Search NASA⌕ Search

SEARCH · Search NASA

Results for “sample sealing”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Hydrogen Transport in a Model 9979 Shipping Package with Inner Convenience Cans

Radiolytic hydrogen production and accumulation inside containment packages is a concern at any facility responsible for their packaging, storage, transportation, and/or disposal. When hydrogen gas accumulates to concentrations above the Lower Flammability Limit (LFL) which is 4% or 40,000 ppm in air, the possibility of a deflagration or explosion increases. This concern persists over the course of the package lifetime which is unlimited when disposed of by burial or in permanent repositories. Here, we report on a numerical model used to predict the concentration of hydrogen within each layer of a Model 9979 package containing a convenience can assembly. Simulations show the hydrogen concentration to always be highest in the inner convenience can containing the radioactive source. When the radioactive source is within the Los Alamos National Laboratory (LANL) Packaging Limits, the hydrogen concentration is shown to remain well below the LFL at all times including packaging, storage, transportation, and disposal. A hydrogen transport model is presented for a Model 9979 package system containing a nested arrangement of convenience cans, which are tin oxide coated steel cans of various sizes with a slip-lid assembly. The inner convenience can contains the radioactive source material along with an unknown quantity of incidental water acquired from humid air or processing. While visible organic materials such as paper and plastics were purposely excluded from the inner can, it is not possible to claim the wastes are entirely organic free. The inner convenience can is tape sealed and placed into a plastic bag which is horsetail closed (i.e., twisted and taped). The bagged can is placed into an outer convenience can that is also tape sealed. The can assembly is then placed into the 30 gallon drum and subsequently placed inside the 55 gallon drum in the 9979 package. Here we assume hydrogen gas is produced in the inner convenience can from alpha radiolysis of water at a rate dependent on the quantity of uranium isotopes and water present. The hydrogen transport model was used to calculate hydrogen accumulations within the package’s five layers at different times and conditions. These simulations serve two purposes; (i) to build confidence in the model by comparing predicted values to measured values, and (ii) to check the steady state hydrogen concentrations that are approached at long times in the package’s lifetime. Model simulations were compared to gas samples taken from the 30 gallon drum after storage at LANL’s Chemistry and Metallurgy Research (CMR) building for around 500 days. Hydrogen concentration calculations over much longer periods (i.e., more than 270 years) included extreme storage durations, transportation at extreme cold temperatures, and disposal of packages assuming different average temperatures.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2002

Characterization of the Protein Crystal Growth Apparatus for Microgravity Aboard the Space Station

We have conducted experiments to determine the equilibration rates of some major precipitants used in protein crystallography aboard the International Space Station (ISS). The solutions were placed in the Protein Crystallization Apparatus for Microgravity (PCAM) which mimic Cryschem sitting drop trays. The trays were placed in cylinders. These cylinders were placed inside a Single locker Thermal Enclosure System (STES), and were activated for different durations during the flight. Bumpers pressed against elastomers seal drops in a deactivated state during pre-flight and prior to transfer to the ISS. Activation occurs while in flight on the ISS by releasing the bumpers allowing the drops to be exposed to the reservoir. PCAM was flown to the ISS on STS 100, Flight 6A, on April 19, 2001. Six series of equilibration experiments were tested for each precipitant with a small amount of Green Fluorescent Protein (GFP). Cylinder 10 was never activated, 7 was activated for 40 days, 8 was activated for 20 days, 9 was activated for 10 days, 11 was activated for 4 days and 12 was activated for 2 days. Upon the return to Earth by STS 104 on July 24,2001 the samples were transferred to Marshall Space Flight Center. The samples were then brought to the lab and the volumes of each sample were measured.

