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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 1,369 records · Page 76
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Compact, Efficient, Low-cost Lasers (CELL) Project (Final Report)

Development of clean, sustainable and affordable energy sources is a national and international challenge. Inertial Fusion Energy (IFE) may provide a transformational solution that is scalable, proliferation-resistant, and that generates negligible nuclear waste. To produce energy economically competitive with alternative power plants, the IFE laser drive must operate at a high repetition rate (≥10 Hz) with high efficiency (>10%), while maintaining beam quality suitable for focusing to a small spot suitable for compressing the fusion target. The NIF laser system meets the beam quality requirements using a solid-state gain medium pumped by flashlamps. Scaling from NIF to IFE requires increases of ~10 5 in rep rate and ~20X in efficiency, which adds significant challenges to the laser design. The increased repetition rate results in much more waste heat generated in the system, and the prevention of thermal beam quality degradation (through phenomena such as thermally-induced birefringence) becomes a critical issue. While thermal issues are mitigated by increasing the system volume, a major size increase renders the system less economical and less easy to site. LIFE laser efficiency targets can be achieved at high rep rate without reliability degradation by using diode lasers as pumps. An IFE plant requires ~10 8 diode laser bars. At current costs the diodes dominate the overall laser cost and render IFE less cost-effective. Thus, designing a compact and cost-effective laser system with the repetition rate, efficiency, and beam quality required for IFE presents a significant technical challenge. The goal of the CELL strategic initiative was to develop new laser architectures to address these challenges by leveraging recent advances in optical technology. New laser design options have become potentially feasible due to improvements in laser gain media, diode pumps, large aperture nonlinear optics, and damage-resistant optics that have occurred since NIF’s conception. The project investigated designs that take advantage of these advances, combining them with advanced and novel subsystem concepts to achieve laser designs with significantly improved performance, size, and cost.

42 ENGINEERING↗
DOE OSTI2012

Comparing Linear Microinstability of the National Compact Stellarator Expriment and a Shaped Tokamak

One metric for comparing con nement properties of di erent magnetic fusion energy con gurations is the linear critical gradient of drift wave modes. The critical gradient scale length determines the ratio of the core to pedestal temperature when a plasma is limited to marginal stability in the plasma core. The gyrokinetic turbulence code GS2 was used to calculate critical temperature gradients for the linear, collisionless ion tem- perature gradient (ITG) mode in the National Compact Stellarator Experiment (NCSX) and a prototypical shaped tokamak, based on the pro les of a JET H-mode shot and the stronger shaping of ARIES-AT. While a concern was that the narrow cross section of NCSX at some toroidal locations would result in steep gradients that drive instabilities more easily, it is found that other stabilizing e ects of the stellarator con guration o set this so that the normalized critical gradients for NCSX are competitive with or even better than for the tokamak. For the adiabatic ITG mode, NCSX and the tokamak had similar critical gradients, though beyond marginal stability, NCSX had larger growth rates. However, for the kinetic ITG mode, NCSX had a higher critical gradient and lower growth rates until a/LT ≈ 1:5 a/LT;crit, when it surpassed the tokamak's. A discussion of the results presented with respect to a/LT vs R/LT is included.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2012

Two-Piece Compaction Die Design

ORNL/TM-2010/48 described some results from using the finite element program ANSYS to determine the design geometry for compaction dies used to create europium oxide and tantalum control plates. Because of some discrepancies between the final drawings of the parts and the TM analyses, the models were reworked and some design modifications were made. When the mesh density was increased, increasing the number of elements in the model, especially near the corners, the maximum stresses in the corners were found to be higher than in the previous study. The dies needed to be designed with inner corner radii and interference fits that would allow the necessary compression force to create the plates but not exceed the yield strength of the material. Also, modeling was done to determine the effects of loading the dies asymmetrically in the axial direction, as this would make the plate extraction process easier while increasing the stress in the corners. The results show that for the tantalum die, a diametrical interference fit of 0.0020 in. between the outer ring and the insert is acceptable, and the inner corner radius can be as small as 0.0035 in. The insert has an outer diameter of 6.150 in. The cavity in the insert is 3.4640 $\times$ 0.8086 ± 0.002 in. and the outer ring has an outer diameter of 8.150 in. The die is 2.960 in. deep. With these design parameters, the plate can be formed so that its edge is 0.500 in. from the top or the bottom of the die, and the maximum stress everywhere in the die will be less than the yield strength of the materials. For the europium oxide die, the diametrical interference fit between the outer ring and the insert must be between 0.0075 and 0.0080 in. The inner corner radius can be as small as 0.0055 in. The insert has an outer diameter of 5.960 in. The cavity in the insert is 3.4552 $\times$ 1.7246 ± 0.002 in. and the outer ring has an outer diameter of 8.150 in. The die is 3.020 in. deep. With these design parameters, the plate can be formed so that its edge is 1.225 in. from the top or the bottom of the die.

