Controlled Fusion Reaction Research Articles

Bayesian batch optimization for molybdenum versus tungsten inertial confinement fusion double shell target design

AbstractAccess to reliable, clean energy sources is a major concern for national security. Much research is focused on the “grand challenge” of producing energy via controlled fusion reactions in a laboratory setting. For fusion experiments, specifically inertial confinement fusion (ICF), to produce sufficient energy, the fusion reactions in the ICF fuel need to become self‐sustaining and burn deuterium‐tritium (DT) fuel efficiently. The recent record‐breaking NIF ignition shot was able to achieve this goal as well as produce more energy than used to drive the experiment. This achievement brings self‐sustaining fusion‐based power systems closer than ever before, capable of providing humans with access to secure, renewable energy. In order to further progress toward the actualization of such power systems, more ICF experiments need to be conducted at large laser facilities such as the United States's National Ignition Facility (NIF) or France's Laser Mega‐Joule. The high cost per shot and limited number of shots that are possible per year make it prohibitive to perform large numbers of experiments. As such, experimental design relies heavily on complex predictive physics simulations for high‐fidelity “preshot” analysis. These multidimensional, multi‐physics, high‐fidelity simulations have to account for a variety of input parameters as well as modeling the extreme conditions (pressures and densities) present at ignition. Such simulations (especially in 3D) can become computationally prohibitive to turn around for each ICF experiment. In this work, we explore using Bayesian optimization with Gaussian processes (GPs) to find optimal designs for ICF double shell targets, while keeping computational costs to manageable levels. These double shell targets have an inner shell that grades from beryllium on the outer surface to the higher Z material molybdenum, as opposed to the nominally used tungsten, on the inside in order to trade off between the high performance associated with high density inner shells and capsule stability. We describe our results for “capsule‐only” xRAGE simulations to study the physics between different capsule designs, inner shell materials, and potential for future experiments.

Advancements in Portable Deuterium Reactor Systems: A Multifaceted Scientific Investigation

Deuterium, an isotope of hydrogen, holds significant promise across a spectrum of scientific and industrial domains, particularly within the realms of nuclear technology, chemistry, and pharmaceuticals. This comprehensive review explores the multifaceted applications and implications of deuterium utilization, spanning from its role in nuclear fusion reactors to its incorporation into organic molecules for medicinal purposes. In the field of nuclear fusion, deuterium serves as a primary fuel source, offering the potential for clean, sustainable energy production through controlled fusion reactions. Detailed experimental studies have revealed the efficacy of electrolysis-based methods for deuterium enrichment, leading to substantial increases in deuterium concentration within water and organic solvents. Moreover, novel approaches such as laser stimulation have been investigated to enhance the efficiency of deuterium extraction and fusion processes. Beyond nuclear fusion, deuterium finds extensive use in organic chemistry, where isotopic labeling techniques enable the synthesis of deuterated compounds with altered chemical and pharmacokinetic properties. This includes the production of deuterated polyunsaturated fatty acids (D-PUFAs), offering new avenues for drug development and metabolic research. Economically, the commercialization of deuterium-based technologies presents lucrative opportunities for industries involved in energy production, pharmaceuticals, and materials science. The increasing demand for deuterated compounds underscores the importance of efficient and sustainable methods for deuterium extraction and enrichment. Looking ahead, ongoing research endeavors aim to further optimize deuterium-related processes, enhance fusion reactor efficiency, and explore novel applications in fields such as isotope geochemistry and environmental remediation. However, challenges remain, including the scalability of deuterium production, regulatory hurdles, and geopolitical considerations surrounding deuterium-rich regions. In conclusion, the comprehensive examination of deuterium's diverse applications underscores its pivotal role in advancing scientific understanding and technological innovation. By harnessing its unique properties, researchers and industries alike stand poised to unlock new frontiers in energy, medicine, and beyond.

Dynamic phase microscopy reveals periodic oscillations of endoplasmic reticulum during network formation.

Dynamic phase microscopy was used to study the dynamic events of formation of the endoplasmic reticulum (ER) in interphase-arrested Xenopus egg extract. We have shown that the ER periodically oscillated in an ATP-dependent manner in the frequency range of 1.6-2.2 Hz, while the tubular membrane network formed in vitro. The spectral density, i.e. the pattern of a given frequency component in the Fourier spectrum, was strongly correlated with the dynamic events during microtubule-dependent and microtubule-independent ER network formation observed by video-enhanced contrast differential interference contrast and fluorescence microscopy. Because the 1.6-2.2 Hz frequency of oscillation during the network formation was detected both in the presence and absence of microtubules, it appears to be an intrinsic ATP-dependent ER membrane property. Several characteristic active and inactive stages of ER network formation were observed both in the presence and absence of microtubules. However, data analysis of these stages indicated that microtubules and dynein motor activity have a strong influence and a cooperative effect on the kinetics of ER formation by controlled fusion reaction.

