Office of Nuclear Energy
governmentWashington, District of Columbia, United States
Research output, citation impact, and the most-cited recent papers from Office of Nuclear Energy (United States). Aggregated across the NobleBlocks index of 300M+ scholarly works.
Top-cited papers from Office of Nuclear Energy
Basic meteorological concepts are covered as well as plume rise, source effects, and diffusion models. Chapters are included on cooling tower plumes and urban diffusion. Suggestions are given for calculating diffusion in special situations, such as for instantaneous releases over complex terrain, over long distances, and during times when chemical reactions or dry or wet deposition are important. (PSB)
A new cluster-analysis method, the bond energy algorithm, has been developed recently; it operates upon a raw input object-object or object-attribute data array by permuting its rows and columns in order to find informative variable groups and their interrelations. This paper describes the algorithm and illustrates by several examples its use for both problem decomposition and data reorganization.
Variation and tradeoffs within and among plant traits are increasingly being harnessed by empiricists and modelers to understand and predict ecosystem processes under changing environmental conditions. While fine roots play an important role in ecosystem functioning, fine-root traits are underrepresented in global trait databases. This has hindered efforts to analyze fine-root trait variation and link it with plant function and environmental conditions at a global scale. This Viewpoint addresses the need for a centralized fine-root trait database, and introduces the Fine-Root Ecology Database (FRED, http://roots.ornl.gov) which so far includes > 70 000 observations encompassing a broad range of root traits and also includes associated environmental data. FRED represents a critical step toward improving our understanding of below-ground plant ecology. For example, FRED facilitates the quantification of variation in fine-root traits across root orders, species, biomes, and environmental gradients while also providing a platform for assessments of covariation among root, leaf, and wood traits, the role of fine roots in ecosystem functioning, and the representation of fine roots in terrestrial biosphere models. Continued input of observations into FRED to fill gaps in trait coverage will improve our understanding of changes in fine-root traits across space and time.
The functional anatomy of visually guided movement was investigated in 18 normal subjects performing visuomotor tracking tasks during positron emission tomography imaging. Tracking a moving target with the index finger defined a network of focal responses of relative cerebral blood flow (relCBF) located in the primary motor cortex, dorsal parietal cortex, precuneate cortex, supplementary motor area (SMA) and ipsilateral anterior cerebellum relative to visual tracking alone. When the temporal complexity of the tracking task was altered by introducing a 'no go' contingency that allowed for greater time for movement preparation, there was a significant increase of relCBF in the SMA (P less than 0.0001). When the spatial complexity was augmented by adding a secondary target that provided directional cues for the primary target, there were additional significant increases of relCBF in bilateral dorsal parietal cortex (P less than 0.05) and precuneate cortex (P less than 0.05). Although the cued 'no go' task was subjectively easier, relCBF responses were similar to the uncued 'no go' task in motor areas. Performing the tracking task with different body parts produced somatotopically distributed responses in only the motor cortex. The findings are concordant with clinical reports of patients with brain lesions and physiological evidence that identifies this distributed network for performing visually guided movement. The results provide direct human evidence in the normal brain that the supplementary motor area contributes in part to the sequencing of movements and the medial and dorsal parietal cortex participates in the integration of spatial attributes during selection of movements.
The Thermal Analysis Research Program (TARP) has been developed as a research tool for the thermal analysis of buildings. It especially aims to study the interactions of many complex heat transfer phenomena. TARP uses the detailed heat balance method for the simultaneous calculation of the energy requirements of multiple rooms. Interroom conductive and convective processes are simulated in detail. This program reference manual describes the algorithms, input, output, and program structure of TARP. The program is written to be portable and modifiable. It is written in FORTRAN 77 and has run on CDC and UNIVAC computers.
