Who’s got the biggest?


At ITER, we don’t brag. But we do like to mention the exceptional dimensions of the machine we are building: the ITER Tokamak will indeed include components that, in their category, are by far the largest in the world.

In talks and presentations to the public it has become routine, for instance, to assert that the ITER cryostat will be the largest high-vacuum chamber ever built.

But recently, a young postdoc attending a presentation on ITER at the Institute of Plasma Physics in Prague took issue with this claim. It’s NASA’s Space Power Facility, the student said, that holds the blue ribbon for the largest high-vacuum chamber.

Located in Sandusky, Ohio (USA), the Space Power Facility was built in 1969 to create an environment comparable to that encountered in deep space, on the Moon or on planet Mars. It comes complete with high-vacuum, extreme cold (down to minus 195°C) and solar radiation simulation.

NASA has been using the facility for more than four decades to expose rocket components, space capsules, landing vehicles and satellite hardware to the harsh conditions of outer space. Its futuristic setting has also inspired movie makers: in 2012 the opening sequences of the blockbuster The Avengers were filmed there.

The cylindrical vacuum chamber is 30 metres in diameter and 37 metres in height—bigger, it’s true, than the 29.4 x 29 metre ITER cryostat. There is however an important difference between the two: while the aluminium Space Power Facility’s test chamber is spectacularly empty (after all, rocket stages have to fit in) the steel ITER cryostat is a very crowded place.

In ITER, because of the volume occupied by components such as magnets, support structures, the thermal shield and the vacuum vessel itself, the pump volume inside the cryostat—that is, the total volume of the chamber minus that of the components—is reduced to 8,500 cubic metres. At the NASA facility, it is almost three times larger (23,500 cubic metres).

In order to achieve high vacuum up to 10-6 Torr, one millionth time more tenuous than the Earth’s atmosphere, both installations use mechanical roughing pumps to go down to ~ 0.1 Torr, and then cryopumps to achieve the required high vacuum. While NASA’s installation can achieve high vacuum in 8 to 12 hours, the ITER cryostat will require about twice this time.

„However, the two systems are quite different," notes Matthias Dremel, an engineer in the ITER Vacuum Section. „The ITER cryostat contains thermal shields cooled to 80 K that act as pumps by condensation of the gases. What’s more, the magnets behind the thermal shield, cooled to ~4K, also act as pumps by condensation.”

Because these components are extremely cold, they significantly contribute to removing the impurities that remain in the chamber. Atoms, molecules and particles are all captured by cold surfaces: the more intense the cold … the more irresistible its holding power.

In the ITER cryostat and in NASA’s Space Power Facility we have two high vacuum chambers of approximately the same size but the latter, however spectacular, is but a big empty aluminium cylinder. The ITER cryostat, on the other hand, is a highly complex structure that must remain absolutely leak-tight despite the thousands of lines and feed-throughs that penetrate it for cryo, water, electricity, sensors, etc.

So it’s a NASA win (but not by much) when it comes to size, but when it comes to complexity—the ITER cryostat remains unchallenged by far.

Korean contract advances neutral beam ports

The Korean Domestic Agency signed an important contract in July for the fabrication of neutral beam port in-wall shielding with Korean supplier Hyundai Heavy Industries Co., LTD (HHI). Through this contract, installation of the in-wall shielding into the port stub extensions will begin in mid-2015 with fabrication completed by early 2016. Hyundai Heavy Industries is also manufacturing two sectors of ITER vacuum vessel as contractor to the Korean Domestic Agency, as well as seventeen equatorial ports and the nine lower ports

The vacuum vessel’s neutral beam ports are composed of a connecting duct, port extension, and port stub extension. The spaces between the inner and outer shells of the port extension and port stub extension are filled with preassembled blocks called in-wall shielding. The main purpose of in-wall shielding is to provide neutron shielding for the superconducting magnets, the thermal shield and the cryostat.

In order to provide effective neutron shielding capability with the cooling water, 40-millimetre-thick flat plates (steel type 304B4) are used in almost all areas of the volume between port shells.

