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MIT's Pathway to Fusion Energy (IAP 2017) - Zach Hartwig

MIT Plasma Science and Fusion Center · Youtube · 139 HN points · 43 HN comments
HN Theater has aggregated all Hacker News stories and comments that mention MIT Plasma Science and Fusion Center's video "MIT's Pathway to Fusion Energy (IAP 2017) - Zach Hartwig".
Youtube Summary
Fusion energy and MIT's pathway for accelerated demonstration with high-magnetic field tokamaks

An introduction to the key concepts of producing clean, safe, and carbon-free electricity from magnetic fusion energy. This talk reviews the present state of fusion energy research and then introduce MIT's proposed pathway to use high-field superconducting magnets to achieve fusion energy at smaller unit size, at lower cost, and on a timescale relevant to climate change.
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All the comments and stories posted to Hacker News that reference this video.
Small tokamaks are what I think are potentially viable, a la Commonwealth Fusion Systems.

Here's a good talk that I think addresses the physics vs engineering approaches to fusion.

https://youtu.be/L0KuAx1COEk

joak
I do think tomakaks are possible. CFS and Tokamak Energy are getting there fast.

But the 50MW shipping container size generator planned by Helion would be really transformative. No need to build near a river to cool. Order from the factory, get delivered, install.

https://www.reddit.com/r/fusion/comments/ukeisj/if_polaris_h...

Jul 13, 2022 · elsherbini on Helion Needs You
As a very much non-nuclear engineer, I found this video [1] explaining different fuels, size, magnetic field strength, and the orders of magnitude physics and engineering that goes into current fusion efforts.

Curious where Helion would put themselves on the nτE vs ion temperature plot he uses to evaluate how feasible a technology is.

[1] https://www.youtube.com/watch?v=L0KuAx1COEk [2] https://en.wikipedia.org/wiki/Fusion_energy_gain_factor

willis936
Hartwig gave a similar talk for SULI a few weeks ago. Really awesome stuff and accessible too. Note that he is assuming steady state confinement. Fuel viability is a more complex beast for high-density low-confinement-time plasmas.

Scroll down for table of lectures.

https://suli.pppl.gov/2022/course/

Slides

https://suli.pppl.gov/2022/course/IntroductionToFusionEnergy...

Video

https://mediacentral.princeton.edu/id/1_u3eelkrl

disclaimer: I am not a fusion scientist, nor even a physicist. Just a bystander who has been following this closely for years.

But: Yes. Just one of those avenues is what MIT's Plasma Science and Fusion Center[0] has been talking about publicly since at least 2017 -- here's a fantastic talk[1] by them about how to think about fusion research and engineering, different approaches available, and about what is different in a world of high strength magnetic tapes, which they have subsequently worked to produce at industrial scales in partnership with CFS[2][3], which was founded by people from the PSFC to take advantage of this research. The bottom line is: these new very strong magnets allow way, way smaller tokamaks to hit net positive.

The hard research here is mostly done. The magnets it gave us have cleared a path forward at a far more tractable time and complexity scale than ITER can dream of. The work is now an engineering and industrial process problem, which is well under way: serious scientists and engineers around the world are hard at work at over a dozen different startups, working on reactors that could fire net-positively in well under a decade.

Will those reactors fix our energy problems? Hey, there's still fuel, waste, maintenance (neutrons hit hard!), regulations, etc... -- commercialization and politics are their own whole problems. But I would absolutely take the long bet that we'll have at least one net positive tokamak running before 2030.

0 - https://www.psfc.mit.edu/sparc

1 - https://www.youtube.com/watch?v=L0KuAx1COEk (really, if you're at all interested, this is simply an amazing talk and clarifies a lot)

2 - https://news.mit.edu/2021/MIT-CFS-major-advance-toward-fusio...

3 - https://www.cfs.energy/ -- you can see Bob Mumgaard, CFS'CEO, is listed as a speaker at the white house event

ncmncm
But: No. Even if every single thing they hope to get working were to work perfectly the first time, there would still be no commercially competitive power out of it.

If they offered the power exactly at cost, they would get no bids. Fission is today not competitive, and nobody involved can promise that Tokamak fusion could ever be competitive even with fission, never mind with what renewable power will be priced at, by then.

So, no, those reactors will not fix our energy, or any other, problem, unless our problem is too much money and not enough things to waste it on.

wcarss
Supposing you're discussing in good faith, I'll engage with you, and _agree_: for the near term, I do not believe that fusion will be a commercially viable competitor to wind and/or solar. Not within 10, 20, 30, or even 50 years. I also agree that it likely won't beat the dollar-cost of fission power in that timeframe. But I do think it will replace fission for most new power projects somewhere within that timeframe, especially in developing nations.

The expensive thing about fission is not getting a fission reactor to work, nor keeping it running. It's in getting the reactor greenlit at all, bespoke-designed, and handling supply and waste management. In many places, it is simply not an option due to geopolitics. So fission problem is not impractical because it is cost-prohibitive. Instead, it is impractical because it is responsible-waste-management and weapons-proliferation-regulations and spooky-stuff-difficult-political-battle-PR-nightmares-prohibitive. Sadly, very few people a) want a nuclear reactor in town, b) want to shoulder the risk of building, maintaining, and staffing a fission plant for 50 years, or c) want any "risky" nations to have easy access to them. That, far more than dollar-cost-per-megawatt-hour, is why we don't have nuclear plants everywhere today.

Solar and wind are amazing, and obviously essential to any future we have, but today they cannot do everything, everywhere. Further revolutions in power storage and transmission might enable that (like huge flywheels?) but that's not what we're discussing, we're discussing whether fusion a) can work, b) is useful at all, and c) will ever see large scale use for power production. I do grant that it's _possible_ that a flywheel-revolution could outpace a fusion-revolution.

Because of fission's problems, the niche of fusion over the next 30-50 years may be "nuclear power, but safer": it's more expensive, but it can be sold or built anywhere, the fuel control is not so vital/tough, and the waste is handleable on a timescale we can _at least_ wrap our heads around. Wind and solar currently need baseline plants for supplementation, and fusion may be the ticket to turning off the last remaining gas and coal plants out there, or in supplying power to underpowered nations with less favourable conditions for wind and solar. That is wonderful! That is lightning in a goddamned bottle. Literally! Does it have to be the cheapest option, when for many it's the only option?

Past 50 years, well, history would suggest it'll likely get better. Fission would likely be a lot better today (read: cheaper, smaller) if it were safer to begin with, and solar and wind have gotten astoundingly cheap as they've seen investment and use expand over time, so why shouldn't fusion do the same?

So the argument is: we're now likely to get net-positive tokamaks by ~2030. And if we have any net-positive tokamaks by 2030, then they can likely fill a power-niche that fission just can't. And if we spend 50 years making fusion plants and proliferating the technology, by 2080 it might get pretty damn cost effective. I think that's the bet all these smart people are making, and personally, I'm inclined to take it.

pfdietz
> Solar and wind are amazing, and obviously essential to any future we have, but today they cannot do everything, everywhere.

Well, with storage, they can do everything, everywhere. At worst, you make chemical fuels and ship them off to any weird place that has no sun and wind.

And PV is making electricity at $0.013/kWh in Dubai. Fusion will be lucky to come in within an order of magnitude of that.

ncmncm
The most expensive and difficult thing about fission is, always, getting it built. It is so very expensive that, often, we give up after spending, literally, billions of dollars beyond what had been projected for completion. Other costs are also high, and seem small only by comparison. Fusion projects promise to cost an order of magnitude more than fission to build, and correspondingly more to operate.

Any place where renewables, local storage, and power delivered via transmission line are all unavailable, even if only temporarily, can surely get by on synthetic fuel shipped in from places that have reliable-enough power to make and stockpile that. So, it is hard to understand a claim that extremely cheap renewables "cannot do everything, everywhere." Indeed, we all are long used to relying on liquid fuels shipped in from across the globe, and I do not know why we would abandon the capacity.

I also see no need for extremely expensive "baseline plants" when the cost for storage is falling much faster, even, than the cost of the energy to be stored. Besides the very mature pumped hydro, we may turn the similarly mature liquified-air technology to storage. Factories for iron-air batteries are under construction. Synthetic hydrogen, methane, ammonia and even kerosene are known to be practical. Even long-distance transmission will often be a cheap substitute for drawing down storage stocks.

While chemical storage is less "round-trip" efficient than some other alternatives, it offers the important advantages that, when the tanks are full, the product is always immediately useful industrially, so synthesis equipment need almost never sit idle; and extra tanks are very cheap, anywhere more would be useful. Synthesis efficiency will only ever improve.

So, supposing somebody did manage to get "net-positive" Tokamak fusion as early as 2030, it is hard to imagine who would still care, by then. Do wake me up, though, if you find a way to get aneutronic D-3He fusion going that I can use for outer solar system operations.

fallingknife
You just keep saying this, but never provide a shred of evidence.
ncmncm
Evidence is all just a click away, if you care to know.
This has been by far the most informative source on Fusion I've seen and gives a clear picture on how to evaluate claims like this.

MIT's Pathway to Fusion Energy (IAP 2017) - Zach Hartwig

https://youtu.be/L0KuAx1COEk

https://www.youtube.com/watch?v=L0KuAx1COEk

https://www.reddit.com/r/fusion/comments/67rqqg/comment/dgtm...

"For the record The Bulletin of Atomic Scientists is a [sic] anti-nuclear advocacy group. They often resort to fear mongering or using the straw man fallacy to advocate their point."

https://news.ycombinator.com/item?id=14203206

chadcmulligan
Thats good, thanks
If anyone have not seen it i recommend this video as a primer for fusion technology, it's from MIT. https://www.youtube.com/watch?v=L0KuAx1COEk

The video thouches upon magnetic fields and its relevance at this time mark ; https://youtu.be/L0KuAx1COEk?t=2880

I haven't seen that one, but here's another talk on the same topic in the context of fusion energy broadly, by some people involved https://www.youtube.com/watch?v=L0KuAx1COEk
Serious question: how does an article like this get written without mentioning SPARC[1] once? They're hardly secretive, they're MIT's people, they're moving on a plan to get results in ~5 years, and they're talking about the same kind of things: tokamaks, better computer modeling, and easier to make higher temperature superconductors for stronger magnets.

I'm just a layperson, I only know pop science level stuff here, but they seem clearly like the best game in town -- so, seriously, can a person in the physics world shed some light on why they aren't at least a small part of every article about fusion, but ITER is?

1 - https://en.m.wikipedia.org/wiki/SPARC_(tokamak)

(And, for those with an interest who still haven't seen Zach Hartwig's absolutely excellent 2017 talk: https://youtu.be/L0KuAx1COEk -- watch it!)

free_rms
God I wish we could Manhattan Project this shit. I'm a layman too but I get the impression that the theory is basically there and we just need to figure out the engineering. That's a solvable problem with lots of money and lots of teams.

Are we going to wait until the sea level rises 20 feet and then say, geez, compared to the costs this imposed, fusion would have been easy?

kortilla
Fission is a solved engineering and science problem though and we’re still blocking it to let the sea levels rise. Point being, nobody actually cares about climate change enough to make hard decisions so a Manhattan style project is highly unlikely.
dchichkov
Is there a way to make people care?

Personally, I think, for United States it does make perfect sense to redirect, say, half of the military budget onto solving real homeland security issues: climate change, sustainability, ecology, pandemics. There might be enough budget there to address climate change [1].

