Solubility Of Deuterium Research Articles

Hydrogen and Deuterium Solubility, Diffusivity and Permeability from Sorption Measurements in the Ni33Ti39Nb28 Alloy.

The hydrogen/deuterium sorption properties of Ni33Ti39Nb28 synthesized by the vacuum induction melting technique were measured between 400 and 495 °C for pressure lower than 3 bar. The Sieverts law is valid up to H(D)/M < 0.2 in its ideal form; the absolute values of the hydrogenation/deuteration enthalpy are ΔH(H2) = 85 ± 5 kJ/mol and ΔH(D2) = 84 ± 4 kJ/mol. From the kinetics of absorption, the diffusion coefficient was derived, and an Arrhenius dependence from the temperature was obtained, with Ea,d = 12 ± 1 kJ/mol for both hydrogen isotopes. The values of the alloy permeability, obtained by combining the solubility and the diffusion coefficient, were of the order of 10-9 mol m-1 s-1 Pa-0.5, a value which is one order of magnitude lower than that of Ni41Ti42Nb17, until now the best Ni-Ti-Nb alloy for hydrogen purification. In view of the simplicity of the technique here proposed to calculate the permeability, this method could be used for the preliminary screening of new alloys.

Promising Isotope Effect in Pd77Ag23 for Hydrogen Separation

Pd–Ag alloys are largely used as hydrogen separation membranes and, as a consequence, the Pd–Ag–H system has been intensively studied. On the contrary, fewer information is available for the Pd–Ag–D system; thus, the aim of this work is to improve the knowledge of the isotope effect on the commercial Pd77Ag23 alloy, especially for temperature above 200 °C. In particular, deuterium absorption measurements are carried out in the Pd77Ag23 alloy in the temperature range between 79 and 400 °C and in the pressure range between 10−2 and 16 bar. In this exploited pressure (p) and composition (c) range, above 300 °C the pc isotherms display the typical shape of materials where only a solid solution of deuterium is present while at lower temperatures these curves seem to be better described by the coexistence of a solid solution and a deuteride in a large composition range. The obtained results are compared and discussed with the ones previously measured with the lightest hydrogen isotope. Such a comparison shows that the Pd77Ag23 alloy exhibits a clear inverse isotope effect, as the equilibrium pressure of the Pd–Ag–D system is higher than in Pd–Ag–H by a factor of ≈2 and the solubility of deuterium is about one half of that of hydrogen. In addition, the absorption measurements were used to assess the deuteration enthalpy that below 300 °C is ΔHdeut = 31.9 ± 0.3 kJ/mol, while for temperatures higher than 300 °C, ΔHdeut increases to 43 ± 1 kJ/mol. Additionally, in this case a comparison with the lighter isotope is given and both deuteration enthalpy values result lower than those reported for hydrogenation. The results described in this paper are of practical interest for applications operating above 200 °C, such as membranes or packing column, in which Pd77Ag23 has to interact with a gas stream containing both hydrogen isotopes.

Behavior of light elements in iron-silicate-water-sulfur system during early Earth\u2019s evolution

Hydrogen (H) is considered to be one of the candidates for light elements in the Earth’s core, but the amount and timing of delivery have been unknown. We investigated the effects of sulfur (S), another candidate element in the core, on deuteration of iron (Fe) in iron–silicate–water system up to 6–12 GPa, ~ 1200 K using in situ neutron diffraction measurements. The sample initially contained saturated water (D2O) as Mg(OD)2 in the ideal composition (Fe–MgSiO3–D2O) of the primitive Earth. In the existence of water and sulfur, phase transitions of Fe, dehydration of Mg(OD)2, and formation of iron sulfide (FeS) and silicates occurred with increasing temperature. The deuterium (D) solubility (x) in iron deuterides (FeDx) increased with temperature and pressure, resulting in a maximum of x = 0.33(4) for the hydrous sample without S at 11.2 GPa and 1067 K. FeS was hardly deuterated until Fe deuteration had completed. The lower D concentrations in the S-containing system do not exceed the miscibility gap (x < ~ 0.4). Both H and S can be incorporated into solid Fe and other light elements could have dissolved into molten iron hydride and/or FeS during the later process of Earth’s evolution.

