Journal of Radioanalytical and Nuclear Chemistry最新文献

This study aims to evaluate the effectiveness of GSProcessor, a newly developed software designed to enhance the analysis of scintillation gamma-spectra for environmental radiation monitoring. GSProcessor addresses challenges such as interference and self-absorption by employing a spectrum decomposition technique. Soil samples from various depths were analyzed using NaI(Tl) scintillation detectors, with results validated against those from HPGe detectors. Calibration was conducted using certified point sources, and spectra were processed using GSProcessor, ASW software, and Genie-2000 software. The findings demonstrate a strong agreement in the specific activities of ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs across the three software tools. Notably, GSProcessor successfully determined the activity of the low-intensity cosmogenic radionuclide ⁷Be, highlighting its sensitivity and accuracy. These results suggest that GSProcessor is an effective and cost-efficient tool for gamma spectrometry in environmental radiation monitoring. Future work will involve validating the software with more complex radionuclide compositions to expand its applicability in radioecological studies and nuclear facility assessments.

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.

Sorption of Mo(VI) from aqueous solutions onto nano zirconium hydroxide gels was studied using ⁹⁹Mo radiotracer. The acid–base titration curves showed that the prepared nano Zr(OH)₄ gels, Gel #1 and Gel #2, were amphoteric materials with points of zero charge (PZC’s) at pH 2.8 and 3.3, respectively. The highest distribution coefficients of molybdate(VI)-⁹⁹Mo between both gels (Gel #1 and Gel #2) and Cl⁻ media were achieved at pH 2. The maximum sorption capacities of Gel #1 and Gel #2 were found to be 165.7 ± 7.5 and 195.4 ± 8.1 mg Mo/g, respectively. The prepared ⁹⁹Mo/^99mTc chromatographic column generator based on Gel #2 (achieving the higher Mo capacity) showed a good performance; the ^99mTc elution yield was 82.7 ± 2.0%, pH of the eluate ranged from 5 to 6.8, and ⁹⁹Mo breakthrough in the eluted ^99mTc was 0.005 ± 0.002% with a radiochemical purity of 97.3 ± 0.9% (as ^99mTcO₄⁻).

Electrochemical, kinetic and thermodynamic properties of Ce(III) in LiCl–KCl melts were studied on both Mo and liquid Al electrodes using different electrochemical techniques. The results revealed that the reduction of Ce(III) on the Mo electrode followed a quasi-reversible process consisting of a one-step transfer of three electrons, while an irreversible process was recorded on the liquid Al electrode. Ce was successfully extracted by liquid Al electrode from LiCl–KCl melt by potentiostatic electrolysis. This work might open new avenues for the use of liquid Al electrodes for efficient extraction of lanthanides and actinides from molten salt.

This study delineates the intrinsic composition of naturally occurring radioactive material (NORM) waste and affirms the viability of the carbothermal reduction method for the transformation of Ba(²²⁶Ra)SO₄ into Ba(²²⁶Ra)S. The waste was solubilized using ethylenediaminetetraacetic acid, and its constituents were determined employing X-ray diffraction and inductively coupled plasma-atomic emission spectrometry, identifying barium sulfate (BaSO₄) as the predominant component at a weight percentage of 67.13%. Thermodynamic calculations of the carbothermal reduction process were conducted utilizing the HSC Chemistry software, followed by systematic kinetic validation experiments with BaSO₄ as a proxy for Ba(²²⁶Ra)SO₄. The results demonstrate that carbothermal reduction of BaSO₄ initiates at temperatures surpassing 776 °C. The conversion efficiency of BaSO₄ to BaS is markedly influenced by temperature, with the rate escalating from 47.48% to 89.83% as the temperature is incremented from 850 °C to 950 °C. This method effectively converts the very insoluble NORM waste into readily soluble forms of Ba and Ra.

