Journal of Radioanalytical and Nuclear Chemistry最新文献

In this study, the long-term variation in ¹³⁷Cs in surface water of the southern Philippine Sea (SPS) was reconstructed. Owing to the influence of local fallout, significantly high levels of ¹³⁷Cs emerged during the late 1950s. Afterward, ¹³⁷Cs in SPS surface water decreased exponentially from 1965 to 2010, with an effective half-life of 14.0 ± 0.7 years. Since 2011, the ¹³⁷Cs activity concentration in SPS surface water has increased slightly, which could be a consequence of the arrival of Fukushima-derived ¹³⁷Cs into the SPS entrained by the ocean current in the subtropical gyre. However, more observational data are needed in this regard.

Thirty-six sand samples collected along the northeast coastal strip in Sri Lanka were analyzed using gamma-ray spectrometry. ²³²Th, ²²⁶Ra, and ⁴⁰K specific activities ranged from < MDL (Minimum Detection Limit) of each radionuclide to 2106 ± 47 Bq kg^− 1 (average 470 ± 3 Bq kg^− 1), 937 ± 20 Bq kg^− 1 (average 230 ± 2 Bq kg^− 1), and 345 ± 157 Bq kg^− 1 (average 152 ± 6 Bq kg^− 1), respectively. Annual effective dose rate (AEDR) ranged from 0.0079 ± 0.0008 mSv y^− 1 to 2.1 ± 0.04 mSv y^− 1. 10 locations in Pulmoddai, Kuchchaveli, and Arisimale regions exceeded the global AEDR.

The ability of plants to absorb and accumulate nutrients and metals is strongly influenced by environmental factors. This study employed neutron activation analysis to evaluate the transfer of essential and toxic elements from soil to rice stems and grains. Results indicated that concentrations of iron (Fe), cobalt (Co), and zinc (Zn) in Soc Trang soil were markedly higher than in Kien Giang, with Fe and Zn 1.8 and 2.9 times greater, respectively, while organic material (OM) was 3.4 times higher in Kien Giang. Variations in Fe and Zn affected arsenic (As) uptake, whereas OM negatively correlated with potassium (K) and Fe transport into grains, emphasizing the role of soil composition in nutrient absorption.

This study presents a comprehensive investigation into the production of ¹³⁹Pr, encompassing both theoretical and experimental approaches. The theoretical aspect of the research involves an in-depth exploration of various excitation functions for potential reactions leading to the production of ¹³⁹Pr. Using the TALYS-1.9 code, a wide array of reactions involving different targets (Ce, La, Nd, and Pr) and projectiles (protons, deuterons, and alphas) was analyzed. The results from the TALYS code revealed that ¹⁴⁰Ce served as the most promising target. Subsequently, the SRIM code was employed to determine the optimal thickness of the ¹⁴⁰Ce target for the proposed reactions. In the experimental approach, the preparation of the target was done using tablet method, resulting in the creation of four disk-shaped tablets. These tablets were then subjected to irradiation with a proton beam in the energy range of 30 MeV. The outcome of this comprehensive study culminated in a substantial production yield of 34.2 mCi/u.A.h, demonstrating excellent agreement with similar experimental processes conducted by other researchers.

The 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester (HEHEHP) extractant exhibits a strong affinity for uranium (U(VI)) and thorium (Th(IV)), facilitating their extraction but complicating their stripping. After prolonged cycling, the HEHEHP organic phase accumulates significant amounts of U(VI) and Th(IV), which not only degrades the extractant’s recyclability but also poses radiological hazards to the working environment and personnel. This study systematically investigates the stripping process and mechanisms for removing U(VI) and Th(IV) from the HEHEHP organic phase using sodium carbonate (Na₂CO₃) as the stripping agent. Experimental results demonstrate that Na₂CO₃, owing to its high alkalinity and strong CO₃²⁻ dissociation, exhibits excellent U(VI) stripping efficiency. A novel approach combining "complete saponification with sodium hydroxide (NaOH) followed by low-concentration Na₂CO₃ stripping" was proposed, achieving efficient U(VI) stripping and separation. The optimal stripping conditions were determined as follows: a Na₂CO₃ concentration of 0.25 mol/L, an organic-to-aqueous phase ratio of 1:2, and a temperature of 30 °C. Under these conditions, a two-stage cross-flow stripping process achieved a U(VI) stripping efficiency of 99.35%, with a uranium product purity of 83.72%. By analyzing the ionic states of U(VI) and Th(IV) at varying pH levels, the migration and transformation behaviors of these elements in carbonate media were elucidated. At pH > 10, Na₂CO₃ stripping primarily converts U(VI) into Na₄UO₂(CO₃)₃ while Th(IV) precipitates as Th(OH)₄, enabling effective separation of U(VI) and Th(IV). This research provides a theoretical foundation and a practical methodology for removing radioactive elements in rare earth separation processes while enabling the resource recovery of uranium and thorium.

