Radiochemistry最新文献

139 crystallographically nonequivalent adipate ions exhibit eight topologically different types of coordination to f-metal atoms in the crystal structures. Unlike other aliphatic dicarboxylate ions, all types of coordination of adipate ions lead to the formation of only four-membered chelate rings. A new method for quantitatively assessing the conformation of chains containing six carbon atoms linked by single C–C bonds was tested using adipate ions as an example. In known structures, adipate ions realize six different conformations, each of which corresponds to a certain “double” symbol: φ³/φ³, φ¹/φ³, φ¹/φ¹, φ²/φ³, φ¹/φ², or φ²/φ². Most often (≈97% of cases), energetically more favorable combinations of odd transoid φ³ and/or skewed φ¹ conformations are realized.

The paper presents the annual variability of ²²⁶Ra and ²²⁸Ra isotope concentrations, nutrients content, and hydrological parameters in coastal waters of the karsted area near Cape Aya in the period from 2019 to 2025. The minimum radionuclide concentrations correspond to dry periods (2021, 2023–2025). The ²²⁸Ra/²²⁶Ra isotope activity ratio was shown to be an indicator of freshwater influence even without significant salinity decline. The extent of the freshwater plume originating from the karst cavity was determined. Seasonal fluctuations in temperature, salinity, and biogenic elements were governed by meteorological conditions and the intensity of biogeochemical processes. The estimated submarine groundwater discharge (SGD) rate during the period from 2019 to 2025 ranged from 5.47 to 13.5 thousand m³/day, correlating with precipitation inputs and the duration of dry periods preceding sampling.

Radioactive specimens of borosilicate glasses containing HLW short-lived fraction from the raffinate of the first extraction cycle of SNF reprocessing were fabricated at the hot cell vitrification unit of the radiochemical plant. The glasses were identical in their chemical composition but differed in the content of the cesium–strontium fraction. The proportion of radioactive isotopes in the specimens of each glass composition corresponded to the specified heat generation rates of 1, 15, 25, and 35 kW/m³, while the waste form specific activity ranged from 150 to 4600 Ci/kg. Chemical durability of the radioactive glass specimens was tested. The cesium and strontium leaching rates did not exceed 1 × 10^–4 g/(cm² day) at any point of the run.

The solubility of radium, barium, and lead nitrates in aqueous solutions of acetic acid and its mixtures with 0.5 to 16 M nitric acid was determined. For aqueous solutions of acetic acid, the solubilities of radium, barium, and lead nitrates decrease monotonically with increasing mass fraction of CH₃COOH, and for glacial acetic acid they are 0.0027, 0.010, and 0.069 g/kg solvent, respectively. For mixtures of acetic and nitric acids, the solubilities pass through a minimum corresponding to 96–99 wt % CH₃COOH.

Argentina currently operates three nuclear power plants (NPPs) and hosts five research reactors, with a sixth one under construction, along with several nuclear facilities. The estimated decommissioning dates for the first NPPs are projected around 2046. The National Atomic Energy Commission (CNEA) is mandated to determine the decommissioning procedures for nuclear facilities in Argentina and has the responsibility of dismantling and decommissioning Argentine NPPs. Unfortunately, despite a prior Nuclear Facilities Decommissioning Sub-Program, this initiative was discontinued, leading to retirement or reassignment of many involved personnel. Now, the National Radioactive Waste Management Program (PNGRR) within CNEA is developing a Comprehensive Decommissioning Plan for Argentina’s nuclear facilities. This plan is crucial to address current and future generations’ interests and legal responsibilities of CNEA. The plan starts with decontamination and dismantling tasks for selected nuclear facilities as case studies. The Comprehensive Decommissioning Plan progresses through three stages with incremental goals: surveying the current situation, defining strategies, and implementing them. Each phase involves coordinating research and development efforts, planning strategies based on knowledge management, and transferring information between past and present professional and technical personnel. Additionally, specific techniques and technologies will be applied in precise case studies, competencies will be mapped to design tailored training and human resources development programs, and international cooperation agreements will be fostered to exchange knowledge on the subject.

