I heard once that there are more nuclear reactors in the Snake River Plain then anywhere else, per sq mile. They are not for power, but part of the INEL, for research and other purposes. The power plant for the original nuke sub was developed there. Any SE Idaho pilot ends up flying over it a lot, and the sectional is marked, "For reason of national security blah blah blah, but I feel they are pretty damn reasonable about it in this post 911 world. Stay above 6,000' (it may be 6500', too cold right now to go get the sectional) and you're golden. Pretty much 2,000' or less agl. They DO have a big security force, and if ever forced down there one would be wise to greet them while on your knees with your hands in the air, that's my plan anyway.