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The quest for fusion energy
- notorandit 4y agoFear the e-cat scam!
- ThrowawayTestr 4y agoCheck out General Fusion for a company that's working on an actually tenable fusion reactor.
- ncmncm 4y agoAnd even that wouldn't be competitive with existing wind and solar tech.
- pfdietz 4y agoIt requires considerable optimism to think GF's approach is "tenable". I don't believe it is.
- ThrowawayTestr 4y agoThey're currently building a test reactor in the UK. We'll see in a couple years.
- kkfx 4y agoCurious that they do not mention the far more developed fusion reactor in France, but anyway while I prize research in general I always reiterate that we can and MUST dream, but at a society scale, not company, not lab, we need thing that work for sure NOW. Witch means that's hyper-right funding a PUBLIC research on fusion energy even if it demand *centuries* before showing usable results, BUT we have an energy production issue now and we need to sort it out quickly for real, not in a potential future...
- moogly 4y agoITER was mentioned several times in the article. I am guessing that's what you meant by "far more developed fusion reactor in France", even though "far more developed" could be argued since it's still under heavy construction and has not started operation, and thus has produced no results as of yet. D-T operations are scheduled for 2035, and it will most certainly miss that target. Plus, it's still an experimental reactor and meant to be a proof of concept. DEMO, a commercial reactor, would then be designed and constructed using the learnings of ITER (if it turns out feasible, which is unproven at this point).
- ceeplusplus 4y agoMoonshots need a focused direction of R&D, not design by committee. ITER is the definition of design by committee. VC backed funding is a much better model for this kind of idea where the tech is _almost_ there but need capital intensive build outs to validate it.
- Bouncingsoul1 4y agoReally? the actual moonshot was exactly this, design by committee, no VC backed funding...
- pfdietz 4y agoApollo was also a dead end. It resulted in a system that was so expensive not even the government wanted to keep using it. It's taken a private approach to get launch costs down to the point that returning the moon may be practical.
- BuyMyBitcoins 4y agoIf we had stuck with the Saturn V and conducted one moon landing per year, it would have been far cheaper than the Space Shuttle program. I applaud the private sector’s results, but the Apollo program was a national triumph and should in no way be considered a dead end technologically. It was the politicians that failed the program, not the other way around.
- idatum 4y ago"The incoming fusion neutrons sustain the temperature of the circulating liquid metal, whose heat would be extracted to drive a turbine." I assume this means a steam turbine (heat engine). With the losses inherent in that process, I assume the idea is we'll have a "limitless" source of heat anyway? Or is heat transfer inherently better with this fusion design?
- gameswithgo 4y agoWhat other process do you propose? A steam turbine is the best way we know how.
- bryanlarsen 4y agoIf fusion relies on a steam turbine, it's going to be economically infeasible. Natural gas power is cheaper than either coal and fission power because they both rely on big, heavy, expensive, inefficient steam turbines. And solar power and wind is cheaper than natural gas, even with batteries.
- perihelions 4y ago- "Natural gas power is cheaper than either coal and fission power because they both rely on big, heavy, expensive, inefficient steam turbines." Most natural gas power plants in the USA use steam turbines. The most common setup is a two-stage "combined cycle": first, an internal-combustion gas turbine, whose waste heat powers a lower temperature steam turbine. https://en.wikipedia.org/wiki/Combined_cycle_power_plant https://en.wikipedia.org/wiki/Combined_cycle_power_plant https://www.eia.gov/todayinenergy/detail.php?id=39012 https://www.eia.gov/todayinenergy/detail.php?id=39012 (~90% of natural gas kWh)
- bryanlarsen 4y agoThe gas turbine is primary in combined cycle. There's a reason they don't use only a steam turbine like coal and fission do.
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- jonplackett 4y agoIt’s amazing just how many problems scaled up fusion would solve. War in iraq? Why bother. War in Ukraine? Just stop giving Russia fossil fuel money Climate change? Let’s just not. Why aren’t we just spending _all_ the money on this?
