Deuterium Fusion Research Articles

Research on ion cyclotron emission driven by deuterium–deuterium fusion-produced tritium ions on the Experimental Advanced Superconducting Tokamak

Abstract In the 2023 experiment campaign, we measured ion cyclotron emission (ICE) signals on the Experimental Advanced Superconducting Tokamak (EAST), edge ICE excited by tritium ions. A fusion product derived from the deuterium–deuterium (D–D) fusion reaction, whose spectral peak matches the fundamental cyclotron frequency of the tritium ions (ωCT) in the plasma edge near the last closed flux surface, was observed using the ion cyclotron range of frequency (ICRF) antenna-based diagnostic system at the plasma boundary on the low field side in the EAST. In this study, we present the first observation of ICE with frequency matching at the plasma boundary. The excitation position of ICE is approximately R = 2.29 m on EAST, and we find that ICE is easier to excite below a certain threshold of plasma radiation. To investigate the excitation mechanism of ICE, we obtained the tritium ion distribution via the TRANSP/Fusion Products Model code and used it to explain the excitation mechanism of ICE. The given distribution has a bump-on tail structure in the energy direction and anisotropy in the pitch angle direction. In addition, we explain why high-energy tritium ions can reach and accumulate at the plasma boundary. It is important to study ICE because ICE can help distinguish the species of fusion-product ions, which can also help monitor the fusion alpha ions in large fusion devices, such as CFETR, DEMO, and ITER.

Potential Technosignature from Anomalously Low Deuterium/Hydrogen in Planetary Water Depleted by Nuclear Fusion Technology

Abstract Deuterium–deuterium (DD) fusion is viewed as an ideal energy source for humanity in the far future, given a vast seawater supply of D. Here, we consider long-lived, extraterrestrial, technological societies that develop DD fusion. If such a society persisted over geologic timescales, oceanic deuterium would diminish. For an ocean mass and initial deuterium/hydrogen (D/H) ratio that were Earth-like, fusion power use of only ∼10 times that projected for humankind next century would deplete the D/H ratio in ∼(a few) ×108 yr to values below that of the local interstellar medium (ISM). Ocean masses of a few percent of Earth’s would reach an anomalously low D/H in ∼106–107 yr. The timescale shortens with greater energy consumption, smaller oceans, or lower initial D/H. Here, we suggest that anomalous D/H in planetary water below local ISM values of ∼16 × 10−6 (set by Big Bang nucleosynthesis plus deuterium loss onto dust or small admixtures of deuterium-poor stellar material) may be a technosignature. Unlike SETI using radio signals, anomalous D/H would persist for eons, even if civilizations perished or relocated. We discuss the wavelengths of strong absorption features for detecting D/H anomalies in atmospheric water vapor. These are vibrational O–D stretching at 3.7 μm in transmission spectroscopy of Earth-like worlds, ∼1.5 μm (in the wings of the 1.4 μm water band) in the shorter near-infrared for direct imaging by the Habitable Worlds Observatory, and ∼7.5-8 μm (in the wings of the broad 6.3 μm bending vibration of water) for concepts like the Large Interferometer for Exoplanets.

Deep Eutectic Solvents as Candidates for Lithium Isotope Enrichment

Nuclear fusion is a phenomenon that is well known within the nuclear physics community as a viable option for alternative energy as many natural gases and fossil fuels are phased out of commercial use. Deuterium and tritium fusion reactions are currently the leading candidates for nuclear fusion, with a major limiting factor being a means to produce tritium on an industrial scale. Lithium-6 is a well-known isotope that can produce tritium and helium following a fission reaction with a neutron. Unfortunately, the lithium-6 enrichment methods are limited to the COLEX process, which leaves behind an alarming amount of mercury waste as a potential environmental contaminant. Deep eutectic solvents are believed to be a potential alternative to lithium isotope separations due to the ease of generation, in addition to the minimum environmental waste generated when these solvents are employed. Previous studies have suggested that deep eutectic solvents are capable of separating lithium isotopes by utilizing a 2-thenoyltrifluoroacetone and trioctylphosphine oxide system that can biphasically react with a buffered solution containing lithium chloride. This system displays a separation factor of 1.068, which when compared to the 1.054 separation within the COLEX process, makes it a potential candidate for lithium-6/7 separation. Within this study, we investigate this system in comparison to two newly synthesized deep eutectic solvents and find that within these acetylacetone-based systems, little isotopic separation is observed. We investigate these systems both experimentally and computationally, showing the different lithium cation affinities, in addition to proposing how the electron-donating or -withdrawing nature can influence these systems.

