Joint European Torus
Joint European Torus (JET ) is a jointly operated throughout Europe test facility in Culham ( UK ) for the development of nuclear fusion reactors of the tokamak type. JET is currently the world's largest such experiment. The project has as target various aspects of a real future fusion power plant as studying the ignition conditions of the plasma and to pave the way for the ITER project.
The members of the European Community decided in 1973, the project, after which the design work began. 1977 Culham was defined as a location in England and started construction. The foundation of the company incorporated under the JET Joint Undertaking was 1978. The first plasma in the reactor was created on 25 June 1983. Queen Elizabeth II inaugurated the facility on 9 April 1984 officially. The first director was Hans -Otto Wüster (until 1985 ), followed by Paul -Henri Rebut (1985 to 1992), Martin Keilhacker ( 1992-1999 ), Jean Jacquinot (1999), Jérôme Paméla (2000-2006 ) and Francesco Romanelli (from 2006).
The research at JET were in competition with the U.S. project TFTR at Princeton University. On November 9, 1991 the first significant achievements in energy production were recorded by means of nuclear fusion. You managed to strike a energy-producing plasma for two seconds - the first controlled nuclear fusion of history. It came with a deuterium -tritium mixture ratio 86:14 to a capacity of 1.8 megawatts. In 1993, a divertor system has been upgraded. In 1997, with a mixing ratio of 50:50, as it is planned for future reactors achieved a fusion power of 16 megawatts, about 2/3 of the coupled heat output.
In addition, in 1998 remote operation systems for tokamaks were tested, which are necessary in future reactors.
Since 2000, JET is assigned to the EFDA ( European Fusion Development Agreement ).
The successor of JET will be ITER, the 2026Vorlage: Future / to be completed in 5 years. With him for the first time to a positive energy balance can be achieved.
The tokamak has around 15 m in diameter at 12 m height. The ring-shaped vacuum tube has a D - shaped cross-section of 4.2 m height and 2.5 m in width, an outer diameter of 8.4 m and a volume of 200 m3. The fact magnetically confined plasma has a large radius (see torus ) of 2.96 m, an average minor radius of 1.5 m, a volume of 80 to 100 m3 and a mass of less than a tenth of a gram. Of the iron core for coupling the current in the central coil with the current in the plasma, to 5 Mega Ampere, whereas weighs 2800 tons and is composed of eight rectangular frame with a common central limb. 32 D- shaped coils generate the up to 4 Tesla strong toroidal magnetic field for the confinement and need during the combustion phase of a plasma pulse 250 megawatts of electrical power, an additional 250 MW share the various facilities for the generation of plasma current and temperature, the current mainly the stabilization of the plasma is used, but also contributes to several megawatts heating. Largest source of heat is the neutral particle injection system (Neutral Beam Injection System) (net to 34 megawatts), followed by the ion cyclotron resonance heating ( Ion Cyclotron Resonance Heating, 10 MW ) and the Lower Hybrid Current Drive (up to 7 MW ), the drives the current through traveling waves. For mergers, the power consumption is much higher, in particular the poloidal field system, which is therefore fed by two flywheels à 775 tons. The pulse duration is limited by the rapid heating of the copper coils, and is dependent on the desired field strength, 20 to 60 seconds. Breaks take 15 minutes, during which the heat is transported by the cooling circuits for cooling towers (4 x 35 MW ), and the flywheel can be loaded ( 2 8 × MW). The circulation pumps consume more energy than is released by nuclear fusion.