[Updated November 2017: Updates to links]
Above is a nice little Geographic Information System (GIS) from the journal Nature, depicting the number of people around the world living within 75 kilometres of a nuclear power plant. This example uses a Google Earth map to depict all of the world’s nuclear power plants and show population density and distribution. Clicking on the coloured circles reveals more data, including the population within 30, 75, 150, and 300 kilometres of the power plant.
The population data from originally generated by Columbia University’s Center for International Earth Science Information Network (CIESIN). You should also check the original article from Nature which has a bit more detail. The KML for Google Earth can be downloaded here.