Stable Deuterium-Tritium plasmas with improved confinement in the presence of energetic-ion instabilities

Providing stable and clean energy sources is a necessity for the increasing demands of humanity. Energy produced by Deuterium (D) and Tritium (T) fusion reactions, in particular in tokamaks, is a promising path towards that goal. However, there is little experience with plasmas formed by D-T mixtures, since most of the experiments are currently performed in pure D. After more than 20 years, the Joint European Torus (JET) has carried out new D-T experiments with the aim of exploring some of the unique characteristics expected in future fusion reactors, such as the presence of highly energetic ions in low plasma rotation conditions. A new stable, high confinement and impurity-free D-T regime, with reduction of energy losses with respect to D, has been found. Multiscale physics mechanisms critically determine the thermal confinement. These crucial achievements importantly contribute to the establishment of fusion energy generation as an alternative to fossil fuels.

Investigation of the Effects of Ion Sources and RF Power on the Neutron Production Rate at SNRTC-IEC Fusion Device

Studies on an inertial electrostatic confinement (IEC) device are generally focused on increasing particle production. One way to achieve this is to increase the number of ion sources. In this study, the deuterium-deuterium fusion reaction was carried out in the IEC Saraykoy Nuclear Research and Training Center (SNRTC-IEC) fusion device (previously at the Turkish Atomic Energy Authority, now reestablished as the Turkish Energy, Nuclear and Mineral Research Agency) at cathode voltage of 85 kV and pressure of 5 × 10−4 mbars, and the effect of ion sources and radio-frequency (RF) power on the neutron production rate was investigated. To ensure a high concentration of ions in the center of the cathode, three inductively coupled plasma deuterium ion sources were added to this device. As the number of ion sources increased from one to three, the neutron production rate increased from 2.3 × 104 to 3.6 × 105n/s. Two ion source configurations were used to examine the effect of RF power. It was observed that when the RF power was increased from 40 to 200 W, the neutron production rate increased linearly from 4.6 × 104 to 1.7 × 105 n/s.

Proton beams generated via thermonuclear deuterium–deuterium fusion by means of modified cavity pressure acceleration-type targets as a candidate for proton–boron fusion driver

In this Letter, we report the possibility of generating intense, highly energetic proton beams using terawatt, sub-nanosecond class laser system by irradiating modified cavity pressure acceleration-type targets. In this approach, the main source of few-mega electron volt protons is thermonuclear deuterium–deuterium reaction; therefore, the energy spectrum of accelerated particles and their number is not as strongly related to the laser intensity (laser pulse energy and pulse duration in particular) as in the case of the most common ion acceleration mechanism, namely, target normal sheath acceleration. Performed Monte Carlo simulations suggest that using mentioned mechanism to generate proton beam might be beneficial and efficient driver for laser induced proton–boron fusion when moderate-to-low laser pulse intensities ( ⩽ 1016W/cm2) and thin, lower than 100 μm boron foils are used as catchers.

Cathode cooling effects on the neutron production rate in the glow discharge type of fusion neutron source

Fusion reactions on the cathode surface of glow discharge deuterium–deuterium fusion neutron sources contribute significantly to the neutron production rate (NPR). While the NPR shows a linear relationship with current in the low current regime, a rise in cathode temperature in the high-current regime causes stagnation of the NPR. This tendency may be caused by high-temperature-induced desorption of deuterium on the cathode. This study aims to clarify the relationship between NPR and deuterium desorption. The present study utilized a water-cooling system to prevent deuterium desorption on the cathode. A stainless-steel 304 cathode and a diamond-like carbon (DLC)-coated cathode were tested. The cooling system kept the cathode temperature below 315 K throughout the experiment. In the case of the DLC-coated cathode, the water-cooling system improves the NPR in a high-current regime (30 mA or more in the present study). At 50 kV and 60 mA, the NPRs were 1.87 × 106 and 8.39 × 105 (n/s), with and without water cooling, respectively. Furthermore, without the cooling system, the NPR correlation with the cathode temperature indicates good agreement with the estimation model of deuterium desorption on the DLC-coated cathode. This study demonstrates that suppression of deuterium desorption in the cathode improves NPR, especially in the high-current regime.

