Radionuclide Fractionation in Debris from a Land Surface Burst

Publisher Website
Google Scholar
Abstract
Two opposite types of radionuclide fractionation have been found in the highly radioactive fallout particles which originated from the first Chinese nuclear test explosion carried out on 16 October 1964. The first type was quite similar to the fractionation that was observed in the highly radioactive fallout particles which originated from the large scale air-bursts carried out by the U.S.S.R. in the autumns of 1961 and 1962. The radio-chemical composition of the particles fractionated in this type was always much enriched in Zr95 + Nb95 and impoverished in Ru103 taking a middle position for most of other nuclides. The particles fractionated in the second type were, just contrary to those fractionated in the first type, much enriched in Ru103 and impoverished in Zr95 + Nb95 The second type of fractionation was never found in the Russian particles that were examined. The fractionation factors as Edvarson et al. defined were measured for some fallout samples. It was found that the particles having exceedingly higher activities among the collected 300 particles were all fractionated in the second type and that the others were fractionated in different degrees, some being fractionated in the first type and others in the second type. The difference in fractionation behavior between the Chinese and the Russian particles may be considered to be ascribed to the fact that the former were produced in a small scale land surface burst, while the latter were produced in large scale air-bursts.