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At least 1,801 records · Page 100

Code Validation of SAM Using Forced and Natural Circulation Data from NACIE-UP Benchmark

Heavy liquid metals (HLMs) are promising candidates as coolants of Generation IV fast reactors due to their thermophysical properties. In the last decade, experimental work has been proposed as part of research and development efforts to develop such systems. In this context, researchers from the Brasimone Research Center have conducted many experiments using the Natural Circulation Experiment Upgrade (NACIE-UP) facility to study the thermofluid dynamic behavior of HLMs in rod bundle configurations with or without wire wrappers. This facility consists of a rectangular loop operated with lead-bismuth eutectic. Sensors across the loop monitor relevant parameters, i.e. temperatures, heat transfer, and flow conditions. Here, in the present work, we carefully select published data from NACIE-UP to validate the System Analysis Module (SAM), a modern system analysis code developed at Argonne National Laboratory. We developed one SAM model using specifications of the facility geometry and materials existing in relevant papers and reports. On top of that, these references provided the boundary conditions for simulating natural circulation and forced convection experiments in either steady or transient conditions. The SAM model simulates five test cases with diverse operating conditions. Ultimately, the code is proven to predict temperatures and mass flow rates that closely match the experiments. The discrepancies between numerical predictions and diverse transients are limited to a few degrees Celsius, showcasing that SAM is well suited for analyzing nuclear systems relying on HLM coolants.

advanced reactors↗

Targeted Dy intercalation under graphene/SiC for tuning its electronic band structure

Metal intercalation of graphene is a promising method to tune its electronic band structure and generate novel electronic and topological phases. The tuning depends critically on the ability to bond the intercalated atoms at predesigned, subsurface interlayer locations because the emerging band structure depends on metal location. In this work, we have studied Dy intercalation under single-layer graphene (SLG) on SiC using spot profile analysis–low-energy electron diffraction and scanning tunneling microscopy (STM). The experimental work is complemented with density-functional theory (DFT) analysis. Because different diffraction spots originate from different subsurface interlayer regions, it is possible to identify changes in the intercalation location by monitoring the spot intensity as a function of growth conditions. DFT calculations of the chemical potential as a function of intercalated Dy coverage support the variation of the stability of the intercalated phase at different intercalated locations. The preferred location is confirmed from STM studies showing the removal of the 6 × 6 moiré corrugation at the preferred location, observed at higher Dy coverage.

2-dimensional systems↗

Advanced Instrumentation for Extreme Environments

The Department of Energy (DOE) Office of Nuclear Energy (NE) is pursuing embedded instrumentation and controls (I&C) technology for next generation nuclear power generation applications. Embedded systems encompass a wide range of configurations and technologies; we define embedding in this instance as the integration of the sensors and the control system design into the component design using a systems engineering process. Embedded I&C systems are often an essential part of developing new capabilities, improving reliability, enhancing performance, and reducing operational costs. The new intrinsically safe, more efficient, and cost effective reactor technologies (Next Generation Nuclear Plant and Small Modular Reactors) require the development and application of new I&C technologies. These new designs raise extreme environmental challenges such as high temperatures (over 700 C) and material compatibility (e.g., molten salts). The desired reliability and functionality requires measurements in these extreme conditions including high radiation environments which were not previously monitored in real time. The DOE/NE Nuclear Energy Enabling Technologies (NEET) program currently has several projects investigating I&C technologies necessary to make these reactor designs realizable. The project described in this paper has the specific goal of investigating embedded I&C with the following objectives: 1.Explore and quantify the potential gains from embedded I&C improved reliability, increased performance, and reduced cost 2.Identify practical control, sensing, and measurement techniques for the extreme environments found in high-temperature reactors 3.Design and fabricate a functional prototype high-temperature cooling pump for molten salts represents target demonstration of improved performance, reliability, and widespread usage There are many engineering challenges in the design of a high-temperature liquid salt cooling pump. The pump and motor are in direct contact with molten fluoride salt at 700 C (1,292 F) as part of a reactor cooling loop. The motor-pump combination during normal operation would be red-hot (Figure 1). This environment challenges every facet of the design including seals, wiring, magnetic materials, and sensors. In this paper, we discuss the challenges of sensor design in extreme environments and specifically the sensor design for a high-temperature fluoride salt coolant pump. This pump will be used as a test-bed for embedded I&C development and validation in extreme environments.

