It can be as easy as staying inside for a few months, and using respirators and full cover suits when venturing out afterwards. Most radiation is absorbed through a dust we breathe in that sticks inside the lungs. Distilling water for purification is also necessary after a nuclear event. A small amount of preparation can go a long way.I'd assume survival's possible if you're in a safe place like a deep underground bunker. The elites certainly have planed this part for a long time!