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Long time frames are to be considered in the safety and performance assessment of deep geological disposal of intermediate and high level radioactive waste. Geochemical conditions will change in the waste, conditioning matrix, waste package, engineered barriers and the host rock–all components present at the disposal cell scale. This aspect of geological disposal was the focus of the work package ACED (Assessment of chemical evolution of intermediate level (ILW) and high level (HLW) waste at disposal cell scale) in the EURAD project (the European Joint Programme on Radioactive Waste Management). The first part of this review provided a narrative of the geochemical evolution of the disposal cell. In this second part, an overview is given about methods and approaches that can be used to gain further insights into the processes driving the geochemical evolution, more in particular (i) laboratory and in-situ experiments, (ii) archaeological and natural analogues, and (iii) modelling tools. The review concludes with a short discussion on the consequences on material properties, waste forms and radionuclide mobility. [ABSTRACT FROM AUTHOR]

Nuclear power plants have the lowest life-cycle greenhouse gas emissions intensity and produce more electricity with less land use compared to any other low-carbon-emission-based energy source. There is growing global interest in Generation IV reactors and, at the same time, there is great interest in using small modular reactors. However, the development of new reactors introduces new engineering and chemical challenges critical to advancing nuclear energy safety, efficiency, and sustainability. For Generation III+ reactors, water chemistry control is essential to mitigate corrosion processes and manage radiolysis in the reactor's primary circuit. Generation IV reactors, such as molten salt reactors (MSRs), face the challenge of handling and processing chemically aggressive coolants. Small modular reactor (SMR) technologies will have to address several drawbacks before the technology can reach technology readiness level 9 (TRL9). Issues related to the management of irradiated graphite from high-temperature reactors (HTR) must be addressed. Additionally, spent fuel processing, along with the disposal and storage of radioactive waste, should be integral to the development of new reactors. This paper presents the key chemical and engineering aspects related to the development of next-generation nuclear reactors and SMRs along with the challenges associated with them. [ABSTRACT FROM AUTHOR]

AbstractThis study expands and enhances an activation assessment framework based on MCNP6.2® and FISPACT-II.4.0 to systematically evaluate the impact of steel equipment on neutron activation within a positron emission tomography cyclotron vault. The neutron flux submodel was experimentally validated at a cyclotron facility in operation, and the assessment framework was applied to a reference cyclotron in Korea to analyze how steel equipment characteristics affect neutron activation. The results showed that the presence of steel equipment reduces the activation of concrete walls by up to 50%. However, the steel itself may become significantly activated, surpassing the clearance level and potentially generating new low-level radioactive waste. This is primarily due to the cobalt impurity concentration in steel being up to 100 times higher than in concrete. Furthermore, the presence of steel equipment could increase the total radioactive waste volume by 120% to 1600% depending on the duration of decay storage.Based on these findings, it is recommended that steel equipment be located in a separate room outside the cyclotron vault to minimize activation and radioactive waste volume. For cases where the equipment must be housed within the vault, design provisions are proposed to reduce both equipment and concrete activation. These include (1) positioning steel equipment opposite the proton beam’s direction and as far as possible from the irradiated target and (2) considering cobalt-free nickel alloys to minimize activation. This study contributes valuable insights into optimizing cyclotron facility design and radioactive waste management to facilitate safe and efficient decommissioning. [ABSTRACT FROM AUTHOR]

To establish a deep disposal repository for high-level radioactive waste, it is crucial to develop a safety case, which is comprehensive evidence and arguments supporting the safety of a nuclear facility or activity. The development of safety cases is achieved by creating scenarios based on a comprehensive understanding of the disposal system. Scenarios are developed using Features, Events, and Processes (FEP) and must follow the rules of comprehensiveness, systematic approach, transparency, and traceability (rules for the scenario). Also, scenarios have to be developed in a way that the stakeholders understand the whole development process clearly. In this study, an intermediate step was introduced for the high-level radioactive waste management program to strengthen the rules for the scenario. An intermediate step was established through the integration of FEP. For integrating FEPs, we classified 268 NEA International FEPs into six classifications concerning the relationships between each FEP to scenario and safety objectives. Finally, we selected Repository system evolution FEPs as the target for integration because they can result in significant changes in system performance. [ABSTRACT FROM AUTHOR]

Radionuclides removal and immobilization are crucial issue for liquid radioactive waste management. Zr-Ca-Mg and Ti-Ca-Mg phosphates performance for Cs+ ions adsorption and immobilization was studied. Adsorption of stable Cs+ on composite phosphates was well described by Sips model and pseudo-second order kinetics. Zr-Ca-Mg samples had the highest Cs+ adsorption capacity (< 2.40 mmol/g) compared to Ti-Ca-Mg phosphates (< 2.18 mmol/g). The samples with high Ti and Zr content were characterized by enhanced efficiency of 137Cs radionuclide adsorption (Kd > 104 mL/g) in wide range pH of 4.0–10.0. Metal phosphates calcined at 1000 °C shown the safe immobilization of Cs+ ions. [ABSTRACT FROM AUTHOR]

Nuclear energy accounts for ≈10% of global energy production, positioning it as a promising solution for achieving carbon neutrality amid escalating concerns over climate change. Nonetheless, the effective management of radioactive waste, which can remain hazardous for up to one hundred thousand years, presents considerable challenges that must be addressed to uphold public trust and safeguard environmental safety. This review outlines the fundamental stages of nuclear decommissioning including strategic planning, decontamination, dismantling, remediation, encapsulation, deregulation, and site reuse as a critical component of sustainable environmental practices. The review also highlights the significance of efficient decontamination processes in reducing waste generation. Various decontamination techniques, including mechanical, electromechanical, chemical, and advanced methods such as laser and plasma decontamination, are evaluated for their effectiveness and limitations. Moreover, the review emphasizes the need to enhance the recovery and recycling of ion exchange resin and potential radionuclides during decontamination processes to minimize waste and to address the depletion of potential radionuclide resources. Future research should prioritize the development of innovative techniques for decontamination and radioactive waste management, fostering sustainable decommissioning and supporting the ongoing development of nuclear energy in an environmentally responsible manner. [ABSTRACT FROM AUTHOR]