PURPOSE: The search for ideal protective agents for use in a variety of radiation scenarios has continued for more than six decades. This review evaluates agents and procedures that have the potential to protect against acute and late effects of ionising radiation when administered either before or after radiation exposure. CONCLUSION: Over the years, extensive experimental studies of radiation-protective agents have enhanced our knowledge of radiation physics, chemistry, and biology. However, translation of agents from animal testing to use in various scenarios, such as prophylactic adjuncts in radiotherapy or post-exposure treatments for potential victims of radiation accidents/incidents, has been slow. Nevertheless, a number of compounds are now available for use in a variety of radiation situations. These include agents approved by the U.S. Food and Drug Administration for use in reducing exposure to internal radionuclides (Prussian blue, calcium diethylenetriamene pentaacetate (DTPA) and zinc DTPA, potassium iodide) and amifostine for alleviating xerostomia associated with radiotherapy. Consensus groups have also recommended other therapies such as granulocyte colony-stimulating factor for radiation-induced neutropenia. The variety of prophylactic and therapeutic agents in the research pipeline includes those that are naturally-occurring with low toxicity, provide a long window of protection, protect normal tissue while sensitising tumours, or act via receptors and modulate biological processes such as induction of genes responsible for radioresistance. The search for agents that protect against acute and late effects of ionising radiation injury will undoubtedly continue into the future and influence other areas of radiation research.
The supply side of an oligopolistic market supplying a homogeneous product noncooperatively is modeled. In this market, there is one leader and N followers. The followers operate under the Cournot assumption of zero conjectural variation and are accordingly called Cournot firms. The leader, called a Stackelberg firm, specifically takes into account the reaction of the Cournot firms to its output. For this situation, we study the behavior and implications of the joint Cournot reaction curve as generated by plausible economic market assumptions. In particular, we study the existence and uniqueness of a Stackelberg-Nash-Cournot equilibrium. In addition, we prescribe an efficient algorithm to determine a set of equilibrating output quantities for the firms.
Abstract Life cycle assessment (LCA) analysts are increasingly being asked to conduct life cycle‐based systems level analysis at the earliest stages of technology development. While early assessments provide the greatest opportunity to influence design and ultimately environmental performance, it is the stage with the least available data, greatest uncertainty, and a paucity of analytic tools for addressing these challenges. While the fundamental approach to conducting an LCA of emerging technologies is akin to that of LCA of existing technologies, emerging technologies pose additional challenges. In this paper, we present a broad set of market and technology characteristics that typically influence an LCA of emerging technologies and identify questions that researchers must address to account for the most important aspects of the systems they are studying. The paper presents: (a) guidance to identify the specific technology characteristics and dynamic market context that are most relevant and unique to a particular study, (b) an overview of the challenges faced by early stage assessments that are unique because of these conditions, (c) questions that researchers should ask themselves for such a study to be conducted, and (d) illustrative examples from the transportation sector to demonstrate the factors to consider when conducting LCAs of emerging technologies. The paper is intended to be used as an organizing platform to synthesize existing methods, procedures and insights and guide researchers, analysts and technology developer to better recognize key study design elements and to manage expectations of study outcomes.
Abstract Observations of climate change during the CMIP5 extended historical period (1850–2012) are compared to trends simulated by six versions of the NASA Goddard Institute for Space Studies ModelE2 Earth System Model. The six models are constructed from three versions of the ModelE2 atmospheric general circulation model, distinguished by their treatment of atmospheric composition and the aerosol indirect effect, combined with two ocean general circulation models, HYCOM and Russell. Forcings that perturb the model climate during the historical period are described. Five‐member ensemble averages from each of the six versions of ModelE2 simulate trends of surface air temperature, atmospheric temperature, sea ice and ocean heat content that are in general agreement with observed trends, although simulated warming is slightly excessive within the past decade. Only simulations that include increasing concentrations of long‐lived greenhouse gases match the warming observed during the twentieth century. Differences in twentieth‐century warming among the six model versions can be attributed to differences in climate sensitivity, aerosol and ozone forcing, and heat uptake by the deep ocean. Coupled models with HYCOM export less heat to the deep ocean, associated with reduced surface warming in regions of deepwater formation, but greater warming elsewhere at high latitudes along with reduced sea ice. All ensembles show twentieth‐century annular trends toward reduced surface pressure at southern high latitudes and a poleward shift of the midlatitude westerlies, consistent with observations.
ABSTRACT The installed capacity of photovoltaic (PV) systems has recently increased at a much faster rate than the development of grid codes to effectively and efficiently manage high penetrations of PV within the distribution system. In a number of countries, PV penetrations in some regions are now raising growing concerns regarding integration. Management strategies vary considerably by country—some still have an approach that PV systems should behave as passive as possible, whereas others demand an active participation in grid control. This variety of grid codes also causes challenges in learning from “best practice.” This paper provides a review of current grid codes in some countries with high PV penetrations. In addition, the paper presents a number of country‐specific case studies on different approaches for improved integration of PV systems in the distribution grid. In particular, we consider integration approaches using active and reactive power control that can reduce or defer expensive grid reinforcement while supporting higher PV penetrations. Copyright © 2011 John Wiley & Sons, Ltd.
