This study investigates the relationship between the range of alpha particles and the specific activity of radionuclides in the uranium decay series. An explicit analytical correlation between radionuclide specific activity and alpha-particle range in air was derived by combining Royer’s alpha-decay systematics, the definition of specific activity, and the empirical range–energy relationship. Calculations were performed for selected alpha-emitting radionuclides of the uranium decay series. The obtained ranges were compared with ASTAR reference data, SRIM-2013 simulations, and published experimental measurements. The analytical estimates showed good overall agreement with the reference and experimental datasets. Comparison with nine published experimental range values yielded a mean absolute relative difference of approximately 3.65
This note offers an alternative interpretation of the data presented in Kumar et al. [1]. In that study, polymer-based Bakelite resistive plate chamber detectors were exposed to a 60Co gamma source at various irradiation doses. Analyzing the results from multiple characterization techniques—FTIR, XRD, and conductivity—the authors concluded that cross-linking dominates above 100 kGy, while degradation predominates below 80 kGy. Here, we present a different interpretation of their results, which leads to a revised final conclusion. Additionally, we propose an alternative mechanism for Bakelite modification under gamma irradiation. The mechanism suggested by Kumar et al. implies a carbon atom forming five covalent bonds, a rare scenario. Based on the analysis results reported in their work, we propose a new mechanism and associated structural interpretation.
The safe and efficient treatment of rubber-based wastes from nuclear facilities has become an increasingly pressing challenge with the continued expansion of the global nuclear power industry. In this study, the reaction characteristics and mechanistic pathways of an acid digestion–based wet combustion process for radioactive nitrile butadiene rubber (NBR) waste were systematically investigated. Comprehensive characterization using SEM, FT-IR, XRD, EA, TGA, and GC–MS, combined with density functional theory (DFT)-based reaction enthalpy calculations, was employed to elucidate the structural evolution and thermodynamic characteristics during acid digestion. The results demonstrated that concentrated sulfuric acid carbonization disrupted the crosslinked rubber network and generated highly reactive carbonaceous intermediates, which were subsequently subjected to deep oxidation by nitric acid. Under the optimized experimental conditions within the investigated range (250 °C, HNO₃/H₂SO₄ = 3:10, and 3 h oxidation), the acid digestion process achieved a near-complete degradation performance, with a weight loss ratio exceeding 99
Successful demonstration of laser-driven nuclear reactions, resulting in synthesis of medical radioisotopes has been repeatedly reported. However, the obtained activities in these experiments are orders of magnitude lower compared to what is needed for practical applications. Here we discuss the steps which are required for the optimization of the laser-driven production of ^11 C using nuclear reactions on solid boron targets. The proposed experiments for optimization of the secondary proton/deuteron beams are introduced. The reported reaction cross sections for production of ^11 C on boron targets are critically assessed. The reported radioisotope production estimates are benchmarked by exploring the ^11 C activities delivered at a proton cyclotron. Important parameters in the production process are the physical and chemical conditions of the production targets which are also discussed here.
An advanced inorganic cobalt aluminum silico tungstate (CoAlSiW) sorbent was successfully synthesized and subsequently applied for the selective elimination of radioactive cesium and strontium ions from real liquid radioactive waste streams. CoAlSiW was characterized using diverse analytical techniques to reveal its structure, surface morphology, and physicochemical features. Studies on batch adsorption were conducted to evaluate the impacts of pH, contact time, initial ion concentration, and temperature on the sorption performance. The adsorption of Cs(I) and Sr(II) follows Freundlich isotherm model, confirming heterogeneous surface characteristics and favorable multilayer sorption behavior. According to thermodynamics, the process is spontaneous and energetically favorable. Importantly, the impact of gamma irradiation was evaluated, confirming the material’s high radiation stability and resistance, with no significant loss of sorption efficiency. Dynamic column breakthrough experiments further highlighted high sorption capacities of 78 mg g−1 for Sr(II) and 72 mg g−1 for Cs(I). The applicability of CoAlSiW for real radioactive waste treatment was confirmed by its high removal efficiency toward 137Cs (92.6
This study investigates the spatio-temporal variations in stable isotopes (δD and δ18O) of precipitation within the topographically complex Qinghai-Tibet Plateau transition zone to understand regional precipitation patterns and influencing factors. Precipitation samples were collected across the region and analyzed. Due to high relief, the study area was divided into three sub-basins based on basin delineation. The HYSPLIT model was employed to identify water vapor sources. Additionally, the applicability of the C-Isoscape and OIPC isotope datasets was evaluated. Results show: (1) δD and δ18O exhibit significant spatio-temporal fluctuation, which are statistically significant but of small amplitude; (2) Despite similar altitudes, significant isotopic differences exist between sub-basins, attributed to pronounced subcloud evaporation during the rainy season; (3) While isotopically enriched westerly moisture contributes, vapor from neighboring regions with distinct isotopic characteristics is the dominant source; (4) Both C-Isoscape and OIPC datasets performed poorly in the study area but offer valuable reference data where sampling is challenging. We conclude that the complexity of isotopic variations arises primarily from variable vapor sources and local processes like subcloud evaporation, exacerbated by topography. This work provides critical insights into the regional hydrology and a reference for isotope studies in complex transition zones.
