Development of PSkits for fast and selective analysis of 99Tc.

Abstract

The dismantling of nuclear plants will experience an increase in the following years around Europe and it will require a great number of radioactive residues analysis that may imply significant economic cost. For this reason, the obtention of fast and selective identification methods for alpha and beta emitters in liquid samples is a topic of interest for the future. The aim of this project has been to design a fast and selective method for characterization of beta radionuclides by using plastic scintillator foils that, with the addition of a selective extractant, generate what is known as PSkits. Specifically, the study has been focused on the detection of 99Tc, an important residue from nuclear power plants. The synthesis of porous foils of polystyrene with fluorescent solutes has been studied in a polymerization process. Different experimental conditions have been studied in order to ensure porosity and fastening of the foils to the scintillation vials where they are prepared. In addition, with the use of a selective extractant for technetium as a recovering, the selective PSkits applicable to liquid samples have been generated. From the results, it has been seen that the purification of the monomers reduced the interference phenomenon in the scintillation process. In addition, the presence of DVB increased the rigidity of the foil and gave stability without modifying the scintillation capacity. Furthermore, heptane has been proved as an acceptable porogen and both plastic and glass scintillation vials presented selective retention capacities over 95%. Detection efficiencies in glass vials were around 20%, whereas plastic vials were rounding 50-60%, being the last mentioned the ones with better results. It can be concluded that the developed method, based on foils, has been satisfactory for the detection of beta emitters, although it will require an extensive optimization work to ensure robustness