Extreme Environments↗

Sustained Ability of a Natural Microbial Community to Remove Nitrate from Groundwater

Abstract Microbial‐mediated nitrate removal from groundwater is widely recognized as the predominant mechanism for nitrate attenuation in contaminated aquifers and is largely dependent on the presence of a carbon‐bearing electron donor. The repeated exposure of a natural microbial community to an electron donor can result in the sustained ability of the community to remove nitrate; this phenomenon has been clearly demonstrated at the laboratory scale. However, in situ demonstrations of this ability are lacking. For this study, ethanol (electron donor) was repeatedly injected into a groundwater well (treatment) for six consecutive weeks to establish the sustained ability of a microbial community to remove nitrate. A second well (control) located upgradient was not injected with ethanol during this time. The treatment well demonstrated strong evidence of sustained ability as evident by ethanol, nitrate, and subsequent sulfate removal up to 21, 64, and 68%, respectively, as compared to the conservative tracer (bromide) upon consecutive exposures. Both wells were then monitored for six additional weeks under natural (no injection) conditions. During the final week, ethanol was injected into both treatment and control wells. The treatment well demonstrated sustained ability as evident by ethanol and nitrate removal up to 20 and 21%, respectively, as compared to bromide, whereas the control did not show strong evidence of nitrate removal (5% removal). Surprisingly, the treatment well did not indicate a sustained and selective enrichment of a microbial community. These results suggested that the predominant mechanism(s) of sustained ability likely exist at the enzymatic‐ and/or genetic‐levels. The results of this study demonstrated the in situ ability of a microbial community to remove nitrate can be sustained in the prolonged absence of an electron donor.

54 ENVIRONMENTAL SCIENCES↗

Compilation of a Solar Mirror Materials Database and an Analysis of Natural and Accelerated Mirror Exposure and Degradation

The National Renewable Energy Laboratory (NREL) has been conducting exposure experiments on solar reflectors for over four decades. Thousands of mirror samples from over one hundred suppliers have been exposed to and monitored in a range of relevant environments. These test conditions include outdoor test settings and several controlled laboratory environments. These samples have been rigorously individually characterized using a series of reflectance measurements, visual inspections, and in some cases, in-depth composition analysis to identify degradation modes, reflectance losses, and other mirror properties integral to understanding the solar reflector's life cycle. Here, this paper compiles the decades of measurement data into a concise statistical analysis. It includes exposure and degradation data for numerous reflector types, including secondary-surface reflector permutations of polymer and glass superstrates with silver and aluminum reflectors as well as front-surface reflectors. The results herein are intended to analyze environmental stressors and degradation trends among various historical and state-of-the-art solar reflectors. It may be used to support solar reflector design, effective testing methodology, and inform manufacturing decisions moving forward. Presented are the results of the compiled database and an initial analysis for degradation rate modeling using full-spectrum and wavelength-dependent approaches. The database is a growing resource hosted on a live, publicly accessible website. In conjunction with the analysis presented here, it provides a valuable resource to the solar reflector manufacturing and testing industry.

14 SOLAR ENERGY↗

A Comparison of Adaptive and Template Matching Techniques for Radio-Isotope Identification

We compare and contrast the effectiveness of a set of adaptive and non-adaptive algorithms for isotope identi cation based on gamma-ray spectra. One dimensional energy spectra are simulated for a variety of dwell-times and source to detector distances in order to reflect conditions typically encountered in radiological emergency response and environmental monitoring applications. We nd that adaptive methods are more accurate and computationally efficient than non-adaptive in cases of operational interest.

