Satellite cleanliness engineering will help protect the ITER tokamak from construction contamination. When the ITER vacuum team realized that the level of construction debris and concrete dust in the Tokamak Building meant key components were getting so dirty that the machine might never operate to specification, they turned to a surprising place for help: space. "A high level of cleanliness is required for the operation of a vacuum machine and this wasn't the case with our components," explains Liam Worth, the Vacuum Systems Project Leader at ITER. "We needed a solution and we saw parallels with aerospace because satellites need to be kept clean during manufacture, stay clean while awaiting launch, and remain operational once they are in space where they can no longer be accessed." In an ideal world, a fusion reactor would be assembled in a clean room to ensure nothing could contaminate the components and undermine or even disable the tokamak altogether. However, due to schedule constraints, the reality at ITER is much different and tokamak assembly is taking place while there is still construction ongoing. Future commercial fusion reactors will also likely be assembled in buildings prior to the completion of civil works, which means the cleanliness protocols established at ITER can serve as guidelines for the broader fusion industry. While the vacuum team at ITER was aware that the construction activities were creating pollution in the Tokamak Building, the extent of the problem only became clear when a mandatory cleanliness report was required after vacuum vessel sector #6 was brought into the pit in 2022. The report showed concrete dust contamination on pit surfaces, an abundance of metallic particles from milling known as "swarf." "We had traditional cleaning methods such as chemical wiping, but as assembly progresses, the complexity of the system means there will be areas we can't physically get to," says Liam. "We needed a technical and philosophical change to get people to understand that it was essential to establish the cleanliness from the start because it will be impossible to clean later." For help developing the new cleanliness protocols, the vacuum team turned to OHB, a German systems integration company specializing in the aerospace industry, particularly in the assembly and operation of satellites for a range of customers including the European Space Agency. Because OHB requires rigorous cleanliness engineering for its space operations, the company created an internal Cleanliness Competence Centre (C3). Starting with the target performance, the cleanliness experts break down acceptable contamination levels and then develop mitigation, avoidance, standard and emergency cleaning, and "stay clean" concepts. This cleanliness engineering approach is also provided to external clients such as semi-conductor facilities or hospitals seeking to reduce contamination that could lead to infection risk during surgery. As it happened, the senior expert for contamination control at OHB, Axel Müller, was a fusion enthusiast who studied plasma physics at the Technical University of Munich and even worked at the ASDEX Upgrade tokamak in Garching. Müller immediately saw how the engineering of space cleaning could be applied to ITER. "They are both one-off production projects, which means they are unique designs and you can't just apply existing standards," says Müller. "For satellites, we develop all the methods and tools we need to do the specific cleanliness job. We are developing a slightly larger system with ITER but it's the same concept: control the small parts and then scale up the standard." An example of construction contamination in the machine assembly arena: metallic particles on poloidal field coil #5. Müller saw two other important similarities between space and fusion. First, they both required international cooperation and a shared supply system where contracts were divided among the members of the project. When OHB was involved with cleanliness engineering for the European Space Agency, the supply chain was spread out across the European Union, just as the ITER supply chain is spread out around the world. This means cleaning protocols must be adjusted so the gaps in cleanliness resulting from different suppliers can be addressed when the components arrive on site. The second big commonality was the time scale involved in the two projects. Because tokamak assembly requires years, many components need to be kept clean for long periods before they can be installed and preserved, in situ, prior to machine operations. "Space is similar to ITER," says Müller. "You might build a satellite and then it sits for a while before launch, so you have to keep it clean on the ground." Towards the end of 2022, OHB and ITER started two cleanliness recovery projects together, both named after Crius, the Greek god of the constellations, to evoke the idea of different parts working together. With the CRIUS I project, OHB evaluated an approach to the in-situ cleaning and cleanliness verification operations of vessel sector modules installed in the pit. Then, CRIUS II established possible cleaning concepts and development plans for the implementation of prototypes for specific cleaning tools and protective textile covers for ITER components. Under the plans currently being devised for the CRIUS III phase of the cleanliness engineering project, a series of critical milestones in the cleanliness chain are being identified such as transport, acceptance of goods, or installation. A cleanliness compliance contract will be established for each milestone and both contractors and ITER personnel will have to sign off on cleanliness before moving ahead. For storage on site, OHB plans to adopt bespoke textile covers that are based on the protection used for satellites.  "We now have a reasonably well-developed concept for cleaning methodology," says Liam. "The next step is to develop this into a fully operational system and then go in and actually do the cleaning."

