Coupled multi-physics analysis of low-enriched uranium nuclear thermal propulsion reactors

Macromolecular chains from curling to stretching: Charge-mediated conformational control in sulfonated membranes for high-performance uranium enrichment

Enhanced nuclear enrichment of chemotherapeutics by a biomimetic ZIF-8 nanosystem for multidrug-resistant cancer treatment.

Accurate prediction of total organic carbon (TOC) contentin ultradeepsource rocks exceeding 8,000 m burial depth represents a criticalchallenge in petroleum geoscience, where traditional methods demonstratesevere limitations due to extreme data scarcity and complex nonlinearrelationships between logging responses and organic matter distribution.This study introduces a physics-informed neural network (PINN) frameworkthat enables robust TOC prediction from minimal calibration data byintegrating fundamental petrophysical constraints directly into theneural network optimization process. The proposed PINN architectureincorporates three critical petrophysical constraints as explicitloss terms: the inverse relationship between formation density andorganic content, reflecting kerogen’s distinctive low-densityproperties; the positive correlation between gamma ray response andTOC due to uranium enrichment in organic-rich intervals; and empiricalconsistency validation through modified rock physics relationshipscalibrated for ultradeep conditions. This physics-informed approachensures predictions honor fundamental geological principles whilelearning from sparse data, effectively bridging the gap between data-drivenflexibility and physics-based reliability. Application to the LowerCambrian Yuertus Formation in the Tarim Basin’s L3 well validatesthe framework’s effectiveness under extreme conditions. Withlimited core-calibrated TOC measurements from depths exceeding 8,500m, the PINN model integrates multiple wireline logs including naturalgamma ray, deep resistivity, bulk density, and acoustic transit timeto generate continuous high-resolution TOC profiles. Quantitativeevaluation demonstrates that PINN achieves R2 of 0.9451 and an RMSE of 0.8571, representing R2 improvements of 282%, 18%, 14%, 13%, and 11% comparedto the ΔlogR method, multiple regression analysis (MRA), multilayerperceptron (MLP), random forest (RF), and support vector machine (SVM)models, respectively. Critically, the PINN model achieves both RMSEand MAE values below unity, ensuring geological consistency acrossdepth intervals where purely data-driven models produce unstable predictions.Qualitatively, the PINN predictions remain geologically consistentacross all depth intervals, avoiding the instabilities observed inpurely data-driven models and reliably capturing the nonlinear relationshipsbetween petrophysical logs and TOC content. This breakthrough establishesphysics-informed learning as an effective paradigm for petrophysicalcharacterization in data-scarce ultradeep environments, directly addressingthe petroleum industry’s critical need for reliable formationevaluation where conventional approaches fail.

BackgroundGlioblastoma (GBM) is the most aggressive and prevalent malignant brain tumor in adults, with poor prognosis despite current therapies. Cyclin-dependent kinase 1 (CDK1), a master regulator of cell cycle progression, has been implicated in oncogenesis, but its downstream phosphorylation network in GBM remains incompletely defined.MethodsCDK1 expression was examined in clinical GBM tissues and cell lines. Functional studies were performed in U251 cells using CDK1-specific shRNAs. Label-free phosphoproteomic profiling and bioinformatics analyses were conducted to map CDK1-regulated signaling pathways and substrates. Prognostic associations were evaluated using Clinical Proteomic Tumor Analysis Consortium (CPTAC) datasets, and functional assays were used to validate candidate substrates.ResultsCDK1 was significantly upregulated in GBM tissues, and its knockdown suppressed proliferation, migration, and invasion of U251 cells. Phosphoproteomic analysis identified 15,156 phosphorylation sites, of which 2,836 were significantly altered by CDK1 inhibition, implicating pathways related to cell cycle regulation, DNA replication, and DNA damage repair. Subcellular localization revealed nuclear enrichment, including phosphorylation changes in RB1 and TP53. Importantly, CDK1-mediated hyperphosphorylation of microtubule-associated protein 1B (MAP1B) at multiple residues (Ser832, Ser1260, Ser1899, Ser1939, Ser2209, Ser2271) correlated with poor prognosis and promoted microtubule destabilization. Functional assays confirmed that MAP1B knockdown impaired GBM cell growth, migration, and invasion.ConclusionThis study demonstrates that CDK1 is a critical oncogenic driver in GBM, regulating broad phosphosignaling networks and promoting tumor progression via MAP1B-dependent microtubule destabilization. MAP1B phosphorylation emerges as a potential prognostic biomarker. These findings support the development of CDK1-targeted therapies, alone or combined with microtubule-stabilizing agents, for improved GBM management.

