The International Thermonuclear Experimental Reactor (Iter) under construction at Cadarache in southern France is more than 65% complete and entering a critical phase as it aims to meet a first plasma deadline of 2025, project head Bernard Bigot told NucNet.

First plasma means that the reactor is able to successfully generate a molten mass, 840 m3 to be exact, of electrically-charged gas, or plasma, inside its core.

For the next three years the focus is getting all main components for the fusion reactor in place, Mr Bigot said, adding that “there is a lot of pressure”. Some components weigh up to 500 tonnes and making sure they are delivered on time and fit as they should is a huge challenge.