This study proposes a non-destructive method for accurately predicting the water content of bentonite using hyperspectral imaging combined with partial least squares regression (PLSR). Hyperspectral data were collected across the visible (400–700 nm) and near-infrared (1300–1600 nm) spectral ranges from bentonite samples with six controlled water content levels (0, 5, 10, 15, 20, and 25 %). Separate PLSR models were developed for the visible (VIS), near-infrared (NIR), and combined VIS + NIR spectral ranges. Among these, the VIS + NIR model demonstrated the highest predictive accuracy, achieving an R2 of 0.9975 and RMSE of 0.4309 %, significantly outperforming models using individual spectral ranges. The enhanced performance of the combined model is attributed to the integration of macroscopic brightness changes captured in the VIS region and water-specific absorption features in the NIR region. This method provides a rapid and reliable approach for water content prediction, offering significant potential for quality control in bentonite buffer material production and other moisture-sensitive industrial applications.
ZHAO Limei1, ZHU Lingjia1, ZHANG Bo1, 2, MA Shihai1, 3
The incinerator in a nuclear fuel reprocessing plant is used for the controlled combustion and harmless treatment of nuclear fuel waste. Technologically, real-time monitoring of key nodal temperatures within the furnace during the combustion process is essential to guide feed control. This ensures the thoroughness of waste combustion while effectively preventing excessively high temperatures that could damage equipment. Compared to reaction equipment in conventional chemical plants, the incinerator in a nuclear fuel reprocessing plant operates in a high-radiation environment with difficult maintenance access. Consequently, real-time temperature monitoring at key furnace nodes presents significant challenges. To address the challenge of being unable to directly measure key temperatures in the nuclear fuel reprocessing plant incinerator using sensors, an ABCHB-LSTM-GAT model (hyperparameter-optimized long short-term memory graph attention network) was proposed in this paper. The data preprocessing module constructs dynamic graph structures using k-nearest neighbors (KNN) graphs. The LSTM-GAT module employs long short-term memory (LSTM) neural networks integrated with graph attention networks (GAT) to handle spatiotemporal dependencies within sequential data. The optimizer module determines the model’s optimal hyperparameters by combining a Bayesian sampling algorithm with an ultra-wideband dynamic pruning mechanism, enhancing both training efficiency and prediction accuracy. Experimental results demonstrate that this model exhibits significant advantages over baseline LSTM and GAT models in terms of both training efficiency and prediction accuracy. During operational engineering processes, it enables precise prediction of internal furnace temperatures, assisting operators in controlling feed rates and effectively monitoring abnormal conditions such as furnace overheating.
ZENG Zhiyun1, XU Xiaochen1, WEN Qinglong2, LIU Zhipeng2, HU Wenjun1
The TOPAZ-Ⅱ thermionic space nuclear reactor, with its compact structure, high power density, and efficient thermionic energy conversion, is an ideal candidate for space-based power supply in deep-space exploration and long-duration missions. To ensure its safe and stable operation under both nominal and off-nominal conditions, a transient analysis methodology for the TOPAZ-Ⅱ thermionic space nuclear reactor system was established based on a modified version of the RELAP5 system code. The method fully incorporated the primary design features of thermionic space nuclear reactors, including detailed physical models of the thermionic fuel elements (TFE), reactor core, NaK-78 coolant loop, and the space-adapted loop radiator system. Temperature reactivity feedback effects of key materials, such as uranium dioxide fuel, molybdenum emitter and collector electrodes, and the zirconium hydride moderator, were explicitly modeled to capture the reactor’s dynamic response characteristics. The developed RELAP5 code was validated through two complementary approaches. First, steady-state simulation results were compared with nominal design parameters of the TOPAZ-Ⅱ reactor. Relative deviations in key thermal-hydraulic indicators, such as core power and coolant inlet/outlet temperatures, were all within 1%, confirming the model’s accuracy and consistency with established reference values. Second, the model’s ability to simulate transient responses was verified against experimental data from the V-71 electrically heated non-nuclear test facility. Under both partial loss-of-flow and power ramp conditions, the calculated temperature response trends matched the test data well, validating the model’s effectiveness in capturing system dynamics. Based on the validated model, two representative accident scenarios were further investigated: A reactivity insertion accident (RIA) caused by unintended rotation of the control drum, and a loss-of-coolant accident (LOCA) triggered by a hypothetical sudden breach. These scenarios reflect critical failure modes under deep-space mission conditions. Simulation results indicate that although the system exhibits positive temperature reactivity feedback, mainly due to the ZrH moderator, the reactor maintains thermal safety margins throughout all transient phases. Specifically, in the most severe RIA case (0.01 $ insertion), peak fuel and emitter temperatures reach approximately 2 600 K and 2 100 K, respectively. For the LOCA scenario caused by complete coolant loss, three shutdown strategies were compared. Under the worst-case condition, peak fuel, emitter, and stainless steel cladding temperatures reach 2 500, 2 150, and 1 600 K, all remaining below design limits. In all cases, the reactor is safely shut down before thermal limits are exceeded, verifying the model’s ability to capture nonlinear feedback and shutdown margin. Overall, this work establishes a validated and physically consistent simulation methodology for thermionic space nuclear systems. The framework supports further safety evaluation, mission planning, and digital model development for future deep-space reactor applications operating under extreme environmental conditions.
