QUALITY CONTROL FOR THE ANALYSIS OF RADIONUCLIDE IN RADIOACTIVE WASTE OF KOREA NPPS

摘要

Various types of radioactive waste are discharged from a nuclear power plant (NPP). The type and concentration of the radionuclide differ from each other according to the specifications of the radioactive wastes. Since most nuclides in radioactive wastes are trace amounts, the quality control of an analytical procedure is important to measure the radionuclide accurately. In this study, relating to the analysis of radionuclides in the radioactive wastes of the NPPs in Korea, the results of the quality control of a sample preparation, analysis of the fission products and volatile nuclides, and the radiation counting systems were investigated. Validity of the applied analysis methods of the radionuclide in radioactive waste was confirmed by the reliability of the measured results of standard materials. We also selected different detectors for the analysis of the radionuclides, and composed proper counting systems. The stability of the radiation counting systems were evaluated by a periodic measurement of the background value and the counting efficiencies of the systems, and by drawing up a chart of the quality control. The data of the background values and the counting efficiencies were applied to evaluate the minimum detectable activity (MDA) of the radiation counting systems for each radionuclide. The MDAs for the gamma-ray spectrometer and the liquid scintillation counting (LSC) system were calculated as 3.2 Bq/mL and 3.8 Bq/mL, respectively. The MDAs of the alpha/beta counting system in the alpha and beta range were 20.5 Bq/mL and 23.0 Bq/mL, respectively.