After a two-year shutdown for upgrades, the SPIDER testbed at the ITER Neutral Beam Test Facility in Padua, Italy, is preparing for commissioning and operation. SPIDER is a full-size negative ion source that is designed to demonstrate all the critical aspects of the ion sources for ITER's heating and diagnostic neutral beam injectors. Following a comprehensive upgrade, the SPIDER beam source is back within its vacuum vessel, bringing the negative ion source testbed that much closer to commissioning and a new phase of operation. According to NBTF Project Manager Diego Marcuzzi, the shutdown has set the stage for SPIDER to achieve the performance targets required by ITER in terms of ion beam density, and beam uniformity and divergence. © Maria Teresa Orlando The ITER Neutral Beam Test Facility (NBTF) is hosted by the Italian research laboratory Consorzio RFX and funded by the ITER Organization, the European Domestic Agency and the Italian government. The European, Japanese and Indian Domestic Agencies are all contributing with in-kind components and plant systems; the European Consortium for the Development of Fusion Energy (EUROfusion) is also participating under the terms of a Cooperation Agreement signed in 2020. In operation since 2018, SPIDER successfully completed its first campaign in 2021. Based on the results of this campaign, upgrades representing an investment in the range of EUR 1.5M were designed and carried out. "With approximately 60 procurements for new or revised components for beam source enhancement, the shutdown has set the stage for SPIDER to achieve the performance targets required by ITER in terms of ion beam density, and beam uniformity and divergence," says Diego Marcuzzi, NBTF Project Manager. In shaping these advancements, the NBTF team focused on a challenging activity program of design, simulation and modelling for the experiment upgrade, followed by the realization by industry of the modifications, which are intended to fine-tune one of the most critical components of ITER's neutral beam injector system—the beam source. The beam source is lifted for installation. During the shutdown there were approximately 60 procurements for new or revised components for beam source enhancement. © Luca Lotto "Our goals were twofold: to achieve a denser and more uniform plasma within the drivers and the plasma expansion chamber, while simultaneously reducing the cause of electrostatic discharges," explains Mauro Pavei, Responsible Officer for the SPIDER beam source. "The three years of operation on SPIDER had clearly indicated where and how to act. Therefore, the main functional modifications to the drivers began before the shutdown, starting from an intense design activity aimed at optimizing plasma confinement in the drivers and solving the issue of electrostatic discharges through the introduction of new electromagnetic screens and optimization of various details of the electrical circuitry in vacuum. In addition, during the disassembly phase, some phenomena were observed that required engineering improvements, particularly on the molybdenum coating of the plasma-facing components." SPIDER has also been enhanced with new diagnostic systems to measure the uniformity of the plasma and of the beam, both with the introduction of fixed probes at the driver level, in the bias grid, and by electrically isolating individual segments of the extraction grid. "This required a revision of the geometry of some components and the careful installation of additional equipment, without perturbing the voltage-holding capabilities," says Gianluigi Serianni, NBTF Scientific Exploitation Leader. "For instance, one of the largest flanges on the vacuum boundary was modified to allow a significant increase of acquisition capabilities and consequently diagnostic monitoring. Moreover, an important test will be performed on a largely modified plasma generator." Behind the scenes of this hard work, which has required more than two years of teamwork, there is the strength of a joint scientific collaborative effort driving the project forward. A collaboration that has recently seen Indian colleagues from ITER India/Institute for Plasma Research joining the NBTF team in view of the SPIDER enhancements. In the next months, the modifications introduced in SPIDER will be tested. All the attention is now on the next operational campaigns, which will hopefully provide a further increased momentum in advancing development to provide ITER with reliable, high-performance neutral beam injectors.

