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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 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

A Preliminary Review of U.S. Forest Service Business Practices To Authorize Special Uses, Including Energy Infrastructure Projects, on National Forest System Lands

The U.S. Forest Service (USFS) Special Uses-Lands Program is in jeopardy. Although this program, authorized in Title 36, Part 251, of the U.S. Code of Federal Regulations (36 CFR Part 251), ranks among the top four revenue-generating programs for use of National Forest System (NFS) lands, along with the Timber, Minerals, and Special Uses-Recreation Programs, the Special Uses-Lands Program is in a state of neglect. Repeated cuts in funding (a decrease of 26% from fiscal years 2010 to 2014) are adversely affecting staffing and training, which in turn is affecting timely permit processing and ultimately the public’s ability to use and benefit from NFS lands. In addition, highly experienced staff with valuable institutional knowledge of the program have begun to retire. The ability of the program to function under these dire circumstances can be attributed to the dedication of Special Uses staff to the program and their commitment to the public. The initial focus of this report was to identify opportunities for improving performance of permitting and review for large energy infrastructure-related projects. However, it became clear during this analysis that these projects are generally adequately staffed and managed. This is due in large part to the availability of cost-recovery dollars and the high-profile nature of these projects. However, it also became apparent that larger issues affecting the bulk of the work of the Special Uses-Lands Program need to be addressed immediately. This report is a preliminary examination of the state of the Special Uses-Lands Program and focuses on a few key items requiring immediate attention. Further investigation through case studies is recommended to dig deeper into the Special Uses-Lands Program business process to determine the most costeffective strategies for streamlining the overall process and the metrics by which performance can be evaluated, including for the permitting and tracking of energy infrastructure projects.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2013

Convergence studies of deterministic methods for LWR explicit reflector methodology

The standard approach in modem 3-D core simulators, employed either for steady-state or transient simulations, is to use Albedo coefficients or explicit reflectors at the core axial and radial boundaries. In the latter approach, few-group homogenized nuclear data are a priori produced with lattice transport codes using 2-D reflector models. Recently, the explicit reflector methodology of the deterministic CASMO-4/SIMULATE-3 code system was identified to potentially constitute one of the main sources of errors for core analyses of the Swiss operating LWRs, which are all belonging to GII design. Considering that some of the new GIII designs will rely on very different reflector concepts, a review and assessment of the reflector methodology for various LWR designs appeared as relevant. Therefore, the purpose of this paper is to first recall the concepts of the explicit reflector modelling approach as employed by CASMO/SIMULATE. Then, for selected reflector configurations representative of both GII and GUI designs, a benchmarking of the few-group nuclear data produced with the deterministic lattice code CASMO-4 and its successor CASMO-5, is conducted. On this basis, a convergence study with regards to geometrical requirements when using deterministic methods with 2-D homogenous models is conducted and the effect on the downstream 3-D core analysis accuracy is evaluated for a typical GII deflector design in order to assess the results against available plant measurements. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2020

Scalable molecular dynamics on CPU and GPU architectures with NAMD

NAMD is a molecular dynamics program designed for high-performance simulations of very large biological objects on CPU- and GPU-based architectures. NAMD offers scalable performance on petascale parallel supercomputers consisting of hundreds of thousands of cores, as well as on inexpensive commodity clusters commonly found in academic environments. It is written in C++ and leans on Charm++ parallel objects for optimal performance on low-latency architectures. NAMD is a versatile, multipurpose code that gathers state-of-the-art algorithms to carry out simulations in apt thermodynamic ensembles, using the widely popular CHARMM, AMBER, OPLS, and GROMOS biomolecular force fields. Here, we review the main features of NAMD that allow both equilibrium and enhanced-sampling molecular dynamics simulations with numerical efficiency. We describe the underlying concepts utilized by NAMD and their implementation, most notably for handling long-range electrostatics; controlling the temperature, pressure, and pH; applying external potentials on tailored grids; leveraging massively parallel resources in multiple-copy simulations; and hybrid quantum-mechanical/molecular-mechanical descriptions. We detail the variety of options offered by NAMD for enhanced-sampling simulations aimed at determining free-energy differences of either alchemical or geometrical transformations and outline their applicability to specific problems. Last, we discuss the roadmap for the development of NAMD and our current efforts toward achieving optimal performance on GPU-based architectures, for pushing back the limitations that have prevented biologically realistic billion-atom objects to be fruitfully simulated, and for making large-scale simulations less expensive and easier to set up, run, and analyze. NAMD is distributed free of charge with its source code at www.ks.uiuc.edu.

