Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “FORMING”

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 307 records · Page 17

OAST Theme Workshop. Volume 3: Working group summary. 8: Structures, dynamics (M-2). A. Statement. B. Technology needs (form 1). C. Priority assessments (form 2)

A technology program on large space structures was defined to respond to common need perceived for five of the six themes. Greatly expanded power, facilities, and communications/sensing requirements appear to demand a new structures technology for construction in space. Requirements to construct huge structural arrays with precision surfaces in space will need creative research efforts to identify practical structural elements and construction techniques. Requirements for advanced transportation structures were defined to respond to the space transportation theme. Because of the criticality of thermal structures to achieve lower cost transportation systems, renewed emphasis on technology in this area is recommended. A second technology needing renewed emphasis is the area of recovery and landing technology structures to permit full reuse of launch vehicle propulsion elements.

Source record↗

OAST Space Theme Workshop. Volume 3: Working group summary. 9: Aerothermodynamics (M-3). A: Statement. B: Technology needs (form 1). C. Priority assessment (form 2). D. Additional assessments

Twelve aerothermodynamic space technology needs were identified to reduce the design uncertainties in aerodynamic heating and forces experienced by heavy lift launch vehicles, orbit transfer vehicles, and advanced single stage to orbit vehicles for the space transportation system, and for probes, planetary surface landers, and sample return vehicles for solar system exploration vehicles. Research and technology needs identified include: (1) increasing the fluid dynamics capability by at least two orders of magnitude by developing an advanced computer processor for the solution of fluid dynamic problems with improved software; (2) predicting multi-engine base flow fields for launch vehicles; and (3) developing methods to conserve energy in aerothermodynamic ground test facilities.

Source record↗

The hydrodynamic role of fish squamosal integument as an analog of surfaces directly formed by turbulent flow. Report 1: Similarity between irregularities in squamosal integument and those on surfaces formed by river bed flow

The distribution of squamae on the fish body and that of the deposits in the bed of the river can be described by the same equation. The curves reflecting the relative elongation and stability of the body shape of the fish continue the curves showing the elongation of bank spit and stability of the bed of the river.

Kudryashov, A. F.↗

The Influence of the Form of a Wooden Beam on Its Stiffness and Strength II : Form Factors of Beams Subjected to Transverse Loading Only

The general aim of the investigation described in this report is the achievement of efficient design in wing beams. The purpose of the tests was to determine factors to apply to the usual beam formula in order that the properties of wood based on tests of rectangular sections might be used as a basis of design for beams of any sections and if practical to develop formulas for determining such factors and to verify them by experiment. Such factors for various sections have been determined from test by comparing properties of the beam in question to similar properties of matched beams 2 by 2 inches in section. Furthermore, formulas were worked out, more or less empirical in character, which check all of these test values remarkably well.

Newlin, J A↗

Analysis of Base Metal Microstructures and Mechanical Properties of a Single-Piece, Spin-Formed Forward Pressure Vessel Bulkhead

