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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 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Development of a Self-Consistent Model of Plutonium Sorption: Quantification of Sorption Enthalpy and Ligand-Promoted Dissolution

This university lead SBR project is a collaboration lead by Dr. Brian Powell (Clemson University) with co-principal investigators Dan Kaplan (Savannah River National Laboratory), Yuji Arai (presently at the University of Illinois), Udo Becker (U of Michigan) and Rod Ewing (presently at Stanford University). Hypothesis: The underlying hypothesis of this work is that strong interactions of plutonium with mineral surfaces are due to formation of inner sphere complexes with a limited number of high-energy surface sites, which results in sorption hysteresis where Pu(IV) is the predominant sorbed oxidation state. The energetic favorability of the Pu(IV) surface complex is strongly influenced by positive sorption entropies, which are mechanistically driven by displacement of solvating water molecules from the actinide and mineral surface during sorption. Objectives: The overarching objective of this work is to examine Pu(IV) and Pu(V) sorption to pure metal (oxyhydr)oxide minerals and sediments using variable temperature batch sorption, X-ray absorption spectroscopy, electron microscopy, and quantum-mechanical and empirical-potential calculations. The data will be compiled into a self-consistent surface complexation model. The novelty of this effort lies largely in the manner the information from these measurements and calculations will be combined into a model that will be used to evaluate the thermodynamics of plutonium sorption reactions as well as predict sorption of plutonium to sediments from DOE sites using a component additivity approach.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2018

Chemical Composition Analysis and Product Consistency Tests of the ORP Phase 5 Nepheline Study Glasses

In this report, the Savannah River National Laboratory (SRNL) provides chemical analyses and Product Consistency Test (PCT) results for a series of simulated high-level waste glass compositions fabricated by the Pacific Northwest National Laboratory (PNNL). These data will be used in the development of improved models for the prediction of nepheline crystallization in support of the Hanford Tank Waste Treatment and Immobilization Plant (WTP).

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DOE OSTI2019

Chemical Composition Analysis and Product Consistency Tests of the ORP Phase 6 Nepheline Study Glasses

In this report, Savannah River National Laboratory (SRNL) provides chemical analyses and Product Consistency Test (PCT) results for a series of simulated high-level waste (HLW) glass compositions fabricated at Pacific Northwest National Laboratory (PNNL). The results of this effort will improve the ability to predict the impacts of glass composition and nepheline crystallization on the durability of HLW glasses. Chemical analyses were performed on a representative sample of each of the quenched glasses to allow for comparisons with the targeted compositions. A review of the individual glass composition measurements identified no analytical issues of concern. Minor differences between the targeted and measured concentrations of some of the baseline glass components were noted, including some high values for Fe 2 O 3 , and some low values for Al 2 O 3 , Li 2 O, Na 2 O and P 2 O 5 . The PCT Method-A was performed in triplicate on each of the quenched and canister centerline cooled (CCC) versions of the glasses to assess chemical durability. A review of the leachate analyses and standard solution data identified no issues with the analytical methods. Some of the CCC versions of the study glasses have normalized concentration for boron (NC B ) values that are higher than the Environmental Assessment glass benchmark NC B value of 16.695 g/L. For some of the study glasses, the NC B values were higher after the CCC heat treatment. The normalized concentrations for lithium and sodium (NC Li and NC Na ) followed this same trend. For many of these glasses, the changes in the normalized concentration for silicon (NC Si ) values were not congruent with the changes in NC B , NC Li , and NC Na values. It may be valuable for PNNL to perform a more complete review of the influence of composition and heat treatment on the PCT responses of the glasses described in this report to draw further conclusions, including any potential correlations with the methods used in selecting these glass compositions for study.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Product Consistency Test Leachate Data for Nepheline Scoping Study Glasses

In this report, the Savannah River National Laboratory provides chemical analysis for a series of leachates resulting from Product Consistency Tests of nepheline study glasses performed at the Pacific Northwest National Laboratory. A review of the standard solution data identified no issues with the analytical methods. The results of this scoping study will be used as part of an effort to better understand nepheline crystallization in high-level nuclear waste glasses with high concentrations of aluminum and sodium.

