Small update from Lawrenceville Plasma Physics

[Brian H]

Lerner is asking for assistance in improving/minimizing the size of the 0-ring seals:
http://focusfusion.org/index.php/forums ... read/1022/

Any 'sperts about?

[ladajo]

There are many options on seals. Is he actually using O-rings? Or is he using one time crushables?

The joint designers normally provide ratings based on various torques and seal types. Or is he using a custom joint?

[Brian H]

There are many options on seals. Is he actually using O-rings? Or is he using one time crushables?

The joint designers normally provide ratings based on various torques and seal types. Or is he using a custom joint?

Dunno. Log onto the site at the link and weigh in. I personally wouldn't know a one-time crushable from a 3-time bounce-back!

[CharlesKramer]

Remember, this work is really not in competition with Poly. There's an upper limit to how large a FF reactor can be built and it's a very low limit. We're talking about 10 MW reactor IIRC. Would make a decent thruster if ganged together, but not gonna ever be worth ganging them for GW power. This is really intended for micro-distribution, so it's not in competition with the Poly.

I'm not disagreeing with you -- I don't know enough about it -- but even if you're correct (that it won't scale beyond 10mw) is that necessarily a fatal problem?

1. The device seems very simple -- capacitors pulsing a charge through a ring of copper or beryllium rods in a sealed lightly-shielded chamber, plus some way to direct and process the energy released with each pulse. The total device might (one day) fit into a truck trailer, and be possible to mass produce. Why not stack 1,000 of them -- or 10,000 -- with a few operators to monitor them? Some will periodically fail, and all will need to be serviced (electrode replacement), so you pull non-working modules. I don't know the capital expense of that compared to a traditional power plant, but I believe traditional plants are huge because that's the only way they can produce cheap power. Dense Plasma Focus would be small and much cheaper -- and you customize the stack to the locality.

2. I don't know a lot about the structure of the grid (or physics) but local distribution -- gridless electricity -- would seem to be a good thing. It eliminates the electricity losses and management overhead of long distance transmission.

The sad thing is the grid is a mess anyway -- I believe it uses old equipment, and is not designed for the load-balancing problems for a grid powered by intermittent power sources like wind / solar.

Toshiba is also working on local power -- a self-contained sodium-cooled fission reactor and "micro" sized (I want one). Bury it, use it for 20 years for your town, and Toshiba later picks it up. "DO NOT OPEN Contains no owner serviceable components." Google "Toshiba 4S" (no one actually uses it yet).

CBK

[GIThruster]

. . .even if you're correct (that it won't scale beyond 10mw) is that necessarily a fatal problem?

I don't think it's a problem at all. What I meant was that literally, the Poly and FFR are not in direct competition because they meet different market needs.

We did some rough figuring over at NSF some years ago, and it became obvious that as the size of a system goes up, the Poly benefits greatly. Not just that the poly scales in power output to something like the 7th power of radius (IIRC), but that the power to mass easily favors the Poly over the FFR once you have about a GW. Could be less. We won't know the details until we have working systems, but the parametrics are there already to show the Poly and FFR meet different needs.

When Franklin Meade did the parametric study for USAFRL, they likewise determined the FFR would be the choice for a fusion powered "starfighter" sized craft, but for a larger craft with GW's of power (like a launch vehicle) you'd want a Poly. That's what Bussard had recommended as well. IIRC, George Miley also agrees with these metrics.

For micro-distributed, small capital investment grid needs, lets say a small village in the undeveloped interior of Africa, an FFR (or a few) is the ideal choice. For powering a large piece of grid, say in the NE USA, the Poly will be cheaper to build and maintain, at least according to the metrics developed the last decade or so.

All of this is of course open to reinterpretation once one begins to look at how to shield/capture X-Rays, etc.

I should also add that if the BLP reactor were to work out, it would be useful in instances where the FFR is even too large, like automobiles, robotic interplanetary probes, small general aviation aircraft, etc. Given each of these three show even an off-hand chance of ever working, it seems pretty insane to me that the US is not investing extremely heavily in them. Close down projects like NIF that cannot ever lead to cost effective power generation, and we'd have plenty of money to fund all three and more at accelerated rates.

I'm not in favor of the "bury and forget" fission reactors because I'm not in favor of nuclear proliferation. Seems to me that solution would eventually make fuels and fission products available to the kinds of people who would use them to make dirty bombs. B11 reactors don't have that drawback. It would certainly be in the security interests of the entire world to see B11 reactors distributed as far and wide as possible.

