International nuclear fusion project may be delayed by years, its head admits

Facility in France still far from being able to show feasibility of generating carbon-free energy despite recent breakthrough in US

An international project in nuclear fusion may face years of delays, its boss has said, weeks after scientists in the United States announced a breakthrough in their own quest for the coveted goal.

The International Thermonuclear Experimental Reactor (Iter) project seeks to prove the feasibility of fusion as a large-scale and carbon-free source of energy.