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Nuclear fusion: it's time for a reality check
- einpoklum 2y agotl;dr: A British politician suggested we are "within grasping distance" of using fusion for wide-scale power generation; the letter published in the Guardian explains how significant challenges remain both with the core process and surrounding considerations. (i.e. letter explains why we are "30 years away" at least, not 3 years away)
- gerikson 2y agoNuclear fusion has been 3 decades away since as far as I can remember (I believe I first read about it in National Geographic in the late 70s or early 80s)
- flohofwoe 2y agoI seem to remember that in socialist Eastern Europe it was only always 15 years away ;)
- ChocolateGod 2y agothen in Deepseek like fashion China comes along and does it for 1/10th the cost and time. In the same time the UK has been arguing over a third runway at its biggest airport, China has built over 100 new airports (20 years).
- danparsonson 2y agoChina also has an order of magnitude more land available, and a fascist government. Arguing over squeezing a new runway into a built-up area is a good thing.
- einpoklum 2y agoYou will note I said "at least" rather than "at most" or "about" ;-) ... we're all familiar with the phrase I believe
- Red_Comet_88 2y agoAll well and good, but Commonwealth Fusion and Tokamak Energy are building large test reactors are we speak in hopes of answering these exact questions. These aren't science projects, but tech demonstrators designed as a stepping stone to commercial fusion. The points raised in the article are valid, but can only be tested by building reactors, which is currently happening in the above companies.
- teamonkey 2y agoAgreed, but the problem isn't about funding fusion research - which isn't a bad thing IMO - more that the UK government seem to believe that it's "coming soon". The concern is that they're basing future energy policy on a technology that may not be a practical power source for generations (or ever). See also their recent commitment to using AI. Funding AI research and supporting AI startups: sure. Basing policy on the fact that AI can replace civil servants and other workers: there should probably be some evidence of that first.
- shellac 2y agoWorth noting that the author of this letter works at Culham Centre for Fusion Energy, where JET is located. 'Abingdon' was a clue but they could have filled in the detail.
- raverbashing 2y agoYeah I agree The hard part here is twofold: there are several orders of magnitude needed to be overcome (in efficiency) for it to work. Also the learning curve in fusion is not a curve, but more like a staircase with very tall steps ITER is gearing up to be a great disappointment I really don't feel like magnetic confinement is the way to go, unless we get some new superconducting technology and need to create electromagnets with 100x their current strength
- amelius 2y ago> unless we get some new semiconductor technology Did you mean superconductor technology?
- raverbashing 2y agoYes, fixed
- oneshtein 2y agoWe see already, that Tokamak's will be very expensive to build and operate.
- DennisP 2y agoWe actually do have commercially available superconductors that support much stronger magnetic fields than what ITER is able to do. I don't think it's 100x, but it doesn't have to be. Tokamak output scales with the fourth power of magnetic field strength. Double the field, 16X the energy output. CFS and Tokamak Energy are building tokamaks with these. Tokamak output also scales with the square of reactor size, which is why ITER is so big. These new reactors can be much smaller for the same output, so they'll be much faster and cheaper to build. The CFS design is about the size of JET, which was built in four years, with three of those being just for the building.
- UltraSane 2y agoWhy doesn't ITER use the better superconductors?
- GTP 2y agoThere are a few things I don't get of the fifth point: why do we need to be able to operate nuclear fusion plants remotely? Wouldn't it be not just possible, but maybe even preferable, to have staff on site to manage the plant, like it is the case for fission plants? And if we still want remote control, why is this such a big challenge? With a background in computer engineering and cybersecurity, this seems to me the smallest challenge of the list.
- aqme28 2y agoI think they mean that we shouldn't have to send a guy inside the reactor to clean and reset it up every time you fire it. I don't really know why they listed this point.
- GTP 2y agoSeeing it from this perspective, maybe I now see it: the residual radioactivity inside the reactor may be strong enough to mess with the electronics of a robot you're sending inside. Maybe there are challenges in getting enough shielding while keeping the robot reasonably sized and maneuverable.
- grues-dinner 2y agoA major challenge is getting the robot into the place you need it, along with other objects it needs like replacement parts, in between the other infrastructure like coils and cooling blankets. You mustn't damage the delicate reactor structures, you can't have rails and so on always in the reactor vessel, the vessel has to be vacuum tight, and most of all you must not allow the robot to fail and be unextractable, because humans can't go in an pull it out. ITER seems to have a project called the Agile Robot Transporter which you can see some renders of that demonstrate how fiddly this problem is.
- pbronez 2y agoThis presentation has some useful illustrations about the ART: https://indico.iter.org/event/45/contributions/1090/attachments/492/776/S4_Hery_The_Agile_Robot_Transporter_for_ITER_Diagnostic_Calibration-20221004.pdf https://indico.iter.org/event/45/contributions/1090/attachme...
- ZhiqiangWang 2y agoThen there might be a “DeepSeek” moment.