Development of diamond detector as fast neutron spectroscopy in the EAST tokamak

We report in this paper the development of the single crystal diamond detector as a fast neutron spectroscopy in the EAST tokamak. The diamond detector is used to detect the fast neutron directly without any neutron converter during the deuterium-deuterium fusion experiment, then the neutron energy spectrum is reconstructed from the recorded continuous scattered spectrum by using a deconvolution algorithm. The results indicate the capability of the diamond spectroscopy which can be used directly to monitor the fast neutron flux and energy spectrum in the EAST tokamak.

OPTEMIST: A neutral beam for measuring quasi-omnigenity in Wendelstein 7-X

A new neutral beamline (OPTEMIST) uniquely capable of exploring the predicted improvement of fast ion confinement in Wendelstein 7-X (W7-X), which comes with increasing plasma beta, is proposed. As the plasma beta increases in the W7-X device, the high mirror magnetic configuration has drift orbits that begin to close, enhancing the confinement of the deeply trapped particles. The existing neutral beam system is found to produce particle populations that do not adequately probe the deeply trapped orbits. Fast tritons generated by thermal deuterium–deuterium fusion reactions are found to probe the necessary conditions for demonstrating this effect. However, it is found that diagnostically measuring this effect will be difficult. A scoping study of a neutral beamline that directly populates the trapped orbits is performed. It is found that a monoenergetic population of 120 kV injected protons provides the largest confinement enhancement in the fast ion population as the plasma beta is increased. The necessity to raise plasma density to increase plasma beta results in blinding of spectroscopic beam measurements by bremsstrahlung. An array of novel fast ion loss detectors that would adequately assess the confinement of these particles is proposed.

Introduction to Special Issue on the Early History of Nuclear Fusion

This introductory paper to the special issue of Fusion Science and Technology commemorates early research on fusion conducted at Los Alamos (the singular entity denoted Los Alamos Laboratory/Los Alamos Scientific Laboratory/Los Alamos National Laboratory at different times is designated “Los Alamos” in this paper) in support of the eventual H-bomb program. We survey the historical origins of the thermonuclear program, what was known of fusion reactions at the outbreak of the war, and the remarkable breakthroughs involving particularly the prospect of deuterium-tritium (DT) reactions conducted during the war, and we summarize the papers in this volume. Much of the nuclear fusion technical history presented herein has not been previously reported. Papers describe aspects of fusion science during these days, on shock hydrodynamics and on electron-radiation coupling, and on nuclear physics including the discoveries of resonances in both the DT cross section and in the lithium tritium-breeding cross section. Three papers follow our colleague Mark Paris’s finding Arthur Ruhlig’s 1938 paper on the first observation of DT fusion: one on how it influenced subsequent Manhattan Project research, another on a modern calculation of that historic experiment, and a third that has repeated the experiment using modern experimental capabilities. Other papers discuss how the first H-bomb test, Ivy Mike, led to the discovery of the new elements einsteinium and fermium and how the DT fusion processes played a key role in our universe’s development after the Big Bang. We also present a paper that analyzes the pioneering Cambridge University 1934 experiment by Marcus Oliphant, Paul Harteck, and Ernest Rutherford where deuterium-deuterium fusion was first observed and that describes how Ernest Lawrence missed identifying fusion in 1933. Finally, we present a summary of early concepts for controlled fusion energy that grew out of wartime discussions at Los Alamos. The papers show how J. Robert Oppenheimer played a leading technical role in the early developments of the H-bomb, before his later opposition—our first paper in this issue addresses the U.S. Department of Energy’s 2022 vacating of the earlier 1954 decision to revoke his security clearance.

Nuclear fusion as unlimited power source for ships

Every now and then, every marine engineer dreams of a compact, lightweight and inexhaustible energy source to power large ships across the seven seas. Nuclear fusion of deuterium and tritium promises to be a safe, compact, carbon-free, and inexhaustible energy source. Even though it will take decades before conventional power plants may be replaced with nuclear fusion, the concept of nuclear fusion for marine propulsion has already been put on the table by commercial parties. This research investigates the potential of nuclear fusion onboard ships. The design investigates putting the smallest imaginable magnetic confinement reactor, ARC, on a ship. The only commercial ship requiring significant amounts of power is the Queen Mary 2. The large power output of ARC (200 MWe) is one of the major issues of putting a fusion reactor on a ship. Other issues may include intact stability, structural design and influences of vibrations on the fusion reactor. All in all, we found that a fusion reactor onboard a ship is unlikely to be feasible in the near future.