42 ENGINEERING↗
DOE OSTI2013

Development of Compact Gamma Camera for Detection of Prostate Carcinoma

BNL and Hybridyne will jointly develop a compact gamma camera capable of localizing cancerous tumors within the prostate gland. The new gamma-ray camera will consist of a pixilated cadmium-zinc-telluride (CZT) detector array, which would be flip-chip bonded to a suitable substrate. Application specific integrated circuits would also be developed to read out the electronic signals from the pixels, and the detector/ASIC would be integrated into a small probe capable of imaging shaped radioactive phantoms to simulate the detection of cancerous tumors within the prostate gland.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2014

A Compact, Backscattering Deplolarization Cloud Spectrometer for Ice and Water Discrimination

This project was to develop a compact optical particle spectrometer, small enough for operation on UAVS, that measures the optical diameter of cloud hydrometeors and differentiates their water phase (liquid or solid). To reach this goal, a work plan was laid out that would complete three objectives: 1) Evaluation of designs for an optical particle spectrometer that measures the component of light backscattered at two polarization angles. 2) Testing of selected designs on an optical bench. 3) Construction and preliminary testing of a prototype instrument based on the selected, optimum design. A prototype instrument was developed and tested in an icing wind tunnel where the results showed good measurement of cloud droplets and ice particles.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Implementation and Optimization of miniGMG - a Compact Geometric Multigrid Benchmark

Multigrid methods are widely used to accelerate the convergence of iterative solvers for linear systems used in a number of different application areas. In this report, we describe miniGMG, our compact geometric multigrid benchmark designed to proxy the multigrid solves found in AMR applications. We explore optimization techniques for geometric multigrid on existing and emerging multicore systems including the Opteron-based Cray XE6, Intel Sandy Bridge and Nehalem-based Infiniband clusters, as well as manycore-based architectures including NVIDIA's Fermi and Kepler GPUs and Intel's Knights Corner (KNC) co-processor. This report examines a variety of novel techniques including communication-aggregation, threaded wavefront-based DRAM communication-avoiding, dynamic threading decisions, SIMDization, and fusion of operators. We quantify performance through each phase of the V-cycle for both single-node and distributed-memory experiments and provide detailed analysis for each class of optimization. Results show our optimizations yield significant speedups across a variety of subdomain sizes while simultaneously demonstrating the potential of multi- and manycore processors to dramatically accelerate single-node performance. However, our analysis also indicates that improvements in networks and communication will be essential to reap the potential of manycore processors in large-scale multigrid calculations.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2014

Photocopia-A Unibody Mono-material Compact and Scalable Photomultiplier

The Photocopia photomultiplier tube (PMT) takes advantage of two of the many unique properties of the hydrogenated amorphous silicon-germanium (a-SiGe) photoemitter material: its mechanical flexibility and mostly substrate-independent properties. The a-SiGe photoemitter has high secondary electron (SE) yield. It can be used both as the photocathode and as the gain medium. The active material can be grown on a flat, thin unibody substrate, formed and then “rolled up” ex situ. The completed structure would then be activated and sealed within a tube. The Ge component can be increased to enhance red-sensitivity. Compact sizes are possible, minimizing magnetic field effects. The Photocopia PMT will be a low cost alternative to MCPs for TOF detectors and provide better timing discrimination for Cherenkov detectors. Retention of the ability to activate to a normal photoyield state upon flexing (bending) the substrate of the a-SiGe material after growth, but prior to activation has been shown. The SE coefficient of the activated material has been characterized over the voltage range suitable for utilization as the gain material. The time response of the material is suited to PMT use.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Compact Neutron HBT Model Notes and Comments

This writeup is intended to address some questions about the compact model for neutron effects in HBT's that came up during the QASPR independent review.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Safety testing of AGR-2 UO 2 compacts 3-3-2 and 3-4-2

Post-irradiation examination (PIE) is in progress on tristructural-isotropic (TRISO) coated-particle fuel compacts from the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program second irradiation experiment (AGR-2) [Collin 2014]. The AGR-2 PIE will build upon new information and understanding acquired throughout the recently-concluded six-year AGR-1 PIE campaign [Demkowicz et al. 2015] and establish a database for the different AGR-2 fuel designs.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2015

