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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 307 records · Page 17

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NASA NTRS1992

Diploptene: an indicator of terrigenous organic carbon in Washington coastal sediments

The pentacyclic triterpene 17 beta(H),21 beta(H)-hop-22(29)-ene (diploptene) occurs in sediments throughout the Columbia River drainage basin and off the southern coast of Washington state in concentrations comparable to long-chain plantwax n-alkanes. The same relationship is evident for diploptene and long-chain n-alkanes in soils from the Willamette Valley. Microorganisms indigenous to soils and soil erosion are indicated as the biological source and physical process, respectively, for diploptene in coastal sediments. Similarity between the stable carbon isotopic composition (delta 13CPDB) of diploptene isolated from soil in the Willamette Valley (-31.2 +/- 0.3%) and from sediments deposited throughout the Washington coastal environment (-31.2 +/- 0.5%) supports this argument. Values of delta for diploptene in river sediments are variable and 8-17% lighter, indicating that an additional biological source such as methane-oxidizing bacteria makes a significant contribution to the diploptene record in river sediments. Selective biodegradation resulting from a difference in the physicochemical association within eroded particles can explain the absence of the more-13C-depleted form of diploptene in Washington coastal sediments, but this mechanism remains unproven.

Non-NASA Center↗

DOE OSTI2016

A LIBS method for simultaneous monitoring of the impurities and the hydrogenic composition present in the wall of the TJ-II stellarator

The study of plasma-wall interactions and impurity transport in the plasma fusion devices is critical for the development of future fusion reactors. An experiment to perform laser induced breakdown spectroscopy, using minor modifications of our existing laser blow-off impurity injection system, has been set up thus making both experiments compatible. The radiation produced by the laser pulse focused at the TJ-II wall evaporates a surface layer of deposited impurities and the subsequent radiation produced by the laser-produced plasma is collected by two separate lens and fiber combinations into two spectrometers. The first spectrometer, with low spectral resolution, records a spectrum from 200 to 900 nm to give a survey of impurities present in the wall. The second one, with high resolution, is tuned to the wavelengths of the Hα and Dα lines in order to resolve them and quantify the hydrogen isotopic ratio present on the surface of the wall. The alignment, calibration, and spectral analysis method will be described in detail. First experimental results obtained with this setup will be shown and its relevance for the TJ-II experimental program discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2016

Performance testing of a prototype Pd-Ag diffuser

The fusion fuel cycle has gained significant attention over the last decade as interest in fusion programs has increased. One of the critical components of the fusion process is the tritium fuel cycle. The tritium fuel cycle is designed to supply and recycle process tritium at a specific throughput rate. One of the most important processes within the tritium fuel cycle is the clean-up of the of the process tritium. This step will initially separate the hydrogen isotopes (H2, D2, and T2) from the rest of the process gas using Pd-Ag diffusers or permeators. The Pd-Ag diffuser is an integral component for any tritium purification system; whether part of the United States’ defense mission or fusion programs. Domestic manufacturers of Pd-Ag diffusers are extremely limited and only a few manufacturers exist. Johnson-Matthey (JM) Pd-Ag diffusers (permeators) have previously been evaluated for the separation of hydrogen isotopes from non-hydrogen gas species in the process. JM is no longer manufacturing Pd-Ag diffusers and a replacement vendor needs to be identified to support future needs. A prototype Pd-Ag diffuser has been manufactured by Power and Energy, and is considered a potential replacement for the JM diffuser for tritium service. New diffuser designs for a tritium facility for any fusion energy applications must be characterized by evaluating their operating envelope prior to installation in a tritium processing facility. The prototype Pd-Ag diffuser was characterized to determine the overall performance as a function of the permeation of hydrogen through the membrane. The tests described in this report consider the effects of feed gas compositions, feed flow rates, pump configuration and internal tube pressure on the permeation of H2 through the Pd-Ag tubes.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

