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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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Outcomes of WPEC SG47 on "Use of Shielding Integral Benchmark Archive and Database for Nuclear Data Validation"

The Working Party on International Nuclear Data Evaluation Co-operation Subgroup 47 (WPECSG47) entitled "Use of Shielding Integral Benchmark Archive and Database for Nuclear Data Validation" was organised from 2019 and 2022 with the objectives to promote more systematic and wider use of shielding benchmark experiments in nuclear data (ND) and transport code validation and development, to provide feedback on the Shielding Integral Benchmark Archive and Database (SINBAD), and to promote its further development in coordination with the Expert Group on Physics of Reactor Systems (EGPRS). Altogether 9 meetings, the large majority (8) held remotely, were organised during the past 3 years to discuss the experience on the use of SINBAD, evaluation of new benchmarks and improvements to be contributed to the database which was severely neglected and lacking maintenance over the past ← 10+ years. Several proposals for new or updated benchmark evaluation were presented and discussed, such as FNG copper, LLNL pulsed spheres, CIAE iron sphere, KFK 1977 gamma measurements, Rez Fe sphere, ASPIS, ORNL Oxygen broomstick, TIARA and others. Complementing the database with new features was also discussed, for example providing the nuclear data sensitivity profiles more systematically would facilitate and better guide the use of data. Information on the geometry, (radiation source) and materials available in CAD format is expected to allow an easier and less error prone reference for computational model preparation and a potential input to CAD based workflows. Inputs for various transport codes and other benchmark data from participants have been shared via the NEA GitLab which could hopefully in the future evolve and form a bases for critically checked and validated benchmark data. Future development of SINBAD will be monitored by EGPRS and the newly created SINBAD Task Force.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Shielded magnetic small-angle neutron scattering for characterization of radioactive samples

The development of a Pb-shielded fixture for the execution of a small-angle neutron scattering (SANS)-based workflow for interrogation of highly irradiated nuclear materials has been explored. The Pb shielding was specially designed to reduce the detected radioactivity from the specimen during SANS experiments, and the overall configuration is termed shielded magnetic SANS (SM-SANS). Two FeCrAl-based alloys, C35M and 125YF, were examined with the SM-SANS technique using a free-form size distribution locally monodisperse model in both the as-received and irradiated states. Quantitative values derived from the free-form size distribution were compared with atom probe tomography experiments. Microstructural and compositional parameters determined using the two characterization techniques were complements of each other. The results demonstrate that the SM-SANS technique is an effective means of characterizing nanoscale clustering in irradiated material systems and provides new avenues for investigating radioactive material microstructures.

FeCrAl↗
DOE OSTI2020

Electromagnetic Shielding Design for 200 kW Stationary Wireless Charging of Light-Duty EV

Wireless power transfer (WPT) is a developing technology with the advantage of convenience and flexible charging. SAE recommended practice J2954 defines typical size and geometry with aluminum or ferrite plate shielding to limit leakage electromagnetic (EM) fields for WPT with power levels lower than 22 kVA from the input side. However, as the WPT power goes up to 100- or 200-kW level, EM safety surrounding the WPT becomes a critical concern. To address this oncoming safety challenge, a novel ferrite shielding design is proposed in this paper. Different misalignment scenarios in accordance with definitions in SAE J2954 are also taken into consideration to ensure EM safety under various operation scenarios. Simulation results, which are preliminarily verified by magnetic field measurements at 1.1 m from the center of the vehicle side coil under 100 kW operation, indicate that the magnetic field leakage can be maintained below the limits defined in SAE J2954 for 200 kW operation. A 3.3 kW scale-down test was also carried out and compared to parallel scale-down simulations. 26.8% field emission reduction is observed from the scale-down test, which supports the effectiveness of the proposed shielding design.

Zhang, Bo↗
DOE OSTI2024

Effects on Structure’s Electromagnetic Shielding Effectiveness Considering Penetrating Cables Coupling Energy from HEMP Event

The threat of weaponized electromagnetic pulse (EMP) is a serious factor in defining power system resilience. Without adequate knowledge regarding the interaction between EMP and power system infrastructure, system personnel may be unable to plan for and operate during an EMP event and major blackouts could occur. This work studies the interaction between EMP and structures, specifically analyzing the shielding effectiveness of buildings emulating power generation facilities. The main focus is to determine how penetrating cables affect the structure’s shielding effectiveness. Several cable parameters including height above ground, radius, termination configuration, and length are analyzed via computational electromagnetic simulations. Results demonstrated penetrating cables can significantly diminish a structure’s shielding effectiveness, especially the electric field. Length of cable is the most influential parameter.

Mignardot, David↗
DOE OSTI2024

Performance of three hydrophone flow shields in a tidal channel

Pseudosound caused by turbulent pressure fluctuations in fluid flow past a hydrophone, referred to as flow noise, can mask propagating sounds of interest. Flow shields can mitigate flow noise by reducing non-acoustic pressure fluctuations sensed by a hydrophone. We evaluate the performance of three hydrophone flow shields (two nylon fabrics and an oil-filled enclosure) in a tidal channel with peak current speed of 1.3 m s−1. All three flow shields reduced flow noise without attenuating propagating sound below 20 kHz. The oil-filled enclosure performed best, reducing flow noise by over 30 dB at frequencies below 40 Hz.

