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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Aerospace Payloads Leak Test Methodology

Pressurized and sealed aerospace payloads can leak on orbit. When dealing with toxic or hazardous materials, requirements for fluid and gas leakage rates have to be properly established, and most importantly, reliably verified using the best Nondestructive Test (NDT) method available. Such verification can be implemented through application of various leak test methods that will be the subject of this paper, with a purpose to show what approach to payload leakage rate requirement verification is taken by the National Aeronautics and Space Administration (NASA). The scope of this paper will be mostly a detailed description of 14 leak test methods recommended.

Lvovsky, Oleg↗
NASA NTRS2020

Fitting Leak Test Report

Many Human Landing System flight elements are anticipated to implement mechanically connected joints in cryogenic fluid lines to simplify system assembly. These joints will need to survive launch vibration, while cold, and remain as leak‐free as possible to minimize commodity loss. Threaded fluid fittings should be qualified for use in their expected environments to reduce risk and ensure mission success. A new ground‐based test apparatus was developed and validated to obtain quantifiable low leak rate test data for a small component, such as a pressurized threaded fluid fitting, while in the temperature range of liquid hydrogen. A cryocooler is used to attain the cold test temperature and helium leakage from a pressurized fitting mounted within a vacuum test chamber is measured using a mass spectrometer leak detector. Two different sizes of Swagelok VCR fittings with three different types of seal rings were selected as the test articles for the initial proof of concept testing. Each fitting configuration was subjected to two consecutive cryogenic thermal cycles and cold leak measurement tests, followed by exposure to a high vibration test profile at ambient temperature on a shaker table, and then two additional cold leak measurement tests. Very low leak rates, below the acceptable leak rate threshold, were measured at the pressures tested. Several enhancements to the test hardware are discussed that would facilitate a comprehensive fitting qualification test campaign by enabling a higher test throughput rate and ensuring a repeatable test profile.

Cryogenic Fluid Management↗
NASA NTRS1972

Leak test system

System for quantitative determination of leak rates in large pressurized compartments is described. Method uses pressure reference cylinder placed in thermal contact with internal environment of compartment. Construction of equipment and details of operational procedure are reported. Illustration of equipment is included.

Morris, R. G.↗
DOE OSTI2022

Leak test for solid oxide fuel cells and solid oxide electrolysis cells

A simple, fast, and economical alcohol penetration method for assessing the solid oxide cell to metal window frame seal in a typical planar design is presented. An alcohol such as ethanol or isopropanol is placed into the cavity of a cell sealed to the window frame. Within 3–5 min, one can determine if the glass seal is hermetic by visual observation along the seal edges on the side of the sealed frame. Cross bubbling and open circuit voltage methods for determining whether the seal failed or cracked at high temperature after final stack firing are also discussed.

25 ENERGY STORAGE↗
DOE OSTI2024

He Leak Testing of 3013 Inner Container Lids

The 3013-container package is used for the long-term storage of plutonium bearing materials at Department of Energy (DOE) sites. The package consists of three nested stainless-steel containers: outer, inner and convenience, which are made of stainless steel. The requirements of the DOE 3013 Standarda, also entail the development of a surveillance program, tasked to ensure structural integrity of the outer container for at least 50 years. The Materials Identification and Surveillance Working Group (MIS-WG) is specified to be responsible for selecting the containers for the surveillance as well as analyzing results. The MIS-WG determined that corrosion is a potential mechanism for container degradation with the most credible type of failure to be stress corrosion cracking (SCC) through wall breach of the inner container closure weld region (ICCWR). A breach of the inner container has the potential of allowing corrosive gases to be released into the safety class outer container.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1984

Leak Test for Pressure-Sealing Zippers

Test jig checks either side of pressure-sealing zippers for leaks. Procedure takes little time, and seal failure determined before zipper incorporated into suit.

Erickson, E.↗
NASA NTRSDate not supplied

Ground-Based Cryogenic Leak Test of Fittings for Cryogenic Fluid Management

Mechanically connected fluid joints are virtually unavoidable in complex cryogenic system designs. In the case of spacecraft, the performance of these joints is critical to mission success. This is especially true for long-duration space missions where even very low leak rates can eventually lead to significant propellant losses or failure of vital cryogenic cooling systems. NASA has recently undertaken an effort to quantify the leak rate of Vacuum Coupling Radiation (VCR) fittings over the temperature range from ambient to 20 K, both before and after exposure to a launch vibration profile. A test apparatus employing a cryocooler and a calibrated helium mass spectrometer was developed, validated, and used to obtain quantifiable leak rates at a fitting test pressure of 31 bar (450 psig). Three different fitting sizes were tested, 25.4 mm (¼ inch), 12.7 mm (½ inch), and 6.35 mm (1 inch) and two gasket materials, stainless steel, and silver-plated nickel. Each fitting configuration (size/seal material) was subjected to two consecutive cryogenic thermal cycles/measurement tests, followed by a launch vibration test profile at ambient temperature, and then two additional cryogenic thermal cycles/measurement tests. The design and development of the test apparatus, and test data are presented and discussed in detail.

G J Tamasy↗
NASA NTRS1974

Nondestructive leak testing

Method provides opportunity to effect repairs without compromising integrity of enclosed circuitry or mechanism by loss of atmosphere or by ingestion of foreign matter or gas. It is possible to detect leaks in modules which are sealed while fully evacuated, partially evacuated, or containing some form of gas.

Lusby, T. K., Jr.↗
DOE OSTI2021

Sealed Vessel Leak Test [Slides]

A test plan has been developed to verify the results obtained from sealed vessels used in support of the JT5-Alt370-IN-1 compatibility testing. The test plan needs to be verified by doing a mock test on testing vessels, it will be adjusted and redone as necessary then conducted on the remaining vessels from the compatibility tests.

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

Helium Leak Test Data for System Evaluation

The test data in the flowing pages below has been created to ensure the maintenance conducted on the current MSHLD systems is satisfactory per ASNT Level III review. This is diagnostic test data only and it is intended to be used as a reference document.

36 MATERIALS SCIENCE↗
NASA NTRS1967

Fixture facilitates helium leak testing of pipe welds

Fixture facilitates inspection testing of circumferential pipe welds for vacuum tightness, using helium gas as a leakage tracer in conjunction with a mass spectrometer. It consists of a split rubber torus and a mating clamping ring with a vacuum hose fitting.

Roney, J. A.↗
NASA NTRS1972

Leak decay method of helium bombardment leak testing

Method for verifying hermetic seal quality of small components is described. Procedure for using helium bombardment and examination with mass spectrometer is described. Technique eliminates errors in seal quality determination and checks quality of seals without contaminating products.

Garton, W. P.↗