KeysQuestions4Explore4<\/p>\n
Demo4 just ran 44 superconducting coils at 13.7 tesla for 14 months straight, and that endurance record matters far more than the peak field number ever could.<\/p>\n
The coils survived sideways mechanical stresses equivalent to nearly 1,500 times atmospheric pressure \u2014 and the material doing it is called “high-temperature” superconducting tape while operating at 429 degrees below zero Fahrenheit, which tells you something is off about that name.<\/p>\n
If fusion power ever shows up on your electricity bill, the economics behind it will trace directly back to whether magnets like these can run like appliances instead of laboratory experiments \u2014 and Demo4 was built specifically to answer that question.<\/p>\n
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<\/p>\n Energy<\/p>\n A wind turbine built to stand 1,198 feet tall in eastern Germany can\u2019t even get its three blades bolted on in strong wind, and once they\u2019re on, hydraulic jacks still have to push its 827-ton top up through the lattice tower at 30 feet an hour to a hub height of 984 feet<\/p>\n 2 hours<\/p>\n <\/a><\/p>\n Energy<\/p>\n A 935-foot wind turbine in Bavaria carries its hub 653 feet up, the tallest on land, on a concrete-and-steel tower its maker builds more than 1,000 times a year, and the company stood it in its own yard to cover two-thirds of the factory\u2019s power<\/p>\n 21 hours<\/p>\n <\/a><\/p>\n Energy<\/p>\n A safety battery cell at a Michigan nuclear plant died the way a car battery dies in a winter parking lot, one lump of paste inside shorted it to the plate next door, and the flaw had sat quiet inside the sealed box for more than ten years before a test caught it<\/p>\n 23 hours<\/p>\n <\/a><\/p>\n Energy<\/p>\n A 12-foot bundle of 216 fuel rods tilted over inside the first American reactor being pulled back from decommissioning, after the loading machine had set it in the core and let go, and engineers are now designing tools just to lift that one bundle back out<\/p>\n 1 day<\/p>\n <\/a>AI-generated summary from reviews, comparisons and articles by AutoNotion<\/p>\n If you\u2019ve ever had an MRI, you\u2019ve been inside the strongest magnet most people will ever get near. Those machines run at about 1.5 to 3 tesla, and hospitals respect them enough to screen every paperclip that enters the room. So when a fusion company outside Oxford, England, says its magnet system peaked at 13.7 tesla and held together, that number\u2019s earned a second of your attention.<\/p>\n The company is Tokamak Energy, and the system is called Demo4: 44 superconducting coils arranged the way they\u2019d wrap around a spherical tokamak<\/a>, the squashed version of the classic donut-shaped fusion reactor, plus the cooling, power and control gear needed to run them as one machine. Tokamak Energy announced on September 9<\/a> that it had finished a 14-month test campaign on the whole assembly. And honestly, the 13.7 tesla wasn\u2019t the number that got me. Demo4 spent roughly 10,000 hours energized over those 14 months, by the company\u2019s count, including long stretches at high field.<\/p>\n Why do the hours impress me more than the teslas?<\/p>\n Because holding a big field for a moment is a lab trick you can pull off with one heroic coil. Holding field for months on end, across 44 coils that all push and pull on each other, while the cryogenic plant, the power supplies and more than 600 sensors behave themselves, is a lot closer to what a power plant\u2019s going to need from its magnets. Reactors don\u2019t get sick days.<\/p>\n A quick refresher on why fusion needs any of this: the reaction only happens once hydrogen fuel gets heated into a plasma several times hotter than the sun\u2019s core, and nothing solid can touch something that hot. So magnetic fields do the holding, and the stronger the field, the smaller and cheaper the reactor around it can be.<\/p>\n For scale, I ran the arithmetic on 13.7 tesla, and it works out to roughly 270,000 times the magnetic field you\u2019re standing in right now, give or take, depending on where on the planet you do your standing. The forces at that strength are vicious. Tokamak Energy says the coils rode out transverse mechanical stresses of about 21,750 psi (150 MPa), the field trying to shove the conductors sideways out of their own supports, and Nuclear Engineering International<\/a> puts that load at almost 1,500 times atmospheric pressure.<\/p>\n So what\u2019s a \u201chigh-temperature\u201d superconductor doing at 429 below?<\/p>\n Demo4\u2019s coils are wound from high-temperature superconducting tape, HTS if you want the industry shorthand, and the name\u2019s a bit of a bait and switch. A superconductor is a material that carries electric current with zero resistance once you get it cold enough, and that\u2019s what lets a magnet this strong run without cooking itself. Demo4\u2019s \u201chigh-temperature\u201d coils still operated between 321 and 429 degrees below zero Fahrenheit (77 down to 17 Kelvin) during the campaign. That only counts as warm because the older superconducting wire in an MRI machine has to sit near 452 below to work at all. Every degree you skip chilling saves real money in a power plant, and that\u2019s basically why the industry keeps betting on HTS.