Enriched Uranium Research Articles

The Cell Polarity Protein MPP5/PALS1 Controls the Subcellular Localization of the Oncogenes YAP and TAZ in Liver Cancer

The oncogenes yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are potent liver oncogenes. Because gene mutations cannot fully explain their nuclear enrichment, we aim to understand which mechanisms cause YAP/TAZ activation in liver cancer cells. The combination of proteomics and functional screening identified numerous apical cell polarity complex proteins interacting with YAP and TAZ. Co-immunoprecipitation (Co-IP) experiments confirmed that membrane protein palmitoylated 5 (MPP5; synonym: PALS1) physically interacts with YAP and TAZ. After removing different MPP5 protein domains, Co-IP analyses revealed that the PDZ domain plays a crucial role in YAP binding. The interaction between YAP and MPP5 in the cytoplasm of cancer cells was demonstrated by proximity ligation assays (PLAs). In human hepatocellular carcinoma (HCC) tissues, a reduction in apical MPP5 expression was observed, correlating with the nuclear accumulation of YAP and TAZ. Expression data analysis illustrated that MPP5 is inversely associated with YAP/TAZ target gene signatures in human HCCs. Low MPP5 levels define an HCC patient group with a poor clinical outcome. In summary, MPP5 facilitates the nuclear exclusion of YAP and TAZ in liver cancer. This qualifies MPP5 as a potential tumor-suppressor gene and explains how changes in cell polarity can foster tumorigenesis.

Increased 238Pu Production in Proliferation-Resistant U-10Zr Fuel Produced from Reprocessed Uranium Containing Unseparated 237Np

The sodium-cooled fast reactor (SFR) is a potential candidate for the future production of clean sustainable energy. Some SFR designs planned for construction will use high-assay low-enriched uranium (HALEU) metal fuel enriched up to around 19.75%. However, fast reactor technology faces several criticisms, such as its ability to produce weapons-grade plutonium, the possibility of facility diversion from peaceful use to the production of nuclear weapons–usable materials, and the risk of incentivizing the construction of domestic fuel enrichment programs. To compete with traditional light water reactors (LWRs), SFR technology utilizing HALEU fuel should be developed to be proliferation-resistant and sustainable. In this study, the Serpent 2 Monte Carlo reactor physics code was used to simulate and compare alternative HALEU fuel options that could be implemented to reduce proliferation risk. As part of the comparison, nonpeaceful plutonium diversion pathways were considered. By evaluating its attractiveness for diversion from peaceful use to the production of nuclear weapons–usable material, it was shown that the proliferation resistance of SFR technology utilizing HALEU fuel can be improved. The operation of a once-through fuel cycle SFR utilizing HALEU fuel was simulated, and the performance and material attractiveness of various U-10Zr fuel options were compared. Currently, hundreds of thousands of tons of spent fuel from the operation of LWRs are stored across the world. Most of the heavy metal in this spent nuclear fuel is comprised of reusable uranium and plutonium. Re-enrichment of reprocessed uranium (RepU), with or without the presence of unseparated 237Np, for the production of SFR fuel is one way to simultaneously improve uranium resource utilization and enhance proliferation resistance due to the co-enrichment of 236U and 237Np. The presence of these isotopes in fresh HALEU fuel can increase 238Pu production even at low reactor burnup. Due to its high decay heat and spontaneous neutron emission, 238Pu decreases material attractiveness for nuclear weapons construction. Directly doping fresh fuel with preseparated 237Np requires the separate storage of neptunium, introducing its own nuclear security requirements and proliferation risks. Additionally, due to uncertainty in the separation factor between RepU and neptunium, some neptunium impurities will inevitably remain in RepU following separation. Therefore, this study examined the impact of unseparated 237Np on the production and depletion of U-10Zr fuel. A parametric study comparing fuel options of varying 237Np weight fractions was conducted, and proliferation scenarios considering both clandestine and overt diversion of discharged fuel were considered.