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DOE OSTI2019

Self-Consistent Optics with Strong Space Charge

A method for finding self-consistent beam optics in the presence of strong space charge defocusing effect is developed which is based on the eigenvectors of the transfer matrix. It allowed us to obtain solutions for the Σ-matrix in the case of the space charge tune depression as high as 25%. These solutions were used to build a matched initial distribution of particles for tracking simulations with the Synergia code. The results of simulations are presented and discussed.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

A Themodynamically Consistent Fractional Visco-Elasto-Plastic Model with Memory-Dependent Damage for Anomalous Materials

We develop a thermodynamically consistent, fractional visco-elastoplastic model coupled with damage for anomalous materials. The model utilizes Scott-Blair rheological elements for both visco- elastic/plastic parts. The constitutive equations are obtained through Helmholtz free-energy potentials for Scott-Blair elements, together with a memory-dependent fractional yield function and dissipation inequalities. A memory-dependent Lemaitre-type damage is introduced through fractional damage energy release rates. For time-fractional integration of the resulting nonlinear system of equations, we develop a first-order semi-implicit fractional return-mapping algorithm. We also develop a finite-difference discretization for the fractional damage energy release rate, which results into Hankel-type matrix-vector operations for each time-step, allowing us to reduce the computational complexity from O(N 3 ) to O(N 2 ) through the use of Fast Fourier Transforms. Our numerical results demonstrate that the fractional orders for visco-elasto-plasticity play a crucial role in damage evolution, due to the competition between the anomalous plastic slip and bulk damage energy release rates.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Product Consistency Test Results for the High-Chromium Matrix Glasses

This report provides chemical analysis of a series of Product Consistency Test (PCT) leachates from simulated nuclear waste glasses. The resulting data will be used in the development of improved property/composition models. For some of the glass leachates, minor scatter among the triplicate values of some analytes was observed. For other leachates, there were more significant differences among the triplicate values. A review of the PCT data noted that there was little difference between the normalized values on the basis of targeted or measured glass composition. Several of the study glasses, both quenched and canister centerline cooled, have NC i values that are greater than the Hanford Tank Waste Treatment and Immobilization Plant immobilized low-activity waste constraint of 4 g/L for B, Na, and Si. For many of the study glasses, heat treatment had only a marginal impact on the NC i values. The samples of the Environmental Assessment (EA) reference glass included with each PCT set had inconsistent NC i values, although some degree of variation in NC i values for the EA glass is typical. The release rates for boron and sodium were highly correlated for the study glasses, while for the other analytes, less correlation was observed.

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DOE OSTI2019

X-Ray Diffraction and Product Consistency Test Results for the Phase 6 Study of Nepheline Formation in High-Level Waste Glasses

Hanford high-level waste (HLW) contains relatively high concentrations of Al 2 O 3 . A major constraint limiting the waste loading of high-Al 2 O 3 glasses is nepheline (nominally NaAlSiO 4 ) formation upon slow cooling of HLW glasses after melts are poured into steel canisters. The model currently planned to be used at the Hanford Waste Treatment and Immobilization Plant (WTP) for avoiding nepheline formation is too conservative and drastically limits waste loading. To increase operational flexibility and effectively operate the WTP, the effects of glass composition on glass properties must be determined and glass property-composition models must be developed. Determining the impacts of glass composition on nepheline formation and the effects of nepheline on Product Consistency Test (PCT) response is an important part of this effort. As a part of this effort, data related to the Hanford high-Al 2 O 3 HLW composition region was generated to supplement existing data for model development. Twenty glasses were fabricated, heat treated, and analyzed for crystallinity and PCT response. The heat treatment was designed to mimic the canister centerline cooling (CCC) profile of Hanford HLW glass canisters. It was found that only 6 of the 20 prepared glasses (#4, #7, #8, #10, #19, and #20) formed nepheline upon heat treatment. All glasses except for one (#19) precipitated spinel upon quenching and no glasses contained nepheline upon quenching. Of the 20 glasses, the PCT-normalized boron release of the quenched glasses and all but five of the CCC glasses satisfied the environmental assessment glass benchmark value (16.695 g/L). The CCC glass samples that exceeded the limit were #8 (48.21 g/L), #10 (19.77 g/L), #13 (20.17 g/L), #19 (60.85 g/L), and #20 (61.08 g/L). Those glasses coincide with the highest amounts of nepheline found in the CCC glasses, except for #13, which did not form nepheline after CCC.

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DOE OSTI2020

The Precision of Product Consistency Tests with Environmental Assessment Glass

Several series of triplicate tests conducting following the ASTM C1285 product consistency test method have been performed using samples of Environmental Assessment glass in Teflon™ and steel test vessels. The results of tests with test parameters within the ranges specified in the PCT method A procedure were used to calculate repeatability and reproducibility precision statistics for tests in each type of vessel. These show the test response and test precision attained in tests conducted in Teflon™ and stainless steel test vessels are statistically indistinguishable.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Assessing the Consistency of Estimated Ground Cover Fractions between the BLM AIM Method and Optical Remote Sensing Method

