In order to upgrade the migration / assessment technology of environmental radioactive materials, required for environmental impact assessment of various radionuclides releases and environmental pollution events, we are developing the atmospheric dispersion model with high resolution in consideration of the influence of structures in the vicinity of the facility, the reconstruction method of atmospheric release / dispersion process, and the practical ocean dispersion prediction system. In addition, to develop and advance the aforementioned basic technology, we will acquire the basic data necessary for the validation of radionuclide dispersion model. Furthermore, as an application to the global environmental problem, we promote carbon cycle research in the forest.