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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 739 records · Page 41
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Horizontal Split Table Conceptual Design for Advanced Reactor Validation

Oak Ridge National Laboratory and Lawrence Livermore National Laboratory are collaborating to develop a conceptual design for a horizontal split table for use in performing critical experiments. The goal of this design effort is to provide nuclear data testing and validation capabilities for advanced reactors such as pebble-bed high-temperature gas-cooled reactors, molten salt reactors, and heat pipe microreactor, but it could also be used for the current generation of reactors. The first concept being explored for the horizontal split table, a pebble-bed design based on the HTR-10 reactor, is described in this paper. A critical configuration corresponding to a footprint of about 4.5 m 2 was determined with SCALE/KENO-VI to fit the planned dimensions of the horizontal split table. The similarity of the pebble-bed design and the HTR-10 reactor application was assessed using SCALE/TSUNAMI, and a similarity coefficient $c_k$ of 0.9982 was obtained, proving that the concept will be useful for nuclear data validation and assimilation of pebble-bed type advanced reactors. In the proposed design, the materials with the highest $k_{eff}$ sensitivity are graphite and uranium, demonstrating that particular care must be given to carbon-related cross-section data. The effect of mechanical uncertainties between the fixed and moving tables was also assessed by calculating the reactivity change caused by vertical and horizontal gaps, as well as angular and torsion offsets between the two sides of the horizontal split table concept. The highest relative changes on the concept’s reactivity were caused by angular perturbations. The same analysis process is currently being used to create a molten salt advanced reactor type horizontal split table concept based on the Molten Salt Reactor Experiment (MSRE).

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

DOE Microreactor Program: Summary of Experimental Capabilities Development and Activities

This document provides a summary of the experimental capabilities and activities developed and currently performed under the U.S. Department of Energy’s (DOE’s) Microreactor Program. These capabilities, along with other laboratory capabilities, are available to support developer and other stakeholder needs. Specific experimental capabilities described in this document include the single primary heat extraction and removal emulator (SPHERE), the microreactor agile non-nuclear experimental test bed (MAGNET), microreactor applications research validation and evaluation (MARVEL), yttrium hydride fabrication, the Hypatia critical experiment series, and a brief overview of the National Criticality Experiments Research Center (NCERC), which provides the platform to conduct experiments and training with critical assemblies and fissionable material.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2023

Exploring the process-structure-property relationship of Aerosol Deposition to phosphor coatings for non-contact thermometry

Full-field, multi-measurand diagnostics provide rich validation data necessary to improve the product life cycle time of nuclear safety components. Thermophosphor digital image correlation (TP+DIC) is a method of simultaneously measuring strain and temperature fields using patterned phosphor coatings deposited with aerosol deposition (AD). While TP+DIC produces a functional diagnostic, the coating’s reproducibility and the effect of the patterned features on the inferred temperature remains uncharacterized. This NSR&D project provided the opportunity to study two areas: 1) the tunability and repeatability of aerosol deposition and 2) the robustness of aerosol deposition phosphor on deforming substrates. The first area explores the process-property relationship of parameters elucidating the significance of each on the coating. The second area explores the relationship between the features’ characteristics (namely thickness) and the phosphor emission and inferred temperature. Together, the results will lead to the improved accuracy and functionality of TP+DIC for qualification testing of nuclear safety components.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Precise branching ratio measurement for the superallowed β+ decay of 26 Si: Completion of a second mirror pair

As part of a continuing effort to test the unitarity of the Cabbibo-Kobayashi-Maskawa matrix, we have measured the branching ratio for the superallowed 0 + → 0 + β + -decay transition from 26 Si to be 0.7569(14), a result with 0.18% relative precision. With this result, the ft value for the transition is now established with comparable precision to the well-known superallowed transitions currently used in the determination of V ud . Furthermore, it also completes a second pair of mirror superallowed transitions, 26 Si → 26m Al and 26m Al → 26 Mg, the ratio of whose measured ft values provides a sensitive test of the method used to calculate the isospin-symmetry-breaking correction δ C needed to determine V ud . Like the previously measured ratio for the mass-38 mirror pair, the new result agrees well with the calculation based on Woods-Saxon radial wave functions and strengthens the case for rejecting the calculation that uses Hartree-Fock radial functions.

