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Design and analysis of forward and reverse models for predicting defect accumulation, defect energetics, and irradiation conditions

Computational Materials Science

Stewart, James A.; Kohnert, Aaron A.; Capolungo, Laurent; Dingreville, Remi

The complexity of radiation effects in a material's microstructure makes developing predictive models a difficult task. In principle, a complete list of all possible reactions between defect species being considered can be used to elucidate damage evolution mechanisms and its associated impact on microstructure evolution. However, a central limitation is that many models use a limited and incomplete catalog of defect energetics and associated reactions. Even for a given model, estimating its input parameters remains a challenge, especially for complex material systems. Here, we present a computational analysis to identify the extent to which defect accumulation, energetics, and irradiation conditions can be determined via forward and reverse regression models constructed and trained from large data sets produced by cluster dynamics simulations. A global sensitivity analysis, via Sobol’ indices, concisely characterizes parameter sensitivity and demonstrates how this can be connected to variability in defect evolution. Based on this analysis and depending on the definition of what constitutes the input and output spaces, forward and reverse regression models are constructed and allow for the direct calculation of defect accumulation, defect energetics, and irradiation conditions. This computational analysis, exercised on a simplified cluster dynamics model, demonstrates the ability to design predictive surrogate and reduced-order models, and provides guidelines for improving model predictions within the context of forward and reverse engineering of mathematical models for radiation effects in a materials’ microstructure.

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TYPE Conference Poster YEAR 2018
DOIOSTIScopus

DOE/DOT Crude Oil Characterization Research Study, Task 2 Test Report on Evaluating Crude Oil Sampling and Analysis Methods, Revision 1 - Winter Sampling

Lord, David; Allen, Ray; Rudeen, David; Wocken, Chad; Aulich, Ted

The Crude Oil Characterization Research Study is designed to evaluate whether crude oils currently transported in North America, including those produced from “tight” formations, exhibit physical or chemical properties that are distinct from conventional crudes, and how these properties associate with combustion hazards that may be realized during transportation and handling. The current report presents results from Task 2, investigating which commercially available methods can accurately and reproducibly collect and analyze crude oils for vapor pressure and composition, including dissolved gases. This issue, Revision 1 – Winter Sampling, incorporates additional seasonal data and compositional analysis results that have become available since publication of a prior report, SAND2017-12482, released in December 2017. Both reports compare performance of commercially available methods to that of a well-established mobile laboratory system that currently serves as the baseline instrument system for the U.S. Strategic Petroleum Reserve Crude Oil Vapor Pressure Program. The experimental matrix evaluates the performance of selected methods for (i) capturing, transporting, and delivering hydrocarbon fluid samples from the field to the analysis laboratory, coupled with (ii) analyzing for properties related to composition and volatility of the oil, including vapor pressure, gas-oil ratio, and dissolved gases and light hydrocarbons. Several combinations of sample capture and analysis were observed to perform well in both summer and winter sampling environments, though conditions apply that need to be considered carefully for given applications. Methods that perform well from Task 2 will then be utilized in subsequent Task 3 (combustion studies) and Task 4 (compositional analyses of multiple crude types), to be addressed in subsequent reports.

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TYPE SAND Report YEAR 2018
DOIOSTI

Annual Groundwater Monitoring Report Calendar Year 2017

Skelly, Michael; Copland, John R.; Jackson, Timmie O.; Mitchell, Michael M.

Sandia National Laboratories, New Mexico (SNL/NM) is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy's (DOE) National Nuclear Security Administration (NNSA) under contract DE-NA0003525. The DOE/NNSA Sandia Field Office administers the contract and oversees contractor operations at the site.

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TYPE Other Report YEAR 2018
DOIOSTI

Radiological Exposure Devices (RED) Technical Basis for Threat Profile

Bland, Jesse J.; Potter, Charles; Homann, Steven

Facilities that manufacture, store or transport significant quantities of radiological material must protect against the risk posed by sabotage events. Much of the analysis of this type of event has been focused on the threat from a radiological dispersion device (RDD) or "dirty bomb" scenario, in which a malicious assailant would, by explosives or other means, loft a significant quantity of radioactive material into a plume that would expose and contaminate people and property. Although the consequences in cost and psychological terror would be severe, no intentional RDD terrorism events are on record. Conversely, incidents in which a victim or victims were maliciously exposed to a Radiological Exposure Device (RED), without dispersal of radioactive material, are well documented. This paper represents a technical basis for the threat profile related to the risk of nefarious use of an RED, including assailant and material characterization. Radioactive materials of concern are detailed in Appendix A.

