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At least 1,387 records · Page 77
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

NSTX-U liquid metal core-edge facility (LMCE)

NSTX-U/LMCE will provide a unique and world-leading research facility to address the primary challenge to delivering economic and timely magnetic fusion energy, namely the need to develop a power and particle exhaust and first-wall system that can withstand very high edge heat fluxes, maximize energy confinement, and avoid the production of large masses of solid eroded first-wall material. The NSTX-U/LMCE facility will assess the ability of liquid metals (LMs) – especially liquid lithium – to provide a new boundary condition for magnetic fusion systems, to extend the lifetime of the plasma facing components (PFCs) and improve core plasma confinement. Such capability is needed to establish the basis for next-step fusion facilities including fusion pilot plants, and to maintain U.S. world leadership in core-edge integration research. NSTX-U/LMCE will leverage the ability to generate very high divertor perpendicular heat flux q⊥ ~ 100MW/m 2 , extensive diagnostics, and liquid-metal-applicable infrastructure of NSTX-U. NSTX-U/LMCE will provide access to a high-confinement plasma core with majority self-driven plasma current, the flexibility to test a range of liquid metal divertor concepts, access to a range of separatrix collisionalities (from high to very low), and the ability to controllably vary the first-wall temperature to vary the plasma- wall interaction physics on liquid lithium components. Further, NSTX-U/LMCE will utilize more reactor-relevant high-Z refractory-metal PFC substrates. With these capabilities the NSTX-U/LMCE facility will explore the full continuum of core-edge solutions ranging from high core radiated power, to conditions with radiative losses concentrated in the scrape-off layer (SOL), and ultimately low recycling conditions. The low collisionality SOL that may be accessible in the low recycling regime is relatively unexplored and will require a kinetic treatment of the edge, which can be addressed theoretically, and with experiments in LTX-β. Additional smaller-scale preparatory R&D facilities will be required to reduce the risk of premature technical/engineering failure of liquid metal systems implemented in NSTX-U. The NSTX-U/LMCE facility aligns very well with recommendations in the FESAC Long-Range Plan and NASEM Pilot Plant reports and the Bold Decadal Vision, will be unique in the world program throughout the next decade, and is garnering private company interest in utilizing NSTX-U/LMCE for development of LM PFCs.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

WASTE TREATMENT PLANT (WTP) LIQUID EFFLUENT TREATABILITY EVALUATION (SEPTEMBER 2004)

A forecast of the radioactive, dangerous liquid effluents expected to be produced by the Waste Treatment Plant (WTP) was provided by Bechtel National, Inc. (BNI 2004). The forecast represents the liquid effluents generated from the processing of Tank Farm waste through the end-of-mission for the WTP. The WTP forecast is provided in the Appendices. The WTP liquid effluents will be stored, treated, and disposed of in the Liquid Effluent Retention Facility (LERF) and the Effluent Treatment Facility (ETF). Both facilities are located in the 200 East Area and are operated by Fluor Hanford, Inc. (FH) for the US. Department of Energy (DOE). The treatability of the WTP liquid effluents in the LERF/ETF was evaluated. The evaluation was conducted by comparing the forecast to the LERF/ETF treatability envelope (Aromi 1997), which provides information on the items which determine if a liquid effluent is acceptable for receipt and treatment at the LERF/ETF. The format of the evaluation corresponds directly to the outline of the treatability envelope document. Except where noted, the maximum annual average concentrations over the range of the 27 year forecast was evaluated against the treatability envelope. This is an acceptable approach because the volume capacity in the LERF Basin will equalize the minimum and maximum peaks. Background information on the LERF/ETF design basis is provided in the treatability envelope document.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Short- and Intermediate-Range Structure and Dynamics of Fe-Ni-C Liquid Under Compression

