The International Thermonuclear Experimental Reactor (Iter) under construction at Cadarache in southern France could be more than a decade behind schedule and is likely to need an additional €4bn ($4.6bn) in contributions, Iter director-general Bernard Bigot told Les Echos on 3 May. He said earlier plans, which expected first plasma by 2020 and full fusion by 2023, were "totally unrealistic". Bigot, a former chairman of France’s Commissariat à l’Energie Atomique et aux Energies Alternatives (atomic and alternative energy commission – CEA), said around €14-15m was the current estimated construction cost of the project. Iter was launched it 10 years ago with a cost estimated at €5bn. Bigot does not expect to see the first test of super-heated plasma before 2025 or first full-power fusion before 2035. In June, an ITER board meeting is set to review the new deadlines, which Bigot said were considered ambitious by independent experts.

Last year, the European Parliament’s budgetary control committee criticised the Iter headquarters for "delayed disbursements and growing budget costs". Europe is contributing almost half of the costs of its construction, while the other six members of the joint international venture (China, India, Japan, South Korea, Russia and the US) contribute equally to the rest.

However, an independent review of the project concluded it is "heading in the right direction" with a "sound, realistic and detailed proposal" for schedule and associated costs up to first plasma, which will be tabled at the next Iter Council meeting in June. The Council (governing body) said in a statement the independent review had concluded that major restructuring has resulted in "substantial improvement in project performance, a high degree of motivation, and considerable progress during the past 12 months". The new schedule and resource estimate for the Iter Organisation provides "a good starting point" for a revised schedule based on credible estimates of cost and human resources.