Solubility of deuterium and hydrogen in fcc iron at high pressures and temperatures

An isobar $x(T)$ of deuterium solubility in iron is constructed at $P=6.3\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$ and $100\ensuremath{\le}T\ensuremath{\le}800{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ based on the results of thermal desorption analysis of $\mathrm{Fe}{\mathrm{D}}_{x}$ samples produced by quenching under high ${\mathrm{D}}_{2}$ pressure to the temperature of liquid nitrogen. The experiment confirms the value of $x=0.64$ at $T=715{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ proposed previously in a neutron diffraction work [Machida et al., Nature Commun. 5, 5063 (2014)] for \ensuremath{\gamma} iron deuteride under the assumption that deuterium atoms occupy both octa- and tetrahedral interstices in its fcc metal lattice. An estimate of $\mathrm{\ensuremath{\Delta}}V/x=2.2\phantom{\rule{0.16em}{0ex}}{\AA{}}^{3}/\mathrm{atom}$ D made in that work for the deuterium-induced volume expansion $\mathrm{\ensuremath{\Delta}}V(x)$ of fcc iron is also confirmed. To prove that the absorption of protium leads to a similar volume expansion, we constructed an isotherm $x(P)$ of hydrogen solubility in fcc iron at $T=600{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ and ${\mathrm{H}}_{2}$ pressures from 4.3 to 7.4 GPa. The available $\mathrm{\ensuremath{\Delta}}V(P,T)$ data of in situ x-ray diffraction studies of iron hydrides [T. Hiroi et al., J. Alloys Compd. 404--406, 252 (2005); H. Saitoh et al., J. Alloys Compd. 706, 520 (2017)] agree with this isotherm under the assumption that $\mathrm{\ensuremath{\Delta}}V/x=2.2\phantom{\rule{0.16em}{0ex}}{\AA{}}^{3}/\mathrm{atom}$ H. The transformation between the high-temperature fcc (\ensuremath{\gamma}) and low-temperature dhcp (\ensuremath{\epsilon}\ensuremath{'}) deuterides of iron is shown to occur at 260 \ifmmode^\circ\else\textdegree\fi{}C, which is approximately 100 \ifmmode^\circ\else\textdegree\fi{}C lower than the temperature of the \ensuremath{\gamma} \ensuremath{\leftrightarrow} \ensuremath{\epsilon}\ensuremath{'} transformation in the Fe-H system at the same pressure of 6.3 GPa.

Distributed detection of hydrogen and deuterium diffusion into a single-mode optical fiber with chirped-pulse phase-sensitive optical time-domain reflectometry.

For some infrastructures such as oil and gas extraction boreholes or radioactive waste repositories, where distributed optical fiber sensors are employed to grant the safety of the facilities, the presence of gas species such as hydrogen or deuterium is one of the most relevant parameters to monitor. The possibility of employing the same kind of sensors for this purpose is of special interest, reducing the cost by employing a single interrogator, able to measure multiple parameters by simply employing adequate sensing fibers. To meet this goal, we present here a chemical sensor based on chirped-pulse phase-sensitive optical time-domain reflectometry (CP-φOTDR), which is able to detect these species while they diffuse into the silica fiber. The ability of chirped-pulse φOTDR to measure a change in refractive index with sensitivity around 10-8 has allowed determining hydrogen concentration with accuracy on the order of 10-3 mol/m3 and spatial resolution ∼6 m. Another experiment provides an indirect measurement of the solubility of deuterium in a standard telecom-grade optical fiber, which is found to be around 1.47×1024 m3/bar.

