Heavy Water Solutions Research Articles

Heavy Water Microdroplet Surface Enriches the Lighter Isotopologue Impurities.

Water microdroplets promote unusual chemical reactions at the air-water interface. However, the interfacial structure of water microdroplets and its potential influence on chemical processes are still enigmatic. Here, we present evidence of in-droplet fractionation of water isotopologues. Employing a sonic spray, we atomized the heavy water (D2O, 99.9 atom % D) solution of three classes of organic compounds (basic, acidic, and neutral). The analytes were predominantly desorbed from the resulting droplet surface in protonated form rather than deuterated form, as detected by mass spectrometry. This result remained unaltered upon adding formic acid-d2 (DCOOD) to the droplet. Monitoring Dakin oxidation of benzaldehyde at the surface of binary microdroplets composed of 1:1 (v/v) D2O/H218O revealed the preferred formation of phenolate-16O over phenolate-18O. Atmospheric pressure chemical ionization mass spectrometric analysis of the vapor composition in the sprayed aerosol revealed the preferential evaporation of lighter water isotopologue impurities from the surface of heavy water microdroplets. These results indicate the enrichment of lighter water isotopologue impurities (HOD/H2O) on the surface of heavy water microdroplets, implying possible future developments for water isotopologue fractionation using microdroplets.

Hydrogen and deuterium adsorptions and their equilibrium isotope effect on tungsten in alkaline solutions

The equilibrium isotope effect (EIE) of hydrogen isotopes (H and D) on the W electrode in alkaline aqueous (H2O) and heavy water (D2O) solutions was empirically studied based on the relevant electrochemical adsorption isotherms, which were determined using the phase-shift method and electrochemical impedance spectra. For a fractional surface coverage range of 0.2 < θ < 0.8, the potential differences (ΔE) for hydrogen isotope adsorptions on the W electrode were 70 mV, which were much lower than those on the Ni, Ti, Pd, and Rh electrodes. Furthermore, the value of EIE on the W electrode was 13.4, significantly higher than that on the Ti and most Pt-group metal (Pt, Ir, Pt–Ir alloy, and Rh) electrodes. The W electrode can therefore be considered as a potential electrocatalyst for optimizing the hydrogen and deuterium evolution reactions (HER and DER) and EIE of hydrogen isotopes, particularly in water electrolysis and the hydrogen isotope effect.

Linear orthobaric-density approach to the Krichevskii parameter of a solute from its vapor-liquid distribution coefficient: What can we learn about its accuracy from systems whose precise behavior is known?

We invoke the thermodynamic description of the solvation behavior of two limiting-case model solutes in highly-compressible environments of a real solvent to address the issue identified in the subtitle of this manuscript. We probe the effect of small experimental uncertainties in the vapor-liquid distribution constant of a dilute solute on the regressed limiting orthobaric-density slope by interrogating how this slope deviates from the theoretically-expected known values. The approach becomes feasible because we have developed the solvation thermodynamics of two limiting-case solute-solvent intermolecular asymmetries, i.e., the ideal gas solute and the solute behaving as another real solvent species, whose exact results provide unambiguous answers. We also uncover the non-monotonic dependence of the orthobaric-density slope of the vapor-liquid distribution constant involving the ideal gas solute in either light- or heavy-water solutions, a behavior that conspires against the key hypothesis behind the linear regression approach and the accuracy of the resulting Krichevskii parameters. Moreover, we reveal the significant water H/D−substitution effect on the orthobaric-density range of validity of the linear density representation for the vapor-liquid distribution constant of a solute.

Reproducible and Repeatable Generation of 4-He, γ-rays, and Heat in Light and Heavy Waters at Room Temperature

The extraordinary claim of observing nuclear fusion products and excess heat during heavy water electrolysis at room temperature was sensationalized in 1989. Unfortunately, it was rejected quickly by scientific communities. At the last attempt to access the accuracy of the previous works in this field, a Google-funded team tried to examine all reported works with their corresponding conditions to confirm the claimed results. Finally, they found that there was no reasonable proof of nuclear fusion reactions under the reported conditions. Here, we introduced a method to apply a unique triggering potential waveform to a simple two micro-shaft system in both heavy and light concentrated salinity waters which resulted in detecting 4-helium, gamma rays, and heat repeatedly and reproducibly. In this work, two types of nuclear fusion reactions were observed: 1) A D + D fusion reaction in potassium halide salt solutions in heavy water and 2) a new type of fusion reaction in carbon-containing salt solutions in both light and heavy waters. In the latter type, it was proved that the existence of carbon atoms in an anion structure is critical to observe the 4-helium, gamma rays, and heat.

