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

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At least 1,099 records · Page 61
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Cerium dioxide (CeO2) nanoparticles decrease arsenite (As(III)) cytotoxicity to 16HBE14o- human bronchial epithelial cells

Highlights: • CeO{sub 2} NPs display a high adsorption capacity for As(III). • As(III) is highly toxic to lung 16HBE14o- cells (81% inhibition at 0.5 mg As/L). • As(III) adsorption onto CeO{sub 2} NPs decreased As(III) cytotoxicity on 16HBE14o- cells. • Cell uptake of As(III)-loaded CeO{sub 2} NPs did not lead to enhanced cytotoxicity. The production and application of engineered nanoparticles (NPs) are increasing in demand with the rapid development of nanotechnology. However, there are concerns that some of these novel materials could lead to emerging environmental and health problems. Some NPs are able to facilitate the transport of contaminants into cells/organisms via a “Trojan Horse” effect which enhances the toxicity of the adsorbed materials. In this work, we evaluated the toxicity of arsenite (As(III)) adsorbed onto cerium dioxide (CeO{sub 2}) NPs to human bronchial epithelial cells (16HBE14o-) using the xCELLigence real time cell analyzing system (RTCA). Application of 0.5 mg/L As(III) resulted in 81.3% reduction of cell index (CI, an RTCA measure of cell toxicity) over 48 h when compared to control cells exposed to medium lacking As(III). However, when the cells were exposed to 0.5 mg/L As(III) in the presence of CeO{sub 2} NPs (250 mg/L), the CI was only reduced by 12.9% compared to the control. The CeO{sub 2} NPs had a high capacity for As(III) adsorption (20.2 mg/g CeO{sub 2}) in the bioassay medium, effectively reducing dissolved As(III) in the aqueous solution and resulting in reduced toxicity. Transmission electron microscopy was used to study the transport of CeO{sub 2} NPs into 16HBE14o- cells. NP uptake via engulfment was observed and the internalized NPs accumulated in vesicles. The results demonstrate that dissolved As(III) in the aqueous solution was the decisive factor controlling As(III) toxicity of 16HBE14o- cells, and that CeO{sub 2} NPs effectively reduced available As(III) through adsorption. These data emphasize the evaluation of mixtures when assaying toxicity.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Final Report – Cooperative Research and Development Agreement between National Energy Technology Laboratory and Applied Spectra, Inc.

Groundwater resources can be contaminated by a variety of surface and subsurface sources. For instance, metals can be leached from surface dumps (e.g. landfills, etc.) and reach groundwater supplies by percolation though the soil. Additionally, subsurface activities such as geologic carbon storage (GCS) could result in contamination. In the event of CO2 leakage, freshwater above the injection site can potentially be contaminated with metals either originating from the formation fluids or leached from formation rocks by CO2 acidification. Detection of these contaminating metals is critical for maintaining water safety and providing an early warning of a containment breach. Therefore, a compact, subsurface capable laser induced breakdown spectroscopy (LIBS) based sensor has been developed for groundwater quality monitoring applications. LIBS sensor technology has been advanced from benchtop feasibility studies to a custom fabricated, watertight prototype. The all optical sensor head is built using a low cost passively Q-switched (PQSW) laser, which is fiber coupled to a control unit containing the pump laser and a gated spectrometer. Separating the LIBS excitation laser from the pump and spectrometer allows the expensive and fragile components to remain in a safe, central location while only the sensor head needs to enter the subsurface. Testing of the prototype sensors show Limits of Detection (LODs) comparable to benchtop, actively Q-switched systems and has verified that the fiber coupling and triggering schemes perform as desired.

