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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 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Multi-Organization Multi-Discipline Effort Developing a Mitigation Concept for Planetary Defense

There have been significant recent efforts in addressing mitigation approaches to neutralize Potentially Hazardous Asteroids (PHA). One such research effort was performed in 2015 by an integrated, inter-disciplinary team of asteroid scientists, energy deposition modeling scientists, payload engineers, orbital dynamist engineers, spacecraft discipline engineers, and systems architecture engineer from NASAs Goddard Space Flight Center (GSFC) and the Department of Energy (DoE) National Nuclear Security Administration (NNSA) laboratories (Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratories (LLNL) and Sandia National Laboratories). The study team collaborated with GSFCs Integrated Design Centers Mission Design Lab (MDL) which engaged a team of GSFC flight hardware discipline engineers to work with GSFC, LANL, and LLNL NEA-related subject matter experts during a one-week intensive concept formulation study in an integrated concurrent engineering environment. This team has analyzed the first of several distinct study cases for a multi-year NASA research grant. This Case 1 study references the Near-Earth Asteroid (NEA) named Bennu as the notional target due to the availability of a very detailed Design Reference Asteroid (DRA) model for its orbit and physical characteristics (courtesy of the Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) mission team). The research involved the formulation and optimization of spacecraft trajectories to intercept Bennu, overall mission and architecture concepts, and high-fidelity modeling of both kinetic impact (spacecraft collision to change a NEAs momentum and orbit) and nuclear detonation effects on Bennu, for purposes of deflecting Bennu.

Planetary Defense↗
NASA NTRS2017

Studies of Short Time Response Options for Potentially Hazardous Objects: Current and Forthcoming Results

NASA's Goddard Space Flight Center (GSFC) and the National Nuclear Security Administration (NNSA), Department of Energy (DOE) National Laboratories, Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory(LANL), and Sandia National Laboratory (SNL) are collaborating on Planetary Defense Research. The research program is organized around three case studies: 1. Deflection of the Potentially Hazardous Asteroid (PHA) 101955 Bennu (1999 RQ36)[OSIRIS-REx mission target], 2. Deflection of the secondary member of the PHA 65803 Didymos (1996 GT) [DART mission target], 3. Deflection of a scaled-down version of the comet 67PChuryumov-Gerasimenko [Rosetta mission target]. NASAGSFC is providing astrodynamics and spacecraft mission design expertise, while NNSA, DOE, LLNL, LANL and SNL are providing expertise in modeling the effects of kinetic impactor spacecraft and nuclear explosive devices on the target objects.

Mission Design↗
DOE OSTI2014

COMPOSE-HPC: Software Composition for Extreme Scale Computational Science and Engineering

Software composition is an important aspect of computational science software engineering due to large scale production science codes involving multiple programming languages, execution and concurrency models. To date, programmers must manage the complexity of building and maintaining such systems largely by hand with minimal (if any) automated assistance. As such, a great deal of programmer time is spent generating and maintaining code which leads to a high maintenance and development cost, as well as an increased risk of errors being introduced by hand than would be expected in an automated system. COMPOSE-HPC was a multi-institutional effort, with the Galois contribution focused on a specific area of code analysis and software infrastructure. Specifically, Galois led the design and implementation for the Parser for Annotations in a User-specified Language (PAUL), as well as collaborating with SNL and LLNL on the Retargetable Open Transformation Engine (ROTE). Both components were built on top of the ROSE compiler infrastructure from LLNL. All artifacts developed under the COMPOSE-HPC program are available on the github.com and sourceforge.net open source hosting sites under permissive BSD3 software licenses.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2014

Tech Transfer Webinar: Energy Absorbing Materials

A new material has been designed and manufactured at LLNL that can absorb mechanical energy--a cushion--while also providing protection against sheering. This ordered cellular material is 3D printed using direct ink writing techniques under development at LLNL. It is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Livermore Compiler Analysis Loop Suite

LCALS is designed to evaluate compiler optimizations and performance of a variety of loop kernels and loop traversal software constructs. Some of the loop kernels are pulled directly from "Livermore Loops Coded in C", developed at LLNL (see item 11 below for details of earlier code versions). The older suites were used to evaluate floating-point performances of hardware platforms prior to porting larger application codes. The LCALS suite is geared toward assissing C++ compiler optimizations and platform performance related to SIMD vectorization, OpenMP threading, and advanced C++ language features. LCALS contains 20 of 24 loop kernels from the older Livermore Loop suites, plus various others representative of loops found in current production appkication codes at LLNL. The latter loops emphasize more diverse loop constructs and data access patterns than the others, such as multi-dimensional difference stencils. The loops are included in a configurable framework, which allows control of compilation, loop sampling for execution timing, which loops are run and their lengths. It generates timing statistics for analysis and comparing variants of individual loops. Also, it is easy to add loops to the suite as desired.

