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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 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

An iron evaluation story: from TALYS model parameters to validation on the ASPIS benchmark with the Monte-Carlo code TRIPOLI-4

Iron is a widespread structural material in nuclear applications. However some benchmark studies show that for many libraries, including TENDL-2019, producing good iron evaluations is still an open challenge. This work aims at improving TENDL-2019 {sup 56}Fe and {sup 54}Fe evaluations through feedbacks from experimental data and Monte Carlo results of the iron benchmark ASPIS. Part of the T6 code infrastructure was used to produce the evaluations. In the new evaluations, particular attention to resonance parameters and formalism was paid to address the importance of elastic scattering. The total inelastic scattering and inelastic continuum cross sections were shaped by modifying the input parameters of TALYS, one of the T6 codes. Additionally, it was necessary to normalise some reaction channels to those of JENDL-4.0. With the new files ASPIS results, obtained with the Monte Carlo code TRIPOLI-4, improved noticeably compared to TENDL 2019. The evaluations and parameter setting modifications are to be included into TENDL-2021. (authors)

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Angular dependence of the transverse Raman scattering in KDP and DKDP in geometries suitable for beam polarization control

The angular dependance of the transverse Raman scattering in potassium dihydrogen phosphate (KDP) and its deuterated analogue (DKDP) for the entire range of crystal configurations suitable for laser beam polarization control has been investigated via experimental and modeling tools. This work was made possible by simultaneously rotating a spherical sample and the pump polarization to effectively measure the angular dependance of the transverse Raman signal in 360°. This novel method, which is applicable for the investigation of the Raman scattering in optically anisotropic materials, demonstrates that the spontaneous Raman scattering signal exhibits strong angular dependence that is modulated by depolarization and polarization rotation effects generated as the Raman signal traverses the material due to its birefringence. The results show that the total signal generated by the pump beam is the sum of the signals generated by the two components that have polarization parallel and orthogonal to the optic axis. The peak signal intensity, which is of importance for high-power laser applications, depends on the orientation of the optic axis and can vary by a factor of about 2. The excellent agreement between experimental data and modeling results validates the associated models and enables one to consider optimal crystal cut designs for specific applications.

47 OTHER INSTRUMENTATION↗
DOE OSTI2012

Biowaste to Bioenergy Center - Part 1/5 (DOE SUNY Cobleskill Final Report)

This research evaluated a rotary kiln gasification system utilizing agricultural wastes to generate syn gas. The goal of the project was to develop an efficient methodology for harnessing energy from agricultural waste. Objectives included: installation and cold testing of the gasification system; hot testing the gasification system with two agricultural wastes; development of an operations plan, including a data procurement and analysis plan; development of a predictive model and validation of the model; developing process improvement recommendations; and construction of two deployment pathway models (e.g., institutional and farm).

09 BIOMASS FUELS↗
DOE OSTI2012

Biowaste to Bioenergy Center - Part 2/5 (DOE SUNY Cobleskill Final Report)

This research evaluated a rotary kiln gasification system utilizing agricultural wastes to generate syn gas. The goal of the project was to develop an efficient methodology for harnessing energy from agricultural waste. Objectives included: installation and cold testing of the gasification system; hot testing the gasification system with two agricultural wastes; development of an operations plan, including a data procurement and analysis plan; development of a predictive model and validation of the model; developing process improvement recommendations; and construction of two deployment pathway models (e.g., institutional and farm).

09 BIOMASS FUELS↗
DOE OSTI2012

Biowaste to Bioenergy Center - Part 3/5 (DOE SUNY Cobleskill Final Report)

This research evaluated a rotary kiln gasification system utilizing agricultural wastes to generate syn gas. The goal of the project was to develop an efficient methodology for harnessing energy from agricultural waste. Objectives included: installation and cold testing of the gasification system; hot testing the gasification system with two agricultural wastes; development of an operations plan, including a data procurement and analysis plan; development of a predictive model and validation of the model; developing process improvement recommendations; and construction of two deployment pathway models (e.g., institutional and farm).

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2012

Biowaste to Bioenergy Center - Part 4/5 (DOE SUNY Cobleskill Final Report)

This research evaluated a rotary kiln gasification system utilizing agricultural wastes to generate syn gas. The goal of the project was to develop an efficient methodology for harnessing energy from agricultural waste. Objectives included: installation and cold testing of the gasification system; hot testing the gasification system with two agricultural wastes; development of an operations plan, including a data procurement and analysis plan; development of a predictive model and validation of the model; developing process improvement recommendations; and construction of two deployment pathway models (e.g., institutional and farm).

09 BIOMASS FUELS↗
DOE OSTI2012

Biowaste to Bioenergy Center - Part 5/5 (DOE SUNY Cobleskill Final Report)

This research evaluated a rotary kiln gasification system utilizing agricultural wastes to generate syn gas. The goal of the project was to develop an efficient methodology for harnessing energy from agricultural waste. Objectives included: installation and cold testing of the gasification system; hot testing the gasification system with two agricultural wastes; development of an operations plan, including a data procurement and analysis plan; development of a predictive model and validation of the model; developing process improvement recommendations; and construction of two deployment pathway models (e.g., institutional and farm).