Kundrot, Craig E.↗
NASA NTRS2009

Further Analysis of MISSE Polymeric Materials at MSFC

Many different spacecraft materials were flown as part of the Materials on International Space Station Experiment (MISSE). MISSE was exposed to the low Earth orbital environment of atomic oxygen, ultraviolet radiation, thermal cycling, and hard vacuum. A number of polymer samples did not survive the atomic oxygen attack. Mass and thickness loss measurements indicate the durability of the remaining polymeric materials to withstand the space environment. Results from the one-year exposure on MISSE-3 and MISSE-4 are compared to those from the four-year exposure on MISSE-1 and MISSE-2. Solar absorptance and infrared emittance measurements are given for thermal control materials. Transmission measurements are given where appropriate. A wide variety of polymeric materials were flown on MISSE, ranging from extremely thin films for solar sails to bulk materials. Some of the candidate solar sail materials were flown underneath magnesium fluoride windows to eliminate atomic oxygen effects and allow the study of ultraviolet radiation damage. Exposed seal materials include Viton , silicone, and fluorosilicone. Multi-layer insulation materials were flown, including atomic oxygen-resistant polymers. Also flown were candidate inflatable materials for a High Altitude Airship or inflatable lunar habitat. Polymer materials being flown on MISSE-6 are discussed.

Finckenor, Miria M.↗
NASA NTRS1989

Flight motor set 360T004 (STS-30R). Volume 1: System overview

The fourth NASA space shuttle flight incorporating redesigned solid rocket motors began on 4 May 1989. The flight motors were designated 360Q004A (left-hand) and 360H004B (right-hand); the mission was designated STS-30R. Overall engine performance was excellent. The low sample rate data that was available showed exceptional propulsion performance. All ballistic and mass property parameters closely matched the predicted values and were well within the required contract end item specification levels that could be assessed. No strain, vibration, or aft skirt heating environments could be addressed due to developmental flight instrumentation deletion. Infrared readings from the shuttle thermal imager were considered very good when compared with ground environment instrumentation readings taken during both the aborted and the actual countdowns. However, hand-held infrared gun reading/ground environment instrumentation comparisons were considered poor during both countdowns, with the exception of the T - 3 hour timeframe during the actual launch. Postflight inspection again verified superior performance of the insulation, phenolics, metal parts, and seals. All combustion gas was contained by the insulation in the field and case-to-nozzle joints. Inadequate parachute performance on the left-hand booster caused high splashdown loads, which resulted in a displaced nozzle and factory joint weatherseal unbond anomalies. Recommendations were made concerning improved thermal modeling and instruments. The rationale for these recommendations, the dispositions of all anomalies, and complete result details are given.

Ricks, Glenn A.↗
NASA NTRS2010

Three-Body Abrasion Testing Using Lunar Dust Simulants to Evaluate Surface System Materials

Numerous unexpected operational issues relating to the abrasive nature of lunar dust, such as scratched visors and spacesuit pressure seal leaks, were encountered during the Apollo missions. To avoid reoccurrence of these unexpected detrimental equipment problems on future missions to the Moon, a series of two- and three-body abrasion tests were developed and conducted in order to begin rigorously characterizing the effect of lunar dust abrasiveness on candidate surface system materials. Two-body scratch tests were initially performed to examine fundamental interactions of a single particle on a flat surface. These simple and robust tests were used to establish standardized measurement techniques for quantifying controlled volumetric wear. Subsequent efforts described in the paper involved three-body abrasion testing designed to be more representative of actual lunar interactions. For these tests, a new tribotester was developed to expose samples to a variety of industrial abrasives and lunar simulants. The work discussed in this paper describes the three-body hardware setup consisting of a rotating rubber wheel that applies a load on a specimen as a loose abrasive is fed into the system. The test methodology is based on ASTM International (ASTM) B611, except it does not mix water with the abrasive. All tests were run under identical conditions. Abraded material specimens included poly(methyl methacrylate) (PMMA), hardened 1045 steel, 6061-T6 aluminum (Al) and 1018 steel. Abrasives included lunar mare simulant JSC- 1A-F (nominal size distribution), sieved JSC-1A-F (<25 m particle diameter), lunar highland simulant NU-LHT-2M, alumina (average diameter of 50 m used per ASTM G76), and silica (50/70 mesh used per ASTM G65). The measured mass loss from each specimen was converted using standard densities to determine total wear volume in cm3. Abrasion was dominated by the alumina and the simulants were only similar to the silica (i.e., sand) on the softer materials of aluminum and PMMA. The nominal JSC- 1A-F consistently showed more abrasion wear than the sieved version of the simulant. The lunar dust displayed abrasivity to all of the test materials, which are likely to be used in lunar landing equipment. Based on this test experience and pilot results obtained, recommendations are made for systematic abrasion testing of candidate materials intended for use in lunar exploration systems and in other environments with similar dust challenges.

