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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Evaluation of an Accident Tolerant Fuel Leak in the Advanced Test Reactor

Accident Tolerant Fuels (ATF), which are nuclear fuel sources designed to withstand operational irregularities and incidents, have been a topic of interest in the nuclear industry for several decades. Interest in ATF technology surged following the 2011 accident at Fukushima Daiichi in Japan. At the Advanced Test Reactor (ATR), one of Idaho National Laboratory’s (INL) four operating nuclear reactors, the ATF program is a collaborative effort between the national laboratory and various stakeholders within the nuclear industry. This program focuses on the research and development of novel fuel compositions, cladding, and component materials with enhanced accident-resistant properties. During one of ATR’s 60-day operating cycles in 2024, the reactor experienced five unplanned shutdowns. Following the fifth shutdown, radiation monitors detected an increase in radiation levels coming from the loop piping. Subsequent water samples confirmed the cause was a leak of fission products from the ATF experiment, designated as ATF-2C. The source of the leak was identified as the instrumented section of the test train. The primary discussions in this presentation are 1) the design of the ATF test train, 2) the operating parameters leading up to and following the detection of the leak, and 3) the quantification and characterization of the released fission products.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

Leak-tight crack repair for 304L stainless steel using friction surfacing

Here, friction surfacing (FS) was investigated as a method for sealing 50 μm wide thru-cracks in 3-mm-thick 304L stainless steel (304L) plate. Friction surfacing was performed using two sizes of 304L consumable rod, with diameters of 9.52 mm and 12.7 mm, on two substrate conditions (clean and oxidized). Friction surfacing was able to deposit a 600 μm thick coating and repair cracks to a depth of 100 μm - 200 μm below the original surface, when using the 12.7-mm-diameter consumable rod for both substrate conditions. Helium leak rates of 10 -10 atm-cc/s were achieved on crack repairs, designating them as leak-tight by the ANSI N14.5 standard. Optical and scanning electron microscopy were used to investigate the coating microstructure and bond interfaces. In this study, the 12.7-mm-diameter rod performed better with disruption of the oxide layer on the oxidized substrate and providing a more homogenous coating. Mechanical properties of the coated samples were evaluated by performing micro-indentation, tensile, bending, and adhesion testing. Higher hardness in the coatings was observed due to the fine equiaxed grains resulting from dynamic recrystallization. Complete consolidation of plastically deformed material on the substrate and a strong diffusion bond across the interface was observed. This was reflected in tensile and bending properties of the FS coatings being comparable to those of uncoated specimen. No delamination of the FS coating was observed during adhesion testing. The results demonstrate that friction surfacing is a viable option to seal cracks in stainless steels.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Surface Acoustic Wave Sensors for Refrigerant Leak Detection: Compact, Inexpensive, Selective and Sensitive Sensors

Pacific Northwest National Laboratory (PNNL), in collaboration with Parker and Hannifin, is developing a compact, inexpensive, and highly sensitive and selective surface acoustic wave sensor coated with fluorophillic sorbent for detecting fluorocarbon leaks from HVAC systems. Having a highly effective sorbent sensitive to fluorocarbon refrigerant vapors provides a means to develop a sensing device for leak detection. Surface acoustic wave (SAW) sensors with a gas sensing film deposited between the delay lines or on the interdigital transducer have been used to detect gas and vapor molecules in harsh environments with high sensitivity. As part of this project, PNNL screened several sorbent materials that are shown to be selective towards fluorocarbon refrigerant (R32) molecule. The identified sorbent materials were synthesized, characterized, and tested towards R32 using various spectroscopic technique. Next, the sorbent material was coated on a SAW sensor as a thin film using vapor deposition and drop coating methods. The coated thin film was further characterized and tested towards the detection of pure R32 and R32 in ambient air at room temperature to demonstrate the SAW response towards R32 in presence of other competing gases and vapors in air.

42 ENGINEERING↗
DOE OSTI2022

DOESC Closure Leak Test Assembly

This conceptual design report is for the DOESC Closure Leak Test Assembly, which satisfies a portion of the milestone "Preliminary Design Report for Remote Helium Leak Test System". This CDR is part of the Preliminary Design Report/Package.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Qmax Derivative Leak Tester v. 1.0

The Qmax Derivative Leak Tester is an automated tool developed to quantitatively verify the hermeticity of sealed parts without many of the pitfalls that accompany standard leak testing techniques. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525. SAND2021-0477 O

Poulter, GregoryA.↗
DOE OSTI2024

Solid-State Mixed-Potential Electrochemical Sensors for Natural Gas Leak Detection and Quality Control (Final Technical Report)