high-performance computing↗
NASA NTRS1993

[Genotoxic modification of nucleic acid bases and biological consequences of it. Review and prospects of experimental and computational investigations]

The review is presented of experimental and computational data on the influence of genotoxic modification of bases (deamination, alkylation, oxidation) on the structure and biological functioning of nucleic acids. Pathways are discussed for the influence of modification on coding properties of bases, on possible errors of nucleic acid biosynthesis, and on configurations of nucleotide mispairs. The atomic structure of nucleic acid fragments with modified bases and the role of base damages in mutagenesis and carcinogenesis are considered.

Non-NASA Center↗
DOE OSTI2015

TU-G-204-06: Correlation Between Texture Analysis-Based Model Observer and Human Observer in Diagnosis of Ischemic Infarct in Non-Contrast Head CT of Adults

Purpose: To investigate the correlation between texture analysis-based model observer and human observer in the task of diagnosis of ischemic infarct in non-contrast head CT of adults. Methods: Non-contrast head CTs of five patients (2 M, 3 F; 58–83 y) with ischemic infarcts were retro-reconstructed using FBP and Adaptive Statistical Iterative Reconstruction (ASIR) of various levels (10–100%). Six neuro -radiologists reviewed each image and scored image quality for diagnosing acute infarcts by a 9-point Likert scale in a blinded test. These scores were averaged across the observers to produce the average human observer responses. The chief neuro-radiologist placed multiple ROIs over the infarcts. These ROIs were entered into a texture analysis software package. Forty-two features per image, including 11 GLRL, 5 GLCM, 4 GLGM, 9 Laws, and 13 2-D features, were computed and averaged over the images per dataset. The Fisher-coefficient (ratio of between-class variance to in-class variance) was calculated for each feature to identify the most discriminating features from each matrix that separate the different confidence scores most efficiently. The 15 features with the highest Fisher -coefficient were entered into linear multivariate regression for iterative modeling. Results: Multivariate regression analysis resulted in the best prediction model of the confidence scores after three iterations (df=11, F=11.7, p-value<0.0001). The model predicted scores and human observers were highly correlated (R=0.88, R-sq=0.77). The root-mean-square and maximal residual were 0.21 and 0.44, respectively. The residual scatter plot appeared random, symmetric, and unbiased. Conclusion: For diagnosis of ischemic infarct in non-contrast head CT in adults, the predicted image quality scores from texture analysis-based model observer was highly correlated with that of human observers for various noise levels. Texture-based model observer can characterize image quality of low contrast, subtle texture changes in addition to human observers.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

BBN-simple: How to bake a universe-sized cake

Big Bang Nucleosynthesis (BBN), the process of creation of lightest elements in the early universe, is a highly robust, precise, and ultimately successful theory that forms one of the three pillars of the standard hot-Big-Bang cosmological model. Existing theoretical treatments of BBN and the associated computer codes are accurate and flexible, but are typically highly technical and opaque, and not suitable for pedagogical understanding of the BBN. Here we present BBN-simple - a from-scratch numerical calculation of the lightest element abundances pitched at an advanced undergraduate or beginning graduate level. We review the physics of the early universe relevant for BBN, provide information about the reaction rates, and discuss computational-mathematics background that is essential in setting up a BBN calculation. Here, we calculate the abundances of the principal nuclear species in a standard cosmological model, and find a reasonably good agreement with public precision-level BBN codes.