Kobrick, Ryan L.↗
NASA NTRSDate not supplied

Performance of the Dragonfly Mass Spectrometer (DraMS) Programmable UV Laser Source Engineering Test Unit (ETU)

NASA’s Dragonfly mission will sample surface materials from multiple sites on Saturn’s largest moon, Titan, in exploration of its potential for prebiotic chemistry. We report on the performance of our short-pulsed UV laser transmitter, developed for the Dragonfly’s on-board Mass Spectrometer (DraMS). Our engineering test unit (ETU) has completed flight qualification and demonstrated its operational science requirements, such that the final flight unit build can begin. The Titan Hydrocarbon Analysis Nanosecond Optical Source (THANOS) ETU laser produces 266 nm laser pulses at programmable energy levels in order to create high resolution laser desorption mass spectrometry (LDMS) measurements. The laser operates in short bursts of 1-50 pulses, each at < 2 ns pulse width, at a 100 Hz repetition rate. Creating a sealed Titanium unit, capable of operation on the extreme environment of Titan’s surface was a major engineering challenge. The laser successfully demonstrated its ability to meet all operational requirements in terms of pulse energy, beam pointing on target and repeatability even after extensive environmental testing.

Matthew W Mullin↗
NASA NTRSDate not supplied

Performance of the Dragonfly Mass Spectrometer (DraMS) Programmable UV Laser Source Engineering Test Unit (ETU)

NASA’s Dragonfly mission will sample surface materials from multiple sites on Saturn’s largest moon, Titan, in exploration of its potential for prebiotic chemistry. We report on the performance of our short-pulsed UV laser transmitter, developed for the Dragonfly’s on-board Mass Spectrometer (DraMS). Our engineering test unit (ETU) has completed flight qualification and demonstrated its operational science requirements, such that the final flight unit build can begin. The Titan Hydrocarbon Analysis Nanosecond Optical Source (THANOS) ETU laser produces 266 nm laser pulses at programmable energy levels in order to create high resolution laser desorption mass spectrometry (LDMS) measurements. The laser operates in short bursts of 1-50 pulses, each at < 2 ns pulse width, at a 100 Hz repetition rate. Creating a sealed Titanium unit, capable of operation on the extreme environment of Titan’s surface was a major engineering challenge. The laser successfully demonstrated its ability to meet all operational requirements in terms of pulse energy, beam pointing on target and repeatability even after extensive environmental testing.

Matthew Mullin↗
DOE OSTI2020

Feasibility of Realizing a Universal Identifier Based on Fiber Bragg Grating Technology

