Mechanical pumps alone cannot achieve the vacuum quality that is indispensable to producing the ITER plasmas (that is, one hundred billionth the density of the atmosphere). Once mechanical pumps have evacuated most of the air molecules and impurities from inside the vacuum vessel, another type of pumping device is needed to finalize the job and trap the remaining particles. The laws of physics provide a solution—cold. Molecules, atoms, particles can all be captured by cold and the more intense the cold, the more irresistible its power of attraction. A surface cooled to a very low temperature will eventually "grab" almost every particle it comes into contact with.   This is the principle upon which the cryopumps are based. Operating with helium at 4.5 K (minus 268.5 °C) the six ITER torus cryopumps, among the world's highest speed pumping devices, will create the high vacuum inside the vessel prior to a plasma shot and pump all exhaust gases during the plasma. They will also extract the helium ash from the fusion reaction along with the "unburned" deuterium and tritium nuclei.   More than 15 high-technology companies have been involved in the manufacturing of the first full-size pre-production torus cryopump. Now in their final stages, the different assemblies that form the pre-production cryopump are taking shape in the factories of the consortium formed by the German firm Research Instruments and the French company Alsyom. (The ITER cryopumps are part of Europe's contribution to ITER.)   The 8-tonne, 3-metre pre-production torus cryopump will now travel to Germany, where components such as cryogenic surfaces, charcoal-coated panels and protective thermal screens will be installed. Last week, members of the ITER Vacuum Section travelled to Tarbes, in southwestern France, where Alsyom had just finalized the casing for the pump. The team wanted to make sure that there were no issues before the 8-tonne, 3-metre cylinder is sent to Germany to be equipped with its internal cryogenic circuits.   "The torus cryopumps are large, complex, high-precision components that will be exposed to huge temperature gradients in a very punishing environment," says Section Leader Robert Pearce. "Integrated in the pumps is the world's largest all-metal high-vacuum valve and it was an extraordinary accomplishment that our contractors were able to achieve 80-micron tolerances over such a large component with heavy welding."   The pre-production torus cryopump will now travel to Germany, where specialists at Research Instruments will install its inner components—cryogenic surfaces, charcoal-coated panels and protective thermal screens. Once finalized and leak-tested, it will be characterized on a test facility and is likely to be the first pump to be installed on ITER. 

The AMW consortium (Ansaldo Nucleare S.p.A, Mangiarotti, Walter Tosto) was chosen in 2010 by the European Domestic Agency to manufacture Europe's contribution to the ITER vacuum vessel. The photos below document progress at Walter Tosto, where activities are underway to manufacture the different elements that make up a full vacuum vessel sector. The ITER vacuum vessel will be twice as big and sixteen times as heavy as the largest tokamak in operation today. Its double-wall structure is designed to provide a high quality vacuum for the plasma as well as the first confinement barrier for tritium, forming an important part of safety of the ITER device.   The complex doughnut-shape container is formed from nine sectors that are welded together. Four segments go into the manufacturing of a sector (inboard, upper, equatorial and lower). Seen from above, one sub-assembly for upper poloidal segment PS2 under fit-up last autumn. The sub-assembly is made of 2 inner shells, 60-millimetre formed plates, 3 poloidal ribs, 16 flexible housings and 4 inter-modular keys. Now, the sub-assembly has been fully welded and the repair of some localized defects is ending. Technicians at Walter Tosto are carrying out the cold and hot press forming activities for all the segments of the AMW consortium and the full manufacturing of two of the segments—the upper (PS2) and equatorial (PS3) poloidal segments. Each of these in turn is formed from several sub-segments. When completed, each vacuum vessel sector will be 13 metres high, 6.5 metres wide, 35-85 thick (double wall) and weigh about 450 tonnes.   For more about the ITER vacuum vessel, click here.

