SOLID-PHASE EXTRACTION FOR THE SEPARATION OF ACTINIDES FROM RADIOACTIVE WASTE

摘要

For the characterisation of conditioned radioactive waste, the actinides to be analysed must be separated from matrix components, if possible, element-specific. Microwave pressure digestion is a time -saving digestion method for radioactive waste samples. The partitioning of the actinides from the liquid samples are carried out with the aid of solid -phase extraction. For the experiments, on the one hand, commercially available extraction resins such as Actinide ™, TRU™, UTEVA ™ and TEVA™ Resin from Eichrom were used. On the other hand, an extraction resin with Cyanex 301 produced in- house was tested specifically for actinidelanthanide partitioning. It was possible to separate 99.4 % of the lanthanides by a two-stage partitioning process. A partitioning run using the Eichrom resins was successfully adapted to the waste matrices and automated with the aid of a laboratory robot. It is particularly meaningful to perform a prior matrix partitioning with Actinide™ Resin A semi-quantitative qualification of the sample is possible by the α-analysis of the actinide fraction. The extractant, which was eluted from the column together with the actinides, was destroyed oxidatively by means of a newly developed technique using microwave pressure digestion.