10 ms·
Nuclear engineer here, I can try. Before you get cosmic energy out of nuclear fusion fuel (usually isotopes of hydrogen), you have to put a bunch of energy int
by acidburnNSA 4y ago
Nuclear engineer here, I can try.
Before you get cosmic energy out of nuclear fusion fuel (usually isotopes of hydrogen), you have to put a bunch of energy into the fuel to get it into fusion conditions. Namely, you have to heat it up and compress it so the nuclei get close enough to fuse (after which they'll release energy).
There are a few milestones along the way to commercial fusion energy:
* Get more energy out of a fusion fuel than you put into it
* Get more energy out of fusion fuel that it took you to make the energy you put into it
* Build a way to capture the net gain energy and convert it into electricity
* Demonstrate the integrated power plant as a prototype system
* Build and operate the first commercial power plant
* Assuming good economic and technical performance, start building a fleet
* Deal with fleet scaling issues
* Profit!
This is a celebration of the first bullet.
- zikero 4y ago> * Get more energy out of fusion fuel that it took you to make the energy you put into it What does that mean if the cost of energy is 0 ? (e.g renewables)
- aaronblohowiak 4y agoThen why build a fusion reactor?
- giantrobot 4y agoThere's a few reasons as I understand it, the power output can be on the same order as a nuclear fission plant. So a single plant taking relatively little real estate can output gigawatts of power to the grid. The fuel is abundant to the point of being practically unlimited. The fuel also needs little in the way of refinement and is not hazardous. A fusion core is naturally fail safe since energy and fuel need to be constantly applied, an accident might destroy a core or plant but not irradiate the surrounding countryside.
- prox 4y agoIt could quite literally save the world in terms of clean energy. I can understand why one would at least try.
- ncmncm 4y ago100% false. As with fission, most of the operating costs would have nothing to do with buying fuel. Solar and wind power suffer none of these costs, so fusion, like fission, would be wholly unable to produce power at a price anyone would pay without being forced to. The fission plants still operating will find themselves increasingly unable to produce power at a price anyone will pay, so will be mothballed long short of their design life.
- ehvatum 4y agoGenerating electricity from sunlight and wind is anything but free. I prefer to pay $0.12/kWh for nuclear energy, as compared to $1.75/kWh for wind or solar, in fact.
- ncmncm 4y agoIf you know you have to lie to make your case, what does that say about your case? And, who do you imagine you are fooling?
- ehvatum 4y agoI don’t follow. If anything, the nuclear energy electric rate I quoted is too high. Regarding Diablo Canyon nuclear plant: “The plant produces electricity for about 6 cents per kWh, less than the average cost of 10.1 cents per kWh that PG&E paid for electricity from other suppliers in 2014.” https://en.m.wikipedia.org/wiki/Diablo_Canyon_Power_Plant#:~:text=The%20plant%20produces%20electricity%20for,from%20other%20suppliers%20in%202014 https://en.m.wikipedia.org/wiki/Diablo_Canyon_Power_Plant#:~....
- panick21_ 4y ago
- bell-cot 4y agoPrestige, social status, bragging rights, money (a $billion is table stakes for fusion reactors, so a lot of folks are getting fat cuts), and cool & cushy high-tech careers. Really expensive research has been going on for 50+ years now, with no sign of development - let alone deployment - of actual, practical power reactors.
- ncmncm 4y agoThere are many reasons to build a fusion reactor: It keeps hot-neutron physicists, who you must recruit from among for weapons work, busy. It provides continual practical challenges to plasma fluid dynamics physicists, who otherwise have great difficulty funding experiments. It provides cash flow to the (chiefly) military contractors who build the test apparatus. In this particular case, it lets you conduct tests for thermonuclear weapons concepts paid for out of a different budget. Any expectation of ever getting useful energy out would be the worst reason, because there will never be one solitary erg of that.
