Search Results (148)

This paper introduces the overall design plan, development timeline, and preliminary progress of the Autonomous Pit Exploration System project. This project aims to develop an advanced multi-robot system for the efficient inspection of nuclear waste-storage tank pits. The project is structured into three phases: Phase 1 involves data collection and interface definition in collaboration with Hanford Site experts and university partners, focusing on tank riser geometry and hardware solutions. Phase 2 includes the selection of sensors and robot components, detailed mechanical design, and prototyping. Phase 3 integrates all components into a cohesive system managed by a master control package which also incorporates digital twin and surrogate models, and culminates in comprehensive testing and validation at a simulated tank pit at the Idaho National Laboratory. Additionally, the system’s communication design ensures coordinated operation through shared data, power, and control signals. For transportation and deployment, an electric vehicle (EV) is chosen to support the system for a full 10 h shift with better regulatory compliance for field deployment. A telescopic arm design is selected for its simple configuration and superior reach capability and controllability. Preliminary testing utilizes an educational robot to demonstrate the feasibility of splitting computational tasks between edge and cloud computers. Successful simultaneous localization and mapping (SLAM) tasks validate our distributed computing approach. More design considerations are also discussed, including radiation hardness assurance, SLAM performance, software transferability, and digital twinning strategies. Full article

Nuclear energy has undergone a significant transformation over the past decades, driven by technological innovation, shifting safety priorities, and the urgent need to mitigate climate change. This study presents a comprehensive review of the historical evolution, current developments, and future prospects of nuclear energy as a strategic low-carbon resource. A structured literature review was conducted following Kitchenham’s methodology, covering peer-reviewed articles and institutional reports from 2000 to 2025. Key advances examined include the deployment of Small Modular Reactors, Generation IV technologies, and fusion systems, along with progress in safety protocols, waste management, and regulatory frameworks. Comparative environmental data confirm nuclear power’s low life-cycle CO₂ emissions and high energy density relative to other generation sources. However, major challenges remain, including high capital costs, long construction times, complex waste disposal, and issues of public acceptance. The analysis underscores that nuclear energy, while not a standalone solution, is a critical component of a diversified and sustainable energy mix. Its successful integration will depend on adaptive governance, international cooperation, and enhanced social engagement. Overall, the findings support the role of nuclear energy in achieving global decarbonization targets, provided that safety, equity, and environmental responsibility are upheld. Full article

Nuclear power is a low-emission and economically competitive energy source, yet the effective disposal and management of its associated radioactive waste can be challenging. Radioactive waste can be categorised as high-level waste (HLW), intermediate-level waste (ILW), and low-level waste (LLW). LLW primarily comprises materials contaminated during routine clean-up, such as mop heads, paper towels, and floor sweepings. While LLW is less radioactive compared to HLW and ILW, the management of LLW poses significant challenges due to the large volume that requires processing and disposal. The volume of LLW can be significantly reduced through sorting, which is typically performed manually in a labour-intensive way. Smart management techniques, such as computer vision (CV) and machine learning (ML), have great potential to help reduce the workload and human errors during LLW sorting. This paper provides a comprehensive review of previous research related to LLW sorting and a summative review of existing applications of CV in solid waste management. It also discusses state-of-the-art CV and ML algorithms and their potential for automating LLW sorting. This review lays a foundation for and helps facilitate the applications of CV and ML techniques in LLW sorting, paving the way for automated LLW sorting and sustainable LLW management. Full article