In-wall shielding is composed of shield plates, upper/lower brackets and bolt/nut/washers. Pre-assembled 368 in-wall shielding blocks will be assembled into the neutral beam port extension and port stub extension during port fabrication, while 160 field joint in-wall shielding blocks will be assembled after field joint welding on the ITER site. The total net weight of all neutral beam in-wall shielding approximates 100 tons.

Ki-jung Jung, Director-General of the Korean Domestic Agency, commented during the signature: „ITER Korea takes very seriously the demands of the vacuum vessel schedule and quality requirements by ITER.”

A traditional Indian blessing for the Cryostat Workshop


In the Indian pantheon, Ganesha is the one who can remove the hurdles from the path of our human endeavours. In India, anything of importance—a wedding, journey or construction project—begins with an invocation to the elephant-headed deity.

Since a small portion of the ITER platform has been made available to the Indian Domestic Agency for the construction of the Cryostat Workshop, it was natural to place this football-field-sized piece of India under the protection of the „Remover of Obstacles.”

Throwing a bridge between the high-technology world of ITER and the Indian tradition of times immemorial, Bharat Doshi, Cryostat Section leader, first explained to his guests during a ceremony held on 6 June how the giant ITER cryostat will be assembled from 54 segments manufactured in India.

He then proceeded to „break the coconut” and share the coconut meat among the guests—a ritual that is also meant to appease Mother Earth, whose tranquillity will soon be disturbed by the construction works.

Once every guest had broken a coconut, a large excavator symbolically scratched the earth where the 26-metre-high, 110-metre-long Cryostat Workshop will soon be erected.

The same Indian company (Larsen & Toubro Ltd) that will manufacture the cryostat will also build the Workshop and manage the assembly and welding activities all the way through to the final integration of the cryostat into the machine.

„We have already launched the procurement process for the raw material,” explained Philippe Tollini, Larsen & Toubro’s director for Europe and Russia. „We are presently in the manufacturing design stage, which will be completed by September. We should begin to receive the first cryostat segments from India at the end of 2014, beginning of 2015.”

„The cryostat is an essential part of the ITER installation,” explained ITER Deputy Director-General Rem Haange. „It has to be absolutely leak-tight and its assembly requires kilometres of welding. It is a tough job not only to manufacture but also to assemble.”

Last fall, Larsen & Toubro awarded the construction of the 5,500 square-metre Cryostat Workshop to the French company Spie-Batignolles, which was part of the consortium that built the adjacent Poloidal Field Coils Winding Facility.

Construction should begin in earnest in the coming weeks and take a year and half.

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.

In Korea, a week of meetings for key ITER components


An important week of meetings took place recently in Korea for the ITER vacuum vessel and thermal shield—for both of these key components industrial suppliers have been selected and manufacturing, pre-manufacturing or kick-off works have begun.

The 52nd ITER Vacuum Vessel Integrated Product Team (IPT) meeting and Domestic Agency collaboration meeting held on 8-10 April brought together over 30 experts from the ITER Organization, the European, Indian, Korean and Russian Domestic Agencies, and Korean industry (Hyundai Heavy Industry & AMW). During meetings hosted at the National Fusion Research Institute (NFRI) and at Hyundai Heavy Industry, participants shared the technology and experience of fabrication of the ITER vacuum vessel, ports and in-wall shielding, and discussed the development pathway for fabrication issues. A visit was organized to the KSTAR Tokamak at NFRI.

During a bilateral collaboration meeting held on 11 April, participants from the Korean and European Domestic Agencies—plus industrial suppliers Hyundai Heavy Industry and AMW—focused more particularly on the new technologies for fabrication of ITER vacuum vessel sectors, especially welding, nondestructive examination (NDE) and optical dimensional measurement. All parties agreed that such valuable collaboration would be continued in the future.

On Friday 12 April, the kick-off meeting for the ITER thermal shield was held—this key component will be installed between the magnets and the vacuum vessel/cryostat in order to shield the magnets from radiation. The contract for the design and fabrication of the thermal shield was awarded by the Korean Domestic Agency in February to SFA Engineering Corp, which is also the supplier selected by Korea for ITER’s assembly tooling. SFA presented the implementation plan for the procurement of the thermal shield during the meeting.

