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NASA NTRSDate not supplied

Probabilistic Approach to Assessing CCRS Capture System Performance Margin

In the aerospace industry, there are standard design principles and/or rule-of-thumb targets that define healthy levels of margins required at each developmental milestone for traditional metrics, such as mass, thermal, and power margins. When the technical resource is “non-traditional” in the sense that guiding margin principles are non-existent, systems engineering judgment is required to internally generate performance targets and methodologies to assess the system against the derived targets. This paper presents a probabilistic approach for assessing complex time-critical operations in order to apply global sensitivity analyses to identify input parameters that should (or should not) serve as design drivers.

Performance Margins↗

NASA NTRSDate not supplied

EMU Helmet Free Water Transport Assessment for the HAB in Support of Eva 80

After water was reported in the EMU helmet during ISS US EVA-80, mitigation strategies were created to attempt to arrest the motion of any droplets that enter the helmet for future Extravehicular Activities (EVAs). This included adding absorbent materials into the interior of the helmet. To assess the effectiveness of this strategy, a computational fluid dynamics (CFD) model of a human mannikin head in the EMU helmet was used to track water droplets and quantify how much water is likely to be caught by the absorbent material. A combination of engineering judgment, tests, and CFD results were used to develop the expected path of droplets in the helmet, to account for the simplifications necessary in modeling two-phase flow.

Abigail Baukus↗

NASA NTRSDate not supplied

LSKnowledge: Nexus for Transformative Scientific Discoveries and Enhanced Information Retrieval in NASA Life Sciences Portal

We stand at the brink of an extraordinary transformation in the field of AI, driven by the convergence of generative AI and semantic technologies (e.g., knowledge graphs). This fusion holds immense potential and could redefine the future of scientific exploration, particularly in the realm of life sciences research. In this context, we shed light on the pivotal roles that Large Language Models (LLMs) and semantic technologies will play in advancing research, unearthing and comprehending life sciences information through innovative approaches, and empowering researchers to extract insights from NASA's extensive Life Sciences Data Archive. Within the NASA Life Sciences Portal (NLSP), the integration of LLMs and semantic technologies unlocks several advanced capabilities. First and foremost, it equips scientists with sophisticated tools to manage the ever-expanding wealth of scientific literature and data. Furthermore, it facilitates the creation of knowledge graphs that visually represent intricate relationships among biological entities, enabling comprehensive systems-level analysis. Additionally, the fusion of generative AI (including LLMs) and semantic technology can significantly benefit NASA's life sciences research by enhancing information retrieval and hypothesis generation. These tools enhance natural language understanding, facilitating knowledge discovery within NLSP. The overarching vision is to establish a cohesive knowledge ecosystem within NLSP, harnessing the power of LLMs and semantic technologies to synthesize and cross-reference data from diverse missions, disciplines, and research domains. This holistic approach ultimately deepens our understanding of how space environments impact life sciences data. To advance this initiative, we have launched LSKnowledge, aimed at enhancing the information retrieval capabilities of NLSP. In the short term, our primary goal is to develop a robust semantic search system. This system will empower HRP (Human Research Program) researchers to navigate NLSP data repositories more efficiently and precisely, catalyzing the process of hypothesis formation and scientific breakthroughs. To achieve this, we have employed pre-trained LLMs as part of a semantic search tool that can rank and highlight the most relevant records for user queries. To assess the tool's performance, we have curated a set of approximately 200 queries from subject matter experts (SMEs) and manually ranked the top records retrieved by both the current search system and the new semantic search, using SME judgments as the gold standard for relevancy. Herein, we present the results of our comparative analysis and illustrate how these findings have informed the fine-tuning of the system for enhanced performance. In the long term, our objectives include 1) retrieving publicly available information and integrating it with NLSP data to provide more precise answers to user queries, and 2) incorporating non-textual information from the NLSP database into our approach. In conclusion, the fusion of LLMs and semantic technologies within NLSP represents a pioneering stride towards reshaping the landscape of scientific discovery. This synergy not only equips researchers with powerful tools to navigate the burgeoning sea of information but also facilitates a deeper understanding of complex biological relationships, all while accelerating hypothesis generation and knowledge discovery. Through our initiative, LSKnowledge, we are committed to continually refining and expanding these capabilities, with the aim of not only enhancing information retrieval but also integrating diverse data sources to provide more precise insights. In the grand vision, NLSP strives to become the cornerstone of a comprehensive knowledge ecosystem, unraveling the enigmatic intricacies of life sciences phenomena in the context of space environments.

