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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

Probabilistic Guidance of a Swarm Deployed from the Back Shell of the Mars Spacecraft

This paper presents a probabilistic guidance algorithm for a swarm of assets deployed from the back shell of the Mars spacecraft. Such a swarm could provide valuable science data, with large spatiotemporal variation, from the Martian surface. Our probabilistic swarm guidance algorithm maximizes the coverage area of the swarm while uniformly distributing the assets on the Martian surface and guaranteeing strong connectivity of the swarm’s communication network topology. Numerical simulations demonstrate the effectiveness and versatility of our probabilistic swarm guidance algorithm.

Hadaegh, Fred↗
NASA NTRSDate not supplied

Demonstration of Linear Covariance Analysis Techniques to Evaluate Entry Descent and Landing Guidance Algorithms, Vehicle Configurations, Analysis Techniques, and Trajectory Profiles

Linear covariance analysis techniques have been previously developed to analyze closed-loop entry, descent, and landing (EDL) scenarios and the initial validation efforts are under-way confirming the generated GN&C system performance results. Given both the theoretical foundation and previous conceptual demonstration, this work begins to flex the potential of linear covariance analysis for atmospheric flight and highlight its versatility and reliability by evaluating multiple entry guidance algorithms, vehicle configurations, trajectory profiles, environment conditions, and analysis techniques for a variety of trade studies. To demonstrate the benefit linear covariance analysis can provide in producing rapid yet accurate performance data, two entry profiles are adopted including the NASA Mars Science Laboratory (MSL) and Exploration Flight Test-1 (EFT-1) while utilizing two different guidance algorithms, the Apollo Final Phase (AFP) and the Fully Numeric Predictor-Corrector Entry Guidance (FNPEG) with different navigation sensor suites in a 6 degree-of-freedom (6-DOF) simulation environment. Results are shown using both linear covariance and Monte Carlo analysis techniques to high-light the consistency between the two methodologies and continue the validation maturation of linear covariance analysis for entry, descent, and landing.

EDL↗
NASA NTRS2021

Stochastic Guidance of Buoyancy Controlled Vehicles under Ice Shelves using Ocean Currents

We propose a novel technique for guidance ofbuoyancy-controlled vehicles in uncertain under-ice ocean flows.In-situ melt rate measurements collected at the grounding zoneof Antarctic ice shelves, where the ice shelf meets the underlyingbedrock, are essential to constrain models of future sea levelrise. Buoyancy-controlled vehicles, which control their verticalposition in the water column but have no means of horizontalpropulsion, offer an affordable and reliable platform for suchin-situ data collection. However, reaching the grounding zonerequires vehicles to traverse tens of kilometers under the iceshelf, with approximate position knowledge and no meansof communication, in highly variable and uncertain oceancurrents. To address this challenge, we propose a partiallyobservable MDP approach that exploits model-based knowledgeof the under-ice currents and, critically, of their uncertainty,to synthesize effective guidance policies. The approach usesapproximate dynamic programming to model uncertainty inthe currents, and QMDP to address localization uncertainty.Numerical experiments show that the policy can deliver upto 88.8% of underwater vehicles to the grounding zone – a33% improvement compared to state-of-the-art guidance techniques, and a 262% improvement over uncontrolled drifters.Collectively, these results show that model-based under-iceguidance is a highly promising technique for exploration ofunder-ice cavities, and has the potential to enable cost-effectiveand scalable access to these challenging and rarely observed environments.

Clark, Evan B.↗
NASA NTRS2024

Revisiting Optimal Guidance Solution for Vertical Landing and Take-Off

The vertical landing and take-off are crucial phases of a rocket-powered spacecraft's powered descent and ascent trajectories, during which its motion is confined to a single (vertical) axis. It is well-known that the minimum-propellant guidance solutions for vertical landing and take-off in a vacuum, consist of only one coast and one full-thrust arc and no singular arc exists in these problems. However, an exact solution for the vertical descent problem is not found in the literature. In the present work, exact guidance solutions for the optimal vertical landing and take-off are presented that are valid for arbitrary boundary conditions. The time-based and switching function-based guidance law implementations are discussed and their performance is compared using lunar descent and ascent simulations.

powered descent↗
DOE OSTI2017

Surgical guidance system using hand-held probe with accompanying positron coincidence detector

A surgical guidance system offering different levels of imaging capability while maintaining the same hand-held convenient small size of light-weight intra-operative probes. The surgical guidance system includes a second detector, typically an imager, located behind the area of surgical interest to form a coincidence guidance system with the hand-held probe. This approach is focused on the detection of positron emitting biomarkers with gamma rays accompanying positron emissions from the radiolabeled nuclei.

