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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 1,711 records · Page 95
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

MICROX-2 cross section library based on ENDF/B-VII

New cross section libraries of a neutron transport code MICROX-2 have been generated for advanced reactor design and fuel cycle analyses. A total of 386 nuclides were processed, including 10 thermal scattering nuclides, which are available in ENDF/B-VII release 0 nuclear data. The NJOY system and MICROR code were used to process nuclear data and convert them into MICROX-2 format. The energy group structure of the new library was optimized for both the thermal and fast neutron spectrum reactors based on Contributon and Point-wise Cross Section Driven (CPXSD) method, resulting in a total of 1173 energy groups. A series of lattice cell level benchmark calculations have been performed against both experimental measurements and Monte Carlo calculations for the effective/infinite multiplication factor and reaction rate ratios. The results of MICROX-2 calculation with the new library were consistent with those of 15 reference cases. The average errors of the infinite multiplication factor and reaction rate ratio were 0.31% {delta}k and 1.9%, respectively. The maximum error of reaction rate ratio was 8% for {sup 238}U-to-{sup 235}U fission of ZEBRA lattice against the reference calculation done by MCNP5. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

New technique to reformat multigroup cross-sections for Monte-Carlo calculation

New method to calculate equi-probability bins from Legendre expansion scattering cross-sections is proposed. The method uses correction of equi-probability bins boundaries to provide conservation of the first angular moment. CRSRD-ST code is developed to reformat cross sections from DTF to ACE format using proposed technique. Numerical results show that the proposed method significantly improves agreement between deterministic and Monte-Carlo calculations. (authors)

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

GRAPhEME: a setup to measure (n, xn γ) reaction cross sections

Most of nuclear reactor developments are using evaluated data base for numerical simulations. However, the considered databases present still large uncertainties and disagreements. To improve their level of precision, new measurements are needed, in particular for (n, xn) reactions, which are of great importance as they modify the neutron spectrum, the neutron population, and produce radioactive species. The IPHC group started an experimental program to measure (n, xn gamma) reaction cross sections using prompt gamma spectroscopy and neutron energy determination by time of flight. Measurements of (n, xn gamma) cross section have been performed for {sup 235,238}U, {sup 232}Th, {sup nat,182,183,184,186}W, {sup nat}Zr. The experimental setup is installed at the neutron beam at GELINA (Geel, Belgium). The setup has recently been upgraded with the addition of a highly segmented 36 pixels planar HPGe detector. Significant efforts have been made to reduce radiation background and electromagnetic perturbations. The setup is equipped with a high rate digital acquisition system. The analysis of the segmented detector data requires a specific procedure to account for cross signals between pixels. An overall attention is paid to the precision of the measurement. The setup characteristic and the analysis procedure will be presented along with the acquisition and analysis challenges. Examples of results and their impact on models will be discussed. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

use of cross-section covariance information in uncertainty analysis at modeling HTGR neutron physics - 18551

This work is aimed at improvement of high temperature gas cooled reactors (HTGR) neutron physics design calculations by application of uncertainty analysis with the use of cross-section covariance information. Methodology and codes for preparation of multigroup libraries of covariance information for individual isotopes from the basic 44-group binary library of SCALE-6 code system were developed. A 69-group library of covariance information in a special format for main isotopes and elements typical for HTGR was generated. This library can be used for estimation of uncertainties associated with nuclear data in analysis of HTGR neutron physics with design codes. As an example, calculations of one-group cross-section uncertainties for fission and capture reactions for main isotopes of the MHTGR-350 benchmark, as well as uncertainties of the multiplication factor (k{sub ∞}) for the MHTGR-350 fuel compact cell model and fuel block model were performed. These uncertainties were estimated by the developed technology with the use of WIMS-D code (technology SUW) and modules of SCALE-6 code system, namely, by TSUNAMI, KENO-VI and SAMS. The eight most important reactions on isotopes for MHTGR-350 benchmark were identified, namely: {sup 10}B(capt), {sup 238}U(n,γ), ν{sub 5}, {sup 235}U(n,γ), {sup 238}U(el), {sup nat}C(el), {sup 235}U(fiss)-{sup 235}U(n,γ) and {sup 235}U(fiss). It is shown that the main contribution in the uncertainty of multiplication factor of the fuel block model gives the reaction {sup 10}B(capt) ((n,α)+(n,γ)). (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2015

Capture Cross Section Measurements in {sup nat}Fe and {sup 181}Ta from 1 to 2000 keV Using a New C6D6 Detector Array