More than 20 responsible persons from the Korean Domestic Agency, SFA and the ITER Organization were present including Domestic Agency head Kijung Jung, SFA Chief Operating Officer Myung Jae Lee, and head of the ITER Vacuum Vessel Division Carlo Sborchia. Prior to the kick-off meeting, representatives from ITER and the Korean Domestic Agency agreed to collaborate closely to solve urgent design change requests related to assembly and interface issues.

„The thermal shield is one of the most critical procurement items in the ITER project. We will do our best in collaboration with the ITER Organization for its successful procurement,” stressed Kijung Jung.

A "Little India" on the ITER worksite


Beginning in December 2015, the first of the ITER cryostat’s components will arrive on site. A part of India’s in-kind contribution to the project, these 54 segments are among the largest and heaviest of the whole Tokamak assembly. They will have to be  preassembled into four sections before being transported to the Assembly Building.

The pre-assembly operations will take place in a dedicated temporary workshop located on the northeast corner of the ITER worksite, slightly set back from the PF Coil Winding Facility. The workshop will be built and operated by the Indian Domestic Agency.

As stipulated in the agreement that the ITER Organization and the Indian Domestic Agency signed last Friday 19 April, this small „territory”, the size of a football field (50 x 120 m), will be made available to  the Indian Domestic Agency. Acting as building owner on this portion of the ITER worksite, the Indian Domestic-Agency will observe French labour laws and regulations.

Over the past two years and in addition to the preparation of the agreement, the ITER Building Site and Infrastructure Directorate, supported by Legal Affairs, prepared the administrative files pertaining to the environmental authorisations and building permit necessary for the construction and operation of the temporary workshop.

Work on the steel-framed workshop should begin in the coming weeks and last for 18 months. Once the building is completed, Larsen and Toubro Ltd, the Indian company that was awarded the contract for the fabrication and assembly of the ITER Cryostat in August 2012, will have some 50 people on site, and many more, locally subcontracted, once the actual assembly work begins.

The Sun never sets on the CODAC empire


Every year in February, when almond trees begin to bloom in Provence, the ITER CODAC team releases a new version of the CODAC Core System.

The 2013 edition (CODAC Core System v 4.0) is more robust, comes with a better operator interface, offers more features, and supports plant systems that need „fast control,” for example plasma control systems that have to react within a strictly defined period of time. „Version 3.0 did it okay,” says ITER Control System Division Head Anders Wallander. „Version 4.0 does it better.”

CODAC (Control, Data Access and Communication) can be described as a software conductor that orchestrates the dialogue between the hundred-odd ITER plant systems …”the system of systems that makes one entity of everything” … the lingua franca that allows the magnets, blanket, tritium plant, cryostat and diagnostics to exchange signals and share information.

Working for the ITER project here and abroad, 55 organizations (Domestic Agencies, fusion labs, contractors) are presently using the CODAC Core System. An infrastructure has been set up to distribute the software to these and future organizations and to keep track of versions used. Training and user support is also provided.

The software package has recently demonstrated its efficiency on the Korean tokamak KSTAR and celebrated its „First Plasma,” so to speak, last June at the Frascati Tokamak Upgrade (FTU) project in Italy.  „The ITER CODAC system is truly becoming a world language,” says Anders.

CODAC is already implemented and deployed to monitor the power consumption on the ITER site, providing the „power people” with a global view and data with which to charge the different contractors operating on site. „With these pilot applications, we’re demonstrating that the system meets our expectations,” says CODAC System Engineer Franck Di Maio. „We’re demonstrating the system’s credibility.”

_To_44_Tx_CODAC users throughout the world are no different from any personal software user: switching to an upgrade is both exciting and challenging. „Although we provide support for older versions, we want to convince companies to upgrade. And the way to do it is to provide new features and make the upgrade easy.” In Franck Di Maio’s v 4.0 User Manual, the list of changes, fixed bugs, and enhancements of all kinds occupy no less than six pages …

Optimizing, upgrading and adapting ITER CODAC is „a process that will never end,” says Anders. „There will always be new requirements—this is the main difference between an experimental facility and a power plant.”