McIntyre, Dustin↗
DOE OSTI2017

Salmonella Inactivation During Extrusion of an Oat Flour Model Food

Abstract Little research exists on Salmonella inactivation during extrusion processing, yet many outbreaks associated with low water activity foods since 2006 were linked to extruded foods. The aim of this research was to study Salmonella inactivation during extrusion of a model cereal product. Oat flour was inoculated with Salmonella enterica serovar Agona, an outbreak strain isolated from puffed cereals, and processed using a single‐screw extruder at a feed rate of 75 kg/h and a screw speed of 500 rpm. Extrudate samples were collected from the barrel outlet in sterile bags and immediately cooled in an ice–water bath. Populations were determined using standard plate count methods or a modified most probable number when populations were low. Reductions in population were determined and analyzed using a general linear model. The regression model obtained for the response surface tested was Log ( N R / N O ) = 20.50 + 0.82 T − 141.16a w – 0.0039 T 2 + 87.91 a w 2 ( R 2 = 0.69). The model showed significant ( p < 0.05) linear and quadratic effects of a w and temperature and enabled an assessment of critical control parameters. Reductions of 0.67 ± 0.14 to 7.34 ± 0.02 log CFU/g were observed over ranges of a w (0.72 to 0.96) and temperature (65 to 100 °C) tested. Processing conditions above 82 °C and 0.89 a w achieved on average greater than a 5‐log reduction of Salmonella . Results indicate that extrusion is an effective means for reducing Salmonella as most processes commonly employed to produce cereals and other low water activity foods exceed these parameters. Thus, contamination of an extruded food product would most likely occur postprocessing as a result of environmental contamination or through the addition of coatings and flavorings.

Anderson, Nathan M.↗
DOE OSTI2025

Geographic, sectoral, and constituent characteristics of US off‐site manufacturing wastewater disposal

This study employs recent US Environmental Protection Agency off-site manufacturing wastewater disposal data and a socioenvironmental assessment tool for the United States to understand the characteristics of such disposal in terms of geography, major contributing sectors and pollutants, and environmental impacts. Environmental impact analyses of manufacturing are insufficient without encompassing the extended physical boundary of waste management. Our analysis reveals that off-site manufacturing wastewater disposal occurs disproportionately in populations residing in census tracts already negatively impacted by environmental hazards (impacted populations, or IPs) with 44% of transfers and 55% of Risk Screening Environmental Indicators (RSEI) Hazard going to these areas, compared to their national share of 37%. Disposal hazard is concentrated in a small number of populations, with a Gini coefficient of 0.99 for RSEI Hazard. Four manufacturing sub-sectors are significant generators: Chemicals, Fabricated Metals, Primary Metals, and Transportation Equipment, with Chemicals off-site wastewater disposal largely occurring in IPs. For individual contaminants, chromium compounds and chromium represent more than 85% of the hazard but less than 10% of transfers. We explore transfer distances and waste generation and disposal hotspots, finding that the Midwest hosts a disproportionate share of off-site wastewater disposal. Further, RSEI Hazard steeply rises at shorter distances and plateaus over distances >500 miles, revealing opportunities to reduce hazard by reducing 20–500-mile transfers. Our findings strongly support targeted mitigation strategies like process substitutions, control technologies, on-site recycling and treatment, and minimizing transfer distances. This article met the requirements for a gold-gold JIE data openness badge described at http://jie.click/badges.

Fuchs, Heidi [Lawrence Berkeley National Laborator↗
DOE OSTI2012

SILICA GEL BEHAVIOR UNDER DIFFERENT EGS CHEMICAL AND THERMAL CONDITIONS: AN EXPERIMENTAL STUDY

Fractures and fracture networks are the principal pathways for migration of water and contaminants in groundwater systems, fluids in enhanced geothermal systems (EGS), oil and gas in petroleum reservoirs, carbon dioxide leakage from geological carbon sequestration, and radioactive and toxic industrial wastes from underground storage repositories. When dealing with EGS fracture networks, there are several major issues to consider, e.g., the minimization of hydraulic short circuits and losses of injected geothermal fluid to the surrounding formation, which in turn maximize heat extraction and economic production. Gel deployments to direct and control fluid flow have been extensively and successfully used in the oil industry for enhanced oil recovery. However, to the best of our knowledge, gels have not been applied to EGS to enhance heat extraction. In-situ gelling systems can either be organic or inorganic. Organic polymer gels are generally not thermostable to the typical temperatures of EGS systems. Inorganic gels, such as colloidal silica gels, however, may be ideal blocking agents for EGS systems if suitable gelation times can be achieved. In the current study, we explore colloidal silica gelation times and rheology as a function of SiO{sub 2} concentration, pH, salt concentration, and temperature, with preliminary results in the two-phase field above 100 C. Results at 25 C show that it may be possible to choose formulations that will gel in a reasonable and predictable amount of time at the temperatures of EGS systems.

