SLIDE 14 Comparison of Bikini Ash to unfractionated fallout. The per cent of fallout beta activity due to fission products present on day 26 after formation was tabulated. The hypothetical beta activity was based on a fallout composition which was unaltered due to chemical or physical mechanisms which affected certain fission product nuclides. This unaltered composition was referred to as unfractionated. This unfractionated fallout was calcy}ated from thermonuclear neutron fission data given by Crocker for U (Cr65). The comparison between per cents, based on the measured values of Bikini Ash beta activity and unfractionated fission product beta activity, required conversion of the Yamatera and Tsuzuki data sets (Y¥a56, Ts55) into percent fission product beta,actiyity. That is, we exclude the beggaactivity of the activation products Ss, Ca and the SRgnsuranic nuclide U for comparison purposes. It was assumped by us that U, which represented 20% of the beta activity on day 26 in the Tsuzuki results represented 20% of the beta activity in the Yamatera data. As previously implied, the term fractionation indicated alterations of nuclide composition in fallout debris. The ratio of two nuclides in fallout was often used to describe fractionation quantitatively ($61). The denominator of the ratio was taken to be the activity of “~Zr (Fr61). To quantify fractionation between two nuclides, the beta activity ratios were compared by Freiling (Fr6l1). The term “degree of fractionation” was used by him and represented the range of variability of the nuclide ratio. revi of Ja ese ults indi d to us that the activity, ratios for 13208 P32 Bf Pare, ToeaR and Teacepe (ratioed to measure 95 END beta activity) did not differ by a unfractionated ratios. tor greater than abeut 1. differed by about a factor of 2, and actor 3 re ive rom the Ratios for 186ata, era, fy, Bescy, tobe and !43py the Sr and 1 ractionated ™e, ios. 2976 differeg by about nuclides Y, tobrcrn Peas 18500" 18200 Y35r° tae cept, [ase sad |e 7na were in greater abundance relative to unfractionated debris. DAY 26 COMPOSITION OF BRAVO FALLOUT Nuclide oy aly 3S ®Ca 2371 239 Du (a) Greater Than Hypothetical Sly, Ru, eRnTe 129mrp W3py Wn Hypothetical Thermonuclear Neutron Fission, % % Bikini Ash Beta Activity Total Beta Activity 0.013 8.0 / 0.05 0.20 20 0.0004 0.031 4.1 _ _ _ _ Less Than Hypothetical us r, Sr, Wy Wp Wy Ba, La cy Ae Nb, fete, 132) M1 Oe 44 Pr E54 ; ae gi Approximately SameAs Hypothetical 19