Applicability of 100 TBq cesium 137 release into environment as a safety criterion for consequence assessment at reactor design approval stage

Abstract

The International Atomic Energy Agency (IAEA) fundamental safety objective is to protect people and the environment from harmful effects of ionizing radiation. Therefore, a severe accident consequence assessment has to be able to include all quantifiable consequences on people and the environment. Our previous studies on estimation of cost per severe accident succeeded in quantifying aforementioned consequences. However, the estimation requires enormous quantity of data, time and human resources, thus it may be inappropriate at the reactor design approval stage. Finnish government uses “100 TBq cesium 137 release into environment”, which was proved to generate limited health effects, as one of the reactor design criteria for accident consequences. In this study, we perform an evaluation of annual dose from the 100 TBq cesium 137 release and confirm limited health effects. We form the environmental impact index based on insights from our previous studies and used it to assess consequences to the environment. The estimated environmental impact index is very small, which confirms the limitedness of the environmental impacts of the release. These findings ensure the applicability of 100 TBq cesium 137 release into environment as a safety criterion for consequence assessment at reactor design approval stage.