Korea awards contract for ITER thermal shields


The Korean Domestic Agency signed a contract with SFA Engineering Corp. for ITER thermal shields on 28 February. The contract covers the detailed design of manifolds/instrumentation, the manufacturing design and the fabrication of the thermal shield system. „For us, this is a big step forward for the Korean contribution to ITER,” said Myeun Kwon, president of the National Fusion Research Institute, after the signing.

SFA is a leading company in industrial automation with much experience in the procurement of advanced equipment related to fusion, accelerator, and space technology. SFA was deeply involved in the manufacturing and assembly of the Korean tokamak KSTAR.

The ITER thermal shield will be installed between the magnets and the vacuum vessel/cryostat in order to shield the magnets from radiation. The thermal shield consists of stainless steel panels with a low emissivity surface (<0.05) that are actively cooled by helium gas, which flows inside the cooling tube welded on the panel surface. The temperature of helium gas is between 80 K and 100 K during plasma operation. The total surface area of the thermal shield is approximately 4000 m2 and its assembled body (25 m tall) weighs about 900 tons.

The key challenges for thermal shield manufacturing are tight tolerances, precision welding, and the silver coating of the large structure. The thermal shield also has many interfaces with other tokamak components. „The Korean Domestic Agency is satisfied with this contract because the thermal shield is one of the most critical procurement items in the ITER project. We will do our best in collaboration with the ITER Organization to successfully procure the ITER thermal shield,” said Hyeon Gon Lee, DDG of the Korean Domestic Agency, on the occasion of the contract signature.

EUR 83 million contract signed for Liquid Helium Plant



The ITER Tokamak will rely on the largest cryogenic plant (cryoplant) infrastructure ever built. Three liquid helium plants, working in parallel, will provide a total average cooling capacity of 75 kW at 4.5 K and a maximum cumulated liquefaction rate of 12,300 litres/hour.

On Tuesday, 11 December, ITER Director-General Osamu Motojima and the Managing Director of Air Liquide Advanced Technologies, Xavier Vigor, signed the contract for ITER’s three identical liquid helium (LHe) plants. The contract comprises the design, manufacturing, installation and commissioning of the LHe plants, which are adapted to the long-term, uninterrupted operation of the ITER Tokamak. The contract is worth EUR 83 million.

The cryoplant and cryo-distribution system will supply cooling for the ITER superconducting magnets to confine and stabilize the plasma. They will also provide the refrigeration for the cryosorption panels that are necessary to evacuate the helium ashes stemming from the fusion reaction and to assure the required vacuum for the cryostat and the vacuum vessel. All these users require helium cryogen at different temperature levels ranging from 4.5 K, to 50 K and up to 80 K.

The key design requirement is to cope with ITER’s large dynamic heat loads ranging from 40 to 110 kW at 4.5 K mainly deposited in the magnets due to magnetic field variation and neutron production from deuterium-tritium fusion reactions. At the same time, the system must be able to cope with the regular regeneration of the cryopumps.

Manufacturing of the LHe plant main components will start after design finalization in 2014. The first compressor station will be delivered at the end of 2015 and the LHe plants will be ready for the cool-down of sub-systems in 2018.

„This is a major milestone not only for the cryogenic system but for the whole project,” said the Head of the ITER Plant Engineering Division, Luigi Serio. „The contract covers the principal component that will drive the cool-down of the machine, seting the pace toward First Plasma.”

„We are very happy and excited to participate in the great ITER adventure,” Xavier Vigor said. „Be assured that we, the team from Air Liquide, are fully committed to making ITER a success.”

Air Liquide is the world leader in gases for industry, health and the environment, and is present in 80 countries with 46,200 employees. Oxygen, nitrogen, hydrogen and rare gases have been at the core of Air Liquide’s activities since its creation in 1902. In 2011, the Group’s revenues amounted to EUR 14.5 billion, of which more than 80% were generated outside France.

"Low-voltage" review opens way to contracts


Coil instrumentation in ITER consists of some 3,000 sensors whose function is to monitor the essential parameters of magnets during ITER operation.

A EUR 25 million package, coil instrumentation forms one the few direct purchases of the ITER Organization and the only fund procurement of the Magnet Division. The components will be delivered by the ITER Organization to the Domestic Agencies involved in coil procurement.