Modeling the sharp deuterium release from beryllium co-deposits

Many studies have shown a sharp deuterium desorption from beryllium at around 450 K. In an attempt to model this sharp release, a new model was developed, describing the formation and decomposition of beryllium deuteride. Such a model was found to reproduce the sharp desorption peak in the thermal desorption spectrum. Moreover, in contrast to other models, the new model was able to reproduce the constant deuterium desorption from beryllium held at a constant elevated temperature. Fitting the modeling results to experimental data allowed us to determine the deuterium solubility limit in beryllium, which indicated an endothermic formation of beryllium deuteride. New values of the deuterium surface recombination coefficient were also obtained, differing from the ones found in the literature.

Estimation and Mode Selection of Deuterium Flux Supply into Ampoule Device Through Diffusion Filter in Experiments with Pb15.7Li Eutectic at the IVG1.M Reactor

One of the most promising materials to produce tritium in fuel cycle of fusion facilities is the lead-lithium eutectic Pb15.7Li. Tritium will be generated in nuclear reactions in a lithium-containing material under the influence of neutron irradiation. However, nowadays a limited number of studies have been conducted with the eutectic of such a composition (with a lithium content of 15.7%) and consequently, there is a lack of data on mechanisms of tritium generation and release from Pb15.7Li. In this regard, there is an urgent necessity for research of tritium generation and release from Pb15.7 Li directly under neutron irradiation conditions. For these studies a differential method will be used, which consists in follows: a controlled flux of spectrally pure deuterium will be continuously fed into the experimental cell with the eutectic sample during the reactor experiment. The regulated flux of deuterium will be fed to the experimental cell with the Pb15.7Li sample using diffusion palladium-silver filter. The article describes the process of determination of deuterium flux supply modes into the experimental cell. The temperature dependences of deuterium penetration through diffusion palladium-silver filter are presented. The coefficients of diffusion, solubility and permeability of deuterium through a palladium-silver filter are estimated and the activation energies of these processes as well as the Arrhenius dependence are presented.

Hydrogen and Deuterium Solubility in Commercial Pd–Ag Alloys for Hydrogen Purification

Pd–Ag alloys with compositions close to 23–25% Ag are considered as a benchmark for hydrogen permeability. They are used in small scale reactors for hydrogen separation and purification. Permeability and solubility are strictly mathematically correlated, and the temperature dependence of solubility can provide useful information about the physical state of the material, the hydrogenation enthalpy, and the occurrence of different thermodynamic states. While the permeability of Pd–Ag alloys has been largely investigated, solubility measurements are available only in a restricted temperature range. In this paper, we extend solubility measurements up to 7 bar for Pd77Ag23 in the temperature range between 25 °C and 400 °C and for Pd30Ag70 for temperatures between 190 °C and 300 °C. The occurrence of solid solutions or hydride phases is discussed, and the hydrogenation enthalpy is calculated.

Effect of external stress on deuteride (hydride) precipitation in Zircaloy-4 using in situ neutron diffraction

In situ neutron diffraction is utilized to study the deuteride (hydride) precipitation behavior in a cold-worked stress-relieved (CWSR) Zircaloy-4 material upon cooling from 420 °C to room temperature with a 78 MPa external stress applied along the rolling direction (RD) of the material. Two banks detector capture the diffraction signal from two principal directions of the specimen, the normal direction (ND) and the rolling direction (RD). The evolution of deuterium concentration in zirconium solid solution along the two specimen directions is measured by studying the δ-(220) peak intensity, applying the Rietveld refinement method to the diffraction data and using the measured zirconium c-axis lattice distortion. The deuterium concentration is observed to be higher for zirconium grains in the ND than the RD. The terminal solid solubility of precipitation (TSSp) for deuterium in the solution is then described using the Arrhenius equation. It is observed that the applied stress reduces the energy term Q in the Arrhenius equation when compared with the unstressed Q values from the work of others. A model by Puls is applied to study the effect of stress on deuterium solubility, with polycrystalline hydride precipitation strain calculated using the Kearns factor representative of the studied material. The experimental result does not agree with the model prediction of Puls.