Preferential leaching of 224Ra from ThO2 in nitric acid was investigated to develop a simple 224Ra production method for targeted alpha therapy. Finely ground ThO2 was immersed in 0.1–6 M HNO3 for up to 20 days, and leachate samples were periodically collected and analyzed for 224Ra, 228Ac (in equilibrium with 228Ra), and 232Th. 224Ra activity increased by 2.0–3.5 times from the initial measurement, reaching an apparent leaching ratio of 33–47
A new sandstone-type uranium deposit was discovered in the Longchuanjiang Basin as uranium exploration continued. This article employs mineralogical and geochemical techniques to investigate the paleoenvironment, provenance, and tectonic setting of the newly identified mineral deposit while also examining its mineralization process. The Zr, ICV, and Zr/Sc-Th/Sc diagrams suggest that the Mangbang Formation has experienced multiple sedimentary cycles. The δCe-δEu, δCe-∑REE, and δCe-(Dy/Sm)N diagrams of the samples suggest that the chemical composition of the samples was marginally influenced by diagenesis, making them suitable for the investigation of paleoenvironments and provenance. The Sr, CIA, CIAcorr, Rb/Sr, V/Cr, U/Th, (Cu+Mo)/Zn, and Ni/Co ratios indicate that the Mangbang Formation exhibits oxidative conditions, with certain portions transitioning to oxidation–reduction conditions and freshwater deposits in a warm and humid environment. Al2O3/TiO2, TiO2/Zr ratios, and Co/Th-La/Sc, La/Th-Hf, REE-La/Yb, SiO2-K2O/Na2O, Fe2O3T+MgO-TiO2, Th-Co-Zr/10, and Th-Sc Zr/10 diagrams indicate the provenance of the Mangbang Formation is a mixture of felsic igneous rocks and granite, within an active continental margin setting associated with the closure of the Paleo-Tethys Ocean. During the sedimentary stage, there was pre-enrichment of uranium in the Mangbang Formation. The pre-enrichment of uranium is similar to that of Cd and Mo and is related to oxidation–reduction conditions and the clay minerals, but different from Ga. During the post-sedimentary stage, the uranium and oxygen-rich water migrate along the strata, activating the pre-enriched uranium and ultimately reducing and precipitating near the oxidation–reduction front. Through the ongoing processes of oxidation, migration, and precipitation, uranium accumulates and ultimately forms sandstone-type uranium deposits that can be industrially mined.
Non-fission-produced iodine-131 was comprehensively evaluated through preclinical investigations encompassing stability, biodistribution, pharmacokinetics, dosimetry, and toxicity. Oral iodine-131 demonstrated stability over 32 days, along with rapid and sustained thyroid accumulation, predominantly renal clearance, and minimal uptake in non-target organs. Pharmacokinetic analysis indicated high bioavailability, extensive systemic distribution, prolonged blood residence, and relatively slow clearance, suggesting sustained circulation and progressive organ uptake. Organ dosimetry showed a heterogeneous distribution pattern dominated by thyroid dose, with additional contributions in excretory and highly perfused organs. Toxicological assessments revealed no mortality, significant toxicity, hematological abnormalities, or major histopathological alterations, with only minimal lesions observed at higher dose levels. Collectively, these findings demonstrate that locally produced non-fission iodine-131 possesses favorable efficacy, biodistribution, dosimetry properties, and safety characteristics, supporting its promise for diagnostic and therapeutic applications for thyroid disorders treatment.
