Results of Calculations of External Gamma Radiation Exposure Rates from Fallout and the Related Radionuclide Compositions Operation Buster-Jangle, 1951 ABSTRACT This report presents data on calculated gamma radiation exposure rates and ground deposition of related radionuclides resulting from Events that deposited detectable radioactivity outside the Nevada Test Site complex. INTRODUCTION The Events which deposited detectable radioactivity outside the Nevada Test Site complex! are listed in Table. 1. RESULTS Results of the calculations of relative external gamma radiation exposure rate and related radionuclide ground deposition are given in the Appendices. These calculations are described in detail in Ref. 2. The output of the calculation has 30 decay times, 10 from 1 to 21 h, 10 from 1 to 300 d, and 10 from 1 to 50 y. For each of these times and for zero time there are values of the external gammaradiation exposure rate normalized to 1 mR/h, 1 m above the surface, 12h after the event, the associated values of uCi/m2 for each radionuclide, and the total wCi/m?. The 233U, 235U, 23U and 299?40Py data were omitted primarily to keep the output unclassified. Futhermore, the natural uranium contentof thesoil is about one million times that received from fallout and at least half of the plutonium in Nevada and Utah soils comes from worldwide fallout.? Surface roughnesseffects are simulated by using Beck’s values* of (mR/h)/(uCi/m?2) fora relaxation length of 0.16 g/cm?. According to Beck, the concentration of fallout varies exponentially with soil depth, Z, according to the relation C = C,e?”, Hedefines relaxation length as 1/a. TABLE 1. Event Buster Baker Yield, date and placement of Events of Operation Buster-Jangle, 1951. Yield (kt) Date Oct. 28 Air drop 1118 ft Buster Charlie 14 Oct. 30 Air drop 1132 ft Buster Dog 21 Nov. 1 Air drop 1417 ft Buster Easy 31 Nov. 5 Air drop 1314 ft Nov. 19 Nov. 29 Surface Buried 17 ft Jangle Sugar Jangle Uncle 3.5 Placement 1.2 1.2 1