NASA NTRS2009

NASA Radioisotope Power System Program - Technology and Flight Systems

NASA sometimes conducts robotic science missions to solar system destinations for which the most appropriate power source is derived from thermal-to-electrical energy conversion of nuclear decay of radioactive isotopes. Typically the use of a radioisotope power system (RPS) has been limited to medium and large-scale missions, with 26 U,S, missions having used radioisotope power since 1961. A research portfolio of ten selected technologies selected in 2003 has progressed to a point of maturity, such that one particular technology may he considered for future mission use: the Advanced Stirling Converter. The Advanced Stirling Radioisotope Generator is a new power system in development based on this Stirling cycle dynamic power conversion technology. This system may be made available for smaller, Discovery-class NASA science missions. To assess possible uses of this new capability, NASA solicited and funded nine study teams to investigate unique opportunities for exploration of potential destinations for small Discovery-class missions. The influence of the results of these studies and the ongoing development of the Advanced Stirling Radioisotope Generator system are discussed in the context of an integrated Radioisotope Power System program. Discussion of other and future technology investments and program opportunities are provided.

Sutliff, Thomas J.↗

DOE OSTI2022

Design of the High Rigidity Spectrometer at FRIB

A High Rigidity Spectrometer (HRS) has been designed for experiments at the Facility for Rare-Isotope Beams (FRIB) at Michigan State University (MSU). The HRS will allow experiments to be performed with the most exotic neutron-rich isotopes at high beam energies (≳100 MeV/u). The HRS consists of an analysis beamline called the High-Transmission Beamline (HTBL) and the spectrometer proper called the Spectrometer Section. Here, the maximum magnetic rigidity of the HRS is 8 Tm, which corresponds to the rigidities at which rare-isotope beams are optimally produced at FRIB. The resolving power, angular acceptance, and momentum acceptance are set to match the anticipated scientific program. An ion-optical design developed for the HRS is described in detail, along with the specifications of the associated magnet and detector systems.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

NASA NTRS2002

Chemistry and Transport In a Multi-Dimensional Model

The focus of the work funded under this proposal is the exchange between the stratosphere and the troposphere, and between the troposphere and the blaspheme. These two interfaces represent the frontiers of atmospheric chemistry. It is the combination of exchange processes at both interfaces that ultimately controls how the blaspheme (including human activities) affects the ozone layer. The modeling work was motivated by and attempts to integrate information obtained by aircraft, spacecraft, shuttle and oceanic measurements. The model development and research activities accomplished in the past three years provide a technical and intellectual basis for the research in this group. The innovative part of our research program is related to the IAV of ozone and the hydrological cycle. Other related but independently supported work include the study of isotopic fractionation of atmospheric species, e.g., N2O and CO2. Our theory suggests that we now have the ability to probe the middle atmosphere at a level of sensitivity where subtle details such as the isotopic composition of simple molecules can yield measurable systematic effects. This creates the possibility for probing the chemistry and dynamics of the middle atmosphere using all of the N2O and CO2 isotopologues. In the following we will briefly describe the model development and review the highlights of recent accomplishments.

Yung, Yuk L.↗

NASA NTRS1979

Carbonaceous chondrites. I - Characterization and significance of carbonaceous chondrite /CM/ xenoliths in the Jodzie howardite

Mineralogical, chemical, textural, and isotopic studies of the abundant carbonaceous inclusions in the Jodzie howardite which are consistent with carbonaceous chondrite (CM) characteristics are examined. These CM xenoliths show regolith alteration comparable to the Murray and Murchison meteorites but less than Nogoya, flow-oriented development of phyllosilicates and 'poorly characterized phases', and partial oxidation of sulfides. Temperature-programmed pyrolysis mass spectrometry indicates that gas release patterns of volatiles and hydrocarbons, and N, C, and S contents are typical of CM meteorites. The fact that the Ne content is typical for 'solar' values and the isotopic structure of Xe is 'planetary' indicates that these gases were entrapped by different mechanisms, and cosmic ray exposure ages for the xenoliths agree with the reported exposure age for the eucritic host.

