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Cryostat | Lower cylinder revealed

ma, 18/03/2019 - 18:16

They were all there: those who designed it, those who forged it, those who assembled and welded it, and those who closely monitored the requirements and procedures connected with a "safety important" component. Two years after an array of segments were delivered to ITER, the cryostat lower cylinder—one of the four sections that form the giant thermos that will enclose the machine — had been fully assembled. With scaffolding removed and just a thin translucent film to protect it, the massive structure was at last revealed, both delicate and mighty.
"This is the largest component that will go into the machine assembly pit," said Patrick Petit, ITER In-Cryostat Assembly Section leader. "It is also an example of broad and exemplary collaboration."
Like the other sections of the cryostat, the realization of the lower cylinder epitomizes the larger collaborative nature of ITER: designed by the ITER Organization, forged in India, it was assembled and welded by a German company under contract to India on international territory conceded by France.
"The realization of this component was not a single person's job," said Anil Bhardwaj, ITER Cryostat Group leader. "It has been quite a serious task for all of us, with a large variety of challenges, particularly regarding fitment and welding quality" added Vikas Dube, a mechanical engineer in his team, "and although there were lots of lessons learned, we will face them again when we commence the assembly and welding of the upper cylinder in the coming months."
Read more about the fabrication of the ITER cryostat here.

Divertor cassette bodies | Four years from prototypes to series

ma, 11/03/2019 - 17:21


Hell is a balmy place when compared to the environment of a divertor cassette body. In the vicinity of this ITER component, heat loads will be comparable to those at the surface of the Sun, and radiation will be almost as intense as in the neighbourhood of a neutron star. Cassette bodies will also have to resist the huge mechanical forces that will be exerted for a few tens of milliseconds in the event of a severe plasma disruption. Rarely—even in the space or nuclear industries—has a component posed so many fabrication challenges.
From its strategic position at the bottom of the vacuum vessel, the ITER divertor is the component that will extract the heat and the helium ash from the burning plasma. The divertor is made up of 54 individual "cassette assemblies" arranged in a circle—each one formed from a structural backbone (the cassette body), actively cooled plasma-facing elements (the "targets" and the "dome"), and diagnostic systems.
Cassette bodies are massive and contorted structures that weigh close to 5 tonnes. Prototype manufacturing began in 2013 under two contracts awarded by the European Domestic Agency, Fusion for Energy; five years later the Italian company Walter Tosto and the Italian-French consortium CNIM-SIMIC had each finalized a real-size, fully functional prototype, opening the way for series production to begin.
Under fabrication contracts signed in November last year with Fusion for Energy for the first 19 divertor cassette bodies, Walter Tosto will manufacture 15 cassette bodies and CNIM-SIMIC another 4—all for delivery by 2024. The order for the remaining 39 cassettes (including 4 spares) will be awarded at a later stage, as the divertor is not needed for the initial stages of ITER operation.
"Going from prototype to series manufacturing is a highly symbolic and rather moving moment for us," says Frédéric Escourbiac, ITER Divertor Section leader. "It is the culmination of seven years of hard work on detailed design development and on the demonstration of manufacturing feasibility. These actions were particularly demanding in terms of collaborative efforts with Fusion for Energy and their industrial partners."
"Series," however, does not mean "uniform": the 19 cassette bodies in the first production batch are of the "standard" type. The remaining 39 will present some added complexity, such as specific cooling for diagnostic systems or operational instrumentation, or specialized "cut-outs" for open lines of sight for neutron cameras.
"At ITER, we are used to dealing with systems that do not fit in the typical categories of industrial equipment," explains Laurent Ferrand, the ITER Technical Responsible Officer for the cassette bodies Procurement Arrangement. "When you first look at the technical specifications, what you see is a massive, complex stainless steel structure with lots of welds and very stringent welding and inspection requirements. But of course, it's much more than that ..."
Tolerances on the cassette bodies are sub-millimetric, which is quite standard for ITER but a huge challenge for such a massive component with moving parts. Leak-tightness is an even bigger challenge: "The prototypes were leak-tested at dedicated satellite facilities in Cannes, France, and Pisa, Italy. The engineers there were quite impressed by the 'ITER leak-tight' requirements—our criteria for a component like a cassette body are several orders of magnitude tighter than those for a satellite's fuel tank, for example."
Despite these considerable constraints and difficulties, Walter Tosto and CNIM-SIMIC took up the challenge, worked their way faultlessly through the prototyping phase, and produced fully functional components. The (numerous) lessons learned will be of great value for the series manufacturing phase.
Plasma-facing components and auxiliary systems will eventually be attached to the cassette body to form an 8-tonne cassette assembly that will be positioned within tenth-of-millimetre tolerances in order to be perfectly aligned with the machine's magnetic axis.
As minute variances during the manufacturing process and assembly of the vacuum vessel are inevitable, the positioning of the cassette assemblies, and hence of the whole divertor, will need to "recover" these slight departures from nominal dimensions and positions—a feat that will be achieved by custom machining the rail sections to which the cassette assemblies will be attached as well as all the interfacing elements between the divertor and the vacuum vessel structure.