Abstract Development of reliable source emission inventories is particularly needed to advance the understanding of the origin of Arctic haze using chemical transport modeling. This study develops a regional anthropogenic black carbon (BC) emission inventory for the Russian Federation, the largest country by land area in the Arctic Council. Activity data from combination of local Russia information and international resources, emission factors based on either Russian documents or adjusted values for local conditions, and other emission source data are used to approximate the BC emissions. Emissions are gridded at a resolution of 0.1° × 0.1° and developed into a monthly temporal profile. Total anthropogenic BC emission of Russia in 2010 is estimated to be around 224 Gg. Gas flaring, a commonly ignored black carbon source, contributes a significant fraction of 36.2% to Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 25.0%, 20.3%, 13.1%, and 5.4%, respectively. Three major BC hot spot regions are identified: the European part of Russia, the southern central part of Russia where human population densities are relatively high, and the Urals Federal District where Russia's major oil and gas fields are located but with sparse human population. BC simulations are conducted using the hemispheric version of Community Multi‐scale Air Quality Model with emission inputs from a global emission database EDGAR (Emissions Database for Global Atmospheric Research)‐HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR‐HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulation using the new Russian BC emission inventory could improve 30–65% of absorption aerosol optical depth measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four ground monitoring sites (Zeppelin, Barrow, Alert, and Tiksi) in the Arctic Circle, surface BC simulations are improved the most during the Arctic haze periods (October–March). The poor performance of Arctic BC simulations in previous studies may be partly ascribed to the Russian BC emissions built on out‐of‐date and/or missing information, which could result in biases to both emission rates and the spatial distribution of emissions. This study highlights that the impact of Russian emissions on the Arctic haze has likely been underestimated, and its role in the Arctic climate system needs to be reassessed. The Russian black carbon emission source data generated in this study can be obtained via http://abci.ornl.gov/download.shtml or http://acs.engr.utk.edu/Data.php .
A 871-base pair cDNA encoding the human N-methylpurine-DNA glycosylase (MPG) was cloned from a HeLa S3 cDNA expression library in a pUC vector by phenotypic screening of MPG-negative (tag- alkA-) Escherichia coli cells exposed to methylmethane sulfonate. The active MPG is expressed as a 31-kDa fusion protein. The human cDNA-encoded MPG releases 3-methyladenine, 7-methylguanine, and 3-methylguanine from DNA and thus has a substrate range similar to that of the indigenous enzyme and the E. coli AlkA protein. The cDNA hybridizes with distinct restriction fragments of mammalian DNAs but not with E. coli or yeast DNA. A search in the GenBank data bank failed to show any other cloned DNA with a similar sequence. Although the human protein has 62% sequence homology with the corresponding rat enzyme, only a few amino acid residues are conserved between the human protein and the E. coli and yeast MPGs. However, a conserved glutamine residue in all MPGs that release 3-alkyladenine and an arginine residue in eukaryotic MPGs and E. coli AlkA that act additionally on N-alkylguanines suggest that these residues are involved in recognition of adenine and guanine adducts in DNA, respectively. Although the 1.1-kilobase mRNAs of MPG from human and rodents are similar in size, liver and cultured cells of rat have much lower levels of MPG mRNA than do human and mouse cells. A hamster cell line variant isolated as being resistant to methylmethane sulfonate does not have a higher level of MPG mRNA than the parent cell line.
The U.S. Department of Energy (DOE) is responsible for retrieving, immobilizing, and disposing of radioactive waste generated during the production of nuclear weapons in the United States. The general strategy for treating the radioactive tank waste consists of pretreating the wastes by separating them into high-level and low-activity fractions. The high-level fraction will be immobilized in a glass form suitable for disposal in a geologic repository. The low-activity waste will be immobilized in a waste form suitable for on-site. This paper reviews recent developments in the application of pretreatment technologies to the processing of the DOE radioactive tank wastes.
A techno-economic analysis of the environmental and economic feasibility of middle distillate fuel production <italic>via</italic> fermentation and advanced fermentation technologies.
This manual describes the procedures and data which are used in the design, construction, and testing of shielding for the reactor plants of the Naval Reactors Program and for the Shippingport Pressurized Water Reactor (PWR). These procedures are quite different from those practiced on other projects. The fact that these techniques-developed originally for naval reactor applications-apply so directly and so well to the PWR makes it apparent that this manu& micht be useful tc other projects outside the Naval Reactors Program. It should not be assumed that careful shield design is important only for mobile reactor plants. Poor shield design in a stationary reactor can lead to high costs, poor maintenance accessibility, high radiation levels near shield penetrations or stiffeners, or excessive stresses due to nuclear heating in structures near the reactor core. Inadequate design of the reactor shield can result in activation of primary coolant equipment, decomposition of water in the heat exchanger (perhaps aggravating corrosion), or radiation damage to the material of the primary shield itself. The detectors upon which the reactor control system depends are designed around fluxes calculated by the shield designer; err o r s here can result in blind reactor start-ups or burned-out detectors. The methods discussed in this manual have two salient features: (1) They have been actually used for, and tested ‘on, real power reactor shields and (2) they form a basic approach rather than a mock-up approach and thus permit design of shields without expensive and time-consuming use of the reactor facilities in which full-scale shielding mock-ups can be made. This manual should simplify and lessen the time required for desigri of power reactor shields. The quintessence of a great deal of practical experience is contained in this manual. Many theoretical methods that looked appealing on paper were found in practice to be of liffle practical value. Most of the difficulty in designing a practical shield comes from the layout, structure, and irregularities of an actual reactor plant and notin the mathematicalanalysis of an idealized reactor concept; these concepts never have any sharp corners, gaps, streaming paths, or clearances. In this regard a fact which
The corrosion behavior of high‐entropy alloys (HEAs) CoCrFeNi 2 and CoCrFeNi 2 Mo 0.25 was investigated in 3.5 wt. percent sodium chloride (NaCl) at 25°C by electrochemical methods. Their corrosion parameters were compared to those of HASTELLOY® C‐276 (UNS N10276) and stainless steel 316L (UNS 31600) to assess the suitability of HEAs for potential industrial applications in NaCl simulating seawater type environments. The corrosion rates were calculated using corrosion current determined from electrochemical experiments for each of the alloys. In addition, potentiodynamic polarization measurements can indicate active, passive, and transpassive behavior of the metal as well as potential susceptibility to pitting corrosion. Cyclic voltammetry (CV) can confirm the alloy susceptibility to pitting corrosion. Electrochemical impedance spectroscopy (EIS) elucidates the corrosion mechanism under studied conditions. The results of the electrochemical experiments and scanning electron microscopy (SEM) analyses of the corroded surfaces revealed general corrosion on alloy CoCrFeNi 2 Mo 0.25 and HASTELLOY C‐276 and pitting corrosion on alloy CoCrFeNi 2 and stainless steel 316L.
Abstract This paper is the summation of several analyses to assess the size and benefits of a Billion Ton Bioeconomy, a vision to enable a sustainable market for producing and converting a billion tons of US biomass to bio‐based energy, fuels, and products by 2030. Two alternative biomass availability scenarios in 2030, defined as the (i) Business‐as‐usual (598 million dry tons) and (ii) Billion Ton (1042 million dry tons), establish a range of possible outcomes for the future bioeconomy. The biomass utilized in the current (2014) (365 million dry tons) economy is estimated to displace approximately 2.4% of fossil energy consumption and avoid 116 million tons of CO 2 ‐equivalent ( CO 2 e ) emissions, whereas the Billion Ton bioeconomy of 2030 could displace 9.5% of fossil energy consumption and avoid as much as 446 million tons of CO 2 equivalent emissions annually. Developing the integrated systems, supply chains, and infrastructure to efficiently grow, harvest, transport, and convert large quantities of biomass in a sustainable way could support the transition to a low‐carbon economy. Bio‐based activities in the current (2014) economy are estimated to have directly generated more than $48 billion in revenue and 285 000 jobs. Our estimates show that developing biomass resources and addressing current limitations to achieve a Billion Ton bioeconomy could expand direct bioeconomy revenue by a factor of 5 to contribute nearly $259 billion and 1.1 million jobs to the US economy by 2030. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd
The DOE Hydrogen Program Plan provides a strategic view of how the Department conducts and coordinates hydrogen research, development, and demonstration (RD&D) activities under the DOE Hydrogen Program. With participation from the Offices of Energy Efficiency and Renewable Energy, Fossil Energy, Nuclear Energy, Electricity, Science, and ARPA-E, the DOE Hydrogen Program is a coordinated Departmental effort to advance the affordable production, transport, storage, and use of carbon-neutral hydrogen across different sectors of the economy. This version of the Plan updates and expands upon previous versions, including the Hydrogen Posture Plan and the DOE Hydrogen and Fuel Cells Program Plan, and provides a coordinated high-level summary of hydrogen-related activities across DOE.