Since 2012, Argonne National Laboratory (Argonne) has supported the Bureau of Land Management (BLM) in developing remote sensing methodologies for long-term environmental monitoring of Palo Verde Mesa in eastern Riverside County, California, including methods for: detailed mapping of ephemeral streams, estimating fractional cover of desert-land surface components (e.g., trees, shrubs, litters, and bare ground), evaluating erosion risk or land stability, and characterizing vegetation alliances using spatial structure and geostatistical approaches. These studies showed the promise of remote sensing for monitoring changes in desert landscapes by providing information that would be difficult to obtain through field surveys. During this time the BLM has also worked to establish long-term monitoring protocols and compiled field-observation data collected using standardized protocols from the Assessment, Inventory, and Monitoring (AIM) strategy. The AIM data can be compared to data derived from remote sensing methods to evaluate their relative operational utility in monitoring landscape change. If ground cover estimated using remotely sensed imagery is comparable to AIM ground cover estimates, then remote sensing can be used to monitor whether any land cover change in desert landscapes may be related to solar energy development. Therefore, the goal of this study was to determine the consistency in ground cover estimates between AIM data and those derived from publicly- available remotely sensed imagery, such as that available through the U.S. Department of Agriculture, National Agricultural Imagery Program (NAIP), to examine feasibility of a remote sensing method for complementing AIM monitoring. Based on the image analysis in this study, we also provide recommendations for how small unmanned aerial system (sUAS) data may be used to complement BLM’s AIM data and NAIP imagery for future vegetation monitoring. The ground cover types we originally planned to investigate were trees, shrubs, and bare ground. However, the small sample size and a limited range of cover fraction of trees and shrubs in the AIM dataset (e.g., 33 samples with a maximum shrub cover of 18%, 14 samples with a maximum tree cover of 17%) did not allow for performing a meaningful evaluation for the remote sensing approach. Therefore, we conducted the study focusing on bare ground, foliar, and rock cover, all of which are indicators reported in the AIM remote sensing dataset.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

Product Consistency Test Results for the HFG1 Glasses

The U.S. Department of Energy (DOE) is responsible for building the Hanford Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford site in Washington to remediate 55 million gallons of radioactive waste that is temporarily stored in 177 underground tanks. The Office of River Protection (ORP) has requested that the Savannah River National Laboratory (SRNL) contribute in areas of recognized capabilities and expertise for glass waste form development to support successful startup of the WTP. As part of this effort, the Pacific Northwest National Laboratory (PNNL) is developing, batching, and fabricating simulated high-level waste (HLW) glasses to generate the associated property data needed to validate or identify areas of potential characterization improvement in the current glass property/composition models. Currently, the models cover only a small fraction of the waste compositions projected in the Hanford tank farm; therefore, the models must be expanded to include high fluoride compositions to successfully complete the WTP mission. SRNL support of this work is defined in the Task Technical and Quality Assurance Plan (TTQAP). This report provides the results of the Product Consistency Test (PCT) leachates from the High Fluoride Glasses-1 (HFG1), a series of simulated nuclear waste glasses fabricated at PNNL. The series included quenched (Q) and canister-centerline cooled (CCC) versions of the glasses. The glasses were selected as part of a broader study of the influence of glass composition on chemical durability, sulfur retention, and other properties. These data will be used to validate or identify areas of potential characterization improvements in the current glass property/composition models.

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DOE OSTI2019

The Precision of Product Consistency Tests with Reference Glasses ARM-1 and SRM 623

An interlaboratory study (ILS) was conducted in 2014 to measure the precision with which the ASTM-International product consistency test method A (PCT-A) can be performed using properly prepared samples of reference glass ARM-1 or SRM 623 and test parameter values near the centers of ranges specified in procedure ASTM C1285. The ILS did not evaluate the full range of test parameter values allowed in the PCT-A method and the results do not represent the precision that should be expected if extreme values of the ranges are used. However, the precision measured in the ILS quantified the precision of tests conducted with mean parameters that were used to estimate the effects of individual parameters. Follow-on tests were conducted to assess the effects of several individual test parameter values on the test response and uncertainties in the derived glass dissolution rates. The effects of particle size distributions in glass samples prepared by wet- and dry-sieving methods, methods to remove fines, and the limiting parameter values for the water-to-glass (w/g) mass ratio and test duration allowed in PCT-A were measured. Test responses for all variations except test duration exceeded the precision measured in the ILS for conducting triplicate PCT-A tests within a single laboratory. The accuracy of glass dissolution rates derived from PCT results benefits from using a tighter control of these test variables than required in ASTM C1285. Comparison with previous analyses of the method shows how use of the relative standard deviation to represent the test precision can be misleading, and that the mean response and standard deviation should both be considered.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Product Consistency Test Results for the LAW ALG Glasses

This report provides the results of the Product Consistency Test leachates from the Low-Activity Waste Algorithm glasses, a series of simulated nuclear waste glasses designed and fabricated at the Pacific Northwest National Laboratory. The series included quenched and canister centerline cooled versions of the glasses. These data will be used in the development, validation, and implementation of enhanced property/composition models for waste glass vitrification at Hanford.