97 MATHEMATICS AND COMPUTING↗

Evolution of anatase surface active sites probed by in situ sum-frequency phonon spectroscopy

Surface active sites of crystals often govern their relevant surface chemistry, yet to monitor them in situ in real atmosphere remains a challenge. Using surface-specific sum-frequency spectroscopy, we identified the surface phonon mode associated with the active sites of undercoordinated titanium ions and conjoint oxygen vacancies, and used it to monitor them on anatase (TiO 2 ) (101) under ambient conditions. In conjunction with theory, we determined related surface structure around the active sites and tracked the evolution of oxygen vacancies under ultraviolet irradiation. We further found that unlike in vacuum, the surface oxygen vacancies, which dominate the surface reactivity, are strongly regulated by ambient gas molecules, including methanol and water, as well as weakly associated species, such as nitrogen and hydrogen. The result revealed a rich interplay between prevailing ambient species and surface reactivity, which can be omnipresent in environmental and catalytic applications of titanium dioxides.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Methodology for Risk-informed O&M decision making in power plants

Incorporation of real-time component information using equipment condition assessment (ECA) through the development of enhanced risk monitors (ERM) for active components in advanced reactor (AR) and advanced small modular reactor (SMR) designs. We incorporate time-dependent failure probabilities from prognostic health management (PHM) systems to dynamically update the risk metric of interest. This information is used to augment data used for supervisory control and plant-wide coordination of multiple modules by providing the incremental risk incurred due to aging and demands placed on components that support mission requirements.

Source record↗

An Instrumented Capsule Design to Measure Thermal Conductivity in Miniature UO2 Specimens

Numerous separate effects irradiations of miniature nuclear fuel specimens have been conducted in the High Flux Isotope Reactor (HFIR) under the experimental platform designated as MiniFuel. MiniFuel is a static irradiation capability in which microstructural evolution and fuel performance phenomena are observed during postirradiation examination thereby offering a snapshot of the terminal fuel characteristics. This approach inherently requires fielding an irradiation where the experimental conditions are determined using predictive models and the pertinent outcomes are measured at the end of the test. Static irradiations can provide useful insights to the relationships between fuel performance and the pivotal irradiation conditions, namely temperature and burnup, but the ability to monitor fuel performance in situ would further support fuel development and qualification. To this end, an instrumented experiment design is being developed at Oak Ridge National Laboratory to capture thermal conductivity degradation and fission gas release during HFIR irradiation. These phenomena will be monitored using unique capsule designs that each target a different phenomenon. This paper details the thermal conductivity capsule (TCC) design and its expected performance envelope as determined using computer models. Each TCC will contain a miniature UO2 disc specimen (~0.5 mm thick × 5 mm diameter) sandwiched between metallic slugs with embedded thermocouples. The coupling of in situ temperature measurements, known thermal conductivity of the metallic components, and heat generation rates computed using high-fidelity neutronics models make the thermal conductivity measurement possible. This paper describes the reactor physics and heat transfer models used to predict the capsule’s performance and the methodology for calculating the fuel specimen’s thermal conductivity from the thermocouple measurements.

Gorton, Jacob [ORNL] (ORCID:0000000269806083)↗

Imagine Homes New Construction Occupied Test House

This report summarizes the research findings of a long-term monitoring plan to evaluate the performance of an energy-efficient home constructed in 2010 in San Antonio, Texas. Monitoring of the energy use, energy generation, and temperature conditions for this project occurred between July 2010 and October 2011. The heating, ventilation, and air conditioning system effectively maintained acceptable temperatures and humidity levels in peak cooling and heating and non-peak operating periods. Discrepancies were found between modeled and actual energy use values, with actual space cooling energy use closest to the corresponding modeled value. Energy consumption predicted for lighting, appliances, and miscellaneous electrical loads was significantly higher than measured amounts, and energy consumption predicted for cooling was significantly lower than measured amounts. A high amount of the 1,600 kWh of PV-generated electricity produced annually was sent to the electric grid every month. The solar thermal DHW system was the main source of hot water for most of the year and performed well; during summer, electrical use by the backup system was rare.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Imagine Homes New Construction Occupied Test House

