Nuclear fusion... ten and a few years away?
Advances in magnet technology have enabled researchers at MIT to propose a new design for a practical compact tokamak fusion reactor — and it's one that might be realized in as little as a decade, they say. The era of practical fusion power, which could offer a nearly inexhaustible energy resource, may be coming near.
Using these new commercially available superconductors, rare-earth barium copper oxide (REBCO) superconducting tapes, to produce high-magnetic field coils "just ripples through the whole design," says Dennis Whyte, a professor of Nuclear Science and Engineering and director of MIT's Plasma Science and Fusion Center. "It changes the whole thing."
The stronger magnetic field makes it possible to produce the required magnetic confinement of the superhot plasma — that is, the working material of a fusion reaction — but in a much smaller device than those previously envisioned. The reduction in size, in turn, makes the whole system less expensive and faster to build, and also allows for some ingenious new features in the power plant design. The proposed reactor, using a tokamak (donut-shaped) geometry that is widely studied, is described in a paper in the journal Fusion Engineering and Design, co-authored by Whyte, PhD candidate Brandon Sorbom, and 11 others at MIT. The paper started as a design class taught by Whyte and became a student-led project after the class ended.
[...] While most characteristics of a system tend to vary in proportion to changes in dimensions, the effect of changes in the magnetic field on fusion reactions is much more extreme: The achievable fusion power increases according to the fourth power of the increase in the magnetic field. Thus, doubling the field would produce a 16-fold increase in the fusion power. "Any increase in the magnetic field gives you a huge win," Sorbom says. While the new superconductors do not produce quite a doubling of the field strength, they are strong enough to increase fusion power by about a factor of 10 compared to standard superconducting technology, Sorbom says. This dramatic improvement leads to a cascade of potential improvements in reactor design.
They are calling it an affordable, robust, compact (ARC) reactor. Presentation [PDF].
(Score: 1) by OrugTor on Tuesday August 11 2015, @03:59PM
Fusion is one of those things one should expect extreme difficulties in engineering the implementation. Given that this is a design within a class of yet-unrealized devices I'll stick with the traditional estimate of 30-40 years.
(Score: 2) by opinionated_science on Tuesday August 11 2015, @04:30PM
Prediction is of course not easy ;-) However, many of the predictions of the past did not have the exponential growth of computational modelling to aid in the design processes. For current fission reactors there is a huge intertia in building new reactors, such that there are designs in use from before the IBM PC. Just let that sink in for a bit. There is of course massive political interference in nuclear reactors, and perhaps not a bad idea, but the optimisation for security is not likely to yield better designs.
Hence, I would expect any practical fusion design to be a computational model first, especially since this design is much smaller, makes it "easier" to model (many simulations have volumetric element limitations).
The real problem is, any major success is likely to be used to prop up artificial scarcity, which is the current method for many legacy businesses to maintain profits...
(Score: 2) by DECbot on Tuesday August 11 2015, @10:09PM
So you're predicting that the output harmonic frequencies in the audible range will be recorded and copyrighted, and thus any operating fusion reactor will require a performance rebroadcasting license from the RIAA?
cats~$ sudo chown -R us /home/base
(Score: 2) by gnuman on Tuesday August 11 2015, @04:04PM
ITER is already getting built. Redesigning it doesn't make sense and US will never fund another experiment like that just because it's more compact.
New technological improvements could play a role for DEMO, once that finally arrives.
https://en.wikipedia.org/wiki/DEMO [wikipedia.org]
(Score: 4, Insightful) by takyon on Tuesday August 11 2015, @04:19PM
The point is that it is intended to be an AFFORDABLE, robust, and compact design. If a new fusion reactor design is orders of magnitude more cost efficient, there's no need to wait for $30 billion in government funding or the fate of ITER. It is well known that Lockheed Martin [bbc.com] and others [extremetech.com] are working on compact designs on a scale similar to this one.