Mitigation of methane emissions are a critical factor to limiting the impact of the natural gas industry on global climate change. Throughout the period of 2020-2024, the University of New Mexico and its commercialization partner and subcontractor, SensorComm Technologies, Inc. (SCT), have worked together to develop a low-cost Artificial Intelligence (AI)-driven Internet of Things (IoT)-based multi-gas sensor platform for methane emissions detection. In the final year of the project, we extended this work to include hydrogen detection in support of a transition to a hydrogen economy where hydrogen could be transported through existing natural gas infrastructure. Mixed potential electrochemical sensors were first prototyped by ceramic additive manufacturing and then transitioned to conventional ceramic manufacturing tape casting and screen-printing technologies in preparation for mass production. Demonstrated limits of detection of 5 ppm of methane in natural gas and 1 ppm of hydrogen were measured. These limits of detection are among the lowest of solid-state electrochemical sensors that have been reported in the literature or available in the industry. Machine learning algorithms were developed to identify natural gas mixtures with > 98% accuracy level and quantify methane concentrations at 97% accuracy. The presence of hydrogen could also be identified, and its concentration quantified at these accuracy levels. These algorithms were optimized for running on portable computing hardware which enabled > 1 Hz processing rates. A portable packaged IoT system was integrated with the electrochemical sensor in collaboration with SCT. The package consists of readout electronics with < 1 mV resolution, sensor temperature control, and data transmission over cellular wireless and/or Wi-Fi networks. Field testing was performed in two rounds at Colorado State University’s Methane Emissions Technology Evaluation Center (CSU METEC). The first round of testing demonstrated successful measurements of methane from an underground natural gas leak of 20 standard liters per minute (SLPM), which agreed with previously published literature using more sophisticated and expensive analytical equipment. The second round of testing showed that an above ground leak of 2 SLPM of hydrogen could be detected at 32 ft. This project has resulted in six published peer reviewed journal articles, over ten presentations at professional conferences, and one full patent application filed in 2023. Future work on this project includes increased sensitivity, higher production yields, and applications in the hydrogen safety and flare emissions monitoring spaces.

03 NATURAL GAS↗
NASA NTRS1966

Capacitive system detects and locates fluid leaks

Electronic monitoring system automatically detects and locates minute leaks in seams of large fluid storage tanks and pipelines covered with thermal insulation. The system uses a capacitive tape-sensing element that is adhesively bonded over seams where fluid leaks are likely to occur.

Source record↗
NASA NTRS1966

Silver plating technique seals leaks in thin wall tubing joints

Leaks in thin wall tubing joints are sealed by cleaning and silver plating the hot gas side of the joint in the leakage area. The pressure differential across the silver during hydrostatic test and subsequent use forces the ductile silver into the leak area and seals it.

Blenderman, W. H.↗
NASA NTRS1965

Proceedings of the Conference on the Design of Leak-tight Fluid Connectors

These technical papers were prepared for presentation at the Conference on Design of Leak-tight Fluid Connectors sponsored by the Society of Automotive Engineers and NASA/George C. Marshall Space Flight Center. This conference was planned to promote the direct exchange of technical information concerning separable, semipermanent and permanent leak-tight fluid connectors for space vehicle use. A conference emphasizing design of separable connectors was previously held on March 24 and 25, 1964. The papers represent a cross section of significant topics on design, testing and instrumentation. This exchange of technical information between government agencies and private industry is certain to benefit the nation's space effort and other fields of technology. The sponsors of the conference extend their thanks to all companies and individuals who have contributed toward this meeting.

Connector↗
NASA NTRS1967

Portable detector set discloses helium leak rates

Portable helium detector measuring helium leak rates makes possible the use of the inert gas helium as a tracer. This helps solve safety and contamination problems in detecting leaks in closed fluid systems.

Anderson, G. E.↗
NASA NTRS1969

Burst diaphragm leak detector

New method replaces flowmeter approach with readily available burst diaphragm leak detector assembly mounted to all drain ports. This allows simultaneous leak detection of all flange seals under operating conditions.

Pascolla, J. A.↗
NASA NTRS1973

Leak detector-measurer

Detector locates leaks from inside pressurized cabins. Head is placed flush against area being tested. Should leak be present, most air inside detector housing will escape. Diaphragm will then flex into chamber and push electrical contact together, closing circuit and turning on warning light.

Sawyer, J. T.↗
NASA NTRS1973

Leak testing

Leak-testing methods for gas and liquid systems are described. The physical principles of molecular, liquid, and gas flow; relations of leak-testing methods and instrumentation; and tracer gases used in testing vacuum systems are discussed.

Engelhardt, R. E.↗
NASA NTRS1975

Leak detector

A detector for sensing a leaking of fluid pressures is reported. The detector is characterized by an hermetically sealed housing confining therewithin a first normalized pressure, a connector for coupling the housing in direct communication with a suspected leak established within a substantially sealed body, an electrical circuit having a first or normalized configuration and including a pair of circuit completing electrical contacts and means mounting at least one contact of said pair of contacts on a flexible wall of the housing supporting the contact for movement from a first position along a linear path to a second position in response to an altering of the pressure confined within the housing for thereby altering the configuration of the circuit.

Sawyer, J. T.↗
NASA NTRS1975

The effect of initial flaw configuration on leak critical pressure vessel design

The effect of initial flaw shape and depth on the cycles required to produce a pressure leak condition in parent and welded 2219-T87 aluminum was examined for thicknesses from 0.04 to 0.3 inch. Initial flaw aspect ratios of 0.5, 0.3, and 0.15 were examined for tests conducted at a frequency of 4 Hz at room temperature and at 300 F. A computer program developed by Forman was used to predict the cycles to leak curve as a function of initial crack aspect ratio, material thickness, and specimen type and the results compared with the experimental data. Sources of error in the crack propagation analysis and the interface with NDI capabilities are discussed.

Pettit, D. E.↗
NASA NTRS1975

Low-heat-leak current leads for intermittent use

The paper reports on the development of current leads for an orbiting superconducting magnetic spectrometer that were required to achieve a zero-current heat leak of 0.03 W with a total coolant flow rate as low as 0.011 g/sec cooling only the coldest third of the length of a lead. Analysis of heat flow phenomena in an insulated current lead in thermal contact with cryogenic gas flow is given for prediction of lead performance. A basic lead design was then tested and modified by such techniques as tapering, adding superconducting sections, and operating above the optimum current, until a lead satisfying the low-leak requirements was obtained. Operating the insulated leads at well above their optimum current for short periods at high mass flow is possible, and instability behavior is predictable.

Smoot, G. F.↗