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[en] Highlights: • A multi-scenario force-calculating simulator for Tokamak magnet system is developed using interaction matrix method. • The simulator is applied to EM analysis of CFETR and EAST magnet system. • The EM loads on CFETR magnet coils at different typical scenarios and the EM loads acting on magnet system of EAST as function of time for different shots are analyzed with the simulator. • Results indicate that the approach can be conveniently used for multi-scenario and real-time EM analysis of Tokamak magnet system. - Abstract: A technology for electromagnetic (EM) analysis of the current-carrying components in tokamaks has been proposed recently (Rozov, 2013; Rozov and Alekseev, 2015). According to this method, the EM loads can be obtained by a linear transform of given currents using the pre-computed interaction matrix. Based on this technology, a multi-scenario force-calculating simulator for Tokamak magnet system is developed using Fortran programming in this paper. And the simulator is applied to EM analysis of China Fusion Engineering Test Reactor (CFETR) and Experimental Advanced Superconducting Tokamak (EAST) magnet system. The pre-computed EM interaction matrices of CFETR and EAST magnet system are implanted into the simulator, then the EM loads on CFETR magnet coils at different typical scenarios are evaluated with the simulator, and the comparison of the results with ANSYS method results validates the efficiency and accuracy of the method. Using the simulator, the EM loads acting on magnet system of EAST as function of time for different shots are further analyzed, and results indicate that the approach can be conveniently used for the real-time EM analysis of Tokamak magnet system.
[en] Detailed design of the vacuum feedthrough for the ion cyclotron radio frequency (ICRF) antenna in EAST, along with an electro-analysis and thermal structural analysis, is presented. The electric field, the voltage standing wave ratio (VSWR) and the stresses in the vacuum feedthrough are studied. A method using the rings of oxygen-free copper as the cushion and macro-beam plasma arc welding is applied in the assembly to protect the ceramic from being damaged during welding. The vacuum leak test on the prototype of vacuum feedthrough is introduced. (fusion engineering)
[en] The HT-7U vacuum vessel is an all-metal welded double wall toroidal structure, which has characteristics of ultra-high vacuum and thin shell. Some of the forming tools will be fabricated according to its outline dimensions. In order to design a optimal shape for the forming tools and avoid an undesirable local deformation at the head of sheet, the software package ANSYS/LS-DYNA and DYNAFORM were utilized to simulate the process of the deep drawing in sheet metal forming and develop a parameter optimization system for the design of the die and punch. During the numerical simulation the updated LaGrange formulation and elastic-plastic constitutive equation were adopted to solve the problem of large strain and large deformation in sheet forming process. According to the simulation analysis results the optimum shape of the die and punch surface was finally determined
[en] It can provide an ultrahigh vacuum location for the plasma operation. In order to improve its vacuum degree and attain a high quality operation environment for plasma, it is very important to proceed 250 degree C baking out to clear the wall before the plasma operation. The paper firstly gives two kinds of structures for the baking of the vacuum vessel, in which one is the baking by electricity and another is baking by the nitrogen gas. Secondly based on the numerical simulation and analysis, some results have been attained such as the baking power, temperature field distribution and thermal stress for the vacuum vessel, which can provide some valuable theory basis for the engineering design and optimization of the baking system of the HT-7U vacuum vessel or other similar super-conducting tokamak devices
[en] Highlights: • A new technology–interaction matrix method is applied to assess EM loads of EAST magnet system. • The interaction matrices of EAST magnet system are obtained. • The application validated the efficiency and accuracy of the method. • Results indicate that the approach can be conveniently used for multi-scenario EM loads assessment for EAST current-carrying components. - Abstract: An approach for assessing the electromagnetic (EM) loads of the main current-carrying components in tokamaks has been proposed recently [1,2]. It is mainly based on the interaction matrix and the method is general. This paper explores on the application of the new technology to EAST magnet system. Firstly, the interaction matrices of EAST magnet composed of bilateral interaction forces between separate components at unit current are calculated, then the EM loads are obtained by a linear transform of given currents using the interaction matrix. The application validated the efficiency and accuracy of the method, which is useful for the systematic assessment of Tokamak EM forces. Results indicate that the approach can be conveniently used for multi-scenario EM assessments and parametric studies of the EM loads for EAST current-carrying components, and a specialized force-calculating module for real-time simulating will be developed in the future.