Many advanced reactor designs require fuel enriched between 5% and 20% 235U. To assist in producing fuel at these enrichment levels, government-owned inventories of highly enriched uranium can be downblended. However, fuel produced from these inventories contain uranium impurities that are not often found when enriching natural uranium or accounted for when modeling reactor cores. To address this concern, this work models reactor designs like the X-energy Xe-100 and the Ultra Safe Nuclear Company’s Micro Modular Reactor, and compares their performance with fuel from enriching natural uranium to fuel from downblended highly enriched uranium. This paper evaluates the models based on the effective neutron multiplication factor, keff, effective delayed neutron fraction, βeff, and energy- and spatially dependent neutron flux, ϕ, as well as the fuel, coolant, moderator, and total reactivity temperature feedback coefficients, αF, αC, αM, and αT. The results show that the fuel from downblended highly enriched uranium inventories leads to differences in each of the metrics, especially in the keff values. In the Xe-100–like and Micro Modular Reactor–like models, keff changes by about 1400 pcm and up to 1200 pcm, respectively. Total reactivity feedback coefficients αT are negative with the impure fuels and the keff values remain above 1 for each core configuration and fuel composition. These results highlight that the impure fuel compositions do not necessarily prevent achieving key design parameters, such as cycle length, or from operating in a safe condition.

ABSTRACT From the perspective of integrating the 3S (safety, security, and safeguards), especially in developing innovative advanced nuclear power systems using HALEU (High Assay Low Enrichment Uranium), it is crucial to ensure that all 3S requirements are thoroughly met during the operational phase. However, monitoring systems currently in use are generally designed to monitor individual components of the 3S, and no comprehensive system that addresses all three components together has been developed yet. Therefore, this study proposes a new method for nuclear material monitoring systems that can simultaneously evaluate the target’s criticality (safety) and the amount of nuclear material (security and safeguards). To demonstrate the effectiveness of the newly developed method, experiments were conducted at Kyoto University Critical Assembly (KUCA) with HALEU samples and a DD neutron source. As a result, the simultaneous use of criticality monitoring and nuclear material accountancy achieved through the newly developed method was confirmed, and its capability to detect the absence of nuclear materials was also demonstrated. Therefore, the effectiveness of the new method was confirmed.

Rapid isotopic analysis of uranium microparticles via SP-ICP-TOF-MS.

The enrichment of chemotoxic uranium in the environment due to the rapid expansion of the nuclear industry to fulfil the growing energy demand has led to serious risks to human...

ABSTRACTExogenous melatonin has emerged as a pivotal multifunctional signaling molecule, recognized for its critical role in enhancing stress tolerance and improving crop productivity. N6‐methyladenosine (m6A) is the most prevalent internal modification found in eukaryotic mRNA and plays a crucial role in regulating plant growth, development, and stress responses. Despite its importance, the regulatory mechanisms of the m6A pathway in rice exposed to exogenous melatonin remain inadequately investigated. This study investigates systematic analysis of m6A‐regulatory gene families in rice. We identified a total of 124 genes, which include 7 writers, 22 readers, and 95 erasers. The distribution of these genes is uneven across the 11 chromosomes of the rice genome. Analysis of conserved domains revealed structural signatures that are specific to each gene family. Phylogenetic relationships with dicot and monocot species offered insights into evolutionary trajectories. Notably, gene structure and motif analyses revealed functional divergence within and between gene families. Cis‐element analysis identified abundance motifs associated with stress adaptation, hormonal signaling, and TFs, including ABRE, DRE, and MYB. Furthermore, synteny analysis unveiled both conserved regions and lineage‐specific expansions, particularly within the YTH and ALKBH families. The protein interaction network revealed robust connections among subgroups and identified 10 hub genes. GO and KEGG analyses indicated significant enrichment in stress‐related pathways, including secondary metabolite biosynthesis, flavonoid biosynthesis, and cysteine and methionine metabolism. RT‐qPCR validates that melatonin Osm6As significantly influences the expression of targeted genes, with melatonin upregulations exhibiting a time‐dependent pattern. Furthermore, GFP tagging of OsECT2 revealed that protoplasts are evenly distributed, suggesting robust nuclear enrichment of fluorescence. This study offers new insights into the epitranscriptomic regulatory responses of the m6A‐modifier.

