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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 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Plans for Expanded Data Testing at ORNL [Slides]

VALID expansion is on-going and should provide coverage over a wider range of systems in the future. Adding additional application types beyond critical experiments can also be used in expanded data testing. Two other test suites have been developed at ORNL for other purposes, but never waste a good test suite. These suites are more likely to be relevant to testing differences in data as compared to assessing accuracy of evaluations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Spherical nuclei near the stability line and far from it

Results of microscopic and semiphenomenological calculations of features of spherical nuclei lying near the stability line and far from it are presented. The reason why the nuclei being considered are spherical is that they are magic at least in one nucleon sort. The present analysis is performed for Z = 50 and Z = 28 isotopes and for N = 50 isotones, the region extending from neutron-rich to neutron-deficient nuclei being covered. The isotopic dependence of the mean-field spin–orbit nuclear potential is revealed; systematics of energies of levels and probabilities for electromagnetic transitions is examined; and root-mean-square radii of nuclei are calculated, along with the proton- and neutron-density distributions in them. Nuclei in the vicinity of closed shells are considered in detail, and the axial-vector weak coupling constant in nuclei is evaluated. A systematic comparison of the results of calculations with experimental data is performed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Precision Mass Measurements Reveal Low Neutron Pairing in Tin beyond 𝑁=82 and Its Impact on Stellar Nucleosynthesis

We present a study on neutron-rich tin (𝑍 =50) isotopes beyond the doubly closed shell of 𝑁 = 82 through high-precision mass measurements, including the first-ever measurements of the masses of 136 Sn, 137 Sn, and 138 Sn isotopes. These measurements enhance our understanding of the nuclear structure and astrophysical nucleosynthesis in this previously unexplored region. The new mass data are used for evaluation of the final abundances of mass numbers 𝐴 =135 and 137 in 𝑟-process network calculations. Our findings reveal a notable change in the empirical pairing gap for tin isotopes beyond the 𝑁 = 82 closed shell and a shift in the two-neutron-separation energy slope compared to heavier elements above the shell closure. A new set of ab initio calculations effectively describes these observed trends.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

New evaluation on angular distributions and energy spectra for neutron-induced charged-particle measurements

Recent development on neutron-induced charged particle reaction measurements can provide high-quality double differential cross sections at Los Alamos Neutron Science Center. With newly measured cross section data, we found lacking nuclear outputs for neutron-induced charged particle reactions in the latest ENDF/B-VIII.0 library, when compared with Monte Carlo simulations. Here, this paper presents how we improved the missing angular distributions and energy spectra for these reactions and the validation of our new evaluations with the measurements performed with the LENZ instrument at LANSCE. The impact of this additional evaluation is demonstrated by comparing the MCNP simulations with the LENZ experimental data.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2013

Development of an Automated Remedy Performance Evaluation Program - 13622

Performance monitoring is a vital element of groundwater remediation. Unfortunately, the enormous efforts and costs that are expended procuring, managing, processing and storing monitoring data are often not subject to correspondingly rigorous evaluation. This is despite the fact that many steps in the process are predictable and are repeated many times over the remedy life cycle. At the Department of Energy (DOE) Hanford Site, a program is underway to automate many of these steps - processing, formatting any analyzing large volumes of heterogeneous data associated with the operation of several groundwater pump-and-treat (P and T) and in-situ remedies. The Automated Remedy Performance Evaluation Program (ARPEP) was developed from a work-flow process designed to deliver (a) monthly data summaries and preliminary analysis, (b) quarterly performance assessments, and (c) annual roll-up analyses that detect changes in long-term monitoring datasets and support remedy optimization. The intent of the ARPEP is to provide detailed, systematic and traceable data summaries, depictions and analyses that can be used by project scientists to complete their evaluation of remedy performance. The ARPEP work-flow was formalized following extensive review of applicable guidance, regulation and industry standards. The ARPEP incorporates disparate data types collected over different frequencies, such as water levels and pumping rates recorded every minute, and groundwater sample results obtained on quarterly, annual or irregular intervals. The data are processed, reduced to frequencies suitable for assessment, and combined in various ways leading to performance indicators such as (a) pumped well capacities and system downtime that reflect operational performance; (b) hydraulic gradients and areas of hydraulic containment that reflect hydraulic performance; and (c) time-series (longitudinal) and geo-statistical (spatial) trend analyses that reflect progress toward attainment of Remedial Action Objectives (RAOs). The entire sequence of data processing and analysis is undertaken within the R programming environment, an open-source environment for statistical computing and graphics, and is summarized in a comprehensive PDF project report. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Creation of the VADER Code in SCALE [Abstract]

The VADER (Validation Analysis Data Evaluation Resource) is a new module in SCALE 6.3 that has been derived from the legacy USLSTATS program. VADER is a tool that allows the determination of bias and bias uncertainty for criticality safety computational methods. The older USLSTATS program, written in Java, existed outside of SCALE and provided tools to calculate only the confidence band with administrative margin (sometimes called USL-1) and the single-sided uniform width closed interval (USL-2). For normality testing it only offered a crude chi- squared normality test that had no user-configurable options and presented a simple pass/no-pass functionality.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2019

2018 Postclosure Groundwater Monitoring and Inspection Report, Central Nevada Test Area, Nevada, Subsurface Corrective Action Unit 443

This report presents the groundwater monitoring data collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) from the Central Nevada Test Area (CNTA), Nevada, Site, Subsurface Corrective Action Unit (CAU) 443 in Nye County, Nevada (Figure 1). CNTA is the site of an underground nuclear test in 1968 that resulted in residual contamination near the detonation depth of 3200 feet (ft); the contamination requires long-term monitoring. Responsibility for the environmental restoration and long-term monitoring was transferred from DOE’s National Nuclear Security Administration, Nevada Field Office, to LM on October 1, 2006. The environmental restoration and site closure process were completed in 2015 in accordance with the amended Federal Facility Agreement and Consent Order (FFACO) (FFACO 1996, as amended) and all applicable Nevada Division of Environmental Protection (NDEP) policies and regulations. The Closure Report, Central Nevada Test Area, Subsurface Corrective Action, Unit 443 (DOE 2018a), also called the Closure Report, originally was completed in January 2016 and revised in October 2018; it describes LM’s plan for long-term postclosure monitoring. This includes monitoring of the radioisotopes of interest and water elevations, inspecting the site and maintaining the institutional controls (ICs), evaluating and reporting data, and documenting the site’s records and data management processes (DOE 2018a).

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

Data and Insights for the KRUSTY Nuclear-Powered Tests

This document, and the associated files, describe all of the data from the KRUSTY warm criticals and the KRUSTY nuclear system test. The warm criticals were a group of tests where fission power heated the core and the feedback response was studied. There were 3 experiments, the 15-cent run (which was a true “free run”), followed by 30-cent and 60-cent runs, where reactivity was added to heat the core to higher temperatures. The nuclear system test (often referred to as the full-run or the final-run), engaged the power conversion system and evaluated system performance. These experiments are described in a pair of NUCLEAR TECHNOLOGY papers, which includes plots of the data that this document-set includes. Note that a lot of information in this document is based on my interpretation and could be wrong, but I’ve included it to potentially save some people a lot of time and headaches by trying to figure out which instrumentation to believe, but beware treating anything I say as fact. I’ve also included several post-irradiation photos, to show some thermocouple locations and indicate possible changes in emissivity and/or geometry (although no changes in geometry were indicated).

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2021

Generalized Bayesian Framework for Evaluation of Integral Benchmark Experiments

A recently published generalized Bayesian optimization framework has provided a way to retract any or all of the three common assumptions underlying the conventional Generalized Linear Least Squares (GLLS) optimization method based on the concepts introduced in reference two. These assumptions are: 1. Perfection: The model used for data evaluation and the prior probability distribution function (PDF) of generalized* data are perfect; 2. Normality: The prior and posterior PDF are normal; and 3. Linearity: The model is linear. In this work we outline how the framework in 1 could be directly adopted for improved evaluation of nuclear criticality integral benchmark experiments (IBEs) by: 1. Removing the first assumption alone by utilizing the concept of imperfections introduced in 1 to enable evaluation in the presence of discrepancies between the data and model or of missing covariance information by a GLLS method that will be seen as a generalization of the conventional GLLS method employed by the TSURFER code, and by 2. Removing the remaining two assumptions by implement- ing a Markov Chain Monte Carlo method for computation of the posterior PDF in the SAMPLER code, where TSURFER and SAMPLER are the uncertainty quantification (UQ) codes for IBEs in the SCALE code system based on the GLLS, and the stochastic method, respectively.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2013

Airborne Projection of Burning Embers – Planning and Controls for Los Alamos National Laboratory Facilities