Cryogenic and mechanical instrumentation components („low-voltage” components) account for about one-third of the package’s value. Measuring temperature, displacement, strain, and deformation, the low-voltage sensors are critical. The Head of the Magnet Division, Neil Mitchell, explains: „These components cannot be maintained once they are installed. If one fails, it is lost. Of course there are redundancies, but we have to do our best to guarantee they will operate for 30 years in the harsh cryostat environment.”

On 13-14 December, all of the low-voltage components were reviewed by a panel that included members of the different ITER departments and directorates, specialists from the Domestic Agencies, and also internationally reputed external experts.

This was the third Manufacturing Readiness Review organized by the ITER Magnets Division over the last two months. The first one was conducted on the safety class quench detection system on 23 October; the second on 29-30 November for investment protection quench detection and related high voltage components.

Last week’s low-voltage review panel was chaired by Michel Huguet, a major figure in the history of the ITER project who joined fusion research in 1969 at CEA, spent 19 years at JET, and eventually headed the ITER Joint Work Site at Naka (Japan).

„The panel members were quite satisfied—I could even say impressed—by the quality of the work accomplished. Processes and strategies appear to be heading in the right direction.”

Now that the results of the qualification tests have been reviewed (ITER uses laboratories located at CERN) the next step is to release the contracts for low-voltage components, which should be accomplished in the first half of 2013.

Crowning the cryostat from below


Columns are as old as civilization: for thousands of years, they have provided architects and engineers with a simple and sturdy solution to support heavy loads while leaving room to move around on the ground below.

This traditional and reliable solution was to be implemented in ITER: a circular arrangement of 18 steel columns was to support the cryostat ring—the thick steel component that acts as a mechanical interface between the combined mass of the cryostat and Tokamak (25,000 tons) and the Tokamak Complex basemat.

Columns do a great job supporting large, static loads. However under particular circumstances during ITER Tokamak operation, mechanical, magnetic, or thermal loads, singly or combined, could add up to generate considerable stress on the columns.

In the case of a vertical displacement event, for instance, the Tokamak could „up-lift”; in the case of a cryostat ingress cooling event, the cryostat could „shrink”…

Once refined, models and simulations showed that under certain conditions the load transfer to the basemat by way of the columns was not totally satisfying. For ITER Safety Security and Quality (SQS), this was clearly a potential safety issue. „As the Tokamak Complex basemat could not be modified, it was imperative to develop an alternate solution to the columns. In this, the expertise of Design Integration Section was fundamental,” explains head of the ITER Licensing Cell Joëlle Elbez-Uzan.

Thus began, early in 2012, a ten-month collaborative effort involving ITER’s Safety, Quality & Security; Building and Site Infrastructure; Technical Integration; Cryostat; Assembly; Safety; and Magnet teams, as well as the European Domestic Agency F4E and their Architect Engineer, Engage.

„The light eventually came from  Engage’s design project leader, Peter Sedgwick,” recounts ITER’s Nuclear Buildings Section leader Laurent Patisson. „He suggested we mobilize the resistance capacity of the three-metre-thick concrete bioshield wall that surrounds the cryostat—something we had not fully investigated …”

The exceptionally thick and strong bioshield, which stands approximately three metres away from the cryostat, held the solution indeed. „The idea is to replace the 18 steel columns with a concrete 'crown'. Every 20 degrees, the crown would be connected to reinforced concrete walls radially anchored into the bioshield. It’s a clever and efficient solution to distribute the efforts evenly…”

Faced with a similar problem, the architects of Notre Dame Cathedral, in the 13th century, developed a similar solution. „By positioning flying buttresses at regular intervals around the Cathedral’s nave, they were able to evenly distribute the loads of the edifice’s walls, explains Joëlle.

In the ITER Tokamak however, every design modification is bound to impact other components. Designers soon realized that one of the radial walls connecting the crown to the bioshield was competing for space with the magnet feeder for poloidal field coil number 4.

An early option called for compensation by way of a set of concrete beams. „However such a singularity in the crown support system would have made the structural capacity demonstration difficult,” explains Laurent.

Working closely with the Magnet and Technical Integration Divisions and the Building & Site Infrastructure Directorate, a solution was eventually reached, which resulted in the proposed cryostat support system regaining its symmetry.

