Transition to Mission Applications
Transition emerging phased-array metamaterial DR research to sensing, imaging, and communications applications.
36 MATERIALS SCIENCE↗
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NDE Reliability Issues for the Examination of CASS Components
The relatively low cost and corrosion resistance of cast austenitic stainless steel (CASS) materials resulted in their extensive use for piping systems in nuclear power plants (NPPs). However, CASS component welds are among the most challenging volumetric examinations required to be performed for detection of potential service degradation. Effective and reliable inspection methods for CASS materials are essential to achieving the objectives of defense-in-depth. A complicating issue is the presence of thermal aging embrittlement, a known degradation mechanism that occurs in CASS NPP materials. Further, while not as yet reported in CASS, many unforeseen instances of cracking in safety-related piping system welds have been experienced in other austenitic materials. Currently, a performance-based method to qualify NDE in CASS is not available. Pacific Northwest National Laboratory (PNNL) has performed nondestructive examination (NDE) research under the sponsorship of the U.S. Nuclear Regulatory Commission (NRC) for over four decades. A primary objective of the research has been to assess the effectiveness and reliability of conventional and advanced NDE methods for the inspection of light-water reactor components. One of the tasks being performed within this framework is to evaluate state-of-the-art technical approaches for examining safety-related nuclear reactor components that pose significant challenges to traditional NDE methods. A specific area of research in this regard is the volumetric examination of coarse-grained weldments and base materials. This report summarizes, compiles, and assesses relevant investigations performed by PNNL and other domestic and international organizations for welds adjacent to CASS components to provide a comprehensive evaluation on this subject. The primary objectives of the report are to assess the overall feasibility for advanced NDE methods to reliably and effectively examine field CASS piping components and to determine if techniques similar to those described in existing standards could be applied to develop performance demonstration requirements for CASS piping components. This report discusses improving the reliability of CASS examinations through the use of advanced low-frequency phased-array techniques, coupled with other “best practice” examination parameters, and makes recommendations for consideration by NRC Staff regarding the development of effective performance-based qualifications for CASS weldments. In addition to the PNNL research documented here, over 230 historical and more recent publications have been reviewed in the development of this document. The report is expected to be a useful resource for engineers and scientists involved in NDE of CASS for purposes of inservice inspection on existing plants during current and extended periods of operation. Finally, researchers and NDE practitioners conducting future investigations to advance the state-of-the-art should find the information contained in this report to be beneficial.
36 MATERIALS SCIENCE↗
Crack Growth Rate and Large Plate Demonstration of Chloride-induced Stress Corrosion Cracking in Spent Nuclear Fuel Storage Canisters
This report describes the body of work involving testing and analyses performed in FY18 and FY19 at the Savannah River National Laboratory and at Korea University to determine chloride-induced stress corrosion crack (CISCC) growth rates in weldments of austenitic stainless steel plate material. The primary work involved: several separate crack growth rate test campaigns with new testing setups using laboratory-scale corrosion specimens; analyses to estimate the stress intensity factors for flaws postulated to be present in the residual stress fields of axial and circumferential weldments in a prototypic dry storage canister; and establishment of a “large plate” (approximately 51×46 cm with thickness 16 mm and weight about 30 kg) CISCC test that uses a plate with a circumferential weldment harvested from the Sandia National Laboratories’ full-size mockup dry storage canister. The tests for crack growth rate were conducted on ASTM E1861 bolt-load compact tension specimens in a setup designed to allow initially dried salt deposits to deliquesce and infuse the brine to the crack front under conditions relevant to the canister storage environments (e.g., temperature and humidity). The crack growth rate test results matched previous experimental data in the open literature. These literature data had been compiled by SNL and EPRI to develop a temperature-dependent (K-insensitive) crack growth rate model to support flaw disposition in the ASME Boiler and Pressure Vessel Section XI Code Case N-860, “Examination Requirements and Acceptance Standards for Spent Nuclear Fuel Storage and Transportation Containment Systems.” The knowledge of the salt, temperature, humidity conditions for CISCC including the threshold stress intensity factor, $K_{ISCC}$, were used to setup the large plate test in which a set of partthrough- wall and through-wall electrical discharge machined (EDM) defects were positioned in the weld residual stress field of the welded plate material from the mockup canister. A salt solution was applied to this plate specimen with an air-brush spray, then dried, and then exposed to a constant 75% RH condition at an ambient room temperature of 22 °C. The salt loading and environmental condition is expected to be aggressive to cause CISCC. The visual results at the surface of the plate show corrosion product staining (brown rust appearance) but with no CISCC emanating from the machined notches after approximately 5 months exposure to date. The plate test will continue in FY20 and phased-array ultrasonic testing and other NDE techniques will be applied to identify and characterize CISCC that may emanate from the machined defects. The notches and any CISCC from them will be sectioned at the conclusion of the test to verify NDE characterization, and to develop effective through-wall crack growth rates from cracks that would likely be branched.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Germanium Telluride Chalcogenide Switches for RF Applications
