New Scientist 31 May 2017 By Andy Coghlan
THIS may resemble a distillery, but what it will generate isn’t for drinking. It will serve up streams of atoms and ions to make the energy of the sun right here on Earth through nuclear fusion.
Called SPIDER and due for completion next year, this facility in Padua, Italy, will help fine-tune what will become the key heating source for ITER, the world’s first experimental fusion reactor. ITER is under construction in southern France and due to be ready in 2025.
Within the ITER tokamak reactor – a reaction chamber shaped like a doughnut – two forms of hydrogen – deuterium and tritium – will be smashed together in a plasma to fuse and form helium atoms as “ash”, plus high-energy neutrons that can be harnessed to drive turbines.
To create the plasma, the temperature within the tokamak must be raised to 300 million°C – about 10 times the temperature of the sun – and the heat for that will come from two high-energy beams of deuterium fired simultaneously into the tokamak.
SPIDER will test how beams of deuterium atoms behave in a smaller, experimental reaction chamber, how much heat they generate and how to control the temperature within the reactor.
Pictured, top, is the labyrinthine piping network supplying the cooling system for the reactor. The brown panels resembling a sauna, in the picture below, are tiles for soaking up surplus energy from the beams. Made from an alloy of chromium, copper and zirconium, the tiles are themselves cooled by water fed through pipes visible behind the panels.
The reactor, above, is here viewed from underneath through the circular structure, and the power for the whole facility is supplied from within the gleaming silver Faraday cage seen in the picture below. If all goes to plan, ITER will use this technology to produce a lot of energy. It might not be drinkable, but it will be consumable.