[en] The work aims to find a viable alternative to the treatment of wastewater containing uranium in its composition, aiming to help predict the physical and chemical characteristics suitable for the production of polymeric ion exchange resin that will act in the adsorption of the contaminant. The PHREEQC software was used to predict uranium speciation under simulation conditions based on experimental data obtained in previous studies, using material collected in a deactivated uranium mine located southwest of Salamanca, Spain

[en] n this work, the objective was to characterize materials from the volcanic region, named RT17 and RT22, which have proven to be efficient as flocculants, both being provided by IQR Indústria Química and already used by the company itself in decontamination applications. It is important to highlight that flocculation is a step that favors the treatment of mining effluents [5], as, through the aggregation of compounds suspended in the fluid, it facilitates the treatment of these effluents. The motivation for using the proposed techniques - DRX and FRX - consists of predicting whether the materials under study may present advantages for use as adsorbents, allowing not only to act as flocculants, but also to recover radionuclides in mining regions, by adsorption, ion exchange or combination of both

[en] The safety analysis of nuclear installations is a crucial point in the design and maintenance of nuclear installations. In this sense, the curricular discipline of Safety of Nuclear Installations offered by the Postgraduate Program in Nuclear Science and Technology (PCTN/UFMG), proposes to present a broad view of the safety systems involved in installations in general, focusing on the mechanisms of reactor safety. To improve the knowledge involving unwanted events in plants, it was proposed to carry out a project base accident without the application of countermeasures. From a PWR (Pressurized Water Reactor) model from Angra 2 developed for the RELAP5/MOD3.3 and RELAP-3D codes, two cases of loss of flow accident (LOFA) were studied, based on the nodalization previously developed at the Department of Nuclear Engineering (UFMG/ DEN). The first step consisted of verifying the nodalization in steady state. The values found were compared with the constants in the FSAR (Final Safety Analysis Report) and the error found are that are within the values accepted by RELAP users. Subsequently, the operational transient accident of a pump stop was studied, called Case A, and the stoppage accident of two pumps, called Case B. The results showed that the nodalization of Angra 2 in steady state is representative, showing that computer simulation can be used as a tool to evaluate cases of accidents in nuclear reactors. The analysis of cases A and B showed that the accidents cause disturbances in the system, such as an increase in temperature in the reactor and the formation of voids in the system of the thermal hydraulic channels for case B. (author)

[en] A polymer-based composite material was developed for use as a yes/no indicator of the high-doses gamma irradiation process. It was prepared with glycerin, gelatin, formaldehyde, clinical gel and copper sulfate pentahydrate (0.1% in relation to the total mass of the composite). Copper sulfate was intended as a chemical indicator of radiation exposure, with mechanisms focused on the processes of interaction with radiation. The formation of copper oxide and sulfur compounds was predicted, which would result in a color change, since CuSO₄.5H₂O confers a blue coloration to the composite. To evaluate the role of copper sulfate in the production of a chemical indicator of radiation exposure, a sample without CuSO₄.5H₂O was also prepared. The samples were irradiated with doses of 50, 80 and 100 kGy of gamma radiation from a Cobalt-60 source, in the Gamma Irradiation Laboratory of the Nuclear Technology Development Center, which has a multipurpose panoramic irradiator. The samples were characterized by Fourier-transform infrared spectroscopy (Ftir), demonstrating their glycerin-based composition. To evaluate the color variation in the irradiated and non-irradiated samples, they were photographed and analyzed using the color catalog of the Adobe Color® application. The sample with CuSO₄.5H₂O showed significant color variation after irradiation, ranging from shades of blue to red/brown. The results demonstrate the potential of polymer composite whit sulfate pentahydrate for use as yes/no indicators of the irradiation process. It encourages future work to evaluate the composite for dosimetry purposes. (author)

[en] Starch is a polysaccharide formed by the union of α-glucose molecules of amylose and amylopectin, and is stored in different plant organs. It has been used as an important ingredient in the food and non-food industries, with diverse applications due to its low cost and biodegradability. To expand its use, modifications to natural starch have been studied to make it suitable for each specific application. A processing technique that can be used to modify materials is exposure to high doses of gamma radiation. Starch has already been subjected to gamma irradiation in previous studies, but usually at low doses (below 100 kGy). In order to increase knowledge about the effect of gamma radiation on starch structure, samples of natural starch (Starch), waxy starch (WX) and cationic waxy starch (WX Cat) were irradiated with 500 kGy. The samples were irradiated in the Gamma Irradiation Laboratory of the Center for the Development of Nuclear Technology (CDTN), which has a panoramic irradiator equipped with a Cobalt-60 source. The materials were evaluated before and after irradiation through the techniques of Fourier-transform infrared spectroscopy (Ftir), Scanning electron microscope (Sem) and thermal gravimetric analysis (TGA). Lugol's iodine test was performed to qualitatively evaluate the relationship between amylose and amylopectin in the samples. The Ftir made it possible to characterize and compare the starches studied. Sem analysis demonstrated the effects of irradiation on starch morphology. The TGA results indicate an increase in residue in the irradiated samples, which may be related to the formation of radiation-induced cross-links. Lugol's iodine test showed that the prevalence of amylopectin in the composition of waxy starches was maintained. (author)

[en] The understanding of the biogeochemical processes in which trace metals participate in mine regions requires the determination of the different physico-chemical species of the metals present. In the case of uranium extraction mines, the concern is focused on the efficiency of separating other elements present with similar chemical behavior. Added to this are the issues of radioprotection associated with the leaching process and mine acidity. Molybdenum is a trace element present in some uranium-rich regions. The challenge of separating the two elements is presented, reflected in the uranium enrichment process as a subsequent stage in the nuclear fuel cycle. Some separation techniques used have an environmental impact, making these elements available in the environment. In this sense, for this work, simulations were carried out using the PHREEQC program, based on thermodynamic variables and equilibrium constants. The experimental input data were obtained by extracting water in contact with soil from a region of a deactivated uranium mine, followed by analysis by Icp-Ms. The simulations considered different acidity conditions and the presence or absence of organic matter in groundwater. It was possible to distinguish conditions in which the chemical availability of uranium and molybdenum differ, enabling their selective extraction. The simulation showed that the best condition for selective extraction of molybdenum from uranium mine is at acidic ph, since molybdenum forms molybdate (MoO₄^-2) while uranium forms cationic complexes. Under neutral or basic conditions they form similar complexes, confirming the chemical similarity of the elements. (author)