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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 1,225 records · Page 68
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

ASC Co-design Proxy App Strategy

The NNSA labs representing the ASC program are coordinating on the development and release of a portfolio of proxy applications to be used in co-design. While each lab will develop their own set of proxy apps that represent the applications and algorithms of interest to them, we propose a common set of criteria to describe and measure proxy apps, and a strategy aimed at minimizing duplication and maximizing impact across the entire ASC proxy app portfolio. Proxy application (or proxy apps for short) is a catchall term for the simplification of characteristics of real applications that are of interest to DOE. These proxy apps are used in the co-design process as concrete examples for component and system designers to understand our software requirements. The proxy apps are generally openly available to the co-design community and, unlike benchmarks, are intended to facilitate the two-way communication required by co-design to optimally evaluate trade-offs in the system hardware, and inform the developer community of programming best practices for emerging architectures.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2017

Data Structures for Extreme Scale Computing

As computing problems of national importance grow, the government meets the increased demand by funding the development of ever larger systems. The overarching goal of the work supported in part by this grant is to increase efficiency of programming and performing computations on these large computing systems. In past work, we have demonstrated that some of these computations once thought to require expensive hardware designs and/or complex, special-purpose programming may be executed efficiently on low-cost commodity cluster computing systems using a general-purpose “latency-tolerant” programming framework. One important developed application of the ideas underlying this framework is graph database technology supporting social network pattern matching used by US intelligence agencies to more quickly identify potential terrorist threats. This database application has been spun out by the Pacific Northwest National Laboratory, a Department of Energy Laboratory, into a commercial start-up, Trovares Inc. We explore an alternative application of the same underlying ideas to a well-studied challenge arising in engineering: solving unstructured sparse linear equations. Solving these equations is key to predicting the behavior of large electronic circuits before they are fabricated. Predicting that behavior ahead of fabrication means that designs can optimized and errors corrected ahead of the expense of manufacture.

42 ENGINEERING↗
DOE OSTI2019

Underground Test Area Activity Preemptive Review Guidance Nevada National Security Site, Nevada

This report is a revision to the preemptive review (PER) guidance originally released as U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Field Office (NNSA/NFO) document DOE/NV--1552 in 2016 (NNSA/NFO, 2016). PER committees review various products, including data, documents, software/codes, analyses, and models. PER committees provide technical recommendations to support regulatory decisions that are the responsibility of the DOE Environmental Management (EM) Nevada Program and NDEP. PERs are designed to be adaptable to the varying requirements of individual CAU studies. Their goals include the following: Maintaining high technical standards; ensuring work is technically adequate, competently performed, and documented consistent with other programmatic documents; and verifying that established quality requirements are satisfied. Helping focus CAU studies on UGTA Activity objectives identified in the FFACO by implementing Section 3 of Appendix VI, which includes the UGTA Strategy Flowchart (Figure 3-2) and Process Flow Diagram Dictionary for the UGTA CAUs (Table 3-1). Providing a mechanism for early identification of technical and/or strategy issues that could affect successfully implementing the UGTA strategy. Providing assurance to NDEP that work in progress and final reports are technically sound. Providing independent reviews that allow for a better understanding of the technical work, and result in products that are transparent and sufficient to allow the DOE EM Nevada Program to meet regulatory objectives.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Margin to Onset of Nucleate Boiling studies for MITR and NBSR Design Demonstration Experiments

The United State High Performance Research Reactor (USHPRR) program aims to eliminate more than 200kg of High Enriched Uranium (HEU) from commerce annually by converting five U.S. high-performance research reactors and one associated critical assembly to Low Enriched Uranium (LEU) fuel using a high-density alloy of uranium-10 wt% molybdenum (U-10Mo). The Massachusetts Institute of Technology Reactor (MITR) and the National Bureau of Standards Reactor (NBSR) are two of five research reactors selected for this program. Previous studies have addressed the thermal-hydraulics performance of the fuel Design Demonstration Elements (DDE) for these reactors under conservative assumptions in the Belgian Reactor (BR)-2. This report extends these previous studies by analyzing the margins to Onset of Nucleate Boiling (ONB) for these two DDEs under the conservative conditions used in the previous thermal-hydraulics analyses

42 ENGINEERING↗
DOE OSTI2011

Continuous Efforts to Develop the National System for Material Control and Accounting Training at the George Kuzmycz Training Center