Multiphysics Simulation of an Electrorefiner with Continuous Circulation of Molten Salt for Separation of Uranium and Neptunium

A 3-D continuous electrorefiner is designed and investigated using multiphysics simulation for the separation of uranium and neptunium from spent nuclear fuel in molten salt. The concentration distribution field, the electric field, the ionic flux density field, and the flow field are evaluated under galvanostatic and pulse electrorefining by numerical integration of the governing equations using finite element method. During the electrorefining without molten salt recirculation, the transport of the electroactive cations is controlled by diffusion and electromigration and high concentration gradient is built near electrodes. In a galvanostatic electrorefining with a current density of 50 A·m–2, the concentration of U3+ decreases to 26.7 mol·m–3 near cathode and increases to 62.5 mol·m–3 near anode within 40 s, and no co-deposition of uranium and neptunium occurs. In a galvanostatic electrorefining with a current density of 200 A·m–2, the concentration of U3+ decreases to 1.3 mol·m–3 near cathode and increases to 62.6 mol·m–3 near anode within 6.7 s, and the co-deposition of uranium and neptunium occurs after 0.28 mg of pure uranium is collected. With moderate molten salt recirculation, the transport of the electroactive cations is controlled by convection. The local concentrations of uranium ions approach steady near the electrodes within 32 s in a galvanostatic electrorefining of 50 A·m–2, and no co-deposition of uranium and neptunium occurs. Though the concentration of U3+ decreases to 21.1 mol·m–3 near cathode and increases to 62.6 mol·m–3 near anode within 6.7 s with a current density of 200 A·m–2, there is no co-deposition of uranium and neptunium occurred. In addition, it is proved that the pulse electrorefining does not improve the recovery of uranium compared with galvanostatic electrorefining with a corresponding average current.

Minor actinides transmutation in pressurized water reactors. 2. Using uranium and thorium fuel to burn minor actinides in a system with several VVER reactors

There is currently a consensus among the scientific and engineering community regarding the solution to the problem of minor actinides (MAs) formed in the process of nuclear power operation: MAs need to be converted to fission products during burnup in power reactors. Fast neutron reactors (BN, BREST) and molten salt reactors (MSR) are considered largely to this end. Despite the advantages of using fast reactors, there are no currently power unit designs with BN or BREST reactors available for commercial operation. The possibility of using VVER reactors for this purpose is rarely covered in scientific literature, despite the fact that the technology of light water reactors has long been mastered, and preparing a VVER-based MA burner reactor is technically simpler than on the basis of a pilot commercial BN technology or BREST or MSR reactors at different R&D stages. In the previously published first part of the study by Kazansky and Karpovich 2022, the fuel cycle for VVER reactors was investigated: minor actinides obtained during reactor operation were extracted from spent nuclear fuel and added to fresh fuel for the same reactor. It has been found that implementing this cycle and bringing the concentration of MAs up to 4 wt. % makes it possible to reduce the amount of minor actinides produced in the VVER reactor by a factor of 8, and without a loss in the NPP unit power generation. This paper investigates, based on an idea of closing the fuel cycle in terms of minor actinides, the relationship between the MA burnup depth in a VVER-1200 reactor and the enrichment of fresh fuel, the dynamics of unloaded heavy nuclei, and the amount of MAs in additionally loaded fuel. Under investigation are two types of additionally loaded fuel with oxides of minor actinides added to it: based on enriched uranium dioxide or a mixture of (1 – x) 232ThO2+x (96% UO2) (Kazansky et al. 2023). At the same time, the number of heavy nuclei in fuel does not change when there is a change in the number of loaded MA nuclei, which is measured in the number of the VVER-1200 reactors “served” (the mass of accumulated MA nuclei is about 1% and is removed annually from spent fuel). The number of minor actinides entering fuel is kept at a level that allows having a reactivity margin for the reactor operation at a power of over 2% before the annual refueling. Calculations were undertaken using a fuel assembly model with fuel elements broken down into a number of groups with different fuel burnup depths to simulate the actual loading of the reactor core. This model makes it possible to avoid the power peaking effects and give an answer about the neutronic characteristics of the fuel cycle involving MAs. The calculations made it possible to make a number of important conclusions: more refueling cycles lead to a dynamic equilibrium taking place between the minor actinide amounts loaded and burnt; the number of the reactors served is directly proportional to the enrichment of the make-up fuel and a 20% UO2 enrichment makes it possible to serve up to 23 VVER-1200 reactors, while using 80% 232ThO2 + 20% (96% UO2) fuel allows 17 VVER-1200 reactors to be served; using MAs extracted from SNF with a burnup of 20 to 50 MW*day/kg leads to the MA composition effect on the reactivity balance being within 4 to 5 βeff.

