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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 1,135 records · Page 63
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Quasi-differential neutron induced neutron emission reaction measurements at WNR

The quasi-differential neutron induced neutron emission reaction measurement (QD-NINE) method provides an additional benchmark which constrains cross-section evaluations and provides a measure of verification for existing evaluations. Experiments are preformed using an array of EJ-309 liquid scintillators at a variety of angles measuring the neutron scattering response from a sample.. An MCNP simulation is then compared to this experimental data and is run using various sets of evaluated nuclear data. Since the isotopes of interest for this measurement, {sup 235}U and {sup 239}Pu, are difficult to obtain, the WNR facility at LANL was chosen to perform the measurements utilizing the chi-nu detector array. A measurement of carbon has been performed and the high energy cutoff has been extended from 20 to 60 MeV compared with previous measurements using this method. An early stage simulation was compared to the experimental data and the results show good agreement. (authors)

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2014

Sensitivity Analysis and Data Assimilation in a Subcritical Plutonium Metal Benchmark

Here, this work presents the application of first-order adjoint sensitivity analysis, uncertainty quantification, and data assimilation to a subcritical plutonium benchmark experiment using a modified version of the discrete ordinates radiation transport code Denovo. Previous Monte Carlo simulations of this benchmark saw a consistent overprediction of the mean and variance of the measured neutron multiplicity distribution. It was observed that a small scalar reduction in the value of the 239 Pu-induced fission neutron multiplicity was capable of significantly reducing the discrepancies. This work extends those results by computing first-order sensitivities to each nuclide, reaction type, energy, and material region in the benchmark. The sensitivities are then used in a data assimilationmethodology to simultaneously calibrate all responses and multigroup nuclear data. The resulting best-estimate values for the energy group differential multiplicity $\bar{v}$(E g ) are 1σ to 2σ less than the nominal values found in ENDF/B-VII for energies less than 1.5 MeV.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2015

A New Module for Large Scale Bayesian Evaluation in the Fast Neutron Energy Region

We present an improved update scheme for the Linearized Bayesian Update procedure (LBUP). The revised procedure extends the application of the LBUP to a large number of observables. The consistent update of dozens of millions of observables becomes manageable by circumventing the costly calculation of the prior covariance matrix. Nuclear data evaluations based on the revised scheme may exhaustively enclose all differential and angle-integrated channels, treating all correlations between them exactly in the update procedure.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Data Integration Aggregated Model For Nuclear Deployment

The data of a nuclear utility or plant are stored in various isolated forms in different systems. These data have different structures and tools and are, therefore, used independently. The integration of data sources is often needed and is performed manually and on an as-needed basis. The integration of the data would enable creating a data warehouse for a single nuclear power plant (NPP) or multiple plants. A data model contains objects that make up a given domain along with their attributes and relationships and could be used as a standard for exchange between applications for simple integration and data aggregation. After a survey of existing models, it was determined that a new model was required to meet the scope of this problem. DIAMOND has been developed in the form of an ontology to meet these needs. An ontology is simply a data model that also acts as a taxonomy for the domain, organizing the objects in a hierarchy with the most general objects at the top.

Browning, JerenM↗
DOE OSTI2021

Measurement and modeling of proton-induced reactions on arsenic from 35 to 200 MeV

