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  • Author or Editor: J.H. Chao x
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Abstract  

An approach based on sequential extraction separation and the subsequent ICP-MS measurement was introduced to determine 99Tc in radioactive wastes. The radwastes were firstly alkaline-fused and the 99Tc was separated by a sequential solvent extraction prior to ICP-MS measurement. NaDDC was selected as a chelation reagent in the solvent extraction processes. The influence of HCl and matrix concentration on the recovery yield and the effectiveness of removing isobar and unwanted radionuclides, such as 137Cs, 54Mn, 60Co and 110mAg, were evaluated. The designed sequential extraction procedure was optimized by an extraction experiment. The proposed technique is proven to be a simple and practical alternative for 99Tc determination in low-level radioactive wastes; chemical separation of 99Tc can be simplified and preconcentration such as precipitation and/or ion exchange, before the solvent extraction, can be excluded.

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Abstract  

Evaluation of minimal detectable amounts (MDA) of iodine in various or specified irradiation and measurement conditions is described. Interfering contributions due to Na and Cl to the spectral background as well as the dead time of detection system were calculated in details based on an experimental approach. The MDA of iodine for some important biological samples with various Na and Cl concentrations can be evaluated and predicted according to the specified irradiation and measurement arrangements to meet the requirement of analytical purposes.

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Summary  

Exploratory experiments have been carried out to investigate the effects of gamma-radiation on iodine aerosols under various chemical conditions. The results indicate that iodide ions (I-) in aerosol can be readily oxidized to I2 and HIO, and some iodide ions may be converted to organic iodine when organic additives are present in the KI solution from which the aerosol is generated. The results also suggest that the chemical transformation of irradiated iodine aerosol depends on the chemical environment both carrier gas and iodide solution.

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