Nuclear Fusion Reactions Research Articles

Assessment of Nuclear Fusion Reaction Spontaneity via Engineering Thermodynamics.

This work recalls the basic thermodynamics of chemical processes for introducing the evaluation of the nuclear reactions' spontaneity. The application and definition of the thermodynamic state functions of the nuclear processes have been described by focusing on their contribution to the chemical potential. The variation of the nuclear binding potentials involved in a nuclear reaction affects the chemical potential through a modification of the internal energy and of the other state functions. These energy changes are related to the mass defect between reactants and products of the nuclear reaction and are of the order of magnitude of 1 MeV per particle, about six orders of magnitude larger than those of the chemical reactions. In particular, this work assesses the Gibbs free energy change of the fusion reactions by assuming the Qvalue as the nuclear contribution to the chemical potential and by calculating the entropy through the Sackur-Tetrode expression. Then, the role of the entropy in fusion processes was re-examined by demonstrating the previous spontaneity analyses, which assume a perfect gas of DT atoms in the initial state of the fusion reactions, are conservative and lead to assessing more negative ΔG than in the real case (ionized gas). As a final point, this paper examines the thermodynamic spontaneity of exothermic processes with a negative change of entropy and discusses the different thermodynamic spontaneity exhibited by the DT fusion processes when conducted in a controlled or uncontrolled way.

The unscientific history of cold fusion

Abstract The announcement in March 1989 that sustained nuclear fusion reactions had been achieved in a table-top apparatus generated much publicity. The claims proved to be unfounded. How the evidence for these claims was presented provides a case study on unscientific methods and the breaching of scientific conventions. It will be shown how respect for these conventions is important to avoid similar fiascos.

Manifestation of relativistic effects in the chemical properties of nihonium and moscovium revealed by gas chromatography studies.

Chemical reactivity of the superheavy elements nihonium (Nh, element 113) and moscovium (Mc, element 115) has been studied by the gas-solid chromatography method using a new combined chromatography and detection setup. The Mc isotope, 288Mc, was produced in the nuclear fusion reaction of 48Ca ions with 243Am targets at the GSI Helmholtzzentrum Darmstadt, Germany. After isolating 288Mc ions in the gas-filled separator TASCA, adsorption of 288Mc and its decay product 284Nh on silicon oxide and gold surfaces was investigated. As a result of this work, the values of the adsorption enthalpy of Nh and Mc on the silicon oxide surface were determined for the first time, kJ/mol and kJ/mol (68% c.i.). The obtained -ΔH ads values are in good agreement with results of advanced relativistic calculations. Both elements, Nh and Mc, were shown to interact more weakly with the silicon oxide surface than their lighter homologues Tl and Bi, respectively. However, Nh and Mc turned out to be more reactive than the neighbouring closed-shell and quasi-closed-shell elements copernicium (Cn, element 112) and flerovium (Fl, element 114), respectively. The established trend is explained by the influence of strong relativistic effects on the valence atomic orbitals of these elements.

Development of a Miniaturized 2-Joule Pulsed Plasma Source Based on Plasma Focus Technology: Applications in Extreme Condition Materials and Nanosatellite Orientation.

Plasma focus devices represent a class of hot and dense plasma sources that serve a dual role in fundamental plasma research and practical applications. These devices allow the observation of various phenomena, including the z-pinch effect, nuclear fusion reactions, plasma filaments, bursts, shocks, jets, X-rays, neutron pulses, ions, and electron beams. In recent years, considerable efforts have been directed toward miniaturizing plasma focus devices, driven by the pursuit of both basic studies and technological advancements. In this paper, we present the design and construction of a compact, portable pulsed plasma source based on plasma focus technology, operating at the ~2-4 Joule energy range for versatile applications (PF-2J: 120 nF capacitance, 6-9 kV charging voltage, 40 nH inductance, 2.16-4.86 J stored energy, and 10-15 kA maximum current at short circuit). The components of the device, including capacitors, spark gaps, discharge chambers, and power supplies, are transportable within hand luggage. The electrical characteristics of the discharge were thoroughly characterized using voltage and current derivative monitoring techniques. A peak current of 15 kiloamperes was achieved within 110 nanoseconds in a short-circuit configuration at a 9 kV charging voltage. Plasma dynamics were captured through optical refractive diagnostics employing a pulsed Nd-YAG laser with a 170-picosecond pulse duration. Clear evidence of the z-pinch effect was observed during discharges in a deuterium atmosphere at 4 millibars and 6 kilovolts. The measured pinch length and radius were approximately 0.8 mm and less than 100 μm, respectively. Additionally, we explore the potential applications of this compact pulsed plasma source. These include its use as a plasma shock irradiation device for analyzing materials intended for the first wall of nuclear fusion reactors, its capability in material film deposition, and its utility as an educational tool in experimental plasma physics. We also show its potential as a pulsed plasma thruster for nanosatellites, showcasing the advantages of miniaturized plasma focus technology.

