Verification of the Lagrangian particle model using the ETEX experiment

A Lagrangian particle model named LADAS (Long-range Accident Dose Assessment System) has been developed to understand the characteristics of the long-range transport and diffusion of a radioactive material released into the atmosphere. The developed numerical model was compared with the results of European Tracer Experiment (ETEX) which is a long-range field tracer experiment. Several simulations were performed to investigate the effects according to the variation of the mixing height. As a comparative study, the calculated concentration distributions agreed well in the case of the usage of the mixing height calculated by the Richardson number than the usage of the constant mixing height in the computational domain. The calculated particle cloud represented well the phenomenon that was transported north-westerly from a release point such as the ETEX results.