[q1w2]

See - this is exactly the kind of irrational comment that is a problem. "multi-kilometer" "1%" "catastrophically". ...these are all emotionally driven elements to an argument that does not hold water under scientific scrutiny.

Reactors like Chernobyl and Fukishima are not built today and cannot meltdown. The chance of meltdown is nearly 0%. ...and the danger of meltdown on a modern reactor is like what happened at Three Mile Island (which is basically nothing). No one died, nor was even irradiated. ...and even that type of meltdown is no longer possible.

...and finally "multi kilometer" is not even that big. The Earth is 300 million square kilometers in area. Even if your estimate was correct (which it isn't), then it still wouldn't be a big deal.