With a final dollop of vibrant Smurf blue goo, another penetration benchmark was reached in December—the infilling of 15 busbar openings on the L3 and L4 levels of the Tokamak Building. For this project, the infilling team spent months qualifying a bright blue elastomer produced by the Norwegian company Elkem to ensure it met the required fire segregation, radiation shielding, leak-tightness confinement function and other standards. Among other assessments, the fire qualification tests included heating the elastomer to 1100 °C in a specialized furnace and ensuring it did not permit a heat transfer in excess of 120 °C on the other side of the opening. By undertaking this qualification process, which was done in partnership with the Efectis laboratory in France, the teams ensured that future fusion construction projects can use this elastomer product from day one if they have matching safety requirements. The elastomer is readied by mixing two different liquids and then pressurising it to remove the gas bubbles. Here, Arturo Pascual Rubio of GDES checks the mixture. “This was the first time this type of infilling had been done at ITER, so we had a very complex problem and, together, we found a simple solution,” says Jose Manuel Sanchez Cuevas, the mechanical and piping supervisor who was the contract responsible officer for the busbar infillings.There are thousands of small penetrations (openings) in the Tokamak Complex to allow pipes, cables and components to pass through walls and slabs. These penetrations need to be infilled using different solutions that meet the same safety and nuclear safety standards as the surrounding wall material. Any elastomer splatters need to be carefully cleaned off the busbars after the pouring is completed. As further infilling gets designed, ITER will spend many more months qualifying dozens of formulas to ensure they meet the safety requirements. At the end of these qualification efforts, a catalogue of products and solutions will be available for future fusion construction projects.The infilling of the busbar penetrations with bright blue elastomer is part of a broader contract being fulfilled by the Spanish company GDES. The team is now turning its attention to a new set of 150 penetrations. The team behind the busbar infilling project: Bottom row from left to right: Saulo Torres Da Silva, Samuel Pérez Grimaldi, Gabriel Argilés Monteagudo, and Pablo Calderón Escudero. Top row, from left to right: Jose Manuel Sanchez Cuevas, Arturo Pascual Rubio, Mathew Jacob Nobi, Manoj Panchal, and Cristina Serrano Gil.

For the past two years, ITER has opened its doors to private sector fusion companies for joint workshops on areas of mutual interest and mechanisms for positive engagement. This year’s workshop will take place on 28 and 29 April (Tuesday and Wednesday), with Monday 27 April and Thursday 30 April set aside for consultations with ITER experts, tailored tours of the ITER worksite, and interactions among participants. This year’s theme—“Fusion: a Joint Quest”—reflects the reality that progress toward fusion energy is neither linear nor uniform, but pursued through multiple technical approaches, institutional models, and timelines. Across public and private efforts alike, divergent visions coexist with genuinely complementary strengths—in science, engineering, manufacturing, and systems integration.At ITER, where large-scale construction and operation depend on sustained cooperation across sectors and geopolitical boundaries, engagement is not a matter of persuasion or consensus, but of disciplined, practical collaboration: the exchange of data, designs, expertise, and hard-won experience. This workshop embraces healthy disagreement as an ongoing feature of the fusion landscape and treats engagement itself as an asset—one that, when pursued seriously and respectfully, yields tangible value for all participants. The aim is not to resolve differences prematurely, but to ensure that they sharpen, rather than fragment, the collective effort.All those who have participated in the past two workshops, as well as those interested in participating this year, are invited to take the survey below. Elements of the proposed agenda are covered in the survey, and this is your opportunity to further shape the agenda to match your needs and interests. Click to participate in the survey for the 3rd ITER Public-Private Fusion Workshop.Learn more about the 2024 and 2025 workshops.

