[HN Gopher] The quest for fusion energy
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The quest for fusion energy
Author : mellosouls
Score : 61 points
Date : 2022-05-28 15:00 UTC (8 hours ago)
(HTM) web link (inference-review.com)
(TXT) w3m dump (inference-review.com)
| FunnyBadger wrote:
| Fusion energy has been "coming in 5 years" ever since 1960. Just
| like Gallium Arsenide will replace Silicon. Except neither has
| happened and the reasons are physics!!
| alasdair_ wrote:
| The reason for literally everything is "physics".
| credit_guy wrote:
| > It is likely unachievable anytime in the next half a century.
|
| It is very important for this message to get through. Fusion is
| not "just around the corner".
|
| By the way, the energy generated by fusion is higher than that
| generated by fission, but not by a huge amount. Only by a factor
| of 4.
|
| The energy density of Deuterium+Tritium is 337 TJ/kg. The energy
| density of Uranium is 81 TJ/kg. For comparison, the energy
| density of methane is 56 MJ/kg or more than 1 million times lower
| than that of Uranium.
| 77pt77 wrote:
| And it was 50 years away 50 years ago.
|
| It's always the same.
|
| Reminds me of a well known electric car CEO that says self-
| driving cars are 3 years away and has been saying that for 10
| years.
| headmelted wrote:
| I mean I sort of see why you've been downvoted (this is off-
| topic and adds nothing to the discussion), but you're also
| not wrong.
|
| Extraordinary claims require extraordinary evidence, which is
| a lesson that we learned a million different hard ways and
| which has been almost completely forgotten.
| willis936 wrote:
| 1 kg of deuterium is a lot friendlier to be around and less
| alarming to find anywhere on the planet than 1 kg of U-235. 1
| kg of tritium is a hazard, but it's also more than the global
| annual production of tritium and any DT reactor would be
| engineered to have low tritium inventories and a controllable
| breed rate.
| credit_guy wrote:
| U-235 has a half life of 700 million years. When it decays,
| it releases alpha radiation (Helium neclei), which is not
| that dangerous. As long as you don't ingest or inhale it,
| U-235 is harmless. If you do ingest or inhale it, it will
| probably harm you more because it is a heavy metal than
| because it is radioactive.
| willis936 wrote:
| Do you know how many people you can threaten and actually
| kill with 1 kg of U-235?
| DennisP wrote:
| > there are daunting engineering challenges involved in
| stabilizing a torus where the inboard legs of the magnet coils
| are subjected to extraordinarily high electromechanical stresses
| and overturning moments.
|
| True, but MIT (and by extension CFS) has more experience with
| this than anyone. Their Alcator C-Mod had the strongest magnetic
| field of any tokamak. I got a tour of it once, and a grad student
| showed us a metal tie rod, about a meter long. He said they'd
| calculated that two of them could have held down the Space
| Shuttle when it was trying to launch. To keep the reactor from
| flying apart, they needed 38 of them.
|
| > In any case, improving cost-effectiveness is surely a
| distraction for MCF research when there have been no advances in
| Q
|
| Except smaller, cheaper reactors mean you can iterate experiments
| a lot faster.
| manholio wrote:
| > two of them could have held down the Space Shuttle when it
| was trying to launch. To keep the reactor from flying apart,
| they needed 38
|
| And all that for a reactor that was unable to break even in
| energy terms, let alone ignite and break even economically.
|
| It perfectly illustrates the folly of magnetic confinement: to
| hold the plasma you need fields so strong and equipment so
| massive and expensive that the capital expenses get out of
| control, fully negating any advantage fusion might have over
| fission. We already know how to make capital intensive energy -
| the fueling costs are negligible for a fission reactor, yet
| those largely failed in the market. An even more expensive and
| capital intensive solution is dead in the water for economic
| reasons regardless of any theoretical merits.
| willis936 wrote:
| Mechanical strain has never been anywhere near a limiting
| factor on the engineering of MCF machines.
| peterburkimsher wrote:
| Instead of a ring-shaped tokamak with magnetic confinement, the
| thought came: why not a 1-dimensional Mobius strip?
|
| After a brief bit of web searching, it turns out that the
| design exists, and it's called a Stellarator:
|
| https://en.wikipedia.org/wiki/Stellarator
|
| And if you're ever thinking about building one at home, just
| try not to cause an accident. What's more dangerous than
| playing with fire? Playing with smoke detectors.
