I'm not seeing any top physicists working in this program (McGuire is not one). I would be willing to bet 1000 EUR that their math and modeling does not add up, or they have skipped some details.
Problem with fusion research like this is that the closer you get self sustainment or energy generation, the harder it gets and problems pile up. This project looks like many other similar projects that have gone bust. They start by solving the easiest problems first, get some funding and hit the wall.
The main problem with any reactor design is how to handle the 14 MeV neutrons produced by the fusion reaction (no mention in the article). They tend to damage the reactor and make it economically unfeasible. At this point being able to create fusion reaction is not the main challenge. It's the sustainment and economics of limiting the damage. If they really have solved all the problems and demonstrate economically sound fusion in 5-10 years, they will be handed Nobel price in physics for sure.
It's always a safe bet that the top Hacker News comment will always be "won't work, it's too hard." It's like sitting around for a year trying to sell a project at my current employer, with everybody and their lead telling you "that'll never work," then you implement in a weekend and those same people start nitpicking what you've come up with. (What happened to it'll never work? "Well, your CSS isn't great.")
Honestly, those folks that stand back with their arms crossed watching you fail, and reminding you the whole way that you might fail, are the biggest pains in my ass in this profession. By a mile.
Maybe you can contribute your wisdom by going to Lockheed, instead of Internet commentary in which you bet against them?
That's hardly ever true. In my experience, Hacker News is full of people from the software field; folks whose professions are often unconstrained by physics,[1] and who have a generally optimistic "this can happen" mentality. That's why everyone here believes we'll have fully self-driving cars in 5-6 years.
In the rest of the engineering world, the answer to any question is: it'll be harder than you think it'll be (physics will beat you over the head at every step). You can cross your arms and say "that won't work" and you'll be correct 97% of the time. Fusion is something that some of the smartest people in the world, with enormous amounts of money behind them, have been beating their heads against for the last half century or more. Somebody will figure it out, eventually, but statistically, any given project is very likely not to be the one that does, and it will almost certainly take much longer than the optimists assume it will take.
Did you know that coal plants, which still make up the majority of U.S. energy production, are only about twice as efficient today than they were a century ago?
[1] Although math can be a kick in the ass too if you're working in domains where you can prove there are no polynomial-time algorithms for whatever problem you're working on. E.g. there is a reason people have been banging their heads on the garbage collection problem since the 1950's and it's still an active area of research.
> Did you know that coal plants, which still make up the majority of U.S. energy production, are only about twice as efficient today than they were a century ago?
There are certainly two ways of looking at that. The way I read your sentence it sounds very pessimistic. On the other hand, I look at that and say that over 100 year's we've managed to extract twice as much usable energy out of a pound of coal, through a variety of incremental improvements to what is fundamentally the same technology; and the world is a better place for it.
> Did you know that coal plants, which still make up the majority of U.S. energy production, are only about twice as efficient today than they were a century ago?
Given how there's a huge trade going on in CO2 emission rights (at least in Europe), that's already a thing. Less CO2 emissions (catching them, filtering, etc) means they can sell off their CO2 emission rights to other companies. (see: https://en.wikipedia.org/wiki/Carbon_emission_trading )
> Did you know that coal plants, which still make up the majority of U.S. energy production, are only about twice as efficient today than they were a century ago?
Did you know that wind and solar are already at grid parity in over half the world? And that in many large first-world countries (Germany, Australia) the price of energy goes negative during daylight hours because of the amount of energy produced by renewables?
To be clear, the price of energy goes negative because of government subsidies. For example, a wind plant with a $30/MWH subsidy can afford to run at a price of -$30.
Similarly, if you're in California and you ever wondered why your electricity bill is 2x that of any other state, it is because you are the ones footing the bill for those subsidies. Without subsidies, wind and solar are far more inefficient at a $/MWH basis.
Oil, coal, and gas is subsidized to the tune of ~$400 billion a year (2010 numbers), while renewables are around ~$60 billion a year. Renewables have a capital cost, but no fuel cost.
"Meanwhile, a recent report from the U.N. Industrial Development Organization notes that photovoltaic module prices have been falling at a rate of 15 percent to 24 percent a year for some time. In 2011, factory gate prices for crystalline-silicon photovoltaic modules fell below the $1-per-watt mark, often regarded as the point of “grid parity” for solar power. Earlier this year, they reached 85¢.
The “levelized cost of electricity” for solar, a measure of the average price of power over the lifetime of a power project, has fallen from 32¢ per kilowatt hour in 2009 to 17¢ in early 2012. These declining costs are a major factor behind an explosion in use. A report by the Natural Resources Defense Council calculates that from 2006 to 2011, wind, solar, geothermal, tidal, and wave electricity production increased from 1 percent to 2.7 percent of total US production, from 0.1 percent to 1.5 percent in China, and from 5.3 percent to 10.7 percent in Germany. One sunny Saturday in May 2012 saw Germany produce nearly half of its electricity from solar. Given the long life of power plants—often measured in decades—this rate of change is phenomenal. Again, five years ago, total global photovoltaic capacity was just 16 gigawatts. In 2011, the world added nearly twice that—29 gigawatts—of new capacity."
Note this article is from October 2012, two years ago. Renewable installations have skyrocketed, with subsidies far below what oil, gas, and other fossil fuels are provided with.
Those oil, has and coal subsidy numbers are completely bogus if they are generated from the iea numbers. Iea is just a solar/wind lobbying front - and the bulk of the numbers are made from countries like Saudi Arabia and Iran directly subsidising the cost of petrol for their citizens.
It is laughable for anyone to suggest that oil, coal or gas energy is subsidised when these numbers are calculated on wooly figures like access to land, or tax deductibility of research - the same rules that apply to all companies, software companies included.
The simple fact is that oil, gas and coal energy generates a magnitude more tax revenue than it ever gets in irritating or indirect subsidies, while the 'renewables' sector only ever takes subsidies and doesn't return net tax. This is plainly obvious based on the per mw/h cost of these technologies - there is no magic formula involved in selling something below average cost of production an making a profit, no matter how much volume you do.
You can't have your cake and eat it too. If you want to bring government subsidies for renewable into the discussion, you also have to consider the externalized cost of legalized pollution. The only defensible calculation is to look at cost per kilowatt hour excluding government subsidies and including externalized costs. That's the true economic cost of the energy source.
And coal is miserable on that front. I wouldn't be surprised if coal use is a net loss to the economy (i.e. the value of the energy generated by coal is less than the environmental cost of coal use).
I wouldn't be surprised if coal use is a net loss to the economy (i.e. the value of the energy generated by coal is less than the environmental cost of coal use)
That doesn't make any sense. Net loss to the economy? If you were to say a net loss overall, including environmental costs, I might agree.
Environmental costs are part of the economy. The cost of solar includes paying highly-skilled workers to build the panels. The cost of coal includes paying doctors to treat the resulting increase in lung disease, etc.
The problem is that we don't measure economic activity accurately, because we ignore draw-down of capital (human, natural, or otherwise). Fukushima actually increased Japan's GDP for a quarter, because the damage-response activity gets counted in GDP while the loss of physical capital does not. Fossil fuel use suffers from this problem in two ways: 1) the value of the capital removed from the ground isn't counted (i.e. nobody counts selling off their family furniture as net positive income, but resource-rich countries count selling off oil or minerals as such); 2) the loss of human and environmental capital is ignored (strip mining mountains causes rain to wash away river banks, and that's money directly out of someone's pocket).
Even then, it's not a net loss to the environment.
Coal is an energy dense naturally occurring product. The environmental damage from coal relates to mining, shipping and burning it. The environmental benefits of coal are that extraction, transport and burning doesn't happen to other things - ie, biomass, otherwise known as timber.
England has more forest now than it has for centuries, because a more energy dense substitute for energy was extracted (coal). In many developing countries, access to coal would be a net benefit, because it would reduce clearing and burning of vegetation, and because the ensuing affordable energy allows for more intensive food production, and the keeping of food inventories, further lessening the pressure on the environment.
Of course, everything that applies to coal also applies to natural gas even more so, and obviously to fusion even more than that. But this meme of 'coal is evil and must be stopped' ignores the reality of the situation and completely ignores the benefits of efficient energy production, especially in the case where real, persistent and preventable environmental damage is taking place because there is a lack of efficient energy productin.
Being able to externalize pollution is a subsidy. Accounting for externalized costs, coal is about parity with wind in terms of cost, though gas is ahead of both.
Agreed, but with the price of oil headed below $80/barrel, shale and other fracking operations that are expensive to operate are now going to operate at a loss (causing some producers to go bankrupt). You're going to see the cost of natgas dip down, and if enough producers go out of business, jump back up to new highs as production will have dropped quite a bit.
You realize an airplane is just an insanely complex collection of highly specialized and engineered systems? Just because they specialize in airplanes doesn't mean that the problems they have faced, solved and are still facing today are not relevant to thousands of other engineering problems.
Sure. The question remains how many of those systems and solutions are relevant to designing a fusion reactor. I think it's easy to overestimate the relevance from a helicopter point of view.
For instance, the same argument applies to a wafer stepper or 'dreadnought class' surface mining equipment. Yet it seems unlikely they are able to commercially compete on both of those extremely different specialized kinds of machines. And I wonder if a fusion reactor would be any different.
