At a recent five-day workshop at ITER, researchers traded best practices in simulating the plasma periphery—the critical buffer region between the hot core and the solid wall elements of a tokamak. A powerful tool in their arsenal is the SOLPS-ITER code, introduced 10 years ago by the ITER Organization for tokamak edge simulations. On the road to making fusion power production a reality, one of the main issues to solve is the interaction between the plasma edge and the plasma-facing armour protecting the confinement vessel. Beyond the last closed magnetic surface defining the boundary of the core plasma a narrow region is formed, called the scrape-off layer, in which the plasma flows to special divertor targets located away from the main plasma. In addition, turbulent transport carries some of the plasma particles and energy radially outward to the main wall surrounding the core. Because plasma contact with the walls can lead to erosion, damage, material migration, and fuel retention, it is important to fully understand all the processes and their impact on plasma behaviour and device operation through careful modelling of the physics involved.At the ITER Organization, the Science Division is actively involved in developing and maintaining software tools to enhance our capacity to predict the edge plasma behaviour—an activity carried out in collaboration with experts from across the ITER Member States and beyond. One of the main tools is the SOLPS-ITER code. Launched 10 years ago by the ITER Organization, it is now the most advanced version of the long series of SOLPS code releases which have been the main workhorse for ITER divertor design.Edge modelling took on a renewed importance at ITER during the re-baselining activities of 2023 and 2024, as the change in wall material from beryllium to tungsten brought increased focus on plasma-wall interactions. In particular, detailed calculations of the plasma heat loads and particle fluxes onto plasma-facing components are essential to inform the design of the first wall armour—both the inertially cooled design which will be installed for the Start of Operation Phase, and the actively cooled final variant to be used throughout deuterium-tritium operation. The recent update of SOLPS-ITER to “wide grids,” meaning with a computational domain extending all the way to the plasma-facing surface contour, is particularly well-suited to this purpose and has provided a new tool for the community to look at these issues. SOLPS-ITER Code Camp participants, dressed for a visit to the construction site. It is in this context that during the week of 29 September to 3 October, the ITER Organization hosted an edge modelling Code Camp, focused on use of the SOLPS-ITER code. About 40 researchers from all over the world attended in person, including registered participants from all seven Members States and some private fusion ventures, plus many others connecting remotely to listen to presentations and join in the lively discussions. This Code Camp, the twelfth since the SOLPS-ITER launch and the first to be hosted by the ITER Organization, continues a long list of such events. Previous Camps took place in Yokohama, Japan, in 2015 and 2023; San Diego (California), United States, and Garching, Germany, in 2016; Daejeon, Korea, in 2017; Hefei, China, in 2018; Oak Ridge (Tennessee), United States, in 2019; Leuven, Belgium, in 2022; Knoxville (Tennessee), United States, in 2023; Dalian, China, and Prague, Czech Republic, in 2024.This time, the topics covered included the latest results from ITER simulations using the wide grid code version on tungsten walls, various numerical recipes to improve code convergence and run stability, new data visualization options based on the ITER Integrated Modelling Analysis Suite (IMAS) framework, ways to set up more accurate time-dependent simulations, and much more. Participants were also able to see for themselves the progress made on the ITER machine assembly, giving a concrete purpose to their work. As in previous Code Camps, the gathering of experts for a full week led to many fruitful discussions, ideas for further collaborations, users helping each other with problematic cases, suggestions (and implementation!) of code improvements, and a sustained sense of community. And all are looking forward to the next opportunity to meet. 

See the latest image of work underway in the ITER machine assembly pit. With the interfaces for the tokamak cooling water system now in place (see the “pipes within pipes” visible at the top of this image), the upper levels of the tokamak assembly pit recently received a new coat of white paint. Gone are the large handwritten numbers which, for years, puzzled visitors—a decisively low-tech information system for the most technically complex machine ever designed. (The numbers identified the 18 penetrations for the cooling water pipes).The white paint, the white wrapping of the gravity supports for the toroidal field coils, the fire-like lights in the very centre of the pit under the correction coils (wrapped in pink), the dull shine of the steel cryostat, and the massive and soaring central column all contribute to the atmosphere of this “Image of the Week”—the beauty and mystery of an environment without equivalent on this planet.