| kkfx wrote:
| Curious that they do not mention the far more developed fusion
| reactor in France, but anyway while I prize research in general I
| always reiterate that we can and MUST dream, but at a society
| scale, not company, not lab, we need thing that work for sure
| NOW.
|
| Witch means that's hyper-right funding a PUBLIC research on
| fusion energy even if it demand *centuries* before showing usable
| results, BUT we have an energy production issue now and we need
| to sort it out quickly for real, not in a potential future...
| ceeplusplus wrote:
| Moonshots need a focused direction of R&D, not design by
| committee. ITER is the definition of design by committee. VC
| backed funding is a much better model for this kind of idea
| where the tech is _almost_ there but need capital intensive
| build outs to validate it.
| Bouncingsoul1 wrote:
| Really? the actual moonshot was exactly this, design by
| committee, no VC backed funding...
| pfdietz wrote:
| Apollo was also a dead end. It resulted in a system that
| was so expensive not even the government wanted to keep
| using it. It's taken a private approach to get launch costs
| down to the point that returning the moon may be practical.
| BuyMyBitcoins wrote:
| If we had stuck with the Saturn V and conducted one moon
| landing per year, it would have been far cheaper than the
| Space Shuttle program.
|
| I applaud the private sector's results, but the Apollo
| program was a national triumph and should in no way be
| considered a dead end technologically. It was the
| politicians that failed the program, not the other way
| around.
| moogly wrote:
| ITER was mentioned several times in the article. I am guessing
| that's what you meant by "far more developed fusion reactor in
| France", even though "far more developed" could be argued since
| it's still under heavy construction and has not started
| operation, and thus has produced no results as of yet. D-T
| operations are scheduled for 2035, and it will most certainly
| miss that target. Plus, it's still an experimental reactor and
| meant to be a proof of concept. DEMO, a commercial reactor,
| would then be designed and constructed using the learnings of
| ITER (if it turns out feasible, which is unproven at this
| point).
| ncmncm wrote:
| If you want to spend for energy production, fusion is, by far,
| a worse choice than most alternatives.
|
| Spend on building out existing solar and wind. Spend on
| building out transmission lines. Spend on improved solar, e.g
| longer-lived perovskites. Spend on a wider variety of storage
| media. Spend on cheaper electric-driven ammonia synthesis.
| perihelions wrote:
| How does tokamak fusion interpolate between pure D-D and 50/50
| D-T? Like, responsive to footnote cite [30], if tritium recovery
| falls short, could you run a sustainable D-rich D+T mixture,
| where D+D helps provide more neutrons for breeding tritium? Or
| does it only make sense to jump *all the way* to pure D+D (like
| the author argues in OP). What exists in the intermediate zone?
| ncmncm wrote:
| None of those will ever produce economically meaningful
| results.
|
| So it is only a matter of what can appear to produce _any_
| apparent results, enough to unlock further grant funding.
| idatum wrote:
| "The incoming fusion neutrons sustain the temperature of the
| circulating liquid metal, whose heat would be extracted to drive
| a turbine."
|
| I assume this means a steam turbine (heat engine). With the
| losses inherent in that process, I assume the idea is we'll have
| a "limitless" source of heat anyway?
|
| Or is heat transfer inherently better with this fusion design?
| gameswithgo wrote:
| 77pt77 wrote:
| Same way fission works.
|
| All these methods are really sophisticated ways to heat stuff
| and rotate a turbine.
| bryanlarsen wrote:
| If fusion relies on a steam turbine, it's going to be
| economically infeasible. Natural gas power is cheaper than
| either coal and fission power because they both rely on big,
| heavy, expensive, inefficient steam turbines.
|
| And solar power and wind is cheaper than natural gas, even with
| batteries.
| perihelions wrote:
| - _" Natural gas power is cheaper than either coal and
| fission power because they both rely on big, heavy,
| expensive, inefficient steam turbines."_
|
| Most natural gas power plants in the USA use steam turbines.
| The most common setup is a two-stage "combined cycle": first,
| an internal-combustion gas turbine, whose waste heat powers a
| lower temperature steam turbine.
|
| https://en.wikipedia.org/wiki/Combined_cycle_power_plant
|
| https://www.eia.gov/todayinenergy/detail.php?id=39012 (~90%
| of natural gas kWh)
| bryanlarsen wrote:
| The gas turbine is primary in combined cycle. There's a
| reason they don't use only a steam turbine like coal and
| fission do.