It'd be a risk to spend less on military, but considering that the United States has nuclear weapons and allies, is it a risk really?

[1] https://www.nature.com/articles/d41586-020-02460-9

entropicdrifter
The real risk is politicians not getting their kickbacks from defense suppliers, sadly. The military industrial complex that Eisenhower warned us about has a death-grip on the congressional budget, even against the wishes of Pentagon leaders.
hunter-gatherer
A month or so ago I was listening to an NPR interview about insects. The interviewee said that the insect population in Germany has declined something like 75% in 25 years. He noted that people don't tend to notice big changes over the span of a couple decades, which is a good point, and helps explain why climate change will probably never be seriously tackled.

Edit- link to article: https://www.theguardian.com/environment/2017/oct/18/warning-...

api
It will be tackled through adaptation. Some coastal cities may die. Others may have to spend a ton on remediation. More people will migrate inland, and farming centers will shift.

It’s far too late to stop it with prevention, though there is still value in trying to cut CO2 when possible to blunt it a bit.

numpad0
Politics, NIMBY, risks of accidents, and radioactive materials pollution are unsolved problems. You could argue it’s sociology than engineering but a problem nonetheless.

I think nukes is the future but nukes belong in space; just build some fission on high orbit to perfect fusion, and bring the meat down over microwave or as bulk hydrocarbons or whatever that works.

Solar system has unlimited free meal supplies of raw materials on first-come-first-serve basis. It’s been said that extraterrestrially constructed spacecraft can be launched for free merely by gently pushing it out of dockyard, or at most shooting out of a maglev train, for at least half a century.

So build some gigantic fission satellites in space!

vladTheInhaler
Why do fission in orbit when you have unimpeded access to a huge natural fusion plant, and virtually unlimited real estate to harvest its energy?
imtringued
People underestimate what 21% efficient means when it comes to solar panels... If you bring a solar panel to space and receive sunlight 24/7 at 44% higher intensity than the best place on earth you will generate an obscene amount of electricity.
Lammy
> You could argue it’s sociology than engineering but a problem nonetheless.

It can be both when the consent is manufactured! :)

orthecreedence
Yes, I've been saying it over and over: raise the price of oil until gasoline et al are $20+/gallon. Then nuclear will be cheap.

Why are we letting a silly thing like scarcity, supply, and demand dictate whether we self-destruct?

nine_k
Most fossil-based electric generation is not oil; it's either natural gas (reasonably clean, though it does produce a lot of CO₂), or coal (terrible on many counts).

I'd say that killing coal would have a large effect. It would also put entire town populations out of work — a really hard problem, read about how UK tackled it in 1970s and 1980s, it was painful and ugly.

pjc50
The death of UK coal was all to do with economics of importing coal and labour prices and relations, rather than climate change. But also that's why most green parties talk of a "just transition", subsidy to the workers who will lose their jobs.
hardlianotion
It was also to do with cleaner energy generation and taking advantage of natural gas resources in North Sea. Dash to Gas was a major enabler of the switch away from coal in the 90s.
DennisP
At the end of 2016 there were 50,000 coal miners in the US.[1] Their average annual pay is $29K.[2] We could give each of them one million dollars, invested and paying out 3% annually, and the $50B it costs would be a drop in the bucket compared to the economic benefit of eliminating those carbon emissions.

In fact, it would even be cheaper than the healthcare costs of pollution from coal plants, which amounts to $187 billion in the U.S.[3] And in Appalachia, healthcare costs from coal production are $75B annually, so we'd come out ahead there too, which would be a double benefit for the miners since they'd be both richer and healthier.

[1] https://en.wikipedia.org/wiki/Coal_mining_in_the_United_Stat...

[2] https://www.glassdoor.com/Salaries/coal-miner-salary-SRCH_KO...

[3] https://e360.yale.edu/digest/coal-costs-us-half-trillion-ann...

entropicdrifter
Yeah, but that's a logical, pragmatic solution that actually looks at the cost-benefit from a scientifically informed perspective. Most (or at least half) of America would hate it.
tuatoru
> Then nuclear will be cheap.

But it still won't be built, because Solar PV and wind are roughly two-thirds the cost and falling. (Including the cost of backup power supplies for periods of low sun or low wind.)

(Not to mention having much shorter construction times until first revenue, lower delay risk, lower investment risk, and lower operation and maintenance costs.)

Nuclear had its chance in the 1990s. Today, we have cheaper and better options.

jdeibele
I've been saying for a long time that the US should increase the tax on gas steadily every year. Even a nickel a year would be OK but more would be better.

People would be able to plan on the price increasing every year and make sound economic decisions on whether they wanted to move closer to work, etc.

Unfortunately, it became apparent about the same time that the US is almost incapable of doing something in an organized fashion. People would scream about the price of gas going up and it would be rolled back. Or there'd be subsidies that would negate the tax increases.

Mediterraneo10
Fuel in the US is already much more expensive than two decades ago. I remember buying a gallon for around 90 cents in 1999, and at the same time I read a newspaper article about some immigrant-run stations on the Jersey shore that had slashed their prices to several cents below that, as they were content to make a tiny profit margin and play a long game. Now a gallon costs more than twice as much as then, but as far as I can tell the average American has not made significant lifestyle changes with regard to vehicle usage: they just suck it up.
smichel17
...and I remember paying almost $4/gallon, around 10 years ago (I think), with no expectation that the price would drop. Gas is crazy cheap rift now.
Xorlev
$0.90 in 1999 is $1.41 today. Near me, gas is ~$2 (give or take). So, more expensive (~40-50%), but not double.
jsight
0.90 is also an outlier for 1999. The average price was closer to $1.20 back then.
jacquesm
Here it's closer to $2 / liter. (1/4 of a Gallon).
tremon
Sure, but your "here" isn't in the US.
jacquesm
Indeed, which is why I provided that datapoint.
Mediterraneo10
Granted, it may not be quite double, but average American salaries have not entirely kept pace with inflation in the last twenty years, so fuel expenses are appreciably higher than simply counting the inflation in.
olau
Fusion is not going to solve the sea level rise problem.

You can see this by comparing it to fission.

Fission fuels is not expensive on a kWh base, so cheaper fuel is not really a big advantage.

Fusion plants produce radioactive waste too (perhaps less?), so you don't save yourself from that headache. Which isn't actually that big of a problem either, even if the costs are probably underestimated for fission plants.

Now, the real killer for fission is the cost of the plants. They are just so incredibly complex and expensive that they are not competitive.

Will a fusion plant be cheaper? Probably not. It will most likely, with current tech, be much more expensive. So it won't be able to compete with fission. And fission can't compete (in most parts of the world) with renewables, that are still falling exponentially in price.

So fusion may still be interesting from a scientific stand point, and perhaps things will change in the far future.

An argument I often see is that renewables need storage, and that's true. But so does a fission or a fusion plant, unless you overbuild and accept a bad capacity factor. Some amount of overbuild combined with storage looks like the most economical solution currently - the specifics depend very much on where you are in the world.

deweller
Fusion does not create any long-lived radioactive waste.
tyho
No, but fast neutrons are created in some processes which induce long lived radiation in reactor materials though.
willis936
100 years is not “long lived” in the context of radioactive waste disposal.

http://www.acamedia.info/sciences/J_G/fusion.html

pfdietz
Fusion will likely produce a larger volume of waste contaminated enough to prevent easy disposal. That could very well make the waste more expensive to deal with.
fennecfoxen
Fission is too expensive because everyone tried to get economies of scale at big complex custom-built one-off plants. Those who see hope for fission look to get economies of scale with a modular approach, mass-producing simple, small, reactors, shipping them from the factory to the site on trucks, and attaching them to the grid.

I am not qualified to assess whether that hope is well-founded, but there are real differences in the approach.

marcosdumay
Big nuclear reactors are cheaper on the $/MW metric than small ones. Big steam power plants are also cheaper on the $/MW than small ones.

It's not that clear how much economy of scale is there with a modular design and if it's enough to displace the diseconomy of making smaller plants. But the one thing that gets cheaper with a small size is safety mechanisms, and those are a big thing.

Gwypaas
Wouldn't the major differentiator be the safety standards?

You can't have a runaway reaction, because you need energy input to the magnet field to get more energy out. Instead of creating the right environment to get a chain reaction started if your control rods end up in the wrong place. Drop the magnet field and it all collapses.

Even if you lose control of it with the magnet field on the quantity is limited, tokamaks can only sustain bursts before going unstable. Wendelstein like designs would also be limited by the quantity contained.

If everything goes completely wrong you simply end up with a dirty bomb from the neutron bombarded core material and an initial burst of radiation. Sure not amazing but not a meltdown releasing vast quantities of heavy radioactive decay materials which can leach into the environment. Remember, fission is messy, it's not a chemical reaction where A+B = C. You get a spread of materials and energies, as seen by the Z number here. [0]

Essentially, you can at any point do an unsafe abort which might damage something or if everything aligns it's no more than a dirty bomb, but you will never lose control. Your Swiss cheese model needs to have far fewer and simpler layers compared to fission, vastly bringing at least those costs down.

I'm still betting on renewables for the near future, but my guess is at least harnessing fusion will have a place for projects with extremely specific goals in the 50-100 year timescale.

[0]: https://upload.wikimedia.org/wikipedia/commons/thumb/6/68/Th...

pfdietz
Fusion will still require a containment building because of tritium and because of the pressure from volatilized cryogenic coolants. The building will also require very strict control of tritium escape in normal operation. Remember, a 1 DW(e) DT reactor will burn enough tritium in one year to contaminate 2 months total flow of the Mississippi river above the legal limit for drinking water.

Fusion will also require highly reliable equipement, just like fission. Not because of safety, but because the fusion reactor will be complicated and very difficult to repair. The reactor itself, even the magnets, will be irradiated and activated beyond the point where hands on maintenance could be performed.

entropicdrifter
Fusion will also be pretty much mandatory for deep space exploration and space colony ships, if we ever get that far
pfdietz
No, it won't. It is inferior to fission, solar, and beamed power.
jjk166
We can make fission plants that are also immune to run away reactions. Even with old designs, you have to do something really stupid like have nightshift take out all your control rods to get a run away reaction.

While the fusion reaction itself isn't very dangerous, the magnetic coils in a fusion reactor can potentially quench, causing them to explode, which because of their position will throw radioactive debris from the irradiated reactor vessel all over the place, as well as your tritium breeding blanket which will be highly flammable, toxic, and a bit radioactive. Worse, you can't make the magnets passively-safe.

Then there are the standard issues like tritium release. And you have nuclear proliferation concerns as a fusion reactor is great at making plutonium by just doping the tritium breeding blanket with some natural uranium. In fact, the first "fusion" reactors will probably do this anyways as they need to produce more tritium to get more reactors online and because this dramatically increases power output - so you get all the fun of dealing with fission products too.

I would be willing to bet complying with the safety standards for fusion will in fact be more expensive than for fission. Yes the general population doesn't have the same irrational fear of fusion that it has of fission, but once people start seriously proposing to put these in people's backyards that will likely change.

SiempreViernes
Its amazing how cutting emission by regulation is completely left out of the list of options, somehow spending infinite money is seen as easier than getting congress to act...

Anyway, I let Wellerstein reply to this:

"""The Manhattan Project was an unusual, somewhat dubious enterprise that had massive, world-affecting consequences. Ignoring that not only misunderstands the Manhattan Project, it misunderstands what happens when you pour essentially unlimited resources into a given field — which actually is the primary goal of those who use this metaphor.