Properties of liquid Fe alloys under high-pressure conditions are crucial for understanding the composition, thermal state, and dynamics of Earth’s core. Experiments on such liquids, however, are often performed under pressures far below those of the outer core, necessitating long extrapolations of experimental results to core conditions. Such estimates can be complicated by light elements possibly forming pressure-dependent molecular clusters that can significantly affect the physical properties of liquids as core conditions are approached. First-principles molecular dynamics simulations were employed to compute the properties of an Fe-Ni-C liquid with a composition of Fe 3.7 Ni 0.37 C at 1673 K and pressures from 0 to 67 GPa to benchmark computational methods on pressure effects on the structure and properties of the liquid relative to low pressure experimental results. The short-range structure is manifested by the coordination number (CN) of Fe/Ni-Fe/Ni being around 12, indicative of a nearly close-packed structure in the pressure range, and the CN of C-Fe/Ni gradual increasing from 6.5 to 8.5, indicative of an approximately octahedral to cubic transition as pressure increases. The Fe/Ni-Fe/Ni bond distance, however, is found to be 10 times more compressible than the C-Fe/Ni distance. The intermediate-range structure of Fe/Ni-Fe/Ni and C-Fe/Ni subsystems, described by a partial configurationally decomposed distribution function, undergoes substantial changes, characterized by a significant increase of the number of polyhedra that share 3 atoms with each other. Such dense configurations are related to an increased bulk modulus, decreased diffusion coefficient, decreased activation volume for diffusion, and increased shear viscosity. Reproducing the experimental observations at low pressures provides important support for modeling the liquid under the conditions relevant to the outer core.

58 GEOSCIENCES↗
DOE OSTI2022

Development of Explainable Data-Driven Turbulence Models with Application to Liquid Fuel Nuclear Reactors

Liquid fuel nuclear reactors offer innovative possibilities in terms of nuclear reactor designs and passive safety systems. Molten Salts Reactors (MSRs) with a fast spectrum are a particular type of these reactors using liquid fuel. MSFRs often involve large open cavities in their core in which the liquid fuel circulates at a high speed to transport the heat generated by the nuclear reactions into the heat exchangers. This high-speed flow yields a turbulent field with large Reynolds numbers in the reactor core. Since the nuclear power, the neutron precursor’s transport and the thermal exchanges are strongly coupled in the MSFR’s core cavity, having accurate turbulent models for the liquid fuel flow is necessary to avoid introducing significant errors in the numerical simulations of these reactors. Nonetheless, high-accuracy simulations of the turbulent flow field in the reactor cavity of these reactors are usually prohibitively expensive in terms of computational resources, especially when performing multiphysics numerical calculations. Therefore, in this work, we propose a novel method using a modified genetic algorithm to optimize the calculation of the Reynolds Shear Stress Tensor (RST) used for turbulence modeling. The proposed optimization methodology is particularly suitable for advanced liquid fuel reactors such as the MSFRs since it allows the development of high-accuracy but still low-computational-cost turbulence models for the liquid fuel. We demonstrate the applicability of this approach by developing high accuracy Reynolds-Averaged Navier–Stokes (RANS) models (averaged flow error less than 5%) for a low and a large aspect ratio in a Backward-Facing Step (BFS) section particularly challenging for RANS models. The newly developed turbulence models better capture the flow field after the boundary layer tipping, over the extent of the recirculation bubble, and near the boundary layer reattachment region in both BFS configurations. The main reason for these improvements is that the developed models better capture the flow field turbulent anisotropy in the bulk region of the BFS. Then, we illustrate the interest in using this turbulence modeling approach for the case of an MSFR by quantifying the impact of the turbulence modeling on the reactor key parameters.

42 ENGINEERING↗
DOE OSTI2022

Liquid Core Detection and Strand Condition Monitoring in a Continuous Caster Using Optical Fiber

Real-time monitoring of the liquid core position during the continuous casting of steel has been demonstrated using low-cost distributed optical-fiber-based strain sensors. These sensors were installed on the containment roll support structures in the segments of a production continuous caster to detect the position of the solid–liquid interface and monitor the strand condition during the continuous casting. Distributed Fiber Bragg Grating sensors (FBGs) were used in this work to monitor strain at six roll positions in the caster. The sensor performance was first validated by comparing optical strain measurements with conventional strain gauge measurements in the lab. Next, optical strain measurements were performed on an isolated caster segment in a segment maintenance facility using hydraulic jacks to simulate the presence of a liquid core under the roll. Finally, the sensors were evaluated during caster operation. The sensors successfully detected the load increase associated with the presence of a liquid core under each instrumented roll location. Incidents of bulging and roll eccentricity were also detected using frequency analysis of the optical strain signal. The liquid core position measurements were compared using predictions from computer models (digital twins) in use at the production site. The measurements were in good agreement with the model predictions, with a few exceptions. Under certain transient caster operating conditions, such as spraying practice changes and SEN exchanges, the model predictions deviated slightly from the liquid core position determined from strain measurements.

