Level 3 PSA(Probabilistic Safety Assessment) concerns the dispersion and effects of a radioactive release resulting from an accident at a nuclear power plant. It is often called a consequence analysis. Consequences result from the radioactive material released in a severe accident. Level 3 PSA estimates those consequences such as health effects such as short-term injuries or long-term cancers. The health effects depend on the population in the plant vicinity, evacuation conditions, and weather conditions. In the early stage of the accident, there are public protection measures such as sheltering and evacuation. There are many factors affecting the early protection measures. Hence, the early protection measures considering these factors should be assessed for setting the emergency response model in Level 3 PSA. It is called analysis of ETE(Evacuation Time Estimate). ETE is to calculate the time to evacuate the plume exposure pathway EPZ(Emergency Planning Zone). The purpose of ETE is to provide a tool for preplanning protective action decision making and inputs for constructing the emergency response model. However, the emergency response model has considerable uncertainties and huge impact on consequence results. Therefore, ETE analysis is very important to reduce the uncertainty of Level 3 PSA. However, ETE analysis was not performed properly in Korea. Therefore, the purposes of this study are to perform ETE analysis, concern the uncertainty factors and suggest the way to reduce uncertainties.