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.

2nd batch of Russian TF conductors en route to Italy


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.

Council welcomes progress in construction and manufacturing


The ITER Council met for the twelfth time in its history on June 19-20 in Tokyo, Japan.

The meeting brought together senior representatives from the seven ITER Members—China, the European Union, India, Japan, Korea, Russia and the United States—under the chairmanship of Hideyuki Takatsu (Japan).

The Council took note of the increasing pace of construction activities on the ITER site and progress in the manufacturing of components and supporting systems, highlighting the fact that major contracts have been placed recently and many leading industries are now involved in ITER construction.

During the 12th ITER Council, significant progress was reported in the manufacturing of ITER magnets: over 420 tons of niobium-tin strand (Nb3Sn) for the toroidal field conductors (90 percent of project needs) and 133 tons of niobium-titanium (NbTi) strand for the poloidal field conductors (51 percent of project needs) have been produced to date.

The Council reaffirmed the importance of sustained efforts regarding schedule implementation, while recognizing the challenges due to the first-of-a-kind nature of ITER. In this context, the governing body of ITER welcomed improved collaboration between the ITER Organization and the Domestic Agencies as part of the Unique ITER team.

Click here to view the photo gallery of the Twelfth ITER Council.
 
Read the Press Releases in
English and in French.

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.

STAC Chair reflects on latest meeting


The 14th meeting of the Science and Technology Advisory Committee (STAC) took place recently at the ITER Headquarters, from 14-16 May. We had the honour to be the first committee that met in the impressive Council Room after it was inaugurated by the ITER Council last November.

The STAC advises the ITER Council on two areas: the monitoring of ongoing project activity and the assessment of new proposals which imply a change in the ITER Baseline. The work at every meeting is based on the „STAC charges” adopted by the ITER Council. We assess the input from the ITER Organization that replies to recommendations made by the STAC and answers questions implied in the STAC charges.

The preparation of each STAC meeting involves an important work load on key ITER Organization staff and, as Chair of the STAC, I am aware that we must be careful with the amount of work that our requirements put on ITER Organization resources. I must also recognize the high overall quality of the reports and presentations delivered to our committee.
 
One of the first agenda points since I have participated in the STAC is the review of the project schedule from a technical point of view. Essentially, we analyze the technical causes of delays, including aspects which are midway between the technical and the managerial world such as configuration control, quality control, process control, etc.

As is happened in previous meetings, STAC 14 continued to express its concern about delays in the project. A number of systems are „critical or supercritical,” which means that they drive the First Plasma schedule, amongst them buildings, vacuum vessel, the poloidal field coils … and even the toroidal field coils could come into this category if delays are not stemmed. In addition, the „microschedule” reflected in the milestone achievement index and similar management parameters also indicates delays. However my personal perception, and to some extent that of many STAC members, is that the processes are improving and that the project schedule will soon consolidate. The STAC also acknowledged the organizational efforts and the implementation of recovery plans in order to mitigate the delays.

As I explained during the meeting with the staff in the afternoon of 16 May, my personal view on the delays is that they are not dangerous per se for the project but they undermine our credibility in front of stakeholders and society and this is the actual danger. In order to rebuild credibility our best tool is to keep working hard, as everyone involved is already doing. The ITER project is not only extremely complicated technically, it is also a nuclear project, which adds complexity. It was conceived with a complicated collaborative structure and, unfortunately, an underestimated allocation of resources. The fact that it is effectively progressing and that many components are actually being constructed should encourage all of us.

In addition to the technical analysis of the schedule STAC also looked at deferrals, i.e., procurements which are proposed to be delayed in order to free resources for other items that are needed in earlier phases of the project. We were worried about the deferred implementation of some systems, in particular diagnostics, and we have requested the ITER Organization to make every possible effort to implement those systems in time in order to avoid delays to the deuterium-tritium campaign derived from a slow implementation of the research plan.

During STAC-14 we noted that the organization and the progress of neutronics analysis has improved, for which we commended the ITER Organization. We have requested further detail on the results obtained for the next meeting of the STAC, in particular in relation to the heating of toroidal field coils and shutdown dose rates near the ports.

The news presented to the STAC on the central solenoid conductor was very good: in the last tests of a new cable developed by the Japanese Domestic Agency it showed very good stability—in fact, the degradation noted in earlier samples was essentially non-existing. Thus, we are now confident that the construction of the central solenoid can go ahead while keeping ITER’s performance as originally planned.

