JT-60 is a typical Tokamak with a D-shaped poloidal cross-section, similar to JET. Experimental results obtained by the reactor will no doubt be of great importance to the ITER experiment.
During Deuterium (D-D fuel) plasma experiments in 1998 plasma conditions were achieved which would, if the D-D fuel were replaced with a 50-50 mix of Deuterium and Tritium (D-T fuel), have exceeded break-even - the point where the power produced by the fusion reactions equals the power supplied to operate the machine. JT-60 does not have the facilities to handle Tritium; currently only the JET tokamak has such facilities. In fusion terminology JT60 achieved conditions which in D-T would have provided Q=1.25 where Q is the ratio of fusion power to input power. A self-sustaining nuclear fusion reaction would need a value of Q that is greater than 1.
On May 9, 2006 the Japan Atomic Energy Agency (JAEA) announced that the JT-60 had achieved a 28.6 second plasma duration time beating its own previous record of 16.5 seconds which it set in 2004. The JAEA used new parts in the JT-60, having improved its capability to hold the plasma in its powerful toroidal magnetic field. The main future objective of JT-60 is to realize high-beta steady-state operation in the use of reduced radio-activation ferritic steel in a collision-less regime.
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