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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 1,783 records · Page 99
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Climate-change effects on soils: Accelerated weathering, soil carbon and elemental cycling

Climate change [i.e., high atmospheric carbon dioxide (CO2) concentrations (≥400 ppm); increasing air temperatures (2-4°C or greater); significant and/or abrupt changes in daily, seasonal, and inter-annual temperature; changes in the wet/dry cycles; intensive rainfall and/or heavy storms; extended periods of drought; extreme frost; heat waves and increased fire frequency] is and will significantly affect soil properties and fertility, water resources, food quantity and quality, and environmental quality. Biotic processes that consume atmospheric CO2, and create organic carbon (C) that is either reprocessed to CO2 or stored in soils are the subject of active current investigations, with great concern over the influence of climate change. In addition, abiotic C cycling and its influence on the inorganic C pool in soils is a fundamental global process in which acidic atmospheric CO2 participates in the weathering of carbonate and silicate minerals, ultimately delivering bicarbonate and Ca2+ or other cations that precipitate in the form of carbonates in soils or are transported to the rivers, lakes, and oceans. Soil responses to climate change will be complex, and there are many uncertainties and unresolved issues. The objective of the review is to initiate and further stimulate a discussion about some important and challenging aspects of climate-change effects on soils, such as accelerated weathering of soil minerals and resulting C and elemental fluxes in and out of soils, soil/geo-engineering methods used to increase C sequestration in soils, soil organic matter (SOM) protection, transformation and mineralization, and SOM temperature sensitivity. This review reports recent discoveries, identifies key research needs, and highlights opportunities offered by the climate-change effects on soils.

accelerated weathering↗
DOE OSTI2013

Reactive Transport of the Uranyl Ion in Soils, Sediments, and Groundwater Systems

Uranium is a ubiquitous trace component in rocks ranging from 1.2 to 1.3 µg g-1 in sedimentary rocks, 2.2 to 15 µg g-1 in granites, and 20 to 120 µg g-1 in phosphates (Langmuir, 1997; Plant et al., 1999). Uranium (U) is released to natural waters in dilute concentrations (generally < 10-7 mole L-1) from the weathering of these sources, with water concentrations in uraniferous geologic terrains, such as the southwestern U.S. (USGS, 2011), being higher (~ 10-6.5 mol L-1). Elevated water-borne concentrations are associated with the weathering of natural ore bodies [~10-6 mol L-1; e.g, (Payne and Airey, 2006)], the extraction and mining of U for armaments (Jiang and Aschner, 2009; WHO, 2001) and nuclear fuels [10-6 to 10-3 mol L-1; (Abdelouas et al., 1999)], and the disposal of waste solids and liquids from nuclear fuels reprocessing and arms production [~ 10-6 to 10-2 mol L-1; e.g., (Wan et al., 2009; Zachara et al., 2007)]. The form of U present in natural waters at high concentration is generally the uranyl ion [e.g., UO22+] which is quite soluble. Groundwater in many parts of the world contains dissolved U originating from natural and anthropogenic sources (ATSDR, 2011; EFSA, 2009). Low levels of dissolved U in drinking water are considered a health concern, causing renal and other effects (Kurttio et al., 2002; Kurttio et al., 2005; Limson Zamora et al., 1998; Nriagu et al., 2012; Raymond-Whish et al., 2007; Selden et al., 2009). The U.S. Environmental Protection Agency has established a regulatory drinking water standard of 30 µg L-1 (1.26 x 10-7 mol L-1) or 30 pCi L-1, whichever is exceeded first. The World Health Organization has recommended an even lower drinking water standard of 15 µg L-1 [6.3 x 10-8 mol L-1; (WHO, 2005)]. Human exposure to U through drinking water is expected to rise as world-wide reliance on groundwater sources increase (ESS, 2010).

