Purpose: Complex stereotactic radiotherapy treatment plans require prior verification. A gel dosimetry system was developed and tested to serve as a high-resolution 3D dosimeter for Quality Assurance (QA) purposes.
Materials And Methods: A modified version of a polyacrylamide polymer gel dosimeter based on chemical response inhibition was employed.
The challenging issue of spent nuclear fuel (SNF) management is being tackled by developing advanced technologies that point to reduce environmental footprint, long-term radiotoxicity, volumes and residual heat of the final waste, and to increase the proliferation resistance. The advanced recycling strategy provides several promising processes for a safer reprocessing of SNF. Advanced hydrometallurgical processes can extract minor actinides directly from Plutonium and Uranium Reduction Extraction raffinate by using selective hydrophilic and lipophilic ligands.
View Article and Find Full Text PDFWithin a spent nuclear fuel recycling strategy, in the past few years, the pyridine-bis-triazole unit was found to be rather effective and selective in minor actinide (MA) separation from synthetic high active raffinate (HAR). In this research work, the main features of the recently studied ligand were investigated in order to evaluate its potentialities in SANEX-like processes. Its applicability in advanced separation processes was demonstrated, even at process temperatures.
View Article and Find Full Text PDFIn this communication, we report on the use of deep eutectic solvents (DESs) for processing nuclear waste, with a view to selectively recovering minor actinides (MA) from highly active raffinate solutions. DESs are an interesting new class of green and eco-sustainable solvents. Herein, a representative family of DES was tested as a co-solvent for MA/lanthanides partitioning based on Selective ActiNide EXtraction (SANEX)-like hydrometallurgical processes.
View Article and Find Full Text PDFThe free volume fraction of a macromolecular structure can be assessed theoretically by using a suitable model; however, it can also be evaluated from experimental data obtained from dilatometry and positron annihilation lifetime spectra. In this second case, a regular geometry of the sub-nanometric cavities forming the free volume has to be assumed, although in fact they are irregularly shaped. The most popular approach is to guess spherical holes, which implies an isotropic growth of these last with temperature.
View Article and Find Full Text PDFThe conformational isomerism of the chelating agent 2,6-bis(1-(3-hydroxypropyl)-1,2,3-triazol-4-yl)pyridine (PTD), exploited in fuel reprocessing in spent nuclear waste, has been studied by single crystal X-ray diffraction analysis in combination with an extensive DFT conformational investigation. In the solid-state, the elucidated crystal structure (, not yet published) shows that by thermal treatment (DSC) no other phases are observed upon crystallization from the melt, indicating that the conformation observed by X-ray data is rather stable. Mapping of intermolecular and intramolecular noncovalent interactions has been used to elucidate the unusual arrangement of the asymmetric unit.
View Article and Find Full Text PDFThe "CHON" compatible water-soluble ligand 3,3'-(pyridine-2,6-diylbis(1-1,2,3-triazole-4,1-diyl))bis(propan-1-ol) (PTD) has shown promise for selectively stripping actinide ions from an organic phase containing both actinide and lanthanide ions, by preferential complexation of the former. Aiming at improving its complexation properties, PTD-OMe was synthesized, bearing a methoxy group on the central pyridine ring, thus increasing its basicity and hence complexation strength. Unfortunately, solvent extraction experiments in the range of 0.
View Article and Find Full Text PDFThe radiological characterization of the topsoil of the L-54M reactor surroundings carried out in this work aims at obtaining the reference blank point for the forthcoming decommissioning operations and ascertain if unexpected radionuclide release occurred during the operational life of the plant. Standardised methods have been employed in order to collect representative samples and reliable results. Suitable sample pre-treatment procedures were applied.
View Article and Find Full Text PDFThe complexation of Cm(III) and Eu(III) with the novel i-SANEX complexing agent 2,6-bis[1-(propan-1-ol)-1,2,3-triazol-4-yl]pyridine (PTD) was studied by time-resolved laser fluorescence spectroscopy (TRLFS). The formation of 1:3, 1:2, and 1:1 metal/ligand complexes was identified upon increasing PTD concentration in 10 mol/L HClO and in 0.44 mol/L HNO solutions.
View Article and Find Full Text PDFThere is still an evident need for selective and stable ligands able to separate actinide(III) from lanthanide(III) metal ions in view of the treatment of the accumulated radioactive waste and of the recycling of minor actinides. We have herein demonstrated that hydrophilic 2,6-bis-triazolyl-pyridines are able to strip all actinides in all the different oxidation states from a diglycolamide-containing kerosene solution into an acidic aqueous phase. The ascertained high actinide selectivity, efficiency, extraction kinetics, and chemical/radiolytic stability spotlight this hydrophilic class of ligands as exceptional candidates for advanced separation processes fundamental for closing the nuclear fuel cycle and solving the environmental issues related to the management of existing nuclear waste.
View Article and Find Full Text PDFG Ital Med Lav Ergon
August 2011
Epidemiological data show excess of respiratory, dermatological, infectious, carcinogenic and musculoskeletal disorders among agricultural workers. Nevertheless, the national rates of reported cases do not correspond to the expected epidemiological data. In 2009, 3.
View Article and Find Full Text PDFEvaluating the chemical risks at the workplaces, the potential carcinogenic risk is a primary interest. Particularly, in the rubber forming industry the main attention was directed to the hot processing as a possible source of exposure to chemical agents, several of which were classified as carcinogens by the International Agency for Research on Cancer (IARC) and/or the European Union (EU). A study on occupational exposure to chemical carcinogens in the rubber forming industry was planned during last two years, involving a representative sample of firms.
View Article and Find Full Text PDFThis survey was carried out in the molding of plastics and rubbers, in the "Professional Cancer Prevention Project" sponsored by the Lombardy region with the objective of developing and implementing protocols for evaluating exposure to carcinogens through the biological monitoring. The realities of molding the thermoplastic polymer ABS, rubber, and thermosetting plastics containing formaldehyde were examined. The carcinogenic substances identified in these processes were: 1,3-butadiene, acrylonitrile and styrene in molding ABS, polycyclic aromatic hydrocarbons (PAH) in molding rubber, and formaldehyde in molding the thermosetting plastics.
View Article and Find Full Text PDFG Ital Med Lav Ergon
July 2008
Among various chemical agents present at the workplaces in the rubber industry, a particular attention was adressed to the Polycyclic Aromatic Hydrocarbons (PAH) contained in oil and carbon black, but some questions regarding level of exposure are also controversially discussed. The literature reports that PAH may have irritant effects; moreover some of these have been recognized as probably or possibly carcinogenic to human by the International Agency for Research on Cancer, the European Union, and other institutions. In Lombardy, a study aimed to evaluate the occupational exposure in Benzo[b]fluorantene the rubber forming industry was planned during last two years.
View Article and Find Full Text PDFEpidemiological studies conducted in the 1980s revealed that people working in the rubber manufacturing industry had an increased risk of cancer. Even now, workers employed in rubber processing are still at risk despite the measures adopted to improve their working conditions. The aim of the study was to evaluate the presence of a genotoxic risk in a rubber industry and to verify whether or not it was possible to locate the most dangerous position among the different rubber-working processes.
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