0018933 APPENDIX E Derivation of Formula for Percent Mo Left in Cloud The formula given in Chapter 3 for the percent Mo?? left in the cloud is based on a material balance for some nuclide, Y, It can be derived as follows: Let Y; = atoms Y formed in the explosion e Y. = " " left in cloud Yro = " "in fallout Mop, * atoms Mo?? formed in the explosion Mo, zs oH" " left in the cloud Mogg? " " in the fallout y ® fraction of Mo?? atomsleft in cloud k the ratio atoms Y: atoms Mo?? formed in thermal =S neutron fission, a constant [R99¢4)] e = R-value for nuclide Y in explosion [R9%x)] cz" Rr] Fo aes Ye " it ne * w eh cloud tt fallout oooee (1) Yo Yro Mo, x Yr/Mo ee Moy, x k x ® Ry] E SAND BRUNO PGa