Environmental Molecular Sciences Laboratory↗
DOE OSTI2014

Development of the Actinide-Lanthanide Separation (ALSEP) Process

Separating the minor actinide elements (Am and Cm) from acidic high-level raffinates arising from the reprocessing of irradiated nuclear fuel is an important step in closing the nuclear fuel cycle. Most proposed approaches to this problem involve two solvent extraction steps: 1) co-extraction of the trivalent lanthanides and actinides, followed by 2) separation of the actinides from the lanthanides. The objective of our work is to develop a single solvent-extraction process for isolating the minor actinide elements. We report here a solvent containing N,N,N',N'-tetra(2 ethylhexyl)diglycolamide (T2EHDGA) combined with 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) that can be used to separate the minor actinides in a single solvent-extraction process. T2EHDGA serves to co-extract the trivalent actinide and lanthanide ions from nitric acid solution. Switching the aqueous phase chemistry to a citrate buffered solution of N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid at pH 2.5 to 4 results in selective transfer of the actinides to the aqueous phase, thus affecting separation of the actinides from the lanthanides. Separation factors between the lanthanides and actinides are approximately 20 in the pH range of 3 to 4, and the distribution ratios are not highly dependent on the pH in this system.

actinide separation↗
DOE OSTI2015

Persistent Monitoring of Acyclic Low-Level Chemical Effluents in Restricted Areas

Detection of acyclic, transitory low-level chemical releases in restricted areas is not possible for remote sensing. A prototype for near-field stealthy persistent monitoring was developed, including a self-organizing semantic sensor field self-management capability. The capability was focused on nuclear conversion and reprocessing, but the platform and software is general.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

openPMD-viewer

Many simulation software produce data in the form of a set of field values or of a set of particle positions. (one such example is that of particle-in-cell codes, which produce data on the electromagnetic fields that they simulate.) However, each particular software uses its own particular format and layout, for the output data. This makes it difficult to compare the results of different simulation software, or to have a common visualization tool for these results. However, a standardized layout for fields and particles has recently been developed: the openPMD format ( HYPERLINK "http://www.openpmd.org/"www.openpmd.org) This format is open- source, and specifies a standard way in which field data and particle data should be written. The openPMD format is already implemented in the particle-in-cell code Warp (developed at LBL) and in PIConGPU (developed at HZDR, Germany). In this context, the proposed software (openPMD-viewer) is a Python package, which allows to access and visualize any data which has been formatted according to the openPMD standard. This package contains two main components: - a Python API, which allows to read and extract the data from a openPMD file, so as to be able to work with it within the Python environment. (e.g. plot the data and reprocess it with particular Python functions) - a graphical interface, which works with the ipython notebook, and allows to quickly visualize the data and browse through a set of openPMD files. The proposed software will be typically used when analyzing the results of numerical simulations. It will be useful to quickly extract scientific meaning from a set of numerical data.

Lehe, Remi↗
DOE OSTI2016

Integrated Decision-Making Tool to Develop Spent Fuel Strategies for Research Reactors

IAEA Member States operating or having previously operated a Research Reactor are responsible for the safe and sustainable management and disposal of associated radioactive waste, including research reactor spent nuclear fuel (RRSNF). This includes the safe disposal of RRSNF or the corresponding equivalent waste returned after spent fuel reprocessing. One key challenge to developing general recommendations lies in the diversity of spent fuel types, locations and national/regional circumstances rather than mass or volume alone. This is especially true given that RRSNF inventories are relatively small, and research reactors are rarely operated at a high power level or duration typical of commercial power plants. Presently, many countries lack an effective long-term policy for managing RRSNF. This paper presents results of the International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) #T33001 on Options and Technologies for Managing the Back End of the Research Reactor Nuclear Fuel Cycle which includes an Integrated Decision Making Tool called BRIDE (Back-end Research reactor Integrated Decision Evaluation). This is a multi-attribute decision-making tool that combines the Total Estimated Cost of each life-cycle scenario with Non-economic factors such as public acceptance, technical maturity etc and ranks optional back-end scenarios specific to member states situations in order to develop a specific member state strategic plan with a preferred or recommended option for managing spent fuel from Research Reactors.

Beatty, Randy L.↗
DOE OSTI2014

Search for Standard Model $ZH \to \ell^+\ell^-b\bar{b}$ at DØ

We present a search for the Standard Model Higgs boson in the ZH → ℓ + ℓ ₋ $b\bar{b}$ channel, using data collected with the DØ detector at the Fermilab Tevatron Collider. This analysis is based on a sample of reprocessed data incorporating several improve ments relative to a previous published result, and a modified multivariate analysis strategy. For a Standard Model Higgs boson of mass 125 GeV, the expected cross section limit over the Standard M odel prediction is improved by about 5% compared to the previous published results in this c hannel from the DØ Collaboration

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

An Assessment of New Satellite Data Products for the Development of a Long-Term Global Solar Resource at 10-100 km

A project representing an effort to reprocess the NASA based solar resource data sets is reviewed. The effort represented a collaboration between NASA, NOAA, NREL and the SUNY-Albany and aimed to deliver a 10 km resolution, 3-hourly data set spanning from 1983 through near-present. Part of the project was to transition project capability to NREL for annual processing to extend data set. Due to delays in the key input project called ISCCP, we evaluate only Beta versions of this data set and also introduce the potential use of another NASA Langley based cloud data set for the CERES project. The CERES project uses these cloud properties to compute global top-of-atmosphere and surface fluxes at the 1x1 degree resolution. Here, we also briefly discuss these data sets in potential usage for solar resource benchmarking.

