RAPID LEAKAGE SOURCE RECONSTRUCTION METHOD BASED ON BACKWARD ATMOSPHERIC DISPERSION SIMULATION

抄録

In recent years, cases of unknown leakage of radioactive materials have aroused more public concern and promoted the need for rapid leakage source reconstruction methods applied to estimate the source location and the release rate. In our work, we propose a source reconstruction method based on backward atmospheric dispersion simulation that is validated against the first European tracer experiment (ETEX-I). First, the source receptor sensitivity (SRS) matrix is calculated by the backward mode of the FLEXible PARTicle (FLEXPART) model, whose running times are equal to the number of measurements. Then our method reconstructs the source location and the release rate separately based on the SRS matrix, providing a way that can avoid the “overfitting” effect in the ill-posed minimization problem. The results demonstrate that our method can accurately reconstruct the source location at a low error level and retrieve the temporal profile of the release rate with the total release amount estimated within a 10% error level. In addition, we make a comparison between our method and a cost function method. The results indicate that our method has a great advantage in reconstruction efficiency since it does not need to traverse the entire computational domain. Finally, the sensitivity to the ratio threshold of SRS higher than 0 is also investigated. For the sake of the reconstruction accuracy and efficiency, the presented source reconstruction method here is potentially a practical tool for further integration into nuclear emergency response systems.