Nuclear fusion is an area for which a wide variety of know-how and state-of-the-art technology is required. For that very reason fusion research is bound to happen internationally.
Due to its excellent confinement properties, the tokamak is presently the most succesful type of fusion machine. Since its inception in 1968, the tokamak has known a steep curve of improved performance. The figure on the left shows the progress of the triple product of the density, temperature and confinement time. This quantity was proposed by Lawson as the figure of merit for fusion in 1957; the criterium he derived is now referred to as the "Lawson" criterium. For comparison, the progress in the computer processor industry and that in accelerator research are provided. It is readily noted that the progress in tokamak performance is faster than either of the other two. Roughly every 1.8 years, tokamaks become twice as powerful. At the top right end of the curve, one finds the high-performance tokamaks: JET (EU), TFTR (USA; operational program suspended in 1997 and dismantled shortly afterwards) and JT-60U (Japan). After JET having shown that near-megawatt levels of fusion power could be generated from fusion in 1991, TFTR demonstrated its capacity to improve this performance and produced 10MW of power in its 1994 experimental campaign. The present record is held by JET. It produced up to 16MW of fusion power during a short, dedicated D-T campaign in 1997. This is about 60% of the power that was required to initiate the fusion processes. A necessary condition for an experimental reactor to become an actual power plant is that it is capable to produce more energy than it consumes, i.e. that the multiplication factor exceeds 1 ("break-even"). The next step ITER machine is designed to run at an energy multiplication factor of about 10. Commercial fusion power stations will be "ignited": As the heat captured from the energetic alpha particles that are formed by the fusion reactions will be sufficient to keep the temperature in the required range for the fusion reactions to happen spontaneously as long as fuel is added, these machines will no longer need the auxiliary heating mechanisms to heat the plasma but only to help controlling the plasma stability once the fusion processes have been initiated.
The table below provides some of the key parameters of some machines of the tokamak type.
The list below is a non-exhaustive list of international partners participating in the fusion research program.
- Alfvén Laboratory (Stockholm, Sweden)
- CEA (Cadarache - France) http://www.cad.cea.fr
- Chalmers (Göoteborg, Sweden) http://www.elmagn.chalmers.se
- CIEMAT (Madrid - Spain) http://www.ciemat.es/eng
- Consorzio RFX (Padova - Italy) http://www.igi.pd.cnr.it
- CRPP - EPFL (Lausanne - Switzerland) http://crppwww.epfl.ch
- ENEA (Frascati - Italy) http://ftu.frascati.enea.it
- ENEA - CNR (Milano - Italy) http://www.ifp.cnr.it
- FIRE (Princeton, USA) http://fire.pppl.gov
- FOM-Rijnhuizen (Utrecht, The Netherlands) http://www.rijnh.nl
-GA (San Diego, USA) http://fusioned.gat.com
-IPP-FZJ (Jülich, Germany) http://www.fz-juelich.de/ipp
- IPP-MPG (Garching, Germany) http://www.ipp.mpg.de
- JAERI (Naka, Japan) http://www.jaeri.go.jp/english/index.cgi
- JET-EFDA (Culham, United Kingdom) http://www.jet.efda.org
- Kurchatov - Fusion (Moscow, Russia) http://www.kiae.ru
- LANL (Los Alamos, USA) http://lanl.gov
- LPP-ERM/KMS (Brussels, Belgium) http://fusion.rma.ac.be
- ORNL (Oak Ridge, USA)http://www.ornl.gov/ornlhome/science_technology.htm
- PPPL (Princeton, USA) http://www.pppl.gov
- PSFC-MIT (Boston, USA) http://www.psfc.mit.edu
- SPP-ULB (Brussels, Belgium) http://www.ulb.ac.be/sciences/spp
- TEKES (Helsinki, Finland) http://www.tekes.fi
- UKAEA - Culham (Culham, United Kingdom) http://www.fusion.org.uk