Physicists recognize the constraints on development imposed by the laws of physics.
Software professionals recognize the constraints on development imposed by entropy, information theory, and other esoteric branches of mathematics.
Rather than scoff at this article because Lockheed is making extraordinary claims without the backing of extraordinary evidence, I prefer to scoff because nuclear physics modeling and simulation software is still software. If I cross my arms and say "that has a critical undiscovered bug in it that invalidates the results," I'd be correct 97% of the time. It also has a SQL injection vulnerability, links to at least one library written 30 years ago, and was originally written by a physicist that knew a little programming rather than a programmer that knew a little physics.
Simulations are way easier to write than almost anything else (I'm a nuclear physicist who did this professionally for many years.) The reason why: physics. Or more specifically: conservation laws.
Conservation laws are the book-keeping of physics, and they act as global checks on correctness. If your code conserves energy, mass, particle number, charge, momentum, etc it is probably correct in the ways that matter, because it's incredibly hard to get bugs that get the physics wrong in materially interesting ways while still obeying conservation laws.
I once wrote a rarefied gas dynamics simulator (modelling a few thousand interacting particles--I was curious about some non-equilibrium thermodynamics questions) that conserved energy to +/-1 bit in double-precision (and which exercised the weird feature of some x86 processors that had something like 80-bit internal registers but did 64 bit double precision computations, and which allowed the garbage in the extra bits to contaminate the LSB, resulting in very slightly different behaviour in debug and release mode, which gave me fits for weeks.) It is just incredibly hard to get that level of conservation and still get the physics wrong.
And then there's semi-analytic solutions: to check that gas dynamics code I wrote a super-simple analog of the system in Perl based on approximate equations of motion, and got the same results. Because the underlying physics admits of different computational representations that are guaranteed to be the same if they are both correct and extremely unlikely to suffer from the same bugs you can have a very high degree of confidence in their correctness.
So no: the results of simulation are not wrong 97% of the time. I've worked on one experiment where the modelling was wrong, and which took three different computational approaches to sort out, but it's a rarity.
My feeling, based on experience, is these guys are onto something very interesting.
You are simply skeptical for different reasons than I have.
As a software professional, I have been explicitly instructed to alter a program solely for the purpose of making the output more palatable for customers and investors, at the expense of real-world accuracy. And I did it, because as much as I dislike dishonesty, I also hate searching for new jobs and thoroughly enjoy sleeping under a roof and not starving.
Did the simulation that you wrote have a check for conservation of professional ethics?
You have a great advantage in that subatomic particles are unable to lie to you. Software developers have a capacity for deception exceeding even that of accountants, and we are sometimes asked to use it in unethical ways. One might think that there are reasonable limits, but we still have electronic voting machines that are mysteriously unauditable, and software trading agents programmed to automatically front-run institutional investors.
While the 97% figure was simply made up to mirror the ancestor post, it is possible that all those programs that are not accidentally wrong are intentionally wrong. In your case, you can rule out ill intent for the software you wrote yourself, but as there are potentially hundreds of millions of dollars in funding at stake for this fusion "discovery", I would not discount it for any simulation that suggests this device will work.
...and which exercised the weird feature of some x86 processors that had something like 80-bit internal registers but did 64 bit double precision computations, and which allowed the garbage in the extra bits to contaminate the LSB, resulting in very slightly different behaviour in debug and release mode, which gave me fits for weeks...
FWIW, this is a compiler error. Most x86 processors have 80-bit extended floats, which allow 64-bit "pow" to be computed in software with low error (among other benefits). Some compilers "helpfully" compile for 80-bit mode with some combinations of compile options. They should never do this unless it's specifically asked for using a single command-line option, partly for the reason you discovered: it totally messes with replicability. It also messes with implementations of "log1p", Kahan summation, and other high-precision algorithms like double-double arithmetic.
If you ever come across this again, submit a bug report.
The question is, what did they simulate and how? A full-on dynamical plasma simulation of the entire machine is intractable, and every approximation technique has its blind spots.
Among people who have a common mindset, yes. But in general people don't like to take risks or expend insane efforts to make something happen. When they see others doing it, they like to stop them. Generally its because they don't want the regret 'They tried and got it, If I had ...' Or they are plainly jealous and can't stand some one else do progress.
Even pg discussed the phenomenon, as you undoubtedly know. There's a good idea, or a news article hailing progress, or some other kind of optimism, then the first comment is a mid-brow dismissal. They are the lowest-effort comments to make; "that won't work because X isn't well-respected and Y often happens to similar teams" requires almost no research and cannot really be refuted.
The only way to refute it is by calling a spade a spade, and look what I get for doing so: having my comment twisted to be fuzzy feel-good smarm crap, when really I'm just saying "shut up and get out of the way if you don't think it'll work."
I don't think of such comments as being "mid-brow" dismissals. Indeed, the people most knowledgable about the field are the ones who are most likely to tell you it won't work. And 97% of the time they'll be right.
As for "shut up and get out of the way"--whose way exactly? Unless you're a nuclear physicist, comments expressing hopeful optimism aren't very useful.
The only solution is one that can't be applied here: LockMart shouldn't make extraordinary claims ("Check out this cool fusion reactor!") until they have extraordinary proof to go with them.
Right now, this entire story is just a waste of space on a hard drive somewhere in Palo Alto, and no comments pro or con are going to change that.
I don't know about that. What you are suggesting doesn't really fit the MO of Skunkworks where they work on advanced projects for years before revealing them. It's not like they announced stealth aircraft in the 90s just to drive up their stock price, they'd been working on it for nearly 4o years by that point and the planes were flying missions for decades.
With a fusion reactor, the only proof that's adequate would be a press conference at a facility where there's a large object under a tarp and a big red button to push. By itself, a press release on the subject just doesn't convey any actionable information, no matter what it says or who it comes from.
And it's always a safe bet the top response to that comment will be somebody criticizing it without any solid facts or reason but with fuzzy "you just need to believe harder!" kind of nonsense.
Actually, I subtly said "get the hell out of the way if you don't think it'll work," not warm and fuzzy smarminess. But it's much easier for you to mock if you read warm and fuzzies out of it, and I get that.
What I said, reworded, was the people who sit on the sidelines of anything and tell you, while you are trying something, that it won't work are among the worst people in the profession. I didn't say believe harder. I don't give a damn what you believe and don't need you reminding me, constantly, that my project has a chance of failure. Keep it to yourself or get on board. That's my point.
I am not a kind person, so that you'd ascribe feel-good nonsense to me is downright hilarious. I can handle it but a lot of people can't, and it's really, really tiring to keep a team from becoming demoralized when there's a naysayer popcorn gallery in every thread and watercooler discussion.
The naysayers do us all a valuable service. They remind us that hope, dreams, and belief do not solve engineering problems.
You know what demoralizes a team like nothing else? And endless litany of projects that failed because nobody wanted to listen to the people pointing out problems.
You know what demoralizes a team EXACTLY like that?
When people on the team think they are pointing out problems, but are doing so without support, by simply saying "That won't work" instead of "That won't work because of ...".
This does nothing to further a project and leaves the burden of proof for a working solution on the person who proposed the solution in the first place, and the way for them to prove their solution is to continue working on it, with no actionable feedback to revise their project on.
It is also a safe bet that the response to the original comment's response will be some guy saying how being hopeful about something is complete nonsense.
It's turtles all the way down. Guess we should just give up on Internet commenting. /s
Interestingly, the heat for this pattern is always taken by the last comment, for some strange reason. Maybe it's the communities way of saying "Duh, we know this happens, and the way we stop conversations from going down the meta-toilet is to not have them." Although I would say it's more fair to downvote every comment that fits the pattern, to the root, rather than just the latter ones.
I dislike negativity as much as the other guy but fusion specifically has been "10 years away" for the last 60 years. I'm not convinced, especially without any specifics about what improvements they made. Probably just another grab for funding.
I think people here are generally willing to believe that this is solved if the hard problems are solved. Right now the skepticism is that the hard problems haven't been solved - but that's true of any bet that you make. Either the hard problem has been solved, or you're betting that your people will solve it soon.
Thank you for your detailed explanation of why people should not make any attempt to apply their judgment, experience, or knowledge of the world to press releases, and instead accept them uncritically.
"There aren't any top physicists working on this project" isn't really enough to dismiss it outright. The number of brilliant physicists is much greater than the number of top physicists, so it's not unheard of for major developments to come from someone who's not yet highly recognized. McGuire's an MIT Ph.D, so it's likely he's not a complete idiot.
I hope they have some novel ideas about neutron containment, though, otherwise you're right and this is project is not likely to yield the first economical fusion reactor.
>McGuire's an MIT Ph.D, so it's likely he's not a complete idiot.
obviously. The proposed reactor looks exactly like a great PhD thesis with honors - a novel field configuration proposed which allows to reach beta of one. The rest of the whole system is given only cursory treatment. In particular how about a "neutron absorbing blanket" in a business-jet size envelope?
"Top physicists?" Fusion is an engineering problem.
The thing to check here is what plasma temperature/densities they have achieved with their new confinement scheme. They've basically said the results are preliminary, and some of the results are from simulation (which should not be trusted; aka look at how well the NIF simulations worked). This is not particularly interesting.