Thorium (Th), a promising nuclear fuel, requires accurate detection for efficient resource utilization. This study employed LIBS combined with PLSR and RF models to quantify Th in complex ores. Training set augmentation significantly improved prediction accuracy, reducing RMSEP to 495.58 ppm (PLSR) and 306.00 ppm (RF). PCA-based dimensionality reduction followed by SVM and RF classification yielded accuracies of 97.92% and 87.5%, respectively. Results highlight the effectiveness of training set optimization and hybrid modeling in enhancing LIBS performance. The proposed approach enables rapid, in situ Th analysis, offering strong support for thorium resource exploration and nuclear energy development.

Uranium garners enough attention, not only as a high priority contaminant but also as the major infrastructure of nuclear energy systems. This review comprehensively discusses uranium(VI) capture by zeolite-based materials. Among various factors, pore size and pH play critical roles. Morphological control, surface modification and composite formation are effective to promote uranium capture. Mesoporous SBA-15 and MCM-41 with surface modification have uranium(VI) adsorption of 804.8 and 807.3 mg/g, and show prospects for uranium extraction from seawater. The updated understanding feeds back design of zeolite-based scavengers, which hopefully resolve the burgeoning energy demand and deteriorating ecological environment towards a sustainable society.

Copper-64(T_1/2 = 12.701 h) is a useful radioisotope for positron emission tomography (PET). This study explores its efficient preparation process through FLUKA simulation calculations combined with the actual production of a 10 MeV low-energy cyclotron. Using ⁶⁴Ni as the electroplating raw material to prepare the target, a 30 μA proton beam currents was used to bombard for 4–12 h, and ⁶⁴Cu was obtained through radiochemical separation with an anion-exchange column. The quality control results show that the production capacity of ⁶⁴Cu is 7.92–34.3 GBq, the radionuclidic purity is > 99.9%, the radiochemical purity is > 99.0%, and the content of metal impurities is all < 0.1 μg/GBq. This preparation process is stable, with controllable quality, reaching the level of large-scale production. It can provide a reference for other medical institutions to prepare new solid-target radionuclides using low-energy medical cyclotron, facilitate the research and development and clinical transformation of ⁶⁴Cu-labeled drugs, and bring benefits to cancer patients.

Graphite surface is modified in the present study using cetyltrimethylammonium bromide and the resultant material, graphite-CTAB is evaluated as an adsorbent for ⁹⁹Mo(VI) anions. The surface modification was confirmed through Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) surface area analysis. The introduction of CTAB onto the graphite surface resulted in the incorporation of positively charged quaternary ammonium groups (–N⁺(CH₃)₃), which significantly enhanced the adsorption capacity by enabling strong interactions with molybdate species. Batch adsorption experiments demonstrated that the optimal conditions for molybdenum adsorption occurred at pH 3. Equilibrium was rapidly attained within one hour, and an adsorbent mass of 0.1 g was found to be optimal. Adsorption efficiency decreased at higher ionic strength of the solution using NaCl. Desorption studies identified Na₂CO₃ as the most effective desorbing agent for recovering molybdenum from graphite-CTAB. Kinetic modeling of the adsorption data best fit the pseudo-second-order model, suggesting chemisorption. Furthermore, equilibrium data were well described by the Langmuir isotherm model, indicating monolayer adsorption on a homogeneous surface, with a maximum adsorption capacity of ⁹⁹Mo(VI) of 18.6 mg/g. Thermodynamic analysis revealed the process to be spontaneous, endothermic, and overall favorability of the adsorption process.

This study evaluates the radiological health risks associated with naturally occurring radionuclides (²²⁶Ra, ²³²Th and ⁴⁰K) in 10 breakfast cereal and 15 biscuit samples commonly consumed in Turkey. Activity concentrations were measured using a NaI(Tl) γ-ray spectrometer and ranged from 8.3 to 18.9, 4.1–16.4 and 49.1–125 Bq kg⁻¹, respectively. Estimated mean annual ingestion doses were 143 µSv y⁻¹ (children) and 130 µSv y⁻¹ (adults) from cereals, and 140 µSv y⁻¹ (children) and 127 µSv y⁻¹ (adults) from biscuits, all below the ICRP 1 mSv y⁻¹ limit. Average ELCR values were 1.8 × 10⁻⁴ (children) and 3.4 × 10⁻⁴ (adults) for cereals, and 1.0 × 10⁻⁴ (children) and 3.3 × 10⁻⁴ (adults) for biscuits, aligning with UNSCEAR estimates. Although risks are low, regular surveillance of food radioactivity remains important.