Over the past year we have collected data on different fiber Bragg gratings (FBG) with the end goal of understanding their suitability for use in a new type of unique identifier (UID) that could be used in both tags and seals for high-value, high-risk assets. The ideal UID will have a complex signature that allows items to be uniquely identified by that signature. Tamper indication must be an integral part of the tag/seal process with measurable changes to the device signature indicative of any attempt to tamper with the monitored item. Further, the signature must be so difficult to reproduce that even state-actors with significant resources at their disposal will be discouraged from attempting it. Finally, readout verification of the product must be simple and secure, while providing red-light/green-light results in real time. To evaluate how well an FBG-based UID could meet these goals, we collected data on a large number of FBG samples from different vendors. Measurements included the response of the devices to uniform tension, tension when wrapped on a mandrel, and the response to changes in temperature and humidity, as well as the effect of simple potting in expanding and nonexpanding potting materials. We tested FBG samples written into single-mode fibers that were coated with the two commonly used materials, polyimide and acrylate and gratings that were both uniform and those with an apodized response (i.e., the intensity of the grating was varied to minimize sidelobes). The result of the work to date did not find any significant issues with the design concept for a UID based on this technology. Specific findings include a baseline design comprising five FBGs with distinct spectral returns analyzed using a difference-correlation approach. To realize this device, careful attention must be given to the impact of environmental factors on the UID response, limiting the properties of the potting compounds and FBG coating materials that can be used.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

SPRUCE Diurnal and Seasonal Patterns of Water Potential in S1 Bog and SPRUCE Experimental Plot Vegetation beginning in 2010

This data set reports on water potential from excised terminal shoots or leaves (Mainthemum only) of vegetation at the SPRUCE site located in the S1 bog. Pretreatment measurements were collected from outside plots within the S1 bog. Post treatments were collected from inside SPRUCE plots. Water potential was measured on the overstory canopy species, consisting of the evergreen Picea mariana (Mill.) B.S.P. (black spruce) and deciduous Larix laricina (Du Roi) K. Koch (tamarack) trees, and ericaceous shrubs < 1 m tall, consisting of the evergreen Rhododendron groenlandicum (Oeder) Kron & Judd (Labrador tea) and Chamaedaphne calyculata (L.) Moench. (leatherleaf). Some measurement campaigns also included the evergreen Kalmia polifolia, Wangenh. (bog laurel), the deciduous Vaccinium angustifolium (Aiton) (blueberry), and the herbaceous Maianthemum trifolium (L.) Sloboda (three-leaf false Solomon’s seal). This dataset contains one data file in comma-separated (*.csv) format. This is the second release of water potential data from the site with additional data from 2018 and 2019. These data cover 2010-06-22 to 2019-07-16. Further results will be added to this data set and released to the public periodically as quality assurance and publication of results are accomplished. There are 10 experimental plots in SPRUCE: five temperature treatments (+0, +2.25, +4.5, +6.75, +9°C) at ambient CO2, and the same five temperature treatments at elevated CO2 (+500 ppm). These data span the pre- and post-treatment periods when enclosed plots were exposed to warming and elevated carbon dioxide (CO2) within the SPRUCE experiment. The pretreatment samples were collected from south end of the S1 bog prior to SPRUCE boardwalk construction, then throughout the bog once the boardwalks were completed.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1990

Flight motor set 360L007 (STS-33R)

Flight motor set 360L007 was launched as part of NASA space shuttle mission STS-33R. As with all previous redesigned solid rocket motor launches, overall motor performance was excellent. There were no debris concerns for either motor. Both motors exhibited unbonds on one factory joint weatherseal. All ballistics contract end item specification parameters were verified, with the exception of ignition interval and rise rates. Ignition interval and rise rates could not be verified due to the elimination of developmental flight instrumentation from fourth flight and subsequent, but the low sample rate data that were available showed nominal propulsion performance. All ballistic and mass property parameters closely matched the predicted values and were well within the required contract end item specification levels that could be assessed. All 108 Ground Environment Instrumentation (GEI) measurements performed properly throughout the prelaunch phase. Evaluation of the GEI measurements again verified thermal model analysis data and showed agreement with predicted environmental effects. No launch commit criteria thermal violations occurred. All joint heaters operated normally, but a high voltage reading was noted on the left hand aft heater, which was immediately determined to be a voltage sensor error and not a heater anomaly due to no current increase. Postflight inspection again verified superior performance of the insulation, phenolics, metal parts, and seals. Postflight evaluation indicated both nozzles performed as expected during flight. All combustion gas was contained by insulation in the field and case-to-nozzle joints.