This STAC had the responsibility to make a clear recommendation on an important technical decision: whether or not to include in-vessel coils for ELM control in the Baseline. After we evaluated the specific problems that a lack of ELM control could cause, in particular when operating with a tungsten divertor, our unanimous recommendation was to include the coils in the ITER Baseline. STAC concluded that the potential benefits of the use of the coils in achieving ITER’s mission outweigh the risks, which were found to be very modest taking into account the solid design of the coils and the fact that they will be thoroughly tested during the non-nuclear phase.

STAC expects to make a recommendation next October for another key technical decision: the material for the first ITER divertor (tungsten or carbon).

At STAC-14 we analyzed the input from the ITER Organization regarding progress in divertor technology and tungsten divertor physics and the preliminary report prepared by the ITPA topical groups, which provided an excellent in-depth review of what is known today concerning tokamak operation with high Z* walls. The results from JET and other devices give a positive view of the operation with tungsten divertor in ITER but impose some scenario restrictions that must be further considered for ITER. Experiments to be carried out at JET in the near future, aiming at local melting of some tungsten elements of the divertor, will provide important input for a final recommendation by the STAC on its next meeting.

A final element in the last STAC meeting was the monitoring of progress in a number of areas: remote handling, quality control, ion cyclotron, and negative neutral beam heating. On this last item STAC looks forward with interest to the recent start of activities in the ELISE facility, which will provide important input to the physics and engineering design of the neutral beam injection sources for ITER.

In summary, STAC 14 corroborated important steps in the progress in the ITER project, which we expect to see reinforced next October thanks to the continued effort of all ITER Organization staff.

* A high Z element, like tungsten, is an element with a high
atomic number—its nucleus includes a large number of protons.

Let there be light!

Once the components of the ITER Tokamak are assembled and individually verified, a delicate and complex series of operations will be necessary before lighting the fire of First Plasma.

Commissioning, as this phase is called, means that all the different systems of the machine—vacuum, cryoplant, magnets—will be tested together in order to verify that the whole installation behaves as expected.

These commissioning operations all converge toward one point: the breakdown of the gas inside the vacuum vessel.

It happens in the following way: Initially, the toroidal field coils are electrically charged. Then the varying electrical current in the central solenoid and poloidal field coils generates an electric field around the torus of the tokamak causing the atoms in the gas to collide with the accelerated electrons. The gas in the vacuum vessel becomes ionized (electrons are stripped from the atoms) and reaches the state of plasma.

„At this moment,” explains Woong Chae Kim who joined ITER two months ago as Section Leader for Commissioning and Operations, „First Plasma will be achieved and the commissioning process will be over.”

ITER commissioning is expected to last more than two years and every step—from vacuum vessel leak-testing to the electrical charging of the magnets—will bring its own challenges. Woong Chae, however, is confident. „In the long history of tokamaks, start-up operations have never failed. Technically, I am not afraid. I’ve done it before …”

„Before” was five years ago, when Woong Chae was in charge of plasma commissioning at KSTAR. On 13 June 2008, following six months of commissioning operations, the large Korean tokamak (and the first to implement superconducting niobium-tin coils) achieved a First Plasma that surpassed the original target parameters.

From a technical perspective, commissioning KSTAR was close to what it will be at ITER. The difference lies in the regulatory status of the two devices—ITER is a nuclear installation, KSTAR is not—and in the inner workings of the organization.

„I participated in several design reviews for ITER components over the past four years and have had many opportunities to experience the complexity of the decision-making process within the ITER Organization. It is indeed a very complex machinery, even more than I had anticipated …”

KSTAR, which he joined in 1995 when the project was launched, taught something essential to Woong Chae: „While doing your own job on your own system or component, it is essential to have an overview of the whole device. If you don’t, coordination and interfacing becomes very, very difficult …”

Woong Chae chose to train as a fusion physicist/engineer because he felt fusion was „cool.” „It’s ideal as an energy-producing source, fascinating in terms of physics and technology and so different from the things one comes across in daily life.”

The first fusion device he encountered at graduate school in Seoul was the small tokamak SNUT-79 that Korea had developed in the late 1970s—the country’s first significant step onto the fusion stage. At the time, says Woong Chae, „the device was already a museum piece standing at the centre of the laboratory.” He then worked on the mirror machine HANBIT („Great Light”) in Daejeon, a partial reincarnation of the MIT’s 25-metre-long TARA, where he „learned how to manage big projects.”

After spending 18 years at KSTAR, Woong Chae felt that ITER was the „natural playground" for people like him—people who thrill at the challenge of „organizing men and procedures in order to make things happen.” Several ITER colleagues like Chief Engineer Joo Shik Bak or CODAC Section Leader Mikyung Park made a similar choice.