New results published in Physical Review Letters suggest that instabilities driven by energetic particles can have a positive impact on fusion performance. Figure 2: Perturbed fraction of the energetic particle distribution in phase space without (left) and with (right) the inclusion of fishbone-generated plasma flows. In the 150-million-degree burning plasma of the ITER Tokamak, a fraction of the particles will be even hotter—with temperatures on the order of 15 billion °C. These energetic particles, born from fusion reactions or the auxiliary heating systems, are essential to maintaining the self-heating of the plasma, key to achieving high performance in future fusion reactors. However, the presence of energetic particles can drive instabilities in the plasma core, such as the so-called "fishbone" instability that is named for the way it appears on the magnetic measurements (see Fig.1). If the amplitude of this instability is large enough, it can lead to a redistribution of energetic particles out of the plasma core, deteriorating the plasma's self-heating process. Through an international collaboration involving researchers from the ITER Organization, the United States, France and China, scientists have shown for the first time that the amplitude of the fishbone instability can be significantly reduced by the self-generation of strong flows within the plasma (see Fig. 2). This research was carried out using state-of-the-art plasma simulation software developed at the University of California Irvine, the Princeton Plasma Physics Laboratory and the École Polytechnique in Paris. The simulations described an experimental plasma discharge from the DIII-D tokamak at General Atomics (San Diego, USA) that was chosen to capture the dynamics of energetic particles in ITER. This experiment featured a sharp increase of plasma performance during the excitation of fishbone instabilities.

As part of work underway to update the ITER Project Baseline, a group of experts nominated by the Members met in February to evaluate the new blueprint for achieving ITER's research goals. The ITER Organization will submit a new project baseline to the ITER Council for consideration in June 2024. Taking into consideration past delays incurred due to the Covid-19 pandemic, repairs to key components and other technical challenges with first-of-a-kind components, and a revised path to nuclear licensing, the new baseline proposes an optimized path to achieving the project's goals. The new baseline includes modifications to the configuration of the ITER device and its ancillaries (e.g., a change from beryllium to tungsten as first wall material, modifications to the heating and current drive mix, etc.) as well as additional testing of components (e.g., toroidal field coils) and phased installation (starting with an inertially cooled first wall and installing the final actively water-cooled components later) to minimize operational risks. In this new approach, scientific exploitation is divided into three main phases: Augmented First Plasma, DT-1 and DT-2 plus the associated integrated commissioning phases. In its September 2023 meeting, the ITER Council Science and Technology Advisory Committee (STAC) found the plan compelling and recommended that this outline be adopted for the further articulation of the new ITER Research Plan to be elaborated by the ITER Organization and Member experts. Participants to the ITER Research Plan development workshop during a visit to the ITER Assembly Hall. To this end, in late 2023, each ITER Member nominated five experts, with a preference for younger contributors who will have a greater opportunity to be involved in ITER's scientific exploitation. Following some preparatory teleconference meetings in 2023 and early 2024, the first new ITER Research Plan development workshop took place at ITER headquarters from 13 to 15 February. The meeting began with presentations by ITER staff describing the details of the new ITER Baseline and ITER Research Plan, followed by joint analysis of the main objectives of the various Research Plan phases, the suitability of the configuration of the ITER device and its ancillaries to achieve these objectives, and the expected operational time for each phase. Detailed evaluations were carried out by five working groups jointly led by staff from ITER and Member experts over three intense days, concluding with a final session during which all the groups reported their findings. Overall, the analyses of the working groups found that the main elements of the outline Research Plan submitted for review to STAC in September 2023 were appropriate. However, the groups identified specific aspects of the outline plan which require further review and optimization. As an example, it was concluded that the demonstration of Q=10 operation in short burn (~ 50 s) could already be achieved in the third of up to five planned campaigns in the DT-1 phase, even if the final goal of Q=10 for 300-500 s may have to wait until later in DT-1.   This new ITER Research Plan development workshop will be followed by further analysis of the issues and optimization possibilities identified during what was an extremely beneficial gathering of experts. This work will be performed via email and videoconference by the same groups in the next weeks in preparation of a second, probably virtual, workshop to be held in late March. This will allow the details of the new ITER Research Plan to be finalized in time for submission for endorsement to the STAC in May.

