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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 1,693 records · Page 94
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

ANALYSIS OF THE LEACHING EFFICIENCY OF INHIBITED WATER AND TANK SIMULANT IN REMOVING RESIDUES ON THERMOWELL PIPES

A key component for the accelerated implementation and operation of the Salt Waste Processing Facility (SWPF) is the recovery of Tank 48H. Tank 48H is a type IIIA tank with a maximum capacity of 1.3 million gallons. Video inspection of the tank showed that a film of solid material adhered to the tank internal walls and structures between 69 inch and 150 inch levels. From the video inspection, the solid film thickness was estimated to be 1mm, which corresponds to {approx}33 kg of TPB salts (as 20 wt% insoluble solids) (1). This film material is expected to be easily removed by single-rinse, slurry pump operation during Tank 48H TPB disposition via aggregation processing. A similar success was achieved for Tank 49H TPB dispositioning, with slurry pumps operating almost continuously for approximately 6 months, after which time the tank was inspected and the film was found to be removed. The major components of the Tank 49H film were soluble solids - Na{sub 3}H(CO{sub 3}){sub 2} (Hydrated Sodium Carbonate, aka: Trona), Al(OH){sub 3} (Aluminum Hydroxide, aka: Gibbsite), NaTPB (Sodium Tetraphenylborate), NaNO{sub 3} (Sodium Nitrate) and NaNO{sub 2} (Sodium Nitrite) (2). Although the Tank 48H film is expected to be primarily soluble solids, it may not behave the same as the Tank 49H film. There is a risk that material on the internal surfaces of Tank 48H could not be easily removed. As a risk mitigation activity, the chemical composition and leachability of the Tank 48H film are being evaluated prior to initiating tank aggregation. This task investigated the dissolution characteristics of Tank 48H solid film deposits in inhibited water and DWPF recycle. To this end, SRNL received four separate 23-inch long thermowell-conductivity pipe samples which were removed from the tank 48H D2 risers in order to determine: (1) the thickness of the solid film deposit, (2) the chemical composition of the film deposits, and (3) the leaching behavior of the solid film deposit in inhibited water (IW) and in DWPF recycle simulant (3).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Forensic Determination of Residual Stresses from Fracture Surfaces

Forensic engineering - the scientific examination and analysis of failed structures and parts relating to their failure or cause of damage. Real advances in experimental mechanics require innovative theoretical and analytical thinking to go with innovative capabilities. For example, taking full field data (e.g., DIC) and treating it like discrete data (strain gauge) misses a wonderful opportunity.

36 MATERIALS SCIENCE↗
DOE OSTI2018

The DISTINCTIVE University Consortium: Theme 2: PuO{sub 2} and Fuel Residues - 18132

The safe and secure management of Pu is a matter of serious international concern, with ∼250 t of separated Pu currently stockpiled worldwide. Nearly 50% of this material is in long-term storage in the UK whilst the British government develops its options for final treatment and disposition. Options for this are: (i) reuse as a fuel in modern reactors (e.g. as MOX fuel or within a fast reactor) prior to disposal; (ii) prompt immobilisation for disposal as soon as is practicable; or, (iii) continued long term storage (prior to disposition). The focus of the work presented here is options (ii) and (iii). The R and D needs of both are now pressing: in option (iii) due to it being the current default; in option (ii) because of a comparative lack of R and D on Pu conditioning and packaging due to policy uncertainty as to whether it would be disposed of in a Geologic Disposal Facility (GDF). Addressing these needs is complicated by Pu's high radioactivity, decay heat and radiotoxicity, nuclear safeguard requirements and, for some UK Pu contaminated materials targeted for disposal, poor inventory. Thus, there is also a critical requirement for underpinning research on characterisation methods for Pu bearing materials. In response to these needs, the DISTINCTIVE Consortium (Decommissioning, Immobilisation and Storage Solutions for Nuclear Waste Inventories, a multi-disciplinary collaboration of 11 universities and 3 key industry partners from across the UK's civil nuclear sector) has been seeking to: - Understand how the structure and properties of PuO{sub 2} change with time in the presence of H{sub 2}O. - Understand the roles these processes play in gaseous product evolution from PuO{sub 2} in storage. - Understand radiation-induced amorphization and dissolution kinetics of Pu waste forms. - Develop novel, fast neutron based radiometric methods for the quantification, isotopic composition assessment and remote imaging of Pu-bearing materials. This paper describes recent progress made towards achieving these objectives. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Sustainable Graphite and Jet Fuel from Biorefinery Residue

