Tc Generator Development: Up-to-Date Tc Recovery Technologies for Increasing the Effectiveness of M o Utilisation

A review on the Mo sources available today and on the Tc generators developed up to date for increasing the effectiveness of Mo utilisation is performed in the format of detailed description of the features and technical performance of the technological groups of the Mo production and Tc recovery. The latest results of the endeavour in this field are also surveyed in regard of the technical solution for overcoming the shortage of Mo supply. The technological topics are grouped and discussed in a way to reflect the similarity in the technological process of each group. The following groups are included in this review which are high specific activity Mo : the current issues of production, the efforts of more effective utilisation, and the high specific activity Mo -based Tc generator and Tc concentration units; low specific activity Mo : the Mo production based on neutron capture and accelerators and the direct production of Tc and the methods of increasing the specific activity of Mo using Szilard-Chalmers reaction and high electric power isotopic separator; up-to-date technologies of Tc recovery from low specific activity Mo : the solvent extraction-based Tc generator, the sublimation methods for Mo / Tc separation, the electrochemical method for Tc recovery, and the column chromatographic methods for Tc recovery. Besides the traditional Tc -generator systems, the integrated Tc generator systems ( Tc generator column combined with postelution purification/concentration unit) are discussed with the format of process diagram and picture of real generator systems. These systems are the technetium selective sorbent column-based generators, the high Mo-loading capacity column-based integrated Tc generator systems which include the saline-eluted generator systems, and the nonsaline aqueous and organic solvent eluent-eluted generator systems using high Mo-loading capacity molybdategel and recently developed sorbent columns. Tc concentration methods used in the Tc recovery from low specific activity Mo are also discussed with detailed process diagrams which are surveyed in two groups for Tc concentration from the saline and nonsaline Tc -eluates. The evaluation methods for the performance of Tc -recovery/concentration process and for the Tc -elution capability versus Mo-loading capacity of generator column produced using low specific activity Mo source are briefly reported. Together with the theoretical aspects of Tc / Mo and sorbent chemistry, these evaluation/as