Two and a half years ago, MIT signed an agreement with a startup company to develop a precursor to a viable, emission-free power plant. Generally, it won’t attract too much attention – but this power plant is not solar or wind, it’s completely different: a fusion reactor.
The production of nuclear fusion has been a dream of physicists for decades, but many people did not think it was possible. Now, a total of seven papers written by 47 researchers in 12 institutions argue that not only is this possible, it is possible with today’s technology.
Simply put, reserchers see no real barrier in front of a functional fusion reactor.
Many teams are working on fusion reactors using a wide variety of technologies to produce fusion reactors. The team led by MIT is developing a “Spark” compact fusion reactor. It is essentially a “burning plasma” reactor that fuses isotopes of hydrogen to form helium without the need for any input of energy or other matter. It is one of the largest private projects in the region.
Nuclear fusion is a common process in the universe, but it is difficult to replicate on Earth. In fusion, two or more nuclear nuclei combine to form one or more different nuclear nuclei. This process releases tremendous energy – it is the one that powers the Sun and all other stars, as hydrogen atoms fuse to form helium. But stars have tremendous masses and temperatures that facilitate the process, whereas here on Earth, we need to do this in a controlled and safe manner.
If researchers can pull it off, it could one day become a safer and cleaner way of producing energy. But after more than a century of research, it is still in progress.
It is not that the field is not advanced. The first large-scale reactors (such as the giant ITER in France) are already under construction, but aside from many other challenges, large-scale reactors such as the ITER are, well, larger. This makes the construction very difficult and expensive.
Thanks to advances in the field of superconducting magnets, researchers working with SPARC are opting for a different approach: small, but efficient reactors. Spark is essentially a Tokamak – A type of imprisonment device in the shape of a torus. Superconducting magnets are important because they will be used to control extremely large temperatures and pressures inside reactors, which have consistently been one of the biggest challenges around nuclear fusion.
The SPARC has not yet housed a single brick, but in seven recently published papers, researchers make a detailed calculation of how SPARC will work. According to the team, with current technology, SPARC can produce twice the energy required to generate a reaction. This is a big deal because no other reactor has managed to break even. In fact, SPARC researchers say that the reactor can produce 10 times as much energy, but it still requires some work to be done.
“What we are trying to do is put the project on the basis of the strongest possible physics, so that we are confident of how it is going to perform, and then to guide and answer this engineering design question.” Presents, ”Greenwald said in an official statement.
If confirmed, this is a compelling approach, which could be a game-changer for the international fusion program. The authors used state-of-the-art simulations that ran on powerful supercomputers to back their case, and so far, no major obstacles have been exposed. The initial design has been slightly twisted (for example, the diameter of the tokamak has increased by 12%), but aside from minor improvements, researchers have found no reason why it should not work.
“We don’t run into anything where we say, ‘Oh, this is predicting that we won’t get to where we want to go,” notes Greenwald. In short, he says, “One of the findings is that things are still on track. We believe it’s going to work.”
“There’s always the question of a little bit more, a little bit less, and a lot of things that weigh in on it, engineering issues, mechanical stress, thermal stress, and also physics – how do you affect the performance of the device?”
The fact that the seven papers have been peer reviewed without major objection shows that the scientific world is not in opposition to the plan.
“The analysis presented in these papers will provide the world-wide fusion community with the opportunity to better understand and gauge for itself the physics base of the SPARC device, which needs to solve the remaining challenges,” George Tynan, Professor of Mechanical And aerospace engineering at the University of California at San Diego, which was not involved with the work. “Their publications mark the first demonstration of the study of burning plasmas at an important milestone on the road and the production of pure energy from controlled fusion, and I applaud the authors for seeing this work for all.”
What will happen next? Okay, actually building the thing. There are still many unknowns about the physics of plasma burning, but there seems to be enough theory to support the construction.
Since the spark is not as large and complex as other fusion reactors, construction should not take that long. “We’re still aiming for the start of construction in June of ’21,” Greenwald says.
The spark will be thoroughly tested and analyzed. If everything goes according to plan, it should be completed within the next 3-4 years, but it will not generate energy until 2035, the team notes.