09 BIOMASS FUELS↗
DOE OSTI2013

Beam Characterization at the Neutron Radiography Facility

The quality of a neutron imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam’s effective length-to-diameter ratio, neutron flux profile, energy spectrum, image quality, and beam divergence, is vital for producing quality radiographic images. This project characterized the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam’s effective length-to-diameter ratio and image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. Improvement of the existing NRAD MCNP beamline model includes validation of the model’s energy spectrum and the development of enhanced image simulation methods. The image simulation methods predict the radiographic image of an object based on the foil reaction rate data obtained by placing a model of the object in front of the image plane in an MCNP beamline model.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2015

Experiments to Populate and Validate a Processing Model for Polyurethane Foam: Additional Data for Structural Foams

We are developing computational models to help understand manufacturing processes, final properties and aging of structural foam, polyurethane PMDI. Th e resulting model predictions of density and cure gradients from the manufacturing process will be used as input to foam heat transfer and mechanical models. BKC 44306 PMDI-10 and BKC 44307 PMDI-18 are the most prevalent foams used in structural parts. Experiments needed to parameterize models of the reaction kinetics and the equations of motion during the foam blowing stages were described for BKC 44306 PMDI-10 in the first of this report series (Mondy et al. 2014). BKC 44307 PMDI-18 is a new foam that will be used to make relatively dense structural supports via over packing. It uses a different catalyst than those in the BKC 44306 family of foams; hence, we expect that the reaction kineti cs models must be modified. Here we detail the experiments needed to characteriz e the reaction kinetics of BKC 44307 PMDI-18 and suggest parameters for the model based on these experiments. In additi on, the second part of this report describes data taken to provide input to the preliminary nonlinear visco elastic structural response model developed for BKC 44306 PMDI-10 foam. We show that the standard cu re schedule used by KCP does not fully cure the material, and, upon temperature elevation above 150°C, oxidation or decomposition reactions occur that alter the composition of the foam. These findings suggest that achieving a fully cured foam part with this formulation may be not be possible through therma l curing. As such, visco elastic characterization procedures developed for curing thermosets can provide only approximate material properties, since the state of the material continuously evolves during tests.

36 MATERIALS SCIENCE↗
DOE OSTI2015

A Kinetic Approach to Modeling the Manufacture of High Density Polyurethane Structural Foam: Foaming and Polymerization

This report details the study of PMDI structural foam and the development of a computational model to represent it. This polyurethane has a fast catalyst, such that foaming and polymerization occur simultaneously. The foam is over-packed to twice or more of its free rise density to reach the density of interest. Our approach is to combine model development closely with experiments to discover underlying physical phenomena, to parameterize models, and to validate the models once they have been developed. The model must be able to represent the expansion, filling of molds, curing, and final foam properties. PMDI is a chemically blown foam, where carbon dioxide is produced via the reaction of water and isocyanate. The isocyanate also reacts with polyol in a competing reaction, which produces the polymer. A new kinetic model is developed and implemented, which follows a simplified mathematical formalism that decouples these two reactions. The model predicts the polymerization reaction via condensation chemistry, where vitrification and glass transition temperature evolution must be included to correctly predict the temperature dependence of the kinetics. The foam gas generation kinetics are determined by tracking the molar concentration of both water and carbon dioxide. Understanding the thermal history and loads on the foam due to exothermicity and oven curing is very important to the results, since the kinetics and material properties are all sensitive to temperature. The conservation equations, including the equations of motion, an energy balance, and three rate equations are solved via a stabilized finite element method. We assume generalized-Newtonian rheology that is dependent on the extent of cure, gas fraction, and temperature. The conservation equations are combined with a level set method to determine the location of the free surface over time. Results from the model are compared to experimental flow visualization data and post-test X-ray computed tomography (CT) data for the density. Several geometries are investigated including a mock encapsulation part, two configurations of a mock structural part, and a bar geometry to specifically test the density model. We have found that the model predicts both average density and filling profiles well. However, it under predicts density gradients, especially in the gravity direction. Further model improvements are also discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Thermal transport in UO 2 with defects and fission products by molecular dynamics simulations

The importance of the thermal transport in nuclear fuel has motivated a wide range of experimental and modelling studies. In this report, the reduction of thermal transport in UO 2 due to defects and fission products has been investigated using non-equilibrium MD simulations, with two sets of empirical potentials for studying the degregation of UO 2 thermal conductivity including a Buckingham type interatomic potential and a recently developed EAM type interatomic potential. Additional parameters for U 5+ and Zr 4+ in UO 2 have been developed for the EAM potential. The thermal conductivity results from MD simulations are then corrected for the spin-phonon scattering through Callaway model formulations. To validate the modelling results, comparison was made with experimental measurements on single crystal hyper-stoichiometric UO 2+x samples.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

3D-FE Modeling of 316 SS under Strain-Controlled Fatigue Loading and CFD Simulation of PWR Surge Line

