Use Of Liquid Metals Research Articles

Technique of Reactor Experiments of Tin-Lithium Alloy Interaction with Hydrogen Isotopes Under Neutron Irradiation Conditions

The implementation of the ITER and DEMO projects currently includes the investigation of the structural and functional material properties of fusion reactors (FRs). Research to support the use of liquid metals and alloys as plasma-facing materials (PFMs) is a crucial area of work during the development of new FRs. Recent studies indicate the prospects of the tin-lithium (Sn-Li) alloy as a new liquid metal for protecting the in-vessel elements of a FR from the energy flows and high-density particles. Sn-Li alloy has been widely explored for utilization as PFM; however, there is a shortage of investigations being performed at nuclear reactors. The utilization of Sn-Li alloy as PFM in a FR must be fully justified by validated experimental results on tests under extremely high heat, plasma, and radiation loads. The paper presents the methodology of in-pile experiments performed at the IVG.1M research reactor (Kurchatov, Kazakhstan) to study the interaction of hydrogen isotopes with Sn-Li alloy under neutron irradiation conditions. A Sn-Li sample with 73 at. % tin and 27 at. % lithium was manufactured. A unique experimental ampoule device (AD) with a Sn-Li sample had been developed and manufactured for in-pile tests. The results of neutron-physical and thermophysical calculations of designs of the experimental device with Sn-Li alloy under irradiation conditions of the IVG.1M reactor were performed to justify the AD design. Methodical experiments were performed to determine the temperature dependence of the change in the composition of the gas phase in the chamber with Sn-Li alloy. The time dependence of the partial pressure of hydrogen, tritium, and tritium-containing molecules in the AD volume with the Sn-Li alloy on its temperature under reactor irradiation conditions at a power of 3 MW has been studied. Key findings include the successful measurement of tritium release, the determination of temperature conditions for tritium generation and release, and the validation of our experimental AD for conducting such studies.

High-performance liquid metal electromagnetic actuator fabricated by femtosecond laser

Small-scale electromagnetic soft actuators are characterized by a fast response and simple control, holding prospects in the field of soft and miniaturized robotics. The use of liquid metal (LM) to replace a rigid conductor inside soft actuators can reduce the rigidity and enhance the actuation performance and robustness. Despite research efforts, challenges persist in the flexible fabrication of LM soft actuators and in the improvement of actuation performance. To address these challenges, we developed a fast and robust electromagnetic soft microplate actuator based on a laser-induced selective adhesion transfer method. Equipped with unprecedentedly thin LM circuit and customized low Young’s modulus silicone rubber (1.03 kPa), our actuator exhibits an excellent deformation angle (265.25°) and actuation bending angular velocity (284.66 rad·s−1). Furthermore, multiple actuators have been combined to build an artificial gripper with a wide range of functionalities. Our actuator presents new possibilities for designing small-scale artificial machines and supports advancements in ultrafast soft and miniaturized robotics.

Unlocking the Potential of Magnetic Refrigeration: Investigating the Compatibility of the Ga-Based Liquid Metal with a La(Fe,Mn,Si)13Hz Magnetocaloric Material for Enhanced Long-Term Stability.

Magnetic refrigeration (MR) is a cutting-edge technology that promises high energy efficiency and eco-friendliness, making it an exciting alternative to traditional refrigeration systems. However, the main challenge to its widespread adoption is cost competitiveness. In this context, the use of liquid metals as heat transfer liquids in the MR has been proposed as a game-changing solution. Unfortunately, the toxicity and flammability of these liquid metals have raised serious concerns, limiting their practical use. In this study, we investigate the compatibility of a nontoxic and nonflammable GaInSn-based liquid metal with a magnetocaloric material, La(Fe,Mn,Si)13Hz, over a 1.5 year period. Our findings reveal nearly a 14% reduction in specific cooling energy and peak-specific isothermal magnetic entropy change for the considered magnetocaloric material. Our study provides valuable insights into the long-term stability of magnetocaloric materials and their compatibility with liquid metals, facilitating the development of more cost-effective and sustainable MR systems.

