Total Deuterium Research Articles

Effect of grain size on defect annealing in displacement-damaged tungsten

Pulsed laser deposition and subsequent thermal treatment were used to create compact tungsten layers with various grain sizes (1μm, 100 nm, and 10 nm). The layers were self-damaged at room temperature up to 0.23 dpa using 20.3 MeV W ions and annealed in vacuum at 473 K or 673 K prior to exposure to deuterium plasma to populate the surviving displacement defects. Thermal desorption spectroscopy was used to measure deuterium retention and study the desorption profile. Rate-equation modeling of the desorption spectra was performed to study the behavior of individual traps at both annealing temperatures. After annealing the 1μm and 100 nm samples at 473 K, the deuterium retention was found to decrease by 24% and 9%, respectively, whereas the total deuterium retention in the 10 nm sample did not change. Annealing at 673 K reduced total deuterium retention by additional 27%, 14%, and 34% in the case of the samples with a grain size of 1μm, 100 nm, and 10 nm, respectively.

Investigation of the Solid-State Interactions in Lyophilized Human G-CSF Using Hydrogen-Deuterium Exchange Mass Spectrometry.

Hydrogen/deuterium exchange mass spectrometry (HDX-MS) previously elucidated the interactions between excipients and proteins for liquid granulocyte colony stimulating factor (G-CSF) formulations, confirming predictions made using computational structure docking. More recently, solid-state HDX mass spectrometry (ssHDX-MS) was developed for proteins in the lyophilized state. Deuterium uptake in ssHDX-MS has been shown for various proteins, including monoclonal antibodies, to be highly correlated with storage stability, as measured by protein aggregation and chemical degradation. As G-CSF is known to lose activity through aggregation upon lyophilization, we applied the ssHDX-MS method with peptide mapping to four different lyophilized formulations of G-CSF to compare the impact of three excipients on local structure and exchange dynamics. HDX at 22 °C was confirmed to correlate well with the monomer content remaining after lyophilization and storage at -20 °C, with sucrose providing the greatest protection, and then phenylalanine, mannitol, and no excipient leading to progressively less protection. Storage at 45 °C led to little difference in final monomer content among the formulations, and so there was no discernible relationship with total deuterium uptake on ssHDX. Incubation at 45 °C may have led to a structural conformation and/or aggregation mechanism no longer probed by HDX at 22 °C. Such a conformational change was observed previously at 37 °C for liquid-formulated G-CSF using NMR. Peptide mapping revealed that tolerance to lyophilization and -20 °C storage was linked to increased stability in the small helix, loop AB, helix C, and loop CD. LC-MS HDX and NMR had previously linked loop AB and loop CD to the formation of a native-like state (N*) prior to aggregation in liquid formulations, suggesting a similar structural basis for G-CSF aggregation in the liquid and solid states.

Considerations on hydrogen isotopes release from thin films by laser induced ablation and laser induced desorption techniques

In this paper, we studied the release of deuterium atoms from 1 μm aluminum layers by Laser Induced Ablation and Laser Induced Desorption methods, using a 1053 nm laser source operating with 10 ns pulse duration and 1 kHz pulse repetition rate. The software control of the laser pulse energy successfully accomplished the transition from layer ablation to layer desorption. The layers have been produced by High Power Impulse Magnetron Sputtering technique on substrates with different surface properties.The amount of deuterium released from aluminum layers was evaluated by Quadrupole Mass Spectrometry after ablation respectively desorption of a small area of the sample exposed to the focused laser beam. The results were compared with the one obtained by Thermal Desorption Spectroscopy, which indicated a total amount of deuterium in the analyzed sample of about 2.6 × 1021 D at/m2. The mass spectra data revealed that 85% (2.2 × 1021 D at/m2) and 9% (0.2 × 1021 D at/m2) of total deuterium atoms released from the aluminum layer by Laser Induced Ablation and Laser Induced Desorption, respectively, were detected. The mathematical fitting of the experimental data indicated different laser fluences that boundary the desorption from ablation processes. Through analyses of the morphology of aluminum layer surfaces in connection with the substrate surface quality, the release of deuterium atoms by Laser Induced Ablation or Laser Induced Desorption processes can be identified.