Shielding was mentioned, though not enough, but it's fairly trivial: if you add enough matter with a high neutron cross section (paraffin for example), and build the mechanical components out of things with a low cross section (iron, I think) it's not a problem. Plasma is the problem.
It's interesting, but "10 years off" is not much better than the standard "20 years off" promises of fusion research. As others have pointed out, controlled fusion has been 20 years in the future since 1950 or so. "1 year off" would be a lot more noteworthy. As it stands, this is just Lockheed informing us they have a controlled fusion program. Anyway, "nice press release, dudes."
> It has been suggested that most of the actual inventing was performed by Szilárd, with Einstein merely acting as a consultant and helping with the patent-related paperwork.[1]
Fair enough. There aren't many household names in physics working in that field. The closest ones to that description have their own fusion startups, like d-wave.
The Skunk works has one heck of a good reputation.
So, I have to guess that the Lockheed suits
had this guy's work and PR reviewed with a
microscope from tip to tail, math, physics,
materials, software, experiments to date, etc.,
including reviews by people who would have
loved to have found something wrong.
It's a very safe bet. Well, probably not a math error as they are quite a fine institution, but what he says is probably the case.
The challenges of fusion power are largely fundamental nitty gritty engineering issues. We know fairly well how to design most of a fusion reactor; in a lot of ways they are conceptually easier than fission reactors.
The two main hurdles are the materials problems and how to keep the reaction critical with radiative heat loss. These are big problems that so many times have been ignored by people claiming to have solved fusion power. You just can't get away from them, but solving them would be truly revolutionary.
I'm not saying they don't have something novel here as they really are some fine researchers at Skunkworks. Just temper your expectations.
> The challenges of fusion power are largely fundamental nitty gritty engineering issues.
I'm not saying they've done it and extraordinary claims require extraordinary proof but this is the place that made a Mach 3.5 jet with wings that leaked out of titanium in the 60's.
Nitty-gritty engineering is something they are fairly good at.
Indeed, believe me I hope I'm wrong and that fusion power really is around the corner. It's just that, according to the article, they aren't even at the prototype phase yet. That's where the real problems for fusion reactors arise. I'm sure that they've done something interesting, but my (semi-expert, I'm a nuclear engineering PhD, but not in fusion technology) opinion, this doesn't look like The Big Discovery.
Tokamaks were perfect on paper till they were fired up, and then we realized that there is a lot about high energy confinement we did not know about. So I think the math is correct according to current models, but whether those models are close enough to reality for this to work is another question entirely.
>How much dangerous are the neutrons from such device?
Fusion neutron (14 MeV) from fusion reactor is exactly as energetic as fusion neutron emitted by a neutron bomb and causes equal damage (just distributed over longer time). They have 10x as much energy as fission neutrons and travel at speed of 52,000 km/s (17.3% of the speed of light). Neutron capture before they hit and damage magnets, electronics or wear out materials is important part of the fusion reactor design.
This is a DD machine. Neutron energies from the primary reaction are comparable to fission neutrons, 2.4 MeV. There will be some from secondary DT reactions, which are 14 MeV, but the bulk of the neutron production will be at the lower energy.
> How much dangerous are the neutrons from such device? Similar to radiation, worst?
Neutrons are interesting in that they dump all their energy into a very small region. Instead of losing energy continually and gradually, they travel a ways and then dump all their energy into one spot. This makes them potentially very useful for things like cancer treatment (you can select neutrons to ensure they deliver most of their energy into the cancer, rather than evenly along their travel path). I suspect this effect means that, for reactors, the wear and tear is more localized, but of a larger amplitude.
> I suspect this effect means that, for reactors, the wear and tear is more localized, but of a larger amplitude.
Not exactly. The initial collisions do indeed cause localised damage cascades, but the overall effect of a large neutron flux is embrittlement of the material. This is a problem already in fission reactor vessels, but the neutron fluxes are a whole order of magnitude larger in fusion reactors, and it's a very difficult problem to solve. To my knowledge, current materials can only just about deal with with the neutron fluxes in standard fission reactors, with no current materials being capable of withstanding neutron fluxes in a fusion reactor over any long (i.e. commercial) timescale at present. It would be a big achievement and a big jump in materials science to discover such a material, completely separate of any fusion project.
(Disclaimer: this is not remotely my field, but I have looked at some of this stuff in the past, and been to talks about ITER.)
It's a simple geometric analysis: neutrons can't be deflected, so whatever concentration of reacting mass you have emits neutrons isotropically. So to my knowledge no (you can only radiate more in one direction if the reaction is more extended in the perpendicular direction).
The majority of those suppliers provide boron-impregnated plastic, which is fine for e.g. shielding spallation neutrons from a medical linac head. Reactor shielding is orders of magnitude higher, so material damage is a real concern. Not to say that people can't or don't use that material, but it is not the most cost effective stuff.
Frankly, the best neutron shielding in the world, on a per-cost basis, is water with borax. I don't know why people don't use this more. We used to use stacked bags of borax as neutron shielding when I built a fusion reactor (non-self sustaining, of course), and we had more than enough shielding to handle 2.45 MeV neutrons for under $1000.
So in this reactor design, the neutron shield would be quite thin, if that drawing is to scale I'd say like 30-50cm? in that case water in borax wouldn't be dense enough right?
A cool thing about the shield being liquid is that you could theoretically replace it while it's running. It could make the neuron shield double as the heat transfer medium too.
Of course I'm a total layman so this is just highlevel blabbering.
Are you sure you're not mixing up neutrons and protons? Here are some typical depth dose curves from google images(http://www.nap.edu/books/11976/xhtml/images/p20014b2bg205001...). Neutrons, being neutral particles, don't exhibit the Bragg Peak (large increase in energy deposition at the end of the particle's track) that you get for heavy charged particles.
I was pretty sure neutrons beahved that way (recalling from a course I took in grad school), but it has been a few years, and I do not have references handy. I am not entirely sure what the y-axes are, on the plot you linked, so I am not sure how it correponds to what I was saying.
The do not. Protons have a quite definite range, and can be controlled in the way you suggest. This is because they lose energy primarily by scattering (much lighter) electrons out of their path. This means protons have relatively straight paths and the dynamics of the electromagnetic interaction gives an energy deposition curve that is sharply peaked at the end.
Neutrons slow down via interaction with nuclei (all of which except hydrogen are heavier) so they lose energy slowly and scatter all over the place. They have no definite range (search for "fermi age theory" to get a rough idea of the distribution) and can't be meaningfully beamed (unless they are ultra-cold, which is not relevant to fusion power.)
I've made a longer comment above that goes into neutron physics in a little more detail.
There are a variety of more-or-less sort-of correct answers below, but I'll throw in my two cents regardless. I am a nuclear physicist who spent a lot of time worrying about neutrons, which are a major source of backgrounds in neutrino detectors.
Two points made reply to you are correct: neutrons are radiation, but not electromagnetic radiation; and neutrons can make other things radioactive.
Some thing other people are saying are less correct: any individual neutron will deposit most of its energy in one place, but averaging over many neutrons their energy deposition will be spread out. Furthermore, neutrons will come out in all directions. The problem of neutron damage is not small, but no one seriously believes it's a show-stopper.
Neutrons are the exploding billiard-balls of nuclear physics. Fusion produces "fast" neutrons, with moderate energies. This is a deuterium-deuterium device, so most of the neutrons will come out with 2.4 MeV, which happens to be the same as fission neutrons. The DD reaction produces tritium as a byproduct about half the time, though, and DT fusion will lead to 14 MeV neutrons. There will be fewer of these in most designs, and some designs incorporate ideas to get rid of the tritium quickly to suppress these higher energy neutrons.
At high energies neutrons don't tend to interact very much with light nuclei, and for a variety of reasons fusion reactor design is dominated by light nuclei. What they do do is bounce off, which is where the billiard-ball analogy comes in. Each time a neutron bounces off another nucleus it loses energy (because the nucleus it bounces off of recoils, carrying some energy with it.) This is just pure Newtonian mechanics.
Neutrons typically travel a few metres in the process of slowing down, depending on the material. Light materials slow them down faster: a light ball bouncing off a heavy ball doesn't loss much energy, but bouncing off another light ball it does (hydrogen is the best material for slowing neutrons down because of this, and hydrogen-rich materials like water are good too.)
The neutron never completely stops because the nuclei it is bouncing off of are in thermal motion. At room temperature a neutron in thermal equilibrium moves at about 2200 m/s. But not for very long, because this is where the exploding comes in.
You can think of it in these terms: once thermalized, a neutron is passing by other nuclei rather slowly (2200 m/s is slow when you're a neutron). This gives it lots of time to react with nuclei, rather than just bouncing off, and eventually it does. When a nucleus absorbs a neutron it becomes a different isotope of the same element, and in many cases adding a neutron to a stable isotope makes it radioactive. Carbon-12 is a stable isotope that, with the addition of a neutron becomes carbon-13, and if it happens to get another neutron added later on, radioactive carbon-14.
Neutrons are a pain, even to fission engineers, and fission depends absolutely on them to happen. They get everywhere, are hard to shield, make stuff radioactive and damage materials. But we know pretty much how to deal with them, and it's unlikely they will make the difference between working and not working in a device like this.