Visits at ITER are one of the best ways to establish, and maintain, a close relationship with the public. School children, university students, industrial representatives, members of the general public and government officials—close to 15,000 visitors in all—came on site in 2016, bringing the cumulative number of visitors since 2007 to 114,927. Visits can be divided into three categories.  Educative visits for school children and universities (46 percent), with educational workshops on energy and ITER site biodiversity, are managed by Agence ITER France—an agency of the neighbouring Commissariat à l'énergie atomique (CEA). The rest—visits for the public and the media, as well as VIP visits—are organized by the ITER Organization.   How does it feel to step into the heart of the most ambitious scientific project of the world?  A visit to ITER generally includes a presentation on the project at the Visitor Centre and a drive on the construction platform.   When ITER first opened its doors to the public in 2007, site preparatory works were underway. Those works consisted mainly in the clearing and the levelling of a vast platform to house the 39 buildings and technical areas of the ITER installation.   Year after year, as construction progressed, the platform had more and more to offer to the eyes of visitors. The Poloidal Field Coils Winding Facility and the early phases of the electrical switchyard in 2011 ... a new Headquarters building for the ITER Organization in 2013 ... and of course, the foundations of the spectacular Tokamak Complex.   More recently, the Cryostat Workshop was completed in 2014, followed by the huge Assembly Building in 2015.    Now, with 1,500 workers active on site and construction projects mushrooming in every corner, what used to be a vast and empty platform has become one of the largest construction sites in Europe.   Definitely worth a visit! If you are interested in a site visit, click on this link to access to our new on-line booking system.

Ozone is one of the most efficient disinfectants—in ITER, it will be injected into the heat rejection system to limit the growth of bacteria and other living organisms.   A molecule composed of three oxygen atoms, ozone will be produced on site from the oxygen present in the atmosphere. It will be obtained by circulating a flow of oxygen-enriched gas (90 percent) through a system of glass tubes and high-voltage electrodes.   The installation, housed in three large containers located at the south edge of the cooling basins, comprises four ozone generators. Normally, only three of these "ozonators" will be in operation at a given time, each producing an average of 4 kilograms per hour.   As ozone rapidly dissipates in water, the ozonation system will have to run continuously ... although full capacity will only be required during plasma operation.   Part of India's contribution to the project, the fully equipped containers left the port of Hazira on 27 January and are expected at Fos harbour on 19/20 February.

Please see the original article on the European Domestic Agency website.Click here for more on the tritium breeding program at ITER. European contractors have begun testing a candidate material for fusion reactors—a low-activation steel known as EUROFER97 that offers good resistance to high heat flux and neutron irradiation. The European Domestic Agency has chosen EUROFER97 for the two Test Blanket Modules that it will test in ITER—the Helium-Cooled Pebble-Bed (HCPB) and the Helium-Cooled Lead Lithium (HCLL). By testing tritium concepts on ITER in a real fusion environment, scientists have a unique opportunity to explore the most promising techniques for tritium breeding that will be a critical technology for next-phase fusion devices. Based on a contract signed with Studsvik (Sweden) in 2015, a series of tests will be performed to learn more about the physical and mechanical properties of EUROFER97. With the help of Studsvik subcontractor NRG, testing has begun at the High Flux Reactor in Petten, the Netherlands, on samples of the material. By exposing the candidate steel to the same neutron radiation and temperature as in ITER the tests aim to demonstrate that EUROFER97 is sufficiently resistant. After each irradiation phase, the metal will be transported back to Studsvik for detailed technical analysis. Researchers will look particularly at the brittleness of the material after irradiation, the microscopic changes that have taken place, and the extent to which material strength is affected. Tests are expected to continue through early 2018.

Aix-Marseille University and the ITER Organization are pleased to announce the 9th ITER International School which will be held in Aix-en-Provence, France, from 20-24 March 2017. This school, held annually either near ITER or in one of the ITER Members, aims at preparing young researchers to tackle the challenges of magnetic fusion devices, and spreading the global knowledge required for a timely and competent exploitation of the ITER physics potential. This year, the summer school will cover the physics of disruptions and control—one of the key issues for the ITER reactor and burning plasmas in general. Lectures and specialized seminars will cover current developments in theory and experiments, but are also intended to give the basics of the field. Poster sessions allowing participants to show their work are planned. The 2017 ITER school will be a good opportunity for reviewing the recent progresses in this field and promoting the interaction between different branches of plasma physics, computational physics and applied mathematics. The course is open to PhD students and postdocs aiming to work in the field of magnetically confined fusion, as well as Master students in physics or engineering. Registration ends on 7 March 2017. For more information, please visit the website. Editor's note: The first ITER school was organized in July 2007 in Aix-en-Provence, France, and was focused on turbulent transport in fusion plasmas. Five different editions have followed, focused on different subjects: in 2008 in Fukuoka, Japan (magnetic confinement); in 2009 in Aix-en-Provence, France (plasma-surface interaction); in 2010 in Austin, Texas (Magneto-Hydro-Dynamics); in 2011 in Aix-en-Provence (energetic particles); in 2012 in Ahmedabad, India (radio-frequency heating), in 2014 in Aix-en-Provence (high performance computing in fusion science); and in 2016 in Hefei, China (transport and pedestal physics in tokamaks).