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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

L-shell spectroscopic diagnostics of radiation from krypton HED plasma sources

X-ray spectroscopy is a useful tool for diagnosing plasma sources due to its non-invasive nature. One such source is the dense plasma focus (DPF). Recent interest has developed to demonstrate its potential application as a soft x-ray source. We present the first spectroscopic studies of krypton high energy density plasmas produced on a 3 kJ DPF device in Singapore. In order to diagnose spectral features, and to obtain a more comprehensive understanding of plasma parameters, a new non-local thermodynamic equilibrium L-shell kinetic model for krypton was developed. It has the capability of incorporating hot electrons, with different electron distribution functions, in order to examine the effects that they have on emission spectra. To further substantiate the validity of this model, it is also benchmarked with data gathered from experiments on the electron beam ion trap (EBIT) at Lawrence Livermore National Laboratory, where data were collected using the high resolution EBIT calorimeter spectrometer.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Development of a krypton-doped gas symmetry capsule platform for x-ray spectroscopy of implosion cores on the NIF

The electron temperature at stagnation of an ICF implosion can be measured from the emission spectrum of high-energy x-rays that pass through the cold material surrounding the hot stagnating core. Here we describe a platform developed on the National Ignition Facility where trace levels of a mid-Z dopant (krypton) are added to the fuel gas of a symcap (symmetry surrogate) implosion to allow for the use of x-ray spectroscopy of the krypton line emission.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Krypton storage capacity of the Earth's lower mantle

Noble gases are important geochemical tracers allowing reconstructing global volatile cycles in Earth's reservoirs. To constrain these fundamental processes, precise data on their partitioning behavior at deep Earth conditions are needed. Such data are only available at moderate pressures up to 25 GPa due to experimental challenges. We have investigated the possibility of noble gas storage in the Earth's lower mantle up to 115 GPa. We studied the incorporation of krypton in the second most abundant lower mantle mineral (Mg 1-x ,Fe x )O (ferropericlase) as well as in liquid metal-alloys by performing experiments up to 115 GPa and 3700 K using the laser-heated diamond anvil cell coupled to post-mortem EMPA analysis and X-ray absorption spectroscopy. The results reveal that, at these extreme conditions, up to 3 wt.% of krypton can be stored in (Mg 1-x ,Fe x )O and 3000 ppm in the Fe-rich liquid metal. For both phases the storage capacities increase with pressure (between 40 GPa and 60 GPa) at a constant high temperature of 2300 K. Fpc has never been considered as a NG host, despite being the second most abundant mineral in the Earth's LM. Using recent accurate compressibility data, we demonstrate that a substitution of krypton into the anion site of (Mg 1-x ,Fe x )O in form of neutral oxygen Schottky defects at diluted lower mantle conditions is possible. This noble gas incorporation mechanism is in agreement with a previous study on bridgmanite. We show that (Mg 1-x ,Fe x )O exhibits higher noble gas storage capacities than bridgmanite through the lower mantle using lattice strain modeling and including experimental solubility and thermoelastic data for neon, argon, krypton and xenon. We also demonstrate that both phases exhibit the highest solubilities for argon and krypton. We used the solubility data from lattice strain modeling to predict noble gas abundances stored in the solid lower mantle after magma ocean crystallization. The modeled abundances show apparent similarities with estimates for the deep noble gas reservoir that are based on either 3He abundances in ocean island basalts or radiogenic 40Ar abundances in the bulk Earth. This strongly indicates that the crystalline lower mantle may play an important role as deep noble gas storage reservoir. We propose, based on considerations on noble gas replenishment from the lower mantle to the atmosphere, that the lower mantle can only contribute to a small fraction of the present-day atmospheric noble gases. This suggests that the lower mantle is an un-degassed reservoir.

58 GEOSCIENCES↗
DOE OSTI2016

Present and future potential of krypton-85 for the detection of clandestine reprocessing plants for treaty verification

Burnup calculations are applied to determine the amount of krypton-85 that is produced during the irradiation of nuclear fuel. Since krypton-85 is most likely released into the atmosphere during reprocessing to separate plutonium, atmospheric transport modeling is used to calculate the worldwide distribution of krypton-85 concentrations stemming from emissions from declared reprocessing plants. Our results are the basis for scenarios in which emissions from clandestine reprocessing facilities have to be detected against various background levels. We conclude that today’s background imposes heavily on the ability to detect small and medium plutonium separation rates; only high separation rates of 1 SQ per week and higher have a chance to be detected with feasible outlay. A fixed network of monitoring stations seems too costly; instead the high number of samples that are required rather calls for mobile sampling procedures, where air samples are collected at random locations over the world and are analyzed in regional laboratories for their krypton-85 concentration. Furthermore, it is argued that krypton-85 emissions from declared reprocessing activities have to be significantly lowered to enable a worldwide verification of the absence of even smaller clandestine reprocessing. For each scenario the number of samples that have to be taken for probable detection is calculated.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

In situ measurement of atmospheric krypton and xenon on Mars with Mars Science Laboratory

Mars Science Laboratory's Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking mission's krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. But, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stable isotopes, unmeasured by Viking. Our new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80 Kr and 82 Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132 Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, but, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites.

