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Nakano, Tomohide; Shumack, A.*; Maggi, C. F.*; Reinke, M.*; Lawson, K.*; Coffey, I.*; Ptterich, T.*; Brezinsek, S.*; Lipschultz, B.*; Matthews, G. F.*; et al.
Journal of Physics B; Atomic, Molecular and Optical Physics, 48(14), p.144023_1 - 144023_11, 2015/07
Times Cited Count:38 Percentile:86.22(Optics)The and
3p-4d inner shell excitation lines in addition to
2p-3s lines have been identified from the spectrum taken by an upgraded high-resolution X-ray spectrometer. It is found from analysis of the absolute intensities of the
and
lines that W and Mo concentrations are in the range of
and
, respectively, with a ratio of
5% for ELMy H-mode plasmas with a plasma current of 2.0- 2.5 MA, a toroidal magnetic field of 2.7 T and a neutral beam injection power of 14-18 MW. For the purpose of checking self-consistency, it is confirmed that the W concentration determined from the
line is in agreement with that from the
line within 20% and that the plasma effective charge determined from the continuum of the first order reflection spectrum is also in agreement with that from the second order within 50%. Further, the determined plasma effective charge is in agreement with that determined from a visible spectroscopy, confirming that the sensitivity of the X-ray spectrometer is valid and that probably the W and the Mo concentrations are also valid.
Cooper, W. A.*; Brunetti, D.*; Faustin, J. M.*; Graves, J. P.*; Pfefferl, D.*; Raghunathan, M.*; Sauter, O.*; Tran, T. M.*; Chapman, I. T.*; Ham, C. J.*; et al.
Nuclear Fusion, 55(6), p.063032_1 - 063032_8, 2015/05
Times Cited Count:2 Percentile:8.34(Physics, Fluids & Plasmas)An approximate model for a single fluid 3D MHD equilibrium with pure isothermal toroidal flow with imposed nested magnetic flux surfaces is proposed. It recovers the rigorous toroidal rotation equilibrium description in the axisymmetric limit. The approximation is valid under conditions of nearly rigid or vanishing toroidal rotation in regions with 3D deformation of the equilibrium flux surfaces. Bifurcated helical core equilibrium simulations of long-lived modes in the MAST device demonstrate that the magnetic structure is only weakly affected by the flow but that the 3D pressure distortion is important. The pressure is displaced away from the major axis and therefore is not as noticeably helically deformed as the toroidal magnetic flux under the subsonic flow conditions. Fast particle confinement is investigated with the VENUS code. In the presence of toroidal flow, the drift orbit equations depend on the electrostatic potential associated with the rotation and quasineutrality at lowest order in Larmor radius. When the equilibrium has 3D deformations, geometrical terms appear from the evaluation of Ohm's Law that considerably complicates the description of fast particle confinement.
Asayama, Tai; Jetter, R.*
Proceedings of 2008 ASME Pressure Vessels and Piping Division Conference (PVP 2008) (CD-ROM), 9 Pages, 2008/07
Renewed interest in elevated temperature nuclear reactors has occasioned a reassessment of creep-fatigue damage evaluation methods. Points to be improved in the current methods employed in Subsection NH of the ASME Boiler and Pressure Vessel Code and other design codes are discussed. Most current creep-fatigue damage evaluation methods separately evaluate cyclic fatigue damage and creep damage and assess the combined damage through interaction diagrams. In this paper, an alternate approach to determination of cyclic life has been proposed which avoids parsing the damage into creep and fatigue components. This approach, called the Simplified Model Test (SMT) has two major advantages. First, it is not necessary to calculate the inelastic stress-strain history for a design evaluation. Second, it is not necessary to rely on theoretical modeling of these effects in an artificial separate accounting of creep and fatigue damage.