Hornung, R. D.↗
DOE OSTI2016

Creating a Tiny Human Body on a Chip

LLNL science communicator Maren Hunsberger takes us "Inside the Lab" to learn about the iChip (In-vitro Chip-based Human Investigational Platform) project at Lawrence Livermore National Laboratory. "One application of the iChip system would be to develop new pharmaceutical drugs," explains Dave Soscia, LLNL postdoc. "When you test in a mouse for example, it's not as close to the human system as you can get. If we can take human cells and put them on devices and actually mimic the structure and function of the organ systems in the human, we can actually replace animal testing and even make a better system for testing pharmaceutical drugs."

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Enhanced segmented gamma scanner: White paper

At nuclear facilities, accurate and precise measurements of quantitative activity values and isotopic distributions are needed for radioisotopes in waste items in order to meet the needs of safeguards, criticality controls, facility technical safety requirements, and waste disposal. At the Lawrence Livermore National Laboratory (LLNL), a Canberra WM2200 Segmented Gamma Scanner (SGS) (identified at LLNL as WS1331) was purchased to measure moderate to high levels of special nuclear materials (SNM) in Transuranic (TRU) waste drums generated at the Superblock (SBK) facility. As a result of changes in mission and in waste processing and packaging procedures, the majority of the waste items generated at SBK now only contain moderate to low levels of SNM. Modifications were needed to WS1331 to meet the measurement needs for the lower activity items. An additional Canberra LYNX Digital Signal Processor (DSP) was added to the nuclear instrumentation of WS1331 so optimized spectra could be acquired for both the quantitative activity and isotopic results. After the system was enhanced, measurements were collected to evaluate and assess the impact of the change on results. As a result, the measurement tests indicate that the additional DSP improved the performance of WS1331 for lower activity TRU waste drums.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Multiple Independent File Parallel I/O with HDF5

The HDF5 library has supported the I/O requirements of HPC codes at Lawrence Livermore National Labs (LLNL) since the late 90’s. In particular, HDF5 used in the Multiple Independent File (MIF) parallel I/O paradigm has supported LLNL code’s scalable I/O requirements and has recently been gainfully used at scales as large as O(10 6 ) parallel tasks.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2017

Axial deformed solution of the Skyrme-Hartree-Fock-Bogolyubov equations using the transformed harmonic oscillator Basis

HFBTHO is a physics computer code that is used to model the structure of the nucleus. It is an implementation of the nuclear energy Density Functional Theory (DFT), where the energy of the nucleus is obtained by integration over space of some phenomenological energy density, which is itself a functional of the neutron and proton densities. In HFBTHO, the energy density derives either from the zero-range Dkyrme or the finite-range Gogny effective two-body interaction between nucleons. Nuclear superfluidity is treated at the Hartree-Fock-Bogoliubov (HFB) approximation, and axial-symmetry of the nuclear shape is assumed. This version is the 3rd release of the program; the two previous versions were published in Computer Physics Communications [1,2]. The previous version was released at LLNL under GPL 3 Open Source License and was given release code LLNL-CODE-573953.

Perez, R. Navarro↗
DOE OSTI2018

What is Machine Learning?

Have you ever been unsure what people mean when they talk about 'machine learning'? What machines? And what are they learning? This video is for you! For more information about Machine Learning at LLNL and other Data Science projects, visit the LLNL Data Science Institute website at data-science.llnl.gov

3-D PRINTING↗
DOE OSTI2018

An Overview of Nondestructive Evaluation and Characterization at Lawrence Livermore National Laboratory