47 OTHER INSTRUMENTATION↗
DOE OSTI2016

Multiphysics analysis of liquid metal annular linear induction pumps: A project overview

Liquid metal-cooled fission reactors are both moderated and cooled by a liquid metal solution. These reactors are typically very compact and they can be used in regular electric power production, for naval and space propulsion systems or in fission surface power systems for planetary exploration. The coupling between the electromagnetics and thermo-fluid mechanical phenomena observed in liquid metal thermo-magnetic systems for nuclear and space applications gives rise to complex engineering magnetohydrodynamics and numerical problems. It is known that electromagnetic pumps have a number of advantages over rotating mechanisms: absence of moving parts, low noise and vibration level, simplicity of flow rate regulation, easy maintenance and so on. However, while developing annular linear induction pumps, we are faced with a significant problem of magnetohydrodynamic instability arising in the device. The complex flow behavior in this type of devices includes a time-varying Lorentz force and pressure pulsation due to the time-varying electromagnetic fields and the induced convective currents that originates from the liquid metal flow, leading to instability problems along the device geometry. The determinations of the geometry and electrical configuration of liquid metal thermo-magnetic devices give rise to a complex inverse magnetohydrodynamic field problem were techniques for global optimization should be used, magnetohydrodynamics instabilities understood –or quantified- and multiphysics models developed and analyzed. Lastly, we present a project overview as well as a few computational models developed to study liquid metal annular linear induction pumps using first principles and the a few results of our multi-physics analysis.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Accurate Optical Constants for Liquids in the Near-Infrared: Improved Methods for Obtaining the n and k Constants from 1 to 4 Microns

Other than open bodies of water, bulk liquids are rarely encountered in the environment. Rather, liquids are typically found as aerosols, liquid droplets, or liquid layers on sundry substrates: glass, concrete, metals, etc. The layers can be of varying thicknesses, from micron-level to millimeter thick deposits. The infrared (IR) reflectance spectra of such deposits vary greatly, approximating the bulk reflectance for thicker deposits and for thinner layers on reflective surfaces, producing “transflectance” spectra that more closely replicate simple transmission of the IR light twice traversing the absorptive medium. Rather than recording large numbers of such spectra to serve as endmembers of a spectral reflectance library, we have recognized that the spectra can be modeled so long as the complex optical constants n(?) and k(?) are known as a function of frequency, ?. Here n is the real (dispersion) part and k is the imaginary (absorption) component of the complex index of refraction. However, in many cases the bands in the longwave IR (7 to 13 µm) can become saturated, and better signal-to-noise and specificity can be realized at shorter wavelengths. In earlier studies, we obtained the n/k values from 1.28 to 25 µm for a series of liquids, but are now expanding those measurements to include additional liquid species and extending the spectral range to lower wavelengths. In this paper we describe the methodologies for compiling and fusing the two data sets collected to provide better and more complete spectral coverage from 1 to 25 µm (10,000 to 400 cm-1). The broad spectral range means that one needs to account for both strong and weak spectral features, all of which can be useful for detection, depending on the scenario. To account for the large dynamic range, both long and short path length transmission cells are required for accurate measurements.

optical constants, refractive index, liquids, mid ↗
DOE OSTI2019

Investigative Studies toward the Extraction and Recovery of Praseodymium From Ionic Liquids Using Supercritical Carbon Dioxide

Recycle of rare earth elements requires the extraction and recovery of these metals from consumer products such as rechargeable batteries, electric motor magnets, and aircraft engines once the rare earths have been oxidatively dissolved. One approach to this is to combine the metal extraction and recovery steps into a continuous process. Such a scheme would involve direct-dissolution and ligand-assisted supercritical fluid extraction of the metal, followed by deposition of the extracted metal complex into an ionic liquid where it can be electrochemically reduced to its metallic state. Whereas supercritical fluid extraction of rare earth metals has been recently studied, deposition of rare earth metal-ligand complexes into an ionic liquid is not well known for many rare earth metal-ligand systems. In these studies we measured the solubility of several Praseodymium complexes in scCO2. We also measured the solubility of the Praseodymium complexes in ionic liquids with different physical properties of interest including polarizability, viscosity, and conductivity. The ionic liquids studied are from the pyrrolidinium family and include n-butyl-n-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPy TFSI). Upon completion of these experiments, we added an additional modifier to the ionic liquid solution in the form of a chelating agent and carbon dioxide. Overall, the additions of the various chelating agents and BMPy TFSI result in large changes to viscosity, conductivity, and metal complexation properties of the solutions. Here we report the results of our findings and discuss the possibility of tuning the extractive and reductive properties of the solutions by picking ionic liquids and chelating agents with physical properties conducive to the desired metal recovery scheme.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Characterization of the liquid sodium spray generated by a pipework hole

