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Skunk Works Reveals Compact Fusion Reactor Details

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Re: Skunk Works Reveals Compact Fusion Reactor Details

#261

Post by seanflyon »

rayiner wrote: post #213
jsmthrowaway wrote: post #194

Earlier quoted context omitted.

It's always a safe bet that the top Hacker News comment will always be "won't work, it's too hard." It's like sitting around for a year trying to sell a project at my current employer, with everybody and their lead telling you "that'll never work," then you implement in a weekend and those same people start nitpicking what you've come up with. (What happened to it'll never work? "Well, your CSS isn't great.") Honestl…

That's hardly ever true. In my experience, Hacker News is full of people from the software field; folks whose professions are often unconstrained by physics,[1] and who have a generally optimistic "this can happen" mentality. That's why everyone here believes we'll have fully self-driving cars in 5-6 years. In the rest of the engineering world, the answer to any question is: it'll be harder than you think it'll be (p…

> coal plants, which still make up the majority of U.S. energy production

This is no longer the case.

http://en.wikipedia.org/wiki/Coal_power_in_the_United_States

Re: Skunk Works Reveals Compact Fusion Reactor Details

#262

Post by ufmace »

maxcan wrote: post #209
ufmace wrote: post #161

Earlier quoted context omitted.

That's peak power, though. Basically no street car is designed to be able to produce peak power for more than a minute or two at a time, and probably very few can do it for more than a few seconds. I'm pretty sure that car doesn't have the cooling capacity to cool itself at full power like this plant would have to.

piston powered airplanes run at full or nearly full power for extended periods.

My point may not have been as strong as I thought, but that tends to support it - airplane and boat engines do need to operate at max power nonstop, so they're designed for it. Consumer automobiles usually just accelerate for a few seconds and cruise at relatively modest speed, and I'm pretty sure their cooling and other related systems are designed around that.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#263

Post by munchbunny »

jsmthrowaway wrote: post #194
nabla9 wrote: post #164

I'm not seeing any top physicists working in this program (McGuire is not one). I would be willing to bet 1000 EUR that their math and modeling does not add up, or they have skipped some details. Problem with fusion research like this is that the closer you get self sustainment or energy generation, the harder it gets and problems pile up. This project looks like many other similar projects that have gone bust. They…

It's always a safe bet that the top Hacker News comment will always be "won't work, it's too hard." It's like sitting around for a year trying to sell a project at my current employer, with everybody and their lead telling you "that'll never work," then you implement in a weekend and those same people start nitpicking what you've come up with. (What happened to it'll never work? "Well, your CSS isn't great.") Honestl…

I think people here are generally willing to believe that this is solved if the hard problems are solved. Right now the skepticism is that the hard problems haven't been solved - but that's true of any bet that you make. Either the hard problem has been solved, or you're betting that your people will solve it soon.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#264

Post by tinco »

FiatLuxDave wrote: post #233
hendler wrote: post #205

Earlier quoted context omitted.

http://www.thomasnet.com/products/neutron-shielding-74851395...

The majority of those suppliers provide boron-impregnated plastic, which is fine for e.g. shielding spallation neutrons from a medical linac head. Reactor shielding is orders of magnitude higher, so material damage is a real concern. Not to say that people can't or don't use that material, but it is not the most cost effective stuff. Frankly, the best neutron shielding in the world, on a per-cost basis, is water with…

So in this reactor design, the neutron shield would be quite thin, if that drawing is to scale I'd say like 30-50cm? in that case water in borax wouldn't be dense enough right?

A cool thing about the shield being liquid is that you could theoretically replace it while it's running. It could make the neuron shield double as the heat transfer medium too.

Of course I'm a total layman so this is just highlevel blabbering.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#265

Post by seanflyon »

hackerboos wrote: post #106
nerdy wrote: post #70

I know there are some very smart people at skunk works who've done incredible things in the past but humans have cried wolf so many times on fusion it's sort of hard to just accept until they've actually built a working reactor, shown it and had it independently verified.

