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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

R&D Progress on Recovery/Recycle of Zirconium from Used Fuel Cladding

There has been significant progress accomplished at Oak Ridge National Laboratory (ORNL) on the development of a dry chlorination process for recovery and purification of zirconium from used nuclear fuel (UNF) cladding by conversion to zirconium tetrachloride, which sublimes to a vapor and is then condensed as a dry salt product, essentially free of fuel and alloy components (impurities). We have accomplished significant progress on developing a chlorination process for removing the zirconium in UNF cladding and purifying the product salt for re-use—possibly in manufacture of new cladding, or at a minimum to meet specifications for disposal as low level waste.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

Deposition of integrated protective material into zirconium cladding for nuclear reactors by high-velocity thermal application

A zirconium alloy nuclear reactor cylindrical cladding has an inner Zr substrate surface, an outer volume of protective material, and an integrated middle volume of zirconium oxide, zirconium and protective material, where the protective material is applied by impaction at a velocity greater than 340 meters/second to provide the integrated middle volume resulting in structural integrity for the cladding.

Mazzoccoli, Jason P.↗
DOE OSTI2015

pH-responsive drug delivery system based on AIE luminogen functionalized layered zirconium phosphate nano-platelets

Aggregation-induced emission (AIE) luminogen, quaternary tetraphenylethene cation (TPEN), was successfully incorporated into layered α-zirconium phosphate (α-ZrP) by using co-precipitation method to form inorganic–organic hybrid materials. The obtained materials show the characteristic hexagonal platelet shape with the interlayer distance did not reveal significant difference compared with pure α-ZrP. In addition, the obtained hybrid materials emit strong blue emission centered at 476 nm in aqueous media due to the electrostatic interactions of TPEN with the anionic framework of α-ZrP, which largely restrict their intramolecular rotation. More importantly, the materials provide a pH dependent release of doxorubicin (DOX), suggesting that AIE luminogen functionalized α-ZrP may be used as an imaging guided and pH-responsive delivery system for targeting therapy. - Graphical abstract: AIE luminogen was successfully incorporated into layered α-zirconium phosphate by a co-precipitation method to form inorganic–organic hybrid materials, showing a pH dependent release of DOX. - Highlights: • AIE luminogen cation was incorporated into layered α-ZrP by co-precipitation method. • The obtained material emits strong blue emission upon UV irradiation. • The material exhibits pH dependent release of DOX. • The AIE functionalized α-ZrP has potential applications in imaging guided therapy.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Gas sorption and transition-metal cation separation with a thienothiophene based zirconium metal–organic framework

The modulated synthesis of the thienothiophene based zirconium metal–organic framework (MOF) material having formula [Zr{sub 6}O{sub 4}(OH){sub 4}(DMTDC){sub 6}]·4.8DMF·10H{sub 2}O (1) (H{sub 2}DMTDC=3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid; DMF=N,N'-dimethylformamide) was carried out by heating a mixture of ZrCl{sub 4}, H{sub 2}DMTDC linker and benzoic acid (used as a modulator) with a molar ratio of 1:1:30 in DMF at 150 °C for 24 h. Systematic investigations have been performed in order to realize the effect of ZrCl{sub 4}/benzoic acid molar ratio on the crystallinity of the material. The activation (i.e., the removal of the guest solvent molecules from the pores) of as-synthesized compound was achieved by stirring it with methanol and subsequently heating under vacuum. A combination of X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermogravimetric (TG) and elemental analysis was used to examine the phase purity of the as-synthesized and thermally activated 1. The material displays high thermal stability up to 310 °C in an air atmosphere. As revealed from the XRD measurements, the compound retains its crystallinity when treated with water, acetic acid and 1 M HCl solutions. The N{sub 2} and CO{sub 2} sorption analyses suggest that the material possesses remarkably high microporosity (S{sub BET}=1236 m{sup 2} g{sup −1}; CO{sub 2} uptake=3.5 mmol g{sup −1} at 1 bar and 0 °C). The compound also shows selective adsorption behavior for Cu{sup 2+} over Co{sup 2+} and Ni{sup 2+} ions. - Graphical abstract: Selective transition-metal cation adsorption by a thienothiophene based zirconium metal–organic framework material. - Highlights: • The modulated synthesis of a thienothiophene based Zr(IV) MOF has been described. • Effect of metal salt/modulator ratio on the crystallinity was thoroughly studied. • The compound showed high thermal and physiochemical stability. • N{sub 2} and CO{sub 2} sorption experiments revealed significantly high microporosity. • The material showed high adsorption selectivity for Cu{sup 2+} over Co{sup 2+} and Ni{sup 2+} ions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Influence of frequency on the structure of zirconium oxide coatings deposited from aqueous electrolytes under microplasma oxidation

