Vacuum Vessel

The Spanish contribution to ITER

Spain’s relationship with ITER is especially close as the city of Barcelona hosts the European agency Fusion for Energy, which manages the European contribution to the Project. Spanish research centres—led by CIEMAT and in cooperation with other European partners—play a crucial role in ITER by contributing to the development of diagnostic systems, plasma heating components, test blanket modules, and control and data acquisition systems. The Centre for the Industrial and Technological Development (CDTI) promotes the participation of Spanish industry and acts as a focal point between companies and ITER. For Spanish industry, ITER is a unique opportunity to develop cutting-edge technologies, but also an occasion to foster commercial products in industrial areas outside fusion energy. This cross-fertilization will contribute to the scientific and technological progress in the coming decades. Since 2008, Spanish companies have earned an increasing number of contracts for ITER, with a peak in 2012. According to the latest estimates, Spanish industry has won over EUR 400 million in contracts in a highly competitive market, with many opportunities for participation ongoing. Spanish industrial capabilities cover a wide range of technological areas, making it possible to participate in the fabrication of many ITER components such as the vacuum vessel, magnets, buildings, test blankets modules, plant systems, in-vessel components, remote handling, safety, instrumentation and control and CODAC, to name but a few. Spanish companies have also won important contracts in other fusion facilities such as the European tokamak JET, TJ-II (CIEMAT) and W7X (Germany) and have taken on significant challenges in the supply of components for the Spanish in-kind contributions to the Broader Approach projects IFMIF-E Czytaj dalej...

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 volu Czytaj dalej...

Three cities, two Procurement Arrangements

During the week of 26 August, ITER Director-General Motojima travelled to Russia, visiting three cities and signing two Procurement Arrangements in four days. Accompanied by Deputy Director-General Alexander Alekseev, head of the Tokamak Directorate, the ITER Director-General began his trip at the Institute of Nuclear Physics in Novosibirsk, where he signed the Procurement Arrangement for Equatorial Port 11 Engineering, for the engineering of diagnostic systems into vacuum vessel Port 11. The Budker Institute will be responsible for the scope of work. The Budker Institute already plays a key part in the development of high-tech electron equipment, engineering of diagnostic systems into the vacuum vessel ports, and research into the investigation of high-temperature plasma impact on reactor’s first wall materials as well as developing, manufacturing, and testing equipment for the ITER machine. According to the Head of the Russian ITER Domestic Agency, Anatoly Krasilnikov, equipment development for ITER’s plasma diagnostics engineering will take five to seven years and will require constant interaction with the ITER Project’s other partners. In all, the Budker Institute will develop five engineering systems for ITER’s vacuum vessel ports. The delegation from ITER also visited the Institute of Applied Physics and the enterprise GYCOM in Nizhniy Novgorod, where gyrotron component manufacturing and assembly are conducted as well as the development of infrastructure equipment such as cryomagnetic systems, measurement and technological devices, and part of the energy sources required for the gyrotrons. Procurement of the ITER gyrotrons is a matter of special pride to the Institute of Applied Physics, because it was here that this device was invented. More than half of existing experiment Czytaj dalej...

Melting tungsten for a good cause

Over the past two years ITER physicists and engineers, along with many scientific colleagues within the fusion research community, have been working to establish the design and physics basis for a modified divertor—the component located at the bottom of the huge ITER vacuum vessel responsible for exhausting most of the heat and all of the particles which will continuously flow out of ITER’s fusion plasmas.  Our current Baseline begins plasma operations with divertor targets armoured with carbon fibre composite (CFC) material in the regions that will be subject to the highest heat flux densities. After the initial years of ITER exploitation, in which only hydrogen or helium will be used as plasma fuel producing no nuclear activation, this divertor is to be replaced. The replacement—a variant of the first component but fully armoured with tungsten—would be the heat and particle flux exhaust workhorse once the nuclear phase, using deuterium and then deuterium/tritium fuel, begins. In 2011 the ITER Organization proposed to eliminate the first divertor and instead go for the full-tungsten („full-W”) version right from the start. This makes more operational sense and has the potential for substantial cost savings. By June 2013, the design was at a sufficiently advanced stage and we were confident that the necessary tungsten high heat flux handling technology was mature enough to invite external experts to examine our progress during the full-W divertor Final Design Review.  But making a choice to begin operations with tungsten in the most severely loaded regions of the divertor is not just a question of having a design ready to build.  Tungsten, a refractory metal with high melting temperature (3400 Celsius), is a much more difficult material than carbon when it comes Czytaj dalej...

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.” Czytaj dalej...

