At one end of the repair process, an automatic welding robot worth several hundred thousand euros—adapted and equipped for the specific task of metal filling and build-up. At the other end, standard ultra-fine-grain scratch pads anyone could buy at a local store. In between, a whole range of tools used to progressively correct the faulty sections of the interface areas (the “bevels”) of vacuum vessel sector #8—the most affected by dimensional non-conformities of the vacuum vessel sectors already delivered to ITER. Pass after pass, progressing at an average speed of 10 centimetres per minute, the fully mechanized welding machine¹ has now completed its task on one side of vacuum vessel sector #8. The mechanized process, however, represents only 25 percent of the total metal build-up required. For reasons of accessibility and flexibility, the remaining 75 percent must be done manually. Once metal build-up is done, the nominal geometry will not yet be achieved. Excess metal must be removed—first by manual grinding, then, after having performed different kinds of non-destructive tests (including visual, liquid penetrant, and ultrasound), by using machining tools working in parallel in different regions of the bevel. Although the machining tools are driven by computer digital control (Computer Aided Manufacturing, CAM) based on precise metrology and as-designed 3D models, the quality of the repair is deemed satisfactorily controlled only after a last series of “manual dressing” operations—first with a file, then with sandpaper, and eventually with scratch pads. Adapted and equipped for the specific task of metal filling and build-up, the welding robot has now completed its task on one side of vacuum vessel sector #8. The mechanized process, however, represents only 25 percent of the total metal build-up required. For reasons of accessibility and flexibility, the remaining 75 percent must be done manually. Three months after repair operations were launched on vacuum vessel sector #8, 90 percent of metal build-up and half of pre-machining tests and controls are now completed. Machining has just started with two tools; three others are scheduled to join in the coming weeks. The SIMIC team in charge of repairs expects to complete operations around Christmas time.However, this is only half of the required task. In its present position, lying like a stranded whale in the former Cryostat Workshop, vacuum vessel #8 presents only two of its four 30-metre-long, D-shaped bevels (the outer and inner shell bevels). In order to make the other side accessible for repair, the component will need to be “flipped”—a very short and simple word to describe the massive and delicate operation of handling, lifting and turning over a 440-tonne piece of steel.¹ Contrary to “automatic welding,” which is performed without welding operator intervention, mechanized welding allows operators to adjust welding parameters throughout operations.

ITER Director-General Pietro Barabaschi made stops in Mumbai and Hazira this month during a trip to India to visit with a key industrial partner. After stakeholder meetings in China and Russia earlier this fall, the ITER Director-General was in India in October. He visited the headquarters and one of the principal manufacturing sites of Larsen & Toubro, the industrial conglomerate that was responsible for the production of the 3,800-tonne ITER cryostat. In Mumbai, a Memorandum of Understanding was signed between the ITER Organization and Larsen & Toubro for technical collaboration, specifically in the area of advanced welding technology for ITER machine assembly (vacuum vessel ports, bellows...). "In previous contributions to ITER, Larsen & Toubro has demonstrated its reliability in high-tech manufacturing," stressed ITER Director-General Barabaschi  "This [Memorandum of Understanding] is vital to meeting the technology challenges of the ITER Project." At the Larsen & Toubro manufacturing facility in Hazira, Director-General Barabaschi is speaking with a worker while Anil Parab, Director and Senior Executive Vice President (left) and Anil Bhardwaj, Project Manager for the ITER Cryostat and Group Leader/Mechanical Engineering (right) look on. On his return to ITER, a digital contract was signed with Larsen & Toubro representatives for a contract titled "Port Positioning Alignment & Welding." Ports provide access inside the vacuum vessel for auxiliary plasma heating, diagnostics, vacuum pumping, and other needs at three levels (upper, equatorial, and lower). During the digital signature of the Contract for Port Positioning Alignment & Welding.

Five years and 40 specialists—that is what it took for European Domestic Agency contractors to completely cover the interior walls of the Tokamak Complex with several layers of specially formulated paint. With a structure the size of the ITER Tokamak Complex, the topline numbers usually stand out the most. Its total weight, for example (more than 400,000 tonnes). Or the amount of concrete required for its construction (100,000 cubic metres). But the scale of the building project can also be measured in the many smaller tasks that were required to prepare the Complex for the installation of equipment.  One example is the final painting of interior surfaces. In the Diagnostics Building, paint provides for cleanliness and a dust-free environment. In the Tritium and Tokamak buildings, it is an element of nuclear safety. In nuclear buildings, the coating on the floors, walls and ceilings must present a perfectly smooth surface in order to be decontaminated in case of an incident or accident.  The European Domestic Agency (Fusion for Energy, F4E)—which, as part of its commitments to the project, has built nearly all of the platform buildings and site infrastructure—assembled the team to coat 200,000 m² of walls with several coats of specially formulated white paint. Since 2019, approximately 40 specialists from Spanish company GDES, with support from Engage and EnergHIA, proceeded room by room and floor by floor, first sandblasting the walls to leave a texture without cracks or pores for proper adherence, then applying several coats.  The last job was completed in the Tritium Building earlier this month. Read the full report on the Fusion for Energy website.

