Abstract: The short-term atmospheric dispersion factors under four different classification methods of atmospheric stability were calculated by using PAVAN program, and the dose at the boundary of exclusion area (500 m) and planning restricted area (5 km) under the postulated siting accident was calculated. The result shows that the value of the short-term atmospheric dispersion factor under the Richardson number method is the smallest, while the value under the ΔT/U method is the largest. The value of the maximum individual effective dose on the exclusion area boundary (2 hour after the accident) and value at the planning restricted area boundary during the postulated siting accident satisfied the requirement of GB 6249, and the value of the dose was also the smallest under the Richardson number method, the largest under the ΔT/U method. The maximum value is about 1.6 times the minimum value. For the environmental impact assessment, it should be paid more attention to the influence of different atmospheric stability classification method on the dose evaluation of postulated siting accident.

Key words: atmospheric stability, short-term atmospheric dispersion factor, postulated siting accident, dose