In the fifty years that research on nuclear fusion has been carried out, enormous scientific and technological progress has been made. Fusion scientists now manipulate plasmas of hundreds of millions of degrees, in fusion devices on an industrial scale.
The figure on the right shows the progress of the so-called "triple product", a figure-of-merit which measures the performance of a fusion plasma. The triple product has seen an increase of a factor of 10.000 in the last thirty years, and another factor of 6 is needed to arrive at the level required for a power plant. In the figure, the progress is compared to that of computer chips.
The Joint European Torus - JET
JET, based in Culham, Great Britain, is the central research facility of the European Fusion programme. The focusing of significant European fusion research funding on JET has made it the pre-eminent fusion facility in the world and allowed Europe to take major strides in fusion research. JET is complemented by a number of specialized smaller devices run by more than twenty individual EU member states. The largest tokamak experiments outside Europe are the Japanese tokamak JT-60 and the American TFTR device in Princeton.
JET was approved in 1974, began operations in 1983, and met its planned operational goals on schedule in 1990. Since then, a new scientific programme has started, and JET now serves as a research facility hosting a large number of international research efforts.
JET has produced significant fusion power in deuterium/tritium plasmas - up to 16 MW - in the short pulses characteristic of existing experimental devices. "Break-even" conditions, where the fusion output power equals the external input power required to heat the plasma, were almost reached. Moreover, JET has demonstrated that fusion devices can be operated safely with tritium fuel and that radioactive structures can be maintained and modified using remote handling techniques.