Life Sciences↗

NASA NTRSDate not supplied

Distortion of Perceived Visual Space after Eccentric Gaze Holding

Previous studies have shown that rebound nystagmus can be a behavioral probe into the adaptive properties of the gaze-holding mechanism, showing that after prolonged eccentric gaze holding and upon return to central gaze the eye tends to drift towards the previously held position. It is not known whether perception of visual space is also affected by similar adaptation mechanisms. The current study seeks to elucidate if eccentric gaze holding changes the perception of space in a relative spatial judgment task. To measure their spatial bias, twelve subjects were asked to report which among two short vertical lines flashed to the left or to the right of the display was closer to a third central line. Perception was assessed after holding eccentric gaze at 40 degrees towards the left or right and compared with control trials without eccentric gaze holding. Subjects showed a significant difference in spatial bias between the leftward and rightward gaze holding conditions (p = 0.04), suggesting that the visual space changes differently with respect to the side where gaze was held. While we did not observe an overall bias (p = 0.327) under no gaze holding we did observe a significant correlation between handedness and spatial bias (r2 = 0.4, p = 0.04). We conclude that gaze holding temporarily distorts the perception of space in a mechanism that may be related to the adaptation of the gaze holding mechanism.

perception↗

DOE OSTI2015

Combined Sustainability Assessment and Techno-Economic Analysis for the Production of Biomass-Derived High-Octane Gasoline Blendstock

Conversion technologies for biomass to liquid hydrocarbon fuels are being actively developed. Converting biomass into advanced hydrocarbon fuels requires detailed assessments to help prioritize research; techno-economic analysis (TEA) is a long established tool used to assess feasibility and progress. TEA provides information needed to make informed judgments about the viability of any given conceptual conversion process; it is particularly useful to identify technical barriers and measure progress toward overcoming those barriers. Expansion of the cellulosic biofuels industry at the scale needed to meet the Renewable Fuel Standard goals is also expected to have environmental impacts. Hence, the success of the biofuels industry depends not only on economic viability, but also on environmental sustainability. A biorefinery process that is economically feasible but suffers from key sustainability drawbacks is not likely to represent a long-term solution to replace fossil-derived fuels. Overarching concerns like environmental sustainability need to be addressed for biofuels production. Combined TEA and environmental sustainability assessment of emerging pathways helps facilitate biorefinery designs that are both economically feasible and minimally impactful to the environment. This study focuses on environmental sustainability assessment and techno-economic analysis for the production of high-octane gasoline blendstock via gasification and methanol/dimethyl ether intermediates. Results from the conceptual process design with economic analysis, along with the quantification and assessment of the environmental sustainability, are presented and discussed. Sustainability metrics associated with the production of high-octane gasoline include carbon conversion efficiency, consumptive water use, life-cycle greenhouse gas emissions, fossil energy consumption, energy return on investment and net energy value.

09 BIOMASS FUELS↗

DOE OSTI2016

Spreadsheet Assessment Tool v. 2.4

The Spreadsheet Assessment Tool (SAT) is an easy to use, blast assessment tool that is intended to estimate the potential risk due to an explosive attack on a blood irradiator. The estimation of risk is based on the methodology, assumptions, and results of a detailed blast effects assessment study that is summarized in Sandia National Laboratories Technical Report SAND2015-6166. Risk as defined in the report and as used in the SAT is: "The potential risk of creating an air blast-induced vent opening at a buildings envelope surface". Vent openings can be created at a buildings envelope through the failure of an exterior building component—like a wall, window, or door—due to an explosive sabotage of an irradiator within the building. To estimate risk, the tool requires that users obtain and input information pertaining to the building's characteristics and the irradiator location. The tool also suggests several prescriptive mitigation strategies that can be considered to reduce risk. Given the variability in civilian building construction practices, the input parameters used by this tool may not apply to all buildings being assessed. The tool should not be used as a substitute for engineering judgment. The tool is intended for assessment purposes only.

