Also I don't know what kind of car you drive but you might want to start making sure you can get it going pretty fast as a explosive nuclear blast can create winds of 500 mph.
I am by far no expert on the subject but I wonder how long anyone has after that event.
An accident/meltdown at a nuke power plant CANNOT result in a "nuclear blast" similar to an atomic bomb. Simply not the right types of materials and completely wrong configruation.
About the worst case scenario would be a steam/hydrogen explosion in the reactor vessel that breached the containment and released radioactive material. The problem here wouldn't be outrunning 500 mph winds and a shockwave, but trying to evacuate along with everyone else in the area. A full tank of gas in the car does nothing when all the roads turn into parking lots.
Unless you are lucky enough to be one of the first ones on the road, you are going to be there a while, so stock up on potassium iodide pills and hope for the best....
Siting that plant just north (und upriver) of NYC had to be one of the stupidest moves imaginable.