Influence of Kosmotrope and Chaotrope Salts on Water Structural Relaxation.

The structural relaxation in water solutions of kosmotrope (structure maker) and chaotrope (structure breaker) salts, namely sodium chloride, potassium chloride, and cesium chloride, were studied through quasielastic neutron scattering measurements. We found that the collective dynamics relaxation time at the structure factor peak obtained using heavy water solutions shows a distinctively different behavior in the kosmotrope as opposed to the chaotrope solutions, increasing with the salt concentration in the former and decreasing in the latter. In both cases the trends are proportional to the concentration dependence of the relative viscosity of the solutions. These results indicate that kosmotropes and chaotropes influence the solution's viscosity by impacting in opposite ways the hydrogen bond network of water, strengthening it in one case and softening it in the other.

Molecular Dynamics and Neutron Scattering Studies of Potassium Chloride in Aqueous Solution.

Neutron diffraction with isotopic substitution (NDIS) experiments were done on both natural abundance potassium and isotopically labeled 41KCl heavy water solutions to characterize the solvent structuring around the potassium ion in water. Preliminary measurements suggested that the literature value for the coherent neutron scattering length (2.69 fm) for 41K was significantly in error. This value was remeasured using a neutron powder diffractometer and found to be 2.40 fm. This revision increases significantly the contrast between the natural abundance K and 41K by about 30% (from 1.0 to 1.3 fm). The experimentally determined structure factor of the potassium ion was then compared to that calculated from molecular dynamics (MD) simulations. Previous neutron scattering measurements of potassium gave a solvation number of 5.5 (see below). In this study, the NDIS and MD results are in good agreement and allowed us to derive a coordination number of 6.1 for water molecules and 0.8 for chloride ions around each K+ ion in 4 molal aqueous KCl solution.

On the Hydration of Heavy Rare Earth Ions: Ho3+, Er3+, Tm3+, Yb3+ and Lu3+-A Raman Study.

Raman spectra of aqueous Ho3+, Er3+, Tm3+, Yb3+, and Lu3+-perchlorate solutions were measured over a large wavenumber range from 50–4180 cm−1. In the low wavenumber range (terahertz region), strongly polarized Raman bands were detected at 387 cm−1, 389 cm−1, 391 cm−1, 394 cm−1, and 396 cm−1, respectively, which are fairly broad (full widths at half height at ~52 cm−1). These isotropic Raman bands were assigned to the breathing modes, ν1 Ln–O of the heavy rare earth (HRE) octaaqua ions, [Ln(H2O)8]3+. The strong polarization of these bands (depolarization degree ~0) reveals their totally symmetric character. The vibrational isotope effect was measured in Yb(ClO4)3 solutions in H2O and D2O and the shift of the ν1 mode in changing from H2O to D2O further supports the character of the band. The Ln–O bond distances of these HRE ions (Ho3+, Er3+, Tm3+, Yb3+, and Lu3+) follow the order of Ho–O > Er–O > Tm–O > Yb–O > Lu–O which correlates inversely with the band positions of the breathing modes of their corresponding octaaqua ions [Ln(OH2)8]3+. Furthermore, the force constants, kLn–O, were calculated for these symmetric stretching modes. Ytterbium perchlorate solutions were measured over a broad concentration range, from 0.240 mol·L−1 to 2.423 mol·L−1, and it was shown that with increasing solute concentration outer-sphere ion pairs and contact ion pairs were formed. At the dilute solution state (~0.3 mol·L−1), the fully hydrated ions [Yb(H2O)8]3+ exist, while at higher concentrations (CT > 2 mol·L−1), ion pairs are formed. The concentration behavior of Yb(ClO4)3 (aq) shows similar behavior to the one observed for La(ClO4)3(aq), Ce(ClO4)3(aq) and Lu(ClO4)3(aq) solutions. In ytterbium chloride solutions in water and heavy water, representative for the behavior of the other HRE ions, 1:1 chloro-complex formation was detected over the concentration range from 0.422–3.224 mol·L−1. The 1:1 chloro-complex in YbCl3(aq) is very weak, diminishing rapidly with dilution and vanishing at a concentration < 0.4 mol·L−1.

