JT-60SA

JT-60SA (JA Super Advanced) is a superconducting tokamak located at the National Institutes for Quantum Science and Technology (QST) in Naka, Japan. The project is a bilateral collaboration between Japan and the European Union, with Japan providing the tokamak device and Europe providing the superconducting magnet system and other components. The project builds on the legacy of the original JT-60 tokamak, which operated from 1985 to 2008 and achieved record plasma parameters.

JT-60SA achieved first plasma on October 23, 2023, marking a major milestone for the international fusion program. The device is the largest superconducting tokamak currently in operation, with a plasma major radius of 2.96 meters and a plasma minor radius of 1.18 meters. The superconducting magnet system uses niobium-titanium conductors and allows sustained plasma operation for periods of up to 100 seconds.

The primary mission of JT-60SA is to support ITER and contribute to the design of DEMO (the demonstration power plant that will follow ITER). Key research objectives include:

• Establishing the physics basis for ITER operation, particularly for high-beta steady-state scenarios
• Developing operational scenarios for ITER that maximize fusion performance
• Contributing to DEMO design by demonstrating long-pulse operation with high fusion gain
• Studying plasma-wall interaction and exhaust management with metallic plasma-facing components
• Validating predictive models for plasma confinement and stability

JT-60SA is designed to operate with deuterium plasma (not tritium), so it will not achieve significant fusion power production. However, the physics results from JT-60SA can be extrapolated to ITER and DEMO conditions using established scaling laws. The device can also test operational scenarios and control systems that will be needed for ITER.

The European contribution to JT-60SA includes the 18 superconducting toroidal field coils, built by a consortium of European companies, and various diagnostic systems. This collaboration represents a significant European investment in the Japanese fusion program and strengthens the EU-Japan fusion partnership. The collaboration also provides European fusion researchers with access to a major superconducting tokamak facility during the period between JET decommissioning and ITER operation.

JT-60SA connects to the broader international fusion program through its role as an ITER satellite tokamak. Along with KSTAR (Korea), EAST (China), and other superconducting tokamaks, JT-60SA provides the experimental data needed to validate ITER operational scenarios and reduce technical risk before ITER begins operation.