Development of a source term estimation method for nuclear emergency by long-range atmospheric dispersion simulations

Furuno, Akiko   ; Chino, Masamichi; Yamazawa, Hiromi*

This paper describes a method of estimating source term, i.e., location, period and amount of atmospheric release of radioactive material in real-time during nuclear emergency. This method consists of: (1) trial simulations of atmospheric dispersions on the possible combinations of these parameters and (2) statistical comparison of model predictions with off-site measurements of air concentrations of radionuclides and/or air does rates from monitoring stations, to find a set of release condition providing model predictions that best fit to the measurement. A parallel execution method for efficiently processing many possible initial conditions is also developed. The performance of this method is favorably evaluated by a verification study by using the dataset from European Tracer Experiment.