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At least 1,495 records · Page 83
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Technetium, Iodine, and Chromium Adsorption/Desorption Kd Values for Vadose Zone Pore Water, ILAW Glass, and Cast Stone Leachates Contacting an IDF Sand Sequence

Performance and risk assessments of immobilized low-activity waste (ILAW) at the Integrated Disposal Facility (IDF) have shown that risks to groundwater are quite sensitive to adsorption-desorption interactions occurring in the near- and far-field environment. These interactions between the underlying sediments and the contaminants present in the leachates that descend from the buried glass, secondary waste grouts, and potentially Cast Stone low-activity waste packages have been represented in these assessments using the contaminant distribution coefficient (Kd) construct. Some contaminants (99Tc, 129I, and Cr) present in significant quantities in these wastes have low Kd values and tend to drive risk to public health and the environment. Relatively small changes in the Kd value can cause relatively large changes in the retardation factor. Thus, even relatively small uncertainty in the Kd value can result in a relatively large uncertainty in the risk determined through performance assessment modeling. The purpose of this study is to further reduce the uncertainty in Kd values for 99Tc, iodine (iodide and iodate), and Cr (chromate; CrO42-) by conducting systematic adsorption-desorption experiments using actual sand-dominated Hanford formation sediments from beneath the IDF and solutions that closely mimic Hanford vadose zone pore water and leachates from Cast Stone and ILAW glass waste forms. Twenty-four batch and 21 flow-through column experiments were conducted, yielding 261 Kd measurements for these key contaminants, and contributing to our understanding for predicting transport from wastes disposed to the IDF. While the batch Kd methodology is not well-suited for measuring Kd values for non-sorbing species (as noted by the U.S. Environmental Protection Agency), the batch Kd results presented here are not wholly inconsistent with the column Kd results, and could be used for sensitivity purposes. Results from the column experiments are consistent with the best estimate and lower range of Kd values reported by Krupka et al. and Cantrell et al.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

E-Area Low-Level Waste Facility Vadose Zone Model: Confirmation of Water Mass Balance for Subsidence Scenarios

In preparation for the next revision of the E-Area Low-Level Waste Facility (LLWF) Performance Assessment (PA), a mass balance model was developed in Microsoft Excel to confirm correct implementation of intact- and subsided-area infiltration profiles for the proposed closure cap in the PORFLOW vadose-zone model. The infiltration profiles are based on the results of Hydrologic Evaluation of Landfill Performance (HELP) model simulations for both intact and subsided cases.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Informing hazardous zones for on-board maritime hydrogen liquid and gas systems

The significantly higher buoyancy of hydrogen compared to natural gas means that hazardous zones defined in the IGF code may be inaccurate if applied to hydrogen. This could place undue burden on ship design or could lead to situations that are unknowingly unsafe. We present dispersion analyses to examine three vessel case studies: (1) abnormal external vents of full blowdown of a liquid hydrogen tank due to a failed relief device in still air and with crosswind; (2) vents due to naturally-occurring boil-off of liquid within the tank; and (3) a leak from the pipes leading into the fuel cell room. The size of the hydrogen plumes resulting from a blowdown of the tank depend greatly on the wind conditions. It was also found that for normal operations releasing a small amount of "boil- off" gas to regulate the pressure in the tank does not create flammable concentrations.

08 HYDROGEN↗
DOE OSTI2018

Identification of Residual Oil Zones in the Williston and Powder River Basins

The goal of this project by the Energy & Environmental Research Center was to systematically assess the petroleum systems of the Williston and Powder River Basins (PRB) for prospective residual oil zones (ROZs) through a geologic process modeling approach. This approach models the evolution of a sedimentary basin to predict if, when, and where reservoirs were charged with hydrocarbons. Suspected ROZs identified by this approach were evaluated for their potential oil recovery using carbon dioxide (CO 2 ) and for associated CO 2 storage. ROZs are naturally waterflooded portions of oil reservoirs with oil saturations between 25% and 40% but are at irreducible oil saturation levels with respect to water, rendering the reservoirs uneconomic using conventional recovery methods. However, using CO 2 enhanced oil recovery (EOR), substantial amounts of oil can be recovered from ROZs while simultaneously storing CO 2 . ROZs were originally identified and defined in the Permian Basin of West Texas but have since been identified or speculated in several geologic basins, including the Williston Basin and PRB.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Strategies for Lime Treatment Of D-Area Coal Storage Area (484-17D) Vadose Zone Soil

