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Udagawa, Yutaka; Sugiyama, Tomoyuki; Amaya, Masaki
Japan Atomic Energy Agency, Tokai, Ibaraki (Japan)2014
Japan Atomic Energy Agency, Tokai, Ibaraki (Japan)2014
AbstractAbstract
[en] The temperature evolution of fuel cladding during a reactivity-initiated accident (RIA) involves rapid changes in the mechanical properties of the cladding tube and is believed to play the primary role in fuel behaviors such as deformation and failure. Cladding-temperature behavior accompanied by boiling of coolant water, which is the case of an RIA in light-water reactors, is influenced by cooling conditions such as subcooling, pressure, and flow velocity. In order to study the effects of cooling conditions on the boiling heat transfer from the fuel rod surface to the coolant water, RIA-simulating experiments with fresh fuels had been conducted in the nuclear safety research reactor (NSRR) under cooling conditions with subcoolings of ∼10 to 80 K, flow velocities of 0 to ∼3 m/s, pressures of 0.1 to ∼16 MPa. In addition, pre-irradiated fuels had been subjected to the NSRR experiments under cooling conditions with subcoolings of ∼80 K, stagnant water, and atmospheric pressure. Out of the NSRR experiments, this report presents the fuel specifications, the test conditions, and the transient records during the pulse operations for the cases that the cladding temperature had been successfully measured. Characteristic parameters such as cladding peak temperatures were extracted from the transient records for summarizing the effects of cooling conditions and pre-irradiation on the heat transfer from the cladding surface. A CD-ROM's attached as an appendix. (J.P.N.)
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Feb 2014; 1118 p; Also available from JAEA; URL: http://dx.doi.org/10.11484/JAEA-Data-Code-2013-021; 13 refs., 60 figs.
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Report
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ACCIDENTS, BOILING, COOLING, ENERGY TRANSFER, ENRICHED URANIUM REACTORS, FUEL ELEMENTS, HEAT FLUX, HOMOGENEOUS REACTORS, HYDRIDE MODERATED REACTORS, MIXED SPECTRUM REACTORS, PHASE TRANSFORMATIONS, PHYSICAL PROPERTIES, PULSED REACTORS, REACTOR COMPONENTS, REACTORS, RESEARCH AND TEST REACTORS, RESEARCH REACTORS, SOLID HOMOGENEOUS REACTORS, THERMODYNAMIC PROPERTIES, WATER COOLED REACTORS, WATER MODERATED REACTORS
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Maisonobe, Romain
Universite de Grenoble, 38400 Saint-Martin-d'Heres (France)2014
Universite de Grenoble, 38400 Saint-Martin-d'Heres (France)2014
AbstractAbstract
[en] Neutron β-decay is parametrized by several measurable correlation coefficients which are used to determine parameters of the Standard Model and to search for new physics. The aim of the retardation spectrometer aSPECT is to measure the electron-antineutrino angular correlation coefficient a with an unprecedented accuracy of well below 1%. The coefficient is extracted from a high precision measurement of the proton energy spectrum. A central point of this PhD thesis is the analysis of the background, motivated by the observations of discharges during the beam time of 2011, and an earlier indication for a dependence on the retardation potential. During this thesis, several measurements were conducted off-line, without ionizing particles from neutron decay. An 'internal' background (X-rays and ions) was identified. It has an influence of 10-5 to 10-4 on Δa/a depending on the vacuum level (∼10-9 mbar) and the spectrometer settings. Within the analysis of the data from the beam time in 2013, a model was built to correct for backgrounds present in neutron decay experiment, taking into account its time dependence. The correction is about 3% on the coefficient for standard settings and vacuum but it can reach 7% for unfavorable settings. To reduce the background, a drift electric field was applied close to the maximum of the retardation potential. Additional measurements performed during this beam time included tests of systematics, in particular the edge effect (beam profile) and different electrode settings. In order to obtain the final result, the analysis has to be extended by including the different corrections and by comparing with simulations of the systematic effects. (author)
Original Title
Mesure du coefficient de correlation angulaire a entre l'electron et l'antineutrino dans la desintegration β du neutron avec le spectrometre aSPECT
Primary Subject
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25 Feb 2014; 185 p; 76 refs.; Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS-NKM website for current contact and E-mail addresses: http://www.iaea.org/inis/Contacts/; Also available from SICD1 BP 66, 38402 Saint-Martin d'Heres Cedex (France); Physique Subatomique et Astroparticules
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Report
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Thesis/Dissertation
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ANTILEPTONS, ANTIMATTER, ANTINEUTRINOS, ANTIPARTICLES, CHARGED PARTICLE DETECTION, CORRELATIONS, DECAY, DETECTION, ELECTRON NEUTRINOS, ELEMENTARY PARTICLES, FERMIONS, FIELD THEORIES, GRAND UNIFIED THEORY, LEPTONS, MASSLESS PARTICLES, MATHEMATICAL MODELS, MATTER, MEASURING INSTRUMENTS, NEUTRINOS, NOISE, NUCLEAR DECAY, PARTICLE MODELS, QUANTUM FIELD THEORY, RADIATION DETECTION, RADIATION DETECTORS, UNIFIED GAUGE MODELS
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Dragolici, Cristian A., E-mail: adrag@nipne.ro2014
AbstractAbstract
