The superconductors for the ITER magnet system are among the longest-lead production items for the project; the first five Procurement Arrangements concluded by the ITER Organization between late 2007 and mid-2008 concerned the conductors for the toroidal field magnet system.
The Russian Domestic Agency is responsible for 20 percent of toroidal field conductor procurement and 14 percent of poloidal field conductor procurement. Production is ongoing according to the schedule of the Procurement Arrangements.
On 25 June, the second batch of toroidal field conductor unit lengths started on their way from the premises of the Kurchatov Institute in Moscow to the city of La Spezia, Italy, where the winding of ten toroidal field coils will take place.
Demonstrating the attachment of Russian industry to fulfill its contractual obligations on time, two 415-metre production lengths of niobium-tin (Nb3Sn) conductor for toroidal field side double-pancakes were loaded onto trucks at the Institute. This latest shipment follows the delivery of four conductor unit lengths to Europe in October 2012, including a copper dummy and a 100-metre qualification length.
Seven similar units lengths have passed all of the tests stipulated in the Procurement Arrangement and meet ITER Organization requirements; they will, in turn, be shipped as well.
Ever since Dr Heike Kamerlingh Onnes walked the pace of superconductivity back in 1911, there have always been scientists endeavouring to exploit its tremendous properties through powerful; high magnetic field magnets.
These endeavours are turning into a reality at ITER, as the largest and most powerful superconductive magnets ever designed, with an individual stored energy of 2.2 Gigajoules (GJ), are being manufactured.
The Toroidal Field Coils is the ITER magnet system responsible for confining the plasma inside the Tokamak vacuum vessel, using Cable-In-Conduit niobium-tin-based conductor technology.
Procurement for the 19 Toroidal Field Coils (TFCs) is shared between the Japanese Domestic Agency (JA-DA), and the European Domestic Agency Fusion for Energy(EU-DA).
Following the last call for tender in August 2012, the first of a series of procurement contracts of the nine Japanese TF coils has been awarded to Mitsubishi Heavy Industry as a main contractor, with Mitsubishi Electric Corporation (MELCO), as a sub-contractor — a well-known stakeholder in superconducting magnet world.
_To_39_Tx_TF Coils are encased in large stainless steel structures. The nineteen encasing stainless steel coil structures (TFCS) procurement is the responsibility of the Japanese Domestic Agency (JA-DA) who recently placed two contracts respectively for First of Series European TFCS with Hyundai Heavy industry in Korea and for Japanese TFCS with Mitsubishi Heavy Industry in Japan.
With a total weight of 3400 tons, the „superstructure” of TF coils is pushing the limits of manufacturability. Millimetric tolerances require state-of-the-art welding techniques (plate thickness on 316LN is up to 180 mm) to reach high quality requirements. As a result it is necessary to use specialists in heavy industry.
From 1 to 3 October 2012, the Collaboration Toroidal Field Coil Working Group met in NAKA (Japan) after visiting Hyundai Heavy Industry, Mitsubishi Heavy Industry and MELCO manufacturing premises. This meeting was attended by TFC and TFCS Technical Responsible Officers (TROs) from the ITER Organization, the European Domestic Agency and JA-DA. Several specialists from JA-DA supplier Mitsubishi Heavy Industry were also invited to participate in the meeting.
Such meetings are essential for resolving common Toroidal Field Coil system issues between both DAs and their multiple suppliers, and to manage the interfaces and tolerances between the winding packs and the coil structures.
It goes without saying that regular contact with the Domestic Agencies industry, through meetings with TROs will guarantee the prompt solving of any issues that may arise within such a challenging production environment.
The manufacturing of the first series of double pancakes as part of first Winding packs by both DA is planned to start in September 2013, with delivery of the first winding pack in 2014 bringing up to full speed the.series production.
Given that the knowledge-based coil fabrication will be very dynamic, improving insight in those magnets tolerances will be essential as discussed with JA-DA TRO Norikiyo Koizumi and EU-DA TRO Alessandro Bonito Oliva.
Alexandro Bonito Oliva reported additionally on recent progress concerning the commissioning of the European TF winding tooling facility, the heat treatment oven and ongoing qualification tasks on joint, helium inlet and impregnation trials.
In spite of the difficulties of coordinating fabrication work with such a vast logistic and high production rate, the ITER Organization is confident in the ability of the DA suppliers and of the ITER TF IO-DA team project capacity to continue working in a cooperative and synergetic manner in order to reach our common goal.”
The TF Collaboration Meeting is also an opportunity to showcase the work done in the Japanese and European DAs. The substantial progress achieved by both European and Japanese domestic agencies would not have been possible without an effective collaboration with the TF team.