14 SOLAR ENERGY↗
DOE OSTI2017

Room temperature electrodeposition of actinides from ionic solutions

Uranic and transuranic metals and metal oxides are first dissolved in ozone compositions. The resulting solution in ozone can be further dissolved in ionic liquids to form a second solution. The metals in the second solution are then electrochemically deposited from the second solutions as room temperature ionic liquid (RTIL), tri-methyl-n-butyl ammonium n-bis(trifluoromethansulfonylimide) [Me.sub.3N.sup.nBu][TFSI] providing an alternative non-aqueous system for the extraction and reclamation of actinides from reprocessed fuel materials. Deposition of U metal is achieved using TFSI complexes of U(III) and U(IV) containing the anion common to the RTIL. TFSI complexes of uranium were produced to ensure solubility of the species in the ionic liquid. The methods provide a first measure of the thermodynamic properties of U metal deposition using Uranium complexes with different oxidation states from RTIL solution at room temperature.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Investigation of Benefits from U/TRU Recycle - Quantification and Comparison to U/Pu Recycle

The recently completed comprehensive evaluation and screening of nuclear fuel cycle options identified a number of potentially promising fuel cycles for R&D that offer what could be considered by decision-makers as having the potential for significant improvement compared to the current U.S. fuel cycle. The fuel cycles that consistently performed the best were recycle fuel cycles that used self-sustaining fast reactors operating with either U/Pu or U/TRU recycle fuel and also included options where the fast reactors provided fissile materials to support operation of thermal reactors. However, based on the evaluation criteria and metrics used in the study, there was no difference in benefit between recycle of U/Pu and U/TRU (where TRU is plutonium and the minor actinides) while there were differences in the challenges for developing and deploying such fuel cycles, with U/TRU recycle being more challenging. This observation prompted the question as to the desirability of pursuing R&D on U/TRU recycle given that there may not be an increase in benefit. As a result, activities have been pursued to further investigate the performance differences between U/Pu and U/TRU recycle based on considering issues beyond those used in the evaluation and screening study to identify, if possible, areas where there are significant benefits of U/TRU recycle compared to U/Pu recycle. These new considerations focused on several areas, but especially on the impact on disposal of the HLW, which in the case of U/Pu recycle contains all of the minor actinides along with fission products, while in the case of U/TRU recycle only contains the losses of minor actinides from the reprocessing and recycle fuel fabrication operations. This difference in content has several implications. One impact is on the time dependent decay heat which can affect handling and the use of space in a geologic repository. Another impact concerns the HLW form and volume, since presence of minor actinides may adversely affect the ability to reduce HLW volume. The short-term radioactivity and long-term radiotoxicity of the HLW is also affected, which may be of more or less importance depending on the specific geologic disposal environment. To study these potential effects, a range of waste forms and disposal environments were used in the analysis, documenting to what extent the recycle of minor actinides in addition to plutonium may offer further benefit. Another area of investigation concerned the recycle fuel, for the fast reactor and for the thermal reactors they may support. Information to date indicates that U/Pu fuel may be simpler to fabricate and has a much more extensive database than U/TRU fuel, one of the reasons for the increased challenge for developing and deploying a U/TRU fuel cycle, and also indicates that heterogeneous recycle of the minor actinides may be even more difficult as compared to homogeneous recycle. This information was reviewed and updated to reflect the most recent studies for the purpose of informing on all aspects of the differences between U/Pu and U/TRU recycle. The results of all of these investigations will be presented to provide information on the findings concerning the value of U/TRU recycle.

Fast reactor recycle↗
DOE OSTI2017

CeLAND: search for a 4th light neutrino state with a 3 PBq 144 Ce- 144 Pr electron antineutrino generator in KamLAND

The reactor neutrino and gallium anomalies can be tested with a 3-4 PBq (75-100 kCi scale) 144 Ce- 144 Pr antineutrino beta-source deployed at the center or next to a large low-background liquid scintillator detector. The antineutrino generator will be produced by the Russian reprocessing plant PA Mayak as early as 2014, transported to Japan, and deployed in the Kamioka Liquid Scintillator Anti-Neutrino Detector (KamLAND) as early as 2015. KamLAND's 13 m diameter target volume provides a suitable environment to measure the energy and position dependence of the detected neutrino flux. A characteristic oscillation pattern would be visible for a baseline of about 10 m or less, providing a very clean signal of neutrino disappearance into a yet-unknown, sterile neutrino state. This will provide a comprehensive test of the electron dissaperance neutrino anomalies and could lead to the discovery of a 4th neutrino state for Δm$2\atop{new}$ ≳ 0.1 eV 2 and sin 2 (2θ new ) > 0.05.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2017

Spent Nuclear Fuel Canister Capacity: Have the Limits Been Reached?

The commercial US nuclear utilities have been transferring spent nuclear fuel (SNF) from spent fuel pools (SFPs) to dry storage systems since 1986. SFPs were initially constructed for temporary storage, but without SNF reprocessing options in the United States and with no final disposal pathway yet available,SFPs started to reach capacity. Hence, to allow continued operation of the nation’s commercial nuclearreactor fleet, utilities started transferring SNF from SFPs (wet storage) to dry storage. Dry storage systems have evolved from storage-only systems first loaded in 1986 to the high-capacity dual-purpose storage and transport canisters used today. A question has arisen as to whether maximum canister capacity has been reached at the current capacity of ~50 kW heat load for storage, with 37-assembly pressurized water reactor and 89-assembly boiling water reactor canisters. This paper presents a holistic overview of commercial US SNF management practices over the years, the current SFP status in terms of filled (occupied) and empty (available) locations, the expected future reactor discharges, and the decay heat load distribution of SFP inventories as of June 2013. Finally, the paper makes a case that further increase in dry storage system capacity both in terms of number of assemblies and decay heat (1) is not needed, and (2) may not be practical from the cost-benefit perspective. b

Banerjee, Kaushik↗
DOE OSTI2017

Pyroprocessing Monitoring Technology Development at Idaho National Laboratory

The Idaho National Laboratory (INL), with support from the U.S. Department of Energy, Office of Nuclear Energy, Nuclear Technology Research and Development program, has been developing advanced instrumentation and approaches for enhancing the effectiveness of nuclear material control and accounting for future reprocessing facilities with particular emphasis on pyroprocessing. Advanced modeling capabilities augment new instrumentation development, predict material flows, integrate process monitoring data, and assess overall system effectiveness of the safeguards and security system. In this paper we provide a brief overview of the Safeguards and Security by Design approach being pursued under the program and details of advanced process monitoring instrumentation under development at the INL, which includes a triple bubbler system for on-line monitoring of level and density of molten salt, sensors for monitoring actinide concentrations in molten salt, and thermal-couple instrumentation for near real time determination of Pu content in U/TRU ingots. Laboratory and field testing data will be presented, as well as integration of these sensors into a concept for utilization of process monitoring information in concert with traditional nuclear material accountancy data.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2018

Safeguards Challenges for Molten Salt Reactors

There are now a wide variety of molten salt reactor (MSR) technologies being proposed or developed that are gaining international interest and momentum toward deployment. There are two sub-categories of this class of reactors - those that are liquid fueled (i.e., the molten salt is both the fuel and the coolant) and those that have solid fuel with the molten salt used as coolant only. The liquid-fueled MSRs present unique challenges to current safeguards approaches. These challenges exist because there are currently no conceptual approaches to applying safeguards to unique, tightly coupled nuclear energy systems with the reactor core, balance of plant, and fuel cycle (everything else including salt processing and material separations) combined in a single facility. The application of safeguards to liquid-fueled MSRs will have to take into consideration several technical factors including: The homogeneous mixture of fuel, coolant, fission products, and actinides (with the attendant extremely high radiation field); Continuous variation in isotopic concentrations in the fuel salt, including removal (passive or active) of fission products, rare earth elements, and noble metals; High operating temperatures of the fuel salt; Online processing where some fraction of the inventory can be removed while the reactor is operational; Unique refueling schemes, including the ability to continuously feed the core with fresh fissile or fertile material; The presence of frozen fuel, potentially requiring a different safeguards process from the liquid fuel; and The presence of fuel outside the vessel. Additionally, If the thorium fuel cycle is employed, there will be additional complications since the resulting radiation signatures will be different from those of the uranium-based fuel cycle. The existing IAEA inspection regimes are based on the uranium-plutonium fuel cycle, item counting for nuclear reactors, and bulk material accountancy for the front and back end of the nuclear fuel cycle. These techniques and associated instrumentation for bulk accountancy have been developed predominantly for enrichment, fuel fabrication, and aqueous reprocessing. However, none of these bulk accountancy measures can be directly applied to liquid-fueled MSRs. This paper will explore some of the possible challenges in applying safeguards to molten salt reactors.

