The regional scale atmospheric dispersion of radionuclide ¹³¹I : A simulation method based on WRF-Chem model

Aiming at the dispersion of ¹³¹I in the regional scale, this paper proposes a dispersion trajectory simulation method for ¹³¹I based on the fully coupled online model of the Weather Research and Forecasting-Chemistry (WRF-Chem). The dry deposition, wet deposition and radioactive decay of ¹³¹I have been considered in the Eulerian advection-diffusion equation, which is the three important removal processes of ¹³¹I in the atmosphere. The atmospheric dispersion of ¹³¹I at the early stage in the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident (March 12th to 17th) was used to simulate to validate the method. Comparison between the ¹³¹I concentration of WRF-Chem modeling and the available observations data shows that the dispersion trajectory of ¹³¹I at the regional scale was simulated authentically by this method, which can explain the arrival and duration time of the measurements, indicating that the method can be used significantly as a decision support tool for the early nuclear emergency and evaluate the consequences of the accident.