JT-60
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JT-60 (JT stands for Japan Torus) is the flagship of Japan's magnetic fusion program, run by the Japan Atomic Energy Research Institute (JAERI), and the Naka Fusion Research Establishment in Ibaraki Prefecture, Japan. In operation since 1985, it currently holds the record for the highest value of the fusion triple product achieved (
). 1.
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.
