Manufacturing milestone achieved in Europe

The first step in the fabrication of the full-size, superconducting prototype of a toroidal field coil double pancake has been successfully carried out in Europe. Winding was completed at the beginning of August at the ASG premises in La Spezia, Italy.

The European Domestic Agency, Fusion for Energy, is responsible for procuring ten toroidal field coils (and Japan, nine). These D-shaped coils will be operated with an electrical current of 68,000 amps in order to produce the magnetic field that confines and holds the plasma in place. Toroidal field coils will weigh approximately 300 tons, and measure 16.5 m in height and 9.5 m in width.

Each one of ITER’s toroidal field coils will contain seven double pancakes. These double pancakes are composed of a length of superconductor, which carries the electrical current, and a stainless steel D-shaped plate called a radial plate, which holds and mechanically supports the conductor through groves machined on both sides along a spiral trajectory.

The first stage of toroidal field coil manufacturing—the winding of the double pancakes—is the most challenging. It consists of bending the conductor length along a D-shaped double spiral trajectory. As the conductor must fit precisely inside the radial plate groove, it is vital to control its trajectory in the double pancake and in the groove of the radial plate with extremely high accuracy. The trajectory of the conductor, in particular, must be controlled with an accuracy as high as 0.01 percent.

For this reason, the winding line employs a numerically controlled bending unit as well as laser-based technology to measure the position and the dimensions of the conductor. The winding takes place in an environment with a controlled temperature of 20 °C +/-1 C, at an average speed of 5 m of conductor per hour.

For the European commitments to ITER, a consortium made up of ASG (Italy), Iberdrola (Spain) and Elytt (Spain) will manufacture the full-size, superconducting prototype as well as the production toroidal field coil double pancakes in the future.

The next steps in the manufacturing process are: heat-treatment of the double pancakes at 650 °C in a specially constructed inert atmosphere oven, electrical insulation; and finally the transfer of the double pancakes into the grooves of the stainless steel radial plates. After assembly and the application of electrical insulation on the outside of the radial plate, the module is finally impregnated with special radiation-resistant epoxy resin to form the prototype double pancake module.

Work on the module is scheduled to be completed by the beginning of next year, in time to allow for the prototype to be tested at -77 K in order to assess the effect of the low temperature. The module will then be cut in sections in order to analyze the impregnation of the insulation.

Read the detailed article on the F4E website here.

A visit to Mitsubishi’s Futami plant

Of the 19 toroidal field coils that will be produced for ITER (18 for Tokamak assembly, plus one spare), 9 will be procured by Japan.

The Japanese Domestic Agency has contracted with four major Japanese and Korean companies—Mitsubishi Heavy Industry, Japan (main contractor, coil case manufacturer #1); Mitsubishi Electric Corporation, Japan (winding pack manufacturer #1); Toshiba, Japan (winding pack manufacturer #2); and finally Hyundai Heavy Industry, Korea (coil case manufacturer #2 ).

Two weeks ago, participants to the Unique ITER Team (UIT) activities that followed the Twelfth ITER Council in Japan (19-20 June) had the opportunity to visit Mitsubishi Heavy Industry’s Futami facility near Kobe, where the first toroidal field coil will be wound and integrated.

Installation of the winding equipment at the Futami facility should be completed in September, allowing for dummy winding to proceed until the end of the year. Double pancake dummy winding should begin in early 2014.

The visit of the winding workshop and a discussion on the schedule presented by Mitsubishi Heavy Industry left the ITER guests with „a strong feeling of confidence,” says Head of IO-DA Coordination Songtao Wu.

Progress on magnet supports in China

The Chinese Domestic Agency is building the full set of magnet supports for ITER, representing more than 350 tons of equipment. The magnet supports will support the overall tokamak gravity load of 10,000 tons as well as withstand the unprecedented large electromagnetic loads experienced by the magnets.

The gravity support system, attached to the base of the cryostat with 18-fold symmetry (see image), needs to accommodate local thermal shrinkage during operation of -32 mm for the toroidal field coil structure cooled to 4K while remaining rigid against all out-of-plane bending.
In May, representatives of the ITER Organization and the Chinese Domestic Agency were present to witness a step forward in the preparation of a gravity support mockup test frame, which is part of the qualification phase of the Magnet Supports Procurement Arrangement.