Mitigation of depleted uranium-induced mitochondrial damage by ethylmalonic encephalopathy 1 protein via modulation of hydrogen sulfide and glutathione pathways.

Depleted uranium (DU) is a byproduct of uranium enrichment, which can cause heavy-metal toxicity and radiation toxicity as well as serious damage to the kidneys. However, the mechanism of renal injury induced by DU is still unclear. This study aimed to explore the role of ethylmalonic encephalopathy 1 (ETHE1) in DU-induced mitochondrial dysfunction and elucidate the underlying mechanisms. Using ETHE1 gene knockout C57BL/6 mice (10mg/kg DU) and renal cell models (500µM DU) exposed to DU, we observed significantly reduced levels of hydrogen sulfide (H2S) and glutathione (GSH), alongside decreased adenosine triphosphate (ATP) content and increased oxidative stress. Our results demonstrated that knocking out or silencing ETHE1 led to a significant reduction in H2S and GSH levels, whereas the opposite occurred when was ETHE1 overexpressed. When the H2S donor sodium hydrosulfide and GSH precursor N-acetylcysteine were used to treat animals or cells, cellular ATP levels were increased, oxidative stress markers were reduced, and kidney damage was mitigated. In addition, H2S and GSH interacted with each other after DU poisoning. These findings suggest that the ETHE1/H2S/GSH pathway plays a critical role in mediating DU-induced mitochondrial dysfunction in renal cells, highlighting potential therapeutic targets for mitigating the harmful effects of DU. Thus, this study expands our understanding of DU-induced renal damage pathways, providing avenues for further research and intervention strategies.

Fuel Behavior Implications of Reactor Design Choices in Pressurized Water SMRs

Small pressurized water reactors can feature boron-free operation, natural circulation mode, reduced-height assemblies, and/or long refueling cycles. This paper attempts to explore core design optimization for each of these design evolutions. In consequence, five core design layouts are developed incorporating boron-free operation with continuous control rod insertion, natural circulation with low burnup/low power density design, natural circulation with high burnup/low power density design, forced circulation with standard core power density design, and forced circulation with high power density design. These cores’ performance is compared to a standard four-loop pressurized water reactor. The design process aims to improve the fuel cycle cost under safety constraints through core design optimization using the CASMO4E/SIMULATE3 reactor physics codes and the FRAPCON4.1 fuel performance assessment tool. Core modeling assumes standard 17×17 PWR fuel assemblies loaded with low enriched uranium up to 5 wt% or low enriched uranium plus (i.e. below 10 wt% enrichment) pellets with gadolinium oxide as the burnable poison. Satisfactory core and fuel performances are obtained for all the designed cores under steady state and considered overpower transients. For low power density operation, long cycle lengths are achieved reaching 2.5-year and 5-year cycles, and peak rod-average burnup is pushed to 83 MWd/kgU. Other cycle lengths are maintained at 18 months. Boron-free operation exhibits the ability to achieve longer cycle lengths at the cost of higher peaking factors leading to high local power and fuel temperatures, which prevents sizable power uprates and is deemed uneconomical. Fuel assembly height reduction allows coolant velocity retrofit, which enables higher core power density without violating the structural integrity of the fuel assembly. As a result, a core power density of 123 kW/L is reached where total cladding hoop strain becomes the limiting parameter.

Strategically Designed Ternary Nanohybrids of Titanate Nanosheet and Polydopamine-Coated Carbon Nanotubes for Highly Efficient Enrichment of Uranium(VI).