The neutrons from these reactor makes surrounding matters radioactive? Doesn't sound too good. The fission reactor is not really as clean as it sound at first?
Putting a mice next to this system can make it a "carbon-14" mice? Can it glow in the dark? :-)
Time to buy airline stocks. If you can put a miniature fusion power plant on an 747 equivalent, airline profit margins will skyrocket.
Actually even if you believed there's a chance this Lockheed concept can work, the time to buy airline stocks would be on the back end of this dead bull market that's about to fall off a cliff. And then there's the 20 year wait before it's finally deployed to a commercial airplane.
A fusion powered 747 might be the result, but
maybe not! Instead, let's see: With the CFR,
we've got dirt cheap electric power. Okay,
then we can also use that power to make dirt cheap,
very clean water. Then, yup, we can take that water,
more of that power, and coal and make jet fuel.
And maybe that is what the 747s would continue to
use! Maybe!
If we get a working CFR as described, I'd be shocked if the cost of coal extraction and usage remained low enough for this to be a sound idea. In the face of extremely cheap, clean power, I'd sincerely hope that the government would incentivize its use. Coal and oil lobbies might be able to fight this to some extent, but once a safe and economically viable alternative is present, the days of fossil fuel reliance are numbered. This can't happen soon enough.
From what I've read at just the level of
Wikipedia, I'd guess yes. But nuclear
physics just is not my field.
I wanted my Ph.D. in mathematical physics,
but all the physics courses I could find
did the math in very sloppy ways, and my
hope for any research progress in physics
wanted to do the math with full care. I
did get much of that math, but by then
I was occupied with my money making work
and didn't get back to physics. I'd like
to, maybe, someday! Then maybe I'll be
able to give you a solid answer.
For now, some of the discussions claim that
a lot of neutrons will make a metal brittle
but don't go the next step and explain just
why. Before I'd say anything about what
neutrons do, if only as a check on the level
of understanding, I'd want to know why.
Whatever production process partially relies on arranging the crystal structure of the metal to arrive at desirable properties, the neutrons disrupt it.
Okay, I'll accept that: What used to be
the usual isotopes of iron, carbon, aluminum,
etc. with some extra neutrons, after
whatever gamma rays, alpha particles, etc.
boil off, becomes some other isotope or
element that doesn't fit in the crystal
and, thus, makes the crystal brittle.
It can happen without neutron absorption, the neutrons simply knock the atoms out of alignment, and they bounce around a bit (so each neutron can cause more than 1 defect).
(if it doesn't follow why that would matter, look into the heat treatment of steel)
"As Tom McGuire, who is leading the Lockheed team, notes, however, the circular magnetic fields which coil around a tokamak’s doughnut become unstable if the plasma’s pressure is too high."
If you have to periodically throw away your reactor and buy a new one because of neutron damage that would be a positive thing for a company like Lockheed.
You can't stop progress just because it alters your cash flow. If you don't make the product, someone else will, and end up positioned to take the future cash flows. No (rational) company stops investing in new products just because it challenges their current offerings.
Oil wars are old hat. They were useful for bootstrapping the system, but now that that is done we don't need them anymore. Oil wars are not preferred because they are fairly transparent and therefore give bad approval ratings for politicians.
The new system: Find a war torn area (perhaps one decimated by oil wars), dismantle their army and replace it with a wildly incompetent one. Make an earnest but fruitless attempt to train them (how humanitarian!). Give them American weapons (cha-ching) without actually solving any of the issues that were destabilizing the region. Local strive escalates to war, the incompetent army is crushed and their American weapons are seized. Use American owned and operated weapons (cha-ching) to bomb the seized American weapons back into the stone age (how humanitarian!). Rinse and repeat.
War machine get's their money, and the politicians get to pretend that they are only trying to help others.
Maybe the trick is that the reactor design is either cheap enough to be disposable, or just lasts enough to run a submarine for a few months (not necessarily in an economical fashion, but with other desirable advantages) and have it replaced like a car battery.
>I'm not seeing any top physicists working in this program (McGuire is not one).
McGuire is a top physicist - he is currently working on a compact fusion reactor at Skunk Works, which came out with the SR-71 Blackbird among other innovations.
Oh, did you mean, ones who had already succeeded in their top projects? Well, how do you think they got to succeed - by not doing it?
I know there are some very smart people at skunk works who've done incredible things in the past but humans have cried wolf so many times on fusion it's sort of hard to just accept until they've actually built a working reactor, shown it and had it independently verified.
Fusion physicists I know are very sceptical that this design can work. It's a variant on a known design with a known problem: the plasma leaks out of the ends of the magnetic containment. It's also unclear why Lockheed would be publicising it this way at this point, unless it's a naked ploy for more funding from the DoD, and an attempt to bring in money (and possibly pressure) from non-classified sources.
That being said, if they've genuinely cracked it, the game changes so much as to be unrecognisable.
From the Aviation Week article that flexie linked:
"The team acknowledges that the project is in its earliest stages, and many key challenges remain before a viable prototype can be built."
They don't actually say it, but it sounds like they've only got computer models to work with at this point. Not very likely that they've actually cracked it.
Push the oil and natural gas markets lower, pile on all the other factors pushing them down right now, and further harm Russia's economy.
I'm half joking, but I'd keep an eye out for more unusual energy related press releases, to see if that'll confirm that it's a media blitz aimed at the oil market etc.
For what it's worth, in the Google [X] talk last year, they briefly mentioned running actual plasma confinement experiments (although I guess not reaching fusion conditions or that would probably have been publicized).
> the plasma leaks out of the ends of the magnetic containment
According to this link[1] posted by another commenter, they create a "axisymmetric mirror by positioning zones of high magnetic field near each end of the vessel so that they reflect a significant fraction of plasma particles escaping along the axis of the CFR."
When you're dealing with a plasma at 20 million kelvin, the leftovers from that "significant fraction" that don't get reflected can really ruin your day...
LLNL scientists almost tested a similar device (see 'MFTF') but the project was cancelled in 1986 before it was turned on.
It is possible though that though earlier attempts failed because the computational resources and the plasma dynamics modeling available at the time were not sufficient to design such a reactor.
I would guess that we have a much better understanding of plasma physics and faaaaar greater ability to model it now - that could lead to designs that can mitigate previously discovered issues with the concept.
Historically, the problem with the cylinder + mirror configuration is that there are discontinuities (corners) at the seams where the mirrors join on at the end. So you lose a lot of plasma there. Interested to see how they've overcome that.
Maybe it's the reverse. It is a PR to make an impression that the fusion is just around the corner to discourage other nations from investments into tokamaks and improved fission reactors, out of impression that this fusion breakthrough will make them all soon obsolete.
This is a very good point. Extraordinary claims...
If you haven't hung around talk-polywell.org before, you might want to. It's focused on the polywell but they seem to at least try to fairly evaluate all contenders.
New confinement techniques (NIF, this article, Helion, Polywell) are actually making real progress. So it's becoming less likely that an announcement like this is 100% vapor.
Put another way, we're getting to the point now where we have tools sufficient to actually know what the results will be. That, more than anything, is the benefit from the billions spent on tokamaks.
The AviationWeek article even mentions that the LMSW team drew from Polywell:
> "We also have a recirculation that is very similar to a Polywell concept," he adds, referring to another promising avenue of fusion power research. A Polywell fusion reactor uses electromagnets to generate a magnetic field that traps electrons, creating a negative voltage, which then attract positive ions. The resulting acceleration of the ions toward the negative center results in a collision and fusion.
It's great that they've scoured even the non-mainstream ideas and incorporated them.
It doesn't talk about how recirculation is used. I was thinking maybe it has something to do with sealing the cylinder end caps, to keeping plasma loss to near zero?
I followed the ecat (http://ecatnews.com/) story for a year or so until my BS alarm started getting really loud - but just the prospect of it was so exhilarating, it was hard to resist the enthusiasm overflow...
Now this sounds way more serious than Andrea Rossi's saga. But I did get a lot tougher on my wait and see stand.
> U.S. submarines and aircraft carriers run on nuclear power, but they have large fusion reactors on board that have to be replaced on a regular cycle.
sigh To the extent this is true I suspect those "large fusion reactors" are tuned not so much for generating electricity and a great deal for annihilating whatever the carrying missile is pointed at.
But never mind fuzzy thinking at Reuters right now. This is amazing news if holds up. Fingers crossed.
> U.S. submarines and aircraft carriers run on nuclear power, but they have large fission reactors on board that have to be replaced on a regular cycle.
Even the need for regular replacement went away long ago. Our current (old) designs get refueled only once, and new ships don't get refueled at all (the core lasts as long as the hull does). They do all need regular maintenance, but that's true for all U.S. warships.
He's making a joke about how fusion has been used successfully for decades, but only for bombs. Thus, aircraft carriers and submarines do have fusion devices on board, but they're only used for destructive purposes.
Maybe you're just less bothered than I about the writer conflating fission and fusion when the difference between them makes for a good deal of the newsworthiness of the article.
I'm well aware of the fission reactors in large military ships, but if there is any application of nuclear fusion on them then pretty much the only option today is thermonuclear warheads. It would be really nice if that's about to change.
