The phosphate industry is classified by IAEA as one of the Naturally Occurring Radioactive Materials (NORM) industry sectors most likely to require regulatory consideration. The production of phosphorous fertilizers constitutes the major activity in the industry, which can give rise to exposures of workers and the public through the handling and usage of phosphate rock and residues associated with processing. During the production process, when phosphate rock is digested with acid to produce phosphoric acid, some radionuclides, particularly Radium, become concentrated in residues, such as the scale that tends to form inside pipes and vessels. The registered radioactivity of phosphate rock in South Korea is less than 1.7 Bq/g for U-238, but according to the IAEA SRS No. 49, the radioactivity of phosphate scale can be up to 1,000 times higher than the raw mineral. Therefore, this study evaluated the potential for worker exposure during maintenance related to the removal of scales at a fertilizer manufacturing facility producing phosphoric acid in Korea.

• Zu-Hee Woo(Korea Institute of Nuclear Safety (KINS)) Corresponding author
• Jung-Hwan Jang(Korea Institute of Nuclear Safety (KINS))
• Han-Chang Seo(Korea Institute of Nuclear Safety (KINS))
• Byung-Uck Chang(Korea Institute of Nuclear Safety (KINS))