Nuclear fusion is always in limbo – every year we’re promised the appearance of the first commercial reactor will happen in 30 years. Over the years, this number does not decrease. Controlled nuclear fusion has not approached us one iota since the idea first appeared in the 1950s. However, could be the best steps towards nuclear fusion be small reactors?
It is widely believed that the more the better when talking about nuclear fusion. Massive international experiment ITER brings this statement to the extreme, developing a reaction chamber in the shape of a donut in 20 meters in diameter and requiring 1,000 employees cycling to work. Worth its “modest” $ 50 billion.
However, experts have gradually come to the view that the less ambitious approach would bring the fruits cheaper and faster. Last month, the aerospace company Lockheed Martin said it is almost ready to build a compact nuclear fusion reactor that can be fit on the roof of a truck, just ten years later.
Tom Zharbo University of Washington in Seattle has developed its own small reactor, which, according to him, will cost less than $3 billion and could be built in the next fifteen years.
Nuclear fusion reactors promise a cheap, clean energy with a minimum of radioactive waste and risk. Reactors that develop ITER, Lockheed Martin and Zharbo, use magnets to contain a mixture of deuterium and tritium (stable isotopes of hydrogen), heated to the point where the electrons are separated from the atomic nuclei.
The magnetic field is necessary to keep the plasma hot. The isotopes merge into helium nuclei, releasing neutrons and generating a extraordinary amount of energy.
It is easier said than done, however. “Plasma Physics – it’s not rocket science – says Zharbo. – It is much more difficult. ”
One of the main objectives is to keep the chaotic plasma in place for more than a tiny fraction of a second. Reactor like ITER tried to implement this by using magnetic fields generated by a coil around the “donut”, and superconducting magnets, passing through the central hole. But it requires expensive meters and bulky shielding to protect refrigerated magnets from high-energy neutrons.
Zharbo trying to reduce the overall project, using the so-called sferomak in which plasma flowing in a current generates a magnetic field which, in turn, restricts the plasma itself elegantly. In the absence of sensitive components inside the “hole”, sferomaki can be arbitrarily small.
Sferomaki came into vogue in the 1970s, when Zharbo started working on them in the Los Alamos National Laboratory in New Mexico, but then scientists could not keep the hot plasma longer than the shortest fraction of a second. An experimental set-up the size of a car, over which Zharbo works today, is the first sferomak that holds high-pressure plasma.
“And it could go on forever, if we had the power and cooling,” – he says.
Zharbo seeks $ 8 million for the construction of a large experimental facility that can reach temperatures necessary to prove the technology works.
Which project will win, and which will receive funding is still unknown. ITER sucked most of the budget and enthusiasm; investors lost confidence in the fusion sector and are just beginning to acquire it again. If there is no money to fund some of the most promising alternative approaches, the 30-year-old dividing line between us and cheap clean energy can persist for a long time.