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ITER NEWSLINE 45
When presenting the promises of fusion, scientists often use this image: the energy potential contained in a bathtub filled with water (45 litres) and in the lithium of one laptop battery is equivalent to 40 tons of coal, and would provide some 200.000 kw/h of electric power. Striking—but how do you get fusion fuel, namely deuterium and tritium, from water and lithium?
"Deuterium accounts for 0.016% of water and is not very difficult to obtain", explains Manfred Glugla, ITER Division Head for Fuel Cycle Engineering. "The industry does it routinely through distillation techniques." Tritium, which is a huydrogen isotope too, is continuously produced in very small quantities in the upper atmosphere, where cosmic rays interact with nitrogen.
"Tritium's total natural inventory is 4 to 7 kilograms, to which one must add some 40 kg, left over from the atmospheric nuclear tests performed during the 60's."As tritium is a fast decaying radioelement, this "artificial" inventory will be empty in a couple of decades. But the upper atmosphere is not where the tritium for ITER will come from.
There is another source of tritium: pressurized heavy water reactors, so called CANDU reactors, who use natural uranium as fuel and heavy water as moderator. In CANDUs, tritium is a by-product of the reaction and its global inventory is presently around 20 kilos. To this safely stored "waste", ITER has opened an unexpected market: "the programme will require15 to 18 kg of tritium. Twenty years of operation will eat up the world inventory", says Manfred Glugla.
When fusion enters the industrial age, the tritium demand will be considerably higher: A fusion plant will typically require 56 kg of tritium per thermal Gigawatt per year. "Considering fusion plants will be 2 to 3 GW, this means we'll need a hell of a lot of tritium!" Where to get it? In the laptop batteries—that is, in lithium, a soft, light metal, more abundant than lead which, when interacting with neutrons, converts into tritium and helium. In ITER, this process will only be tested; in fusion plants, tritium-breeding blanket modules will be among the installation's key components. "This is another of fusion's technical challenges: it will only work if we are able to produce enough tritium inside the reactors."
Boars have always been at home in the woods of Cadarache. In 1964, archaeologists digging a Bronze Age necropolis, located near what is now the CEDRA installation, came up with a most exceptional find: a tomb containing the remains of a large wild boar, two copper rings and a serpentine ritual axe-head. Boars were sacred then and in the way, they still are. "You can't dissociate boars from Cadarache, says Jean Faivre. They are the emblem of the Centre and even though they can be something of a nuisance, causing some 10 to 40 minor car accidents a year, we do our best to keep them in good health, feed them when they need it and regulate their population."
Boars are common, but mouflons are quite rare. Cadarache's herd of about 150 individuals is one of the densest in Europe, and one of the very few "genetically pure", stemming from one original group of two males and one female which were introduced to the site in 1934.
Their history is linked to a tragic historical event. These three mouflons, which had been captured in the island of Corsica, were to be offered to King Alexander I of Yugoslavia on the occasion of his State visit in France, in October of 1934. But on his arrival in Marseilles, the King was assassinated, leaving the French government with this question: What to do with the mouflons?
At the time, what is now CEA-Cadarache was under the jurisdiction of the National Forestry Commission ("Eaux et Forets") and hosted a small Game Warden Academy—the Kings' mouflons were entrusted to their care.
As for the Sika deer, "they were brought to Europe in the 19th century, now they're everywhere", says Faivre. "and in Cadarache, they compete with the mouflons for food and territory... so we have to regulate their population."
This "regulation" is essentially done through hunting. For fifty years, Cadarache's hunting parties have been an important part of the region's social life—4 such "grandes chasses" are organized every year, one of them for the local politicians, mayors, industrialists and CEA business partners, the other three for the Centre's Hunting society.
Cadarache is a unique example of a nuclear research centre doubling as a wildlife preserve—and both are thriving.