The mockup aims to verify the reliability of design and simulate some sub-scale operation loads on the ITER gravity supports. To this aim, a true-size gravity support mockup and a multi-dimensional loading test frame system was designed by the Southwestern Institute of Physics (SWIP).

At the beginning of 2012, the loading frame system was fabricated by the Changchun Research Institute for Mechanical Science Co, Ltd. and pre-accepted by both the Chinese Domestic Agency and SWIP. It was delivered to SWIP in February for assembly.
In May 2103, the first set of Alloy 718 fasteners were released for the final gravity support mockup test installation; these had been manufactured by Guizhou Aerospace Xinli Casting & Forging Co., Ltd.

Wuhan Heavy Machinery, the main machining and welding supplier of the Chinese Domestic Agency, is currently producing prototypes of poloidal coil supports in order to optimize and qualify final manufacturing processes in the prospect of beginning series manufacturing in 2014.

China delivers first load to ITER

It’s a long road from the Institute of Plasma Physics (ASIPP) in Hefei, China to the ITER site in southern France: 500 kilometres by route to the port of Shanghai; some 10,000 nautical miles from Shanghai to the port of Marseille-Fos; another hundred kilometres for the last leg of the journey, from Fos to the ITER site.

The distance was covered by trucks and the container ship Lyra in 38 days. Three crates that had been loaded at Hefei on 25 April were delivered to the Poloidal Field Coils Winding Building on Monday 2 June, three days ahead of schedule.

The crates contained the first batch of ITER items delivered by ITER China to the European Domestic Agency Fusion for Energy (F4E): 737 metres of dummy conductor, in three lengths, to be tested in a mockup of poloidal field coil number five (PF5). The 25-ton load was also the first ITER item to enter the large on-site winding facility.

„The conductor will be used to test the whole fabrication process,” explained Neil Mitchell, head of the ITER Magnets Division, as the crates were being unloaded and inspected. „This copper conductor will be wound, tested for tolerance, insulated, impregnated under vacuum and formed into a 'double pancake' in the same way the actual superconducting niobium-titanium conductor will be handled by F4E at a later stage. What matters here are the mechanical properties, which are similar in both the copper dummy and the actual superconductor.”

An ITER load, even when it’s only a dummy component destined for mockup testing, is not an ordinary load. The transport crates were equipped with several monitoring devices to record movement and accelerations throughout the journey; other systems monitored the pressure inside the conductors, which are filled with pressurized inert gas, to confirm that there was no contamination by damp or salt.

Verifying that the crates (and hence the conductors) had not suffered during the 38-day voyage was the first thing that Piergiorgio Aprili, from F4E, and Chen Huan and Sun Yana, representing the Chinese transporter Sinatrans, did upon the delivery of the load. The integrity of the accelerometers was verified—proof that no major shock had occurred—and the crates' „Black Box” was recovered for later analysis.

Compared with the oversized components that will soon be delivered to ITER this week’s 25-ton load appeared quite modest. However, for all those involved—ITER China, Sinatrans, F4E, the ITER Organization and the logistics service provider Daher—this was an important moment. „We have already managed several shipments of small components to and from the ITER Domestic Agencies,” explained Daher’s Laurence Prudhomme who oversaw the unloading operations, „but this is the first real heavy load we’re dealing with.”

Beginning early next year, the loads will change in scale: several hundred tons, by then, will be routine.

View an example of accelerometre data collected during the transportation of TF Coil conductor from Hefei to the Japanese port of Kobe in November 2012.

First hardware afloat from China

On Thursday 25 April, the morning silence at the Institute of Plasma Physics (ASIPP) in Hefei, China, was broken by the noise of a high powered trailer. Inside the superconductor shop of ASIPP, workers were busy preparing to load the 737 metres of dummy conductor for ITER’s Poloidal Field Coil number five (PF5)—this represents the first delivery from China to the ITER construction site in France.
According to the Procurement Arrangement signed between the Chinese Domestic Agency and the ITER Organization, China will fabricate 64 conductors for ITER’s poloidal field coils, including four dummy conductors for cabling and coil manufacturing process qualification. ASIPP is responsible for all the poloidal field conductor fabrication in China. The fabrication of the PF5 dummy was completed in by ASIPP in 2011.
„This is the very first batch of ITER items to be shipped from China to the ITER site in Cadarache," said Luo Delong, Deputy Director-General of ITER China. Before, conductors for the toroidal field coils had been shipped to Japan and Europe. "This milestone is a further step for the ITER project. According to our schedule, we will now start massive production of conductors this year. Our goal is that all procurement items from China be supplied consistent with the ITER schedule and with ITER quality requirements.”

