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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Regulatory Perspective on Potential Fuel Reconfiguration and Its Implication to High Burnup Spent Fuel Storage and Transportation - 13042

The recent experiments conducted by Argonne National Laboratory on high burnup fuel cladding material property show that the ductile to brittle transition temperature of high burnup fuel cladding is dependent on: (1) cladding material, (2) irradiation conditions, and (3) drying-storage histories (stress at maximum temperature) [1]. The experiment results also show that the ductile to brittle temperature increases as the fuel burnup increases. These results indicate that the current knowledge in cladding material property is insufficient to determine the structural performance of the cladding of high burnup fuel after it has been stored in a dry cask storage system for some time. The uncertainties in material property and the elevated ductile to brittle transition temperature impose a challenge to the storage cask and transportation packaging designs because the cask designs may not be able to rely on the structural integrity of the fuel assembly for control of fissile material, radiation source, and decay heat source distributions. The fuel may reconfigure during further storage and/or the subsequent transportation conditions. In addition, the fraction of radioactive materials available for release from spent fuel under normal condition of storage and transport may also change. The spent fuel storage and/or transportation packaging vendors, spent fuel shippers, and the regulator may need to consider this possible fuel reconfiguration and its impact on the packages' ability to meet the safety requirements of Part 72 and Part 71 of Title 10 of the Code of Federal Regulations. The United States Nuclear Regulatory Commission (NRC) is working with the scientists at Oak Ridge National Laboratory (ORNL) to assess the impact of fuel reconfiguration on the safety of the dry storage systems and transportation packages. The NRC Division of Spent Fuel Storage and Transportation has formed a task force to work on the safety and regulatory concerns in relevance to high burnup fuel storage and transportation. This paper discusses the staff's preliminary considerations on the safety implication of fuel reconfiguration with respect to nuclear safety (subcriticality control), radiation shielding, containment, the performance of the thermal functions of the packages, and the retrievability of the contents from regulatory perspective. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Comprehensive Fuel Cycle - Community Perspective - 13093

Should a five-county region surrounding the Department of Energy's Savannah River Site ('SRS') use its assets to help provide solutions to closing the nation's nuclear fuel cycle? That question has been the focus of a local ad hoc multi-disciplinary community task force (Tier I) that has been at work in recent months outlining issues and identifying unanswered questions to determine if assuming a leadership role in closing the nuclear fuel cycle is in the community's interest. If so, what are the terms and conditions under which we the community would agree to participate? Our starting point was the President's Blue Ribbon Commission on America's Nuclear Future ('Commission') which made a total of eight (8) recommendations in its final report. There are several recommendations that are directly relevant to the Tier I group and potential efforts of the Region. These are the 'consent-based approach', the creation of an independent nuclear waste management entity funded from the existing nuclear waste fee; the 'prompt efforts to develop one or more consolidated storage facilities', and 'continued U.S. innovation in nuclear energy technology and for workforce development'. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

Blue Ribbon Commission, Yucca Mountain Closure, Court Actions - Future of Decommissioned Reactors, Operating Reactors and Nuclear Power - 13249

Issues related to back-end of the nuclear fuel cycle continue to be difficult for the commercial nuclear power industry and for the decision makers at the national and international level. In the US, the 1982 NWPA required DOE to develop geological repositories for SNF and HLW but in spite of extensive site characterization efforts and over ten billion dollars spent, a repository opening is nowhere in sight. There has been constant litigation against the DOE by the nuclear utilities for breach of the 'standard contract' they signed with the DOE under the NWPA. The SNF inventory continues to rise both in the US and globally and the nuclear industry has turned to dry storage facilities at reactor locations. In US, the Blue Ribbon Commission on America's Nuclear Future issued its report in January 2012 and among other items, it recommends a new, consent-based approach to siting of facilities, prompt efforts to develop one or more geologic disposal facilities, and prompt efforts to develop one or more consolidated storage facilities. In addition, the March 2011 Fukushima Daiichi accident had a severe impact on the future growth of nuclear power. The nuclear industry is focusing on mitigation strategies for beyond design basis events and in the US, the industry is in the process of implementing the recommendations from NRC's Near Term Task Force. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

