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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 1,549 records · Page 86
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Fresnel zone plate development for x-ray radiography of hydrodynamic instabilities at the National Ignition Facility

The study of Rayleigh–Taylor (RT) and Richtmyer–Meshkov (RM) instabilities in a planar geometry at high energy densities at the National Ignition Facility (NIF) requires high spatial resolution imaging. We demonstrate the potential of Fresnel zone plates (FZPs) to achieve resolution that would unlock such studies. FZPs are circular aperiodic gratings that use diffraction to focus x rays and produce an image with high spatial resolution. Taking into account the NIF’s challenging environment, we have designed a specific array of five FZPs for a zinc backlighter to take a radiograph of a target with 9 keV x rays. We measured a mean resolution for the FZP of 1.9µm±0.5µm and a ±1mm depth of focus at an x-ray calibration facility as well as a 2.3µm±0.4µm resolution on a resolution wire mesh shot on the NIF. We also performed an in-depth analysis of the image quality to assess the capability to resolve the small features present in RT and RM instabilities.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2019

Injection laser system for Advanced Radiographic Capability using chirped pulse amplification on the National Ignition Facility

We report on the design, performance, and qualification of the injection laser system designed to deliver joule-level chirped pulse beamlets arranged in dual rectangular beam formats into two main laser amplifier beamlines of the National Ignition Facility. The system is designed to meet the requirements of the Advanced Radiographic Capability upgrade with features that deliver performance, adjustability, and long-term reliability.

47 OTHER INSTRUMENTATION↗
DOE OSTI2016

Method for detection of nuclear-plasma interactions in a 134 Xe-doped exploding pusher at the National Ignition Facility

Angular momentum changes due to nuclear-plasma interactions on highly-excited nuclei in high energy density plasmas created at the National Ignition Facility can be measured through a change in isomer feeding following gamma emission. Here, we propose an experiment to detect these effects in 133 Xe* in exploding pusher capsules.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2012

Characterization of Hydraulic and Ignition Phenomena of Pressurized Water Reactor Fuel Assemblies: Phase II Test Plan

This report summarizes the strategy and preparations for the second phase in the Sandia Fuel Project (SFP) test program. During this phase, five full-length, prototypic 17×17 PWR fuel assembly will simulate a severe loss-of-coolant-accident in the spent fuel pool whereby the fuel is completely uncovered and heats up until ignition of the cladding occurs. Electrically resistive heaters with Zircaloy cladding will substitute for the spent nuclear fuel in the center assembly. This heated assembly will be placed in the center cell of a 3×3 pool rack and will be surrounded by four unheated mock fuel bundles. This arrangement will imitate the situation of a recently offloaded assembly surrounded by much older and thus lower decay heat assemblies. The designs and plans detailed in this report are based on previous testing efforts and represent the current knowledge base. However, these results are subject to change with new information.

Durbin, Samuel G.↗
DOE OSTI2012

Study of Nonlinear Evolution of the Weibel-like Instability of Relativistic Electron Beams Relevant to Fast Ignition and Astrophysics

Relativistic laser matter interaction generates an intense fast electron beam with Mega ampere (MA) to Giga-ampere current. Such beam can propagate into high-density plasmas as background plasma electrons can provide sufficient return current to maintain charge and current neutrality. However, such system is subject to Weibel-like filamentation instabilities that break out the beam into filaments and generate intense magnetic fields. This could result in anomalous stopping and large angular spread of the electron beams, leading to a lower energy coupling to the fuel in the fast ignition (FI) scheme of inertial confinement fusion, therefore, of significant interest to FI. Understanding the nonlinear growth of the Weibel B-fields and its structure is also important to astrophysics as it is generally accepted to be responsible for relativistic collisionless shocks and cosmic rays and “jitter” radiation in gamma ray burst.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

Science of Fusion Ignition on NIF

This report summarizes the discussions and findings of a workshop held in May 2012, to discuss science that has been learned in the National Ignition Campaign, identify new science questions that have arisen, and begin to lay the lines of experimental and theoretical inquiry that could address these over a multi-year time frame.

