Deuterium Gas Research Articles

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.

Deuterium Stream Management Leaving the LPCE Column in a CECE Process for Heavy Water Detritiation

In heavy water detritiation using the combined electrolysis and catalytic exchange (CECE) process, deuterium leaving the electrolyzer is fed to the bottom of the liquid-phase catalytic exchange column (LPCE) in which tritium exchanges between the tritiated deuterium gas (moving upward in the LPCE column) and D2O liquid (moving downward in the LPCE column). Once the deuterium gas leaves the LPCE column, typically a trickle bed recombiner (TBR) is used to convert the incoming deuterium gas into the heavy water. In this study a different approach is presented in which instead of using a TBR, an additional LPCE column is used. In the additional LPCE column, deuterium gas is scrubbed with demineralized light water. This process alternative has many advantages over using a TBR. First, the oxidation of isotopic hydrogen is highly exothermic and requires a separate water-cooling circuit to maintain the temperature within the TBR. Second, a TBR requires a relatively complex internal design to ensure proper distribution of the gas, otherwise catalyst burnup may occur. Using a LPCE column instead of a TBR eliminates these complications. This paper presents a high-level layout of the process plant in which a LPCE column is used instead of a TBR. Column modeling and results are also presented.

Systematic design of a multi-input multi-output controller by model-based decoupling: a demonstration on TCV using multi-species gas injection

In this paper, we present the first results of a systematically designed multi-input multi-output gas-injection controller on Tokamak á Configuration Variable (TCV). We demonstrate the simultaneous real-time control of the NII emission front position and line-integrated electron density using nitrogen and deuterium gas injection. Injection of nitrogen and/or deuterium affects both the NII emission front position and line-integrated electron density. This interplay between control loops is termed interaction and, when strongly present, makes designing a controller a significantly more complex problem. Interaction between the control loops can be reduced to an acceptable level by redefining inputs, decoupling the multi-input multi-output control problem to separated single-input single-output problems. We demonstrate how to achieve this by defining virtual control inputs from linear combinations of the actuators available. For the demonstration on TCV, linear combinations of deuterium and nitrogen gas injection are computed from transfer-function models to obtain these virtual inputs. The virtual inputs reduce the interaction in the control-relevant frequency range to a point where control of the NII emission front position and line-integrated electron density can be considered decoupled, allowing for the much simpler design of single-input single-output controllers for each loop. Implementing the controllers with the virtual inputs gives the multi-input multi-output gas-injection controller. This approach is well established in the control community, and is presented here as a demonstration to drive developments of multi-input multi-output control strategies. In particular, the envisioned control of particle- and heat fluxes impacting the divertor targets by injection of multiple gas species.

Development of a new method for activation of isotope exchange

The in uence of various factors on the e ciency of introducing deuterium into3-(N-pyrrolyl)-propanoylL-histidine and 3-(N-salicyl)-propanoyl-L-histidine has been studied. Heavy water was used as a source of deuterium. It is shown that the content of deuterium atoms in the substance can be increased by pretreating the reaction mixture with deuterium gas. The new approach opens up additional possibilities both for obtaining highly puri ed preparations by introducing hydrogen isotopes into organic compounds, and theoretically for a deeper understanding of the participation in this process of activated deuterium or tritium particles solvated on the carrier and in the pool of the substance.

Operational and engineering experiences of gas injection to JET for TT and DT operational campaigns

