Simultaneous determination of actinides and 90Sr in large-size soil and sediment samples

Comparison for the simultaneous determination of 237Np and Pu isotopes between TEVA and TK200 resin

A reliable and stable method was developed to accurately analyze neptunium (237Np) and plutonium isotopes in environmental samples using 242Pu or 236Pu as a tracer. Key parameters, including the valence adjustment conditions and the stabilities of Pu and Np in the different resins, were investigated using TK200 and TEVA resin. It was found that Pu and Np could be efficiently extracted simultaneously using TK200 resin under the optimal loading conditions (6-12 M HNO3) with the addition of 0.01-0.12 M NaNO2 for valence adjustment. These isotopes were subsequently stripped out using a solution containing 0.1 M HCl, 0.05 M HF, and 0.01 M NH2OH·HCl. The separation efficiencies of Pu and Np were >93%, and the chemical yield ratio between Np and Pu was maintained steady at an average of 1.00 ± 0.03 (n > 50) under the optimal conditions. The analytical method was validated by analyzing environmental soil samples spiked with known amounts of 239Pu and 237Np standard solutions or certified reference materials. The measured values of 237Np, 239Pu, and 240Pu obtained by inductively coupled plasma tandem mass spectrometry were consistent with their International Atomic Energy Agency literature values within a 95% confidence interval. These results confirm the reliability and high analytical precision (<6%) of this developed method using Pu as a non-isotopic tracer for monitoring the chemical yield of 237Np. The developed method can also be used for environmental pollutant monitoring and for tracer studies of the 237Np and Pu isotopes.

Highly efficient separation of Am(III) and Pu(IV) from lean feeds and soil using an extraction chromatographic resin containing a diglycolamide in an ionic liquid

A TODGA based extraction chromatographic resin containing an ionic liquid was used for the separation of actinide ions such as Am3+ and Pu4+ from samples such as lean effluents emanating from laboratory waste, environmental water as well as soil samples adjacent to a nuclear plant site. The methodology involved feed adjustment to 3 M HNO3 followed by conditioning of the column, loading, washing (3 M HNO3), and elution of the actinide ions. The elution of Am3+ was done using EDTA in a buffered medium (1 M guanidine carbonate) while that of Pu4+ was carried out using a mixture of 0.5 M oxalic acid and 0.5 M HNO3. The elution peaks were sharp with almost no tailing suggesting the efficiency of the separation method. The results obtained were compared with the literature results which suggested the high efficiency of the present method.

Investigation of the chemical and radiation stability of titanium dioxide with surface arsenate groups during 90Sr adsorption

The chemical and radiation stability of titanium dioxide with surface arsenate groups during ⁹⁰Sr adsorption has been studied. The oxalate technique has been used to obtain a solution containing ⁹⁰Sr from the objects of the aquatic environment of the Chornobyl Exclusion Zone. The dependence of the strontium adsorption on the acidity of the solution and the initial activity of the solution (Bq per mL) has been shown. SEM, XRF, and EDS spectroscopy confirm the chemical resistance of 4As-TiO₂ during regeneration. According to the study with ⁹⁰Sr, the decrease in the adsorption capacity of 4As-TiO₂ during regeneration is associated with incomplete leaching of strontium from 4As-TiO₂ micropores. Using an electron accelerator, the radiation resistance of titanium dioxide with surface arsenate groups to β^- -particles with an energy of 1 MeV has been studied. The invariability of the elemental composition and adsorption properties of 4As-TiO₂ at irradiation doses of 5·10⁷Sv testifies to the high radiation resistance of 4As-TiO₂. The result obtained indicates the promise of 4As-TiO₂ for improving radiochemical methods.

Determination of 241Am in Environmental Samples: A Review

The determination of ²⁴¹Am in the environment is of importance in monitoring its release and assessing its environmental impact and radiological risk. This paper aims to give an overview about the recent developments and the state-of-art analytical methods for ²⁴¹Am determination in environmental samples. Thorough discussions are given in this paper covering a wide range of aspects, including sample pre-treatment and pre-concentration methods, chemical separation techniques, source preparation, radiometric and mass spectrometric measurement techniques, speciation analyses, and tracer applications. The paper focuses on some hyphenated separation methods based on different chromatographic resins, which have been developed to achieve high analytical efficiency and sample throughput for the determination of ²⁴¹Am. The performances of different radiometric and mass spectrometric measurement techniques for ²⁴¹Am are evaluated and compared. Tracer applications of ²⁴¹Am in the environment, including speciation analyses of ²⁴¹Am, and applications in nuclear forensics are also discussed.