A perspective on high‐temperature heat storage using liquid metal as heat transfer fluid

AbstractEnergy storage systems are essential to secure a reliable electricity and heat supply in an energy system with high shares of fluctuating renewable energy sources. Thermal energy storage systems offer the possibility to store energy in the form of heat relatively simply and at low cost. In concentrating solar power systems, for instance, molten salt‐based thermal storage systems already enable a 24/7 electricity generation. The use of liquid metals as heat transfer fluids in thermal energy storage systems enables high heat transfer rates and a large operating temperature range (100°C to >700°C, depending on the liquid metal). Hence, different heat storage solutions have been proposed in the literature, which are summarized in this perspective. Based on these, future technical advances are suggested such as reducing the liquid metal share in the heat storage, using waste material as storage medium or using liquid metal as heat transfer fluids not only in sensible, but in latent or thermochemical energy storage systems. The use of waste material in a packed bed configuration with 5% porosity, for example, can bring down the storage material costs to 2%–3% of the costs of a liquid metal‐only storage system. Furthermore, future application fields beyond concentrating solar power are proposed: supply of industrial process heat, waste heat integration and power‐to‐heat‐to‐power processes.

Flexible Microcircuit of a Liquid Metal Deposit Layer

AbstractLiquid metal (LM) is of great use in many fields (e. g., sensors, biology, electronic circuits). With special mobility, high surface tension and excellent electrical conductivity, it can play a role in the field of flexible electronics. Due to its surface tension, it easily shrinks into a spheroid shape. Especially under the same current condition, the shrinkage of the volume will lead to open circuit, so it is very difficult to produce stable liquid metal ultrathin, ultrafine wire, which has become a barrier limiting the use of liquid metal. In this work, LM is mixed with polydimethylsiloxane to form a micrometer‐thick conductive layer by free deposition. The LM is located inside the polymer holes. Not only that, microcircuits are also mapped on the surface of LM deposits. It not only has excellent electrical conductivity, but also has good flexibility. This work explores a simple method to produce a ultrathin conductive film and reduce the size of electronic components, which has potential applications in integrated circuits.

High-Fidelity Modeling and Experiments to Inform Safety Analysis Codes for Heat Pipe Microreactors

Heat pipe microreactors are reactor designs that primarily use liquid-metal heat pipes to cool the core. The main interest in heat pipes is the fact that they can remove heat passively. This, along with the use of liquid metal, allows the reactor to operate at higher temperatures. Although the use of heat pipes in nuclear reactors is new, liquid-metal heat pipe technology is mature. Nevertheless, experimental data on heat pipes are scarce, and very little is known about their behavior during abnormal operations and close to their thermal limits. Therefore, new experiments and accurate heat pipe simulations are needed to develop reliable closure models. This work describes a joint experimental and numerical investigation into heat pipes that attempts an initial closure of this gap. The numerical and experimental efforts are currently proceeding in parallel, aimed at different aspects of heat pipes. The numerical part is focused on gaps in local closures, and the experiments capture the overall heat pipe behavior.

Liquid metal-based soft, hermetic, and wireless-communicable seals for stretchable systems.

Soft materials tend to be highly permeable to gases, making it difficult to create stretchable hermetic seals. With the integration of spacers, we demonstrate the use of liquid metals, which show both metallic and fluidic properties, as stretchable hermetic seals. Such soft seals are used in both a stretchable battery and a stretchable heat transfer system that involve volatile fluids, including water and organic fluids. The capacity retention of the battery was ~72.5% after 500 cycles, and the sealed heat transfer system showed an increased thermal conductivity of approximately 309 watts per meter-kelvin while strained and heated. Furthermore, with the incorporation of a signal transmission window, we demonstrated wireless communication through such seals. This work provides a route to create stretchable yet hermetic packaging design solutions for soft devices.