Nuclear Transparency Watch (NTW) is a non-governmental organisation, based on French law from 1905, devoted to nuclear safety and transparency, organised as network of NGOs and experts in almost all European countries. Building on the Aarhus Convention, NTW works to ensure that civil society is present at the heart of expertise and decision-making on nuclear safety and security in the European Union. The network's activities cover the entire nuclear cycle, with a particular focus on operational safety, including issues such as life extension of old nuclear power plants, emergency preparedness and response (EP&R), post-accident management, radioactive waste management (RWM), decommissioning and environmental issues. In parallel, the topic of transparency is constantly followed, at the national or European level. Some more important activities included: organisation of thematic Aarhus Convention and Nuclear round tables on important topics like EP&R and RWM with European partners, follow-up of the implementation of the Radioactive Waste Directive (2011/70/EURATOM), participation in the research RWM programme EURAD (The European Joint Programme on Radioactive Waste Management) to access the expertise based on the double wing model utilised, assessment of the independence of nuclear regulators in the different national contexts of the EU, development of rolling stewardship in the context of long term RWM. NTW builds a strong institutional presence and visibility at the European and UN level [links with the European institutions, International Atomic Energy Agency (IAEA), the Convention for the Protection of the Marine Environment of the North-East Atlantic (the OSPAR Convention)] and coordinate its members in activities. The main results will be described and discussed. [ABSTRACT FROM AUTHOR]

The removal of radioactive Cs(I) is critical for the management of radioactive liquid waste. In this study, four sorbents impregnated with different 1,3-alternate calix[4]arane-2,4-crown-6 ligands on XAD-7 resin were prepared for Cs(I) selective removal from strongly acidic aqueous solution. The ligands differ in the substituent groups (benzyl, 4-tert-butyl benzyl, isopropyl, and n-octyl) at 1,3-alternate positions of the supramolecular platform of calix[4]arane-2,4-crown-6 ether. The sorption of Cs(I) was investigated as a function of contact time, HNO3 concentration, ligand concentration and temperature using a batch method. The experimental results indicated that Cs(I) sorption on the sorbents is rapid and reaches sorption steady state in 30 min. All sorbents exhibit excellent Cs(I) sorption selectivity in a simulated high-level liquid waste (HLLW). Cs(I) sorption on the sorbents is an exothermic process. The substituent groups of the ligands affect both the kinetics and the thermodynamics of Cs(I) sorption on the sorbents. The sorbents impregnated with benzyl and 4-tert-benzyl derivatives exhibit better Cs(I) sorption performance in terms of Cs(I) sorption distribution coefficient and Cs(I) selectivity in the simulated HLLW system. [ABSTRACT FROM AUTHOR]

In the search for a repository site for high-level radioactive waste in Germany, the perception of safety and trust in the actors are central to public acceptance. In communicating safety, methods of safety assessment and the role of uncertainties need to be addressed. Given the complexity of the issue, there is a need for indicators that are suitable both for assessing the long-term safety of repositories and for communicating with the general public. Similarly, there is a requirement to communicate uncertainties in an accessible manner. The TRANSENS project provides basic research in nuclear waste management (NWM) and utilizes a transdisciplinary approach: Non-experts who are not directly affected by the site selection process and who have no stated interest in NWM are involved in the research process, as are practice actors. A series of four transdisciplinary workshops was specifically designed to explore the perspectives of individuals with a high level of disciplinary knowledge but no system knowledge of NWM. Participants were selected from doctoral students in science and technology who had no prior knowledge in this area. Two of these workshops address the questions stated above and are presented here. The article describes the considerations underlying the workshop planning and implementation phases, and the content developed in the workshops on indicator selection and visualisation of uncertainties. The participants compiled a list of desirable indicator properties, which showed a high degree of congruence with the relevant literature. A proposal for a database to collect, administer and assess uncertainties shows similarities with the approach followed by the German implementer and complements it with an interactive visualisation. Transdisciplinary work is resource-intensive and its use in a research context must be carefully considered for each individual application. A transdisciplinary approach was successfully used for the purposes of method validation, method optimisation and the development of disciplinary impulses. An application of transdisciplinary approaches for optimising the Safety Case of nuclear repositories is feasible. [ABSTRACT FROM AUTHOR]

The Strategic Research Agenda (SRA; https://www.ejp-eurad.eu/publications/eurad-sra) of the European Joint Programme on Radioactive Waste Management (EURAD; https://www.ejp-eurad.eu/) describes the scientific and technical domains and sub-domains and knowledge management needs of common interest between EURAD participant organizations. Theme number 7 is entitled "Performance assessment, safety case development and safety analyses." A list of research and development priorities and activities of common interest to be addressed within EURAD for theme 7 have been established. Amongst others, the Understanding and modelling of multi-physical Thermo-Hydro-Mechanical-Chemical coupled processes (THMC) occurring in radioactive waste disposal is a major and permanent issue to support optimization of design and safety case abstraction. To tackle this challenge a research work package entitled "DONUT: Development and improvement of numerical methods and tools for modelling coupled processes" has been conducted within the EURAD join programming initiative. The purpose of this work package is to improve/develop methods or numerical tools in order to go a step further in development of (i) relevant, performant and cutting-edge numerical methods that can easily be implemented in existing or new tools, in order to carry out high-performance computing to facilitate the study of highly coupled processes in large systems, (ii) numerical scale transition schemes for coupled processes, (iii) innovative numerical methods to carry out uncertainty and sensitivity analyses. In this paper the work carried out within the DONUT work package is put in perspective regarding the existing concept and literature on the field. It does not pretend to be exhaustive but rather to put emphasis on particular issues tackled during the project. [ABSTRACT FROM AUTHOR]

Sealed radioactive sources within industrial nuclear gauges eventually decay and become disused. Disposing of these disused sealed radioactive sources (DSRS) is crucial to prevent potential harm to workers, the community, and the environment. According to the Code of PNRI Regulations (CPR), DSRS must be decommissioned when no longer in use, a task entrusted to authorized organizations with technical expertise. The Philippine Nuclear Research Institute (PNRI), operating the Radioactive Waste Management Facility, assumes this responsibility. Three nuclear gauges were decommissioned in compliance with CPR at a coal-fired power plant in Quezon, Philippines. These gauges were safely packaged in 200-L drums, registering a surface dose rate of 13.91 uSv/h - well below the 2.0 mSv/h regulatory limit for safe radioactive package transport. The effective dose received by the QPP and PNRI personnel was below the criteria for occupationally exposed workers. Lastly, the radiation dose and removable contamination measurements from the start and end of the activity were below the prescribed limits of the CPR. The conclusion of the activity resulted in the successful decommissioning of the nuclear gauges and their disposal, thereby reducing the risk of radiation exposure to the workers and the members of the public, as well as the environment. [ABSTRACT FROM AUTHOR]