02 PETROLEUM↗
DOE OSTI2025

Dark Energy Survey Year 6 Results: improved mitigation of spatially varying observational systematics with masking

As photometric surveys reach unprecedented statistical precision, systematic uncertainties increasingly dominate large-scale structure probes relying on galaxy number density. Defining the final survey footprint is critical, as it excludes regions affected by artefacts or suboptimal observing conditions. For galaxy clustering, spatially varying observational systematics, such as seeing, are a leading source of bias. Template maps of contaminants are used to derive spatially dependent corrections, but extreme values may fall outside the applicability range of mitigation methods, compromising correction reliability. The complexity and accuracy of systematics modelling depend on footprint conservativeness, with aggressive masking enabling simpler, robust mitigation. We present a unified approach to define the DES Year 6 joint footprint, integrating observational systematics templates and artefact indicators that degrade mitigation performance. This removes extreme values from an initial seed footprint, leading to the final joint footprint. By evaluating the DES Year 6 lens sample MagLim++ plus plus on this footprint, we enhance the Iterative Systematics Decontamination (ISD) method, detecting non-linear systematic contamination and improving correction accuracy. While the mask's impact on clustering is less significant than systematics decontamination, it remains non-negligible, comparable to statistical uncertainties in certain w(theta) scales and redshift bins. Supporting coherent analyses of galaxy clustering and cosmic shear, the final footprint spans 4031.04 deg2, setting the basis for DES Year 6 1x2pt, 2x2pt, and 3x2pt analyses. This work highlights how targeted masking strategies optimise the balance between statistical power and systematic control in Stage-III and -IV surveys.

Rodríguez-Monroy, M. [Madrid, IFT; IJCLab, Orsay]↗
DOE OSTI2012

Vertical Extraction Process Implemented at the 118-K-1 Burial Ground for Removal of Irradiated Reactor Debris from Silo Structures - 12431

The primary objective of a remediation project is the safe extraction and disposition of diverse waste forms and materials. Remediation of a solid waste burial ground containing reactor hardware and irradiated debris involves handling waste with the potential to expose workers to significantly elevated dose rates. Therefore, a major challenge confronted by any remediation project is developing work processes that facilitate compliant waste management practices while at the same time implementing controls to protect personnel. Traditional burial ground remediation is accomplished using standard excavators to remove materials from trenches and other excavation configurations often times with minimal knowledge of waste that will be encountered at a specific location. In the case of the 118-K-1 burial ground the isotopic activity postulated in historic documents to be contained in vertical cylindrical silos was sufficient to create the potential for a significant radiation hazard to project personnel. Additionally, certain reported waste forms posed an unacceptably high potential to contaminate the surrounding environment and/or workers. Based on process knowledge, waste management requirements, historic document review, and a lack of characterization data it was determined that traditional excavation techniques applied to remediation of vertical silos would expose workers to unacceptable risk. The challenging task for the 118-K-1 burial ground remediation project team then became defining an acceptable replacement technology or modification of an existing technology to complete the silo remediation. Early characterization data provided a good tool for evaluating the location of potential high exposure rate items in the silos. Quantitative characterization was a different case and proved difficult because of the large diameter of the silos and the potential for variable density of attenuating soils and waste forms in the silo. Consequently, the most relevant information supporting job planning and understanding of the conditions was the data obtained from the gross gamma meter that was inserted into each casing to provide a rough estimate of dose rates in the tubes. No added value was realized in attempting to quantify the source term and/or associate the isotopic activity with a particular actual waste form (e.g., sludge). Implementing the WRM system allowed monitoring of worker and boundary exposure rates from a distance, maintaining compliance with ALARA principles. This system also provided the project team early knowledge of items being removed that had high exposure rates associated with them, thus creating an efficient method of acknowledging an issue and arriving at a solution prior to having an upset condition. An electronic dosimeter with telemetry capability replaced the excavator mounted AMP-100 system approximately half way through remediation of the silos. Much higher connectivity efficiency was derived from this configuration. Increasing the data feed efficiency additionally led to less interruption of the remediation effort. Early in system testing process a process handicap on the excavator operator was acknowledged. A loss of depth perception resulted when maneuvering the excavator and bucket using the camera feed to an in-cab monitor. Considerable practice and mock-up testing allowed this handicap to be overcome. The most significant equipment failures involved the cable connection to the camera mounted between the clamshell bucket jaws and the video splitter in the excavator cab. Rotation of the clamshell bucket was identified as the cause of cable connection failures because of the cyclic twisting motion and continuous mechanical jarring of the connection. In-cab vibration was identified as the culprit in causing connection failures of the video splitter. While these failures were repaired, substantial production time was lost. Ultimately, the decision was made to purchase a second cable and higher quality video splitter eliminate the down time. An engineering improvement for future operations would be inserting cable pig tails at more stressed cable connection points to facilitate rapid change out of the cable should that be required. Overall, the system performed better than expected in a safe and efficient manner. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Subsurface Conditions Controlling Uranium Incorporation in Iron Oxides: A Redox Stable Sink

