Fusion for Energy (F4E) is the body of the European Union (EU) that is responsible for the EU's contribution to the International Thermonuclear Experimental Reactor (ITER), the world's largest scientific partnership aiming to demonstrate fusion as a viable and sustainable source of energy. The organisation is officially named European Joint Undertaking for ITER and the Development of Fusion Energy and was created under article 45 of the Treaty establishing the European Atomic Energy Community by the decision of the Council of the European Union on 27 March 2007 for a period of 35 years.F4E counts 450 members of staff. Its seat is located in Barcelona, Spain, and it has offices in Saint-Paul-lès-Durance, France, and Garching, Germany. One of its main tasks is to work together with European industry and research organisations to develop and provide a wide range of high technology components for the ITER project.
JT-60SA is the world's largest superconducting tokamak in operation jointly built and exploited by Europe and Japan in the framework of the Broader Approach. JT-60SA aims at addressing some of the technological and physics challenges, such as the long pulse steady-state plasma operation at high beta. The start-up of JT-60SA, which culminated in the first JT-60SA plasma achieved on 23 October 2023 and Operation-1 (OP-1) until the end of 2023, including the achievement of >1 MA diverted plasmas, paves the way for a new generation of large superconducting tokamaks, such as ITER. Several key scientific topics were investigated during this initial phase. Similarly to ITER, the available parallel electric field (E-||) is low and yet plasma initiation was quickly obtained by means of the trapped particle configuration (TPC) with the assistance of similar to 1.5 MW of electron cyclotron resonance heating (ECRH). A first analysis and classification of the causes for disruptions have been done after the results of OP-1. Vertical displacement events (VDEs) were responsible for the vast majority of disruptions in increasing elongated plasmas, as the stabilization plate was not yet installed in this phase. Therefore, VDE predictors and control algorithms were developed using machine learning techniques with magnetics probe data, showing that these novel techniques are also suitable for the start-up tokamak phases characterized by scarce input data. JT-60SA will restart operation in 2026 following a series of upgrades. The experimental programme for future operations is guided by significant modelling 'predict first' activity, which shows that access to and development of H-mode in conditions of future burning plasmas will be possible with high negative neutral beam injection (N-NBI) and ECRH input power. The integration of such elements into a steady-state long pulse operation will be done with the installation of W plasma facing components (PFC) after the initial campaigns.
The fully superconducting tokamak JT-60SA achieved its first plasma already during the first operational campaign (OP-1) in 2023. To obtain this result, a suitable operation procedure of magnet system, temperature and coil current control was essential. During the same operational campaign, OP-1, JT-60SA was able to generate a diverted plasma with 1.2 MA of plasma current. However, the PF coil current was limited to 5 kA during this operational campaign with respect to a maximum current up to 10 kA tested during the single coil excitation test performed before the plasma experiments. In the next operational campaign OP-2, nominal current (20 kA) operation will be demonstrated for the PF coil system, so they can fulfill their purpose of producing high-performance plasmas. Aiming at this, various improvements were considered for safe energization and protection of the coils.
The ITER bolometer diagnostic employs a miniaturized metal resistor bolometer configured in a Wheatstone bridge to detect the incoming plasma radiation. Due to the harsh radiation environment, the acquisition system must be located remotely, requiring a long transmission line between the sensor and the electronics. To avoid low-frequency noise affecting the signal integrity, the bolometer input is modulated and the signal is recovered via synchronous in-phase and quadrature demodulation. However, the transmission line introduces frequency-dependent distortion that affects the demodulation accuracy and power estimation. This article presents a method to compensate for such distortion by exploiting the harmonic content of a square-wave modulation. By extracting the amplitudes of the first and third harmonics and comparing them to their ideal ratio, the frequency response of the transmission line can be identified in real time. This enables online compensation for dynamic changes in the transmission line characteristics and broadens the possible modulation frequency range. The proposed approach is validated through a real-time implementation using a 100-m-long cable, showing improved accuracy in estimation performance.
The ITER Pre-Compression Ring system provides the radial preload required to maintain structural integrity and coil-to-coil contact in the Toroidal Field magnet assembly. Each of the six 5.6 m fiberglass-reinforced composite rings operates at 4.2 K under sustained load for 20 years. Given the viscoelastic nature of fiber composites, two long-term phenomena are of concern: stress relaxation, which could reduce preload, and creep rupture. Earlier studies demonstrated that preload relaxation stabilizes quickly and does not threaten performance. However, initial assessments of creep rupture, based on conventional stress-rupture curves and extrapolated strength degradation, predicted a reduction in safety margins to levels below the design target, though not necessarily resulting in failure. To address this conservatism, a revised testing program focused on residual strength after sustained loading. Small-scale uniaxial tests were conducted by CERN (up to 5000 hours at room temperature), while ENEA carried out multiaxial tests on 1:5-scale PCR mock-ups. All results showed no measurable degradation, confirming that the composite rings can retain adequate mechanical performance for the full 20-year operational lifetime.
The Tokamak Systems Monitor (TSM) software will provide ITER operators with timely assessments of machine health, component lifetime, and early warnings of potential faults. Among its key functions, the TSM will employ data-driven anomaly detection methods to identify unexpected or abnormal behavior across a broad range of systems and diagnostics. This work presents an initial proof-of-concept for anomaly detection applied to gyrotron pulses, leveraging data from the European gyrotron prototype. The method combines dimensionality reduction and clustering techniques to identify deviations from expected operational patterns. This approach enables the detection of subtle anomalies that might otherwise go unnoticed. While this first demonstration focuses on intershot anomaly detection for gyrotrons, the methodology is designed to be adaptable to other systems and signals within the TSM, contributing to the improved maintenance strategies and reliability of the ITER tokamak.