Abstract Battery‐grade graphite and aviation fuel are traditionally produced from non‐renewable, fossil carbon feedstocks and result in substantial greenhouse gas emissions. Biomass holds exciting potential as a renewable and sustainable feedstock for the production of graphite and aviation fuel, but challenges exist including the necessity of a catalyst when producing graphite and low selectivity when producing aviation fuel. A process to convert a biomass‐derived feedstock into graphite without the use of a catalyst and fuels with high selectivity towards sustainable aviation fuel (SAF) is innovated. Heavy bio‐oil undergoes a conversion process similar to the commercial production of synthetic graphite including coking at 500 °C, calcination at 1000 °C, and graphitization at 2800 °C. The resulting biographite exhibits excellent performance in lithium‐ion battery configurations with specific capacity of ~330 mAh g −1 and a 96.8 % capacity rebound after high rate cycling. The liquid hydrocarbon co‐product from coking is suitable for hydrotreating into SAF. The aviation fuel fraction (70 wt % of the fuel produced) meets ASTM standards and is composed primarily of cycloalkanes (~80 wt %) which improves energy density compared to paraffins produced by other SAF pathways and may replace aromatics for elastomer swelling in traditional jet fuel with less soot production.

09 BIOMASS FUELS↗
DOE OSTI2018

Enhancing the Oxidation Stability of Polydivinylbenzene Films via Residual Pendant Vinyl Passivation

Polydivinylbenzene (PDVB) is a thermally stable, optically transparent, crosslinked polymer that until recently has been difficult to synthesize as a thin film. With the recent demonstration of initiated chemical vapor deposition (iCVD) of thin PDVB films, a renewed interest in the material properties of PDVB has developed. In particular, attention is now focused on its oxidation pathways and long-term stability under the desired application use conditions. In this paper, we report on the thermal and environmental stability of PDVB films and show that unreacted pendant vinyl groups drive polymer oxidation upon exposure to either air or light. We demonstrate that such vinyls can be effectively passivated by a simple ex-situ thermal annealing at ca. 300 °C in inert atmosphere that induces an 87% reduction of the PDVB oxidation rate in air and slows light (λ=405 nm) induced oxidation by 56%. While the thermal annealing is less effective at preventing oxidation under higher energy (λ = 365 nm) UV light, we demonstrate that this aging pathway is based on the presence of reactive oxygen species rather than traditional photo-oxidation. Finally, vinyl removal through ex-situ thermal annealing improves the chemical stability of iCVD PDVB to continuous air (over 500 days) or light (70 hours) exposure and offers a simple option to improve its environmental aging resistance which is important for long-term protective applications.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Residual fracture energy of natural and recycled aggregate concrete after exposure to high temperatures

Abstract Fracture energy ( G F ) represents the average total energy consumed in the whole process of crack propagation. Using one parameter of G F , it is not sufficient to describe the fracture behavior during crack stable and unstable propagation periods. In this study, the G F , stable fracture energy ( G FS ) and unstable fracture energy ( G FU ) of natural and recycled aggregate concrete (RAC) were investigated by using three‐point bending tests. Totally, 128 cubic specimens (100 mm × 100 mm × 100 mm) and 64 notched beams with size of 510 mm × 100 mm × 100 mm were manufactured to test the compressive strength ( f cu ), splitting tensile strength ( f t ), load–deflection (P‐δ), and load‐cracking mouth opening displacement (P‐CMOD) curves, considering different replacement levels (0%, 30%, 70%, and 100%) of recycled coarse aggregate (RA) and high temperatures exposure (20, 100, 200, and 300°C). The effects of RA substitutions and temperatures on basic mechanical properties, G F , G FS , and G FU were analyzed. The results demonstrated that the f cu , f t , and elastic modulus ( E ) decreased with the incremental temperature. The G FS of concrete with different RA substitutions first decreased and then increased, and the minimum value appeared at 200°C. The G F and G FU of concrete with different RA substitutions increased with the elevated temperature, and the increase rate decreased with RA substitutions. When the temperature is less than 100°C, the G F and G FU of concrete remained mostly unchanged with the increase of RA substitutions, while the temperature reached 200 and 300°C, the G F and G FU of concrete increased and decreased with the increase of RA substitutions, respectively.

Chen, Wei↗
DOE OSTI2019

Rhodococcus and Yarrowia-Based Lipid Production Using Lignin-Containing Industrial Residues

Improvement in biorefining technologies coupled with development of novel fermentation strategies and analysis will be paramount in establishing supplementary and sustainable biofuel pathways. Oleaginous microorganisms that are capable of accumulating triacylglycerides (TAGs) and fatty acid methyl esters (FAMEs), such as Rhodococcus and Yarrowia species, can be used to produce second-generation biofuels from non-food competing carbon sources. These “microbiorefineries” provide a pathway to upgrade agricultural and industrial waste streams to fungible fuels or precursors to chemicals and materials. Here we provide a general overview on cultivating Rhodococcus and Yarrowia on agro-waste/industrial biomass pretreatment waste streams to produce single-cell oils/lipids and preparing samples for FAME detection.

Le, Rosemary K.↗