The George Kuzmycz Training Center (GKTC) for Physical Protection, Control and Accounting of Nuclear Materials was established in 1998 at the Kyiv Institute of Nuclear Research of the Ukrainian Academy of Sciences through the collaborative efforts of the United States and Ukraine. Later the European Commission (EC) joined the US in assisting with the Material Control and Accounting (MC&A) part of the GKTC training program. The Government of Ukraine designated the GKTC as the National Center responsible for providing training and methodological support for nuclear facilities and nuclear specialists in the Material Protection, Control and Accounting (MPC&A) area. To increase the efficiency of the State MC&A system an essential number of new regulations, norms and rules have been developed; some of them mandate regular and more intensive training of MC&A specialists in the industry - from those working at the Nuclear Regulatory Authority of Ukraine to the personnel of nuclear facilities. To meet such regulations GKTC plans to develop next year a number of training courses under the EC contract; such courses will reflect both the specifics of Ukrainian nuclear facilities and the level of expertise of the facilities’ personnel. The NDA training laboratory, established in 2003 with US DOE financial support and technical and methodological assistance, considerably expanded the GKTC’s training capabilities for MC&A programs. Next year that lab will be supplemented with a new NM Surveillance and Containment laboratory as current plans call for under the EC contract. The US DOE is also providing funding to support that project. Under the EC contract the laboratory will be equipped with state-of-the-art, advanced surveillance and containment equipment which will strengthen and expand even further the GKTC’s training capabilities and potential. This will allow GKTC to train Ukrainian nuclear industry specialists in practically all MC&A topics. Furthermore, GKTC is planning to offer already this year and to continue offering in the future, on a regular basis, the courses that have already been developed, while continuing to develop new ones. This paper briefly describes the work done to upgrade the Ukrainian MC&A system, both at the State and at the facilities’ levels, as well as the results of efforts to develop the National System for training MC&A personnel at the GKTC. It also describes problems encountered and their solution; it includes comments, suggestions and recommendations for future activities to promote and improve the nuclear material management culture in Ukraine.

Gavrilyuk, Victor I.↗
DOE OSTI2020

Pilgrim : A thermal rate constant calculator and a chemical kinetics simulator

Pilgrim is a program written in Python and designed to use direct dynamics in the calculation of thermal rate constants of chemical reactions by the variational transition state theory (VTST), based on electronic structure calculations for the potential energy surface. Pilgrim can also simulate reaction mechanisms using kinetic Monte Carlo (KMC). For reaction processes with many elementary steps, the rate constant of each of these steps can be calculated by means of conventional transition state theory (TST) or by using VTST. In the current version, Pilgrim can evaluate thermal rates using the canonical version of reaction-path VTST, which requires the calculation of the minimum energy path (MEP) associated with each elementary step or transition structure. Multi-dimensional quantum effects can be incorporated through the small-curvature tunneling (SCT) approximation. These methodologies are available both for reactions involving a single structure of the reactants and the transition state and also for reactions involving flexible molecules with multiple conformations of the reactant and/or of the transition state. For systems with many conformers, the program can evaluate each of the elementary reaction rate constants by multipath canonical VTST or multi-structural VTST. Moreover, the reactant can be unimolecular or bimolecular. Torsional anharmonicity can be incorporated through either the MSTor or the Q2DTor programs. Dual-level calculations are also available in Pilgrim: automatic high-level single-point energies can be used to correct the energy of reactants, transition states, products, and MEP points using the interpolated single-point energies (ISPE) algorithm. When the rate constants of all the chemical processes of interest are known, by means of their calculation using Pilgrim or alternatively through analytical fits to the rate constants as functions of temperature, it is possible to simulate a multistep mechanism under specified laboratory conditions using KMC. Finally, this algorithm allows performing a kinetic simulation to monitor the evolution of each chemical species with time and obtain the product yields.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2013

NSDann2BS, a neutron spectrum unfolding code based on neural networks technology and two bonner spheres

In this work a neutron spectrum unfolding code, based on artificial intelligence technology is presented. The code called ''Neutron Spectrometry and Dosimetry with Artificial Neural Networks and two Bonner spheres'', (NSDann2BS), was designed in a graphical user interface under the LabVIEW programming environment. The main features of this code are to use an embedded artificial neural network architecture optimized with the ''Robust design of artificial neural networks methodology'' and to use two Bonner spheres as the only piece of information. In order to build the code here presented, once the net topology was optimized and properly trained, knowledge stored at synaptic weights was extracted and using a graphical framework build on the LabVIEW programming environment, the NSDann2BS code was designed. This code is friendly, intuitive and easy to use for the end user. The code is freely available upon request to authors. To demonstrate the use of the neural net embedded in the NSDann2BS code, the rate counts of {sup 252}Cf, {sup 241}AmBe and {sup 239}PuBe neutron sources measured with a Bonner spheres system.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

