Mercury Flow Research Articles

Isotope Effect of Mercury Diffusion in Air

Identifying and reducing impacts from mercury sources in the environment remains a considerable challenge and requires process based models to quantify mercury stocks and flows. The stable isotope composition of mercury in environmental samples can help address this challenge by serving as a tracer of specific sources and processes. Mercury isotope variations are small and result only from isotope fractionation during transport, equilibrium, and transformation processes. Because these processes occur in both industrial and environmental settings, knowledge of their associated isotope effects is required to interpret mercury isotope data. To improve the mechanistic modeling of mercury isotope effects during gas phase diffusion, an experimental program tested the applicability of kinetic gas theory. Gas-phase elemental mercury diffusion through small bore needles from finite sources demonstrated mass dependent diffusivities leading to isotope fractionation described by a Rayleigh distillation model. The measured relative atomic diffusivities among mercury isotopes in air are large and in agreement with kinetic gas theory. Mercury diffusion in air offers a reasonable explanation of recent field results reported in the literature.

Transport of stabilized engineered silver (Ag) nanoparticles through porous sandstones

Engineered nanoparticles are increasingly applied in consumer products and concerns are rising regarding their risk as potential contaminants or carriers for colloid-facilitated contaminant transport. Engineered silver nanoparticles (AgNP) are among the most widely used nanomaterials in consumer products. However, their mobility in groundwater has been scarcely investigated. In this study, transport of stabilized AgNP through porous sandstones with variations in mineralogy, pore size distribution and permeability is investigated in laboratory experiments with well-defined boundary conditions. The AgNP samples were mainly characterized by asymmetric flow field-flow fractionation coupled to a multi-angle static laser light detector and ultraviolet-visible spectroscopy for determination of particle size and concentration. The rock samples are characterized by mercury porosimetry, flow experiments and solute tracer tests. Solute and AgNP breakthrough was quantified by applying numerical models considering one kinetic site model for particle transport. The transport of AgNP strongly depends on pore size distribution, mineralogy and the solution ionic strength. Blocking of attachment sites results in less reactive transport with increasing application of AgNP mass. AgNPs were retained due to physicochemical filtration and probably due to straining. The results demonstrate the restricted applicability of AgNP transport parameters determined from simplified experimental model systems to realistic environmental matrices.

Correlation between simulations and cavitation-induced erosion damage in Spallation Neutron Source target modules after operation

An explicit finite element (FE) technique developed for estimating dynamic strain in the Spallation Neutron Source (SNS) mercury target module vessel is now providing insight into cavitation-induced erosion patterns observed on interior surfaces of SNS targets during post-irradiation examination. The technique uses an empirically developed material model for the mercury that describes its volumetric stiffness combined with a tensile pressure cut-off limit to approximate the threshold and effect of cavitation. The longest period each point in the mercury is at the tensile cut-off threshold is denoted as “saturation time”. Patterns of saturation time can be obtained from the FE simulations and are being positively correlated with observed damage patterns as a qualitative measure of damage potential. Saturation time has been advocated by collaborators at the Japan Proton Accelerator Research Complex (J-PARC) as a factor in predicting bubble nuclei growth and collapse intensity. Larger ratios of maximum bubble-size-to-nucleus result in greater bubble collapse intensity; longer saturation times correlate to greater ratios. With the recent development of a user subroutine for the FE solver, saturation time is now provided over the entire mercury domain. Saturation time contour maps agree with patterns of damage seen on the SNS inner vessel beam window and elsewhere. The other simulation result which seems to correlate with observed damage patterns is the local mercury velocity. Related R&D has provided evidence that damage is mitigated by flow velocity. Surfaces which are near regions of low mercury velocity appear to be more vulnerable to damage than those where the mercury flow is strong and sustained. By combining the patterns of saturation time and velocity a viable explanation for observed damage patterns is presented.

Small gas bubble experiment for mitigation of cavitation damage and pressure waves in short-pulse mercury spallation targets

