if you start with the "duct tape and plastic"....a positive ventilation structure that would prevent contaminated particles from entering... with some decontamination station provided for anyone needing to exit/ re enter

presumes you are outside the immediate blast and thermal effect range and plan on sheltering in place...that the device is a fission, or fission-fusion-fission device that is somewhat dirty and produces decay daughters from the fissionable source that are bone or tissue seekers in the human body... most likely source material of plutonium or uranium and fission produced radioisotopes (the usual suspects) strontium a +2 oxidation element that would replace calcium and magnesium in the body....cesium a +1 oxidation that would replace potassium and sodium, and iodine found in the thyroid... stores of potassium iodide or equivalent, vitamin or mineral supplements

alpha, beta and gamma radiation... neutrons would be present at the initiation, but found only in fissionable materials..

alpha is the easiest to defeat, but because of the size the most damaging if allowed to enter the body... check of food stuffs and R95 or N95 masks...decontamination routine showering... usually has about a 10cm decay range

beta is a high speed electron, small in size but is still ionizing and disrupts about 1000x the area provided by a strike of a tissue containing atom/electron in the body

gamma...high energy electromagnetic wave...ionizes tissue...travels in straight line, so entrance to a earth shielded shelter needs to have a right angle separating the living area and outside entrance

having a 3 month supply of food and water would be a start...burn supplies and radiation monitoring equipment (monitors that rely on a Geiger-Muller ionization tube will block alpha and beta by the detector tube construction) so probably a scintillation counter would be the best...

my bet on a location would be a port area where a device could be entered in a conex container...

a good thought problem, but a couple dozen dedicated individuals shooting out power stations across the Eastern seaboard would be a whole lot easier to accomplish, and a whole lot cheaper

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