Announced over half a century ago, nuclear fusion is about to become reality… Within a few years – or decades – man should be able to reproduce, here on Earth and in a controlled manner, the reaction that gives the Sun its energy, thereby opening the way to production of abundant, clean and safe energy. What are the characteristics of nuclear fusion? Who are the main players and what are their challenges?
A demanding process for an ideal source of energy
While the fusion principle is simple – combine two nuclei of light atoms to release a significant amount of energy – the reality is quite different due to extraordinary constraints. Today researchers, scientists, universities, investors and governments around the world are competing relentlessly with plasma, this fourth state of matter which must be achieved (at a temperature of 100 million degrees Celsius) to allow atoms to lose their electrons, and which must be maintained for fusion to be triggered. They want to be the first to offer this new energy, which can only be praised: unlimited presence in nature of fusion fuels (such as deuterium), no CO2 emission, the main waste being helium, constant electricity supply, no need for storage…
Tokamak vs. Stellerator
No, these are not war cries…, but two reactors designed to confine the plasma and create a net gain of electricity – currently tokamaks consume more energy that they create. There is a real competition between these two main players. The tokamak, invented in Russia during the 1950s, is the reactor chosen by Iter, a nuclear facility comprising 35 countries located in the south of France. Its most recent record achievement is having circulated plasma at 50 million degrees Celsius for 102 seconds. The crucial next step of continuation of the events is triggering fusion (planned for 2035). Meanwhile the Stellerator, creator of stars, has returned to the race after studying for 20 years the ideal shape the magnetic field needs to take to confine the plasma. Its record is 100 million degrees Celsius for 1 single second, the plasma particles having crossed the magnetic field. The impermeability of the magnetic field is therefore on the agenda for this German company…
Opposing projects
Nuclear fusion arouses interest where it is not necessarily expected… If you have the most powerful laser in the world (500 terawatts) it may seem legitimate to want to use it to provoke fusion. By manipulating this laser on a target containing fuel, the National Ignition Facility succeeded in provoking fusion. The result was the appearance of a 50 micron star for one trillionth of a second, but most importantly… energy! But first of all researchers have to deal with many unexpected reactions between the laser and the plasma. Some of them – such as Michael Delage (General Fusion) – do not have delusions of grandeur, quite the contrary! This Canadian entrepreneur has joined forces with major players in the race to nuclear fusion with a simple 3 metre diameter reactor and a $30 million budget, compared to the 28 metres diameter and $25 billion for the Iter. Like the others, he is convinced that his approach is the best!
At the beginning of the twenty-first century, the question is no longer to know if nuclear fusion will become a reality, but whether deadlines will finally be met. After a postponement of 10 years for the first plasma experiment for Iter (2015 to 2025), can we expect to have the first commercial reactor in service by 2050 as planned?