The problem is, the Manhattan Project “worked,” if by “worked” you mean, “produced atomic bombs for use in the Pacific theatre during World War II.” It almost didn’t work — there are plenty of reasons to believe that the war would have been over fairly soon with or without the bombs (the main historical question is not whether it would soon end, but on what terms and at what costs)."""

http://blog.nuclearsecrecy.com/2012/04/02/do-we-want-another...

kenneth
It's widely believed that the use of the bombs in WWII as a practical demonstration of the technology is what lead to there not being a WWIII and generally a period of (granted, uneasy) world stability throughout the cold war. Thanks to the bomb's use at the end of an almost-finished conflict, everyone was too afraid of the destruction to turn the cold war hot. Without it, the cold war would have turned hot and a lot more nukes would have been used. Who knows what the world would look like today without those two bombs.
pasabagi
I think the USSR was typically very keen to avoid a war for obvious reasons: they had a much smaller economy, exhausted population, significantly smaller military and massively smaller industrial base than the West.

America was more keen, but the logistics of actually invading the USSR would make any war essentially unwinnable.

Maybe if the nukes didn't exist, the USSR would have annexed western Berlin, but I don't really know how they would have managed more than that, even if they had wanted to.

I also don't think nuclear weapons would have prevented a war if the USSR was more aggressive or more close to the USA in military power.

SiempreViernes
See wikipedia's list of common misconceptions for a demonstration of the explanatory power of things that are widely believed. Nuclear peace is a theory that find limited support for it's more conservative claims: as the single basis for the "long peace"* it is plainly lacking.

*So called because intra-state conflict outside of NATO doesn't count.

ahelwer
Love too incinerate 150,000 civilians instead of some random atoll with media floating in a boat a few miles away

This is just one of many lacklustre attempts at justifying a hideous war crime. From Eisenhower:

"I was against it on two counts. First, the Japanese were ready to surrender, and it wasn't necessary to hit them with that awful thing. Second, I hated to see our country be the first to use such a weapon."

free_rms
Cutting emissions by regulation is a continually losing battle.

You can't tell people to live a lower-quality life and expect to win elections, and you'll have the combined lobbyists of a lot of different interests against you.

It's actually more tractable to invent fusion than to try and win that battle long-term -- at least it's theoretically possible to make fusion work. And heck, if we could put some $ in pockets while doing it, that's something that could pass!

pfdietz
The Clean Air Act is a clear refutation of your assertion. Benefits there exceeded costs by a factor of about 40.

Fixing market failures increases economic wellbeing.

SiempreViernes
The established solution is you don't tell them right out, you just make it worse for most while ensuring there are a few success stories to distract with. See for instance: war on drugs, war on terror et. al.
free_rms
Yeah, but those horrors made people rich. Cutting emissions makes nobody rich.

Developing fusion, carbon recapture schemes, we need to be thinking in terms of boondoggles that get the job done.

Lammy
> Are we going to wait until the sea level rises 20 feet and then say, geez, compared to the costs this imposed, fusion would have been easy?

Well, yeah, the US spent the last 50 years (e.g. "WTF Happened In 1971?"[0]) widening the income gap and doing everything possible to keep their "undesirable" ethnic groups as poor as possible. When the bottom falls out, the only people left standing will be the people who would have been able to use the nice water fountain back when America was "Great", and anyone suffering will get individual blame for their lack of individual bootstraps.

e: In case I was unclear, I think this is a bad thing :)

[0]: https://wtfhappenedin1971.com/, but I would ask "WTF Happened in 1968?" instead.

pfdietz
Fission was a fundamentally easier problem than fusion. The equivalent of ignition was achieved in 1942 after one year of effort.
logicchains
>God I wish we could Manhattan Project this shit.

Interesting point of reference: the Manhattan project cost around around $25 billion in today's dollars. The US government spent at least $6 trillion on the coronavirus response, which could buy 200 Manhattan Projects. Coronavirus will kill around a million people this year at most; air pollution kills around five million per year (and sea level rises could kill a lot more).

IanCal
The US medical system wastes enough each year ($950B) to start an LHC sized project (~$10B), fully funded, in each US state every year and have enough left over to fully fund three new Apollo scale set of missions ($150B). You can't recover all that, but still, it's hard to picture just how big some of these figures are until you compare to other large costs.
voodootrucker
That number is shocking. I'd love to know details. Can you provide a source please?
rweir
Just the US value from https://en.wikipedia.org/wiki/List_of_countries_by_total_hea... vs #2 (Switzerland) is $US800 000 000 000 for all US residents in extra spending.
marcusverus
I'm confused by these data.

It's common knowledge that the US spends much more per capita on Healthcare, however the commonly offered explanation for this is that the private healthcare system in the US is less efficient than the public systems in Europe. But the graph in the provided link shows that US costs are split evenly between private spending and public spending.

This is confusing because the private system in the US covers twice as many people as the public system. Per the US Census Bureau: "in 2018, private health insurance coverage continued to be more prevalent than public coverage, covering 67.3 percent of the population and 34.4 percent of the population, respectively."[0] If the provided data are correct, this would indicate that US private spending is nearly twice as efficient as public spending.

What am I missing?

[0]https://www.census.gov/library/publications/2019/demo/p60-26...

rendang
The gov't portion includes basically everyone over 65 via Medicare, who have a disproportionate share of healthcare needs.
entropicdrifter
The current laws restrict the government healthcare programs from negotiating on e.g. drug prices, so the manufacturers name whatever absurd prices they want and the US Gov just pays it. Just another corrupt government giveaway to the private sector.
IanCal
It's reviewed occasionally, here's a few links

This was the original article I saw when it was $700B: https://www.theatlantic.com/health/archive/2012/09/how-the-u...

More recent one, I thought it was $950B but this puts it at $760-935B. The potential savings are lower but still in the low hundreds of billions.

https://jamanetwork.com/journals/jama/fullarticle/2752664

I originally started thinking about "how do we understand large numbers" when I saw the article as I think I had roughly the same emotional reaction as I would have done if the number was $70B. Most "big number" comparisons go to things like "dollar bills up to the moon" or "swimming pool full of X" which only gets across "this is a big number". I found comparing it to other enormous projects was hard even as if you take out the US contribution to the LHC you don't move the needle, so you need to then cover all countries costs, then the full project budget for all years and you're still left with almost the entire figure left.

Seanambers
Interestingly enough, the most expensive program was The B-29 bomber program, which cost 50% more than the Manhattan project.

Then one B-29 had an emergency landing in Sovjet and the soviets reversed engineered it into the TU-4. Tu-94 which is still flying is a newer scaled up version of this.

It's amazing how much of the innovation the U.S did in the 1940s ended up in others hands(the bomb, B-29). The world would probably be very different if it hadn't happened.

wil421
The physicists knew an atomic bomb was possible the US just did it fist. I am sure secrets got out that helped the Soviets create one but I think they would've created one regardless.
yostrovs
History says that that's not true and the Soviets relied on extensive networks of spies to get tech secrets, be it the bomb or so many other military projects.
lenkite
The US copied a lot from Germany too. https://www.businessinsider.com/6-things-us-stole-from-germa...

Jets and Rockets were built by the Germans first.

https://www.bbc.com/future/article/20160201-the-wwii-flying-...

01100011
Aren't you implying, intentionally or not, that a "Manhattan Project" level of expenditure, $25 billion, is enough to make meaningful progress towards commercial fusion energy production? I don't think that is a given.
IanCal
That's roughly the total cost of ITER.
tuatoru
According to David Edgerton's The Shock of the Old, Brigadier-General Leslie Groves had previously overseen the construction of several munitions plants costing much more than the entire cost of the Manhattan Engineering District project.

1. Chapter 8, "Invention", p198 in my paperback edition.

xyzzyz
The implication is rather that we’ve grown much more inept when it comes to getting things done.
ars
Or because all the low hanging fruit is plucked.
throwaway0a5e
Because there isn't an existential war going on forcing people to listen to the people who want to be economically efficient.
xyzzyz
Yeah it’s not like we’re in any kind of emergency that required reorganizing the whole society and economy, or anything like that.
mytailorisrich
A lot of the Manhattan Project's spending was to scale the processes to industrial level in order to produce what was necessary to build bombs.

The situation is quite different with nuclear fusion.

Aeronwen
To be fair, it did scale for fusion bombs.
adrianN
Things sure were cheap back then. ITER alone is expected to cost at least 22 billion Euros.
inglor_cz
In my opinion, the main reason for success of the Manhattan Project wasn't the budget, but getting people such as Feynman, Fermi, Teller, Oppenheimer, Bohr, Szilard and Wheeler to work on the project together with a sense of urgency.

25 billion USD buys a lot of necessary stuff, but one Feynman doing his best to crack a secret of nature is priceless.

bwanab
That budget was essential. A hundred Feymans would have been useless without those thousands of engineers and workers who built and operated the plants Kringle Washington and Tennessee that produced fissionable enough fissionable material.
raverbashing
Before the 10x programmers there were 10x physicists and the Manhattan project had a lot of those

And as opposed to the current advertisement websites with auxiliary functions, I believe they had a more physics centered role

lambdatronics
As a technical answer: this is about the federal program, and SPARC isn't part of it, while ITER is.

More practically, Commonwealth & other private fusion efforts have been advocating for (A) federal funds to be allocated to solving the thorny nuclear materials science issues common to (essentially) all fusion schemes (B) a NASA-COTS-inspired cost-share approach to building the eventual pilot plant. (Presumably the industry players would like to get federal support for building their pilot plants (like ARC), much the way SpaceX got support for Falcon 9 / Crew Dragon development.)

This plan reflects (A) for sure, and a step in the direction of (B). I was involved in the early stages of the community input to the plan. I think there's openness to increased partnership with industry like this.

sbierwagen
The article image is of ARC, the predecessor to SPARC.
baking
Well, SPARC is a mini version of ARC. Smaller and without a blanket.
cbm-vic-20
Kendall Square still got it!
Lammy
I am pro-nuclear, and I think it would be a mistake to assume this article is also pro-nuclear. Heck, the very first six words ("U.S. fusion scientists, notorious for squabbling") prime a reader to see those hardworking people as bickering nerds working on fleeting, individual, theoretical interests.

I sincerely doubt we will see any uranium-based energy technology ascend to dominance/ubiquity while over half of Earth's known uranium deposits are in the Afghanistan/Kazakhstan/Ukraine region alone. Nobody would want to buy crude (priced exclusively in USD in most markets) if nuclear were widespread. We might have to lay off a few Stuxnet malware developers then too. Takin' their jobs :p

[0]: https://en.wikipedia.org/wiki/List_of_countries_by_uranium_p... [1]: https://en.wikipedia.org/wiki/List_of_countries_by_uranium_r...

halfdan
You are talking about fission, not fusion.

Nuclear plants are using radioactive sources like uranium to generate energy. Fusion tech would use hydrogen and fuse it to helium.

Lammy
Yep, and it is not just feasible but easy to build fission plants right now and stop using greenhouse-gas emitters entirely, but we won't, because Reasons. Our collective focus is being distracted from that working, clean, but politically-disadvantageous tech to this non-functional speculative future-tech that the author simultaneously insults.
jasonwatkinspdx
People love to post comments like this on every thread where nuclear comes up, but it really distorts the reality of the situation.

