Method for converting UF5 to UF4 in a molten fluoride salt

DOEpatents

Bennett, Melvin R.; Bamberger, Carlos E.; Kelmers, A. Donald

1977-01-01

The reduction of UF.sub.5 to UF.sub.4 in a molten fluoride salt by sparging with hydrogen is catalyzed by metallic platinum. The reaction is also catalyzed by platinum alloyed with gold reaction equipment.

Molten salts and energy related materials.

PubMed

Fray, Derek

2016-08-15

Molten salts have been known for centuries and have been used for the extraction of aluminium for over one hundred years and as high temperature fluxes in metal processing. This and other molten salt routes have gradually become more energy efficient and less polluting, but there have been few major breakthroughs. This paper will explore some recent innovations that could lead to substantial reductions in the energy consumed in metal production and in carbon dioxide production. Another way that molten salts can contribute to an energy efficient world is by creating better high temperature fuel cells and novel high temperature batteries, or by acting as the medium that can create novel materials that can find applications in high energy batteries and other energy saving devices, such as capacitors. Carbonate melts can be used to absorb carbon dioxide, which can be converted into C, CO and carbon nanoparticles. Molten salts can also be used to create black silicon that can absorb more sunlight over a wider range of wavelengths. Overall, there are many opportunities to explore for molten salts to play in an efficient, low carbon world.

Molten salt destruction of energetic waste materials

DOEpatents

Brummond, William A.; Upadhye, Ravindra S.; Pruneda, Cesar O.

1995-01-01

A molten salt destruction process is used to treat and destroy energetic waste materials such as high explosives, propellants, and rocket fuels. The energetic material is pre-blended with a solid or fluid diluent in safe proportions to form a fluid fuel mixture. The fuel mixture is rapidly introduced into a high temperature molten salt bath. A stream of molten salt is removed from the vessel and may be recycled as diluent. Additionally, the molten salt stream may be pumped from the reactor, circulated outside the reactor for further processing, and delivered back into the reactor or cooled and circulated to the feed delivery system to further dilute the fuel mixture entering the reactor.

Corrosion of SiC by Molten Salt

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Smialek, James L.

1987-01-01

Advanced ceramic materials considered for wide range of applications as in gas turbine engines and heat exchangers. In such applications, materials may be in corrosive environments that include molten salts. Very corrosive to alloys. In order to determine extent of problem for ceramic materials, corrosion of SiC by molten salts studied in both jet fuel burners and laboratory furnaces. Surface of silicon carbide corroded by exposure to flame seeded with 4 parts per million of sodium. Strength of silicon carbide decreased by corrosion in flame and tube-furnace tests.

Low temperature oxidation using support molten salt catalysts

DOEpatents

Weimer, Alan W.; Czerpak, Peter J.; Hilbert, Patrick M.

2003-05-20

Molten salt reactions are performed by supporting the molten salt on a particulate support and forming a fluidized bed of the supported salt particles. The method is particularly suitable for combusting hydrocarbon fuels at reduced temperatures, so that the formation NO.sub.x species is reduced. When certain preferred salts are used, such as alkali metal carbonates, sulfur and halide species can be captured by the molten salt, thereby reducing SO.sub.x and HCl emissions.

Use of Nitrogen Trifluoride To Purify Molten Salt Reactor Coolant and Heat Transfer Fluoride Salts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scheele, Randall D.; Casella, Andrew M.; McNamara, Bruce K.

2017-05-02

Abstract: The molten salt cooled nuclear reactor is included as one of the Generation IV reactor types. One of the challenges with the implementation of this reactor is purifying and maintaining the purity of the various molten fluoride salts that will be used as coolants. The method used for Oak Ridge National Laboratory’s molten salt experimental test reactor was to treat the coolant with a mixture of H2 and HF at 600°C. In this article we evaluate thermal NF3 treatment for purifying molten fluoride salt coolant candidates based on NF3’s 1) past use to purify fluoride salts, 2) other industrialmore » uses, 3) commercial availability, 4) operational, chemical, and health hazards, 5) environmental effects and environmental risk management methods, 6) corrosive properties, and 7) thermodynamic potential to eliminate impurities that could arise due to exposure to water and oxygen. Our evaluation indicates that nitrogen trifluoride is a viable and safer alternative to the previous method.« less

Novel approach to Zr powder production by smooth ZrCl4 bubbling through molten salt

NASA Astrophysics Data System (ADS)

Bae, Hyun-Na; Choi, Mi-Seon; Lee, Go-Gi; Kim, Seon-Hyo

2016-01-01

A reduction process using ZrCl4 bubbles as a reactant was investigated to produce zirconium metals. ZrCl4 vapor was bubbled through the lance in the bath, in which Mg melt and MgCl2 salt were separated. Zr powder was formed by a reduction of ZrCl4 bubbles in magnesium layer. However, the lance was clogged by the aggregate of zirconium occurred during ZrCl4 vapor injecting leading to interruption of ZrCl4 supply into the bath. This phenomenon could be caused by the presence of magnesium at the lance tip, which passes through MgCl2 salt during bubbling, and then zirconium was formed in the forms of intermetallic compounds with aluminum. In this study, the effect of molten salt on the troubled phenomena was investigated and it was verified that CaCl2 with relatively low Weber number meaning relatively high surface tension as molten salt is effective in inhibiting the lance clogging phenomena. Then, a few micrometer-sized Zr powder with the high purity of 91.6 wt% was obtained smoothly without the formation of intermetallic compound.

Alloys compatibility in molten salt fluorides: Kurchatov Institute related experience

NASA Astrophysics Data System (ADS)

Ignatiev, Victor; Surenkov, Alexandr

2013-10-01

In the last several years, there has been an increased interest in the use of high-temperature molten salt fluorides in nuclear power systems. For all molten salt reactor designs, materials selection is a very important issue. This paper summarizes results, which led to selection of materials for molten salt reactors in Russia. Operating experience with corrosion thermal convection loops has demonstrated good capability of the “nickel-molybdenum alloys + fluoride salt fueled by UF4 and PuF3 + cover gas” system up to 750 °C. A brief description is given of the container material work in progress. Tellurium corrosion of Ni-based alloys in stressed and unloaded conditions studies was also tested in different molten salt mixtures at temperatures up to 700-750 °C, also with measurement of the redox potential. HN80MTY alloy with 1% added Al is the most resistant to tellurium intergranular cracking of Ni-base alloys under study.

Thermal-hydraulics of internally heated molten salts and application to the Molten Salt Fast Reactor

NASA Astrophysics Data System (ADS)

Fiorina, Carlo; Cammi, Antonio; Luzzi, Lelio; Mikityuk, Konstantin; Ninokata, Hisashi; Ricotti, Marco E.

2014-04-01

The Molten Salt Reactors (MSR) are an innovative kind of nuclear reactors and are presently considered in the framework of the Generation IV International Forum (GIF-IV) for their promising performances in terms of low resource utilization, waste minimization and enhanced safety. A unique feature of MSRs is that molten fluoride salts play the distinctive role of both fuel (heat source) and coolant. The presence of an internal heat generation perturbs the temperature field and consequences are to be expected on the heat transfer characteristics of the molten salts. In this paper, the problem of heat transfer for internally heated fluids in a straight circular channel is first faced on a theoretical ground. The effect of internal heat generation is demonstrated to be described by a corrective factor applied to traditional correlations for the Nusselt number. It is shown that the corrective factor can be fully characterized by making explicit the dependency on Reynolds and Prandtl numbers. On this basis, a preliminary correlation is proposed for the case of molten fluoride salts by interpolating the results provided by an analytic approach previously developed at the Politecnico di Milano. The experimental facility and the related measuring procedure for testing the proposed correlation are then presented. Finally, the developed correlation is used to carry out a parametric investigation on the effect of internal heat generation on the main out-of-core components of the Molten Salt Fast Reactor (MSFR), the reference circulating-fuel MSR design in the GIF-IV. The volumetric power determines higher temperatures at the channel wall, but the effect is significant only in case of large diameters and/or low velocities.

Development of High-Temperature Transport Technologies of Molten Salt Slurry in Pyrometallurgical Reprocessing

NASA Astrophysics Data System (ADS)

Hijikata, Takatoshi; Koyama, Tadafumi

Pyrometallurgical-reprocessing is one of the most promising technologies for advanced fuel cycle with favorable economic potential and intrinsic proliferation resistance. The development of transport technology for molten salt is a key issue in the industrialization of pyro-reprocessing. As for pure molten LiCl-KCl eutectic salt at approximately 773 K, we have already reported the successful results of transport using gravity and a centrifugal pump. However, molten salt in an electrorefiner mixes with insoluble fines when spent fuel is dissolved in porous anode basket. The insoluble consists of noble metal fission products, such as Pd, Ru, Mo, and Zr. There have been very few transport studies of a molten salt slurry (metal fines-molten salt mixture). Hence, transport experiments on a molten salt slurry were carried out to investigate the behavior of the slurry in a tube. The apparatus used in the transport experiments on the molten salt slurry consisted of a supply tank, a 10° inclined transport tube (10 mm inner diameter), a valve, a filter, and a recovery tank. Stainless steel (SS) fines with diameters from 53 to 415 μm were used. To disperse these fines homogenously, the molten salt and fines were stirred in the supply tank by an impeller at speeds from 1200 to 2100 rpm. The molten salt slurry containing 0.04 to 0.4 vol.% SS fines was transported from the supply tank to the recovery tank through the transportation tube. In the recovery tank, the fines were separated from the molten salt by the filter to measure the transport behavior of molten salt and SS fines. When the velocity of the slurry was 0.02 m/s, only 1% of the fines were transported to the recovery tank. On the other hand, most of the fines were transported when the velocity of the slurry was more than 0.8 m/s. Consequently, the molten salt slurry can be transported when the velocity is more than 0.8 m/s.

Electrochemical ion separation in molten salts

DOEpatents

Spoerke, Erik David; Ihlefeld, Jon; Waldrip, Karen; Wheeler, Jill S.; Brown-Shaklee, Harlan James; Small, Leo J.; Wheeler, David R.

2017-12-19

A purification method that uses ion-selective ceramics to electrochemically filter waste products from a molten salt. The electrochemical method uses ion-conducting ceramics that are selective for the molten salt cations desired in the final purified melt, and selective against any contaminant ions. The method can be integrated into a slightly modified version of the electrochemical framework currently used in pyroprocessing of nuclear wastes.

Molten salt bath circulation design for an electrolytic cell

DOEpatents

Dawless, Robert K.; LaCamera, Alfred F.; Troup, R. Lee; Ray, Siba P.; Hosler, Robert B.

1999-01-01

An electrolytic cell for reduction of a metal oxide to a metal and oxygen has an inert anode and an upwardly angled roof covering the inert mode. The angled roof diverts oxygen bubbles into an upcomer channel, thereby agitating a molten salt bath in the upcomer channel and improving dissolution of a metal oxide in the molten salt bath. The molten salt bath has a lower velocity adjacent the inert anode in order to minimize corrosion by substances in the bath. A particularly preferred cell produces aluminum by electrolysis of alumina in a molten salt bath containing aluminum fluoride and sodium fluoride.

Boric ester-type molten salt via dehydrocoupling reaction.

PubMed

Matsumi, Noriyoshi; Toyota, Yoshiyuki; Joshi, Prerna; Puneet, Puhup; Vedarajan, Raman; Takekawa, Toshihiro

2014-11-14

Novel boric ester-type molten salt was prepared using 1-(2-hydroxyethyl)-3-methylimidazolium chloride as a key starting material. After an ion exchange reaction of 1-(2-hydroxyethyl)-3-methylimidazolium chloride with lithium (bis-(trifluoromethanesulfonyl) imide) (LiNTf2), the resulting 1-(2-hydroxyethyl)-3-methylimidazolium NTf2 was reacted with 9-borabicyclo[3.3.1]nonane (9-BBN) to give the desired boric ester-type molten salt in a moderate yield. The structure of the boric ester-type molten salt was supported by 1H-, 13C-, 11B- and 19F-NMR spectra. In the presence of two different kinds of lithium salts, the matrices showed an ionic conductivity in the range of 1.1 × 10⁻⁴-1.6 × 10⁻⁵ S cm⁻¹ at 51 °C. This was higher than other organoboron molten salts ever reported.

Cathode for molten salt batteries

DOEpatents

Mamantov, Gleb; Marassi, Roberto

1977-01-01

A molten salt electrochemical system for battery applications comprises tetravalent sulfur as the active cathode material with a molten chloroaluminate solvent comprising a mixture of AlCl.sub.3 and MCl having a molar ratio of AlCl.sub.3 /MCl from greater than 50.0/50.0 to 80/20.

Metals Electroprocessing in Molten Salts

NASA Technical Reports Server (NTRS)

Sadoway, D. R.

1985-01-01

The present study seeks to explain the poor quality of solid electrodeposits in molten salts through a consideration of the effects of fluid flow of the electrolyte. Transparent cells allow observation of electrolyte circulation by a laser schlieren optical technique during the electrodeposition of solid zinc from the molten salt electrolyte, ZnCl2 - LiCl-KCl. Experimental variables are current, density, electrolyte composition, and cell geometry. Based on the results of earlier electrodeposition studies as well as reports in the literature, these parameters are identified as having the primary influence on cell performance and deposit quality. Experiments are conducted to measure the fluid flow patterns and the electrochemical cell characteristics, and to correlate this information with the morphology of the solid electrodeposit produced. Specifically, cell voltage, cell current, characteristic time for dendrite evolution, and dendrite growth directions are noted. Their relationship to electrolyte flow patterns and the morphology of the resulting electrodeposit are derived. Results to date indicate that laser schlieren imaging is capable of revealing fluid flow patterns in a molten salt electrolyte.

Moderate temperature sodium cells. V - Discharge reactions and rechargeability of NiS and NiS2 positive electrodes in molten NaAlCl4

NASA Technical Reports Server (NTRS)

Abraham, K. M.; Elliot, J. E.

1984-01-01

NiS2 and NiS have been characterized as high energy density rechargeable positive electrodes for moderate-temperature Na batteries of the configuration, Na(1)/beta double prime-Al2O3/NaAlCl4(1), NiSx. The batteries operate in the temperature range 170 - 190 C. Positive electrode reactions during discharge/charge cycles have been characterized. Excellent rechargeability of the batteries has been demonstrated by extended cell cycling. A Na/NiS2 cell, operating at 190 C, exceeded 600 deep discharge/charge cycles with practically no capacity deterioration. The feasibility of secondary Na/NiSx batteries with specific energies equal to or greater than 50 Wh/lb and cycle lifes exceeding 1000 deep discharge/charge cycles has been demonstrated.

Delivery system for molten salt oxidation of solid waste

DOEpatents

Brummond, William A.; Squire, Dwight V.; Robinson, Jeffrey A.; House, Palmer A.

2002-01-01

The present invention is a delivery system for safety injecting solid waste particles, including mixed wastes, into a molten salt bath for destruction by the process of molten salt oxidation. The delivery system includes a feeder system and an injector that allow the solid waste stream to be accurately metered, evenly dispersed in the oxidant gas, and maintained at a temperature below incineration temperature while entering the molten salt reactor.

Molten Salts for High Temperature Reactors: University of Wisconsin Molten Salt Corrosion and Flow Loop Experiments -- Issues Identified and Path Forward

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piyush Sabharwall; Matt Ebner; Manohar Sohal

2010-03-01

Considerable amount of work is going on regarding the development of high temperature liquid salts technology to meet future process needs of Next Generation Nuclear Plant. This report identifies the important characteristics and concerns of high temperature molten salts (with lesson learned at University of Wisconsin-Madison, Molten Salt Program) and provides some possible recommendation for future work

Advanced heat exchanger development for molten salts

DOE PAGES

Sabharwall, Piyush; Clark, Denis; Glazoff, Michael; ...

2014-12-01

This study addresses present work concerned with advanced heat exchanger development for molten salt in nuclear and non nuclear thermal systems. The molten salt systems discussed herein use alloys, such as Hastelloy N and 242, which show corrosion resistance to molten salt at nominal operating temperatures up to 700°C. These alloys were diffusion welded, and the corresponding information is presented. Test specimens were prepared for exposing diffusion welds to molten salt environments. Hastelloy N and 242 were found to be weldable by diffusion welding, with ultimate tensile strengths about 90% of base metal values. Both diffusion welds and sheet materialmore » in Hastelloy N were corrosion tested in?58 mol% KF and 42 mol% ZrF4 at 650, 700, and 850°C for 200, 500, and 1,000 hours. Corrosion rates found were similar between welded and nonwelded materials, typically <10 mils per year. For materials of construction, nickel and alloys with dense nickel coatings are effectively inert to corrosion in fluorides, but not so in chlorides. Hence, additional testing of selected alloys for resistance to intergranular corrosion is needed, as is a determination of corrosion rate as a function of contaminant type and alloy composition with respect to chromium and carbon to better define the optimal chromium and carbon composition, independent of galvanic or differential solubility effects. Also presented is the division of the nuclear reactor and high temperature components per ASME standards, along with design requirements for a subcritical Rankine power cycle heat exchanger that has to overcome pressure difference of about 17 MPa.« less

Nuclear Hybrid Energy System: Molten Salt Energy Storage (Summer Report 2013)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabharwall, Piyush; mckellar, Michael George; Yoon, Su-Jong

2013-11-01

Effective energy use is a main focus and concern in the world today because of the growing demand for energy. The nuclear hybrid energy system (NHES) is a valuable technical concept that can potentially diversify and leverage existing energy technologies. This report considers a particular NHES design that combines multiple energy systems including a nuclear reactor, energy storage system (ESS), variable renewable generator (VRG), and additional process heat applications. Energy storage is an essential component of this particular NHES because its design allows the system to produce peak power while the nuclear reactor operates at constant power output. Many energymore » storage options are available, but this study mainly focuses on a molten salt ESS. The primary purpose of the molten salt ESS is to enable the nuclear reactor to be a purely constant heat source by acting as a heat storage component for the reactor during times of low demand, and providing additional capacity for thermo-electric power generation during times of peak electricity demand. This report will describe the rationale behind using a molten salt ESS and identify an efficient molten salt ESS configuration that may be used in load following power applications. Several criteria are considered for effective energy storage and are used to identify the most effective ESS within the NHES. Different types of energy storage are briefly described with their advantages and disadvantages. The general analysis to determine the most efficient molten salt ESS involves two parts: thermodynamic, in which energetic and exergetic efficiencies are considered; and economic. Within the molten salt ESS, the two-part analysis covers three major system elements: molten salt ESS designs (two tank direct and thermocline), the molten salt choice, and the different power cycles coupled with the molten salt ESS. Analysis models are formulated and analyzed to determine the most effective ESS. The results show that the

Cathodes for molten-salt batteries

NASA Technical Reports Server (NTRS)

Argade, Shyam D.

1993-01-01

Viewgraphs of the discussion on cathodes for molten-salt batteries are presented. For the cathode reactions in molten-salt cells, chlorine-based and sulfur-based cathodes reactants have relatively high exchange current densities. Sulfur-based cathodes, metal sulfides, and disulfides have been extensively investigated. Primary thermal batteries of the Li-alloy/FeS2 variety have been available for a number of years. Chlorine based rechargable cathodes were investigated for the pulse power application. A brief introduction is followed by the experimental aspects of research, and the results obtained. Performance projections to the battery system level are discussed and the presentation is summarized with conclusions.

Corrosion-induced microstructural developments in 316 stainless steel during exposure to molten Li 2BeF 4(FLiBe) salt

DOE PAGES

Zheng, Guiqiu; He, Lingfeng; Carpenter, David; ...

2016-10-12

The microstructural evaluation and characterization of 316 stainless steel samples that were tested in molten Li 2BeF 4 (FLiBe) salt were investigated in this study for evaluating its performance in high-temperature molten fluoride salts. Recently, 316 stainless steel and FLiBe salt are being actively considered as the main structural alloy and primary coolant of fluoride salt-cooled high-temperature reactor (FHR), a leading nuclear reactor concept for the next generation nuclear plants (NGNP). In support of the materials development for the FHR, high-temperature corrosion tests of 316 stainless steel in molten FLiBe salt at 700°C have been conducted in both bare graphitemore » crucibles and 316 stainless steel-lined crucibles in an inert atmosphere for up to 3000 hours. The microstructure of the tested samples was comprehensively characterized using scanning electron microscopy (SEM) in conjunction with energy dispersive x-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD), and scanning transmission electron microscopy (STEM) with EDS. In addition to the noticeable intergranular corrosion attack on surface, the corrosion in terms of the Cr depletion along high angle grain boundaries (15-180º) extended to 22µm in depth after 3000-hour exposure to molten FLiBe salt in graphite crucible. The coherent Σ3 grain boundary appeared high resistance to the Cr depletion. The substantial Cr depletion from the near-to-surface layer induced phase transformation from γ-martensite to α-ferrite phase (FeNi x) during corrosion at 700ºC. Furthermore, the presence of graphite in the molten salt doubled the corrosion attack depth and led to the formation of round Mo2C, hexagonal Cr 7C 3 and needle-like Al 4C 3 phase within the alloy as deep as 50 µm after 3000-hour corrosion testing. Based on the microstructural analysis, the corrosion mechanisms of 316 stainless steel in molten FLiBe salt in different corrosion crucibles were illuminated through schematic

Corrosion-induced microstructural developments in 316 stainless steel during exposure to molten Li 2BeF 4(FLiBe) salt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Guiqiu; He, Lingfeng; Carpenter, David

The microstructural evaluation and characterization of 316 stainless steel samples that were tested in molten Li 2BeF 4 (FLiBe) salt were investigated in this study for evaluating its performance in high-temperature molten fluoride salts. Recently, 316 stainless steel and FLiBe salt are being actively considered as the main structural alloy and primary coolant of fluoride salt-cooled high-temperature reactor (FHR), a leading nuclear reactor concept for the next generation nuclear plants (NGNP). In support of the materials development for the FHR, high-temperature corrosion tests of 316 stainless steel in molten FLiBe salt at 700°C have been conducted in both bare graphitemore » crucibles and 316 stainless steel-lined crucibles in an inert atmosphere for up to 3000 hours. The microstructure of the tested samples was comprehensively characterized using scanning electron microscopy (SEM) in conjunction with energy dispersive x-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD), and scanning transmission electron microscopy (STEM) with EDS. In addition to the noticeable intergranular corrosion attack on surface, the corrosion in terms of the Cr depletion along high angle grain boundaries (15-180º) extended to 22µm in depth after 3000-hour exposure to molten FLiBe salt in graphite crucible. The coherent Σ3 grain boundary appeared high resistance to the Cr depletion. The substantial Cr depletion from the near-to-surface layer induced phase transformation from γ-martensite to α-ferrite phase (FeNi x) during corrosion at 700ºC. Furthermore, the presence of graphite in the molten salt doubled the corrosion attack depth and led to the formation of round Mo2C, hexagonal Cr 7C 3 and needle-like Al 4C 3 phase within the alloy as deep as 50 µm after 3000-hour corrosion testing. Based on the microstructural analysis, the corrosion mechanisms of 316 stainless steel in molten FLiBe salt in different corrosion crucibles were illuminated through schematic

Apparatus and method for stripping tritium from molten salt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holcomb, David E.; Wilson, Dane F.

A method of stripping tritium from flowing stream of molten salt includes providing a tritium-separating membrane structure having a porous support, a nanoporous structural metal-ion diffusion barrier layer, and a gas-tight, nonporous palladium-bearing separative layer, directing the flowing stream of molten salt into contact with the palladium-bearing layer so that tritium contained within the molten salt is transported through the tritium-separating membrane structure, and contacting a sweep gas with the porous support for collecting the tritium.

High-temperature corrosion of UNS N10003 in molten Li 2BeF 4 (FLiBe) salt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Guiqiu; Kelleher, Brian; He, Lingfeng

2015-07-30

Here, corrosion testing of Hastelloy N in molten fluoride salt was performed in purified molten 2 7LiF-BeF 2 (66-34mol%) (FLiBe) salt at 700°C for 1000 hours, in pure nickel and graphite capsules. In the nickel capsule tests, the near-surface region of the alloy exhibited an about 200 nm porous structure, an approximately 3.5 μm chromium depleted region, and MoSi 2 precipitates. In tests performed in graphite capsules, the alloy samples gained weight due to the formation of a variety of Cr 3C 2, Cr 7C 3, Mo 2C and Cr 23C 6, carbide phases on the surface and in themore » subsurface regions of the alloy. A Cr depleted region was observed in the near-surface region where Mo thermally diffused toward either surface or grain boundary, which induced approximately 1.4 μm Ni 3Fe alloy layer in this region. The carbide containing layer extended to about 7 μm underneath the Ni 3Fe layer. The presence of graphite dramatically changes the mechanisms of corrosion attack in Hastelloy N in molten FLiBe salt. Evaluated by in terms of the depth of attack, graphite clearly accelerates corrosion, but the results appear to indicate that the formation of Cr 23C 6 phase might stabilize the Cr and mitigate its dissolution in molten FLiBe salt.« less

A Possible Regenerative, Molten-Salt, Thermoelectric Fuel Cell

NASA Technical Reports Server (NTRS)

Greenberg, Jacob; Thaller, Lawrence H.; Weber, Donald E.

1964-01-01

Molten or fused salts have been evaluated as possible thermoelectric materials because of the relatively good values of their figures of merit, their chemical stability, their long liquid range, and their ability to operate in conjunction with a nuclear reactor to produce heat. In general, molten salts are electrolytic conductors; therefore, there will be a transport of materials and subsequent decomposition with the passage of an electric current. It is possible nonetheless to overcome this disadvantage by using the decomposition products of the molten-salt electrolyte in a fuel cell. The combination of a thermoelectric converter and a fuel cell would lead to a regenerative system that may be useful.

Maintaining molten salt electrolyte concentration in aluminum-producing electrolytic cell

DOEpatents

Barnett, Robert J.; Mezner, Michael B.; Bradford, Donald R

2005-01-04

A method of maintaining molten salt concentration in a low temperature electrolytic cell used for production of aluminum from alumina dissolved in a molten salt electrolyte contained in a cell free of frozen crust wherein volatile material is vented from the cell and contacted and captured on alumina being added to the cell. The captured volatile material is returned with alumina to cell to maintain the concentration of the molten salt.

High temperature molten salt storage

NASA Astrophysics Data System (ADS)

Ives, J.; Newcomb, J. C.; Pard, A. G.

1985-10-01

The design of a high-temperature molten salt thermal energy storage (TES) concept, including some materials testing, was developed by Rockwell International's Rocketdyne Division (RD), under contract to SERI, and is described in this document. The main features of the concept are a conical hot tank with a liner and internal insulation that allows unrestricted relative thermal expansion and the use of cathodic protection (impressed voltage) to inhibit corrosion. The RD design uses two tanks and ternary eutectic lithium-sodium-potassium carbonates for sensible heat storage. The tanks were sized for 6 h of storage at a discharge rate of 300 MW, giving 1800 MWh total usable thermal storage capacity. The molten carbonate storage medium is cycled between 425 and 900C. From the design study, no definitive statement can be made as to the cost-effectiveness of cathodic protection. Several anode design issues need to be resolved before cathodic protection can significantly reduce corrosion where the liner comes in contact with molten salts. However, where the tank is exposed to salt vapor, the large corrosion allowance required for the liner without cathodic protection results in a much thicker liner wall and shorter liner life than originally perceived, which affects system costs significantly.

Facile morphology-controlled synthesis and luminescence properties of BaMoO4:Eu3+ microparticles and micro-rods obtained by a molten-salt reaction route.

PubMed

Xia, Zhiguo; Jin, Shuai; Sun, Jiayue; Du, Haiyan; Du, Peng; Liao, Libing

2011-11-01

This work focuses on the synthesis of morphology-controlled BaMoO4:Eu3+ micro-crystals such as microparticles and micro-rods using a facile molten salt method, and their morphology, structural characterization, and luminescent properties were comparatively investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fluorescence spectra. The molten salt method synthesized products from a reaction of BaMoO4 precursor obtained by a co-precipitation method of BaCl2 and Na2MoO4 with an eutectic salt mixture of NaCl-KCl at 700 degrees C. Detailed studies revealed that the formation of the different morphologies of the micro-crystals was strongly dependent on the weight ratio of the salt (NaCl-KCl) to the BaMoO4 precursor, and the formation mechanism of the products in the present molten salt system was also investigated. Based on the investigations of the photoluminescence properties, the samples with different morphologies prepared by the molten salt method had the strongest red emission at 615 nm, corresponding to the Eu3+ 5D0-7F2 transition in the BaMoO4 host lattice, and the emission intensity of BaMoO4:Eu3+ microparticles was stronger than that of BaMoO4:Eu3+ micro-rods.

Novel waste printed circuit board recycling process with molten salt.

PubMed

Riedewald, Frank; Sousa-Gallagher, Maria

2015-01-01

The objective of the method was to prove the concept of a novel waste PCBs recycling process which uses inert, stable molten salts as the direct heat transfer fluid and, simultaneously, uses this molten salt to separate the metal products in either liquid (solder, zinc, tin, lead, etc.) or solid (copper, gold, steel, palladium, etc.) form at the operating temperatures of 450-470 °C. The PCB recovery reactor is essentially a U-shaped reactor with the molten salt providing a continuous fluid, allowing molten salt access from different depths for metal recovery. A laboratory scale batch reactor was constructed using 316L as suitable construction material. For safety reasons, the inert, stable LiCl-KCl molten salts were used as direct heat transfer fluid. Recovered materials were washed with hot water to remove residual salt before metal recovery assessment. The impact of this work was to show metal separation using molten salts in one single unit, by using this novel reactor methodology. •The reactor is a U-shaped reactor filled with a continuous liquid with a sloped bottom representing a novel reactor concept.•This method uses large PCB pieces instead of shredded PCBs as the reactor volume is 2.2 L.•The treated PCBs can be removed via leg B while the process is on-going.

Novel waste printed circuit board recycling process with molten salt

PubMed Central

Riedewald, Frank; Sousa-Gallagher, Maria

2015-01-01

The objective of the method was to prove the concept of a novel waste PCBs recycling process which uses inert, stable molten salts as the direct heat transfer fluid and, simultaneously, uses this molten salt to separate the metal products in either liquid (solder, zinc, tin, lead, etc.) or solid (copper, gold, steel, palladium, etc.) form at the operating temperatures of 450–470 °C. The PCB recovery reactor is essentially a U-shaped reactor with the molten salt providing a continuous fluid, allowing molten salt access from different depths for metal recovery. A laboratory scale batch reactor was constructed using 316L as suitable construction material. For safety reasons, the inert, stable LiCl–KCl molten salts were used as direct heat transfer fluid. Recovered materials were washed with hot water to remove residual salt before metal recovery assessment. The impact of this work was to show metal separation using molten salts in one single unit, by using this novel reactor methodology. • The reactor is a U-shaped reactor filled with a continuous liquid with a sloped bottom representing a novel reactor concept. • This method uses large PCB pieces instead of shredded PCBs as the reactor volume is 2.2 L. • The treated PCBs can be removed via leg B while the process is on-going. PMID:26150977

Summary of the Workshop on Molten Salt Reactor Technologies Commemorating the 50th Anniversary of the Startup of the Molten Salt Reactor Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Betzler, Benjamin R; Mays, Gary T

2016-01-01

A workshop on Molten Salt Reactor (MSR) technologies commemorating the 50th anniversary of the Molten Salt Reactor Experiment (MSRE) was held at Oak Ridge National Laboratory on October 15 16, 2015. The MSRE represented a pioneering experiment that demonstrated an advanced reactor technology: the molten salt eutectic-fueled reactor. A multinational group of more than 130 individuals representing a diverse set of stakeholders gathered to discuss the historical, current, and future technical challenges and paths to deployment of MSR technology. This paper provides a summary of the key messages from this workshop.

Absorption and desorption of SO2 in aqueous solutions of diamine-based molten salts.

PubMed

Lim, Seung Rok; Hwang, Junhyeok; Kim, Chang Soo; Park, Ho Seok; Cheong, Minserk; Kim, Hoon Sik; Lee, Hyunjoo

2015-05-30

SO2 absorption and desorption behaviors were investigated in aqueous solutions of diamine-derived molten salts with a tertiary amine group on the cation and a chloride anion, including butyl-(2-dimethylaminoethyl)-dimethylammonium chloride ([BTMEDA]Cl, pKb=8.2), 1-butyl-1,4-dimethylpiperazinium chloride ([BDMP]Cl, pKb=9.8), and 1-butyl-4-aza-1-azoniabicyclo[2,2,2]octane chloride ([BDABCO]Cl, pKb=11.1). The SO2 absorption and desorption performance of the molten salt were greatly affected by the basicity of the molten salt. Spectroscopic, X-ray crystallographic, and computational results for the interactions of SO2 with molten salts suggest that two types of SO2-containg species could be generated depending on the basicity of the unquaternized amino group: a dicationic species comprising two different anions, HSO3(-) and Cl(-), and a monocationic species bearing Cl(-) interacting with neutral H2SO3. Copyright © 2015 Elsevier B.V. All rights reserved.

Molten salt-mediated formation of g-C3N4-MoS2 for visible-light-driven photocatalytic hydrogen evolution

NASA Astrophysics Data System (ADS)

Li, Ni; Zhou, Jing; Sheng, Ziqiong; Xiao, Wei

2018-02-01

Construction of two-dimensional/two-dimensional (2D/2D) hybrid with well-defined composition and microstructure is a general protocol to achieve high-performance catalysts. We herein report preparation of g-C3N4-MoS2 hybrid by pyrolysis of affordable melamine and (NH4)2MoS4 in molten LiCl-NaCl-KCl at 550 °C. Molten salts are confirmed as ideal reaction media for formation of homogeneous hybrid. Characterizations suggest a strong interaction between g-C3N4 and MoS2 in the hybrid, which results in an enhanced visible-light-driven photocatalytic hydrogen generation of the hybrid with an optimal g-C3N4/MoS2 ratio. The present study highlights the merits of molten salt methods on preparation of 2D photocatalysts and provides a rational design of 2D/2D hybrid catalysts for advanced environmental and energy applications.

Techniques for Measuring Solubility and Electrical Conductivity in Molten Salts

NASA Astrophysics Data System (ADS)

Su, Shizhao; Villalon, Thomas; Pal, Uday; Powell, Adam

Eutectic MgF2-CaF2 based salt containing YF3, CaO and Al2O3 additions were used in this study. The electrical conductivity was measured as a function of temperature by a calibration-free coaxial electrode setup. The materials selection and setup design were optimized to accurately measure the electrical conductivity of the highly conductive molten salts (>1 S/cm). The solubility and diffusion behavior of alumina and zirconia in the molten salts were investigated by drawing and holding the molten salt for different lengths of time within capillary tubes made of alumina and zirconia, respectively. After the time-dependent high temperature holds, the samples were cooled and the solubility of the solute within the molten salt was determined using scanning electron microscopy, energy-dispersive X-ray spectroscopy analysis and wavelength-dispersive X-ray spectroscopy analysis.

Advanced Instrumentation for Molten Salt Flow Measurements at NEXT

NASA Astrophysics Data System (ADS)

Tuyishimire, Olive

2017-09-01

The Nuclear Energy eXperiment Testing (NEXT) Lab at Abilene Christian University is building a Molten Salt Loop to help advance the technology of molten salt reactors (MSR). NEXT Lab's aim is to be part of the solution for the world's top challenges by providing safe, clean, and inexpensive energy, clean water and medical Isotopes. Measuring the flow rate of the molten salt in the loop is essential to the operation of a MSR. Unfortunately, there is no flow meter that can operate in the high temperature and corrosive environment of a molten salt. The ultrasonic transit time method is proposed as one way to measure the flow rate of high temperature fluids. Ultrasonic flow meter uses transducers that send and receive acoustic waves and convert them into electrical signals. Initial work presented here focuses on the setup of ultrasonic transducers. This presentation is the characterization of the pipe-fluid system with water as a baseline for future work.

Experimental investigation of a molten salt thermocline storage tank

NASA Astrophysics Data System (ADS)

Yang, Xiaoping; Yang, Xiaoxi; Qin, Frank G. F.; Jiang, Runhua

2016-07-01

Thermal energy storage is considered as an important subsystem for solar thermal power stations. Investigations into thermocline storage tanks have mainly focused on numerical simulations because conducting high-temperature experiments is difficult. In this paper, an experimental study of the heat transfer characteristics of a molten salt thermocline storage tank was conducted by using high-temperature molten salt as the heat transfer fluid and ceramic particle as the filler material. This experimental study can verify the effectiveness of numerical simulation results and provide reference for engineering design. Temperature distribution and thermal storage capacity during the charging process were obtained. A temperature gradient was observed during the charging process. The temperature change tendency showed that thermocline thickness increased continuously with charging time. The slope of the thermal storage capacity decreased gradually with the increase in time. The low-cost filler material can replace the expensive molten salt to achieve thermal storage purposes and help to maintain the ideal gravity flow or piston flow of molten salt fluid.

[Bio-oil production from biomass pyrolysis in molten salt].

PubMed

Ji, Dengxiang; Cai, Tengyue; Ai, Ning; Yu, Fengwen; Jiang, Hongtao; Ji, Jianbing

2011-03-01

In order to investigate the effects of pyrolysis conditions on bio-oil production from biomass in molten salt, experiments of biomass pyrolysis were carried out in a self-designed reactor in which the molten salt ZnCl2-KCl (with mole ratio 7/6) was selected as heat carrier, catalyst and dispersion agent. The effects of metal salt added into ZnCl2-KCl and biomass material on biomass pyrolysis were discussed, and the main compositions of bio-oil were determined by GC-MS. Metal salt added into molten salt could affect pyrolysis production yields remarkably. Lanthanon salt could enhance bio-oil yield and decrease water content in bio-oil, when mole fraction of 5.0% LaCl3 was added, bio-oil yield could reach up to 32.0%, and water content of bio-oil could reduce to 61.5%. The bio-oil and char yields were higher when rice straw was pyrolysed, while gas yield was higher when rice husk was used. Metal salts showed great selectivity on compositions of bio-oil. LiCl and FeCl2 promoted biomass to pyrolyse into smaller molecular weight compounds. CrCl3, CaCl2 and LaCl3 could restrain second pyrolysis of bio-oil. The research provided a scientific reference for production of bio-oil from biomass pyrolysis in molten salt.

Primary and secondary room temperature molten salt electrochemical cells

NASA Astrophysics Data System (ADS)

Reynolds, G. F.; Dymek, C. J., Jr.

1985-07-01

Three novel primary cells which use room temperature molten salt electrolytes are examined and found to have high open circuit potentials in the 1.75-2.19 V range, by comparison with the Al/AlCl3-MEICl concentration cell; their cathodes were of FeCl3-MEICl, WCl6-MEICl, and Br2/reticulated vitreous carbon together with Pt. Also, secondary electrochemical cell candidates were examined which combined the reversible Al/AlCl3-MEICl electrode with reversible zinc and cadmium molten salt electrodes to yield open circuit potentials of about 0.7 and 1.0 V, respectively. Room temperature molten salts' half-cell reduction potentials are given.

Laser-Induced Breakdown Spectroscopy (LIBS) in a Novel Molten Salt Aerosol System.

PubMed

Williams, Ammon N; Phongikaroon, Supathorn

2017-04-01

In the pyrochemical separation of used nuclear fuel (UNF), fission product, rare earth, and actinide chlorides accumulate in the molten salt electrolyte over time. Measuring this salt composition in near real-time is advantageous for operational efficiency, material accountability, and nuclear safeguards. Laser-induced breakdown spectroscopy (LIBS) has been proposed and demonstrated as a potential analytical approach for molten LiCl-KCl salts. However, all the studies conducted to date have used a static surface approach which can lead to issues with splashing, low repeatability, and poor sample homogeneity. In this initial study, a novel molten salt aerosol approach has been developed and explored to measure the composition of the salt via LIBS. The functionality of the system has been demonstrated as well as a basic optimization of the laser energy and nebulizer gas pressure used. Initial results have shown that this molten salt aerosol-LIBS system has a great potential as an analytical technique for measuring the molten salt electrolyte used in this UNF reprocessing technology.

Measurement of europium (III)/europium (II) couple in fluoride molten salt for redox control in a molten salt reactor concept

NASA Astrophysics Data System (ADS)

Guo, Shaoqiang; Shay, Nikolas; Wang, Yafei; Zhou, Wentao; Zhang, Jinsuo

2017-12-01

The fluoride molten salt such as FLiNaK and FLiBe is one of the coolant candidates for the next generation nuclear reactor concepts, for example, the fluoride salt cooled high temperature reactor (FHR). For mitigating corrosion of structural materials in molten fluoride salt, the redox condition of the salts needs to be monitored and controlled. This study investigates the feasibility of applying the Eu3+/Eu2+ couple for redox control. Cyclic voltammetry measurements of the Eu3+/Eu2+ couple were able to obtain the concentrations ratio of Eu3+/Eu2+ in the melt. Additionally, the formal standard potential of Eu3+/Eu2+ was characterized over the FHR's operating temperatures allowing for the application of the Nernst equation to establish a Eu3+/Eu2+ concentration ratio below 0.05 to prevent corrosion of candidate structural materials. A platinum quasi-reference electrode with potential calibrated by potassium reduction potential is shown as reliable for the redox potential measurement. These results show that the Eu3+/Eu2+ couple is a feasible redox buffering agent to control the redox condition in molten fluoride salts.

Effects of Cations on Corrosion of Inconel 625 in Molten Chloride Salts

NASA Astrophysics Data System (ADS)

Zhu, Ming; Ma, Hongfang; Wang, Mingjing; Wang, Zhihua; Sharif, Adel

2016-04-01

Hot corrosion of Inconel 625 in sodium chloride, potassium chloride, magnesium chloride, calcium chloride and their mixtures with different compositions is conducted at 900°C to investigate the effects of cations in chloride salts on corrosion behavior of the alloy. XRD, SEM/EDS were used to analyze the compositions, phases, and morphologies of the corrosion products. The results showed that Inconel 625 suffers more severe corrosion in alkaline earth metal chloride molten salts than alkaline metal chloride molten salts. For corrosion in mixture salts, the corrosion rate increased with increasing alkaline earth metal chloride salt content in the mixture. Cations in the chloride molten salts mainly affect the thermal and chemical properties of the salts such as vapor pressure and hydroscopicities, which can affect the basicity of the molten salt. Corrosion of Inconel 625 in alkaline earth metal chloride salts is accelerated with increasing basicity.

Studies of metals electroprocessing in molten salts

NASA Technical Reports Server (NTRS)

Sadoway, D. R.

1982-01-01

Fluid flow patterns in molten salt electrolytes were observed in order to determine how mass transport affects the morphology of the metal deposit. Studies conducted on the same metal, both in aqueous electrolytes in which coherent solid electrodeposits are produced, as well as in transparent molten salt electrolytes are described. Process variables such as current density and composition of the electrolyte are adjusted to change the morphology of the electrodeposit and, thus, to permit the study of the nature of electrolyte flow in relation to the quality of the electrodeposit.

Stabilization of 238Pu-contaminated combustible waste by molten salt oxidation

NASA Astrophysics Data System (ADS)

Stimmel, Jay J.; Remerowski, Mary Lynn; Ramsey, Kevin B.; Heslop, J. Mark

2000-07-01

Surrogate studies were conducted using the molten salt oxidation system at the Naval Surface Warfare Center-Indian Head Division. This system uses a rotary feed system and an alumina molten salt oxidation vessel. The combustible materials were tested individually and together in a homogenized mixture. A slurry containing pyrolyzed cheesecloth ash spiked with cerium oxide, which is used as a surrogate for plutonium, and ethylene glycol were also treated in the molten salt oxidation vessel.

Facile molten salt synthesis of Li2NiTiO4 cathode material for Li-ion batteries.

PubMed

Wang, Yanming; Wang, Yajing; Wang, Fei

2014-01-01

Well-crystallized Li2NiTiO4 nanoparticles are rapidly synthesized by a molten salt method using a mixture of NaCl and KCl salts. X-ray diffraction pattern and scanning electron microscopic image show that Li2NiTiO4 has a cubic rock salt structure with an average particle size of ca. 50 nm. Conductive carbon-coated Li2NiTiO4 is obtained by a facile ball milling method. As a novel 4 V positive cathode material for Li-ion batteries, the Li2NiTiO4/C delivers high discharge capacities of 115 mAh g(-1) at room temperature and 138 mAh g(-1) and 50°C, along with a superior cyclability.

Facile molten salt synthesis of Li2NiTiO4 cathode material for Li-ion batteries

PubMed Central

2014-01-01

Well-crystallized Li2NiTiO4 nanoparticles are rapidly synthesized by a molten salt method using a mixture of NaCl and KCl salts. X-ray diffraction pattern and scanning electron microscopic image show that Li2NiTiO4 has a cubic rock salt structure with an average particle size of ca. 50 nm. Conductive carbon-coated Li2NiTiO4 is obtained by a facile ball milling method. As a novel 4 V positive cathode material for Li-ion batteries, the Li2NiTiO4/C delivers high discharge capacities of 115 mAh g-1 at room temperature and 138 mAh g-1 and 50°C, along with a superior cyclability. PMID:24855459

New molten salt systems for high temperature molten salt batteries: Ternary and quaternary molten salt systems based on LiF-LiCl, LiF-LiBr, and LiCl-LiBr

NASA Astrophysics Data System (ADS)

Fujiwara, Syozo; Inaba, Minoru; Tasaka, Akimasa

Using a new simulative technique developed by us, we systematically investigated new ternary or quaternary molten salt systems, which are based on LiF-LiCl, LiF-LiBr, and LiCl-LiBr binary systems, for use as electrolytes in thermal batteries, and evaluated their ionic conductivities and melting points experimentally. It was confirmed experimentally that LiF-LiBr-KF (melting point: 425 °C, ionic conductivity at 500 °C: 2.52 S cm -1), LiCl-LiBr-KF (405 °C, 2.56 S cm -1), LiCl-LiBr-NaF-KF (425 °C, 3.11 S cm -1), LiCl-LiBr-NaCl-KCl (420 °C, 2.73 S cm -1), and LiCl-LiBr-NaBr-KBr (420 °C, 2.76 S cm -1) meet our targets for both melting point (350-430 °C) and ionic conductivity (2.0 S cm -1 and higher at 500 °C). A single cell using the newly developed LiCl-LiBr-NaCl-KCl molten salt as an electrolyte was prepared, and the DC-IR of the cell decreased by 20% than that of a single cell using the conventional LiCl-KCl molten salt. It was therefore concluded that the use of new quaternary molten salt systems can improve the discharge rate-capability in practical battery applications because of their high ionic conductivities.

Characteristics of solidified products containing radioactive molten salt waste.

PubMed

Park, Hwan-Seo; Kim, In-Tae; Cho, Yong-Zun; Eun, Hee-Chul; Kim, Joon-Hyung

2007-11-01

The molten salt waste from a pyroprocess to recover uranium and transuranic elements is one of the problematic radioactive wastes to be solidified into a durable wasteform for its final disposal. By using a novel method, named as the GRSS (gel-route stabilization/solidification) method, a molten salt waste was treated to produce a unique wasteform. A borosilicate glass as a chemical binder dissolves the silicate compounds in the gel products to produce one amorphous phase while most of the phosphates are encapsulated by the vitrified phase. Also, Cs in the gel product is preferentially situated in the silicate phase, and it is vitrified into a glassy phase after a heat treatment. The Sr-containing phase is mainly phosphate compounds and encapsulated by the glassy phase. These phenomena could be identified by the static and dynamic leaching test that revealed a high leach resistance of radionuclides. The leach rates were about 10(-3) - 10(-2) g/m2 x day for Cs and 10(-4) - 10(-3) g/m2 x day for Sr, and the leached fractions of them were predicted to be 0.89% and 0.39% at 900 days, respectively. This paper describes the characteristics of a unique wasteform containing a molten salt waste and provides important information on a newly developed immobilization technology for salt wastes, the GRSS method.

Compatibility of molten salts with advanced solar dynamic receiver materials

NASA Technical Reports Server (NTRS)

Jaworske, D. A.; Perry, W. D.

1989-01-01

Metal-coated graphite fibers are being considered as a thermal conductivity enhancement filler material for molten salts in solar dynamic thermal energy storage systems. The successful metal coating chosen for this application must exhibit acceptable wettability and must be compatible with the molten salt environment. Contact angle values between molten lithium fluoride and several metal, metal fluoride, and metal oxide substrates have been determined at 892 C using a modification of the Wilhelmy plate technique. Reproducible contact angles with repeated exposure to the molten LiF indicated compatibility.

Corrosion Behavior of Alloys in Molten Fluoride Salts

NASA Astrophysics Data System (ADS)

Zheng, Guiqiu

The molten fluoride salt-cooled high-temperature nuclear reactor (FHR) has been proposed as a candidate Generation IV nuclear reactor. This reactor combines the latest nuclear technology with the use of molten fluoride salt as coolant to significantly enhance safety and efficiency. However, an important challenge in FHR development is the corrosion of structural materials in high-temperature molten fluoride salt. The structural alloys' degradation, particularly in terms of chromium depletion, and the molten salt chemistry are key factors that impact the lifetime of nuclear reactors and the development of future FHR designs. In support of materials development for the FHR, the nickel base alloy of Hastelloy N and iron-chromium base alloy 316 stainless steel are being actively considered as critical structural alloys. Enriched 27LiF-BeF2 (named as FLiBe) is a promising coolant for the FHR because of its neutronic properties and heat transfer characteristics while operating at atmospheric pressure. In this study, the corrosion behavior of Ni-5Cr and Ni-20Cr binary model alloys, and Hastelloy N and 316 stainless steel in molten FLiBe with and without graphite were investigated through various microstructural analyses. Based on the understanding of the corrosion behavior and data of above four alloys in molten FLiBe, a long-term corrosion prediction model has been developed that is applicable specifically for these four materials in FLiBe at 700ºC. The model uses Cr concentration profile C(x, t) as a function of corrosion distance in the materials and duration fundamentally derived from the Fick's diffusion laws. This model was validated with reasonable accuracy for the four alloys by fitting the calculated profiles with experimental data and can be applied to evaluate corrosion attack depth over the long-term. The critical constant of the overall diffusion coefficient (Deff) in this model can be quickly calculated from the experimental measurement of alloys' weight

Rotating cathode device for molten salt bath

NASA Astrophysics Data System (ADS)

1983-11-01

The invention relates to a rotating cathode device for molten salt baths used to prepare metallic titanium or aluminum and the like by electrolysis of molten salts. The rotating cathode device is described. It is a cyclindrical cathode mounted on a rotating spindle, made of a lightweight material and mounted in such a way as to avoid thermal strain between the rotational shaft and the cylindrical cathode. At least one of the upper and lower ends of the cylindrical cathode are closed by a cap and a seal consisting of an inorganic fiber composite in the area between the cap and the cathode.

Molten salt-directed synthesis method for LiMn2O4 nanorods as a cathode material for a lithium-ion battery with superior cyclability

NASA Astrophysics Data System (ADS)

Kebede, Mesfin A.; Ozoemena, Kenneth I.

2017-02-01

A molten salt synthesis technique has been used to prepare nanorods of Mn2O3 and single-crystal LiMn2O4 nanorods cathode material with superior capacity retention. The molten salt-directed synthesis involved the use of NaCl as the eutectic melt. The as-synthesized LiMn2O4 nanorods cathode material showed superior electrochemical performance compared to the LiMn2O4 sample obtained via the solid state method. The as-synthesized LiMn2O4 nanorods maintained more than 95% of the initial discharge capacity of 107 mA h g-1 over 100 cycles at a rate of 0.1 C, whereas the LiMn2O4 sample synthesized using the solid state reaction method maintained 88% of the initial discharge capacity of 98 mA h g-1 over 100 cycles at a rate of 0.1 C. Compared to the literature, the molten salt-directed method for the preparation of high-performance LiMn2O4 is simpler and less expensive, with greater potential for industrial scale-up.