42 ENGINEERING↗
DOE OSTI2014

National Ignition Facility, High-Energy-Density and Inertial Confinement Fusion, Peer-Review Panel (PRP) Final Report

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is operated as a National Nuclear Security Administration (NNSA) user facility in accordance with Department of Energy (DOE) best practices, including peer-reviewed experiments, regular external reviews of performance, and the use of a management structure that facilitates user and stakeholder feedback. NIF facility time is managed using processes similar to those in other DOE science facilities and is tailored to meet the mix of missions and customers that NIF supports. The NIF Governance Plan describes the process for allocating facility time on NIF and for creating the shot schedule. It also includes the flow of responsibility from entity to entity. The plan works to ensure that NIF meets its mission goals using the principles of scientific peer review, including transparency and cooperation among the sponsor, the NIF staff, and the various user communities. The NIF Governance Plan, dated September 28, 2012, was accepted and signed by LLNL Director Parney Albright, NIF Director Ed Moses, and Don Cook and Thomas D’Agostino of NNSA. Figure 1 shows the organizational structure for NIF Governance.

42 ENGINEERING↗
DOE OSTI2014

Solid Radiochemistry Nuclear Diagnostic Results from Exploding Pusher Shot (N130503-002) at the National Ignition Facility

The Solid Radiochemistry (SRC) nuclear diagnostic platform has been developed for the assessment of various performance parameters, such as areal fuel density and ablator-fuel mixing, associated with the capsule implosion of DT-fuel, hohlraum based shots at the National Ignition Facility (NIF). This diagnostic is based on the collection and characterization of debris from the capsule and surrounding materials (primarily gold from the hohlraum). SRC utilizes two diagnostic instrument manipulators (DIMs), 90-78 and 0-0, to field debris collectors (maximum of four metallic and/or graphite foils per DIM) inside the NIF chamber during shots. The debris collectors are removed after a shot and transferred to the Nuclear Counting Facility (NCF) for the measurement of gold activation (Au-196m and Au-196) and capture (Au-198) products via gamma spectroscopy. The results from SRC which show a strong dependency on an independently measured neutron down scatter ratio (DSR) are utilized as part of a 1-D capsule model to determine the areal densities (ρR(DT) and ρR(CH)) during burn. This report summarizes the SRC results from the Indirect Drive Exploding Pusher shot (N130503-002) designed to produce low ρR at burn time (~40 mg/cm 2 ) leading to a significant decrease in DSR (0.23±0.07 %). As a result, this shot is considered a calibration shot for SRC nuclear diagnostic.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2014

Requirements Document for the Redesign of the DIM-based Diagnostics Transport and Handling System at the National Ignition Facility (NIF)

The National Ignition Facility (NIF, Figure 1) is the world’s leading user research facility for inertial confinement fusion. Diagnostic instruments that collect data from the experiment shots are transported around the facility using a series of disjointed, suboptimal transport and handling (T&H) subsystems that compromise user efficiency and ergonomics. Significant time savings and improvements to the diagnostic exchange process could be realized by designing a new transport and handling system that minimizes the hand-offs between T&H subsystems, reduces operator hassle and ergonomic strain, and improves the long-term maintainability of the system. In contrast to the current system – which employs several manually-operated carts and containers to transport the diagnostic, dock it to its destination, and install it – the new diagnostic transporter integrates the contamination container with the transport cart and provides a dynamic range of adjustability to interface with its destination. This single transporter has the requisite maneuverability, height adjustability, and fine adjustment capabilities without any rigging transactions to support contaminated diagnostic transport and handling at the alignment station and Equatorial and Polar DIMs. A remote-controlled user interface device allows operators a more hands-off experience that reduces ergonomic strain and improves safety. Assuming the cost is not prohibitive, diagnostic storage will be accomplished by simply stowing the transporter in its lowest position in the designated area of NIF. This concept for a new diagnostic transport and handling system would be better aligned with the core values of NIF: safety, quality, and reliability.

42 ENGINEERING↗
DOE OSTI2013

Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

The objective of the proposed project was to confirm the feasibility of using blends of hydrogen and natural gas to improve the performance, efficiency, controllability and emissions of a homogeneous charge compression ignition (HCCI) engine. The project team utilized both engine simulation and laboratory testing to evaluate and optimize how blends of hydrogen and natural gas fuel might improve control of HCCI combustion.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2014

National Ignition Facility Target Diagnostic Waveform Digitization

The purpose of this document is to assess various technologies in electrical waveform digitization for applications at the National Ignition Facility (NIF), more specifically, the Target Diagnostic (TD) department. The findings and recommendations in this memo are meant to inform decisions for future diagnostic implementations and to guide plans for upgrades to existing systems that, due to age or inherent deficiencies, require renewal.