In 2012, a pathfinder forward pressure vessel bulkhead (FPVBH) for the Orion Multi-Purpose Crew Vehicle (MPCV) was fabricated using aluminum (Al) alloy 2219. The demonstration article was offered as a replacement for the baseline configuration, which at that time was a multi-piece welded construction using aluminum-lithium (Al-Li) alloy 2195. In 2014, the NASA Engineering and Safety Center (NESC) funded a Phase I effort to explore spin-forming as a manufacturing method to produce a complex-shaped, single-piece FPVBH for the crew module (CM) [1]. The primary focus of the NESC effort was to expand spin-forming technology to the fabrication of an Al-Li 2195 FPVBH. As a result, limited testing and analysis was performed on the original Al 2219 article. In this study, a sufficiently large plate of Al 2219 was not available for the fabrication of a FPVBH. Therefore, the forming blank comprised two plates (from different lots) butt welded together using a single friction stir weld. The welded forming blank was then spin formed into the FPVBH configuration and heat treated to the T62 temper. Mechanical property testing of the spin-formed 2219-T62 FPVBH revealed that the tensile properties were comparable to the Metallic Material Properties Development and Standardization (MMPDS) A-basis allowable for Al 2219-T6 wrought products. However, post-spin forming application of the standard heat treatment produced large, recrystallized grains in the material. The response varied within the two plates; one plate lot exhibited nearly complete recrystallization, while the other lot contained bands of recrystallization. Although no reduction in tensile properties was observed due to these microstructural variations, a more detailed investigation was recommended to better understand the effect of spin forming on the recrystallization mechanism and the impact on other material properties. The current study examined the microstructure and mechanical properties of the fully processed Al 2219-T62 FPVBH with emphasis on comparing differences between the two plates. Testing was limited to the cone region of the FPVBH. The two specific tasks in this study were: a) Characterization of the microstructure and mechanical properties in the two plates used in the FPVBH. b) Isolation of the impact of each step in the thermo-mechanical processing (TMP) sequence of the FPVBH on recrystallization and grain growth. Mechanical property testing sampled regions containing both large, recrystallized and small, unrecrystallized grains. Tensile strengths and elongations were equivalent in both regions and exceeded MMPDS A-basis allowables. Fracture toughness was equivalent in both regions and fracture morphology was typical of aluminum alloys. The fatigue precrack region of the fracture toughness specimens appeared more faceted in the recrystallized plate. This suggests that property testing that is more sensitive to grain size, such as fatigue crack growth rate and stress corrosion cracking, may be warranted. Alcoa reviewed the production records for the two plate lots and confirmed that composition of both plates was within the allowable range for Al 2219 and that plate processing steps were all performed within production limits. However, the Fe content was notably higher in the fully recrystallized plate, resulting in a greater volume fraction of large Fe-bearing inclusions and Al-Cu constituent particles. Alcoa did not provide details regarding plate processing variables for the two plate lots. It was surmised that deformation by hot rolling was the most accurate TMP simulation of commercial spin forming within a laboratory setting. Both hot rolling and spin forming comprise combinations of shear and compressive deformation. The through-thickness strain caused by hot rolling is symmetrical about the mid-plane, as the rollers contact both sides of the material. Shear strains are maximum at the inner and outer surfaces and trend toward zero at the mid-thickness. In contrast, spin forming utilizes a single roller on the outer surface, producing a gradient in shear stress through the thickness. Shear strains in spin-formed material are highest at the outer surface due to direct contact with the roller, and trend toward zero at the inner surface. Consequently, there will undoubtedly be some discrepancies in the mechanical response of hot-rolled and spin-formed products in the through-thickness direction. Interrupted TMP simulations were performed on remnant plate from the FPVBH forming blank in order to isolate the effects of a post-weld anneal, spin-forming deformation/thermal cycling, and solution heat treatment (SHT) on development of the recrystallized microstructures. Analysis confirmed that large, recrystallized grains formed exclusively during SHT and only after a certain deformation level was exceeded. Remnant plate from both lots that received thermal processing only did not exhibit recrystallization but exhibited fully recrystallized microstructures when processed by hot rolling. This indicates that (1) the level of deformation exceeded the critical level for recrystallization in both plates and (2) that the level of deformation during hot rolling was greater than that which accumulated during spin forming of the FPVBH. Comparison of the hot-rolled plate with the spin-formed material showed that the recrystallized grain size was larger in the FPVBH, providing further evidence that deformation levels were lower in the FPVBH. The most plausible explanation for the differing degrees of recrystallization in the two plates is particle stimulated nucleation (PSN) at the Fe-bearing inclusions and large Al-Cu constituent particles. In the plate with higher solute content, the greater volume fraction of these particles reduces the deformation level required to promote recrystallization. During spin forming the critical deformation level was likely exceeded for the higher Fe content plate resulting in a fully recrystallized microstructure. The lower Fe content plate developed a microstructure that exhibited bands of recrystallization due to the combination of a non-uniform distribution of particles and deformation. The critical deformation required for recrystallization was likely only exceeded during spin forming in regions of higher particle content. While there were differences in Fe content between these lots of Al 2219 plate, the composition of both was within defined alloy limits and Alcoa reported no anomalies during plate production. The observed differences in recrystallization after spin forming may reflect the inherent variability between these two lots of plate. The spin-forming vendor, Spincraft, reported that similar variations in recrystallized microstructures have been observed during examination of multiple spin-forming trials of a different 2xxx series aluminum alloy. Hence, tighter chemical specification limits on impurity levels in Al 2219 plate may help ensure uniform, predictable microstructures. Finally, the tensile and fracture toughness properties were not affected by the microstructural variations noted.