- GTP 2y agoYes, but just throwing in the possibility of a future unexpected breakthrough without grouding this in the situation so far, can lead to wishful thinking. The fact that the list has 5 independent points means that you need 5 independent breakthroughs, making it even less likely to happen in the short term.
- _heimdall 2y agoFor a DeepSeek moment, the west would first have to produce a functional, but Wildly expensive fusion reactor. Then someone else could ask the reactor questions over and over until they understand well enough how the reactor works.
- grues-dinner 2y agoThe DeepSeek moment for nuclear power might be accelerator-driven subcritical reactors that make fission plants much simpler and safer (and therefore cheaper, the key element of DeepSeek moment) by never having a critical mass of fuel in the reactor - criticality is only possible when a particle accelerator is illuminating the core, and the accelerator can just be turned off.
- tim333 2y agoHelion are saying they may have commercial energy shortly although no one really believes them.
- pfdietz 2y agoSome people make bizarre claims they're a scam, but (in addition to being libelous) that's as unsupportable as claiming now they will succeed. My position is they're the least dubious of all the fusion efforts, and have a very clever design that offers the plausible possibility of avoiding some of the engineering and economic showstoppers confronting DT fusion. Of course no pudding can be eaten before it's cooked, and no reactor design can be counted on before it's proved.
- aqme28 2y agoThey listed 5 challenges but they forgot probably the biggest one-- Make it cheaper than the alternatives. That might never happen even if we do solve all the material and technical problems. Disclaimer-- I did my masters on fusion reactor simulations.
- acidburnNSA 2y agoFully agreed. It took us from 1944 to 1965 in fission to go from "ok it makes net energy" to "ok we can make electricity on the commercial market within the realm of the existing alternatives". Fusion is still pre-1944 in that they haven't even demonstrated getting net energy out, let alone put together an electricity-generating machine. I have no doubt at all that we'll make fusion-derived electricity in my lifetime. But I have no idea whether or not we'll make it cheap. They say the fuel is cheap. It's not (tritium and He-3 are hard to come by), but even if it were, keep in mind that a fleet of uranium-fueled fission reactors like the one in France spends about 5-10% of its costs on fuel.
- ajross 2y ago"Within the realm" involves some externalities though. Fission reactors have never been particularly cost competitive with other electrical generation technologies. They were subsidized heavily because people wanted reactors to build bombs, and more broadly to cultivate a technology base of people who could build and maintain reactors to build bombs. Once we had enough bombs, that subsidy got rolled back and fission fell off the leaderboard.
- acidburnNSA 2y agoIf you spend as much time reading the early 1950s documentation of the nuclear industry, you'll quickly see that commercial nuclear reactor development was very much decoupled from the graphite or heavy-water moderated bomb-making reactors. They separated around 1953 and never came back together. Back then, the fledgling industry was wondering if they could sell excess plutonium for bombs, but the government said that they were not interested in buying it. They said they had more than enough coming from their own specialized bomb-making reactors. Certainly nuclear tech was subsidized originally by the Manhattan project, but very soon after, bomb making and nuclear power went their separate ways. You could much more strongly argue that the nuclear reactor development made to power submarines helped develop the commercial nuclear power industry. This checks out much more cleanly, as Shippingport was led by Rickover himself.
- moonlion_eth 2y ago[flagged]
- librasteve 2y agopolitician == lying idiot (esp Ed Miliband)
- M95D 2y agoSo, some scientists lied to a politician? Considering how much politicians lie, I think what they did is normal and almost OK.
- Etheryte 2y agoI don't see any scientists lying mentioned in the article, where did you get that takeaway? We see policymakers ignore competent advice on all fronts all the time, I wouldn't be surprised if that's the case here too.
- M95D 2y agoI probably read wrong.
- kragen 2y agoEd Miliband, the liar quoted in the letter, is a politician and not a scientist. The author of the letter, a scientist, is telling the truth.
- jmyeet 2y agoI agree with all this. People make two big mistakes when evaluating fusion: 1. The fuel is free to cheap, depending on the fuel; and 2. Stars can do it so surely we can. So let's consider a mythical plant that costs $30B to build, has a lifetime of 30 years, costs $3B/year in maintenance and produces 1000MW of power. And the fuel. is free. Is the electricty free? Not even close. That's ~8.8GWh per year. No plant runs at full capacity 24x7 so let's call it 4TWh. That's about $1/kWh. That's ludicrously uneconomical. Of course you can throw in vastly different numbers and vastly different results but the main point is that fuel cost is a non-issue. And as the article points out, in a D-T reactor, you still need to produce tritium because it's basically not naturally occurring in a way that can be gathered. That means a fission breeder reactor. That fuel isn't free. Second, "the Sun does it" misses the point. As the article correctly points out, damage from neutrons ("neutron embrittlement") is a huge problem. Beyond that, it's a huge problem because every high-speed electron that escapes the plasma is energy loss from the system. Stars use gravity for containment.
- jcarrano 2y agoAlso, the power density of the sun is extremely low. A rotting orange produces more power per unit mass.
