Sitting in his cabin 80 metres above the ground, Alex Dumonteil enjoys a most spectacular view. To the north, on a clear day, he can see as far as the Alpine ridge covered in eternal snow; to the south he has a clear view of the Sainte Victoire—the "mountain" that inspired Cézanne, Renoir, Kandinsky and several other art luminaries from the past two centuries. Although he is well aware of the landscape's artistic references, Alex doesn't dwell on them. He has a job to do, and it is one that requires his constant attention.   Alex is one of eighteen crane operators on the ITER worksite. One glance to the control screen, another toward the crane hook visible through the glass floor of his cabin, the right hand on a joystick ... he spends eight hours a day lifting construction material and equipment and positioning the loads with utmost precision wherever they are needed.   Last week, Alex opened his cabin to Newsline, providing a unique opportunity to see the ITER worksite through the eyes of a crane operator.    

Just one year ago, on 11 June 2018, the world's largest negative ion source was inaugurated at the ITER Neutral Beam Test Facility with the ignition of a brief plasma in the ion source. In the twelve months of experimentation since, scientists at SPIDER have been stepping up the testbed's power in increments, integrating additional components, and adjusting the complex system of controls. Late May, the SPIDER team celebrated the acceleration—for the first time—of a beam of ions. At Consorzio RFX in Padua, Italy, ITER neutral beam heating technology will be tested on two testbeds. The first to come on line, SPIDER, is an ITER-scale negative ion source designed to demonstrate all ITER source requirements; the second (under construction now) is MITICA—a full-size prototype of ITER's heating neutral beam injector.   The components designed for the testbeds are the same components that ITER will be using on its heating neutral beams in ITER, which will allow the neutral beam teams to acquire valuable information about neutral beam operation.   For SPIDER, operation began on 11 June 2018—the moment the ITER Director-General pressed down on the button that triggered the ignition of a hydrogen plasma in the ion source for the first time, lighting up the SPIDER vessel for several seconds.   During the following months, researchers focused on the optimization and the careful control of similar plasmas, in an attempt to maximize the transfer of power to the ionized gas through four radiofrequency generators. The combined use of eight antennas—connected to the generators in pairs—has allowed the team to increase the power transmitted to the plasma up to 320 kW, about 10 times more than the power reached during the inaugural plasma. This result was achieved thanks to the progressive improvement of the gas pressure profile, a more detailed understanding over time of the behaviour of the powerful radiofrequency generators, and improvements in the complex control system.   Later, the focus was moved on the SPIDER extraction and acceleration system. This is constituted by a set of three gridded electrodes (grids) featuring 1280 apertures each, from which the negatively charged particles generated inside the plasma are extracted and accelerated via an increasing potential difference applied on the grids.   In November 2018, the second grid—the extraction grid power supply (EGPS)—was integrated into the plant. From that point, large current of particles (mainly electrons) could be extracted from the plasma and accelerated to few kilovolts. In parallel, the teams worked to verify the capability of the system to hold the high voltage without any breakdowns and installed specialized diagnostic tools including the STRIKE calorimeter, several spectroscopy lines of sight and CCD (charge coupled device) detectors for visible light.   Finally, on 24 May, the third and last electrode of the acceleration system was set at a potential of 30 kV with respect to the second one, resulting in the formation of a fast negative hydrogen ion beam (see figure 1).   The achievement of the first hydrogen beam was celebrated by a commemorative strip by well-known cartoonist Stefano Intini. This result was welcomed with great satisfaction by researchers from Consorzio RFX and the ITER Organization. While sustaining the plasma is an important part of SPIDER operation, the beam is the component that will allow researchers to demonstrate that the requirements of ITER—in terms of quantity of ions (60 A of current resulting in a 6 MW beam) and electrons, and in terms of uniformity—can be met by the technology. Although the characteristics of the first beam at SPIDER are far from satisfying such stringent parameters, the importance of this early achievement consists in demonstrating that all the complex plants that control the source and the particle accelerator can be synergistically operated together.    The acceleration of the beam, in particular, confirms the perfect integration of the high voltage power supplies, procured by the Indian Domestic Agency, within the complex electrical system of SPIDER, an authentic masterpiece of electrical engineering.   The next weeks will be devoted to an initial investigation of properties of the first low-power beam and to a thorough characterization of the source. The integration of a final component—the caesium evaporators—will allow the generation of a larger amount of negative ions on SPIDER and higher beam performances.   The race to generate a beam of neutrals carrying 16 MW of power (required for each of the ITER neutral beam injectors) has officially started.   For further reading on the development of negative-ion-based neutral beam injection, click here.