K-J polar angular quadrature set for a method of characteristics based on neutrons scattering cross-sections

A novel polar angular quadrature set called the Kim-Jevremovic polar angular quadrature set is derived for the method of characteristics. It is based on neutron anisotropic scattering cross-sections in the Evaluated Nuclear Data File. This new set is implemented within the state-of-the-art neutron transport code AGENT and tested in comparison to MCNP6 as well as to other known quadrature sets for the UO2 unit cells, the well-known C5G7 benchmark, unreflected cylinders of uranyl-fluoride solutions in heavy water, and the University of Utah 100 kWth TRIGA MARK-I reactor core. These comparisons show that the newly proposed polar angular quadrature set provides better agreements than other quadrature sets for the lower order of anisotropic scattering expansions. This paper presents a complete derivation of the Kim-Jevremovic polar angular quadrature set and the analysis for the mentioned bench-mark examples.

Aggregation study in mixture surfactant system TX-100+SDS in heavy water solutions by SANS method

The mixing of amphiphiles in water may lead to the formation of mixed micelles which often present new properties with respect to the pure component solutions [1,2]. The mixture system of classic surfactants SDS (sodium dodecyl sulfate)+TX-100(p-(1,1,3,3- tetramethyl) poly(oxyethylene) (anionic + non-ionic) in heavy water solutions was investigated at temperatures 30°, 50°, 70°C for compositions 1:1, 2:1, 3:1 by the small-angle neutron scattering(SANS) method on spectrometer (‘YuMO’) at the IBR-2 pulsed neutron source at FLNP, JINR in Dubna (Russia). Measurements have covered Q range from 8x10-3 to 0.4 Å-1. From the measured dependence of the scattered intensity on the scattering angle, we derived the size, shape of micelles, aggregation number at various compositions and temperatures. The size of mixed micelle is a weak function of the mixing ratio between the two components.

SANS method study of surfactant mixture system TX-100+C16TAB in heavy water solutions

The mixture system of two classic surfactants cationic and non-ionic – C16TAB (hexadecyltrimethylammonium bromide)+TX-100(p-(1,1,3,3-tetramethyl) poly(oxyethylene) in heavy water solutions was investigated at temperatures 30o, 50o, 70o for compositions 1:1, 2:1, 3:1 by the small-angle neutron scattering(SANS) method on spectrometer (‘YuMO’) at the IBR-2 pulsed neutron source at FLNP, JINR in Dubna (Russia). Measurements have covered Q range from 7x10-3 to 0.4 Å-1. The SANS measurements of aqueous solutions of nonionic / cationic surfactants have shown that the mixed micelles are formed [1-2]. From the measured dependence of the scattered intensity on the scattering angle, we derived the size, shape of micelles, aggregation number at various compositions and temperatures. The size of mixed micelle is a weak function of the mixing ratio between the two components.

Polarized Neutron Reflectometry of Metal Consumption and Passive Film Growth on Nickel Exposed to an Alkaline Deuterium Oxide (D2O) Solution

Electrochemical behavior of Ni in an alkaline heavy water electrolyte was studied using cyclic voltammetry and polarized neutron reflectometry. Delays in the hydrogen and oxygen evolution reactions on Ni electrodes and slower kinetics of the reactions in heavy water compared to light water were observed. However, in both 0.01 mol/L NaOH light and heavy water solutions, Ni oxidation and passive film formation occurred at the same potential with similar passive current densities indicating a minor isotope effect of deuterium on passive film formation and growth. Polarized neutron reflectometry detected a passive film growth coefficient of 11.5 ± 1.1 Å/V. The Ni consumption coefficient was determined to be 7.3 ± 1.5 Å/V. Ni oxidation and passive film growth occurred mostly during the transient period after the applied potential increase but was negligible at the steady state. The electric field strength across the passive film was 8 × 106 V/cm. The Pilling-Bedworth ratio of the passive film during potentiostatic growth was close to the value of NiO grown on bulk Ni. This work demonstrated the capability of neutron reflectometry in the study of passive films on metals and alloys.