This study conducted a simulation of iodine thyroid blocking in the Korean population, which typically has a high dietary iodine intake, using the Korean biokinetic model. We evaluated the thyroid protective effects of stable iodine administration and produced thyroid retention functions and dose coefficients for Koreans. Our findings highlight notable differences between the Korean model and the International Commission on Radiological Protection (ICRP) reference model. The faster recovery from the thyroid blocking, due to higher blood iodide concentrations, resulted in lower protective effects (66 % versus 86 % for 100 mg of stable iodine administered 24 h before iodine exposure) compared to the ICRP model. Additionally, the Korean model demonstrated higher thyroid retention functions, particularly when stable iodine was administered within 24 h before or 2 h after exposure, with delayed secondary peaks. Thyroid dose coefficients were also higher in the Korean model, with values up to 1.5 times greater, due to both lower protective effects and higher S values in Korean anatomical models. While this study offers valuable insights into the thyroid blocking effect in Koreans, this study does not undermine the validity of thyroid protection guidelines in Korea, which should be based on broader assessments, including pathological and risk-benefit analyses.
Enas Ismail Majeed, Laith Ahmed Najam, Mahmood Ahmed Hamood
et al.
The importance of radiation shielding is increasing due to the expanding areas exposed to radiation emissions. As a result, there is a crucial need to develop metal alloys and composites that demonstrate exceptional capabilities in absorbing neutron and gamma rays for effective radiation protection. The major purpose of this study is to determine the gamma photon attenuation coefficients of several Al–Cu–PbO alloys for radiation detection applications. The transmission geometry technique was used to calculate experimental mass attenuation coefficients at photon energies ranging from 0.662 to 1.33 MeV. To corroborate the experimental results, the mass attenuation coefficients for the alloys under consideration were calculated and confirmed by simulation using the MCNP5 method. The study analyzes the possibility of these alloys as alternative materials for nuclear radiation shielding applications.
Mitrajyoti Ghosh, Yuval Grossman, Chinhsan Sieng
et al.
We derive a complete expression for the neutrino-mediated quantum force beyond the four-Fermi approximation within the Standard Model. Using this new result, we study the effect of atomic parity violation caused by neutrinos. We find that the neutrino effect is sizable compared to the current experimental sensitivity and can also significantly affect the value of the Weinberg angle measured in atomic systems. This offers a promising method for detecting the neutrino force in the future and facilitates the application of precision atomic physics as a probe for neutrino physics and the electroweak sector of the Standard Model.
Tim Wittenborg, Ildar Baimuratov, Ludvig Knöös Franzén
et al.
The aerospace industry operates at the frontier of technological innovation while maintaining high standards regarding safety and reliability. In this environment, with an enormous potential for re-use and adaptation of existing solutions and methods, Knowledge-Based Engineering (KBE) has been applied for decades. The objective of this study is to identify and examine state-of-the-art knowledge management practices in the field of aerospace engineering. Our contributions include: 1) A SWARM-SLR of over 1,000 articles with qualitative analysis of 164 selected articles, supported by two aerospace engineering domain expert surveys. 2) A knowledge graph of over 700 knowledge-based aerospace engineering processes, software, and data, formalized in the interoperable Web Ontology Language (OWL) and mapped to Wikidata entries where possible. The knowledge graph is represented on the Open Research Knowledge Graph (ORKG), and an aerospace Wikibase, for reuse and continuation of structuring aerospace engineering knowledge exchange. 3) Our resulting intermediate and final artifacts of the knowledge synthesis, available as a Zenodo dataset. This review sets a precedent for structured, semantic-based approaches to managing aerospace engineering knowledge. By advancing these principles, research, and industry can achieve more efficient design processes, enhanced collaboration, and a stronger commitment to sustainable aviation.
