The European Union and six states backing a multi-billion-dollar nuclear fusion project said Wednesday they had reached a deal on the financing and timetable for the experimental reactor.
An explosion in costs had cast a cloud over the International Thermonuclear Experimental Reactor (ITER), which aims to make the nuclear fusion process that fuels the sun a practical energy source on Earth.
ITER, based at Cadarache in southern France, was set up by the EU, which has a 45 percent share, China, India, South Korea, Japan, Russia and the US to research a clean and limitless alternative to dwindling fossil fuel reserves.
ITER's governing council reached the deal after a two-day meeting in Cadarache at which Europe pledged to provide additional financing of a maximum 6.6 billion euros (8.5 billion dollars), it said in a statement.
It also formalised a decision to abandon its goal of 2018 to obtain the first plasma and set November 2019 as its new target.
Nuclear fusion entails forcing together the nuclei of light atomic elements in a super-heated plasma, held in a doughnut-shaped chamber called a tokamak, so that they make heavier elements and in so doing release energy.
"We are now entering a decisive phase in the ITER project," said Evgeny Velikhov of the ITER governing council.
The meeting also named Japanese physicist Osamu Motojima as ITER's new director-general, to replace his compatriot Kaname Ikeda.
The total estimated bill for the EU has doubled to 7.2 billion euros (9.2 billion dollars), with the overall cost now reckoned to be around 15 billion euros.
Explore further: Nuclear experts seek to advance ITER fusion project