Slashdot is powered by your submissions, so send in your scoop

 


Forgot your password?
Close
typodupeerror
×
Power Japan

World's Biggest Experimental Nuclear Fusion Reactor Launched In Japan (theguardian.com) 119

Posted by BeauHD from the size-matters dept.
The world's biggest operational experimental nuclear fusion center has been inaugurated in Naka, Japan. The Guardian reports: The goal of the JT-60SA reactor is to investigate the feasibility of fusion as a safe, large-scale and carbon-free source of net energy -- with more energy generated than is put into producing it. The six-storey-high machine, in a hangar in Naka, north of Tokyo, comprises a doughnut-shaped "tokamak" vessel set to contain swirling plasma heated up to 200mC (360mF). It is a joint project between the European Union and Japan, and is the forerunner for its big brother in France, the under-construction International Thermonuclear Experimental Reactor (ITER).

Sam Davis, the deputy project leader for the JT-60SA, said the device would "bring us closer to fusion energy." "It's the result of a collaboration between more than 500 scientists and engineers and more than 70 companies throughout Europe and Japan," Davis said at Friday's inauguration. The EU energy commissioner, Kadri Simson, said the JT-60SA was "the most advanced tokamak in the world," and called the start of operations "a milestone for fusion history." "Fusion has the potential to become a key component for energy mix in the second half of this century," Simson added.
This discussion has been archived. No new comments can be posted.

World's Biggest Experimental Nuclear Fusion Reactor Launched In Japan More

World's Biggest Experimental Nuclear Fusion Reactor Launched In Japan

Comments Filter:

  • Fusion godzilla comeing soon!

  • In 20 to 40 years, guaranteed!

    • Thing take 3 or 4 times longer than expected sometimes. So what?

      • Yeah, and sometimes it takes forever. So nothing.

        • I'll bet you would have given up on rocketry when the first few rockets failed.

          • And I bet you'd have put your money into alchemy even as Rutherford published the results of the atomic structure.

            • Who published something showing fusion is impossible? In fact it's always been the opposite, except for a few approaches such as IEC.

              • What do you mean, "fusion is impossible"? Fusion is possible. What isn't possible is making it work for the declared purpose - to quote:

                to show the feasibility of fusion as a safe, large-scale and carbon-free source of net energy -- with more energy generated than is put into producing it

                Tokamak won't work for that purpose, its feasibility has been shot down many times already.

            • I've never seen any of you anti-fusion people cite any theory showing it to be impossible. The mantra of your side has always been "fusion is impossible because you said it would be done in 20 years (nevermind we cut funding)". I haven't even seen a crackpot theory as to why it's impossible. I mean, we have crackpot theories for everything else. Not even the Flat Earth Society or Hollow Sun folks have proclaimed fusion impossible.

            • And I bet you'd have put your money into alchemy even as Rutherford published the results of the atomic structure.

              The correct analogy is this: yes we have the technology to turn base metals into gold (proton bombardment and so on). The cost of doing so is 100X the value of the gold produced.

              "Fusion this decade" has been the mantra since the 70s. We have barely reached wall-plug breakeven.

              • Yeah, but then we'll hear that we're only years away from cheap transmutation - and we'll be shown the Indian breeder reactor program as an example.

                And in fusion we're very, very far from wall-plug break-even, we haven't even reached power in to power out breakeven in a sustained reaction.

          • So, that would have been about 1300 (in China), and 1700 (in the West)? (Rocketry was a minor but significant part of military arsenals by the mid-1800s, for battlefield illumination, signalling etc).

            Oh, are you talking about liquid-fuelled rocketry? Ah well, that was a considerably fiddlier technology. But the experience with solid-fuelled rocketry through the 1700s to 1900s had proved the underlying physics, and the problems were merely ones of pumping equipment and nozzle materials, both worked on one (

            • That is how it is for fusion except unlike rocketry it has progressed a lot over 50 years instead of 700. Stop acting like it is zero progress. We fairly confidently know the conditions required for net energy fusion. If ITER was build in 1984 as proposed we’d have it today. Even the version being built today is heavily scaled back.

              • If ITER was build in 1984 as proposed we’d have it today.

                ITER was scaled back not because of lack of funding, but because of lack of justification for the funding, as it became obvious that even at scale it ain't going to achieve much of what it promised.