42 ENGINEERING↗
DOE OSTI2015

Deep Dive Topic: Approach to ignition

The current high-foot and related implosions have adequate CR and implosion velocity to ignite, but require improved finesse particularly in, but not limited to, implosion symmetry. This is being pursued. The challenge of controlling drive symmetry is also motivating lower convergence ratio designs. These require higher velocity implosions and are also being pursued.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Concept of operations for channel characterization and simulation of coaxial transmission channels at the National Ignition Facility (NIF)

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) executes experiments for inertial con nement fusion (ICF), world-class high energy density physics (HEDP), and critical national security missions. While the laser systems, target positioners, alignment systems, control systems, etc. enable the execution of such experiments, NIF’s utility would be greatly reduced without its suite of diagnostics. It would be e ectively “blind” to the incredible physics unleashed in its target chamber. Since NIF diagnostics are such an important part of its mission, the quality and reliability of the diagnostics, and of the data recorded from them, is crucial.

42 ENGINEERING↗
DOE OSTI2016

Initiated chemical vapor deposited nanoadhesive for bonding National Ignition Facility's targets

Currently, the target fabrication scientists in National Ignition Facility Directorate at Lawrence Livermore National Laboratory (LLNL) is studying the propagation force resulted from laser impulses impacting a target. To best study this, they would like the adhesive used to glue the target substrates to be as thin as possible. The main objective of this research project is to create adhesive glue bonds for NIF’s targets that are ≤ 1 μm thick. Polyglycidylmethacrylate (PGMA) thin films were coated on various substrates using initiated chemical vapor deposition (iCVD). Film quality studies using white light interferometry reveal that the iCVD PGMA films were smooth. The coated substrates were bonded at 150 °C under vacuum, with low inflow of Nitrogen. Success in bonding most of NIF’s mock targets at thicknesses ≤ 1 μm indicates that our process is feasible in bonding the real targets. Key parameters that are required for successful bonding were concluded from the bonding results. They include inert bonding atmosphere, sufficient contact between the PGMA films, and smooth substrates. Average bond strength of 0.60 MPa was obtained from mechanical shearing tests. The bonding failure mode of the sheared interfaces was observed to be cohesive. Future work on this project will include reattempt to bond silica aerogel to iCVD PGMA coated substrates, stabilize carbon nanotube forests with iCVD PGMA coating, and kinetics study of PGMA thermal crosslinking.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Development on the National Ignition Facility of a High Energy Density Opacity Platform

X-ray opacity is a crucial factor in all radiation-hydrodynamics calculations, yet it is one of the least validated of the material properties in simulation codes for high-energy-density plasmas. Recent opacity experiments at the Sandia Z-machine have shown up to factors of two discrepancies between theory and experiment for various mid-Z elements (Fe, Cr, Ni). These discrepancies raise doubts regarding the accuracy of the opacity models which are used in ICF and stewardship as well as in astrophysics. Therefore, a new experimental opacity platform has been developed on the National Ignition Facility (NIF), not only to verify the Z-machine experimental results, but also to extend the experiments to other temperatures and densities. Within the context of the national opacity strategy, the first NIF experiments were directed towards measuring the opacity of iron at a temperature of ~160 eV and an electron density of ~7xl021 cm-3(Anchor 1). The Z data agree with theory at these conditions, providing a reference point for validation of the NIF platform. Development shots on NIF have demonstrated the ability to create a sufficiently bright point backlighter using an imploding plastic capsule, and also a combined hohlraum, sample and laser drive able to produce iron plasmas at the desired conditions. Spectrometer qualification has been completed, albeit with additional improvements planned, and the first iron absorption spectra have now been obtained.

36 MATERIALS SCIENCE↗
DOE OSTI2017

H_Hyd_Shktub_Mshock_III, JJJ, KKK (S01,S02,S03) on the National Ignition Facility

These experiments are the first experiments in the Mshock campaign at the National Ignition Facility. The experiment is scheduled to be conducted on Dec. 14, 2017. The goal of the Mshock campaign is to study feedthrough dynamics of the Richtmyer- Meshkov instability in a thin layer. These dynamics will be studied in both a reshock configuration (initially) and then in a multi-shock configuration where it is planned to reshock the RM instability up to 3 times (four shocks total).

42 ENGINEERING↗