A radiochemistry laboratory exercise: determination of uranium in tap water by solvent extraction and liquid scintillation counting

Environmental radiochemistry is a key pillar of the education of nuclear engineering students and young professionals. Teaching the fundamentals of this multidisciplinary field is best performed also through well-designed hands-on experiments. A simple and fast radiochemical procedure has been developed to determine uranium in tap water by liquid scintillation counting. The proposed method provides reliable and repeatable results, with accuracy and precision within 5%. It can be proficiently executed by undergraduate students, who have appreciated the engagement and got acquainted with standard analysis protocols, from sample collection and manipulation to radiometric measure and data analysis

Physico chemical properties of irradiated i-SANEX diluents

The development of effective processes to recover minor actinides from spent nuclear fuel cannot leave out of consideration the evaluation of the impact of ionizing radiations on safety, fluid dynamics and extraction efficiency. It is common knowledge from the literature that radiation damage mainly affects the diluents and, indirectly, the extractants [1], but a lack of knowledge remains regarding the radiolytic behavior of innovative selective actinide extraction (i-SANEX) diluents [2, 3]. As natural prosecution of the work already performed on diluted nitric acid solutions [4], 0.44 M nitric acid solutions were irradiated in contact with a mixture of kerosene + 5 vol.% 1-octanol by a Co-60 source at 2.5 kGy/h dose rate and up to 100 kGy absorbed dose, conditions of interest for the future industrial facility. Density, viscosity, acidity, nitrate anion concentration and phase transfers were systematically measured before and after γ-irradiation. This was performed because radiation-induced modifi cations of these parameters may induce alterations of both the fluid dynamics and the separation performances of the extracting system. The results suggest that the fluid-dynamics of the system should be unaltered. In fact, only slight alterations of the organic phase viscosity and of the aqueous phase acidity were measured after irradiation, suggesting the occurrence of limited phase transfers and of diluent by-products formation

Pre-impregnation approach to encapsulate radioactive liquid organic waste in geopolymer

The pre-disposal management of Radioactive Liquid Organic Waste (RLOW) is hampered by its challenging physico-chemical properties. In this work, a straightforward conditioning option based on RLOW impregnation on absorbing materials and followed by encapsulation in a stable geopolymeric matrix is proposed, avoiding onerous pre-treatments and the use of surfactants. Recycled materials have been investigated as adsorbent and geopolymer precursors to foster process sustainability. Relevant properties have been studied to ascertain the waste acceptance criteria accomplishment: materials compatibility, RLOW loading factor and bleeding, microstructure, compressive strength, leaching and thermal stability. This approach is promising, although some criticalities remain unsolved

Comparison of site sensitivity of crop models using spatially variable field data from Precision Agriculture

Site conditions and soil properties have a strong influence on impacts of climate change on crop production. Vulnerability of crop production to changing climate conditions is highly determined by the ability of the site to buffer periods of adverse climatic situations like water scarcity or excessive rainfall.  Therefore, the capability of models to reflect crop responses and water and nutrient dynamics under different site conditions is essential to assess climate impact even on a regional scale. To test and improve sensitivity of models to various site properties such as soil variability and hydrological boundary conditions, spatial variable data sets from precision farming of two fields in Germany and Italy were provided to modellers. For the German 20 ha field soil and management data for 60 grid points for 3 years (2 years wheat, 1 year triticale) were provided. For the Italian field (12 ha) information for 100 grid points were available for three growing seasons of durum wheat. Modellers were asked to run their models using a) the model specific procedure to estimate soil hydraulic properties from texture using their standard procedure and use in step b) fixed values for field capacity and wilting point derived from soil taxonomy. Only the phenology and crop yield of one grid point provided for a basic calibration. In step c) information for all grid points of the first year (yield, soil water and mineral N content for Germany, yield, biomass and LAI for Italy) were provided. First results of five out of twelve participating models are compared against measured state variables analysing their site specific response and consistency across crop and soil variables.(Main text to be published in a peer-reviewed journal

Comparison of site sensitivity of crop models using spatially variable field data from Precision Agriculture

Site conditions and soil properties have a strong influence on impacts of climate change on crop production. Vulnerability of crop production to changing climate conditions is highly determined by the ability of the site to buffer periods of adverse climatic situations like water scarcity or excessive rainfall.  Therefore, the capability of models to reflect crop responses and water and nutrient dynamics under different site conditions is essential to assess climate impact even on a regional scale. To test and improve sensitivity of models to various site properties such as soil variability and hydrological boundary conditions, spatial variable data sets from precision farming of two fields in Germany and Italy were provided to modellers. For the German 20 ha field soil and management data for 60 grid points for 3 years (2 years wheat, 1 year triticale) were provided. For the Italian field (12 ha) information for 100 grid points were available for three growing seasons of durum wheat. Modellers were asked to run their models using a) the model specific procedure to estimate soil hydraulic properties from texture using their standard procedure and use in step b) fixed values for field capacity and wilting point derived from soil taxonomy. Only the phenology and crop yield of one grid point provided for a basic calibration. In step c) information for all grid points of the first year (yield, soil water and mineral N content for Germany, yield, biomass and LAI for Italy) were provided. First results of five out of twelve participating models are compared against measured state variables analysing their site specific response and consistency across crop and soil variables.(Main text to be published in a peer-reviewed journal

Tra erudizione e filologia: Jacopo Bernardi dantista

Il contributo si occupa degli studi danteschi (testuali e no) di Jacopo Bernardi, sodale di Niccolò Tommaseo e colezionista di memorie della storia letteraria italiana