The work describes the microplasma oxidation (MPO) of zirconium surface resulting in the formation of zirconium oxide Zr-Al-Nb-O. We have used novel power supply to deposit oxide ceramic coatings by MPO and studied the effect of current density on the phase structure of oxide ceramic coatings. The size of microcracks in the coatings was determined at different frequencies. We have also used EVO50c scanning election microscope with an attachment for elemental analysis to study the morphology and elemental composition of oxide ceramic coating. In addition, we have established the influence of the frequency on the phase composition of the coating: at the frequency of 2500 Hz, the fraction of monoclinic phase was 18%, while the fraction of tetragonal phase amounted to 72%. The oxide ceramic coating produced at 250 Hz contained 38% of monoclinic phase and 62% of tetragonal phase; in addition, it had no buildups and craters.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Growth, structure, and high temperature stability of zirconium diboride thin films

Morphologically stable, electrically conductive thin films are required for emerging harsh environment sensors that can operate at temperatures above 1000 °C. Zirconium diboride (ZrB{sub 2}) is an ultrahigh temperature ceramic with a melting temperature greater than 3200 °C and in bulk form has an electrical conductivity of ∼10{sup 7 }S/m. Thin films of varying Zr:B ratio have been deposited on sapphire substrates by electron beam coevaporation from elemental sources. An appropriate ratio of the elemental fluxes was determined to produce nearly stoichiometric ZrB{sub 2} thin films. Films deposited at ambient substrate temperatures are amorphous as measured by x-ray diffraction, while films grown at 600 °C show textured ZrB{sub 2} nanocrystallites in an amorphous matrix, regardless of composition. When annealed in ultrahigh vacuum at 800 and 1000 °C for 1 h, nanocrystalline films show further grain growth with a 〈101{sup ¯}0〉 ZrB{sub 2} preferred orientation normal to the substrate, while the low nucleation rate in the amorphous films inhibits the formation of any substantial grains. Film conductivity ranges between 0.13 and 6.3 × 10{sup 5 }S/m, increasing with zirconium content and crystallite grain size. Besides grain growth, no micron-scale structural or morphological changes were observed with annealing, suggesting that ZrB{sub 2} films can act as stable electrodes in high temperature environments.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Effect of precipitates in oxide film on hydrogen pick-up of zirconium alloys

In this study, we examined the effect of alloying elements on hydrogen pick-up. The alloying elements of Fe, Cr, and Ni form precipitates in Zircaloy because of their low dissolvability in Zirconium. The precipitates in oxide film are presumed to play an important role in the hydrogen pick-up process because oxide film is a pathway of hydrogen entry. A corrosion test was performed in pure water at 561 K, and the relation between the additive elements and the hydrogen pick-up was estimated by using Zircaloy-2 and Zircaloy-4. The behavior of precipitates in oxide film was estimated using TEM observation and molecular dynamic simulation. The results show that the un-oxidized precipitates had a tendency to substitute for the oxidized precipitates with distance from the metal-oxide film boundary. Additionally, precipitates containing a high concentration of oxygen were observed. The oxidation of the precipitates was confirmed. It was also shown that the Fe/Cr fraction of precipitates had a tendency to decrease with distance from the metal-oxide film boundary. It was confirmed that the diffusion coefficients of H{sup +} in the iron- or chromium-containing ZrO{sub 2} are smaller than those of the pure ZrO{sub 2} by molecular dynamics simulation. These results lead to the conclusion that the diffusion of Cr and Fe in oxide film contributes to the control of hydrogen pick-up on zirconium alloys as does the oxidation of precipitates.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Investigation on Reaction Probabilities for Cyclic Voltammetry of Zirconium in LiCl-KCl Eutectic Molten Salt via Reverse-Engineering Method