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(Score: 2, Disagree) by ikanreed on Tuesday August 11 2015, @06:07PM
Right, and more importantly, they're fundamentally different principles involved.
ITER is inertial confinement, which is easily understood as shooting lasers from all directions at once to "push" atoms together.
This one and Lockheed are both magnetic confinement, using strong magnetic fields to create "barriers" that the atoms can't cross.
The focus fusion one you linked is electrical confinement, using a stream of electrons to create a "pinch".
So... if none of those have paid off yet, and all of them are theoretically plausible, there's no valid scientific reason not to pursue all of them.
(Score: 2, Informative) by Anonymous Coward on Tuesday August 11 2015, @06:19PM
ITER is not laser confinement fusion. ITER is a tokamak. Here:
http://lmgtfy.com/?q=ITER [lmgtfy.com]
http://lmgtfy.com/?q=ITER+Tokamak [lmgtfy.com]
http://lmgtfy.com/?q=ITER+laser+confinement+fusion [lmgtfy.com]
(Score: 1) by Eristone on Tuesday August 11 2015, @10:00PM
Does this make the new design an ARC reactor? (okay - couldn't resist)
(Score: 2) by takyon on Tuesday August 11 2015, @10:10PM
They couldn't resist first!
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(Score: 5, Interesting) by VLM on Tuesday August 11 2015, @04:09PM
Interesting to see their magnetic strength limited by material limits, stainless steel topping out around 500 MPA on planet earth (ha ha at their graph implying 1 GPA for stainless steel) means they're going to be limited to below 20T at any factor of safety greater than 1 (LOL). Of course there are high nickel content steels about 4+ times stronger than stainless and weird composites although I'm sure there are interesting magnetic implications. I've seen A11 tool steel advertised over 5 GPA so that would be darn near ten times as strong as their assumed stainless steel limit. Tool steel usually has excellent high temp qualities too, unlike cruder steels.
I think using old imperial measurements 8 GPA of stress is about a million PSI. So imagine a COTS exotic-steel cable a bit over an inch wide on a crane holding up a million pounds and not snapping. That's the kind of stuff it takes hold a reactor together.
So they have some interesting material choice decisions to make, giving up on traditional stainless might be required. Magnetic effects, outgassing into vacuum, etc.
Assuming their little linear graph goes up and to the right infinitely (LOL) that would imply making their magnet out of exotic tool steel instead of stainless they could realistically get up to 40+ Tesla. Looking at the current world records for magnets, well, that's right about where they are, so it sounds pretty reasonable...
That means they could extend their analysis, "assuming deliverable 30T to 40T instead of 20T..."
I also liked the part that implied if they don't fund this thing to study plasma exhaust, they're going to have to fund something other than this to study plasma exhaust for the bigger project so may as well just toss some money to them because if they hurt ITER's feelings they're gonna have to pay someone else to do it anyway, which I kinda LOLed at a bit.
(Score: 2, Informative) by Anonymous Coward on Tuesday August 11 2015, @04:27PM
It took me a bit of time until I understood that your "GPA" were meant to be "GPa", that is, "Gigapascal". In units, case matters!
(Score: 2) by takyon on Tuesday August 11 2015, @04:38PM
Heaven forbid we step on the toes of the expensive and delayed ITER with approaches that are orders of magnitude cheaper. We wouldn't want to hurt anyone's feelings or budget by getting practical fusion to market faster.
http://www.bbc.com/news/science-environment-29710811 [bbc.com]
http://www.extremetech.com/extreme/184280-focus-fusion-has-cheap-clean-earth-saving-fusion-power-been-right-under-our-noses-all-along [extremetech.com]
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(Score: 2) by gnuman on Tuesday August 11 2015, @04:48PM
Magnets are not the problem with ITER. Or even the money. The problem with ITER is that it's not proven technology. Science has to be done and finished before anyone will spend billions making more compact fusion reactors.
If ITER is costing something like $20B, then "compact DEMO" that's "order of magnitude cheaper" will cost what? $5-10B? And it certainly will not fit in your pocket!