On Tuesday 7 October, dignitaries and guests celebrated the many vital contributions India is making to the project. The overall message: “India is committed to the success of ITER at the highest national level.” It was only eight months ago that Prime Minister Narendra Modi was able to take stock of ITER progress in person, as he toured the machine assembly areas of the worksite in the company of French President Emmanuel Macron.This time the delegation from India was led by Vijay Kumar Saraswat, a distinguished scientist and former Head of India’s Defence Research and Development Organization who is currently a member of the top public policy think tank, NITI Aayog. The Project Director of ITER India, the Consul General of India in Marseille, and representatives from the Indian Embassy in Paris and from Indian industry joined him for a full day of events that got off to a start in the ITER amphitheatre with representatives of the ITER management team and Indian staff members and ITER Project Associates. Vijay Kumar Saraswat, a member of India’s public policy think tank NITI Aayog, tours the ITER cryoplant. He had detailed questions for the ITER team, including David Grillot, who heads the Controls & Integrated Commissioning Program (seen speaking) and Construction Project head Sergio Orlandi (background, blue hat). V.K. Saraswat spoke at length to those who were assembled, describing how he sees the role of nuclear energy—including fusion—in the future energy mix and in the decarbonization efforts of his nation.He estimates that the demand for energy in India will double by 2047. The country has an ambitious nuclear energy roadmap that aims to reach 100 GW of capacity by that date, up from approximately 9 GW of installed capacity currently. This goal is largely based on fission reactors, but in his opinion, India must develop its fusion technology if it wants to achieve its goal. V.K. Saraswat told the assembly that “the perceived potential of fusion is recognized in long-term energy security policy in India.” The ITER management team welcomes the Indian delegation. From left to right (front row): head of the ITER Construction Project S. Orlandi; B. Sarkar, Senior Expert at ITER; U.K. Baruah, head of ITER India; P. Kulkarni, Executive Director of INOXCVA; ITER Director-General P. Barabaschi; V.K. Saraswat, NITI Aayog; Vice President Larsen & Toubro Heavy Engineering, P. Bhatt; Tata Consulting Engineers, Vice President & Business Head R. Raghavan. From left to right (back row): Assistant General Manager INOXCVA V. Gehani; Head of the Office of the Director-General K.R. Sriram; Head of the ITER Engineering Services Department D. Lockridge; Dr T. Raja, Principal Chief Scientist, CSIR-National Chemical Laboratory, India; and Head of the ITER Science & Integration Department A. Bécoulet. As is the case for other Members, he said, ITER remains a “key element” in India’s fusion research plans. “India’s participation in ITER has directly accelerated our domestic fusion capabilities, both technologically and institutionally.” He cited the training of staff, the creation of a domestic supply chain and world-class test facilities (see here and here), and the development of advanced technologies to ITER specifications as examples. “India is committed to the success of ITER at the highest national level.”Representatives of Larsen & Toubro, INOXCVA and Tata Consulting Engineers (TCE) shared the ways in which participating in the ITER program has improved their competitiveness and not only in the domain of fusion.  The ITER Director-General presents V.K. Saraswat with a small piece of ITER superconducting cable and thanks him for his encouraging words on India’s commitment to ITER. ITER Director-General Pietro Barabaschi thanked the group for the passion in their commitment to the project and highlighted that—above and beyond India’s formal in-kind contributions to ITER—it has been critical in recuperating some of the delays of the past years by participating in the repair campaign for the thermal shields and “placing us in a very good position for the machine assembly activities ahead.” The ITER Director-General also noted that it has been exactly 20 years since India joined the ITER project. “We are encouraged by your words of support. People from all over the world are contributing their energy to this project, and they are bringing back their experience to their home countries. To succeed internationally in fusion, we will need many national initiatives. ITER serves this purpose—as a 'breeding ground' for competencies that can be fed back to national programs.”See a related report on the ITER India website. Viewing the tokamak pit, where currently two of nine vacuum vessel modules are in place and a third is expected before the end of the year.

