I would bet against such a “dead zone”, given what we know about the radiation releases so far.
Of course, some kind of unforeseen catastrophic release could happen, but that is looking increasingly unlikely given the decrease in the tempo of catastrophic events.
Well that's good news then. I certainly don't wish it on them. This is a once in a millenium catastrophe as far as I can tell and nuclear power is still needed. Something this terrible is still awful, though,