High-quality Extragalactic Legacy-field Monitoring (HELM) with DECam

High-quality Extragalactic Legacy-field Monitoring (HELM) is a long-term observing program that photometrically monitors several well-studied extragalactic legacy fields with the Dark Energy Camera (DECam) imager on the CTIO 4m Blanco telescope. Since Feb 2019, HELM has been monitoring regions within COSMOS, XMM-LSS, CDF-S, S-CVZ, ELAIS-S1, and SDSS Stripe 82 with few-day cadences in the $(u)gri(z)$ bands, over a collective sky area of $\sim 38$ deg${\rm ^2}$. The main science goal of HELM is to provide high-quality optical light curves for a large sample of active galactic nuclei (AGNs), and to build decades-long time baselines when combining past and future optical light curves in these legacy fields. These optical images and light curves will facilitate the measurements of AGN reverberation mapping lags, as well as studies of AGN variability and its dependences on accretion properties. In addition, the time-resolved and coadded DECam photometry will enable a broad range of science applications from galaxy evolution to time-domain science. We describe the design and implementation of the program and present the first data release that includes source catalogs and the first $\sim 3.5$ years of light curves during 2019A--2022A.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

Multi‐dimensional lock‐free arrays for multithreaded mode‐directed tabling in Prolog

Summary This work proposes a new design for the supporting data structures used to implement multithreaded tabling in Prolog systems. Tabling is an implementation technique that improves the expressiveness of traditional Prolog systems in dealing with recursion and redundant computations. Mode‐directed tabling is an extension to the tabling technique that supports the definition of alternative criteria for specifying how answers are aggregated, thus being very suitable for problems where the goal is to dynamically calculate optimal or selective answers. In this work, we leverage the intrinsic potential that mode‐directed tabling has to express dynamic programming problems by creating a new design that improves the representation of multi‐dimensional arrays in the context of multithreaded tabling. To do so, we introduce a new mode for indexing arguments in mode‐directed tabled evaluations, named dim , where each dim argument features a uni‐dimensional lock‐free array. Experimental results using well‐known dynamic programming problems on a 32‐core machine show that the new design introduces less overheads and clearly improves the execution time for sequential and multithreaded tabled evaluations.

Areias, Miguel↗
DOE OSTI2016

WE-H-BRA-04: Biological Geometries for the Monte Carlo Simulation Toolkit TOPASNBio

Purpose: New advances in radiation therapy are most likely to come from the complex interface of physics, chemistry and biology. Computational simulations offer a powerful tool for quantitatively investigating radiation interactions with biological tissue and can thus help bridge the gap between physics and biology. The aim of TOPAS-nBio is to provide a comprehensive tool to generate advanced radiobiology simulations. Methods: TOPAS wraps and extends the Geant4 Monte Carlo (MC) simulation toolkit. TOPAS-nBio is an extension to TOPAS which utilizes the physics processes in Geant4-DNA to model biological damage from very low energy secondary electrons. Specialized cell, organelle and molecular geometries were designed for the toolkit. Results: TOPAS-nBio gives the user the capability of simulating biological geometries, ranging from the micron-scale (e.g. cells and organelles) to complex nano-scale geometries (e.g. DNA and proteins). The user interacts with TOPAS-nBio through easy-to-use input parameter files. For example, in a simple cell simulation the user can specify the cell type and size as well as the type, number and size of included organelles. For more detailed nuclear simulations, the user can specify chromosome territories containing chromatin fiber loops, the later comprised of nucleosomes on a double helix. The chromatin fibers can be arranged in simple rigid geometries or within factual globules, mimicking realistic chromosome territories. TOPAS-nBio also provides users with the capability of reading protein data bank 3D structural files to simulate radiation damage to proteins or nucleic acids e.g. histones or RNA. TOPAS-nBio has been validated by comparing results to other track structure simulation software and published experimental measurements. Conclusion: TOPAS-nBio provides users with a comprehensive MC simulation tool for radiobiological simulations, giving users without advanced programming skills the ability to design and run complex simulations.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

ES4SE Technical Assistance Program Evaluation

Technical assistance (TA) programs can provide organizations and communities with the information, tools, and resources needed to support their development and resilience goals. The Energy Storage for Social Equity (ES4SE) TA program sought to empower undeserved communities through co-development of energy storage pathways and solutions to address community-defined challenges and needs. Evaluating the design, implementation, and outcomes of TA programs like ES4SE is critical to understanding whether program and participant goals were accomplished and how to adjust the TA approach to better meet participant needs. This evaluation explores the experiences and perceptions of community participants in the ES4SE TA program.

25 ENERGY STORAGE↗
DOE OSTI2021

Integrated Energy Systems Program Management Plan

In 2012, the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE) initiated the Nuclear Energy Enabling Technology Program, which includes the Crosscutting Technology Development (CTD) portfolio of subprograms, to conduct research, development, and demonstration (RD&D) to support existing, new and advanced reactor designs and fuel cycle technologies. This program plan describes the Integrated Energy Systems (IES) Program, an element of the CTD portfolio since 2016 that seeks to improve the economic competitiveness, efficiency and environmental performance of nuclear energy systems by expanding their potential application space beyond electricity and optimizing their utilization in the context of the larger U.S. electric and non-electric energy system.

