EFDA CV shapesSome people believe the triangular shape of the pyramids has special powers. Plasma physicists also have strong opinions about shapes, too, but it is not superstition: it’s all about how to get the maximum performance out of a fusion experiment. The power that interests physicists is not mystical, it is fusion power. Changing the shape of the plasma can lead to higher stability at its edge. This leads to higher density, and therefore more power.

The champion of plasma shaping is the TCV tokamak (Tokamak à Configuration Variable) at the Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland. With its 16 poloidal shaping coils it can achieve an astounding array of plasma geometries, not just triangular and round, but square, pear-shaped,  double-lobed like the number eight or the picturesquely-named “snowflake”. 

The original rationale for departing from the conventional circular cross-section was a practical engineering consideration. The design team of the first large tokamak, JET, realised it is much easier to support D-shaped coils as they sit closer into the central column - conventional circular coils would need substantial support structures to prevent them drooping. However it was soon found that performance was enhanced by this shape: the plasma sits tighter around the central column, which is where the inside sections of the toroidal electromagnets sit closer together. This means the magnetic field is stronger, which makes for the better performance.

At JET the six poloidal shaping coils around the outside of the torus can be used to emphasise the triangularity – the coils at the apices of the triangle ( top and bottom of the torus, and two on the horizontal plane) are run in the same direction as the central solenoid, effectively pulling the apices of the triangle further out, while the two coils at 45 degrees above and below the midplane are run in the opposite direction, flattening the rounded sides of the triangle. The result is far from a true triangle, it is more D-shaped, but a considerable enhancement on the circular cross-section.

What these experiments with plasma geometry have shown is that the creation of a shape with better confinement has a downside. The high-confinement modes inevitably lose energy through turbulent events known as an edge-localised modes (ELMs) – and the geometries with higher confinement lead to less frequent, but more powerful ELMS.

Nonetheless the design team for ITER has opted for a triangular plasma, to maximise the power output of the device, and is trialling a number of other methods to reduce ELMs, such as specifically installed localised coils, or injecting pellets of frozen fuel to trigger higher frequency, but less damaging ELMs.

The plasma shape plays another major role in a tokamak, by determining where the plasma touches the walls. It is here that TCV’s snowflake geometry is significant: It gains its name not from its cross section, which is more-or-less triangular, but from the six-fold pattern of the magnetic field lines where it touches the divertor. This extended shape spreads the heat load from the plasma, helping to overcome the material challenges for future fusion devices

If these plasma shapes are successful in ITER then perhaps the respect the ancient Egyptians had for the triangular shape of the pyramids will re-surface in the future, as society begins to rely on a generation of high triangularity fusion power plants!

 

Source: EFDA

 

iter blanketAfter 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 trivial when considering the enormous electromagnetic forces. 
The first wall is made out of shaped "fingers." These fingers are individually attached to a poloidal beam, the structural backbone of each first wall panel through which the cooling water will be distributed. Depending on their position inside the vacuum vessel, these panels are subject to different heat fluxes. Two different kinds of panels have been developed: a normal heat flux panel designed for heat fluxes of up to 2 MW/m2 and an enhanced heat flux panel designed for heat fluxes of up to 4.7 MW/m2.
The enhanced heat flux panels are located in areas of the vacuum vessel with greater plasma-wall interaction and they make use of the hyper-vapotron technology which is similar to that used for the divertor dome elements. All panels are designed for up to 15,000 full power cycles and are planned to be replaced at least once during ITER's lifetime. A sophisticated R&D program is currently under way in Japan for the development of remote handling tools to dismantle and precisely re-position the panels. 
Due to the high heat deposition expected during plasma operation—the blanket is designed to take a maximum thermal load of 736 MW—ITER will be the first fusion device with an actively cooled blanket. The cooling water is fed to and from the shield blocks through manifolds and branch pipes. Furthermore, the modules have to provide passage for the multiple plasma diagnostic technologies, for the viewing systems, and for the plasma heating systems.
Because of its low plasma-contamination properties, beryllium has been chosen as the element to cover the first wall. Other materials used for the blanket system are CuCrZr for the heat sink, ITER-grade steel 316L(N)-IG for the  steel structure, Inconel 718 for the bolts and cartridges, an aluminium-bronze alloy for the pads that will buffer the electromechanical loads acting on the segments, and alumina for the insulating layer. 
The procurement of the 440 shield blocks is equally shared between China and Korea. The first wall panels will be manufactured by Europe (50%), Russia (40%) and China (10%). Russia will, in addition, provide the flexible supports, the key pads and the electrical straps. The assembly of the blanket is scheduled for the second assembly phase of the ITER machine starting in May 2021 and lasting until August 2022. The work will be performed with the help of two in-vessel transporters working in parallel.
In assessing the work presented at the Final Design Review, Andre Grosman, deputy head of Magnetic Fusion Research Institute at CEA and chair of the review panel, enthusiastically commended the BIPT for its achievements since the Preliminary Design Review in December 2011 which were "beyond the expectation of the panel." He added: "We have singled out the continuity and benefit of the work done by the ITER Organization and the Domestic Agencies within the BIPT framework with a sharing of risk and information among all stakeholders."
The panel nevertheless pointed out some remaining issues, including a few challenging issues that need to be addressed at the project level. But thanks to the excellent quality of work performed by the BIPT, the ITER blanket design can today be called "approved." The BIPT can now turn its focus to addressing the feedback received at the Final Design Review, applying the final touches to the design, and preparing for the Procurement Arrangements, where fabrication is handed over to the Domestic Agencies, starting at the end of 2013.
 
