The State visit by French President Emmanuel Macron to Washington dominated the news this week. The main media interest ranged from the Iran nuclear deal and the Paris agreement to presidential handshakes and the symbolism of dinnerware. But under the radar, another important issue was on the Trump-Macron agenda: US support for an ITER Project that is on track for success. France is not only the host country of the ITER Project; it also funds about 16 percent of the overall project cost—more than any other single nation. This means France is heavily vested in ITER's well being. Even more importantly, as he emphasized during his address to the US Congress, the French President places high value on scientific discovery and technological innovation. He is a strong vocal advocate for a clean energy future—underscoring the value of ITER.   As a clear signal of ITER's priority, President Macron asked ITER Director-General Bernard Bigot to accompany his presidential delegation to Washington. On Tuesday, in his speech at the French embassy, President Macron singled out ITER as an example of how large cooperative projects and common initiatives in the field of science can be used to build and strengthen bilateral and multilateral relationships among the ITER Members. The ITER Director-General was asked to participate in meetings with President Trump and the US Congress, and built on these discussions in his interactions with Secretary Perry and other US officials.   The time was well spent; the discussions were fruitful. According to the ITER Director-General: "It was clear from President Trump and President Macron's statement that both countries remain committed to maintaining global leadership on nuclear energy, including advanced nuclear technology. In that context, they stated that the US and France will support the ITER program and related scientific cooperation projects."   This outcome, together with the recent positive actions by the US Congress related to ITER funding, is clearly a meaningful step forward.  

On the floor of the vast amphitheatre that will accommodate the ITER machine, one of the most complex and most strategic structures of the Tokamak Building is taking shape. Reminiscent of a spiked crown—not unlike the one atop the Statue of Liberty—the structure is designed to support the combined mass of the cryostat and Tokamak (25,000 tonnes) while transferring the forces and stresses generated during plasma operations to the ground.   Aptly enough, the structure sitting at the bottom of the Tokamak Pit is called ... a "crown."   Its principle is inspired by the "flying buttress"—an architectural solution that was implemented eight centuries ago to prevent a cathedral's walls from collapsing outward under the weight of its stone ceiling and slate roof.   In the long story of the design of the ITER buildings, the crown is a relative newcomer: up until 2012, the baseline solution to support the machine consisted of a circular arrangement of 18 sturdy steel columns.   However as models and simulations were refined, it became clear that the load transfer from the Tokamak's mass and movements to the floor of the Tokamak Complex (the B2 slab) was not totally satisfying.   Machine "up lift" from a potential vertical displacement event,  cryostat "shrinkage" from a possible ingress¹ cooling event  ... these potential events were of particular concern to safety experts.   Developing an alternate option to the columns led to a one-year collaborative effort involving several ITER departments, the European Domestic Agency responsible for building construction, and their architect engineer Engage.   Inspired by history but unique to ITER, the radial walls are the "spikes" of the crown that will support the combined mass of the cryostat and Tokamak (25,000 tonnes) while transferring the forces and stresses generated during plasma operations to the ground. Engage eventually suggested mobilizing the resistance capacity of the bioshield wall (3.2 metres thick at its base) and using it as an abutment for a set of 18 deeply imbedded radial walls—the "flying buttress" solution.   The full constructability of this innovative structure, both inspired by history and unique to ITER, needed to be demonstrated however. In October 2017, a full-scale mockup, three metres high, was erected on the ITER platform to answer the questions that even the most detailed 3D models couldn't.   Six months have passed. Down on the floor of the Tokamak Pit the steel reinforcement for about one-fourth of the crown has been set into place and—thanks partly to a recently-implemented night shift—work is progressing quickly on the remaining three-fourths.   Massive steel transition pieces, 3.5 tonnes each, have been placed atop every radial wall to optimize the transfer of loads to the ground. Lengths of thin red plastic piping are being inserted into the steel rebar to circulate cooling water during the concrete pouring phase; two kilometres of this piping will be required in all for the crown. Finally, workers are busy welding a thin "fire mesh" to the outer face of the walls to within millimetric tolerances. (See gallery below for details.)   "Everything we are implementing now has been tested and validated on the mockup: the rebar installation sequence, the concrete formulation and pouring procedures, the temperature monitoring, the cooling system arrangement and sequences ..." explains Armand Gjoklaj of the ITER Building & Civil Works Section.   And the mockup's mission is not over yet—the installation procedure for high-strength "top plates" still needs to be tested and validated. These 3.5-tonne elements will sit on top of the steel transition pieces to receive 18 semi-spherical "bearings."   The first concrete pour for the crown is scheduled in mid-May and the entire structure should be finalized by September. And as all surfaces of the nuclear buildings need to be clean and decontaminable, a huge paint job will follow on the bioshield inner walls, on the crown's radial walls and on the floor.   The concrete amphitheatre of today will turn into a polished jewel box, ready to accommodate one of the most extraordinary creations of the human mind: the ITER Tokamak.    ¹The liquid helium cooling circuits for the superconducting magnets pass through the cryostat. In case of a breach, the sudden drop in temperature would cause a "shrinking" of the cryostat.