Big bang nucleosynthesis↗
DOE OSTI2022

Verification and Validation Tests of the Gamma Library of the ARC Software Package (Rev.1)

As part of the verification and validation (V&V) efforts of the Argonne Reactor Code (ARC) software system to support the Versatile Test Reactor (VTR) project of the U.S. Department of Energy (DOE), work has been performed to verify and validate the gamma (or photon) library of the multigroup cross section generation code MC 2 -3 of the ARC system, which is the essential part of the coupled neutron and gamma heating calculations to determine the heat generation rate or power distribution in the core. This V&V study was carried out in three steps: 1) review of the procedures and utility programs for generating the MC 2 -3 gamma library, 2) verification tests of cross sections and KERMA factors by comparing the total heat generation rate of coupled neutron and gamma calculation with that obtained with reaction Q values under the assumption of local gamma energy deposition and by comparing the prompt heat generation rate with that calculated with the MCNP6.2 code, and 3) validation tests of cross sections and KERMA factors by analyzing the ZPPR-15D gamma dose data measured with thermoluminescent dosimeters (TLD).

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Review of Presentation by Carter Wolf

The presentation was informative on the different techniques used to study the electronic dynamics of materials on the femtosecond scale, such as ARPES and TR ARPES. The presentation also discussed in depth code analysis, and the procedure used to remove noise from noisy data via machine learning procedures. The presentation first focused on an overview of the ARPES technique, and how TR-ARPES differs from it. The presentation then explored computational techniques used for fitting ARPES and TR-ARPES data, using the pyARPES framework. After that, the presentation discussed machine learning approaches for denoising noisy data such as Noise2Noise and Noise2Self. The main issue of denoising existing ARPES data and the necessity of machine learning approaches due to the lack of clean ARPES data were very clearly articulated as a major part of the project. The implementation, training and refinement and optimization were clearly detailed, along with a full documentation of attempts that worked and attempts that did not, thus thoroughly and clearly showing the research process. Experimental techniques regarding ARPES were also briefly documented.

36 MATERIALS SCIENCE↗
NASA NTRS2015

PTC MathCAD and Workgroup Manager: Implementation in a Multi-Org System

In this presentation, the presenter will review what was done at Kennedy Space Center to deploy and implement PTC MathCAD and PTC Workgroup Manager in a multi-org system. During the presentation the presenter will explain how they configured PTC Windchill to create custom soft-types and object initialization rules for their custom numbering scheme and why they choose these methods. This presentation will also include how to modify the EPM default soft-type file in the PTC Windchill server codebase folder. The presenter will also go over the code used in a start up script to initiate PTC MathCAD and PTC Workgroup Manager in the proper order, and also set up the environment variables when running both PTC Workgroup Manager and PTC Creo. The configuration.ini file the presenter used will also be reviewed to show you how to set up the PTC Workgroup Manager and customized it to their user community. This presentation will be of interest to administrators trying to create a similar set-up in either a single org or multiple org system deployment. The big take away will be ideas and best practices learned through implementing this system, and the lessons learned what to do and not to do when setting up this configuration. Attendees will be exposed to several different sets of code used and that worked well and will hear some limitations on what the software can accomplish when configured this way.