Investigation of Cs27LiYCl6:Ce scintillator energy response for D-D fusion neutron spectrometer

During plasma experiments on EAST (Experimental Advanced Superconducting Tokamak), the discharges heated with neutral beam injection (NBI) for plasma results in the production of 2.45 MeV deuterium-deuterium (D-D) fusion neutrons. In order to measure the energy spectrum of D-D fusion neutrons, a new Cs27LiYCl6:Ce (CLYC-7) crystal with 7Li-enrichment has been developed and fabricated into a CLYC-7 scintillation detector. Before utilizing this detector for studying neutron energy spectra, it is crucial to explore the response function of the detector within a relevant neutron energy range. Therefore, the detector has been experimented using the 4.5 MeV electrostatic accelerator at Peking University to investigate its response to fast neutrons, energy resolution, and pulse discrimination capability in the neutron energy range 2.07 MeV–5.51 MeV. The neutron reactions occurring within the CLYC-7 scintillator were simulated using MCNPX, focusing on the reactions 35Cl(n,p) and 35Cl(n,α), as well as the energy response curve and the contributions of different particles (protons, alphas) to the neutron spectrum. The experimental results were successfully validated on EAST, where the 2.45 MeV fusion neutron energy spectrum was measured. That demonstrates the ability of the CLYC-7 scintillation detector to diagnose the fusion neutron energy spectrum for deuterium plasma discharge.

Energetic Ion Emission from TiDx in Low-Energy Ion Beam Experiments

Low-level energetic ion emission has been reported previously in many low-energy nuclear reactions (LENR) experiments including electrolysis, gas-loading and ion beam experiments. The corresponding reports present evidence for MeV-level charged ions and neutrons associated with deuterium-deuterium fusion reactions, and also particles at higher energy that would be expected to originate from other processes. A study of low-level energetic nuclear particles has the potential to shed light on nuclear processes relevant to excess heat production and other LENR anomalies, which provides motivation to focus on such observables. In some of the referenced earlier experiments a small number of very energetic charged particle emissions near 20 MeV have been reported, which is of particular interest to us in connection with the involved mechanisms. We developed an ion beam experiment in which thick (1.59 mm) and thin (5 μm) Ti foils were initially loaded with deuterium by ion beam implantation and then bombarded with argon ions at 950 eV. A small number of counts in high-energy detector channels were recorded in eight different experiments, corresponding to particle energies estimated to be between 32-40 MeV, based on a calibration at lower energies with an 241Am calibration source. Experiments with the 5 μm Ti foil also resulted in dozens of counts below about 11 MeV.

Mechanical design of ITER radial neutron camera Ex-Port system

The Radial Neutron Camera is an ITER diagnostic designed to measure the un-collided 14 MeV and 2.5 MeV neutrons from deuterium-tritium (DT) and deuterium-deuterium (DD) fusion reactions, through an array of detectors covering a poloidal plasma section along collimated Lines Of Sight (LOS). It is composed by two fan-shaped collimating structures viewing the plasma radially through vertical slots in the diagnostic shielding module of ITER Equatorial Port 1: the In-Port RNC, devoted to plasma edge coverage, and the Ex-Port RNC, devoted to the plasma core coverage. This paper presents an overview of the mechanical design of the Ex-Port RNC at the Preliminary Design Review (PDR) stage. The Ex-Port RNC is located in the Port Interspace and consists of a massive shielding structure hosting the detector units and two sets of collimators lying on different toroidal planes. The Ex-Port RNC design is presented both from the point of view of functional requirements (e.g. LOS positions and angles, radiation shielding, weight limitations) and of manufacturability. Finally, the Ex-port RNC structural integrity is assessed, and its design validated against the main loads and load combinations.

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.

