FALLOUT RISK AFTER A MAJOR NUCLEAR ATTACK ON THE USA

Fallout distributions are calculated for nuclear attacks on the contig uous United States. Four attack scenarios are treated, including count erforce and counterforce-countervalue attacks, for meteorological cond itions associated with a typical day in summer and one in winter. The countervalue attacks contain mostly airbursts. To determine fallout ef fects, the population surviving the prompt effects is first calculated . For the prompt effects, a ''conflagration'' type model is used. The counterforce attack produces about 8 million prompt deaths, and the co unterforce-countervalue case projects 98 million prompt deaths. Partia l relocation before attack to low-risk fallout areas at least 15 km fr om potential strategic targets would result in a decrease in projectio ns of deaths by tens of millions. For fallout risk calculations, only the dose received in the first 48 hours (the early, of local fallout) is considered. Populations are assumed to be sheltered, with a shelter protection factor profile that varies for a large urban area, a small urban area, or a rural area. With these profiles, without relocation, the fallout fatalities for all four attack scenarios are calculated t o be less than one million people. This can be compared to fallout fat alitites of about 10 million for a hypothetical unsheltered ''phantom' ' population.