Twenty Seconds At 100 Megakelvins

The Korea Superconducting Tokamak Advanced Research (KSTAR) magnetic fusion reactor claimed a new record last month — containing hydrogen plasma at 100 megakelvins for 20 seconds. For reference, the core temperature of the Earth’s Sun is a mere 15 megakelvins, although to be fair, it has been in operation quite a bit longer than 20 seconds.

South Korea is a member of the International Thermonuclear Experimental Reactor (ITER) team, a worldwide project researching the science and engineering of nuclear fusion. One of their contributions to the effort is the KSTAR facility, located in the city of Daejeon in the middle of the country (about 150 km south of Seoul).

It is a tokamak-style fusion research reactor using superconducting magnets to generate a magnetic flux density of 3.5 teslas and a plasma current of 2 megaamperes. These conditions are used to confine and maintain the plasma in what’s called the high-confinement mode, the conditions currently favored for fusion reactor designs. Since it went into operation in 2008, it has been creating increasingly longer and hotter “pulses” of plasma.

For all the impressive numbers, the toroidal reactor itself is not that huge. Its major diameter is only 3.6 meters with a minor diameter of 1 meter. What makes the facility so large is all the supporting equipment. Check out the video below — we really like the techniques they use in this virtual tour to highlight key components of the installation.

50 thoughts on “Twenty Seconds At 100 Megakelvins

    1. The Wendelstein 7-X already does 100 seconds. The reactor is now under upgrades to the cooling system for true steady state operation in 2022. It was supposed to be done in 2021 but the work got delayed because of the virus.

    2. Here’s a list of other fusion milestones:

      I forget how long JET plasmas were/are. A good few seconds and likely approaching 20 sometimes. Most of the time I was on shift, disruptions were being studied. So it would be several seconds of calm, then the plasma would wobble madly before going sort of whoomph/bang/slap into a wall. Then 20 minutes of furious diagnostic checking to see if it’s still OK before doing it all again. As a result, I more think of the plasma as a really angry solar flare that is particularly miffed about being kept in a magnetic bottle than a star :O)

      Oh, and KSTAR managed 72 s at a little cooler 70,000,000 K. Rather feel it has the potential to go for longer at the higher temp too. The mentioned spec for it’s design is 300 s – but at what temperature?

      Can’t write “Fusion is cool” as that’s just wrong. So here we go – Fusion is spiffing.

      1. i think jet’s claim to fame is its q factor. q=1 is scientific breakeven. you need something around q=10 for engineering breakeven. a couple more orders of magnitude on top of that and you can use aneutronic fuels.

        1. forgot to mention that jet i think has a q=0.67 or whereabouts. they are going for the q record again in 2021. its the closes thing we have to a working reactor until iter fires up. all these reactors breaking records is good because that means progress is creeping forward.

          1. JT-60 in Japan reached a theoretical Q = 1.25 if it had been fueled with D-T instead of D-D in 1998. They didn’t have the facilities to handle tritium, and the reactor would have overheated.

            In 2006 they achieved a 28.6 second plasma, and from 2013 they were under upgrades to JT-60SA which is coming online now. Last news was from September when they were starting to pump the vacuum.

  1. Congratulations to NFRI / KSTAR. 100,000,000 °K is impressive temperature-wise. For comparison the average temperature of the solar corona and solar wind is about 1,000,000–2,000,000 °K; however, in the hottest regions it is 8,000,000–20,000,000.[1] 100,000,000 °K for 20 seconds is impressive time-wise in our overall pursuit of fusion energy here on Earth. Other facilities as well as KSTAR itself have sustained plasma fields for longer [2], but to my knowledge not at 100,000,000 °K.


    2. Artificial Sun “KSTAR”

      1. Heh. Yeah it’s been “5 years away” for 40 years, and I don’t know if there’s a way to tell if we’ve even crested “Mount Stupid” on the D-K curve of sustained fusion knowledge.

    1. How much energy do they burn to create, contain, and maintain the plasma, once started? And how much energy have they recovered, in those few seconds? The goal is to generate electricity, but haven’t seen anything on that end, just the fireball portion.

  2. There is no indication of any possibility that FUSION reaction can be controlled. Trying to develop this energy is very much like creating a virus as biological weapon and tell everyone the weapon is under controlled. I will not recommend anyone pursuing this venture as this is a venture of playing GOD.

        1. And never mind those 10-or-so centuries where the Christians were in charge and the only technological advances we made were new and improved methods of torturing heretics to death…

          1. This is a huge mischaracterization. Scientific advances would have been far slower without the church’s support of early universities. Many of them were cathedral schools founded on church money. The church was all for science. Those 10 centuries paved the way for all of the advances that followed, from Galileo, Newton, and all the other heroes. Surely you’re not suggesting that someone in the 5th century could have been able to gather enough scientific evidence to support a heliocentric model. Just like science today, achievement has always been made by “standing on the shoulders of giants,” a phrase that dates back at least to the 12th century (reused famously by Newton in the 17th century) and refers both to the foundations of the Greek and Roman traditions but also to the quality and importance of the cathedral schools that educated “the moderns,” as they referred to themselves in that time.

            The thing that was dark about the dark ages is the lack of records compared to the preceding Roman Empire and contemporary cultures with relative political stability. They’re in the dark so you can’t see them, not dark like they were evil or backwards or something. Even Wikipedia will explain that scientific historians agree with this view of the Middle Ages.