- rapsey 4y agoBecause it is still very much up in the air if fusion is cost effective. If the price to build a plant is astronomical it can not make enough energy to pay for itself. A better question is why we are not investing in solar, wind and hydrogen more.
- grej 4y agoThose have a role in the energy landscape to be sure, but they don’t offer the benefits of fusion because they don’t have the same power density.
- ncmncm 4y agoFusion does not "offer benefits" of any energetic or economic kind. It is interesting in the same ways that microkelvin cryogenic and gigapascal hyperpressure are, exercising extreme physics. Fusion does not offer energy density even approaching commercial fission.
- deepspace 4y agoYes, but they have the incredible advantage that they produce large amounts of energy economically today, whereas, as the article states, it is not yet clear whether fusion will ever be able to produce significant energy, let alone economically.
- p1mrx 4y agoWind and solar only produce energy when the weather is cooperating, and it's difficult to predict how climate change will impact future availability. Hydrogen might be economical someday, but currently it's rather difficult to generate, store, and transport.
- DennisP 4y ago> there are daunting engineering challenges involved in stabilizing a torus where the inboard legs of the magnet coils are subjected to extraordinarily high electromechanical stresses and overturning moments. True, but MIT (and by extension CFS) has more experience with this than anyone. Their Alcator C-Mod had the strongest magnetic field of any tokamak. I got a tour of it once, and a grad student showed us a metal tie rod, about a meter long. He said they'd calculated that two of them could have held down the Space Shuttle when it was trying to launch. To keep the reactor from flying apart, they needed 38 of them. > In any case, improving cost-effectiveness is surely a distraction for MCF research when there have been no advances in Q Except smaller, cheaper reactors mean you can iterate experiments a lot faster.
- manholio 4y ago> two of them could have held down the Space Shuttle when it was trying to launch. To keep the reactor from flying apart, they needed 38 And all that for a reactor that was unable to break even in energy terms, let alone ignite and break even economically. It perfectly illustrates the folly of magnetic confinement: to hold the plasma you need fields so strong and equipment so massive and expensive that the capital expenses get out of control, fully negating any advantage fusion might have over fission. We already know how to make capital intensive energy - the fueling costs are negligible for a fission reactor, yet those largely failed in the market. An even more expensive and capital intensive solution is dead in the water for economic reasons regardless of any theoretical merits.
- credit_guy 4y ago> It is likely unachievable anytime in the next half a century. It is very important for this message to get through. Fusion is not "just around the corner". By the way, the energy generated by fusion is higher than that generated by fission, but not by a huge amount. Only by a factor of 4. The energy density of Deuterium+Tritium is 337 TJ/kg. The energy density of Uranium is 81 TJ/kg. For comparison, the energy density of methane is 56 MJ/kg or more than 1 million times lower than that of Uranium.
- willis936 4y ago1 kg of deuterium is a lot friendlier to be around and less alarming to find anywhere on the planet than 1 kg of U-235. 1 kg of tritium is a hazard, but it's also more than the global annual production of tritium and any DT reactor would be engineered to have low tritium inventories and a controllable breed rate.
- credit_guy 4y agoU-235 has a half life of 700 million years. When it decays, it releases alpha radiation (Helium neclei), which is not that dangerous. As long as you don’t ingest or inhale it, U-235 is harmless. If you do ingest or inhale it, it will probably harm you more because it is a heavy metal than because it is radioactive.
- willis936 4y agoDo you know how many people you can threaten and actually kill with 1 kg of U-235?
