Scenario: You are in a cabin on a hunting lease, and you hear on the am radio that the nuclear power plant seventy five miles to the north was just hit by a tactical nuke on a cruise missile that somebody shot out of a back of camper-van. It's bad, but it's not quite like Fukushima and it sure isn't like Chernobyl! Yes, it was a nuclear explosion, but they said the reactor core was fairly well contained, as these things go, and they think that everybody outside of the 50 mile radius should be okay as long as they shelter in place and take iodine. The problems are that you don't have those red iodine tablets, and you don't even have Lugol's iodine. Your sister took the jeep back to the city, and she'd have to drive right past (within nine miles of) the power plant to get to you. The nearest town (in the other direction) where they might be handing out tablets is a 27 mile hike down a lot of dirt roads.
There's a cold front on the way, and it would probably blow that cloud of stuff on you before you could finish hiking down the road to that town, so you only have a couple of hours to act.
Here's what you do have on hand: