Science.gov

Sample records for nuclear superheating

  1. BOILER-SUPERHEATED REACTOR

    DOEpatents

    Heckman, T.P.

    1961-05-01

    A nuclear power reactor of the type in which a liquid moderator-coolant is transformed by nuclear heating into a vapor that may be used to drive a turbo- generator is described. The core of this reactor comprises a plurality of freely suspended tubular fuel elements, called fuel element trains, within which nonboiling pressurized liquid moderator-coolant is preheated and sprayed through orifices in the walls of the trains against the outer walls thereof to be converted into vapor. Passage of the vapor ovcr other unwetted portions of the outside of the fuel elements causes the steam to be superheated. The moderatorcoolant within the fuel elements remains in the liqUid state, and that between the fuel elements remains substantiaily in the vapor state. A unique liquid neutron-absorber control system is used. Advantages expected from the reactor design include reduced fuel element failure, increased stability of operation, direct response to power demand, and circulation of a minimum amount of liquid moderatorcoolant. (A.G.W.)

  2. Apfel's superheated drop detector

    NASA Astrophysics Data System (ADS)

    D'Errico, Francesco

    2001-05-01

    The introduction of new approaches for radiation dosimetry is rare. A similar breakthrough occurred in 1979, when Robert Apfel invented the superheated drop detector, a miniature relative of the bubble chamber. A fundamental in high-energy particle physics, the bubble chamber utilizes a liquid briefly brought to a transient, radiation-sensitive superheated state by reducing its pressure. Mass boiling of the liquid is prevented by cyclic pressurization, drastically limiting the detection efficiency. In Apfel's detector, the liquid is kept in a steady superheated state by fractionating it into droplets and dispersing them in an immiscible host fluid, a perfectly smooth and clean container. The approach extends the lifetime of the metastable droplets to the point that practical application in radiation dosimetry is possible. Bubble formation is measured from the volume of vapor or by detecting individual vaporizations acoustically. Various halocarbons are employed and this permits a wide range of applications. Moderately superheated halocarbons are used for neutron measurements, since they are only nucleated by energetic neutron recoil particles. Highly superheated halocarbons nucleate with much smaller energy deposition and are used to detect photons and electrons. This paper reviews the radiation physics of superheated emulsions and their manifold applications.

  3. Differences between solid superheating and liquid supercooling.

    PubMed

    Bai, Xian-Ming; Li, Mo

    2005-10-15

    The thermodynamic and kinetic behaviors for solid superheating and liquid supercooling were critically examined and compared via molecular-dynamics simulations. It is shown that the large elastic energy associated with internal melting and solid-liquid interface disorder play important roles in superheating. The growth rate is anisotropic for supercooling, but isotropic for superheating. Supercooling can be well described by the classical nucleation theory, whereas superheating shows many exceptions. The underlying mechanisms for these differences are discussed.

  4. Zirconium alloys with small amounts of iron and copper or nickel show improved corrosion resistance in superheated steam

    NASA Technical Reports Server (NTRS)

    Greenberg, S.; Youngdahl, C. A.

    1967-01-01

    Heat treating various compositions of zirconium alloys improve their corrosion resistance to superheated steam at temperatures higher than 500 degrees C. This increases their potential as fuel cladding for superheated-steam nuclear-fueled reactors as well as in autoclaves operating at modest pressures.

  5. Regenerative superheated steam turbine cycles

    NASA Technical Reports Server (NTRS)

    Fuller, L. C.; Stovall, T. K.

    1980-01-01

    PRESTO computer program was developed to analyze performance of wide range of steam turbine cycles with special attention given to regenerative superheated steam turbine cycles. It can be used to model standard turbine cycles, including such features as process steam extraction, induction and feedwater heating by external sources, peaking, and high back pressure. Expansion line efficiencies, exhaust loss, leakages, mechanical losses, and generator losses are used to calculate cycle heat rate and generator output. Program provides power engineer with flexible aid for design and analysis of steam turbine systems.

  6. Evaporation waves in superheated dodecane

    NASA Astrophysics Data System (ADS)

    Simões-Moreira, J. R.; Shepherd, J. E.

    1999-03-01

    We have observed propagating adiabatic evaporation waves in superheated liquid dodecane, C12H26. Experiments were performed with a rapid decompression apparatus at initial temperatures of 180 300°C. Saturated dodecane in a tube was suddenly depressurized by rupturing a diaphragm. Motion pictures and still photographic images, and pressure and temperature data were obtained during the evaporation event that followed depressurization. Usually, a front or wave of evaporation started at the liquid free surface and propagated into the undisturbed regions of the metastable liquid. The evaporation wave front moved with a steady mean velocity but the front itself was unstable and fluctuating in character. At low superheats, no waves were observed until a threshold superheat was exceeded. At moderate superheats, subsonic downstream states were observed. At higher superheats, the downstream flow was choked, corresponding to a Chapman Jouguet condition. At the most extreme superheat tested, a vapour content of over 90% was estimated from the measured data, indicating a nearly complete evaporation wave. Our results are interpreted by modelling the evaporation wave as a discontinuity, or jump, between a superheated liquid state and a two-phase liquid vapour downstream state. Reasonable agreement is found between the model and observations; however, there is a fundamental indeterminacy that prevents the prediction of the observed wave speeds.

  7. SUPERHEATING IN A BOILING WATER REACTOR

    DOEpatents

    Treshow, M.

    1960-05-31

    A boiling-water reactor is described in which the steam developed in the reactor is superheated in the reactor. This is accomplished by providing means for separating the steam from the water and passing the steam over a surface of the fissionable material which is not in contact with the water. Specifically water is boiled on the outside of tubular fuel elements and the steam is superheated on the inside of the fuel elements.

  8. Ultrafast Nanocalorimetry and Superheating in Linear Polymers

    NASA Astrophysics Data System (ADS)

    Schick, Christoph; Minakov, Alexander; Wurm, Andreas

    2009-03-01

    To study phase transition kinetics on submillisecond time scale a set of new membrane gauges for ultrafast scanning nanocalorimetry were constructed. Controlled ultrafast cooling, as well as heating, up to 10E6 K/s was attained. The characteristic rate R0 corresponding to the quasi-static limit of the temperature change in the membrane-gas system was determined. The rate R0 equals 10E5 K/s for the different gauges in helium gas. The method was applied for the measurements of the superheating phenomenon in a set of linear polymers iPS, PBT, PET, iPP. A power law relation between the superheating and the heating rate was observed in the broad range 10E-2 -- 10E4 K/s of the heating rates. A limiting superheating of about 10% of the melting temperature was observed at rates above 10E4 -- 10E5 K/s. This limit depends on the annealing conditions before the sample melting. The observed superheating limit, as well as the power law, can be accounted for the internal stresses induced by the superheating near the crystalline-amorphous interface in semicrystalline polymers, which are related to the thermal expansion gradients inherent for a semicrystalline material.

  9. A sensitive neutron dosimeter using superheated liquid.

    PubMed

    Das, M; Roy, B; Chatterjee, B K; Roy, S C

    2000-01-01

    The present work relates to a sensitive neutron dosimeter, a device for monitoring neutron dose in some accelerator and reactor sites. This device is capable of measuring a neutron dose as small as 0.1 microSv using superheated liquid as a sensitive liquid. The nucleation was measured by the volumetric method developed in our laboratory. The dose response of superheated drops of four liquids having boiling points of 8.92, -29.79, -40.75 and -45.6 degrees C, irradiated by a 3 Ci Am-Be neutron source has also been presented in this article.

  10. Melting mechanisms at the limit of superheating.

    PubMed

    Jin, Z H; Gumbsch, P; Lu, K; Ma, E

    2001-07-30

    The atomic-scale details during melting of a surface-free Lennard-Jones crystal were monitored using molecular dynamics simulations. Melting occurs when the superheated crystal spontaneously generates a sufficiently large number of spatially correlated destabilized particles that simultaneously satisfy the Lindemann and Born instability criteria. The accumulation and coalescence of these internal local lattice instabilities constitute the primary mechanism for homogeneous melt nucleation inside the crystal, in lieu of surface nucleation for equilibrium melting. The vibrational and elastic lattice instability criteria as well as the homogeneous nucleation theory all coincide in determining the superheating limit.

  11. Bubble growth in superheated He-II

    SciTech Connect

    Dresner, L.

    1988-01-01

    Bubble growth in superheated He-II is controlled by the transfer of heat to the surface of the growing bubble by nonlinear Gorter-Mellink counterflow. The present work presents analytic formulas for the bubble radius as a function of time in the limiting cases of small and large superheats. The formulas include the effect of the inertial reaction of the surrounding liquid to the expansion of the bubble. A numerical example shows that bubble velocities of the order of meters per second are possible. A related problem, involving only heat transfer but no movement of the liquid, is the motion of the free surface of superheated He-II in a very long tube. This problem has a similarity solution. The interfacial velocity in the tube is much smaller than the bubble growth velocity. 1 ref.

  12. Comparative Study of Materials' Behaviour in Supercritical Water and Superheated Steam

    NASA Astrophysics Data System (ADS)

    McClure, Peter

    Advanced supercritical water cooled nuclear reactors require materials to survive a corrosive, high temperature fluid environment, in addition to radiation effects. This thesis details corrosion testing of A286 (iron-nickel based), AISI 310 stainless steel, and IN625 (nickel based) in supercritical water (29 MPa) and superheated steam (ambient pressure) at 650°C to understand effects of materials' composition and fluid pressure. A superheated steam testing rig was designed and an autoclave was assembled. Samples were tested for 100, 200, and 300 hours, then analysed for weight gain and surface appearance; surface morphology and composition were determined through scanning electron microscope imaging and energy-dispersive X-ray spectroscopy. A286 demonstrated poor corrosion resistance due to low chromium content. AISI 310 and IN625 demonstrated similarly strong corrosion resistance in supercritical water through formation of adherent scales, but poor corrosion resistance in superheated steam due to scale spallation. Supercritical water and superheated steam corrosion behaviour were non-analogous.

  13. High-energy neutron detection and spectrometry with superheated emulsions

    NASA Astrophysics Data System (ADS)

    d'Errico, Francesco; Prokofiev, Alexander; Sannikov, Alexander; Schuhmacher, Helmut

    2003-06-01

    The response of some superheated emulsions was investigated using quasi-monoenergetic neutron beams in the 46-134 MeV energy range at the Université Catholique de Louvain, Louvain la Neuve, Belgium and at The Svedberg Laboratory, Uppsala, Sweden. In order to determine the detector response to the high-energy beams, the spectra of incident neutrons were folded over functions modeled after the cross-sections for the neutron-induced production of heavy ions from the detector elements. The cross-sections for fluorine and chlorine were produced in this work by means of the Monte Carlo high-energy transport code HADRON based on the cascade-exciton model of nuclear interactions.

  14. Induction of hypocrellin production by Triton X-100 under submerged fermentation with Shiraia sp. SUPER-H168.

    PubMed

    Cai, Yujie; Liao, Xiangru; Liang, Xiaohui; Ding, Yanrui; Sun, Jun; Zhang, Dabing

    2011-10-01

    Hypocrellins are important photodynamic therapy compounds for cancer disease. The effect of surfactants on hypocrellin production of Shiraia sp. SUPER-H168 was evaluated under submerged fermentation condition. The production of hypocrellins could reach 780.6 mg/l with the addition of Triton X-100, confirmed by color reaction, high performance liquid chromatography, electrospray ionization mass spectrometry and nuclear magnetic resonance experiments. According to our observation, treatment of the culture at the beginning of the fermentation was most effective, and the yield of hypocrellins was much lower with the addition of Triton X-100 during the log phase and stationary phase. Shiraia sp. SUPER-H168 could not produce hypocrellin with the addition of other tested surfactants, such as Tween 40, Triton X-114 and SDS. The experimental results indicated that Shiraia sp. SUPER-H168 could not produce hypocrellins without Triton X-100 under submerged fermentation condition.

  15. Method and apparatus for de-superheating refrigerant

    DOEpatents

    Zess, J.A.; Drost, M.K.; Call, C.J.

    1997-11-25

    The present invention is an apparatus and method for de-superheating a primary refrigerant leaving a compressor wherein a secondary refrigerant is used between the primary refrigerant to be de-superheated. Reject heat is advantageously used for heat reclaim. 7 figs.

  16. Dark matter searches using superheated liquids

    NASA Astrophysics Data System (ADS)

    Manuel, Bou-Cabo; Miguel, Ardid; Ivan, Felis

    2016-07-01

    Direct detection of dark matter is one of the most important topics in modern physics. It is estimated that 22% of universe matter is composed by dark matter in front of 0.4% of ordinary matter like stars, galaxies planets and all kind of known astrophysical objects. Several kinds of experiments are nowadays involved in detection of one of the more accepted particle candidates to be dark matter: WIMPs (Weakly Interacting Massive Particles). These detectors, using several kinds of techniques: Cryogenic semiconductors, scintillation materials like I Na or noble gas chambers among others, are reporting very interesting but inconclusive results. In this paper a review of detectors that are using the superheated liquid technique in bubble chambers in order to detect WIMPs is reported. Basically, we will report about Coupp (Chicagoland observatory for underground particle physics), PICO that is composed by Coupp and Picasso researchers having the aim to build a ton experiment and also about a new detector named MOSCAB (Materia oscura a bolle) that recently published a first results of a test chamber that uses also superheated liquid technique but as a Geyser chamber.

  17. Impact of droplet on superheated surfaces

    NASA Astrophysics Data System (ADS)

    Lohse, Detlef; Staat, Hendrik J. J.; Tran, Tuan; Prosperetti, Andrea; Sun, Chao

    2012-11-01

    At impact of a liquid droplet on a smooth surface heated way above the liquid's boiling point, the droplet spreads without any surface contact, floating on its own (Leidenfrost-type) vapor layer, and then bounces back. We show that the dimensionless maximum spreading factor Γ, defined by the ratio of the maximal spreading diameter and the droplet diameter, shows a universal scaling Γ ~ Weγ with the Weber number We - regardless of surface temperature and of liquid properties - which is much steeper than that for the impact on non-heated (hydrophilic or hydrophobic) surfaces, for which γ = 1 / 4 . Based on the idea that the vapor shooting out of the gap between the droplet and the superheated surface drags the liquid outwards, we derive scaling laws for the spreading factor Γ, the vapor layer thickness, and the vapor flow velocity.

  18. Viscous fingers in superheated geothermal systems

    SciTech Connect

    Fitzgerald, Shaun D.; Woods, Andres W.; Shook, Mike

    1994-01-20

    In this paper we investigate the physical controls upon the rate of vaporization of liquid as it is injected into a porous layer containing superheated vapour. We develop a simple model of the process and show that if liquid is injected at a relatively high rate, a small fraction of the liquid vaporizes and the porous layer becomes filled with hot liquid. In contrast, at low rates of injection a large fraction of the liquid may vaporize. We also describe a new and fundamental instability that can develop at a migrating liquid-vapour interface if the rate of injection is sufficiently small. This phenomenon is manifest in the form of liquid fingers growing from a liquid-vapour interface and is investigated through the use of analytical, experimental and numerical techniques.

  19. CFD Modeling of Superheated Fuel Sprays

    NASA Technical Reports Server (NTRS)

    Raju, M. S.

    2008-01-01

    An understanding of fuel atomization and vaporization behavior at superheat conditions is identified to be a topic of importance in the design of modern supersonic engines. As a part of the NASA aeronautics initiative, we have undertaken an assessment study to establish baseline accuracy of existing CFD models used in the evaluation of a ashing jet. In a first attempt towards attaining this goal, we have incorporated an existing superheat vaporization model into our spray solution procedure but made some improvements to combine the existing models valid at superheated conditions with the models valid at stable (non-superheat) evaporating conditions. Also, the paper reports some validation results based on the experimental data obtained from the literature for a superheated spray generated by the sudden release of pressurized R134A from a cylindrical nozzle. The predicted profiles for both gas and droplet velocities show a reasonable agreement with the measured data and exhibit a self-similar pattern similar to the correlation reported in the literature. Because of the uncertainty involved in the specification of the initial conditions, we have investigated the effect of initial droplet size distribution on the validation results. The predicted results were found to be sensitive to the initial conditions used for the droplet size specification. However, it was shown that decent droplet size comparisons could be achieved with properly selected initial conditions, For the case considered, it is reasonable to assume that the present vaporization models are capable of providing a reasonable qualitative description for the two-phase jet characteristics generated by a ashing jet. However, there remains some uncertainty with regard to the specification of certain initial spray conditions and there is a need for experimental data on separate gas and liquid temperatures in order to validate the vaporization models based on the Adachi correlation for a liquid involving R134A.

  20. High-energy neutron dosimetry with superheated drop detectors.

    PubMed

    d'Errico, F; Agosteo, S; Sannikov, A V; Silari, M

    2002-01-01

    A systematic analysis of the response of dichlorodifluoromethane superheated drop detectors was performed in the 46-133 MeV energy range. Experiments with quasi-monoenergetic neutron beams were performed at the Université Catholique de Leuvain-la-Neuve, Belgium and the Svedberg Laboratory, Sweden, while tests in a broad field were performed at CERN. To determine the response of the detectors to the high-energy beams, the spectra of incident neutrons were folded over functions modelled after the cross sections for the production of heavy ions from the detector elements. The cross sections for fluorine and chlorine were produced in this work by means of the Monte Carlo high-energy transport code HADRON based on the cascade exciton model of nuclear interactions. The new response data permit the interpretation of measurements at high-energy accelerators and on high-altitude commercial flights, where a 30-50% under-response had been consistently recorded with respect to neutron dose equivalent. The introduction of a 1 cm lead shell around the detectors effectively compensates most of the response defect. PMID:12382936

  1. Heat treatment of scallop adductor muscle using superheated steam.

    PubMed

    Abe, T; Miyashita, K

    2007-08-01

    Scallop (Patinopecten yessoensis) adductor muscles were heated using superheated steam (150 and 200 degrees C), boiling (98 degrees C), and normal steaming (95 degrees C). The amounts of amino acids, water-soluble peptides, and nucleotides, expressed as extractive nitrogen in scallop products, are very important elements of quality and taste. After 15-min heating of scallop muscles with normal steaming and boiling, respective losses of 50% and 64% of the extractive nitrogen were observed. However, most extractive nitrogen (> 86%) remained in the scallop muscles treated with superheated steam at 150 and 200 degrees C. Protective effects of superheated steam against elution loss of nitrogen compounds were also observed in amino acid analyses of the heated products. The scallop-muscle surface temperature during treatment with superheated steam increased more quickly than that with normal steaming and boiling. The rapid water loss and the surface protein denaturation engendered formation of a 30-mum-thick film covering the surface, which prevented extractive nitrogen loss from internal tissues. Superheated steam treatment at 200 degrees C caused browning, surface shrinkage, and 47% weight loss. In marked contrast, the appearance and the weight loss of sample treated at 150 degrees C were almost the same as those of normal steaming and boiling-treated samples. These results suggested that superheated steaming at 150 degrees C is an optimal heat treatment of scallop adductor muscles.

  2. Heat treatment of scallop adductor muscle using superheated steam.

    PubMed

    Abe, T; Miyashita, K

    2007-08-01

    Scallop (Patinopecten yessoensis) adductor muscles were heated using superheated steam (150 and 200 degrees C), boiling (98 degrees C), and normal steaming (95 degrees C). The amounts of amino acids, water-soluble peptides, and nucleotides, expressed as extractive nitrogen in scallop products, are very important elements of quality and taste. After 15-min heating of scallop muscles with normal steaming and boiling, respective losses of 50% and 64% of the extractive nitrogen were observed. However, most extractive nitrogen (> 86%) remained in the scallop muscles treated with superheated steam at 150 and 200 degrees C. Protective effects of superheated steam against elution loss of nitrogen compounds were also observed in amino acid analyses of the heated products. The scallop-muscle surface temperature during treatment with superheated steam increased more quickly than that with normal steaming and boiling. The rapid water loss and the surface protein denaturation engendered formation of a 30-mum-thick film covering the surface, which prevented extractive nitrogen loss from internal tissues. Superheated steam treatment at 200 degrees C caused browning, surface shrinkage, and 47% weight loss. In marked contrast, the appearance and the weight loss of sample treated at 150 degrees C were almost the same as those of normal steaming and boiling-treated samples. These results suggested that superheated steaming at 150 degrees C is an optimal heat treatment of scallop adductor muscles. PMID:17995678

  3. Superheating of ice crystals in antifreeze protein solutions.

    PubMed

    Celik, Yeliz; Graham, Laurie A; Mok, Yee-Foong; Bar, Maya; Davies, Peter L; Braslavsky, Ido

    2010-03-23

    It has been argued that for antifreeze proteins (AFPs) to stop ice crystal growth, they must irreversibly bind to the ice surface. Surface-adsorbed AFPs should also prevent ice from melting, but to date this has been demonstrated only in a qualitative manner. Here we present the first quantitative measurements of superheating of ice in AFP solutions. Superheated ice crystals were stable for hours above their equilibrium melting point, and the maximum superheating obtained was 0.44 degrees C. When melting commenced in this superheated regime, rapid melting of the crystals from a point on the surface was observed. This increase in melting temperature was more appreciable for hyperactive AFPs compared to the AFPs with moderate antifreeze activity. For each of the AFP solutions that exhibited superheating, the enhancement of the melting temperature was far smaller than the depression of the freezing temperature. The present findings clearly show that AFPs adsorb to ice surfaces as part of their mechanism of action, and this absorption leads to protection of ice against melting as well as freezing. PMID:20215465

  4. Acoustic response of superheated droplet detectors to neutrons

    NASA Astrophysics Data System (ADS)

    Gao, Size; Zhang, Guiying; Ni, Bangfa; Zhao, Changjun; Zhang, Huanqiao; Guan, Yongjing; Chen, Zhe; Xiao, Caijin; Liu, Chao; Liu, Cunxiong

    2012-03-01

    The search for dark matter (DM) is a hot field nowadays, a number of innovative techniques have emerged. The superheated droplet technique is relatively mature; however, it is recently revitalized in a number of frontier fields including the search for DM. In this work, the acoustic response of Superheated Droplet Detectors (SDDs) to neutrons was studied by using a 252Cf neutron source, SDDs developed by the China Institute of Atomic Energy, a sound sensor, a sound card and a PC. Sound signals were filtered. The characteristics of FFT spectra, power spectra and time constants were used to determine the authenticity of the bubbles analyzed.

  5. Thermal Hydraulic Design and Analysis of a Water-Cooled Ceramic Breeder Blanket with Superheated Steam for CFETR

    NASA Astrophysics Data System (ADS)

    Cheng, Xiaoman; Ma, Xuebin; Jiang, Kecheng; Chen, Lei; Huang, Kai; Liu, Songlin

    2015-09-01

    The water-cooled ceramic breeder blanket (WCCB) is one of the blanket candidates for China fusion engineering test reactor (CFETR). In order to improve power generation efficiency and tritium breeding ratio, WCCB with superheated steam is under development. The thermal-hydraulic design is the key to achieve the purpose of safe heat removal and efficient power generation under normal and partial loading operation conditions. In this paper, the coolant flow scheme was designed and one self-developed analytical program was developed, based on a theoretical heat transfer model and empirical correlations. Employing this program, the design and analysis of related thermal-hydraulic parameters were performed under different fusion power conditions. The results indicated that the superheated steam water-cooled blanket is feasible. supported by the National Special Project for Magnetic Confined Nuclear Fusion Energy of China (Nos. 2013GB108004, 2014GB122000 and 2014GB119000), and National Natural Science Foundation of China (No. 11175207)

  6. Replacement of alloy 800H superheated steam line

    SciTech Connect

    Barbier, R.A.; Bullock, J.W.

    1996-07-01

    Sterling Chemicals utilizes alloy 800HT (UNS N08811) piping for superheated steam service in its styrene dehydrogenation unit. An engineering project to replace these lines was recently completed. Material acquisition, shop fabrication, inspection requirements, and field erection will be highlighted in this paper.

  7. Instabilities during liquid migration into superheated hydrothermal systems

    SciTech Connect

    Fitzgerald, Shaun D.; Woods, Andrew W.

    1995-01-26

    Hydrothermal systems typically consist of hot permeable rock which contains either liquid or liquid and saturated steam within the voids. These systems vent fluids at the surface through hot springs, fumaroles, mud pools, steaming ground and geysers. They are simultaneously recharged as meteoric water percolates through the surrounding rock or through the active injection of water at various geothermal reservoirs. In a number of geothermal reservoirs from which significant amounts of hot fluid have been extracted and passed through turbines, superheated regions of vapor have developed. As liquid migrates through a superheated region of a hydrothermal system, some of the liquid vaporizes at a migrating liquid-vapor interface. Using simple physical arguments, and analogue laboratory experiments we show that, under the influence of gravity, the liquid-vapor interface may become unstable and break up into fingers.

  8. Penetration of liquid fingers into superheated fracturedrock

    SciTech Connect

    Birkholzer, Jens

    2002-11-14

    Water infiltrating down a fracture in unsaturated rock experiences complex fluid-flow and heat-transfer phenomena when entering above-boiling rock temperature regions. Such conditions are expected, for example, after emplacement of heat-generating nuclear waste in underground repositories. A new, efficient semi-analytical method is proposed in this paper that simulates the flow processes of infiltration events subject to vigorous boiling from the adjacent hot rock. It is assumed that liquid flow forms in localized preferential flow paths, and that infiltration events are typically short in duration but large in magnitude relative to the average net infiltration. The new solution scheme is applied to several test cases studying sensitivity to a variety of input parameters. Sample simulations are performed for conditions representative of the potential nuclear waste repository at Yucca Mountain, Nevada. A characteristic parameter is introduced that provides a quick estimate of the relative significance of boiling at a given location of interest.

  9. Free surfaces overcome superheating in simulated melting of isotactic polypropylene

    NASA Astrophysics Data System (ADS)

    Chen, Qin; Sirota, Eric B.; Zhang, Min; Chung, T. C. Mike; Milner, Scott T.

    The equilibrium melting point (Tm) is a challenging experimental benchmark for molecular dynamics simulation of polymer melting and crystallization. Tm obtained from melting simulation of α phase isotactic polypropylene (iPP) can exhibit superheating of over 100°C. Superheating has been attributed to the use of periodic boundary conditions and ultrafast simulated heating rates, both of which inhibit melting. We have developed a simple method to overcome superheating; we replace the periodic crystal structure with a periodic array of finite thickness slabs, separated by vacuum gaps. Thermal disorder at the slab surface promotes nucleation of the melt phase. Above Tm, we observe that the melting front advances into the crystal with a velocity proportional to T -Tm . This correspond to a quadratic rise in the system energy versus temperature, at constant heating rate. We obtain Tm as the onset of this quadratic rise in energy, which give values consistent with experimental melting points for iPP oligomers. The same simulations allow reasonable estimates of the crystal-vacuum interfacial free energy, from the energy difference between crystalline slabs and periodic crystals. The authors acknowledge support from National Science Foundation DMR-1507980.

  10. Development of a Parching Machine Using Super-Heated Vapor or Super-Heated High-Moisture Atmosphere

    NASA Astrophysics Data System (ADS)

    Sato, Shoichi; Shinsho, Seiji; Iriki, Hiroyuki; Asai, Junya; Suganuma, Hirofumi; Shibata, Tsutomu

    We developed a new parching machine with super-heated vapor or super-heated highmoisture atmosphere as a heat medium, and investigated the influence exerted on the characteristics of manufactured tea and crude tea quality. (1)We developed machine specifications that improved throughput and allowed us to control stable quality compared with the conventional kamairicha parching machine. (2)The new parching machine could not only manufacture like kamairicha but also achieve various degrees of steaming of products like green tea or heavily steamed sencha. (3)The new parching machine could not only deactivate enzymes but dry leaves. (4)The influence of throughput was great with respect to the grade of pan-parched flavour, which meant that there was a contact opportunity for tea leaves and the surface of machine's wall. (5)Unpleasant smells such as that produced in a summer crop of tea were reduced by the new parching machine.

  11. Origin and transport of chloride in superheated geothermal steam

    USGS Publications Warehouse

    Truesdell, A.H.; Haizlip, J.R.; Armannsson, H.; D'Amore, F.

    1989-01-01

    Hydrogen chloride (HCl) is a known component of some volcanic gases and volcanic-related hydrothermal systems. It has recently been discovered in superheated steam in exploited geothermal systems, usually as a result of HCl-induced corrosion of well casing and steam gathering systems. Evaluation of four geothermal systems (Tatun, Taiwan; Krafla, Iceland; Larderello, Italy and The Geysers, USA) which produce CI-bearing steam provides evidence for the presence of Cl as HCl and the natural reservoir conditions which can produce HCl-bearing steam. Theoretical calculations defining the physical and chemical conditions of the reservoir liquid which can produce HCl-bearing steam are presented. The main factors are pH, temperature and Cl concentration. Lower pH, higher temperature and higher chlorinity allow more HCl to be volatilized with steam. In order to reach the surface in steam, the HCl cannot contact liquid water in which it is more soluble, essentially limiting transport to superheated steam. Temperature, pH and Cl concentration of reservoir liquids in each of the geothermal systems evaluated combine differently to produce HCl-bearing steam. ?? 1989.

  12. LET dependence of bubbles evaporation pulses in superheated emulsion detectors

    NASA Astrophysics Data System (ADS)

    Di Fulvio, Angela; Huang, Jean; Staib, Lawrence; d'Errico, Francesco

    2015-06-01

    Superheated emulsion detectors are suspensions of metastable liquid droplets in a compliant inert medium. Upon interaction with ionizing radiation, the droplets evaporate, generating visible bubbles. Bubble expansion associated with the boiling of the droplets is accompanied by pressure pulses in both the sonic and ultrasonic frequency range. In this work, we analyzed the signal generated by bubble evaporation in the frequency and time domain. We used octafluoropropane (R-218) based emulsions, sensitive to both photons and neutrons. The frequency content of the detected pulses appears to extend well into the hundreds of kHz, beyond the range used in commercial devices to count bubbles as they are formed (typically 1-10 kHz). Kilohertz components characterize the early part of the waveforms, potentially containing information about the energetics of the explosive bubble initial growth phase. The power spectral density of the acoustic signal produced by neutron-induced evaporation shows a characteristic frequency pattern in the 200-400 kHz range, which is not observed when bubbles evaporate upon gamma ray-induced irradiation. For practical applications, detection of ultrasonic pulses associated with the boiling of the superheated drops can be exploited as a fast readout method, negligibly affected by mechanical ambient noise.

  13. Production of superheated steam from vapor-dominated geothermal reservoirs

    USGS Publications Warehouse

    Truesdell, A.H.; White, D.E.

    1973-01-01

    Vapor-dominated geothermal systems such as Larderello, Italy, The Geysers, California, and Matsukawa, Japan yield dry or superheated steam when exploited. Models for these systems are examined along with production data and the thermodynamic properties of water, steam and rock. It is concluded that these systems initially consist of a water and steam filled reservoir, a water-saturated cap rock, and a water or brine-saturated deep reservoir below a water table. Most liquid water in all parts of the system is relatively immobilized in small pores and crevices; steam dominates the large fractures and voids of the reservoir and is the continuous, pressure-controlling phase. With production, the pressure is lowered and the liquid water boils, causing massive transfer of heat from the rock and its eventual drying. Passage of steam through already dried rock produces superheating. After an initial vaporization of liquid water in the reservoir, the decrease in pressure produces increased boiling below the deep water table. With heavy exploitation, boiling extends deeper into hotter rock and the temperature of the steam increases. This model explains most features of the published production behavior of these systems and can be used to guide exploitation policies. ?? 1973.

  14. Melting and superheating of nanowires--a nanotube approach.

    PubMed

    Sar, Dillip Kumar; Nanda, Karuna Kar

    2010-05-21

    We have investigated the size-dependent melting of nanotubes based on a thermodynamic approach and shown that the melting temperature of nanotubes depends on the outer radius and on the inner radius through the thickness of the nanotubes. Size-dependent melting of nanowires and thin films has been derived from that of nanotubes. We validate the size-dependent melting of nanotubes, nanowires and thin films by comparing the results with available molecular dynamic simulations and experimental results. It has also been inferred that superheating occurs when the melting starts from the inner surface and proceeds towards the outer surface, while melting point depression occurs when the melting starts from the outer surface and proceeds towards the inner surface. PMID:20413835

  15. An acoustical bubble counter for superheated drop detectors.

    PubMed

    Taylor, Chris; Montvila, Darius; Flynn, David; Brennan, Christopher; d'Errico, Francesco

    2006-01-01

    A new bubble counter has been developed based on the well-established approach of detecting vaporization events acoustically in superheated drop detectors (SDDs). This counter is called the Framework Scientific ABC 1260, and it represents a major improvement over prior versions of this technology. By utilizing advanced acoustic pattern recognition software, the bubble formation event can be differentiated from ambient background noise, as well as from other acoustic signatures. Additional structural design enhancements include a relocation of the electronic components to the bottom of the device; thus allowing for greater stability, easier access to vial SDDs without exposure to system electronics. Upgrades in the electronics permit an increase in the speed of bubble detection by almost 50%, compared with earlier versions of the counters. By positioning the vial on top of the device, temperature and sound insulation can be accommodated for extreme environments. Lead shells can also be utilized for an enhanced response to high-energy neutrons. PMID:16891351

  16. Ginzburg-Landau theory of the superheating field anisotropy of layered superconductors

    NASA Astrophysics Data System (ADS)

    Liarte, Danilo B.; Transtrum, Mark K.; Sethna, James P.

    2016-10-01

    We investigate the effects of material anisotropy on the superheating field of layered superconductors. We provide an intuitive argument both for the existence of a superheating field, and its dependence on anisotropy, for κ =λ /ξ (the ratio of magnetic to superconducting healing lengths) both large and small. On the one hand, the combination of our estimates with published results using a two-gap model for MgB2 suggests high anisotropy of the superheating field near zero temperature. On the other hand, within Ginzburg-Landau theory for a single gap, we see that the superheating field shows significant anisotropy only when the crystal anisotropy is large and the Ginzburg-Landau parameter κ is small. We then conclude that only small anisotropies in the superheating field are expected for typical unconventional superconductors near the critical temperature. Using a generalized form of Ginzburg Landau theory, we do a quantitative calculation for the anisotropic superheating field by mapping the problem to the isotropic case, and present a phase diagram in terms of anisotropy and κ , showing type I, type II, or mixed behavior (within Ginzburg-Landau theory), and regions where each asymptotic solution is expected. We estimate anisotropies for a number of different materials, and discuss the importance of these results for radio-frequency cavities for particle accelerators.

  17. A multiphysics phase field model on melting and kinetic superheating of aluminum nanolayer and nanoparticle

    NASA Astrophysics Data System (ADS)

    Hwang, Yong Seok

    It has been found during the last decade that a nanoscale melting of metal has very distinctive features compared to its microscale counterpart. It has been observed that a highly non-equilibrium state can result in extreme superheating of a solid state, which cannot be explained well by thermodynamic theories based on equilibrium or nucleation. An endeavor to find the superheating limit and mechanisms of melting and superheating becomes more complicated when various physical phenomena are involved at the similar scales. The main goal of this research is to establish a multiphysics model and to reveal the mechanism of melting and kinetic superheating of a metal nanostructure at high heating rates. The model includes elastodynamics, a fast heating of metal considering a delayed heat transfer between electron gas and lattice phonon and couplings among physical phenomena, and phase transformation incorporated with thermal fluctuation. The model successfully reproduces two independent experiments and several novel nanoscale physical phenomena are discovered. For example, the depression of the melting temperature of Al nanolayer under plane stress condition, the threshold heating rate, 1011 K/s, for kinetic superheating, a large temperature drop in a 5 nm collision region of the two solid-melt interfaces, and a strong effect of geometry on kinetic superheating in Al core-shell nanostructure at high heating rate.

  18. Neutron spectrometry in mixed fields: superheated drop (bubble) detectors.

    PubMed

    d'Errico, F; Matzke, M

    2003-01-01

    The BINS neutron threshold spectrometer permits the analysis of the main features of a neutron field for radiation protection purposes. The system offers a virtually complete photon discrimination and nested threshold responses to neutrons, which allow the use of very effective 'few-channel' unfolding procedures. To date, the practical operating energy range of a BINS is 0.1-10 MeV, over which a resolving power of 20-30% can be expected when the deconvolution is performed without explicit pre-information. Spectrum unfolding results in relatively high uncertainties on the differential fluence distributions, but due to negative correlations in adjacent energy groups the uncertainties on integral quantities such as dose equivalent are small and of the order of 5% to 10%, similar to the results of other active spectrometers. In comparison with most radiation detectors, the BINS is an extremely slow system due to the intrinsic duration of a bubble pulse and to the time associated with pulse analysis. For example, the maximum sustainable fluence rate of 1 MeV neutrons is about 10(4) cm(-2) s(-1), which is low for many neutron physics experiments. However, this rate corresponds to an ambient dose equivalent rate of about 1 mSv h(-1), making the active device adequate for radiation protection applications in the workplaces described in Section 1. There are ample margins for improvement of the spectrometer. In particular, in the low-energy region a thermal-epithermal neutron group may be added by using chlorine-bearing emulsions stabilised at suitable temperatures. In fact, the latest version of the system achieves this goal by using a single superheated emulsion of dichlorotetrafluoroethane (R-114) operated at temperatures up to 55 degrees C. This extends the range of the spectrometer and at the same time removes the undue enhancement of the UNFANA output in the low energy region. Above 10 MeV, the resolution can be improved by adding more thresholds, e.g. by starting from

  19. Wicking of liquid nitrogen into superheated porous structures

    NASA Astrophysics Data System (ADS)

    Grebenyuk, Yulia; Dreyer, Michael E.

    2016-09-01

    Evaporation in porous elements of liquid-vapor separation devices can affect the vapor-free cryogenic propellant delivery to spacecraft engines. On that account, the capillary transport of a cryogenic liquid subjected to evaporation needs to be understood and assessed. We investigate wicking of liquid nitrogen at saturation temperature into superheated porous media. A novel test facility was built to perform wicking experiments in a one-species system under non-isothermal conditions. A setup configuration enabled to define the sample superheat by its initial position in a stratified nitrogen vapor environment inside the cryostat. Simultaneous sample weight and temperature measurements indicated the wicking front velocity. The mass of the imbibed liquid nitrogen was determined varying the sample superheat, geometry and porous structure. To the author's extent of knowledge, these are the first wicking experiments performed with cryogenic fluids subjected to evaporation using the weight-time measurement technique. A one-dimensional macroscopic model describes the process theoretically. Results revealed that the liquid loss due to evaporation at high sample superheats leads to only a slight imbibition rate decrease. However, the imbibition rate can be greatly affected by the vapor flow created due to evaporation that counteracts the wicking front propagation.

  20. Speciation and chemical activities in superheated sodium borate solutions

    SciTech Connect

    Weres, O. )

    1993-06-01

    The system H[sub 2]O-B[sub 2]O[sub 3]-Na[sub 2]O has been studied experimentally at 277[degrees] and 317[degrees]C. The activities of water and boric acid have been determined at mole ratios Na/B from 0 to 1.5, and total dissolved solids 3 to 80 weight percent. The activity of boric acid has been fitted to within experimental error using a speciation model with eight complex species. This model is consistent with the model previously published by Mesmer et al. The electrolyte properties of the liquid are modelled using the Pitzer-Simonson Model of very concentrated electrolyte solutions. The calculated values of water activity agree with experiment, and the activity of NaOH and pOH have also been calculated. These data will allow prediction of the composition and chemical behavior of sodium borate liquids that may accumulate in the superheated crevices within a steam generator. A modified form of the model is provided for use with MULTEQ. The potassium borate system also was briefly studied at 317[degrees]C, and is adequately described by a model with five complex species. The potassium borate liquid is more alkaline at K/B = 1 than a sodium borate liquid at the same mole ratio, but pOH in the two systems is the same at lower mole ratios.

  1. Mathematical Modeling of Ultra-Superheated Steam Gasification

    NASA Astrophysics Data System (ADS)

    Xin, Fen

    Pure steam gasification has been of interest in hydrogen production, but with the challenge of supplying heat for endothermic reactions. Traditional solutions included either combusting feedstocks at the price of decreasing carbon conversion ratio, or using costly heating apparatus. Therefore, a distributed gasifier with an Ultra-Superheated-Steam (USS) generator was invented, satisfying the heat requirement and avoiding carbon combustion in steam gasification. This project developed the first version of the Ultra-Superheated-Steam-Fluidization-Model (USSFM V1.0) for the USS gasifier. A stand-alone equilibrium combustion model was firstly developed to calculate the USS mixture, which was the input to the USSFM V1.0. Model development of the USSFM V1.0 included assumptions, governing equations, boundary conditions, supporting equations and iterative schemes of guessed values. There were three nested loops in the dense bed and one loop in the freeboard. The USSFM V1.0 included one main routine and twenty-four subroutines. The USSFM V1.0 was validated with experimental data from the Enercon USS gasifier. The calculated USS mixture had a trace of oxygen, validating the initial expectation of creating an oxygen-free environment in the gasifier. Simulations showed that the USS mixture could satisfy the gasification heat requirement without partial carbon combustion. The USSFM V1.0 had good predictions on the H2% in all tests, and on other variables at a level of the lower oxygen feed. Provided with higher oxygen feed, the USSFM V1.0 simulated hotter temperatures, higher CO% and lower CO2%. Errors were explained by assumptions of equilibrium combustion, adiabatic reactors, reaction kinetics, etc. By investigating specific modeling data, gas-particle convective heat transfers were found to be critical in energy balance equations of both emulsion gas and particles, while bubble size controlled both the mass and energy balance equations of bubble gas. Parametric study

  2. An experimental study of evaporation waves in a superheated liquid

    NASA Astrophysics Data System (ADS)

    Hill, Larry G.

    1990-01-01

    Evaporation waves in superheated liquids are studied using a rapid-depressurization facility consisting of a vertical glass test cell situated beneath a large, low-pressure reservoir. The objective of this study is to learn more about the physical mechanisms of explosive boiling (of which an evaporation wave is a specific example), as well as properties of the flow it produces.The test cell is initially sealed from the reservoir by a foil diaphragm, and is partially filled with a volatile liquid (Refrigerant 12 or 114). An experiment is initiated by rupturing the diaphragm via a pneumatically driven cutter. The instrumentation consists of fast-response pressure measurements, high-speed motion pictures, and spark-illuminated still photographs. The liquid temperature is typically 20°C; the liquid superheat is controlled by setting the reservoir pressure to values between vacuum and 1 atm. The pressures subsequent to depressurization are very much less than the critical pressure, and the initial temperatures are sufficiently low that, although the test liquid is highly superheated, the superheat limit is not approached. Evaporation waves in which bubble nucleation within the liquid column is suppressed entirely are considered almost exclusively.When the diaphragm is ruptured, the liquid pressure drops to virtually the reservoir value within a few milliseconds. Provided that the liquid superheat so obtained is sufficiently high, the free surface then erupts in a process known as explosive boiling, which is characterized by violent, fine-scale fragmentation of the superheated liquid and extremely rapid evaporation. The explosive boiling process proceeds as a "wavefront" into the liquid column, producing a highspeed, two-phase flow that travels upward into the low-pressure reservoir, emptying the test cell in a few hundred milliseconds. The speed of the wavefront varies between 0.2 and 0.6 m/s, depending on run conditions; the corresponding two-phase flow varies between

  3. Stability Criteria and Thermodynamic Properties of Superheated Crystal

    NASA Astrophysics Data System (ADS)

    Norman, Guenri; Stegailov, Vladimir

    2002-08-01

    Molecular dynamics method [1-3] is used for the study of equation of state, heat capacity and elastic moduli of superheated model crystal. Thermodynamic, mechanic and kinetic limits of stability are investigated. Fcc-lattice of N particles interacting via U=ɛ(σ/r)^n potential is simulated with the periodic boundary conditions. In this case system properties depend only on a single parameter X ˜ ρσ^3(ɛ/k_BT)^3/n, where ρ - density, T - temperature. This potential was used for simulation of liquid and solid metals, high pressure range included [3]. Only fragments of MD-runs before beginning of melting are used for averaging in order to obtain pressure, temperature, isothermal compressibility, heat capacity and elastic moduli. Different values of n are treated. Inequality (partialP/partialV)_T<0 should be valid for the thermodynamic stability. Mechanic stability is related to the conditions for elastic moduli. Estimation of the maximum nucleation rate allows us to obtain the corresponding kinetic limit (X-1)_max of crystal stability. Our results point to the close values of (X-1)_max obtained for three different stability limits. Results are used for the calculation of the spinodal of solid copper. The work is supported by RFBR (00-02-16310a, 02-02-06654mas) and Integratsiya (U0022). [1] Z.H. Jin et al. PRL 87 (2001) 055703. [2] M.N. Krivoguz, G.E. Norman Doklady Physics 46 (2001) 463. [3] W.G. Hoover et al. J. Chem Phys. 63 (1975) 5434.

  4. Superheated-steam test of ethylene propylene rubber cables using a simultaneous aging and accident environment

    SciTech Connect

    Bennett, P.R.; St. Clair, S.D.; Gilmore, T.W.

    1986-06-01

    The superheated-steam test exposed different ethylene propylene rubber (EPR) cables and insulation specimens to simultaneous aging and a 21-day simultaneous accident environment. In addition, some insulation specimens were exposed to five different aging conditions prior to the 21-day simultaneous accident simulation. The purpose of this superheated-steam test (a follow-on to the saturated-steam tests (NUREG/CR-3538)) was to: (1) examine electrical degradation of different configurations of EPR cables; (2) investigate differences between using superheated-steam or saturated-steam at the start of an accident simulation; (3) determine whether the aging technique used in the saturated-steam test induced artificial degradation; and (4) identify the constituents in EPR that affect moisture absorption.

  5. Prediction and experimental confirmation of the response function for neutron detection using superheated drops

    NASA Astrophysics Data System (ADS)

    Lo, Yuan-Chyuan; Apfel, Robert E.

    1988-11-01

    Neutrons can be detected with a suspension of superheated drops in an immiscible and compliant holding medium. The mechanism of this radiation-induced bubble nucleation has been studied. A model to predict the minimum neutron energy required to nucleate a vapor bubble in superheated liquids has previously been reported [R.E. Apfel, S. C. Roy, and Y.-C. Lo, Phys. Rev. A 31, 3194 (1985)]. Now, the energy-dependent response function for the detector has been calculated based on the model and a detailed consideration of the possible interactions of neutrons with superheated materials. The response of the detector has been measured with monoenergetic neutrons (from 0.025 eV to 14 MeV) at facilities of the National Bureau of Standards and the Radiological Research Accelerator Facility at the Nevis Laboratories of Columbia University. The experimental results agree reasonably well with that of the calculations.

  6. Rapid Generation of Superheated Steam Using a Water-containing Porous Material

    NASA Astrophysics Data System (ADS)

    Mori, Shoji; Okuyama, Kunito

    Heat treatment by superheated steam has been utilized in several industrial fields including sterilization, desiccation, and cooking. In particular, cooking by superheated steam is receiving increased attention because it has advantages of reducing the salt and fat contents in foods as well as suppressing the oxidation of vitamin C and fat. In this application, quick startup and cut-off responses are required. Most electrically energized steam generators require a relatively long time to generate superheated steam due to the large heat capacities of the water in container and of the heater. Zhao and Liao (2002) introduced a novel process for rapid vaporization of subcooled liquid, in which a low-thermal-conductivity porous wick containing water is heated by a downward-facing grooved heating block in contact with the upper surface of the wick structure. They showed that saturated steam is generated within approximately 30 seconds from room-temperature water at a heat flux 41.2 kW⁄m2. In order to quickly generate superheated steam of approximately 300°C, which is required for cooking, the heat capacity of the heater should be as small as possible and the imposed heat flux should be so high enough that the porous wick is able to dry out in the vicinity of the contact with the heater and that the resulting heater temperature becomes much higher than the saturation temperature. The present paper proposes a simple structured generator to quickly produce superheated steam. Only a fine wire heater is contacted spirally on the inside wall in a hollow porous material. The start-up, cut-off responses and the rate of energy conversion for input power are investigated experimentally. Superheated steam of 300°C is produced in approximately 19 seconds from room-temperature water for an input power of 300 W. The maximum rate of energy conversion in the steady state is approximately 0.9.

  7. Solid Superheating Observed in Two-Dimensional Strongly Coupled Dusty Plasma

    SciTech Connect

    Feng Yan; Goree, J.; Liu Bin

    2008-05-23

    It is demonstrated experimentally that strongly coupled plasma exhibits solid superheating. A 2D suspension of microspheres in dusty plasma, initially self-organized in a solid lattice, was heated and then cooled rapidly by turning laser heating on and off. Particles were tracked using video microscopy, allowing atomistic-scale observation during melting and solidification. During rapid heating, the suspension remained in a solid structure at temperatures above the melting point, demonstrating solid superheating. Hysteresis diagrams did not indicate liquid supercooling in this 2D system.

  8. Imaging the Homogeneous Nucleation During the Melting of Superheated Colloidal Crystals

    NASA Astrophysics Data System (ADS)

    Wang, Ziren; Wang, Feng; Peng, Yi; Zheng, Zhongyu; Han, Yilong

    2012-10-01

    The nucleation process is crucial to many phase transitions, but its kinetics are difficult to predict and measure. We superheated and melted the interior of thermal-sensitive colloidal crystals and investigated by means of video microscopy the homogeneous melting at single-particle resolution. The observed nucleation precursor was local particle-exchange loops surrounded by particles with large displacement amplitudes rather than any defects. The critical size, incubation time, and shape and size evolutions of the nucleus were measured. They deviate from the classical nucleation theory under strong superheating, mainly because of the coalescence of nuclei. The superheat limit agrees with the measured Born and Lindemann instabilities.

  9. Melting and superheating of sI methane hydrate: molecular dynamics study.

    PubMed

    Smirnov, Grigory S; Stegailov, Vladimir V

    2012-01-28

    Melting and decay of the superheated sI methane structure are studied using molecular dynamics simulation. The melting curve is calculated by the direct coexistence simulations in a wide range of pressures up to 5000 bar for the SPC/E, TIP4P/2005 and TIP4P/Ice water models and the united-atom model for methane. We locate the kinetic stability boundary of the superheated metastable sI structure that is found to be surprisingly high comparing with the predictions based on the classical nucleation theory. PMID:22299907

  10. Experimental investigations of beet pulp drying in superheated steam under pressure

    SciTech Connect

    Urbaniec, K.; Malczewski, J.

    1997-10-01

    Beet pulp drying in superheated steam under pressure makes it possible to save energy in sugar factories. A new concept of a two-stage convective steam drier is presented. To obtain kinetic data on beet pulp drying, an experimental setup was built. Beet pulp samples were dried at steam pressure up to 4 bar and temperature up to 220 C.

