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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Activation Energies of Harvested Boston Insulated Wire and Okonite Cable Materials

As part of the Cable Aging Task within the Material Aging and Degradation (MAaD) pathway of the DOE Light Water Reactor Sustainability (LWRS) program, ORNL is collaborating with Pacific Northwest National Laboratory (PNNL), the Electric Power Research Institute (EPRI), and the US Nuclear Regulatory Commission (NCR) to study cable aging mechanisms. Understanding cable aging mechanisms in cable nuclear power plants (NPPs) with needed information as they seek plant life extensions to 80 years of operations. This report summarizes activities in the characterization of harvested electrical I&C cables related to activation energy and their role in determining the remaining margin of time cable insulation in NPPs can be used. Activation energy is the amount of energy that is required to break chemical bonds in a polymer through an endothermic reaction. For I&C cables that are utilized in NPPs, activation energy is used with a time and temperature dependent cable property like elongation at break (EAB) and/or an electrical property like voltage withstand to determine whether a cable insulation material meets the performance requirements for the environmental conditions such as temperature, radiation, and humidity for a given plant location. Considering differences in activation energies that were observed in harvested cable jackets when compared to previous measurements, an assessment of the cable insulation activation energy in harvested I&C cables was performed given that the insulation performance ultimately determines that lifetime performance for a cable. This assessment consisted of the mechanical and chemical characterization of harvested Boston Insulated Wire (BIW) and Okonite cable insulations from Zion NPP from a series of thermal accelerated aging exposures between 140°C and 160°C. Cables were obtained as part of the LWRS Zion Harvesting Project in cooperation with Energy Solutions and the NRC. Activation energies of 1.10 eV and 0.61 eV were obtained for BIW and Okonite manufactured ethylene propylene rubber (EPR) insulation with individual chlorosulfonated polyethylene (CSPE) jackets respectively. When compared to previous measurements, the activation energy of BIW agreed well, while there was a sizeable gap for previous Okonite activation energies near 0.91 eV. The lack of agreement could be attributed to differences in raw materials used in a given insulation and/or jacket, differences in the thicknesses of the EPR insulation and CSPE individual jacket or the environmental conditions that the insulation from previous measurements experienced prior to characterization especially if cables were not stored at manufacturer recommended conditions. Comparison of harvested insulation compositions from multiple NPP sites and locations in a given NPP with respect to activation energy could provide some guidance on property sensitivity and insulation variations. To address the issue of material thickness, an initial assessment of the influence of the CPSE individual jacket was also done. This was motivated by the different combinations of EPR insulation and CSPE individual jacket thicknesses that were found in harvested cables and previous measurements. Accelerated thermal aging of BIW-manufactured EPR insulation with individual CSPE jackets removed did show that the CSPE layer affected insulation degradation, further comparison of the compositional make-up of the CSPE and EPR for both BIW and Okonite insulation, along with a limited amount of additional accelerated aging, is needed to increase the level of confidence regarding the influence of the CSPE.

36 MATERIALS SCIENCE↗
NASA NTRS1989

Microstructure-mechanical property relationships for Al-Cu-Li-Zr alloys with minor additions of cadmium, indium or tin

Minor amounts of cadmium, indium or tin were added to a baseline alloy with the nominal composition of Al-2.4Cu-2.4Li-0.15Zr. These elements were added in an attempt to increase the age-hardening response of the material such that high strengths could be achieved through heat-treatment alone, without the need for intermediate mechanical working. The alloy variant containing indium achieved a higher peak hardness in comparison to the other alloy variations, including the baseline material, when aged at temperatures ranging from 160 C to 190 C. Tensile tests on specimens peak-aged at 160 indicated the yield strength of the indium-bearing alloy increased by approximately 15 percent compared to that of the peak-aged baseline alloy. In addition, the yield strength obtained in the indium-bearing alloy was comparable to that reported for similar baseline material subjected to a 6 percent stretch prior to peak-aging at 190 C. The higher strength levels obtaied for the indium-bearing alloy are attributed to increased number densities and homogeneity of both the T1 and theta-prime phases, as determined by TEM studies.