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DOE OSTI2022

Composition Measurements and Product Consistency Test Results for the EMHQ-LBE-04-B Glass

This report provides the results from the chemical analyses of the glass composition and the Product Consistency Test leachate analyses for the EMHQ-LBE-04-B glass. These data will be used in the development, validation, and implementation of enhanced property/composition models for waste glass vitrification at Hanford.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Improving Predictive Capability in REHEDS Simulations with Fast, Accurate, and Consistent Non-Equilibrium Material Properties

Predictive design of REHEDS experiments with radiation-hydrodynamic simulations requires knowledge of material properties (e.g. equations of state (EOS), transport coefficients, and radiation physics). Interpreting experimental results requires accurate models of diagnostic observables (e.g. detailed emission, absorption, and scattering spectra). In conditions of Local Thermodynamic Equilibrium (LTE), these material properties and observables can be pre-computed with relatively high accuracy and subsequently tabulated on simple temperature-density grids for fast look-up by simulations. When radiation and electron temperatures fall out of equilibrium, however, non-LTE effects can profoundly change material properties and diagnostic signatures. Accurately and efficiently incorporating these non-LTE effects has been a longstanding challenge for simulations. At present, most simulations include non-LTE effects by invoking highly simplified inline models. These inline non-LTE models are both much slower than table look-up and significantly less accurate than the detailed models used to populate LTE tables and diagnose experimental data through post-processing or inversion. Because inline non-LTE models are slow, designers avoid them whenever possible, which leads to known inaccuracies from using tabular LTE. Because inline models are simple, they are inconsistent with tabular data from detailed models, leading to ill-known inaccuracies, and they cannot generate detailed synthetic diagnostics suitable for direct comparisons with experimental data. This project addresses the challenge of generating and utilizing efficient, accurate, and consistent non-equilibrium material data along three complementary but relatively independent research lines. First, we have developed a relatively fast and accurate non-LTE average-atom model based on density functional theory (DFT) that provides a complete set of EOS, transport, and radiative data, and have rigorously tested it against more sophisticated first-principles multi-atom DFT models, including time-dependent DFT. Next, we have developed a tabular scheme and interpolation methods that compactly capture non-LTE effects for use in simulations and have implemented these tables in the GORGON magneto-hydrodynamic (MHD) code. Finally, we have developed post-processing tools that use detailed tabulated non-LTE data to directly predict experimental observables from simulation output.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Product Consistency Test Results for the LAW HPVR Glasses

This report summarizes the chemical analysis of Product Consistency Test (PCT) leachates received from Pacific Northwest National Laboratory (PNNL). The leachates are from a series of simulated nuclear waste glasses designated Low-Activity Waste High PCT and VHT Response (LAW HPVR) glasses that were designed and fabricated at PNNL. The glasses included both quenched and canister centerline cooled glasses. The reported data will be used in the development, validation, and implementation of enhanced property/composition models for waste glass vitrification at Hanford. The elemental release for the study glasses is reported as normalized concentration (NC i ). NC i of several elements was computed for both the target and measured glass compositions, which were similar, resulting in no significant differences when computing the NC i values. The majority of the glasses exhibited NC B , NC Na , and NC Si values that were greater than the Hanford Tank Waste Treatment Plant (WTP) low-activity waste constraint of 4 g/L. Several blank solutions included with the study glasses had K, Na, and Si concentrations above the analytical detection limit. Additionally, several of the reference glasses that were included with the study glasses had Na concentrations that were higher than expected. The unexpected analyte concentrations in the reference glass and blank solutions were insignificant with respect to the reported NC i values, and are noted for completeness and their experimental relevance.

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DOE OSTI2023

Product Consistency Test Results for the LAW ML1 Glasses

This report summarizes the chemical analysis of Product Consistency Test (PCT) leachates received from Pacific Northwest National Laboratory (PNNL). The leachates are from a series of quenched simulated nuclear waste glasses designated Low-Activity Waste Machine Learning (LAW ML1) glasses that were designed and fabricated at PNNL. The reported data will be used in the development, validation, and implementation of enhanced property/composition models for waste glass vitrification at Hanford. The elemental release for the study glasses is reported as normalized concentration NCi. NCi of several elements was computed for both the target and measured glass compositions, which were similar, resulting in no significant differences. Several of the glasses exhibited NC B , NC Na , and/or NC Si values that were greater than the Waste Treatment Plant (WTP) low-activity waste constraint of 4 g/L. All reference glasses included with the study glasses had measurements that fell within the expected ranges.

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