Deuterium retention in helium-irradiated tungsten

Hot-rolled tungsten samples were first irradiated with helium ions with varying fluences or energies and then exposed to deuterium plasmas, and the influence of helium fluence (corresponding to damage levels of 0.12–2.3 dpa) and helium ion incident energy (50, 200, 400 keV) on deuterium retention were investigated. A significant increase of the total deuterium inventory was observed in the helium irradiated sample, and deuterium retention reaches saturation at 0.69–1.15 dpa. Radiation-induced defects and helium-vacancy complexes or helium bubbles contribute to the increase of deuterium inventory, and the effect of helium-vacancy complexes or helium bubbles is aggrandizement with the increase of damage level. Comparison of deuterium depth profiles of samples irradiated by helium ions with different incident energies reveals that the vast majority of deuterium is trapped in the helium accumulation region, and the depth of the maximum deuterium concentrations is consistent with the maximum helium concentrations rather than the damage levels. Furthermore, the total amount of deuterium increases with the increase of helium ions energy due to the deepening of the irradiation region.

Deuterium permeation through liquid tin supported by a nickel substrate

A model of deuterium permeation through liquid (liq.) Sn supported by a nickel (Ni) substrate is proposed as follows; deuterium dissolves in liq. Sn according to the Sieverts’ law and its concentration immediately becomes uniform through the liq. Sn layer due to large diffusivity of deuterium in liq. Sn. A thin intermediate Sn-Ni alloy layer is formed at an interface of liq. Sn and the Ni substrate in a transient of deuterium permeation. Deuterium concentration and diffusivity in the alloy layer would be lower than those in liq. Sn and pure Ni, resulting in lower deuterium permeability. Consequently, the intermediate Sn-Ni alloy layer could control total deuterium permeation through the liq. Sn supported by the Ni substrate.

Effect of anisotropic grain boundaries on the surface blistering of tungsten induced by deuterium plasma exposure

The effect of anisotropic grain boundaries on the surface microstructure changes and deuterium retention behavior in tungsten under deuterium plasma irradiation were studied. The samples named as NDW and RDW were cut from RD × TD plane and TD × ND plane of a rolled W plate (ND: normal direction, RD: rolling direction, TD: transverse direction), respectively. The results suggest that both surface morphology and deuterium retention in the RDW samples are suppressed compared to that of NDW samples for 1 h and 25 h deuterium irradiation. For 1 h exposure, the total deuterium retention in the NDW samples is about 1.6 times as much as that of RDW. However, as the exposure time increased to 25 h, the total deuterium retention in the NDW sample is two times the height of RDW sample. The experimental results show that the special grain structure of RDW can alleviate the surface morphology changes and decrease the deuterium retention in tungsten, which is interpreted by the lateral stress model of blistering.

Deuterium retention and desorption behavior of W-Ta-Cr-V high entropy alloy

Deuterium retention and desorption behavior of W-Ta-Cr-V films under deuterium plasma irradiation were studied. The W-Ta-Cr-V films were prepared on the molybdenum (Mo) substrate by magnetron sputtering. Subsequently, all films annealed at 1000 °C were exposed to deuterium plasma at a flux of 8.13 × 1019 D/m2·s for 9 h to achieve an irradiation fluence of 2.63 ×1024 D/m2. Electron backscattered diffraction (EBSD) was used to characterize the texture and average grain size of films. Doppler broadening spectrometry of positron annihilation (DBS-PA) was carried out with an energy-variable slow positron beam to detect the concentration of vacancy-type defects in the films. The results suggest that there are fewer vacancy-type defects inside W-Ta-Cr-V grains. Deuterium retention and the desorption behavior of W-Ta-Cr-V were studied by compared to pure tungsten films. In the 300–800 K temperature range, the peaks of thermal desorption spectroscopy (TDS) of W-Ta-Cr-V films are substantially consistent with that of the W films. Notably, in the range of 800 K-1000 K, W-Ta-Cr-V film has no thermal desorption peak. We attribute this to the large lattice distortion and low vacancy formation energy, which inhibit the growth of voids inside the grains of W-Ta-Cr-V films. The total deuterium retention of W-Ta-Cr-V films is compared with that of W films. It is measured by TDS that the deuterium retention of W-Ta-Cr-V films is nearly 5 times that of W films. Based on the analysis of the TDS spectra, the higher deuterium retention in W-Ta-Cr-V films is due to the more grain boundary defects.