47 OTHER INSTRUMENTATION↗
DOE OSTI2025

AmeriFlux FLUXNET-1F US-EA6 Camp Wood Shield Ranch Oak Savannah

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-EA6 Camp Wood Shield Ranch Oak Savannah. This is the FLUXNET version of the carbon flux data for the site US-EA6 Camp Wood Shield Ranch Oak Savannah produced by applying the standard ONEFlux (1F) software. Site Description - This tower is located on the Shield Ranch, approximately 5 km southeast of Camp Wood, TX. The tower consists of a permanent structure located on a flat creek terrace between stands of oak trees.

Fleck, Preston [The University of Texas at Austin,↗
DOE OSTI2020

Characterizing Shielded Special Nuclear Material by Neutron Capture Gamma-Ray Multiplicity Counting

We present a new neutron multiplicity counting analysis and measurement method for neutron-shielded fissile material using neutron-capture gamma rays. Neutrons absorbed in shielding produce characteristic gamma rays that preserve the otherwise lost neutron multiplicity signature. Neutron multiplicity counting provides estimates of fission parameters, such as neutron leakage multiplication, spontaneous fissioner (e.g. Pu-240) mass, and (α,n) ratio. Standard neutron multiplicity counting can incorporate the new neutron-capture gamma-ray multiplicity counting technique to characterize previously degenerate or intractable source configurations by maximizing the multiplicity signature. The new method decouples neutron source-detector interferences, such as reflection and thermalization time in the detector, that could improve measurements of the mean neutron lifetime. We also develop a detector prototype for the multiplicity counting of neutron-capture gamma rays and present detector design considerations, such as detection material and shielding, to optimize the detection of the 2.2 MeV hydrogen capture gamma ray. We simulate the prototype neutron- capture gamma-ray multiplicity counter against the BeRP ball in polyethylene shells to inform future measurements.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

E-PiPEline: Face Shields and Face Coverings Using Commonly Available Materials

The Center for Disease Control has recommended that the public should wear cloth face coverings in public settings . Face coverings and face shields can be made by using Commonly Available Materials (CAMs). As part of the Sandia COVID - 19 LDRD effort (funded under the Materials Science Investment Area), the Sandia E - PiPEline task evaluated design options for face coverings and face shields considering their effectiveness, durability, build difficulty, build cost, and comfort. Observations from this investigation are presented here to provide guidelines for home construction of face coverings and face shields

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Thermal / structural analysis of the HB 650 thermal shield

Fermilab’s PIP-II project’s superconducting linear accelerator will drive the next generation of particle accelerators through a revolution in beam intensity. Key to beam intensification are the high efficiencies of niobium-tin superconducting radiofrequency (SRF) cavities operating at cryogenic temperatures near 5 Kelvin. A multifaceted approach is employed to achieve and maintain the extreme temperature. Vacuum provides the first barrier to thermal convection. Physical thermal intercept zones further isolate the exterior shell vacuum vessel at 300 Kelvin from the supercooled beamline. The first thermal intercept lies just inside the exterior vacuum vessel forming the 40 Kelvin zone. This 40K thermal shield is the focus of this investigation. In preparation for operation, the thermal shield is cooled from 300K to 40K in a slow process over 2-1/2 days. The factors limiting the cooling rate are a high thermal gradient which produces thermal strain and high mechanical stress. D ecreasing the time required to reach operational temperatures is the desired research goal. Physical testing data and finite element method (FEM) computer models from the Single Spoke Resonator – 1 (SSR1) and Linac Coherent Light Source (LCLS-II) cryomodules will be evaluated to determine needed design changes. The thermal shield design for the High Beta 650 MHz (HB650) will be modified and analyzed using FEM computer models to determine maximum cooling rate with a target of 50 thermal cycles of life. Maximum allowable stress will be determined through low cycle fatigue calculations.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Radiation Shielding Analysis of Niowave’s Uranium Target Assembly 2 (UTA-2) Facility for Molybdenum-99 Production

Niowave is seeking to develop a commercial medical isotope production process using a low-enriched uranium accelerator-driven subcritical reactor (ADSR) system to produce molybdenum-99. As part of the US Department of Energy national laboratory support to develop low enriched uranium molybdenum-99 production technologies, Oak Ridge National Laboratory is providing research and development resources to assist Niowave in the design and licensing process of its technology. The goals of this work under the radiation shielding task are to assist Niowave in developing a methodology and framework for efficient radiation shielding simulations of their Uranium Target Assembly 2 facility and to provide preliminary radiation shielding calculations and design recommendations for the facility.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2022