Bunch, T. E.↗

DOE OSTI2019

The Mk-18A Target Recovery Program: A Collaborative Effort - 19186

The National Nuclear Security Administration (NNSA) Office of Nuclear Materials Integration (OMNI) recently developed a strategy and subsequently developed a project scope for recovering valuable, indispensable radioactive isotopes from Mark-18A (Mk-18A) fuel targets currently stored at the Department of Energy's Savannah River Site. The Savannah River National Laboratory, the Oak Ridge National Laboratory, and OMNI in a joint effort with the Department of Energy-Savannah River Office and the Department of Energy-Office of Science developed a comprehensive plan for the Mk-18A fuel target recovery effort. The cooperation between the various organizations and the direction provided by OMNI allowed this effort to remain focused on the desired final deliverable while accomplishing the early goals both on schedule and within the budget constraints provided by OMNI. To date, specific hardware for the recovery effort has been manufactured, various flowsheets outlining the processing of the materials have been developed, and cooperation between the various organizations is remaining streamlined. The recovery and processing of these targets will provide valuable, unique isotopes for use by various organizations both within the DOE and outside of the DOE. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2017

The Los Alamos Neutron Science Center Spallation Neutron Sources

The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ~100 keV. The characteristics of these sources, and ongoing industry program are described in this paper.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2023

Characterization of Aluminum Metal Powders for Plutonium-238 Program

As part of radioisotope thermoelectric generator (RTG) production for power sources in deep space exploration, Oak Ridge National Laboratory (ORNL) produces plutonium-238 ( 238 Pu). To produce 238 Pu, neptunium-237 ( 237 Np) targets are fabricated at ORNL and subsequently irradiated at the High Flux Isotope Reactor (HFIR) at ORNL and the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). Specifically, current flowsheets utilize neptunium dioxide ( 237 NpO 2 ) targets. Aluminum (Al) powder is blended with 237 NpO 2 target material to improve thermal conductivity during irradiation. The current composition of 237 NpO 2 /Al pellets (i.e., cermets, or ceramic–metallics) is 20% 237 NpO 2 , 70% Al, and 10% void space. Al powders utilized by the 238 Pu program are high-fired under vacuum before blending into targets. The primary objective of this work is to measure the physical, chemical, and thermal properties of Al before and after the high-firing process. Properties of interest include the morphology, surface texture, particle size, crystal phase(s), and thermal conductivity of the material. These properties are measured with existing materials characterization equipment at ORNL, including powder x-ray diffraction (pXRD), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), laser flash analysis (LFA), and thermogravimetric analysis (TGA). A secondary objective of this work is to compare the Al powders before and after the high-firing procedure to determine the effects of high-firing on chemical, physical, and thermal properties and to determine the efficacy of the high-firing process.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2018

The ARGUS Solution Reactor and Molybdenum Production: A Summary Report Based on Open Literature

The (Aqueous Homogeneous Reactor) AHR was conceptualized at Los Alamos for work in advancing weapon design with initial experiments completed at Los Alamos National Laboratory (LANL) and Oak Ridge National Laboratory (ORNL) in the early 1940s and 1950s. The reactor design was discovered to be an efficient mean of production for medical radio isotopes (e.g. molybdenum-99 and other fission products) due to its streamlined process of extracting target radioactive sources from the fissile solution via a separation system. As the demand for medical radioisotopes has increased so has the need for a safe and low cost isotope source, the most commonly used of which is technetium-99m (99m Tc), daughter product from molybdenum decay. Studies indicate solution reactors pose a significantly lower hazard to the workers, public and environment, compared to other modern reactors (International Atomic Energy Agency 2008). The inherent safety and ability to selectively extract radionuclides from its fuel solution make AHRs particularly well suited for medical isotope production. This discussion narrows its focus to one of the longest running aqueous homogeneous reactor systems, ARGUS. A study of the conversion of ARGUS to a low-enriched uranyl (LEU) sulfate fuel solution was part of the Global Threat Reduction Initiative (GTRI) program. The goal of this paper is to provide a summary of the ARGUS reactor system based on open literature available.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2017

