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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

NASA Engineering and Safety Center Lunar Rover Design Concepts Assessments

Mass is a significant risk to programs and projects as they transition from formulation to implementation, especially in larger human space systems where delivery mass or volume can be a constrained commodity. • Concepts developed without an adequate systems-engineering basis, including design and operations experience, may miss significant functionality and subsequent mass required for integration or operations. • Further uncertainty can be associated with not fully understanding design best practices and standards that drive mass, such as design for minimum risk or fault tolerance.1 • Finally, the appropriate systems engineering mass properties management rigor and technical discipline insight are required to set the mass baseline, including appropriate mass growth allowance (MGA) to ensure program success. Mass is a key quantity that should be constantly monitored by the systems engineer and the program/project management stakeholder to ensure mission compatibility throughout the project life cycle. In addition, mass is a key programmatic performance metric monitored by the NASA Chief Financial Officer for current and future program cost estimating. NASA Exploration Systems sought an assessment of reasonableness with respect to different potential rover concepts that balances mass needs and human-class cargo lander capabilities. Appropriate systems engineering mass properties management rigor and technical discipline insight were used, and are required to set the mass baseline, including appropriate MGA to ensure program success. Two independent Lunar rover concepts were evaluated, with a goal to understand concept credibility and the Lunar rover designs potential extensibility for Mars surface operations. A notional generic rover concept is shown in Figure 1.

Systems Engineering↗
NASA NTRS2008

Integrating Safety and Mission Assurance in Design

This presentation describes how the Ares Projects are learning from the successes and failures of previous launch systems in order to maximize safety and reliability while maintaining fiscal responsibility. The Ares Projects are integrating Safety and Mission Assurance into design activities and embracing independent assessments by Quality experts in thorough reviews of designs and processes. Incorporating Lean thinking into the design process, Ares is also streamlining existing processes and future manufacturing flows which will yield savings during production. Understanding the value of early involvement of Quality experts, the Ares Projects are leading launch vehicle development into the 21st century.

Cianciola, Chris↗
DOE OSTI2023

Stress characterization for friction-stir-welded electric vehicle battery trays with application of neutron diffraction

The battery tray is an essential component that protects and controls battery-cell temperatures in electric and plug-in hybrid vehicles. The functional stress limit of the battery tray heavily depends on the residual stress acquired from the manufacturing process. Consequently, exceeding the stress limit of the battery tray during operation could compromise the battery-cell banks and may risk the vehicle's safety. Hence, understanding residual stress formation is vital for design and safety concerns. Here, in the current study, AA 6061-plates were friction stir welded to an A365 high-pressure die-cast battery tray to create sealed coolant channels in the battery tray. However, this multi-material lap friction stir weld introduces residual stress into the battery tray, resulting in distortion. This distortion was mitigated using burnishing or coining operations, though straightening the battery tray had initially unknown effects on the residual stress. Therefore, neutron diffraction was utilized to characterize residual stresses after straightening. The results indicate that the friction stir welding (FSW) operation generated residual stresses exceeding the yield strength of the material, consequently deforming the battery tray by ±3 mm from the pre-weld geometry. The burnishing operation reduced the residual stresses below the material's yield strength while restoring the tray to within ±0.75 mm of the pre-weld geometry. Similarly, the coining operation restored the battery tray to within ±0.75 mm of the pre-weld geometry, however, increasing the number of locations where the residual stress exceeds the yield strength of the material.

36 MATERIALS SCIENCE↗
NASA NTRSDate not supplied

Exploring Methods to Collect and Analyze Data on Human Contributions to Aviation Safety: A Panel Discussion

Focusing on undesired operator behaviors is pervasive in system design and safety management cultures in aviation. This focus limits the data that are collected, the questions that are asked during data analysis, and therefore our understanding of what operators do in everyday work. Human performance represents a significant source of aviation safety data that includes both desired and undesired actions. When safety is characterized only in terms of errors and failures, the vast majority of human impacts on system safety and performance are ignored. The outcomes of safety data analyses dictate what is learned from those data, which in turn informs safety policies and safety-related decision making. When learning opportunities are systematically restricted by focusing only on rare failure events, not only do we learn less (and less often), but we can draw misleading conclusions by relying on a non-representative sample of human performance data. Changes in how we define and think about safety can highlight new opportunities for collection and analysis of safety-relevant data. Developing an integrated safety picture to better inform safety-related decision making and policies depends upon identifying, collecting, and interpreting safety-producing behaviors in addition to safety-reducing behaviors. Opportunities and challenges in collecting and analyzing the largely unexploited data on desired, safety-producing operator behaviors are discussed.

