Sequential determination of 99Tc and 126Sn in radioactive concentrate

This paper describes a new sequential method using anion exchange resin, which is commercially available from Eichrom Technologies, Inc., for the determination of Tc-99 and Sn-126 in nuclear waste samples. For the determination of non-actinide radionuclides in radioactive wastes, several methods have been recently introduced. This method is suitable for the separation of radionuclides Tc-99 and Sn-126 from acidic solutions. Samples after digestion were directly loaded in 2 mol.dm(-3) HCl acid on a cation exchange resin and then on an anion exchange. They were eluted with HNO3. After elution, the eluted fractions were measured either by gamma spectrometry on an HPGe detector or liquid scintillation counter with high chemical recoveries for a short period of time. Activity concentrations of Sn-126 were below minimum detectable activity (MDA) for each experiment. A new radioanalytical method for the sequential determination of Tc-99 and Sn-126 in radioactive concentrates has been developed and successfully applied. The main advantage of the method was the time required for the separation of radionuclides, which was only five hours, and single column separation for the determination of these radionuclides, which makes the method very effective and cheap.