08 HYDROGEN↗
DOE OSTI2011

A Laser Interferometric Miniature Sensor

This is the second year of a Phase II Small Business Innovation Research (SBIR) contract geared towards the development of a new seismic sensor. Ground-based seismic monitoring systems have proven to be very capable in identifying nuclear tests, and can provide somewhat precise information on the location and yield of the explosive device. Making these measurements, however, currently requires very expensive and bulky seismometers that are difficult to deploy in places where they are most needed. A high performance, compact device can enable rapid deployment of large scale arrays, which can in turn be used to provide higher quality data during times of critical need. The use of a laser interferometer-based device has shown considerable promise, while also presenting significant challenges. The greatest strength of this optical readout technique is the ability to decouple the mechanical design from the transducer, thus enabling a miniaturized design that is not accessible with conventional sensing techniques. However, the nonlinearity in the optical response must be accounted for in the sensor output. Previously, we had proposed using a force-feedback approach to position the sensor at a point of maximum linearity. However, it can be shown that the combined nonlinearities of the optical response and the force-feedback curve necessarily results in a significant amount of unwanted noise at low frequencies. Having realized this, we have developed a new approach that eliminates force feedback, allowing the proof mass to move freely at all times. This takes advantage of some advanced optical spatial filtering that was developed at Symphony Acoustics for other types of sensors, and was recently adapted to this work. After processing the signals in real time, the digital output of the device is intrinsically linear, and the sensor can operate at any orientation with the same level of resolution, while instantly adapting to significant changes in orientation. Ultimately, we expect the dynamic range to be up to 180 dB. Currently, we have observed the noise floor in a 0.1 Hz to 10 Hz bandwidth to be near -160 dB/Hz relative to 1 m2/s4. To meet the objectives of this program, we are finalizing the design of a 3 axis sensor for shallow borehole deployments, with a diameter of 40 mm and a length a 150 mm.

47 OTHER INSTRUMENTATION↗
DOE OSTI2016

Evolvix BEST Names for semantic reproducibility across code2brain interfaces

Names in programming are vital for understanding the meaning of code and big data. We define code2brain (C2B) interfaces as maps in compilers and brains between meaning and naming syntax, which help to understand executable code. While working toward an Evolvix syntax for general‐purpose programming that makes accurate modeling easy for biologists, we observed how names affect C2B quality. To protect learning and coding investments, C2B interfaces require long‐term backward compatibility and semantic reproducibility (accurate reproduction of computational meaning from coder‐brains to reader‐brains by code alone). Semantic reproducibility is often assumed until confusing synonyms degrade modeling in biology to deciphering exercises. We highlight empirical naming priorities from diverse individuals and roles of names in different modes of computing to show how naming easily becomes impossibly difficult. We present the Evolvix BEST (Brief, Explicit, Summarizing, Technical) Names concept for reducing naming priority conflicts, test it on a real challenge by naming subfolders for the Project Organization Stabilizing Tool system, and provide naming questionnaires designed to facilitate C2B debugging by improving names used as keywords in a stabilizing programming language. Our experiences inspired us to develop Evolvix using a flipped programming language design approach with some unexpected features and BEST Names at its core.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2012

Light Water Reactor Sustainability Program: Risk-Informed Safety Margins Characterization (RISMC) Pathway Technical Program Plan

Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). As the current Light Water Reactor (LWR) NPPs age beyond 60 years, there are possibilities for increased frequency of Systems, Structures, and Components (SSCs) degradations or failures that initiate safety-significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly “over-design” portions of NPPs and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degree of assurance. This form of defense-in-depth is a reasoned response to uncertainties and is often referred to generically as “safety margin.” Historically, specific safety margin provisions have been formulated, primarily based on “engineering judgment.”

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2016

Light Water Reactor Sustainability Program: Risk-Informed Safety Margins Characterization (RISMC) Pathway Technical Program Plan

Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). As the current Light Water Reactor (LWR) NPPs age beyond 60 years, there are possibilities for increased frequency of Systems, Structures, and Components (SSCs) degradations or failures that initiate safety-significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly “over-design” portions of NPPs and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degree of assurance. This form of defense-in-depth is a reasoned response to uncertainties and is often referred to generically as “safety margin.” Historically, specific safety margin provisions have been formulated, primarily based on “engineering judgment.”

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2020

The Astrophysics Program of NOvA [Poster]

The NOvA detectors, designed primarily to discover and measure electron neutrino appearance in a muon neutrino beam, are versatile instruments being used for a variety of astrophysical analyses.

79 ASTRONOMY AND ASTROPHYSICS↗