Chernobyl was an exercise in quick, dirty, and cheap. New reactor designs are being drawn up that are "inherently safe" -- if the cooling goes kaput the core does not melt its way to China, it doesn't spew radioactive vapor, it just sits there contained.
Is there anyway that the radiation can get out accidentally under extreme circumstances? What if there is a terrorist attack on a reactor? Plus even if there are no accidents or attacks, what do we do with the spent waste that sits around for the next several thousand years years. Even if we bury it, it could work its way into the water supply, or gradually back to the surface.