single-piece↗

Performance Test on Polymer Waste Form - 12137

Polymer solidification was attempted to produce stable waste form for the boric acid concentrates and the dewatered spent resins. The polymer mixture was directly injected into the mold or drum which was packed with the boric acid concentrates and the dewatered spent resins, respectively. The waste form was produced by entirely curing the polymer mixture. A series of performance tests was conducted including compressive strength test, water immersion test, leach test, thermal stability test, irradiation stability test and biodegradation stability test for the polymer waste forms. From the results of the performance tests for the polymer waste forms, it is believed that the polymer waste form is very stable and can satisfy the acceptance criteria for permanent disposal. At present, performance tests with full scale polymer waste forms are being carried out in order to obtain qualification certificate by the regulatory institute in Korea. Polymer waste forms were prepared with the surrogate of boric acid concentrates and the surrogate of spent ion exchange resins respectively. Waste forms were also made in lab scale and in full scale. Lab. scale waste forms were directly subjected to a series of the performance tests. In the case of full scale waste form, the test specimens for the performance test were taken from a part of waste form by coring. A series of performance tests was conducted including compressive strength test, thermal stability test, irradiation stability test and biodegradation stability test, water immersion test, leach test, and free standing water for the polymer waste forms. In addition, a fire resistance test was performed on the waste forms by the requirement of the regulatory institute in Korea. Every polymer waste forms containing the boric acid concentrates and the spent ion exchange resins had exhibited excellent structural integrity of more than 27.58 MPa (4,000 psi) of compressive strength. On thermal stability testing, biodegradation testing and water immersion testing, no degradation was observed in the waste forms. Also, by measuring the compressive strength after these tests, it was confirmed that the structural integrity was still retained. A leach test was performed by using non radioactive cobalt, cesium and strontium. The leaching of cobalt, cesium and strontium from the polymer waste forms was very low. Also, the polymer waste forms were found to possess adequate fire resistance. From the results of the performance tests, it is believed that the polymer waste form is very stable and can satisfy the acceptance criteria for permanent disposal. At present, Performance tests with full scale polymer waste forms are on-going in order to obtain qualification certificate by the regulatory institute in Korea. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Field-Scale Lysimeter Studies of Glass and Cementitious Waste Forms at the Hanford Site - 20392

The Hanford site Integrated Disposal Facility (IDF) will receive waste forms from vitrification activities at the Hanford Waste Treatment and Immobilization Plant (WTP). The waste form inventory to be disposed of at the IDF will consist of vitrified low-activity waste (LAW) in glass forms and solidified (or encapsulated) secondary wastes in cementitious forms. The IDF is a near-surface burial facility located near Hanford's Waste Treatment and Immobilization Plant in the 200 East Area of the site's Central Plateau. An extensive set of laboratory experimental data has been collected to support IDF performance assessment calculations of the eventual degradation of waste forms and mobility of contaminants. This paper describes the start of a field experiment to generate waste-form performance data on a larger scale (tens of centimeters), over a longer duration (five years or more), and under field conditions representative of the IDF. Results from this study are expected to improve model descriptions of contaminant mobility, reduce uncertainties about the representativeness of laboratory results in the IDF performance assessment, improve stakeholder confidence in the safe disposal of treated waste at the IDF, and facilitate the adoption of informed facility designs with the potential to reduce operational costs. A lysimeter test facility near Hanford's 200 West Area has been repurposed to carry out long-term assessments of waste forms buried in sediments excavated from the IDF. The waste forms are buried in large drainage lysimeters, open caissons that are two meters in diameter and three meters deep. Waste forms are buried in up to six locations in each lysimeter. Samplers collect pore water and drainage water beneath the waste forms and air from the pore space adjacent to waste forms. Sensors measure temperature, soil water content, soil water tension, and drainage flux. One lysimeter containing cementitious waste forms and one containing glass waste forms have been completed, along with a control lysimeter (without waste forms). The cementitious waste forms are Cast Stone grout formulations using a liquid secondary waste simulant and a generic Hanford high-salt simulant, as well as a hydrated lime-based grout formulation using a liquid secondary waste simulant. Technetium-99 and iodine-127 were added as tracers to monitor contaminant mobility. Glass waste forms were fabricated in two formulations (LAWA44 and ORLEC28), with rhenium and molybdenum tracers to monitor waste form degradation. The predicted performance of the waste forms in the lysimeters was modeled prior to installation to determine waste form size, tracer concentration/activity, and locations of sensors and samplers. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Evaluation of Engineered Form MOFs CaSDB and HKUST-1

