It is not as though the Fukushima operators were blindsided. They knew exactly what would happen if they could not restore power within a certain period of tim

It is not as though the Fukushima operators were blindsided. They knew exactly what would happen if they could not restore power within a certain period of time; they could not restore power and the disaster proceeded as anticipated. What makes modern reactors different is that the worst case is not a catastrophe, and a loss of power does not cause a catastrophe. With older reactors the design philosophy was to make the worst case sufficiently unlikely; with newer designs the philosophy is to not have a catastrophic worst case.