Scenario building

Via MR Clive Crook and some are wondering the following:

From the start of this calamity I have wanted to know, “What is the worst that can happen at these nuclear sites? Suppose everything that could go wrong does go wrong: what then?” I still don’t know the answer. In what I have read so far–dozens of articles–nobody who knows what he is talking about has spelt this out carefully.

I felt that this was the case during the subprime meltdown as well. The only scenario that was offered from a high level Treasury official was "God help us all". Interestingly, the only direct assistance toward the nuclear meltdown the supposed advanced industrial nations such as the United States and France have offered is to airlift its citizens out of the country.