A new array of four C6D6 detectors has been developed at the Rensselaer Polytechnic Institute Gaerttner LINAC center for the purposes of measuring neutron capture cross sections in the keV resonance region with low sensitivity to scattered neutrons. The new detection apparatus incorporates low-mass, low cross-section materials to reduce neutron sensitivity, and uses digital data acquisition equipment to enable saving of the full waveform output of each detector module for offline analysis. Capture yields are determined by applying the total energy method and pulse height weighting technique during the analysis of the saved data. Measurements have been performed on samples of iron and tantalum using the new system, with results consistent with existing data libraries. (authors)

42 ENGINEERING↗
DOE OSTI2015

Evaluated {sup 182,183,184,186}W neutron cross sections and covariances in the resolved resonance region - 14617

Oak Ridge National Laboratory (ORNL) has recently completed the resonance parameter evaluation of four tungsten isotopes, i.e., {sup 182,183,184,186}W, in the neutron energy range of thermal up to several keV. This nuclear data work was performed with support from the US Nuclear Criticality Safety Program (NCSP) in an effort to provide improved tungsten cross section and covariance data for criticality safety analyses. The evaluation methodology uses the Reich-Moore approximation of the R-matrix formalism of the code SAMMY to fit high-resolution measurements performed in 2010 and 2012 at the Geel linear accelerator facility (GELINA), as well as other experimental data sets on natural tungsten available in the EXFOR library. In the analyzed energy range, this work nearly doubles the resolved resonance region (RRR) present in the latest US nuclear data library ENDF/B-VII.1. In view of the interest in tungsten for distinct types of nuclear applications and the relatively homogeneous distribution of the isotopic tungsten - namely, {sup 182}W(26.5%), {sup 183}W(14.31%), {sup 184}W(30.64%), and {sup 186}W(28.43%) - the completion of these four evaluations represents a significant contribution to the improvement of the ENDF library. This paper presents an overview of the evaluated resonance parameters and related covariances for total and capture cross sections on the four tungsten isotopes. (authors)

42 ENGINEERING↗
DOE OSTI2023

ASME Section III

This presentation is for ASME Section III at University of Tennessee Student Event on October 18, 2023. Includes ASME Section III - Rules for construction of nuclear facility components, including an all-inclusive term that includes material, design, fabrication, installation, examination, testing, overpressure protection, inspection, stamping, and certification, and discusses Division 1-5.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

FLASSH 1.0: Thermal scattering law evaluation and cross section generation for reactor physics applications

The Full Law Analysis Scattering System Hub (FLASSH) is a modern, advanced code which evaluates the thermal scattering law (TSL) along with accompanying cross sections. FLASSH features generalized methods which accommodate any material structure. Historical approximations including the incoherent and cubic approximations have been removed. Instead, the latest release of FLASSH features advanced physics options including distinct corrections (1-phonon contributions) and non-cubic formulations. The non-cubic elastic and inelastic contributions are necessary to accurately evaluate 1-phonon contributions. Both non-cubic and 1-phonon calculations require high-density sampling of the various scattering directions. Optimization and parallelization of these routines were therefore necessary to produce results in a reasonable timeframe. With these notable improvements to the generalized TSL, FLASSH 1.0 meets benchmark requirements, demonstrating noticeable agreement with experiment for both TSLs and the resulting integrated cross sections. Additional features including a graphical user interface (GUI), plotting diagnostics, and formatted output options including ACE files allow users to complete a TSL evaluation with minimal input and maximum flexibility. The user GUI creates input files for FLASSH, reducing user error and also providing built-in error checks. Autofill options and suggested input values help make TSL evaluation accessible to novice users. The FLASSH code is compiled to run on both Windows and Linux platforms with automatic parallelization. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2022

Bayesian estimation of cross-section and errors of experiment and calculation for accurate prediction of neutronic characteristics

In some experiments, there might be a correlation of experimental errors such as an error caused by fabrication. The correlation of calculation errors also might exist among analyses of experiments. In the present study, considering these correlations, the cross-section and errors of experiment and calculation are adjusted for the accurate prediction of neutronic characteristics. The adjustment method is derived based on Bayesian theory. The 'a posteriori' distributions of cross-section and errors of experiment and calculation are obtained by the derivation. The case study is performed by using the benchmarks of light-water moderated experiments reported in ICSBEP. The error from fuel rod fabrication and measurement are included in the experiment error, and the error from the simplification of the benchmark model is included in the calculation error. Since these errors have a positive correlation among the benchmarks, the prediction accuracy is expected to be improved by considering these correlations. For the sensitivity analysis of the correlation among benchmarks, the correlation coefficient of experiment error and that of calculation error is assumed from 0.0 to 0.9. The results indicate that the prediction accuracy of the multiplication factor can be improved by increasing the correlation coefficient of experiment error and that of calculation error. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2024