For more than 60 years, Lawrence Livermore National Laboratory (LLNL) has developed and employed advanced technologies in both nondestructive evaluation (NDE) and nondestructive characterization (NDC) to enhance national security. Additonally, the Laboratory established an extensive array of NDC capabilities that enable the inspection and characterization of virtually every element on the periodic table. This allows for the evaluation of structures of interest with densities ranging from ~20 mg/cm 3 to approximately 20 g/cm 3 , across length scales from nanometers to meters, and over time scales ranging from microseconds to decades. This paper provides an overview of the NDE and NDC activities at LLNL, illuminating current research and development interests in well-established areas such as weapons and explosives research, and in new areas such as additive manufacturing. Traditional NDC techniques, such as X-ray radiography and computed tomography, are also discussed. Furthermore, new approaches, such as X-ray phase-contrast imaging and X-ray ptychography, are examined.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Godiva-IV Dosimetry Exercise 2022 Preliminary Results

Integral Experiment Request (IER) 538 is part of a series of dose characterization and nuclear accident dosimetry (NAD) exercises performed under the Department of Energy (DOE) Nuclear Criticality Safety Program (NCSP). This is the second NAD exercise using the Godiva-IV critical assembly and the third NAD exercise overall. The participating laboratories provided their own dosimeters that were mounted on the Lawrence Livermore National Laboratory (LLNL) BOttle Manikin ABsorption (BOMAB) phantoms and aluminum plates. The BOMABs and plates were placed at two, three, and four meters away from the center of Godiva. Alongside the NADs, there was a LLNL Passive Neutron Spectrometer (PNS), Atomic Weapons Establishment (AWE) PNS, and Y-12 Sphere present to measure the neutron dose from Godiva. Two irradiations were conducted to test the NAD performance from each laboratory and assesses their performance to the DOE-STD-1098-2017 part 515 criteria. Neutron and gamma doses were measured prior to this exercise. This work presents a model for the neutron and gamma dose respectively to serve as the reference value. A code written in C/C++/ROOT was used to fit the measured neutron and gamma dose with the new models. It was assumed that the neutron and gamma doses are proportional to the change in temperature of Godiva after a burst irradiation. Uncertainties for the reference values were calculated using error propagation of the model’s parameters. Preliminary results (within twenty-four hours) and final results were compared for each laboratory. On average of all the participating laboratories, 32% of neutron doses and 78% of gamma doses were outside the DOE standards. One laboratory did not report their dose readings and were not included in this average. There is a bias for a lower neutron dose and a higher gamma dose based on the distribution of results. In comparison with the past Godiva-IV NAD exercise, there is an improvement in neutron dose readings by 20%.

BOttle Manikin ABsorption (BOMAB)↗
DOE OSTI2013

Cyclus fuel cycle simulation capabilities with the CYDER disposal system model

An algorithm and supporting database for rapid thermal repository loading calculation was implemented in CYDER. This algorithm employs a Specific Temperature Change (STC) method and has resulted from combining detailed spent nuclear fuel composition data with a detailed thermal repository performance analysis tool from Lawrence Livermore National Laboratory (LLNL), Argonne National Laboratory (ANL), and the Used Fuel Disposition (UFD) campaign. By abstraction of and benchmarking against these detailed thermal models, CYDER captures the dominant physics of thermal phenomena affecting repository capacity in various geologic media and as a function of spent fuel composition. Abstraction based on detailed computational thermal repository performance calculations with the LLNL semi-analytic model has resulted in implementation of the STC estimation algorithm and a supporting reference dataset. This method is capable of rapid estimation of temperature increase near emplacement tunnels as a function of waste composition, limiting radius, waste package spacing, near field thermal conductivity and near field thermal diffusivity. The sensitivity analyses and validation efforts conducted in this work demonstrate the capability of the CYDER tool to provide repository capacity and performance metrics in the context of dynamic fuel cycle.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2018

Legacy Facility Risk Reduction - Challenges, Strategies, Partnerships, and Benefits Lawrence Livermore National Laboratory - 18463

As Lawrence Livermore National Laboratory (LLNL) carries out its national security missions, we strive to ensure our facility portfolio meets the latest technologies and addresses challenges presented by its aging infrastructure. Established in 1942 as a Naval Air Station, repurposed in 1952 by the Atomic Energy Commission (AEC), LLNL continues to host a robust National Nuclear Security Administration (NNSA) Research and Development (R and D) mission. As an aging site, many of its facilities have met their life cycle contribution. As process contaminated facilities are decommissioned, new challenges arise in their near-term stewardship and long-term disposition actions, presenting risk reduction opportunities. The challenge has been to determine approaches to steward such risks, stabilize, advocate for long-term mitigation, and take actions to eliminate risks. Encumbered within is the balance of priorities in supporting ongoing and emerging mission and those of past legacy activities. This paper will endeavor to highlight Challenges and Benefits presented by such a paradigm, where we identified Strategies and Partnerships working towards mutual Risk Reduction activities. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2016

