CHAPTER 17 can be expressed in terms of yield and burst depth: max _ 1500 y2/3 {e + 33/3 (The number 33 represents atmospheric preare at the surface in ft of water; thus, d + 33 represents hydrostatic pressure. ) Values of scaled base-surge radius and scaled time for the four underwater test ahots, based on visual extent of the surge, are given in Table 17-3, reproduced from Ref. 47 , which contains a discussion of the principles of scaling used. The following expressions for ecaled radius were developed by graphical methods of fitting to the values of Table 17-3, and the application of correction factors to bring calculated dose rates into agreement with observed ones. Very Shallow and Shellow: Rye -[5-8 10819 (tye + 0-73) + 0-802)°. Deep: Re. = 16.7 logyo tee * 4,54 Cy, Very Deep: Rg, = [7-32 logig (tye - 1) + 1.83] c. 7-4) The term C, which has the value 0.8 is the correction factor applied to bring calculated dose rates into agreement with cbserved ones. The value indicates that the "radiological” redius of the surge is less than the visual photographic radius. E. Radiological Aspects of the Model 1. General Characteristics The radiological characteristics specified for the model include source strength, activity distribution, and air-atteriation behavior. In the model, the source is homogeneous. Source strength is proportional to yield, Y. Energy emission rate is that of un- fractionated fisaion products. An "effective attenuation factor" it, for air attenuation is used in dose-rate computation. Dose-rate ee om we computations for a given point are made at 15-sec intervals, starting at 30 sec after burst. Dose is camputed from these dose rates in 15-sec increments. The model predicts excessively high dose rates at times earlier than 30 sec because only air attemuation is considered. At these early times, attemuation by water thrown up by the explosion, or inhomogeneities in the distribution of radioactivity, which have been ignored, probably accounts for much of the difference. These early dose rates probably make a significant contribution to the total dose only in the region near surface zero where other weapon effects, especially underwater shock, are of dominating importance. C Cort E L B A L I A V A BEST 17-47 wee mene oe eee er eee ee