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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS2008

Hydrogen Research for Spaceport and Space-Based Applications: Hydrogen Sensors and Systems

The activities presented are a broad based approach to advancing key hydrogen related technologies in areas such as fuel cells, hydrogen production, and distributed sensors for hydrogen-leak detection, laser instrumentation for hydrogen-leak detection, and cryogenic transport and storage. Presented are the results from research projects, education and outreach activities, system and trade studies. The work will aid in advancing the state-of-the-art for several critical technologies related to the implementation of a hydrogen infrastructure. Activities conducted are relevant to a number of propulsion and power systems for terrestrial, aeronautics and aerospace applications. Sensor systems research was focused on hydrogen leak detection and smart sensors with adaptive feedback control for fuel cells. The goal was to integrate multifunction smart sensors, low-power high-efficiency wireless circuits, energy harvesting devices, and power management circuits in one module. Activities were focused on testing and demonstrating sensors in a realistic environment while also bringing them closer to production and commercial viability for eventual use in the actual operating environment.

Anderson, Tim↗
DOE OSTI2020

Monitoring the Possible Effects of Corroding Fuel Cladding in Nuclear Ponds: a Modified ROV for Storage Ponds - 20144

Nuclear ponds are used worldwide to store radioactive nuclear material, often for extended periods of time. The pond water conditions need to be closely monitored so that mitigation strategies can be put in place should any leakage of radioactive material occur. This paper describes the selection, development and on-site deployment of a bespoke system whose design was based on of-the-shelf components. The system is able to identify, locate and differentiate the leakage of radioactive material stored in nuclear ponds from the background activity of the water in the pond. The selection of an appropriate detector and monitoring geometry was supported by MCNP modelling which allowed a high degree of confidence in the proposed design. The development of the system allowed a real-time indication of the canister integrity, without incurring the increased operator doses from manual sampling operations that were previously used on site. The benefits of the developed system include the fact that the system is lightweight, easily deployable, retrievable, decontaminable and results in negligible waste products. Moreover, it is able to analyse the samples in-situ, in this way reducing the time needed to manually collect and send the samples to a laboratory for lengthy analysis. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1973

Examination of T-111 clad uranium nitride fuel pins irradiated up to 13,000 hours at a clad temperature of 990 C

The examination of 27 fuel pins irradiated for up to 13,000 hours at 990 C is described. The fuel pin clad was a tantalum alloy with uranium nitride as the nuclear fuel. Two nominal fuel pin diameters were tested with a maximum burnup of 2.34 atom percent. Twenty-two fuel pins were tested for fission gas leaks; thirteen pins leaked. Clad ductility tests indicated clad embrittlement. The embrittlement is attributed to hydrogen from an n,p reaction in the fuel. Fuel swelling was burnup dependent, and the amount of fission gas release was low, generally less than 0.5 percent. No incompatibilities between fuel, liner, and clad were in evidence.

Slaby, J. G.↗
NASA NTRS1993

The development of hydrogen sensor technology at NASA Lewis Research Center

The detection of hydrogen leaks in aerospace applications, especially those involving hydrogen fuel propulsion systems, is of extreme importance for reasons of reliability, safety, and economy. Motivated by leaks occurring in liquid hydrogen lines supplying the main engine of the Space Shuttle, NASA Lewis has initiated a program to develop point-contact hydrogen sensors which address the needs of aerospace applications. Several different approaches are being explored. They include the fabrication of PdAg Schottky diode structures, the characterization of PdCr as a hydrogen sensitive alloy, and the use of SiC as a semiconductor for hydrogen sensors. This paper discusses the motivation behind and present status of each of the major components of the NASA LeRC hydrogen sensor program.