ITER Director-General Pietro Barabaschi made a diplomatic trip to China last week to represent the ITER Project at multiple high-level meetings. On Thursday 5 September, Director-General Barabaschi met with the Chinese Minister of Science and Technology YIN Hejun at the Ministry of Science and Technology (MOST) in Beijing. In addition to updates on the ITER Project and proposed Baseline, they evoked the importance of ITER to the goal of developing nuclear fusion, the long-term collaboration with China within the framework of ITER, and the ways bilateral scientific and technological exchanges might be deepened.  A visit to the Chinese Academy of Sciences (CAS), a long-time collaborator to the ITER Project. Photo: CAS Director-General Barabaschi's trip also took him to the Chinese Academy of Sciences (CAS) where, accompanied by ITER Deputy Director-General (Corporate) LUO Delong, he met with Vice President CHANG Jin and staff members. The Chinese Academy of Sciences has been highly implicated in research, development and procurement for ITER. Its Institute of Plasma Physics is home to the EAST tokamak; it is also building the Comprehensive Research Facility for Fusion Technology (CRAFT) a platform for developing and testing fusion reactor key components. Discussions centred on current and future collaboration in the fields of cutting-edge physics and new technology, and on the development of fusion talent. A large delegation welcomed Director-General Barabaschi and Deputy Director-General LUO Delong (sixth from right) at the China National Nuclear Corporation. Photo: CNNC Discussions on expanding collaboration continued at the China National Nuclear Corporation (CNNC), where Pietro Barabaschi and LUO Delong met with General Manager SHEN Yanfeng, ITER China Director WANG Min, staff and industrial contractors. See related press releases (in Chinese) from MOST , CAS, and CNNC.

The detrimental effects of plasma disruptions are a major concern for ITER and all next-generation fusion devices. Experts from all over the world met early this month at ITER headquarters to exchange the latest, state-of-the-art findings on the consequences of disruptions, on identifying reliable methods for disruption prediction and on finding strategies for their mitigation. The International Atomic Energy Agency (IAEA) fosters international collaboration and helps to close gaps in the physics and technology of nuclear fusion by organizing a series of conferences and technical meetings. The aim of the "Third Technical Meeting on Plasma Disruptions and their Mitigation" hosted by the ITER Organization from 3 to 6 September was to bring together experts from the IAEA's member states to exchange the latest understanding on consequences, prediction and avoidance, and mitigation. The preparation of the meeting was overshadowed by the sad loss of ITER physicist Michal Lehnen, who was the chair of the meeting's Programme Committee and the leader of the ITER Disruption Mitigation System Task Force since its creation in 2018.  Michael's pioneering work was mentioned in numerous presentations and tribute was paid to him in a dedicated talk by ITER's Richard Pitts, Experiments & Plasma Operation Section Leader. The large attendance of about sixty colleagues onsite and another twenty remote is a testimony to the importance of this research topic, to which Michael contributed significantly. The Programme Committee had compiled a dense agenda, with 7 invited, 28 oral and 19 poster presentations. Ample time was reserved in four discussion sessions to target specific questions, for example the improvement of models for electromagnetic load calculations, optimum material injection parameters for disruption mitigation, and the best strategies for developing predictors that are universally applicable across existing and future tokamaks. At the beginning of the meeting, members of the ITER Organization gave an update on the proposed ITER re-baseline, its implications on various aspects of disruptions, and an overview of the ITER disruption mitigation system (DMS) as it was presented at the final design review earlier this year. The packed ITER Council Room with Technical Meeting participants listening to the latest results on JOREK modelling for ITER. The sudden release of the plasma's stored thermal and magnetic energy and the induction of significant currents into vessel components can have severe operational consequences for large tokamaks such as ITER and other future nuclear fusion facilities. Efforts are ongoing to develop physics models for assessing expected thermal and electromagnetic loads during such events. These physics models are validated using existing data from dedicated experiments on present-day tokamaks or purposely built devices. One good example is the recent improvement in modelling of runaway electron formation and the potential for damage induced by the impact of these runaways on plasma-facing components during the disruption current quench phase. To protect machine components from excessive heat loads and electromagnetic forces and to ensure an effective execution of the Research Plan, ITER will install a disruption mitigation system based on shattered pellet injection technology. Over the last few years, the technology has advanced to a level that allows for reliable disruption mitigation and extensive experimental campaigns have been carried out on several tokamaks (see reports here and here for example) to support DMS final design and to prepare for its operation. To a significant extent, it has been the work performed within the Disruption Mitigation System Task Force which has driven the technology developments. The enormous amount of data and modelling helps to reduce the uncertainty in predicting the effectiveness of massive material injection for disruption mitigation. In parallel, alternative methods—particularly for runaway electron dissipation—are being studied. Disruption mitigation will only work if the occurrence of these events can be predicted reliably during a plasma pulse. This requires the use of real-time detection systems, which employ a large number of sensors to monitor the plasma state and stability limits. The last years have seen a strong step forward towards detectors of imminent disruptions that incorporate physics models executed in real-time and towards the application of machine learning methods. The high success rates of current disruption predictors, with several examples reported at the IAEA meeting, give confidence that a robust system will be available for ITER to implement an effective disruption avoidance scheme reasonably quickly once operation begins.