Populations of small helium gas bubbles were introduced into a flowing mercury experiment test loop to evaluate mitigation of beam-pulse induced cavitation damage and pressure waves. The test loop was developed and thoroughly tested at the Spallation Neutron Source (SNS) prior to irradiations at the Los Alamos Neutron Science Center–Weapons Neutron Research (LANSCE–WNR) facility. Twelve candidate bubblers were evaluated over a range of mercury flow and gas injection rates by use of a novel optical measurement technique that accurately assessed the generated small bubble size distributions. Final selection for irradiation testing included two variations of a swirl bubbler provided by Japan Proton Accelerator Research Complex (J-PARC) collaborators and one orifice bubbler developed at SNS. Bubble populations of interest consisted of sizes up to 150μm in radius with achieved gas volume fractions in the 10−5–10−4 range. The nominal WNR beam pulse used for the experiment created energy deposition in the mercury comparable to SNS pulses operating at 2.5MW. Nineteen test conditions were completed each with 100 pulses, including variations on mercury flow, gas injection and protons per pulse. The principal measure of cavitation damage mitigation was pitting damage assessment on test specimens that were manually replaced for each test condition. Damage assessment was done after radiation decay and decontamination by optical and laser profiling microscopy with damaged area fraction and maximum pit depth being the more valued results. Damage was reduced by flow alone; the best mitigation from bubble injection was to one-third that of stagnant mercury. Other data collected included surface motion tracking by three Laser Doppler Vibrometers (LDV), test loop wall dynamic strain, beam diagnostics for charge and beam profile assessment, embedded hydrophones and pressure sensors, and sound measurement by a suite of conventional and contact microphones.

Anthropogenic Mercury Flows in India and Impacts of Emission Controls

India is a major emitter of mercury, a pollutant of global importance. However, quantitative information on mercury flows in the country is lacking. Here, we quantify major transfer pathways for anthropogenic mercury, its emissions to the environment (air, water, soil), and storage in consumer products and anthropogenic sinks (e.g., landfills) in India in the period 2001-2020, and evaluate the potential influence of six pollution control measures. Total mercury emissions in India were approximately 415 tonnes in 2001, 310 tonnes in 2010, and are projected to rise to 540 tonnes in 2020. In 2010, 76% of these emissions went to the atmosphere. The most important emission sources to atmosphere are coal power plants and zinc production. Pesticides were the most important source for emissions to soil in 2005 and dental amalgam in later years. Mercury stocks in products rose from 700 tonnes in 2001 to 1125 tonnes in 2010, and in landfills and ash-made structures (e.g., embankments) from 920 tonnes in 2001 to 1450 tonnes in 2010. These stocks are expected to rise further and may be regarded as stored toxicity, which may become a concern in the future. Total mercury emissions can be reduced by about 50% by combining pollution control measures that target different mercury emission sources.

Experimental study on heat transfer and pressure drop in mercury flow system for spallation neutron source

In the design of MW-class spallation target system, using mercury to produce practical neutron applications, keeping the highest level of safety is vitally important. To establish the safety of spallation target system, it is essential to understand the thermal hydraulic properties of mercury. Through thermal hydraulic experiments using a mercury experimental loop, which flows at the rate of 1.2 m3/hr maximum, the following facts were experimentally confirmed. The wall friction factor was relatively larger than the Blasius correlation due to the effects of wall roughness. The heat transfer coefficients agreed well with the Subbotin correlation. Furthermore, for validation of the design analysis code, thermal hydraulic analyses were conducted by using the STAR-CD code under the same conditions as the experiments. Analytical results showed good agreement with the experimental results, using optimized turbulent Prandtl number and mesh size.

Patterned Turbulence in Liquid Metal Flow: Computational Reconstruction of the Hartmann Experiment

We present results of a numerical analysis of Hartmann's historical experiments on flows of mercury in pipes and ducts under the influence of magnetic fields. The computed critical parameters for the laminar-turbulent transition as well as the friction coefficients are in excellent agreement with Hartmann's data. The simulations provide a first detailed view of the flow structures that are experimentally inaccessible. Novel flow regimes with localized turbulent spots near the sidewalls parallel to the magnetic field and otherwise laminar flow are discovered. We finally suggest how these predictions can be tested in a transparent fluid using optical flow measurement.

Simulation of charged and excited particle transport in the low-current discharge in argon-mercury mixture

Simulation of the electron, ion and metastable excited atom transport in the argon-mercury mixture low-current discharge is fulfilled. Distributions of the particle densities along the discharge gap under different mixture temperatures are obtained and it is demonstrated that the principal mechanism of mercury ion generation is the Penning ionization of mercury atoms by argon metastables, which contribution grows sharply with the mixture temperature due to mercury density increase. Calculations show that the mercury and argon ion flow densities near the cathode are of the same order already under the relative mercury content of about 10−4 corresponding at the argon pressure 103 Pa to the mixture temperature 30 C. Therefore, at the room temperature the electrodes of mercury illuminating lamps at the stage of their ignition are sputtered predominantly by mercury ions.