This work focuses on a reverse-engineering program design for the cyclic voltammetry (CV) method to help illustrating, enhancing, and providing robustness in detection probability of the reactions during an electrorefining process. Analyzing the reactions from CV plots for 1.07, 2.49, and 4.98 wt% of zirconium chloride (ZrCl{sub 4}) in a LiCl-KCl molten salt at 773 K under different scan rates from Hoover's study has been accomplished. The results provide the current (Amp) versus potential (V) to investigate the optimum probability of the reactions at each peak. All simulations have been done through the commercial software MATLAB by using various experimental values existing in the literature as a first guess (e.g., the diffusion coefficients, and formal potentials). Preliminary results indicate that the zirconium reactions at each peak from cathodic to anodic side for 1.07 wt% are as followed: combination of Zr{sup +2}/Zr and Zr{sup +4}/ Zr{sup +2} at approximately -1.15 V, Zr{sup +2}/Zr at -1.5 V, Zr{sup +4}/Zr at -1.85 V, 70% Zr/Zr{sup +4} and 30% Zr/Zr{sup +2} at -0.5 V, and Zr{sup +2}/ Zr{sup +4} at - 0.25 V. These mentioned peaks are similar for 2.49 wt% at different voltages. In addition, the highest anodic peak for 4.98 wt% is found to be a combination of 30% Zr/Zr{sup +4} and 70% Zr/Zr{sup +2}. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

Modification and intercalation of layered zirconium phosphates: a solid-state NMR monitoring

Several layered zirconium phosphates treated with Zr(IV) ions, modified by monomethoxy-polyethyleneglycol-monophosphate and intercalated with doxorubicin hydrochloride have been studied by solid-state MAS NMR techniques. The organic components of the phosphates have been characterized by the 13 C{ 1 H} CP MAS NMR spectra compared with those of initial compounds. The multinuclear NMR monitoring has provided to establish structure and covalent attachment of organic/inorganic moieties to the surface and interlayer spaces of the phosphates. Finally, the MAS NMR experiments including kinetics of proton-phosphorus cross polarization have resulted in an unusual structure of zirconium phosphate 6 combining decoration of the phosphate surface by polymer units and their partial intercalation into the interlayer space.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Unexpected structural/motional mode of water intercalated into an α-crystalline zirconium phosphate deduced by 31 P and 2 H solid-state MAS NMR spectra

Here, in developing the approach to understanding dynamics of intercalates in layered materials, crystalline-layered zirconium phosphate Zr (HPO 4 ) 2 ·0.35D2O has been prepared and characterized by the 1 H, 31 P, and 2 H solid-state MAS NMR spectra, including 31 P and 2 H T 1 measurements. At temperatures >253 K, the intercalated water shows two spectrally-distinguished deuterons unprecedentedly with different DQCC's and 2 H T 1 times, one of which is hydrogen bonded. The collected data allowed to identify an unexpected bonding/dynamic mode of water molecules, which experience fast rotation around the hydrogen bond, formed with a zirconium-coordinated oxygen. The low-temperature 2 H MAS NMR experiments have demonstrated the presence of additional hydrogen bond P—(H)O˙˙˙ DO, population of which grows on cooling to 195 K corresponding to the doubly hydrogen-bonded immobile water molecule.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Elucidating structure and dynamics of crystalline α-zirconium phosphates intercalated with water and methanol by multinuclear solid-state MAS NMR: A comprehensive NMR approach

