Tornado‐Borne Missile Speed Probabilities

A procedure is developed for estimating speeds with which postulated missiles hit any given set of targets in a nuclear power plant or similar installation. Hit speeds corresponding to probabilities of occurrence of ${10}^{-7}$ are calculated for a given nuclear power plant under various assumptions concerning the magnitude of the force opposing missile takeoff, direction of tornado axis of translation, number and location of missiles, and size of target area. The results of the calculations are shown to depend upon the parameters: $C_{D}A/m\text{,}$ where $C_D=\mathrm{drag}$ coefficient, $A=\mathrm{projected}$ area, $m=\mathrm{mass}$ of missiles; and the ratio, k, between the minimum aerodynamic force required to cause missile takeoff, and the weight of the missile.