Integrated modeling of anisotropic neutron yields of classical and spherical tokamaks

Estimations of counting rates of neutron spectrometers in experiments on controlled fusion with magnetic confinement, as well as calculations of energy resolved flux densities of fusion neutrons from plasma to the walls of a reactor require spatial integration of the local, usually anisotropic function of the neutron source. The integrated modeling consists of three main stages. First, sources of fast particles in beam- or wave-heated plasma are calculated. The next stage deals with spatial, energetic, and angular velocity distributions of plasma ions. Finally, double differential rate coefficients of nuclear fusion reactions are computed. This article describes calculations of spatial distributions of nuclear fusion reaction rates in classical and spherical tokamaks and the anisotropy of the neutron yield and spectra. The results are based on analytical formulas for energetic and angular distributions of the local source of fusion products in plasma. Examples of energetic spectral densities of neutron fluxes on first walls are presented, as well as energy resolved counting rates of collimated neutron spectrometers for perpendicular and tangential lines of sight.

Reduction of the deceleration phase to mitigate the negative effect of hydrodynamic instabilities in direct-drive ICF implosions

In the deceleration phase of an Inertial Confinement Fusion capsule implosion Rayleigh–Taylor hydrodynamic instability can affect or even quench the ignition and thermonuclear burn wave propagation. This instability tends to mix the inner hot plasma with the cold and dense plasma shell providing a mixing layer where nuclear fusion reactions are inhibited. The 1D hydrodynamics code Multi-IFE has been used to simulate the implosion of a direct-drive high-gain laser-capsule design and the temporal evolution of the average radius and thickness of the mixing layer have been estimated. To mimic the effect of the reduced reaction rate, the fuel reactivity in the mixing layer is artificially set to zero thus inhibiting the burn wave propagation throughout it nullifying the energy gain. In order to overcome this negative effect, secondary short and powerful laser pulse is added, shortening this way the deceleration phase, which in turn reduces the thickness of the mixing layer. A study has been carried out to identify the optimal secondary laser pulse that recovers the high energy gain.

Stepwise tuning carbon slits at sub-angstrom scale for dynamical separation of hydrogen isotope

Heavier hydrogen isotope is indispensable for many applications such as isotope tracing and labeling, neutron scattering, and nuclear fusion reaction. Thus it calls for efficient hydrogen isotope separation. Cryogenic adsorptive separation is an energy-efficient way for deuterium/protium (D2/H2) separation, requiring nanopores with precisely tuned pore size and suitable geometry to induce the quantum sieving effect. Herein, we report on the stepwise tuned slit-shaped ultramicropores at sub-angstrom (Å) scale for highly efficient D2/H2 separation. The opening width of carbon nanoslits was precisely tuned by the devised thermal-induced molecularly imprinting method. The adsorbent with 4.0 Å centered nanoslits showed an excellent D2/H2 uptake ratio of 1.9 with a high D2 uptake of 10.1mmol/g at 40 K and 100 kPa. Column breakthrough experiments revealed a high D2/H2 selectivity of 10.1 at 40 K. It evidenced that the 4.0 Å centered slits enable an optimal balance between the barrier induced by zero-point energy and the adsorption potential at 40 K, thereby reaching a selectively quantized configurational diffusion of D2/H2. Programmed thermal desorption experiments indicated that a 0.1 Å alteration of the slit size enhanced the quantum sieving effect of D2/H2 by 180 %. These results would benefit the understanding of D2/H2 separation behavior, and the design principle may inspire other isotope separations.

