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The precompression ring (PCR) is an important element of the ITER magnetic system since it improves the force distribution among the toroidal field magnets during plasma operation. An experimental campaign has been planned at the ITER organization to characterize themechanical behavior of the ring in a test rig able to simulate the ITER assembly conditions. In particular, the testing machine aims at simulating the effect of the preload by means of a system of hydraulic cylinders capable to deliver 36 000 tons of radial pushing force. A steel "cushion" flange acts as interface between the cylinders and the ring distributing the pressure on the surface and preventing the PCR from local breakage. In this paper, the shape optimization of such flange is addressed, identifying the optimal geometry basing on the contact stress on the inner surface of the PCR. The study shows how the stress peaks can be avoided by obtaining a reasonably homogeneous distribution limiting the risks of peak stresses that might compromise the integrity of the component. The results of this study can also be used as a basis of future studies aiming at optimizing the ITER flange design and the behavior of the PCR in operative conditions. [ABSTRACT FROM AUTHOR]

The magnet system is one of the critical core components of the ITER magnets, defining the machine capabilities to form and drive 15 MA 500 MW nuclear plasmas for hundreds of seconds. The magnets, the largest superconducting magnet system ever built with 50 GJ of stored energy, are technologically highly advanced components using large composite Nb3Sn 4–6 K force flow cooled conductors that, in order to maximise plasma performance and minimise cost, stretch current manufacturing technology to its limits. They work at the highest possible electrical (20–30 kV), mechanical (primary stresses up to 600 MPa) and superconducting performance consistent with very safe and very reliable operation over the life of the machine. The magnets, and the associated feeder system, are now entering the final manufacturing stages. Almost all prototyping and qualification work is completed, the sub-components such as the conductors are nearly fully manufactured (over 80% complete), some of the coil production lines are nearly fully ‘loaded’ and in several cases the ‘first of a kind’ final winding packs are nearing completion. In this article we review the main manufacturing difficulties that have been overcome, summarise the present production status of the magnets and describe the coming challenges of testing and assembly. [ABSTRACT FROM AUTHOR]

The feeder design has been improved by the feeder teams at the ITER Organization (IO) and the Institute of Plasma Physics, Chinese Academy of Science (ASIPP) by incorporating the results of mechanical and thermal analyses as well as the system integration and assembly tolerances in the present CAD model. The feeder design is being finalized progressively, and will be delivered to the Chinese Domestic Agent (CNDA) for further procurement arrangement (PA) activities. Pre-PA manufacturing studies and tests performed at ASIPP have been effective in clarifying feeder design feasibility and component manufacturability. This paper reports the recent advancements on feeder design, analysis and manufacturing studies. [ABSTRACT FROM PUBLISHER]

The Procurement of the feeder system for The International Thermonuclear Experimental Reactor (ITER) tokamak device started in ASIPP (China) in 2006. The relevant tasks of structural design and analysis have now come to an end, but the R&D activities started in 2009 for critical feeder components and key technology are still ongoing. Following the signature of the Procurement Arrangement between China and the ITER Organization (IO) in 2010, a great number of R&D tasks have been launched with the purpose of testing and verifying the original design, leading to design changes and optimizations. This paper mainly discusses the progress of the feeder design and R&D activities; it also presents some test results. [ABSTRACT FROM PUBLISHER]

This paper summarizes the results of the static structural analyses, which were conducted in support of the ITER magnet feeder design with the aim of validating certain components against the structural design criteria. While almost every feeder has unique features, they all share many common constructional elements and the same functional specifications. The analysis approach to assess the load conditions and stresses that have driven the design is equivalent for all feeders, except for particularities that needed to be modeled in each case. The mechanical analysis of the feeders follows the sub-modeling approach: the results of the global mechanical model of a feeder assembly are used as input for the detailed models of the feeder' sub-assemblies or single components. Examples of such approach, including the load conditions, stress assessment criteria and solutions for the most critical components, are discussed. It has been concluded that the feeder system is safe in the referential operation scenarios. [ABSTRACT FROM PUBLISHER]

Following the design, fabrication and test of a series of trial leads, designs of the three types of current leads required for ITER have been developed, and targeted trials of specific features are in progress on the way to fabrication and testing of prototype units. These leads are of the hybrid type with a cold section based on the use of high temperature superconductor (HTS) and a resistive section cooled by forced flow of helium gas, optimized for operation at 68 kA, 55 kA and 10 kA. The leads incorporate relevant features of the large series of current leads developed and constructed for the CERN-LHC, relevant features of the trial leads built for ITER, and additional features required to fully satisfy the exigent constraints of ITER with regard to cooling, insulation, and interfaces to feeder and powering systems. In this report a description of the design of the leads is presented, together with plans for the preparation of prototype manufacture and testing at ASIPP. [ABSTRACT FROM PUBLISHER]

The ITER Superconducting Magnet Manufacturing Database, MMD, is not only a data archive, but also a common communication platform, on which contributors to magnet manufacturing collaborate and take coordinated actions. In-kind procurement is a feature of the ITER construction. The magnet system construction involves six Domestic Agencies (DAs) plus contractors in these DAs. The six DAs are EU, Japan, Russia, the USA, Korea and China. The magnet system consists of many components like TF coils and current feeders. The ITER Organization (IO) monitors and controls quality throughout the manufacturing process. This is fundamental because the IO takes responsibility for the ITER machine even though not all large components can be tested under nominal conditions before their acceptance. For many contributors though (who have different cultures, quality assurance systems and languages), quality monitoring and control (QA/QC) represent big challenges. [ABSTRACT FROM AUTHOR]

At least two independent methods for quench detection should be used for the magnets of the ITER size, because of the potential severe impact of a failure. The voltage tape method and the flow meter method, which were used in the CS model coil (CSMC), are both considered for the ITER Central Solenoid (CS). The voltage tap method is primary due to its quick response. The ITER CS consists of six pancake wound modules, which are operated with individual operating current patterns in ac mode. The induced voltage in the windings must be compensated to detect the voltage due to any normal transition during the pulse operation. We have investigated the optimum configuration for pick-up coils (PC) for compensation. The results of simulations show that the compensated voltages are very low (70 mV) compared with the inductive voltage and adequate normal voltage sensitivity is obtained. The hot spot temperature in the CS during the operation was estimated from the simulation and the experimental measurements of the CSMC quench. The hot spot temperature estimated is 128-144 K, lower than the ITER design criterion (150 K). It is shown that the detection system using the PCs could be designed with a high enough detection sensitivity. [ABSTRACT FROM AUTHOR]

Abstract: The design status of the main ITER magnet structures and the toroidal field (TF) coil cases, is described. In the last 3 years, the major geometry of the TF coil case has remained unchanged, but significant improvements have been made to the structural support, to the material options and main fabrication steps. The lack of access for inspection and repair means a high reliability is required, and appropriate codes and standards to control the manufacturing have been defined. The structural assessment shows that the design and operational criteria can be satisfied with reasonable inspection criteria. [Copyright &y& Elsevier]