Blackburn, L. B.↗
DOE OSTI2018

Next Generation Three-Way Catalysts for Future, Highly Efficient Gasoline Engines (Final Technical Report)

Ford Motor Company, Oak Ridge National Laboratory, and the University of Michigan completed a 3.25 year project on exhaust catalysts for gasoline vehicles that exhibit higher activity at lower temperatures down to 150°C. Ford has successfully used catalysts on cars and trucks to control emissions for over forty years. Changes in gasoline engine technology have allowed the use of “high tech” three-way catalysts (TWCs) to simultaneously control HC (hydrocarbons), CO (carbon monoxide), and NOx (nitrogen oxides) at nearly 100% efficiency. Excess fueling is used upon engine start to heat the catalyst up to its full operating temperature of greater than 350°C, lowering fuel economy and creating particulate matter. It was desirable to develop new catalysts for lower operating temperatures that may occur with future, more efficient gasoline powered vehicles, while still being durable to 150,000 mi with peak temperatures of 960°C. The work included laboratory preparation, aging, and poisoning of catalyst materials, activity tests, and chemical analyses. The objective of this project was to demonstrate progress toward the USDRIVE goal of achieving durable 90% conversion (T90) of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) at 150°C. The project partners focused on several supported metal catalyst structures to promote lower light-off temperatures, enhance metal-support interaction, and improve durability. The raw materials (oxides of aluminum, cerium, silicon, titanium, and zirconium) were not new, but were used in novel ways. Palladium (Pd) or rhodium (Rh) were supported either on layered metal oxide supports, on nanoparticles, or used in various core@shell configurations. Catalyst materials were aged hydrothermally to a simulated high mileage. The catalyst formulation with the lowest durable light-off was 0.5 wt% Rh supported on alumina with an overlayer of either Ti or Zr. The temperatures for 90% conversion were up to 128°C lower than those of a commercial Pd three-way catalyst that had > 3x metal loading of the new Rh catalyst. An additional material made of Pd supported on nanoparticles of ceria-zirconia (CZO) was also considered; the aged T90s were up to 40°C lower than the commercial catalyst, at similar metal loading. Further understanding of the catalyst architecture provided additional confidence to move forward with scale-up of 0.5 wt% Rh/Ti/Al2O3 to coated monolith laboratory cores for further evaluation. The team worked with Johnson Matthey to accomplish this, in addition to exploring manufacturability and potential costs. The overall benefit was estimated to be 10-15% lower NMOG and NOx tailpipe emissions on a cold start certification cycle.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Next Generation Three-Way Catalysts for Future, Highly Efficient Gasoline Engines (Final Report)

Ford Motor Company, Oak Ridge National Laboratory, and the University of Michigan completed a 3.25 year project on exhaust catalysts for gasoline vehicles that exhibit higher activity at lower temperatures down to 150°C. Ford has successfully used catalysts on cars and trucks to control emissions for over forty years. Changes in gasoline engine technology have allowed the use of “high tech” three-way catalysts (TWCs) to simultaneously control HC (hydrocarbons), CO (carbon monoxide), and NOx (nitrogen oxides) at nearly 100% efficiency. Excess fueling is used upon engine start to heat the catalyst up to its full operating temperature of greater than 350°C, lowering fuel economy and creating particulate matter. It was desirable to develop new catalysts for lower operating temperatures that may occur with future, more efficient gasoline powered vehicles, while still being durable to 150,000 mi with peak temperatures of 960°C. The work included laboratory preparation, aging, and poisoning of catalyst materials, activity tests, and chemical analyses. The objective of this project was to demonstrate progress toward the USDRIVE goal of achieving durable 90% conversion (T90) of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) at 150°C. The project partners focused on several supported metal catalyst structures to promote lower light-off temperatures, enhance metal-support interaction, and improve durability. The raw materials (oxides of aluminum, cerium, silicon, titanium, and zirconium) were not new, but were used in novel ways. Palladium (Pd) or rhodium (Rh) were supported either on layered metal oxide supports, on nanoparticles, or used in various core@shell configurations. Catalyst materials were aged hydrothermally to a simulated high mileage. The catalyst formulation with the lowest durable light-off was 0.5 wt% Rh supported on alumina with an overlayer of either Ti or Zr. The temperatures for 90% conversion were up to 128°C lower than those of a commercial Pd three-way catalyst that had > 3x metal loading of the new Rh catalyst. An additional material made of Pd supported on nanoparticles of ceria-zirconia (CZO) was also considered; the aged T90s were up to 40°C lower than the commercial catalyst, at similar metal loading. Further understanding of the catalyst architecture provided additional confidence to move forward with scale-up of 0.5 wt% Rh/Ti/Al 2 O 3 to coated monolith laboratory cores for further evaluation. The team worked with Johnson Matthey to accomplish this, in addition to exploring manufacturability and potential costs. The overall benefit was estimated to be 10-15% lower NMOG and NOx tailpipe emissions on a cold start certification cycle.