In this study, research on a series of characteristics was conducted using an EJ276 plastic scintillation detector. Good pulse shape discrimination has been obtained using a 241Am–Be radioactive source, and the figure of merit is 1.27. The Birks function was determined through gamma-ray energy calibration, neutron energy calibration, light output resolution function calibration, and GEANT4 Monte Carlo simulation. Finally, the Unfolding based on Genetic Algorithm software was used to solve the neutron spectrum of the 241Am–Be source, and the measurement error of the neutron fluence rate was calculated to be −22.0
The treatment of uranium-containing wastewater faces major challenges, including complex compositions, strong interference from coexisting ions, poor selectivity of conventional methods, and rapid blockage of electrode active sites. Here, we utilize expired flour as a low-cost biomass carbon/nitrogen source and copper oxalate as a copper precursor to prepare a biomass-derived carbon-supported copper single-atom catalyst (Cu-SAs/BC). This catalyst is then composited with g-C3N4 at an optimal mass ratio of 2:3 and loaded onto carbon felt to construct a Cu-SAs/BC-g-C3N4 photoelectrocatalytic electrode. The electrode achieves a uranium removal efficiency of 99.4
The determination of uranium at trace levels (parts per billion, ppb) in nitrate-rich matrices by luminescence techniques is challenging due to severe matrix interference and luminescence quenching effects caused by nitrate ions. In this study, we introduce a novel chemical reaction between sodium nitrate and orthophosphoric acid that transforms a nitrate matrix into a phosphate matrix. Complete conversion of sodium nitrate was achieved by heating with H3PO4 at 175 °C. UV–Vis spectroscopy confirmed the complete disappearance of nitrate absorption bands, while powder X-ray diffraction, FTIR spectroscopy, and ICP–OES analyses established the formation of amorphous disodium pyrophosphate (Na2H2P2O7). Elimination of nitrate-induced quenching resulted in a marked enhancement of uranyl luminescence, enabling a linear analytical response over the concentration range of 5–2500 ng g−1 with a detection limit of 0.6 ng g−1. Overall, the proposed approach provides a straightforward, efficient, and matrix-tolerant pathway for luminescence-based uranium analysis, with potential applications in nuclear fuel processing, environmental monitoring, and radiochemical analysis.
As a high mass ‘wing’ fission product, the cumulative fission yield (CFY) of 156Eu varies both with incident neutron energy and actinide isotope undergoing fission. Fission product 155Eu should yield comparable information to that of 156Eu long after this shorter half-life radioisotope has decayed (half-life of 4.75 years versus 15.19 days). In this context a series of solid Eu2O3 mounts previously prepared for the measurement of 156Eu have been reanalyzed for 155Eu. Samples generated from the separation of europium from dissolved Highly Enriched Uranium (HEU) targets irradiated by thermal neutrons were used for technique development, with gamma-ray spectrometry proving to be an effective measurement technique. Utilizing this method two complimentary analyses paths were developed and then successfully applied to the measurement of sample sets where either the incident neutron and/or actinide fuels were varied. As would be expected, if the measurements were accurate and precise, 155Eu fission yields varied in a predictable fashion with both neutron energy and actinide fuel. As further validation of the technique, the increased perturbation away from thermal fission yields as the cumulative fission yield mass chain increases was also observed (153<155<156). This was evidenced through comparison with prior analysis results for 153Sm and 156Eu. 155Eu can thus be measured with a high degree of confidence in samples where both these shorter half-life radioisotopes have decayed.
Naturally occurring radioactive material (NORM), particularly Ra-226 and Ra-228, accumulates in oil-production scales and associated brines, creating radiological, environmental, and waste-management challenges. Radium removal from high-salinity systems is complicated by competition from Ba2+, Sr2+, and Ca2+ and by sulfate-driven co-precipitation. Scale leachates were treated in synthetic brines up to 85 g/L total dissolved solids using functionalized GO-coated titanium electrodes in a batch electrochemical reactor. The effects of pH, salinity, applied potential, contact time, initial radium activity, and barium concentration were examined. Ra-226 and Ra-228 were quantified by HPGe gamma spectrometry using geometry- and density-matched calibration and equilibrium controls, and aqueous speciation and precipitation tendencies were modeled in PHREEQC. Under the optimized operating condition (pH 11.3, 2.5 V, 90 min), apparent removal efficiencies were 83.1
The study of reaction dynamics from 10,11B-induced reactions has been conducted over a wide mass region, where 11B acts as a strongly bound system and 10B behaves as an intermediate between the weakly and strongly bound nuclei. The α-breakup threshold energy of 10B (4.46 MeV) is less than that of the 11B nucleus (8.66 MeV). As a result, 10B shows a dominant contribution from breakup reactions relative to 11B, as reflected in incomplete fusion (ICF) studies. The evidence for the contribution of the ICF reaction has been derived from theoretical analyses of the 10B projectile across a wide range of target masses, from the light 27Al target to the heavy 209Bi target. However, indirect evidence for the ICF reaction is reported only in the heavier-mass region for 11B-induced reactions. In the medium-heavy and heavy-mass regions, reactions with Zr, Ta, Au, and Bi targets, the ICF contribution is interpreted by the authors from comparisons with statistical model calculations. Interestingly, the evidence for the ICF reaction has not been reported in the literature for 11B reactions with Y, Nb, and Tb targets. The absence of the ICF mechanism in those reactions may be due to a higher α-breakup threshold energy for 11B. Apart from the reaction dynamics, 10,11B-induced reactions have been used to produce some medically relevant radionuclides, and the radiochemical separation of these radionuclides from the bulk targets has been reported. This article comprehensively presents the basic physics and possible applications of 10,11B-induced reactions in the energy range below 10 MeV/nucleon.