In December, the International Tokamak Physics Activity (ITPA) became the International Tokamak Physics and Engineering Activity (ITPEA). The International Tokamak Physics Activity (ITPA) was established in 2001 under the auspices of the International Atomic Energy Agency and, since 2008, has operated under the ITER Organization. To date, the ITPA has coordinated research among the ITER Members to develop the physics and operational basis of burning tokamak plasmas for ITER, as well as for other fusion programs and for progress toward fusion energy in general. It has worked to achieve the broad physics basis behind ITER's design and is working on the optimization of its scientific exploitation (ITER Research Plan) through R&D carried out by seven ITPA Topical Groups.Now, as ITER moves closer to integrated commissioning and research operation, international collaboration is evolving to ensure that not only the physics behind ITER but also the engineering knowledge is effectively shared to support successful operation. In 2025, the Coordinating Committee (CC) of the ITPA therefore decided to expand the Activity’s scope to formally include engineering activities. This process culminated at the ITPA CC meeting held at ITER Headquarters from 3 to 5 December 2025. As a result, from 2026 forward, the ITPA has a new name—the International Tokamak Physics and Engineering Activity (ITPEA)—and a new Charter. This new scope means that engineering and operational aspects of tokamak systems will now be part of the ITPEA activities. Two new Topical Groups have been created to coordinate activities in the areas of magnets, cryogenics and power supplies and in tokamak operations. The Magnets, Cryogenics and Power Supplies Group focuses on issues related to the design and operation of systems required for superconducting magnet operations in fusion devices, including their commissioning. The Tokamak Operations Group covers all practical aspects of operating tokamak components and systems like integrated commissioning and fuel cycle (including the tritium plant and interfaces with the tokamak). The engineering of other ITER components and systems will be addressed within the existing groups that are already carrying out associated research (e.g., aspects of the disruption mitigation system will be addressed in the MHD, Disruptions and Control Group, while heating and current drive will be addressed in the Integrated Operations Scenarios Topical Group).The ITPEA, with its renewed scope, will effectively support preparations for tokamak operation with burning plasmas in ITER as well as, more generally, in the ITER Members.

As the project advances toward the construction and operational objectives defined in Baseline 2024, integrated commissioning has become increasingly central to ensuring ITER’s success. Instead of progressing as originally planned toward a modest first-plasma demonstration at low current, ITER is now preparing for a more robust start to scientific exploitation, with hydrogen and deuterium plasmas and pulses up to 15 MA during the first research phase. â€œWe are going to do many more things than we had originally planned,” says Isabel Nunes, Commissioning & Operations Responsible Officer. “Before, we were just demonstrating breakdown. Now we are actually performing the first objectives of our Research Plan.”ITER’s Start of Research Operation (SRO) phase will require all of the essential systems needed for sustained pulses—a blanket, inertially cooled first-wall panels, the divertor, and magnets performing at full magnetic energy. â€œStarting with normal plasma operation, and not just a limited demonstration, means that our work has expanded dramatically,” says Nunes.What has not changed is the definition of integrated commissioning, which is the systematic process of testing, verification, and fine-tuning of interconnected plant systems to ensure they are ready for operation.The first round: for Start of Research OperationThe objectives for ITER’s first integrated commissioning phase include demonstrating that ITER can achieve the vacuum conditions required for plasma operation, cooling and energizing the superconducting magnets to full performance, and integrating the control, safety, fuelling, and heating systems required for the first campaigns.The work begins with pump-down and leak testing of the vacuum vessel and cryostat, followed by a carefully controlled cooldown of the superconducting magnets to 4.5 K—a slow, cautious process. â€œThis will be the first time* we cool down the superconducting coils, so we have to go slowly,” Nunes explains. â€œAs we energize the coils, the forces can be huge—they can damage a coil if we’re not careful.”From there, teams take on many of the tasks that were once distributed across several later phases. Wall conditioning is one of the largest. â€œWe expect to spend two months preparing the inner wall of the vacuum vessel for operation,” says Nunes. â€œYou have to remove water, oxygen, hydrogen, hydrocarbons—everything that would cool the plasma and prevent breakdown.”Diagnostics and magnetic systems add another layer of complexity, requiring parallel activity during magnet energization. â€œWhen you energize the coils, you are also calibrating the magnetic diagnostics, and at the same time checking the cooling because the temperature rises,” Nunes explains. â€œEverything must be coordinated.”Under the new plan, all of these tasks must be performed in approximately 18 months—a much more ambitious set of activities for first-phase commissioning (IC-I) than in the previous baseline. The path from construction to integrated commissioning—a question of planning and coordination. The second round: for the first deuterium-tritium phaseAfter the Start of Research Operation phase, expected to last 27 months, major new hardware will be installed—and that means another round of commissioning.ITER’s permanent first wall, and the installation of neutral beam injectors, additional heating and four test blanket modules (TBMs) will require system-level testing first, followed by full integration into the rest of the plant. The objectives of second-phase integrated commissioning (IC-II) are to integrate the tritium fuel cycle, commission the test blanket modules and their lithium-lead and helium-cooled loops, condition the neutral beam injectors up to 870 kV with hydrogen, and complete the safety and interlock systems required for burning-plasma operation.IC-II also includes recommissioning all the systems validated in the first integrated commissioning and operation phase. Diagnostics must be re-aligned and recalibrated, additional heating gyrotrons and beamlines must be integrated, and shielding performance must be assessed using radioactive sources to benchmark radiation transport models for the next operational phase, DT-1 (Deuterium-Tritium 1). The license to introduce tritium depends on these activities being completed successfully.Every time the vacuum vessel is vented, we need a restart phase, says Nunes. â€œYou have to cool down again, energize the coils, bake the vessel, condition the walls, and remove impurities.” The same logic applies to software and control systems: â€œEvery time we restart, we recommission if a system has changed or been upgraded but also if no changes were made, because we must demonstrate that the software and hardware still work as expected.”This disciplined cycle—commission, operate, vent, recommission—ensures that system functionality remains predictable and safe as ITER moves towards full fusion performance.The philosophy behind ITER’s commissioning strategy is to build capability step by step. â€œThe goal is to arrive at the end with a tokamak and a plant that are ready for plasma operation,” says Nunes. â€œEverything must already work the moment we start plasma commissioning.”*Several of ITER’s toroidal field magnets and one poloidal field magnet will be cooled down and tested in the on-site magnet cold test facility. The central solenoid magnets were also cold tested at their operating temperature of 4 K.