Toxic metals and radionuclides throughout the U.S. Department of Energy Complex pose a serious threat to ecosystems and to human health. Of particular concern is the redox-sensitive radionuclide uranium, which is classified as a priority pollutant in soils and groundwaters at most DOE sites owing to its large inventory, its health risks, and its mobility with respect to primary waste sources. The goal of this research was to contribute to the long-term mission of the Subsurface Biogeochemistry Program by determining reactions of uranium with iron (hydr)oxides that lead to long-term stabilization of this pervasive contaminant. The research objectives of this project were thus to (1) identify the (bio)geochemical conditions, including those of the solid-phase, promoting uranium incorporation in Fe (hydr)oxides, (2) determine the magnitude of uranium incorporation under a variety of relevant subsurface conditions in order to quantify the importance of this pathway when in competition with reduction or adsorption; (3) identify the mechanism(s) of U(VI/V) incorporation in Fe (hydr)oxides; and (4) determine the stability of these phases under different biogeochemical (inclusive of redox) conditions. Our research demonstrates that redox transformations are capable of achieving U incorporation into goethite at ambient temperatures, and that this transformation occurs within days at U and Fe(II) concentrations that are common in subsurface geochemical environments with natural ferrihydrites—inclusive of those with natural impurities. Increasing Fe(II) or U concentration, or initial pH, made U(VI) reduction to U(IV) a more competitive sequestration pathway in this system, presumably by increasing the relative rate of U reduction. Uranium concentrations commonly found in contaminated subsurface environments are often on the order of 1-10 μM, and groundwater Fe(II) concentrations can reach exceed 1 mM in reduced zones of the subsurface. The redox-driven U(V) incorporation mechanism may help to explain U retention in some geologic materials, improving our understanding of U-based geochronology and the redox status of ancient geochemical environments. Additionally, U(VI) may be incorporated within silicate minerals though encapsulation of U-bearing iron oxides, leading to a redox stable solid. Our research detailing previously unrecognized mechanism of U incorporation within sediment minerals may even lead to new approaches for in situ contamination remediation techniques, and will help refine models of U fate and transport in reduced subsurface zones.

