SOURCE TERM ESTIMATION BASED ON ENVIRONMENTAL RADIATION DATA IN QINSHAN NUCLEAR POWER PLANT OF CHINA

Achieving information of source terms is an import task in emergency response during a nuclear accident. Affected by large errors of atmospheric model, the reverse modeling of atmospheric dispersion faces great challenges. The traditional scaling method adopted in Fukushima nuclear accident is affected by deviation of the observed and predicted values. To cope with the deviations, an assimilation model based on Ensemble Kalman filter (EnKF) was established with consideration of model errors and observation errors. It was validated by 7 groups of tracer experiments. The result shows that the EnKF model could estimate the release rate of source term successfully. This scheme was applied to emergency response system of Qinshan nuclear power plant. Keyword: atmospheric dispersion, source term estimation, nuclear accident