Source: ITER.org
 

EFDA bolt tighteningNaka, Japan: Clutching 2.5 metre long spanners, three teams of dignitaries from Europe and Japan simultaneously tighten bolts on the cryostat base of JT60 Super-Advanced, thereby marking a significant milestone – this major component for the Japanese tokamak was designed and manufactured in Spain.

The base is a 250-ton structure made of low-cobalt stainless steel that will support the complete tokamak. Together with an upper section the base will form a vacuum enclosure around the vacuum vessel and coils, allowing them to be cooled to low temperatures required by JT60-SA’s superconducting coils.

“Every project brings to you some new challenges.” says Joaquin Sanchez, head of research unit at CIEMAT. “On the one side, the need adapt the structure to the existing support basis at the JT60 building, which consists of two concentric rings. On the other side we have to guarantee the geometric stability of the upper part in order to preserve the vacuum tightness of the cryostat. This second requirement was a problem due to the fact that the upper ring of the base has to be in contact with elements at different  temperatures: the TF coil supports, and the vacuum vessel supports.”  However CIEMAT’s team of mechanical engineers was equal to the task, says Dr Sanchez: “We have been working on mechanical analysis & design problems for ITER and DEMO for a long time.”

The cryostat base was completed under the Broader Approach agreement between Japan and Europe. It was constructed by the company IDESA, located in Aviles, in the North of Spain, taking approximately 20 months.

 

Source: EFDA

F4E ilo polandThe business opportunities stemming from big science projects and the potential contribution of companies with their skills and expertise led Sylwia Wójtowicz, Poland’s Industrial Liaison Officer (ILO), to organise a one day seminar at Wroclaw Technology Park in order to showcase the ITER project together with the European Spallation Source. This was the second awareness day organised in the last three years and it came at the right time. Europe’s ITER procurement strategy has been outlined and contactors are actively looking for suppliers at different levels. The event managed to attract the interest of 30 representatives coming from the fields of services, cabling, IT and offered them information about the upcoming Calls for tender.

The plenary session opened with a presentation from Professor Maciej Chorowski, who highlighted the benefits that large scientific collaborations can yield to the economy and its operators. In this context, the ITER project was described as a true opportunity for fast track learning in new niche technologies with clear financial benefits in the long term. Anthony Courtial, representing F4E’s “Market policies, Analysis and Reporting” team, explained Europe’s contribution to ITER and elaborated on the different procurement packages that were of interest to the audience.

An online guided tour of the Industry and Associations portal was given to all participants focussing mainly on how to register and how to search for other business partners. One of the novelties of the seminar was a session called “Meet the company”, during which Polish companies presented to F4E their area of competence and capabilities in order to explore their potential contribution. The seminar concluded with meetings between different Polish companies exchanging contacts and understanding how they could complement each other’s skills.

