A Computer Fallout Model for Operational Type Studies

摘要

This study describes a method of calculating g(t), the rate of deposition on the ground of radioactivity from the stabilized cloud resulting from a nuclear ground burst. Particle fall dynamics are described by the method of Davies as formalized into a computational algorithm by McDonald. The radius of particle arriving on the ground at any time from a given altitude, and the rate of change of this radius with time are described by polynomials in 1/t. A table of coefficients of these polynomials from 200 meters t 50 km above sea level is provided. It was found that a pancake (zero-thickness) cloud is an excellent approximation to a vertically-distributed cloud with finite extent. This, and the closed form of the calculation, make for a relatively simple and straightforward algorithm, one in fact that approaches the ease of a hand calculation. (Author)