58 GEOSCIENCES↗
DOE OSTI2017

The Effect of Krypton Consumption through the Accelerator Channel on Thrust Efficiency of a Morozov’s Stationary Plasma Thruster

Morozov’s stationary plasma thrusters (SPTs) operating on xenon have been successfully used in space technology for many years. At the same time, due to the high cost of xenon, now there is an increased interest in alternative working substances. One of them is krypton. Therefore, research has been conducted earlier on the features of operation and characteristics of SPTs using krypton, which have showed that they are traditional for SPTs. Here, we consider the results of studying the effect of krypton consumption on the thrust efficiency of SPTs. The importance of these results is determined by the fact that they determine the appropriate ranges of SPT regimes when working on krypton.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

A purity monitor for the KEDR liquid krypton calorimeter

We present a purity monitor for the KEDR liquid krypton calorimeter. A new method is suggested based on the usage of a short pulse of a gas discharge as a source of ultraviolet radiation for the photoproduction of electrons in a drift cell of the monitor. This paper describes the design of the monitor, the results of experiments with gaseous and liquid krypton, as well as the experience of using the developed device in the process of krypton purification for the KEDR liquid krypton calorimeter.

Evtushenko, P. N.↗
NASA NTRS2004

High-Power Krypton Hall Thruster Technology Being Developed for Nuclear-Powered Applications

The NASA Glenn Research Center has been performing research and development of moderate specific impulse, xenon-fueled, high-power Hall thrusters for potential solar electric propulsion applications. These applications include Mars missions, reusable tugs for low-Earth-orbit to geosynchronous-Earth-orbit transportation, and missions that require transportation to libration points. This research and development effort resulted in the design and fabrication of the NASA-457M Hall thruster that has been tested at input powers up to 95 kW. During project year 2003, NASA established Project Prometheus to develop technology in the areas of nuclear power and propulsion, which are enabling for deep-space science missions. One of the Project-Prometheus-sponsored Nuclear Propulsion Research tasks is to investigate alternate propellants for high-power Hall thruster electric propulsion. The motivation for alternate propellants includes the disadvantageous cost and availability of xenon propellant for extremely large scale, xenon-fueled propulsion systems and the potential system performance benefits of using alternate propellants. The alternate propellant krypton was investigated because of its low cost relative to xenon. Krypton propellant also has potential performance benefits for deep-space missions because the theoretical specific impulse for a given voltage is 20 percent higher than for xenon because of krypton's lower molecular weight. During project year 2003, the performance of the high-power NASA-457M Hall thruster was measured using krypton as the propellant at power levels ranging from 6.4 to 72.5 kW. The thrust produced ranged from 0.3 to 2.5 N at a discharge specific impulse up to 4500 sec.

Jacobson, David T.↗
NASA NTRS2016

In Situ Measurement of Atmospheric Krypton and Xenon on Mars with Mars Science Laboratory

Mars Science Laboratorys Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking missions krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. However, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stable isotopes, unmeasured by Viking. The new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80Kr and 82Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, however, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites.

Conrad, P. G.↗
DOE OSTI2017

Evolution of the Rayleigh scattering from mixed Ar/Kr clusters during their saturation with krypton atoms

The evolution of the Rayleigh scattering signal from mixed Ar/Kr clusters with variation in the partial Kr concentration in the initial gas mixture is investigated. An addition of krypton in small amounts to argon is found to cause an anomalously rapid increase in the Rayleigh scattering signal amplitude, which is due to a sharp increase in the size of clusters as a result of their saturation with krypton atoms. At a partial krypton concentration above 25% in the initial mixture, the scattering signal amplitude is stabilised because of the condensation saturation during the cluster formation. (nonlinear optical phenomena)

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Helium bubble formation in nickel under in-situ krypton and helium ions dual-beam irradiation

Helium has profound effects on the microstructure and mechanical property of materials used in nuclear power systems. Here to understand the interaction between helium and irradiation-induced defects and its effect on bubble formation, single-beam and dual-beam irradiations on nickel were performed with 16 keV helium ions and 1 MeV krypton ions under in-situ TEM observation. For 1 MeV krypton single-beam irradiation, voids were observed at 600ºC but not at 500ºC and 700ºC. For helium single-beam irradiation at 500ºC, helium moved freely and formed bubble-loop complexes. For dual-beam irradiation at 500ºC, helium was trapped by vacancies and formed bubbles homogeneously. The structure of dislocation loops was also affected by the presence of helium. For krypton single-beam irradiation at 500ºC, the microstructure was {100} periodic wall of faulted and perfect dislocation loops. For dual-beam irradiation at 500ºC, periodic wall was not observed, and dislocation loops were predominantly perfect. For single-beam helium at 500ºC, dislocation loops were produced by athermal process of SIAs ejection or loop punching mechanisms. The interplay between helium and vacancies played an important role on the evolution of helium bubbles and defect microstructures.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Extremely large d 0 magnetism in krypton implanted polar ZnO films

