Volume 112, Issue 3

Excitation functions for the formation of the radionuclides 51 Cr, 52 Mn and 54 Mn via deuteron-induced activation of natural iron were measured up to deuteron energies of 35 MeV. The available experimental databases of the reaction products 51 Cr, 52 Mn and 54 Mn were extended and compared with the nuclear model calculations using the TALYS code. The model calculations reproduce our measured data after a careful choice of the input model parameters. Some information obtained on competition between the emission of multinucleons and a bound α-particle.

Literature reports have demonstrated that Schiff-base-type ligands can serve as robust platforms for the synthesis of heterobimetallic complexes containing transition metals and the uranyl dication (UO 2 2+ ). However, efforts have not advanced to include either synthesis of complexes containing second- or third-row transition metals or measurement of the redox properties of the corresponding heterobimetallic complexes, despite the significance of actinide redox in studies of nuclear fuel reprocessing and separations. Here, metalloligands denoted [Ni], [Pd], and [Pt] that contain the corresponding Group 10 metals have been prepared and a synthetic strategy to access species incorporating the uranyl ion (UO 2 2+ ) has been explored, toward the goal of understanding how the secondary metals could tune uranium-centered redox chemistry. The synthesis and redox characterization of the bimetallic complex [Ni,UO 2 ] was achieved, and factors that appear to govern extension of the chosen synthetic strategy to complexes with Pd and Pt are reported here. Infrared and solid-state structural data from X-ray diffraction analysis of the metalloligands [Pd] and [Pt] show that the metal centers in these complexes adopt the expected square planar geometries, while the structure of the bimetallic [Ni,UO 2 ] reveals that the uranyl moiety influences the coordination environment of Ni(II), including inducement of a puckering of the ligand backbone of the complex in which the phenyl rings fold around the nickel-containing core in an umbrella-shaped fashion. Cyclic voltammetric data collected on the heterobimetallic complexes of both Ni(II) and Pd(II) provide evidence for uranium-centered redox cycling, as well as for the accessibility of other reductions that could be associated with Ni(II) or the organic ligand backbone. Taken together, these results highlight the unique redox behaviors that can be observed in multimetallic systems and design concepts that could be useful for accessing tunable multimetallic complexes containing the uranyl dication.

An innovative phytic acid modified reed straw-derived hydrochar composite (PA-C-RBC) was prepared by using inexpensive reed straw and non-toxic phytic acid for the removal of uranium(VI) from aqueous environment. Several characterization results showed that PA-C-RBC was rough and porous with a large number of hydroxyl, carboxyl, and phosphate groups. The uranium(VI) adsorption process by PA-C-RBC conformed to pseudo-second-order kinetic and Langmuir models, and the theoretical maximal adsorption capacity could attain 418.78 mg/g at pH 5.0. PA-C-RBC had 72.66 % of selectivity and 6772.99 mL/g of distribution coefficient for U(VI). Due to the strong chelating between the hydroxyl and phosphate groups on PA-C-RBC and U(VI), PA-C-RBC had excellent adsorption selectivity. These finding highlighted a high potential for removing U(VI) from aqueous solutions.

The production method of no-carrier added Lutetium-177 ( 177 Lu) was developed from a neutron-activated natural ytterbium (Yb) using column chromatography separation method. Dowex W50 X8 resin and a combination of alpha-hydroxyisobutyric acid (α-HIBA) and hydrochloric acid (HCl) were used as column filler and eluent, respectively. HCl increased the desorption and separation between 177 Lu and Yb at a concentration of 0.25 M, while the optimal α-HIBA concentration was 0.15 M, resulting in 177 Lu yield of 81.19 % and low impurities ( 175 Yb: 9.28 %, and 169 Yb: 2.09 %). Nevertheless, further study using an enriched 176 Yb target is essential to significantly increase the specific activity of 177 Lu.