Aviation Safety↗
NASA NTRSDate not supplied

Exploring Methods to Collect and Analyze Data on Human Contributions to Aviation Safety: A Panel Discussion

Focusing on undesired operator behaviors is pervasive in system design and safety management cultures in aviation. This focus limits the data that are collected, the questions that are asked during data analysis, and therefore our understanding of what operators do in everyday work. Human performance represents a significant source of aviation safety data that includes both desired and undesired actions. When safety is characterized only in terms of errors and failures, the vast majority of human impacts on system safety and performance are ignored. The outcomes of safety data analyses dictate what is learned from those data, which in turn informs safety policies and safety-related decision making. When learning opportunities are systematically restricted by focusing only on rare failure events, not only do we learn less (and less often), but we can draw misleading conclusions by relying on a non-representative sample of human performance data. Changes in how we define and think about safety can highlight new opportunities for collection and analysis of safety-relevant data. Developing an integrated safety picture to better inform safety-related decision making and policies depends upon identifying, collecting, and interpreting safety producing behaviors in addition to safety reducing behaviors. The panel will discuss opportunities and challenges in collecting and analyzing the largely unexploited data on desired, safety-producing operator behaviors.

aviation safety↗
DOE OSTI2023

Risk Analysis of Various Design Architectures for High Safety-significant Safety-related Digital Instrumentation and Control Systems of Nuclear Power Plants during Accident Scenarios

This report documents the plus-up activities performed by Idaho National Laboratory (INL) during Fiscal Year (FY) 2022 for the U.S. Department of Energy (DOE) Light Water Reactor Sustainability (LWRS) Program, Risk Informed Systems Analysis (RISA) Pathway, digital instrumentation and control (DI&C) risk assessment project. In FY 2019, the RISA Pathway initiated a project to develop a risk assessment strategy for delivering a strong technical basis to support effective, licensable, and secure DI&C technologies for digital upgrades/designs. An integrated risk assessment technology for the DI&C systems was proposed for this strategy, which aims to (1) provide a best-estimate, risk-informed capability to quantitatively and accurately estimate the safety margin obtained from plant modernization, especially for the high safety-significant safety-related (HSSSR) DI&C systems, (2) support and supplement existing advanced risk-informed DI&C design guides by providing quantitative risk information and evidence, (3) offer a capability of design architecture evaluation of various DI&C systems to support system design decisions and diversity and redundancy applications, (4) assure the long-term safety and reliability of HSSSR DI&C systems, and (5) reduce uncertainty in costs and support integration of DI&C systems in the plant. To achieve these technical goals and deal with the expensive licensing justifications from regulatory insights, the LWRS-developed framework instructs nuclear vendors and utilities on how to effectively lower the costs associated with digital compliance and speed industry advances by: (1) defining an integrated risk-informed analysis process for DI&C upgrade, including hazard analysis, reliability analysis, and consequence analysis, (2) applying systematic and risk-informed tools to address common cause failures (CCFs) and quantify corresponding failure probabilities for DI&C technologies, particularly software CCFs, (3) evaluating the impact of digital failures at the component level, system level, and plant level, and (4) providing insights and suggestions on designs to manage the risks, thus to support the development, licensing, and deployment of advanced DI&C technologies on nuclear power plant (NPPs). Adding diversity within system or components is the main means to eliminate and mitigate CCFs, but diversity also increases plant complexity and errors and may not address all sources of systematic failures. How to optimize the diversity and redundancy applications for the safety-critical DI&C systems remains a challenge. To deal with the technical issues in addressing potential software CCFs in HSSSR DI&C systems of NPPs and supporting relevant design optimization, the framework provides: ? An integrated best-estimate, risk-informed capability to address new technical digital issues quantitatively, accurately, and efficiently in plan modernization progress, such as software CCFs in HSSSR DI&C systems of NPPs ? A common and a modularized platform for DI&C designers, software developers, cybersecurity analysts, and plant engineers to efficiently predict and prevent risk in the early design stage of DI&C systems ? Technical bases and risk-informed insights to assist U.S. Nuclear Regulatory Commission (NRC) and industry to address and fulfill the risk-informed alternatives for evaluation of CCFs in HSSSR DI&C systems of NPPs ? An integrated risk-informed tool that offers a capability of design architecture evaluation of various DI&C systems to support system design decisions in diversity and redundancy applications. The plus-up research and development efforts of this project in FY 2022 are focused on methodology improvement of software CCF modeling and estimation, prevention analysis, importance analysis and risk analysis of various design architectures of HSSSR DI&C systems. This work greatly enhances the capability of the LWRS-developed framework for the risk assessment and design optimization of safety-critical DI&C systems. It should be noted that all the analyses are performed for the demonstration of the LWRS-developed framework, not for the evaluation of relevant systems. Results are obtained based on very limited design information and testing data.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2024