Due to its advantageous thermodynamic characteristics at high temperature (550 deg. C), liquid sodium is the main candidate to be the cooling fluid for Generation TV nuclear reactors SFR (Sodium-cooled Fast Reactors). Now, sodium reacts very violently, both with the water and the oxygen of the air. Only few data were known about the liquid sodium behaviour when spread in the environment through micro defects. These are often present in a cooling circuit in welded or sealed joints and more rarely in the pipes. Micro defects, on the other hand, can be also generated in a cooling circuit because of the vibrations always present in a circuit into which a fluid runs. A new set-up, named LISOF, was built for testing high temperature liquid sodium when passing through micro defects and generating sprays or jets. Sprays and jets were generated by means of nozzles embedding sub milli-metric holes the diameter of which was: 0.2 mm, 0.4 mm, 0.5 mm. Tests were performed by pressurizing liquid sodium (550 deg. C) at: 3, 6 and 9 barg. Normal and high speed cinematography were used for the direct observation of the liquid sodium sprays while Phase Doppler Interferometry was used for the measurement of the droplets characteristics and velocity. Tests concerning the behaviour of the high temperature liquid sodium firing in air or in contact with the cement cover applied to a scaled down core catcher simulacrum were also performed. The paper presents the built set-up and the collected results. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2018

Immobilization of Organic Liquid Radioactive Waste (LWR) in a Sulfur Composite Matrix at the BN-350 Fast Neutron Reactor Site, Kazakhstan - 18031

The immobilization treatment and final disposition of all forms of organic radioactive liquids, such as pump oil, spent solvent, tri-butyl-phosphate (TBP) and scintillation fluids, remain a significant challenge for nuclear waste generators and national regulators. The majority of nuclear nations have instituted regulations that require some form of encapsulation of treated organic liquid, notwithstanding LLW organic liquids that can be safely incinerated. In most cases cement is the designated material for encapsulation; however, cement can pose certain problems with the containment of treated organic liquids. In 2013, with funding from the U.S. Department of Energy - National Nuclear Security Administration through its Global Initiative for Proliferation Prevention Program (GIPP), a proven U.S. technology for the treatment of radioactive organic liquids was introduced at the BN-350 fast neutron reactor facility in Aktau, Kazakhstan. As the facility was undergoing full decommissioning, one hundred and sixty cubic meters of contaminated pump oil (including Cs-137, Sr-90 and U-235/238) contained in large above ground tanks had to be treated for final disposal. As a result of the research conducted over a two-year period, a new 2-step treatment process was invented by combining the U.S. solidification technology with a newly developed inorganic filler and molecular sulfur, referred to as radiation-resistant composite (RRC) to fully encapsulate the waste oil. The outcome of extensive test program indicates that the final form can reach up to 60 wt.% with a compressive strength of about 100 kg/cm{sup 2}. Preliminary conclusions indicate that RRC outperforms cement as an encapsulation form for final waste treatment which meets U.S. Nuclear Regulatory requirements for final disposal. This paper examines the preliminary experimental work that was conducted in Kazakhstan with the U.S. polymer technology and radioactive pump oil, and the subsequent secondary process of combining the solidified material into a homogeneous final form utilizing RRC. Topics covered in the paper include: - Kazakhstan's regulatory requirements for attaining an achievable waste form for acceptance, which led to the RRC invention; - Technical objectives for the application of polymer technology and RRC materials to radioactive liquid waste; - Polymer solidification with radioactive oil and the result; step one of the RRC process; - Description of RRC materials, their origin and chemical characteristics; - Process of combining the solidified polymer mass with RRC materials into a solid, homogeneous matrix; step two of the RRC process; - Experimental results including leaching data, waste loading estimates and heat process calculations to create the matrix; - Cost advantages of the RRC process over cementation; - Limitations of the RRC process; - Next steps to verify conformance of the RRC technology to the U.S. requirements. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Molecular Brush Surfactants: Versatile Emulsifiers for Stabilizing and Structuring Liquids