72 As is a promising positron emitter for diagnostic imaging that can be employed locally using a 72 Se generator. However, current reaction pathways to 72 Se have insufficient nuclear data for efficient production using regional 100–200 MeV high-intensity proton accelerators. In order to address this deficiency, stacked-target irradiations were performed at LBNL, LANL, and BNL to measure the production of the 72 Se/ 72 As positron emission tomography (PET) generator system via 75 As (p, x) between 35 and 200 MeV. This work provides the most well-characterized excitation function for 75 As ( p , 4 n ) 72 Se starting from threshold. Additional focus was given to report the first measurements of 75 As (p, x) 68 Ge and bolster an already robust production capability for the highly valuable 68 Ge/ 68 Ga PET generator. Thick target yield comparisons with prior established formation routes to both generators are made. In total, high-energy proton-induced cross sections are reported for 55 measured residual products from 75 As, nat Cu , and nat Ti targets, where the latter two materials were present as monitor foils. These results were compared with literature data as well as the default theoretical calculations of the nuclear model codes TALYS, COH, EMPIRE, and ALICE. Reaction modeling at these energies is typically unsatisfactory due to few prior published data and many interacting physics models. Therefore, a detailed assessment of the talys code was performed with simultaneous parameter adjustments applied according to a standardized procedure. Particular attention was paid to the formulation of the two-component exciton model in the transition between the compound and preequilibrium regions, with a linked investigation of level density models for nuclei off of stability and their impact on modeling predictive power. This paper merges experimental work and evaluation techniques for high-energy charged-particle isotope production in an extension to an earlier study of this kind.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

AGR-2 Data Qualification Report for ATR Cycle 154B

This report provides the data qualification status of Advanced Gas Reactor-2 (AGR-2) fuel irradiation experimental data from Advanced Test Reactor (ATR) Cycle 154B as recorded in the Nuclear Data Management and Analysis System (NDMAS). This is the last cycle of AGR-2 irradiation, as the test train was pulled from the ATR core during the outage portion of ATR Cycle 155A. The AGR-2 data streams addressed in this report include thermocouple (TC) temperatures, sweep gas data (flow rates including new Fission Product Monitoring (FPM) downstream flows from Fission Product Monitoring System (FPMS) detectors, pressure, and moisture content), and FPMS data (release rates and release-to-birth rate ratios [R/Bs]) for each of the six capsules in the AGR-2 experiment. The final data qualification status for these data streams is determined by a Data Review Committee (DRC) comprised of AGR technical leads, Sitewide Quality Assurance (QA), and NDMAS analysts. The Data Review Committee reviewed the data acquisition process, considered whether the data met the requirements for data collection as specified in QA-approved Very High Temperature Reactor (VHTR) data collection plans, examined the results of NDMAS data testing and statistical analyses, and confirmed the qualification status of the data as given in this report.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

High-resolution neutron time-of-flight measurements for light water at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory

Series of light water inelastic neutron scattering experiments have been made at the Oak Ridge National Laboratory (ORNL), Spallation Neutron Source (SNS) covering temperatures ranging from 295 K to 600 K and pressures of 1 bar and 150 bar. The temperatures and pressures ranges correspond to that of pressurized light water reactors. The inelastic scattering measurements will help the development of light water thermal scattering kernels, also known as S (α,β) thermal scattering law (TSL), in a consistent fashion given the amount and the quality of the measured data. Light water thermal scattering evaluations available in existing nuclear data libraries have certain limitations and pitfalls. This paper introduces the state of the art of the light water thermal scattering cross-section data not only for room temperature but as well as for reactor operating temperatures, i.e. 550 - 600 K. During the past few years there has been a renewed interest in re-investigating the existing TSL models and utilize the recent experimental data or perform molecular dynamics simulations. It should be pointed out that no single TSL evaluation is based entirely on experimental data and one has to rely on TSL models or a combination of both. New TOF measurement of light water at the SNS, with a detailed description of the experimental setup, measurement conditions, and the associated foreseen results is presented in this paper. The analysis of the experimental data would help in validating the existing approach based on old experimental data or based on molecular dynamic simulations using classical water models, knowledge of which is very important to generate TSL libraries at reactor operating conditions.