- pfdietz 2y ago> And as the article points out, in a D-T reactor, you still need to produce tritium because it's basically not naturally occurring in a way that can be gathered. That means a fission breeder reactor. That fuel isn't free. It doesn't require a fission breeder reactor. All DT schemes imagine a blanket where they breed their own tritium, and produce enough to start additional DT reactors. Some imagine a startup phase where they run just on DD for a few months, with Q < 1, to make enough tritium to start up. If fission had to be used to make all the T then DT fusion would be a complete nonstarter economically.
- arghandugh 2y agoThere’s good old #4 again: fusion processes inevitably create extreme neutron fluxes capable of turning everything they touch into radioactive waste. Meaning the reactor vessel and all involved fluids and support structures for handling thereof. Congrats! All the hassle of fission with more steps. Proceed to scream at me!
- pmontra 2y agoThere is also fusion with low neutron flux [1] (among the others: Helium 3) but it is even more difficult to achieve. I'm not confident that any of us will ever see a commercial fusion reactor. I'm afraid that all we can do to harness fusion energy directly is by the means of solar panels. [1] https://en.wikipedia.org/wiki/Aneutronic_fusion https://en.wikipedia.org/wiki/Aneutronic_fusion
- mystified5016 2y agoRadioactive waste isn't an intractable problem. It is simply a problem we refuse to deal with.
- foxyv 2y agoYeah, that's something I've been wondering about for a while. Sure you can get Fusion to create energy eventually, but the engineering to keep the reactor running long enough to break even on cash sounds even more difficult. Anything involving hot plasma and large amounts of ionizing radiation is going to play hell with your equipment. That's not even considering the secondary nuclear waste created by the neutron, proton, and alpha radiation. It just seems like a great way to turn a billion dollars into a pile of extremely hot, radioactive, radiation embrittled metal.
- arghandugh 2y agoCorrect. But that’s not what was promised in the brochure, hence the gnashing of teeth and the wailing in sackcloth every time anyone sits down and tries to reason out what Free Limitless Fusion Power would actually look like as an actual industry on actual Earth.
- mppm 2y agoAlso relevant: The Trouble With Fusion [1]. It's from 1983, but could well have been written today, as nothing has really changed in the grand scheme of things. In short, there are multiple technical and economical challenges that stand in the way of nuclear fusion becoming a viable path towards clean energy, even after the first successful demonstration of a self-sustained burning plasma. Which, by the way, still seems about 10 years out, with the latest round of delays on ITER. I think most of the people involved understand this, but there is ongoing political will to sink billions of dollars into these projects, so here we are. 1. https://orcutt.net/weblog/wp-content/uploads/2015/08/The-Trouble-With-Fusion_MIT_Tech_Review_1983.pdf https://orcutt.net/weblog/wp-content/uploads/2015/08/The-Tro...
- pfdietz 2y agoLidsky is long dead (as are Pfirsch and Schmitter, who had similar critiques in Germany), but I like to think he'd have been a supporter of Helion. Helion's approach is close to what Lidsky advocated (aneutronic fusion), at least before Lidsky's student Todd Rider showed truly aneutronic fusion was not likely to work. However, the Helion approach has greatly reduced neutronicity, particularly of energetic DT neutrons, and exploits the kind of non-Maxwellian plasmas w. energy recovery/recirculation that Rider was analyzing.
- spintin 2y ago[dead]
- UltraSane 2y agoAll money being spent on fusion research would be much better spent building the most modern and safe fission reactor designs.
- stronglikedan 2y agothere's plenty of money for both. fusion is too important to eschew
- UltraSane 2y agonot if climate change is as bad as it could be. Fission reactors can actually reduce CO2 emissions. Fusion reactors not so much.
- driver49 2y agoI find all this discussion... well... amusing. There may be a reasons we don't have fusion energy that have nothing to do with the physics or engineering. What if I told you "fusion is not (perpetually) 20 years in the future... it's 60 years in the past and we missed it." ? There's a story here, but it requires a bit of suspension of orthodox belief: https://waterstarproject.com/read-the-waterstar-manifesto/ https://waterstarproject.com/read-the-waterstar-manifesto/ https://waterstarfoundation.org https://waterstarfoundation.org -- Paul Schatzkin (actual name!)
- Gud 2y agoMeanwhile, in Massachusetts... https://news.mit.edu/2024/commonwealth-fusion-systems-unveils-worlds-first-fusion-power-plant-1217 https://news.mit.edu/2024/commonwealth-fusion-systems-unveil...
- maxglute 2y agoWhat happens if fusion reactor meets a bomb?
- driver49 2y agoWhat kind of bomb are we talking about here? Conventional chemical explosives? Atomic (fission) bomb? Hydrogen (fusion) bomb? The fusion reactor would just fizzle out the moment the vacuum is breached. Not sure I can say the same for the bomb. --PS
- maxglute 2y agoConventional. So sounds like not much?