Journal of Nuclear Fuel Cycle and Waste Technology

Various kinds of RI wastes are discharged from licensed organizations of radioisotopes such as hospitals and clinic organizations, educational organizations, research institutions, and public organizations. Radioiodines such as 125I and 131I are radioisotopes mainly used in nuclear medicine and industry. A method for the determination of radioiodines in RI wastes has been applied to measure low level activity using acid decomposition method and HPGe gamma ray spectrometer. Prior to analysis of real samples, 131I reference solution and 10 g of yellow tissue paper was added to flask in mantle and was heated in 100 mL of 0.4 N K2Cr2O7 and 100 mL of 9 M H2SO4, and then distilled after adding 10 mL of 30 % H2PO3 and 1 mL of 30 % H2O2. The condensed iodine by circulator was extracted into CCl4, then back-extracted into the aqueous phase with 10 mL of 5 % K2SO2 solution. Finally, 131I was measured at 364.48 keV using HPGe gamma ray spectrometer after precipitation and filtration. Chemical yield of three steps such as acid decomposition process, chemical separation process, and precipitation and filtration process was more than 94 % respectively. MDA(Minimum Detectable Activity) of 131I at this analytical condition was 0.16 ßq/g.

Keywords

Acid decomposition method,Radioiodine,RI waste