                And what ITER has promised isn't even close to achieving "fusion power" as in "too cheap to meter", however you define the latter.

      • The thing is, cold fusion has been due in 10 years for about half a century now.

        • 30-odd years, not 50-odd years. But you're under-inflating the subject by it's own internal standards of promises versus delivery.

          I'm sure you meant to say that "cold fusion has been due in 10 years for about half a millennium now". Such an easy 10-character typo.

          • I somehow don't think that they were planning to get cold fusion somewhere in the 1500s. Back then I think they didn't even have a fucking clue what fusion would even be like.

            • Of course they did. All problems will be solved by god. Not having enough power to heat the house in winter is a problem that god will solve. Until god provides a better solution, throw another cow pat on the fire. ("Peasent" for richer people, not cow pats. Because richer people are closer to god than poorer.)

      • Re:Power to cheap to meter! (Score:5, Interesting)

        by hey! ( 33014 ) on Saturday December 02, 2023 @09:41AM (#64048937) Homepage Journal

        Yes, things take longer than expected, but if you're making progress then finish line, while further away than expected, should look closer. If it never looks closer chances are you aren't making any real progress at all.

        The problem with all major fusion projects is that they use the Deuterium-Tritium fuel cycle. This has the advantage of having the lowest energy needed to achieve a fusion reaction that will generate more energy than put in. It has the *huge* disadvantage that nearly all the energy it releases is in the form of neutrons that are useless -- we can't turn them into electricity to run the reactor, they're just lost.

        If I understand correctly, converting neutrons into useful energy is one of the main research goals of ITER. If a workable scheme for generating electricity comes out of that, then a practical fusion power generator becomes a matter of engineering and economics. Until then, marginal increases in Q (fusion gain factor) don't put us as much closer to reality as they look. If you want to even *think* about creating a working power plant and you're throwing away 80% of your energy as neutrons, you don't need Q>1, you need Q>5. In the past 25 years the record for Q has gone from 0.67 to 1.54, which is an impressive 230% gain. But assuming that progress is linear (very optimistic), reaching Q>5 at this rate will take another 99 years.

        • Well, you should likely also all the system level losses. As at least most quoted yields are at reaction level, not system level.

          That is from the laser beam to total evergy out. But lasers far from 100% efficient and then the energy needs to be converted to electricity and the turbines are again not 100%.

          • Re: (Score:2)

            by hey! ( 33014 )

            Sure. To be a practical power plant, you need to exeed engineering breakeven which means you take more electricity out than you put in, as opposed to physics breakeven, which is a benchmark with essentially no practical significance.

    • Re:Power to cheap to meter! (Score:4, Informative)

      by backslashdot ( 95548 ) on Saturday December 02, 2023 @03:24AM (#64048503)

      And by the way, that number is always based on funding levels. Fusion energy funding has been nearly zero since the late 1980s it's a miracle anything is up and running.

      • You forgot to link that picture, where the fusion power is perpetually short of 200 billion euros, without justification. It is always helpful.

        • Is your goal to block fusion funding and prevent it from happening?

        • Hmm... Could you link to it? I have no idea of what you're talking about.

          The closest I can think of is that it takes $X millions/year just to tread water, knowledge wise. It's like how we no longer know how to make Roman concrete, battleship sized rifles, etc...

          This is to maintain a set of people familiar with fusion, equipment, operations, experiments, etc... You're constantly having to train new ones in order to replace retiring ones.

          So if your funding is very close to $X, you're just treading water.

          • You're not "simplifying it", you're talking out of your ass, and you have no valid point to make.

            • Thank you for validating my post by failing to actually make an argument against it. I assume it is correct because rather than attacking my point, statements, or anything, you felt the need to attack me.

              "talking out of your ass" - Ad Hominem [wikipedia.org]
              "no valid point to make" - Appeal to the Stone [wikipedia.org]

              • How could I possibly validate something that doesn't even exist, like the "point" that you don't have :)))

                Spending more on a cause already lost isn't going to make it more viable, it will just make you poorer.

                • Ah, still insisting on validating me, I see?