A strategically designed ternary nanohybrid (TNS-PDA/CNT), consisting of titanate nanosheet (TNS) and polydopamine-modified multiwalled carbon nanotube (PDA/CNT composite), was synthesized by the facile hydrothermal method and wet impregnation method for removal of U(VI) from aqueous solution and were characterized by transmission electron microscopy (TEM), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), Raman spectroscopy, Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS). TNSs were introduced into the PDA/CNT composite, which effectively averted the agglomeration of the CNT and further exposed more adsorption sites. PDA thin layer exposing more active sites was conducive to enhance adsorption capacity and kinetic. The adsorption process was largely influenced by pH values and weakly affected by ionic strength, indicating that the adsorption process was controlled by inner-sphere surface complexes because of TNS-PDA/CNT with multiple functional groups, including imine, catechol, amine, and hydroxyl groups. The isotherm data could be well described by the Langmuir model, and the monolayer maximum adsorption was determined to be 309.60 mg/g at pH = 5.0 and temperature = 45 °C. Thermodynamic parameters (ΔG° < 0, ΔS° > 0, and ΔH° < 0) showed that the nature of adsorption was endothermic and spontaneous. By XRD, FT-IR, and XPS analyses, the adsorption mechanism mainly involved surface complexation and ion exchange. In summary, the TNS-PDA/CNT materials are fully qualified as a satisfactory adsorbent for the purification and recovery of U(VI) from wastewater.

Reconfiguration of the U.S. and Canadian Nuclear Industries

Nuclear energy industry is currently undergoing a renaissance due to its competitiveness in the global energy market and its indispensability in the context of the energy transition and the "climate" agenda of global elites. The USA and Canada are among the leading players in the global nuclear technologies market. They possess uranium reserves and technologies for uranium extraction, conversion, enrichment, nuclear fuel production, and nuclear power plants construction. They also rely on their own well-developed nuclear power sectors, which together account for about a third of the world's nuclear power generation. However, in recent years, the United States and Canada have gradually lost ground in many segments of the global nuclear energy market. A reconfiguration of the North American nuclear industry is currently underway. To a large extent, the new institutional structure of the American-Canadian alliance in the global nuclear technology market has already crystallized around Cameco – Westinghouse Electric consortium, formed under the auspices of the investment group Brookfield, and the CANDU ecosystem. For the United States, the main priority in the field of nuclear energy today is increasing uranium enrichment capacity and overcoming dependence on Russia in this area. In addition, Washington and Ottawa aim to strengthen their positions abroad, both in the construction of new reactors and in the supply of nuclear fuel and uranium mining. They are also working on expanding their own nuclear generation capacities and developing small modular reactors. On the international stage, the institutionalization of the American-Canadian alliance in the field of nuclear energy makes it inevitable that the United States and Canada will attempt to regain market share in atomic energy technologies, nuclear fuel, and uranium raw materials. They will also work to undermine the Russian Federation’s position in these markets, reduce its export revenues, and slow down the development of its nuclear energy industry.

Fission Surface Power—A Conceptual 350-kW(thermal) Microreactor Designed for Lunar Power Around SpaceX Falcon Heavy Mass Constraints

A fast spectrum surface fission power microreactor for lunar deployment is conceptualized and modeled utilizing the primary design drivers of the SpaceX Falcon Heavy mass constraints, a 10-year operation lifetime, high-assay low-enrichment uranium fuel enrichment, a 100-kW(electric) system power rating, and a Stirling conversion cycle. The reactor is demonstrated to remain subcritical during launch accidents resulting in oceanic submersion and throughout control system failures in the highest reactivity positions. Neutron shielding requirements for the high-leakage core were satisfied with 40 cm of natural enrichment LiH at 100% solid density, while photon shielding for the reactor at full power exceeded the in the National Aeronautics and Space Administration scope of work design requirement 18960 DR-3 of 5 rem·y−1 at rates of 30 rem·y−1 for a 1-km standoff. A conversion cycle was approximated using an experimental carbon-carbon thermal radiator coupled with published analytical and experimental results for free-piston Stirling systems.