Difference of co-extracted electron current and beam acceleration in a negative ion source with hydrogen-isotope ions

Improvement of the performance on a hydrogen/deuterium negative ion source for a nuclear fusion device is reported. In particular, the suppression of the co-extracted electron current, Ie, is an important issue to ensure the stable beam acceleration. Improvement of the Ie has been confirmed by optimizing the magnetic field of the electron deflection magnet in the extraction grid. Two other new methods for reduction of the Ie were validated. The first was an electron fence whose rods were set between the rows of apertures on a plasma grid. The electron and negative ion current ratio, approximately Ie/I acc, was greatly improved from 0.7 to 0.25 in deuterium. The second was an outer iron yoke which enhanced the magnetic flux density 19% inside the arc discharge chamber. The Ie/Iacc using the outer yoke decreased by 0.1 compared with using a normal magnetic filter in a deuterium operation. These attempts have improved the total deuterium injection beam power of 8.4 MW by three negative ion based NBIs.

Isotopic Substitution Reveals the Importance of Aluminate Diffusion Dynamics in Gibbsite (Al(OH)3) Crystallization from Alkaline Aqueous Solution

Understanding molecular-scale factors governing the precipitation of aluminum hydroxides, such as gibbsite, under alkaline conditions is important for the formation of laterite deposits, as well as aluminum processing. However, mechanisms enabling tetrahedral aluminate ions to assemble into octahedral sites of the gibbsite lattice remain unclear. Formation of oligomeric complexes has been hypothesized as a critical intermediate step. Here, we report a study of gibbsite solubility in highly alkaline solutions using deuterium substitution to probe equilibrium and kinetic factors that could affect oligomeric intermediate formation, including the reactivity and the diffusivity of aluminate ions. When substituting sodium hydroxide with sodium deuteroxide, solution analysis shows a nearly 40% and 50% increase in gibbsite solubility in 2.4 and 3.3 mol·kg–1 total sodium solutions, respectively. Raman spectroscopy indicated that monomeric aluminate ions are the predominant species in solution irrespective of deuteration. However, both 27Al and 23Na nuclear magnetic resonance (NMR) spectroscopy revealed significant differences in chemical shifts in deuterated solutions, and analysis of 1H, 23Na, and 27Al diffusion coefficients with pulsed-field gradient, stimulated echo NMR spectroscopy shows a decrease in ion diffusivity with increasing total deuterium in solution, consistent with the notion of increasing strength in the hydrogen/deuterium bonding network. Because the relative change in 1H diffusion coefficients are commensurate with the difference in apparent solubility constants, there is evidence for an oligomeric intermediate whose steady-state concentration is maintained by the collision frequency of aluminate ions.

Irradiation hardening behaviors of large-scale hot rolling potassium-doped tungsten alloy under synergistic irradiations of Fe11+ ion combined with deuterium and helium plasmas

In this study, a 25 kg potassium doped tungsten (KW) plate dispersed K bubbles was prepared by hot rolling firstly. In order to evaluate the mechanical properties of KW after irradiation, the synergistic irradiation of Fe11+ ion, He and D plasmas were performed on KW and pure tungsten (PW). 3.5-MeV Fe11+ ion irradiation was used to simulate displacement damage induced by neutrons. The total fluence and irradiation temperature were 5.31 × 1014 m−2 for 0.5 displacements per atom (dpa) damage and 400 K, respectively. Positron annihilation Doppler broadening spectrometry (PA-DBS) technique was applied to measure the type of defect in both undamaged and damaged PW & KW samples. The total ion fluence helium (He) and deuterium (D) were kept constant at 1 × 1025 He m−2 and 5 × 1024 D m−2, separately. Subsequently, the hardness value of PW and KW received from CSM nanoindentation technique was analyzed and compared. The results show that the increase of vacancy-type defects in KW is restrained after irradiation compared with PW. For un-irradiated PW and KW samples, there are almost the same pop-in events, which indicate that PW and KW a similar plastic deformation at room temperature. The KW shows a better irradiation hardening resistance than PW under the same irradiation condition. Besides, the evolution of irradiation hardening as well as their relationship with K bubbles were discussed in detail.