Low‐Temperature CO2 Reduction using Mg–Ga Liquid Metal Interface

AbstractThe need for effective and adaptive technologies for carbon dioxide (CO2) mitigation targeting global net‐zero carbon emissions is critically growing. Hence, innovative technologies for CO2 reduction have attracted worldwide interest from scientific research communities. The use of liquid metals for the conversion of CO2 into carbon or solid carbonaceous products has gained increasing attention in recent years due to their high activity and resistance to coking. Here, a facile approach for the reduction of CO2 to solid carbon using liquid Mg at and near room temperature, and atmospheric pressure is presented. In this process, magnesium (Mg) plays a major role in driving the dissociation of CO2 to its elemental constituents, carbon and oxygen. During the reaction process, Mg ions dissolve in gallium (Ga) liquid metal alloy, diffuse to the gas–liquid interface, and reduce CO2 to carbon while undergoing an oxidation reaction. The electrochemical method ensures a sustainable cyclic process by reducing Mg and Ga ions back to their metallic counterpart. The use of liquid metal alloys for CO2 reduction reactions can enable to achieve CO2 capture and storage at room temperature, setting a new foundation for the future exploration of efficient CO2 mitigation issues.

MXene-Reinforced Liquid Metal/Polymer Fibers via Interface Engineering for Wearable Multifunctional Textiles.

Stretchable conductive fibers are an important component of wearable electronic textiles, but often suffer from a decrease in conductivity upon stretching. The use of liquid metal (LM) droplets as conductive fillers in elastic fibers is a promising solution. However, there is an urgent need to develop effective strategies to achieve high adhesion of LM droplets to substrates and establish efficient electron transport paths between droplets. Here, we use large-sized MXene two-dimensional conductive materials to modify magnetic LM droplets and prepare MXene/magnetic LM/poly(styrene-butadiene-styrene) composite fibers (MLMS fibers). The MXene sheets decorated on the surface of magnetic LM droplets not only enhance the droplet adhesion to substrate but also bridge adjacent droplets to establish efficient conductive paths. MLMS fibers show several-fold improvements in tensile strength and elongation and a 30-fold increase in conductivity compared with pure LM-filled fibers. These conductive fibers can be easily woven into multifunctional textiles, which exhibit strong electromagnetic interference shielding and stable Joule heating performances even under large tensile deformation. In addition, other advantages of MLMS textiles, such as high gas/liquid permeability, strong chemical resistance (acid and alkaline conditions), high/low-temperature tolerance (-40-150 °C) and water washability, make them particularly suitable for wearable applications.

Monolithically Programmed Stretchable Conductor by Laser-Induced Entanglement of Liquid Metal and Metallic Nanowire Backbone.

Owing to its low mechanical compliance, liquid metal is intrinsically suitable for stretchable electronics and future wearable devices. However, its invariable strain-resistance behavior according to the strain-induced geometrical deformation and the difficulty of circuit patterning limit the extensive use of liquid metal, especially for strain-insensitive wiring purposes. To overcome these limitations, herein, novel liquid-metal-based electrodes of fragmented eutectic gallium-indium alloy (EGaIn) and Ag nanowire (NW) backbone of which their entanglement is controlled by the laser-induced photothermal reaction to enable immediate and direct patterning of the stretchable electrode with spatially programmed strain-resistance characteristics are developed. The coexistence of fragmented EGaIn and AgNW backbone, that is, a biphasic metallic composite (BMC), primarily supports the uniform and durable formation of target layers on stretchable substrates. The laser-induced photothermal reaction not only promotes the adhesion between the BMC layer and substrates but also alters the structure of laser-irradiated BMC. By controlling the degree of entanglement between fragmented EGaIn and AgNW, the initial conductivity and local gauge factor are regulated and the electrode becomes effectively insensitive to applied strain. As the configuration developed in this study is compatible with both regimes of electrodes, it can open new routes for the rapid creation of complex stretchable circuitry through a single process.

Numerical simulation of a low Prandtl number flow over a backward facing step with an anisotropic four-equation turbulence model

In recent years the use of liquid metals has become more and more popular for heat transfer applications in many fields ranging from IV generation fast nuclear reactors to solar power plants. Due to their low Prandtl number values, the similarity between dynamical and thermal fields cannot be assumed and sophisticated heat turbulence models are required to take into account the anisotropy of the turbulent heat transfer involving liquid metals. In the present work, we solve an anisotropic four-equation turbulence model coupled with the Reynolds Averaged Navier Stokes system of equations to simulate a turbulent flow of liquid sodium over a vertical backward-facing step. We implement an explicit algebraic model for Reynolds stress tensor and turbulent heat flux that takes into account flow anisotropic behavior. We study forced and mixed convection regimes when a uniform heat flux is applied on the wall behind the step. Linear isotropic approximations for eddy viscosity and eddy thermal diffusivity underestimate the turbulent heat flux components while this anisotropic model shows a better agreement with DNS results.