Garecht, Diane↗
NASA NTRS2019

Lunar Glovebox Balance with Wireless Technology

The most important equipment required for processing lunar samples is a high-quality mass balance for maintaining accurate weight inventory, security, and scientific study. After careful review, a Curation Office memo by Michael Duke in 1978 chose the Mettler PL200 to be used for sample weight measurements inside the gloveboxes (Fig. 3). These commercial off-the-shelf (COTS) balances did not meet the strict accepted material requirements in the Lunar lab. As a result, each balance housing, weighing pan, and wiring was custom retrofitted to meet Lunar Operating Procedure (LOP) 54 requirements [for material construction restrictions]. The original design drawings for the custom housings, readout support stands, and wiring were done by the JSC engineering directorate. The 1977- 1978 schematics, drawings, and files are now housed in the curation Data Center. Per the design specifications, the housing was fabricated from aluminum grade 6061 T6, seamless welds, and anodized per MIL-A-8625 type I, class I. The balance feet were TFE Teflon and any required joints were sealed with Viton A gaskets. The readout display and support stands outside the glovebox were fabricated from 300 series stainless steel with #4 finish and mounted to the glovebox with welded bolts. Wire harnesses that linked the balance with the outside display and power were encapsulated with TFE Teflon and transported through custom Deutsch wire bulk head pass-through systems from inside to outside the glovebox. These Deutsch connectors were custom fabricated with 316L stainless steel bodies, Viton A O-rings, aluminum 6061 with electroless nickel plating, Teflon (replacing the silicone), and gold crimp connectors (no soldering). Many of the Deutsch connectors may have been used in the Apollo program high vacuum complex in building 37 and date to about 1968 to 1970.

Zeigler, Ryan A.↗
DOE OSTI2026

Synthesis of Lanthanide-Based Intermetallic Silicides

Lanthanide-containing materials are of interest because of their useful magnetic and electronic behavior. To study this intrinsic behavior, researchers need high-quality single crystals to avoid interference from grain boundaries or defects commonly found in polycrystalline samples. One method for growing single crystals is metal-flux synthesis, an approach that promotes crystal growth at lower reaction temperatures thus providing access to complex intermetallic phases. My project focuses on synthesizing novel lanthanide-containing intermetallic silicides related to previously reported f-element compounds with the Gd1??Fe4Si10?? structure type. I investigated reactions targeting lanthanum, praseodymium, neodymium, samarium, europium, and gadolinium-containing products, and used scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) to identify promising lanthanide-containing phases. I prepared reactions by loading lanthanide oxides, Co, Si, Al, and Ga into alumina crucibles in a 0.2:1:1:10:10 Ln2O3/Co/Si/Al/Ga mmol ratio, where Ln = La, Nd, Pr, Sm, Eu, or Gd. The reactions were sealed in quartz tubes, heated in a furnace, and centrifuged to separate crystals from excess flux. Afterwards, I mechanically isolated single crystals and prepared them for characterization. Pr-, Nd-, and Sm-containing reactions were confirmed through SEM-EDS to have formed the targeted quaternary phase. Single crystal X-ray diffraction (SC-XRD) data showed the Nd-containing crystals exhibited a hexagonal unit cell associated with the Gd1??Fe4Si10?? structure type. La- and Eu-containing reactions instead formed competing Co(Al/Ga/Si)3 phase crystals. Single-crystal XRD, powder XRD, and magnetic susceptibility and heat-capacity measurements will be collected for the remaining lanthanide-containing crystals. This data will help determine the complete crystal structure of the lanthanide analogues, their phase purity and whether they exhibit localized magnetic behavior, magnetic ordering, or other electronic signatures that can be compared with the previously reported actinide analogues. The disordered structure of this intermetallic family is associated with unusual magnetic and electronic behavior meaning lanthanide analogues may show potential as thermoelectric materials. Developing new thermoelectric candidate materials is relevant to energy efficiency and waste-heat recovery, which supports DOE’s broader goal of advancing science and technology solutions for America’s energy needs.