[D Tibbets]

The limit on scaling to _5-10 MW is part of the limits on the FF. That the minimal input power for this output is around a few MW implies that maximum Q's of ~ 2-5 results, and this means that conversion to electricity must be efficient. Thermal conversion at ~ 25 to 30 % wont do it. This is why LLP has emphasized high efficiency conversion of otherwise wasted Bremsstrulung radiation, along with direct conversion of fusion ion energies. Because of the conversion efficiencies, FF devices (if they work) may work better with the difficult P-B11 reaction than it does with the D-D reaction.

You may input ~ 3 times the drive power, and have higher Bremsstrulung, but you will also get ~ 3 times as much energy per fusion reaction, and you may convert this fusion (and Bremsstrulung) power to electrical power at ~ 3 times the efficiency. A side benefit is the near lack of pesky neutrons.

A production FF reactor may take ~ 2 MW to operate, produce 8 MW of fusion power and a net of ~ 4 MW of electrical power. Each reactor would need it's direct converters for fusion ions and X-Rays. To match a Polywell output of perhaps 100 MW net electrical power would require ~ 25 of these FF reactors. I doubt if the economics would favor the FF reactors in this comparison. Also remember that a Polywell could be scaled to higher powers than just 100 MW.
As stated though, they would be more attractive for applications that only required a few MW of power. Such applications might be remote sites like a base in Antarctica, and such applications as locomotives, heavy trucks, large boats (or perhaps backup on a small ship), etc. If the FF reactor can be made a comparable costs to a large windmill, they would presumably be much more reliable. mobile application-

Another issue is the life cycle costs for a FF reactor. Electrode erosion will be a major challenge to overcome.

Dan Tibbets

[Brian H]

Ganged FFs would, if anything, have a lower installed per-Watt cost than stand-alones. And that's in the 5-10¢ range. How large does a Polywell have to get to match that?

There's also the issue of "graceful failure". If a few FFs in a gang of 1,000 go down, that's readily dealt with, and compensated for in real time. A 1GW Polywell down is another matter.

[Jeff Mauldin]

It would be great if both FF and polywell work out so well that we really have to worry about the comparative economics of building and using focus fusion devices and polywells. Tis a consumation devoutly to be wished.

[MSimon]

Ganged FFs would, if anything, have a lower installed per-Watt cost than stand-alones. And that's in the 5-10¢ range. How large does a Polywell have to get to match that?

There's also the issue of "graceful failure". If a few FFs in a gang of 1,000 go down, that's readily dealt with, and compensated for in real time. A 1GW Polywell down is another matter.

Low installed cost per MW is good. But if maintenance is a factor.... And of course in the beginning the plants will need to be manned.

[Brian H]

[

Low installed cost per MW is good. But if maintenance is a factor.... And of course in the beginning the plants will need to be manned.

Operating costs, assuming a full engineering + tech staff team monitoring and on standby per 5-10 units, plus replacement electrodes, plus down time, etc., average out to about 0.2¢/kwh. Capital costs, retired in one year, make up about the same.
The unknown variable is siting costs. Proposals for converting abandoned industrial buildings etc. have been made to keep these minimal. Usually such sites have good local grid connectivity, too.

Fuel costs, of course, are on the order of $5-$10 per MW-year. Invisibly small.

[MSimon]

[

Low installed cost per MW is good. But if maintenance is a factor.... And of course in the beginning the plants will need to be manned.

Operating costs, assuming a full engineering + tech staff team monitoring and on standby per 5-10 units, plus replacement electrodes, plus down time, etc., average out to about 0.2¢/kwh. Capital costs, retired in one year, make up about the same.
The unknown variable is siting costs. Proposals for converting abandoned industrial buildings etc. have been made to keep these minimal. Usually such sites have good local grid connectivity, too.

Fuel costs, of course, are on the order of $5-$10 per MW-year. Invisibly small.

Ah. Well. We have paper estimates. The real world will be different. Usually worse.

The Polywell guys estimate power delivered costing from 50% of current low end prices to 100% for initial units. Improving with development. That of course still leaves 50% of your bill (infrastructure maintenance) untouched. Free electricity is only free if you don't need a grid to deliver it.