Vladimir A. Solntsev, Dmitry M. Soldatkin, Vladimir N. Nuzhin
This paper describes the development of a dispersion-type uranium-zirconium fuel rod. Uranium is distributed in the zirconium matrix material in the form of axis-oriented fibers. The fuel rod is designed for the conversion of the IVG.1M research reactor (Republic of Kazakhstan) from highly enriched uranium (HEU) to low enriched uranium (LEU). The need for the HEU-LEU conversion arose in connection with Kazakhstan joining the program to convert research and test reactors to fuel with reduced enrichment (RERTR 2023). The study solves the problem of deformation of a low-tech U-Zr alloy (located in a zone of low plasticity) by replacing them with a heterogeneous compound. The manufacture of fuel rod is based on metal forming processes. Initially, a fuel rod wire with a core of fiber structure is formed by triple co-extrusion of cylindrical uranium and coaxial zirconium billets. At the next stage, the wire is processed to the required diameter by drawing, then the operation of flattening, twisting and cutting into specified lengths is carried out. Upon reaching a high total degree of deformation obtained during cold work, relaxation annealing is carried out at temperatures of 550 to 600 °C, which leads to the formation of a transboundary layer of the UZr2 intermetallic compound with a thickness of 1 to 2 μm. The intermetallic layer, without having a significant effect on the strength and thermal conductivity of the compound, ensures high quality diffusion bonding of all fuel rod components. The final operations are melting of the ends of the fuel rods and sealing by electroplating with nickel. As a result, blade-profile fuel elements are obtained with a thickness of 1.5 mm, a diameter of the circumcircle of 2.8 mm and an average effective diameter of uranium fiber of 40 μm. A set of 14040 fuel rods was manufactured and loaded into an operating IVG.1M reactor. The power start-up took place in 2023. Due to the unification and wide variability in the loading of the fuel component, in size and shape of the cross section, in structure and materials of the matrix compound, the fiber fuel element design can be used in the development of fuel rods for advanced reactors for various applications.
Monireh Hajizadeh, Mahdieh Sadeghian Sarayan, Akram Taleghani
et al.
Nanoscience is a prominent scientific field with great potential and many novel and cost-effective applications. Numerous green and environmentally friendly synthesis methods have been introduced that use different plant extracts to produce silver, gold, copper, and iron antibacterial nanoparticles. Plant extracts contain rejuvenating compounds which, when exposed to metal salts (in this research, silver nitrate), facilitate their reduction to metal ions. In the present investigation, Lepidium draba was used as a regenerating factor. Silver nanoparticles (AgNPs) containing Azmak leaf extract were synthesized under optimal conditions including silver nitrate concentration, time, temperature, and pH. These nanoparticles were then evaluated for their characteristics using transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), and zeta potential analyses. Subsequently, the antibacterial properties of nanoparticles were assessed using the broth microdilution method. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) method was also employed to examine the antioxidant properties of synthesized nanoparticles. Structural analyses revealed the formation of spherical, stable, and pure AgNPs with a size of 20–35 nm. The synthesized AgNPs exhibited strong antibacterial activity against Gram-negative and Gram-positive bacteria. In addition, investigation of the antioxidant activity of the nanoparticles showed 89% inhibition at a concentration of 250 μg/mL. AgNPs synthesized using the Azmak leaf extract can be employed as low-cost and efficient nanoparticles for environmental and biomedical applications and their dual antimicrobial and antioxidant characteristics could potentially position them as candidates for treating infectious wound.
Medical physics. Medical radiology. Nuclear medicine, Nuclear engineering. Atomic power
Objective: With the aging of the population, diabetes mellitus, peripheral vascular diseases, and the increased dialysis age of hemodialysis patients, the depletion of upper limb blood vessels and superior vena cava resources is becoming more visible. Methods: The lower limb arteriovenous diameter is relatively large, and the first patency rate after artificial arterioplasty is high, with fewer thrombotic events. Results: As a result, arteriovenous grafts (AVG) are an important supplement to the hemodialysis pathway after the upper limb hemodialysis pathway has been depleted. The presence of iliac vein stenosis/occlusion following AVG of the lower limbs is uncommon and rarely reported in the literature. Conclusions: Recently, two cases of iliac vein occlusion and treated with Viabahn film mulching stent have achieved good clinical results, which are reported as follows.
