In a major milestone for the ITER magnet procurement program China has successfully completed the first manufactured component of the feeder package: the cryostat feedthrough for poloidal field coil #4. The 10-metre, 6.6-tonne component is on its way now to the ITER Organization. Measuring 30- to 50-metres in length, ITER magnet feeders will relay electrical power, cryogenic fluids and instrumentation cables from outside of the machine in to the superconducting magnets, crossing the warm/cold barrier of the machine.   These complex systems are equipped with independent cryostats and thermal shields and packed with a large number of advanced technology components such as the high-temperature superconductor current leads, cryogenic valves, superconducting busbars, and high-voltage instrumentation hardware.   Of the 31 feeders distributed around the vessel—and all supplied by China—six will service the poloidal field coils.   The component that is now en route to ITER is the cryostat feedthrough for poloidal field coil #4—the first magnet component required on site because it needs to be brought into position before the completion of the cryostat base support ring. Two other components—the in-cryostat feeder (nearest the vacuum vessel) and the coil termination box (outside the bioshield)—will complete the feeder that connects to the fourth poloidal field coil.   Despite a simple outward appearance, feeders are complex systems that are equipped with independent cryostats and thermal shields and packed with a large number of advanced technology components (high-temperature superconductor current leads, cryogenic valves, superconducting busbars, high-voltage instrumentation hardware). Feeders are the highways that relay electrical power, cryogenic fluids and instrumentation cables from outside of the machine in to the superconducting magnets. At the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) in July approximately forty scientists and engineers from the ITER Organization, the Chinese Domestic Agency, the European Domestic Agency, ASIPP and suppliers Keye Company and Henxing Company, took part in a milestone ceremony. ITER Director-General Bernard Bigot, who could not be present, sent his "warmest heartfelt congratulations" to the team members from different institutes who had all come together to realize this significant accomplishment according to schedule.   Arnaud Devred, who has led the Superconducting Systems & Auxiliaries Section at ITER for ten years—and who has made the "journey east" dozens of times—voiced his great sense of pride.   "The feeder system involves some of the most difficult and risky manufacturing and assembly processes of the ITER Tokamak, but thanks to the hard work and dedication of the teams at the ITER Organization, at the Chinese Domestic Agency, and at ASIPP and its subcontractors, we learned how to work together and to reconcile our cultural differences to meet the tough technical and quality control standards of the Procurement Arrangement. If we are at this successful point in the program today it is because, at our level and for our scope of the ITER Project, we have been able to develop the good collaborative spirit and mutual trust that has enabled us to overcome hurdle after hurdle and to achieve our common goals. I can only wish that the cryostat feedthrough for poloidal field coil #4 remains a testimony to common will power and shared resilience."    An industrial milestone to be celebrated: late July, representatives of the ITER Organization, the Chinese Domestic Agency, the European Domestic Agency, ASIPP and suppliers gathered the mark the shipment of the first completed magnet component to ITER. The ceremony was especially poignant to Arnaud because he was just one month from leaving ITER to join the Large Hadron Collider Luminosity Upgrade at CERN that calls for the manufacture and installation of niobium-tin (Nb3Sn) dipole and quadrupole magnets—a type of superconductor that is massively used in the toroidal field and central solenoid coils of ITER.    The complete magnet feeder system will weigh more than 1,600 tonnes and integrate more than 60,000 individual components.

It is one thing to know that the cryostat will be 30 metres high and 30 metres in diameter; it is another to see these dimensions translated into reality. In the Cryostat Workshop, as the first tier of the component's lower cylinder is now assembled and readied for welding, the vision is awesome. Look at how tiny the men standing on the scaffolding at the far end appear ...   And imagine how it will feel when tier two is added, effectively doubling the height. The whole section will be more than 10 metres high and the workers will appear even smaller.   The six 60-degree segments, each weighing approximately 40 tonnes, are now precisely positioned, but their alignment must be fine-tuned before welding operations can begin.   In order to reach the required precision in positioning the sectors, the most sophisticated technologies alternate with the most basic tools. ITER cryostat engineer Guillaume Vitupier is seen here next to the manual screw jacks used to fine-tune the segments' alignment. As is often the case with ITER components, the techniques involved alternate between the most sophisticated technologies (like laser tracking) and the most basic tools — manual screw jacks, chain slings and winches that will be used to correct the segment profiles and achieve the required sub-millimetre precision.   Once the long and complex alignment operations are finalized, welding will begin. The six 5-metre-high weld gaps between the segments will be filled and tier one of the cryostat lower cylinder will be complete.   Similar operations will be performed on tier two, whose six sectors are due to leave India in mid-September.   Once the lower cylinder segment is complete (tier one and tier two), it will be encased in an airtight cocoon and, pending assembly, stored in a dedicated area adjacent to the Cryostat Workshop.