Following the first deuterium–tritium experiment (DTE1) at UKAEA, modifications were investigated to the Joint European Torus’ (JET) gas introduction (GI) systems to increase the gas feed capabilities of the JET facility to better support future campaigns. The GI systems comprise the GI and gas distribution system in the Active Gas Handling System (AGHS), and neutral beam injection and the tritium injection modules on the torus. During DTE1 about 100 g of tritium was supplied from AGHS to JET users. During the second deuterium–tritium experiment (DTE2) and the tritium–tritium experiment (TT) just over 373 g and 630 g of tritium respectively was supplied to JET users for the campaigns. The tritium and deuterium gas supply systems of the fuel cycle can be underestimated as having fewer technical or scientific challenges based on the mechanical simplicity of equipment that they consist of. However, operational experience has shown these systems have the potential to bottleneck a campaign programme. This publication outlines the upgrade requirements foreseen, following DTE1, for operations in the DTE2 and TT campaigns, how these changes impacted the gas supply operations, and where limitations were encountered. The areas discussed include—challenges of upgrading and maintaining equipment designed for a short operating life; the impact of having differences between user requirements and gas supply capabilities; the logistics of gas supply involving multiple control room locations; communication routes between gas supply systems and teams; and safely controlling and tracking tritium gas movements. The latest JET tritium campaigns highlighted a number of challenges for future facilities looking to operate in both batch and continuous gas injection operational modes. The recommendations from this publication intend to provide a starting point for how to address these challenges and optimise gas supply in support of future fusion programmes. This work has been carried out within the framework of the contract for the operation of the JET Facilities and has received funding from the European Union’s Horizon 2020 research and innovation programme. The views and opinions expressed herein do not necessarily reflect those of the European Commission.

Development of a Novel Method for Activation of Isotope Exchange

The influence of various factors on the efficiency of introducing deuterium into 3-(N-pyrrolyl)-propanoyl-L-histidine and 3-(N-salicyl)-propanoyl-L-histidine was studied. Heavy water was used as a source of deuterium. It is shown that the content of deuterium atoms in the substance can be increased by pretreating the reaction mixture with deuterium gas. The new approach opens up additional possibilities both for obtaining high labeled pharmaceuticals by introducing hydrogen isotopes into organic compounds, and theoretically for a deeper understanding of the role in this process of activated deuterium or tritium particles solvated on the carrier and in the pool of matter.

In situ Generated Iridium Nanoparticles as Hydride Donors in Photoredox-Catalyzed Hydrogen Isotope Exchange Reactions with Deuterium and Tritium Gas.

We have studied the photoredox-catalyzed hydrogen isotope exchange (HIE) reaction with deuterium or tritium gas as isotope sources and in situ formed transition metal nanoparticles as hydrogen atom transfer pre-catalysts. By this means we have found synergistic reactivities applying two different HIE mechanisms, namely photoredox-catalyzed and CH-functionalization HIE leading to the synthesis of highly deuterated complex molecules. Finally, we adopted these findings successfully to tritium chemistry.

In situ Generated Iridium Nanoparticles as Hydride Donors in Photoredox‐Catalyzed Hydrogen Isotope Exchange Reactions with Deuterium and Tritium Gas

AbstractWe have studied the photoredox‐catalyzed hydrogen isotope exchange (HIE) reaction with deuterium or tritium gas as isotope sources and in situ formed transition metal nanoparticles as hydrogen atom transfer pre‐catalysts. By this means we have found synergistic reactivities applying two different HIE mechanisms, namely photoredox‐catalyzed and CH‐functionalization HIE leading to the synthesis of highly deuterated complex molecules. Finally, we adopted these findings successfully to tritium chemistry.

The effect of gas injection location on a lithium vapor box divertor in NSTX-U

The lithium vapor box divertor is a proposed divertor design that will minimize contamination of the upstream plasma in a fusion device, while also ensuring protection of the target. In this design lithium is evaporated near the target by high temperature lithium surfaces, dissipating the plasma heat flux. The lithium vapor box has been predicted via the fluid-kinetic code scrape off layer plasma simulator (SOLPS-ITER) to achieve low (/0.05) upstream concentrations of lithium and low target heat fluxes. Here we compare two choices of deuterium gas puff location using SOLPS-ITER, the private flux region (PFR) and the common flux region (CFR), and find significant differences in the contamination level required to reach an acceptable target heat flux (defined here as q10 MW m−2). Deuterium gas puffing from the PFR is seen to better reduce upstream lithium contamination. The difference in puffing location is seen to cause changes in the upstream flow of lithium ions. The PFR puff, having better access to the separatrix, can better reduce the upstream-directed flow of lithium near the separatrix which is the primary source of contamination due to a large thermal force in this region. Puffing from the CFR, partially due to inefficacy at reducing separatrix lithium flow, has higher lithium concentration within the plasma. Solutions that reduce the heat flux to below 10 MW m−2 have a range of lithium concentrations between /0.01–0.12 depending on puff intensity, location, evaporator temperature and recycling at the various plasma facing components. The efficacy of the puffs is tested for sensitivity to deuterium recycling coefficient at the target, evaporators, and main chamber walls. A CFR located puff is found to be more dependent on the recycling coefficients used than a PFR located puff. regardless of the set of recycling coefficients chosen, PFR puffing achieves lower lithium contamination than CFR puffing for a given heat flux.