Russia continues to deliver in-kind components to the ITER project according to procurement arrangements signed with the ITER Organization. Some recent manufacturing news is highlighted below. As part of in-kind contributions to ITER, Russia is supplying switching equipment, busbars, energy-absorbing resistors and control racks for the power supply and protection of the ITER superconducting magnets. Following the successful final design review (FDR 3.0) for switching devices, the D.V. Efremov Institute of Electrophysical Apparatus (JSC "NIIEFA") has begun the serial production of related components and systems such as the fast energy discharge system, control and diagnostics systems, the protective short-circuit device and others. In additional news, completed elements for the busbar system, operational switching resistors, and switching devices will leave the Efremov in up to 15 trailers for delivery to the ITER construction site by the end of the year. This full-scale prototype of an enhanced heat flux first wall blanket panel (with beryllium armour tiles) was produced as part of a qualification program at the Efremov Institute. During high heat flux cyclic testing, the surface temperature of the tiles reached 650 °C (explaining the discoloration). The team has now begun a qualification program to validate tungsten as the blanket first wall armour material. Specialists from the Efremov are also actively collaborating with other ITER partners on the development of the first wall of the ITER blanket—a critical machine component that shields the steel vacuum vessel and superconducting toroidal field magnets from the heat and high-energy neutrons produced by fusion reactions. China and Russia are sharing the procurement of 225 enhanced heat flux first wall panels, designed for heat fluxes of 4.7 MW/m², while Europe is providing 215 normal heat flux first wall panels designed for heat fluxes of up to 2 MW/m². For all parties, first wall design, development and qualification has progressed in phases, as teams first manufactured and tested small-scale mockups, then semi-prototypes, and finally full-scale prototypes to prepare for series production. A full-scale prototype of enhanced heat-flux first wall panel with beryllium armour (pictured above)—corresponding to the original design for the first wall—has passed factory acceptance tests (high-heat flux, hydraulic and hot helium leak tests) and demonstrated the necessary technologies (welding, brazing, hot isostatic pressurizing) and production operations. Now that the project is switching from a beryllium first wall to a tungsten first wall, a qualification program has restarted this year at the Efremov. The team is also assessing boron carbide (B4C) as first wall coating to mitigate the tungsten contamination risk during plasma discharge. A large 20-tonne frame has left its manufacturing facility in Bryansk, Russia, for shipment to ITER. The metal structure will be integrated as part of the first test stand that will test vacuum vessel port plugs before their installation on the ITER machine. Finally, Project Center ITER (Rosatom) just shipped a large 20-tonne frame to ITER (grey, in the pink frame above). The metal structure will evenly distribute the weight load of the first port plug test stand as it is used to carry out vacuum, strength, thermal and functional tests on some of the 30 port plugs that will seal off each tokamak port opening and carry diagnostics and heating system elements that are critical to efficient operation. Three stands will be installed on site at ITER (in the former poloidal field coil test facility) to validate the port plugs after they are delivered and before installation on the machine. Each stand, organized within a series of open frames, is a complete system containing heating, vacuum, handling and control capacities that create conditions that are as close as possible to the actual operating conditions of the ITER machine.

Manufactured by Hyundai Heavy Industries, the fourth and last vacuum vessel sector procured by Korea took to the sea on 24 August. The massive 440-tonne component will travel for approximately one month before reaching the Mediterranean. Due to the situation in the Horn of Africa waters, the ship will take the long way home, rounding the Cape of Good Hope at the southern tip of the African continent and sailing all the way north to the Strait of Gibraltar to enter the Mediterranean.

Pre-registration ends on 10 September 2024 for the 13th ITER International School, which will be held from 9 to 13 December 2024 in Nagoya hosted by National Institute for Fusion Science (NIFS), Japan. The theme of the 13th School is "Magnetic Fusion Diagnostics and Data Science." Diagnostics are key to the achievement of ITER fusion power demonstration goals and they require the application of a wide range of techniques. But diagnostics are not enough to ensure ITER's success; only through advanced analysis of the data they provide will it be possible to guide the experiments towards their fusion power goals. It is timely to address these multidisciplinary areas in the ITER school. To register, and for all information, open this link.

Fred Mills of The B1M construction channel on YouTube returned to the ITER site this summer to report on ITER after a first video produced in 2022 amassed 4 million views. In a sleekly produced 30-minute feature he reminds his audience of the potential of nuclear fusion ... and the many challenges. He recounts how the international collaboration got its start in the 1980s, how facility construction began in 2010, and how today, in the context of challenges in assembling the one-million-component machine, the teams are collaborating to solve engineering challenges and deliver solutions. He calls ITER "the planet's most monumental build." The scale of the ambition, the extent of the engineering, the attention to detail is honestly mind-blowing," he says. "It’s hard to think that the place where I’m standing could one become the birthplace of a new form of energy. This spot could literally see the start of something that could change the world."  Views have already topped 450,000. See the video on YouTube here.