This week the project gained final approval for the design of the most technically challenging component – the fusion reactor's "blanket" that will handle the super-heated nuclear fuel.
The building site in Cadarache has also passed the crucial stage where some 493 seismic bearings – giant concrete and rubber plinths – have been set into the reactor's deep foundations to protect against possible earthquakes.
Peering over the edge of the huge seismic isolation pit, it is still possible to see some of these bearings before they are covered with a raft of reinforced concrete that will support the massive fusion machine at the heart of the £13bn Iter project.