Ammonia borane-based targets for new developments in laser-driven proton boron fusion

Nuclear fusion reactions involving protons and boron-11 nuclei are sparking increasing interest thanks to advancements in high-intensity, short-pulse laser technology. This type of reaction holds potential for a wide array of applications, from controlled nuclear fusion to radiobiology and cancer therapy. In line with this motivation, solid ammonia borane samples were developed as target material for proton-boron (pB) nuclear fusion. Following synthesis and shaping, these samples were tested for the first time in a laser-plasma pB fusion experiment. An investigation campaign focusing on surface chemical/physical analysis was carried out to characterize such samples in terms of composition of B and H, precursors of the pB fusion nuclear reaction, thus having a key impact on the yield of the generated nuclear products, i.e., alpha particles. A follow-up experiment used an 8 J, 800 fs laser pulse with an intensity of 2 × 1019 W cm−2 to irradiate the targets, generating ∼ 108 alpha particles per steradian. The alpha particle energy range (2–6 MeV) and normalized yield per laser energy of up to (6 × 107 J/sr) are comparable with the best previous alpha particle yields found in literature. These results pave the way for a yet unexplored category of pB fusion targets.

Nuclear fusion and nuclear fusion materials

This paper introduces the basic principle of nuclear fusion and the development status of tokamak device, which leads to the core of this paper-nuclear fusion materials. The reason why this paper studies nuclear fusion materials is that up to now, nuclear fusion materials are one of the key difficulties in realizing controlled nuclear fusion. In this paper, the introduction of nuclear fusion materials is mainly the classification of nuclear fusion materials, such as structural materials, first wall materials, etc., and the main materials used in various parts at present. After that, the reasons why nuclear fusion materials are difficult to realize are also introduced. For example, at the point of temperature, the temperature of plasma during nuclear fusion reaction can reach tens of millions of degrees Celsius, while the melting point of tungsten, the known material with the highest melting point, is only over 3,000 degrees Celsius. In addition, the first wall material of nuclear fusion needs high energy resistance.

Extended X-ray absorption spectroscopy using an ultrashort pulse laboratory-scale laser-plasma accelerator

Laser-driven compact particle accelerators can provide ultrashort pulses of broadband X-rays, well suited for undertaking X-ray absorption spectroscopy measurements on a femtosecond timescale. Here the Extended X-ray Absorption Fine Structure (EXAFS) features of the K-edge of a copper sample have been observed over a 250 eV window in a single shot using a laser wakefield accelerator, providing information on both the electronic and ionic structure simultaneously. This capability will allow the investigation of ultrafast processes, and in particular, probing high-energy-density matter and physics far-from-equilibrium where the sample refresh rate is slow and shot number is limited. For example, states that replicate the tremendous pressures and temperatures of planetary bodies or the conditions inside nuclear fusion reactions. Using high-power lasers to pump these samples also has the advantage of being inherently synchronised to the laser-driven X-ray probe. A perspective on the additional strengths of a laboratory-based ultrafast X-ray absorption source is presented.

Exploratory neutronic evaluation on the enhancement of tritium breeding and energy multiplication capability using (Th,U)O2 in a solid-state tritium breeding blanket of a fusion demonstration reactor

The achievable tritium breeding ratio (TBR) in Korean fusion demonstration reactor (K-DEMO) that utilizing the deuterium-tritium nuclear fusion reaction for energy production is the critical design parameter for the self-sufficiency of tritium. However, the calculation uncertainty of the achievable TBR makes it difficult to fully understand the tritium fuel cycle in the K-DEMO. Moreover, if the achievable TBR is less than the required TBR, the calculation uncertainty of the achievable TBR makes the design limitation on the self-sufficient tritium supply of the K-DEMO. Therefore, making the achievable TBR larger than the required TBR is the most important goal of the K-DEMO design for the self-sufficient tritium supply. To create an achievable TBR with a margin greater than the required TBR, the modified neutron-multiplying material that is different from the typical neutron-multiplying material (9Be) is tested in this study. The blending of the fissionable (232Th) and fissile (233U) material with 9Be is attempted to enhance the neutron multiplication reaction resulting in a gradual increase of the achievable TBR according to the increase of the atomic faction of fissile material. With the addition of fissile material, it is found that energy multiplication accompanied by fission reaction is dramatic. The possibility of the self-breeding of 233U from 232Th is also justified. However, the neutronic damages resulting in the frequent replacement of the components in the tritium breeding blanket and generation of the high-level waste also occurred as the negative impact accompanied by the blending of 232Th and 233U with 9Be.

Discovering tungsten-based composites as plasma facing materials for future high-duty cycle nuclear fusion reactors

Despite of excellent thermal properties and high sputtering resistance, pure tungsten cannot fully satisfy the requirements for plasma facing materials in future high-duty cycle nuclear fusion reactions due to the coupled extreme environments, including the high thermal loads, plasma exposure, and radiation damage. Here, we demonstrated that tungsten-based composite materials fabricated using spark-plasma sintering (SPS) present promising solutions to these challenges. Through the examination of two model systems, i.e., tungsten-zirconium composite for producing porous tungsten near the surface and dispersoid-strengthened tungsten, we discussed both the strengths and limitations of the SPS-fabricated materials. Our findings point towards the need for future studies aimed at optimizing the SPS process to achieve desired microstructures and effective control of oxygen impurities in the tungsten-based composite materials.