Guidance on EPAct section 707 Emergency Repair and Restoration Vehicle Exclusions: EPAct State and Alternative Fuel Provider Fleet Program Guidance Document

Section 707 of the Energy Policy Act of 2005 (EPAct 2005) amended section 301(9)(E) of EPAct 1992 by adding to the list of vehicles excluded from the definition of "fleet" a new subcategory of emergency motor vehicles, i.e., "vehicles directly used in the emergency repair of transmission lines and in the restoration of electricity service following power outages, as determined by the Secretary." Like other excluded vehicles, these light-duty vehicles (LDVs) do not count (1) when determining whether a fleet is covered under the U.S. Department of Energy's (DOE) State and Alternative Fuel Provider Fleet Program (Program), and (2) for fleets that are covered under the Program, when calculating annual alternative fuel vehicle (AFV)-acquisition requirements. If AFV models of excluded vehicles are acquired, however, a fleet may count them toward their acquisition requirement by including them in the calculation of the number of AFVs acquired. Exclusion Process.

ADVANCED PROPULSION SYSTEMS,ENERGY PLANNING, POLIC↗
DOE OSTI2012

Analysis of Chloroquine and Metabolites Directly from Whole-body Animal Tissue Sections by Liquid Extraction Surface Analysis (LESA) and Tandem Mass Spectrometry

The rapid and direct analysis of the amount and spatial distribution of exogenous chloroquine and chloroquine metabolites from tissue sections by liquid extraction surface sampling analysis coupled with tandem mass spectrometry (LESA-MS) was demonstrated. LESA-MS results compared well with previously published chloroquine quantification data collected by organ excision, extraction and fluorescent detection. The ability to directly sample and analyze spatially-resolved exogenous molecules from tissue sections with minimal sample preparation and analytical method development has the potential to facilitate the assessment of target tissue penetration of pharmaceutical compounds, to establish pharmacokinetic/pharmacodynamic (PK/PD) relationships, and to complement established pharmacokinetic methods used in the drug discovery process during tissue distribution assessment.

chloroquine↗
DOE OSTI2015

Absolute photoionization cross sections of furanic fuels: 2‐ethylfuran, 2‐acetylfuran and furfural

Absolute photoionization cross sections of the molecules 2‐ethylfuran, 2‐acetylfuran and furfural, including partial ionization cross sections for the dissociative ionized fragments, are measured for the first time. These measurements are important because they allow fuel quantification via photoionization mass spectrometry and the development of quantitative kinetic modeling for the complex combustion of potential fuels. The experiments are carried out using synchrotron photoionization mass spectrometry with an orthogonal time‐of‐flight spectrometer used for mass analysis at the Advanced Light Source of Lawrence Berkeley National Laboratory. The CBS‐QB3 calculations of adiabatic ionization energies and appearance energies agree well with the experimental results. Several bond dissociation energies are also derived and presented. Copyright © 2015 John Wiley & Sons, Ltd.

Smith, Audrey R.↗
DOE OSTI2017

Solid-State Joining of Thick-Section Dissimilar Materials using a New Friction Stir Dovetailing (FSD) Process

Solid-state joining of thick section aluminum to steel plate has been achieved using a new process called Friction Stir Dovetailing (FSD). In FSD, a custom designed pin tool is used to flow a lower melting point material (AA6061) into dovetail grooves machined into the surface of an underlying higher melting point material (Rolled Homogeneous Armor – RHA). Repeating dovetails form a mechanical interlocking structure akin to metallic Velcro. In this study, AA6061 sections ranging in thickness from 1.5” to 3.0” are joined to 0.5” thick RHA plates. The effectiveness of FSD is demonstrated through tensile test data which shows specimens failing in the processed aluminum rather than at the joint interface. Numerical simulations are presented which highlight the importance of optimizing dovetail geometry. The effect of process parameters on joint strength, microstructure, and hardness are also discussed.

dissimilar metals joining↗
DOE OSTI2013

Measurement of the ZZ production cross section and search for anomalous couplings in 2ℓ2ℓ' final states in pp collisions at $ \sqrt{s}=7 $ TeV