Using amphiphilic molecular brushes to stabilize emulsions usually requires the synthesis of specific side chains, which can be a time-consuming and difficult challenge to meet. By taking advantage of the electrostatic interactions between water-soluble molecular brushes and oil-soluble oligomeric ligands, here the in situ formation, assembly and jamming of molecular brush surfactants (MBSs) at the oil-water interface is described. With MBSs, stable emulsions including o/w, w/o and o/w/o can be easily prepared by varying the molar ratios of the molecular brushes to the ligands. Moreover, when jammed, the binding energy of MBSs at the interface is sufficiently strong to allow the stabilization of liquids in nonequilibrium shapes, i.e., structuring liquids, producing an elastic film at the interface with exceptional mechanical properties. These structured liquids have numerous potential applications, including chemical biphasic reactions, liquid electronics, and all-liquid biomimetic system.

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

Continuous recovery of high-purity Kraft lignin from black liquor via simultaneous, liquid-phase acidification and purification

Here, a key advantage of the Sequential Liquid-Lignin Recovery and Purification (SLRP) process for the recovery of lignin from Kraft black liquor is the precipitation of a solvated, “liquid-lignin” phase (vs. the typical solid) during the CO 2 acidification step. Here, we have discovered that this lignin can also be maintained in a solvated state during the H 2 SO 4 acidification step if aqueous acetic acid from the Aqueous Lignin Purification with Hot Agents (ALPHA) process is incorporated into the H 2 SO 4 solution. As the liquid-lignin is converted from its salt form at pH = 9.5 to its acid form at pH = 2.5, the lignin initially solvated with water becomes solvated and thus liquefied with the organic–water solution. Maintaining the lignin in a solvated liquid state has two advantages: (1) the entire SLRP + ALPHA process, from starting black liquor to final lignin product, can be operated continuously; and (2) mass transfer of metals impurities out of the liquid-lignin phase is significantly enhanced, resulting in both a cleaner Kraft lignin product (~2000 ppm Na and 0.5-1.0 % ash) and reduced water washing.

09 BIOMASS FUELS↗
DOE OSTI2023

An anomalous structure disordering in Zr–Cu–Ag supercooled glass-forming liquids

An anomalous ordering-to-disordering transition in a Zr–Cu–Ag supercooled glass-forming liquid has been revealed by in situ high-energy x-ray diffraction. Upon heating, the supercooled liquid exhibits a structural crossover at T c = 716 K, evident by the change in statistical characteristics of the first sharp diffraction peak. When annealed in the vicinity of T c , the supercooled liquid first relaxes from its initial state to a denser and more ordered state. Subsequently, it becomes disordered at the medium-range scale with a slowing down of densification, as demonstrated by the broadening of the first sharp diffraction peak and a decrease in the peak intensities of the higher atomic shells in the reduced pair distribution function. Finally, a scenario for the evolution of less correlated locally favored clusters in the liquid–liquid phase transition is discussed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Enzymatic degradation of liquid droplets of DNA is modulated near the phase boundary

Significance Biomolecules, such as proteins or nucleic acids, can condense into liquid droplets whose biological or technological function depends on interactions with other solutes. We explore such interactions using a system of self-assembled DNA particles that forms liquid droplets which are degraded by an active solute, a restriction enzyme. We find that enzymes are able to penetrate the droplets when the liquid is poised near the phase boundary, enhancing the degradation rate and, in certain cases, causing internal bubbling. These results point to a complex interplay of phase stability and solute transport in liquid–liquid phase-separating macromolecular systems.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Engineering Permanent Porosity into Liquids

The possibility of engineering well-defined pores into liquid materials is fascinating from both a conceptual and an applications point of view. Although the concept of porous liquids was proposed in 2007, these materials had remained hypothetical due to the technical challenges associated with their synthesis. Over the past five years, however, reports of the successful construction of porous liquids based on existing porous scaffolds, such as coordination cages, organic cages, metal–organic frameworks, porous carbons, zeolites, and porous polymers, have started to emerge. Here, the focus is on these early reports of porous liquids as prototypes in the field, classified according to the previously defined types of porous liquids. Particular attention will be paid to design strategies and structure–property relationships. Porous liquids have already exhibited promising applications in gas storage, transportation, and chemical separations. Furthermore, they show great potential for use in the chemical industry. The challenges of preparation, scale-up, volatility, thermal and chemical stability, and competition with porous solids will also be discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Methyl Ketones from Municipal Solid Waste Blends by One‐Pot Ionic‐Liquid Pretreatment, Saccharification, and Fermentation