Competitive barrier and trapping effects of helium bubbles on hydrogen isotopes migration behavior in tungsten

In fusion reactors, plasma-facing materials will be exposed to low-energy and high-flux plasma of the hydrogen isotopes fuel, i.e., deuterium (D) and tritium (T), along with helium (He), the product of nuclear fusion reactions. He irradiation is likely to trigger the formation of He bubbles beneath the material surface, exerting complex effects on the migration patterns of hydrogen isotopes. In this work, molecular dynamics simulations were employed to investigate the influence of nano-sized He bubbles on the D migration behavior in tungsten (W) during the continuous implantation and diffusion processes, which is more consistent with the fusion environment for plasma-facing materials. It is found that the influence of He bubbles on D migration behavior can be classified into barrier and trapping effects. These effects show a competitive relationship at different processes. During the implantation process, the barrier effect takes precedence over the trapping effect, leading to the reduced D retention. Conversely, during the diffusion process, the trapping effect dominates over the barrier effect, resulting in increased D retention. Due to the surface of He bubbles serves as the trapping sites for hydrogen isotopes, augmenting the size and density of He bubbles notably enriches the strong trapping sites in W. When the location of He bubble is closer to the surface, a higher frequency of interaction events occurs between the implanted D atoms and He bubbles, consequently increasing D retention. Additionally, it was also found that the lattice distortion in pure W is more pronounced than that in He bubble-containing W at high temperatures due to the robust interaction between D and He, which diminishes collisions between D atoms and the W lattice. This study gives a valuable insight into the influence of He bubbles on hydrogen isotopes migration behavior in the fusion environment.

A New Approach to Nuclear Fusion Based on Muon Catalysis by Means of High-Energy Ball Lightning and an Accelerative Mechanism

A new method of realizing nuclear fusion reactions based on muon catalysis and the accelerative mechanism is proposed. High-energy ball lightning is periodically generated in a reactor chamber filled with deuterium gas and directed into a container containing liquid tritium. The entry of ball lightning into the tritium is accompanied by the generation of muons and mesomolecules due to a cascade process. Following the ball lightning, a high-energy plasma jet moves under the influence of traveling transverse electromagnetic waves. Deuterium ions and electrons of the jet, accelerated by intense transverse electromagnetic waves, interact with the tritium. Nuclear fusion reactions occur with the participation of muonic molecules at very low temperature. The developed method resolves all physical and technical problems that are inherent in existing traditional methods.

A novel boron-conjugated SRC inhibitor for Proton Boron Capture Therapy in glioblastoma treatment

The ability of protons to deliver the maximum dose at the tumor region can work synergistically with boron atoms to emit alpha particles, enhancing therapy effects with less damage to healthy tissue. Protons and boron nuclear fusion reaction is the principle for the so-called Proton Boron Capture Therapy, that can contribute to high therapy efficiency by using smaller flux than conventional proton therapy, especially for radioresistant brain tumors such as glioblastoma. Glioblastoma is the most infiltrating and aggressive tumor of the brain with a very low life expectancy, ranging from 6 to 24 months. In this study we evaluated the protons combined effectwithanovelboron-conjugated compound, which is a pyrazolo[3,4-d]pyrimidine derivative, acting as SRC tyrosine kinase inhibitor. Indeed, this drug includes a boron cluster, that can be directed in tumor cells using the ATP-competitive mechanism of the pyrazolo[3,4 d]pyrimidine ring in activated SRC form of glioblastoma cells, achieving tumor uptake of boron for Proton Boron Capture Therapy reaction. This preliminary study showed interesting results that could offer important contributions for further experiments.

Catalytic Oxidation-like Nuclear Nano-fusion; Fractal Involving of Room Temperature Magnetically Induced μ-Catalyzed Fusion

The nuclear fusion reaction can be catalyzed in a suitable fusion fuel by muons (heavy electrons). “For the fractal relations, ranging from DNA knots to solar neutrino flux signals”, ever derived of scale-invariant properties distinguished between classical invariant theory & quantum invariant theory subfactors. Accompanying isomorphic & Connes FusionTensor Product retrieved to μ-catalyzed fusion where surroundings of room temperature fusion driven by the balance in mtDNA fusion & fission. On behalf of the nanometer dimension of the radius of heavy electrons & wavelength of UV-light, it assumed that muons can be produced by oxidation-like decay when UV-light impinging water.