  11. Inhibition of lipid oxidation in pork bundles processing by superheated steam frying.

    PubMed

    Huang, Tzou-Chi; Ho, Chi-Tang; Fu, Hui-Yin

    2004-05-19

    The effect of superheated steam treatment on the oxidative stability of lipids in packaged Zousoon (pork bundles) was investigated. The aroma quality of Zousoon samples was evaluated by sensory analysis and chromatographic analysis of volatiles. Results of this study indicated that oxidation of lipids occurred in pan-fried Zousoon after prolonged storage. Significant amounts of highly volatile compounds such as formaldehyde, acetaldehyde, acetone, and hexanal in Zousoon were identified by a modified method of cysteamine derivatization followed by gas chromatography-mass spectrometry (GC-MS) analysis. Superheated steam was found to be effective in suppressing lipid oxidation in canned Zousoon as compared with Zousoon fried by the conventional method in a frying pan. The superheated steam-fried samples had relatively low thiobarbituric acid reactive substance (TBARS) and peroxide (POV) values before and after storage, whereas samples prepared by pan frying had relatively high TBARS and POV values before and after storage. Superheated steam-fried Zousoon had superior lipid stability to that prepared by the conventional pan-frying method.

  12. Application and energy saving potential of superheated steam drying in the food industry

    SciTech Connect

    Fitzpatrick, J.; Robinson, A.

    1996-12-31

    The possibilities of using superheated steam in heat and mass transfer processes such as drying have lately been investigated and tested by several industries. The mode of operation, energy saving potential, advantages of and problems with this media in contact with foodstuffs and food waste sludge are discussed in this article.

  13. The Reaction of Carbonates in Contact with Superheated Silicate Melts: New Insights from MEMIN Laser Melting Experiments

    NASA Astrophysics Data System (ADS)

    Hamann, C.; Hecht, L.; Schäffer, S.; Deutsch, A.; Lexow, B.

    2016-08-01

    The reaction of carbonates in contact with silicate impact melts is discussed quite controversially in the impact community. Here, we discuss four MEMIN laser melting experiments involving carbonates in contact with superheated silicate melts.

  14. Comparative Study on the Effects of Boiling, Steaming, Grilling, Microwaving and Superheated Steaming on Quality Characteristics of Marinated Chicken Steak

    PubMed Central

    Choi, Yun-Sang; Kim, Young-Boong; Jeon, Ki-Hong; Kim, Eun-Mi; Sung, Jung-Min; Kim, Hyun-Wook

    2016-01-01

    The effects of five different cooking methods (boiling, steaming, grilling, microwaving, and superheated steaming) on proximate composition, pH, color, cooking loss, textural properties, and sensory characteristics of chicken steak were studied. Moisture content and lightness value (L*-value) were higher in superheated steam cooked chicken steak than that of the other cooking treatments such as boiling, steaming, grilling and microwaving cooking (p<0.05), whereas protein content, redness value (a*-value), hardness, gumminess, and chewiness of superheated steam cooked chicken steak was lower than that in the other cooking treatments (p<0.05). Fat content and ash content, springiness, and cohesiveness were not significantly different among the chicken steak cooked using various methods (p>0.05). Among the sensory characteristics, tenderness score, juiciness score and overall acceptability score were the highest for the superheated steam samples (p<0.05), whereas no difference in flavor scores were observed among the other treatments (p>0.05). These results show that marinated chicken steak treated with superheated steam in a preheated 250℃ oven and 380℃ steam for 5 min until core temperature reached 75℃ improved the quality characteristics and sensory properties the best. Therefore, superheated steam was useful to improve cooked chicken steak. PMID:27499656

  15. Comparative Study on the Effects of Boiling, Steaming, Grilling, Microwaving and Superheated Steaming on Quality Characteristics of Marinated Chicken Steak.

    PubMed

    Choi, Yun-Sang; Hwang, Ko-Eun; Jeong, Tae-Jun; Kim, Young-Boong; Jeon, Ki-Hong; Kim, Eun-Mi; Sung, Jung-Min; Kim, Hyun-Wook; Kim, Cheon-Jei

    2016-01-01

    The effects of five different cooking methods (boiling, steaming, grilling, microwaving, and superheated steaming) on proximate composition, pH, color, cooking loss, textural properties, and sensory characteristics of chicken steak were studied. Moisture content and lightness value (L*-value) were higher in superheated steam cooked chicken steak than that of the other cooking treatments such as boiling, steaming, grilling and microwaving cooking (p<0.05), whereas protein content, redness value (a*-value), hardness, gumminess, and chewiness of superheated steam cooked chicken steak was lower than that in the other cooking treatments (p<0.05). Fat content and ash content, springiness, and cohesiveness were not significantly different among the chicken steak cooked using various methods (p>0.05). Among the sensory characteristics, tenderness score, juiciness score and overall acceptability score were the highest for the superheated steam samples (p<0.05), whereas no difference in flavor scores were observed among the other treatments (p>0.05). These results show that marinated chicken steak treated with superheated steam in a preheated 250℃ oven and 380℃ steam for 5 min until core temperature reached 75℃ improved the quality characteristics and sensory properties the best. Therefore, superheated steam was useful to improve cooked chicken steak.

  16. Comparative Study on the Effects of Boiling, Steaming, Grilling, Microwaving and Superheated Steaming on Quality Characteristics of Marinated Chicken Steak.

    PubMed

    Choi, Yun-Sang; Hwang, Ko-Eun; Jeong, Tae-Jun; Kim, Young-Boong; Jeon, Ki-Hong; Kim, Eun-Mi; Sung, Jung-Min; Kim, Hyun-Wook; Kim, Cheon-Jei

    2016-01-01

    The effects of five different cooking methods (boiling, steaming, grilling, microwaving, and superheated steaming) on proximate composition, pH, color, cooking loss, textural properties, and sensory characteristics of chicken steak were studied. Moisture content and lightness value (L*-value) were higher in superheated steam cooked chicken steak than that of the other cooking treatments such as boiling, steaming, grilling and microwaving cooking (p<0.05), whereas protein content, redness value (a*-value), hardness, gumminess, and chewiness of superheated steam cooked chicken steak was lower than that in the other cooking treatments (p<0.05). Fat content and ash content, springiness, and cohesiveness were not significantly different among the chicken steak cooked using various methods (p>0.05). Among the sensory characteristics, tenderness score, juiciness score and overall acceptability score were the highest for the superheated steam samples (p<0.05), whereas no difference in flavor scores were observed among the other treatments (p>0.05). These results show that marinated chicken steak treated with superheated steam in a preheated 250℃ oven and 380℃ steam for 5 min until core temperature reached 75℃ improved the quality characteristics and sensory properties the best. Therefore, superheated steam was useful to improve cooked chicken steak. PMID:27499656

  17. Superheated water as chromatographic eluent for parabens separation on octadecyl coated zirconia stationary phase.

    PubMed

    Dugo, Paola; Buonasera, Katia; Crupi, Maria Lucia; Cacciola, Francesco; Dugo, Giovanni; Mondello, Luigi

    2007-05-01

    In this study, the use of pure water at superheated temperatures, between 100 and 200 degrees C, as a mobile phase for RP separation is explored. Instrumental parameters, such as temperature, flow rate, preheating and cooling, have shown significant effects on the quality of the chromatographic peaks. The properties of superheated water as an eluent were investigated by observing the chromatographic behaviour of four parabens on a carbon-clad zirconia (ZR) phase with covalently bonded octadecyl groups. Results were compared with those obtained at 30 degrees C on a silica-based phase with octadecyl groups, using water and ACN as mobile phase. The optimized method was finally applied to analyse parabens in a commercial body cream. PMID:17595947

  18. Superheated liquid extraction of oleuropein and related biophenols from olive leaves.

    PubMed

    Japón-Luján, R; Luque de Castro, M D

    2006-12-15

    Oleuropein and other healthy olive biophenols (OBPs) such as verbacoside, apigenin-7-glucoside and luteolin-7-glucoside have been extracted from olive leaves by using superheated liquids and a static-dynamic approach. Multivariate methodology has been used to carry out a detailed optimisation of the extraction. Under the optimal working conditions, complete removal without degradation of the target analytes was achieved in 13 min. The extract was injected into a chromatograph-photodiode array detector assembly for individual separation-quantification. The proposed approach - which provides more concentrated extracts than previous alternatives - is very useful to study matrix-extractant analytes partition. In addition, the efficacy of superheated liquids to extract OBPs, the simplicity of the experimental setup, its easy automation and low acquisition and maintenance costs make the industrial implementation of the proposed method advisable.

  19. Nonlinear dynamics of a vapor bubble expanding in a superheated region of finite size

    NASA Astrophysics Data System (ADS)

    Annenkova, E. A.; Kreider, W.; Sapozhnikov, O. A.

    2015-10-01

    Growth of a vapor bubble in a superheated liquid is studied theoretically. Contrary to the typical situation of boiling, when bubbles grow in a uniformly heated liquid, here the superheated region is considered in the form of a millimeter-sized spherical hot spot. An initial micron-sized bubble is positioned at the hot spot center and a theoretical model is developed that is capable of studying bubble growth caused by vapor pressure inside the bubble and corresponding hydrodynamic and thermal processes in the surrounding liquid. Such a situation is relevant to the dynamics of vapor cavities that are created in soft biological tissue in the focal region of a high-intensity focused ultrasound beam with a shocked pressure waveform. Such beams are used in the recently proposed treatment called boiling histotripsy. Knowing the typical behavior of vapor cavities during boiling histotripsy could help to optimize the therapeutic procedure.

  20. Nonlinear dynamics of a vapor bubble expanding in a superheated region of finite size

    SciTech Connect

    Annenkova, E. A.; Kreider, W.; Sapozhnikov, O. A.

    2015-10-28

    Growth of a vapor bubble in a superheated liquid is studied theoretically. Contrary to the typical situation of boiling, when bubbles grow in a uniformly heated liquid, here the superheated region is considered in the form of a millimeter-sized spherical hot spot. An initial micron-sized bubble is positioned at the hot spot center and a theoretical model is developed that is capable of studying bubble growth caused by vapor pressure inside the bubble and corresponding hydrodynamic and thermal processes in the surrounding liquid. Such a situation is relevant to the dynamics of vapor cavities that are created in soft biological tissue in the focal region of a high-intensity focused ultrasound beam with a shocked pressure waveform. Such beams are used in the recently proposed treatment called boiling histotripsy. Knowing the typical behavior of vapor cavities during boiling histotripsy could help to optimize the therapeutic procedure.

  1. Superheated liquid extraction of oleuropein and related biophenols from olive leaves.

    PubMed

    Japón-Luján, R; Luque de Castro, M D

    2006-12-15

    Oleuropein and other healthy olive biophenols (OBPs) such as verbacoside, apigenin-7-glucoside and luteolin-7-glucoside have been extracted from olive leaves by using superheated liquids and a static-dynamic approach. Multivariate methodology has been used to carry out a detailed optimisation of the extraction. Under the optimal working conditions, complete removal without degradation of the target analytes was achieved in 13 min. The extract was injected into a chromatograph-photodiode array detector assembly for individual separation-quantification. The proposed approach - which provides more concentrated extracts than previous alternatives - is very useful to study matrix-extractant analytes partition. In addition, the efficacy of superheated liquids to extract OBPs, the simplicity of the experimental setup, its easy automation and low acquisition and maintenance costs make the industrial implementation of the proposed method advisable. PMID:17045596

  2. Melting Kinetics of Confined Systems at the Nanoscale: Superheating and Supercooling

    SciTech Connect

    Sharp, I. D.; Xu, Q.; Yuan, C. W.; Liao, C. Y.; Glaeser, A. M.; Chrzan, D. C.; Haller, E. E.; Yi, D. O.; Minor, A. M.; Beeman, J. W.; Ager, J. W. III; Ridgway, M. C.; Kluth, P.

    2007-04-10

    In situ electron diffraction measurements of silica-embedded Ge nanocrystals reveal a melting/solidification hysteresis of 470 K which is approximately symmetric about the bulk melting point. This surprising behavior, which is thought to be impossible in bulk systems, is well described by a simple, classical thermodynamic model. Surface pre-melting, which occurs for materials with free surfaces, is suppressed by the presence of the host matrix, thereby allowing both kinetic supercooling and kinetic superheating of the embedded nanocrystals.

  3. Superheating Suppresses Structural Disorder in Layered BiI3 Semiconductors Grown by the Bridgman Method

    SciTech Connect

    Johns, Paul M.; Sulekar, Soumitra; Yeo, Shinyoung; Baciak, James E.; Bliss, Mary; Nino, Juan C.

    2016-01-01

    The susceptibility of layered structures to stacking faults is a problem in some of the more attractive semiconductor materials for ambient-temperature radiation detectors. In the work presented here, Bridgman-grown BiI3 layered single crystals are investigated to understand and eliminate this structural disorder, which reduces radiation detector performance. The use of superheating gradients has been shown to improve crystal quality in non-layered semiconductor crystals; thus the technique was here explored to improve the growth of BiI3. When investigating the homogeneity of non-superheated crystals, highly geometric void defects were found to populate the bulk of the crystals. Applying a superheating gradient to the melt prior to crystal growth improved structural quality and decreased defect density from the order of 4600 voids per cm3 to 300 voids per cm3. Corresponding moderate improvements to electronic properties also resulted from the superheat gradient method of crystal growth. Comparative measurements through infrared microscopy, etch-pit density, x-ray rocking curves, and sheet resistivity readings show that superheat gradients in BiI3 growth led to higher quality crystals.

  4. Quenching of a highly superheated porous medium by injection of water

    NASA Astrophysics Data System (ADS)

    Fichot, F.; Bachrata, A.; Repetto, G.; Fleurot, J.; Quintard, M.

    2012-11-01

    Understanding of two-phase flow through porous medium with intense phase change is of interest in many situations, including nuclear, chemical or geophysical applications. Intense boiling occurs when the liquid is injected into a highly superheated medium. Under such conditions, the heat flux extracted by the fluid from the porous medium is mainly governed by the nucleation of bubbles and by the evaporation of thin liquid films. Both configurations are possible, depending on local flow conditions and on the ratio of bubble size to pore size. The present study is motivated by the safety evaluation of light water nuclear reactors in case of a severe accident scenario, such as the one that happened in Fukushima Dai-ichi plant in March, 2011. If water sources are not available for a long period of time, the reactor core heats up due to the residual power and eventually becomes significantly damaged due to intense oxidation of metals and fragmentation of fuel rods resulting in the formation of a porous medium where the particles have a characteristic length-scale of 1 to 5 mm. The coolability of the porous medium will depend on the water flow rate which can enter the medium under the available driving head and on the geometrical features of the porous matrix (average pore size, porosity). Therefore, it is of high interest to evaluate the conditions for which the injection of water in such porous medium is likely to stop the progression of the accident. The present paper addresses the issue of modelling two-phase flow and heat transfers in a porous medium initially dry, where water is injected. The medium is initially at a temperature well above the saturation temperature of water. In a first part, a summary of existing knowledge is provided, showing the scarcity of models and experimental data. In a second part, new experimental results obtained in an IRSN facility are analysed. The experiment consists in a bed of steel particles that are heated up to 700

  5. Morphology of ejected debris from laser super-heated fused silica following exit surface laser-induced damage

    NASA Astrophysics Data System (ADS)

    Demos, Stavros G.; Negres, Raluca A.; Raman, Rajesh N.; Feit, Michael D.; Manes, Kenneth R.; Rubenchik, Alexander M.

    2015-11-01

    Laser induced damage (breakdown) initiated on the exit surface of transparent dielectric materials using nanosecond pulses creates a volume of superheated material reaching localized temperatures on the order of 1 eV and pressures on the order of 10 GPa or larger. This leads to material ejection and the formation of a crater. The volume of this superheated material depends largely on the laser parameters such as fluence and pulse duration. To elucidate the material behaviors involved, we examined the morphologies of the ejected superheated material particles and found distinctive morphologies. We hypothesize that these morphologies arise from the difference in the structure and physical properties (such as the dynamic viscosity and presence of instabilities) of the superheated material at the time of ejection of each individual particle. Some of the ejected particles are on the order of 1 µm in diameter and appear as "droplets". Another subgroup appears to have stretched, foam-like structure that can be described as material globules interconnected via smaller in diameter columns. Such particles often contain nanometer size fibers attached on their surface. In other cases, only the globules have been preserved suggesting that they may be associated with a collapsed foam structure under the dynamic pressure as it traverses in air. These distinct features originate in the structure of the superheated material during volume boiling just prior to the ejection of the particles.

  6. A response function calculation for a dose-equivalent neutron dosimeter using superheated drops

    SciTech Connect

    Wang, C.K. )

    1991-01-01

    A neutron dosimeter using superheated drops in gel was invented by Apfel. The SDD-100 or BD-100, which uses Freon-12 (CF{sub 2}Cl{sub 2}) for the superheated drops, is most useful in neutron dosimetry because it was claimed that the neutron response function of such a dosimeter is nearly dose equivalent. An ideal dose-equivalent neutron dosimeter should be totally independent of the energies of incident neutrons. Lo and Apfel have performed calculations and experiments to study the neutron response functions for various types of superheated drops, including Freon-12. Both their calculational and the experimental results demonstrated the dose-equivalent-like response function for the Freon-12. The agreement between the calculational results and the experimental results is not satisfactory, however, especially for neutrons with energies < 100 keV. One important factor, which was not considered and may have contributed to the disagreement, is the neutron-slowing-down effect. That is, kilo-electron-volt neutrons, although not energetic enough to trigger bubbles in Freon-12, have a short mean-free-path (< 1 cm) and can easily slow down or thermalize in the gel matrix and then trigger bubbles in Freon-12 via a {sup 35}Cl(n,p){sup 35}S reaction. To consider the slowing-down effect in the dosimeter, a neutron transport calculation must be performed. This paper describes the set of Monte Carlo neutron transport calculations that were performed to calculate the response function for a bare SDD-100 surrounded with various thicknesses of polyethylene (CH{sub 2}).

  7. First dark matter limits from a large-mass, low-background, superheated droplet detector.

    PubMed

    Collar, J I; Puibasset, J; Girard, T A; Limagne, D; Miley, H S; Waysand, G

    2000-10-01

    We report on the fabrication aspects and calibration of the first large active mass ( approximately 15 g) modules of SIMPLE, a search for particle dark matter using superheated droplet detectors (SDDs). While still limited by the statistical uncertainty of the small data sample on hand, the first weeks of operation in the new underground laboratory of Rustrel-Pays d'Apt already provide a sensitivity to axially coupled weakly interacting massive particles (WIMPs) competitive with leading experiments, confirming SDDs as a convenient, low-cost alternative for WIMP detection. PMID:11019272

  8. Investigation of spray characteristics for flashing injection of fuels containing dissolved air and superheated fuels

    NASA Technical Reports Server (NTRS)

    Solomon, A. S. P.; Chen, L. D.; Faeth, G. M.

    1982-01-01

    The flow, atomization and spreading of flashing injector flowing liquids containing dissolved gases (jet/air) as well as superheated liquids (Freon II) were considered. The use of a two stage expansion process separated by an expansion chamber, ws found to be beneficial for flashing injection particularly for dissolved gas systems. Both locally homogeneous and separated flow models provided good predictions of injector flow properties. Conventional correlations for drop sizes from pressure atomized and airblast injectors were successfully modified, using the separated flow model to prescribe injector exit conditions, to correlate drop size measurements. Additional experimental results are provided for spray angle and combustion properties of sprays from flashing injectors.

  9. Extraction of amino acids from soils and sediments with superheated water

    NASA Technical Reports Server (NTRS)

    Cheng, C. N.; Ponnamperuma, C.

    1974-01-01

    A method of extraction for amino acids from soils and sediments involving superheated water has been investigated. About 75-97 per cent of the amino acids contained in four soils of a soil profile from Illinois were extracted by this method. Deep penetration of water into soil aggregates and partial hydrolysis of peptide bonds during this extraction by water at high temperature are likely mechanisms responsible for the release of amino acids from samples. This extraction method does not require subsequent desalting treatments when analyses are carried out with an ion-exchange amino acid analyzer.

  10. Liquid level, void fraction, and superheated steam sensor for nuclear reactor cores

    DOEpatents

    Tokarz, Richard D.

    1983-01-01

    An apparatus for detecting nominal phase conditions of coolant in a reactor vessel comprising one or more lengths of tubing each leading from a location being monitored to a closed outer end exterior of the vessel. Temperature is sensed at the open end of each length of tubing. Pressure within the tubing is also sensed. Both measurements are directed to an analyzer which compares the measured temperature to the known saturated temperature of the coolant at the measured pressure. In this manner, the nominal phase conditions of the coolant are constantly monitored.

  11. Superheating of Crystalline Solids: Theory, Experiment, Simulation and Applications to Static and Dynamic High-pressure Melting

    NASA Astrophysics Data System (ADS)

    Luo, S.; Ahrens, T. J.; Cagin, T.; Strachan, A.; Goddard, W. A.

    2002-12-01

    Systematics of superheating (Θ =Δ T/Tm, where Δ T is the amount of superheating and Tm melting temperature) of crystalline solids as a function of heating rate (Q) are established by defining a dimensionless energy barrier for nucleation, β=16π γsl3/(3kTmΔ Hm2) where γsl is the solid-liquid interfacial energy, Δ Hm is the heat of fusion and k Boltzmann constant. Under conditions that lead to homogeneous nucleation (e.g., ultrafast internal heating), superheating is more pronounced. Sound speed and shock temperature measurements on various materials (Fe, V, Mo, Ta, W, CsBr, KBr, SiO2, and Mg2SiO4) under planar impact (Q~ 1012 K/s) leads to superheating of Θ =0.2-0.6. Comparable superheating was achieved during intense laser irradiation (Q~ 1012-1015 K/s) on Al, Pb and GaAs. These observations are captured by the Θ -β-Q systematics. Homogeneous nucleation is inherent in molecular dynamics simulations of perfect bulk crystals with typical heating rates Q (~ 1012-1013 K/s) similar to those in shock wave loading and intense laser irradiation. Single-phase and two-phase simulations of melting of fcc metals (Al, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au), a bcc metal (Ta), oxides (MgO and SiO2) with various types of force field (FF) such as embedded atom method potential, first-principle potential and Morse-stretch charge equilibrium FF etc., have demonstrated superheating consistent with the superheating systematics. Despite of the large range of melting temperatures observed, the extrapolation of melting curves from diamond-anvil-cell experiments on V, Mo, Ta and W remain discrepant with shock wave results even when superheating and experiment uncertainties are taken into account. In the case of Fe, the discrepancy is less pronounced. This may result from a not yet explored solid-solid phase transition.

  12. Sub-micrometer dropwise condensation under superheated and rarefied vapor condition.

    PubMed

    Anand, Sushant; Son, Sang Young

    2010-11-16

    Phase change accompanying conversion of a saturated or superheated vapor in the presence of subcooled surfaces is one of the most common occurring phenomena in nature. The mode of phase change that follows such a transformation is dependent upon surface properties such as contact angle and thermodynamic conditions of the system. In present studies, an experimental approach is used to study the physics behind droplet growth on a partially wet surface. Superheated vapor at low pressures of 4-5 Torr was condensed on subcooled silicon surface with a static contact angle of 60° in the absence of noncondensable gases, and the condensation process was monitored using environmental scanning electron microscopy (ESEM) with sub-microscopic spatial resolution. The condensation process was analyzed in the form of size growth of isolated droplets before a coalescence event ended the regime of single droplet growth. Droplet growth obtained as a function of time reveals that the rate of growth decreases as the droplet increases in size. This behavior is indicative of an overall droplet growth law existing over larger time scales for which the current observations in their brief time intervals could be fitted. A theoretical model based on kinetic theory further support the experimental observations indicating a mechanism where growth occurs by interfacial mass transport directly on condensing droplet surface. Evidence was also found that establishes the presence of sub-microscopic droplets nucleating and growing between microscopic droplets for the partially wetting case.

  13. Superheated liquid and supercritical denatured ethanol extraction of antioxidants from Crimson red grape stems.

    PubMed

    Wenzel, Jonathan; Samaniego, Cheryl Storer; Wang, Lihua; Nelson, La'Shyla; Ketchum, Korrine; Ammerman, Michelle; Zand, Ali

    2015-11-01

    Grapes are widely known for health benefits due to their antioxidant content. In wine production, grape stems are often discarded, though they has a higher content of antioxidants than the juice. The effectiveness of using an environmentally friendly solvent, ethanol, as a superheated liquid and supercritical fluid to extract antioxidant compounds from grape stems of organically grown Crimson Seedless grapes was evaluated. The Ferric Reducing Ability of Plasma (FRAP) assay and the Total Phenolic Content (TPC), or Folin-Ciocalteu assay, were used to quantify the antioxidant power of grape stem extracts. The extractions were performed at temperatures between 160°C and 300°C at constant density. It was found that the optimal extraction temperature was 204°C, at superheated liquid conditions, with a FRAP value of 0.670 mmol Trolox Equivalent/g of dry grape stem. The FRAP values were higher than other studies that extracted antioxidants from grape stems using single-pass batch extraction. PMID:26788298

  14. Rapid Online Non-Enzymatic Protein Digestion Analysis with High Pressure Superheated ESI-MS

    NASA Astrophysics Data System (ADS)

    Chen, Lee Chuin; Kinoshita, Masato; Noda, Masato; Ninomiya, Satoshi; Hiraoka, Kenzo

    2015-07-01

    Recently, we reported a new ESI ion source that could electrospray the super-heated aqueous solution with liquid temperature much higher than the normal boiling point ( J. Am. Soc. Mass Spectrom. 25, 1862-1869). The boiling of liquid was prevented by pressurizing the ion source to a pressure greater than atmospheric pressure. The maximum operating pressure in our previous prototype was 11 atm, and the highest achievable temperature was 180°C. In this paper, a more compact prototype that can operate up to 27 atm and 250°C liquid temperatures is constructed, and reproducible MS acquisition can be extended to electrospray temperatures that have never before been tested. Here, we apply this super-heated ESI source to the rapid online protein digestion MS. The sample solution is rapidly heated when flowing through a heated ESI capillary, and the digestion products are ionized by ESI in situ when the solution emerges from the tip of the heated capillary. With weak acid such as formic acid as solution, the thermally accelerated digestion (acid hydrolysis) has the selective cleavage at the aspartate (Asp, D) residue sites. The residence time of liquid within the active heating region is about 20 s. The online operation eliminates the need to transfer the sample from the digestion reactor, and the output of the digestive reaction can be monitored and manipulated by the solution flow rate and heater temperature in a near real-time basis.

  15. Development of a new pressure dependent threshold superheated drop detector for neutrons

    NASA Astrophysics Data System (ADS)

    Rezaeian, Peiman; Raisali, Gholamreza; Akhavan, Azam; Ghods, Hossein; Hajizadeh, Bardia

    2015-03-01

    In this paper, a set of superheated drop detectors operated at different pressures is developed and fabricated by adding an appropriate amount of Freon-12 liquid on the free surface of the detector. The fabricated detectors have been used for determination of the threshold pressure for 2.89 MeV neutrons of a neutron generator in order to estimate the thermodynamic efficiency. Finally, knowing the thermodynamic efficiency of the detector and in a similar manner, the threshold pressure for 241Am-Be neutrons is determined and accordingly, the maximum neutron energy of the source spectrum is estimated. The maximum neutron energy of the 241Am-Be is estimated as 10.97±2.11 MeV. The agreement between this measured maximum energy and the reported value of the 241Am-Be neutron source shows that the method developed to apply pressure on the superheated drop detectors can be used to control the energy threshold of these detectors.

  16. Size Dependence of the Drying Characteristics of Single Lignite Particles in Superheated Steam

    NASA Astrophysics Data System (ADS)

    Kiriyama, Tsuyoshi; Sasaki, Hideaki; Hashimoto, Akira; Kaneko, Shozo; Maeda, Masafumi

    2014-12-01

    Loy Yang lignite particles 10, 5, and 2.5 mm in diameter were dried with superheated steam at temperatures ranging from 383 K to 443 K (110 °C to 170 °C) under atmospheric pressure. The drying rates were obtained by measuring their weights with an electronic balance, while temperatures of the particles were monitored. The following typical drying characteristics were observed: (i) Temperature of lignite rose to 373 K (100 °C) accompanied by condensation of steam on the surface. (ii) A constant drying rate period was then observed, while temperature of the overall particle was maintained at 373 K (100 °C). (iii) A decreasing drying rate period began accompanied by a rise in surface temperature, and eventually the overall particle reached the temperature of the superheated steam. Based on these results, the evaporation rate of water was expressed as a function of particle diameter. A numerical model for simulating the drying process of lignite, which was developed for a large particle in a previous study, was modified to make it applicable to small particles. The model is applicable for simulations of drying behaviors of lignite with size distribution in various dryers when an appropriate heat transfer coefficient is given.

  17. Rapid Online Non-Enzymatic Protein Digestion Analysis with High Pressure Superheated ESI-MS.

    PubMed

    Chen, Lee Chuin; Kinoshita, Masato; Noda, Masato; Ninomiya, Satoshi; Hiraoka, Kenzo

    2015-07-01

    Recently, we reported a new ESI ion source that could electrospray the super-heated aqueous solution with liquid temperature much higher than the normal boiling point (J. Am. Soc. Mass Spectrom. 25, 1862-1869). The boiling of liquid was prevented by pressurizing the ion source to a pressure greater than atmospheric pressure. The maximum operating pressure in our previous prototype was 11 atm, and the highest achievable temperature was 180°C. In this paper, a more compact prototype that can operate up to 27 atm and 250°C liquid temperatures is constructed, and reproducible MS acquisition can be extended to electrospray temperatures that have never before been tested. Here, we apply this super-heated ESI source to the rapid online protein digestion MS. The sample solution is rapidly heated when flowing through a heated ESI capillary, and the digestion products are ionized by ESI in situ when the solution emerges from the tip of the heated capillary. With weak acid such as formic acid as solution, the thermally accelerated digestion (acid hydrolysis) has the selective cleavage at the aspartate (Asp, D) residue sites. The residence time of liquid within the active heating region is about 20 s. The online operation eliminates the need to transfer the sample from the digestion reactor, and the output of the digestive reaction can be monitored and manipulated by the solution flow rate and heater temperature in a near real-time basis.

  18. Cs2 ‘diffuse bands’ emission from superheated cesium vapor

    NASA Astrophysics Data System (ADS)

    Pichler, G.; Makdisi, Y.; Kokaj, J.; Thomas, N.; Mathew, J.; Beuc, R.

    2016-07-01

    Thermal emission from superheated cesium vapor was studied to very high temperatures from 700 °C to 1000 °C. This was performed in the vapor condition only and with no liquid cesium present in the all-sapphire cell. We observed a number of atomic and molecular spectral features simultaneously in emission and absorption, especially peculiar thermal emission of cesium dimer diffuse bands (2 3Πg → a 3∑u + transitions) around 710 nm coexisting with absorption bands around first resonance lines at 852 and 894 nm. We performed appropriate calculations of the diffuse band emission profiles and compared them with measured profiles. We also performed absorption measurements and compared observed diffuse band profiles with calculated ones. Possible applications of the observed phenomena will be discussed in terms of the solar energy conversion using dense cesium vapor.

  19. Evaluation of Drying Rates of Lignite Particles in Superheated Steam Using Single-Particle Model

    NASA Astrophysics Data System (ADS)

    Kiriyama, Tsuyoshi; Sasaki, Hideaki; Hashimoto, Akira; Kaneko, Shozo; Maeda, Masafumi

    2016-08-01

    Drying rates of lignite particle groups in superheated steam are evaluated using a single-particle model developed for Australian lignite. Size distributions of the particles are assumed to obey the Rosin-Rammler equation with the maximum particle diameters defined as 100, 50, and 6 mm. The results show the drying rate of a lignite group depends strongly on the maximum particle size, and removal of large particles prior to drying is shown to be effective to reduce the drying time. The calculation model is available for simulations of drying behaviors of lignite in various dryers when an appropriate heat transfer coefficient is given. This study simulates the drying of particles smaller than 6 mm using a heat transfer coefficient in a fluidized bed dryer reported elsewhere. The required drying time estimated from the calculation is comparable to the processing time reported in an actual fluidized bed dryer, supporting the validity of the calculation model.

  20. Effectiveness of superheated steam and gas catalytic infrared heat treatments to inactivate Salmonella on raw almonds.

    PubMed

    Bari, Latiful; Nei, Daisuke; Sotome, Itaru; Nishina, Ikuo Y; Hayakawa, Fumiyo; Isobe, Seiichi; Kawamoto, Shinnichi

    2010-07-01

    The majority of the almond-related outbreaks have been associated with Salmonella. Therefore, it is necessary to find an effective method to inactivate these organisms on the raw almond before distribution in the market. This study was conducted to assess the effectiveness of superheated steam (SHS) treatments followed by catalytic infrared (IR) heat treatment to inactivate Salmonella populations on raw almond and to determine the effect of these treatments on the quality of raw almond. It has been found that SHS treatment for 70 seconds followed by catalytic IR heat treatment for 70 seconds was able to reduce 5.73 +/- 0.11 log CFU/g Salmonella population, and no survivors were found in the enrichment medium. The overall visual quality parameters of both treated and nontreated almonds were found within the acceptable limit. Therefore, SHS treatments for 70 seconds followed by catalytic IR heat treatment for 70 seconds could be an effective decontamination method for raw almonds.

  1. Neutron field parameter measurements on the JET tokamak by means of super-heated fluid detectors

    SciTech Connect

    Gherendi, M.; Craciunescu, T.; Pantea, A.; Zoita, V. L.; Johnson, M. Gatu; Hellesen, C.; Conroy, S.; Baltog, I.; Edlington, T.; Kiptily, V.; Popovichev, S.; Murari, A.; Collaboration: JET EFDA Contributors

    2012-10-15

    The neutron field parameters (fluence and energy distribution) at a specific location outside the JET Torus Hall have been measured by means of super-heated fluid detectors (or 'bubble detectors') in combination with an independent, time-of-flight, technique. The bubble detector assemblies were placed at the end of a vertical line of sight at about 16 m from the tokamak mid plane. Spatial distributions of the neutron fluence along the radial and toroidal directions have been obtained using two-dimensional arrays of bubble detectors. Using a set of three bubble detector spectrometers the neutron energy distribution was determined over a broad energy range, from about 10 keV to above 10 MeV, with an energy resolution of about 30% at 2.5 MeV. The very broad energy response allowed for the identification of energy features far from the main fusion component (around 2.45 MeV for deuterium discharges).

  2. Explosive boiling of a metallic glass superheated by nanosecond pulse laser ablation

    SciTech Connect

    Jiang, M. Q. E-mail: lhdai@lnm.imech.ac.cn; Wei, Y. P.; Wilde, G.; Dai, L. H. E-mail: lhdai@lnm.imech.ac.cn

    2015-01-12

    We report an explosive boiling in a Zr-based (Vitreloy 1) bulk metallic glass irradiated by a nanosecond pulse laser with a single shot. This critical phenomenon is accompanied by the ejection of high-temperature matter from the target and the formation of a liquid-gas spinodal pattern on the irradiated area. An analytical model reveals that the glassy target experiences the normal heating (melting) and significant superheating, eventually culminating in explosive boiling near the spinodal limit. Furthermore, the time lag of nucleation and the critical radius of vapor bubbles are theoretically predicted, which are in agreement with the experimental observations. This study provides the investigation on the instability of a metallic glass liquid near the thermodynamic critical temperature.

  3. An active drop counting device using condenser microphone for superheated emulsion detector

    SciTech Connect

    Das, Mala; Marick, C.; Kanjilal, D.; Saha, S.

    2008-11-15

    An active device for superheated emulsion detector is described. A capacitive diaphragm sensor or condenser microphone is used to convert the acoustic pulse of drop nucleation to electrical signal. An active peak detector is included in the circuit to avoid multiple triggering of the counter. The counts are finally recorded by a microprocessor based data acquisition system. Genuine triggers, missed by the sensor, were studied using a simulated clock pulse. The neutron energy spectrum of {sup 252}Cf fission neutron source was measured using the device with R114 as the sensitive liquid and compared with the calculated fission neutron energy spectrum of {sup 252}Cf. Frequency analysis of the detected signals was also carried out.

  4. Antifreeze protein-induced superheating of ice inside Antarctic notothenioid fishes inhibits melting during summer warming.

    PubMed

    Cziko, Paul A; DeVries, Arthur L; Evans, Clive W; Cheng, Chi-Hing Christina

    2014-10-01

    Antifreeze proteins (AFPs) of polar marine teleost fishes are widely recognized as an evolutionary innovation of vast adaptive value in that, by adsorbing to and inhibiting the growth of internalized environmental ice crystals, they prevent death by inoculative freezing. Paradoxically, systemic accumulation of AFP-stabilized ice could also be lethal. Whether or how fishes eliminate internal ice is unknown. To investigate if ice inside high-latitude Antarctic notothenioid fishes could melt seasonally, we measured its melting point and obtained a decadal temperature record from a shallow benthic fish habitat in McMurdo Sound, Antarctica. We found that AFP-stabilized ice resists melting at temperatures above the expected equilibrium freezing/melting point (eqFMP), both in vitro and in vivo. Superheated ice was directly observed in notothenioid serum samples and in solutions of purified AFPs, and ice was found to persist inside live fishes at temperatures more than 1 °C above their eqFMP for at least 24 h, and at a lower temperature for at least several days. Field experiments confirmed that superheated ice occurs naturally inside wild fishes. Over the long-term record (1999-2012), seawater temperature surpassed the fish eqFMP in most summers, but never exceeded the highest temperature at which ice persisted inside experimental fishes. Thus, because of the effects of AFP-induced melting inhibition, summer warming may not reliably eliminate internal ice. Our results expose a potentially antagonistic pleiotropic effect of AFPs: beneficial freezing avoidance is accompanied by melting inhibition that may contribute to lifelong accumulation of detrimental internal ice crystals.

  5. Isothermal compressibility maxima of hydrogen fluoride in the supercritical and superheated vapor regions.

    PubMed

    Baburao, Barath; Visco, Donald P

    2006-12-28

    The highly nonideal behavior of hydrogen fluoride (HF) vapor has been considered to be the origin of its numerous vapor phase anomalies. In this work, we report one such potential vapor phase anomaly for HF. For a nonassociating substance like propane, the response functions go through a maximum only once in the supercritical region. However, for HF, when an association model is used to predict the isothermal compressibility (KT), it exhibits a maximum in the supercritical region more than once, and this peak extends well in to the superheated vapor region upon decompression. This theoretical prediction is also supported by two other models recently developed for HF. Note that experimental values of KT for HF have not been reported in the literature so far. Preliminary investigations on this KT maximum for HF have suggested no reentrant spinodal, singularity-free scenario, or any additional first-order phase transition, unlike water, and, also, no lambda (or higher-order phase) transitions, unlike liquid helium. However, this KT peak is similar to the experimentally supported heat capacity (CP) peak of HF which extends into the supercritical and superheated vapor regions. Similar to the CP peak, which is understood based on vapor-phase clustering in HF, we relate KT to the derivatives of enthalpy and entropy of the system. Also, we analyze some of the P-v-T experimental data that are available to provide an overview of the KT behavior in the region of interest, and compare them with the model results. Finally, to explore the effect of including a distribution pattern for the oligomers, we report the results on a model that only includes association. Using this approach, we report KT results with and without a Poisson-type oligomer distribution and show that the KT appears once this distribution scheme is specified. PMID:17181277

  6. Energy- and angle-differential neutron fluence measurements with superheated drop (bubble) detectors

    NASA Astrophysics Data System (ADS)

    d'Errico, Francesco; Matzke, Manfred; Siebert, Bernd R. L.

    2002-01-01

    One of the latest additions to the field of neutron spectrometry is based on the active control of the response functions of superheated emulsions. By varying the superheat of the detectors, either changing their operating temperature or applied pressure, it is possible to generate a matrix consisting of nested responses suitable for few-channel energy spectrometry. In the device presented here, a detector is embedded in a recess milled on the surface of a moderating sphere. This sphere has the purpose of introducing an angular dependence in the otherwise nearly isotropic response of the detector. The device relies on the acoustical detection of bubbles and on temperature stepping to vary the superheated emulsion thresholds. In correspondence to each temperature/threshold, measurements are sequentially performed at different angular orientations of the sphere. The response matrix of the system to monoenergetic neutrons was determined as a function of angular position by means of Monte Carlo neutron transport simulations. The directional spectrometer was tested by means of irradiations with a californium neutron source. Energy- and angle-differential unfolding of the detector readings was performed by means of a maximum-entropy technique which does not require a-priori information. The spectrometer operates well with large energy-angle groups, and produces accurate integral values of total fluence, which can be used to derive quantities such as ambient dose equivalent H*(10) or directional dose equivalent H'(10). However, the device presents limitations in unfolding spectra over a finer group structure, and will require the future developments outlined in the conclusions.

  7. Antifreeze protein-induced superheating of ice inside Antarctic notothenioid fishes inhibits melting during summer warming

    PubMed Central

    Cziko, Paul A.; DeVries, Arthur L.; Evans, Clive W.; Cheng, Chi-Hing Christina

    2014-01-01

    Antifreeze proteins (AFPs) of polar marine teleost fishes are widely recognized as an evolutionary innovation of vast adaptive value in that, by adsorbing to and inhibiting the growth of internalized environmental ice crystals, they prevent death by inoculative freezing. Paradoxically, systemic accumulation of AFP-stabilized ice could also be lethal. Whether or how fishes eliminate internal ice is unknown. To investigate if ice inside high-latitude Antarctic notothenioid fishes could melt seasonally, we measured its melting point and obtained a decadal temperature record from a shallow benthic fish habitat in McMurdo Sound, Antarctica. We found that AFP-stabilized ice resists melting at temperatures above the expected equilibrium freezing/melting point (eqFMP), both in vitro and in vivo. Superheated ice was directly observed in notothenioid serum samples and in solutions of purified AFPs, and ice was found to persist inside live fishes at temperatures more than 1 °C above their eqFMP for at least 24 h, and at a lower temperature for at least several days. Field experiments confirmed that superheated ice occurs naturally inside wild fishes. Over the long-term record (1999–2012), seawater temperature surpassed the fish eqFMP in most summers, but never exceeded the highest temperature at which ice persisted inside experimental fishes. Thus, because of the effects of AFP-induced melting inhibition, summer warming may not reliably eliminate internal ice. Our results expose a potentially antagonistic pleiotropic effect of AFPs: beneficial freezing avoidance is accompanied by melting inhibition that may contribute to lifelong accumulation of detrimental internal ice crystals. PMID:25246548

  8. Optimal operation of a concurrent-flow corn dryer with a drying heat pump using superheated steam

    SciTech Connect

    Moraitis, C.S.; Akritidis, C.B.

    1998-07-01

    A numerical model of a concurrent-flow dryer of corn using superheated steam as drying medium is solved applying a shooting technique, so as to satisfy boundary conditions imposed by the optimal design of a drying heat pump. The drying heat pump is based on the theory of minimum energy cycles. The solution of the model proves the applicability of the heat pump to a concurrent-flow dryer, achieving a Specific Energy Consumption as low as 1080 kJ/kg.

  9. Effective and reusable monolith capillary trap of nitrosamine extraction by superheated water from frankfurter sausage.

    PubMed

    Chienthavorn, Orapin; Ramnut, Narumol; Subprasert, Panee; Sasook, Anupop; Insuan, Wimonrut

    2014-02-12

    A novel, simple, rapid, and inexpensive method of extraction and cleanup of nitrosamines from frankfurter sausage was achieved with a capillary filled with monolith of either polystyrene-co-divinylbenzene (PS-DVB), Polydivinylbenzene (P-DVB), or silica that had been fabricated. The study of capability in trapping nonpolar matrix and monolith capillaries with varied lengths revealed that a silica monolith gave the best result for nitrosamine determination. With an online coupling between superheated water extraction (SWE) and silica monolith capillary connected to a 5% phenyl-methylpolysiloxane column, factors affecting the extraction and determination, namely, sensitivity with and without the monolith, reusability, injection-injection repeatability, capillary-capillary precision, and chromatographic separation, were investigated. This confirmed the feasibility of the method. The optimal length of silica monolith capillary was 30 mm, offering reuse more than 20 times. Separation and quantification of selected volatile nitrosamines were carried out using gas chromatography (GC) coupled with either a flame ionization detector (FID) or mass spectrometer (MS). The overall extraction and determination method determined by GC-MS allowed for a recovery of 75-88% with a <5% relative standard deviation (RSD) and detection limit of 2-5 ng of injected nitrosamine.

  10. Modification of oil palm mesocarp fiber characteristics using superheated steam treatment.

    PubMed

    Nordin, Noor Ida Amalina Ahamad; Ariffin, Hidayah; Andou, Yoshito; Hassan, Mohd Ali; Shirai, Yoshihito; Nishida, Haruo; Yunus, Wan Zin Wan; Karuppuchamy, Subbian; Ibrahim, Nor Azowa

    2013-07-30

    In this study, oil palm mesocarp fiber (OPMF) was treated with superheated steam (SHS) in order to modify its characteristics for biocomposite applications. Treatment was conducted at temperatures 190-230 °C for 1, 2 and 3 h. SHS-treated OPMF was evaluated for its chemical composition, thermal stability, morphology and crystallinity. OPMF treated at 230 °C exhibited lower hemicellulose content (9%) compared to the untreated OPMF (33%). Improved thermal stability of OPMF was found after the SHS treatment. Moreover, SEM and ICP analyses of SHS-treated OPMF showed that silica bodies were removed from OPMF after the SHS treatment. XRD results exhibited that OPMF crystallinity increased after SHS treatment, indicating tougher fiber properties. Hemicellulose removal makes the fiber surface more hydrophobic, whereby silica removal increases the surface roughness of the fiber. Overall, the results obtained herewith suggested that SHS is an effective treatment method for surface modification and subsequently improving the characteristics of the natural fiber. Most importantly, the use of novel, eco-friendly SHS may contribute to the green and sustainable treatment for surface modification of natural fiber.

  11. The Parr formula for the superheating field in a semi-infinite film

    NASA Astrophysics Data System (ADS)

    Del Castillo, Pierre

    2005-05-01

    Di Bartolo, Dolgert, and Dorsey [Phys. Rev. B 53, 5650-5660 (1996)] have constructed asymptotic matched solutions at order 2 for the half-space Ginzburg-Landau model in the weak-κ limit. These authors deduced a formal expansion for the superheating field hsh(κ) up to order 4, extending the de Gennes formula [Proceedings of the Eighth Latin American School of Physics, Caracas, 1966] and the two terms in Parr's formula [Z. Phys. B 25, 359-361 (1976)]. On the other hand, the present author [Eur. J. Appl. Math 13, 519-547 (2002)] obtained two terms in the lower bound for hsh(κ). In this paper, we prove rigorously that the second term of the expansion of hsh(κ) is of the order of O(κ1/2) and we get the Parr formula. We improve the upper bound obtained by Bolley and Helffer [Ann. Inst. Henri Poincaré, Anal. Non Linéaire 14, 597-613 (1997)] and we get κ(hsh(κ))2⩽2-3/2=15/32κ+O(κ1+ρ), ρ >0. The proof is based on new estimates for f', A, and A'. To achieve this, we are guided by the analysis of the properties of the approximate solution constructed previously in [Del Castillo, Math Modell. Numer. Anal. 36, 971-973 (2002); J. Math. Phys. 44, 2416-2450 (2003); Dolgert et al., Phys. Rev. B 53, 5650-5660 (1996)].

  12. A two-phase model for subcooled and superheated liquid jets

    SciTech Connect

    Muralidhar, R.; Jersey, G.R.; Krambeck, F.J.; Sundaresan, S.

    1995-12-31

    This paper describes a two-phase jet model for predicting the liquid rainout (capture) and composition of subcooled and superheated HF/additive pressurized liquid releases. The parent droplets of the release mixture constitute the fist phase. The second phase can in general be a vapor-liquid fog. The drops are not in equilibrium with the fog phase with which they exchange mass and energy. The fog at any location is assumed to be in local equilibrium. Correlations are developed for predicting the initial drop size for hydrodynamic breakup of jets. Applications are discussed in this paper for HF/additive mixtures. The fog phase calculations account for HF oligomerization and HF-water complex formation in the vapor phase and equilibrium between the liquid and vapor in the fog. The model incorporates jet trajectory calculations and hence can predict the amount of liquid rained out (liquid capture) and the capture distance. The HF captures predicted by the model for various release conditions are in agreement with small and large scale release experiments.

  13. Speciation and chemical activities in superheated sodium borate solutions. Final report

    SciTech Connect

    Weres, O.

    1993-06-01

    The system H{sub 2}O-B{sub 2}O{sub 3}-Na{sub 2}O has been studied experimentally at 277{degrees} and 317{degrees}C. The activities of water and boric acid have been determined at mole ratios Na/B from 0 to 1.5, and total dissolved solids 3 to 80 weight percent. The activity of boric acid has been fitted to within experimental error using a speciation model with eight complex species. This model is consistent with the model previously published by Mesmer et al. The electrolyte properties of the liquid are modelled using the Pitzer-Simonson Model of very concentrated electrolyte solutions. The calculated values of water activity agree with experiment, and the activity of NaOH and pOH have also been calculated. These data will allow prediction of the composition and chemical behavior of sodium borate liquids that may accumulate in the superheated crevices within a steam generator. A modified form of the model is provided for use with MULTEQ. The potassium borate system also was briefly studied at 317{degrees}C, and is adequately described by a model with five complex species. The potassium borate liquid is more alkaline at K/B = 1 than a sodium borate liquid at the same mole ratio, but pOH in the two systems is the same at lower mole ratios.

  14. Separation of parabens on a zirconia-based stationary phase in superheated water chromatography.

    PubMed

    Yarita, Takashi; Aoyagi, Yoshie; Sasai, Haruka; Nishigaki, Atsuko; Shibukawa, Masami

    2013-01-01

    A superheated water chromatography (SWC) method for the separation of alkyl esters of 4-hydroxybenzoic acid (parabens) using a zirconia-based stationary phase was developed and applied to real sample analysis. First, the SWC system was optimized in terms of the proper length of the preheating coil for establishing thermal equilibration of the mobile phase entering the column at the oven temperature. Next, the effect of the column temperature on the retention was investigated at 100-180°C. The elution time for all parabens decreased with increasing column temperature, and linear relationships between ln k and 1/T were obtained. At higher column temperatures, the elution time was further shortened because of the increased mobile-phase flow rate. Nevertheless, the loss of column efficiency at the higher flow rates was not significant. The application of the present method to the analysis of commercial lotions was then demonstrated. The quantification results obtained from SWC showed good agreement with those from a conventional HPLC method.