The 18 upper ports of the ITER vacuum vessel are procured by Russia, manufactured in Germany, and mounted (in part) on the vessel sectors by contractors in Italy and Korea. Another example of how ITER would not be taking shape without globe-spanning collaboration. On a cold night in December 2018, upper port stub extension #10 left the factory of MAN Energy Solutions in Deggendorf, Germany, on the back of a transport truck for a several-day drive to Italy.   It was an inaugural voyage—over the next two years, the Russian Domestic Agency will be shipping four other port stub extensions to European Domestic Agency contractors in Italy to be welded onto vacuum vessel sectors before they are shipped to ITER.   The vehicle was blocked unexpectedly in Austria for nearly one month by heavy snow, but all ended well: the component was delivered in January and four other expeditions to Italy—less eventful we hope—are planned before the end of the year. Two upper port stub extensions—including the first production unit #12—have also been successfully transported by sea to Hyundai Heavy Industries in Korea and two others are expected. Procured by Russia, built in Germany from material sourced in Europe, welded to the vacuum vessel sectors in Korea or Europe ... the upper ports are a very international effort. Fabrication began in 2014. Four ITER Domestic Agencies are participating in the fabrication of the ITER vacuum vessel, making it a very international venture: Korea (four main sectors, equatorial ports, lower ports, gravity supports); Europe (five main sectors); India (in-wall shielding); and Russia (upper ports). Spaced in neat rows around the torus-shaped vacuum vessel at upper, equatorial and lower levels are 44 openings, or "ports" with a variety of service functions. From inside the plasma chamber, these access windows resemble the porthole of an airplane, only larger and with a variety of rectangular or trapezoidal shapes. From outside the vessel, the openings are completely hidden behind stub extensions and splice plates, connecting ducts and port stubs—everything needed to create a corridor of connection between the exterior wall of the vacuum vessel and the cryostat approximately six metres away. "Ports" are the stainless steel structures that extend out from each opening in the vacuum vessel, creating corridors of access to the machine for maintenance, diagnostics, or heating, fuelling, and vacuum pumping systems. They are made of the same ITER-grade austenitic steel as the main sectors and are an integral part of the vacuum vessel confinement and safety boundary. Like the vacuum vessel sectors, the ports are Safety Important Class components whose manufacturing requires strict quality assurance and close adherence to the nuclear code and regulations. Compliance to safety requirements at all fabrication stages is controlled by the Agreed Notified Body¹ (ANB Vinçotte, Belgium). The ports will be manufactured and installed in two phases—the 3- to 7-metre-long port stub extensions will be shipped to sector manufacturers and welded directly onto the vacuum vessel sectors, while the second-phase port extensions will be delivered directly to the ITER site and installed after the magnets in the Tokamak assembly pit. In Russia, the procurement of the 18 upper ports has been underway under the responsibility of main contractor NIIEFA (the Efremov Institute) since the signature of the Procurement Arrangement in 2009. NIIEFA has extensive experience in ITER standards and requirements, having led and coordinated R&D work undertaken by Russian laboratories for the modelling of high-vacuum and high-pressure components, in-vessel plasma-facing components, and the ITER divertor. In advance of or in parallel to the manufacturing activities, which were launched in 2014, ITER Russia has developed quality assurance documents and had them agreed by the ITER Organization, completed drawings, procured material (over 1,000 tonnes of austenite steel procured in Europe), selected the primary manufacturing contractor (2012), certified welding procedures, and qualified welding and non-destructive testing personnel in accordance with French nuclear regulations. For the fabrication of upper port stub extension #12, more than 250 procedures/documents were prepared by the Russian Domestic Agency and its suppliers. And there is more: at the completion of each component, factory acceptance tests are carried out by MAN Energy Solutions, with ITER Russia and ITER Organization observers, followed by site acceptance tests in Korea and Europe. "Being part of the worldwide team to realize ITER has been a challenge as well as an opportunity," says Thomas Schiller, head of Energy & Physics at MAN Energy Solutions. "Engineering and manufacturing such a safety-important component, given the quality and the quantity demanded, has opened a new chapter for MAN ES Deggendorf." ¹An Agreed Notified Body (ANB) is a private company authorized by the French Nuclear Regulator ASN to assess the conformity of components in the pressure equipment category (ESPN).

The job is done and the effect is spectacular. At the deepest basement level (B2) of the Tokamak Building, the floors, walls, and ceilings are now perfectly white. Sandblasting these vast surfaces prior to applying several layers of thick nuclear paint required more than 112 tonnes of abrasive material. In six months of painting, 30 tonnes of resin, primer and paint along with countless brushes and rolls were consumed.   Level B2 accounts for only one-sixth of the total surfaces to be painted in the Tokamak Building, not counting the central Tokamak Pit, which is a mammoth job in itself.   Last week, personnel from ITER Organization; the European Domestic Agency, Fusion for Energy; architect-engineer ENGAGE; and contractor Prezioso (specialized in the painting of nuclear buildings) did a final inspection check. With a few touch ups here and there, the job was considered done and well done.