On Friday 16 February, a toroidal field coil was moved from the Assembly Hall to a storage place a few hundred metres away. Quite a routine operation at ITER, and yet this transfer was a world premiere. The trailer that transported the 350-tonne component was powered by a first-of-a-kind electrical unit specially developed by Dutch specialist Mammoet for ITER and global logistics provider DAHER. For years, since ITER began handling massive components on site, transfer operations have depended on self-propelled modular trailers (SPMT) equipped with conventional diesel power pack units (PPU) pumping high-pressure oil into the trailer's hydraulic motors. Diesel motors are powerful and dependable but also noisy, and their exhaust—although filtered and evacuated when the SPMT is operating inside a building—is heavy with fumes and fine particles. One of the main challenges for Mammoet in developing an all-electric version was to fit a powerful electrical motor and 1.5 tonnes of batteries into the existing power pack frame, so that no specific adaptation would be needed to connect it to the SPMT. "The e.PPU, as we call it, develops an equivalent power and much bigger torque than its diesel equivalent," explains Michel Bos, who oversaw the development of the system at Mammoet. The power pack's batteries deliver 320 kW of power, equivalent to 460 hp, and can handle two days of standard operation on site before requiring a charge. A five and a half hour connection to a 63A electrical outlet is sufficient to bring the batteries back to full capacity. The batteries of the electric power pack (on the left) deliver 320 kW of power, equivalent to 460 hp, and can handle two days of standard operation on site before requiring a charge. (In order to avoid a complex reconfiguration, and also to have a backup, the diesel power pack unit on the right was kept attached to the trailer.) Another advantage of the electric motor is silence. At 60 dB the noise generated is equivalent to that of a washing machine. "And electricity is much cheaper than diesel fuel," adds Bos who is now dealing with "dozens of requests" to produce more e.PPUs.

Following his visit to China, Japan and Korea last autumn, ITER Director-General Pietro Barabaschi continued his tour of ITER stakeholders with a two-day visit to India on 5-6 February. Accompanied Sriram Kattalai Ramachandran, head of the ITER Office of the Director-General, Mr Barabaschi started off his visit in Mumbai by meeting with the Chairman of the Indian Atomic Energy Commission and Secretary to the Government of India Ajit Kumar Mohanty, followed by a visit to Larsen & Toubro's design and R&D laboratories. (Larsen & Toubro manufactured the ITER cryostat under contract with ITER India.) The following day in Ahmedabad, Gujarat, the ITER Director-General gave a presentation, followed by a question-and-answer session, to the staff of ITER India and the Institute for Plasma Research. His brief stay in Ahmedabad was also the occasion to visit the ITER India laboratory hosting the ITER radiofrequency source testing facility. Accompanied Sriram Kattalai Ramachandran, head of the ITER Office of the Director-General, Mr Barabaschi started off his visit in Mumbai by meeting with the Chairman of the Indian Atomic Energy Commission and Secretary to the Government of India Ajit Kumar Mohanty, followed by a visit to Larsen & Toubro's design and R&D laboratories. (Larsen & Toubro manufactured the ITER cryostat under contract with ITER India.) The following day in Ahmedabad, Gujarat, the ITER Director-General gave a presentation, followed by a question-and-answer session, to the staff of ITER India and the Institute for Plasma Research. His brief stay in Ahmedabad was also the occasion to visit the ITER India laboratory hosting the ITER radiofrequency source testing facility.

The third edition of the Tritium School will take place in Marseille, France, from 18 to 22 March 2024. Organized by the TITANS Project, which strives to improve tritium management and knowledge to meet the growing demand for nuclear energy, it is organized around four days of invited lectures and contributed talks, and a fifth day comprising a visit to the ITER site.The young generation of researchers working in fusion and fission research and development is encouraged to participate.Topics for discussion will include tritium management, inventory and control; waste; radiotoxicity/ecotoxicity; epidemiology of tritium; and tritium dosimetry.For all information, and to register, see this webpage. The School will be conducted in English.

If your PhD was awarded after 1 January 2021—or you are about to obtain one—you are eligible to apply for a Monaco-ITER Postdoctoral Fellowship. The Fellowship Program is recruiting now for two-year terms beginning autumn 2024. Since 2008, 39 young scientists and engineers have been able to participate directly in ITER, working on cutting-edge issues in science and technology with some of the leading scientists and engineers in each domain. The principal aim of the Research Fellowships, which are funded by the Principality of Monaco, is the development of research excellence in fusion science and technology within the framework of ITER. The deadline for application is coming up (29 February 2024). See all information here.