  15. Numerical and experimental study of the dynamics of a superheated jet

    NASA Astrophysics Data System (ADS)

    Sinha, Avick; Gopalakrishnan, Shivasubramanian; Balasubramanian, Sridhar

    2015-11-01

    Flash-boiling is a phenomenon where a liquid experiences low pressures in a system resulting in it getting superheated. The sudden drop in pressures results in accelerated expansion and violent vapour formation. Understanding the physics behind the jet disintegration and flash-boiling phenomenon is still an open problem, with applications in automotive and aerospace combustors. The behaviour of a flash-boiling jet is highly dependent on the input parameters, inlet temperature and pressure. In the present study, the external (outside nozzle) and the internal (inside nozzle) flow characteristics of the two-phase flow has been studied numerically and experimentally. The phase change from liquid to vapour takes place over a finite period of time, modeled sing Homogeneous Relaxation Model (HRM). In order to validate the numerical results, controlled experiments were performed. Optical diagnostic techniques such as Particle Image Velocimetry (PIV) and Shadowgraphy were used to study the flow characteristics. Spray angle, penetration depth, droplet spectra were obtained which provides a better understanding of the break-up mechanism. Linear stability analysis is performed to study the stability characteristics of the jet.

  16. [Suitability of Bacillus subtilis and Bacillus stearothermophilus spores as test organism bioindicators for detecting superheating of steam].

    PubMed

    Spicher, G; Peters, J

    1997-02-01

    Biological indicators used to test sterilisation procedures for their efficacy consist of a so-called germ carrier to which the microorganisms used as test organisms adhere. In previous papers we demonstrated that carriers made of filter paper on contact with saturated steam show superheating while carriers made of glass fibre fleece as well as wetted filter paper do not. Using spores of Bacillus subtilis and Bacillus stearothermophilus as test organisms we have now investigated whether and to what extent carrier superheating affects the characteristic values (t50%) of these biological indicators. The indicators were exposed to saturated steam at 100 degrees C (B. subtilis) or 120 degrees C (B. stearothermophilus) under three different exposure conditions: 1. dry (i.e. conditioned to 45% relative humidity before introduction into the sterilising chamber), freely accessible; 2. dry with a substratum and a cover of filter card-board; 3. wet (moistened with twice distilled water before introduction into the sterilising chamber), freely accessible. For previously selected exposure periods, the incidence of indicators with surviving test organisms was determined. The reaction pattern of bioindicators with spores of B. stearothermophilus was different from that of bioindicators with spores of B. subtilis. For B. subtilis, the incidence of bioindicators exhibiting surviving test organisms depended on the nature of the carries as well as on the exposure conditions. On filter paper carriers, t50% increased in the order "wet, freely accessible", "dry, freely accessible", "dry, between filter card-board". On dry and wetted glass fibre fleece, resistance was approximately the same; when the indicators were sandwiched between layers of filter card-board, t50% increased. For B. stearothermophilus, t50% was largely dependent on the carrier material alone. The values obtained for filter paper were invariably much lower than those for glass fibre fleece. As the results show, using

  17. Superheating and supercooling of Ge nanocrystals embedded inSiO2

    SciTech Connect

    Xu, Q.; Sharp, I.D.; Yuan, C.W.; Yi, D.O.; Liao, C.Y.; Glaeser,A.M.; Minor, A.M.; Beeman, J.W.; Ridgway, M.C.; Kluth, P.; Ager III,J.W.; Chrzan, D.C.; Haller, E.E.

    2006-08-21

    Free-standing nanocrystals exhibit a size-dependant thermodynamic melting point reduction relative to the bulk melting point that is governed by the surface free energy. The presence of an encapsulating matrix, however, alters the interface free energy of nanocrystals and their thermodynamic melting point can either increase or decrease relative to bulk. Furthermore, kinetic contributions can significantly alter the melting behaviors of embedded nanoscale materials. To study the effect of an encapsulating matrix on the melting behavior of nanocrystals, we performed in situ electron diffraction measurements on Ge nanocrystals embedded in a silicon dioxide matrix. Ge nanocrystals were formed by multi-energy ion implantation into a 500 nm thick silica thin film on a silicon substrate followed by thermal annealing at 900 C for 1 h. We present results demonstrating that Ge nanocrystals embedded in SiO{sub 2} exhibit a 470 K melting/solidification hysteresis that is approximately symmetric about the bulk melting point. This unique behavior, which is thought to be impossible for bulk materials, is well described using a classical thermodynamic model that predicts both kinetic supercooling and kinetic superheating. The presence of the silica matrix suppresses surface pre-melting of nanocrystals. Therefore, heterogeneous nucleation of both the liquid phase and the solid phase are required during the heating and cooling cycle. The magnitude of melting hysteresis is governed primarily by the value of the liquid Ge/solid Ge interface free energy, whereas the relative values of the solid Ge/matrix and liquid Ge/matrix interface free energies govern the position of the hysteresis loop in absolute temperature.

  18. Optical-cell evidence for superheated ice under gas-hydrate-forming conditions

    USGS Publications Warehouse

    Stern, L.A.; Hogenboom, D.L.; Durham, W.B.; Kirby, S.H.; Chou, I.-Ming

    1998-01-01

    We previously reported indirect but compelling evidence that fine-grained H2O ice under elevated CH4 gas pressure can persist to temperatures well above its ordinary melting point while slowly reacting to form methane clathrate hydrate. This phenomenon has now been visually verified by duplicating these experiments in an optical cell while observing the very slow hydrate-forming process as the reactants were warmed from 250 to 290 K at methane pressures of 23 to 30 MPa. Limited hydrate growth occurred rapidly after initial exposure of the methane gas to the ice grains at temperatures well within the ice subsolidus region. No evidence for continued growth of the hydrate phase was observed until samples were warmed above the equilibrium H2O melting curve. With continued heating, no bulk melting of the ice grains or free liquid water was detected anywhere within the optical cell until hydrate dissociation conditions were reached (292 K at 30 MPa), even though full conversion of the ice grains to hydrate requires 6-8 h at temperatures approaching 290 K. In a separate experimental sequence, unreacted portions of H2O ice grains that had persisted to temperatures above their ordinary melting point were successfully induced to melt, without dissociating the coexisting hydrate in the sample tube, by reducing the pressure overstep of the equilibrium phase boundary and thereby reducing the rate of hydrate growth at the ice-hydrate interface. Results from similar tests using CO2 as the hydrate-forming species demonstrated that this superheating effect is not unique to the CH4-H2O system.

  19. Investigations of structural transformation within metal (austenite chromium-manganese steel) at the external surface of steam superheating tubes

    NASA Astrophysics Data System (ADS)

    Bogachev, V. A.; Pshechenkova, T. P.; Shumovskaya, M. A.

    2016-04-01

    The elemental composition of an altered layer at the external surface of a steam superheating tube of grade DI59 steel is investigated after long-term operation. It is shown that the layer is located between a scale and a matrix and depleted by silicon, manganese, copper, and chromium with the maximum oxidizer affinity, enriched by iron and nickel to 90%, and mainly composed of the α-Fe phase (ferrite) with the ferromagnetic properties. The layer formed as a result of selective oxidation and diffusion from the matrix into the metal scale with the less standard free energy of the formation of sulfides and oxides. A magnetic ferrite meter is used in the experimental investigation of the layer evolution by testing grade DI59 steel for heat resistance in air environment at temperatures of 585, 650, and 700°C for 15 × 103 h; creep at a temperature of 750°C and a stress of 60 MPa; and long-term strength at temperatures of 700 and 750°C and stresses of from 30 to 80 MPa. Specimens for tests are made of tubes under as-received conditions. The relationship between the ferrite phase content in the surface metal layer and the temperature and time of test is determined. The dependence is developed to evaluate the equivalent temperature for operation of the external surface of steam superheating tubes using data of magnetic ferritometry. It is shown that operation temperatures that are determined by the ferrite phase content and the σ phase concentration in the metal structure of steam superheating tubes with the significant operating time are close. It is proposed to use magnetic ferritometry for revelation of thermal nonuniformity and worst tubes of steam superheaters of HPP boilers.

  20. Application of the BINS superheated drop detector spectrometer to the {sup 9}Be(p,xn) neutron energy spectrum determination

    SciTech Connect

    Di Fulvio, A.; Ciolini, R.; Mirzajani, N.; Romei, C.; D'Errico, F.; Bedogni, R.; Esposito, J.; Zafiropoulos, D.; Colautti, P.

    2013-07-18

    In the framework of TRASCO-BNCT project, a Bubble Interactive Neutron Spectrometer (BINS) device was applied to the characterization of the angle-and energy-differential neutron spectra generated by the {sup 9}Be(p,xn)reaction. The BINS spectrometer uses two superheated emulsion detectors, sequentially operated at different temperatures and thus provides a series of six sharp threshold responses, covering the 0.1-10 MeV neutron energy range. Spectrum unfolding of the data was performed by means of MAXED code. The obtained angle, energy-differential spectra were compared with those measured with a Bonner sphere spectrometer, a silicon telescope spectrometer and literature data.

  1. Application of the BINS superheated drop detector spectrometer to the 9Be(p,xn) neutron energy spectrum determination

    NASA Astrophysics Data System (ADS)

    Di Fulvio, A.; Ciolini, R.; Mirzajani, N.; Romei, C.; d'Errico, F.; Bedogni, R.; Esposito, J.; Zafiropoulos, D.; Colautti, P.

    2013-07-01

    In the framework of TRASCO-BNCT project, a Bubble Interactive Neutron Spectrometer (BINS) device was applied to the characterization of the angle-and energy-differential neutron spectra generated by the 9Be(p,xn)reaction. The BINS spectrometer uses two superheated emulsion detectors, sequentially operated at different temperatures and thus provides a series of six sharp threshold responses, covering the 0.1-10 MeV neutron energy range. Spectrum unfolding of the data was performed by means of MAXED code. The obtained angle, energy-differential spectra were compared with those measured with a Bonner sphere spectrometer, a silicon telescope spectrometer and literature data.

  2. Peculiarities of methane clathrate hydrate formation and solid-state deformation, including possible superheating of water ice

    USGS Publications Warehouse

    Stern, L.A.; Kirby, S.H.; Durham, W.B.

    1996-01-01

    Slow, constant-volume heating of water ice plus methane gas mixtures forms methane clathrate hydrate by a progressive reaction that occurs at the nascent ice/liquid water interface. As this reaction proceeds, the rate of melting of metastable water ice may be suppressed to allow short-lived superheating of ice to at least 276 kelvin. Plastic flow properties measured on clathrate test specimens are significantly different from those of water ice; under nonhydrostatic stress, methane clathrate undergoes extensive strain hardening and a process of solid-state disproportionation or exsolution at conditions well within its conventional hydrostatic stability field.

  3. Microwave-Assisted Superheating and/or Microwave-Specific Superboiling (Nucleation-Limited Boiling) of Liquids Occurs under Certain Conditions but is Mitigated by Stirring.

    PubMed

    Ferrari, Anthony; Hunt, Jacob; Stiegman, Albert; Dudley, Gregory B

    2015-12-04

    Temporary superheating and sustained nucleation-limited "superboiling" of unstirred liquids above the normal atmospheric boiling point have been documented during microwave heating. These phenomena are reliably observed under prescribed conditions, although the duration (of superheating) and magnitude (of superheating and superboiling) vary according to system parameters such as volume of the liquid and the size and shape of the vessel. Both phenomena are mitigated by rapid stirring with an appropriate stir bar and/or with the addition of boiling chips, which provide nucleation sites to support the phase-change from liquid to gas. With proper experimental design and especially proper stirring, the measured temperature of typical organic reaction mixtures heated at reflux will be close to the normal boiling point temperature of the solvent, whether heated using microwave radiation or conventional convective heat transfer. These observations are important to take into consideration when comparing reaction rates under conventional and microwave heating.

  4. Microwave-Assisted Superheating and/or Microwave-Specific Superboiling (Nucleation-Limited Boiling) of Liquids Occurs under Certain Conditions but is Mitigated by Stirring.

    PubMed

    Ferrari, Anthony; Hunt, Jacob; Stiegman, Albert; Dudley, Gregory B

    2015-01-01

    Temporary superheating and sustained nucleation-limited "superboiling" of unstirred liquids above the normal atmospheric boiling point have been documented during microwave heating. These phenomena are reliably observed under prescribed conditions, although the duration (of superheating) and magnitude (of superheating and superboiling) vary according to system parameters such as volume of the liquid and the size and shape of the vessel. Both phenomena are mitigated by rapid stirring with an appropriate stir bar and/or with the addition of boiling chips, which provide nucleation sites to support the phase-change from liquid to gas. With proper experimental design and especially proper stirring, the measured temperature of typical organic reaction mixtures heated at reflux will be close to the normal boiling point temperature of the solvent, whether heated using microwave radiation or conventional convective heat transfer. These observations are important to take into consideration when comparing reaction rates under conventional and microwave heating. PMID:26690096

  5. Pure water injection into porous rock with superheated steam and salt in a solid state

    NASA Astrophysics Data System (ADS)

    Montegrossi, G.; Tsypkin, G.; Calore, C.

    2012-04-01

    Most of geothermal fields require injection of fluid into the hot rock to maintain pressure and productivity. The presence of solid salt in porous space may cause an unexpected change in the characteristics of the reservoir and produced fluids, and dramatically affect the profitability of the project. We consider an injection problem of pure water into high temperature geothermal reservoir, saturated with superheated vapour and solid salt. Pure water moves away from injection point and dissolves solid salt. When salty water reaches the low-pressure hot domain, water evaporation occurs and, consequently, salt precipitates. We develop a simplified analytical model of the process and derive the similarity solutions for a 1-D semi-infinite reservoir. These solutions are multi-valued and describe the reduction in permeability and porosity due to salt precipitation at the leading boiling front. If the parameters of the system exceed critical values, then similarity solution ceases to exist. We identify this mathematical behaviour with reservoir sealing in the physical system. The TOUGH2-EWASG code has been used to verify this hypothesis and investigate the precipitate formation for an idealized bounded 1-D geothermal system of a length of 500 m with water injection at one extreme and fluid extraction at the other one. Both boundaries are kept at constant pressure and temperature. The result for the semi-infinite numerical model show that the monotonic grow of the solid salt saturation to reach asymptotic similarity solution generally occurs over a very large length starting from the injection point. Reservoir sealing occurs if solid salt at the initial state occupies a considerable part of the porous space. Numerical experiments for the bounded 500 m system demonstrate that a small amount of salt is enough to get reservoir sealing. Generally, salt tend to accumulate near the production well, and salt plug forms at the elements adjacent to the extraction point. This type

  6. Hydrogen bond dynamics of superheated water and methanol by ultrafast IR-pump and EUV-photoelectron probe spectroscopy.

    PubMed

    Vöhringer-Martinez, E; Link, O; Lugovoy, E; Siefermann, K R; Wiederschein, F; Grubmüller, H; Abel, B

    2014-09-28

    Supercritical water and methanol have recently drawn much attention in the field of green chemistry. It is crucial to an understanding of supercritical solvents to know their dynamics and to what extent hydrogen (H) bonds persist in these fluids. Here, we show that with femtosecond infrared (IR) laser pulses water and methanol can be heated to temperatures near and above their critical temperature Tc and their molecular dynamics can be studied via ultrafast photoelectron spectroscopy at liquid jet interfaces with high harmonics radiation. As opposed to previous studies, the main focus here is the comparison between the hydrogen bonded systems of methanol and water and their interpretation by theory. Superheated water initially forms a dense hot phase with spectral features resembling those of monomers in gas phase water. On longer timescales, this phase was found to build hot aggregates, whose size increases as a function of time. In contrast, methanol heated to temperatures near Tc initially forms a broad distribution of aggregate sizes and some gas. These experimental features are also found and analyzed in extended molecular dynamics simulations. Additionally, the simulations enabled us to relate the origin of the different behavior of these two hydrogen-bonded liquids to the nature of the intermolecular potentials. The combined experimental and theoretical approach delivers new insights into both superheated phases and may contribute to understand their different chemical reactivities. PMID:25102451

  7. Radiation linear energy transfer and drop size dependence of the low frequency signal from tiny superheated droplets

    NASA Astrophysics Data System (ADS)

    Seth, Susnata; Das, Mala

    2016-11-01

    The bubble nucleation in superheated tiny droplets of R-12 (CCl2F2, boiling point: -29.8 °C) induced by neutrons and α-particles has been observed using condenser microphone as an acoustic sensor. The superheated droplets used in these experiments are of very small radii having distribution with main peak around 2-3 μm expanding until about 40 μm. The low frequency component of the acoustic shock wave released during bubble nucleation has been measured with condenser microphone and the analysis has been done using ROOT software. Pulses due to bubble nucleation have been recorded in the presence of 241Am-Be neutron source (few keV to about 10 MeV) and 241Am alpha-source (5.48 MeV with intensity 85.2%). The observables related to the power associated with bubble nucleation (P) and the area under the frequency spectrum of the signal (PFreq) have been estimated for the α-particle and neutron induced events. It shows that the α-particle induced bubble nucleation signals are of lower intensity than those obtained from the neutron induced bubble nucleation signals. This phenomenon as observed with tiny droplets is opposite to that observed so far for the larger droplets.

  8. Local and bulk melting of shocked columnar nanocrystalline Cu: Dynamics, anisotropy, premelting, superheating, supercooling, and re-crystallization.

    PubMed

    He, A M; Duan, S Q; Shao, J L; Wang, P; Luo, S N

    2013-08-21

    We perform large-scale molecular dynamics simulations to study shock-induced melting transition of idealized hexagonal columnar nanocrystalline Cu. The as-constructed nanocrystalline Cu consists of unrotated (reference) and rotated columnar crystals, relative to the columnar axis. Shock loading is applied along three principal directions of the columnar Cu: two transverse (zigzag and armchair) and one longitudinal directions. Dynamic local melting processes are highly anisotropic with respect to the shock directions. For the transverse directions, hotspot effect and disparate dynamic responses of grains with different orientations may lead to partial or complete premelting of the initially rotated grains, which in turn leads to transient supercooling and heterogeneous recrystallization, and thus, the formation of nanocrystalline solids with modified grain structures or solid-liquid mixtures, depending on the extent of supercooling. With increasing shock strengths, the reference grains melt heterogeneously at interfaces and homogeneously inside. Conversely, "bulk" premelting of the rotated grains is absent for the longitudinal direction, except for grain boundary melting. The progression of recrystallization or heterogenous melting diminishes and eventually eliminates the transient premelting or superheating of the system via latent heat and thermal diffusion. Premelting or superheating appears unlikely for bulk melting or well-defined Hugoniot states, if the thermal and mechanical equilibria are achieved, and the thermodynamic melting curve coincides with the partial melting Hugoniot states of a polycrystalline solid.

  9. Study of gamma ray response of R404A superheated droplet detector using a two-state model.

    PubMed

    Mondal, P K; Chatterjee, B K

    2013-07-01

    The superheated droplet detector (SDD) is known to be gamma ray insensitive below a threshold temperature which made them excellent candidates for neutron detection in the presence of gamma rays. Above the threshold temperature, the gamma ray detection efficiency increases with increase in temperature. In this work the gamma ray threshold temperature has been studied for SDD using R404A as the active liquid and is compared to the theoretical prediction. The temperature variation of gamma ray detection efficiency and interstate transition kinetics has also been studied using a two-state model. The experiments are performed at the ambient pressure of 1 atm and in the temperature range of 17-32 °C using a 662 keV (1)(37)Cs gamma ray source. PMID:23528644

  10. ARE the Merensky Reef and Massive Chromitites of the Bushveld Complex Formed from Crystal Slurries or Superheated Magmas?

    NASA Astrophysics Data System (ADS)

    Latypov, R.; Chistyakova, S.

    2014-12-01

    Many recent models attribute the origin of the Merensky Reef and massive chromitites of the Bushveld Complex, South Africa to replenishment of a magma chamber by phenocryst-rich magmas (crystal slurries). In particular, the emplacement of chromite-rich slurries from the staging chamber is currently thought to be responsible for the formation of massive chromitites of the Bushveld Complex. There are, however, first-order observations that are not compatible with this popular idea. One of the key features of the Merensky Reef and almost all layers of massive chromitites is their close association with so-called potholes, the circular to elliptical depressions with gently to steeply inclined sidewalls that are transgressive relative to their footwall rocks. Portions of magmatic stratigraphy are totally absent from the footwall rocks in pothole areas. Here we summarize abundant field evidence from several localities of the Eastern and Western Bushveld Complex that provide strong support to an idea that these portions of footwall rocks were thermally and partly mechanically eroded away by new magma pulses refilling the chamber. To be able to erode the footwall rocks so effectively, the new magmas must have been superheated upon emplacement into the chamber (no phenocrysts in the magmas). Otherwise the phenocrysts will immediately settle to the floor of the chamber to form a blanket protecting footwall rocks from the thermal erosion. The geological observations thus suggest that the origin of the Merensky Reef and massive chromitites must be tackled in the frame of the models that involve the emplacement of superheated, rather than phenocryst-laden magmas. The important lesson to be drawn from this study is that the field observations are still one of the primary tools for the rigorous testing of our hypotheses in modern igneous/ore petrology.

  11. Direct simulation of melting a cryogenic surface with a two-dimensional axisymmetric turbulent superheated vapor jet

    NASA Astrophysics Data System (ADS)

    Baran, Adam J.

    This dissertation presents original research into the melting process of a downward facing cryogenic solid hydrogen surface subject to a two dimensional axisymmetric jet impingement flow of superheated hydrogen vapor. The motivation for the study is to investigate concepts of storing rocket propellants as a solid and rapidly melting the solid for liquid propellant delivery to a rocket engine. The present study considers a more favorable liquid removal arrangement than prior (1970s) experiments which melted solid hydrogen at the bottom of a cryostat. This is a numerical study that involves computation fluid dynamic (CFD) simulation of four distinct physical phenomena: (1) melting, (2) jet impingement heat transfer (JIHT), (3) multiphase transport, and (4) film breakup/droplet formation. The volume of fluid (VOF) method is used with the V2F turbulence model in a commercial CFD Navier-Stokes solver (FLUENT) to investigate the multiphase nature of melt transport and its interaction with the vapor stream; i.e., the phenomena relevant to effective heat transfer between the vapor and the melting interface. The goal of the research is: (1) to develop a numerical method to study the problem and (2) evaluate several simple configurations to begin investigating relevant phenomena for the purpose of enhancing melting rate. Many options exist for the vapor to interact with the solid surface. The scope of this initial research is limited to a steady jet of single phase superheated hydrogen vapor at fixed jet exit conditions (T = 525 R and Re = 11,000) at a fixed jet standoff ( H/D = 1.0). Condensation/vaporization are not considered. Although film breakup/droplet formation is a phenomenon where two dimensional features evolve into three dimensional events, this phenomenon is approximated as two dimensional to allow a computationally tractable problem for this initial study. Calculations are performed validating the numerical method for melting and JIHT against known results

  12. TH{_}PULSE Program for Calculating Infiltration of Episodic Liquid Fingers in Superheated Rock Fractures

    SciTech Connect

    J.T. Birkholzer

    2002-06-01

    This report describes the code TH{_}PULSE developed at the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab). The code handles gravity-driven flow of episodic infiltration events entering above-boiling rock-temperature regions. Such temperature conditions are expected, for example, after emplacement of heat-generating nuclear waste in underground repositories. Complex fluid-flow and heat-transfer phenomena occur, as the infiltrating water is subject to vigorous boiling from the hot rock. A new efficient semi-analytical method is presented herein that simulates such phenomena. It is assumed that flow forms in localized preferential flow paths (referred to as ''fingers''). The first section of this report gives the conceptual and mathematical background for the solution scheme. The second section is a user's manual for TH{_}PULSE, providing all information required to run the code, including a detailed description of the input and output files. In the third section, the new solution scheme is applied to several test cases. Sample simulations are performed for conditions representative of the potential nuclear waste repository at Yucca Mountain, Nevada. A brief summary is given in Section 4.

  13. Fourier-transform infrared spectroscopy for the assesment of soil organic carbon removal by superheated water: preliminary results

    NASA Astrophysics Data System (ADS)

    Ćirić, Vladimir; Švarc-Gajić, Jaroslava; Jović, Branislav; Kordić, Branko; Šodić, Bojana; Šeremešić, Srđan

    2016-04-01

    Soil organic carbon (SOC) is key determinant of soil quality and thus can considerably affect ecosystem services, environmental and global climate changes. Consequently, characterization of SOC and its fractions is of an increasing interest. No standard method for assessment of SOC fractions was adopted. Subcritical water extraction (SCWE) provides great flexibility and could be used for the extraction of different organic compounds from soil as well as for the removal of different SOC fractions from soil. The purpose of this study was to assess the potential of the treatment with subcritical water (SCW), or superheated water, in combination with different catalysts to affect different SOC fractions and thus its spectral bands. Subcritical water treatment of soil samples was performed at 180°C and pressure of 40 bars, whilst three different catalysts were separately applied: titanium dioxide (TiO2), cerium sulfate Ce (SO4)2 and zeolite. Fourier-transform infrared (FTIR) spectroscopy was used as known technique for SOC characterization. After the SCW treatment the efficiency of catalysts regarding the removal of SOC fractions was studied via spectral bands of treated soil samples. Soil treatment with SCW without catalyst caused most changes in the region of 3800-3000 nm (-OH) that corresponds to cellulose. The aromatic compounds (C=C groups) in the region of 1800-1550 nm that corresponds to stable SOC fractions (humic materials and lignin) was strongly affected by treatment with TiO2. Aliphatic compounds in the region of 1500-1350 nm (C-H and C-O groups) were mostly affected by SCW in combination with zeolite, while SCW in combination with Ce(SO4)2 besides aliphatic region altered aromatic groups in lesser extent. Zeolite in combination with SCW was proved to be good tool for aliphatic (labile) SOC removal, while TiO2 in combination with SCW was proved efficient for the removal of aromatic (stable) SOC fractions.

  14. Laboratory study of the effects of combustion gases on retorting of Green River oil shale with superheated steam

    SciTech Connect

    Tyler, A.L.; Bullen, E.A.; Jacobs, H.R.

    1983-04-01

    The leached zone of the Parachute Creek member of the Piceance Basin in the Green River Formation has a unique natural porosity that makes it a likely source for in-situ production of oil from oil shale by injection of superheated steam. The Equity Oil Co. of Salt Lake City, in cooperation with the U. S. Department of Energy, carried out field tests using surface generated steam. Difficulties in delivering steam of sufficiently high temperature to the formation resulted in an experiment which was only marginally successful yielding less than 1 percent of the estimated 300,000 barrels of oil in place. In 1981, personnel at Sandia National Laboratory suggested that a downhole steam generator which could produce steam at temperatures in excess of 1000/sup 0/F (538/sup 0/C) at depth could well solve the temperature problem. In order to evaluate the effects of combustion gases which would be injected along with steam, should a downhole steam generator be used, laboratory studies have been completed using steam diluted with CO/sub 2/ and with CO/sub 2/ and N/sub 2/ as the heating medium. Results of experiments in an autoclave reactor and in a laboratory retort are reported. The temperature, residence time, and partial pressure of steam are the parameters which effect oil yield and oil quality. Oil properties are reported for several experimental conditions and include oil yield, boiling point distributions, pour points, gravity, and elemental and hydrocarbon-type analyses. Both the autoclave and laboratory retort experiments indicate that CO/sub 2/ and N/sub 2/ do not take a reactive part in the formation of oils except as they dilute the steam. However, the presence of CO/sub 2/ in the gaseous atmosphere during retorting does promote a low-temperature transformation of dolomite to calcite in the inorganic matrix of the oil shale.

  15. Transcriptional response of selected genes of Salmonella enterica serovar Typhimurium biofilm cells during inactivation by superheated steam.

    PubMed

    Ban, Ga-Hee; Kang, Dong-Hyun; Yoon, Hyunjin

    2015-01-01

    Superheated steam (SHS), produced by the addition of heat to saturated steam (SS) at the same pressure, has great advantages over conventional heat sterilization due to its high temperature and accelerated drying rate. We previously demonstrated that treatment with SHS at 200°C for 10 sec inactivated Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes biofilm cells on the surface of stainless steel to below the detection limit. However, bacteria withstanding heat stress become more resistant to other stress conditions, and may be more virulent when consumed by a host. Herein, we studied the transcriptional regulation of genes important for stress resistance and virulence in Salmonella biofilms after SHS treatments. Genes encoding heat shock proteins and general stress resistance proteins showed transcriptional surges after 1 sec of SHS treatment at 200°C, with parallel induction of stress-related regulator genes including rpoE, rpoS, and rpoH. Interestingly, Salmonella biofilm cells exposed to SHS showed decreased transcription of flagella and Salmonella pathogenicity island-1 (SPI-1) genes required for motility and invasion of host cells, respectively, whereas increased transcription of SPI-2 genes, important for bacterial survival and replication inside host cells, was detected. When the transcriptional response was compared between cells treated with SHS (200°C) and SS (100°C), SHS caused immediate changes in gene expression by shorter treatments. Understanding the status of Salmonella virulence and stress resistance induced by SHS treatments is important for wider application of SHS in controlling Salmonella biofilm formation during food production.

  16. HPLC analysis of ecdysteroids in plant extracts using superheated deuterium oxide with multiple on-line spectroscopic analysis (UV, IR, 1H NMR, and MS).

    PubMed

    Louden, Dave; Handley, Alan; Lafont, Rene; Taylor, Steve; Sinclair, Ian; Lenz, Eva; Orton, Timothy; Wilson, Ian D

    2002-01-01

    HPLC, using superheated D20 as the mobile phase, combined with on-line characterization via a combination of diode array UV, 1H NMR, FT-IR spectroscopy, and mass spectrometry has been used for the analysis of a standard of 20-hydroxyecdysone- and ecdysteroid-containing plant extracts. This combination of spectrometers enabled the on-flow collection of UV, 1H NMR, IR, and mass spectra not only for pure 20-hydroxyecdysone (100-400 microg on column) but also the major ecdysteroids present in crude extracts of Silene otites, Silene nutans, and Silene frivaldiskyana. The ecdysteroids unequivocally identified in these extracts included 20-hydroxyecdysone, polypodine B, and integristerone A.

  17. Erasing conformational limitations in N,N'-1,4-butanediyl-bis(6-hydroxy-hexanamide) crystallization from the superheated state of water.

    PubMed

    Harings, Jules A W; Yao, Yefeng; Graf, Robert; van Asselen, Otto; Broos, Rene; Rastogi, Sanjay

    2009-07-01

    Aliphatic polyamides consist of regularly distributed amide moieties located in an aliphatic chain, off which the segment length can be varied. The crystallization and hence the eventual performance of the material can be tailored by changing the aliphatic lengths, and thus the hydrogen bonding density and the directional chemical positioning of the amide motifs. In this paper, N,N'-1,4-butanediyl-bis(6-hydroxy-hexanamide) crystallized either from the melt or from the superheated state of water is investigated. A comparison with N,N'-1,2-ethanediyl-1,2-bis(6-hydroxy-hexanamide) reveals the role of the hydrogen bonding density on the accommodation of water molecules in amide based crystals grown from the superheated state of water. However, wide-angle X-ray diffraction (WAXD), Fourier transform infrared (FTIR), and solid state 1H and 13C NMR spectroscopy reveal hydrogen bonding between the amide planes, while aliphatic polyamides and N,N'-1,2-diethyl-bis(6-hydroxy-hexanamide) feature hydrogen bonds that reside within the amide plane only. As a consequence, the role of N,N'-1,4-butanediyl-bis(6-hydroxy-hexanamide) crystals as a model system for polyamide 4Y polymers is questionable. However, the thermodynamic and structural behavior as function of temperature is determined by a balance between thermally introduced gauche conformers and hydrogen bonding efficiencies. These crystals enable a thorough investigation in the effect of superheated water on the crystallization of these uniquely hydrogen bonded molecules. Crystallization from the superheated state of water results in denser molecular packing and enhanced hydrogen bonding efficiencies. The induced spatial confinement hinders molecular motion upon heating, and thermodynamically more stable crystals are observed. Although the amide-hydroxyl hydrogen bonded crystals do not favor the accommodation of physically bound water molecules in the lattice, saturation of the amide motifs during crystallization erases

  18. The role of superheating in the formation of Glass Mountain obsidians (Long Valley, CA) inferred through crystallization of sanidine

    NASA Astrophysics Data System (ADS)

    Waters, Laura E.; Andrews, Benjamin J.

    2016-10-01

    crystals (and other mineral phases) must have an associated kinetic effect(s) that efficiently hinders crystal nucleation and growth. Decompression experiments conducted in this study and from the literature collectively demonstrate that the simplest way to inhibit nucleation during degassing-induced crystallization is to initiate degassing ± cooling from superliquidus conditions, and therefore, the Glass Mountain obsidians were superheated prior to crystallization.

  19. Effectiveness of superheated steam for inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Salmonella Enteritidis phage type 30, and Listeria monocytogenes on almonds and pistachios.

    PubMed

    Ban, Ga-Hee; Kang, Dong-Hyun

    2016-03-01

    This study was undertaken to evaluate the effectiveness of superheated steam (SHS) on the inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Salmonella Enteritidis phage type (PT) 30 and Listeria monocytogenes on almonds and in-shell pistachios and to determine the effect of superheated steam heating on quality by measuring color and texture changes. Almonds and in-shell pistachios inoculated with four foodborne pathogens were treated with saturated steam (SS) at 100 °C and SHS at 125, 150, 175, and 200 °C for various times. Exposure of almonds and pistachios to SHS for 15 or 30s at 200 °C achieved >5l og reductions among all tested pathogens without causing significant changes in color values or texture parameters (P>0.05). For both almonds and pistachios, acid and peroxide values (PV) following SS and SHS treatment for up to 15s and 30s, respectively, were within the acceptable range (PV<1.0 meq/kg). These results show that thermal application of 200 °C SHS treatment for 15s and 30s did not affect the quality of almonds and pistachios, respectively. Therefore, SHS treatment is a very promising alternative technology for the tree nuts industry by improving inactivation of foodborne pathogens on almonds and pistachios while simultaneously reducing processing time.

  20. Characterizing and Exploring the Formation Mechanism of Salt Deposition by Reusing Advanced-softened, Silica-rich, Oilfield-produced Water (ASOW) in Superheated Steam Pipeline

    NASA Astrophysics Data System (ADS)

    Dong, Bin; Xu, Ying; Lin, Senmin; Dai, Xiaohu

    2015-11-01

    To dispose of large volumes of oilfield-produced water, an environmentally friendly method that reuses advanced-softened, silica-rich, oilfield-produced water (ASOW) as feedwater was implemented via a 10-month pilot-scale test in oilfield. However, salt deposition detrimental to the efficiency and security of steam injection system was generated in superheated steam pipeline. To evaluate the method, the characteristics and formation mechanism of the deposition were explored. The silicon content and total hardness of the ASOW were 272.20 mg/L and 0.018 mg/L, respectively. Morphology and composition of the deposition were determined by scanning electron microscope-energy dispersive spectrometry (SEM-EDS), inductively coupled plasma-mass spectroscopy (ICP-MS), X-ray diffraction (XRD), laser Raman spectroscopy (LRS) and X-ray photoelectron spectroscopy (XPS). Na2Si2O5, Na2CO3 and trace silanes were identified in the deposition. In addition, the solubility of the deposition was about 99%, suggesting that it is very different from traditional scaling. The results of a simulation experiment and thermal analysis system (TGA and TG-FTIR) proved that Na2CO3 and Si(OH)4 (gas) are involved in the formation of Na2Si2O5, which is ascribed mainly to the temperature difference between the superheated steam and the pipe wall. These findings provide an important reference for improving the reuse of ASOW and reducing its deposition.

  1. Characterizing and Exploring the Formation Mechanism of Salt Deposition by Reusing Advanced-softened, Silica-rich, Oilfield-produced Water (ASOW) in Superheated Steam Pipeline.

    PubMed

    Dong, Bin; Xu, Ying; Lin, Senmin; Dai, Xiaohu

    2015-11-26

    To dispose of large volumes of oilfield-produced water, an environmentally friendly method that reuses advanced-softened, silica-rich, oilfield-produced water (ASOW) as feedwater was implemented via a 10-month pilot-scale test in oilfield. However, salt deposition detrimental to the efficiency and security of steam injection system was generated in superheated steam pipeline. To evaluate the method, the characteristics and formation mechanism of the deposition were explored. The silicon content and total hardness of the ASOW were 272.20 mg/L and 0.018 mg/L, respectively. Morphology and composition of the deposition were determined by scanning electron microscope-energy dispersive spectrometry (SEM-EDS), inductively coupled plasma-mass spectroscopy (ICP-MS), X-ray diffraction (XRD), laser Raman spectroscopy (LRS) and X-ray photoelectron spectroscopy (XPS). Na2Si2O5, Na2CO3 and trace silanes were identified in the deposition. In addition, the solubility of the deposition was about 99%, suggesting that it is very different from traditional scaling. The results of a simulation experiment and thermal analysis system (TGA and TG-FTIR) proved that Na2CO3 and Si(OH)4 (gas) are involved in the formation of Na2Si2O5, which is ascribed mainly to the temperature difference between the superheated steam and the pipe wall. These findings provide an important reference for improving the reuse of ASOW and reducing its deposition.

  2. Characterizing and Exploring the Formation Mechanism of Salt Deposition by Reusing Advanced-softened, Silica-rich, Oilfield-produced Water (ASOW) in Superheated Steam Pipeline.

    PubMed

    Dong, Bin; Xu, Ying; Lin, Senmin; Dai, Xiaohu

    2015-01-01

    To dispose of large volumes of oilfield-produced water, an environmentally friendly method that reuses advanced-softened, silica-rich, oilfield-produced water (ASOW) as feedwater was implemented via a 10-month pilot-scale test in oilfield. However, salt deposition detrimental to the efficiency and security of steam injection system was generated in superheated steam pipeline. To evaluate the method, the characteristics and formation mechanism of the deposition were explored. The silicon content and total hardness of the ASOW were 272.20 mg/L and 0.018 mg/L, respectively. Morphology and composition of the deposition were determined by scanning electron microscope-energy dispersive spectrometry (SEM-EDS), inductively coupled plasma-mass spectroscopy (ICP-MS), X-ray diffraction (XRD), laser Raman spectroscopy (LRS) and X-ray photoelectron spectroscopy (XPS). Na2Si2O5, Na2CO3 and trace silanes were identified in the deposition. In addition, the solubility of the deposition was about 99%, suggesting that it is very different from traditional scaling. The results of a simulation experiment and thermal analysis system (TGA and TG-FTIR) proved that Na2CO3 and Si(OH)4 (gas) are involved in the formation of Na2Si2O5, which is ascribed mainly to the temperature difference between the superheated steam and the pipe wall. These findings provide an important reference for improving the reuse of ASOW and reducing its deposition. PMID:26608736

  3. Characterizing and Exploring the Formation Mechanism of Salt Deposition by Reusing Advanced-softened, Silica-rich, Oilfield-produced Water (ASOW) in Superheated Steam Pipeline

    PubMed Central

    Dong, Bin; Xu, Ying; Lin, Senmin; Dai, Xiaohu

    2015-01-01

    To dispose of large volumes of oilfield-produced water, an environmentally friendly method that reuses advanced-softened, silica-rich, oilfield-produced water (ASOW) as feedwater was implemented via a 10-month pilot-scale test in oilfield. However, salt deposition detrimental to the efficiency and security of steam injection system was generated in superheated steam pipeline. To evaluate the method, the characteristics and formation mechanism of the deposition were explored. The silicon content and total hardness of the ASOW were 272.20 mg/L and 0.018 mg/L, respectively. Morphology and composition of the deposition were determined by scanning electron microscope–energy dispersive spectrometry (SEM-EDS), inductively coupled plasma–mass spectroscopy (ICP-MS), X-ray diffraction (XRD), laser Raman spectroscopy (LRS) and X-ray photoelectron spectroscopy (XPS). Na2Si2O5, Na2CO3 and trace silanes were identified in the deposition. In addition, the solubility of the deposition was about 99%, suggesting that it is very different from traditional scaling. The results of a simulation experiment and thermal analysis system (TGA and TG-FTIR) proved that Na2CO3 and Si(OH)4 (gas) are involved in the formation of Na2Si2O5, which is ascribed mainly to the temperature difference between the superheated steam and the pipe wall. These findings provide an important reference for improving the reuse of ASOW and reducing its deposition. PMID:26608736

  4. Effectiveness of superheated steam for inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Salmonella Enteritidis phage type 30, and Listeria monocytogenes on almonds and pistachios.

    PubMed

    Ban, Ga-Hee; Kang, Dong-Hyun

    2016-03-01

    This study was undertaken to evaluate the effectiveness of superheated steam (SHS) on the inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Salmonella Enteritidis phage type (PT) 30 and Listeria monocytogenes on almonds and in-shell pistachios and to determine the effect of superheated steam heating on quality by measuring color and texture changes. Almonds and in-shell pistachios inoculated with four foodborne pathogens were treated with saturated steam (SS) at 100 °C and SHS at 125, 150, 175, and 200 °C for various times. Exposure of almonds and pistachios to SHS for 15 or 30s at 200 °C achieved >5l og reductions among all tested pathogens without causing significant changes in color values or texture parameters (P>0.05). For both almonds and pistachios, acid and peroxide values (PV) following SS and SHS treatment for up to 15s and 30s, respectively, were within the acceptable range (PV<1.0 meq/kg). These results show that thermal application of 200 °C SHS treatment for 15s and 30s did not affect the quality of almonds and pistachios, respectively. Therefore, SHS treatment is a very promising alternative technology for the tree nuts industry by improving inactivation of foodborne pathogens on almonds and pistachios while simultaneously reducing processing time. PMID:26773253

  5. Theoretical prediction of physical and chemical characteristics of the first drop'' of condensate from superheated geothermal steam: Implications for corrosion and scaling in turbines

    SciTech Connect

    Andreussi, P. . Dipartimento Scienze e Tecnologie Chimiche); Corsi, R. ); Guidi, M.; Marini, L. )

    1994-06-01

    This paper describes a method for computing: (1) the chemical composition of the first drop of condensate which forms at dew-point temperature through expansion of superheated steam, and (2) the saturation index of the drop with respect to relevant solid phases, such as halite, amorphous silica, boric acid, borax and sal ammoniac. Boiling-point elevation is taken into account in these calculations. Preliminary application to some wells in the Larderello geothermal field indicate that: (1) the high concentration of HCl in the steam causes both the low pH and very high TDS of the first drop; (2) the lower the dew-point temperature, the higher the TDS of the first drop; (3) for a given chemical composition, the lower the steam pressure, the higher the risk of corrosion and scaling in the steam path.

  6. A nuclear driven metallic vapor MHD coupled with MPD thrusters

    NASA Technical Reports Server (NTRS)

    Anghaie, Samim; Kumar, Ratan

    1991-01-01

    Nuclear energy as a source of power for space missions, represents an enabling technology for advanced and ambitious space applications. Nuclear fuel in a gaseous or liquid form has been configured as a promising and practical candidate in this regard. The present study investigates and performs a feasibility analysis of an innovative concept for space power generation and propulsion. The system embodies a conceptual nuclear reactor with an MHD generator and coupled to MPD thrusters. The reactor utilizes liquid uranium in droplet form as fuel and superheated metallic vapor as the working fluid. This ultrahigh temperature vapor core reactor brings forward varied and challenging technical issues, and it has been addressed to in this paper. A parametric study of the conceived system has been performed in a qualitative and quantitative manner. Preliminary results show enough promise for further indepth analysis of this novel system.

  7. Laboratory modeling of in-situ retorting of oil shale by superheated-steam injection. BX in-situ oil shale project

    SciTech Connect

    Dougan, P.M.

    1981-08-03

    The laboratory study has shown that retorting of oil shale by a superheated steam is practical; yield of evolved product is given by 1-X = 1-e/sup Kt/, where K = -4.83 x 10/sup 14/e/sup -//sup 22,900/T/. Evolved oil has a high pour point 70 to 82/sup 0/F low API gravity approx. 21, but it is cracked in steam above 525/sup 0/F, resulting in in-situ recovered oil with low pour point below 30/sup 0/F. The Parachute Creek formation contains carbonates and bicarbonates which accounts for nearly all the CO/sub 2/ in the off-gases; thus no water-shift or water-gas reaction probably is taking place. The oils have lower molecular weight and larger fractions of naptha, light distillate and light gas oil than ordinary shale oils. The nitrogen, sulfur, and oxygen are lowered. The steam cracking leads to a less polar product. 48 figures. (DLC)

  8. Bubble chambers for experiments in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    DiGiovine, B.; Henderson, D.; Holt, R. J.; Raut, R.; Rehm, K. E.; Robinson, A.; Sonnenschein, A.; Rusev, G.; Tonchev, A. P.; Ugalde, C.

    2015-05-01

    A bubble chamber has been developed to be used as an active target system for low energy nuclear astrophysics experiments. Adopting ideas from dark matter detection with superheated liquids, a detector system compatible with γ-ray beams has been developed. This detector alleviates some of the limitations encountered in standard measurements of the minute cross-sections of interest to stellar environments. While the astrophysically relevant nuclear reaction processes at hydrostatic burning temperatures are dominated by radiative captures, in this experimental scheme we measure the time-reversed processes. Such photodisintegrations allow us to compute the radiative capture cross-sections when transitions to excited states of the reaction products are negligible. Due to the transformation of phase space, the photodisintegration cross-sections are up to two orders of magnitude higher. The main advantage of the new target-detector system is a density several orders of magnitude higher than conventional gas targets. Also, the detector is virtually insensitive to the γ-ray beam itself, thus allowing us to detect only the products of the nuclear reaction of interest. The development and the operation as well as the advantages and disadvantages of the bubble chamber are discussed.

  9. Experimental investigation on combustion of hydrogen-oxygen and methane-oxygen mixtures in the medium of low-superheated steam

    NASA Astrophysics Data System (ADS)

    Pribaturin, N. A.; Fedorov, V. A.; Alekseev, M. V.; Bogomolov, A. R.; Sorokin, A. L.; Azikhanov, S. S.; Shevyrev, S. A.

    2016-05-01

    Experimental data are represented on the investigation of combustion of hydrogen-oxygen and methane-oxygen mixtures in the medium of low-superheated (initial temperature of approximately 150°C) steam at atmospheric pressure. The influence of the ratio of mass flows of the combustible mixture and steam on the qualitative composition of combustion products and the temperature of produced steam is revealed. Main laws for combustion of the hydrogen-oxygen mixture within the steam flow, which affect the completeness of mixture combustion, are determined. Experimental data on the influence of concentrations of the hydrogen-oxygen mixture within the flow of the steam and the combustible mixture upon the completeness of combustion are given. It is found that, when burning the hydrogen-oxygen mixture within the steam flow with a temperature of 1000-1200°C, it is possible using a variation of the combustible mixture flow. At the same time, the volume fraction of noncondensable gases in the produced steam is no more than 2%. It is revealed that there are several combustion modes of the hydrogen-oxygen mixture within the steam flow, in which, in one case, the steam always suppresses combustion and, in another one, detonation of the combustible mixture combustible mixture occurs. It is found that with the excess air factor close to unit, the combustion of the methane-oxygen mixture within steam and the vapor conversion of methane, which result in the appearance of free hydrogen in the produced high-temperature steam, are possible. The description and the principle of the operation of the experimental bench for investigation of combustion of methane-oxygen and hydrogen-oxygen mixtures in the medium of steam are given. Results of experimental investigations of burning fuel and oxygen in the medium of steam are used in the development of a steam superheater for a hightemperature steam turbine.

  10. Coupled phase field, heat conduction, and elastodynamic simulations of kinetic superheating and nanoscale melting of aluminum nanolayer irradiated by picosecond laser.

    PubMed

    Hwang, Yong Seok; Levitas, Valery I

    2015-12-21

    An advanced continuum model for nanoscale melting and kinetic superheating of an aluminum nanolayer irradiated by a picosecond laser is formulated. Barrierless nucleation of surface premelting and melting occurs, followed by a propagation of two solid-melt interfaces toward each other and their collision. For a slow heating rate of Q = 0.015 K ps(-1) melting occurs at the equilibrium melting temperature under uniaxial strain conditions T = 898.1 K (i.e., below equilibrium melting temperature Teq = 933.67 K) and corresponding biaxial stresses, which relax during melting. For a high heating rate of Q = 0.99-84 K ps(-1), melting occurs significantly above Teq. Surprisingly, an increase in heating rate leads to temperature reduction at the 3 nm wide moving interfaces due to fast absorption of the heat of fusion. A significant, rapid temperature drop (100-500 K, even below melting temperature) at the very end of melting is revealed, which is caused by the collision of two finite-width interfaces and accelerated melting in about the 5 nm zone. For Q = 25-84 K ps(-1), standing elastic stress waves are observed in a solid with nodal points at the moving solid-melt interfaces, which, however, do not have a profound effect on melting time or temperatures. When surface melting is suppressed, barrierless bulk melting occurs in the entire sample, and elastodynamic effects are more important. Good correspondence with published, experimentally-determined melting time is found for a broad range of heating rates. Similar approaches can be applied to study various phase transformations in different materials and nanostructures under high heating rates.

  11. Coupled phase field, heat conduction, and elastodynamic simulations of kinetic superheating and nanoscale melting of aluminum nanolayer irradiated by picosecond laser.

    PubMed

    Hwang, Yong Seok; Levitas, Valery I

    2015-12-21

    An advanced continuum model for nanoscale melting and kinetic superheating of an aluminum nanolayer irradiated by a picosecond laser is formulated. Barrierless nucleation of surface premelting and melting occurs, followed by a propagation of two solid-melt interfaces toward each other and their collision. For a slow heating rate of Q = 0.015 K ps(-1) melting occurs at the equilibrium melting temperature under uniaxial strain conditions T = 898.1 K (i.e., below equilibrium melting temperature Teq = 933.67 K) and corresponding biaxial stresses, which relax during melting. For a high heating rate of Q = 0.99-84 K ps(-1), melting occurs significantly above Teq. Surprisingly, an increase in heating rate leads to temperature reduction at the 3 nm wide moving interfaces due to fast absorption of the heat of fusion. A significant, rapid temperature drop (100-500 K, even below melting temperature) at the very end of melting is revealed, which is caused by the collision of two finite-width interfaces and accelerated melting in about the 5 nm zone. For Q = 25-84 K ps(-1), standing elastic stress waves are observed in a solid with nodal points at the moving solid-melt interfaces, which, however, do not have a profound effect on melting time or temperatures. When surface melting is suppressed, barrierless bulk melting occurs in the entire sample, and elastodynamic effects are more important. Good correspondence with published, experimentally-determined melting time is found for a broad range of heating rates. Similar approaches can be applied to study various phase transformations in different materials and nanostructures under high heating rates. PMID:26561920

  12. Are All Obsidians Super-Heated? Insights from Observations of Crystallization Kinetics in Experiments on Glass Mountain Obsidians (Long Valley, CA)

    NASA Astrophysics Data System (ADS)

    Waters, L.; Andrews, B. J.