Majewski, Stanislaw↗
DOE OSTI2019

NETL CO2U LCA Guidance Toolkit - Version 1.0.1

The NETL CO2U LCA Guidance Toolkit is part of the NETL CO2U LCA Guidance Toolkit for Carbon Utilization funding recipients to meet their LCA requirements. The toolkit includes the following files: NETL CO2U LCA Guidance Document, NETL CO2U openLCA LCI Database, NETL CO2U openLCA Results Contribution Tool, NETL CO2U LCA Documentation Spreadsheet, and NETL CO2U LCA Report Template.<br>Note: This zip file may take a few minutes to download.

Source record↗
DOE OSTI2019

CO2 Utilization Life Cycle Analysis (LCA) Guidance at the U.S. Department of Energy

This work was presented at the CO2 Utilization Summit in Houston, TX on February 27, 2019. In the interest of supporting the creation of useful LCAs of CO2 utilization projects, DOE is developing guidance, data, and tools for CO2 utilization LCA. Working with actual CO2 utilization projects funded under FOAs, DOE is providing specific guidance on methodological issues and choosing a comparison system. DOE is also providing upstream and downstream data that is relevant to CO2 utilization projects. The guidance, data, and tools will be publicly available and free.

Cooney, Gregory↗
DOE OSTI2020

NETL CO2U LCA Guidance Toolkit - Version 1.0.0

The NETL CO2U LCA Guidance Toolkit is part of the NETL CO2U LCA Guidance Toolkit for Carbon Utilization funding recipients to meet their LCA requirements. The toolkit includes the following files: NETL CO2U LCA Guidance Document, NETL CO2U openLCA LCI Database, NETL CO2U openLCA Results Contribution Tool, NETL CO2U LCA Documentation Spreadsheet, and NETL CO2U LCA Report Template.<br>Note: this zip file may take a few minutes to download.

Source record↗
DOE OSTI2021

Moving from scientific research to consenting guidance for MRE environmental risk

Potential environmental effects from tidal and wave devices are of concern to regulators, advisors, and other stakeholders in many nations. Monitoring results from early deployments and the first commercial arrays, coupled with targeted research studies, are providing a growing base of knowledge of how components of tidal turbines and wave energy converters might interact with marine animals and habitats. Efforts are underway to organize and direct these findings towards facilitating consenting that allays concerns and allows the marine renewable energy (MRE) industry to move forward. The OES-Environmental international initiative has developed scientific evidence bases for several key interactions from MRE devices, organized around stressors (portions of MRE systems that may cause injury or stress to the marine ecosystem), and receptors (the animals, habitats, and ecosystem processes that may be affected). This paper summarizes the evidence bases for four stressors (underwater noise, electromagnetic fields, habitat change, and changes in oceanographic systems) and presents the process of moving from the scientific knowledge into guidance documents to support the regulatory process. The guidance documents will serve as a broad guide that can be used internationally to look at stressor-receptor interactions of interest within a regulatory context. The evidence bases and guidance documents aim to assist MRE developers, regulators, and advisors with project scoping, consenting, and licensing processes.

Copping, Andrea E.↗
DOE OSTI2017

EPRI Guidance for Transitioning from Operation to Decommissioning at Nuclear Power Plants - 17438

A wide range of key activities are necessary after permanent shutdown of a nuclear power plant and before active dismantlement of the plant can begin. This period between permanent shutdown and the start of active dismantlement is typically referred to as the transition period (or the post-operational phase). In some cases, these transition activities may be prescribed by regulation or performed in the absence of regulations, while in other cases they may be more practically driven or even optional. In either case, it is often unclear what activities are needed and when/how those activities should be conducted to most efficiently transition from operational to decommissioning status while maintaining radiological safety and the protection of the public. The Electric Power Research Institute has prepared a report that presents experiences and guidance for transitioning from an operational to decommissioning status based on US and international decommissioning regulations and plant experiences. Regulations and experiences in a number of countries were considered, including US, Germany, France, Spain, and Switzerland. Best practices and lessons learned related to transitioning to decommissioning are identified, and guidance is presented for developing a plan to transition from normal operations to decommissioning for several scenarios, including: - Transition to DECON (immediate dismantling) for a planned shutdown; - Transition to SAFSTOR (deferred dismantling) for a planned shutdown; - Transition to DECON (immediate dismantling) for an unplanned shutdown; - Transition to SAFSTOR (deferred dismantling) for an unplanned shutdown. Further, the EPRI report contains guidance for currently operating plants that do not anticipate permanent shutdown in the near future to help minimize the cost and impact of an unexpected permanent shutdown if such a scenario were to occur. (authors)

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

Development of criticality safety validation guidance for NRC-regulated activities