Recruitment opens today for eight Postdoctoral Fellowships at the ITER Organization. The ITER Organization invites applications to the ITER Postdoctoral Program, which aims to attract outstanding PhD graduates in science, technology, and engineering whose expertise aligns with the needs of the ITER project. Selected candidates will be appointed to two-year postdoctoral positions, working closely with ITER specialists and contributing to the project through original research.For the 2026 campaign, the ITER Organization seeks to recruit eight Postdoctoral Fellows across seventeen defined research topics (see detailed topic descriptions here). Applications are open exclusively to postdoctoral researchers with demonstrated experience in one or more of the proposed research areas.The eight Postdoctoral Fellowships are proposed through two different funding schemes: Monaco/ITER Postdoctoral Fellowships (5 positions)The Principality of Monaco is providing the financing for five Postdoctoral Fellowships through a Partnership Arrangement signed with the ITER Organization in 2008 and renewed in 2018. You can apply to a Monaco/ITER Postdoctoral Fellowship if: 1) you are a national of China, the European Union plus Switzerland, India, Japan, Korea, Russia, the United States, or the Principality of Monaco; and 2) your PhD was awarded after 1 January 2023 (or you will have received your PhD before 31 December 2026).Korea-ITER Postdoctoral Research Fellowships (3 positions)Through an agreement signed between the ITER Organization and the Korean Domestic Agency, ITER Korea directly funds scientific or technical fellowships in fields of mutual interest and with a view to contributing to training the talent that will be needed for the fusion industry of the future. To apply for a Korea-ITER Postdoctoral Research Fellowship you must be a Korean postdoctoral researcher.The application process for both Fellowship categories is the same: after verifying that you have relevant experience in one or more of the 2026 research topics, apply by 1 March 2026 through the ITER Jobs portal.KEY DATES FOR THE 2026 ITER POSTDOCTORAL PROGRAM12 January 2026: External launch of competition1 March 2026: Deadline for applications7, 8 & 9 April 2026: Candidate interviews1 September 2026: Fellows normally on site31 December 2026: Latest date for Fellows to take up award on siteSee this ITER webpage for more information. If you would like to advertise these opportunities in your research institute or university, download the poster for the 2026 ITER Postdoctoral Program here.

The 360° virtual tour of the ITER construction site has been updated with a new set of photos—drone footage from December 2025 that shows three vacuum vessel sector modules in the tokamak pit. Click on and rotate the new photos in the Tokamak Pit gallery to see one-third of the ITER plasma chamber from every angle.Accessible from the NEWS & MEDIA pages of the ITER website or by clicking on the link below, the 2D tour requires no special equipment to enjoy. If you do have 3D glasses, click on the yellow goggle symbol at the top of any screen.Click here to see the latest 360° ITER virtual tour.