Most warheads have hollow plutonium pits that are filled with tritium (right before implosion) triggering a fusion reaction from the high heat of the plutonium fission reaction. So no, it's not only the H-Bombs, though those are primarily fusion while tritium is only used to "boost" classic implosion fission warheads.
Civilian power reactors need refueling at about that pace, but Nimitz-class carriers "are capable of operating continuously for over 20 years without refueling"
I believe you're misunderstanding, those ships run on power generated by a nuclear reactor. A reactor is like when you think of a regular nuclear power plant, it's not part of a missile.
Helion here. There are pretty big differences. They did get the high Beta and compact/modular parts right. The primary differences are that Helion operates entirely pulsed with simple non-superconducting magnets. That allows us to go to higher temperatures, cleaner fuels, directly recovery energy, and if everything works as planned should eliminate the wall concerns and need for particle beams.
I do think what they are doing is interesting. If its like the Gas Dynamic Trap or Tandem Mirror it has promise, atleast from the fundamental physics point of view. Researchers in Novosibirsk had encouraging results in the last 5 years. They still have a long road ahead to get to fusion-relevant temperatures, but we are staying tuned to this one.
If you really are Dr. Kirtley let me say you have one of the most, if not the most important job in earth right now. Fusion energy has the potential to stop wars and re-start the space revolution. I wish you the best.
I'm all about the space revolution, but the only way to stop wars is to have one so big there is no one left to wage them. In a way, fusion does have that potential, but I suspect you were going for something more positive.
Of course it will not stop all wars, but it will stop most oil-related wars. You still will have resource-related wars like cultivable land, and fresh water but with the space-revolution soon humanity will have plenty of land and water too.
Well... if fusion energy is abundant, the price of oil will drop rather abruptly. A lot of people in a lot of places, where the population has been expanding, and there is a lot of religious extremism and political instability and modern weapons, will have to find a new way to feed themselves. And someone to blame if they can't. So I'm not that optimistic it will stop any wars.
Aha thanks for the explanation, that does make things clearer. Also a huge thanks to you for being at the forefront of technology. I consider energy research the single most important thing we can do for humanity, and I'm incredibly grateful to see real progress on fusion in my lifetime.
AFAICT, ²H + ²H produce ³H (which is the burned), H, ³He, and ⁴He, plus some neutrons and gamma rays. The latter must bring the energy out of the chamber, by heating some blanketing. Then it must be the same as with fission reactors.
From the article Flexie posted, for production they're planning to use deuterium-tritium, which produces helium and high-energy neutrons, which breed more tritium from lithium. Like most fusion projects they use deuterium alone for testing.
Basically you catch electrons flying out of the plasma arc (where fusion is taking place), and ground them back into the plasma (which is positively charged).
This might work. It's from Lockheed's Skunk Works, which has a very good track record and tremendous respect in the aerospace community.
With the basic physics laid out, this is mostly an engineering and construction problem. Their plan is to build and test a new prototype every year. The Skunk Works can do that; they've been doing it for decades. They're a manufacturer of prototypes, and have in-house capabilities for building things fast. They don't have to contract out much, and where they do, they have a contracting operation and supply chain they can rely on.
That's definitely true, and it's nice to have another set of brilliant engineers working on this problem from a somewhat different angle than that taken by previous brilliant engineers. Personally, I've become somewhat disillusioned with ITER after reading so much about their bureaucratic hurdles... but maybe they have enough talent onboard to pull it off anyway.
I have not seen any "basic physics" laid out at all about this concept. Namely, how do they keep the plasma from leaking out the sides of the mirror? What calculations/simulations have they done?
As long as they remain secretive, they have no right to demand to be taken seriously.
> 100-megawatt reactor measuring seven feet by 10 feet, which could fit on the back of a large truck
A typical thermal power station has an efficiency below 50% for electricity generation, so the plant dissipates at least as much heat as it generates electrical power.
I wonder how you could get rid of 100MW of waste heat from a volume small enough to fit on a truck. That's a heat flux of more than a megawatt per square meter of surface area.
FWIW, a single Boeing 747 engine does about 100MW. Such an engine can be considered to "fit on a truck" for some definition of truck.
Also consider that much of the size is due to the fan on the front (which is not part of the actual engine power plant), which makes the engine's area in the plane transverse to the axis of rotation seem larger.
However, jet engines have the advantage of burning their fuel directly in the air that is flowing through the engine, which results in an extremely rapid transfer of heat to the air compared to other (this is why 10 Boeing 747 engines == 1 GW coal/nuclear plant which is "buildings" in size).
That's an excellent point! Perhaps they intend the truck to be sitting at the bottom of a fast moving river.
But what gets me is that they are burying the lead. No fusion reactor of any size has reached sustainability...so why is the story here talking about size at all? Small size would be a very nice added bonus; fusion reactors that don't consume more energy than they produce are earth-changing.
What the commenter is pointing out is that it may not matter how you cool the reactor. It could be in interstellar space and it might not matter because the material the reactor itself is made of may not be able to transmit the heat away from the reactor. And no such material may exist.
I agree that the announcement is a bit burying the lead here, though maybe the size is actually important to making it work. From Aviation Week[0]:
"But on the physics side, it still has to work, and one of the reasons we think our physics will work is that we’ve been able to make an inherently stable configuration.” One of the main reasons for this stability is the positioning of the superconductor coils and shape of the magnetic field lines. “In our case, it is always in balance. So if you have less pressure, the plasma will be smaller and will always sit in this magnetic well,” he notes."
As far as I understand this (IANAP), they're saying that smaller size = less pressure, and that helps their design to work (in theory).
I think it is more a matter of tolerances than of size what makes ITER take so long. Also, it is experimental. That means that it is not just a matter of ordering stuff and putting it together.
Note that it converts ~100kW thermal into ~37-47 kW electric. It also has high air flow. I suspect that means that they are aiming to make their fusion reactor small enough that it can replace the burner section of the turbine.
Thermal transfer is still going to be a challenge, unless (Idea!) they are planning on spraying water into the airflow and using heat from neutron moderation in the water to provide primary heat transfer. Hmm, I wonder how much water you would need for 14 MeV neutrons? Let's see, half-value layer is around 10 cm, so if you threw a 40 cm thickness of water across a neutron flux, you'd absorb most of the heat (you could probably catch the rest in the duct casing). That's a lot of water in a pretty small space, but physically possible.
Note that the above is a seat-of-pants calculation and should not be taken as accurate by any means.
The Bugatti Veyron 16.4 has 1200 hp and therefore probably produces around 2.5 MW waste heat at full power. A factor of 40 is still quite a difference but it does not sound like an unsolvable problem.
That's peak power, though. Basically no street car is designed to be able to produce peak power for more than a minute or two at a time, and probably very few can do it for more than a few seconds. I'm pretty sure that car doesn't have the cooling capacity to cool itself at full power like this plant would have to.
You can drive your average care at peak power for an hour without problems. The problem with the Veyron is that at top speed the tires will wear off in 15 minutes and you will run out of fuel after online 12 minutes but I think it is not really limited by its cooling capacity - at 400 km/h a LOT of air passes through its 10 radiators.
temperature difference between air entering and leaving the radiator ~ 10degC
==> 1MW
So handling 2.5MW waste heat doesn't seem out of the question from this analysis.
As another ballpark "upper bound" analysis, consider that copper is one of the most thermally conductive materials, with thermal conductivity ~ 400 Wm/(m^2 degC), let's round that up to 1kWm/(m^2degC).
Let's assume that there is a thermal conducting surface of 1m^2 (i.e. the surfaces of the pipes that interface with the radiators). Let's assume that the copper is 1mm thick (= 1m/1000). Let's see what temperature difference would be needed to transfer 1MW of heat across:
As another ballpark "upper bound", the convective heat transfer coefficient for forced air is ~ 100W/(m^2degC), which means that assuming that the radiator fins are 100 degC above the air temperature, in order for the fins to transfer 1MW of power to the air, you would need an area of
1MW == 100W/(m^2degC) * 100 degC * area m^2
==> area ~ 100m^2 of surface area in the radiator, which doesn't seem unreasonable (a radiator 1m^2 area * 10cm deep, made up of thin plates spaced 1mm apart has this total surface area).
So they Veyron dissipating ~ 1MW in waste heat at 400km/h doesn't fail any of these basic sanity tests.
More complicated though is the interaction between the stages considered here. For example, how do we interface our 1m^2 of copper with our 100m^2 of radiator? Making the radiator fins thin lets us pack more surface area into the same volume, but also makes it difficult to keep the "edges" of the fins at a sufficiently high temperature so that they pull their weight transferring heat to the air: since the "copper tubing" has significantly less surface area, it only contacts (and thus transfers heat to) the radiator fins "sparsely".
My point may not have been as strong as I thought, but that tends to support it - airplane and boat engines do need to operate at max power nonstop, so they're designed for it. Consumer automobiles usually just accelerate for a few seconds and cruise at relatively modest speed, and I'm pretty sure their cooling and other related systems are designed around that.
That's because you usually have a speed limit. If you have a car with say about 100 hp your top speed will be about 200 km/h and that is a speed you can drive at for extended period on an Autobahn in low traffic. A more powerful car will of course make it harder to keep the pedal at the metal.