This report summarizes the research findings of a long-term monitoring plan to evaluate the performance of an energy-efficient home constructed in 2010 in San Antonio, Texas. Monitoring of the energy use, energy generation, and temperature conditions for this project occurred between July 2010 and October 2011. The home achieves a source energy savings of 32% without the installed photovoltaic (PV) system and 44% savings with the PV system contribution relative to the Building America House Simulation Protocols. This report summarizes the research findings related to heating, ventilation, and air conditioning system performance, estimated and actual energy use of key subsystems, electricity generation by the PV system, and performance of the solar thermal domestic hot water system.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Advanced Fuel Cycle Cost Basis – 2017 Edition

This report, commissioned by the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the DOE Nuclear Technology Research and Development (NTRD) Program (previously the Fuel Cycle Research and Development (FCRD) and the Advanced Fuel Cycle Initiative (AFCI)). The report describes the NTRD cost basis development process, reference information on NTRD cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for numerous fuel cycle cost modules (modules A-O) as well as cost modules for a number of reactor types (R modules). The fuel cycle cost modules were developed in the areas of natural uranium mining and milling, thorium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, managed decay storage, recycled product storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, transuranic, and high-level waste. Since its inception, this report has been periodically updated. The last such internal document was published in August 2015 while the last external edition was published in December of 2009 as INL/EXT-07-12107 and is available on the Web at URL: www.inl.gov/technicalpublications/Documents/4536700.pdf. This current report (Sept 2017) is planned to be reviewed for external release, at which time it will replace the 2009 report as an external publication. This information is used in the ongoing evaluation of nuclear fuel cycles by the NE NTRD program.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Multiyear Analysis of the Fate and Transport of Contaminated Soils at Plutonium Valley and the Smoky Site, Nevada National Security Site

Desert Research Institute (DRI) has collected approximately 10 years of atmospheric and hydrologic data at Plutonium Valley and the Smoky Site on the Nevada National Security Site to identify the potential for radionuclide-contaminated soils to be transported via wind and water. Plutonium preferentially binds to finer soil particles (Shinn et al., 1993; Miller et al., 2015), which can be transported through erosion processes. Data collected by DRI are used to determine the mechanisms and thresholds that result in the transport of radionuclide-contaminated soils, and climate model projections are used to understand how these mechanisms may change in the future. This work will help identify the parameters and threshold conditions that should be incorporated into post-closure monitoring plans for these and other Soils Corrective Action Unit (CAU) sites.

54 ENVIRONMENTAL SCIENCES↗

Collider Physics Instrumentation

We are developing new technologies for particle tracking. These include 3D silicon sensors and devices for calibration and dosimetry in the HL-LHC fluence regime. We collaborate in the development of a new model for radiation damage in silicon - this is immediately relevant to extrapolations about the future of LHC tracker hardware. We lead radiation damage campaigns on behalf of many collaborating LHC institutes as well as ourselves, and we apply the results of these to development of new techniques for particle beam monitoring and operation of silicon detectors in variable environmental conditions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Southeast Regional Carbon Sequestration Partnership (SECARB) Preparation of Discontinuation Plan

In some CO 2 injection demonstration projects, the injection is planned as a stand-along activity, that may require a final extensive phase for planning for demobilization. The first step toward demobilization is making decisions about when the project is completed in terms of achieving milestones. After this, the project may have a task of satisfying regulators and funding partners that the injected CO 2 , elevated pressure, and well construction have a reached a condition which is acceptable for abandonment. In some projects the condition for closure has been conceptualized as “plume stabilization”; other projects have proposed extracting CO 2 . When agreement on the required conditions are reached, the needed actions are completed, whether monitoring the trend toward stabilization and pressure re-equilibration or undertaking more active processes. At the time defined in the demobilization process, wells and other infrastructure are closed and remediated following processes defined by the demobilization process. At some point, closure of the project is accomplished; in some cases, activities needed for various length of time are described as post-closure care.