SYNTHESIS OF DEUTERIUM-LABELED SALICYLCARNOSINE

The effect of temperature on the effectiveness of the introduction of deuterium into a new biologically active compound salicylcarnosine (SC) has been studied. Deuterium gas and heavy water were used as a source of deuterium. The synthesis of labeled SC by the solid-phase method at 190°C leads to the production of [D]SC with a yield of 53%, and a deuterium content of about 4.8 atoms per molecule. During isotope exchange with deuterated water, it was shown that after pretreatment of the catalyst at room temperature with deuterium gas, isotope exchange between SC protons and deuterated water occurs more efficiently. [D]SC is formed with a yield of 46% and contains about 7.3 deuterium atoms per molecule. During the preparative synthesis of labeled SC according to this technique at 190°C, the yield of [D]SC was 60–70%, with a deuterium content of about 6.2 atoms per molecule. A new technique for activating the inclusion of deuterium in peptides opens up additional opportunities for obtaining highly labelled drugs.

The Fate of Water in Hydrogen-Based Iron Oxide Reduction.

Gas-solid reactions are important for many redox processes that underpin the energy and sustainability transition. The specific case of hydrogen-based iron oxide reduction is the foundation to render the global steel industry fossil-free, an essential target as iron production is the largest single industrial emitter of carbon dioxide. This perception of gas-solid reactions has not only been limited by the availability of state-of-the-art techniques which can delve into the structure and chemistry of reacted solids, but one continues to miss an important reaction partner that defines the thermodynamics and kinetics of gas phase reactions: the gas molecules. In this investigation, cryogenic-atom probe tomography is used to study the quasi in situ evolution of iron oxide in the solid and gas phases of the direct reduction of iron oxide by deuterium gas at 700°C. So far several unknown atomic-scale characteristics are observed, including, D2 accumulation at the reaction interface; formation of a core (wüstite)-shell (iron) structure; inbound diffusion of D through the iron layer and partitioning of D among phases and defects; outbound diffusion of oxygen through the wüstite and/or through the iron to the next free available inner/outer surface; and the internal formation of heavy nano-water droplets at nano-pores.

Development of a portable pulsed fast ⩾106 neutron generator based on a flexible miniature plasma focus tube

A plasma focus device is a laboratory fusion device that is used to produce pulsed neutrons for a few tens of ns duration. A compact plasma focus tube (volume ≈ 130 cm3) has been developed, and this was connected to a newly developed capacitor bank using 24 coaxial cables, each 10 m long. The capacitor bank was of compact size and consisted of four energy storage capacitors (each 6 µF, 20 kV, size: 20 cm × 20 cm × 30 cm). The peak discharge current of the capacitor bank was estimated to be 176 kA with a rise time of around 3.6 µs at maximum 4.8 kJ operation energy. The average neutron yield was observed to be maximum (3.1 ± 1.0) × 106 neutrons/pulse with a pulse duration of 15–25 ns at an operating energy of 2.7 kJ (15 kV) and deuterium gas filling pressure of 4 mbar. Long coaxial cables allow only the plasma focus head (neutron source) to be moved as per need, making this a portable pulsed neutron source that is useful in many applications, including in extreme conditions, such as in borehole logging applications for oil and mineral mapping. This report describes the various components of this portable neutron generator together with its neutron emission characteristics.

Quantitative Determination of De Novo Fatty Acid Synthesis in Brown Adipose Tissue Using Deuterium Oxide.