Recent reports from the International Atomic Energy Agency (IAEA) highlight the alignment of the agency’s interests with Brazil’s atomic energy program, emphasizing its professionalism, transparency, and receptiveness. However, IAEA inspections have not always been free from political tensions in Latin America, incidents reviewed here. If there was a historic transition in international governance and Brazilian sovereignty based on uranium enrichment, when and how did it occur? Documentary analyses allow us to infer that the period 2003-2004 was crucial for guaranteeing Brazil’s industrial property rights and normalizing diplomatic, defense and energy relations with the IAEA and the USA.

The Wadi Khashab area in the southern Nubian Shield of Egypt records the transition from subduction-related to post-collisional magmatism, representing a major phase in the evolution of the Arabian-Nubian Shield. Understanding the geochemistry of uranium (U) and thorium (Th) is crucial for tracking magmatic and post-magmatic processes, as these radioactive elements provide valuable insights into crustal evolution. This study integrates field observations, petrography, whole-rock geochemistry, and gamma-ray spectrometric analyses of U and Th to clarify the petrogenesis and geodynamic setting of the granitic rocks. Two distinct magmatic pulses were identified: an older calc-alkaline suite (quartz diorite, tonalite, granodiorite) with low high-field-strength elements (HFSE: Nb = 8-20 ppm, Zr ∼200 ppm) and I-type characteristics, formed in a volcanic arc; and a younger suite of A-type biotite granites and altered varieties (albitized and greisenized), characterized by high SiO 2 and enrichment in incompatible elements. Geochemical modeling suggests that the older suite originated from the hybridization of mantle-derived melts with mafic lower crust, while the younger suite was derived from partial melting of the crust. U-Th geochemistry indicates that magmatic fractionation was overprinted by hydrothermal fluids, leading to significant uranium enrichment in the altered granites, with average contents of 16.2 ppm in albitized and 13.6 ppm in greisenized varieties. These altered granites are classified as uraniferous, with U and Th mainly hosted in resistant accessory minerals. This study links U-Th mobility to specific post-emplacement alteration events, providing new insights into post-accretionary fluid-driven processes in the Nubian Shield and highlighting the area's potential for uranium mineralization.

Deimos was the first critical experiment using high-assay low-enriched uranium (HALEU) TRistructural ISOtropic (TRISO) fuel in over 40 years. HALEU TRISO is the desired fuel form for many of the advanced reactor designs in development; however, very little experimental data are available for this fuel type. Deimos was designed to utilize existing HALEU TRISO fuel in a large graphite moderator to obtain nuclear and reactor physics data to fill the gaps surrounding this fuel type and enrichment. In addition to cold critical data, three separate heated experiments were conducted to measure the temperature reactivity coefficient for this type of system. These measured coefficients were then compared to simulated coefficients to a first level order of fidelity. This comparison showed very good agreement for the experiment where only the inner core was heated and good agreement for the other two configurations, which included heating portions of the outer core. Less agreement when the outer core was heated is attributed to potential heating in the beryllium reflector, which has a positive temperature reactivity coefficient and was unaccounted for in the first-order models. Future heated experiments with Deimos will include temperature monitoring of the beryllium reflector to account for beryllium heating in the simulations.