                  Tell me, what makes these not points:
                  1. There's a difference between "information" and "knowledge". Information is basically stored data. Knowledge is data ready for application in a human head. It takes work to convert the prior into the latter.
                  2. Knowledge expires. People retire, die, move out of the field, and without continued practice, training new people in the knowledge, the knowledge will be lost. You need to keep training new people, in other words

                  • You lack knowledge, expired or other, in the domain, and you spew bullshit.

                    Let me ask you one question, is fission power a marvel of nature, or a technology?

                    • Again with the validation! I mean, do you expect me to do something other than call you out for again resorting to personal attacks rather than addressing my statements? Do you need some assistance in learning how to argue/debate stuff properly? I mean there's lists of debate tactics and fallacies to avoid out there.

                      Let's see:
                      1. Target the argument. Avoid personal attacks.
                      2. Use logic, reason, and evidence. Starting with evidence, note how I sometimes post citations, links to topics. These posts are

                    • Didn't ask you about "fission", dimwit, asked you specifically about fission power. Is it a marvel of nature, or human a technology? :)

                    • False Dichotomy [dictionary.com].

                      I already gave you my answer. Limiting me to two choices means that you intend both to be a trap. And unlike Ackbar, I'm not falling for it.

                      At this point, I'm going to suggest that you pay more attention in class, and if you're no longer in class, you might want to return. Your comprehension is apparently lacking, so you might want to study english more, as well as taking a class in logic, debate, philosophy, and such.

                    • In other words, you don't know, but you have an opinion. :)

                      No, it ain't a "false dichotomy". Let me give you a bit of an education beyond Star Wars trivia:

                      https://www.sciencedirect.com/... [sciencedirect.com]

                      See, it (in this case a BWR) is really a marvel of nature.

                      Now, what does that mean to us?

                    • Ah! You finally actually cite something, progress! Still, I never said I knew everything. Also, yes, it's very much a false dichotomy. A real hint is that you make it an "either or" answer which isn't a true/false. I'm allowed to have a different belief/opinion than the two you give. Hell, they aren't even properly mutually exclusive.

                      And yes, I've known about the natural fission reactors since like grade school. After all, they covered the big one presumably at the center of the earth back then. I th

                    • Are they really "power" reactors if they effectively aren't doing anything but produce heat

                      What do you think is the output of any reactor, rainbow fairy fart? Oh, the ignorant idiot you.

                      Back on track, now that we know that a nuclear fission reactor is a marvel of nature, what does this tell us?

                    • You haven't answered my question yet. Why should I answer yours?

                      That said, you know what, no, it isn't a marvel of nature, because it doesn't provoke any sense of wonder or astonishment in me. Just mild curiosity. The universe is marvelous, but a random pile of fissile material big enough to hit criticality is just to be expected given the formation parameters of the Earth.

                      Just go ahead and tell me. My thought processes obviously work a lot different than yours. I'm not actually an ignorant idiot like

                    • it isn't a marvel of nature, because it doesn't provoke any sense of wonder or astonishment in me.

                      I'm not surprised to read this.

                      Like I said, you're too ignorant an idiot to have a proper perspective. You don't understand the processes involved, and you don't appreciate what improbable marvel of nature gave us fission energy. That is why you cannot evaluate correctly the (lack of) potential of "fusion power".

                      And yeah, your thought process is defective, as in, completely based on bullshit and on avoidance of fact and principle :)

                      Don't worry, you're not alone :)

                    • Given that you're the one avoiding fact and principle, I'd stop looking in the mirror before throwing out accusations of ignorance and idiocy. It's your thought processes that are defective, not mine.

                      At this point, given that you are equating fission and fusion, when they are actually quite different, that you refuse to actually cite any facts, provide any reasoning, and have to fall back on personal attacks, accusations of ignorance, which should be really easy to fix by providing SOMETHING other than per

                    • Okay, lay out on me why you believe this. Should be simple, right?

                      Yes, it is fairly simple if the one who needs to be taught knows the basic principles, which you do not. Same problem as explaining why earth isn't flat to flatearthers, they lack the capacity, but they have the fire in their bellies for an argument. I've given up, as it doesn't pay :)

                      But you can try to answer this simple question yourself: "Why is it so that fission power technology has a natural analogue on Earth, and fusion doesn't?".

                      Enough to get you started on the crawling out of your Dunning-Kruger st

                    • I'll even give you a concrete hint, look carefully at the energies of the particles that participate in the respective reactions. In particular, think which part of the fission reaction is conceptually most like (or unlike) the fusion in the various links of the pp chain.