Fatty acid synthesis is a complex and highly energy demanding metabolic pathway with important functional roles in the control of whole-body metabolic homeostasis and other physiological and pathological processes. Contrary to other key metabolic pathways, such as glucose disposal, fatty acid synthesis is not routinely functionally assessed, leading to incomplete interpretations of metabolic status. In addition, there is a lack of publicly available detailed protocols suitable for newcomers in the field. Here, we describe an inexpensive quantitative method utilizing deuterium oxide and gas chromatography mass spectrometry (GCMS) for the analysis of total fatty acid de novo synthesis in brown adipose tissue in vivo. This method measures the synthesis of the products of fatty acid synthase independently of a carbon source, and it is potentially useful for virtually any tissue, in any mouse model, and under any external perturbation. Details on the sample preparation for GCMS and downstream calculations are provided. We focus on the analysis of brown fat due to its high levels of de novo fatty acid synthesis and critical roles in maintaining metabolic homeostasis.

Hydrogen Isotope Exchange by Homogeneous Iridium Catalysis in Aqueous Buffers with Deuterium or Tritium gas.

We have studied the highly selective homogeneous iridium-catalyzed hydrogen isotope exchange (HIE) with deuterium or tritium gas as an isotope source in water and buffers. With an improved water-soluble Kerr-type catalyst, we have achieved first insights to apply HIE reactions in aqueous media with different pH media. DFT calculations gave consistent insights in the calculated energies of transition states and coordination complexes, further explaining the observed reactivity and guidance on the scope and limitations for HIE reactions in water. Finally, we adopted these findings successfully to tritium chemistry.

Hydrogen Isotope Exchange by Homogeneous Iridium Catalysis in Aqueous Buffers with Deuterium or Tritium Gas

AbstractWe have studied the highly selective homogeneous iridium‐catalyzed hydrogen isotope exchange (HIE) with deuterium or tritium gas as an isotope source in water and buffers. With an improved water‐soluble Kerr‐type catalyst, we have achieved the first insight into applying HIE reactions in aqueous media with varying pH. Density functional theory (DFT) calculations gave consistent insights in the calculated energies of transition states and coordination complexes, further explaining the observed reactivity and guidance on the scope and limitations for HIE reactions in water. Finally, we successfully adapted these findings to tritium chemistry.

Experimental results of deuterium/hydrogen co-current permeation through Nickel membrane, in non-steady-state surface limited regime

A better understanding of mutual influence among hydrogen isotope species in multi-isotope permeation is important for accurate assessments and predictions on tritium permeation through structural materials of fusion reactors. Moreover, this is important as the injection of H2 gas into the helium coolant of HCPB breeding blanket is proposed for mitigation of the permeation flux of tritium from the purge gas into the coolant. Although various modeling and experimental works have been carried out so far on this topic of multi-isotope permeation, unresolved issues or even controversies still persist. This work presents the results of some experimental tests of co-current permeation of deuterium with hydrogen through a very thin (0.075 mm) nickel membrane, performed in non-steady-state and surface limited regime (SLR), with the purposes to observe the effect of hydrogen on the permeation effective flux of deuterium, as well as to verify experimentally the predictions of a previous theoretical work. Thus, two deuterium/hydrogen gas mixtures of different ratios, as well as pure deuterium gas, were alternately introduced into the high-pressure side of the membrane by keeping the effective partial pressure of deuterium as close as possible to the same value (0.1 Pa), so that the comparison between multi- and mono-isotope permeation be relevant. The results indicate that the presence of (co-permeation) hydrogen does not lead to the decrease of deuterium permeation, but, on the contrary, to its increase. This effect is clearer revealed well before steady state is reached, where the effective permeation flux of deuterium has a constantly higher rise-rate when (co-permeation) hydrogen is present, and this rise-rate is even higher when the effective hydrogen pressure is higher. Also, a quite good consistency between experimental results and the theoretical predictions has been obtained, as well as a good repeatability of the results.

Transmission Kikuchi Diffraction Mapping Induces Structural Damage in Atom Probe Specimens.