Sixty years of coal storage operations in the DCSA (484-17D, Figure 1) have resulted in vadose zone soils with a total acidity level typical of acid mine drainage soils. Field measurements from June 2018 show soil pH values ranging from 3 to 4.5 to water-table depth (10 to 12 feet). Best estimates for treatment of the acidic soils with dolomitic (agricultural) limestone suggest a required application rate ranging from 8 to 10 tons per acre per foot of soil depth to raise the soil pH from 3.5 to 5.5. The model predicts a lower bound of 3 tons per acre per foot for high-quality limestone with a particle size less than 60-mesh and an upper bound of 19 tons per acre per foot for lower-quality limestone. This compares to typical residential and agricultural lime application rates of one to four tons per acre per foot of depth.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

Dual-Zone Solar Control Indoor Shade: Demonstration at the Ronald V. Dellums Federal Building and U.S. Courthouse, 1301 Clay Street, Oakland, California and the Lawrence Berkeley National Laboratory Advanced Windows Testbed, Berkeley, California

Standard window shades are used to control sunlight, glare, window heat gains, and daylight. The challenge with conventional shades is that once the shades are lowered to reduce discomfort, daylight is reduced, which, in turn, increases the need for electric lighting. View is also obstructed, reducing the occupants’ connection to the outdoors. The strategy of subdividing the window wall and admitting daylight from above and controlling sunlight and view through the lower aperture can yield significant energy and peak demand savings over conventional shading systems, and improve the daylight quality of the indoor environment. This study evaluated a dual zone solar control (DZSC) shade with an upper, automated, horizontal, venetian blind with concave-up, matte white slats and a lower, manually operated, roller shade made of a transparent, reflective film. The automatic controls were designed to adjust the upper slat angle to maximize daylight to the room interior. The lower shade, when lowered, provided an unobstructed view to the outdoors. For the qualitative analysis, the DZSC shades were installed on windows in the southeast half of one floor in the Ronald V. Dellums Federal Building and U.S. Courthouse or hereafter referred to as the Oakland Federal Building (OFB) in Oakland, California. The position of the DZSC shades were observed and recorded periodically. Surveys were issued to occupants in the private offices and open plan workstations affected by the shades. For the quantitative analysis, the DZSC shades were installed in the south-facing windows of thermally isolated, fully instrumented, test chambers in the Advanced Windows Testbed at the Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California. Measurements of window heat loads, daylight illuminance and environmental conditions related to visual and thermal comfort were collected over a six-month, solstice-to-solstice period. The performance of the DZSC shade was compared to fabric roller shades and venetian blinds since these are the two most common types of shades used in both commercial and Federal buildings. Several DZSC design permutations were evaluated: 1) manual or automated control of the upper louver system (“man” or “auto”) and 2) tinted or silvered reflective film for the lower shade (“Gray-Gray (GG)” or “Gray-Silver (GS)”1). The automated, reflective shade (auto-GS) reduced dimmable fluorescent lighting energy use by 51% and window cooling load by 13-15% compared to a conventional fabric roller shade with dual-pane, spectrally selective, low-e windows during the summer period (winter period was not measured). Qualitative analysis revealed that the auto-GS shade was preferred by 80% of the survey respondents compared to the existing vertical fabric blinds with single-pane, tinted windows in the occupied building. Survey results indicated that visual discomfort was reduced and thermal discomfort was also reduced during warm or hot weather. Occupants expressed greater satisfaction with the unobstructed view. Installation and commissioning of the DZSC shades was fairly straightforward with some minor problems due to inadequate installation instructions and improper wiring. A few occupants expressed dissatisfaction with the automatic controls for the upper louvers due to visual discomfort, erroneous control, and motor noise.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Evaluating the performance of the immersed boundary method within the grey zone for improved weather forecasts in the HRRR model