Special Actinide Recovery from Mark-18A Target Material

The US Department of Energy (DOE) manages an inventory of materials that contains a range of long-lived radioactive isotopes that were produced from the 1960s through the 1980s by irradiating targets in production reactors at the Savannah River Site (SRS) to produce special heavy isotopes for DOE programmatic use, scientific research, and industrial and medical applications. During the late 1960s, one of the production reactors was configured to operate in a very high flux mode, and >8 kg of 242Pu plutonium contained in Mark-18A (Mk-18A) targets was irradiated to produce 252Cf for use in neutron source applications. Twenty-one targets were processed at the Oak Ridge National Laboratory (ORNL) to recover the 252Cf, heavy curium (i.e., curium rich in 246Cm through 248Cm), and 244Pu. Sixty-five of the Mark-18A targets were not processed and are currently in wet storage at SRS. DOE’s Office of Nuclear Materials Integration (ONMI) established a Mk-18A Target Material Recovery Program (MTMRP) to separate and preserve the unique materials in these targets. Evaluations are also under way to determine whether additional rare long-half-life fission product isotopes present in the targets in much smaller quantities, such as 93Zr, can be economically recovered. These evaluations include assessment of the quality, value, and demand of the materials; process modifications required to facilitate recovery; and the incremental costs for their recovery from the Mk-18A targets.

Patton, Bradley↗

DOE OSTI2016

Diphosphine-Protected Au 22 Nanoclusters on Oxide Supports Are Active for Gas-Phase Catalysis without Ligand Removal

Investigation of monodispersed and atomically-precise Au nanoclusters provides a route to understand the roles of coordination, size, and ligand effects in Au catalysis. We have explored the catalytic behavior of a newly-synthesized Au 22 (L 8 ) 6 nanocluster (L = 1,8-bis(diphenylphosphino) octane) with in situ uncoordinated Au sites supported on TiO 2 , CeO 2 and Al 2 O 3 . Stability of the supported Au 22 nanoclusters was probed structurally by EXAFS and HAADF-STEM, and their adsorption and reactivity for CO oxidation were investigated by IR absorption spectroscopy and temperature programed flow reaction. Low temperature CO oxidation activity was observed for the supported pristine Au 22 (L 8 ) 6 nanoclusters without ligand removal. Isotopically labeled O 2 was used to demonstrate that the reaction pathway occurs through a redox mechanism, consistent with the observed support-dependent activity trend: CeO 2 > TiO 2 > Al 2 O 3 . Substantiated by density functional theory (DFT) calculations, we conclude that the uncoordinated Au sites in the intact Au 22 (L 8 ) 6 nanoclusters are capable of adsorbing CO, activating O2 and promoting CO oxidation reaction. Thanks to the presence of the in situ coordination unsaturated Au atoms, this work is the first clear demonstration of a ligand-protected Au nanocluster that are active for gas phase catalysis without the need of ligand removal.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS1978

Detection of hydrogen chloride gas in air

Launch vehicle effluent (LVE) monitoring is part of NASA's overall tropospheric and stratospheric environmental program. Following nine techniques are evaluated and developed in report: bubbler method, pH measurements, indicator tubes, microcoulometers, modified condensation nuclei counter, dual-isotope absorption, gas-filter correlation, chemiluminescent nitric oxide detection, chemiluminescent luminol-oxidation detection.

Gregory, G. L.↗

DOE OSTI2019

Final Report for the Workshop for Applied Nuclear Data Activities

The Workshop for Applied Nuclear Data Activities (WANDA) was held at the Elliot School of International Affairs at George Washington University from 22 to 25 January 2019. The purpose of WANDA was to bring subject matter experts from the national laboratories, universities and industry together with government program managers and their advisors to develop collaborative plans of action (e.g., roadmaps ) to address outstanding issues in nuclear data that effect applications ranging from nuclear energy to national security and nonproliferation to isotope production. WANDA was the latest in a series of collaborative, cross-programmatic workshops focused on nuclear data needs for applications that started in 2015 with the Nuclear Data Needs and Capabilities for Applications Workshop (NDNCA) and continuing with the Nuclear Data Roadmapping Enhancement Workshop (NDREW) in 2018 focused on nuclear data needs for applications. NDREW and WANDA played an important role in providing guidance for the recently created Nuclear Data Interagency Working Group (NDIAWG) comprised of program managers from a panoply government agencies. The NDIAWG issued two Funding Opportunity Announcements (FOA) in FY2017 and FY2018 which are supporting collaborative efforts to address high-priority nuclear data needs.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