In this study. Baghdad hospital waste ash was analyzed to determine the type of heavy and toxic concentrations in the waste and to study the potential effects of radioactive waste, health risks and the effectiveness of S/S hardening/stabilization processes based on local cement. Toxic medical waste was used in this work as bottom ash, which includes large amounts of pollutants such as As, Co, Cr, and Hg. Ash samples were taken from the medical waste incinerators of the main hospital in the city. The heavy metal sludge is stabilized and solidified using this bottom ash. The curing matrix was between 7% and 25% local cement in varying amounts. Before arriving at the physical and chemical properties of the solid, it underwent six different periods of treatment. Filtration experiments using solid-liquid partitioning as a function of pH, the filtration method was deployed to determine treatment efficiency. The compressive strength confined to the forms was also measured to ensure the solidity and durability of the molds. After disposal, the most effective solid material with good strength was found, which contains 25% of local cement. In addition, the results of the study showed that the efficiency of treating the filtration method for toxicological properties Ranging from 85% to 100%. The range of treatment efficiency in liquid/solid technology was 75%-100%. The S/S process can be a very good, effective and safe treatment process for handling and disposing of toxic medical waste ash or the possibility of reusing the formwork in bridges and roads. [ABSTRACT FROM AUTHOR]

This paper presents an optimized design approach using nonlinear dynamic analysis and finite element methods to ensure the structural integrity of square-shaped containers made from ductile cast iron for intermediate- and low-level radioactive waste packaging. Ductile cast iron, with its spherical graphite structure, effectively distributes stress throughout the material, leading to a storage capacity increase of approximately 18%. Considering the critical need for containers that maintain integrity under extreme conditions like earthquakes, the design focuses on mitigating stress concentrations at the corners of square structures. Nonlinear dynamic analyses were conducted in five drop directions: three specified by ASTM-D5276 standards and two additional directions to account for different load patterns. Fractures were observed in four out of the five scenarios. For each direction where fractures occurred, equivalent loads causing similar displacement fields were applied to linear static models, which were then used for multi-load topology optimization. Three optimized models were derived, each increasing the volume by 1.4% to 1.6% compared to the original model, and the design that best met the structural integrity requirements during drop scenarios was selected. To further enhance the optimization process, weights were assigned to different load conditions based on numerical analysis results, balancing the impact of maximum stress, average stress, and plastic deformation energy. The final model, with its increased storage capacity and enhanced structural integrity, offers a practical solution for radioactive waste management, overcoming limitations in previous designs by effectively addressing complex load conditions. [ABSTRACT FROM AUTHOR]

Radioactive waste management is a fundamental issue when using nuclear energy. Therefore, it is necessary to study the health and biological effects on human and environment that these radionuclides cause.  The aim of the present study is to estimate the radiotoxicity for radioactive waste in stocked soil in Al-Twaitha city.  The radiotoxicity was calculated for each radionuclide, present in the waste, using their dose factor due to ingestion, which is given by the International Commission on Radiological Protection (ICRP) compendium. For the purpose of calculating radiation toxicity, a scenario was built that 20% of the radioactivity during radioactive waste handling processes is in the form of dust that can be inhaled or entered through the mouth or eyes. Drums Characterization System (DCS) provided with portable HPGe hand-held radioisotope identifier was used for the characterization and identification of the radionuclides in the drums and the dose rate was measured by Ludlum radiation detector. The absorbed dose rate ranged from 134.904nGy h-1 to 788400 nGy.h-1, the internal hazard index  from 0 to 0.035, representative gamma index   from 0 to 0.068, representative alpha index (  from 0 to 0.017, excess lifetime cancer risk (ELCR) value ranged from 0.66× 10-6   to 3.86×10-3 and the range of AEDE from 0.19 mSv to 1103.76 mSv. [ABSTRACT FROM AUTHOR]

Monitoring a deep geological repository for radioactive waste during the operational phases relies on a combination of fit-for-purpose numerical simulations and online sensor measurements, both producing complementary massive data, which can then be compared to predict reliable and integrated information (e.g., in a digital twin) reflecting the actual physical evolution of the installation over the long term (i.e., a century), the ultimate objective being to assess that the repository components/processes are effectively following the expected trajectory towards the closure phase. Data prediction involves using historical data and statistical methods to forecast future outcomes, but it faces challenges such as data quality issues, the complexity of real-world data, and the difficulty in balancing model complexity. Feature selection, overfitting, and the interpretability of complex models further contribute to the complexity. Data reconciliation involves aligning model with in situ data, but a major challenge is to create models capturing all the complexity of the real world, encompassing dynamic variables, as well as the residual and complex near-field effects on measurements (e.g., sensors coupling). This difficulty can result in residual discrepancies between simulated and real data, highlighting the challenge of accurately estimating real-world intricacies within predictive models during the reconciliation process. The paper delves into these challenges for complex and instrumented systems (multi-scale, multi-physics, and multi-media), discussing practical applications of machine and deep learning methods in the case study of thermal loading monitoring of a high-level waste (HLW) cell demonstrator (called ALC1605) implemented at Andra's underground research laboratory. [ABSTRACT FROM AUTHOR]

The current scenario of radioactive waste management requires innovative and automated solutions to ensure its effectiveness and safety. In response to this need, the Proximity Imaging System for Sort and Segregate Operations (PI3SO) project was proposed. It is a gamma radiation proximity scanner system for radioactive waste with the primary goal of speeding up some aspects of the waste management cycle while reducing direct human operations. The system will provide proximity imaging for hot-spot finding and spectral analysis for radiological characterization, enabling semiautomatic recognition, sorting and separation of radioactive waste. The core of the proposed scanning system consists of an array of 128 CsI(Tl) scintillators, 1 cm3 size, coupled with silicon photomultipliers (SiPMs), installed on a motorized bridge sliding along a suitable table in order to scan the materials under investigation. [ABSTRACT FROM AUTHOR]