Allen, David J.↗

DOE OSTI2016

Exploring Effective Decision Making through Human-Centered and Computational Intelligence Methods

Decision-making has long been studied to understand a psychological, cognitive, and social process of selecting an effective choice from alternative options. Its studies have been extended from a personal level to a group and collaborative level, and many computer-aided decision-making systems have been developed to help people make right decisions. There has been significant research growth in computational aspects of decision-making systems, yet comparatively little effort has existed in identifying and articulating user needs and requirements in assessing system outputs and the extent to which human judgments could be utilized for making accurate and reliable decisions. Our research focus is decision-making through human-centered and computational intelligence methods in a collaborative environment, and the objectives of this position paper are to bring our research ideas to the workshop, and share and discuss ideas.

collaboration↗

DOE OSTI2017

Document Set Differentiability Analyzer v. 0.1

Software is a JMP Scripting Language (JSL) script designed to evaluate the differentiability of a set of documents that exhibit some conceptual commonalities but are expected to describe substantially different – thus differentiable – categories. The script imports the document set, a subset of which may be partitioned into an additions pool. The bulk of the documents form a basis pool. Text analysis is applied to the basis pool to extract a mathematical representation of its conceptual content, referred to as the document concept space. A bootstrapping approach is applied to that mathematical representation in order to generate a representation of a large population of randomly designed documents that could be written within the concept space, notably without actually writing the text of those documents.The Kolmogorov-Smirnov test is applied to determine whether the basis pool document set exhibits superior differentiation relative to the randomly designed virtual documents produced by bootstrapping. If an additions pool exists, the documents are incrementally added to the basis pool, choosing the best differentiated remaining document at each step. In this manner the impact of additional categories to overall document set differentiability may be assessed.The software was developed to assess the differentiability of job description document sets. Differentiability is key to meaningful categorization. Poor job differentiation may have economic, ethical, and/or legal implications for an organization. Job categories are used in the assignment of market-based salaries; consequently, poor differentiation of job duties may set the stage for legal challenges if very similar jobs pay differently depending on title, a circumstance that also invites economic waste.The software can be applied to ensure job description set differentiability, reducing legal, economic, and ethical risks to an organization and its people. The extraction of the conceptual space to a mathematical representation enables identification of exceedingly similar documents. In the event of redundancy, two jobs may be collapsed into one. If in the judgment of the subject matter experts the jobs are truly different, the conceptual similarities are highlighted, inviting inclusion of appropriate descriptive content to explicitly characterize those differences. When additional job categories may be needed as the organization changes, the software enables evaluation of proposed additions to ensure that the resulting document set remains adequately differentiated.

Osborn, Thor D.↗

DOE OSTI2018

Experts’ Familiarity Versus Optimality of Visualization Design: How Familiarity Affects Perceived and Objective Task Performance

Experts, cutting across domains like biology, climate science, cyber, energy, etc., frequently use visualizations as the principal medium for making analytical judgments or for presenting the results of their analysis. However, scientists are often skeptical about adopting new visualization methods over familiar ones, although the latter might be perceptually sub-optimal. This is due to the use of the familiarity heuristic, where the perceived cognitive ease in processing familiar representations of information leads scientists to undermine the effect of visualization best practices. Recent studies have shown that this often results in a discrepancy between scientists’ perceived and actual performance quality. It has also been shown that in some cases, participatory design sessions and qualitative and quantitative user studies are able to mitigate the effects of such bias. In this paper, we discuss the potential causes and effects of familiarity related biases with examples from recent studies and reflect on the related research questions.

visualization, climate science, cognitive bias, fa↗

DOE OSTI2018

UNCERTAINTY QUANTIFICATION OF CALCULATED FUEL TEMPERATURE FOR AGR-3/4 IRRADIATION EXPERIMENT

The third in a series of Advanced Gas Reactor (AGR) experiments conducted at the Idaho National Laboratory, AGR-3/4, was completed in April 2014, resulting in irradiation of the tristructural isotropic fuel for 369 effective full power days. A number of designed-to-fail fuel particles were embedded along the central line of each irradiated compact to provide a known source of fission products for subsequent transport through the compact matrix and structural graphite materials. The fuel temperature in each capsule during irradiation, a significant factor in the release and transport of fission products, was maintained within a predefined range representative of a high temperature gas reactor. Fuel temperatures were not measured directly because contact between a thermocouple and the fuel could lead to unwanted particle failures. An ABAQUS-based finite element heat transfer code, calibrated based on temperatures measured in the surrounding graphite rings, was used to predict fuel temperatures during irradiation. To quantify the uncertainty of calculated fuel temperatures, thermal model parameters with high sensitivity and/or large uncertainty were identified. Propagation of model parameter uncertainty and sensitivity is then used to quantify the overall uncertainty of calculated temperatures. Quantification of input uncertainties over the extended irradiation period of the AGR-3/4 experiment is a challenging task due to changes in capsule thermal properties and geometry caused by exposure to neutron irradiation at high temperatures. In the absence of direct measurements or complete knowledge about these changes, inputs to thermal model and associated uncertainties are estimated based on modeling assumptions and expert judgment. Unplanned events that occurred during irradiation contribute to input uncertainties as well. For example, shrinkage of fuel compact and graphite rings led to significant increase in the gap size uncertainties. This paper focuses on uncertainty quantification of calculated fuel temperature for AGR-3/4 capsule thermal models.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2020