Medical physics. Medical radiology. Nuclear medicine, Nuclear engineering. Atomic power
Radioactive waste should be solidified before being disposed of in the repository to eliminate liquidity or dispersibility. Cement is a widely used solidifying media for radioactive waste, and cement solidified waste should satisfy the minimum compressive strength of the waste acceptance criteria of a radioactive repository. Although the compressive strength of waste should be measured by the test method provided by the waste acceptance criteria, the method differs depending on the operating repository of different countries. Considering the measured compressive strength changes depending on test conditions, the effect of test conditions should be analyzed to avoid overestimation or underestimation of the compressive strength during disposal. We selected test conditions such as the height-to-diameter ratio, loading rate, and porosity as the main factors affecting the compressive strength of cement solidified radioactive waste. Owing to the large variance in measured compressive strength, the effects of the test conditions were analyzed via statistical analyses using parametric and nonparametric methods. The results showed that the test condition of the lower loading rate, with a height-to-diameter ratio of two, reflected the actual cement content well, while the porosity showed no correlation. The compressive strength assessment method that reflects the large variance of strengths was suggested.
In this study, the rapidity distribution, collective flows, and nuclear stopping power in $^{197}\mathrm{Au}+^{197}\mathrm{Au}$ collisions at intermediate energies were investigated using the ultrarelativistic quantum molecular dynamics (UrQMD) model with GEMINI++ code. The UrQMD model was adopted to simulate the dynamic evolution of heavy-ion collisions, whereas the GEMINI++ code was used to simulate the decay of primary fragments produced by UrQMD. The calculated results were compared with the INDRA and FOPI experimental data. It was found that the rapidity distribution, collective flows, and nuclear stopping power were affected to a certain extent by the decay of primary fragments, especially at lower beam energies. Furthermore, the experimental data of the collective flows and nuclear stopping power at the investigated beam energies were better reproduced when the sequential decay effect was included.
Simone Salvatore Li Muli, Bijaya Acharya, Oscar Javier Hernandez
et al.
The extraction of nuclear charge radii from spectroscopy experiments in muonic atoms is currently limited by the large uncertainties associated with the theoretical evaluation of the nuclear polarizability effects. To facilitate calculations, these polarizability corrections are conventionally expressed as an expansion in a dimensionless parameter $η$, which has been argued in previous literature to hold an approximate value of 0.33 in light-nuclear systems. In this work, we check this claim by doing a Bayesian analysis of the nuclear-polarizability corrections to the Lamb shift in $μ^2$H and $μ^3$H atoms and in $μ^3$He$^+$ and $μ^4$He$^+$ ions at various orders in the $η$-expansion. Our analysis supports the claim that $η\ll 1$ in these systems and finds truncation uncertainties that are similar to the previous estimate, the only exception being the truncation uncertainties in the $μ^3$He$^+$ ion, which are found to be larger.
Igor A. Valuev, Gianluca Colò, Xavier Roca-Maza
et al.
A long-standing problem of fine-structure anomalies in muonic atoms is revisited by considering the $Δ2p$ splitting in muonic $^{90}\mathrm{Zr}$, $^{120}\mathrm{Sn}$ and $^{208}\mathrm{Pb}$ and the $Δ3p$ splitting in muonic $^{208}\mathrm{Pb}$. State-of-the-art techniques from both nuclear and atomic physics are brought together in order to perform the most comprehensive to date calculations of nuclear-polarization energy shifts. Barring the more subtle case of muonic $^{208}\mathrm{Pb}$, the results suggest that the dominant calculation uncertainty is much smaller than the persisting discrepancies between theory and experiment. We conclude that the resolution to the anomalies is likely to be rooted in refined QED corrections or even some other previously unaccounted-for contributions.
Liam Abrahamsen-Mills, Alan Wareing, Linda Fowler
et al.
An integrated waste management approach for irradiated graphite was developed during the European Commission project ‘Treatment and Disposal of Irradiated Graphite and other Carbonaceous Waste’. This included the identification of potential options for the management of irradiated graphite, taking account of storage, retrieval, treatment and disposal methods. This paper describes how these options can be assessed using multi-criteria decision analysis (MCDA) for a case study relating to a generic power reactor. Criteria have been defined to account for safety, environmental, economic and socio-political factors, including radiological impact, resource usage, economic costs and risks. The impact of each option against each criterion has been assessed using data from the project and the wider literature. A linear additive approach has been used to convert the calculated impacts to scores. To account for the relative importance of the criteria, example weightings were allocated. This application has shown that MCDA approaches can be used to support complex decisions regarding irradiated graphite management, accounting for a wide range of criteria. Use of this approach by individual countries or organisations will need to account for the specific options, scores, weightings and constraints that apply, based on their national strategies, regulatory requirements and public acceptability.
Over the past three years we have built a practice-oriented, bachelor level, educational programme for software engineers to specialize as AI engineers. The experience with this programme and the practical assignments our students execute in industry has given us valuable insights on the profession of AI engineer. In this paper we discuss our programme and the lessons learned for industry and research.