SimTrack: A compact c++ library for particle orbit and spin tracking in accelerators

SimTrack is a compact c++ library of 6-d symplectic element-by-element particle tracking in accelerators originally designed for head-on beam-beam compensation simulation studies in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It provides a 6-d symplectic orbit tracking with the 4th order symplectic integration for magnet elements and the 6-d symplectic synchro-beam map for beam-beam interaction. Since its inception in 2009, SimTrack has been intensively used for dynamic aperture calculations with beam-beam interaction for RHIC. Recently, proton spin tracking and electron energy loss due to synchrotron radiation were added. In this article, I will present the code architecture, physics models, and some selected examples of its applications to RHIC and a future electron-ion collider design eRHIC.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Additive Manufacturing for Cost Efficient Production of Compact Ceramic Heat Exchangers and Recuperators

An additive manufacture technique known as laminated object manufacturing (LOM) was used to fabricate compact ceramic heat exchanger prototypes. LOM uses precision CO2 laser cutting of ceramic green tapes, which are then precision stacked to build a 3D object with fine internal features. Modeling was used to develop prototype designs and predict the thermal response, stress, and efficiency in the ceramic heat exchangers. Build testing and materials analyses were used to provide feedback for the design selection. During this development process, laminated object manufacturing protocols were established. This included laser optimization, strategies for fine feature integrity, lamination fluid control, green handling, and firing profile. Three full size prototypes were fabricated using two different designs. One prototype was selected for performance testing. During testing, cross talk leakage prevented the application of a high pressure differential, however, the prototype was successful at withstanding the high temperature operating conditions (1300 °F). In addition, analysis showed that the bulk of the part did not have cracks or leakage issues. This led to the development of a module method for next generation LOM heat exchangers. A scale-up cost analysis showed that given a purpose built LOM system, these ceramic heat exchangers would be affordable for the applications.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2016

System Construction of the Stilbene Compact Neutron Scatter Camera

This report documents the construction of a stilbene-crystal-based compact neutron scatter camera. This system is essentially identical to the MINER (Mobile Imager of Neutrons for Emergency Responders) system previously built and deployed under DNN R&D funding,1 but with the liquid scintillator in the detection cells replaced by stilbene crystals. The availability of these two systems for side-by-side performance comparisons will enable us to unambiguously identify the performance enhancements provided by the stilbene crystals, which have only recently become commercially available in the large size required (3” diameter, 3” deep).

36 MATERIALS SCIENCE↗
DOE OSTI2016

Compact Ceramic Microchannel Heat Exchangers

The objective of the proposed work was to demonstrate the feasibility of a step change in power plant efficiency at a commercially viable cost, by obtaining performance data for prototype, compact, ceramic microchannel heat exchangers. By performing the tasks described in the initial proposal, all of the milestones were met. The work performed will advance the technology from Technology Readiness Level 3 (TRL 3) to Technology Readiness Level 4 (TRL 4) and validate the potential of using these heat exchangers for enabling high efficiency solid oxide fuel cell (SOFC) or high-temperature turbine-based power plants. The attached report will describe how this objective was met. In collaboration with The Colorado School of Mines (CSM), specifications were developed for a high temperature heat exchanger for three commercial microturbines. Microturbines were selected because they are a more mature commercial technology than SOFC, they are a low-volume and high-value target for market entry of high-temperature heat exchangers, and they are essentially scaled-down versions of turbines used in utility-scale power plants. Using these specifications, microchannel dimensions were selected to meet the performance requirements. Ceramic plates were fabricated with microchannels of these dimensions. The plates were tested at room temperature and elevated temperature. Plates were joined together to make modular, heat exchanger stacks that were tested at a variety of temperatures and flow rates. Although gas flow rates equivalent to those in microturbines could not be achieved in the laboratory environment, the results showed expected efficiencies, robust operation under significant temperature gradients at high temperature, and the ability to cycle the stacks. Details of the methods and results are presented in this final report.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2017

Development of Mini-Compact Tension Test Method for Determining Fracture Toughness Master Curves for Reactor Pressure Vessel Steels