HTS current leads | China launches series production

ma, 04/03/2019 - 18:52


Because they reduce the input power requirement for plant operation, high-temperature superconducting (HTS) current leads are one of the enabling technologies (together with superconducting magnets) for large-scale fusion power plants. First driven by the high-energy physics accelerator community, the development of high-current HTS leads is now being pushed by magnetic confinement fusion towards larger currents. At 68 kA, the ITER toroidal-field type HTS current leads will be the largest ever operated.
HTS current leads are key components of the ITER magnet system, transferring the large currents from room-temperature power supplies to very low-temperature superconducting coils at a minimal heat load to the cryogenic system. Although HTS current leads represent an additional cost over conventional current leads, this additional cost is quickly amortized due to savings in cryoplant operation.
ITER's largest magnets—18 toroidal  field coils, 6 central solenoid modules, 6 poloidal field coils, and 18 correction coils—will be supplied with 60 current leads, ranging from very large (68 kA for the toroidal-field type) to medium (10 kA for the correction-coil type), transferring up to 2.6 MA into and out of the cryogenic environment of the machine. Located at the far end of the magnet feeder relative to the machine (see diagram below) the current leads operate in much lower magnetic field than the magnet coils themselves.
The largest toroidal-field type of current lead is over 3 metres long and weighs 600 kgs.
The HTS current leads for the ITER Tokamak are procured by the Chinese Domestic Agency through the Institute of Plasma Physics (ASIPP) in Hefei. The Procurement Arrangement signed between the ITER Organization and the Chinese Domestic Agency for magnet feeders laid out a multi-year plan to develop the designs and to qualify the HTS lead manufacturing technology in ASIPP and its sub-suppliers Juneng and Keye.
Following the development of critical manufacturing technologies through targeted trials in mockups, Chinese contractors recorded a string of qualification milestones¹:
  • The successful testing of a pair of correction coil 10 kA current lead prototypes in March 2015;
  • The successful testing of a pair of toroidal-field type 68 kA current lead prototypes in July 2015;
  • The successful testing of a pair of poloidal-field/central-solenoid type current leads in 2016;
  • The completion of a Manufacturing Readiness Review in August 2016 (marking the end of the qualification phase).
Series manufacturing is now underway, and the first-of-series for all three types of HTS lead have been completed (see gallery). The fact that manufacturing is proceeding strongly, with only a small number of non-conformities, is a tribute to the thorough qualification efforts as well as the Chinese manufacturers' high level of expertise.

It should also be noted that the Chinese Domestic Agency and the ITER Organization put a supervision framework into place allowing local inspectors to witness critical manufacturing steps. Erwu Niu of the ITER China office now manages at least two inspectors who are permanently stationed at the suppliers' sites in Hefei.

Thousands of documents have already been uploaded to the ITER Organization Manufacturing Database—from material certificates, to personnel certificates and test reports. Documents attesting to the components' performance during testing—for example the final factory acceptance cold test in near-to operational conditions under full current—can be fully verified through the database before the final ITER Organization hold point is released.

