YOIC2s PLANK: Are these values in clove agreesacnt or not? I don't know how to translate the diffusion rate wich inverse with time with his diffusion coefficient. Perha he could do this. RAPP: If I understand Plank correctly what he is saying is tha in the first two hours the peak concentration goes dow inversely with tise. PLANK? BETHEs Yes that is in the first ten hours. This is what you would get, it seena to ne, if yor had fasion in a plane regardless of the diffusion coefficient. LISBYs did you get DOr. Bethe's remark, That it is the approxi observational would indicate that three dizensicnal nodel should perhaps be squeesed down more to a twodimensional. RAPP: That's right. Well, we are quite sure of that. Ve tried te take the maxizun vertical diffusion. We believe that the dif. coefficients should be much, much exaller in the vertical] than in the horizontal and therefore, it would correspond noreloclossly to diffusion in the plane than this particular model. Wel tried to gat here a model of diffusion which would bring the maginus amount of radicactive debris down into the rain-bearing level in such a way that we could make sone sort of analysis of how wach stuff would be rained-out. Derartment sf Trargy Hisves ss 53 PPTL cee