20 ≤ A ≤ 38↗
DOE OSTI2020

Xenon Abatement Simulations to Support the KAERI Medical Isotope Facility

To maintain and improve the verification regime that is outlined by the Preparatory Commission of the Comprehensive Nuclear Test-Ban Treaty there is a need to understand and reduce the radioxenon releases from medical isotope production facilities. In support of this objective Pacific Northwest National Laboratory (PNNL) was tasked with, modeling and evaluate the abatement process and delay bed designs for the medical isotope production facility under construction by the Korea Atomic Energy Research Institute (KAERI). This report includes this analysis and provides PNNL proposed modifications to the KAERI adsorption bed design.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2025

Preliminary modeling of triply periodic minimal surface (TPMS) structures using RELAP5-3D

With the United States Department of Energy (DOE)’s goal of quadrupling the nation’s nuclear energy supply by 2050, and with the Advanced Fuels Campaign pushing for new types of advanced reactor fuels and geometries, the need has arisen for new nuclear fuel designs. One such design is to swap out current nuclear fuel geometries in exchange for another type of geometry, called a Triply Periodic Minimal Surface (TPMS). TPMSs are self-supporting, infinitely repeating lattices—attributes that lend themselves well to additive manufacturing. These surfaces also possess enhanced heat transfer properties thanks to their internal area changes and large surface-area-to-volume ratios. Their drawback, however, is an increased pressure drop. Given the small amount of correlations and data (Reynolds numbers in the 2,000–8,000 range), and the minimal amount of experience so far obtained by modeling TPMS structures using 1D systems codes such as the Reactor Excursion and Leak Analysis Program (RELAP5-3D), further research into this topic was needed. Using data from the University of Wisconsin - Madison (UW), curve fits were created for both a Heat Transfer Coefficient (HTC) correlation and a Darcy friction factor empirical coefficient correlation. The curves’ coefficients and multipliers were then output and utilized in RELAP5-3D models of two upcoming experiments—Flow Loop for INFLUX Pressure drop (FLIP) and Microreactor Agile Non-nuclear Experimental Test (MAGNET)—aimed at increasing the available data for Reynolds numbers to the 16,000–36,000 range for TPMS structures. The models were run under the conditions utilized by a Computational Fluid Dynamics (CFD) analysis performed by another group at Idaho National Laboratory. Only CFD pressure drop values were obtained from the FLIP test, and those values showed that the RELAP5-3D models had a lower rate of pressure increase in comparison to the CFD values. In addition, there seemed to be a vertical shift upward in the pressure drop for both models whenever the TPMS porosity decreased, and the RELAP5-3D models showed a higher vertical shift in comparison to the CFD values. The MAGNET results did not correspond to any CFD or experimental results against which they could be compared, so they were instead compared against the proposed CFD input conditions. These values were then compared with each other to make sure the model seemed to be performing as expected, paving the way for future tests that can be run for the purpose of further analyses and comparisons. The pressure drop increased with temperature and mass flow rate independently. The temperature change would decrease with increasing mass flow rate and temperature, which was just as we expected based on the fact that the lower viscosity and decreased density would result in higher friction and churning losses. The last metric that was assessed was the enthalpy flow change, which increased with increasing mass flow rate and decreasing temperature.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

Cumulative $\chi^2$ Metric for VALID for ENDF/B-VII.1 and ENDF/B-VIII.0 in SCALE 6.3b9

Nuclear data testing is generally performed in a manner similar to validation: a series of critical benchmark experiments is modeled, and the differences between calculated and expected results are examined to understand the performance of a code and cross section set. This process is repeated for multiple sets of experiments with different transport codes and sometimes with different datasets. Occasionally, data processing differences are also important in understanding the differences in calculated results. Relevant experts then meet periodically to compare results and set priorities for improvement in the next round of data updates. This process has been largely effective, despite the confounding factors of different benchmark sets, application areas, sponsors, nationalities, and the resulting different priorities.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