| photochemsyn wrote:
| This is really the most comprehensive write-up of nuclear fusion
| R & D I've ever come across. However, the conclusions aren't that
| hopeful for the notion of nuclear fusion as a useful energy
| source anytime soon. On the technological scale, it seems closer
| to the likelihood of terraforming Venus, rather than the much
| more feasible notion of colonizing Mars.
|
| Basically it seems like the ICF method is more effective and as
| an experimental system, uses much less tritium, but using it to
| drive a power production system (converting heat to electric
| power) is much more difficult than with the MCF system, if even
| possible. The MCF system on the other hand seems nowhere near
| reaching breakeven.
| ncmncm wrote:
| ICF is even less practical than MCF, and MCF is not.
|
| We will with certainty _not_ get commercially competitive, or
| even usable, energy from fusion. Any money spent on that
| prospect is badly misdirected. Support fusion research to
| direct money to support plasma physicists, or to keep certain
| exotic-tech military contractors afloat, or to drive
| superconducting electromagnetics.
| gruturo wrote:
| ICF is pretty much bomb research masquerading as civilian
| fusion research. Always has been.
|
| Any money spent on it is not at all badly misdirected, it's
| rather accurately directed, you could say.
| collaborative wrote:
| > There are two broad approaches toward achieving terrestrial
| fusion. In magnetic confinement fusion (MCF), magnetic fields are
| used to confine the hot fusion fuel in the form of a fully
| ionized gas or plasma that persists for seconds or longer. In
| inertial confinement fusion (ICF), laser or particle beams are
| used to compress and heat a tiny capsule of fusion fuel to
| generate a micro-explosion of a nanosecond duration.
|
| I thought there were now 2 more: projectile method via gas gun
| and piston containment of molten lead
| notorandit wrote:
| Fear the e-cat scam!
| ThrowawayTestr wrote:
| Check out General Fusion for a company that's working on an
| actually tenable fusion reactor.
| pfdietz wrote:
| It requires considerable optimism to think GF's approach is
| "tenable". I don't believe it is.
| ncmncm wrote:
| And even that wouldn't be competitive with existing wind and
| solar tech.
| AddingValue wrote:
| 1.3MegaJoule output from 250KiloJoule on target (laser) energy
| 2021 August
|
| NIF
|
| https://www.youtube.com/watch?v=zWeQICvl42k
| leephillips wrote:
| In order to direct that much laser energy on target, they had
| to expend far more energy than the claimed output. Never
| forget, the laser system is far less than 10% efficient.
| [deleted]
| jonplackett wrote:
| It's amazing just how many problems scaled up fusion would solve.
|
| War in iraq? Why bother.
|
| War in Ukraine? Just stop giving Russia fossil fuel money
|
| Climate change? Let's just not.
|
| Why aren't we just spending _all_ the money on this?
| simonh wrote:
| There's no guarantee it's a solvable problem. With the
| Manhattan Project we knew it was feasible and how to do it, all
| we needed was engineering.
|
| With fusion we don't know how to do it. There are many, many
| ideas we could pursue, and they are being pursued, but we have
| no idea if any of them will actually work. It's quite possible
| none of them will, or that solving it might take enabling
| technology we haven't even thought of developing yet.
|
| For context we have already spent several Manhattan Projects
| worth of fund on fusion research, in inflation adjusted terms.
| ncmncm wrote:
| We have certainty they will not be solved. Anyway, not to
| anywhere in sight of commercial competitiveness.
|
| Fusion can never even come close to competing with fission,
| and fission is not today competitive. It gets less so every
| year.
| anarazel wrote:
| You made 10+ comments along those lines, just for this
| article. How about providing at least some justification,
| rather than making absolutist statements?
| pfdietz wrote:
| DT fusion has inherently lousy volumetric power density.
| ITER's thermal power density, for example, is 400x worse
| than a commercial pressurized water reactor's primary
| reactor vessel. ARC's is 40x worse. Now couple that with
| those cores being far more complex than a fission core,
| and the difficulty of maintenance (they will be too
| activated for hands on maintenance.)
|
| IMO, the only fusion company that has a real chance is
| Helion. Most of the breathless hype runs into generic
| showstopping issues like the ones above. If someone
| presents a new fusion concept, ask them about their power
| density, and how much complexity there is in that core.