The joint action of human activities and environmental changes contributes to the frequent occurrence of landslide, causing major hazards. Using Interferometric Synthetic Aperture Radar (InSAR) technique enables the detailed detection of surface deformation, facilitating early landslide detection. The growing availability of SAR data and the development of artificial intelligence have spurred the integration of deep learning methods with InSAR for intelligent geological identification. However, existing studies using deep learning methods to detect landslides in InSAR deformation often rely on single InSAR data, which leads to the presence of other types of geological hazards in the identification results and limits the accuracy of landslide identification. Landslides are affected by many factors, especially topographic features. To enhance the accuracy of landslide identification, this study improves the existing geological hazard detection model and proposes a multi-source data fusion network termed MSFD-Net. MSFD-Net employs a pseudo-Siamese network without weight sharing, enabling the extraction of texture features from the wrapped deformation data and topographic features from topographic data, which are then fused in higher-level feature layers. We conducted comparative experiments on different networks and ablation experiments, and the results show that the proposed method achieved the best performance. We applied our method to the middle and upper reaches of the Yellow River in eastern Qinghai Province, China, and obtained deformation rates using Sentinel-1 SAR data from 2018 to 2020 in the region, ultimately identifying 254 landslides. Quantitative evaluations reveal that most detected landslides in the study area occurred at an elevation of 2500–3700 m with slope angles of 10–30°. The proposed landslide detection algorithm holds significant promise for quickly and accurately detecting wide-area landslides, facilitating timely preventive and control measures. [ABSTRACT FROM AUTHOR]

Over the last 15 years, there has been substantial growth in the installation of medical cyclotrons. This is mainly due to the increased demand for the production of positron emission tomography radiopharmaceuticals. In every country, there is a regulatory body that regulates the uses of medical cyclotron intending to protect occupational workers, the public, and the environment. It regulates the entire stages of such facilities, which mainly controls regulatory activities such as construction, commissioning, operation, and decommissioning. This article primarily highlights the key practices for planning and installation of a medical cyclotron facility (MCF). It also covers the particular aspects that should be considered in the early stages of project planning and provides information for best practices and challenges. If these aspects are properly addressed, then it ensures the safe operation of the MCF. The texts also elaborate on the necessary requirements for effective planning of the MCF, such as layout and space considerations, workload plan and maximum research capacity of the institute and equipment, shielding requirements, water cooling circuit, storage of radioactive components, management of radioactive waste from medical cyclotron and radiochemistry laboratory, construction and commissioning project management, exhaust system and filtration options, plans for staffing and training, and combination of equipment safety systems and building safety systems. [ABSTRACT FROM AUTHOR]

This article examines the legal framework governing nuclear radioactive waste management in South Korea, with a focus on regulations pertaining to ocean discharge. It analyzes key South Korean legislation, including the Nuclear Safety Act and Radioactive Waste Management Act, as well as relevant government agencies and disposal methods. The paper finds that South Korea generally prohibits ocean disposal of radioactive waste, with no exceptions for extenuating circumstances like natural disasters. However, regulations distinguish between radioactive waste and radioactive effluents, with the latter potentially allowed for discharge under certain conditions. The article concludes by recommending the establishment of international norms to address gaps in regulating ocean discharge of radioactive materials, especially in emergency situations. It suggests defining key terms, setting unified standards, maintaining prohibitions on radioactive waste disposal, and creating mechanisms for oversight and dispute resolution at the international level. [ABSTRACT FROM AUTHOR]

Globally, but especially in the Chinese Loess Plateau, landslides are considered to be one of the most severe and significant geological hazards. The purpose of this study is to design two ensemble machine learning methods, which are denoted as ADTree-Dagging and SVM-Dagging, for modeling landslide susceptibility in Lanzhou City (China). For this aim, the slope units extracted by the curvature watersheds method are used to construct landslide susceptibility modeling, and ten landslide conditioning factors are included in the landslide susceptibility evaluation (altitude, slope angle, slope aspect, cutting depth, surface roughness, relief amplitude, gully density, rainfall, distance to roads, and lithology). The conditioning factors selection and spatial correlation analysis were implemented by using the correlation attribute evaluation method and the frequency ratio model. The comprehensive performance of the models was tested using the receiver operating characteristic (ROC), area under the ROC curve (AUC), the root mean square error (RMSE), and several other performance metrics. For the training dataset, the results show that the SVM-Dagging model acquire the largest AUC value (0.953), lowest RMSE (0.3125), highest positive predictive value (96.0%), highest negative predictive value (91.2%), highest sensitivity (91.6%), highest specificity (95.8%), highest accuracy (93.6%), and highest Kappa (0.873). Similar results are observed in the validation dataset. Results demonstrated that the Dagging technique has improved significantly the prediction ability of SVM and ADTree models. The Dagging method can combine different models by leveraging the strengths of each model to create methods with higher flexibility than traditional machine learning methods. Therefore, in this study, the proposed new models can be applied for land-use planning and management of landslide susceptibility in the study area and in other areas containing similar geological conditions. [ABSTRACT FROM AUTHOR]

With the development of computer technology, landslide recognition based on machine learning methods has been widely applied in geological disaster management and research. However, in landslide identification, the problems of an insufficient number of samples and an imbalance of samples are often ignored; that is, landslide samples are much smaller than non-landslide samples. In order to solve this problem, taking the main urban area of Lanzhou City as an example, this paper proposes to construct a semi-supervised generated countermeasure network (SSGAN) model, which aims to achieve high performance with a limited number of labeled samples for precise landslide identification, and to help prevent and reduce the harm caused by disasters. In order to express the environmental characteristics of landslide development and the optical texture features of landslide occurrence, the study constructs three sets of samples to represent landslide features, including a landslide influencing factor sample set, a Sentinel-2A optical remote sensing sample set, a joint influencing factor and Sentinel-2A sample set. The three kinds of sample sets are transferred to SSGAN for training to form a comparative study. The results show that the joint sample set has excellent feature results in discriminator and generator. Through the experimental comparison, the model proposed in this paper is compared with the model without semi-supervised generated confrontation training. The experimental results show that the proposed method is better than the unsupervised adversarial learning model in terms of accuracy, F1 score, Kappa coefficient, and MIoU. A total of 160 landslides have been identified in the study area, with a total area of 10.328 km2, with an accuracy rate of 83%. Therefore, the generated results are accurate and reliable, and show that SSGAN can better distinguish landslides from non-landslides in an image, under the condition of obtaining a large number of unmarked environmental features; enhance the effect of landslide classification in complex geographical environment; and then put forward effective suggestions for the prevention and control of landslides and geological disasters in the main urban area of Lanzhou. [ABSTRACT FROM AUTHOR]

