I live just within the 15 mile zone of a power plant, so pretty much if there's a meltdown, I'm dead. Woo!
Not exactly. There would be a series of events leading up to the loss of the reactor core and any number of those events would trigger a site-area or general emergency. This in turn would involve state and local officials evaluating the situation and deciding on evacuation or shelter-in-place options.
In the event of a meltdown of a civilian reactor short term shelter-in-place outside of the five mile exclusion (immediate evacuation) zone would be used until they calculate the plume and fallout zone, and once they did that everyone not directly effected by the plume would be permitted to go home.
Now, that is assuming that the situation got that far out of hand. American civilian power plants really cannot melt down on this scale for a variety of reasons, and if they did there are systems in place to mitigate the effects... so it wouldn't be a big dramatic explosion and mess like Chernobyl.