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Rezwan wrote:
Value added (for example, solar panels that double as carports in parking lots)

Negative. As solar panels are not self-supporting and are unable to shield a car on their own then you must regard the panels as a burden on the actual carport itself.

Now then, if you park your Prius under an FF unit I can guarantee it will be safe from the hail 😉

Much more seriously: as the storms continuously ramp up in frequency and intensity the ability of a power system to regularly withstand storms that were once considered exceptional will become a serious limitation on system applicability.

edit: did I mention cheaply?

They either must be able to withstand the storms or be able to be repaired quickly, easily and [em]cheaply[/em].

[ADMIN: Note response to this post started new topic: Solar Panel Carport Mosaics]

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MTd2 wrote:

Perhaps one could arrange all this so that the actuators are not crushed and do indeed help the electrodes align better for each shot… but essentially you’ve just introduced moving parts into a system that naturally cycles at hundreds of hertz and is already highly stressed.

Yes, this is the problem of realign the electrodes after each shot. The point of using actuators here is making the system remain at a fixed position.

And that’s my point. The switch electrodes are already supposed to be fixed in position now and as I understand it the switch geometry is still being altered sufficiently by the shots to affect the results. If you build leeway for movement into the system then it is [em]going to move[/em] regardless of actuators.

So, again, the question would be how can you make actuators work for you under those circumstances…

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dennisp wrote: Reminds me of something General Fusion is doing. They’re using steam to drive their pistons, but fine-tuning the timing with electromagnetic brakes.

Yes, but the pistons are supposed to be moving… the electrodes in a classic dpf core are supposed to be stationary for the shot and the mechanical forces applied to them during a pB11 shot are going to yank any movable parts to the limit of their length(s) of travel.

Perhaps one could arrange all this so that the actuators are not crushed and do indeed help the electrodes align better for each shot… but essentially you’ve just introduced moving parts into a system that naturally cycles at hundreds of hertz and is already highly stressed.

So… implementation would seem to be the question.

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Brian H wrote: “Less than background” is catchy, but an unnecessary standard. You can handle much higher levels for a while, especially when it’s declining by factor of 8 every hour.

… or you could sell it as a free PET scan with every core breach…

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Brian H wrote: Yeah, well, that would cut it down to 1/2^27, or about 1/130,000,000. Should be enough.

… except that it won’t be less-than-background in the first hour should an extreme accident vent the core on a road. And the same applies even more so for aircraft applications.

But, annoying as it can be for the prospects of extreme hovercraft sports, that “less-than-background at all times” motif of Lerner-hakase is going to be very good insulation if a justifiably angry public has to be informed that a spent fuel pool in someone’s fission plant has just gone walkies on its own…

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Brian H wrote: AFAIK, there is unstable C12 briefly in the mix, but no C11. Where’s the ref to that?

Referring to the side reaction that’s the reason for the recommended ~9 hour wait after shutdown before accessing an FF core.

http://en.wikipedia.org/wiki/Aneutronic_fusion#Residual_radiation_from_a_p.E2.80.9311B_reactor

Occasionally a p + B11 reaction could produce a C11 and a neutron instead of an overly excited C12. It’s supposed to be one of the sources of what little neutron radiation boron fusion produces.

And the C11 itself has a half-life of ~20 minutes as it turns back into B11 and thus the ~9 hour wait. This would presumably also apply to impromptu core accesses incurred while on the highway…

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Brian H wrote: I think something the size of an 18-wheeler could accommodate one; it wouldn’t need to be “under the hood”.

Or a big, big bus 🙂

… unfortunately the issue of potential C11 release in the event of an accident must govern your planning…

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Milemaster wrote: Henning:

Here are some references on two methods regarding how to generate a hollow laser beam that filled with plasma can be used as an electrode.

?

Are you intending to have these “cylinders” of fuel plasma conduct the power to drive the formation of the sheath?

Then the fuel for the pinch would be in addition to the “electrodes”?

Then are you just shiftingg the erosion to the physical electrodes supplying the current to the plasma within the beams?

And what will that pB plasma external to the confinement beams do to them?