The upstream Jinsha River, located in the eastern Tibetan Plateau, has been experiencing intense geological hazards characterized by a high density of ancient landslides, significant deformation and reactivation challenges. In this study, remote sensing interpretation, field investigations, and Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technologies have been employed. Along a 17 km stretch of the Jinsha River, specifically in the Xiongba-Sela segment, 16 large-scale ancient landslides were identified, 9 of which are currently undergoing creeping deformation. Notably, the Sela and Xiongba ancient landslides exhibit significant deformation, with a maximum deformation rate of −192 mm/yr, indicating a high level of sliding activity. The volume of the Sela ancient landslide is estimated to be 1.8 × 108 to 4.5 × 108 m3, and characterized by extensive fissures and long-term creeping deformation. The SBAS-InSAR results revealed significant spatial variations in the deformation of the Sela ancient landslide, generally displaying two secondary zones of intense deformation, and landslide deformation exhibits nonlinear behavior with time. Between January 2016 and February 2022, Zone III1 on the southwest side of the Sela ancient landslide, experienced a maximum cumulative deformation of −857 mm, with a maximum deformation rate of −108 mm/yr. Zone III2, on the northeast side of the Sela ancient landslide, the maximum cumulative deformation was −456 mm, with a maximum deformation rate of −74 mm/yr; among these, the H2 and H4 secondary bodies on the south side of III1 are in the accelerative deformation stage and at the Warn warning level. We propose that the large-scale flood and debris flow disasters triggered by the Baige landslide-dammed lake-dam broken disaster chain in Tibetan Plateau during October and November 2018 caused severe erosion at the foot of downstream slopes. This far-field triggering effect accelerated the creep of the downstream ancient landslides. Consequently, the deformation rate of Zone III2 of the Sela ancient landslide increased by 6 to 8 times, exhibiting traction-type style reactivation. This heightened activity raises concerns about the potential for large-scale or overall reactivation of the landslide, posing a risk of damming the Jinsha River and initiating a dam-break disaster chain. Our research on the reactivation characteristics and mechanisms of large ancient landslides in high deep-cut valleys provides valuable guidance for geological hazard investigation and risk prevention. [ABSTRACT FROM AUTHOR]

The French National Radioactive Waste Management Agency is leading the design of a deep geological radioactive waste disposal to be located in the Callovo-Oxfordian formation. At the disposal main level, large-diameter galleries will ensure access to the storage cells and connection between zones. After a long operational period, the disposal will be closed by sealing structures located at some key positions to ensure post-closure safety over the long term. The seals are intended to prevent the flow of water and the migration of radionuclides from the disposal to the biosphere throughout the entire storage life. Thus, the long-term safety of the disposal relies to a large extent on the performance of these structures. The paper presents the work carried out to assess and simulate the phenomena underlying the response and performance of a large-diameter sealing concept under real disposal conditions. The complexity of the problem is addressed by considering in the simulations large-scale 3D geometries, advanced constitutive models, complex coupled phenomena, key geometric details at decimetre scale, and all the phases from the excavation to the post-closure period (~ a few thousand years). Highlights: The three-dimensional hydro-mechanical modelling of a large structure concept, foreseen to seal access galleries in a clayey rock deep disposal, has been carried out. Model considers large geometry (order of tens of meters), anisotropy, constitutive laws of different complexity, interfaces, and relevant geometrical details (order of cm). Results evidence a progressive hydration and swelling of the sealing core during more or less 2000 years after disposal closure. The concrete plugs placed at both ends of the sealing structure move longitudinally, but core density and swelling pressure do not change significantly in seal central part. Swelling core recompresses partially the excavation-induced damaged zone in the area of lining deposition. [ABSTRACT FROM AUTHOR]

Clay formations are one of the options currently being considered for the storage of radioactive wastes worldwide. In France, the National Radioactive Waste Management Agency (Andra) operates the Meuse/Haute-Marne Underground Research Laboratory in the Callovo-Oxfordian (COx) clay formation to assess the feasibility and safety of an industrial radioactive waste repository. A good level of understanding of the thermo-hydromechanical behaviour of the host rock is paramount for the safety assessment. A new anisotropic elastoplastic damage and viscoplastic model is proposed to describe the hydromechanical behaviour of the COx claystone based on a large dataset of experimental evidence. The model is based on the Hoek and Brown criterion and considers recent findings of the COx hydromechanical behaviour. The key mechanisms considered are: plastic strain hardening prior to reaching the peak strength, a post-peak behaviour characterised by strain softening in the frame of continuum damage mechanics and a residual stage represented by a perfectly plastic behaviour. Time-dependent deformations are also included based on a creep model, which in this work is coupled with damage. The proposed model was implemented with a regularisation scheme based on the non-local implicit gradient in Comsol Multiphysics® with the purpose of performing THM modelling (1D, 2D and 3D) in the framework of the Cigéo project. The numerical implementation is first validated based on several simulations of creep tests at different deviatoric stress and triaxial compression tests at different confining pressures and angles between the loading direction and the bedding, α. Then, the GCS drift hydromechanical behaviour is simulated considering transverse isotropic conditions. It is shown that the model is capable of reproducing the measured peak of pore pressure in sensors near the GCS wall as well as the drift convergence. Importantly, the predicted extent of damaged zones around the drift is consistent with the in situ observations. The impact of damage on the time-dependent behaviour and the permeability was investigated numerically. It was found that the magnitude and anisotropy of drift convergence and the pore pressure drop are sensitive to this coupling and the best agreement was obtained when this effect was taken into account. Finally, the performance of the regularisation scheme is demonstrated with a set of simulations of the drift with different mesh refinements. It is concluded that the proposed model captures the key features of the hydromechanical behaviour of the COx claystone. Highlights: An advanced constitutive model that takes into account the recent findings on the key mechanisms of deformation and failure of COx claystone is proposed. Strain hardening/softening, anisotropic elasticity and plasticity, damage described in the framework of CDM and time-dependent behaviour of COx claystone are considered. The effect of damage and shear fracturation on the transport and viscous properties are also addressed in the model. The model with a regularisation scheme is implemented in Comsol Multiphysics®, which allows several physics to be considered, then to perform 1D, 2D and 3D THMC modellings. The operational nature of the proposed model is successfully evidenced on the GCS drift of the MHM URL, for which the in situ observations are the most challenging to reproduce. [ABSTRACT FROM AUTHOR]