A Rinsing Effluent Evaporator for Dismantling Operations - 13271

Between 1958 and 1997, the UP1 plant at Marcoule - located in the south of France - reprocessed and recycled nearly 20,000 MT of used fuel from special defense applications reactors, as well as fuel from the first generation of electricity generating reactors in France (natural uranium fuel, CO{sub 2}-cooled, graphite-moderated). Decommissioning and Dismantling of the UP1 plant and its associated units started in 1998. Since 2005, the UP1 facility has been operated by AREVA as the Marcoule Management and Operation contractor for French Atomic Energy Commission (CEA). An important part of this decommissioning program deals with the vitrification facility of Marcoule. This facility includes 20 tanks devoted to interim storage of highly active solutions, prior to vitrification. In 2006, a rinsing program was defined as part of the tank cleanup strategy. The main objective of the rinsing phases was to decrease activity in order to limit the volume of 'long-life active' waste produced during the decommissioning operations, so the tanks can be dismantled without the need of remote operations. To enable this rinsing program, and anticipating large volumes of generated effluent, the construction of an evaporation unit proved to be essential. The main objective of this unit was to concentrate the effluent produced during tank rinsing operations by a factor of approximately 10, prior to it being treated by vitrification. The evaporator design phase was launched in September 2006. The main challenge for the Project team was the installation of this new unit within a nuclear facility still in operation and in existing compartments not initially designed for this purpose. Cold operating tests were completed in 2008, and in May 2009, the final connections to the process were activated to start the hot test phase. During the first hot test operations performed on the first batches of clean-up effluent, the evaporator had a major operating problem. Extremely large quantities of foam were produced, affecting the evaporator operation, and creating the risk of a reduction in its capacity and throughput performance. A task force of AREVA process, operations, and safety experts from Marcoule and the La Hague reprocessing complex was assembled. New operating parameters were defined and tested to improve the process. Since then, the evaporator has performed very satisfactorily. The foam buildup phenomenon has been brought under complete control. All the different types of effluents produced during cleanup operations have been concentrated, and the results obtained in terms of quality and throughput, have ensured a consistent supply to the vitrification unit. The evaporator was operated until the end of April 2012, and enabled the production of 500 cubic meters of very high activity effluent, concentrating the fission products rinsed from the storage tanks. The evaporator will now be deactivated and decommissioned, with the first rinsing and cleanup operations scheduled to begin in 2014. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

GSI 191 Closure Issue for EDF PWR Fleet: The Fuel Assembly Test Results

EDF has re started recirculation studies within the international GSI 191 framework by 2002, when EDF decided to join the NEI sump strainers task force. All the EDF PWR fleet have been upgraded, with major strainer modifications, according to the NEI 04-07 guideline. The so-called chemical effects have been carefully studied by EDF and demonstration have been released that there are no chemical effects on EDF fleet, owing to the nature of our debris. The study of strainer downstream effects started by 2009, with decoupling Downstream Sump Debris Source Term (DST) and by the end of 2016, all the equipment have been successfully qualified. At a previous ANS meeting,it was said that core fuel tests were scheduled. They have started at the beginning of 2014 and they have been closed by mid 2016 for AREVA Fuel type at ERLANGEN facility (Germany). The present presentation is aimed at describing the test facility, the test specifications and the main results. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Decarbonizing Building Thermal Systems: A How-to Guide for Heat Pump Systems and Beyond

