[sir_bearington]

> steam explosion that would completely disassemble the pressure vessel and core and would place maximal stress on the containment building itself.

This venturing into the realm of hyperbole, at best. Nothing in your link mentions an explosion that would "completely disassemble the pressure vessel". Stress on the containment building isn't mentioned at all. These statements seem to be of your own invention.

Can you substantiate your claim that a pressure vessel failure stood to compromise the containment building?

> There is a huge different between "didn't explode today", and "can't explode ever"

Again, we set up our safety measures such that the danger is contained even if a meltdown occurs. Even the most scrutinized designs may fail. Humans are never perfect. You're right: no plant can guarantee that it can't fail. That's why safety measures are built to withstand failure.