FEMP Facility Evaluation (Audit) Decision Tree

This document is a resource to be used in concert with FEMP Audit Definitions, FEMP Consolidated Facility Management Guidance, and agency best practices and expert judgment—for agencies to use to determine the best approaches to evaluate their facilities. It features a decision tree that provides a framework for agencies to interpret gathered facility data to understand the existing conditions; benchmark the facility against others in the portfolio to determine whether an on-site or remote audit is appropriate for a facility; determine the best remote or on-site audit level of detail to meet agency facility auditing goals, such as meeting Energy Independence and Security Act of 2007 requirements and developing projects; and improve their energy and water management programs.

auditing↗

DOE OSTI2018

Quantifying the Contribution of Individual Display Features on Mental Workload to Support Human-System Interface Design in Nuclear Power Plants

Abstract. The integration of new digital instrumentation and control (I&C) technologies like advanced human-system interfaces in U.S. nuclear power plant main control rooms is important for addressing long-term aging and obsolescence of existing I&C. Nonetheless, attention should be made to ensure these technologies reflect state-of-the-art human factors engineering (HFE) principles. Often, there is conflicting guidance from one guideline to another, requiring the analyst to make a judgment call on addressing these 'tradeoffs.' The objective of this research was to inform the analyst of these tradeoffs through an empirical investigation of how certain display features that characterize common HFE guidelines concerning visual clutter and saliency influence information processing in a naturalistic context. By understanding the unique contribution of each display feature using a multilevel model, the HFE analyst should have an understanding of the interrelations of each feature with its impact on cognitive processes. Results and implications are discussed in this paper.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2018

OPTIMIZATION OF FAST FISSION GAS RELEASE MODEL PARAMETERS USING MACHINE LEARNING ACCELERATED EVOLUTIONARY ALGORITHMS

Fission gas release models used in FRAPCON and FAST are based on equations that describe the physical transport phenomena that control release from the fuel pellet to the rod void volume of fission gas produced during irradiation. Although these models are physically based, many of the parameters that control the release such as the impact of burnup on diffusion and bubble formation and saturation are critical to the accurate prediction of fission gas release, but cannot be measured in any quantitative way. To overcome this problem, these parameters have been empirically derived to provide a best fit to the available data that includes rod puncture data and electron probe microanalysis (EMPA) and X-ray fluorescence (XRF) data of radial location of residual gas within the pellet. In general, a heuristic approach for deriving these parameters via practical implementation of expert analyses on just a few dependent variables has been shown to perform quite well in most situations. In this paper, we present an approach for applying machine learning to expedite model development. This approach is based on developing a deep artificial neural network which describes FRAPCON’s fission gas release models, and optimizes parameters by a differential evaluation algorithm. This approach allows us to quickly and accurately tune physical models based on expert judgment, and works as a human-in-the-loop approach, to assist the modeler in identifying and addressing regions of high uncertainty in a multi-parameter space. Results of the updated fission gas release model will be shown for all the FAST assessment data.

Johns, Jesse M.↗

DOE OSTI2021

Apparatus and method for safety analysis evaluation with data-driven workflow

An apparatus and method for system safety analysis evaluation is provided, the apparatus including processing circuitry configured for generating a calculation matrix for a system, generating a plurality of models based on the calculation matrix, performing a benchmarking or convolution analysis of the plurality of models, identifying a design envelope based on the benchmarking or convolution analysis, deriving uncertainty models from the benchmarking or convolution analysis, deriving an assessment judgment based on the uncertainty models and acceptance criteria, defining one or more limiting scenarios based on the design envelope, and determining a safety margin in at least one figure-of-merit for the system based on the design envelope and the acceptance criteria.

Martin, Robert P.↗

DOE OSTI2022

Uncertainty Quantification of Calculated Temperatures for the AGR 5/6/7 Experiment