Abstract The conversion of municipal solid waste (MSW) and lignocellulosic biomass blends to methyl ketones (MKs) was investigated by using bioderived ionic liquid (bionic liquid)‐based hydrolysates followed by fermentation with an engineered Escherichia coli strain. The hydrolysates were produced by a one‐pot process using six types of MSW–biomass blends, choline‐based bionic liquids, and commercial enzymes. Based on the sugar yields, one blend (corn stover/MSW=95:5, w / w ) and two bionic liquids {cholinium lysinate ([Ch][Lys]) and cholinium aspartate ([Ch] 2 [Asp])} were selected for scale‐up studies. Maximum yields of 82.3 % glucose and 54.4 % xylose were obtained from the selected blend in the scale‐up studies (6 L), which was comparable with 83.6 % glucose and 52.8 % xylose obtained at a smaller scale (0.2 L). Comparable or higher yields of medium‐chain (C 11 –C 17 ) MKs were achieved by using the MSW–biomass blend‐derived hydrolysates, relative to the sugar controls (glucose and xylose) with similar sugar feeding concentrations. Up to 1145 mg L −1 of MKs was produced by using MSW–biomass‐derived hydrolysates, and the MK titer decreased to 300 mg L −1 when the bionic‐liquid concentration in the hydrolysate increased from 1 to 2 %, indicative of bionic‐liquid inhibition. Technoeconomic analysis was conducted to investigate the economic potential of using the selected MSW–biomass blend as a feedstock to produce MKs.

Yan, Jipeng↗
DOE OSTI2021

Verification of numerical models for seismic fluid-structure interaction analysis of internal components in liquid-filled advanced reactors

Earthquake shaking of a liquid-filled advanced reactor induces fluid-structure interaction (FSI) between the reactor vessel (tank), its internal components, and the contained liquid. Seismic design, qualification, and risk assessment of such reactors must consider fluid-structure responses, their geometries and support conditions, and three-directional seismic inputs, all of which require numerical simulations. Numerical models used for analysis of safety-related nuclear equipment must be verified and validated. Here, this paper verifies numerical models of submerged components using analytical solutions. Seismic FSI analysis of the numerical models is performed using the Arbitrary Lagrangian-Eulerian (ALE) and Incompressible Computational Fluid Dynamics (ICFD) solvers in LS-DYNA. Prior analytical solutions are reworked in this paper, and calculation errors are identified and corrected. The solutions address frequencies of two concentric cylindrical pipes filled with liquid: the inner pipe is a submerged component, and the outer pipe contains the liquid. A unitless frequency coefficient is defined and presented for pipes of different materials, filled with different liquids, and with a range of dimensions for application to advanced reactors. The numerical models are verified here by comparing the lateral frequencies of submerged components with those calculated using the corrected analytical solutions. Recommendations for verification of numerical models of internal components in advanced reactors for seismic FSI analysis are provided. Although the unitless frequency coefficients and verification procedures are developed for application to advanced nuclear reactors, they are broadly applicable to FSI analysis of submerged components in liquid-filled vessels such as storage tanks, boilers, and steam generators.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2015

Probing the interaction of ionic liquids with graphene using surface-enhanced Raman spectroscopy

We report an in situ measurement of the interaction of an imidazolium-based room temperature ionic liquid with both pure silver and a graphene-over-silver electrode under an applied electrochemical potential. At a negative applied potential, overall signal intensity increased indicating enhanced ionic liquid concentration at both silver and graphene electrodes. Vibrational modes associated with the imidazolium ring exhibited greater intensity enhancements and larger peak shifts compared with the anion indicating that the cation adsorbs with the ring and alkyl chain parallel to the electrode surface for both silver and graphene. In contrast to the silver, the surface enhanced Raman spectra of the ionic liquid near graphene showed shifts in the cation peaks even at no applied potential because of the strong π–π interaction between the ionic liquid and the graphene. Furthermore, the intensity of the graphene peak decreased in the presence of ionic liquid possibly due to the interaction between the ionic liquid and graphene. In conclusion, these results illustrate the effectiveness of surface-enhanced Raman spectroscopy to investigate electrolyte interactions with graphene at the liquid/electrode interface.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