Idaho National Laboratory (INL) and Pacific Northwest National Laboratory (PNNL) have studied different sorbents for the purpose of separating krypton (Kr) and xenon (Xe). PNNL has researched various metal-organic frameworks (MOFs) that have characteristics theoretically suitable for the separation. Based on computational analysis, PNNL chose Calcium–4,4’–sulfonyl dibenzoate (CaSDB) and Hong Kong University of Science and Technology MOF1 (HKUST–1). The raw MOFs are supplied in a powder form and must be incorporated into a robust engineered form to be viable for gas separation. In 2016, PNNL produced an engineered form of CaSDB by compressing and grinding the raw MOF material. This form was sent to INL for adsorption testing. Gentle mechanical agitation of the compressed form produced a large amount of powder, resulting in the conclusion that the form was not viable for the application. In 2019, INL successfully produced two engineered forms, CaSDB–EF1 and HKUST–EF2, by incorporating the active MOF powders into a polyacrylonitrile (PAN) binder. PNNL also produced two engineered forms, CaSDB–10pmma and HKUST–10pmma, by using polymethyl methacrylate (PMMA) as a binder. Surface area analysis indicated that the forms could be viable for separations in which the CaSDB–EF1 retained 84% of the raw CaSDB surface area and CaSDB–10pmma retained 48%. HKUST–EF2 retained all the raw HKUST–1 surface area, whereas HKUST–10pmma retained only 28%. Mechanical stability testing demonstrated that the PMMA forms formed a fine powder whereas, the PAN forms did not. In general, adsorption testing showed that CaSDB–10pmma had a lower Xe breakthrough capacity than CaSDB–EF1, but a higher saturation capacity at both room temperature and at 253 K. The CaSDB MOF was intended to be used as a room temperature sorbent to capture Xe. However, both CaSDB engineered forms displayed relatively short initial break through times. Reduced temperature increased the Xe capacity of both engineered forms. HKUST–1 was expected to be effective only at sub-zero temperatures. At 195 K, HKUST–10pmma had an initial Xe breakthrough capacity of 119 mmol/ kg, compared to HKUST–EF2 at 339 mmol/ kg. The saturation capacities were 275 and 383 mmol/ kg, respectively. HKUST–10ppm also had a lower Kr capacity of 1.7 mmol/kg, whereas the HKUST–EF had a Kr capacity of 3 mmol/ kg. Test results indicate that the PAN engineered forms are a more suitable choice for the complete separation of Xe and Kr, due to the increase in initial breakthrough capacity. CaSDB allows rapid breakthrough of Kr and Xe regardless of the type of engineered form. At 253 K, it is more viable, but is still not the most effective sorbent. HKUST–EF2 demonstrated viability for Xe capture at 195 K, which may merit further study, however it may be cost prohibitive.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Machining Elimination through Application of Thread Forming Fasteners in Net-Shaped Cast Holes