Hunter, Gary W.↗
NASA NTRS2015

Color Changing Hydrogen Sensors

During the Space Shuttle Program, one of the most hazardous operation that occurred was the loading of liquid hydrogen (LH2) during fueling operations of the spacecraft. Due to hydrogen's low explosive limit, any amount leaked could lead to catastrophic event. Hydrogen's chemical properties make it ideal as a rocket fuel; however, the fuel is deemed unsafe for most commercial use because of the inability to easily detect the gas leaking. The increased use of hydrogen over traditional fossil fuels would reduce greenhouse gases and America's dependency on foreign oil. Therefore a technology that would improve safety at NASA and in the commercial sector while creating a new economic sector would have a huge impact to NASA's mission. The Chemochromic Detector for sensing hydrogen gas leakage is a color-changing detector that is useful in any application where it is important to know not only the presence but also the location of the hydrogen gas leak. This technology utilizes a chemochromicpigment and polymer matrix that can be molded or spun into rigid or pliable shapes useable in variable temperature environments including atmospheres of inert gas, hydrogen gas, or mixtures of gases. A change in color of the detector material indicates where gaseous hydrogen leaks are occurring. The irreversible sensor has a dramatic color change from beige to dark grey and remains dark grey after exposure. A reversible pigment changes from white to blue in the presence of hydrogen and reverts back to white in the presence of oxygen. Both versions of the sensor's pigments were comprised of a mixture of a metal oxide substrate and a hydro-chromic compound (i.e., the compound that changed color in the presence of hydrogen) and immediately notified the operator of the presence of low levels of hydrogen. The detector can be used in a variety of formats including paint, tape, caulking, injection molded parts, textiles and fabrics, composites, and films. This technology brings numerous benefits over the traditional hydrogen sensors: The technology has excellent temperature stability (4K to 373 K), it can be used in cryogenic fluid applications, it is easy to apply and remove; it requires no power to operate; it has a quick response time; the leak points can be detected visually or electronically; it is nonhazardous, thus environmentally friendly; it can be reversible or irreversible; it does not require on-site monitoring; has a long shelf life; the detector is very durable; and the technology is inexpensive to manufacture.

Chemochromic sensor↗
DOE OSTI2024

Fabrication and Testing of DOE Standard Canister Closure Leak Test Assembly

DOE manages over 300 types of SNF, most of which are located at the INL site. “Road-ready dry storage” is a management concept where SNF is packaged into dry, sealed canisters, which are then placed in on-site storage in anticipation of later removal. The Idaho Cleanup Project and INL are collaborating on the Road-Ready Capability Demonstration Project, which will develop and demonstrate the designs, technology, processes, and regulatory framework for packaging DOE SNF for road-ready dry storage. In support of establishing a large-scale road-ready dry storage program at the INL site, the demonstration will package a select amount of DOE-managed SNF into DOE Standard Canisters. The closure process for the DOE Standard Canisters will include fuel and basket loading, welding, inspection, leak testing, and if needed, repair. As a follow-up to previous discussion on the design of the DOE Closure Leak Test Assembly, this report describes recent fabrication and testing efforts performed at INL. DOE Standard Canisters are sealed by two sequential gas tungsten arc welds. Both are performed by remotely operated and semi-autonomous welding systems. The first weld is a circumferential pipe weld that completes assembly of the canister body and lid assembly. The second and final closure weld connects the vent plug to the vent port with an identical butt joint to the circumferential pipe weld. After the second weld is performed on the vent port, these welds are helium leak tested using an inside-out technique. In addition to the commercially available vacuum and leak detector systems, the DOE Standard Canister Closure Leak Test Assembly was designed for both remote and manual operation. This report describes fabrication and performance testing associated with the inside-out technique. INL staff designed and tested systems to accomplish these tasks. Hardware fabrication occurred at INL facilities. Forthcoming work includes design optimization, integration to existing systems, and implementation to packaging demonstration operations.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Machine learning surrogates for surface complexation model of uranium sorption to oxides

Abstract The safety assessments of the geological storage of spent nuclear fuel require understanding the underground radionuclide mobility in case of a leakage from multi-barrier canisters. Uranium, the most common radionuclide in non-reprocessed spent nuclear fuels, is immobile in reduced form (U(IV) and highly mobile in an oxidized state (U(VI)). The latter form is considered one of the most dangerous environmental threats in the safety assessments of spent nuclear fuel repositories. The sorption of uranium to mineral surfaces surrounding the repository limits their mobility. We quantify uranium sorption using surface complexation models (SCMs). Unfortunately, numerical SCM solvers often encounter convergence problems due to the complex nature of convoluted equations and correlations between model parameters. This study explored two machine learning surrogates for the 2-pK Triple Layer Model of uranium retention by oxide surfaces if released as U(IV) in the oxidizing conditions: random forest regressor and deep neural networks. Our surrogate models, particularly DNN, accurately reproduce SCM model predictions at a fraction of the computational cost without any convergence issues. The safety assessment of spent fuel repositories, specifically the migration of leaked radioactive waste, will benefit from having ultrafast AI/ML surrogates for the computationally expensive sorption models that can be easily incorporated into larger-scale contaminant migration models. One such model is presented here.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Progress Report on Model Development for Aerosol Transport through Divergent Cracks Paths