At ASIPP, lead engineers Quan Han and Qingxiang Ran are now turning their attention to ramping up the pace of production to meet the ITER schedule. A number of additional pieces of large-scale manufacturing equipment—such as another electron-beam welding machine, insulation curing autoclaves and a third cold test station—are being commissioned to handle the extra load.

This year and next, up to 20 current lead pairs will be manufactured in parallel in by Juneng and Keye for shipment to ITER.

¹The qualification of the HTS current leads in China is summarized in an ITER Technical Report (Reference: ITR-18-001). You can download it on this page.

Vacuum leaks | A whole suite of tools and technologies

ma, 25/02/2019 - 21:24



The Greek philosopher Aristotle (384-322 BC) knew nothing about tokamaks. But when he stated in his famous aphorism that "Nature abhors a vacuum,"¹ he anticipated one of the problems that tokamak designers would face 25 centuries later.
Vacuum occupies a large part of ITER, both literally and figuratively—vacuum volumes are huge and vacuum challenges daunting. Successful plasma operation rests on the quality of the vacuum in the (aptly named) vacuum vessel, but also in the cryostat, the neutral beam injection system, and many other systems.
A vessel under vacuum is submitted to pressure from the external environment ... and the higher the vacuum, the more aggressive is the attack of particles from the environment and surfaces.
Gases and liquids will find the tiniest breach in a structure under vacuum. "A crack the width of a human hair is enough to alter the vacuum quality and halt fusion performance," emphasizes ITER Vacuum Section Leader Robert Pearce. Nature not only abhors a vacuum, it conspires by all available means to destroy it ...
Close to ten years ago, an intense R&D program was started to develop risk-mitigating concepts for leak detection and localization. The Procurement Arrangement that was recently signed between the European Domestic Agency, Fusion for Energy, and the ITER Organization is a direct outcome of this decade-long effort.
Under this agreement, Fusion for Energy will deliver a whole suite of ITER-designed systems and instruments to detect and localize leaks throughout the vast volumes of the vacuum vessel and cryostat, and also in smaller areas such as the neutral beam injectors or the cryopumping systems.
"Basically it's about ensuring the integrity and leak testing the totality of the machine: the 2,000 m³ of the vacuum vessel, the 8,500 m³ cryostat (pumping volumes);  the primary vacuum for the neutral beam, not to mention the tens of kilometres of piping carrying gases and fluids that could leak into these volumes," explains ITER Vacuum Section leader Robert Pearce.
Although the risk of leakage is minimized by design as well as best practices and quality control throughout the fabrication and assembly processes, it cannot be reduced to nil. "There should be no leaks," says Vacuum team member Liam Worth, "but experience tells us that if we achieve this it will be a 'miracle.' To date, all tokamaks, stellarators, particle accelerators, and other vacuum installations of large size and complexity have experienced a certain number of leaks."
Some leaks are "tolerable" but others are not. "There are thresholds," explains Liam. "We can cope with the thermal shield or magnet system leaking a minute quantity of helium into the cryostat. But a leak into the vacuum vessel, whether of air or water, starts to affect plasma performance as the size increases and so cannot be easily tolerated."
Once detected and localized, leaks can of course be fixed, generally by cutting, replacing, bypassing, or isolating the faulty part. In some cases it is relatively easy; in others—for example in the case of a leak occurring in one of the in-cryostat helium lines—it would be a "huge job" to repair, according to Liam.
Among the systems and tools to be procured by Fusion for Energy under the recent Procurement Arrangement is a spectacular device—a self-propelled "in-pipe inspection tool" that can wiggle its way into the smallest and most contorted piping networks (see video) and find its way deep into the cryostat.
Conceptualized by the ITER Organization and developed by Doosan Babcock in Scotland, the working prototype of the articulated tool can propel itself inside pipes no larger than 40 millimetres in diameter, move forward and backward, take a 90-degree turn and, thanks to a tiny video camera and built-in lighting system, provide high-resolution images (better than 0.01 mm) of potential cracks or faulty welds. The device, which is evocative of an ultraminiaturized freight train or an oversized, segmented tapeworm, is equipped with inflatable "bladders" that can isolate and locate leaks in precise sections.
Although basic in-pipe inspection tools are standard in industry for much larger pipes, the articulated tool is unique. "Nothing in the world can do what it does," says Liam. "It's reduced size means, for instance, that 100 percent of the thermal shield manifolds² are accessible for inspection and leak localization."
"With the exception of the drive mechanism, all the prototype tool's components, including motors, are off-the-shelf or slightly modified off-the-shelf," says Liam. "The concept design has been demonstrated but the tool can be significantly improved with the use of bespoke components that are smaller and lighter." This task of improvement will now pass to Fusion for Energy as part of the Procurement Arrangement.
"In the more distant future, with advances in material and electronic technologies, such a tool could be further miniaturized by a factor of 10 and provide an even more powerful tool for leak localization and repair for fusion devices and many others," concludes Pearce.
Achieving and maintaining the required vacuum in the ITER machine is an immense task that the Vacuum Team took on more than one decade ago. As ITER is now gearing up for assembly operations, the team is moving forward with a new set of tools and technologies that potentially enable the localization and detection of leaks smaller than the width of hair divided by one million.
¹-Aristotle couldn't have known that at the atomic scale, Nature—that is, the material world—is essentially made of ... vacuum.
²-A manifold is an arrangement of interconnected pipes. In the ITER thermal shield, the manifolds supply cryogens to the shield's panels.
Read a related story on the Fusion for Energy website.

