Numerical simulation for the movement of cesium-137 in grounds

Fukushima Dai-ichi nuclear disaster occurred by Great East Japan Earthquake in 2011. As the result, a lot of radioactive substances was discharged to atmosphere and deposited in surface of ground by rain. In damaged area, decontamination has been conducting. Usually decontamination for the ground is digging out for 5 cm from the surface of the ground, but its safety and validity is apprehended. In this study, permeation behavior analysis of radioactive substance in the ground was carried out in order to prepare new decontaminations. Specifically, behavior and advection-dispersion analysis was conducted by advectiondispersion equation was embedded a term that considered half-life. As a result, it is found that this analysis method has enough validity by comparing analysis result with result on the spot. Furthermore analytic evaluation for the current decontamination is performed.