India will participate in upper port plug manufacturing

ITER-India and the ITER Organization signed a Memorandum of Understanding (MoU) for the Common Manufacture of Port Plugs on 16 July 2013 during the Unique ITER Team week at ITER. This MoU enables the participation of India in the common manufacture of the upper port plug that includes the Generic Upper Port Plug (GUPP) and applicable customizations. ITER-India is responsible for providing Upper Port No. 9 Integration components, of which Upper Port Plug No. 9 is one of the components. The main functions of the upper port plug are to hold the diagnostics in position, shield diagnostics from neutron streaming and act as the first closing boundary at the vacuum vessel port flange. This upper port plug will be a stainless steel structure of nearly 6 metres in length and a little more than 1 metre in width and height, weighing approximately 25 tons. Czytaj dalej...

Plasma seeking plasma

It has been an unusual July so far in Provence. Thunderstorms have broken over the site almost every afternoon, causing work to be stopped until the storm front moves on. Storms over the ITER platform do not come unannounced: when one approaches, the French storm forecast agency Metéorage (a subsidiairy of Météo-France) sends an alert to security personnel, who activate the appropriate siren. Depending on the distance of the incoming storm, the siren sounds an „orange alert,” stopping only the heavy activity, or a „red alert,” requiring full site evacuation. This spectacular bolt of lightning was captured last Wednesday from a fifth floor window in the ITER Headquarters building after a red alert was sounded. Lightning is a high current electric discharge in the air that generates a ramified column of plasma. This specific bolt might have been looking for its kindred—the plasma that will be created within the ITER vacuum vessel. The place was right but the time some seven years too early. Czytaj dalej...

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 Czytaj dalej...

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 th Czytaj dalej...

Armed and ready to identify leaks

In constructing ITER, one of the key challenges is to ensure a leak-free machine. The US Domestic Agency has recently completed the bulk of delivery for the test equipment required to confirm the vacuum leak-tightness of components as they arrive on site and during the construction of the machine. At right,  vacuum team members are pictured with some of the leak detection tools-of-the-trade: helium spray guns and highly sensitive mass spectrometer-based detectors. „This procurement is the very first US ITER procurement to be delivered to the ITER site,” rejoices Mike Hechler, the responsible officer within the US vacuum team. „Hence it should be celebrated as a real success. Being first we were like guinea pigs having to sort out how to deal with transport, VAT charges, customs, CE marking. It was not easy, but opens up the way for future US deliveries.” „The basic method of leak detection is simple,” explains Liam Worth, member of the ITER vacuum team  and responsible for the test program. „You evacuate your vacuum vessel, surround it with helium gas, and then use the leak detector to look for helium leaking in—these instruments can detect in the minutest quantities.” However the size, complexity and number of the ITER vacuum systems make this a far from simple task. „We estimate that from acceptance to the final commissioning of the machine, no fewer than 94 man-years of vacuum testing will have to be performed.” Czytaj dalej...

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 Czytaj dalej...

Green light for ITER’s blanket design

After three days and 29 presentations, a comprehensive design review with probably the largest participation in the history of the ITER project was completed last week. More than 80 experts from the ITER Organization, Domestic Agencies and industry attended the Final Design Review of the ITER blanket system. „The development and validation of the final design of the blanket system is a major achievement on our way to deuterium-tritium operation—the main goal of the ITER project,” Blanket Integrated Product Team Leader (BIPT) and Section Leader Rene Raffray concluded at the end of the meeting, obviously relieved at the success of this tremendous endeavour. „We are looking at a first-of-a-kind fusion blanket which will operate in a first-of-a-kind fusion experimental reactor.” The ITER blanket system provides the physical boundary for the plasma and contributes to the thermal and nuclear shielding of the vacuum vessel and the external machine components such as the superconducting magnets operating in the range of 4 Kelvin (-269°C). Directly facing the ultra-hot plasma and having to cope with large electromagnetic forces, while interacting with major systems and other components, the blanket is arguably the most critical and technically challenging component in ITER. The blanket consists of 440 individual modules covering a surface of 600 m2, with more than 180 design variants depending on the segments’ position inside the vacuum vessel and their functionality. Each module consists of a shield block and first wall, together measuring 1 x 1.5 metres and weighing up to 4.5 tons—dimensions  that not only demand sophisticated remote handling in view of maintenance requirements during deuterium-tritium operation, but also an approach to attaching the modules which is far from trivi Czytaj dalej...