As a result of the Las Conchas Fire, the Department of Energy in correspondence SO:32CK 372899 (DOE 2011) requested that LANS take the following action: Evaluate the Las Conchas fire experience and other data on airborne projection of burning embers and the appropriate planning and controls for Los Alamos National Laboratory (LANL) facilities, including nuclear and high hazard facilities. This paper addresses the DOE action by evaluating 1) the meteorology at the time of the accident and implications for new wild land fires; 2) the ability of LANL facilities to withstand fires as a result of burning embers, and 3) LANL programs in place to mitigate the effects of wild land fires. The spread of fire as a result of burning embers is a known and important mechanism. Both empirical and computational studies have been performed, and it is recognized that these studies should continue (Kim 2009, Koo 2010, Sardoy 2007). Due to the locale and environs of LANL, burning brands or embers from forest fires are a credible risk at LANL. With the exception of the Area G TRU Waste Facility, LANL nuclear facilities have fire resistant exteriors with UL Class A roofs. Waste at Area G is stored in fire resistant containers. The laboratory has comprehensive Emergency Operations and Fire Protection Programs, which includes assessing wildland fire risk and mitigating the spread of fires, for example, by maintaining fire breaks and additional defensible buffer areas free of combustibles around LANL facilities and limits on combustible loading. Vegetation is cut-back to at least national consensus standards on a regular basis around nuclear facilities. Fire Department services are provided by Los Alamos County through an agreement with the Department of Energy. The interface between the Fire Department and LANL during emergencies is the Emergency Operations Division. The ability of LANL facilities to withstand a wildland fire was tested by both the Cerro Grande fire in 2000 as well as the Las Conchas fire. No nuclear or high-hazard facilities were damaged even though the Cerro Grande fire burned around a number of the facilities. Since then, the laboratory has strengthened programs to protect against wildland fires.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2023

Generalized Bayesian Framework for Evaluation of Integral Benchmark Experiments

A recently published generalized Bayesian optimization framework has provided a way to retract any or all of the three common assumptions underlying the conventional Generalized Linear Least Squares (GLLS) optimization method based on the concepts introduced in Ref. [2]. These assumptions are: 1. Perfection: The model used for data evaluation and the prior probability distribution function (PDF) of generalized data are perfect. 2. Normality: The prior and posterior PDF are normal. 3. Linearity: The model is linear. In this work we outline how the framework in [1] could be directly adopted for improved evaluation of nuclear criticality integral benchmark experiments (IBEs) by: 1. Removing the first assumption alone by utilizing the concept of imperfections introduced in [1] to enable evaluation in the presence of discrepancies between the data and model or of missing covariance information by a GLLS method that will be seen as a generalization of the conventional GLLS method employed by the TSURFER code, and by 2. Removing the remaining two assumptions by implementing a Markov Chain Monte Carlo method for computation of the posterior PDF in the SAMPLER code, where TSURFER and SAMPLER are the uncertainty quantification (UQ) codes for IBEs in the SCALE code system based on the GLLS and the stochastic method, respectively. The graphic in Figure 1 categorizes the methods discussed in terms of the assumptions that they employ to determine posterior PDFs.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2018

The Effect of the Deformation Parameter on the Cross Sections for Reactions: {sup 110}Pd(d,n){sup 111}Ag and {sup 110}Pd(d, 2n){sup 110m}Ag

In this study, we focused on the effects of the deformation parameter on the cross sections. First, the deformation parameters of target nucleus {sup 110}Pd was determined within the interacting boson model (IBM). Later this parameter was used in the TALYS-1.8 code to calculate the cross sections of the {sup 110}Pd(d,n){sup 111}Ag and {sup 110}Pd(d, 2n){sup 110m}Ag reactions. Moreover, other deformation parameters obtained RIPL-3 and TALYS default were used for the cross section calculation. The calculated results were compared with the experimental nuclear reaction data from EXFOR.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Enhanced Component Performance Study. Emergency Diesel Generators 1998–2013

This report presents an enhanced performance evaluation of emergency diesel generators (EDGs) at U.S. commercial nuclear power plants. This report evaluates component performance over time using Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES) data from 1998 through 2013 and maintenance unavailability (UA) performance data using Mitigating Systems Performance Index (MSPI) Basis Document data from 2002 through 2013. The objective is to present an analysis of factors that could influence the system and component trends in addition to annual performance trends of failure rates and probabilities. The factors analyzed for the EDG component are the differences in failures between all demands and actual unplanned engineered safety feature (ESF) demands, differences among manufacturers, and differences among EDG ratings. Statistical analyses of these differences are performed and results showing whether pooling is acceptable across these factors. In addition, engineering analyses were performed with respect to time period and failure mode. The factors analyzed are: sub-component, failure cause, detection method, recovery, manufacturer, and EDG rating.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2016

Development and Application of Virtual Nuclear Power Plant Platform Concerning Environment and Society Digitally