All in all, as stated in the preliminary assessment on the capacity of the new cryostat support, the new design „could result in a more integral and compact solution, with many potential advantages from a mounting and constructability point of view, as well as from a global structural capacity perspective.”

The cryostat ring and the concrete crown that supports it would be connected by way of an arrangement of 18 spherical bearings acting like ball-and-socket joints. Such bearings, which are also used in large bridges, allow for the smooth transfer of horizontal and rotational forces.

Needless to say, all these components will have to retain quality and functionality in a rather harsh environment, where radioactivity will be high and cold very intense—reaching -100°C in the vicinity of the cryostat ring.

ITER Safety Security and Quality and Buildings & Site Infrastructure are now preparing the Support Robustness Demonstration document, which will be submitted to the French Safety Authority (Autorité de Sûreté Nucléaire, ASN) in January.

When the Demonstration is validated, work will resume inside the Tokamak Seismic Pit where the 1.5-metre-thick Tokamak Complex basemat will be poured.

ITER is well underway


The Eleventh ITER Council convened last week at the ITER site for a two-day meeting that brought together the high-level representatives of the seven ITER Members.

As approximately 100 people took their places in the solemn setting of the new Council Room, Director-General Osamu Motojima welcomed the participants, adding, „I would like to take this opportunity to thank the Members, in particular Europe, the Host Party, and Agence ITER France for providing the project with the ITER Organization Headquarters building where staff is nearly fully installed.” 

The Council noted the strong measures that have been taken by the ITER Organization and the Domestic Agencies to realize strategic schedule milestones and to develop new corrective measures for critical systems such as buildings, the vacuum vessel, the cryostat, and the superconducting magnets. Delegates urged further corrective actions to improve schedule execution and to seek additional savings.

Delegates welcomed the integrated project management approach proposed by the ITER Organization to enhance collaboration between the ITER Organization and the Domestic Agencies, an approach, according to Director-General Motojima, to „cooperate even more closely for the implementation of ITER.”

The ITER Council also celebrated the recent major licensing milestone for ITER, the strong pace of construction activities at the ITER site, and the manufacturing activities well underway in all ITER Members.

The next ITER Council meeting is scheduled to take place in Japan in June 2013.

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

"ITER is well underway"


The Eleventh ITER Council convened last week at the ITER site for a two-day meeting that brought together the high-level representatives of the seven ITER Members.

As approximately 100 people took their places in the solemn setting of the new Council Room, Director-General Osamu Motojima welcomed the participants, adding, „I would like to take this opportunity to thank the Members, in particular Europe, the Host Party, and Agence ITER France for providing the project with the ITER Organization Headquarters building where staff is nearly fully installed.” 

The Council noted the strong measures that have been taken by the ITER Organization and the Domestic Agencies to realize strategic schedule milestones and to develop new corrective measures for critical systems such as buildings, the vacuum vessel, the cryostat, and the superconducting magnets. Delegates urged further corrective actions to improve schedule execution and to seek additional savings.

Delegates welcomed the integrated project management approach proposed by the ITER Organization to enhance collaboration between the ITER Organization and the Domestic Agencies, an approach, according to Director-General Motojima, to „cooperate even more closely for the implementation of ITER.”

The ITER Council also celebrated the recent major licensing milestone for ITER, the strong pace of construction activities at the ITER site, and the manufacturing activities well underway in all ITER Members.

The next ITER Council meeting is scheduled to take place in Japan in June 2013.

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

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.



Measuring current with light

At the Belgian Nuclear Research Center SCK•CEN in Mol, engineers and scientists are developing a system that should enable ITER to measure plasma current in a new fashion. In contrast to the present-day inductive system, the measuring principle developed by the Belgian researchers is ideal for very long shots or even steady state current measurements without the need of signal integration with time.
The measurement is based on a fully optical principle: polarized light is launched in an optical fibre. Following Faraday’s law, the light polarization plane is rotated if a magnetic field is applied along the light path. By surrounding the vacuum chamber with a fibre loop, the current of the plasma is completely enclosed. It follows from the Ampere law that the total rotation angle is directly proportional to the enclosed current.