Investment in nuclear has essentially evaporated. This is because fission plants take billions of dollars and around a decade to stand up. If you go through the numbers the ROI looks pretty ugly. Meanwhile you can look at the trend over time in levelized energy costs and storage costs, and can see that we're very near the thresholds for simply doing it all with renewables plus storage. All together this makes it clear to any investor doing the most basic of diligence that fission is a risky bet. Even if you waved a magic wand and eliminated any form of political opposition, that doesn't change this less than favorable cost picture.

Lammy
> Even if you waved a magic wand and eliminated any form of political opposition, that doesn't change this less than favorable cost picture.

The cost is the manifestation of the political opposition.

jasonwatkinspdx
No, it is not. It's intrinsic to the technology. You see the exact same unpleasant numbers in entirely state funded fission, including everything China is currently building. CCP certainly isn't paying the same costs out of "politics."

I want to be clear: I'm generally pro nuclear. I'm just exhausted by the smug "scared idiots and politics ruins fission" when the situation is considerably more complex.

czzr
Fusion is not a uranium based energy technology.
baking
Because SPARC is already happening. This is planning for research in areas that the next reactor will need including a neutron source to test materials and a blanket test facility.

See Bob Mumgaard's slides from last year's annual meeting of Fusion Power Associates where he outlines the research for technologies needed for by all the approaches to fusion power.

http://www.firefusionpower.org/FPA19_Speed_Mumgaard_CFS.pdf

Quote from the last slide: "It would be a travesty for somebody to have a concept that works and have fusion stall because we, CHOSE not to prioritize the parts that help everybody."

This is where government funded research helps the emerging fusion power industry.

After watching Zach Hartwig's youtube video [1] which culminates in talking through the ARC/SPARC approach to building more compact tokamaks (that don't require epic levels of global political collaboration, multi-decade planning and financing like ITER) I've been seriously considering a career change just to try and get involved! (There's a more focussed video on the Commonwealth Fusion Systems approach here [2])

As a physicist, turned developer, turned tech manager based in the UK I'm not quite sure what an opportunity looks like, and whether the right approach is to bash the plasma physics books, or wait for a more tech-orientated role to crop up.

I'm also really interested to know how these startup-esque companies are all going to handle their intellectual property now they're private enterprises - are their individual breakthroughs all going to be kept deeply secret (and vanish if/when most of them eventually fail) or are they all going to be frantically cross-licensing their discoveries so that in aggregate we don't lose out of the benefits of collaboration. According to A Piece of the Sun (by Daniel Clery) the early days of fusion research were hampered by international secrecy - things really started moving when researchers persuaded their governments to open up and let them work across borders.

[1] https://www.youtube.com/watch?v=L0KuAx1COEk [2] https://www.youtube.com/watch?v=KkpqA8yG9T4

pierre
In the uk you have tokamak energy that is using the same aproach than arc (and they seems to be hiring).

https://www.tokamakenergy.co.uk/

Retric
Building an ITER sized device is not that expensive, doing serious R&D is what’s so expensive. Their looking into multiple lithium blanket designs for example and just collecting a serious amount of data. An actual power plant doesn’t need that many sensors or to operate across such a wide range of conditions.
sgt101
That's kinda not what people like Whyte at MIT say. They make the case that the scale of a complex device is the cause of an exponential increase in costs - both capital and operational. For example removing delicate low level radioactive magnates for servicing is easy if they weigh a kilo, a pain if they weigh 200 kilos, a big undertaking if they weigh 1000k and harder and harder and harder the larger they get.

You can see the cost increase with fission reactors - a full on big reactor like sizewell C is slated at £8bn.

Retric
If it’s radioactive enough to be a safety hazard then you need remote handling equipment either way. Further, we aren’t talking 1/200th the size, a ~1GW reactor can only be so small because the amount of heat being transferred.

That said, ITER is a very old design based on outdated limitations. But, again the goal is research not low cost power generation, a stable design is more important to them than an efficient design because the secondary equipment is so critical.

aaronblohowiak
Time is more important than cost wrt fission development and global warming
Retric
Based on data we have, fusion seems unlikely to be economically viable for a long time even if it’s technically viable. Various advancements like better superconductors might change the situation, but without that there seems to be little hurry needed.

At least after talking with people in the field the reactor design seems like the least important problem.

willis936
I work as an engineer on a university stellarator. I’m not close to plasma physics, which is fine since I’m good at what I do and what I do (data acquisition) is necessary. There are lots of fields that are not plasma physics that are needed to have actual experiments made and operated.

If you want to break into research: hit the books yesterday. You’ll need to be able to speak the lingo and know what machines around the world are doing. This might be difficult outside of an academic setting, but a life in academia is a tough pill to swallow. I’m not the right person to give you a list of literature, but “Plasma Physics and Fusion Energy” by Friedberg is considered the go-to book in my group.

Also, regardless of whether or not you make a big life change, I highly recommend that you read “The Future of Fusion Energy” by Parisi and Ball. It is just the right level of technical to give understanding to the problem but not so technical that someone without a plasma physics background will be lost.

Another excellent talk for those interested is MIT's Pathway to Fusion Energy (IAP 2017) - Zach Hartwig.

https://www.youtube.com/watch?v=L0KuAx1COEk

He goes into detail about SPARC as well and why a higher magnetic field using HTS superconductors enables performance that can otherwise be obtained by greater size as ITER is trying.

My layman's understanding is that recently available (~last 5 years) industrial scale processes to produce rebco tape[1] is the specific advance in superconductor tech that's specifically enabling higher tesla magnetic field strengths from significantly smaller and lighter and easier to manage magnets, so you can get a system that's "powerful enough" to run net posititve at a size that's small enough to be built by a few universities rather than a few dozen nations (i.e. ITER), so the complexity of the engineering project drops from "unimaginable" to "just very high".

1 - https://www.fusionenergybase.com/concept/rebco-high-temperat...

2 - really great talk from a few years ago about this from MIT's Plasma Science Fusion Centre: https://www.youtube.com/watch?v=L0KuAx1COEk (really, if you like this stuff, give the talk a watch. It's great.)

ChuckMcM
Better link on ReBCO (in my opinion) https://nationalmaglab.org/magnet-development/applied-superc...

They were specifically looking at the tapes ability to function in high magnetic environments such as a tokamak type reactor.

rkaplan
This is the correct answer. A key reason Rebco is so much better than older alternatives is that it can be cooled to superconductivity using only liquid nitrogen (77K), as opposed to liquid helium, which is much harder to work with.
foobarian
Nit: ultimately the new magnets need to be stronger for the same volume no matter how easy the cooling is to work with. That part is just a nice bonus.
Already__Taken
2 - skip to ~2:30 for the speaker, whose mic'd and the sound greatly improves.

Good job recording MIT.

Nimitz14
Awesome talk thank you for sharing.
gorkish
Yep; the key technology that took magnetic confinement fusion from 'ITER will probably work' to 'Maybe we should just go ahead and skip ITER' is rebco tape.

The problem is that all known superconducting materials known will lose their ability to superconduct when exposed to a sufficiently strong magnetic field. The large field strengths induce eddy currents in the material which disrupt the propagation of the cooper pairs in its superconducting mode. The current sufficient to self-induce this field is called the critical current.

Layered rebco tape appears to shield against this effect or otherwise trap the eddy currents in a way that superconductivity is preserved even in the presence of extremely strong fields. The critical current in REBCO tape is enormously higher than in previously known materials or winding configurations.

Obviously the bigger the reactor volume is, the smaller the magnetic field needed to steer and confine the plasma within it can be. So back when they were designing ITER, engineers figured out the strongest magnet they could make, then they designed the reactor to be small enough (lol) that said magnet could still sustain confinement.

However now that we have stronger magnets we can make reactors smaller. This is even something of an gross understatement as the relationship is cubic. For a doubling in field strength, the reactor can be 8 times smaller. That effect is very meaningful when considering that you are essentially talking about shrinking something the size of ITER's 28m main reaction vessel to something that might fit into a garage.

I'm not really any kind of expert on this, so please treat this explanation as very simplistic.

I have not yet personally seen anything about this new lattice confinement modality that seems to give me anywhere near the same level of confidence that they will see viable applications compared to the magnetic confinement approach. (NIF already stood down their tries at laser inertial confinement) Maybe someone has some good insight on whether or not this is all still speculative fanfare or if researchers are finding real meat.

tgsovlerkhgsel
Would it be feasible to upgrade ITER into a much more powerful plant with the new magnets, or are they basically spending another 15 years building a huge thing that is already obsolete?
Mvandenbergh
It's probably not feasible to upgrade it but apart from the magnets a lot of problems being solved for ITER (especially materials, tritium handling, and remote operations) will be useful for any Tokamak and indeed for any magnetic confinement fusion device.
jasonwatkinspdx
ITER is not obsolete even if better magnet designs are now possible. It's an incredibly huge and complex project with many critical details. It's literally spawned 10's of thousands of research papers. It's a pathfinding project with far more value than just this one aspect.
There's some discussion about this in this[1] presentation which also mentions the SPARC reactor. My main takeaway is basically yes, high-temp superconductors got "mainstream" very quickly.

I'd recommend watching the whole thing, I found it quite interesting.

[1]: https://youtu.be/L0KuAx1COEk?t=2929

willis936
It’s important to keep in mind that MIT is working hard to monetize HTS coil production. There are some unseen hush hush politics at play here.
It’s predicted to be able to have a Q>1.

This lecture was enlightening: https://youtu.be/L0KuAx1COEk

Someone below mentioned the following link, in which they do a sharp comparison of fusion technologies. I am by no means an expert, but after watching that link, it appears to me that such solutions are probably unproven science: it took over 50 years to get anywhere near a Q-factor of 1 (energy in = energy out), with hundreds of technologies screened, tested and scrapped.

    https://www.youtube.com/watch?v=L0KuAx1COEk
At this point I've got a lot more hope in the MIT/Commonwealth Fusion Systems approach with REBCO magnets: https://www.youtube.com/watch?v=L0KuAx1COEk

At this point it looks like ITER is hampered by it's relatively old supeconductor technology (ultra low temp/moderate field strength traditional magnets vs high temp/high field REBCO magnets).

Mvandenbergh
Luckily, since ITER and SPARC are being built with the same aspect ratio, all the learning about plasma control, materials, cooling, tritium, remote handling, etc. is fully transferable.

The tritium extraction and processing is a whole separate multi-story building full of first-of-a-kind equipment which will be 1:1 transferable to any breeding fusion reactor.

The work that ITER and IFMIF will be doing on material lifetime and handling under heavy neutron bombardment - a really substantial engineering problem - will be fully transferable.

The work on first-wall material which has to handle the neutron flux, very high thermal loads, and not poison the plasma when traces of it come off is also fully transferable.

Basically everything that's really new about ITER except for the size will work the same way on an HTS based machine.

I'd say about 2/3 for the science done at ITER would need to be done for any D-T fusion device, another 1/6 applies to all similarly configured tokamaks (i.e. it's less less relevant for stellarators or spherical tokamaks), and 1/6 is ITER specific (high estimate TBH).

If things run according to schedule (obviously questionable) then in 2025/2026 ITER will have first plasma and CFS will be on schedule to start building SPARC. CFS is being very clever in doing all their magnet design work first - investors are funding it because even if they don't get either SPARC or ARC funded and built, they will at least have some very useful IP on large HTS magnets which is bound to be worth something.

sam
ITER and Commonwealth can (and in my opinion should) be seen as complimentary endeavors.