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

Final Demolition and Disposition of 209-E Critical Mass Laboratory - 12267

The 209-E Critical Mass Laboratory was constructed in 1960 to provide a heavy shielded reactor room where quantities of plutonium or uranium in solution could be brought to near-critical configurations under carefully controlled and monitored conditions. In the late 1980's, the responsible contractor, Pacific Northwest National Laboratory (PNNL), was directed by the Department of Energy (DOE) to prepare the facility for unoccupied status. The facility was demolished under a Removal Action Work Plan pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). The funding for this project was provided by the American Recovery and Reinvestment Act (ARRA). The primary rooms of concern with regards to contamination in 209-E facility, which is over 9,000 square feet, are the criticality assembly room (CAR), the mix room, and the change room. The CAR contained two reactor hoods (HO-140 and HO-170), which each had a high efficiency particulate air (HEPA) filter system. The CAR contained 13 tanks ranging from 38 L (10 gal) to 401 L (106 gal). Tanks TK-109 and TK-110 are below grade, and were removed as part of this demolition and disposition remedy. Nonradiological and radiological hazardous substances were removed, decontaminated, or fixed in place, prior to demolition. Except for the removal of below grade tanks TK-109 and TK-110, the facility was demolished to slab-on-grade. PNNL performed stabilization and deactivation activities that included removal of bulk fissile material and chemicals, flushing tanks, stabilizing contamination within gloveboxes and hoods, and packaging and removing waste. The removal of the contaminated plutonium equipment and materials from the 209E facility presented a number of challenges similar in nature to those associated with the inventory reduction and cleanup activities at the Plutonium Finishing Plant. Although there were no bulk fissile materials or chemicals within the facility, there were residual radiological materials (isotopes of plutonium and americium) in the tanks and hoods. The complexity of the remedy was present because of the various configurations of the tanks and hoods, combined with the residual contaminants. Because of the weight and dimensional configuration, size reduction of the slab tanks, as well as removal and disposal of the different material used for moderation and absorption, were two examples of challenges that were resolved to complete the remedy. One of the key methods developed and implemented at the facility was the design and construction of a shroud to allow the cutting of the Pu contaminated tanks. The shroud design, development and implementation at the 209E Project was an example of enhanced work planning and task hazards analysis with worker involvement. This paper will present the lessons learned from the 209E facility inventory reduction activities including the shroud and other methodologies used. The initial Lessons Learned discussion for this project was scheduled for late January 2012. This facility is the first open-air demolition of a highly contaminated plutonium-contaminated facility accomplished by CH2M Hill under the Plateau Remediation Contract. The demolition was completed without spread of contamination to the workers and the surrounding area. As with any project of this complexity, there are significant accomplishments, as well as experience that can be applied to future demolition of plutonium-contaminated facilities on the Hanford Site. These experiences will be documented at a later date. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Methods and apparatus for use with extreme ultraviolet light having contamination protection

An apparatus for use with extreme ultraviolet (EUV) light comprising A) a duct having a first end opening, a second end opening and an intermediate opening intermediate the first end opening the second end opening, B) an optical component disposed to receive EUV light from the second end opening or to send light through the second end opening, and C) a source of low pressure gas at a first pressure to flow through the duct, the gas having a high transmission of EUV light, fluidly coupled to the intermediate opening. In addition to or rather than gas flow the apparatus may have A) a low pressure gas with a heat control unit thermally coupled to at least one of the duct and the optical component and/or B) a voltage device to generate voltage between a first portion and a second portion of the duet with a grounded insulative portion therebetween.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Urinary strontium and the risk of breast cancer: A case-control study in Guangzhou, China

Strontium has been widely used in industries like electronic and pharmacy. It has a carcinogenic potential, however, and no study has been conducted to evaluate its effects on cancer risk. The aim of this study was to explore the possible association between strontium and breast cancer risk in a case-control study including 240 incident invasive breast cancer patients and 246 age-matched controls. We measured the urinary concentrations of strontium by inductively coupled plasma mass spectrometry, and conducted face-to-face interviews to obtain information on potential breast cancer risk factors. Multivariable analysis was used to estimate the association. Creatinine-adjusted levels [median (25th, 75th) {mu}g/g] of strontium were 155.59 (99.05, 230.70) in the breast cancer patients and 119.62 (81.97, 163.76) in the controls. Women in the highest tertile of strontium showed 124% increased risk of breast cancer, when compared with those in the lowest tertile after adjustment for the potential risk factors [OR (95% CI): 2.24 (1.42-3.81)]. This association was particularly strong for HER2 positive breast cancer [OR (95% CI): 10.92 (3.53-33.77)], and only occurred among premenopausal women. These results suggest a potential role of strontium in the development of breast cancer and urge further studies on the environmental contamination and the physiological and pathological mechanisms of strontium.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Technetium Complexation with Multidentate Carboxylate-Containing Ligands: Trends in Redox and Solubility Phenomena