Improved performance of the High Resolution Rapid Refresh (HRRR) weather forecast in regions of complex terrain is a primary goal of the second Wind Forecasting Improvement Project (WFIP2). The HRRR forecast uses the Weather Research and Forecasting (WRF) model at a horizontal resolution of 3 km and includes an experimental nest over the WFIP2 study area with 750 m horizontal resolution. At these resolutions the complex terrain of the WFIP2 study area, the Columbia River Gorge, is well resolved and can include steep terrain slopes. The terrain-following coordinate system used by the WRF model is susceptible to numerical instabilities as model resolution and resolved terrain slopes increase. The immersed boundary method (IBM) has been shown to reduce these instabilities at very high resolutions (roughly 10 m or less), and thus use of IBM is desirable for high resolution simulations over the WFIP2 study area. However, accuracy of the IBM appears to degrade with coarser grid resolution and the sensitivities of IBMs to grid resolution are not well understood. In this report, we work to understand the accuracy and performance of the IBM at coarser resolutions with the goal of developing an IBM for use in the grey zone, or the intermediate scales between mesoscale and large-eddy simulation. Here, several existing immersed boundary algorithms from the literature are implemented into WRF, along with a new implementation developed during this project. The IBM algorithms for the atmospheric boundary layer are evaluated within the WRF model for a range of grid resolutions. While the strong performance of IBMs at high-resolution is confirmed, important model sensitivities are also revealed. Particular focus is placed on IBM performance at intermediate grid resolutions, which to this point has not been studied in the atmospheric modeling literature.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Smart Ventilation for Advanced California Homes – Single Zone Technology Task

This study is intended to demonstrate the potential for energy savings while providing acceptable Indoor Air Quality (IAQ) for ZNE homes. It uses the concept of Smart Ventilation where ventilation systems are designed and controlled to produce the same, or better, IAQ compared to simple, continuously operated ventilation systems. The key energy saving principle for smart ventilation is that ventilation is shifted in time to when the energy required to condition the air is lower. A variety of smart ventilation controls based on outdoor temperature, occupancy and auxiliary fan sensing were developed and assessed across homes built to the 2016 Title 24 Prescriptive standards in California climate regions. Simulations used a co-simulation strategy that combines EnergyPlus with CONTAM. The IAQ calculations were based on the equivalent ventilation principle outlined in the ASHRAE 62.2-2016 ventilation standard, Appendix C. Two prototype homes were simulated (1-story 2,100 ft2 and 2-story 2,700 ft2). Their envelope airtightness was varied between 1, 3 and 5 ACH50. Climate zones were chosen to reflect the variety of heating and cooling demand throughout California. A weighted average analysis was used to generalize the energy predictions across the projected new housing stock in the state. Temperature-based controls were found to be effective, with the most successful smart controls reducing weighted average site ventilation energy use by about 40%, while TDV weighted average ventilation energy reductions were higher, up to roughly 60%. Results were also normalized to ensure identical IAQ in all cases, and the weighted average site and TDV ventilation savings increased, up to 55% and 72% ventilation savings, respectively, for the top-performing temperature-based controls. Peak demand during the 2-6pm period on the hottest days of the year was reduced by up to 400 watts. More than 90% of site energy savings were for heating end-uses, while TDV energy savings were split fairly evenly between heating and cooling. On average, the smart controls reduced occupant pollutant exposure by 0-10%, and they increased ventilation rates by roughly 20%. Occupancy-based controls that accounted for contaminants released by building materials and furnishings during unoccupied times were generally ineffective, with very low energy savings. Performance was improved somewhat through use of a 1-hour pre-occupancy flush out period, though savings were still marginal compared to temperature-based controls. All temperature and occupancy controls were also tested with auxiliary fan sensing capability (i.e., accounting for the use of other exhaust devices in the home, like bathroom or kitchen fans). Auxiliary fan sensing increased energy savings in all cases, from roughly 5 to 15%.

