Calculating the vulnerability of synthetic polymers to autoignition during nuclear flash. Final report

: In an experiment that was part of a 1953 nuclear test (Encore), a furnished room exposed to nuclear heat was completely consumed when the fire unexpectedly progressed to flashover. The result of this unique experiment has been called an 'anomaly,' but a flashover under these conditions may actually be typical (and consequently worth exploration). The calculations detailed in this report represent a first approach to this question. Because synthetic polymers in the form of furnishing are more common in modern dwellings than the cellulose-based materials used in the 1953 experiment, we have emphasized the polymers in our calculations. Our investigations have virtually ruled out photochemical processes as an explanation of past or future flashovers induced by nuclear detonation. Our calculations of rapid radiant heating of a few common synthetic materials show they would quickly ignite when exposed to a 25-cal sq cm fluence from a 1-Mt weapon detonated in the air. This result, together with the fact at a higher rate during combustion, suggests that modern dwellings are vulnerable to nuclear-flash-induced flashover. A definitive answer to the question, however, must await carefully planned, full-scale experiments.