Some of nuclear power’s primary detractors are the unique environmental challenges and impacts of radioactive wastes generated during fuel cycle operations. Key benefits of spent fuel reprocessing (SFR) are reductions in primary high active waste (HAW) masses, volumes, and lengths of radiotoxicity at the expense of secondary waste generation and high capital and operational costs. By employing advanced waste management and resource recovery concepts in SFR beyond the existing standard PUREX process, such as minor actinide and fission product partitioning, these challenges could be mitigated, alongside further reductions in HAW volumes, masses, and duration of radiotoxicity. This work assesses various current and proposed SFR and fuel cycle options as base cases, with further options for fission product partitioning of the high heat radionuclides (HHRs), rare earths, and platinum group metals investigated. A focus on primary waste outputs and the additional energy that could be generated by the reprocessing of high-burnup PWR fuel from Gen III(+) reactors using a simple fuel cycle model is used; the effects of 5- and 10-year spent fuel cooling times before reprocessing are explored. We demonstrate that longer cooling times are preferable in all cases except where short-lived isotope recovery may be desired, and that the partitioning of high-heat fission products (Cs and Sr) could allow for the reclassification of traditional raffinates to intermediate level waste. Highly active waste volume reductions approaching 50% vs. PUREX raffinate could be achieved in single-target partitioning of the inactive and low-activity rare earth elements, and the need for geological disposal could potentially be mitigated completely if HHRs are separated and utilised. Full article

Nuclear energy can help stop climate change by generating large amounts of emission-free electricity. Nuclear reactor designs are continually being developed to be more fuel efficient, safer, easier to construct, and to produce less nuclear waste. The term advanced nuclear reactors refers either to Generation III+ and Generation IV or small modular reactors. Every reactor is associated with the nuclear fuel cycle that must be economically viable and competitive. An important matter is optimization of fissile materials used in reactor and/or reprocessing of spent fuel and reuse. Currently operating reactors use the open cycle or partially closed cycle. Generation IV reactors are intended to play a significant role in reaching a fully closed cycle. At the same time, we can observe the growing interest in development of small modular reactors worldwide. SMRs can adopt either fuel cycle; they can be flexible depending on their design and fuel type. Spent nuclear fuel management should be an integral part of the development of new reactors. The proper management methods of the radioactive waste and spent fuel should be considered at an early stage of construction. The aim of this paper is to highlight the challenges related to reprocessing of new forms of nuclear fuel. Full article

This study examines methods to improve the energy efficiency of radiofrequency inductively coupled plasma (RF-ICP) torches for radioactive waste treatment, with a focus on surpassing the typical energy efficiency limit of approximately 70%. To improve energy efficiency and plasma performance, this research investigates the transition from axial gas flow to vortex gas flow patterns using COMSOL Multiphysics software v6.2. Key plasma parameters, including energy efficiency, number of gas vortices, heat transfer, and temperature distribution, were analyzed to evaluate the improvements. The results indicate that adopting a vortex flow pattern increases energy conversion efficiency, increases heat flux, and reduces charge losses. Furthermore, optimizing the torch body design, particularly the nozzle, chamber volume, and gas entry angle, significantly improves plasma properties and energy efficiency by up to 90%. Improvements to RF-ICP torches positively impact waste decomposition by creating better thermal conditions that support resource recovery and potential material recycling. In addition, these improvements contribute to reducing secondary waste, mitigating environmental risks, and fostering long-term public support for nuclear technology, thereby promoting a more sustainable approach to waste management. Simulation results demonstrate the potential of RF-ICP flares as a cost-effective and sustainable solution for the thermal treatment of low- to intermediate-level radioactive waste. Full article

Powder injection molding (PIM) has been used to produce nearly net-shaped samples of tungsten-based alloys. These alloys have been previously shown to have favorable characteristics when compared with standard ITER-grade tungsten. Six different alloys were produced with this method: W-1TiC, W-2Y₂O₃, W-3Re-1TiC, W-3Re-2Y₂O₃, W-1HfC and W-1La₂O₃-1TiC. These were tested alongside ITER-grade tungsten in the PSI-2 linear plasma device under ITER-relevant plasma and heat loads to assess their suitability for use in a fusion reactor. All materials showed good behavior when exposed to the lower pulse number tests (≤1000 ELM-like pulses), although standard tungsten performed slightly better, with no observable difference in surface roughness. High-power shots, namely one laser pulse of 1.6 GWm⁻², revealed that samples containing yttria are more prone to melting and droplet ejection. After high pulse number tests (10,000 and 100,000 pulses), with and without plasma, the reference tungsten showed the most cracking and highest surface roughness of all materials, while the PIM samples seemed to have a higher resistance to cracking. This can be attributed to the higher ductility of these alloys, particularly those containing rhenium. This means that tungsten-based alloys, whether produced via PIM or other methods, could potentially be used in certain areas of a fusion reactor. Full article