Buildings account for a substantial portion of carbon emissions, primarily due to the widespread use of fossil fuels in heating systems. Decarbonization of heating is essential to meet climate targets and reduce the environmental impact of buildings. Heat pumps are capable of leveraging renewable energy sources and can provide heating and cooling in an energy-efficient manner. By leveraging heat pump technology, buildings can significantly reduce their carbon footprint, minimize energy consumption, and decrease their reliance on fossil fuels. The design and construction community plays a pivotal role in facilitating the transition to heat pump systems for heating and cooling. However, this transition requires specialized knowledge and expertise. This resource was developed for architects, engineers, and contractors in response to an industry need for a comprehensive technical resource that guides them through the intricacies of heat pump system design, installation, and maintenance. This resource provides detailed information on system sizing, selection of appropriate heat systems, heat sources, and integration with existing building systems. Moreover, it emphasizes best practices for ensuring operational efficiency, system longevity, and reliability. The development of this recourse was a collaborative effort between NREL/DOE Better Buildings Design and Construction Allies and ASHRAE Task Force for Building Decarbonization. This resource is composed of two complimentary portions that will be completed and released on separate time frames. The first portion will be completed and released in 2023, while the second portion will be released in 2024.

building thermal systems↗
DOE OSTI2024

The New Face of Standard 100

In January 2024, ASHRAE published a significant overhaul to ANSI/ASHRAE/IES Standard 100-2018, Energy Efficiency in Existing Buildings. You may almost not recognize it. Standard 100-2024, Energy and Emissions Building Performance Standard for Existing Buildings, now addresses both energy and emissions performance as a model building performance standard (BPS). ASHRAE Standing Standard Project Committee (SSPC) 100, with direction from ASHRAE and its Task Force for Building Decarbonization (TFBD) has been working to update the standard to make it a model for building performance standard adoption across the U.S. and internationally. Here, the new edition of Standard 100 addresses key issues of climate change surrounding building performance, including new metrics for greenhouse gas (GHG) emissions targets, continuing to support the imperative of improving our existing building stock and meeting global climate change commitments.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1983

Definition of Forces on Turbomachinery Rotors. Task B Report: Dynamic Analysis of Rotors

The rotordynamic characteristics of turbomachinery are known to depend on the forces developed due to relative motion between the rotor and the housing. For example, the critical speed locations generally depend on the bearing stiffnesses, seal dampling influences rotor stability and bearing reaction amplitudes near critical speeds, etc. A systematic examination of the influence of changes in the forces acting on rotors is studied. More specifically, the sensitivity of the rotordynamic characteristics to changes in rotor forces is analyzed. Rotordynamic characteristics of the HPOTP (High Pressure Oxygen Turbopump) and HPFTP (High Pressure Fuel Turbopump) of the SSME (Space Shuttle Main Engine) are investigated. Because of their markedly different rotordynamic characteristics, these units are considered to be representative of a range of possible future liquid rocket engine turbomachinery.

Childs, D. W.↗
NASA NTRS1990

Stereo advantage for a peg-in-hole task using a force-feedback manipulator

An improved assessment methodology has been implemented at NOSC and tested using an instrumented peg-in-hole (PiH) taskboard. Several aspects of the methodology are discussed in light of their implications for future studies of manipulator performance. Using a simple (but high-fidelity) force-feedback manipulator, a group of 9 trained operators showed a consistent advantage for stereoscopic TV viewing over monoscopic TV viewing when performing the PiH task. To introduce a controlled element of spatial uncertainty into the testing procedure, taskboard orientation relative to the manipulator and remote video camera head was changed in a randomized order on a trial-by-trial basis. The stereoscopic advantage demonstrated by this study can reasonably be expected to be even more pronounced as the quality of the stereo TV interface is improved and force-feedback provided through the manipulator system is diminished and/or distorted.