DivSOL wagon rolls EAST

With the EAST tokamak in the middle of an extended maintenance period—during which the ASIPP team in Hefei, China will take the audacious step of installing an ITER-like, full tungsten divertor in the upper part of the vacuum vessel by the end of this year—what better place to hold the latest in the series of regular meetings of the International Tokamak Physics Activity (ITPA) Topical Group on Divertor and Scrape-Off Layer physics. Known in ITPA circles as the DivSOL TG, this group focuses on issues of importance to ITER in the area of heat and particle exhaust from the tokamak plasma and the unavoidable plasma-surface interactions which occur at the plasma-materials boundary.  Plasma and materials physicists work together within DivSOL to address a host of questions, from movement of material by the plasma and tritium trapping in surfaces, to turbulent transport of heat in the plasma boundary and plasma-facing component lifetime under intense heat fluxes. In common with all ITPA groups, DivSOL is reactive to urgent ITER physics R&D issues and works to find answers to specific requests. One such example is the flurry of activity stimulated by the ITER Organization proposal in autumn 2011 to eliminate one of the two divertors planned for the first years of ITER operation, up to achievement of burning plasmas. The idea is to go the whole way with a single unit in which tungsten (chemical symbol W) would be the only material intercepting the majority of the tokamak heat exhaust. A single divertor would be a major cost saving to the project, but it is a calculated risk: W is a harder material to work with from the plasma point of view than the carbon fibre composite in originally planned first divertor. Finding out just how much of a risk, and making sure that a workable design with qualified technology Czytaj dalej...

ITPA DivSOL wagon rolls EAST

With the EAST tokamak in the middle of an extended maintenance period—during which the ASIPP team in Hefei, China will take the audacious step of installing an ITER-like, full tungsten divertor in the upper part of the vacuum vessel by the end of this year—what better place to hold the latest in the series of regular meetings of the International Tokamak Physics Activity (ITPA) Topical Group on Divertor and Scrape-Off Layer physics. Known in ITPA circles as the DivSOL TG, this group focuses on issues of importance to ITER in the area of heat and particle exhaust from the tokamak plasma and the unavoidable plasma-surface interactions which occur at the plasma-materials boundary.  Plasma and materials physicists work together within DivSOL to address a host of questions, from movement of material by the plasma and tritium trapping in surfaces, to turbulent transport of heat in the plasma boundary and plasma-facing component lifetime under intense heat fluxes. In common with all ITPA groups, DivSOL is reactive to urgent ITER physics R&D issues and works to find answers to specific requests. One such example is the flurry of activity stimulated by the ITER Organization proposal in autumn 2011 to eliminate one of the two divertors planned for the first years of ITER operation, up to achievement of burning plasmas. The idea is to go the whole way with a single unit in which tungsten (chemical symbol W) would be the only material intercepting the majority of the tokamak heat exhaust. A single divertor would be a major cost saving to the project, but it is a calculated risk: W is a harder material to work with from the plasma point of view than the carbon fibre composite in originally planned first divertor. Finding out just how much of a risk, and making sure that a workable design with qualified technology Czytaj dalej...

Management Advisory Committee meets in Barcelona

For the second time in its history, the ITER Council Management Advisory Committee (MAC) convened for an extraordinary session in order to assess the status of the ITER project schedule and the implementation of corrective actions. The meeting took place from 18-19 March at the headquarters of the European Domestic Agency in Barcelona in the attendance of high-level representatives of the ITER Organization and seven ITER Members. Since the last special MAC meeting held in August 2012, the ITER Organization has worked closely with Domestic Agencies to complete the integration of Detailed Work Schedules (DWS)—detailed schedules that exist for every component or system. The IO and DAs completed the integration of the remaining DWS, namely Main Vacuum Vessel, IC Antenna, PF Coils and TF Structure, which will allow for monitoring of the schedule. MAC requested that the Unique ITER Team continue to make significant efforts to take action focusing on super-critical milestones and to take all possible measures to keep to the Baseline schedule. The ITER Organization and Domestic Agencies are committed to doing their best to implement this request. Czytaj dalej...

Hot, hotter, hottest

Temperature, from a physicist’s perspective, is not only a measure of hot or cold. It is also a measure of the energy carried by atoms and molecules: temperature tells us how rapidly these atoms or molecules move within a solid, a liquid or a gas. Temperature is different from heat. To feel heat on your fingers, you need density: the higher the density, the more heat is transferred to your skin—this explains why a neon tube containing a very hot (~10,000°C) but very tenuous plasma can be touched without harm. In temperature, there is a theoretical absolute cold („absolute zero”) but no absolute hot: a particle can always move more rapidly but it cannot be more immobile than … immobile. When we talk about a 150- to 300-million-degree plasma in ITER, we’re describing an environment where particles (the deuterium and tritium ions and the freed electrons) move around at tremendous speed: so fast and with such a high energy that when they collide head on the miracle of fusion happens. The electromagnetic barrier that stands between nuclei is overcome and the nuclei can fuse. How will the ITER plasma be brought to such extreme temperatures—ten times higher, or more, than the core of the Sun? Plasma heating in ITER will begin with an electrical breakdown, quite similar to what happens when we turn on the switch of a neon light. In the very tenuous gas mixture that fills the vacuum vessel (one million times denser than the air we breathe) the electrical discharge strips the electrons from the atoms and the gas becomes a plasma—a particle soup of electrically charged electrons and ions. „The electrons from the current collide with and communicate their energy to the ions from which they have been stripped,” explains Paul Thomas, ITER Deputy Director-General for CO Czytaj dalej...

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. Czytaj dalej...

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 en Czytaj dalej...