[en] Highlights: • Thermal design requirements for EAST RMP coils are summarized. • Cooling parameters based on both theoretical and numerical solutions are determined. • Compromise between thermal design and structural design is made on number of turns. • Thermo-mechanical calculations are made to validate its structural performance. - Abstract: Resonant magnetic perturbation (RMP) has been proved to be an efficient approach on edge localized modes (ELMs) control, resistive wall mode (RWM) control, and error field correction (EFC), RMP coil system under design in EAST tokamak will realize the above-mentioned multi-functions. This paper focuses on the thermo-mechanical analysis of EAST RMP coil system on the basis of sensitivity analysis, both normal and off-normal working conditions are considered. The most characteristic set of coil system is chosen with a complete modelling by means of three-dimensional (3D) finite element method, thermo-hydraulic and thermal-structural performances are investigated adequately, both locally and globally. The compromise is made between thermal performance and structural design requirements, and the results indicate that the optimized design is feasible and reasonable

[en] A kind of dielectric barrier discharge (DBD) device composed of water electrodes with 3 × 3 forms can produce large-area low-temperature plasmas at atmospheric pressure. To reflect the discharge characteristics of DBD better, a dynamic simulation model, which is based on the voltage controlled current source (CCS), is established, then the established model in Matlab/Simulink is used to simulate the DBD in air. The voltage–current waves and Lissajous at a voltage of 10 kV, 11 kV and 12 kV peak value with a frequency of 15 kHz are studied. The change of the discharge power of DBD with a different amplitude and frequency of applied voltage is also analyzed. The result shows the voltage–current waves, Lissajous and discharge power of DBD under different conditions from the simulation agree well with those of the experiment. In addition, we propose a method to calculate the dielectric barrier capacitance $C_{\mathrm{d}}$ and the gap capacitance $C_{\mathrm{g}},$ which is valid through analyzing the variation of capacitance at different voltage amplitudes. (paper)

[en] In-vessel components are important parts of the EAST superconducting tokamak. They include the plasma facing components, passive plates, cryo-pumps, in-vessel coils, etc. The structural design, analysis and related R and D have been completed. The divertor is designed in an up-down symmetric configuration to accommodate both double null and single null plasma operation. Passive plates are used for plasma movement control. In-vessel coils are used for the active control of plasma vertical movements. Each cryo-pump can provide an approximately 45 m³/s pumping rate at a pressure of 10^-1 Pa for particle exhaust. Analysis shows that, when a plasma current of 1 MA disrupts in 3 ms, the EM loads caused by the eddy current and the halo current in a vertical displacement event (VDE) will not generate an unacceptable stress on the divertor structure. The bolted divertor thermal structure with an active cooling system can sustain a load of 2 MW/m² up to a 60 s operation if the plasma facing surface temperature is limited to 1500 deg. C. Thermal testing and structural optimization testing were conducted to demonstrate the analysis results.

[en] For safe operation with active water cooling plasma facing components (PFCs) to handle a large input power over a long pulse discharge, some design optimization, R and D and maintenance were accomplished to improve the in-vessel components. For the purpose of large plasma current (1 MA) operation, the previous separated top and bottom passive stabilizers in the low field were electrical connected to stabilize plasma in the case of vertical displace events (VDEs). The design and experiments are described in this paper

[en] Highlights: • The functional analysis of EAST upper full tungsten divertor cooling system was performed. • A failure modes, effects and criticality analysis of EAST upper full tungsten divertor cooling system was performed. • The reliability and availability of EAST upper full tungsten divertor cooling system and its main functions were calculated. • RAMI analysis approach was applied to EAST upper full tungsten divertor cooling system for its technical risk evaluation. - Abstract: EAST (Experimental Advanced Superconducting Tokamak) device is a D-shaped full superconducting tokamak with actively water cooled plasma facing components. As the EAST project technical risk control and possible failure mitigation approach, RAMI (Reliability, Availability, Maintainability and Inspectability) analysis was required for the upper full tungsten divertor water cooling system, which insures the system to cool the PFCs with high efficient and safety without leakage. At the same time the cooling water could be at suitable pressure, temperature and velocity, water parameters of cooling circuit also could be monitored. A functional breakdown was prepared and all functions are described using the IDEFØ (Integration DEfinition Function – language Ø) method. FMECA (Failure Mode, Effects and Criticality Analysis) was performed to the system initial risk. There are 31 risks for the initial state, including 7 major risks. No major risk remains after taking into account all the actions. RBDs (Reliability Block Diagrams) were prepared to calculate the reliability and availability of each function. The initial availability of upper divertor cooling water system was 93.63%, after optimization the expected availability was 98.56% over 11,520 h. It was assessed that the upper full tungsten divertor water cooling system RAMI analysis results meet the EAST project requirement during this design phase and the results will be qualified further when the system design is updated.