The Validation of Methods to Calculate Gas-Oil Relative Permeability Using Capillary Pressure Data from South Pars Reservoir

Gas-oil relative permeability is the most important parameter in the simulation of fluid flow in the gas condensate reservoirs. Experimental measurements of relative permeability need core samples with regular shape, which is costly and time consuming. On the other hand, experimental data of relative permeability may also have significant error and uncertainty in many cases. One source of uncertainty is that the input to numerical simulator is uncertain and inaccurate; it may be reduced if the number of input parameters is decreased, especially if the parameters with the greatest uncertainty are avoided. It is possible to impose only capillary pressure data, because relative permeability can be predicted consistently using specific models. The present methods, which are based on capillary pressure, considered the porous media as a bundle of capillary tubes; they indeed are mercury flow paths that are filled during the mercury injection capillary pressure test at the certain value of capillary pressure. The authors applied the existing capillary models for relative permeability calculations to a gas condensate reservoir. The tested samples have a wide range of liquid permeability from less than 1 to 18 md. The results of this study show that the Purcell model has the best fit with experimental data for wetting phase (oil), and the differences between measured and model data were almost negligible. The predictions of nonwetting phase (gas) relative permeability were a good agreement with experimental data except for Purcell model. Results reveal that the relative permeability could be computed by using accurate capillary pressure data.

Simulation of flow and mercury transport in Upper East Fork Poplar Creek, Oak Ridge, Tennessee

AbstractAs a result of nuclear processing activities started back in the 1950s, the environment in the vicinity of the Y‐12 National Security Complex (Y‐12 NSC) in Oak Ridge, Tennessee, and surrounding watersheds has been contaminated by nearly 1,000 tons of elementary mercury. To comply with the state and federal surface water quality standards, a significant reduction in mercury concentration to parts‐per‐trillion levels has been proposed. In order to analyze the mercury cycle in the environment and provide forecasting capabilities for the flow and transport of mercury within the Upper East Fork Poplar Creek (UEFPC) watershed, an integrated surface and subsurface flow and transport model has been developed using the hydrodynamic and transport numerical package, MIKE, developed by the Danish Hydraulic Institute. The model has been constructed and calibrated using an extensive collection of historical records (i.e., hydrological data, and mercury concentration measurements in groundwater, soil, and sediment) obtained from the Oak Ridge Environmental Information System database. Daily fluctuations in stream flow, as a result of scattered rainfall, flooding, and flow augmentation, resuspend the contaminated streambed sediments and/or erode the polluted streambank soil and provide a secondary source of mercury to the creek. In order to investigate the significance of sediment‐mercury interactions on the fate and transport of mercury within the UEFPC study domain, simulations were performed for two different cases (i.e., with and without consideration of sediment‐mercury interactions). Computed total suspended solids and mercury concentrations at the integration point of the creek are compared with the corresponding historical records in both cases. As confirmed by the numerical simulations, a substantial portion of the mercury detected in the river is likely in the form of sediment particle–bound mercury (i.e., mercury particulates). © 2012 Wiley Periodicals, Inc.

Trophic relationships and mercury biomagnification in Brazilian tropical coastal food webs

The present study investigated trophic relationships and mercury flow through food webs of three tropical coastal ecosystems: Guanabara, Sepetiba and Ilha Grande bays. The investigation was carried out through carbon and nitrogen stable isotopes (δ13C, δ15N) and total mercury (THg) determination in muscle from 35 species, including crustacean, cephalopod, fish and dolphin species. Detritivorous species showed the lowest average δ15N values in all bays. These species were 13C enriched in Sepetiba and Ilha Grande bays, suggesting the presence of 13C enriched macroalgae in their diet. The highest mean δ15N values were found in fish and benthic invertebrate feeders, as well as in species presenting demerso-pelagic feeding habit. The carbon and nitrogen isotopic findings showed different trophic relationship in food webs from Sepetiba, Guanabara and Ilha Grande bays. Guanabara Bay showed to be depleted in δ15N compared to both Sepetiba and Ilha Grande bays. The latter finding suggests substantial contribution of atmospheric nitrogen fixation by cyanobacteria. A positive linear relationship was found between logTHg concentrations and δ15N values for Guanabara and Ilha Grande bays, but not for Sepetiba Bay. Our findings showed trophic magnification factors (TMF) above 1, demonstrating that THg is being biomagnified up the food chains in Rio de Janeiro bays.