The two quench tanks that were sitting in the holding area on the edge of the ITER premises near the car park moved onto the ITER platform today. A remotely handled self-propelled modular transporter with 18 independently manoeuvrable axles took one tank to its final destination just outside the cryoplant building. The second tank, already transferred onto the platform, will join its twin later this week.   With their dimensions of 35 metres in length and almost five metres in diameter, and weighing 163 tonnes each, the twin tanks are among the largest components of the cryoplant. They are integral parts of the cryogenic system, designed to hold helium from the Tokamak's magnetic system in case of a sudden loss of superconductivity (a quench).

On 13 April, the ENGAGE consortium celebrated its eight-year anniversary at ITER. The celebration itself was unique: hosted at the offices of La Provence, the daily regional newspaper published in Marseille. A backdrop of newsprint rolls, shining conveyer belts, and giant printing machines lent an industrial setting to the congratulations offered by ITER Director-General Bernard Bigot, Senior Construction Project Manager for the European Domestic Agency Laurent Schmieder, and members of the ENGAGE senior management team. Speeches were punctuated with photo and video histories depicting the evolution of the ITER worksite, dating back to 13 April 2010, "when it all began" for ENGAGE: the award of the architect-engineer contract by the European Domestic Agency to construct the vast bulk of the buildings, infrastructure and power supplies on the ITER worksite. Refreshments followed—including a cutaway view of the Tokamak Complex elegantly rendered in chocolate.   Best of all, a surprise awaited the guests. Midway through the festivities, the machines began to hum and the crowd began to migrate to the production centre. A truly "special edition" of La Provence rolled off the presses, a memento for each guest commemorating the event itself, complete with photos of the moment and the catchy headline: "All ENGAGED in Fusion."   Open the special issue of La Provence, featuring articles in English, Spanish and French here.   For a look back in ITER history, the original Newsline article on the ENGAGE contract—from 16 April 2010—can be read here.

A group of young fusion enthusiasts seems to be the first who managed to put the Sun in a box. In this case, though, the box is quite literal ... and contains a board game they invented to make learning about ITER easy and entertaining. What will the ITER Tokamak weigh? What is the function of the breeding blankets? And at what temperature does the fusion reaction take place? Players are meant to work in teams to advance in this ITER version of Trivial Pursuit by answering these kinds of questions. Just like with the original Trivial Pursuit, there are several categories of questions: design and technical aspects; thermonuclear physics; manufacturing and construction; safety, quality, security and regulations; project management; and general issues. Correctly answered questions are rewarded with small plastic tokens representing key structural components of the ITER machine. As the game progresses, players collect the components to assemble a small 3D-printed model. The team that first completes its mini tokamak wins the game. And along the way all players gain a basic understanding of nuclear fusion and the ITER Project. The board game was developed by a group of employees from Assystem, one of the companies in the consortium ENGAGE, the architect/engineer for ITER construction. Calling themselves Young Generation Fusion, they want to raise awareness about fusion energy and ITER by creating projects that attract the attention of a wide audience. In April, they had the chance to present ITER Director-General Bernard Bigot with a copy of "Sun in a Box." They also present their creations at trade fairs and conferences. --From left to right, Young Generation Fusioneers Eric Kruger, Clarisse Thouzeau, Guillaume Merriaux-Mansart and Gregory Thibault (Sebastien Lonjon and Camille Taberlet are not shown).