                      Nature is, indeed, a marvel, too bad its miracles are seldom appreciated by the vulgar.

                    • Yes, it is fairly simple if the one who needs to be taught knows the basic principles, which you do not.

                      You're assuming again. Given your stringent insistence on not explaining anything, not even attempting, the easy conclusion is that you can't, and are stuck talking out of your ass.

                      I've given up, as it doesn't pay :)

                      You've spent more effort calling me names than it would have taken to at least make a single attempt.

                      But you can try to answer this simple question yourself: "Why is it so that fission power technology has a natural analogue on Earth, and fusion doesn't?".

                      Ah! Here we go. My response would be that it's because the natural conditions are different. To see fusion power though, we only need to look towards the sun. There's a lot more fusion power going on than fission in the unive

                    • Is it possible for you to just tell me?

                      You should learn to listen. To yourself for a start :)))

                      To see fusion power though, we only need to look towards the sun.

                      Precisely :) So, what's the lower bound on the size of a fusion reactor of that type?

                    • Precisely :) So, what's the lower bound on the size of a fusion reactor of that type?

                      Not power positive, but teenagers have done it in their garage. [wikipedia.org]

                      You should learn to listen. To yourself for a start :)))

                      That isn't telling me what you're trying to get at.

                      And oddly enough, I do. I'm not perfect, of course.

                      But we seem to have completely lost the plot.

                      Again, why do you think that my argument that there needs to be a certain level of spending in a field to maintain proficiency in that field, much less progress in the field, either doesn't exist or is bullshit?

                      Where does talking about whether or not economical fusion power plants are even viable,

                    • Not power positive

                      So, why bother bringing it up?

                      that there needs to be a certain level of spending in a field to maintain proficiency in that field, much less progress in the field, either doesn't exist or is bullshit?

                      because amount of spending is irrelevant here. the "fusion reactors" are not failing because of lack of funding, funding is lacking because of failure to demonstrate feasibility of fusion reactors.

                      The lower bound on a fission reactor is what happened in that African desert. The lower bound on a fusion reactor is a brown dwarf. We're short 15 or so Jupiters to build one.

                    • I brought it up because you asked for a lower bound. You didn't specify that it had to be power positive.

                      We hit power positive [llnl.gov] with 3MJ produced from 2MJ input. Which, in powerplant terms, is relatively tiny. Given that the 3MJ was generated as heat, while we need to transform that into electricity to do things like continue powering the system.

                      The lower bound on a fusion reaction in nature might be a brown dwarf, but with humans involved, it's a garage.

                      You want useful for generating electricity, well, w

                    • The lower bound on a fusion reaction in nature might be a brown dwarf, but with humans involved, it's a garage.

                      You're confused again. We're not discussing fusion reactions, we're discussing fusion power. The lower bound is for a reactor that can produce continuous output. At this moment, still a brown dwarf.

                      If there was enough funding that we could get better test equipment built expeditiously, have more people working on it, etc... We'd be much further along.

                      What does that mean, "if there was 'enough' funding"? How much is enough? Based on what justification? What "testing equipment"? The first fission reactor (go look it up) was built by 30 people from "bricks and timber" at then cost less than $200k or so, which would be a bit less than 4 million USD today.

                      Fusion p

      • Brian May (yes, that Brian May) on Conan O'Brien's podcast noted that the US spends more on dog grooming than fusion research.

  • I think they meant... (Score:5, Informative)

    by rzzzwilson ( 748598 ) on Saturday December 02, 2023 @02:38AM (#64048471)
    200MC. It doesn't take much to "heat up" something to 200 milli degrees C.

    • Re: (Score:2)

      by at10u8 ( 179705 )
      really they meant 200 MK because nobody cares about the difference of 273
      • An error of about 1 part in 10,000 - which is pretty poor for physics or chemistry. But it's still better than the 1 part in 1 which is the precision level acceptable in the dismal and social sciences (economics, sociology), while the liberal arts still don't have a measurement concept.

        OK, OK : 1 part in 4000. Which is still better than dismal arts and liberal sciences.

  • 200mC? Damn that's cold (Score:5, Insightful)

    by Rosco P. Coltrane ( 209368 ) on Saturday December 02, 2023 @02:57AM (#64048481)

    Oh yeah... Science reporting from The Guardian.