To find out more about how your company could get involved in the ITER project, contact your Industrial Liaison Officer and keep checking the F4E website and theIndustry and Associations portal for any updates.

 

Source: F4E

F4E bullAs of 9 April 2013 GÉANT, the world’s leading high-speed research and education network managed and operated by DANTE in Cambridge, UK, will be providing data links to the International Fusion Energy Research Centre (IFERC), in Rokkasho, Japan. IFERC hosts the Helios supercomputer, a system with a compute power exceeding 1 PFlops and attached to a storage capacity of 50 PB. The Helios supercomputer is provided and operated by the French Alternative Energies and Atomic Energy Commission (CEA), France and is a Fusion for Energy (F4E) resource.

GÉANT is supplying a 10 Gbps (10 Gigabits per second) link to connect Helios with scientists involved in ITER and DEMO, the demonstration fusion reactor which is considered the follow-on project of ITER.
It is hoped, after the first fusion plasmas of ITER in Cadarache, France, planned for 2020 and beyond, that DEMO, an industrial demonstration fusion reactor, will lead to full-scale fusion energy reaching the commercial market in the second half of the century.

Massive data sets
HELIOS is producing vast amounts of data, which need to be shared with scientists all over the world. Via the Japanese National Research and Education Network (NREN) SINET, IFERC is connected to the pan-European GÉANT network, and to all European NRENs, like RENATER, DFN, SWITCH, JANET and many others), supporting the research activities for fusion in Europe. 
The GEANT-provided link is a 10Gbps connection between Geneva and Washington, matching the 10Gbps link between Japan and Washington provided by SINET. It will enable researchers in Europe to access this dedicated supercomputer in Japan. It may eventually be used to complement also the network resources allocated to other large scale projects, such as the CERN LHC experiment.

Roberto Sabatino Business Solutions consultant says: “The combination of major new scientific projects like IFERC and the use of supercomputers like Helios is creating an explosion of data for which we need to be ready. The provision of a 10Gbps link is a first and crucial step to support the data networking needs in the global search for cleaner, sustainable energy and to assist scientists in their ground-breaking work.”

Transporting high-volumes of traffic
Together with ever-growing data sets, greater collaboration in areas such as energy and genetics is driving a growing demand to access shared central databases of information across research disciplines, exponentially increasing network traffic. In the past, the most practical method for transferring bulk data from geographically dispersed clusters and end users was to physically ship disks by courier. With high speed networks such as GÉANT, data from many different sources can quickly be shared and analysed leading to accelerated results.

Europe’s vision for - sustainable energy
The ITER project is funded by and run by seven parties – Europe (contributing 45% of the cost), India, Japan, China, Russia, South Korea and the US. DEMO studies are carried out by individual ITER members, and in the case of Japan and Europe, jointly in the IFERC, in the framework of the Broader Approach Agreement. The investment in fusion research is in line with the EU’s focus for Horizon 2020 to find new and convincing solutions to the societal challenge of secure, clean and efficient energy. GÉANT is seen as an essential component in driving European ICT and for Europe to remain competitive in dealing with society’s grand challenges.

Susana Clement Lorenzo, F4E Group Leader for IFERC says: “Helios users are running codes ranging from fundamental physics in hot ITER plasmas to technology and engineering calculations so as to build components in very challenging environments as expected in DEMO. Supercomputers are crucial in solving these complex problems and good data communication channels such as the high-speed GÉANT network can provide the essential links to help scientists all over the world to analyse their findings. Ultimately, all these initiatives will bring us a step closer to fusion as a potential energy source.”

Big science reliant on high-speed networks
IFERC joins many other big science projects supported by GÉANT which are changing the way the world collaborates. Examples include CERN’s Large Hadron Collider and global projects addressing climate change, medical diagnosis, bioinformatics and deep space research.
To see a short clip on the Helios supercomputer click here
To see a short clip on GÉANT click here

 

Source: F4E

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Research projects carried out at the IPPLM are funded by the Polish Ministry of Education and Science, the National Science Centre and by the European Commission within the framework of EUROfusion Consortium under grant agreement No 101052200. Financial support comes also from the International Atomic Energy Agency, European Space Agency and LaserLab Consortium as well as from the Fusion for Energy Agency.

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