Status of R&D on mitigating the effects of pressure waves for the Spallation Neutron Source mercury target

The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory has been conducting R&D on mitigating the effects of pressure waves in mercury spallation targets since 2001. More precisely, cavitation damage of the target vessel caused by the short beam pulse threatens to limit its lifetime more severely than radiation damage as well as limit its ultimate power capacity – and hence its neutron intensity performance. The R&D program has moved from verification of the beam-induced damage phenomena to study of material and surface treatments for damage resistance to the current emphasis on gas injection techniques for damage mitigation. Two techniques are being worked on: injection of small dispersed gas bubbles that mitigate the pressure waves volumetrically; and protective gas walls that isolate the vessel from the damaging effects of collapsing cavitation bubbles. The latter has demonstrated good damage mitigation during in-beam testing with limited pulses, and adequate gas wall coverage at the beam entrance window has been demonstrated with the SNS mercury target flow configuration using a full scale mercury test loop. A question on the required area coverage remains which depends on results from SNS target post irradiation examination. The small gas bubble technique has been less effective during past in-beam tests but those results were with un-optimized and un-verified bubble populations. Another round of in-beam tests with small gas bubbles is planned for 2011.The first SNS target was removed from service in mid 2009 and samples were cut from two locations at the target’s beam entrance window. Through-wall damage was observed at the innermost mercury vessel wall (not a containment wall). The damage pattern suggested correlation with the local mercury flow condition which is nearly stagnant at the peak damage location. Detailed post irradiation examination of the samples is under way that will assess the erosion and measure irradiation-induced changes in mechanical properties. Similar samples were cut from the second SNS target after it was removed from service in mid 2010. More extensive damage was observed on the target inner wall but damage to the containment wall was minimal.

수은에 대한 물질흐름분석 및 인체 위해성평가

Concerned about the harmful effects of mercury on human, the flows of mercury need to be analyzed to trace where it is used and decide how to manage it. In the study the substance flows of mercury are identified through the SFA (Substance Flow Analysis) and the effects of mercury on human are examined using HRA (Human Risk Assessment). The MFA study shows that the total consumption of mercury in 2009 is reduced by 42%, compared to 2000. It is used mainly in lighting appliances such as HID (High-Intensity Discharge) lamp, fluorescent lamp, and cold cathode fluorescent lamp. It is mainly input to construction and electronic & electricity industry and waste mercury is recovered from descarded lighting appliances. At present, however, the collected mercury from the discarded products is disposed because of technical and economical difficulties. In the past the domestic demand of mercury was much larger than now and thus, the environmental emission of mercury is mainly from the 'manufacturing' stage. On the other hand, at present proper management of waste mercury becomes critical, since recently the demand of mercury decreases significantly and at the same time the increased amounts of mercury containing products are discarded. The HRA is carried out to examine the probability and likely-hood of hazardous impact of mercury to human for each region. The disposal plant of mercury-containing products shows much higher potential risks on human than more populated place with high consumption of mercury-containing products. It is due to that the amounts of discarded products with contain mercury increase, while the amounts of new mercury-containing products decrease because of international regulations. Thus, the management of waste mercury is critical in order to reduce the risks of mercury to human. In addition, the amounts of mercury emission are analyzed for 16 cities/provinces in Korea using the factors which consider the characteristics of different mercury containing products. Human exposure assessment is performed. considering the amount of mercury exposed by air inhaled and water intake. The results of risk characterization show that the most harmful place for human risk is different from the place with the largest amount of mercury emission.

Consumer perspectives on household hazardous waste management in Japan

We give an overview of the management systems of household hazardous waste (HHW) in Japan and discuss the management systems and their risks. To get basic information, we conducted a survey of consumers to discover their behavior and awareness of HHW items throughout the entire life cycle, which is made up of the purchase, use, and disposal of a product. The results showed that many people hold end-of-life batteries, fluorescent lamps, empty spray cans, and others in their houses after use. Also, the results showed that a lot of such waste items were discarded in waste streams different from those stipulated by local governments. In particular, many people do not remove NiCd batteries inside products such as shavers or cordless phones before discarding. On the other hand, people’s knowledge of and concern regarding the risks, collection, and recycling of HHW were high. When information about the risks was specifically presented in the questionnaire, people tended to show a more positive intention to participate in a collection and recycling system compared to those who were not presented with such information. Our studies on NiCd batteries and fluorescent lamps showed that it is important to collect and recycle HHW to control the domestic and international flows of cadmium and mercury.