The ultimate objective of this work was to eliminate approximately 30% of the machining performed in typical automotive engine and transmission plants by using thread forming fasteners in as-cast holes of aluminum and magnesium cast components. The primary issues at the source of engineers reluctance to implementing thread forming fasteners in lightweight castings are: • Little proof of consistency of clamp load vs. input torque in either aluminum or magnesium castings. • No known data to understand the effect on consistency of clamp load as casting dies wear. The clamp load consistency concern is founded in the fact that a portion of the input torque used to create clamp load is also used to create threads. The torque used for thread forming may not be consistent due to variations in casting material, hole size and shape due to tooling wear and process variation (thermal and mechanical). There is little data available to understand the magnitude of this concern or to form the basis of potential solutions if the range of clamp load variation is very high (> +/- 30%). The range of variation that can be expected in as-cast hole size and shape over the full life cycle of a high pressure die casting die was established in previous work completed by Pacific Northwest National Laboratory, (PNNL). This established range of variation was captured in a set of 12 cast bosses by designing core pins at the size and draft angles identified in the sited previous work. The cast bosses were cut into nuts that could be used in the Ford Fastener Laboratory test-cell to measure clamp load when a thread forming fastener was driven into a cast nut. There were two sets of experiments run. First, a series of cast aluminum nuts were made reflecting the range of shape and size variations to be expected over the life cycle of a die casting die. Taptite thread forming fasteners, (a widely used thread forming fastener suitable for aluminum applications), were driven into the various cored, as-cast nuts at a constant input torque and resulting clamp loads were recorded continuously. The clamp load data was used to determine the range of clamp loads to be expected. The bolts were driven to failure. The clamp load corresponding to the target input of 18.5 Nm was recorded for each fastener. In a like fashion, a second set of experiments were run with cast magnesium nuts and ALtracs thread forming fasteners, (a widely used thread forming fastener suitable for magnesium applications). Again all clamp loads were recorded and analyzed similarly to the Taptites in aluminum cast nuts. Results from previous work performed on the same test cell for a Battelle project using standard M8 bolts into standard M8 nuts were included as a comparator for a standard bolt and nut application. The results for the thread forming fasteners in aluminum cast holes were well within industry expectations of +/- 30% for out of the box and robustness range testing. The results for the dry and lubed extreme conditions were only slightly higher than industry expectations at +/- 35.6%. However, when compared to the actual Battelle results (+/- 40%) for a standard bolt and nut the tread forming fasteners performed slightly better. The results for the thread forming fasteners in magnesium cast holes were all well within industry expectations of +/- 30% for all three conditions. The robustness range (.05mm larger and smaller holes than the expected wear pattern of a die casting die at full life cycle) results also fell within the industry expectations for standard threaded fasteners. These results were very encouraging. It was concluded that this work showed that clamp load variation with thread forming fasteners is consistent with industry expectations for standard steel bolts and nuts at +/- 30%. There does not appear to be any significant increase in clamp load variation due to the application of thread forming fasteners in as-cast holes of aluminum or magnesium over the effective life of a die casting mold. The fully implemented potential benefit of thread forming fasteners in as-cast holes of aluminum and magnesium is estimated to be 6 trillion Btu per year for North America. Economic benefit is estimated to be nearly $800 million per year. Environmental benefits and quality improvements will also result from full implementation of this technology.

36 MATERIALS SCIENCE↗

Extraction and Parametrization of Isobaric Trinucleon Elastic Cross Sections and Form Factors

By mining data from Jefferson Lab Hall A experiment E08-014 a new 3 He elastic cross section was extracted from a large quasielastic background. This measurement was taken with an initial beam energy of 3.356 GeV and an angle of 20.51°. The cross section was found to be 1.345 × 10 -6 µb/sr ± 0.086 × 10 -6 µb/sr at Q 2 = 34.19 fm -2 . This new data point falls approximately halfway between the first and second diffractive minima of the 3 He form factors. When combined with recent high Q 2 3 He elastic cross section measurements from Jefferson Lab and MIT-Bates this new data point improves our knowledge of the cross section and form factors at large momentum transfers. The new high Q 2 data motivate a reanalysis of the 3 He elastic cross section world data and provide an improved understanding of the magnetic form factor in particular. For this analysis the elastic cross section world data for 3 He, and its mirror nuclei 3 H, were collected. The world data spans a time frame from 1965 to 2016. The dataset contains electron energy ranges from tens of MeV to above 12 GeV for measurements performed at many different facilities. The world data were then fit using a sum of Gaussians parametrization which allowed for the extraction of both targets’ magnetic and electric form factors which were then used to calculate charge densities and radii. The new charge and magnetic form factors for 3 H and the charge form factor for 3 He are in good agreement with the 1994 fits from Amroun et al . However, the addition of the new high Q 2 data has caused the 3 He magnetic form factor’s first diffractive minimum to shift up in Q 2 by 1-3 fm -2 while also decreasing the magnitude of the magnetic form factor above Q2 ≈ 20 fm -2 . The first diffractive minima for 3H are located at Q2 ≈ 13 fm -2 and Q 2 ≈ 23-24 fm -2 for the charge and magnetic form factors respectively. The first diffractive minima for 3 He are located at Q 2 ≈ 11 fm -2 and Q 2 ≈ 17-20 fm -2 for the charge and magnetic form factors respectively. The charge radius for 3 He was found to be 1.90 fm ± 0.00144 fm in reasonable agreement with past measurements, and the charge radius for 3 H was found to be 2.02 fm ± 0.0133 fm which is much larger than past measurements. However, each of these charge radii has an additional uncertainty that must be applied to them due to allowing all parameters to float freely during the sum of Gaussians fitting procedure. This additional uncertainty should be small for 3 He, but it is likely quite significant for 3 H and would help bring this charge radius closer to agreement with past measurements that made different fitting choices. Unfortunately, this analysis was unable to quantify this additional uncertainty. The new form factor fits were compared to modern theoretical predictions from the 2016 paper of Marcucci et al . The ‘conventional’ theoretical approach applied in this paper modelled two and three-body nucleon interactions with relativistic corrections and was reasonably successful at predicting the charge form factors of 3 H and 3 He. χEFT predictions were also often successful. However, while the ‘conventional’ approach still performed best, theory failed to accurately predict the magnetic form factors of either 3 H or 3 He. The first diffractive minimum of the new 3 He magnetic form factor fits actually moved further away from theory. This disagreement between theory and experiment provides motivation for new asymmetry measurements using polarized 3 He and a polarized electron beam. When the beam is scanned in Q 2 on the target the sign of the asymmetry will flip at the form factor minima pinning down their true location.