Hydrogen-isotope transport in an ELBRODUR G CuCrZr alloy for nuclear applications in heat sinks

We present the first complete data set of the transport parameters (permeability, diffusivity, and solubility) of hydrogen and deuterium in an ELBRODUR G precipitation hardened CuCrZr alloy experimentally measured by using the time-dependent gas-phase technique in an elevated temperature range of 300–600 °C for nuclear applications in heat sinks. Using the measured values for hydrogen and deuterium and a quantum mechanical model based on a harmonic approximation, an extrapolation for tritium is also presented. The isotope effect ratios for the transport parameters were also estimated. Furthermore, our hydrogen results for ELBRODUR G were compared with the results for other copper alloys previously reported by other authors.

Hot vacuum extraction-isotopic dilution mass spectrometry for determination of hydrogen isotopes in zircaloys

A hot vacuum extraction-isotope dilution mass spectrometry (HVE-IDMS) was studied for determination of hydrogen isotopes in zirconium metal and alloys as nuclear reactor materials. A theoretical assessment of the completeness of the extraction of hydrogen isotopes under the chosen condition was carried out based on the hydrogen and deuterium solubility data for zirconium. The optimal isotopic spiking condition for conventional IDMS was further explored for the special case IDMS where the isotope abundance of the samples is varied and non-natural. Applying the optimal conditions, the accurate IDMS determination was realized. The agreement between the measured values and the certified or prepared values of standard reference materials and homemade standard materials validate the method developed.

Effect of deuterium on thin-film formation during tungsten sputtering in magnetron discharge deuterium plasma

The features of the formation of tungsten-deuterium films on a silicon substrate during the sputtering of a tungsten target in magnetron discharge deuterium plasma are studied. Scanning electron microscopy reveals the presence of blistered regions on the surface of the film; the concentration of these regions depends on the target-substrate distance. This distance is also responsible for the concentration of deuterium trapped in the films, which is determined by elastic recoil detection analysis. It is assumed that the deuterium retained by the film is located in pores and surface blisters that form the observed bulged regions. A possible cause of the formation of blisters and pores is the low solubility of deuterium in the Si substrate and the W film.

In-situ neutron powder diffraction on TiF3 catalysed magnesium for hydrogen storage applications

In situ powder neutron diffraction was used to study the hydrogen/deuterium sorption behaviour and microstructure of magnesium powders catalysed by 15 wt-%TiF3 during various stages of Mg to MgD2 phase transformation and vice versa. The presence of Ti fluoride catalyst appears to modify the thermodynamics of Mg-D in a way that the uptake of deuterium in α-Mg has become energetically more favourable and the β-MgD2 has become energetically less favourable. This modification in the system’s thermodynamics may result in the observed extended deuterium solubility limit for TiF3 catalysed Mg.

Deuterium transport and isotope effects in type 316L stainless steel at high temperatures for nuclear fusion and nuclear hydrogen technology applications

We present the first complete data set for the permeability, diffusivity, and solubility of both deuterium and hydrogen in 316L stainless steel (316L SS) obtained over a wide temperature range of 350–850 °C that accommodates both nuclear fusion and nuclear hydrogen technology applications. The deuterium results were also compared with the hydrogen results to estimate the isotope effect. The isotope effect ratio for diffusivity was different from the classical prediction. Furthermore, some of our results were compared with the results previously reported for 316 SS. Results and discussion are presented with an emphasis on the deuterium permeation and isotope effects.

Evaluation of deuterium permeation reduction factor of various coatings deposited on ferritic/martensitic steels for development of tritium permeation barrier

Evaluation of tritium permeation reduction performance of various coatings such as amorphous CrPO 4, plasma sprayed zirconium oxide ZrO 2 and gold plating was examined by means of deuterium permeation experiment and thermal stress analysis. As the results, ZrO 2 showed relatively good permeation reduction performance about 1/10, and results indicated that deuterium permeates through the grain boundaries and/or cracks formed in the ZrO 2 coating. Improvement such as filling diffusion paths will be effective for further permeation reduction performance. On the other hand, gold plating showed excellent permeation reduction performance around 550 K. Permeation reduction by gold plating would be attributed to low solubility of deuterium in gold. Additionally, results of thermal stress analysis were consistent with the results of permeation experiment. Therefore, thermal stress analysis could be an effective method for the selecting permeation reduction coatings prior to the permeation experiment.

