Joint European Torus. The JET Joint Undertaking was established in June 1978 to construct and operate the Joint EuropeanTorus, of its time the largest single project within the European nuclear fusion programme. It was coordinated by Euratom (the European Atomic Energy Community), and the JET project went on to become the flagship of the Community Fusion Programme and the first fusion facility in the world to achieve significant production of controlled fusion power in 1991. In 1997 JET achieved more than 16 MW fusion power in Deuterium-Tritium plasmas. JET has furthered fusion science well beyond the goals of the original Design Team and is now evolving into a physics and technology basis for preparing ITER, the International Thermonuclear Experimental Reactor. Under EFDA, the European Fusion Development Agreement, a new JET Implementing Agreement has been set up to use the JET Facilities until at least the end of 2002, replacing the Joint Undertaking which came to an end on December 31st 1999.