(Score: 2) by takyon on Tuesday August 11 2015, @04:59PM
http://lawrencevilleplasmaphysics.com/cost-advantage-roi/ [lawrencevilleplasmaphysics.com]
http://lawrencevilleplasmaphysics.com/lpp-executive-summary/ [lawrencevilleplasmaphysics.com]
https://en.wikipedia.org/wiki/High_beta_fusion_reactor [wikipedia.org]
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(Score: 2) by VLM on Tuesday August 11 2015, @05:58PM
Yeah I donno about the wikipedia article, where its claimed you can't build a mobile breeder because the breeding blanket weighs a kiloton but there seems to be no explanation why you can't build a non-breeding mobile. In fact, to get a mobile space reactor or submarine reactor, countries would probably burn coal to generate tritium just to get the mobile fusion power if they had to (although in practice you'd just consider a multi kilo ton breeder blanket either a national strategic asset paid for by .gov or if someone outside the USA tried it you'd call it a proliferation risk and bomb them, depending on perspective).
You need some shielding or you'll Cherenkov radiate like a searchlight, at least for a submarine. I recall that was in the plot line of "Ghost Fleet".
The dual mirror is innovative. Its a typical undergrad textbook thing to prove a single mirror device will never break even or the break even size is like a bazillion free paths such that you'd need a simple single mirror machine the length of Texas. You could cross eyes some and say its a segment of an unrolled tokamak, well, that would take a lot of eye crossing, but its not that bad of an analogy.
(Score: 2) by takyon on Tuesday August 11 2015, @06:01PM
I'm interested in the parts I blockquoted, and you can find other reporting on Lockheed's fusion plans. Indications are they think they can commercialize a small-scale shipping container sized nuclear fusion reactor.
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(Score: 2) by VLM on Tuesday August 11 2015, @06:23PM
Right right I think we agree on the good parts. Will be very interesting to see what happens with these guys. There are merely aspects of the wiki article that are non sequitur.
I suspect "shipping crate sized" means our Navy will fund it and we'll see nothing for quite awhile. Its like they were fishing for the Navy with bait. I suppose all branches have their reasons for finding it a tasty piece of bait, except perhaps for the air force of our navy's army aka the USMC air corps.
(Score: 2) by takyon on Tuesday August 11 2015, @06:34PM
The Navy likes the taste of fusion bait so much, they are apparently looking into cold fusion/LENR:
https://en.wikipedia.org/wiki/Cold_fusion#United_States [wikipedia.org]
https://www.google.com/?gws_rd=ssl#q=navy+cold+fusion [google.com]
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(Score: 3, Informative) by VLM on Tuesday August 11 2015, @07:00PM
The navy has (had?) a thing for the polywell/fusor approach too.
That's another one of those "works so well it fell off the face of the earth" technologies.
Last I heard WB-8 exceeded all contract expectations so the next step was (insert radio silence here).
I'm sure when they resurface the stories about WB-9 will be interesting to hear, hope there's good results.
Fusors don't get much love from the conventional people because they're not the politically correct tokamak or even a mirror, and they don't get any love from the conspiracy theorists because they're already commercially successful and shipping controllable neutron sources and you can't stick it to the Man when the Man is selling commercialized portable neutron sources.
Fusor = orphan of fusion research yet is also another naval research fusion operation.
(Score: 2) by VLM on Tuesday August 11 2015, @06:12PM
The problem with ITER is that it's not proven technology.
In all fairness I looked it up and ITER isn't supposed to run above 13 T which isn't that big of a deal anymore. Well, its not building subwoofers and fridge magnets but its not a big deal anymore.
The linked article is basically speculation on "well, if it takes 30 years to build a 13 T reactor because its Fing huge, then how long could we expect it to take to make a 20T to 30T reactor" knowing that the scaling factors are absolutely insane so you could probably put a 50T reactor on your desktop (I haven't run the numbers, but that would be funny). In my infinite spare time it would be funny to run the numbers, how high of a field strength would it take to make a fusion reactor smaller than a phone? Now at gigawatt level radiation you'd die pretty quick, but at a billion times lower output and a billion times lower radiation maybe...