In addition, in the step before where the heat is transferred away from the reactor walls to the turbines, a heat flux is needed of 100MJ/s. Assuming a contact surface of 100m2, that is 1MJ/s per m2. That sounds like a huge flux and I am not sure if there is any medium that could do this.
Normal cooling (cooling towers or similar) requires a huge structure to dissipate 100MW. The cooling infrastructure can't fit in a truck. What you can to is transport the plant to somewhere where the environment can help with the cooling, such as where there is a good supply of cold water.
One can imagine these to be simple drop in replacements for existing coal plants with existing cooling infrastructure,which would be a huge environmental win in places where those are still built.
Remembering that there's no possible way we could know how many years away a thing is; the numbers are clearly a guesstimate.
They're more of a rounded (hence the clustering at or away from given numbers) measure of the remaining 'effort' versus 'difficulty'. Very likely there is some absolute time required (experiments take time to run), but throwing more people (and more importantly, more resources to run experiments and gather data) at the problem /would/ get to an end result faster (though how much faster is open to debate; it's sort of like asking how much effort does it take to win a top 30th percentile prize from a lottery).
What's different this time (yeah, I know, I know) is that, if what they and EMC2 are separately claiming is true, it's gone from being a fundamental physics problem to relatively tractable engineering, with well-understood risks and timelines.
Compare this with ITER, where they still don't know what material some fairly critical components can even be theoretically made of. It's just night and day.
>Compare this with ITER, where they still don't know what material some fairly critical components can even be theoretically made of. It's just night and day.
the Skunk Works and EMC2 haven't even reached the stage where they would face the same issue of material - all of them would ultimately have to contain the same type of fast neutrons and there is no good known material to do it.
That's true as far as it goes, but it's not the problem I was actually thinking of.
The problem is related to how you get rid of the post-fusion products. ITER is designed with divertor plates in the floor to scoop off the fusion ash and shunt them outside the core. My understanding is that these plates have to be a) solid, and b) capable of withstanding contact with absurdly high temperature plasma. There are some candidate materials which are hypothesised to be able to stand up to temperatures somewhere near what's required, but to my knowledge (which admittedly might be out of date) nothing's actually known to be suitable.
The reason I don't think the neutron absorption issue is such a problem here or on Polywell is because with a smaller reactor, replacing the vessel when it stops working is a far less terrifying prospect, even if you have to do so every few months. And even this is far less insane than some of the proposals for how you might do commercial laser fusion. That's just bananas.
Beyond that, you actually want some fast neutrons from the reaction to give you a tritium source.
What part of the reactor degrades so quickly? Can't it be replaced continuously? Why isn't the shielding done with some non-degradable matter, like water or some oil?
As an example of the problem, anything made of metal will become brittle. For why this might be a problem, take a look at what's in the middle of the ITER toroid: you've got a stack of magnetic coils, which have to be physically braced against a colossal magnetic repulsion by a great big pre-stressed metal core.
I'm sure someone at ITER has done the maths and figured out how long that core can last under operation before it becomes too brittle to keep the coils together, but I wouldn't be at all surprised if that was one of the reasons why ITER isn't designed for long-term power generation.
If the shielding is made of matter, then the nuclei of the atoms in that matter will absorb neutrons and become radioactive. Clearly the solution is to make it out of the many materials which are not composed of matter.
There are still some serious basic physics issues to be worked out.
They dismiss the concerns of the scientific community. Why shouldn't they? They're getting rich off of the ignorance of generals and venture capitalists.
I'm not sure why this article is focusing on things like whether the reactor can fit on a truck, where you get deuterium, and how many coal power plants it can replace - instead of the actual question which is how they managed to produce a stable exothermal fusion reaction.
As far as I can tell from reading various articles (including the Aviation Week article linked elsewhere in the comments), they haven't. The expectation is that they will have a prototype in five years. For that reason, I wouldn't get too excited about this.
Interesting when you compare to the recent dynomak paper announcement[1]. The pointer to 'superconducting magnets' doesn't get a lot of ink though. I went by Fry's the other day and they were out of them :-) I wondered about them because to date such things usually are sitting in a cryogenic bath (think MRI machine) and not next to a million degree hot plasma. Even in the LHC there is a lot of space between the beam and the ring magnets. Dr McGuire in the article suggests -- “We should be able to go to 100% or beyond,” which is quite the challenge from the thermal management perspective.
It is however another great example that there is money going into lots of different fusion ideas. And that can only be a good thing as far as I am concerned.
This appears to be further development of the novel nuclear reactor approach described by Charles Chase at Solve in 2013 -- https://www.youtube.com/watch?v=JAsRFVbcyUY. The video provides a basic overview of fusion reactor designs and their breakthrough.
This bothers me immensely. Clearly, neither the author nor the editor for a "Scientific American" article (for pete's sake, science is in the name!) know the difference between nuclear fission and nuclear fusion.
This article is the cognitive equivalent of parrots squawking, because they don't even understand why the news actually is news.
People calling this a "typo" are giving too much credit. It could be a mistake, but the whole point of having an editor is to catch typos and mistakes! And it's a simple, short article!
Just in case someone skipped out on the relevant day of middle school science, it should be 'fission'.
The difference is that fission is taking heavy elements, breaking them apart and using the released energy. Radioactivity, Thorium, Uranium, Plutonium, all the yucky stuff. Research has been going on for decades into making these reactors safer, and with breeder reactors and modern conventional designs that appears to have been achieved. Nevertheless, they appear on their way out anyway.
Fusion fuses together light isotopes and uses the energy thus released - they basically do what the sun does. And are clean. For various definitions of clean.
And if you're wondering how they are the complete opposite yet both work, it all pivots around iron. Copying from Wikipedia on iron:
> Its abundance in rocky planets like Earth is due to its abundant production by fusion in high-mass stars, where the production of nickel-56 (which decays to the most common isotope of iron) is the last nuclear fusion reaction that is exothermic.
And yes, that means that everything in this universe will one gigayear end up right at the pivot between fission and fusion, ever onwards oscillating further towards it. Our universe is ever tending tiwards irony. A pivot that we're probably going to see humanity go through too, but in a different way. Hopefully sooner rather than later.
25 years ago my nuke professor used to scoff at some of the claims of the fusion researchers. The problem is the high energy neutrons flying out of the reactor will neutron-activate every material within the vicinity. He thought the radioactivity and nuclear waste of a fusion reactor could be worse than a fission reactor. Also he thought that fusion researchers were vastly underestimating the problem of neutron embrittlement of the reactor structures and components. This is a very difficult engineering and material science problem that would have to be solved even if they did get the fusion process to work.
With D-T fusion you would have more activation of the reactor materials, because D-T produces such high-energy neutrons. What you wouldn't have is transuranics, which make up the bulk of our nuclear waste (and all of the really long-lived stuff), or fission products (the most radioactive stuff, like the cesium and strontium we heard about after Fukushima).
But D-T is only the easiest form of fusion. Next up is D-D, which has much lower-energy neutrons. Helion is working on D-D combined with D-He3, producing only 6% of its energy as neutrons. And several outfits are hoping to manage proton-boron fusion, producing very little neutron radiation.
Correct me if I am wrong, but each of these "steps" is a research project in their own right.
The AviationWeekly article mentioned D-T fusion for the Lockheed prototype and includes a diagram with the caption "blanket absorbs neutrons to breed fuel and transfer heat to turbines". This "blanket" will be tons of material that would be activated during operation and would have to be disposed of at EOL. Also, modern materials include many trace elements within the main molecular lattice such as cobalt, chromium, etc in steel and in some ways might be more difficult to process than used fuel rods.
I worked in the nuclear power industry decades ago and I don't recall the how the energy of fusion neutrons vs fission neutrons compared but I thought that in general fusion neutrons were significantly higher. Most power fission reactors also have neutron moderators which help to reduce the activation and embrittlement problems. Nevertheless, core components in fission reactors are already experiencing neutron embrittlement and has been a concern.
I'm not trying to be negative on fusion power but these overly optimistic reports have to be read with a critical eye.
Oh absolutely. There are people trying to jump right into the more advanced reactions, but Lockheed is just aiming for D-T right now. My point is just that D-T could end up being a transitional technology. Once any form of net-positive fusion is available, I'm thinking research will ramp up a lot.
I haven't seen any good quantitative comparisons of D-T waste to fission, now you've got me curious.
I don't know about the waste being worse, since none of it will be transuranic. All short-lived activation of a few hundred years at most, you could just switch it off and mothball it really.
Totally agreed about the neutron embrittlement, I think that (IFMIF aside) this issue has just been brushed aside as a materials engineering 'detail' to be dealt with as part of commercialisation in a few decades when it might actually make the whole concept of using fusion for energy impractical.
I think my prof's main point was that the volume of waste could be problematic. If a fusion reactor had a 50-60 year life it could activate a lot of material. The volume of fission reactor waste is small enough to be stored on site (so far) for decades and reprocessing can reduce that dramatically.
Based on the image of the machine, this is a magnetic mirror with neutral beam injection. Mirrors were some of the first plasma confinement devices. An issue they have is that they lose charged particles out the ends in a way that depends on the ratio of perpendicular to parallel velocity and the magnetic field strength. It may be that they think they can use the neutral beam injectors to inject the fuel in such a way that it's well confined in the machine...