Spain, Edward H.↗
NASA NTRS1987

Consolidated fuel reprossing program: The implications of force reflection for teleoperation in space

Previous research on teleoperator force feedback is reviewed and results of a testing program which assessed the impact of force reflection on teleoperator task performance are reported. Force relection is a type of force feedback in which the forces acting on the remote portion of the teleoperator are displayed to the operator by back-driving the master controller. The testing program compared three force reflection levels: 4 to 1 (four units of force on the slave produce one unit of force at the master controller), 1 to 1, and infinity to 1 (no force reflection). Time required to complete tasks, rate of occurrence of errors, the maximum force applied to tasks components, and variability in forces applied to components during completion of representative remote handling tasks were used as dependent variables. Operators exhibited lower error rates, lower peak forces, and more consistent application of forces using force relection than they did without it. These data support the hypothesis that force reflection provides useful information for teleoperator users. The earlier literature and the results of the experiment are discussed in terms of their implications for space based teleoperator systems. The discussion described the impact of force reflection on task completion performance and task strategies, as suggested by the literature. It is important to understand the trade-offs involved in using telerobotic systems with and without force reflection.

Draper, John V.↗
NASA NTRS1992

Evaluation Of Performance Of A Telerobot

Paper presents evaluation of performance of six-axis telerobot system with shared control and advanced modes of force feedback. Various tasks performed with and without force feedback. Study found force feedback reduces average time required to complete task by about 30 percent. Also reduces sum of squared forces by factor of 7 and errors by 63 percent.

Hannaford, Blake↗
DOE OSTI2026

An adaptive model-free robotic force control strategy for hydrodynamic real-time hybrid simulation of floating offshore wind turbines

Real-time hybrid simulation (RTHS) - a cyber-physical testing approach - promises to enhance the simulation fidelity of the model-scale experiments used to prototype floating offshore wind turbines (FOWTs). In hydrodynamic RTHS (hydro-RTHS), actuators emulate aerodynamic forces on model-scale FOWT specimens subjected to physical waves in a hydrodynamic laboratory. Robotic arms are promising candidates for actuation in hydro-RTHS due to their compact multi-degree-of-freedom (DOF) capabilities. Unlike classical RTHS for seismic applications, which typically relies on displacement control, hydro-RTHS requires 6-DOF force control on newly designed floating prototypes in a model-scale setting, which presents significant challenges, including modeling uncertainties, directional asymmetry, configuration drift, bandwidth limitations, and time-varying delays. To mitigate these constraints without extensive pre-test calibration, this study proposes an adaptive model-free robotic force control strategy that combines task-space explicit force control with a secondary joint-space pose-keeping task. The Adaptive Feedforward Compensator (AFC) is integrated into the force control loop to compensate for time-varying delay. Experimental testing was conducted using a Franka Emika Panda robotic arm with a 1:50 scale FOWT specimen under operational wind and wave conditions. Results demonstrate stable and consistent 6-DOF force tracking. Effective delay compensation was observed, with low-frequency delay reductions ranging from 71.4% to 91.8% and improvements in low-frequency surge force tracking of 25.0% to 52.1%. This study enhances robotic actuation performance in hydro-RTHS and introduces a force control strategy that supports reliable robotic operation in uncertain floating environments. Future work will explore disturbance-observer mechanisms to further enhance wave rejection capabilities under extreme wind and wave conditions.

17 WIND ENERGY↗
NASA NTRS1972

Study of astronaut restraints and mobility aids in a weightless shirtsleeve environment

A study, established to produce needed information about manual performance limits in intravehicular weightlessness such as the motions induced by the astronaut's direct application of force against the body of the vehicle or an object to be moved, is presented. Using both conventional and water immersion techniques, it was possible to develop realistic time estimates for astronaut station-to-station translation in Skylab, to simulate and analyze specific Skylab tasks involving force application and motion dynamics, and to evaluate certain thresholds of force application in weightlessness. The study was divided into three tasks. The first related to locomotion and verification or modification of present Skylab translation timelines. In all cases, translation times were less than the Skylab timelines indicated. The second task studied mass handling and transfer. Specifically, this involved measurement of the astronaut's ability to relocate the Skylab food lockers to stowage levels of three different heights and his ability to transfer the M509 PSS bottles between the OWS and the recharge station. The third task helped define the physical limits of man's ability to perform Skylab translation tasks under weightless conditions.