01 COAL, LIGNITE, AND PEAT↗

Evaluating Tools and Technologies for Monitoring Baleen Whales During Offshore Wind Foundation Installation

Impacts to baleen whales are of particular concern in the context of offshore wind development because of their conservation status, the overlap of their habitat with current and planned offshore wind energy facilities, and their expected sensitivity to low-frequency sounds, such as those produced during pile driving. Therefore, this report focuses on monitoring technologies capable of detecting this species group. The scope of this report is to assess the current state of technologies and methods for monitoring baleen whales in low- and no-light conditions in conjunction with offshore wind foundation installation. This work considers the performance of various sensing technologies that can be used to observe the presence of baleen whales near offshore construction activities. The scope of work includes: 1. Technology Performance Metrics – Identify metrics that can be used to assess technology performance. 2. Technology Evaluation – Synthesize the past performance of technologies with respect to the performance metrics based on available literature. 3. Technology Characterization Framework – Describe a potential framework to characterize technology performance with a standardized approach. 4. Technology Research and Development Needs – Identify future needs and opportunities for research, development, and deployment to improve technologies.

17 WIND ENERGY↗

CRADA Number NFE-24-10495 with Algaeo, LLC (CRADA Final Report)

This study investigated the potential for a synthetic consortium of mutualistic terrestrial microbes— comprising the fungi Laccaria bicolor and Serendipita indica alongside bacterial Pseudomonas strains—to influence the growth and productivity of the freshwater microalgae Chlorella vulgaris. The project aimed to determine if microbial complexes engineered to enhance terrestrial plant growth could provide similar growth-promoting benefits or pathogen resistance within an aquatic algal system. Using a quantitative experimental design, C. vulgaris was co-cultured with the microbial mix under controlled laboratory conditions, with growth rates, biomass density, and metabolic activity monitored over a standard cultivation period. The results demonstrated no significant symbiotic relationship or growth enhancement between these terrestrial microbes and the microalgae, as the C. vulgaris maintained independent growth trajectories unaffected by the fungal or bacterial inoculants. We conclude that the specialized mutualisms of these fungi and bacteria are likely niche-specific to vascular plants and do not readily translate to the phycosphere of C. vulgaris. These findings are valuable to synthetic biologists and bioenergy researchers, as they define the functional boundaries of inter-kingdom microbial engineering and underscore the necessity of selecting niche-compatible species when designing consortia for industrial algal cultivation.

60 APPLIED LIFE SCIENCES↗

Arsenic Exposure Causes Global Changes in the Metalloproteome of Escherichia coli

Arsenic is a toxic metalloid with differential biological effects, depending on speciation and concentration. Trivalent arsenic (arsenite, AsIII) is more toxic at lower concentrations than the pentavalent form (arsenate, AsV). In E. coli, the proteins encoded by the arsRBC operon are the major arsenic detoxification mechanism. Our previous transcriptional analyses indicate broad changes in metal uptake and regulation upon arsenic exposure. Currently, it is not known how arsenic exposure impacts the cellular distribution of other metals. This study examines the metalloproteome of E. coli strains with and without the arsRBC operon in response to sublethal doses of AsIII and AsV. Size exclusion chromatography coupled with inductively coupled plasma mass spectrometry (SEC-ICPMS) was used to investigate the distribution of five metals (56Fe, 24Mg, 66Zn, 75As, and 63Cu) in proteins and protein complexes under native conditions. Parallel analysis by SEC-UV-Vis spectroscopy monitored the presence of protein cofactors. Together, these data reveal global changes in the metalloproteome, proteome, protein cofactors, and soluble intracellular metal pools in response to arsenic stress in E. coli. This work brings to light one outcome of metal exposure and suggests that metal toxicity on the cellular level arises from direct and indirect effects.

59 BASIC BIOLOGICAL SCIENCES↗

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