I hope your smliley face was serving as your sarcasm tags...ductape and plastic will not save you from anything. The best course of action in a radiation/bio/chem attack is to evac the area...and have food/water/clothes/cash/etc. handy and portable to be used for 1-2 weeks. To prepare for more than that(1-2 weeks); you may as well join a survival group. These kind of attacks are survivable...if you take simple planning measures and realize the situation for what it is.