Barcus, Scott↗

Microstructure evolution of 7050 Al alloy during age-forming

The microstructure evolution of the 7050 Al alloy treated by age-forming was studied using a designed device which can simulate the age-forming process. The grain shape, grain boundary misorientation and grain orientation evolution of 7050 Al alloy during age-forming have been quantitatively characterized by electron backscattering diffraction technique. The results show that age-forming produced abundant low-angle boundaries and elongated grains, which attributed to stress induced dislocation movement and grain boundary migration during the age-forming process. On the other side, the stress along rolling direction caused some unstable orientation grains to rotate towards the Brass and S orientations during the age-forming process. Hence, the intensity of the rolling texture orientation in age-formed samples is enhanced. But this effect decays gradually with increasing aging time, since stress decreases and precipitation hardening occurs during the age-forming process. - Highlights: • Quantitative analysis of grain evolution of 7050 Al alloys during age-forming • Stress induces some grain rotation of 7050 Al alloys during age-forming. • Creep leads to elongate grain of 7050 Al alloys during age-forming. • Obtains a trend on texture evolution during age-forming applied stress.

36 MATERIALS SCIENCE↗

Secondary Waste Cast Stone Waste Form Qualification Testing Plan (Rev.1)

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is being constructed to treat the 56 million gallons of radioactive waste stored in 177 underground tanks at the Hanford Site. The WTP includes a pretreatment facility to separate the wastes into high-level waste (HLW) and low-activity waste (LAW) fractions for vitrification and disposal. The LAW will be converted to glass for final disposal at the Integrated Disposal Facility (IDF). Cast Stone – a cementitious waste form, has been selected for solidification of this secondary waste stream after treatment in the ETF. The secondary-waste Cast Stone waste form must be acceptable for disposal in the IDF. This secondary waste Cast Stone waste form qualification testing plan outlines the testing of the waste form and immobilization process to demonstrate that the Cast Stone waste form can comply with the disposal requirements. Specifications for the secondary-waste Cast Stone waste form have not been established. For this testing plan, Cast Stone specifications are derived from specifications for the immobilized LAW glass in the WTP contract, the waste acceptance criteria for the IDF, and the waste acceptance criteria in the IDF Permit issued by the State of Washington. This testing plan outlines the testing needed to demonstrate that the waste form can comply with these waste form specifications and acceptance criteria. The testing program must also demonstrate that the immobilization process can be controlled to consistently provide an acceptable waste form product. This testing plan also outlines the testing needed to provide the technical basis for understanding the long-term performance of the waste form in the disposal environment. These waste form performance data are needed to support performance assessment analyses of the long-term environmental impact of the secondary-waste Cast Stone waste form in the IDF

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Research Roadmap on Grid-Forming Inverters

