Did you hear the news? Argentina is going to the World Cup finals!? Yes, but not that. Fusion had its first positive energy yield!
Behind the reactors and beyond the news headlines, it is indeed a big deal, big news, a bigger deal for humanity than all the world cups combined. It should be at least. This is Nobel Prize stuff. And much more.
Humans reproduced a tiny part of the sun almost exactly 70 years ago when we managed the first man-made fusion reaction, the joining of two atoms into one creating one of lesser mass than the sum of its parts and converting the lost mass into massive energy (e=mc2), the Hydrogen Bomb.
But the energy it took to create the first man-made atomic fusion reaction was so large that it took an initial fission reaction (the atomic bomb) to fuel the fusion. It took a lot more energy to fuel the explosion than the explosion itself yielded.
On Tuesday, the Lawrence Livermore National Laboratory’s (LLNL’s) National Ignition Facility (NIF) in California announced that for the first time, we have been able to create a reaction that yielded more energy than it took to fuel the reaction. This is called fusion-ignition. It was accomplished in the laboratory. No such feat has been ever done before.
Imagine if every time you ran your car, you parked with more fuel than you had when you began. That is the world of possibilities that this means. To be exact, this example would be only applicable to breeder designs; laser inertial confinement may not be compatible. And, of course, for it to work, there must be constant mass but more fuel, as matter cannot be created.
The announcement is a big deal for all fusion, however, this positive energy release only considers the immediate energy put into the reaction and not the energy needed to run other vital components of the facility. This means that the value of positive energy release will have to increase to cover the totality of the energies needed to operate the entire facility, thus economic viability has to clear that first hurdle and more.
Research being done at facilities like the biggest fusion reactor in existence at the International Nuclear Energy Research program, ITER is also on the path to claiming positive energy (+Q) release but only with respect to immediate energy put into the reaction, thus not making it economically viable either until the value of Q can increase.
It is "a road ahead to the possibilities for clean energy," said Arati Prabhakar, the White House science adviser, at a news conference on the announcement Tuesday at the Department of Energy’s headquarters in Washington, D.C.
Fusion is touted as a paragon of clean energy since it does not create radioactive waste that lasts hundreds of years, the drawback of the current generation of uranium-splitting nuclear power plants.
While the uranium fuel used today is radioactive itself, the fuel for fusion is ocean water and elements like lithium, specifically Li-3, that can absorb a neutron into helium and decay into tritium. Lithium too is abundant; thus, we may see future fusion reactors using liquid lithium pumped around the periphery of the core, exposing it to neutrons, and transmuting it into more fuel. Translation, while fission reactors utilize highly radioactive fuel and produce long-lasting nuclear waste, fusion uses neither radioactive fuel nor yields such waste. That is why fusion is the holy grail of energy production, further, it does not burn fossil fuels that cause greenhouse gases and global warming.
But now science needs to answer questions like how to extract energy productively from this apparatus. It cannot be used to make steam-like fission reactors, nor can it be hooked up to a thermocouple to control the reactions since it is being bombarded with lasers from all sides.
Fission is a self-sustaining chain reaction, which makes it incredibly efficient. The question at hand today is, can man eventually make fusion self-sustaining like in the sun and the stars?
There is a lot of consideration, beginning with a misconception that a single fusion reaction yields more energy than a single fission reaction. This is false, considering the implicit caveat of the per-unit mass of fuel. Hydrogen has an atomic mass of 1, while Uranium, the fuel for fission reactions, has a mass of around 238. Thus, science has to be able to produce a lot more fusion reactions to make its energy release competitive with fission.
Let us delve into this further.
There are different types of hydrogen, and they can be mixed to produce fusion.
Hydrogen comes in 3 flavours or isotopes. What we commonly refer to as hydrogen is merely an atom with one proton in its nucleus. When a neutron is added, it becomes deuterium, the hydrogen that makes heavy water. With two neutrons, it becomes tritium, for its atomic weight of 3. Hydrogen used in fusion has an atomic mass between ~2-3 atomic mass units – deuterium or tritium.
Hydrogen fusion can take the form of 2 deuterium atoms (D-D) or deuterium and tritium (D-T), which yields more energy, simply because more mass is involved, e=mc2 again. Unfortunately, tritium has a half-life of 10 years and does not occur naturally.
Science has created this fusion before, but this time the results were something extraordinary.
It happened at 1:03 a.m. on Dec. 5 and lasted under 100-trillionths of a second, when 192 giant lasers at NIF vaporized a pellet of frozen hydrogen encased in diamond; the resulting X-rays acted on deuterium and tritium fuel causing fusion that carried a brief-but-historically significant release of energy because, for the first time in history, a manmade fusion experiment showed an energy gain on a factor of 1.5.
That was the moment of fusion ignition, the moment science crossed the threshold where the output of energy equalled the input of energy needed to start the reaction. This was achieved with laser inertial confinement, though it took the world’s most powerful laser, and a $3.5 billion facility the size of a World Cup stadium, an indication of the high thresholds required to achieve this important but very early step on the road to economic viability.
The moment is historic and of note, however, because it was fusion’s Wright Brothers moment - the short flight by man that led humanity to explore the moon and the heavens to have 100,000 flights crossing the Earth’s skies every day, a beginning that promises to lead man to Mars someday. So, will this change our world?