Woong Chae has moved to Aix-en-Provence with his wife, who spent a year in France as a graduate student, and their 16 year old son. They live near „Painters Ground” and have a beautiful view of Mount Sainte-Victoire. „Although I do not speak much French and am not what you would call a specialist in impressionism, I’m on familiar ground. In the early days of my marriage, we lived in Daejeon, close to restaurant named … Cézanne.”

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.

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.

Corrective actions in place to accelerate construction

Last Wednesday, ITER Director-General Osamu Motojima called for an all-hands meeting in the Headquarters’ brand-new amphitheatre in order to brief the ITER Organization staff on the outcome of the recent meetings of the projects scientific and managerial advisory committees. To this memorable event, Director-General Motojima had invited both the present and former chairmen of the Management Advisory Committee, Ranjay Sharan and Bob Iotti.

At the outset, the Director-General presented the conclusions of the 14th meeting of the project’s Management Advisory Committee (MAC) that had taken place on 29-31 October. The MAC had acknowledged the intensive work done by the ITER Organization in collaboration with the seven Domestic Agencies since the special MAC meeting held in August. Required schedule recovery actions have been taken and the collaboration between the ITER Organization and the Domestic Agencies has been intensified through the establishment of the Unique ITER Team.

„However, the MAC recognized that further and intensive efforts are necessary,” MAC Chair Ranjay Sharan explained. „The variances will have to be minimized by parallel working approaches and innovative methods. The MAC will closely monitor these approaches.”

„Yes, there are issues,” Iotti admitted, „but we are working closely together to resolve them.” Of great concern: the delays related to six super-critical items—the buildings, the vacuum vessel, the poloidal field coils, the toroidal field coils, the central solenoid conductor and the cryostat.

Two other essential issues were the focus of this 14th MAC meeting: the rules for further distribution of credits amongst the ITER Members as proposed in the „MAC-10 Guidelines,” and the proposal for a simplified assembly plan with the intention to recover some of the time slippages. „Based on the different feedback we received to this plan, the MAC suggests that the project remain focused on the normal step-by-step assembly strategy, but that it evaluate options to reduce risks and the time required for the assembly and the transport of components in order to provide more confidence in the dates for First Plasma and Deuterium-Tritium operation,” Sharan said.

As for the technical assessment, the Science and Technology Advisory Committee (STAC) commended the ITER Organization and the ITER Domestic Agencies on significant progress made, especially in the manufacturing of ITER magnets. More than 350 tons (73,000 km) of niobium-tin (Nb3Sn) strand for the toroidal field conductor have been produced so far, corresponding to approximately 75 percent of total amount needed. Also, approximately 65 tons of poloidal field conductor strand (25 percent of supply) have been produced.

The STAC noted that—with the exception of the poloidal field coils—there are currently no new major delays in the critical path due to magnets. The STAC further complimented the ITER Organization’s comprehensive report on remote handling and the good progress that has been made in developing a strategy for the installation, maintenance and potential repair of the first wall and the divertor.

„Take pride in what you have accomplished so far,” and, „Work in cooperation with others as team,” were the final comments from Bob Iotti and Ranjay Sharan respectively.



Corrective actions are now in place to accelerate ITER construction

Last Wednesday, ITER Director-General Osamu Motojima called for an all-hands meeting in the Headquarters’ brand-new amphitheatre in order to brief the ITER Organization staff on the outcome of the recent meetings of the projects scientific and managerial advisory committees. To this memorable event, Director-General Motojima had invited both the present and former chairmen of the Management Advisory Committee, Ranjay Sharan and Bob Iotti.

At the outset, the Director-General presented the conclusions of the 14th meeting of the project’s Management Advisory Committee (MAC) that had taken place on 29-31 October. The MAC had acknowledged the intensive work done by the ITER Organization in collaboration with the seven Domestic Agencies since the special MAC meeting held in August. Required schedule recovery actions have been taken and the collaboration between the ITER Organization and the Domestic Agencies has been intensified through the establishment of the Unique ITER Team.

„However, the MAC recognized that further and intensive efforts are necessary,” MAC Chair Ranjay Sharan explained. „The variances will have to be minimized by parallel working approaches and innovative methods. The MAC will closely monitor these approaches.”

„Yes, there are issues,” Iotti admitted, „but we are working closely together to resolve them.” Of great concern: the delays related to six super-critical items—the buildings, the vacuum vessel, the poloidal field coils, the toroidal field coils, the central solenoid conductor and the cryostat.