On site | Drone survey on a perfect day

ma, 18/02/2019 - 18:15

There are days in winter when the skies over Provence are perfectly transparent. Snowy peaks 200 kilometres away appear close enough to be touched and farms, country roads and villages are all revealed in sharp detail.
A drone flying over the ITER site on such days captures every single iron bar, scaffolding tower, or embedded plate in the Tokamak Complex; every insulator in the electrical switchyard; and every component carefully wrapped in green plastic in the site's storage areas.
This new harvest of images from early February also reveals the broader setting of the ITER Project, among the rolling hills and plowed fields along the Durance River valley—a futuristic enclave in an unchanging environment.


Steady at the helm | Bernard Bigot accepts a second term

ma, 28/01/2019 - 18:04


In a unanimous decision, the ITER Council has voted to reappoint Dr Bernard Bigot to a second five-year term as Director-General of the ITER Organization. The Council decision centred on two factors: the strong performance of the project in recent years under Dr Bigot's leadership, and the complex challenges that lie ahead as construction completes, massive tokamak components arrive onsite, and the stringent, carefully sequenced assembly and installation schedule kicks off in 2020.
Stakeholders internal and external have welcomed the announcement as a signal from both the Council and Bigot himself of the intent to ensure reliability and continuity for the demanding days that lie ahead.
In 2013, two years before Dr Bigot took the helm of the ITER Project, a report from the biennial Management Assessment had issued a warning: change course or risk project failure. By March 2015, the project was clearly at risk. The staggering complexity of the machine itself—compounded by the intricate international Procurement Arrangements under which companies on three continents would fabricate ITER's first-of-a-kind components—was taking its toll.
The rigour with which the new Director-General set about organizational reform showed that he understood both the high stakes involved and the structural changes needed. The central dilemma was daunting: how to ramp up the pace of construction and manufacturing at the same time as the project was undergoing exhaustive internal and external reviews of ITER's design, engineering, schedule, and cost—and all the while driving a revolution in project culture.
The results have been significant. Physical progress on every front has been matched by renewed optimism across the project. Once-sceptical stakeholders have been reassured. The project recently reached 60% completion through First Plasma in 2025.
Success, however, is not a one-man feat. Dr Bigot frequently reiterates the importance of teamwork and individual accountability at all levels. In his message last week to ITER staff and the seven ITER Members, announcing his acceptance of a second term, he set a familiar tone: "... the most important person for the success of the ITER Project is not the ITER Organization Director-General, but each of you, each of the stakeholders, each of our contractors and suppliers, each of us."
Read the press release in English or French.