Multi-Org System↗
DOE OSTI2020

Challenges in the designing, planning and deployment of hydrogen refueling infrastructure for fuel cell electric vehicles

Hydrogen can power transportation with near zero greenhouse gas emissions. With government support, early market development is now underway in several nations thanks to technological advances in fuel cell vehicles and electricity generation from renewable energy. Deploying a sustainable hydrogen refueling infrastructure faces methodological and practical challenges ranging from the creation of appropriate codes to managing the co-evolution of the refueling network and growth of the stock of hydrogen fuel cell vehicles. Furthermore, this paper presents a comprehensive review of the challenges facing the designing, planning and deployment of hydrogen refueling infrastructure progress to date and outlook for the future. The design and costs of refueling infrastructure as well as the lifecycle environmental effects of hydrogen vehicles depend on how hydrogen is produced and delivered to refueling stations. In recent years, important advances have been made in methods for planning the numbers, sizes and location of hydrogen stations. Institutional barriers are also gradually being overcome. Co-evolving the deployment of stations and the demand for fuel cell vehicles remains a crucial subject for future research.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2015

Data Covariances from R-Matrix Analyses of Light Nuclei

After first reviewing the parametric description of light-element reactions in multichannel systems using R-matrix theory and features of the general LANL R-matrix analysis code EDA, we describe how its chi-square minimization procedure gives parameter covariances. This information is used, together with analytically calculated sensitivity derivatives, to obtain cross section covariances for all reactions included in the analysis by first-order error propagation. Examples are given of the covariances obtained for systems with few resonances ({sup 5}He) and with many resonances ({sup 13}C ). We discuss the prevalent problem of this method leading to cross section uncertainty estimates that are unreasonably small for large data sets. The answer to this problem appears to be using parameter confidence intervals in place of standard errors.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

'Edge illumination' in X-ray Phase Contrast Imaging

In the late '90s, the concept of 'edge illumination' was developed at ELETTRA in Italy as an alternative method to increase the phase sensitivity of an imaging system. The main idea was to be able to reproduce the fine angular selection of 'analyzer' crystals without actually using a crystal, as this would allow employing the method with divergent and polychromatic (i.e. conventional) x-ray sources. It was observed that this could be achieved by illuminating only the edges of the detector pixels, and that the method's sensitivity could be progressively increased by illuminating smaller pixel fractions closer to its physical edge. A few years later the idea was adapted for use with a conventional source by means of two sets of x-ray masks ('coded aperture' masks), which enabled obtaining the same effect for each row (or column) of pixels of an area detector illuminated by a cone beam. This article reviews the method and presents recent examples of application.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2012

Simple partitions of a hyperbolic plane of positive curvature

We construct special monohedral isotropic partitions with symmetries of the hyperbolic plane H of positive curvature with a simple 4-contour as a cell. An analogue of mosaic in these partitions called a tiling is introduced. Also we consider some fractal tilings. The existence of band tilings in each homological series with code (m, n) is proved. Bibliography: 14 titles.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2012

THE ROLE OF {theta} OPH IN THE FORMATION AND EVOLUTION OF THE PIPE NEBULA-IS STAR FORMATION EVER ISOLATED?

We propose that the Pipe Nebula is an H II-region shell swept up by the B2 IV {beta} Cephei star {theta} Ophiuchi. After reviewing the morphological evidence from recent observations, we perform a series of analytical calculations. We use realistic H II-region parameters derived with the radiative transfer code Cloudy from observed stellar parameters. We are able to show that the current size, mass, and pressure of the region can be explained in this scenario. We investigate the configuration today and come to the conclusion that the Pipe Nebula can be best described by a three-phase medium in pressure equilibrium. The pressure support is provided by the ionized gas and mediated by an atomic component to confine the cores at the observed current pressure. In the future, star formation in these cores is likely to be either triggered by feedback of the most massive, gravitationally bound cores as soon as they collapse or by the supernova explosion of {theta} Ophiuchi itself.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2012

Consolidated decommissioning guidance: Financial assurance, recordkeeping, and timeliness. Volume 3