RFA-17-14597, Methodology for Meeting Containment System Principal Design Criteria to Maximize the Passive Safety Value in Advanced Nuclear Energy Economic Competitiveness

Advanced (Non-Light Water) Reactors are being designed with Passive Safety as an essential and integral feature. To help streamline the licensing of advanced reactors, the DOE and the NRC have drafted Principal Design Criteria (PDCs) for advanced reactors. A question that remains to be answered is: how an Advanced Reactor take credit for passive safety features inherent in certain advanced reactors while at the same time complying the evolving PDC.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS2024

Workshop on the Role of Design Assurance in System-Wide Safety’s Safety Demonstrator Series

This report summarizes a three-hour hybrid in-person/online workshop on June 7, 2024 on the topic of design assurance and the Safety Demonstrator Series (SDS), which was held at NASA Ames Research Center. The SDS provides an operational demonstration of, and recommendations for, requirements and standards necessary to monitor, assess, and mitigate risks to assure safety in disaster-oriented operations. Over sixty NASA personnel participated in the workshop. Four main topics were discussed: (1) assurance needs for the Safety Demonstrator Series, (2) assurance and the In-Time Aviation Safety Management System (IASMS), (3) in-time assurance: existing efforts and future opportunities, and (4) demonstrating assurance tools in the Safety Demonstrators. Key takeaways are as follows: 1. Design assurance tools can be used to assure an In-Time Aviation Safety Management System, the systems that comprise it, and other systems or missions. Assurance must consider both systems and components and include the interactions between elements in both a systems/aircraft context and a systems-of-systems/airspace context. 2. Design-time assurance activities can support the identification of monitors needed for operational assurance activities (i.e., the “monitor” function in the monitor-assess-mitigate paradigm at the heart of the IASMS concept). 3. A major opportunity for design-time assurance tools to contribute to the IASMS concept is to support rapid re-validation of systems. This will be particularly important for (1) supporting novel operations in the IASMS, where operational data may disprove design-time assumptions (motivating re-analysis of system safety) and (2) adapting technologies (e.g., AI/ML for autonomous operations) to new operational domains, where there may be new or different safety considerations not included in the initial scope of operations. 4. There are several design assurance tools under development in the System-Wide Safety project that can support assurance of Services, Functions, and Capabilities (SFCs) in the Safety Demonstrators. Transitioning these tools from one-off research projects into a functioning part of IASMS assurance will require closer integration between these tools. 5. It is not clear whether the role of design assurance tools is primarily as a part of IASMS architecture or as an external check on IASMS. The workshop consisted of four discussion topics initiated via four lightning talks by System-Wide Safety researchers. Discussions utilized Mural to engage both in-person and online participants in the hybrid format. Polls and surveys were also utilized to gather participant input. The workshop closed with a reflection activity for participants, as well as new ideas for collaboration and coordination of ongoing System-Wide Safety research.

