There is a new arrival in the tokamak pit—one that upends the perception of space and volume that regular observers had become accustomed to. With the successful insertion of sector module #6 on 18 June, there are now two vacuum vessel sector modules positioned side by side. From every vantage point, it is a spectacular sight.  Two sector modules in two months! Following the insertion of the first of nine vacuum vessel sector modules in April, the assembly teams successfully transferred a second on 17-18 June.The complete lift operation unfolded over three 12-hour shifts—beginning early on Tuesday with a trial lift and ending late the next day with a final in-pit metrology survey. In a departure from the April insertion, the most spectacular part of the operation happened during the 6:00 p.m. to 6:00 a.m. shift, with the ITER Organization construction team, CNPE assembly contractor team, crane operators, metrologists, health and safety officers and observers working throughout the night. Descending slowly: the new sector module had to be lowered especially slowly to avoid the pendulum effect. The two sectors are only 15 cm apart. “We integrated many lessons learned from the first sector module in our planning, and made some changes to the overall organization,” says mechanical engineer Mathieu Demeyere, who supervised the operation for the Assembly & Commissioning Support Division. “One of the things we did differently was to proceed directly to the lift and transfer operation after the positive results were in from the pre-trial test. Last time we had waited until morning, and the load had remained suspended under the cranes without movement all night.”  Most other aspects of the operation were identical. Sector modules #7 and #6 are so similar that the small differences between them (slightly more piping welded on one than the other) did not affect the rigging. The latest sector module followed the same trajectory as the first—vertical extraction from sub-assembly tooling, pivot, transfer across the Assembly Hall and over the tokamak pit wall, pivot and lowering to landing position. Special care was required during the lowering, however, due to the fact that a sector is already installed in the pit. “We proceeded especially slowly during module descent in order to control the ‘swing’ created by the inevitable pendulum effect,” says Demeyere. “And we paused the operation as soon as our instruments detected that movement was increasing.” Burning the midnight oil: the assembly team meets at the beginning of a 12-hour night shift. Earlier, the 1,380-tonne load had been raised 50 cm and the pins attaching it to the assembly tool were released. All is go for its transfer to the pit. Sector module #6 now rests on temporary supports in the tokamak pit and the crane has been disconnected. The two modules in the pit are close to one another but they do not touch—there is approximately 15 cm of space between them. Back in the Assembly Hall, vacuum vessel sector #8 will soon take the place of sector #6 in sub-sector tooling and the process of creating a sector module will begin again. With each complete operation, and there have been three (the first sector module #6 that had to be removed for repair, sector module #7, and sector module #6 again), lessons have been learned and activities optimized resulting in time saved against the calendar: three weeks for sector module #7 and six weeks for sector module #6. A view we hadn’t seen before: two vacuum vessel sector modules side by side in the tokamak pit. “This latest milestone achieved ahead of schedule is the result of hard work performed over the last few years by the repair and sector module assembly teams. All of this would not have been possible without the collaboration and commitment of our industrial partners. We will continue this impressive team effort for the next sectors in line.”See the gallery below for more images of the operation.

As delegates from three continents convened on ITER Headquarters for the 36th Meeting of the ITER Council, construction teams were exiting the tokamak assembly theatre after a long night of work. The insertion—six weeks in advance—of vacuum vessel module #6 in the tokamak pit was a welcome milestone and testimony of continued strong project execution against Baseline 2024. Just two months ago, in April, the first of nine vacuum vessel sectors had been lowered into the tokamak assembly pit. A second was inserted this week in a nighttime operation that ended just as the 36th ITER Council was getting started. Delegates were transported on site to witness the accomplishment first hand and to photograph a striking visual—two vacuum vessel sectors supported side by side in the cylindrical space that suddenly feels quite crowded. ITER Council representatives join ITER officials next to the tokamak pit, where they reviewed the installation of the second sector module on Day One of the meeting. During the presentation of ITER progress by Director-General Pietro Barabaschi, members of the ITER Council heard of other notable achievements since they last met in November: the completion of manufacturing and testing of the sixth module of the central solenoid by the United States, the delivery of the final Korean vacuum vessel sector and the second European vacuum vessel sector, steady progress on component repairs, continued positive interaction with the French nuclear safety regulator, and successful execution of strategies to increase the pace of tokamak assembly. Sector module #6 slowly descends to take its place next to sector module #7 in the pit. Members welcomed these positive developments and spoke collectively to re-emphasize the strong value of the ITER mission. The Council also welcomed the continuing expansion of engagement if the ITER project with private sector fusion initiatives. A second private/public fusion sector workshop was held in April 2025, the first private sector company is participating in the ITPA (International Tokamak Physics Activity), and the sharing of information on the global fusion supply chain is underway. The Council recognizes the value of this private-public collaboration for all Members.Read the IC-36 press release in English or French. ITER Council representatives stand at the top of the tokamak pit, looking down on TWO sector modules in the pit.

Two community events were organized in the past week at ITER. An early start to the day for hundreds of participants to the International Yoga Day event on the ITER site. Hosted by the newly established Consulate of India in Marseille, in cooperation with the ITER Organization, the event was organized before the start of the workday on Monday 23 June.