Teams in Japan have successfully manufactured the 71-tonne inboard leg of the first toroidal field coil case. Formed from three smaller segments welded together, the completed leg is an achievement that crowns a lengthy research and development program carried out to select the materials, tools, welding procedures and machine finishing processes that guarantee the conformance of this first sub-assembly—and those that will follow—to ITER's rigorous technical specifications and tolerances. The smiles are enough to tell the story. At Mitsubishi Heavy Industries in Futami, Japan, the mood was ebullient on 21 July as staff from QST*, the ITER Organization, Mitsubishi and the European Domestic Agency and its supplier gathered for the fitting test of the first toroidal field coil case segment. Following this key step—during which a cover plate was successfully matched with the inboard leg—the component was packed and is now on its way to Hyundai Heavy Industries in Ulsan, Korea, where it will be fitted to the outboard leg in trial tests. (Hyundai Heavy Industries is responsible for part of coil case fabrication through a contract with QST).   The toroidal field coil cases are giant D-shaped structures that house the toroidal field winding packs and that also have a structural role to play in the machine. Japan is manufacturing 18 coil cases plus one spare: nine of these will house winding packs produced in Japan, while the ten others will be shipped to Italy for the integration of winding packs produced by Europe.   The cases have been challenging components to design and manufacture. The structures must be able to withstand an applied electromagnetic force of as much as 60,000 tonnes and an operating temperature of 4 K—making the choice of high yield strength, fracture-resistant material highly important. The multiyear development program that preceded manufacturing led researchers to the selection of a high-strength fully austenitic stainless steel (316LN) whose nitrogen content was increased to about 0.2 percent, plus a specially developed stainless steel (JJ1) for use in areas that will receive the highest stress to ensure a yield strength of 1,000 MPa and fracture toughness of 180 MPa √m at 4 K.   Following the successful verification of its dimensions and tolerances in Japan at Mitsubishi Heavy Industries, the component has been shipped to Korea, where it will be fitted with its "second half." Case fabrication began in April 2014 with the start of qualification activities.   Toroidal field coil cases will stand 16 metres high when finally completed, but first their individual components must be welded together and machine finished. Ultra-high precision is required, with tolerances of less than 1 mm. (Compared to the permitted welding deformation tolerances for typical large welded structures, this represents a difference of more than one order of magnitude.) Keeping welding deformation under control was a major hurdle especially given the thickness of some areas that exceeds 200 mm. The team rose to the challenge by welding from both the front and back surfaces to counteract welding deformation, and measuring regularly as the work progressed.   The different elements of the D-shaped toroidal field coil assemblies are shown in the insert: the inner winding pack (in green), and the inner (BP, AP) and outer (BU, AU) coil case sub-assemblies. Japan has successfully completed the first inboard leg ("AU") sub-assembly. The team also had to compensate for the effects of thermal contraction caused by changes of temperature in the structure during processing to ensure the final product reached tolerances of less than 1 mm.   It took the combined efforts of QST and its suppliers as well as the ITER Organization to make such challenging requirements a reality. Success was confirmed as the first inboard leg passed fitting tests, during which the inboard segment (with its U-shaped cross section) was fitted for the first time with its corresponding cover plate. Observers were pleased to report that the strict tolerances of ± 0.3 mm were met along the entire 14-metre-long weld groove. It took only about half a day to fit the cover plate on the inboard segment, which is good news for the integration work that must be done in the future on the coil cases after insertion of the winding packs.   The first inboard coil case segment has now reached Hyundai Heavy Industries in Korea, where it will be fitted to the outboard leg (shown as "BU" in the image) in trial tests scheduled to take place in the next couple of months. Upon completion of the tests, the full coil case will be shipped to Europe for integration with the winding pack.   *QST—Japan's National Institutes for Quantum and Radiological Science and Technology—is responsible for all components allocated to Japan by the ITER Organization.  

