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Skunk Works Reveals Compact Fusion Reactor Details

aviationweek.com

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Re: Skunk Works Reveals Compact Fusion Reactor Details

#191

Post by Osmium »

privong wrote: post #188
tonyplee wrote: post #185

Earlier quoted context omitted.

How much dangerous are the neutrons from such device? Similar to radiation, worst? Time sell any oil company stocks, mutual fund holding?

> 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 very difficult problem to solve. To my knowledge, current materials can only just about deal with with the neutron fluxes in standard fission reactors, with no current materials being capable of withstanding neutron fluxes in a fusion reactor over any long (i.e. commercial) timescale at present. It would be a big achievement and a big jump in materials science to discover such a material, completely separate of any fusion project.

(Disclaimer: this is not remotely my field, but I have looked at some of this stuff in the past, and been to talks about ITER.)

Re: Skunk Works Reveals Compact Fusion Reactor Details

#192

Post by TrainedMonkey »

cswhatt wrote: post #173
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…

Betting on a math error from Skunkworks? Highly unlikely. If anything, scalability will be the issue, as it always is

Tokamaks were perfect on paper till they were fired up, and then we realized that there is a lot about high energy confinement we did not know about. So I think the math is correct according to current models, but whether those models are close enough to reality for this to work is another question entirely.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#193

Post by was_hellbanned »

The ".NET Rocks!" podcast did three GeekOut shows this year on nuclear fusion, which will probably make you only more skeptical of fusion research claims.

Fusion Power GeekOut: http://www.dotnetrocks.com/default.aspx?showNum=1013

Fusion Power GeekOut #2: http://www.dotnetrocks.com/default.aspx?showNum=1022

Cold Fusion GeekOut: http://www.dotnetrocks.com/default.aspx?showNum=1037

Re: Skunk Works Reveals Compact Fusion Reactor Details

#194

Post by jsmthrowaway »

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.")

Honestly, those folks that stand back with their arms crossed watching you fail, and reminding you the whole way that you might fail, are the biggest pains in my ass in this profession. By a mile.

Maybe you can contribute your wisdom by going to Lockheed, instead of Internet commentary in which you bet against them?

Re: Skunk Works Reveals Compact Fusion Reactor Details

#195

Post by DennisP »

dmfdmf wrote: post #180
DennisP wrote: post #146

Earlier quoted context omitted.

With D-T fusion you would have more activation of the reactor materials, because D-T produces such high-energy neutrons. What you wouldn't have is transuranics, which make up the bulk of our nuclear waste (and all of the really long-lived stuff), or fission products (the most radioactive stuff, like the cesium and strontium we heard about after Fukushima). But D-T is only the easiest form of fusion. Next up is D-D, w…

Correct me if I am wrong, but each of these "steps" is a research project in their own right. The AviationWeekly article mentioned D-T fusion for the Lockheed prototype and includes a diagram with the caption "blanket absorbs neutrons to breed fuel and transfer heat to turbines". This "blanket" will be tons of material that would be activated during operation and would have to be disposed of at EOL. Also, modern mate…

Oh absolutely. There are people trying to jump right into the more advanced reactions, but Lockheed is just aiming for D-T right now. My point is just that D-T could end up being a transitional technology. Once any form of net-positive fusion is available, I'm thinking research will ramp up a lot.

I haven't seen any good quantitative comparisons of D-T waste to fission, now you've got me curious.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#196

Post by baq »

charlysisto wrote: post #133
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.

I followed the ecat ( http://ecatnews.com/ ) story for a year or so until my BS alarm started getting really loud - but just the prospect of it was so exhilarating, it was hard to resist the enthusiasm overflow... Now this sounds way more serious than Andrea Rossi's saga. But I did get a lot tougher on my wait and see stand.

couple either of those to a reactionless drive and head off to alpha centauri for vacation...

Re: Skunk Works Reveals Compact Fusion Reactor Details

#197

Post by al2o3cr »

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...

When you're dealing with a plasma at 20 million kelvin, the leftovers from that "significant fraction" that don't get reflected can really ruin your day...

LLNL scientists almost tested a similar device (see 'MFTF') but the project was cancelled in 1986 before it was turned on.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#198

Post by DennisP »

wcoenen wrote: post #57

> 100-megawatt reactor measuring seven feet by 10 feet, which could fit on the back of a large truck A typical thermal power station has an efficiency below 50% for electricity generation, so the plant dissipates at least as much heat as it generates electrical power. I wonder how you could get rid of 100MW of waste heat from a volume small enough to fit on a truck. That's a heat flux of more than a megawatt per squa…

Sounds like it could make a heck of a launch rocket.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#199

Post by aortega »

dkirtley wrote: post #176
chton wrote: post #18

Earlier quoted context omitted.

It sounds very similar to the way Helion Energy does it ( http://en.wikipedia.org/wiki/Helion_Energy ). Do you know what the major differences are?

Helion here. There are pretty big differences. They did get the high Beta and compact/modular parts right. The primary differences are that Helion operates entirely pulsed with simple non-superconducting magnets. That allows us to go to higher temperatures, cleaner fuels, directly recovery energy, and if everything works as planned should eliminate the wall concerns and need for particle beams. I do think what they a…

If you really are Dr. Kirtley let me say you have one of the most, if not the most important job in earth right now. Fusion energy has the potential to stop wars and re-start the space revolution. I wish you the best.

Re: Skunk Works Reveals Compact Fusion Reactor Details

#200

Post by al2o3cr »

I'd love to know how they're planning on disposing of heat in the magnets themselves - most of the available high-current superconductors prefer to stay close to liquid helium temperatures, which is a challenge when you've set them next to a ten megakelvin plasma that's emitting a 100MW neutron flux...
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