| 77pt77 wrote:
| Abundant clean energy for humans would be a social disaster of
| cataclysmic consequences.
| rapsey wrote:
| Because it is still very much up in the air if fusion is cost
| effective. If the price to build a plant is astronomical it can
| not make enough energy to pay for itself.
|
| A better question is why we are not investing in solar, wind
| and hydrogen more.
| ncmncm wrote:
| The best information available says fusion as pursued will
| never be _anywhere close_ to competitive even with fission
| (which is not today economically competitive), never mind
| with photovoltaic solar panels (which are).
|
| Fusion research is cool beans, but not for any plausible
| practical reason.
|
| Given that, all the work on making it happen at big scale is
| a wholly wasted. The companies issued billion-dollar
| contracts to build parts of it do not see those contracts as
| wasteful, and hope we won't.
| grej wrote:
| Those have a role in the energy landscape to be sure, but
| they don't offer the benefits of fusion because they don't
| have the same power density.
| ncmncm wrote:
| Fusion does not "offer benefits" of any energetic or
| economic kind. It is interesting in the same ways that
| microkelvin cryogenic and gigapascal hyperpressure are,
| exercising extreme physics.
|
| Fusion does not offer energy density even approaching
| commercial fission.
| deepspace wrote:
| Yes, but they have the incredible advantage that they
| produce large amounts of energy economically _today_ ,
| whereas, as the article states, it is not yet clear whether
| fusion will _ever_ be able to produce significant energy,
| let alone economically.
| p1mrx wrote:
| Wind and solar only produce energy when the weather is
| cooperating, and it's difficult to predict how climate
| change will impact future availability. Hydrogen might be
| economical someday, but currently it's rather difficult
| to generate, store, and transport.
| ncmncm wrote:
| There is _always_ wind and solar somewhere. It need only
| be transmitted or stored to be used in other places and
| times.
|
| Both of those are cheap. People advocating nukes wish
| they were not.
| mcronce wrote:
| Hand-waving away the transmission/storage required to
| make intermittent energy sources "reliable" does not
| magically make them trivial, or even solved, problems.
|
| I don't really care whether or not nukes are cheap when
| they're the only reliable low-carbon energy source we
| have, and when they're the safest energy source we have.
| Some things are more fundamentally important than
| economics.
| pfdietz wrote:
| We can look at simulations using actual historical
| weather data and actual cost estimates to determine how
| much it would cost to deal with intermittency of
| wind/solar using storage. The result is something that
| looks cheaper than fission (or cheap than fusion is
| likely to achieve.)
|
| https://model.energy/
| ncmncm wrote:
| Yet, people deciding where to spend their own money are
| spending it on solar. Nukes are always built with money
| coerced from other people.
| stormbrew wrote:
| > A better question is why we are not investing in solar,
| wind and hydrogen more.
|
| This always comes up in discussions about fusion but do you
| really think we aren't? Solar didn't get where it is now from
| a lack of funding. A lot of money and time and effort has
| gone into it, just not mostly into one boondoggle project
| everyone can point to.
|
| I would really like to hear numbers to back up the idea that
| investment into these (esp. solar and wind) is "small" in
| total because I'd easily bet on it being several orders of
| magnitude more invested in than fusion.
| ncmncm wrote:
| It is small in exactly the sense that it must become much
| bigger if we hope to fend off climatic catastrophe.
| hotpotamus wrote:
| Show me your budget and I'll show you your priorities. What
| pays better, fusion researcher or CRUD app writer?
| willis936 wrote:
| Public fusion researcher pays pittance. Private fusion
| researcher pays fair.
|
| More butts than seats on that fast-moving ride.
| anovikov wrote:
| Because the whole field is an easy to debunk bullshit which is
| worthless in practice. If today somebody came up with a working
| thermonuclear reactor with a positive energy output, nothing at
| all will change in energy markets, because it basically means
| you are getting a complex and expensive steam boiler that runs
| on effectively free fuel. But even electricity made from coal
| has only 20% of the coal price in it, meaning, there won't be a
| dramatic improvement in energy cost if fossil fuels were free.
|
| Renewable energy today provides very cheap energy inputs and no
| improvement in this field can yield any dramatic difference.
| And everything that comes further downstream has to be paid,
| anyway.
|
| Research in it is still a good thing though because a lot of
| other discoveries and technology improvements are done on the
| way, bringing benefit even if result itself is useless (like
| with the moon landing).