This report documents the quantification of uncertainty of the calculated temperature data for the Advanced Gas Reactor (AGR) 5/6/7 fuel irradiation experiment conducted in the Advanced Test Reactor at Idaho National Laboratory in support of the Advanced Reactor Technologies? research and development program. Recognizing uncertainties inherent in physics and thermal simulations of the AGR 5/6/7 capsules, the results of the numerical simulations are used in combination with statistical analysis methods to improve qualification of measured data. The calculated fuel temperatures for AGR tests are also used for validation of the fission product transport and fuel performance simulation models. These crucial roles of the calculated fuel temperatures in ensuring achievement of the AGR experimental program objectives require accurate determination of the model temperature uncertainties. This report covers temperature uncertainty results for each of the five AGR 5/6/7 capsules. To quantify the uncertainty of calculated temperatures determined using the ABAQUS finite element heat transfer code, this study identifies and analyzes model parameters of potential importance to the calculated temperatures of fuel compacts and thermocouples. The selection of input parameters for uncertainty quantification is based on the ranking of their influences upon temperature predictions. Thus, selected input parameters include those with high sensitivity and those with the largest uncertainty. Propagation of model parameter uncertainty and sensitivity is then used to quantify the overall uncertainty of calculated temperatures. Measurement uncertainty, analysis of modeling assumptions, and expert judgment are used as the basis to quantify the uncertainty range for selected input parameters. The input uncertainties are dynamic, accounting for the effect of unplanned events and changes in thermal properties of capsule components over extended exposure to high temperatures and fast neutron irradiation. The sensitivity analysis performed in this work went beyond the traditional local sensitivity. Using experimental design, analysis of pairwise interactions of model parameters was performed to establish sufficiency of the time dependent first order (linear) expansion terms in constructing the temperature response surface. To achieve completeness, uncertainty propagation made use of pairwise noise correlations of model parameters. Furthermore, using an interpolation scheme over the input parameter domain, the analysis obtains time dependent sensitivity over the test campaign duration. This allows computation of uncertainty for the calculated fuel temperatures and the calculated graphite temperatures at thermocouple locations during the entire irradiation period.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2023

Apparatus and method for safety analysis evaluation with data-driven workflow

Martin, Robert P.↗

DOE OSTI2023

The Future of Visualization Technology Vis in Practice

Two decades ago, we witnessed an inflection point as graphics programming became commoditized. A comparable inflection point may be on the horizon, this time driven by the commoditization of immersive display technology with Augmented Reality (AR), Virtual Reality (VR), and Extended Reality (XR) technologies poised to redefine our interaction with data, environments, and collaboration. To drive the technology and its application, we should consider the lessons learned from successful large-scale immersive installations. Where these installations have thrived is by enhancing traditional workflows rather than entirely replacing them, supporting improved judgments of complex spaces, direct interaction in 3D, and embedding high-dimensional data.

AR/VR↗

DOE OSTI2015

A study of transfer of UNF from non-disposable canisters - 15388

A study was performed by AREVA and URS for the Department of Energy (DOE) [1] to establish optimal methods for the opening of dry storage canisters (DSC) and the subsequent repackaging of used nuclear fuel (UNF) from the DSCs into generic standard transportation, aging, and disposal canisters (STADs) in wet or dry environments at reactor, consolidated storage, or repository sites. Eight dry and wet cutting technologies were evaluated: (1) skiving; (2) milling; (3) arc gouging/plasma torch; (4) cutting wheel; (5) diamond cable cutting; (6) laser cutting; (7) sawing; and (8) electrical discharge machining. The evaluated UNF repackaging technologies options included: (1) wet transfer in a pool; (2) dry transfer in a dry transfer system (DTS); (3) dry transfer in a fixed hot cell (FHC); (4) dry transfer in a mobile hot cell (MHC), and (5) a hybrid approach utilizing wet transfer in a pool and dry transfer in a FHC. A systems engineering evaluation was utilized for ranking the eight viable cutting options and the five different repackaging approaches for each of the sites. The systems engineering evaluation took into account six criteria (i.e., life cycle costs, worker dose, operational efficiency, technical maturity, ease of licensing, and waste generation) and performed a qualitative pairwise ranking of their relative importance to one another. Then quantitative or qualitative factors associated with each criterion (e.g., cost in millions of dollars, relative ease of licensing, etc.) for each option at each location (reactor, consolidated storage facility [CSF], repository) were developed based on historical experience, existing design studies, current 'state-of-the art', and/or engineering judgment. Using this input, the systems engineering evaluation identified dry skiving as the preferred cutting technology, with the wheel cutting technology in either a dry or wet environment identified as a promising technology that, with some RD and D, could mature to a better option (depending also on the disposition of the used DSC). For a reactor and a CSF/repository site, the systems engineering evaluation ranked the repackaging option using the skiving dry cutting technique and wet transfer of UNF in a pool as the highest option. However for a CSF and a repository site, the team recommended the hybrid option using the skiving dry cutting technique and both dry and wet transfer of UNF in a pool and FHC as a potentially better option (providing specific benefits such as higher throughput and more flexibility in operation). (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