Safety issues and approach to meet the safety requirements in the tokamak cooling water system of ITER

ITER (Latin for the “way”) is an experimental tokamak fusion energy reactor that is being built in Cadarache, France, in collaboration with seven agencies representing China, the European Union, India, Japan, South Korea, the Russian Federation, and the United States. The main objective of ITER is to demonstrate the scientific and technical feasibility of a controlled fusion reaction that will allow the production of approximately 500 MW of fusion power for durations of several hundred seconds. As an experimental facility, ITER is intended to allow the exploration of physics scenarios, to conduct the technological tests essential to the preparation of a fusion reactor, and to demonstrate the favorable safety characteristics of fusion. The ITER tokamak cooling water system (TCWS) consists of several separate systems to cool the major ITER components—the divertor/limiter, the first wall blanket, the vacuum vessel, and the neutral beam injector. The ex-vessel part of the TCWS provides a confinement function for tritium and activated corrosion products in the cooling water. The vacuum vessel system also has a functional safety requirement regarding the residual heat removal from in-vessel components. A preliminary hazards assessment (PHA) was performed for a better understanding of the hazards, initiating events, and defense-in-depth mechanisms associated with the TCWS. The PHA was completed using the following steps. (1) Hazard identification. Hazards associated with the TCWS were identified including radiological/chemical/electromagnetic hazards and physical hazards (e.g., high voltage, high pressure, high temperature, and falling objects). (2) Hazard categorization. Hazards identified in the first step were categorized as to their potential for harm to the workers, the public, and/or the environment. (3) Hazard evaluation. The design was examined to determine initiating events that might occur and that could expose the public, the environment, or workers to the hazard. In addition, the system was examined to identify barriers that prevent exposure. Finally, consequences to the public or workers were qualitatively assessed should the initiating event occur and one or more of the barriers fail. Frequency of occurrence of the initiating event and subsequent barrier failure was qualitatively estimated. (4) Accident analyses. A preliminary hazards analysis was performed on the conceptual design of the TCWS. As the design progresses, a detailed accident analysis will be performed in the form of a failure modes and effects analysis. The results of the PHA indicated that the principal hazards associated with the TCWS were those associated with radiation. These were low compared to hazards associated with nuclear fission reactors and were limited to potential exposure to the on-site workers if appropriate protective actions were not used. However, the risk to the general public off-site was found to be negligible even under worst case accident conditions.

Conceptual design of JT-60SA cryostat

This paper describes the conceptual design of cryostat for the JT-60SA, which is a research device for the commercial production of electricity from the controlled fusion reaction in the future. JT-60SA is designed to be a fully superconducting device and cryostat is one of the main components to allow the normal operation. Cryostat covers up the tokamak device, which is 15 m of total height and 7 m of radius, and supports the total weight of 25 MN. Cryostat components consist of vessel body, gravity support and auxiliary systems, such as 80 K thermal shield and vacuum exhaust. The functions required of cryostat are these three, thermal insulation for superconducting magnets, gravity support for the tokamak device, and bio-shielding. The design conditions for each cryostat component are outlined and the features of auxiliary systems such as capacity of vacuum exhaust related to 80 K thermal shield design are summarized.

Computations for nonlinear force driven plasma blocks by picosecond laser pulses for fusion

The concept of the fast ignitor for laser fusion has led to some modifications in applying petawatt-picosecond (PW-ps) laser-produced high intensity particle beams to ignite deuterium-tritium (DT) fuel. Some very anomalous measurements of ion emission from targets irradiated by picosecond laser pulses led to the development of a skin depth interaction scheme where a defined control of prepulses is necessary. Based on these experimental facts, we have applied a one-dimensional two-fluid hydrodynamic code to understand how the nonlinear ponderomotive force generates two plasma blocks, one moving against the laser light (ablation) and the other moving into the target. This compressed block produces an ion current density of above 10$^{11}$ A cm$^{-2}$ and an ion energy of about 100 keV. This may be a rather promising option to use PW-ps laser pulses for igniting fusion in solid density DT fuel, realizing very high gain controlled fusion reactions.

Developments in inertial fusion energy and beam fusion at magnetic confinement

The 70-year anniversary of the first nuclear fusion reaction of hydrogen isotopes by Oliphant, Harteck, and Rutherford is an opportunity to realize how beam fusion is the path for energy production, including both branches, the magnetic confinement fusion and the inertial fusion energy (IFE). It is intriguing that Oliphant's basic concept for igniting controlled fusion reactions by beams has made a comeback even for magnetic confinement plasma, after this beam fusion concept was revealed by the basically nonlinear processes of the well-known alternative of inertial confinement fusion using laser or particle beams. After reviewing the main streams of both directions some results are reported—as an example of possible alternatives—about how experiments with skin layer interaction and avoiding relativistic self-focusing of clean PW–ps laser pulses for IFE may possibly lead to a simplified fusion reactor scheme without the need for special compression of solid deuterium–tritium fuel.