37 - INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL C↗
DOE OSTI2026

Observations of marine animal interactions with a small tidal turbine

The risk of collisions between animals and operating tidal turbines remains a concern in the scientific and regulatory communities. A sensor package including optical cameras was deployed to monitor animal interactions with a small-scale (1 m 2 ) cross-flow tidal turbine. The turbine was deployed in Washington State, USA for 141 days at a site with peak flow speeds of 2.5 m/s. We analyze optical camera imagery spanning 109 days of turbine operation. The analyzed images contain 1044 observations of fish, fish schools, seabirds, or seals in the vicinity of the turbine. No instances of collision with seabirds or seals were observed. Seabirds were only observed during daylight hours and while the turbine was stationary. Both seals and fish were observed during both day and night and while the turbine was stationary and rotating. Four fish were observed colliding with the moving turbine and in all but one case the animals swam away following the collision. Over the same period of time, over fifty times more fish (224 individual fish and 5 fish schools) were observed passing the moving turbine without collision. Fish encounters were likely under counted due to the difficulty in discerning small fish from plant matter in the water column. These observations represent the first optical camera imagery showing fish, bird, and marine mammal interactions with a tidal turbine in North America. In addition to quantitative and qualitative discussion of the implications of our observations for collision risk, we discuss lessons learned on sampling schemes and deployment of machine learning for detection of animals to inform future data collection strategies in future monitoring campaigns.

16 TIDAL AND WAVE POWER↗
DOE OSTI2024

STUDIES ON PIPELINE POLYETHYLENES IN HYDROGEN GAS ENVIRONMENTS USING IN-SITU AND EX-SITU CHARACTERIZATION METHODS

Polymeric materials are commonplace in the natural gas infrastructure as distribution pipes, coatings, seals, and gaskets. Under the auspices of the U.S. Department of Energy HyBlend program, one of the means to reduce greenhouse gas emissions is with replacing natural gas, either partially or completely, with hydrogen. This approach makes it imperative that we conduct near-term and long-term materials compatibility research in these relevant environments. Insights into the effects of hydrogen and hydrogen gas blends on polymer integrity can be gained through both ex-situ and in-situ analytical methods. Our work represented here highlights a study of the behavior of pipeline polyethylene (PE) materials, including HDPE (Dow 2490 and GDB50) and MDPE (Ineos and legacy Dupont Aldyl A), when exposed to hydrogen by means of in-situ X-ray scattering and ex-situ Raman spectroscopy techniques. Samples were tested in ex-situ hydrogen and argon gas environments and in-situ hydrogen environments to identify differences due to permeation and solubility of these gases. These methods complemented each other because Raman spectroscopy could capture permanent effects after materials were removed from gaseous environments, and in-situ X-ray scattering analysis collected real-time data to elucidate the impact of the gas environment on polymer microstructure. Data collected revealed that the aforementioned polymers did not show significant changes in crystallinity and microstructure under the exposure conditions tested. Our findings from these studies will help establish real-time effects caused by hydrogen gas transport through pipeline polyethylenes by way of its influence on polymer structure and chemistry, which is directly related to pipeline mechanical strength and longevity of service.

