Simultaneous determination of radioactive halogen isotopes and 99Tc

The purpose of this study was to develop a simplified method for simultaneous determination of radiologically important halogen isotopes and Tc-99 from different types of samples like environmental, biological and waste samples. Due to their long half-lives (longer than 10(5) years) they play important role in the nuclear cycle, especially in environmental monitoring and protection. For a rapid response in the evaluation of I-129, Cl-36 and Tc-99 contamination levels of these samples it is advantageous to combine the existing individual methods. According to the present procedure, iodine, chlorine and technetium are separated selectively from the same sample aliquot followed by the B-spectrometry of the purified fractions. Increased sensitivities can be achieved by neutron activation (NA) especially in the case of I-129. Our work intends to solve the problem by combining the well-known hot acidic distillation method for iodine separation with the organic extraction process characteristic for technetium separation. The major objective of the work was to separate the disturbing halides from iodine. For this purpose a selective oxidant was applied. For the sample destruction and fractionated distillation an air flow-through installation was used with hot concentrated sulphuric and nitric acids. The trap for iodine contained 3 M NaOH solution. After iodine separation the trap was exchanged for a new one containing the same solution for trapping chlorine or bromine with an addition of 0.01 M KMnO4 solution as an oxidative agent. As expected, the main part of technetium was contained in the acidic residue after distillation. Tc purification was performed by organic extraction with TBP and TEVA column.