This study is part of numerical simulations performed on an in-situ heating test conducted by the French National Radioactive Waste Management Agency (Andra) at the Meuse/Haute-Marne Underground Research Laboratory (URL) to study the thermo-hydromechanical behavior of the host Callovo-Oxfordian COx claystone in quasi real conditions, through the international research project DECOVALEX. We present a numerical study of damage and cracking process in saturated claystone subjected to thermo-hydromechanical coupling by considering material heterogeneity distribution. For this purpose, a macroscopic elastic model is first determined by using two steps of homogenization by taking into account the effects of porosity and mineral inclusions. This model is implemented into a finite element code devoted to solving thermo-hydromechanical coupling problems. The nucleation and propagation of cracks are described by using an extended phase-field method, considering the effects of temperature and fluid pressure on the evolution of phase-field. The proposed model is applied to the numerical analysis of cracking process due to excavation and heating around a group of boreholes (CRQ). The numerical results of the 3D simulation are compared with in-situ measurements of temperature and pore pressure distribution. The excavation damage zone and heating fracture is reproduced and analysed according to the structure of the heating position and the heterogeneity of the rock. Highlights: A phase-field model is developed with thermo-hydromechanical processes; Both tensile and shear cracks are taken into account; Crack nucleation is emphasized by spatial heterogeneity of material properties; Cracking processes due to thermal-hydraulic interaction are analyzed in three-dimensional conditions. [ABSTRACT FROM AUTHOR]

A deep geological facility (Cigéo project) is planned, if authorized, in the Callovo-Oxfordian claystone (COx) for the disposal of all long-lived radioactive waste produced in France. The heat emitted from the most exothermic wastes, emplaced in horizontal parallel micro-tunnels, will lead to a temperature increment within the COx. The resulting thermal pressurization may lead to tensile effective stresses and induce thermal hydrofracturing. One of the design criteria for this area is to avoid any damage induced by thermal loading, especially in the far field. The French National Radioactive Waste Management Agency (Andra) has conducted an in situ heater experiment at the Meuse/Haute-Marne Underground Research Laboratory to better understand the thermal hydrofracturing process of the COx. The experiment's design was conceived in a way that the thermal pressurization will be sufficiently high to generate effective tensile stresses larger than the effective tensile strength of the COx. To induce thermal hydrofracturing, the COx was submitted to temperatures and pore pressures higher than those expected in the Cigéo project. A breakdown pore pressure, a sign of a fracture event, was registered by the measurements during the second heating cycle. These observations were also confirmed by the post-test core drilling. Furthermore, the numerical modelling of the experiment shows that the thermo-poro-elastic approach reproduces the temperature and pore pressure measurements well in a wide range of locations up to just before the occurrence of the fracture event. This satisfactory reproduction provides confidence for the design of the Cigéo project. Highlights: An in situ experiment was performed in the Meuse/Haute-Marne Underground Research Laboratory to study the thermal hydrofracturing of the Callovo-Oxfordian claystone. The heating strategy consisted of applying a thermal load to reach the tensile strength and to fracture the rock. The measurements, the numerical modelling, and the post-test core drilling indicate a fracture was created after two heating phases. The thermal pressurization induced a hydraulic fracture during the second phase after 28 days of heating. The thermo-poro-elastic approach reproduces well the measurements in a large range of the measurement locations. [ABSTRACT FROM AUTHOR]

Tourist volcanic caves are in high demand for ecotourism and geotourism lovers, as well as by sun and beach tourists as a complementary activity during their holidays. There are six tourist volcanic caves in the Canary Islands, all of them managed by the local administration of the island. The managers of these caves must ensure the safety of visitors and workers, who are exposed to natural hazards, such as radon, inherent to the environment in which the activity takes place. The methodology for analyzing natural radon radiation is based on the latest studies published by experts in this field and on previous experiences in tourist caves. This article proposes a protocol for the correct management of radon in tourist caves in the Canary Islands, adapted to current regulations, to mitigate effects on the health of visitors and workers. Plain Language Summary: In our study, we explored the popular volcanic caves in the Canary Islands, a hit among those who love ecotourism and geotourism, and also among beachgoers looking for something different to do on their vacation. These six caves, all managed by the island's local authorities, offer a unique adventure but come with their own set of risks, like exposure to radon gas‐a natural hazard in such environments. To keep everyone safe, we delved into the best ways to monitor and manage radon levels, drawing on the latest research and what's been learned from other tourist caves. Our work led to the development of a new plan that fits within current health and safety laws, aimed at reducing any health risks to visitors and staff. This plan is a step forward in making sure that exploring these magnificent caves is not only an unforgettable experience but also a safe one for everyone involved. Key Points: Tourist caves, especially volcanic ones in the Canary Islands, attract many visitors, offering geological and commercial opportunitiesRadon hazards is a major health concern that needs to be considered in the management of underground spaces such as tourist cavesSustainable tourism management requires environmental and cultural responsibility, ensuring the preservation of caves [ABSTRACT FROM AUTHOR]

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The Dismantling and Decommissioning (D&D) of nuclear facilities poses several challenges for radioactivity measurement laboratories involved in environmental radiation monitoring plans. One of them is the definition of the detection limits to be achieved for the radionuclides analysis in different samples. The detection limits should be set in such a way that the obtained concentration values for each radionuclide are easily discriminated from certain maximum activity concentration levels. These maximum activity concentration levels are usually set in view of the respective dose contributions from each radionuclide. There are some national legislations that settle detection limits for drinking water. However, there is no regulation containing detection limits for groundwater or surface water. In this way, different institutions or companies require very different detection limits for radioactivity concentration assessment in those types of water associated with D&D activities. In this work, we focus on the detection limits required for the D&D activities in rainwater, surface water and groundwater. We propose detection limits obtained by applying the WHO methodology for maximum activity concentration levels and compare with those requested by radioactive waste management agencies and regulatory bodies. Some real cases where our proposal allows identification of events are analysed and conclusions are extracted. [ABSTRACT FROM AUTHOR]

Am Fall der Entsorgung radioaktiver Abfälle analysiert der Beitrag, wie Gesellschaften Wissen über ihre Tiefengründe produzieren, um langfristig stabile Entsorgungsszenarien zu entwickeln. Hierzu wird untersucht, wie geologische Formationen in ein solches Entsorgungsvorhaben eingebunden bzw. gar als handlungstragend adressiert werden. Im Zentrum der Untersuchung stehen soziogeologische Relationen im Feld der naturwissenschaftlichen Endlagerforschung. Aus einer soziomateriell orientierten ethnografischen Perspektive wird gezeigt, wie Wirtsgesteinen stabilisierende Fähigkeiten aber auch Anfälligkeiten mit Blick auf Endlagervorhaben zugeschrieben werden. Zudem wird das Experimentieren mit ‚endlagerrelevanten' Materialien in Laboratorien fokussiert. Ziel des Beitrags ist die Formulierung einer Soziologie der Entsorgung im Gefüge von Natur, Technik und Gesellschaft. Based on the case of radioactive waste management, the article analyzes how societies produce knowledge about their undergrounds in order to develop long-term stable disposal scenarios. For this purpose, it is investigated how geological formations are integrated into such disposal projects or even addressed as action-bearing. The focus is on sociogeological relations in the field of scientific repository research. From a sociomaterially oriented ethnographic perspective, the paper discusses how host rocks are attributed stabilizing abilities but also vulnerabilities with regard to repository projects. In addition, experimentation with 'repository-relevant' materials in laboratories will be scrutinised. The aim of the contribution is to formulate a sociology of disposal in an assembly of nature, technology and society. [ABSTRACT FROM AUTHOR]