Verification of uranium composite materials using active interrogation techniques for safeguards purposes

Abstract The uranium isotope characterization for nuclear safeguards and security purposes was conducted using both passive and active non-destructive techniques. The interrogated samples were natural uranium (NU), low-enriched uranium (LEU), and depleted uranium (DU) all in the form of uranium dioxide. The obtained spectra using both techniques were accumulated using a high-efficiency HPGe detector. Improving detector efficiency was developed using the neural network (NN) method based on the obtained intrinsic calibration data. The obtained enrichment results of passive measurements showed good agreement with certified samples to within 1.12% in the case of LEU, 1.03% in the case of NU, and 1.04% in the case of DU.&amp;#xD;Active interrogation of the samples was done using the neutron spectrum of a 5 Ci 241Am-Be neutron source. Seven short-lived fission products (FPs) (101Tc, 97Nb, 105Ru, 92Y, 91Sr, 92Sr, and 88Kr) were chosen as indicators to provide a complete characterization of isotopic mass determination, uranium content, and enrichment. Isotopic masses of the samples were calculated using thermal and fast interrogations. A comparison of the obtained results of 238U mass was found to agree within 0.2% with certified value based on fast interrogation, and within 0.3% of 235U mass based on thermal interrogation.&amp;#xD;

Artificial Photosynthetic Assemblies Constructed by NH2-UiO-66 Decorated with Spatially Separated Dual Cocatalysts for Enhanced Photocatalytic Uranium Reduction.

The phenomenon of rapid migration of photogenerated charges in natural photosynthetic systems has motivated the design of efficient photocatalysts capable of fast charge separation and efficient reaction kinetics for photocatalytically assisted enrichment and separation of uranium U(VI) in uranium wastewater. In this study, we developed a biomimetic photocatalytic system MnOx/NH2-UiO-66-rGO (M/UiO-rGO) with spatially separated dual cocatalysts. Among them, rGO functions to capture electrons and participates in reduction reactions, while MnOx captures holes and participates in oxidation reactions. The M/UiO-rGO catalyst exhibits excellent performance in photocatalytic reduction of uranium (reaching 91.8% in 1 h), and even under natural light conditions, it exhibits excellent uranium removal ability (80.4%). Using multispectral coupling technology, we further confirmed that enriched uranium undergoes a continuous and complex reaction process of "capture-reduction-free radical oxidation-nucleation-crystallization". This work presents a viable strategy for designing biomimetic photocatalysts with efficient charge separation and rapid reaction kinetics for environmental purification purposes.

New Formats of U.S. Nuclear Alliances and Their Impact on the Treaty on the Non-Proliferation of Nuclear Weapons

This article examines the impact of new formats of nuclear cooperation launched by the United States with its allies on the international nonproliferation regime established by the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). The two examples of such cooperation outlined in this article are the AUKUS partnership between Australia, United Kingdom and Untitled States that involves transfer to Canberra of a large amount of highly-enriched uranium for use in nuclear-powered submarines, as well as the extended deterrence between the United States and the Republic of Korea. This material presents the analysis of how (if at all) these initiatives are compatible with the NPT and what the most problematic elements are in each case in relation to the Treaty and its regime. It derives from the research that has been conducted that the new formats of United States’ nuclear cooperation are undermining the NPT regime and its international standing. As a result of such cooperation the NPT loses its unique international legal core that for more than half a century has allowed to stop proliferation of nuclear weapons. The norms that lied in the basis of the Treaty are also being eroded. Such tendencies create a completely new environment and inevitably affect security calculus of other States Parties to the NPT. Against this backdrop further decrease of the political weight of the Treaty cannot be excluded, together with its role in upholding international peace and stability. Such transformations may require a brand new look at and approach to the international nonproliferation regime in the future.

Performance evaluation of uranium enrichment cascades using fuzzy based harmony search algorithm

The production of energy in nuclear reactors needs enrichment of fuels. There is some interest in taking the fuel enrichment level to 3–5% by cascades. Optimization of the isotopic cascades is essential to make this process economic. This study presents a Fuzzy-based Harmony Search (FHS) algorithm aimed at dynamic parameter adaptation as well as establishing a balance between exploration and exploitation, which significantly increases the convergence speed of the algorithm. Accelerating the convergence of the algorithm is demonstrated in the Sphere, Schwefel, Ackley, and Drop-Waves benchmarks at first. This approach also enhances performance in several test cases of optimum cascade problems, with results validated through comparisons with conventional methods. According to the results, the total number of centrifuges using FHS reached 6306 in test case 1, which was reduced 44 pieces compared to the method used by Palkin, and 55 pieces compared to the real coded genetic algorithm. The total number of centrifuges using FHS reached 2808 in test case 4 with a different type of gas centrifuge, which decreased 27 pieces compared to the direct search method. Similar results were obtained in other test cases, indicating the effectiveness of the FHS algorithm in minimizing the total number of centrifuges and total flow rates.

