STUDIES OF ISOTOPE EFFECTS IN FISSION-PRODUCT RARE GASES

Abstract

Part I describes a series of experiments concerning the diffusion of fission-product rare gases from uranium oxides, and other uranium compounds. Abnormal enrichments in Xe131 and Xe132 were found in low temperature fractions of xenon evolved from some of the oxide powders. The results for U3O8 are in agreement with the earlier work of Kennett and Thode in this laboratory. The isotope enrichments in Xel31 and Xel32 are explained in terms of a sphere model for diffusion, and concentration of xenon precursors in regions of low activation energy. Direct expert- mental evidence is given for the concentration of fission-product iodine in regions of low activation energy. Part II gives the results of isotopic analyses of rare gases from stone meteorites, the atmosphere and natural gas. The analyses revealed the presence of fission-product xenon in the atmosphere (possibly from spontaneous fission of Pu244 in the early history of the earth) and also fission-product xenon (from spontaneous fission of υ23θ) in natural gas. Fission yield discrepancies at Xe131 and Xe132 for fission-product xenon in the atmosphere and in natural gas are explained by analogy with the results of Part I.