Surface modification and deuterium retention in rhenium doped tungsten exposed to low energy deuterium plasma

Surface modification and deuterium (D) retention in rhenium (Re) doped tungsten (Namely, W-5 wt.% Re) exposed to 100 eV deuterium plasma with a constant flux of 1.8 × 1021 D/m2/s were investigated. All the samples were exposed to D plasma at three types of exposure conditions, namely, exposure with doses of 1.3 × 1025 D/m2 and 2.6 × 1025 D/m2 at 470 K as well as exposure with dose of 5.2 × 1025 D/m2 at 506 K. Before irradiation, it was found that Re doping caused the decreases of hardness and lattice constant. As the samples were exposed to D plasma with the fluence of 1.3 × 1025 D/m2 at 470 K, many deuterium blisters with a size of tens nanometer were observed on surface of pure tungsten (W). While for W-Re alloy, only strip-like nanostructures can be found. Meanwhile, Re doping inhibited the surface blistering but increased total deuterium in W under this exposure condition. As the exposure fluence up to 2.6 × 1025 D/m2, it was found that both the blisters and total deuterium retention in W was restrained by Re doping. As the exposure fluence and temperature increased simultaneously, surface blistering on W-Re alloy was further suppressed compared to pure W.

Modelling of hydrogen isotopes trapping, diffusion and permeation in divertor monoblocks under ITER-like conditions

In this work, the deuterium (D) retention in plasma facing components of the divertor of ITER is estimated. Three scenarios are simulated with 3 different surface temperatures, 1456 K, 870 K and 435 K. They represent the exposure of different parts of the divertor during an attached plasma. Our 1D rate equation code MHIMS (migration of hydrogen in materials) is used to model the retention in the super-saturated layer formed in the first 10 nm: the D retention integrated in this 10 nm-layer is ≈1019 D m−2 for the coldest scenarios. It is also used to differentiate the evolution of deuterium retention during pulsed and continuous plasma exposures which shows that: (i) there is a retention during the ramp-down in the first 10 μm which is released during the ramp up and (ii) the bulk retention is not affected by the cycling of plasma exposure. The concentration of mobile deuterium in the implantation zone is used as an input of our finite element code FESTIM (finite element simulation of tritium in materials) which is used to assess the deuterium retention and migration in the 2D complex geometry of the actively cooled plasma facing components. In the end, this work enable to determine the three following macroscopic quantities: the total deuterium retention, the permeation flux to the cooling pipe and the desorption flux from the toroidal edges of the components. It is shown that (i) the coldest scenario leads to the highest retention despite the lowest exposure flux which has already been observed in past retention studies, (ii) the permeation to the cooling pipes happens after few thousands of seconds only for the hottest scenario, (iii) the release of deuterium from the toroidal edges is a small fuel recycling source.

A study of beam ion and deuterium–deuterium fusion-born triton transports due to energetic particle-driven magnetohydrodynamic instability in the large helical device deuterium plasmas

Understanding energetic particle transport due to magnetohydrodynamic instabilities excited by energetic particles is essential to apprehend alpha particle confinement in a fusion burning plasma. In the large helical device (LHD), beam ion and deuterium–deuterium fusion-born triton transport due to resistive interchange mode destabilized by helically-trapped energetic ions (EIC) are studied employing comprehensive neutron diagnostics, such as the neutron flux monitor and a newly developed scintillating fiber detector characterized by high detection efficiency. Beam ion transport due to EIC is studied in deuterium plasmas with full deuterium or hydrogen/deuterium beam injections. The total neutron emission rate (S n) measurement indicates that EIC induces about a 6% loss of passing transit beam ions and a 60% loss of helically-trapped ions. The loss rate of helically-trapped ions, which drive EIC, is larger than the loss rate of passing transit beam ions. Furthermore, the drop of S n increasing linearly with the EIC amplitude shows that barely confined beam ions existing near the confinement-loss boundary are lost due to EIC. In full deuterium conditions, a study of deuterium–deuterium fusion-born triton transport due to EIC is performed by time-resolved measurement of total secondary deuterium–tritium neutron emission rate (S n_DT). Drop of S n_DT increases substantially with EIC amplitude to the third power and reaches up to 30%. The relation shows that not only tritons confined in confined-loss boundary, but also tritons confined in the inner region of a plasma, are substantially transported.