The correlation between the natural radioactivity, pH, and microbial load in rock samples collected in Perumbakkam, a suburb of Chennai, Tamil Nadu, India, was studied. Gamma spectrometry was employed to quantify the concentrations of radionuclides (²³⁸U, ²³²Th, and ⁴⁰K), and associated radiological risk was appraised through indices such as Ra_eq, AEDE, and hazard indices. The concentration of microbes was evaluated by means of the pour plate technique, and pH of an aqueous suspension was determined. Pearson correlation coefficients and Thompson-style plots were then used to explain the relationships between the radiological, chemical, and biological parameters. The results show a strong association of the radiological variables and distributed, locally specific impact with the pH and microbial activity. Site W3 had highly increased radiology levels, showing possible environmental and farming issues. The paper highlights the need for an evaluative combination of sustainable land use and radiology safety.

This review summarizes data from experimental, mechanistic, and translational literature on the radiosensitizing effects of engineered nanoparticles (NPs)—principally gold (AuNPs), silver (AgNPs) and magnetic core–shell hybrid Fe₃O₄@Au constructs—in in vitro cancer models. We summarize common nanoparticle physicochemical characterizations, typical in vitro protocols (cell lines, dosimetry, and endpoints), and major biological readouts (viability, clonogenic survival, γH2AX foci, ROS). Across studies, highZ NPs (Au, Ag) and hybrid formulations frequently increase radiationinduced DNA damage and oxidative stress and reduce clonogenic survival, although the efficacy varies with the particle size, surface chemistry, concentration, cellular uptake, beam energy, and cell type. We synthesize mechanistic evidence supporting three principal mechanisms of nanoparticle radiosensitization—physical dose amplification, chemical ROS amplification, and biological modulation of DNA repair and cell death pathways—and discuss limitations that have delayed clinical translation (toxicity, dosimetry, biodistribution, reproducibility). Finally, we provide a prioritized set of recommendations to accelerate translation to in vivo validation and clinical testing.

Methods of physicochemical analysis, thermodynamics, and kinetics were used to interpret the sorption interaction of the new graphene oxide composite TiO₂||C and of TiO₂ derived from it with La(III) and Ce(III) ions in the Henry region. The variance analysis of experimental sorption isotherms showed the identity of the sorption characteristics of TiO₂||C and TiO₂ in the framework of the Langmuir model. The sorption equilibrium in the systems under consideration was proved by the coincidence of the experimental and literature values of the La(III) and Ce(III) ion hydrolysis constants and the data of sorption kinetics. The presence of surface terminal and bridging OH groups in TiO₂, according to ¹H NMR data, allowed using a model of surface complexation with the participation of functional groups {≡TiOH⁰} and {≡TiO^–} to describe the sorption. Varietal Henry’s constants of sorption of hydroxy and carbonate complexes of La(III) and Ce(III) within the framework of the two-K_a model were found. The pH region of extremely high values of logK_d [mL/g] = 6 in the region of predominance of hydroxo and carbonate complexes was experimentally established.

The presence of colloids in groundwater can significantly complicate the behavior of radionuclides under the conditions of deep geological repository (DGR) of radioactive waste. To ensure the safety of radioactive waste disposal in the host rock environment, it is necessary to thoroughly study the properties of the colloids formed and determine their influence on the retention of radionuclides by crystalline rocks. This work investigates the influence of colloidal particles of bentonite from the Tagansky deposit on the sorption of ¹³⁷Cs, ⁹⁰Sr, ²⁴¹Am, ²³⁹Pu, and ²³⁷Np on samples of the host rock from the Yeniseisky site. Kinetic dependences were obtained, and the quantitative parameters of sorption of the above-listed radionuclides in a model groundwater solution on the colloidal fraction of bentonite from the Tagansky deposit and on intact rock samples were determined. A comparison of the sorption capacity of clay colloids and host rocks showed that the host rock makes a major contribution to the sorption of cesium and strontium, whereas plutonium and neptunium are predominantly retained by the colloidal fraction. The formation of even a small amount of colloidal material from engineered safety barrier materials influences the behavior of radionuclides under DGR conditions.

The extraction of rare earth elements and americium from nitric acid media with solutions of 2-ethylhexyl hydrogen 2-ethylhexylphosphonate (P507 or PC-88A) in Isopar M diluent was studied. A set of chemical extraction reactions was proposed for describing the dependence of the rare earth element (REE) distribution ratios on the nitric acid concentration with an error of less than 10%. The degree of zirconium extraction from nitric acid solutions into 30% P507 exceeds 99.5%. In the process, the zirconium salt of P507 (ZS P507) is formed in the solvent phase; it exhibits secondary extraction properties with respect to REEs. The dependences of the REE distribution ratios in the ZS P507 solution on the nitric acid concentration can be described using the extraction reactions similar to the equations for REE extraction with P507 solutions.