Japan’s National Institutes for Quantum Science and Technology (QST) announced that the JT-60SA tokamak generated its first plasma in October 2023, marking the successful commissioning of the world's largest operational superconducting fusion reactor. The achievement is the culmination of a multi-year upgrade to the original JT-60 device, a joint project between Japan and the European Union under the Broader Approach Agreement. This milestone validates the complex integration of its advanced magnet systems, vacuum vessel, and control architecture, positioning the device as a critical testbed for next-generation fusion technologies. The successful plasma initiation signifies the start of the device's operational phase, which will focus on generating physics and engineering data essential for future fusion power plants. Source: ITER

JT-60SA serves as a satellite tokamak for the International Thermonuclear Experimental Reactor, designed to investigate advanced operating scenarios and test technologies under conditions relevant to a power-producing reactor. Its primary mission is to sustain high-pressure, high-temperature plasmas for extended durations, aiming for pulses of up to 100 seconds. This capability will provide invaluable data on plasma stability, control, and heat exhaust management, directly informing ITER's operational strategies. The device's superconducting magnet system, composed of both toroidal and poloidal field coils, is engineered to confine a plasma volume of 135 cubic meters. The successful first plasma demonstrates the functionality of these integrated systems, a significant step in de-risking similar technologies for ITER and subsequent demonstration power plants (DEMO). Source: ITER

Its primary mission is to sustain high-pressure, high-temperature plasmas for extended durations, aiming for pulses of up to 100 seconds.

The project represents a significant international collaboration in fusion research, managed jointly by QST in Japan and the European agency Fusion for Energy (F4E). This partnership leverages shared expertise and resources to accelerate fusion development, a model of international cooperation central to the field. The upgrade from the original JT-60, which operated with resistive copper magnets, to the superconducting JT-60SA involved a complete overhaul of the machine's core components. This included the installation of 18 niobium-titanium toroidal field coils and a central solenoid, enabling the long-pulse, high-performance operations that were not possible with the previous configuration. The successful commissioning of these complex, cryogenically cooled systems is a major engineering accomplishment for the global fusion community. Source: ITER

With first plasma achieved, the JT-60SA research program will now proceed through a series of staged operational campaigns. Initial experiments will focus on characterizing the plasma and commissioning diagnostic systems. Subsequent phases will increase plasma current, heating power, and pulse duration to explore advanced tokamak physics regimes. The data gathered will be critical for validating plasma confinement models, testing divertor concepts for handling intense heat fluxes, and optimizing scenarios for stable, long-duration operation. The operational experience gained on JT-60SA will directly support the commissioning and operational phases of ITER, providing a trained workforce and tested procedures for managing a large-scale superconducting tokamak. Source: ITER