Why isn't most of America a nuclear wasteland after all the nuclear reactors that should have breached a long time ago?
Actually the History Channel's TV series, Life After People
addresses this one. American Nuclear power plants were built with extra strong containment buildings that can absorb much of the blast even during a full melt down.
The only areas at risk from radiaiton would be a few miles around the plant and many of the plants are located in rural areas.