A first-of-a-kind component reached ITER on Friday 22 August—the pre-production cryopump (PPC) that is the culmination of an intensive research and development program in Europe and more than four years of fabrication. This fully useable pump is the precursor for eight more to come. Last week an exceptional piece of equipment reached the premises of the ITER Organization.   In ITER, six cryopumps will be installed around the ITER vacuum vessel and two others in the cryostat. The main role of these massive pumps is to maintain ultra-high vacuum in the vacuum vessel and cryostat by trapping particles on their charcoal-coated panels, and to extract the helium ash from the fusion reaction along with the "unburned" deuterium and tritium nuclei.   The pre-production cryopump is the keystone of a technical development program that has been underway for approximately 10 years, and that has served to validate design and manufacturing processes and address all technical issues.   Technical Responsible Officer Matthias Dremel explains. "More than 15 high-technology companies in Europe were involved in its manufacturing, in close cooperation with the European Domestic Agency and specialists from the ITER Vacuum Section. The delivery signifies a great success for this collaboration."   The 3.4-metre-tall, 8 tonne pump received on 22 August was built by a consortium formed by the German company Research Instruments and the French company Alsyom. The component will now receive further instrumentation and undergo operational mechanical testing at ITER before it is shipped back to Germany—this time to the Karlsruhe Institute of Technology (KIT).   "We now have a fully useable pump, signifying that all issues have been solved," said Robert Pearce, Head of ITER's Vacuum Section (7th from left). At KIT, a cryogenic facility has been set up to mimic the ITER cryogenic supplies. Tests run there on the cryogenic pumping program will help to prepare the pump control systems in time for First Plasma and subsequent operational phases.   "This delivery achieves an important ITER milestone," says Robert Pearce, Head of ITER's Vacuum Section. "This is the culmination of much innovative and challenging work collaboratively performed by the ITER team, the European Domestic Agency, European industry, and European associations. We now have a fully useable pump, signifying that all issues have been solved."   With the successful completion of this first trial fabrication, work can begin on the next eight ITER cryopumps under the procurement responsibility of the European Domestic Agency.   See the report published by the European Domestic Agency at this link.   Click here to view a video of the delivery.

In ITER, scientists will use over 50 diagnostic systems to accurately "read" the plasma and furnish information that is important to its control, evaluation and optimization. All seven ITER Domestic Agencies are involved in the development and procurement of these systems, some of which will have to be installed and operational at the time of the project's First Plasma in 2025. As part of its contributions to ITER diagnostics, the Indian Domestic Agency will be supplying several sub-systems of electron cyclotron emission (ECE) diagnostic systems, designed to measure local electron temperature with high spatial and temporal resolution. One of these—a Fourier Transform Spectrometer—will be used in particular to measure the power loss from the ITER plasma due to ECE radiation and to study the non-thermal electrons in the plasma.   R&D and experimental activities are currently underway at a dedicated ITER India laboratory in Gandhinagar (western India). A prototype of the fast-scanning Fourier Transform Spectrometer (FTS), based on requirements specified by ITER India, was manufactured by Blue Sky Spectroscopy Inc., Canada. This prototype has been installed at the ITER India laboratory where post-installation acceptance tests have been carried out and found satisfactory.   Based on a polarizing Michelson interferometer (70-1000 GHz), this fast-scanning Fourier Transform Spectrometer also consists of a cryo-cooled, dual-channel Tera-Hertz radiation measurement detector system. Experiments will be carried out to test attenuation in transmission line components; the results obtained will be instrumental in providing input for the design of an ultra-wideband (70-1000 GHz) transmission line for the ITER ECE diagnostic system.

ITER's vacuum vessel port plugs are critical components that seal the plasma chamber and allow experiments to take place in a high vacuum environment. The Russian Domestic Agency—responsible for supplying four test stands for the vacuum, heat and functional testing of the port plugs before their installation on the machine—has contracted with the Russian firm Cryogenmash for the development of the technology. The team at Cryogenmash is currently testing the sealing flanges that will secure the port plugs on the test stand and running tests on the gaskets to arrive at a final choice of technology and material. Vacuum and leak tests were run recently with results that surpassed expectations. Watch a five-minute video of the work underway courtesy of ITER Russia.