The DIII-D tokamak team at General Atomics (San Diego, US) celebrated a big milestone this month—achieving, and passing, the 200,000th plasma shot since the device began operating in the mid-1980s.   DIII-D played an important role in providing data for the engineering design phase of ITER. DIII-D pioneered key fusion technology, including the use of beams of neutral particles for plasma heating and resonant magnetic perturbation (RMP) coils to suppress plasma instabilities called Edge Localized Modes (ELMs). DIII-D is currently exploring a wide range of scientific issues which will assist in optimizing ITER operation. These include the exploration of the effect that internal stabilization coils have on preventing energy bursts from the plasma edge, the development of high-power microwave transmission line components with low energy losses, and work on software for controlling the plasma and protecting the ITER machine. “While completing 200,000 shots is impressive in its own right, this achievement is far more than a mere number,” said Dr. Richard Buttery, Director of the DIII-D National Fusion Facility, in a press release issued on 24 October. “Those shots represent steady, important progress on the road to fusion energy. Each one is a challenge solved, a question answered, a career begun or progressed, or a new technology proven. In a very real sense, the history of DIII-D is a history of fusion energy research, and we are very excited for what we have planned for DIII-D in the future.” In recent years, researchers have used DIII-D to make several important advancements in fusion, including surpassing a theoretical limitation on plasma density (an operational requirement for nearly all fusion power plant designs) and creating the world’s most powerful fusion plasmas in novel configurations, according to the press release. "These experiments have significant implications for the design of future power plants and the associated costs related to building, operating, and maintaining them." "DIII-D has been continually upgraded throughout its history, expanding its capabilities to serve as a testbed for the development of fusion technologies and scientific understanding. It recently completed an eight-month facility upgrade that further strengthened its standing as one of the most flexible and capable fusion research facilities in the world. The research campaign now being pursued with the newly upgraded device will help close key gaps between current experiments, the first fusion pilot plants (FPPs), and future fusion reactors." See the full press release here.

Of the nine vacuum vessel sectors that will form the ITER tokamak’s toroidal plasma chamber, four are procured by Korea and five by Europe. Over the past four years, three Korean sectors have been delivered, and the fourth one is expected in a little more than one week. On Friday 25 October, the first European sector—vacuum vessel sector #5, manufactured in Italy—passed the gates of the ITER site. In Korea, a single contractor, Hyundai Heavy Industries, is responsible for the manufacturing process for Korean sectors in the world’s largest shipyard located in Ulsan, on the east coast of the peninsula. In Europe, the choice was made to distribute the fabrication of the component between different companies mainly located in Italy, but also in Spain and Germany—all operating within the AMW consortium (Ansaldo Nucleare, Westinghouse/Mangiarotti, Walter Tosto and subcontractors). The trailer negotiates a difficult 90-degree turn at the exit of a steel bridge spanning the canal that feeds a local power plant. The bridge was built in 2009 to accommodate the ultra-heavy ITER convoys. Whatever the organizational choices, the manufacturing process and the end product are similar. An ITER vacuum vessel sector is among the most imposing of all machine components. At close to 20 metres tall and weighing approximately 440 tonnes (600 tonnes when you count its cabin-like housing and frame), it is an exceptionally delicate load to transport. In the wee hours of Friday 25 October, vacuum vessel #5 reaches the ITER site. To the right of the parked trailer is the cocooned upper section of the ITER cryostat. (Photo DAHER) There are now four vacuum vessel sectors on site, and there will be five by early November 2024. One (sector #7) has re-entered the module assembly process in one of the tall standing tools in the Assembly Hall. Two others are in various stages of repair—sector #6 in the second tool and sector #8 in the former Cryostat Workshop (read article in this issue).

The plasma physics division of the American Physical Society (APS) held its 66th annual meeting from October 7-11 in Atlanta, Georgia (USA). This  venue  provided an ideal opportunity to inform the US fusion community about the proposed new ITER baseline and Research Plan and to engage them on scientific discussions to refine the Research Plan.  In addition, a town hall meeting was organized by the US Burning Plasma Organization to present progress in systems/components procured by the US Domestic Agency and to discuss how the US fusion community can most effectively support the new ITER baseline and Research Plan. The latter includes carrying out R&D on open physics and scenario integration issues for the new baseline (especially those related to the use of tungsten as first wall material) as well as training the scientific teams that will execute the Research Plan experimental program.  “It’s important for the US ITER project and international ITER project to keep the plasma physics community informed about progress and engage their expertise for planning ITER research,” said US ITER project director Kathy McCarthy. As a whole, the conference covered a wide range of plasma physics topics with plasma physics for nuclear fusion being the one that was most represented. In the sessions dedicated to nuclear fusion, progress in experiments, modelling and theory were presented as well as the design and construction of new fusion facilities both from the public and the public sectors. The overall scientific presentation on the new ITER baseline and Research Plan at this meeting was supported by four further presentations (2 oral and 2 poster) by ITER postdoctoral researchers.