The effect of using Filtered Containment Venting System on variation in dose with distance in the prompt accident consequence assessment

Abstract

ABSTRACT In a nuclear emergency, consequence assessment based on the plant conditions using a simple method is important for a prompt response. Response Technical Manual (RTM-96) is a manual calculation method for prompt dose projection at arbitrary distances by converting pre-calculated doses with the conversion factor based on distance and weather. However, the ‘conversion factor’ in RTM-96 does not consider accident scenarios with filtered containment venting system (FCVS). Therefore, in this study, we defined the ratio of effective dose between 1 km and an arbitrary distance as the ‘Distance Conversion Factor (DCF)’ and aimed to clarify the difference between DCFs by accident scenarios, focusing on the presence or absence of FCVS. The results showed that the differences in DCFs for different accident scenarios were minor in the case of no rainfall. In contrast, in the case of rainfall, DCF differed significantly with scenarios with FCVS and those with containment failure. Therefore, the authors propose that DCFs with rainfall should be calculated separately for several representative accident scenarios rather than uniformly for all accident scenarios, as in the conventional method. The results can contribute to developing a new prompt consequence assessment method, such as RTM-96, which considers FCVS.