Virtual Nuclear Power Plant, named Virtual4DS, which is developed by the advanced nuclear energy research team (FDS Team), is a platform for full range, whole cycle safety assessment and emergency decision of nuclear power plant in the digital environment and society. The function framework of Virtual4DS is shown in Fig. 1, and it is designed to ensure an overall optimization design of nuclear power plant, achieve comprehensive evaluation of safety and control of risk, and supply the decision support for accident emergency by the accident probability analysis, environmental consequence assessment and public risk evaluation built on the core of digital reactor and the foundation of the nuclear energy big data. Therefore, Virtual4DS is eligible to be applied in reactor safety, radiation safety and environment impact, emergency and public safety. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2024

Assessment of Measurement Uncertainties in the Jupiter High-240 Experiment

The Jupiter High-240 experiment performed in May of 2019 was previously discussed as a variant of the original Jupiter experiment incorporating plutonium metal alloy fuel plates with higher 240Pu content and lead plates, using both a reference configuration and a second configuration where eight lead plates were replaced with aluminum to simulate voiding. Measurements were recorded for experiment period, the “pressure” of the Comet ram upon closure for each near-critical measurement, and temperature. The experiment reactor period is the time it would take to increase the neutron population by a factor of e. For this experiment, the copper reflectors and upper third of the fuel sits upon a support structure with the lower fuel arrays raised up into the center of the reflectors using a ram (see Fig. 1). The recorded logbook temperature for each measurement corresponds to a resistance temperature detector (RTD) located at the top center of the upper fuel array. This paper summarizes the evaluated uncertainties for the Jupiter High 240 experiment as contributed via the recorded measurements and nuclear data and their assessed impact upon the computation of system reactivity and eigenvalue.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Reactivity measurements using the Zolotukhin-Mogilner Method

The zero count probability method (also called Zolotukhin-Mogilner Method, after its inventors) is a method for measuring the reactivity in nuclear reactors, being a competitor of the [more well-known in the West] Feynman-alpha Method and the Rossi-alpha Method. The modus operandi of this method is using the detector channels where there was no counting at all in order to calculate reactor parameters. In deep subcriticality few models have been tested and this work tries out the Zolotukhin-Mogilner Method in one of such scenarios: measurements will be made in environments below -3,5 k pcm in the zero-potency water-moderated reactor IPEN/MB-01 which is fuelled by UO{sub 2} enriched by 4.3%. These extremely low reactivity environments are required because the chance of no counts on the detector must be significant: otherwise, the method would demand a large time of acquisition of data. Besides that, the method is very simple and straightforward. One of the advantages of this method is that it needs very little data reduction, since the essential data is directly given by the measuring apparatus. The detection will be in charge of modern BF{sub 3} detectors. It will be assumed that, in these deep subcritical systems, the function K{sub eff} = f(N-Nkp) has a linear portion in its first part, resulting of the decomposition of it in a Taylor series. The value of alpha is related to the reactivity ρ with linear dependency. The results will be compared with recent studies of the two main methods described above. Presented for the first time in the 60's, this tool has seen little use in the west hemisphere. This work shows its use in the measurements of the nuclear reactor IPEN/MB-01, as well as the code developed for its employment. It will be the first time this method is used in the south hemisphere. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2016

CASP11 – An Evaluation of a Modular BCL::Fold-Based Protein Structure Prediction Pipeline

In silico prediction of a protein’s tertiary structure remains an unsolved problem. The community-wide Critical Assessment of Protein Structure Prediction (CASP) experiment provides a double-blind study to evaluate improvements in protein structure prediction algorithms. We developed a protein structure prediction pipeline employing a three-stage approach, consisting of low-resolution topology search, high-resolution refinement, and molecular dynamics simulation to predict the tertiary structure of proteins from the primary structure alone or including distance restraints either from predicted residue-residue contacts, nuclear magnetic resonance (NMR) nuclear overhauser effect (NOE) experiments, or mass spectroscopy (MS) cross-linking (XL) data. The protein structure prediction pipeline was evaluated in the CASP11 experiment on twenty regular protein targets as well as thirty-three ‘assisted’ protein targets, which also had distance restraints available. Although the low-resolution topology search module was able to sample models with a global distance test total score (GDT_TS) value greater than 30% for twelve out of twenty proteins, frequently it was not possible to select the most accurate models for refinement, resulting in a general decay of model quality over the course of the prediction pipeline. In this study, we provide a detailed overall analysis, study one target protein in more detail as it travels through the protein structure prediction pipeline, and evaluate the impact of limited experimental data.

59 BASIC BIOLOGICAL SCIENCES↗