design assurance↗
DOE OSTI2022

A SIMPLE TOOL TO EVALUATE COLOR FOR LEGIBILITY AND DISTINGUISHABILITY WHEN DESIGNING DIGITAL DISPLAYS

Color is important in helping users effectively process information like text and symbols when performing tasks on digital displays. Interface designers in safety- and mission-critical industries often utilize human factors design guidelines and standards to make important design decisions like the use of color for legibility and distinguishability. However, such guidance sometimes requires additional interpretation and calculation to readily apply to the design question at hand. This work describes a simple tool that can be used to evaluate the adequacy of color choices from a palette for being legible or distinguishable. The tool eliminates having to manually convert colors to a readable format while providing a specific set of colors that are acceptable from select human factors standards. This paper provides an exemplary case study applied to a digital modification at a nuclear power plant to highlight how the tool may be used in safety and mission-critical industries.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2025

Engineering Design Report: High-Pressure Safety Squib

This project encompassed the mechanical portion of the squib system and included the design and analysis of the valve body, selection of tube and tube fittings, valve mounting, and initiator/detonator selection. The electrical portion of the squib has already been designed by another team and is outside of the scope of the project. Electrical information and requirements provided are only for use in selecting a compatible detonator/initiator.

42 ENGINEERING↗
NASA NTRS1973

Directory of aerospace safety specialized information sources

A directory is presented to make available to the aerospace safety community a handbook of organizations and experts in specific, well-defined areas of safety technology. It is designed for the safety specialist as an aid for locating both information sources and individual points of contact (experts) in engineering related fields. The file covers sources of data in aerospace design, tests, as well as information in hazard and failure cause identification, accident analysis, materials characteristics, and other related subject areas. These 171 organizations and their staff members, hopefully, should provide technical information in the form of documentation, data and consulting expertise. These will be sources that have assembled and collated their information, so that it will be useful in the solution of engineering problems. One of the goals of the project in the United States that have and are willing to share data of value to the aerospace safety community.

Fullerton, E. A.↗
DOE OSTI2025

Forced flow transient safety analysis of irradiation device with adjustable orifice for research reactor fuel assemblies

The Belgium Reactor 2 (BR2) of the Belgian Nuclear Research Centre (SCK CEN) has several irradiation devices or rigs that are dedicated to the fuel performance and qualification demonstration testing of research reactor fuels. In support of the U.S. High Performance Research Reactor (USHPRR) LEU conversion project, a new flexible irradiation apparatus, MUSTANG-R, has been constructed. SCK CEN has completed the design and safety study, in cooperation with Idaho National Laboratory (INL) and Argonne National Laboratory (ANL), to allow for the irradiation testing of a full-size fuel assembly in a 200 mm diameter channel in the BR2 reactor. The moveable valve is a key design feature of the device and acts like an adjustable orifice enhancing or restricting the flow through a coolant channel inlet located in the BR2 upper plenum. This moveable valve allows the flow through the device to be adjusted prior to each BR2 cycle to obtain the necessary conditions for the fuel qualification test. This ensures accurate and representative thermal-hydraulic conditions of the fuel design are achieved. The device was designed and qualified as passively safe, implying verification by a combination of mechanical and thermal-hydraulic analysis and testing. This includes characterization of the safety margin required for a scenario where the moveable valve is assumed to be erroneously closed during irradiation. A simplified and conservative method is proposed for analyzing the corresponding forced flow transient using a critical heat flux criterion. In conclusion, this allows the required minimum valve opening to be determined for the experiments' design and safety studies.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1985

Space shuttle external tank performance improvements: The challenge

The external tank (ET) has been actively involved in performance improvements since the inception of the space shuttle program, primarily by weight savings. Weight savings were realized on the first block of flight articles (standard weight tank). With a need for further performance improvements, the ET Program Office was requested to develop a program to reduce tank weight an additional 6000 lb and schedule delivery of the first lightweight ET (LWT) for June 1982. The weight savings program was accomplished by: (1) a unique approach to use of factors of safety; (2) design optimization; and (3) redesign of structures with large margins of safety which resulted in an actual weight savings of 7294 lb. Additional studies have identified further weight savings which are to be implemented at appropriate times in production flow. Examples are an improved thermal protection system for the LH2 tank aft dome and reduction of slosh baffles in the LO2 tank based on flight data. All performance improvements were compared and selected based on non-recurring and recurring cost and technical risk.

