Study on estimation of evacuation distances for nuclear emergency

Sato, Sohei; Umemoto, Michitaka*; Homma, Toshimitsu

JAERI has conducted the analytical studies on the PSA, the severe accidents, and the optimization of protective actions. Based on the results of these studies, JAERI is investigating the method for taking urgent protective actions more reasonably. If an accident occurs in a NPP, early protective actions are carried out. To implement these actions more effectively, emergency preparedness and emergency planning are important, and especially prompt evacuation is expected to reduce a large amount of radiation exposures. To examine the effect of early protective measures by using a PSA method, estimation of the parameter uncertainty related in the time for early protective actions is needed. For this purpose, we have developed an analytical method for urgent protective actions, and estimated the movement distance. This report provides a brief description of the method for estimating the movement distance, input data for this analysis, and the result. Moreover, the problem on the method of evacuation distance analysis and usefulness of this method for emergency planning were discussed.