The ITER 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.
Over the next few years about a million individual components of the highly complex fusion reactor will arrive at the Cadarache site from around the world. They will be assembled like a giant Lego model in a nearby building which has a volume equal to 81 Olympic-sized swimming pools.
The roots of the Iter project go back to 1985 when Mikhail Gorbachev, General Secretary of the former Soviet Union, offered his country’s prowess in nuclear fusion as a bargaining chip in the nuclear disarmament talks with the US, which at that time was pursuing its “Stars Wars” defence system.
Gorbachev and President Reagan, with the support of Margaret Thatcher and French President François Mitterand, signed an agreement to cooperate on nuclear fusion using the Russian “tokamak” reactor. This was a revolutionary device that could hold the super-hot fusion fuel by creating a “magnetic bottle” within the reactor’s doughnut-shaped vacuum vessel.
Several experimental tokamak reactors around the world, including one at the Culham Centre for Fusion Energy in Oxfordshire, have shown nuclear fusion is theoretically possible, but the giant tokamak at Iter will be the first to generate more power than it needs to attain the very high temperatures required for nuclear fusion.
IF it was successful the ITER fusion project would deliver an inferior result to deep burn fission. The Integral Molten Salt reactor is an example of a system that would deliver lower cost energy by the 2020s. It would cost less and has far lower technical hurdles and would provide clean power at lower cost over 30 years faster than ITER
The Iter tokamak machine, which is twice the linear size and 10 times the volume of its nearest rival at Culham, will produce temperatures of well over 100 million C – many times hotter than the centre of the Sun.
It is the first experimental fusion reactor to receive a nuclear operating licence because of its power-generating capacity. For every 50 megawatts of electricity it uses, it should generate up to 500mw of power output in the form of heat.
Richard Pitts, a British nuclear physicist working on the project, said that even though Iter has a nuclear operator’s licence and will produce about 10 times as much power as it consumes, the Iter machine will still remain a purely experimental reactor, with no electricity generated for the French national grid. “We’re not building a demonstration industrial reactor. We’re building the first step towards one that does produce electricity for the grid. If we can show that fusion works, a demonstration reactor will be much cheaper to build than Iter,” Dr Pitts said.
A critical phase of the project will be the injection of plasma – the superhot, electrically-charged gases of the atomic fuel – into the reactor’s vacuum chamber. This plasma, a mix of the hydrogen isotopes deuterium and tritium, will drive the nuclear-fusion reaction.
The plasma will be heated to temperatures as high as 300 million C to force the atomic nuclei close enough together to cause them to fuse into helium, a harmless and inert waste product that could be recycled as an important industrial raw material. Giant electromagnets powerful enough to trap an aircraft carrier will contain the plasma within a spinning vortex held by the magnetic bottle of the tokamak reactor.
The original date for “first plasma” was scheduled for November 2020 but delays with the construction and commissioning phases have pushed this back to October 2022 – although some of that lost time has since been clawed back. One of the electromagnetic coils used in the giant magnets, for instance, had to be scrapped after a worker in one of the participating countries left a towel on one of the superconducting cables which then became compressed within a coil. Costly mishaps like this put the entire project behind schedule.
2021-22: “First plasma” scheduled, when ionised gases will be injected into the Iter tokamak.
2027-28: Iter “goes nuclear” with injection of tritium.
2030s: First demonstration fusion reactor to produce electricity for grid.
2050s onwards: First commercial nuclear fusion power plants.