Analysis of the suitability of atmospheric dispersion models used under normal operational and accident conditions of NPPs

Atmospheric dispersion modeling is a critical component of the systems for NPP dose assessment under normal operational condition and nuclear accident consequence assessment. It determines the accuracy of dose assessment results and the environmental risk of potential accidents of an NPP. It also directly impacts a decision making process against a nuclear emergency. In this paper, representative national and foreign atmospheric dispersion models used for dose assessment under normal operational condition, and for probability risk assessment and real-time consequence assessment are reviewed. The characteristics, meteorological inputs, and suitability of various models are compared and analyzed. Problems that should be considered in application are indicated. The future prospects of atmospheric dispersion models are discussed. The results indicate that Gaussian-plume models can be used under spatially uniform wind field, windy conditions and for local scale dispersion. However, other appropriate models should be applied when the terrain is complex, the dispersion range is long, or the wind is calm or light. For the aspect of probability risk assessment, a diversity of atmospheric dispersion models should be developed. For real-time consequence assessment, the accuracy of meteorological forecasts is of particular concern. Nested atmospheric dispersion models of multi-scales should be developed, and model validation should be enhanced. In practical application, a balance between the model complexity, running cost, and the accuracy of modeling results should be taken into account. (authors)