Microcharacterization of Defects Induced in Fused Silica by High Power 3ω UV (355nm) Laser Pulses

Abstract There are many technical challenges to be overcome before controlled fusion reactions can be achieved. The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is being developed to initiate fusion reactions using the world's most powerful laser. Essential components of the Facility are the ultra pure silica (SiO2) lenses that focus the powerful laser beams on to the target. Irradiation with a high power laser has been observed to damage the silica lenses, resulting in the formation of defects. The ensuing degradation of the lens performance necessitates its replacement. It is therefore critical to characterize the induced defects and understand the laser damage initiation and evolution, so that damage mitigation strategies can be developed. Cathodoluminescence (CL) microscopy and spectroscopy enables high spatial resolution and high sensitivity detection of defects in poorly conducting materials. It is therefore an ideal microanalytical technique with which to study laser irradiation-induced defects.

In vitro formation of the endoplasmic reticulum occurs independently of microtubules by a controlled fusion reaction.

We have established an in vitro system for the formation of the endoplasmic reticulum (ER). Starting from small membrane vesicles prepared from Xenopus laevis eggs, an elaborate network of membrane tubules is formed in the presence of cytosol. In the absence of cytosol, the vesicles only fuse to form large spheres. Network formation requires a ubiquitous cytosolic protein and nucleoside triphosphates, is sensitive to N-ethylmaleimide and high cytosolic Ca(2+) concentrations, and proceeds via an intermediate stage in which vesicles appear to be clustered. Microtubules are not required for membrane tubule and network formation. Formation of the ER network shares significant similarities with formation of the nuclear envelope. Our results suggest that the ER network forms in a process in which cytosolic factors modify and regulate a basic reaction of membrane vesicle fusion.

Nuclear fusion without weapons testing

The US National Ignition Facility has one support from both nuclear weapon scientisis and advocates of fusion energy after developing the first device to ignite a controlled fusion reaction.

Cold fusion - a theoretical framework for cold fusion mechanism

Reprinted from the EPRI Journal, July/August 1989. Nuclear fusion would appear to be an ideal source of energy for many reasons. Fuel costs are likely to be low, since one of the potential fuels, deuterium, occurs in vast amounts in the oceans. In addition, there is relatively little radioactivity associated with fusion compared with nuclear fission as an energy source. Because of the large conversion of mass to energy, fusion can produce a million times more energy per atom than a chemical reaction. Much work has been done for over three decades on high-temperature, plasma-controlled fusion, but the achievement of sustained, controlled fusion reactions in high-temperature plasmas still seems remote.

Controlled Fusion Reactions

A plasma physics review is given for controlled fusion reactions. Also, devices used in fusion studies are described, i.e., dynamic and semi-static self- pinched plasma devices, magnetic compression devices, and ionic injection into a static magnetic bottle. (N.W.R.)

Optimum power generation from a moving plasma

The possibility exists of directly using the plasma, resulting from a controlled fusion reaction, to generate electricity by electromagnetic induction. Two special cases of a more general problem are considered here: (1)the extraction of optimum power from the steady one-dimensional flow of an incompressible inviscid plasma across a uniform transverse magnetic field in an externally loaded channel of arbitrarily varying cross-section, and (2) the extraction of optimum power from the steady one-dimensional flow of a compressible inviscid plasma across a uniform transverse magnetic field in a channel of uniform cross-section. In each case, the magnitude of the required external loading at optimum power operation is determined as a function of the parameters which characterize the hydromagnetic interaction. Also determined are the magnitudes of the terminal voltate, power, fluid mechanical to electrical conversion efficiency, and the variation of the fluid dynamical variables along the channel at optimum power.

Research on controlled fusion reactions

Research on controlled fusion reactions

Controlled Fusion Research-An Application of the Physics of High Temperature Plasmas

Some of the long-range implications and advantages of achieving the production of power from controlled fusion reactions between isotopes of hydrogen, helium, and lithium are set forth. The physical conditions which seemingly must be established to accomplish this are presented. These are shown to lead to a situation in which the fusion fuel will exist in the form of a very hot, tenuous, fully ionized gas-i.e., a plasma. It is shown that the required conditions can be maintained only by the use of a force field, for example, a magnetic field, to confine the plasma. A simple example of magnetic confinement-the pinch effect-is described. The electrodynamic properties of a fully ionized gas interacting with a magnetic field are briefly outlined. General scaling laws which would probably apply to any operable controlled fusion reactor are given. Examples are cited of fruitless approaches to the achievement of controlled fusion. Some aspects of the problem of "plasma diagnostics" are described to illustrate means for an experimental approach to high temperature plasma physics.

Controlled Fusion Research—An Application of the Physics of High Temperature Plasmas

Some of the long-range implications and advantages of achieving the production of power from controlled fusion reactions between isotopes of hydrogen, helium, and lithium are set forth. The physical conditions which seemingly must be established to accomplish this are presented. These are shown to lead to a situation in which the fusion fuel will exist in the form of a very hot, tenuous, fully ionized gas-i.e., a plasma. It is shown that the required conditions can be maintained only by the use of a force field, for example, a magnetic field, to confine the plasma. A simple example of magnetic confinement?the pinch effect?is described. The electrodynamic properties of a fully ionized gas interacting with a magnetic field are briefly outlined. General scaling laws which would probably apply to any operable controlled fusion reactor are given. Examples are cited of fruitless approaches to the achievement of controlled fusion. Some aspects of the problem of diagnostics are described to illustrate means for an experimental approach to high temperature plasma physics.