[MSimon]

And you haven't even factored in "Current Wars". Look up "Edison Tesla Westinghouse Current Wars" for a cultural education.

[Enginerd]

Fuel costs, of course, are on the order of $5-$10 per MW-year. Invisibly small.

Ah. Well. We have paper estimates. The real world will be different. Usually worse.

The Polywell guys estimate power delivered costing from 50% of current low end prices to 100% for initial units. Improving with development. That of course still leaves 50% of your bill (infrastructure maintenance) untouched. Free electricity is only free if you don't need a grid to deliver it.

That does not however include indirect cost savings -- there would be tremendous indirect cost savings to society from reducing smog, acid raid, pollution, leaking pipelines, coal ash radiation, strip mining, gushing ocean oil wells, oil funded dictators and theocracies, etc, etc, etc. As building polywell based power plants became more modularized and less expensive, many local plants could be built, reducing (though obviously not eliminating) the need for grid infrastructure. These savings would accrue as more plants were built (and old coal plants were converted). Not free, but certainly better. Assuming the polywell works at all, in the real world.

[GIThruster]

While I'm all for dealing directly with the "hidden costs" throughout the energy industry, I think this list above is somewhat misinformed. Burning coal is not generally responsible for smog. Smog comes mostly from burning gasoline, which the Poly will not impact unless we switch to electric cars. There hasn't been a significant problem with acid rain since the 1970's, since sulfer dioxide was removed from automobile exhaust gasses by mandatory use of catalytic converters. To the best of my knowledge, there is no noteworthy trouble with pipelines leaking. Even with all the gushing from the Deep Horizon well in 2010, the Earth still leaks far more oil into our environment naturally than is loosed by pumping it out of the ground. Coal ash radiation is completely insignificant, especially when compared to natural background radiation. And as just stated, the Poly cannot replace oil money sent to nations who misuse it, since the Poly does not replace oil.

This leaves pollution, strip mining and greenhouse gas emissions (if you're concerned about that sort of thing) as serious problems that the Poly may address. Though these are very serious problems, the cost of energy is a more urgent and important issue.

If driving the cost of power down is not a significant outcome of the Poly, the reasons to pursue it are diminished hugely. The price of energy affects all prices within a culture, and generally determines the affluence of the culture. If people are already arguing that power from the Poly will not be cheaper, that's reason enough to abandon the project, IMHO.

We need cheaper energy. I don't especially buy the notion that the Poly can't produce it more cheaply than coal. I also don't think we should be pandering to those whom are ready to accept Poly power at the same price as coal. Seems obvious to me with fuel that is so cheap, the Poly should provide much cheaper power. Since the grid to distribute the power is the same in both instances and the cost of the plant is amortized over decades, the cost of fuel must be the single most distinctive element between the two and that gives the Poly a huge leg up.

[D Tibbets]

Several considerations not taken into account in the post above. The marginal cost savings can contribute tremendously to an economy. Bussard considered engineering and cost estimates. He even proposed an early adoption of a D-D Polywell, in a coal fired power plants. The coal and combuster is idled, the polywell serves as the steam generator, and the rest of the stem plant/ generator is utilized.

A P-B11 direct conversion Polywell would eliminate the need for a high pressure steam system (cooling is still needed). This eliminates a very large cost in coal, or nuclear driven steam plants. Of course there are substitute costs, how the balance works out will (hopefully) be interesting.

Next you have to consider the ~ 10% of electricity lost between the remote plant and the consumer. Practical superconductors, FF, Polywells, or FRCs will change this.

While a Polywell might be scaled to GW sizes, from a piratical standpoint outputs of a few hundred MW will possibly be more attractive.

Finally, and the most important point is that coal, natural gas, and especially oil are limited resources. Whether you argue we will run out in 20 years, 200 years, or 2,000 years- we will run out. And as supplies shrink and demand increases the cost will go up.

The real question in the long term is the cost between nuclear fission of uranium and thorium, and/ or possibly fusion - vs - renewables.

I suspect the wild card here may be photovoltaics. I constantly see claims of improvement in efficiencies. If they ever get to efficiencies of 50-60% with cheap solar panels, things will be more competitive. Of course energy storage would still be an added cost problem.

[EDIT] Rereading the last of the post preceding this one, I realize I misunderstood the point. Cost savings might be considerable, but even if the cost savings are small, the effect is exponential.

Dan Tibbets