Characterization of Plutonium-Contaminated Gloveboxes using a High-Range Alpha Ion Chamber

Between September 2014 and July 2015, personnel at Lawrence Livermore National Laboratory (LLNL) decontaminated, characterized, and removed six high-activity plutonium-contaminated gloveboxes from the Building 332 Plutonium Facility. This project was based on similar decommissioning work that was done at the Rocky Flats Environmental Technology Site (RFETS), using a Ludlum Model 43-132 ion chamber with Model 195 readout unit. This summary describes the process that was used at LLNL to characterize all six gloveboxes as low-level waste. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Using the MCNP6.2 Correlated Fission Multiplicity Models, CGMF and FREYA

The culmination of a multi-year, collaborative effort by researchers at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Lawrence Livermore National Laboratory (LLNL) and the University of Michigan, led to the delivery of two new correlated fission multiplicity models available within the latest release of MCNP{sup R} version 6.2. The needs within the nuclear nonproliferation community, particularly in simulating and predicting the neutron and gamma-ray signatures of special nuclear materials (SNM), provided the motivation for this major collaborative effort. From LANL, the CGMF code has been implemented as an upgrade to the original Cascading Gamma-ray Multiplicity (CGM) code. Additionally, the LLNL Fission Library has been upgraded from the original implementation released in prior versions of MCNP6/X to include the LBNL/LLNL Fission Reaction Event Yield Algorithm (FREYA) code. Both new codes are capable of simulating fission events with correlated neutron and gamma-ray emissions. Due to the release of these new models within MCNP6.2, the purpose of this paper is to describe the differences between these new models and existing capabilities, demonstrate their use in the context of simulation inputs and outputs, and to discuss some of the ongoing work directed toward the next generation of these features.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Awe Bonner sphere measurements of the neutron leakage spectrum from the GODIVIA-IV critical assembly at NCERC - 14413

The US National Criticality Experiments Research Centre (NCERC) is home to several critical assembly machines that were relocated from Los Alamos National Laboratory in the last decade. The centre is sponsored by the Department of Energy's Nuclear Criticality Safety Program (NCSP), which has the mission to ensure the safe handling of fissile materials from a criticality perspective. Under the auspices of the NCSP, Lawrence Livermore National Laboratory (LLNL) is planning to host an international inter-comparison of nuclear accident dosimetry (NAD) using the Godiva-IV assembly at NCERC. The inter-comparison is motivated by a decline in the frequency of performance testing of NADs (both in the US, the UK and France) and the desire to modernize and harmonize dosimetry systems. A pre-requisite for the inter-comparison is the characterisation of the neutron and gamma-ray leakage spectra associated with the Godiva-IV assembly at NCERC. AWE provided its Bonner-sphere spectrometry capability to LLNL for two experimental campaigns, in November 2013 and May 2014, to measure the neutron leakage spectrum of the assembly in both a sub-critical 'steady-state' and a super-prompt-critical 'burst'. Nine points, at distances from 2 to 4 meters from the machine were measured with the Bonner-sphere spectrometer using both an active He-3 detector and a passive technique employing gold foils. This paper presents the spectra unfolded from the data and integral dose values, and compares these to previously published data. The limitations of the work and future plans are also discussed. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2022

Impacts of processing decisions on TNSL cross sections and their applications

Thermal neutron scattering law (TNSL) data describe low-energy neutrons scattering off of bound materials, and can have a significant impact on modeling any system with slow neutrons, including nuclear reactors. Previous work to introduce TNSL data to neutron transport codes at LLNL focused on COG and TART, with the limitation that these codes require highly specialized data processing and formatting. We have recently increased efforts to process TNSL data with the LLNL nuclear data processing code FUDGE. FUDGE reads and writes the evaluated and processed files using the generalized nuclear database structure (GNDS). This process uncovered some significant difficulties in processing TNSL data, and unearthed assumptions made in current TNSL data processing that we have found inadequate. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