According to the shipment schedule the PF5 dummy conductors, which left Shanghai on 30 April, will arrive at the ITER site on 5 June.

Team work celebrated at last Conductors Meeting

In pre-ITER times, the world production of niobium-tin (Nb3Sn) strands did not exceed 15 tons per year. Discovered in 1954, this intermetallic compound that exhibits a critical temperature of ~18 K and is able to withstand intense magnetic fields was used mainly in high field coils and nuclear magnetic resonance equipment.

To match the needs of ITER’s 19 toroidal field coils (18 plus one spare), the world production capacity of Nb3Sn strand had to be ramped up by one order of magnitude. As of today, 400 tons of Nb3Sn have been produced by the industry of the six ITER Domestic Agencies involved in conductor procurement, representing 85 percent of toroidal field coil needs.

Nb3Sn conductors will also form the core of the central solenoid, the backbone of the ITER magnet system. Strand production has been launched in Japan for the lower module (CS3L) and conductor lengths will be shipped at a later time to the US where the central solenoid will be manufactured.

For ITER’s third major magnet system—the poloidal field coils—because the magnetic field they produce is less intense, they can be manufactured from the metallic alloy niobium-titanium (NbTi), which is cheaper and easier to produce than the brittle Nb3Sn.

The Russian-European collaboration that procures NbTi strands for ITER has already produced 80 tons of Strand 1, destined for poloidal field 1 and 6. China, responsible for the procurement of conductors for poloidal field coils 2 to 5, has registered nearly 50 tons of of NbTi Strand 2 into the Conductor Database (this essential tool monitors the strand, cable, jacket and conductor production of each Domestic Agency). China will send its first poloidal field conductor shipment to the ITER site within the next two months.

Altogether, conductors for the magnet systems account for 13 percent of the total ITER project credits.

_To_45_Tx_These figures and other information relating to correction coils, feeder conductors, manufacturing issues, quality control, test results and technical issues were presented and discussed at last week’s meeting on conductor production status at the Château de Cadarache.

The Conductor Meeting, which has been held twice a year since 2008 (at ITER in the spring and in one of the „Conductor Domestic Agencies” in the fall), gathers representatives of the ITER Organization, the Domestic Agencies and their suppliers.

„It is an opportunity to share and benefit from each other’s experience,” says ITER Superconductor Systems and Auxiliaries Section Leader Arnaud Devred who traditionally chairs the meeting. „As all conductors are now in the production phase, the feeling in our community is definitely optimistic. Everything is moving ahead and the collaborative spirit, not only between the ITER Organization and the Domestic Agencies but between the Domestic Agencies themselves, is truly excellent.”

Fusion, with a touch of science fiction

An imposing object stands at the heart of the Tom Hunt Energy Hall in the recently opened Perot Museum of Nature and Science in Dallas, Texas.

The four-metre-high structure is a mock-up of the ITER Tokamak—or, rather, a designer’s „interpretation” of the science of fusion and of the flagship device of fusion research.

Those familiar with the arrangement of components that make up an actual tokamak—central solenoid, vacuum vessel, toroidal and poloidal field coils, divertor, piping and feeders—will be a bit lost when gazing upon the towering mockup.

This is intentional. „Our goal was to create a sense of wonder in our visitors that might inspire them to learn more about the subject,” explains Paul Bernhard, whose team designed and installed the 700-square-metre Tom Hunt Energy Hall. „We see our tokamak as based in science, but coloured by a future vision influenced by science fiction—a somewhat cinematic element that you might imagine seeing in a new Star Trek film…”

The result is indeed spectacular. Although Bernhard’s tokamak looks a bit like a thermonuclear mushroom cloud—a „purely coincidental” similarity due to the geometry of the large rounded shape containing the brightly glowing "plasma" suspended over the narrower central core—it is a truly astonishing work of science art.

The moment of awe passed, visitors can experiment with a neon/argon plasma, manipulating it with a magnet; have a hands-on experience with actual toroidal field coil and central solenoid conductor sections provided by the US Domestic Agency; or watch video clips.

Impressed by the „amazing potential of fusion energy,” Bernhard and his team sought to „pass along [their] sense of inspiration.” In stimulating curiosity and enthusiasm for the sciences, a bit of artistic license can’t do any harm.