Novel Molten Salts Thermal Energy Storage for Concentrating Solar Power Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, Ramana G.

2013-10-23

The explicit UA program objective is to develop low melting point (LMP) molten salt thermal energy storage media with high thermal energy storage density for sensible heat storage systems. The novel Low Melting Point (LMP) molten salts are targeted to have the following characteristics: 1. Lower melting point (MP) compared to current salts (<222ºC) 2. Higher energy density compared to current salts (>300 MJ/m3) 3. Lower power generation cost compared to current salt In terms of lower power costs, the program target the DOE's Solar Energy Technologies Program year 2020 goal to create systems that have the potential to reducemore » the cost of Thermal Energy Storage (TES) to less than $15/kWh-th and achieve round trip efficiencies greater than 93%. The project has completed the experimental investigations to determine the thermo-physical, long term thermal stability properties of the LMP molten salts and also corrosion studies of stainless steel in the candidate LMP molten salts. Heat transfer and fluid dynamics modeling have been conducted to identify heat transfer geometry and relative costs for TES systems that would utilize the primary LMP molten salt candidates. The project also proposes heat transfer geometry with relevant modifications to suit the usage of our molten salts as thermal energy storage and heat transfer fluids. The essential properties of the down-selected novel LMP molten salts to be considered for thermal storage in solar energy applications were experimentally determined, including melting point, heat capacity, thermal stability, density, viscosity, thermal conductivity, vapor pressure, and corrosion resistance of SS 316. The thermodynamic modeling was conducted to determine potential high temperature stable molten salt mixtures that have thermal stability up to 1000 °C. The thermo-physical properties of select potential high temperature stable (HMP) molten salt mixtures were also experimentally determined. All the salt mixtures align with

Separation of actinides from lanthanides utilizing molten salt electrorefining

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grimmett, D.L.; Fusselman, S.P.; Roy, J.J.

1996-10-01

TRUMP-S (TRansUranic Management through Pyropartitioning Separation) is a pyrochemical process being developed to separate actinides form fission products in nuclear waste. A key process step involving molten salt electrorefining to separate actinides from lanthanides has been studied on a laboratory scale. Electrorefining of U, Np, Pu, Am, and lanthanide mixtures from molten cadmium at 450 C to a solid cathode utilizing a molten chloride electrolyte resulted in > 99% removal of actinides from the molten cadmium and salt phases. Removal of the last few percent of actinides is accompanied by lowered cathodic current efficiency and some lanthanide codeposition. Actinide/lanthanide separationmore » ratios on the cathode are ordered U > Np > Pu > Am and are consistent with predictions based on equilibrium potentials.« less

Candidate molten salt investigation for an accelerator driven subcritical core

NASA Astrophysics Data System (ADS)

Sooby, E.; Baty, A.; Beneš, O.; McIntyre, P.; Pogue, N.; Salanne, M.; Sattarov, A.

2013-09-01

We report a design for accelerator-driven subcritical fission in a molten salt core (ADSMS) that utilizes a fuel salt composed of NaCl and transuranic (TRU) chlorides. The ADSMS core is designed for fast neutronics (28% of neutrons >1 MeV) to optimize TRU destruction. The choice of a NaCl-based salt offers benefits for corrosion, operating temperature, and actinide solubility as compared with LiF-based fuel salts. A molecular dynamics (MD) code has been used to estimate properties of the molten salt system which are important for ADSMS design but have never been measured experimentally. Results from the MD studies are reported. Experimental measurements of fuel salt properties and studies of corrosion and radiation damage on candidate metals for the core vessel are anticipated. A special thanks is due to Prof. Paul Madden for introducing the ADSMS group to the concept of using the molten salt as the spallation target, rather than a conventional heavy metal spallation target. This feature helps to optimize this core as a Pu/TRU burner.

Liquid fuel molten salt reactors for thorium utilization

DOE PAGES

Gehin, Jess C.; Powers, Jeffrey J.

2016-04-08

Molten salt reactors (MSRs) represent a class of reactors that use liquid salt, usually fluoride- or chloride-based, as either a coolant with a solid fuel (such as fluoride salt-cooled high temperature reactors) or as a combined coolant and fuel with fuel dissolved in a carrier salt. For liquid-fuelled MSRs, the salt can be processed online or in a batch mode to allow for removal of fission products as well as introduction of fissile fuel and fertile materials during reactor operation. The MSR is most commonly associated with the 233U/thorium fuel cycle, as the nuclear properties of 233U combined with themore » online removal of parasitic absorbers allow for the ability to design a thermal-spectrum breeder reactor; however, MSR concepts have been developed using all neutron energy spectra (thermal, intermediate, fast, and mixed-spectrum zoned concepts) and with a variety of fuels including uranium, thorium, plutonium, and minor actinides. Early MSR work was supported by a significant research and development (R&D) program that resulted in two experimental systems operating at ORNL in the 1960s, the Aircraft Reactor Experiment and the Molten Salt Reactor Experiment. Subsequent design studies in the 1970s focusing on thermal-spectrum thorium-fueled systems established reference concepts for two major design variants: (1) a molten salt breeder reactor (MSBR), with multiple configurations that could breed additional fissile material or maintain self-sustaining operation; and (2) a denatured molten salt reactor (DMSR) with enhanced proliferation-resistance. T MSRs has been selected as one of six most promising Generation IV systems and development activities have been seen in fast-spectrum MSRs, waste-burning MSRs, MSRs fueled with low-enriched uranium (LEU), as well as more traditional thorium fuel cycle-based MSRs. This study provides an historical background of MSR R&D efforts, surveys and summarizes many of the recent development, and provides analysis comparing

Chronopotentiometry of refractory metals, actinides and oxyanions in molten salts: A review

NASA Technical Reports Server (NTRS)

Bansal, Narottam P.

1992-01-01

The applications of chronopotentiometry to the study of electrochemical behavior of three technologically important areas of refractory metals, actinides, and oxyanions in molten salts are critically reviewed. Chronopotentiometry is a very versatile diagnostic tool to understand the reaction mechanism of the electrode processes for the electrochemical reduction/oxidation of these electroactive species in molten salt solutions. Well adherent, compact, and uniformly thick coatings of refractory metals may be electrodeposited from their solutions in molten salts.

New molten salt systems for high-temperature molten salt batteries: LiF-LiCl-LiBr-based quaternary systems

NASA Astrophysics Data System (ADS)

Fujiwara, Syozo; Inaba, Minoru; Tasaka, Akimasa

To develop novel multi-component molten salt systems more effectively, we developed a simulative technique using the CALPHAD (Calculation of Phase Diagram and Thermodynamics) method to estimate the ionic conductivity and the melting point. The validity of this new simulative technique was confirmed by comparing the simulated ionic conductivities and melting points of typical high-temperature molten salts, such as LiF-LiCl-LiBr, LiF-LiBr-KBr, LiCl-LiBr-KBr, and LiCl-LiBr-LiI, with those reported data in the literature or experimentally obtained. This simulative technique was used to develop new quaternary molten salt systems for use as electrolytes in high-temperature molten salt batteries (called thermal batteries). The targets of the ionic conductivity and the melting point were set at 2.0 S cm -1 and higher at 500 °C, and in the range of 350-430 °C, respectively, to replace the LiCl-KCl system (1.85 S cm -1 at 500 °C) within the conventional design of the heat generation system for thermal batteries. Using the simulative method, six kinds of novel quaternary systems, LiF-LiCl-LiBr-MX (M = Na and K; X = F, Cl, and Br), which contain neither environmentally instable anions such as iodides nor expensive cations such as Rb + and Cs +, were proposed. Experimental results showed that the LiF-LiCl-LiBr-0.10NaX (X = Cl and Br) and LiF-LiCl-LiBr-0.10KX (X = F, Cl, and Br) systems meet our targets of both the ionic conductivity and the melting point.

Oxidation of hydrogen halides to elemental halogens with catalytic molten salt mixtures

DOEpatents

Rohrmann, Charles A.

1978-01-01

A process for oxidizing hydrogen halides by means of a catalytically active molten salt is disclosed. The subject hydrogen halide is contacted with a molten salt containing an oxygen compound of vanadium and alkali metal sulfates and pyrosulfates to produce an effluent gas stream rich in the elemental halogen. The reduced vanadium which remains after this contacting is regenerated to the active higher valence state by contacting the spent molten salt with a stream of oxygen-bearing gas.

Solar gasification of biomass: design and characterization of a molten salt gasification reactor

NASA Astrophysics Data System (ADS)

Hathaway, Brandon Jay

The design and implementation of a prototype molten salt solar reactor for gasification of biomass is a significant milestone in the development of a solar gasification process. The reactor developed in this work allows for 3 kWth operation with an average aperture flux of 1530 suns at salt temperatures of 1200 K with pneumatic injection of ground or powdered dry biomass feedstocks directly into the salt melt. Laboratory scale experiments in an electrically heated reactor demonstrate the benefits of molten salt and the data was evaluated to determine the kinetics of pyrolysis and gasification of biomass or carbon in molten salt. In the presence of molten salt overall gas yields are increased by up to 22%; pyrolysis rates double due to improved heat transfer, while carbon gasification rates increase by an order of magnitude. Existing kinetic models for cellulose pyrolysis fit the data well, while carbon gasification in molten salt follows kinetics modeled with a 2/3 order shrinking-grain model with a pre-exponential factor of 1.5*106 min-1 and activation energy of 158 kJ/mol. A reactor concept is developed based around a concentric cylinder geometry with a cavity-style solar receiver immersed within a volume of molten carbonate salt. Concentrated radiation delivered to the cavity is absorbed in the cavity walls and transferred via convection to the salt volume. Feedstock is delivered into the molten salt volume where biomass gasification reactions will be carried out producing the desired product gas. The features of the cavity receiver/reactor concept are optimized based on modeling of the key physical processes. The cavity absorber geometry is optimized according to a parametric survey of radiative exchange using a Monte Carlo ray tracing model, resulting in a cavity design that achieves absorption efficiencies of 80%-90%. A parametric survey coupling the radiative exchange simulations to a CFD model of molten salt natural convection is used to size the annulus

Resistance of Nanostructured Environmental Barrier Coatings to the Movement of Molten Salts

NASA Astrophysics Data System (ADS)

Rao, S.; Frederick, L.; McDonald, A.

2012-09-01

Corrosion of components in a recovery boiler is a major problem faced by the pulp and paper industry. The superheater tubes become severely corroded due to the presence of sulfidic gases in the boiler and molten salts which are deposited on the surface of the tubes. As a result, the boiler must be decommissioned for expensive maintenance and repairs. Yttria-stabilized zirconia (YSZ) coatings have been shown to provide corrosion resistance when applied on gas turbines operating at high temperatures. Air plasma-sprayed YSZ environmental barrier coatings on Type 309 stainless steel were exposed to three different corrosive environments: Test A—600 °C, salt vapors, flue gases, 168 h; Test B—600 °C, molten salt, air, 168 h; and Test C—600 °C, molten salt, flue gases, 168 h. Two different types of YSZ coatings—conventional YSZ and nanostructured YSZ—were tested to study their resistance to corrosion and molten salt penetration. The performances of both types of coatings were evaluated, and a comparative study was conducted. It was found that the nanostructured YSZ samples protected the stainless steel substrate better than their conventional counterparts. This superior performance was attributed to the presence of semi-molten nano-agglomerates present in the coating microstructure, which acted as collection points for the penetrating molten salts.

A Theory of Electrical Conductivity of Pseudo-Binary Equivalent Molten Salt

NASA Astrophysics Data System (ADS)

Matsunaga, Shigeki; Koishi, Takahiro; Tamaki, Shigeru

2008-02-01

Many years ago, Sundheim proposed the "universal golden rule" by experiments, i.e. the ratio of the partial ionic conductivities in molten binary salt is equal to the inverse mass ratio of each ions, σ+/σ- = m-/m-. In the previous works, we have proved this relation by the theory using Langevin equation, and by molecular dynamics simulations (MD). In this study, the pseudo binary molten salt NaCl-KCl system is investigated in the same theoretical framework as previous works as the serial work in molten salts. The MD results are also reported in connection with the theoretical analysis.

Molten salt based nanofluids based on solar salt and alumina nanoparticles: An industrial approach

NASA Astrophysics Data System (ADS)

Muñoz-Sánchez, Belén; Nieto-Maestre, Javier; Guerreiro, Luis; Julia, José Enrique; Collares-Pereira, Manuel; García-Romero, Ana

2017-06-01

Thermal Energy Storage (TES) and its associated dispatchability is extremely important in Concentrated Solar Power (CSP) plants since it represents the main advantage of CSP technology in relation to other renewable energy sources like photovoltaic (PV). Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 600°C. Their main problems are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve the thermal properties of molten salts is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. Additionally, the use of molten salt based nanofluids as TES materials and Heat Transfer Fluid (HTF) has been attracting great interest in recent years. The addition of tiny amounts of nanoparticles to the base salt can improve its specific heat as shown by different authors1-3. The application of these nano-enhanced materials can lead to important savings on the investment costs in new TES systems for CSP plants. However, there is still a long way to go in order to achieve a commercial product. In this sense, the improvement of the stability of the nanofluids is a key factor. The stability of nanofluids will depend on the nature and size of the nanoparticles, the base salt and the interactions between them. In this work, Solar Salt (SS) commonly used in CSP plants (60% NaNO3 + 40% KNO3 wt.) was doped with alumina nanoparticles (ANPs) at a solid mass concentration of 1% wt. at laboratory scale. The tendency of nanoparticles to agglomeration and sedimentation is tested in the molten state by analyzing their size and concentration through the time. The specific heat of the nanofluid at 396 °C (molten state) is measured at different times (30 min, 1 h, 5 h). Further research is needed to understand the mechanisms of agglomeration. A good understanding of the interactions between the nanoparticle surface and the ionic media would provide

Castable cements to prevent corrosion of metals in molten salts

DOE PAGES

Gomez-Vidal, Judith C.; Morton, E.

2016-04-22

Castable cements on metals form a protective barrier that is able to prevent permeation of molten salts towards metallic surfaces. Silica-based castable cements are capable of protecting containment metallic alloys from the corrosive attack of molten chlorides at temperatures as high as 650 °C. Boron nitride (BN) blocking the pores in the cured cement prevents permeation of the molten chloride towards the metal surface. The cements tested are not chemically stable in molten carbonates, because the bonding components dissolved into molten carbonates salt. The corrosion rate is 7.72±0.32 mm/year for bare stainless steel 347 in molten eutectic NaCl – 65.58more » wt% LiCl at 650 °C, which is the baseline used for determining how well the cement protects the metallic surfaces from corrosion. In particular the metal fully encapsulated with Aremco 645-N with pores filled with boron nitride immersed in molten eutectic NaCl – 65.58 wt% LiCl at 650 °C shows a corrosion rate of 9E-04 mm/year. Here, the present study gives initial corrosion rates. Long-term tests are required to determine if Aremco 645-N with BN coating on metal has long term chemical stability for blocking salt permeation through coating pores.« less

Reversible electro-optic device employing aprotic molten salts and method

DOEpatents

Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM; Burrell, Anthony K [Los Alamos, NM; Hall, Simon B [Palmerston North, NZ

2008-01-08

A single-compartment reversible mirror device having a solution of aprotic molten salt, at least one soluble metal-containing species comprising metal capable of being electrodeposited, and at least one anodic compound capable of being oxidized was prepared. The aprotic molten salt is liquid at room temperature and includes lithium and/or quaternary ammonium cations, and anions selected from trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). A method for preparing substantially pure molten salts is also described.

Reversible Electro-Optic Device Employing Aprotic Molten Salts And Method

DOEpatents

Warner, Benjamin P.; McCleskey, T. Mark; Burrell, Anthony K.; Hall, Simon B.

2005-03-01

A single-compartment reversible mirror device having a solution of aprotic molten salt, at least one soluble metal-containing species comprising metal capable of being electrodeposited, and at least one anodic compound capable of being oxidized was prepared. The aprotic molten salt is liquid at room temperature and includes lithium and/or quaternary ammonium cations, and anions selected from trifluoromethylsulfonate (CF.sub.3 SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3 SO.sub.2).sub.2 N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3 CF.sub.2 SO.sub.2).sub.2 N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3 SO.sub.2).sub.3 C.sup.-). A method for preparing substantially pure molten salts is also described.

Injector nozzle for molten salt destruction of energetic waste materials

DOEpatents

Brummond, William A.; Upadhye, Ravindra S.

1996-01-01

An injector nozzle has been designed for safely injecting energetic waste materials, such as high explosives, propellants, and rocket fuels, into a molten salt reactor in a molten salt destruction process without premature detonation or back burn in the injection system. The energetic waste material is typically diluted to form a fluid fuel mixture that is injected rapidly into the reactor. A carrier gas used in the nozzle serves as a carrier for the fuel mixture, and further dilutes the energetic material and increases its injection velocity into the reactor. The injector nozzle is cooled to keep the fuel mixture below the decomposition temperature to prevent spontaneous detonation of the explosive materials before contact with the high-temperature molten salt bath.

Injector nozzle for molten salt destruction of energetic waste materials

DOEpatents

Brummond, W.A.; Upadhye, R.S.

1996-02-13

An injector nozzle has been designed for safely injecting energetic waste materials, such as high explosives, propellants, and rocket fuels, into a molten salt reactor in a molten salt destruction process without premature detonation or back burn in the injection system. The energetic waste material is typically diluted to form a fluid fuel mixture that is injected rapidly into the reactor. A carrier gas used in the nozzle serves as a carrier for the fuel mixture, and further dilutes the energetic material and increases its injection velocity into the reactor. The injector nozzle is cooled to keep the fuel mixture below the decomposition temperature to prevent spontaneous detonation of the explosive materials before contact with the high-temperature molten salt bath. 2 figs.

Chemical interactions and thermodynamic studies in aluminum alloy/molten salt systems

NASA Astrophysics Data System (ADS)

Narayanan, Ramesh

The recycling of aluminum and aluminum alloys such as Used Beverage Container (UBC) is done under a cover of molten salt flux based on (NaCl-KCl+fluorides). The reactions of aluminum alloys with molten salt fluxes have been investigated. Thermodynamic calculations are performed in the alloy/salt flux systems which allow quantitative predictions of the equilibrium compositions. There is preferential reaction of Mg in Al-Mg alloy with molten salt fluxes, especially those containing fluorides like NaF. An exchange reaction between Al-Mg alloy and molten salt flux has been demonstrated. Mg from the Al-Mg alloy transfers into the salt flux while Na from the salt flux transfers into the metal. Thermodynamic calculations indicated that the amount of Na in metal increases as the Mg content in alloy and/or NaF content in the reacting flux increases. This is an important point because small amounts of Na have a detrimental effect on the mechanical properties of the Al-Mg alloy. The reactions of Al alloys with molten salt fluxes result in the formation of bluish purple colored "streamers". It was established that the streamer is liquid alkali metal (Na and K in the case of NaCl-KCl-NaF systems) dissipating into the melt. The melts in which such streamers were observed are identified. The metal losses occurring due to reactions have been quantified, both by thermodynamic calculations and experimentally. A computer program has been developed to calculate ternary phase diagrams in molten salt systems from the constituting binary phase diagrams, based on a regular solution model. The extent of deviation of the binary systems from regular solution has been quantified. The systems investigated in which good agreement was found between the calculated and experimental phase diagrams included NaF-KF-LiF, NaCl-NaF-NaI and KNOsb3-TINOsb3-LiNOsb3. Furthermore, an insight has been provided on the interrelationship between the regular solution parameters and the topology of the phase

Electrochemical Dissolution of Tungsten Carbide in NaCl-KCl-Na2WO4 Molten Salt

NASA Astrophysics Data System (ADS)

Zhang, Liwen; Nie, Zuoren; Xi, Xiaoli; Ma, Liwen; Xiao, Xiangjun; Li, Ming

2018-02-01

Tungsten carbide was utilized as anode to extract tungsten in a NaCl-KCl-Na2WO4 molten salt, and the electrochemical dissolution was investigated. Although the molten salt electrochemical method is a short process method of tungsten extraction from tungsten carbide in one step, the dissolution efficiency and current efficiency are quite low. In order to improve the dissolution rate and current efficiency, the sodium tungstate was added as the active substance. The dissolution rate, the anode current efficiency, and the cathode current efficiency were calculated with different contents of sodium tungstate addition. The anodes prior to and following the reaction, as well as the product, were analyzed through X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. The results demonstrated that the sodium tungstate could improve the dissolution rate and the current efficiency, due to the addition of sodium tungstate decreasing the charge transfer resistance in the electrolysis system. Due to the fact that the addition of sodium tungstate could remove the carbon during electrolysis, pure tungsten powders with 100 nm diameter were obtained when the content of sodium tungstate was 1.0 pct.

Characteristic of molten fluoride salt system LiF-BeF2 (Flibe) and LiF-NaF-KF (Flinak) as coolant and fuel carrier in molten salt reactor (MSR)

NASA Astrophysics Data System (ADS)

Bahri, Che Nor Aniza Che Zainul; Al-Areqi, Wadee'ah Mohd; Ruf, Mohd'Izzat Fahmi Mohd; Majid, Amran Ab.

2017-01-01

Interest of fluoride salts have recently revived due to the high temperature application in nuclear reactors. Molten Salt Reactor (MSR) was designed to operate at high temperature in range 700 - 800°C and its fuel is dissolved in a circulating molten fluoride salt mixture. Molten fluoride salts are stable at high temperature, have good heat transfer properties and can dissolve high concentration of actinides and fission product. The aim of this paper was to discuss the physical properties (melting temperature, density and heat capacity) of two systems fluoride salt mixtures i.e; LiF-BeF2 (Flibe) and LiF-NaF-KF (Flinak) in terms of their application as coolant and fuel solvent in MSR. Both of these salts showed almost same physical properties but different applications in MSR. The advantages and the disadvantages of these fluoride salt systems will be discussed in this paper.

Progress in modeling solidification in molten salt coolants

NASA Astrophysics Data System (ADS)

Tano, Mauricio; Rubiolo, Pablo; Doche, Olivier

2017-10-01

Molten salts have been proposed as heat carrier media in the nuclear and concentrating solar power plants. Due to their high melting temperature, solidification of the salts is expected to occur during routine and accidental scenarios. Furthermore, passive safety systems based on the solidification of these salts are being studied. The following article presents new developments in the modeling of eutectic molten salts by means of a multiphase, multicomponent, phase-field model. Besides, an application of this methodology for the eutectic solidification process of the ternary system LiF-KF-NaF is presented. The model predictions are compared with a newly developed semi-analytical solution for directional eutectic solidification at stable growth rate. A good qualitative agreement is obtained between the two approaches. The results obtained with the phase-field model are then used for calculating the homogenized properties of the solid phase distribution. These properties can then be included in a mixture macroscale model, more suitable for industrial applications.

Phenomena Important in Molten Salt Reactor Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diamond, David J.; Brown, Nicholas R.; Denning, Richard

The U.S. Nuclear Regulatory Commission (NRC) is preparing for the future licensing of advanced reactors that will be very different from current light water reactors. Part of the NRC preparation strategy is to identify the simulation tools that will be used for confirmatory safety analysis of normal operation and abnormal situations in those reactors. This report advances that strategy for reactors that will use molten salts (MSRs). This includes reactors with the fuel within the salt as well as reactors using solid fuel. Although both types are discussed in this report, the emphasis is on those reactors with liquid fuelmore » because of the perception that solid-fuel MSRs will be significantly easier to simulate. These liquid-fuel reactors include thermal and fast neutron spectrum alternatives. The specific designs discussed in the report are a subset of many designs being considered in the U.S. and elsewhere but they are considered the most likely to submit information to the NRC in the near future. The objective herein, is to understand the design of proposed molten salt reactors, how they will operate under normal or transient/accident conditions, and what will be the corresponding modeling needs of simulation tools that consider neutronics, heat transfer, fluid dynamics, and material composition changes in the molten salt. These tools will enable the NRC to eventually carry out confirmatory analyses that examine the validity and accuracy of applicant’s calculations and help determine the margin of safety in plant design.« less

CO2 decomposition using electrochemical process in molten salts

NASA Astrophysics Data System (ADS)

Otake, Koya; Kinoshita, Hiroshi; Kikuchi, Tatsuya; Suzuki, Ryosuke O.

2012-08-01

The electrochemical decomposition of CO2 gas to carbon and oxygen gas in LiCl-Li2O and CaCl2-CaO molten salts was studied. This process consists of electrochemical reduction of Li2O and CaO, as well as the thermal reduction of CO2 gas by the respective metallic Li and Ca. Two kinds of ZrO2 solid electrolytes were tested as an oxygen ion conductor, and the electrolytes removed oxygen ions from the molten salts to the outside of the reactor. After electrolysis in both salts, the aggregations of nanometer-scale amorphous carbon and rod-like graphite crystals were observed by transmission electron microscopy. When 9.7 %CO2-Ar mixed gas was blown into LiCl-Li2O and CaCl2-CaO molten salts, the current efficiency was evaluated to be 89.7 % and 78.5 %, respectively, by the exhaust gas analysis and the supplied charge. When a solid electrolyte with higher ionic conductivity was used, the current and carbon production became larger. It was found that the rate determining step is the diffusion of oxygen ions into the ZrO2 solid electrolyte.

Destruction of decabromodiphenyl ether (BDE-209) in a ternary carbonate molten salt reactor.

PubMed

Yao, Zhi-tong; Li, Jin-hui; Zhao, Xiang-yang

2013-09-30

Soil contamination by PBDEs has become a significant environmental concern and requires appropriate remediation technologies. In this study, the destruction of decabromodiphenyl ether (BDE-209) in a ternary molten salt (Li, Na, K)2 CO3 reactor was evaluated. The effects of reaction temperature, additive amount of BDE-209 and salt mixture, on off-gas species, were investigated. The salt mixture after reaction was characterized by XRD analysis and a reaction pathway proposed. The results showed that the amounts of C2H6, C2H4, C4H8 and CH4 in the off-gas decreased with increases in temperature, while the CO2 level increased. When the reaction temperature reached 750 °C, incomplete combustion products (PICs) were no longer detected. Increasing BDE-209 loading was not helpful for the reaction, as more PICs were produced. Larger amounts of salt mixture were helpful for the reaction and PICs were not observed with the mole ratio 1: 2000 of BDE-209 to carbonate melt. XRD analysis confirmed the capture of bromine in BDE-209 by the molten salt. Copyright © 2013 Elsevier Ltd. All rights reserved.

Nickel-plating for active metal dissolution resistance in molten fluoride salts

NASA Astrophysics Data System (ADS)

Olson, Luke; Sridharan, Kumar; Anderson, Mark; Allen, Todd

2011-04-01

Ni electroplating of Incoloy-800H was investigated with the goal of mitigating Cr dissolution from this alloy into molten 46.5%LiF-11.5%NaF-42%KF eutectic salt, commonly referred to as FLiNaK. Tests were conducted in graphite crucibles at a molten salt temperature of 850 °C. The crucible material graphite accelerates the corrosion process due to the large activity difference between the graphite and the alloy. For the purposes of providing a baseline for this study, un-plated Incoloy-800H and a nearly pure Ni-alloy, Ni-201 were also tested. Results indicate that Ni-plating has the potential to significantly improve the corrosion resistance of Incoloy-800H in molten fluoride salts. Diffusion of Cr from the alloy through the Ni-plating does occur and if the Ni-plating is thin enough this Cr eventually dissolves into the molten salt. The post-corrosion test microstructure of the Ni-plating, particularly void formation was also observed to depend on the plating thickness. Diffusion anneals in a helium environment of Ni-plated Incoloy-800H and an Fe-Ni-Cr model alloy were also investigated to understand Cr diffusion through the Ni-plating. Further enhancements in the efficacy of the Ni-plating as a protective barrier against Cr dissolution from the alloy into molten fluoride salts can be achieved by thermally forming a Cr 2O 3 barrier film on the surface of the alloy prior to Ni electroplating.

Materials Testing for an Accelerator-Driven Subcritical Molten Salt Fission System: A look at the Materials Science of Molten Salt Corrosion

NASA Astrophysics Data System (ADS)

Sooby, Elizabeth; Balachandran, Shreyas; Foley, David; Hartwig, Karl; McIntyre, Peter; Phongikaroon, Supathorn; Pogue, Nathaniel; Simpson, Michael; Tripathy, Prabhat

2011-10-01

For an accelerator-driven subcritical molten salt fission core to survive its 50+ year fuel life, the primary vessel, heat exchanger, and various internal components must be made of materials that resist corrosion and radiation damage in a high-temperature environment, (500-800 C). An experimental study of the corrosion behavior of candidate metals in contact with molten salt is being conducted at the Center for Advanced Energy Studies. Initial experiments have been run on Nb, Ta, Ni, two zirconium alloys, Hastelloy-N, and a series of steel alloys to form a base line for corrosion in both chloride and bromide salt. Metal coupons were immersed in LiCl-KCl or LiBr-KBr at 700 C in an inert-atmosphere. Salt samples were extracted on a time schedule over a 24-hr period. The samples were analyzed using inductively coupled plasma-mass spectrometry to determine concentrations of metals from corrosion. Preliminary results will be presented.

A Facile Molten-Salt Route for Large-Scale Synthesis of NiFe2O4 Nanoplates with Enhanced Lithium Storage Capability.

PubMed

Huang, Gang; Du, Xinchuan; Zhang, Feifei; Yin, Dongming; Wang, Limin

2015-09-28

Binary metal oxides have been deemed as a promising class of electrode materials for high-performance lithium ion batteries owing to their higher conductivity and electrochemical activity than corresponding monometal oxides. Here, NiFe2O4 nanoplates consisting of nanosized building blocks have been successfully fabricated by a facile, large-scale NaCl and KCl molten-salt route, and the changes in the morphology of NiFe2O4 as a function of the molten-salt amount have been systemically investigated. The results indicate that the molten-salt amount mainly influences the diameter and thickness of the NiFe2O4 nanoplates as well as the morphology of the nanosized building blocks. Cyclic voltammetry (CV) and galvanostatic charge-discharge measurements have been conducted to evaluate the lithium storage properties of the NiFe2O4 nanoplates prepared with a Ni(NO3)2/Fe(NO3)3/KCl/NaCl molar ratio of 1:2:20:60. A high reversible capacity of 888 mAh g(-1) is delivered over 100 cycles at a current density of 100 mA g(-1). Even at a current density of 5000 mA g(-1) , the discharge capacity could still reach 173 mAh g(-1). Such excellent electrochemical performances of the NiFe2O4 nanoplates are contributed to the short Li(+) diffusion distance of the nanosized building blocks and the synergetic effect of the Ni(2+) and Fe(3+) ions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method of removal of heavy metal from molten salt in IFR fuel pyroprocessing

DOEpatents

Gay, Eddie C.

1995-01-01

An electrochemical method of separating heavy metal values from a radioactive molten salt including Li halide at temperatures of about 500.degree. C. The method comprises positioning a solid Li--Cd alloy anode in the molten salt containing the heavy metal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavy metal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavy metals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode.

Corrosion of 316 stainless steel in high temperature molten Li2BeF4 (FLiBe) salt

NASA Astrophysics Data System (ADS)

Zheng, Guiqiu; Kelleher, Brian; Cao, Guoping; Anderson, Mark; Allen, Todd; Sridharan, Kumar

2015-06-01

In support of structural material development for the fluoride-salt-cooled high-temperature reactor (FHR), corrosion tests of 316 stainless steel were performed in the potential primary coolant, molten Li2BeF4 (FLiBe) at 700 °C for an exposure duration up to 3000 h. Tests were performed in both 316 stainless steel and graphite capsules. Corrosion in both capsule materials occurred by the dissolution of chromium from the stainless steel into the salt which led to the depletion of chromium predominantly along the grain boundaries of the test samples. The samples tested in graphite capsules showed a factor of two greater depth of corrosion attack as measured in terms of chromium depletion, compared to those tested in 316 stainless steel capsules. The samples tested in graphite capsules showed the formation of Cr7C3 particulate phases throughout the depth of the corrosion layer. Samples tested in both types of capsule materials showed the formation of MoSi2 phase due to increased activity of Mo and Si as a result of Cr depletion, and furthermore corrosion promoted the formation of a α-ferrite phase in the near-surface regions of the 316 stainless steel. Based on the corrosion tests, the corrosion attack depth in FLiBe salt was predicted as 17.1 μm/year and 31.2 μm/year for 316 stainless steel tested in 316 stainless steel and in graphite capsules respectively. It is in an acceptable range compared to the Hastelloy-N corrosion in the Molten Salt Reactor Experiment (MSRE) fuel salt.

Effects of Stress on Corrosion in a Molten Salt Environment

NASA Astrophysics Data System (ADS)

Girdzis, Samuel; Manos, Dennis; Cooke, William

Molten salt is often used as a heat transfer and energy storage fluid in concentrating solar power plants. Despite its suitable thermal properties, molten salt can present challenges in terms of corrosion. Previous studies have focused extensively on mass loss due to molten salt-induced corrosion. In contrast, we have investigated how corrosion begins and how it changes the surface of stainless steel. Samples of alloys including 304 and 316 stainless steel were exposed to the industry-standard NaNO3-KNO3 (60%-40% by weight) mixture at temperatures over 500°C and then analyzed using Hirox, SEM, and TOF-SIMS. We compare the corrosion at grain boundaries to that within single grain surfaces, showing the effect of the increased internal stresses and the weakened passivation layer. Also, we have examined the enhanced corrosion of samples under mechanical stress, simulating the effects of thermal stresses in a power plant.

Corrosion Behavior of Alloy 625 in PbSO4-Pb3O4-PbCl2-ZnO-10 Wt Pct CdO Molten Salt Medium

NASA Astrophysics Data System (ADS)

Mohammadi Zahrani, E.; Alfantazi, A. M.

2012-08-01

Corrosion behavior and degradation mechanisms of alloy 625 under a 47.288 PbSO4-12.776 Pb3O4-6.844PbCl2-23.108ZnO-10CdO (wt pct) molten salt mixture under air atmosphere were studied at 873 K, 973 K, and 1073 K (600 °C, 700 °C, and 800 °C). Electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) measurements, and potentiodynamic polarization techniques were used to evaluate the degradation mechanisms and characterize the corrosion behavior of the alloy. Morphology, chemical composition, and phase structure of the corrosion products and surface layers of the corroded specimens were studied by scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) and X-ray map analyses. Results confirmed that during the exposure of alloy 625 to the molten salt, chromium was mainly dissolved through an active oxidation process as CrO3, Cr2O3, and CrNbO4, while nickel dissolved only as NiO in the system. Formation of a porous and nonprotective oxide layer with low resistance is responsible for the weak protective properties of the barrier layer at high temperatures of 973 K and 1073 K (700 °C and 800 °C). There were two kinds of attack for INCONEL 625, including general surface corrosion and pitting. Pitting corrosion occurred due to the breakdown of the initial oxide layer by molten salt dissolution of the oxide or oxide cracking.

Electrical double layers and differential capacitance in molten salts from density functional theory

DOE PAGES

Frischknecht, Amalie L.; Halligan, Deaglan O.; Parks, Michael L.

2014-08-05

Classical density functional theory (DFT) is used to calculate the structure of the electrical double layer and the differential capacitance of model molten salts. The DFT is shown to give good qualitative agreement with Monte Carlo simulations in the molten salt regime. The DFT is then applied to three common molten salts, KCl, LiCl, and LiKCl, modeled as charged hard spheres near a planar charged surface. The DFT predicts strong layering of the ions near the surface, with the oscillatory density profiles extending to larger distances for larger electrostatic interactions resulting from either lower temperature or lower dielectric constant. Inmore » conclusion, overall the differential capacitance is found to be bell-shaped, in agreement with recent theories and simulations for ionic liquids and molten salts, but contrary to the results of the classical Gouy-Chapman theory.« less

The electrochemical reduction processes of solid compounds in high temperature molten salts.

PubMed

Xiao, Wei; Wang, Dihua

2014-05-21

Solid electrode processes fall in the central focus of electrochemistry due to their broad-based applications in electrochemical energy storage/conversion devices, sensors and electrochemical preparation. The electrolytic production of metals, alloys, semiconductors and oxides via the electrochemical reduction of solid compounds (especially solid oxides) in high temperature molten salts has been well demonstrated to be an effective and environmentally friendly process for refractory metal extraction, functional materials preparation as well as spent fuel reprocessing. The (electro)chemical reduction of solid compounds under cathodic polarizations generally accompanies a variety of changes at the cathode/melt electrochemical interface which result in diverse electrolytic products with different compositions, morphologies and microstructures. This report summarizes various (electro)chemical reactions taking place at the compound cathode/melt interface during the electrochemical reduction of solid compounds in molten salts, which mainly include: (1) the direct electro-deoxidation of solid oxides; (2) the deposition of the active metal together with the electrochemical reduction of solid oxides; (3) the electro-inclusion of cations from molten salts; (4) the dissolution-electrodeposition process, and (5) the electron hopping process and carbon deposition with the utilization of carbon-based anodes. The implications of the forenamed cathodic reactions on the energy efficiency, chemical compositions and microstructures of the electrolytic products are also discussed. We hope that a comprehensive understanding of the cathodic processes during the electrochemical reduction of solid compounds in molten salts could form a basis for developing a clean, energy efficient and affordable production process for advanced/engineering materials.

Fission product ion exchange between zeolite and a molten salt

NASA Astrophysics Data System (ADS)

Gougar, Mary Lou D.

The electrometallurgical treatment of spent nuclear fuel (SNF) has been developed at Argonne National Laboratory (ANL) and has been demonstrated through processing the sodium-bonded SNF from the Experimental Breeder Reactor-II in Idaho. In this process, components of the SNF, including U and species more chemically active than U, are oxidized into a bath of lithium-potassium chloride (LiCl-KCl) eutectic molten salt. Uranium is removed from the salt solution by electrochemical reduction. The noble metals and inactive fission products from the SNF remain as solids and are melted into a metal waste form after removal from the molten salt bath. The remaining salt solution contains most of the fission products and transuranic elements from the SNF. One technique that has been identified for removing these fission products and extending the usable life of the molten salt is ion exchange with zeolite A. A model has been developed and tested for its ability to describe the ion exchange of fission product species between zeolite A and a molten salt bath used for pyroprocessing of spent nuclear fuel. The model assumes (1) a system at equilibrium, (2) immobilization of species from the process salt solution via both ion exchange and occlusion in the zeolite cage structure, and (3) chemical independence of the process salt species. The first assumption simplifies the description of this physical system by eliminating the complications of including time-dependent variables. An equilibrium state between species concentrations in the two exchange phases is a common basis for ion exchange models found in the literature. Assumption two is non-simplifying with respect to the mathematical expression of the model. Two Langmuir-like fractional terms (one for each mode of immobilization) compose each equation describing each salt species. The third assumption offers great simplification over more traditional ion exchange modeling, in which interaction of solvent species with each other

Direct reduction processes for titanium oxide in molten salt

NASA Astrophysics Data System (ADS)

Suzuki, Ryosuke O.

2007-02-01

Molten salt electrolysis using CaCl2 is employed to produce pure titanium and its alloys directly from TiO2 and a mixture of elemental oxides, respectively, as an alternate to the Kroll process. This is because CaO, which is a reduction by-product, is highly soluble in CaCl2. Good-quality titanium containing only a small amount of residual oxygen has been successfully produced and scaled to industrial levels. Thermochemical and electrochemical bases are reviewed to optimize the process conditions. Several processes using molten salt are being examined for future progress in titanium processing.

Spectroscopic characterization of nanohydroxyapatite synthesized by molten salt method.

PubMed

Gopi, D; Indira, J; Kavitha, L; Kannan, S; Ferreira, J M F

2010-10-01

Hydroxyapatite (HAP) nanopowders were synthesized by molten salt method at 260 degrees C. The as-prepared powders were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM) and thermo gravimetric analysis (TGA). With the aid of the obtained results the effect of calcining time on the crystallinity, size and morphology of HAP nanopowders is presented. The HAP nanopowders synthesized by molten salt method consist of pure phase of HAP without any impurities and showed the rod-like morphology without detectable decomposition up to 1100 degrees C. Copyright 2010 Elsevier B.V. All rights reserved.

Molten salt synthesis of nanocrystalline phase of high dielectric constant material CaCu3Ti4O12.

PubMed

Prakash, B Shri; Varma, K B R

2008-11-01

Nanocrystalline powders of giant dielectric constant material, CaCu3Ti4O12 (CCTO), have been prepared successfully by the molten salt synthesis (MSS) using KCl at 750 degrees C/10 h, which is significantly lower than the calcination temperature (approximately 1000 degrees C) that is employed to obtain phase pure CCTO in the conventional solid-state reaction route. The water washed molten salt synthesized powder, characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM) confirmed to be a phase pure CCTO associated with approximately 150 nm sized crystallites of nearly spherical shape. The decrease in the formation temperature/duration of CCTO in MSS method was attributed to an increase in the diffusion rate or a decrease in the diffusion length of reacting ions in the molten salt medium. As a consequence of liquid phase sintering, pellets of as-synthesized KCl containing CCTO powder exhibited higher sinterability and grain size than that of KCl free CCTO samples prepared by both MSS method and conventional solid-state reaction route. The grain size and the dielectric constant of KCl containing CCTO ceramics increased with increasing sintering temperature (900 degrees C-1050 degrees C). Indeed the dielectric constants of these ceramics were higher than that of KCl free CCTO samples prepared by both MSS method and those obtained via the solid-state reaction route and sintered at the same temperature. Internal barrier layer capacitance (IBLC) model was invoked to correlate the observed dielectric constant with the grain size in these samples.

Method of removal of heavy metal from molten salt in IFR fuel pyroprocessing

DOEpatents

Gay, E.C.

1995-10-03

An electrochemical method is described for separating heavy metal values from a radioactive molten salt including Li halide at temperatures of about 500 C. The method comprises positioning a solid Li--Cd alloy anode in the molten salt containing the heavy metal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavy metal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavy metals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode. 3 figs.

Numerical study of cold filling and tube deformation in the molten salt receiver

NASA Astrophysics Data System (ADS)

Xu, Tingting; Zhang, Gongchen; Peniguel, Christophe; Liao, Zhirong; Li, Xin; Lu, Jiahui; Wang, Zhifeng

2017-06-01

Molten salt tube cold filling is one way to accelerate the startup of molten salt Concentrated Solar Power (CSP) plant. This practical operation may induce salt solidification and large thermal stress due to tube's large temperature difference. This paper presents the cold filling study and the induced thermal stress quantitatively through simulation approaches. Physical mechanisms and safe working criteria are identified under certain conditions.

Renewing Liquid Fueled Molten Salt Reactor Research and Development

NASA Astrophysics Data System (ADS)

Towell, Rusty; NEXT Lab Team

2016-09-01

Globally there is a desperate need for affordable, safe, and clean energy on demand. More than anything else, this would raise the living conditions of those in poverty around the world. An advanced reactor that utilizes liquid fuel and molten salts is capable of meeting these needs. Although, this technology was demonstrated in the Molten Salt Reactor Experiment (MSRE) at ORNL in the 60's, little progress has been made since the program was cancelled over 40 years ago. A new research effort has been initiated to advance the technical readiness level of key reactor components. This presentation will explain the motivation and initial steps for this new research initiative.

SENER molten salt tower technology. Ouarzazate NOOR III case

NASA Astrophysics Data System (ADS)

Relloso, Sergio; Gutiérrez, Yolanda

2017-06-01

NOOR III 150 MWe project is the evolution of Gemasolar (19.9 MWe) to large scale Molten Salt Tower plants. With more than 5 years of operational experience, Gemasolar lessons learned have been the starting point for the optimization of this technology, considered the leader of potential cost reduction in CSP. In addition, prototypes of plant key components (heliostat and receiver) were manufactured and thoroughly tested before project launch in order to prove the new engineering solutions adopted. The SENER proprietary technology of NOOR III will be applied in the next Molten Salt Tower plants that will follow in other countries, such as South Africa, Chile and Australia.

Al/Cl2 molten salt battery

NASA Technical Reports Server (NTRS)

Giner, J.

1972-01-01

Molten salt battery has been developed with theoretical energy density of 5.2 j/kg (650 W-h/lb). Battery, which operates at 150 C, can be used in primary mode or as rechargeable battery. Battery has aluminum anode and chlorine cathode. Electrolyte is mixture of AlCl3, NaCl, and some alkali metal halide such as KCl.

Preparation of pyrolytic carbon coating on graphite for inhibiting liquid fluoride salt and Xe135 penetration for molten salt breeder reactor

NASA Astrophysics Data System (ADS)

Song, Jinliang; Zhao, Yanling; He, Xiujie; Zhang, Baoliang; Xu, Li; He, Zhoutong; Zhang, DongSheng; Gao, Lina; Xia, Huihao; Zhou, Xingtai; Huai, Ping; Bai, Shuo

2015-01-01

A fixed-bed deposition method was used to prepare rough laminar pyrolytic carbon coating (RLPyC) on graphite for inhibiting liquid fluoride salt and Xe135 penetration during use in molten salt breeder reactor. The RLPyC coating possessed a graphitization degree of 44% and had good contact with graphite substrate. A high-pressure reactor was constructed to evaluate the molten salt infiltration in the isostatic graphite (IG-110, TOYO TANSO CO., LTD.) and RLPyC coated graphite under 1.01, 1.52, 3.04, 5.07 and 10.13 × 105 Pa for 12 h. Mercury injection and molten-salt infiltration experiments indicated the porosity and the salt-infiltration amount of 18.4% and 13.5 wt% under 1.52 × 105 Pa of IG-110, which was much less than 1.2% and 0.06 wt% under 10.13 × 105 Pa of the RLPyC, respectively. A vacuum device was constructed to evaluate the Xe135 penetration in the graphite. The helium diffusion coefficient of RLPyC coated graphite was 2.16 × 10-12 m2/s, much less than 1.21 × 10-6 m2/s of the graphite. Thermal cycle experiment indicated the coatings possessed excellent thermal stability. The coated graphite could effectively inhibit the liquid fluoride salt and Xe135 penetration.

A Molten Salt Lithium-Oxygen Battery.

PubMed

Giordani, Vincent; Tozier, Dylan; Tan, Hongjin; Burke, Colin M; Gallant, Betar M; Uddin, Jasim; Greer, Julia R; McCloskey, Bryan D; Chase, Gregory V; Addison, Dan

2016-03-02

Despite the promise of extremely high theoretical capacity (2Li + O2 ↔ Li2O2, 1675 mAh per gram of oxygen), many challenges currently impede development of Li/O2 battery technology. Finding suitable electrode and electrolyte materials remains the most elusive challenge to date. A radical new approach is to replace volatile, unstable and air-intolerant organic electrolytes common to prior research in the field with alkali metal nitrate molten salt electrolytes and operate the battery above the liquidus temperature (>80 °C). Here we demonstrate an intermediate temperature Li/O2 battery using a lithium anode, a molten nitrate-based electrolyte (e.g., LiNO3-KNO3 eutectic) and a porous carbon O2 cathode with high energy efficiency (∼95%) and improved rate capability because the discharge product, lithium peroxide, is stable and moderately soluble in the molten salt electrolyte. The results, supported by essential state-of-the-art electrochemical and analytical techniques such as in situ pressure and gas analyses, scanning electron microscopy, rotating disk electrode voltammetry, demonstrate that Li2O2 electrochemically forms and decomposes upon cycling with discharge/charge overpotentials as low as 50 mV. We show that the cycle life of such batteries is limited only by carbon reactivity and by the uncontrolled precipitation of Li2O2, which eventually becomes electrically disconnected from the O2 electrode.

Molten salt applications in materials processing

NASA Astrophysics Data System (ADS)

Mishra, Brajendra; Olson, David L.

2005-02-01

The science of molten salt electrochemistry for electrowinning of reactive metals, such as calcium, and its in situ application in pyro-reduction has been described. Calcium electrowinning has been performed in a 5 10 wt% calcium oxide calcium chloride molten salt by the electrolytic dissociation of calcium oxide. This electrolysis requires the use of a porous ceramic sheath around the anode to keep the cathodically deposited calcium and the anodic gases separate. Stainless steel cathode and graphite anode have been used in the temperature range of 850 950 °C. This salt mixture is produced as a result of the direct oxide reduction (DOR) of reactive metal oxides by calcium in a calcium chloride bath. The primary purpose of this process is to recover the expensive calcium reductant and to recycle calcium chloride. Experimental data have been included to justify the suitability as well as limitations of the electrowinning process. Transport of oxygen ions through the sheath is found to be the rate controlling step. Under the constraints of the reactor design, a calcium recovery rate of approx. 150 g/h was achieved. Feasibility of a process to produce metals by pyrometallurgical reduction, using the calcium reductant produced electrolytically within the same reactor, has been shown in a hybrid process. Several processes are currently under investigation to use this electrowon calcium for in situ reduction of metal oxides.

Study on corrosion of metal materials in nitrate molten salts

NASA Astrophysics Data System (ADS)

Zhai, Wei; Yang, Bo; Li, Maodong; Li, Shiping; Xin, Mingliang; Zhang, Shuanghong; Huang, Guojia

2017-01-01

High temperature molten salts as a heat transfer heat storage medium has been more widely used in the field of concentrated solar thermal power generation. In the thermal heat storage system, metal material stability and performance at high temperatures are of one major limitation in increasing this operating temperature. In this paper, study on corrosion of 321H, 304, 316L, P91 metal materials in modified solar two molten salts. The corrosion kinetics of 304, 316L, 321H, P91 metal material in the modified solar two molten salts at 450°C, 500°C is also investigated. Under the same condition it was found that 304, 321H corroded at a rate of 40% less than P91. Spallation of corrosion products was observed on P91 steel, while no obvious observed on other kinds of stainless steel. Corrosion rates of 304, 321H, and 316L slowly increased with temperature. Oxidation mechanisms little varied with temperature. Corrosion products of metal materials observed at 450°C, 500°C were primarily Fe oxide and Fe, Cr oxide.

Performance evaluation of molten salt thermal storage systems

NASA Astrophysics Data System (ADS)

Kolb, G. J.; Nikolai, U.

1987-09-01

The molton salt thermal storage system located at the Central Receiver Test Facility (CRTF) was recently subjected to thermal performance tests. The system is composed of a hot storage tank containing molten nitrate salt at a temperature of 1050 F and a cold tank containing 550 F salt with associated valves and controls. It is rated at 7 MWht and was designed and installed by Martin Marietta Corporation in 1982. The results of these tests were used to accomplish four objectives: (1) to compare the current thermal performance of the system with the performance of the system soon after it was installed, (2) to validate a dynamic computer model of the system, (3) to obtain an estimate of an annual system efficiency for a hypothetical commercial scale 1200 MWht system and (4) to compare the performance of the CRTF system with thermal storage systems developed by the European solar community.

Marangoni convection in molten salts

NASA Astrophysics Data System (ADS)

Cramer, A.; Landgraf, S.; Beyer, E.; Gerbeth, G.

2011-02-01

Marangoni convection is involved in many technological processes. The substances of industrial interest are often governed by diffusive heat transport and their physical modelling is limited with respect to the Prandtl number Pr. The present paper addresses this deficiency. Studies were made on molten salts having Pr values in an intermediate range well below that of the typically employed organics. Since some of the selected species have a relatively high melting point, a high-temperature facility which allows studying thermocapillary convection at temperatures in excess of 1,000°C was built. The results presented here were obtained in a cylindrical geometry, although the equipment that was built is not restricted to this configuration because of its modular construction. Modelled after some applications, the fluid was heated centrically on top. The bulk was embedded in a large thermostatically controlled reservoir so as to establish the lower ambient reference temperature. A characteristic size of the experimental cell was chosen such that, on the one hand, the dynamic Bond number Bo did not become too high; on the other hand, the liquid had to have a certain depth to allow particle image velocimetry. The complicated balance between body forces and thermocapillary forces in the case of intermediate Bo was found to result in a distinct local separation into a bulk motion governed by natural convection with a recirculating Marangoni flow on top. In contrast to low viscosity organics, the vapour pressure of which increases considerably with decreasing Pr, high values of the Marangoni number can be reached. Comparisons of the topology of Marangoni vortices between molten salts with 2.3 ⩽ Pr ⩽ 6.4 and a silicone oil with Pr typically one order of magnitude higher suggest that the regime of non-negligible heat diffusion is entered.