Some guidance documents support validation of criticality safety evaluations for many system types, and some accommodate different regulators or regulatory requirements. While these reports address specific applications, no single document applies to all systems and incorporates both traditional and sensitivity/uncertainty-based validation techniques. Oak Ridge National Laboratory will develop a single reference report for the US Nuclear Regulatory Commission (NRC) that provides modern examples and suggested recommendations for a uniform approach for performing and documenting k{sub eff} calculation validations applicable to any system containing fissile material. The project will include a literature review and development of a new, comprehensive NUREG/CR document on nuclear criticality safety validation. The NUREG will address the following experiences from recent reviews: 1) Inappropriate critical experiment selection; 2) Insufficient trending analysis; 3) Incorrectly calculated 95/95 uncertainties; 4) Failure to address how validation applies to safety analysis; 5) Lack of goodness-of-fit testing in trending analyses; 6) Incorrect use of commercial reactor critical data; 7) Failure to meet bias determination methodology prerequisites; 8) Inappropriate extrapolation of bias and uncertainty; 9) Failure to identify validation analysis gaps and weaknesses; and 10) Inadequate validation analysis documentation. The final report will provide guidance on use of trending analysis results, acceptable confidence levels for normality testing and trending analysis, management of validation analysis gaps and weaknesses, use of sensitivity and uncertainty analysis in validation analysis, and potential impact of correlations among critical experiments used in validation. It will also consolidate existing guidance documents using both traditional and sensitivity/uncertainty-based approaches. This document will support NRC-regulated activities, as well as validation used in criticality safety within other regulatory frameworks. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

Value Based Decision Approach to Help Inform Waste Management Guidance for VLLW Following an RDD Detonation - 19510

The detonation of a radiological dispersal device in an urban environment or similar large-scale radiological event has the potential to spread radioactive contamination over a large area. The resulting effort to clean up and dispose of this waste will involve input and coordination from a wide variety of stakeholder groups, especially if the waste crosses municipal and state boundaries. Guidance designed to help effectively and safely deal with the wastes generated from incident cleanup will need to navigate the intersection of stakeholders at the local, regional, and national levels. At the same time, the sheer size of such a cleanup effort and the volumes of wastes generated will require innovative and potentially novel solutions compared to current Low-Level Radioactive Waste disposal practices. A structured decision-making approach incorporating value-focused thinking is one method that could be employed to help build stakeholder confidence in a given cleanup guidance strategy and documentation. This approach would help ensure that all stakeholder perspectives were accounted for in a given decision situation and to promote transparency in the decision-making process. This paper will discuss research into the role and development of a public stakeholder tool used to gather input from relevant stakeholders in order to help inform cleanup and disposal guidance of Very Low-Level Radioactive Waste following a radiological disaster. This tool is being designed to draw on aspects of value-focused decision making. Case studies from two prominent recent events will be discussed to illustrate some of the key issues that could benefit from such an approach to stakeholders. (authors)

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

Guidance Development: Management of Low Activity Waste After a Radiological Incident - 19616

The EPA, as the coordinating federal agency for long-term environmental recovery under the National Response Framework, is considering working with other Federal agencies, states and others to develop planning guidance for the management of the large volumes of waste that could result from a radiological incident. The 2017 revision of the PAG Manual contained, for the first time, limited generalized planning guidance on waste disposal; however, more detailed guidance that supports federal, state, and local planning efforts and can be initiated at the earliest stages of an incident would be desirable. This paper provides some of the considerations that EPA is exploring. (authors)

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

Lessons Learned in the Development of Industry Guidance - 20279

The availability of industry guidance on different aspects of waste management forms a valuable reference for waste practitioners. The guidance typically details the principles, processes and practices that should be consulted during each stage of the relevant activities. It also includes relevant regulatory and international requirements, appropriate case studies and examples of best practices to illustrate technical concepts and make the information available to the reader in an accessible manner. Over recent years Wood have developed (or are developing) a number of industry guidance documents on a range of topics including Solid Waste Characterization, Routine Water Quality Monitoring on Nuclear Sites: Pipeline Characterization: Determining Background Radioactivity for Land Quality Assessment: Interim Storage and Aqueous Waste Management. This talk provides an overview of lessons learned along the way including: - the importance of stakeholder engagement through the process: - how to identify 'good practice'; - the importance of iterative development; and - the selection of illustrative and informative case studies. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Development of MELCOR 2.1 Guidance Report for LPF Applications

A complex nuclear facility includes several pathways that can transport accidentally released materials throughout the facility and potentially to the exterior environment. To model and estimate material transport and possible release as a source term from a U.S. Department of Energy (DOE) nuclear facility requires proficiency in applying simulation tools, such as the MELCOR code. DOE has designated MELCOR version 1.8.5, an obsolete version, as a DOE Tool Box code in its Central Registry. A leak path factor (LPF) guidance report written in 2004 did not include experimental validation data. Using an obsolete version of MELCOR requires additional verification and validations, which may be cost prohibitive. Without any developer support and lack of experimental data validation, it is difficult to justify to regulators that the calculated source term with the obsolete version of MELCOR from the facility is accurate and defensible. The goal of this work is to replace the obsolete guidance report with MELCOR 2.1 with experimental validations. In this paper, we will present our approach to develop a MELCOR 2.1 guidance report for LPF applications. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