    2015-12-01

    The Glass Mountain obsidians (Long Valley, CA) are crystal-poor (<8%) and highly-evolved (high SiO2, low MgO, Sr, Ba) and, therefore, their formation required extremely efficient crystal-liquid separation. Petrologic and experimental investigation of the mineral phases in Glass Mountain lavas may reveal differentiation processes that generated the obsidians, if the mineral assemblage is phenocrystic. Results of high-resolution SEM mapping and electron microprobe analysis of a Glass Mountain sample reveal that the obsidian is saturated in nine phases (sanidine + quartz + plagioclase + ilmenite + titanomagnetite + zircon + apatite + allanite + biotite). Sanidine (Or78-Or35) and quartz occur in the largest abundances, and plagioclase (super-heated prior to crystallization, achieved either by fluid under-saturated decompression from a crystalline mush or H2O-saturated partial melting.

  13. Nuclear Medicine

    MedlinePlus

    ... Parents/Teachers Resource Links for Students Glossary Nuclear Medicine What is nuclear medicine? What are radioactive tracers? ... funded researchers advancing nuclear medicine? What is nuclear medicine? Nuclear medicine is a medical specialty that uses ...

  14. A physical zero-knowledge object-comparison system for nuclear warhead verification

    PubMed Central

    Philippe, Sébastien; Goldston, Robert J.; Glaser, Alexander; d'Errico, Francesco

    2016-01-01

    Zero-knowledge proofs are mathematical cryptographic methods to demonstrate the validity of a claim while providing no further information beyond the claim itself. The possibility of using such proofs to process classified and other sensitive physical data has attracted attention, especially in the field of nuclear arms control. Here we demonstrate a non-electronic fast neutron differential radiography technique using superheated emulsion detectors that can confirm that two objects are identical without revealing their geometry or composition. Such a technique could form the basis of a verification system that could confirm the authenticity of nuclear weapons without sharing any secret design information. More broadly, by demonstrating a physical zero-knowledge proof that can compare physical properties of objects, this experiment opens the door to developing other such secure proof-systems for other applications. PMID:27649477

  15. A physical zero-knowledge object-comparison system for nuclear warhead verification

    NASA Astrophysics Data System (ADS)

    Philippe, Sébastien; Goldston, Robert J.; Glaser, Alexander; D'Errico, Francesco

    2016-09-01

    Zero-knowledge proofs are mathematical cryptographic methods to demonstrate the validity of a claim while providing no further information beyond the claim itself. The possibility of using such proofs to process classified and other sensitive physical data has attracted attention, especially in the field of nuclear arms control. Here we demonstrate a non-electronic fast neutron differential radiography technique using superheated emulsion detectors that can confirm that two objects are identical without revealing their geometry or composition. Such a technique could form the basis of a verification system that could confirm the authenticity of nuclear weapons without sharing any secret design information. More broadly, by demonstrating a physical zero-knowledge proof that can compare physical properties of objects, this experiment opens the door to developing other such secure proof-systems for other applications.

  16. A physical zero-knowledge object-comparison system for nuclear warhead verification.

    PubMed

    Philippe, Sébastien; Goldston, Robert J; Glaser, Alexander; d'Errico, Francesco

    2016-09-20

    Zero-knowledge proofs are mathematical cryptographic methods to demonstrate the validity of a claim while providing no further information beyond the claim itself. The possibility of using such proofs to process classified and other sensitive physical data has attracted attention, especially in the field of nuclear arms control. Here we demonstrate a non-electronic fast neutron differential radiography technique using superheated emulsion detectors that can confirm that two objects are identical without revealing their geometry or composition. Such a technique could form the basis of a verification system that could confirm the authenticity of nuclear weapons without sharing any secret design information. More broadly, by demonstrating a physical zero-knowledge proof that can compare physical properties of objects, this experiment opens the door to developing other such secure proof-systems for other applications.

  17. A physical zero-knowledge object-comparison system for nuclear warhead verification.

    PubMed

    Philippe, Sébastien; Goldston, Robert J; Glaser, Alexander; d'Errico, Francesco

    2016-01-01

    Zero-knowledge proofs are mathematical cryptographic methods to demonstrate the validity of a claim while providing no further information beyond the claim itself. The possibility of using such proofs to process classified and other sensitive physical data has attracted attention, especially in the field of nuclear arms control. Here we demonstrate a non-electronic fast neutron differential radiography technique using superheated emulsion detectors that can confirm that two objects are identical without revealing their geometry or composition. Such a technique could form the basis of a verification system that could confirm the authenticity of nuclear weapons without sharing any secret design information. More broadly, by demonstrating a physical zero-knowledge proof that can compare physical properties of objects, this experiment opens the door to developing other such secure proof-systems for other applications. PMID:27649477

  18. Drop Impact on Superheated Surfaces

    NASA Astrophysics Data System (ADS)

    Tran, Tuan; Staat, Hendrik J. J.; Prosperetti, Andrea; Sun, Chao; Lohse, Detlef

    2012-01-01

    At the impact of a liquid droplet on a smooth surface heated above the liquid’s boiling point, the droplet either immediately boils when it contacts the surface (“contact boiling”), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (“gentle film boiling”), or both forms the Leidenfrost layer and ejects tiny droplets upward (“spraying film boiling”). We experimentally determine conditions under which impact behaviors in each regime can be realized. We show that the dimensionless maximum spreading γ of impacting droplets on the heated surfaces in both gentle and spraying film boiling regimes shows a universal scaling with the Weber number We (γ˜We2/5), which is much steeper than for the impact on nonheated (hydrophilic or hydrophobic) surfaces (γ˜We1/4). We also interferometrically measure the vapor thickness under the droplet.

  19. Nuclear rights - nuclear wrongs

    SciTech Connect

    Paul, E.F.; Miller, F.D.; Paul, J.; Ahrens, J.

    1986-01-01

    This book contains 11 selections. The titles are: Three Ways to Kill Innocent Bystanders: Some Conundrums Concerning the Morality of War; The International Defense of Liberty; Two Concepts of Deterrence; Nuclear Deterrence and Arms Control; Ethical Issues for the 1980s; The Moral Status of Nuclear Deterrent Threats; Optimal Deterrence; Morality and Paradoxical Deterrence; Immoral Risks: A Deontological Critique of Nuclear Deterrence; No War Without Dictatorship, No Peace Without Democracy: Foreign Policy as Domestic Politics; Marxism-Leninism and its Strategic Implications for the United States; Tocqueveille War.

  20. Modeling and Testing of Non-Nuclear, Highpower Simulated Nuclear Thermal Rocket Reactor Elements

    NASA Technical Reports Server (NTRS)

    Kirk, Daniel R.

    2005-01-01

    When the President offered his new vision for space exploration in January of 2004, he said, "Our third goal is to return to the moon by 2020, as the launching point for missions beyond," and, "With the experience and knowledge gained on the moon, we will then be ready to take the next steps of space exploration: human missions to Mars and to worlds beyond." A human mission to Mars implies the need to move large payloads as rapidly as possible, in an efficient and cost-effective manner. Furthermore, with the scientific advancements possible with Project Prometheus and its Jupiter Icy Moons Orbiter (JIMO), (these use electric propulsion), there is a renewed interest in deep space exploration propulsion systems. According to many mission analyses, nuclear thermal propulsion (NTP), with its relatively high thrust and high specific impulse, is a serious candidate for such missions. Nuclear rockets utilize fission energy to heat a reactor core to very high temperatures. Hydrogen gas flowing through the core then becomes superheated and exits the engine at very high exhaust velocities. The combination of temperature and low molecular weight results in an engine with specific impulses above 900 seconds. This is almost twice the performance of the LOX/LH2 space shuttle engines, and the impact of this performance would be to reduce the trip time of a manned Mars mission from the 2.5 years, possible with chemical engines, to about 12-14 months.

  1. Physics with gamma-beams and charged particle detectors: I) Nuclear structure II) Nuclear astrophysics

    SciTech Connect

    Gai, Moshe

    2015-02-24

    The Charged Particle Working Group (CPWG) is proposing to construct large area Silicon Strip Detector (SSD), a gas Time Projection Chamber detector read by an electronic readout system (eTPC) and a Bubble Chamber (BC) containing superheated high purity water to be used in measurements utilizing intense gamma-ray beams from the newly constructed ELI-NP facility at Magurele, Bucharest in Romania. We intend to use the SSD and eTPC detectors to address essential problems in nuclear structure physics, such as clustering and the many alpha-decay of light nuclei such as {sup 12}C and {sup 16}O. All three detectors (SSD, eTPC and BC) will be used to address central problems in nuclear astrophysics such as the astrophysical cross section factor of the {sup 12}C(α,γ) reaction and other processes central to stellar evolution. The CPWG intends to submit to the ELI-NP facility a Technical Design Report (TDR) for the proposed detectors.

  2. Physics with gamma-beams and charged particle detectors: I) Nuclear structure II) Nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Gai, Moshe

    2015-02-01

    The Charged Particle Working Group (CPWG) is proposing to construct large area Silicon Strip Detector (SSD), a gas Time Projection Chamber detector read by an electronic readout system (eTPC) and a Bubble Chamber (BC) containing superheated high purity water to be used in measurements utilizing intense gamma-ray beams from the newly constructed ELI-NP facility at Magurele, Bucharest in Romania. We intend to use the SSD and eTPC detectors to address essential problems in nuclear structure physics, such as clustering and the many alpha-decay of light nuclei such as 12C and 16O . All three detectors (SSD, eTPC and BC) will be used to address central problems in nuclear astrophysics such as the astrophysical cross section factor of the 12C (α,γ) reaction and other processes central to stellar evolution. The CPWG intends to submit to the ELI-NP facility a Technical Design Report (TDR) for the proposed detectors.

  3. Nuclear ventriculography

    MedlinePlus

    ... ventriculography (RNV); Multiple gate acquisition scan (MUGA); Nuclear cardiology; Cardiomyopathy - nuclear ventriculography ... 56. Udelson JE, Dilsizian V, Bonow RO. Nuclear cardiology. In: Bonow RO, Mann DL, Zipes DP, Libby ...

  4. Nuclear Medicine.

    ERIC Educational Resources Information Center

    Badawi, Ramsey D.

    2001-01-01

    Describes the use of nuclear medicine techniques in diagnosis and therapy. Describes instrumentation in diagnostic nuclear medicine and predicts future trends in nuclear medicine imaging technology. (Author/MM)

  5. Nuclear weapons and nuclear war

    SciTech Connect

    Cassel, C.; McCally, M.; Abraham, H.

    1984-01-01

    This book examines the potential radiation hazards and environmental impacts of nuclear weapons. Topics considered include medical responsibility and thermonuclear war, the threat of nuclear war, nuclear weaponry, biological effects, radiation injury, decontamination, long-term effects, ecological effects, psychological aspects, the economic implications of nuclear weapons and war, ethics, civil defense, arms control, nuclear winter, and long-term biological consequences of nuclear war.

  6. Nuclear Theory - Nuclear Power

    NASA Astrophysics Data System (ADS)

    Svenne, J. P.; Canton, L.; Kozier, K. S.

    2008-01-01

    The results from modern nuclear theory are accurate and reliable enough to be used for practical applications, in particular for scattering that involves few-nucleon systems of importance to nuclear power. Using well-established nucleon-nucleon (NN) interactions that fit well the NN scattering data, and the AGS form of the three-body theory, we have performed precise calculations of low-energy neutron-deuteron (n+d) scattering. We show that three-nucleon force effects that have impact on the low-energy vector analyzing powers have no practical effects on the angular distribution of the n+d cross-section. There appear to be problems for this scattering in the evaluated nuclear data file (ENDF) libraries, at the incident neutron energies less than 3.2 MeV. Supporting experimental data in this energy region are rather old (>25 years), sparse and often inconsistent. Our three-body results at low energies, 50 keV to 10.0 MeV, are compared to the ENDF/B-VII.0 and JENDL (Japanese Evaluated Nuclear Data Library) -3.3 evaluated angular distributions. The impact of these results on the calculated reactivity for various critical systems involving heavy water is shown.

  7. Nuclear choices

    SciTech Connect

    Wolfson, R.

    1991-01-01

    This book contains part of the series New Liberal Arts, which is intended to make science and technology more accessible to students of the liberal arts. Volume in hand provides a comprehensive, multifaceted examination of nuclear energy, in nontechnical terms. Wolfson explains the basics of nuclear energy and radiation, nuclear power..., and nuclear weapons..., and he invites readers to make their own judgments on controversial nuclear issues. Illustrated with photos and diagrams. Each chapter contains suggestions for additional reading and a glossary. For policy, science, and general collections in all libraries. (ES) Topics contained include Atoms and nuclei. Effects and uses of radiation. Energy and People. Reactor safety. Nuclear strategy. Defense in the nuclear age. Nuclear power, nuclear weapons, and nuclear futures.

  8. Development of bubble chambers with enhanced stability and sensitivity to low-energy nuclear recoils

    SciTech Connect

    Bolte, W.J.; Collar, Juan I.; Crisler, M.; Hall, J.; Holmgren, D.; Nakazawa, D.; Odom, B.; O'Sullivan, K.; Plunkett, R.; Ramberg, E.; Raskin, A.; Sonnenschein, A.; Vieira, J.D.; /Chicago U., EFI /KICP, Chicago /Fermilab

    2005-03-01

    The viability of using a Bubble Chamber for rare event searches and in particular for the detection of dark matter particle candidates is considered. Techniques leading to the deactivation of inhomogeneous nucleation centers and subsequent enhanced stability in such a detector are described. Results from prototype trials indicate that sensitivity to low-energy nuclear recoils like those expected from Weakly Interacting Massive Particles can be obtained in conditions of near total insensitivity to minimum ionizing backgrounds. An understanding of the response of superheated heavy refrigerants to these recoils is demonstrated within the context of existing theoretical models. We comment on the prospects for the detection of supersymmetric dark matter particles with a large CF{sub 3}I chamber.

  9. Nuclear Winter.

    ERIC Educational Resources Information Center

    Ehrlich, Anne

    1984-01-01

    "Nuclear Winter" was recently coined to describe the climatic and biological effects of a nuclear war. These effects are discussed based on models, simulations, scenarios, and projections. Effects on human populations are also considered. (JN)

  10. Nuclear Chemistry.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1979

    1979-01-01

    Provides a brief review of the latest developments in nuclear chemistry. Nuclear research today is directed toward increased activity in radiopharmaceuticals and formation of new isotopes by high-energy, heavy-ion collisions. (Author/BB)

  11. Nuclear Scans

    MedlinePlus

    Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

  12. Nuclear Fuels.

    ERIC Educational Resources Information Center

    Nash, J. Thomas

    1983-01-01

    Trends in and factors related to the nuclear industry and nuclear fuel production are discussed. Topics addressed include nuclear reactors, survival of the U.S. uranium industry, production costs, budget cuts by the Department of Energy and U.S. Geological survey for resource studies, mining, and research/development activities. (JN)

  13. Nuclear weapons, nuclear effects, nuclear war

    SciTech Connect

    Bing, G.F.

    1991-08-20

    This paper provides a brief and mostly non-technical description of the militarily important features of nuclear weapons, of the physical phenomena associated with individual explosions, and of the expected or possible results of the use of many weapons in a nuclear war. Most emphasis is on the effects of so-called ``strategic exchanges.``

  14. TH{_}PULSE: Program for Calculating Infiltration of Episodic Liquid Fingers in Superheated Rock Fractures - Theory, User's Manual and Sample Applications

    SciTech Connect

    Birkholzer, Jens T.

    2002-07-10

    This report describes the code TH{_}PULSE developed at the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab). The code handles gravity-driven flow of episodic infiltration events entering above-boiling rock-temperature regions. Such temperature conditions are expected, for example, after emplacement of heat-generating nuclear waste in underground repositories. Complex fluid-flow and heat-transfer phenomena occur, as the infiltrating water is subject to vigorous boiling from the hot rock. A new efficient semi-analytical method is presented herein that simulates such phenomena. It is assumed that flow forms in localized preferential flow paths (referred to as ''fingers''). The first section of this report gives the conceptual and mathematical background for the solution scheme. The second section is a user's manual for TH{_}PULSE, providing all information required to run the code, including a detailed description of the input and output files. In the third section, the new solution scheme is applied to several test cases. Sample simulations are performed for conditions representative of the potential nuclear waste repository at Yucca Mountain, Nevada. A brief summary is given in Section 4.

  15. The Influence of Green Surface Modification of Oil Palm Mesocarp Fiber by Superheated Steam on the Mechanical Properties and Dimensional Stability of Oil Palm Mesocarp Fiber/Poly(butylene succinate) Biocomposite

    PubMed Central

    Then, Yoon Yee; Ibrahim, Nor Azowa; Zainuddin, Norhazlin; Ariffin, Hidayah; Yunus, Wan Md Zin Wan; Chieng, Buong Woei

    2014-01-01

    In this paper, superheated steam (SHS) was used as cost effective and green processing technique to modify oil palm mesocarp fiber (OPMF) for biocomposite applications. The purpose of this modification was to promote the adhesion between fiber and thermoplastic. The modification was carried out in a SHS oven at various temperature (200–230 °C) and time (30–120 min) under normal atmospheric pressure. The biocomposites from SHS-treated OPMFs and poly(butylene succinate) (PBS) at a weight ratio of 70:30 were prepared by melt blending technique. The mechanical properties and dimensional stability of the biocomposites were evaluated. This study showed that the SHS treatment increased the roughness of the fiber surface due to the removal of surface impurities and hemicellulose. The tensile, flexural and impact properties, as well as dimensional stability of the biocomposites were markedly enhanced by the presence of SHS-treated OPMF. Scanning electron microscopy analysis showed improvement of interfacial adhesion between PBS and SHS-treated OPMF. This work demonstrated that SHS could be used as an eco-friendly and sustainable processing method for modification of OPMF in biocomposite fabrication. PMID:25177865

  16. The influence of green surface modification of oil palm mesocarp fiber by superheated steam on the mechanical properties and dimensional stability of oil palm mesocarp fiber/poly(butylene succinate) biocomposite.

    PubMed

    Then, Yoon Yee; Ibrahim, Nor Azowa; Zainuddin, Norhazlin; Ariffin, Hidayah; Yunus, Wan Md Zin Wan; Chieng, Buong Woei

    2014-08-29

    In this paper, superheated steam (SHS) was used as cost effective and green processing technique to modify oil palm mesocarp fiber (OPMF) for biocomposite applications. The purpose of this modification was to promote the adhesion between fiber and thermoplastic. The modification was carried out in a SHS oven at various temperature (200-230 °C) and time (30-120 min) under normal atmospheric pressure. The biocomposites from SHS-treated OPMFs and poly(butylene succinate) (PBS) at a weight ratio of 70:30 were prepared by melt blending technique. The mechanical properties and dimensional stability of the biocomposites were evaluated. This study showed that the SHS treatment increased the roughness of the fiber surface due to the removal of surface impurities and hemicellulose. The tensile, flexural and impact properties, as well as dimensional stability of the biocomposites were markedly enhanced by the presence of SHS-treated OPMF. Scanning electron microscopy analysis showed improvement of interfacial adhesion between PBS and SHS-treated OPMF. This work demonstrated that SHS could be used as an eco-friendly and sustainable processing method for modification of OPMF in biocomposite fabrication.

  17. Nuclear mortality

    SciTech Connect

    Krauthammer, C.

    1983-10-01

    The author notes that the anti-nuclear movement is shifting its focus from bodily harm to concern for the impact on our souls from building and threatening the use of nuclear weapons. Two aspects of nuclear deterrence receiving the most public attention are the freeze effort to halt weapons modernization and the no-first-use effort to take down the nuclear umbrella. Opponents attack both the countervalue and the counterforce approach, but the arguments of the Catholic bishops, Jonathan Schell, and others stop short of unilateral disarmament, which would be the greatest threat to our survival. Mr. Krauthammer observes that nuclear deterrence has worked, however, and will continue to be useful only if potential adversaries believe we have the will to use nuclear weapons. 2 references. (DCK)

  18. Nuclear astrophysics

    SciTech Connect

    Haxton, W.C.

    1992-01-01

    The problem of core-collapse supernovae is used to illustrate the many connections between nuclear astrophysics and the problems nuclear physicists study in terrestrial laboratories. Efforts to better understand the collapse and mantle ejection are also motivated by a variety of interdisciplinary issues in nuclear, particle, and astrophysics, including galactic chemical evolution, neutrino masses and mixing, and stellar cooling by the emission of new particles. The current status of theory and observations is summarized.

  19. Nuclear astrophysics

    SciTech Connect

    Haxton, W.C.

    1992-12-31

    The problem of core-collapse supernovae is used to illustrate the many connections between nuclear astrophysics and the problems nuclear physicists study in terrestrial laboratories. Efforts to better understand the collapse and mantle ejection are also motivated by a variety of interdisciplinary issues in nuclear, particle, and astrophysics, including galactic chemical evolution, neutrino masses and mixing, and stellar cooling by the emission of new particles. The current status of theory and observations is summarized.

  20. Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Drago, Alessandro

    2005-04-01

    The activity of the Italian nuclear physicists community in the field of Nuclear Astrophysics is reported. The researches here described have been performed within the project "Fisica teorica del nucleo e dei sistemi a multi corpi", supported by the Ministero dell'Istruzione, dell'Università e della Ricerca.

  1. Nuclear safety

    NASA Technical Reports Server (NTRS)

    Buden, D.

    1991-01-01

    Topics dealing with nuclear safety are addressed which include the following: general safety requirements; safety design requirements; terrestrial safety; SP-100 Flight System key safety requirements; potential mission accidents and hazards; key safety features; ground operations; launch operations; flight operations; disposal; safety concerns; licensing; the nuclear engine for rocket vehicle application (NERVA) design philosophy; the NERVA flight safety program; and the NERVA safety plan.

  2. Nuclear hostages

    SciTech Connect

    O'Keefe, B.J.

    1983-01-01

    Classical physics since Roentgen's discovery of X-rays led quickly to work on atomic structure and the Nuclear Age. The author traces the history of decisions to pursue nuclear fission, the organization of the Manhattan Project, the compromises of the 1963 test ban treaty, and the dilemma of nuclear weapons development and deployment that now hold mankind hostage. He reviews the rationale for limited nuclear war, first strike, massive retaliation, non-proliferation, and the Strategic Arms Limitation Talks (SALT) treaties. He argues that the concepts of mobile MX weapons, fratricide, and population dispersal for civil defense are unworkable, suggesting a program of unilaterally withdrawing tactical nuclear weapons from Europe and strengthening intelligence and law-enforcement powers to withstand terrorist activity. Economic cooperation and political reconciliation may take a generation to achieve, but should be our national goal.

  3. Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Bombaci, Ignazio

    2003-04-01

    In this report I will try to illustrate some of the main research themes and "hot topics" in nuclear astrophysics. The particular aim of the present report is to briefly illustrate the research activities, in the field of nuclear astrophysics, performed by the Italian nuclear physicist community within the "Programma di Interesse Nazionale su Fisica Teorica del Nucleo e dei Sistemi a Molti Corpi" (National Research Program on Theoretical Physics of Nuclei and Many Body Systems) supported by the "Ministero dell'Istruzione dell'Università e della Ricerca".

  4. Nuclear Speckles

    PubMed Central

    Spector, David L.; Lamond, Angus I.

    2011-01-01

    Nuclear speckles, also known as interchromatin granule clusters, are nuclear domains enriched in pre-mRNA splicing factors, located in the interchromatin regions of the nucleoplasm of mammalian cells. When observed by immunofluorescence microscopy, they usually appear as 20–50 irregularly shaped structures that vary in size. Speckles are dynamic structures, and their constituents can exchange continuously with the nucleoplasm and other nuclear locations, including active transcription sites. Studies on the composition, structure, and dynamics of speckles have provided an important paradigm for understanding the functional organization of the nucleus and the dynamics of the gene expression machinery. PMID:20926517

  5. (Nuclear theory). [Research in nuclear physics

    SciTech Connect

    Haxton, W.

    1990-01-01

    This report discusses research in nuclear physics. Topics covered in this paper are: symmetry principles; nuclear astrophysics; nuclear structure; quark-gluon plasma; quantum chromodynamics; symmetry breaking; nuclear deformation; and cold fusion. (LSP)

  6. Nuclear forces

    SciTech Connect

    Machleidt, R.

    2013-06-10

    These lectures present an introduction into the theory of nuclear forces. We focus mainly on the modern approach, in which the forces between nucleons emerge from low-energy QCD via chiral effective field theory.

  7. Nuclear Disarmament.

    ERIC Educational Resources Information Center

    Johnson, Christopher

    1982-01-01

    Material about nuclear disarmament and the arms race should be included in secondary school curricula. Teachers can present this technical, controversial, and frightening material in a balanced and comprehensible way. Resources for instructional materials are listed. (PP)

  8. Nuclear battlefields

    SciTech Connect

    Arkin, W.M.; Fieldhouse, R.W.

    1985-01-01

    This book provides complete data on the nuclear operations and research facilities in the U.S.A., the U.S.S.R., France, China and the U.K. It describes detailed estimates on the U.S.S.R.'s nuclear stockpile for over 500 locations. It shows how non-nuclear countries cooperate with the world-wide war machine. And it maps the U.S. nuclear facilities from Little America, WY, and Charleston, SC, to the battleships patroling the world's oceans and subs stalking under the sea. The data were gathered from unclassified sources through the Freedom of Information Act, from data supplied to military installations, and from weapons source books. It provides guidance for policymakers, government and corporate officials.

  9. NUCLEAR REACTOR

    DOEpatents

    Sherman, J.; Sharbaugh, J.E.; Fauth, W.L. Jr.; Palladino, N.J.; DeHuff, P.G.

    1962-10-23

    A nuclear reactor incorporating seed and blanket assemblies is designed. Means are provided for obtaining samples of the coolant from the blanket assemblies and for varying the flow of coolant through the blanket assemblies. (AEC)

  10. Nuclear Data

    SciTech Connect

    White, Morgan C.

    2014-01-23

    PowerPoint presentation targeted for educational use. Nuclear data comes from a variety of sources and in many flavors. Understanding where the data you use comes from and what flavor it is can be essential to understand and interpret your results. This talk will discuss the nuclear data pipeline with particular emphasis on providing links to additional resources that can be used to explore the issues you will encounter.

  11. Nuclear Nonproliferation

    SciTech Connect

    Atkins-Duffin, C E

    2008-12-10

    With an explosion equivalent of about 20kT of TNT, the Trinity test was the first demonstration of a nuclear weapon. Conducted on July 16, 1945 in Alamogordo, NM this site is now a Registered National Historic Landmark. The concept and applicability of nuclear power was demonstrated on December 20, 1951 with the Experimental Breeder Reactor Number One (EBR-1) lit four light bulbs. This reactor is now a Registered National Historic Landmark, located near Arco, ID. From that moment forward it had been clearly demonstrated that nuclear energy has both peaceful and military applications and that the civilian and military fuel cycles can overlap. For the more than fifty years since the Atoms for Peace program, a key objective of nuclear policy has been to enable the wider peaceful use of nuclear energy while preventing the spread of nuclear weapons. Volumes have been written on the impact of these two actions on the world by advocates and critics; pundits and practioners; politicians and technologists. The nations of the world have woven together a delicate balance of treaties, agreements, frameworks and handshakes that are representative of the timeframe in which they were constructed and how they have evolved in time. Collectively these vehicles attempt to keep political will, nuclear materials and technology in check. This paper captures only the briefest abstract of the more significant aspects on the Nonproliferation Regime. Of particular relevance to this discussion is the special nonproliferation sensitivity associated with the uranium isotope separation and spent fuel reprocessing aspects of the nuclear fuel cycle.

  12. Nuclear Structure

    NASA Astrophysics Data System (ADS)

    Gargano, Angela

    2003-04-01

    An account of recent studies in the field of theoretical nuclear structure is reported. These studies concern essentially research activities performed under the Italian project "Fisica Teorica del Nucleo e dei Sistemi a Molti Corpi". Special attention is addressed to results obtained during the last two years as regards the development of new many-body techniques as well as the interpretation of new experimental aspects of nuclear structure.

  13. Nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Arnould, M.; Takahashi, K.

    1999-03-01

    Nuclear astrophysics is that branch of astrophysics which helps understanding of the Universe, or at least some of its many faces, through the knowledge of the microcosm of the atomic nucleus. It attempts to find as many nuclear physics imprints as possible in the macrocosm, and to decipher what those messages are telling us about the varied constituent objects in the Universe at present and in the past. In the last decades much advance has been made in nuclear astrophysics thanks to the sometimes spectacular progress made in the modelling of the structure and evolution of the stars, in the quality and diversity of the astronomical observations, as well as in the experimental and theoretical understanding of the atomic nucleus and of its spontaneous or induced transformations. Developments in other subfields of physics and chemistry have also contributed to that advance. Notwithstanding the accomplishment, many long-standing problems remain to be solved, and the theoretical understanding of a large variety of observational facts needs to be put on safer grounds. In addition, new questions are continuously emerging, and new facts endangering old ideas. This review shows that astrophysics has been, and still is, highly demanding to nuclear physics in both its experimental and theoretical components. On top of the fact that large varieties of nuclei have to be dealt with, these nuclei are immersed in highly unusual environments which may have a significant impact on their static properties, the diversity of their transmutation modes, and on the probabilities of these modes. In order to have a chance of solving some of the problems nuclear astrophysics is facing, the astrophysicists and nuclear physicists are obviously bound to put their competence in common, and have sometimes to benefit from the help of other fields of physics, like particle physics, plasma physics or solid-state physics. Given the highly varied and complex aspects, we pick here some specific nuclear

  14. Nuclear telemedicine

    NASA Astrophysics Data System (ADS)

    Morrison, R. T.; Szasz, I. J.

    1990-06-01

    Diagnostic nuclear medicine patient images have been transniitted for 8 years from a regional conununity hospital to a university teaching hospital 700 kiloinetres away employing slow scan TV and telephone. Transruission and interpretation were done at the end of each working day or as circumstances required in cases of emergencies. Referring physicians received the nuclear medicine procedure report at the end of the completion day or within few minutes of completion in case of emergency procedures. To date more than 25 patient studies have been transmitted for interpretation. Blinded reinterpretation of the original hard copy data of 350 patient studies resulted in 100 agreement with the interpretation of transmitted data. This technique provides high quality diagnostic and therapeutic nuclear medicine services in remote hospitals where the services of an on-site nuclear physician is not available. 2. HISTORY Eight years ago when the nuclear medicine physician at Trail Regional Hospital left the Trail area and an other could not be recruited we examined the feasibility of image transmission by phone for interpretation since closing the department would have imposed unacceptable physical and financial hardship and medical constraints on the patient population the nearest nuclear medicine facility was at some 8 hours drive away. In hospital patients would have to be treated either based purely on physical findings or flown to Vancouver at considerable cost to the health care system (estimated cost $1500.

  15. Nuclear waste

    SciTech Connect

    Not Available

    1988-05-01

    This paper discusses how, as part of the Department of Energy's implementation of the Nuclear Waste Policy Act of 1982, DOE is required to investigate a site at Yucca Mountain, Nevada and, if it determines that the site is suitable, recommend to the President its selection for a nuclear waste repository. The Nuclear Regulatory Commission, in considering development of the plan, issued five objections, one of which is DOE's failure to recognize the range of alternative conceptual models of the Yucca Mountain site that can be supported by the limited existing technical data. At the end of the quarter DOE directed its project offices in Washington and Texas to begin orderly phase-out of all site-specific repository activities. Costs for this phase-out are $53 million for the Deaf Smith site and $85 million for the Hanford site.

  16. Nuclear scales

    SciTech Connect

    Friar, J.L.

    1998-12-01

    Nuclear scales are discussed from the nuclear physics viewpoint. The conventional nuclear potential is characterized as a black box that interpolates nucleon-nucleon (NN) data, while being constrained by the best possible theoretical input. The latter consists of the longer-range parts of the NN force (e.g., OPEP, TPEP, the {pi}-{gamma} force), which can be calculated using chiral perturbation theory and gauged using modern phase-shift analyses. The shorter-range parts of the force are effectively parameterized by moments of the interaction that are independent of the details of the force model, in analogy to chiral perturbation theory. Results of GFMC calculations in light nuclei are interpreted in terms of fundamental scales, which are in good agreement with expectations from chiral effective field theories. Problems with spin-orbit-type observables are noted.

  17. Nuclear pursuits

    SciTech Connect

    Not Available

    1993-05-01

    This table lists quantities of warheads (in stockpile, peak number per year, total number built, number of known test explosions), weapon development milestones (developers of the atomic bomb and hydrogen bomb, date of first operational ICBM, first nuclear-powered naval SSN in service, first MIRVed missile deployed), and testing milestones (first fission test, type of boosted fission weapon, multistage thermonuclear test, number of months from fission bomb to multistage thermonuclear bomb, etc.), and nuclear infrastructure (assembly plants, plutonium production reactors, uranium enrichment plants, etc.). Countries included in the tally are the United States, Soviet Union, Britain, France, and China.

  18. Nuclear power: Fourth edition

    SciTech Connect

    Deutsch, R.W.

    1986-01-01

    This book describes the basics of nuclear power generation, explaining both the benefits and the real and imagined risks of nuclear power. It includes a discussion of the Three Mile Island accident and its effects. Nuclear Power has been used in the public information programs of more than 100 utilities. The contents discussed are: Nuclear Power and People; Why Nuclear Power. Electricity produced by coal; Electricity produced by nuclear fuel; Nuclear plant sites in the United States; Short History of Commercial Nuclear Power; U.S. nuclear submarines, Regulation of Nuclear Power Plants; Licensing process, Nuclear Power Plant Operator Training; Nuclear power plant simulator, Are Nuclear Plants Safe.; Containment structure, Nuclear Power Plant Insurance; Is Radiation Dangerous.; Man-made radiation, What is Nuclear Fuel.; Fuel cycle for commercial nuclear power plants; Warm Water Discharge; Cooling tower; Protection of Radioactive Materials; Plutonium and Proliferation; Disposal of Radioactive Wastes; Are Alternate Energy Sources Available.; Nuclear Opposition; and Nuclear Power in the Future.

  19. Nuclear medicine

    SciTech Connect

    Wagner, H.N. Jr.

    1986-10-17

    In 1985 and 1986 nuclear medicine became more and more oriented toward in vov chemistry, chiefly as a result of advances in positron emission tomography (PET). The most important trend was the extension of PET technology into the care of patients with brain tumors, epilepsy, and heart disease. A second trend was the increasing use of single-photon emission computed tomography (SPECT).

  20. NUCLEAR REACTOR

    DOEpatents

    Treshow, M.

    1961-09-01

    A boiling-water nuclear reactor is described wherein control is effected by varying the moderator-to-fuel ratio in the reactor core. This is accomplished by providing control tubes containing a liquid control moderator in the reactor core and providing means for varying the amount of control moderatcr within the control tubes.

  1. Nuclear Science.

    ERIC Educational Resources Information Center

    Pennsylvania State Dept. of Education, Harrisburg. Bureau of Curriculum Services.

    This document is a report on a course in nuclear science for the high school curriculum. The course is designed to provide a basic but comprehensive understanding of the atom in the light of modern knowledge, and to show how people attempt to harness the tremendous energy liberated through fission and fusion reactions. The course crosses what are…

  2. Nuclear Misinformation

    ERIC Educational Resources Information Center

    Ford, Daniel F.; Kendall, Henry W.

    1975-01-01

    Many scientists feel that research into nuclear safety has been diverted or distorted, and the results of the research concealed or inaccurately reported on a large number of occasions. Of particular concern have been the emergency cooling systems which have not, as yet, been adequately tested. (Author/MA)

  3. Nuclear explosions

    SciTech Connect

    Broyles, A.A.

    1982-07-01

    A summary of the physics of a nuclear bomb explosion and its effects on human beings is presented at the level of a sophomore general physics course without calculus. It is designed to supplement a standard text for such a course and problems are included.

  4. Nuclear energy.

    PubMed

    Wilson, Peter D

    2010-01-01

    The technical principles and practices of the civil nuclear industry are described with particular reference to fission and its products, natural and artificial radioactivity elements principally concerned and their relationships, main types of reactor, safety issues, the fuel cycle, waste management, issues related to weapon proliferation, environmental considerations and possible future developments.

  5. Nuclear Terrorism.

    SciTech Connect

    Hecker, Siegfried S.

    2001-01-01

    As pointed out by several speakers, the level of violence and destruction in terrorist attacks has increased significantly during the past decade. Fortunately, few have involved weapons of mass destruction, and none have achieved mass casualties. The Aum Shinrikyo release of lethal nerve agent, sarin, in the Tokyo subway on March 20, 1995 clearly broke new ground by crossing the threshold in attempting mass casualties with chemical weapons. However, of all weapons of mass destruction, nuclear weapons still represent the most frightening threat to humankind. Nuclear weapons possess an enormous destructive force. The immediacy and scale of destruction are unmatched. In addition to destruction, terrorism also aims to create fear among the public and governments. Here also, nuclear weapons are unmatched. The public's fear of nuclear weapons or, for that matter, of all radioactivity is intense. To some extent, this fear arises from a sense of unlimited vulnerability. That is, radioactivity is seen as unbounded in three dimensions - distance, it is viewed as having unlimited reach; quantity, it is viewed as having deadly consequences in the smallest doses (the public is often told - incorrectly, of course - that one atom of plutonium will kill); and time, if it does not kill you immediately, then it will cause cancer decades hence.

  6. Explosive cavitation in superheated liquid argon.

    PubMed

    Vinogradov, V E; Pavlov, P A; Baidakov, V G

    2008-06-21

    The kinetics of explosive boiling-up of liquid argon has been investigated at negative pressures created by the reflection of a compression pulse 3-5 mus long from the free surface of a liquid by the method of liquid pulse heating on a thin platinum wire (with a rate of temperature increase of about 1 Kmus). The limiting superheats T(*) (stretches p(*)), the effective nucleation rate J(*), and the derivative G(T)=(d ln JdT)(T=T(*) ) have been determined by experimental data on the thermal perturbation of a wire probe and the results of solution of the problem on the initial stage of explosive boiling-up of a liquid. The experimental data are compared with homogeneous nucleation theory. PMID:18570511

  7. Ultrafast electronic relaxation in superheated bismuth

    NASA Astrophysics Data System (ADS)

    Gamaly, E. G.; Rode, A. V.

    2013-01-01

    Interaction of moving electrons with vibrating ions in the lattice forms the basis for many physical properties from electrical resistivity and electronic heat capacity to superconductivity. In ultrafast laser interaction with matter the electrons are heated much faster than the electron-ion energy equilibration, leading to a two-temperature state with electron temperature far above that of the lattice. The rate of temperature equilibration is governed by the strength of electron-phonon energy coupling, which is conventionally described by a coupling constant, neglecting the dependence on the electron and lattice temperature. The application of this constant to the observations of fast relaxation rate led to a controversial notion of ‘ultra-fast non-thermal melting’ under extreme electronic excitation. Here we provide theoretical grounds for a strong dependence of the electron-phonon relaxation time on the lattice temperature. We show, by taking proper account of temperature dependence, that the heating and restructuring of the lattice occurs much faster than were predicted on the assumption of a constant, temperature independent energy coupling. We applied the temperature-dependent momentum and energy transfer time to experiments on fs-laser excited bismuth to demonstrate that all the observed ultra-fast transformations of the transient state of bismuth are purely thermal in nature. The developed theory, when applied to ultrafast experiments on bismuth, provides interpretation of the whole variety of transient phase relaxation without the non-thermal melting conjecture.

  8. Nuclear politics

    NASA Astrophysics Data System (ADS)

    Ranson, John

    2009-04-01

    The sentiments expressed by Sidney Drell in his forum article "The nuclear threat: a new start" (February pp16-17) are laudable, but it was disappointing to find this almost entirely political story in isolation. The article, which outlined the prospects for reducing weapons stockpiles under the new US administration, would have been more pertinent as an introduction to a series describing the technology used in detecting nuclear-testing activity. It would have been interesting to discuss the specific equipment and methods used, together with the analysis and correlation techniques - along with an indication of how sensitive and reliable they are (if the information is not classified). It is far easier to detect an explosive event than it is to detect and quantify weapons stores, which is a key factor for any negotiated solution. Apart from deductions based on actual inspection and satellite surveillance, are there other techniques that can be applied to this issue?

  9. NUCLEAR REACTORS

    DOEpatents

    Long, E.; Ashby, J.W.

    1958-09-16

    ABS>A graphite moderator structure is presented for a nuclear reactor compriscd of an assembly of similarly orientated prismatic graphite blocks arranged on spaced longitudinal axes lying in common planes wherein the planes of the walls of the blocks are positioned so as to be twisted reintive to the planes of said axes so thatthe unlmpeded dtrect paths in direction wholly across the walls of the blocks are limited to the width of the blocks plus spacing between the blocks.

  10. NUCLEAR REACTOR

    DOEpatents

    Anderson, C.R.

    1962-07-24

    A fluidized bed nuclear reactor and a method of operating such a reactor are described. In the design means are provided for flowing a liquid moderator upwardly through the center of a bed of pellets of a nentron-fissionable material at such a rate as to obtain particulate fluidization while constraining the lower pontion of the bed into a conical shape. A smooth circulation of particles rising in the center and falling at the outside of the bed is thereby established. (AEC)

  11. Nuclear Chirality

    SciTech Connect

    Starosta, Krzysztof

    2005-04-05

    Nuclear chirality is a novel manifestation of spontaneous symmetry breaking resulting from an orthogonal coupling of angular momentum vectors in triaxial nuclei. Three perpendicular angular momenta can form two systems of opposite handedness; the time reversal operator, which reverses orientation of each of the angular momentum components, relates these two systems. The status of current experimental searches for chiral doubling of states, as well as recent progress on the theoretical side is reviewed.

  12. Nuclear waste

    SciTech Connect

    Not Available

    1991-09-01

    Radioactive waste is mounting at U.S. nuclear power plants at a rate of more than 2,000 metric tons a year. Pursuant to statute and anticipating that a geologic repository would be available in 1998, the Department of Energy (DOE) entered into disposal contracts with nuclear utilities. Now, however, DOE does not expect the repository to be ready before 2010. For this reason, DOE does not want to develop a facility for monitored retrievable storage (MRS) by 1998. This book is concerned about how best to store the waste until a repository is available, congressional requesters asked GAO to review the alternatives of continued storage at utilities' reactor sites or transferring waste to an MRS facility, GAO assessed the likelihood of an MRSA facility operating by 1998, legal implications if DOE is not able to take delivery of wastes in 1998, propriety of using the Nuclear Waste Fund-from which DOE's waste program costs are paid-to pay utilities for on-site storage capacity added after 1998, ability of utilities to store their waste on-site until a repository is operating, and relative costs and safety of the two storage alternatives.

  13. Nuclear terrorism.

    PubMed

    Hogan, David E; Kellison, Ted

    2002-06-01

    Recent events have heightened awareness of the potential for terrorist attacks employing nonconventional weaponry such as biological agents and radiation. Historically, the philosophy of nuclear risk has focused on global or strategic nuclear exchanges and the resulting damage from large-scale releases. Currently, nuclear accidents or terrorist attacks involving low-level or regional release of radiation are considered the most likely events. Thus far, there have been several regional radiation incidents exposing hundreds of thousands of people to radiation, but there have been only a limited number of significant contaminations resulting in death. There are several different types of radioactive particles that differ in mass, extent of radiation emitted, and the degree to which tissue penetration occurs. Radiation affects its toxicity on biological systems by ionization, which creates tissue damage by the generation of free radicals, disruption of chemical bonds, and directly damaging cellular DNA and enzymes. The extent of damage depends on the type of radioisotope and the radiation dose. Radiation doses exceeding 2 to 10 Gy are considered lethal. Optimal management of radiation casualties requires knowledge of the type and dose of radiation received, a recognition of the manifestations of radiation sickness, and the use of standard medical care, decontamination, and decorporation techniques. PMID:12074488

  14. NUCLEAR REACTOR

    DOEpatents

    Grebe, J.J.

    1959-07-14

    High temperature reactors which are uniquely adapted to serve as the heat source for nuclear pcwered rockets are described. The reactor is comprised essentially of an outer tubular heat resistant casing which provides the main coolant passageway to and away from the reactor core within the casing and in which the working fluid is preferably hydrogen or helium gas which is permitted to vaporize from a liquid storage tank. The reactor core has a generally spherical shape formed entirely of an active material comprised of fissile material and a moderator material which serves as a diluent. The active material is fabricated as a gas permeable porous material and is interlaced in a random manner with very small inter-connecting bores or capillary tubes through which the coolant gas may flow. The entire reactor is divided into successive sections along the direction of the temperature gradient or coolant flow, each section utilizing materials of construction which are most advantageous from a nuclear standpoint and which at the same time can withstand the operating temperature of that particular zone. This design results in a nuclear reactor characterized simultaneously by a minimum critiral size and mass and by the ability to heat a working fluid to an extremely high temperature.

  15. Nuclear photonics

    SciTech Connect

    Habs, D.; Guenther, M. M.; Jentschel, M.; Thirolf, P. G.

    2012-07-09

    With the planned new {gamma}-beam facilities like MEGa-ray at LLNL (USA) or ELI-NP at Bucharest (Romania) with 10{sup 13}{gamma}/s and a band width of {Delta}E{gamma}/E{gamma} Almost-Equal-To 10{sup -3}, a new era of {gamma} beams with energies up to 20MeV comes into operation, compared to the present world-leading HI{gamma}S facility at Duke University (USA) with 10{sup 8}{gamma}/s and {Delta}E{gamma}/E{gamma} Almost-Equal-To 3 Dot-Operator 10{sup -2}. In the long run even a seeded quantum FEL for {gamma} beams may become possible, with much higher brilliance and spectral flux. At the same time new exciting possibilities open up for focused {gamma} beams. Here we describe a new experiment at the {gamma} beam of the ILL reactor (Grenoble, France), where we observed for the first time that the index of refraction for {gamma} beams is determined by virtual pair creation. Using a combination of refractive and reflective optics, efficient monochromators for {gamma} beams are being developed. Thus, we have to optimize the total system: the {gamma}-beam facility, the {gamma}-beam optics and {gamma} detectors. We can trade {gamma} intensity for band width, going down to {Delta}E{gamma}/E{gamma} Almost-Equal-To 10{sup -6} and address individual nuclear levels. The term 'nuclear photonics' stresses the importance of nuclear applications. We can address with {gamma}-beams individual nuclear isotopes and not just elements like with X-ray beams. Compared to X rays, {gamma} beams can penetrate much deeper into big samples like radioactive waste barrels, motors or batteries. We can perform tomography and microscopy studies by focusing down to {mu}m resolution using Nuclear Resonance Fluorescence (NRF) for detection with eV resolution and high spatial resolution at the same time. We discuss the dominating M1 and E1 excitations like the scissors mode, two-phonon quadrupole octupole excitations, pygmy dipole excitations or giant dipole excitations under the new facet of

  16. Nuclear photonics

    NASA Astrophysics Data System (ADS)

    Habs, D.; Günther, M. M.; Jentschel, M.; Thirolf, P. G.

    2012-07-01

    With the planned new γ-beam facilities like MEGa-ray at LLNL (USA) or ELI-NP at Bucharest (Romania) with 1013 γ/s and a band width of ΔEγ/Eγ≈10-3, a new era of γ beams with energies up to 20MeV comes into operation, compared to the present world-leading HIγS facility at Duke University (USA) with 108 γ/s and ΔEγ/Eγ≈3ṡ10-2. In the long run even a seeded quantum FEL for γ beams may become possible, with much higher brilliance and spectral flux. At the same time new exciting possibilities open up for focused γ beams. Here we describe a new experiment at the γ beam of the ILL reactor (Grenoble, France), where we observed for the first time that the index of refraction for γ beams is determined by virtual pair creation. Using a combination of refractive and reflective optics, efficient monochromators for γ beams are being developed. Thus, we have to optimize the total system: the γ-beam facility, the γ-beam optics and γ detectors. We can trade γ intensity for band width, going down to ΔEγ/Eγ≈10-6 and address individual nuclear levels. The term "nuclear photonics" stresses the importance of nuclear applications. We can address with γ-beams individual nuclear isotopes and not just elements like with X-ray beams. Compared to X rays, γ beams can penetrate much deeper into big samples like radioactive waste barrels, motors or batteries. We can perform tomography and microscopy studies by focusing down to μm resolution using Nuclear Resonance Fluorescence (NRF) for detection with eV resolution and high spatial resolution at the same time. We discuss the dominating M1 and E1 excitations like the scissors mode, two-phonon quadrupole octupole excitations, pygmy dipole excitations or giant dipole excitations under the new facet of applications. We find many new applications in biomedicine, green energy, radioactive waste management or homeland security. Also more brilliant secondary beams of neutrons and positrons can be produced.

  17. The Nuclear Power and Nuclear Weapons Connection.

    ERIC Educational Resources Information Center

    Leventhal, Paul

    1990-01-01

    Explains problems enforcing the Nuclear Non-Proliferation Treaty (NPT) of 1968. Provides factual charts and details concerning the production of nuclear energy and arms, the processing and disposal of waste products, and outlines the nuclear fuel cycle. Discusses safeguards, the risk of nuclear terrorism, and ways to deal with these problems. (NL)

  18. The nuclear arsenals and nuclear disarmament.

    PubMed

    Barnaby, F

    1998-01-01

    Current world stockpiles of nuclear weapons and the status of treaties for nuclear disarmament and the ultimate elimination of nuclear weapons are summarised. The need for including stockpiles of civil plutonium in a programme for ending production and disposing of fissile materials is emphasized, and the ultimate difficulty of disposing of the last few nuclear weapons discussed.

  19. The Nuclear Power/Nuclear Weapons Connection.

    ERIC Educational Resources Information Center

    Totten, Sam; Totten, Martha Wescoat

    1985-01-01

    Once they have nuclear power, most countries will divert nuclear materials from commercial to military programs. In excerpts from the book "Facing the Danger" (by Totten, S. and M. W., Crossing Press, 1984), five anti-nuclear activists explain how and why they have been addressing the nuclear connection. (RM)

  20. Nuclear security

    SciTech Connect

    Dingell, J.D.

    1991-02-01

    The Department of Energy's (DOE) Lawrence Livermore National Laboratory, located in Livermore, California, generates and controls large numbers of classified documents associated with the research and testing of nuclear weapons. Concern has been raised about the potential for espionage at the laboratory and the national security implications of classified documents being stolen. This paper determines the extent of missing classified documents at the laboratory and assesses the adequacy of accountability over classified documents in the laboratory's custody. Audit coverage was limited to the approximately 600,000 secret documents in the laboratory's custody. The adequacy of DOE's oversight of the laboratory's secret document control program was also assessed.

  1. NUCLEAR REACTOR

    DOEpatents

    Young, G.

