Titolo della tesi: Development of radiochemical methods for the radiometric characterization of natural and anthropogenic matrices
The analysis of radionuclides in NORM (Naturally Occurring Radioactive Materials) samples is crucial for several reasons, such as health and safety, regulatory compliance, environmental protection, risk assessment, waste management, public awareness, long-term monitoring, research and development.
Overall, analysing radionuclides in NORM samples is vital for ensuring safety, compliance, and environmental protection.
Depending on the site considered, NORM samples may be different and, when required, a prompt response to the problem should be given.
The aim of this work is to develop different methods in order to be able to analyse simultaneously different radionuclides in different matrixes of solid NORM samples.
210Po, 210Pb, uranium and thorium isotopes were considered in the study with the aim of developing a radiochemical strategy for their simultaneous analysis in solid samples. The research work carried out in the thesis was therefore focused on addressing all the critical issues that currently represent an obstacle for the simultaneous determination of radionuclides in general, and of those chosen for the study in particular. Indeed, the development of such a procedure involves the optimization of different steps, all of which presenting several problems, when dealing with multiple radionuclides: 1) dissolution; 2) purification; 3) separation; 4) source preparation; 5) acquisition. Across the research period, all these steps have been optimized, considering the challenges posed by different sample matrixes, as evaluated through the analysis of three certified reference materials: IAEA-434 (phosphogypsum), IAEA-312 (soil) and IAEA-S-17 (mineral).
The results obtained show that the proposed work has a good versatility of application and may be used flexibly depending on the solid matrix considered allows a prompt response to the problem under investigation.
In addition, the optimisation of individual steps allows for very low analytical cost due to using only two resins and the usually tedious sample dissolution were performed only once for all the radionuclides investigated.