Well, being hit by a tsunami that washes away all the backup diesels would be a problem, and battery power to only last 8 hours...
It’s a bunch of problems coming together....think of it as the whole 3:1 engagement rule...except you don’t have the option to retreat when the odds are stacked against you.
I wondering why they didn’t have safety back-ups like an auto nitrogen purge to keep the roof from blowing off the reactor building from hydrogen build up?