Journal of Radioanalytical and Nuclear Chemistry最新文献

An efficient sodium phosphate-doped silica gel nanocomposites (SG-SDP) material was successfully produced and used to collect uranyl ions from an aqueous solution via batch sorption. The nanocomposite was characterized using ATR-FTIR, SEM, XPS, and XRD techniques, and its thermal stability was determined with TGA. The efficiency of SG-SDP to capture uranyl ions was evaluated using a variety of factors, including temperature (T), pH, contact time (t), and initial concentration (C_i). Under particular conditions (pH = 2, C_i = 1.0 mg L⁻¹, T = 55 °C, 80 rpm, and dosage = 2 g L⁻¹), sorption equilibrium is reached in 40 min, resulting in the greatest elimination percentage of 90%. The binding of U(VI) ions conformed to the Langmuir isotherm model (R² > 0.999), and the interaction followed a pseudo-second-order kinetic model (R² > 0.999). These positive results indicate that the SG-SDP nanocomposite material can be used effectively to remove diluted uranium (VI) ions from water.

Radon (²²²Rn), among all natural radiation sources, is considered the most hazardous to human health. This study evaluated the ²²²Rn concentration and radiological risk in the surface water and groundwater in Dareta Village. The water samples were randomly collected, and ²²²Rn was measured using a DURRIDGE-RAD7 analyzer. The mean ²²²Rn concentration was in the range of 2.64 ± 0.10–12.30 ± 3.20 Bq/l, and the mean of the total annual effective dose was 12.54–82.02 µSv/y. Based on these findings, it can be concluded that the ²²²Rn concentrations were safe, except for ZGW-01 and ZGW-02. However, it is recommended that water samples be treated before consumption.

The safe disposal of radioactive sludge generated from the use of nuclear energy is crucial. In this study, the simulated radioactive sludge was successfully vitrified via microwave sintering with the addition of NH₄H₂PO₄, forming Na₂O-Al₂O₃-Fe₂O₃-P₂O₅ (SAIP) system glass, and monazite glass–ceramic was simultaneously produced. The phase evolution, microstructure, density, and chemical stability of the sintered samples were systematically researched. The results indicated that vitrification of the sintered samples can be achieved when the NH₄H₂PO₄ content in the radioactive sludge reaches 65 wt.% at temperatures of 1200 °C and 1300 °C. The maximum solid solubility level of Nd in the glass structure was 45 wt.% at 1200 °C and 46 wt.% at 1300 °C. Moreover, the density of the sintered samples ranged from 2.62 to 3.12 g/cm³, and they exhibited excellent leaching resistance. The results of this study provide a new perspective for the safe disposal of radioactive sludge.

This study has checked ²²²Rn concentrations in groundwater from 27 sites of Haridwar and Dehradun, Uttarakhand, using the Durridge RAD-7. Seasonal variability reveals that the activity of radon is at its peak during the monsoon. Among the samples, 96.29% exceeded the United States Environmental Protection Agency’s Maximum Contaminant Level for radon during monsoon. The results indicated significant correlations between the concentration of radon and some factors like electrical conductivity and pH. The objective is to compare seasonal radon levels in groundwater, identify significant variations, and assess potential health risks by evaluating them against established safety guidelines.

A method for depositing actinides directly onto a 4H-SiC Schottky barrier diode (SBD) detector as a field deployable actinides sensor was developed to enable off-site analysis, shortening the time to obtain critical information such as elements, concentration, and/or isotopic ratio related to the radiological situation. A thin film of Hg was first electrodeposited onto the Pt contact of the SiC diode, followed by chronoamperometric deposition of microgram levels of actinides under conventional control conditions. The 4H-SiC diode maintained consistent functionality through the electrodeposition process and showed resolved alpha-energy spectra that contained accurate isotopic information demonstrating the feasibility of a combined chemical and radiological sensor for field actinide detection and quantification.

Ionic liquids, known as “green solvents”, have a wide electrochemical window and radiation stability, making them valuable in spent fuel reprocessing. This paper traces the development of ionic liquids, reviews the advances in research on the dissolution and electrochemical behavior of uranium in these solvents, and analyses the factors contributing to their distinct electrochemical behavior. For plutonium, research on its electrodeposition is scarce; however, it has been discovered that it can be electrodeposited in ionic liquids with bis(trifluoromethylsulfonyl)imide (NTf₂⁻) as the anion. Finally, the key research directions in this field are prospected.

In this study, activity of ²³⁸U,²³²Th, and ⁴⁰K was determined in coal, bottom, and fly ash samples collected from in and around the thermal power plant area of Cuddalore district, Tamil Nadu. The mean activity concentration for ²³⁸U, ²³²Th, and ⁴⁰K in coal were (45 ± 0.4, 28 ± 0.2, and 145 ± 0.5 Bq kg⁻¹) and ash samples were (103 ± 0.5, 31 ± 0.5, and 334 ± 0.6 Bq kg⁻¹), respectively. To assess the radiation hazards, calculated radiological parameters are compared with permissible limits. This result indicates that the indoor (1.15 × 10^–3 mSv y⁻¹) and outdoor (0.56 × 10^–3 mSv y⁻¹) excess lifetime cancer risk is slightly greater than the permissible limit and cluster analysis was performed to understand the relation between the variables.

In deep geological repositories for high-level radioactive waste, the bentonite buffer undergoes thermal, hydrological, mechanical, and chemical (THMC) processes. This study aims to clarify the significance of the mechanical process in the THC evolution of bentonite by comparing a THC model with a coupled THMC model for a generic repository. The comparison shows that the impact of the mechanical process on hydrological and geochemical changes is significant during the early unsaturated stage but diminishes in the later stages once the bentonite is fully saturated. This suggests that considering mechanical processes may not be essential for long-term radionuclide migration models.

Uranium and plutonium isotopes were determined in bivalve mollusks from several coastal areas of Mexico. Four specimens of clam (Gallo, Chocolata, Chirla and Pata de Mula) and one of oyster (American) were acquired at a local distribution center. The radionuclides were extracted and purified using radiochemical procedures and measured by alpha spectrometry. In most cases, the activity concentration values of uranium and plutonium ​​were greater in the shell than in the soft body of bivalves. The activity concentrations of ²³⁸U and ^239+240Pu in the bivalve shell were between 0.21 and 1.29 Bq/kg, and 0.02 and 0.21 Bq/kg, respectively. The values ​​for ²³⁸U and ^239+240Pu in the soft body of bivalves were between 0.06 and 1.14 Bq/kg, and 0.004 and 0.09 Bq/kg, respectively. Hierarchical cluster analyses applied to data analysis revealed that the majority of samples were grouped into two clusters identified as Gulf of Mexico and Mexican Pacific due to their origin. Hence, the differences in activity concentrations may be associated with the content of the radionuclides in the medium where the specimen was developed. The accumulation of actinide elements in bivalve mollusks may be useful to evaluate the level of contamination due to heavy metals in the Mexican marine environment.

The sorption and precipitation of Ra and Ba on crystalline rock was studied with batch sorption and precipitation experiments, and geochemical modeling. Following the precipitation experiments, (Ba,Ra)SO₄ experimental partition coefficient (λ) and RaSO₄(s) solubility constant values were obtained. It was observed that especially in groundwaters of low overall salinity, and/or of high SO₄ and Ba content, Ra is strongly removed from the solution to both coprecipitation and sorption. A new geochemical model was developed which successfully interprets the experimental results. The precipitates of BaSO₄(s) were directly observed with the rock minerals with a SEM/EDX analysis.