european monster

JET, the Joint European Torus, is the largest nuclear fusion experimental reactor yet built.

The reactor is situated on an old Navy airfield near Culham, Oxfordshire, in the UK: the construction of the buildings which house the project was undertaken by Tarmac Construction, starting in 1978 with the first experiments beginning in 1983.

JET is equipped with remote handling facilities to cope with the radioactivity produced by Deuterium-Tritium (D-T) fuel, which is the fuel proposed for the first generation of fusion power plants. Pending construction of ITER, JET remains the only large fusion reactor with facilities dedicated to handling the radioactivity released from D-T fusion. The power production record breaking runs from JET and TFTR used 50-50 D-T fuel mixes.

During a full D-T experimental campaign in 1997 JET achieved a world record peak fusion power of 16 MW which equates to a measured Q of approximately 0.7. Q is the ratio of fusion alpha heating power to input heating power, a self-sustaining nuclear fusion reaction would have an infinite Q value (requiring no external heating). In order to achieve a burning plasma, a Q value greater than 1 is required. This figure does not include other power requirements for operation, most notably confinement. A commercial fusion reactor would probably need a QJT-60 tokamak, however this was not achieved under real D-T conditions but estimated from experiments performed with a pure Deuterium (D-D) plasma. Similar extrapolations have not been made for JET, however it is likely that increases in Q over the 1997 measurements could now be achieved if permission to run another full D-T campaign was granted.

In December 1999 JET's international contract ended and the United Kingdom Atomic Energy Authority (UKAEA) then took over managing the safety and operation of the JET facilities on behalf of its European partners. From that time (2000), JET's experimental programme was then co-ordinated by the European Fusion Development Agreement (EFDA) Close Support Unit.

JET operated throughout 2003 culminating in experiments using small amounts of tritium. For most of 2004 it was shut down for a series of major upgrades increasing total available heating power to over 40 MW, enabling further studies relevant to the development of ITER to be undertaken. In the future it is possible that JET-EP (Enhanced Performance) will further increase the record for fusion power.

In late September 2006, experimental campaign C16 was started. Its objective is to study ITER-like operation scenarios.

Image: EFDA-JET (+)