ITER has been designed with relatively conservative magnet technology and will very likely provide the physics results that need to be understood in order for fusion power to become a reality. This includes experimental tests of the physics of plasmas where the heating is dominated by high energy alpha particles rather than external heating. This is a regime that's not yet been studied in a laboratory and there is important research to be done there.

Commonwealth is pushing the envelope of high temperature superconductor magnet technology and is relatively high risk compared to ITER's magnets (and this is a good thing). Lots of ITER technology will be useful to Commonwealth even before ITER turns on. For example decisions about which low activation steels and the huge amount of physics work that's already gone into planning for ITER.

I think the most likely outcome is that both accomplish their goals and contribute to making commercially viable fusion energy a reality in the future.

There's a good talk here about why ITER is so large: https://www.youtube.com/watch?v=L0KuAx1COEk

The idea is essentially that to get the parameters needed to make net energy with tokamaks, you need either very strong magnets or a large device. At the time of ITER's design, they used the strongest magnets they could find and then made the thing big enough to get the energy gain they wanted.

The speaker of this talk argues that it's size that stalled progress in tokamaks, since they'd become so big that building them became a massive, multinational project.

jfarlow
^ That is a _fantastic_ talk for someone who know's some physics get a quick grasp of the state of the field, the different approaches being taken from a set of first principles, and how to evaluate them.
xixixao
Also check out this UK company which is instead going down the path of using stronger magnets: https://www.youtube.com/watch?v=hWYnbYsp3i8
pengaru
I didn't watch the talk, maybe it's the same one, but I recall watching a talk about Tokomaks that said thanks to the development of high-temperature superconducting wire ITER is already an obsolete design.
andsens
Awesome talk. Thank you for the link!
fabian2k
I wonder how much the possible magnet strength affects the design of a tokamak. There are very clear limits on the field strength you can achieve with classical superconductors, and I know e.g. in Nuclear Magnetic Resonance those limits had been almost hit maybe a decade ago or so. But very recently spectrometers based on new high-temperature superconductors have been delivered, so the technology seems to be far enough for actual production use now. I'm not sure how big the possible increase in field strength will be. Right now it's 23.5 Tesla for the largest NMR spectrometer with conventional superconductors compared to 28 Tesla for the new ones with high-temperature superconductors (actually it's a hybrid with high-temperature superconductors on the inside, and conventional ones on the outside), but I suspect there is more room with the new ones for higher fields.

It would be interesting whether the availability of better superconductors would change the design of a fusion reactor much, and allow significantly smaller ones.

petschge
Yes that has a big impact. The quality of a tokamak (as meassured by the triple product density, temperature, and confinement time) goes up like B^3 (IF I remember correctly, I do plasma physics but not fusion stuff) and the fussion power goes up like B^4 or something like that. So larger magnetic fields help a lot. But back when ITER was designed we did not have such strong superconductors yet.

PS: Google found DOI 10.1088/0029-5515/56/6/066003 but I didn't read it carefully.

DubiousPusher
Is there a successor to iter already being worked out on paper that takes into account new developments?
petschge
There is things such as SPARC by Commonwealth Fusion Systems (CFS) using rare-earth barium copper oxide (REBCO) superconductors. Not quite the scale of ITER, but it should give us some first experience working with that material. If that works out the next step would be ARC [1].

[1] https://en.wikipedia.org/wiki/ARC_fusion_reactor

twic
Yes - the sequence is ITER, DEMO, then PROTO:

https://en.wikipedia.org/wiki/DEMOnstration_Power_Station

https://en.wikipedia.org/wiki/PROTO_(fusion_reactor)

wcarss
Yes, the video above is basically about this, and is really worth watching -- it's a fantastic talk.

I'm pretty sure that Commonwealth Fusion Systems[0] is the entity affiliated with MIT that has been doing work to prove out the recently available higher magnetic field strength superconducting materials and apply them to tokamak construction to bring size down dramatically. They had a bunch of press in 2018/2019 when they first got underway[1], and it looks like they've received a lot more investment over the last few years and likely made quite some progress since then[2].

0 - https://cfs.energy/ 1 - https://www.bostonglobe.com/opinion/2018/03/09/new-approach-... (op-ed in the Boston Globe by a Vice President at MIT) 2 - https://cfs.energy/press/

maccam94
Cambridge Fusion Systems[1] is a private company spun out of MIT that is building a proof-of-concept reactor based on these new magnets within the next 5 years.

Breakthrough in Nuclear Fusion? - Prof. Dennis Whyte (2016) - https://www.youtube.com/watch?v=KkpqA8yG9T4

Timeline (in case you want to skip over some parts):

  00:01:00 - introducing Dennis Whyte, MIT department head for nuclear science
  00:04:24 - presentation starts
  00:06:00 - identifies breakthrough with REBCO magnets
  00:07:25 - explains deuterium-tritium fusion
  00:12:30 - basic metrics for reactor performance
  00:17:15 - energy output of other previous fusion experiments
  00:19:00 - examines ITER and the problems of its approach
  00:22:00 - problems solved by high energy magnetic fields
  00:28:15 - full scale reactor concept, teardown of REBCO magnets
  00:37:00 - design limits and margins
  00:39:00 - fixes plasma instabilities found in weaker magnetic chambers
  00:40:00 - maintainability, lifespan, component replacement
  00:45:00 - solution to neutron damage and energy capture
  00:50:30 - cost and profitability
  00:54:00 - full graph of field strength vs reactor scale (and thus funding requirements)
  01:01:50 - Q&A
  01:30:00 - question about the biggest risks
He gave another talk in 2019 with more numbers and even more confidence: https://www.youtube.com/watch?v=rY6U4wB-oYM

1: https://cfs.energy/technology

pfdietz
And then you go to the arxiv paper for ARC and learn: the power density is 40x worse than a PWR primary reactor vessel, and their projected cost is $29/W(e) (vs. < $1/W(e) for PV). Also, the vacuum vessel likely wouldn't survive a disruption (although maybe they've fixed that in the years since).

Compact high field tokamaks have better power density that ITER or DEMO would, but they still are very inferior to fission reactors. And fission reactors are far out of the running economically.

https://youtu.be/L0KuAx1COEk

MIT's Pathway to Fusion Energy - Zach Hartwig

tl;dr: it's a matter of funding

pfdietz
ARC, the design that would require 40% of the world's annual production of beryllium to make a single 500 MW(th) reactor.
kaibee
> Total world reserves of beryllium ore are greater than 400,000 tonnes.[27]

https://en.wikipedia.org/wiki/Beryllium

Seems like there's just not enough demand yet.

pfdietz
Total world estimated Be resource would make ARC reactors capable of supplying just 1% of current world primary energy demand (using the USGS estimate of 100,000 tonnes.)
Aug 06, 2019 · evdev on A Commercial Path to Fusion
For a breakdown of the reasoning behind the project, if you haven't already seen it:

https://www.youtube.com/watch?v=L0KuAx1COEk

TecoAndJix
That video was super informative! Thank you for sharing it
rhcom2
For a layman this was incredibly interesting. The speaker explains the concepts very well.
It's questionable. ITER's design comes from the late 1990s and early 2000s.

Hight Temperature Superconductors (HTS) have changed the game. HTS tape has only been available for about a decade.

The cube of magnetic field is proportional to the energy gain in a Tokomak. See this video at at 46 minutes to get the equation, watch more to understand why people are now doing this.

https://www.youtube.com/watch?v=L0KuAx1COEk

Tokomak Energy and Commonwealth Fusion Systems among others are looking at smaller reactors that use High Temperature Superconductors.

Also have a look at Helion Energy.

Also note that the Chinese are starting to put serious money into fusion research.

https://www.reuters.com/article/us-china-nuclearpower-fusion...

piva00
Reading this article one thing that pops in my mind is: we have spent more money collectively to fund the LHC in CERN as we have funded ITER.

As much as extremely good science has came out of this experiment it boggles my mind that we have spent less in the search for the next breakthrough in energy generation, something that ALWAYS has catapulted technology and development of humanity.

Why?

pfdietz
The fusion effort is based on a set of assumptions that might have seemed reasonable in the 1950s when the effort got started, but are no longer realistic.

Fusion assumes the problem with nuclear power is that uranium is scarce, so the cost of nuclear energy would be dominated by fuel cost. In such a scenario, where reactors themselves are cheap, it makes sense to make a more complex expensive reactor to save on fuel. This was also the motivation for breeder reactors.

But this isn't how it worked out.

Fuel is a small part of the cost of nuclear fission power. The cost of building and maintaining the power plants, and disposing of them at the ends of their lives, turned out to dominate.

In that scenario, making larger, more complex, more expensive reactors just so one can burn deuterium and lithium is totally bass-ackwards.

The collapse of the fission breeder program should have been a sign that fusion wasn't going to work either. They were both based on the same incorrect idea of how things were going to go.

petschge
Except that fusion reactor have a bunch of advantages over all fission designs, including breeder and molten core Thorium, that you conveniently ignore.

The big one is: ramp up time is measured in minutes not days. This is a perfect addition to a grid that gets a large fraction of it's power from (somewhat) variable renewable energy.

The next big one is: There is no proliferation risk. No spent fuel that contains isotopes suitable for building fission bombs. And now legitimate reason for uranium enrichment to process your own fresh fuel. In other words there is no reason not to give this technology to North Korea or Iran.

The third important one: No radioactive waste that needs to be contained long term. The main "ash" is helium-4 which is not radioactive. The neutron flux will activate parts of the reactor vessel, but the halflifes are generally below a century. General rule of thumb is that things need to be contained 10 halflifes. Humanity has demonstrated successfully that we can build buildings that last 1000 years. This is a big contrast to the waste from fission plants that needs to be contained at least 100000 years, longer than we have had buildings.

pfdietz
I ignore these putative advantages because they are of minor importance, compared to the major downside of cost. If fusion is too expensive, all those other things do not matter.
ikeyany
Having worked on that tokomak, I can confirm that the Chinese are not playing around when it comes to funding long-term science initiatives. The US should be doing some serious soul searching about its priorities...where is the collective national vision of tomorrow?
Progress on the triple product :

https://en.wikipedia.org/wiki/Lawson_criterion

has gone up faster than Moore's Law :

https://i.imgur.com/BN0pz.png

The problem is that the next device costs a lot more because it has to be much bigger, that is unless you have much stronger magnetic fields. The cube of magnetic field is proportional to the energy gain in a Tokomak. See this video at at 46 minutes to get the equation, watch more to understand why people are now doing this.

https://www.youtube.com/watch?v=L0KuAx1COEk

Tokomak Energy and Commonwealth Fusion Systems among others are looking at smaller reactors that use High Temperature Superconductors.

My problem with this article is the focus on the "startup" mythology of moving fast and breaking things. Break a Coulomb barrier, first, and then come talk to us.

I really liked https://www.youtube.com/watch?v=L0KuAx1COEk for a discussion of how to evaluate and understand fusion claims, as well as a discussion of the high-field REBCO tapes that seem poised to enable the ARC/SPARC reactors out of MIT. Another video I like is https://www.youtube.com/watch?v=SMxOvuSMAug , featuring Steven Cowley.

In short, newly commercially available high temperature superconductors in mass quantities seem poised to give us at least a doubling of available magnetic field strength, and all the figure of merit that improve only linearly with size improve to the 2nd, 3rd, or 4th power with magnetic field strength. This is what could lead to break-even before ITER, not the mythology of American entrepreneurial moxie.