Proposal of a Deuterium-Deuterium Fusion Reactor Intended for a Large Power Plant

Proposal of a Deuterium-Deuterium Fusion Reactor Intended for a Large Power Plant

Simulation of unfolding fast neutron spectrum from CR-39 track morphology

The aim of this study is to investigate the impact of various factors on neutron spectrum unfolding, including track parameters (major axis, minor axis and depth), polyethylene (PE) thickness, and etching time. The Monte Carlo code Geant4 and proton track parameter calculation program TRACK_P were applied to simulate the response matrix and track parameters spectrum. Four test spectra—252Cf spectrum, Gaussian broadened deuterium–deuterium fusion neutron spectrum, 241Am–Be spectrum, and Gaussian broadened deuterium–tritium fusion neutron spectrum—were studied using the maximum-likelihood expectation maximization algorithm for neutron spectrum unfolding. The unfolded spectra were in good agreement with the reference spectra. Results showed that the major and minor axes were more suitable than the track depth for neutron spectrum unfolding. For high-energy neutrons, a thick PE layer is required. Moreover, etching time does not significantly affect the unfolded spectra. This study explores the factors influencing the unfolding of fast neutron spectrum based on simulation calculations and preliminary experiments that can be useful for applying CR-39 to neutron spectrum measurements.

Electrode durability and sheared-flow-stabilized Z-pinch fusion energy

The sheared-flow-stabilized (SFS) Z-pinch concept is on a path to commercialization at Zap Energy. Recent experiments on the Fusion Z-pinch Experiment (FuZE) and newly commissioned FuZE-Q devices are advancing the state of the art in pinch current, stable plasma duration, and deuterium–deuterium fusion neutron production. The SFS Z-pinch configuration offers the promise of a compact fusion device owing to its simple geometry, unity beta, and absence of external magnetic field coils. In addition to a robust experimental program pushing plasma performance toward breakeven conditions, Zap Energy has parallel programs developing power handling systems suitable for future power plants. Technologies under development include high-repetition-rate pulsed power, high-duty-cycle electrodes, and liquid metal wall systems. The issue of electrode durability in future SFS Z-pinch power plants is elaborated on and compared with plasma material interaction regimes in other industrial processes and fusion energy systems.

Development of a High Sampling Rate Data Acquisition System Working in a High Pulse Count Rate Region for Radiation Diagnostics in Nuclear Fusion Plasma Research

In this study, a high sampling rate data acquisition system with the ability to provide timestamp, pulse shape information, and waveform simultaneously under a sub megahertz pulse counting rate was developed for radiation diagnostics for magnetic confinement nuclear fusion plasma research. The testing of the data acquisition system under the high pulse counting rate condition using real signals was performed in an accelerator-based deuterium-deuterium fusion neutron source (Fast Neutron Source) at the Japan Atomic Energy Agency. We found that the pulse counts acquired by the system linearly increased up to 6 × 105 cps, and the count loss at 106 cps was estimated to be ~10%. The data acquisition system was applied to deuterium-deuterium neutron profile diagnostics in the deuterium gas operation of a helical-type magnetic confinement plasma device, called the Large Helical Device, to observe the radial profile of neutron emissivity for the first time in a three-dimensional magnetic confinement fusion device. Time-resolved measurements of the deuterium-deuterium fusion emission profile were performed. The experimentally observed radial neutron emission profile was consistent with numerical predictions based on the orbit-following models using experimental data. The data acquisition system was shown to have the desired performance.

Gas composition change during operation of a compact discharge fusion neutron source with a closed deuterium supply system

A compact cylindrical fusion neutron source has been developed for various applications, such as a D–T fusion neutron source for blanket neutron transport experiments for blanket development. Currently, the operation of a discharged fusion device is mostly deuterium–deuterium (D–D) fusion, in which D2 fuel is continuously fed to the vacuum chamber and pumped out to keep its pressure constant. Deuterium–tritium (D–T) fusion operation requires a closed supply system for radioactive tritium. So, the fuel supply system has been developed using ZrCo. In this system, however, fuel D2 gas is diluted due to light hydrogen released from the inner wall of the vacuum chamber and the surface of the electrodes, which results in a decrease of neutron production rate (NPR). Therefore, the external gas supply mode was performed to remove light hydrogen from the electrode surface before the operation of the closing system. The results of the gas analysis show that H2 was not increased and the D2 ratio was maintained. As a result, the neutron production rate achieved (NPR) > 105 n/s, and the dependency of the NPR on the voltage was similar to that of the external supply mode. These results indicate that removing light hydrogen from the electrode surface is effective to suppress fuel gas dilution.