Cryolines | Not just any pipes

ma, 21/01/2019 - 18:28


In order to produce and sustain plasmas ten times hotter than the core of the Sun, some essential elements of the ITER machine need to be cooled to temperatures only encountered in the void of outer space. Superconducting magnets and cryopumps will operate at a few degrees above absolute zero—~ 4 K, or minus 269 °C—and the thermal shield will be only slightly warmer (80 K, or minus 193 °C). These temperatures are obtained by circulating a steady flux of cryogenic fluid through a complex network of high-technology piping—the ITER cryolines.
Cryolines begin their long journey in the ITER cryoplant—where the cooling fluids are produced—and continue along an elevated bridge to the Tokamak Building, about 100 metres away. A section of cryoline can host up to six or seven "process pipes," each devoted to a specific fluid, flow direction or function.
Cryolines rarely run straight; instead they bend and turn to adapt to the topography of the worksite, or to snake their way through the congested spaces of the cryoplant and Tokamak Building.
ITER will have approximately 5 kilometres of cryolines ranging from 25 to 1000 millimetres in diameter. Part of India's contribution to ITER, the procurement is split between two companies, France's Air Liquide and India's INOXCVA.
Not just any material can be chosen to transport extremely low-temperature fluids. "Extreme cold makes most material brittle," says Nitin Shah, the technical responsible officer for the ITER cryolines. "As a consequence we need to use special-grade austenitic stainless steel, low in carbon and high in nickel and chromium."
Contraction is another challenge. When exposed to cold, materials retract—and when cold is extreme, contraction is significant. In the ITER cryolines, a 10-metre pipe will shrink in length by 3 centimetres when the cooling fluids begin to flow inside.
The solution for compensating such contraction comes in the form of steel bellows and flexible hoses, made out of an extensible material and placed at regular intervals along both the inner pipes and the outer jackets.
Like frozen food brought home from the supermarket, the cooling fluids flowing in the cryolines must be carefully insulated in order not to warm up during their journey from the cryoplant to the Tokamak Building and back. As the temperature gradient between the fluids and the outside environment is particularly high (on the order of 300 °C) the insulation of the cryolines is particularly sophisticated.
"There are three ways by which heat is transmitted from one environment to another: radiation, convection and conduction," explains Shah. To minimize transmission by radiation, the inner pipes of the cryolines are wrapped with between 30 and 60 layers of glass-fibre/aluminized Mylar insulation. Convection is dealt with by creating a high vacuum within the outer jacket.