MEMS RF accelerators for nuclear energy and advanced manufacturing

Energetic ions are widely used to develop radiation hard structural materials and fuels for advanced nuclear energy. Ion beams are also used to generate neutrons for nuclear materials testing, as well as in a series of high impact, high value adding manufacturing processes (ranging from doping of semiconductors to hardening of materials against wear and to increase bio-compatibility of materials). But to date, high power beams of high energy ions are simply too expensive because they are delivered from large single beam accelerators. We have recently demonstrated that MEMS technology enables massively parallel, low cost batch fabrication of ion beams. We propose to scale intense ion accelerators based on MEMS (micro-electro mechanical systems) to high beam power (>10 kW). With our approach, hundreds to thousands of ion beamlets will be densely packed on silicon wafers. Ions are injected and accelerated across gaps formed in stacks of wafers, leading to uniquely high current densities for intense ion accelerators with variable kinetic energy (0.1 to 10 MeV) and variable ion species. Our team brings together experts in high power ion accelerators from Lawrence Berkeley National Laboratory and leading experts in MEMS technology from Cornell University. We will deliver a disruptive technology of low cost, flexible and massively scalable ion accelerators that will enable the rapid development of radiation hard nuclear materials for advanced nuclear energy and enable new applications in manufacturing.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

SERPENT 2 and TRIPOLI-4 neutronics benchmarking of the Jules Horowitz reactor

Jules Horowitz Reactor (JHR) is a future center for nuclear material testing in Europe, currently under construction at CEA Cadarache in southern France. It has been modelled extensively with CEA's HORUS3D/N neutron calculation package, that includes a Monte-Carlo neutron transport code TRIPOLI-4. In order to support the future computational analyses on the reactor core physics, VTT's Monte Carlo neutronics code SERPENT 2 has been used to create an alternative model of the JHR, taking advantage of the pre-existing Constructive Solid Geometry (CSG) structures on which the TRIPOLI-4 model was built. This work describes a benchmark, in which two JHR core configurations were analyzed using both of these models. The first configuration is a fresh fuel core at the beginning of life, in which aluminum based dummy-devices are installed in the reactor test positions. The second configuration represents the end-of-cycle equilibrium core with a heterogeneous burnup distribution, in which CALIPSO devices containing cladding material samples are installed at the in-core experimental positions, while the reflector positions are occupied by DEN-REP devices containing UO{sub 2} fuel. Neutron flux spectra and heat deposition are the parameters of interest in this study, due to their high importance in creating the desired experimental irradiation environment. The impact of delayed gamma energy deposition will be studied in detail, since the two models account for it with different methods. This work aims to establish a SERPENT 2 model of JHR, understanding its differences and agreements with TRIPOLI-4, and discussing its potential future applications. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
NASA NTRS2015

Affordable Development and Demonstration of a Small NTR Engine and Stage: How Small is Big Enough?

In FY11, NASA formulated a plan for Nuclear Thermal Propulsion (NTP) development that included Foundational Technology Development followed by system-level Technology Demonstrations The ongoing NTP project, funded by NASAs Advanced Exploration Systems (AES) program, is focused on Foundational Technology Development and includes 5 key task activities:(1) Fuel element fabrication and non-nuclear validation testing of heritage fuel options;(2) Engine conceptual design;(3) Mission analysis and engine requirements definition;(4) Identification of affordable options for ground testing; and(5) Formulation of an affordable and sustainable NTP development program Performance parameters for Point of Departure designs for a small criticality-limited and full size 25 klbf-class engine were developed during FYs 13-14 using heritage fuel element designs for both RoverNERVA Graphite Composite (GC) and Ceramic Metal (Cermet) fuel forms To focus the fuel development effort and maximize use of its resources, the AES program decided, in FY14, that a leader-follower down selection between GC and cermet fuel was required An Independent Review Panel (IRP) was convened by NASA and tasked with reviewing the available fuel data and making a recommendation to NASA. In February 2015, the IRP recommended and the AES program endorsed GC as the leader fuel In FY14, a preliminary development schedule DDTE plan was produced by GRC, DOE industry for the AES program. Assumptions, considerations and key task activities are presented here Two small (7.5 and 16.5 klbf) engine sizes were considered for ground and flight technology demonstration within a 10-year timeframe; their ability to support future human exploration missions was also examined and a recommendation on a preferred size is provided.