This report unveils the outcomes of measurements of 222 Rn exhalation rates, effective 226 Ra content, and the annual effective dose for rocks and soil collected in the vicinity and far from the seismically active Kopili Fault Zone, India. LR-115 (II) nuclear track detector has been used to investigate radiation exposure in the seismically active fault zone and gneissic complex of the Shillong Plateau, which have significant geological characteristics and frequently produce earthquakes. In this study, 222 Rn mass exhalation rates for granite, gneiss, and soil samples collected near and far from the fault were calculated to be in the ranges of 73.2–83.0, 11.0–14.8, 21.1–70.7 and 34.3–65.5, 6.4–9.9, 19.1–28.9 mBq kg −1  h −1 , respectively. Surface exhalation rates of 222 Rn for granite, gneiss, and soil samples collected near and far from the fault varied between 2428.8–2751.7, 365.6–491.9, 698.3–2345.9, and 1138.6–2172.7, 211.9–328.2, 634.9–960.0 mBq m −2  h −1 , respectively. The 226 Ra contents of granite, gneiss, and soil collected in similar distributions were found to vary from 9.76–11.06, 1.47–1.98, 2.8–9.4, and 4.58–8.74, 0.85–1.32, 2.6–3.6 Bq kg −1 , respectively. The annual effective doses attributed to 222 Rn inhalation from exposure to the samples were calculated to be in the ranges of 176.3–199.8, 26.5–35.7, 50.7–170.3 and 82.7–157.7, 15.4–23.8, 46.1–69.7 μSv y −1 , respectively, for granite, gneiss, and soil. The lifetime fatality-risks have also been analysed in this study. The samples that were collected in close proximity to the fault showed higher values than those that were collected farther away. However, the results reveal that the measured values are within the globally recognised permissible range.

When operating and dismantling a nuclear facility that handles uranium, the surrounding soil may be contaminated, emphasizing the need for appropriate treatment and disposal methods for soil waste. This study assessed high-temperature sintering technology for uranium contaminated soil waste to overcome limitations in existing decontamination methods and the volume increase associated with current solidification technology. The sintering process was found to effectively vitrify and re-mineralize complex chemical components in the soil. Sintered bodies were produced under varying conditions, adjusting molding pressure, heating temperature, and time. Optimized conditions resulted in sintered bodies with a volume reduction rate exceeding 30 % and a compressive strength surpassing 10 MPa, indicating a significant impact on the phase conversion and re-mineralization of silt and clay minerals. The soil sintering mechanism was identified through comprehensive microscopic observations and mineral phase change analysis. Leaching evaluations of sintered bodies, made from simulated uranium-contaminated soil, demonstrated their applicability to contaminated soil wastes. Additionally, it was confirmed that the sintering temperature of the soil could be lowered by incorporating a small amount of B 2 O 3 , suggesting a means to enhance the economic feasibility of the treatment process. The findings of this study highlight the applicability of pressureless sintering technology, based on glass composite materials, capable of simultaneously reducing and stabilizing uranium-contaminated soil waste.

The current work deals with studying the influence of cheap, widespread CaO on improving the γ ray-protection capacity of the lightweight, sealing polyester. Therefore, polyester composites were filled with different concentrations of CaO fillers. The fabricated CaO-reinforced polyester composites’ density ranged between 1.177 g/cm 3 and 1.377 g/cm 3 , when CaO filler concentrations increased between 0 wt% and 60 wt%, respectively. Fabricated composites’ morphology and chemical composition, as well as CaO fillers’ grain size and distribution, were proved using SEM and EDX spectroscopy. Additionally, the influence of CaO fillers on the gamma-ray shielding properties of the fabricated composites was evaluated using the Monte Carlo simulation and confirmed using the experimental measurements. The recorded results show an enhancement in the synthesized composites’ linear attenuation coefficient from 0.091 cm −1 to 0.106 cm −1 at a gamma ray energy of 0.662 MeV. Moreover, the excess in CaO concentration from 0 wt% and 60 wt% reduces the fabricated composites’ half-value thickness values from 7.64 cm to 6.51 cm, respectively.