This report summarizes the progress in developing a phenomenological model of aerosol transport, deposition, and plugging through microchannels. The purpose of this effort is to introduce to a user community—involving researchers, regulators, and industry—a generic, reliable numerical model for the prediction of aerosol transport while accounting for potential deposition and plugging of the leak paths to model spent nuclear fuel (SNF) release from postulated Stress Corrosion Cracks in canisters under storage or transportation. Current work focuses on expanding the model to predict aerosol (and gas) flow through complex microchannel (nozzle) geometries in addition to the rectangular and cylindrical geometries, as we approach more realistic Stress Corrosion Crack conditions. In this regard, a divergent nozzle geometry, used at Sandia National Laboratories (SNL) for testing aerosol release and retention (Durbin et al. 2021), was added to the model. The model was then validated with blowdown data for the particular microchannel, from experiments conducted at SNL. The report also presents preliminary non-benchmarked aerosol penetration fraction and mass flow rate for a monodisperse 10-micron (AED) particle concentration of 1.7e-08 kg/m 3 being released through the divergent microchannel geometry from the SNL’s aerosol experimental tank setup.Future work will involve validating the aerosol model and updating the model’s Graphical User Interface (GUI) to include the divergent nozzle geometry. This is expected to help stakeholders perform quick and easy first principles calculations without needing to understand the underlying MATLAB script.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

Reducing Methane Emissions with an Engine Fuel Reformer

Southwest Research Institute (SwRI) designed and demonstrated a compact, plasma-based fuel reformer designed to reduce methane leaks from natural-gas engines used in pipeline compression and industrial power applications. The system uses pulsed electrical discharges to convert a small portion of methane (CH4) into hydrogen (H2) and light hydrocarbons, promoting more complete combustion and reducing unburned methane in the exhaust. The reformer was evaluated through bench-scale testing, high-flow facility testing, and engine-integration testing on representative low-speed and high-speed natural-gas engines. Measured methane-leak reductions ranged from 1 to 27 percent, depending on engine type and operating condition, while reformer energy consumption remained below one percent of total engine output. Design refinements addressed thermal and electrical challenges, resulting in reliable operation with minimal impact on engine control systems. The project achieved all performance objectives within budget and schedule, produced a patentable pulsed-power system design, and established a scalable, energy-efficient pathway for mitigating methane leaks from existing natural-gas engine infrastructure.

03 NATURAL GAS↗
NASA NTRS1966

Special tooling for joining tubing in place

The Saturn S-II stage and the Apollo spacecraft will include in their design and construction various pressurized tubing systems that will encounter service temperatures of 280° F to -423° F. Design engineering and reliability requirements and weight restrict ions have dictated new concepts to assure leak-tight joints for rocket engine fuel lines, pressurization systems, utility systems, and hydraulic systems. An investigation was initiated at North American Aviation, Inc., Space and Information Systems Division, utilizing the in-place automatically controlled miniaturized fusion-welding equipment originally developed by the Los Angeles Division of NAA and modified to meet the needs of Apollo and Saturn welded tubular systems. The objective was to make circumferential flanged weld joints in any position in 304L stainless for Saturn S-II and sleeve-type joints in 304L for Apollo. Inconel X, commercially pure titanium, 5052-0 aluminum, and 6061 T6 aluminum were also tested experimentally. Extensive environmental, static, and dynamic testing programs were conducted to determine the as-welded mechanical properties, design allowables, and reliability for the tube joints. This paper discusses both the experimental and production phases. Subsequently, the new tube welding process was approved and incorporated into manufacturing fabrication methods for tube joining.

Saturn S-II stage↗
DOE OSTI2025

Hydrogen Plus Other Alternative Fuels Risk Assessment Models (HyRAM+) Technical Reference Manual (V.6.0)

The HyRAM+ software is an open-source toolkit that provides publicly available models and default input values to enable straightforward and consistent safety assessments for hydrogen and other alternative fuel systems, such as natural gas and propane. The HyRAM+ quantitative risk assessment calculation incorporates annual likelihood of leaks or failures for both compressed gaseous and liquefied flammable fuels, as well as probabilistic models for the effects of heat flux and overpressure. HyRAM

08 HYDROGEN↗
NASA NTRS2011

Feasibility of Orion Crew Module Entry on Half of Available Propellant Due to Tank Isolation Fault

The fuel tank isolation as a result of leak or rupture can leave an Orion Crew Module with only half of the loaded propellant for ISS return atmospheric entry. To assess the feasibility of returning under this condition, an analysis of various entry control options with deliberate degradation of control performance was performed. The study determined that a ballistic entry without a raise burn, a steeper flight path trajectory, relaxed atmospheric pitch/yaw rate damping, and degraded touchdown control could achieve 2-sigma requirements compliance with a 2-sigma fuel usage that is less than half of the liftoff propellant loading. The results of this analysis indicate that an entry with only half the nominal propellant load is feasible following a tank isolation fault.