02 PETROLEUM↗
DOE OSTI2014

Soiling of building envelope surfaces and its effect on solar reflectance – Part II: Development of an accelerated aging method for roofing materials

Highly reflective roofs can decrease the energy required for building air conditioning, help mitigate the urban heat island effect, and slow global warming. However, these benefits are diminished by soiling and weathering processes that reduce the solar reflectance of most roofing materials. Soiling results from the deposition of atmospheric particulate matter and the growth of microorganisms, each of which absorb sunlight. Weathering of materials occurs with exposure to water, sunlight, and high temperatures. This study developed an accelerated aging method that incorporates features of soiling and weathering. The method sprays a calibrated aqueous soiling mixture of dust minerals, black carbon, humic acid, and salts onto preconditioned coupons of roofing materials, then subjects the soiled coupons to cycles of ultraviolet radiation, heat and water in a commercial weatherometer. Three soiling mixtures were optimized to reproduce the site-specific solar spectral reflectance features of roofing products exposed for 3 years in a hot and humid climate (Miami, Florida); a hot and dry climate (Phoenix, Arizona); and a polluted atmosphere in a temperate climate (Cleveland, Ohio). A fourth mixture was designed to reproduce the three-site average values of solar reflectance and thermal emittance attained after 3 years of natural exposure, which the Cool Roof Rating Council (CRRC) uses to rate roofing products sold in the US. This accelerated aging method was applied to 25 products₋single ply membranes, factory and field applied coatings, tiles, modified bitumen cap sheets, and asphalt shingles₋and reproduced in 3 days the CRRC's 3-year aged values of solar reflectance. In conclusion, this accelerated aging method can be used to speed the evaluation and rating of new cool roofing materials.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Effect of aging on lignin content, composition and enzymatic saccharification in Corymbia hybrids and parental taxa between years 9 and 12

Corymbia (a eucalypt) is an important forestry genus and a potential lignocellulosic bioenergy feedstock. The composition of the lignocellulosic cell wall significantly impacts pretreatment efficiency and conversion to biofuel but is variable and changes with age. In this study, we estimated Klason lignin content, composition, and monosaccharide (glucose and xylose) release after enzymatic saccharification of untreated and hydrothermally pretreated biomass from Corymbia parental species Corymbia torelliana (CT), Corymbia citriodora subsp. variegata (spotted gum; CCV), and interspecific F1 hybrids (CT x CCV) at ages 9 and 12 years from planting. Analysis of lignin composition derived from syringyl/guaiacyl monolignols (S/G) found significant differences among taxa, with CT S/G ratios (2.2 and 2.0) being significantly lower than CCV (2.6 and 2.3) or hybrids (2.5 and 2.3) at ages 9 and 12 respectively. In general, enzymatic saccharification yields from untreated biomass were significantly different among taxa, with CT (113 and 75 mg g -1 ) and hybrids (108 and 81 mg g -1 ) yielding significantly higher glucose from untreated biomass than CCV (82 and 56 mg g -1 ) at ages 9 and 12 respectively. Comparison of traits within taxa between ages 9 and 12 found S/G ratios and glucose yields from untreated biomass were significantly lower in CT, CCV and hybrid taxa. As a result, the formation of lignocellulosic cell walls is complex, influenced by genetics and age of material, requiring optimization of rotation age for biofuel production and other industrial processes.