Combining synergistic interaction and ion imprinting to improve adsorption capacity for selective uranium extraction from seawater

Abstract To ensuring the demand for uranium by utilizing unconventional uranium resources, the development of materials for selective capturing uranyl ions is increasingly important. Hence, the ion-imprinted polymer (IIP) based on specific binding sites was designed and prepared for selective enrichment of uranium from seawater. The existence of specific adsorption sites and the corresponding adsorption mechanism were confirmed by a series of experimental analyses and supported by density functional theory (DFT) calculations. Under the influence of seawater environment, the maximal uranium uptake of IIP reached 58.31 mg g−1. Significantly, the mass ratio of U and V (Sr or Ni) adsorbed by IIP was greater than 15, and the adsorption capacity did not change obviously after five cycles of use. The strategy combining ion imprinting and synergistic interaction is expected to improve uranium extraction performance.

Direct, Acid-Free Uranium Purification from Solid Analytical Waste by Supercritical Carbon Dioxide Extraction with Incinerable N,N-Dialkyl Amide Adducts

Direct, Acid-Free Uranium Purification from Solid Analytical Waste by Supercritical Carbon Dioxide Extraction with Incinerable <i>N</i>,<i>N</i>-Dialkyl Amide Adducts

MHD Mass Transfer Flow in Presence of Chemical Reaction, Thermal Radiation, and Thermal Diffusion Effect

ABSTRACTThe present work is interested in investigating the impacts of chemical reaction, magnetic field, thermal radiation, heat sink, and thermal diffusion on a steady two‐dimensional MHD convection‐free heat and mass transfer flow past a semi‐infinite upright porous plate. The dimensionless domain equations are solved analytically using the perturbation technique for two distinct scenarios: (a) small suction and (b) large suction. The effects of various crucial parameters on velocity, temperature, concentration, as well as on the skin friction, Nusselt number, and Sherwood number are graphically illustrated, and the subsequent discussion is rooted on the derived outcomes. Graphical representations were created utilizing MATLAB software. The results suggest that an increase in the Soret effect elevates both the momentum and concentration boundary layers while reducing the mass transfer rate, regardless of the suction intensity. Our research also identified a captivating result where fluid velocity escalates with higher magnetic values in the scenario of large suction, while it demonstrates contrasting behavior under small suction condition. The present investigation holds significant relevance across various industrial sectors, including uranium enrichment, petrology, petroleum reservoirs, polymer fractionation, among others.

Modeling detector response curves for a high-fidelity uranium measurement for use in simulations

Enrichment measurements using identiFinder2 (‘HM5’) detector are performed on two Material Testing Reactor (MTR) fuel assemblies - one with low-enriched uranium plates (LEU) and another with high-enriched uranium plates (HEU). The effectiveness of International Atomic Energy Agency (IAEA) inspection plans for verifying nuclear material strata, in the form of defect detection probability (DP), is evaluated using statistical models. These models use defect identification probability (IP) curves, which represent the probability that a measured item is identified as a defective item. This paper describes a new modeling procedure that converts the experimental measurements into IP curves and employing such experimentally derived IP curves within DP simulations will better represent the experimental conditions like material type, material distribution, and plate configuration. A comparison of experimental performance curves to a simple statistical model (Gaussian, 15% relative standard deviation RSD) shows that the DP results from the modeled response of HM5 measurements better captures the experimental conditions. This result highlights a need for further research into experimental error variables test model development as use of a simple model does not adequately capture true performance in either the LEU or HEU cases.

Coordination-Induced Magnetism Strategy for Highly Selective and Efficient Uranium Separation.