The resonant heating of heavy water solutions under the terahertz pulse irradiation

The heating effect of terahertz pulse with various frequencies and intensities on the heavy water solution is investigated using the molecular dynamics simulation. Resonant absorptions are found for both heavy water and light water, but at a different resonant frequency which is about 16 THz for heavy water and 21 THz for light water. This resonant phenomenon can be explained perfectly by the collective rotational modes that may release water molecules from hydrogen bonding. The findings not only illustrate the heating mechanism of heavy water solution under the terahertz pulse irradiation, but also demonstrate a novel difference between light water and heavy water that could have potential applications.

Review on the Determination of Frumkin, Langmuir, and Temkin Adsorption Isotherms at Electrode/Solution Interfaces Using the Phase-Shift Method and Correlation Constants

This review article described the electrochemical Frumkin, Langmuir, and Temkin adsorption isotherms of over-potentially deposited hydrogen (OPD H) and deuterium (OPD D) for the cathodic H2 and D2 evolution reactions (HER, DER) at Pt, Ir, Pt-Ir alloy, Pd, Au, and Re/normal (H2O) and heavy water (D2O) solution interfaces. The Frum-kin, Langmuir, and Temkin adsorption isotherms of intermediates (OPD H, OPD D, etc.) for sequential reactions (HER, DER, etc.) at electrode/solution interfaces are determined using the phase-shift method and correlation constants, which have been suggested and developed by Chun et al. The basic procedure of the phase-shift method, the Frumkin, Lang-muir, and Temkin adsorption isotherms of OPD H and OPD D and related electrode kinetic and thermodynamic param-eters, i.e., the fractional surface coverage (0 ≤ θ ≤ 1) vs. potential (E) behavior (θ vs. E), equilibrium constant (K), interaction parameter (g), standard Gibbs energy (ΔGθ˚) of adsorption, and rate (r) of change of ΔGθ˚ with θ (0 ≤ θ ≤ 1), at the interfaces are briefly interpreted and summarized. The phase-shift method and correlation constants are useful and effective techniques to determine the Frumkin, Langmuir, and Temkin adsorption isotherms and related electrode kinetic and thermodynamic parameters (θ vs. E, K, g, ΔGθ˚, r) at electrode/solution interfaces.

Neutronics analysis of blankets for a hybrid fusion neutron source

Modern challenges of nuclear power concern a potential shortage of nuclear fuel for fission reactors in the case of intensive development of the nuclear industry, insufficient development of economic and safe fast reactors, underutilization of the closed fuel cycle, spent nuclear fuel reprocessing, nuclear power safety and nonproliferation of weapon-grade materials. Expected progress in solving these problems is associated with the development of a hybrid fusion neutron source (FNS) with a subcritical blanket, using the closed nuclear fuel cycle. In this work the capability of hybrid fusion neutron source blankets in the generation of 233U, 239Pu and 3H nuclides, reprocessing of spent nuclear fuel, electricity and heat production are investigated. The basic kinds of blankets are considered. There is a uranium and thorium solid-state blanket, a blanket with the use of heavy water solutions of salts, oxides of uranium and thorium, a molten lead and a molten salt blanket. The structure and geometrical parameters of the blankets, the moderators, and the fertile materials are optimized to obtain the ultimate nuclear fuel yield at the minimal accumulation of radiation toxic wastes. The neutronics comparative analysis of the different blanket models is presented. In the results, the optimal FNS blanket models have been chosen.

Reflection Microspectroscopic Study of Laser Trapping Assembling of Polystyrene Nanoparticles at Air/Solution Interface

We present the formation of a single nanoparticle assembly with periodic array structure induced by laser trapping of 200 nm polystyrene nanoparticles at air/solution interface of the colloidal heavy water solution. Their trapping and assembling behavior is observed by monitoring transmission and backscattering images and measuring reflection spectra under a microscope. Upon the laser irradiation into the solution surface layer, nanoparticles are gathered at and around the focal spot, and eventually a nanoparticle assembly with the size much larger than the focal volume is formed. The assembly gives structural color in visible range under halogen lamp illumination, indicating that constituent nanoparticles are periodically arrayed. Reflection spectra of the assembly show a reflection band, and its peak position is gradually shifted to short wavelength and the bandwidth becomes narrow with time, depending on the distance from the focal spot. After the laser is switched off, red-shift is observed in the ref...