Influence of neon seeding on the deuterium retention and surface modification of ITER-like forged tungsten

In order to investigate the effect of neon seeding on deuterium retention and surface modification of ITER-like forged tungsten with grains elongated perpendicular to the surface, pure and neon-seeded deuterium plasma exposures were performed in the linear plasma device PSI-2. The ion percentage of neon in the mixed plasma was around 10%. The sample temperature and deuterium ion fluence were kept at 450 K and 1 × 1026 m−2, respectively. The incident ion energy was 40 eV, just reaching the tungsten sputtering threshold for neon. Surface observations show that neon seeding leads to pronounced cracking and erosion of blister caps and a significant reduction of small blisters (<0.8 μm). This is possibly attributed to surface sputtering and the inhibitory effect of neon-induced defects on blister nucleation by hindering dislocation movements. On the other hand, neon seeding increases the total deuterium retention by ∼70% according to the thermal desorption spectroscopy (TDS) measurements. A low-temperature desorption peak (∼660 K) which should be mainly ascribed to deuterium de-trapping from dislocations is observed to be broadened and shifts towards higher temperature in the case of neon seeding, suggesting enhanced inward diffusion and trapping of deuterium. An additional deuterium release peak appears at a higher temperature (∼803 K), indicating the creation of new deuterium-traps induced by neon. A comparison of the results of nuclear reaction analysis and TDS reveals that neon seeding not only increases deuterium retention in the surface region (<7.2 μm) but also in the bulk (>7.2 μm). We ascribe the enhanced deuterium retention to the increased deuterium-traps in the top-surface induced by Ne irradiation and the vertical grain boundary configuration of the forged W promoting the inward diffusion of deuterium.

A quantitative study of retention and release of deuterium and tritium during irradiation of γ-LiAlO2 pellets

This study reports on the quantification of deuterium in ion-irradiated γ-LiAlO2 pellets as a function of dose and temperature. The γ-LiAlO2 pellets were sequentially irradiated with He+ and D2+ ions to the same fluences of 5 × 1016, 1 × 1017 and 2 × 1017 He+ + D+/cm2 at 188 K. Additional irradiation was performed to 1 × 1017, 2 × 1017 and 4 × 1017 He+ + D+/cm2 at 573 K. A set of the pellets irradiated at 188 K was shipped and stored at low temperatures from 80 to 132 K and characterized using time-of-flight secondary ion mass spectrometry at ~173 K. The deuterium depth profiles show a Gaussian-like distribution in the low-temperature pellets. The total deuterium retention is found to be directly proportional to the ion fluence. About 27 at.% of the implanted deuterium atoms were released from the pellet irradiated to 2 × 1017 He+ + D+/cm2 at 188 K during storage at room temperature for ~1 month. The measured deuterium retention is found to increase initially with ion fluence and tend to saturate at high fluences during ion irradiation at 573 K. The amount of the released deuterium is observed to be quantitatively consistent with that of the released tritium from the standard pellets during neutron irradiation at 573 K.

Influences of displacement damage due to heavy ion irradiation on deuterium retention in CLF-1 steel

Abstract In this study, the structure damage and its influence on deuterium retention in the reduced-activation ferritic martensitic (RAFM) steel were investigated using heavy ions to simulate the displacement damage caused by neutron irradiation. Iron (Fe) and nickel (Ni) ions were applied as self-ions and other ions to irradiate steel samples. After Fe or Ni heavy ion irradiation, some amorphous cluster structures were evident, especially at the peak displacement damage region located at a depth of around 1.0 µm in the CLF-1 steel. When the displacement damage was higher than 2.0 dpa, the grain boundaries or boundary structures became obscured by the formation of other defects, such as dislocation clusters for samples irradiated by either Fe or Ni ions. The damaged samples irradiated by Fe or Ni heavy ions were exposed to deuterium plasma, and the deuterium release and retention behaviors were measured. The results showed that after being irradiated by Ni ions, the deuterium release peak increased with no changes of the release temperature. However, after Fe ions irradiation, the deuterium release peaks shifted to lower temperatures corresponding to an increase in the number of the low-energy capture sites, such as dislocations. The increase in the total deuterium retention in CLF-1 steel after heavy ion irradiation was less than 56%, which was much lower than those of tungsten materials.