    • It is a cold fusion reactor.

    • Re:200mC? Damn that's cold (Score:4, Insightful)

      by greytree ( 7124971 ) on Saturday December 02, 2023 @05:51AM (#64048643)
      Stop oppressing the author with these irrelevant facts - I bet you're a white, abled male and probably protestant. You pig.
    • It would take ice a long time - metaphorically "forever", but not literally "forever" - to melt at that temperature. Precisely how long would depend on the mass of the ice, it's starting temperature, the size of your heat source (at +0.2 degC ; irrelevant if it is externally maintained at that temperature) and the thermal conductivity between heat source and heat sink. But it would feel like forever, compared to applying an oxy-acetylene torch to an icecube.

  • An old joke about tokamak... (Score:3, Funny)

    by LordHighExecutioner ( 4245243 ) on Saturday December 02, 2023 @02:59AM (#64048483)
    ...A physics student from middle East is walking along the seashore. He is deeply depressed, because the tokamak to which he is working on for his Ph.D. does not ignite.
    While walking, he accidentally trips into something half buried in the sand. He digs the thing out, and a strange brass lamp comes out. He rubs the lamp to clean it, and surprise! A genius comes out of the lamp.

    The genius stretches out a bit, since he has been buried there for more than one thousand years, and then says: "Thank you for freeing me! As every genius in a lamp, who frees me can ask me wishes, and I will fulfill them. But, since I am quite out of exercise, since I have been reclused so long in the lamp, you have just one wish available for you."

    The student thinks a moment, then ask the genius: "Dear genius, please bring peace and friendship in the Middle East region!"

    And the genius: "Come on, dear. I am a genius, but I am not practicing since so long! Please choose a wish easier to fulfil."

    The student: "OK, then make my tokamak work".

    The genius sits for a moment thinking and then: "Well, do you have a map of Middle East ?"

      • A "genie", not genius.

        I found it funny regardless, and I originally thought the use of "genius" than "genie" was going to be part of the punchline, and perhaps in a way it was.

        Now I'll get annoyingly pedantic...

        The word "genius" can carry the meaning of a spirit, an incorporeal being, that guards some person or place. The word can also mean a person of considerable influence. At least those are two definitions I found in an electronic dictionary. Presumably there's room to interpret the word as holding a bit of both meanings,

  • Fusion is A-OK. But solar+battery = still better. (Score:5, Insightful)

    by Eunomion ( 8640039 ) on Saturday December 02, 2023 @03:25AM (#64048505)
    The Sun is a fusion reactor, costs nothing ever, shines on the just and the unjust alike, and cannot be stopped by any choice of man. All you have to do is take what it gives and store it somewhere.

    • Small problem: the Sun gives photons, and the photons don't stop, they travel at the speed of light. So "all you have to do" becomes a rather complicated series of tasks of making something that can convert "what the Sun gives" into something that you can actually use.

      And then it is no longer as simple as you imagine it.

      • It's not like you don't have to do the same tasks with a fusion reactor, in addition to brain-smashingly complicated other stuff.

        • The semiconductor industry that makes "solar + battery" available can appear to someone as somehow less complicated than fusion only for one reason - ignorance.

          • The semiconductor industry already operates at scale, and iterates as a matter of routine. Fusion reactors depend on mind-numbingly bespoke systems at every level that take on order of a decade to iterate.
            • I think that you'll find that new generations of semiconductor manufacture (in both size of feature, or area-of-chip manufactured per plant per year) also take Order-of(a decade) to iterate. But the next two generations are already in process, and the physics (and chemistry) for the two after that are already in the labs. Whereas the "lab" stage for tokamaks (or other fusion plants) are what are is currently being built at Caderache and in Japan. And probably in China too, but with less hooplah.
              • The semiconductor industry is a lot bigger than just chip manufacturing, and doesn't have to wait for chip cycles to innovate simpler products, but still benefits heavily from investments in chipmaking. I would be hard pressed to think of fusion having a similar relationship with downstream products.

      • Well, ok, but that problem was addressed a century ago with photovoltaic cells. Here's a wiki link for you to read:

        https://en.m.wikipedia.org/wik... [wikipedia.org]

        So, not a problem. Just logistics we've been working on for a century.