    1963-01-01

    This patent covers a power-producing nuclear reactor in which fuel rods of slightly enriched U are moderated by heavy water and cooled by liquid metal. The fuel rods arranged parallel to one another in a circle are contained in a large outer closed-end conduit that extends into a tank containing the heavy water. Liquid metal is introduced into the large conduit by a small inner conduit that extends within the circle of fuel rods to a point near the lower closed end of the outer conduit. (AEC) Production Reactors

  2. Nuclear energy.

    PubMed

    Grandin, Karl; Jagers, Peter; Kullander, Sven

    2010-01-01

    Nuclear energy can play a role in carbon free production of electrical energy, thus making it interesting for tomorrow's energy mix. However, several issues have to be addressed. In fission technology, the design of so-called fourth generation reactors show great promise, in particular in addressing materials efficiency and safety issues. If successfully developed, such reactors may have an important and sustainable part in future energy production. Working fusion reactors may be even more materials efficient and environmental friendly, but also need more development and research. The roadmap for development of fourth generation fission and fusion reactors, therefore, asks for attention and research in these fields must be strengthened.

  3. Nuclear energy.

    PubMed

    Grandin, Karl; Jagers, Peter; Kullander, Sven

    2010-01-01

    Nuclear energy can play a role in carbon free production of electrical energy, thus making it interesting for tomorrow's energy mix. However, several issues have to be addressed. In fission technology, the design of so-called fourth generation reactors show great promise, in particular in addressing materials efficiency and safety issues. If successfully developed, such reactors may have an important and sustainable part in future energy production. Working fusion reactors may be even more materials efficient and environmental friendly, but also need more development and research. The roadmap for development of fourth generation fission and fusion reactors, therefore, asks for attention and research in these fields must be strengthened. PMID:20873683

  4. NUCLEAR REACTORS

    DOEpatents

    Long, E.; Ashley, J.W.

    1958-12-16

    A graphite moderator structure is described for a gas-cooled nuclear reactor having a vertical orlentation wherein the structure is physically stable with regard to dlmensional changes due to Wigner growth properties of the graphite, and leakage of coolant gas along spaces in the structure is reduced. The structure is comprised of stacks of unlform right prismatic graphite blocks positioned in layers extending in the direction of the lengths of the blocks, the adjacent end faces of the blocks being separated by pairs of tiles. The blocks and tiles have central bores which are in alignment when assembled and are provided with cooperatlng keys and keyways for physical stability.

  5. Dictionary of nuclear engineering

    SciTech Connect

    Sube, R.

    1985-01-01

    Ralf Sube, an experienced compiler of three wellknown four-language reference works has now prepared this glossary of nuclear engineering terms in English, German, French and Russian. Based on the proven lexicography of the Technik-Worterbuch series, it comprises about 30,000 terms in each language covering the following: Nuclear and Atomic Physics; Nuclear Radiation and Isotopes; Nuclear Materials; Nuclear Facilties; Nuclear Power Industry; Nuclear Weapons.

  6. NUCLEAR SUPERHEATER FOR BOILING WATER REACTOR

    DOEpatents

    Holl, R.J.; Klecker, R.W.; Graham, C.B.

    1962-05-15

    A description is given of a boiling water reactor having a superheating region integral with the core. The core consists essentially of an annular boiling region surrounding an inner superheating region. Both regions contain fuel elements and are separated by a cylindrical wall, perforations being provided in the lower portion of the cylindrical wall to permit circulation of a common water moderator between the two regions. The superheater region comprises a plurality of tubular fuel assemblies through which the steam emanating from the boiling region passes to the steam outlet. Each superheater fuel assembly has an outer double-walled cylinder, the double walls being concentrically spaced and connected together at their upper ends but open at the bottom to provide for differential thermal expansion of the inner and outer walls. Gas is entrapped in the annulus between the walls which acts as an insulating space between the fissionable material inside and the moderator outside. (AEC)

  7. Nuclear "waffles"

    NASA Astrophysics Data System (ADS)

    Schneider, A. S.; Berry, D. K.; Briggs, C. M.; Caplan, M. E.; Horowitz, C. J.

    2014-11-01

    Background: The dense neutron-rich matter found in supernovae and inside neutron stars is expected to form complex nonuniform phases, often referred to as nuclear pasta. The pasta shapes depend on density, temperature and proton fraction and determine many transport properties in supernovae and neutron star crusts. Purpose: To characterize the topology and compute two observables, the radial distribution function (RDF) g (r ) and the structure factor S (q ) , for systems with proton fractions Yp=0.10 ,0.20 ,0.30 , and 0.40 at about one-third of nuclear saturation density, n =0.050 fm-3 , and temperatures near k T =1 MeV . Methods: We use two recently developed hybrid CPU/GPU codes to perform large scale molecular dynamics (MD) simulations with 51 200 and 409 600 nucleons. From the output of the MD simulations we obtain the two desired observables. Results: We compute and discuss the differences in topology and observables for each simulation. We observe that the two lowest proton fraction systems simulated, Yp=0.10 and 0.20 , equilibrate quickly and form liquidlike structures. Meanwhile, the two higher proton fraction systems, Yp=0.30 and 0.40 , take a longer time to equilibrate and organize themselves in solidlike periodic structures. Furthermore, the Yp=0.40 system is made up of slabs, lasagna phase, interconnected by defects while the Yp=0.30 systems consist of a stack of perforated plates, the nuclear waffle phase. Conclusions: The periodic configurations observed in our MD simulations for proton fractions Yp≥0.30 have important consequences for the structure factors S (q ) of protons and neutrons, which relate to many transport properties of supernovae and neutron star crust. A detailed study of the waffle phase and how its structure depends on temperature, size of the simulation, and the screening length showed that finite-size effects appear to be under control and, also, that the plates in the waffle phase merge at temperatures slightly above 1.0 MeV and

  8. Nuclear Fusion

    NASA Astrophysics Data System (ADS)

    Veres, G.

    This chapter is devoted to the fundamental concepts of nuclear fusion. To be more precise, it is devoted to the theoretical basics of fusion reactions between light nuclei such as hydrogen, helium, boron, and lithium. The discussion is limited because our purpose is to focus on laboratory-scale fusion experiments that aim at gaining energy from the fusion process. After discussing the methods of calculating the fusion cross section, it will be shown that sustained fusion reactions with energy gain must happen in a thermal medium because, in beam-target experiments, the energy of the beam is randomized faster than the fusion rate. Following a brief introduction to the elements of plasma physics, the chapter is concluded with the introduction of the most prominent fusion reactions ongoing in the Sun.

  9. NUCLEAR REACTOR

    DOEpatents

    Grebe, J.J.

    1959-12-15

    A reactor which is particularly adapted tu serve as a heat source for a nuclear powered alrcraft or rocket is described. The core of this reactor consists of a porous refractory modera;or body which is impregnated with fissionable nuclei. The core is designed so that its surface forms tapered inlet and outlet ducts which are separated by the porous moderator body. In operation a gaseous working fluid is circulated through the inlet ducts to the surface of the moderator, enters and passes through the porous body, and is heated therein. The hot gas emerges into the outlet ducts and is available to provide thrust. The principle advantage is that tremendous quantities of gas can be quickly heated without suffering an excessive pressure drop.

  10. NUCLEAR REACTOR

    DOEpatents

    Christy, R.F.

    1958-07-15

    A nuclear reactor of the homogeneous liquid fuel type is described wherein the fissionable isotope is suspended or dissolved in a liquid moderator such as water. The reactor core is comprised essentially of a spherical vessel for containing the reactive composition surrounded by a reflector, preferably of beryllium oxide. The reactive composition may be an ordinary water solution of a soluble salt of uranium, the quantity of fissionable isotope in solution being sufficient to provide a critical mass in the vessel. The liquid fuel is stored in a tank of non-crtttcal geometry below the reactor vessel and outside of the reflector and is passed from the tank to the vessel through a pipe connecting the two by air pressure means. Neutron absorbing control and safety rods are operated within slots in the reflector adjacent to the vessel.

  11. NUCLEAR REACTOR

    DOEpatents

    Miller, H.I.; Smith, R.C.

    1958-01-21

    This patent relates to nuclear reactors of the type which use a liquid fuel, such as a solution of uranyl sulfate in ordinary water which acts as the moderator. The reactor is comprised of a spherical vessel having a diameter of about 12 inches substantially surrounded by a reflector of beryllium oxide. Conventionnl control rods and safety rods are operated in slots in the reflector outside the vessel to control the operation of the reactor. An additional means for increasing the safety factor of the reactor by raising the ratio of delayed neutrons to prompt neutrons, is provided and consists of a soluble sulfate salt of beryllium dissolved in the liquid fuel in the proper proportion to obtain the result desired.

  12. Nuclear reactor

    DOEpatents

    Wade, Elman E.

    1979-01-01

    A nuclear reactor including two rotatable plugs and a positive top core holddown structure. The top core holddown structure is divided into two parts: a small core cover, and a large core cover. The small core cover, and the upper internals associated therewith, are attached to the small rotating plug, and the large core cover, with its associated upper internals, is attached to the large rotating plug. By so splitting the core holddown structures, under-the-plug refueling is accomplished without the necessity of enlarging the reactor pressure vessel to provide a storage space for the core holddown structure during refueling. Additionally, the small and large rotating plugs, and their associated core covers, are arranged such that the separation of the two core covers to permit rotation is accomplished without the installation of complex lifting mechanisms.

  13. Nuclear exoticism

    NASA Astrophysics Data System (ADS)

    Penionzhkevich, Yu. E.

    2016-07-01

    Extreme states of nuclearmatter (such that feature high spins, large deformations, high density and temperature, or a large excess of neutrons and protons) play an important role in studying fundamental properties of nuclei and are helpful in solving the problem of constructing the equation of state for nuclear matter. The synthesis of neutron-rich nuclei near the nucleon drip lines and investigation of their properties permit drawing conclusions about the positions of these boundaries and deducing information about unusual states of such nuclei and about their decays. At the present time, experimental investigations along these lines can only be performed via the cooperation of leading research centers that possess powerful heavy-ion accelerators, such as the Large Hadron Collider (LHC) at CERN and the heavy-ion cyclotrons at the Joint Institute for Nuclear Research (JINR, Dubna), where respective experiments are being conducted by physicists from about 20 JINR member countries. The present article gives a survey of the most recent results in the realms of super neutron-rich nuclei. Implications of the change in the structure of such nuclei near the nucleon drip lines are discussed. Information about the results obtained by measuring the masses (binding energies) of exotic nuclei, the nucleon-distribution radii (neutron halo) and momentum distributions in them, and their deformations and quantum properties is presented. It is shown that the properties of nuclei lying near the stability boundaries differ strongly from the properties of other nuclei. The problem of the stability of nuclei that is associated with the magic numbers of 20 and 28 is discussed along with the effect of new magic numbers.

  14. Decommissioning of German Nuclear Research Facilities under the Governance of the Federal Ministry of Education and Research

    SciTech Connect

    Weigl, M.

    2008-07-01

    Since the announcement of the first nuclear program in 1956, nuclear R and D in Germany has been supported by the Federal Government under four nuclear programs and later on under more general energy R and D programs. The original goal was to help German industry to achieve safe, low-cost generation of energy and self-sufficiency in the various branches of nuclear technology, including the fast breeder reactor and the fuel cycle. Several national research centers were established to host or operate experimental and demonstration plants. These are mainly located at the sites of the national research centers at Juelich and Karlsruhe. In the meantime, all these facilities were shut down and most of them are now in a state of decommissioning and dismantling (D and D). Meanwhile, Germany is one of the leading countries in the world in the field of D and D. Two big demonstration plants, the Niederaichbach Nuclear Power Plant (KKN) a heavy-water cooled pressure tube reactor with carbon-dioxide cooling and the Karlstein Superheated Steam Reactor (HDR) a boiling light water reactor with a thermal power of 100 MW, are totally dismantled and 'green field' is reached. For two other projects the return to 'green field' sites will be reached by the end of this decade. These are the dismantling of the Multi-Purpose Research Reactor (MZFR) and the Compact Sodium Cooled Reactor (KNK) both located at the Forschungszentrum Karlsruhe. Within these projects a lot of new solutions und innovative techniques were tested, which were developed at German universities and in small and medium sized companies mostly funded by the Federal Ministry of Education and Research (BMBF). For example, high performance underwater cutting technologies like plasma arc cutting and contact arc metal cutting. (authors)

  15. Nuclear war: Opposing viewpoints

    SciTech Connect

    Szumski, B.

    1985-01-01

    This book presents opposing viewpoints on nuclear war. Topics discussed include: how nuclear would begin; would humanity survive; would civil defense work; will an arms agreement work; and can space weapons reduce the risk of nuclear war.

  16. Nuclear analytical chemistry

    SciTech Connect

    Brune, D.; Forkman, B.; Persson, B.

    1984-01-01

    This book covers the general theories and techniques of nuclear chemical analysis, directed at applications in analytical chemistry, nuclear medicine, radiophysics, agriculture, environmental sciences, geological exploration, industrial process control, etc. The main principles of nuclear physics and nuclear detection on which the analysis is based are briefly outlined. An attempt is made to emphasise the fundamentals of activation analysis, detection and activation methods, as well as their applications. The book provides guidance in analytical chemistry, agriculture, environmental and biomedical sciences, etc. The contents include: the nuclear periodic system; nuclear decay; nuclear reactions; nuclear radiation sources; interaction of radiation with matter; principles of radiation detectors; nuclear electronics; statistical methods and spectral analysis; methods of radiation detection; neutron activation analysis; charged particle activation analysis; photon activation analysis; sample preparation and chemical separation; nuclear chemical analysis in biological and medical research; the use of nuclear chemical analysis in the field of criminology; nuclear chemical analysis in environmental sciences, geology and mineral exploration; and radiation protection.

  17. Nuclear Quadrupole Moments and Nuclear Shell Structure

    DOE R&D Accomplishments Database

    Townes, C. H.; Foley, H. M.; Low, W.

    1950-06-23

    Describes a simple model, based on nuclear shell considerations, which leads to the proper behavior of known nuclear quadrupole moments, although predictions of the magnitudes of some quadrupole moments are seriously in error.

  18. Nuclear thermal/nuclear electric hybrids

    NASA Technical Reports Server (NTRS)

    Reid, B. D.

    1991-01-01

    A description is given of the nuclear thermal and nuclear electric hybrid. The specifications are described along with its mission performance. Next, the technical status, development requirements, and some cost estimates are provided.

  19. Nuclear Fuel Cycle & Vulnerabilities

    SciTech Connect

    Boyer, Brian D.

    2012-06-18

    The objective of safeguards is the timely detection of diversion of significant quantities of nuclear material from peaceful nuclear activities to the manufacture of nuclear weapons or of other nuclear explosive devices or for purposes unknown, and deterrence of such diversion by the risk of early detection. The safeguards system should be designed to provide credible assurances that there has been no diversion of declared nuclear material and no undeclared nuclear material and activities.

  20. Nuclear weapons modernizations

    NASA Astrophysics Data System (ADS)

    Kristensen, Hans M.

    2014-05-01

    This article reviews the nuclear weapons modernization programs underway in the world's nine nuclear weapons states. It concludes that despite significant reductions in overall weapons inventories since the end of the Cold War, the pace of reductions is slowing - four of the nuclear weapons states are even increasing their arsenals, and all the nuclear weapons states are busy modernizing their remaining arsenals in what appears to be a dynamic and counterproductive nuclear competition. The author questions whether perpetual modernization combined with no specific plan for the elimination of nuclear weapons is consistent with the nuclear Non-Proliferation Treaty and concludes that new limits on nuclear modernizations are needed.

  1. Nuclear weapons modernizations

    SciTech Connect

    Kristensen, Hans M.

    2014-05-09

    This article reviews the nuclear weapons modernization programs underway in the world's nine nuclear weapons states. It concludes that despite significant reductions in overall weapons inventories since the end of the Cold War, the pace of reductions is slowing - four of the nuclear weapons states are even increasing their arsenals, and all the nuclear weapons states are busy modernizing their remaining arsenals in what appears to be a dynamic and counterproductive nuclear competition. The author questions whether perpetual modernization combined with no specific plan for the elimination of nuclear weapons is consistent with the nuclear Non-Proliferation Treaty and concludes that new limits on nuclear modernizations are needed.

  2. Nuclear reactor

    DOEpatents

    Thomson, Wallace B.

    2004-03-16

    A nuclear reactor comprising a cylindrical pressure vessel, an elongated annular core centrally disposed within and spaced from the pressure vessel, and a plurality of ducts disposed longitudinally of the pressure vessel about the periphery thereof, said core comprising an annular active portion, an annular reflector just inside the active portion, and an annular reflector just outside the active a portion, said annular active portion comprising rectangular slab, porous fuel elements radially disposed around the inner reflector and extending the length of the active portion, wedge-shaped, porous moderator elements disposed adjacent one face of each fuel element and extending the length of the fuel element, the fuel and moderator elements being oriented so that the fuel elements face each other and the moderator elements do likewise, adjacent moderator elements being spaced to provide air inlet channels, and adjacent fuel elements being spaced to provide air outlet channels which communicate with the interior of the peripheral ducts, and means for introducing air into the air inlet channels which passes through the porous moderator elements and porous fuel elements to the outlet channel.

  3. The Arabidopsis Nuclear Pore and Nuclear Envelope

    PubMed Central

    Meier, Iris; Brkljacic, Jelena

    2010-01-01

    The nuclear envelope is a double membrane structure that separates the eukaryotic cytoplasm from the nucleoplasm. The nuclear pores embedded in the nuclear envelope are the sole gateways for macromolecular trafficking in and out of the nucleus. The nuclear pore complexes assembled at the nuclear pores are large protein conglomerates composed of multiple units of about 30 different nucleoporins. Proteins and RNAs traffic through the nuclear pore complexes, enabled by the interacting activities of nuclear transport receptors, nucleoporins, and elements of the Ran GTPase cycle. In addition to directional and possibly selective protein and RNA nuclear import and export, the nuclear pore gains increasing prominence as a spatial organizer of cellular processes, such as sumoylation and desumoylation. Individual nucleoporins and whole nuclear pore subcomplexes traffic to specific mitotic locations and have mitotic functions, for example at the kinetochores, in spindle assembly, and in conjunction with the checkpoints. Mutants of nucleoporin genes and genes of nuclear transport components lead to a wide array of defects from human diseases to compromised plant defense responses. The nuclear envelope acts as a repository of calcium, and its inner membrane is populated by functionally unique proteins connected to both chromatin and—through the nuclear envelope lumen—the cytoplasmic cytoskeleton. Plant nuclear pore and nuclear envelope research—predominantly focusing on Arabidopsis as a model—is discovering both similarities and surprisingly unique aspects compared to the more mature model systems. This chapter gives an overview of our current knowledge in the field and of exciting areas awaiting further exploration. PMID:22303264

  4. Nuclear reactor

    DOEpatents

    Pennell, William E.; Rowan, William J.

    1977-01-01

    A nuclear reactor in which the core components, including fuel-rod assemblies, control-rod assemblies, fertile rod-assemblies, and removable shielding assemblies, are supported by a plurality of separate inlet modular units. These units are referred to as inlet module units to distinguish them from the modules of the upper internals of the reactor. The modular units are supported, each removable independently of the others, in liners in the supporting structure for the lower internals of the reactor. The core assemblies are removably supported in integral receptacles or sockets of the modular units. The liners, units, sockets and assmblies have inlet openings for entry of the fluid. The modular units are each removably mounted in the liners with fluid seals interposed between the opening in the liner and inlet module into which the fluid enters and the upper and lower portion of the liner. Each assembly is similarly mounted in a corresponding receptacle with fluid seals interposed between the openings where the fluid enters and the lower portion of the receptacle or fitting closely in these regions. As fluid flows along each core assembly a pressure drop is produced along the fluid so that the fluid which emerges from each core assembly is at a lower pressure than the fluid which enters the core assembly. However because of the seals interposed in the mountings of the units and assemblies the pressures above and below the units and assemblies are balanced and the units are held in the liners and the assemblies are held in the receptacles by their weights as they have a higher specific gravity than the fluid. The low-pressure spaces between each module and its liner and between each core assembly and its module is vented to the low-pressure regions of the vessel to assure that fluid which leaks through the seals does not accumulate and destroy the hydraulic balance.

  5. Nuclear reactor

    DOEpatents

    Yant, Howard W.; Stinebiser, Karl W.; Anzur, Gregory C.

    1977-01-01

    A nuclear reactor, particularly a liquid-metal breeder reactor, whose upper internals include outlet modules for channeling the liquid-metal coolant from selected areas of the outlet of the core vertically to the outlet plenum. The modules are composed of a highly-refractory, high corrosion-resistant alloy, for example, INCONEL-718. Each module is disposed to confine and channel generally vertically the coolant emitted from a subplurality of core-component assemblies. Each module has a grid with openings, each opening disposed to receive the coolant from an assembly of the subplurality. The grid in addition serves as a holdown for the assemblies of the corresponding subplurality preventing their excessive ejection upwardly from the core. In the region directly over the core the outlet modules are of such peripheral form that they nest forming a continuum over the core-component assemblies whose outlet coolant they confine. Each subassembly includes a chimney which confines the coolant emitted by its corresponding subassemblies to generally vertical flow between the outlet of the core and the outlet plenum. Each subplurality of assemblies whose emitted coolant is confined by an outlet module includes assemblies which emit lower-temperature coolant, for example, a control-rod assembly, or fertile assemblies, and assemblies which emit coolant of substantially higher temperature, for example, fuel-rod assemblies. The coolants of different temperatures are mixed in the chimneys reducing the effect of stripping (hot-cold temperature fluctuations) on the remainder of the upper internals which are composed typically of AISI-304 or AISI-316 stainless steel.

  6. The New Nuclear Nations.

    ERIC Educational Resources Information Center

    Spector, Leonard S.

    1990-01-01

    Explores the issue of nuclear proliferation, noting that the countries with nuclear capability now include Israel, South Africa, India, and Pakistan. Describes the role and problems of the United States in halting nuclearization. Supplies charts, maps, and information concerning the state of nuclear capability in each country. (NL)

  7. Nuclear medicine annual, 1984

    SciTech Connect

    Freeman, L.M.; Weissmann, H.S.

    1984-01-01

    The following topics are reviewed in this work: nuclear physicians role in planning for and handling radiation accidents; the role of nuclear medicine in evaluating the hypertensive patient; studies of the heart with radionuclides; role of radionuclide imaging in the patient undergoing chemotherapy; hematologic nuclear medicine; the role of nuclear medicine in sports related injuries; radionuclide evaluation of hepatic function with emphasis on cholestatis.

  8. Terrorists and Nuclear Technology

    ERIC Educational Resources Information Center

    Krieger, David

    1975-01-01

    This essay explores the ways terrorist groups may gain possession of nuclear materials; the way in which they may use nuclear weapons and other nuclear technologies to their benefit; and various courses of action designed to minimize the possibilities of terrorists utilizing nuclear technology to their benefit and society's detriment. (BT)

  9. Nuclear Reaction Data Centers

    SciTech Connect

    McLane, V.; Nordborg, C.; Lemmel, H.D.; Manokhin, V.N.

    1988-01-01

    The cooperating Nuclear Reaction Data Centers are involved in the compilation and exchange of nuclear reaction data for incident neutrons, charged particles and photons. Individual centers may also have services in other areas, e.g., evaluated data, nuclear structure and decay data, reactor physics, nuclear safety; some of this information may also be exchanged between interested centers. 20 refs., 1 tab.

  10. Nuclear air cushion vehicles

    NASA Technical Reports Server (NTRS)

    Anderson, J. L.

    1973-01-01

    The state-of-the-art of the still-conceptual nuclear air cushion vehicle, particularly the nuclear powerplant is identified. Using mission studies and cost estimates, some of the advantages of nuclear power for large air cushion vehicles are described. The technology studies on mobile nuclear powerplants and conceptual ACV systems/missions studies are summarized.

  11. Frontiers of Nuclear Structure

    SciTech Connect

    Nazarewicz, Witold

    1997-12-31

    Current developments in nuclear structure at the `limits` are discussed. The studies of nuclear behavior at extreme conditions provide us with invaluable information about the nature of the nuclear interaction and nucleonic correlations at various energy-distance scales. In this talk frontiers of nuclear structure are briefly reviewed from a theoretical perspective, mainly concentrating on medium-mass and heavy nuclei.

  12. [Chilean nuclear policy].

    PubMed

    Bobadilla, E

    1996-06-01

    This official document is statement of the President of the Chilean Nuclear Energy Commission, Dr. Eduardo Bobadilla, about the nuclear policy of the Chilean State, Thanks to the international policy adopted by presidents Aylwin (1990-1994) and his successor Frei Ruiz Tagle (1994-), a nuclear development plan, protected by the Chilean entrance to the nuclear weapons non proliferation treaty and Tlatelolco Denuclearization treaty, has started. Chile will be able to develop without interference, an autonomous nuclear electrical system and other pacific uses of nuclear energy. Chile also supports a new international treaty to ban nuclear weapon tests.

  13. Intergenerational issues regarding nuclear power, nuclear waste, and nuclear weapons.

    PubMed

    Ahearne, J F

    2000-12-01

    Nuclear power, nuclear waste, and nuclear weapons raise substantial public concern in many countries. While new support for nuclear power can be found in arguments concerning greenhouse gases and global warming, the long-term existence of radioactive waste has led to requirements for 10,000-year isolation. Some of the support for such requirements is based on intergenerational equity arguments. This, however, places a very high value on lives far in the future. An alternative is to use discounting, as is applied to other resource applications. Nuclear weapons, even though being dismantled by the major nations, are growing in number due to the increase in the number of countries possessing these weapons of mass destruction. This is an unfortunate legacy for future generations. PMID:11314726

  14. Nuclear Structure Aspects in Nuclear Astrophysics

    SciTech Connect

    Smith, Michael Scott

    2006-12-01

    Nuclear Astrophysics as a broad and diverse field of study can be viewed as a magnifier of the impact of microscopic processes on the evolution of macroscopic events. One of the primary goals in Nuclear Astrophysics is the understanding of the nucleosynthesis processes that take place in the cosmos and the simulation of the correlated stellar and explosive burning scenarios. These simulations are strongly dependent on the input from Nuclear Physics which sets the time scale for all stellar dynamic processes--from giga-years of stellar evolution to milliseconds of stellar explosions--and provides the basis for most of the signatures that we have for the interpretation of these events--from stellar luminosities, elemental and isotopic abundances to neutrino flux from distant supernovae. The Nuclear Physics input comes through nuclear structure, low energy reaction rates, nuclear masses, and decay rates. There is a common perception that low energy reaction rates are the most important component of the required nuclear physics input; however, in this article we take a broader approach and present an overview of the close correlation between various nuclear structure aspects and their impact on nuclear astrophysics. We discuss the interplay between the weak and the strong forces on stellar time scales due to the limitations they provide for the evolution of slow and rapid burning processes. The effects of shell structure in nuclei on stellar burning processes as well as the impact of clustering in nuclei is outlined. Furthermore we illustrate the effects of the various nuclear structure aspects on the major nucleosynthesis processes that have been identified in the last few decades. We summarize and provide a coherent overview of the impact of all aspects of nuclear structure on nuclear astrophysics.

  15. Biogenesis of nuclear bodies.

    PubMed

    Dundr, Miroslav; Misteli, Tom

    2010-12-01

    The nucleus is unique amongst cellular organelles in that it contains a myriad of discrete suborganelles. These nuclear bodies are morphologically and molecularly distinct entities, and they host specific nuclear processes. Although the mode of biogenesis appears to differ widely between individual nuclear bodies, several common design principles are emerging, particularly, the ability of nuclear bodies to form de novo, a role of RNA as a structural element and self-organization as a mode of formation. The controlled biogenesis of nuclear bodies is essential for faithful maintenance of nuclear architecture during the cell cycle and is an important part of cellular responses to intra- and extracellular events.

  16. Nuclear Waste Disposal

    SciTech Connect

    Gee, Glendon W.; Meyer, Philip D.; Ward, Andy L.

    2005-01-12

    Nuclear wastes are by-products of nuclear weapons production and nuclear power generation, plus residuals of radioactive materials used by industry, medicine, agriculture, and academia. Their distinctive nature and potential hazard make nuclear wastes not only the most dangerous waste ever created by mankind, but also one of the most controversial and regulated with respect to disposal. Nuclear waste issues, related to uncertainties in geologic disposal and long-term protection, combined with potential misuse by terrorist groups, have created uneasiness and fear in the general public and remain stumbling blocks for further development of a nuclear industry in a world that may soon be facing a global energy crisis.

  17. Nuclear Security for Floating Nuclear Power Plants

    SciTech Connect

    Skiba, James M.; Scherer, Carolynn P.

    2015-10-13

    Recently there has been a lot of interest in small modular reactors. A specific type of these small modular reactors (SMR,) are marine based power plants called floating nuclear power plants (FNPP). These FNPPs are typically built by countries with extensive knowledge of nuclear energy, such as Russia, France, China and the US. These FNPPs are built in one country and then sent to countries in need of power and/or seawater desalination. Fifteen countries have expressed interest in acquiring such power stations. Some designs for such power stations are briefly summarized. Several different avenues for cooperation in FNPP technology are proposed, including IAEA nuclear security (i.e. safeguards), multilateral or bilateral agreements, and working with Russian design that incorporates nuclear safeguards for IAEA inspections in non-nuclear weapons states

  18. Nuclear fear revisited

    NASA Astrophysics Data System (ADS)

    Crease, Robert P.

    2010-10-01

    In 1988 the science historian Spencer Weart published a groundbreaking book called Nuclear Fear: A History of Images, which examined visions of radiation damage and nuclear disaster in newspapers, television, film, literature, advertisements and popular culture.

  19. Nuclear disarmament verification

    SciTech Connect

    DeVolpi, A.

    1993-12-31

    Arms control treaties, unilateral actions, and cooperative activities -- reflecting the defusing of East-West tensions -- are causing nuclear weapons to be disarmed and dismantled worldwide. In order to provide for future reductions and to build confidence in the permanency of this disarmament, verification procedures and technologies would play an important role. This paper outlines arms-control objectives, treaty organization, and actions that could be undertaken. For the purposes of this Workshop on Verification, nuclear disarmament has been divided into five topical subareas: Converting nuclear-weapons production complexes, Eliminating and monitoring nuclear-weapons delivery systems, Disabling and destroying nuclear warheads, Demilitarizing or non-military utilization of special nuclear materials, and Inhibiting nuclear arms in non-nuclear-weapons states. This paper concludes with an overview of potential methods for verification.

  20. Nuclear Thermal Propulsion (NTP)

    NASA Video Gallery

    NASA's history with nuclear thermal propulsion (NTP) technology goes back to the earliest days of the Agency. The Manned Lunar Rover Vehicle and the Nuclear Engine for Rocket Vehicle Applications p...

  1. Triangle Universities Nuclear Laboratory

    SciTech Connect

    Not Available

    1991-01-01

    This report contains brief papers that discusses the following topics: Fundamental Symmetries in the Nucleus; Internucleon Interactions; Dynamics of Very Light Nuclei; Facets of the Nuclear Many-Body Problem; and Nuclear Instruments and Methods.

  2. Fundamentals in Nuclear Physics

    NASA Astrophysics Data System (ADS)

    Basdevant, Jean-Louis, Rich, James, Spiro, Michael

    This course on nuclear physics leads the reader to the exploration of the field from nuclei to astrophysical issues. Much nuclear phenomenology can be understood from simple arguments such as those based on the Pauli principle and the Coulomb barrier. This book is concerned with extrapolating from such arguments and illustrating nuclear systematics with experimental data. Starting with the basic concepts in nuclear physics, nuclear models, and reactions, the book covers nuclear decays and the fundamental electro-weak interactions, radioactivity, and nuclear energy. After the discussions of fission and fusion leading into nuclear astrophysics, there is a presentation of the latest ideas about cosmology. As a primer this course will lay the foundations for more specialized subjects. This book emerged from a series of topical courses the authors delivered at the Ecole Polytechnique and will be useful for graduate students and for scientists in a variety of fields.

  3. RBC nuclear scan

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003835.htm RBC nuclear scan To use the sharing features on this page, please enable JavaScript. An RBC nuclear scan uses small amounts of radioactive material to ...

  4. Teaching "The Nuclear Predicament."

    ERIC Educational Resources Information Center

    Carman, Philip; Kneeshaw, Stephen

    1987-01-01

    Contends that courses on nuclear war must help students examine the political, social, religious, philosophical, economic, and moral assumptions which characterized the dilemma of nuclear armament/disarmament. Describes the upper level undergraduate course taught by the authors. (JDH)

  5. Nuclear radiation actuated valve

    DOEpatents

    Christiansen, David W.; Schively, Dixon P.

    1985-01-01

    A nuclear radiation actuated valve for a nuclear reactor. The valve has a valve first part (such as a valve rod with piston) and a valve second part (such as a valve tube surrounding the valve rod, with the valve tube having side slots surrounding the piston). Both valve parts have known nuclear radiation swelling characteristics. The valve's first part is positioned to receive nuclear radiation from the nuclear reactor's fuel region. The valve's second part is positioned so that its nuclear radiation induced swelling is different from that of the valve's first part. The valve's second part also is positioned so that the valve's first and second parts create a valve orifice which changes in size due to the different nuclear radiation caused swelling of the valve's first part compared to the valve's second part. The valve may be used in a nuclear reactor's core coolant system.

  6. Nuclear power browning out

    SciTech Connect

    Flavin, C.; Lenssen, N.

    1996-05-01

    When the sad history of nuclear power is written, April 26, 1986, will be recorded as the day the dream died. The explosion at the Chernobyl plant was a terrible human tragedy- and it delivered a stark verdict on the hope that nuclear power will one day replace fossil fuel-based energy systems. Nuclear advocates may soldier on, but a decade after Chernobyl it is clear that nuclear power is no longer a viable energy option for the twenty-first century.

  7. Nuclear air cushion vehicles.

    NASA Technical Reports Server (NTRS)

    Anderson, J. L.

    1973-01-01

    This paper serves several functions. It identifies the 'state-of-the-art' of the still-conceptual nuclear air cushion vehicle, particularly the nuclear powerplant. Using mission studies and cost estimates, the report describes some of the advantages of nuclear power for large air cushion vehicles. The paper also summarizes the technology studies on mobile nuclear powerplants and conceptual ACV systems/missions studies that have been performed at NASA Lewis Research Center.

  8. Nuclear fact book

    SciTech Connect

    Hill, O. F.; Platt, A. M.; Robinson, J. V.

    1983-05-01

    This reference provides significant highlights and summary facts in the following areas: general energy; nuclear energy; nuclear fuel cycle; uranium supply and enrichment; nuclear reactors; spent fuel and advanced repacking concepts; reprocessing; high-level waste; gaseous waste; transuranic waste; low-level waste; remedial action; transportation; disposal; radiation information; environment; legislation; socio-political aspects; conversion factors; and a glossary. (GHT)

  9. Nuclear energy technology

    NASA Technical Reports Server (NTRS)

    Buden, David

    1992-01-01

    An overview of space nuclear energy technologies is presented. The development and characteristics of radioisotope thermoelectric generators (RTG's) and space nuclear power reactors are discussed. In addition, the policy and issues related to public safety and the use of nuclear power sources in space are addressed.

  10. NUCLEAR REACTOR CONTROL SYSTEM

    DOEpatents

    Epler, E.P.; Hanauer, S.H.; Oakes, L.C.

    1959-11-01

    A control system is described for a nuclear reactor using enriched uranium fuel of the type of the swimming pool and other heterogeneous nuclear reactors. Circuits are included for automatically removing and inserting the control rods during the course of normal operation. Appropriate safety circuits close down the nuclear reactor in the event of emergency.

  11. Revitalizing Nuclear Safety Research.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC.

    This report covers the general issues involved in nuclear safety research and points out the areas needing detailed consideration. Topics included are: (1) "Principles of Nuclear Safety Research" (examining who should fund, who should conduct, and who should set the agenda for nuclear safety research); (2) "Elements of a Future Agenda for Nuclear…

  12. Basic Nuclear Physics.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    Basic concepts of nuclear structures, radiation, nuclear reactions, and health physics are presented in this text, prepared for naval officers. Applications to the area of nuclear power are described in connection with pressurized water reactors, experimental boiling water reactors, homogeneous reactor experiments, and experimental breeder…

  13. Effects of Nuclear Weapons.

    ERIC Educational Resources Information Center

    Sartori, Leo

    1983-01-01

    Fundamental principles governing nuclear explosions and their effects are discussed, including three components of a nuclear explosion (thermal radiation, shock wave, nuclear radiation). Describes how effects of these components depend on the weapon's yield, its height of burst, and distance of detonation point. Includes effects of three…

  14. Teaching Nuclear History.

    ERIC Educational Resources Information Center

    Holl, Jack M.; Convis, Sheila C.

    1991-01-01

    Presents results of a survey of the teaching about nuclear history at U.S. colleges and universities. Reports the existence of a well-established and extensive literature, a focus on nuclear weapons or warfare, and a concentration on nuclear citizenship, therapy, or eschatology for courses outside of history departments. Discusses individual…

  15. Commercial nuclear power 1990

    SciTech Connect

    Not Available

    1990-09-28

    This report presents the status at the end of 1989 and the outlook for commercial nuclear capacity and generation for all countries in the world with free market economies (FME). The report provides documentation of the US nuclear capacity and generation projections through 2030. The long-term projections of US nuclear capacity and generation are provided to the US Department of Energy's (DOE) Office of Civilian Radioactive Waste Management (OCRWM) for use in estimating nuclear waste fund revenues and to aid in planning the disposal of nuclear waste. These projections also support the Energy Information Administration's annual report, Domestic Uranium Mining and Milling Industry: Viability Assessment, and are provided to the Organization for Economic Cooperation and Development. The foreign nuclear capacity projections are used by the DOE uranium enrichment program in assessing potential markets for future enrichment contracts. The two major sections of this report discuss US and foreign commercial nuclear power. The US section (Chapters 2 and 3) deals with (1) the status of nuclear power as of the end of 1989; (2) projections of nuclear capacity and generation at 5-year intervals from 1990 through 2030; and (3) a discussion of institutional and technical issues that affect nuclear power. The nuclear capacity projections are discussed in terms of two projection periods: the intermediate term through 2010 and the long term through 2030. A No New Orders case is presented for each of the projection periods, as well as Lower Reference and Upper Reference cases. 5 figs., 30 tabs.

  16. History of Nuclear India

    NASA Astrophysics Data System (ADS)

    Chaturvedi, Ram

    2000-04-01

    India emerged as a free and democratic country in 1947, and entered into the nuclear age in 1948 by establishing the Atomic Energy Commission (AEC), with Homi Bhabha as the chairman. Later on the Department of Atomic Energy (DAE) was created under the Office of the Prime Minister Jawahar Lal Nehru. Initially the AEC and DAE received international cooperation, and by 1963 India had two research reactors and four nuclear power reactors. In spite of the humiliating defeat in the border war by China in 1962 and China's nuclear testing in 1964, India continued to adhere to the peaceful uses of nuclear energy. On May 18, 1974 India performed a 15 kt Peaceful Nuclear Explosion (PNE). The western powers considered it nuclear weapons proliferation and cut off all financial and technical help, even for the production of nuclear power. However, India used existing infrastructure to build nuclear power reactors and exploded both fission and fusion devices on May 11 and 13, 1998. The international community viewed the later activity as a serious road block for the Non-Proliferation Treaty and the Comprehensive Test Ban Treaty; both deemed essential to stop the spread of nuclear weapons. India considers these treaties favoring nuclear states and is prepared to sign if genuine nuclear disarmament is included as an integral part of these treaties.

  17. Thermodynamics of nuclear transport

    NASA Astrophysics Data System (ADS)

    Wang, Ching-Hao; Mehta, Pankaj; Elbaum, Michael

    Molecular transport across the nuclear envelope is important for eukaryotes for gene expression and signaling. Experimental studies have revealed that nuclear transport is inherently a nonequilibrium process and actively consumes energy. In this work we present a thermodynamics theory of nuclear transport for a major class of nuclear transporters that are mediated by the small GTPase Ran. We identify the molecular elements responsible for powering nuclear transport, which we term the ``Ran battery'' and find that the efficiency of transport, measured by the cargo nuclear localization ratio, is limited by competition between cargo molecules and RanGTP to bind transport receptors, as well as the amount of NTF2 (i.e. RanGDP carrier) available to circulate the energy flow. This picture complements our current understanding of nuclear transport by providing a comprehensive thermodynamics framework to decipher the underlying biochemical machinery. Pm and CHW were supported by a Simons Investigator in the Mathematical Modeling in Living Systems grant (to PM).

  18. Overview of nuclear data

    SciTech Connect

    Firestone, R.B.

    2003-06-30

    For many years, nuclear structure and decay data have been compiled and disseminated by an International Network of Nuclear Structure and Decay Data (NSDD) evaluators under the auspices of the International Nuclear Data Committee (INDC) of the International Atomic Energy Agency (IAEA). In this lecture I will discuss the kinds of data that are available and describe various ways to obtain this information. We will learn about some of the publications that are available and Internet sources of nuclear data. You will be introduced to Isotope Explorer software for retrieving and displaying nuclear structure and radioactive decay data. The on-line resources Table of Radioactive Isotopes, PGAA Database Viewer, Nuclear Science Reference Search, Table of Isotopes Educational Website, and other information sources will be discussed. Exercises will be provided to increase your ability to understand, access, and use nuclear data.

  19. Environmental consequences of nuclear war

    SciTech Connect

    Harwell, M.A.; Hutchinson, T.C.; Cropper, W.P. Jr.; Harwell, C.C.; Grover, H.D.

    1989-01-01

    This book addresses the ecological, agricultural, and human effects of nuclear war. The topics covered include: Ecological principles relevant to nuclear war; Vulnerability of ecological systems to climatic effects on nuclear war; Additional potential effects of nuclear war on ecological systems; Potential effects of nuclear war on agricultural productivity; Food availability after nuclear war; and Experiences and extrapolations from Hiroshima and Nagasaki.

  20. Nuclear Reactor Physics

    NASA Astrophysics Data System (ADS)

    Stacey, Weston M.

    2001-02-01

    An authoritative textbook and up-to-date professional's guide to basic and advanced principles and practices Nuclear reactors now account for a significant portion of the electrical power generated worldwide. At the same time, the past few decades have seen an ever-increasing number of industrial, medical, military, and research applications for nuclear reactors. Nuclear reactor physics is the core discipline of nuclear engineering, and as the first comprehensive textbook and reference on basic and advanced nuclear reactor physics to appear in a quarter century, this book fills a large gap in the professional literature. Nuclear Reactor Physics is a textbook for students new to the subject, for others who need a basic understanding of how nuclear reactors work, as well as for those who are, or wish to become, specialists in nuclear reactor physics and reactor physics computations. It is also a valuable resource for engineers responsible for the operation of nuclear reactors. Dr. Weston Stacey begins with clear presentations of the basic physical principles, nuclear data, and computational methodology needed to understand both the static and dynamic behaviors of nuclear reactors. This is followed by in-depth discussions of advanced concepts, including extensive treatment of neutron transport computational methods. As an aid to comprehension and quick mastery of computational skills, he provides numerous examples illustrating step-by-step procedures for performing the calculations described and chapter-end problems. Nuclear Reactor Physics is a useful textbook and working reference. It is an excellent self-teaching guide for research scientists, engineers, and technicians involved in industrial, research, and military applications of nuclear reactors, as well as government regulators who wish to increase their understanding of nuclear reactors.

  1. British nuclear policymaking

    SciTech Connect

    Bowie, C.J.; Platt, A.

    1984-01-01

    This study analyzes the domestic political, economic, and bureaucratic factors that affect the nuclear policymaking process in Great Britain. Its major conclusion is that, although there have been changes in that process in recent years (notably the current involvement of a segment of the British public in the debate about the deployment of intermediate-range nuclear forces), future British nuclear policymaking will remain much what it has been in the past. Three ideas are central to understanding British thinking on the subject: (1) Britain's long-standing resolve to have her own national nuclear force is largely traceable to her desire to maintain first-rank standing among the nations of the world in spite of loss of empire. (2) Financial considerations have always been important--so much so that they have usually dominated issues of nuclear policy. (3) The executive branch of government dominates the nuclear policymaking process but does not always present a united front. The United States heavily influences British nuclear policy through having supplied Britain since the late 1950s with nuclear data and components of nuclear weapon systems such as Polaris and Trident. The relationship works both ways since the U.S. depends on Britain as a base for deployment of both conventional and nuclear systems.

  2. NUCLEAR DATABASES FOR REACTOR APPLICATIONS.

    SciTech Connect

    PRITYCHENKO, B.; ARCILLA, R.; BURROWS, T.; HERMAN, M.W.; MUGHABGHAB, S.; OBLOZINSKY, P.; ROCHMAN, D.; SONZOGNI, A.A.; TULI, J.; WINCHELL, D.F.

    2006-06-05

    The National Nuclear Data Center (NNDC): An overview of nuclear databases, related products, nuclear data Web services and publications. The NNDC collects, evaluates, and disseminates nuclear physics data for basic research and applied nuclear technologies. The NNDC maintains and contributes to the nuclear reaction (ENDF, CSISRS) and nuclear structure databases along with several others databases (CapGam, MIRD, IRDF-2002) and provides coordination for the Cross Section Evaluation Working Group (CSEWG) and the US Nuclear Data Program (USNDP). The Center produces several publications and codes such as Atlas of Neutron Resonances, Nuclear Wallet Cards booklets and develops codes, such as nuclear reaction model code Empire.

  3. Nuclear Science References Database

    SciTech Connect

    Pritychenko, B.; Běták, E.; Singh, B.; Totans, J.

    2014-06-15

    The Nuclear Science References (NSR) database together with its associated Web interface, is the world's only comprehensive source of easily accessible low- and intermediate-energy nuclear physics bibliographic information for more than 210,000 articles since the beginning of nuclear science. The weekly-updated NSR database provides essential support for nuclear data evaluation, compilation and research activities. The principles of the database and Web application development and maintenance are described. Examples of nuclear structure, reaction and decay applications are specifically included. The complete NSR database is freely available at the websites of the National Nuclear Data Center (http://www.nndc.bnl.gov/nsr) and the International Atomic Energy Agency (http://www-nds.iaea.org/nsr)

  4. Ongoing Space Nuclear Activities

    NASA Technical Reports Server (NTRS)

    Houts, Michael G.

    2007-01-01

    Most ongoing US activities related to space nuclear power and propulsion are sponsored by NASA. NASA-spons0red space nuclear work is currently focused on evaluating potential fission surface power (FSP) systems and on radioisotope power systems (RPS). In addition, significant efforts related to nuclear thermal propulsion (NTP) systems have been completed and will provide a starting point for potential future NTP work.

  5. Assessing the nuclear age

    SciTech Connect

    Ackland, L.; McGuire, S.

    1986-01-01

    This book presents papers on nuclear weapons and arms control. Topics considered include historical aspects, the arms race, nuclear power, flaws in the non-proliferation treaty, North-South issues, East-West confrontation, Soviet decision making with regard to national defense, US and Soviet perspectives on national security, ballistic missile defense (''Star Wars''), political aspects, nuclear winter, stockpiles, US foreign policy, and military strategy.

  6. Nuclear power in space

    SciTech Connect

    Aftergood, S. ); Hafemeister, D.W. ); Prilutsky, O.F.; Rodionov, S.N. ); Primack, J.R. )

    1991-06-01

    Nuclear reactors have provided energy for satellites-with nearly disastrous results. Now the US government is proposing to build nuclear-powered boosters to launch Star Wars defenses. These authors represent scientific groups that are opposed to the use of nuclear power in near space. The authors feel that the best course for space-borne reactors is to ban them from Earth orbit and use them in deep space.

  7. Nuclear power in space

    NASA Astrophysics Data System (ADS)

    Written and verbal testimony presented before the House Subcommittee on Energy Research and Development is documented. Current research efforts related to space nuclear power are discussed including the SP-100 Space Reactor Program, development of radioisotope thermoelectric generators, and the Advanced Nuclear Systems Program. Funding, research and test facilities, specific space mission requirements, and the comparison of solar and nuclear power systems are addressed. Witnesses included representatives from DOD, NASA, DOE, universities, and private industry.

  8. Nuclear Proliferation Challenges

    SciTech Connect

    Professor William Potter

    2005-11-28

    William C. Potter, Director of the Center for Non Proliferation Studies and the Center for Russian and Eurasian Studies at the Monterey Institute of International Studies, will present nuclear proliferation challenges following the 2005 Nuclear Non-Proliferation Treaty (NPT) Review Conference. In addition to elucidating reasons for, and implications of, the conference’s failure, Dr. Potter will discuss common ground between nuclear proliferation and terrorism issues and whether corrective action can be taken.

  9. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.

    2012-05-15

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  10. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.

    2010-07-13

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  11. Nuclear Fabrication Consortium

    SciTech Connect

    Levesque, Stephen

    2013-04-05

    This report summarizes the activities undertaken by EWI while under contract from the Department of Energy (DOE) Office of Nuclear Energy (NE) for the management and operation of the Nuclear Fabrication Consortium (NFC). The NFC was established by EWI to independently develop, evaluate, and deploy fabrication approaches and data that support the re-establishment of the U.S. nuclear industry: ensuring that the supply chain will be competitive on a global stage, enabling more cost-effective and reliable nuclear power in a carbon constrained environment. The NFC provided a forum for member original equipment manufactures (OEM), fabricators, manufacturers, and materials suppliers to effectively engage with each other and rebuild the capacity of this supply chain by : Identifying and removing impediments to the implementation of new construction and fabrication techniques and approaches for nuclear equipment, including system components and nuclear plants. Providing and facilitating detailed scientific-based studies on new approaches and technologies that will have positive impacts on the cost of building of nuclear plants. Analyzing and disseminating information about future nuclear fabrication technologies and how they could impact the North American and the International Nuclear Marketplace. Facilitating dialog and initiate alignment among fabricators, owners, trade associations, and government agencies. Supporting industry in helping to create a larger qualified nuclear supplier network. Acting as an unbiased technology resource to evaluate, develop, and demonstrate new manufacturing technologies. Creating welder and inspector training programs to help enable the necessary workforce for the upcoming construction work. Serving as a focal point for technology, policy, and politically interested parties to share ideas and concepts associated with fabrication across the nuclear industry. The report the objectives and summaries of the Nuclear Fabrication Consortium

  12. Nuclear free zone

    SciTech Connect

    Christoffel, T.

    1987-07-01

    Health professionals have played a leading role in alerting and educating the public regarding the danger of nuclear war which has been described as the last epidemic our civilization will know. Having convinced most people that the use of nuclear weapons would mean intolerable consequences, groups such as Physicians for Social Responsibility have focused on the second critical question how likely is it that these weapons will be used. The oultlook is grim. This article describes the nuclear free zone movement, explores relevant legal questions, and shows how the political potential of nuclear free zones threatens to open a deep rift in the American constitutional system.

