Laboratory-based X-ray spectrometer for actinide science

X-ray absorption and emission spectroscopies nowadays are advanced characterization methods for fundamental and applied actinide research. One of the advantages of these methods is to reveal slight changes in the structural and electronic properties of radionuclides. The experiments are generally carried out at synchrotrons. However, considerable progress has been made to construct laboratory-based X-ray spectrometers for X-ray absorption and emission spectroscopies. Laboratory spectrometers are reliable, effective and accessible alternatives to synchrotrons, especially for actinide research, which allow dispensing with high costs of the radioactive sample transport and synchrotron time. Moreover, data from laboratory spectrometers, obtained within a reasonable time, are comparable with synchrotron results. Thereby, laboratory spectrometers can complement synchrotrons or can be used for preliminary experiments to find perspective samples for synchrotron experiments with better resolution. Here, the construction and implementation of an X-ray spectrometer (LomonosovXAS) in Johann-geometry at a radiochemistry laboratory is reported. Examples are given of the application of LomonosovXAS to actinide systems relevant to the chemistry of f-elements, the physical chemistry of nuclear power engineering and the long-term disposal of spent nuclear fuel.

New tetradentate N,O-hybrid phenanthroline-derived organophosphorus extractants for the separation and complexation of trivalent actinides and lanthanides

Comparison of the extraction and separation properties between two novel phenanthroline-derived organophosphorus ligands, Et-Ph-BPPhen and Et-Ph-PIPhen.

PyRad: A software shell for simulating radiolysis with Qball package

The assessment of the radiolytic stability of media is an important task in the fields of nuclear power engineering and radiochemistry. Such studies must be carried out in special laboratory conditions with the use of sources of ionizing radiation, which may increase personal doses of the staff. In addition, difficulties arise in studying the products of irradiated media. While it is impossible to abandon experiments to obtain reliable results in this area, computational methods of quantum chemistry can reduce the number of experiments and help understand the mechanisms of the reactions that occur during radiolysis. Here we would like to present a software shell of the Qb@ll program performing time-dependent density functional theory simulations of the radiolysis process.

A search of a quantitative quantum-chemical approach for radiolytic stability prediction

Radiolytic stability is one of the main requirements of the substances that are used in the chemistry of nuclear cycle or in the radiopharmaceutical chemistry. Herein, we proposed an approach for the prediction of radiolytic stability by the estimation of the molecular reactivity. The DFT calculations of the atom-wise reactivity descriptor were made for a number of organic molecules. The theoretical simulations were validated by the experimental data. We irradiated the molecules by gamma-radiation and studied the products of radiolysis and changes in the molecular concentration by HPLC-MS analysis. The importance of the inclusion of the conformational influence and the steric accessibility in the calculation is shown in this study. We presente a new chemical reactivity descriptor (CRD) and recommend using CRD as the new quantitative estimation of the reactivity. A good correlation between the CRD and the constants of the radiolysis was obtained.