Publications (7)4.09 Total impact
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Conference Proceeding: Plasma disruptions in ITER and the ECH upper port plug design
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ABSTRACT: During ITER operation malfunctions of the control system due to excessively large perturbations and for special configurations can lead to vertical displacement events (VDE), where a vertical plasma movement is followed by a fast or slow plasma current quench. As a result during the plasma breakdown induced eddy and halo currents cause severe loads on the in-vessel components. For the upper port plug (UPP) structures in ITER the upward VDEs with the subsequent fast current quench are the most critical disruptions. The upper port design requires a plug length of about 5 m with a spacing of 10 mm at the first wall to the neighboring panels. One of the major challenges in the port plug design is to remain within the 10 mm gap during the disruption. The presented ECH UPP structural design cycle combines numerical analysis with manufacturing and prototype issues such as complex double wall structures and joining qualities.Plasma Science, 2008. ICOPS 2008. IEEE 35th International Conference on; 07/2008 -
Article: Overview of the ITER EC upper launcher
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ABSTRACT: The ITER electron cyclotron (EC) upper port antenna (or launcher) is nearing completion of the detailed design stage and the final build-to-print design stage will soon start. The main objective of this launcher is to drive current locally to stabilize the neoclassical tearing modes (NTMs) (depositing ECCD inside of the island that forms on either the q = 3/2 or 2 rational magnetic flux surfaces) and control the sawtooth instability (deposit ECCD near the q = 1 surface). The launcher should be capable of steering the focused beam deposition location to the resonant flux surface over the range in which the q = 1, 3/2 and 2 surfaces are expected to be found for various plasma equilibria susceptible to the onset of NTMs and sawteeth. The aim of this paper is to provide the design status of the principal components that make up the launcher: port plug, mm-wave system and shield block components. The port plug represents the chamber that provides a rigid support structure that houses the mm-wave and shield blocks. The mm-wave system comprises the components used to guide the RF beams through the port plug structure and refocus the beams far into the plasma. The shield block components are used to attenuate the nuclear radiation from the burning plasma, protecting the fragile in-port components and reducing the neutron streaming through the port assembly. The design of these three subsystems is described; in addition, the relevant thermo-mechanical and electro-magnetic analyses are reviewed for critical design issues.Nuclear Fusion 04/2008; 48(5):054013. · 4.09 Impact Factor -
Conference Proceeding: Structural integration of the EC wave launcher at the ITER upper port plug
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ABSTRACT: For plasma stabilisation in ITER, a reference design of an electron cyclotron (EC) wave launcher was developed (8 remotely steerable beamlines) and improved by advanced remote and front steering configurations. The key concepts of their structural integration into the port plug environment are presented for assuring efficient neutron and thermal shielding.Infrared and Millimeter Waves and 13th International Conference on Terahertz Electronics, 2005. IRMMW-THz 2005. The Joint 30th International Conference on; 10/2005 -
Article: Design and analysis of the structural components in the ITER ECH upper port plug
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ABSTRACT: The structural components of the ITER ECH upper port plug are presented which integrates the mm-wave beam lines of the front steering launcher for the control of plasma instabilities. The design of the main structure considers two alternatives. Firstly, a double wall configuration for the port plug frame responds to homogeneous baking requirements at 240 °C. Secondly, an alternative frame is presented with a single wall in sections that do not require active cooling. The blanket shield module (BSM) is designed as a double-wall housing with a first wall panel (FWP) and individual shield blocks respecting the open space for the mm-wave beams. The cut-out sections to the design of the FWP and the neighbouring lower regular blanket module are defined for the beams of the actual front steering model. The thermo-mechanical stresses of the FWP and the BSM housing caused by nuclear heating and plasma radiation were analysed for the more severe case of the earlier remote steering (“3/8 RS”) reference model. As a result of the calculations for stationary loads and for transient loads during a typical plasma burn of 400 s, no critical stresses have to be expected in the BSM housing.Fusion Engineering and Design. -
Article: Design and Analysis of Windows and Structural Components for the ITER ECRH Upper Port Plug
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ABSTRACT: The structural design of the ECRH Upper Port Plug is developed to in-tegrate mm-wave systems for both limited and full beam focusing. MCNP models were established which allow the neutronics analysis of neutron streaming, nuclear heating and ongoing radioactivation analy-sis. The first wall panel and the internal shields for which nuclear heat-ing is highest, results from thermo-hydraulic analysis prove the feasi-bility of the established cooling concept. The design of the CVD dia-mond window is based on edge-cooling adapted for large apertures. Worst case stress analysis for extreme launching angles indicates the risk of localised plastic deformation in the copper cuffs of the window. -
Article: Design and analysis of the ECH upper port plug structure at ITER
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ABSTRACT: The ECH Upper Port Plug at ITER is designed for controlling plasma instabilities, with a major emphasis on the stabilisation of neoclassical tearing modes, based on the injection a total of 20 MW mm-wave power at 170 GHz into the plasma. The required targeting of flux surfaces in the range of 0.65 to 0.93 (given in terms of the nor-malised poloidal flux surface coordinate) will be achieved by angular steering in the poloidal direction. The paper describes the integration of the mm-wave system into the upper port plug structure with a special focus given to the current front steering reference design. The launcher structure consists of the blanket shield module closing the gap in the blanket at the port; the port plug frame which houses the internal shield; the closure plate forming primary vacuum boundary; and the launcher back-end following the closure plate up to the final flange for the door placed for transfer to the hot cells. The shielding structure is essentially formed by the blanket shield module and the internal shield. For these subsystems, the conceptual design is presented which includes a spe-cially adapted first wall panel welded to a double-walled housing, dedicated shield blocks formed in encased and/or solid configurations according to space requirements, and the internal shield integrated to the port plug frame. The nuclear shielding performance was analysed on the basis of 3D Monte Carlo calculations with the MCNP code for the radiation transport simulation and activation calculations with the FISPACT inventory code. It was shown for a fusion power of 500 MW and an operation over 0.5 full power years that all sufficiency criteria were fulfilled. Thermo-mechanical stresses in the first wall panel and the housing of the blanket shield module were analysed by FEM ("ANSYS") calculations with transient loads for a typical plasma burn of 400 s using a simplified slice structure. -
Article: Conceptual design of the ECH upper launcher system for ITER
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ABSTRACT: The challenge of developing the conceptual design of the ECH Upper Launcher system for MHD control in the ITER plasmas has been tackled by team of European Associations together with the European Domestic Agency (“F4E”). The launcher system has to meet the following requirements: (a) a mm-wave system extending from the interface to the transmission line up to the target absorption zone in the plasma and performing as an intelligent antenna; (b) a structural system integrating the mm-wave system and ensuring sufficient thermal and nuclear shielding; (c) port plug remote handling and testing capability ensuring high port plug system availability. The paper describes the reference launcher design. The mm-wave system is composed of waveguide and quasi-optical sections with a front steering system. An automated feedback control system is developed as a concept based on an assimilation procedure between predicted and diagnosed absorption location. The structural system consists of the blanket shield module, the port plug frame, and the internal shield for appropriate neutron shielding towards the launcher back-end. The specific advantages of a double walled structure are discussed with respect to adequate baking, to rigidity towards launcher deflection under plasma-generated loads and to removal of thermal loads, including nuclear ones. Basic studies of remote handling (RH) to validate design development are initiated using a virtual reality simulation backed by experimental validation, for which a launcher handling test facility (LHT) is set up as a full scale experimental site allowing furthermore thermohydraulic studies with ITER blanket water parameters.Fusion Engineering and Design.