Coldwater, H. R.↗
NASA NTRS1986

Safety considerations of lithium-thionyl chloride cells

The use of spirally wound lithium-thionyl chloride (Li-SOCl2) cells is currently limited because of their hazardous behavior. Safety hazards have ranged from mild venting of toxic materials to violent explosions and fires. These incidents may be related to both user- and manufacturer-induced causes. Many explanations have been offered to explain the unsafe behavior of the cells under operating and abuse conditions. Explanations fall into two categories: (1) thermal mechanisms, and (2) chemical mechanisms. However, it is quite difficult to separate the two. Both may be responsible for cell venting or explosion. Some safety problems encountered with these cells also may be due to design deficiencies and ineffective quality control during cell fabrication. A well-coordinated basic and applied research program is needed to develop safe Li-SOCl2 cells. Recommendations include: (1) learnig more about Li-SOL2 cell chemistry; (2) modeling cell and battery behavior; (3) optimizing cell design for safety and performance, (4) implementing quality control procedures; and (5) educating users.

Subbarao, Surampudi↗
NASA NTRS2009

Ares I Static Tests Design

Probabilistic engineering design enhances safety and reduces costs by incorporating risk assessment directly into the design process. In this paper, we assess the format of the quantitative metrics for the vehicle which will replace the Space Shuttle, the Ares I rocket. Specifically, we address the metrics for in-flight measurement error in the vector position of the motor nozzle, dictated by limits on guidance, navigation, and control systems. Analyses include the propagation of error from measured to derived parameters, the time-series of dwell points for the duty cycle during static tests, and commanded versus achieved yaw angle during tests. Based on these analyses, we recommend a probabilistic template for specifying the maximum error in angular displacement and radial offset for the nozzle-position vector. Criteria for evaluating individual tests and risky decisions also are developed.

Carson, William↗
DOE OSTI2022

Liquid Hydrogen Heavy-Duty Vehicle Safety Review and Refueling Facility Design

Liquid hydrogen (LH 2 ) used as a fuel onboard a heavy-duty vehicle can result in increased storage capacity and faster refueling relative to compressed gas. However, there are concerns about hydrogen losses from boil-off, potential safety issues, gaps in codes and standards for cryogenic hydrogen fuel, and technical challenges with LH 2 systems for widespread transportation applications. A failure modes and effects analysis (FMEA), a safety codes and standards review, and a design review of the onboard liquid hydrogen system for a heavy-duty vehicle identified some of these potential safety issues and gaps in the codes and standards. The FMEA identified some medium and low risk failure points of the conceptual design, and the design review identified how carefully pressure relief needs to be considered for LH 2 systems. In addition, a conceptual design for a LH 2 refueling station was developed. Rough capital costs for the refueling station design were $\$1 million$ and the layout occupied approximately 13,000 ft 2 . These results can be used to inform future designs and analyses for LH 2 heavy-duty vehicles.

08 HYDROGEN↗
NASA NTRS2016

Human Factors Checklist: Think Human Factors - Focus on the People

A quick-look Human Factors (HF) Checklist condenses industry and NASA Agency standards consisting of thousands of requirements into 14 main categories. With support from contractor HF and Safety Practitioners, NASA developed a means to share key HF messages with Design, Engineering, Safety, Project Management, and others. It is often difficult to complete timely assessments due to the large volume of HF information. The HF Checklist evolved over time into a simple way to consider the most important concepts. A wide audience can apply the checklist early in design or through planning phases, even before hardware or processes are finalized or implemented. The checklist is a good place to start to supplement formal HF evaluation. The HF Checklist was based on many Space Shuttle processing experiences and lessons learned. It is now being applied to ground processing of new space vehicles and adjusted for new facilities and systems.

Human Factors; Human Systems Integration↗