The chemistry of technetium (t 1/2 ( 99 Tc) = 2.11 × 10 5 years) is of particular importance in the context of nuclear waste disposal and historic contaminated sites. Polycarboxylate ligands may be present in some sites and are potentially capable of strong complexing interactions, thus increasing the solubility and mobility of 99 Tc under environmentally relevant conditions. This work aimed to determine the impact of five organic complexing ligands [L = oxalate, phthalate, citrate, nitrilotriacetate (NTA), and ethylenediaminetetraacetate (EDTA)] under anoxic, alkaline conditions (pH ≈ 9–13) on the solubility of technetium. X-ray absorption spectroscopy confirmed that TcO 2 (am,hyd) remained the solubility-controlling solid phase in undersaturation solubility experiments. Ligands with maximum coordination numbers (CN) ≥ 3 (EDTA, NTA, and citrate) exhibited an increase in solubility from pH 9 to 11, while ligands with CN ≤ 2 (oxalate and phthalate) at all investigated pH and CN ≥ 3 at pH ≈ 13 were outcompeted by hydrolysis reactions. Though most available thermodynamic values were determined under acidic conditions, these models satisfactorily explained high-pH undersaturation solubility of technetium for citrate and NTA, whereas experimental data for Tc(IV)–EDTA were highly overestimated. Finally, this work illustrates the predominance of hydrolysis under hyperalkaline conditions and provides experimental support for existing thermodynamic models of Tc–L except Tc–EDTA, which requires further research regarding aqueous speciation and solubility.

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

HE Production Update at JLab - Introducing an Enhanced Nitrogen Purge for Clean String Assembly

A major limitation to cryomodule performance is field emission caused by particulates within the superconducting cavities. To reduce contamination of the inner surfaces during assembly in a cleanroom, the whole string can be connected to a purge system, which maintains a constant overpressure of dry, clean nitrogen gas. Following successes of similar systems at XFEL and Fermilab, Jefferson Lab followed this example for the production of LCLS-II HE cryomodules. Implementing this system required new procedures, infrastructure, and hardware, as well as significant testing of the system before production began. This paper will summarize the implemented controls and procedures, including lessons learned from Fermilab, as well as the results of mock-up tests. Based on the latter, the system was used to assemble the first article string in April 2022, and was also used during a rework required due to issues with cold FPC ceramics two months later. The benefits of using a purge system with regards to procedure, time savings, and added flexibility for potential rework have already proven to provide a significant improvement for the production of LCLS-II-HE cryomodules at Jefferson Lab.

Owen, P. D.↗
DOE OSTI2024

Quantifying microbial roles in environmental iron oxidation via an integrated kinetics, `omics and metabolic modeling study (Final Report)

