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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 1,639 records · Page 91
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Post-Closure Monitoring Report for Corrective Action Unit 98, Frenchman Flat, Underground Test Area, Nevada National Security Site, Nevada for Calendar Year 2016 (January 2016–December 2016), Revision 0

Corrective Action Unit (CAU) 98: Frenchman Flat on the Nevada National Security Site was the location of 10 underground nuclear tests. CAU 98 underwent a series of investigations and actions in accordance with the Federal Facility Agreement and Consent Order to assess contamination of groundwater by radionuclides from the tests. A Closure Report completed that process in 2016 and called for long-term monitoring, use restrictions (URs), and institutional controls to protect the public and environment from potential exposure to contaminated groundwater. Three types of monitoring are performed for CAU 98: water quality, water level, and institutional control. These are evaluated to determine whether the UR boundaries remain protective of human health and the environment, and to ensure that the regulatory boundary objectives are being met. Additionally, monitoring data are used to evaluate consistency with the groundwater flow and contaminant transport models because the contaminant boundaries (CBs) calculated with the models are the primary basis of the UR boundaries. In summary, the monitoring results from 2016 indicate the regulatory controls on the closure of CAU 98 remain effective in protection of human health and the environment. Recommendations resulting from this first year of monitoring activities include formally incorporating wells UE-5 PW-1, UE-5 PW-2, and UE-5 PW-3 into the groundwater-level monitoring network given their strategic location in the basin; and early development of a basis for trigger levels for the groundwater-level monitoring given the observed trends. Additionally, it is recommended to improve the Real Estate/Operations Permit process for capturing information important for evaluating the impact of activities on groundwater resources, and to shift the reporting requirement for this annual report from the second quarter of the federal fiscal year (end of March) to the second quarter of the calendar year (end of June).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Post-Closure Monitoring Report for Corrective Action Unit 98, Frenchman Flat, Underground Test Area, Nevada National Security Site, Nevada for Calendar Year 2016 (January 2016–December 2016), Revision 1

Corrective Action Unit (CAU) 98: Frenchman Flat on the Nevada National Security Site was the location of 10 underground nuclear tests. CAU 98 underwent a series of investigations and actions in accordance with the Federal Facility Agreement and Consent Order to assess contamination of groundwater by radionuclides from the tests. A Closure Report completed that process in 2016 and called for long-term monitoring, use restrictions (URs), and institutional controls to protect the public and environment from potential exposure to contaminated groundwater. Three types of monitoring are performed for CAU 98: water quality, water level, and institutional control. These are monitored to determine whether the UR boundaries remain protective of human health and the environment, and to ensure that the regulatory boundary objectives are being met. Monitoring data will be used in the future, once multiple years of data are available, to evaluate consistency with the groundwater flow and contaminant transport models because the contaminant boundaries calculated with the models are the primary basis of the UR boundaries. Six wells were sampled for water-quality monitoring in 2016. Contaminants of concern were detected only in the two source/plume wells already known to contain contamination as a result of a radionuclide migration experiment. The tritium concentration in both wells is slowly decreasing. The water-level monitoring network includes 16 wells. Depth to water measured in 2016 in all wells is consistent with recent measurements. Institutional control monitoring confirmed the URs are recorded in U.S. Department of Energy and U.S. Air Force land management systems, and that no activities within Frenchman Flat basin are occurring that could potentially affect the contaminant boundaries. Survey of groundwater resources in basins surrounding Frenchman Flat similarly identify no current or pending development that would indicate the need to increase monitoring activities or would otherwise cause concern for the closure decision. The URs continue to prevent exposure of the public, workers, and the environment to contaminants of concern by preventing use of potentially contaminated groundwater.

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

Life-cycle Analysis of Conversion of Post-Use Plastic via Pyrolysis with the GREET Model

In this report, we present an updated LCA of the PTF pathway developed at Argonne. Benavides et al. (2017) analyzed the environmental impact of producing ultra-low sulfur (ULS) diesel fuel from PUP via pyrolysis (the most common PTF technology). We used the Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET®) model and collected data from eight PTF companies to assess the potential energy and environmental benefits associated with this technology (Argonne, 2020). We conducted a survey and aggregated the dataset based on the different responses, which included plant capacity, process yields, feedstock composition, material and energy inputs, and outputs, and other parameters. We calculated the energy, greenhouse gas (GHG) emissions, and water consumption of its intermediate product pyrolysis oil and final product PUP-derived ULS diesel and compared the results to those metrics for their conventional counterparts (crude naphtha and petroleum ULS diesel fuel).