This project developed prototype germanium telluride switches, which can be used in RF applications to improve SWAP (size, weight, and power) and signal quality in RF systems. These switches can allow for highly reconfigurable systems, including antennas, communications, optical systems, phased arrays, and synthetic aperture radar, which all have high impact on current National Security goals for improved communication systems and communication technology supremacy. The final result of the project was the demonstration of germanium telluride RF switches, which could act as critical elements necessary for a single chip RF communication system that will demonstrate low SWAP and high reconfigurability
42 ENGINEERING↗
Welding of Haynes 282 to Steels to Enable Modular Rotors for Advanced Ultra Super-Critical Steam Turbines
Steam turbines for an Advanced Ultra Super Critical (AUSC) fossil fired power plant will operate at temperatures well above those of current commercial steam cycles with inlet temperatures more than 760 C , which is beyond the capabilities of alloy steels presently used for steam turbine applications and requires advanced materials. Large components such as steam turbine rotors may be made of nickel based super alloys such as Haynes 282 (H282). However, monolithic forgings of superalloys in the sizes required for large steam turbines rotors can be prohibitively expensive besides many technical challenges. To minimize cost and alleviate the related technical challenges, superalloy use needs to be limited to locations on the steam turbine rotor where strength and temperature requirements cannot be met by conventional steels. This is possible if nickel-based superalloys can be successfully welded to steels and the related technical challenges - machining parts made of dissimilar welded materials, non-destructive examination of such welds for flaw detection; and, material properties of such hybrid components – are sufficiently addressed. In this technology development project, we successfully welded H282 to plates up to ~ 75 mm (~ 3 inches) to a 3.5NiCrMoV steel of similar thickness. Advanced ultrasonic inspection technique called Phased Array Ultrasonic Testing (PAUT) was employed to examine the dissimilar H282-Steel welds, into which flat bottomed side drilled holes (SDH) of various diameters were introduced, to determine the minimum detectable feature sizes; it was shown that with PAUT SDH of dia. down to 0.5 mm could be detected in the base alloys and SDH with dia. down to 2.4 mm could be detected in the weld metal under multiple orientations successfully. An autonomous machining process monitoring system was developed and demonstrated whereby the forces acting on the cutting tool could be actively monitored as the cutting tool transitioned from H282 to Steel across the weld using which the machining parameters can be potentially altered without interruption to extend tool life. This project successfully achieved its objectives of - i. Developing a welding methodology and viable welding geometries, to successfully join H282 to steel 3.5CrMoNiV steel to enable manufacture of modular steam turbine rotors for AUSC applications (conditions of at least 760 °Celsius and 3,100 psia (pounds per square inch absolute pressure) and evaluate the material properties of the welded specimen. ii. Employ the advanced ultrasonic inspection technique to the dissimilar weld metal joint and determine the minimum detectable feature sizes. iii. Develop effective machining techniques to machine such hybrid structures with online tool force monitoring and effect machine state metrics for optimal results.
20 FOSSIL-FUELED POWER PLANTS↗
Meet the Lightslingers [Slides]
Electromagnetic applications such as Radar or telecommunications use decades-old technology: dipoles, dish/horn antennas, phased arrays.
42 ENGINEERING↗
Ultra-Low Power and Low-Cost Chips to Supercharge the High-Performance Antennas of the Future (CRADA Final Report)
As part of the Cyclotron Road program, the Oso Semiconductor project team investigated technological solutions to address the high cost and power consumption of phased array antennas. The power and cost for these antennas are greatly limiting growth for several high-impact wireless applications, such as: 5G, satellite communication, and radar sensing.
42 ENGINEERING↗
A VIPA Spectrograph with Ultra-high Resolution and Wavelength Calibration for Astronomical Applications
A prototype spectrograph using a Virtually Imaged Phased Array (VIPA) as the main dispersion element is presented, and its performance is fully examined in our laboratory. The single-mode, fiber-fed spectrograph with simultaneous wavelength calibration possesses a spectral resolution well in excess of R≈1.12×10{sup 6} while the size of the VIPA is several orders of magnitude smaller than that of a conventional échelle with comparable resolution. In laboratory tests, the VIPA-based instrument with a homemade Yb:fiber ring laser frequency comb demonstrates a mode-to-mode tracking stability of 41 cm s{sup −1} over a period of 6 hr. The VIPA spectrograph has promising applications in various astronomical observations in which ultra-high resolution and calibration precision are imperative, such as solar physics research, exoplanet searching with the radial velocity method, and O{sub 2} detection in the atmosphere of Earth-like planets. Ultimately, feasible optimizations for night-sky observations under seeing limited conditions are discussed.