- upwardbound 4y agoThe reason I'm personally most excited is interplanetary or even (generation ship) interstellar travel. Fusion fuel is the only practical fuel we know of with enough energy density to provide enough "umph" for long-distance trajectories to be traveled along, at speeds faster than what the Voyager probes had to achieve using multi-year planetary slingshot trajectories. Fusion rocket information: https://en.wikipedia.org/wiki/Fusion_rocket https://en.wikipedia.org/wiki/Fusion_rocket https://www.iter.org/newsline/-/3303 https://www.iter.org/newsline/-/3303 http://www.projectrho.com/public_html/rocket/realdesignsfusion.php http://www.projectrho.com/public_html/rocket/realdesignsfusi... A supplement to a fusion power plant: https://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_Rocket https://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magn... http://toughsf.blogspot.com/2019/10/the-expanses-epstein-drive.html http://toughsf.blogspot.com/2019/10/the-expanses-epstein-dri... The only fuels that could achieve better energy density than fusion fuel would be antimatter, or maybe some fanciful sci-fi thing we may discover down the line, such as quark fusion ( https://www.sciencealert.com/new-quark-fusion-releases-significant-energy-won-t-make-weapons https://www.sciencealert.com/new-quark-fusion-releases-signi... ) or subatomic compression ( a concept from fiction that involves packing an immense amount of solid electrons together so tightly that the electrostatic repulsion functions as a compressed spring (perhaps using mutual gravitation almost but not quite strong enough to be a black hole as a way of preventing disastrous spontaneous decompression) ).
- elteto 4y agoIt’s not the source of energy that has a cost, it’s the process of actively capturing it, conditioning it and providing it that does. Therefore, providing energy, no matter the source, always has a cost.
- acidburnNSA 4y agoWait, are you suggesting that renewables will make energy too cheap to meter? I've been waiting for this moment. While renewables are making increasingly cheap generators, the overall systems involved in delivering reliable energy from them are increasingly expensive at increasing scale. Check energy costs to customers e.g. in Germany. Mining, energy storage, transmission, demand control, recycling, maintenance, land rights, etc. for any energy source at world scale will continue to cost well >$0. For nuclear fission, fuel cost is only 5% of the total cost. For renewables, fuel cost is 0%, but that doesn't mean there aren't costs.
- throw827474737 4y agoAh come on that wouldn't have been necessary... energy costs could be a lot lower if the path towards renewables hadn't been blocked and undermined for years, if something in the current situation is keeping it not from exploding more it is the renewables. Please better check France for the often touted right way of going nucelar, with half of their overaged reactors taken off the grid due to failing safety regulations (which are not too hard but have been dangerously softened over ye years..), cracks and corrosion problems, and their unfolding catastrophe in regard to nonavailable cooling fluid, which is a problem that will only become much bigger in the future years. Also don't distract and mix energy with energy, if something we have a heating and fuel problem, not electeicity. Secondly our gas reservoirs are already 75% filled again ahead of plan surprise surprise.. seems the lasts months panic had a little bit too much agenda involved. If you ask me energy prices here are still much too low for what is upcoming and humanity should really focus on... this will make current debates so absurd and laughable, not getting it. Why not look at some other examples who fully went renewables and doing it succesfully? Stop looking at a wanted or at least easily prevented politic, lobbyism and incompetence failure, that now leads to prices that are still much too cheap for what our wastage of resources should actually cost, lol.
- acidburnNSA 4y agoI'm stating a simple concept, which is that if you put some wind and solar into a heavily-fossil powered grid, the first 30% wind and solar are easy, and the last 30% are harder. But if you do 100% wind and solar, then you have to start spending money on things other than generators. The fraction of cost that is wind/solar generators vs. e.g. energy storage systems, transmission, recycling, etc. shifts from 1 to ~0 at scale.
- ipsi 4y agoAs far as I understand, it means something more along the lines of "This laser hits the fuel with 1MJ of energy which ignites it, but it took us 100MJ of energy to make that happen, because the laser is inefficient/only 20% of the laser hits atoms/etc, etc." Step 1, in this case, is producing more than 1MJ, and Step 2 is producing more than 100.
