MIT's Pathway to Fusion Energy [video] | Hacker News Reader

MIT's Pathway to Fusion Energy [video]

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129 pointsmozumder34 comments

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/...

>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.

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.

Any breakthroughs on the horizon to tackle the issues of the containment vessel being battered, and the plasma diverter?

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.

Exciting news on the liquid Li, but I'm a bit dejected to hear about the wall.

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.

> 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."

Sometimes a presentation is just a presentation. A means of imparting unbiased knowledge.

It's a reminder not to think the presenter was honestly trying to teach

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.

Found this opposing pov: http://thebulletin.org/fusion-reactors-not-what-they%E2%80%9...

Summary in text for those of us that cannot watch a video at present?

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.

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).

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...

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.

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?

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.

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).

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.

That's $2.85 per kWh. Seems impractical

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.

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.

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.

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.

Te lecture begins at the 2:20 mark

Does it mention anything about timeline?

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.

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?

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.'

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...

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.

Did not know tony starks arc reactor was based off of real fusion research. Interesting.

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