量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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The vertical distribution and downward migration of 239+240Pu and 241Am in diverse types of Chinese soils (forest, grassland and desert) were studied. The mean 239+240Pu and 241Am activity concentrations in the investigated soil cores were 0.278-0.692 mBq/g and 0.128-0.373 mBq/g, respectively, while the accumulative inventories were 63-138.9 Bq/m2 for 239+240Pu and 28.3-61 Bq/m2 for 241Am. The global fallout was thought to be the source of these radionuclides as indicated by the characteristic 241Am/239+240Pu activity ratios and 240Pu/239Pu atomic ratios in these samples. The well-founded convection-dispersion equation (CDE) was used to calculate the migration parameters of 239+240Pu; meanwhile a compartment model was employed to compare the migration of 239+240Pu and 241Am in successive soil layers. This is the first work that comparatively studies the migrations of 239+240Pu and 241Am in Chinese soils in realistic environments. Results showed that the migration behaviors of 239+240Pu and 241Am were rather similar; both velocities were less than 0.3 cm/y in diverse types of soils. These findings were compatible with those of short-term laboratory simulation experiments in China.
Distinctive distributions and migrations of 239+240Pu and 241Am in Chinese forest, grassland and desert soils