  13. Nuclear reactor apparatus

    DOEpatents

    Wade, Elman E.

    1978-01-01

    A lifting, rotating and sealing apparatus for nuclear reactors utilizing rotating plugs above the nuclear reactor core. This apparatus permits rotation of the plugs to provide under the plug refueling of a nuclear core. It also provides a means by which positive top core holddown can be utilized. Both of these operations are accomplished by means of the apparatus lifting the top core holddown structure off the nuclear core while stationary, and maintaining this structure in its elevated position during plug rotation. During both of these operations, the interface between the rotating member and its supporting member is sealingly maintained.

  14. Technologists for Nuclear Medicine

    ERIC Educational Resources Information Center

    Barnett, Huey D.

    1974-01-01

    Physicians need support personnel for work with radioisotopes in diagnosing dangerous diseases. The Nuclear Medicine Technology (NMT) Program at Hillsborough Community College in Tampa, Florida, is described. (MW)

  15. Nuclear Energy and the Environment.

    ERIC Educational Resources Information Center

    International Atomic Energy Agency, Vienna (Austria).

    "Nuclear Energy and the Environment" is a pocket folder of removable leaflets concerned with two major topics: Nuclear energy and Nuclear Techniques. Under Nuclear Energy, leaflets concerning the topics of "Radiation--A Fact of Life,""The Impact of a Fact: 1963 Test Ban Treaty,""Energy Needs and Nuclear Power,""Power Reactor Safety,""Transport,"…

  16. Gordon Conference on Nuclear Research

    SciTech Connect

    Austin, S.M.

    1983-09-01

    Session topics were: quarks and nuclear physics; anomalons and anti-protons; the independent particle structure of nuclei; relativistic descriptions of nuclear structure and scattering; nuclear structure at high excitation; advances in nuclear astrophysics; properties of nuclear material; the earliest moments of the universe; and pions and spin excitations in nuclei.

  17. Nuclear-Powered Debate.

    ERIC Educational Resources Information Center

    Arce, Gary

    1992-01-01

    Describes an exercise to develop interest and understanding about nuclear energy in which students make presentations regarding a proposal to build a hypothetical nuclear power plant. Students spend two weeks researching the topic; give testimony before a "Senate Energy Committee"; and vote on the proposal. Background information is provided. (MDH)

  18. Exotic nuclear matter

    NASA Astrophysics Data System (ADS)

    Lenske, H.; Dhar, M.; Tsoneva, N.; Wilhelm, J.

    2016-01-01

    Recent developments of nuclear structure theory for exotic nuclei are addressed. The inclusion of hyperons and nucleon resonances is discussed. Nuclear multipole response functions, hyperon interactions in infinite matter and in neutron stars and theoretical aspects of excitations of nucleon resonances in nuclei are discussed.

  19. Nuclear Taskforce Summation.

    ERIC Educational Resources Information Center

    1979

    At the end of 1978, there were approximately 230 nuclear-fueled electric generating plants around the world; 72 of these were in the United States. Each plant requires an operations-and-maintenance workforce of 92 people, and attrition occurs at a rate of 8% per year. Requirements for a nuclear taskforce and job training, in view of current…

  20. High energy nuclear structures

    SciTech Connect

    Boguta, J.; Kunz, J.

    1984-03-09

    In conventional nuclear physics the nucleus is described as a non-relativistic many-body system, which is governed by the Schroedinger equation. Nucleons interact in this framework via static two-body potentials, mesonic degrees of freedom are neglected. An alternative description of nuclear physics in terms of a relativistic field theory has been developed by Walecka. The model Lagrangian containing baryons, sigma-mesons and ..omega..-mesons was subsequently extended to include also ..pi..-mesons and rho-mesons. An essential feature of such a nuclear Lagrangian is its renormalizability. In addition to the description of known nuclear structure the field theoretical approach may reveal entirely new nuclear phenomena, based on the explicit treatment of mesonic degrees of freedom. The existence of such abnormal nuclear states was proposed by Lee and Wick employing the sigma-model Lagrangian. There the non-linearity of the meson field equations allows for soliton solutions in the presence of nucleons, in particular the sigma-field may exhibit a kink. Different types of soliton solutions occur in gauge theories with hidden symmetries. In the phenomenological Lagrangian the rho-meson is described by a non-abelian gauge field, that acquires its mass spontaneously due to the non-vanishing vacuum expectation value of a Higgs field. A general ansatz for soliton solutions of such a gauge theory was given by Dashen et al. A specific solution and its possible implications for nuclear physics like anomalous nuclear states were discussed by Boguta.

  1. Nuclear Charge Radii Systematics

    SciTech Connect

    Marinova, Krassimira

    2015-09-15

    This paper is a brief overview of the existing systematics on nuclear mean square charge radii, obtained by a combined analysis of data from different types of experiment. The various techniques yielding data on nuclear charge radii are summarized. Their specific feature complexities and the accuracy and precision of the obtained information are also discussed.

  2. Talk About Nuclear Power

    ERIC Educational Resources Information Center

    Tremlett, Lewis

    1976-01-01

    Presents an overview of the relation of nuclear power to human health and the environment, and discusses the advantages and disadvantages of nuclear power as an energy source urging technical educators to inculcate an awareness of the problems associated with the production of energy. Describes the fission reaction process, the hazards of…

  3. Nuclear physics and cosmology

    SciTech Connect

    Coc, Alain

    2014-05-09

    There are important aspects of Cosmology, the scientific study of the large scale properties of the universe as a whole, for which nuclear physics can provide insights. Here, we will focus on Standard Big-Bang Nucleosynthesis and we refer to the previous edition of the School [1] for the aspects concerning the variations of constants in nuclear cosmo-physics.

  4. Nuclear effects at HERA

    SciTech Connect

    Brodsky, S.J.

    1996-07-01

    The development of a nuclear beam facility at HERA would allow the study of fundamental features of quark and gluon interactions in QCD. I briefly review the physics underlying nuclear shadowing and anti-shadowing as well as other diffractive and jet fragmentation processes that can be studies in high energy electron-nucleus collisions.

  5. Nuclear Shuttle in Flight

    NASA Technical Reports Server (NTRS)

    1970-01-01

    This 1970 artist's concept shows a Nuclear Shuttle in flight. As envisioned by Marshall Space Flight Center Program Development engineers, the Nuclear Shuttle would deliver payloads to lunar orbit or other destinations then return to Earth orbit for refueling and additional missions.

  6. Nucleation of nuclear bodies.

    PubMed

    Dundr, Miroslav

    2013-01-01

    The nucleus is a complex organelle containing numerous highly dynamic, structurally stable domains and bodies, harboring functions that have only begun to be defined. However, the molecular mechanisms for their formation are still poorly understood. Recently it has been shown that a nuclear body can form de novo by self-organization. But little is known regarding what triggers the formation of a nuclear body and how subsequent assembly steps are orchestrated. Nuclear bodies are frequently associated with specific active gene loci that directly contribute to their formation. Both coding and noncoding RNAs can initiate the assembly of nuclear bodies with which they are physiologically associated. Thus, the formation of nuclear bodies occurs via recruitment and consequent accumulation of resident proteins in the nuclear bodies by nucleating RNA acting as a seeder. In this chapter I describe how to set up an experimental cell system to probe de novo biogenesis of a nuclear body by nucleating RNA and nuclear body components tethered on chromatin. PMID:23980018

  7. Nuclear Power Plants. Revised.

    ERIC Educational Resources Information Center

    Lyerly, Ray L.; Mitchell, Walter, III

    This publication is one of a series of information booklets for the general public published by the United States Atomic Energy Commission. Among the topics discussed are: Why Use Nuclear Power?; From Atoms to Electricity; Reactor Types; Typical Plant Design Features; The Cost of Nuclear Power; Plants in the United States; Developments in Foreign…

  8. Nuclear Weapons and Schools.

    ERIC Educational Resources Information Center

    Howie, David I.

    1984-01-01

    The growing debate on nuclear weapons in recent years has begun to make inroads into school curricula. Elementary and secondary school teachers now face the important task of educating their students on issues relating to nuclear war without indoctrinating them to a particular point of view. (JBM)

  9. Vertical nuclear proliferation.

    PubMed

    Sidel, Victor W

    2007-01-01

    All the nuclear-weapon states are working to develop new nuclear-weapon systems and upgrade their existing ones. Although the US Congress has recently blocked further development of small nuclear weapons and earth-penetrating nuclear weapons, the United States is planning a range of new warheads under the Reliable Replacement Warhead programme, and renewing its nuclear weapons infrastructure. The United Kingdom is spending 1 billion pounds sterling on updating the Atomic Weapons Establishment at Aldermaston, and about 20 billion pounds sterling on replacing its Vanguard submarines and maintaining its Trident warhead stockpile. The US has withdrawn from the Anti-Ballistic Missile Treaty and plans to install missile defence systems in Poland and the Czech Republic; Russia threatens to upgrade its nuclear countermeasures. The nuclear-weapon states should comply with their obligations under Article VI of the Non-Proliferation Treaty, as summarised in the 13-point plan agreed at the 2000 NPT Review Conference, and they should negotiate a Nuclear Weapons Convention.

  10. Nuclear Power Plant Technician

    ERIC Educational Resources Information Center

    Randall, George A.

    1975-01-01

    The author recognizes a body of basic knowledge in nuclear power plant technoogy that can be taught in school programs, and lists the various courses, aiming to fill the anticipated need for nuclear-trained manpower--persons holding an associate degree in engineering technology. (Author/BP)

  11. Vented nuclear fuel element

    DOEpatents

    Grossman, Leonard N.; Kaznoff, Alexis I.

    1979-01-01

    A nuclear fuel cell for use in a thermionic nuclear reactor in which a small conduit extends from the outside surface of the emitter to the center of the fuel mass of the emitter body to permit escape of volatile and gaseous fission products collected in the center thereof by virtue of molecular migration of the gases to the hotter region of the fuel.

  12. Under the Nuclear Umbrella.

    ERIC Educational Resources Information Center

    Williams, Leon F.

    1987-01-01

    Entertains the thesis that social work has a stake in the technological-humanistic debate and should greet the recent and spectacular technological failures with protest and alarm. Discusses relationship of nuclear issue and social work, effects of nuclear issue on children, and Chernobyl. Advocates pacifism, activism, and a coherent conception of…

  13. TRAINING NUCLEAR TECHNICIANS.

    ERIC Educational Resources Information Center

    KOVNER, EDGAR A.

    PROBLEMS CONFRONTED BY PLANNERS OF NUCLEAR PROGRAMS AT THE TECHNICIAN LEVEL INCLUDE (1) LACK OF PRECEDENT IN CURRICULUM, COURSE OUTLINES, AND GRADUATE PLACEMENT, (2) DIFFICULTY IN DETERMINING COSTS OF LABORATORY CONSTRUCTION, EQUIPMENT, AND OPERATION, AND (3) REQUIREMENT OF ATOMIC ENERGY COMMISSION LICENSES IN NUCLEAR OCCUPATIONS. A 92-SEMESTER…

  14. Lipid droplets go nuclear.

    PubMed

    Farese, Robert V; Walther, Tobias C

    2016-01-01

    Lipid droplets (LDs) are sometimes found in the nucleus of some cells. In this issue, Ohsaki et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201507122) show that the nuclear membrane, promyelocytic leukemia bodies, and the protein PML-II play a role in nuclear LD formation, suggesting functional relationships between these structures. PMID:26728852

  15. Nuclear physics: Macroscopic aspects

    SciTech Connect

    Swiatecki, W.J.

    1993-12-01

    A systematic macroscopic, leptodermous approach to nuclear statics and dynamics is described, based formally on the assumptions {h_bar} {yields} 0 and b/R << 1, where b is the surface diffuseness and R the nuclear radius. The resulting static model of shell-corrected nuclear binding energies and deformabilities is accurate to better than 1 part in a thousand and yields a firm determination of the principal properties of the nuclear fluid. As regards dynamics, the above approach suggests that nuclear shape evolutions will often be dominated by dissipation, but quantitative comparisons with experimental data are more difficult than in the case of statics. In its simplest liquid drop version the model exhibits interesting formal connections to the classic astronomical problem of rotating gravitating masses.

  16. World nuclear outlook 1994

    SciTech Connect

    1994-12-01

    As part of the EIA program to provide energy information, this analysis report presents the current status and projections through 2010 of nuclear capacity, generation, and fuel cycle requirements for all countries in the world using nuclear power to generate electricity for commercial use. It also contains information and forecasts of developments in the uranium market. Long-term projections of US nuclear capacity, generation, and spent fuel discharges for three different scenarios through 2040 are developed for the Department of Energy`s Office of Civilian Radioactive Waste Management (OCRWM). In turn, the OCRWM provides partial funding for preparation of this report. The projections of uranium requirements are provided to the Organization for Economic Cooperation and Development (OECD) for preparation of the Nuclear Energy Agency/OECD report, Summary of Nuclear Power and Fuel Cycle Data in OECD Member Countries.

  17. World nuclear outlook 1995

    SciTech Connect

    1995-09-29

    As part of the EIA program to provide energy information, this analysis report presents the current status and projections through 2015 of nuclear capacity, generation, and fuel cycle requirements for all countries in the world using nuclear power to generate electricity for commercial use. It also contains information and forecasts of developments in the uranium market. Long-term projections of US nuclear capacity, generation, and spent fuel discharges for two different scenarios through 2040 are developed for the Department of Energy`s Office of Civilian Radioactive Waste Management (OCRWM). In turn, the OCRWM provides partial funding for preparation of this report. The projections of uranium requirements are provided to the Organization for Economic Cooperation and Development (OECD) for preparation of the Nuclear Energy Agency/OECD report, Summary of Nuclear Power and Fuel Cycle Data in OECD Member Countries.

  18. Nuclear war, nuclear proliferation, and their consequences

    SciTech Connect

    Sanruddin, A.K.

    1986-01-01

    The proceedings of a colloquium convened by the Groupe de Bellerive offers the contributions of Carl Sagan, Gabriel Garcia Marquez, Kenneth Galbraith, Pierre Trudeau, Edward Kennedy, and other eminent scientists, politicians, and strategists on the subject of the proliferation of nuclear weaponry and its potential ramifications.

  19. Nuclear excitation and precompound nuclear reactions

    SciTech Connect

    De, A.; Ray, S.; Ghosh, S.K.

    1988-06-01

    The angular distribution of nucleons emitted in nucleon-induced precompound nuclear reactions are calculated taking into account the effect of excitation on the kinematics of nucleon-nucleon scattering inside the target-plus-projectile system. The results are compared with quantum mechanical calculations and those of reaction models based on a pure nucleon-nucleon collision picture.

  20. Nuclear Powerplant Safety: Source Terms. Nuclear Energy.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC. Nuclear Energy Office.

    There has been increased public interest in the potential effects of nuclear powerplant accidents since the Soviet reactor accident at Chernobyl. People have begun to look for more information about the amount of radioactivity that might be released into the environment as a result of such an accident. When this issue is discussed by people…

  1. The nuclear pore complex and nuclear transport.

    PubMed

    Wente, Susan R; Rout, Michael P

    2010-10-01

    Internal membrane bound structures sequester all genetic material in eukaryotic cells. The most prominent of these structures is the nucleus, which is bounded by a double membrane termed the nuclear envelope (NE). Though this NE separates the nucleoplasm and genetic material within the nucleus from the surrounding cytoplasm, it is studded throughout with portals called nuclear pore complexes (NPCs). The NPC is a highly selective, bidirectional transporter for a tremendous range of protein and ribonucleoprotein cargoes. All the while the NPC must prevent the passage of nonspecific macromolecules, yet allow the free diffusion of water, sugars, and ions. These many types of nuclear transport are regulated at multiple stages, and the NPC carries binding sites for many of the proteins that modulate and modify the cargoes as they pass across the NE. Assembly, maintenance, and repair of the NPC must somehow occur while maintaining the integrity of the NE. Finally, the NPC appears to be an anchor for localization of many nuclear processes, including gene activation and cell cycle regulation. All these requirements demonstrate the complex design of the NPC and the integral role it plays in key cellular processes. PMID:20630994

  2. Nuclear Thermal Propulsion (NTP): A Proven Growth Technology for Human NEO/Mars Exploration Missions

    NASA Technical Reports Server (NTRS)

    Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.

    2012-01-01

    The nuclear thermal rocket (NTR) represents the next "evolutionary step" in high performance rocket propulsion. Unlike conventional chemical rockets that produce their energy through combustion, the NTR derives its energy from fission of Uranium-235 atoms contained within fuel elements that comprise the engine s reactor core. Using an "expander" cycle for turbopump drive power, hydrogen propellant is raised to a high pressure and pumped through coolant channels in the fuel elements where it is superheated then expanded out a supersonic nozzle to generate high thrust. By using hydrogen for both the reactor coolant and propellant, the NTR can achieve specific impulse (Isp) values of 900 seconds (s) or more - twice that of today s best chemical rockets. From 1955 - 1972, twenty rocket reactors were designed, built and ground tested in the Rover and NERVA (Nuclear Engine for Rocket Vehicle Applications) programs. These programs demonstrated: (1) high temperature carbide-based nuclear fuels; (2) a wide range of thrust levels; (3) sustained engine operation; (4) accumulated lifetime at full power; and (5) restart capability - all the requirements needed for a human Mars mission. Ceramic metal "cermet" fuel was pursued as well, as a backup option. The NTR also has significant "evolution and growth" capability. Configured as a "bimodal" system, it can generate its own electrical power to support spacecraft operational needs. Adding an oxygen "afterburner" nozzle introduces a variable thrust and Isp capability and allows bipropellant operation. In NASA s recent Mars Design Reference Architecture (DRA) 5.0 study, the NTR was selected as the preferred propulsion option because of its proven technology, higher performance, lower launch mass, versatile vehicle design, simple assembly, and growth potential. In contrast to other advanced propulsion options, no large technology scale-ups are required for NTP either. In fact, the smallest engine tested during the Rover program

  3. Intramolecular Nuclear Flux Densities

    NASA Astrophysics Data System (ADS)

    Barth, I.; Daniel, C.; Gindensperger, E.; Manz, J.; PéRez-Torres, J. F.; Schild, A.; Stemmle, C.; Sulzer, D.; Yang, Y.

    The topic of this survey article has seen a renaissance during the past couple of years. Here we present and extend the results for various phenomena which we have published from 2012-2014, with gratitude to our coauthors. The new phenomena include (a) the first reduced nuclear flux densities in vibrating diatomic molecules or ions which have been deduced from experimental pump-probe spectra; these "experimental" nuclear flux densities reveal several quantum effects including (b) the "quantum accordion", i.e., during the turn from bond stretch to bond compression, the diatomic system never stands still — instead, various parts of it with different bond lengths flow into opposite directions. (c) Wavepacket interferometry has been extended from nuclear densities to flux densities, again revealing new phenomena: For example, (d) a vibrating nuclear wave function with compact initial shape may split into two partial waves which run into opposite directions, thus causing interfering flux densities. (e) Tunneling in symmetric 1-dimensional double-well systems yields maximum values of the associated nuclear flux density just below the potential barrier; this is in marked contrast with negligible values of the nuclear density just below the barrier. (f) Nuclear flux densities of pseudorotating nuclei may induce huge magnetic fields. A common methodologic theme of all topics is the continuity equation which connects the time derivative of the nuclear density to the divergence of the flux density, subject to the proper boundary conditions. (g) Nearly identical nuclear densities with different boundary conditions may be related to entirely different flux densities, e.g., during tunneling in cyclic versus non-cyclic systems. The original continuity equation, density and flux density of all nuclei, or of all nuclear degrees of freedom, may be reduced to the corresponding quantities for just a single nucleus, or just a single degree of freedom.

  4. US nuclear weapons policy

    SciTech Connect

    May, M.

    1990-12-05

    We are closing chapter one'' of the nuclear age. Whatever happens to the Soviet Union and to Europe, some of the major determinants of nuclear policy will not be what they have been for the last forty-five years. Part of the task for US nuclear weapons policy is to adapt its nuclear forces and the oganizations managing them to the present, highly uncertain, but not urgently competitive situation between the US and the Soviet Union. Containment is no longer the appropriate watchword. Stabilization in the face of uncertainty, a more complicated and politically less readily communicable goal, may come closer. A second and more difficult part of the task is to deal with what may be the greatest potential source of danger to come out of the end of the cold war: the breakup of some of the cooperative institutions that managed the nuclear threat and were created by the cold war. These cooperative institutions, principally the North Atlantic Treaty Organization (NATO), the Warsaw Pact, the US-Japan alliance, were not created specifically to manage the nuclear threat, but manage it they did. A third task for nuclear weapons policy is that of dealing with nuclear proliferation under modern conditions when the technologies needed to field effective nuclear weapons systems and their command and control apparatus are ever more widely available, and the leverage over some potential proliferators, which stemmed from superpower military support, is likely to be on the wane. This paper will make some suggestions regarding these tasks, bearing in mind that the unsettled nature of that part of the world most likely to become involved in nuclear weapons decisions today must make any suggestions tentative and the allowance for surprise more than usually important.

  5. 76 FR 19148 - Entergy Nuclear Operations, Inc., Entergy Nuclear Vermont Yankee, LLC, Vermont Yankee Nuclear...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-06

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Entergy Nuclear Operations, Inc., Entergy Nuclear Vermont Yankee, LLC, Vermont Yankee Nuclear... (10 CFR), Section 2.206, ``Requests for Action under this Subpart,'' the U.S. Nuclear...

  6. 75 FR 39057 - Entergy Nuclear Operations, Inc.; Entergy Nuclear Vermont Yankee, LLC; Vermont Yankee Nuclear...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Entergy Nuclear Operations, Inc.; Entergy Nuclear Vermont Yankee, LLC; Vermont Yankee Nuclear... CFR), Section 2.206, ``Requests for Action under this Subpart,'' the U.S. Nuclear...

  7. The nuclear dynamo; Can a nuclear tornado annihilate nations

    SciTech Connect

    McNally, J.R. Jr.

    1991-01-01

    This paper reports on the development of the hypothesis of a nuclear dynamo for a controlled nuclear fusion reactor. This dynamo hypothesis suggests properties for a nuclear tornado that could annihilate nations if accidentally triggered by a single high yield to weight nuclear weapon detonation. The formerly classified reports on ignition of the atmosphere, the properties of a nuclear dynamo, methods to achieve a nuclear dynamo in the laboratory, and the analogy of a nuclear dynamo to a nuclear tornado are discussed. An unclassified international study of this question is urged.

  8. Supporting Our Nation's Nuclear Industry

    SciTech Connect

    Lyons, Peter

    2011-01-01

    On the 60th anniversary of the world's first nuclear power plant to produce electricity, Assistant Secretary for Nuclear Energy Peter Lyons discusses the Energy Department's and the Administration's commitment to promoting a nuclear renaissance in the United States.

  9. Radiological Effects of Nuclear War.

    ERIC Educational Resources Information Center

    Shapiro, Charles S.

    1988-01-01

    Described are the global effects of nuclear war. Discussed are radiation dosages, limited nuclear attacks, strategic arms reductions, and other results reported at the workshop on nuclear war issues in Moscow in March 1988. (CW)

  10. Supporting Our Nation's Nuclear Industry

    ScienceCinema

    Lyons, Peter

    2016-07-12

    On the 60th anniversary of the world's first nuclear power plant to produce electricity, Assistant Secretary for Nuclear Energy Peter Lyons discusses the Energy Department's and the Administration's commitment to promoting a nuclear renaissance in the United States.

  11. Your Radiologist Explains Nuclear Medicine

    MedlinePlus

    ... produced by: Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org ... I’d like to talk to you about nuclear medicine. Nuclear medicine offers the potential to identify ...

  12. Nuclear forensics: Soil content

    SciTech Connect

    Beebe, Merilyn Amy

    2015-08-31

    Nuclear Forensics is a growing field that is concerned with all stages of the process of creating and detonating a nuclear weapon. The main goal is to prevent nuclear attack by locating and securing nuclear material before it can be used in an aggressive manner. This stage of the process is mostly paperwork; laws, regulations, treaties, and declarations made by individual countries or by the UN Security Council. There is some preliminary leg work done in the form of field testing detection equipment and tracking down orphan materials; however, none of these have yielded any spectacular or useful results. In the event of a nuclear attack, the first step is to analyze the post detonation debris to aid in the identification of the responsible party. This aspect of the nuclear forensics process, while reactive in nature, is more scientific. A rock sample taken from the detonation site can be dissolved into liquid form and analyzed to determine its chemical composition. The chemical analysis of spent nuclear material can provide valuable information if properly processed and analyzed. In order to accurately evaluate the results, scientists require information on the natural occurring elements in the detonation zone. From this information, scientists can determine what percentage of the element originated in the bomb itself rather than the environment. To this end, element concentrations in soils from sixty-nine different cities are given, along with activity concentrations for uranium, thorium, potassium, and radium in various building materials. These data are used in the analysis program Python.

  13. Evaluated Nuclear Data

    SciTech Connect

    Oblozinsky, P.; Oblozinsky,P.; Herman,M.; Mughabghab,S.F.

    2010-10-01

    This chapter describes the current status of evaluated nuclear data for nuclear technology applications. We start with evaluation procedures for neutron-induced reactions focusing on incident energies from the thermal energy up to 20 MeV, though higher energies are also mentioned. This is followed by examining the status of evaluated neutron data for actinides that play dominant role in most of the applications, followed by coolants/moderators, structural materials and fission products. We then discuss neutron covariance data that characterize uncertainties and correlations. We explain how modern nuclear evaluated data libraries are validated against an extensive set of integral benchmark experiments. Afterwards, we briefly examine other data of importance for nuclear technology, including fission yields, thermal neutron scattering and decay data. A description of three major evaluated nuclear data libraries is provided, including the latest version of the US library ENDF/B-VII.0, European JEFF-3.1 and Japanese JENDL-3.3. A brief introduction is made to current web retrieval systems that allow easy access to a vast amount of up-to-date evaluated nuclear data for nuclear technology applications.

  14. Nuclear Material Management Abstract

    SciTech Connect

    Jesse C. Schreiber

    2007-07-10

    Nevada Test Site (NTS) has transitioned from its historical and critical role of weapons testing to another critical role for the nation. This new role focuses on being a integral element in solving the multiple challenges facing the National Nuclear Security Administration (NNSA) with nuclear material management. NTS is positioned to be a solution for other NNSA sites challenged with safe nuclear materials storage and disposition. NNSA, with site involvement, is currently transforming the nuclear stockpile and supporting infrastructure to meet the 2030 vision. Efforts are under way to consolidate and modernize the production complex . With respect to the nuclear material stockpile, the NNSA sites are currently reducing the complex nuclear material inventory through disposition and consolidation. This includes moving material from other sites to NTS. State of the art nuclear material management and control practices at NTS are essential for NTS to ensure that assigned activities are accomplished in a safe, secure, efficient, and environmentally responsible manner. NTS activities and challenges will be addressed.

  15. The new nuclear nations

    SciTech Connect

    Spector, L.

    1985-01-01

    Using 251 pages of text, 66 pages of references and 26 pages of appendixes, Spector delves into a world of new nuclear suppliers whose voracious hunger for profits may lead them to provide unwise assistance to countries that are unduly interested in nuclear weaponry. He assails a new dragon, a 'nuclear netherworld' that would illicitly supply such items for profit or political gain. Spector's book tells of covert dealings in nuclear technologies and materials. For him, the buyers have but one goal: '... to gain possession of the knowledge and materials necessary for development of nuclear weapons'. He warns of dangers from this illicit trade, of the loopholes in existing controls and the need to close them. His warnings come wrapped in stories of undercover transactions, many about Pakistan's efforts to get what it needs for its centrifuge enrichment plant. Recognizing the tightening of controls over nuclear trade since the 1970s, including those for dual-use items, Spector is nonetheless pessimistic that these efforts are sufficient to irradicate the nuclear netherworld or to deter newcomers from it.

  16. Perspectives of Nuclear Physics

    NASA Astrophysics Data System (ADS)

    Faessler, Amand

    2003-04-01

    The organizers of this meeting have asked me to present perspectives of nuclear physics. This means to identify the areas where nuclear physics will be expanding in the next future. In six chapters a short overview of these areas will be given, where I expect that nuclear physics will develop quite fast: (1) Quantum Chromodynamics and effective field theories in the confinement region. (2) Nuclear structure at the limits. (3) High energy heavy ion collisions. (4) Nuclear astrophysics. (5) Neutrino physics. (6) Test of physics beyond the standard model by rare processes. After a survey over these six points I will pick out a few topics where I will go more in details. There is no time to give for all six points detailed examples. I shall discuss the following examples of the six topics mentionned above: (1) The perturbative chiral quark model and the nucleon Σ-term. (2) VAMPIR (Variation After Mean field Projection In Realistic model spaces and with realistic forces) as an example of the nuclear structure renaissance. (3) Measurement of important astrophysical nuclear reactions in the Gamow peak. (4) The solar neutrino problem. As examples for testing new physics beyond the standard model by rare processes I had prepared to speak about the measurement of the electric neutron dipole moment and of the neutrinoless double beta decay. But the time is limited and so I have to skip these points, although they are extremely interesting.

  17. American Society of Nuclear Cardiology

    MedlinePlus

    ... much more! class="box-li"> Journal of Nuclear Cardiology Official publication of the American Society of Nuclear Cardiology Clinical Guidelines Procedures, Appropriate Use Criteria, Information Statements ...

  18. Virtual nuclear weapons

    SciTech Connect

    Pilat, J.F.

    1997-08-01

    The term virtual nuclear weapons proliferation and arsenals, as opposed to actual weapons and arsenals, has entered in recent years the American lexicon of nuclear strategy, arms control, and nonproliferation. While the term seems to have an intuitive appeal, largely due to its cyberspace imagery, its current use is still vague and loose. The author believes, however, that if the term is clearly delineated, it might offer a promising approach to conceptualizing certain current problems of proliferation. The first use is in a reference to an old problem that has resurfaced recently: the problem of growing availability of weapon-usable nuclear materials in civilian nuclear programs along with materials made `excess` to defense needs by current arms reduction and dismantlement. It is argued that the availability of these vast materials, either by declared nuclear-weapon states or by technologically advanced nonweapon states, makes it possible for those states to rapidly assemble and deploy nuclear weapons. The second use has quite a different set of connotations. It is derived conceptually from the imagery of computer-generated reality. In this use, one thinks of virtual proliferation and arsenals not in terms of the physical hardware required to make the bomb but rather in terms of the knowledge/experience required to design, assemble, and deploy the arsenal. Virtual weapons are a physics reality and cannot be ignored in a world where knowledge, experience, materials, and other requirements to make nuclear weapons are widespread, and where dramatic army reductions and, in some cases, disarmament are realities. These concepts are useful in defining a continuum of virtual capabilities, ranging from those at the low end that derive from general technology diffusion and the existence of nuclear energy programs to those at the high end that involve conscious decisions to develop or maintain militarily significant nuclear-weapon capabilities.

  19. Monitoring international nuclear activity

    SciTech Connect

    Firestone, R.B.

    2006-05-19

    The LBNL Table of Isotopes website provides primary nuclearinformation to>150,000 different users annually. We have developedthe covert technology to identify users by IP address and country todetermine the kinds of nuclear information they are retrieving. Wepropose to develop pattern recognition software to provide an earlywarning system to identify Unusual nuclear activity by country or regionSpecific nuclear/radioactive material interests We have monitored nuclearinformation for over two years and provide this information to the FBIand LLNL. Intelligence is gleaned from the website log files. Thisproposal would expand our reporting capabilities.

  20. Advances in Nuclear Energy

    NASA Astrophysics Data System (ADS)

    Frois, B.

    2005-04-01

    This paper briefly reviews the next generations of nuclear reactors and the perspectives of development of nuclear energy. Advanced reactors will progressively replace the existing ones during the next two decades. Future systems of the fourth generation are planned to be built beyond 2030. These systems have been studied in the framework of the "Generation IV" International Forum. The goals of these systems is to have a considerable increase in safety, be economically competitive and produce a significantly reduced volume of nuclear wastes. The closed fuel cycle is preferred.

  1. Nuclear Cryogenic Propulsion Stage

    NASA Technical Reports Server (NTRS)

    Houts, Michael G.; Borowski, S. K.; George, J. A.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Adams, R. B.

    2012-01-01

    The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced NEP.

  2. Nuclear power after Chernobyl.

    PubMed

    Ahearne, J F

    1987-05-01

    The causes and progress of the accident at Chernobyl are described, and a comparison between the Chernobyl accident and the 1979 accident at the Three Mile Island nuclear power station is made. Significant similarities between Chernobyl and Three Mile Island include complacency of operators and industry, deliberate negation of safety systems, and a lack of understanding of their plant on the part of the operators, which shows the critical importance of the human element. The Chernobyl accident has implications for nuclear power in the United States; it will affect the research program of the Nuclear Regulatory Commission, regulation of Department of Energy reactors, new reactor designs, and public attitudes. PMID:3576192

  3. Fictions of nuclear disaster

    SciTech Connect

    Dowling, D.

    1987-01-01

    This work is critical study of literary interpretations of the nuclear holocaust. The author examines more than 250 stories and novels dealing with the theme of nuclear power and its devastating potential implications. Addressing such topics as the scientist and Armageddon, the role of religion, future evolution and mutation, and the postnuclear society, the author assesses the response of Bradbury, Lessing, Malamud, Shute, Huxley, Vonnegut, Heinlein, and others to the threat of nuclear apocalypse, with in-depth analyses of Alter Miller's A canticle for Leibowitz and Russell Hoban's Riddley Walker.

  4. Nuclear Medicine Annual, 1989

    SciTech Connect

    Freeman, L.M.; Weissmann, H.S.

    1989-01-01

    Among the highlights of Nuclear Medicine Annual, 1989 are a status report on the thyroid scan in clinical practice, a review of functional and structural brain imaging in dementia, an update on radionuclide renal imaging in children, and an article outlining a quality assurance program for SPECT instrumentation. Also included are discussions on current concepts in osseous sports and stress injury scintigraphy and on correlative magnetic resonance and radionuclide imaging of bone. Other contributors assess the role of nuclear medicine in clinical decision making and examine medicolegal and regulatory aspects of nuclear medicine.

  5. Nuclear regulation and safety

    SciTech Connect

    Hendrie, J.M.

    1982-01-01

    Nuclear regulation and safety are discussed from the standpoint of a hypothetical country that is in the process of introducing a nuclear power industry and setting up a regulatory system. The national policy is assumed to be in favor of nuclear power. The regulators will have responsibility for economic, reliable electric production as well as for safety. Reactor safety is divided into three parts: shut it down, keep it covered, take out the afterheat. Emergency plans also have to be provided. Ways of keeping the core covered with water are discussed. (DLC)

  6. Nuclear lipid droplets: a novel nuclear domain.

    PubMed

    Layerenza, J P; González, P; García de Bravo, M M; Polo, M P; Sisti, M S; Ves-Losada, A

    2013-02-01

    We investigated nuclear neutral-lipid (NL) composition and organization, as NL may represent an alternative source for providing fatty acids and cholesterol (C) to membranes, signaling paths, and transcription factors in the nucleus. We show here that nuclear NL were organized into nonpolar domains in the form of nuclear-lipid droplets (nLD). By fluorescent confocal microscopy, representative nLD were observed in situ within the nuclei of rat hepatocytes in vivo and HepG2 cells, maintained under standard conditions in culture, and within nuclei isolated from rat liver. nLD were resistant to Triton X-100 and became stained with Sudan Red, OsO4, and BODIPY493/503. nLD and control cytosolic-lipid droplets (cLD) were isolated from rat-liver nuclei and from homogenates, respectively, by sucrose-gradient sedimentation. Lipids were extracted, separated by thin-layer chromatography, and quantified. nLD were composed of 37% lipids and 63% proteins. The nLD lipid composition was as follows: 19% triacylglycerols (TAG), 39% cholesteryl esters, 27% C, and 15% polar lipids; whereas the cLD composition contained different proportions of these same lipid classes, in particular 91% TAG. The TAG fatty acids from both lipid droplets were enriched in oleic, linoleic, and palmitic acids. The TAG from the nLD corresponded to a small pool, whereas the TAG from the cLD constituted the main cellular pool (at about 100% yield from the total homogenate). In conclusion, nLD are a domain within the nucleus where NL are stored and organized and may be involved in nuclear lipid homeostasis. PMID:23098923

  7. Nuclear Technology Series. Course 23: Nuclear Chemical Processes.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This technical specialty course is one of thirty-five courses designed for use by two-year postsecondary institutions in five nuclear technician curriculum areas: (1) radiation protection technician, (2) nuclear instrumentation and control technician, (3) nuclear materials processing technician, (4) nuclear quality-assurance/quality-control…

  8. Nuclear Technology Series. Course 5: Introduction to Nuclear Systems.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This technical specialty course is one of thirty-five courses designed for use by two-year postsecondary institutions in five nuclear technician curriculum areas: (1) radiation protection technician, (2) nuclear instrumentation and control technician, (3) nuclear materials processing technician, (4) nuclear quality-assurance/quality-control…

  9. Nuclear Technology Series. Course 24: Nuclear Systems and Safety.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This technical specialty course is one of thirty-five courses designed for use by two-year postsecondary institutions in five nuclear technician curriculum areas: (1) radiation protection technician, (2) nuclear instrumentation and control technician, (3) nuclear materials processing technician, (4) nuclear quality-assurance/quality-control…

  10. After nuclear war - a nuclear winter

    SciTech Connect

    Tangley, L.

    1984-01-01

    The environmental and biological consequences of nuclear war were discussed by more than 100 eminent biologists, physicists and atmospheric scientists at the recent World after Nuclear War conference. The long-term effects were determined to be worse than the well-known immediate effects. They predicted that 225 million tons of smoke would be generated within a few days in their baseline scenario. As a result, the amount of sunlight reaching the earth would be reduced to a few percent of normal and temperatures would fall to -23/sup 0/C. About 30% of the northern middle latitudes would receive more than 250 rads radiation dose for several months and about 50% of the land area would receive more than 100 rads. Dangerous levels of solar ultraviolet light would burn through the atmosphere. It was also determined that these effects would be felt in the southern hemisphere. Those who survived the blast, fire and prompt radiation would face starvation from shutdown of plant photosynthesis and inhibition of phytoplankton photosynthesis. Huge wildfires and acid rains would stress any surviving plants and animals. Conference participants agreed that scientists had taken a new and significant step toward understanding the full consequences of nuclear war.

  11. Nuclear data interface retrospective

    SciTech Connect

    Gray, Mark G

    2008-01-01

    The Nuclear Data Interface (NDI) code library and data formats are the standards for multigroup nuclear data at Los Alamos National Laboratory. NDI's analysis, design, implementation, testing, integration, and maintenance required a ten person-year and ongoing effort by the Nuclear Data Team. Their efforts provide a unique, contemporary experience in producing a standard component library. In reflection upon that experience at NDI's decennial, we have identified several factors critical to NDI's success: it addressed real problems with appropriate simplicity, it fully supported all users, it added extra value through the code to the raw nuclear data, and its team went the distance from analysis through maintenance. In this report we review these critical success factors and discuss their implications for future standardization projects.

  12. Physics and nuclear power

    NASA Astrophysics Data System (ADS)

    Buttery, N. E.

    2008-03-01

    Nuclear power owes its origin to physicists. Fission was demonstrated by physicists and chemists and the first nuclear reactor project was led by physicists. However as nuclear power was harnessed to produce electricity the role of the engineer became stronger. Modern nuclear power reactors bring together the skills of physicists, chemists, chemical engineers, electrical engineers, mechanical engineers and civil engineers. The paper illustrates this by considering the Sizewell B project and the role played by physicists in this. This covers not only the roles in design and analysis but in problem solving during the commissioning of first of a kind plant. Looking forward to the challenges to provide sustainable and environmentally acceptable energy sources for the future illustrates the need for a continuing synergy between physics and engineering. This will be discussed in the context of the challenges posed by Generation IV reactors.

  13. Nuclear plants - military hostages

    SciTech Connect

    Ramberg, B.

    1986-03-01

    Recent events suggest that nuclear reactors could make tempting military or terrorist targets. Despite the care with which most reactors are built, studies document their vulnerability to willful destruction through disruption of coolant mechanisms both inside and outside the containment building. In addition to reactors, such nuclear support facilities as fuel fabrication, reprocessing, and waste storage installations may be attractive military targets. A nuclear bomb which exploded in the vicinity of a reactor could increase its lethal effects by one-third. The implications of this is vulnerability for Middle East stability as well as to other volatile regions. The author suggests several avenues for controlling the dangers: international law, military and civil defense, facility siting, increasing plant safety, and the international management of nuclear energy. 21 references.

  14. Modeling nuclear explosion

    NASA Astrophysics Data System (ADS)

    Redd, Jeremy; Panin, Alexander

    2012-10-01

    As a result of the Nuclear Test Ban Treaty, no nuclear explosion tests have been performed by the US since 1992. This appreciably limits valuable experimental data needed for improvement of existing weapons and development of new ones, as well as for use of nuclear devices in non-military applications (such as making underground oil reservoirs or compressed air energy storages). This in turn increases the value of numerical modeling of nuclear explosions and of their effects on the environment. We develop numerical codes simulating fission chain reactions in a supercritical U and Pu core and the dynamics of the subsequent expansion of generated hot plasma in order to better understand the impact of such explosions on their surroundings. The results of our simulations (of both above ground and underground explosions) of various energy yields are presented.

  15. Desalting and Nuclear Energy

    ERIC Educational Resources Information Center

    Burwell, Calvin C.

    1971-01-01

    Future use of nuclear energy to produce electricity and desalted water is outlined. Possible desalting processes are analyzed to show economic feasibility and the place in planning in world's economic growth. (DS)

  16. JPRS report, nuclear developments

    SciTech Connect

    1991-03-28

    This report contains articles concerning the nuclear developments of the following countries: (1) China; (2) Japan, North Korea, South Korea; (3) Bulgaria; (4) Argentina, Brazil, Honduras; (5) India, Iran, Pakistan, Syria; (6) Soviet Union; and (7) France, Germany, Turkey.

  17. Western Nuclear Science Alliance

    SciTech Connect

    Steve Reese; George Miller; Stephen Frantz; Denis Beller; Denis Beller; Ed Morse; Melinda Krahenbuhl; Bob Flocchini; Jim Elliston

    2010-12-07

    The primary objective of the INIE program is to strengthen nuclear science and engineering programs at the member institutions and to address the long term goal of the University Reactor Infrastructure and Education Assistance Program.

  18. Nuclear material operations manual

    SciTech Connect

    Tyler, R.P.

    1981-02-01

    This manual provides a concise and comprehensive documentation of the operating procedures currently practiced at Sandia National Laboratories with regard to the management, control, and accountability of nuclear materials. The manual is divided into chapters which are devoted to the separate functions performed in nuclear material operations-management, control, accountability, and safeguards, and the final two chapters comprise a document which is also issued separately to provide a summary of the information and operating procedures relevant to custodians and users of radioactive and nuclear materials. The manual also contains samples of the forms utilized in carrying out nuclear material activities. To enhance the clarity of presentation, operating procedures are presented in the form of playscripts in which the responsible organizations and necessary actions are clearly delineated in a chronological fashion from the initiation of a transaction to its completion.

  19. What Is Nuclear Medicine?

    MedlinePlus

    ... known as cosmic radiation, is in the upper atmosphere due to solar and galactic emissions. A typical ... used in medical procedures. 4 Cosmic Radiation Sun - - + - Atmosphere - + +- + + Earth How many nuclear medicine procedures are performed ...

  20. International Nuclear Security

    SciTech Connect

    Doyle, James E.

    2012-08-14

    This presentation discusses: (1) Definitions of international nuclear security; (2) What degree of security do we have now; (3) Limitations of a nuclear security strategy focused on national lock-downs of fissile materials and weapons; (4) What do current trends say about the future; and (5) How can nuclear security be strengthened? Nuclear security can be strengthened by: (1) More accurate baseline inventories; (2) Better physical protection, control and accounting; (3) Effective personnel reliability programs; (4) Minimize weapons-usable materials and consolidate to fewer locations; (5) Consider local threat environment when siting facilities; (6) Implement pledges made in the NSS process; and (7) More robust interdiction, emergency response and special operations capabilities. International cooperation is desirable, but not always possible.

  1. Nuclear air cleaning

    SciTech Connect

    Bellamy, R.R.

    1994-12-31

    This report briefly describes the history of the use of high- efficiency particulate air filters for air cleaning at nuclear installations in the United States and discusses future uses of such filters.

  2. Nuclear Fuel Reprocessing

    SciTech Connect

    Michael F. Simpson; Jack D. Law

    2010-02-01

    This is an a submission for the Encyclopedia of Sustainable Technology on the subject of Reprocessing Spent Nuclear Fuel. No formal abstract was required for the article. The full article will be attached.

  3. Direct nuclear pumped laser

    DOEpatents

    Miley, George H.; Wells, William E.; DeYoung, Russell J.

    1978-01-01

    There is provided a direct nuclear pumped gas laser in which the lasing mechanism is collisional radiated recombination of ions. The gas laser active medium is a mixture of the gases, with one example being neon and nitrogen.

  4. Nuclear magnetic resonance gyroscope

    SciTech Connect

    Grover, B.C.

    1984-02-07

    A nuclear magnetic resonance gyro using two nuclear magnetic resonance gases, preferably xenon 129 and xenon 131, together with two alkaline metal vapors, preferably rubidium, potassium or cesium, one of the two alkaline metal vapors being pumped by light which has the wavelength of that alkaline metal vapor, and the other alkaline vapor being illuminated by light which has the wavelength of that other alkaline vapor.

  5. The nuclear matter problem

    SciTech Connect

    Carlson, J. A.; Cowell, S.; Morales, J.; Ravenhall, D. G.; Pandharipande, V. R.

    2002-01-01

    We review the present statiis of the many-body theory of nuclear and pure neutron matter based on realistic models of nuclear forces, The current models of two- and three-nucleon interactions are discussed along with recent results obtained with the Brueckner and variatioual methods. New initiatives in the variational method and quantuni Monte Carlo nicthods to study pure neutron matter are described, and finally, the analytic behavior of the energy of piire neutron matter at low densities is cliscussed.

  6. Principles of nuclear geology

    SciTech Connect

    Aswathanarayana, U.

    1985-01-01

    This book treats the basic principles of nuclear physics and the mineralogy, geochemistry, distribution and ore deposits of uranium and thorium. The application of nuclear methodology in radiogenic heat and thermal regime of the earth, radiometric prospecting, isotopic age dating, stable isotopes and cosmic-ray produced isotopes is covered. Geological processes, such as metamorphic chronology, petrogenesis, groundwater movement, and sedimentation rate are focussed on.

  7. Nuclear Plant Inspection

    NASA Astrophysics Data System (ADS)

    1983-01-01

    Engineers from the Power Authority of the State of New York use a Crack Growth Analysis Program supplied by COSMIC (Computer Software Management and Information Center) in one stage of nuclear plant inspection. Welds of the nuclear steam supply system are checked for cracks; radiographs, dye penetration and visual inspections are performed to locate cracks in the metal structure and welds. The software package includes three separate crack growth analysis models and enables necessary repairs to be planned before serious problems develop.

  8. Nuclear Fuel Cycle

    SciTech Connect

    Dale, Deborah J.

    2014-10-28

    These slides will be presented at the training course “International Training Course on Implementing State Systems of Accounting for and Control (SSAC) of Nuclear Material for States with Small Quantity Protocols (SQP),” on November 3-7, 2014 in Santa Fe, New Mexico. The slides provide a basic overview of the Nuclear Fuel Cycle. This is a joint training course provided by NNSA and IAEA.

  9. Internet - a nuclear update

    SciTech Connect

    Slone, B.J. III; Richardson, C.E.; Buck, B.L.

    1994-12-31

    Although the connection rate is slow, new nuclear utility Internet connections are being made. However, the rate of information exchange has not grown. To expedite connections, individuals are obtaining their own Internet accounts to support job-related and personal needs. The nuclear industry should increase its use of Internet to share information and access information from on-line servers. A coordinated industry effort should be made to expedite additional utility connections and provide a server system for information exchange.

  10. Nuclear fuel element

    DOEpatents

    Meadowcroft, Ronald Ross; Bain, Alastair Stewart

    1977-01-01

    A nuclear fuel element wherein a tubular cladding of zirconium or a zirconium alloy has a fission gas plenum chamber which is held against collapse by the loops of a spacer in the form of a tube which has been deformed inwardly at three equally spaced, circumferential positions to provide three loops. A heat resistant disc of, say, graphite separates nuclear fuel pellets within the cladding from the plenum chamber. The spacer is of zirconium or a zirconium alloy.

  11. Nuclear and radiochemical analysis

    SciTech Connect

    Ehmann, W.D.; Yates, S.W.

    1988-06-15

    In this, their second fundamental review under the present authorship and title, they have chosen to continue their emphasis on topics representing the use of nuclear properties for chemical analysis. Excluded are topics in the areas of health physics, nuclear spectroscopy (unless directly related to analysis), nuclear engineering, fusion, radioactive waste disposal, fallout, and nuclear and particle physics. Other topics such as particle-induced X-ray emission (PIXE), plasma desorption mass spectrometry, radioimmunoassay, Moessbauer spectroscopy, nuclear dating methods, and radiotracer applications are treated briefly here, since they are adequately covered in other current reviews in this or other major journals. Only a brief mention is made of well logging, since many of the advances in this field do not currently appear in the open literature. As in their previous review, they finish with short comments on some interesting developments in nuclear and radiochemistry that are not strictly analytical in nature. This review is based largely on a computerized keyword search of Chemical Abstracts (CA) for the period from mid-November 1985 through December 31, 1987.

  12. Superpower nuclear minimalism

    SciTech Connect

    Graben, E.K.

    1992-01-01

    During the Cold War, the United States and the Soviet Union competed in building weapons -- now it seems like America and Russia are competing to get rid of them the fastest. The lengthy process of formal arms control has been replaced by exchanges of unilateral force reductions and proposals for reciprocal reductions not necessarily codified by treaty. Should superpower nuclear strategies change along with force postures President Bush has yet to make a formal pronouncement on post-Cold War American nuclear strategy, and it is uncertain if the Soviet/Russian doctrine of reasonable sufficiency formulated in the Gorbachev era actually heralds a change in strategy. Some of the provisions in the most recent round of unilateral proposals put forth by Presidents Bush and Yeltsin in January 1992 are compatible with a change in strategy. Whether such a change has actually occurred remains to be seen. With the end of the Cold War and the breakup of the Soviet Union, the strategic environment has fundamentally changed, so it would seem logical to reexamine strategy as well. There are two main schools of nuclear strategic thought: a maximalist school, mutual assured destruction (MAD) which emphasizes counterforce superiority and nuclear war- fighting capability, and a MAD-plus school, which emphasizes survivability of an assured destruction capability along with the ability to deliver small, limited nuclear attacks in the event that conflict occurs. The MAD-plus strategy is based on an attempt to conventionalize nuclear weapons which is unrealistic.

