Volume 113, Issue 6

The plutonium in the highly radioactive waste liquid has a long half-life and this persistent radioactivity poses a great challenge to the long-term geological disposal of nuclear waste, making it necessary to separate it from other elements. Herein, three amide functionalized imidazolium ionic liquids (DXZ-1, DXZ-2 and MIMDIDOA) were synthesized for separation of Pu(IV) (Th(IV) used as a surrogate for plutonium) from a high-concentration nitric acid solution. The findings revealed that under the condition of 8 mol/L nitric acid, the kerosene solution with 0.1 mol/L MIMDIDOA has the highest extraction efficiency for Th(IV), with SF Th/U of 5.85, while the extraction of lanthanides (lanthanum and europium) can be ignored. The extraction mechanism was elucidated through Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The extraction process is an anion exchange process between chloride ions and thorium complex anions in solution assisted by N-containing functional groups in ionic liquids. The adsorption recovery rate of Th 4+ / 242 Pu 4+ by the extraction-elution resin impregnated using MIMDIDOA can reach 81 % under experimental conditions.

Spectrum-averaged cross sections of the reactions 85 Rb(n,α) 82xm + g Br, 85 Rb(n,2n) 84xm + g Rb and 85 Rb(n,p) 85m Kr were measured over the fast neutron spectrum with neutron energies from 0.5 to 20 MeV of a TRIGA reactor. In addition, data for the well-investigated reactions 113 In(n,n´) 113m In and 115 In(n,n´) 115m In were re-measured to confirm the validity of the neutron spectrum and the experimental techniques. The new results of the present measurements were used to perform integral tests of evaluated excitation functions in the latest nuclear data libraries, including ENDF/B-VIII.1, JEFF-3.3, JEFF-3.1/A, JENDL-5, IRDF-1.05, and TENDL-2023. The experimental data generally agree with the integrated values from the excitation functions within 8 %, with a few exceptions. For the reaction 85 Rb(n,2n) 84xm + g Rb, the integrated value from the ENDF/B-VIII.1 library is higher by 17 % than the measured integral value. The JEFF-3.1/A and JENDL-5 libraries for the reaction 85 Rb(n,p) 85m Kr appear to require improvement.

Terbium-161 ( 161 Tb) is emerging as a promising radionuclide for cancer therapy due to its favorable nuclear properties that are similar to clinically established lutetium-177 ( 177 Lu) along with its therapeutic edge arising from the higher number of Auger and conversion electrons per decay. These low energy electrons result in higher cytotoxicity within a short range of the decaying nuclei to enhance therapeutic efficacy. Despite these promising characteristics, a significant challenge remains in the lack of a domestic 161 Tb supply in the United States, which poses an obstacle to the advancement of 161 Tb-based radiopharmaceutical research and development. This study developed a reliable cation-exchange high-performance liquid chromatography-based method for purification of reactor-produced 161 Tb at quantities suitable to support research and preclinical studies. The purified 161 Tb product showed high radionuclidic purity with excellent radiochemical purity, and the successful labeling studies with the DOTA chelator and DOTA-TATE peptide demonstrated the effective incorporation of the purified 161 Tb into radiopharmaceuticals designed for targeted cancer therapy.

Shewanella azerbaijanica can transfer electrons to uranium in its respiratory system and maintain the efficient growth through bioreduction process. MtrABDEF are some of the main cytochromes involving in Extracellular Electron Transfer of Shewanella . This work attempts to investigate how these genes are affected by various respiratory conditions, and make an effort to enhance their expression through a series of incubations at increasing uranium concentrations. Mtr gene expressions and the uranium removal were analyzed by Real Time RT-PCR and ICP-AES respectively. Uranium threshold concentration, (1 mM uranium for anaerobic electron donor free samples, and 2 mM uranium for electron donor containing samples), the ratio of electron donor to electron acceptor, and the presence of Oxygen, were found to be some of the most important factors affecting the mtr gene expressions during bioreduction. During the acclimation procedure mtr gene expressions were well enhanced, demonstrating that acclimation is a suitable strategy to improve Mtr pathway. Less uranium removal percentage by acclimated bacteria, however, indicates that mtrABDEF are not the most significant agents in bacterial uranium respiration. This work can serve as a model for more advanced research in uranium bioreduction and acclimation-based reduction improvement.

