Study of long range transport of radioactive gases and aerosols is necessary to estimate radiological impact to the members of public and environment during nuclear reactor accidents. In the present work, an attempt has been made to employ an atmospheric circulation model that predicts meteorological parameters at the regional and global scales, and a transport model that utilizes these meteorological parameters for the aerosol dispersion. Non-hydrostatic Icosahedral Atmospheric Model (NICAM) coupled with Spectral Radiation-Transport Model for Aerosol Species (SPRINTARS) is used to fulfil this objective, which was used for simulating effects of conventional aerosols on atmospheric pollution and climate system. As a case study, global simulation is carried out for a horizontal resolution of ~110 km to model the dispersion of radioactive aerosol (35S, 131I and 137Cs) releases from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. The results obtained from this case study are compared with the available literature data and other simulation results. The statistical analyses show that the comparisons are better for locations far away (> 150 km) from the emission location, and the results are further discussed. Continuous run of this system will help in predicting the activity concentration in forecast mode, and it may be used for decision support, particularly for long range (> 100 km).