Molten salt electrolyte battery cell with overcharge tolerance

DOEpatents

Kaun, Thomas D.; Nelson, Paul A.

1989-01-01

A molten salt electrolyte battery having an increased overcharge tolerance employs a negative electrode with two lithium alloy phases of different electrochemical potential, one of which allows self-discharge rates which permits battery cell equalization.

Stable colloids in molten inorganic salts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hao; Dasbiswas, Kinjal; Ludwig, Nicholas B.

2017-02-15

A colloidal solution is a homogeneous dispersion of particles or droplets of one phase (solute) in a second, typically liquid, phase (solvent). Colloids are ubiquitous in biological, chemical and technological processes1, 2, homogenizing highly dissimilar constituents. To stabilize a colloidal system against coalescence and aggregation, the surface of each solute particle is engineered to impose repulsive forces strong enough to overpower van der Waals attraction and keep the particles separated from each other2. Electrostatic stabilization3, 4 of charged solutes works well in solvents with high dielectric constants, such as water (dielectric constant of 80). In contrast, colloidal stabilization in solventsmore » with low polarity, such as hexane (dielectric constant of about 2), can be achieved by decorating the surface of each particle of the solute with molecules (surfactants) containing flexible, brush-like chains2, 5. Here we report a class of colloidal systems in which solute particles (including metals, semiconductors and magnetic materials) form stable colloids in various molten inorganic salts. The stability of such colloids cannot be explained by traditional electrostatic and steric mechanisms. Screening of many solute–solvent combinations shows that colloidal stability can be traced to the strength of chemical bonding at the solute–solvent interface. Theoretical analysis and molecular dynamics modelling suggest that a layer of surface-bound solvent ions produces long-ranged charge-density oscillations in the molten salt around solute particles, preventing their aggregation. Colloids composed of inorganic particles in inorganic melts offer opportunities for introducing colloidal techniques to solid-state science and engineering applications.« less

Transient simulation of molten salt central receiver

NASA Astrophysics Data System (ADS)

Doupis, Dimitri; Wang, Chuan; Carcorze-Soto, Jorge; Chen, Yen-Ming; Maggi, Andrea; Losito, Matteo; Clark, Michael

2016-05-01

Alstom is developing concentrated solar power (CSP) utilizing 60/40wt% NaNO3-KNO3 molten salt as the working fluid in a tower receiver for the global renewable energy market. In the CSP power generation cycle, receivers undergo a daily cyclic operation due to the transient nature of solar energy. Development of robust and efficient start-up and shut-down procedures is critical to avoiding component failures due to mechanical fatigue resulting from thermal transients, thus maintaining the performance and availability of the CSP plant. The Molten Salt Central Receiver (MSCR) is subject to thermal transients during normal daily operation, a cycle that includes warmup, filling, operation, draining, and shutdown. This paper describes a study to leverage dynamic simulation and finite element analysis (FEA) in development of start-up, shutdown, and transient operation concepts for the MSCR. The results of the FEA also verify the robustness of the MSCR design to the thermal transients anticipated during the operation of the plant.

Low-temperature synthesis of nanocrystalline ZrC coatings on flake graphite by molten salts

NASA Astrophysics Data System (ADS)

Ding, Jun; Guo, Ding; Deng, Chengji; Zhu, Hongxi; Yu, Chao

2017-06-01

A novel molten salt synthetic route has been developed to prepare nanocrystalline zirconium carbide (ZrC) coatings on flake graphite at 900 °C, using Zr powder and flake graphite as the source materials in a static argon atmosphere, along with molten salts as the media. The effects of different molten salt media, the sintered temperature, and the heat preservation time on the phase and microstructure of the synthetic materials were investigated. The ZrC coatings formed on the flake graphite were uniform and composed of nanosized particles (30-50 nm). With an increase in the reaction temperature, the ZrC nanosized particles were more denser, and the heat preservation time and thickness of the ZrC coating also increased accordingly. Electron microscopy was used to observe the ZrC coatings on the flake graphite, indicating that a "template mechanism" played an important role during the molten salt synthesis.

Effect of Ni-Co Ternary Molten Salt Catalysts on Coal Catalytic Pyrolysis Process

NASA Astrophysics Data System (ADS)

Cui, Xin; Qi, Cong; Li, Liang; Li, Yimin; Li, Song

2017-08-01

In order to facilitate efficient and clean utilization of coal, a series of Ni-Co ternary molten salt crystals are explored and the catalytic pyrolysis mechanism of Datong coal is investigated. The reaction mechanisms of coal are achieved by thermal gravimetric analyzer (TGA), and a reactive kinetic model is constructed. The microcosmic structure and macerals are observed by scanning electron microscope (SEM). The catalytic effects of ternary molten salt crystals at different stages of pyrolysis are analyzed. The experimental results show that Ni-Co ternary molten salt catalysts have the capability to bring down activation energy required by pyrolytic reactions at its initial phase. Also, the catalysts exert a preferable catalytic action on macromolecular structure decomposition and free radical polycondensation reactions. Furthermore, the high-temperature condensation polymerization is driven to decompose further with a faster reaction rate by the additions of Ni-Co ternary molten salt crystal catalysts. According to pyrolysis kinetic research, the addition of catalysts can effectively decrease the activation energy needed in each phase of pyrolysis reaction.

Preparation of Al-La Master Alloy by Thermite Reaction in NaF-NaCl-KCl Molten Salt

NASA Astrophysics Data System (ADS)

Jang, Poknam; Li, Hyonmo; Kim, Wenjae; Wang, Zhaowen; Liu, Fengguo

2015-05-01

A NaF-NaCl-KCl ternary system containing La2O3 was investigated for the preparation of Al-La master alloy by the thermite reaction method. The solubility of La2O3 in NaF-NaCl-KCl molten salt was determined by the method of isothermal solution saturation. Inductively coupled plasma-optical emission spectroscopy and x-ray diffraction (XRD) analyses were used to consider the content of La2O3 in molten salt and the supernatant composition of molten salt after dissolution of La2O3, respectively. The results showed that the content of NaF had a positive influence on the solubility of La2O3 in NaF-NaCl-KCl molten salts, and the solubility of La2O3 could reach 8.71 wt.% in molten salts of 50 wt.%NaF-50 wt.% (44 wt.%NaCl + 56 wt.%KCl). The XRD pattern of cooling molten salt indicated the formation of LaOF in molten salt, which was probably obtained by the reaction between NaF and La2O3. The kinetic study showed that the thermite reaction was in accord with a first-order reaction model. The main influence factors on La content in the Al-La master alloy product, including molten salt composition, amount of Al, concentration of La2O3, stirring, reduction time and temperature, were investigated by single-factor experimentation. The content of La in the Al-La master alloy could be reached to 10.1 wt.%.

Analysis of fluid fuel flow to the neutron kinetics on molten salt reactor FUJI-12

NASA Astrophysics Data System (ADS)

Aji, Indarta Kuncoro; Waris, Abdul; Permana, Sidik

2015-09-01

Molten Salt Reactor is a reactor are operating with molten salt fuel flowing. This condition interpret that the neutron kinetics of this reactor is affected by the flow rate of the fuel. This research analyze effect by the alteration velocity of the fuel by MSR type Fuji-12, with fuel composition LiF-BeF2-ThF4-233UF4 respectively 71.78%-16%-11.86%-0.36%. Calculation process in this study is performed numerically by SOR and finite difference method use C programming language. Data of reactivity, neutron flux, and the macroscopic fission cross section for calculation process obtain from SRAC-CITATION (Standard thermal Reactor Analysis Code) and JENDL-4.0 data library. SRAC system designed and developed by JAEA (Japan Atomic Energy Agency). This study aims to observe the effect of the velocity of fuel salt to the power generated from neutron precursors at fourth year of reactor operate (last critical condition) with number of multiplication effective; 1.0155.

Trapping of Li(+) Ions by [ThFn](4-n) Clusters Leading to Oscillating Maxwell-Stefan Diffusivity in the Molten Salt LiF-ThF4.

PubMed

Chakraborty, Brahmananda; Kidwai, Sharif; Ramaniah, Lavanya M

2016-08-18

A molten salt mixture of lithium fluoride and thorium fluoride (LiF-ThF4) serves as a fuel as well as a coolant in the most sophisticated molten salt reactor (MSR). Here, we report for the first time dynamic correlations, Onsager coefficients, Maxwell-Stefan (MS) diffusivities, and the concentration dependence of density and enthalpy of the molten salt mixture LiF-ThF4 at 1200 K in the composition range of 2-45% ThF4 and also at eutectic composition in the temperature range of 1123-1600 K using Green-Kubo formalism and equilibrium molecular dynamics simulations. We have observed an interesting oscillating pattern for the MS diffusivity for the cation-cation pair, in which ĐLi-Th oscillates between positive and negative values with the amplitude of the oscillation reducing as the system becomes rich in ThF4. Through the velocity autocorrelation function, vibrational density of states, radial distribution function analysis, and structural snapshots, we establish an interplay between the local structure and multicomponent dynamics and predict that formation of negatively charged [ThFn](4-n) clusters at a higher ThF4 mole % makes positively charged Li(+) ions oscillate between different clusters, with their range of motion reducing as the number of [ThFn](4-n) clusters increases, and finally Li(+) ions almost get trapped at a higher ThF4% when the electrostatic force on Li(+) exerted by various surrounding clusters gets balanced. Although reports on variations of density and enthalpy with temperature exist in the literature, for the first time we report variations of the density and enthalpy of LiF-ThF4 with the concentration of ThF4 (mole %) and fit them with the square root function of ThF4 concentration, which will be very useful for experimentalists to obtain data over a range of concentrations from fitting the formula for design purposes. The formation of [ThFn](4-n) clusters and the reduction in the diffusivity of the ions at a higher ThF4% may limit the

Grain orientation in high Tc superconductors by molten salt powder synthesis

NASA Technical Reports Server (NTRS)

Gopalakrishnan, Sudhakar; Schulze, Walter A.

1991-01-01

The molten salt or the flux method is used to fabricate a grain oriented YBa2Cu3O(7-x) (123) superconductor. Here we suggest a two-stage approach in using the 'green phase', Y2BaCuO5 (211), as seed crystals in the formation of YBa2Cu3O(7-x). The process uses Y2BaCuO5 formed by molten salt synthesis. The Y2BaCuO5 phase was observed to be stable in water and in most of the salt systems. Salt processing can form a small quantity of anisotropic particles of Y2BaCuO5. This material can form the 123 phase when tape cast and sintered in the presence of the required levels of Ba and Cu.

The elemental move characteristic of nickel-based alloy in molten salt corrosion by using nuclear microprobe

NASA Astrophysics Data System (ADS)

Lei, Qiantao; Liu, Ke; Gao, Jie; Li, Xiaolin; Shen, Hao; Li, Yan

2017-08-01

Nickel-based alloys as candidate materials for Thorium Molten Salt Reactor (TMSR), need to be used under high temperature in molten salt environment. In order to ensure the safety of the reactor running, it is necessary to study the elemental move characteristic of nickel-based alloys in the high temperature molten salts. In this work, the scanning nuclear microprobe at Fudan University was applied to study the elemental move. The Nickel-based alloy samples were corroded by molten salt at different temperatures. The element concentrations in the Nickel-based alloys samples were determined by the scanning nuclear microprobe. Micro-PIXE results showed that the element concentrations changed from the interior to the exterior of the alloy samples after the corrosion.

Effects of SO42- ions on the corrosion of GH3535 weld joint in FLiNaK molten salt

NASA Astrophysics Data System (ADS)

Zhu, Yasheng; Qiu, Jie; Hou, Juan; Liu, Wenguan; Chen, Huaican; Ai, Hua; Yu, Guojun; Wang, Jianqiang; Zhou, Xingtai

2017-08-01

The present work studied the impact of SO42- ions on the corrosion behaviors of GH3535 weld joint in FLiNaK molten salt. The concentration of SO42- ions in the FLiNaK molten salt was controlled by adjusting the quantity of Na2SO4 added into the salt. Results indicate that the SO42- ions in the FLiNaK salt speed up the corrosion rate remarkably by promoting the dissolution of Cr from the alloy matrix into the salt. With the concentration of SO42- ions in the FLiNaK salt increases from 100 ppm to 1000 ppm, the weight losses and the Cr depletion layer depths of the corroded specimens increase linearly. Even in the case of the heavy corrosion attack caused by the SO42- ions, the corrosion performance is similar between the base zone and fusion zone in the GH3535 weld joint. It is demonstrated that the structural diversity caused by the welding process has little impact on the corrosion performances of GH3535 alloy in FLiNaK molten salt.

Molten Salt Promoting Effect in Double Salt CO2 Absorbents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Keling; Li, Xiaohong S.; Chen, Haobo

2016-01-01

The purpose of this paper is to elaborate on the concept of molten salts as catalysts for CO2 absorption by MgO, and extend these observations to the MgO-containing double salt oxides. We will show that the phenomena involved with CO2 absorption by MgO and MgO-based double salts are similar and general, but with some important differences. This paper focuses on the following key concepts: i) identification of conditions that favor or disfavor participation of isolated MgO during double salt absorption, and investigation of methods to increase the absorption capacity of double salt systems by including MgO participation; ii) examination ofmore » the relationship between CO2 uptake and melting point of the promoter salt, leading to the recognition of the role of pre-melting (surface melting) in these systems; and iii) extension of the reaction pathway model developed for the MgO-NaNO3 system to the double salt systems. This information advances our understanding of MgO-based CO2 absorption systems for application with pre-combustion gas streams.« less

Investigation on corrosion behavior of Ni-based alloys in molten fluoride salt using synchrotron radiation techniques

NASA Astrophysics Data System (ADS)

Liu, Min; Zheng, Junyi; Lu, Yanling; Li, Zhijun; Zou, Yang; Yu, Xiaohan; Zhou, Xingtai

2013-09-01

Ni-based alloys have been selected as the structural materials in molten-salt reactors due to their high corrosion resistance and excellent mechanical properties. In this paper, the corrosion behavior of some Ni-based superalloys including Inconel 600, Hastelloy X and Hastelloy C-276 were investigated in molten fluoride salts at 750 °C. Morphology and microstructure of corroded samples were analyzed using scanning electron microscope (SEM), synchrotron radiation X-ray microbeam fluorescence (μ-XRF) and synchrotron radiation X-ray diffraction (SR-XRD) techniques. Results from μ-XRF and SR-XRD show that the main depleted alloying element of Ni-based alloys in molten fluoride salt is Cr. In addition, the results indicate that Mo can enhance the corrosion resistance in molten FLiNaK salts. Among the above three Ni-based alloys, Hastelloy C-276 exhibits the best corrosion resistance in molten fluoride salts 750 °C. Higher-content Mo and lower-content Cr in Hastelloy C-276 alloy were responsible for the better anti-corrosive performance, compared to the other two alloys.

Effect of Using Thorium Molten Salts on the Neutronic Performance of PACER

NASA Astrophysics Data System (ADS)

Acır, Adem; Übeyli, Mustafa

2010-04-01

Utilization of nuclear explosives can produce a significant amount of energy which can be converted into electricity via a nuclear fusion power plant. An important fusion reactor concept using peaceful nuclear explosives is called as PACER which has an underground containment vessel to handle the nuclear explosives safely. In this reactor, Flibe has been considered as a working coolant for both tritium breeding and heat transferring. However, the rich neutron source supplied from the peaceful nuclear explosives can be used also for fissile fuel production. In this study, the effect of using thorium molten salts on the neutronic performance of the PACER was investigated. The computations were performed for various coolants bearing thorium and/or uranium-233 with respect to the molten salt zone thickness in the blanket. Results pointed out that an increase in the fissile content of the salt increased the neutronic performance of the reactor remarkably. In addition, higher energy production was obtained with thorium molten salts compared to the pure mode of the reactor. Moreover, a large quantity of 233U was produced in the blanket in all cases.

Molten salt lithium cells

DOEpatents

Raistrick, I.D.; Poris, J.; Huggins, R.A.

1980-07-18

Lithium-based cells are promising for applications such as electric vehicles and load-leveling for power plants since lithium is very electropositive and light weight. One type of lithium-based cell utilizes a molten salt electrolyte and is operated in the temperature range of about 400 to 500/sup 0/C. Such high temperature operation accelerates corrosion problems and a substantial amount of energy is lost through heat transfer. The present invention provides an electrochemical cell which may be operated at temperatures between about 100 to 170/sup 0/C. The cell is comprised of an electrolyte, which preferably includes lithium nitrate, and a lithium or lithium alloy electrode.

Molten salt lithium cells

DOEpatents

Raistrick, Ian D.; Poris, Jaime; Huggins, Robert A.

1983-01-01

Lithium-based cells are promising for applications such as electric vehicles and load-leveling for power plants since lithium is very electropositive and light weight. One type of lithium-based cell utilizes a molten salt electrolyte and is operated in the temperature range of about 400.degree.-500.degree. C. Such high temperature operation accelerates corrosion problems and a substantial amount of energy is lost through heat transfer. The present invention provides an electrochemical cell (10) which may be operated at temperatures between about 100.degree.-170.degree. C. Cell (10) comprises an electrolyte (16), which preferably includes lithium nitrate, and a lithium or lithium alloy electrode (12).

Molten salt lithium cells

DOEpatents

Raistrick, Ian D.; Poris, Jaime; Huggins, Robert A.

1982-02-09

Lithium-based cells are promising for applications such as electric vehicles and load-leveling for power plants since lithium is very electropositive and light weight. One type of lithium-based cell utilizes a molten salt electrolyte and is operated in the temperature range of about 400.degree.-500.degree. C. Such high temperature operation accelerates corrosion problems and a substantial amount of energy is lost through heat transfer. The present invention provides an electrochemical cell (10) which may be operated at temperatures between about 100.degree.-170.degree. C. Cell (10) comprises an electrolyte (16), which preferably includes lithium nitrate, and a lithium or lithium alloy electrode (12).

Molten Chloride Salts for Heat Transfer in Nuclear Systems

NASA Astrophysics Data System (ADS)

Ambrosek, James Wallace

2011-12-01

A forced convection loop was designed and constructed to examine the thermal-hydraulic performance of molten KCl-MgCl2 (68-32 at %) salt for use in nuclear co-generation facilities. As part of this research, methods for prediction of the thermo-physical properties of salt mixtures for selection of the coolant salt were studied. In addition, corrosion studies of 10 different alloys were exposed to the KCl-MgCl2 to determine a suitable construction material for the loop. Using experimental data found in literature for unary and binary salt systems, models were found, or developed to extrapolate the available experimental data to unstudied salt systems. These property models were then used to investigate the thermo-physical properties of the LINO3-NaNO3-KNO 3-Ca(NO3), system used in solar energy applications. Using these models, the density, viscosity, adiabatic compressibility, thermal conductivity, heat capacity, and melting temperatures of higher order systems can be approximated. These models may be applied to other molten salt systems. Coupons of 10 different alloys were exposed to the chloride salt for 100 hours at 850°C was undertaken to help determine with which alloy to construct the loop. Of the alloys exposed, Haynes 230 had the least amount of weight loss per area. Nickel and Hastelloy N performed best based on maximum depth of attack. Inconel 625 and 718 had a nearly uniform depletion of Cr from the surface of the sample. All other alloys tested had depletion of Cr along the grain boundaries. The Nb in Inconel 625 and 718 changed the way the Cr is depleted in these alloys. Grain-boundary engineering (GBE) of Incoloy 800H improved the corrosion resistance (weight loss and maximum depth of attack) by nearly 50% as compared to the as-received Incoloy 800H sample. A high temperature pump, thermal flow meter, and pressure differential device was designed, constructed and tested for use in the loop, The heat transfer of the molten chloride salt was found to

Electrochemical Synthesis of Magnesium Hexaboride by Molten Salt Technique

PubMed Central

Angappan, S.; Kalaiselvi, N.; Sudha, R.; Visuvasam, A.

2014-01-01

The present work reports electrochemical synthesis of MgB6 from molten salts using the precursor consists of LiF–B2O3–MgCl2. An attempt has been made to synthesize metastable phase MgB6 crystal by electrolysis method. DTA/TGA studies were made to determine the eutectic point of the melt and it was found to be around 900°C. The electrolysis was performed at 900°C under argon atmosphere, at current density of 1.5 A/cm2. The electrodeposited crystals were examined using XRD, SEM, and XPS. From the above studies, the electrochemical synthesis method for hypothetical MgB6 from chloro-oxy-fluoride molten salt system is provided. Mechanism for the formation of magnesium hexaboride is discussed. PMID:27350961

Electrochemical Synthesis of Magnesium Hexaboride by Molten Salt Technique.

PubMed

Angappan, S; Kalaiselvi, N; Sudha, R; Visuvasam, A

2014-01-01

The present work reports electrochemical synthesis of MgB6 from molten salts using the precursor consists of LiF-B2O3-MgCl2. An attempt has been made to synthesize metastable phase MgB6 crystal by electrolysis method. DTA/TGA studies were made to determine the eutectic point of the melt and it was found to be around 900°C. The electrolysis was performed at 900°C under argon atmosphere, at current density of 1.5 A/cm(2). The electrodeposited crystals were examined using XRD, SEM, and XPS. From the above studies, the electrochemical synthesis method for hypothetical MgB6 from chloro-oxy-fluoride molten salt system is provided. Mechanism for the formation of magnesium hexaboride is discussed.

Molten nitrate salt technology development

NASA Astrophysics Data System (ADS)

Carling, R. W.

1981-04-01

This paper presents an overview of the experimental programs underway in support of the Thermal Energy Storage for Solar Thermal Applications (TESSTA) program. The experimental programs are concentrating on molten nitrate salts which have been proposed as heat transfer and energy storage medium. The salt composition of greatest interest is drawsalt, nominally a 50-50 molar mixture of NaNO3 and KNO3 with a melting point of 220 C. Several technical uncertainties have been identified that must be resolved before nitrate based solar plants can be commercialized. Research programs at Sandia National Laboratories, universities, and industrial suppliers have been implemented to resolve these technical uncertainties. The experimental programs involve corrosion, decomposition, physical properties, and environmental cracking. Summaries of each project and how they impact central receiver applications such as the repowering/industrial retrofit and cogeneration program are presented.

Redox condition in molten salts and solute behavior: A first-principles molecular dynamics study

NASA Astrophysics Data System (ADS)

Nam, Hyo On; Morgan, Dane

2015-10-01

Molten salts technology is of significant interest for nuclear, solar, and other energy systems. In this work, first-principles molecular dynamics (FPMD) was used to model the solute behavior in eutectic LiCl-KCl and FLiBe (Li2BeF4) melts at 773 K and 973 K, respectively. The thermo-kinetic properties for solute systems such as the redox potential, solute diffusion coefficients and structural information surrounding the solute were predicted from FPMD modeling and the calculated properties are generally in agreement with the experiments. In particular, we formulate an approach to model redox energetics vs. chlorine (or fluorine) potential from first-principles approaches. This study develops approaches for, and demonstrates the capabilities of, FPMD to model solute properties in molten salts.

Analysis of fluid fuel flow to the neutron kinetics on molten salt reactor FUJI-12

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aji, Indarta Kuncoro, E-mail: indartaaji@s.itb.ac.id; Waris, Abdul, E-mail: awaris@fi.itb.ac.id; Permana, Sidik

Molten Salt Reactor is a reactor are operating with molten salt fuel flowing. This condition interpret that the neutron kinetics of this reactor is affected by the flow rate of the fuel. This research analyze effect by the alteration velocity of the fuel by MSR type Fuji-12, with fuel composition LiF-BeF{sub 2}-ThF{sub 4}-{sup 233}UF{sub 4} respectively 71.78%-16%-11.86%-0.36%. Calculation process in this study is performed numerically by SOR and finite difference method use C programming language. Data of reactivity, neutron flux, and the macroscopic fission cross section for calculation process obtain from SRAC-CITATION (Standard thermal Reactor Analysis Code) and JENDL-4.0 datamore » library. SRAC system designed and developed by JAEA (Japan Atomic Energy Agency). This study aims to observe the effect of the velocity of fuel salt to the power generated from neutron precursors at fourth year of reactor operate (last critical condition) with number of multiplication effective; 1.0155.« less

Electrochemical Deposition of High Purity Silicon from Molten Salts

NASA Astrophysics Data System (ADS)

Haarberg, Geir Martin

Several approaches were tried in order to develop an electrochemical route for producing high purity silicon from molten salts. SiO2, K2SiF6 and metallurgical silicon were used as the source of silicon. Molten electrolytes based on chloride (CaCl2-NaCl) and fluoride (LiF-KF) at temperatures from 550 - 900 oC were used. Transient electrochemical techniques were used to study the electrochemical behaviour of dissolved silicon species. Electrolysis experiments were carried out to deposit silicon.

Electrochemical Deposition of High Purity Silicon in Molten Salts

NASA Astrophysics Data System (ADS)

Haarberg, Geir Martin

Several approaches were tried in order to develop an electrochemical route for producing high purity silicon from molten salts. SiO2, K2SiF6 and metallurgical silicon were used as the source of silicon. Molten electrolytes based on chloride (CaCl2-NaCl) and fluoride (LiF-KF) at temperatures from 550 - 900 °C were used. Transient electrochemical techniques were used to study the electrochemical behaviour of dissolved silicon species. Electrolysis experiments were carried out to deposit silicon.

Temperature effect on laser-induced breakdown spectroscopy spectra of molten and solid salts

NASA Astrophysics Data System (ADS)

Hanson, Cynthia; Phongikaroon, Supathorn; Scott, Jill R.

2014-07-01

Laser-induced breakdown spectroscopy (LIBS) has been investigated as a potential analytical tool to improve operations and safeguards for electrorefiners, such as those used in processing spent nuclear fuel. This study set out to better understand the effect of sample temperature and physical state on LIBS spectra of molten and solid salts by building calibration curves of cerium and assessing self-absorption, plasma temperature, electron density, and local thermal equilibrium (LTE). Samples were composed of a LiCl-KCl eutectic salt, an internal standard of MnCl2, and varying concentrations of CeCl3 (0.1, 0.3, 0.5, 0.8, and 1.0 wt.% Ce) under different temperatures (773, 723, 673, 623, and 573 K). Analysis of salts in their molten form is preferred as plasma plumes from molten samples experienced less self-absorption, less variability in plasma temperature, and higher clearance of the minimum electron density required for local thermal equilibrium. These differences are attributed to plasma dynamics as a result of phase changes. Spectral reproducibility was also better in the molten state due to sample homogeneity.

Preparation of nanocrystalline silicon from SiCl4 at 200 °C in molten salt for high-performance anodes for lithium ion batteries.

PubMed

Lin, Ning; Han, Ying; Wang, Liangbiao; Zhou, Jianbin; Zhou, Jie; Zhu, Yongchun; Qian, Yitai

2015-03-16

Crystalline Si nanoparticles are prepared by reduction of SiCl4 with metallic magnesium in the molten salt of AlCl3 at 200 °C in an autoclave. AlCl3 not only acts as molten salt, but also participates in the reaction. The related experiments confirm that metallic Mg reduces AlCl3 to create nascent Al which could immediately reduce SiCl4 to Si, and the by-product MgCl2 would combine with AlCl3 forming complex of MgAl2Cl8. As anode for rechargeable lithium ion batteries, the as-prepared Si delivers the reversible capacity of 3083 mAh g(-1) at 1.2 A g(-1) after 50 cycles, and 1180 mAh g(-1) at 3 A g(-1) over 500 cycles. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reductive smelting of spent lead-acid battery colloid sludge in a molten Na2CO3 salt

NASA Astrophysics Data System (ADS)

Hu, Yu-jie; Tang, Chao-bo; Tang, Mo-tang; Chen, Yong-ming

2015-08-01

Lead extraction from spent lead-acid battery paste in a molten Na2CO3 salt containing ZnO as a sulfur-fixing agent was studied. Some influencing factors, including smelting temperature, reaction time, ZnO and salt dosages, were investigated in detail using single-factor experiments. The optimum conditions were determined as follows: T = 880°C; t = 60 min; Na2CO3/paste mass ratio = 2.8:1; and the ZnO dosage is equal to the stoichiometric requirement. Under the optimum conditions, the direct recovery rate of lead reached 98.14%. The results suggested that increases in temperature and salt dosage improved the direct recovery rate of lead. XRD results and thermodynamic calculations indicated that the reaction approaches of lead and sulfur were PbSO4→Pb and PbSO4→ZnS, respectively. Sulfur was fixed in the form of ZnS, whereas the molten salt did not react with other components, serving only as a reaction medium.

Investigation on the Oxidation and Reduction of Titanium in Molten Salt with the Soluble TiC Anode

NASA Astrophysics Data System (ADS)

Wang, Shulan; Wan, Chaopin; Liu, Xuan; Li, Li

2015-12-01

To reveal the oxidation process of titanium from TiC anode and the reduction mechanism of titanium ions in molten NaCl-KCl, the polarization curve of TiC anode in molten NaCl-KCl and cyclic voltammograms of the molten salt after polarization were studied. Investigation on the polarization curve shows that titanium can be oxidized and dissociated from the TiC anode at very low potential. The cyclic voltammograms demonstrated that the reduction reaction of titanium ions in the molten salt is a one-step process. By potentiostatic electrolysis, dendritic titanium is obtained on the steel plate. The work promotes the understanding on the process of electrochemical oxidization/dissociation of titanium from TiC anode and the reduction mechanism of titanium ions in molten salt.

Molten salt power towers operating at 600–650 °C: Salt selection and cost benefits

DOE PAGES

Turchi, Craig S.; Vidal, Judith; Bauer, Matthew

2018-03-14

This analysis examines the potential benefit of adopting the supercritical carbon dioxide (sCO 2) Brayton cycle at 600-650 degrees C compared to the current state-of-the-art power tower operating a steam-Rankine cycle with solar salt at approximately 574 degrees C. The analysis compares a molten-salt power tower configuration using direct storage of solar salt (60:40 wt% sodium nitrate: potassium nitrate) or single-component nitrate salts at 600 degrees C or alternative carbonate- or chloride-based salts at 650 degrees C.

Molten salt power towers operating at 600–650 °C: Salt selection and cost benefits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turchi, Craig S.; Vidal, Judith; Bauer, Matthew

This analysis examines the potential benefit of adopting the supercritical carbon dioxide (sCO 2) Brayton cycle at 600-650 degrees C compared to the current state-of-the-art power tower operating a steam-Rankine cycle with solar salt at approximately 574 degrees C. The analysis compares a molten-salt power tower configuration using direct storage of solar salt (60:40 wt% sodium nitrate: potassium nitrate) or single-component nitrate salts at 600 degrees C or alternative carbonate- or chloride-based salts at 650 degrees C.

Deployment of quasi-digital sensor for high temperature molten salt level measurement in pyroprocessing plants.

PubMed

Sanga, Ramesh; Agarwal, Sourabh; Sivaramakrishna, M; Rao, G Prabhakara

2018-04-01

Development of a liquid molten salt level sensor device that can detect the level of liquid molten salt in the process vessels of pyrochemical reprocessing of spent metallic fuels is detailed. It is proposed to apply a resistive-type pulsating sensor-based level measurement approach. There are no commercially available sensors due to limitations of high temperature, radiation, and physical dimensions. A compact, simple, rugged, low power, and high precise pulsating sensor-based level probe and simple instrumentation for the molten salt liquid level sensor to work in the extreme conditions has been indigenously developed, with high precision and accuracy. The working principle, design concept, and results have been discussed. This level probe is mainly composed of the variable resistor made up of ceramic rods. This resistor constitutes the part of resistance-capacitance-type Logic Gate Oscillator (LGO). A change in the molten salt level inside the tank causes a small change in the resistance which in turn changes the pulse frequency of the LGO. Thus the frequency, the output of the instrument that is displayed on the LCD of an embedded system, is a function of molten salt level. In the present design, the range of level measurement is about 10 mm. The sensitivity in position measurement up to 10 mm is ∼2.5 kHz/mm.

Deployment of quasi-digital sensor for high temperature molten salt level measurement in pyroprocessing plants

NASA Astrophysics Data System (ADS)

Sanga, Ramesh; Agarwal, Sourabh; Sivaramakrishna, M.; Rao, G. Prabhakara

2018-04-01

Development of a liquid molten salt level sensor device that can detect the level of liquid molten salt in the process vessels of pyrochemical reprocessing of spent metallic fuels is detailed. It is proposed to apply a resistive-type pulsating sensor-based level measurement approach. There are no commercially available sensors due to limitations of high temperature, radiation, and physical dimensions. A compact, simple, rugged, low power, and high precise pulsating sensor-based level probe and simple instrumentation for the molten salt liquid level sensor to work in the extreme conditions has been indigenously developed, with high precision and accuracy. The working principle, design concept, and results have been discussed. This level probe is mainly composed of the variable resistor made up of ceramic rods. This resistor constitutes the part of resistance-capacitance-type Logic Gate Oscillator (LGO). A change in the molten salt level inside the tank causes a small change in the resistance which in turn changes the pulse frequency of the LGO. Thus the frequency, the output of the instrument that is displayed on the LCD of an embedded system, is a function of molten salt level. In the present design, the range of level measurement is about 10 mm. The sensitivity in position measurement up to 10 mm is ˜2.5 kHz/mm.

Thorium and Molten Salt Reactors: "Essential Questions for Classroom Discussions"

ERIC Educational Resources Information Center

DiLisi, Gregory A.; Hirsch, Allison; Murray, Meredith; Rarick, Richard

2018-01-01

A little-known type of nuclear reactor called the "molten salt reactor" (MSR), in which nuclear fuel is dissolved in a liquid carrier salt, was proposed in the 1940s and developed at the Oak Ridge National Laboratory in the 1960s. Recently, the MSR has generated renewed interest as a remedy for the drawbacks associated with conventional…

Molten salt extraction of transuranic and reactive fission products from used uranium oxide fuel

DOEpatents

Herrmann, Steven Douglas

2014-05-27

Used uranium oxide fuel is detoxified by extracting transuranic and reactive fission products into molten salt. By contacting declad and crushed used uranium oxide fuel with a molten halide salt containing a minor fraction of the respective uranium trihalide, transuranic and reactive fission products partition from the fuel to the molten salt phase, while uranium oxide and non-reactive, or noble metal, fission products remain in an insoluble solid phase. The salt is then separated from the fuel via draining and distillation. By this method, the bulk of the decay heat, fission poisoning capacity, and radiotoxicity are removed from the used fuel. The remaining radioactivity from the noble metal fission products in the detoxified fuel is primarily limited to soft beta emitters. The extracted transuranic and reactive fission products are amenable to existing technologies for group uranium/transuranic product recovery and fission product immobilization in engineered waste forms.

Beryllium Interactions in Molten Salts

DOE Office of Scientific and Technical Information (OSTI.GOV)

G. S. Smolik; M. F. Simpson; P. J. Pinhero

Molten flibe (2LiF·BeF2) is a candidate as a cooling and tritium breeding media for future fusion power plants. Neutron interactions with the salt will produce tritium and release excess free fluorine ions. Beryllium metal has been demonstrated as an effective redox control agent to prevent free fluorine, or HF species, from reacting with structural metal components. The extent and rate of beryllium solubility in a pot design experiments to suppress continuously supplied hydrogen fluoride gas has been measured and modeled[ ]. This paper presents evidence of beryllium loss from specimens, a dependence of the loss upon bi-metal coupling, i.e., galvanicmore » effect, and the partitioning of the beryllium to the salt and container materials. Various posttest investigative methods, viz., scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) were used to explore this behavior.« less

Pyridinium molten salts as co-adsorbents in dye-sensitized solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Jui-Cheng; Sun, I-Wen; Yang, Cheng-Hsien

2011-01-15

The influence of using pyridinium molten salts as co-adsorbents to modify the monolayer of a TiO{sub 2} semiconductor on the performance of a dye-sensitized solar cell is studied. The current-voltage characteristics are measured under AM 1.5 (100 mW cm{sup -2}). The pyridinium molten salts significantly enhance the open-circuit photovoltage (V{sub oc}), the short circuit photocurrent density (J{sub sc}) as well as the solar energy conversion efficiency ({eta}). 1-Ethyl-3-carboxypyridinium iodide ([ECP][I]) is applied successfully to prepare an insulating molecular layer with N719, and achieve high energy conversion efficiency as high as 4.49% at 100 mW cm{sup -2} and AM 1.5. Themore » resulting efficiency is 20% higher than that of a non-additive device. This enhancement of conversion efficiency is attributed to the negative shift of the conduction band (CB) edge and the abundant concentration of I{sup -} on the surface of the electrode when using [ECP][I] as the co-adsorbent. (author)« less

Transient analysis of a molten salt central receiver (MSCR) in a solar power plant

NASA Astrophysics Data System (ADS)

Joshi, A.; Wang, C.; Akinjiola, O.; Lou, X.; Neuschaefer, C.; Quinn, J.

2016-05-01

Alstom is developing solar power tower plants utilizing molten salt as the working fluid. In solar power tower, the molten salt central receiver (MSCR) atop of the tower is constructed of banks of tubes arranged in panels creating a heat transfer surface exposed to the solar irradiation from the heliostat field. The molten salt heat transfer fluid (HTF), in this case 60/40%wt NaNO3-KNO3, flows in serpentine flow through the surface collecting sensible heat thus raising the HTF temperature from 290°C to 565°C. The hot molten salt is stored and dispatched to produce superheated steam in a steam generator, which in turn produces electricity in the steam turbine generator. The MSCR based power plant with a thermal energy storage system (TESS) is a fully dispatchable renewable power plant with a number of opportunities for operational and economic optimization. This paper presents operation and controls challenges to the MSCR and the overall power plant, and the use of dynamic model computer simulation based transient analyses applied to molten salt based solar thermal power plant. This study presents the evaluation of the current MSCR design, using a dynamic model, with emphasis on severe events affecting critical process response, such as MS temperature deviations, and recommend MSCR control design improvements based on the results. Cloud events are the scope of the transient analysis presented in this paper. The paper presents results from a comparative study to examine impacts or effects on key process variables related to controls and operation of the MSCR plant.

Electrochemical synthesis of superconductive MgB 2 from molten salts

NASA Astrophysics Data System (ADS)

Yoshii, Kenji; Abe, Hideki

2003-05-01

We have found that superconductive MgB2 can be electrochemically synthesized from molten salts. The electrolysis was performed in an Ar flow at 600 °C on fused mixtures composed of MgCl2, MgB2O4, Na2B2O4 and alkali halides such as KCl, NaCl, and LiCl. Superconductivity was observed for a wide variety of electrolytes. It was also found that the magnetic and electrical transport properties are the most improved for samples prepared from MgCl2-NaCl-KCl-MgB2O4 electrolytes.

Thermal Storage Properties of Molten Nitrate Salt-Based Nanofluids with Graphene Nanoplatelets.

PubMed

Xie, Qiangzhi; Zhu, Qunzhi; Li, Yan

2016-12-01

In this study, the effect of concentration of nanoparticles on the thermal storage properties of molten nitrate salt-based nanofluids with graphene nanoplatelets (GNPs) was investigated. Solar salt consisting of sodium nitrate and potassium nitrate was utilized as the base material for the nanofluids. Homogeneous dispersion of GNPs within the solar salt was observed through scanning electron microscopy analysis. For both solar salt and resultant nanofluids, differential scanning calorimetry was employed to measure the thermal storage properties, including characteristic temperatures of phase change, startup heat, and specific heat capacity (SHC). A maximum increase of 16.7 % in SHC at the liquid phase was found at an optimal concentration of 1 wt% of GNPs. At the same concentration, the onset temperature decreased by 10.4 °C, the endset temperature decreased by 4.7 °C, and the startup heat decreased by 9 %.

Molten salt battery having inorganic paper separator

DOEpatents

Walker, Jr., Robert D.

1977-01-01

A high temperature secondary battery comprises an anode containing lithium, a cathode containing a chalcogen or chalcogenide, a molten salt electrolyte containing lithium ions, and a separator comprising a porous sheet comprising a homogenous mixture of 2-20 wt.% chrysotile asbestos fibers and the remainder inorganic material non-reactive with the battery components. The non-reactive material is present as fibers, powder, or a fiber-powder mixture.

Molten Salts and Isotope Separation

NASA Astrophysics Data System (ADS)

Lantelme, Frédéric

2013-02-01

The work on molten salts and isotope separation performed over the years at Université Pierre et Marie Curie and at Collège de France is critically reviewed. This research, closely related to A. Klemm's pioneering contributions, leads among other things to the discovery of the effect now called the `Chemla effect', after the late Professor Marius Chemla. These studies of ionic motions in melts, and liquids in general, have greatly benefitted from recent advances in molecular simulations. Some recent results of such simulations - molecular dynamics (MD) and Brownian dynamics (BD) - as well as of related theoretical work are discussed.

Original Synthetic Route To Obtain a SrAl2O4 Phosphor by the Molten Salt Method: Insights into the Reaction Mechanism and Enhancement of the Persistent Luminescence.

PubMed

Rojas-Hernandez, Rocío Estefanía; Rubio-Marcos, Fernando; Gonçalves, Ricardo Henrique; Rodriguez, Miguel Ángel; Véron, Emmanuel; Allix, Mathieu; Bessada, Catherine; Fernandez, José Francisco

2015-10-19

SrAl2O4:Eu(2+), Dy(3+) has been extensively studied for industrial applications in the luminescent materials field, because of its excellent persistent luminescence properties and chemical stability. Traditionally, this strontium aluminate material is synthesized in bulk form and/or fine powder by the classic solid-state method. Here, we report an original synthetic route, a molten salt assisted process, to obtain highly crystalline SrAl2O4 powder with nanometer-scale crystals. The main advantages of salt addition are the increase of the reaction rate and the significant reduction of the synthesis temperature because of much higher mobility of reactants in the liquid medium than in the solid-state method. In particular, the formation mechanism of SrAl2O4, the role of the salt, and the phase's evolution have been explored as a function of temperature and time. Phosphorescent powders based on SrAl2O4:Eu(2+), Dy(3+) with high crystallinity are obtained after 1 h treatment at 900 °C. This work could promote further interest in adopting the molten salt strategy to process high-crystallinity materials with enhanced luminescence to design technologically relevant phosphors.

Low temperature synthesis & characterization of lead-free BCZT ceramics using molten salt method

NASA Astrophysics Data System (ADS)

Jai Shree, K.; Chandrakala, E.; Das, Dibakar

2018-04-01

Piezoelectric properties are greatly influenced by the synthesis route, microstructure, stoichiometry of the chemical composition, purity of the starting materials. In this study, molten salt method was used to prepare lead-free BCZT ceramics. Molten salt method is one of the simplestmethods to prepare chemically-purified, single phase powders in high yield often at lower temperatures and shorten reaction time. Calcination of the molten salt synthesized powders resulted in asingle-phase perovskite structure at 1000 °C which is ˜ 350 °C less than the conventional solid-sate reaction method. With increasing calcination temperature the average template size was increased (˜ 0.5-2 µm). Formation of well dispersive templates improves the sinterability at lower temperatures. Lead-free BCZT ceramics sintered at 1500 °C for 2 h resulted in homogenous and highly dense microstructure with ˜92% of the theoretical density and a grain size of ˜ 35 µm. This highly dense microstructure could enhance the piezoelectric properties of the system.

Molten-Salt-Based Growth of Group III Nitrides

DOEpatents

Waldrip, Karen E.; Tsao, Jeffrey Y.; Kerley, Thomas M.

2008-10-14

A method for growing Group III nitride materials using a molten halide salt as a solvent to solubilize the Group-III ions and nitride ions that react to form the Group III nitride material. The concentration of at least one of the nitride ion or Group III cation is determined by electrochemical generation of the ions.

Proposed Guidance for Preparing and Reviewing Molten Salt Nonpower Reactor Licence Applications (NUREG-1537)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belles, Randy; Flanagan, George F.; Voth, Marcus

Development of non-power molten salt reactor (MSR) test facilities is under consideration to support the analyses needed for development of a full-scale MSR. These non-power MSR test facilities will require review by the US Nuclear Regulatory Commission (NRC) staff. This report proposes chapter adaptations for NUREG-1537 in the form of interim staff guidance to address preparation and review of molten salt non-power reactor license applications. The proposed adaptations are based on a previous regulatory gap analysis of select chapters from NUREG-1537 for their applicability to non-power MSRs operating with a homogeneous fuel salt mixture.

A thermodynamic description for water, hydrogen fluoride and hydrogen dissolutions in cryolite-base molten salts.

PubMed

Wang, Kun; Chartrand, Patrice

2018-06-15

This paper presents a quantitative thermodynamic description for water, hydrogen fluoride and hydrogen dissolutions in cryolite-base molten salts, which is of technological importance to the Hall-Héroult electrolytic aluminum extraction cell. The Modified Quasichemical Model in the Quadruplet Approximation (MQMQA), as used to treat a large variety of molten salt systems, was adopted to thermodynamically describe the present liquid phase; all solid solutions were modeled using the Compound Energy Formalism (CEF); the gas phase was thermodynamically treated as an ideal mixture of all possible species. The model parameters were mainly obtained by critical evaluations and optimizations of thermodynamic and phase equilibrium data available from relative experimental measurements and theoretical predictions (first-principles calculations and empirical estimations) for the lower-order subsystems. These optimized model parameters were thereafter merged within the Kohler/Toop interpolation scheme, facilitating the prediction of gas solubility (H2O, HF and H2) in multicomponent cryolite-base molten salts using the FactSage thermochemical software. Several interesting diagrams were finally obtained in order to provide useful information for the industrial partners dedicated to the Hall-Héroult electrolytic aluminum production or other molten-salt technologies (the purification process and electroslag refining).

Castable Cement Can Prevent Molten-Salt Corrosion in CSP

DOE Office of Scientific and Technical Information (OSTI.GOV)

2016-09-01

NREL's study demonstrated that castable cements on metals are a protective barrier that can prevent permeation of molten salts toward metallic surfaces. The silica-based castable cement Aremco 645-N, when sprayed with boron nitride, can protect containment metallic alloys from attack by molten chlorides at high temperatures (650 degrees C) in short-term tests. Improved thermal energy storage technology could increase the performance of CSP and reduce costs, helping to reach the goal of the U.S. Department of Energy's SunShot Initiative to make solar cost-competitive with other non-renewable sources of electricity by 2020.

Kinetics of Cathode Processes in Separation of Thorium from Molten Salts. Part I. Investigation of ThF$sub 4$ and ThF$sub 4$-CaF$sub 2$; KINETYKA PROCESU KATODOWEGO PRZY OSADZANIU TORU ZE STOPIONYCH SOLI. CZESC I. BADANIA ThF$sub 4$ I ThF$sub 4$-CaF$sub 2$

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mints, S.; Rafal'skii, V.

1961-09-01

The current-intensity curves of non-electrolyzed salts and the curves of time-intensity and current-intensity in electrolyzed salts were plotted for molten ThF/sub 4/ and ThF /sub 4/CaF/sub 2/. The intensity of salt disintegration was determined, and electric conductivity in electrolyte was observed. (trauth)

Behavior of toxic metals and radionuclides during molten salt oxidation of chlorinated plastics.

PubMed

Yang, Hee-Chul; Cho, Yong-Jun; Eun, Hee-Chul; Yoo, Jae-Hyung; Kim, Joon-Hyung

2004-01-01

Molten salt oxidation is one of the promising alternatives to incineration for chlorinated organics without the emission of chlorinated organic pollutants. This study investigated the behavior of three hazardous metals (Cd, Pb, and Cr) and four radioactive metal surrogates (Cs, Ce, Gd, and Sm) in the molten Na2CO3 oxidation reactor during the destruction of PVC plastics. In the tested temperature ranges (1143 1223K) and NaCl content (0-10%), the impact of temperature on the retention of cadmium and lead in the molten salt reactor was very small, but that of the NaCl content for their retention was relatively higher. The influence of NaCl accumulation was, however, proven to be practically negligible due to the low-temperature operating characteristics of the molten salt oxidation system. Neither temperature increase nor chlorine accumulation in the MSO reactor reduced the retention of Cr, Ce, Gd, and Sm. Over 99.98% of these metals remained in the reactor. The influence of the temperature on the cesium behavior is relatively large for a chlorine addition, however, over 99.7% of cesium remained in the reactor throughout the entire test. The experimental metal entrainment rate and the entrained metal particle size distribution agree well with the theoretical equilibrium metal distributions.

Monte Carlo study of molten salt with charge asymmetry near the electrode surface.

PubMed

Kłos, Jacek; Lamperski, Stanisław

2014-02-07

Results of the Monte Carlo simulation of the electrode | molten salt or ionic liquid interface are reported. The system investigated is approximated by the primitive model of electrolyte being in contact with a charged hard wall. Ions differ in charges, namely anions are divalent and cations are monovalent but they are of the same diameter d = 400 pm. The temperature analysis of heat capacity at a constant volume Cv and the anion radial distribution function, g2-/2-, allowed the choice of temperature of the study, which is T = 2800 K and corresponds to T(*) = 0.34 (definition of reduced temperature T(*) in text). The differential capacitance curve of the interface with the molten salt or ionic liquid at c = 5.79 M has a distorted bell shape. It is shown that with increasing electrolyte concentration from c = 0.4 to 5 M the differential capacitance curves undergo transition from U shape to bell shape.

Materials corrosion in molten lithium fluoride-sodium fluoride-potassium fluoride eutectic salt

NASA Astrophysics Data System (ADS)

Olson, Luke Christopher

Static corrosion studies were undertaken to determine the compatibility of several candidate high temperature materials for a heat transfer loop in a molten alkali fluoride eutectic salt, LiF-NaF-KF: 46.5-11.5-42 mol % (commonly referred to as FLiNaK), as well as a molten chloride near eutectic salt, KCl-MgCl2: 68-32 mol %. Several high temperature alloys: Hastelloy-N, Hastelloy-X, Haynes-230, Inconel-617, and Incoloy-800H, Nb-1Zr, a nearly pure Ni alloy Ni-201, and a C/SiSiC ceramic were exposed to molten FLiNaK at 850°C for 500 h in sealed graphite crucibles under an argon cover gas. Corrosion occurred predominantly from dealloying of Cr from the Cr bearing alloys, an effect that was particularly pronounced at the grain boundaries. Corrosion was noted to occur from selective attack of the Si phase in the C/SiSiC ceramic. Alloy weight-loss/area due to molten fluoride salt exposure correlated with the initial Cr-content of the alloys, and was consistent with the Cr-content measured in the salts after corrosion tests. The alloys' weight-loss/area was also found to correlate to the concentration of carbon present in the nominally 20% Cr containing alloys, due to the formation of chromium carbide phases at the grain boundaries. The corrosion mechanisms for the chloride based salt were found to be similar to those observed in FLiNaK, but the chemical attack was found to be less aggressive. Sulfamate Ni electroplating and Mo plasma spraying of Fe-Ni-Cr alloy coupons was investigated to mitigate Cr dissolution. A chemical vapor deposited pyrolytic carbon and SiC coating was also investigated to protect the C/SiSiC composites. Results indicate that Ni-plating has the potential to provide protection against alloy corrosion in molten fluoride salts. Furthermore, the presence of a chromium-oxide interlayer at the interface of the Ni-plating and alloy substrate can further improve the efficacy of the Ni-plating. The pyrolytic carbon and SiC coating on the C/SiSiC composites

Highly efficient lithium composite anode with hydrophobic molten salt in seawater

NASA Astrophysics Data System (ADS)

Zhang, Yancheng; Urquidi-Macdonald, Mirna

A lithium composite anode (lithium/1-butyl-3-methyl-imidazoleum hexafluorophosphate (BMI +PF 6-)/4-VLZ) for primary lithium/seawater semi-fuel-cells is proposed to reduce lithium-water parasitic reaction and, hence, increase the lithium anodic efficiency up to 100%. The lithium composite anode was activated when in contact with artificial seawater (3% NaCl solution) and the output was a stable anodic current density at 0.2 mA/cm 2, which lasted about 10 h under potentiostatic polarization at +0.5 V versus open circuit potential (OCP); the anodic efficiency was indirectly measured to be 100%. With time, a small traces of water diffused through the hydrophobic molten salt, BMI +PF 6-, reached the lithium interface and formed a double layer film (LiH/LiOH). Accordingly, the current density decreased and the anodic efficiency was estimated to be 90%. The hypothesis of small traces of water penetrating the molten salt and reaching the lithium anode—after several hours of operation—is supported by the collected experimental current density and hydrogen evolution, electrochemical impedance spectrum analysis, and non-mechanistic interface film modeling of lithium/BMI +PF 6-.