The article scrutinises the evolution of the AUKUS trilateral format announced by the leaders of Australia, United Kingdom and United States on September 15th, 2021, within the framework of a conceptual dichotomic model “continuity vs. discontinuity”. A review of Russian and international literature makes it possible to single out the major approaches to defining the gist of the agreement and interpreting its content, including from the standpoints of various international relations theories. The methodology of the study is represented by comparative analysis utilised diachronically while adhering to historicism as a principle. Apart from that, the application of discourse analysis reveals the particularities of the relevant terminology (e.g. the transition of the “pillar” metaphor as applied to AUKUS from the scholarly discourse into the official one), as well as the factors both favouring and impeding the implementation of the format. Addressing the intricacies of the Cold War period makes it possible to identify several levels of continuity. In the long-term, the continued cooperation within the blocs is notable, beginning with the 1947 UKUSA Agreement followed by the 1951 ANZUS pact. More recently, in the short-term perspective, there is AUKUS’ succession and complementarity with other minilateral initiatives in the Asia-Pacific (notably the informal quadrilateral security dialogue of the USA, Australia, India, and Japan – “Quad”). In the spatial dimension, the continuity manifests itself in the involvement of Canberra’s traditional allies in Europe and America (UK and US), similar to ANZUC. At the same time, the paper identifies the parameters determining the relative novelty of the agreement compared to the previous minilaterals in the Asia-Pacific. The most important of these is the nuclear component, creating a precedent of transferring nuclear propulsion technology involving highly enriched uranium (HEU) to a non-nuclear-weapon state (NNWS).

Uranium isotopic composition of shallow groundwater in the Jabal Sayid-Mahd Adhab area of western Saudi Arabia was investigated to evaluate geochemical changes resulting from water-rock interactions. The wide range of uranium concentrations (0.75–29.3 ppb) and 234U/238U activity ratios (1.11–3.11) reflect variable redox and uranium dissolution conditions across the aquifer. Samples with high uranium concentrations but low activity ratios suggest a recent release of uranium from mineral phases, which is further enhanced by the presence of fluoride ions. Fluoride’s strong reactivity aids in uranium dissolution by forming stable uranyl-fluoride complexes under open-system leaching conditions. Conversely, higher isotopic ratios in low-uranium samples suggest longer water-rock interaction and preferential leaching of 234U by alpha-recoil processes. The positive correlation between uranium and salinity parameters further indicates that uranium enrichment is linked to increased ionic strength and the abundance of complex ligands. The relationship between activity ratio 234U/238U (AR) and 1/U in the studied samples indicates that uranium behavior in the shallow aquifer is dominated by open-system leaching, with local binary mixing superimposed in a few sites. The findings emphasize that uranium isotopic composition is a valuable tool for identifying localized groundwater mixing and assessing the hydrogeochemical impacts of nearby mineralized areas on the aquifer system. These results represent an essential baseline for future environmental monitoring and for evaluating potential temporal changes in uranium behavior.

This study presents the first comprehensive assessment of heavy metal contamination, ecological risk, and potential human health implications in alluvial sediments from the Mbam and Noun Rivers in Central Cameroon. Eighty-two sediment samples were collected and analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) to determine the concentrations of Cr, V, Ni, Cu, Zn, Pb, Sn, U, and Th. The results were compared with upper continental crust (UCC) background values and ecotoxicological benchmarks, including threshold effect level (TEL), probable effect level (PEL), effect range-low (ERL), and effect range-median (ERM). Several contamination and ecological indices are as follows: contamination factor (CF), enrichment factor (EF), geo-accumulation index (Igeo), pollution load index (PLI), and ecological risk indices (Er, RI) were used to evaluate pollution intensity and its environmental implications. In the Mbam River, metal concentrations generally decreased upstream, following the order V > Cr > Zn > Ni > Cu > Pb > Th > Sn > U, with moderate contamination (CF = 1.2-3.5) and PLI values between 1.3 and 1.5, indicating diffuse anthropogenic influence. In contrast, the Noun River displayed extremely high uranium and vanadium enrichment (CF₍U₎ > 5; EF₍U₎≈3.8), resulting in RI values up to 240, which denote considerable to very high ecological risk. Human health indices revealed hazard index (HI) values below 1 for all sites, indicating no immediate non-carcinogenic risk, though children showed higher exposure (HI_child = 0.19-0.34) than adults. Total carcinogenic risk (TCR) values (10-⁶-10-4) remained within the acceptable range but were highest at downstream Mbam sites, reflecting cumulative exposure to Cr (VI), Ni, and U. These findings indicate that metal enrichment in both rivers stems from the weathering of uranium-bearing lithologies combined with localized anthropogenic activities, including artisanal mining and agricultural runoff. Continuous monitoring and integrated watershed management are recommended to mitigate ecological degradation and long-term health risks in the Mbam-Noun River system.