Theoretical modeling of a vortex-type liquid metal MHD generator for energy harvesting applications

The use of liquid metals (LM) in energy harvesting is gaining attention due to their unique properties. The DC vortex magnetohydrodynamic (MHD) generator is a suitable and robust option among the different approaches in which LM can be used for energy scavenging. In this device, the LM is driven in a cylindrical chamber to produce a swirling flow, which interacts with an external magnetic field, inducing electric currents that can be extracted to power an external electric system. In turn, the electrical resistance of this system highly affects the dynamics of the flow and the electric variables. In this work, two analytical models for the total voltage, electric current, electric and fluid power are developed. One model considers an inviscid fluid performing a rigid solid rotation. The second model considers a real fluid, for which the velocity distribution is also determined. For this latter case, MHD induced effects are modeled. These solutions are also obtained in dimensionless form in terms of the interaction parameter, Reynolds number and Hartmann number. In addition, 2D and 3D numerical models were implemented. These models are compared with reported experimental results, obtaining a good qualitative and quantitative agreement (differences ⩽13.5%) with numerical and analytical results.

Analysis and evaluation of liquid metal anode target material of transmission X-ray tube

In recent years, due to the fluidity and thermal conductivity of the liquid metal, the use of liquid metal as an anode target is one of the ways to improve the brightness of X-ray tubes. In this paper, the optimal thickness and conversion efficiency of three kinds of target materials under different energies were discussed by the Monte Carlo method. The optimal thickness of the gallium target is 6.2 μm when the incident electron beam energy is 50 keV and the optimal thickness of the indium target and the tin target was 4 μm. The X-ray conversion efficiency of the gallium target was 44.28% higher than that of the silver target as well as the ratio of X-ray count with the K lines to total count was 53.38%. The gallium target is suitable to be the material of a liquid metal anode target of transmission X-ray tube within the concerned energy range.

Design of Microfluidic Reflectarray Elements for Multi-Reconfiguration Using Liquid Metal

Using an alloy of non-toxic liquid metal (Galinstan) is proposed to implement multi-reconfiguration in reflectarray elements. Reflectarray antennas are an interesting technology for dynamically controlling, simultaneously or individually, different properties of the antenna (beam shape and pointing direction, field polarization, and frequency of operation) according to the system’s demand. The use of liquid metal, which can potentially be used to re-shape the topology of the unit cell, along with advances in the micro-and nanofluidics field, provides more flexibility for efficiently implementing such multi-reconfiguration. A frequency-reconfigurable reflectarray element is based on the well-known aperture-coupled cell, and a phase-reconfigurable cell based on single-and multi-resonance dipoles is proposed at 28 GHz. One advantage of microfluidics is that the concept can easily be extended to much higher frequencies, where other devices start to be expensive, inefficient, or limited in terms of multi-reconfiguration. The microfluidic technology required to implement the dipole-based element is demonstrated using a microfluidic burst-valve chip. Additionally, a simplified RF proof-of-concept is presented using the well-known waveguide simulator technique from 15 GHz to 22 GHz (WR51). The results obtained constitute an important first step toward the implementation of multi-reconfigurable reflectarray antennas.