Design of Omni-Directional Tilt Sensor Based on Machine Vision

This paper presents a new Omni-Directional Tilt Sensor (ODTS), which consists of the LED light, transparent cone-shaped closed container, mercury, camera, embedded systems and so on. The volume of the mercury in the container is equal to half of the container’s. When the detected surface is horizontal, the shape of mercury in the image captured by the camera is a black disc since the mercury is lightproof. When the detected surface tilts, the mercury flows and the mercury surface always maintains horizontally due to the gravity force of the earth. At this time, some area of the transparent cone-shaped closed container is not shaded by mercury and the border of the mercury’s shape in the captured image is a half circle and a half ellipse. Thus there is a translucent crescent-shaped area in the image. With analyzing this area by the specific algorithm based on machine vision, the tilt angle and directional angle can be obtained. The experimental results show that the ODTS proposed has some advantages, such as simple maintenance, high precision, wide range, low cost, real-time, reliability and high visualization.

LIQUID METAL FLOW CONTROL BY DC ELECTROMAGNETIC PUMPS

The cooling system of high-density thermal power requires fluids of high thermal conductivity, such as liquid metals. Electromagnetic pumps can be used to liquid metal fluid flow control in cooling circuits. The operation of electromagnetic pumps used to flow control is based on Lorentz force. This force can be achieved by magnetic field and electric current interaction, controlled by external independent power supplies. This work presents the electromagnetic pump operational principles, the IEAv development scheme and the BEMC-1 simulation code. The theoretical results of BEMC-1simulation are compared to electromagnetic pump operation experimental data, validating the BEMC-1 code. This code is used to evaluate the DC electromagnetic pump performance applied to Mercury flow control and others liquid metal such as Sodium, Lead and Bismuth, used in nuclear fast reactors.

Distribution of Microbubble Sizes and Behavior of Large Bubbles in Mercury Flow in a Mockup Target Model of J-PARC

Click to increase image sizeClick to decrease image sizeKEYWORDS: mercury spallation targetmicrobubble injectionJ-PARCcavitation damagepressure wavebubble size distributionbeam windowmercury loop testTTF

Distribution of Microbubble Sizes and Behavior of Large Bubbles in Mercury Flow in a Mockup Target Model of J-PARC

KEYWORDS: mercury spallation targetmicrobubble injectionJ-PARCcavitation damagepressure wavebubble size distributionbeam windowmercury loop testTTF

Cavitation damage experiments for mercury spallation targets at the LANSCE – WNR in 2008

Proton beam experiments investigating cavitation damage in short pulse mercury spallation targets were performed at LANSCE – WNR in July of 2008. They included two main areas for investigation: damage dependence on mercury velocity using geometry more prototypic to the SNS target than previously employed and damage dependence on incident proton beam flux intensity. The flow dependence experiment employed six test targets with mercury velocity in the channel ranging from 0 to more than 4 m/s. Each was hit with 100 WNR beam pulses with peak proton flux equivalent to that of SNS operating at 2.7 MW. Damage dependence on incident proton beam flux intensity was also investigated with three intensity levels used on simple rectangular shaped targets without mercury flow. Intensity variation was imposed by focusing the beam differently while maintaining protons per pulse. This kept total energy deposited in each target constant. A fourth test target was hit with various beams: constant protons and varied spot size; constant spot size and varied protons. No damage will be assessed in this case. Instead, acoustic emissions associated with cavitation collapse were measured by laser Doppler vibrometer (LDV) from readings of exterior vessel motions as well as by mercury wetted acoustic transducers. This paper will provide a description of the experiment and present available results. Damage assessment will require several months before surface analysis can be completed and was not available in time for IWSMT-9.

Lead, Cadmium and Mercury Flow Analysis – Decision Support for Austrian Environmental Policy

This paper discusses the support for environmental policy decisions that can be provided by substance flow analysis (SFA). Flows and stocks of lead (Pb), cadmium (Cd) and mercury (Hg) are investigated through the Austrian economy and environment. Two advantages of SFA are emphasized: first, because SFA is based on the law of conservation of mass, input and output flows of processes have to be balanced. This balancing principle allows identifying data gaps and contradicting information supplied by different sources, and helps to calculate missing data. Second and most important for environmental policy making, SFA gives the whole picture and full transparency. It is instrumental in showing the combined effect of different environmental policy measures such as integrated product policy, consumer protection, emission control, and waste management on the economy of a country and its environment. SFA also helps to identify hot spots for which additional measures are required to reduce environmental pressure or to make use of secondary anthropogenic stocks. SFA results must be carefully interpreted in order to distinguish between beneficial and harmful flows and stocks, e. g. when materials are recycled that contain large amounts of hazardous heavy metals. For a comprehensive base to design future environmental policy, quantitative SFA needs to be amended by qualitative information, and by additional assessment tools.