10 SYNTHETIC FUELS↗
DOE OSTI2025

Non-Resource Conservation and Recovery Act Corrective Action Unit (CAU) Post-Closure Inspection Report, Nevada National Security Site, Nevada For Calendar Year 2024

This report includes visual inspection results, descriptions of maintenance and repair activities, and recommendations for calendar year 2024 for use restrictions at corrective action sites located on the Nevada National Security Site (NNSS) and on the Nevada Test and Training Range that are accessed through the NNSS Main Gate.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2019

The Interaction Between Boundary Layer and Convection Schemes in a WRF Simulation of Post‐Cold‐Frontal Clouds over the ARM East North Atlantic Site

The correct representation of lowlevel midlatitude clouds found in the wake of cold fronts strongly relies on the representation of planetary boundary layer (PBL) and convection processes, which are typically parameterized separately in numerical models. Using the Weather Research and Forecasting Model (WRF), this study investigates how distinct pairs of PBL and convection parameterization schemes represent cloud fraction in the postcoldfrontal region. The simulations focus on the region of the DOEARM Eastern North Atlantic observation site in the Azores Islands in the wake of a cold front that passed on December 25, 2015. Different PBL and convection schemes are combined to create 12 distinct configurations. The main differences between the selected physical parameterizations are the strength of vertical mixing and the entrainment. The simulations produce a wide range of cloud fractions, where some configurations significantly underestimate while others clearly overestimate satellite and surfacebased estimates of cloud fraction. A skill score is used to quantitatively assess the performance of each configuration with respect to groundbased radar data. The key processes that are found to significantly impact the cloud fraction distribution are the strength of the PBL decoupling, the vertical wind shear, entrainment and detrainment rates in shallow convection and the occurrence of drizzle. This indicates that to successfully simulate postcoldfrontal clouds, modeled physics must balance strong internal vertical mixing and weak exchange with the free troposphere. For this case study, cloud fraction was more sensitive to the choice of convection scheme than PBL scheme.

moist convection interaction between parameterizat↗
NASA NTRSDate not supplied

Entry Guidance Design and Post-Flight Performance of the Mars 2020 Mission

Like its predecessor Mars Science Laboratory, the Mars 2020 mission successfully utilized a derivative of the Apollo Entry Terminal Point Controller guidance algorithm, whereby bank angle controls range flown along a trajectory. The flight performance of this algorithm in conjunction with a range-trigger for parachute deploy delivered the Perseverance rover to 1.7 km from the expected touchdown location within an ellipse of 7.5 x 5.2 km. This miss distance is largely attributed to atmospheric and aerodynamic modeling uncertainties between the design and as-flown trajectory. This algorithm for guided entry continues to provide a solid basis for Mars missions to improve upon.

Guidance↗
NASA NTRSDate not supplied

Post-Flight EDL Entry Guidance for the Mars 2020 Mission

Like its predecessor Mars Science Laboratory, the Mars 2020 mission successfully utilized a derivative of the Apollo Entry Terminal Point Controller guidance algorithm, whereby bank angle controls range flown along a trajectory. The flight performance of this algorithm in conjunction with a range-trigger for parachute deploy delivered the Perseverance rover to 1.7 km from the expected touchdown location within an ellipse of 7.5 x 5.2 km. This miss distance is largely attributed to atmospheric and aerodynamic modeling uncertainties between the design and as-flown trajectory. This algorithm for guided entry continues to provide a solid basis for Mars missions to improve upon.

Guidance↗
DOE OSTI2015

Post-Irradiation Examination of 237Np Targets for 238Pu Production

Oak Ridge National Laboratory is recovering the US 238 Pu production capability and the first step in the process has been to evaluate the performance of a 237 Np target cermet pellet encased in an aluminum clad. The process proceeded in 3 steps; the first step was to irradiate capsules of single pellets composed of NpO 2 and aluminum power to examine their shrinkage and gas release. These pellets were formed by compressing sintered NpO 2 and aluminum powder in a die at high pressure followed by sintering in a vacuum furnace. Three temperatures were chosen for sintering the solution precipitated NpO 2 power used for pellet fabrication. The second step was to irradiate partial targets composed of 8 pellets in a semi-prototypical arrangement at the two best performing sintering temperatures to determine which temperature gave a pellet that performed the best under the actual planned irradiation conditions. The third step was to irradiate ~50 pellets in an actual target configuration at design irradiation conditions to assess pellet shrinkage and gas release, target heat transfer, and dimensional stability. The higher sintering temperature appeared to offer the best performance after one cycle of irradiation by having the least shrinkage, thus keeping the heat transfer gap between the pellets and clad small minimizing the pellet operating temperature. The final result of the testing was a target that can meet the initial production goals, satisfy the reactor safety requirements, and can be fabricated in production quantities. The current focus of the program is to verify that the target can be remotely dissembled, the pellets dissolved, and the 238 Pu recovered. Tests are being conducted to examine these concerns and to compare results to code predictions. Once the performance of the full length targets has been quantified, the pellet 237 Np loading will be revisited to determine if it can be increased to increase 238 Pu production.

07 ISOTOPE AND RADIATION SOURCES↗