In my opinion, the article author knows whom he's flattering.

There are a number of interesting companies looking at fusion.

High Temperature Superconductors change what you can do for Tokomaks.

In the US Commonwealth Fusion Systems are exploring these paths:

https://en.wikipedia.org/wiki/Commonwealth_Fusion_Systems

In the UK Tokomak energy are exploring ideas as well:

https://www.tokamakenergy.co.uk/

This video explains why high temperature super conductors can enhance fusion's prospects:

https://www.youtube.com/watch?v=L0KuAx1COEk&t=3642s

A run down of the various options, from a pro-tokamak perspective:

https://www.youtube.com/watch?v=L0KuAx1COEk

singularity2001
Thank you so much for the great video!

Key takeaway:

Thanks to progress in superconductive magnets, a new reactor type developed by the MIT called SPARC might likely become the first Fusion Reactor to achieve net energy output before 2030, producing 200MW in 1/65th the volume of the ITER design, at a fraction of the costs.

All based on very solid physics with only littly uncertainty remaining. Wow.

[0] https://en.wikipedia.org/wiki/SPARC_(tokamak)

Also: all other designs don't even come close to fulfilling this promise.

"The Helias (Helical Advanced Stellarator) reactor is based on the Wendelstein stellarator line and takes into account the design criteria of a power reactor."

http://epsppd.epfl.ch/Sofia/pdf/P4_192.pdf

Alas, it "just" seems to talk about extending the coil design for a reactor, not the rest. I am guessing most of that would be similar as for other fusion reactors, see for example MIT's Pathway to Fusion Energy:

https://www.youtube.com/watch?v=L0KuAx1COEk

xxgreg
Thanks for the links. Had a bit of a google for Helias. Looks like the Wendelstein team are exploring using something called a "Helium Cooled Pebble Bed Blanket", which was designed for ITER. To me it looks like a closed loop heat exchanger using helium. This would then be fed into a typical steam system.

Though I don't really understand the significance of the "pebbles" in this system.

gmueckl
The pebbles will most likely be made of Lithium because it is a solid/liquid at the operating temperatures of the cooling system and therefore has a high density. It is also an element with a very low atomic mass, which makes the crosssections for interactions with fast neutrons comparably high. So the Lithium will have collisions with the fast neutrons from the D-T-fusion that leave the plasma confinement with most of the energy from the reaction. These will heat up the pebbles due to the energy transfer and from time to time a Lithium-6 atom will catch a neutron. This will make the Lithium core fission into a Helium code amd Tritium core. Tritium is one of the two fuels required for fusion and has a very low natural abundance due to its rather short half life. So breeding it seems to be the best option to obtain it in sufficient quantities.
Agreed — the problem is that, from an energy perspective, it "doesn't break even".

Zach Hartwig of MIT has an excellent video [0] of how to evaluate announcements of nuclear fusion advances. The big problem is breaking even. There are other problem, too: plasma containment, etc.

[0] https://www.youtube.com/watch?v=L0KuAx1COEk

Nov 14, 2018 · 1 points, 0 comments · submitted by nabla9
As there seems to be quite a lot of confusion in this thread about what this is, here's an excellent video giving an overview of the state of the art in fusion energy research that is understandable by a lay audience: https://www.youtube.com/watch?v=L0KuAx1COEk

(somebody posted that video on another recent HN fusion thread)

joosters
Thank you for (re)posting that video, it's an excellent introduction/overview.
I think this talk (https://youtu.be/L0KuAx1COEk) makes a pretty good case for why a project of the scale of SPARC makes sense from an engineering standpoint.
pontifier
Very interesting video...

My answers to the questions in the video are:

Fuel: D-D

Temperature target: 15kev

Confinement: hopefully approaching ideal at small ion counts. (penning traps are very good at trapping particles for long periods of time)

Instabilities: unknown but probable at high ion counts. I know there will be challenges to solve, but hopefully they are not fatal problems.

I believe the first prototype could achieve Q>1

Another excellent talk, about a year later: https://youtu.be/L0KuAx1COEk
> Scale is everything for fusion (plasma).

No. Q is everything in fusion. Scale is one way to improve Q in a Tokamak. The problem with improving Q by increasing scale is that it makes the reactors uneconomical. A reactor the size of ITER cannot ever be economically viable, even was capable of producing massive amounts of electricity.

Luckily, scaling up is not the only way to increase Q. The better way is to use more powerful magnetic fields.

Put more eloquently than I can: https://www.youtube.com/watch?v=L0KuAx1COEk&t=43m47s

infogulch
Wow that's a really great talk, thanks for sharing!
pfdietz
Unfortunately, even with higher magnetic fields, DT fusion is unlikely to ever be practical. That's because the power density of the reactors is inherently limited by wall loading and minimum size considerations from neutron cross sections.

Look at the numbers. The power density of a PWR fission reactor core is 100 MW/m^3. If you consider the volume of the primary reactor vessel instead, it's 20 MW/m^3.

The power density of ITER is 0.05 MW/m^3 (counting gross fusion power). Even if you just include the volume of the plasma, it's 0.6 MW/m^3.

What about higher field concepts like MIT's ARC reactor? If you look at the paper on arxiv where details are given, the power density is 0.5 MW/m^3 -- 40 times worse than a PWR.

The low power density is devastating to the economic case for fusion. Magnetic fusion reactors will be complex, expensive things, with superconducting magnets, complex cooling systems, breeding blankets, heating and control systems. They will be much more expensive per unit mass or volume than a simple PWR reactor vessel. And much of that complex system will need to be periodically replaced due to neutron damage. If the power density is 40x worse they cannot possibly compete.

Yes, (SP)ARC is better than ITER. But ITER is so horribly bad that a reactor can be an order of magnitude better and still not have any real chance of competing.

pas
Agreed. Aneutronic fusion is the end goal and the real prize in the fusion game, and we're very very far from that. Yet with just waiting for it, we'll never get closer.

And of course eventually clean (as in proper reprocessing/recycling) fission energy would be great too, but that again is stalled, largely due to nuclear armament proliferation concerns.

londons_explore
I don't see why the number of cubic meters matters?

If you give me a machine that outputs 50kilowatts, I'll happily give up a cubic meter of my house for it...

pfdietz
Because size (and complexity) directly correlate with cost. So unless fusion can enable cost reduction elsewhere, if the nuclear island is inherently larger, more complex, and hence more expensive than in a fission plant, power from it will be more expensive than from a fission plant. And in that case, why would any utility want one? New and risky (in the sense of having a significant chance of not working as well as hoped) technologies like fusion will be adopted only if they are significantly less expensive than more proven alternatives.

The size and complexity also directly affect reliability. There is more to go wrong in a fusion reactor than in a fission reactor, and repairing anything there will be difficult because hands-on work will be impossible.

tim333
Well, from a 2016 article on ARC they say cost 4 to 5 billion USD, output to the grid 200MW, which is not competitive with existing reactors but that would be the first one producing power built, the designs may improve. (https://www.computerworld.com/article/3028113/sustainable-it...)
My first thought was that maybe this would lower the cost of particle accelerators like the LHC, due to more mass production of superconducting magnets.

The other consideration is that apparently we now have much more powerful, higher temperature superconductors, at least the talk about MIT's current fusion project says so.

https://www.youtube.com/watch?v=L0KuAx1COEk

Not sure if they are cheaper, but since there would be less bulk and no need for liquid helium, that would be my guess.

There is also an excellent presentation from one of the post docs

https://www.youtube.com/watch?v=L0KuAx1COEk

The approach and physics are well established. This seems like the quickest way to break the net power gain barrier with the lowest risk and lowest cost today and will allow individual labs and entrepreneurs to iterate on the implementation and engineering much more rapidly.

Oct 29, 2017 · 2 points, 0 comments · submitted by dmmalam
Didn't read the article yet, but this is relevant to the discussion.

https://youtube.com/watch?v=L0KuAx1COEk

Simple: people in the know realize that this technique still needs a bunch of development.

This is a good talk about the various variables you need to demonstrate in fusion: https://www.youtube.com/watch?v=L0KuAx1COEk

This talk by Zach Hartwig from IAP 2017 "MIT's Pathway to Fusion Energy" is fantastic. Hartwig is an assistant professor in the Nuclear Science & Engineering department at MIT. He presents a straightforward overview of the basic science involved as well as the most promising technologies today.

https://www.youtube.com/watch?v=L0KuAx1COEk

bsder
Probably the only tech video I have watched completely in the last 12 months (I hate video--it's such a slow way to transmit information).

While it clearly is a bit of marketing for his own baby (tokamak with modern superconducting magnets), it has a lot of good technical points.

The big one being that tokamak is the only fusion technology anywhere near being commercially feasible--by several orders of magnitude.

You might allowed to be much more optimistic.

A 50% increase could be much much more significant depending on the parameter optimised. Tokamak magnetic field strength for example has a factor ^4 effect towards net energy.

Have a look at https://www.youtube.com/watch?v=L0KuAx1COEk , as previously discussed here: https://news.ycombinator.com/item?id=14834390 .

Jul 23, 2017 · 129 points, 34 comments · submitted by mozumder
wwarner
Found this opposing pov: http://thebulletin.org/fusion-reactors-not-what-they%E2%80%9...
mcqueenjordan
Summary in text for those of us that cannot watch a video at present?
majjam
tl;dw: the best model is the tokamak, new magnets mean that they can be much smaller (and cheaper) than expected. This is awkward for existing projects (iter).
markvdb
Plus:

* Stellarators like https://en.wikipedia.org/wiki/Wendelstein_7-X are very interesting academically, and the only alternative approaching net energy positive fusion within an order of magnitude.

* The shrinking of the process thanks to HTS magnet technology brings net energy positive fusion within reach of national governments or soon even major institutions.

He was promoting a compact MIT tokamak design called SPARC, a derivative of ARC described below: http://news.mit.edu/2015/small-modular-efficient-fusion-plan...

Geee
Tokamak's output is relative to its size and strength of the magnetic field. Using new off-the-shelf high-temperature superconductors you make make ITER on your kitchen table.
yk
Short answer, MIT discovered unobtanium and now fusion looks pretty good.

Longer answer, the crucial part in a fusion reactor is the magnetic confinement and with the field strength conventional superconductors can manage you need a large reactor. In the last 20 years two things happened, first high temperature super conduction was discovered and someone figured out how to build a compound material from them and stainless steel. The high temperature super conductors solve the problem that there is a critical magnetic field strength and the stainless steel solves the problem that the material has ugly mechanical properties. With that you can use much higher field strength in your fusion reactor and that means much smaller reactor and that means much cheaper experiments. (In another talk the speaker claimed the scale of the experiments drops from large experiment for the entire international community to large experiment for MIT.)

Last time I looked at that project, it looked that the MIT fusion group is competitive with ITER, and it should be mentioned that even if the path forward is high temperature super conductors, then ITER was still the right bet 15 years ago. The thing is 15 years ago you could not bet on everything magically working out and the entire ITER concept is guaranteed to work. The international community did decide that fusion is interesting enough even if the safe path forward is really really expensive.

ibarrac
In the video the researcher claims that they can build a significantly smaller/cheaper tokamak with HTS (high temperature superconductor) materials technology that has only became available in the last 5 years. Even if ITER is built not using HTS, can HTS be later retrofitted into it and therefore improve its performance down the line?
topspin
These are certainly the painfully obvious questions aren't they? Hartwig claimed that HTS can make existing designs either smaller or more powerful, so what about ITER?