Na/beta-alumina/NaAlCl4, Cl2/C circulating cell

NASA Technical Reports Server (NTRS)

Cherng, Jing-Yih; Bennion, Douglas N.

1987-01-01

A study was made of a high specific energy battery based on a sodium negative electrode and a chlorine positive electrode with molten AlCl3-NaCl electrolyte and a solid beta alumina separator. The basic performance of a Na beta-alumina NaAlCl4, Cl2/C circulating cell at 200 C was demonstrated. This cell can be started at 150 C. The use of melting sodium chloroaluminate electrolyte overcomes some of the material problems associated with the high working temperatures of present molten salt systems, such as Na/S and LiAl/FeS, and retains the advantages of high energy density and relatively efficient electrode processes. Preliminary investigations were conducted on a sodium-chlorine static cell, material compability, electrode design, wetting, and theoretical calculations to assure a better chance of success before assembling a Na/Cl2 circulating cell. Mathematical models provide a theoretical explanation for the performance of the NaCl2 battery. The results of mathematical models match the experimental results very well. According to the result of the mathematical modeling, an output at 180 mA/sq cm and 3.2 V can be obtained with optimized cell design.

Chemical Safety: Molten Salt Baths Cited as Lab Hazards.

ERIC Educational Resources Information Center

Baum, Rudy

1982-01-01

Discusses danger of explosions with molten salts baths, commonly used as heat-transfer media. One such explosion involved use of a bath containing 3-lb sodium nitrite and 1-lb potassium thiocyanate. Although most commercially available mixtures for heat transfer contain oxidizers, a reducer (thiocyanate) was included which possibly triggered the…

Development of Molten-Salt Heat Transfer Fluid Technology for Parabolic Trough Solar Power Plants - Public Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grogan, Dylan C. P.

2013-08-15

Executive Summary This Final Report for the "Development of Molten-Salt Heat Transfer Fluid (HTF) Technology for Parabolic Trough Solar Power Plants” describes the overall project accomplishments, results and conclusions. Phase 1 analyzed the feasibility, cost and performance of a parabolic trough solar power plant with a molten salt heat transfer fluid (HTF); researched and/or developed feasible component options, detailed cost estimates and workable operating procedures; and developed hourly performance models. As a result, a molten salt plant with 6 hours of storage was shown to reduce Thermal Energy Storage (TES) cost by 43.2%, solar field cost by 14.8%, and levelizedmore » cost of energy (LCOE) by 9.8% - 14.5% relative to a similar state-of-the-art baseline plant. The LCOE savings range met the project’s Go/No Go criteria of 10% LCOE reduction. Another primary focus of Phase 1 and 2 was risk mitigation. The large risk areas associated with a molten salt parabolic trough plant were addressed in both Phases, such as; HTF freeze prevention and recovery, collector components and piping connections, and complex component interactions. Phase 2 analyzed in more detail the technical and economic feasibility of a 140 MWe,gross molten-salt CSP plant with 6 hours of TES. Phase 2 accomplishments included developing technical solutions to the above mentioned risk areas, such as freeze protection/recovery, corrosion effects of applicable molten salts, collector design improvements for molten salt, and developing plant operating strategies for maximized plant performance and freeze risk mitigation. Phase 2 accomplishments also included developing and thoroughly analyzing a molten salt, Parabolic Trough power plant performance model, in order to achieve the project cost and performance targets. The plant performance model and an extensive basic Engineering, Procurement, and Construction (EPC) quote were used to calculate a real levelized cost of energy (LCOE) of 11.50�

In Situ Production of Copper Oxide Nanoparticles in a Binary Molten Salt for Concentrated Solar Power Plant Applications.

PubMed

Lasfargues, Mathieu; Stead, Graham; Amjad, Muhammad; Ding, Yulong; Wen, Dongsheng

2017-05-19

Seeding nanoparticles in molten salts has been shown recently as a promising way to improve their thermo-physical properties. The prospect of such technology is of interest to both academic and industrial sectors in order to enhance the specific heat capacity of molten salt. The latter is used in concentrated solar power plants as both heat transfer fluid and sensible storage. This work explores the feasibility of producing and dispersing nanoparticles with a novel one pot synthesis method. Using such a method, CuO nanoparticles were produced in situ via the decomposition of copper sulphate pentahydrate in a KNO₃-NaNO₃ binary salt. Analyses of the results suggested preferential disposition of atoms around produced nanoparticles in the molten salt. Thermal characterization of the produced nano-salt suspension indicated the dependence of the specific heat enhancement on particle morphology and distribution within the salts.

Electrochemical preparation of single-crystalline Cr 2O 3 from molten salts

NASA Astrophysics Data System (ADS)

Abe, Hideki; Nishida, Kenji; Imai, Motoharu; Kitazawa, Hideaki

2004-06-01

Single crystals of Cr 2O 3 have been grown by means of electrolysis on a 1:100 stoichiometric mixture of CrO 3 and cesium molybdate, Cs 2MoO 4, fused at 1000°C in an ambient atmosphere. Potentiometric measurements on the molten salts have shown the existence of a critical voltage of -320 mV below which hexagonal platelets-shaped single-crystalline Cr 2O 3 is grown on the surface of the working electrode. Coulometry measurements have revealed that the Cr ions are at their highest oxidation state of Cr +6 in the molten electrolyte, which suggests that the electric reduction of Cr +6 to Cr +3 drives the single-crystal growth of Cr 2O 3.

Prediction of the thermophysical properties of molten salt fast reactor fuel from first-principles

NASA Astrophysics Data System (ADS)

Gheribi, A. E.; Corradini, D.; Dewan, L.; Chartrand, P.; Simon, C.; Madden, P. A.; Salanne, M.

2014-05-01

Molten fluorides are known to show favourable thermophysical properties which make them good candidate coolants for nuclear fission reactors. Here we investigate the special case of mixtures of lithium fluoride and thorium fluoride, which act both as coolant and as fuel in the molten salt fast reactor concept. By using ab initio parameterised polarisable force fields, we show that it is possible to calculate the whole set of properties (density, thermal expansion, heat capacity, viscosity and thermal conductivity) which are necessary for assessing the heat transfer performance of the melt over the whole range of compositions and temperatures. We then deduce from our calculations several figures of merit which are important in helping the optimisation of the design of molten salt fast reactors.

Reversibility of electrochemical reactions of sulfur supported on inverse opal carbon in glyme-Li salt molten complex electrolytes.

PubMed

Tachikawa, Naoki; Yamauchi, Kento; Takashima, Eriko; Park, Jun-Woo; Dokko, Kaoru; Watanabe, Masayoshi

2011-07-28

Electrochemical reactions of sulfur supported on three-dimensionally ordered macroporous carbon in glyme-Li salt molten complex electrolytes exhibit good reversibility and large capacity based on the mass of sulfur, which suggests that glyme-Li salt molten complexes are suitable electrolytes for Li-S batteries.

Molten Salt Synthesis and Structural Characterization of BaTiO3 Nanocrystal Ceramics

NASA Astrophysics Data System (ADS)

Ahda, S.; Misfadhila, S.; Parikin, P.; Putra, T. Y. S. P.

2017-02-01

A new synthesis route to obtain high-purity barium titanate powder, BaTiO3, using the molten salt method by reacting the raw materials (BaCO3 and TiO2) in an atmosphere of molten NaCl and KCl, has been developed. The synthesized BaTiO3 ceramic particles have been successfully carried out at the sintering temperature 950°C for 4 hours. The Rietveld refinement of the XRD diffraction patterns was employed to characterize the structural information of the nanocrystalline BaTiO3 ceramics. The lattice parameters (a=4.0043 Å, b=4.0308Å with space group P4mm) of tetragonal perovskite structure, as an indication of piezoelectric characteristics, have been successfully determined by the Rietveld refinement. While the crystallitte particle size and strains have been obtained for the values of 110.6 nm and 0.74 % respectively

Integrated In Situ Characterization of a Molten Salt Catalyst Surface: Evidence of Sodium Peroxide and Hydroxyl Radical Formation

PubMed Central

Khan, Abdulaziz M.; Tang, Yu; Nguyen, Luan; Ziani, Ahmed; Jacobs, Benjamin W.; Elbaz, Ayman M.; Sarathy, S. Mani; Tao, Franklin (Feng)

2017-01-01

Abstract Sodium‐based catalysts (such as Na2WO4) were proposed to selectively catalyze OH radical formation from H2O and O2 at high temperatures. This reaction may proceed on molten salt state surfaces owing to the lower melting point of the used Na salts compared to the reaction temperature. This study provides direct evidence of the molten salt state of Na2WO4, which can form OH radicals, using in situ techniques including X‐ray diffraction (XRD), scanning transmission electron microscopy (STEM), laser induced fluorescence (LIF) spectrometry, and ambient‐pressure X‐ray photoelectron spectroscopy (AP‐XPS). As a result, Na2O2 species, which were hypothesized to be responsible for the formation of OH radicals, have been identified on the outer surfaces at temperatures of ≥800 °C, and these species are useful for various gas‐phase hydrocarbon reactions, including the selective transformation of methane to ethane. PMID:28650565

Integrated In Situ Characterization of a Molten Salt Catalyst Surface: Evidence of Sodium Peroxide and Hydroxyl Radical Formation

DOE PAGES

Takanabe, Kazuhiro; Khan, Abdulaziz M.; Tang, Yu; ...

2017-07-24

Sodium-based catalysts (such as Na 2 WO 4) were proposed to selectively catalyze OH radical formation from H 2O and O 2 at high temperatures. This reaction may proceed on molten salt state surfaces owing to the lower melting point of the used Na salts compared to the reaction temperature. This study provides direct evidence of the molten salt state of Na 2WO 4, which can form OH radicals, using in situ techniques including X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), laser induced fluorescence (LIF) spectrometry, and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS). As a result, Na 2O 2 species,more » which were hypothesized to be responsible for the formation of OH radicals, have been identified on the outer surfaces at temperatures of ≥800°C, and these species are useful for various gasphase hydrocarbon reactions, including the selective transformation of methane to ethane.« less

In Situ Production of Copper Oxide Nanoparticles in a Binary Molten Salt for Concentrated Solar Power Plant Applications

PubMed Central

Lasfargues, Mathieu; Stead, Graham; Amjad, Muhammad; Ding, Yulong; Wen, Dongsheng

2017-01-01

Seeding nanoparticles in molten salts has been shown recently as a promising way to improve their thermo-physical properties. The prospect of such technology is of interest to both academic and industrial sectors in order to enhance the specific heat capacity of molten salt. The latter is used in concentrated solar power plants as both heat transfer fluid and sensible storage. This work explores the feasibility of producing and dispersing nanoparticles with a novel one pot synthesis method. Using such a method, CuO nanoparticles were produced in situ via the decomposition of copper sulphate pentahydrate in a KNO3-NaNO3 binary salt. Analyses of the results suggested preferential disposition of atoms around produced nanoparticles in the molten salt. Thermal characterization of the produced nano-salt suspension indicated the dependence of the specific heat enhancement on particle morphology and distribution within the salts. PMID:28772910

13. VIEW OF THE MOLTEN SALT BATHS USED TO UNIFORMLY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. VIEW OF THE MOLTEN SALT BATHS USED TO UNIFORMLY AND QUICKLY HEAT METALS PRIOR TO WORKING (ROLLING). (9/16/85) - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

Hydrated multivalent cations are new class of molten salt mixtures

NASA Technical Reports Server (NTRS)

Angell, C. A.

1967-01-01

Electrical conductance and activation energy measurements on mixtures of calcium and potassium nitrate show the hydrated form to be a new class of molten salt. The theoretical glass transition temperature of the hydrate varied in a manner opposite to that of the anhydrous system.

Electrosynthesis of cerium hexaboride by the molten salt technique

NASA Astrophysics Data System (ADS)

Amalajyothi, K.; Berchmans, L. John; Angappan, S.; Visuvasam, A.

2008-07-01

Molten salts are well thought-out as the incredibly promising medium for chemical and electrochemical synthesis of compounds. Hence a stab has been made on the electrochemical synthesis of CeB 6 using molten salt technique. The electrolyte consisted of lithium fluoride (LiF), boron trioxide (B 2O 3) and cerium chloride (CeCl 3). Electrochemical experiments were carried out in an inconal reactor in an argon atmosphere. Electrolysis was executed in a high-density graphite crucible, which doles out as the electrolyte clutching vessel as well as the anode. The cathode was made up of a molybdenum rod. The electrolysis was carried out at 900 °C at different current densities intended for the synthesis of CeB 6 crystals. After the electrolysis, the cathode product was removed and cleaned using dilute HCl solution. The crystals were scrutinized by X-ray diffraction (XRD) to make out the phase and the purity. It has been observed that CeB 6 crystals are synthesized at all current densities and the product has traces of impurities.

An experimental test plan for the characterization of molten salt thermochemical properties in heat transport systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pattrick Calderoni

2010-09-01

Molten salts are considered within the Very High Temperature Reactor program as heat transfer media because of their intrinsically favorable thermo-physical properties at temperatures starting from 300 C and extending up to 1200 C. In this context two main applications of molten salt are considered, both involving fluoride-based materials: as primary coolants for a heterogeneous fuel reactor core and as secondary heat transport medium to a helium power cycle for electricity generation or other processing plants, such as hydrogen production. The reference design concept here considered is the Advanced High Temperature Reactor (AHTR), which is a large passively safe reactormore » that uses solid graphite-matrix coated-particle fuel (similar to that used in gas-cooled reactors) and a molten salt primary and secondary coolant with peak temperatures between 700 and 1000 C, depending upon the application. However, the considerations included in this report apply to any high temperature system employing fluoride salts as heat transfer fluid, including intermediate heat exchangers for gas-cooled reactor concepts and homogenous molten salt concepts, and extending also to fast reactors, accelerator-driven systems and fusion energy systems. The purpose of this report is to identify the technical issues related to the thermo-physical and thermo-chemical properties of the molten salts that would require experimental characterization in order to proceed with a credible design of heat transfer systems and their subsequent safety evaluation and licensing. In particular, the report outlines an experimental R&D test plan that would have to be incorporated as part of the design and operation of an engineering scaled facility aimed at validating molten salt heat transfer components, such as Intermediate Heat Exchangers. This report builds on a previous review of thermo-physical properties and thermo-chemical characteristics of candidate molten salt coolants that was generated as

Corrosion-induced microstructural developments in 316 stainless steel during exposure to molten Li2BeF4(FLiBe) salt

NASA Astrophysics Data System (ADS)

Zheng, Guiqiu; He, Lingfeng; Carpenter, David; Sridharan, Kumar

2016-12-01

The microstructural developments in the near-surface regions of AISI 316 stainless steel during exposure to molten Li2BeF4 (FLiBe) salt have been investigated with the goal of using this material for the construction of the fluoride salt-cooled high-temperature reactor (FHR), a leading nuclear reactor concept for the next generation nuclear plants (NGNP). Tests were conducted in molten FLiBe salt (melting point: 459 °C) at 700 °C in graphite crucibles and 316 stainless steel crucibles for exposure duration of up to 3000 h. Corrosion-induced microstructural changes in the near-surface regions of the samples were characterized using scanning electron microscopy (SEM) in conjunction with energy dispersive x-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD), and scanning transmission electron microscopy (STEM) with EDS capabilities. Intergranular corrosion attack in the near-surface regions was observed with associated Cr depletion along the grain boundaries. High-angle grain boundaries (15-180°) were particularly prone to intergranular attack and Cr depletion. The depth of attack extended to the depths of 22 μm after 3000-h exposure for the samples tested in graphite crucible, while similar exposure in 316 stainless steel crucible led to the attack depths of only about 11 μm. Testing in graphite crucibles led to the formation of nanometer-scale Mo2C, Cr7C3 and Al4C3 particle phases in the near-surface regions of the material. The copious depletion of Cr in the near-surface regions induced a γ-martensite to α-ferrite phase (FeNix) transformation. Based on the microstructural analysis, a thermal diffusion controlled corrosion model was developed and experimentally validated for predicting long-term corrosion attack depth.

Molten salt corrosion behavior of structural materials in LiCl-KCl-UCl3 by thermogravimetric study

NASA Astrophysics Data System (ADS)

Rao, Ch Jagadeeswara; Ningshen, S.; Mallika, C.; Mudali, U. Kamachi

2018-04-01

The corrosion resistance of structural materials has been recognized as a key issue in the various unit operations such as salt purification, electrorefining, cathode processing and injection casting in the pyrochemical reprocessing of spent metallic nuclear fuels. In the present work, the corrosion behavior of the candidate materials of stainless steel (SS) 410, 2.25Cr-1Mo and 9Cr-1Mo steels was investigated in molten LiCl-KCl-UCl3 salt by thermogravimetric analysis under inert and reactive atmospheres at 500 and 600 °C, for 6 h duration. Insignificant weight gain (less than 1 mg/cm2) in the inert atmosphere and marginal weight gain (maximum 5 mg/cm2) in the reactive atmosphere were observed at both the temperatures. Chromium depletion rates and formation of Cr-rich corrosion products increased with increasing temperature of exposure in both inert and reactive atmospheres as evidenced by SEM and EDS analysis. The corrosion attack by LiCl-KCl-UCl3 molten salt, under reactive atmosphere for 6 h duration was more in the case of SS410 than 9Cr-1Mo steel followed by 2.25Cr-1Mo steel at 500 °C and the corrosion attack at 600 °C followed the order: 9Cr-1Mo steel >2.25Cr-1Mo steel > SS410. Outward diffusion of the minor alloying element, Mo was observed in 9Cr-1Mo and 2.25Cr-1Mo steels at both temperatures under reactive atmosphere. Laser Raman spectral analysis of the molten salt corrosion tested alloys under a reactive atmosphere at 500 and 600 °C for 6 h revealed the formation of unprotected Fe3O4 and α-as well as γ-Fe2O3. The results of the present study facilitate the selection of structural materials for applications in the corrosive molten salt environment at high temperatures.

Electrical conductivity and molten salt corrosion behavior of spinel nickel ferrite

NASA Astrophysics Data System (ADS)

Liu, Baogang; Zhang, Lei; Zhou, Kechao; Li, Zhiyou; Wang, Hao

2011-08-01

Nickel ferrite was prepared by solid-state reaction at 1300 °C as inert anode for aluminum electrolysis. DC conductivities and molten salt corrosion behavior of the samples were investigated in detail regarding the effects of different sintering atmospheres. X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis were used to analyse the phase compositions and microstructures. The DC conductivities of the samples sintered in nitrogen showed a drastic increase compared to those sintered in air, and at 960 °C they increased from 1.94 S/cm to 22.65 S/cm. The samples sintered in nitrogen showed much better corrosion resistance than those sintered in air, attributing to the formation of the dense protective layers in the anode surfaces during the electrolysis at 960 °C. The conductive mechanism and molten salt corrosion behavior were also discussed.

Thermal performance analysis of a thermocline thermal energy storage system with FLiNaK molten salt

NASA Astrophysics Data System (ADS)

Liu, C.; Cheng, M. S.; Zhao, B. C.; Dai, Z. M.

2017-01-01

A thermocline thermal storage unit with a heat transfer fluid (HTF) of high-temperature molten salt is considered as one of the most promising methods of thermal storage due to its lower cost and smaller size. The main objective of this work is to analyze the transient behavior of the available molten salt FLiNaK used as the HTF in heat transfer and heat storage in a thermocline thermal energy storage (TES) system. Thermal characteristics including temperature profiles influenced by different inlet velocities of HTF and different void fractions of porous heat storage medium are analyzed. The numerical investigation on the heat storage and heat transfer characteristics of FLiINaK has been carried out. A comparison between two different molten salts, FLiNaK and Hitec, has been explored in this paper with regards to their charging and discharging operations. The results indicate the system with FLiNaK has a greater energy storage capability, a shorter charging time and a higher output power. The numerical investigation reveals heat storage and heat transfer characteristics of the thermocline TES system with FLiNaK, and provide important references for molten salt selection of the TES system in the future.

Porous membrane electrochemical cell for uranium and transuranic recovery from molten salt electrolyte

DOEpatents

Willit, James L [Ratavia, IL

2007-09-11

An improved process and device for the recovery of the minor actinides and the transuranic elements (TRU's) from a molten salt electrolyte. The process involves placing the device, an electrically non-conducting barrier between an anode salt and a cathode salt. The porous barrier allows uranium to diffuse between the anode and cathode, yet slows the diffusion of uranium ions so as to cause depletion of uranium ions in the catholyte. This allows for the eventual preferential deposition of transuranics present in spent nuclear fuel such as Np, Pu, Am, Cm. The device also comprises an uranium oxidation anode. The oxidation anode is solid uranium metal in the form of spent nuclear fuel. The spent fuel is placed in a ferric metal anode basket which serves as the electrical lead or contact between the molten electrolyte and the anodic uranium metal.

Porous membrane electrochemical cell for uranium and transuranic recovery from molten salt electrolyte

DOEpatents

Willit, James L [Batavia, IL

2010-09-21

An improved process and device for the recovery of the minor actinides and the transuranic elements (TRU's) from a molten salt electrolyte. The process involves placing the device, an electrically non-conducting barrier between an anode salt and a cathode salt. The porous barrier allows uranium to diffuse between the anode and cathode, yet slows the diffusion of uranium ions so as to cause depletion of uranium ions in the catholyte. This allows for the eventual preferential deposition of transuranics present in spent nuclear fuel such as Np, Pu, Am, Cm. The device also comprises an uranium oxidation anode. The oxidation anode is solid uranium metal in the form of spent nuclear fuel. The spent fuel is placed in a ferric metal anode basket which serves as the electrical lead or contact between the molten electrolyte and the anodic uranium metal.

EXPERIMENTAL MOLTEN-SALT-FUELED 30-Mw POWER REACTOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexander, L.G.; Kinyon, B.W.; Lackey, M.E.

1960-03-24

A preliminary design study was made of an experimental molten-salt- fueled power reactor. The reactor considered is a single-region homogeneous burner coupled with a Loeffler steam-generating cycle. Conceptual plant layouts, basic information on the major fuel circuit components, a process flowsheet, and the nuclear characteristics of the core are presented. The design plant electrical output is 10 Mw, and the total construction cost is estimated to be approximately ,000,000. (auth)

Comparison of corrosion performance of grade 316 and grade 347H stainless steels in molten nitrate salt

NASA Astrophysics Data System (ADS)

Trent, M. C.; Goods, S. H.; Bradshaw, R. W.

2016-05-01

Stainless steel samples machined from SA-312 TP316 and SA-213 TP347H pipe were exposed to a molten nitrate salt environment at 600°C (1112°F) for up to 3000 hours in order to generate corrosion rates for use in concentrated solar power (CSP) facilities. Descaled weight loss measurements were made at 1000, 2000, and 3000 hours, with optical and scanning electron microscopy being performed on samples at the longest exposure time. The 316 and 347H alloys exhibited metal losses of 4.4 and 4.8 um respectively at 3000 hours. A linear fit to the data sets yielded annualized metal loss rates of 8.4 and 8.8 um/yr. The oxides were relatively uniform in thickness and multilayered. The inner layer consisted of a (Fe, Cr)-spinel with appreciable amounts of Mn while the outer layer was an oxide composed of only Fe. No pitting, intergranular attack, or other localized attack was found, despite the presence of a sensitized microstructure in both alloys and chloride impurity in the salt mixture. The observations presented here indicate that the two alloys perform quite comparably with respect to molten salt-induced corrosion and in that regard; either would be expected to perform satisfactorily in the intended application.

Thorium and Molten Salt Reactors: Essential Questions for Classroom Discussions

NASA Astrophysics Data System (ADS)

DiLisi, Gregory A.; Hirsch, Allison; Murray, Meredith; Rarick, Richard

2018-04-01

A little-known type of nuclear reactor called the "molten salt reactor" (MSR), in which nuclear fuel is dissolved in a liquid carrier salt, was proposed in the 1940s and developed at the Oak Ridge National Laboratory in the 1960s. Recently, the MSR has generated renewed interest as a remedy for the drawbacks associated with conventional uranium-fueled light-water reactors (LWRs) in use today. Particular attention has been given to the "thorium molten salt reactor" (TMSR), an MSR engineered specifically to use thorium as its fuel. The purpose of this article is to encourage the TPT community to incorporate discussions of MSRs and the thorium fuel cycle into courses such as "Physics and Society" or "Frontiers of Physics." With this in mind, we piloted a pedagogical approach with 27 teachers in which we described the underlying physics of the TMSR and posed five essential questions for classroom discussions. We assumed teachers had some preexisting knowledge of nuclear reactions, but such prior knowledge was not necessary for inclusion in the classroom discussions. Overall, our material was perceived as a real-world example of physics, fit into a standards-based curriculum, and filled a need in the teaching community for providing unbiased references of alternative energy technologies.

Improving molten fluoride salt and Xe135 barrier property of nuclear graphite by phenolic resin impregnation process

NASA Astrophysics Data System (ADS)

He, Zhao; Lian, Pengfei; Song, Yan; Liu, Zhanjun; Song, Jinliang; Zhang, Junpeng; Feng, Jing; Yan, Xi; Guo, Quangui

2018-02-01

A densification process has been conducted on isostatic graphite (IG-110, TOYO TANSO CO., Ltd., Japan) by impregnating phenolic resin to get the densified isostatic graphite (D-IG-110) with pore diameter of nearly 11 nm specifically for molten salt reactor application. The microstructure, mechanical, thermophysical and other properties of graphite were systematically investigated and compared before and after the densification process. The molten fluoride salt and Xe135 penetration in the graphite were evaluated in a high-pressure reactor and a vacuum device, respectively. Results indicated that D-IG-110 exhibited improved properties including infiltration resistance to molten fluoride salt and Xe135 as compared to IG-110 due to its low porosity of 2.8%, the average pore diameter of 11 nm and even smaller open pores on the surface of the graphite. The fluoride salt infiltration amount of IG-110 was 13.5 wt% under 1.5 atm and tended to be saturated under 3 atm with the fluoride salt occupation of 14.8 wt%. As to the D-IG-110, no salts could be detected even up to 10 atm attempted loading. The helium diffusion coefficient of D-IG-110 was 6.92 × 10-8 cm2/s, significantly less than 1.21 × 10-2 cm2/s of IG-110. If these as-produced properties for impregnated D-IG-110 could be retained during MSR operation, the material could prove effective at inhibiting molten fluoride salt and Xe135 inventories in the graphite.

Integrated In Situ Characterization of a Molten Salt Catalyst Surface: Evidence of Sodium Peroxide and Hydroxyl Radical Formation.

PubMed

Takanabe, Kazuhiro; Khan, Abdulaziz M; Tang, Yu; Nguyen, Luan; Ziani, Ahmed; Jacobs, Benjamin W; Elbaz, Ayman M; Sarathy, S Mani; Tao, Franklin Feng

2017-08-21

Sodium-based catalysts (such as Na 2 WO 4 ) were proposed to selectively catalyze OH radical formation from H 2 O and O 2 at high temperatures. This reaction may proceed on molten salt state surfaces owing to the lower melting point of the used Na salts compared to the reaction temperature. This study provides direct evidence of the molten salt state of Na 2 WO 4 , which can form OH radicals, using in situ techniques including X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), laser induced fluorescence (LIF) spectrometry, and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS). As a result, Na 2 O 2 species, which were hypothesized to be responsible for the formation of OH radicals, have been identified on the outer surfaces at temperatures of ≥800 °C, and these species are useful for various gas-phase hydrocarbon reactions, including the selective transformation of methane to ethane. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

The effect of molten salt on high temperature behavior of stainless steel and titanium alloy with the presence of water vapor

NASA Astrophysics Data System (ADS)

Baharum, Azila; Othman, Norinsan Kamil; Salleh, Emee Marina

2018-04-01

The high temperature oxidation experiment was conducted to study the behavior of titanium alloy Ti6A14V and stainless steel 316 in Na2SO4-50%NaCl + Ar-20%O2 (molten salt) and Na2SO4-50%NaCl + Ar-20%O2 + 12% H2O (molten salt + water vapor) environment at 900°C for 30 hours using horizontal tube furnace. The sample then was investigated using weight change measurement analysis and X-ray diffraction (XRD) analysis to study the weight gained and the phase oxidation that occurred. The weight gained of the titanium alloy was higher in molten salt environment compared to stainless steel due to the rapid growth in the oxide scale but showed almost no change of weight gained upon addition of water vapor. This is due to the alloy was fully oxidized. Stainless steel showed more protection and better effect in molten salt environment compared to mixed environment showed by slower weight gain and lower oxidation rate. Meanwhile, the phase oxidation test of the samples showed that the titanium alloy consist of multi oxide layer of rutile (TiO2) and Al2O3 on the surface of the exposed sample. While stainless steel show the formation of both protective Cr-rich oxide and non-protective Fe-rich oxide layer. This can be concluded that stainless steel is better compared to Ti alloy due to slow growing of chromia oxide. Therefore it is proven that stainless steel has better self-protection upon high temperature exposure.

Concentrating Solar Power Projects - Dacheng Dunhuang 50MW Molten Salt

Science.gov Websites

project Status Date: September 29, 2016 Project Overview Project Name: Dacheng Dunhuang 50MW Molten Salt ., Ltd Technology: Linear Fresnel reflector Turbine Capacity: Net: 50.0 MW Gross: 50.0 MW Status: Under reflector Status: Under development Country: China City: Dunhuang Region: Gansu Province Contact(s

Concentrating Solar Power Projects - Chabei 64MW Molten Salt Parabolic

Science.gov Websites

project Status Date: September 29, 2016 Project Overview Project Name: Chabei 64MW Molten Salt Parabolic Technology: Parabolic trough Turbine Capacity: Net: 64.0 MW Gross: 64.0 MW Status: Under development Do you have more information, corrections, or comments? Background Technology: Parabolic trough Status: Under

Thermal conductivity of molten salt mixtures: Theoretical model supported by equilibrium molecular dynamics simulations.

PubMed

Gheribi, Aïmen E; Chartrand, Patrice

2016-02-28

A theoretical model for the description of thermal conductivity of molten salt mixtures as a function of composition and temperature is presented. The model is derived by considering the classical kinetic theory and requires, for its parametrization, only information on thermal conductivity of pure compounds. In this sense, the model is predictive. For most molten salt mixtures, no experimental data on thermal conductivity are available in the literature. This is a hindrance for many industrial applications (in particular for thermal energy storage technologies) as well as an obvious barrier for the validation of the theoretical model. To alleviate this lack of data, a series of equilibrium molecular dynamics (EMD) simulations has been performed on several molten chloride systems in order to determine their thermal conductivity in the entire range of composition at two different temperatures: 1200 K and 1300 K. The EMD simulations are first principles type, as the potentials used to describe the interactions have been parametrized on the basis of first principle electronic structure calculations. In addition to the molten chlorides system, the model predictions are also compared to a recent similar EMD study on molten fluorides and with the few reliable experimental data available in the literature. The accuracy of the proposed model is within the reported numerical and/or experimental errors.

Electrochemical Nucleation and Growth of Uranium and Plutonium from Molten Salts

DOE PAGES

Tylka, M. M.; Willit, J. L.; Williamson, M. A.

2017-07-18

This work examines the nucleation and growth behavior of uranium and plutonium from molten LiCl-KCl eutectic on inert electrodes using electrochemical techniques. Current-time transients obtained from chronoamperometric experiments were compared with theoretical models to characterize the type of nucleation (progressive or instantaneous) for deposition of U and Pu, and co-deposition of U-Pu, from molten LiCl-KCl at inert electrodes. It was established that the nucleation mode of actinides present as chlorides in molten chloride salts changes from progressive to instantaneous with an increasing concentration of the trivalent actinide ions in the salt. The effect of the material of the working electrodemore » was investigated, and it was found that changing the material from tungsten to silver improves resolvability of the nucleation peaks and allows more accurate analysis of the experimental measurements. Using the nucleation data, diffusion coefficients were obtained for U 3+ and Pu 3+, and were found to be in very good agreement with the values obtained from other studies. Furthermore, the density of nuclei produced during instantaneous nucleation, the rate of nucleation for progressive nucleation, and the radius of the deposited nuclei were evaluated and examined at different overpotentials.« less

A Rechargeable High-Temperature Molten Salt Iron-Oxygen Battery.

PubMed

Peng, Cheng; Guan, Chengzhi; Lin, Jun; Zhang, Shiyu; Bao, Hongliang; Wang, Yu; Xiao, Guoping; Chen, George Zheng; Wang, Jian-Qiang

2018-06-11

The energy and power density of conventional batteries are far lower than their theoretical expectations, primarily because of slow reaction kinetics that are often observed under ambient conditions. Here we describe a low-cost and high-temperature rechargeable iron-oxygen battery containing a bi-phase electrolyte of molten carbonate and solid oxide. This new design merges the merits of a solid-oxide fuel cell and molten metal-air battery, offering significantly improved battery reaction kinetics and power capability without compromising the energy capacity. The as-fabricated battery prototype can be charged at high current density, and exhibits excellent stability and security in the highly charged state. It typically exhibits specific energy, specific power, energy density, and power density of 129.1 Wh kg -1 , 2.8 kW kg -1 , 388.1 Wh L -1 , and 21.0 kW L -1 , respectively, based on the mass and volume of the molten salt. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molten salt synthesis and luminescent properties of YVO4:Ln (Ln = Eu3+, Dy3+) nanophosphors.

PubMed

Liu, Chenglu; Wang, Fang; Jia, Peiyun; Lin, Jun; Zhou, Zhiqiang

2012-01-01

Eu3+ and Dy(3+)-doped YVO4 nanocrystallites were successfully prepared at 400 degrees C in equal moles of NaNO3 and KNO3 molten salts. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, transmission electronic microscopy (TEM), photoluminescence (PL) spectrum and lifetime were used to characterize the nanocrystallites. XRD results demonstrate that NaOH concentration and annealing temperature play important roles in phase purity and crystallinity of the nanocrystallites, the optimum NaOH concentration and annealing temperature being 6:40 and 400 degrees C respectively. TEM micrographs show the nanocrystallites are well crystallized with a cubic morphology in an average grain size of about 18 nm. Upon excitation of the vanadate group at 314 nm, YVO4:Eu3+ and YVO4:Dy3+ nanocrystallites exhibit the characteristic emission of Eu3+ and Dy3+, which indicates that there is an energy transfer from the vanadate group to the rare earth ions. Moreover, the structure and luminescent properties of the nanocrystallites were compared with their bulk counterparts with same composition in detail.

Corrosion Behavior of Yttria-Stabilized Zirconia-Coated 9Cr-1Mo Steel in Molten UCl3-LiCl-KCl Salt

NASA Astrophysics Data System (ADS)

Jagadeeswara Rao, Ch.; Venkatesh, P.; Prabhakara Reddy, B.; Ningshen, S.; Mallika, C.; Kamachi Mudali, U.

2017-02-01

For the electrorefining step in the pyrochemical reprocessing of spent metallic fuels of future sodium cooled fast breeder reactors, 9Cr-1Mo steel has been proposed as the container material. The electrorefining process is carried out using 5-6 wt.% UCl3 in LiCl-KCl molten salt as the electrolyte at 500 °C under argon atmosphere. In the present study, to protect the container vessel from hot corrosion by the molten salt, 8-9% yttria-stabilized zirconia (YSZ) ceramic coating was deposited on 9Cr-1Mo steel by atmospheric plasma spray process. The hot corrosion behavior of YSZ-coated 9Cr-1Mo steel specimen was investigated in molten UCl3-LiCl-KCl salt at 600 °C for 100-, 500-, 1000- and 2000-h duration. The results revealed that the weight change in the YSZ-coated specimen was insignificant even after exposure to molten salt for 2000 h, and delamination of coating did not occur. SEM examination showed the lamellar morphology of the YSZ coating after the corrosion test with occluded molten salt. The XRD analysis confirmed the presence of tetragonal and cubic phases of ZrO2, without any phase change. Formation of UO2 in some regions of the samples was evident from XRD results.

Cooling molten salt reactors using "gas-lift"

NASA Astrophysics Data System (ADS)

Zitek, Pavel; Valenta, Vaclav; Klimko, Marek

2014-08-01

This study briefly describes the selection of a type of two-phase flow, suitable for intensifying the natural flow of nuclear reactors with liquid fuel - cooling mixture molten salts and the description of a "Two-phase flow demonstrator" (TFD) used for experimental study of the "gas-lift" system and its influence on the support of natural convection. The measuring device and the application of the TDF device is described. The work serves as a model system for "gas-lift" (replacing the classic pump in the primary circuit) for high temperature MSR planned for hydrogen production. An experimental facility was proposed on the basis of which is currently being built an experimental loop containing the generator, separator bubbles and necessary accessories. This loop will model the removal of gaseous fission products and tritium. The cleaning of the fuel mixture of fluoride salts eliminates problems from Xenon poisoning in classical reactors.

Heat capacity of molten halides.

PubMed

Redkin, Alexander A; Zaikov, Yurii P; Korzun, Iraida V; Reznitskikh, Olga G; Yaroslavtseva, Tatiana V; Kumkov, Sergey I

2015-01-15

The heat capacities of molten salts are very important for their practical use. Experimental investigation of this property is challenging because of the high temperatures involved and the corrosive nature of these materials. It is preferable to combine experimental investigations with empirical relationships, which allows for the evaluation of the heat capacity of molten salt mixtures. The isobaric molar heat capacities of all molten alkali and alkaline-earth halides were found to be constant for each group of salts. The value depends on the number of atoms in the salt, and the molar heat capacity per atom is constant for all molten halide salts with the exception of the lithium halides. The molar heat capacities of molten halides do not change when the anions are changed.

Calculation of activities of ions in molten salts with potential application to the pyroprocessing of nuclear waste.

PubMed

Salanne, Mathieu; Simon, Christian; Turq, Pierre; Madden, Paul A

2008-01-31

The ability to separate fission products by electrodeposition from molten salts depends, in part, on differences between the interactions of the different fission product cations with the ions present in the molten salt "solvent". These differences may be expressed as ratios of activity coefficients, which depend on the identity of the solvent and other factors. Here, we demonstrate the ability to calculate these activity coefficient ratios using molecular dynamics simulations with sufficient precision to guide the choice of suitable solvent systems in practical applications. We use polarizable ion interaction potentials which have previously been shown to give excellent agreement with structural, transport, and spectroscopic information of the molten salts, and the activity coefficients calculated in this work agree well with experimental data. The activity coefficients are shown to vary systematically with cation size for a set of trivalent cations.

High-temperature molten salt solar thermal systems

NASA Astrophysics Data System (ADS)

Copeland, R. J.; Leach, J. W.; Stern, G.

Conceptual designs of a solar thermal central receiver and a thermal storage subsystem were analyzed to estimate thermal losses and to assess the economics of high-temperature applications with molten salt transport fluids. Modifications to a receiver design being developed by the Martin Marietta Corporation were studied to investigate possible means for improving efficiency at high temperatures. Computations were made based on conceptual design of internally insulated high temperature storage tanks to estimate cost and performance. A study of a potential application of the system for thermochemical production of hydrogen indicates that thermal storage at 1100 C will be economically attractive.

In situ NMR spectroscopy: inulin biomass conversion in ZnCl₂ molten salt hydrate medium-SnCl₄ addition controls product distribution.

PubMed

Wang, Yingxiong; Pedersen, Christian Marcus; Qiao, Yan; Deng, Tiansheng; Shi, Jing; Hou, Xianglin

2015-01-22

The dehydration of inulin biomass to the platform chemicals, 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA), in ZnCl2 molten salt hydrate medium was investigated. The influence of the Lewis acid catalyst, SnCl4, on the product distribution was examined. An in situ(1)H NMR technique was employed to follow the reaction at the molecular level. The experimental results revealed that only 5-HMF was obtained from degradation of inulin biomass in ZnCl2 molten salt hydrate medium, while the LA was gradually becoming the main product when the reaction temperature was increased in the presence of the Lewis acid catalyst SnCl4. In situ NMR spectroscopy could monitor the reaction and give valuable insight. Copyright © 2014 Elsevier Ltd. All rights reserved.

Concentrating Solar Power Projects - Golden Tower 100MW Molten Salt project

Science.gov Websites

| Concentrating Solar Power | NREL Golden Tower 100MW Molten Salt project Status Date Turbine Capacity: Net: 100.0 Gross: 100.0 Status: Under development Do you have more information , corrections, or comments? Background Technology: Power tower Status: Under development Country: China City

An Investigation on the Thermophysical Properties of a Binary Molten Salt System Containing Both Aluminum Oxide and Titanium Oxide Nanoparticle Suspensions

NASA Astrophysics Data System (ADS)

Giridhar, Kunal

Molten salts are showing great potential to replace current heat transfer and thermal energy storage fluids in concentrated solar plants because of their capability to maximize thermal energy storage, greater stability, cost effectiveness and significant thermal properties. However one of the major drawbacks of using molten salt as heat transfer fluid is that they are in solid state at room temperature and they have a high freezing point. Hence, significant resources would be required to maintain it in liquid form. If molten salt freezes while in operation, it would eventually damage piping network due to its volume shrinkage along with rendering the entire plant inoperable. It is long known that addition of nanoparticle suspensions has led to significant changes in thermal properties of fluids. In this investigation, aluminum oxide and titanium oxide nanoparticles of varying concentrations are added to molten salt/solar salt system consisting of 60% sodium nitrate and 40% potassium nitrate. Using differential scanning calorimeter, an attempt will be made to investigate changes in heat capacity of system, depression in freezing point and changes in latent heat of fusion. Scanning electron microscope will be used to take images of samples to study changes in micro-structure of mixture, ensure uniform distribution of nanoparticle in system and verify authenticity of materials used for experimentation. Due to enormous magnitude of CSP plant, actual implementation of molten salt system is on a large scale. With this investigation, even microscopic enhancement in heat capacity and slight lowering of freezing point will lead to greater benefits in terms of efficiency and cost of operation of plant. These results will further the argument for viability of molten salt as a heat transfer fluid and thermal storage system in CSP. One of the objective of this experimentation is to also collect experimental data which can be used for establishing relation between concentration

The Radiative Heat Transfer Properties of Molten Salts and Their Relevance to the Design of Advanced Reactors

NASA Astrophysics Data System (ADS)

Chaleff, Ethan Solomon

Molten salts, such as the fluoride salt eutectic LiF-NaF-KF (FLiNaK) or the transition metal fluoride salt KF-ZrF4, have been proposed as coolants for numerous advanced reactor concepts. These reactors are designed to operate at high temperatures where radiative heat transfer may play a significant role. If this is the case, the radiative heat transfer properties of the salt coolants are required to be known for heat transfer calculations to be performed accurately. Chapter 1 describes the existing literature and experimental efforts pertaining to radiative heat transfer in molten salts. The physics governing photon absorption by halide salts is discussed first, followed by a more specific description of experimental results pertaining to salts of interest. The phonon absorption edge in LiF-based salts such as FLiNaK is estimated and the technique described for potential use in other salts. A description is given of various spectral measurement techniques which might plausibly be employed in the present effort, as well as an argument for the use of integral techniques. Chapter 2 discusses the mathematical treatments required to approximate and solve for the radiative flux in participating materials. The differential approximation and the exact solutions to the radiative flux are examined, and methods are given to solve radiative and energy equations simultaneously. A coupled solution is used to examine radiative heat transfer to molten salt coolants. A map is generated of pipe diameters, wall temperatures, and average absorption coefficients where radiative heat transfer will increase expected heat transfer by more than 10% compared to convective methods alone. Chapter 3 presents the design and analysis of the Integral Radiative Absorption Chamber (IRAC). The IRAC employs an integral technique for the measurement of the entire electromagnetic spectrum, negating some of the challenges associated with the methods discussed in Chapter 1 at the loss of spectral

A facile molten-salt route to graphene synthesis.

PubMed

Liu, Xiaofeng; Giordano, Cristina; Antonietti, Markus

2014-01-15

Efficient synthetic routes are continuously pursued for graphene in order to implement its applications in different areas. However, direct conversion of simple monomers to graphene through polymerization in a scalable manner remains a major challenge for chemists. Herein, a molten-salt (MS) route for the synthesis of carbon nanostructures and graphene by controlled carbonization of glucose in molten metal chloride is reported. In this process, carbohydrate undergoes polymerization in the presence of strongly interacting ionic species, which leads to nanoporous carbon with amorphous nature and adjustable pore size. At a low precursor concentration, the process converts the sugar molecules (glucose) to rather pure few-layer graphenes. The MS-derived graphenes are strongly hydrophobic and exhibit remarkable selectivity and capacity for absorption of organics. The methodology described may open up a new avenue towards the synthesis and manipulation of carbon materials in liquid media. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization and Thermal Properties of Nitrate Based Molten Salt for Heat Recovery System

NASA Astrophysics Data System (ADS)

Faizal Tukimon, Mohd; Muhammad, Wan Nur Azrina Wan; Nor Annuar Mohamad, Md; Yusof, Farazila

2017-10-01

Molten salt can acts like a storage medium or heat transfer fluid in heat recovery system. Heat transfer fluid is a fluid that has the capability to deliver heat this one side to another while heat recovery system is a system that transfers heat to produce energy. This studies shows about determining the new formulation of different molten nitrate/nitrite salts consisting of LiNO3, KNO2, KNO3 and NaNO2 that give a low temperature of melting point and high average specific heat capacity. Mixed alkaline molten nitrate/nitrite salt can act as a heat transfer fluid due to their advantageous in terms of its properties that feasible in heat recovery system such as high specific heat capacity, low vapour pressure, low cost and wide range of temperature in its application. The mixing of these primary substances will form a new line of quaternary nitrate salt (LiNO3 - KNO2 - KNO3 - NaNO2). The quaternary mixture was heated inside the box furnace at 150°C for four hours and rose up the temperature to 400°C for eight hours to homogenize the mixture. Through heating process, the elements of nitrate/nitrite base were mixed completely. The temperature was then reduced to 115°C for several hours before removing the mixture from the furnace. The melting point of each sample were testified by using thermal gravimetric analysis, TGA/DTA and experiment of determining the specific heat capacity were conducted by using Differential Scanning Calorimeter, DSC. From the result, it is found that the melting point Sample 1 with percentage of weightage (25.4wt% of LiNO3, 33.8wt% of KNO2, 20.7wt% of KNO3 and 20.1wt% of NaNO2) is 94.4°C whereas the average specific heat capacity was 1.0484/g°C while for Sample 3 with percentages of weightage (30.0wt% of LiNO3, 50.2wt% of KNO2, 3.1wt% of KNO3 and 16.7wt% of NaNO2), the melting point is 86.1°C with average specific heat capacity of 0.7274 J/g°C. In the nut shell, the quaternary mixture salts had been a good mixture with good thermal

CeO2-Y2O3-ZrO2 Membrane with Enhanced Molten Salt Corrosion Resistance for Solid Oxide Membrane (SOM) Electrolysis Process

NASA Astrophysics Data System (ADS)

Zou, Xingli; Li, Xin; Shen, Bin; Lu, Xionggang; Xu, Qian; Zhou, Zhongfu; Ding, Weizhong

2017-02-01

Innovative CeO2-Y2O3-ZrO2 membrane has been successfully developed and used in the solid oxide membrane (SOM) electrolysis process for green metallic materials production. The x mol pct ceria/(8- x) mol pct yttria-costabilized zirconia ( xCe(8- x)YSZ, x = 0, 1, 4, or 7) membranes have been fabricated and investigated as the membrane-based inert anodes to control the SOM electroreduction process in molten salt. The characteristics of these fabricated xCe(8- x)YSZ membranes including their corrosion resistances in molten salt and their degradation mechanisms have been systematically investigated and compared. The results show that the addition of ceria in the YSZ-based membrane can inhibit the depletion of yttrium during the SOM electrolysis, which thus makes the ceria-reinforced YSZ-based membranes possess enhanced corrosion resistances to molten salt. The ceria/yttria-costabilized zirconia membranes can also provide reasonable oxygen ion conductivity during electrolysis. Further investigation shows that the newly modified 4Ce4YSZ ceramic membrane has the potential to be used as novel inert SOM anode for the facile and sustainable production of metals/alloys/composites materials such as Si, Ti5Si3, TiC, and Ti5Si3/TiC from their metal oxides precursors in molten CaCl2.

Production of oxygen from lunar soil by molten salt electrolysis

NASA Technical Reports Server (NTRS)

Keller, Rudolf

1989-01-01

A simple approach to utilizing lunar resources proposes to dissolve lunar soil, without or with little beneficiation, in a suitable molten salt and to electrolyze the oxides to oxygen and a metal byproduct. The envisioned process and the required technological advances are discussed. Promising electrolysis conditions have been identified in a recent experimental program to manufacture silicon and aluminum from anorthite.

9. VIEW OF MOLTEN SALT BATH EQUIPMENT AND ROLLER PRESSES ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. VIEW OF MOLTEN SALT BATH EQUIPMENT AND ROLLER PRESSES BEING INSTALLED ON THE WEST SIDE (SIDE B) OF BUILDING 883. SIDE B OF BUILDING 883 WAS USED TO PROCESS ENRICHED URANIUM FROM 1957-66. (1/23/57) - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

Concentrating Solar Power Projects - Gansu Akesai 50MW Molten Salt Trough

Science.gov Websites

project | Concentrating Solar Power | NREL Gansu Akesai 50MW Molten Salt Trough project Status . Technology: Parabolic trough Turbine Capacity: Net: 50.0 MW Gross: 50.0 MW Status: Under development Do you have more information, corrections, or comments? Background Technology: Parabolic trough Status: Under

Application of Molten Salt Reactor Technology to Nuclear Electric Propulsion Mission

NASA Technical Reports Server (NTRS)

Patton, Bruce; Sorensen, Kirk; Rodgers, Stephen L. (Technical Monitor)

2002-01-01

Nuclear electric propulsion (NEP) and planetary surface power missions require reactors that are lightweight, operationally robust, and scalable in power for widely varying scientific mission objectives. Molten salt reactor technology meets all of these requirements and offers an interesting alternative to traditional gas cooled, liquid metal, and heat pipe space reactors.

Solubility of uranium oxide in molten salt electrolysis bath of LiF-BaF2 with LaF3 additive

NASA Astrophysics Data System (ADS)

Alangi, Nagaraj; Mukherjee, Jaya; Gantayet, L. M.

2016-03-01

The solubility of UO2 in the molten mixtures of equimolar LiF-BaF2(1:1) with LaF3 as additive was studied in the range of 1423 K-1523 K. The molten fluoride salt mixture LiF-BaF2 LaF3 was equilibrated with a sintered uranium oxide pellet at 1423 K, 1473 K, 1523 K and the salt samples were collected after equilibration. Studies were conducted in the range of 10%-50% by weight additions of LaF3 in the equimolar LiF-BaF2(1:1) base fluoride salt bath. Solubility of UO2 increased with rise in LaF3 concentration in the molten fluoride in the temperature range of 1423 K-1523 K. At a given concentration of LaF3, the UO2 solubility increased monotonously with temperature. With mixed solvent, when UF4 was added as a replacement of part of LaF3 in LiF-BaF2(1:1)-10 wt% LaF3 and LiF-BaF2(1:1)-30 wt% LaF3, there was an enhancement of solubility of UO2.