And as for conduction, it occurs through solid contact. "As the inner pipes are attached to the inner wall of the cryoline jacket, transmission by conduction is not completely unavoidable," says Shah. "But we can reduce it considerably by using as few support pieces ('spacers') as possible, by optimizing their geometry and, of course, by choosing the least conductive material."
_To_150_Tx_As if all these challenging requirements were not enough, the ITER cryolines must also be particularly robust to resist the forces that could be exerted in case of a quench, which is the sudden loss of magnet superconductivity. During a quench the cooling fluids need to be transferred almost instantaneously from the machine to the quench tanks.
At Indian Domestic Agency contractors Air Liquide (France) and INOXCVA (India), fabrication is approximately 50 percent complete. Newsline recently visited the Indian facility located in the outskirts of Vadodara, an industrial city with a population of more than two million in the western state of Gujarat (see gallery below).
INOXCVA is a company with a quarter-century of experience in cryogenics, and whose Cryo Scientific Division is deeply involved in space applications, the nuclear industry, and all other major technologies involving cryogenics.
The manufacturing of spools—the 2- to 10-metre sections of cryoline that, once assembled at the ITER site, will form the cryoline network—began in 2017 in a specially constructed workshop complete with a clean room devoted to the most delicate and sensitive operations.
For the team at INOX, the challenge in filling the ITER order lay in the stringency of the technical specifications as well as in the quantity of spools to be produced—approximately 700 of them, each with a different shape.
"The ITER cryolines are all angles, bends and turns. Less than 20 percent of the spools we need to produce are straight," says Sanjay Gajera, the quality responsible officer at the INOXCVA facility in Vadodara.
In the large open space of the workshop, dozens of spools are in various stages of fabrication and, indeed, very few are straight. The factory receives the raw pipes from India and Europe (mainly the Ukraine); once cut to the required dimensions and cleaned, the welding process, which is exclusively manual, can begin. "Because of the complex shapes involved it is impossible to use automatic (orbital) welding machines," says Sanjay.
The inner pipes pass through the clean room to be wrapped in insulating tape multilayer insulation before being inserted into their outer jacket. At each stage of fabrication, the pipes are visually inspected and their internal surface and welds are explored by way of "boroscopy" (using a visualizing tool similar to an endoscope), X-rayed and cold tested.
At the end of this process, the spools are sealed at both ends under a slightly pressurized atmosphere of nitrogen to protect them from corrosion and impurities during storage and transport, and until they are assembled and welded on site at ITER by INOXCVA personnel.
The first batches of INOXCVA cryoline spools reached ITER in July 2017 after a one-month sea voyage from India. Installation in the cryoplant is underway; in the Tokamak Building work will begin this summer. The bridge between the two buildings will be in place in 2023, and the cooling fluids should begin circulating in the crydistribution network in 2024 in anticipation of First Plasma scheduled the following year.
Click here to view a video of the fabrication process at INOXCVA.  

Sub-assembly tools | A 12-tonne beam, a crane and a little push

di, 15/01/2019 - 10:24


There is nothing remarkable about lifting a 12-tonne beam. Except when it happens in the spectacular setting of the ITER Assembly Hall, and the beam needs to be fitted with extreme precision into a structure as monumental as the ITER sector sub-assembly tools.
Towering 22 metres above ground, the vacuum vessel sector sub-assembly tools (SSATs) are formidable handling machines that will be used to pre-assemble vacuum vessel sectors with a pair of toroidal field coils and thermal shield segments before integration in the machine.
The assembly of SSAT-1 began in November 2017 and is now complete. Work on its identical twin SSAT-2 started in September the following year and is now entering its final phase.
Part of Korea's contribution to ITER, the tools are assembled by French contractor CNIM. Lessons learned from SSAT-1 have reduced assembly time for SSAT-2 by approximately one-third.
On Wednesday 9 January, installation operations began for some of the last elements: two 12-tonne beams that stabilize the massive pillars of the machine.
Click here to watch a video of the installation.

Toroidal field coils | First ITER magnet arrives this year

ma, 07/01/2019 - 16:59


A major milepost is projected for 2019 as the first of ITER's powerful, high-field magnets is scheduled to arrive from Japan. Let's take a look behind the scenes at the last-stage fabrication activities that are mobilizing the expertise and skill of heavy industry specialists under the responsibility of Japanese QST, the National Institutes for Quantum and Radiological Science and Technology.
Eleven years after completing the signatures on documents specifying technical and quality control requirements for the supply of nine toroidal field coils, the Japanese Domestic Agency is overseeing the last, spectacular sequences on its first production unit.
The toroidal field coils are the ITER magnets responsible for confining the plasma inside the vacuum vessel using high-performance, internally cooled superconductors called CICC (cable-in-conduit) conductors. Following the completion of the single largest superconductor procurement in industrial history, fabrication of the final coils is proceeding in Japan (9 toroidal field coils plus 10 coil structures to be sent to Europe) and Europe (10 toroidal field coils). Each coil is made up of a superconducting winding pack and surrounding stainless steel coil case.
The list of applicable superlatives is long—the toroidal field coils are the largest and most powerful superconductive magnets ever designed, with a stored magnetic energy of 41 GJ and a nominal peak field of 11.8 T. Together they weigh in at over 6,000 tonnes including superstructure, representing 60 percent of the magnetic array on the machine and over one-fourth of the Tokamak's total weight. They require 4.57 km of conductor per coil wound into 134 turns in the central core, or winding pack, of the magnet. And they have required the longest procurement lead-time of any ITER component, with six out of seven ITER Members involved in the production of 500 tonnes of niobium-tin superconducting strand (100,000 km) required for the toroidal field superconducting cables. The first winding pack to come off the assembly line in Japan is currently undergoing final inspection by the industrial consortium of Mitsubishi Heavy Industries/Mitsubishi Electric Corporation. The final sequence of testing involved high voltage tests, helium leak tests, and finally cryogenic tests, during which the winding pack is inserted into a cryostat (see top photo) and cooled to 80 K (-193 ˚ C) to confirm leak tightness. With the successful end of cold testing, the winding pack is now undergoing post-cold-test helium leak tests and high voltage tests and will soon be ready for assembly with its toroidal field coil case. Five other winding packs are in various stages of production.