Deep faults significantly impact the structural stabilities and deformation behaviors of their overburden rocks, which are key factors in underground engineering and geological hazard research. Considering the problem of deep-fault-overburdened breaking during mining of super-thick coal seams and taking the Yaoqiao Coal Mine as the research object, the mining fracture evolution characteristics and overburden displacement law of the non-structured and fault-bearing overburden corresponding to fully mechanized caving mining are compared and analyzed using numerical simulations and physical similarity simulations. The results of this study show the following: 1) The fracture height of the overlying rock presents a specific change law with advancement of the working face; the initial rapid increase to a maximum height of 74 m is achieved when the working face advances to 90 m; with the development of the plastic zone indicating past yield, the fracture height decreases to 54 m and becomes stable, and the final caving angle of the fracture stabilizes at 70°. 2) In coal mining under normal fault conditions, when the working face advances from the upper to lower walls, the roof forms a masonry beam structure that slows down fault activation and crack development. When moving away from the fault, the overburden movements and water-conducting cracks are fewer, and the crack height is lower than that without faults. When approaching the fault, the influence of the faults in the fracture zone increases, and the height of fracture development reaches the maximum value after crossing the fault, highlighting the significant influence of the fault on fracture development. 3) Through a similarity simulation test, it is shown that the overburden caving zone is further compacted by the overburden rock and that the roof collapses in a large range, resulting in rapid upward development of the overburden rock cracks and separation of the central overburden rock cracks that are gradually compacted and closed. These findings are expected to have important theoretical and practical significance for deep underground engineering design, geological disaster prevention, and fault activity monitoring. [ABSTRACT FROM AUTHOR]

Cesium removal from aqueous solutions of radioactive waste streams is a challenge in the field of radioactive waste management; this is due to the small atomic radii of Cs+ metal ions and their high migration ability. So, the development of a withstand system for the removal of Cs+ is crucial. In the current study, the removal of radioactive cesium from aqueous solutions using an RO-TLC membrane was studied. Two modifications were conducted; the first is to enlarge the cesium metal ion radii by interacting with mono- and dibasic acids, namely, stearic acid, tartaric acid, citric acid, and EDTA, and the second is the modification of the RO membrane pore size via reaction with the same acids. The modification was confirmed using SEM, FTIR, and EDX analysis techniques. The Cs+ and K+ rejection capacities and water permeability across the membrane at 1.5 bars were evaluated. Along with using the above-mentioned acids, the Cs+ metal ion retention index (RCs) was also obtained. It was found that employing EDTA as a chelating agent in an amount of 1.5 g/L in conjunction with the variation of feed content since it provided the highest value of RCs ~ 98% when used. Moreover, the elution of Cs+ using water, EDTA, ammonia, and HCl is also investigated. The optimal value of the eluent concentration was (0.25 M) HCl. Finally, Langmuir and Freundlich isotherm models were applied for a better understanding of the sorption process. The results of the present work more closely match the Langmuir isotherm model to determine the dominance of the chemical sorption mechanism. [ABSTRACT FROM AUTHOR]

Nuclear energy production generates nuclear waste. Nuclear and radioactive waste, especially high level waste (HLW) and intermediate level waste (ILW), require special long-term safe management solutions. One part of the solution involves recycling through reprocessing of spent nuclear fuel. Recycling reduces the volume of nuclear waste and allows for the reuse of some of its components. This can be achieved through methods such as adsorption, ion exchange, coagulation, flotation, filtration, chemical precipitation, reverse osmosis, and solvent extraction, like the PUREX process. Another possible future solution involves partitioning and transmutation technology, which can reduce the production of nuclear waste. The best long-term solution is the immobilisation of HLW and ILW in a solid matrix. Materials used for this purpose include glasses, cements, bitumen, geopolymers, concrete, and ceramics as a promising material. While cementation is still the most commonly used immobilisation method due to its low cost and simplicity, vitrification is a more permanent long-term solution. Deep geological disposal in combination with vitrification and a robust multi-barrier system is considered the most acceptable solution for safe nuclear waste isolation. This review provides insight into the mostly commonly used and promising immobilisation materials, as well as the most effective methods and technologies currently in use and under development for the management of HLW and ILW in nuclear waste management. [ABSTRACT FROM AUTHOR]

Due to the susceptibility of microseismic activity to variations in construction parameters and geological conditions, deep-buried tunnel rockbursts often exhibit different precursor characteristics. Consequently, when rockburst intelligent early-warning methods are applied long-term during construction, manual intervention is required to adjust the warning model to maintain accuracy. In light of this issue, this paper focuses on the development of an intelligent dynamic early-warning method for rockbursts, using the Qinling Water Diversion Tunnel of the Hanjiang-to-Weihe Water Diversion Project as a case study. Daily microseismic parameters, construction progress, and records of previously occurred rockbursts serve as input parameters, while the occurrence and intensity level of rockbursts within the next day serve as output parameters. Sequential samples are constructed, and a dynamic early-warning model for rockbursts based on Recurrent Neural Network is established. The dynamic warning capabilities of the model were validated through two test sets, and its mechanism is explained. The results show that the records of occurred rockbursts as input parameters are indispensable. Increasing the sequence length appropriately can improve prediction accuracy. In comparison with other common classification algorithms, the Recurrent Neural Network exhibits superior performance. Ultimately, the model is applied to the long-term rockburst monitoring and early-warning work of the Hanjiang-to-Weihe Water Diversion Project, achieving a rockburst prediction accuracy of 91.2% and a rockburst level prediction accuracy of 86.0%. The findings of this study can provide valuable insights for the research and application of intelligent rockburst early-warning methods. Highlights: An intelligent dynamic early warning model for rockbursts was developed, offering a solution to the dependence on manual intervention. The model incorporates daily microseismic parameters, construction progress, and previous rockburst records as sequential input parameters. By learning from newly acquired rockburst situations and monitoring data, the model dynamically adapts to the ever-changing rockburst conditions. The model demonstrated high prediction accuracy in rockburst occurrence (91.2%) and rockburst level (86.0%) in long-term application. [ABSTRACT FROM AUTHOR]