spacecraft design↗
DOE OSTI2023

International Benchmarking: A Global Perspective of Workplace Drug and Alcohol Testing

Workplace drug and alcohol testing has been widely implemented in diverse industries and is designed to detect the use of and deter the influence of legal and illegal substances that would impair the ability to perform work that has significant security and safety implications. Across the globe, patterns of drug and alcohol use and abuse and the regulations controlling drug and alcohol use vary by location (e.g., regions, countries, etc.). The prevalence of workplace drug and alcohol testing and protection of individuals’ rights in the workplace similarly tend to exhibit contextual differences. With the advancements in drug-testing technologies and the recent issuance of guidance for additional testing matrices (e.g., oral fluid, hair, etc.) by the U.S. Department of Health and Human Services, gaining a global perspective on the current state of drug and alcohol testing practices and regulations is important for leveraging such advancements to improve the effectiveness of drug and alcohol testing. The U.S. Nuclear Regulatory Commission (NRC) tasked the Pacific Northwest National Laboratory (PNNL) fitness for duty (FFD) team to conduct a benchmarking analysis of international drug and alcohol testing regulations and programs to identify similarities and differences in workplace testing programs and the basis for any differences. The benchmarking study focuses on a policy analysis and benchmarking metrics comparison among different countries and regions. The policy analysis includes the following three types of relevant international and national policies relevant to drug and alcohol testing in the nuclear industry: 1. National drug and alcohol policy 2. Workplace drug and alcohol testing 3. FFD regulations for Nuclear Power Plants The international drug and alcohol benchmarking metrics focusses on the use of blood, breath, urine, hair, and oral fluid in testing; drug and drug metabolite cutoff values; point-of-collection testing devices; roadside testing methodologies; innovations in drug testing; and the extent of availability of such data. Gaining an understanding of workplace drug and alcohol testing in other countries as well as information about new testing methods, matrices, tools, and technologies that other countries have adopted provides NRC with international comparative information regarding the technical basis for such programs and methods as it relates to the protection of worker and public health and safety.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2026

First full Dalitz plot measurement in neutron 𝛽 decay using the Nab spectrometer and implications for new physics

Precision measurements of observables in neutron 𝛽 decay are used to test the standard model description of the weak interaction and search for evidence of new physics. The Nab experiment at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source was constructed to measure correlations in neutron decay by utilizing an asymmetric spectrometer and novel detection system to accurately reconstruct the proton momentum and electron energy for each 𝛽 decay. This work describes the detection of neutron 𝛽-decay products in the Nab spectrometer and presents the first full Dalitz plot representation of the phase space of neutron 𝛽 decay for all electrons >100 keV. In addition, new constraints are placed on a possible excited neutron state, hypothesized to explain the disagreement between the appearance and disappearance neutron lifetime techniques.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Mechanism by which Tungsten Oxide Promotes the Activity of Supported V 2 O 5 /TiO 2 Catalysts for NO X Abatement: Structural Effects Revealed by 51 V MAS NMR Spectroscopy