Efficient real-time isotope identification is a critical challenge in nuclear spectroscopy, with important applications such as radiation monitoring, nuclear waste management, and medical imaging. This work presents a novel approach for isotope classification using a System-on-Chip FPGA, integrating hardware-accelerated principal component analysis (PCA) for feature extraction and a software-based random forest classifier. The system leverages the FPGA’s parallel processing capabilities to implement PCA, reducing the dimensionality of digitized nuclear signals and optimizing computational efficiency. A key feature of the design is its ability to perform real-time classification without storing ADC samples, directly processing nuclear pulse data as it is acquired. The extracted features are classified by a random forest model running on the embedded microprocessor. PCA quantization is applied to minimize power consumption and resource usage without compromising accuracy. The experimental validation was conducted using datasets from high-resolution pulse-shape digitization, including closely matched isotope pairs (¹²C/¹³C, ³⁶Ar/⁴⁰Ar, and ⁸⁰Kr/⁸⁴Kr). The results demonstrate that the proposed SoC FPGA system significantly outperforms conventional software-only implementations, reducing latency while maintaining classification accuracy above 98%. This study provides a scalable, precise, and energy-efficient solution for real-time isotope identification. Full article

Tritium is a radioisotope that is extremely mobile in the biosphere and that can be transferred to the environment and to humans mainly via tritium oxide or tritiated water. Moreover, as is widely known, it is extremely difficult to detect in the environment. In the last decade, many studies and research activities have been performed to fill the knowledge gap on this radionuclide, the amount of which is expected to be increasingly released into the environment from nuclear installations in the near future. Considering this and the fact that the biological and environmental effects produced by tritium have been examined mainly from a medical and detection monitoring point of view, it is considered important to propose in this study a review of the critical aspects of tritium from the environmental, engineering, and waste management points of view. Identifying sources and effects of tritium, tritium materials and wastes containing tritium in the environment is also fundamental for planning the specific and necessary actions required for an effective waste management approach under, e.g., disposal conditions. The critical analysis of the published recent studies has allowed to evaluate, for example, that the expected rate of tritium generation in a fusion reactor is four orders of magnitude higher than that of LWRs, and the environmental release from a fusion reactor is 1.4–2.2‱, which is twice as much as from a heavy water reactor and more than two orders of magnitude higher than from a LWRs. Furthermore, with reference to the waste management strategy, it is emphasized, e.g., that the condensation of moisture inside vaults and the interaction of H₂O with the disposal body determine the formation of tritiated water, which is filtered through the concrete and eventually released into the environment. Consequently, in the selection of engineered barrier materials for repositories/disposal facilities, the use of a mixture of a framework and layered silicates is proposed to improve its absorption and filtering properties. Full article

¹³⁷Cs is a persistent β/γ-emitter (t_1/2 = 30.1 years) generated from ²³⁵U and ²³⁹Pu fission. It is a critical challenge to efficiently capture ¹³⁷Cs⁺ for nuclear waste management due to its high solubility, environmental mobility, and propensity for biological accumulation. Herein, we prepare a two-dimensional (2D) thiotitanate Rb_0.32TiS₂·0.75H₂O (denoted Rb-TiS₂) using a special molten salt synthesis method, “Mg + RbCl”. Rb-TiS₂ can selectively capture Cs⁺ from aqueous solutions. Its structure features a flexible anionic thiotitanate layer with Rb⁺ as counter ions located at the interlayer spaces. As an ion exchanger, it possesses high adsorption capacity (q_m^Cs = 232.70 mg·g⁻¹), rapid kinetics (the removal rate R > 72% within 10 min), and a wide pH tolerance range (pH = 4–12) for Cs⁺ adsorption. Through a single-crystal X-ray structural analysis, we elucidated the mechanism of Cs⁺ capture, revealing the ion exchange pathways between Cs⁺ and Rb⁺ in Rb-TiS₂. This work not only provides an important reference for the synthesis of transition metal sulfides with alkali metal cations but also proves the application prospect of transition metal sulfides in radionuclide remediation. Full article