Concentrating Solar Power Projects - Yumen 100MW Molten Salt Tower CSP

Science.gov Websites

project | Concentrating Solar Power | NREL 100MW Molten Salt Tower CSP project Status Date Turbine Capacity: Net: 100.0 MW Gross: 100.0 MW Status: Under development Do you have more information , corrections, or comments? Background Technology: Power tower Status: Under development Country: China City

Maximum on the Electrical Conductivity Polytherm of Molten TeCl4

NASA Astrophysics Data System (ADS)

Salyulev, Alexander B.; Potapov, Alexei M.

2017-05-01

The electrical conductivity of molten TeCl4 was measured up to 761K, i.e. 106 degrees above the normal boiling point of the salt. For the first time it was found that TeCl4 electrical conductivity polytherm has a maximum. It was recorded at 705K (κmax=0.245 Sm/cm), whereupon the conductivity decreases as the temperature rises. The activation energy of electrical conductivity was calculated.

Mesocarbon microbead based graphite for spherical fuel element to inhibit the infiltration of liquid fluoride salt in molten salt reactor

NASA Astrophysics Data System (ADS)

Zhong, Yajuan; Zhang, Junpeng; Lin, Jun; Xu, Liujun; Zhang, Feng; Xu, Hongxia; Chen, Yu; Jiang, Haitao; Li, Ziwei; Zhu, Zhiyong; Guo, Quangui

2017-07-01

Mesocarbon microbeads (MCMB) and quasi-isostatic pressing method were used to prepare MCMB based graphite (MG) for spherical fuel element to inhibit the infiltration of liquid fluoride salt in molten salt reactor (MSR). Characteristics of mercury infiltration and molten salt infiltration in MG were investigated and compared with A3-3 (graphite for spherical fuel element in high temperature gas cooled reactor) to identify the infiltration behaviors. The results indicated that MG had a low porosity about 14%, and an average pore diameter of 96 nm. Fluoride salt occupation of A3-3 (average pore diameter was 760 nm) was 10 wt% under 6.5 atm, whereas salt gain did not infiltrate in MG even up to 6.5 atm. It demonstrated that MG could inhibit the infiltration of liquid fluoride salt effectively. Coefficient of thermal expansion (CTE) of MG lies in 6.01 × 10-6 K-1 (α∥) and 6.15 × 10-6 K-1 (α⊥) at the temperature range of 25-700 °C. The anisotropy factor of MG calculated by CTE maintained below 1.02, which could meet the requirement of the spherical fuel element (below 1.30). The constant isotropic property of MG is beneficial for the integrity and safety of the graphite used in the spherical fuel element for a MSR.

Conceptual Design of a 100 MWe Modular Molten Salt Power Tower Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

James E. Pacheco; Carter Moursund, Dale Rogers, David Wasyluk

2011-09-20

A conceptual design of a 100 MWe modular molten salt solar power tower plant has been developed which can provide capacity factors in the range of 35 to 75%. Compared to single tower plants, the modular design provides a higher degree of flexibility in achieving the desired customer's capacity factor and is obtained simply by adjusting the number of standard modules. Each module consists of a standard size heliostat field and receiver system, hence reengineering and associated unacceptable performance uncertainties due to scaling are eliminated. The modular approach with multiple towers also improves plant availability. Heliostat field components, receivers andmore » towers are shop assembled allowing for high quality and minimal field assembly. A centralized thermal-storage system stores hot salt from the receivers, allowing nearly continuous power production, independent of solar energy collection, and improved parity with the grid. A molten salt steam generator converts the stored thermal energy into steam, which powers a steam turbine generator to produce electricity. This paper describes the conceptual design of the plant, the advantages of modularity, expected performance, pathways to cost reductions, and environmental impact.« less

A novel rechargeable zinc-air battery with molten salt electrolyte

NASA Astrophysics Data System (ADS)

Liu, Shuzhi; Han, Wei; Cui, Baochen; Liu, Xianjun; Zhao, Fulin; Stuart, Jessica; Licht, Stuart

2017-02-01

Zinc-air batteries have been proposed for EV applications and large-scale electricity storage such as wind and solar power. Although zinc-air batteries are very promising, there are numerous technological barriers to overcome. We demonstrate for the first time, a new rechargeable zinc-air battery that utilizes a molten Li0.87Na0.63K0.50CO3 eutectic electrolyte with added NaOH. Cyclic voltammetry reveals that a reversible deposition/dissolution of zinc occurs in the molten Li0.87Na0.63K0.50CO3 eutectic. At 550 °C, this zinc-air battery performs with a coulombic efficiency of 96.9% over 110 cycles, having an average charging potential of ∼1.43 V and discharge potential of ∼1.04 V. The zinc-air battery uses cost effective steel and nickel electrodes without the need for any precious metal catalysts. Moreover, the molten salt electrolyte offers advantages over aqueous electrolytes, avoiding the common aqueous alkaline electrolyte issues of hydrogen evolution, Zn dendrite formation, "drying out", and carbonate precipitation.

Spin-injection optical pumping of molten cesium salt and its NMR diagnosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishikawa, Kiyoshi

2015-07-15

Nuclear spin polarization of cesium ions in the salt was enhanced during optical pumping of cesium vapor at high magnetic field. Significant motional narrowing and frequency shift of NMR signals were observed by intense laser heating of the salt. When the hyperpolarized salt was cooled by blocking the heating laser, the signal width and frequency changed during cooling and presented the phase transition from liquid to solid. Hence, we find that the signal enhancement is mostly due to the molten salt and nuclear spin polarization is injected into the salt efficiently in the liquid phase. We also show that opticalmore » pumping similarly induces line narrowing in the solid phase. The use of powdered salt provided an increase in effective surface area and signal amplitude without glass wool in the glass cells.« less

Measuring lanthanide concentrations in molten salt using laser-induced breakdown spectroscopy (LIBS).

PubMed

Weisberg, Arel; Lakis, Rollin E; Simpson, Michael F; Horowitz, Leo; Craparo, Joseph

2014-01-01

The versatility of laser-induced breakdown spectroscopy (LIBS) as an analytical method for high-temperature applications was demonstrated through measurement of the concentrations of the lanthanide elements europium (Eu) and praseodymium (Pr) in molten eutectic lithium chloride-potassium chloride (LiCl-KCl) salts at a temperature of 500 °C. Laser pulses (1064 nm, 7 ns, 120 mJ/pulse) were focused on the top surface of the molten salt samples in a laboratory furnace under an argon atmosphere, and the resulting LIBS signals were collected using a broadband Echelle-type spectrometer. Partial least squares (PLS) regression using leave-one-sample-out cross-validation was used to quantify the concentrations of Eu and Pr in the samples. The root mean square error of prediction (RMSEP) for Eu was 0.13% (absolute) over a concentration range of 0-3.01%, and for Pr was 0.13% (absolute) over a concentration range of 0-1.04%.

Synthesis and Thermodynamic Stability of Ba2B‧B″O6 and Ba3B*B″2O9 Perovskites Using the Molten Salt Method

NASA Astrophysics Data System (ADS)

Meng, Wei; Virkar, Anil V.

1999-12-01

A number of mixed perovskites of the types Ba2B‧B″O6 (BaB‧1/2B″1/2O3) and Ba3B*B″2O9 (BaB*1/3B″2/3O3) where B‧=Gd, La, Nd, Sm, or Y; B″=Nb and B*=Ca were synthesized by a conventional calcination process, as well as by the molten salt method. The former consists of calcining appropriate mixtures of oxide or carbonate precursors in air at elevated temperatures (∼1250°C). The latter method consists of adding appropriate mixtures of oxide or carbonate precursors to a molten salt bath at relatively low temperatures (on the order of 300 to 500°C) so that the requisite compound is formed by dissolution-reprecipitation. X-ray diffraction confirmed the formation of a single-phase perovskite in each case with calcination at 1250°C. In a molten salt bath, however, all except Ba2LaNbO6 and Ba2NdNbO6 formed the perovskite structure. On the contrary, powders of Ba2LaNbO6 and Ba2NdNbO6 formed by a high-temperature calcination process readily decomposed when introduced into the molten salt bath. The formation of the requisite perovskite at a temperature as low as 350°C in a molten salt suggests that: (a) The perovskite is stable at 350°C. (b) The molten salt exhibits sufficient precursor solubility for the dissolution-reprecipitation process to occur in a reasonable time. Similarly, the decomposition of Ba2LaNbO6 and Ba2NdNbO6 in a molten salt bath shows that these materials are thermodynamically unstable at the temperature of the molten salt bath.

In situ production of titanium dioxide nanoparticles in molten salt phase for thermal energy storage and heat-transfer fluid applications

NASA Astrophysics Data System (ADS)

Lasfargues, Mathieu; Bell, Andrew; Ding, Yulong

2016-06-01

In this study, TiO2 nanoparticles (average particle size 16 nm) were successfully produced in molten salt phase and were showed to significantly enhance the specific heat capacity of a binary eutectic mixture of sodium and potassium nitrate (60/40) by 5.4 % at 390 °C and 7.5 % at 445 °C for 3.0 wt% of precursors used. The objective of this research was to develop a cost-effective alternate method of production which is potentially scalable, as current techniques utilized are not economically viable for large quantities. Enhancing the specific heat capacity of molten salt would promote more competitive pricing for electricity production by concentrating solar power plant. Here, a simple precursor (TiOSO4) was added to a binary eutectic mixture of potassium and sodium nitrate, heated to 450 °C, and cooled to witness the production of nanoparticles.

Modelisation of the SECMin molten salts environment

NASA Astrophysics Data System (ADS)

Lucas, M.; Slim, C.; Delpech, S.; di Caprio, D.; Stafiej, J.

2014-06-01

We develop a cellular automata modelisation of SECM experiments to study corrosion in molten salt media for generation IV nuclear reactors. The electrodes used in these experiments are cylindrical glass tips with a coaxial metal wire inside. As the result of simulations we obtain the current approach curves of the electrodes with geometries characterized by several values of the ratios of glass to metal area at the tip. We compare these results with predictions of the known analytic expressions, solutions of partial differential equations for flat uniform geometry of the substrate. We present the results for other, more complicated substrate surface geometries e. g. regular saw modulated surface, surface obtained by Eden model process, ...

Molten salt thermal energy storage for utility peaking loads

NASA Technical Reports Server (NTRS)

Ferrara, A.; Haslett, R.; Joyce, J.

1977-01-01

This paper considers the use of thermal energy storage (TES) in molten salts to increase the capacity of power plants. Five existing fossil and nuclear electric utility plants were selected as representative of current technology. A review of system load diagrams indicated that TES to meet loads over 95% of peak was a reasonable goal. Alternate TES heat exchanger locations were evaluated, showing that the stored energy should be used either for feedwater heating or to generate steam for an auxiliary power cycle. Specific salts for each concept are recommended. Design layouts were prepared for one plant, and it was shown that a TES tube/shell heat exchanger system could provide about 7% peaking capability at lower cost than adding steam generation capacity. Promising alternate heat exchanger concepts were also identified.

Computational Analysis of Nanoparticles-Molten Salt Thermal Energy Storage for Concentrated Solar Power Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Vinod

2017-05-05

High fidelity computational models of thermocline-based thermal energy storage (TES) were developed. The research goal was to advance the understanding of a single tank nanofludized molten salt based thermocline TES system under various concentration and sizes of the particles suspension. Our objectives were to utilize sensible-heat that operates with least irreversibility by using nanoscale physics. This was achieved by performing computational analysis of several storage designs, analyzing storage efficiency and estimating cost effectiveness for the TES systems under a concentrating solar power (CSP) scheme using molten salt as the storage medium. Since TES is one of the most costly butmore » important components of a CSP plant, an efficient TES system has potential to make the electricity generated from solar technologies cost competitive with conventional sources of electricity.« less

Separation behaviors of actinides from rare-earths in molten salt electrorefining using saturated liquid cadmium cathode

NASA Astrophysics Data System (ADS)

Kato, Tetsuya; Inoue, Tadashi; Iwai, Takashi; Arai, Yasuo

2006-10-01

Electrorefining in the molten LiCl-KCl eutectic salt containing actinide (An) and rare-earth (RE) elements was conducted to recover An elements up to 10 wt% into liquid cadmium (Cd) cathode, which is much higher than the solubility of the An elements in liquid Cd at the experimental temperature of 773 K. In the saturated Cd cathode, the An and RE elements were recovered forming a PuCd 11 type compound, MCd 11 (M = An and RE elements). The separation factors of element M against Pu defined as [M/Pu in Cd alloy (cathode)]/[M/Pu in molten salt] were calculated for the saturated Cd cathode including MCd 11. The separation factors were 0.011, 0.044, 0.064, and 0.064 for La, Ce, Pr, and Nd, respectively. These values were a little differed from 0.014, 0.038, 0.044, and 0.043 for the equilibrium unsaturated liquid Cd, respectively. The above slight differences were considered to be caused by the solid phase formation in the saturated Cd cathode and the electrochemical transfer of the An and RE elements in the molten salt.

Nitrogen-functionalization biochars derived from wheat straws via molten salt synthesis: An efficient adsorbent for atrazine removal.

PubMed

Yang, Fan; Sun, Lili; Xie, Weiling; Jiang, Qun; Gao, Yan; Zhang, Wei; Zhang, Ying

2017-12-31

N-doped porous carbon sheets (NPCS) resulted from wheat straws are fabricated through using molten salts via the carbonization-functionalization progress, which show unique hierarchical structure, large pore volume and high surface area with affluent micropores. Results indicate that there exist many hierarchical pores consisting of the single carbon sheet with ultrathin nature, owing to the template role of molten salt mixtures at high temperature. Such superior structure can bring about desired performance of adsorption capacity of 82.8mg/g and quick adsorption rate of 1.43L/(gh) with an initial concentration of 35mg/L at 25°C. Langmuir and Freundlich models are adopted to interpret the adsorption behavior of atrazine and modified Freundlich and intraparticle diffusion (IPD) models are employed to characterize the dynamics of adsorption. Furthermore, nitrogen-functionalization biochars via molten salt synthesis should be further developed as a one-pot methodology to produce N-doped carbons, opening up a feasible approach for resource utilization of crop straws and other biomass wastes. Copyright © 2017 Elsevier B.V. All rights reserved.

Molten Salt Power Tower Cost Model for the System Advisor Model (SAM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turchi, C. S.; Heath, G. A.

2013-02-01

This report describes a component-based cost model developed for molten-salt power tower solar power plants. The cost model was developed by the National Renewable Energy Laboratory (NREL), using data from several prior studies, including a contracted analysis from WorleyParsons Group, which is included herein as an Appendix. The WorleyParsons' analysis also estimated material composition and mass for the plant to facilitate a life cycle analysis of the molten salt power tower technology. Details of the life cycle assessment have been published elsewhere. The cost model provides a reference plant that interfaces with NREL's System Advisor Model or SAM. The referencemore » plant assumes a nominal 100-MWe (net) power tower running with a nitrate salt heat transfer fluid (HTF). Thermal energy storage is provided by direct storage of the HTF in a two-tank system. The design assumes dry-cooling. The model includes a spreadsheet that interfaces with SAM via the Excel Exchange option in SAM. The spreadsheet allows users to estimate the costs of different-size plants and to take into account changes in commodity prices. This report and the accompanying Excel spreadsheet can be downloaded at https://sam.nrel.gov/cost.« less

Advances toward industrialization of novel molten salt electrochemical processes.

PubMed

Ito, Yasuhiko; Nishikiori, Tokujiro; Tsujimura, Hiroyuki

2016-08-15

We have invented various novel molten salt electrochemical processes, that can be put to practical use in the fields of energy and materials. These processes are promising from both technological and commercial viewpoints, and they are currently under development for industrial application. To showcase current developments in work toward industrialization, we focus here on three of these processes: (1) electrolytic synthesis of ammonia from water and nitrogen under atmospheric pressure, (2) electrochemical formation of carbon film, and (3) plasma-induced discharge electrolysis to produce nanoparticles.

Solid oxide membrane-assisted controllable electrolytic fabrication of metal carbides in molten salt.

PubMed

Zou, Xingli; Zheng, Kai; Lu, Xionggang; Xu, Qian; Zhou, Zhongfu

2016-08-15

Silicon carbide (SiC), titanium carbide (TiC), zirconium carbide (ZrC), and tantalum carbide (TaC) have been electrochemically produced directly from their corresponding stoichiometric metal oxides/carbon (MOx/C) precursors by electrodeoxidation in molten calcium chloride (CaCl2). An assembled yttria stabilized zirconia solid oxide membrane (SOM)-based anode was employed to control the electrodeoxidation process. The SOM-assisted controllable electrochemical process was carried out in molten CaCl2 at 1000 °C with a potential of 3.5 to 4.0 V. The reaction mechanism of the electrochemical production process and the characteristics of these produced metal carbides (MCs) were systematically investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses clearly identify that SiC, TiC, ZrC, and TaC carbides can be facilely fabricated. SiC carbide can be controlled to form a homogeneous nanowire structure, while the morphologies of TiC, ZrC, and TaC carbides exhibit porous nodular structures with micro/nanoscale particles. The complex chemical/electrochemical reaction processes including the compounding, electrodeoxidation, dissolution-electrodeposition, and in situ carbonization processes in molten CaCl2 are also discussed. The present results preliminarily demonstrate that the molten salt-based SOM-assisted electrodeoxidation process has the potential to be used for the facile and controllable electrodeoxidation of MOx/C precursors to micro/nanostructured MCs, which can potentially be used for various applications.

Electrochemical Carbonitriding of 316L Stainless Steel in Molten Salt System

NASA Astrophysics Data System (ADS)

Ren, Yanjie; Xiao, Bo; Chen, Yaqing; Chen, Jian; Chen, Jianlin

This paper reports an electrochemical route for carbonitriding 316L stainless steel in molten salts. Carbonitriding process was accomplished in molten alkaline chloride (LiCl/KCl) with the addition of KNO2 at 480∘C using a three-electrode system in which a carbon sheet was the counter electrode. The carbonitriding layer of 316L stainless steel obtained by potentiostatic electrolysis was analyzed by several physical techniques. The results showed that a compact layer with a thickness of about 7μm formed after the treatment. According to X-ray diffraction analysis, chromium nitride and carbide formed on the surface of carbonitriding layer. The microhardness of the carbonitriding layer is HV 336, as compared to HV 265 for the substrate.

Transmutation Scoping Studies for a Chloride Molten Salt Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heidet, Florent; Feng, Bo; Kim, Taek

2016-01-01

Over the past few years, there has been strong renewed interest from private industry, mostly from start-up enterprises, in molten salt reactor (MSR) technologies because of the unique properties of this class of reactors. These are reactors in which the fuel is homogeneously mixed with the coolant in the form of liquid salts and is circulated continuously into and out of the active core region with on-line fuel management, salt treatment, and salt processing. In response to such wide-spread interest, Argonne National Laboratory is expanding its well-established reactor modelling and simulation expertise and infrastructure to enable detailed analysis and designmore » of MSRs. The tools being developed are able to simulate the continuous fuel flow, the complex on-line fuel management and elemental removal processes (e.g., fission product removal) using depletion steps representative of a real MSR system. Leveraging these capabilities, a parametric study on the transmutation performance of a simplified actinide-burning MSR concept that uses a chloride-based salt was performed. This type of salt has attracted attention over the more commonly discussed fluoride-based salts since no tritium is produced as a result of irradiation and it is compatible with a fast neutron spectrum. The studies discussed in this paper examine the performance of a burner MSR design with a fixed core size and power density over a range of possible fuel salt molar ratios with NaCl-MgCl2 as the carrier salt. The intent is to quantify the impact on the required transuranics content of the make-up fuel, the actinide transmutation rates, and other performance characteristics for typical burner MSR designs.« less

In situ production of titanium dioxide nanoparticles in molten salt phase for thermal energy storage and heat-transfer fluid applications.

PubMed

Lasfargues, Mathieu; Bell, Andrew; Ding, Yulong

In this study, TiO 2 nanoparticles (average particle size 16 nm) were successfully produced in molten salt phase and were showed to significantly enhance the specific heat capacity of a binary eutectic mixture of sodium and potassium nitrate (60/40) by 5.4 % at 390 °C and 7.5 % at 445 °C for 3.0 wt% of precursors used. The objective of this research was to develop a cost-effective alternate method of production which is potentially scalable, as current techniques utilized are not economically viable for large quantities. Enhancing the specific heat capacity of molten salt would promote more competitive pricing for electricity production by concentrating solar power plant. Here, a simple precursor (TiOSO 4 ) was added to a binary eutectic mixture of potassium and sodium nitrate, heated to 450 °C, and cooled to witness the production of nanoparticles.

Formation of Intermetallic Phases in Al-Sc Alloys Prepared by Molten Salt Electrolysis at Elevated Temperatures

NASA Astrophysics Data System (ADS)

Wang, Zengjie; Guan, Chunyang; Liu, Qiaochu; Xue, Jilai

Molten salts electrolysis method to prepare Al-RE alloys has attracted increasing attention recently. CaCl2 and Na3AlF6 were the most often used melts for this purpose. In this work, Al-Sc alloys prepared by electrolytic deposition process in both CaCl2 and Na3AlF6 melts were investigated, respectively. It was found that Sc distributes almost uniformly and Sc contents increase with increasing current intensity in both melts. Current efficiency was measured for comparison among various current densities applied. The alloy products were analyzed using XRD and SEM, where the formation behaviors of Al-Sc intermetallics were investigated in details. The experimental and theoretical results demonstrate that Al3Sc and Al0.968Sc0.032 are the major precipitates in the Al-Sc alloys prepared by molten electrolysis. The results are useful for selection and optimization of the molten salts compositions and the parameters of electrolysis operation.

Laser-Induced Breakdown Spectroscopy (LIBS) Measurement of Uranium in Molten Salt.

PubMed

Williams, Ammon; Phongikaroon, Supathorn

2018-01-01

In this current study, the molten salt aerosol-laser-induced breakdown spectroscopy (LIBS) system was used to measure the uranium (U) content in a ternary UCl 3 -LiCl-KCl salt to investigate and assess a near real-time analytical approach for material safeguards and accountability. Experiments were conducted using five different U concentrations to determine the analytical figures of merit for the system with respect to U. In the analysis, three U lines were used to develop univariate calibration curves at the 367.01 nm, 385.96 nm, and 387.10 nm lines. The 367.01 nm line had the lowest limit of detection (LOD) of 0.065 wt% U. The 385.96 nm line had the best root mean square error of cross-validation (RMSECV) of 0.20 wt% U. In addition to the univariate calibration approach, a multivariate partial least squares (PLS) model was developed to further analyze the data. Using partial least squares (PLS) modeling, an RMSECV of 0.085 wt% U was determined. The RMSECV from the multivariate approach was significantly better than the univariate case and the PLS model is recommended for future LIBS analysis. Overall, the aerosol-LIBS system performed well in monitoring the U concentration and it is expected that the system could be used to quantitatively determine the U compositions within the normal operational concentrations of U in pyroprocessing molten salts.

The mechanics of pressed-pellet separators in molten salt batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Kevin Nicholas; Roberts, Christine Cardinal; Roberts, Scott Alan

2014-06-01

We present a phenomenological constitutive model that describes the macroscopic behavior of pressed-pellet materials used in molten salt batteries. Such materials include separators, cathodes, and anodes. The purpose of this model is to describe the inelastic deformation associated with the melting of a key constituent, the electrolyte. At room temperature, all constituents of these materials are solid and do not transport cations so that the battery is inert. As the battery is heated, the electrolyte, a constituent typically present in the separator and cathode, melts and conducts charge by flowing through the solid skeletons of the anode, cathode, and separator.more » The electrochemical circuit is closed in this hot state of the battery. The focus of this report is on the thermal-mechanical behavior of the separator, which typically exhibits the most deformation of the three pellets during the process of activating a molten salt battery. Separator materials are composed of a compressed mixture of a powdered electrolyte, an inert binder phase, and void space. When the electrolyte melts, macroscopically one observes both a change in volume and shape of the separator that depends on the applied boundary conditions during the melt transition. Although porous flow plays a critical role in the battery mechanics and electrochemistry, the focus of this report is on separator behavior under flow-free conditions in which the total mass of electrolyte is static within the pellet. Specific poromechanics effects such as capillary pressure, pressure-saturation, and electrolyte transport between layers are not considered. Instead, a phenomenological model is presented to describe all such behaviors including the melting transition of the electrolyte, loss of void space, and isochoric plasticity associated with the binder phase rearrangement. The model is appropriate for use finite element analysis under finite deformation and finite temperature change conditions. The model

Specific heat capacity of molten salt-based alumina nanofluid.

PubMed

Lu, Ming-Chang; Huang, Chien-Hsun

2013-06-21

There is no consensus on the effect of nanoparticle (NP) addition on the specific heat capacity (SHC) of fluids. In addition, the predictions from the existing model have a large discrepancy from the measured SHCs in nanofluids. We show that the SHC of the molten salt-based alumina nanofluid decreases with reducing particle size and increasing particle concentration. The NP size-dependent SHC is resulted from an augmentation of the nanolayer effect as particle size reduces. A model considering the nanolayer effect which supports the experimental results was proposed.

Specific heat capacity of molten salt-based alumina nanofluid

PubMed Central

2013-01-01

There is no consensus on the effect of nanoparticle (NP) addition on the specific heat capacity (SHC) of fluids. In addition, the predictions from the existing model have a large discrepancy from the measured SHCs in nanofluids. We show that the SHC of the molten salt-based alumina nanofluid decreases with reducing particle size and increasing particle concentration. The NP size-dependent SHC is resulted from an augmentation of the nanolayer effect as particle size reduces. A model considering the nanolayer effect which supports the experimental results was proposed. PMID:23800321

Hot corrosion behavior of magnesia-stabilized ceramic material in a lithium molten salt

NASA Astrophysics Data System (ADS)

Cho, Soo-Haeng; Kim, Sung-Wook; Kim, Dae-Young; Lee, Jong-Hyeon; Hur, Jin-Mok

2017-07-01

The isothermal and cyclic corrosion behaviors of magnesia-stabilized zirconia in a LiCl-Li2O molten salt were investigated at 650 °C in an argon atmosphere. The weights of as-received and corroded specimens were measured and the microstructures, morphologies, and chemical compositions were analyzed by scanning electron microscopy, X-ray energy dispersive spectroscopy, and X-ray diffraction. For processes where Li is formed at the cathode during electrolysis, the corrosion rate was about five times higher than those of isothermal and thermal cycling processes. During isothermal tests, the corrosion product Li2ZrO3 was formed after 216 h. During thermal cycling, Li2ZrO3 was not detected until after the completion of 14 cycles. There was no evidence of cracks, pores, or spallation on the corroded surfaces, except when Li was formed. We demonstrate that magnesia-stabilized zirconia is beneficial for increasing the hot corrosion resistance of structural materials subjected to high temperature molten salts containing Li2O.

Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

DOEpatents

Cassano, Anthony A.

1985-01-01

A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs.

Preliminary study on weapon grade uranium utilization in molten salt reactor miniFUJI

NASA Astrophysics Data System (ADS)

Aji, Indarta Kuncoro; Waris, A.

2014-09-01

Preliminary study on weapon grade uranium utilization in 25MWth and 50MWth of miniFUJI MSR (molten salt reactor) has been carried out. In this study, a very high enriched uranium that we called weapon grade uranium has been employed in UF4 composition. The 235U enrichment is 90 - 95 %. The results show that the 25MWth miniFUJI MSR can get its criticality condition for 1.56 %, 1.76%, and 1.96% of UF4 with 235U enrichment of at least 93%, 90%, and 90%, respectively. In contrast, the 50 MWth miniFUJI reactor can be critical for 1.96% of UF4 with 235U enrichment of at smallest amount 95%. The neutron spectra are almost similar for each power output.

Low-Temperature Molten-Salt Production of Silicon Nanowires by the Electrochemical Reduction of CaSiO3.

PubMed

Dong, Yifan; Slade, Tyler; Stolt, Matthew J; Li, Linsen; Girard, Steven N; Mai, Liqiang; Jin, Song

2017-11-13

Silicon is an extremely important technological material, but its current industrial production by the carbothermic reduction of SiO 2 is energy intensive and generates CO 2 emissions. Herein, we developed a more sustainable method to produce silicon nanowires (Si NWs) in bulk quantities through the direct electrochemical reduction of CaSiO 3 , an abundant and inexpensive Si source soluble in molten salts, at a low temperature of 650 °C by using low-melting-point ternary molten salts CaCl 2 -MgCl 2 -NaCl, which still retains high CaSiO 3 solubility, and a supporting electrolyte of CaO, which facilitates the transport of O 2- anions, drastically improves the reaction kinetics, and enables the electrolysis at low temperatures. The Si nanowire product can be used as high-capacity Li-ion battery anode materials with excellent cycling performance. This environmentally friendly strategy for the practical production of Si at lower temperatures can be applied to other molten salt systems and is also promising for waste glass and coal ash recycling. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Status Report on Scoping Reactor Physics and Sensitivity/Uncertainty Analysis of LR-0 Reactor Molten Salt Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Nicholas R.; Mueller, Donald E.; Patton, Bruce W.

2016-08-31

Experiments are being planned at Research Centre Rež (RC Rež) to use the FLiBe (2 7LiF-BeF 2) salt from the Molten Salt Reactor Experiment (MSRE) to perform reactor physics measurements in the LR-0 low power nuclear reactor. These experiments are intended to inform on neutron spectral effects and nuclear data uncertainties for advanced reactor systems utilizing FLiBe salt in a thermal neutron energy spectrum. Oak Ridge National Laboratory (ORNL) is performing sensitivity/uncertainty (S/U) analysis of these planned experiments as part of the ongoing collaboration between the United States and the Czech Republic on civilian nuclear energy research and development. Themore » objective of these analyses is to produce the sensitivity of neutron multiplication to cross section data on an energy-dependent basis for specific nuclides. This report provides a status update on the S/U analyses of critical experiments at the LR-0 Reactor relevant to fluoride salt-cooled high temperature reactor (FHR) and liquid-fueled molten salt reactor (MSR) concepts. The S/U analyses will be used to inform design of FLiBe-based experiments using the salt from MSRE.« less

On-line Monitoring of Actinide Concentrations in Molten Salt Electrolyte

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtis W. Johnson; Mary Lou Dunzik-Gougar; Shelly X. Li

2006-11-01

Pyroprocessing, a treatment method for spent nuclear fuel (SNF), is currently being studied at the Idaho National Laboratory. The key operation of pyroprocessing which takes place in an electrorefiner is the electrochemical separation of actinides from other constituents in spent fuel. Efficient operation of the electrorefiner requires online monitoring of actinide concentrations in the molten salt electrolyte. Square-wave voltammetry (SWV) and normal pulse voltammetry (NPV) are being investigated to assess their applicability to the measurement of actinide concentrations in the electrorefiner.

Transmutation and activation of reduced activation ferritic martensitic steel in molten salt cooled fusion power plants

NASA Astrophysics Data System (ADS)

Cheng, E. T.

2004-08-01

Neutron activation analysis was conducted for the reduced activation ferritic/martensitic (RAFM) steel used in flibe molten-salt cooled fusion blankets. After 22.4 MW yr/m 2 of neutron exposure, the RAFM steel first wall in a molten salt blanket with 40% lithium-6 enrichment in lithium was found to be within 1 mSv/h in contact dose rate after 100 yr of cooling. The contact dose rate drops to 30 and 20 μSv/h or less, respectively, when the cooling times are 300 and 500 yr after discharge. The RAFM steel discharged from the high-temperature shield component would be allowed for hands-on recycling after 100 yr of cooling, when the contact dose rate is 10 μSv/h or less. The most significant changes found in the RAFM steel first wall due to nuclear transmutation, are 10% decrease in W and 10% increase in Ti. Additionally, there are minor elements produced: Mn - <1.2%, V - <0.26%, Re - <0.2%, Ta - <0.08%, and Os - <0.1%, all in weight percent. The gaseous elements generated are H and He, and the, respectively, accumulated quantities are about 260 and 190 wppm.

Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

DOEpatents

Cassano, A.A.

1985-07-02

A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs. 3 figs.

Direct oxygen removal technique for recycling titanium using molten MgCl2 salt.

PubMed

Okabe, Toru H; Hamanaka, Yuki; Taninouchi, Yu-Ki

2016-08-15

Deoxidation of Ti, or direct removal of O dissolved in metallic Ti, is known to be extremely difficult when Mg is used as the deoxidizing agent. This difficulty arises because the chemical potential of O2, pO2, under Mg/MgO equilibrium is high (approximately 10(-41) atm at 1200 K) and is equivalent to that of Ti containing ∼2 mass% O at 1200 K. Therefore, when deoxidizing Ti to the commercial level of high-grade pure Ti (below 0.05 mass% O) using an Mg reductant at 1200 K, the activity of the reaction product MgO (aMgO) must be decreased to below ∼0.025, which is difficult in practice. In this study, the removal of O in Ti in molten MgCl2 salt using an electrochemical technique was examined at ∼1173 K with the objective of obtaining Ti containing less than 0.05 mass% O. Ti samples and graphite electrodes immersed in molten MgCl2 served as the cathode and anode, respectively. A constant voltage was applied between the electrodes using an external DC source. Molten MgCl2 was employed to produce the deoxidizing agent Mg and to facilitate deoxidation of Ti by decreasing the activity of the reaction product MgO. By applying a voltage of approximately 3.1 V between the electrodes, the chemical potential of Mg in the molten MgCl2 was increased at the surface of the Ti cathode, and the Ti samples were deoxidized. The resulting O species, mainly formed O(2-) dissolved in the molten MgCl2, was removed from the molten salt by reacting with the C anode to form CO (or CO2) gas. Ti wires containing 0.12 mass% O were deoxidized to less than 0.02 mass% O. In some cases, the O concentration in the Ti samples was reduced to the level of 0.01 mass%, which cannot be accomplished using the conventional Kroll process. The possible application of this deoxidation technique to practical industrial recycling processes is discussed.

Determination and evaluation of the thermophysical properties of an alkali carbonate eutectic molten salt.

PubMed

An, Xuehui; Cheng, Jinhui; Zhang, Peng; Tang, Zhongfeng; Wang, Jianqiang

2016-08-15

The thermal physical properties of Li2CO3-Na2CO3-K2CO3 eutectic molten salt were comprehensively investigated. It was found that the liquid salt can remain stable up to 658 °C (the onset temperature of decomposition) by thermal analysis, and so the investigations on its thermal physical parameters were undertaken from room temperature to 658 °C. The density was determined using a self-developed device, with an uncertainty of ±0.00712 g cm(-3). A cooling curve was obtained from the instrument, giving the liquidus temperature. For the first time, we report the obtainment of the thermal diffusivity using a laser flash method based on a special crucible design and establishment of a specific sample preparation method. Furthermore, the specific heat capacity was also obtained by use of DSC, and combined with thermal diffusivity and density, was used to calculate the thermal conductivity. We additionally built a rotating viscometer with high precision in order to determine the molten salt viscosity. All of these parameters play an important part in the energy storage and transfer calculation and safety evaluation for a system.

The Corrosion Behavior of Stainless Steel 316L in Novel Quaternary Eutectic Molten Salt System

NASA Astrophysics Data System (ADS)

Wang, Tao; Mantha, Divakar; Reddy, Ramana G.

2017-03-01

In this article, the corrosion behavior of stainless steel 316L in a low melting point novel LiNO3-NaNO3-KNO3-NaNO2 eutectic salt mixture was investigated at 695 K which is considered as thermally stable temperature using electrochemical and isothermal dipping methods. The passive region in the anodic polarization curve indicates the formation of protective oxides layer on the sample surface. After isothermal dipping corrosion experiments, samples were analyzed using SEM and XRD to determine the topography, corrosion products, and scale growth mechanisms. It was found that after long-term immersion in the LiNO3-NaNO3-KNO3-NaNO2 molten salt, LiFeO2, LiFe5O8, Fe3O4, (Fe, Cr)3O4 and (Fe, Ni)3O4 oxides were formed. Among these corrosion products, LiFeO2 formed a dense and protective layer which prevents the SS 316L from severe corrosion.

Study on Utilization of Super Grade Plutonium in Molten Salt Reactor FUJI-U3 using CITATION Code

NASA Astrophysics Data System (ADS)

Wulandari, Cici; Waris, Abdul; Pramuditya, Syeilendra; Asril, Pramutadi AM; Novitrian

2017-07-01

FUJI-U3 type of Molten Salt Reactor (MSR) has a unique design since it consists of three core regions in order to avoid the replacement of graphite as moderator. MSR uses floride as a nuclear fuel salt with the most popular chemical composition is LiF-BeF2-ThF4-233UF4. ThF4 and 233UF4 are the fertile and fissile materials, respectively. On the other hand, LiF and BeF2 working as both fuel and heat transfer medium. In this study, the super grade plutonium will be utilized as substitution of 233U since plutonium is easier to be obtained compared to 233U as main fuel. Neutronics calculation was performed by using PIJ and CITATION modules of SRAC 2002 code with JENDL 3.2 as nuclear data library.

Electrochemical monitoring of high-temperature molten-salt corrosion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, G.; Stott, F.H.; Dawson, J.L.

1990-02-01

Hot molten-salt corrosion can cause serious metal degradation in boiler plant, incinerators, and furnaces. In this research, electrochemical-impedance and electrochemical-noise techniques have been evaluated for the monitoring of hot-corrosion processes in such plants. Tests have been carried out on Ni-1% Co and Alloy 800, a commercial material of interest to operators of industrial plants. Electrochemical-impedance and electrochemical-noise data were compared with the results of metallographic examination of the test alloys and showed reasonable correlation between the electrochemical data and the actual degradation processes. This preliminary work indicated that the electrochemical techniques show considerable promise as instruments for the monitoring ofmore » high-temperature corrosion processes.« less

Determination of thermal physical properties of alkali fluoride/carbonate eutectic molten salt

NASA Astrophysics Data System (ADS)

An, Xue-Hui; Cheng, Jin-Hui; Su, Tao; Zhang, Peng

2017-06-01

Molten salts used in high temperatures are more and more interested in the CSP for higher energy conversion efficiency. Thermal physical properties are the basic engineering data of thermal hydraulic calculation and safety analysis. Therefore, the thermophysical performances involving density, specific heat capacity, viscosity and thermal conductivity of FLiNaK, (LiNaK)2CO3 and LiF(NaK)2CO3 molten salts are experimentally determined and through comparison the general rules can be summarized. Density measurement was performed on the basis of Archimedes theory; specific heat capacity was measured using the DSC technique; viscosity was tested based on the rotating method; and the thermal conductivity was gained by laser flash method with combination of the density, specific heat capacity and thermal diffusivity through a formula. Finally, the energy storage capacity and figures of merit are calculated to evaluate their feasibility as TES and HFT media. The results show that FLiNaK has the largest energy storage capacity and best heat transfer performance, LiF(NaK)2CO3 is secondary, and (LiNaK)2CO3 has the smallest.

On purpose simulation model for molten salt CSP parabolic trough

NASA Astrophysics Data System (ADS)

Caranese, Carlo; Matino, Francesca; Maccari, Augusto

2017-06-01

The utilization of computer codes and simulation software is one of the fundamental aspects for the development of any kind of technology and, in particular, in CSP sector for researchers, energy institutions, EPC and others stakeholders. In that extent, several models for the simulation of CSP plant have been developed with different main objectives (dynamic simulation, productivity analysis, techno economic optimization, etc.), each of which has shown its own validity and suitability. Some of those models have been designed to study several plant configurations taking into account different CSP plant technologies (Parabolic trough, Linear Fresnel, Solar Tower or Dish) and different settings for the heat transfer fluid, the thermal storage systems and for the overall plant operating logic. Due to a lack of direct experience of Molten Salt Parabolic Trough (MSPT) commercial plant operation, most of the simulation tools do not foresee a suitable management of the thermal energy storage logic and of the solar field freeze protection system, but follow standard schemes. ASSALT, Ase Software for SALT csp plants, has been developed to improve MSPT plant's simulations, by exploiting the most correct operational strategies in order to provide more accurate technical and economical results. In particular, ASSALT applies MSPT specific control logics for the electric energy production and delivery strategy as well as the operation modes of the Solar Field in off-normal sunshine condition. With this approach, the estimated plant efficiency is increased and the electricity consumptions required for the plant operation and management is drastically reduced. Here we present a first comparative study on a real case 55 MWe Molten Salt Parabolic Trough CSP plant placed in the Tibetan highlands, using ASSALT and SAM (System Advisor Model), which is a commercially available simulation tool.

Process for recovering tritium from molten lithium metal

DOEpatents

Maroni, Victor A.

1976-01-01

Lithium tritide (LiT) is extracted from molten lithium metal that has been exposed to neutron irradiation for breeding tritium within a thermonuclear or fission reactor. The extraction is performed by intimately contacting the molten lithium metal with a molten lithium salt, for instance, lithium chloride - potassium chloride eutectic to distribute LiT between the salt and metal phases. The extracted tritium is recovered in gaseous form from the molten salt phase by a subsequent electrolytic or oxidation step.

Molten salt CO2 capture and electro-transformation (MSCC-ET) into capacitive carbon at medium temperature: effect of the electrolyte composition.

PubMed

Deng, Bowen; Chen, Zhigang; Gao, Muxing; Song, Yuqiao; Zheng, Kaiyuan; Tang, Juanjuan; Xiao, Wei; Mao, Xuhui; Wang, Dihua

2016-08-15

Electrochemical transformation of CO2 into functional materials or fuels (i.e., carbon, CO) in high temperature molten salts has been demonstrated as a promising way of carbon capture, utilisation and storage (CCUS) in recent years. In a view of continuous operation, the electrolysis process should match very well with the CO2 absorption kinetics. At the same time, in consideration of the energy efficiency, a molten salt electrochemical cell running at lower temperature is more beneficial to a process powered by the fluctuating renewable electricity from solar/wind farms. Ternary carbonates (Li : Na : K = 43.5 : 31.5 : 25.0) and binary chlorides (Li : K = 58.5 : 41.5), two typical kinds of eutectic melt with low melting points and a wide electrochemical potential window, could be the ideal supporting electrolyte for the molten salt CO2 capture and electro-transformation (MSCC-ET) process. In this work, the CO2 absorption behaviour in Li2O/CaO containing carbonates and chlorides were investigated on a home-made gas absorption testing system. The electrode processes as well as the morphology and properties of carbon obtained in different salts are compared to each other. It was found that the composition of molten salts significantly affects the absorption of CO2, electrode processes and performance of the product. Furthermore, the relationship between the absorption and electro-transformation kinetics are discussed based on the findings.

Preparation of Al-Si Master Alloy by Electrochemical Reduction of Fly Ash in Molten Salt

NASA Astrophysics Data System (ADS)

Liu, Aimin; Li, Liangxing; Xu, Junli; Shi, Zhongning; Hu, Xianwei; Gao, Bingliang; Wang, Zhaowen; Yu, Jiangyu; Chen, Gong

2014-05-01

An electrochemical method on preparation of Al-Si master alloy was investigated in fluoride-based molten salts of 47.7wt.%NaF-43.3wt.%AlF3-4wt.%CaF2 containing 5 wt.% fly ash at 1233 K. The cathodic products obtained by galvanostatic electrolysis were analyzed by means of x-ray diffraction, x-ray fluorescence, scanning electron microscopy, and energy-dispersive spectrometry. The result showed that the compositions of the products are Al, Si, and Al3.21Si0.47. Meanwhile, the cathodic electrochemical process was studied by cyclic voltammetry, and the results showed the reduction peak of aluminum deposition is at -1.3 V versus the platinum quasi-reference electrode in 50.3wt.%NaF-45.7wt.%AlF3-4wt.%CaF2 molten salts, while the reduction peak at -1.3 V was the co-deposition of aluminum and silicon when the fly ash was added. The silicon and iron were formed via both co-deposition and aluminothermic reduction. In the electrolysis experiments, current efficiency first increased to a maximum value of 40.7% at a current density of 0.29 A/cm2, and then it decreased with the increase of current density. With the electrolysis time lasting, the content of aluminum in the alloys decreased from 76.05 wt.% to 48.29 wt.% during 5 h, while the content of silicon increased from 15.94 wt.% to 37.89 wt.%.

Stress corrosion cracking of Ti-8Al-1 Mo-1V in molten salts

NASA Technical Reports Server (NTRS)

Smyrl, W. H.; Blackburn, M. J.

1975-01-01

The stress corrosion cracking (SCC) behavior of Ti-8Al-1 Mo-1V has been studied in several molten salt environments. Extensive data are reported for the alloy in highly pure LiCl-KCl. The influence of the metallurgical heat treatment and texture, and the mechanical microstructure show similarities with aqueous solutions at lower temperature. The fracture path and cracking modes are also similar to that found in other environments. The influence of H2O and H(-) in molten LiCl-KCl lead to the conclusion that hydrogen does not play a major role in crack extension in this environment.

Coupled optical and thermal detailed simulations for the accurate evaluation and performance improvement of molten salts solar towers

NASA Astrophysics Data System (ADS)

García-Barberena, Javier; Mutuberria, Amaia; Palacin, Luis G.; Sanz, Javier L.; Pereira, Daniel; Bernardos, Ana; Sanchez, Marcelino; Rocha, Alberto R.

2017-06-01

The National Renewable Energy Centre of Spain, CENER, and the Technology & Innovation area of ACS Cobra, as a result of their long term expertise in the CSP field, have developed a high-quality and high level of detail optical and thermal simulation software for the accurate evaluation of Molten Salts Solar Towers. The main purpose of this software is to make a step forward in the state-of-the-art of the Solar Towers simulation programs. Generally, these programs deal with the most critical systems of such plants, i.e. the solar field and the receiver, on an independent basis. Therefore, these programs typically neglect relevant aspects in the operation of the plant as heliostat aiming strategies, solar flux shapes onto the receiver, material physical and operational limitations, transient processes as preheating and secure cloud passing operating modes, and more. The modelling approach implemented in the developed program consists on effectively coupling detailed optical simulations of the heliostat field with also detailed and full-transient thermal simulations of the molten salts tube-based external receiver. The optical model is based on an accurate Monte Carlo ray-tracing method which solves the complete solar field by simulating each of the heliostats at once according to their specific layout in the field. In the thermal side, the tube-based cylindrical external receiver of a Molten Salts Solar Tower is modelled assuming one representative tube per panel, and implementing the specific connection layout of the panels as well as the internal receiver pipes. Each tube is longitudinally discretized and the transient energy and mass balances in the temperature dependent molten salts and steel tube models are solved. For this, a one dimensional radial heat transfer model based is used. The thermal model is completed with a detailed control and operation strategy module, able to represent the appropriate operation of the plant. An integration framework has been

An innovative spraying setup to obtain uniform salt(s) mixture deposition to investigate hot corrosion

NASA Astrophysics Data System (ADS)

Mannava, Venkateswararao; Swaminathan, A. Vignesh; Kamaraj, M.; Kottada, Ravi Sankar

2016-02-01

A hot corrosion study via molten salt deposition and its interaction with creep/fatigue play a critical role in predicting the life of gas turbine engine components. To do systematic hot corrosion studies, deposition of molten salts on specimens should be uniform with good adherence. Thus, the present study describes an in-house developed spraying setup that produces uniform and reliable molten salt deposition in a repeatable fashion. The efficacy of the present method was illustrated by depositing 90 wt. % Na2SO4 + 5 wt. % NaCl + 5 wt. % NaV O3 salt mixture on hot corrosion coupons and on creep specimens, and also by comparing with other deposition methods.

Potentiometric Sensor for Real-Time Remote Surveillance of Actinides in Molten Salts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Natalie J. Gese; Jan-Fong Jue; Brenda E. Serrano

2012-07-01

A potentiometric sensor is being developed at the Idaho National Laboratory for real-time remote surveillance of actinides during electrorefining of spent nuclear fuel. During electrorefining, fuel in metallic form is oxidized at the anode while refined uranium metal is reduced at the cathode in a high temperature electrochemical cell containing LiCl-KCl-UCl3 electrolyte. Actinides present in the fuel chemically react with UCl3 and form stable metal chlorides that accumulate in the electrolyte. This sensor will be used for process control and safeguarding of activities in the electrorefiner by monitoring the concentrations of actinides in the electrolyte. The work presented focuses onmore » developing a solid-state cation conducting ceramic sensor for detecting varying concentrations of trivalent actinide metal cations in eutectic LiCl-KCl molten salt. To understand the basic mechanisms for actinide sensor applications in molten salts, gadolinium was used as a surrogate for actinides. The ß?-Al2O3 was selected as the solid-state electrolyte for sensor fabrication based on cationic conductivity and other factors. In the present work Gd3+-ß?-Al2O3 was prepared by ion exchange reactions between trivalent Gd3+ from GdCl3 and K+-, Na+-, and Sr2+-ß?-Al2O3 precursors. Scanning electron microscopy (SEM) was used for characterization of Gd3+-ß?-Al2O3 samples. Microfocus X-ray Diffraction (µ-XRD) was used in conjunction with SEM energy dispersive X-ray spectroscopy (EDS) to identify phase content and elemental composition. The Gd3+-ß?-Al2O3 materials were tested for mechanical and chemical stability by exposing them to molten LiCl-KCl based salts. The effect of annealing on the exchanged material was studied to determine improvements in material integrity post ion exchange. The stability of the ß?-Al2O3 phase after annealing was verified by µ-XRD. Preliminary sensor tests with different assembly designs will also be presented.« less

High dispersibility and enhanced luminescence properties of BaMgAl10O17:Eu2+ phosphors derived from molten salt synthesis

NASA Astrophysics Data System (ADS)

Wang, Xiang; Li, Jin-hong; Shi, Ping-lu; Guan, Wei-min; Zhang, Hong-yao

2015-08-01

BaMgAl10O17:Eu2+ (BAM) phosphors were prepared via the molten salt synthesis (MSS) method. The NaCl-KCl eutectic mixture and LiF were used as the molten salt and flux, respectively. X-ray powder diffraction (XRD) patterns indicate that the BAM phase is formed above 1200 °C and that the addition of LiF leads to an obvious improvement in crystallinity. The emission intensity of the BAM phosphor with 10 wt% LiF is about 85% higher than that of the phosphor without LiF and about 200% higher than that of the phosphor without molten salt and LiF. Scanning electron microscopy (SEM) reveal that the as-prepared phosphors have good crystallinity and regular morphology, and most importantly, they are not aggregated. Li+ doping is benefit for the thermal stability and results in a slightly longer decay times of 1.17 μs.

High-temperature XAFS measurement of molten salt systems

NASA Astrophysics Data System (ADS)

Okamoto, Y.; Akabori, M.; Motohashi, H.; Itoh, A.; Ogawa, T.

2002-07-01

A measurement system for high temperature XAFS was developed for investigating the local structure of hygroscopic molten salts like rare earth halides. A solid sample was enclosed in the upper tank of a quartz cell having a sandglass shape under reduced pressure to avoid oxygen and moisture. The measurement was carried out in an electric furnace capable of a highest temperature of 1273 K. After melting, the sample runs down through the melt path with 0.1 mm (or 0.2 mm) thickness to the lower tank. The measurable energy was limited to be above 10 keV due to the absorption of the quartz cell. We confirmed that the measurement of the expensive hygroscopic sample is possible with this system.

New operating strategies for molten salt in line focusing solar fields - Daily drainage and solar receiver preheating

NASA Astrophysics Data System (ADS)

Eickhoff, Martin; Meyer-Grünefeldt, Mirko; Keller, Lothar

2016-05-01

Nowadays molten salt is efficiently used in point concentrating solar thermal power plants. Line focusing systems still have the disadvantage of elevated heat losses at night because of active freeze protection of the solar field piping system. In order to achieve an efficient operation of line focusing solar power plants using molten salt, a new plant design and a novel operating strategy is developed for Linear Fresnel- and Parabolic Trough power plants. Daily vespertine drainage of the solar field piping and daily matutinal refilling of the solar preheated absorber tubes eliminate the need of nocturnal heating of the solar field and reduce nocturnal heat losses to a minimum. The feasibility of this new operating strategy with all its sub-steps has been demonstrated experimentally.

