": you need to be able to face a situation where _all_ you smart emergency systems fail. "

Totally agree with you here - Until recently, no nuclear power plan was designed such that it could survive failure of all their emergency systems. Hopefully, with the negative repercussions of Fukushima on the industry, engineers are rethinking their approach to Nuclear Power.

See: http://en.wikipedia.org/wiki/Passive_nuclear_safety