oor See | NV Steet feces be oo HON Se fei tt—Py Aer hes fey 3 wa el _ heer lie flea FORECAST FALL=OUT PLOT Be Procedure for Ground Forecast of Fall-Out ‘Contamination from Nominal Bombs Exploded at NPG from 500 Ite Towers. (Noto: ir drops do not ,roducc any appreciable fall-out). (1) Cte ft?fie tae 77" Yo Location and Intensity of Maximum In order to find location ond intensity of maximun fall-out eren assume that all of the activity of the bomb is located at ca point somevihat lower than the center of the mushroom of the atomic cloud. Then follow the trajectory cf a 125 micron particle whose density is 2.56 pm/em’. This procedure is recom= sonded since the ND of the soil at NFG is between 100 to 150 microns. i se This means that the particle is located approximately 7000 ft. from the top of the mushroom end falls with the speed of 15,000 ft. per how down to 20,000 ft. msl, and at the rate of 12,000 ft/nr from 20, 000 ft. down to the ground. This is based on Stoke's 5 13 D= OB a fun - g cs MEINE Vie (Sienatutr of pe ie Aeon maximum angular wind shear in the region from 10,000 ps AV = Ly (toh. (Person 4 ~ F Lon ( 30-5 = go) y/15 - - = = Equation 1. .§ 1¥ aa as change in clas? ieatie Pe: i¢ a te ———— ty aetherityof ¢ he Classitieatws seae-~ rgy Contit tyes U. 's. Atemic Ene (Late) AEASG... Law and the difference in rato of fall ig due to change of viscosity of the air with temperatures. Using the above data it is possible to locate the maximum fall-out area on a mape Sec paragraph (8) below for detailed analysis of the ethod used to obtain the location of thc maximum fall-out aren. It should be noved that the maximum full-out occurs between two to three hours after Hehour ‘ince the averare cloud rises to approximately 40,000 Me msle The actual time of fulleout depends upon the terrain, the height of the tropopause ond the equivu.cent KT of the bomb. In the cvent that the maximum fall-out from o nominal bomb does not oceur within three hours, then the falleout will be generally less contominating. If the maximum occurs in 1g hours or le s the fall-out will be quite intense and highly contaminatinpe To evaluate the maximum felleout using intes ajecoted infinity dose in rocntgens, the following cmpirical relation may be used: 3 ~ Y = Ite to 0,000 [te msle maximum wind specd sheer from 19,000 ft. to 40,000 fte msl. Equivalent KT of the bomb. A salt (2) Tho area covercd by the different integrated cossc lines m3> .eined as follows: (a) The arca of the maximum fall-out riven ebove is very smi (bv) Around the maximum fall-out point draw an cllijse whose It is so small in fact that it may bo taken ns a pointe. fall-out point is given by Equation 1. eee ce be The valuc cf this maximw arce varics between 150 +to 300 square miles. The mejor axis of the cliipso will be dravm parallel to the fall-out plot of the 125 micron particls ss shovm in paragraph (8) below. That focal point of the cllipse which is ncearcst to rround zero Will be placed at the theorctical maximum fall-out poi point. The outer boundsry of the cllipse will indicate the integrntcd isodose line obtained by dividing thy valuc of Equation 1 by approximatelyt oor 5Se (3) Similarly, an clliptical aren of from 500 to 1000 square milk will be drawn about the maximum fall-out point. The integrated dose value of th. linc bounding this arca is approximately one tenth of the ‘valuc obtained by Baty Equation le (4) Starting with Ground Zero and using the fall-out plot of th micron particle indicutwd in paragraph (8) a s a guide, draw . rectangular ar.from 3000 to 5000 square milese Then proceed to fit this rectanpular areca eravn: ground zero and around thc maximum fall-out point somewhat as indie: ted in rirte graph (8) bolow.e The line bounding th: this, Arsh, has,Qovaluo of approximrtcly ene fiftieth of the valuc obtain.d rehicntntori '.