Doesn’t seem to add up, so what am I missing?

Another issue would seem to be that, unfortunately, none of the techniques you mention are scaled to the magnitude of current, pressure and temperature required for pre-pinch plasma.

Milemaster wrote: Finally I do not see any use of beryllium coating cooper electrodes. The x rays would pass trough the beryllium to finally be absorbed inside the cooper core as I understand.

Er… no one mentioned beryllium plating. The electrodes, which are not very large, are to be made of beryllium.

A few threads discussing the resources needed for production of practical FF power units have indicated that the Be needs of an FF economy falls within current Be production capacity.

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MTd2 wrote: I updated the first post. Check that out.

I might be missing something but the mechanical stresses in the switches and core alone would seem more than sufficient to overwhelm your nano-scale adjustment gear.

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Er… environmental stress.?

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DerekShannon wrote: I would definitely encourage focus fusion supporters to help make sure we’re at least mentioned amidst the other fusion news, either in the comments and/or contact the author of the FoFu-omitting article directly–And we’ll keep busy in the lab and try to have some good press release-worthy news soon!….

Would it help if I staggered onto the offending comments thread like a zombie seeking brains and went “… sswitchezzz…” ?

🙂

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Finally went through the GF website, and picked up a couple of mitigating points they left lying around, namely that the “hang time” for the plasmoids in the central vortex is in the range of “hundreds of microseconds”, and the pulse rate for their default 100MW setup is… one Hz.

(Indeed, the whole setup reminds me of Gally’s Hertza Haeon…)

Let’s pile on the penalties and omit the wave going supersonic… sound v in STP lead is ~1.3 km/sec, how much less for liquid lead? And the lithium added to the lead?… and then the vortex…

But even given an WAG penalty of 300-400 m/s the travel time for the wave to cross 1.5 meters to the center of the sphere would still be an order(s) of magnitude shorter than the plasmoid hang time. And thats even when handicapping the wave v big time.

Add a whole second for the vortex to recollect any “mist” and this would seem to make both timing and the mist a non-issue.

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AaronB wrote: I like the General Fusion guys, but I think their approach will run into some difficulties…

Some “Well, buts…”

The basic concept has been known since Trinity and obviously they are going to try to use precision control of the pistons to compensate for any asymmetries of the central vortex. Indeed, their whole shtick relies on that level of control.

As for the extent of those asymmetries? The amount of the widening at each end of the central vortex, and thus the cumulative lensing effects would be determined by how close to full the chamber is at the start and the fluid rotation rate… but that again falls into the realm of calculation and piston control.

They are dancing closer to the edge of bomb code than any other fusion contender except NIF but there should still be plenty of daylight between what they want to do and the verboten zone. (Better be… the last thing the world needs is the oligarch’s favored global reservoir of their poison declaring that fusion is ITAR’d even if Canada and everyone else has it…)

But I don’t think the mist should be as big of a problem as you surmise because the plasma will already be in the middle of the central vortex by the time the wavefronts converge.

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AaronB wrote: Wow. Maybe they’re closer to achieving the fusion dream than we’d thought. 😉

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AaronB wrote: LPP would gladly take $5M in seed money, and do a lot of good things with it. Forget $5M, we’d take $1M and see how close we could come to breakeven!

What could be causing investors to shy off of aneutronics?

Polywell seems to hover on the edge of a government intelligence black hole… or at least Nebel and company have left that impression.

Tri-alpha is secretive but I’m sure having the name Jeff Bezos would result in a red-carpet guided tour complete w/ plushy CBR souvenir.

FF is an open book.

Musing aloud, the only outstanding issues with FF that wouldn’t be solved with net power would be capacitor wear and, to a lesser extent, electrode wear.

LPP seems to have hedged against ‘trode wear by increasing the expected changeouts to a monthly cycle.

Any alternative solutions to cap wear? There’s always that big coil… 😉

… I know, I know…

… but this really does seem like the money is being steered to the least likely candidates… again…

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… and if the 60 C is somehow just unbearable you can lower it to 30 C 😉

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