SIMULATION OF RADIOACTIVE TRACER TRANSPORT USING ISORSM AND UNCERTAINTY ANALYSES

Due to the massive earthquakes and tsunami on March 11 2011 in Eastern Japan, Fukushima Daiichi nuclear power plant was severely damaged and some reactors were exploded. Then radioactive particles were widely spread out. In this study, we modified the stable isotope mode of RSM (IsoRSM, Yoshimura et al.) to enable to simulate the transport of the radioactive tracers, namely iodine 131 and cesium 137, by including the dry and wet deposition processes. The control experiment with 10km resolution and the emission estimated by Chino et al. (2011) showed reasonable temporal results for Toukatsu area (eastern part of Tokyo metropolis and western part of Chiba prefecture), i.e., on 22 March, the tracers from Fukushima was reached and precipitated in a significant amount as wet deposition. Thus we conducted 4 experimental simulations to analyze the simulation uncertainty due to different meteorological pattern and different parameters for wet and dry deposition and diffusion. Though the temporal patterns of deposition of radioactive particles were somewhat similar each other in all experiments, we revealed that the impacts to the area mean deposition were quite large.