Hydrogen materials compatibility, Natural gas pipe↗
DOE OSTI2022

Extended Modeling of DOE Sealed Canisters with Updated Chemistry Models

Road-ready and final disposition packaging configurations for the advanced test reactor (ATR) fuel currently specifies storage within helium backfilled DOE sealed standard canisters. The aluminum cladding of the ATR fuel contains an oxyhydroxide layer of boehmite/bayerite that generates hydrogen when subjected to irradiation. Understanding the effect of this hydrogen buildup over time to important for long term storage considerations. Previous modeling efforts have built a coupled CFD-chemical model to simulate the temperature gas phase concentrations within the DOE sealed standard canisters. These models have coupled the temperature conditions to both the gas phase radiolysis chemistry and the surface chemistry associated with the oxyhydroxide layer. The previous iteration of the model utilized constant G-values for the hydrogen generation a 50-year period. This new iteration of the model utilizes new experimental data to update the hydrogen generation rate, as well as increase the simulated time to a 200-year period. Given the half-life assumed for the primary Cs-137 isotope responsible for gamma radiation in the ATR spent fuel, the 200-year period decreases the decay heat and dose rate of the spent fuel by a factor of 100, which combined with the updated chemistry substantially decreases new hydrogen generation. Continued experimental work has identified trends for aluminum surrogate samples with oxyhydroxide layers for tests done at higher dose rates. At low initial doses a fast generation rate of hydrogen occurs which starts to roll over to a lower generation as the total dose applied increase. A small-scale chemical model was built to replicate as mini-canister surrogate system at SRNL as well as for the smaller capsule tests performed at INL. A variety of chemical models to capture this effect were tested, and a back reaction of H radical absorbing onto the surface, or inhibition of the reaction by significant H 2 cover gas were both able to fit both the mini-canister and the small capsule test data. Both kinetic fits were used to generate data from the new 200-year simulation. As additional experiments continue, the kinetic fits may be adjusted to adapt to new data. However, updated data shows that hydrogen atmosphere has little effect on actual generation data, so the model was reverted to use a star-stepped G-value for low-dose and high-dose regions. For the undried fuel case, the three models differ significantly with an end concentration of 1% for back reaction, 4.2% for inhibition, and 13.1% for constant G-value for the nominal scenario. For the dried fuel case, the nominal cases showed end concentrations of 0.23% for back reaction, 1.9% for inhibition, and 4.2% for const G-value for the nominal scenario. For the constant G-value case that is less conservative than the other two, the pressure for undried fuel increases to 1.94 atm over 200 years for the nominal case and 2.11 atm for the high decay heat case. The total hydrogen concentration after 200 years is 4.92% for the low decay heat case and 27.4% for the high decay heat case for undried fuel and is 1.4% and 9.6% for low and high decay heat fuel for the dried fuel case. If small amount of residual air is present, the potential for nitric acid formation of 595, 1568, and 2816 ppm for the lower, nominal, and upper fuel decay heat can occur. At long-term timeframes no significant shift in major species present occurs, so no appreciable amount of oxygen is present in the system. The continued rate of hydrogen generation in the canister occurs at an increase of 0.04% by mole over the final 10 years. Increasing the model range out to 1000 years continues to drop the hydrogen generation rate through decreasing dose rate.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

High Pressure and Two-Sided Mold Surface Solutions (CRADA Final Report)

This project provided surface solutions for highly loaded precision tooling relevant to the automotive industry. Previous development work in coatings for Big Area Additive Manufacturing (BAAM) has produced commercialized coatings for low temperature Acrylonitrile Butadiene Styrene (ABS) tools (TD Coat RT) as well as a soft coating for high temperature applications (TD Seal HT). The team developed these coatings and commercialized them during a prior Manufacturing Demonstration Facility (MDF) technical collaboration (NFE-15-05793). During the prior collaboration, commercialization testing was successfully performed by the Boeing and NAVAIR and resulted in an Awards for Composites Excellence (ACE), award at CAMX – The Composites and Advanced Materials Expo 2016. While this work was clearly successful, gaps in the technology were identified, that prevent widespread adoption of large-scale additive manufacturing in high pressure tooling applications prevalent in the automotive industry. In this project we focused on development of surface solutions for two-sided, compression molding tooling printed on a large-scale polymer AM system in an arbitrary build orientation. We have printed a single cavity extrusion compression molding mold using Polyphenylene sulfide/carbon fiber (PPS/CF) materials, 50% by weight CF samples. These processes are commonly used by Original Equipment Manufacturers (OEM) and Tier 1 suppliers for high volume automotive applications. Several OEMs have identified the need for such technology, indicating significant time and monetary savings could be possible if commercially available surface solutions for high pressure Additive Manufacturing (AM) tooling existed.

