The last time a méchoui was served at ITER it was 18 April 2012 and the 493rd—and final—seismic pad had just been installed in the Tokamak Complex Seismic Pit.   A North-African tradition, méchoui, or roast lamb on a spit, was back on site last Thursday 18 September ... along with mussels and boiled squid ... to celebrate the recent completion of the Tokamak Complex basemat.   From those who had worked on the rebar arrangement to the workers who had poured the concrete, they were all present: staff from GTM, the company that led the construction consortium; designers from Engage; safety specialists from Apave; management support personnel from Energhia; and of course staff from the ITER Organization and the European Domestic Agency Fusion for Energy.   Julio Diaz, the general foreman for the GTM says that the work "... was quite challenging, beginning with the nature of the rock and the extreme density and complexity of the steel reinforcement and culminating in the delicate positioning of the embedded plates. But the job was done, and well done..." As whole lambs roasted slowly over the open fire, joy and pride could be read in the faces assembled around the tables. "Happy! I'm just happy," smiled Julio Diaz, a veteran construction worker and the general foreman for the GTM consortium. "I've been part of this adventure since the very first day in the summer of 2010. The work was quite challenging, beginning with the nature of the rock and the extreme density and complexity of the steel reinforcement and culminating in the delicate positioning of the embedded plates. But the job was done, and well done..."   This feeling of "mission accomplished" is shared by GTM's project director Thierry Lebeault. "What's particularly satisfying is the excellent result that we have achieved in terms of worker safety. I see two reasons for this good safety record: the high level of requirements from the building owner Fusion for Energy and our own commitment to safety and quality."   The méchoui offered by GTM isn't the end of the story. "There is still finishing work to be done on the slab that will keep us busy until the end of the year," says Diaz.   We can expect another méchoui  when civil works are completed on the Tokamak Complex Building.

US ITER researchers based at the Department of Energy's Oak Ridge National Laboratory (ORNL) are leading the development of a disruption mitigation system to reduce the effects of plasma disruptions on ITER. The US Domestic Agency for ITER signed a formal arrangement with the ITER Organization on 29 July for the work and during the week of 8 September the ITER Fuelling & Wall Conditioning Section leader, So Maruyama, paid a visit to Oak Ridge to assess US progress and plan for an upcoming design review of the ITER disruption mitigation technologies.   "I'm impressed," said Maruyama after his visit to the disruption mitigation and pellet injection team at Oak Ridge. "Only a year or two ago these were rough ideas. Now we have real prototypes that are functioning and being tested, such as the massive gas injection valve and the pellet selector."   "We have a very conservative and flexible approach to disruption mitigation on ITER," said Larry Baylor, a distinguished scientist in plasma technologies and applications at ORNL, "with different locations for material to be injected, different types of material, and different response times. We are also designing the system in a way that will allow for evolution of the mitigation technology."   The guide tube selector test unit prototype has now been installed at the ORNL pellet lab for testing. The unit is designed to guide pellets to specific locations in the plasma. Photo: US ITER/ORNL Two approaches have been developed to help control plasma disruptions: massive gas injection and shattered pellet injection. Both deliver material to the plasma within milliseconds. By injecting material into the plasma, ITER operators will be able to manage plasma energy in a way that lessens thermal loads and mechanical stresses on the plasma-facing components of the machine. The injected material can also inhibit the formation of runaway electrons, which occur when electrons are accelerated from the electric field in the plasma during a disruption.   "This is essential technology development for ITER," noted Maruyama. "Oak Ridge is the expert on the pellet injector and has a long history of contributions to other machines such as JET, DIII-D and LHD."   The development of technologies for ITER disruption mitigation benefits from physics input from around the world, including the ITER Organization, JET and Oak Ridge. The disruption mitigation design is also influenced by ITER experts in vacuum, tritium, cryogenics and port plug integration.   The next major step for disruption mitigation is a system-level design review in November. Maruyama notes that "this review will help us confirm where we are and what we've achieved, and help us try to narrow down options for the path forward."

Testing has ended on a full-scale, rectangular bellows prototype at the Swiss firm Kompaflex (kompaflex ag), successfully completing the last step in the bellows design. Eighty-five large, rectangular bellows will be used between the ITER vacuum vessel, the cryostat and the walls of the Tokamak Building themselves to isolate the ultra-high vacuum inside the cryostat from the building port cell environment, and to compensate relative movement that can occur during different operational regimes like baking of the vacuum vessel, or during seismic events. On 27 August, a 3.2 x 3.6 metre prototype of the upper port duct bellows successfully passed pressure stability tests. Even in the case of the largest required pressure of 0.6.bar across the bellows—only predictable elastic deformation of the bellows was caused and following pressure relief, the bellow convolutions returned to their initial position. Only at 1bar pressure across the bellows the first small plastic deformations of 2mm were detected, which showed significant design margin to the pressure requirements. The fatigue life test of the bellows was also successfully completed. Kompaflex has the capacity to produce a multi-ply rectangular construction of bellows without welding seams in the corner area, fulfilling ITER's requirement for very short building length, enormous movements in combination with a certain number of cycles, and low spring rates. A rectangular bellows with a very short convoluted length was tested for an axial movement range of 136 mm and the requested number of 500 cycles was fulfilled without any damage. After completion of the design work on the bellows end connections, the Final Design Review for the rectangular bellows is scheduled for April 2015. The signature of the Procurement Arrangement will follow.

