Assessment of Exposure Doses and Decontamination
ＱDoes radioactive Cs migrate from reused soils that have been stripped during decontamination?
ＡExperiments and analyses have shown that the migration rate of radioactive Cs was low in soils in Japan and that the range of migration was limited.
- Stripped contaminated soils were buried and covered with clean soil, and then sprinkled with 3200～3900 mm of water, which is equivalent to 8～10 years of natural infiltration. The concentration of radioactive Cs was in the range of 1000～3000 Bq/kg in the stripped contaminated soil and less than 40 Bq/kg in the cover and underlying soils.
- In the analysis of the water sampled using a soil-water-collection device that had been installed at the bottom of the underlying soil, no migration of radioactive Cs was observed.
- Simulation of the migration of radioactive Cs for 100 years using an advection–diffusion model showed that radioactive Cs migrated slightly and decayed within the contaminated soil (the maximum concentration at a distance of 10 cm from the contaminated soil will contain a 1％ concentration of the contaminated soil).