79 ASTRONOMY AND ASTROPHYSICS↗
ATS-4 study program, volume 6 Final report
Parabolic antenna feed, phased array, and communications equipment of Applications Technology Satellite /ATS/
APPLICATIONS TECHNOLOGY SATELLITE /ATS/↗
Combined acquisition and tracking radar. A parametric study Final technical report
Design parameters for developing phased array acquisition and tracking radar for onboard experiment in Apollo spacecraft
Source record↗
High-speed, medium-power, solid-state diode driver.
Transistor circuit driving S-band diode digital shifters for phased array antenna
Graf, E. R.↗
Characteristics of step-recovery-diode frequency multipliers
Investigation into the uses of step-recovery diodes /SRD's/ leads to the development of necessary circuitry for using fast current-switching capabilities of SRD's in frequency multiplication, the design of solid-state X-band transmitters employing SRD multipliers, and the use of SRD multipliers in a phased-array receiving antenna.
Source record↗
Space base antenna study
The field of view required of the space base antenna is defined for both the tracking and data relay satellite link and detached module links. The gain requirements are established and the feasibility of alternative antenna configurations using phased arrays and reflectors are considered. One recommended and one alternative configuration are presented for each of the required links.
Deerkoski, L. F.↗
A radar altimeter-driftmeter for small planetary probes
A light weight radar altimeter-driftmeter applicable to landing planetary probes is described. The system utilizes a small light weight phased array antenna to generate three independent radio frequency beams. The range and Doppler along each of these beams is measured. The six measured quantitites are then combined with a resulting range (altitude) accuracy of 75 meters and a horizontal drift velocity accuracy of 6 cm/sec. The entire system weighs less than 3.7 kilograms and requires less than 9 watts of dc power.
Bryan, J. W.↗
Investigation of L-band shipboard antennas for maritime satellite applications
A basic conceptual investigation of low cost L-band antenna subsystems for shipboard use was conducted by identifying the various pertinent design trade-offs and related performance characteristics peculiar to the civilian maritime application, and by comparing alternate approaches for their simplicity and general suitability. The study was not directed at a single specific proposal, but was intended to be parametric in nature. Antenna system concepts were to be investigated for a range of gain of 3 to 18 dB, with a value of about 10 dB considered as a baseline reference. As the primary source of potential complexity in shipboard antennas, which have beamwidths less than hemispherical as the beam pointing or selecting mechanism, major emphasis was directed at this aspect. Three categories of antenna system concepts were identified: (1) mechanically pointed, single-beam antennas; (2) fixed antennas with switched-beams; and (3) electronically-steered phased arrays. It is recommended that an L-band short backfire antenna subsystem, including a two-axis motor driven gimbal mount, and necessary single channel monopulse tracking receiver portions be developed for demonstration of performance and subsystem simplicity.
Heckert, G. P.↗
Laser power stations in orbit.
Potential laser applications for space-borne power generation are discussed in the light of the current state of the art. The feasible ranges of various laser classes with standing waves are estimated. Power and efficiency, mirror factors, phased-array performance and beam patterns are analyzed as selection characteristics. Other topics include the maximum receiving-element size, energy conversion, pointing and tracking, causes of deformation, and mirror distortions. It is theorized that a nuclear-fueled laser satellite could beam power to distances twice the earth-sun distance with predictable pointing accuracies.
Hansen, C. F.↗
Microstrip antennas
It is possible to design and construct simple, efficient microwave antenna, either linearly or circularly polarized, which should be useful in phased arrays. Mounted on thin dielectric substrate, it extends slightly above ground plane. Space behind ground plane is required for feed line and mounting hardware.
Howell, J. Q.↗
Aspects of investigating STOL noise using large-scale wind-tunnel models.
The applicability of the NASA Ames 40- by 80-foot wind tunnel for acoustic research on STOL concepts has been investigated. The acoustic characteristics of the wind-tunnel test section have been studied with calibrated acoustic sources. Acoustic characteristics of several large-scale STOL models have been studied in both the free-field and wind-tunnel acoustic environments. The results of these studies indicate that the acoustic characteristics of large-scale STOL models can be measured in the wind tunnel if the test section acoustic environment and model acoustic similitude are taken into consideration. The reverberant field of the test section must be determined with an acoustically similar noise source. A directional microphone, a phased array of microphones, and extrapolation of near-field data to far-field are some of the techniques being explored as possible solutions to the directivity loss in a reverberant field. The model sound pressure levels must be of sufficient magnitude to be distinguishible from the wind-tunnel background noise.
Falarski, M. D.↗