Moen, Marina M.↗
NASA NTRS1993

Compact Raman Spectrometers Would Detect Hydrogen

Compact Raman spectrometers developed to measure concentrations of hydrogen as low as hundreds of parts per million in air, nitrogen, or other carrier gases. Advantages include speed, dynamic range, and ease of calibration. Design concept incorporates Raman-scattering apparatus into compact instrument of hydrogen leaking into stream of gas or into gas enclosed in small space. Should hydrogen-fueled cars and trucks come into widespread use, instruments used to detect leaks from vehicles and supply equipment, to help prevent explosions. Similar spectrometers developed to detect other gases emitting characteristic Raman spectra.

Helms, William R.↗
NASA NTRS1973

Feasibility of an on-line fission-gas-leak detection system

Calculations were made to determine if a cladding failure could be detected in a 100-kW zirconium hydride reactor primary system by monitoring the highly radioactive NaK coolant for the presence of I-131. The system is to be completely sealed. A leak of 0.01 percent from a single fuel pin was postulated. The 0.364-MeV gamma of I-131 could be monitored on an almost continuous basis, while its presence could be varified by using a longer counting time for the 0.638-MeV gamma. A lithium-drifted germanium detector would eliminate radioactive corrosion product interference that could occur with a sodium iodide scintillation detector.

Lustig, P. H.↗
NASA NTRS1990

A figure-of-merit approach to extraterrestrial resource utilization

A concept is developed for interrelated optimizations in space missions that utilize extraterrestrial resources. It is shown that isolated (component) optimizations may not result in the best mission. It is shown that substantial benefits can be had through less than the best propellants, propellant combinations, propulsion hardware, and actually, some waste in the traditional sense. One ready example is the possibility of discarding hydrogen produced extraterrestrially by water splitting and using only the oxygen to burn storable fuels. The gains in refrigeration and leak-proof equipment mass (elimination) outweigh the loss in specific impulse. After a brief discussion of this concept, the synthesis of the four major components of any future space mission is developed. The four components are: orbital mechanics of the transportation; performance of the rocket motor; support systems that include power; thermal and process controls, and instruments; and in situ resource utilization plant equipment. This paper's main aim is to develop the concept of a figure-of-merit for the mission. The Mars Sample Return Mission is used to illustrate the new concept. At this time, a popular spreadsheet is used to quantitatively indicate the interdependent nature of the mission optimization. Future prospects are outlined that promise great economy through extraterrestrial resource utilization and a technique for quickly evaluating the same.

Ramohalli, K.↗
NASA NTRS2012

Analysis of the Pressure Rise in a Partially Filled Liquid Tank in Microgravity with Low Wall Heat Flux and Simultaneous Boiling and Condensation

Experiments performed with Freon 113 in the space shuttle have shown that in a pro- cess of very slow heating, high liquid superheats can be sustained for a long period in microgravity. In a closed system explosive vaporization of superheated liquid resulted in pressure spikes of varying magnitudes. In this paper, we analyze the pressure rise in a partially lled closed tank in which a large vapor bubble (i.e., ullage) is initially present, and the liquid is subjected to a low wall heat ux. The liquid layer adjacent to the wall becomes superheated until the temperature for nucleation of the bubbles (or the incipience of boiling) is achieved. In the absence of the gravity-induced convection large quantities of superheated liquid can accumulate over time near the heated surface. Once the incipience temperature is attained, explosive boiling occurs and the vapor bubbles that are produced on the heater surface tend to quickly raise the tank pressure. The liquid-vapor saturation temperature increases as well. These two e ects tend to induce condensation of the large ullage bubble that is initially present, and tends to mitigate the tank pressure rise. As a result, the tank pressure is predicted to rise sharply, attain a maximum, and subsequently decay slowly. The predicted pressure rise is compared with experimental results obtained in the microgravity environments of the space shuttle for Freon 113. The analysis is appli- cable, in general to heating of liquid in closed containers in microgravity and to cryogenic fuel tanks, in particular where small heat leaks into the tank are unavoidable.

Hasan, Mohammad M.↗
NASA NTRS2006

Diffusion Bonding of Silicon Carbide for a Micro-Electro-Mechanical Systems Lean Direct Injector

Robust approaches for joining silicon carbide (SiC) to silicon carbide sub-elements have been developed for a micro-electro-mechanical systems lean direct injector (MEMS LDI) application. The objective is to join SiC sub-elements to form a leak-free injector that has complex internal passages for the flow and mixing of fuel and air. Previous bonding technology relied upon silicate glass interlayers that were not uniform or leak free. In a newly developed joining approach, titanium foils and physically vapor deposited titanium coatings were used to form diffusion bonds between SiC materials during hot pressing. Microscopy results show the formation of well adhered diffusion bonds. Initial tests show that the bond strength is much higher than required for the component system. Benefits of the joining technology are fabrication of leak free joints with high temperature and mechanical capability.

Halbig, Michael C.↗