Study on the effects of topography on atmospheric dispersion

A real-time atmospheric dispersion and dose assessment system FADAS has been developed. It has been used as a basic tool for providing the function of the atmospheric dispersion of released radioactive materials and the radiological dose assessment to the national emergency preparedness system CARE since 1995. Large-scale field tracer experiments have been conducted for the purpose of validating FADAS and of analyzing the environmental characteristics around nuclear sites since 1994. Field tracer experiments have been performed using the automatic sequential samplers over nuclear sites. The measured concentration distributions were compared with those simulated by FADAS. Both concentration distributions agreed well in the distribution pattern