<\/p>\n The cooling ran on pressurized helium at up to 290 psi (20 bar), and the team deliberately cycled the system around that temperature range instead of parking it at one comfortable setting. The toroidal field coils also carried 5,600 amps, against the 200-amp rating of the main panel in a typical American house.<\/p>\n Autonoci\u00f3n Newsletter<\/p>\n No spam. Unsubscribe anytime. Privacy policy (opens in new window)<\/a><\/p>\n Then there\u2019s the abuse. A superconducting magnet stores a serious amount of energy, and if part of a coil suddenly stops superconducting, all of that energy has to go somewhere in a hurry. So the engineers triggered forced discharges on purpose, several of them, at fields up to 12.5 tesla, essentially pulling the fire alarm to make sure the building actually empties. Frankly, that\u2019s the data I\u2019d want most if I were designing a power plant around these magnets, because a magnet that can\u2019t survive its own faults is just a very expensive liability with a cryostat around it.<\/p>\n \u201cDemo4 proves our integrated magnet system can perform under demanding fusion-relevant configurations,\u201d said Liam Brennan, who runs TE Magnetics, the company\u2019s magnet division.<\/p>\n Peak field<\/p>\n 13.7 T<\/p>\n Roughly 270,000 times the Earth\u2019s magnetic field.<\/p>\n Time energized<\/p>\n ~10,000 hrs<\/p>\n Hours under power across the 14-month campaign.<\/p>\n Coil count<\/p>\n 44<\/p>\n 14 toroidal limbs of two HTS coils, plus two poloidal stacks of eight.<\/p>\n Coldest point<\/p>\n \u2212429\u00b0F<\/p>\n 17 Kelvin, cooled by helium pressurized to 290 psi.<\/p>\n Not everyone builds fusion magnets the same way<\/p>\n Demo4\u2019s previous public milestone was 11.8 tesla, so the field moved a fair distance over the course of the campaign. And Tokamak Energy isn\u2019t the only outfit treating the magnet, rather than the reactor, as the product. Thea Energy, a Princeton spinout working out of New Jersey, went the opposite direction with stacks of identical flat coils for a stellarator, and its test magnet reached 6 tesla<\/a>, which we covered earlier this month. Two very different bets on the same physics, and as far as I can tell, nobody in the industry agrees yet on which magnet architecture ends up in the first commercial plant.<\/p>\n There\u2019s a destination for the Demo4 data, too. Tokamak Energy is the magnet systems partner for STEP, the UK government\u2019s prototype fusion power plant, and it\u2019s feeding the results into that design work with UK Fusion Energy, the state-owned body delivering the project. STEP is planned for West Burton<\/a>, a former coal power station site in Nottinghamshire, and that\u2019s arguably the tidiest piece of site symbolism this industry has managed so far: superconducting magnets moving onto ground where a coal plant spent decades burning through trainloads of the stuff.<\/p>\n What comes after Demo4 isn\u2019t as clear. The announcement mentions better ways of making and joining the coils, upgraded instrumentation and a firmer grip on operating margins, but I couldn\u2019t find a named successor system in it, or a date for building the STEP magnets themselves. I wouldn\u2019t read too much into that silence. ITER<\/a>, the 35-nation reactor going up in southern France, is still qualifying the tooling that\u2019ll merely assemble it, and fusion hardware generally moves at fusion speed.<\/p>\n Tokamak Energy closed the campaign out with its September 9 announcement, and STEP\u2019s targeting first operations at West Burton in 2040. That gives everyone involved about 14 years, and from the looks of things, the magnet people don\u2019t plan on being the bottleneck.<\/p>\n","protected":false},"excerpt":{"rendered":"KeysQuestions4Explore4 Demo4 just ran 44 superconducting coils at 13.7 tesla for 14 months straight, and that endurance record…\n","protected":false},"author":2,"featured_media":904219,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[64,63,292,128],"class_list":["post-904218","post","type-post","status-publish","format-standard","has-post-thumbnail","category-physics","tag-au","tag-australia","tag-physics","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/904218","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=904218"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/904218\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/904219"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=904218"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=904218"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=904218"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}