The U.S. Nuclear Regulatory Commission (NRC) consolidated and updated numerous decommissioning guidance documents into this three volume NUREG. Specifically, the three volumes address the following topics: (1) "Decommissioning Process for Materials Licensees"; (2) "Characterization, Survey, and Determination of Radiological Criteria"; and (3) "Financial Assurance, Recordkeeping, and Timeliness." This three-volume NUREG series replaces NUREG-1727 ("NMSS Decommissioning Standard Review Plan," issued September 2000) and NUREG/BR-0241 ("NMSS Handbook for Decommissioning Fuel Cycle and Materials Licensees," issued March 1997). This NUREG series is intended for use by NRC staff, licensees, and others. Volume 3 of this NUREG series provides guidance on the technical aspects of compliance with requirements for timeliness in decommissioning of materials facilities, the requirements for financial assurance for decommissioning, and the recordkeeping requirements related to eventual decommissioning. Licensees should use this guidance in preparing decommissioning plans, license termination plans, final status surveys, and other technical decommissioning reports for submittal to the NRC. The NRC staff will use this guidance in reviewing these documents and related license amendment requests. Volume 3 is intended to apply only to the decommissioning of materials facilities licensed under Title 10 of the Code of Federal Regulations (10 CFR) Parts 30, 40, 70, and 72.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Improvements to Bison Validation Base for LWR Fuel

The Bison fuel performance code is being developed by Idaho National Laboratory (INL) to analyze a wide range of fuel forms and operating conditions with the flexibility to conduct simulations in 1D through 3D geometries. Bison plays an important role in the development of advanced fuel with improved accident tolerance for existing light water reactors (LWRs), the improved understanding of mechanisms in fuel designs in a wider range of operating conditions, and the facilitation of future development of fuel for advanced reactor designs. Additionally, industry interest in advanced fuels has also driven Bison development for advanced fuels in the last few years. All of these factors combine to create a potential increase of new Bison users. These new users will potentially be interested in the Bison LWR validation base for examples of Bison's capabilities and how to use Bison. Current users also rely on the Bison validation base as a demonstration of the best practices settings and material behavioral models. Bison, both through direct updates to the Bison source code and to the nearly daily changes and improvements in the underlying MOOSE framework source code, undergoes nearly continuous changes. It is necessary that these source code changes are reflected with updated input files in the Bison validation base. Periodic updates of the validation case input files should also be accompanied by a review and revision of the validation case documentation on which our users rely. Therefore our efforts under this milestone were guided by two objectives: (1) Update the Bison LWR validation input files to use current Bison simulation settings, and (2) Enhance the ease-of-use for Bison through improved documentation These objectives build on the goals identified FY18 CASL milestone reports. During FY18 we addressed issues with the robustness of Bison and identified a need to migrate the assessment suite to the more reliable tensor mechanics module system and set a goal of standardizing the Bison input files. The FY18 CASL milestone report on updates to the Bison documentation system listed continued development of user-focused guides and examples along with revisions to the validation case documentation as future development goals. During FY19 we have separated these two objectives into four different focus areas for our work on this milestone. Our first two focus areas target the existing Bison validation suite: update the existing LWR validation cases and the accompanying documentation. The second two focus areas center on adding new capabilities: a new Bison LWR validation case and expansion of user support documentation. In the following report each of these four focus areas are discussed as a separate section. We conclude the report with a summary of potential future work to build on the efforts of this year.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Fiscal Year 2024 Software Quality Assurance Activities for the ARC Software