  13. Nuclear transmutation in steels

    NASA Astrophysics Data System (ADS)

    Belozerova, A. R.; Shimanskii, G. A.; Belozerov, S. V.

    2009-05-01

    The investigations of the effects of nuclear transmutation in steels that are widely used in nuclear power and research reactors and in steels that are planned for the application in thermonuclear fusion plants, which are employed under the conditions of a prolonged action of neutron irradiation with different spectra, made it possible to study the effects of changes in the isotopic and chemical composition on the tendency of changes in the structural stability of these steels. For the computations of nuclear transmutation in steels, we used a program complex we have previously developed on the basis of algorithms for constructing branched block-type diagrams of nuclide transformations and for locally and globally optimizing these diagrams with the purpose of minimizing systematic errors in the calculation of nuclear transmutation. The dependences obtained were applied onto a Schaeffler diagram for steels used for structural elements of reactors. For the irradiation in fission reactors, we observed only a weak influence of the effects of nuclear transmutation in steels on their structural stability. On the contrary, in the case of irradiation with fusion neutrons, a strong influence of the effects of nuclear transmutation in steels on their structural stability has been noted.

  14. Nuclear War and Science Teaching.

    ERIC Educational Resources Information Center

    Hobson, Art

    1983-01-01

    Suggests that science-related material on nuclear war be included in introductory courses. Lists nuclear war topics for physics, psychology, sociology, biology/ecology, chemistry, geography, geology/meteorology, mathematics, and medical science. Also lists 11 lectures on nuclear physics which include nuclear war topics. (JN)

  15. Thinking About Preventing Nuclear War.

    ERIC Educational Resources Information Center

    Ground Zero, Washington, DC.

    Potential paths to nuclear war and the available means of prevention of nuclear war are discussed. Presented is a detailed description of six nuclear war scenarios, and brief examples of types of potential deterrents to nuclear war (firebreaks) which are relevant for each. To be effective, the right combination of firebreaks must be used, the…

  16. 78 FR 50458 - Entergy Nuclear Operations, Inc., James A. Fitzpatrick Nuclear Power Plant, Vermont Yankee...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-19

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Entergy Nuclear Operations, Inc., James A. Fitzpatrick Nuclear Power Plant, Vermont Yankee Nuclear Power Station, Pilgrim Nuclear Power Station, Request for Action AGENCY: Nuclear Regulatory...

  17. Panel report: nuclear physics

    SciTech Connect

    Carlson, Joseph A; Hartouni, Edward P

    2010-01-01

    Nuclear science is at the very heart of the NNSA program. The energy produced by nuclear processes is central to the NNSA mission, and nuclear reactions are critical in many applications, including National Ignition Facility (NIF) capsules, energy production, weapons, and in global threat reduction. Nuclear reactions are the source of energy in all these applications, and they can also be crucial in understanding and diagnosing the complex high-energy environments integral to the work of the NNSA. Nuclear processes are complex quantum many-body problems. Modeling and simulation of nuclear reactions and their role in applications, coupled tightly with experiments, have played a key role in NNSA's mission. The science input to NNSA program applications has been heavily reliant on experiment combined with extrapolations and physical models 'just good enough' to provide a starting point to extensive engineering that generated a body of empirical information. This body of information lacks the basic science underpinnings necessary to provide reliable extrapolations beyond the domain in which it was produced and for providing quantifiable error bars. Further, the ability to perform additional engineering tests is no longer possible, especially those tests that produce data in the extreme environments that uniquely characterize these applications. The end of testing has required improvements to the predictive capabilities of codes simulating the reactions and associated applications for both well known and well characterized cases as well as incompletely known cases. Developments in high performance computing, computational physics, applied mathematics and nuclear theory have combined to make spectacular advances in the theory of fission, fusion and nuclear reactions. Current research exploits these developments in a number of Office of Science and NNSA programs, and in joint programs such as the SciDAC (Science Discovery through Advanced Computing) that supports the

  18. Nuclear powerplants for mobile applications.

    NASA Technical Reports Server (NTRS)

    Anderson, J. L.

    1972-01-01

    Mobile nuclear powerplants for applications other than large ships and submarines will require compact, lightweight reactors with especially stringent impact-safety design. This paper examines the technical and economic feasibility that the broadening role of civilian nuclear power, in general, (land-based nuclear electric generating plants and nuclear ships) can extend to lightweight, safe mobile nuclear powerplants. The paper discusses technical experience, identifies potential sources of technology for advanced concepts, cites the results of economic studies of mobile nuclear powerplants, and surveys future technical capabilities needed by examining the current use and projected needs for vehicles, machines, and habitats that could effectively use mobile nuclear reactor powerplants.

  19. Nuclear Regulatory Commission information digest

    SciTech Connect

    None,

    1990-03-01

    The Nuclear Regulatory Commission information digest provides summary information regarding the US Nuclear Regulatory Commission, its regulatory responsibilities, and areas licensed by the commission. This is an annual publication for the general use of the NRC Staff and is available to the public. The digest is divided into two parts: the first presents an overview of the US Nuclear Regulatory Commission and the second provides data on NRC commercial nuclear reactor licensees and commercial nuclear power reactors worldwide.

  20. NESST: A nuclear energy safety and security treaty-Separating nuclear energy from nuclear weapons

    NASA Astrophysics Data System (ADS)

    McNamara, Brendan

    2012-06-01

    Fission and Fusion energy is matched by the need to completely separate civilian energy programmes from the production of nuclear weapons. The Nuclear Proliferation Treaty (NPT, 1968) muddles these issues together. The case is presented here for making a new Nuclear Energy Security Treaty (NESST) which is rigorous, enforceable without violence, and separate from the political quagmire of nuclear weapons.

  1. Model Action Plan for Nuclear Forensics and Nuclear Attribution

    SciTech Connect

    Dudder, G B; Niemeyer, S; Smith, D K; Kristo, M J

    2004-03-01

    Nuclear forensics and nuclear attribution have become increasingly important tools in the fight against illegal trafficking in nuclear and radiological materials. This technical report documents the field of nuclear forensics and nuclear attribution in a comprehensive manner, summarizing tools and procedures that have heretofore been described independently in the scientific literature. This report also provides national policy-makers, decision-makers, and technical managers with guidance for responding to incidents involving the interdiction of nuclear and radiological materials. However, due to the significant capital costs of the equipment and the specialized expertise of the personnel, work in the field of nuclear forensics has been restricted so far to a handful of national and international laboratories. In fact, there are a limited number of specialists who have experience working with interdicted nuclear materials and affiliated evidence. Most of the laboratories that have the requisite equipment, personnel, and experience to perform nuclear forensic analysis are participants in the Nuclear Smuggling International Technical Working Group or ITWG (see Section 1.8). Consequently, there is a need to disseminate information on an appropriate response to incidents of nuclear smuggling, including a comprehensive approach to gathering evidence that meets appropriate legal standards and to developing insights into the source and routes of nuclear and radiological contraband. Appendix A presents a ''Menu of Options'' for other Member States to request assistance from the ITWG Nuclear Forensics Laboratories (INFL) on nuclear forensic cases.

  2. Nuclear ``pasta'' formation

    NASA Astrophysics Data System (ADS)

    Schneider, A. S.; Horowitz, C. J.; Hughto, J.; Berry, D. K.

    2013-12-01

    The formation of complex nonuniform phases of nuclear matter, known as nuclear pasta, is studied with molecular dynamics (MD) simulations containing 51200 nucleons. A phenomenological nuclear interaction is used that reproduces the saturation binding energy and density of nuclear matter. Systems are prepared at an initial density of 0.10fm-3 and then the density is decreased by expanding the simulation volume at different rates to densities of 0.01fm-3 or less. An originally uniform system of nuclear matter is observed to form spherical bubbles (“swiss cheese”), hollow tubes, flat plates (“lasagna”), thin rods (“spaghetti”) and, finally, nearly spherical nuclei with decreasing density. We explicitly observe nucleation mechanisms, with decreasing density, for these different pasta phase transitions. Topological quantities known as Minkowski functionals are obtained to characterize the pasta shapes. Different pasta shapes are observed depending on the expansion rate. This indicates nonequilibrium effects. We use this to determine the best ways to obtain lower energy states of the pasta system from MD simulations and to place constraints on the equilibration time of the system.

  3. Nuclear age thinking

    SciTech Connect

    Depastas, A.N.

    1990-01-01

    According to the practicalist school, thinking emerges from activity and each human practice is giving food to its own distinctive kinds of perception, conduct, and perspective of the world. The author, while studying and describing developments after the commencement of the nuclear age in many fields of human behavior and knowledge, including the social sciences, particularly psychology and international politics, became an adherent to the practicalist philosophy when he perceived new relevant thoughts coming to his mind at the same time. Indeed writing is a learning experience. He has, therefore, systematically included these thoughts in the following pages and synoptically characterized them in the title: Nuclear Age Thinking. He considers this kind of thinking as automatic, conscious activity which is gradually influencing our choices and decisions. The author has reservations as regards Albert Einstein's saying that the unleashed power of the atom changed everything save our modes of thinking, because the uncontrollability of nuclear energy is apparently in the subconscious of mankind nowadays, influencing the development of a new mode of thinking, and that is the nuclear age thinking which is the subject of this book. Nuclear age thinking drives from the collective fear of extinction of life on earth due to this new power at man's disposal, and it is not only limited to the change in the conventional meaning of the words war and peace.

  4. Europe's nuclear dominos

    SciTech Connect

    Sharp, J. )

    1993-06-01

    As long as the United States continues to play a leading role in NATO, the incentive for European powers to acquire independent nuclear weapons is virtually zero. Most European power, however, have relatively sophisticated nuclear establishments and could easily manufacture nuclear explosives if they judged that their security required an independent capability. They might judge so if the United States pulls out of Europe and out of NATO. It is the opinion of the author that if the United States withdraws, and if France and Britain insist on maintaining their current status as independent nuclear weapons powers, they will encourage proliferation by example. The likelihood of different countries deciding to manufacture nuclear weapons under these cicumstances is evaluated. The future of NATO is assessed. The conclusions of and future structure of the Conference on Cooperation and Security in Europe (CSCE) is discussed. The impact of United Nations involvement in preventing proliferation is evaluated. Recommendations are proposed for the utilization of existing organizations to deter proliferation in Europe.

  5. Nuclear Lunar Logistics Study

    NASA Technical Reports Server (NTRS)

    1963-01-01

    This document has been prepared to incorporate all presentation aid material, together with some explanatory text, used during an oral briefing on the Nuclear Lunar Logistics System given at the George C. Marshall Space Flight Center, National Aeronautics and Space Administration, on 18 July 1963. The briefing and this document are intended to present the general status of the NERVA (Nuclear Engine for Rocket Vehicle Application) nuclear rocket development, the characteristics of certain operational NERVA-class engines, and appropriate technical and schedule information. Some of the information presented herein is preliminary in nature and will be subject to further verification, checking and analysis during the remainder of the study program. In addition, more detailed information will be prepared in many areas for inclusion in a final summary report. This work has been performed by REON, a division of Aerojet-General Corporation under Subcontract 74-10039 from the Lockheed Missiles and Space Company. The presentation and this document have been prepared in partial fulfillment of the provisions of the subcontract. From the inception of the NERVA program in July 1961, the stated emphasis has centered around the demonstration of the ability of a nuclear rocket to perform safely and reliably in the space environment, with the understanding that the assignment of a mission (or missions) would place undue emphasis on performance and operational flexibility. However, all were aware that the ultimate justification for the development program must lie in the application of the nuclear propulsion system to the national space objectives.

  6. Nuclear concepts/propulsion

    NASA Technical Reports Server (NTRS)

    Miller, Thomas J.

    1993-01-01

    Nuclear thermal and nuclear electric propulsion systems will enable and/or enhance important space exploration missions to the moon and Mars. Current efforts are addressing certain research areas, although NASA and DOE still have much work yet to do. Relative to chemical systems, nuclear thermal propulsion offers the potential of reduced vehicle weight, wider launch windows. and shorter transit times, even without aerobrakes. This would improve crew safety by reducing their exposure to cosmic radiation. Advanced materials and structures will be an important resource in responding to the challenges posed by safety and test facility requirements, environmental concerns, high temperature fuels and the high radiation, hot hydrogen environment within nuclear thermal propulsion systems. Nuclear electric propulsion (NEP) has its own distinct set of advantages relative to chemical systems. These include low resupply mass, the availability of large amounts of onboard electric power for other uses besides propulsion, improved launch windows, and the ability to share technology with surface power systems. Development efforts for NEP reactors will emphasize long life operation of compact designs. This will require designs that provide high fuel burnup and high temperature operation along with personnel and environmental safety.

  7. Pediatric nuclear medicine

    SciTech Connect

    Not Available

    1986-01-01

    This symposium presented the latest techniques and approaches to the proper medical application of radionuclides in pediatrics. An expert faculty, comprised of specialists in the field of pediatric nuclear medicine, discussed the major indications as well as the advantages and potential hazards of nuclear medicine procedures compared to other diagnostic modalities. In recent years, newer radiopharmaceuticals labeled with technetium-99m and other short-lived radionuclides with relatively favorable radiation characteristics have permitted a variety of diagnostic studies that are very useful clinically and carry a substantially lower radiation burden then many comparable X-ray studies. This new battery of nuclear medicine procedures is now widely available for diagnosis and management of pediatric patients. Many recent research studies in children have yielded data concerning the effacacy of these procedures, and current recommendations will be presented by those involved in conducting such studies. Individual papers are processed separately for the Energy Data Base.

  8. Nuclear Parton Distribution Functions

    SciTech Connect

    I. Schienbein, J.Y. Yu, C. Keppel, J.G. Morfin, F. Olness, J.F. Owens

    2009-06-01

    We study nuclear effects of charged current deep inelastic neutrino-iron scattering in the framework of a {chi}{sup 2} analysis of parton distribution functions (PDFs). We extract a set of iron PDFs which are used to compute x{sub Bj}-dependent and Q{sup 2}-dependent nuclear correction factors for iron structure functions which are required in global analyses of free nucleon PDFs. We compare our results with nuclear correction factors from neutrino-nucleus scattering models and correction factors for charged-lepton--iron scattering. We find that, except for very high x{sub Bj}, our correction factors differ in both shape and magnitude from the correction factors of the models and charged-lepton scattering.

  9. Nuclear Power in Space

    DOE R&D Accomplishments Database

    1994-01-01

    In the early years of the United States space program, lightweight batteries, fuel cells, and solar modules provided electric power for space missions. As missions became more ambitious and complex, power needs increased and scientists investigated various options to meet these challenging power requirements. One of the options was nuclear energy. By the mid-1950s, research had begun in earnest on ways to use nuclear power in space. These efforts resulted in the first radioisotope thermoelectric generators (RTGs), which are nuclear power generators build specifically for space and special terrestrial uses. These RTGs convert the heat generated from the natural decay of their radioactive fuel into electricity. RTGs have powered many spacecraft used for exploring the outer planets of the solar system and orbiting the sun and Earth. They have also landed on Mars and the moon. They provide the power that enables us to see and learn about even the farthermost objects in our solar system.

  10. Atlas of Nuclear Isomers

    SciTech Connect

    Jain, Ashok Kumar; Maheshwari, Bhoomika; Garg, Swati; Patial, Monika; Singh, Balraj

    2015-09-15

    We present an atlas of nuclear isomers containing the experimental data for the isomers with a half-life ≥ 10 ns together with their various properties such as excitation-energy, half-life, decay mode(s), spin-parity, energies and multipolarities of emitted gamma transitions, etc. The ENSDF database complemented by the XUNDL database has been extensively used in extracting the relevant data. Recent literature from primary nuclear physics journals, and the NSR bibliographic database have been searched to ensure that the compiled data Table is as complete and current as possible. The data from NUBASE-12 have also been checked for completeness, but as far as possible original references have been cited. Many interesting systematic features of nuclear isomers emerge, some of them new; these are discussed and presented in various graphs and figures. The cutoff date for the extraction of data from the literature is August 15, 2015.

  11. Nuclear transfer in ruminants.

    PubMed

    Lee, Joon-Hee; Maalouf, Walid E

    2015-01-01

    Ruminants were the first mammalian species to be cloned successfully by nuclear transplantation. Those experiments were designed to multiply high merit animals (Willadsen, Nature 320(6057):63-65, 1986; Prather et al., Biol Reprod 37(4):859-866, 1987; Wilmut et al., Nature 385(6619):810-813, 1997). Since then, cloning has provided us with a vast amount of knowledge and information on the reprogramming ability of somatic cells to different cell types which became an important basis for stem cell research and human medicine. Nowadays, the goals of most nuclear transfer work vary widely but in most cases the micromanipulation procedures remain the same. However, differences between species require different technical considerations. In this chapter, we describe in detail somatic cell nuclear transfer which is the foremost method for cloning ruminants with specific reference to sheep and cattle.

  12. Nuclear resonant spectroscopy

    NASA Astrophysics Data System (ADS)

    Sturhahn, Wolfgang

    2004-02-01

    Nuclear resonant scattering techniques with synchrotron radiation (SR) are introduced on a basic level. We focus on the theoretical background and on experimental aspects of two popular methods with a widening range of applications, nuclear resonant inelastic x-ray scattering and synchrotron Mössbauer spectroscopy. The inelastic method provides specific vibrational information, e.g., the phonon density of states. The Mössbauer method permits determination of hyperfine interactions. All nuclear resonance techniques take full advantage of the unique properties of SR: intensity, collimation, time structure, and polarization. As a result both methods discussed here have led to novel applications for materials under extreme conditions, proteins with biological functionality, and magnetic nanostructures.

  13. Nuclear fuel element

    DOEpatents

    Armijo, Joseph S.; Coffin, Jr., Louis F.

    1983-01-01

    A nuclear fuel element for use in the core of a nuclear reactor is disclosed and has a composite cladding having a substrate and a metal barrier metallurgically bonded on the inside surface of the substrate so that the metal barrier forms a shield between the substrate and the nuclear fuel material held within the cladding. The metal barrier forms about 1 to about 30 percent of the thickness of the cladding and is comprised of a low neutron absorption metal of substantially pure zirconium. The metal barrier serves as a preferential reaction site for gaseous impurities and fission products and protects the substrate from contact and reaction with such impurities and fission products. The substrate of the composite cladding is selected from conventional cladding materials and preferably is a zirconium alloy. Methods of manufacturing the composite cladding are also disclosed.

  14. Nuclear fuel element

    DOEpatents

    Armijo, Joseph S.; Coffin, Jr., Louis F.

    1980-04-29

    A nuclear fuel element for use in the core of a nuclear reactor is disclosed and has an improved composite cladding comprised of a moderate purity metal barrier of zirconium metallurgically bonded on the inside surface of a zirconium alloy tube. The metal barrier forms a shield between the alloy tube and a core of nuclear fuel material enclosed in the composite cladding. There is a gap between the cladding and the core. The metal barrier forms about 1 to about 30 percent of the thickness of the composite cladding and has low neutron absorption characteristics. The metal barrier serves as a preferential reaction site for gaseous impurities and fission products and protects the alloy tube from contact and reaction with such impurities and fission products. Methods of manufacturing the composite cladding are also disclosed.

  15. Nuclear explosive safety study process

    SciTech Connect

    1997-01-01

    Nuclear explosives by their design and intended use require collocation of high explosives and fissile material. The design agencies are responsible for designing safety into the nuclear explosive and processes involving the nuclear explosive. The methodology for ensuring safety consists of independent review processes that include the national laboratories, Operations Offices, Headquarters, and responsible Area Offices and operating contractors with expertise in nuclear explosive safety. A NES Study is an evaluation of the adequacy of positive measures to minimize the possibility of an inadvertent or deliberate unauthorized nuclear detonation, high explosive detonation or deflagration, fire, or fissile material dispersal from the pit. The Nuclear Explosive Safety Study Group (NESSG) evaluates nuclear explosive operations against the Nuclear Explosive Safety Standards specified in DOE O 452.2 using systematic evaluation techniques. These Safety Standards must be satisfied for nuclear explosive operations.

  16. Comprehensive Glossary of Nuclear Science

    NASA Astrophysics Data System (ADS)

    Langlands, Tracy; Stone, Craig; Meyer, Richard

    2001-10-01

    We have developed a comprehensive glossary of terms covering the broad fields of nuclear and related areas of science. The glossary has been constructed with two sections. A primary section consists of over 6,000 terms covering the fields of nuclear and high energy physics, nuclear chemistry, radiochemistry, health physics, astrophysics, materials science, analytical science, environmental science, nuclear medicine, nuclear engineering, nuclear instrumentation, nuclear weapons, and nuclear safeguards. Approximately 1,500 terms of specific focus on military and nuclear weapons testing define the second section. The glossary is currently larger than many published glossaries and dictionaries covering the entire field of physics. Glossary terms have been defined using an extensive collection of current and historical publications. Historical texts extend back into the 1800's, the early days of atomic physics. The glossary has been developed both as a software application and as a hard copy document.

  17. Swedish nuclear waste efforts

    SciTech Connect

    Rydberg, J.

    1981-09-01

    After the introduction of a law prohibiting the start-up of any new nuclear power plant until the utility had shown that the waste produced by the plant could be taken care of in an absolutely safe way, the Swedish nuclear utilities in December 1976 embarked on the Nuclear Fuel Safety Project, which in November 1977 presented a first report, Handling of Spent Nuclear Fuel and Final Storage of Vitrified Waste (KBS-I), and in November 1978 a second report, Handling and Final Storage of Unreprocessed Spent Nuclear Fuel (KBS II). These summary reports were supported by 120 technical reports prepared by 450 experts. The project engaged 70 private and governmental institutions at a total cost of US $15 million. The KBS-I and KBS-II reports are summarized in this document, as are also continued waste research efforts carried out by KBS, SKBF, PRAV, ASEA and other Swedish organizations. The KBS reports describe all steps (except reprocessing) in handling chain from removal from a reactor of spent fuel elements until their radioactive waste products are finally disposed of, in canisters, in an underground granite depository. The KBS concept relies on engineered multibarrier systems in combination with final storage in thoroughly investigated stable geologic formations. This report also briefly describes other activities carried out by the nuclear industry, namely, the construction of a central storage facility for spent fuel elements (to be in operation by 1985), a repository for reactor waste (to be in operation by 1988), and an intermediate storage facility for vitrified high-level waste (to be in operation by 1990). The R and D activities are updated to September 1981.

  18. Shoreham Nuclear Power Plant

    SciTech Connect

    1992-12-31

    The United States Supreme Court, with PG&E and Silkwood, and in the eight years since, has expanded the acceptable extent of state regulation of commercial nuclear power plants. In PG&E, the Court established the acceptability of state regulation that purports to be concerned with the non-radiological aspects of nuclear plant operations but that, as a practical matter, is concerned with their radiological hazards. In Silkwood, the Court established the acceptability of state regulation of radiological hazards when its impact on federal regulation of radiological hazards is indirect and incidental. Finally, in Goodyear and English, the Court confirmed and elaborated on such state regulation. Subject to political demands either for additional involvement in commercial nuclear power plant regulation or from political interests opposed altogether to nuclear power, some states, in the 1980s, sought to expand even further the involvement of state and local governments in nuclear plant regulation. Indeed, some states sought and in some instances acquired, through innovative and extraordinary means, a degree of involvement in the regulation of radiological hazards that seriously erodes and undermines the role of the federal government in such regulation. In particular, the State of New York concluded with the Long Island Lighting Company (LILCO), in February 1989, an agreement for the purchase of New York of the Shoreham nuclear power plant on Long Island. A response to failed efforts by New York to prevent the issuance by the NRC of a license to LILCO to operate the plant, the agreement was concluded to allow New York to close the plant either altogether or to convert it to a fossil fuel facility. The opposition to the sale of Shoreham is discussed.

  19. Nuclear structure research

    NASA Astrophysics Data System (ADS)

    Brenner, D. S.

    1992-07-01

    The TRISTAN on-line isotope separator and the capture gamma ray facility at the HFBR are the experimental foci of the program which has four principal research themes, three involving nuclear structure physics and one directed towards astrophysics. These themes are: (1) the manifestation of the proton-neutron interaction in the evolution of nuclear structure and its relation to collectivity; (2) the appearance and the role of symmetries and supersymmetries in nuclei; (3) the study of new regions of magic nuclei; and (4) the characterization of nuclei important in r-process stellar nucleosynthesis.

  20. Introduction to nuclear physics.

    PubMed

    Patton, J A

    1998-01-01

    Photons for counting or imaging applications in nuclear medicine result from several processes. Gamma rays are produced from excited state transitions after beta decay and electron capture. Annihilation photons result from positron decay. The de-excitation of the atom after electron capture results in the production of characteristic x rays or Auger electrons. Metastable state transitions result in gamma ray emission or internal conversion electrons. All radiopharmaceuticals used in diagnostic nuclear medicine applications are tagged with radionuclides that emit photons as a result of one of these processes.

  1. Focused technology: Nuclear propulsion

    NASA Technical Reports Server (NTRS)

    Miller, Thomas J.

    1991-01-01

    The topics presented are covered in viewgraph form and include: nuclear thermal propulsion (NTP), which challenges (1) high temperature fuel and materials, (2) hot hydrogen environment, (3) test facilities, (4) safety, (5) environmental impact compliance, and (6) concept development, and nuclear electric propulsion (NEP), which challenges (1) long operational lifetime, (2) high temperature reactors, turbines, and radiators, (3) high fuel burn-up reactor fuels, and designs, (4) efficient, high temperature power conditioning, (5) high efficiency, and long life thrusters, (6) safety, (7) environmental impact compliance, and (8) concept development.

  2. Nuclear Innovation Workshops Report

    SciTech Connect

    Jackson, John Howard; Allen, Todd Randall; Hildebrandt, Philip Clay; Baker, Suzanne Hobbs

    2015-09-01

    The Nuclear Innovation Workshops were held at six locations across the United States on March 3-5, 2015. The data collected during these workshops has been analyzed and sorted to bring out consistent themes toward enhancing innovation in nuclear energy. These themes include development of a test bed and demonstration platform, improved regulatory processes, improved communications, and increased public-private partnerships. This report contains a discussion of the workshops and resulting themes. Actionable steps are suggested at the end of the report. This revision has a small amount of the data in Appendix C removed in order to avoid potential confusion.

  3. Nuclear propulsion systems engineering

    SciTech Connect

    Madsen, W.W.; Neuman, J.E.: Van Haaften, D.H.

    1992-01-01

    The Nuclear Energy for Rocket Vehicle Application (NERVA) program of the 1960's and early 1970's was dramatically successful, with no major failures during the entire testing program. This success was due in large part to the successful development of a systems engineering process. Systems engineering, properly implemented, involves all aspects of the system design and operation, and leads to optimization of theentire system: cost, schedule, performance, safety, reliability, function, requirements, etc. The process must be incorporated from the very first and continued to project completion. This paper will discuss major aspects of the NERVA systems engineering effort, and consider the implications for current nuclear propulsion efforts.

  4. Nuclear propulsion systems engineering

    SciTech Connect

    Madsen, W.W.; Neuman, J.E.: Van Haaften, D.H.

    1992-12-31

    The Nuclear Energy for Rocket Vehicle Application (NERVA) program of the 1960`s and early 1970`s was dramatically successful, with no major failures during the entire testing program. This success was due in large part to the successful development of a systems engineering process. Systems engineering, properly implemented, involves all aspects of the system design and operation, and leads to optimization of theentire system: cost, schedule, performance, safety, reliability, function, requirements, etc. The process must be incorporated from the very first and continued to project completion. This paper will discuss major aspects of the NERVA systems engineering effort, and consider the implications for current nuclear propulsion efforts.

  5. Neutrinos in Nuclear Physics

    SciTech Connect

    McKeown, Bob

    2015-06-01

    Since the discovery of nuclear beta decay, nuclear physicists have studied the weak interaction and the nature of neutrinos. Many recent and current experiments have been focused on the elucidation of neutrino oscillations and neutrino mass. The quest for the absolute value of neutrino mass continues with higher precision studies of the tritium beta decay spectrum near the endpoint. Neutrino oscillations are studied through measurements of reactor neutrinos as a function of baseline and energy. And experiments searching for neutrinoless double beta decay seek to discover violation of lepton number and establish the Majorana nature of neutrino masses.

  6. Managing nuclear operations

    SciTech Connect

    Carter, A.B.; Steinbruner, J.D.; Zraket, C.A.

    1987-01-01

    This book seeks to remedy the neglect of nuclear operations as a major flaw in the prevailing understanding of security. It aims to make the operational terrain at least more familiar if not much firmer. It describes the instruments involved in nuclear operations - the sensors, communications links, and command centers that form the physical network as well as the plans, procedures, organizations, and widely shared assumptions that allow the parts to work together coherently. The book as a whole seeks more to pose fundamental issues of operations management than to give definitive answers. It promotes no particular policy and makes no recommendations.

  7. Nuclear War Survival Skills

    SciTech Connect

    Kearny, C.H.

    2002-06-24

    The purpose of this book is to provide Americans with information and instructions that will significantly increase their chances of surviving a possible nuclear attack. It brings together field-tested instructions that, if followed by a large fraction of Americans during a crisis that preceded an attack, could save millions of lives. The author is convinced that the vulnerability of our country to nuclear threat or attack must be reduced and that the wide dissemination of the information contained in this book would help achieve that objective of our overall defense strategy.

  8. Friction in nuclear dynamics

    SciTech Connect

    Swiatecki, W.J.

    1985-03-01

    The problem of dissipation in nuclear dynamics is related to the breaking down of nuclear symmetries and the transition from ordered to chaotic nucleonic motions. In the two extreme idealizations of the perfectly Ordered Regime and the fully Chaotic Regime, the nucleus should behave as an elastic solid or an overdamped fluid, respectively. In the intermediate regime a complicated visco-elastic behaviour is expected. The discussion is illustrated by a simple estimate of the frequency of the giant quadrupole resonance in the Ordered Regime and by applications of the wall and window dissipation formulae in the Chaotic Regime. 51 refs.

  9. Nuclear Plant Data Bank

    SciTech Connect

    Booker, C.P.; Turner, M.R.; Spore, J.W.

    1986-01-01

    The Nuclear Plant Data Bank (NPDB) is being developed at the Los Alamos National Laboratory to assist analysts in the rapid and accurate creation of input decks for reactor transient analysis. The NPDB will reduce the time and cost of the creation or modification of a typical input deck. This data bank will be an invaluable tool in the timely investigation of recent and ongoing nuclear reactor safety analysis. This paper discusses the status and plans for the NPDB development and describes its anticipated structure and capabilities.

  10. Nuclear waste's last stand

    SciTech Connect

    Not Available

    1992-12-01

    It's hard to imagine a more unwelcome neighbor than nuclear waste. But something has to be done with the spent fuel now piling up at nuclear plants in the United States. While a handful of Indian tribes and other communities have shown interest in hosting a temporary storage site, the outcry from their neighbors and politicians may squash their plans. Now, a decade after the federal government began the search for a permanent repository, it still can't find even a temporary destination. Here's look at the problem and its consequences.

  11. Nuclear reactor effluent monitoring

    SciTech Connect

    Minns, J.L.; Essig, T.H.

    1993-12-31

    Radiological environmental monitoring and effluent monitoring at nuclear power plants is important both for normal operations, as well as in the event of an accident. During normal operations, environmental monitoring verifies the effectiveness of in-plant measures for controlling the release of radioactive materials in the plant. Following an accident, it would be an additional mechanism for estimating doses to members of the general public. This paper identifies the U.S. Nuclear Regulatory Commission (NRC) regulatory basis for requiring radiological environmental and effluent monitoring, licensee conditions for effluent and environmental monitoring, NRC independent oversight activities, and NRC`s program results.

  12. Nuclear medicine imaging system

    DOEpatents

    Bennett, G.W.; Brill, A.B.; Bizais, Y.J.C.; Rowe, R.W.; Zubal, I.G.

    1983-03-11

    It is an object of this invention to provide a nuclear imaging system having the versatility to do positron annihilation studies, rotating single or opposed camera gamma emission studies, and orthogonal gamma emission studies. It is a further object of this invention to provide an imaging system having the capability for orthogonal dual multipinhole tomography. It is another object of this invention to provide a nuclear imaging system in which all available energy data, as well as patient physiological data, are acquired simultaneously in list mode.

  13. Nuclear physics. Fourth edition

    SciTech Connect

    Wehr, M.R.; Richards, J.A.; Adair, T.W.

    1984-01-01

    This book is designed to be an extension of the introductory college physics course into the realm of atomic physics: It should give students a proficiency in this field comparable to their proficiency in mechanics, heat, sound, light and electricity. Topics included: the atomic view of matter; the atomic view of electricity; the atomic view of radiation; the atomic models of Rutherford and Bohr; relativity; x-rays; waves and particles; quantum mechanics; the atomic view of solids; natural radioactivity; nuclear reactions and artificial radioactivity; nuclear energy; and high-energy physics.

  14. Superheated ice: true compression fractures and fast internal melting.

    PubMed

    Knight, C A; Knight, N C

    1972-11-10

    Internal melt figures can be nucleated in ice without the presence of a vapor bubble. Their form and growth are fracture-like, different from the normal Tyndall stars, which do contain vapor bubbles. Normal Tyndall figures that grow rapidly are not oriented in the basal plane, and very rapid internal melting gives a peculiar, systematic growth of clouds of Tyndall figures. PMID:17793685

  15. Superheated fuel injection for combustion of liquid-solid slurries

    DOEpatents

    Robben, F.A.

    1984-10-19

    A method and device are claimed for obtaining, upon injection, flash evaporation of a liquid in a slurry fuel to aid in ignition and combustion. The device is particularly beneficial for use of coal-water slurry fuels in internal combustion engines such as diesel engines and gas turbines, and in external combustion devices such as boilers and furnaces. The slurry fuel is heated under pressure to near critical temperature in an injector accumulator, where the pressure is sufficiently high to prevent boiling. After injection into a combustion chamber, the water temperature will be well above boiling point at a reduced pressure in the combustion chamber, and flash boiling will preferentially take place at solid-liquid surfaces, resulting in the shattering of water droplets and the subsequent separation of the water from coal particles. This prevents the agglomeration of the coal particles during the subsequent ignition and combustion process, and reduces the energy required to evaporate the water and to heat the coal particles to ignition temperature. The overall effect will be to accelerate the ignition and combustion rates, and to reduce the size of the ash particles formed from the coal. 2 figs., 2 tabs.

  16. Photothermal Superheating of Water with Ion-Implanted Silicon Nanowires

    SciTech Connect

    Roder, Paden B.; Manandhar, Sandeep; Smith, Bennett E.; Zhou, Xuezhe; Shutthanandan, V.; Pauzauskie, Peter J.

    2015-07-21

    Nanoparticle-mediated photothermal (PT) cancer therapy has been a major focus in nanomedicine due to its potential as an effective, non-invasive, and targeted alternative to traditional cancer therapy based on small-molecule pharmaceuticals[1,2]. Gold nanocrystals have been a primary focus of PT research[3], which can be attributed to their size tunability[4], well understood conjugation chemistry[5], and efficient absorption of NIR radiation in the tissue transparency window (800 nm – 1 μm) due to their size-dependent localized surface plasmon resonances[6].

  17. Experimental research of heterogeneous nuclei in superheated steam

    NASA Astrophysics Data System (ADS)

    Bartoš, Ondřej; Kolovratník, Michal; Šmíd, Bohuslav; Hrubý, Jan

    2016-03-01

    A mobile steam expansion chamber has been developed to investigate experimentally homogeneous and heterogeneous nucleation processes in steam, both in the laboratory and at power plants using the steam withdrawn from the steam turbine. The purpose of the device is to provide new insight into the physics of nonequilibrium wet steam formation, which is one of the factors limiting the efficiency and reliability of steam turbines. The expanded steam or a mixture of steam with a non-condensable gas rapidly expands in the expansion chamber. Due to adiabatic cooling, the temperature drops below the dew point of the steam at a given pressure. When reaching a sufficiently high supersaturation, droplets are nucleated. By tuning the supersaturation in the so-called nucleation pulse, particles of various size ranges can be activated. This fact is used in the present study to measure the aerosol particles present in the air. Homogeneous nucleation was negligible in this case. The experiment demonstrates the functionality of the device, data acquisition system and data evaluation methods.

  18. Superheated ice: true compression fractures and fast internal melting.

    PubMed

    Knight, C A; Knight, N C

    1972-11-10

    Internal melt figures can be nucleated in ice without the presence of a vapor bubble. Their form and growth are fracture-like, different from the normal Tyndall stars, which do contain vapor bubbles. Normal Tyndall figures that grow rapidly are not oriented in the basal plane, and very rapid internal melting gives a peculiar, systematic growth of clouds of Tyndall figures.

  19. Superheated fuel injection for combustion of liquid-solid slurries

    DOEpatents

    Robben, Franklin A.

    1985-01-01

    A method and device for obtaining, upon injection, flash evaporation of a liquid in a slurry fuel to aid in ignition and combustion. The device is particularly beneficial for use of coal-water slurry fuels in internal combustion engines such as diesel engines and gas turbines, and in external combustion devices such as boilers and furnaces. The slurry fuel is heated under pressure to near critical temperature in an injector accumulator, where the pressure is sufficiently high to prevent boiling. After injection into a combustion chamber, the water temperature will be well above boiling point at a reduced pressure in the combustion chamber, and flash boiling will preferentially take place at solid-liquid surfaces, resulting in the shattering of water droplets and the subsequent separation of the water from coal particles. This prevents the agglomeration of the coal particles during the subsequent ignition and combustion process, and reduces the energy required to evaporate the water and to heat the coal particles to ignition temperature. The overall effect will be to accelerate the ignition and combustion rates, and to reduce the size of the ash particles formed from the coal.

  20. Safety culture in the nuclear versus non-nuclear organization

    SciTech Connect

    Haber, S.B.; Shurberg, D.A.

    1996-10-01

    The importance of safety culture in the safe and reliable operation of nuclear organizations is not a new concept. The greatest barriers to this area of research are twofold: (1) the definition and criteria of safety culture for a nuclear organization and (2) the measurement of those attributes in an objective and systematic fashion. This paper will discuss a proposed resolution of those barriers as demonstrated by the collection of data across nuclear and non-nuclear facilities over a two year period.

  1. Nuclear effects in Neutrino Nuclear Cross-sections

    SciTech Connect

    Singh, S. K.; Athar, M. Sajjad

    2008-02-21

    Nuclear effects in the quasielastic and inelastic scattering of neutrinos(antineutrinos) from nuclear targets have been studied. The calculations are done in the local density approximation which take into account the effect of nucleon motion as well as renormalisation of weak transition strengths in the nuclear medium. The inelastic reaction leading to production of pions is calculated in a {delta} dominance model taking into account the renormalization of {delta} properties in the nuclear medium.

  2. Nuclear cardiograph and scintigraphy

    NASA Technical Reports Server (NTRS)

    Mclaughlin, P.

    1975-01-01

    Extensive advances in the technology of detectors, data analysis systems, and tracers used have resulted in greatly expanded applications of radioisotopes to the assessment of cardiac function and disease. The development of nuclear cardiology has proceeded along four lines: (1) radionuclide angiography, (2) myocardial perfusion imaging, (3) intracoronary microsphere imaging, and (4) regional myocardial blood flow determination using inert gases.

  3. Nuclear testing: Executive summary

    SciTech Connect

    Drell, S.; Cornwall, J.; Dyson, F.

    1995-08-01

    The authors have examined the experimental and analytic bases for understanding the performance of each of the weapon types that are currently planned to remain in the US enduring nuclear stockpile. They have also examined whether continued underground tests at various nuclear yield thresholds would add significantly to the confidence in this stockpile in the years ahead. The starting point for this examination was a detailed review of past experience in developing and testing modern nuclear weapons, their certification and recertification processes, their performance margins, and evidence of aging or other trends over time for each weapon type in the enduring stockpile. The findings, as summarized in Conclusions 1 through 6, are consistent with US agreement to enter into a Comprehensive Test Ban Treaty (CTBT) of unending duration, that includes a standard ``supreme national interest`` clause. Recognizing that the challenge of maintaining an effective nuclear stockpile for an indefinite period without benefit of underground tests is an important and also a new one, the US should affirm its readiness to invoke the supreme national interest clause should the need arise as a result of unanticipated technical problems in the enduring stockpile.

  4. Nuclear Cluster Physics

    SciTech Connect

    Kamimura, Masayasu

    2011-05-06

    Predictive power of theory needs good models and accurate calculation methods to solve the Schroedinger equations of the systems concerned. We present some examples of successful predictions based on the nuclear cluster models of light nuclei and hypernuclei and on the calculation methods that have been developed by Kyushu group.

  5. Nuclear Reactors and Technology

    SciTech Connect

    Cason, D.L.; Hicks, S.C.

    1992-01-01

    This publication Nuclear Reactors and Technology (NRT) announces on a monthly basis the current worldwide information available from the open literature on nuclear reactors and technology, including all aspects of power reactors, components and accessories, fuel elements, control systems, and materials. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database during the past month. Also included are US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency`s Energy Technology Data Exchange or government-to-government agreements. The digests in NRT and other citations to information on nuclear reactors back to 1948 are available for online searching and retrieval on the Energy Science and Technology Database and Nuclear Science Abstracts (NSA) database. Current information, added daily to the Energy Science and Technology Database, is available to DOE and its contractors through the DOE Integrated Technical Information System. Customized profiles can be developed to provide current information to meet each user`s needs.

  6. Topics in nuclear power

    SciTech Connect

    Budnitz, Robert J.

    2015-03-30

    The 101 nuclear plants operating in the US today are far safer than they were 20-30 years ago. For example, there's been about a 100-fold reduction in the occurrence of 'significant events' since the late 1970s. Although the youngest of currently operating US plants was designed in the 1970s, all have been significantly modified over the years. Key contributors to the safety gains are a vigilant culture, much improved equipment reliability, greatly improved training of operators and maintenance workers, worldwide sharing of experience, and the effective use of probabilistic risk assessment. Several manufacturers have submitted high quality new designs for large reactors to the U.S. Nuclear Regulatory Commission (NRC) for design approval, and several companies are vigorously working on designs for smaller, modular reactors. Although the Fukushima reactor accident in March 2011 in Japan has been an almost unmitigated disaster for the local population due to their being displaced from their homes and workplaces and also due to the land contamination, its 'lessons learned' have been important for the broader nuclear industry, and will surely result in safer nuclear plants worldwide - indeed, have already done so, with more safety improvements to come.

  7. Nuclear waste solutions

    DOEpatents

    Walker, Darrel D.; Ebra, Martha A.

    1987-01-01

    High efficiency removal of technetium values from a nuclear waste stream is achieved by addition to the waste stream of a precipitant contributing tetraphenylphosphonium cation, such that a substantial portion of the technetium values are precipitated as an insoluble pertechnetate salt.

  8. Nuclear and radiochemical analysis

    SciTech Connect

    Ehmann, W.D.; Robertson, J.D.; Yates, S.W.

    1992-06-15

    This is the fourth in a series of periodic reviews on the subject of nuclear and radiochemical analysis. The review covers material found in books and journals concerning radiochemical, neutron activation, charged-particle activation, ion beam, isotope dilution, direct counting, transmission, attenuation, scattering, tracer, and isotopic dating methods.

  9. Children's (Pediatric) Nuclear Medicine

    MedlinePlus

    ... like? Special camera or imaging devices used in nuclear medicine include the gamma camera and single-photon emission-computed tomography (SPECT). The gamma camera, also called a scintillation camera, detects radioactive energy that is emitted from the patient's body and ...

  10. Washington: Hanford Nuclear Reservation

    Atmospheric Science Data Center

    2014-05-15

    ... area around the Hanford Nuclear Reservation near Richland, Washington. On June 27, 2000, a fire in the dry sagebrush was sparked by an ... CA, for NASA's Science Mission Directorate, Washington, D.C. The Terra spacecraft is managed by NASA's Goddard Space Flight Center, ...

  11. NUCLEAR CONVERSION APPARATUS

    DOEpatents

    Seaborg, G.T.

    1960-09-13

    A nuclear conversion apparatus is described which comprises a body of neutron moderator, tubes extending therethrough, uranium in the tubes, a fluid- circulating system associated with the tubes, a thorium-containing fluid coolant in the system and tubes, and means for withdrawing the fluid from the system and replacing it in the system whereby thorium conversion products may be recovered.

  12. Viewpoints on Nuclear Education.

    ERIC Educational Resources Information Center

    Social Education, 1983

    1983-01-01

    The Committee on the Present Danger, Inc., the Committee of Atomic Bomb Survivors in the United States, the World Friendship Center in Hiroshima, two authors, physics and education professors, an English and history teacher, and a high school student comment on nuclear education. (RM)

  13. Second Nuclear Era

    SciTech Connect

    Weinberg, A.M.; Spiewak, I.; Barkenbus, J.N.; Livingston, R.S.; Phung, D.L.

    1984-03-01

    The Institute for Energy Analysis with support from The Andrew W. Mellon Foundation has studied the decline of the present nuclear era in the United States and the characteristics of a Second Nuclear Era which might be instrumental in restoring nuclear power to an appropriate place in the energy options of our country. The study has determined that reactors operating today are much safer than they were at the time of the TMI accident. A number of concepts for a supersafe reactor were reviewed and at least two were found that show considerable promise, the PIUS, a Swedish pressurized water design, and a gas-cooled modular design of German and US origin. Although new, safer, incrementally improved, conventional reactors are under study by the nuclear industry, the complete lack of new orders in the United States will slow their introduction and they are likely to be more expensive than present designs. The study recommends that supersafe reactors be taken seriously and that federal and private funds both be used to design and, if feasible, to build a prototype reactor of substantial size. 146 references, 8 figures, 2 tables.

  14. Nuclear thermal propulsion

    NASA Technical Reports Server (NTRS)

    Bennett, Gary L.

    1991-01-01

    This document is presented in viewgraph form, and the topics covered include the following: (1) the direct fission-thermal propulsion process; (2) mission applications of direct fission-thermal propulsion; (3) nuclear engines for rocket vehicles; (4) manned mars landers; and (5) particle bed reactor design.

  15. Controlled Nuclear Fusion.

    ERIC Educational Resources Information Center

    Glasstone, Samuel

    This publication is one of a series of information booklets for the general public published by The United States Atomic Energy Commission. Among the topics discussed are: Importance of Fusion Energy; Conditions for Nuclear Fusion; Thermonuclear Reactions in Plasmas; Plasma Confinement by Magnetic Fields; Experiments With Plasmas; High-Temperature…

  16. JPRS report, nuclear developments

    SciTech Connect

    1991-03-19

    This report contains articles concerning the nuclear developments of the following countries: (1) China; (2) Japan, North Korea, South Korea, Taiwan; (3) Bulgaria, Czechoslovakia, Yugoslavia; (4) Argentina, Brazil, Panama; (5) India, Iran, Pakistan, Israel, Afghanistan; (6) Soviet Union; (7) France, Germany, Turkey, Belgium, Canada, Netherlands, Switzerland, United Kingdom; and (8) South Africa.

  17. JPRS report, nuclear developments

    SciTech Connect

    1991-01-04

    This report contains articles concerning the nuclear developments of the following countries: (1) China; (2) Japan, North Korea, South Korea; (3) Bulgaria, Czechoslovakia, Rumania; (4) Argentina, Brazil, Peru; (5) India, Iraq, Syria, Israel, Egypt, Mauritania, Pakistan; (6) Soviet Union; (7) France, Germany, Austria, Canada, Italy, Spain; and (8) South Africa.

  18. Preserving Nuclear Grade Knowledge

    SciTech Connect

    Lange, Bob

    2008-02-05

    When people think of the government they think of the President, or Congress, or the Internal Revenue Service (IRS), but there are thousands of people in government-related jobs doing things most don’t really notice everyday. You can find them everywhere, from the space science folks at NASA, to the Federal Bureau of Investigations (FBI) watching out for the bad guys. There are Rangers, and Social Workers, Nurses and Agricultural Managers. They are people working to keep the many facets of the USA rolling. One very diverse bunch is The Department of Energy (DOE) , a group who is expanding the ways we make and save energy to power our cars, homes, and businesses. Tucked away under the DOE is the National Nuclear Security Administration, the NNSA is an agency that maintains the safety, security, and reliability of the U.S. nuclear weapons stockpile. It works to reduce global danger from weapons of mass destruction. It provides the U.S. Navy with safe nuclear propulsion, and it responds to nuclear and radiological emergencies in the United States and abroad, and it supports efforts in science and technology*. (* DOE/NNSA/KCP website info)

  19. Nuclear Radiation Damages Minds!

    ERIC Educational Resources Information Center

    Blai, Boris, Jr.

    Professors Ernest Sternglass (University of Pittsburgh) and Steven Bell (Berry College) have assembled cogent, conclusive evidence indicating that nuclear radiation is associated with impaired cognition. They suggest that Scholastic Aptitude Scores (SATs), which have declined steadily for 19 years, will begin to rise. Their prediction is based on…

  20. Nuclear spin circular dichroism

    SciTech Connect

    Vaara, Juha; Rizzo, Antonio; Kauczor, Joanna; Norman, Patrick; Coriani, Sonia

    2014-04-07

    Recent years have witnessed a growing interest in magneto-optic spectroscopy techniques that use nuclear magnetization as the source of the magnetic field. Here we present a formulation of magnetic circular dichroism (CD) due to magnetically polarized nuclei, nuclear spin-induced CD (NSCD), in molecules. The NSCD ellipticity and nuclear spin-induced optical rotation (NSOR) angle correspond to the real and imaginary parts, respectively, of (complex) quadratic response functions involving the dynamic second-order interaction of the electron system with the linearly polarized light beam, as well as the static magnetic hyperfine interaction. Using the complex polarization propagator framework, NSCD and NSOR signals are obtained at frequencies in the vicinity of optical excitations. Hartree-Fock and density-functional theory calculations on relatively small model systems, ethene, benzene, and 1,4-benzoquinone, demonstrate the feasibility of the method for obtaining relatively strong nuclear spin-induced ellipticity and optical rotation signals. Comparison of the proton and carbon-13 signals of ethanol reveals that these resonant phenomena facilitate chemical resolution between non-equivalent nuclei in magneto-optic spectra.