By providing designers with a concrete, three-dimensional experience of the object under development, mockups play an important part in the design and configuration process of the ITER installation's components. Up to now, mockups have been produced by specialized companies using ITER Organization 3D files that contain component specifications. "In the mockup manufacturing process, the preparation of the 3D file represents the largest part of the work," explain Christophe Penot, designer, and Jérôme Ferréol of the Diagnostic Division support team.However, a 3D file does not translate automatically into a 3D mockup: the component's features are sometimes so intricate that the contracting company needs to make modifications to the file to ensure technical feasibility—modifications that have a strong impact on the final cost. "We realized that if we could test the feasibility of mockup manufacturing before sending the file to the contractor, we could save a significant amount of money." Last December, an investment of approximately EUR 1,000 was made in an off-the-shelf 3D printer. After a couple of months of operation, it has turned into a significant cost containment tool for ITER. The relatively cheap commercial 3D printer allows designers like Christophe to verify the feasibility of the 3D printing before the file is sent to the specialized company for actual mockup production. "If the file needs to be modified, we can do it in-house, which is much faster and less costly—especially if we have to do several mockups of the same component." In the 3D printing process, three-dimensional objects are created by laying down successive layers of melted material (plastic or metal, for example). Producing a plastic 3D mockup in-house doesn't cost a lot: a mockup of an ITER port plug (0.1 percent of its actual size) for instance costs about five euros in raw material and the hours the designer spends in finalizing the 3D file. The printing itself takes between one hour and a few days depending on the complexity of the component.And there's another important aspect to in-house 3D printing according to Christophe and Jérôme: "It is both rewarding and useful to have a physical rendition of an object that, up to then, was only virtual." The small 3D printer has been operational since June. A dozen small mockups have already been produced—upper and equatorial port plugs, a closure flange, an interspace support structure, etc.—and the machine shows no sign of tiring. "It just needs a bit of maintenance, no more or less than the regular printer that it is sitting next to." Click here to watch a short video clip of 3D printing at ITER.

The European Domestic Agency has awarded contracts for the fabrication of three full-size prototypes of the blanket first wall, an important next step in the qualification of the first wall panels that follows in the steps of the successful manufacturing of a 1:6-scale semi-prototype earlier this year. Contracts were signed with Atmostat (ALCEN group, France), AREVA (France), and a consortium made up of AMEC (UK), Iberdrola (Spain) and MIB (Spain). Each of these companies is to manufacture a full-size prototype of a blanket first wall panel, as well as carry out specific industrialization studies for series production and present a cost and schedule assessment. The choice of three companies was made by the European Domestic Agency to mitigate risk on these technically challenging components and preserve competition up to series production. Europe is responsible for procuring 215 normal heat flux first wall panels, while China and Russia are sharing the procurement of 225 enhanced heat flux panels. (A total of 440 first wall panels are needed for the ITER blanket.) These extremely high-tech components are made of 6- to 10-millimetre-thick beryllium tiles that are bonded with a copper alloy and 316L (N) stainless steel. More on the manufacturing process for first wall panels can be found in the original article on the European Domestic Agency website. Delivery of the full-scale prototypes is expected in early 2017.

On 8-9 September the final acceptance meeting was held for the Cryostat Workshop. This 5,500-square-metre building will be the theatre for the assembly of the four main cryostat sections from 54 smaller segments manufactured in India.   As the contractor chosen by the Indian Domestic Agency for the construction and assembly of the ITER cryostat, Larsen & Toubro Limited is also in charge of the on-site cryostat worksite. The company awarded the construction contract to the French company SPIE Batignolles TPCI, who began work just over a year ago, in June 2013.   "Larsen & Toubro (L&T) takes pride in having completed the temporary workshop before the contractual delivery date," a company statement read. "This was possible due to the positive and collaborative efforts by all of the teams involved: SPIE Batignolles TPCI, Danieli (crane contractor), Currie & Brown (engineering), Apave (health and safety protection), ITER India and the ITER Organization. Larsen & Toubro is thankful to all of these teams for their role in achieving this feat."

​The process of magnetic field line reconnection, in which the magnetic field lines in a plasma snap apart and violently reconnect, transforms magnetic field energy into particle energy. Little was known about this phenomenon that is known most prominently in the form of solar flares on the surface of the sun. The subsequent geomagnetic storms on earth have demonstrated how much energy can be released by magnetic reconnection. In the research conducted on the Magnetic Reconnection Experiment (MRX) at PPPL, scientists measured experimentally the amount of magnetic energy that turns into particle energy. They showed that reconnection converts about 50 percent of the magnetic energy in the plasma, with one-third of the conversion heating the electrons and two-thirds accelerating the ions. The findings also suggested the process by which the energy conversion occurs. According to the researchers, reconnection first propels and energizes the electrons, which creates an electrically charged field that becomes the primary energy source for the ions. Read more on the FuseNet and News at Princeton websites.

​A weird type of 'hybrid' star has been discovered nearly 40 years since it was first theorized — but until now has been curiously difficult to find. In 1975, renowned astrophysicists Kip Thorne, of the California Institute of Technology (Caltech) in Pasadena, Calif., and Anna Żytkow, of the University of Cambridge, UK, assembled a theory on how a large dying star could swallow its neutron star binary partner, thus becoming a very rare type of stellar hybrid, nicknamed a Thorne-Żytkow object (or TŻO). The neutron star — a dense husk of degenerate matter that was once a massive star long since gone supernova — would spiral into the red supergiant's core, interrupting normal fusion processes. Read more here. Access the scientific article here

​After a decade of construction, the Wendelstein 7-X experiment (W7-X) is now its commissioning phase. Work is underway to install plasma-facing components and some of the in-components of the diagnostics. A first, three-month operation period is planned in 2015. Find out all the detail of the first plasmas planned in the latest issue of the Wendelstein 7-X newsletter here.