The reactor production of the theranostic radioisotopes 64Cu and 67Cu from zinc targets was investigated through a combined Monte Carlo and experimental approach. MCNPX simulations showed that the activity of 64Cu reaches 104 MBq g−1 for enriched 64Zn compared to 103 MBq g−1 for natural zinc, while 67Cu exhibited lower buildup due to its smaller cross section and low natural abundance. The calculated results agreed well with experimental measurements, with deviations within 8–14
A metal-free CBT/1,2-aminothiol click chemistry platform was developed for the rapid construction of complex monomeric and dimeric peptide imaging probes. The novel DOTA-CBT reagents were synthesized and enabled HER2-targeted peptide probe assembly within 1 h, followed by efficient [68Ga]Ga labeling to afford new PET tracers with RCYs up to 96
Gamma photon interaction behaviour of three structurally distinct anticancer drugs (Pemetrexed, Capecitabine, and 6-Mercaptopurine) was computationally characterized using MCNPX Monte Carlo simulation to provide preliminary data relevant to radiosterilization considerations. The effective atomic number (Zeff), mass attenuation coefficient (μ/ρ), and half-value layer (HVL) were computed across the 0.015–15 MeV range. In the low-energy photon region, 6-Mercaptopurine exhibited the highest gamma interaction potential owing to its high sulfur content, whereas Capecitabine showed the lowest; the interaction parameters of the three compounds converge near the Co-60 sterilization energy range. UV photostability data were examined as a complementary, independent descriptor, reported half lives indicated higher photostability for Capecitabine (t1/2 ≈ 24h) and lower photostability for 6-Mercaptopurine (t1/2 ≈ 5.5h). The two descriptor sets reflect distinct physical mechanisms and are not interpreted as predictive. The proposed MCNPX-based workflow offers a cost-effective computational approach for preliminary radiological characterization of pharmaceutical compounds.
Field tests of vitreous nuclear waste forms are of high importance in nuclear waste management and require long-term experiments during which the governing mechanisms of glass corrosion can vary. Corrosion of glasses is a complex process evolving with time which is mainly dependent on glass composition and environmental conditions. We analyse the alternations of glass corrosion mechanisms during long-term tests focusing on an idealised model situation of a perfect homogeneous glass surface in contact with unsaturated water solutions and revealing dominant contributions from either ion exchange or hydrolysis with progressing of process. The two long-lasting mechanisms—ion exchange (IEX) and hydrolysis (HL)—control the overall release of radionuclides from the nuclear waste borosilicate glasses in contact with water with typical effective diffusion coefficients for 137Cs via IEX of about 5 × 10–21 m2/s (4.5 × 10–12 cm2/day) and rates for HL of about 100 nm/y in near surface conditions. The consequences of intrinsic self-irradiation of nuclear waste glasses are also discussed.
The efficient separation of strontium from high-level liquid waste is crucial for nuclear waste management. This study investigates the synergistic enhancement of Sr2+ extraction using two open-chain polyether ligands, BPht-14 and BPPT-14, by replacing chloroform with imidazolium-based ionic liquids [Cnmim][NTf2] (n = 4, 6, 8). The effects of pH, contact time, initial concentration, temperature, and IL alkyl chain length on extraction performance were systematically evaluated. The results demonstrate significant enhancement in IL systems, with BPPT-14 achieving 95.2