Small specimens are playing the key role in evaluating properties of irradiated materials. The use of small specimens provides several advantages. Typically, only a small volume of material can be irradiated in a reactor at desirable conditions in terms of temperature, neutron flux, and neutron dose. A small volume of irradiated material may also allow for easier handling of specimens. Smaller specimens reduce the amount of radioactive material, minimizing personnel exposures and waste disposal. However, use of small specimens imposes a variety of challenges as well. These challenges are associated with proper accounting for size effects and transferability of small specimen data to the real structures of interest. Any fracture toughness specimen that can be made out of the broken halves of standard Charpy specimens may have exceptional utility for evaluation of reactor pressure vessels (RPVs) since it would allow one to determine and monitor directly actual fracture toughness instead of requiring indirect predictions using correlations established with impact data. The Charpy V-notch specimen is the most commonly used specimen geometry in surveillance programs. Validation of the mini compact tension specimen (mini-CT) geometry has been performed on previously well characterized Midland beltline Linde 80 (WF-70) weld in the unirradiated condition. It was shown that the fracture toughness transition temperature, To, measured by these Mini-CT specimens is almost the same as To value that was derived from various larger fracture toughness specimens. Moreover, an International collaborative program has been established to extend the assessment and validation efforts to irradiated Linde 80 weld metal. The program is underway and involves the Oak Ridge National Laboratory (ORNL), Central Research Institute for Electrical Power Industry (CRIEPI), and Electric Power Research Institute (EPRI). The irradiated Mini-CT specimens from broken halves of previously tested Charpy specimens of Midland beltline weld have been machined and just arrived to ORNL as part of this international collaboration. The ORNL will initiate tests of the irradiated Linde 80 weld in FY2017 and results of this international program will be reported in FY2018.

42 ENGINEERING↗
DOE OSTI2017

Compact Nanoparticle Size Distribution Measurement System for Unmanned Aerial Systems (UAS)

Brechtel Manufacturing Incorporated (BMI) is developing a compact, nanoparticle sizer optimized for use on Unmanned Aerial Vehicles (UAVs) and other applications where space, weight, power and cost are significant barriers to deployment. The instrument will allow observations of size-resolved aerosol number concentration (0.005 < D p < 0.3 μm, D p is particle diameter). The new development helps address the need for reduced uncertainties in atmospheric radiative transfer and weather prediction model sensitivities to ambient aerosol properties by promoting the capability to perform aerosol measurements more often, in more locations, and at reduced cost. Applications of the new technology include vertical atmospheric profiling with UAVs, balloons and other mobile platforms to constrain weather forecast models, long-term air quality measurements, aerosol health effects studies, and routine monitoring of ambient aerosol properties in urban air sheds.

47 OTHER INSTRUMENTATION↗
DOE OSTI2017

Safety Testing of AGR-2 UCO Compacts 6-4-2 and 2-3-1

Post-irradiation examination (PIE) and elevated-temperature safety testing are being performed on tristructural-isotropic (TRISO) coated-particle fuel compacts from the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program second irradiation experiment (AGR-2). Details on this irradiation experiment have been previously reported [Collin 2014]. The AGR-2 PIE effort builds upon the understanding acquired throughout the AGR-1 PIE campaign [Demkowicz et al. 2015] and is establishing a database for the different AGR-2 fuel designs.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

Compact Models for Defect Diffusivity in Semiconductor Alloys.

Predicting transient effects caused by short - pulse neutron irradiation of electronic devices is an important part of Sandia's mission. For example , predicting the diffusion of radiation - induced point defects is needed with in Sandia's Qualification Alternative to the Sandia Pulsed Reactor (QASPR) pro gram since defect diffusion mediates transient gain recovery in QASPR electronic devices. Recently, the semiconductors used to fabricate radiation - hard electronic devices have begun to shift from silicon to III - V compounds such as GaAs, InAs , GaP and InP . An advantage of this shift is that it allows engineers to optimize the radiation hardness of electronic devices by using alloy s such as InGaAs and InGaP . However, the computer codes currently being used to simulate transient radiation effects in QASP R devices will need to be modified since they presume that defect properties (charge states, energy levels, and diffusivities) in these alloys do not change with time. This is not realistic since the energy and properties of a defect depend on the types of atoms near it and , therefore, on its location in the alloy. In particular, radiation - induced defects are created at nearly random locations in an alloy and the distribution of their local environments - and thus their energies and properties - evolves with time as the defects diffuse through the alloy . To incorporate these consequential effects into computer codes used to simulate transient radiation effects, we have developed procedures to accurately compute the time dependence of defect energies and properties and then formulate them within compact models that can be employed in these computer codes. In this document, we demonstrate these procedures for the case of the highly mobile P interstitial (I P ) in an InGaP alloy. Further dissemination only as authorized to U.S. Government agencies and their contractors; other requests shall be approved by the originating facility or higher DOE programmatic authority.

36 MATERIALS SCIENCE↗