Well in you hazmat scenario #2 just to set some things straight about Chernobyl as I lived 200 miles from there. It's not that it was udetected but it was covered up. Russian gov't knew exactly what was happening but didn't let the public know. Polish gov't informed us after they got a wiff of stuff going wrong from Swedish gov't. Moscow denounced Polish news as nothinn more than a lie just to later on launch an emergency responce operation which meant nothing more than relocation. Think about it this way as well. If you have a nuclear facility they will know if there is a leak unless they choose not to install radiation detectors. It is up to them and gov't to let you know what's going on. Living in free country like the US I don't thing me or you have anything to worry about. And as far as the nuclear blast survival goes... just remember old educational films: all you have to do is duck and cover...