Two-Dimensional Neutronic and Fuel Cycle Analysis of the Transatomic Power Molten Salt Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Betzler, Benjamin R.; Powers, Jeffrey J.; Worrall, Andrew

2017-01-15

This status report presents the results from the first phase of the collaboration between Transatomic Power Corporation (TAP) and Oak Ridge National Laboratory (ORNL) to provide neutronic and fuel cycle analysis of the TAP core design through the Department of Energy Gateway for Accelerated Innovation in Nuclear, Nuclear Energy Voucher program. The TAP design is a molten salt reactor using movable moderator rods to shift the neutron spectrum in the core from mostly epithermal at beginning of life to thermal at end of life. Additional developments in the ChemTriton modeling and simulation tool provide the critical moderator-to-fuel ratio searches andmore » time-dependent parameters necessary to simulate the continuously changing physics in this complex system. Results from simulations with these tools show agreement with TAP-calculated performance metrics for core lifetime, discharge burnup, and salt volume fraction, verifying the viability of reducing actinide waste production with this design. Additional analyses of time step sizes, mass feed rates and enrichments, and isotopic removals provide additional information to make informed design decisions. This work further demonstrates capabilities of ORNL modeling and simulation tools for analysis of molten salt reactor designs and strongly positions this effort for the upcoming three-dimensional core analysis.« less

The use of molten salts as physical models for the study of solidification in metals and semiconductors

NASA Technical Reports Server (NTRS)

Koziol, Jurek K.; Sadoway, Donald R.

1987-01-01

It is presently noted that molten salts possess attributes rendering them attractive as physical models of cast metals in solidification studies. Molten alkali halides have an approximately correct Prandtl number for this modeling of metallic melts, and are transparent to visible light. Attention is given to solidification in the LiCl-KCl system, in order to determine whether such phenomena as solute rejection can be observed and characterized through the application of laser schlieren imaging.

Plutonium (TRU) transmutation and 233U production by single-fluid type accelerator molten-salt breeder (AMSB)

NASA Astrophysics Data System (ADS)

Furukawa, Kazuo; Kato, Yoshio; Chigrinov, Sergey E.

1995-09-01

For practical/industrial disposition of Pu(TRU) by accelerator facility, not only physical soundness and safety but also the following technological rationality should be required: (1) few R&D items including radiation damage, heat removal and material compatibility: (2) few operation/maintenance/processing works; (3) few reproduction of radioactivity; (4) effective energy production in parallel. This will be achieved by the new modification of Th-fertilizing Single-Fluid type Accelerator Molten-Salt Breeder (AMSB), by which a global nuclear energy strategy for next century might be prepared.

Preliminary study on weapon grade uranium utilization in molten salt reactor miniFUJI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aji, Indarta Kuncoro; Waris, A., E-mail: awaris@fi.itb.ac.id

Preliminary study on weapon grade uranium utilization in 25MWth and 50MWth of miniFUJI MSR (molten salt reactor) has been carried out. In this study, a very high enriched uranium that we called weapon grade uranium has been employed in UF{sub 4} composition. The {sup 235}U enrichment is 90 - 95 %. The results show that the 25MWth miniFUJI MSR can get its criticality condition for 1.56 %, 1.76%, and 1.96% of UF{sub 4} with {sup 235}U enrichment of at least 93%, 90%, and 90%, respectively. In contrast, the 50 MWth miniFUJI reactor can be critical for 1.96% of UF{sub 4}more » with {sup 235}U enrichment of at smallest amount 95%. The neutron spectra are almost similar for each power output.« less

Molten salt considerations for accelerator-driven subcritical fission to close the nuclear fuel cycle

NASA Astrophysics Data System (ADS)

Sooby, Elizabeth; Adams, Marvin; Baty, Austin; Gerity, James; McIntyre, Peter; Melconian, Karie; Phongikaroon, Supathorn; Pogue, Nathaniel; Sattarov, Akhdiyor; Simpson, Michael; Tripathy, Prabhat; Tsevkov, Pavel

2013-04-01

The host salt selection, molecular modeling, physical chemistry, and processing chemistry are presented here for an accelerator-driven subcritical fission in a molten salt core (ADSMS). The core is fueled solely with the transuranics (TRU) and long-lived fission products (LFP) from used nuclear fuel. The neutronics and salt composition are optimized to destroy the transuranics by fission and the long-lived fission products by transmutation. The cores are driven by proton beams from a strong-focusing cyclotron stack. One such ADSMS system can destroy the transuranics in the used nuclear fuel produced by a 1GWe conventional reactor. It uniquely provides a method to close the nuclear fuel cycle for green nuclear energy.

Thermodynamics of soluble fission products cesium and iodine in the Molten Salt Reactor

NASA Astrophysics Data System (ADS)

Capelli, E.; Beneš, O.; Konings, R. J. M.

2018-04-01

The present study describes the full thermodynamic assessment of the Li,Cs,Th//F,I system. The existing database for the relevant fluoride salts considered as fuel for the Molten Salt Reactor (MSR) has been extended with two key fission products, cesium and iodine. A complete evaluation of all the common-ion binary and ternary sub-systems of the LiF-ThF4-CsF-LiI-ThI4-CsI system has been performed and the optimized parameters are presented in this work. New equilibrium data have been measured using Differential Scanning Calorimetry and were used to assess the reciprocal ternary systems and confirm the extrapolated phase diagrams. The developed database significantly contributes to the understanding of the behaviour of cesium and iodine in the MSR, which strongly depends on their concentration and chemical form. Cesium bonded with fluorine is well retained in the fuel mixture while in the form of CsI the solubility of these elements is very limited. Finally, the influence of CsI and CsF on the physico-chemical properties of the fuel mixture was calculated as function of composition.

High-temperature molten salt thermal energy storage systems

NASA Technical Reports Server (NTRS)

Petri, R. J.; Claar, T. D.; Tison, R. R.; Marianowski, L. G.

1980-01-01

The results of comparative screening studies of candidate molten carbonate salts as phase change materials (PCM) for advanced solar thermal energy storage applications at 540 to 870 C (1004 to 1600 F) and steam Rankine electric generation at 400 to 540 C (752 to 1004 F) are presented. Alkali carbonates are attractive as latent heat storage materials because of their relatively high storage capacity and thermal conductivity, low corrosivity, moderate cost, and safe and simple handling requirements. Salts were tested in 0.1 kWhr lab scale modules and evaluated on the basis of discharge heat flux, solidification temperature range, thermal cycling stability, and compatibility with containment materials. The feasibility of using a distributed network of high conductivity material to increase the heat flux through the layer of solidified salt was evaluated. The thermal performance of an 8 kWhr thermal energy storage (TES) module containing LiKCO3 remained very stable throughout 5650 hours and 130 charge/discharge cycles at 480 to 535 C (896 to 995 F). A TES utilization concept of an electrical generation peaking subsystem composed of a multistage condensing steam turbine and a TES subsystem with a separate power conversion loop was defined. Conceptual designs for a 100 MW sub e TES peaking system providing steam at 316 C, 427 C, and 454 C (600 F, 800 F, and 850 F) at 3.79 million Pa (550 psia) were developed and evaluated. Areas requiring further investigation have also been identified.

Molten Salt: Concept Definition and Capital Cost Estimate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoddard, Larry; Andrew, Daniel; Adams, Shannon

The Department of Energy’s (DOE’s) Office of Renewable Power (ORP) has been tasked to provide effective program management and strategic direction for all of the DOE’s Energy Efficiency & Renewable Energy’s (EERE’s) renewable power programs. The ORP’s efforts to accomplish this mission are aligned with national energy policies, DOE strategic planning, EERE’s strategic planning, Congressional appropriation, and stakeholder advice. ORP is supported by three renewable energy offices, of which one is the Solar Energy Technology Office (SETO) whose SunShot Initiative has a mission to accelerate research, development and large scale deployment of solar technologies in the United States. SETO hasmore » a goal of reducing the cost of Concentrating Solar Power (CSP) by 75 percent of 2010 costs by 2020 to reach parity with base-load energy rates, and to reduce costs 30 percent further by 2030. The SunShot Initiative is promoting the implementation of high temperature CSP with thermal energy storage allowing generation during high demand hours. The SunShot Initiative has funded significant research and development work on component testing, with attention to high temperature molten salts, heliostats, receiver designs, and high efficiency high temperature supercritical CO 2 (sCO2) cycles. DOE retained Black & Veatch to support SETO’s SunShot Initiative for CSP solar power tower technology in the following areas: 1. Concept definition, including costs and schedule, of a flexible test facility to be used to test and prove components in part to support financing. 2. Concept definition, including costs and schedule, of an integrated high temperature molten salt (MS) facility with thermal energy storage and with a supercritical CO 2 cycle generating approximately 10MWe. 3. Concept definition, including costs and schedule, of an integrated high temperature falling particle facility with thermal energy storage and with a supercritical CO 2 cycle generating

Molten salt thermal energy storage subsystem for Solar Thermal Central Receiver plants

NASA Astrophysics Data System (ADS)

Wells, P. B.; Nassopoulos, G. P.

The development of a low-cost thermal energy storage subsystem for large solar plants is analyzed. Molten nitrate salt is used as both the plant's working fluid and as the storage medium. The storage system comprises a specially designed hot tank to hold salt at a storage temperature of 839 K (1050 F) and a separate carbon steel cold tank to hold the salt after its thermal energy has been extracted to generate steam. The hot tank is lined with insulating firebrick to lower the shell temperature to 561 K (550 F) so that a low-cost carbon steel shell can be used. A preliminary design is described for a large commercial-size plant (1200 MWht). Also described are a laboratory test program for the critical components and the design, construction, and test of a small-scale research experiment at the Central Receiver Test Facility in Albuquerque, New Mexico.

Analysis and test results for a molten salt thermal energy storage system

NASA Astrophysics Data System (ADS)

Sterrett, R. H.; Scott, O. L.

A system has been developed to provide low cost thermal energy storage using molten salt. It consists of a hot tank to store the 565 C (1050 F) salt and a cold tank to store the 289 C (550 F) salt. The hot tank uses internal insulation protected by a liner to enable the use of a carbon steel shell for structural support. Due to the lower salt temperature, the cold tank can be a carbon steel shell with external insulation. This paper describes an analytical method used to predict the thermal performance of such systems and presents experimental data from a Subsystem Research Experiment (SRE) conducted by Martin Marietta Aerospace, Solar Energy Systems under contract from Sandia National Laboratories, Livermore, CA. The results from three of the SRE test cases are compared with the STS model results. These are (1) steady state operation, (2) concurrent charging and discharging, and (3) transient cooldown. The temperature differences between the analytical and experimental results were less than 10%. The internally insulated hot tank performed well.

Molten salt thermal energy storage subsystem for solar thermal central receiver plants

NASA Astrophysics Data System (ADS)

Wells, P. B.; Nassopoulos, G. P.

1982-02-01

The development of a low cost thermal energy storage subsystem for large solar plants is described. Molten nitrate salt is used as both the solar plant working fluid and the storage medium. The storage system consists of a specially designed hot tank to hold salt at a storage temperature of 839K (1050 deg F) and a separate carbon steel cold tank to hold the salt after its thermal energy has been extracted to generate steam. The hot tank is lined with insulating firebrick to reduce the shell temperature to 561K (550 deg F) so that a low cost carbon steel shell is used. The internal insulation is protected from the hot salt by a unique metal liner with orthogonal corrugations to allow for numerous cycles of thermal expansion and contraction. A preliminary design for a large commercial size plant (1200 MWh sub +), a laboratory test program for the critical components, and the design, construction, and test of a small scale (7 MWH sub t) research experiment at the Central Receiver Test Facility in Albuquerque, New Mexico is described.

Stabilization of molten salt materials using metal chlorides for solar thermal storage.

PubMed

Dunlop, T O; Jarvis, D J; Voice, W E; Sullivan, J H

2018-05-29

The effect of a variety of metal-chlorides additions on the melting behavior and thermal stability of commercially available salts was investigated. Ternary salts comprised of KNO 3, NaNO 2, and NaNO 3 were produced with additions of a variety of chlorides (KCl, LiCl, CaCl 2 , ZnCl 2 , NaCl and MgCl 2 ). Thermogravimetric analysis and weight loss experiments showed that the quaternary salt containing a 5 wt% addition of LiCl and KCl led to an increase in short term thermal stability compared to the ternary control salts. These additions allowed the salts to remain stable up to a temperature of 630 °C. Long term weight loss experiments showed an upper stability increase of 50 °C. A 5 wt% LiCl addition resulted in a weight loss of only 25% after 30 hours in comparison to a 61% loss for control ternary salts. Calorimetry showed that LiCl additions allow partial melting at 80 °C, in comparison to the 142 °C of ternary salts. This drop in melting point, combined with increased stability, provided a molten working range increase of almost 100 °C in total, in comparison to the control ternary salts. XRD analysis showed the oxidation effect of decomposing salts and the additional phase created with LiCl additions to allow melting point changes to occur.

Thermal energy storage heat exchanger: Molten salt heat exchanger design for utility power plants

NASA Technical Reports Server (NTRS)

Ferarra, A.; Yenetchi, G.; Haslett, R.; Kosson, R.

1977-01-01

The use of thermal energy storage (TES) in the latent heat of molten salts as a means of conserving fossil fuels and lowering the cost of electric power was evaluated. Public utility systems provided electric power on demand. This demand is generally maximum during late weekday afternoons, with considerably lower overnight and weekend loads. Typically, the average demand is only 60% to 80% of peak load. As peak load increases, the present practice is to purchase power from other grid facilities or to bring older less efficient fossil-fuel plants on line which increase the cost of electric power. The widespread use of oil-fired boilers, gas turbine and diesel equipment to meet peaking loads depletes our oil-based energy resources. Heat exchangers utilizing molten salts can be used to level the energy consumption curve. The study begins with a demand analysis and the consideration of several existing modern fossil-fuel and nuclear power plants for use as models. Salts are evaluated for thermodynamic, economic, corrosive, and safety characteristics. Heat exchanger concepts are explored and heat exchanger designs are conceived. Finally, the economics of TES conversions in existing plants and new construction is analyzed. The study concluded that TES is feasible in electric power generation. Substantial data are presented for TES design, and reference material for further investigation of techniques is included.

Effects assessment of 10 functioning years on the main components of the molten salt PCS experimental facility of ENEA

NASA Astrophysics Data System (ADS)

Gaggioli, Walter; Di Ascenzi, Primo; Rinaldi, Luca; Tarquini, Pietro; Fabrizi, Fabrizio

2016-05-01

In the frame of the Solar Thermodynamic Laboratory, ENEA has improved CSP Parabolic Trough technologies by adopting new advanced solutions for linear tube receivers and by implementing a binary mixture of molten salt (60% NaNO3 and 40% KNO3) [1] as both heat transfer fluid and heat storage medium in solar field and in storage tanks, thus allowing the solar plants to operate at high temperatures up to 550°C. Further improvements have regarded parabolic mirror collectors, piping and process instrumentation. All the innovative components developed by ENEA, together with other standard parts of the plant, have been tested and qualified under actual solar operating conditions on the PCS experimental facility at the ENEA Casaccia Research Center in Rome (Italy). The PCS (Prova Collettori Solari, i.e. Test of Solar Collectors) facility is the main testing loop built by ENEA and it is unique in the world for what concerns the high operating temperature and the fluid used (mixture of molten salt). It consists in one line of parabolic trough collectors (test section of 100 m long life-size solar collectors) using, as heat transfer fluid, the aforesaid binary mixture of molten salt up to 10 bar, at high temperature in the range 270° and 550°C and a flow rate up to 6.5 kg/s. It has been working since early 2004 [2] till now; it consists in a unique closed loop, and it is totally instrumented. In this paper the effects of over ten years qualification tests on the pressurized tank will be presented, together with the characterization of the thermal losses of the piping of the molten salt circuit, and some observations performed on the PCS facility during its first ten years of operation.

Effects of arginine on rabbit muscle creatine kinase and salt-induced molten globule-like state.

PubMed

Ou, Wen-bin; Wang, Ri-Sheng; Lu, Jie; Zhou, Hai-Meng

2003-11-03

The arginine (Arg)-induced unfolding and the salt-induced folding of creatine kinase (CK) have been studied by measuring enzyme activity, fluorescence emission spectra, native polyacrylamide gel electrophoresis and size exclusion chromatography (SEC). The results showed that Arg caused inactivation and unfolding of CK, but there was no aggregation during CK denaturation. The kinetics of CK unfolding followed a one-phase process. At higher concentrations of Arg (>160 mM), the CK dimers were fully dissociated, the alkali characteristic of Arg mainly led to the dissociation of dimers, but not denaturation effect of Arg's guanidine groups on CK. The inactivation of CK occurred before noticeable conformational changes of the whole molecules. KCl induced monomeric and dimeric molten globule-like states of CK denatured by Arg. These results suggest that as a protein denaturant, the effect of Arg on CK differed from that of guanidine and alkali, its denaturation for protein contains the double effects, which acts not only as guanidine hydrochloride but also as alkali. The active sites of CK have more flexibility than the whole enzyme conformation. Monomeric and dimeric molten globule-like states of CK were formed by the salt inducing in 160 and 500 mM Arg H(2)O solutions, respectively. The molten globule-like states indicate that monomeric and dimeric intermediates exist during CK folding. Furthermore, these results also proved the orderly folding model of CK.

Air/molten salt direct-contact heat-transfer experiment and economic analysis

NASA Astrophysics Data System (ADS)

Bohn, M. S.

1983-11-01

Direct-contact heat-transfer coefficients have been measured in a pilot-scale packed column heat exchanger for molten salt/air duty. Two types of commercial tower packings were tested: metal Raschig rings and initial Pall rings. Volumetric heat-transfer coefficients were measured and appeared to depend upon air flow but not on salt flow rate. An economic analysis was used to compare the cost-effectiveness of direct-contact heat exchange with finned-tube heat exchanger in this application. Incorporating the measured volumetric heat-transfer coefficients, a direct-contact system appeared to be from two to five times as cost-effective as a finned-tube heat exchanger, depending upon operating temperature. The large cost advantage occurs for higher operating temperatures (2700(0)C), where high rates of heat transfer and flexibility in materials choice give the cost advantage to the direct-contact heat exchanger.

Plutonium (TRU) transmutation and {sup 233}U production by single-fluid type accelerator molten-salt breeder (AMSB)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furukaw, Kazuo; Kato, Yoshio; Chigrinov, Sergey E.

1995-10-01

For practical/industrial disposition of Pu(TRU) by accelerator facility, not only physical soundness and safety but also the following technological rationality should be required: (1) few R&D items including radiation damage, heat removal and material compatibility; (2) few operation/maintenance/processing works: (3) few reproduction of radioactivity; (4) effective energy production in parallel. This will be achieved by the new modification of Th-fertilizing Single-Fluid type Accelerator Molten-Salt Breeder (AMSB), by which a global nuclear energy strategy for next century might be prepared.

Sintering and Microstructure of BaTiO3 Nano Particles Synthesized by Molten Salt Method.

PubMed

Lee, Chang-Hyun; Shin, Hyo-Soon; Yeo, Dong-Hun; Ha, Gook-Hyun; Nahm, Sahn

2016-05-01

In order to establish thinner dielectric layers in thick film electronic components such as MLCC (Multilayer ceramic capacitor), BaTiO3 nanoparticles have been utilized. However, studies on the synthesis of nanoparticles smaller than 20 nm, the characteristics of the BaTiO3 powder, and the powder's sintering are lacking. Therefore, this paper aims to synthesize BaTiO3 particles smaller than 20 nm by using the molten salt method and evaluate the microstructure and dielectric properties by varying the sintering temperature from 750 degrees C to 1200 degrees C. Through the molten salt method and by using KOH-KCl mixed salt, 20 nm BaTiO3 powder was synthesized at a low temperature of 150 degrees C. Sintering the pellets formed from the synthesized 20 nm BaTiO3 nano powder led to the observation of an unusual phenomenon where the particles grew to approximate sizes below 850 degrees C where densification progressed. At sintering temperatures above 950 degrees C, particles that expanded into rod shapes were observed and these particles were identified to be unreacted TiO2 based on the results of the EDX (Energy Dispersive X-ray Spectroscopy) analysis and phase analysis results.

Tuning upconversion luminescence of LiYF4:Yb3+,Er3+/Tm3+/Ho3+ microcrystals synthesized through a molten salt process.

PubMed

Niu, Na; He, Fei; Wang, Liuzhen; Wang, Lin; Wang, Yan; Gai, Shili; Yang, Piaoping

2014-05-01

In this paper, well-defined tetragonal-phase LiYF4:Yb3+,Er3+/Tm3+/Ho3+ micro-crystals with octahedral morphology were successfully prepared through a surfactant-free molten salt process for the first time. By gradually increasing the LiF content in the NaNO3-KNO3 reaction medium, the crystal phase transforms from a mixture of YF3 and LiYF4 to pure tetragonal-phase LiYF4. The possible formation process for the phase and morphology evolution is also presented. Moreover, upon 980 nm laser diode (LD) excitation, the lanthanide ions (Yb3+, Er3+/Tm3+/Ho3+) doped LiYF4 crystals exhibit intense upconversion emission lights. By tuning the sensitizer concentrations of Yb3+ ions in LiYF4:Yb3+,Er3+, the relative intensities of green and red emissions can be precisely adjusted under single wavelength excitation. Consequently, multicolor upconversion emissions can be obtained. On the other hand, UC mechanisms were also given based on the emission spectra and the plot of luminescence intensity to pump power.

Moderate temperature rechargeable NaNiS2 cells

NASA Technical Reports Server (NTRS)

Abraham, K. M.

1983-01-01

A rechargeable sodium battery of the configuration, liquid Na/beta double prime -Al2O3/molten NaAlCl4, NiS2, operating in the temperature range of 170 to 190 C, is described. This battery is capable of delivering or = to 50 W-hr/1b and 1000 deep discharge/charge cycles.

Nuclear-grade zirconium prepared by combining combustion synthesis with molten-salt electrorefining technique

NASA Astrophysics Data System (ADS)

Li, Hui; Nersisyan, Hayk H.; Park, Kyung-Tae; Park, Sung-Bin; Kim, Jeong-Guk; Lee, Jeong-Min; Lee, Jong-Hyeon

2011-06-01

Zirconium has a low absorption cross-section for neutrons, which makes it an ideal material for use in nuclear reactor applications. However, hafnium typically contained in zirconium causes it to be far less useful for nuclear reactor materials because of its high neutron-absorbing properties. In the present study, a novel effective method has been developed for the production of hafnium-free zirconium. The process includes two main stages: magnesio-thermic reduction of ZrSiO 4 under a combustion mode, to produce zirconium silicide (ZrSi), and recovery of hafnium-free zirconium by molten-salt electrorefining. It was found that, depending on the electrorefining procedure, it is possible to produce zirconium powder with a low hafnium content: 70 ppm, determined by ICP-AES analysis.

Reshaping the folding energy landscape by chloride salt: impact on molten-globule formation and aggregation behavior of carbonic anhydrase.

PubMed

Borén, Kristina; Grankvist, Hannah; Hammarström, Per; Carlsson, Uno

2004-05-21

During chemical denaturation different intermediate states are populated or suppressed due to the nature of the denaturant used. Chemical denaturation by guanidine-HCl (GuHCl) of human carbonic anhydrase II (HCA II) leads to a three-state unfolding process (Cm,NI=1.0 and Cm,IU=1.9 M GuHCl) with formation of an equilibrium molten-globule intermediate that is stable at moderate concentrations of the denaturant (1-2 M) with a maximum at 1.5 M GuHCl. On the contrary, urea denaturation gives rise to an apparent two-state unfolding transition (Cm=4.4 M urea). However, 8-anilino-1-naphthalene sulfonate (ANS) binding and decreased refolding capacity revealed the presence of the molten globule in the middle of the unfolding transition zone, although to a lesser extent than in GuHCl. Cross-linking studies showed the formation of moderate oligomer sized (300 kDa) and large soluble aggregates (>1000 kDa). Inclusion of 1.5 M NaCl to the urea denaturant to mimic the ionic character of GuHCl leads to a three-state unfolding behavior (Cm,NI=3.0 and Cm,IU=6.4 M urea) with a significantly stabilized molten-globule intermediate by the chloride salt. Comparisons between NaCl and LiCl of the impact on the stability of the various states of HCA II in urea showed that the effects followed what could be expected from the Hofmeister series, where Li+ is a chaotropic ion leading to decreased stability of the native state. Salt addition to the completely urea unfolded HCA II also led to an aggregation prone unfolded state, that has not been observed before for carbonic anhydrase. Refolding from this state only provided low recoveries of native enzyme.

Sulfur doped reduced graphene oxides with enhanced catalytic activity for oxygen reduction via molten salt redox-sulfidation.

PubMed

Gu, Yuxing; Chen, Zhigang; Tang, Juanjuan; Xiao, Wei; Mao, Xuhui; Zhu, Hua; Wang, Dihua

2016-12-07

A spontaneous redox reaction of reduced graphene oxide (rGO) in molten Li 2 CO 3 -Na 2 CO 3 -K 2 CO 3 with a small amount of Li 2 SO 4 at 550 °C was applied to synthesize sulfur and sulfur-cobalt doped rGOs (S-rGO/S-Co-rGO). The obtained S-rGOs and S-Co-rGOs show enhanced catalytic activity for the oxygen reduction reaction (ORR) in alkaline aqueous solutions. The onset reduction potential and the half-wave potential of S-Co-rGO are 60 and 40 mV more positive than those of the original rGO, respectively. The reduction current density of S-Co-rGO increases by nearly five times. This study provides a green and continuous molten salt doping approach for the fabrication of heteroatom-doped graphene with excellent catalytic activity for the ORR.

Recycling Titanium and Its Alloys by Utilizing Molten Salt

NASA Astrophysics Data System (ADS)

Okabe, Toru H.; Taninouchi, Yu-ki

It is commonly believed that the deoxidation of titanium (Ti), or the direct removal of oxygen (O) dissolved in metallic Ti, is practically impossible when magnesium (Mg) is used as the deoxidizing agent. In recent years, it has been experimentally demonstrated that O dissolved in Ti can be directly removed using MgCl2 molten salt electrolysis. By the electrochemical deoxidation technique, Ti wires containing 0.12 mass% O were deoxidized to less than 0.02 mass% O. In some cases, the concentration of O in the Ti wires was reduced to the level of 0.01 mass% O, which cannot be attained using the current Kroll process. The possible application of this deoxidation technique to practical industrial recycling processes is also discussed.

Thermo-mechanical and optical optimization of the molten salt receiver for a given heliostat field

NASA Astrophysics Data System (ADS)

Augsburger, Germain; Das, Apurba K.; Boschek, Erik; Clark, Michael M.

2016-05-01

The tower type molten salt solar thermal power plant has proven to be advantageous over other utility scale solar power plant configurations due to its scalability and provision of storage, thereby improving the dispatchability. The configuration consists of a molten salt central receiver (MSCR) located atop an optimally located tower within a heliostat field with thousands of mirrors. The MSCR receives the concentrated energy from the heliostat field which heats a molten salt heat transfer fluid for thermal storage and utilization in producing steam as and when required for power generation. The MSCR heat transfer surface consists of banks of tangent tubes arranged in panels. The combined cost of the heliostat field and the receiver is 40%-50% of the total plant cost, which calls for optimization to maximize their utilization. Several previous studies have looked into the optimum solar power plant size based on various site conditions. However, the combined optimization of the receiver and the heliostat field has not been reported before. This study looks into the optimum configuration of the receiver for a given heliostat field. An in-house tool has been developed to select and rank a few receiver surface configurations (typically <50) from a list of hundreds of thousands of possible options. The operating limits which the heliostat field needs to obey are defined for the ranked surface configurations based on several different design considerations (e.g. mechanical integrity, corrosion limits). The thermal output of the receiver configurations for a given heliostat field is maximized. A combined rank indicating the optimum configurations in descending order of preference is presented based on the performance and various other practical considerations (e.g. total surface area, cost of material, ability of aiming strategies to distribute the flux). The methodology thus provided can be used as a guideline to arrive at an optimum receiver configuration for a given

Application of Molten Salt Reactor Technology to MMW In-Space NEP and Surface Power Missions

NASA Technical Reports Server (NTRS)

Patton, Bruce; Sorensen, Kirk; Rodgers, Stephen (Technical Monitor)

2002-01-01

Anticipated manned nuclear electric propulsion (NEP) and planetary surface power missions will require multimegawatt nuclear reactors that are lightweight, operationally robust, and scalable in power for widely varying scientific mission objectives. Molten salt reactor technology meets all of these requirements and offers an interesting alternative to traditional multimegawatt gas-cooled and liquid metal concepts.

Plutonium (TRU) transmutation and {sup 233}U production by single-fluid type accelerator molten-salt breeder (AMSB)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furukawa, Kazuo; Kato, Yoshio; Chigrinov, Sergey E.

1995-09-15

For practical/industrial disposition of Pu(TRU) by accelerator facility, not only physical soundness and safety but also the following technological rationality should be required: (1) few R and D items including radiation damage, heat removal and material compatibility: (2) few operation/maintenance/processing works; (3) few reproduction of radioactivity; (4) effective energy production in parallel. This will be achieved by the new modification of Th-fertilizing Single-Fluid type Accelerator Molten-Salt Breeder (AMSB), by which a global nuclear energy strategy for next century might be prepared.

Stabilization/solidification of radioactive salt waste by using xSiO2-yAl2O3-zP2O5 (SAP) material at molten salt state.

PubMed

Park, Hwan-Seo; Kim, In-Tae; Cho, Yong-Zun; Eun, Hee-Chul; Lee, Han-Soo

2008-12-15

The molten salt waste from the pyroprocess is one of the problematic wastes to directly apply a conventional process such as vitrification or ceramization. This study suggested a novel method using a reactive material for metal chlorides at a molten temperature of salt waste, and then converting them into manageable product at a high temperature. The inorganic composite, SAP (SiO2-Al2O3-P2O5), synthesized by a conventional sol-gel process has three or four distinctive domains that are bonded sequentially, Si-O-Si-O-A-O-P-O-P. The P-rich phase in the SAP composite is unstable for producing a series of reactive sites when in contact with a molten LiCl salt. After the reaction, metal aluminosilicate, metal aluminophosphate, metal phosphates and gaseous chlorines are generated. From this process, the volatile salt waste is stabilized and it is possible to apply a high temperature process. The reaction products were fabricated successfully by using a borosilicate glass with an arbitrary composition as a chemical binder. There was a low possibility for the valorization of radionuclides up to 1200 degrees C, based on the result of the thermo gravimetric analysis. The Cs and Sr leach rates by the PCT-A method were about 1 x 10(-3) g/(m2 day). For the final disposal of the problematic salt waste, this approach suggested the design concept of an effective stabilizer for metal chlorides and revealed the chemical route to the fabrication of monolithic wasteform by using a composite as an example. Using this method, we could obtain a higher disposal efficiency and lower waste volume, compared with the present immobilization methods.

Archimede solar energy molten salt parabolic trough demo plant: Improvements and second year of operation

NASA Astrophysics Data System (ADS)

Maccari, Augusto; Donnola, Sandro; Matino, Francesca; Tamano, Shiro

2016-05-01

Since July 2013, the first stand-alone Molten Salt Parabolic Trough (MSPT) demo plant, which was built in collaboration with Archimede Solar Energy and Chiyoda Corporation, is in operation, located adjacent to the Archimede Solar Energy (ASE) manufacturing plant in Massa Martana (Italy). During the two year's operating time frame, the management of the demo plant has shown that MSPT technology is a suitable and reliable option. Several O&M procedures and tests have been performed, as Heat Loss and Minimum Flow Test, with remarkable results confirming that this technology is ready to be extended to standard size CSP plant, if the plant design takes into account molten salt peculiarities. Additionally, the plant has been equipped on fall 2014 with a Steam Generator system by Chiyoda Corporation, in order to test even this important MSPT plant subsystem and to extend the solar field active time, overcoming the previous lack of an adequate thermal load. Here, a description of the plant improvements and the overall plant operation figures will be presented.

Investigation of residual anode material after electrorefining uranium in molten chloride salt

NASA Astrophysics Data System (ADS)

Rose, M. A.; Williamson, M. A.; Willit, J.

2015-12-01

A buildup of material at uranium anodes during uranium electrorefining in molten chloride salts has been observed. Potentiodynamic testing has been conducted using a three electrode cell, with a uranium working electrode in both LiCl/KCl eutectic and LiCl each containing ∼5 mol% UCl3. The anodic current response was observed at 50° intervals between 450 °C and 650 °C in the eutectic salt. These tests revealed a buildup of material at the anode in LiCl/KCl salt, which was sampled at room temperature, and analyzed using ICP-MS, XRD and SEM techniques. Examination of the analytical data, current response curves and published phase diagrams has established that as the uranium anode dissolves, the U3+ ion concentration in the diffusion layer surrounding the electrode rises precipitously to levels, which may at low temperatures exceed the solubility limit for UCl3 or in the case of the eutectic salt for K2UCl5. The reduction in current response observed at low temperature in eutectic salt is eliminated at 650 °C, where K2UCl5 is absent due to its congruent melting and only simple concentration polarization effects are seen. In LiCl similar concentration effects are seen though significantly longer time at applied potential is required to effect a reduction in the current response as compared to the eutectic salt.

High-temperature molten salt thermal energy storage systems for solar applications

NASA Technical Reports Server (NTRS)

Petri, R. J.; Claar, T. D.; Ong, E.

1983-01-01

Experimental results of compatibility screening studies of 100 salt/containment/thermal conductivity enhancement (TCE) combinations for the high temperature solar thermal application range of 704 deg to 871 C (1300 to 1600 F) are presented. Nine candidate containment/HX alloy materials and two TCE materials were tested with six candidate solar thermal alkali and alkaline earth carbonate storage salts (both reagent and technical grade of each). Compatibility tests were conducted with salt encapsulated in approx. 6.0 inch x 1 inch welded containers of test material from 300 to 3000 hours. Compatibility evaluations were end application oriented, considering the potential 30 year lifetime requirement of solar thermal power plant components. Analyses were based on depth and nature of salt side corrosion of materials, containment alloy thermal aging effects, weld integrity in salt environment, air side containment oxidation, and chemical and physical analyses of the salt. A need for more reliable, and in some cases first time determined thermophysical and transport property data was also identified for molten carbonates in the 704 to 871 C temperature range. In particular, accurate melting point (mp) measurements were performed for Li2CO3 and Na2CO3 while melting point, heat of fusion, and specific heat determinations were conducted on 81.3 weight percent Na2CO3-18.7 weight percent K2CO3 and 52.2 weight percent BaCO3-47.8 weight percent Na2CO3 to support future TES system design and ultimate scale up of solar thermal energy storage (TES) subsystems.

Preparation of SiC/SiO2 core-shell nanowires via molten salt mediated carbothermal reduction route

NASA Astrophysics Data System (ADS)

Zhang, Ju; Yan, Shuai; Jia, Quanli; Huang, Juntong; Lin, Liangxu; Zhang, Shaowei

2016-06-01

The growth of silicon carbide (SiC) crystal generally requires a high temperature, especially when low quality industrial wastes are used as the starting raw materials. In this work, SiC/SiO2 core-shell nanowires (NWs) were synthesized from low cost silica fume and sucrose via a molten salt mediated carbothermal reduction (CR) route. The molten salt was found to be effective in promoting the SiC growth and lowering the synthesis temperature. The resultant NWs exhibited a heterostructure composed of a 3C-SiC core of 100 nm in diameter and a 5-10 nm thick amorphous SiO2 shell layer. The photoluminescence spectrum of the achieved SiC NWs displayed a significant blue shift (a dominant luminescence at round 422 nm), which suggested that they were high quality and could be a promising candidate material for future optoelectronic applications.

Preparation of Binary and Ternary Oxides by Molten Salt Method and its Electrochemical Properties

NASA Astrophysics Data System (ADS)

Reddy, M. V.; Theng, L. Pei; Soh, Hulbert; Beichen, Z.; Jiahuan, F.; Yu, C.; Ling, A. Yen; Andreea, L. Y.; Ng, C. H. Justin; Liang, T. J. L. Galen; Ian, M. F.; An, H. V. T.; Ramanathan, K.; Kevin, C. W. J.; Daryl, T. Y. W.; Hao, T. Yi; Loh, K. P.; Chowdari, B. V. R.

2013-07-01

We report simple binary oxides namely SnO2, TiO2, CuO, MnO2, Fe2O3, Co3O4 and ternary oxides like MnCo2O4 by molten salt method at a temperature range of 280°C to 950°C in air and discuss the effect of morphology, crystal structure and electrochemical properties of binary and ternary oxides. Materials were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) surface area methods. XRD patterns showed all MSM prepared materials exhibited characteristic lattice parameter values. BET surface area varies depending on the nature of the material, molten salt and preparation temperature and the obtained values are in the range, 1 to 160 m2/g. Electrochemical properties were studied using cyclic voltammetry (CV) and electrochemical performance studies were carried in the voltage range, 0.005-1.0V for SnO2, 1.0-2.8V for TiO2 and Fe2O3, MCo2O4 (M = Co, Mn), MnO2 and CuO were cycled in the range, 0.005-3.0V. At a current rates of 30-100 mA/g and a scan rate of 0.058 mV/sec was used for galvanostatic cycling and cyclic voltammetry. SnO2 showed that an alloying-de-alloying reaction occurs at ˜0.2 and ˜0.5 V vs. Li. TiO2 main intercalation and de-interaction reactions at ˜1.7 and ˜1.8 V vs. Li. Co3O4, MnCo2O4, and MnO2 main discharge potentials at ˜1.2, 0.9V and 0.4V, resp. and charge potentials peak ˜2.0V and 1.5V vs. Li. CuO prepared at 750°C exhibited main anodic peak at ˜2.45V and cathodic peaks at ˜0.85V and ˜1.25V. We discussed the possible reaction mechanisms and Li-storage performance values in detail.

Dynamic detailed model of a molten salt tower receiver, with ThermoSysPro library: Impacts of several failures or operational transients on the receiver dynamic behavior

NASA Astrophysics Data System (ADS)

Hefni, Baligh El; Bourdil, Charles

2017-06-01

Molten salt technology represents nowadays the most cost-effective technology for electricity generation for solar power plant. The molten salt tower receiver is based on a field of individually sun-tracking mirrors (heliostats) that reflect the incident sunshine to a receiver at the top of a centrally located tower. The objective of this study is to assess the impact of several transients issued from different scenarios (failure or normal operation mode) on the receiver dynamic behavior. A dynamic detailed model of Solar Two molten salt central receiver has been developed. The component model is meant to be used for receiver modeling with the ThermoSysPro library, developed by EDF. The paper also gives the results of the dynamic simulation for the selected scenarios on Solar Two receiver.

Heat transfer and pressure drop measurements in an air/molten salt direct-contact heat exchanger

NASA Astrophysics Data System (ADS)

Bohn, Mark S.

1988-11-01

This paper presents a comparison of experimental data with a recently published model of heat exchange in irrigated packed beds. Heat transfer and pressure drop were measured in a 150 mm (ID) column with a 610 mm bed of metal Pall rings. Molten nitrate salt and preheated air were the working fluids with a salt inlet temperature of approximately 440 C and air inlet temperatures of approximately 230 C. A comparison between the experimental data and the heat transfer model is made on the basis of heat transfer from the salt. For the range of air and salt flow rates tested, 0.3 to 1.2 kg/sq m/s air flow and 6 to 18 kg/sq m/s salt flow, the data agree with the model within 22 percent standard deviation. In addition, a model for the column pressure drop was validated, agreeing with the experimental data within 18 percent standard deviation over the range of column pressure drop from 40 to 1250 Pa/m.

Cation and anion dependence of stable geometries and stabilization energies of alkali metal cation complexes with FSA(-), FTA(-), and TFSA(-) anions: relationship with physicochemical properties of molten salts.

PubMed

Tsuzuki, Seiji; Kubota, Keigo; Matsumoto, Hajime

2013-12-19

Stable geometries and stabilization energies (Eform) of the alkali metal complexes with bis(fluorosulfonyl)amide, (fluorosulfonyl)(trifluoromethylslufonyl)amide and bis(trifluoromethylsulfonyl)amide (FSA(-), FTA(-) and TFSA(-)) were studied by ab initio molecular orbital calculations. The FSA(-) complexes prefer the bidentate structures in which two oxygen atoms of two SO2 groups have contact with the metal cation. The FTA(-) and TFSA(-) complexes with Li(+) and Na(+) prefer the bidentate structures, while the FTA(-) and TFSA(-) complexes with Cs(+) prefer tridentate structures in which the metal cation has contact with two oxygen atoms of an SO2 group and one oxygen atom of another SO2 group. The two structures are nearly isoenergetic in the FTA(-) and TFSA(-) complexes with K(+) and Rb(+). The magnitude of Eform depends on the alkali metal cation significantly. The Eform calculated for the most stable TFSA(-) complexes with Li(+), Na(+), K(+), Rb(+) and Cs(+) cations at the MP2/6-311G** level are -137.2, -110.5, -101.1, -89.6, and -84.1 kcal/mol, respectively. The viscosity and ionic conductivity of the alkali TFSA molten salts have strong correlation with the magnitude of the attraction. The viscosity increases and the ionic conductivity decreases with the increase of the attraction. The melting points of the alkali TFSA and alkali BETA molten salts also have correlation with the magnitude of the Eform, which strongly suggests that the magnitude of the attraction play important roles in determining the melting points of these molten salts. The anion dependence of the Eform calculated for the complexes is small (less than 2.9 kcal/mol). This shows that the magnitude of the attraction is not the cause of the low melting points of alkali FTA molten salts compared with those of corresponding alkali TFSA molten salts. The electrostatic interactions are the major source of the attraction in the complexes. The electrostatic energies for the most stable TFSA

Intergranular tellurium cracking of nickel-based alloys in molten Li, Be, Th, U/F salt mixture

NASA Astrophysics Data System (ADS)

Ignatiev, Victor; Surenkov, Alexander; Gnidoy, Ivan; Kulakov, Alexander; Uglov, Vadim; Vasiliev, Alexander; Presniakov, Mikhail

2013-09-01

In Russia, R&D on Molten Salt Reactor (MSR) are concentrated now on fast/intermediate spectrum concepts which were recognized as long term alternative to solid fueled fast reactors due to their attractive features: strong negative feedback coefficients, easy in-service inspection, and simplified fuel cycle. For high-temperature MSR corrosion of the metallic container alloy in primary circuit is the primary concern. Key problem receiving current attention include surface fissures in Ni-based alloys probably arising from fission product tellurium attack. This paper summarizes results of corrosion tests conducted recently to study effect of oxidation state in selected fuel salt on tellurium attack and to develop means of controlling tellurium cracking in the special Ni-based alloys recently developed for molten salt actinide recycler and tranforming (MOSART) system. Tellurium corrosion of Ni-based alloys was tested at temperatures up to 750 °C in stressed and unloaded conditions in molten LiF-BeF2 salt mixture fueled by about 20 mol% of ThF4 and 2 mol% of UF4 at different [U(IV)]/[U(III)] ratios: 0.7, 4, 20, 100 and 500. Following Ni-based alloys (in mass%): HN80М-VI (Mo—12, Cr—7.6, Nb—1.5), HN80МТY (Mo—13, Cr—6.8, Al—1.1, Ti—0.9), HN80МТW (Mo—9.4, Cr—7.0, Ti—1.7, W—5.5) and ЕМ-721 (W—25.2, Cr—5.7, Ti—0.17) were used for the study in the corrosion facility. If the redox state the fuel salt is characterized by uranium ratio [U(IV)]/[U(III)] < 1 the alloys' specimens get a more negative stationary electrode potential than equilibrium electrode potentials of some uranium intermetallic compounds and alloys with nickel and molybdenum. This leads to spontaneous behavior of alloy formation processes on the specimens' surface and further diffusion of uranium deep into the metallic phase. As consequence of this films of intermetallic compounds and alloys of nickel, molybdenum, tungsten with uranium are formed on the alloys specimens' surface

Communication—Quantitative Voltammetric Analysis of High Concentration Actinides in Molten Salts

DOE PAGES

Hoyt, Nathaniel C.; Willit, James L.; Williamson, Mark A.

2017-01-18

Previous electroanalytical studies have shown that cyclic voltammetry can provide accurate quantitative measurements of actinide concentrations at low weight loadings in molten salts. However, above 2 wt%, the techniques were found to underpredict the concentrations of the reactant species. Here this work will demonstrate that much of the discrepancy is caused by uncompensated resistance and cylindrical diffusion. An improved electroanalytical approach has therefore been developed using the results of digital simulations to take these effects into account. This approach allows for accurate electroanalytical predictions across the full range of weight loadings expected to be encountered in operational nuclear fuel processingmore » equipment.« less

Communication—Quantitative Voltammetric Analysis of High Concentration Actinides in Molten Salts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoyt, Nathaniel C.; Willit, James L.; Williamson, Mark A.

Previous electroanalytical studies have shown that cyclic voltammetry can provide accurate quantitative measurements of actinide concentrations at low weight loadings in molten salts. However, above 2 wt%, the techniques were found to underpredict the concentrations of the reactant species. Here this work will demonstrate that much of the discrepancy is caused by uncompensated resistance and cylindrical diffusion. An improved electroanalytical approach has therefore been developed using the results of digital simulations to take these effects into account. This approach allows for accurate electroanalytical predictions across the full range of weight loadings expected to be encountered in operational nuclear fuel processingmore » equipment.« less

Computational Thermodynamic Modeling of Hot Corrosion of Alloys Haynes 242 and Hastelloy TM N for Molten Salt Service in Advanced High Temperature Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

V. Glazoff, Michael; Charit, Indrajt; Sabharwall, Piyush

An evaluation of thermodynamic aspects of hot corrosion of the superalloys Haynes 242 and HastelloyTM N in the eutectic mixtures of KF and ZrF4 is carried out for development of Advanced High Temperature Reactor (AHTR). This work models the behavior of several superalloys, potential candidates for the AHTR, using computational thermodynamics tool (ThermoCalc), leading to the development of thermodynamic description of the molten salt eutectic mixtures, and on that basis, mechanistic prediction of hot corrosion. The results from these studies indicated that the principal mechanism of hot corrosion was associated with chromium leaching for all of the superalloys described above.more » However, HastelloyTM N displayed the best hot corrosion performance. This was not surprising given it was developed originally to withstand the harsh conditions of molten salt environment. However, the results obtained in this study provided confidence in the employed methods of computational thermodynamics and could be further used for future alloy design efforts. Finally, several potential solutions to mitigate hot corrosion were proposed for further exploration, including coating development and controlled scaling of intermediate compounds in the KF-ZrF4 system.« less

Corrosion behavior of plasma-sprayed Al 2O 3-Cr 2O 3 coatings in hot lithium molten salt

NASA Astrophysics Data System (ADS)

Cho, Soo Haeng; Park, Sung Bin; Kang, Dae Seong; Jeong, Myeong Soo; Park, Heong; Hur, Jin Mok; Lee, Han Soo

2010-04-01

In this study, hot corrosion studies were performed on bare as well as coated superalloy specimens after exposure to molten lithium chloride environment at 675 °C for 216 h under an oxidizing atmosphere. The substrates of the IN713LC superalloy specimens were sprayed with an aluminized NiCrAlY bond coat and then with an Al 2O 3-Cr 2O 3 top coat. The as-coated and tested specimens were examined by optical microscopy (OM), scanning electron microscopy (SEM)/X-ray energy dispersive spectrometry (EDS) and X-ray diffraction (XRD), respectively. The bare superalloy reveals an obvious weight loss, and the scale formed on the surface of the bare superalloy was spalled due to the rapid scale growth and thermal stress. The top coatings showed a much better hot corrosion resistance in the presence of LiCl-3 wt.% Li 2O molten salt when compared with those of the uncoated superalloy and the aluminized bond coatings. These coatings have been found to be beneficial for increasing to the hot corrosion resistance of the structural materials for handling high temperature lithium molten salts.

Assessment of the Neutronic and Fuel Cycle Performance of the Transatomic Power Molten Salt Reactor Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robertson, Sean; Dewan, Leslie; Massie, Mark

This report presents results from a collaboration between Transatomic Power Corporation (TAP) and Oak Ridge National Laboratory (ORNL) to provide neutronic and fuel cycle analysis of the TAP core design through the Department of Energy Gateway for Accelerated Innovation in Nuclear (GAIN) Nuclear Energy Voucher program. The TAP concept is a molten salt reactor using configurable zirconium hydride moderator rod assemblies to shift the neutron spectrum in the core from mostly epithermal at beginning of life to thermal at end of life. Additional developments in the ChemTriton modeling and simulation tool provide the critical moderator-to-fuel ratio searches and time-dependent parametersmore » necessary to simulate the continuously changing physics in this complex system. The implementation of continuous-energy Monte Carlo transport and depletion tools in ChemTriton provide for full-core three-dimensional modeling and simulation. Results from simulations with these tools show agreement with TAP-calculated performance metrics for core lifetime, discharge burnup, and salt volume fraction, verifying the viability of reducing actinide waste production with this concept. Additional analyses of mass feed rates and enrichments, isotopic removals, tritium generation, core power distribution, core vessel helium generation, moderator rod heat deposition, and reactivity coeffcients provide additional information to make informed design decisions. This work demonstrates capabilities of ORNL modeling and simulation tools for neutronic and fuel cycle analysis of molten salt reactor concepts.« less

Dip-coated ZrO2-Y2O3 coatings tested in molten salts for CSP applications

NASA Astrophysics Data System (ADS)

Pérez, Francisco Javier; Encinas-Sánchez, Víctor; Lasanta, María Isabel; de Miguel, María Teresa; García-Martín, Gustavo

2017-06-01

In the present work, the behaviour of ZrO2 - Y2O3 coatings in contact with molten salts at 500 °C has been studied. The coatings were prepared by sol-gel and deposited by dip-coating on AISI 304 specimens previously prepared by sanding and polishing. The behaviour in contact with molten salt was studied through static corrosion tests by the immersion of the coated samples in an alkali-nitrate mixture with a composition of 60 wt.% NaNO3/40 wt.% KNO3 (commonly known as Solar Salt). Prior to test, the deposited coatings were characterized using Scanning Electron Microscopy and X-Ray Diffraction, showing a compacted, homogeneous and uniform aspect and t-YSZ as main component. After corrosion tests, the samples were characterized via gravimetric, Scanning Electron Microscopy and X-Ray Diffraction. The results show a good behaviour of the coated samples compared with the bare coupon samples. However after 1000 h of testing m-ZrO2 appears in the composition,. At this preliminary study, results confirm the suitability of ZrO2 - Y2O3 coatings in solar applications after those working hours, although it is necessary to optimize the coating and study its behaviour at longer times.

Solar thermal power & gas turbine hybrid design with molten salt storage tank

NASA Astrophysics Data System (ADS)

Martín, Fernando; Wiesenberg, Ralf; Santana, Domingo

2017-06-01

Taking into consideration the need to decelerate the global climatic change, power generation has to shift from burning fossil fuel to renewable energy source in short medium period of time. In this work, we are presenting a new model of a solar-gas natural hybrid power cycle with the main aim of decoupling the solar generation system from the gas turbine system. The objective is to have high solar power contribution compared to conventional ISCC plants [2], producing firm and dispatchable electricity at the same time. The decoupling is motivated by the low solar contribution reached by the ISCC, which is technically limited to maximum of 15%, [4]. In our case, we have implemented a solar tower with molten salts as working fluid. Central receiver systems get higher performance than others systems, like parabolic trough technology [1], due to the higher temperature achieved in the heat transferred fluid HTF, close to 560°C.

