Evaluation of the ~(14)C release characteristics of a reactor building using high-compression collection equipment in Korean pressurized water reactors

摘要

In general, most nuclear power plants (NPPs) have one exhaust duct. However, each Korean NPPs specifically equip four exhaust ducts that release gas into the environment. Thus, Korean NPPs have difficulty in managing the radioactive effluents. The gas from the reactor building at a nuclear power plant is released into the environment through an exhaust system while fresh air is supplied into the building at the same time to satisfy the access conditions of the reactor building. It is important to secure measurable samples while the emission is in progress for reliable measurements of ~(14)C in the effluent gas from the reactor building and for reliable assessments of the radiation exposure dose to residents who live in the area. The emission from the reactor building is done in a batch-wise manner in a limited time. It is difficult to measure ~(14)C with conventional gaseous ~(14)C collection equipment due to the typically small sampling volume of this type of equipment. To address this problem, a device was developed that can highly compress and store gas released over a short time in a tank that can be connected to gaseous ~(14)C collection equipment for later analysis. This device was successfully used to capture samples to assess the characteristics of the ~(14)C emissions from a reactor building. In this paper, a high-compression sampling device developed for the analysis of ~(14)C from a reactor building is introduced and the result of an assessment of the characteristics of ~(14)C emission from the reactor building with this device is discussed.