Magnetization is produced in samples of ZnO by implanting krypton ions. Krypton is chemically inert; hence, the magnetization is the consequence of the radiation damage that occurred due to the implantation process. We have found magnetization as large as 185 emu cm –3 at room temperature which corresponds to a moment of ~40 Bohr magnetons per implanted krypton ion. The results are compared for implantation into different ZnO samples, O- and Zn-polar thin films and thin ZnO crystal wafers. The structure of the films has been investigated using RHEED, AFM, XRD and EXAFS. The O-polar film grew in a layer-by-layer mode and after implantation, its lattice spacing increased and the grain size decreased which indicated that the Kr atoms had been incorporated into the lattice. In contrast the Zn-polar film grew in a Stranski–Krastanov mode and its lattice spacing and grain size were almost unchanged by the implantation indicating that the Kr atoms were in the grain boundaries. Raman scattering is used to characterize the radiation damage and to identify scattering from amorphous regions in the grain boundaries and the scattering from point defects. The largest magnetization is found in the O-polar ZnO films where there is a marked grain fragmentation, leading to an increase in the volume of the sample occupied by grain boundaries. As a result, the increase in the number of point defects, which was identified by Raman scattering for films of both polarity, was less effective at producing a magnetic signal than the grain boundaries.

36 MATERIALS SCIENCE↗
NASA NTRS1976

The atmosphere of Mars - Detection of krypton and xenon

Krypton and xenon have been discovered in the Martian atmosphere with the mass spectrometer on the second Viking lander. Krypton is more abundant than xenon. The relative abundances of the krypton isotopes appear normal, but the ratio of xenon-129 to xenon-132 is enhanced on Mars relative to the terrestrial value for this ratio. Some possible implications of these findings are discussed.

Owen, T.↗
NASA NTRS2004

Factors Affecting the Efficiency of Krypton Hall Thrusters

The krypton-fueled Hall thruster offers the possibility of high-specific impulse and long lifetime. NASA's series of Hall thrusters have demonstrated krypton efficiencies only 5 - 15% less than xenon. Larger thrusters have smaller differences in efficiency. Plasma measurements have demonstrated that efficiency is reduced due to a decrease in mass utilization. Current efforts are considering the implications of these results, and how design changes can be made to increase the efficiency of krypton Hall thrusters.

Hofer, Richard R.↗
DOE OSTI2017

Effect of Moisture on the Adsorption of Iodine and Krypton in Multicomponent Streams on the 10 WT% C/ETS-10 Sorbent

Over 13% of the world's energy demand is supplied by nuclear power plants in 31 countries. This demand is growing; by 2030 the IAEA predicts a 100% increase in the demand for nuclear energy. The increase in nuclear energy production imposes a growing strain on the uranium fuel supply. At current consumption rates the world's supply of uranium is projected to last ∼200 years. With the growing energy consumption, uranium supplies will dwindle even more quickly. However, ∼95% of uranium is left in used nuclear fuel (UNF) and may be utilized through reprocessing. A main concern with reprocessing is the release of off-gas. The major constituents of off-gas include {sup 85}Kr, {sup 129}I, {sup 14}C, {sup 3}H, and various Xe isotopes. {sup 85}Kr and {sup 129}I present the largest threat due to their harmful environmental effects and abundance. Several methods have been studied for the removal of these contaminants, including cryogenic distillation, fluorocarbon absorption, wet scrubbing, and adsorption have been employed. Adsorption on porous solid sorbents has the advantages of being simple, effective, and economic. Thus many studies have been performed investigating several sorbents such as silver impregnated mordenite, silver Engelhard titanosilicate 10, chalcogen-based aerogels, and metal organic frameworks. Despite these advances, many of these studies have been conducted under ideal conditions: cryogenic temperature, helium as a carrier gas, and single component adsorption. The need for investigating adsorption under conditions more representative of practical use is needed. Thus our work has been devoted to the study of adsorption of {sup 85}Kr and {sup 129}I from a simulated off-gas on an Engelhard titanosilicate 10 (ETS-10) supported carbon nanopolyhedron sorbent (C/ETS-10) in a multicomponent system at ambient temperatures. Previously we have reported sorption capacities of C/ETS-10 for single component krypton, and iodine. The effects multi-contaminant iodine and krypton and their respective inlet concentrations on the sorption capacity of 10 wt% C/ETS-10 have also been studied. Investigations into the effect of the presence of moisture in the multicomponent gas mixture on the sorption on 10 wt% C/ETS-10 are described in this paper.

36 MATERIALS SCIENCE↗
DOE OSTI1968

Kryptonate Hydrogen Detection System (Final Report)

A prototype model of a multipurpose instrument which demonstrates the applicability of the Kryptonate® technique for detecting hydrogen gas was developed. This report describes the construction of the instrument and presents a laboratory evaluation of its performance. Performance was excellent. The instrument was designed to detect hydrogen in air at concentrations of 0-3% by volume, and to detect hydrogen in nitrogen or other inert gas at concentrations of 0-10% by volume. Other detection levels (both higher and lower) could be set if required. Ultimate response times can be made of the order of 0.5 seconds. The instrument is an all solid state device operating from 120V 60 Hz power source. The instrument has been designed to enable modifications to be made with a minimum amount of difficulty.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