Never mind, another linked article says that the injectors are only used for ignition.
"The team acknowledges that the project is in its earliest stages, and many key challenges remain before a viable prototype can be built."
No doubt that Skunkworks is world class... but claiming a "breakthrough in fusion energy" before a prototype has even been built is pretty bold of them.
> Initial work demonstrated the feasibility of building a 100-megawatt reactor measuring seven feet by 10 feet, which could fit on the back of a large truck, and is about 10 times smaller than current reactors, McGuire said.
So that would power 50k to 100k typical houses in the US... not bad!
Compact is good, because until you can fuse helium-3, the reactor is producing neutrons, which will transmute the reactor and its shielding into other, often radioactive elements. So the entire thing will have to be regularly replaced and disposed of (which we can do safely, but too many people believe otherwise).
I do not see how compact matters much here. As far as I understand, the basic reaction used is the same, so that compact design will produce the same number of neutrons per Watt produced as a large one.
Wouldn't the effect of its smaller mass be that the container will have to be replaced more often, more or less in the ratio of the masses of the machines?
We really don't know the practical consequences of this systematic transmutation (for all we know, neutron liberating fusion reactors will never be economic). It's entirely possible the device will have to be replaced more often, I'm just pointing out the less mass in it, the less that has to be disposed of when that happens.
"Until now, the majority of fusion reactor systems have used a plasma control device called a tokamak, invented in the 1950s by physicists in the Soviet Union. The tokamak uses a magnetic field to hold the plasma in the shape of a torus, or ring, and maintains the reaction by inducing a current inside the plasma itself with a second set of electromagnets. The challenge with this approach is that the resulting energy generated is almost the same as the amount required to maintain the self-sustaining fusion reaction."
I have the link to xkcd 678 "Researcher Translation" bookmarked for those occasions. Quoting the appropriate row here:
If a researcher says a cool new technology should be
available to consumers in... -> what they mean is...
[...]
ten years -> "we haven't finished inventing it yet,
but when we do, it'll be awesome."
I'm used to hearing that nuclear fusion is going to become mainstream "in 30 years"; I've heard it for ~25 years. If it's 10 years now, some progress has been made.
The mainstream magnetic confinement community has been very cautious about overhyping lately. Unfortunately, the over zealousness of groups like this and NIF saps credibility from them anyway.
"The early reactors will be designed to generate around 100 MW and fit into transportable units measuring 23 X 43 ft."[0]
These reactors will be similar to the Nimitz-class aircraft carriers and potentially only require refueling every 25 years through a process known as ROH.[1]
100MW capacity in the size of an international shipping container? The implications of this are massive if this technology can be brought to scale, and that is the key term - SCALE.
The cost of solar is plummeting and by the time fusion technology can produce 10% of our energy demand the cost of solar will be heading to $1/Watt, battery storage will be competitive and that is hard to beat even if the footprint is only a fraction of a solar farm.
I'd love to know how they're planning on disposing of heat in the magnets themselves - most of the available high-current superconductors prefer to stay close to liquid helium temperatures, which is a challenge when you've set them next to a ten megakelvin plasma that's emitting a 100MW neutron flux...
Crazy. Vernor Vinge has an excellent short story called "Bookworm, Run!" [0] that, among other things, discusses the effects of cheap, clean, compact power being distributed around the world. In particular, it describes a wide-spread economic depression. Kind of interesting to think about, and definitely worth reading if you're into sci-fi.
The ".NET Rocks!" podcast did three GeekOut shows this year on nuclear fusion, which will probably make you only more skeptical of fusion research claims.
As someone who still remembers the excitement and the disappointment due to Pons and Fleischmann (I was a teenager at the time), I'm going to wait for independent verification. But I can't deny I'm a bit excited.
This looks like a real thermal engineering challenge in one respect. The superconductive magnet coils are exposed to the neutron flux that transfers fusion reaction energy to the absorptive thermal blanket. I don't know offhand the neutron cross-sections of likely superconductor materials at whatever neutron energy spectrum this reactor will produce, but I suspect energy absorption by the magnet structure won't be small. I wonder how they plan to keep the magnets cold. Never mind the other effects on materials of high-flux neutron absorption.
I guess that's somewhat game-changing. This, however, would be much more game-changing (if we can get confirmation once and for all whether it's real or not):
Aneutronic fusion would be lighter-weight, but it's good to see another concept we can learn something new from. There are two aneutronic fusion projects to look at. Polywell has become a Navy project last I heard and focus fusion (DPF) is working on an all-tungsten electrode, after which we might see the very first experiment without electrode contamination from arcing in the contacts vaporizing metal.
It's dangerous to read the market's mind, but my guess is that there isn't enough information for anyone to believe that this is anything more than a PR puff piece.
As much as I want to believe it I can't find any evidence myself, either. At this point I'm pretty much at the "show me the over-unity reactor" phase. There's so many research paths to fusion right now that are all "promising", but until one of them actually builds something that works in the real world I'm not personally interested in hearing any more vague promises.
By all means fund them and keep working on them! I'm just not interested in the PR pieces any more. Give me a report about how it's working.
Lockheed has a market beta of 0.7 -- So it's correlated with the general market fairly strongly. On aggregate, if the market increases or decreases by 1%, you'd expect Lockheed to follow the market by 0.7%.
Today most of the major indices are down ~1%, Lockheed is down 0.4%, so you could attribute that 0.3% deviation from the expected number as reactor news. 0.3% of Lockheed's market cap represents about $170M today.
It's obviously not this straightforward, but if I were a shitty journalist, I could make the case that this is actually a pretty good result since commercialization will likely be a decade away, it will take a ton of resources and investment to get there, and there's a high chance of failure.
A shitty DCF with a ramp to $500M/year in R&D, 75% margins on sales, and a $10B/year business in perpetuity comes out to $170M NPV with a ~31% discount rate --- Not too unrealistic.
The general consumer sentiment and state of the economy are much more important even for a company such as Lockheed (slow economy > less profits > less taxes > less DoD spending) than unproven (as of now) claims about yet another fusion reactor.
I was wondering the same thing. People have claimed to have working fusion reactors just in a few years if they only could have some more funding for so long that anyone who claims to offer a production capable fusion reactor loses their credibility completely until they actually produce one.
Skunkworks have as an organization an amazing engineering track record of implementing ground breaking technologies. I wonder what their current status is. Anyone have an inside scoop whether their game is still as sharp?
The article is completely wrong about US Navy ships having fusion reactors. They have fission reactors, not fusion. I wonder if they are even reporting the breakthrough right since they clearly don't know the difference. For all we know the breakthrough may be smaller fission reactors too, which isn't a big deal at all.
> U.S. submarines and aircraft carriers run on nuclear power, but they have large fission reactors on board that have to be replaced on a regular cycle.
The article certainly does, even if Lockheed does not.
"U.S. submarines and aircraft carriers run on nuclear power, but they have large fusion reactors on board that have to be replaced on a regular cycle."
US naval vessels have fission reactors, not fusion. I'm also pretty sure that although they would refuel a reactor, that rather than replace the reactor they'll likely replace the ship.
While Wiktionary has "A device which uses atomic energy to produce heat" as one definition, other dictionaries all include the ability to regulate/control/sustain a nuclear reaction. I'm inclined to agree with them.
Well, we all understand that a nuclear warhead is technically a reactor but not what we mean in practice when we use that word. The typo in the article was just a bit unfortunate.
It's only technically a reactor if you accept Wiktionary's definition of what a reactor is, instead of any of the "real dictionaries". I'm of a mind that setting off an uncontrolled nuclear reaction doesn't make something a reactor.
So, they've come up with a way to make a fusor that produces more energy than it consumes? Also, I'd be interested in knowing what kind of scram mechanism they develop. If the superconductors were to fail, the expansion of the plasma would be catastrophic, right?
It certainly wouldn't produce a runaway fusion reaction, if that's what you mean. A hot plasma would dissipate pretty quickly once confinement fails, so the only energy would be that in the plasma itself. Might be bad for whoever is in the room, but probably not the county.
Right, I meant catastrophic for the reactor. Definitely not worried about blowing up the country. Probably shouldn't have typed that phrase. NSA is probably all over me now.
I don't know much about fusion. It seems that the breakthrough they're talking about is that reactors are ~10x smaller. Why is this a big deal? Square footage is plentiful. I thought the problems are safety and how much energy it could produce.
One big difference is the smaller the device, the quicker and cheaper it is to iterate. If it takes 15 years and $X billion to build and test your device, then progress gets measured on a per-lifetime instead of per-year basis. If your device can be built in a year and for $X millions instead, the testing and debugging can be done much faster. For a software dev comparison, think waterfall versus agile.
If it's 10x smaller it is available for portable applications. Like boats/planes/space ships. It would also presumably be easier to air drop in developing regions to bypass building a giant energy grid (similar to cell phone deployment).
I think it's less about the size in square feet than the size in dollars (including installation, maintenance, and waste disposal). The pool of people willing to buy a $100M device is small. The pool of people willing to buy a $10M device - even if it's less efficient - is much larger. That makes it a potential revenue source, instead of an eternal revenue sink. Much as fusion doesn't become technically useful until energy output exceeds energy input, it doesn't become economically useful until revenue (for its maker) exceeds cost.