In financial year 2017, we are focusing on developing a mechanistic fatigue model of surge line pipes for pressurized water reactors (PWRs). To that end, we plan to perform the following tasks: (1) conduct stress- and strain-controlled fatigue testing of surge-line base metal such as 316 stainless steel (SS) under constant, variable, and random fatigue loading, (2) develop cyclic plasticity material models of 316 SS, (3) develop one-dimensional (1D) analytical or closed-form model to validate the material models and to understand the mechanics associated with 316 SS cyclic hardening and/or softening, (4) develop three-dimensional (3D) finite element (FE) models with implementation of evolutionary cyclic plasticity, and (5) develop computational fluid dynamics (CFD) model for thermal stratification, thermal-mechanical stress, and fatigue of example reactor components, such as a PWR surge line under plant heat-up, cool-down, and normal operation with/without grid-load-following. This semi-annual progress report presents the work completed on the above tasks for a 316 SS laboratory-scale specimen subjected to strain-controlled cyclic loading with constant, variable, and random amplitude. This is the first time that the accurate 3D-FE modeling of the specimen for its entire fatigue life, including the hardening and softening behavior, has been achieved. We anticipate that this work will pave the way for the development of a fully mechanistic-computer model that can be used for fatigue evaluation of safety-critical metallic components, which are traditionally evaluated by heavy reliance on time-consuming and costly test-based approaches. This basic research will not only help the nuclear reactor industry for fatigue evaluation of reactor components in a cost effective and less time-consuming way, but will also help other safety-related industries, such as aerospace, which is heavily dependent on test-based approaches, where a single full-scale fatigue test can cost millions of dollars and require years of effort to conduct. Toward our goal of demonstration of fully mechanistic fatigue evaluation of reactor components, we also started work on developing a component-level computer model of reactor components, such as 316 SS surge line pipe. This requires developing a thermal-mechanical stress analysis model of the reactor surge line, which, in turn, requires time-dependent temperature and stratification information along the boundary of the pipe. Toward that goal, CFD models of surge lines are being developed. In this report, we also present some preliminary results showing the temperature conditions along the surge line wall under reactor heat-up, cool-down, and steady-state power operation.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

DNV GL Joint Industry Project on Validation of Turbulence Models

This shared resource CRADA defines research collaborations between the National Renewable Energy Laboratory (NREL) and Det Norske Veritas (Norway) and Germanischer Lloyd (Germany), known as DNV GL, an international certification body. Under the terms and conditions described in this CRADA agreement, NREL will participate in a wind turbine Joint Industry Project (JIP) led by DNV GL, and including nine other Joint Industry Project sponsors and partners to examine the wind inflow models needed to define the design conditions for wind turbines, with specific focus on atmospheric turbulence. The international design standards are implemented by certification companies, such as DNV GL, the organizing agent of the JIPs. Through this collaboration, the JIP participants have the ability to improve wind turbine design, internationally, as well as in the United States, and can make this improvement by leveraging the significant aggregation of industry funds that has been organized by DNV GL.

17 WIND ENERGY↗
DOE OSTI2023

Tech-X contributions to the Center for Tokamak Transients (CTTS) Scientific Discovery through Advanced Computing (SciDAC) project (Final Report)

The Center for Tokamak Transients Simulations (CTTS) consists of computational plasma physicists, computer scientists, and applied mathematicians who are together developing and applying simulation software to improve our understanding of and ability to predict and control transient events in tokamak discharges, particularly those that lead to violent disruptions. We have major simulation activities concerning disruptions that are caused by violating ideal MHD stability criteria, vertical displacement events, resistive wall modes, and tearing modes. We are performing comprehensive modeling of disruption mitigation techniques, particularly by shattered pellet injection (SPI). The Center is built around two mature extended MHD codes: NIMROD and M3D-C1. These codes are being extended in a number of ways as required by the demands of disruption modeling, and are being optimized to work well for larger problem size and modern computer architectures as required to model tokamak plasmas with realistic parameters over the required timescales. The codes will be coupled to the FronTier code for state-of-the-art modeling of SPI. Validation with experimental data on DIII-D, NSTX, and JET is being facilitated by rigorous uncertainty quantification (UQ). The high-level objectives of the center are to: (1) Develop better understanding and improved predictive capability of when crossing a linear stability boundary will likely lead to a disruption, (2) Provide a tool for calculating vessel forces, both axisymmetric and non-axisymmetric, for worst case VDE and other disruptions in tokamaks, (3) Develop increased understanding and improved predictive capability for locked mode disruptions and how best to avoid them, (4) Develop, verify, and validate 3D models for disruption mitigation by shattered pellets that can be used to design and optimize a system for future tokamaks, and (5) Increase the efficiency and scalability of the M3D-C1 and NIMROD codes so that they can model disruptions in ITER scale devices using the most powerful DOE HPC hardware, and (6) Demonstrate code-coupling via FronTier coupling with NIMROD and M3D-C1 and by interfacing these codes within a WDM framework.

97 MATHEMATICS AND COMPUTING↗