Highly efficient separation of dispersed uranium is important for the sustainable development of nuclear industry, and adsorption is the most recognized approach. However, there are many coexisting interfering metal ions that compete with uranyl ion for the chelating ligands in the adsorbents and lead to low separation selectivity and efficiency. Herein, a coordination-induced magnetism strategy is presented for the separation of uranium based on the conversion of diamagnetic cyanoferrocene (Fc-CN) nanocrystals to uranium-containing magnetic recoverable ferromagnetic aggregates. Different from previous adsorption strategies, this strategy combines the mechanisms of photocatalytic uranium enrichment and chemical uranium adsorption. Under light irradiation, electron of Fe(II) in Fc-CN is excited and transfers to uranyl ion via the cyano group to form tight coordination bond between N atom in cyano group and uranium. This phenomenon is unique for uranyl ion, and thus, a high uranium removal rate of 97.98% is achieved in simulated nuclear wastewater with the presence of tremendous interfering ions, proving its highly selective and efficient uranium separation performance. The ability to form highly stable magnetic aggregates via photoinduced interaction between Fc-CN and uranium enriches the understanding on the chemical properties of Fc-CN and uranium.

Carboxymethyl cellulose-assisted preparation of magnetic metal–organic framework nanocomposites with antifouling for efficient uranium enrichment

A magnetic metal–organic frameworks nanocomposite (FCMCZA) was prepared by solvothermal and in situ growth method for efficient antifouling and uranium enrichment. A series of characterization tests were carried out by SEM, XRD, XPS, FTIR and N2 adsorption–desorption analyses. The FCMCZA exhibited the distinct core–shell structure with high specific surface areas (793.86 m2/g) and abundant functional groups. The saturated magnetization and algae death rate of FCMCZA reached 33.5 emu/g and 41 %, respectively. The maximum adsorption capacity of FCMCZA was 238.66 mg/g at pH 8.0, calculated from Langmuir model. Importantly, the removal capacity of FCMCZA remained 87.29 mg/g after four cycles. The high removal rate (62.9 %) and uranium uptake (11.7 μg/g) in actual seawater further proved its application potentiality.

The role of hydrothermal alteration in uranium mineralization at the Xiaoshan uranium deposit, South China

Hydrothermal alteration can be utilized to constrain element migrations during mineralization, as it records the effects of fluid-rock interactions. Previous studies have suggested that uranium in deposits primarily originates from uranium-bearing granites; however, limited knowledge exists regarding the leaching mechamisms of this element and rare earth elements (REEs) from these rocks. In recent years, the Xiaoshan Deposit, a newly discovered medium-sized uranium deposit, has been discovered in the central part of the Lujing uranium ore field, South China. In this study, we examine this deposit to investigate hydrothermal alterations and their impact on elemental mass change. The deposit exhibits seven types of alteration including K-feldspar, albite, illite, sericite, muscovite, quartz and chlorite alteration. These alterations follow a certain sequence, starting from chlorite alteration, followed by widespread K-feldspar alteration, then to albite alteration, accompanied by muscovite alteration, and finally illite, sericite and quartz alteration. The main uranium mineralization stage was coeval with the late acid siliceous hydrothermal fluid, illite and sericite alteration. The pre-ore alkaline alteration (K-feldspar alteration) resulted in the leaching and extraction of uranium, leading to the precipitation of a significant amount of apatite in mineral interstices and initial uranium enrichment (ΔCi (U) = 16.52 ppm). This process facilitated material preparation for subsequent acidic alterations and localized ore enrichment. The original dense rock structure was disrupted, creating fractures/cavities that served as conduits for uranium mineralization. Moreover, under alkaline metasomatism, uranium and REEs was extensively leached out of uranium-bearing accessory minerals such as the apatite. According to apatite compositional variations and alteration geochemistry, these variations reveal the process of uranium dissolution, migration, and precipitation enrichment into ore bodies. Uranium was completely released during alkaline metasomatism, causing a sharp decline in U content from 53.1 ppm to 0.96 ppm. The formation of alkaline alteration fluids facilitates the extraction of uranium from the surrounding rocks (the Indosinian granite).