Depends on what you mean by "safe" - well-designed nuclear power plants, including Three Mile Island, are unlikely to cause much harm even if they do melt down (as Three Mile Island did), and well-designed power plants are also very unlikely to melt down. Poorly-designed power plants, like Chernobyl, however, are another matter entirely.

I would wager living in the immediate vicinity of a nuclear power plant is no more hazardous to your health than living in the vicinity of a coal-burning power plant, and probably is actually a good deal safer.