A new simple synthesis of CdS nano-particles by composite-molten-salt method and their high photocatalytic degradation activity

NASA Astrophysics Data System (ADS)

Xiang, Donghu; Zhu, Yabo; Cai, Cunjin; He, Zhanjun; Liu, Zhangsheng; Yin, Dagen; Luo, Jin

2011-12-01

Nano-CdS crystal has been succesfully synthesized by composite molten salt (CMS) method for the first time, using composite molten salt as a reaction solvent, sodium sulfide and cadmium nitrate hexahydrate as reactants at temperature of 200 °C for 24 h in the absence of organic dispersant or capping agents. X-ray diffraction and field emission scanning electron microscopy (FESEM) images indicated that the as-synthesized product were well crystallized and belonged to nano-scale. Their UV-vis absorption spectrum demonstrated a band gap of 2.49 eV corresponding to the absorption edge of 499 nm. The experimental result of photocatalytic degradation on methyl orange by the nano-CdS showed much better photocatalysis than that by the commercial CdS powder under the irradiation of ultraviolet light source.

Steady RANS methodology for calculating pressure drop in an in-line molten salt compact crossflow heat exchanger

DOE PAGES

Carasik, Lane B.; Shaver, Dillon R.; Haefner, Jonah B.; ...

2017-08-21

We report the development of molten salt cooled reactors (MSR) and fluoride-salt cooled high temperature reactors (FHR) requires the use of advanced design tools for the primary heat exchanger design. Due to geometric and flow characteristics, compact (pitch to diameter ratios equal to or less than 1.25) heat exchangers with a crossflow flow arrangement can become desirable for these reactors. Unfortunately, the available experimental data is limited for compact tube bundles or banks in crossflow. Computational Fluid Dynamics can be used to alleviate the lack of experimental data in these tube banks. Previous computational efforts have been primarily focused onmore » large S/D ratios (larger than 1.4) using unsteady Reynolds averaged Navier-Stokes and Large Eddy Simulation frameworks. These approaches are useful, but have large computational requirements that make comprehensive design studies impractical. A CFD study was conducted with steady RANS in an effort to provide a starting point for future design work. The study was performed for an in-line tube bank geometry with FLiBe (LiF-BeF2), a frequently selected molten salt, as the working fluid. Based on the estimated pressure drops, the pressure and velocity distributions in the domain, an appropriate meshing strategy was determined and presented. Periodic boundaries in the spanwise direction transverse flow were determined to be an appropriate boundary condition for reduced computational domains. The domain size was investigated and a minimum of 2-flow channels for a domain is recommended to ensure the behavior is accounted for. Finally, the standard low Re κ-ε (Lien) turbulence model was determined to be the most appropriate for steady RANS of this case at the time of writing.« less

Steady RANS methodology for calculating pressure drop in an in-line molten salt compact crossflow heat exchanger

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carasik, Lane B.; Shaver, Dillon R.; Haefner, Jonah B.

We report the development of molten salt cooled reactors (MSR) and fluoride-salt cooled high temperature reactors (FHR) requires the use of advanced design tools for the primary heat exchanger design. Due to geometric and flow characteristics, compact (pitch to diameter ratios equal to or less than 1.25) heat exchangers with a crossflow flow arrangement can become desirable for these reactors. Unfortunately, the available experimental data is limited for compact tube bundles or banks in crossflow. Computational Fluid Dynamics can be used to alleviate the lack of experimental data in these tube banks. Previous computational efforts have been primarily focused onmore » large S/D ratios (larger than 1.4) using unsteady Reynolds averaged Navier-Stokes and Large Eddy Simulation frameworks. These approaches are useful, but have large computational requirements that make comprehensive design studies impractical. A CFD study was conducted with steady RANS in an effort to provide a starting point for future design work. The study was performed for an in-line tube bank geometry with FLiBe (LiF-BeF2), a frequently selected molten salt, as the working fluid. Based on the estimated pressure drops, the pressure and velocity distributions in the domain, an appropriate meshing strategy was determined and presented. Periodic boundaries in the spanwise direction transverse flow were determined to be an appropriate boundary condition for reduced computational domains. The domain size was investigated and a minimum of 2-flow channels for a domain is recommended to ensure the behavior is accounted for. Finally, the standard low Re κ-ε (Lien) turbulence model was determined to be the most appropriate for steady RANS of this case at the time of writing.« less

Molten salt-supported polycondensation of optically active diacid monomers with an aromatic thiazole-bearing diamine using microwave irradiation.

PubMed

Mallakpour, Shadpour; Zadehnazari, Amin

2014-05-01

Microwave heating was used to prepare optically active thiazole-bearing poly(amide-imide)s. Polymerization reactions were carried out in the molten tetrabutylammonium bromide as a green molten salt medium and triphenyl phosphite as the homogenizer. Structural elucidation of the compounds was performed by Fourier transform infrared and NMR spectroscopic data and elemental analysis results. The polymeric samples were readily soluble in various organic solvents, forming low-colored and flexible thin films via solution casting. They showed high thermal stability with decomposition temperature being above 360 °C. They were assembled randomly in a nanoscale size.

Molten salt-supported polycondensation of optically active diacid monomers with an aromatic thiazole-bearing diamine using microwave irradiation

PubMed Central

Mallakpour, Shadpour; Zadehnazari, Amin

2013-01-01

Microwave heating was used to prepare optically active thiazole-bearing poly(amide-imide)s. Polymerization reactions were carried out in the molten tetrabutylammonium bromide as a green molten salt medium and triphenyl phosphite as the homogenizer. Structural elucidation of the compounds was performed by Fourier transform infrared and NMR spectroscopic data and elemental analysis results. The polymeric samples were readily soluble in various organic solvents, forming low-colored and flexible thin films via solution casting. They showed high thermal stability with decomposition temperature being above 360 °C. They were assembled randomly in a nanoscale size. PMID:25685498

A molten Salt Am242M Production Reactor for Space Applications

NASA Technical Reports Server (NTRS)

Emrich, William

2005-01-01

The use of Am242m holds great promise for increasing the efficiency nuclear thermal rocket engines. Because Am242m has the highest fission cross section of any known isotope (1000's of barns), its extremely high reactivity may be used to directly heat a propellant gas with fission fragments. Since this isotope does not occur naturally, it must be bred in special production reactors designed for that purpose. The primary advantage to using molten salt reactors for breeding Am242m is that the reactors can be reprocessed continually yielding a constant rate of production of the isotope. Once built and initially fueled, the reactor will continually breed the additional fuel it needs to remain critical. The only feedstock required is a salt of U238. No enriched fuel is required during normal operation and all fissile material, except the Am242m, is maintained in a closed loop. For a reactor operating at 200 MW several kilograms of Am242m may be bred each year.

Hot filament technique for measuring the thermal conductivity of molten lithium fluoride

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.; Perry, William D.

1990-01-01

Molten salts, such as lithium fluoride, are attractive candidates for thermal energy storage in solar dynamic space power systems because of their high latent heat of fusion. However, these same salts have poor thermal conductivities which inhibit the transfer of heat into the solid phase and out of the liquid phase. One concept for improving the thermal conductivity of the thermal energy storage system is to add a conductive filler material to the molten salt. High thermal conductivity pitch-based graphite fibers are being considered for this application. Although there is some information available on the thermal conductivity of lithium fluoride solid, there is very little information on lithium fluoride liquid, and no information on molten salt graphite fiber composites. This paper describes a hot filament technique for determining the thermal conductivity of molten salts. The hot filament technique was used to find the thermal conductivity of molten lithium fluoride at 930 C, and the thermal conductivity values ranged from 1.2 to 1.6 W/mK. These values are comparable to the slightly larger value of 5.0 W/mK for lithium fluoride solid. In addition, two molten salt graphite fiber composites were characterized with the hot filament technique and these results are also presented.

Molten salt parabolic trough system with synthetic oil preheating

NASA Astrophysics Data System (ADS)

Yuasa, Minoru; Hino, Koichi

2017-06-01

Molten salt parabolic trough system (MSPT), which can heat the heat transfer fluid (HTF) to 550 °C has a better performance than a synthetic oil parabolic trough system (SOPT), which can heat the HTF to 400 °C or less. The utilization of HTF at higher temperature in the parabolic trough system is able to realize the design of a smaller size of storage tank and higher heat to electricity conversion efficiency. However, with MSPT there is a great amount of heat loss at night so it is necessary to circulate the HTF at a high temperature of about 290 °C in order to prevent solidification. A new MSPT concept with SOPT preheating (MSSOPT) has been developed to reduce the heat loss at night. In this paper, the MSSOPT system, its performance by steady state analysis and annual performance analysis are introduced.

Investigation of concentration-dependence of thermodynamic properties of lanthanum, yttrium, scandium and terbium in eutectic LiCl-KCl molten salt

NASA Astrophysics Data System (ADS)

Wang, Yafei; Zhou, Wentao; Zhang, Jinsuo

2016-09-01

Thermodynamic properties of rare earth metals in LiCl-KCl molten salt electrolyte are crucial to the development of electrochemical separation for the treatment of used nuclear fuels. In the present study, activity coefficient, apparent potential, and diffusion coefficient of lanthanum, yttrium, scandium, and terbium in the molten salt (58 at% LiCl and 42 at% KCl) were calculated by the method of molecular dynamics simulation up to a concentration around 3 at% at temperatures of 723 K and 773 K. It was found that the activity coefficient and the apparent potential increase with the species concentration while diffusion coefficient shows a trend of increase followed by decrease. The calculated results were validated by available measurement data of dilution cases. This research extends the range of data to a wide component and would provide further insight to the pyroprocessing design and safeguards.

Electrochemical Formation of a p-n Junction on Thin Film Silicon Deposited in Molten Salt.

PubMed

Zou, Xingli; Ji, Li; Yang, Xiao; Lim, Taeho; Yu, Edward T; Bard, Allen J

2017-11-15

Herein we report the demonstration of electrochemical deposition of silicon p-n junctions all in molten salt. The results show that a dense robust silicon thin film with embedded junction formation can be produced directly from inexpensive silicates/silicon oxide precursors by a two-step electrodeposition process. The fabricated silicon p-n junction exhibits clear diode rectification behavior and photovoltaic effects, indicating promise for application in low-cost silicon thin film solar cells.

Electrical conductivity of KAlCl4-ZrCl4 molten mixtures

NASA Astrophysics Data System (ADS)

Salyulev, A. B.; Khokhlov, V. A.; Moskalenko, N. I.

2017-02-01

The electrical conductivity of commercially challenging KAlCl4-ZrCl4 molten mixtures has been studied as a function of temperature (in the range from 345°C to 500°C) and the ZrCl4 concentration (0‒32.5mol %) using cells of a unique design. It is found to vary in the range from 0.41 to 0.80 S cm-1, increasing with temperature or when the mole concentration of zirconium tetrachloride in molten mixtures decreases.

Mesoporous Hollow Ge Microspheres Prepared via Molten-Salt Metallothermic Reaction for High-Performance Li-Storage Anode.

PubMed

Lin, Ning; Li, Tieqiang; Han, Ying; Zhang, Qianliang; Xu, Tianjun; Qian, Yitai

2018-03-14

Generally, Ge-based anodes are prepared by metallothermic reduction of GeO 2 with Mg at 650 °C. Herein, a molten-salt system is developed a low-temperature metallothermic reduction of GeO 2 to prepare nanostructured Ge based anode materials. Typically, mesoporous hollow Ge microspheres are prepared by reduction of GeO 2 with metallic Mg in molten ZnCl 2 (mp 292) at 350 °C. Monodispersed Ge particles are synthesized through reduction of GeO 2 with Mg in molten AlCl 3 (mp 192 °C) at 250 °C. The meso-porous Ge anode delivers the reversible capacity of 1291 mA h g -1 at 0.2 C after 150 cycles with a retention of 97.3%, 1217 mA h g -1 at 0.8 C after 400 cycles with a retention of 91.9%, and superior rate capability with a capacity of 673 mA h g -1 even at 10 C. Then, the reaction mechanism and full-cell performance of as-prepared Ge anodes are studied systemically.

Electrochemical separation of uranium in the molten system LiF-NaF-KF-UF4

NASA Astrophysics Data System (ADS)

Korenko, M.; Straka, M.; Szatmáry, L.; Ambrová, M.; Uhlíř, J.

2013-09-01

This article is focused on the electrochemical investigation (cyclic voltammetry and related studies) of possible reduction of U4+ ions to metal uranium in the molten system LiF-NaF-KF(eut.)-UF4 that can provide basis for the electrochemical extraction of uranium from molten salts. Two-step reduction mechanism for U4+ ions involving one electron exchange in soluble/soluble U4+/U3+ system and three electrons exchange in the second step were found on the nickel working electrode. Both steps were found to be reversible and diffusion controlled. Based on cyclic voltammetry, the diffusion coefficients of uranium ions at 530 °C were found to be D(U4+) = 1.64 × 10-5 cm2 s-1 and D(U3+) 1.76 × 10-5 cm2 s-1. Usage of the nickel spiral electrode for electrorefining of uranium showed fairly good feasibility of its extraction. However some oxidant present during the process of electrorefining caused that the solid deposits contained different uranium species such as UF3, UO2 and K3UO2F5.

In Situ Solid-Gas Reactivity of Nanoscaled Metal Borides from Molten Salt Synthesis.

PubMed

Gouget, Guillaume; Debecker, Damien P; Kim, Ara; Olivieri, Giorgia; Gallet, Jean-Jacques; Bournel, Fabrice; Thomas, Cyril; Ersen, Ovidiu; Moldovan, Simona; Sanchez, Clément; Carenco, Sophie; Portehault, David

2017-08-07

Metal borides have mostly been studied as bulk materials. The nanoscale provides new opportunities to investigate the properties of these materials, e.g., nanoscale hardening and surface reactivity. Metal borides are often considered stable solids because of their covalent character, but little is known on their behavior under a reactive atmosphere, especially reductive gases. We use molten salt synthesis at 750 °C to provide cobalt monoboride (CoB) nanocrystals embedded in an amorphous layer of cobalt(II) and partially oxidized boron as a model platform to study morphological, chemical, and structural evolutions of the boride and the superficial layer exposed to argon, dihydrogen (H 2 ), and a mixture of H 2 and carbon dioxide (CO 2 ) through a multiscale in situ approach: environmental transmission electron microscopy, synchrotron-based near-ambient-pressure X-ray photoelectron spectroscopy, and near-edge X-ray absorption spectroscopy. Although the material is stable under argon, H 2 triggers at 400 °C decomposition of CoB, leading to cobalt(0) nanoparticles. We then show that H 2 activates CoB for the catalysis of CO 2 methanation. A similar decomposition process is also observed on NiB nanocrystals under oxidizing conditions at 300 °C. Our work highlights the instability under reactive atmospheres of nanocrystalline cobalt and nickel borides obtained from molten salt synthesis. Therefore, we question the general stability of metal borides with distinct compositions under such conditions. These results shed light on the actual species in metal boride catalysis and provide the framework for future applications of metal borides in their stability domains.

High temperature in-situ synchrotron-based XRD study on the crystal structure evolution of C/C composite impregnated by FLiNaK molten salt.

PubMed

Feng, Shanglei; Yang, Yingguo; Li, Li; Zhang, Dongsheng; Yang, Xinmei; Xia, Huihao; Yan, Long; Tsang, Derek K L; Huai, Ping; Zhou, Xingtai

2017-09-06

An in-situ real-time synchrotron-based grazing incidence X-ray diffraction was systematically used to investigate the crystal structural evolution of carbon fiber reinforced carbon matrix (C/C) composite impregnated with FLiNaK molten salt during the heat-treatment process. It was found that the crystallographic thermal expansion and contraction rate of interlayer spacing d 002 in C/C composite with FLiNaK salt impregnation is smaller than that in the virgin sample, indicating the suppression on interlayer spacing from FLiNaK salt impregnated. Meanwhile the crystallite size L C002 of C/C composite with FLiNaK salt impregnation is larger than the virgin one after whole heat treatment process, indicating that FLiNaK salt impregnation could facilitate the crystallization of C/C composite after heat treatment process. This improved crystallization in C/C composite with FLiNaK salt impregnation suggests the synthetic action of the salt squeeze effect on crooked carbon layer and the release of internal residual stress after heating-cooling process. Thus, the present study not only contribute to reveal the interaction mechanism between C/C composite and FLiNaK salt in high temperature environment, but also promote the design of safer and more reliable C/C composite materials for the next generation molten salt reactor.

Electrochemistry of actinides and fission products in molten salts-Data review

NASA Astrophysics Data System (ADS)

Zhang, Jinsuo

2014-04-01

The thermodynamic and electrochemical properties of actinides and fission products in the molten salt determine the pyroprocessing separation performance. Extensive measurements have been carried out to provide fundamental data for evaluating the separation efficiency and technology feasibility of pyroprocessing although the technology has been very well developed in laboratory. The state of the art of fundamental data for substance or materials involved in pyropocessing will be reviewed in the present article. The available data will be summarized and reanalyzed. New correlations, which extend the available data to a broad range of applications, will be developed based on available data from different measurements. Further research topics on providing fundamental data that is needed for scaling the current laboratory technology to industrial applications are identified.

Thermal Stability of FeS2 Cathode Material in "Thermal" Batteries: Effect of Dissolved Oxides in Molten Salt Electrolytes

NASA Astrophysics Data System (ADS)

Masset, Patrick J.

2008-09-01

The thermal stability of FeS2 cathode material for thermal batteries is investigated in the LiCl-KCl eutectic containing up to 10 wt% Li2O (used as anti-peak). The results show that the decomposition of pyrite shifts to higher temperatures in the presence of molten salts as the S2 gas is repressed by the liquid phase. For high lithium oxide contents the decomposition temperature of pyrite decreases by 100 °C. In addition Li2FeS2 as reaction product is evidenced whereas Li3Fe2S4 is expected from literature data.

Experimental results from a laboratory-scale molten salt thermocline storage

NASA Astrophysics Data System (ADS)

Seubert, Bernhard; Müller, Ralf; Willert, Daniel; Fluri, Thomas

2017-06-01

Single-tank storage presents a valid option for cost reduction in thermal energy storage systems. For low-temperature systems with water as storage medium this concept is widely implemented and tested. For high-temperature systems very limited experimental data are publicly available. To improve this situation a molten salt loop for experimental testing of a single-tank storage prototype was designed and built at Fraunhofer ISE. The storage tank has a volume of 0.4 m3 or a maximum capacity of 72 kWhth. The maximum charging and discharging power is 60 kW, however, a bypass flow control system enables to operate the system also at a very low power. The prototype was designed to withstand temperatures up to 550 °C. A cascaded insulation with embedded heating cables can be used to reduce the effect of heat loss on the storage which is susceptible to edge effects due to its small size. During the first tests the operating temperatures were adapted to the conditions in systems with thermal oil as heat transfer fluid and a smaller temperature difference. A good separation between cold and hot fluid was achieved with temperature gradients of 95 K within 16 cm.

Impact of thorium based molten salt reactor on the closure of the nuclear fuel cycle

NASA Astrophysics Data System (ADS)

Jaradat, Safwan Qasim Mohammad

Molten salt reactor (MSR) is one of six reactors selected by the Generation IV International Forum (GIF). The liquid fluoride thorium reactor (LFTR) is a MSR concept based on thorium fuel cycle. LFTR uses liquid fluoride salts as a nuclear fuel. It uses 232Th and 233U as the fertile and fissile materials, respectively. Fluoride salt of these nuclides is dissolved in a mixed carrier salt of lithium and beryllium (FLiBe). The objective of this research was to complete feasibility studies of a small commercial thermal LFTR. The focus was on neutronic calculations in order to prescribe core design parameter such as core size, fuel block pitch (p), fuel channel radius, fuel path, reflector thickness, fuel salt composition, and power. In order to achieve this objective, the applicability of Monte Carlo N-Particle Transport Code (MCNP) to MSR modeling was verified. Then, a prescription for conceptual small thermal reactor LFTR and relevant calculations were performed using MCNP to determine the main neutronic parameters of the core reactor. The MCNP code was used to study the reactor physics characteristics for the FUJI-U3 reactor. The results were then compared with the results obtained from the original FUJI-U3 using the reactor physics code SRAC95 and the burnup analysis code ORIPHY2. The results were comparable with each other. Based on the results, MCNP was found to be a reliable code to model a small thermal LFTR and study all the related reactor physics characteristics. The results of this study were promising and successful in demonstrating a prefatory small commercial LFTR design. The outcome of using a small core reactor with a diameter/height of 280/260 cm that would operate for more than five years at a power level of 150 MWth was studied. The fuel system 7LiF - BeF2 - ThF4 - UF4 with a (233U/ 232Th) = 2.01 % was the candidate fuel for this reactor core.

Dynamic modelling and simulation of linear Fresnel solar field model based on molten salt heat transfer fluid

NASA Astrophysics Data System (ADS)

Hakkarainen, Elina; Tähtinen, Matti

2016-05-01

Demonstrations of direct steam generation (DSG) in linear Fresnel collectors (LFC) have given promising results related to higher steam parameters compared to the current state-of-the-art parabolic trough collector (PTC) technology using oil as heat transfer fluid (HTF). However, DSG technology lacks feasible solution for long-term thermal energy storage (TES) system. This option is important for CSP technology in order to offer dispatchable power. Recently, molten salts have been proposed to be used as HTF and directly as storage medium in both line-focusing solar fields, offering storage capacity of several hours. This direct molten salt (DMS) storage concept has already gained operational experience in solar tower power plant, and it is under demonstration phase both in the case of LFC and PTC systems. Dynamic simulation programs offer a valuable effort for design and optimization of solar power plants. In this work, APROS dynamic simulation program is used to model a DMS linear Fresnel solar field with two-tank TES system, and example simulation results are presented in order to verify the functionality of the model and capability of APROS for CSP modelling and simulation.

Determination of activity coefficient of lanthanum chloride in molten LiCl-KCl eutectic salt as a function of cesium chloride and lanthanum chloride concentrations using electromotive force measurements

NASA Astrophysics Data System (ADS)

Bagri, Prashant; Simpson, Michael F.

2016-12-01

The thermodynamic behavior of lanthanides in molten salt systems is of significant scientific interest for the spent fuel reprocessing of Generation IV reactors. In this study, the apparent standard reduction potential (apparent potential) and activity coefficient of LaCl3 were determined in a molten salt solution of eutectic LiCl-KCl as a function of concentration of LaCl3. The effect of adding up to 1.40 mol % CsCl was also investigated. These properties were determined by measuring the open circuit potential of the La-La(III) redox couple in a high temperature molten salt electrochemical cell. Both the apparent potential and activity coefficient exhibited a strong dependence on concentration. A low concentration (0.69 mol %) of CsCl had no significant effect on the measured properties, while a higher concentration (1.40 mol %) of CsCl caused an increase (become more positive) in the apparent potential and activity coefficient at the higher range of LaCl3 concentrations.

Synthesis of Nano Sized Cr2AlC Powders by Molten Salt Method.

PubMed

Xiao, Dan; Zhu, Jianfeng; Wang, Fen; Tang, Yi

2015-09-01

Cr2AlC powders were successfully synthesized by molten salt method using Cr, Al and C as starting materials. The effects of the process parameters and amount of Al addition on the purity of the Cr2AlC powders were also investigated in details. The formation mechanism of Cr2AlC powders was investigated by XRD and DSC. The results indicated that intermediates of Cr7C3 and Cr- Al intermetallics, such as CrAl17, Cr2Al, Cr2Al8, were formed by the reactions among the initial elements, then the intermediates gradually transformed to Cr2AlC. From the fixed composition of Cr:Al:C = 2:1.2:1, high purity Cr2AlC powders could be obtained with an inorganic salt KCl as a solvent at 1250 degrees C for 60 min under argon atmosphere which was lower than that (generally 1450 degrees C) of conventional solid state reaction.

Absorption characteristics of anions (I-, Br-, and Te2-) into zeolite in molten LiCl-KCl eutectic salt

NASA Astrophysics Data System (ADS)

Uozumi, Koichi; Sugihara, Kei; Kinoshita, Kensuke; Koyama, Tadafumi; Tsukada, Takeshi; Terai, Takayuki; Suzuki, Akihiro

2014-04-01

The behaviors of anion fission product (FP) elements to be absorbed into zeolite in molten LiCl-KCl eutectic salt were studied using iodine, bromine, and tellurium. First, the type-A zeolite was selected as the most suitable type of zeolite among type-A, type-X, and type-Y zeolites through experiments in which zeolites were heated together with LiCl-KCl-KI salt. As the next step, experiments in which the type-A zeolite was immersed in molten LiCl-KCl salt containing various concentrations of iodine, bromine, or tellurium were performed. The degree of absorption of the anion FP elements was evaluated using the separation factor (SF) value versus chlorine. Although the SF values for iodine and tellurium were higher than 1.0, which meant that these elements were absorbed into the type-A zeolite more intensively than chlorine in the salt, the corresponding value for bromine was approximately 1.0. The effects of coexisting cation FPs were also examined using cesium, strontium, and neodymium, and it was revealed that the SF values for iodine were less than those in the case without cation addition. On the other hand, the SF values for tellurium were not affected by the coexistence of cesium and strontium. Finally, the feasibility of the present pyroprocess flowsheet was evaluated by calculating the inventory of each anion FP in an electrorefiner based on the obtained SF values instead of temporary values for the anion FPs absorption, which were set due to lack of experimental data.

Rechargeable Al/Cl2 battery with molten AlCl4/-/ electrolyte.

NASA Technical Reports Server (NTRS)

Holleck, G. L.; Giner, J.; Burrows, B.

1972-01-01

A molten salt system based on Al- and Cl2 carbon electrodes, with an AlCl3 alkali chloride eutectic as electrolyte, offers promise as a rechargeable, high energy density battery which can operate at a relatively low temperature. Electrode kinetic studies showed that the electrode reactions at the Al anode were rapid and that the observed passivation phenomena were due to the formation at the electrode surface of a solid salt layer resulting from concentration changes on anodic or cathodic current flow. It was established that carbon electrodes were intrinsically active for chlorine reduction in AlCl3-alkali chloride melts. By means of a rotating vitreous carbon disk electrode, the kinetic parameters were determined.

Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

DOEpatents

Maroni, V.A.; von Winbush, S.

1987-05-01

A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500/degree/C, electrolysis at a voltage not more negative that about /minus/1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

DOEpatents

Maroni, Victor A.; von Winbush, Samuel

1988-01-01

A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500.degree. C., electrolysis at a voltage not more negative than about -1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

Optimized molten salt receivers for ultimate trough solar fields

NASA Astrophysics Data System (ADS)

Riffelmann, Klaus-J.; Richert, Timo; Kuckelkorn, Thomas

2016-05-01

Today parabolic trough collectors are the most successful concentrating solar power (CSP) technology. For the next development step new systems with increased operation temperature and new heat transfer fluids (HTF) are currently developed. Although the first power tower projects have successfully been realized, up to now there is no evidence of an all-dominant economic or technical advantage of power tower or parabolic trough. The development of parabolic trough technology towards higher performance and significant cost reduction have led to significant improvements in competitiveness. The use of molten salt instead of synthetic oil as heat transfer fluid will bring down the levelized costs of electricity (LCOE) even further while providing dispatchable energy with high capacity factors. FLABEG has developed the Ultimate TroughTM (UT) collector, jointly with sbp Sonne GmbH and supported by public funds. Due to its validated high optical accuracy, the collector is very suitable to operate efficiently at elevated temperatures up to 550 °C. SCHOTT will drive the key-innovations by introducing the 4th generation solar receiver that addresses the most significant performance and cost improvement measures. The new receivers have been completely redesigned to provide a product platform that is ready for high temperature operation up to 550 °C. Moreover distinct product features have been introduced to reduce costs and risks in solar field assembly and installation. The increased material and design challenges incurred with the high temperature operation have been reflected in sophisticated qualification and validation procedures.

Ultraviolet and infrared spectroscopy for effluent analysis in a molten salt electrochemical cell

NASA Astrophysics Data System (ADS)

Moore, J. F.; Pellin, M. J.; Calaway, W. F.; Hryn, J. N.

2003-08-01

An apparatus that combines gas phase spectroscopy over two wavelength ranges for analysis of effluent from a molten salt electrochemical cell is described. The cell is placed in a quartz tube that is sealed at the top with a cap containing feedthrus for power, thermometry, and gas flow. A resistance furnace brings the cell assembly to the desired temperature while the cap remains cooled by water. Inert gas continually purges the cell headspace carrying effluent from the electrolysis sequentially through two gas cells, one in a Fourier transform infrared (FTIR) spectrometer and one in a fiber-optic coupled ultraviolet visible spectrometer. Strong vibrational absorptions in the IR can easily identify common effluent components such as HCl, CO, CO2, and H2O. Electronic bands can identify IR-inactive molecules of importance including Cl2 and O2. Since the absorptivity of all of these species is known, determinations of the gas concentration can be made without using standards. Spectra from the electrolysis of molten MgCl2 are shown and discussed, as well as the limit of detection and inherent time resolution of the apparatus as implemented.

A novel process for recovery of iron, titanium, and vanadium from titanomagnetite concentrates: NaOH molten salt roasting and water leaching processes.

PubMed

Chen, Desheng; Zhao, Longsheng; Liu, Yahui; Qi, Tao; Wang, Jianchong; Wang, Lina

2013-01-15

A novel process for recovering iron, titanium, and vanadium from titanomagnetite concentrates has been developed. In the present paper, the treatment of rich titanium-vanadium slag by NaOH molten salt roasting and water leaching processes is investigated. In the NaOH molten salt roasting process, the metallic iron is oxidized into ferriferous oxide, MgTi(2)O(5) is converted to NaCl-type structure of Na(2)TiO(3), and M(3)O(5) (M=Ti, Mg, Fe) is converted to α-NaFeO(2)-type structure of NaMO(2), respectively. Roasting temperature and NaOH-slag mass ratio played a considerable role in the conversion of titanium in the rich titanium-vanadium slag during the NaOH molten salt roasting process. Roasting at 500 °C for 60 min and a 1:1 NaOH-slag mass ratio produces 96.3% titanium conversion. In the water leaching process, the Na(+) was exchanged with H(+), Na(2)TiO(3) is converted to undefined structure of H(2)TiO(3), and NaMO(2) is converted to α-NaFeO(2)-type structure of HMO(2). Under the optimal conditions, 87.3% of the sodium, 42.3% of the silicon, 43.2% of the aluminum, 22.8% of the manganese, and 96.6% of the vanadium are leached out. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Molten salt synthesis, visible and near-IR region spectral properties of europium or neodymium doped CoNb2O6 columbite niobate.

PubMed

Ekmekçi, Mete Kaan; Erdem, Murat; Başak, Ali Sadi

2015-03-28

Pure Nd(3+)- or Eu(3+)-doped CoNb2O6 powders have been prepared by a molten salt synthesis method using a Li2SO4-Na2SO4 or NaCl-KCl salt mixture as a flux at relatively low temperatures as compared to the solid state reaction method. X-ray diffraction patterns of pure CoNb2O6 samples indicated an orthorhombic single phase. For Eu(3+)-doped CoNb2O6 samples, the luminescence of Eu(3+) was observed at 615 nm as red emission while the Nd(3+) doped sample showed a typical emission at 1064 nm varying with the Eu(3+) or Nd(3+) doping concentrations. These luminescence characteristics of the doped samples may be attributed to the energy transfer between rare earth ions and CoO6 octahedral groups in the columbite structure.

Impact of corrosion test container material in molten fluorides

DOE PAGES

Olson, Luke C.; Fuentes, Roderick E.; Martinez-Rodriguez, Michael J.; ...

2015-10-15

The effects of crucible material choice on alloy corrosion rates in immersion tests in molten LiF–NaF–KF (46.5–11.5-42 mol. %) salt held at 850 °C for 500 hrs are described. Four crucible materials were studied. Molten salt exposures of Incoloy-800H in graphite, Ni, Incoloy-800H, and pyrolytic boron nitride (PyBN) crucibles all led to weight-loss in the Incoloy-800H coupons. Alloy weight loss was ~30 times higher in the graphite and Ni crucibles in comparison to the Incoloy-800H and PyBN crucibles. It is hypothesized galvanic coupling between the alloy coupons and crucible materials contributed to the higher corrosion rates. Alloy salt immersion inmore » graphite and Ni crucibles had similar weight-loss hypothesized to occur due to the rate limiting out diffusion of Cr in the alloys to the surface where it reacts with and dissolves into the molten salt, followed by the reduction of Cr from solution at the molten salt and graphite/Ni interfaces. As a result, both the graphite and the Ni crucibles provided sinks for the Cr, in the formation of a Ni–Cr alloy in the case of the Ni crucible, and Cr carbide in the case of the graphite crucible.« less

The results of the investigations of Russian Research Center - {open_quotes}Kurchatov Institute{close_quotes} on molten salt applications to problems of nuclear energy systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Novikov, V.M.

1995-10-01

The results of investigations on molten salt (MS) applications to problems of nuclear energy systems that have been conducted in Russian Research {open_quotes}Kurchatov Institute{close_quotes} are presented and discussed. The spectrum of these investigations is rather broad and covers the following items: physical characteristics of molten salt nuclear energy systems (MSNES); nuclear and radiation safety of MSNES; construction materials compatible with MS of different compositions; technological aspects of MS loops; in-reactor loop testing. It is shown that main findings of completed program support the conclusion that there are no physical nor technological obstacles on way of MS application to different nuclearmore » energy systems.« less

Microporous carbons derived from melamine and isophthalaldehyde: One-pot condensation and activation in a molten salt medium for efficient gas adsorption.

PubMed

Rehman, Adeela; Park, Soo-Jin

2018-04-17

In the present work, mixture of melamine and isophthalaldehyde undergo simultaneous polymerization, carbonization, and in situ activation in the presence of molten salt media through a single all-in-one route to design microporous carbons with high specific surface areas (~3000 m 2 /g). The effect of the activation temperature and molten salts on the polymerization process and final texture of the carbon was explored. Carbon materials prepared at 700 °C, in the presence of KOH (referred as MIK-700), exhibited a narrower pore-size distribution ~1.05 nm than those prepared in the presence of the eutectic KOH-NaOH mixture (MIKN). Additionally, MIK-700 possesses an optimum micropore volume (1.33 cm 3 /g) along with a high nitrogen content (2.66 wt%), resulting in the excellent CO 2 adsorption capacity of 9.7 mmol/g at 273 K and 1 bar. Similarly, the high specific area and highest total pore volume play an important role in H 2 storage at 77 K, with 4.0 wt% uptake by MIKN-800 (specific surface area and pore volume of 2984 m 2 /g and 1.98 cm 3 /g, respectively.) Thus, the facile one-step solvent-free synthesis and activation strategy is an economically favorable avenue for designing microporous carbons as an efficient gas adsorbents.

Renewable and high efficient syngas production from carbon dioxide and water through solar energy assisted electrolysis in eutectic molten salts

NASA Astrophysics Data System (ADS)

Wu, Hongjun; Liu, Yue; Ji, Deqiang; Li, Zhida; Yi, Guanlin; Yuan, Dandan; Wang, Baohui; Zhang, Zhonghai; Wang, Peng

2017-09-01

Over-reliance on non-renewable fossil fuel leads to steadily increasing concentration of atmospheric CO2, which has been implicated as a critical factor contributing to global warming. The efficient conversion of CO2 into useful product is highly sought after both in academic and industry. Herein, a novel conversion strategy is proposed to one-step transform CO2/H2O into syngas (CO/H2) in molten salt with electrolysis method. All the energy consumption in this system are contributed from sustainable energy sources: concentrated solar light heats molten salt and solar cell supplies electricity for electrolysis. The eutectic Li0.85Na0.61K0.54CO3/nLiOH molten electrolyte is rationally designed with low melting point (<450 °C). The synthesized syngas contains very desirable content of H2 and CO, with tuneable molar ratios (H2/CO) from 0.6 to 7.8, and with an efficient faradaic efficiency of ∼94.5%. The synthesis of syngas from CO2 with renewable energy at a such low electrolytic temperature not only alleviates heat loss, mitigates system corrosion, and heightens operational safety, but also decreases the generation of methane, thus increases the yield of syngas, which is a remarkable technological breakthrough and this work thus represents a stride in sustainable conversion of CO2 to value-added product.

Equilibrium distribution of rare earth elements between molten KCl-LiCl eutectic salt and liquid cadmium

NASA Astrophysics Data System (ADS)

Sakata, Masahiro; Kurata, Masaki; Hijikata, Takatoshi; Inoue, Tadashi

1991-11-01

Distribution experiments for several rare earth elements (La, Ce, Pr, Nd and Y) between molten KCl-LiCl eutectic salt and liquid Cd were carried out at 450, 500 and 600°C. The material balance of rare earth elements after reaching the equilibrium and their distribution and chemical states in a Cd sample frozen after the experiment were examined. The results suggested the formation of solid intermetallic compounds at the lower concentrations of rare earth metals dissolved in liquid Cd than those solubilities measured in the binary alloy system. The distribution coefficients of rare earth elements between two phases (mole fraction in the Cd phase divided by mole fraction in the salt phase) were determined at each temperature. These distribution coefficients were explained satisfactorily by using the activity coefficients of chlorides and metals in salt and Cd. Both the activity coefficients of metal and chloride caused a much smaller distribution coefficient of Y relative to those of other elements.

Preliminary analysis of the PreFlexMS molten salt once-through steam generator dynamics and control strategy

NASA Astrophysics Data System (ADS)

Trabucchi, Stefano; Casella, Francesco; Maioli, Tommaso; Elsido, Cristina; Franzini, Davide; Ramond, Mathieu

2017-06-01

Concentrated Solar Power plants (CSP) coupled with thermal storage have the potential to guarantee both flexible and continuous energy production, thus being competitive with conventional fossil fuel and hydro power plants, in terms of dispatchability and provision of ancillary services. Hence, the plant equipment and control design have to be focused on flexible operation on one hand, and on plant safety concerning the molten salt freezing on the other hand. The PreFlexMS European project aims to introduce a molten salt Once-Through Steam Generator (OTSG) within a Rankine cycle based power unit, a technology that has greater flexibility potential if compared to steam drum boilers, currently used in CSP plants. The dynamic modelling and simulation from the early design stages is, thus, of paramount importance, to assess the plant dynamic behavior and controllability, and to predict the achievable closed-loop dynamic performance, potentially saving money and time during the detailed design, construction and commissioning phases. The present paper reports the main results of the analysis carried out during the first part of the project, regarding the system analysis and control design. In particular, two different control systems have been studied and tested with the plant dynamic model: a decentralized control strategy based on PI controllers and a Linear Model Predictive Control (LMPC).

Production of Titanium Metal by an Electrochemical Molten Salt Process

NASA Astrophysics Data System (ADS)

Fatollahi-Fard, Farzin

Titanium production is a long and complicated process. What we often consider to be the standard method of primary titanium production (the Kroll process), involves many complex steps both before and after to make a useful product from titanium ore. Thus new methods of titanium production, especially electrochemical processes, which can utilize less-processed feedstocks have the potential to be both cheaper and less energy intensive than current titanium production processes. This project is investigating the use of lower-grade titanium ores with the electrochemical MER process for making titanium via a molten salt process. The experimental work carried out has investigated making the MER process feedstock (titanium oxycarbide) with natural titanium ores--such as rutile and ilmenite--and new ways of using the MER electrochemical reactor to "upgrade" titanium ores or the titanium oxycarbide feedstock. It is feasible to use the existing MER electrochemical reactor to both purify the titanium oxycarbide feedstock and produce titanium metal.

Molten Salt Electrolytically Produced Carbon/Tin Nanomaterial as the Anode in a Lithium Ion Battery

NASA Astrophysics Data System (ADS)

Das Gupta, Rajshekar; Schwandt, Carsten; Fray, Derek J.

2017-03-01

A carbon/tin nanomaterial, consisting of predominantly Sn-filled carbon nanotubes and nanoparticles, is prepared by molten salt electrochemistry, using electrodes of graphite and an electrolyte of LiCl salt containing a small admixture of SnCl2. The C/Sn hybrid material generated is incorporated into the active anode material of a lithium ion battery and tested with regard to storage capacity and cycling behavior. The results demonstrate that the C/Sn material has favorable properties, in terms of energy density and in particular long-term stability, that exceed those of the individual components alone. The initial irreversible capacity of the material is somewhat larger than that of conventional battery graphite which is due to its unique nanostructure. Overall the results would indicate the suitability of this material for use in the anodes of lithium ion batteries with high rate capability.

Molten salt corrosion of SiC and Si3N4

NASA Technical Reports Server (NTRS)

Jacobson, N. S.; Smialek, J. L.; Fox, D. S.

1986-01-01

The most severe type of corrosion encountered in heat engines is corrosion by molten sodium sulfate, formed by the reaction of ingested sodium chloride and sulfur impurities in the fuel. This problem was studied extensively for superalloys, but only recently examined for ceramics. This problem is addressed with laboratory studies to understand the fundamental reaction mechanisms and with burner studies to provide a more realistic simulation of the conditions encountered in a heat engine. In addition the effect of corrosion on the strengths of these materials was assessed. Each of these aspects will be reviewed and some ideas toward possible solutions will be discussed.

Properties and heat transfer coefficients of four molten-salt high temperature heat transfer fluid candidates for concentrating solar power plants

NASA Astrophysics Data System (ADS)

Liu, T. L.; Liu, W. R.; Xu, X. H.

2017-11-01

Heat transfer fluid is one critical component for transferring and storing heat energy in concentrating solar power systems. Molten-salt mixtures can be used as high temperature heat transfer fluids because of their thermophysical properties. This paper studied the thermophysical properties of Li2CO3-Na2CO3-K2CO3 eutectic salt and three eutectic chloride salts NaCl-KCl-ZnCl2 with different compositions in the range of 450-600°C and 250-800°C, respectively. Properties including specific heat capacity, thermal conductivity, density and viscosity were determined based on imperial correlations and compared at different operating temperatures. The heat transfer coefficients of using different eutectic salts as heat transfer fluids were also calculated and compared in their operating temperature range. It is concluded that all the four eutectic salts can satisfy the requirements of a high-temperature heat transfer fluid.

Hot corrosion behavior of YSZ, Gd2Zr2O7 and YSZ/Gd2Zr2O7 thermal barrier coatings exposed to molten sulfate and vanadate salt

NASA Astrophysics Data System (ADS)

Ozgurluk, Yasin; Doleker, Kadir Mert; Karaoglanli, Abdullah Cahit

2018-04-01

Thermal barrier coatings (TBCs) are mostly used in critical components of aircraft gas turbine engines. Hot corrosion is among the main deteriorating factors in TBCs which results from the effect of molten salt on the coating-gas interface. This type of corrosion is observed as a result of contamination accumulated during combustion processes. Fuels used in aviation industry generally contain impurities such as vanadium oxide (V2O5) and sodium sulfate (Na2SO4). These impurities damage turbines' inlet at elevated temperatures because of chemical reaction. Yttria stabilized zirconia (YSZ) is a conventional top coating material for TBCs while Gd2Zr2O7 is a new promising top coating material for TBCs. In this study, CoNiCrAlY metallic bond coat was deposited on Inconel 718 nickel based superalloy substrate material with a thickness about 100 μm using cold gas dynamic spray (CGDS) method. Production of TBCs were done with deposition of YSZ, Gd2Zr2O7, YSZ/Gd2Zr2O7 ceramic top coating materials using EB-PVD method, having a total thickness of 300 μm. Hot corrosion behavior of YSZ, Gd2Zr2O7, YSZ/Gd2Zr2O7 TBC systems were exposed to 45 wt.% Na2SO4 and 55 wt.% V2O5 molten salt mixtures at 1000 °C temperature. TBC samples were investigated and compared using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) analysis and X-ray diffractometer (XRD). The hot corrosion failure mechanisms of YSZ, Gd2Zr2O7 and YSZ/Gd2Zr2O7 TBCs in the molten salts were evaluated.

A Tunable Molten-Salt Route for Scalable Synthesis of Ultrathin Amorphous Carbon Nanosheets as High-Performance Anode Materials for Lithium-Ion Batteries.

PubMed

Wang, Yixian; Tian, Wei; Wang, Luhai; Zhang, Haoran; Liu, Jialiang; Peng, Tingyue; Pan, Lei; Wang, Xiaobo; Wu, Mingbo

2018-02-14

Amorphous carbon is regarded as a promising alternative to commercial graphite as the lithium-ion battery anode due to its capability to reversibly store more lithium ions. However, the structural disorder with a large number of defects can lead to low electrical conductivity of the amorphous carbon, thus limiting its application for high power output. Herein, ultrathin amorphous carbon nanosheets were prepared from petroleum asphalt through tuning the carbonization temperature in a molten-salt medium. The amorphous nanostructure with expanded carbon interlayer spacing can provide substantial active sites for lithium storage, while the two-dimensional (2D) morphology can facilitate fast electrical conductivity. As a result, the electrodes deliver a high reversible capacity, outstanding rate capability, and superior cycling performance (579 and 396 mAh g -1 at 2 and 5 A g -1 after 900 cycles). Furthermore, full cells consisting of the carbon anodes coupled with LiMn 2 O 4 cathodes exhibit high specific capacity (608 mAh g -1 at 50 mA g -1 ) and impressive cycling stability with slow capacity loss (0.16% per cycle at 200 mA g -1 ). The present study not only paves the way for industrial-scale synthesis of advanced carbon materials for lithium-ion batteries but also deepens the fundamental understanding of the intrinsic mechanism of the molten-salt method.

Multicomponent diffusion in molten salt NaF-ZrF4: Dynamical correlations and Maxwell-Stefan diffusivities

NASA Astrophysics Data System (ADS)

Baig, Mohammad Saad; Chakraborty, Brahmananda; Ramaniah, Lavanya M.

2016-05-01

NaF-ZrF4 is used as a waste incinerator and as a coolant in Generation IV reactors.Structural and dynamical properties of molten NaF-ZrF4 system were studied along with Onsagercoefficients and Maxwell-Stefan (MS) Diffusivities applying Green-Kubo formalism and molecular dynamics (MD) simulations. The zirconium ions are found to be 8 fold coordinated with fluoride ions for all temperatures and concentrations. All the diffusive flux correlations show back-scattering. Even though the MS diffusivities are expected to depend very lightly on the composition because of decoupling of thermodynamic factor, the diffusivity ĐNa-F shows interesting behavior with the increase in concentration of ZrF4. This is because of network formation in NaF-ZrF4. Positive entropy constraints have been plotted to authenticate negative diffusivities observed.

Molten Metal Treatment by Salt Fluxing with Low Environmental Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yogeshwar Sahai

2007-07-31

Abstract: Chlorine gas is traditionally used for fluxing of aluminum melt for removal of alkali and alkaline earth elements. However this results in undesirable emissions of particulate matter and gases such as HCl and chlorine, which are often at unacceptable levels. Additionally, chlorine gas is highly toxic and its handling, storage, and use pose risks to employees and the local community. Holding of even minimal amounts of chlorine necessitates extensive training for all plant employees. Fugitive emissions from chlorine usage within the plant cause accelerated corrosion of plant equipment. The Secondary Aluminum Maximum Achievable Control Technology (MACT) under the Cleanmore » Air Act, finalized in March 2000 has set very tough new limits on particulate matter (PM) and total hydrogen chloride emissions from aluminum melting and holding furnaces. These limits are 0.4 and 0.1 lbs per ton of aluminum for hydrogen chloride and particulate emissions, respectively. Assuming new technologies for meeting these limits can be found, additional requirements under the Clean Air Act (Prevention of Significant Deterioration and New Source Review) trigger Best Available Control Technology (BACT) for new sources with annual emissions (net emissions not expressed per ton of production) over specified amounts. BACT currently is lime coated bag-houses for control of particulate and HCl emissions. These controls are expensive, difficult to operate and maintain, and result in reduced American competitiveness in the global economy. Solid salt fluxing is emerging as a viable option for the replacement of chlorine gas fluxing, provided emissions can be consistently maintained below the required levels. This project was a cooperative effort between the Ohio State University and Alcoa to investigate and optimize the effects of solid chloride flux addition in molten metal for alkali impurity and non-metallic inclusion removal minimizing dust and toxic emissions and maximizing energy

Coupled neutronics and thermal-hydraulics numerical simulations of a Molten Fast Salt Reactor (MFSR)

NASA Astrophysics Data System (ADS)

Laureau, A.; Rubiolo, P. R.; Heuer, D.; Merle-Lucotte, E.; Brovchenko, M.

2014-06-01

Coupled neutronics and thermalhydraulic numerical analyses of a molten salt fast reactor are presented. These preliminary numerical simulations are carried-out using the Monte Carlo code MCNP and the Computation Fluid Dynamic code OpenFOAM. The main objectives of this analysis performed at steady-reactor conditions are to confirm the acceptability of the current neutronic and thermalhydraulic designs of the reactor, to study the effects of the reactor operating conditions on some of the key MSFR design parameters such as the temperature peaking factor. The effects of the precursor's motion on the reactor safety parameters such as the effective fraction of delayed neutrons have been evaluated.

Molten salt rolling bubble column, reactors utilizing same and related methods

DOEpatents

Turner, Terry D.; Benefiel, Bradley C.; Bingham, Dennis N.; Klinger, Kerry M.; Wilding, Bruce M.

2015-11-17

Reactors for carrying out a chemical reaction, as well as related components, systems and methods are provided. In accordance with one embodiment, a reactor is provided that includes a furnace and a crucible positioned for heating by the furnace. The crucible may contain a molten salt bath. A downtube is disposed at least partially within the interior crucible along an axis. The downtube includes a conduit having a first end in communication with a carbon source and an outlet at a second end of the conduit for introducing the carbon material into the crucible. At least one opening is formed in the conduit between the first end and the second end to enable circulation of reaction components contained within the crucible through the conduit. An oxidizing material may be introduced through a bottom portion of the crucible in the form of gas bubbles to react with the other materials.

Testing Metal Chlorides For Use In Sodium-Cell Cathodes

NASA Technical Reports Server (NTRS)

Bugga, Ratnakumar V.; Attia, Alan I.; Halpert, Gerald

1992-01-01

Cyclic voltammetric curves of transition-metal wires in molten NaAlCl4 electrolyte used to eliminate suitability of transition metals as cathodes in sodium cells. Cyclic voltammetry used in conjunction with measurement of galvanostatic polarization curves determines whether given metal chloride suitable as cathode material in such cell. Cells useful in such high-energy-density and high-power-density applications as leveling loads on electric-power plants, supplying power to electric ground vehicles, and aerospace applications.

A furnace and environmental cell for the in situ investigation of molten salt electrolysis using high-energy X-ray diffraction.

PubMed

Styles, Mark J; Rowles, Matthew R; Madsen, Ian C; McGregor, Katherine; Urban, Andrew J; Snook, Graeme A; Scarlett, Nicola V Y; Riley, Daniel P

2012-01-01

This paper describes the design, construction and implementation of a relatively large controlled-atmosphere cell and furnace arrangement. The purpose of this equipment is to facilitate the in situ characterization of materials used in molten salt electrowinning cells, using high-energy X-ray scattering techniques such as synchrotron-based energy-dispersive X-ray diffraction. The applicability of this equipment is demonstrated by quantitative measurements of the phase composition of a model inert anode material, which were taken during an in situ study of an operational Fray-Farthing-Chen Cambridge electrowinning cell, featuring molten CaCl(2) as the electrolyte. The feasibility of adapting the cell design to investigate materials in other high-temperature environments is also discussed.

Toward Cost-Effective Manufacturing of Silicon Solar Cells: Electrodeposition of High-Quality Si Films in a CaCl2 -based Molten Salt.