12 minutes to understand TF coil manufacturing

The magnets responsible for confining the ITER plasma—the eighteen D-shaped toroidal field coils—will form an impressive superstructure within the ITER machine: at approximately 6,000 tons (coils plus cases), they will represent over one-fourth of the Tokamak’s total weight.

In two new videos produced by the European Domestic Agency, we are taken inside a vast manufacturing facility in La Spezia, Italy, where preparations are under way for the fabrication of ten toroidal field coils (nine plus one spare) that are part of the European contribution to ITER.

From winding through heat treatment and on to insertion into radial plates, the toroidal field coil manufacturing process is complex and exacting, requiring unprecedented levels of tolerances and performances. In the videos, experts from the ASG consortium* and Europe speak of the technical challenges, the specialized tooling, and the qualification work underway.

You can see the two 6-minute videos on F4E’s website.

*ASG consortium: Iberdrola Ingeniería y Construcción SAU, ASG Superconductors SpA and Elytt Energy SL

Toroidal Field coils manufacturing gains momentum

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.

An eagerly anticipated dummy

After driving through the night, the oversize truck pulls up in the early May dawn at the ASG facilities in La Spezia, Italy. The special delivery, a wooden square box with 5-metre dimensions, contains a large spool around which the eagerly anticipated dummy of a 760 m long copper conductor is wound.

The dummy is a mockup of the ITER conductors. These conductors will each be used in the toroidal field coils to carry 68,000 amps of electrical current in order to produce the magnetic field which confines and holds the plasma in place. In total, 19 superconducting conductor lengths (each measuring 760 m) and 8 conductors (each measuring 415 m) will be produced.

Although the final components will consist of superconducting materials, the dummy is made only of copper strands which have been plaited together (cabled) and inserted into a jacket in order to form a round conductor with a diameter of 44 mm. Nonetheless, the dummy package weighs an impressive 13 tons. Because of its large dimensions, it is only transportable during certain hours of the night after other traffic has been cleared.

The dummy was manufactured for the European Domestic Agency F4E by ICAS, an Italian consortium consisting of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Criotec, and Tratos Cavi. The next steps of the process will be undertaken by ASG, part of the Iberdrola consortium (which includes Iberdrola and Elytt), F4E’s toroidal field coil supplier and the company to which the dummy was delivered. The copper dummy length will be used for the commissioning of the toroidal field coil winding line.

In recent months, two additional toroidal field lengths made from superconducting strand were manufactured, thus completing the qualification phase during which both tooling and manufacturing procedures are verified. These conductor lengths are expected to be shipped to La Spezia by the end of the summer.

On May 15, the fabrication of the first production toroidal field conductor length was completed at Criotec: this length is the first conductor which will be inserted into the ITER machine. In the coming two years, 26 additional toroidal field lengths will be fabricated and supplied by ICAS.

Japanese artist creates stunning Lego Tokamak

Forget about tungsten, beryllium, niobium-tin and other exotic materials—the new trend in tokamak design these days is plastic.
The learned public was introduced to this new concept in the June issue of Scientific American. The US monthly’s four-page article titled „Fusion’s missing pieces” was illustrated with a stunning cutaway of a partially completed ITER Tokamak made of … Lego bricks.

All parts were in place, clearly visible and perfectly rendered in spite of the limitations of the Lego bricks' sharp edges: a D-shaped toroidal field coil suspended from a crane, the central solenoid, sections of the vacuum vessel, blanket modules, the divertor, feeders …

This 8,000-piece ITER mockup was both a technical achievement and a piece of art. It is the work of Japanese Lego bricks artist Sachiko Akinaga, who began playing with Legos at age 5 and later developed her hobby into an artistic quest.

„As a little girl in Tokyo,” she says, „I would never tire playing with Legos. It gave me a lot of confidence and joy. I could not believe I could create objects that I had first pictured in my mind …”

A graduate of the Toyo Institute of Art and Design in Tokyo, Sachiko has come a long way from what she considers her first work of Lego art: a box of tissues decorated with Indians dancing around a signal fire, a pond, and a crocodile that she created in 2002.

Over the years her work has evolved into a more and more sophisticated form of expression, culminating with her now-famous Let’s go to the Earth Park!”—an impressive project made with about 40,000 Lego bricks.