            The whole thing with Galileo was obviously horrible, but that’s not how the Middle Ages were on the whole. You have to realize that during that time the church was a very political as well as religious organization, and Galileo challenged the church’s authority. That made him a political enemy. And at that time, house arrest was getting off easy. I’m not defending what the church did to him, but to say it was typical is simply false.

    1. Um…no. Unlike fission reactions, fusion reactions on Earth simply just don’t happen without a stupendously tremendous amount of help. Our current fission reactors are like a ball at the top of a hill. Let it roll a little too far one way and it stops. Too far the other way and it runs out of control. The control systems in fission reactor are designed to keep the ball at the top of the hill and away from out-of-control side of the hill. If the control systems fail, the ball could easily roll to the out-of-control side. Fission reactions once self-sustaining grows exponentially unless actively kept in check.

      Fusion reactors, on the other hand, are a ball on the not-working side of the infinitely tall hill–there is no out-of-control side. You have to keep pushing it up. If you let the ball roll, the reaction naturally just stops working. The control systems in a fusion reactor are trying to keep it going and if any part doesn’t work just right, the ball rolls to the bottom of not-working. Fusion reactions are not self-sustaining and cannot not grow by themselves.

      Unlike fission, getting a sustained fusion reaction is hard. Really, really hard. Trying to control all the factors to get a sustained fusion reaction is worst than herding cats. That’s why fusion has required many decades just to get a few minutes of plasma confinement without getting anywhere close to energy break-even whereas fission only took 9 years from conception to a sustained chain reaction.

    2. imagine explaining to someone from even the 1700 what we do with IC production (and the end result). They would just assume it was magic..They certainly wouldn’t think it was possible…

      We know fusion is physics possible. We just need the tools to do it – though I suspect that is going to be no time soon…

    3. I reported your comment a few days ago but it hasn’t been deleted. It is offensive and has nothing to do with the topic of the article or hacking, and I don’t think it belongs here.

      Please keep your opinions to yourself unless they are respectful and relevant.

  3. So something I’ve been wondering… how do you measure temperatures like this? I have to think a physical probe would be wrecked far too fast to get a reading, do they have a sensor set way back and just measure the radiative energy and math their way back to the temperature if they were measuring the middle of things?

    1. Shine a bright light like a laser in, it’ll scatter some and spread its wavelength based on temp of what it reflects thru, sorta. Mostly of electrons.

      Its pretty well ionized in there but not 100.0000% and the light spectrum you get from ionization depends on the amount of energy floating around in there. Your idea of total radiative energy is like the difference between measuring voltage vs current. Plasma not unlike fire; the color depends on the temp, but the total heat output depends on how much fire you got in there times how hot it is, so now you got the problem of determining how much is in there, which is a whole nother kettle of fish.

      If you inject neutral atom beam (at a real low flow rate not enough to shut the plasma down) as it ionizes and boils off and becomes part of the plasma it gives an interesting and predictable light spectrum based on temp.

      You can “trivially” measure neutron temperature and plenty of intended and unintended reactions involve neutrons flowing out of the container and you can work backwards to figure out the temp of reactants before they reacted. They definitely don’t come out as nice fission thermalized neutrons, much hotter!

    1. Though my brain was also saying “One fusion reactor may potentially regenerate fuel for dozens of fission reactors” as I was reading that. Then spent fuel from those is no longer waste. If fusion dependant on tritium from fission water, and can give fuel back to fission, then we’ve got a loop where waste from either source reduced.

      1. Could you expand on this? Fusion reactors are likely to be optimized for products that have a nuclear weight less than 8, and we have to spend a significant amount of energy once we go past a nuclear weight of 55, right? Unless we could scoop off emitted neutrons and use them to transmute targets, but then you get some random miasma of short halflife products, with an exceedingly small percentage of fissile or fissionable results.

        1. Well as described in link above, it seems not such a matter of scooping them off as having them flying everywhere unbidden. Unless of course the author accentuates how easy it is to enrich depleted fuels only as a scare tactic and it’s not actually something worth worrying about because 3kg a year of operation just by having spent fuel sitting there is 1000x too optimistic.

      1. It’s now called “muon catalyzed fusion”, and it only works if you do the math in strictly two dimensional space, and it requires hydrogen atoms with their electrons replaced with muons. In 3D space, the probability of the reaction is 1 billion times less likely, so the energy released by the process is absolutely minimal IF you could somehow produce “muonic tritium”.

        It has nothing to do with the earlier claims of cold fusion that claimed to cause fusion by having hydrogen atoms squeeze together inside platinum metal until they fuse. Later all sorts of quantum woo was introduced to keep the scam going.

        Here’s the trick: cold fusion was never “unpossible” – just the probability of it happening at close to room temperature was so low that the excess energy production in the amounts claimed were with absolute certainty, false. It would have been so low as to be completely indistinguishable from background noise.

        1. In other words: the woo-mongers don’t have a claim to the entire concept, although in practice they have tainted the name for all eternity, which is why you have to call it something else to be taken seriously.

          Just because you can show something can happen doesn’t mean all the people who had no clue are now vindicated in any sense. If you claim X causes some Y which isn’t observed, and someone else finds that Z causes Y which is now observed, the proof that Y exists in any sense doesn’t mean you were right about X or Y because you didn’t guess Y right. Your Y was a different thing from what was actually found.

          It’s like saying, “The moon is made of cheese!”, and after Apollo 11 backpedaling to say, “I told you the moon was made of basalt rock!”

    1. Over unity, perpetual motion, have fueled many dreams and ambitions… Might never succeed in the quest, but often something is gain, by taking that journey. May never get free energy, but there are improvements in efficiency.

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