This study aims to investigate radon (Rn-222) gas concentrations in soil and water within seismic-prone regions of Peja and Vitia, Kosovo. The study utilizes the Alpha GUARD PQ2000 PRO equipment for precise measurement, based on the primary and some secondary data gathered. The observed soil gas radon concentrations ranged from 34.6 kBq/m 3 to 130.4 kBq/m 3 in Peja and 19.8 kBq/m 3 to 73.2 kBq/m 3 in Vitia, amidst minor seismic events with magnitudes between 1.5 and 2.6. The epicenters are located at distances ranging from 3.1 to 38 km from the radon monitoring sites. The seasonal correction factor was 0.98 for the dry season and 1.01 for the wet season for both areas (Peja and Vitia). Concurrently, radon activity concentrations in spring water varied from 5.7 Bq/L to 9.6 Bq/L in Peja and from 212.8 Bq/L to 275.3 Bq/L in Vitia. These findings emphasize the potential of radon monitoring as an earthquake precursor and highlight the influence of meteorological factors on radon levels, paving the way for future research in earthquake forecasting and environmental safety. Notably, the soil radon levels decrease during heavy rainfall.This contributes to understanding radon’s behavior under varying environmental conditions.

Aluminum–boron alloys with different boron contents have been fabricated using the stir-casting technique. A comparative research was done to determine the optimal radiation shielding parameters for the synthesized metal alloys. The radiation shielding parameters obtained include the linear attenuation coefficient ( μ ), total mass attenuation coefficient (MAC), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), effective atomic number ( Z eff ), electron density number ( N eff ), and absorbed dose rate (Dr). Theoretical findings were derived using web-based tools, the Phy-X/PSD and Py-MLBUF software, and were interpolated at specific energy levels. Reasonable agreement was observed, and the variance between experimental MAC and theoretical values with relative deviations (|RD|%) were ranged from 1.39 to 8.94 %. The highest values for the fast neutron removal cross-section (FNRC) and the macroscopic cross-section (MRCS), for S5 are 0.104 and 0.119, respectively. The range of H + , He +2 , Ti +4 , Bi +5 , and Dy +3 ions through the investigated alloys was computed with the SRIM Monte Carlo software in a wide energy range from 0.01 to 20 MeV. The ESTAR NIST program calculated the total stopping power (TSP) and range ( R ) values for electron interactions over the 10 −2 –10 3  MeV energy range. At the 20 MeV ions, energy through the investigated alloys target the ascending order of ions range is R Bi+5 < R Dy+3 < R Ti+4 < R He+2 < R H+. As the electron energy increased, S1, which has the highest density, gave the highest TSP. The CSDA range of the electrons was higher in low density sample.

Lead-borate glasses with Eu, Y, La, or Sm oxides were investigated for their radiation shielding capabilities across a broad range of energies. Due to the glasses’ varying content, each sample had varying densities, with the Sm glass having the highest density and the Y glass having the least. At lower energies, the MAC values followed the Y 2 O 3  < La 2 O 3  < Sm 2 O 3  < Eu 2 O 3 order, while at higher energies the MACs are practically identical. The glasses’ LACs showed an inverse energy relationship, such as those of the Y glass which are 0.946, 0.439, and 0.293 cm −1 at 0.284, 0.511, and 0.826 MeV, respectively. The Z eff of the glasses are in the order of Eu > Sm > La > Y, which corresponds to the relative order of the sample-based additives’ atomic numbers. The RPEs of the glasses revealed the Sm glass to have slightly greater protection efficiency than the Eu glass, while increasing the thickness of the sample greatly improved the shielding effectiveness. The ratio of the reference glass’s HVL to each of a set of compared glasses’ LAC showed that the Sm glass is a viable glass for radiation shielding applications.