Migration of Fallout and Fallout Simulants into Soils

摘要

A series of tests was performed to determine whether radioactive fallout would migrate vertically downward through soils. A thin layer of fused or leachable fallout simulant (Monterey sand coated with barium 140-lanthanum 140 or of natural fallout (fission products in soil) was spread on trays containing frozen soil mixtures. The trays were alternately thawed and allowed to refreeze, with radiation-level measurements made periodically. After a number of thaw-freeze cycles the frozen soils were vacuumed to remove surface activity. Core samples of the soils were taken and layers of the cores were counted to determine actual migration. It was concluded that migration did occur by leaching and particle movement, and that particle migration occurred only in soils having a wide range of particle sizes. A single vacuuming removed most of the detectable activity. (Author)