The Joint European Torus (JET) is the largest Tokamak experiment operating in the world. Its design was started in September 1973, by a team of.engineers and physicists, assembled from throughout Europe at Culham, near Abingdon, United Kingdom. After the design work was completed, approval for construction was given in 1978 and the JET Joint Undertaking was established and the Construction Phase started in June 1978. The basic machine and its major subsystem were completed on time and within costs in June 1983, when the Operation and Development Phase began.