Iron oxyhydroxides are extremely reactive components of environmental systems, and therefore exert a strong influence on biogeochemical cycles. These oxyhydroxides strongly adsorb many biologically-relevant elements, including organic carbon and phosphate, as well as a wide range of metals including uranium and actinide species. Thus, the formation mechanism of iron oxyhydroxides are key to understanding both nutrient and contaminant cycling. Microorganisms can catalyze iron oxidation and promote the formation of Fe biominerals and thus are increasingly recognized as important players in biogeochemical cycling. However, it is completely unknown how much of environmental iron oxidation is biologically mediated versus abiotic, and various challenges in studying microbial iron oxidation have hindered accurate incorporation into hydrobiogeochemical models. The overarching goal of our work was to quantify and constrain microbial iron oxidation rates and use ‘omics to gain insight into the controls on this process, while developing tools to enable integration of biotic iron oxidation into hydrobiogeochemical models. Our work focused on the Savannah River Site (SRS) in South Carolina, where extensive microbial iron oxidation has been observed. At Tims Branch, part of the Argonne National Laboratory Wetland Hydrobiogeochemistry Science Focus Area (Argonne SFA), where groundwater discharges into a stream, iron-oxidizing microbial mats form and appear to be a major sink of uranium. In the wetlands that surround Tims Branch, there are wide swaths of iron microbial mats and flocs (mobilized mat). We measured biotic and abiotic iron oxidation rates using mats and water sampled from these sites and found that iron oxidation is primarily carried out by chemolithotrophic microorganisms. The resulting rate constants can be incorporated into models. These mats were characterized by metagenomics and metatranscriptomics, which showed that aerobic chemolithotrophs were the dominant iron-oxidizing bacteria (FeOB), and these included Gallionellaceae and Leptothrix, and possibly Rhodoferax, which is known as an Fe-reducer but may also oxidize Fe(II). This demonstrated that diverse FeOB can coexist and suggests that there are a range of niches and therefore drivers of chemolithotrophic iron oxidation. Analysis of reconstructed genomes strongly suggests that a major factor in diversity is carbon source, as genomes contained varied pathways for autotrophy and heterotrophy. We performed an in-depth analysis of Leptothrix ochracea genomes, since this sheath-former is one of the primary mat builders, yet its physiology remained unresolved. A combination of genomics, transcriptomics, and metabolic modeling suggest that L. ochracea grows mixotrophically using a combination of Fe(II) and organics for energy and both inorganic and organic carbon to create biomass. This contrasts with the largely autotrophic Gallionellaceae (Gallionella, Sideroxydans, and Ferriphaselus) also present in the mats and flocs. Remarkably, multiple FeOB, both Leptothrix and Gallionellaceae, showed activity in response to Fe(II) in live mat incubations. We tracked the gene expression of individual MAGs to Fe(II) and found that various autotrophic and heterotrophic FeOB responded to Fe(II), increasing expression of both carbon fixation and organic utilization genes. The results of the integrated field, kinetics, and omics studies give detailed insight into 1) the taxa that oxidize Fe, and 2) how they connect Fe, C, and N cycles. Towards the goal of connecting omics data to hydrobiogeochemical models, we worked with the KBase team to create a template metabolic model for chemolithotrophic iron oxidation. We initially modeled the well-characterized isolate Gallionellaceae Sideroxydans lithotrophicus, and also applied the model to the mixotroph L. ochracea. In all, we have characterized diverse FeOB in a representative wetland system and solved key problems that enable better incorporation of iron-oxidizing microbes into hydrobiogeochemical models.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Remotely-Controlled Shear for Dismantling Highly Radioactive Tools In Rokkasho Vitrification Facility - 12204

A high-level liquid waste vitrification facility in the Japanese Rokkasho Reprocessing Plant (RRP) is right in the middle of hot commissioning tests toward starting operation in fall of 2012. In these tests, various tools were applied to address issues occurring in the vitrification cell. Because of these tools' unplanned placement in the cell it has been necessary to dismantle and dispose of them promptly. One of the tools requiring removal is a rod used in the glass melter to improve glass pouring. It is composed of a long rod made of Inconel 601 or 625 and has been highly contaminated. In order to dismantle these tools and to remotely put them in a designated waste basket, a custom electric shear machine was developed. It was installed in a dismantling area of the vitrification cell by remote cranes and manipulators and has been successfully operated. It can be remotely dismantled and placed in a waste basket for interim storage. This is a very good example of a successful deployment of a specialty remote tool in a hot cell environment. This paper also highlights how commissioning and operations are done in the Japanese Rokkasho Reprocessing Plant. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Particle control near reticle and optics using showerhead

A method and an apparatus to protect a reticle against particles and chemicals in an actinic EUV reticle inspection tool are presented. The method and apparatus utilizes a pair of porous metal diffusers in the form of showerheads to provide a continual flow of clean gas. The main showerhead bathes the reticle surface to be inspected in smoothly flowing, low pressure gas, isolating it from particles coming from surrounding volumes. The secondary showerhead faces away from the reticle and toward the EUV illumination and projection optics, supplying them with purge gas while at the same time creating a buffer zone that is kept free of any particle contamination originating from those optics.