| mrtksn wrote:
| Probably because it's not a solved problem that simply needs
| money to scale up?
|
| If you think about it, you can't simply give money to JS
| developers to do fusion research instead of making HTML buttons
| for internal use.
|
| Those who can work in the field already do but so far there's
| nothing to show in terms of practical solutions. They even
| receive fair bit of criticism for misrepresenting the outcomes
| of their work to get more funding. Every now and then a startup
| or something will come up to claim that they thought of
| something novel that will solve all of the problems and how the
| people who work in expensive government funded programs are
| amateurs with no creativity, then disappear in the valley of
| vaporware dreams.
|
| Humanity is deeply invested in it, it's just that it's really
| hard.
|
| Oh, BTW, We already have a reliable and extremely powerful
| nuclear fusion reactor in the sky. We can actually pour
| enormous amount of our resources into harnessing it and succeed
| but it is considered a divisive topic.
| ncmncm wrote:
| " _a divisive topic_ "
|
| On HN, anyway. The wider world is all in on solar, except
| where it might compete with oil extraction subsidy.
| peteradio wrote:
| > War in iraq? Why bother.
|
| I guess we take as a given we were there for cynical oil based
| reasons?
|
| > War in Ukraine? Just stop giving Russia fossil fuel money
|
| The oil/gas doesn't cease to have value under sanctions, at
| worst it can all be consumed internally to drive their war
| machine. Climate change isn't driving Russia to desire Ukraine,
| it just does.
|
| > Climate change? Let's just not.
|
| The government we are cynical of now has the power to control
| climate and our cynicism vanishes?
| chrisco255 wrote:
| If only all practical problems could be solved with money.
| We're more awash with money than ever but competence is
| carefully rationed.
| andi999 wrote:
| It will produce a lot of nuclear waste though (neutrons
| activating and damaging the hull)
| ncmncm wrote:
| Anyway, short-lived reactors.
| baryphonic wrote:
| I sort of feel this way, but the problem seems sufficiently
| complex that the solution is "path dependent," much in the way
| chip process generations are (we couldn't have jumped straight
| from a 100nm process to the present 5nm processes just by
| spending all of our money on it). Just spewing out money would
| likely lead to lots of fraud, and the outcome would be similar
| to the current funding regime.
| walkhour wrote:
| Politicians aren't here to offer to solution or to improve the
| state of the country, they are here to maintain themselves in
| power and reward their friends. Their friends don't like
| fusion, and supporting fusion would make it less likely for
| them get reelected.
|
| Until the winds change and supporting fusion would make it more
| likely for them to get reelected, they will be making up all
| sort of stuff of why we should waste money in less proven and
| more unreliable, and possibly dirtier sources of energy.
| ncmncm wrote:
| Politicians do better when they can ride on things delivering
| popularly valued results. Fusion won't. Solar and wind are,
| already.
| spurgu wrote:
| We could also look at simpler ways of living. Simply not using
| that much energy. Politically that's a suicide move (to
| promote), but it can happen on a grassroots level. Housing
| policy for example would need to change. People should be able
| to build simple houses using natural methods without having to
| comply with complex building codes.
|
| Upgrading living standards for poor people is (or should/would
| be) easy: https://www.youtube.com/watch?v=VtbjQ51NvDg
|
| A bigger problem is making people less career-driven and settle
| for a simpler life, small-scale farming, permaculture etc.
| Photosynthesis is free and abundant!
|
| But we're locked into this mental trap of constant growth. We
| just assume that the only way should be up - more energy, more
| people, more stuff...
| willis936 wrote:
| This author wrings their hands a lot and says "gosh that
| engineering sounds hard" and then stops there. Look at the stated
| timelines of ongoing projects and watch the news. Armchair
| engineers ought not be confident.
| leephillips wrote:
| "This author wrings [his] hands a lot and says "gosh that
| engineering sounds hard" and then stops there."
|
| But that itself is a useful contribution to the discussion
| around the fantasy of fusion energy, when the national labs are
| constantly seeding the media with deceptive press releases.
|
| https://progressive.org/op-eds/let-cut-our-losses-on-fusion-...
| willis936 wrote:
| It isn't useful because it says "the devils in the details
| but I don't know any of the details. Isn't that scary?" Are
| you going to make decisions based on that? Armchair
| speculation costs nothing if you're wrong.
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