The US had been one of the four original partners in the design of ITER - along with the European Union, Japan and Russia - but pulled out in 1999 for reasons of cost. The three remaining partners continued working on the project and Canada - which had originally been involved as part of the EU team - became involved when it offered a site for ITER at Clarington near Toronto in 2001. The French, Japanese and Spanish governments have also offered sites. A decision on where to build the reactor is expected this year. Construction could begin in 2006 and the reactor would be operational in 2014.

ITER has been designed to confine a plasma of deuterium and tritium for times of up to 500 seconds, and to produce 10 times as much fusion power as is used to create and maintain the plasma. According to the DOE: “The Bush administration believes that fusion is a key element in US long-term energy plans because fusion offers the potential for plentiful, safe and environmentally benign energy.”

The US share of the construction costs is expected to be about 10%. The Chinese government has also asked ITER to be involved at this level.