09 BIOMASS FUELS↗
DOE OSTI2023

Status of Cable Aging Knowledge Gaps Identified in the Expanded Materials Degradation Assessment (EMDA)

This report summarizes research relevant to cable aging knowledge gaps identified in NUREG/CR-7153, “Expanded Materials Degradation Assessment (EMDA) Volume 5: Aging of Cables and Cable Systems” (EMDA Vol. 5), performed since the EMDA Vol. 5 was published in 2014. It begins with a discussion of the status of cables in long-term operation of U.S. nuclear power plants (NPPs) and the most common cables found in NPP containment. Next, the major polymer cable insulations, and the mechanisms of concern for degradation of those polymers in service are reviewed. A description of the environmental qualification (EQ) process historically used for safety-related cables is provided as is a review of the potential concerns with that process highlighted in the EMDA Vol. 5. Research addressing each of these is then reviewed. Finally, three potential strategies to support continued safe operation of aging cables are proposed: advanced condition-based verification, targeted material aging studies, and predictive simulation.

42 ENGINEERING↗
NASA NTRS1987

A preliminary mechanical property and stress corrosion evaluation of VIM-VAR work strengthened and direct aged Inconel 718 bar material

This report presents a preliminary mechanical property and stress corrosion evaluation of double melted (vacuum induction melted (VIM), and vacuum arc remelted (VAR)), solution treated, work strengthened and direct aged Inconel 718 alloy bar (5.50 in. (13.97 cm) diameter). Two sets of tensile specimens, one direct single aged and the other direct double aged, were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 200 ksi (1378.96 MPa) and 168 ksi (1158.33 MPa), respectively, were realized at ambient temperature, for the direct double aged specimen. No failures occurred in the single or double edged longitudinal and transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test showed no mechanical property degradation.

Montano, J. W.↗
DOE OSTI2018

Effect of thermal aging on oxide film of stainless steel weld overlay cladding exposed to high temperature water

Highlights: • Oxide film of aged cladding material in high temperature water was studied. • Thermal aging contributed to high corrosion susceptibility of the ferrite phase. • Highly corrosion of aged ferrite phase was caused by spinodal decomposition. • Carbides along phase boundary facilitated the corrosion of the cladding material. - Abstract: Characteristics of the oxide film formed on stainless steel weld overlay cladding aged at 400 °C for different times in high temperature water were studied. The results showed that thermal aging showed no obvious effect on the volume fraction of ferrite phase but resulted in high corrosion susceptibility of the aged ferrite phase mainly. The oxide film formed on the unaged cladding material consisted of 100-nm-thick inner oxide layer (FeCr{sub 2}O{sub 4} and Cr{sub 2}O{sub 3}) and Fe-rich outer oxide particles (Fe{sub 3}O{sub 4}) with a size of 2 O4, Cr{sub 2}O{sub 3} and Fe{sub 3}O{sub 4}) and outer oxide particles (Fe{sub 3}O{sub 4} and FeCr{sub 2}O{sub 4}) with a size of <700 nm formed on the aged ferrite phase. Spinodal decomposition was considered as the main factor to promote the corrosion of the aged ferrite phase, and existence of carbides along phase boundary facilitated corrosion of the cladding material in high temperature water.

36 MATERIALS SCIENCE↗
DOE OSTI2021

BACKFLIP: Identification of Materials and Changes Upon Aging of Emerging Fluoropolymer-Free and Industry-Benchmark PV Backsheets

Extending lifetimes of photovoltaic (PV) modules and decreasing manufacturing and decommissioning costs are motivating research of novel PV module backsheet materials. Backsheet integrity is critical to the safety and performance of a PV module, however, the polymeric materials are often vulnerable to environmental degradation. The long-term durability of emerging polyolefin (PO) materials is being examined to inform regarding the possible replacement of laminated backsheets containing polyethylene terephthalate (PET) cores and fluoropolymer protective inner/outer layers. This study compares traditional PET-based backsheets with novel, co-extruded, and recyclable PO-based backsheets after being subjected to hygrometric and UV photolytic accelerated weathering. A large set of characterization methods will compare physical, chemical, structural, mechanical, and insulating properties of these backsheets and the resulting mini-module (MiMo) PV performances. The study of chemical composition, glass- and phase-transition temperatures, degree of crystallinity, and crystalline structure are described here.