The 200-tonne case assemblies are also in series production. After successful fitting tests early last year, two have been delivered to Europe for insertion activities and a third will arrive this month; another completed production unit will remain at MItsubishi for the assembly of the Japanese coil that is due at ITER in 2019. The fitting tests are the most delicate stage in the coil case manufacturing process, demonstrating that sub-assemblies manufactured and welded at different factory sites can be successfully paired with gap tolerances as strict as 0.25 to 0.75 mm along 15-metre weld grooves.

Please see the gallery below for a full update on manufacturing progress.

From the crane | When dusk falls

ma, 17/12/2018 - 20:46

There is a magic moment at dusk when the ITER site lights up and the sky still retains some of the light of day. Details that were washed out by the intense daylight or buried in the deep shade jump to the eye as warm yellowish sodium lights, white halogen and the occasional blue-green glow of a welding torch combine to create an unreal atmosphere.

Although familiar by now, this view has no equivalent in the world. This is a giant tokamak being constructed—a unique venture with unique features that the camera loves to capture.

The walk-around continues in the gallery below.


Tokamak Pit | Big steel elbow in place

ma, 10/12/2018 - 22:01

A cryostat feedthrough delivered by the Chinese Domestic Agency has become the first metal component of the machine to be installed in the Tokamak Pit, in an operation orchestrated over two weeks by the ITER Organization.
An activity that began with the transfer of the component to the vicinity of the Tokamak Complex—and that was pursued as the 10-metre, 6.6-tonne component was introduced into the Pit through an opening in the bioshield roof—has now been concluded through the final positioning of the feeder segment in the building.
In the final lift sequence, the elbow-shaped component was lifted by the monorail crane at the bottom of the Tokamak Pit, rotated above the cryostat crown, and lowered into a slim opening that had been left in the concrete circle in anticipation of this very installation sequence. Positioned on a temporary support tool supplied by the Korean Domestic Agency, technicians used cables to draw the horizontal segment of the feedthrough into the bioshield opening, while the vertical segment fell into place between the crown and the bioshield. (See more detail in the photo gallery below.)
Final adjustments were performed through metrology measurements to fall within +/- 2 mm with respect to the Tokamak Global Coordinate System.
If magnet feeders are the essential lifelines of the ITER magnets—carrying electricity, cryogenic fluids and instrumentation cables—"feedthroughs" are the part of the feeder assemblies that cross through the bioshield and the cryostat. This first completed unit had been delivered last year to the Magnet Infrastructure Facilities for ITER (MIFI) where, as a first-of-a-kind component, it underwent high-voltage tests, leak tests and endoscopic inspection.
Ultimately, the feedthrough will be joined by two other components—an in-cryostat feeder (nearest the vacuum vessel) and a coil termination box (outside the bioshield)—to connect to poloidal field coil #4, one of the two largest of the machine's six poloidal field coils (24 metres in diameter.
"A large number of actors played a critical role in the installation operation that concluded last week," notes Bruno Levesy, Group Leader of the In-Cryostat Assembly Section, with satisfaction. "The Domestic Agencies of China (fabrication) and Korea (tooling), the ITER Organization logistics provider DAHER (transport), European Domestic Agency building contractors, ITER's Construction Management-as-Agent contractor, and the French company CNIM, which won the early works contract in the Tokamak Pit. Giobatta Lanfranco (Construction Team) and Bruno were the most involved staff members of the ITER Organization. "It has been a good practice in coordination for the many activities to come."