42 ENGINEERING↗
DOE OSTI2019

Novel Zoned Waste-forms for High-Priority Radionuclide Waste Streams

This report describes the potential of a novel class of materials—α-ZrW 2 O 8 , Zr 2 WP 2 O 12 , and related compounds that contract upon amorphization as possible radionuclide waste-forms. The proposed ceramic waste-forms would consist of zoned grains, or sintered ceramics with center- loaded radionuclides and barren shells. Radiation-induced amorphization would result in core shrinkage but would not fracture the shells or overgrowths, maintaining isolation of the radionuclide. In this report, we have described synthesis techniques to produce phase-pure forms of the materials, and how to fully densify those materials. Structural models for the materials were developed and validated using DFPT approaches, and radionuclide substitution was evaluated; U(IV), Pu(IV), Tc(IV) and Tc(VII) all readily substitute into the material structures. MD modeling indicated that strain associated with radiation-induced amorphization would not affect the integrity of surrounding crystalline materials, and these results were validated via ion beam experimental studies. Finally, we have evaluated the leach rates of the barren materials, as determined by batch and flow-through reactor experiments. ZrW 2 O 8 leaches rapidly, releasing tungstate while Zr is retained as a solid oxide or hydroxide. Tungsten release rates remain elevated over time and are highly sensitive to contact times, suggesting that this material will not be an effective waste-form. Conversely, tungsten releases rates from Zr 2 WP 2 O 12 rapidly drop, show little dependence on short-term changes in fluid contact time, and in over time, become tied to P release rates. The results presented here suggest that this material may be a viable waste-form for some hard-to-handle radionuclides such as Pu and Tc.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Geomechanical Simulation of Big Hill Strategic Petroleum Reserve - Calibration of Model Containing Shear Zone

A finite element numerical analysis model, that consists of a realistic mesh capturing the geometries of Big Hill (BH) Strategic Petroleum Reserve (SPR) site using the multi-mechanism deformation (MD) salt constitutive model and including data taken daily of the wellhead pressure and level of the oil-brine interface, has been upgraded. The upgraded model contains the shear zone to examine the interbed behavior in a realistic manner. The salt creep rate is not uniform in the salt dome, and creep test data for BH salt is limited. Therefore, a model calibration is necessary to simulate the geomechanical behavior of the salt dome. Cavern volumetric closures of SPR caverns calculated from sonar survey reports are used for the field baseline measurement. The structure factor, A 2 , and transient strain limit factor, K 0 , in the M-D constitutive model are used for model calibration. An A 2 value obtained experimentally from the BH salt and K 0 value of WIPP salt are used as the baseline values. To adjust the magnitude of A 2 and K 0 , multiplication factors A 2 F and K 0 F are defined, respectively. The A 2 F and K 0 F values of the salt dome and salt drawdown layer of elements surrounding each SPR cavern have been determined through a number of back fitting analyses. The trendlines of the predictions and sonar data match up well for BH 101, 103, 104, 106, 110, 111, 112, and 113. The prediction curves are close to the sonar data for BH 102 and 114. However, the prediction curves for BH 105, 107, 108, and 109 are not close to the sonar data. An inconsistency was found in the sonar data, i.e. the volume measured later is larger than that before in some time intervals, even if the leached volume is taken into account, for BH 101, 104, 106, 107, and 112. Project discussions are needed to determine possibilities on how to resolve the issues and determine the best path forward for future computer modeling attempts.

02 PETROLEUM↗
DOE OSTI2020

Comoparison of Slit Trench and Engineered Trench 3D Vadose Zone Conceptual Models

In the next revision of the E-Area Low-Level Waste Facility (ELLWF) Performance Assessment (PA), radionuclide groundwater transport from slit (ST) and engineered trenches (ET) will be simulated using 3-dimensional PORFLOW models representing the vadose zone. In total, the conceptual framework will aim to model 29 total trenches with a degree of conservatism that provides a high level of confidence in meeting performance objectives. The implementation of generic conceptual models allows for a reasonable number of simulation scenarios, thereby reducing the chances of errors and enabling a better one-to-one comparison between the results, while still capturing the most important features of each trench. The current investigation seeks to understand if a generic trench model based on the general ET footprint can justifiably be used for representing both STs and ETs while maintaining a reasonable degree of conservatism. In this process, the groundwater transport of several key radionuclides was simulated for both ET and ST geometries and the flux-to-the-water-table profiles were compared. For all radionuclides simulated, the ET geometry is shown to be conservative (i.e., produces the highest peak flux to the water table).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

An Eight-County Appraisal of the San Andres Residual Oil Zone (ROZ) 'Fairway' of the Permian Basin

This document assesses the size and distribution of the oil resource in an eight-county portion of the San Andres residual oil zone (ROZ) fairway in the Permian Basin. Using well log analysis, the study divided the ROZ into partitions, developed a database of geologic properties for each partition and estimated the oil in place in each partition. The study then used the FE/NETL CO 2 Prophet Model to estimate the oil that could be produced and CO 2 stored from applying CO 2 EOR to each partition. With the FE/NETL Onshore CO 2 EOR Cost Model, the commercially viable partitions were identified as those that could produce oil and store CO 2 economically at an oil price of $75/STB. The remaining geologically viable partitions could use CO 2 EOR to store CO 2 with production of oil to offset some of the costs. The database used for this study, and a report describing the database is available on NETL's website under the Collection Name Eight-County San Andres ROZ Appraisal.