Nuclear myosin VI cooperates with actin to promote transcriptional cluster formation at androgen receptors

A mini-reactor design concept is desirable for deployment as a localized nuclear power station in support of carbon-free power supply for remote or dedicated applications. Aspects of high-burnup fuel coupled with an increased 235U enrichment loading are evaluated for once-through operation cycle performance. The mini-reactor design features versus conventional pressurized water reactor (PWR) core performance were investigated via verification-by-comparison. burnup calculations were performed using MCOS, coupling the Monte Carlo N-Particle® and ORIGEN codes, to an achievable high burnup of ~60 GWd/tonnes in approaching a keff of unity. At the end of core lifetime, the entire fuel core can be replaced with a new prefabricated fuel module. The results demonstrated that a conventional PWR fuel assembly using low-enriched uranium plus (LEU+) fuel (7.5 wt% 235U/U UO2) provides favorable performance with minimal impact on core burnup-dependent reactivity compared to a conventional PWR. The MINI-21 Doppler effect maintained negative feedback in the hot full-power condition at high burnups. In addition, the newly assessed reactor-grade uranium (RGU) with 4.95 wt% 235U/U UO2 can also achieve an acceptable burnup. The LEU+ and RGU high-burnup fission products and Doppler coefficient impacts on the MINI-21 design are bound by the PWR reference case.

Abstract As a critical fuel of nuclear energy, uranium peroxide precipitation and conversion represent critical steps in uranium extraction processes, directly determining the purity and recovery efficiency of the final product. However, the dynamic mechanism of uranium peroxide precipitation and conversion remains unclear. Here, we investigated the crystallization kinetics of metal peroxides, establishing empirical equations between crystallization rate and solution supersaturation under different metal concentration ranges. Combined the experimental observations with theoretical calculations, we showed that at the lower metal concentration the crystal growth dominates the crystallization process, while at the higher concentration range the nucleation becomes the dominant process. Further, mathematical models were developed to correlate crystallization rate with solution composition and operating parameters. Our findings provide fundamental insights to support the development of more efficient and scalable precipitation processes, addressing key challenges in the uranium purification and recovery.

A safety analysis has been conducted on the RSG-GAS reactor being utilized for 99Mo production from electroplated targets of low-enriched uranium (LEU) positioned in the reactor irradiation position. A static neutronic calculation was performed to investigate the reactivity changes and radial power peaking factor (PPF) while steady-state and transient thermal-hydraulic calculations were carried out to determine the maximum temperatures for the coolant, cladding, and fuel meat. The analysis employed the coupled neutron–thermal-hydraulic code MTRDYN. For optimal 99Mo production, calculations were conducted assuming all central irradiation position and irradiation position facilities were fully loaded with LEU targets. Based on the neutronic calculations, the reactivity changes and maximum radial PPF were found to be 1241.491 pcm and 1.354, respectively. The maximum fuel temperature was 133.35°C for steady-state conditions, while under loss-of-coolant flow, it peaked at 137.94°C. The reactivity-initiated accident transient analysis for positive reactivity insertion reported a maximum coolant temperature of 74.19°C for the 0.0342 $/s reactivity insertion rate, with a cladding temperature of 142.91°C, and a fuel meat maximum temperature of 143.93°C. Both the steady-state and transient calculations showed that the neutronic and thermal-hydraulic parameters were well below the RSG-GAS safety limits for reactor operation, showing the potential for RSG-GAS utilization for 99Mo production from the electroplated LEU target.