Two other essential issues were the focus of this 14th MAC meeting: the rules for further distribution of credits amongst the ITER Members as proposed in the „MAC-10 Guidelines,” and the proposal for a simplified assembly plan with the intention to recover some of the time slippages. „Based on the different feedback we received to this plan, the MAC suggests that the project remain focused on the normal step-by-step assembly strategy, but that it evaluate options to reduce risks and the time required for the assembly and the transport of components in order to provide more confidence in the dates for First Plasma and Deuterium-Tritium operation,” Sharan said.

As for the technical assessment, the Science and Technology Advisory Committee (STAC) commended the ITER Organization and the ITER Domestic Agencies on significant progress made, especially in the manufacturing of ITER magnets. More than 350 tons (73,000 km) of niobium-tin (Nb3Sn) strand for the toroidal field conductor have been produced so far, corresponding to approximately 75 percent of total amount needed. Also, approximately 65 tons of poloidal field conductor strand (25 percent of supply) have been produced.

The STAC noted that—with the exception of the poloidal field coils—there are currently no new major delays in the critical path due to magnets. The STAC further complimented the ITER Organization’s comprehensive report on remote handling and the good progress that has been made in developing a strategy for the installation, maintenance and potential repair of the first wall and the divertor.

„Take pride in what you have accomplished so far,” and, „Work in cooperation with others as team,” were the final comments from Bob Iotti and Ranjay Sharan respectively.



Russian TF conductor successfully tested in SULTAN

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.


ITER "conductor community" meets in Moscow

The traditional International Conductor meeting was held in Moscow on 10-13 September, 2012. The regular meeting was attended by representatives from the ITER Organization, experts from the ITER Domestic Agencies of Europe, China, Japan, Republic of Korea, Russia and USA, as well as specialists from the DAs’ suppliers.

Such meetings are particularly important since the ITER magnetic system, with conductors forming its core, is one of the ITER tokamak’s key elements. The manufactured conductors, which are designed to withstand super high current in continuous mode, have to meet the IO’s strict requirements.

At the moment, 10 out of the 11 conductor Procurement Agreements, are either well into the production phase or are completing the qualification/pre-production phase. This is particularly true for the Toroidal Field conductors, where 75 percent of the required Nb3Sn strands and one third of the cable-in-conduit conductor unit lengths have been completed. Also, a technical solution has been found for the Central Solenoid conductors that are being implemented by the ITER Japanese partner.

„This is a clear indication  that the ITER project is moving ahead and is able to keep schedule”, says the meeting’s Chair Arnaud Devred, ITER Superconductor Systems and Auxiliaries Section Leader.

In Devred’s opinion, „in spite of the difficulties of coordinating work with about 30 suppliers and six DAs around the world, the ITER conductor community has always tried to work in a cooperative and synergetic manner, and the conductor meetings have always been a great opportunity for sharing experience and tackling difficult interface issues.

The conductor meeting is also an opportunity to showcase the work done in the Russian Federation and for the DAs involved in coils procurement to visit the conductor production facility”. Russia is responsible for the procurement of 22 kilometres of conductors, destined for Toroidal field (TF) coils, and 11 kilometres destined for the Poloidal field (PF) coils of the ITER magnet system. TF coils include more than 90 tons of superconducting Nb3Sn strands; PF coils include 40 tons of Nb-Ti strands.

Arnaud Devred highly praised the progress achieved by the Russian suppliers saying that „The Russian Domestic Agency has now entered full TF conductor and PF cable production. It is a proactive partner, eager to play collectively and to assume its role within the ITER collaboration”.

The next regular meeting is planned for March 2013 in Cadarache.


Where conductors are born

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.


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.


F4E to study non-destructive testing technologies

Testing components in a rigorous manner and identifying possible improvements before assembling them is a fundamental step in a project as technologically complex as ITER. The need for leading expertise and knowledge transfer is high on the agenda.
In line with the above considerations, a framework contract has been signed between ITER’s European Domestic Agency Fusion for Energy (F4E) and TWI Ltd, the World Centre for Materials Joining Technology, for a maximum value of EUR 800,000 over a period of four years. TWI will provide F4E with know-how through engineering studies, assessments, technical audits and qualification procedures in the area of joining of components and non-destructive testing technologies.
The results will feed into the manufacturing processes of key structural components like the vacuum vessel and magnets, in-vessel components and the remote handling systems. In addition, modelling activities will be carried out in the areas of heat transfer, prediction of distortions and residual stresses. 

F4E has already identified that the first engineering activities will concern the vacuum vessel and the toroidal field coils. A task on friction coefficient testing is envisaged for the vacuum vessel, while the quality of the welding procedure will be assessed for the toroidal field coils.