The study area was defined by geophysical level maps and earthquake parameters. Geophysical measurements were collected from the Mesudiye formation and alluvial units. The seismic Vs–Vp–Vs30, dynamic parameter and electrical resistivity values of the layers were calculated. Vs–Vp–Gmax–σ–Ak and ρ level maps were prepared for depths of 0–5, 5–10, and > 10 m. Seismic Vs30 and groundwater maps were prepared for risk/hazard and liquefaction interpretations, and a risk map was drawn from Ak–Vs30–groundwater maps. In the Mesudiye formation, the average ground amplification value is Ak = 2.21 and according to this value, the danger level is class A and low (Ansal et. all 2004). In alluviums, the average Ak was calculated as 2.51. According to this value, its class is B (medium) and the danger level is medium level. According to the level maps, it was observed that seismic velocities and electrical resistivities increased, and they were compatible with the geological units when passing to the more tight-ground Mesudiye formation from loose-porous-water-saturated alluvial units towards the north and deeper. It was determined that the alluvial grounds with low resistivity (8–30 Ohm m) are moderately corrosive–corrosive; groundwater levels are at ~ 5 m and contain different geological gradations. Therefore, the alluviums were interpreted as a risky area. This interpretation was also proved and supported with the results of the earthquake parameters. It was determined that as the magnitude of the earthquake increased, the probability of a larger earthquake occurred with a longer recurrence year. It was found that the frequency of recurrence of earthquakes with M ≤ 5.5 within 10–50–75–100 years was higher, and M ≥ 6 decreased. For M = 7.4, the average amax = 0.31 g was calculated, and it was determined the liquefaction risk is high hazard, especially in fine-gravel-sandy alluviums (in the south). Therefore, these areas may be more affected by the earthquake. [ABSTRACT FROM AUTHOR]

The largest and the deepest landslides in Serbia occurred on the right valley side of the Danube. General conclusions about landslides along the Danube were obtained on the basis of their comprehensive, detailed investigations: the Sloboda bridge in Novi Sad, the Beška bridge, the large settlement of Bocke, and the high-speed railway viaduct in Čortanovci. These areas are actually large, unstable slopes with deep and shallow landslides. Deep landslides consist of several sliding blocks with 20–40 m in depth. All these landslides were formed in clays and sands of the Pliocene age in the decayed crust of these sediments. The general conclusions about landslides presented in this paper will be of great use for the construction of new facilities in the entire unstable area along the Danube, which is about 100 km in length. [ABSTRACT FROM AUTHOR]

The article discusses the New Voices program established by the US National Academies of Sciences, Engineering, and Medicine (NASEM) in 2018. The program aims to bring diverse and innovative perspectives from early- and mid-career leaders to important discussions on how science, engineering, and medicine shape the global future. The program selects members through a competitive application process and supports them in enhancing scientific and policy solutions to national and global challenges. The article emphasizes the interdisciplinary nature of the program and the importance of inclusivity and diversity in scientific research and policymaking. The program has initiated various projects, including the development of an AI chatbot for organizing and sharing public health information, examining the impact of climate change on engineering design, and promoting science diplomacy and diversity in STEM fields. The program has also provided opportunities for members to engage in NASEM activities and global events, contributing to their career advancement and the advancement of science. The New Voices program is supported by the Gordon and Betty Moore Foundation, the Rutter Foundation, and the Doris Duke Charitable Foundation. [Extracted from the article]

The use of ceramics as matrices for immobilization of radionuclides for the purpose of their safe long-term disposal or useful application is studied with an emphasis placed on phase stability, structural integrity, hydrolytic stability, etc. This work implements a combined approach based on the sol–gel citrate synthesis of nanosized La2Ti2O7 powder and its subsequent spark plasma sintering to produce dense ceramics. The phase composition and structure of the nanosized La2Ti2O7 powder and the ceramic samples obtained in the temperature range of 900–1300°C were studied by powder X-ray diffraction and SEM. It was shown that the conditions of synthesis of the powder ensure the formation of nanosized crystalline La2Ti2O7 grains, consolidation of which under spark plasma heating is accompanied by a change in the phase composition of La2Ti2O7 from a single-phase monoclinic structure to orthorhombic structure with a LaTiO3 impurity at temperatures above 1200°C. It was found that a change in the ceramic structure is accompanied by the formation of non-porous and defect-free monolithic samples. This type of change was shown to lead to an increase in the relative density (81.3–95.7%) and compressive strength (78–566 MPa) of the ceramics. However, the hydrolytic stability decreases, as indicated by increasing La3+ leaching rate from 10–7 to 10–5 g/(cm2 day). The obtained results are useful for the systematic study of materials suitable for immobilization of radioactive waste in ceramics. [ABSTRACT FROM AUTHOR]

Exploring the interplay between the spatial and temporal distribution of geological hazards and the complex hazard-prone environment provides valuable insights for effective management of geological hazards. We analyzed the spatial and temporal distribution characteristics of historical geological hazards in Hunan Province from 2015 to 2022 using standard deviation ellipse, mean nearest neighbor, and kernel density estimation. We also employed three machine learning models to evaluate the susceptibility of geological hazards. Our research reveals that the frequency trends of landslide, debris flow, and collapse over time exhibit highly similar characteristics, and their high-density areas in spatial distribution significantly overlap. Spatial correlation analysis and kernel density estimation show that geological hazards tend to aggregate in certain areas. Central Hunan and its surrounding regions are high-density areas for geological hazards, with the most severe surface collapses occurring in the Loudi area. Geological hazards are more likely to occur at the intersection of various administrative regions, and landslides, in particular, manifest as multi-point distributions, forming a belt around cities—especially in the Hengyang area, surrounded by ridges and mountains. The locus of gravity shift for geological hazards is complex, yet the distance is small, and it primarily concentrates in and around Loudi. Lithology is the most crucial factor affecting geological hazards, followed by elevation and the topographic relief index. The extreme gradient boosting model achieved an AUC value of 0.786, outperforming the random forest and support vector machine models. The susceptibility assessment aligns closely with the kernel density estimation results. This study provides a solid foundation for understanding the spatiotemporal evolution and susceptibility of geological hazards on a local scale, thereby aiding in hazard risk prevention and control. [ABSTRACT FROM AUTHOR]