Comparative Analysis of Lithium First Wall Concepts for Tokamak with Reactor Technologies

When developing the stationary fusion reactor, an unresolved issue is the design of its intra-chamber plasma-facing elements. It has now become obvious that among the materials conventionally used for intra-chamber elements, there are no solid structural materials that would meet the requirements for the long-term operation under the effect of the flux of fusion neutrons (14 MeV) with a density of ~1014 cm–2 s–1 and the heat flux with a power density of 10–20 MW/m2. An alternative solution to this problem is the use of liquid metals as a plasma-facing materials, and, first of all, the use of lithium, which has a low atomic number (low charge number Z). Other easily-melting metals are also considered, which have higher Z number, but lower saturation vapor pressure than lithium. This will make it possible to create the long-lived, heavy-to-damage and self-renewing surface of the intra-chamber elements, which will not contaminate the plasma. The main ideas of the alternative concept of the intra-chamber elements can be formulated based on the comprehensive analysis of the problems and requirements arising during the development of intra-chamber elements of the stationary reactor, for example, the DEMO-type reactor. The article presents the analysis of the possible design of the lithium-coated intra-chamber elements and discusses the main ideas of the lithium first wall concept for the tokamak with reactor technologies.

Liquid Metal-Derived Two-Dimensional Layered Double Oxide Nanoplatelet-Based Coatings for Electromagnetic Wave Absorption

Room-temperature liquid metals offer intriguing chemistry for obtaining atomic nanomaterials with unique composition and morphologies. However, the use of liquid metals for the synthesis of layered double oxide (LDO) materials has rarely been reported. When surrounded with water, liquid metal alloys produce low-dimensional hydroxides on their interfacial regions. In this work, highly electrostatically polarized two-dimensional (2D) aluminum hydroxides, featuring OH bonds, are devised as adsorption sites for divalent cations including Ni2+, Co2+, Mg2+, Mn2+, Zn2+, and Fe2+ ions. For Ni2+ and Co2+ ions, remarkably, through changing synthesis conditions, different orientations of 2D Al/NiCo-LDO nanoplatelets can be synthesized. The change in the orientation of the surface platelets, that is, parallel or vertical, to the plane of aluminum oxide resulted in excellent electromagnetic wave (EW) absorption performance. The effective absorption bandwidth reaches 5.61 GHz at a composite thickness of only 1.7 mm. The different nanomorphology and annealing temperature of Al/NiCo-LDO resulted in fundamentally different electromagnetic losses. Results indicating the developed framework have tunable and excellent EW absorption capabilities. 2D Al/NiCo-LDOs prepared by the developed liquid metal synthesis method shows a great promise for applications in the fields of EW absorption and electromagnetic protection. Due to their lightweight, high-surface-area, and mechanically strong material features, aluminum oxide compounds are suitable for the synthesis of other LDO compounds including Mg2+, Mn2+, Zn2+, and Fe2+. The incorporation of a variety of divalent cations into the nanostructure and facet engineering are promising pathways for the production of reinforced lightweight nanomaterials for utilization in various applications. This work fundamentally explores the effect of achieved materials' polarization through fully characterizing the absorption.

Conceptual design of Thomson scattering diagnostics for the COMPASS-U tokamak.

The Thomson scattering (TS) diagnostic, one of the key diagnostics used on the tokamaks around the world, is planned for the COMPASS-U tokamak, which is recently under design and construction in the Institute of Plasma Physics in Prague, Czech Republic. This tokamak is supposed to be a world-unique, high magnetic field device with hot walls, allowing for the study of the plasma exhaust in advanced operational scenarios and testing cutting-edge technologies relevant to future fusion reactors, e.g., use of liquid metals. The core and edge TS systems are planned to be designed and operational, with a limited performance, already in the early stage of the tokamak operation. In this contribution, requirements and the most important constraints defining the TS system design are presented. The impact of both the possible collection lens location and spatial resolution on the plasma pedestal observation is simulated. Design considerations also take into account the high-resolution TS core and edge systems available from the COMPASS tokamak, which will be reused. The collection lenses will be newly built. Extension of the detection system will complete the plasma radius coverage in the future. The divertor TS is considered for later periods.