The solubility of hydrogen and deuterium in alloyed, unalloyed and impure plutonium metal

Pressure-Composition-Temperature (PCT) data are presented for the plutonium-hydrogen (Pu-H) and plutonium-deuterium (Pu-D) systems in the solubility region up to terminal solubility (precipitation of PuH2). The heats of solution for PuHS and PuDS are determined from PCT data in the ranges 350-625°C for gallium alloyed Pu and 400-575°C for unalloyed Pu. The solubility of high purity plutonium alloyed with 2 at.% gallium is compared to high purity unalloyed plutonium. Significant differences are found in hydrogen solubility for unalloyed Pu versus gallium alloyed Pu. Differences in hydrogen solubility due to an apparent phase change are observable in the alloyed and unalloyed solubilities. The effect of iron impurities on Pu-Ga alloyed Pu is shown via hydrogen solubility data as preventing complete homogenization.

Temperature−Pressure Phase Diagram of a D2O−D2 System at Pressures to 1.8 kbar

Using a volumetric technique, the deuterium solubility, X, in heavy water (L), low-pressure hexagonal ice (I h), and high-pressure cubic clathrate ice (sII) is studied at deuterium pressures up to 1.8 kbar and temperatures from -40 to +5 degrees C. The triple point of the L + I(h) + sII equilibrium is located at P = 1.07(3) kbar and T = -4.5(8) degrees C. The molar ratios D2/D2O of phases at the triple point are X(L) = 0.020(5), X(Ih) = 0.012(5), and X(sII) = 0.207(5).

Solubilities of H2 in H2O and D2 in D2O with dissolved boric acid and lithium hydroxide

The solubilities of hydrogen (H2 and D2) in aqueous (H2O and D2O) solutions of lithium hydroxide or boric acid have been measured in the temperature range 25–80 °C. Lithium hydroxide and boric acid cause a salting-out effect for H2 and D2. The solubilities of H2 and D2 in aqueous electrolyte solutions exhibit similar responses to temperature changes as those for pure water. The solute specific parameter (hi) for boric acid in light and heavy water is 0.07 ± 0.02 and 0.48 ± 0.26 m3 kmol–1, respectively.Key words: hydrogen solubility, deuterium solubility, salting-out effect.

Diffusion and Permeation of Deuterium in EUROFER97: Effect of Irradiation and of Implanted Helium

Permeability, diffusivity, and solubility of deuterium in the low-activation martensitic stainless steel EUROFER97 were derived from measurements of gas permeation in the transient and steady-state regimes at temperatures from 100 to 350°C and at pressures from 2 × 103 to 2 × 105 Pa. The specimens were used in four conditions to investigate the effect of irradiation-induced defects: standard annealed condition, preirradiated with protons, implanted with helium, and implanted plus annealed to produce helium bubbles. In general, displacement defects as well as implanted helium tend to decrease permeation and diffusivity. Permeation and diffusion measurements were also performed under simultaneous irradiation, showing no net effect if the slight temperature increase due to irradiation is taken into account. Diffusion measurement of implanted hydrogen gave equal or slightly lower values than gas permeation, which is in qualitative agreement with results from preirradiated specimens. Trapping parameters are derived by a detailed comparison to a saturable-trap model. Results are compared to previous studies on 7%Cr F82H and 11%Cr MANET-II steels, and effects of compositional variations are indicated.

The Influence of Self-Stresses on the Deuterium Diffusion in Pd77Ag23 Membrane

The permeation of deuterium through the palladium-silver Pd77Ag23membrane was investigated. The diffusion coefficients of deuterium were determined at four temperatures between 303 and 328 K. The influence of self-stresses, created after introduction of deuterium into membrane with some initial deuterium contents, on the diffusion of deuterium was investigated at temperature 303.2 K. The solubility of deuterium in Pd77Ag23membrane at four temperatures in the range 303-328 K was measured.