Assessment of Radiation Dose to Workers Resulting from External Exposure to Potassium in NORM Industries in Korea

Potassium is a naturally-occurring radioactive material (NORM). Potassium contains 40 K, a natural radionuclide that may enhance the radiation dose to workers in potassium processing facilities. The objective of the present study is to assess radiation dose to workers resulting from external exposure to potassium in NORM industries in Korea. Five potassium processing facilities were selected for this dose assessment study. Initial dose rate mapping was made through the whole facility site for scanning purposes. Based on an analysis of the initial dose rate mapping and potassium processing, the areas requiring more detailed dose rate measurements were selected. Target workers for radiation dose assessment were selected based on the second step dose rate mapping results and specific working conditions. The annual radiation dose to the target workers was assessed using the measured dose rates and hypothetical exposure scenarios. Annual radiation dose to the workers resulting from external exposure to potassium ranged between 0.003 - 0.364 mSv/yr. The results of the present study can be used to better protect workers handling naturally-occurring radioactive materials.