Measuring local chemistry of specific crystallographic features by atom probe tomography (APT) is facilitated by using transmission Kikuchi diffraction (TKD) to help position them sufficiently close to the apex of the needle-shaped specimen. However, possible structural damage associated to the energetic electrons used to perform TKD is rarely considered and is hence not well-understood. Here, in two case studies, we evidence damage in APT specimens from TKD mapping. First, we analyze a solid solution, metastable β-Ti-12Mo alloy, in which the Mo is expected to be homogenously distributed. Following TKD, APT reveals a planar segregation of Mo among other elements. Second, specimens were prepared near Σ3 twin boundaries in a high manganese twinning-induced plasticity steel, and subsequently charged with deuterium gas. Beyond a similar planar segregation, voids containing a high concentration of deuterium, i.e., bubbles, are detected in the specimen on which TKD was performed. Both examples showcase damage from TKD mapping leading to artefacts in the distribution of solutes. We propose that the structural damage is created by surface species, including H and C, subjected to recoil from incoming energetic electrons during mapping, thereby getting implanted and causing cascades of structural damage in the sample.

Conceptual design of the Gas Injection and Vacuum System for DTT NBI

The Divertor Tokamak Test (DTT) is a new experimental facility whose construction is starting in Frascati, Rome, Italy; its main goals are improving the understanding of plasma-wall interactions and supporting the development of ITER and DEMO. DTT will be equipped with a Neutral Beam Injector (NBI) based on negative deuterium ions, designed to inject 10 MW of power to the tokamak.A fundamental system for the good operations of the DTT NBI will be its Gas injection and Vacuum System (GVS). Indeed, the efficiency of the entire NBI strongly depends on the good performance of its GVS.The GVS for DTT NBI will be composed of two systems working in parallel: a grounded section connected to the main vacuum vessel, and a high voltage part connected to the ion source vessel and working at −510 kV voltage. The grounded part will feature a fore vacuum system (given by screw and roots pumps) plus a high vacuum system based on turbo-molecular pumps located on the side walls of the vessel and Non-Evaporable Getter (NEG) pumps located inside the vessel on the upper and lower surfaces. On the other hand, the high voltage part will feature a fore vacuum system (given by two compact screw pumps mounted on the external surface for the ion source vessel) plus a high vacuum system based on turbo-molecular pumps also located on the sidewalls of the ion source vessel. A dedicated deuterium gas injection will feed the process gas to the ion source and the neutralizer.This paper gives a description of the conceptual design of the GVS for DTT NBI, and of the procedure followed to optimize this system considering the operational requirements and the other constraints of the DTT NBI.

Quasi-Isentropic Compression of Gaseous Helium and Deuterium in Spherical Structures at Terapascal Pressures

The results of four experiments on studying preliminarily statically compressed gaseous helium and deuterium during their subsequent compression in explosive spherical cascade structures providing quasi-isentropic gas compression are presented. For helium, the following parameters were achieved: in one experiment, the compression pressure is Pmean ≈ 4.9 TPa at a density ρmax ≈ 6.4 g/cm3 and the compression ratio is δ = ρ/ρ0 ≈ 320; in another experiment, Pmean ≈ 10.9 TPa, ρmax ≈ 10.3 g/cm3, and δ ≈ 470. For deuterium, these parameters are Pmean ≈ 3.4 TPa, ρmax ≈ 6.0 g/cm3, and δ ≈ 162 in one experiment and Pmean ≈ 13.3 TPa, ρmax ≈ 11.4 g/cm3, and δ ≈ 520 in another experiment. The gas density was determined by an X-ray method using the position of the boundaries of the steel shells compressing a gas. The experiments are simulated with a one-dimensional gasdynamic software package, in which the Kopyshev–Khrustalev equations of state are used for the gases under study. The pressures are determined using calculations, in which the dynamics of gas compression is satisfactorily simulated for the entire set of experiments.

Quasi-Isentropic Compression of Gaseous Helium and Deuterium in Spherical Structures at Terapascal Pressures

Quasi-Isentropic Compression of Gaseous Helium and Deuterium in Spherical Structures at Terapascal Pressures