Just a reminder that some of the old threats are still around (and hence that AI is not only something that can go hideously badly, but also some thing that could help us with the other existential risks as well):
EDIT: as should have been made clear in that post (but wasn't!), the existential risks doesn't come from the full fledged nuclear winter directly, but from the collapse of human society and fragmentation of the species into small, vulnerable subgroups, with no guarantee that they'd survive or ever climb back to a technological society.
Perhaps not, but I'd expect you'd flip a switch, and then the automated systems would shut it off, or something to that effect.
So, set it to shut down automatically after 36 hours without operator action, and it will be fine.
Why didn't they have that problem at Three Mile Island?
You expect wrong. Nature isn't rubber padded, and technology isn't friendly magic. You flip switch, control rods go in, the chain reaction stops, the decay heat continues.
It is 72 hours after the full shutdown, that it melts itself down. edit: or to be pedantic, gets outside design parameters; the melt may take another couple da... (read more)