- MichaelCollins 4y agoImagine you 'spend' 10 GW to get 10.0001 GW out, and to do it you need a massive industrial facility. That doesn't cost $0. It probably costs billions of dollars.
- vlovich123 4y agoBy renewables I’m assuming you mean wind & solar because fusion is 100% renewable. Even fission is basically close enough in that there’s sufficient easily accessible resources to power human society for eons. Additionally, solar panels and batteries use rare earth metals, so they’re technically not as renewable as fusion / fission (although to be fair I don’t know what materials go into a fusion / fission reactor so those metals may be needed there). Anyway, the cost of energy with solar / wind is obviously not 0. You have to produce the panels / windmills, perform maintenance, for solar you need to clean, etc. Additionally, the energy isn’t available always so you need energy reserves like batteries, pumped water, etc to store it for use which increases the cost further. Finally, there are energy demands that solar / windmills can’t meet where you need *really* hot temperatures. That’s why fission repeatedly is shown as the only solution to reduce dependence on fossil fuels. Fusion is great but we should be building insane amounts of nuclear reactors right now to meaningfully decarbonize our energy generation. * EDIT: Here’s a talk [1] by Michel Laverne CSO of General Fusion. He starts talking at the ~6 minute mark and explains why renewables will never see more than 10-20% market penetration. [1] https://www.youtube.com/watch?v=5zzwnt0cNXM https://www.youtube.com/watch?v=5zzwnt0cNXM
- acidburnNSA 4y agoEven fission is renewable (i.e. can power 100% of primary energy until the sun burns out) using breeder reactors, which can run with huge EROI on just the uranium and thorium traces in average crustal granite. Conveniently, breeder reactors were first demonstrated in 1952 in Idaho at the Experimental Breeder Reactor 1. The term "renewable" is such a poor word for 'long-term sustainable'. I wish we had something that didn't make everyone think we were violating the laws of energy conservation.
- panick21_ 4y agoRenewable is an incredibly dumb term. You know what was renewable, using whale oil. That's very renewable in fact, but somehow most people are against running the global economy on whale oil. Fission is incredibly sustainable in the long term. In fact, even if we mined all the easily expressible thorium volcanic activity actually continuously brings up more.
- bawolff 4y agoRenewables don't have zero (energy) cost. Wind turbines don't make themselves, solar panels involve an energy intensive manufacturing process.
- Double_a_92 4y agoIt's about practical losses. The reactor is useless if it's more effective to just use the input energy directly.
- UIUC_06 4y agoVery well said, thanks. After you do 90% of the work, you have to do the other 90%.
- ncmncm 4y agoOr, in this case, the other 90000%. This result does not bring us any nearer to civil energy production via fusion.
- quickthrower2 4y agoGood old fusion! Under such pressure. Does JWST have to result in a commercial application?
- UIUC_06 4y agoI think the general hostility is a reaction to the hype that "this breakthrough means we're closer to an infinite source of cheap, clean energy." It clearly does not. I can understand the researchers feeling unable to tell the press, "Look, this is just basic research. Like the JWST." It might lead to a massive reaction that "well, then you have to just get in line for those basic research dollars, instead of being a top-priority thing we throw money at." All those research dollars they'd be giving up!
- jjk166 4y agoThe JWST cost about 3 times as much as the NIF. The annual budget for the NIF is about the cost of 6 F-35s, which the US is acquiring 152 of in FY2022. It's not getting top-priority money.
- UIUC_06 4y agoOK, I don't think comparing research to the defense budget is at all useful, but comparing JWST research to fusion research IS. So I'll stand corrected on US money. However, ITER is a global effort, so it isn't just the US budgets we have to consider, right?
- ganzolo 4y agoExcellent explanation. Thank you!
- prox 4y agoMaybe seen to many sci-fi, but can a fusion reactor go out of control and fuse any atom it comes in contact with? I mean with more energy going out than in. Sounds a bit like a nuclear reactor.
- pfdietz 4y agoThe main way they seem to go out of control is in the schedule and budget.