RFQ Beam Loss and Shielding Consideration

The proposed novel RFQ-based injector for LANSCE operation includes two independent low energy transports merging beams at the entrance of a single RFQ, which accelerates simultaneously both protons and H- ions with multiple flavors of the beams. One of the design issues of the project is the estimation of shielding requirements for the injector. Continuous access to the injector components reduces the number of times required to open the linac tunnel and saves time for the operation. Estimation involves the evaluation of radiation generated by beam losses in the injector. In this paper, we present an overview of the shielding in existing RFQ injectors and discuss the aspects of shielding configuration for the LANSCE RFQ-based injector.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Eddy Current Shielding of the Magnetic Field Ripple in the EIC Electron Storage Ring Vacuum Chambers

The EIC electron storage ring (ESR) has very tight tolerances for the beam position and size stability at the interaction point. The oscillations at the proton betatron frequency and its harmonics are the most dangerous because, for instance, they could lead to unacceptable proton emittance growth from the oscillating beam-beam kick from the electrons at the amplitude of the positional oscillations as low as 10 -4 of the beam size. Even at much lower frequencies, down to the single Hz range, the position oscillations at a few percent level of the nominal beam size were found to be dangerous. These oscillations could have different causes including magnet power supply ripple, mag net vibration, noise in the main and crab RF systems, and some collective instabilities. To specify the acceptable level of the current ripple and noise of the magnet power supplies we need to accurately account for the eddy current shielding by the vacuum chamber, as well as, potentially, by the laminated magnet yokes (considered elsewhere). With some ap proximations, the chamber shielding can be described analytically. The main objective of this note is to derive these analytical expressions and to document the resulting shielding performance of the ESR chamber.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Shielding Thickness Recommendations for an Activated Target Segment Vertical Stave

This analysis examines the shielding requirements needed to plan maintenance and handling operations of the target segment assembly vertical stave. It provides the analyses and results that fulfill the requirements of Task Order TO-150. The vertical stave is a stainless-steel welded assembly that carries cooling water to and from the target block. In this report, we characterize the dose rates and shielding requirements for the vertical stave only, i.e., separated from the target block. Shielding and dose rates for the target block only have been calculated in response to TO-008.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2024

Impact of Self-shielding Minihalos on the Lyα Forest at High Redshift

Abstract Dense gas in minihalos with masses of 10 6 −10 8 M ⊙ can shield themselves from reionization for ∼100 Myr after being exposed to the UV background. These self-shielded systems, often unresolved in cosmological simulations, can introduce strong absorption in quasar spectra. This paper is the first systematic study on the impact of these systems on the Ly α forest. We first derive the H i column density profile of photoevaporating minihalos by conducting 1D radiation–hydrodynamics simulations. We utilize these results to estimate the Ly α opacity from minihalos in a large-scale simulation that cannot resolve self-shielding. When the ionization rate of the background radiation is 0.03 × 10 −12 s −1 , as expected near the end of reionization at z ∼ 5.5, we find that the incidence rate of damped Ly α absorbers increases by a factor of ∼2−4 compared to at z = 4.5. The Ly α flux is, on average, suppressed by ∼3% of its mean due to minihalos. The absorption features enhance the 1D power spectrum up to ∼5% at k ∼ 0.1 h Mpc −1 (or 10 −3 km −1 s), which is comparable to the enhancement caused by inhomogeneous reionization. The flux is particularly suppressed in the vicinity of large halos along the line-of-sight direction at separations of up to 10 h −1 Mpc at r ⊥ ≲ 2 h −1 Mpc. However, these effects become much smaller for higher ionizing rates (≳0.3 × 10 −12 s −1 ) expected in the post-reionization Universe. Our findings highlight the need to consider minihalo absorption when interpreting the Ly α forest at z ≳ 5.5. Moreover, the sensitivity of these quantities to the ionizing background intensity can be exploited to constrain the intensity itself.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1965

Refractory metal shielding /insulation/ increases operating range of induction furnace

Thermal radiation shield contains escaping heat from an induction furnace. The shield consists of a sheet of refractory metal foil and a loosely packed mat of refractory metal fibers in a concentric pattern. This shielding technique can be used for high temperature ovens, high temperature fluid lines, and chemical reaction vessels.

Ebihara, B. T.↗
NASA NTRS1965

Shrinkable sleeve eliminates shielding gap in RF cable

RF shielding gap between an RF cable and a multipin connector is eliminated by a sleeve assembly installed between the connector and the terminated portion of the shielding. The assembly is enclosed in a heat-shrinkable plastic sleeve which completes the continuous RF shield.

Source record↗
NASA NTRS1968

Study of Plasma Radiation Shielding

The Plasma Radiation Shield is an active device using free electrons, electric and magnetic fields for the purpose of shielding astronauts from energetic solar flare-produced protons. The concept of Plasma Radiation Shielding is reviewed in the light of current studies. The available evidence indicates that the concept is physically sound, but important practical questions remain in at least two areas: these have to do with establishment and control of the extremely high voltages required, and with integration of the concept into a realistic space vehicle design.

Source record↗