CHAPTER 2 THEORY AND BACKGROUND 2.1 THEORY The ultimate objective of studies in fallout phenomenology is the prediction of militery effects from the operational use of nuclear weapons unler any given field conditions. The variables include: 1. 2. Type and yield of weapon Environment a. Surfeee water b. e. d. e. f. Underwater Surface land Underground Soil type Weather In order to make these predictions 41t is necessary to have a general theory of the formation and subsequent history of fallout matertal. Such a theory mist encomsss several features. First of all there must be a model of fireball dynamics, which determines the mechanism of formation of particles (or drops of water) and the distribution of the particles in the cloud. The mechanism of varticle formation for surface or subsurface detonations is more complicated than a sirple vaporization and condensation of earth or water with the incorporation of fission products. There are a number of ways in which the activity may be associated with the particles. The activity may be derosited on the surfaces; it mey be dispersed uniformly through the particle volume; or it may be dispersed in several non-uniform ways through the particle volume. Pvidently, the mode of association is denendent upon the mechanism of particle formation and unon the subsequent histery of the particles, which may croduce chenges such as cseclemeration and lecching by water. The condensation process is not thoroughly understood and probably varies with different detonation surfeces, The factors which determine the particle size distribution of the condensate have not been estzblished. In some cases, particularly underground shots, material may be thrown through the fireball without veporization or even extensive fusion. 14 SECRET — RESTRICTED DATA