[en] Small angle scattering (SAS) is the collective name given to the techniques of small angle neutron (SANS) and X-ray (SAXS) scattering. They offer the possibility to analyze particles without disturbing their natural environment. In each of these techniques radiation is elastically scattered by a sample and the resulting scattering pattern is analyzed to provide information about the size, shape and orientation of some component of the sample. Accordingly, a large number of methods and experimental patterns have been developed to ease the investigation of condensed matter by use of these techniques. Some of them are the discussed in this paper
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TIM-13 Physics Conference; Timisoara (Romania); 21-24 Nov 2013; (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
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AbstractAbstract
[en] The Indexing HDMR method was recently developed for modelling multivariate interpolation problems. The method uses the Plain HDMR philosophy in partitioning the given multivariate data set into less variate data sets and then constructing an analytical structure through these partitioned data sets to represent the given multidimensional problem. Indexing HDMR makes HDMR be applicable to classification problems having real world data. Mostly, we do not know all possible class values in the domain of the given problem, that is, we have a non-orthogonal data structure. However, Plain HDMR needs an orthogonal data structure in the given problem to be modelled. In this sense, the main idea of this work is to offer various forms of Indexing HDMR to successfully model these real life classification problems. To test these different forms, several well-known multivariate classification problems given in UCI Machine Learning Repository were used and it was observed that the accuracy results lie between 80% and 95% which are very satisfactory
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ICNPAA 2014: 10. International Conference on Mathematical Problems in Engineering, Aerospace and Sciences; Narvik (Norway); 15-18 Jul 2014; (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
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AbstractAbstract
[en] To solve the electromagnetic scattering problem in two dimensions, the Finite Difference Time Domain (FDTD) method is used. The order of convergence of the FDTD algorithm, solving the two-dimensional Maxwell’s curl equations, is estimated in two different computer implementations: with and without an obstacle in the numerical domain of the FDTD scheme. This constitutes an electromagnetic scattering problem where a lumped sinusoidal current source, as a source of electromagnetic radiation, is included inside the boundary. Confined within the boundary, a specific kind of Absorbing Boundary Condition (ABC) is chosen and the outside of the boundary is in form of a Perfect Electric Conducting (PEC) surface. Inserted in the computer implementation, a semi-norm has been applied to compare different step sizes in the FDTD scheme. First, the domain of the problem is chosen to be the free-space without any obstacles. In the second part of the computer implementations, a PEC surface is included as the obstacle. The numerical instability of the algorithms can be rather easily avoided with respect to the Courant stability condition, which is frequently used in applying the general FDTD algorithm
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ICNPAA 2014: 10. International Conference on Mathematical Problems in Engineering, Aerospace and Sciences; Narvik (Norway); 15-18 Jul 2014; (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
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AbstractAbstract
[en] This paper presents a motion tracking and control system for automatically landing Unmanned Aerial Vehicles (UAVs) on an oscillating platform using Laser Radar (LADAR) observations. The system itself is assumed to be mounted on a ship deck. A full nonlinear mathematical model is first introduced for the UAV. The ship motion is characterized by a Fourier transform based method which includes a realistic characterization of the sea waves. LADAR observation models are introduced and an algorithm to process those observations for yielding the relative state between the vessel and the UAV is presented, from which the UAV's state relative to an inertial frame can be obtained and used for feedback purposes. A sliding mode control algorithm is derived for tracking a landing trajectory defined by a set of desired waypoints. An extended Kalman filter (EKF) is proposed to account for process and observation noises in the design of a state estimator. The effectiveness of the control algorithm is illustrated through a simulation example
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ICNPAA 2014: 10. International Conference on Mathematical Problems in Engineering, Aerospace and Sciences; Narvik (Norway); 15-18 Jul 2014; (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
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Słabkowska, K.; Szymańska, E.; Polasik, M.; Rzadkiewicz, J.; Syrocki, Ł.; Pereira, N. R., E-mail: ninorpereira@gmail.com2014
AbstractAbstract
[en] Ultrafast molybdenum wire implosions on the Z machine at Sandia produce intense pulses of multi-keV x-rays from partially ionized plasmas. The most intense radiation comes from a hot, dense core of thermal plasma in ionization equilibrium with Mo ionized to within the L-shell. Non-thermal, energetic electrons in the plasma generate Kα and Kβ radiation, whose energy is affected by Mo’s ionization state, and therefore on the plasma temperature. Based on an extensive series of recent computations on this effect, we recalculate the pinch’ Mo x-ray spectrum, with reasonable results
