ENE LPN In fact, this study shows a definite relation between a radionuclide retention that increases (a fractionation thet decreases) with increasing fraction of the time that the progenator, or precursor, elements are refractory, i.e., fraction of the time they are not halogens, rare gases, alkali metals, or tellurium. sizes These results involving all particle are shown qualitatively to apply for several test conditions including coral surface bursts and shallow-water surface bursts. However, we emphasize that for Fniwetok the local fallout is of interest rather than these overall conditions for both local and remote fallout. BEST AVAILABLE COPY The percentage of the total radioactivity of the explosion . residues from all radionuclides that is present in the early fall- out is called the Yearly Lailouc fiacciow” aad produces raetdnal radioactivity on islands and lagoon of the Atoll. For water surface explosions, the value is in the neighborhood of 30 percent. However, for land surface explosions the "early fraction fallout" is higher, with estimates ranging from 50 to 70 percent. Variations in environ- mental and meteorological conditions would result in variations in these fractions of local fallout (Glasstone, 1964, p. 437). We now consider the composition of fallout particles from surface explosions on the coral of the Atoll. Fresh coral debris is largely CaO and Ca(OH)9 (Crocker, et al., 1965) The calcium oxide particles from the surface have different radiological and structural properties depending on whether or not they were melted in the fireball from the nuclear explosion (Lowman, 1960, p. 107). Ge)