A vibrational spectroscopy study on anserine and its aqueous solutions

In this study based on vibrational spectroscopic measurements and Density Functional Theory (DFT), we aimed for a reliable interpretation of the IR and Raman spectra recorded for anserine in the solid phase and water (H2O) and heavy water (D2O) solutions. Initial DFT calculations at the B3LYP/6-31G(d) searched possible conformers of the anserine zwitterion using a systematic conformational search. The corresponding equilibrium geometrical parameters and vibrational spectral data were determined for each of the stable conformers (in water) by the geometry optimization and hessian calculations performed at the same level of theory using the polarized continuum model (PCM). The same calculations were repeated to determine the most energetically preferred dimer structure for the molecule and the associated geometry, force field and vibrational spectral data. The harmonic force constants obtained from these calculations were scaled by the Scaled Quantum Mechanical Force Field (SQM) method and then used in the calculation of the refined wavenumbers, potential energy distributions, IR and Raman intensities. These refined theoretical data, which confirm the zwitterion structure for anserine in the solid phase or aqueous solvents, revealed the remarkable effects of intermolecular hydrogen bonding on the structural properties and observed IR and Raman spectra of this molecule.

Inventing traditions: interests, parables and nostalgia in the history of nuclear energy

From the late 1960s on, light-water designs dominated the market for nuclear reactors in most Western countries. Up to that point in time, many national governments, scientists and industrialists had favoured the rival concepts of heavy-water and graphite-moderated plants. The article focuses on Sweden and West Germany, where central actors only reluctantly gave up their support for domestically developed heavy-water solutions. Studying new archival material and adopting Hobsbawm and Ranger’s concept of the ‘invention of tradition’, the authors analyze how contemporary actors mobilized both the nation and the past when arguing for plants using natural uranium and heavy water. The paper documents how autarkic arguments were superseded by nostalgic sentiments, and how-subsequently-historians have come to perpetuate apologetic parables like ‘Swedish line’ and ‘tradition’, respectively.

Raman spectroscopic studies and DFT calculations on NaCH3CO2and NaCD3CO2solutions in water and heavy water

Sodium acetate and acetate-d3solutions in water and heavy water were studied using Raman spectroscopy over a wide concentration range from 40–4200 cm−1and DFT calculations were performed on acetate–water clusters.

Neutron Diffraction Study on the Structure of Aqueous LiNO3 Solutions

Neutron diffraction measurements were carried out at 25 °C for aqueous LiNO3 heavy water solutions, (*LiNO3) x (D2O)1−x where x = 0.1, 0.05 and 0.01, in which the 6Li/7Li isotopic ratios were varied. Structural information on intermolecular nearest neighbor Li+···D2O interactions in the extensive concentration range was derived from the first-order difference function, ∆Li(Q), obtained from the difference in scattering cross sections between 6Li- and 7Li-enriched sample solutions. The nearest neighbor Li+···O distance and coordination number for sample solution with x = 0.1 were determined to be r LiO = 1.969 (8) A and n LiO = 4.12 (6), respectively, corresponding to the four-coordinated Li+ ion in the solution. On the other hand, those obtained for the solution with x = 0.01 are r LiO = 2.00 (2) A and n LiO = 6.0 (2), respectively, indicating that hexaaqua Li+ is dominant in the dilute solution. These results clearly indicate that a concentration dependence of the hydration number of Li+ occurs in the aqueous solutions.

Reactivity Impact of 2H and 16O Elastic Scattering Nuclear Data on Critical Systems with Heavy Water

The accuracy of deuterium nuclear data is important for reactor physics simulations of heavy water (D2O) reactors. The elastic neutron scattering cross section data at thermal energies, σs,th, have been observed to have noticeable impact on the reactivity values in simulations of critical systems involving D2O. We discuss how the uncertainties in the thermal scattering cross sections of 2H(n,n)2H and 16O(n,n)16O propagate to the uncertainty of the calculated neutron multiplication factor, keff, in thermal critical assemblies with heavy water neutron moderator/reflector. The method of trial evaluated nuclear data files, in which specific cross sections are individually perturbed, is used to calculate the sensitivity coefficients of keff to the microscopic nuclear data, such as σs(E) characterized by σs,th. Large reactivity differences of up to ≃ 5–10 mk (500–1000 pcm) were observed using 2H and 16O data files with different elastic scattering data in MCNP5 simulations of the LANL HEU heavy-water solution thermal critical experiments included in the ICSBEP handbook.