Copper has been proposed as a container material for the disposal of used nuclear fuel in a number of countries worldwide. The container materials will be subject to various corrosion processes in a deep geological repository, including radiation-induced corrosion (RIC) resulting from the γ-irradiation of the near-field environment. A comprehensive model is being developed to predict the extent of RIC by coupling a radiolysis model to the interfacial electrochemical reactions on the container surface. An important component of the overall model is a radiolysis model to predict the time-dependent concentration of oxidizing and reducing radiolysis products. As a first step in the model development, various radiolysis models have been validated against experimental measurements of the concentrations of dissolved and gaseous radiolysis products. Experimental data are available for pure H₂O- and Cl⁻-containing solutions, with and without a gas headspace. The results from these experiments have been compared with predictions from corresponding radiolysis models, including the effects of the partitioning of gaseous species (O₂ and H₂) at the gas–solution interface. Different reaction schemes for the Cl⁻ radiolysis models are also compared. The validated radiolysis model will then be coupled with interfacial reactions on the copper surface and additional processes related to the presence of bentonite clay in Steps 2 and 3 of the overall model, respectively. Full article

Development of a defensible source-term model (STM), usually a thermodynamical model for radionuclide solubility calculations, is critical to a performance assessment (PA) of a geologic repository for nuclear waste disposal. Such a model is generally subjected to rigorous regulatory scrutiny. In this article, we highlight key guiding principles for STM model development and validation in nuclear waste management. We illustrate these principles by closely examining three recently developed thermodynamic models with the Pitzer formulism for aqueous H⁺—Nd³⁺—NO₃⁻(—oxalate) systems in a reverse alphabetical order of the authors: the XW model developed by Xiong and Wang, the OWC model developed by Oakes et al., and the GLC model developed by Guignot et al., among which the XW model deals with trace activity coefficients for Nd(III), while the OWC and GLC models are for concentrated Nd(NO₃)₃ electrolyte solutions. The principles highlighted include the following: (1) Principle 1. Validation against independent experimental data: A model should be validated against experimental data or field observations that have not been used in the original model parameterization. We tested the XW model against multiple independent experimental data sets including electromotive force (EMF), solubility, water vapor, and water activity measurements. The results show that the XW model is accurate and valid for its intended use for predicting trace activity coefficients and therefore Nd solubility in repository environments. (2) Principle 2. Testing for relevant and sensitive variables: Solution pH is such a variable for an STM and easily acquirable. All three models are checked for their ability to predict pH conditions in Nd(NO₃)₃ electrolyte solutions. The OWC model fails to provide a reasonable estimate for solution pH conditions, thus casting serious doubt on its validity for a source-term calculation. In contrast, both the XW and GLC models predict close-to-neutral pH values, in agreement with experimental measurements. (3) Principle 3. Honoring physical constraints: Upon close examination, it is found that the Nd(III)-NO₃ association schema in the OWC model suffers from two shortcomings. Firstly, its second stepwise stability constant for Nd(NO₃)₂⁺ (log K₂) is much higher than the first stepwise stability constant for NdNO₃²⁺ (log K₁), thus violating the general rule of (log K₂–log K₁) < 0, or $\frac{K_1}{K_2}>1$. Secondly, the OWC model predicts abnormally high activity coefficients for Nd(NO₃)₂⁺ (up to ~900) as the concentration increases. (4) Principle 4. Minimizing degrees of freedom for model fitting: The OWC model with nine fitted parameters is compared with the GLC model with five fitted parameters, as both models apply to the concentrated region for Nd(NO₃)₃ electrolyte solutions. The latter appears superior to the former because the latter can fit osmotic coefficient data equally well with fewer model parameters. The work presented here thus illustrates the salient points of geochemical model development, selection, and validation in nuclear waste management. Full article