Loats, H. L., Jr.↗
NASA NTRS1991

Impact of inertia, friction, and backlash upon force control in telemanipulation

The mechanical behavior of master controllers of telemanipulators has been a concern of both designers and implementors of telerobotic systems. In general, the literature recommends that telemanipulator systems be constructed that minimize inertia, friction, and backlash in an effort to improve telemanipulative performance. For the most part, these recommendations are founded upon theoretical analysis or simply intuition. Although these recommendations are not challenged on their merit, the material results are measured of building and fielding telemanipulators that possess less than ideal mechanical behaviors. Experiments are described in which forces in a mechanical system with human input are evaluated as a function of mechanical characteristics such as inertia, friction, and backlash. Results indicate that the ability of the human to maintain gripping forces was relatively unaffected by dynamic characteristics in the range studied, suggesting that telemanipulator design in this range should be based on task level force control requirements rather than human factors.

Duffie, Neil A.↗
DOE OSTI2024

"Soiling, Cleaning, and Abrasion: The Results of the Five-Year Photovoltaic Glass Coating Field Study" [Slides]

External contamination ("soiling") of the incident surface is a major limiting factor for solar technologies. A 5-year field glass coupon study was conducted to better understand external contamination and its effects; compare cleaning methods and the use of preventative coatings; and explore the abrasion resulting from cleaning to advise on accelerated abrasion testing. Test sites included the cities of Dubai (UAE), Kuwait City (Kuwait), Mesa (AZ), Mumbai (India), and Sacramento (CA). Through the 5-year cumulative study, dry brush, water spray, and wet sponge and squeegee cleaning methods were compared to no cleaning. Optical microscopy was used to obtain images, including representative color images, grayscale images for object analysis, and oblique images for coating integrity assessment. A thresholding protocol was developed to analyze and distinguish specimens using the ImageJ software. Optical performance was quantified using a spectrophotometer, including comprehensive optical characterization (transmittance, reflectance, and absorptance in addition to forward- and back-scattering). Atomic force microscopy was used to verify the abrasion damage morphology, including the width and depth of surface scratches. Analysis of the results included correlation of optical performance and particle area coverage, rank order (by coating or location), and the acceleration factor for abrasion damage. The efficacy of external cleaning was more readily distinguished from the effectiveness of antisoiling coatings. The acceleration factor for dry brush cleaning of a porous silica coating was found to be on the order of unity.

14 SOLAR ENERGY↗
DOE OSTI2024

Photovoltaic Cable Connectors: A Comparative Assessment of the Present State of the Industry

The consequences of failure for balance-of-systems components (such as photovoltaic (PV) cable connectors) include offline module string(s); low system voltage; arc, ground, insulation, and overtemperature faults; triggered fuse(s); system shutdown; and fire. The degradation modes for connectors are studied here through an industry survey and its subsequent examination, which are compared with field-degraded specimens. A total of 117 specimens were obtained from a variety of locations and climates or accelerated tests. A failure analysis for connectors from PV installations was developed (and applied to 54 specimens), including nondestructive examinations (photography, a custom resistance-current scan, and X-ray computed tomography) and destructive examinations (featuring milling of the external plastic, extraction of the internal convolute spring, and potting and polishing in cross section). Surface and through-thickness composition of the metal pins and springs was quantified using scanning electron microscopy with energy-dispersive X-ray spectroscopy. Fourier transform infrared spectroscopy was used to verify the base polymer materials and compare the chemical structure of the connector body, bushing, end nut, and o-ring. Thermogravimetric analysis and differential scanning calorimetry were used to further verify the degradation of the same polymeric components.

cable connectors↗