BATTELLE Dr. Rudolf J. 3. Engelmann NORTHWEST -5- March 12, 1971 The resuspension factors for <3 um diameter and high density (10 g/cc) 238Pu05 particles are desired. A direct answer is not known since we do not know if the tracer would retain its identity, or if it would attach to a host soil particle. In addition the reSuspension factor would be a function of the surface type as well as airborne loading of soil passing over the contaminated area, ‘Consequently, we have to conclude that the plausible estimate of the experimental resuspension factor is still 6 x 1079 to 1077 m-! or greater. However, Fuquay's model in the SNAP-27 review does predict re- suspension factors as high as 0.3 m1 for 1.5 ym diameter particles at a wind speed of 10m/sec. It is anticipated but unproven that charged 238pu05 particles would coagulate faster than uncharged particles with natural dust particles. The electrical forces are present to cause the increased coagulation, but the coagulation would depend upon the relative proximity of particulates. The hypothesized mechanisms for increased coagulation is as follows: Radiation from the particle would electrically ionize the surrounding air. If subsequently the particles became oppositely charged, an electrical attraction between particles would increase the coagulation rate. This increased coagulation rate is the case of coagula- tion in a bipolar ion source. The theory for ionic equilibrium has been developed in the literature. How- ever, we are not talking about an equilibrium condition in time, space, and concentration. For these nonequilibrium conditions, a definite possibility exists that coagulation would be enhanced. Indeed, we propose within to determine the importance of this non-equilibrium charge distribution on enhanced coagulation. We cannot predict the post-impact weathering half-life or factor associated with the Pioneer capsule and plutonic molybdenum cermet fuel as respirable particles of 238pud>. opposed to the < 3 um