Last year, when the The New York Times decided to illustrate its winter travel issue with a logo made of Legos, representatives at the Lego Group led the newspaper’s editors to Sachiko.

Although it included only 15,000 blocks, the Lego structure was four times larger than her „Earth Park.” The artist confided to The New York Times that she worked for eleven days on the logo, including „many days nonstop, in 16-hour shifts”…

The iconic „T” logo (in gothic font) appealed to Sachiko for what she calls a „secret reason”: it also stands for the word tanoshi, which means „fun” in Japanese.

The New York Times cover caught the eye of several art directors and magazine editors in the US, among them those at Scientific American.

„Editors there gave me a cutaway view of the ITER Tokamak and a link to the ITER website. Needless to say, I knew absolutely nothing about fusion energy. Understanding the structure of a tokamak was very difficult. Basically, I used five images from the ITER web site.”

As with every Lego creation, the hardest part in building the ITER model was to make the rounded shapes—and there are many in a tokamak. Overcoming this difficulty owes as much to Sachiko’s technique as to inner workings of the viewer’s brain. „Legos create what is very close to a pixelated effect that the human eye and brain smooth out,” explains the artist. „When you look at an angled sphere made with bricks, your brain makes it appear round. I find this mental process very exciting …”

Sachiko’s rendition of the ITER Tokamak is both realistic and naïve, as a Lego construction should be. There are workers pushing a trolley loaded with pipes; others signalling to a crane operator with both hands as the delicate operation of installing a toroidal field coil is proceeding.

Of course, it won’t happen exactly this way during the assembly of the machine. Like all artists, Lego artists are entitled to some poetic license.

Five years into the ITER project

On 19 June, it will be five years since the Russian Domestic Agency officially opened its offices in the Kurchatov Institute in Moscow. Marking this fifth anniversary, a press conference was organized (*) within the premises of the Russian press agency RIA Novosti. The more than 25 participants from television, radio and newspapers demonstrates the level of interest in Russia in the ITER project.

The volume of Russia’s annual contributions to ITER has reached EUR 150 million. This year we signed 78 contracts for the execution of works and supply of equipment.

Russia’s participation in this project is giving the opportunity to the industries in our country to develop specialized technology and new manufacturing processes. In the city of Glazov, some 1,000 km east of Moscow, a whole new plant was built for the production of ITER’s superconductors. A cabling facility has been built in Podolsk and a jacketing factory in Protvino. At the Efremov Institute in St. Petersburg a High Heat Flux Facility was created, as well as the manufacturing lines for the first wall, divertor and poloidal field coil 1. The cryogenic engineering company JSC Cryogenmash, located in Balashikha near Moscow, is in charge of the design and construction of ITER’s Port Plug Test Facility Stands. The Institute of Applied Physics in Nizhniy Novgorod has manufactured the prototype of the ITER gyrotron, which it successfully tested at the Kurchatov Institute at the required 1MW of power during 1000 seconds.

In total, about 30 Russian companies are currently under contract with the ITER Project Center, as we call ourselves now—a private institution of the state-owned company Rosatom. And each of these contracts "pulls along" a whole chain of contractors and subcontractors …

The ITER project, besides its role as the ultimate experiment on the way to a new and benign energy source, to us also means new jobs and training, and the transfer of skills to young professionals. And we all know: education is the key!!!
Down the road, some of our experts will work on the installation itself. Until then, but we will continue to make use of the possibility of sending young engineers and scientists to the ITER Headquarters in France for a few months to allow them to get some hands-on experience. In a first experience of this kind, seven researchers recently had the chance to explore the ITER world and we will certainly take more advantage of this excellent opportunity in the near future.  

There has also been a personnel change in the Russian Council delegation to the ITER Council: Rosatom Deputy Director-General Vyacheslav Pershukov has been appointed by Prime Minister Vladimir Putin to represent the Russian Federation at the next meeting talking place in Washington, 20-21 June.

(*)The participants to the press conference were (from left) Andrei Reznichenco, RIA Novosti correspondent and moderator; Vasily Utkin, head of the Department of the Government Executive Office; Sergey Mazurenko, Deputy Minister for Education and Science of the Russian Federation and member of the delegation to the ITER Council; Evgeny Velikhov, president of NRC Kurchatov Institute, Academician of RAS and Council member; Vyacheslav Pershukov, Deputy Director General-Director of „Rosatom” and Council member; and, finally, Anatoly Krasilnikov, director of the ITER Project Center.