Surface Structure Modification and Deuterium Retention in Tungsten under Pulsed Plasma Loads

Modification of the surface layer and deuterium accumulation in tungsten targets under plasma irradiation in a quasi-stationary plasma accelerator with an intrinsic magnetic field QSPA-T, which reproduces the conditions (plasma thermal load of 0.2-5 MJ/m2, pulse duration of 0.1-1.2 ms) typical of ELM events in ITER, are studied. Using a scanning electron microscope, structure modifications at the surface and in the bulk after deuterium plasma irradiation are analyzed. The observed changes in the near-surface layer are compared with the calculated data on the change in the internal structure of tungsten under intense thermal action obtained as a result of the numerical solution of the heat conduction problem. The total deuterium retention in the samples was measured using thermal desorption spectroscopy, and it was in the range of (3-4) × 1016 particles/cm2 for the samples melted during plasma exposure. These numbers exceed by an order of magnitude the values obtained for samples without traces of melting.

Comparative study of deuterium retention in irradiated Eurofer and Fe–Cr from a new ion implantation materials facility

A new facility to study the interaction of hydrogen isotopes with nuclear fusion-relevant first wall materials, and their retention and release, has been produced. The new facility allows for implanting a range of gases into samples, including tritium. An accurate study of isotope effects, such as the isotopic exchange in damaged microstructure, has previously been difficult due to a background signal of light hydrogen. This new capability will allow virtually background free measurements using tritium and deuterium. The design and build of this facility are described and commissioning results are presented. Within the UKAEA-led tritium retention in controlled and evolving microstructure (TRiCEM) project, this facility is used for the comparative study of deuterium retention in self-ion irradiated Eurofer steel and Fe–Cr alloy. Self-ion bombardment with energies of 0.5 MeV is used to mimic the defects created by neutrons in fusion power plants and the created traps are then filled with deuterium in the new facility. Implanted samples are analysed using thermal desorption spectrometry (TDS), secondary ion mass spectrometry (SIMS), and transmission electron microscopy. Results on the total deuterium content as a function of time, TDS spectra and SIMS analysis are presented. A comparison of the results for Eurofer and Fe–Cr revealed several differences. While some of them may be due to experimental details like different time delays between exposure and analysis, others, such as deuterium retention as function of dose, might be genuine and require further studies.

Practical and reliable synthesis of 2′,3′,5′,5″-tetradeuterated uridine derivatives

Deuterated drugs are valuable in the fields of drug discovery and medicinal chemistry. 2′,3′,5′,5″-tetradeuterated uridine derivatives were synthesised from 2,3,5,5′-selectively tetradeuterated ribose using Sajiki’s H–D exchanged Ru/C–H2–D2O–NaOH system and silyl–Hilbert–Johnson methods. The total deuterium content of the tetradeuterated uridines was over 92% using either basic or acidic reaction conditions. These derivatives would be expected as building blocks for the synthesis of deuterium-substituted nucleic acid probes for tracking the pharmacokinetics of nucleic acid drugs.

Analysis of 3D deuterium ion emission angular distribution in plasma focus device using novel panorama polycarbonate detectors

Panorama mega-size polycarbonate ion image detectors (MS-PCID) were used for the first time in this study to detect images of deuterium ion emission angular distributions in a 3.5 kJ plasma focus device (PFD) space, as processed by novel panorama single-cell electrochemical etching systems. Images of ion emission angular distribution were analyzed from which infinite points can be selected in an image formed under a single pinch shot. By analyzing deuterium ion images formed on the polycarbonate cylindrical detector (~3500 cm2 effective area), which covers PFD top base and cylindrical wall, deuterium ion emission seems isotropic and symmetrical in ~4π PFD space with a dip on z-axis. Total deuterium ion tracks registered on the cylindrical polycarbonate detector was estimated ~4.2 × 1010 per shot. Isotropic deuterium emission with such a high fluence, makes whole PFD space available for wide range of wide-scale applications, what has been limited with common small solid angle ion emission understanding.