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9. International Conference on Dense Z Pinches; Napa, CA (United States); 3-7 Aug 2014; (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
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Velikovich, A. L.; Giuliani, J. L.; Zalesak, S. T., E-mail: sasha.velikovich@nrl.navy.mil, E-mail: sasha.velikovich@nrl.navy.mil2014
AbstractAbstract
[en] The MagLIF approach to inertial confinement fusion involves subsonic/isobaric compression and heating of a DT plasma with frozen-in magnetic flux by a heavy cylindrical liner. The losses of heat and magnetic flux from the plasma to the liner are thereby determined by plasma advection and gradient-driven transport processes, such as thermal conductivity, magnetic field diffusion and thermomagnetic effects. Theoretical analysis based on obtaining exact self-similar solutions of the classical collisional Braginskii's plasma transport equations in one dimension demonstrates that the heat loss from the hot plasma to the cold liner is dominated by the transverse heat conduction and advection, and the corresponding loss of magnetic flux is dominated by advection and the Nernst effect. For a large electron Hall parameter ωeτe effective diffusion coefficients determining the losses of heat and magnetic flux are both shown to decrease with ωeτe as does the Bohm diffusion coefficient, which is commonly associated with low collisionality and two-dimensional transport. This family of exact solutions can be used for verification of codes that model the MagLIF plasma dynamics
Primary Subject
Source
9. International Conference on Dense Z Pinches; Napa, CA (United States); 3-7 Aug 2014; (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
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Muñoz, C. Gonzalo; Valenzuela, Vicente; Veloso, Felipe; Favre, Mario; Wyndham, Edmund, E-mail: gamunoz2f@uc.cl, E-mail: fveloso@fis.puc.cl, E-mail: gamunoz2f@uc.cl, E-mail: fveloso@fis.puc.cl, E-mail: gamunoz2f@uc.cl, E-mail: fveloso@fis.puc.cl, E-mail: gamunoz2f@uc.cl, E-mail: fveloso@fis.puc.cl, E-mail: gamunoz2f@uc.cl, E-mail: fveloso@fis.puc.cl2014
AbstractAbstract
[en] Plasma formation and dynamics from conical wire array is experimentally studied. Ablation from the wires is observed, forming plasma accumulation at the array axis and subsequently a jet outflow been expelled toward the top of the array. The arrays are composed by 16 equally spaced 25μ diameter tungsten wires. Their dimensions are 20mm height, with base diameters of 8mm and 16mm top diameter. The array loads are design to be overmassed, hence no complete ablation of the wires is observed during the current rise. The experiments have been carried out in the Llampudken. pulsed power generator (∼350kA in ∼350ns). Plasma dynamics is studied in both side-on and end-on directions. Laser probing (shadowgraphy) is achieved using a frequency doubled Nd:YAG laser (532nm, 12ps FWHM) captured by CCD cameras. Pinhole XUV imaging is captured using gated microchannel plate cameras with time resolution ∼5ns. Results on the jet velocity and the degree of collimation indicating the plausibility on the use of these jets as comparable to the study astrophysically produced jets are presented and discussed
Primary Subject
Source
9. International Conference on Dense Z Pinches; Napa, CA (United States); 3-7 Aug 2014; (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
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Geyer, Sabrina; Meusel, Oliver; Kester, Oliver, E-mail: geyer@iap.uni-frankfurt.de, E-mail: geyer@iap.uni-frankfurt.de2015
AbstractAbstract
[en] Electron-ion interaction processes are of fundamental interest for several research fields like atomic and astrophysics as well as plasma applications. To address this topic, a transverse electron target based on the crossed beam technique was designed and constructed for the application in storage rings. Using a sheet beam of free electrons in crossed beam geometry promises a good energy resolution and gives access to the interaction region for spectroscopy. The produced electron beam has a length of 10 cm in ion beam direction and a width in the transverse plane of 5 mm. Therewith, electron densities of up to 109 electrons/cm3 are reachable in the interaction region. The target allows the adjustment of the electron beam current and energy in the region of several 10 eV to a few keV. Simulations have been performed regarding the energy resolution for electron-ion collisions and its influence on spectroscopic measurements. Also, the effect on ion-beam optics due to the space charge of the electron beam was investigated. Presently the electron target is integrated into a test bench to evaluate its performance for its dedicated installation at the storage rings of the FAIR facility. Therefore, optical diagnostics of the interaction region and charge state analysis with a magnetic spectrometer is used. Subsequently, the target will be installed temporarily at the Frankfurt Low-Energy Storage Ring (FLSR) for further test measurements
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12. International Symposium on Electron Beam Ion Sources and Traps; East Lansing, MI (United States); 18-21 May 2014; (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
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