A Staged Evacuation Methodology for Emergency Preparedness Plan

Abstract

ABSTRACT Early public protection measures play an important role in reducing the health effects of radiation exposure. In particular, a staged evacuation is recognized as the most important strategy. However, studies on segmenting an evacuation region with non-uniform population density are lacking; therefore, the purpose of this study is to gain insight regarding this topic. First, the evacuation region was determined by comparing the level 3 probabilistic safety assessment (PSA) results with the generic-dose limit. Second, we performed mathematical approaches to calculate the evacuation and delay time. We then scored staged evacuation strategies and selected the best strategy. Through this study, we found some features as follows: (1) the evacuation and delay time have a trade-off relationship, (2) there is no significant difference in total evacuation time except for the preparation time, and (3) there is a big difference in total delay time despite the same segmentations. Namely, even if the evacuation time may be the same, the delay time may differ. The delay time can be defined as the period that people spend on the road, and so the longer the delay time, there is an increased likelihood of receiving unnecessary exposure.