Every technology is subject to human error and inherently dangerous. In fact we have many technologies that are way more dangerous to humans than nuclear - cars, chemical plants, pharmaceuticals, etc. There is no rational reason to single out nuclear technologies as being in need of unachievable absolute perfection when we are fine (not ideal, but also not so bad that it's not worth it) with many dangerous ones the way they are. I think it has more to do with irrational fears than rational risk assessments.