A measurement is presented of the ZZ production cross section in the ZZ to 2l 2l' decay mode with l = e, mu and l' = e, mu, tau in proton-proton collisions at sqrt(s) = 7 TeV with the CMS experiment at the LHC. Results are based on data corresponding to an integrated luminosity of 5.0 inverse femtobarns. The measured cross section sigma(pp to ZZ) = 6.24 [+0.86/-0.80] (stat.) [+0.41/-0.32] (syst.) +/- 0.14 (lumi.) pb is consistent with the standard model predictions. The following limits on ZZZ and ZZ gamma anomalous trilinear gauge couplings are set at 95% confidence level: -0.011 < f[4;Z] < 0.012, -0.012 < f[5;Z] < 0.012, -0.013 < f[4;gamma] < 0.015, and -0.014 < f[5,gamma] < 0.014.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Measurement of the tt¯ production cross-section as a function of jet multiplicity and jet transverse momentum in 7 TeV proton-proton collisions with the ATLAS detector

The t t &#x00AF;<!-- ¯ --> production cross-section dependence on jet multiplicity and jet transverse momentum is reported for proton-proton collisions at a centre-of-mass energy of 7 TeV in the single-lepton channel. This data was collected with the ATLAS detector at the CERN Large Hadron Collider and comprise the full 2011 data sample corresponding to an integrated luminosity of 4.6 fb –1 . Differential cross-sections are presented as a function of the jet multiplicity for up to eight jets using jet transverse momentum thresholds of 25, 40, 60, and 80 GeV, and as a function of jet transverse momentum up to the fifth jet. The results are shown after background subtraction and corrections for all known detector effects, within a kinematic range closely matched to the experimental acceptance. Several QCD-based Monte Carlo models are compared with the results. Sensitivity to the parton shower modelling is found at the higher jet multiplicities, at high transverse momentum of the leading jet and in the transverse momentum spectrum of the fifth leading jet. As a result, the MC@NLO+HERWIG MC is found to predict too few events at higher jet multiplicities.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Measurement of the cross-section for producing a W boson in association with a single top quark in pp collisions at $\sqrt{s}=13 $ TeV with ATLAS

The inclusive cross-section for the associated production of a W boson and top quark is measured using data from proton-proton collisions at s√=13 TeV. The dataset corresponds to an integrated luminosity of 3.2 fb -1 , and was collected in 2015 by the ATLAS detector at the Large Hadron Collider at CERN. Events are selected requiring two opposite sign isolated leptons and at least one jet; they are separated into signal and control regions based on their jet multiplicity and the number of jets that are identified as containing b hadrons. The W t signal is then separated from the $t\bar{t}$ background using boosted decision tree discriminants in two regions. The cross-section is extracted by fitting templates to the data distributions, and is measured to be σ W t =94 ± 10(stat.) -22 +28 (syst.)±2(lumi.) pb. Lastly, the measured value is in good agreement with the SM prediction of σ theory = 71.7±1.8 (scale)± 3.4 (PDF) pb.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Measurements of top-quark pair single- and double-differential cross-sections in the all-hadronic channel in pp collisions at $ \sqrt{\mathrm{s}} $ = 13 TeV using the ATLAS detector

Differential cross-sections are measured for top-quark pair production in the all-hadronic decay mode, using proton-proton collision events collected by the ATLAS experiment in which all six decay jets are separately resolved. Absolute and normalised single- and double-differential cross-sections are measured at particle and parton level as a function of various kinematic variables. Emphasis is placed on well-measured observables in fully reconstructed final states, as well as on the study of correlations between the top-quark pair system and additional jet radiation identified in the event. The study is performed using data from proton-proton collisions at s = 13 TeV collected by the ATLAS detector at CERN’s Large Hadron Collider in 2015 and 2016, corresponding to an integrated luminosity of 36.1 fb - 1 . The rapidities of the individual top quarks and of the top-quark pair are well modelled by several independent event generators. Significant mismodelling is observed in the transverse momenta of the leading three jet emissions, while the leading top-quark transverse momentum and top-quark pair transverse momentum are both found to be incompatible with several theoretical predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Differential cross-section measurements of the production of four charged leptons in association with two jets using the ATLAS detector

Differential cross-sections are measured for the production of four charged leptons in association with two jets. These measurements are sensitive to final states in which the jets are produced via the strong interaction as well as to the purely-electroweak vector boson scattering process. The analysis is performed using proton-proton collision data collected by ATLAS at $\sqrt{s}$ = 13 TeV and with an integrated luminosity of 140 fb –1 . The data are corrected for the effects of detector inefficiency and resolution and are compared to state-of-the-art Monte Carlo event generator predictions. The differential cross-sections are used to search for anomalous weak-boson self-interactions that are induced by dimension-six and dimension-eight operators in Standard Model effective field theory.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