It makes a fun ultra hard sci fi story, so tomorrow we discover compressed unicorn poop makes 500 T magnetic fields, what happens next? Well, aside from chemistry lab NMRs operating at like 100 THz, etc etc.
A good space analogy is its the old worry about colonization ships where you send a generation ship on the slow boat to Alpha Centauri which will take dozens of generations and many centuries and they're gonna be real pissed off when the Enterprise drops out of warp in two hundred years and home is just a 9 minute flight back or WTF. So the fastest way to get to the nearest star is not to launch anything for a couple centuries, which is paradoxical but true.
(Score: 1) by khallow on Tuesday August 11 2015, @09:05PM
The problem with ITER is that it's not proven technology.
The problem with ITER is that even if it works as advertised, it won't do a thing to progress towards a commercially viable fusion power source aside perhaps from a bit of high temperature plasma dynamics.
If ITER is costing something like $20B, then "compact DEMO" that's "order of magnitude cheaper" will cost what?
$2B. That what order of magnitude cheaper means.
For me, the huge price difference is not the compact design but the fact that the superconducting REBCO magnets don't need to be run at liquid helium temperatures. I don't know whether they can be run at liquid nitrogen temperatures (I gather there is some need to cool magnets which are operating near their limits well below the nominal superconducting temperature threshold), but if they can, that will make the project vastly cheaper.
(Score: 2) by mhajicek on Wednesday August 12 2015, @02:52AM
Well, they started producing F35s well before the design was finished, let alone tested. they put a lot more money into that, and now they'll have a bunch of expensive hanger queens for airshows.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 0) by Anonymous Coward on Tuesday August 11 2015, @05:46PM
Steel-nickel alloys or "Nickel steel" as you put it is a subcategory of stainless. Tool steel has been common for a century and some varieties overlap with stainless. For all that boasting and googling there really isn't much accuracy in your post.
(Score: 3, Informative) by fnj on Tuesday August 11 2015, @07:15PM
Bull. Typical mechanical properties for 17-4PH [azom.com], annealed: UTS 1100 MPa, Proof 1000 MPa, elongation 15%. And 1310/1170 with 10% elongation at Condition 900. And there are stronger precipitation hardening alloys than that.
(Score: 2) by VLM on Tuesday August 11 2015, @08:02PM
I admit defeat. Cheap stuff without proper heat treat was probably a bad expectation for a nuclear reactor. Still the greater point stands that there are a lot stronger things than stainless steel they could use to their advantage, if they are, per the pdf, tensile strength limited. I wonder if they'd need a liner of SS for some kind of corrosion, plasma, or vacuum issue that could make fabrication more expensive.
And it also still rolls back to what factor of safety they designed into their scaling equations (my gut level guess is "1") so in practice...
(Score: 2) by mhajicek on Wednesday August 12 2015, @02:56AM
Steels with that much tensile strength tend to be extremely brittle. I would be extremely nervous around it; a little uneven thermal expansion and it could explode.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 2) by Zinho on Tuesday August 11 2015, @04:34PM
What they mean when they say 10 years... [xkcd.com]
Is someone familiar enough with the design of these fusion reactors to explain how they intend to get the heat out of the reaction chamber? Eventually the point of this exercise is to boil water to spin a turbine. From what I've seen, we've so far had a bunch of difficulty even getting the reaction to be self-sustaining; extracting "waste heat" seems to be a "we'll cross that bridge when we get to it" sort of issue.
So, Lentils, any insights?
"Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
(Score: 3, Interesting) by Immerman on Tuesday August 11 2015, @05:35PM
My general understanding is that extracting heat is generally left as a "we'll cross that bridge when we get to it" sort of issue because it's (relatively) trivial to do. The technology for moving heat around has been pretty well refined over the past couple of centuries. There may be some material science challenges, but basically any cooling system suitable for a fission reactor should translate fairly well to a fusion reactor as well - the neutron flux per watt is only a few times higher after all.