The continued goal of the ARC SQA project in the Advanced Reactor Technologies program of DOE is to resolve the QA gaps for the ARC software that limit, or prevent, commercialization of the software for industry users. This project started in earnest in fiscal year 2023 which saw the entire code system moved from a SVN repository to a GitLab repository and an associated software quality assurance plan (SQAP) developed and ratified. Most of the QA gaps in the ARC software were identified in collaboration with industry partners and work begin in fiscal year 2023 and continued in 2024. The primary documentation that is missing includes user manuals, user guides, software verification reports, and code coverage assessments. The SUMMAR manual was completed this fiscal year and work was started on creating manuals for SE2ANL, SE2RCT, and DASSH. Software verification work was carried out for DIF3D and REBUS in a previous program and the current fiscal year saw the completion of software verification reports for GAMSOR, GAMSRC, VARPOW, EvaluateFlux, and SUMMAR. The goal for the next fiscal year is to complete the PERSENT software verification work and begin planning the software verification work for DASSH, SE2ANL, and SE2RCT. The code coverage reports for DIF3D and MC2-3 were completed in the previous fiscal year and the goal is to generate code coverage reports for REBUS, GAMSOR, PERSENT, and DASSH in the coming fiscal year. A considerable amount of effort was spent in the current fiscal year working on the continuous integration capability for automated regression testing in GitLab. The first version of the testing was created in the previous fiscal year and applied to DIF3D and its utility programs. That testing was extended this year to cover GAMSOR, REBUS, and PERSENT. To accomplish this, the first version of the new testing methodology had to be updated to make a single output checking methodology viable for all of the ARC software. This will result in a single document to detail the automated regression testing methodology and minor documents to detail the tolerance settings that have been applied to the output for each ARC code. The previous methodology put into place with SVN would have required a separate document for each ARC code to detail the output checking methodology and the tolerance settings for the output from each code. Because some of our industry partners are providing funds to add new capabilities to the ARC software to meet their needs, all of which must be reviewed and approved by the SQA program funded by this project, a summary of that development work is detailed in this report. Overall progress on resolving the QA gaps has been good this year with the most impactful improvement for our industry partners in capability being the creation of a threaded version of DIF3D-VARIANT that allows the DIF3D, REBUS, and GAMSOR run times to be reduced by a factor of 4-6. The most impactful QA gap that was resolved was the software verification of GAMSRC and VARPOW.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Technical Assessment of the Application of Digital Twin and Prognostic Tools for Condition Monitoring

This report was prepared for the U.S. Nuclear Regulatory Commission (NRC) to present use cases of the application of advanced technologies toward meeting the current and future regulatory requirements for maintenance and condition monitoring of structures, systems, and components (SSCs). The advanced technologies considered in this work, collectively referred to as digital twin (DT) technologies, are advanced sensors and instrumentation, data analytics, machine learning and artificial intelligence (ML/AI), and physics-based models. The report presents two use cases of reactor coolant pumps (RCPs) and heat pipes in nuclear power plants (NPPs) with technical and regulatory considerations and opportunities in using advanced technologies for conditional monitoring. Key findings from the exploration of these considerations are as follows: - Uncertainties in sensor data and model predictions must be rigorously addressed through validation and verification processes - Regulatory compliance is paramount, necessitating data driven models to be developed in line with existing codes and standards, as well as considering potential future guidelines for advanced reactors - Explainability and transparency in ML/AI models are essential for developing operator trust and regulatory review, including methods that enhance the interpretability of complex data-driven predictions - Condition monitoring programs must be evaluated for their effectiveness in reducing maintenance-preventable function failures (MPFF) and aligning with plant performance criteria - The deployment of advanced technologies for condition monitoring could lead to a transition from periodic to continuous monitoring, thereby optimizing maintenance schedules - Collaborative efforts between industry stakeholders, regulatory bodies, and technology developers are crucial for the successful adoption of advanced technologies for condition monitoring systems in nuclear facilities In summary, the introduction of advanced technologies into condition monitoring programs represents a significant leap forward in the domain of NPP maintenance. By harnessing the capabilities of advanced sensors, data analytics, and ML/AI, NPP operators can transition from a time-based to a condition-based maintenance approach. This shift can potentially enhance the reliability and safety of critical plant components while optimizing maintenance efforts and minimizing unnecessary outages. The NRC is continuing to explore the regulatory aspects of advanced technologies as part of inservice inspection and inservice testing (ISI and IST) programs by pursuing additional research in this technical area.

22 - GENERAL STUDIES OF NUCLEAR REACTORS↗