The power supply system is a vital part of electron cyclotron heating and current drive—the system at ITER designed for plasma initiation, heating, and control. Tests are underway now to prepare the power supply system for integration with the gyrotron microwave generators and comprehensive commissioning.   The power supply system delivers high-voltage, precisely controlled electrical power to gyrotrons—specialized high-frequency microwave generators operating at 170 GHz. These gyrotrons convert electrical energy into electromagnetic waves, which are transmitted into the tokamak via a complex system of waveguides and launchers. When injected into the plasma, the electron cyclotron waves resonate with a cyclotron motion (also known as gyromotion), efficiently heating the plasma and driving localized current. The main high voltage power supply (MHVPS) delivers DC voltage up to -55kV DC to the gyrotron cathode, to enable the emission of electrons that are then accelerated and manipulated to produce high-power microwaves. Prior to the first energization of the MHVPS with the ITER pulsed power electrical network’s 22kV distribution grid, a series of verification and validation tests were conducted to ensure safe operation. Following this initial energization, various functional tests will be carried out to confirm that the power supply's performance and protection functions meet the technical specifications. These tests are essential before integrating the MHVPS with the gyrotrons for comprehensive commissioning.

The cryostat is not yet in place, but operators have practiced the sequence of operations that will be needed to deliver a toroidal field coil to the new magnet cold test facility at ITER. A cold test facility for ITER magnets is being set up in the former Poloidal Field Coils Winding Facility, where the gantry crane that transported late-stage poloidal field coil assemblies can be repurposed to transport toroidal field coils into the test bench cold chamber ("cryostat").In the photo above, a toroidal field coil has been lifted and transported to the exact position of the future cryostat as part of a test operation; it hovers just 30 cm above what will be the height of the future equipment.The yellow attachment under the red beams of the gantry crane is a bespoke lifting adapter that corresponds to the D-shape of the toroidal field coils (the poloidal field coils are ring shaped, so the original adapter could not be used). In addition, a transverse positioning system has been procured and attached to the gantry crane to allow fine positioning in the direction perpendicular to the gantry axis. This is needed for the operation ahead, as the gantry crane can only move in a single direction.The first-of-a-kind testing concluded successfully. The objective—which was to confirm the ability of the equipment to position a toroidal field coil within an accuracy of +/-1mm inside of the test facility's cryostat—was attained, and the team benefitted from a hands-on training opportunity. The first "real" lift operation is expected in December.

Vacuum vessel sector #4 has been rotated to its other side in a gold medal outdoor performance. In an unprecedented operation that saved assembly time and eased congestion in the Assembly Hall and tokamak pit, vacuum vessel sector #4 has been successfully rotated by a huge gantry crane outdoors so repairs could be made to its inaccessible side.With onlookers gathering throughout the 11-hour operation, the 378-tonne sector (nominal delivery weight) was raised into the air on a giant gantry on Tuesday 17 June, where it then performed a slow but spectacular gymnastics-like manoeuvre. “It was exceptional to watch,” says Donato Lioce, ITER’s deputy Tokamak Program manager who oversaw the rotation. “We moved from a concept on a PowerPoint to a first-of-its-kind operation in just two months and it’s thanks to the whole team that this was a success.”Over the past year, there have been ongoing repairs to the vacuum vessel sectors to even out faulty sections of interface surfaces (bevels) where they will be welded together. For the vacuum vessel sectors being repaired in a horizontal orientation, once one side is repaired the sectors need to be flipped so the work can be done on the other side. For vacuum vessel sector #8, this flipping was executed using the upending tool and a roundtrip voyage into the tokamak pit.  It took 11 hours to raise, rotate and set back down vacuum vessel sector #4. By devising an outdoor solution, time was saved and extra congestion in the indoor assembly spaces was avoided. However, because of the limited space in the tokamak pit and the high demand for time on the upending tool, an audacious plan was devised in April 2025 to rotate vacuum vessel sector #4 outdoors. This promised to save about three weeks on the baseline schedule by bypassing the wait for the upending tool while also eliminating a bottleneck in the assembly arena and giving ITER valuable experience with an alternative method for rotating vacuum vessel sectors.In close collaboration with Mammoet, the company that provided the massive gantry and logistics support, the vacuum vessel team engineered the rotation over the past two months to ensure it could be performed without risk to the component while meeting the most stringent safety conditions. With technicians from the European consortium that had manufactured the sector, six temporary lifting lugs were welded onto the sector so it could be attached to the gantry while two lifting beams were manufactured to serve as braces during the most taxing parts of the procedure.The outdoor rotation plan was developed by ITER engineer Alex Martin and as he did the modelling, he noticed that the planned movements resembled what he had seen during an Olympic gymnastics competition. Sure enough, vacuum vessel sector #4 would be performing an Amanar vault on the gantry, one of the most challenging moves in women’s gymnastics. And, just like with Olympic gymnastics, the landing was essential as the vacuum vessel sector had to come gently down on supporting blocks with a margin of only a few millimeters for error. Work on the outdoor rotation plan only began in April 2025. Two months later, the operation was a success. “The entire routine went smoothly and we hit our landing,” says Alex Martin. “We can proudly say we performed like Olympic champs.”Vacuum vessel sector #4 has now been moved back into the former Cryostat Workshop, where the temporary lifting lugs will be removed and repairs on the bevels will be finished. With the first operation a success, the team is now scheduled to rotate vacuum vessel section #1 outdoors at the end of June 2025.