In addition, for many fusion devices the eventual goal is proton-boron fusion, in which case virtually all of the energy is released as high-speed helium-4 nuclei from which the energy can be electrostatically extracted, virtually eliminating heat from the energy-producing reaction, and relegating cooling systems to dissipating the waste heat produced by the control and containment systems.
(Score: 3, Interesting) by Zinho on Wednesday August 12 2015, @01:42PM
Thanks for the reply. Part of the reason I was asking is that fusion reactors have some unique challenges that don't apply to fission plants. The fusion containment bottle is very "hands-off": the plasma (while very energetic) doesn't have a lot of mass, and if the plasma touches anything it cools off to the point that that the reaction stops. In contrast, the fuel rods in a typical fusion reactor don't much care if you snuggle a coolant loop up against them beyond how well the coolant absorbs/reflects/slows down any neutrons flying around.
I was able to do some research, and it seems that the plan for how to collect energy from a tokamak is to run pipes of liquid Lithium through the containment vessel walls and use them to capture high-energy neutrons created by the fusion. Since the neutrons are at very high temperature, the neutron capture itself is the primary method of heat capture for the reactor. After the neutrons are captured the Lithium undergoes beta decay with Helium and Tritium as byproducts, which serves as a sustainable source of Tritium to feed the reactor. The waste helium you mention is retained temporarily in the containment bottle to keep the temperature up, but is eventually cycled out as a waste product (how they do this without shutting down the reactor is still a mystery to me).
That neutron capture trick was not obvious to me, and kinda blows my mind. It's a great solution for the "no touchee" problem, and certainly gets the job done. As you said, this is a solved problem which explains why it doesn't get talked about much.
"Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
(Score: 2) by Immerman on Thursday August 13 2015, @05:17PM
Okay, I understand your question better now, perhaps I can expand a bit on what you've learned (which was quite interesting, I hadn't known the details). In a fission reaction a fair fraction of the reaction energy remains trapped within the solid fuel since the large nucleus fragments can't escape and their kinetic energy is immediately thermalized, and thus your coolant must be in contact with the fuel rods to avoid having them melt down into an uncontrollable pool of fuel. Or alternately, in a liquid-fuel reactor, the fragments are much more free to move and the energy is thermalized over a larger area, reducing "hot spots". And obviously a meltdown is a non-issue when the fuel is already molten. Same basic idea though, you've just dissolved your fuel into the coolant to simplify things.
By contrast, in a plasma-based fusion reaction nothing is restraining the fusion products except the magnetic containment field that's barely able to adequately contain the source plasma. Dump a bunch more kinetic energy into a product particle and most can escape containment without much trouble. To say nothing of free neutrons which tend to make up the majority of such particle radiation and are largely immune to magnetic containment due to their lack of charge (they do have a magnetic moment, but magnetically containing magnets is a very different mechanism than charged particles)
In most* reactions though, fission or fusion, the majority of the energy tends to escape as non-particle radiation: high-energy photons in the X-ray and gamma ray spectrum that can pass through a significant amount of matter before being absorbed. That's what all the lead shielding around a nuclear reactor is there to stop. Particle radiation, even neutrons, is unlikely to penetrate even a thin piece of sheet metal. Most of the high energy photons though will easily pass through plasmas, fuel rods, magnetic containment, and the structural walls of the reaction vessel. They mostly get absorbed by the shielding and/or the coolant itself, and the heat is then put to work.
*Fusion is a little different in that most reactions tends to create a lot more free neutrons per watt, and thus capturing them is more important to energy recovery. There are also some reactions, such as the proton-Boron I previously mentioned, where there is very little photon radiation as well, and thus virtually all of the energy is released as kinetic energy of the products. p-B being special in that all the products are identical He4 nuclei with a very narrow range of kinetic energies, and thus electrostatic energy conversion is extremely viable and most of that pesky inefficient heat can be avoided altogether.