Growing concern for environmental pollutants coupled with an expansion of energy demand has promoted significant interest in technologies to abate contaminating species. Nitrogen oxides are particularly alarming due to their numerous detrimental impacts to the environment and public health, where selective catalytic reduction to inert N 2 is an industrially-relevant mitigation technology. Herein, we provide unique, molecular-level insight on the structure and reactivity of V 2 O 5 (-WO 3 )/TiO 2 catalysts employed at stationary facilities for NO x removal. Detailed catalytic testing, spectroscopy (nuclear magnetic resonance, Raman, and electron paramagnetic resonance), and electronic structure-based predictions of 51 V chemical shifts help clarify the promotional role of tungsten oxide and identify an active site requirement for SCR of NO x . We show that progressive addition of vanadia to the catalyst surface increases the catalytic SCR performance and promotes the formation of larger vanadium domains, demonstrating the proportional relationship of SCR reaction rate to [VO x loading]2 for supported V 2 O 5 /TiO 2 catalysts with increasing surface vanadia coverage. Tungsten oxide incorporation enhances catalyst reactivity which is shown to stem not from electronic effects, but from changes to the vanadium structure as observed spectroscopically. The progressive addition of tungsten oxide to the catalyst surface also increases the catalytic performance and promotes the formation of larger vanadium domains, which are beneficial for catalytic turnover in a two-site model. Further, unique monomeric species are confidently ascribed to distorted tetrahedral and square pyramidal structures, resolving a long-standing uncertainty in literature assignments for the signals. These findings provide strong support for both the dual-site requirement for the SCR reaction and the important structural promotional effect that tungsten offers for mitigation of these harmful pollutants.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Waterborn Genotoxicity in Southern Brazil Using Astyanax bifasciatus (Pisces: Teleostei)

Water bodies are often negatively affected by unmediated expansion of surrounding human populations. This makes it essential to establish growth planning strategies that balance productivity and sustainability when creating a viable ecological equilibrium. This study aimed to evaluate genotoxic effects in southern Brazil, using biomarkers in the fish Astyanax bifasciatus, during summer and winter of 2016. The erythrocytic nuclear abnormalities test and the micronucleus test as well as the blood and liver comet assay were used to determine genetic biomarker damage. Four locations and a control point (CP) were sampled in this study. The results demonstrated genotoxicity at all sample locations in the river as compared to the CP in all tests. This is concerning as this water source is the only supply for human populations adjacent and further flows into the greater Iguaçu river basin.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Understanding long-term groundwater flow at Pahute Mesa and vicinity, Nevada National Security Site, USA, from naturally occurring geochemical and isotopic tracers

Abstract Recently collected naturally occurring geochemical and isotopic groundwater tracers were combined with historic data from the Pahute Mesa area of the Nevada National Security Site (NNSS), Nevada, USA, to provide insights into long-term regional groundwater flow patterns, mixing and recharge. Pahute Mesa was the site of 85 nuclear detonations between 1965 and 1992, many of them deeply buried devices that introduced radionuclides directly into groundwater. The dataset examined included major ions and field measurements, stable isotopes of hydrogen (δ 2 H), oxygen (δ 18 O), carbon (δ 13 C) and sulfur (δ 34 S), and radioisotopes of carbon ( 14 C) and chloride ( 36 Cl). Analysis of the patterns of groundwater 14 C data and the δ 2 H and δ 18 O signatures indicates that groundwater recharge is predominantly of Pleistocene age, except for a few localized areas near major ephemeral drainages. Steep gradients in sulfate (SO 4 ) and chloride (Cl) define a region near the western edge of the NNSS where high-concentration groundwater flowing south from north of the NNSS merges with dilute groundwater flowing west from eastern Pahute Mesa in a mixing zone that coincides with a groundwater trough associated with major faults. The 36 Cl/Cl and δ 34 S data suggest that the source of the high Cl and SO 4 in the groundwater was a now-dry, pluvial-age playa lake north of the NNSS. Patterns of groundwater flow indicated by the combined data sets show that groundwater is flowing around the northwest margin of the now extinct Timber Mountain Caldera Complex toward regional discharge areas in Oasis Valley.

58 GEOSCIENCES↗
DOE OSTI2019

Migration of noble gas tracers at the site of an underground nuclear explosion at the Nevada National Security Site

As part of an underground gas migration study, two radioactive noble gases and two stable tracer gases were injected into a nuclear explosion test chimney and allowed to migrate naturally. Soil gas samples were collected from a series of boreholes and a range of depths from the shallow subsurface (3 meters) to deeper levels (~160 meters) over a period of eleven months. These samples have provided insights into the development and evolution of the subsurface plume and constrained the relative migration rates of the radioactive and stable gas species. Analysis of the samples concluded that the stable tracer SF6 was consistently enriched in the subsurface samples relative to the radiotracer 127Xe, but the ratios of SF6 and 37Ar remained similar throughout the samples.

Johnson, Christine M.↗