Abstract China has contributed to the manufacturing of the Error Field Correction Coils (CC) and the Magnet Feeders for ITER (International Thermonuclear Experimental Reactor). The manufacturing ...projects have been carried by ASIPP (Institute of Plasma Physics Chinese Academy of Sciences). In this paper, the lessons learned from these two manufacturing projects will be described with special focus on some key manufacturing processes. These experiences gained from the work carried so far in CC and magnet feeder manufacturing and testing are very valuable not only for the remaining manufacturing tasks of these two projects, but also for similar systems of other Tokamak fusion device.
International Thermonuclear Experimental Reactor (ITER) is the largest global cooperation project, which will be built as the world's largest tokamak to explore the commercial production of ...fusion-based electricity. In order to connect the busbars electrically and hydraulically, the "shaking hands" twin-box type joint was designed and implemented for ITER project. Different from the conventional method, the indium bonding technology was developed instead of the Tin soldering method for the joint connection. In order to qualify for the ITER correction coil (CC) feeder joint structure and the manufacturing technology, Institute of Plasma Physics, Chinese Academy of Science (ASIPP) has launched the joint qualification on the manufacture process and the cryogenic performance. By means of the indium bonding, the joint resistance can be lower than 1 nΩ before and after the mechanical fatigue. This paper reports the structure and manufacturing process of CC feeder joint, describes the establishing of the testing setup, and finally discusses the cryogenic testing results. Besides the joint resistance, the pressure drop and the critical temperature are reported.
The Chinese Domestic Agency (DA) is procuring ITER Enhanced Heat Flux (EHF) First Wall (FW) panels which shall withstand a surface heat load up to 4.7 MW/m2 during ITER operation. Prior to the ...implementation of the ITER Procurement Arrangement (PA), several key technologies in manufacturing the EHF FW panel have been qualified. In the pre-PA task, ITER grade CN-G01 high-purity beryllium has been developed; its chemical composition, mechanical properties and grain size satisfy the ITER requirements. The strict quality control in the manufacturing of bimetallic plate was aimed at increasing the reliability the reliability of hypervapotron (HVT) heat sink for the EHF FW fingers, while a design improvement of the HVT cooling channel improved the thermal fatigue performance. Investigation showed that magnetron sputtering Ti/Cu coating on the beryllium tiles helps in reducing possible defects and results in better quality of Be-Cu hot isostatic press (HIP) bonding interfaces. As a result of such measures, China completed two EHF FW semi-prototypes with one successfully passing the high heat flux test (HHFT) at 4.7 MW/m2 for 7500 cycles and 5.9 MW/m2 for 1500 cycles. Neither damage to the semi-prototype nor off-normal surface temperature increase was observed, which brought the semi-prototype qualification campaign to a successfully conclusion.
To carry current for the ITER correction coils, the 10-kA high-temperature superconducting current leads studied here are designed. Current leads provide the transition from 4.5-K low temperature to ...room temperature. This paper summarizes the major design features of the prototypes, which is followed by a discussion of the manufacturing and testing. The test results approved their excellent performance on low joint resistance and long loss-of-flow accident time. The overheating time, mass flow, and heat loads to 5-K ends also reached the expectation.
The Magnet Feeder system in the International Thermonuclear Experimental Reactor (ITER) deploys electrical currents and supercritical helium to the superconducting magnets and the magnet diagnostic ...signals to the operators. In the current design, the feeders located in the upper L3 level of the Tokamak gallery penetrate the Tokamak coolant water system vault, the biological shield and the cryostat. As a secondary confinement to contain the activated coolant water in the vault in the case of water pipe burst accident, a water barrier is welded between the penetration in the water pipe chase outer wall and the mid-plane of the vacuum jacket of the Feeder Coil Terminal Box (CTB). A thin-wall stainless steel diaphragm with an omega shape profile is welded around the CTB as the water barrier to endure 2bar hydraulic pressure. In addition, the barrier is designed as a flexible compensator to withstand a maximum of 15mm of axial displacement of the CTB in case of helium leak accident without failure. This paper presents the detail configuration, the manufacturing and assembly processes of the water barrier. Test results of the prototype water barrier under simulated accident conditions are also reported. Successful qualification of the design and manufacturing process of the water barrier lays a good foundation for the series production of this subsystem.