Having recently celebrated its fifth anniversary, the ITER Project has moved steadily from negotiations to real manufacturing, and from dummy testing to production of the tokamak’s construction elements.
One of the first systems to be manufactured in line with the ITER Organization (IO) Integrated Schedule Plan is the superconductor for the ITER magnet system. Russia has demonstrated high stability and reliability during this process, fulfilling all its obligations in time. This has not only been acknowledged by the IO experts, but also by the international superconductor community.
The Russian Toroidal Field (TF) conductor with bronze route strands was tested in the SULTAN facility by Centre de Recherches en Physique des Plasmas- Ecole Polytechnique Fédérale de Lausanne (CRPP-EPFL) in late September — early October 2012. This is the fourth Russian sample to be tested in SULTAN but the first sample containing two sections of conductor made of real production length which will be used to manufacture real TF coils for the machine. The left section of the conductor was cut from side Double Pancake pre-production conductor (Phase III) while the right section was made from first production (Phase IV) regular Double Pancake.
The results obtained with the the TFRF4 (Toroidal Field Russian Federation # 4) sample show very good agreement with results of the two last samples TFRF2 and TFRF3, which demonstrated the relatively good stability of the conductor during electromagnetic cycling, as well as its good durability during the warm-up/cool-down procedure.
Testing the TFRF4 sample was a very important milestone which completed the pre-production phase of the TF conductor procurement process. This means we can now proceed to the final production stage. At the same time, it opens the way to start shipping the real conductors to the coil manufacturer so they can be used to make coils for the ITER tokamak.
Manufacturing the toroidal field conductors for the ITER magnet system is a sophisticated, multistage process. Early this year, specialists at the All-Russian Cable Scientific Research and Development Institute (VNIIKP) in Podolsk, Russia twisted semiconductor strands into a 760-metre niobium-tin (Nb3Sn) cable—the second product of this kind manufactured in Russia.
At the end of February, at the High Energy Physics Institute in Protvino, this cable was pulled through a stainless steel jacket that had been assembled on site. The process involved the most advanced Russian technology and knowhow. The jacket itself—reaching nearly a kilometre in length and composed of more than 70 tubes welded together by gas tungsten-arc welding technology—was exposed to triple testing of the weld seams' quality and reliability.
During the next stage in the process, the jacketed cable, called a conductor, was compacted and spooled into a solenoid measuring four metres in diameter. Following vacuum and hydraulic tests at the Kurchatov Institute in Moscow, the conductor will be shipped to Europe.
Follow this link to a 10-minute video in English that will bring you inside the Russian factories involved with toroidal field conductor manufacturing for ITER.
Click here to see the video in Russian.
One of the greatest challenges to monitoring the production of the large and complex components at the heart of the ITER magnet system is the quick and efficient exchange of quality assurance/quality control (QA/QC) documents and data—important information that needs to be reviewed during the manufacturing process and cleared for acceptance by the responsible Domestic Agency and the ITER Organization.
Following the successful implementation of the Conductor Database tool that tracked production data for the ITER conductors at six Domestic Agencies and their suppliers right through to final acceptance tests, it was decided to develop and implement a Magnet Manufacturing Database (MMD) on the same model.
The Magnet Manufacturing Database will be the main tool for monitoring the QA/QC processes of the Procurement Arrangements for magnet coils, magnet structures and magnet feeders. This web-based application, integrated into ITER’s collaborative platform ICP, provides data and process integration with unified access and workflow. For the manufacturers, it offers an inventory control system with the possibility of integrating test result data and acceptance criteria functionalities, and of automatically generating barcodes and lot/serial numbers to facilitate tracking.
For the ITER Organization, the workflow management system included in the database matches the control points defined in each Procurement Arrangement and the manufacturing processes defined in the Manufacturing Inspection Plan. References to ITER documents are included for procedures, instructions, and specifications … allowing the ITER Organization to identify and manage critical operations such as welding.
The Magnet Manufacturing Database can manage any kind of complex manufacturing process chain, regardless of product type. Real-time production status and work-in progress monitoring will be also developed in a near future, using the IT online reporting system to extract and display data from the database in an efficient manner.
The success of such a tool will rely on the ability of its users around the world to input data in a timely manner. After a prototype implementation at the European Domestic Agency for the toroidal field coil winding packs, representatives of the ITER Magnet Division were in China mid-May to provide extensive training to the staff of the Chinese Domestic Agency, its supplier ASIPP, and some of the ASIPP sub-suppliers to launch the Magnet Manufacturing Database for the feeders, high temperature superconductor leads, and correction coils.