Author(s): Hiroaki Washizu; Toshiki Iwasaki; Yasuyuki Shimizu; Ichiro Kimura
Linked Author(s): Ichiro Kimura, Yasuyuki Shimizu
Keywords: Sediment transport; Radioactive contaminant; Numerical model; Radiocesium
Abstract: The radionuclides were released to the atmosphere from Fukushima Dai-ichi Nuclear Power Plant (FDNPP) by the accident of FDNPP. Several radionuclides in them such as radiocesium (134 Cs, 137 Cs) and radioiodone (131 I) were absorbed on soil particles of land surface. Such contaminated sediments will be eroded by slope collapse of land, rainfall and so on, and finally will be transported from river to ocean. Thus, the understanding the behavior of sediments eroded from the land surface is important to capture the transport process of sediment-bound radionuclides in the terrestrial area. The purpose of this study is to develop a numerical model for simulating transport of radioactive contaminants by sediment transport in rivers. We derived the governing equations for simulating the concentration of radioactive contaminants of the sediment from the governing equations of the sediment transport model. The proposed model was applied to simplified conditions in rivers to evaluate the performance of the model, and to discuss the mixing process of radioactive contaminant supplied from different origins. The numerical results show that the proposed model can be a potential tool to simulate the transport and deposition of radioactive contaminant in rivers.