(Score: 3, Funny) by Tork on Tuesday August 11 2015, @04:36PM
Slashdolt Logic: "25 year old jokes about sharks and lasers are +5, Funny." 💩
(Score: 3, Informative) by deadstick on Tuesday August 11 2015, @04:42PM
No, it's a Russian contraction for "toroidal chamber with magnetic coils" (sorry if you were just joking). But a Republican congressman made an ass of himself back in the 80's when he thought it was an American invention because it seemed to have an American Indian name.
(Score: 2) by Tork on Tuesday August 11 2015, @05:19PM
Slashdolt Logic: "25 year old jokes about sharks and lasers are +5, Funny." 💩
(Score: 1) by meustrus on Tuesday August 11 2015, @04:45PM
The word tokamak is a transliteration of the Russian word токамак, an acronym of either:
or
If there isn't at least one reference or primary source, it's not +1 Informative. Maybe the underused +1 Interesting?
(Score: 2) by Username on Tuesday August 11 2015, @06:18PM
First, Romulan names do not commonly end in K, that is a naming convention for Vulcan males. The logic behind this is that Vulcans follow the teachings of Surak, while Romulans do not.
Second, Romulans use the gravitational pull of an artificial singularity as their energy matrix, while Vulcan (Federation) uses plasma from deuterium fusion reactors and deuterium warp drives routed through EPS conduit and plasma relays to power converters and matter replicators.
Gah, some people just cant tell the difference between a warp matrix flux capacitor and a self-sealing stem bolt.
(Score: 2) by Tork on Tuesday August 11 2015, @06:30PM
First, Romulan names do not commonly end in K...
Mm hm. [wikia.com]
Gah, some people just cant tell the difference between a warp matrix flux capacitor and a self-sealing stem bolt.
Oh yeah? Well... double dumb-ass on you!
Slashdolt Logic: "25 year old jokes about sharks and lasers are +5, Funny." 💩
(Score: 2) by Thexalon on Tuesday August 11 2015, @06:24PM
As the old saw goes, nuclear fusion is 10 years away ... and always will be!
Also, the last time somebody announced something similar to this [wikipedia.org], it turned out to not be anything remotely similar to what the announcement said it was.
As far as industrial and commercial use goes, why not instead focus on using existing technology to collect power from that really large fusion reactor safely ~98 million miles away?
The only thing that stops a bad guy with a compiler is a good guy with a compiler.
(Score: 2) by takyon on Tuesday August 11 2015, @06:35PM
This is hot fusion
http://www.bbc.com/news/science-environment-29710811 [bbc.com]
http://www.extremetech.com/extreme/184280-focus-fusion-has-cheap-clean-earth-saving-fusion-power-been-right-under-our-noses-all-along [extremetech.com]
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(Score: 3, Insightful) by pkrasimirov on Tuesday August 11 2015, @06:35PM
> why not instead focus on using existing technology to collect power from that really large fusion reactor safely ~98 million miles away?
Because when you go to Pluto, or even Mars, this reactor is not so close and the received energy tends to be insufficient.
(Score: 2) by BananaPhone on Tuesday August 11 2015, @06:41PM
You can get funding up the wazoo for unproven Fusion project but you can't even get a commitment for a LFTR reactor?
(Score: 0) by Anonymous Coward on Tuesday August 11 2015, @09:07PM
LFTR and other big projects are currently begin developed by the countries capable and willing of constructing and maintaining such infrastructure like China and India.
As for the USA, I understand congress is finally getting ready to approve the budget necessary to fix the pot-holes in the interstate after 2years of deliberations and committee meetings.
(Score: 2, Funny) by cmdrklarg on Tuesday August 11 2015, @08:54PM
Excellent, I expect to see some powered armor in gold and hot rod red soon thereafter.
Answer now is don't give in; aim for a new tomorrow.