With a plasma volume of 160 m3, JT-60SA is the largest tokamak in the world, a status it is expected to maintain until the start of ITER operations.
This record was officially confirmed on 04 September, and will be marked by a certification ceremony in Naka on 19 October.
Size matters for tokamaks, because creating conditions that are relevant for fusion such as high temperature and high density and maintaining those conditions in the plasma core is more feasible with a bigger device.
The status of JT-60SA as the world’s largest tokamak was already acknowledged during the JT-60SA Inauguration Ceremony on 01 December 2023, when a certificate was awarded to mark JT-60SA inheriting this crown from JET (100m3) (watch here). When it comes to superconducting tokamaks, i.e. those which use superconducting magnets to sustain plasma for long periods without consuming excessive power, the difference between JT-60SA and the second largest tokamak is even greater – JT-60SA is in a class of its own.
In 2024-2025, JT-60SA is undergoing a major upgrade to its heating systems, in-vessel components and plasma diagnostics. When operations restart it will not only be big but a lot more powerful too.
Read the press release by QST / F4E here