  1. Nuclear Power in Space.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC. Nuclear Energy Office.

    Research has shown that nuclear radioisotope power generators can supply compact, reliable, and efficient sources of energy for a broad range of space missions. These missions range from televising views of planetary surfaces to communicating scientific data to Earth. This publication presents many applications of the advancing technology and…

  2. Nuclear light bulb

    NASA Technical Reports Server (NTRS)

    Latham, Tom

    1991-01-01

    The nuclear light bulb engine is a closed cycle concept. The nuclear light bulb concept provides containment by keeping the nuclear fuel fluid mechanically suspended in a cylindrical geometry. Thermal heat passes through an internally cooled, fused-silica, transparent wall and heats hydrogen propellant. The seeded hydrogen propellant absorbs radiant energy and is expanded through a nozzle. Internal moderation was used in the configuration which resulted in a reduced critical density requirement. This result was supported by criticality experiments. A reference engine was designed that had seven cells and was sized to fit in what was then predicted to be the shuttle bay mass and volume limitations. There were studies done of nozzle throat cooling schemes to remove the radiant heat. Elements of the nuclear light bulb program included closed loop critical assembly tests done at Los Alamos with UF6 confined by argon buffer gas. It was shown that the fuel region could be seeded with constituents that would block UV radiation from the uranium plasma. A combination of calculations and experiments showed that internal moderation produced a critical mass reduction. Other aspects of the research are presented.

  3. NUCLEAR FUEL COMPOSITION

    DOEpatents

    Spedding, F.H.; Wilhelm, H.A.

    1960-05-31

    A novel reactor composition for use in a self-sustaining fast nuclear reactor is described. More particularly, a fuel alloy comprising thorium and uranium-235 is de scribed, the uranium-235 existing in approximately the same amount that it is found in natural uranium, i.e., 1.4%.

  4. Detecting Illicit Nuclear Materials

    SciTech Connect

    Kouzes, Richard T.

    2005-09-01

    The threat that weapons of mass destruction might enter the United States has led to a number of efforts for the detection and interdiction of nuclear, radiological, chemical, and biological weapons at our borders. There have been multiple deployments of instrumentation to detect radiation signatures to interdict radiological material, including weapons and weapons material worldwide.

  5. Nuclear Power in Japan.

    ERIC Educational Resources Information Center

    Powell, John W.

    1983-01-01

    Energy consumption in Japan has grown at a faster rate than in any other major industrial country. To maintain continued prosperity, the government has embarked on a crash program for nuclear power. Current progress and issues/reactions to the plan are discussed. (JN)

  6. Nuclear Systems Kilopower Overview

    NASA Technical Reports Server (NTRS)

    Palac, Don; Gibson, Marc; Mason, Lee; Houts, Michael; McClure, Patrick; Robinson, Ross

    2016-01-01

    The Nuclear Systems Kilopower Project was initiated by NASAs Space Technology Mission Directorate Game Changing Development Program in fiscal year 2015 to demonstrate subsystem-level technology readiness of small space fission power in a relevant environment (Technology Readiness Level 5) for space science and human exploration power needs. The Nuclear Systems Kilopower Project consists of two elements. The primary element is the Kilopower Prototype Test, also called the Kilopower Reactor Using Stirling Technology(KRUSTY) Test. This element consists of the development and testing of a fission ground technology demonstrator of a 1 kWe fission power system. A 1 kWe system matches requirements for some robotic precursor exploration systems and future potential deep space science missions, and also allows a nuclear ground technology demonstration in existing nuclear test facilities at low cost. The second element, the Mars Kilopower Scalability Study, consists of the analysis and design of a scaled-up version of the 1 kWe reference concept to 10 kWe for Mars surface power projected requirements, and validation of the applicability of the KRUSTY experiment to key technology challenges for a 10 kWe system. If successful, these two elements will lead to initiation of planning for a technology demonstration of a 10 kWe fission power capability for Mars surface outpost power.

  7. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Larsen, Michael; Griffith, Robert; Bulatowicz, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This presentation will describe the operational principles, design basics, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  8. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Griffith, Robert; Larsen, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This poster will describe the history, operational principles, design, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  9. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Larsen, Michael; Mirijanian, James

    2012-06-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation is concluding the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This poster will describe the history, operational principles, and design basics of the NMRG including an overview of the NSD designs developed and demonstrated in the DARPA gyro development program. General performance results from phases 3 and 4 will also be presented.

  10. Nuclear Medical Technology Training.

    ERIC Educational Resources Information Center

    Simmons, Guy H., Ed.

    This 1-day colloquium, attended by 23 participants representing societies, government agencies, colleges and universities, and other training programs, was conducted for the purpose of reporting on and discussing the curriculums developed at the University of Cincinnati for training nuclear medical technologists. Pilot programs at both the…

  11. NUCLEAR POWER PLANT

    DOEpatents

    Carter, J.C.; Armstrong, R.H.; Janicke, M.J.

    1963-05-14

    A nuclear power plant for use in an airless environment or other environment in which cooling is difficult is described. The power plant includes a boiling mercury reactor, a mercury--vapor turbine in direct cycle therewith, and a radiator for condensing mercury vapor. (AEC)

  12. Targeting Nuclear Envelope Repair.

    PubMed

    2016-06-01

    Migrating cancer cells undergo repeated rupture of the protective nuclear envelope as they squeeze through small spaces in the surrounding tissue, compromising genomic integrity. Inhibiting both general DNA repair and the mechanism that seals these tears may enhance cell death and curb metastasis. PMID:27130435

  13. Topics in nuclear power

    NASA Astrophysics Data System (ADS)

    Budnitz, Robert J.

    2015-03-01

    The 101 nuclear plants operating in the US today are far safer than they were 20-30 years ago. For example, there's been about a 100-fold reduction in the occurrence of "significant events" since the late 1970s. Although the youngest of currently operating US plants was designed in the 1970s, all have been significantly modified over the years. Key contributors to the safety gains are a vigilant culture, much improved equipment reliability, greatly improved training of operators and maintenance workers, worldwide sharing of experience, and the effective use of probabilistic risk assessment. Several manufacturers have submitted high quality new designs for large reactors to the U.S. Nuclear Regulatory Commission (NRC) for design approval, and several companies are vigorously working on designs for smaller, modular reactors. Although the Fukushima reactor accident in March 2011 in Japan has been an almost unmitigated disaster for the local population due to their being displaced from their homes and workplaces and also due to the land contamination, its "lessons learned" have been important for the broader nuclear industry, and will surely result in safer nuclear plants worldwide - indeed, have already done so, with more safety improvements to come.

  14. Politics of nuclear waste

    SciTech Connect

    Colglazier, E.W. Jr.

    1982-01-01

    In November of 1979, the Program in Science, Technology and Humanism and the Energy Committee of the Aspen Institute organized a conference on resolving the social, political, and institutional conflicts over the permanent siting of radioactive wastes. This book was written as a result of this conference. The chapters provide a comprehensive and up-to-date overview of the governance issues connected with radioactive waste management as well as a sampling of the diverse views of the interested parties. Chapter 1 looks in depth of radioactive waste management in the United States, with special emphasis on the events of the Carter Administration as well as on the issues with which the Reagen administration must deal. Chapter 2 compares waste management policies and programs among the industralized countries. Chapter 3 examines the factional controversies in the last administration and Congress over nuclear waste issues. Chapter 4 examines the complex legal questions involved in the federal-state conflicts over nuclear waste management. Chapter 5 examines the concept of consultation and concurrence from the perspectives of a host state that is a candidate for a repository and an interested state that has special concerns regarding the demonstration of nuclear waste disposal technology. Chapter 6 examines US and European perspectives concerning public participation in nuclear waste management. Chapter 7 discusses propaganda in the issues. The epilogue attempts to assess the prospects for consensus in the United States on national policies for radioactive waste management. All of the chapter in this book should be interpreted as personal assessments. (DP)

  15. Nuclear Fuel Reprocessing

    SciTech Connect

    Harold F. McFarlane; Terry Todd

    2013-11-01

    Reprocessing is essential to closing nuclear fuel cycle. Natural uranium contains only 0.7 percent 235U, the fissile (see glossary for technical terms) isotope that produces most of the fission energy in a nuclear power plant. Prior to being used in commercial nuclear fuel, uranium is typically enriched to 3–5% in 235U. If the enrichment process discards depleted uranium at 0.2 percent 235U, it takes more than seven tonnes of uranium feed to produce one tonne of 4%-enriched uranium. Nuclear fuel discharged at the end of its economic lifetime contains less one percent 235U, but still more than the natural ore. Less than one percent of the uranium that enters the fuel cycle is actually used in a single pass through the reactor. The other naturally occurring isotope, 238U, directly contributes in a minor way to power generation. However, its main role is to transmute into plutoniumby neutron capture and subsequent radioactive decay of unstable uraniumand neptuniumisotopes. 239Pu and 241Pu are fissile isotopes that produce more than 40% of the fission energy in commercially deployed reactors. It is recovery of the plutonium (and to a lesser extent the uranium) for use in recycled nuclear fuel that has been the primary focus of commercial reprocessing. Uraniumtargets irradiated in special purpose reactors are also reprocessed to obtain the fission product 99Mo, the parent isotope of technetium, which is widely used inmedical procedures. Among the fission products, recovery of such expensive metals as platinum and rhodium is technically achievable, but not economically viable in current market and regulatory conditions. During the past 60 years, many different techniques for reprocessing used nuclear fuel have been proposed and tested in the laboratory. However, commercial reprocessing has been implemented along a single line of aqueous solvent extraction technology called plutonium uranium reduction extraction process (PUREX). Similarly, hundreds of types of reactor

  16. Frontiers in nuclear medicine symposium: Nuclear medicine & molecular biology

    SciTech Connect

    1995-04-01

    This document contains the abstracts from the American College of Nuclear Physicians 1993 Fall Meeting entitled, `Frontiers in Nuclear Medicine Symposium: Nuclear Medicine and Molecular Biology`. This meeting was sponsored by the US DOE, Office of Health and Environmental Research, Office of Energy Research. The program chairman was Richard C. Reba, M.D.

  17. United Campuses to Prevent Nuclear War: Nuclear War Course Summaries.

    ERIC Educational Resources Information Center

    Journal of College Science Teaching, 1983

    1983-01-01

    Briefly describes 46 courses on nuclear war available from United Campuses to Prevent Nuclear War (UCAM). These courses are currently being or have been taught at colleges/universities, addressing effects of nuclear war, arms race history, new weapons, and past arms control efforts. Syllabi (with assignments/reading lists) are available from UCAM.…

  18. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    Biberian, Jean-Paul

    2006-02-01

    1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research

  19. Nuclear material detection techniques

    NASA Astrophysics Data System (ADS)

    Christian, James F.; Sia, Radia; Dokhale, Purushottam; Shestakova, Irina; Nagarkar, Vivek; Shah, Kanai; Johnson, Erik B.; Stapels, Christopher J.; Ryan, James M.; Macri, John; Bravar, Ulisse; Leung, Ka-Ngo; Squillante, Michael R.

    2008-04-01

    Illicit nuclear materials represent a threat for the safety of the American citizens, and the detection and interdiction of a nuclear weapon is a national problem that has not been yet solved. Alleviating this threat represents an enormous challenge to current detection methods that have to be substantially improved to identify and discriminate threatening from benign incidents. Rugged, low-power and less-expensive radiation detectors and imagers are needed for large-scale wireless deployment. Detecting the gamma rays emitted by nuclear and fissionable materials, particularly special nuclear materials (SNM), is the most convenient way to identify and locate them. While there are detectors that have the necessary sensitivity, none are suitable to meet the present need, primarily because of the high occurrence of false alarms. The exploitation of neutron signatures represents a promising solution to detecting illicit nuclear materials. This work presents the development of several detector configurations such as a mobile active interrogation system based on a compact RF-Plasma neutron generator developed at LBNL and a fast neutron telescope that uses plastic scintillating-fibers developed at the University of New Hampshire. A human-portable improved Solid-State Neutron Detector (SSND) intended to replace pressurized 3He-tubes will be also presented. The SSND uses an ultra-compact CMOS-SSPM (Solid-State Photomultiplier) detector, developed at Radiation Monitoring devices Inc., coupled to a neutron sensitive scintillator. The detector is very fast and can provide time and spectroscopy information over a wide energy range including fast neutrons.

  20. Nuclear thermal propulsion program overview

    NASA Technical Reports Server (NTRS)

    Bennett, Gary L.

    1991-01-01

    Nuclear thermal propulsion program is described. The following subject areas are covered: lunar and Mars missions; national space policy; international cooperation in space exploration; propulsion technology; nuclear rocket program; and budgeting.

  1. Nuclear Proliferation and Grand Challenges

    ScienceCinema

    McCarthy, Kathy

    2016-07-12

    Nuclear engineer Dr. Kathy McCarthy leads systems analysis. She talks about proliferation and the grand challenges of nuclear R&D. For more information about INL energy research, visit http://www.facebook.com/idahonationallaboratory.

  2. The Nuclear Debate in Film

    ERIC Educational Resources Information Center

    Dowling, John

    1977-01-01

    Provides a nuclear film bibliography grouped into the areas of: building and using the bomb; living with the bomb; and living with nuclear power. These films are for mature high school students and older. (MLH)

  3. A Career in Nuclear Energy

    ScienceCinema

    Lambregts, Marsha

    2016-07-12

    Nuclear chemist Dr. Marsha Lambregts talks about the Center for Advanced Energy Studies and the benefits of a nuclear energy career. For more information about careers at INL, visit http://www.facebook.com/idahonationallaboratory.

  4. Adventures in scientific nuclear diplomacy

    SciTech Connect

    Hecker, Siegfried S.

    2014-05-09

    A former director of Los Alamos National Laboratory offers a first-person perspective on the important contributions scientists can make toward improving the safety and security of nuclear materials and reducing the global nuclear dangers in an evolving world.

  5. A Career in Nuclear Energy

    SciTech Connect

    Lambregts, Marsha

    2009-01-01

    Nuclear chemist Dr. Marsha Lambregts talks about the Center for Advanced Energy Studies and the benefits of a nuclear energy career. For more information about careers at INL, visit http://www.facebook.com/idahonationallaboratory.

  6. Nuclear Proliferation and Grand Challenges

    SciTech Connect

    McCarthy, Kathy

    2009-01-01

    Nuclear engineer Dr. Kathy McCarthy leads systems analysis. She talks about proliferation and the grand challenges of nuclear R&D. For more information about INL energy research, visit http://www.facebook.com/idahonationallaboratory.

  7. Psychoanalysis and the nuclear threat

    SciTech Connect

    Levine, H.B.; Jacobs, D.; Rubin, L.J.

    1988-01-01

    {ital Psychoanalysis and the Nuclear Threat} provides coverage of the dynamic and clinical considerations that follow from life in the nuclear age. Of special clinical interest are chapters dealing with the developmental consequences of the nuclear threat in childhood, adolescence, and adulthood, and those exploring the technical issues raised by the occurrence in analytic and psychotherapeutic hours of material related to the nuclear threat. Additional chapters bring a psychoanalytic perspective to bear on such issues as the need to have enemies, silence as the real crime, love, work, and survival in the nuclear age, the relationship of the nuclear threat to issues of mourning and melancholia, apocalyptic fantasies, the paranoid process, considerations of the possible impact of gender on the nuclear threat, and the application of psychoanalytic thinking to nuclear arms strategy. Finally, the volume includes the first case report in the English language---albeit a brief psychotherapy---involving the treatment of a Hiroshima survivor.

  8. Nuclear Radiation and the Thyroid

    MedlinePlus

    ... most radiation-sensitive parts of the body. Most nuclear accidents release radioactive iodine into the atmosphere which can ... works? After the 1986 Chornobyl (formerly called “Chernobyl”) nuclear accident, shifting winds blew a radioactive cloud over Europe. ...

  9. Adventures in scientific nuclear diplomacy

    NASA Astrophysics Data System (ADS)

    Hecker, Siegfried S.

    2014-05-01

    A former director of Los Alamos National Laboratory offers a first-person perspective on the important contributions scientists can make toward improving the safety and security of nuclear materials and reducing the global nuclear dangers in an evolving world.

  10. Nuclear Propulsion in Space (1968)

    SciTech Connect

    2012-06-23

    Project NERVA was an acronym for Nuclear Engine for Rocket Vehicle Application, a joint program of the U.S. Atomic Energy Commission and NASA managed by the Space Nuclear Propulsion Office (SNPO) at the Nuclear Rocket Development Station in Jackass Flats, Nevada U.S.A. Between 1959 and 1972, the Space Nuclear Propulsion Office oversaw 23 reactor tests, both the program and the office ended at the end of 1972.

  11. Nuclear weapon detection categorization analysis

    SciTech Connect

    1997-12-01

    This statement of work is for the Proof of Concept for nuclear weapon categories utility in Arms control. The focus of the project will be to collect, analyze and correlate Intrinsic Radiation (INRAD) calculation results for the purpose of defining measurable signatures that differentiate categories of nuclear weapons. The project will support START III negotiations by identifying categories of nuclear weapons. The categories could be used to clarify sub-limits on the total number of nuclear weapons.

  12. Direct nuclear-powered lasers

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1983-01-01

    The development of direct nuclear pumped lasers is reviewed. Theoretical and experimental investigations of various methods of converting the energy of nuclear fission fragments to laser power are summarized. The development of direct nuclear pumped lasers was achieved. The basic processes involved in the production of a plasma by nuclear radiation were studied. Significant progress was accomplished in this area and a large amount of basic data on plasma formation and atomic and molecular processes leading to population inversions is available.

  13. Nuclear Propulsion in Space (1968)

    ScienceCinema

    None

    2016-07-12

    Project NERVA was an acronym for Nuclear Engine for Rocket Vehicle Application, a joint program of the U.S. Atomic Energy Commission and NASA managed by the Space Nuclear Propulsion Office (SNPO) at the Nuclear Rocket Development Station in Jackass Flats, Nevada U.S.A. Between 1959 and 1972, the Space Nuclear Propulsion Office oversaw 23 reactor tests, both the program and the office ended at the end of 1972.

  14. Nuclear eclectic power.

    PubMed

    Rose, D J

    1974-04-19

    The uranium and thorium resources, the technology, and the social impacts all seem to presage an even sharper increase in nuclear power for electric generation than had hitherto been predicted. There are more future consequences. The "hydrogen economy." Nuclear power plants operate best at constant power and full load. Thus, a largely nuclear electric economy has the problem of utilizing substantial off-peak capacity; the additional energy generation can typically be half the normal daily demand. Thus, the option of generating hydrogen as a nonpolluting fuel receives two boosts: excess nuclear capacity to produce it, plus much higher future costs for oil and natural gas. However, the so-called "hydrogen economy" must await the excess capacity, which will not occur until the end of the century. Nonelectric uses. By analyses similar to those performed here, raw nuclear heat can be shown to be cheaper than heat from many other fuel sources, especially nonpolluting ones. This will be particularly true as domestic natural gas supplies become more scarce. Nuclear heat becomes attractive for industrial purposes, and even for urban district heating, provided (i) the temperature is high enough (this is no problem for district heating, but could be for industry; the HTGR's and breeders, with 600 degrees C or more available, have the advantage); (ii) there is a market for large quantities (a heat rate of 3800 Mw thermal, the reactor size permitted today, will heat Boston, with some to spare); and (iii) the social costs become more definitely resolved in favor of nuclear power. Capital requirements. Nuclear-electric installations are very capital-intensive. One trillion dollars for the plants, backup industry, and so forth is only 2 percent of the total gross national product (GNP) between 1974 and 2000, at a growth rate of 4 percent per year. But capital accumulation tends to run at about 10 percent of the GNP, so the nuclear requirements make a sizable perturbation. Also

  15. Nuclear eclectic power.

    PubMed

    Rose, D J

    1974-04-19

    The uranium and thorium resources, the technology, and the social impacts all seem to presage an even sharper increase in nuclear power for electric generation than had hitherto been predicted. There are more future consequences. The "hydrogen economy." Nuclear power plants operate best at constant power and full load. Thus, a largely nuclear electric economy has the problem of utilizing substantial off-peak capacity; the additional energy generation can typically be half the normal daily demand. Thus, the option of generating hydrogen as a nonpolluting fuel receives two boosts: excess nuclear capacity to produce it, plus much higher future costs for oil and natural gas. However, the so-called "hydrogen economy" must await the excess capacity, which will not occur until the end of the century. Nonelectric uses. By analyses similar to those performed here, raw nuclear heat can be shown to be cheaper than heat from many other fuel sources, especially nonpolluting ones. This will be particularly true as domestic natural gas supplies become more scarce. Nuclear heat becomes attractive for industrial purposes, and even for urban district heating, provided (i) the temperature is high enough (this is no problem for district heating, but could be for industry; the HTGR's and breeders, with 600 degrees C or more available, have the advantage); (ii) there is a market for large quantities (a heat rate of 3800 Mw thermal, the reactor size permitted today, will heat Boston, with some to spare); and (iii) the social costs become more definitely resolved in favor of nuclear power. Capital requirements. Nuclear-electric installations are very capital-intensive. One trillion dollars for the plants, backup industry, and so forth is only 2 percent of the total gross national product (GNP) between 1974 and 2000, at a growth rate of 4 percent per year. But capital accumulation tends to run at about 10 percent of the GNP, so the nuclear requirements make a sizable perturbation. Also

  16. Nuclear Wallet Cards from the National Nuclear Data Center (NNDC)

    DOE Data Explorer

    Tuli, Jagdish K.

    Nuclear Wallet Cards present properties for ground and isomeric states of all known nuclides. Properties given are: spin and parity assignments, nuclear mass excesses, half-life, isotopic abundances, and decay modes. Appendices contain properties of elements, fundamental constants and other useful information. Nuclear Wallet Cards booklet is published by the National Nuclear Data Center and its electronic (current) version is periodically updated. The Nuclear Wallet Cards by Dr. Jagdish K. Tuli, presently in its 8th edition, is distributed in print as well as in PDA-adaptable Palm Pilot format; the data table as an ASCII file is available upon request. [Taken from http://www.nndc.bnl.gov/wallet/

  17. Game Imaging Meets Nuclear Reality

    SciTech Connect

    Michel, Kelly; Watkins, Adam

    2011-03-21

    At Los Alamos National Laboratory, a team of artists and animators, nuclear engineers and computer scientists is teaming to provide 3-D models of nuclear facilities to train IAEA safeguards inspectors and others who need fast familiarity with specific nuclear sites.

  18. Report Card on Nuclear Power

    ERIC Educational Resources Information Center

    Novick, Sheldon

    1974-01-01

    Problems facing the nuclear power industry include skyrocketing construction costs, technical failures, fuel scarcity, power plant safety, and the disposal of nuclear wastes. Possible solutions include: reductions in nuclear power plant construction, a complete moratorium on new plant construction, the construction of fast breeder reactors and the…

  19. Game Imaging Meets Nuclear Reality

    ScienceCinema

    Michel, Kelly; Watkins, Adam

    2016-07-12

    At Los Alamos National Laboratory, a team of artists and animators, nuclear engineers and computer scientists is teaming to provide 3-D models of nuclear facilities to train IAEA safeguards inspectors and others who need fast familiarity with specific nuclear sites.

  20. Nuclear Technology: Making Informed Decisions.

    ERIC Educational Resources Information Center

    Altshuler, Kenneth

    1989-01-01

    Discusses a unit on nuclear technology which is taught in a physics class. Explains the unit design, implementation process, demonstrations used, and topics of discussion that include light and optics, naturally and artificially produced sources of radioactivity, nuclear equations, isotopes and half-lives, and power-generating nuclear reactors.…

  1. Job Prospects for Nuclear Engineers.

    ERIC Educational Resources Information Center

    Basta, Nicholas

    1987-01-01

    Discusses trends in job opportunities for nuclear engineers. Lists some of the factors influencing increases and decreases in the demand for nuclear engineers. Describes the effects on career opportunities from recent nuclear accidents, military research and development, and projected increases of demand for electricity. (TW)

  2. Overview paper on nuclear power

    SciTech Connect

    Spiewak, I.; Cope, D.F.

    1980-09-01

    This paper was prepared as an input to ORNL's Strategic Planning Activity, ORNL National Energy Perspective (ONEP). It is intended to provide historical background on nuclear power, an analysis of the mission of nuclear power, a discussion of the issues, the technology choices, and the suggestion of a strategy for encouraging further growth of nuclear power.

  3. Nuclear magics at explosive magnetization

    NASA Astrophysics Data System (ADS)

    Kondratyev, V. N.

    2016-05-01

    Effects of ultra-strong magnetization in creation of iron group nuclides are considered by employing arguments of nuclear statistical equilibrium. Nuclear magnetic reactivity is demonstrated to enhance the portion of titanium product due to magnetic modification of nuclear structure. The results are corroborated with an excess of 44Ti revealed from the Integral mission data.

  4. Behavior, society, and nuclear war

    SciTech Connect

    Tetlock, P.E.; Husbands, J.L.; Jervis, R.; Stern, P.C.; Tilly, C.

    1989-01-01

    This book contains chapters on the following topics related to nuclear arms and nuclear war: crisis decision making; behavioral aspects of negotiations on mutual security; democracy, public opinion, and nuclear weapons; the case of wars; A review of theories; methodological themes and variations.

  5. Job Prospects for Nuclear Engineers.

    ERIC Educational Resources Information Center

    Basta, Nicholas

    1985-01-01

    As the debate over nuclear safety continues, the job market remains healthy for nuclear engineers. The average salary offered to new nuclear engineers with bachelor's degrees is $27,400. Salary averages and increases compare favorably with other engineering disciplines. Various job sources in the field are noted. (JN)

  6. Nuclear dreams: the malignant alteration of nuclear architecture.

    PubMed

    Nickerson, J A

    1998-08-01

    Cancer is diagnosed by examining the architectural alterations to cells and tissues. Changes in nuclear structure are among the most universal of these and include increases in nuclear size, deformities in nuclear shape, and changes in the internal organization of the nucleus. These may all reflect changes in the nuclear matrix, a non-chromatin nuclear scaffolding determining nuclear form, higher order chromatin folding, and the spatial organization of nucleic acid metabolism. Malignancy-induced changes in this structure may have profound effects on chromatin folding, on the fidelity of genome replication, and on gene expression. Elucidating the mechanisms and the biological consequences of nuclear changes will require the identification of the major structural molecules of the internal nuclear matrix and an understanding of their assembly into structural elements. If biochemical correlates to malignant alterations in nuclear structure can be identified then nuclear matrix proteins and, perhaps nuclear matrix-associated structural RNAs, may be an attractive set of diagnostic markers and therapeutic targets.

  7. Historical civilian nuclear accident based Nuclear Reactor Condition Analyzer

    NASA Astrophysics Data System (ADS)

    McCoy, Kaylyn Marie

    There are significant challenges to successfully monitoring multiple processes within a nuclear reactor facility. The evidence for this observation can be seen in the historical civilian nuclear incidents that have occurred with similar initiating conditions and sequences of events. Because there is a current lack within the nuclear industry, with regards to the monitoring of internal sensors across multiple processes for patterns of failure, this study has developed a program that is directed at accomplishing that charge through an innovation that monitors these systems simultaneously. The inclusion of digital sensor technology within the nuclear industry has appreciably increased computer systems' capabilities to manipulate sensor signals, thus making the satisfaction of these monitoring challenges possible. One such manipulation to signal data has been explored in this study. The Nuclear Reactor Condition Analyzer (NRCA) program that has been developed for this research, with the assistance of the Nuclear Regulatory Commission's Graduate Fellowship, utilizes one-norm distance and kernel weighting equations to normalize all nuclear reactor parameters under the program's analysis. This normalization allows the program to set more consistent parameter value thresholds for a more simplified approach to analyzing the condition of the nuclear reactor under its scrutiny. The product of this research provides a means for the nuclear industry to implement a safety and monitoring program that can oversee the system parameters of a nuclear power reactor facility, like that of a nuclear power plant.

  8. The ``Nuclear Renaissance'' and the Spread of Nuclear Weapons

    NASA Astrophysics Data System (ADS)

    Lyman, Edwin S.

    2007-05-01

    As interest grows around the world in nuclear power as an energy source that could help control greenhouse gas emissions, some have proclaimed the arrival of a ``nuclear renaissance.'' But can the increased risks of more nuclear power be managed? The political crisis surrounding Iran's pursuit of uranium enrichment has exposed weaknesses in the nuclear nonproliferation regime. Also, al Qaeda's declared interest in weapons of mass destruction raises the concern that terrorists could acquire nuclear weapons by stealing materials from poorly secured facilities. Growth of nuclear energy would require the construction of many additional uranium enrichment plants. And the generation of more spent nuclear fuel without a credible waste disposal strategy would increase political support for reprocessing, which separates large quantities of weapon-usable plutonium from spent fuel. There is little evidence that the various institutional arrangements and technical schemes proposed to mitigate the security risks of a major nuclear expansion would be effective. This talk will focus on the measures necessary to allow large-scale global growth of nuclear power without resulting in an unacceptably high risk of nuclear proliferation and nuclear terrorism, and will discuss the feasibility of such measures. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.OSS07.E1.2

  9. Leading twist nuclear shadowing, nuclear generalized parton distributions and nuclear DVCS at small x

    SciTech Connect

    Guzey, Vadim; Goeke, Klaus; Siddikov, Marat

    2009-01-01

    We generalize the leading twist theory of nuclear shadowing and calculate quark and gluon generalized parton distributions (GPDs) of spinless nuclei. We predict very large nuclear shadowing for nuclear GPDs. In the limit of the purely transverse momentum transfer, our nuclear GPDs become impact parameter dependent nuclear parton distributions (PDFs). Nuclear shadowing induces non-trivial correlations between the impact parameter $b$ and the light-cone fraction $x$. We make predictions for the deeply virtual Compton scattering (DVCS) amplitude and the DVCS cross section on $^{208}$Pb at high energies. We calculate the cross section of the Bethe-Heitler (BH) process and address the issue of the extraction of the DVCS signal from the $e A \\to e \\gamma A$ cross section. We find that the $e A \\to e \\gamma A$ differential cross section is dominated by DVCS at the momentum transfer $t$ near the minima of the nuclear form factor. We also find that nuclear shadowing leads

  10. Uranium droplet nuclear reactor core with MHD generator

    NASA Astrophysics Data System (ADS)

    Anghaie, Samim; Kumar, Ratan

    An innovative concept employing liquid uranium droplets as fuel in an ultrahigh-temperature vapor core reactor (UTVR) magnetohydrodynamic (MHD) generator power system for space power generation has been studied. Metallic vapor in superheated form acts as a working fluid for a closed-Rankine-type thermodynamic cycle. Usage of fuel and working fluid in this form assures certain advantages. The major technical issues emerging as a result involve a method for droplet generation, droplet transport in the reactor core, heat generation in the fuel and transport to the metallic vapor, and materials compatibility. A qualitative and quantitative attempt to resolve these issues has indicated the promise and tentative feasibility of the system.

  11. Nuclear shell evolution

    NASA Astrophysics Data System (ADS)

    Bentley, Ian

    2016-03-01

    The appearance and disappearance of nuclear shells and sub-shells has been at the forefront of recent nuclear theory and experimental efforts. This work extends a previously introduced method of structural analysis and applies it to protons in an attempt to provide a more complete understanding of shell structure in nuclei. Experimental observables including the mean square charge radius, as well as other spectroscopic and mass related quantities have been analyzed for shell structure features. A preliminary analysis using Nilsson coefficient fits of experimental quantities, such as odd mass spectra and B(E2) values, along isotopic chains will be discussed. The goal of this work is to provide a means of predicting shell structure far from stability. This work was supported by the National Science Foundation under Grants PHY1419765 and PHY0822648.

  12. The nuclear battery

    NASA Astrophysics Data System (ADS)

    Kozier, K. S.; Rosinger, H. E.

    The evolution and present status of an Atomic Energy of Canada Limited program to develop a small, solid-state, passively cooled reactor power supply known as the Nuclear Battery is reviewed. Key technical features of the Nuclear Battery reactor core include a heat-pipe primary heat transport system, graphite neutron moderator, low-enriched uranium TRISO coated-particle fuel and the use of burnable poisons for long-term reactivity control. An external secondary heat transport system extracts useful heat energy, which may be converted into electricity in an organic Rankine cycle engine or used to produce high-pressure steam. The present reference design is capable of producing about 2400 kW(t) (about 600 kW(e) net) for 15 full-power years. Technical and safety features are described along with recent progress in component hardware development programs and market assessment work.

  13. Nuclear functions of prefoldin

    PubMed Central

    Millán-Zambrano, Gonzalo; Chávez, Sebastián

    2014-01-01

    Prefoldin is a cochaperone, present in all eukaryotes, that cooperates with the chaperonin CCT. It is known mainly for its functional relevance in the cytoplasmic folding of actin and tubulin monomers during cytoskeleton assembly. However, both canonical and prefoldin-like subunits of this heterohexameric complex have also been found in the nucleus, and are functionally connected with nuclear processes in yeast and metazoa. Plant prefoldin has also been detected in the nucleus and physically associated with a gene regulator. In this review, we summarize the information available on the involvement of prefoldin in nuclear phenomena, place special emphasis on gene transcription, and discuss the possibility of a global coordination between gene regulation and cytoplasmic dynamics mediated by prefoldin. PMID:25008233

  14. Cryogenic nuclear gyroscope

    SciTech Connect

    Gallop, J.C.; Potts, S.P.

    1980-09-30

    A cryogenic nuclear gyroscope is described that is comprised of a cylinder of niobium cooled within a helium cryostat so as to be superconducting and to provide a trapped, substantially homogeneous magnetic field, a helium-3 sample contained within a spherical pyrex cell having nuclei possessing a net magnetic moment, coils provided to polarize the sample to provide that net magnetic moment, and a SQUID magnetometer coupled to the sample by a pick-up coil of a transformer and frequency sensitive means coupled to the SQUID to detect changes in the precession of the nuclear moments of the sample caused by rotation of the gyroscope about an axis parallel to the direction of the homogeneous magnetic field. A superconducting lead shield isolates the helium-3 sample from external magnetic fields.

  15. Traceability in nuclear medicine

    NASA Astrophysics Data System (ADS)

    Zimmerman, Brian E.; Judge, Steven

    2007-08-01

    Accurate, reproducible measurement of radioactivity in nuclear medicine applications is vital to ensure the safety and effectiveness of disease diagnosis and treatment using unsealed radioactive sources. The need to maintain a high degree of confidence in those measurements requires that they be carried out so as to be traceable to national and international standards. In addition, measurement traceability for radioactivity in medicine helps ensure international consistency in measurement at all levels of practice (national measurement laboratories, research institutions, isotope producers, radiopharmaceutical manufacturers and clinics). This paper explores the importance of radioactivity measurement in nuclear medicine and demonstrates how traceability can be extended from international standards to the quantity of the drug administered to the patient.

  16. Preventing nuclear war

    SciTech Connect

    Fisher, R.

    1981-03-01

    By focusing on military hardware, we ignore the human side of the nuclear war problem and how we think about nuclear weapons. Three sets of assumptions are examined: our goals, the means of pursuing these goals, and how to allocate responsibility. The quest for power and peace, for example, will not be attained by a war of mutual destruction. The assumption that every problem has a military solution forecloses diplomacy and negotiation, approaches that require understanding and reconciling different interests. With no military solution, a new security system should be one of shared responsibility in which each person will seize opportunities that help to educate the public, lead to wiser decisions, and reduce the risk of war. (DCK)

  17. Topics in Nuclear Power

    NASA Astrophysics Data System (ADS)

    Budnitz, Robert J.

    2011-11-01

    The 104 nuclear plants operating in the US today are far safer than they were 20-30 years ago. For example, there's been about a 100-fold reduction in the occurrence of "significant events" since the late 1970s. Although the youngest of currently operating US plants was designed in the 1970s, all have been significantly modified over the years. Key contributors to the safety gains are a vigilant culture, much improved equipment reliability, greatly improved training of operators and maintenance workers, worldwide sharing of experience, and the effective use of probabilistic risk assessment. Several manufacturers have submitted high quality new designs for large reactors to the U.S. Nuclear Regulatory Commission (NRC) for design approval, and some designers are taking a second look at the economies of smaller, modular reactors.

  18. Rutherford's Nuclear Model

    NASA Astrophysics Data System (ADS)

    Heibron, John

    2011-04-01

    Rutherford's nuclear model originally was a theory of scattering that represented both the incoming alpha particles and their targets as point charges. The assumption that the apha particle, which Rutherford knew to be a doubly ionized helium atom, was a bare nucleus, and the associated assumption that the electronic structure of the atom played no significant role in large-angle scattering, had immediate and profound consequences well beyond the special problem for which Rutherford introduced them. The group around him in Manchester in 1911/12, which included Niels Bohr, Charles Darwin, Georg von Hevesy, and Henry Moseley, worked out some of these consequences. Their elucidation of radioactivity, isotopy, atomic number, and quantization marked an epoch in microphysics. Rutherford's nuclear model was exemplary not only for its fertility and picturability, but also for its radical simplicity. The lecturer will not undertake to answer the baffling question why such simple models work.

  19. Nuclear electric propulsion

    NASA Technical Reports Server (NTRS)

    Keaton, Paul W.; Tubb, David J.

    1986-01-01

    The feasibility is investigated of using nuclear electric propulsion (NEP) for slow freighter ships traveling from a 500 km low Earth orbit (LEO) to the Moon's orbit about the Earth, and on to Mars. NEP is also shown to be feasible for transporting people to Mars on long conjunction-class missions lasting about nine months one way, and on short sprint missions lasting four months one way. Generally, it was not attempted to optimize ion exhaust velocities, but rather suitable parameters to demonstrate NEP feasibility were chosen. Various combinations of missions are compared with chemical and nuclear thermal propulsion (NTR) systems. Typically, NEP and NTR can accomplish the same lifting task with similar mass in LEO. When compared to chemical propulsion, NEP was found to accomplish the same missions with 40% less mass in LEO. These findings are sufficiently encouraging as to merit further studies with optimum systems.

  20. High level nuclear waste

    SciTech Connect

    Crandall, J L

    1980-01-01

    The DOE Division of Waste Products through a lead office at Savannah River is developing a program to immobilize all US high-level nuclear waste for terminal disposal. DOE high-level wastes include those at the Hanford Plant, the Idaho Chemical Processing Plant, and the Savannah River Plant. Commercial high-level wastes, for which DOE is also developing immobilization technology, include those at the Nuclear Fuel Services Plant and any future commercial fuels reprocessing plants. The first immobilization plant is to be the Defense Waste Processing Facility at Savannah River, scheduled for 1983 project submission to Congress and 1989 operation. Waste forms are still being selected for this plant. Borosilicate glass is currently the reference form, but alternate candidates include concretes, calcines, other glasses, ceramics, and matrix forms.

  1. Nuclear overlap functions

    SciTech Connect

    Eskola, K.J.; Vogt, R.; Wang, X.N.

    1995-07-01

    A three parameter Wood-Saxon shape is used to describe the nuclear density distribution, which R{sub A} is the nuclear radius, {approx} is the surface thickness, and {omega} allows for central irregularities. The electron scattering data is used where available for R{sub A}, z, and {omega}. When data is unavailable, the parameters {omega} = O, z = 0.54 fm and R{sub A} = 1.19 A{sup 1/3} - 1.61 A{sup -1/3} fm are used. The central density {rho}{sub 0} is found from the normalization {infinity} d{sup 3}r{rho}{sub A}(r) = A.

  2. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro

    Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation

  3. Nuclear war: preventable or inevitable?

    PubMed

    Smith, Richard

    1984-06-23

    Smith reports at length on the fourth meeting of International Physicians for the Prevention of Nuclear War, held in Helsinki in 1984 and attended by 450 doctors from 53 countries. Among the topics addressed by the delegates were the preventability of nuclear war, the threat of nuclear winter, the expenditure on atomic weapons of funds that could be used for health programs, the effects on children of the threat of nuclear conflict, and the danger of accidental nuclear war. The meeting concluded with a letter sent from the conference to the leaders of the United States and the Soviet Union.

  4. Challenges in nuclear structure theory

    NASA Astrophysics Data System (ADS)

    Nazarewicz, W.

    2016-08-01

    The goal of nuclear structure theory is to build a comprehensive microscopic framework in which properties of nuclei and extended nuclear matter, and nuclear reactions and decays can all be consistently described. Due to novel theoretical concepts, breakthroughs in the experimentation with rare isotopes, increased exchange of ideas across different research areas, and the progress in computer technologies and numerical algorithms, nuclear theorists have been quite successful in solving various bits and pieces of the nuclear many-body puzzle and the prospects are exciting. This article contains a brief, personal perspective on the status of the field.

  5. Advanced Nuclear Fuel Cycle Options

    SciTech Connect

    Roald Wigeland; Temitope Taiwo; Michael Todosow; William Halsey; Jess Gehin

    2010-06-01

    A systematic evaluation has been conducted of the potential for advanced nuclear fuel cycle strategies and options to address the issues ascribed to the use of nuclear power. Issues included nuclear waste management, proliferation risk, safety, security, economics and affordability, and sustainability. The two basic strategies, once-through and recycle, and the range of possibilities within each strategy, are considered for all aspects of the fuel cycle including options for nuclear material irradiation, separations if needed, and disposal. Options range from incremental changes to today’s implementation to revolutionary concepts that would require the development of advanced nuclear technologies.

  6. Materials in Nuclear Waste Disposition

    NASA Astrophysics Data System (ADS)

    Rebak, Raul B.

    2014-03-01

    Commercial nuclear energy has been used for over 6 decades; however, to date, none of the 30+ countries with nuclear power has opened a repository for high-level waste (HLW). All countries with nuclear waste plan to dispose of it in metallic containers located in underground geologically stable repositories. Some countries also have liquid nuclear waste that needs to be reduced and vitrified before disposition. The five articles included in this topic offer a cross section of the importance of alloy selection to handle nuclear waste at the different stages of waste processing and disposal.

  7. Development of Curricula for Nuclear Radiation Protection, Nuclear Instrumentation, and Nuclear Materials Processing Technologies. Final Report.

    ERIC Educational Resources Information Center

    Hull, Daniel M.

    A study was conducted to assist two-year postsecondary educational institutions in providing technical specialty courses for preparing nuclear technicians. As a result of project activities, curricula have been developed for five categories of nuclear technicians and operators: (1) radiation protection technician, (2) nuclear instrumentation and…

  8. Cold nuclear fusion

    SciTech Connect

    Tsyganov, E. N.

    2012-02-15

    Recent accelerator experiments on fusion of various elements have clearly demonstrated that the effective cross-sections of these reactions depend on what material the target particle is placed in. In these experiments, there was a significant increase in the probability of interaction when target nuclei are imbedded in a conducting crystal or are a part of it. These experiments open a new perspective on the problem of so-called cold nuclear fusion.

  9. Nuclear Physics Review

    SciTech Connect

    Walker-Loud, Andre

    2014-11-01

    Anchoring low-energy nuclear physics to the fundamental theory of strong interactions remains an outstanding challenge. I review the current progress and challenges of the endeavor to use lattice QCD to bridge this connection. This is a particularly exciting time for this line of research as demonstrated by the spike in the number of different collaborative efforts focussed on this problem and presented at this conference. I first digress and discuss the 2013 Ken Wilson Award.

  10. Nuclear medicine in oncology

    SciTech Connect

    Murphy, J.

    1996-12-31

    Radioactivity was discovered in the late 1890s, and as early as 1903, Alexander Graham Bell advocated that radioactivity be used to treat tumors. In 1913, the first paper describing therapeutic uses of radium was published; in 1936, {sup 24}Na was administered as a therapy to a leukemia patient. Three years later, uptake of {sup 89}Sr was noted in bone metastases. During the 1940s, there was increasing use of iodine therapy for thyroid diseases, including thyroid cancer. Diagnostic {open_quotes}imaging{close_quotes} with radioisotopes was increasingly employed in the 1930s and 40s using probes and grew in importance and utility with the development of scintillation detectors with photorecording systems. Although coincidence counting to detect positron emissions was developed in 1953, the first medical center cyclotron was not installed until 1961. The 1960s saw the development of {sup 99m}Tc-labeled radiopharmaceuticals, emission reconstruction tomography [giving rise to single photon emission computed tomography (SPECT) and positron emission tomography (PET)], and {sup 64}Ga tumor imaging. Nuclear medicine was recognized as a medical specialty in 1971. Radiolabeled antibodies targeting human tumors in animals was reported in 1973; antibody tumor imaging in humans was reported in 1978. Technology has continued to advance, including the development of SPECT cameras with coincidence detection able to perform FDG/PET imaging. With this overview as as backdrop, this paper focuses on the role of nuclear medicine in oncology from three perspectives: nonspecific tumor imaging agents, specific tumor imaging agents, and radioisotopes for tumor therapy. In summary, while tumor diagnosis and treatment were among the first uses explored for radioactivity, these areas have yet to reach their full potential. Development of new radioisotopes and new radiopharmaceuticals, coupled with improvements in technology, make nuclear oncology an area of growth for nuclear medicine.

  11. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro

    Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation

  12. Post detonation nuclear forensics

    SciTech Connect

    Davis, Jay

    2014-05-09

    The problem of working backwards from the debris of a nuclear explosion to attempt to attribute the event to a particular actor is singularly difficult technically. However, moving from physical information of any certainty through the political steps that would lead to national action presents daunting policy questions as well. This monograph will outline the operational and physical components of this problem and suggest the difficulty of the policy questions that remain.

  13. Nuclear Regulatory Commission issuances

    SciTech Connect

    1996-04-01

    This report includes the issuances received during the April 1996 reporting period from the Commission, the Atomic Safety and Licensing Boards, the Administrative Law Judges, the Directors` Decisions, and the Decisions on Petitions for Rulemaking. Included are issuances pertaining to: (1) Yankee Nuclear Power Station, (2) Georgia Tech Research Reactor, (3) River Bend Station, (4) Millstone Unit 1, (5) Thermo-Lag fire barrier material, and (6) Louisiana Energy Services.

  14. Nuclear core positioning system

    DOEpatents

    Garkisch, Hans D.; Yant, Howard W.; Patterson, John F.

    1979-01-01

    A structural support system for the core of a nuclear reactor which achieves relatively restricted clearances at operating conditions and yet allows sufficient clearance between fuel assemblies at refueling temperatures. Axially displaced spacer pads having variable between pad spacing and a temperature compensated radial restraint system are utilized to maintain clearances between the fuel elements. The core support plates are constructed of metals specially chosen such that differential thermal expansion produces positive restraint at operating temperatures.

  15. Australia and nuclear war

    SciTech Connect

    Denborough, M.A.

    1985-01-01

    This volume compiles the papers presented in the conference held in May 1983 under the auspices of the Center for Continuing Education at the Australian National University. It also includes some previously unpublished scientific research. The papers range from analyses of the atmospheric and medical consequences of nuclear war to summaries of the efforts of people in all walks of life to prevent a global catastrophe.

  16. Nuclear Medicine Annual, 1986

    SciTech Connect

    Freeman, L.M.; Weissmann, H.S.

    1986-01-01

    Nuclear Medicine Annual, l986 features state-of-the-art reports on the technical aspects and clinical applications of single-photon emission computed tomography, as well as on monoclonal antibodies for radioimmunoimaging and on receptorbinding radiopharmaceuticals. Also included is a review of magnetic resonance imaging of congenital cardiac abnormalities. Other contributions cover bone mineral measurements; skeletal scintigraphy of the hands and wrists; and radionuclide blood-pool imaging in the diagnosis of deep-vein thrombosis of the leg.

  17. Nuclear reactor decontamination

    SciTech Connect

    Torok, J.

    1981-09-01

    Heat transfer and associated surfaces in nuclear reactors are decontaminated by treating the surface with ozone to oxidize acid -insoluble metal oxides to a more soluble state, removing oxidized solubilized metal oxides, and removing other surface oxides using low concentrations of decontaminating reagents. Ozone treatment has been found very effective with alloys having surface metal oxides rendered more easily dissolved by ozone oxidation especially with chromium or chromium-nickel containing alloys.

  18. Nuclear spectroscopic studies

    SciTech Connect

    Bingham, C.R.; Guidry, M.W.; Riedinger, L.L.; Sorensen, S.P.

    1993-02-08

    The Nuclear Physics group at the University of Tennessee, Knoxville is involved in several aspects of heavy-ion physics including both nuclear structure and reaction mechanisms. While our main emphasis is on experimental problems involving heavy-ion accelerators, we have maintained a strong collaboration with several theorists in order to best pursue the physics of our measurements. During the last year we have led several experiments at the Holifield Heavy Ion Research Facility and participated in others at Argonne National Laboratory. Also, we continue to be very active in the collaboration to study ultra-relativistic heavy ion physics utilizing the SPS accelerator at CERN in Geneva, Switzerland and in a RHIC detector R D project. Our experimental work is in four broad areas: (1) the structure of nuclei at high angular momentum, (2) heavy-ion induced transfer reactions, (3) the structure of nuclei far from stability, and (4) ultra-relativistic heavy-ion physics. The results of studies in these particular areas will be described in this document in sections IIA, IIB, IIC, and IID, respectively. Areas (1), (3), and (4) concentrate on the structure of nuclear matter in extreme conditions of rotational motion, imbalance of neutrons and protons, or very high temperature and density. Area (2) pursues the transfer of nucleons to states with high angular momentum, both to learn about their structure and to understand the transfer of particles, energy, and angular momentum in collisions between heavy ions. An important component of our program is the strong emphasis on the theoretical aspects of nuclear structure and reactions.

  19. Nuclear hybrid energy infrastructure

    SciTech Connect

    Agarwal, Vivek; Tawfik, Magdy S.

    2015-02-01

    The nuclear hybrid energy concept is becoming a reality for the US energy infrastructure where combinations of the various potential energy sources (nuclear, wind, solar, biomass, and so on) are integrated in a hybrid energy system. This paper focuses on challenges facing a hybrid system with a Small Modular Reactor at its core. The core of the paper will discuss efforts required to develop supervisory control center that collects data, supports decision-making, and serves as an information hub for supervisory control center. Such a center will also be a model for integrating future technologies and controls. In addition, advanced operations research, thermal cycle analysis, energy conversion analysis, control engineering, and human factors engineering will be part of the supervisory control center. Nuclear hybrid energy infrastructure would allow operators to optimize the cost of energy production by providing appropriate means of integrating different energy sources. The data needs to be stored, processed, analyzed, trended, and projected at right time to right operator to integrate different energy sources.

  20. Progress in Nuclear Detection

    NASA Astrophysics Data System (ADS)

    Vojtech, Richard

    2010-02-01

    The Transformational and Applied Research Directorate (TAR) was established within the Department of Homeland Security's Domestic Nuclear Detection Office (DNDO) to conduct, support, coordinate, and encourage near- and long-term Research and Development (R&D) programs for break-through technologies designed to dramatically improve capabilities to detect and report illicit trafficking of nuclear and radiological materials. These programs cover a wide range of technologies and high-level technical challenges associated with the DNDO mission and the Global Nuclear Detection Architecture (GNDA). They encompass a range of technology levels, ranging from feasibility and proof of concept studies to technology demonstrations of systems. Even though the focus is on high level challenges, the direction of some topic areas can change from year to year. This presentation will provide an overview of the TAR mission and discuss the current status of transformational R&D efforts in three major program areas: Advanced Technology Demonstrations (ATD), Exploratory Research (ER) and Academic Research Initiative (ARI). )