Solid-state NMR experiments on 2 H, 31 P, 13 C, and 1 H nuclei, including 31 P T 1 , 1 H T 1 , and 1 H T 1ρ measurements, as well as on the kinetics of proton-phosphorus cross-polarization have been performed to characterize the crystalline and amorphous α-zirconium phosphates, which were intercalated with D 2 O and/or CD 3 OD. The 13 C{ 1 H} CP MAS NMR experiment performed for compound 1-CD 3 OD (Zr (HPO 4 ) 2 .0.2CD 3 OD) with carbon cross-polarization via protons of phosphate groups has provided a prove that the methanol was intercalated into the interlayer spaces of this compound. The variable-temperature 2 H solid-echo MAS NMR spectra of intercalated compounds demonstrated that the methanol molecules, in contrast to the mobile water, were immobile, keeping, however, free CD 3 rotations around the C 3 -axis. It has been demonstrated that the intercalated species, D 2 O and CD 3 OD, do not affect the high-frequency motions of the phosphate groups. By utilizing local structural models that satisfy the constraints of the experimental data, it has been suggested that the immobile methanol molecules are located in the cavity between two neighboring layers of the zirconium phosphates. Here, the present work illustrates the reliable criteria in a comprehensive NMR approach to structural and dynamic studies of such systems.

1H↗
DOE OSTI2018

Dimensional Stability of the Structural Parts of VVER-1000 FA Made of E-635 Zirconium Alloy

The dependence of dimensional changes occurring in the structural parts made of E-635 zirconium alloy on the metallurgical and operational factors as a result of thermal creep, radiation growth, and radiation creep was studied. Tests close to operating conditions showed high resistance to radiation growth and thermal and radiation creep of the structural parts of VVER-1000 fuel assemblies made of E-635 zirconium alloy. Parts with greater resistance to creep without irradiation also possess high resistance to creep in the presence of irradiation. However, in-reactor creep can be almost 10 times greater than creep with no irradiation.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

Study of Thermomechanical Behavior of Zirconium-0.3 Tin Alloy

Zirconium-based alloys are used in the manufacturing of nuclear fuel tubes. These tubes need to be clad with zirconium-tin (Zr-0.3 wt.% Sn) alloy to enhance the lives of tubes. Manufacturing of such clad tubes is a challenging task, due to work hardening and dynamic softening phenomenon. In this study, hot deformation behavior of Zr-0.3Sn alloy is investigated at different temperatures and strain rates. It is found that fully recrystallized microstructure can be obtained by working at around 900 °C and high strain rate of 10 s{sup −1}. Further, constitutive equations are developed for the entire domain of deformation range and fitted into standard FEM-based simulation model for extrusion. The simulation results are validated with experimental data. The difference in flow stresses values obtained from numerical and experimental methods was around 14%.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Synthesis of nanograined zirconium diboride microsphere powder feedstock via emulsification of suspensions

Ceramic nanograined materials have desirable characteristics compared to their macroparticle counterparts but are rarely used in industrial applications due to issues with poor handleability and health hazards. Due to interparticle forces that become more dominant as the particle size decreases, it is difficult to use nanomaterials to fill dies, spread on surfaces, or flow through hoppers found in various manufacturing processes. In this work, we report a scalable gelcasting solution and unique emulsification process to create microspheres composed of nanoscale powders to enhance the flowability and handleability of nanomaterials. The gelcasting solution and emulsification process can be used with any nanoparticle composition that can be suspended in a liquid phase. This paper reports the effects of various parameters on zirconium diboride microsphere formation, such as surfactant content and mixing conditions. The microspheres maintain the nano-scale characteristics of the powder but improve its flowability by using cross-linked polyvinyl alcohol to combine irregularly shaped zirconium diboride nanoparticles with a particle diameter of 60 nm into larger spherical particles with a d 50 ~25 μm. This hierarchical feedstock engineering design combine the positive characteristics of materials across both length scales and improve the flowability of the feedstock from a Hausner Ratio of 1.56 to 1.19. The materials produced using this technique can be used in thermal plasma spray, die filling for hot pressing or spark plasma sintering, and binder jet printing applications.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Measurement of leakage neutron spectra for zirconium with D-T neutrons and validation of evaluated nuclear data

