Nuclear Energy Advances, to give Greenies Heartburn! By Brian Simpson
Hands up everybody here who loves nuclear, fears wind turbines, which give us bad wind, and think solar is for little more than camping expeditions? Well, here are some excellent nuclear advances. First, a high temperature superconducting electromagnet reached previously unheard of field strengths. That means that scientists are moving closer to getting fusion power to work, which will be far safer and cleaner than standard nuclear, and give almost limitless energy. And, the Chinese have made rapid advances in the development of thorium nuclear power, which is much safer than the present uranium reactors. The so-called renewable energies of the Greens, are looking more primitive by the moment!
https://phys.org/news/2021-09-superconducting-magnet-magnetic-field-strength.html?utm_source=gnaa
It was a moment three years in the making, based on intensive research and design work: On Sept. 5, for the first time, a large high-temperature superconducting electromagnet was ramped up to a field strength of 20 tesla, the most powerful magnetic field of its kind ever created on Earth. That successful demonstration helps resolve the greatest uncertainty in the quest to build the world's first fusion power plant that can produce more power than it consumes, according to the project's leaders at MIT and startup company Commonwealth Fusion Systems (CFS).
That advance paves the way, they say, for the long-sought creation of practical, inexpensive, carbon-free power plants that could make a major contribution to limiting the effects of global climate change.
"Fusion in a lot of ways is the ultimate clean energy source," says Maria Zuber, MIT's vice president for research and E. A. Griswold Professor of Geophysics. "The amount of power that is available is really game-changing." The fuel used to create fusion energy comes from water, and "the Earth is full of water—it's a nearly unlimited resource. We just have to figure out how to utilize it."
Developing the new magnet is seen as the greatest technological hurdle to making that happen; its successful operation now opens the door to demonstrating fusion in a lab on Earth, which has been pursued for decades with limited progress. With the magnet technology now successfully demonstrated, the MIT-CFS collaboration is on track to build the world's first fusion device that can create and confine a plasma that produces more energy than it consumes. That demonstration device, called SPARC, is targeted for completion in 2025.
"The challenges of making fusion happen are both technical and scientific," says Dennis Whyte, director of MIT's Plasma Science and Fusion Center, which is working with CFS to develop SPARC. But once the technology is proven, he says, "it's an inexhaustible, carbon-free source of energy that you can deploy anywhere and at any time. It's really a fundamentally new energy source."
Whyte, who is the Hitachi America Professor of Engineering, says this week's demonstration represents a major milestone, addressing the biggest questions remaining about the feasibility of the SPARC design. "It's really a watershed moment, I believe, in fusion science and technology," he says.
Fusion is the process that powers the sun: the merger of two small atoms to make a larger one, releasing prodigious amounts of energy. But the process requires temperatures far beyond what any solid material could withstand. To capture the sun's power source here on Earth, what's needed is a way of capturing and containing something that hot—100,000,000 degrees or more—by suspending it in a way that prevents it from coming into contact with anything solid.
Martin Greenwald, deputy director and senior research scientist at the PSFC, says unlike some other designs for fusion experiments, "the niche that we were filling was to use conventional plasma physics, and conventional tokamak designs and engineering, but bring to it this new magnet technology. So, we weren't requiring innovation in a half-dozen different areas. We would just innovate on the magnet, and then apply the knowledge base of what's been learned over the last decades."
That combination of scientifically established design principles and game-changing magnetic field strength is what makes it possible to achieve a plant that could be economically viable and developed on a fast track. "It's a big moment," says Bob Mumgaard, CEO of CFS. "We now have a platform that is both scientifically very well-advanced, because of the decades of research on these machines, and also commercially very interesting. What it does is allow us to build devices faster, smaller, and at less cost," he says of the successful magnet demonstration.
Proof of the concept
Bringing that new magnet concept to reality required three years of intensive work on design, establishing supply chains, and working out manufacturing methods for magnets that may eventually need to be produced by the thousands.
"We built a first-of-a-kind, superconducting magnet. It required a lot of work to create unique manufacturing processes and equipment. As a result, we are now well-prepared to ramp-up for SPARC production," says Joy Dunn, head of operations at CFS. "We started with a physics model and a CAD design, and worked through lots of development and prototypes to turn a design on paper into this actual physical magnet." That entailed building manufacturing capabilities and testing facilities, including an iterative process with multiple suppliers of the superconducting tape, to help them reach the ability to produce material that met the needed specifications—and for which CFS is now overwhelmingly the world's biggest user.
They worked with two possible magnet designs in parallel, both of which ended up meeting the design requirements, she says. "It really came down to which one would revolutionize the way that we make superconducting magnets, and which one was easier to build." The design they adopted clearly stood out in that regard, she says.
In this test, the new magnet was gradually powered up in a series of steps until reaching the goal of a 20 tesla magnetic field—the highest field strength ever for a high-temperature superconducting fusion magnet. The magnet is composed of 16 plates stacked together, each one of which by itself would be the most powerful high-temperature superconducting magnet in the world.
