Development of local-scale high-resolution atmospheric dispersion and dose assessment system

We have developed a local-scale high-resolution atmospheric dispersion and dose assessment system (LHADDAS) for safety and consequence assessment of nuclear facilities and emergency response to nuclear accidents or deliberate release of radioactive materials in built-up urban areas. This system comprises three parts: preprocessing of input files and main calculation by a local-scale high-resolution atmospheric dispersion model using large-eddy simulation (LOHDIM-LES) and a real-time urban dispersion simulation model based on a lattice Boltzmann method (CityLBM), and postprocessing of dose calculation by a simulation code powered by lattice dose-response functions (SIBYL). LHADDAS has a broad utility and performs excellently in (1) simulating turbulent flows, plume dispersion, and dry deposition under realistic meteorological conditions; (2) simulating real-time tracer dispersion using a locally mesh-refined lattice Boltzmann method; and (3) estimating the air dose rates of radionuclides from air concentrations and surface deposition in consideration of the influence of individual buildings and structures. This system is promising for use in the safety assessment of nuclear facilities (as an alternative to wind tunnel experiments), detailed pre/post-analyses of local-scale radioactive plume dispersion in case of nuclear accidents and quick response to emergencies resulting from the deliberate release of radioactive materials by terrorist attacks in central urban district areas.