      • Well, let's see.
        The USA currently uses about 4,000 terawatt-hours of electricity a year (4x10^12 Wh). (https://www.statista.com/statistics/201794/us-electricity-consumption-since-1975/). Let's call it 5x10^12 for ease of calculations.
        Let's use an average of 5 hours of solar production a day (https://unboundsolar.com/solar-information/sun-hours-us-map), assuming that we build solar installations across the southern US and distribute power northwards via the power grid.
        That means we need about (5*10^12 / 5)

        • the 5 hours a day that Solar is producing needs to provide electricity for 24 hours

          Oh, you can manage that. Most industry shuts down (approximately) 06:00 to 18:00. Mandatory bedtime from 21:00 to 06:00 (because the power goes off, and the Black-out Patrol can execute anyone who is operating a light). That'll cut down the storage requirements.

          Having a baseload power system (for the unavoidably 24*7 industries) would reduce that a lot, though the Black-out Wardens might object to having the power of life an

        • Now, there are some missing dollars in this analysis.

          You are missing vast majority of dollars in your analysis.

          For example, there's no money for storage - the 5 hours a day that Solar is producing needs to provide electricity for 24 hours. But even doubling the cost doesn't make for a untenable situation, assuming we don't do something stupid like trying to create a lithium-ion battery farm large enough for storage. They're great for load-levelling, but not at the scale we're discussing. Pumped hydro or similar bulk energy storage solutions would be far more reasonable.

          Last time I looked into this amortized cost of 24 hours worth of storage is the equivalent of the sum total of all current day energy related expenditures. The entire infrastructure of existing buffer storage, extraction, generation, transmission... all of it costs the same as what would be required to store 24 hours of energy. 24 hours is comically insufficient if you are seriously considering fully solar solution.

          The optimal solution can only be

    • It mostly has the unbeatable advantage that it works.

      • Yup. Zero maintenance cost and 100% reliability on the "reactor" portion of a solar plant. Very little maintenance cost and extremely high reliability on the harvesting side.

    • Re: (Score:3)

      by e3m4n ( 947977 )
      Theres plenty of areas where solar is not viable. Northern Canada and Alaska for starters. Most likely Norway as well. Aside from bouts of prolonged darkness, even during extended long light, its solar index is still low due to the angle of incident with our atmosphere. The further you are from the equator, the less effective solar becomes in a very non-linear fashion. Its best to tap all potential energy sources. If the sun is heating the oceans 24x7 then by all means tap that resource as well. If the sun
      • Remote areas of Canada, Alaska, Norway etc. actually do find solar advantageous (along with other things) due to otherwise high energy costs. Big cities tend to do fine with hydro, but that's tough to scale and subject to climate-related disruption as water courses change or diminish.

        Thermal power sources are also fine but, again, have high input costs and are much harder to scale than solar panels. The energy of needs of the world would easily be met by a very tiny fraction of land that isn't even use

    • All you have to do is take what it gives and store it somewhere.

      The former is can be done but the latter is prohibitively expensive.

      However, there are enough NIMBYs to keep large solar and wind farms from ever materializing. We need to pursue all options.

    • > and cannot be stopped by any choice of man

      How does one acquire panels and batteries without permission?

      I have both but I'm well aware that they wear out and a supply chain is needed for parts.

      I lost an MPPT controller to a lightning strike and needed to replace it despite the breaker giving its life for the rest of the system.

      Passive solar and thermal mass batteries don't run a modern society.

      • I was talking about the Sun itself, not the gathering equipment. But yes, solar can run a modern society quite easily. That fact is ironically why adoption has been slow, because the cheapness of the solution makes it unattractive to energy industry investors accustomed to holding entire regions hostage in perpetuity and demanding extortionist rates from customers. Once the world goes solar, they will not be able to put the genie back in the bottle: The energy industry will never have as much political p
    • Look, our ability to harness solar rays on earths surface and turn them into electricity, and also to store electricity for future usage in batteries, are amazing technologies that we need to be thankful for. They have a billion+1 practical applications. The intense energy needs of a complete modern society is just one of those rare few that doesn’t work. We use too much energy, and energy use is directly correlated to advancement of civilization and quality of life. The people who spout this nonsense

  • Better nonGuardian link an editor could have found (Score:3)

    by greytree ( 7124971 ) on Saturday December 02, 2023 @05:56AM (#64048647)
    Link to the site of THE ACTUAL PEOPLE DOING THIS.