Leal, Luiz C.↗
DOE OSTI2023

Nuclear Structure and Decay Data for A=71 Isobars

Experimental nuclear spectroscopic data are evaluated for 12 known nuclides of mass number=71 (Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Kr). Detailed compiled and evaluated information is presented for each reaction and decay experiment. The β – n decay of 72 Co to 71 Ni is included in this work, while for β – n decay of 71 Co to 70 Ni, consult Nuclear Data Sheets for A=70 (2016Gu11) or the ENSDF database for 70 Ni. Combining all the available data, recommended values are provided for energies, spins and parities, and half-lives of levels, with energies, branching ratios and multipolarities of γ radiations, and characteristics of β and α radiations in radioactive decays. Excited-states have not yet been identified in 71 Mn, 71 Fe, and 71 Kr, with the ground-state half-life remaining unknown only for 71 Mn; data for excited states in 71 Co and 71 Ni are very limited; 71 Ga, 71 Ge and 71 As are the most extensively studied nuclides via various reactions and decays, followed by 71 Cu, 71 Zn, 71 Se, and 71 Br, however, except for 71 Ge, the decay schemes of all other nuclides are considered as incomplete due to a large gap between the decay Q-value and the highest observed level. Lastly, this work supersedes earlier evaluations of A=71 by 2011Ab01.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Nuclear Structure and Decay Data for A=167 Isobars

Experimental nuclear spectroscopic data are compiled and evaluated for 17 known nuclides of mass 167 (Sm, Eu, Gd, Tb, Dy, Ho, Er Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt), 23 years after the previous full evaluation by 2000Ba65. Detailed information is presented for each reaction and decay experiment. Combining all the available data, recommended values are provided for energies, spins and parities, and half-lives of levels, with energies, branching ratios and multipolarities of γ radiations, and characteristics of β and α radiations in radioactive decays. Here, the α decays of A=171 nuclei to A=167 daughters are included in this work, while for α decays of A=167 nuclei to A=163 daughters, consult Nuclear Data Sheets (2010Re03) or the ENSDF database for A=163. 167 Er, 167 Tm, 167 Yb, 167 Lu and 167 Ta are among the most extensively studied nuclides via decay and high-spin gamma-ray spectroscopy measurements, followed by 167 Ho, 167 Hf, 167 W, and 167 Os. Information for excited states in 167 Dy, 167 Re, and 167 Ir are limited; no excited states have yet been identified in 167 Sm, 167 Eu, 167 Gd, 167 Tb and 167 Pt, with the ground-state half-life of 167 Sm remaining unknown. This work supersedes the earlier evaluation of A=167 nuclei by 2000Ba65.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

General Interaction Data Interface

The General Interaction Data Interface (GIDI) is a C++ API that reads and writes nuclear reaction data stored in the General Nuclear Data Structure (GNDS). GNDS is a new "format" for storing nuclear reaction data developed by the Working Party on Evaluation Co-operation (OECD/NEA/WPEC) Subgroup 38. GNDS can store evaluated nuclear data as well as nuclear data processed for deterministic (multi-group) and Monte Carlo transport. GIDI handles and provides accesses to all forms of the GNDS nuclear data. For multi-group data, GIDI provides functions to sum the data over all reactions. It also has functions for collapsing multi-group data to a small subset of groups and can transport correct multi-group data using the Pendlebury/Underhill formalism. The GNDS definition supports data for a PROjectile hitting a TARget for a given Evaluation. In GIDI this is called a PROTARE. For example, a neutron hitting O-16 from the ENDF/B-VIII.0 evaluation. To support a collection of protares, GIDI adds a Map class. The map class reads in a "map" file which specifies a list of projectile/target/evalaution's and their associated protare files. With a map instance, a user can request a specific projectile/target/evaluation and the map instance will return the requested protare.

Beck, Bret↗
NASA NTRS1979

Nuclear gamma-rays from energetic particle interactions

Gamma-ray line emission due to nuclear deexcitation following energetic particle interactions with abundant constituents of cosmic matter is studied. Reactions induced by energetic protons and alpha particles in ambient nuclei (He, C, N, O, Ne, Mg, Al, Si, S, Ca, and Fe) are considered, along with inverse reactions in which energetic nuclei interact with ambient H and He. Line-production cross sections are evaluated by analyzing a large body of laboratory nuclear data. Both prompt gamma rays, produced by direct excitation of nuclear levels and by spallation reactions that leave the secondary nucleus in an excited state, and delayed emission from long-lived radioactive nuclei also produced in the energetic particle reactions are investigated. A line list is provided, and the shapes of the gamma-ray lines are determined. Gamma-ray line production in the interstellar medium is evaluated in detail.

