They may include a few Canadian nuclear reactors along the border - but they only include American residents in the calculation of how many people live within a certain radius of these reactors.

So it doesn't reveal how many people live near these reactors, only how many Americans live near them.

You can do the same in St. John's (the capital of Newfoundland and Labrador), Canada:

http://i51.tinypic.com/x52ern.jpg

The two cities actually have very similar architecture:

http://www.youtube.com/watch?v=BRU1jcSrk-U