Manufacturing | In the cradle of the cryostat

ma, 03/12/2018 - 17:51


On the northwestern coast of India, facing the Arabian Peninsula, Hazira is one of the subcontinent's major industrial hubs. Under the still-blazing autumn sun, the landscape is one of refineries, shipyards, power plants, storage tanks and endless queues of oil and container trucks. It is here, at the Larsen & Toubro Ltd manufacturing complex, that a critical ITER component is taking shape.   Between ocean and mangrove, amidst a world of dust and rust, the Larsen & Toubro Ltd "campus" is like an oasis of green and cool. In the mid-1980s, the mammoth Indian conglomerate drained close to one thousand acres of marshland to establish this multi-facility complex.   Thirty years later, the place is a unique aggregation of manufacturing facilities that turn out offshore oil platforms at the rate of 10 to 12 per year and manufacture ships, submarines, tanks, giant boilers and turbines ...   At one kilometre long, the west campus' special steels and forging facility is one of the largest in the world. In an atmosphere that mixes space-age technology with a 19th century steel mill atmosphere, "manipulators" the size of freight train locomotives slowly move amidst giant furnaces and massive steel ingots laid to cool on sand beds. The facility produces more than 40,000 tonnes of finished forgings annually.   Across the road on the east campus, administrative buildings, fabrication facilities, workshops and port installations cover close to one hundred hectares.   This environment is the cradle of the ITER cryostat, the largest of the Tokamak's components—a giant, leak-tight cylinder 30 metres high and 30 metres in diameter that will act as a "thermos" to insulate the ultra-cold magnets from the environment.   From humble beginnings in the form of ingots that look strangely like truncated Doric columns, to the shining stainless steel segments ready to be shipped to the ITER site, it all happens here.   _To_148_Tx_Since late 2015, segments for the ITER cryostat's base section and lower cylinder have been successively forged, machined, finalized, shipped to the ITER construction site, and assembled and welded in the onsite Cryostat Workshop.   In December 2013, as the first mockups were produced to demonstrate and validate welding and manufacturing sequences and techniques, Madhukar Kotwal, then president of Larsen & Toubro Heavy Engineering, told Newsline that despite the company's accumulated experience in manufacturing nuclear and space components, the ITER cryostat was so "special" that it presented unprecedented challenges, both technical and organizational.   Five years later, the challenges have been met and overcome and the manufacturing of the segments for the "huge assembly" of the ITER cryostat is nearing its end.   In the east campus, inside Medium Fabrication Shop #4, work is now underway on the last two orders that Larsen & Toubro is filling for the ITER cryostat: seven segments of the 490-tonne upper cylinder are packed and ready for dispatch; another two are undergoing finishing works and inspections; a segment prototype for the 655-tonne top lid is in the last stage of fabrication; and various tasks are being performed on the "ribs," "flanges," "knuckles," and "crown" that make up a top lid segment (see further technical detail in the photo gallery below.)   Although 7,000 kilometres and three and a half time zones stand between the Larsen & Toubro teams in Hazira and those on the ITER worksite, communication between them is constant. "We have a conference call every single working day," says Chirag Patel, the Larsen & Toubro project manager for the ITER cryostat and in-wall-shielding (see box). "And we will soon be implementing Wi-Fi-connected viewing goggles that will enable us to have a better visual assessment of the ongoing works in the Cryostat Workshop at ITER."   In the summer of 2019, the 12 top lid segments will be shipped to ITER, marking the end of a formidable industrial venture that has spanned two continents and involved hundreds of specialists in both Hazira and at the ITER site in Saint-Paul-lez-Durance.   Click here to watch the "Made in India" video.