- credit_guy 4y agoI don't fully understand where you're going with this question. Maybe you are implying a terrorist could get their hands on 1kg of U-235 and either make a dirty bomb or a nuke. A dirty bomb would not really be more dangerous than a dirty bomb made with Cadmium. As for a nuke, 1kg is well below the minimum necessary to make a nuclear bomb, which is about 15 kg. But that's not the only thing. You need weapons grade Uranium for that, i.e. Uranium where U-235 constitutes at least 85% of the whole. Civilian reactors use Uranium that is enriched to much lower levels. Currently, the vast majority of the civilian reactors use Uranium enriched to 4.5%. A terrorist who gets their hands on that, can forget about building a nuclear bomb, except if they have means to further enrich that Uranium. In other words, if they have centrifuges, like Iran does. I might remind you that Iran is a state, not a single person. In any case, if you have centrifuges, you might as well start with Uranium ore, there's no point in stealing from an existing civilian reactor.
- perihelions 4y agoHow does tokamak fusion interpolate between pure D-D and 50/50 D-T? Like, responsive to footnote cite [30], if tritium recovery falls short, could you run a sustainable D-rich D+T mixture, where D+D helps provide more neutrons for breeding tritium? Or does it only make sense to jump *all the way* to pure D+D (like the author argues in OP). What exists in the intermediate zone?
- ncmncm 4y agoNone of those will ever produce economically meaningful results. So it is only a matter of what can appear to produce any apparent results, enough to unlock further grant funding.
- photochemsyn 4y agoThis is really the most comprehensive write-up of nuclear fusion R & D I've ever come across. However, the conclusions aren't that hopeful for the notion of nuclear fusion as a useful energy source anytime soon. On the technological scale, it seems closer to the likelihood of terraforming Venus, rather than the much more feasible notion of colonizing Mars. Basically it seems like the ICF method is more effective and as an experimental system, uses much less tritium, but using it to drive a power production system (converting heat to electric power) is much more difficult than with the MCF system, if even possible. The MCF system on the other hand seems nowhere near reaching breakeven.
- ncmncm 4y agoICF is even less practical than MCF, and MCF is not. We will with certainty not get commercially competitive, or even usable, energy from fusion. Any money spent on that prospect is badly misdirected. Support fusion research to direct money to support plasma physicists, or to keep certain exotic-tech military contractors afloat, or to drive superconducting electromagnetics.
- baking 4y agoDaniel Jassby is a tiresome crank. Always quoted in the media as the sole critic of fusion. He runs a website devoted to blowing things out of proportion. In this article, he says that SPARC and ITER will both achieve first plasma around the same date (2025) but that SPARC will take another ten years to burn DT fuel because ITER is taking ten years. ITER is taking ten years because the equipment required for DT operation won't be installed until 2035, after their second maintenance shutdown. SPARC is intended to progress to DT operation as soon as possible after first plasma assuming all the equipment checks out. He poo-poos tritium breeding, referring to an article he wrote 5 years ago about the faults of a solid blanket, neglecting to mention that the ARC design has been based on a liquid blanket. If he wants to criticize the MIT/CFS SPARC/ARC design, he should by all means just go ahead and do so, but this lazy approach of his is just plain dumb and tiresome.
- willis936 4y agoThis author wrings their hands a lot and says "gosh that engineering sounds hard" and then stops there. Look at the stated timelines of ongoing projects and watch the news. Armchair engineers ought not be confident.
- leephillips 4y ago“This author wrings [his] hands a lot and says "gosh that engineering sounds hard" and then stops there.” But that itself is a useful contribution to the discussion around the fantasy of fusion energy, when the national labs are constantly seeding the media with deceptive press releases. https://progressive.org/op-eds/let-cut-our-losses-on-fusion-energy-180313/ https://progressive.org/op-eds/let-cut-our-losses-on-fusion-...
- willis936 4y agoIt isn't useful because it says "the devil's in the details but I don't know any of the details. Isn't that scary?" Are you going to make decisions based on that? Armchair speculation costs nothing if you're wrong. Also, linking your own fluff op-ed to support your point is a bad look. Consider moving the bio photo to after the conclusion.
