Joint European Torus

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The JET experiment hall in 1991. The toroidal plasma vessel enclosed by the orange magnetic field coils is surrounded by measuring devices and heating systems. The two people in the middle below give an impression of the size of the experiment.

Joint European Torus ( JET ) is a Europe-wide jointly operated test facility in Culham ( Great Britain ) for the development of tokamak- type nuclear fusion reactors . JET is currently the world's largest experiment based on the principle of magnetic confinement and has almost reached the ignition condition . The follow-up project ITER is based on the plasma heating, diagnostics and modeling methods developed with JET .

history

In 1973, the members of the European Atomic Energy Community decided on a joint project to implement nuclear fusion. Culham in England was set as the location in 1977 and construction began. The operating company JET Joint Undertaking was founded in 1978. On June 25, 1983, JET began experimental operations. Queen Elizabeth II officially inaugurated the facility on April 9, 1984. The first director was Hans-Otto Wüster (until 1985), followed by Paul-Henri Rebut (1985 to 1992), Martin Keilhacker (1992 to 1999), Jean Jacquinot (1999), Jérôme Paméla (2000–2006) and Francesco Romanelli (2006 –2014).

The research at JET was in competition with the US TFTR project at Princeton University . On November 9, 1991, the first notable successes in energy generation by means of nuclear fusion were recorded. It was possible to create an energy-supplying plasma for two seconds - the first controlled nuclear fusion in history. This resulted in an output of 1.8 megawatts with a deuterium - tritium mixture ratio of 86:14 . After a divertor developed according to the latest findings was retrofitted in 1993 , a fusion power of 16 megawatts could be achieved in 1997 with a mixing ratio D: T 50:50, as is intended for future reactors, about 2/3 of the coupled heating power. At the end of the nineties, the development of remote-controlled operating systems [eng. Remote Handling], a technology that will be indispensable for future fusion reactors.

Between 2000 and 2014, JET's scientific program was coordinated under the European Fusion Development Agreement , which merged into EUROfusion as part of a reorganization of the European fusion program . With the entry into force of the eighth research framework program Horizon 2020 , JET's scientific orientation is now being coordinated by EUROfusion, while a bilateral contract between EURATOM and the JET host Culham Center for Fusion Energy (CCFE) regulates the operational business.

Under Horizon 2020, JET is funded with 283 million euros for the period from 2014 to 2018 [obsolete] . The exit from the European Atomic Energy Community EURATOM announced by the British government at the beginning of 2017 unsettled the researchers. It is hoped that further participation in EURATOM, either as a third country such as the USA or as an associate member such as Switzerland, as well as an extension of the contract between EURATOM and the Culham Center for Fusion Energy (CCFE) beyond 2018.

Technical specifications

The tokamak has a diameter of around 15 m and a height of 12 m. The ring-shaped vacuum vessel has a D-shaped cross-section 4.2 m high and 2.5 m wide, an outer diameter of 8.4 m and a volume of 200 m 3 . The plasma magnetically enclosed therein has a large radius (see torus ) of 2.96 m, an average small radius of 1.5 m, a volume of 80 to 100 m 3 and a mass of less than a tenth of a gram. The iron core for coupling the current in the central coil with the current in the plasma, up to 5 mega amps , weighs 2800 tons and consists of eight rectangular frames with a common central limb. 32 D-shaped coils generate the toroidal magnetic field of up to 4 Tesla for the confinement and require 250 megawatts of electrical power during the burning phase of a plasma pulse, another 250 MW are shared by the various devices for generating plasma current and temperature, with the current being mainly the Stabilization of the plasma serves, but also contributes a few megawatts to heating. Greatest heating source is the neutral injection system (Neutral Beam Injection System) (net to 34 megawatts), followed by ion cyclotron resonance heating (Ion Cyclotron Resonance Heating, 10 MW) and the Lower Hybrid Current Drive (up 7 MW) of drives the current through traveling waves. For mergers, the power consumption is significantly higher, especially for the Poloidal Field system, which is therefore fed by two flywheel accumulators, each weighing 775 tons. The pulse duration is limited by the rapid heating of the copper coils and is 20 to 60 seconds, depending on the desired field strength. The breaks last 15 minutes, during which the heat is transported to cooling towers via cooling circuits (4 × 35 MW) and the flywheel storage is charged (2 × 8 MW). The circulation pumps consume more energy than is released by nuclear fusion. The power amplification factor Q is 0.65.

Web links

Commons : Joint European Torus  - collection of images, videos and audio files
  • EUROfusion Homepage: JET

Individual evidence

  1. ↑ About JET's startup . (euro-fusion.org)
  2. ↑ http://www.efda.org/jet/history-anniversaries/ ( Memento from October 4, 2014 in the Internet Archive )
  3. ^ Paul-Henri Rebut: JET's first plasma . (euro-fusion.org)
  4. ^ JET directors . (euro-fusion.org)
  5. ↑ Elizabeth Gibney: Researchers shocked at UK's plan to exit EU nuclear agency . Nature News, January 27, 2017, doi: 10.1038 / nature.2017.21388 .
  6. ↑ EUROfusion statement on Brexatom . (euro-fusion.org)
  7. ↑ Official website, main features
  8. ↑ Focus on JET (PDF)
  9. ↑ https://www.euro-fusion.org/2014/01/comparison-of-jet-and-iter/

Coordinates: 51 ° 39 '33 "  N , 1 ° 13' 35"  W.