specifically displays the seismic event PGA of a 10-in-100 (10%) chance of exceedance in 50 years. PGA is generally used to evaluate building codes; using the Modified Mercalli Intensity Scale (I-X), PGA can be correlated to potential damage (shown in legend) and perceived shaking. Population counts within a 50-mile radius of each nuclear power plant were calculated using the LandScan 2008 TM 30 arc-second Global Population dataset, a statistical approximation of ambient or 24-hour day/night average population.