That's a 20 year old 1GW combined cycle gas plant, in a building roughly 50mx150m. Anything they can do to bring fusion plants smaller than ITER is going to help.
"Partners in industry and goverment". Translation: 10 years to product (but hey, prototype in 5) so please give us lots of dough. It's the technology of the future and always has been.
On a tangent, is there any fundamental reason that reactors are always built to drive turbines rather thermocouples - do they simply not scale up to the amount of heat a typical reactor puts out, or what?
Steam turbine plus a conventional generator is vastly more efficient than thermocouples - 30-40% for steam versus <5% for thermocouples.
I suspect they are also much, much cheaper when you are talking about powers in the hundreds-of-megawatts range. I don't have specific data at hand to back that though. I never heard of any grid-level power generation being done with thermocouples.
That is in line with general impression. I just find it really weird that after all the high-tech nuclear stuff is working the next stage is an old-fashioned water boiler like on a steam engine of hundreds of years ago. (Well, obviously these turbines are not old-fashioned or simple boilers, but you know what I mean.) It just baffles me that we don't have a way of efficiently generating electrical current directly from particle radiation, eg through pressure fluctuations in a magnetic field, instead of through heat transfer.
The reason we'll need turbines for the first generation of fusion reactors is that most of their energy is released as neutrons. Some more advanced fuels release most of their energy as fast-moving charged particles, which would let us generate electricity more directly.
Can we assume that their reactor isn't energy positive? Because if it were, I would imagine that they would be announcing so--rather than this nebulous "breakthrough."
From the aviationweek.com [0] article, it seems it is a concept, and they don't even have a prototype. They are trying to get some fundings to build the PoC. What makes the announcement a bit strange is that they have very concrete claims "it will fit in a truck" without much substance.
IMHO the best thing is how they pitch this as a power source for carriers and military ships, that are mostly used to fight wars for oil. Well played, Lockheed.
"Ultra-dense deuterium is an isotope of Hydrogen" (1) ultra-dense?, (2) and tritium which is denser (but hardly ultra-dense) and also an isotope of hydrogen.
This article provides a lot more engineering information and other background and is well worth a thorough read. Thanks to flexie for finding and sharing the link.
Hyperloop case doesn't have 50 years of track record of being "just few years from now", and as far as I remember, the design was more-less feasible if only someone would get around to building it. It didn't have such hard problems to be solved as fusion still has.
> Hyperloop case doesn't have 50 years of track record of being "just few years from now"
There have been steady incremental advancements in the field. I think your knee jerk reaction is coming from "cold fusion" which does have the problems you are talking about. Two very different fields.
The main issue with fusion is that it can't be weaponized and therefore doesn't have a nice military grant behind it. It lacks a Manhattan Project. It's probably always been "a few years from now" under the assumption of adequate funding.
The events following this announcement will probably be a good time to form a concrete opinion on fusion. It's being given a fair chance, so lets first see if it can prove itself.
This is promising stuff. Most of the other reactors have been Tokamak reactors - which are better suited to research and not practical applications, so we could be seeing some interesting results here.
It's true that there were people in the early 70s who said fusion was thirty years away. However, they conditioned that on a certain level of funding. For the funding they got, the same people said it would never happen.
Thanks for the graph, and @DennisP for saying the same in written words. I recall seeing that graph once on HN, but for some reason I didn't pay attention to it back then.
I don't believe this is the case. I'm pretty sure there have been "hard" limits so far on what can be achieved. I'm not a physicist, not even close but as I understand it two issues remain. One is that sustaining the fusion reaction has been problematic. I believe the longest sustained reactions have been less than one second. Two is that currently we have to put more energy into creating and sustaining the reaction than it yields. These two things make this categorically different than a challenge like building the hyperloop which as far as I know didn't have any unsolved science or engineering problems.
Again, I could be wrong on my physics but as I understand it, fusion power is still a question of "is it even possible" whereas the hyperloop was more of a question about socioeconomic will.
One of the problems with creating longer-running fusion reactions is that if they do it, in order for the reactor to not wildly overheat almost instantly, they need a massive cooling system to carry the generated heat away. At that point, you almost might as well hook up a steam turbine loop and generator and put the power on the grid.
There's lots of other problems too - I don't think they have a well-tested solution for adding fresh fuel and disposing of the fused products on an ongoing basis.
JT-60 in Japan has done about half a minute, actually. There is less of an issue with sustaining reactions (since there has been steady progress over the years) than with coming up with materials that would stand up under a commercial fusion reactor's duty cycle.
I'm happy if that is true, but guys: the first thing you think of is putting a potentially massive explosive on the back of a truck? Driven by humans? What could go wrong...
True, but we currently have gallons and gallons of highly flammable liquids hidden behind the cheapest #8 steel possible and something literally called a bumper, all exposed to whatever rust and rocks the nation's roads can throw at it. It's all about the level of risk.
"McGuire said the company had several patents pending for the work and was looking for partners in academia, industry and among government laboratories to advance the work."
I'm guessing this means that they will try and maximize profit rather than maximize cheap and clean energy for the entire world. That is a bit disappointing if true.
"I'm guessing this means that they will try and maximize profit rather than maximize cheap and clean energy for the entire world. That is a bit disappointing if true."
I don't understand what you expect? You want them to give it away for free? After paying very intelligent, expensive engineers decades worth of salaries to create it? You want them to create a fund where people can donate their hard-earned money for this noble goal? I'm sure you could give them a call with that idea, or you could create your own fund, even.
Or you could badger your "government" to fund such a project. Seeing as government is a very good analogy for a bunch of people giving their collective earnings for society-level goals. Let me know how that goes.
Our main reason for war right now is scarce energy.
Cheap clean electricity means no-one needs to care about the Middle East for starters — most of the fighting there is superpower proxy fighting — e.g. Assad would be gone if not backed by Russia and China, so no Islamic State. No Oil, no Iraq war x2. No oil, no Hugo Chavez for that matter.
I would only be cautiously optimistic : even if our energy problems are solved, the construction of reactors, for example the superconductors, might require some rare materials. The grab for energy could become a grab for minerals. It will probably involved other regions of the world though and change the whole dynamic.
On a similar vein, I wonder what are the strategical consequences of such an advance. Assuming it works as described in the article, do you allow the technology to be exported ?
Because a whole fleet of fusion air carriers, battleships, submarines and bombers versus a conventional army has plenty of implications in term of autonomy, reach, etc.
But on the other hand, there is a such demand for energy everywhere that it would really hard to morally ban all the civilians applications.
Energy use of the US (2011): 25,484 TWh
Power needed: 2,900 GW = 25,484 TWh / 365 / 24 h * 1000
Number of 100 MW CFRs: 29,000
Civilian use will happen. The benefits are just much to great. There will be regulation and oversight for them. But you won't need one in every truck. It's overkill. As you can see from the above calculation 29 thousand CFRs could cover all the US energy needs. So there will be hundreds of thousands worldwide. It will be hard to keep all of them under control
But this would basically solve all of humanities energy problems and decrease CO2 production, and destruction of the environment from mining immensely.
Having large amounts of energy available enables new weapon systems to become feasible: high powered lasers, coil guns and rail guns. They can be added to any air, land, or sea vehicle that's above the size of a small truck.
Ships are pretty large anyway and aren't as restricted as land or air vehicles when carrying big machinery. Aircraft carriers won't change so much. You can build them a little smaller and their defensive weapons might improve. Nuclear submarines otoh could be built as small as modern diesel powered subs like the Dolphin class.
You could build a drone with an extremely long loitering time. If it uses a laser or rail gun, it will also have lots of ammunition. Instead of carrying a couple of hellfire rockets and having to refuel after several hours it could stay in an area for months.
Then the dilemma becomes: Does the USA share this with other countries? Or do we keep our clean, plentiful power for ourselves, become energy independent, have clean skies, and keep (exploit?) this technological advantage over the rest of the developed world for the next 20-30 years?
You can't have clean skies if everyone else is polluting. That is what makes pollution such a hard problem to solve. Even if USA cuts its pollution to zero, China alone can make up the difference.
But yeah, having access to this technology for everyone would be a serious game changer.
What dilemma? Its a no brainer we use it for free and have the rest of the world use it at a $profit$, while getting to enjoy that very same clean(er) air. But as history has shown it is probably too good to be true. Fusion that is.
Edit: We are all riding the same spaceship... Its a serious flaw in thinking 'us vs them' when we are beginning to experiene some of the results in climate change.
Problem with fusion research like this is that the closer you get self sustainment or energy generation, the harder it gets and problems pile up. This project looks like many other similar projects that have gone bust. They start by solving the easiest problems first, get some funding and hit the wall.
The main problem with any reactor design is how to handle the 14 MeV neutrons produced by the fusion reaction (no mention in the article). They tend to damage the reactor and make it economically unfeasible. At this point being able to create fusion reaction is not the main challenge. It's the sustainment and economics of limiting the damage. If they really have solved all the problems and demonstrate economically sound fusion in 5-10 years, they will be handed Nobel price in physics for sure.