02 PETROLEUM↗
DOE OSTI2020

Eight County Permian Basin Residual Oil Zone (ROZ) Database

This document describes the spreadsheet geologic database named ROZ_SanAnd_8.xlsm used in the report, ''An Eight-County Appraisal of the San Andres Residual Oil Zone (ROZ) 'Fairway' of the Permian Basin''. The dataset provides geologic properties for ROZ partitions in San Andres formation in eight counties in the Permian Basin. The geologic data is used to estimate total oil in place in each partition and provides the inputs needed to estimate the oil that can be produced and CO 2 stored from the application of CO 2 EOR to a partition. The database and the appraisal report are available on NETL's website under the Collection Name: Eight-County San Andres ROZ Appraisal.

02 PETROLEUM↗
DOE OSTI2020

A Four-County Appraisal of the San Andres Residual Oil Zone (ROZ) 'Fairway' of the Permian Basin

This document assesses the size and distribution of the oil resource in a four-county portion of the San Andres residual oil zone (ROZ) fairway in the Permian Basin. Using well log analysis, the study divided the ROZ into partitions, developed a database of geologic properties for each partition and estimated the oil in place in each partition. The study then used the FE/NETL CO 2 Prophet Model to estimate the oil that could be produced and CO 2 stored from applying CO 2 EOR to each partition. With the FE/NETL Onshore CO 2 EOR Cost Model, the commercially viable partitions were identified as those that could produce oil and store CO 2 economically at an oil price of $75/STB. The remaining geologically viable partitions could use CO 2 EOR to store CO 2 with production of oil to offset some of the costs. The database used for this study, and a report describing the database is available on NETL's website under the Collection Name: Four-County San Andres ROZ Appraisal.

02 PETROLEUM↗
DOE OSTI2020

Four County Permian Basin San Andres Residual Oil Zone (ROZ) Database

This document describes the spreadsheet geologic database named ROZ_SanAnd_4.xlsm used in the report ''A Four-County Appraisal of the San Andres Residual Oil Zone (ROZ) 'Fairway' of the Permian Basin''. The dataset provides geologic properties for ROZ partitions in San Andres formation in four counties in the Permian Basin. The geologic data is used to estimate total oil in place in each partition and provides the inputs needed to estimate the oil that can be produced and CO 2 stored from the application of CO 2 EOR to a partition. The database and the appraisal report are available on NETL's website under the Collection Name: Four-County San Andres ROZ Appraisal.

02 PETROLEUM↗
DOE OSTI2020

Vadose Zone Flow and Transport Parameters Data Package for the Hanford Site Composite Analysis and Cumulative Impact Evaluation

This report provides a description of the basis for the development and implementation of a conceptual model for vadose zone flow and transport for the composite analysis (CA) groundwater pathway analysis and the cumulative impact evaluation (CIE). The parameterization for a numerical model is intimately linked to the conceptual model framework. The report describes the basis for the selection of hydraulic and transport parameters for the hydrostratigraphic units (HSUs) identified in the 200 East and 200 West Areas. Whenever data are sparse or unavailable, surrogate hydraulic properties are chosen based on samples collected within the 200 Areas and nearby locations that are representative of sediments characteristic of the HSUs identified elsewhere.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Vadose Zone Model for A Trenches Area for Composite Analysis

The objectives of the vadose modeling for the updated Hanford Site composite analysis (CA) are to simulate the flow and transport of water and radionuclide releases from the surface to the water table and to provide radionuclide transfer rates for the plateau to river (P2R) model, version 8.3. Water additions include natural recharge and water discharged to the ground as a result of industrial processes associated with Hanford Site operations. Contaminant sources include radionuclides in water discharged to the ground during operations and radionuclides disposed “dry” in solid waste burial grounds or other means. The parallel version of the Subsurface Transport Over Multiple Phases (STOMP) simulator, officially named the exascale Subsurface Transport Over Multiple Phases (eSTOMP), is used to simulate flow and transport for the vadose models. The scope of this ECF is to document the development and results of the A Trenches Area vadose zone model. The A Trenches Area model covers the region between the 200 East Area and southwest of the 216-B-3 Pond. The primary waste sites in this area are cribs associated with PUREX Plant (202-A).

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