JT-60SA upgraded and ready for restart

The project team for the world's largest operational tokamak, JT-60SA, has announced that it is getting ready to resume operations. The machine has been undergoing upgrades since 2024, with testing of newly installed equipment occurring since February 27.

JT-60SA, located at the Naka Institute for Fusion Science and Technology of the National Institutes for Quantum Science and Technology (QST) in Naka, Japan, is a joint project between Japan and Europe.

According to QST, the team has been using "novel artificial intelligence and computational techniques" to prepare experiments that will accelerate the starting plasma phase.

Upgrades include a new first wall and divertor made with carbon-based armor and new in-vessel plasma control coils. The team installed ports for supporting systems and eight neutral beam tanks.

New diagnostics include edge Thomson scattering to measure the temperature and density of electrons in the outer region of the plasma; a vacuum ultraviolet divertor spectrometer to detect and measure impurities in the plasma; and an X-ray imaging crystal spectrometer system to measure temperature, speed, and direction of flow of the plasma particles as well as the density of particles that can cool the plasma.

"We included diagnostics and cryopumps from Europe, as well as additional heating systems, key to achieving hotter, more powerful plasmas," new JT-60SA project leader Jerónimo García said in February.

The team has planned a round of plasma heating experiments, expected to begin at the end of the year and run for around six months.

According to the European Union's Fusion for Energy program, "The operations will push the machine to unprecedented levels of current, advancing towards long-pulse and steady-state plasma scenarios. Currently, the experiment team is defining the strategy and reviewing over 150 proposals by scientists from Europe, Japan, and ITER Organization."

Former JT-60SA project leader Sam Davis added, "JT-60SA is emerging as a unique global facility and will have a critical role in preparing the next generation of fusion operators and researchers."