ТЕПЛОФИЗИЧЕСКИЕ ИССЛЕДОВАНИЯ: ОТ ПЕРВОГО СТЕНДА К КРУПНОМАСШТАБНОЙ АТОМНОЙ ЭНЕРГЕТИКЕ

The article presents the main research results of thermal physicists of the IPPE from its inception to the present time. Research results in the areas of heat and mass transfer and hydrodynamics of coolants (liquid metals, water), physical chemistry and technology of liquid metal coolants for nuclear power plants for various purposes (nuclear power plants, nuclear submarines, space nuclear power plants), development codes, innovative projects, non-nuclear technologies for the use of liquid metals, heat pipes, analysis and generalization of thermophysical data are considered in the article. As a result of a large complex of experimental and computational studies, the fundamental physicochemical and thermohydraulic regularities of the coolant - impurities - structural materials - protective gas have been studied, scientific foundations have been created for the use of liquid metal coolants in nuclear power. Studies have been carried out to substantiate the technical and economic characteristics of nuclear fuel for operating, under construction and future NPPs of VVER RP, design solutions for passive safety, technical solutions and hydrogen safety devices, heat removal from the reactor through a steam generator and PHRS in case of beyond design basis accidents. As well as design solutions and safety for NPP designs with BN-1200 reactor with sodium coolant, BREST-OD-300 reactor with lead coolant, SVBR-100 reactor with lead-bismuth alloy, MBIR research reactor. The results of these studies made it possible, together with institutes and design organizations, to scientifically substantiate thermal-hydraulic parameters and highly efficient technological processes, develop and practically implement devices and systems that ensure the successful operation of fundamentally new nuclear power plants cooled by water and liquid metals, with original scientific and technical solutions that had no analogue in world practice. R&D works were carried out to substantiate the innovative project VVER with supercritical pressure, the concept of an electro-nuclear subcritical blanket based on the modular principle of constructing an core with liquid-salt melts of fissile materials, studies of thermal hydraulics, mass transfer of high-temperature sodium and the development of a combined coolant purification system to justify the BN-HT reactor with temperature sodium ~900 °C for hydrogen production. The directions of investigations at the present stage are discussed.

Recyclable, Healable, and Stretchable High‐Power Thermoelectric Generator

AbstractDirect energy conversion based on thermoelectric (TE) materials is a long‐term and maintenance‐free energy harvesting technique, and therefore is very promising for self‐powered wearable electronics. Yet, it is challenging to achieve high‐performance stretchable, healable, and even recyclable thermoelectric generators (TEGs) without compromising TE conversion performance due to the intrinsic mechanical rigidity and brittleness of the inorganic TE materials. Herein, recyclable, healable, and stretchable TEGs (RHS‐TEGs) are reported that are assembled from commercial Bi2Te3 and Sb2Te3 TE legs generating superior power density via the use of liquid metal as interconnects and dynamic covalent thermoset polyimine as encapsulation. The TEGs fabricated using this strategy are endowed with excellent TE performance, mechanical compliance, and healing and recycling capabilities. The normalized output power density and mechanical stretchability can reach up to 1.08 µW cm−2·K2 and 50%, respectively. After healing and recycling, the TEGs show output performance comparable to the original devices. The TEGs also exhibit high reliability and stability under cyclic deformation. This study paves the way for sustainable application of TEGs as energy harvesters to power wearable electronics using body heat.

Recent Advances in Deformable Circuit Components with Liquid Metal

AbstractDeformable electronics, specifically those incorporating liquid metal, allow for previously inaccessible mechanical behavior and exciting new technologies. This is demonstrated by recent, promising advances in the fabrication, characterization, device performance, and applications of liquid metal electronics. Through the use of liquid metals and soft, stretchable materials, it is shown that devices that provide stretchability and improved safety and comfort between humans and machines can achieve comparable or better electrical performance than conventional alternatives. Many of the latest major advances in liquid metal electronics focus on fundamental, deformable, passive circuit components and materials including capacitors, inductors, resistors, electrodes, wires, and composite materials, such as advances in biomimicry and deformation‐based sensing using both capacitors and inductors. Liquid metal passive components and materials have led to further progress in deformable secondary devices and applications such as antennas, actuators, power sources, and thermal management devices, including mechanical tuning for antennas, self‐sensing actuators, and power sources operational under stress. While deformable liquid metal electronics are still faced with challenges, the continued expansion of the field of liquid metal circuits is dramatically altering the research landscape of reconfigurable, self‐healable, and magnetically controllable electronics and revolutionalizing the way that electronics will be used in the future.