36 MATERIALS SCIENCE↗
DOE OSTI2012

DECOMMISSIONING AND ENVRIONMENTAL CLEANUP OF SMALL ARMS TRAINING FACILITY

USDOE performed a (CERCLA) non-time critical removal (NTCR) action at the Small Arms Training Area (SATA) Site Evaluation Area (SEA) located at the Savannah River Site (SRS), in Aiken, South Carolina. From 1951 to May 2010, the SATA was used as a small weapons practice and qualifying firing range. The SATA consisted of 870.1 ha (2,150 ac) of woodlands and open field, of which approximately 2.9 ha (7.3 ac) were used as a firing range. The SATA facility was comprised of three small arms ranges (one static and two interactive), storage buildings for supplies, a weapons cleaning building, and a control building. Additionally, a 113- m (370-ft) long earthen berm was used as a target backstop during live-fire exercises. The berm soils accumulated a large amount of spent lead bullets in the berm face during the facilities 59- years of operation. The accumulation of lead was such that soil concentrations exceeded the U.S. Environmental Protection Agency (USEPA) residential and industrial worker regional screening levels (RSLs). The RSL threshold values are based on standardized exposure scenarios that estimate contaminant concentrations in soil that the USEPA considers protective of humans over a lifetime. For the SATA facility, lead was present in soil at concentrations that exceed both the current residential (400 mg/kg) and industrial (800 mg/kg) RSLs. In addition, the concentration of lead in the soil exceeded the Toxicity Characteristic Leaching Procedure (TCLP) (40 Code of Federal Regulations [CFR] 261.24) regulatory limit. The TCLP analysis simulates landfill conditions and is designed to determine the mobility of contaminants in waste. In addition, a principal threat source material (PTSM) evaluation, human health risk assessment (HHRA), and contaminant migration (CM) analysis were conducted to evaluate soil contamination at the SATA SEA. This evaluation determined that there were no contaminants present that constitute PTSM and the CM analysis revealed that no constituents posed a migration risk to groundwater. The NTCR action involved removal of approximately 12,092 m3 (15,816 yd3) of spent bullets and lead-impacted soil and off-site disposal. The removal action included soils from the berm area, a fill area that received scraped soils from the berm, and soil from a drainage ditch located on the edge of the berm area. Also included in the removal action was a mixture of soil, concrete, and asphalt from the other three range areas. Under this action, 11,796 m3 (15,429 yd3) of hazardous waste and impacted soil were removed from the SATA and transported to a permitted hazardous waste disposal facility (Lone Mountain Facility in Oklahoma) and 296 m3 (387 yd3) of nonhazardous waste (primarily concrete debris) were removed and transported to a local solid waste landfill for disposal. During the excavation process, the extent was continuously assessed through the use of a hand-held, field-portable X-ray fluorescence unit with results verified using confirmation sampling with certified laboratory analysis. Following the completion of the excavation and confirmation sampling, final contouring, grading, and establishment of vegetative cover was performed to stabilize the affected areas. The NTCR action began on August 17, 2010, and mechanical completion was achieved on April 27, 2011. The selected removal action met the removal action objectives (RAOs), is protective of human health and the environment both in the short- and long-term, was successful in removing potential ecological risks, and is protective of surface water and groundwater. Furthermore, the selected NTCR action met residential cleanup goals and resulted in the release of the SEA from restricted use contributing to the overall footprint reduction at SRS.

54 ENVIRONMENTAL SCIENCES↗