Ramaty, R.↗
NASA NTRS1984

Propagation of heavy cosmic-ray nuclei

Techniques for modeling the propagation of heavy cosmic-ray nuclei, and the required atomic and nuclear data, are assembled in this paper. Emphasis is on understanding nuclear composition in the charge range Z = 3-83. Details of the application of 'matrix methods' above a few hundred MeV/nucleon, a new treatment of electron capture decay, and a new table of cosmic ray-stable isotopes are presented. Computation of nuclear fragmentation cross sections, stopping power, and electron stripping and attachment are briefly reviewed.

Letaw, J. R.↗
DOE OSTI2018

Improved Delayed-Neutron Spectroscopy Using Trapped Ions

The neutrons emitted following the β decay of fission fragments (known as delayed neutrons because they are emitted after fission on a timescale of the β-decay half-lives) play a crucial role in reactor performance and control. Reviews of delayed-neutron properties highlight the need for high-quality data for a wide variety of delayed-neutron emitters to better understand the time dependence and energy spectrum of the neutrons as these properties are essential for a detailed understanding of reactor kinetics needed for reactor safety and to understand the behavior of these reactors under various accident and component-failure scenarios. For fast breeder reactors, criticality calculations require accurate delayed-neutron energy spectra and approximations that are acceptable for light-water reactors such as assuming the delayed-neutron and fission-neutron energy spectra are identical are not acceptable and improved β-delayed neutron data is needed for safety and accident analyses for these reactors. With improved nuclear data, the delayed neutrons flux and energy spectrum could be calculated from the contributions from individual isotopes and therefore could be accurately modeled for any fuel-cycle concept, actinide mix, or irradiation history. High-quality β-delayed neutron measurements are also critical to constrain modern nuclear-structure calculations and empirical models that predict the decay properties for nuclei for which no data exists and improve the accuracy and flexibility of the existing empirical descriptions of delayed neutrons from fission such as the six-group representation

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2019

Generalized Interaction Data Interface and associated packages

GIDIplus contains libraries for reading and using GNDS-formatted nuclear data. It includes sub-packages GIDI, MCGIDI, PoPs, numerical Functions and status Message Reporting along with scripts for building and installing the entire library.

Beck, Bret↗
DOE OSTI2018

BNL NCSP Succession Planning Efforts in FY 2018

This document fulfills a technical support element milestone (TS6:Q4) given in the Five-Year Plan. This document describes BNL succession planning efforts in FY-2018 for the Nuclear Data task area.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

BNL NCSP Succession Planning Efforts in FY 2019

This document fulfills a technical support element milestone (TS6:Q4) given in the Five-Year Plan. This document describes BNL succession planning efforts in FY-2019 for the Nuclear Data task area.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Passive Safety Feature of KIPT Neutron Source Facility

Argonne National Laboratory (ANL) of the United States and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have cooperated on the development, design, and construction of a neutron source facility. The facility was constructed at Kharkov, Ukraine and its commissioning process is underway. The facility has an electron accelerator driven subcritical assembly. The electron beam power is 100 kW using 100 MeV electrons. Tungsten or natural uranium is the target material for generating neutrons driving the subcritical assembly. The subcritical assembly is composed of WWR-M2 Russian fuel assemblies with U-235 enrichment of 19.7 wt%, surrounded by beryllium reflector assembles and graphite blocks. The water coolant operates at room temperature during normal operation, when the facility is operating at full power using 100-KW electron beam power. The passive safety features of the facility are discussed in in this study. Monte Carlo computer code MCNPX was utilized in the analyses with ENDF/B VII.0 nuclear data library.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