Up until now such systems were only applied for much lower currents and in environments less harsh than that of the ITER Tokamak where radiation, temperature, vacuum, vibrations etc., make existing designs unusable.

The SCK•CEN, with a long experience in radiation-resistant fibre optics, is pursuing a sensor design based on fibres with limited sensitivity to radiation. As, due to the environment, it can’t be ruled out that the optical fibre may be compromised (i.e., a darkening of the fibre due to irradiation), the sensing fibre could be replaced by a simple intervention from outside of the cryostat: the fibre, installed in a stainless steel tube, could be replaced using a pressurized-air fibre blowing technique. If so, ITER would have the benefit of a measurement system that is easily replaceable. 

In practice, however, designing a suitable fibre blowing system in compliance with ITER geometry is a serious engineering challenge. To test the design on a real scale the SCK•CEN installed a 12-metre-high x 7-metre-wide cross-sectional drawing of ITER and positioned the stainless steel tube that will guide the fibre optics along its path around the vessel. The first tests showed that the principle is realistic and will allow for easy replacement of the fibre. The Fiber Optics Current Sensor (FOCS) principle demonstration also comprises ongoing tests at Tore Supra and Textor.
If successful, these efforts will result in the installation of three such measuring fibres around the ITER vacuum vessel. The engineering challenges are being addressed in a collaboration between SCK•CEN and the IRFM (Institut de Recherche sur la Fusion Magnétique) in Cadarache.

While plasma current measurements are a traditional diagnostic technique, the SCK•CEN researchers are investigating whether further information can be gleaned from the light signal travelling along the fibre. Detailed analysis of the return signal may result in information on the distributed magnetic field and temperature variations. Possibilities that are still under development …


Larsen & Toubro Ltd will manufacture ITER Cryostat

The ITER cryostat will be the world’s largest high-vacuum pressure chamber ever built. On 17 August, the contract for the manufacturing of the 3,800 ton steel-structure was signed with the Indian company Larsen & Toubro (L&T) Ltd.

The cryostat forms the vacuum-tight container surrounding the ITER vacuum vessel and the superconducting magnets – essentially acting as a very large refrigerator. It will be made of stainless steel with thicknesses ranging from 50 mm to 250 mm. The structure will have to withstand a vacuum pressure of 1 x 10 -4 Pa; the pump volume is designed for 8,500 m3. Its overall dimensions will be 29.4 meters in diameter and 29 meters in height. The heavy-weight will bring more than 3,800 tons onto the scale – making it the largest vacuum vessel ever built out of stainless steel.

The cryostat will have 23 penetrations allowing internal access for maintenance, as well as over 200 penetrations—some as large as four metres in size – providing access to the vacuum vessel for cooling systems, magnet feeders, auxiliary heating, diagnostics, and the removal of blanket and parts of the divertor. Large bellows are used between the cryostat and the vacuum vessel to allow for thermal contraction and expansion in the structures.

India, being one of the seven Members of the ITER project, is in charge of procuring the cryostat. On 17 August, Shishir Deshpande, Project Director ofITER-India and Anil Parab, Vice President of the L&T Heavy Engineering division, signed the contract for manufacturing of the ITER cryostat.

The design of the ITER cryostat represented a huge international endeavour involving engineers and technicians from both the ITER Organization and the Indian Domestic Agency. „The cryostat is an essential part of the ITER machine. Seeing this huge component taking shape in the factory is certainly important and encouraging news. It means that the ITER project has entered a decisive phase,” ITER Director-General Osamu Motojima said. 

The cryostat will be manufactured by the Heavy Engineering division of L&T at its Hazira plant, near Surat in Western India, in the state of Gujarat. It will be dispatched in 54 modules to the ITER site in Cadarache, as it cannot be transported in its entire size. Pre-assembly of the cryostat modules will be done in a temporary workshop at the ITER site and then transported to the tokamak pit where they will be welded together by using the advanced „narrow groove all position gas tungsten arc welding technique”.

Mr. M.V. Kotwal, Member of L&T board and President of L&T Heavy Engineering stated: "L&T is proud to be part of this mammoth global collaborative research to build a greener planet.”