- AddingValue 4y ago1.3MegaJoule output from 250KiloJoule on target (laser) energy 2021 August NIF https://www.youtube.com/watch?v=zWeQICvl42k https://www.youtube.com/watch?v=zWeQICvl42k
- leephillips 4y agoIn order to direct that much laser energy on target, they had to expend far more energy than the claimed output. Never forget, the laser system is far less than 10% efficient.
- deleted 4y ago[deleted]
- collaborative 4y ago> There are two broad approaches toward achieving terrestrial fusion. In magnetic confinement fusion (MCF), magnetic fields are used to confine the hot fusion fuel in the form of a fully ionized gas or plasma that persists for seconds or longer. In inertial confinement fusion (ICF), laser or particle beams are used to compress and heat a tiny capsule of fusion fuel to generate a micro-explosion of a nanosecond duration. I thought there were now 2 more: projectile method via gas gun and piston containment of molten lead
- credit_guy 4y agoThere's an even better one that for some reason gets ignored all the time. Fusion-fission hybrid. Use a fusion reactor that is well below break-even as a neutron source for a fission reactor. Currently all fission reactors have a common safety problem: their fuel has to be very nearly critical. More precisely, there are 2 types of criticality, delayed criticality and prompt criticality. Prompt needs a higher concentration of fissile material than delayed, or delayed needs a higher amount of moderator (like graphite rods) than prompt. In any case, you absolutely don't want your reactor to become prompt critical. It did happen at Chernobyl, but I think you don't want to be in that company. All reactors need to be just ever so slightly above delayed criticality some of the time. You can think of it as the R0 for Covid. When R0 is above 1, the disease spreads exponentially. If it's below, it dies down. You want it at a constant level. In this case "disease" is fission. You need R0 to be slightly above 1 a bit of the time, and slightly below 1 some of the time, so the fission keeps going, but does not go out of hand. The thing is this narrow band around 1 needs to be really, really narrow. We are talking 0.999 to 1.001 or so. Why? If for Covid a generation is about 3 days, for nuclear fission, a generation is about 1 millisecond (delayed fission, not prompt one; for that one, a generation is about 10 microseconds, which the funny guys at Los Alamos called "one shake"). If you have an R0 of 1.01, then after 1 second (1000 generations) you get 22000 more fission, and after 2 seconds you get half a billion more fission events than at time 0. That looks an awful lot like an explosion. Keeping the R0 in a very narrow band is not that easy. It is for sure doable, and that's how all reactors work. But the specter of R0 going to 1.01 is never that far away. But a fusion-fission reactor can achieve just that. The fission part of the reactor can be kept well below R0=1. You can keep it at 0.98 for example. And then you need to provide an extra 2% of neutrons coming from the fusion part of the reactor. If anything goes out of hand, you just shut down the fusion reaction, and the fission reaction dies down right away. [1] https://en.wikipedia.org/wiki/Nuclear_fusion%E2%80%93fission_hybrid https://en.wikipedia.org/wiki/Nuclear_fusion%E2%80%93fission...
- FunnyBadger 4y agoFusion energy has been "coming in 5 years" ever since 1960. Just like Gallium Arsenide will replace Silicon. Except neither has happened and the reasons are physics!!
- alasdair_ 4y agoThe reason for literally everything is “physics”.
- 77pt77 4y agoNot Godel's NoGo theorem.
- rad88 4y agoNot meaningfully. Physicists can roughly calculate how much energy will be liberated inside the reactor over its power, or a laser's efficiency, but not (for example) whether their grant money will be available in 2 years, whether oil and gas reserves will open up, in general how much oil and gas are available on Earth, the atmospheric budgets, whether some (un)friendly political group will gain influence, etc. So sometimes innovations don't work because of things like economics, geoscience, politics, funding, and other times it's fair to say that it's the physics that doesn't play. It communicates more by using an accurate word, while "everything is physics" communicates nothing at all?
- formerkrogemp 4y agoAs an accountant, the technology doesn't make sense to me, but taking nuclear fission as a case study in capital costs makes me certain that this fusion won't happen on a reasonable time scale. I'd love to be wrong though!