This research roadmap is intended to fill the knowledge gap by providing a system view of grid-forming inverter-based resource controls and their impact on grid stability, which we believe is central to meeting some of the challenges to operating the future North American electric power system. This includes the roles and requirements of grid-forming inverter-based resources—including solar photovoltaics, wind generators, and energy storage. For this roadmap, we focus on a specific family of grid-forming inverter control approaches that do not rely on an external voltage source (i.e., no phase-locked loop) and that can share load without explicit communications. Although the roadmap is focused narrowly on system challenges for grid-forming controls and power system stability, including interactions with protection, we hope it serves as a foundational element for future system-of-systems roadmapping needed in a broader grid modernization effort with increasing deployments of inverter-based resources. The roadmap first introduces formal definitions for the grid stability topics and then describes the differences between grid-forming and traditional grid-following control approaches for inverter-based resources. The core of the roadmap consists of a review of current research and an outline of research needs related to five grid-forming inverter topics: frequency control, voltage control, system protection, fault ride-through and voltage recovery, and modeling and simulation. The review both delineates contemporary advances and highlights open research questions that must be addressed to enable the widespread adoption of inverter-based resources across the grid. Feedback from industry on these research questions is incorporated, including discussions during the Workshop on Grid-forming Inverters for Low-inertia Power Systems. The workshop included industry presentations and discussion of ongoing research, technology gaps, and piloting needs. This roadmap concludes by offering a multiyear perspective on the gradual field validation of grid-forming inverters. This perspective recognizes that the scale and scope of the types of power systems that inverters will be called on to provide grid-forming services will and should begin modestly. Specifically, this roadmap recognizes that inverter controls today are predominantly grid-following and that future power systems will involve a mix of inverter-based resources with both grid-following and grid-forming control capabilities. Growth over time will depend on how well grid-forming inverters perform and what advantages they bring as penetration levels (instantaneous and average) of inverter-based resources increases. This recognition, in turn, establishes a natural sequence of priorities for the research questions that must be addressed. Following this multiyear perspective, the roadmap offers short descriptions of two specific near-term research priorities: the review of regulatory and technical standards and the development of advanced modeling techniques. These priorities are foundational. We recommend immediate pursuit of them in parallel with and in direct support of the research outlined by our multiyear perspective.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Research on Resistance Heating Behavior of High-Strength Steel and its Hot-Stamping Forming

A hot-stamping process of high-strength steel sheet using resistance heating (RH) was developed to improve springback and formability. The RH curves of S355J2W steel and the microstructure and mechanical properties after RH were explored to control and guide the RH time and the selected current density for the subsequent RH hot-stamping forming. Moreover, scanning electron microscopy observations revealed the microstructure evolution in RH and the improvement of mechanical properties at a current density of 0-6.67 A mm{sup −2}, showing the advantage of the application of RH to these materials. The results showed that steel strength can be increased by up to 3.2% and the elongation can be improved by up to 33% after RH. In addition, the forming height increased and the forming angle is closer to the desired angle with the increased current density in cap-shaped RH hot-stamping forming experiment, which means that the forming accuracy is improved. A comparison of the forming accuracy of cap-shaped parts formed by RH under different current densities with those heated to the same temperature by furnace heating (FH) shows that there is no obvious difference between them. The heating time of RH is much shorter than that of the FH, and the surface quality of the parts formed by RH hot-stamping is better than that of the parts formed by FH hot-stamping. These results demonstrate that the RH method has the advantages of efficiency, safety, energy saving and the improvement of surface quality as well as a clear understanding of the benefits of RH hot-stamping forming for materials properties and forming accuracy; this work also develops and applies fundamental theory to practical engineering of bogie cover plate manufacturing.

36 MATERIALS SCIENCE↗

Hydropower Capital and O&M Costs: An Exploration of the FERC Form 1 Data

This report explores the potential for using responses from the Federal Energy Regulatory Commission’s (FERC’s) “Electric Utility Annual Report,” also known as FERC Form 1, as a cost database for conventional and pumped storage hydropower (PSH). The report outlines the process used to compile an easy-to-access database from the original FERC Form 1 data and discusses the historical cost/performance data. The steps for developing the database include downloading the annual FoxPro files from the FERC website (FERC, 2020), reading them into an Excel format, and reconciling naming issues across years, repeated entries, and shared assets, among others. The cleaned and compiled Form 1 database is available on Oak Ridge National Laboratory’s (ORNL’s) HydroSource website. For this report, the compiled Form 1 database was linked to two other hydropower databases, the National Inventory of Dams and the ORNL Existing Hydropower Assets, that provide additional information on the characteristics and other features of plants in the Form 1 data. Explorations of the plant characteristics, performance, capital costs, and operation and maintenance (O&M) cost data in the combined database were presented separately for conventional hydropower and PSH projects. Form 1 has several advantages as a hydropower cost database. First, the cost data is reported directly by plant owners. Second, Form 1 provides cost breakdowns of capital and operating costs for large conventional and PSH plants enabling more detailed tracking of hydropower costs compared with typical total cost estimates. Third, although the Form 1 data is not reported by all operational hydropower plants in the United States, the available data represents a wide range of plant characteristics and a sizable proportion of the hydropower fleet (61% of PSH plants and 22% of conventional hydropower plants by capacity). The lower proportion of the conventional hydropower fleet is because Form 1 reporting requirements apply only to private utilities that meet given size thresholds, leaving out federally owned facilities and many smaller hydropower plants. Overall, the Form 1 cost database represents a unique, publicly available database on hydropower asset capital and O&M costs. This report leads to a compiled database for the reporting years 1994 to 2020 that helps resolve issues with accessibility and use of the FERC Form 1 data by hydropower plant owners, project developers, technology developers, and regulators.