A rapid radiochemical separation method was developed for the assessment of uranium in urine using indigenously synthesised amidoximated crosslinked polyacrylonitrile (ACPAN) adsorbent. The synthesised adsorbent exhibited a high uranium adsorption capacity for urine samples conditioned at pH 2. The reusability of the ACPAN adsorbent was demonstrated by its stable adsorption capacity for ultra-trace levels of uranium over multiple cycles. The standardized method complied ANSI 13.30 radio bioassay performance criteria, validating the suitability of this novel technique for precise determination of uranium in urine. The method developed is rapid, sensitive, and can be applied for emergency bioassay of uranium in urine.

The effect of conventional factors on the free radon production rate above 0 °C has been widely studied, but rarely explored under frozen conditions. In order to investigate the effect on the free radon production rate of uranium tailings under frozen and non-frozen conditions, uranium tailings from southern China were selected for screening, and temperature, water–solid mass ratio and particle size were used as influencing factors for research. The stable radon concentration and the free radon production rate of uranium tailings of varying particle sizes at different temperatures (20 °C, 0 °C, − 10 °C, − 20 °C) and different water–solid mass ratios (0, 0.14, 0.28) were measured by the homemade radon collection tanks. The experimental results showed that: (1) The free radon production rate decreases with temperature decreases, more significantly under frozen conditions, dropping 3.49–4.16% per 1 °C on average. (2) Under non-frozen conditions, the free radon production rate rises with water–solid mass ratio rises, while under frozen conditions, the free radon production rate of uranium tailings first increases and then decreases with the increase of water–solid mass ratio. (3) The larger particle size, the lower the free radon production rate. The free radon production rate of uranium tailings with particle size > 450 μm is 21.3–81.1% lower than that of uranium tailings with other particle sizes.

The removal of Cs and Sr from high level radioactive waste is very important for ecological protection. However, simultaneous immobilization of Cs and Sr is rarely reported. In this work, a perovskite structure CsSr₂Ta₃O₁₀ was synthesized by molten salt method. CsSr₂Ta₃O₁₀ has good thermal stability up to 900 °C at least. Under the γ irradiation of Co-60, most of the material maintained its structural integrity. CsSr₂Ta₃O₁₀ demonstrates a wide range of pH durability, where Cs is stable in the pH range from 4 to 12 and Sr from 2 to 12. Its frame structure remains stable in the pH range from 2 to 12 and will not be decomposed. Further sintering of CsSr₂Ta₃O₁₀ ceramic waste forms results in a high density of 93% − 95%. Moreover, leaching experiments conclude that the long-term leaching rates of Cs and Sr begin to stabilize after 14 days, reaching the order of 10⁰ and 10⁻³ g·m⁻²·d⁻¹. These results provide a possibility for the simultaneous immobilization of Cs and Sr.

The study evaluated the presence of anthropogenic and natural radionuclides in wheat samples close to nuclear facilities of Dera Ghazi Khan by using gamma ray spectrometry. The average activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K found to be 1.60, 2.41 and 108.22 Bq/kg, respectively. The estimated average values for the internal hazard index, radium equivalent, radiological doses and cancer risk factor were found to be within acceptable ranges. The study discovered no substantial health concerns from consuming edible grains because their concentrations were within the permissible limits established by UNSCEAR.

Graphical abstract

The separation of ²⁴¹Am, ²⁴⁴Cm and ²⁴⁹Cf from rare earth elements using LN resin and lactate buffer solutions with diethylenetriaminepentaacetic acid is described with numerous columns studies. The elutions are based on TALSPEAK liquid–liquid extraction chemistry, and provide high yield (> 90%), rapid, simple separations of the trivalent actinides from the lanthanides, which is often challenging due to similarities in chemical behavior among the trivalent f-block elements. All three actinides can be separated from rare earth elements, including from massless fission product samples and samples with small amounts (~ 1–5 mg) of stable lanthanides. Separations with no detectable overlap between the actinide and lanthanide elutions is possible with massless samples, and in samples with mass high separation factors can be achieved (Am/Eu: 171; Am/La: 10⁶).