Characteristics of radioactive aerosols during the pre-decommission phase of the experimental shielding reactor

Abstract

The decommissioning of nuclear reactors is a global concern, in part because of the generation of radioactive aerosols that can lead to internal radiation exposure. At present, radioactive aerosols generated during nuclear decommissioning have not been actively studied, and data collected from the actual decommissioning are limited. This paper presents a study of radioactive aerosols generated during the pre-decommission phase of an experimental shielding reactor. Among all the on-site operations, cutting resulted in the highest levels of radioactivity. Plasma arc cutting, in particular, had a maximum gross α and β radioactivity over 0.10 and 0.14Bq/m3, respectively. Assumed AMAD (activity median aerodynamic diameter) values are employed to assess the impact of particle size on the internal exposure dose resulting from the inhalation of 137Cs aerosols based on the Human Respiratory Tract Model of International Commission on Radiological Protection. When cutting stainless steel by plasma arc, the internal exposure dose caused by 137Cs aerosols with an AMAD of 0.1 μm is estimated to be nearly four times as that of aerosols with an AMAD of 10 μm. Results show that the internal exposure dose is highly dependent on the AMAD, implying the importance of measuring size-related parameters of radioactive aerosols in the future nuclear decommissioning. This study has revealed some characteristics of radioactive aerosols released in decommissioning operations, which can serve as a valuable reference for controlling and removing aerosols during the decommissioning of nuclear facilities. Environmental ImplicationThis paper presents a study of radioactive aerosols generated from the pre-decommission phase of an experimental shielding reactor. When inhaled, the radioactive aerosols may deposit in the respiratory tract and lead to internal radiation exposure, posing a threat to the safety of on-site workers and the surrounding environment. The results of this study contribute to provide guidance on radioprotective countermeasures for on-site workers. It can serve as a valuable reference for the control and removal of radioactive aerosols during the decommissioning of nuclear facilities, as well as an impact assessment of the decommissioning on the environment and public safety.