    Slashdot Editors: EDIT or get a more suitable job.

    https://www.jt60sa.org/wp/operation/

  • Old (Score:5, Informative)

    by Meneth ( 872868 ) on Saturday December 02, 2023 @07:02AM (#64048677)
    This is hardly brand new. It's an upgrade started in 2013, to the JT-60 [wikipedia.org] reactor originally built in 1985.

  • Fusion power works, if it is big enough. (Score:5, Interesting)

    by MacMann ( 7518492 ) on Saturday December 02, 2023 @04:29PM (#64049773)

    It's getting close to 20 years now since the presentation was made but I can recall watching a YouTube video about the Polywell Fusor. https://en.wikipedia.org/wiki/... [wikipedia.org]

    There was a lot of information packed in the talk by Robert Bussard about the Polywell Fusor but one thing that stuck out to me was the calculation on power in to power out based on the size of the fusor. I thought it odd that there was no mention on what this gave as a minimum size for the fusor to reach breakeven power. I did a bit of math to give me some idea on the size and came up with a number that indicated the containment vessel would be about the width of a Nimitz class aircraft carrier.

    The reason I thought to compare the size of the fusor to an aircraft carrier was because this research in the Polywell was funded by the US Navy under their nuclear propulsion research. I'm no nuclear engineer but I had enough math education in high school to figure out the minimum size of a fusion reactor that would reach breakeven.

    The problem then becomes that breakeven is not enough to make a working power plant. It would have to make many times more power out than it takes to run it to be viable. Thankfully for those involved the rate at which power output grows to the size is exponential, meaning it should take only a very small increase in size of the reactor beyond breakeven to get useful amounts of power. But that is still a very large engineering problem to make a fusion reactor large enough for net power output. A tokamak may be very large but it is not all that tall, while a Polywell Fusor would have to be spherical, which makes constructing a tokamak trivial by comparison.

    From what little I know of nuclear fusion the science of a fusion reactor that can produce net power output is well understood. The engineering might actually be relatively trivial with available materials and construction techniques. The problem is finding someone willing to put up the money on building a fusion reactor large enough to reach net power output. I suspect another obstacle is producing enough power to get the thing started. I remember going to see some kind of farm tractor museum where on an old tractor was a starter engine. Not a "starter motor" since that implies electric start, it was a "starter engine". This was a big diesel engine, at least as I recall, that had a smaller diesel engine to get it going. The operator would have to crank start this little engine, wait for it to build up sufficient speed, then engage it with the large engine. I can just imagine a huge fusion reactor with a small fleet of fission reactors around it to provide the power required to get the thing started, in many ways like that old tractor. A small engine can be pull started or kick started. A bit bigger and they use electric motors or compressed air. When they reach a certain size then the problem of starting them up involves a small engine to start the big engine, and because the problem is making a "fusion engine" small enough there will be a need for some other technology to step into the role of "starter".

    That gets to another point about fusion as an energy source, we know how to make practical fission reactors so there's not likely to be much interest in fusion. Most any opposition to nuclear fusion would likely be shared with nuclear fission because both have the word "nuclear" in them, and "nukular" is bad. Find a way to get beyond this opposition to all things "nukular" and there's little point to taking that path into nuclear fusion.

  • Just for the fun of it, I looked up some of the earliest stories about fusion on Slashdot. Take this one from 2002: U.S. to Rejoin the ITER Fusion Project [slashdot.org]. It reports, "The USA left the ITER consortinum in 1999 when it bulked at the 10 Billion dollar price tag." Here we are 24 years later: ITER still hasn't been completed. The official estimate of the total construction cost is $22 billion [scientificamerican.com], but that estimate is considered totally unrealistic. In 2018 the US DOE estimated the actual construction cost at

  • a doughnut-shaped "tokamak" vessel set to contain swirling plasma heated up to 200mC (360mF)

    Please check your units basics. m stands for milli, that is on thousandth. M stands for mega, that is, one million.

    I am confident no fusion will be achieved at 200 milli-celsius, and that we should read 200MC instead of 200mC.

Slashdot Top Deals

Pause for storage relocation.

Close