In Hefei, China, a 400-tonne ring magnet procured by the European Domestic Agency is entering the final phase of production—resin impregnation. In just over one month, the component will be ready for packing and shipment to the ITER site.   Six years after a collaboration agreement was signed between the European Domestic Agency Fusion for Energy, responsible for procuring the component, and supplier ASIPP (the Institute of Plasma Physics/Chinese Academy of Sciences), ITER's sixth poloidal field coil, PF6, is being prepped for final coil impregnation.   PF6 is the second smallest of the ITER ring magnets in terms of diameter (10 metres), but the heaviest due to a higher number of stacked pancakes (nine instead of six or eight), a greater number of coil turns (twice as many as PF1) and exceptionally heavy clamps.   This last major production step ensures that the complete stack of nine double pancakes is electrically insulated and creates a rigid assembly. Following vacuum pressure impregnation and the completion of piping and instrumentation, the coil will be tested and packed for shipment.   Some of the external components of the coil—joint and clamps—are wrapped by ASIPP technicians before vacuum pressure impregnation. Fusion for Energy and ASIPP teams have collaborated closely throughout the multiyear fabrication process, from qualification activities back in 2016 and 2017, through pancake winding and pancake impregnation. When it reaches the ITER site, the completed component will be delivered for cold testing to the European Poloidal Field Coils Winding Facility.   In the assembly schedule of the ITER device, PF6 will be the first of the six poloidal field coils to be installed, lowered by overhead crane into the "dish" of the cryostat base to its position under the vacuum vessel. A ceremony for component completion is planned on 18 July at ASIPP. Click here to see a report on the Fusion for Energy website.

Superconductivity is a miracle of physics: when cooled down to temperatures close to absolute zero, certain alloys, or compounds, cease to oppose resistance to the passage of electricity. In electromagnets made of superconducting coils like ITER's, electrical consumption drops to zero and, as an added advantage, no heat is generated inside the magnets. Magnet cooling, however, requires a vast quantity of energy. Cooling fluids must be circulated through the entire length of the superconducting coils which, at ITER, means maintaining a forced flow of 25 tonnes of liquid helium at 4 K (minus 269 °C) throughout approximately 180 kilometres (and 10,000 tonnes) of conductor. For many years, research worldwide has struggled to develop materials that would transition to the superconducting state at less frigid temperatures—so-called "high-temperature" superconductors. Used in electromagnets, these "high-temperature" superconductors would allow the production of more powerful magnetic fields, passing the present limitation of low-temperature conductors (At its maximum in the centre of the ITER central solenoid, the magnetic field has an intensity of 13 Tesla.) The National High Magnetic Field Laboratory in Tallahassee, Florida, recently announced an important breakthrough in the quest for "high-temperature" superconductors: the manufacturing and testing of a half-pint "little big coil" that operated inside the bore of large outer copper coil in a background field of approximately 30 T, itself generating an additional 14.4 T, thus generating a combined record magnetic field of 45.5 Tesla in its (small) bore. This experiment demonstrated the capability of high temperature superconductors to operate in very high magnetic fields under large stresses. This could open the way to a new generation of magnets for biomedical research and fusion reactors.  More information on the National High Magnetic Field Laboratory website and in this month's issue of Nature.

Every two years, the Festival de Théorie aims to promote interactions between PhD students, postdocs and young scientists in fusion plasma physics and related fields including astrophysics, fluid mechanics and geophysics. Many of the principles governing the turbulence and magneto-hydrodynamic phenomena observed in fusion plasmas are similar to those found in naturally occurring astrophysical plasmas in the Sun. Fluid mechanics and planetary atmospheric physics also share common threads, reporting observations that often reflect the experimental measurements taken in tokamaks. This is where the Festival de Théorie comes in, fostering cross-disciplinary collaboration and providing an invaluable forum for tackling some of the key issues posed by ITER. The theme selected this year is: Phase Dynamics. The 2019 program is organized around four weeks of study and research in collaboration with a core group of prominent scientists. Participants begin with two weeks of seminars and lectures, followed by research projects in weeks 3 and 4 on topics spanning plasma physics, fluid dynamics, astrophysics, and applied mathematics. The 10th edition of the Festival de Théorie will take place in Aix-en-Provence, France, from 1 to 26 July 2019. Registration is open now.