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TYPE SAND Report YEAR 2018
DOIOSTI

Installation of Injection Well TAV-INJ1 at the Technical Area-V Groundwater Area of Concern

Lum, Clinton C.L.

This report documents the installation of injection well TAV-INJ1 at the Technical Area-V (TA-V) Groundwater Area of Concern at Sandia National Laboratories, New Mexico (SNL/NM). The U.S. Department of Energy (DOE) and the management and operating contractor for Sandia National Laboratories beginning on May 1, 2017, National Technology & Engineering Solutions of Sandia, LLC (NTESS), hereinafter collectively referred to as DOE/NTESS, prepared this well installation report.

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TYPE Other Report YEAR 2018
DOIOSTI

Enhancing GADRAS Source Term Inputs for Creation of Synthetic Spectra

Horne, Steven M.; Harding, Lee

The Gamma Detector Response and Analysis Software (GADRAS) team has enhanced the source term input for the creation of synthetic spectra. These enhancements include the following: allowing users to programmatically provide source information to GADRAS through memory, rather than through a string limited to 256 characters; allowing users to provide their own source decay database information; and updating the default GADRAS decay database to fix errors and include coincident gamma information.

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TYPE SAND Report YEAR 2018
DOIOSTI

Modeling underwater noise propagation from marine hydrokinetic power devices through a time-domain, velocity-pressure solution

Journal of the Acoustical Society of America

Hafla, E.; Johnson, E.; Johnson, C.N.; Preston, Leiph; Aldridge, D.; Roberts, Jesse D.

Marine hydrokinetic (MHK) devices generate electricity from the motion of tidal and ocean currents, as well as ocean waves, to provide an additional source of renewable energy available to the United States. These devices are a source of anthropogenic noise in the marine ecosystem and must meet regulatory guidelines that mandate a maximum amount of noise that may be generated. In the absence of measured levels from in situ deployments, a model for predicting the propagation of sound from an array of MHK sources in a real environment is essential. A set of coupled, linearized velocity-pressure equations in the time-domain are derived and presented in this paper, which are an alternative solution to the Helmholtz and wave equation methods traditionally employed. Discretizing these equations on a three-dimensional (3D), finite-difference grid ultimately permits a finite number of complex sources and spatially varying sound speeds, bathymetry, and bed composition. The solution to this system of equations has been parallelized in an acoustic-wave propagation package developed at Sandia National Labs, called Paracousti. This work presents the broadband sound pressure levels from a single source in two-dimensional (2D) ideal and Pekeris wave-guides and in a 3D domain with a sloping boundary. The paper concludes with demonstration of Paracousti for an array of MHK sources in a simple wave-guide.

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TYPE Journal Article YEAR 2018
DOIOSTIScopus

sCO2 Brayton Cycle: Roadmap to sCO2 Power Cycles NE Commercial Applications

Mendez, Carmen M.; Rochau, Gary E.

The mission of the Energy Conversion (EC) area of the Advanced Reactor Technology (ART) program is to commercialize the sCO2 Brayton cycle for Advance Reactors and for the Supercritical Transformational Electric Production (STEP) program. The near-term objective of the EC team efforts is to support the development of a commercially scalable Recompression Closed Brayton Cycle (RCBC) to be constructed for the first STEP demonstration system with the lowest risk possible. This document details the status of technology, policy and market considerations, documentation of gaps and needs, and outlines the steps necessary for the successful development and deployment of commercial sCO2 Brayton Power Systems along the path to nuclear reactor applications.

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TYPE SAND Report YEAR 2018
DOIOSTI
Results 31001–31200 of 101,000
Results 31001–31200 of 101,000
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