36 MATERIALS SCIENCE↗
NASA NTRSDate not supplied

Ariane 5 Fairing Preparations for James JWST Space Telescope

The James Webb Space Telescope (JWST) is a large, infrared space telescope operating at Lagrange point 2. JWST is a joint effort between NASA, ESA, and CSA and was launched from the Centre Spatial Guyanais (CSG) on an Ariane 5 rocket in December 2021. The Ariane 5 payload faring (PLF), as shown in Figure 1, interior and Vehicle Equipment Bay membranes received multiple cleanings, detailed inspections, and verification sampling to achieve necessary cleanliness levels. Investigation of PLF cleanliness began early in the JWST program to test the Fairing Acoustic Protection (FAP) panels. Initial PLF cleaning was performed at RUAG in Switzerland prior to shipment to the launch site in collaboration with NASA and ESA. The cleaning procedure used at RUAG premises was based on heritage of the PLF cleaning procedure for ESA/Herschel-Planck and NASA/Mars2020 missions on an Atlas V launcher. The Ariane 5 fairing was packaged in a clean manner and inspected and cleaned upon arrival to CSG. Silicon wafers and particle fall out (PFO) plates were used to monitor the internal fairing cleanliness prior to encapsulation. Just after encapsulation, PFO plates and calcium fluoride (CaF2) crystals were placed inside the fairing on a specific tool door for monitoring the cleanliness inside the fairing during the ventilation phase. The fairing itself was specially sealed to protect the inner environment with just a small, doored porthole accessible via diving board for final closeout of the purge interface. Fairing cleanliness was achieved and mitigated contamination distribution upon launch.

James Webb Space Telescope↗
NASA NTRS2007

A Rapid Survey of the Compatibility of Selected Seal Materials with Conventional and Semi-Synthetic JP-8

Since the synthesis of a liquid hydrocarbon fuel from coal by Franz Fischer and Hans Tropsch in 1923, there has been cyclic interest in developing this fuel for military and commercial applications. In recent years the U.S. Department of Defense has taken interest in producing a unified battlespace fuel using the Fischer Tropsch (FT) process for a variety of reasons including cost, quality, and logistics. In the past year there has been a particular emphasis on moving quickly to demonstrate that an FT fuel can be used in the form of a blend with conventional petroleum-derived jet fuel. The initial objective is to employ this semi-synthetic fuel with blend ratios as high as 50 percent FT with longer range goals to use even high blend ratios and ultimately a fully synthetic jet fuel. A significant concern associated with the use of a semi-synthetic jet fuel with high FT blend ratios is the effect these low aromatic fuels will have on fuel-wetted polymeric materials, most notably seals and sealants. These materials typically swell and soften to some degree when exposed to jet fuel and the aromatic content of these fuels contribute to this effect. Semi-synthetic jet fuels with very low aromatic contents may cause seals and sealants to shrink and harden leading to acute or chronic failure. Unfortunately, most of the material qualification tests are more concerned with excessive swelling than shrinkage and there is little guidance offered as to an acceptable level of shrinkage or other changes in physical properties related to low aromatic content. Given the pressing need for guidance data, a program was developed to rapidly survey the volume swell of selected fuel-wetted materials in a range of conventional and semi-synthetic jet fuels and through a statistical analysis to make a determination as to whether there was a basis to be concerned about using fuels with FT blend ratios as high as 50 percent. Concurrent with this analysis data was obtained as to the composition of the fuel absorbed in fuel-wetted materials through the use of GC-MS analysis of swollen samples as well as other supporting data. In this presentation the authors will present a summary of the results of the volume swell and fuel absorbed by selected O-rings and sealants as well as a description of the measurement protocols developed for this program.

Graham, John L.↗