Investigation of Activity Concentrations of NORMs for Industrial Use in Japan

Natural radioactive nuclides are contained in natural materials, namely, ores, rocks and oils. These materials are frequently used as industrial raw materials. If these materials contain natural radioactive nuclides in high concentration, workers can be exposed to radiation at a serious level. Therefore, it is important to investigate the activities in these materials. In this study, natural materials which are actually used as industrial raw materials were collected and the activities in them were determined using ICP-MS and gamma ray spectrometry. The activities of 238U series, 232Th series and 40K in these materials were lower than values suggested in RS-G-1.7