Integral neutronics experiments have been a powerful tool and method for examining the reliability of evaluated nuclear data. In the present paper, the accuracy of evaluated nuclear data for Zirconium has been validated by comparing measured leakage neutron spectra with calculated ones. Leakage neutron spectra from the irradiation of D-T neutrons on Zirconium samples were experimentally measured at 60° and 120° by using a time-of-flight method. Theoretical calculations are carried out by Monte Carlo neutron transport code MCNP-4C with evaluated nuclear data of the ENDF/B-VII.0, ENDF/B-VIII.0, JENDL-4.0 and CENDL-3.1 libraries. From the comparisons, it is found that the calculations with JENDL-4.0 gives better agreements with the experiments at 60° while a large discrepancies are observed in the 4–13.5 MeV energy range at 120°. However, the calculated spectra using the data from ENDF/B-VII.0, ENDF/B-VIII.0 and CENDL-3.1 libraries showed some discrepancies with the measured ones, especially caused by the difference of the elastic and inelastic angular distributions and the secondary neutron energy distributions in the continuum inelastic scattering.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2018

Quantifying the stress state in the vicinity of a δ-hydride in α-zirconium

In zirconium alloys, precipitation of a hydride generally introduces internal stresses in the surrounding matrix. This study aims at understanding the role of internal stresses on the formation, growth and arrangement of δ-hydrides in α-zirconium. To this end, a Fast Fourier Transform based discrete dislocation dynamics technique is used to quantify both internal stresses induced during the formation of a hydride and the relief of the internal stresses by dislocation nucleation from the hydride-matrix interface. Overall, this work reveals that stress relaxation is localized in very small regions around the δ-hydride ( 300 nm). Further, it is proposed that the dislocations nucleated from the hydride-matrix interface could act as loci for the nucleation of new hydrides, thereby rationalizing experimentally observed hydride stacks. Finally, quantifying the stress relaxation resulting from dislocation nucleation reveals that diagonal components of the internal stress inside the hydride remain very high, i.e., >3.0 GPa. We find that this suggests that additional dissipative processes, intrinsic to the hydride, are necessary to diminish the aforementioned internal stress.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Irradiation-induced amorphization in the zirconium suboxide on Zr-0.5Nb alloys

For the first time, the observation of irradiation-induced amorphization of the zirconium suboxide formed during aqueous corrosion of Zr-0.5Nb alloys is discussed. High-resolution transmission electron microscopy results reveal amorphization of the hexagonal-ZrO suboxide under heavy ion irradiation at cryogenic temperatures. This irradiation-induced amorphization behaviour is discussed in relation to the arrangement of oxygen interstitials and the formation of stable superlattices. The sensitivity of the suboxide to irradiation damage can lead to phase changes and the accumulation of defects near the oxide/metal interface, which needs to be considered in the development of mechanistic models addressing radiation-assisted acceleration of corrosion rates in zirconium alloys.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Production of 28 μm zirconium carbide kernels using the internal gelation process and microfluidics

Studies using internal gelation and microfluidics have shown that the production of sintered spheres with diameters below 200 mm is possible. The addition of carbon can be problematic because of slow flow rates (100 mL/min) and long run times (4 h). However, we report a solution of dispersed carbon, Cabot’s TPX-101, was successfully used with solutions of zirconyl nitrate, urea, and hexamethylenetetramine to make zirconium microspheres with carbon. A simple carbothermic reduction using a maximum temperature of 2073 K and ultrahigh purity argon produced zirconium carbide kernels with an average diameter of 28 mm and a standard deviation of 2.3 mm.

36 MATERIALS SCIENCE↗