We have working reactors they just don't output more energy than they consume. We should be throwing more money at this...

There have even been reactors that produce more energy than they consume, just not in a practical, economical way.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#266

Post by paulmd »

sp332 wrote: post #29
ck2 wrote: post #26

Very cheap energy means cheap war and lots of it. This could be bad.

Cheaper and more plentiful resources means less reason to go to war.

Unlimited free energy means we eventually global-warm our planet through waste heat. Works out at about 10% the potency of greenhouse gasses per MW.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#267

Post by Mvandenbergh »

charonn0 wrote: post #175
regularfry wrote: post #104

Earlier quoted context omitted.

Fusion physicists I know are very sceptical that this design can work. It's a variant on a known design with a known problem: the plasma leaks out of the ends of the magnetic containment. It's also unclear why Lockheed would be publicising it this way at this point, unless it's a naked ploy for more funding from the DoD, and an attempt to bring in money (and possibly pressure) from non-classified sources. That being…

> the plasma leaks out of the ends of the magnetic containment According to this link[1] posted by another commenter, they create a "axisymmetric mirror by positioning zones of high magnetic field near each end of the vessel so that they reflect a significant fraction of plasma particles escaping along the axis of the CFR." [1]: http://aviationweek.com/technology/skunk-works-reveals-compa...

Historically, the problem with the cylinder + mirror configuration is that there are discontinuities (corners) at the seams where the mirrors join on at the end. So you lose a lot of plasma there. Interested to see how they've overcome that.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#268

Post by Mvandenbergh »

dmfdmf wrote: post #125

25 years ago my nuke professor used to scoff at some of the claims of the fusion researchers. The problem is the high energy neutrons flying out of the reactor will neutron-activate every material within the vicinity. He thought the radioactivity and nuclear waste of a fusion reactor could be worse than a fission reactor. Also he thought that fusion researchers were vastly underestimating the problem of neutron embri…

I don't know about the waste being worse, since none of it will be transuranic. All short-lived activation of a few hundred years at most, you could just switch it off and mothball it really.

Totally agreed about the neutron embrittlement, I think that (IFMIF aside) this issue has just been brushed aside as a materials engineering 'detail' to be dealt with as part of commercialisation in a few decades when it might actually make the whole concept of using fusion for energy impractical.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#269

Post by [deleted] »

trhway wrote: post #255
titanomachy wrote: post #215

Earlier quoted context omitted.

"There aren't any top physicists working on this project" isn't really enough to dismiss it outright. The number of brilliant physicists is much greater than the number of top physicists, so it's not unheard of for major developments to come from someone who's not yet highly recognized. McGuire's an MIT Ph.D, so it's likely he's not a complete idiot. I hope they have some novel ideas about neutron containment, though…

>McGuire's an MIT Ph.D, so it's likely he's not a complete idiot. obviously. The proposed reactor looks exactly like a great PhD thesis with honors - a novel field configuration proposed which allows to reach beta of one. The rest of the whole system is given only cursory treatment. In particular how about a "neutron absorbing blanket" in a business-jet size envelope?

[deleted]

Re: Skunk Works Reveals Compact Fusion Reactor Details

#270

Post by tzs »

Osmium wrote: post #191
privong wrote: post #188

Earlier quoted context omitted.

> How much dangerous are the neutrons from such device? Similar to radiation, worst? Neutrons are interesting in that they dump all their energy into a very small region. Instead of losing energy continually and gradually, they travel a ways and then dump all their energy into one spot. This makes them potentially very useful for things like cancer treatment (you can select neutrons to ensure they deliver most of the…

> I suspect this effect means that, for reactors, the wear and tear is more localized, but of a larger amplitude. Not exactly. The initial collisions do indeed cause localised damage cascades, but the overall effect of a large neutron flux is embrittlement of the material. This is a problem already in fission reactor vessels, but the neutron fluxes are a whole order of magnitude larger in fusion reactors, and it's a…

Do the neutrons necessarily come off in all directions, or can the reactor be designed so that the neutrons tend toward specific directions?
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