Nuclear fusion introduction and artificial fusion status

Nuclear fusion, a process that has the potential to revolutionize the world's energy landscape, is the subject of extensive research due to its promise of providing a clean and safe energy source. The article outlines the essential principles of nuclear fusion and the chronology of its discovery, from early predictions to its initial realization in the first half of the 20th century. It also highlights the extreme requirements and challenges associated with fusion. Furthermore, the article introduces two natural nuclear fusion reactions: thermonuclear fusion and pycnonuclear fusion. In the final section, the focus shifts to artificial nuclear fusion, discussing the progression from the uncontrollable hydrogen bomb to efforts toward controlled atomic fusion since the mid-20th century. The article emphasizes various nuclear fusion configurations (Tokamak, Stellarator, ICF, Magnetic mirrors, and z-pinch) that have been proposed globally, detailing their features, strengths, and weaknesses.

New Method for 18FDG generating using Geant4/ Gate7

Fluorine 18-deoxyglucose is often used in Positron Emission Tomography devices. Positron Emission Tomography imaging is one of the useful tool which is used for cancer detection and its management. Positron Emission Tomography growth is limited due to problems that depend on the production of Fluorine-18. Imaging results are strongly depending on the information of nuclear reaction cross section data. This study is presented to calculate different quantities such as stopping power, CSDA range, simulated and distributed absorbed dose of Fluorine-18 in water. In order to access these goals, we use Geant4/Gate7 simulation and the Bethe-Bloch model. The results of this simulation and theoretical model presented are in good agreement with each other. The important point of this paper is the presentation of a theoretical approach in order to the production of Fluorine-18 using protons generated through the main D(d;p)Tand side 3 He(d;p)4 He nuclear fusion reaction in which uses Helium-3 is catalyzed.

Discussion on the development of nuclear energy and nuclear power plants

Nuclear energy is an extremely important source of energy. Nuclear energy always is considered a kind of clean energy, which has given it a lot of chances to develop. Nevertheless, the potential hazards associated with nuclear energy as well as concerns regarding resource depletion and environmental impact often result in strong opposition. Therefore, the future direction of nuclear power plants is particularly important. This paper aims to discuss the current state and prospects of nuclear energy development. While nuclear energy is experiencing rapid growth, it also faces various challenges simultaneously. These previous advancements serve as crucial foundations for future progress in nuclear energy. Therefore, this passage highlights the pivotal developments in the history of nuclear power plants, encompassing both fission and fusion reactions at their physical core. Additionally, it addresses the issues currently encountered by nuclear plants and proposes potential solutions to these concerns. Furthermore, it acknowledges that public perception plays a significant role in shaping the trajectory of nuclear energy development. Lastly, it introduces novel technologies and strategies that have the potential to enhance the future of nuclear energy. By analyzing emerging fusion-based nuclear energy approaches, we can discern valuable insights into the future direction of our existing nuclear technology landscape. Consequently, comprehending contemporary developments and challenges within the realm of nuclear energy enables us to better evaluate its role and impact within our future energy framework.

Improving thermal conductivity of reduced-activation ferritic/martensitic steel using three-dimensional woven copper fiber

Reduced-activation ferritic/martensitic (RAFM) steel is a primary candidate for blanket modules in nuclear-fusion reactors. Blanket modules transfer thermal energy generated by nuclear-fusion reactions to the coolant; therefore, blanket materials must have high thermal conductivity. RAFM steel is suitable for fusion reactors owing to its high strength, toughness, and resistance to neutron irradiation; however, its thermal conductivity is lower than that of other metals. This study fabricates RAFM steel–copper composites using three-dimensional (3D) woven copper fibers with different volume fractions as a preform to improve the thermal conductivity of RAFM steel around the coolant pipes. The microstructural, mechanical, and thermal properties of the developed composites and the correlations between them are experimentally investigated. Finite element simulations were also conducted on the composites comprising 3D woven copper fibers to evaluate the effective thermal conductivity. The factors that improve the effective thermal conductivity of RAFM steel–copper composites are discussed through a comparison with copper-powder composites with comparable volumes. This study demonstrates the manufacturing of composites with excellent thermal and mechanical properties using various 3D woven structures as preforms.