And yet it isn't addressed, and it -- somehow -- doesn't occur to anyone in this MIT audience to ask. Even if one wished to argue that ITER is committed to a design and shouldn't be altered at this point it would still useful and compelling to at least compute how much better the ITER reactor might be... but nothing like that happens here.

I imagine that any person endeavouring to earn a place in fusion power research (at least at the university or government level) needs to be careful about questioning ITER design. At the moment ITER is the home of many of the worlds leading fusion power minds and all of the best funded ones, so you'd better have your ducks in a row. The fact that the question isn't directly addressed is probably an indication of just how certain the HTS proponents are about their proposal.

One of the best parts of the talk were the photographs of the unknown alloys ("tokamakium") being deposited on the surfaces of a tokamak plasma chamber. Interesting things.

candiodari
ITER has done heroic design efforts over the past few years. But you'd be disappointed how small the resulting changes were, but they were heroic efforts. Things like feedback systems for plasma containment. So to your question, the answer is no. ITER cannot be retrofitted to use HTS materials. Effectively they cannot change the materials they use, nor can they change the shape of the superconductors. If you can't do that, there's no real point to switching to HTS supply.

The problem with ITER is that it's being half-ass funded. It's only enough funding to build it over 50 years or so. We could spend 3-4x the amount one year and have it built in 2 years instead and we wouldn't be asking these sorts of questions. We would know (that it doesn't work - I'm not a believer. However, I do agree that a massive amount of plasma physics will be learned with it after it fails to Q>1).

ChuckMcM
Of course if you can build a 200MW plant (ARC) for $50B that has an operating cost that allows for it to pay for itself in 10 years you'll have companies like Apple or Facebook building them.
jjaredsimpson
That's $2.85 per kWh. Seems impractical
ChuckMcM
Well presumably if you could build one, you could build fifty for better economics. I agree with Dr. Hartwig that once you know you can build even one, everything changes. I hope I live to see that day.
shoo
i attended a talk on energy use at industrial chemical plants a few months ago - one of the main points emphasised by the academic giving the talk was that industry refuses to invest in deploying any new technique/approach coming out of research until it is demonstrated that the new approach definitely works at scale. maybe part of "knowing" that it works is having something operational at large-scale and running for long enough to help identify and iron out problems that weren't anticipated during design and smaller scale trials. if it costs hundreds of millions to billions to build the thing you want to guarantee that the approach is solid.
ChuckMcM
I think that is exactly correct, it is also why Facebook and Google have built more data centers in the last 10 years than any of the "established" internet service providers. They operate on a different evaluation strategy, and establishing a source of energy that they controlled and was 'green and unencumbered' has been high on Google's list for a while. They helped build a very large solar farm in the Mohave desert for just that reason.

And they are sitting on billions of dollars of cash that is returning maybe 1.2% in returns.

mozumder
Going beyond the tech into the business side, at $500 million a pop for the smaller SPARC sized fusion reactors. There's an opportunity for startup funding for this. Probably a market of 1,000-10,000 of these smaller reactors around the world, just for the initial first generation.
SCAQTony
Te lecture begins at the 2:20 mark
johnnybowman
Does it mention anything about timeline?
ChuckMcM
The obligatory 10 to 15 years :-)

More seriously though a summary is that you can buy off the shelf high temperature superconductors (HTS) and they allow a Tokamak type architecture to reach break even with a much smaller machine. He wants to build such a machine to prove his statements.

He did not address the question what this means for stellerators (only that they were interesting to watch)

And I found his dismissal of LENR somewhat presumptuous. His point that there isn't any sort of theory yet that is testable experimentally that would explain the results is true, but as far as I can tell the ability to generate results from an experiment that are not explained by existing theory is something to not write off just yet. I agree that it's unlikely in the extreme to have an impact but science has to accept that sometimes the crazy stuff leads to a deeper understanding.

FiatLuxDave
It's been about 25 years since I hung out on Usenet sci.physics.fusion, where there was a lot of debate about cold fusion/LENR back in the day. I remember that the most likely theory I saw was that the extra energy (aside from the widespread calorimetry errors) was coming from the pressure of deuterium within the palladium matrix. It takes hundreds of thousands of psi to load the palladium with deuterium. If you pressurized a scuba tank slowly with thousands of psi, then released the gas in bursts, you'd see a constant energy input with bursts of "excess" energy output, just like cold fusion experiments report. The fact that experimenters using pre-loaded electrodes were more likely to observe "excess" energy seems to corroborate this theory.

Are you aware of any experiment proving or disproving this theory?

Here is a relevant experiment, albeit aimed towards energy storage: http://news.stanford.edu/news/2014/september/battery-palladi...

ted_dunning
If you aren't willing to write of Low Energy Nuclear Reactions AKA cold fusion (had to look that up) by now, when will you think it appropriate?

It is now 30 years on from Pons and Fleischman's famous mistake and we have had a tiny smattering of irreproducible results and a mass of reproducible non-results.

The point about lack of a theory is a nice way to say that there isn't any plausible explanation why researchers who produced watts of excess energy didn't die of either neutron or gamma flux. All of the supposed explanations that I have heard have been tens of orders of magnitude off of the mark.

So what kind of reasonable dismissal of LENR would you find not presumptuous?

ChuckMcM
Hmm, it's a fair question. I pretty much have written off LENR as has most everyone else, my comment was that I try not to disparage people who haven't written it off, I just set my expectations that something that will come from it at zero.

The difference is that I feel it is a perfectly legitimate scientific pursuit to understand what is going on in a LENR experiment producing unexplained results, even if I personally don't expect it to produce any meaningful results. I know its a fine line, I totally dismiss creationists trying to 'prove' that the world is only 6,000 years old, even though they tell me they have approached it 'scientifically.'

tekkk
Cool. I posted this same link two times already. No matter, it's a very interesting video but I'm quite curious how people can get their links to the front page. It seems impossible unless you rapidly gain like tens of upvotes or else it just drops from the new list and goes unnoticed.
crimsonalucard
Did not know tony starks arc reactor was based off of real fusion research. Interesting.
abefetterman
Overall this is presenting a smaller university-class tokamak with advanced superconductors to try to reach Q>2 (scientific breakeven). One of the big advantages of higher fields is that the fusion power goes like B^4. I think this is an interesting idea, but it's hard to imagine the US funding something like this at the same time as ITER. Last year's talk [1] suggests "alternative funding," pointing to other private fusion research, which I am dubious of. There is a mindset that "if these bad ideas get funded, our good idea should get funded more," which we know is not how funding works.

As a former researcher of alternative magnetic confinement schemes, I'm disappointed the latest research in FRCs and mirrors didn't make it into this talk. Viewers should take into account that this, like most talks, is pushing an agenda, in this case a new device called SPARC. It appears to also be a way of using the incredibly talented tokamak researchers at MIT now that Alcator C-Mod is not operating.

[1] http://library.psfc.mit.edu/catalog/online_pubs/iap/iap2016/...

QAPereo
Any breakthroughs on the horizon to tackle the issues of the containment vessel being battered, and the plasma diverter?
abefetterman
The most interesting thing for these is liquid lithium metal--especially a great solution on diverter. For the wall neutron flux this is unfortunately seen as a "materials issue" (someone else's problem). It is a bit stalled out until we can build something with high enough neutron flux for testing.
QAPereo
Exciting news on the liquid Li, but I'm a bit dejected to hear about the wall.
noobermin
But he's from MIT so he must know what he's talking about.

Remember kids--and by kids, I mean fellow scientists--every presentation serves to either help secure or maintain funding.

mozumder
> Remember kids--and by kids, I mean fellow scientists--every presentation serves to either help secure or maintain funding.

What's the point of this statement? Funding is how things happen - these things don't happen out of thin air.

"Remember kids--and by kids, I mean fellow scientists--every presentation serves to either help doing or maintain doing."

ruleabidinguser
It's a reminder not to think the presenter was honestly trying to teach
noobermin
Or not necessarily that there isn't any noble intention in him, of course there is some. But, the pressure of keeping funding will always color their presentations, for example, to make them leave out other competing groups and ideas.
Smaug123
Sometimes a presentation is just a presentation. A means of imparting unbiased knowledge.
tambourine_man
>Viewers should take into account that this, like most talks, is pushing an agenda

Exactly, and it annoyed me a bit the somewhat dismissive tone he applies to the competing ideas. He starts by trying to show an impartial overview while being anything but.

dwaltrip
To be fair, his dismissal was consistent in focusing on the most important metric, Q (energy out / energy in).

However, I'm not qualified to assess anything else in the video, and I do recognize the potential for bias here.

I saw this a while back and thought it was a good summary: https://youtube.com/watch?v=L0KuAx1COEk

I forget the current best efficiency, but it's getting close.

Jun 27, 2017 · 2 points, 1 comments · submitted by theothermkn
theothermkn
The video is long, but worth it. The short version is that recent advances in high-temperature superconductors have realistically reduced the size needed for power-producing tokomaks, putting them within the realm of startups and universities, rather than in the realm of international cooperation and bureaucracy.
> I find it fascinating (and a bit worrying) they are still basically attempting to optimize the same two approaches that were developed in the 50s/60s, tokamak and stellarator.

This would be a bit like worrying that aerospace engineers are still optimizing wings. Like wings, tokomaks/stellarators are the best tools for the job, as dictated by the underlying physics of the systems in question. Basically, donut-shaped magnetically-confined plasmas "leak" into themselves, rather than out into the world.

> Many people have spent their whole careers on it and have died without making significant progress.

This is a popular view that is entirely wrong. The figure of merit, which is the triple product of confinement time, density, and temperature, outpaced Moore's law right up until a gain of about 0.95, when the magnetic technology of the day caused the necessary size increase to put ITER in the realm of international cooperation. ITER absolutely will produce more power than it consumes. The plasma physics are just that well understood. The problem is size.

MIT have recently worked out that a new breed of superconducting magnets can more than double the available field strength, resulting in a 16-fold reduction in reactor size (due to a 4th power gain in confinement strength as a function of field strength). They hope to achieve a gain of about 2 with a university-scale reactor before ITER, designed with the magnets available at the time, is complete.

Most, if not all, of the above comes from https://www.youtube.com/watch?v=L0KuAx1COEk. ARC and SPARC, the MIT reactor concepts, are the most exciting thing I've heard about in...gosh, I guess my whole life. They could pull it off. If they do, we could save the planet with fusion-powered CO2 scrubbing. We could avert disaster.

dmix
That's interesting, I wish I ended the book with that type of optimism. It was a bit disheartening to hear about the many failed starts and the slow down of progress.

But that said it wasn't totally lacking optimism. It was more of the hard reality of how challenging the problem will be to solve.

I still follow the development of it and there is definitely incremental progress.

Thanks for think about MIT's work, that's interesting.

dredmorbius
Wings work for what we want them to do, and have since they were first tried.

Stellarators don't.

Progress has been minimal.

The more so if one recognises the distinction between Texas Sharpshooting -- drawing targets around the holes we've made with various technical methods -- and the actual initial intent.

This particular problem has turned out to be vastly more difficult than anticipated or advertised. I've watched what little progress has been made over more than 40 years.

alimw
> Wings work for what we want them to do, and have since they were first tried.