PubMed

Yang, Xiao; Ji, Li; Zou, Xingli; Lim, Taeho; Zhao, Ji; Yu, Edward T; Bard, Allen J

2017-11-20

Electrodeposition of Si films from a Si-containing electrolyte is a cost-effective approach for the manufacturing of solar cells. Proposals relying on fluoride-based molten salts have suffered from low product quality due to difficulties in impurity control. Here we demonstrate the successful electrodeposition of high-quality Si films from a CaCl 2 -based molten salt. Soluble Si IV -O anions generated from solid SiO 2 are electrodeposited onto a graphite substrate to form a dense film of crystalline Si. Impurities in the deposited Si film are controlled at low concentrations (both B and P are less than 1 ppm). In the photoelectrochemical measurements, the film shows p-type semiconductor character and large photocurrent. A p-n junction fabricated from the deposited Si film exhibits clear photovoltaic effects. This study represents the first step to the ultimate goal of developing a cost-effective manufacturing process for Si solar cells based on electrodeposition. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diffusion mechanism in molten salt baths during the production of carbide coatings via thermal reactive diffusion

NASA Astrophysics Data System (ADS)

Ghadi, Aliakbar; Saghafian, Hassan; Soltanieh, Mansour; Yang, Zhi-gang

2017-12-01

The diffusion mechanism of carbide-forming elements from a molten salt bath to a substrate surface was studied in this research, with particular focus on the processes occurring in the molten bath at the time of coating. Metal, oxide, and metal-oxide baths were investigated, and the coating process was performed on H13 steel substrates. Scanning electron microscopy and electron-probe microanalysis were used to study the coated samples and the quenched salt bath. The thickness of the carbide coating layer was 6.5 ± 0.5, 5.2 ± 0.5, or 5.7 ± 0.5 μm depending on whether it was deposited in a metal, oxide, or metal-oxide bath, respectively. The phase distribution of vanadium-rich regions was 63%, 57%, and 74% of the total coating deposited in metal, oxide, and metal-oxide baths, respectively. The results obtained using the metal bath indicated that undissolved suspended metal particles deposited onto the substrate surface. Then, carbon subsequently diffused to the substrate surface and reacted with the metal particles to form the carbides. In the oxide bath, oxide powders dissolved in the bath with or without binding to the oxidative structure (Na2O) of borax; they were then reduced by aluminum and converted into metal particles. We concluded that, in the metal and oxide baths, the deposition of metal particles onto the sample surface is an important step in the formation of the coating.

Activation energy-activation volume master plots for ion transport behavior in polymer electrolytes and supercooled molten salts.

PubMed

Ingram, Malcolm D; Imrie, Corrie T; Stoeva, Zlatka; Pas, Steven J; Funke, Klaus; Chandler, Howard W

2005-09-08

We demonstrate the use of activation energy versus activation volume "master plots" to explore ion transport in typical fragile glass forming systems exhibiting non-Arrhenius behavior. These systems include solvent-free salt complexes in poly(ethylene oxide) (PEO) and low molecular weight poly(propylene oxide) (PPO) and molten 2Ca(NO3)2.3KNO3 (CKN). Plots showing variations in apparent activation energy EA versus apparent activation volume VA are straight lines with slopes given by M = DeltaEA/DeltaVA. A simple ion transport mechanism is described where the rate determining step involves a dilatation (expressed as VA) around microscopic cavities and a corresponding work of expansion (EA). The slopes of the master plots M are equated to internal elastic moduli, which vary from 1.1 GPa for liquid PPO to 5.0 GPa for molten CKN on account of differing intermolecular forces in these materials.

Electrochemical performance of LiNi0.4Co0.2Mn0.4O2 prepared by different molten salt flux: LiNO3-LiCl and LiNO3-KNO3

NASA Astrophysics Data System (ADS)

Satyanarayana, M.; James, Joseph; U. V., Varadaraju

2017-10-01

LiNi0.4Co0.2Mn0.4O2 material synthesized at different temperatures by using LiNO3-LiCl and LiNO3-KNO3 molten salt as a reaction medium. The phase purity of the samples obtained by powder X-ray diffraction measurement which suggests layered α-NaFeO2 type is obtained at 800-900 °C using LiNO3-LiCl flux and at 750-850 °C using LiNO3-KNO3 flux. The surface morphology change with flux media at different temperature are obtained by scanning electron microscopy analysis. The galvanostatic cycling results show that the high stable reversible discharge capacity of 155 (±3) mAh g-1 obtained for treated compound at 900 °C for 1 h (using LiNO3-LiCl) with coloumbic efficiency of 99%. The reversible discharge capacity of 140 and 130 (±3) mAh g-1 obtained for treated compound at 750 and 850 °C, respectively (using LiNO3-KNO3).

Novel band gap-tunable K-Na co-doped graphitic carbon nitride prepared by molten salt method

NASA Astrophysics Data System (ADS)

Zhao, Jiannan; Ma, Lin; Wang, Haoying; Zhao, Yanfeng; Zhang, Jian; Hu, Shaozheng

2015-03-01

Novel band gap-tunable K-Na co-doped graphitic carbon nitride was prepared by molten salt method using melamine, KCl, and NaCl as precursor. X-ray diffraction (XRD), N2 adsorption, Scanning electron microscope (SEM), UV-vis spectroscopy, Photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared catalysts. The CB and VB potentials of graphitic carbon nitride could be tuned from -1.09 and +1.55 eV to -0.29 and +2.25 eV by controlling the weight ratio of eutectic salts to melamine. Besides, ions doping inhibited the crystal growth of graphitic carbon nitride, enhanced the surface area, and increased the separation rate of photogenerated electrons and holes. The visible-light-driven Rhodamine B (RhB) photodegradation and mineralization performances were significantly improved after K-Na co-doping.

Density functional theory study of oxygen migration in molten carbonate

NASA Astrophysics Data System (ADS)

Lei, Xueling; Haines, Kahla; Huang, Kevin; Qin, Changyong

2016-02-01

The process of oxygen migration in alkali molten carbonate salts has been examined using density functional theory method. All geometries were optimized at the B3LYP/6-31G(d) level, while single point energy corrections were performed using MP4 and CCSD(T). At TS, a O-O-O linkage is formed and O-O bond forming and breaking is concerted. A cooperative ;cogwheel; mechanism as described in the equation of CO42- + CO32- →CO32- ⋯O ⋯CO32- →CO32- + CO42- is involved. The energy barrier is calculated to be 103.0, 136.3 and 127.9 kJ/mol through an intra-carbonate pathway in lithium, sodium and potassium carbonate, respectively. The reliability and accuracy of B3LYP/6-31G(d) were confirmed by CCSD(T). The calculated low values of activation energy indicate that the oxygen transfer in molten carbonate salts is fairly easy. In addition, it is found that lithium carbonate is not only a favorable molten carbonate salt for better cathode kinetics, but also it is widely used for reducing the melting point of Li/Na and Li/K eutectic MC mixtures. The current results imply that the process of oxygen reduction in MC modified cathodes is facilitated by the presence of MC, resulting in an enhancement of cell performance at low operating temperatures.

Control of molten salt corrosion of fusion structural materials by metallic beryllium

NASA Astrophysics Data System (ADS)

Calderoni, P.; Sharpe, P.; Nishimura, H.; Terai, T.

2009-04-01

A series of tests have been performed between 2001 and 2006 at the Safety and Tritium Applied Research facility of the Idaho National Laboratory to demonstrate chemical compatibility between the molten salt flibe (2LiF + BeF 2 in moles) and fusion structural materials once suitable fluoride potential control methods are established. The tests adopted metallic beryllium contact as main fluoride potential control, and the results have been published in recent years. A further step was to expose two specimens of low activation ferritic/martensitic steel 9Cr-2W to static corrosion tests that include an active corrosion agent (hydrofluoric gas) in controlled conditions at 530 °C, and the results of the tests are presented in this paper. The results confirmed the expected correlation of the HF recovery with the concentration of metallic impurities dissolved in the salt because of specimen corrosion. The metals concentration dropped to levels close to the detectable limit when the beryllium rod was inserted and increased once the content of excess beryllium in the system had been consumed by HF reduction and specimen corrosion progressed. Metallographic analysis of the samples after 500 h exposure in reactive conditions showed evidence of the formation of unstable chromium oxide layers on the specimen's surface.

Control of molten salt corrosion of fusion structural materials by metallic beryllium

DOE Office of Scientific and Technical Information (OSTI.GOV)

P. Calderoni; P. Sharpe; H. Nishimura

2009-04-01

A series of tests have been performed between 2001 and 2006 at the Safety and Tritium Applied Research facility of the Idaho National Laboratory to demonstrate chemical compatibility between the molten salt flibe (2LiF+BeF2 in moles) and fusion structural materials once suitable fluoride potential control methods are established. The tests adopted metallic beryllium contact as main fluoride potential control, and the results have been published in recent years. A further step was to expose two specimens of low activation ferritic/martensitic steel 9Cr-2W to static corrosion tests that include an active corrosion agent (hydrofluoric gas) in controlled conditions at 530 C,more » and the results of the tests are presented in this paper. The results confirmed the expected correlation of the HF recovery with the concentration of metallic impurities dissolved in the salt because of specimen corrosion. The metals concentration dropped to level close to the detectable limit when the beryllium rod was inserted and increased once the content of excess beryllium in the system had been consumed by HF reduction and specimens corrosion progressed. Metallographic analysis of the samples after 500 hours exposure in reactive conditions showed evidence of the formation of unstable chromium oxide layers on the specimens surface.« less

Interplay between structure and transport properties of molten salt mixtures of ZnCl2-NaCl-KCl: A molecular dynamics study.

PubMed

Manga, Venkateswara Rao; Swinteck, Nichlas; Bringuier, Stefan; Lucas, Pierre; Deymier, Pierre; Muralidharan, Krishna

2016-03-07

Molten mixtures of network-forming covalently bonded ZnCl2 and network-modifying ionically bonded NaCl and KCl salts are investigated as high-temperature heat transfer fluids for concentrating solar power plants. Specifically, using molecular dynamics simulations, the interplay between the extent of the network structure, composition, and the transport properties (viscosity, thermal conductivity, and diffusion) of ZnCl2-NaCl-KCl molten salts is characterized. The Stokes-Einstein/Eyring relationship is found to break down in these network-forming liquids at high concentrations of ZnCl2 (>63 mol. %), while the Eyring relationship is seen with increasing KCl concentration. Further, the network modification due to the addition of K ions leads to formation of non-bridging terminal Cl ions, which in turn lead to a positive temperature dependence of thermal conductivity in these melts. This new understanding of transport in these ternary liquids enables the identification of appropriate concentrations of the network formers and network modifiers to design heat transfer fluids with desired transport properties for concentrating solar power plants.

Production of chlorine from chloride salts

DOEpatents

Rohrmann, Charles A.

1981-01-01

A process for converting chloride salts and sulfuric acid to sulfate salts and elemental chlorine is disclosed. A chloride salt and sulfuric acid are combined in a furnace where they react to produce a sulfate salt and hydrogen chloride. Hydrogen chloride from the furnace contacts a molten salt mixture containing an oxygen compound of vanadium, an alkali metal sulfate and an alkali metal pyrosulfate to recover elemental chlorine. In the absence of an oxygen-bearing gas during the contacting, the vanadium is reduced, but is regenerated to its active higher valence state by separately contacting the molten salt mixture with an oxygen-bearing gas.

The origin of the conductivity maximum in molten salts. II. SnCl{sub 2} and HgBr{sub 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aravindakshan, Nikhil P.; Kuntz, Colin M.; Gemmell, Kyle E.

2016-09-07

The phenomenon of electrical conductivity maxima of molten salts versus temperature during orthobaric (closed-vessel) conditions is further examined via ab initio simulations. Previously, in a study of molten BiCl{sub 3}, a new theory was offered in which the conductivity falloff at high temperatures is due not to traditional ion association, but to a rise in the activation energy for atomic ions hopping from counterion to counterion. Here this theory is further tested on two more inorganic melts which exhibit conductivity maxima: another high-conducting melt (SnCl{sub 2}, σ{sub max} = 2.81 Ω{sup −1} cm{sup −1}) and a low-conducting one (HgBr{sub 2},more » σ{sub max} = 4.06 × 10{sup −4} Ω{sup −1} cm{sup −1}). First, ab initio molecular dynamics simulations were performed and again appear successful in reproducing the maxima for both these liquids. Second, analysis of the simulated liquid structure (radial distributions, species concentrations) was performed. In the HgBr{sub 2} case, a very molecular liquid like water, a clear Grotthuss chain of bromide transfers was observed in simulation when seeding the system with a HgBr{sup +} cation and HgBr{sub 3}{sup −} anion. The first conclusion is that the hopping mechanism offered for molten BiCl{sub 3} is simply the Grotthuss mechanism for conduction, applicable not just to H{sup +} ions, but also to halide ions in post-transition-metal halide melts. Second, it is conjectured that the conductivity maximum is due to rising activation energy in network-covalent (halide-bridging) melts (BiCl{sub 3}, SnCl{sub 2}, PbCl{sub 2}), but possibly a falling Arrhenius prefactor (collision frequency) for molecular melts (HgBr{sub 2}).« less

Molten salt synthesis of La0.8Sr0.2MnO3 powders for SOFC cathode electrode

NASA Astrophysics Data System (ADS)

Gu, Sin-il; Shin, Hyo-soon; Hong, Youn-woo; Yeo, Dong-hun; Kim, Jong-hee; Nahm, Sahn; Yoon, Sang-ok

2012-08-01

For La0.8Sr0.2MnO3 (LSM) perovskite, used as the cathode material for solid oxide fuel cells (SOFC), it is known that the formation of a triple-phase-boundary is restrained due to the formation of a second phase at the YSZ/electrode interface at high temperature. To decrease the 2nd phase, lowering the sintering temperature has been used. LSM powder was synthesized by molten salt synthesis method to control its particle size, shape, and agglomeration. We have characterized the phase formation, particle size, shape, and sintering behavior of LSM in the synthesis using the variation of KCl, LiCl, KF and its mixed salts as raw materials. In the case of KCl and KCl-KF salts, the particle size and shape of the LSM was well controlled and synthesized. However, in the case of LiCl and KCl-LiCl salts, LiMnOx as 2nd phase and LSM were synthesized simultaneously. In the case of the mixed salt of KCl-KF, the growth mechanism of the LSM particle was changed from `diffusion-controlled' to `reaction-controlled' according to the amount of mixed salt. The sintering temperature can be decreased below 1000 °C by using the synthesized LSM powder.

Electrolytic synthesis of carbon nanotubes from carbon dioxide in molten salts and their characterization

NASA Astrophysics Data System (ADS)

Novoselova, I. A.; Oliinyk, N. F.; Volkov, S. V.; Konchits, A. A.; Yanchuk, I. B.; Yefanov, V. S.; Kolesnik, S. P.; Karpets, M. V.

2008-05-01

Carbon nanotubes (CNTs) were synthesized from CO 2 dissolved in molten salts using the novel electrolytic method developed by the authors. The electrolysis were carried out under current and potential controls. To establish the actual current and potential ranges, the electroreduction of carbon dioxide dissolved in the halide melts under an excess pressure up to 15 bar was studied by cyclic voltammetry on glassy-carbon (GC) electrode at a temperature of 550 °C. The electrochemical-chemical-electrochemical mechanism of CO 2 electroreduction was offered for explanation of the obtained results. The structure, morphology, and electronic properties of the CNTs obtained were studied using SEM, TEM, X-ray and electron diffraction analysis, Raman and ESR spectroscopy. It was found that the majority of the CNTs are multi-walled (MWCNTs), have curved form, and most often agglomerate into bundles. Almost all CNTs are filled partly with electrolyte salt. Except MWCNTs the cathode product contains carbon nanofibers, nanographite, and amorphous carbon. The dependences of CNT's yield, their diameter, and structure peculiarities against the electrolysis regimes were established.

Development of high temperature transport technology for LiCl-KCl eutectic salt in pyroprocessing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sung Ho; Lee, Hansoo; Kim, In Tae

The development of high-temperature transport technologies for molten salt is a prerequisite and a key issue in the industrialization of pyro-reprocessing for advanced fuel cycle scenarios. The solution of a molten salt centrifugal pump was discarded because of the high corrosion power of a high temperature molten salt, so the suction pump solution was selected. An apparatus for salt transport experiments by suction was designed and tested using LiC-KCl eutectic salt. The experimental results of lab-scale molten salt transport by suction showed a 99.5% transport rate (ratio of transported salt to total salt) under a vacuum range of 100 mtorrmore » - 10 torr at 500 Celsius degrees. The suction system has been integrated to the PRIDE (pyroprocessing integrated inactive demonstration) facility that is a demonstrator using non-irradiated materials (natural uranium and surrogate materials). The performance of the suction pump for the transport of molten salts has been confirmed.« less

Large-scale synthesis of monodisperse magnesium ferrite via an environmentally friendly molten salt route.

PubMed

Lou, Zhengsong; He, Minglong; Wang, Ruikun; Qin, Weiwei; Zhao, Dejian; Chen, Changle

2014-02-17

Sub-micrometer-sized magnesium ferrite spheres consisting of uniform small particles have been prepared using a facile, large-scale solid-state reaction employing a molten salt technique. Extensive structural characterization of the as-prepared samples has been performed using scanning electron microscope, transmission electron microscopy, high-resolution transmission electron microscopy, selected area electron diffraction, and X-ray diffraction. The yield of the magnesium ferrite sub-micrometer spheres is up to 90%, and these sub-micrometer spheres are made up of square and rectangular nanosheets. The magnetic properties of magnesium ferrite sub-micrometer spheres are investigated, and the magnetization saturation value is about 24.96 emu/g. Moreover, the possible growth mechanism is proposed based on the experimental results.

Molten salt corrosion of heat resisting alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong-Moreno, A.; Salgado, R.I.M.; Martinez, L.

1995-09-01

This paper is devoted to the study of the corrosion behavior of eight high chromium alloys exposed to three different oil ash deposits with V/(Na+S) atomic ratios 0.58, 2.05 and 13.43, respectively. The alloys were exposed to ash deposits at 750 and 900 C; in this temperature range some deposit constituents have reached their melting point developing a molten salt corrosion process. The group of alloys tested included four Fe-Cr-Ni steels UNS specifications S304000, S31000, N08810 and N08330; two Fe-Cr alloys, UNS S44600 and alloy MA 956; and two Ni-base alloys, UNS N06333 and UNS N06601. The deposits and themore » exposed surfaces were characterized by chemical analysis, XRD, DTA, SEM and x-ray microanalysis. The oil-ash corrosion resistance of alloys is discussed in terms of the characteristics of corrosion product scales, which are determined by interaction between the alloy and the corrosive environment. All the alloys containing nickel exhibited sulfidation when were exposed at 750 C, but at 900 C only those without aluminum presented sulfidation or sulfidation and oxidation, while the alloys containing aluminum only exhibited internal oxidation. In spite of good resistance to corrosion by oil-ash deposits, 446-type alloy might not be suitable for temperatures higher than 750 C because of embrittlement caused by excessive sigma-phase precipitation. Alloy MA956 showed highest corrosion resistance at 900 C to oil-ash deposits with high vanadium content.« less

Probes and monitors for the study of solidification of molten semiconductors

NASA Technical Reports Server (NTRS)

Sadoway, D. R.

1986-01-01

The purpose is to examine solidification in the LiCl-KCl system to determine if phenomena such as solute rejection can be obseved by laser schlieren imaging. Molten salts have attributes that make them attractive as physical models in solidification studies. With optical techniques of investigation such as schlieren imaging, it is possible to study fluid flow phenomena in molten salts and to watch the trajectory of the solid-liquid interface.

Al/Pb lightweight grids prepared by molten salt electroless plating for application in lead-acid batteries

NASA Astrophysics Data System (ADS)

Hong, Bo; Jiang, Liangxing; Hao, Ketao; Liu, Fangyang; Yu, Xiaoying; Xue, Haitao; Li, Jie; Liu, Yexiang

2014-06-01

In this paper, a lightweight Pb plated Al (Al/Pb) grid was prepared by molten salt electroless plating. The SEM and bonding strength test show that the lead coating is deposited with a smooth surface and firm combination. CV test shows that the electrochemical properties of Al/Pb electrodes are stable. 2.0 V single-cell flooded lead-acid batteries with Al/Pb grids as negative collectors are assembled and the performances including 20 h capacity, rate capacity, cycle life, internal resistance are investigated. The results show that the cycle life of Al/Pb-grid cells is about 475 cycles and can meet the requirement of lead-acid batteries. Al/Pb grids are conducive to the refinement of PbSO4 grain, and thereby reduce the internal resistance of battery and advance the utilization of active mass. Moreover, weight of Al/Pb grid is only 55.4% of the conventional-grid. In this way, mass specific capacity of Al/Pb-grid negatives is 17.8% higher and the utilization of active mass is 6.5% higher than conventional-grid negatives.

Effects of molten-salt/ionic-liquid mixture on extraction of docosahexaenoic acid (DHA)-rich lipids from Aurantiochytrium sp. KRS101.

PubMed

Choi, Sun-A; Jung, Joo-Young; Kim, Kyochan; Kwon, Jong-Hee; Lee, Jin-Suk; Kim, Seung Wook; Park, Ji-Yeon; Yang, Ji-Won

2014-11-01

In this study, lipid extraction from Aurantiochytrium sp. was performed using a molten-salt/ionic-liquid mixture. The total fatty acid content of Aurantiochytrium sp. was 478.8 mg/g cell, from which 145 mg/g cell (30.3% of total fatty acids) of docosahexaenoic acid (DHA) was obtained. FeCl3·6H2O showed a high lipid extraction yield (207.9 mg/g cell), when compared with that of [Emim]OAc, which was only 118.1 mg/g cell; notably however, when FeCl3·6H2O was mixed with [Emim]OAc (5:1, w/w), the yield was increased to 478.6 mg/g cell. When lipid was extracted by the FeCl3·6H2O/[Emim]OAc mixture at a 5:1 (w/w) blending ratio under 90 °C, 30 min reaction conditions, the fatty acid content of the extracted lipid was a high purity 997.7 mg/g lipid, with most of the DHA having been extracted (30.2% of total fatty acids). Overall, lipid extraction from Aurantiochytrium sp. was enhanced by the synergistic effects of the molten-salt/ionic-liquid mixture with different ions.

The procedure and results of calculations of the equilibrium isotopic composition of a demonstration subcritical molten salt reactor

NASA Astrophysics Data System (ADS)

Nevinitsa, V. A.; Dudnikov, A. A.; Blandinskiy, V. Yu.; Balanin, A. L.; Alekseev, P. N.; Titarenko, Yu. E.; Batyaev, V. F.; Pavlov, K. V.; Titarenko, A. Yu.

2015-12-01

A subcritical molten salt reactor with an external neutron source is studied computationally as a facility for incineration and transmutation of minor actinides from spent nuclear fuel of reactors of VVER-1000 type and for producing 233U from 232Th. The reactor configuration is chosen, the requirements to be imposed on the external neutron source are formulated, and the equilibrium isotopic composition of heavy nuclides and the key parameters of the fuel cycle are calculated.

The procedure and results of calculations of the equilibrium isotopic composition of a demonstration subcritical molten salt reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nevinitsa, V. A., E-mail: Neviniza-VA@nrcki.ru; Dudnikov, A. A.; Blandinskiy, V. Yu.

2015-12-15

A subcritical molten salt reactor with an external neutron source is studied computationally as a facility for incineration and transmutation of minor actinides from spent nuclear fuel of reactors of VVER-1000 type and for producing {sup 233}U from {sup 232}Th. The reactor configuration is chosen, the requirements to be imposed on the external neutron source are formulated, and the equilibrium isotopic composition of heavy nuclides and the key parameters of the fuel cycle are calculated.

Electrochemical concentration measurements for multianalyte mixtures in simulated electrorefiner salt

NASA Astrophysics Data System (ADS)

Rappleye, Devin Spencer

The development of electroanalytical techniques in multianalyte molten salt mixtures, such as those found in used nuclear fuel electrorefiners, would enable in situ, real-time concentration measurements. Such measurements are beneficial for process monitoring, optimization and control, as well as for international safeguards and nuclear material accountancy. Electroanalytical work in molten salts has been limited to single-analyte mixtures with a few exceptions. This work builds upon the knowledge of molten salt electrochemistry by performing electrochemical measurements on molten eutectic LiCl-KCl salt mixture containing two analytes, developing techniques for quantitatively analyzing the measured signals even with an additional signal from another analyte, correlating signals to concentration and identifying improvements in experimental and analytical methodologies. (Abstract shortened by ProQuest.).

Temperature dependence of laser-induced fluorescence of Tb3+Tb3+ in molten LiCl-KCl eutectic

NASA Astrophysics Data System (ADS)

C., E.; -E., Jung | S.; | W., Bae; Cha | I., A.; Bae | Y., J.; | K., Park; Song

2011-01-01

Fluorescence spectra and lifetimes originated from both 5D3 →7FJ and 5D4 →7FJ transitions of Tb3+ were measured using time-resolved laser fluorescence spectroscopy in order to investigate the excited state relaxation in a molten salt medium. A cross-relaxation energy transfer of 5D3 →5D4 resulted in rise and decay behaviors in fluorescence signal waveforms of 5D4 →7FJ transitions. The fluorescence intensity ratios of 5D4 →7F5 to 5D3 →7F4 decreased drastically when the temperature of molten salt increased. This result suggests that the cross-relaxation effect becomes weakened with increasing temperature. In addition, a strong increase of the 5D4 emission over the 5D3 emission was observed at high Tb3+ concentration.

Molten Salt Assisted Self-Assembly: Synthesis of Mesoporous LiCoO2 and LiMn2 O4 Thin Films and Investigation of Electrocatalytic Water Oxidation Performance of Lithium Cobaltate.

PubMed

Saat, Gülbahar; Balci, Fadime Mert; Alsaç, Elif Pınar; Karadas, Ferdi; Dag, Ömer

2018-01-01

Mesoporous thin films of transition metal lithiates (TML) belong to an important group of materials for the advancement of electrochemical systems. This study demonstrates a simple one pot method to synthesize the first examples of mesoporous LiCoO 2 and LiMn 2 O 4 thin films. Molten salt assisted self-assembly can be used to establish an easy route to produce mesoporous TML thin films. The salts (LiNO 3 and [Co(H 2 O) 6 ](NO 3 ) 2 or [Mn(H 2 O) 4 ](NO 3 ) 2 ) and two surfactants (10-lauryl ether and cethyltrimethylammonium bromide (CTAB) or cethyltrimethylammonium nitrate (CTAN)) form stable liquid crystalline mesophases. The charged surfactant is needed for the assembly of the necessary amount of salt in the hydrophilic domains of the mesophase, which produces stable metal lithiate pore-walls upon calcination. The films have a large pore size with a high surface area that can be increased up to 82 m 2 g -1 . The method described can be adopted to synthesize other metal oxides and metal lithiates. The mesoporous thin films of LiCoO 2 show promising performance as water oxidation catalysts under pH 7 and 14 conditions. The electrodes, prepared using CTAN as the cosurfactant, display the lowest overpotentials in the literature among other LiCoO 2 systems, as low as 376 mV at 10 mA cm -2 and 282 mV at 1 mA cm -2 . © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A new thermal conductivity probe for high temperature tests for the characterization of molten salts.

PubMed

Bovesecchi, G; Coppa, P; Pistacchio, S

2018-05-01

A new thermal conductivity probe for high temperature (HT-TCP) has been built and tested. Its design and construction procedure are adapted from the ambient temperature thermal conductivity probe (AT-TCP) due to good performance of the latter device. The construction procedure and the preliminary tests are accurately described. The probe contains a Pt wire as a heater and a type K thermocouple (TC) as a temperature sensor, and its size is so small (0.6 mm in diameter and 60 mm in length) as to guarantee a length to diameter ratio of about 100. Calibration tests with glycerol for temperatures between 0 °C and 60 °C have shown good agreement with literature data, within 3%. Preliminary tests were also carried on a ternary molten salt for Concentrated Solar Power (CSP) (18% in mass of NaNO 3 , 52% KNO 3 , and 30% LiNO 3 ) at 120 °C and 150 °C. Obtained results are within λ range of the Hitec ® salt (53% KNO 3 , 7% NaNO 3 , 40% NaNO 2 ). Unfortunately, at the higher temperature tested (200 °C), the viscosity of the salt highly decreases, and free convection starts, making the measurements unreliable.

A new thermal conductivity probe for high temperature tests for the characterization of molten salts

NASA Astrophysics Data System (ADS)

Bovesecchi, G.; Coppa, P.; Pistacchio, S.

2018-05-01

A new thermal conductivity probe for high temperature (HT-TCP) has been built and tested. Its design and construction procedure are adapted from the ambient temperature thermal conductivity probe (AT-TCP) due to good performance of the latter device. The construction procedure and the preliminary tests are accurately described. The probe contains a Pt wire as a heater and a type K thermocouple (TC) as a temperature sensor, and its size is so small (0.6 mm in diameter and 60 mm in length) as to guarantee a length to diameter ratio of about 100. Calibration tests with glycerol for temperatures between 0 °C and 60 °C have shown good agreement with literature data, within 3%. Preliminary tests were also carried on a ternary molten salt for Concentrated Solar Power (CSP) (18% in mass of NaNO3, 52% KNO3, and 30% LiNO3) at 120 °C and 150 °C. Obtained results are within λ range of the Hitec® salt (53% KNO3, 7% NaNO3, 40% NaNO2). Unfortunately, at the higher temperature tested (200 °C), the viscosity of the salt highly decreases, and free convection starts, making the measurements unreliable.

MOLTEN FLUORIDE NUCLEAR REACTOR FUEL

DOEpatents

Barton, C.J.; Grimes, W.R.

1960-01-01

Molten-salt reactor fuel compositions consisting of mixtures of fluoride salts are reported. In its broadest form, the composition contains an alkali fluoride such as sodium fluoride, zirconium tetrafluoride, and a uranium fluoride, the latter being the tetrafluoride or trifluoride or a mixture of the two. An outstanding property of these fuel compositions is a high coeffieient of thermal expansion which provides a negative temperature coefficient of reactivity in reactors in which they are used.

Spinel lithium manganese oxide nanoparticles: unique molten salt synthesis strategy and excellent electrochemical performances.

PubMed

Wang, Xiong; Zhu, Juanjuan; Liu, Yingjie

2009-11-01

As a promising candidate cathode material, spinel lithium manganese oxide nanoparticles were successfully synthesized through a novel molten salt synthesis route at relatively low temperature, using manganese dioxide nanowires as precursor. A variety of techniques were applied to characterize the spinel nanomaterial, including X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The average particle size of the resulting spinel nanoparticles was about 80 nm with narrow distribution. As cathode material for rechargeable lithium ion battery, the electrochemical properties were investigated. All the results show that the electrochemical performances of the homogeneous spinel nanoparticles were improved, which might be ascribed to large specific surface area, fairly narrow size distribution, and the unique synthesis strategy.

A novel molten-salt electrochemical cell for investigating the reduction of uranium dioxide to uranium metal by lithium using in situ synchrotron radiation

PubMed Central

Brown, Leon D.; Abdulaziz, Rema; Jervis, Rhodri; Bharath, Vidal; Mason, Thomas J.; Reinhard, Christina; Connor, Leigh D.; Inman, Douglas; Brett, Daniel J. L.; Shearing, Paul R.

2017-01-01

A novel electrochemical cell has been designed and built to allow for in situ energy-dispersive X-ray diffraction measurements to be made during reduction of UO2 to U metal in LiCl–KCl at 500°C. The electrochemical cell contains a recessed well at the bottom of the cell into which the working electrode sits, reducing the beam path for the X-rays through the molten-salt and maximizing the signal-to-noise ratio from the sample. Lithium metal was electrodeposited onto the UO2 working electrode by exposing the working electrode to more negative potentials than the Li deposition potential of the LiCl–KCl eutectic electrolyte. The Li metal acts as a reducing agent for the chemical reduction of UO2 to U, which appears to proceed to completion. All phases were fitted using Le Bail refinement. The cell is expected to be widely applicable to many studies involving molten-salt systems. PMID:28244437

A novel molten-salt electrochemical cell for investigating the reduction of uranium dioxide to uranium metal by lithium using in situ synchrotron radiation.

PubMed

Brown, Leon D; Abdulaziz, Rema; Jervis, Rhodri; Bharath, Vidal; Mason, Thomas J; Atwood, Robert C; Reinhard, Christina; Connor, Leigh D; Inman, Douglas; Brett, Daniel J L; Shearing, Paul R

2017-03-01

A novel electrochemical cell has been designed and built to allow for in situ energy-dispersive X-ray diffraction measurements to be made during reduction of UO 2 to U metal in LiCl-KCl at 500°C. The electrochemical cell contains a recessed well at the bottom of the cell into which the working electrode sits, reducing the beam path for the X-rays through the molten-salt and maximizing the signal-to-noise ratio from the sample. Lithium metal was electrodeposited onto the UO 2 working electrode by exposing the working electrode to more negative potentials than the Li deposition potential of the LiCl-KCl eutectic electrolyte. The Li metal acts as a reducing agent for the chemical reduction of UO 2 to U, which appears to proceed to completion. All phases were fitted using Le Bail refinement. The cell is expected to be widely applicable to many studies involving molten-salt systems.

SEPARATION OF METAL SALTS BY ADSORPTION

DOEpatents

Gruen, D.M.

1959-01-20

It has been found that certain metal salts, particularly the halides of iron, cobalt, nickel, and the actinide metals, arc readily absorbed on aluminum oxide, while certain other salts, particularly rare earth metal halides, are not so absorbed. Use is made of this discovery to separate uranium from the rare earths. The metal salts are first dissolved in a molten mixture of alkali metal nitrates, e.g., the eutectic mixture of lithium nitrate and potassium nitrate, and then the molten salt solution is contacted with alumina, either by slurrying or by passing the salt solution through an absorption tower. The process is particularly valuable for the separation of actinides from lanthanum-group rare earths.

Electrolysis of a molten semiconductor

PubMed Central

Yin, Huayi; Chung, Brice; Sadoway, Donald R.

2016-01-01

Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb2S3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across the cell. As opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO2, CO and SO2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides. PMID:27553525

Electrolysis of a molten semiconductor

DOE PAGES

Yin, Huayi; Chung, Brice; Sadoway, Donald R.

2016-08-24

Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb 2S 3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across themore » cell. In conclusion, as opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO 2, CO and SO 2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides.« less

Electrolysis of a molten semiconductor.

PubMed

Yin, Huayi; Chung, Brice; Sadoway, Donald R

2016-08-24

Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb2S3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across the cell. As opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO2, CO and SO2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides.

Electrolysis of a molten semiconductor

NASA Astrophysics Data System (ADS)

Yin, Huayi; Chung, Brice; Sadoway, Donald R.

2016-08-01

Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb2S3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across the cell. As opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO2, CO and SO2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides.

Effect of cathode material on the electrorefining of U in LiCl-KCl molten salts

NASA Astrophysics Data System (ADS)

Lee, Chang Hwa; Kim, Tack-Jin; Park, Sungbin; Lee, Sung-Jai; Paek, Seung-Woo; Ahn, Do-Hee; Cho, Sung-Ki

2017-05-01

The influence of cathode materials on the U electrorefining process is examined using electrochemical measurements and SEM-EDX observations. Stainless steel (STS), Mo, and W electrodes exhibit similar U reduction/oxidation behavior in 500 °C LiCl-KCl-UCl3 molten salts, as revealed by the cyclic voltammograms. However, slight shifts are observed in the cathodic and anodic peak potentials at the STS electrode, which are related to the fast reduction/oxidation kinetics associated with this electrode. The U deposits on the Mo and W electrodes consist of uniform dendritic chains of U in rhomboidal-shaped crystals, whereas several U dendrites protruding from the surface are observed for the STS electrode. EDX mapping of the electrode surfaces reveals that simple scraping of the U dendrites from W electrodes pretreated in dilute HCl solutions to dissolve the residual salt, results in clear removal of the U deposits, whereas a thick U deposit layer strongly adheres to the STS electrode surface even after treatment. This result is expected to contribute to the development of an effective and continuous U recovery process using electrorefining.

Rapid mass production of two-dimensional metal oxides and hydroxides via the molten salts method

PubMed Central

Hu, Zhimi; Xiao, Xu; Jin, Huanyu; Li, Tianqi; Chen, Ming; Liang, Zhun; Guo, Zhengfeng; Li, Jia; Wan, Jun; Huang, Liang; Zhang, Yanrong; Feng, Guang; Zhou, Jun

2017-01-01

Because of their exotic electronic properties and abundant active sites, two-dimensional (2D) materials have potential in various fields. Pursuing a general synthesis methodology of 2D materials and advancing it from the laboratory to industry is of great importance. This type of method should be low cost, rapid and highly efficient. Here, we report the high-yield synthesis of 2D metal oxides and hydroxides via a molten salts method. We obtained a high-yield of 2D ion-intercalated metal oxides and hydroxides, such as cation-intercalated manganese oxides (Na0.55Mn2O4·1.5H2O and K0.27MnO2·0.54H2O), cation-intercalated tungsten oxides (Li2WO4 and Na2W4O13), and anion-intercalated metal hydroxides (Zn5(OH)8(NO3)2·2H2O and Cu2(OH)3NO3), with a large lateral size and nanometre thickness in a short time. Using 2D Na2W4O13 as an electrode, a high performance electrochemical supercapacitor is achieved. We anticipate that our method will enable new path to the high-yield synthesis of 2D materials for applications in energy-related fields and beyond. PMID:28555669

Molten salt oxidation: a versatile and promising technology for the destruction of organic-containing wastes.

PubMed

Yao, Zhitong; Li, Jinhui; Zhao, Xiangyang

2011-08-01

Molten salt oxidation (MSO), a robust thermal but non-flame process, has the inherent capability of destroying organic constituents in wastes, while retaining inorganic and radioactive materials in situ. It has been considered as an alternative to incineration and may be a solution to many waste disposal problems. The present review first describes the history and development of MSO, as well as design and engineering details, and then focuses on reaction mechanisms and its potential applications in various wastes, including hazardous wastes, medical wastes, mixed wastes, and energetic materials. Finally, the current status of and prospects for the MSO process and directions for future research are considered. Copyright © 2011 Elsevier Ltd. All rights reserved.

Treatment of electrochemical cell components with lithium tetrachloroaluminate (LiAlCl.sub.4) to promote electrolyte wetting

DOEpatents

Eberhart, James G.; Battles, James E.

1980-01-01

Electrochemical cell components such as interelectrode separators, retaining screens and current collectors are contacted with lithium tetrachloroaluminate prior to contact with molten electrolytic salt to improve electrolyte wetting. The LiAlCl.sub.4 can be applied in powdered, molten or solution form but, since this material has a lower melting point than the electrolytic salt used in high-temperature cells, the powdered LiAlCl.sub.4 forms a molten flux prior to contact by the molten electrolyte when both materials are initially provided in solid form. Components of materials such as boron nitride and other materials which are difficult to wet with molten salts are advantageously treated by this process.

Corrosion of alloys in a chloride molten salt (NaCl-LiCl) for solar thermal technologies

DOE PAGES

Gomez-Vidal, Judith C.; Tirawat, Robert

2016-06-01

Next-generation solar power conversion systems in concentrating solar power (CSP) applications require high-temperature advanced fluids in the range of 600–800 °C. Current commercial CSP plants use molten nitrate salt mixtures as the heat transfer fluid and the thermal energy storage (TES) media while operating with multiple hours of energy capacity and at temperatures lower than 565 °C. At higher temperatures, the nitrates cannot be used because they decompose. Molten chloride salts are candidates for CSP applications because of their high decomposition temperatures and good thermal properties; but they can be corrosive to common alloys used in vessels, heat exchangers, andmore » piping at these elevated temperatures. In this article, we present the results of the corrosion evaluations of several alloys in eutectic 34.42 wt% NaCl – 65.58 wt% LiCl at 650–700 °C in nitrogen atmosphere. Electrochemical evaluations were performed using open-circuit potential followed by a potentiodynamic polarization sweep. Corrosion rates were determined using Tafel slopes and Faraday's law. A temperature increase of as little as 50 °C more than doubled the corrosion rate of AISI stainless steel 310 and Incoloy 800H compared to the initial 650 °C test. These alloys exhibited localized corrosion. Inconel 625 was the most corrosion-resistant alloy with a corrosion rate of 2.80±0.38 mm/year. For TES applications, corrosion rates with magnitudes of a few millimeters per year are not acceptable because of economic considerations. Additionally, localized corrosion (intergranular or pitting) can be catastrophic. Furthermore, corrosion-mitigation approaches are required for advanced CSP plants to be commercially viable.« less

Corrosion of alloys in a chloride molten salt (NaCl-LiCl) for solar thermal technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gomez-Vidal, Judith C.; Tirawat, Robert

Next-generation solar power conversion systems in concentrating solar power (CSP) applications require high-temperature advanced fluids in the range of 600–800 °C. Current commercial CSP plants use molten nitrate salt mixtures as the heat transfer fluid and the thermal energy storage (TES) media while operating with multiple hours of energy capacity and at temperatures lower than 565 °C. At higher temperatures, the nitrates cannot be used because they decompose. Molten chloride salts are candidates for CSP applications because of their high decomposition temperatures and good thermal properties; but they can be corrosive to common alloys used in vessels, heat exchangers, andmore » piping at these elevated temperatures. In this article, we present the results of the corrosion evaluations of several alloys in eutectic 34.42 wt% NaCl – 65.58 wt% LiCl at 650–700 °C in nitrogen atmosphere. Electrochemical evaluations were performed using open-circuit potential followed by a potentiodynamic polarization sweep. Corrosion rates were determined using Tafel slopes and Faraday's law. A temperature increase of as little as 50 °C more than doubled the corrosion rate of AISI stainless steel 310 and Incoloy 800H compared to the initial 650 °C test. These alloys exhibited localized corrosion. Inconel 625 was the most corrosion-resistant alloy with a corrosion rate of 2.80±0.38 mm/year. For TES applications, corrosion rates with magnitudes of a few millimeters per year are not acceptable because of economic considerations. Additionally, localized corrosion (intergranular or pitting) can be catastrophic. Furthermore, corrosion-mitigation approaches are required for advanced CSP plants to be commercially viable.« less

Destabilization of yttria-stabilized zirconia induced by molten sodium vanadate-sodium sulfate melts

NASA Technical Reports Server (NTRS)

Nagelberg, A. S.; Hamilton, J. C.

1985-01-01

The extent of surface destabilization of ZrO2 - 8 wt percent Y2O3 ceramic disks was determined after exposure to molten salt mixtures of sodium sulfate containing up to 15 mole percent sodium metavanadate (NaVO3) at 1173 K. The ceramic surface was observed to transform from the cubic/tetragonal to monoclinic phase, concurrent with chemical changes in the molten salt layer in contact with the ceramic. Significant attack rates were observed in both pure sulfate and metavanadate sulfate melts. The rate of attack was found to be quite sensitive to the mole fraction of vanadate in the molten salt solution and the partial pressure of sulfur trioxide in equilibrium with the salt melt. The observed parabolic rate of attack is interpreted to be caused by a reaction controlled by diffusion in the salt that penetrates into the porous layer formed by the destabilization. The parabolic rate constant in mixed sodium metavanadate - sodium sulfate melts was found to be proportional to the SO3 partial pressure and the square of the metavanadate concentration. In-situ Raman spectroscopic measurements allowed simultaneous observations of the ceramic phases and salt chemistry during the attack process.

Molten salt synthesis and characterization of Li4Ti5-xMnxO12 (x = 0.0, 0.05 and 0.1) as anodes for Li-ion batteries

NASA Astrophysics Data System (ADS)

Nithya, V. D.; Kalai Selvan, R.; Vediappan, Kumaran; Sharmila, S.; Lee, Chang Woo

2012-11-01

Sub-micrometer sized Li4Ti5-xMnxO12 (x = 0.0, 0.05 and 0.1) particles were synthesized by a single step molten salt method using LiCl-KCl as a flux. The synthesized material was structurally characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectra. The XRD analysis revealed the particles to be highly crystalline and have a face-centered cubic spinel structure. The presence of possible functional group was confirmed through FTIR analysis. The FE-SEM images showed the particles to be polyhedral in shape with uniform size distribution. It was also revealed that there was a particle size reduction with the effect of Mn4+ dopant ions. The electrochemical studies performed using cyclic voltammogram (CV), charge-discharge, and electrochemical impedance analysis (EIS) indicate that Li4Ti4.9Mn0.1O4 possesses a better discharge capacity (305 mAh/g), cycling stability, and charge carrier conductivity than both Li4Ti4.95Mn0.05O12 (265 mAh/g) and Li4Ti5O12 (240 mAh/g). The cycling stability reveals that the acceptable capacity fading was observed even after 20th cycle. The results of electrochemical studies infer that Li4Ti4.9Mn0.1O4 could be utilized as a suitable anode material for Li-ion batteries.

Synthesis of functional carbon nanospheres by a composite-molten-salt method and amperometric sensing of hydrogen peroxide.

PubMed

Wang, Xue; Hu, Chenguo; Xiong, Yufeng; Zhang, Cuiling

2013-02-01

Functional carbon nanospheres have been synthesized from analytically pure glucose by a composite-molten-salt (CMS) method. Field emission scanning electron microscopy, transmission electron microscopy, Raman and Fourier transformation infra-red spectroscopy indicate the carbon nanospheres are solid, bond hybridisation (sp2/sp3) and with many functional groups on their surfaces. Amperometric sensor based on the synthesized carbon nanospheres have been fabricated without pretreatment or modification. The detection of hydrogen peroxide exhibits high sensitivity and good selectivity. The electrochemical measurement of these nanospheres demonstrates much superior performance to those of the carbon nanospheres synthesized by hydrothermal method.

Aerosol-assisted molten salt synthesis of NaInS(2) nanoplates for use as a new photoanode material.

PubMed

Mann, Amanda K P; Wicker, Susanne; Skrabalak, Sara E

2012-12-04

NaInS(2) , a H(2) -evolving photocatalyst, is synthesized as single-crystalline hexagonal plates by coupling a molten salt synthesis with ultrasonic spray pyrolysis (USP) for the first time. USP NaInS(2) films are used as a new photoanode material and have an initial photocurrent of ≈37 μA/cm(2) upon illumination and activities 25 times greater than films made from a standard non-aerosol NaInS(2) sample. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molten Salt Thermal Energy Storage Systems

NASA Technical Reports Server (NTRS)

Maru, H. C.; Dullea, J. F.; Kardas, A.; Paul, L.; Marianowski, L. G.; Ong, E.; Sampath, V.; Huang, V. M.; Wolak, J. C.

1978-01-01

The feasibility of storing thermal energy at temperatures of 450 C to 535 C in the form of latent heat of fusion was examined for over 30 inorganic salts and salt mixtures. Alkali carbonate mixtures were chosen as phase-change storage materials in this temperature range because of their relatively high storage capacity and thermal conductivity, moderate cost, low volumetric expansion upon melting, low corrosivity, and good chemical stability. Means of improving heat conduction through the solid salt were explored.

Synthesis of LaMnO3 in molten chlorides: effect of preparation conditions.

PubMed

Vradman, Leonid; Zana, Jonatan; Kirschner, Alon; Herskowitz, Moti

2013-07-14

LaMnO3 perovskite was successfully synthesized in molten chlorides. In order to explore the effect of the molten salt type, NaCl-KCl and LiCl-KCl eutectic mixtures were employed as a liquid medium for the perovskite formation process. The synthesis included heating the La-nitrate, Mn-nitrate and chlorides mixture to above the melting point of the corresponding chlorides. This procedure yielded a LaMnO3 phase integrated in the fused chloride matrix. Washing with water removed the salts completely, yielding pure LaMnO3 perovskite crystals. The synthesis without molten salt at 800 °C yielded several by-products in addition to the LaMnO3 phase, while with LiCl-KCl the pure perovskite phase was obtained at temperatures as low as 600 °C. Variation of temperature in the range 600-800 °C for LiCl-KCl and 700-800 °C for NaCl-KCl had no significant effect either on the morphology or on the particle size of the product. On the other hand, the effect of the molten salt type on the morphology and size of perovskite particles was remarkable. The synthesis in NaCl-KCl resulted in sub-micron LaMnO3 particles with shapes that range from truncated hexahedrons to spheres, while in LiCl-KCl mostly cubic particles of up to 2-microns were obtained. The effect of the molten salt type on LaMnO3 perovskite formation is explained based on the nucleation and crystal growth model and difference in the melting point of eutectic mixtures.

Interaction between Oxygen and Molten Carbonate: A DFT Study

DTIC Science & Technology

2011-11-01

ion (O2-) are considered. The combination of oxygen with single carbonate ( CO3 2-) forms molecular complexes, CO5 2- and CO4 2-, respectively... CO3 2- is 105.3 kJ/mol. Structures of (K2CO3)4, ( Li2CO3)4 and (LiKCO3)4 were also studied as simplest cluster models for molten carbonates with...approximately 650 °C, these salts melt and become conductive to carbonate ions ( CO3 2-). These three complexes were chosen as a treatment to enhance

Method for making a uranium chloride salt product

DOEpatents

Miller, William E [Naperville, IL; Tomczuk, Zygmunt [Lockport, IL

2004-10-05

The subject apparatus provides a means to produce UCl.sub.3 in large quantities without incurring corrosion of the containment vessel or associated apparatus. Gaseous Cl is injected into a lower layer of Cd where CdCl.sub.2 is formed. Due to is lower density, the CdCl.sub.2 rises through the Cd layer into a layer of molten LiCl--KCL salt where a rotatable basket containing uranium ingots is suspended. The CdCl.sub.2 reacts with the uranium to form UCl.sub.3 and Cd. Due to density differences, the Cd sinks down to the liquid Cd layer and is reused. The UCl.sub.3 combines with the molten salt. During production the temperature is maintained at about 600.degree. C. while after the uranium has been depleted the salt temperature is lowered, the molten salt is pressure siphoned from the vessel, and the salt product LiCl--KCl-30 mol % UCl.sub.3 is solidified.

Mechanical and tribological behaviour of molten salt processed self-lubricated aluminium composite under different treatments

NASA Astrophysics Data System (ADS)

Kannan, C.; Ramanujam, R.

2018-05-01

The aim of this research work is to evaluate the mechanical and tribological behaviour of Al 7075 based self-lubricated hybrid nanocomposite under different treated conditions viz. as-cast, T6 and deep cryo treated. In order to overcome the drawbacks associated with conventional stir casting, a combinational approach that consists of molten salt processing, ultrasonic assistance and optimized mechanical stirring is adopted in this study to fabricate the nanocomposite. The mechanical characterisation tests carried out on this nanocomposite reveals an improvement of about 39% in hardness and 22% in ultimate tensile strength possible under T6 condition. Under specific conditions, the wear rate can be reduced to the extent of about 63% through the usage of self-lubricated hybrid nanocomposite under T6 condition.

Molten-salt synthesis and composition-dependent luminescent properties of barium tungsto-molybdate-based solid solution phosphors

NASA Astrophysics Data System (ADS)

Xiang-Hong, He; Zhao-Lian, Ye; Ming-Yun, Guan; Ning, Lian; Jian-Hua, Sun

2016-02-01

Pr3+-activated barium tungsto-molybdate solid solution phosphor Ba(Mo1-zWz)O4:Pr3+ is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated octahedron and exhibits deep-red-emitting upon blue light excitation. Powder x-ray diffraction and Raman spectroscopy techniques are utilized to investigate the formation of solid solution phosphor. The luminescence behaviors depend on the resulting composition of the microcrystals with fixed Pr3+-doping concentration, while the host lattices remain in a scheelite structure. The forming solid solution via the substitution of [WO4] for [MoO4] can significantly enhance its luminescence, which may be due to the fact that Ba(Mo1-zWz)O4:Pr3+ owns well-defined facets and uniform morphologies. Owing to its properties of high phase purity, well-defined facets, highly uniform morphologies, exceptional chemical and thermal stabilities, and stronger emission intensity, the resulting solid solution phosphor is expected to find potential applications in phosphor-converted white light-emitting diodes (LEDs). Project supported by the Construction Fund for Science and Technology Innovation Group from Jiangsu University of Technology, China, the Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, China (Grant No. KHK1409), the Priority Academic Program Development of Jiangsu Higher Education Institutions, China, and the National Natural Science Foundation of China (Grant No. 21373103).