China is poised to test a thorium-powered nuclear reactor in September, the world’s first since 1969. The theory is that this new molten-salt technology will be “safer” and “greener” than regular uranium reactors, and so could help Beijing meet its climate goals. Yet is the country's investment in this also geostrategic?
A new page in the history of nuclear energy could be written this September, in the middle of the Gobi Desert, in the north of China. At the end of August, Beijing announced that it had completed the construction of its first thorium-fuelled molten-salt nuclear reactor, with plans to begin the first tests of this alternative technology to current nuclear reactors within the next two weeks.
Built not far from the northern city of Wuwei, the low-powered prototype can as yet only produce energy for around 1,000 homes, according to the scientific journal Nature.
But if the upcoming tests succeed, Chinese authorities will start a programme to build another reactor capable of generating electricity for over 100,000 homes. Beijing could then become an exporter of a reactor technology that has been the subject of much discussion for over 40 years, according to French financial newspaper Les Echos.
Lower accident risks?
The Chinese reactor could be the first molten-salt reactor operating in the world since 1969, when the US abandoned its Oak Ridge National Laboratory facility in Tennessee.
“Almost all current reactors use uranium as fuel and water, instead of molten salt and thorium," which will be used in China’s new plant, Jean-Claude Garnier, head of France’s Alternative Energies and Atomic Energy Commission (CEA), told FRANCE 24.
These two "new" ingredients were not chosen by accident by Beijing: molten-salt reactors are among the most promising technologies for power plants, according to the Generation IV forum – a US initiative to push for international cooperation on civil nuclear power.
With molten-salt technology, "it is the salt itself that becomes the fuel", Sylvain David, research director at the French National Centre for Scientific Research (CNRS) and nuclear reactors specialist, explained in a FRANCE 24 interview. The crystals are mixed with nuclear material – either uranium or thorium – heated to over 500°C to become liquid, and are then be able to transport the heat and energy produced.
Theoretically, this process would make the installations safer. "Some accident risks are supposedly eliminated because liquid burning avoids situations where the nuclear reaction can get out of control and damage the reactor structures," Jean-Claude Garnier added.
There's another advantage for China: this type of reactor does not need to be built near watercourses, since the molten salts themselves "serve as a coolant, unlike conventional uranium power plants that need huge amounts of water to cool their reactors", French newspaper Les Echos noted. As a result, the reactors can be installed in isolated and arid regions… like the Gobi Desert.
China's plentiful supply
Beijing has also opted to use thorium rather than uranium in its new molten-salt reactor, a combination that has drawn attention from experts for years. This is mostly because “there is much more thorium than uranium in nature”, Francesco D’Auria, nuclear reactor technology specialist at the University of Pisa, told FRANCE 24.
In addition, thorium belongs to a famous family of rare-earth metals that are much more abundant in China than elsewhere; this is the icing on the cake for Chinese authorities, who could increase its energy independence from major uranium exporting countries, such as Canada and Australia, two countries whose diplomatic relations with China have collapsed in recent years.
Beijing’s investment is also a long-term one. “For now, there is enough uranium to fuel all operating reactors. But if the number of reactors increases, we could reach a situation where supply would no longer keep up, and using thorium can drastically reduce the need for uranium. That makes it a potentially more sustainable option," Sylvain David explained.
A 'greener' nuclear energy?
According to supporters of thorium, it would also a "greener" solution. Unlike the uranium currently used in nuclear power plants, burning thorium does not create plutonium, a highly toxic chemical element, Nature pointed out.
With so many positives on their side, why are molten salts and thorium only being used now? “Essentially because uranium 235 was the natural candidate for nuclear reactors and the market did not look much further," Francesco D'Auria added.
Radiation, corrosion and... nuclear weapons
Among the three main candidates for nuclear reaction – uranium 235, uranium 238 and thorium – the first is “the only isotope naturally fissile”, Sylvain David explained. The other two must be bombarded with neutrons for the material to become fissile (able to undergo nuclear fission) and be used by a reactor: a possible but more complex process.
Once that is done on thorium, it produces uranium 233, the fissile material needed for nuclear power generation. That then becomes another problem with thorium: "The radiation emitted by uranium 233 is stronger than that of the other isotopes,
The feasibility of molten-salt reactors is also questionable as it creates further technical problems. "At very high temperatures, the salt can corrode the reactor’s structures, which need to be protected in some manner," Jean-Claude Garnier explained.
The stakes are clearly high for the Chinese tests and they will be watched very closely around the world in order to see how Beijing hopes to overcome these obstacles. But even if China ends up claiming victory, they should not rejoice too quickly, Francesco D’Auria said: "The problem with corrosive products is that you don't realise their damage until five to 10 years after."
Moreover, the expert claims there is no reason to celebrate a nuclear reactor that not only produces energy, but also uranium 233. "This is an isotope that does not exist in nature and that can be used to build an atomic bomb," pointed out Francesco D'Auria.
As such, China could end up revolutionising the nuclear industry but, at the same time, they might once more alarm supporters of non-proliferation around the world.”
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