No Love For Iter

MSimon · Post by **MSimon** » Sat Aug 01, 2009 4:59 am

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http://www.fastcompany.com/blog/ariel-s ... vice-cheap

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Europe's ITER project is blowing $14 billion on the creation of a nuclear fusion power plant, but the bloated project might be outrun by General Fusion, a Vancouver, Canada startup that claims it can build a prototype plant in under a decade for $500 million--pocket change in nuclear fusion terms.

ITER's project, which won't be ready for nearly 30 years, is so expensive because it uses pricey superconducting magnets (tokamaks) and lasers to contain plasma for a fusion reaction. General Fusion takes a different tactic: the company plans to create a fusion reaction that gives off more energy than is required to sustain it by using low-tech brute force.

More specifically, General Fusion plans to make a metal sphere reactor that spins a liquid mixture of lithium and lead to create a vortex inside the sphere. Two spheromaks, or plasma rings kept together by a self-contained magnetic field, are injected into the sphere to create a target. At the same time, 220 pistons hit the outside surface of the sphere to create a shock wave that hits the plasma, compresses it, fuses the isotopes into helium, and releases energy-filled neutrons captured by the liquid mixture. The energy is extracted from the liquid with a heat exchanger to create steam to spin a power-generating turbine and to continue to run the reactor.

Robthebob · Post by **Robthebob** » Sat Aug 01, 2009 2:27 pm

a form of inertial confinement fusion?

You think they can finally solve the symmetry problem?

I guess polywell is also a form of inertial confinement, but we dont have to worry about symmetry, anymore... gotta worry about other things.

MSimon · Post by **MSimon** » Sat Aug 01, 2009 3:14 pm

Robthebob wrote:a form of inertial confinement fusion?

You think they can finally solve the symmetry problem?

I guess polywell is also a form of inertial confinement, but we dont have to worry about symmetry, anymore... gotta worry about other things.

The guys who designed this are very sharp. They used to design ink jet printer heads. This is similar - just scaled up by a factor of 100,000 or 1,000,000.

I was sceptical at first and for a very long time. Then I did my BOE due diligence and decided that they had a fair chance. I don't like their system (steam plant) as much as I like Polywell but it looks like it could work.

Art Carlson · Post by **Art Carlson** » Thu Aug 06, 2009 7:42 pm

Robthebob wrote:a form of inertial confinement fusion?

It sounds more like magnetic confinement plus adiabatic heating, but I haven't had time to read the docs yet.

JD · Post by JD » Thu Aug 06, 2009 9:27 pm

If it succeeds I'm still not sure how practical it would be in the long run. I do wish them success though, if nothing else such a success would begin breaking the science community's infatuation with ITER.

ZenDraken · Post by **ZenDraken** » Fri Aug 07, 2009 6:06 pm

I may not completely understand how this thing is supposed to work, but I wonder:

1. Does the whole thing spin, pistons and all, or just the reaction chamber?

2. Won't this have to spin fiendishly fast in order to centrifugally force the mass of molten lead-lithium plastered to the equator, sufficient to open a vortex completely through the axis of the chamber?

3. Won't gravity cause the central vortex to have a smaller opening at the bottom of the chamber than at the top? If so, how fast does this have to spin in order to keep the bottom opening large enough for proper operation? Won't this create some kind of asymmetry in the reaction?

4. After being hammered, won't the slightest asymmetry of the mass of lead-lithium cause tremendous vibration until it settles back to the vortex-through-the-center state? How long with that take?

5. Can we even build something like this that won't fly apart with the slightest imperfection or asymmetry?

I dunno. I'm not saying this thing won't work, but thinking about how to make it work gives me a headache!

MSimon · Post by **MSimon** » Fri Aug 07, 2009 6:14 pm

The spin is done by pumping the fluid. The chamber does not spin.

I dunno. I'm not saying this thing won't work, but thinking about how to make it work gives me a headache!

Yeah. The losses are high and only about 10% of te energy put into the pistons winds up compressing the fluid.

And getting the timing right requires continual adjustment of the controls for each piston between cycles. It can't be adjusted on the fly.

ZenDraken · Post by **ZenDraken** » Sat Aug 08, 2009 2:50 am

MSimon wrote:The spin is done by pumping the fluid. The chamber does not spin.

Oh, well that makes me feel a lot better. Thanks!

Yeah. The losses are high and only about 10% of te energy put into the pistons winds up compressing the fluid.

Losses don't bother me too much. Everything has losses.

And getting the timing right requires continual adjustment of the controls for each piston between cycles. It can't be adjusted on the fly.

I'm not worried about that. That's your job, man!

But still: How fast does it have to spin to maintain a central vortex with a reasonably parallel sides from top to bottom?

And since in a 1G environment that vortex will never be have perfectly parallel sides, but will have to taper at least slightly towards the bottom, won't that lead to asymmetries as the shock wave converges on the plasma?

And don't you have to keep the central vortex in a pretty hard vacuum? Won't there be some vapor pressure from the molten lithium-lead?

Sorry to ask so many annoying questions. This is starting to make my head hurt again.

TallDave · Post by **TallDave** » Sat Aug 08, 2009 8:28 am

Losses don't bother me too much. Everything has losses.

In fusion it's a big problem because making stuff fuse is really, really hard and usually takes a lot more energy than you get out. The exception, of course, is fusion bombs, but there the amount of energy released is too great and short-lived to be harnessed for useful purposes.

This is why tokamaks got so much more attention even though IEC could achieve fusion much more easily: toks had far better confinement. On the other hand, they don't seem to have any path to practical use...

This thing looks a bit like a controlled fusion bomb. I'm skeptical there's a useful middle ground between too much power (erosion) and too little (futility), but it's interesting.

TDPerk · Post by **TDPerk** » Sun Aug 09, 2009 1:56 am

I think we know--dead bang

--how to benefit directly from fusion bombs as energy producers. Dig a big hole deep in the ground, with an airlock, suspend the bomb inside a thick water jacket in the middle of the cavern, set it off...

...run turbines off the steam for a week...

do it again...

and so on.

There's never been any reason this can't work, other than politics and economics.

Just little things like that.

ZenDraken · Post by **ZenDraken** » Mon Aug 10, 2009 4:50 pm

TallDave wrote:
Losses don't bother me too much. Everything has losses.
In fusion it's a big problem because making stuff fuse is really, really hard and usually takes a lot more energy than you get out.

I didn't mean to downplay losses, they're really the fundamental fusion power problem. It's just that losses don't give me a headache.

Holding together a rapidly spinning sphere of molten lead-lithium while simultaneously banging on it from all sides, while shooting plasma doughnuts through a hopefully stable and symmetrical central vortex, now that gives me a headache!