NASA NTRS2011

Nutrition Research: Basis for Station Requirements

Prior to the Shuttle program, all understanding of nutritional needs in space came from Skylab metabolic research. Because Shuttle flights were short, most less than 14 days, research focused on major nutritional issues: energy (calories), protein and amino acids, water and electrotypes, with some more general physiology studies that related to iron and calcium. Using stable isotope tracer studies and diet intake records, we found that astronauts typically did not consume adequate calories to meet energy expenditure. To monitor energy and nutrient intake status and provide feedback to the flight surgeon and the astronauts, the International Space Station (ISS) program implemented a weekly food frequency questionnaire and routine body mass measurements. Other Shuttle investigations found that protein turnover was higher during flight, suggesting there was increased protein degradation and probably concurrent increase in protein synthesis, and this occurred even in cases of adequate protein and caloric intake. These results may partially explain some of the loss of leg muscle mass. Fluid and electrolyte flight studies demonstrated that water intake, like energy intake, was lower than required. However, sodium intakes were elevated during flight and likely related to other concerns such as calcium turnover and other health-related issues. NASA is making efforts to have tasty foods with much lower salt levels to reduce sodium intake and to promote fluid intake on orbit. Red blood cell studies conducted on the Shuttle found decreased erythrogenesis and increased serum ferritin levels. Given that the diet is high in iron there may be iron storage health concerns, especially related to the role of iron in oxidative damage, complicated by the stress and radiation. The Shuttle nutrition research lead to new monitoring and research on ISS. These data will be valuable for future NASA and commercial crewed missions.

Lane, Helen W.↗

DOE OSTI2018

Monthly Atmospheric 13C/12C Isotopic Ratios for 11 SIO Stations (1977-2008)

Stable isotopic measurements for atmospheric 13C/12C and 18O/16O at global sampling sites were initiated by Dr. C.D. Keeling and co-workers at Scripps Institution of Oceanography (SIO) in 1977. These isotopic measurements complement the continuing global atmospheric and oceanic CO2 measurements initiated by Keeling in 1957. This work is currently being continued under the direction of R.F. Keeling, who also runs a parallel program at SIO to measure changes in atmospheric O2 and Ar abundances (Scripps O2 Program). A more complete set of 13CO2 data is found online at http://scrippsco2.ucsd.edu/data/atmospheric_co2.htmlFor access to the data files, click this link to the CDIAC data transition website: http://cdiac.ess-dive.lbl.gov/trends/co2/iso-sio/iso-sio.html

12C↗

DOE OSTI2020

Los Alamos National Laboratory Release of Cesium-137 Corrective Action Plan

This Corrective Action Plan (CAP) was developed by a team chartered by John Sarrao, Deputy Director for Science, Technology, and Engineering (DDSTE), to review and respond to the findings of the Joint National Nuclear Security Administration/Triad National Security (NNSA/Triad) Investigation Team (JIT) Joint Investigation Report for the “Sealed Source Recovery at the University of Washington Harborview Training and Research Facility Results in Release of Cesium-137 on May 2, 2019,” dated March 30, 2020. On May 2, 2019, International Isotopes, Inc. (INIS), a subcontractor to Triad National Security, LLC, inadvertently breached a sealed cesium-137 source at the University of Washington (UW), Harborview Medical Center Research and Training (HRT) building in downtown Seattle while attempting to recover the source for the National Nuclear Security Administration (NNSA) Off-Site Source Recovery Program (OSRP). The source breach resulted in contamination of personnel and the HRT building, as well as a release of radioactive material to the environment

07 ISOTOPE AND RADIATION SOURCES↗