Radiolysis of water and aqueous solutions refers to the decomposition of water and its solutions under exposure to ionizing radiation, such as γ-rays, X-rays, accelerated particles, or fast neutrons. This exposure leads to the formation of highly reactive species, including free radicals like hydroxyl radicals (^●OH), hydrated electrons (e⁻_aq), and hydrogen atoms (H^●), as well as molecular products like molecular hydrogen (H₂) and hydrogen peroxide (H₂O₂). These species may further react with each other or with solutes in the solution. The yield and behavior of these radiolytic products depend on various factors, including pH, radiation type and energy, dose rate, and the presence of dissolved solutes such as oxygen or ferrous ions, as in the case of the ferrous sulfate (Fricke) dosimeter. Aqueous radiation chemistry has been pivotal for over a century, driving advancements in diverse fields, including nuclear science and technology—particularly in water-cooled reactors—radiobiology, bioradical chemistry, radiotherapy, food preservation, wastewater treatment, and the long-term management of nuclear waste. This field is also vital for understanding radiation effects in space. Full article

Nuclear energy has a great impact on the global energy mix. In Spain, it supplies over 20% of current energy requirements, demonstrating the relevance of nuclear power plants. These plants generate different types of waste (apart from radioactive) that should be managed. For instance, the activated carbon included in filters (which neutralize isotopes in a possible radioactive leakage) should be periodically replaced. Nevertheless, these activated carbons might present long service lives, as they have not undergone any adsorption processes. Consequently, a considerable amount of activated carbon can be reused in alternative processes, even in the same nuclear power plant. The aim of this work was to assess the use of activated carbons (previously included in filters to prevent possible radioactive releases in primary circuits) for water treatment derived from the steam cycle of a nuclear power plant. A regeneration process (boron removal) was carried out (with differences between untreated carbon and after treatments, from S_BET = 684 m² g⁻¹ up to 934 m² g⁻¹), measuring the adsorption efficiency for ethanolamine and triton X-100. There were no significative results that support the adsorption effectiveness of the activated carbon tested for ethanolamine adsorption, whereas a high adsorption capacity was found for triton X-100 (q_L1 = 281 mg·g⁻¹), proving that factors such as porosity play an important role in the specific usage of activated carbons. Full article

The Chalk River Laboratories (CRL) site in Ontario, Canada, has long been a hub for nuclear research, which has resulted in the accumulation of legacy nuclear waste, including radioactive materials such as uranium, plutonium, and other radionuclides. Effective management of this legacy requires precise contamination and risk assessments, with a particular focus on the concentration levels of fissile materials such as ${}^{235}\mathrm{U}$. These assessments are essential for maintaining nuclear criticality safety. This study estimates the upper bounds of ${}^{235}\mathrm{U}$ concentrations. We investigated the use of a hybrid parametric bootstrapping method and robust statistical techniques to analyze datasets with outliers, then compared these outcomes with those derived from nonparametric bootstrapping. This study underscores the significance of measuring ${}^{235}\mathrm{U}$ for ensuring safety, conducting environmental monitoring, and adhering to regulatory compliance requirements at nuclear legacy sites. We used publicly accessible ${}^{235}\mathrm{U}$ data from the Eastern Desert of Egypt to demonstrate the application of these statistical methods to small datasets, providing reliable upper limit estimates that are vital for remediation and decommissioning efforts. This method seeks to enhance the interpretation of sensor data, ultimately supporting safer nuclear waste management practices at legacy sites such as CRL. Full article