Pretty sure people have been messing with wings for centuries longer than they have worked.

dredmorbius
What held aircraft back was prime movers, fuel, and materials.

Once petrol-fueled engines and aluminium were available, the Wright beothers were flying within a few years of the Ford Model T. Monocoque airframes followed another few years later. The most perfect aircraft ever, the DC-3, which remains in active commercial use, was developed within the next 3 decades, largely thanks to aluminium alloys. Aivionics and wing design were largely solved by then.

With the gas turbine, jet aircraft appeared, and Boeing is still effectively building and selling scaled-up versions of its 707 airframe (1957). The USAF will be flying the very same aircraft for over 80 years, the B-52. First flight 1952, last date af manufature: 1962.

What progress has been made in aircraft over the last 65 years is largely limited to improved controls (both linkages and avionics), novel materials, and more recently, improved modeling duringg design and development. Outside military applications, that still has exceptionaally limited commercial impacts.

See various sources, though Robert Gordon's The Rise and Fall of American Growth has a good overview.

The contrast, particularly with man-years of effort and billions in spending, to fusion, couldn't be starker.

lwlml
You know, I had a sad thought about fusion-powered CO_2 and that was once it will be built, the energy is likely to be used not for CO_2 scrubbing but instead to mine Bitcoin.
flashman
"Cheap energy means cheap air conditioning. We don't have to change a thing!"
tomaskafka
That's how it worked ever since, including coal and oil. https://en.m.wikipedia.org/wiki/Jevons_paradox
I watched this video called "MIT's Pathway to Fusion Energy (IAP 2017) - Zach Hartwig" which I thought was interesting (and which I submitted here two days ago but went unnoticed as it's the faith of many interesting HN submissions).

https://www.youtube.com/watch?v=L0KuAx1COEk

There Zach gives a quick overview (well hour long) of the current state of fusion and what its future is going to be. He didn't talk too much about stellarators but I feel I have now a better overall understanding of fusion physics thanks to him.

Jun 25, 2017 · 1 points, 0 comments · submitted by tekkk
Apr 28, 2017 · 2 points, 0 comments · submitted by mpweiher
Wendelstein 7-x is really not fusion research, but plasma physics research. At the energy/temperature levels and magnetic field strength this machine is operating, plasma is showing all kinds of undesirable behavior, such as turbulence, radial forces... a little bit like the storms on Jupiter. This imposes many challenges, because as soon as the plasma escapes the magnetic field and touches the vessel, it rapidly cools - ending any potential fusion.

Wendelstein's goal is to find out the viability of the stellarator concept, to see if it could be on par with the Tokamak concept, which so far have shown a better ratio of energy invested and energy won back, but come with their own bag of problems.

What the folks at Wendelstein are doing is a step by step verification of some of the hypothesis. There is this excellent 3h podcast with the scientific leader of Wendelstein [0], unfortunately it is in German. It is fascinating to hear their story on how they build this ultra complex piece of kit. The current change is the shielding of the vessel, which now permits higher energy levels and longer runs. Their long term goal is to operate at 100m K for 30 min.

Regarding the "when we should stop trying" and "it is 30 years out" adage: There has been great progress made in improving the ratio of energy invested and energy won back, the G-factor. Right now no fusion reactor is crossing the G > 1 limit. But Iter would be design to yield about G = 5. Newer designs using high temperature superconductors could even yield G > 10 with a smaller footprint. For more on the current state of fusion research, this video [1] from MIT is fantastic, albeit 1h long.

[0]: http://alternativlos.org/36/

[1]: https://youtu.be/L0KuAx1COEk?t=37m23s

sandworm101
But how much of that G > 1 energy has ever been harvested? I get the impression that very little is being done in regards to extracting energy from a sustained fusion reaction. We can't put solar panels in there, nor can I see how one would extract heat given the cooling needs of the magnets. Is there some sort of medium that we can use to pipe heat energy out of this plasma without destroying it?
PhasmaFelis
> But how much of that G > 1 energy has ever been harvested?

None, because we haven't achieved G > 1 yet. :)

Per https://physics.stackexchange.com/questions/70209/how-is-ene..., hydrogen fusion produces helium and neutrons; neutrons are unaffected by magnetic fields, so they escape confinement and impact the reactor walls, heating them. The heat is simply vented in current test rigs, but in a working model it can be used to produce steam to power generators. That's specifically for tokamaks, but I would guess the process is similar for stellarators.

sandworm101
So if the neutrons are untouched by magnetic fields, don't they also heat the magnets? I can see them passing through walls to boil water, but any heat created in the magnets would be very difficult to harvest given the temperatures involved. How much energy would it take to keep the magnets cool in the presence of a sustained (ie days) fusion reaction nearby? Generating such a flux in a bottle surrounded by things that need to be kept so cool sounds a bit of a fool's errand... but I really want practical fusion to be a thing.
madengr
Water is a good neutron absorber. Maybe the water is in front of the magnets.
wyager
It's great how even our most advanced energy generation technologies are still just steam boilers at heart. That hasn't changed in 305 years.
boznz
The Focus Fusion http://lppfusion.com/ reactor does direct conversion to electricity.

A Shame these guys are the least funded contender in this race and could do their research on a rounding error from ITAR.

djsumdog
Steam initially, but effect ways of converting all that heat to electricity are pretty limited at the moment.

One way to convert the heat from radioactive decay into electricity is through thermocouples (typically found in RTGs used on deep space probes and Mars exploration craft). They're incredibly inefficient though, less efficient than simply turning steam turbines.

zlynx
I've read about some theoretical designs that would open the field to allow all negative charged particles out and use these electrons as power directly.

But first, designs would have to be able to keep the containment pressure/temperature much higher than it currently is.

https://en.wikipedia.org/wiki/Aneutronic_fusion#Energy_captu...

vilhelm_s
The inner surface of the Wendelstein plasma vessel is water-cooled (it has to be, or it would eventually melt), so in the future you could drive a generator from the cooling system.

There is a separate engineering problem about how to keep the plasma vessel from warming the magnets (which need be near absolute zero). In the Wendelstein this works by putting most of the device inside a vacuum, to provide better thermal isolation. So the full system is a vacuum chamber which contains the magnets which wrap around the plasma vessel which wraps around the plasma.

There is an article about the cooling system here: https://www.ipp.mpg.de/ippcms/eng/presse/pi/02_10_pi

DesiLurker
almost all of fusion development is basically plasma physics research. nuclear fusion itself is known science, its the plasma containment & stabilizing that hard. so you can sustain the fusion & get positive yield.

that said I'd much prefer all the money being burnt on ITER/tokamak would be better spent by spreading the bets into exploring concepts like W7 or inertial confinement or even MIT ARC kind of efforts. Grand efforts like ITER are just ensuring fusion is always 30 years out.

My personal prediction is that we'll have fusion positive yield within a decade of when alternative energy becomes a significant portion (say 25% .. & growing) of total energy mix.

zlynx
There really are physics that only work at very large scale, such as stars and black holes.

It may be that we can only get fusion power generation working in huge reactors like ITER. It's also a good attempt at getting many countries working together. Ideally, more big brains working together will have better ideas and results.

There's downsides to ITER too of course. But I think it's worth working on.

Yizahi
ITER is actually a small scale model. Full scale would be DEMO, a few decades in the future :) .
candiodari
There are fusion reactors that are 5 cm diameter. Total size less than a microwave. They're very useful but not energy-positive, though there are reports of one that was Q=0.2, which given that that one was fridge sized was pretty good. They're the only practical way we have of producing fast neutrons.

They are critical in physics research, some medical treatments, fusion research, ... their is absolutely no even remotely practical alternative to them (they're microwave sized devices, using 4-10kw of power that replace synchotrons. Small synchotrons are basketball-field sized and need their own power station) (replace should be taken with a grain of salt since most places that have IEC fusors had no way in hell to afford a synchotron, so they are democratizing fast neutrons. Okay, that's perhaps a strong word but if you have a use for them, there's no reason why you couldn't operate one of these devices in any regular office)

(ps: given how easy, hard to detect, and deadly mistakes with fast neutrons are, please do do it in an office building at least 100m away from me. As it stands though, they're completely unregulated)

The reason we scale up is roughly:

1) Scaling laws work in favor of Q. Q should scale with something like the 3rd power of the size of the reactor. So it's much easier to build a huge Q>1 reactor.

2) Where to stick parts ? Fusion reactors require strong magnetic fields and the only real way we knew of doing that 20 years ago when these were designed was cyronically frozen. That means we need sections inside the reactor for superconductors, for crygenic cooling equipment (mostly piping).

Even disregarding that, fast neutrons will destroy any material they touch, making it brittle and crumble. Aside from bigger reactors making sure more material can get destroyed without failure, one thing that they interact with well is large volumes of water. So if at all possible, we'd like large volumes of water inside the reactor too (for other reasons too, like one strategy for extracting power). That needs space, obviously.

3) It is much easier to keep things stable if their scale is larger. There is more reaction time for the control equipment, the fields involved are larger and move slower, ...

boznz
Got a friend at ITAR, when I asked him how many people work there, he said about 10%
zachrose
Ha, I have the vague sense that that's a joke but I'm not exactly sure what it means?
beamatronic
The joke is that 90% of the people aren't "working".
Yizahi
Except when stellarator starts doing longer runs and requires more hardened materials (like ITER) and when we need more instrumentation in the containment walls (like ITER) and when we need to actually plan to harvest energy from it (like ITER) and somewhere at that point someone proposes yet another concept for fusion reactor, modern and not dragged down by all that "practical" stuff. Also fusion is not 30 years away, it is likely more, after ITER we'll have DEMO, that would take many years again and only after that we may have first practical reactors running.
Mmmh, some of the claims in that article are debunked in this neat video from MIT (though over 1h long): https://www.youtube.com/watch?v=L0KuAx1COEk
leephillips
All his major claims seem correct to me, but my experience in fusion-related research was on the theoretical side. Is there a written summary of what is supposed to be incorrect?
Xorlev
Which claims does it refute? I'm not able to watch the video, but I'm interested.
shaqbert
E.g. the nuclear waste problem: With the right shielding you'll get to radioactive waste that is much easier to handle and usually decaying enough in a 60 year time span. As opposed to the millennia from fission products. So yeah it is a problem, but manageable.

Or the parasitic power consumption problem. Yes, fusion reactors require a lot of energy to power that magnetic field, the cooling for the magnets, but the whole point of fusion research is to get an order of magnitude out of the energy put in, i.e. a G-factor which is > 1. Right now we don't have a fusion reactor that manages G >1, but Iter has the potential to operate around G = 5, and before long some smart kid will figure out a design that gives you G > 10.

The tritium breeding problem. There are indeed some smart solutions like a FLiBe salt blanket fill. Which also is great at absorbing the neutron "waste".

The nuclear proliferation problem. This is more of a theoretical problem, as there are way easier pathways to a bomb. E.g. the thorium fuel cycle to breed a U-233 based bomb is doable even with tech from the 1960'ies.

politicalthrow
That video gives a terrific overview of the landscape of the fusion field as it exists pretty much right now. It's an extremely coherent talk.

It's long but worth the watch.

senectus1
it was mesmerising.. this video needs to spread more.
mrfusion
I think someone needs to let bill gates know about this video. It's very promising and well planned and it really just needs a minimal investment.

Also someone needs to write this stuff up into an engaging article. It's hard to spread the word with an hour long video.

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