Kovacic, Donald N↗
DOE OSTI2018

Application of a Triple Bubbler Sensor for Determining the Density, Surface Tension, and Depth in Molten Salts

Electrochemical (i.e. pyroprocessing) technology is being widely studied throughout the world as a potential alternative to aqueous reprocessing of spent nuclear fuel (SNF). Central to this process is the electrorefiner (ER), in which the useful uranium in the SNF is electrochemically transported through a molten salt electrolyte to a cathode for later recovery. As part of this process, uranium, plutonium, and other actinides accumulate in the ER salt over time. Material accountancy and safeguards of these special nuclear material buildups in near real-time is a significant challenge due to the elevated processing temperatures, remote operation within a hotcell, and high radiation fields. Analytical techniques outside of the hotcell can be used to provide the SNM concentrations of salt samples from the ER. However, determining the actual mass of these materials in the ER presents a significant challenge because the density and volume within the vessel is largely unknown. The Idaho National Laboratory (INL) has developed a triple bubbler sensor capable of determining the density, surface tension, and depth of a fluid in near real-time. Previous experiments in aqueous media has shown that the sensor is capable of determining the density, surface tension and depth with accuracies on the order of 0.2%. The goal of this current work is to test the sensor in several molten salt media to calibrate and validate the triple bubbler. Experiments have been performed in LiCl-KCl eutectic salt. Calibration factors were 1.0015 and 1.26 for density and surface tension, respectively. With the above calibration factors applied, the depth of the salt in the test vessel was determined to within 0.4%. These results indicate that the triple bubbler sensor has the potential to accurately (less than 1% uncertainty) determine the density, surface, tension, and depth of the ER salt in near real-time. The triple bubbler sensor designed at INL can significantly enhance the material accountancy, safeguards, and process monitoring of the electrochemical processing of SNF.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2018

Thermodynamic Properties of Rare Earth Chlorides in Molten Salts: A Novel Approach to Experimental Electrochemistry of Molten Salts

The thermodynamic and electrochemical properties of rare earth chlorides in molten salt solutions are of interest from the standpoint of both pyrochemical processing of spent nuclear fuel and for the development of Generation IV nuclear reactors. Knowledge of key properties like activity coefficients and phase diagrams will accelerate the development of safe reliable carbon free energy. In this work, three conduits of research have been pursued and reported within the larger theme of minimization of waste in spent fuel reprocessing and associated technology development. The activity coefficient of rare earth chlorides has been investigated using ground breaking theory and experimental approach. Furthermore, an ionic size dependent activity coefficient model is presented. This book also contains research into quaternary phase diagrams for LiCl-KCl-CsCl-RECl3 molten salt systems. This book should prove an excellent introduction to anyone pursuing a career in experimental high temperature electrochemistry and molten salt chemistry.

Bagri, Prashant↗
DOE OSTI2016

IODINE ADSORPTION IN FIXED BED ADSORBER TESTS

I-129 emissions control is needed for used fuel aqueous reprocessing. I-129 capture has been studied for 40 years; Two sorbents tested in recent years – Silver Zeolite (AgZ) and silver-functionalized Aerogel (AGAero). Results show needed iodine adsorption efficiencies are possible, DFs up to10,000. Mass transfer zone (MTZ) depths ~2 in. for I2 and 8 in. for CH3I, but increase over time; deeper sorbent beds needed for efficient CH3I capture. Ag utilization between 10-70% for most test durations; lower for higher NOx. Iodine sorption capacities: ~10 g/100 AgZ and ~20 g/100 g AgAero; lower for high NOx. Nearly all adsorbed I was physisorbed iodine for I2 and CH3I.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