Their Imperial Majesties Emperor Naruhito and Empress Masako of Japan wished the ITER team success as they visited the ITER Organization booth at the Osaka World Expo in early October. On Monday, 6 October, Their Imperial Majesties Emperor Naruhito and Empress Masako of Japan graciously visited the ITER exhibition at the 2025 World Expo in Osaka. This marked Their Majesties’ second appearance at the Expo, following their distinguished presence at the opening ceremony held in April.Deputy Director-General Yutaka Kamada and Expo Commissioner General Takayoshi Omae had the honour of presenting the vision and mission of ITER. The presentation encompassed the scientific fundamentals of fusion energy, the framework of international collaboration underpinning the ITER project, and the principle technical features of ITER machine under construction.Their Majesties engaged with sincere interest, posing thoughtful questions regarding the principles of fusion reaction, the global talents contributing to the project, and the defining technical characteristics of the construction process. Her Majesty the Empress concluded the visit with words of encouragement: “Please make it a success.” Photo credit: EXPO 2025 Since the commencement of the Expo, the ITER booth has welcomed over two million visitors, reflecting the public’s profound interest in the future of clean energy.The 2025 World Expo concludes on 13 October, following six months of unprecedented participation and global engagement.

The World Expo in Osaka, Japan, has closed its gates after six months and more than 28 million total visitors, 2 million of whom stopped by the ITER stand. There were a lot of handshakes and some shoulder clapping in the big auditorium where EXPO 2025 staff had assembled for the closing ceremony that marked the last push across the finish line. Relief was in the air but also a sensation of accomplishment and pride. No one had foretold the crowds that appeared at the Expo site every day by the hundreds of thousands, stoically waiting in queues for up to five hours to enter one of the pavilions, including on the hottest or most inclement days. All to experience different cultures, discover diverse national heritages, or learn about new technical developments—sensations that smartphones or social media cannot provide.In an impressive closing ceremony, the baton was passed to Belgrade, Serbia, where the next World Expo will be organized in 2027.Au revoir Osaka!

For two weekends in October, ITER volunteers carted folding tables, fusion demos, virtual reality headsets and giveaway goodies to gymnasiums and cultural centres in the region for the annual "celebration of science" (Fête de la science) in France.  Each day ended with hoarse voices and depleted stocks—every bag of marshmallows empty, every ITER pen distributed, and demo batteries flashing red. Participating in day-long Fête de la science event takes stamina! Families come in waves, with children hoping to participate in every fusion demonstration and queuing to strap on the VR headset that transports them around the gigantic ITER worksite or inside the machine. Over the weekends of 4-5 and 11-12 October, the ITER Organization took part in events in three cities—Villeneuve-Loubet, Manosque and Marseille—managing a total of eight days with 17 hardy volunteers.See some scenes from their interactions with the public below.

According to the IAEA’s Fusion Device Information System (FusDIS), there are almost 150 experimental fusion devices and testing facilities either operating, under construction or in the planned stages, and more than 20 fusion plant designs under development. Recent scientific and technical advances, coupled with a dynamic private sector, and the pressing concerns of climate change and energy security, have shifted the focus toward addressing the remaining challenges. These include demonstrating the technological feasibility of fusion power and ensuring its safety and economic viability as a sustainable energy source.Through its series of Fusion Energy Conferences (FECs), the International Atomic Energy Agency (IAEA) has long fostered the exchange of scientific and technical results in fusion R&D. The 30th edition of the FEC—which formally opens tomorrow in Chengdu, the capital of China's Sichuan province—is intended to reflect the priorities of this new era in fusion energy research, development, demonstration, and preparation to deployment.ITER staff members will be participating in the technical program, leading sessions on ITER technology, science and construction. ITER Director-General Pietro Barabaschi will present the progress of the ITER project and its value for fusion. And, parallel to the conference, the Second Ministerial Meeting of the IAEA World Fusion Energy Group will take place on Tuesday 14 October, one year after its inaugural meeting. Newsline will have a full report next week.Click to see the IAEA FEC 2025 general conference website and the conference program.