EMPIRE is a modular system of nuclear reaction codes, comprising various nuclear models, and designed for calculations over a broad range of energies and incident particles. The system can be used for theoretical investigations of nuclear reactions as well as for nuclear data evaluation work. Photons, nucleons, deuterons, tritons, helions (3He), α’s, and light or heavy ions can be selected as projectiles. The energy range starts just above the resonance region in the case of a neutron projectile, and extends up to few hundred MeV for heavy ion induced reactions. The code accounts for the major nuclear reaction models, such as optical model, Coupled Channels and DWBA (ECIS06 and OPTMAN), Multi-step Direct (ORION + TRISTAN), NVWY Multi-step Compound, exciton model (PCROSS), hybrid Monte Carlo simulation (DDHMS), and the full featured Hauser-Feshbach model including width fluctuations and the optical model for fission. Heavy ion fusion cross section can be calculated within the simplified coupled channels approach (CCFUS). A comprehensive library of input parameters based on the RIPL-3 library covers nuclear masses, optical model parameters, ground state deformations, discrete levels and decay schemes, level densities, fission barriers, and γ-ray strength functions. Effects of the dynamic deformation of a fast rotating nucleus can be taken into account in the calculations (BARFIT, MOMFIT). The results can be converted into the ENDF-6 format using the accompanying EMPEND code. Modules of the ENDF Utility Codes and the ENDF Pre-Processing codes are applied for ENDF file verification. The package contains the full EXFOR library of experimental data in computational format C4 that are automatically retrieved during the calculations. EMPIRE contains the resonance module that retrieves data from the electronic version of the Atlas of Neutron Resonances by Mughabghab (not provided with the EMPIRE distribution), to produce resonance section and related covariances for the ENDF-6 formatted files. EMPIRE can be used to determine covariances of the calculated data using either sensitivity matrices along with the KALMAN code or employing Monte Carlo approach to produce model generated covariances. In both cases experimental data can be taken into account, either directly (KALMAN) or by feeding the EMPIRE calculated Monte Carlo modelling covariance as a prior to the least square fitting GANDR system. Publication quality graphs can be obtained using the powerful and flexible plotting package ZVView. Interactive plots with ZVView comparing experimental results with calculations can be produced with ENDVER modules. The backbone of the EMPIRE system are bash-shell UNIX scripts that provide for seamless console operation of EMPIRE on Linux, Mac OS X, and Microsoft Windows with GNU gfortran compiler installed. Additionally, the graphical interface, provides for an easy operation of the system on Linux, Mac OS X and virtual Linux machines running on Microsoft Windows.
Although ocean‐derived aerosols play a critical role in modifying the radiative balance over much of the Earth, their sources are still subject to large uncertainties, concerning not only their total mass flux but also their size distribution and chemical composition. These uncertainties are linked primarily to their source drivers, which is mainly wind speed, but are also linked to other factors, such as the presence of organic compounds in sea spray in addition to sea salt. In order to quantify these uncertainties and identify the larger knowledge gaps, we performed several model runs with online calculation of aerosol sources, removal, and underlying climate. In these simulations, both the direct and indirect aerosol effects on climate are included. The oceanic source of organic aerosols was found to be heavily dependent on the sea‐salt parameterization selected. For only a factor of 2 change in assumed fine‐mode sea‐salt size, a factor of 10 difference in mass emissions was calculated for both sea salt and primary oceanic organics. The annual emissions of oceanic organics were calculated to range from 7.5 to 76 Tg yr ‐1 . The model's performance against remote oceanic measurements was greatly improved when including the high estimates of organics. However, the uncertainty could not be further reduced by bulk sea‐salt measurements alone since most parameterizations tested agree reasonably well with measurements of both the (coarse‐mode‐dominated) sea salt and aerosol optical depth due to large changes in lifetime and optical properties of aerosols when different aerosol sizes are used.