- ncmncm 4y agoThe thousands of tons of molten lithium needed for useful operation would, if ever exposed to air, prove extremely difficult to put out. That would be what they might call an "expensive setback".
- prox 4y agoWhat happens if its exposed to air?
- ncmncm 4y agoThere are some great videos on YouTube about how alkali metals behave in contact with air or, for extra amusement, water. Those don't generally present superheated, molten alkali metals.
- Ekaros 4y agoIt burns very hot. Also water won't help you. On other hand amounts used are relatively minor so it isn't massively bad issue.
- pfdietz 4y agoMolten lithium (or Pb-Li) probably won't be used in magnetic fusion reactors, because the magnetic forces from induced currents in the flowing metal would cause unacceptable pressures to develop. There was hope that insulating coatings for metal structures could be developed to deal with this, but apparently even small cracks are too much.
- the8472 4y agoIs commercial ICF realistic though? Each shot needs a carefully prepared fuel pellet. To get commercial power they'd have to fire a shot per second or so. That seems like a really expensive manufacturing operation to keep it going.
- acidburnNSA 4y agoThere is an incredible dichotomy that I learned about from David Deustch, which is that things are either: a) ruled out by the laws of physics, or b) possible. Commercial ICF is in the latter category as far as I can tell. In other words, maybe?
- magila 4y agoWhile obviously true, I think it's also useful to distinguish where items in category b fall on the spectrum from "this will be commercially viable with minor refinement" to "this is three orders of magnitude away from commercial viability and we don't even have a theoretical path to get there". AFAIK energy generation with ICF is much closer to the latter than the former.
- panick21_ 4y agoNot sure I agree. Fusion solves non of the problem of fission actually has. - Will Capx be lower compared to a advanced fission plant. Almost certainty not. - Will Fusion plan be significantly cheaper to fuel. Almost certainty not, uranium and thorium are available in waste quantities. - Will it solve proliferation concerns? No, if you have a control of a fission reactors you have the potential to do all sorts of things. - Will it solve the nuclear waste issue. Maybe slightly but advanced fission can produce waste that need to be stored for around 300 years and that is not actually that difficult. And that is of course if you assume that the 100s of billions in investment required will not have be be paid back in any way. That is partly fair because fission didn't have to do that either, but there the investment is shared with nuclear weapons (for better or worse). So I would say its closer to the second suggestion. I don't see a theoretical path of how a fusion reactor can be built cheaper then a comparable fission reactor. But I'm not a expert on fission, I have heard of some fission that could be built very small but all actual real designs for suggestion of commercial fission I have seen do not fall into that category.
- tomp 4y agoHas the first bullet (“ignition”) been achieved before, or is this the first time?
- oofbey 4y agoThis is not the first time. But it’s the biggest net gain so far by a good wide margin. Still a very long way to go before becoming similar to a fossil burning power plant. They got equivalent of 1 megawatt for a single second. A typical coal plant is hundreds of megawatts continuously.
- _ph_ 4y agoYes it has. For example JET achived 16 MW of fusion power output in 1997. (https://en.wikipedia.org/wiki/Joint_European_Torus https://en.wikipedia.org/wiki/Joint_European_Torus) Its successor, ITER is supposed to produce more energy than used in creating the fusion process. It is still under construction in France.
- alok-g 4y agoThanks a lot! I vaguely recall reading a long time back that managing the emanating free neutrons was also a challenge. Has that been solved?
- ncmncm 4y agoVery far from: no one is working on it. They know it would be a waste of time.
- ivoras 4y agoThanks for the great explanation! Would you mind answering a layman's question on where the energy comes from in fusion: my understanding is that the problem here is that energy has to be put in to overcome electromagnetic repulsion between atom nuclei so that the strong force can take over and combine them into a new nuclei, releasing energy at that time. Is this interpretation correct-ish?
- einpoklum 4y agoSomewhere between the second and fourth bullet you need to significantly limit the process' energy overhead (almost certainly, heat) to something manageable at scale. If you can't do that, then a net gain is not good enough: If you can power a town but boil a lake's worth of water with the excess heat, that's not much of a viable process.