13 HYDRO ENERGY↗

Validation of Interconnection and Interoperability of Grid-Forming Inverters Sourced by Hydrogen Technologies in View of 100% Renewable Microgrids

Grid-forming assets are required in microgrids to act as voltage-frequency masters. These grid-forming assets can operate in two modes of operation: grid-following mode and grid-forming mode. In grid-following mode of operation, these assets will follow real power and reactive power setpoints and in grid-forming mode of operation these assets will follow voltage and frequency setpoints. Traditionally, diesel generators or natural gas-based generators are widely used to act as a voltage-frequency master. However, many utilities are aiming to replace generators with grid forming-inverters supplied by solar photovoltaics (PV), batteries or fuel cells. Since grid-forming assets need a long-term reliable energy source, fuel cells are a reasonable and viable choice to supply the grid-forming inverters, but some of the challenges facing the wide deployment of grid-forming fuel cell inverters need to be addressed. Specifically, in our proposed work, we aim to focus on the interconnection and interoperability requirements of grid-forming fuel cell inverters. Currently, state-of-the-art fuel cell inverters follow the general interconnection requirements of distributed energy resources (DERs) and general interoperability requirements of DERs, but these requirements were built with PV and battery systems in mind. Fuel cells have different operational requirements, and therefore these requirements need to be appropriately modified for the grid operators to use. These additional steps add to the investment and operational cost to the grid operators. Through the ARIES platform, this proposed project aims to bridge this gap and use power hardware-in-the-loop (PHIL) and controller hardware-in-the-loop (CHIL) experiments to inform the creation of open-source interconnection and interoperability information that can aid in faster and cheaper installation and operation of grid-forming fuel cell inverters.

controller hardware-in-the-loop↗

Validation of Interconnection and Interoperability of Grid-Forming Inverters Sourced by Hydrogen Technologies in View of 100% Renewable Microgrids

Grid-forming assets are required in microgrids to act as voltage-frequency masters. These grid-forming assets can operate in two modes of operation: grid-following mode and grid-forming mode. In grid-following mode of operation, these assets will follow real power and reactive power setpoints and in grid-forming mode of operation these assets will follow voltage and frequency setpoints. Traditionally, diesel generators or natural gas-based generators are widely used to act as a voltage-frequency master. However, many utilities are aiming to replace generators with grid forming-inverters supplied by solar photovoltaics (PV), batteries or fuel cells. Since grid-forming assets need a long-term reliable energy source, fuel cells are a reasonable and viable choice to supply the grid-forming inverters, but some of the challenges facing the wide deployment of grid-forming fuel cell inverters need to be addressed. Specifically, in our proposed work, we aim to focus on the interconnection and interoperability requirements of grid-forming fuel cell inverters. Currently, state-of-the-art fuel cell inverters follow the general interconnection requirements of distributed energy resources (DERs) and general interoperability requirements of DERs, but these requirements were built with PV and battery systems in mind. Fuel cells have different operational requirements, and therefore these requirements need to be appropriately modified for the grid operators to use. These additional steps add to the investment and operational cost to the grid operators. Through the ARIES platform, this proposed project aims to bridge this gap and use power hardware-in-the-loop (PHIL) and controller hardware-in-the-loop (CHIL) experiments to inform the creation of open-source interconnection and interoperability information that can aid in faster and cheaper installation and operation of grid-forming fuel cell inverters.

grid-forming↗