mini-module↗
DOE OSTI2023

Aging studies of Dual functional materials for CO 2 direct air capture with in situ methanation under simulated ambient conditions: Ru thrifting for cost reduction

Dual function materials (DFMs) comprised of 0.25 %Ru, 6.1 %Na 2 O/γ-Al 2 O 3 //monolith were evaluated for about 250 hours time-on-stream (TOS) at various simulated ambient climate capture conditions followed by temperature swing methanation to 280 °C. Herein this paper focuses on the impact of thrifting Ru to low levels and the impact on performance. Results showed both stable CO 2 capture capacity and CH 4 production with 0.25 % Ru DFM deposited on a ceramic monolith. The CO 2 conversion to CH 4 production was decreased slightly by the Ru decrease from 1 % to 0.25 %. The capture capacity decreased since a lower Ru content reduces the complete decomposition of the Na 2 CO 3 precursor producing fewer active adsorption sites (“Na 2 O”). The deployment of a low Ru DFM monolith would significantly decrease the overall capital cost and give more potential for a large-scale direct air capture and methanation (DACM) application.

03 NATURAL GAS↗
NASA NTRS2015

Method and Apparatus for Non-Destructive Evaluation of Materials

Methods and apparatus for characterizing composite materials for manufacturing quality assurance (QA), periodic inspection during the useful life, or for forensic analysis/material testing. System are provided that relate eddy-current sensor responses to the fiber layup of a composite structure, the presence of impact damage on a composite structure with or without a metal liner, volumetric stress within the composite, fiber tow density, and other NDE inspection requirements. Also provided are systems that determine electromagnetic material properties and material dimensions of composite materials from capacitive sensor inspection measurements. These properties are related to the presence of buried defects in non-conductive composite materials, moisture ingress, aging of the material due to service or environmental/thermal exposure, or changes in manufacturing quality.

Goldfine, Neil J.↗
NASA NTRS2017

Method and Apparatus for Non-Destructive Evaluation of Materials

Methods and apparatus for characterizing composite materials for manufacturing quality assurance (QA), periodic inspection during the useful life, or for forensic analysis/material testing. System are provided that relate eddy-current sensor responses to the fiber layup of a composite structure, the presence of impact damage on a composite structure with or without a metal liner, volumetric stress within the composite, fiber tow density, and other NDE inspection requirements. Also provided are systems that determine electromagnetic material properties and material dimensions of composite materials from capacitive sensor inspection measurements. These properties are related to the presence of buried defects in non-conductive composite materials, moisture ingress, aging of the material due to service or environmental/thermal exposure, or changes in manufacturing quality.

Goldfine, Neil J.↗
NASA NTRS2017

Precipitation Strengthenable NiTiPd High Temperature Shape Memory Alloys

In binary NiTi alloys, it has long been known that Ni-rich alloys can be heat treated to produce precipitates which both strengthen the matrix against dislocations and improve the behavior of the material under thermal and mechanical cycling. Within recent years, the same effect has been observed in Ni-rich NiTiHf high temperature shape memory alloys and heat treatment regimens have been defined which will reliably produce improved properties. In NiTiPd alloys, precipitation has also been observed, but studies are still underway to define reliable heat treatments and compositions which will provide a balance of strengthening and good thermomechanical properties. For this study, a series of NiTi-32 at.Pd alloys was produced to determine the effect of changing nickeltitanium content on the transformation behavior and heat treatability of the material. Samples were aged at temperatures between 350C and 450C for times up to 100 hours. Actuation type behavior was evaluated using uniaxial constant force thermal cycling (UCFTC) to determine the effect of composition and aging on the material behavior. TEMSEM was used to evaluate the microstructure and determine the types of precipitates formed. The correlation between composition, heat treat, microstructure, and thermomechanical behavior will be addressed and discussed.

Transformation strain↗