[en] Highlights: • The electromagnetic and structural responses of VV and PFCs for EAST are analyzed. • A detailed finite element model of the VV including PFCs is established. • The two most dangerous scenarios, major disruptions and downward VDEs are considered. • The distribution patterns of eddy currents, EMFs and torques on PFCs are analyzed. -- Abstract: During plasma disruptions, time-varying eddy currents are induced in the vacuum vessel (VV) and Plasma Facing Components (PFCs) of EAST. Additionally, halo currents flow partly through these structures during the vertical displacement events (VDEs). Under the high magnetic field circumstances, the resulting electromagnetic forces (EMFs) and torques are large. In this paper, eddy currents and EMFs on EAST VV, PFCs and their supports are calculated by analytical and numerical methods. ANSYS software is employed to evaluate eddy currents on VV, PFCs and their structural responses. To learn the electromagnetic and structural response of the whole structure more accurately, a detailed finite element model is established. The two most dangerous scenarios, major disruptions and downward VDEs, are examined. It is found that distribution patterns of eddy currents for various PFCs differ greatly, therefore resulting in different EMFs and torques. It can be seen that for certain PFCs the transient reaction force are severe. Results obtained here may set up a preliminary foundation for the future dynamic response research of EAST VV and PFCs which will provide a theoretical basis for the future engineering design of tokamak devices
[en] Provides a systematic introduction to tokamaks in engineering mechanics. Includes design guides based on full mechanical analysis, which makes it possible to accurately predict load capacity and temperature increases. Presents comprehensive information on important design factors involving materials. Covers the latest advances in and up-to-date references on tokamak devices. Numerous examples reinforce the understanding of concepts and provide procedures for design. Tokamak Engineering Mechanics offers concise and thorough coverage of engineering mechanics theory and application for tokamaks, and the material is reinforced by numerous examples. Chapter topics include general principles, static mechanics, dynamic mechanics, thermal fluid mechanics and multiphysics structural mechanics of tokamak structure analysis. The theoretical principle of the design and the methods of the analysis for various components and load conditions are presented, while the latest engineering technologies are also introduced. The book will provide readers involved in the study of mechanical/fusion engineering with a general understanding of tokamak engineering mechanics.
[en] The EAST (Experimental Advanced Superconducting Tokamak) is an advanced steady-state plasma physics experimental device, which has been approved by the Chinese government and being constructed as the Chinese national nuclear fusion Research project. Vacuum vessel is the location for the operation of plasma as one of the key component for EAST device. During it operation the vacuum vessel will not only endure the electromagnetic force due to the plasma disruption and Halo current but also the pressure of boride water and the thermal stress owing to the 250 deg C baking out by the hot pressure nitrogen gas or the 100 deg C hot wall during plasma operation. The cryostat is a large single walled vessel surrounding the entire Basic Machine with central cylindrical section and two end enclosures, a flat base structure with external reinforcements and dome-shaped lid structure. It provides the thermal barrier with the base pressure of 5x10-4 Pa between the ambient temperature testing hall and the liquid helium cooled superconducting magnet. The thermal shields comprise the vacuum vessel thermal shield (VVTS), between the vacuum vessel and the cold TF coil structures, the cryostat thermal shield (CTS), covering the walls of the cryostat, thereby preventing direct line of sight of the room temperature walls to the cold structures, the vacuum port thermal shields (VPTS) that enclose the port connection ducts. The thermal shields are made of double-wall panels, sandwich structure consist of two stainless steel panels and weld quadrate cooling pipe in between the total surface of the thermal shields is about 351 m2. This paper is a report of the structure design and mechanical analyses on the vacuum vessel, thermal shield and cryostat. According to the allowable stress criteria of ASME, the maximum integrated stress intensity on these key components is less than the allowable design stress intensity 3 Sm. The fabrication for these components was completed in 2004 and has been installed in the position since the end of 2005. The first cooldown of the tokamak was carried out recently. In this report some key R and D and testing results have been presented, which included supporting system and the assembly of the whole vacuum vessel, thermal shield and cryostat. (author)
[en] The HT-7U vacuum vessel is an all-metal-welded double-wall interconnected with toroidal and poloidal stiffening ribs. The channels formed between the ribs and walls are filled with boride water as a nuclear shielding. On the vessel surface facing the plasma are installed cable-based Ohmic heaters. Prior to plasma operation the vessel is to be baked out and discharge cleaned at about 250 degree C. During baking out the non-uniformity of temperature distribution on the vacuum vessel will bring about serious thermal stress that can damage the vessel. In order to determine and optimize the design of the HT-7U vacuum vessel, a three-dimensional finite element model was performed to analyse its temperature field and thermal stress. the maximal thermal stress appeared on the round of lower vertical port and maximal deformation located just on the region between the upper vertical port and the horizontal port. The results show that the reinforced structure has a good capability of withstanding the thermal loads
[en] Based on the abundant experimental data from some big size tokamak device, the driving of HALO current was understood. At the same time the numerical simulation methods was used to investigate the HALO damage to the structure of tokamak device considering the toroidal asymmetric characteristic of the HALO current. Finally an engineering theory and science analysis method will be summarized, which could help to develop the design criteria for the future tokamak fusion reactors. (authors)