Design and Technology Preparation for the ITER HTSCL Tingzhi Zhou; Kun Lu; Qingxiang Ran ...
IEEE transactions on applied superconductivity,
06/2014, Letnik:
24, Številka:
3
Journal Article, Conference Proceeding
Recenzirano
ASIPP will supply for ITER all the current leads. There are three types of high temperature superconducting (HTS) current leads designed to carry 68 kA, 55 kA, or 10 kA to the ITER magnets. Different ...from the trial leads manufactured and tested in Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), some critical technologies were qualified before the manufacturing of the ITER leads could commence, including: 1) welding, brazing, and soldering qualification; 2) fin type heat exchanger (HEX) with tight assembly tolerance; 3) low temperature superconducting (LTS) linker with cables soldered to the 5 K copper terminal; 4) instrumentation mock-up for the temperature and voltage test. In this paper, the outcome of these qualification activities will be reported together with the plans for the series production planning and development.
Ta-N thin films were deposited on AISI 317L stainless steel (SS) substrates by cathodic arc deposition (CAD) at substrate biases of -50 and -200V. The as-deposited films were characterized using ...X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray analysis (EDX). The results show that stoichiometric TaN with hexagonal lattice (300) preferred orientation was achieved at the bias of -200V. On the other hand, Ta-rich Ta-N thin film deposited at -50V shows amorphous nature. According to the XPS result, Ta element in the films surface exist in bonded state, including the Ta-N bonds characterized by the doublet (Ta 4f7/2=23.7eV and Ta 4f5/2=25.7eV). Electrochemical properties of the Ta-N coated stainless steel systems were investigated using potentiodynamic polarization and electrochemical impedance spectroscope (EIS) in Hank's solution at 37 deg C. For the Ta-N coated samples, the corrosion current (icorr) is two or three orders of magnitude lower than that of the uncoated ones, indicating a significantly improved corrosion resistance. Growth defects in the Ta-N thin films produced by CAD, however, play a key role in the corrosion process, especially the localised corrosion. Using the polarization fitting and the EIS modelling, we compared the polarization resistance (Rp) and the porosity (P) of the Ta-N coatings deposited at different biases. It seems that Ta-N film with comparatively lower bias (-50V) shows better corrosion behavior in artifical physiological solution. That may be attributed to the effect of ion bombarding, which can be modulated by the substrate bias.
The ITER Feeder is an important subsystem, which transmits the electrical power to the ITER Tokamak magnet system. In the Feeder, all the HV potential components, including the current leads, the ...busbars, and the joints, need to be insulated with solid composite materials to electrically isolate the HV potential from ground. Based on over three years of preliminary qualification and experimental comparison, the prepreg tape and relevant curing techniques were finally chosen as the formal feeder insulation material and method. The formal insulation qualification was launched, including the material qualification and the component qualification. Now the static tensile/shear strength, the fatigue tensile strength, the compression-shear strength, the push-out strength and the void content test for the prepreg material qualification has been completed. This paper describes the whole research improvement of ITER feeder electrical insulation qualification activities, introduces the selection of procured materials and the manufacturing trials, and summarizes the formal qualification items and their test results.
•Vacuum brazing and electron beam welding qualification.•Machine and assembly strategy of fin type heat exchanger.•Soldering and joint resistance test of superconducting joint.•Pre-preg technology ...with vacuum bag on insulation.
Three types of high temperature superconducting current leads (HTSCL) are designed to carry 68kA, 55kA or 10kA to the ITER magnets. Before the supply of the HTS current lead series, the design and manufacturing process is qualified through mock-ups and prototypes. Seven mock-ups, representing the critical technologies of the current leads, were built and tested successfully in the Institute of Plasma Physics of the Chinese Academy of Sciences (ASIPP) in 2013. After the qualification some design features of the HTS leads were updated. This paper summarizes the qualification through mock-ups. In 2014 ASIPP started the manufacture of the prototypes. The preparation and manufacturing process are also described.
