As my wife and daughter spend their days 2 miles from a nuclear power plant, I always sweat a little more when they move the level up.
Eh, nothing to worry about, IMHO. Other than with an atomic bomb, terrorists really can't do much of anything to a a nuclear plant, and if they had an atomic bomb, they wouldn't waste it on some nuke plant in a rural area. Nuclear plants are one of the least-viable "bang for the buck" targets out there, in the ratio of how well they are defended and what could possibly be accomplished by attacking one, which isn't much at all.